Patent Application
20240041804
The present invention provides for NHE-1 inhibitors and their use in the treatment of coronavirus infections (including SARS-CoV infections and the infectious diseases caused by infection with SARS-CoV, such as and including COVID-19 which is caused by infection with SARS-CoV-2, a coronavirus) and their acute and chronic consequences including life threatening medical complications.
Na+/H+ exchanger type 1 (NHE-1) is the sodium/proton exchanger 1, also named sodium-proton antiporter 1 or SLC9A1 (SoLute Carrier family 9A1), that in humans is encoded by the SLC9A1 gene (Fliegel et al. doi: 10.1007/BF00936442). The sodium-proton antiporter (SLC9A1) is a ubiquitous membrane-bound transporter involved in volume- and pH-regulation of vertebrate cells. It is activated by a variety of signals including growth factors, mitogens, neurotransmitters, tumor promoters and others (Cardone et al. doi: 10.3390/ijms20153694). In normal conditions, NHE-1 maintains intracellular pH (pHi) and volume by removing one intracellular proton (H+) ion in exchange for a single extracellular sodium (Na+) ion (Fliegel. doi: 10.1016/j.biocel.2004.02.006) (see
In certain pathological conditions [e.g., heart failure, cardiovascular diseases, diabetes, Duchenne Muscular Dystrophy (DMD)], NHE-1 is activated, leading to a rapid accumulation of sodium in cells (Fliegel. doi: 10.3390/ijms20102378) and an acidification of the extracellular space. The high sodium concentration drives an increase in calcium (Ca2+) via direct interaction and reversal of the Na+/Ca2+ exchanger (NCX). The resulting accumulation of calcium triggers various pathways leading to cell death (see
The concept of NHE-1 involvement in cardiac pathology has been adopted for decades and is supported by a plethora of experimental studies demonstrating effective NHE-1 inhibition in protecting the myocardium against ischemic and reperfusion injury as well as attenuating myocardial remodeling and heart failure (Evans et al. doi: 10.1016/j.pmrj.2009.04.010). The cardioprotective effects of NHE-1 inhibitors, including Rimeporide, have been extensively studied in various animal models of myocardial infarction and dystrophic cardiomyopathy including DMD (Ghaleh et al. doi: 10.1016/j.ijcard.2020.0.0.31). Other preclinical experiments (Chahine et al. doi: 10.1016/j.yjmcc.2005.01.003; Bkaily and Jacques. doi: 10.1139/cjpp-2017-0265) have underlined the significance of myocardial necrosis, due to pH abnormalities as well as calcium and sodium imbalances in the pathophysiology of heart failure and have demonstrated the beneficial effects of NHE-1 inhibition using Rimeporide in preventing the deleterious effects of Ca2+ and Na+ overload (Bkaily and Jacques. 2017).
NHE-1 activation has also been implicated in various diseases, such as myocardial fibrosis, a key pathology in Duchenne Muscular Dystrophy patients leading to dilated cardiomyopathy, the leading cause of death in these patients. Rimeporide, working through NHE-1 inhibition is cardioprotective in both hamsters (Bkaily and Jacques. 2017) and golden retriever muscular dystrophic dogs (Ghaleh et al. 2020) with reduction in cardiac pathology including fibrosis, left ventricular function and improved survival in hamsters.
NHE-1 is constitutively active in a neoplastic microenvironment, dysregulating pH homeostasis and altering the survival, differentiation, and proliferation of cancer cells, thereby causing them to become tumorigenic. NHE-1 has been shown to contribute to the growth and metastasis of transformed cells. Karki et al. (doi: 10.1074/jbc.M110.165134) have established that B-Raf associates with and stimulates NHE-1 activity and that B-RafV600E also increases NHE-1 activity that raises intracellular pH suggesting Rimeporide could be active in melanoma treatment. Other authors have suggested that NHE-1 inhibitors such as Rimeporide could be truly effective anticancer agents in a wide array of malignant tumors including breast cancer, colorectal cancer, NSCLC (non-small lung carcinoma), glioblastoma and leukemia (Harguindey et al. doi: 10.1186/1479-5876-11-282).
In renal diseases, NHE-1 inhibitor abolished Angiotensin II-induced podocyte apoptosis (Liu et al. doi: 10.1254/jphs.12291fp). suggesting that Rimeporide could also be beneficial to treat nephrotic syndromes such as focal segmental glomerulosclerosis, diabetic nephropathy (Li et al. doi: 10.1155/2016/1802036) and in general in the progression of renal impairment.
Liu et al. (doi: 10.1523/JNEUROSCI.0406-13.2013) have established that misregulation of local axonal ion homeostasis including pH is an important mechanism for axon degeneration and that selective disruption of NHE1-mediated proton homeostasis in axons can lead to degeneration, suggesting that local regulation of pH is pivotal for axon survival.
Hypoxia-induced pulmonary artery hypertension is characterized by elevated pulmonary artery pressure, increased pulmonary vascular resistance, and pulmonary vascular remodeling (Meyrick and Reid. doi: 10.1016/S0272-5231(21)00199-4). With chronic hypoxia there is a rise in pulmonary artery pressure, pulmonary vascular resistance, and a proliferation of pulmonary artery smooth muscle cells. Increased Na+/H+ exchange with an intracellular alkalization is an early event in cell proliferation. This intracellular alkalization by stimulation of Na+/H+ exchange appears to play a permissive role in the pulmonary artery smooth muscle cell (PASMC) proliferation of vascular remodeling. Inhibition of NHE-1 prevents the development of hypoxia-induced vascular remodeling and pulmonary hypertension (Huetsch and Shimoda. doi: 10.1086/680213).
NHE-1 inhibition leads to: Normalization of intracellular sodium, calcium and pH, thus improving cellular function and reducing muscular edema; prevention of progressive congestive heart failure; regulation of inflammatory processes; prevention of fibrosis. NHE-1 inhibitors thus have the potential to address key pathophysiological processes and improve cellular health in DMD (Duchene Muscular Dystrophy) and heart failure models by restoring ion homeostasis. Known NHE-1 inhibitors are for example Rimeporide, Cariporide, Eniporide which all belong to the class of benzoyl-guanidine derivatives (based on a phenyl ring), or amiloride, EIPA (5-(N-ethyl-N-isopropyl)amiloride), DMA (5-(N,N-dimethyl)amiloride), MIBA (5-(N-methyl-N-isobutyl)amiloride) and HMA 5-N, N-(hexamethylene)amiloride which belong to the class of pyrazinoyl-guanidine derivatives (based on a pyrazine ring).
The chemical names and chemical structures of some selected NHE-1 inhibitors are as follows.
Coronaviruses (CoVs) are positive-sense, single-stranded RNA (ssRNA) viruses of the order Nidovirales, in the family Coronaviridae. There are four sub-types of coronaviruses—alpha, beta, gamma and delta—with the Alphacoronaviruses and Betacoronaviruses infecting mostly mammals, including humans. Over the last two decades, three significant novel coronaviruses have emerged which transitioned from a non-human mammal host to infect humans and cause disease: the Severe Acute Respiratory Syndrome (SARS-CoV-1) which appeared in 2002, Middle East respiratory syndrome (MERS-CoV) which appeared in 2012, and COVID-19 (SARS-CoV-2), a betacoronavirus, which appeared in late 2019. In the first five months of identification of SARS-CoV-2, over 17 million people are known to have been infected, and almost 680 000 people are reported to have died. Both numbers likely represent a significant undercount of the devastation brought by the disease.
Coronaviruses (CoVs) are a group of large and enveloped viruses with positive-sense, single-stranded RNA genomes and they contain a set of four proteins that encapsidate the viral genomic RNA: the nucleocapsid protein (N), the membrane glycoprotein (M), the envelope protein (E), and the spike glycoprotein (S). To enter host cells, coronaviruses first bind to a cell surface receptor for viral attachment. SARS coronavirus (SARS-CoV) uses angiotensin-converting enzyme 2 (ACE2) as a receptor to enter target cells. Subsequently, SARS-CoVs enter the host cells via two routes: (i) the endocytic pathway and (ii) non-endosomal pathway. Among them, the endocytic pathway is of particular importance (Shang et al. doi: 10.1073/pnas.2003138117).
The transmembrane spike (S) glycoprotein at the SARS-CoV surface binds to ACE2 to enter into host cells. S comprises two functional subunits responsible for binding to the host cell receptor (S1 subunit) and fusion of the viral and cellular membranes (S2 subunit). For all CoVs, S is further cleaved by host proteases at the so-called S2′ site located immediately upstream of the fusion peptide. This cleavage has been proposed to activate the protein for membrane fusion via extensive irreversible conformational changes. Low pH is required to activate the protease (among which cathepsin L) and ensure endosomal entry. As a conclusion, coronavirus entry into susceptible cells is a complex process that requires the concerted action of receptor-binding and pH-dependent proteolytic processing of the S protein to promote virus-cell fusion. (Walls et al. doi: White and Whittaker. doi: 10.1111/tra.12389). The S protein is also a critical antigenic component in currently approved COVID-19 vaccines, as well as those still within the development pipeline. It can be part of the attenuated or inactivated virus, administered as a protein subunit stimulant itself or incited through genetic instruction to be produced as an antigenic stimulus by, for example, mRNA. It functions to prime the immune response to enable vaccine recipients to mount an appropriate and efficient disease-limiting immune response to SARS-CoV-2 infections and aid in limiting virus transmission.
SARS-CoV-2 closely resembles SARS-CoV-1, the causative agent of SARS epidemic of 2002-03 (Fung and Liu. doi: 10.1146/annurev-micro-020518-115759). Severe disease has been reported in approximately 15% of patients infected with SARS-CoV-2, of which one third progress to critical disease e.g., respiratory failure, shock, or multiorgan dysfunction (Siddiqi et al. doi: Zhou et al. doi: 10.1016/S0140-6736(20)30566-3). Fully understanding the mechanism of viral pathogenesis and immune responses triggered by SARS-CoV-2 would be extremely important in rational design of therapeutic interventions beyond antiviral treatments and supportive care.
Severe acute respiratory syndrome (SARS)-Corona Virus-2 (CoV-2), the etiologic agent for coronavirus disease 2019 (COVID-19), and one of the largest viral RNA genomes known (#30 kb), has caused a pandemic affecting over seventeen million people worldwide with a case fatality rate of 2-4% as of July 2020. The virus has a high transmission rate, likely linked to high early viral loads and lack of pre-existing immunity (He et al. doi: 10.1038/s41591-020-0869-5). It causes severe disease especially in the elderly and in individuals with comorbidities such as increased age, cardiac diseases, diabetes, and patients with a vulnerable heart. The global burden of COVID-19 is immense, and therapeutic approaches are increasingly necessary to tackle the disease. Intuitive anti-viral approaches including those developed for enveloped RNA viruses like HIV-1 (lopinavir plus ritonavir) and Ebola virus (remdesivir) have been implemented in testing investigational drugs (Grein et al. doi: 10.1056/NEJMoa2007016; Cao et al. doi: 10.1056/NEJMoa2001282). But given that many patients with severe disease present with immunopathology, host-directed immunomodulatory approaches are also being considered, either in a staged approach or concomitantly with antivirals (Metha et al. doi: 101.1016/S0140-6736(20)30628-0; Stebbing et al. doi: 10.1016/S1473-3099(20)30132-8).
Numerous variants of the virus have emerged since late 2020. Classes of SARS-CoV-2 variants have been defined as follows in order of degree of global public health significance: Variant of Concern, Variant of Interest and Variant of High Consequence, [(CDC. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html (Accessed: 8 Jul. 2021)]. Variants of Concern are the most threatening due to the risk, as compared to other variants, of an associated increase in transmissibility or detrimental change in COVID-19 epidemiology, or increase in virulence or change in clinical disease presentation; or effect on decreasing the effectiveness of public health and social measures or available diagnostics, vaccines and therapeutics [(WHO. https://www.who.intientactivitiesitracking-SARS-CoV-2-variants/(Accessed: 8 Jul. 2021)]. As of mid-July 2021, Alpha, Beta, Gamma and Delta variants were all still categorized in the Variant of Concern class. Other variants include Eta, Epsilon, Kappa, Lambda, Iota, Theta and Zeta, and it is expected that new variants will continue to surface as the pandemic evolves. The definition of SARS-CoV-2 according to this patent application encompasses all the identified and as yet unidentified variants at the time of writing this patent application.
COVID-19 is a spectrum disease, spanning from barely symptomatic infection to critical, life-threatening illness. All three coronaviruses (SARS-CoV-1, MERS-CoV and SARS-CoV-2) induce exuberant host immune responses that can trigger severe lung pathology, inflammatory cytokine storm, myocardial injury leading to a worse prognosis and ultimately to death in about 10% of patients (see
The occurrence and severity of Acute lung Injury (ALI) are a major determining factor of the prognosis of patients with SARS-CoV-2 infection and COVID-19 disease. About 30% of patients with COVID-19 disease in Intensive Care Unit (ICU) developed severe lung edema, dyspnea, hypoxemia, or even Acute Respiratory Distress Syndrome (ARDS). ARDS is defined clinically by the acute onset of hypoxemia associated with bilateral pulmonary infiltrates (opacities on chest imaging), which are not explained by cardiac failure, and which can lead to mild, moderate, or severe hypoxemia. The syndrome is characterized by disruption of endothelial barrier integrity and diffuse lung damage. Imbalance between coagulation and inflammation is a predominant feature of ARDS, leading to extreme inflammatory response and diffuse fibrin deposition in the vascular capillary bed and alveoli. Activated platelets participate in the complex process of immunothrombosis, which is a key event in ARDS pathophysiology.
Thrombosis has been shown to contribute to increased mortality in COVID-19 patients. It can lead to a pulmonary embolism (PE), which can be fatal, but also higher rates of strokes and heart attacks are observed in patients with thrombosis. This was confirmed in several retrospective studies and provides a rationale for using anticoagulant therapies to prevent thrombosis.
A recent Dutch study of 184 patients with COVID-19 pneumonia admitted to an intensive care unit (ICU) found a 49% cumulative incidence of thrombotic complications despite thromboprophylaxis (Klok et al. doi: 10.1016/j.thromres.2020.04.041). Postmortem studies are finding clots in the capillaries of the lungs in COVID-19 patients, restricting the oxygenated blood from moving through the lungs.
Tang et al. (doi: 10.1111/jth.14768) reported on significantly higher D-dimer and poor prognosis in 183 consecutive patients with COVID-19 pneumonia). Those who did not survive their illness compared with survivors had higher D-dimer level as well as other fibrin(ogen) degradation products (FDP). Abnormal coagulation parameters were evident early after hospitalization and in some patients, fibrinogen concentrations and antithrombin activity decreased over time. The same investigators (Tang et al. 2020) reported in 445 patients that anticoagulant therapy, primarily with low molecular weight heparin (LMWH) administered for 7 days or longer was associated with a lower 28-day mortality.
Helms et al. (doi: 10.1007/s00134-020-06062) reported the occurrence of thrombotic events among 150 patients with COVID-19 and ARDS admitted to the ICU; 16.7% of patients experienced a pulmonary embolism.
Ackermann et al. (doi: 10.1056/NEJMoa2015432) have observed the lungs from deceased patients with COVID-19 and observed that patients had widespread vascular thrombosis with microangiopathy and occlusion of alveolar capillaries.
D-dimer belongs to the fibrin(ogen) degradation products that are involved in platelet activation. Elevated D-Dimer in patients with COVID-19 at the time of hospital admission, is a predictor of the risk of development of ARDS, PE and death. Zhou et al. (2020) reported that D-dimer levels>1 microgram per milliliter (ug/mL) at hospital admission is a predictor of a worse prognosis and of death.
International consensus on the treatment of coagulopathy in patients with COVID-19 calls for low molecular weight heparin (LMWH) or other anticoagulants administered at prophylactic doses pending the emergence of additional data in patients who are eligible to receive thromboprophylaxis. However, thromboprophylaxis using LMWH/antiplatelet agents/anticoagulants can only be used in patients where the risk of bleeding does not exceed the risk of thrombosis. While many unanswered questions remain about the mechanisms of COVID-19-associated coagulopathy, mean platelet volume (as measured by increased platelet volume and size) is another biomarker used in other diseases of platelet function and activation. Some studies also suggest that platelet volume correlates with increased risk for cardiovascular morbidity and mortality. Increased mean platelet volume has been identified as a risk factor in patients with metabolic syndrome, myocardial infarction, ischemic stroke (Tavil et al. doi: 10.3109/09537101003628421; Greisenegger et al. doi: 10.1161/01.STR.0000130512.81212.a2). NHE-1 plays a large role in platelet activation. Thrombus generation involves NHE-1 activation and an increase in intracellular Ca2+, which results from NHE-1-mediated Na+ overload and the reversal of the Na+/Ca2+ exchanger. Rimeporide could be a safe approach alone or in combination with LMWH to efficiently minimize/prevent thrombotic events in COVID-19 patients.
While still speculative, long-term pulmonary consequences of COVID-19 pneumonia in patients who have recovered may include development of progressive, fibrotic irreversible interstitial lung disease such as interstitial pulmonary fibrosis, or pulmonary hypertension. Small degree of residual but non-progressive fibrosis can result in considerable morbidity and mortality in an older population of patients who had COVID-19, many of whom will have pre-existing pulmonary conditions.
The majority of COVID-19 cases (about 80%) are asymptomatic or exhibit mild to moderate symptoms (fever, fatigue, cough, sore throat and dyspnea), but approximately 15% progresses to severe pneumonia (Cantazaro et al. doi: 10.1038/s41392-020-0191-1). Excessive inflammatory innate response and dysregulated adaptive host immune defense may cause harmful tissue damage both at the site of virus entry and at systemic level. Such excessive pro-inflammatory host response in patients with COVID-19 has been hypothesized to induce an immune pathology resulting in the rapid course of acute lung injury (ALI) and ARDS, Cardiogenic Shock or multiorgan failure in particular in patients with high virus load. Prior experience from treating SARS-CoV and MERS-CoV have shown that controlling inflammatory responses through immunomodulators are effective measures to improve the prognosis of human Coronavirus infection (Arabi et al. doi: 10.1093/cid/ciz544). This can be achieved by using immunomodulators such as corticosteroids and cytokine antagonists [for example anti interleukin (IL)-6] but such treatments carry their own risks to delay the clearance of the virus by inhibiting the ability of the body's immune defense mechanism and ultimately leading to adverse consequences. Increased vascular permeability is also a hallmark change that occurs in the process of a cytokine storm. Drugs aiming at improving vascular permeability or inhibiting the mononuclear/macrophage recruitment and function could also alleviate the storm of inflammatory factors triggered by SARS-CoV-2 infection and COVID-19 disease. Such drugs are seen as an interesting complement and as a safer therapeutic approach that would not compromise the host immune response and potential delay of virus clearance.
The cardiovascular manifestations induced by SARS-CoV-2 infection and COVID-19 disease have generated considerable concern. The overall case fatality rate was 2.3 to 4% but the mortality reached 10.5% in patients with underlying cardiovascular diseases (Babapoor Farrokhran et al. doi: 10.1016/j.lfs.2020.117723). COVID-19 related heart injury can occur in several ways and can be caused by the virus itself or is a byproduct of the body's reaction to it (see
First, patients with preexisting cardiac diseases are at greater risk for severe cardiovascular and respiratory complications. Second, people with undiagnosed heart disease may be presenting with previously silent cardiac symptoms unmasked by the viral infection. Third, some patients may experience heart damage mimicking heart attack injury even without preexisting atherosclerosis (myocardial infarction type 2). This scenario occurs when the heart muscle is starved for oxygen which in COVID-19 patients is caused by a mismatch between oxygen supply and oxygen demand due to the pneumonia. The consequences of the lack of oxygen supply result in ischemia of the myocardium leading to ischemia reperfusion injury to the myocardium: Ischemia causes regional scarring of the heart, which is irreversible and can lead to arrythmias. Myocarditis in COVID-19 patients can also occur and lead to cardiac hypertrophy and injury through the activation of the innate immune response with release of proinflammatory cytokines leading to altered vascular permeability. Huang et al. (doi: 10.1016/S0140-6736(20)30183-5) reported that 12% of patients with COVID-19 were diagnosed as having acute myocardial injury, manifested mainly by elevated levels of high-sensitivity troponin I (TnI). From other recent data, among 138 hospitalized patients, 16.7% had arrhythmias and 7.2% had acute myocardial injury.
In another case series, Guo et al. (doi: 10.1001%2Fjamacardio.2020.1017) reported that triage of patients with COVID-19 according to the presence of underlying cardiovascular disease or risks and the presence of elevated plasma cardiac biomarkers (N-terminal pro-brain natriuretic peptide and Troponin T levels) is needed to prioritize treatments and propose more aggressive treatment strategies in view of the increased risk for a fatal outcome and/or irreversible myocardial injury in these patients. Some patients will be predisposed to suffer from long-term damage, including lung injury and scarring, heart damage, and neurological and mental health effects. Such long-term damage is referred to as long COVID as defined below. Preliminary evidence, as well as historical research on other coronaviruses like severe acute respiratory syndrome 1 (SARS-CoV-1) and Middle East respiratory syndrome (MERS), suggests that for some patients, a full recovery might still be years off. COVID-19 survivors may experience long-lasting cardiac damage and cardiovascular problems, which could increase their risk for heart attack and stroke. Some cited and emerging cardiopulmonary pathological observations in patients with long COVID frequently include manifestations of cardiac fibrosis and scarring on imaging, pulmonary interstitial fibrosis (Nalbandian et al. doi: 10.1038/s41591-021-01283-z; Ambardar et al. doi: 10.3390/jcm10112452), as well as implicating it in pulmonary vascular injury and remodeling (Dai and Guang. doi: 10.1177/1470320320972276; Suzuki et al. doi: 10.1101/2020.10.12.335083). Cardiac fibrosis predisposes the heart to functional and structural impairment. The lung fibrosis and pulmonary vascular changes can impact the heart too, by leading to pulmonary arterial hypertension and consequent right ventricular adaptation, with right ventricle failure in the long term if compensatory mechanisms fail.
While there are many therapies being considered for use in the treatment of COVID-19, there remains no single therapy effective against COVID-19 and no cure yet. A combination of therapies administered at different stages of infection may provide some benefit (Dong et al. doi: 10.7189/jogh.11.10003). To date, treatment typically consists of the available clinical mainstays of symptomatic management, oxygen therapy, with mechanical ventilation for patients with respiratory failure. The World Health Organization (WHO), regularly updates their recommendations on COVID-19 treatment based on the most up to date clinical trials, and after more than 18 months since the start of the pandemic, only 2 treatments have received strong recommendations for their use in COVID-19, viz. systemic corticosteroids and IL-6 receptor blockers (tocilizumab or sarilumab), but again not sufficient for widespread therapy as they are both limited to treatment administration in patients with severe or critical COVID-19 disease [WHO. https://www.whoint/publications/i/item/WHO-2019-nCoV-therapeutics-2021.2 (Accessed: 9 Jul. 2021)], Only one treatment has received regulatory approval from the FDA, viz. Remdesivir, and it is limited to hospitalized patients. Moreover, many experts remain skeptical of its benefits [Wu et al. https://www.nytimes.comiinteractive/2020/science/coronavirus-druo-treatments.html (Accessed: 4 Aug. 2021)] due to there being no statistically significant evidence that it prevents death from COVID-19 and with the WHO conditionally recommending against its use in hospitalized patients with COVID-19 [WHO. https://www.whoint/publications/i/item/WHO-2019-nCoV-therapeutics-2021.2 (Accessed: 9 Jul. 2021)]. Notably too, is the fast changeover in treatment advice, with previous agents advocated and thought to be beneficial as treatment in the earlier stages of the pandemic, such as hydroxychloroquine and lopinavir/ritonavir, later having been shown to not be promising as more data has emerged over the pandemic time-course. The treatment landscape is thus complicated.
SARS-CoV-2 is an RNA virus and it is known that RNA viruses are more prone to changes and mutations compared to DNA viruses. Apart from the technological and manufacturing challenges, a successful vaccine strategy against COVID-19 is highly dependent on COVID-19 mutations and on how long the immunity will last against the virus. There are already concerns regarding the effectiveness of currently approved vaccines against emerging virus variants, especially with regards to limiting virus transmission (e.g., the Delta variant). As such we are aware that safety proffered by vaccines are only good if vaccine development keeps pace with viral evolution and there is timely deployment, with universal coverage, the latter remaining a pervasive challenge of any vaccine strategy.
The growing burden of disease, uncertainty around disease impact (e.g. long COVID manifestations, long-term complications), the indeterminate boundaries of virus variants and their implications on disease presentation, progression and pandemic trajectory; the unknowns regarding vaccine side-effects (acute and long-term); and the many other moving targets associated with the pandemic, highlights the ongoing and urgent need for novel, safe, effective, and efficient medications to prevent infection with SARS-CoV-2, address the different stages of the SARS-CoV-2 infectious cycle (Siddiqi et al. 2020), treat the subsequent COVID-19 disease and all its associated complications and life-threatening consequences (acute, sub-acute, long-term, chronic complications and their various organ manifestations, etc.), improve patient prognosis, as well as handle any vaccine-related side-effects.
Additionally, it is also important to bear in mind that the use of experimental treatments (such as hydroxychloroquine and azithromycin) may have cardiotoxic effects or potent immune-suppressive effects (e.g., tocilizumab, corticosteroids), which may compromise the host immune response and accompanying viral clearance, which could complicate the course of SARS-CoV-2 infected patients. There is therefore an impetus for treatments addressing virus clearance and its wide range of symptoms, that in addition to general treatment of patients with a confirmed diagnosis of SARS-CoV-2, they are safe and efficacious in patients whom the currently administered therapies may be contra-indicated in or where the risks are not clearly delineated from the benefits but where no other therapeutic choice exists, for example: (1) for SARS-CoV-2 infected individuals with preexisting cardiac problems to prevent worsening of these problems during or after SARS-CoV-2 infection, (2) for at risk patients who have an increased risk of morbidity and mortality (e.g. elderly patients, patients with cardiac disease, diabetic patients, patients with an underlying condition manifesting with or predisposing them to cardiac complications, etc., (3) in patients with perturbed coagulation biomarkers who are at greater risk of developing thrombotic events, (4) for patients with cardiac injury due to COVID-19 (among those who survive from SARS-CoV-2 infection), and for those suffering with long-term complications of SAR-CoV-2 infection, long COVID and its many manifestations.
In one embodiment, the invention provides NHE-1 inhibitors, or pharmaceutically acceptable salts thereof, for use in the treatment of viral infections and their acute and chronic life-threatening complications in a subject in need thereof. In one aspect of this embodiment, the viral infection is a coronavirus infection. In one aspect of this embodiment, the viral infection is a SARS-CoV-1, MERS-CoV, or SARS-CoV-2 infection. In one aspect of this embodiment, the viral infection is a SARS-CoV-2 infection and any of its variants.
One embodiment is a method of treating a coronavirus infected subject in need thereof, comprising administering an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In a preferred embodiment, the subject is infected by SARS-CoV-2 or any of its variants. In one aspect of this embodiment, the subject has a confirmed diagnosis of COVID-19 pneumonia. In another aspect, the subject has COVID-19 myocardial injury, or the subject has COVID-19 and underlying cardiac diseases, wherein the term “cardiac disease” includes hypertension, coronary artery disease and diabetes. According to a further embodiment, the subject is suffering from cardiac complications with elevated cardiac markers of myocardial injury, e.g., elevated serum/plasma levels of Troponin I/T, increased levels of N-terminal-pro hormone Brain-type Natriuretic Peptide (NT-proBNP), increased CRP, LDH or D-Dimer. In another aspect, the subject is suffering from a hyperinflammatory host immune response due to a SARS-CoV-2 infection, from endothelial cell dysfunction, thrombosis, ALI and/or ARDS. In another embodiment, the subject has a confirmed diagnosis of COVID-19 and is at risk of developing a severe form of COVID-19 because of age, underlying cardiac disease, hypertension, diabetes, coronary heart disease etc.
Another embodiment is a method of treating a subject who is suffering from long COVID, presenting with long COVID, having clinical manifestations, organ effects of long COVID or displaying pathological changes or long-term complications associated with long COVID, comprising administering an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In a particular aspect, long COVID includes the development of new-onset pulmonary arterial hypertension subsequent to SARS-CoV-2 infection (as a consequence of or due to increased predisposition because of SARS-CoV-2 infection) or the worsening of pre-existing pulmonary arterial hypertension present before SARS-CoV-2 infection and the potential consequent effects of right ventricle adaptation, hypertrophy, in response to pulmonary artery hypertension and eventual maladaptation with right ventricle fibrosis and ultimately right ventricle failure. In another aspect the subject suffering from long COVID has pulmonary fibrosis and the administration of the NHE-1 inhibitor improves the pulmonary fibrosis.
Another embodiment is a method of treating a subject who has received a SARS-CoV-2 vaccination, comprising administering an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In a particular aspect, the subject suffers from SARS-CoV-2 vaccination induced complications, such pulmonary arterial hypertension, myocarditis or pericarditis or fibrosis resulting from vaccination induced myocarditis and pericarditis. In another aspect, the subject has pre-existing pulmonary arterial hypertension and the NHE-1 inhibitor is administered in order to prevent SARS-CoV-2 vaccination induced worsening of the pulmonary arterial hypertension.
Another embodiment is an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, for use in treating a coronavirus infected subject, or a subject suffering from long COVID, presenting with long COVID, having clinical manifestations, organ effects of long COVID or displaying pathological changes or long-term complications associated with long COVID or a subject who has received a SARS-CoV-2 vaccination.
Another embodiment is the use of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, in the preparation of a medicament for the treatment of a coronavirus infected subject or a subject suffering from long COVID, presenting with long COVID, having clinical manifestations, organ effects of long COVID or displaying pathological changes or long-term complications associated with long COVID or a subject who has received a SARS-CoV-2 vaccination.
Because NHE-1 inhibitors have a general mode of action that restores the metabolism of the cells that are perturbed during SARS-CoV-2 infection and COVID-19 disease, NHE-1 inhibitors provide a unique approach to control the viral infection and prevent its wide range of symptoms in COVID-19 patients and in particular in those who are at risk of a severe form (e.g., older patients, patients with diabetes, with a vulnerable heart, with underlying cardiac disease). NHE-1 inhibitors also provide an approach to mitigate the deleterious right ventricle (RV) function outcomes and/or ameliorating RV dysfunction that occurs as result of infection with SARS-CoV-2 and its variants.
Another embodiment of the present invention is a method of treating a coronavirus infected subject in need thereof comprising administering a safe and effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, wherein the administration stabilizes or reduces the viral load in the subject. In one aspect of this embodiment, the NHE-1 inhibitor is administered in subjects with a confirmed diagnosis of COVID-19 to prevent developing a severe cytokine storm. In another aspect of this embodiment, the NHE-1 inhibitor is administered to prevent myocardial injury, arrythmia, myocarditis or heart failure, and in another embodiment, NHE-1 is administered to prevent thrombosis. In a further aspect of this embodiment, the subject has a mild to moderate SARS-CoV-2 infection and the NHE-1 inhibitor is administered to prevent the development of heart failure, excessive host immune response, thrombosis, and progression to severe disease. In an additional aspect of this embodiment, the subject has a confirmed diagnosis of SARS-CoV-2 but is asymptomatic at the start of the administration regimen, yet is predisposed to increased severity and mortality associated with the virus because of preexisting and underlying cardiac disease and its risk factors (e.g., diabetes and hypertension).
In another embodiment, an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, is given in a prophylactic manner to prevent effects and complications (acute and long-term) of SARS-CoV-2 infection and/or to stabilize and/or reduce progression of other existing disease and pathological states in a patient infected with SARS-CoV-2, at all stages and in all forms of expression of COVID-19 disease (acute, post-acute, long COVID, chronic, etc.). Therefore the present invention also relates to a method of treating a subject in need thereof comprising administering a safe and effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, wherein the treatment is in a prophylactic manner to prevent effects and complications of SARS-CoV-2 infection and/or to stabilize and/or reduce progression of other existing disease and pathological states in a patient infected with SARS-CoV-2, at all stages and in all forms of expression of COVID-19 disease.
In all of the above embodiments, the NHE-1 inhibitor may be selected from the group consisting of Rimeporide, Cariporide, Eniporide, Amiloride or a pharmaceutically acceptable salt thereof. Preferably, the NHE-1 inhibitor is Rimeporide or a pharmaceutically acceptable salt thereof.
Given the need for therapies to address the life-threatening complications of COVID-19, small molecule compounds, such as NHE-1 inhibitors, may be a valuable therapeutic intervention in providing relief to COVID-19 patients. The compounds of the invention are known to restore basic cell metabolism involving ion homeostasis and inflammation. Such compounds have shown antiviral properties through pH regulation and protein E interactions. The compounds have also shown benefit in improving inflammation, in preserving heart function, in preventing thrombosis, in protecting from fibrosis, without compromising viral clearance.
At the initial antiviral response phase (see
Treatments addressing the severe complications of SARS-CoV-2 are proposed either in a staged approach to prevent excessive host immune response, cardiovascular and pulmonary complications, and organ failure concomitantly with antivirals in patients with progressive disease (see
Cardiovascular complications are known and have already been described with MERS-CoV and SARS-CoV. Myocardial injury (MI) in SARS-CoV-2 patients is not a common sequelae and optimal management for myocardial injury associated with COVID-19 patients has not been determined. It is based on supportive care using off label treatments. Chloroquine and azithromycin have to be used with great care in these patients as they are known to be cardiotoxic and/or to increase corrected QT (QTc) intervals. In patients with SARS-CoV-2 infection and COVID-19 disease, NT-proBNP levels increased significantly during the course of hospitalization in those who ultimately died, but no such dynamic changes of NT-proBNP levels were evident in survivors (Guo et al. 2020). NT-proBNP elevation and malignant arrhythmias were significantly more common in patients with elevated Troponin T (TnT) level, and NT-proBNP was significantly correlated with TnT levels. COVID-19 patients with myocardial injury are more likely to experience long-term impairment in cardiac function.
Some current investigational immunomodulatory drugs are theorized to treat symptoms of cytokine storm associated with the host inflammatory phase of the illness (see
NHE-1 is a ubiquitous transporter and is the predominant isoform in the myocardium. This isoform of the antiporter is primarily responsible for intracellular pH homeostasis and is involved in the regulation of cellular volume as well as in the regulation of inflammatory processes. It has been demonstrated in a number of inflammatory models that NHE-1 inhibition, using Sabiporide (another NHE-1 inhibitor discontinued for safety reasons) could significantly reduce nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) pathway activation, inducible nitric oxide synthase (iNOS) expression, chemokine production, leukocyte-endothelial cell interactions and attenuate neutrophil activation and infiltration (Wu et al. doi: 10.1371/journal.pone.0053932). Cariporide, another NHE-1 inhibitor, reduces the expression of Intercellular Adhesion Molecule 1 (ICAM1) and inhibits leukocyte recruitment and adhesion as well as reduces the microvascular permeability in EE2 murine endothelial cells (Qadri et al. doi: org/10.1186/s12933-014-0134-7).
Rimeporide attenuated the postischemic impairment of myocardial function through reactive oxygen species-mediated ERK1/2/Akt/GSK-38/eNOS pathways in isolated hearts from male Wistar rats. In vivo, potent anti-inflammatory activity of Rimeporide was shown in male mdx mice, a validated model of mice lacking dystrophin. Male wild-type and dystrophic mdx mice were treated for 5 weeks with vehicle, 400 part per million (ppm) Rimeporide, or 800 ppm. Rimeporide was mixed with their food starting at 3 weeks of age. At these 2 doses, plasma concentrations were ranging between 100 to 2500 nanograms per milliliter (ng/mL). Such concentrations can be achieved after oral dosing in humans and have already been shown to be safe and well tolerated. After 5 weeks of treatment, there was a significant (and clinically relevant) reduction in inflammation in both the forelimb and hindlimb muscles as measured by optical imaging (Baudy et al. doi: 10.1007/s11307-010-0376-z) of all treated groups, with maximal reduction in Cathepsin B activity observed in the 400 ppm Rimeporide treated group towards wild type levels (−26% for the forelimb and −22% for the hindlimb). See
An anti-inflammatory effect was confirmed in a clinical study with Rimeporide given orally for 4 weeks to young DMD boys (Previtali et al. doi: 10.1016/j.phrs.2020.104999). A statistically significant decrease of Monocyte Chemoattractant Protein-1/C-C Motif Chemokine Ligand 2 (MCP-1/CCL2), C-C Motif Chemokine Ligand 15 (CCL15), Tumor Necrosis Factor α (TNFα), Kallikrein 6 (KLK6), Fas Ligand (FAS) in the serum of patients receiving Rimeporide for a 4-week treatment was observed in all dose groups (see Table 1). These chemokines are involved in monocyte adhesion to endothelial cells (Park et al. doi: 10.4049/jimmunol.1202284). MCP-1/CCL2 is one of the key chemokines that regulate migration and infiltration of monocytes/macrophages. Both CCL2 and its receptor C-C Motif Chemokine Receptor 2 (CCR2) have been demonstrated to be induced and involved in various inflammatory diseases and more recently in COVID-19 patients. Migration of monocytes from the blood stream across the vascular endothelium is required for routine immunological surveillance of tissues, as well as in response to inflammation (Deshmane et al. doi: 10.1089/jir.2008.0027).
In Duchenne patients, high levels of TNFα, interferon (IFN)-γ, and interleukin (IL)-12 are observed in the blood and muscle tissues. Myofibers are attacked by inflammatory cells at the endomysial, perimysial, and perivascular areas. Furthermore, a number of cytokines can exert direct effects on the muscle tissue via the activation of signaling pathways, such as the nuclear factor NF-kB pathway, which further enhances the inflammatory response through up-regulation of cytokine/chemokine production.
Similar to DMD, a massive proinflammatory response after infection is the hallmark in severe cases of COVID-19 and contributes to disease severity and a worse prognosis (Chow et al. doi: Huang et al. 2020). In SARS-CoV-2 infected patients, retrospective analysis has demonstrated that initial plasma levels of IL-1β, IL-1RA, IL-7, IL-8, IL-10, IFN-γ, MCP-1, macrophage inflammatory protein (MIP)-1A, MIP-1B, granulocyte-colony stimulating factor (G-CSF), and TNFα are increased in patients with COVID-19 (Tufan et al. doi: 10.3906/sag-2004-168).
NHE-1 inhibitors have the potential to prevent and protect against an exuberant inflammatory response triggered by SARS-CoV-2 infection and COVID-19 without impacting the host's immune response and the viral clearance. NHE-1 inhibitors mediate the inflammatory response by preventing monocyte, macrophage and neutrophil accumulation, and the excessive release of proinflammatory cytokines. NHE-1 transporters are expressed ubiquitously and in particular in the heart, pulmonary endothelium and on lymphocyte CD4+ cells e.g., at the site of tissue injury caused by the virus. Rimeporide, a safe NHE-1 inhibitor, has the potential to specifically target the underlying mechanism of the cytokine storm observed in patients with COVID-19 that is associated with poor prognosis and worse outcomes. Rimeporide, alone or in combination with other therapeutic interventions, could efficiently and safely modulate the inflammatory response without compromising the host immune response against SARS-CoV-2.
Amiloride and its derivatives have demonstrated in vitro antiviral effects in other RNA virus infections. Holsey et al. (doi: 10.1002/jcp.1041420319) have shown that poliovirus infection (also an RNA virus) causes an increase of cytoplasmic pH which promotes virus production. EIPA inhibited both the pH rise and poliovirus production when added after virus absorption. Suzuki et al. (doi: 10.1152/ajprenal.2001.280.6.F1115) have shown that EIPA inhibits rhinovirus (HRV14) replication in human tracheal epithelial cells and decreases the number of acidic endosomes. Therefore, they concluded that its antiviral activity is due to the block of rhinovirus RNA entry from acidic endosomes to the cytoplasm. Suzuki et al. (2001) explained that like intracellular pH, endosomal pH is suggested to be regulated by ion transport across the endosomal V-ATPase and NHEs. They studied EIPA and FR-168888, inhibitors of NHEs, and bafilomycin A1, an inhibitor of Vacuolar H+ATPase (V-ATPase), which reduced pHi (intracellular pH) and increased endosomal pH. Gazina et al. (doi: 10.1016/j.antiviral.2005.05.003) confirmed the inhibition of rhinovirus release by these Amiloride derivatives and supported the idea that this stage of infection may become a target for antiviral agents. The mechanisms of the antiviral activity of amiloride derivatives are not elucidated, and according to Gazina et al. it is unlikely to be due to the inhibition of Na+ influx.
It is well known that viruses exploit and modify host-cell ion homeostasis in favor of viral infection. To that purpose, a wide range of highly pathogenic human viruses (such as SARS-CoV and MERS-CoV) encode viroporins. These are transmembrane proteins that stimulate crucial aspects of the viral life cycle through a variety of mechanisms. Noticeably, these proteins oligomerize in cell membranes to form ion conductive pores. Viroporins are involved in processes relevant for virus production. In general, these proteins do not affect viral genome replication, but stimulate other key aspects of the viral cycle such as entry, assembly, trafficking, and release of viral particles. Ion channel (IC) activity may have a great impact on host-cell ionic milieus and physiology. Once inserted on cell membranes, viroporins tune ion permeability at different organelles to stimulate a variety of viral cycle stages. As a consequence, partial or total deletion of viroporins usually leads to significant decreases in viral yields (Nieto-Torres et al. doi: 10.3390/v7072786). IC activity ranges from almost essential, to highly or moderately necessary for viruses to yield properly.
CoVs' E protein has a viroporin-like activity. They are reported to oligomerize and form ion channels. While the S protein is involved in fusion with host membranes during entry into cells, and the M protein is important in envelope formation and building, E protein is not essential for in vitro and in vivo coronavirus replication. However, its absence results in an attenuated virus, as shown for SARS-CoV. (Wilson et al. doi: 10.1016/j.virol.2006.05.028). Though the involvement of ion channels in CoVs pathogenesis is not fully understood, recently several studies have suggested that the absence of ‘SARS-CoV E’ protein results in an ‘attenuated virus’, thereby supporting that ‘SARS-CoV E’ protein is mainly responsible for pathogenesis and virulence. Interestingly, comparative sequence analysis reveals that ‘SARS-CoV E’ and ‘SARS-CoV-2 E’ protein sequences share 94.74% identity amongst themselves (Gupta et al. doi: 10.1080/07391102.2020.1751300).
Besides modifying cellular processes to favor virus propagation/pathogenicity, the loss of ion homeostasis triggered by viral ion conductivity activity may have deleterious consequences for the cell, from stress responses to apoptosis. That is why cells have evolved mechanisms to sense the ion imbalances caused by infections and elaborate immune responses to counteract viruses. Interestingly, the Ion Channel activity could trigger the activation of a macromolecular complex called the inflammasome, key in the stimulation of innate immunity. Inflammasomes control pathways essential in the resolution of viral infections. However, its disproportionate stimulation can lead to disease. In fact, disease worsening in several respiratory virus infections is associated with inflammasome-driven immunopathology.
Taking into consideration the relevance of ion channel activity in viral production, and its direct effect in pathology and disease, ion conductivity and its pathological stimulated pathways can represent targets for combined therapeutic interventions. The hexamethylene derivative of Amiloride (HMA) has been shown to block in vitro E protein ion channels and inhibit human coronavirus HCoV-229 E replication (Wilson et al. 2006). SARS-CoV-2 is an enveloped virus and E proteins present in them are reported to form ion channels which are an important trigger of immunopathology (Wilson et al. 2006; Gupta et al. 2020). HMA inhibited in vitro ion channel activity of some synthetic coronavirus E proteins (including SARS-CoV E), and also viral replication (Pervushin et al. doi: 10.1371/journal.ppat.1000511). Pervushin et al. (2009) demonstrated that HMA was found to bind inside the lumen of the ion channel, at both the C-terminal and the N-terminal openings and induced additional chemical shifts in the E protein transmembrane domain. This provides a strong rationale for ion channel activity inhibition.
Inhibiting these ion channels and regulating pH and Calcium by Rimeporide (as shown in
SARS-CoV encodes three viroproteins: Open Reading Frame (ORF) 3a, protein E, and ORF 8a. Two of these viroporins, i.e., the more dominant protein E and also ORF 3a have ion channel activity which were reported to be required for optimal viral replication. The transmembrane domain of protein E forms pentameric alpha-helical bundles that are likely responsible for the observed ion channel activity. During the course of viral infections, these viroporins oligomerize and form pores that disrupt normal physiological homeostasis in host cells and thus contribute to the viral replication and pathogenicity. Shah et al. (doi: 10.3389/fimmu.2020.01021) have shown that ion channel activity of protein E leads to the activation of the innate immune signaling receptor NLRP3 (NOD-, LRR-, and pyrin domain-containing 3) inflammasome through calcium release from intracellular stores. The activation of the inflammasome complex leads to the release of proinflammatory cytokines such as tumor necrosis factor alpha (TNFα), IL-1, and IL-6 (Castano-Rodriguez et al. doi: 10.1128/mBio.02325-14) and their accumulation promotes an exacerbated proinflammatory response, which leads to death. Due to this crucial role in triggering inflammatory response to infection, inhibition of protein E ion channel activity represents a novel drug target in the treatment of COVID-19 caused by SARS-CoV-2.
The present invention describes a structural analysis of chemical properties of various NHE-1 inhibitors' structures, their known electrostatic properties, as well as their affinity to bind inside E proteins' lumen using bio and cheminformatics approaches. Structural analysis and evaluation of chemical properties of NHE-1 inhibitors with regards to their inhibitory activities on E proteins, were performed using Chemistry and Bioinformatics approaches and tools. Based on a detailed analysis of the most eminent NHE-1 inhibitors presented in Example 1, Rimeporide is thought to have superior conformational and electrostatic properties compared to HMA and other NHE-1 inhibitors in binding the inner lumen of E proteins of SARS-CoV, and thus may provide superior efficacy in inhibiting coronaviruses replication and pathogenicity via the inhibition of protein E's ion channel activity.
Rimeporide and other NHE-1 inhibitors have the potential to improve prognosis of patients with COVID-19 by decreasing platelet activation, thereby preventing thrombosis, which contributes to a worse outcome in patients. In fact, besides mediating hemostatic functions, platelets are increasingly recognized as important players of inflammation (Mezger et al. doi: 10.3389/fimmu.2019.01731). Patients with COVID-19 often show clotting disorders, with end stage organ dysfunction and coagulopathy, thrombosis resulting in higher mortality. A dysregulated immune response, as seen in COVID-19, especially in the later stages of the disease, is known to play a decisive role in endothelial dysfunction, thrombosis and microvascular permeability seen in viral infections (Mezger et al. 2019). NHE-1 plays a large role in platelet activation. Thrombus generation involves NHE-1 activation and an increase in intracellular Ca2+, which results from NHE-1-mediated Na+ overload and the reversal of the Na+/Ca2+ exchanger. Cariporide, a potent NHE-1 inhibitor, has inhibitory effects on the degranulation of human platelets, the formation of platelet—leukocyte-aggregates, and the activation of the Glycoprotein IIb/IIIa (GPIIb/IIIa) receptor (PAC-1) (Chang et al. doi: 10.1016/j.expneurol.2014.12.023). As will be exemplified in more detail in Example 3, it is shown now by the present inventors that Rimeporide inhibits Calcium entry (see
NHE-1 plays an important role in Endothelial Cells (ECs) and inflammation as follows. NHE-1 is a ubiquitous transporter, also present in the ECs, in the heart and in the lungs, that regulates intracellular sodium, pH and indirectly calcium (Stock and Schwab. doi: 10.1111/j.1748-1716.2006.01543.x). NHE-1 is also involved in the regulation of inflammatory processes. It has been demonstrated in a number of inflammatory models that NHE-1 inhibition with Rimeporide could significantly reduce NF-kB pathway activation, iNOS expression, chemokine production, leukocyte-endothelial cell interactions, and attenuate neutrophil activation and infiltration (Wu et al. 2013). NHE-1 blockade inhibits chemokine production and NF-kB activation in immune-stimulated endothelial cells (Nemeth et al. doi: 10.1152/ajpcell.00491.2001). Monocyte chemoattractant protein-1 (MCP-1/CCL2) is one of the key chemokines that regulates migration and infiltration of monocytes/macrophages. Both MCP1 and its receptor CCR2 have been demonstrated to be induced and involved in various diseases, and to be increased in COVID-19 patients (Tufan et al. 2020). Migration of monocytes from the blood stream across the vascular endothelium is required for routine immunological surveillance of tissues, as well as in response to inflammation (Deshmane et al. 2009). MCP1, CCL15, are two chemokines known to increase adhesion of monocytes to endothelial cells (Park et al. 2013). CCL2, CCL15, KLK6 and TNFα were found to be decreased in the blood of DMD patients treated with Rimeporide after a 4-week treatment, confirming Rimeporide's anti-inflammatory biological effect in DMD boys (Previtali et al. 2020). The involvement of Rimeporide in the regulation of ECs and inflammation, without compromising the host immune response, means that Rimeporide could be safely combined with other anti-viral and immunomodulating therapies for COVID-19 patients.
NHE-1 has an important role in cardiovascular pathophysiology. Increased activity and expression of NHE-1 plays a critical role in the pathogenesis of cardiac hypertrophy, including heart failure and ischemia reperfusion injury. The role of NHE-1 in myocardial injury has been extensively studied. Ischemia causes intracellular acidification of cardiac myocytes, with reperfusion resulting in restoration of physiologic extracellular pH and creating a H+ gradient prompting efflux of H+, with concomitant Na+ influx through NHE-1. The resultant rise in intracellular Na+ then prompts an increase in intracellular Ca2+ through the Na+/Ca2+ exchange system. Finally, elevated intracellular Ca2+ triggers deleterious downstream effects, including initiation of apoptotic pathways (Lazdunski et al. doi: 10.1016/S0022-2828(85)80119-X). NHE-1 plays a critical role in cardiac hypertrophy and remodeling after injury. Indeed, cardiac-specific overexpression of NHE-1 is sufficient to induce cardiac hypertrophy and heart failure in mice (Nakamura et al. doi: 10.1161/CIRCRESAHA.108.175141). NHE-1 inhibition inhibits platelet activation and aggregation, lowering the risk of stroke (Chang et al. 2015). Rimeporide through NHE-1 inhibition, is able to decrease the cardiovascular complications, including heart failure, cardiac hypertrophy, necrosis and fibrosis, in hereditary cardiomyopathic hamsters (Chahine et al. 2005). Rimeporide through NHE-1 inhibition is able to prevent myocardial ischemia and reperfusion injury and attenuates post infarction heart failure in rat models of myocardial infarction (Karmazyn et al. doi: 10.1517/13543784.10.5.835; Gazmuri et al. doi: 10.3390/molecules24091765). NHE-1 plays a role in myocardial injury during ischemia reperfusion. In the rat model of heart failure following experimentally induced myocardial infarction (following permanent left coronary artery ligation), Rimeporide was shown to significantly and dose dependently reduce myocardial hypertrophy and preserve left ventricular function (as measured by cardiac output and left ventricular end diastolic pressure). Elevated gene expression of atrial natriuretic factor (ANP) was seen in untreated animals. ANP and its N-terminal precursor, preproANP, were decreased in the serum of treated animals in comparison with untreated animals. There was also a substantial improvement in survival in Rimeporide treated groups.
In a rat model of myocardial infarction (30 minutes coronary artery occlusion followed by 90 minutes reperfusion), Rimeporide given prophylactically (before occlusion) at doses ranging from 0.01 milligram per kilogram (mg/kg) to 1 mg/kg intravenously and 0.1 to 1 mg/kg per os (orally), was shown to reduce dose dependent infarct size. When given curatively (after the onset of ischemia and before reperfusion), Rimeporide reduced infarct size, although higher dosages in comparison to prophylactic treatment are needed to achieve a similar reduction in infarct size.
In a model of anesthetized open-chest pigs of myocardial infarction (coronary artery occlusion for 60 minutes and subsequent 4 hours reperfusion), Rimeporide was able to decrease infarct size when given before coronary occlusion at 1 mg/kg intravenously (iv) and before reperfusion at 7 mg/kg iv. NHE-1 inhibition has been known for decades as a potential treatment for myocardial ischemia.
In patients with COVID-19, there is a mismatch between oxygen supply and oxygen demand due to lung injury and patients may experience damage mimicking heart attack. Cardiac cells (including endothelial cells, cardiomyocytes and resident mast cells) respond to ischemia with release of mediators that influence myocardial performance. TNFα, IL-6, IL1, IL8 and IL2 are part of a group of negative inotropic substances leading to a cardio-depressant effect. TNFα produces deleterious effects on left ventricular performance. Myocardial ischemia also results in intracellular acidosis. With restoration of coronary blood flow (reperfusion), the myocardium recovers from acidosis, at least in part, by activation of the NHE-1. NHE-1 activation leads to an increase in intracellular Na+ concentration, known to be responsible for cardiomyocytes hypertrophy. These ion abnormalities through NHE-1 increased activity causes an intracellular Ca2+ overload secondary to the activation of the Na+/Ca2+ exchange. Intracellular Ca2+ overload during early reperfusion is thought to be involved in the long-lasting depression of contractile function (stunned myocardium) and in the development of cell necrosis (ischemia/reperfusion injury). SARS-CoV-2 not only causes viral pneumonia but has major implications for the cardiovascular system. Patients with cardiovascular risk factors (including male sex, advanced age, diabetes, hypertension and obesity) and established cardiac diseases represent a vulnerable population when suffering from COVID-19. Patients developing myocardial damage in the context of COVID-19 have an increased risk of morbidity and mortality. There is thus an urgent need to develop treatments for (1) patients with SARS-CoV-2 infection and COVID-19, (2) patients with SARS-CoV-2 infection and COVID-19 with cardiac comorbidities, (3) patients with SARS-CoV-2 infection and COVID-19 who develop myocardial injury as shown by elevated cardiac markers (Troponin or NT-proBNP or other biomarkers predictive of myocardial injury), (4) patients with heart failure and other cardiac disease pathology/complications secondary to SARS-CoV-2 infection and COVID-19, (5) patients with a vulnerable heart (preexisting underlying disease).
Diabetes (type 2 diabetes mellitus, T2DM) has been linked to increased susceptibility to and adverse outcomes associated with bacterial, mycotic, parasitic, and viral infections, attributed to a combination of dysregulated innate immunity and maladaptive inflammatory responses. Altered glucose homeostasis during a condition of severe pneumonia with SARS, are reported as main factors of worse prognosis and deaths (Yang et al. doi: 10.1111/j.1464-5491.2006.01861.x). Both insulin resistance and T2DM are associated with endothelial dysfunction, and enhanced platelet aggregation and activation. T2DM and obesity are frequent co-morbidities and a cause of worse prognosis/death in patients with COVID-19 (Guan et al. doi: 10.1056/NEJMoa2002032; Sardu et al. doi: Endothelial cell NHE-1 are activated in patients with Type 2 diabetes (Qadri et al. 2014). Excessive levels of methylglyoxal (MG: glycolysis metabolite) is encountered in diabetes and is responsible for vascular complications including hypertension, enhanced microvascular permeability, and thrombosis. In endothelial cells, pathological concentrations of MG lead to activation of serum glucocorticoid inducible kinase 1 (SGK1) and to increased NHE-1. Cariporide attenuates the proinflammatory effects of excessive MG. NHE inhibitors, such as Rimeporide, may be beneficial to prevent endothelial cell inflammation in COVID-19 patients with diabetes and hyperglycemia.
Upregulation of NHE-1 expression in whole blood of patients with COVID-19 compared with other respiratory infections at first medical contact in the emergency department was shown (Mustroph et al. doi: 10.1002/ehf2.13063). The ratio of glucose transporter 1 (GLUT1) to NHE-1 was found to be significantly decreased in the blood of COVID-19 patients with severe disease compared to patients with moderate disease. GLUT1 is a key glucose transporter in many tissues, within the heart fundamentally too, and NHE-1 and GLUT-1 expression is thought to be directly linked, in one way due to both having a role in cellular pH regulation, amongst other relationships. Moreover, there is evidence of a significantly elevated NHE-1 expression in the left ventricular myocardium of patients who died from COVID-19 compared with controls (non-infected donors). Accompanying left ventricle myocardial findings included a significantly altered GLUT1 expression and a significantly lower ratio of GLUT1 and NHE-1 in the myocardium of deceased COVID-19 patients, mirroring the ratio findings in whole blood, but with an even greater decrease (Mustroph et al. 2020). It was thus concluded by Mustroph et al. (2020) that NHE-1 and GLUT1 may be critically involved in the disease progression of SARS-CoV-2 infection and that a decreased ratio of GLUT1/NHE-1 could potentially serve as a biomarker for disease severity in patients with COVID-19. This supposes a potential role for NHE-1 modulation in patients with severe COVID-19 disease.
Acute lung Injury (ALI) is a major determining factor of the prognosis of patients with SARS-CoV-2 infection and COVID-19 disease. About 30% of patients with COVID-19 disease in Intensive Care Unit (ICU) developed severe lung edema, dyspnea, hypoxemia, or even Acute Respiratory Distress Syndrome (ARDS). Lungs have been found to express NHE-1 (Orlowski et al. doi: 10.1016/50021-9258(19)50428-8). Increased NHE-1 was observed in lung tissues from animals treated with Lipopolysaccharide (LPS). In the amiloride pretreatment (10 mg/kg Intravenous injection) group of rats, NHE-1 expression was significantly reduced and LPS induced lung injury was significantly inhibited. In line with the decrease in NHE-1 expression, there was also a decreased phosphorylated-extracellular signal-regulated kinases (p-ERK) expression in amiloride treated rats. Inhibition of NHE-1 by Amiloride was shown to have a protective effect in a murine model of Lipopolysaccharide induced acute lung injury (Zhang et al. doi: 10.1155/2018/3560234). In addition, NHE-1 is known to be activated in hypoxic rats in comparison to normoxic rats and NHE-1−/− mice are protected from hypoxia induced pulmonary artery hypertension (Walker et al. doi: 10.14814/phy2.12702). Rimeporide was shown to have an antifibrotic effect in the heart and the diaphragm when given in a preventive manner to dystrophic, mdx mice (see
Pulmonary hypertension (PH) is defined as a resting mean pulmonary artery pressure (mPAP) of 25 mmHg or above (Thenappan et al. doi: 10.1136/bmj.j5492). It is classified into 5 clinical subgroups viz. pulmonary arterial hypertension (PAH), PH due to left-sided disease, PH due to chronic lung disease, chronic thromboembolic PH (CTEPH), and PH with an unclear and/or multifactorial mechanisms (Mandras et al. doi: 10.1016/j.mayocp.2020.04.039).
PAH is idiopathic in almost half of the patients, with heritable PAH, drug and toxin induced PAH and forms caused by a host of diseases such as connective tissue disorders, certain infections (e.g., HIV) amongst others, contributing to the remaining 50% of causes (Thenappan et al. 2018). In PAH, the pulmonary vasculature is obstructed via numerous mechanisms: vasoconstriction of the pulmonary vessels causes dynamic obstruction to blood flow, adverse vascular remodeling structurally obstructs the vessels, and vascular fibrosis and stiffening reduce vessel compliance, all of which are unfavorable for cardiopulmonary functioning. With sustained untoward and/or escalating pulmonary resistance because of the obstructive vascular remodeling, the right ventricle (RV) afterload increases, leading to RV hypertrophy. Ultimately, right heart failure can prevail due to maladaptive changes such as ischemia and fibrosis. Supporting the adverse pulmonary environment in which PAH expresses itself, is the presence of abnormal cell types observed in PAH, which include vascular cells such as smooth muscle cells, endothelial cells and fibroblasts, as well as inflammatory cells (Thenappan et al. 2018).
No cure for PAH exists. Hospitalizations can be frequent and costly. At present, current PAH targeted therapies focus on vasodilation of pulmonary vessels and include prostaglandins, phosphodiesterase-5 inhibitors, endothelin receptor antagonists, and soluble guanylate cyclase stimulators, used alone or in combination. They improve functional capacity and hemodynamics, as well as reduce hospital admissions, yet the underlying hallmark of PAH pathogenic features such as vascular remodeling and fibrosis which can lead to RV failure, are not addressed by them, limiting their ability to impact mortality (Thenappan et al. 2018). Another important drawback is that treatments are expensive. The disrupted balance between ACE/ACE2 and Ang II/Ang (1-7) observed in patients with SARS-CoV-2 infection has been suggested as a potential instigator of pulmonary vascular injury and remodeling (Dai and Guang. 2020). The latter premise is partly based on the finding of an altered Ang II-ACE2-Ang (1-7) axis, swayed towards an Ang II increase, which is thought to potentially be important to the pathobiology of PAH (Sandoval et al. doi: 10.1183/13993003.02416-2019.). The possibility of vascular remodeling akin to what is seen in PAH, fosters new COVID-19 disease paradigms requiring further exploration and establishing opportunities for the examination of NHE-1 inhibitors in the management of the long-term complications of COVID-19.
A new hypothesis has been generated that theorizes that SARS-CoV-2 is a virus that can trigger an increased predisposition to developing PAH and consequent right heart failure as a long-term complication in patients who were infected with the virus and subsequently recovered (regardless of disease severity) (Suzuki et al. doi: 10.1016/j.mehy.2021.110483). This theoretical predilection is based on recent histological evaluation findings of thickened pulmonary arterial vascular walls, a defining trait of PAH, in post-mortem lung tissue of patients who died from COVID-19 (Suzuki et al. 2020). Interestingly, such pulmonary vascular remodeling lesions were not identified in SARS-CoV-1 and H1 N1 infected lung tissue. Hence, it would seem that the propensity to develop PAH long term, of the two recent coronavirus pandemics, is specific to SARS-CoV-2 and as such poses possible new therapeutic needs to prevent PAH development as a long-term complication of SARS-CoV-2 infection.
Moreover, it has been demonstrated that the SARS-CoV-2 spike protein (without the rest of the viral components) mediates cell signaling processes in lung vascular cells that could promote the development of PAH (Suresh et al. doi: 10.3390/jor1010004). In the experimental setting where recombinant SARS-CoV-2 spike protein S1 subunit was added to both cultured human pulmonary artery smooth muscle cells (PASMCs) and human pulmonary artery endothelial cells, SARS-CoV-2 spike protein elicited cell growth signaling via the MEK/extracellular signal-regulated kinase (ERK) pathway (Suzuki et al. 2020). It is conjectured that the thickening of the pulmonary vessels in patients with COVID-19, as seen in the histological samples of the 10-patient cohort described in Suzuki et al. (2020) and referenced again by Suzuki et al. (2021), could be attributed to the SARS-CoV-2 spike protein boosted cell signaling. It is further proposed by the authors that the signal-induced morphological changes of hypertrophy and/or hyperplasia of vascular smooth muscle and endothelial cells contribute to the complex cardiovascular/pulmonary outcomes seen and yet to be uncovered in patients infected with COVID-19.
Combined with findings of pulmonary vascular wall remodeling in the setting of patients infected with SARS-CoV-2, the propensity for PAH development may prove to be another long-term therapeutic challenge to face amongst the growing list of belated speculative complications in the fight against SARS-CoV-2.
Additionally, we do not as yet know the long-term effects of the various COVID-19 vaccines and the possible side effects that may arise from their use. As at early August 2021, there were 21 vaccines against SARS-CoV-2 approved by at least one country [McGill COVID19 Vaccine Tracker. https://covid19.trackvaccines.org (Accessed:13 Aug. 2021)]. Messenger RNA (mRNA), viral vector and protein subunit-based vaccines all mainly make use of the spike protein found on the surface of the SARS-CoV-2 virus to trigger an immune response and prime the body for future infection, whereas the inactivated virus vaccines rely on the spike protein in addition to the other virus components to trigger an immune response. The commonality of all remains the spike protein and given the findings of the SARS-CoV-2 spike protein mediated PAH-like changes (Suzuki et al. 2020; Suzuki et al. 2021, discussed above), there is a need to be cognizant of possible COVID-19 vaccine triggered PAH as a complication of vaccine administration.
NHE-1's contribution to PASMCs intracellular pH homeostasis and the permissive role it plays in PASMC proliferation in the context of vascular remodeling which is facilitated by NHE-1 supported alkalization of the cell, has been well described (Huetsch and Shimoda. 2015).
Data obtained by the patent applicant (See Example 5 and
To confirm the potential benefit of Rimeporide on preventing pulmonary vascular remodeling, we have now investigated (see Example 6) Rimeporide in a rat Sugen/Hypoxia (Su/Hx) model of PAH to determine its effects on modulating the disease progression of PAH. This model has applicability to the setting of SARS-CoV-2 infection and COVID-19 disease with its complications. The rationale for its relevance is explained as follows:
At present, the animal models for studying COVID-19 are limited. They include small animal models such as ferret, hamster and mouse, and larger non-human primate models of Cynomolgus macaques, African Green monkeys and Rhesus macaques, amongst a larger list (Munoz-Fontela et al. doi: 10.1038/s41586-020-2787-6; [NIH. https://opendata.ncats.nih.govicovid19/animal (Accessed: 13 Aug. 2021)]. These models have their limitations. Firstly, they are limited to the acute COVID-19 setting, secondly, severity of disease (mild, moderate, severe) can vary amongst models, with individual animal species not being able to necessarily experience all seventies and symptoms (lung and myocardial) of the disease in one species e.g. mouse model is limited to mild to moderate disease and thirdly, some animals do not possess the ACE2 receptor necessary for viral entry, requiring transgenic manipulation (e.g. mouse hACE2 transgenic model), amongst other constraints.
Significantly, no model for long COVID exists. There is a growing requirement for such a model that reflects the long-term complications of COVID-19 due to now increasing evidence that long COVID/post-acute COVID-19 syndrome is a tangible reality. Given the lack of models to investigate long COVID, the long-term complications of SAR-CoV-2 infection, as well as the long-term complications that may arise in a subject who has received a SARS-CoV-2 vaccination, we understand that the Su/Hx model we used has applicability to the setting of investigating long term COVID and can support further understanding of the post-acute COVID syndrome possible pathological changes and aid in investigation of potential treatments for long COVID.
The rat Su/Hx model of PAH used, incorporates the administration of Sugen 5416 (an inhibitor of vascular endothelial growth factor receptor), followed by a period of exposure to chronic hypoxia (10%) and subsequent to this, exposure to normoxia (See Example 6 for experimental protocol and
There is no ideal animal model for COVID-19 or long COVID. We decided to choose this one on the basis of its correlation with the pathological insult viz. the exposure to hypoxia, the key driver of the disease and pathological changes (e.g., fibrosis) seen in COVID-19. There appears to be some paralleling with the pathological consequences of the Su/Hx model and with what is seen as a part of the spectrum of pathological changes seen in acute COVID-19 disease (e.g., inflammation, pulmonary vascular changes, fibrosis) and that which is seen in long COVID (e.g., consequences of long-term inflammation). We assert this because there is growing evidence that in the setting of long-term COVID-19, sequelae such as what is seen in PAH, namely the pulmonary vascular remodeling, which is fibrotic in nature, cardiac manifestations such as myocardial injury that includes myocardial fibrosis, of which right ventricular fibrosis is included (Nalbandian et al. 2021; Dai and Guang. 2020; Suzuki et al. 2020) are being identified. Hence, we assert the Su/Hx model as a suitable proxy at this point in time for COVID-19 model application.
Key cardiopulmonary echocardiography findings in the rat Su/Hx model of PAH include a statistically significant decrease in Mean Pulmonary Arterial Pressure (mPAP) after the administration of Rimeporide following establishment of an induced PAH state, as compared to untreated Su/Hx rats (see
Other measures of importance relate to the involvement of the right ventricle (RV) and its associated compensatory mechanisms because of worsening PAH. Measures of RV wall thickness and RV internal diameter at diastole obtained through echocardiography, improve and stabilize, respectively with Rimeporide administration (see
Complementing right ventricular rehabilitation, are the findings of a stabilization and prevention of a further drop in the Pulmonary Artery Acceleration Time/Ejection Time (PA AT/ET) (an indirect measure of RV function and resistance, pulmonary resistance), and improvement in RV cardiac output, all noticed with the administration of Rimeporide (see
Several other hemodynamic parameters measured in the experiment provide evidence of Rimeporide having an impact on key measures of systolic and diastolic function (see
Researchers have noted that there is a high burden of RV dysfunction in patients with the severest forms of COVID-19, those who are critically ill with COVID-19 (Bleakley et al. doi: 10.1016/j.ijcard.2020.11.043; Bonnemain et al. doi: 10.3390/jcm10122535). The aforementioned findings suggest that Rimeporide could prove effective in mitigating the deleterious RV function outcomes and/or ameliorating RV dysfunction that occurs as result of infection with SARS-CoV-2 and its variants, especially in those patients who display the severest manifestations of COVID-19 disease.
RV/LV+S is an important measure in assessing the impact of PAH on RV hypertrophy. This was measured in a small subset of experimental animals in the Su/Hx experiment and as expected, was raised in both the Su/Hx and Su/Hx+Rime groups when compared to the normoxic groups. Although not a statistically significant finding, there was a trend towards lower RV/LV+S ratio in the Su/Hx animals who received Rimeporide when compared with the Su/Hx group who did not receive Rimeporide (see
Other improvements seen in the Su/Hx model (see
Thus, Rimeporide may be efficacious in treating a subject suffering from long COVID, presenting with long COVID, having clinical manifestations, organ effects of long COVID and displaying pathological changes and long-term complications associated with long COVID (see
Long COVID refers to the persistence of symptoms after recovery from acute COVID-19 illness. There is no internationally agreed definition of the post-acute COVID condition yet. In addition to the terminology of long COVID, others are used, which include chronic COVID syndrome, late sequelae of COVID-19, long haul COVID, long-term COVID-19, post COVID syndrome, post-acute COVID-19, post-acute sequelae of SARS-CoV-2 infection and more recently Post-acute COVID-19 Syndrome (PACS). A person is said to be suffering from PACS when they have persistent symptoms and/or delayed or long-term complications of SARS-CoV-2 infection beyond 4 weeks from the onset of symptoms (Nalbandian et al. 2021). This syndrome is further subdivided into two categories according to the length of time of symptom presentation following acute infection and/or the persistence of symptoms following the onset of acute COVID-19: Subacute/ongoing symptomatic COVID-19 is characterized by symptoms and abnormalities present from 4-12 weeks beyond acute COVID-19, whereas chronic/post COVID-19 syndrome encompasses symptoms and abnormalities persisting or present beyond 12 weeks of acute COVID-19 and where there is no alternative diagnosis. For now, the majority of long-term data reflects periods ranging 6 to 9 months post-acute SARS-CoV-2 infection. The most recent studies suggest that there are a host of long-term complications, affecting multiple organ systems, with pulmonary and cardiovascular organ system symptomatology and pathology increasingly identified.
Much has been published recently to try and elucidate what COVID-19 associated heart injury will look like in patients recovered from acute COVID-19 infection. A recent review indicated that chest pain and palpitations are common cardiac symptoms experienced by patients with PACS and concerns of myocarditis, Postural Orthostatic Tachycardia syndrome, arrhythmias, pericarditis and unmasked coronary artery disease as cardiovascular manifestations of PACS are rising (Dixit et al. doi: 10.1016/j.ahjo.2021.100025). Furthermore, evidence of myocardial tissue abnormalities on imaging are linked with inflammation in the medium term, post-acute infection with COVID-19 (Raman et al. doi: 10.1016/j.eclinm.2020.100683). There is mounting evidence of right ventricular dysfunction as a consequence of SARS-CoV-2 infection based on cardiac echo and MRI imaging findings. MRI Imaging findings across a range of studies of patients with COVID-19 infection, suggest long-term effects of COVID-19 on the heart, which include oedema, fibrosis and impaired right ventricle (RV) contractile function (Lan et al. doi: 10.3389/fcvm.2021.606318). An increased susceptibility of the RV to lung injury compared with the left ventricle, effects of ARDS on RV, effects of pulmonary embolism in COVID-19 on RV and the global effect of myocardial injury and the cytokine storm on the heart, is described by Lan et al. (2021) as some of the factors that make the RV susceptible to functional change in patients infected with SARS-CoV-2 and lead to their notion that RV damage in COVID-19 may be an association between myocardial damage and lung injury in COVID-19. Our findings in the Su/Hx model supposes that the use of Rimeporide, an NHE-1 inhibitor, could modulate RV fibrosis and pulmonary vascular remodeling, thus potentially improving RV function in those with long-term complications of COVID-19/long COVID.
There is also recent speculation of a possible causal relationship between COVID-19 mRNA vaccine administration and myocarditis and pericarditis (Das et al. doi: 10.3390/children8070607). Updates are frequently released relating to new findings of vaccine-related complications. Cases of myocarditis and pericarditis have been reported very rarely following vaccination with the COVID-19 mRNA Vaccines Comirnaty and Spikevax, with cases having primarily occurred within 14 days after vaccination, more often after the second dose and in younger men [EMA 2021; https://www.ema.europa.eu/en/docu ments/dh pc/direct-healthcare-professional-communication-dh pc-covid-19-mma-vaccines-comimaty-spikevax-risk_en.pdf (Accessed: 22 Jul. 2021)], The latter again highlights the many unknowns regarding the COVID-19 vaccines and their potential complications. Rare complications may become less rare and more prevalent as vaccine-rollout progresses and we therefore have to actively engage in the development of therapeutic strategies that may be needed to deal with these complications.
As Rimeporide has shown effects on modulating fibrosis in several animal models including the cardiomyopathic hamsters (Chahine et al. 2005) and the mdx mice (see
Post COVID Pulmonary Fibrosis (PCPF) is the term used by Ambardar and colleagues (2021) to synthesize all the varying iterations and meanings ascribed to pulmonary fibrosis that have been associated with SARS-CoV-2 infection and COVID-19 disease. It encompasses a non-idiopathic form of pulmonary fibrosis associated with COVID-19 disease, which is heterogeneous in many aspects and can present anytime from initial hospitalization to long-term follow-up (Ambardar et al. 2021). Pulmonary fibrosis is a subcategory of interstitial lung disease (ILD) as well as a pathological outcome of acute and chronic ILDs. ILD as a term incorporates a variety of diffuse parenchymal lung diseases, with an array of clinical, radiologic and pathologic features (Ambardar et al. 2021). Fibrosis itself simplistically refers to the excess deposition of extracellular matrix components such as collagen and fibronectin in and around inflamed or damaged tissue. It is a common pathological outcome of many chronic inflammatory diseases (Wynn et al. doi: 10.1038/nm.2807). As such, since we have shown an effect of Rimeporide on heart fibrosis and a link with pulmonary vascular fibrosis improvement (see
Another potential effect of Rimeporide in the pulmonary tissue, relates to its impact on the inflammatory response seen in the lungs. Macrophages are key players in the immunopathological profile of SARS-CoV-2 infection. They secrete cytokines (IL-6 and TNFα, amongst others) and orchestrate responses by other cells imperative to the immune response. Increased alveolar macrophage recruitment has been reported in the lungs of patients with COVID-19 (Wang et al. doi: 10.1016/j.ebiom.2020.102833), contributing to the dysregulated innate immune response (Rodrigues et al. doi: 10.1093/oxfimm/iqaa005), and the perpetuation of a positive feedback loop with T cells that drives ongoing alveolar inflammation in SARS-CoV-2 infection (Grant et al. doi: 10.1038/s41586-020-03148-w). These dysregulated immune responses can aggravate SARS-CoV-2 infection, assist in the development of a cytokine storm, and ultimately worsen COVID-19 disease severity and associated outcomes. Rimeporide has been shown to modulate the inflammatory response in the Su/Hx rat model. A lower infiltration of macrophages has been seen in the Su/Hx rats who received Rimeporide when compared with Su/Hx rats who did not receive Rimeporide (see
There are patients who have been identified as high risk for post-acute COVID-19 syndrome. NHE-1 inhibitors could be particularly useful in these patients. High risk patients are described by Nalbandian and colleagues (2021) to be those with: severe illness during acute COVID-19 and/or requirement for care in an ICU, advanced age, and the presence of organ comorbidities (pre-existing respiratory disease, obesity, diabetes, hypertension, chronic cardiovascular disease, chronic kidney disease, post-organ transplant or active cancer). Based on the findings of Mustroph et al. (2020) where NHE-1 overexpression is noted in patients with severe COVID-19 and a possible relationship between disease severity and NHE-1 overexpression emerging, we propose that patients with augmented NHE-1 expression be considered high risk for post-acute COVID-19 syndrome too. As such, we hypothesize that decreasing NHE-1 may lead to a beneficial outcome associated with PACS i.e., possible prevention and/or amelioration of/limiting disease progression of PACS pathology, especially pulmonary vascular remodeling and RV associated pathology.
“COVID-19” is the name of the disease which is caused by a SARS-CoV-2 infection. While care was taken to describe both the infection and disease with accurate terminology, “COVID-19” and “SARS-CoV-2 infection,” “COVID-19 pneumonia,” are meant to be roughly equivalent terms and are also intended to cover diseases caused by SARS-CoV-2 variants. The definition of SARS-CoV-2 according to this patent application encompasses all the identified and as yet unidentified variants at the time of writing this patent application.
As of the writing of this application, the determination and characteristics of the severity of COVID-19 patients/symptoms has not been definitively established. However, in the context of this invention, “mild to moderate” COVID-19 occurs when the subject presents as asymptomatic or with less severe clinical symptoms [e.g., low grade or no fever (<39.1° C.), cough, mild to moderate discomfort] with no evidence of pneumonia, and generally does not require medical attention. When “moderate to severe” infection is referred to, generally patients present with more severe clinical symptoms (e.g., fever>39.1° C., shortness of breath, persistent cough, pneumonia, etc.). As used herein “moderate to severe” infection typically requires medical intervention, including hospitalization. During the progression of disease, a subject can transition from “mild to moderate” to “moderate to severe” and back again in one course of a bout of infection.
Treatment of subjects suffering from COVID-19 using the methods of this invention include administration of an effective amount of an NHE-1 inhibitor at any stage and diagnosis point of the SARS-CoV-2 infection/COVID-19 disease in a subject (including prophylactic administration) and/or at any point during the evolution and/or presentation of its acute and long-term complications to prevent or reduce the symptoms associated therewith. Typically, subjects will be administered an effective amount of an NHE-1 inhibitor prophylactically (as part of a strategy to mitigate the severity of any disease manifestations associated with SARS-CoV-2 infection should an individual be infected and/or as part of a prophylactic strategy for patients at high-risk for post-acute COVID-19 syndrome/long COVID/long-term complications, etc., including those with elevated NHE-1 expression) and/or after definitive diagnosis and presentation with symptoms consistent with a SARS-CoV-2 infection and COVID-19 disease (acute, sub-acute or long COVID disease with acute and/or long-term complications). This administration will reduce the severity of the infection and/or prevent progression of the infection to a more severe state and/or prevent and/or ameliorate long-term effects of SARS-CoV-2 infection.
Also, treatment of subjects suffering from COVID-19 vaccine-induced complications using the methods of this invention include administration of an effective amount of an NHE-1 inhibitor at any stage of vaccine administration (pre-vaccination, concomitant around period of vaccine administration or post-vaccine administration) to prevent and/or treat vaccine-associated complications, such as vaccine-associated PAH, myocarditis, pericarditis, but not limited to these vaccine-associated complications. While care has been taken to investigate COVID-19 vaccine complications, COVID-19 vaccine roll-out and its longitudinal follow up is still in its infancy and as such vaccine complication causality versus association is not clear. For that reason, the terms vaccine-related, vaccine-induced, and vaccine-associated are meant to be roughly equivalent terms.
The clinical benefits of the above administrations are described in more detail in the sections below.
In one embodiment of the invention the NHE-1 inhibitor is Rimeporide hydrochloride or pharmaceutically acceptable salts thereof.
In another embodiment, the NHE-1 inhibitor is Cariporide or a pharmaceutically acceptable salt thereof.
In another embodiment, the NHE-1 inhibitor is Eniporide or a pharmaceutically acceptable salt thereof.
In another embodiment, the NHE-1 inhibitor is Amiloride or a pharmaceutically acceptable salt thereof.
Unless otherwise stated, inhibitors mentioned herein are also meant to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having the present structures including the replacement of hydrogen by deuterium or tritium, or the replacement of a carbon by a 13C- or 14C-enriched carbon are within the scope of this invention. In some embodiments, the group comprises one or more deuterium atoms.
The term “patient” or “subject”, as used herein, means an animal, preferably a human. However, “subject” can include companion animals such as dogs and cats. In one embodiment, the subject is an adult human patient. In another embodiment, the subject is a pediatric patient. Pediatric patients include any human which is under the age of 18 at the start of treatment. Adult patients include any human which is age 18 and above at the start of treatment. In one embodiment, the subject is a member of a high-risk group, such as being over 65 years of age, immunocompromised humans of any age, humans with chronic lung conditions (such as, asthma, COPD, cystic fibrosis, etc.), humans with cardiac chronic conditions (such as heart failure, arrythmias, myocarditis, myocardial injury, myocardial fibrosis etc.) and humans with other co-morbidities. In one aspect of this embodiment, the other co-morbidity is obesity, diabetes, and/or cardiovascular disease.
Compositions of the present invention are administered orally, parenterally, by inhalation spray, rectally, or nasally. Preferably, the compositions are administered orally. In one embodiment, the oral formulation of a compound of the invention is a tablet or capsule form. In another embodiment, the oral formulation is a solution or suspension which may be given to a subject in need thereof via mouth or nasogastric tube. Any oral formulations of the invention may be administered with or without food. In some embodiments, pharmaceutically acceptable compositions of this invention are administered without food. In other embodiments, pharmaceutically acceptable compositions of this invention are administered with food. In another embodiment, the NHE-1 inhibitor is inhaled using a drug powder inhaler.
In one embodiment, the intravenous formulation of a compound of the invention is an intravenous solution or a freeze-dried product developed for parenteral administration. In ventilated patients for whom it is not possible to administer the drug orally, a parenteral formulation of a compound of the invention could be administered intravenously as a slow-release infusion or by peritoneal route or via intramuscular injections.
Pharmaceutically acceptable compositions of this invention are orally administered in any orally acceptable dosage form. Exemplary oral dosage forms are capsules, tablets, aqueous suspensions or solutions. In the case of tablets for oral use, carriers commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried cornstarch. When aqueous suspensions are required for oral use, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening, flavoring or coloring agents are optionally also added. Pharmaceutically acceptable compositions of this invention relate to pharmaceutical compositions for the parenteral administration of the compound in the form of sterile aqueous solutions providing a good stability or a lyophilized pharmaceutical solid composition to be reconstituted to provide a solution for intravenous, intraperitoneal and intramuscular administration.
In one embodiment, the formulation of a compound of the invention is provided as slow-release formulation that allows to decrease the number of dosings per day. The amount of compounds of the present invention that are optionally combined with the carrier materials to produce a composition in a single dosage form will vary depending upon the host treated, the particular mode of administration (oral or parenteral). Preferably, provided compositions should be formulated so that a dosage of between 0.01-100 mg/kg body weight/day of the compound can be administered to a patient receiving these compositions.
In one embodiment, the total amount of NHE-1 inhibitor administered orally to the subject in need thereof is between about 50 mg to about 900 mg per day either as a single dose or as multiple doses.
In some of the above embodiments, the NHE-1 inhibitor is administered for a period of about 7 days to about 28 days.
In some of the above embodiments, the NHE-1 inhibitor is administered for a chronic period of more than 3 months due to a prolongation of the symptoms and the risks to develop severe and irreversible damages.
In one embodiment of the invention, the subject has a confirmed diagnosis of a SARS-CoV-2 infection. In one embodiment of the invention, the subject is suffering from an extreme proinflammatory response due to COVID-19, which may present in any major organ of the body. In one embodiment of this invention, the subject is suffering from acute respiratory distress syndrome (ARDS) due to COVID-19 and has elevated D Dimers or any other fibrinogen degradation products. In one embodiment of this invention, the subject is suffering from myocardial injury. In one embodiment of this invention, the subject is suffering from underlying cardiovascular disease and is predisposed to develop a severe form of COVID-19 infection. In one embodiment of this invention, the subject is suffering from one or more symptoms of chest pain, palpitations, syncope, hypertension, brady or tachy arrythmias, and/or has findings of increased cardiac Troponin T/I and/or N-terminal B-type natriuretic peptide (NT-proBNP) on investigation.
In one embodiment of the invention, the subject is suffering from long COVID which may include: presenting with long COVID symptoms, having clinical manifestations, organ effects of long COVID or displaying pathological changes or long-term complications associated with long COVID. In particular, long COVID and long-term complications may include the development of myocardial injury, and in particular myocardial fibrosis; lung injury and in particular lung fibrosis; Post COVID pulmonary fibrosis (PCPF); pulmonary hypertension, more particularly pulmonary arterial hypertension with new-onset pulmonary arterial hypertension subsequent to SARS-CoV-2 infection or the worsening of pre-existing pulmonary arterial hypertension present before SARS-CoV-2 infection and its potential consequent effects of right ventricle adaptation, right ventricle hypertrophy, in response to pulmonary artery hypertension and eventual maladaptation with right ventricle fibrosis and ultimately right ventricle failure; and kidney injury.
In another embodiment of this invention, the subject is suffering vaccine-associated/induced complications, including reduction in the development of new-onset or worsening of existing pulmonary arterial hypertension and/or pulmonary vascular remodeling with the potential consequent effects of reduction in right ventricle hypertrophy, right ventricle fibrosis, right ventricle maladaptation and ultimately reduction in right ventricle failure in response to pulmonary artery hypertension; myocarditis and pericarditis and its associated consequences e.g. myocardial fibrosis.
In one embodiment, the subject is suffering from a hyperinflammatory host immune response to a SARS-CoV-2 infection. In one aspect of this embodiment, the hyperinflammatory host immune response is associated with one or more clinical indications selected from 1) reduced levels of lymphocytes, especially natural killer (NK) cells in peripheral blood; 2) high levels of inflammatory parameters (e.g., C reactive protein [CRP], ferritin, d-dimer), and pro-inflammatory cytokines (e.g., IL-6, TNFα, IL-8, and/or IL-1 beta; 3) a deteriorating immune system demonstrated by lymphocytopenia and/or atrophy of the spleen and lymph nodes, along with reduced lymphocytes in lymphoid organs; 4) dysfunction of the lung physiology represented by lung lesions infiltrated with monocytes, macrophages, platelets and/or neutrophils, but minimal lymphocytes infiltration resulting in decreased oxygenation of the blood; 5) acute respiratory distress syndrome (ARDS); 6) vasculitis; 7) encephalitis, Guillain-Barre syndrome, and other neurologic disorders; 8) kidney dysfunction and kidney failure; 9) hypercoagulability such as arterial thromboses; and 10) or any combination of above resulting in end-organ damage and death.
In one embodiment, the subject with COVID-19 is a pediatric patient suffering from vasculitis, including Kawasaki disease (i.e., Kawasaki syndrome) and Kawasaki-like disease.
In one embodiment of the invention, the subject is being treated inpatient in a hospital setting. In another embodiment, the subject is being treated in an outpatient setting. In one aspect of the preceding embodiments, the subject may continue being administered with the NHE-1 inhibitor after being transitioned from being treated from an inpatient hospital setting to an outpatient setting.
In one embodiment, the administration of the NHE-1 inhibitor results in one or more clinical benefit. In one aspect of this embodiment, the one or more clinical benefit is selected from the group comprising: reduction of duration of a hospital stay, reduction of the duration of time in the Intensive Care Unit (ICU), reduction in the likelihood of the subject being admitted to an ICU, reduction in the rate of mortality, reduction in the likelihood of heart failure, reduction in the likelihood of myocardial injury, reduction in the likelihood of acute lung injury, reduction of the time to recovery, reduction in the cytokine production, reduction of the severity of acute respiratory distress syndrome (ARDS), reduction in the likelihood of developing ARDS, reduction of the likelihood to have thrombotic events, and reduction of the excessive inflammatory response in the subject, reduction of the long-term complications of SARS-CoV-2 infections and COVID-19 disease including myocardial injury, and in particular myocardial fibrosis, lung injury and in particular lung fibrosis, Post COVID pulmonary fibrosis (PCPF), pulmonary hypertension, more particularly pulmonary arterial hypertension, and kidney injury. In another aspect of this embodiment, the one or more clinical benefit is selected from the group comprising vaccine-protective benefits: reduction in vaccine-associated/induced complications, including reduction in the development of new-onset or worsening of existing pulmonary arterial hypertension and/or pulmonary vascular remodeling with the potential consequent effects of reduction in right ventricle hypertrophy, right ventricle fibrosis, right ventricle maladaptation and ultimately reduction in right ventricle failure in response to pulmonary artery hypertension
In one embodiment, the one or more clinical benefits includes the reduction of the inflammatory response of the subject. In one aspect of this embodiment, the reduction of the inflammatory response in the subject results in the modulation of a CD68+ cell (macrophage) mediated inflammatory response in the lungs. In one aspect of this embodiment, the reduction of the inflammatory response in the subject results in the reduction of proinflammatory cytokine release driven by NF-kB (NF-kappa-B), ERK1/2, and includes MCP1 (or CCL2), TNFα, CCL15, KLK6. In one aspect of this embodiment, the one or more clinical benefits includes the prevention or the reduction or the avoidance of a severe cytokine storm in the subject.
In a further embodiment, the one of more clinical benefits is reduction in the likelihood of being hospitalized, reduction in the likelihood of ICU admission, reduction in the likelihood being intubated (invasive mechanical ventilation), reduction in the length of hospital stay, reduction in the likelihood of irreversible comorbidities including chronic heart failure, lung injury, kidney injury, reduction in the likelihood of mortality, and/or a reduction in likelihood of relapse, including the likelihood of rehospitalization.
The invention also provides a method of treating a viral infection in a subject in need thereof comprising administering an effective amount of an NHE-1 inhibitor to the subject. An amount effective to treat or inhibit a viral infection is an amount that will cause a reduction or stabilization in one or more of the manifestations of viral infection, such as viral lesions, viral load, rate of virus production, and mortality as compared to untreated control subjects.
In one embodiment, the administration of the NHE-1 inhibitor selectively reduces the hyperinflammatory host immune response state while not interfering with the subject's appropriate innate immune response to the viral infection. In one aspect of this embodiment, the hyperinflammatory host immune response state is reduced before the subject suffers a severe cytokine storm.
One embodiment of the invention is a method of treating a coronavirus infected subject in need thereof, comprising administering an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In one aspect of this embodiment, the subject is infected with SARS-CoV-2 or any of its variants. In another aspect of this embodiment, the administration of the NHE-1 inhibitor results in the reduction or stabilization of the viral load in the subject.
In one embodiment, the NHE-1 inhibitor is administered prior to the subject developing a cytokine storm. In another embodiment, the subject has a mild to moderate SARS-CoV2 infection. In a further embodiment, the subject is asymptomatic at the start of the administration regimen. In another embodiment, the subject has had known contact with a patient who has been diagnosed with a SARS-CoV-2 infection. In an additional embodiment, the subject begins administration of the NHE-1 inhibitor prior to being formally diagnosed with COVID-19.
One embodiment is a method of treating a subject with COVID-19 in need thereof, comprising administration of an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject.
Another embodiment is a method of treating a subject who is suffering from long COVID, presenting with long COVID, having clinical manifestations, organ effects of long COVID or displaying pathological changes or long-term complications associated with long COVID, comprising administering an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In a particular aspect, long COVID includes the development of new-onset pulmonary arterial hypertension subsequent to SARS-CoV-2 infection (as a consequence of or due to increased predisposition because of SARS-CoV-2 infection) or the worsening of pre-existing pulmonary arterial hypertension present before SARS-CoV-2 infection and the potential consequent effects of right ventricle adaptation, hypertrophy, in response to pulmonary artery hypertension and eventual maladaptation with right ventricle fibrosis and ultimately right ventricle failure. In another aspect the subject suffering from long COVID has pulmonary fibrosis and the administration of the NHE-1 inhibitor improves the pulmonary fibrosis.
Another embodiment is a method of treating a subject who has received a SARS-CoV-2 vaccination, comprising administering an effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In a particular aspect, the subject suffers from SARS-CoV-2 vaccination induced complications, such as pulmonary arterial hypertension, myocarditis or pericarditis or fibrosis resulting from vaccination induced myocarditis and pericarditis. In another aspect the subject has pre-existing pulmonary arterial hypertension and the NHE-1 inhibitor is administered in order to prevent SARS-CoV-2 vaccination induced worsening of the pulmonary arterial hypertension.
Another embodiment is a method of treating a subject in need thereof comprising administering a safe and effective amount of an NHE-1 inhibitor, or a pharmaceutically acceptable salt thereof, wherein the treatment is in a prophylactic manner to prevent effects and complications of SARS-CoV-2 infection and/or to stabilize and/or reduce progression of other existing disease and pathological states in a patient infected with SARS-CoV-2, at all stages and in all forms of expression of COVID-19 disease.
The NHE-1 inhibitors can be administered at any stage and diagnosis of the SARS-CoV-2 infection/COVID-19 disease in a subject (including prophylactic administration) and/or at any point during the evolution and/or presentation of its acute and long-term complications to prevent or reduce the symptoms associated therewith. A therapeutically relevant effect relieves to some extent one or more symptoms of a disorder, or returns to normality, either partially or completely, one or more physiological or biochemical parameters associated with or causative of a disease or pathological condition. The methods of the invention can also be used to reduce the likelihood of developing a disorder or even prevent the initiation of disorders associated with COVID-19 in advance of the manifestation of mild to moderate disease, or to treat the arising and continuing symptoms of an acute infection. Treatment of mild to moderate COVID-19 is typically done in an outpatient setting. Treatment of moderate to severe COVID-19 is typically done inpatient in a hospital setting. Additionally, treatment can continue in an outpatient setting after a subject has been discharged from the hospital.
The invention furthermore describes a medicament comprising at least one NHE-1 inhibitor or a pharmaceutically acceptable salt thereof.
A “medicament” in the meaning of the invention is any agent in the field of medicine, which comprises one or more compounds of the invention or preparations thereof (e.g., a pharmaceutical composition or pharmaceutical formulation) and can be used in prophylaxis, therapy, follow-up or aftercare of patients who suffer from clinical symptoms, complications of and/or known exposure to SARS-CoV-2, COVID-19, COVID-19 vaccinations.
In all of the above embodiments, the NHE-1 inhibitor may be selected from the group consisting of Rimeporide, Cariporide, Eniporide, Amiloride or a pharmaceutically acceptable salt thereof. Preferably, the NHE-1 inhibitor is Rimeporide or a pharmaceutically acceptable salt thereof.
In various embodiments, the active ingredient may be administered alone or in combination with one or more additional therapeutic agents. A synergistic or augmented effect may be achieved by using more than one compound in the pharmaceutical composition. The active ingredients can be used either simultaneously or sequentially.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more additional therapeutic agents. In one aspect of this embodiment, the one or more additional therapeutic agents is selected from antiviral, anti-inflammatories, antibiotics, anti-coagulants, antiparasitic agent, antiplatelets and dual antiplatelet therapy, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, beta-blockers, statins and other combination cholesterol lowering agents, specific cytokine inhibitors, complement inhibitors, anti-VEGF treatments, JAK inhibitors, BTK inhibitors, immunomodulators, sphingosine-1 phosphate receptors binders, N-methyl-d-aspartate (NDMA) receptor glutamate receptor antagonists, corticosteroids, Granulocyte-macrophage colony-stimulating factor (GM-CSF), anti-GM-CSF, interferons, angiotensin receptor-neprilysin inhibitors, calcium channel blockers, vasodilators, diuretics, muscle relaxants, and antiviral medications.
In one embodiment, the NHE-1 inhibitor is administered in combination with an antiviral agent. In one aspect of this embodiment, the antiviral agent is remdesivir. In another aspect of this embodiment, the antiviral agent is lopinavir-ritonavir, alone or in combination with ribavirin and interferon-beta.
In one embodiment, the NHE-1 inhibitor is administered in combination with a broad-spectrum antibiotic.
In one embodiment, the NHE-1 inhibitor is administered in combination with chloroquine or hydroxychloroquine. In one aspect of this embodiment, the NHE-1 inhibitor is further combined with azithromycin.
In one embodiment, the NHE-1 inhibitor is administered in combination with interferon-1-beta (Rebif®).
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more additional therapeutic agents selected from hydroxychloroquine, chloroquine, ivermectin, tranexamic acid, nafamostat, virazole, ribavirin, lopinavir/ritonavir, favipiravir, arbidol, leronlimab, interferon bete-1a, interferon beta-1b, azithromycin, nitazoxanide, lovastatin, clazakizumab, adalimumab, etanercept, golimumab, infliximab, sarilumab, tocilizumab, anakinra, emapalumab, pirfenidone, belimumab, rituximab, ocrelizumab, anifrolumab, ravulizumab, eculizumab, bevacizumab, heparin, enoxaparin, apremilast, coumadin, baricitinib, ruxolitinib, acalabrutinib, dapagliflozin, ibrutinib, evobrutinib, methotrexate, leflunomide, azathioprine, sulfasalazine, mycophenolate mofetil, colchicine, fingolimod, ifenprodil, prednisone, cortisol, dexamethasone, methylprednisolone, melatonin, otilimab, ATR-002, APN-01, camostat mesylate, brilacidin, IFX-1, PAX-1-001, BXT-25, NP-120, intravenous immunoglobulin (IVIG), and solnatide.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more anti-inflammatory agent. In one aspect of this embodiment, the anti-inflammatory agent is selected from corticosteroids, steroids, COX-2 inhibitors, and non-steroidal anti-inflammatory drugs (NSAID). In one aspect of this embodiment, the anti-inflammatory agent is diclofenac, etodolac, fenoprofen, flurbiprofen, ibuprofen, indomethacin, meclofenamate, mefenamic acid, meloxicam, nabumetone, naproxen, oxaprozin, piroxicam, sulindac, tolmetin, celecoxib, prednisone, hydrocortisone, fludrocortisone, betamethasone, prednisolone, triamcinolone, methylprednisolone, dexamethasone, fluticasone, and budesonide (alone or in combination with formoterol, salmeterol, or vilanterol).
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more immune modulators, with one or more anticoagulants.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more antibiotics. In one aspect of this embodiment, the antibiotic is a broad-spectrum antibiotic. In another aspect of this embodiment, the antibiotic is a penicillin, anti-staphylococcal penicillin, cephalosporin, aminopenicillin (commonly administered with a beta lactamase inhibitor), monobactam, quinoline, aminoglycoside, lincosamide, macrolide, tetracycline, glycopeptide, antimetabolite or nitroimidazole. In a further aspect of this embodiment, the antibiotic is selected from penicillin G, oxacillin, amoxicillin, cefazolin, cephalexin, cefotetan, cefoxitin, ceftriaxone, augmentin, amoxicillin, ampicillin (plus sulbactam), piperacillin (plus tazobactam), ertapenem, ciprofloxacin, imipenem, meropenem, levofloxacin, moxifloxacin, amikacin, clindamycin, azithromycin, doxycycline, vancomycin, Bactrim, and metronidazole.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more anti-coagulants. In one aspect of this embodiment, the anti-coagulant is selected from apixaban, dabigatran, edoxaban, heparin, rivaroxaban, and warfarin.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more antiplatelet agents and/or dual antiplatelet therapy. In one aspect of this embodiment, the antiplatelet agent and/or dual antiplatelet therapy is selected from aspirin, clopidogrel, dipyridamole, prasugrel, and ticagrelor.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more ACE inhibitors. In one aspect of this embodiment, the ACE inhibitor is selected from benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril and trandolapril.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more angiotensin II receptor blockers. In one aspect of this embodiment, the angiotensin II receptor blocker is selected from azilsartan, candesartan, eprosartan, irbesartan, losartan, Olmesartan, telmisartan, and valsartan.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more beta-blockers. In one aspect of this embodiment, the beta-blocker is selected from acebutolol, atenolol, betaxolol, bisoprolol/hydrochlorothiazide, bisoprolol, metoprolol, nadolol, propranolol, and sotalol.
In another embodiment, the NHE-1 inhibitor is administered in combination with one or more alpha and beta-blocker. In one aspect of this embodiment, the alpha and beta-blocker is carvedilol or labetalol hydrochloride.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more interferons.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more angiotensin receptor-neprilysin inhibitors. In one aspect of this embodiment, the angiotensin receptor-neprilysin inhibitor is sacubitril/valsartan.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more calcium channel blockers. In one aspect of this embodiment, the calcium channel blocker is selected from amlodipine, diltiazem, felodipine, nifedipine, nimodipine, nisoldipine, and verapamil.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more vasodilators. In one aspect of this embodiment, the one or more vasodilator is selected from isosorbide dinitrate, isosorbide mononitrate, nitroglycerin, and minoxidil.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more diuretics. In one aspect of this embodiment, the one or more diuretics is selected from acetazolamide, amiloride, bumetanide, chlorothiazide, chlorthalidone, furosemide, hydrochlorothiazide, indapamide, metolazone, spironolactone, and torsemide.
In one embodiment, the NHE-1 inhibitor is administered in combination with one or more muscle relaxants. In one aspect of this embodiment, the muscle relaxant is an antispasmodic or antispastic. In another aspect of this embodiment, the one or more muscle relaxants is selected from carisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, orphenadrine, tizanidine, baclofen, dantrolene, and diazepam.
In some embodiments, the combination of a NHE-1 inhibitor with one or more additional therapeutic agents reduces the effective amount (including, but not limited to, dosage volume, dosage concentration, and/or total drug dose administered) of the NHE-1 inhibitor and/or the one or more additional therapeutic agents administered to achieve the same result as compared to the effective amount administered when the NHE-1 inhibitor or the additional therapeutic agent is administered alone. In some embodiments, the combination of an NHE-1 inhibitor with the additional therapeutic agent reduces the total duration of treatment compared to administration of the additional therapeutic agent alone. In some embodiments, the combination of an NHE-1 inhibitor with the additional therapeutic agent reduces the side effects associated with administration of the additional therapeutic agent alone. In some embodiments, the combination of an effective amount of the NHE-1 inhibitor with the additional therapeutic agent is more efficacious compared to an effective amount of the NHE-1 inhibitor or the additional therapeutic agent alone. In one embodiment, the combination of an effective amount of the NHE-1 inhibitor with the one or more additional therapeutic agent results in one or more additional clinical benefits than administration of either agent alone.
As used herein, the terms “treatment,” “treat,” and “treating” refer to reversing, alleviating, delaying the onset of, or inhibiting the progress of a viral infection, or one or more symptoms thereof, as described herein. In some embodiments, treatment is administered after one or more symptoms have developed. In other embodiments, treatment is administered in the absence of symptoms. For example, treatment is administered to a susceptible individual prior to the onset of symptoms (e.g., in light of a known exposure to an infected person and/or in light of comorbidities which are predictors for severe disease, or other susceptibility factors).
It has been shown in the literature that the activity of SARS-CoV envelope protein ion channels (SARS-CoV E protein) can be inhibited by N-hexamethylene Amiloride (HMA) but not by Amiloride (Pervushin et al. 2009). This striking variation inhibiting E protein ion channel activity is observed despite the similarities in the structures (only one substituent at C5 position is different between the two structures). The impact of chemical structures differences of various NHE-1 inhibitors on the inhibitory potential of SARS-CoV E proteins was evaluated in order to predict their ability to control SARS-CoV pathogenicity and replication by inhibition of the ion channel activity. Among others, chemical structures were drawn with ChemBioDraw Ultra program, structural evaluations and optimizations of molecular structures were performed with MM2 Molecular Mechanics and Molecular Dynamics methods as implemented within the Chem3D Pro software. Biochemical libraries such as PubChem, RCSB Protein Data Bank and ChemSpider were also used to compare the ability of various NHE-1 inhibitors to block the ion channel activity of SARS-CoV through interactions with protein E, and thus to further predict direct inhibitory activity of replication and pathogenicity.
Pyrazine ring NHE-1 inhibitors (Amiloride and HMA) were compared to phenyl ring NHE-1 inhibitors (Rimeporide, Cariporide and Eniporide) (see
To facilitate the structural comparison, the three moieties are distinguished in chemical structures for Amiloride, HMA and Rimeporide compounds: ad A carbonyl-guanidinium moiety, ad B central aromatic ring, and ad C substituents on the periphery of the aromatic cycle. These moieties or structural features are shown in
This work aimed to uncover the impact of each moiety and its various substituents of various NHE-1 inhibitors on their affinity to bind E protein lumen.
Undoubtedly the guanidinium moiety plays an important role in the activity in respect to proteins. For example, in its protonated form the guanidinium binding is further stabilized through cation-7 interactions. This moiety is also capable of directional H-bonding, and on other occasion can bind to an appropriate substrate through a salt bridge. In general, guanidinium can develop favorable interactions with numerous amino acid side chains and have the capacity to develop polyvalent interactions with proteins. For this moiety, the comparison between Amiloride, HMA and Rimeporide is straightforward as it is identical in all three structures.
For this moiety, both cycles: phenyl for Rimeporide and 1,4-pyrazine for Amiloride and HMA, are quite similar in their shape since in all cases is it is a planar, aromatic and stable six-membered ring. These properties warrant for all three structures in-plane special orientation of carbonyl-guanidinium and other peripheral substituents. Within this restriction, the variations can occur in meta-, ortho-, and para-substitution patterns. Amiloride and HMA own a pyrazine ring, where the two heterocyclic nitrogens modify the electron density on the remaining carbons of the cycle. Therefore, the carbons of pyrazine cycles are more electron-deficient than those of the phenyl ring of Rimeporide. The pyrazine ring is also more basic than phenyl in Rimeporide, nevertheless, the pyrazine is the least basic among diazine heterocycles and is clearly less basic than pyridine. It can be concluded from structural and geometrical point of view that the phenyl and pyrazine cycles are quite similar while some differences exist in their electronic structures and basicity.
There is a significant variability of the substitution pattern on the periphery of the central aromatic cycle, other than preexisting carbonyl-guanidinium moiety. It has been shown that in the context of E-proteins these substituents influence the pathogenicity and the viral replication of SARS-CoV (Pervushin et al. 2009). Close interactions were reported between the guanidinium residue located at R38 (arginine residue) with N-cyclohexamethylene cycle substituted at the C5 position of HMA deep inside the binding pocket located in the ion channel lumen in the C-terminal region of the E-protein. This contrast to the N-terminal binding site, where the guanidinium of HMA is inside the binding pocket, but the N-cyclohexamethylene is pointing away from the center of the channel. Our analysis has uncovered that the C-terminal binding site located in the vicinity of R38, is more pertinent than the N-terminal binding site to account for the observed selectivity, since only the binding at the C-terminal location allows to discriminate between the very different observed activities of Amiloride vs HMA. It appears that this large binding site can accommodate quite bulky C5 substituent such as N-cyclohexamethylene of HMA while comparatively small C5 amino substituent of Amiloride develop only reduced binding affinity. Indeed, HMA significantly reduced activity of E-proteins, while Amiloride was quasi-ineffective.
Methyl sulfone substituents (at the periphery of Rimeporide) have interesting physical and electronic properties such as dipole moments and dielectric constants which are indicative of pronounced polarity as a prerequisite for strong intermolecular interactions (Clark, et al. doi: 10.1007/s00894-008-0279-y). The electrostatic potentials on the molecular surface reveal interesting features including a-holes on the sulfur therefore opening possibilities for variety of simultaneous intermolecular electrostatic interactions at the binding site inside the ion channel lumen.
Methyl sulfone substituents at the periphery of Rimeporide are much better suited for an efficient interaction with the guanidinium of R38 residue inside the ion channel lumen of E-proteins. Indeed, by comparison HMA possesses at the same C5 position a relatively inert 7-membered ring of N-cyclohexamethylene consisting of six methylenes and one nitrogen. The methyl sulfone substituent on Rimeporide is precisely located at the same C5-position (i.e., in para position in respect to the carbonyl guanidinium) of the six-membered aromatic ring. For example, for the series of sulfone analogues of COX-1 and COX-2 inhibitors, it has been shown in the literature that sulfones do bind efficiently to the arginine residues such as R38 (Navarro et al. doi: 10.1016/j.bmc.2018.06.038). Moreover, Rimeporide possesses a second methyl sulfone attached to the adjacent carbon ring C6. This invention argues for a distinct possibility that this second sulfone could improve even further the binding at the C-terminal binding site of E proteins and thus may strongly inhibit ion channel activity of E proteins essential in SARS-CoV viral replication and virulence.
In the context of substituents in the periphery of the aromatic ring, and inspired by dramatic variation of the activity of Amiloride vs HMA described by Pervushin (Pervushin et al. 2009), other NHE-1 inhibitors, which are structurally related to Rimeporide, were also analyzed. Namely, the comparison of Cariporide and Eniporide with Rimeporide (see
In the context of this work, the goal was to explore the potential effects of various NHE-1 inhibitors on viral replication and pathogenicity via the inhibition of E proteins ion channel activity. This work has uncovered that the differences in C5 substituents have a major impact on the affinity of NHE-1 inhibitors to bind efficiently the lumen of E proteins and in particular with the C-terminal part of the protein. Among the 3 phenyl ring NHE-1 inhibitors studied (Cariporide, Eniporide and Rimeporide), Rimeporide appears as the best candidate for efficient binding inside the ion channel lumen of E protein, and for E protein ion channels activity inhibition.
Fluorescence microscopy was used to monitor resting pH levels in primary dystrophic wild type myotubes through the use of the acetoxy methyl (AM) ester probe BCECF (Life technologies). To stimulate the activity of NHE, the cells were exposed to a transient 20 mM NH4Cl pre-pulse. Effect of pretreatment with Rimeporide on the resting pH levels and induced activity of NHE was also investigated. Myotubes were loaded with the pH probe BCECF-AM (5 μM) for 20 min and allowed to de-esterify for another 20 min. Measurements were performed using non-radiometric fluorescence imaging microscopy by capturing images every 10 seconds with an excitation wavelength set at 440 nm and emission filter at 520 nm.
The effect of pretreatment with Rimeporide on the resting Na+ level was also investigated. Fluorescence microscopy was used to monitor the response of the Na+ sensitive probe SBFI (Life technologies) in dystrophic and wild type primary myotubes. Using this experimental setting, an NH4Cl pulse applied at the end of the pre-incubation step to activate NHE further had little impact on the net accumulation of 22Na+. We hypothesized that efficacious efflux mechanisms prevented 22Na+ to accumulate. Since Na+/K+-ATPase and Na+/Ca2+ exchanger (NCX) are major Na+ effluxers, these transporters were blocked with respectively 1 mM ouabain (Sigma Aldrich) and 30 μM KB-R7943 (Tocris). The combination of NH4Cl pulse and these efflux blockers resulted in the highest rate of 22Na+ accumulation in dystrophic myotubes. This condition was chosen for the time-course experiments. Pretreatment with Rimeporide (1-100 μM) resulted in a dose-dependent inhibition of 22Na+ accumulation in both normal (not shown) and dystrophic myotubes. Rimeporide at 100 μM prevented total sodium accumulation by around 40% as measured after 10 to 20 min of influx. A comparison between Rimeporide and other NHE inhibitors on 22Na+ fluxes (CAR. Cariporide; EIPA: ethyl-isopropyl amiloride, ZON: Zoniporide) showed that Rimeporide was the weakest inhibitor as compared to other NHE-1 inhibitors (Zoniporide>Cariporide, EIPA>Rimeporide).
Effect of pretreatment with Rimeporide on the resting Ca2+ level was also investigated. Incubating the myotube cultures with a calcium-free buffer containing thapsigargin and cyclopiazonic acid (CPA) caused Ca2+ store depletion and activation of store-operated channels (SOC). Then, re-addition of Ca2+ in the extracellular medium caused a massive Ca2+ entry, known as store-operated calcium entry (SOCE). This resulted in a 3-3.5-fold increase in the net 45Ca2+ accumulation compared to the basal condition in both wild type and dystrophic myotubes. The effect of Rimeporide was compared with other NHE-1 inhibitors (CAR: Cariporide; EIPA: ethyl-isopropyl amiloride; ZON: Zoniporide). Rimeporide treatment induced an inhibition of SOCE in dystrophic and wild type myotubes. The direct SOC blocker BTP-2 at 10 μM induced an almost complete inhibition of Ca2+ flux induced by such a protocol. This novel effect of Rimeporide has not been reported before and is shared with other NHE inhibitors. As observed for Na+ entry, Rimeporide was the weakest inhibitor of NHE-1 as compared to other NHE-1 inhibitors (Zoniporide>Cariporide, EIPA>Rimeporide)
The regulation of intracellular pH in pathological conditions is thought to be a benefit in patients with COVID-19 in several aspects: (1) Bkaily and Jacques (2017) have underlined the significance of myocardial necrosis, due to pH abnormalities as well as calcium and sodium imbalances in the pathophysiology of heart failure and have demonstrated the beneficial effects of NHE-1 inhibition using Rimeporide in preventing the deleterious effects of Ca2+ and Na+ overload, (2) coronavirus entry into susceptible cells is a complex process that requires the concerted action of receptor-binding and pH-dependent proteolytic processing of the S protein to promote virus-cell fusion. So, the regulation of pH mediated by NHE-1 inhibition may be beneficial both on the viral infectivity and the fatal cardiovascular events triggered by the COVID-19 pneumonia.
The regulation of intracellular Na+ in patients with COVID-19 may be beneficial to several complications of SARS-CoV-2 infections by (1) preventing platelet activation and thereby preventing thrombotic events, (2) preventing the cardiac hypertrophy seen in patients with myocarditis (3) protecting from the increased lung permeability that results from the inflammatory injury to the alveolo-capillary membrane and leading in the end to respiratory insufficiency.
The intracellular acidification, subsequent to hypoxemia, causes activation of the Na+/H+-exchange (NHE), which in turn contributes to the uptake of Na+ ions and (obligatory) water molecules. This induces the swelling of the platelets leading to an increased platelet volume and size. Larger platelets are hemodynamically more active and represent an increased risk for thrombosis. The platelet swelling assay served as a pharmacodynamic biomarker of drug activity. Platelets respond to an intracellular acid challenge by activating plasmalemmal NHE. The uptake of Na+ ions together with free water molecules causes a swelling of the platelets. To test the potential of Rimeporide, Cariporide and Eniporide of inhibiting human platelet swelling, the following experiments were performed. 500 μl of the platelet rich plasma containing 2.4×108 cells (appropriately diluted using platelet free plasma) were given into a plastic cuvette (1 cm path length), which was placed in a Hitachi U-2000 double beam spectrophotometer. Thereafter 1500 μl of the incubation buffer (±appropriately diluted compound) was added. 1 mM stock solutions of the compounds in DMSO were prepared. Thereafter an appropriate aliquot of the stock solution was diluted 100-fold in the incubation buffer. Further dilutions were made using the incubation buffer containing in addition 1% DMSO. The final buffer component concentrations were (mM): Na-propionate 90, K-propionate 15, HEPES 15, glucose 7.5, KCl 3.7, MgCl2 0.75, CaCl2 0.75, 0.75% DMSO, pH 6.6; the thrombocyte concentration was therefore 6×107 cells per milliliter (cells/ml). After the addition of the buffer the solution in the cuvette was mixed by moving a plastic cuvette mixer slowly 1 time up and down.
The change in absorbance at 680 nm was followed for 2 min 20 sec; the absorption values were collected every 10 sec. The platelet swelling induces a decrease in the absorbance. The decrease in optical density is thought to be induced by the diffusion of the undissociated form of the weak organic acid, propionic acid, into the cytoplasm of the thrombocytes, where it contributes to a decrease in the intracellular pH (pHi).
Though with a different degree of potency, all 3 NHE inhibitors exhibited a similar behavior in reducing the decrease in optical density at 680 nm which was observed in an optical swelling assay using human platelet rich plasma.
The decrease in optical density is thought to be induced by the diffusion of the undissociated form of the weak organic acid, propionic acid, into the cytoplasm of the thrombocytes, where it contributes to a decrease in the intracellular pH (pHi). The intracellular acidification causes activation of NHE, which in turn contributes to the uptake of Na+ ions and (obligatory) water molecules.
The measured optical density values (OD) were transformed into a set of linearized and normalized data which are representative of the change in absorbance by subtracting from all OD(t) values the ODt=4′-value and dividing the result by the OD-value of the starting time point
It is obvious that Eniporide is the most potent compound, with an IC50 (+SEM) of 30+/−1 nM. Rimeporide exhibits a mean IC50 of 455+/−36 nM and Cariporide inhibits the platelet swelling with an IC50-value of 166+/−22 nM.
Six phase I studies were performed to provide information on safety and tolerability, pharmacokinetics, pharmacodynamics and metabolism of Eniporide and its main metabolite in healthy subjects. Clinical studies were designed as double-blind, placebo-controlled, randomized, sequential group, single rising, intravenous dose either as a bolus or as an infusion. In patients treated with Eniporide, platelet swelling was reduced from a dose of 5 mg onwards. For 50 mg and above, total inhibition of platelet swelling was observed immediately post dosing. More than 80% inhibitory activity remained at 1.5 or 3 hours post dose for doses 100-200 mg; and 250-400 mg respectively which corresponds to the elimination half-life of Eniporide. After administration of 2 times 200 mg, as an infusion, 80% of the inhibitory activity was seen at 6 hours post first dose. No clinically relevant effect on platelet aggregation was noted up to 100 mg Eniporide and no clinically relevant effects on PT (prothrombin time) or APTT (activated partial thromboplastin time) were observed. Higher doses were not tested.
Platelet swelling was measured in 2 clinical studies (1 single oral ascending dose study and 1 multiple oral ascending dose study).
Single Oral Ascending Dose Study with Rimeporide EMD 62 204-004
The study was designed as a double-blind, placebo-controlled, oral, single rising dose study on the safety, tolerability, pharmacokinetics and pharmacodynamics of Rimeporide in healthy male volunteers. Within each dose group (from 300 to 600 mg), six subjects were randomized to receive oral treatment with Rimeporide and three with placebo.
In addition to safety and pharmacokinetic measures, platelet swelling, a pharmacodynamic marker, was measured ex vivo in blood samples collected from the subjects pre-dose and at 1, 3, 6, 12, 24 and 48 hours post-dose. Rate constants of the platelet swelling reaction were calculated for each of the samples. The plasma concentrations of Rimeporide were plotted against study time on the same figures as the rate constants for the subjects receiving Rimeporide. As an indication of inhibition of platelet swelling the rate constants measured in the post-dose blood samples were compared with the corresponding rate constants measured in the pre-dose (baseline) blood samples for individual subjects. A post-dose decrease in rate constant was consistently observed for the subjects receiving Rimeporide, no such change in rate constant was observed for subjects receiving placebo. A decrease in the rate constant was generally present at 1 hour post-dose, the first sample time point. The exception was Subject 15, in this subject the rate constant at 1 hour post-dose was similar to the pre-dose value, a decrease in the rate constant was not observed until 3 hours post-dose. The plasma concentration of Rimeporide in this subject was 159 ng·mL-1 at 1 hour post-dose and 3690 ng·mL-1 at 3 hours post-dose, the plasma concentrations of Rimeporide in the other subjects at 1 hour post-dose were in the range 2320 to 10500 ng mL-1.
In the majority of subjects the decrease in rate constant was maintained at 3 hours post-dose, plasma concentrations of Rimeporide at 3 hours post-dose were in the range 1680 to 5390 ng·mL-1. At 12 hours post-dose the rate constants were similar to Predose values, plasma concentrations of Rimeporide at 12 hours post-dose were in the range 160 to 965 ng mL-1. These results suggest that Rimeporide inhibits platelet swelling and that the lower Rimeporide plasma concentration threshold for inhibition of platelet swelling is between 965 to 1680 ng mL-1 which is within the range of plasma concentration that can be achieved safely with an oral treatment.
Platelet aggregation following the addition of 10 μM ADP to diluted platelets (240-300×103 platelets/μL) was measured ex vivo pre-dose and at 3, 24 and 48 hours post-dose.
There was no evidence of inhibition of platelet aggregation following the administration of Rimeporide or placebo at any of the time points tested. No effects of Rimeporide were observed on the PT and APTT results.
This means that Rimeporide is able to inhibit platelet swelling without compromising the coagulation parameters.
Blood samples collected from the subjects on day 3 at 2.5, 4.5, 7.5, 10.5, 12.5, and 15.5 hours following the first dose administration, day 5 pre-dose and 2.5 h post-dose, and on day 10 at 2.5, 4.5 and 7.5 hours post-dose were used for the ex vivo platelet swelling assay. Rate constants of the platelet swelling reaction were calculated for each of the samples and the inhibition of platelet swelling was calculated from these values and the subjects calibration curve.
In this study different concentrations of Rimeporide were used in the preparation of the calibration curves (1, 10, 100, 500, 1000, 5000, 10000 and 100000 nM) and a clear sigmoidal relationship between rate constant and Rimeporide concentration was demonstrated at these concentrations. Inspection of individual subject platelet swelling inhibition profiles for day 3 indicate some evidence of inhibition albeit inconsistent in 67% of subjects receiving Rimeporide, the inhibition is more noticeable following the second dose of Rimeporide. Overall, the results are difficult to interpret but there does appear to be evidence of inhibition of platelet swelling in the pm samples on day 3 which would approximately coincide with the maximum plasma concentration of Rimeporide following the pm dose administration.
Thrombosis has been shown to contribute to increased mortality in COVID-19 patients. It can lead to a pulmonary embolism (PE), which can be fatal, but also higher rates of strokes and heart attacks are observed in patients with thrombosis. This was confirmed in several retrospective studies and provides a rationale for using anticoagulant therapies to prevent thrombosis.
Rimeporide is able to efficiently reduce the swelling of platelets, thereby decreasing platelets activation without compromising the coagulation parameters.
Dysregulated immune response, as seen in COVID-19, especially in the late stages of the disease, is known to play a decisive role in endothelial dysfunction and thrombosis and microvascular permeability is crucial in viral infections (Mezger et al. 2019). The platelet swelling inhibition capacity of Rimeporide (see
To verify that Rimeporide inhibits sodium-hydrogen exchange activity (NHE-1) in rat pulmonary arterial smooth muscle cells (PASMCs), dose-response curves (10-7 to 10-4 M) measuring NHE activity and intracellular pH were performed in rat PASMCs in vitro of both Normoxic and Su/Hx pulmonary hypertension (PH) rats at varying doses of Rimeporide (10-6, 10-5, 10-4 M). NHE activity was measured using pH-sensitive dye BCECF [2′,7′-bis-(Carboxyethyl)-5-(and-6)-carboxyfluorescein]. Ethyl-isopropyl amiloride (EIPA) at 10-5 M was used as positive control.
Rimeporide inhibits NHE activity in the PASMCs in a dose-dependent manner in Su/Hx Pulmonary Hypertension rats (see
There is evidence of pulmonary vascular remodeling in COVID-19 patients (Suzuki et al. 2020), The findings of thickened pulmonary arterial vascular walls, a key pathognomonic feature of Pulmonary Arterial Hypertension, links PASMCs in disease pathology seen in SARS-CoV-2 infection and COVID-19 disease. Increased Na+/H+ exchange with an intracellular alkalization is an early event in cell proliferation. This intracellular alkalization by stimulation of Na+/H+ exchange appears to play a permissive role in the PASMC proliferation of vascular remodeling. Inhibition of NHE-1 prevents the development of hypoxia-induced vascular remodeling and pulmonary hypertension (Huetsch and Shimoda. 2015). Thus, Rimeporide through inhibiting NHE-1 activity in PASMCs and thereby ameliorating the reinforced alkalization of PASMCs and the subsequent proliferative surge could mitigate the component of PASMC proliferation inherent to the pulmonary vascular remodeling processes and further to that, curb the worsening of existing PAH and/or the development of PAH as a complication of infection with SARS-CoV-2, COVID-19 disease (and its various forms and stages) and/or as vaccine-associated complications.
In the Sugen/Hypoxia model (Su/Hx), rats were injected at about 3 weeks of life at day 0 with 20 mg/kg of Sugen5416 subcutaneously (s/c) for the Su/Hx and Su/Hx plus Rimeporide (Su/Hx+Rime) groups. The control groups were injected with equal volume of vehicle (sterile water), for the Normoxia (N) and Normoxia plus Rimeporide (N+Rime) groups. Both hypoxic groups of Su/Hx rats were exposed for 3 weeks to 10% 02 in hypoxic chambers (as described in Milano et al. doi: 10.1177/153537020222700604) that enable treatments, including drug administration and animal handling, avoiding any exposure of animals to atmospheric air, and thereafter housed under normoxic (21% 02) conditions for an additional 5 weeks following hypoxic exposure. The two normoxic groups, were maintained in normoxia for the same total period of time (8 weeks). The Su/Hx+Rime and the N+Rime groups received Rimeporide (100 mg/kg) every day in the drinking water from week 5 to week 8. Rats receiving Rimeporide were able to consume the Rimeporide containing water freely as they wished (see
At the end of the experiment, the rats in each group were compared to the other 3 groups they were not part of.
Preventive and curative action of Rimeporide on the pathophysiology of PAH and its sequelae, including, pulmonary artery remodeling, Right ventricle (RV) dysfunction (structural and functional), fibrosis (lung and myocardial) and inflammation was tested. RV dysfunction was assessed by echocardiography (echo) and invasive hemodynamic measurements. Assessment of RV and pulmonary hypertrophy as well as fibrosis and inflammation were performed by immunohistochemistry and Western blots. Three serial echos and repeated blood sampling was performed on each animal (at day 0, week 3, week 8). Invasive hemodynamic measurements were performed on day of sacrifice (week 8).
Procedures are described below:
Two-dimensional echocardiography and pulse-wave Doppler of the pulmonary outflow was performed using the Sequoia 512 (Acuson). Anesthetized (1-2% Isoflurane) rats were placed on a heating pad at 37° C. and ventilated with either room air or hypoxic atmosphere for normoxic and hypoxic groups, respectively.
For hemodynamic measurements, all rats were anaesthetized, placed over a heating platform at 37° C. and connected to a mechanical ventilator after tracheotomy (tidal volume 2.5 ml at 50 strokes/min) using a Harvard Apparatus with either room air or hypoxic gas (10% 02) for normoxic and hypoxic groups, respectively.
Arterial blood was withdrawn from the left carotid artery of thoracotomized rats in a heparinized syringe and arterial blood gas measurement was immediately performed. A blood sample was taken into heparinized tubes after euthanasia from the descending abdominal aorta for measurement of certain biomarkers using commercially available assays.
The RV was carefully separated from the left ventricle and septum (LV+S). After determination of RV and LV+S masses, RV/LV+S ratio was calculated to determine RV hypertrophy.
Right ventricle formalin-fixed sections were stained with Sirius Red for collagen deposition.
Lung tissue formalin-fixed sections was stained with Masson Trichome for collagen deposition.
6. Protein extraction and Western blot analysis:
In a subset of experimental animals, standard Western blotting analysis was performed using lung and cardiac lysates. In particular, a protein implicated in inflammation, such as Cluster of Differentiation 68 (CD68), was measured.
Mean Pulmonary Arterial Pressure (mPAP) was significantly higher in both the Su/Hx and Su/Hx+Rime group when compared individually with the N and N+Rime groups respectively at each timepoint of week 3, 5 and 8 (see
Pulmonary Artery Acceleration Time/Ejection Time (PA AT/ET) was significantly lower in both the Su/Hx and Su/Hx+Rime group when compared individually with the N and N+Rime groups respectively at each timepoint of week 3, 5 and 8 (see
RV free wall thickness was significantly higher in both the Su/Hx and Su/Hx+Rime groups when compared individually with the N and N+Rime groups respectively at each timepoint of week 3, 5 and 8 (see
RV internal diameter at diastole was significantly higher in both the Su/Hx and Su/Hx+Rime groups when compared individually with the N and N+Rime groups respectively at each timepoint of week 5 and 8 (see
RV cardiac output (CO) was significantly lower in both the Su/Hx and Su/Hx+Rime group when compared individually with the N and N+Rime groups respectively at each timepoint of week 3, 5 and 8 (see
RV systolic pressure was significantly higher in both the Su/Hx and Su/Hx+Rime group when compared individually with the N and N+Rime groups respectively at week 8 (see
RV End Diastolic Pressure (EDP) was significantly higher in the Su/Hx group when compared individually with the N and N+Rime groups respectively at week 8 (see
RV Tau was significantly higher in the Su/Hx group when compared individually with the N and N+Rime groups respectively at week 8 (see
Right Ventricle/Left Ventricle+Septum (RV/LV+S) weight ratio was significantly higher in both the Su/Hx and Su/Hx+Rime group when compared individually with the N and N+Rime groups respectively at the end of the study (week 8) (see
RV fibrosis was significantly higher in both the Su/Hx and Su/Hx+Rime groups when compared individually with the N and N+Rime groups respectively at the end of the study (week 8) (see
Masson trichome staining showed that pulmonary vascular fibrosis was significantly higher in both the Su/Hx and Su/Hx+Rime groups when compared individually with the N and N+Rime groups respectively at the end of the study (week 8) (see
Percentage of CD68+ cells relative to total nuclei present in lung tissue was significantly higher in both the Su/Hx and Su/Hx+Rime groups when compared individually with the N and N+Rime groups respectively at the end of study (week 8) (see
The pathogenic effects on the RV and pulmonary vasculature found in both Su/Hx groups (Su/Hx and Su/Hx+Rime groups) are in keeping with what is expected in the Su/Hx rat model of PAH. This data provides evidence that the administration of Rimeporide to these Su/Hx rats has positive effect in modulating the RV dysfunction and pulmonary vascular remodeling seen in this rat model of PAH. Moreover, there is evidence of lung inflammation regulation and mediation with Rimeporide in this model. This has applicability to the context of SARS-CoV-2 infection, COVID-19 disease in its various forms and manifestations, as well as associated vaccine roll-out. The reasoning for this is as follows:
Infection with SARS-CoV-2 and subsequent COVID-19 disease has been associated with myocardial and pulmonary damage in the acute and post-acute setting of the disease (Nalbandian et al. 2021; Dai and Guang. 2020; Suzuki et al. 2020; Dixit et al. 2021; Raman et al. 2021; Lan et al. 2021). Reports of myocardial damage and disease states that can contribute to the development of myocardial fibrosis and RV hypertrophy and dysfunction are increasingly being reported in the setting of long COVID and its associated complications. Pulmonary vascular remodeling has been identified in post-mortem specimens of patients having died from COVID-19, with the findings similar to that which is seen in patients with PAH. It is thus hypothesized that patients who have had COVID-19 are at an increased predisposition to the development of PAH and its subsequent consequences of RV dysfunction (Dai and Guang, 2020; Suzuki et al. 2020; Suzuki et al. 2021). Furthermore, the spike protein, a major component (either as an inherent antigenic stimulus or directed to be produced via genetic instruction as an antigenic provocation) in most COVID-19 vaccines, has been implicated in the development of and was shown to induce pulmonary vascular remodeling in patients infected with SARS-CoV-2 (Suzuki et al. 2020; Suzuki et al. 2021), and there have been reports of myocarditis and pericarditis with certain COVID-19 mRNA vaccines (Das et al. 2021; EMA 2021), adding to the indirect potential myocardial and pulmonary disease burdens associated with COVID-19 vaccination.
Much emphasis has been placed on the immune system response as a key driver in the severity of COVID-19 disease presentation and its outcomes and effects (acutely and in the long term) (Brodin. doi: 10.1038/s41591-020-01202-8). Our findings suggest a role for Rimeporide in modulating the immune response in COVID-19 as follows:
CD68 is a glycoprotein highly expressed in macrophages and other mononuclear phagocytes and is traditionally used as an immunological histochemical marker, providing insights into inflammatory responses (Chistiakov et al. doi: 10.1038/Iabinvest.2016.116). The higher macrophage infiltration in the Su/Hx rats is anticipated as part of the pathology of the Su/Hx PAH rat model. Macrophages are a key component of the inflammatory response in patients with SARS-CoV-2 infection. It has been noted that macrophages contribute to the dysregulated innate immune response seen in patients with COVID-19 (Rodrigues et al. 2020). There are reports of increased alveolar macrophage recruitment in the lungs of patients with COVID-19 (Wang et al. 2020). Macrophages express ACE2 and thus are amenable to direct infection with SARS-CoV-2. It was shown that these infected pulmonary macrophages secreted cytokines implicated in the pro-inflammatory state and possible cytokine storm (e.g., IL-6 and TNFα) seen in patients infected with SARS-CoV-2 (Wang et al. 2020). Infected macrophages have also been implicated in forming a positive feedback loop with T-cells driving ongoing alveolar inflammation in SARS-CoV-2 infection (Grant et al. 2021). This was identified by analysis of bronchoalveolar lavage fluid of patients with SARS-CoV-2 infection, which suggested that once infected with SARS-CoV-2, alveolar macrophages produce T cell chemoattractants, which then produce interferon gamma that induces inflammatory cytokine release from alveolar macrophages, with follow-on effects of further promoting T cell activation and perpetuating the inflammatory cycle in the alveoli. Thus, by dampening the CD68 macrophage response, Rimeporide, could prove useful in moderating the deleterious aspects of the inflammatory response seen in SARS-CoV-2 infection and COVID-19 disease.
Experiments in the Su/Hx rats combined with the experiments in heart failure and DMD animals add to the evidence that Rimeporide, an NHE-1 inhibitor, has the potential to address numerous aspects of the underlying pathophysiological processes seen in COVID-19, whether it be as result of acute infection or ongoing disease complications in the long run, or even as a consequence of COVID-19 vaccines.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20192749.8 | Aug 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/073429 | 8/24/2021 | WO |
