Patent Application
20230310697
This disclosure relates to methods and materials for embolization of one or more blood vessels (e.g., one or more arteries). For example, this disclosure provides hydrogel compositions for embolization of one or more blood vessels (e.g., one or more arteries) within a mammal (e.g., a human).
Hemorrhage in a setting of anticoagulation (ACA) is a serious medical emergency associated with high morbidity and mortality. In the US alone, there are over 2.6 million people with atrial fibrillation on ACA (Lloyd-Jones et al., Circulation, 121:948 (2010)). More than 30 million prescriptions for coumadin are written annually, and prescriptions for newer oral anticoagulants are also increasing; the bleeding frequency for coumadin alone is estimated to be 15-20 percent per year (Wysowski et al., Arch. Intern. Med., 167:1414 (2007); and Zareh et al., West. J. Emerg. Med., 12:386 (2011)). Bleeding risk is even higher in patients with mechanical valves and cardiac assist devices (CAD) (Eckman et al., Circulation, 125:3038 (2012); Kirley et al., Circ. Cardiovasc. Qual. Outcomes, 5:615 (2012); and Smith et al., J. Thorac. Dis., 7:2112 (2015)).
Introduced 15 years ago, liquid embolics are specially formulated materials designed to self-solidify upon deployment in situ. Once injected, liquid embolics undergo a transition to form a solid based on physicochemical mechanisms, including polymerization, precipitation and cross-linking through ionic, covalent, or thermal processes. Howeer, liquid embolics are associated with risks such as catheter entrapment (Qureshi et al., J. Vasc. Interv. Neurol., 8:37 (2015)), recanalization rates of up to 36% (Cekirge et al., Neuroradiology, 48:113 (2006)), and leakage during injection that can cause non-target embolization, angiotoxicity, and/or necrosis.
This disclosure provides methods and materials for embolization of one or more blood vessels (e.g., one or more arteries). For example, this disclosure provides hydrogel compositions for embolization (e.g., reversible embolization) of one or more blood vessels (e.g., one or more arteries) within a mammal (e.g., a human).
As demonstrated herein, a radiopaque hydrogel composition (e.g., a gel embolic material (GEM)) including 18% (w/v) Type A gelatin, 9% (w/v) silicate nanoplatelets, and either 10% (w/w) iohexol or 20% (w/w) tantalum particles) can be rapidly delivered into diseased blood vessels (e.g., vein or arteries) using clinical catheters to achieve embolization of first-order arteries such as the renal artery and iliac artery. Also as demonstrated herein, embolization using a radiopaque GEM including 18% (w/v) Type A gelatin, 9% (w/v) silicate nanoplatelets, and either 10% (w/w) iohexol or 20% (w/w) tantalum particles can be visualized in vivo using multiple imaging platforms.
Having the ability to perform embolization within a blood vessel of a mammal (e.g., a human) by delivering a hydrogel composition including gelatin, nanosilicates, and one or more radiopaque contrast agents provides a unique and unrealized opportunity to safely and quickly achieve hemostasis of one or more blood vessels within a mammal that can be visualized and monitored (e.g., during and/or following delivery). For example, a hydrogel composition including gelatin, nanosilicates, and one or more radiopaque contrast agents can be used to treat bleeding such as hemorrhage (e.g., hemorrhage of an internal organ). For example, using clinical catheters to deliver a hydrogel composition provided herein for embolization that is efficient, effective, safe, and/or cost-effective.
In general, one aspect of this disclosure features a hydrogel composition comprising: (a) gelatin; (b) a nanosilicate; and (c) a radiopaque contrast agent. The hydrogel composition can include from about 0.1% (w/v) to about 20% (w/v) of the gelatin. The hydrogel composition can include 18% (w/v) of the gelatin. The gelatin can be a Type A gelatin. The hydrogel composition can include from about 3% (w/v) to about 9% (w/v) of the nanosilicate. The hydrogel composition can include about 9% (w/v) of the nanosilicate. The nanosilicate can be a silicate nanoplatelet. The hydrogel composition can include from about 2% (w/w) to about 30% (w/w) of the radiopaque contrast agent. The hydrogel composition can include about 10% (w/w) of the radiopaque contrast agent, and the radiopaque contrast agent can include iohexol. The hydrogel composition can include about 20% (w/w) of the radiopaque contrast agent, and the radiopaque contrast agent can include tantalum particles. The viscosity of the hydrogel composition can decrease under a shear rate of about 10−1 1/s. The hydrogel composition can have a displacement pressure of from about 15 kPa to about 45 kPa.
In another aspect, this disclosure features methods for embolization of a blood vessel within a mammal. The methods can include, or consist essentially of, delivering a hydrogel composition including gelatin, a nanosilicate, and a radiopaque contrast agent to a blood vessel within a mammal. The mammal can be a human. The delivery can include catheter-directed delivery. The delivery can include a delivery rate of from about 1 mL/minute to about 2 mL/minute. The delivery can include from about 2 mL to about 5 mL of said hydrogel composition.
In another aspect, this disclosure features methods for reducing blood flow in a blood vessel within a mammal. The methods can include, or consist essentially of, delivering a hydrogel composition including gelatin, a nanosilicate, and a radiopaque contrast agent to a blood vessel within a mammal. The mammal can be a human. The delivery can include catheter-directed delivery. The delivery can include a delivery rate of from about 1 mL/minute to about 2 mL/minute. The delivery can include from about 2 mL to about 5 mL of said hydrogel composition.
In another aspect, this disclosure features methods for inducing clotting in a blood vessel within a mammal. The methods can include, or consist essentially of, delivering a hydrogel composition including gelatin, a nanosilicate, and a radiopaque contrast agent to a blood vessel within a mammal. The clotting can be induced in less than about 20 minutes following the delivery. The clotting can include the formation of a blot clot having a volume of from about 0.5 cubic centimeters (cm3) to about 5 cm3. The mammal can be a human. The delivery can include catheter-directed delivery. The delivery can include a delivery rate of from about 1 mL/minute to about 2 mL/minute. The delivery can include from about 2 mL to about 5 mL of said hydrogel composition.
In another aspect, this disclosure features methods for treating a mammal having a bleeding disorder. The methods can include, or consist essentially of, delivering a hydrogel composition including gelatin, a nanosilicate, and a radiopaque contrast agent to a blood vessel within a mammal. The bleeding disorder can be non-traumatic hemorrhage, traumatic hemorrhage, a saccular aneurysm, a vascular malformation, an endoleak, a gastroesophageal varices, or an arteriovenous fistula. The mammal can be a human. The delivery can include catheter-directed delivery. The delivery can include a delivery rate of from about 1 mL/minute to about 2 mL/minute. The delivery can include from about 2 mL to about 5 mL of said hydrogel composition.
In another aspect, this disclosure features methods for treating a mammal having a tumor. The methods can include, or consist essentially of, delivering a hydrogel composition including gelatin, a nanosilicate, and a radiopaque contrast agent to a blood vessel within a mammal that is feeding a tumor within the mammal. The tumor can be a benign tumor. The tumor can be a malignant tumor. The tumor can be a hepatic tumor, a uterine fibroid, a prostate tumor, a renal tumor, or a cerebral tumor. The mammal can be a human. The delivery can include catheter-directed delivery. The delivery can include a delivery rate of from about 1 mL/minute to about 2 mL/minute. The delivery can include from about 2 mL to about 5 mL of said hydrogel composition.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
In the description of embodiments, reference may be made to the accompanying figures which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized, and structural changes may be made without departing from the scope of the present invention. Unless otherwise defined, all terms of art, notations and other scientific terms or terminology used herein are intended to have the meanings commonly understood by those of skill in the art to which this invention pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art. Many of the aspects of the techniques and procedures described or referenced herein are well understood and commonly employed by those skilled in the art. The following text discusses various embodiments of the invention.
This disclosure provides methods and materials for embolization of one or more blood vessels (e.g., one or more arteries) within a mammal (e.g., a human). For example, this disclosure provides hydrogel compositions that can be delivered to one or more blood vessels (e.g., one or more arteries) within a mammal (e.g., a human) for embolization of the blood vessel(s). In some cases, one or more hydrogel compositions provided herein can be delivered to one or more blood vessels within a mammal (e.g., a human) to induce formation of a thrombus (e.g., an artificial embolus) within the blood vessel(s). In some cases, one or more hydrogel compositions provided herein can be delivered to one or more blood vessels within a mammal (e.g., a human) to form an embolus (e.g., an artificial embolus) within the blood vessel(s).
A hydrogel composition provided herein can include gelatin, one or more nanosilicates, and one or more radiopaque contrast agents. In some cases, a hydrogel composition provided herein can be sterile. In some cases, a hydrogel composition provided herein can be anti-bacterial. In some cases, a hydrogel composition provided herein can be bioactive. For example, a hydrogel composition provided herein can include one or more therapeutic agents.
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include any type of gelatin. In some cases, a hydrogel composition can include a single type of gelatin. In some cases, a hydrogel composition can include two or more (e.g., two, three, four, or more) types of gelatin. In some cases, a gelatin can be a synthetic gelatin. In some cases, a gelatin can be extracted from a tissue (e.g., skin, bone, and connective tissues) of an animal. Examples of types of gelatin that can be included in a hydrogel composition provided herein include, without limitation, Type A gelatin, Type B gelatin, gelatin extracted from cattle, gelatin extracted from pigs, and gelatin extracted from fish.
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include any amount of gelatin. For example, a hydrogel composition provided herein can include from about 0.1% (w/v) to about 20% (w/v) gelatin (e.g., from about 0.5% (w/v) to about 20% (w/v) gelatin, from about 1% (w/v) to about 20% (w/v) gelatin, from about 5% (w/v) to about 20% (w/v) gelatin, from about 10% (w/v) to about 20% (w/v) gelatin, from about 12% (w/v) to about 20% (w/v) gelatin, from about 15% (w/v) to about 20% (w/v) gelatin, from about 17% (w/v) to about 20% (w/v) gelatin, from about 0.1% (w/v) to about 18% (w/v) gelatin, from about 0.1% (w/v) to about 15% (w/v) gelatin, from about 0.1% (w/v) to about 12% (w/v) gelatin, from about 0.1% (w/v) to about 10% (w/v) gelatin, from about 0.1% (w/v) to about 8% (w/v) gelatin, from about 0.1% (w/v) to about 5% (w/v) gelatin, from about 0.5% (w/v) to about 18% (w/v) gelatin, from about 1% (w/v) to about 15% (w/v) gelatin, from about 5% (w/v) to about 12% (w/v) gelatin, from about 8% (w/v) to about 10% (w/v) gelatin, from about 1% (w/v) to about 5% (w/v) gelatin, from about 5% (w/v) to about 10% (w/v) gelatin, or from about 10% (w/v) to about 15% (w/v) gelatin). In some cases, a hydrogel composition provided herein can include about 18% (w/v) gelatin (e.g., Type A gelatin). In some embodiments, the hydrogels of the present disclosure comprise from about 0.2% to about 1.2% of gelatin (w/w), including about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1.0%, about 1.1%, and about 1.2%, including all values and ranges therebetween. In some embodiments, the hydrogels of the present disclosure comprise from about 0.6% to about 1.0% of gelatin (w/w), In some embodiments, the hydrogels of the present disclosure comprise from about 0.4% to about 0.8% of gelatin (w/w), In some embodiments, the hydrogels of the present disclosure comprise about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1.0%, about 1.1%, or about 1.2% of gelatin (w/w). In some embodiments, the hydrogels of the present disclosure comprise about 0.6% of gelatin (w/w). In some embodiments, the hydrogels of the present disclosure comprise about 0.8% of gelatin (w/w).
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include any type of nanosilicate(s). In some cases, a hydrogel composition can include a single type of nanosilicate. In some cases, a hydrogel composition can include two or more (e.g., two, three, four, or more) types of nanosilicates. Examples of nanosilicates that can be included in a hydrogel composition provided herein include, without limitation, lithium magnesium sodium silicates such as Laponite° -based silicate nanoplatelets (e.g., Laponite® XLG-based silicate nanoplatelets, Laponite® XLS-based silicate nanoplatelets, Laponite® XL21-based silicate nanoplatelets, and Laponite° D-based silicate nanoplatelets).
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include any amount of nanosilicates. For example, a hydrogel composition provided herein can include from about 3% (w/v) to about 9% (w/v) nanosilicates (e.g., from about 4% (w/v) to about 9% (w/v) nanosilicates, from about 5% (w/v) to about 9% (w/v) nanosilicates, from about 6% (w/v) to about 9% (w/v) nanosilicates, from about 7% (w/v) to about 9% (w/v) nanosilicates, from about 8% (w/v) to about 9% (w/v) nanosilicates, from about 3% (w/v) to about 8% (w/v) nanosilicates, from about 3% (w/v) to about 7% (w/v) nanosilicates, from about 3% (w/v) to about 6% (w/v) nanosilicates, from about 3% (w/v) to about 5% (w/v) nanosilicates, from about 3% (w/v) to about 4% (w/v) nanosilicates, from about 4% (w/v) to about 8% (w/v) nanosilicates, from about 5% (w/v) to about 7% (w/v) nanosilicates, from about 3% (w/v) to about 5% (w/v) nanosilicates, from about 4% (w/v) to about 6% (w/v) nanosilicates, from about 5% (w/v) to about 7% (w/v) nanosilicates, or from about 6% (w/v) to about 8% (w/v) nanosilicates). In some cases, a hydrogel composition provided herein can include about 9% (w/v) nanosilicates (e.g., silicate nanoplatelets). In some embodiments, the hydrogels of the present disclosure comprise from about 2.5% to about 6% of nanosilicates (w/w), including about 2.5%, about 3.0%, about 3.5%, about 4.0%, about 4.5%, about 5.0%, about 5.5%, and about 6.0%, including all values and ranges therebetween. In some embodiments, the hydrogels comprise from about 3.0% to about 4.0% of nanosilicates (w/w). In some embodiments, the hydrogels comprise from about 3.25% to about 3.75% of nanosilicates (w/w). In some embodiments, the hydrogels comprise from about 4.0% to about 5.5% of nanosilicates (w/w). In some embodiments, the hydrogels comprise from about 4.25% to about 5.25% of nanosilicates (w/w). In some embodiments, the hydrogels comprise from about 4.5% to about 5.0% of nanosilicates (w/w). In some embodiments, the hydrogels comprise about 2.75%, about 3.0%, about 3.25%, about 3.5%, about 3.75%, 4.0%, about 4.25%, about 4.5%, about 4.75%, about 5.0%, about 5.25%, or about 5.5% of nanosilicates (w/w). In some embodiments, the hydrogels comprise about 4.75% of nanosilicates (w/w). In some embodiments, the hydrogels comprise about 4% of nanosilicates (w/w). In some embodiments, the hydrogels comprise about 3.5% of nanosilicates (w/w).A hydrogel composition provided herein can have any ratio of gelatin to nanosilicates. For example, a hydrogel composition provided herein can have a ratio of gelatin to nanosilicates of from about 1:2 to about 1:9 (e.g., from about 1:2 to about 1:8, from about 1:2 to about 1:7, from about 1:2 to about 1:6, from about 1:2 to about 1:5, from about 1:2 to about 1:4, from about 1:3 to about 1:9, from about 1:4 to about 1:9, from about 1:5 to about 1:9, from about 1:6 to about 1:9, from about 1:7 to about 1:9, from about 1:3 to about 1:8, from about 1:4 to about 1:7, from about 1:5 to about 1:6, from about 1:2 to about 1:4, from about 1:3 to about 1:6, from about 1:4 to about 1:7, or from about 1:5 to about 1:8). In some cases, a hydrogel composition provided herein can have a ratio of gelatin to nanosilicates of about 1:6.
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include water (e.g., ultrapure water). In some cases, a hydrogel composition provided herein can have a ratio of gelatin to nanosilicates to water of about 1:5:6. In some cases, a hydrogel composition provided herein can have a ratio of gelatin to nanosilicates to water of about 1:6:5.
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include any type of radiopaque contrast agent(s). In some cases, a hydrogel composition can include a single type of radiopaque contrast agent. In some cases, a hydrogel composition can include two or more (e.g., two, three, four, or more) types of radiopaque contrast agents. Examples of radiopaque contrast agents that can be included in a hydrogel composition provided herein include, without limitation, iodinated molecules (e.g., iohexol, iopromide, iodixanol, ioaglate, iothalamate, and iopamidol), tantalum particles (e.g., tantalum nanoparticles), gold nanoparticle (AuNPs), ethiodized oil (e.g., Lipiodol®, lanthanide-based contrast agents, and bismuth. When a hydrogel composition provided herein includes tantalum particles, the tantalum particles can be any appropriate size of tantalum particles. In some cases, tantalum particles included in a hydrogel composition provided herein can be essentially the same size. In some cases, tantalum particles included in a hydrogel composition provided herein can have different sizes. Examples of tantalum particles that can be included in a hydrogel composition provided herein include, without limitation, tantalum microparticles (e.g., tantalum particles having an average size of about 2 μm), and tantalum nanoparticles (e.g., tantalum particles having an average size of about <25 nm). In some cases, a hydrogel composition provided herein can include tantalum particles having an average size of about 2 μm. In some cases, a hydrogel composition provided herein can include tantalum particles having an average size of about 30 μm. In some cases, a hydrogel composition provided herein can include tantalum particles having an average size of about 2 nm. In some embodiments, the hydrogels of the present disclosure comprise tantalum particles having a median particle size of about 1 μm to about 15 μm, including about 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, and 14 μm and all values and ranges therebetween. In some embodiments, the hydrogels of the present disclosure comprise tantalum particles having a median particle size of about 2 um to about 5 μm.
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include any amount of radiopaque contrast agent(s). For example, a hydrogel composition provided herein can include from about 2% (w/w) to about 30% (w/w) radiopaque contrast agent(s) (e.g., from about 2% (w/w) to about 25% (w/w), from about 2% (w/w) to about 20% (w/w), from about 2% (w/w) to about 15% (w/w), from about 2% (w/w) to about 10% (w/w), from about 2% (w/w) to about 5% (w/w), from about 5% (w/w) to about 30% (w/w), from about 10% (w/w) to about 30% (w/w), from about 15% (w/w) to about 30% (w/w), from about 20% (w/w) to about 30% (w/w), from about 25% (w/w) to about 30% (w/w), from about 5% (w/w) to about 25% (w/w), from about 10% (w/w) to about 20% (w/w), from about 5% (w/w) to about 10% (w/w), from 10% (w/w) to about 15% (w/w), from about 15% (w/w) to about 20% (w/w), or from about 20% (w/w) to about 25% (w/w)). In some cases, a hydrogel composition provided herein can include about 10% (w/w) radiopaque contrast agent(s) (e.g., about 10% (w/w) iohexol). In some cases, a hydrogel composition provided herein can include about 10% (w/w) radiopaque contrast agent(s) (e.g., about 20% (w/w) tantalum particles such as tantalum microparticles).
In some embodiments, the hydrogels of the present disclosure comprise from about 10% (w/w) to about 30% (w/w) of tantalum particles, including about 15%, about 20%, and about 25%, and all values and ranges thereof. In some embodiments, the hydrogels of the present disclosure comprise from about 15% (w/w) to about 25% (w/w) of tantalum particles. In some embodiments, the hydrogels of the present disclosure comprise about 20% (w/w) of tantalum particles.
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be visualized (e.g., within a mammal) using any appropriate method. For example, imaging techniques such as ultrasound, computed tomography, magnetic resonance imaging, and/or fluoroscopy can be used to visualize a hydrogel composition provided herein.
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include 18% (w/v) gelatin, 9% (w/v) silicate nanoplatelets, and 10% (w/w) iohexol.
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can include 18% (w/v) gelatin, 9% (w/v) silicate nanoplatelets, and 20% (w/w) tantalum microparticles. In some embodiments, the present disclosure provides a hydrogel comprising gelatin, silicate nanoplatelets and tantalum microparticles. In some embodiments, the present disclosure provides a hydrogel consisting essentially of gelatin, silicate nanoplatelets, tantalum microparticles and water (e.g., deionized water).
In some embodiments, the hydrogels of the present disclosure comprise:
In some embodiments, the hydrogels of the present disclosure comprise:
In some embodiments, the hydrogels of the present disclosure comprise:
In some embodiments, the hydrogels of the present disclosure comprise:
In some embodiments, the hydrogels of the present disclosure comprise:
In some embodiments, the hydrogels of the present disclosure comprise:
In some embodiments, the hydrogels of the present disclosure comprise:
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be biodegradable. For example, a volume of a hydrogel composition delivered to a blood vessel within a mammal (e.g., a human) can decrease over time. In some cases, a volume of a hydrogel composition delivered to a blood vessel within a mammal (e.g., a human) can decrease by at least about 25% (e.g., at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 75%) over time. In some cases, a volume of a hydrogel composition delivered to a blood vessel within a mammal (e.g., a human) can decrease for about 28 days following delivery. In some cases, a volume of a hydrogel composition delivered to a blood vessel within a mammal (e.g., a human) can decrease by about 75% for about 28 days following delivery.
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be a shear-thinning hydrogel composition. For example, a viscosity of a hydrogel composition provided herein can decrease under a shear rate of about 10−1 1/s.
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can have a displacement pressure that is higher than the mean pressure of a blood vessel (e.g., healthy blood vessel or a blood vessel that has been embolized with coils). For example, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can have a displacement pressure of from about 15 kPa to about 45 kPa.
A hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be made using any appropriate method. In some cases, gelatin and one or more nanosilicates can mixed first, and then one or more radiopaque contrast agents can be added. For example, centrifugal mixing, manual mixing, high shear dispersing, vacuum mixing, vortexing, and/or syringe mixing can be used for mixing (e.g., homogenous mixing) of gelatin, one or more nanosilicates, and one or more radiopaque contrast agents to make a hydrogel composition provided herein. In some cases, a hydrogel composition can be made as described in Example 1.
Optionally, the hydrogel compositions of the invention can include one or more bioactive agents such as an embolic agent, an anti-inflammatory agent, an agent that modulates coagulation, an antibiotic agent, a chemotherapeutic agent or the like. Hydrogel compositions of the invention can be formulated for use as carriers or scaffolds of bioactive agents such as drugs, cells, proteins, and bioactive molecules (e.g., antibodies and enzymes). As carriers, such compositions can incorporate the agents and deliver them to a desired site in the body for the treatments of a variety of pathological conditions. Illustrative embolic agents include, for example, stainless steel coils, absorbable gelatin pledgets and powders, polyvinyl alcohol foams, ethanol, glues and the like. Illustrative hemostatic agents include, for example, Celox, QuikClot and Hemcon. Certain illustrative materials and methods that can be adapted for use in such embodiments of the invention are found, for example in Hydrogels: Design, Synthesis and Application in Drug Delivery and Regenerative Medicine 1st Edition, Singh, Laverty and Donnelly Eds; and Hydrogels in Biology and Medicine (Polymer Science and Technology) UK ed. Edition by J. Michalek et al. In addition, as scaffolds, compositions of the invention can provide a flexible dwelling space for cells and other agents for use in tissue repair and the regeneration of desired tissues (e.g. for cartilage, bone, retina, brain, and, neural tissue repair, vascular regeneration, wound healing and the like).
In some cases, a hydrogel composition provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be sterilized. Any appropriate method can be used to sterilize a hydrogel composition provided herein. For example, irradiation (e.g., ionizing irradiation), gamma irradiation, electron beam irradiation, gas (e.g., ethylene oxide) based irradiation, and/or x-ray irradiation can be used to sterilize a hydrogel composition provided herein. In some cases, a hydrogel composition can be sterilized as described in Example 1.
Also provided herein are methods for using one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents). In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be used for embolization of one or more blood vessels within a mammal (e.g., a human). For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal for embolization of the blood vessel(s). In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be used for embolization without fragmentation of the delivered hydrogel compositions. In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be used for embolization without migration of the hydrogel compositions. In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be used for embolization having a recanalization rate of less than about 35% (e.g., less than about 30%, less than about 25%, less than about 20%, less than about 15%, or less than about 10%).
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) to reduce or eliminate blood flow within the blood vessel(s). For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) to reduce blood flow within the blood vessel(s) by for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or more percent.
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) to induce clotting within the blood vessel(s). For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) to induce clotting within the blood vessel(s) in less than about 20 minutes (e.g., less than about 15 minutes, less than about 12 minutes, less than about 10 minutes, less than about 8 minutes, or less than about 3 minutes). For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) to induce formation of a blood clot within the blood vessel(s) that has a mass or size (e.g., a volume) of from about 0.5 cubic centimeters (cm3) to about 5 cm3 (e.g., from about 0.5 cm3 to about 4.5 cm3, from about 0.5 cm3 to about 4 cm3, from about 0.5 cm3 to about 3.5 cm3, from about 0.5 cm3 to about 3 cm3, from about 0.5 cm3 to about 2.5 cm3, from about 0.5 cm3 to about 2 cm3, from about 0.5 cm3 to about 1.5 cm3, from about 0.5 cm3 to about 1 cm3, from about 1 cm3 to about 5 cm3, from about 1.5 cm3 to about 5 cm3, from about 2 cm3 to about 5 cm3, from about 2.5 cm3 to about 5 cm3, from about 3 cm3 to about 5 cm3, from about 3.5 cm3 to about 5 cm3, from about 4 cm3 to about 5 cm3, from about 4.5 cm3 to about 5 cm3, from about 1 cm3 to about 4.5 cm3, from about 1.5 cm3 to about 4 cm3, from about 2 cm3 to about 3.5 cm3, from about 2.5 cm3 to about 3 cm3, from about 0.5 cm3 to about 1.5 cm3, from about 1.5 cm3 to about 2.5 cm3, from about 2.5 cm3 to about 3.5 cm3, or from about 3.5 cm3 to about 4.5 cm3).
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) having a bleeding disorder to treat the mammal. For example, a hydrogel composition provided herein can be delivered to one or more blood vessels feeding one or more tumors within the mammal to reduce or eliminate blood flow associated with the bleeding disorder. Examples of bleeding disorders that can be treated as described herein (e.g., by delivering a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents to one or more blood vessels within a mammal) include, without limitation, hemorrhage (e.g., non-traumatic hemorrhage and traumatic hemorrhage), saccular aneurysms, vascular malformations, endoleaks, gastroesophageal varices (e.g., bleeding gastroesophageal varices), and arteriovenous fistulas.
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) having one or more tumors to treat the mammal. For example, a hydrogel composition provided herein can be delivered to one or more blood vessels feeding one or more tumors within the mammal to reduce or eliminate blood flow to the tumor(s). In some cases, a tumor can be a malignant tumor. In some cases, a tumor can be a benign tumor. Examples of tumors that can be treated as described herein (e.g., by delivering a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents to one or more blood vessels within a mammal) include, without limitation, hepatic tumors, uterine fibroids, prostate tumors, renal tumors, and cerebral tumors. For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels feeding one or more tumors within a mammal (e.g., a human) to reduce the size (e.g., volume) of the tumor(s) by for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or more percent.
In some cases, when one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are delivered to one or more blood vessels within a mammal (e.g., a human), the mammal can experience minimal or no complications associated with embolization. Examples of complications associated with embolization include, without limitation, vasospasm, thrombosis, dissections, rupture, necrosis, bleeding at the puncture site, and hematoma at the puncture site.
One or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within any type of mammal. In some cases, a mammal (e.g., a human) can be anticoagulated (e.g., can be taking one or more anticoagulants). In some cases, a mammal (e.g., a human) can be coagulopathic (e.g., can have a bleeding disorder in which the mammal's blood's ability to coagulate is impaired). Examples of mammals that can have one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) delivered to one or more blood vessels within the mammal include, without limitation, humans, non-human primates such as monkeys, dogs, cats, horses, cows, pigs, sheep, mice, rats, and rabbits.
One or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to any type of blood vessel within a mammal (e.g., a human). In some cases, a blood vessel can be a diseased blood vessel. In some cases, a blood vessel can be an injured blood vessel. Examples of types of blood vessels into which a hydrogel composition provided herein can be delivered include, without limitation, arteries, veins, and capillaries. When one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are delivered to an artery, the artery can be any artery within a mammal (e.g., a human) such as a renal artery, an iliac artery, a gastric artery, a prostate artery, or a mesenteric artery. When one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are delivered to a vein, the vein can be any vein within a mammal (e.g., a human) such as a portal vein, and a pelvic vein.
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to the lymphatic system within a mammal (e.g., a human).
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to the site of an endoleak (e.g., an endoleak of a vascular graft following repair).
One or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to any size blood vessel within a mammal (e.g., a human). In some cases, a blood vessel can have a diameter (e.g., a luminal diameter) of from about 50 microns to about 10,000 microns (1 cm) (e.g., about 50 microns to about 5,000 microns, about 50 microns to about 1,500 microns, about 50 microns to about 1,000 microns, about 50 microns to about 900 microns, about 50 microns to about 800 microns, about 50 microns to about 700 microns, about 50 microns to about 600 microns, about 50 microns to about 500 microns, about 50 microns to about 400 microns, about 50 microns to about 300 microns, about 50 microns to about 200 microns, about 50 microns to about 100 microns, about 100 microns to about 10,000 microns, about 200 microns to about 10,000 microns, about 300 microns to about 10,000 microns, about 400 microns to about 10,000 microns, about 500 microns to about 10,000 microns, about 600 microns to about 10,000 microns, about 700 microns to about 10,000 microns, about 800 microns to about 10,000 microns, about 900 microns to about 10,000 microns, about 1,000 microns to about 10,000 microns, about 5,000 microns to about 10,000 microns, about 100 microns to about 5,000 microns, about 200 microns to about 1,000 microns, about 300 microns to about 900 microns, about 400 microns to about 800 microns, about 500 microns to about 700 microns, about 100 microns to about 400 microns, about 200 microns to about 500 microns, about 300 microns to about 600 microns, about 400 microns to about 700 microns, about 500 microns to about 800 microns, about 600 microns to about 900 microns, or about 700 microns to about 1,000 microns).
When delivering one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) to one or more blood vessels within a mammal (e.g., a human), any appropriate method of delivery can be used. In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) by injection directly to a blood vessel (e.g., a blood vessel in need of embolization). In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) by catheter-directed delivery (e.g., via a catheter inserted into a blood vessel in need of embolization). When one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are delivered to one or more blood vessels within a mammal (e.g., a human) by catheter-directed delivery any type of catheter can be used (e.g., a Bernstein catheter, a microcatheter, a Cobra catheter, a Fogarty balloon, and a ProGreat catheter). When one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are delivered to one or more blood vessels within a mammal (e.g., a human) by catheter-directed delivery any size catheter can be used. For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) using a catheter having a size of from about 2.8 French to about 5 French.
One or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) at any delivery rate. For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) at a rate of from about 1 mL/minute to about 2 mL/minute.
Any amount of one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human). For example, from about 2 mL to about 5 mL (e.g., from about 2 mL to about 4 mL, from about 2 mL to about 3 mL, from about 3 mL to about 5 mL, from about 4 mL to about 5 mL, from about 2 mL to about 3 mL, or from about 3 mL to about 4 mL) of one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human).
In some cases, after one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are used for embolization of one or more blood vessels within a mammal (e.g., a human), the hydrogel composition(s) can be retrieved from the blood vessel(s). For example, after one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are delivered to one or more blood vessels within a mammal for embolization of the blood vessel(s), the hydrogel composition can be retrieved to increase (e.g., restore) blood flow through the blood vessel(s). Any appropriate method can be used to retrieve one or more hydrogel compositions provided herein from one or move blood vessels within a mammal (e.g., a human). For example, aspiration catheters (e.g., aspiration through the delivery catheter), and surgical removal can be used to retrieve one or more hydrogel compositions provided herein from one or move blood vessels within a mammal (e.g., a human).
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) as the sole active agent used for embolization.
In some cases, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) in combination with one or more additional agents used for embolization. For example, one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) can be delivered to one or more blood vessels within a mammal (e.g., a human) in combination with solid embolic materials (e.g., a coils, particles, foam, a plug, microspheres, and/or beads), liquid embolic materials (e.g., butyl cyanoacrylate (n-BCA), and Onyx®).
In cases where one or more hydrogel compositions provided herein (e.g., a hydrogel composition including gelatin, one or more nanosilicates, and one or more radiopaque contrast agents) are used in combination with additional agents used for embolization, the one or more additional agents can be administered at the same time (e.g., in the same composition or in separate compositions) or independently. For example, one or more hydrogel compositions provided herein can be administered first, and the one or more additional agents administered second, or vice versa.
The invention will be further described in the following examples, which do not limit the scope of the invention described in the claims.
A major concern for gel-like embolic agents is the potential for fragmentation during delivery, which can lead to non-target distal embolization and unintended tissue ischemia. To evaluate the stability of GEM in a high velocity and high-pressure vasculature, a rat model of femoral artery occlusion was created. In this model, arterial flow at the femoral artery (FA) is occluded with GEM; however, flow to the distal hindlimb is preserved by the collateral flow. Any breakdown of GEM will travel distally in the hindlimb of the rat and manifest as loss of perfusion to that digit or limb. Following the delivery of GEM directly into FA (
To assess durability and biodegradation of GEM in FA, quantitative micro-CT imaging and histology were performed at days 0, 3, 7, and 21. Axial images of FA at 10-micron resolution demonstrated uniform casting of the FA lumen, including smaller tortuous side branches such as the lateral circumflex artery (
GEM embolization of the FA causes initial distension of the arterial lumen and thinning of the arterial wall; after 21 days, the arterial wall becomes thickened as the GEM biodegrades and remodels reducing arterial wall-tension and decreases arterial lumen area (
To evaluate the efficacy of GEM embolization in a setting of anticoagulation, the rat model of FA occlusion was repeated in heparinized rats with activated clotting time (ACT) values over 300 seconds (
To assess the systemic response to GEM embolization, a quantitative evaluation of 27 cytokines and chemokines was performed using the rat serum isolated at day 0, 3, 7, and 21 days. Results show that there was no significant increase in pro-inflammatory mediators such as TNF-α, IL-1β, IL-6, and MIP-1α in serum samples compared to baseline. In contrast, there was a significant increase in anti-inflammatory cytokines such as IL-1α, IL-10, and IL-4 peaking at day 7 and returning to baseline by 21 days. These suggest that intra-arterial GEM injection did not incite a systemic pro-inflammatory cytokine response, further supporting its biocompatibility and safety profile (Table 1).
Prior to testing GEM in a swine model of embolization, visualization of GEM during real-time X-ray fluoroscopy was optimized since this is critical to achieving targeted and controlled delivery. Clinically, metallic coils used today for embolization are visible during fluoroscopy; however, they produce significant artifacts with CT imaging, MRI, and US. The inability to assess the outcome of the intervention following embolization due to artifact is a major setback in clinical practice today. Here, it is shown that a formulation for GEM that would allow GEM and local anatomical visualization in all imaging modalities, including CT, MRI, US and fluoroscopy without significant artifact.
In rat experiments, GEM made with 10% iohexol was inadequate for visualization with fluoroscopy imaging, as shown in
The capability to hand inject a syringe-filled Ta-GEM connected to a clinical catheter was a key practical requirement for the design of GEM. To determine whether Ta-GEM is suitable for transcatheter delivery, the injectability of GEM and Ta-GEM through 2.8 French and 5 French clinical catheters, respectively, was examined using compression testing (
In addition to inj ectability, the influence of Ta micro-particles on GEM's mechanical property was analyzed using rheological studies. The flow curves of GEM and Ta-GEM demonstrate similar shear thinning characteristics (
Enhanced thrombogenicity of Ta-GEM is a favorable trait in an embolic agent to achieve vascular occlusion. Blood coagulation in aliquots of citrated human blood mixed with Ta-GEM was compared to standard coils used in patients. Both coils, GEM and Ta-GEM demonstrated clot promoting properties when compared to blood alone; however, when the mass of the clot is measured, Ta-GEM demonstrated a significant rise in mass beginning at 3 minutes compared to GEM and blood alone (
To sterilize Ta-GEM, a desktop X-ray irradiator (RS2000, RAD.SOURCE) was used. Following 11 cGy/minutes of ionizing radiation for a total dose of 12000 rads exposure to GEM, which is sufficient to eradicate bacteria and fungus, there was no detectable microbial growth in the irradiated samples confirming its sterility (
The embolization efficacy of GEM was tested in the swine arterial system. Experiments were designed to evaluate the performance of GEM compared to coils in the embolization of first-order arteries in a state of extreme anticoagulation. It was also investigated whether coils that failed to achieve hemostasis could be subsequently rescued by GEM injection into the coil mass and whether GEM could be retrieved from the artery following injection. Today, no embolization coil can achieve hemostasis in a state of anticoagulation or coils designed to be removed after delivery.
Using clinical tools and imaging equipment, a combination of wire and a catheter was used to deliver the catheter tip to the distal abdominal aorta. Digital subtraction angiography (DSA) demonstrated the characteristic split of the aorta into the paired external and internal iliac arteries. Following injection of 20-30,000 Units of IV Heparin to achieve ACT >300 seconds, the iliac artery was catheterized; approximately 6-7 cm of the iliac artery was subsequently embolized with GEM through a 5 French Bernstein catheter or a 2.8 French microcatheter (
Next, it was tested whether coils that consistently failed to achieve occlusion and hemostasis, e.g.,
Non-target embolization is always a concern in embolization procedures. As a safety mechanism, it was evaluated whether GEM could be retrieved in the event of an unintended or accidental non-target embolization. In 5 cases, the iliac artery was embolized using GEM; after up to 3 hours, GEM was retrieved in its entirety using the Penumbra Aspiration catheter system (
Long term outcomes of using GEM in the embolization of swine iliac arteries while receiving daily antiplatelet therapy for anticoagulation were investigated. Following up to 28 days of survival post-embolization, the animals underwent contrast-enhanced CT angiogram (CTA) and then were euthanized. All 16 animals demonstrated persistent embolization at each time point with no evidence for non-target embolization on CTA imaging (
To assess for systemic toxicity and inflammatory response to GEM, complete blood count (CBC), basic metabolic panel (BMP), liver function tests (LFT), and a cytokine array analysis were performed; samples before embolization were compared to blood samples obtained just prior to sacrifice. Blood tests before and after embolization including CBC, LFTs and BMP were unremarkable (P>0.05, Table 2); this is a significant result because it indicates that GEM does not consume platelets, activate acute phase reactants, increase white blood cell counts because of an infection, or injure solid organs. Cytokine array analysis of the blood before and after embolization demonstrated no signs of inflammation, with most factors reduced in post embolization samples (Table 3). These blood tests, cytokine analysis, histology, and cross-sectional imaging of the pigs further demonstrate that GEM is biocompatible and safe without evidence of an adverse systemic response.
Iliac artery embolization demonstrated that GEM is stable with permanent occlusion (e.g., arterial occlusion without any evidence of flow through on angiographic imaging indicating that the embolization was stable) over 28 days. However, recanalization of the embolized arterial segment could not be excluded with certainty since CT images distal to the embolized iliac artery revealed contrast enhancement; this could have resulted from extensive cross-pelvic collateral flow bypassing the embolized segment or from recanalization. To assess for possible recanalization of GEM over time, the main renal artery in 16 pigs was embolized. The kidney is comprised of end-organ arteries; successful embolization of the main renal artery would result in distal ischemia and atrophy of the kidney. However, any recanalization of the GEM would lead to the restoration of blood flow and reduced or absence of atrophy. Furthermore, because the renal artery is an end-artery, the smallest vessel that could be embolized with GEM was also determined and confirmed by histology.
Using a 5 French Cobra catheter, the main renal artery was catheterized, confirmed by DSA imaging (
The embolization performance of GEM was compared to gelfoam, which is clinically used today for hemorrhage control. Similar to the gelatin used in GEM, gelfoam is also comprised of porcine gelatin. Pre-cut gelfoam (EmboCube, Meritt Medical) was mixed with 50% v/v saline and 50% iohexol to create a slurry. These were subsequently used to embolize the renal artery to immediate occlusion (
Iohexol-free GEM was prepared by mixing 18% (w/v) gelatin (Type A, Sigma Aldrich, St. Louis, MO, USA), 9% (w/v) silicate nanoplatelets (Laponite XLG, BYK USA Inc., Rochester Hills, MI, USA) and ultrapure water at a weight ratio of 1:6:5, according to a as described elsewhere (see, e.g., Avery et al., Sci. Transl. Med., 8:365ra156 (2016); and Gaharwar et al., ACS Nano., 8:9833 (2014)). To introduce radiopacity, GEM was mixed with iohexol or tantalum particles. Iohexol solution (Omnipaque 350 mgI/mL, GE HealthCare, MA) was mixed into GEM to achieve a 10% w/w final concentration. Tantalum microparticles (Ta) with an average size of 2 μm (Alfa Aesar, Haverhill, MA, USA) or tantalum nanoparticles <25 nm particle size (Sigma-Aldrich, St. Louis, MO) were mixed with GEM at various w/w levels to form GEM-Ta hydrogel (e.g., 20% w/w Ta GEM). The homogenous mixing of all GEM formulations was achieved by using a SpeedMixer (FlackTek Inc., Landrum, SC). To sterilize GEM, a RS2000 irradiator system (RAD. SOURCE) was used to expose GEM loaded syringes to 160 kV, 25 mA of ionizing irradiation dose equivalent to 11 cGy/minute for a total of 12000 rads based on an established protocol to eradicate bacteria and fungus. To confirm sterility, standard microbial growth assay using LB agar plates or LB broth with and without 100 mg/mL ampicillin was performed. LB broth tubes containing 107-108 CFU of chemically competent E. coli bacteria were used as a positive control. LB broth tubes which had 0.1 mL PBS alone served as a negative control. Quadruplicate tubes from GEM batches and each control were prepared and incubated on a shaking platform inside a 37° C. incubator for up to 7 days. The analysis was performed as described in Avery et al., Sci. Transl. Med., 8:365ra156 (2016).
Flow curves and amplitude sweeps were performed as described elsewhere (see, e.g., Avery et al., Sci. Transl. Med., 8:365ra156 (2016)). The rheological evaluation of GEM was performed using an Anton Paar MCR 302 rheometer (Anton Paar USA Inc., Torrance, CA, USA). A sandblasted 25 mm diameter aluminum upper plate and an aluminum lower plate, with a 500 μm gap in between, were used for all measurements. Flow curves and amplitude sweeps (at 10 rad/s) were obtained at 25° C. and 37° C. For tests at 37° C., the solvent trap was used, and the edge of the solvent trap was filled with water to provide a humidified environment. Data were acquired at least in triplicates for each experiment.
Injectability was examined using a mechanical tester equipped with a 100 N load cell (Instron, Norwood, MA) according to the previously established protocols. Briefly, GEM was loaded into 1 mL or 3 mL luer-lock syringes (Medallion, Merit Medical, South Jordan, UT) and injected through a 110 cm 2.8 French ProGreat catheter (Terumo Medical Corporation, Somerset, NJ, USA) or a 100 centimeter 5F Bernstein catheter (Cook Medical Inc, Bloomington, IN), respectively. GEM containing syringes was inserted inside of a custom-designed 3D printed holder, and the plunger was placed against the load cell plate; the compression force was applied at either 2 mL/minute or 1 mL/minute rate for 5F and 2.8F respectively. To simulate injection during clinical practice, interrupted compression force was also applied for 10 seconds, followed by a 5 second pause; this cycle was repeated 8 times through a 5 French catheter. The generated break loose and injection forces overtime was acquired and plotted using Bluehill version-3 software (Instron, Norwood, MA, US). Injectability testing was repeated at least five times for each condition.
Clotting time and thrombus weight were quantified as described elsewhere (see, e.g., Avery et al., Sci. Transl. Med., 8:365ra156 (2016); and Gaharwar et al., ACS Nano., 8:9833 (2014)). Briefly, 0.5 grams of GEM aliquots were weighed into 2 mL microtubes. GEMs were centrifuged at 1000 RPM to standardize the blood interaction surface. Uncoagulated citrated blood was reactivated by adding 10% (v/v) 0.1 M CaCl2. 100 μL of activated blood was added to each GEM sample and allowed to react for 3, 8, 10, 12, 15, or 20 minutes. At each time point, clotting was stopped by the addition of 200 μL of 0.109 M sodium citrate solution. Residual liquid was removed, isolating the clotted blood. The clotted blood was weighed in each test tube to determine the mass.
All in vivo studies were approved by the institutional animal care and use committee (IACUC) and conducted in accordance with federal and institutional guidelines. The right femoral artery was dissected between the proximal profunda and the superficial caudal epigastric artery away from the femoral vein and nerve. Two 4-0 silk ligatures were looped around the distal and proximal ends to manipulate and stabilize the artery segment during the injection. A micro-vessel clamp was placed distal to the profunda branch. Following GEM injection using a 27-gauge needle, rats were randomly divided into four groups and survived for 0, 3, 7, or 21 days (n=6 in each group). Rats in the 0-day time-point were euthanized 1 hour following GEM embolization; these served as the control group. Each rat was serially imaged using laser speckle contrast imaging (LSCI) to quantify hind limb microperfusion, and motor function was assessed using the modified Tarlov scale. Imaging was performed by placing anesthetized rats in a prone position on a warming platform to maintain core temperature at 37° C. Following 5 minutes of stabilization, the laser was positioned over the rat at a set distance of 20 centimeters, and perfusion imaging was initiated. Data were acquired at baseline, immediately after injection, and at day 1 post-surgery, and subsequently once a week afterward. Perfusion data were calculated as a ratio of perfusion in the GEM injected hind limb paw to the contralateral non-injected hind limb paw and expressed as a percent of baseline.
Six rats received heparin before GEM injection into the femoral artery as described above and continued to receive anticoagulation therapy for 3 days post-GEM injection. Activated clotting time (ACT) was documented using iSTAT analyzer (Abbot, Princeton, NJ) in a 0.25 mL blood aliquot withdrawn from the caudal superficial epigastric vein before and after heparin administration. Once baseline ACT value was recorded, 1200 IU/kg heparin diluted in 250 μL normal saline was intravenously infused into the femoral vein branch. Subsequently, these rats received 150 IU/kg heparin subcutaneously twice a day for 3 days following GEM injection. A parallel group of 6 rats received a similar volume of saline instead of heparin serving as the control group.
This study was approved by the institutional animal care and use committee (IACUC). Yorkshire pigs (S&S Farms, Brentwoods, CA) weighing 48 to 55 kg were acclimatized for at least 4 days. Anesthesia was induced using intramuscular injection of 5 mg/kg tiletamine-zolazepam (Telazol, Zoetis), 2 mg/mL xylazine and 0.02 mg/kg g lycopyrrolate. Pigs were then placed in a supine position and intubated on an X-ray compatible operating table (Pannomed Aeron, DRE, KY). Following intubation, anesthesia was maintained with inhalation of 1.5-3% isoflurane. During the procedure, electrocardiogram, transcutaneous oxyhemoglobin saturation (SpO2), end-tidal CO2 concentration, inspired oxygen fraction, and core temperature was monitored. Percutaneous access to the carotid artery was obtained using ultrasound guidance (ACUSON 52000, Siemens) and fluoroscopy (OEC9800 plus C-Arm, GE Healthcare Systems, Chicago, IL). Access needle and wire were exchanged for a 5-French Bernstein catheter (Cook Medical). Over a GT-glidewire (Terumo Medical), the tip of the catheter was advanced to the renal or the iliac artery using contrast-enhanced fluoroscopy (350 mgI/mL Omnipaque, GE HealthCare, MA). Pigs received 10,000-30000 IU of heparin IV, and ACT levels were documented using iSTAT analyzer (Abbot Laboratories Princeton, NJ). GEM or EmboCube (Merit Medical) was delivered to the 1st order arterial branches iliac or renal artery using a catheter under real-time fluoroscopic guidance. Syringes with the embolic agent were connected directly to the catheter using the 1 uer-lock. In a subset, iliac arteries received metallic coils, including those from Medtronic, Terumo, Cook Medical, and Boston Scientific. The time to deployment of GEM or coils was recorded for each procedure. Following embolization, angiography was repeated multiple times to assess vessel patency. Pigs were either euthanized 1-hour post-embolization (non-survival group) or at 1, 2, or 4 weeks post-embolization (survival group). Prior to euthanasia, blood samples were obtained for analysis, and whole animal CTA imaging was performed. At necropsy, vascular tissues containing GEM or coils were explanted for μCT imaging and histopathology evaluation. Tissues from the liver, spleen, heart, and normal kidneys were also obtained for histology review to assess for potential toxicity.
CT acquisition was performed on a dual-source scanner (Siemens Force, Siemens Healthineers, Erlangen, Germany). The spiral scan was performed at 150 kVp and 80 kVp energy level, respectively with a 0.6 mm detector size configuration. The MRI acquisition was performed on a 3.0 T scanner (Siemens Skyra, Erlangen, Germany). The 20-channel head coil with the main body transmit coil was used to acquire the data. MRI acquisition consisted of axial single-shot T2, axial dual-echo in-phase and out-of-phase, T1-weighted imaging before, and balanced steady-state free precession. The Fluoroscopy acquisition was performed on a mobile C-arm (OEC 9800 Plus, GE Healthcare, Illinois, USA).
Explanted embolized vessels were fixed with 10% formalin and incubated in 70% ethanol for 24 hours. MicroCT imaging was performed using SkyScan 1276 (Bruker, Kontich, Belgium) at 33 kV, 223 μA for rat vessels and 45 kV and 200 μA for pig arteries at a pixel size of 10 μm. Data analysis was performed using NRecon, CTvox, Data Viewer and CTAn software (Bruker, Kontich, Belgium). To document structural changes in the injected GEM, a quantitative morphometric analysis was performed to calculate surface to volume ratio, surface convexity index, fractal dimension, and structure model index. To calculate GEM volume inside the embolized pig vessels, Mimics software (Materialise, Leuven, Belgium) was used to segment GEM and the vessel lumen.
Paraffin-embedded sections were stained with H&E, Mason's trichrome or EVG elastin stain, and immunostaining for myeloperoxidase (MPO; ab208670, Abcam) or CD68 (ab125212, Abcam) was performed as described elsewhere (see, e.g., Avery et al., Sci. Transl. Med., 8:365ra156 (2016)). Morphometric analysis was performed using image analysis software (Celleste 4.1, Thermo Fisher Scientific). A blinded observer counted MPO or CD68 positive cells.
Selected biomarkers, including cytokines, chemokines, and growth factors were measured in serum samples obtained from aliquots of blood samples from rats at 0, 3, 7 and 21 days and from pigs at 0, 1, 2, and 4 weeks post-embolization. The rat's serum samples were analyzed using the cytokine/chemokine array 27-plex, while the pig samples we analyzed using the porcine cytokine/chemokine array 13-plex (Eve Technologies, Calgary, CA). The analyte concentrations are expressed in picogram per mL.
Analyses between groups at different time points were performed using analysis of variance (ANOVA), with post hoc multiple comparison procedures. A comparison between the two groups was calculated using the student t-test. Statistical significance in inter-group differences was assessed at the 95% confidence level (p<0.05). Data are presented as mean ±standard errors of the mean (SEM). All comparisons we obtained using GraphPad Prism 7 (GraphPad Software, Inc., La Jolla, CA).
It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.
All publications mentioned herein (e.g. U.S. Patent Publication 20180104059) are incorporated herein by reference to disclose and describe aspects, methods and/or materials in connection with the cited publications.
1. A hydrogel composition, comprising:
2. The hydrogel composition of embodiment 1, further comprising deionized water.
3. The hydrogel composition of any one of embodiments 1-2, wherein the composition comprises from about 15% to about 25% of tantalum (w/w).
4. The hydrogel composition of any one of embodiments 1-3, wherein the composition comprises from about 17.5% to about 22.5% of tantalum (w/w).
5. The hydrogel composition of any one of embodiments 1-3, wherein the composition comprises about 15%, about 17.5%, about 20%, about 22.5% or about 25% of tantalum (w/w).
6. The hydrogel composition of any one of embodiments 1-5, wherein the composition comprises about 20% of tantalum (w/w).
7. The hydrogel composition of any one of embodiments 1-6, wherein the nanosilicate is a silicate nanoplatelet.
8. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises from about 2.5% to about 6% of nanosilicates (w/w).
9. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises from about 3.0% to about 4.0% of nanosilicates (w/w).
10. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises from about 3.25% to about 3.75% of nanosilicates (w/w).
11. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises from about 4.0% to about 5.5% of nanosilicates (w/w).
12. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises from about 4.25% to about 5.25% of nanosilicates (w/w).
13. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises from about 4.5% to about 5.0% of nanosilicates (w/w).
14. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises about 2.75%, about 3.0%, about 3.25%, about 3.5%, about 3.75%, 4.0%, about 4.25%, about 4.5%, about 4.75%, about 5.0%, about 5.25%, or about 5.5% of nanosilicates (w/w).
15. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises about 4.75% of nanosilicates (w/w).
16. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises about 4% of nanosilicates (w/w).
17. The hydrogel composition of any one of embodiments 1-7, wherein the composition comprises about 3.5% of nanosilicates (w/w).
18. The hydrogel composition of any one of embodiments 7-17, wherein the median diameter of the silicate nanoplatelet is from about 1 μm to about 15 μm.
19. The hydrogel composition of any one of embodiments 7-17, wherein the median diameter of the silicate nanoplatelet is from about 2 μm to about 5 μm.
20. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises from about 0.2% to about 1.2% of gelatin (w/w).
21. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises from about 0.6% to about 1.0% of gelatin (w/w), 22. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises from about 0.4% to about 0.8% of gelatin (w/w), 23. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1.0%, about 1.1%, or about 1.2% of gelatin (w/w).
24. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises about 0.6% of gelatin (w/w).
25. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises about 0.7% of gelatin (w/w).
26. The hydrogel composition of any one of embodiments 1-19, wherein the composition comprises about 0.8% of gelatin (w/w).
27. The hydrogel composition of any one of embodiments 1-26, wherein the viscosity of the composition decreases under a shear rate of about 10−1 1/s.
28. The hydrogel composition of any one of embodiments 1-27, wherein the composition has a displacement pressure of from about 15 kPa to about 45 kPa.
29. The hydrogel composition of any one of embodiments 1-28, wherein the composition is sterile.
30. A kit for use in the embolization of a blood vessel, comprising the hydrogel composition of any one of claims 1-29 packaged in a suitable container.
31. The kit of embodiment 30, wherein the suitable container is a syringe.
32. The kit of any one of embodiments 30-31, wherein the suitable container contains about 0.5 mL to about 5 mL of the hydrogel composition.
33. The kit of any one of embodiments 29-32, wherein the suitable container contains about 0.5 mL, about 1.0 mL, about 1.5 mL, about 2.0 mL, about 2.5 mL, about 3.0 mL, about 3.5 mL, about 4.0 mL, about 4.5 mL or about 5.0 mL of the hydrogel composition.
34. The kit of any one of embodiments 29-33, wherein the suitable container contains about 1.0 mL of the hydrogel composition.
35. A method for embolization of a blood vessel in a patient in need thereof, the method comprising administering a therapeutically effective amount of the hydrogel composition of any one of claims 1-29 to the patient's blood vessel.
36. The method of embodiment 35, wherein the maximum blood vessel size is about 3 mm.
37. The method of any one of embodiments 35-36, wherein the composition is administered to the blood vessel by injection through a catheter.
38. The method of any one of embodiments 35-37, wherein the blood vessel is a vessel of a hypervascularized tumor.
39. A method of embolizing a bleeding and/or hemorrhaging peripheral blood vessel in a patient in need thereof, the method comprising administering a therapeutically effective amount of the composition of any one of claims 1-29 to the patient's blood vessel.
40. The method of embodiment 39, wherein the maximum blood vessel size is about 3 mm.
41. The method of any one of embodiments 39-40, wherein the composition is administered to the blood vessel by injection through a catheter.
42. The method of any one of embodiments 35-41, further comprising visualizing the administration of the composition to the blood vessel by fluoroscopic visualization.
43. The method of any one of embodiments 35-41, further comprising determining the administration of the therapeutically effective amount of the composition by fluoroscopic visualization.
44. The method of any one of embodiments 35-43, wherein about 0.5 mL to about 5 mL of the composition is administered.
45. The method of any one of embodiments 35-44, wherein about 2 mL to about 5 mL of the composition is administered.
This application claims the benefit under 35 U.S.C. Section 119(e) of co-pending and commonly-assigned U.S. Provisional Patent Application Ser. No. 63/065,880, filed on Aug. 14, 2020, and entitled “METHODS AND MATERIALS FOR EMBOLIZATION” which application is incorporated by reference herein.
This invention was made with government support under HL137193 and HL140951 awarded by the National Institutes of Health. The government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US21/46154 | 8/16/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63065880 | Aug 2020 | US |
