Patent Application
20210137969
An electronic version of the Sequence Listing is filed herewith, the contents of which are incorporated by reference in their entirety. The electronic file is 2.39 kilobytes in size, and titled 20-2001-US SequenceListing ST25.txt.
Stroke is the leading cause of adult long-term disability. Ischemic strokes are caused by an obstruction within a blood vessel, and account for 87% of all strokes with a 32% mortality rate. For some stroke survivors (˜90% for ischemic stroke), the injury leaves them with a serious disability. There are currently no FDA approved therapies to treat long-term disability, leaving physical therapy as their only medical treatment.
Immediately following stroke onset, the lack of oxygen and nutrients causes significant cell death, a large influx of microglia/macrophages and the activation of highly reactive astrocytes, which release pro-inflammatory cytokines and lead to further neuronal death and a clearance of cellular debris. Over time, the brain's defense mechanism is to compartmentalize the injured tissue from the surrounding tissue via an astrocytic and fibrotic scar, preventing repair in the stroke core. With time the stroke core is devoid of vessels and axons and cerebral atrophy occurs (brain shrinkage). Atrophy in the motor cortex accounts for at least a portion motor deficit in stroke patients. There are currently no therapies to prevent or treat cerebral atrophy, which is correlated with dementia, depression, and reduced motor function.
Astrocytes can both aid and obstruct stroke recovery with complete ablation of astrocytes resulting in a worse outcome after stroke. Astrocytes are able to communicate with multiple neurons via secreted and contact-mediated signals, can coordinate the development of synapses and neural circuits, yet astrocytes can limit long term repair and regeneration when a pro-inflammatory phenotype is adopted and a scar is formed.
Currently, no biomaterial has been described that can modulate the astrocyte phenotype from inflammatory to pro-regenerative. The present disclosure provides for injectable hydrogel microparticles, (e.g., “Microporous Annealed Particle” or MAP hydrogels microporous annealed particle (MAP) hydrogels) as a stroke treatment by modulation of the post-stroke astrocyte and microglia phenotypes.
The present disclosure provides, in part, biomaterials, pharmaceutical compositions, and methods for the treatment of cerebral atrophy and stroke in a subject.
One aspect of the disclosure provides for biomaterials. In some embodiments, a biomaterial can have a polymer having a hyaluronic acid backbone, wherein the polymer can be modified with at least one peptide. In some examples, the at least one peptide can be a ligand for integrin binding. In some examples, the polymer having a hyaluronic acid backbone, can be an acytlated hyaluronic acid.
In various embodiments, the biomaterials herein can have a hydrogel. In some examples, the hydrogels herein can be a microparticle annealed porous (MAP) hydrogel. In some examples, the hydrogels herein can be hydrogel microparticles. In some examples, the biomaterials herein can be formulated in a pharmaceutical composition, which can further include a pharmaceutically acceptable carrier. In some examples, the hydrogel microparticles herein can be formulated in a pharmaceutical composition, which can further include a pharmaceutically acceptable carrier suitable for injection.
One other aspect of the disclosure provides for methods of treating or preventing cerebral atrophy in a subject. In various embodiments, the methods of treating or preventing cerebral atrophy herein can include administering to the subject a therapeutically effective amount of a biomaterial as disclosed herein into the site of a cerebral lesion. In some examples, the biomaterials herein can be administered to a subject by intravenous injection, intracerebroventricular injection, intra-cisterna magna injection, intra-parenchymal injection, or a combination thereof.
Another aspect of the disclosure provides for methods of treating a stroke in a subject. The methods of treating a stroke herein can include administering a biomaterial as disclosed to a subject, wherein the subject can be having, suspected of having, or has had at least one stroke. In some examples, the type of stroke to be treated using the methods herein can be an ischemic stroke. In some examples, methods of administering a biomaterial disclosed herein to a subject having an ischemic stroke can be performed at least until 48 hours after a diagnosis of ischemic stroke.
An aspect of the disclosure provides for kits, wherein a kit can include any biomaterial disclosed herein and at least one container.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present disclosure, which can be better understood by reference to the drawing in combination with the detailed description of specific embodiments presented herein.
The death rate due to stroke is decreasing, resulting in more individuals living with stroke related disabilities. Following stroke, dying cells contribute to the large influx of highly reactive astrocytes and pro-inflammatory microglia that release cytokines and lead to a cytotoxic environment that causes further brain damage and prevents endogenous repair. Paradoxically, these same cells also activate pro-repair mechanisms that contribute to endogenous repair and brain plasticity.
The present disclosure is based, at least in part, on the development of a hyaluronic acid based microporous annealed particle (HA-MAP) hydrogel that, when injected into a brain lesion, promotes reparative astrocyte infiltration into the lesion. Such HA-MAP hydrogels may serve as an advantageous therapeutic option for stroke by providing neuroprotection of the infarcted area. Accordingly, described herein are hydrogels and methods of making such, pharmaceutical compositions comprising such hydrogels, and methods for delivering a hydrogel to a target site of interest, such as an infarct brain area, for treating a target disease such as brain ischemia following stroke.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to preferred embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alteration and further modifications of the disclosure as illustrated herein, being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
As used in the specification, articles “a” and “an” are used herein to refer to one or to more than one (i.e., at least one) of the grammatical object of the article. By way of example, “an element” means at least one element and can include more than one element.
“About” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “slightly above” or “slightly below” the endpoint without affecting the desired result. The term “about” in association with a numerical value means that the numerical value can vary plus or minus by 5% or less of the numerical value.
Throughout this specification, unless the context requires otherwise, the word “comprise” and “include” and variations (e.g., “comprises,” “comprising,” “includes,” “including”) will be understood to imply the inclusion of a stated component, feature, element, or step or group of components, features, elements or steps but not the exclusion of any other integer or step or group of integers or steps.
As used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations where interpreted in the alternative (“or”).
As used herein, the transitional phrase “consisting essentially of” (and grammatical variants) is to be interpreted as encompassing the recited materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. Thus, the term “consisting essentially of” as used herein should not be interpreted as equivalent to “comprising.”
Moreover, the present disclosure also contemplates that in some embodiments, any feature or combination of features set forth herein can be excluded or omitted. To illustrate, if the specification states that a complex comprises components A, B and C, it is specifically intended that any of A, B or C, or a combination thereof, can be omitted and disclaimed singularly or in any combination.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise-Indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if a concentration range is stated as 1% to 50%, it is intended that values such as 2% to 40%, 10% to 30%, or 1% to 3%, etc., are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this disclosure.
As used herein, “treatment,” “therapy” and/or “therapy regimen” refer to the clinical intervention made in response to a disease, disorder or physiological condition manifested by a patient or to which a patient may be susceptible. The aim of treatment includes the alleviation or prevention of symptoms, slowing or stopping the progression or worsening of a disease, disorder, or condition and/or the remission of the disease, disorder or condition.
As used herein, “prevent” or “prevention” refers to eliminating or delaying the onset of a particular disease, disorder or physiological condition, or to the reduction of the degree of severity of a particular disease, disorder or physiological condition, relative to the time and/or degree of onset or severity in the absence of intervention.
The term “effective amount” or “therapeutically effective amount” refers to an amount sufficient to effect beneficial or desirable biological and/or clinical results.
As used herein, the term “subject” and “patient” are used interchangeably herein and refer to both human and nonhuman animals. The term “nonhuman animals” of the disclosure includes all vertebrates, e.g., mammals and non-mammals, such as nonhuman primates, sheep, dog, cat, horse, cow, chickens, amphibians, reptiles, and the like. In some embodiments, the subject comprises a human. In other embodiments, the subject comprises a human in need of bone repair or bone formation.
“Microparticles” as used herein refers to particles including polymers, having relatively small dimensions including diameter, radius, height, width, depth, etc. In embodiments, for example, microparticles refer to particles having a lateral dimension (e.g. diameter) of less than or equal to equal to 1 mm. In some embodiments, microparticles refers to particles having an average or mean diameter of less than or equal to 500 less than or equal to 100 or less than or equal to 50 In some embodiments, microparticles are microspheres. In some embodiments, microparticles refer to particles having lateral dimensions selected from the range of 10 nm to 1000 preferably for some embodiments, 10 nm to 100 μm.
“Microdroplets” can be used herein refer to microparticles in the liquid phase. For example, in some embodiments, microdroplets refer to droplets having a mean or average diameter of less than or equal to 500 less than or equal to 100 or less than or equal to 50 μm. In embodiments, microdroplets refer to liquids in a suspension, for example an emulsion. In an embodiment, microdroplets refer to aqueous liquids suspended in a non-aqueous liquid. In some embodiments, microdroplets refer to particles having lateral dimensions selected from the range of 10 nm to 1000 preferably for some embodiments, 10 nm to 100 μm.
“Hydrogel” as used herein refers to an at least partially hydrophilic substance having characterized by high water absorbency. In some embodiments, hydrogel may have an at least partially hydrophilic polymer, superabsorbent polymer or biomacromolecule, for example in a network configuration. Hydrogels may be characterized as a water swollen but insoluble substance. In embodiments, for example, hydrogels may absorb water greater than or equal to 10 times the hydrogel weight, greater than or equal to 50 times the hydrogel weight or, optionally, greater than or equal to 100 times the hydrogel weight.
Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
In one aspect, the present invention provides for a biomaterials for the treatment of stroke. As used herein, “biomaterial” refers to any material suitable for in vivo applications. In certain instances herein, particular biomaterials of the disclosure may be referred to as hydrogels, hydrogel microparticles, or scaffolds. The biomaterials of the present invention comprise a polymer functionalized with, or conjugated to, a bioactive molecule binding moiety.
As used herein, “functionalized,” “functionalized with,” “conjugated,” and “conjugated to” are used interchangeably to refer to the chemical coupling, typically though covalent binding, of two or more molecules. Molecules may, for example, be copolymerized, or a moiety may be included as a substituent to a particular functional group or molecule. “Bioactive molecule” as used herein refers to a therapeutic agent for the treatment of diseases, disorders, and conditions, including those disclosed herein, and “bioactive molecule binding moiety” refers to a moiety able to reversibly bind to, or to dynamically covalently bind, a bioactive molecule.
As used herein, the term “hydrogel” refers to a broad class of polymeric materials, that may be natural or synthetic, have an affinity for an aqueous medium, and may absorb large amounts of the aqueous medium, but do not normally dissolve in the aqueous medium. Generally, a hydrogel can be formed by using at least one, or one or more types of hydrogel-forming agent, and setting or solidifying the one or more types of hydrogel-forming agent in an aqueous medium to form a three-dimensional network, wherein formation of the three-dimensional network may cause the one or more types of hydrogel-forming agent to gel so as to form the hydrogel. The term “hydrogel-forming agent”, also termed herein as “hydrogel precursor”, can refer to any chemical compound that may be used to make a hydrogel disclosed herein. The hydrogel-forming agent may comprise a physically cross-linkable polymer, a chemically cross-linkable polymer, or mixtures thereof. In some aspects, a hydrogel precursor can be a hydrogel microparticle. In some examples, a hydrogel microparticle for use herein can have a size ranging from about 10 μm to about 200 μm in diameter. In some examples, a hydrogel microparticle for use herein can have a size of about 10 μm, about 20 μm, about 40 μm, about 60 μm, about 80 μm, about 100 μm, about 120 μm, about 140 μm, about 160 m, about 180 μm, or about 200 μm in diameter.
In some embodiments, a hydrogel microparticle for use herein can have at least one polymeric material. In some examples, the polymeric material can be, a natural polymer material, a synthetic polymer material and combinations thereof. In some examples, a polymer suitable for use herein may be homopolymeric, heteropolymeric (including, but not limited to, cross-polymers or co-polymers of any co-monomer distribution), and may be linear, branched, hyperbranched, dendrimeric, or crosslinked to any extent. Examples of suitable polymers can include, but are not limited to, gelatin, methylcellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, polyethylene oxide, polyacrylamides, polyacrylic acid, polymethacrylic acid, salts of polyacrylic acid, salts of polymethacrylic acid, poly(2-hydroxyethyl methacrylate), polylactic acid, polyglycolic acid, polyvinylalcohol, polyanhydrides such as poly(methacrylic) anhydride, poly(acrylic) anhydride, polysebasic anhydride, collagen, poly(hyaluronic acid), hyaluronic acid-containing polymers and copolymers, polypeptides, dextran, dextran sulfate, chitosan, chitin, agarose gels, fibrin gels, and combinations thereof. In some aspects, a polymer suitable for use herein may be a hydrophilic polymer. In some examples, a hydrophilic polymer can be selected from the group comprising poly(ethylene glycol), polyoxazoline, polyaliphatic polyurethanes, polyether polyurethanes, polyester polyurethanes, polyethylene copolymers, polyamides, polyvinyl alcohols, poly(ethylene oxide), polypropylene oxide, polypropylene glycol, polytetramethylene oxide, polyvinyl pyrrolidone, polyacrylamide, poly(hydroxy ethyl acrylate), poly(hydroxyethyl methacrylate), or mixtures or co-polymers thereof. In some examples, a hydrogel microparticle for use herein may contain the synthetic polymer poly(ethylene glycol) (PEG).
In some embodiments, a hydrogel microparticle for use herein may contain hyaluronic acid (HA). HA is a non-sulphated glycosaminoglycan (GAG) in the extracellular matrix (ECM) of many soft connective tissues, composed of alternating units of D-glucuronic acid and N-acetyl-D-glucosamine with a molecular weight (MW) up to about 6 MDa, linked together via alternating β-1,4 and β-1,3 glycosidic bonds. In some examples, HA may be extracted from natural tissues including the connective tissue of vertebrates, from the human umbilical cord and from cocks' combs. In some examples, HA may prepared by microbiological methods to minimize the potential risk of transferring infectious agents, and to increase product uniformity, quality and availability. For use herein, HA can be crosslinked to impart stability, improve function, or both. Non-limiting methods of crosslinking HA include crosslinking by bisepoxide divinyl sulfone derivatives, and the like under alkaline conditions and by glutaraldehyde, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), biscarbodiimide multifunctional hydrazides, and the like under acidic conditions. In some aspects, a hydrogel microparticle for use herein may contain acrylated HA. One of skill in the art will understand how to introduce acrylate groups on HA. As an example, acrylate groups on HA can be introduced by synthesis of glycidyl methacrylate-HA (GMHA) conjugates, synthesis of N-3-aminopropyl methacrylamide-HA conjugates by modification of the carboxyl groups present in HA.
In some embodiments, a hydrogel microparticle can be formed from a hydrogel precursor solution. A “hydrogel precursor solution” as used herein can include concentrations of polymer from about 10 mg/mL to about 100 mg/mL. In some examples, a hydrogel precursor solution can include concentrations of polymer from about 10 mg/mL to about 100 mg/mL wherein the polymer is acrylated HA. In some aspects, a hydrogel precursor solution as used herein can further include at least one multifunctional polymer crosslinker. Suitable multifunctional polymer crosslinkers for use in the hydrogel precursor solution are known by those skilled in the art. A multifunctional crosslinker can be, for example, a bifunctional polymer crosslinker or a multifunctional polymer crosslinker terminated with a functional group that can form a covalent bond with the polymer of the hydrogel precursor solution. In some examples, bi-functional polymer crosslinkers and multifunctional polymer crosslinkers can be polyethylene glycol dithiol (PEG-DT), protease-degradable crosslinkers and multi-arm poly(ethylene glycol) terminated with thiol (e.g., 4-arm PEG terminated with thiol). In some other examples, suitable protease-degradable crosslinkers can be, matrix metalloproteinase (NMP)-degradable crosslinkers. Exemplary examples of suitable MMP-degradable crosslinking peptides for use in the hydrogel precursor solution herein can include
or
In some other aspects, a hydrogel precursor solution as used herein can include components needed to perform a FXIIIa-mediated crosslinking reaction. In some examples, one of at least two hydrogel precursor molecules can be functionalized with a lysine-bearing peptide sequence (K-peptide), whereas the other can be functionalized with a glutamine-bearing peptide sequence (Q-peptide). In some examples, a K-peptide can have a final hydrogel concentration of about 200 μM to about 300 μM. In some examples, a Q-peptide can have a final hydrogel concentration of about 200 μM to about 300 μM. As an example, but not limited to, a K-peptide can be Ac-FKGGERCG-NH2 (SEQ ID NO: 4) and Q-peptide can be Ac-NQEQVSPLGGERCG-NH2 (SEQ ID NO: 5). In an exemplary example, a hydrogel precursor solution as used herein can include acrylated HA, a K-peptide, and a Q-peptide.
In still some other aspects, a hydrogel precursor solution as used herein can further include a cell adhesion peptide. As used herein, a “cell adhesion peptide” refers to an amino acid sequence obtained from an adhesion protein to which cells bind via a receptor-ligand interaction. Varying the cell adhesion peptide and concentrations thereof in the solution can allow for the ability to control the stability of the cellular attachment to the resulting hydrogel composition. In some aspects, at a cell adhesion peptide can have a final hydrogel concentration of about 1 μM to about 500 μM. In some examples, a “cell adhesion peptide” can be a peptide ligand for integrin binding. Suitable peptide ligands for integrin binding include, for example, RGD, RGDS (SEQ ID NO: 6), CRGDS (SEQ ID NO: 7), CRGDSP (SEQ ID NO: 8), PHSRN (SEQ ID NO: 9), GWGGRGDSP (SEQ ID NO: 10), RGDSPGERCG (SEQ ID NO: 11). In some aspects, at a peptide ligand for integrin binding can have a final hydrogel concentration of about 1 μM to about 500 μM.
In some embodiments, a hydrogel precursor solution can be used to generate a hydrogel microparticle as disclosed herein. One of skill in the art will appreciate the methods known to generate hydrogel microparticles. Non-limiting examples of suitable methods can include bulk aqueous phase emulsification via sonication, vortexing, or homogenization, or by microfluidic drop-wise emulsification. In some exemplary examples, hydrogel microparticles can be formed by subjecting a hydrogel precursor solution as disclosed herein to a droplet generator flow focusing microfluidic device.
In some embodiments, hydrogel microparticles generated from a hydrogel precursor solution disclosed herein can be used to generate a hydrogel. In some aspects, hydrogel microparticles as described herein can be cross-linked to each to generate a hydrogel. In some aspects, hydrogel microparticles as described herein can be cross-linked to each other using the coagulation enzyme factor XIIIa (FXIIIa) to generate a hydrogel.
In some aspects, a hydrogel generated from the hydrogel microparticles disclosed herein can have a Young's modulus of about 0.5 to about 2000 Pa. In some aspects, a hydrogel generated from the hydrogel microparticles disclosed herein can have a Young's modulus of about 0.5 Pa, about 10 Pa, about 50 Pa, about 100 Pa, about 200 Pa, about 300 Pa, about 400 Pa, about 500 Pa, about 600 Pa, about 700 Pa, about 800 Pa, about 900 Pa, about 1000 Pa, about 1250 Pa, about 1500 Pa, about 1750, or about 2000 Pa.
In some aspects, a hydrogel described herein can be porous. In some examples, the pores can be homogenously dispersed throughout the hydrogel. In some other examples, the pours can be heterogeneously dispersed throughout the hydrogel. In some examples, hydrogels described herein can have micron-sized pores. In some examples, hydrogels described herein can have pores having an approximate diameter of about 0.1 μm to about 900 μm, about 1 μm to about 500 μm, or about 10 μm to about 250 μm.
Exemplary examples of a hydrogel generated from the hydrogel microparticles disclosed herein can Microporous Annealed Particle (MAP) scaffolds. MAP scaffolds can be generated from a hydrogel precursor solution disclosed herein having about 7% (w/v) to about 9% (w/v) acrylated HA. A MAP scaffold generated as described herein can have about 3% (w/v) to about 4.5% (w/v) acrylated HA. A MAP scaffold generated as described herein can have up to about 500 μM of a peptide ligand for integrin binding. A MAP scaffold generated as described herein can have a Young's modulus of about 920 Pa to about 930 Pa. A MAP scaffold generated as described herein can have pores having an approximate diameter of about 0.1 μm to about 900 μm wherein the pores can be either homogenously or heterogeneously dispersed throughout the scaffold.
Any of the biomaterials disclosed herein may be formulated to form a pharmaceutical composition, which further comprises a pharmaceutically acceptable carrier, diluent or excipient. Any of the pharmaceutical compositions to be used in the present methods can comprise pharmaceutically acceptable carriers, excipients, or stabilizers in the form of lyophilized formations or aqueous solutions.
The carrier in the pharmaceutical composition must be “acceptable” in the sense that it is compatible with the active ingredient of the composition, and preferably, capable of stabilizing the active ingredient and not deleterious to the subject to be treated. For example, “pharmaceutically acceptable” may refer to molecular entities and other ingredients of compositions comprising such that are physiologically tolerable and do not typically produce untoward reactions when administered to a mammal (e.g., a human). In some examples, the “pharmaceutically acceptable” carrier used in the pharmaceutical compositions disclosed herein may be those approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in mammals, and more particularly in humans.
Pharmaceutically acceptable carriers, including buffers, are well known in the art, and may comprise phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives; low molecular weight polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; amino acids; hydrophobic polymers; monosaccharides; disaccharides; and other carbohydrates; metal complexes; and/or non-ionic surfactants. See, e.g. Remington: The Science and Practice of Pharmacy 20th Ed. (2000) Lippincott Williams and Wilkins, Ed. K. E. Hoover.
In some embodiments, the pharmaceutical compositions or formulations are for parenteral administration, such as intravenous, intracerebroventricular injection, intra-cisterna magna injection, intra-parenchymal injection, or a combination thereof. Such pharmaceutically acceptable carriers can be sterile liquids, such as water and oil, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, and the like. Saline solutions and aqueous dextrose, polyethylene glycol (PEG) and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Pharmaceutical compositions disclosed herein may further comprise additional ingredients, for example preservatives, buffers, tonicity agents, antioxidants and stabilizers, nonionic wetting or clarifying agents, viscosity-increasing agents, and the like. The pharmaceutical compositions described herein can be packaged in single unit dosages or in multidosage forms.
Formulations suitable for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. Aqueous solutions may be suitably buffered (preferably to a pH of from 3 to 9). The preparation of suitable parenteral formulations under sterile conditions is readily accomplished by standard pharmaceutical techniques well known to those skilled in the art.
The pharmaceutical compositions to be used for in vivo administration should be sterile. This is readily accomplished by, for example, filtration through sterile filtration membranes. Sterile injectable solutions are generally prepared by incorporating biomaterials in the required amount in the appropriate solvent with various other ingredients enumerated above, as required, followed by filter sterilization. Generally, dispersions are prepared by incorporating the sterilized active ingredient into a sterile vehicle which contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and the freeze drying technique that yield a powder of the active ingredient plus any additional desired ingredient from the previously sterile-filtered solution thereof.
The pharmaceutical compositions disclosed herein may also comprise other ingredients such as diluents and adjuvants. Acceptable carriers, diluents and adjuvants are nontoxic to recipients and are preferably inert at the dosages and concentrations employed, and include buffers such as phosphate, citrate, or other organic acids; antioxidants such as ascorbic acid; low molecular weight polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as Tween, pluronics or polyethylene glycols.
Any of the biomaterials (e.g., hydrogel microparticles, hydrogels, and MAP scaffolds) described herein can be used for alleviating and/or treating stroke. Thus, in some aspects, the present disclosure provides methods for alleviating one or more symptoms and/or for treating stroke in a subject in need of the treatment biomaterials disclosed herein, as well as a pharmaceutical composition comprising such.
To perform the method disclosed herein, a therapeutically effective amount of the biomaterials or a pharmaceutical composition comprising such may be administered to a subject who needs treatment via a suitable route (e.g., intravenous, intracerebroventricular injection, intra-cisterna magna injection, or intra-parenchymal injection) at a suitable amount as disclosed herein.
As used herein, the term “treating” refers to the application or administration of a composition including one or more active agents to a subject, who is in need of the treatment, for example, having a target disease or disorder, a symptom of the disease/disorder, or a predisposition toward the disease/disorder, with the purpose to cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve, or affect the disorder, the symptom of the disease, or the predisposition toward the disease or disorder.
To perform the method disclosed herein, a therapeutically effective amount of the biomaterials or a pharmaceutical composition comprising such may be administered into at least one site of a cerebral lesion. As used herein, a cerebral lesion can be any damage to an area of brain tissue caused by injury, disease, surgery, tumor, stroke, or infection. In some examples, a cerebral lesion can be any damage to an area of brain tissue caused by ischemic stroke.
Alleviating a target disease/disorder includes delaying the development or progression of the disease, or reducing disease severity. Alleviating the disease does not necessarily require curative results. As used therein, “delaying” the development of a target disease or disorder means to defer, hinder, slow, retard, stabilize, and/or postpone progression of the disease. This delay can be of varying lengths of time, depending on the history of the disease and/or individuals being treated. A method that “delays” or alleviates the development of a disease, or delays the onset of the disease, is a method that reduces probability of developing one or more symptoms of the disease in a given time frame and/or reduces extent of the symptoms in a given time frame, when compared to not using the method. Such comparisons are typically based on clinical studies, using a number of subjects sufficient to give a statistically significant result.
“Development” or “progression” of a disease means initial manifestations and/or ensuing progression of the disease. Development of the disease can be detectable and assessed using standard clinical techniques as well known in the art. However, development also refers to progression that may be undetectable. For purpose of this disclosure, development or progression refers to the biological course of the symptoms. “Development” includes occurrence, recurrence, and onset. As used herein “onset” or “occurrence” of a target disease or disorder includes initial onset and/or recurrence.
A subject to be treated by any of the methods disclosed herein may be a human patient having, suspected of having, or has previously had a stroke. Such subjects can identified by routine medical examination, e.g., laboratory tests, organ functional tests, behavioral tests, CT scans, electroencephalogram, and/or magnetic resonance imaging (MRI). In some aspects, a subject can be a human patient having, suspected of having, or has previously had an ischemic stroke, a hemorrhagic stroke, a cryptogenic stroke, a brain stem stroke, a transient ischemic attack, or a combination thereof. In some examples, a patient to be to be treated by any of the methods disclosed herein may be having, suspected of having, or has previously had an ischemic stroke. In some examples, methods disclosed should encompass administering a composition disclosed herein within at least 48 hours after a patient has been diagnosed with ischemic stroke. In some examples, methods disclosed should encompass administering a composition disclosed herein within at least 12 hours after a patient has been diagnosed with ischemic stroke.
In any of the methods disclosed herein, an effective amount of biomaterials disclosed herein can be given to a stroke patient to alleviate one or more symptoms associated with stroke. “An effective amount” as used herein refers to a dose of biomaterials, which is sufficient to confer a therapeutic effect on a subject having stroke. In some instances, symptoms associated with stroke may be behavioral, cognitive neurorehabilitation, or a combination thereof. In some examples, symptoms of stroke to be treated by methods herein can be anxiety-related and perseverative behaviors, social behaviors, learning, memory, or a combination thereof.
Such amounts will depend, of course, on the particular condition being treated, the severity of the condition, the individual patient parameters including age, physical condition, size, gender and weight, the duration of the treatment, the nature of concurrent therapy (if any), the specific route of administration and like factors within the knowledge and expertise of the health practitioner. Effective amounts can also vary, depending on phenotypic variability among subjects having stroke, and/or the genetic mutations involved. Such an amounts can be determined by those skilled in the art following routine practice, for example, examining blood levels of virus at multiple time points after administration to determine whether the dose is proper.
Conventional methods, known to those of ordinary skill in the art of medicine, can be used to administer the biomaterial-containing pharmaceutical composition to a stroke subject. For example, this pharmaceutical composition can also be administered parenterally, e.g., by intravenous injection, intracerebroventricular injection, intra-cisterna magna injection, intra-parenchymal injection, or a combination thereof. In some embodiments, biomaterial-containing pharmaceutical compositions can administered to the human patient via at least two administration routes. In some examples, the combination of administration routes by be intracerebroventricular injection and intravenous injection; intrathecal injection and intravenous injection; intra-cisterna magna injection and intravenous injection; and intra-parenchymal injection and intravenous injection.
In some embodiments, the subject to be treated by the method described herein may be a human patient who has undergone or is subjecting to a stroke therapy. The prior stroke therapy may be complete. Alternatively, the stroke therapy may be still ongoing. In other embodiments, the stroke patient may be subject to a combined therapy involving the biomaterial therapy disclosed herein and a second stroke therapy. Stroke therapies include, but are not limited to, IV injection of recombinant tissue plasminogen activator (tPA), endovascular therapy, clot removal by surgical intervention, carotid endarterectomy, angioplasty, surgical clipping, endovascular embolization, surgical AVM removal, stereotactic radiosurgery, or a combination thereof. Additional useful agents and therapies can be found in Physician's Desk Reference, 59.sup.th edition, (2005), Thomson P D R, Montvale N.J.; Gennaro et al., Eds. Remington's The Science and Practice of Pharmacy 20.sup.th edition, (2000), Lippincott Williams and Wilkins, Baltimore Md.; Braunwald et al., Eds. Harrison's Principles of Internal Medicine, 15.sup.th edition, (2001), McGraw Hill, NY; Berkow et al., Eds. The Merck Manual of Diagnosis and Therapy, (1992), Merck Research Laboratories, Rahway N.J.
In some embodiments, the dosage of biomaterial or a pharmacological composition thereof may be adjusted based on the patient's response to the treatment. For example, if the patient shows worsening of one or more behavior features (e.g., behavioral and/or cognitive activities), the dose of biomaterials can be reduced. Alternatively, if the patient does not show clear improvement of stroke symptoms, the dose of biomaterials may be increased.
In some embodiments, the dosage of biomaterials (e.g., hydrogel microparticles, hydrogels, MAP scaffolds) or a pharmacological compositions thereof may improve astrocyte infiltration into an area of the brain infarcted following stroke. In some aspects, the dosage of biomaterials or a pharmacological compositions thereof may increase astrocyte infiltration into an area of the brain infarcted following stroke by about 10% to about 99%.
In some embodiments, the dosage of biomaterials or a pharmacological compositions thereof may improve the scar thickness in an area of the brain infarcted following stroke. In some aspects, the dosage of biomaterials or a pharmacological compositions thereof may decrease scar thickness in area of the brain infarcted following stroke by about 10% to about 99%.
In some embodiments, the dosage of biomaterials or a pharmacological compositions thereof may reduce the number of microphage/microglia in the peri-infarct and infarct spaces following stroke in a subject. In some aspects, the dosage of biomaterials or a pharmacological compositions thereof may reduce the number of microphage/microglia in the peri-infarct and infarct spaces following stroke in a subject by about 10% to about 99%.
The present disclosure also provides kits for use in treating stroke as described herein. A kit for therapeutic use as described herein may include one or more containers further including a biomaterial (e.g., hydrogel microparticles, hydrogels, or MAP scaffolds) as described herein, formulated in a pharmaceutical composition.
In some embodiments, the kit can additionally comprise instructions for use of biomaterials in any of the methods described herein. The included instructions may comprise a description of administration of the biomaterials or a pharmaceutical composition comprising such to a subject to achieve the intended activity in a subject. The kit may further comprise a description of selecting a subject suitable for treatment based on identifying whether the subject is in need of the treatment. In some embodiments, the instructions comprise a description of administering the biomaterials or the pharmaceutical composition comprising such to a subject who has or is suspected of having stroke
The instructions relating to the use of the biomaterials as described herein generally include information as to dosage, dosing schedule, and route of administration for the intended treatment. In some embodiments, the instructions comprise a description of optimizing the dose of biomaterials in a subject having stroke using one or more of the behavior features a biomarker.
The containers may be unit doses, bulk packages (e.g., multi-dose packages) or sub-unit doses. Instructions supplied in the kits of the disclosure are typically written instructions on a label or package insert. The label or package insert indicates that the pharmaceutical compositions are used for treating, delaying the onset, and/or alleviating a disease or disorder in a subject.
The kits provided herein are in suitable packaging. Suitable packaging includes, but is not limited to, vials, bottles, jars, flexible packaging, and the like. Also contemplated are packages for use in combination with a specific device, such as an inhaler, nasal administration device, or an infusion device. A kit may have a sterile access port (for example, the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). The container may also have a sterile access port.
Kits optionally may provide additional components such as buffers and interpretive information. Normally, the kit comprises a container and a label or package insert(s) on or associated with the container. In some embodiment, the disclosure provides articles of manufacture comprising contents of the kits described above.
In some embodiments, the kit include hydrogel microparticles and FXIII for injection into the stroke cavity. In some examples, the kit can contain syringes pre-loaded with hydrogel microparticles and/or FXIII and instructions for how to administer the compositions according to methods as described herein.
While the present disclosure has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the disclosure. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit, and scope of the present disclosure. All such modifications are intended to be within the scope of the disclosure.
Granular hydrogels for the Examples described herein were materials generated from hydrogel microparticle (HMP) building blocks using a droplet generator flow focusing microfluidic device (
The 4.5% microgels used in the Examples herein were produced in the same manner, however, the HA-acrylate precursor solution was dissolved at 9% (w/v). The HA without RGD microgels used in the Examples herein were produced with the same precursor solution as the 3.5% HA, however, no RGD was added. The PEG microgels used in the Examples herein were produced in a similar manner where 4-arm PEG-Vinyl sulfone was dissolved at 10% (w/v) and the peptide concentrations were the same as the HA solutions.
Nanoporous hydrogel precursor solutions were exactly the same as the microgel precursor solutions. Additionally, the same enzyme sensitive di-thiol cross-linker solution was prepared. These two solutions were thoroughly mixed in an Eppendorf tube by vortexing and pipetting. Five U/mL of FXIII and 1 U/mL of Thrombin were added to the solution and the nanoporous hydrogel was allowed to gel in situ via the same Michael type addition in which the microgels were individually formed.
HMPs were cross-linked to each other using the coagulation enzyme factor XIIIa (FXIIIa) to generate a stable scaffold, with a Young's Modulus of ˜927 Pa (
The resulting linked HMP hydrogels were termed Microporous Annealed Particle (MAP) scaffolds.
To model ischemic stroke, Examples described herein used a photothrombotic (PT) stroke model. This model allowed examination of the brain tissue's response at short term (5-15 days post stroke) and long-term time points. In brief, a cortical photothrombotic stroke was induced on 8-12 week old, male C57BL/6 mice. The mice were anesthetized with 2.5% isoflurane and placed onto a stereotactic setup. The mice were kept at 2.5% isoflurane in N2O:O2 for the duration of the surgery. A midline incision was made and Rose Bengal (4,5,6,7-tetrachloro-2′,4′,5′,7′-tetraiodafluorescein) (10 mg/mL) was injected intraperitoneally into the mouse at 10 μL/g of mouse body weight. After 5 minutes of Rose Bengal injection, a 2-mm diameter cold fiberoptic light source was centered at 0 mm anterior/1.5 mm lateral left of the bregma for 18 minutes and a burr hole was drilled through the skull in the same location. All mice were given sulfamethoxazole and trimethoprim oral suspension (TMS (303 mL TMS/250 mL H2O)) every 5 days for the entire length of the experiment.
Five days following stroke surgery, microgels with FXIII were loaded into a Hamilton syringe connected to a pump and 6 μL of microgels were injected into the stroke cavity using a 30-gauge needle at stereotaxic coordinates 0.26 mm anterior/posterior (AP), 3 mm medial/lateral (ML), and 1 mm dorsal/ventral (DV) with an infusion speed of 1 μL/min (
To assess the inflammatory response the in photothrombotic stroke model over time, mice were sacrificed via transcardial perfusion of 0.1 M PBS followed by 40 mL of 4 (w/v) % PFA seven days, fifteen days, thirty days, and one hundred twenty days following stroke as induced as described in Example 2 herein. After sacrifice, the brains were isolated and post-fixed in 4% PFA overnight and submerged in 30 (w/v) % sucrose solution for 24 hours. Tangential cortical sections of 30 μm-thickness were sliced using a cryostat and directly mounted on gelatin-subbed glass slides for immunohistological staining of GFAP (glial fibrillary acidic protein), a marker for astrocytes; IBA-1 (ionized calcium binding adaptor molecule), a marker for microglial cells; Glut-1 (Glucose Transporter-1), a marker for endothelial cells; NF200 (Neurofilament 200), a marker for axonal processes; pERK (phosphorylated extracellular signal-regulated kinase), a marker for highly reactive astrocytes; S100β (calcium-binding protein β), a marker for highly reactive astrocytes; CD11b (cluster of differentiation molecule 11B), a marker for immune cells; Arginase 1, a marker for Pro-repair microglia/macrophages; NOS2 ((Nitric Oxide Synthase 2), a marker for pro-inflammatory microglia/macrophages; Sox2 (SRY-Box Transcription Factor 2), a marker for neural progenitor cells; and DAPI (4′,6-diamidino-2-phenylindole) a marker for nuclei. Primary antibodies (1:100) or DAPI (1:500) were incubated overnight at 4° C. and secondary antibodies (1:1000) were incubated at room temperature for two hours. A Nikon C2 confocal microscope was used to take fluorescent images. The IBA-1, GFAP, pERK, 510013, CD11b, Arg1, iNOS, NF200, and Glut-1 astrocytic (GFAP) and positive area in the infarct and peri-infarct areas were quantified in 4 to 8 randomly chosen regions of interest (ROI of 0.3 mm2) at a maximum distance of 300 μm from the infarct for the peri-infarct analysis. In each ROI, the positive area was measured.
Time course analysis of macrophage/microglia (IBA1+ cells) and astrocytes (GFAP+ cells) in the infarct and peri-infarct spaces revealed an early peak (7-days) of IBA1+ cells in the core of the infarct, which subsequently subsides reaching a significantly lower level by 30-days (
In order to understand the feasibility of using HA-MAP hydrogel for brain repair, it was first investigated how long the gel lasts in the brain after implantation and if they are any detrimental effects of hydrogel injection over time (
The brain tissue was subjected to immunohistological staining of cryosections of brain harvested from mice at the longest time point ˜120-days post injection. In brief, cryofrozen sections of the harvested brain tissue were allowed to thaw at room temperature. Sections were washed with PBS for 5 minutes with 3 repetitive washes. Sections were incubated with a 10% donkey serum and PBS with 0.3% triton at room temperature for one hour. The liquid was wicked away and primary antibodies of GFAP (glial fibrillary acidic protein) for astrocytes and NF200 (Neurofilament 200) for axonal processes at 1:100 dilution in PBS with 0.3% triton and 10% donkey serum were added and incubated overnight at 4° C. The next day, the primary antibodies were washed with 3 repeated PBS washes of 5 minutes each. Secondary antibodies with donkey hosts along with DAPI at 1:1000 dilution in PBS with 0.3% triton and 10% donkey serum were added and incubated at room temperature for 2 hours. After two hours, the secondary antibodies were washed away with 3 repeated PBS washes of 5 minutes each. The sections were allowed to dry at room temperature and mounted using DPX mounting medium. Analyses were performed on microscope images of 3 coronal brain levels at +0.80 mm, −0.80 mm and −1.20 mm according to bregma, which consistently contained the cortical infarct area. Large scale 10× images of each section was taken and analyzed for ventricular hypertrophy. The ratio of the ipsilateral length from the top of the section to the top of the ventricle was divided by the ratio of the contralateral length from the top of the section to the top of the ventricle was taken to get a quantitative number for the ventricular hypertrophy. Large scale 20× images were taken by the side of ventricle to analyze for nigrostriatal bundle area. Using pixel threshold on 8-bit converted images using ImageJ (Image J v1.43) and expressed as the area fraction of positive signal per area (%). Values were then averaged across all areas and sections, and expressed as the average positive area per animal. The percent area positive for NF200 was analyzed 0-1 mm out from the ventricle. Immunohistological staining of cryosections of brain harvested from mice at 120-days post injection showed long-lasting mechanical support was accompanied by maintenance of brain shape over time, which was significantly different from sham-treated mouse brain (
Atrophy can be observed in stroke patients and is known to cause effects at regions far away from the stroke core. Thus, cryosections of brain harvested from mice at the longest time point˜120-days post injection—were assessed to determine if there were other visible effects of a long-lasting hydrogel in the brain post stroke and reduced cerebral atrophy in mice. The striatal white matter bundles, which include the nigrostriatal bundles, were visible with NF200 staining, and were more preserved in the brains treated with HA-MAP hydrogel compared to sham brains (
To determine if the composition of the MAP gel affects global brain size or cortex size, MAP hydrogels were prepared where one gel had a ˜350 Pa storage modulus and a second MAP hydrogel had a ˜800 Pa storage modulus. The hydrogels were injected individually into mice 5-days after stroke using the methods disclosed in Example 2. Brains of mice were then harvested days 2, 10, 30, 120 days post injection and the brain crossectional area was measured.
The use of HA-MAP hydrogels to modulate astrocyte phenotype was assessed. HA-MAP hydrogel was injected 5-days post stroke and tissue was collected 2-days post injection according to methods disclosed in the Examples herein to assess astrocyte and microglial reactivity (
To assess astrocyte reactivity by immunohistochemisty (IHC), cryofrozen sections of harvested brain tissue were allowed to thaw at room temperature. Sections were washed with PBS for 5 minutes with 3 repetitive washes. Sections were incubated with a 10% donkey serum and PBS with 0.3% triton at room temperature for one hour. The liquid was wicked away and primary antibodies of GFAP (glial fibrillary acidic protein) for astrocytes and pERK for highly reactive astrocytes at 1:100 dilution in PBS with 0.3% triton and 10% donkey serum were added and incubated overnight at 4° C. The next day the primary antibodies were washed with 3 repeated PBS washes of 5 minutes each. Secondary antibodies with donkey hosts along with DAPI at 1:1000 dilution in PBS with 0.3% triton and 10% donkey serum were added and incubated at room temperature for 2 hours. After two hours, the secondary antibodies were washed away with 3 repeated PBS washes of 5 minutes each. The sections were allowed to dry at room temperature and mounted using DPX mounting medium. Analyses were performed on microscope images of 3 coronal brain levels at +0.80 mm, −0.80 mm and −1.20 mm according to bregma, which consistently contained the cortical infarct area. Each image represents a maximum intensity projection of 10 to 12 Z-stacks, 1 μm apart, captured at a 20× magnification with a Nikon C2 confocal microscope using the NIS Element software. For the sham sections, using ImageJ and converting to 8-bit, a ratio of positive pERK area divided by positive GFAP area within the same area was taken to get percent of reactive astrocytes that are highly reactive in the peri-infarct area 0-300 μm from the infarct border. For the HA MAP sections, the peri-infarct were analyzed similarly to sham. The infarct was analyzed by taking 0-100 μm infiltration into the lesion. S100β was stained, imaged, and analyzed similarly to pERK.
Additionally, quantitative RNA fluorescence in situ hybridization (RNA-FISH) was used to dive deeper into the reactive astrocyte phenotype. In brief, brain tissue sections were stored at −80° C. and equilibrated to room temperature before use. The brain tissue-mounted slides were immersed in 4% paraformaldehyde fixation buffer for 10 minutes at room temperature. Tissue was then permeabilized with 70% (v/v) ethanol for 24 hours at 4° C. Ethanol was aspirated and wash buffer was added. After incubation for 5 minutes at room temperature, the coverglass was transferred face-down onto Parafilm with 100 μL of hybridization Buffer containing hybridization probes for C3 (a marker shown to be upregulated in neurotoxic reactive astrocytes) and SLC1A2 (a marker for all astrocytes). After incubation for 16 hours in the dark at 37° C. in a sealed humidified chamber, the coverglass was washed with Wash Buffer A in the dark at 37° C. for 30 minutes. Nuclei were counterstained with Hoechst 33342 for 30 minutes, the tissue was then washed and prepared for visualization. Analyses were performed on microscope images of 3 coronal brain levels at +0.80 mm, −0.80 mm and −1.20 mm according to bregma, which consistently contained the cortical infarct area. Large scale 40× images were taken using a Nikon C2 confocal along the stroke border. The images were then analyzed for C3 and SLC1A2 in a manner similar to that used for positive pERK and S100β staining as detailed above.
Using a ratio of C3/SLC1A2 to analyze what percentage of astrocytes are highly reactive, it was observed that 54.2% of all astrocytes were reactive in the sham condition, while only 25.2% of all astrocytes were reactive in the 3.5% MAP gel peri-infarct condition. (
Microglial polarization directly affects astrocyte reactivity, with microglia that exhibit the more reactive M1 phenotype influencing astrocytes to a more highly reactive state. HA-MAP hydrogel was injected 5-days post stroke and brain tissue was harvested 2-days later in a manner similar to that described in the Examples above. Cryofrozen sections of the harvested brain tissue were allowed to thaw at room temperature before sections were washed with PBS for 5 minutes with 3 repetitive washes. Sections were incubated with a 10% donkey serum and PBS with 0.3% triton at room temperature for one hour. The liquid was wicked away and primary antibodies of CD11b for immune cells, Arginase 1 for Pro-repair microglia/macrophages, NOS2 for pro-inflammatory microglia/macrophages at 1:100 dilution in PBS with 0.3% triton and 10% donkey serum were added and incubated overnight at 4° C. The next day the primary antibodies were washed with 3 repeated PBS washes of 5 minutes each. Secondary antibodies with donkey hosts along with Dapi at 1:1000 dilution in PBS with 0.3% triton and 10% donkey serum were added and incubated at room temperature for 2 hours. After two hours, the secondary antibodies were washed away with 3 repeated PBS washes of 5 minutes each. The sections were allowed to dry at room temperature and mounted using DPX mounting medium. Analyses were performed on microscope images of 3 coronal brain levels at +0.80 mm, −0.80 mm and −1.20 mm according to bregma, which consistently contained the cortical infarct area. Each image represents a maximum intensity projection of 10 to 12 Z-stacks, 1 μm apart, captured at a 20× magnification with a Nikon C2 confocal microscope using the NIS Element software. In the peri-infarct for both sham and HA MAP, the ratio of the positive area of iNOS or Arg1 was divided by the positive area for CD11b from 0-300 μm from the infarct border. In the infarct, the ratio of the positive area of iNOS or Arg1 was divided by the positive area for CD11b from 0-300 μm from the infarct border.
Pro-repair microglia/macrophages were defined as expressing Arg1while pro-inflammatory microglia/macrophages expressing iNOS phenotype (
Chondroitin sulfate proteoglycans (CSPGs) have been linked to decreased regenerative potential in the CNS. HA-MAP hydrogel was injected 5-days post stroke and brain tissue was harvested 2-days later in a manner similar to that described in the Examples above. Immunohistochemistry was performed in a manner similar to that described in the Examples above where the primary, probing antibody was and anti-CSPG. Images were assessed in a similar manner as described above.
The amount of CSPGs in the HA-MAP treated mice significantly decreases in both the infarct (˜5.3%) and peri-infarct (˜9.8%) compared to sham infarct (˜59.7%) and peri-infarct (˜38%) (
One key difference between injection of HA-MAP into the stroke cavity compared to any other hydrogels that had been tested was that HA-MAP elicited astrocyte infiltration into the stroke cavity. Thus, rather than astrocytes forming a scar around the stroke core, as occurs in sham conditions, astrocytes changed their morphology and begin to infiltrate. Data presented herein with the PT stroke model showed that this finding was not model or cortex location specific.
To investigate if this change in morphology affected the scar thickness and if astrocyte infiltration was continuous over time, HA-MAP was injected in mice 5-days after stroke using methods similar to those described in the Examples herein. Brain tissue was harvested from the mice either 7, 15, or 30-days post stroke (
Astrocyte (GFAP+) cell infiltration was examined over time using an IHC method similar to that described in the Examples above. It was observed that astrocyte infiltration began within 2-days of hydrogel injection and continued to increase from 7-30-days post stroke, reaching close to 500 μm into the lesion by day 30 (
Next, microglia/macrophage reactivity over time was determined using a IHC method similar to those used in the Examples above, staining for IBA-1 (
Given the significant impact that HA-MAP had on the phenotype of astrocytes and the number of microglia, it was next assessed if changes in the stroke environment were accompanied with increases in axonogenesis. HA-MAP hydrogel was injected into the stroke cavity 5-days after stroke and axonal area (NF200+) in the peri-infarct as well as infiltration distance in the infarct quantified using IHC methods described in the Examples above (
The peri-infarct percent NF200+ area decreased from 53.2% to 20.4% comparing un-injured brain and stroke brain at 5-days, indicating the rapid loss of neurofilaments in the peri-infarct space after stroke (
In the infarct cavity, axonal infiltration for the HA-MAP hydrogel treated groups was observed, but not in the sham groups. The path of infiltration was similar to what the astrocytes follow, navigating between the HMPs rather than through the HMPs (
MAP hydrogels were injected individually into mice 5-days after stroke using the methods disclosed in the Examples above. Brains of mice were then harvested days 7, 15, and 30 days post injection and cryosections prepared. Using IHC methods similar to those described in the Examples herein, an initial increase in vessel density (Glut-1+) in the peri-infarct space was observed to be statistically significant at the 15-day time-point compared to sham mice (
After observing significant astrocyte/axonal infiltration into the stroke core, it was assessed if vessels also infiltrate the stroke core and if they follow a similar infiltration pattern (
Biomaterial and substrate stiffness has been shown to regulate astrocyte reactivity with softer substrates promoting astrocyte quiescence, suggesting that softer substrates should be used to better modulate astrocytes following stroke. Stiffness has also been implicated in axonal sprouting, vessel sprouting and microglia polarization.
A moderately stiffer HA-MAP hydrogel (3.5%=1000 Pa, 4.5%=1500 Pa) was generated to determine if gel stiffness change can affect astrocyte behavior. All other parameters, RGD concentration, HMP diameter, and void fraction were kept constant. MAP hydrogels were injected individually into mice 5-days after stroke using the methods disclosed in the Examples above. Brains of mice were then harvested days 7, 15, and 30 days post injection and cryosections prepared. Using IHC methods similar to those described in the Examples herein, scar thickness (GFAP), astrocyte infiltration (GFAP) into the infarct, reactive microglia (IBA-1) percent area in the peri-infarct and infarct, axon (NF200) infiltration into the infarct, and vessel (Glut1) infiltration into the infarct were assessed.
Overall, the 4.5% MAP hydrogel produced very similar results compared to the 3.5% hydrogel for astrocyte infiltration and scar thickness (
HA-MAP were produced from ˜80 μm HMPs, which contained HA (70,000 Da, 3.5%), RGD (500 μM), K and Q peptides (250 μM), and 7.8 mM of MMP crosslinker. The MAP gel was crosslinked using FXIIIa (5 U/mL) and 1 U/mL of thrombin. MAP hydrogels were injected individually into mice 5-days after stroke using the methods disclosed in the Examples above. Brains of mice were then harvested days 7 days post injection and cryosections prepared. Using IHC methods similar to those described in the Examples herein, scar thickness (GFAP), astrocyte infiltration (GFAP) into the infarct, and reactive microglia (IBA-1) percent area in the peri-infarct and infarct were assessed.
To test the role of microstructure on the observed findings, the observed results from HA-MAP were compared to those of a hydrogel with identical composition but crosslinked as a bulk gel (non-porous) (
Next, the effect of the integrin binding ligand RGD was tested (
Last, the role of the hydrogel backbone was tested and compared HA to polyethylene glycol (PEG) (
Taken together, this data showed that HA-MAP composition and microstructure was essential for the observed astrocyte infiltration, reduced scar thickness, and reduced microphage/microglia in the peri-infarct and infarct spaces. No other condition tested was equally effective as HA-MAP. Importantly, all the conditions that used HA as the backbone significantly decreased the scar thickness compared to conditions that used PEG as the backbone, demonstrating that the biological activity of HA played an important role in this process. After stroke, CD44 expression was elevated in reactive astrocytes. Thus, receptor mediated astrocyte/HA binding can be responsible for the infiltration in HA-MAP but not PEG-MAP. Implanting porous HA-RGD hydrogels into a cortex showed that RGD increased astrocyte infiltration into the cortex wound. These results agree with the finding that HA-MAP but not HA-MAP(-RGD) promoted astrocyte infiltration. It was surprising that PEG-MAP and HA-MAP resulted in different tissue responses. These materials had the same microstructures and same concentration of RGD. Given the large number of studies conducted using PEG hydrogels for tissue repair applications, it is possible that the results observed here were particular to brain and not generalizable to all tissues.
One skilled in the art will readily appreciate that the present disclosure is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The present disclosure described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the present disclosure. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the present disclosure as defined by the scope of the claims.
No admission is made that any reference, including any non-patent or patent document cited in this specification, constitutes prior art. In particular, it will be understood that, unless otherwise stated, reference to any document herein does not constitute an admission that any of these documents forms part of the common general knowledge in the art in the United States or in any other country. Any discussion of the references states what their authors assert, and the applicant reserves the right to challenge the accuracy and pertinence of any of the documents cited herein. All references cited herein are fully incorporated by reference, unless explicitly indicated otherwise.
The present disclosure shall control in the event there are any disparities between any definitions and/or description found in the cited references.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/933,599, filed Nov. 11, 2019, the contents of which is hereby incorporated by reference in its entirety.
This invention was made with Government support under Federal Grant No. R01NS094599 awarded by the National Institutes of Health. The Federal Government has certain rights to this invention.
| Number | Date | Country | |
|---|---|---|---|
| 62933599 | Nov 2019 | US |
