WO2011031299A1 - Intrapericardial injections - Google Patents

Abstract

Compositions, biologies and methods for injection into or near the pericardial space are provided. In some embodiments, a sustained release vehicle is used to deliver an active agent in a controlled manner to treat the heart of a subject. The sustained release vehicle may be, for example, a hydrogel particle. In certain embodiments, a vehicle may be used to deliver an active agent comprising a biological entity such as a virus or cell to the pericardial space. In certain embodiments, compositions and methods are provided for inhibiting formation of tissue adhesions within the pericardial space.

Description

INTRAPERICARDIAL INJECTIONS

GOVERNMENT FUNDING

Research leading to various aspects of the present invention were sponsored, at least in part, by grants from the National Institutes of Health: R01 HL078731 ,

R01HL080498, R01HL083156, R01HL093183, R01HL088434, P20HL100396, and R21HL095980. The U.S. Government has certain rights in the invention.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Serial

No. 61/237,971, filed August 28, 2009, entitled "Intrapericardial Injections," by Ladage et al.

FIELD OF INVENTION

The present invention relates to biologies, compositions and methods for injection into the pericardial space.

BACKGROUND

One of the major challenges in the pharmacological treatment of heart diseases is to achieve delivery of suitable concentrations of therapeutic agents to the specific target site. Various approaches for local delivery to the heart include intramyocardial injections, epicardial deposition, and intracoronary or transvascular application. The efficacy of intramyocardial injection is limited by retention and survival rates of 2% or less. Epicardial deposition can be more effective, but is highly invasive. In the setting of vascular obstruction, such as myocardial infarction, reduced local blood supply can significantly impair targeted agent delivery via the vasculature.

The pericardium encloses the whole heart, creating a small and relatively isolated fluid filled compartment; for example in sheep the pericardial fluid volume is about 8 ml, with an estimated turnover time ranging from 5.4 to 7.2 hours. This enclosed space has been exploited for local delivery of a number of agents to the heart. For example, nitric oxide adenoviral-mediated gene transfer constructs and bFGF have been applied to the pericardial sac with single injections. The inventors have recognized in the context of the present invention that the development of a local, minimally invasive delivery system independent of the vascular status may offer an attractive alternative to existing delivery strategies, and that in certain circulstances prolonged delivery of agents to prevent tissue adhesion and/or bioactive agents, cells, etc. within the pericardial space might prove to be beneficial.

SUMMARY OF THE INVENTION

This invention relates generally to biologies, compositions and methods for delivery to the pericardial space of a patient. The subject matter of this invention involves, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of one or more systems and/or articles.

In one aspect, a method for treating the heart of a human or animal subject is provided. The method comprises injecting a polymer into the pericardial space of the subject, wherein the polymer prevents adhesion from forming between a first tissue and a second tissue in the pericardial space.

In another aspect, a method for treating the heart of a human or animal subject is provided. The method comprises injecting a plurality of particles comprising gelatin into the pericardial space of the subject, wherein the particles further comprise an active agent and are configured to act as a sustained release vehicle for the active agent.

In yet another aspect, a method for treating the heart of a human or animal subject is provided. The method comprises injecting a plurality of particles having an average particle size, corresponding to the 50% point in the weight distribution of particles, greater than 500 microns into the pericardial space of the subject, wherein the particles further comprise an active agent and are configured to act as a sustained release vehicle for the active agent.

In still another aspect, a method for treating the heart of a human or animal subject is provided. The method comprises injecting a polymer comprising a virus or cell into the pericardial space of a subject.

The subject matter of this application may involve, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of a single system or article.

The present invention also relates to pharmaceutical compositions comprising any of the compositions and/or particles described above and herein, as well as one or more pharmaceutically acceptable carriers, additives, and/or diluents. The present invention also relates to compositions for treating a subject having a heart disease or cardiovascular condition, wherein the composition comprises any of the compositions and/or particles described above and herein. The present invention also relates to the use of any of the compositions and/or particles described above and herein in the preparation of a medicament for treating a subject having a heart disease or cardiovascular condition.

Other aspects, embodiments and features of the invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings. All patent applications and patents incorporated herein by reference are incorporated by reference in their entirety. In case of conflict, this specification, including definitions, will control.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are schematic and are not intended to be drawn to scale. In the figures, each identical, or substantially similar component that is illustrated in various figures is typically represented by a single numeral or notation. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In the drawings:

FIG. 1 shows a schematic of a heart and pericardium;

FIGs. 2A-2E are photocopies showing various images (FIGs. 2A and 2C-2E) and a plot (FIG. 2B) demonstrating the reabsorption time of particles, according to one set of embodiments;

FIG. 3A shows an image of a gelfoam particle, according to an embodiment;

FIG. 3B shows a graph of dissolution times;

FIG. 3C are photocopies of an image of mesenchymal stem cells within a 3-D scaffold of gelfoam fibers in a cell culture dish, according to an embodiment;

FIG. 3D shows a schematic of an injection technique, according to an

embodiment;

FIG. 4A shows fluoroscopic images of catheter insertion, according to an embodiment; FIG. 4B shows fluoroscopic images of liquid dye, gelfoam mixed with dye, and liquid dye after closure of the puncture site to assess possible leakage, according to an embodiment;

FIG. 4C shows the position of the injected gelfoam as well as the IVUS probe in relation to the infarct zone, according to an embodiment;

FIGs. 5A-5C show various images and a plot (FIG 5C) demonstrating assessment of the size of the space between the heart and the pericardial membrane, according to an embodiment;

FIGs. 6A are photocopies of fluorescent microscopy images demonstrating the engraftment of eGFP labeled mesenchymal stem cells in the peri infarct area and scar, according to an embodiment;

FIG. 6B shows gel electrophoresis images of PCR results, according to an embodiment; and

FIG. 6C are photocopies of fluorescent microscopy images of eGFP transfection, according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to biologies, compositions and methods for injection into the pericardial space. In some embodiments, the invention utilizes a sustained release vehicle to deliver an agent in a controlled manner to treat the heart of a subject. The sustained release vehicle may be, for example, a hydrogel particle. In other embodiments, a vehicle may be used to deliver a biological entity such as a virus or cell to the pericardial space. In certain embodiments, compositions and methods are also provided for inhibiting formation of tissue adhesions near or within the pericardial space.

Upon injury, adult human hearts respond by producing fibrotic tissue. For example, myocardial infarction typically results in loss of cardiomyocytes and replacement of these cells with scar tissue. Scar tissue that connects tissue surfaces that are normally separated are known as adhesions and can cause significant complications for a patient. Agents that can cause regeneration of cardiomyocytes are therefore in great need as are compositions and methods for delivering such agents effectively, in a sustained fashion, and without causing further damage to the heart.

The pericardial space offers a convenient location for sustained delivery of an agent to the heart because of its proximity to the myocardium. The substantially closed volume of the pericardial sac also offers the benefit of localized containment of an agent and accessibility by minimally invasive techniques (i.e., injection).

Certain existing techniques for delivering agents to the heart in the pericardial space are deficient in that the delivery materials can cause adhesions to form, which can cause complications in the patient. Furthermore, certain controlled delivery devices implanted by open surgical methods may require more recovery time for the patient and can also lead to adhesion formation. Thus, an aim of certain embodiments described herein is to provide a sustained release vehicle that can be implanted using a minimally invasive technique. Another aim is to provide a composition and/or technique that minimizes or prevents adhesions.

Advantageously, compositions and methods of the invention can be used to treat a variety of diseases or bodily conditions. For example, the biologies, compositions and methods may be used to prevent the onset, slow progression, and/or reduce symptoms of cardiac disease caused by, for example, myocardial ischemia, hypoxia, stroke, myocardial infarction, etc. Other examples of diseases or bodily conditions that can be treated using the inventive compositions and methods are provided below.

FIG. 1 shows a schematic of a heart 100, which includes an aorta 110, a superior vena cava 112, a pulmonary artery 114, a myocardium 120, an epicardium (also known as the visceral pericardium) 130, and a pericardium (also known as the parietal pericardium) 140. Heart 100 also includes a pericardial space 150, a region between the epicardium 130 and the pericardium 140. The pericardial space may contain a pericardial fluid. The pericardium envelopes the heart and a portion of the great vessels (i.e., the aorta, superior vena cava, and pulmonary artery).

In some embodiments, a method of treating the heart of a human or animal subject involves introducing a polymer into or near pericardial space 150 of the subject. The polymer may be introduced into or near the pericardial space of the subject by any suitable method such as by injection or by implantation of a device, as described in more detail below. The delivery technique used may be minimally-invasive. In some cases, the polymer is delivered locally to a site of injury (e.g., an infarction), the location of which may be determined by any suitable method (e.g., by echocardiography or by cardiac MRI). The polymer may be in any suitable form while or after being introduced into the subject. For example, in one embodiment the polymer is in the form of a liquid or a gel that can be injected into the subject. After injection, the liquid or gel may remain in a liquid or gel form, respectively, or in other embodiments may solidify after being introduced into the subject. In another embodiment, the polymer may be in solid form while being introduced into the subject. The polymer may remain as a solid after being introduced into the subject, or may become a liquid or a gel, e.g., by chemical reaction orphysical interaction with one or more components delivered along with the polymer, or by interaction with one or more components already present at the place of injection. As described in more detail below, the polymer may be in the form of a plurality of particles in some embodiments.

In some instances, the polymer (e.g., in particulate or other form) becomes substantially immobilized in or near the pericardial space after injection. For example, the polymer may be held in a localized region between pericardium 140 and myocardium 120 (e.g., in pericardial space 150, at or near the parietal pericardium 140 and/or epicardium 130, between the parietal pericardium and the myocardium, or between the pericardium and a heart vessel (e.g., aorta 110, superior vena cava 112, or pulmonary artery 114)). In certain cases, the polymer forms a gel or a solid mass that localizes at a particular region within the pericardial space, such as those noted above. For instance, the polymer may form a membrane or a film on a surface of the pericardium (e.g., the parietal pericardium or the visceral pericardium). In some cases, the membrane or film forms at a site of injury to be treated by the composition and methods described herein (e.g., at a site of infarction). In other embodiments, the polymer may at least partially distribute within the pericardial space after injection. For example, the polymer may be dispersed or suspended in the pericardial fluid. Advantageously, as described in more detail below, the polymer may include an active agent that can be delivered to one or more locations within the heart.

Polymers described herein (e.g., in particulate or other form) may have desirable properties, such as the ability to substantially inhibit or reduce tissue adhesion formation. For example, the polymer may be injected into the pericardial space and may

substantially prevent adhesion between a first tissue and a second tissue near or within the pericardial space. The first tissue and the second tissue may be the same (i.e., the first tissue and the second tissue may be different regions of the pericardium) or different (i.e., the first tissue may be the pericardium and the second tissue may be the

myocardium). In certain embodiments, tissue adhesion formation is substantially inhibited or reduced between the parietal pericardium and the visceral pericardium, between the parietal pericardium and the myocardium, or between the pericardium and a heart vessel. It should be understood that tissue adhesion formation can be substantially inhibited or reduced between other tissues or layers within or near the pericardial space. Sometimes, the polymer can substantially prevent or reduce tissue adhesions between a tissue of the heart and a tissue of another organ (e.g., lung tissue). Furthermore, in some cases the polymer can substantially prevent or reduce the amount of scar tissue formed at a tissue site.

It has been discovered within the context of the invention that certain forms of a polymer can reduce or substantially prevent tissue adhesion and/or scar formation compared to other forms of the same polymer, all other factors being equal. For example, it has been found that polymers in certain particulate forms reduce tissue adhesion and/or scar formation to a greater extent than the same polymer delivered in a patch form. Formation of tissue adhesion and/or scar formation may be reduced by, for example, at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, or at least 90%, when delivered in a particulate form compared to a non-particulate form (e.g., in the form of a patch), all other factors being equal.

In other embodiments, formation of tissue adhesions and/or scar tissue is reduced by at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, or at least 90%, when the polymer is delivered by injection, compared to when the polymer is delivered by a non-injection method (e.g., by surgical insertion), all other factors being equal. In other embodiments, formation of tissue adhesions and/or scar formation is reduced by at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, or at least 90%, by injecting a polymer into or near the pericardial space of the subject compared to not delivering any polymer into or near the pericardial space.

The amount of tissue adhesions and/or scar tissue formation can be determined by one of ordinary skill in the art by gross inspection and/or by methods such as tissue staining, echocardiography, and cardiac MRI.

Accordingly, in one set of embodiments, a method for treating the heart of a human or animal subject includes injecting a polymer into the pericardial space of the subject, and preventing or reducing the formation of adhesion between a first tissue and a second tissue in or near the pericardial space. The polymer, which may be in particulate or other form, may reduce the amount of adhesion between the first and second tissues in or near the pericardial space by at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, or at least 90% compared to either the absence of such delivery, or compared to a different method of delivery (e.g., a non-injection method).

As described herein, in some embodiments, a method of treating the heart of a human or animal subject comprises injecting a plurality of particles. The particles may be configured for controlled release of an active agent and may have other desirable properties such as the ability to inhibit tissue adhesion. The particles may be any suitable size. For example, in some cases the particles may have an average particle size greater than 50 nm, greater than 200 nm, greater than 500 nm, greater than 10 microns, greater than 100 microns, greater than 500 microns, greater than 1 mm, greater than 2 mm, etc. In some cases, the particles have an average particle size between 500 microns and 2mm (e.g., between 500 microns and 1 mm, or between 1 mm and 2 mm) or in other cases between about 1mm and 4mm. The particle size may be chosen to elicit certain properties (i.e., release rate of an agent, degradation rate, agent loading capacity, etc.) or accommodate certain methods of administration (i.e., injection), as discussed in more detail below. As used herein, "particle size" refers to the largest characteristic dimension (i.e. of a line passing through the geometric center of the particle e.g., diameter) that can be measured along any orientation of a particle (e.g., a polymer particle). In the case of hydrogel particles, particle size refers to the size of the swelled particle (e.g., in a solution). Particle size as used herein may be measured or estimated, for example, using a sieve analysis, wherein particles are passed through openings of a standard size in a screen. The particle-size distribution may be reported as the weight percentage of particles retained on each of a series of standard sieves of decreasing size, and the percentage of particles passed of the finest size. That is, the average particle size may correspond to the 50% point in the weight distribution of particles.

Furthermore, the particles may have any suitable shape. For example, they may be substantially spherical, pyramidal, cubical, rod-like, or irregularly shaped.

After a plurality of particles are introduced into the pericardial space of a subject, the particles may remain in particulate form. For example, the particles may be suspended or dispersed within the pericardial fluid. In some embodiments, the particles aggregate with one another to form a solid or gel-like mass. In other embodiments, the particles dissolve or degrade after being delivered to the subject. In yet other embodiments, the particles form a film or membrane of material on a tissue surface at or near the site of delivery, or at or near a site of injury. Such a film may, in some cases, extend between two different surfaces at the site of delivery. The film may have any suitable thickness, e.g., between 0.1-5 microns thick, between 5-10 microns thick, between 10-50 microns thick, between 50-100 microns thick, between 100-200 microns thick, between 200-500 microns thick, between 0.5-1 mm thick, or between 1-2 mm thick. The film may be elastic or inelastic, e.g., depending on the polymer used.

A particle or other delivery agent may be contructed of any suitable material. In some embodiments, a particle or delivery agent comprises a polymer. For example, the polymer may be a biodegradable polymer such as a polyester (i.e., polylactic acid, polyglycolic acid, polycaprolactone, etc.), polyanhydride, polycarbonate, copolymers thereof, etc. In some cases, the polymer may form a hydrogel. Examples of polymers capable of forming hydrogels include gelatin (i.e., Gelfoam®, commercially available from Pfizer, Inc.), hyaluronic acid, chitosan, alginate, agarose, polyethylene glycol- polypropylene glycol copolymers, etc. A polymer may be crosslinked, for example through covalent bonds, ionic bonds, hydrophobic bonds, metal binding, etc. A polymer may be obtained from natural sources or be created synthetically.

In other embodiments, the particle is non-biodegradable, or is degradable only after application of energy from an external source (e.g., light or heat).

Those of ordinary skill in the art can chose appropriate materials to control the rates of degradation of the material after it has been delivered to the subject. For instance, the polymer in a particulate or other form may substantially or completely degrade within the subject after or within at least one day, at least three days, at least one week, at least two weeks, at least one month, at least six months, or at least one year. The rate of degradation will depend on the condition to be treated among other factors.

In some embodiments, a polymer may be modified to improve one or more properties. For example, a polymer may be crosslinked or at least partially degraded, or an existing crosslinking density may be increased or descreased. Such changes may be advantageous, for instance, for changing the degradation time of the polymer or the rate of release of an agent from the polymer.

The polymer may be a homopolymer or a copolymer. In certain embodiments, the polymer is a diblock copolymer, a triblock copolymer, etc., e.g., where one block is a hydrophobic polymer and another block is a hydrophilic polymer, or where both blocks are hydrophilic or both block are hydrophobic. For example, the polymer may be a copolymer of an a-hydroxy acid (e.g., lactic acid) and polyethylene glycol. In some cases, a particle includes a hydrophobic polymer, such as polymers that may include certain acrylics, amides and imides, carbonates, dienes, esters, ethers, fluorocarbons, olefins, sytrenes, vinyl acetals, vinyl and vinylidene chlorides, vinyl esters, vinyl ethers and ketones, and vinylpyridine and vinylpyrrolidones polymers. In other cases, a particle includes a hydrophilic polymer, such as polymers including certain acrylics, amines, ethers, styrenes, vinyl acids, and vinyl alcohols. The polymer may be charged or uncharged. As noted herein, the particular components of the particle can be chosen so as to impart certain functionality to the structures.

In some embodiments, the particles may swell upon absorption of fluid. This effect may be used, for example, to load the particles with an active agent, as discussed in more detail below. As discussed above, in certain embodiments, the particles may be hydrogels. A short description of the properties and behavior of certain hydrogels is provided below. It should be noted that the list is not exhaustive, and those of ordinary skill in the art may readily select or form other suitable absorbent materials using available information regarding the absorbency and swelling properties of various materials and no more than routine experimentation and screening tests.

Polymer gels are typically characterized by long chain polymer molecules that are crosslinked to form a network. This network can trap and hold fluid, which can give gels properties somewhere between those of solids and liquids. Depending on the level of crosslinking, various properties of a particular gel can be tailored. For example, a highly crosslinked gel generally is structurally strong and tends to resist releasing fluid under pressure, but may exhibit slow transition times. A lightly crosslinked gel may be weaker structurally, but may react more quickly during its phase transition. In the design of gels for a particular application, the degree of crosslinking may be adjusted to achieve the desired compromise between speed of absorption and level of structural integrity. Those of ordinary skill in the art would be able to identify methods for modulating the degree of crosslinking in such gels.

Particles may be made by any suitable method. In some embodiments, particles may be made by rasping a larger piece of polymeric material. For example, a Gelfoam® patch may be rasped into particles. In some cases, particles may be made by oiHn-water emulsion techniques, crosslinking of polymers, etc. Other methods for fabricating particles will be known to those of ordinary skill in the art.

The biologies, compositions and methods disclosed herein may be used to treat a variety of diseases and/or conditions, for example: cardiac arrhythmia, congenital heart diseases, dilated cardiomyopathy, hypertrophic cardiomyopathy, aortic regurgitation, aortic stenosis, mitral regurgitation, mitral stenosis, Ellis-van Cleveld syndrome, familial hypertrophic cardiomyopathy, Holt-Orams syndrome, Marfan syndrome, Ward-Romano syndrome, pericarditis, myocarditis, tumors of the heart (e.g., myxoma, metastasis, etc.), atherosclerosis, hypertension, etc.

In some cases, the biologies, compositions and methods described herein can reduce the amount of pericardial effusions (i.e., abnormal amounts of accumulated fluid in the pericardial cavity). For example, a delivery method may include removal of an amount of pericardial fluid prior to delivery of a composition described herein, and then delivery of the same or similar amount of volume of the composition. After delivery, the amount of fluid in the pericardial may be maintained at normal amounts (e.g., about 15 - about 50 mL).

Furthermore, biologies, compositions and methods described herein may facilitate healing in a subject, and therefore may be employed during or after after surgery, tissue grafting, organ or tissue transplant, or treatment of heart disease or a cardiovascular condition. The biologies, compositions and methods may modify or reduce scar tissue, promote generation of new tissue, preserve the viability of impaired tissues (e.g., ischemic tissue), or prevent or reduce adhesions.

As described herein, a polymer or composition may be configured to release an active agent. In some embodiments, the polymer may form a particle with a core-shell configuration, where the shell comprises a polymer and the core may contain, for example, an active agent. In other embodiments, a particle may be substantially uniform throughout. In some embodiments, a polymer may be loaded with an active agent. The active agent may be selected from organic compounds, inorganic compounds, proteins, nucleic acids, carbohydrates, cells, viruses, etc. In some cases, the active agent may be a pharmaceutical agent. In certain instances, the pharmaceutical agent may be used to treat the heart. Suitable drugs include, but are not limited to, growth factors, angiogenic agents, calcium channel blockers, antihypertensive agents, inotropic agents,

antiatherogenic agents, anti-coagulants, beta-blockers, anti-arrhythmia agents, vasodilators, thrombolytic agents, cardiac glycosides, anti-inflammatory agents, antibiotics, antiviral agents, antifungal agents, agents that inhibit protozoan infections, antineoplastic agents, and steroids.

Angiogenic factors include, but are not limited to, a fibroblast growth factor, e.g., basic fibroblast growth factor (bFGF), and acidic fibroblast growth factor, e.g., FGF-1, FGF-2, FGF-3, FGF-4, recombinant human FGF; a vascular endothelial cell growth factor (VEGF), including, but not limited to, VEGF-1, VEGF-2, VEGF-D; transforming growth factor-alpha; transforming growth factor-beta; platelet derived growth factor; an endothelial mitogenic growth factor; platelet activating factor; tumor necrosis factor- alpha; angiogenin; a prostaglandin, including, but not limited to PGEi, PGE₂; placental growth factor; GCSF (granulocyte colony stimulating factor); HGF (hepatocyte growth factor); IL-8; vascular permeability factor; epidermal growth factor; substance P;

bradykinin; angiogenin; angiotensin II; proliferin; insulin like growth factor- 1 ;

nicotinamide; a stimulator of nitric oxide synthase; estrogen, including, but not limited to, estradiol (E2), estriol (E3), and 17-beta estradiol; and the like. Angiogenic factors further include functional analogs and derivatives of any of the aforementioned angiogenic factors. Derivatives include polypeptide angiogenic factors having an amino acid sequence that differs from the native or wild-type amino acid sequence, including conservative amino acid differences (e.g., serine/threonine, asparagine/glutamine, alanine/valine, leucine/isoleucine, phenylalanine/tryptophan, lysine/arginine, aspartic acid/glutamic acid substitutions); truncations; insertions; deletions; and the like, that do not substantially adversely affect, and that may increase, the angiogenic property of the angiogenic factor. Angiogenic factors include factors modified by polyethylene glycol modifications ("PEGylation"); acylation; acetylation; glycosylation; and the like. An angiogenic factor may also be a polynucleotide that encodes the polypeptide angiogenic factor. Such a polynucleotide may be a naked polynucleotide or may be incorporated into a vector, such as a viral vector system such as an adenovirus, adeno-associated virus or lentivirus systems.

Calcium channel blockers include, but are not limited to, dihydropyridines such as nifedipine, nicardipine, nimodipine, and the like; benzothiazepines such as dilitazem; phenylalkylamines such as verapamil; diarylaminopropylamine ethers such as bepridil; and benzimidole-substituted tetralines such as mibefradil.

Antihypertensive agents include, but are not limited to, diuretics, including thiazides such as hydroclorothiazide, furosemide, spironolactone, triamterene, and amiloride; antiadrenergic agents, including clonidine, guanabenz, guanfacine, methyldopa, trimethaphan, reserpine, guanethidine, guanadrel, phentolamine, phenoxybenzamine, prazosin, terazosin, doxazosin, propanolol, methoprolol, nadolol, atenolol, timolol, betaxolol, carteolol, pindolol, acebutolol, labetalol; vasodilators, including hydralizine, minoxidil, diazoxide, nitroprusside; and angiotensin converting enzyme inhibitors, including captopril, benazepril, enalapril, enalaprilat, fosinopril, lisinopril, quinapril, ramipril; angiotensin receptor antagonists, such as losartan; and calcium channel antagonists, including nifedine, amlodipine, felodipine XL, isadipine, nicardipine, benzothiazepines (e.g., diltiazem), and phenylalkylamines (e.g. verapamil).

Anti-coagulants include, but are not limited to, heparin; warfarin; hirudin; tick anti-coagulant peptide; low molecular weight heparins such as enoxaparin, dalteparin, and ardeparin; ticlopidine; danaparoid; argatroban; abciximab; and tirofiban.

Anti-arrhythmic drugs may be local anesthetics, beta-receptor blockers, prolongers of action potential duration or calcium antagonism. Antiarrhythmic agents include, but are not necessarily limited to, sodium channel blockers (e.g., lidocaine, sotatol, procainamide, encainide, flecanide, and the like), beta adrenergic blockers (e.g., propranolol, dopamine-beta-hydroxylase inhibitors), prolongers of the action potential duration (e.g., amiodarone), and calcium channel blockers (e.g., verpamil, diltiazem, nickel chloride, and the like). Delivery of cardiac depressants (e.g., lidocaine), cardiac stimulants (e.g., isoproterenol, dopamine, norepinephrine, etc.), and combinations of multiple cardiac agents (e.g., digoxin/quinidine to treat atrial fibrillation) is also of interest.

Agents to treat congestive heart failure, include, but are not limited to, a cardiac glycoside, a loop diuretic, a thiazide diuretic, a potassium ion sparing diuretic, an angiotensin converting enzyme inhibitor, an angiotension receptor antagonist, a nitrovasodilator, a phosphodiesterase inhibitor, a direct vasodilator, an alpha i -adrenergic receptor antagonist, a calcium channel blocker, and a sympathomimetic agent.

Thrombolytic agents include, but are not limited to, urokinase plasminogen activator, urokinase, streptokinase, inhibitors of alpha2-plasmin inhibitor, inhibitors of plasminogen activator inhibitor- 1, angiotensin converting enzyme (ACE) inhibitors, spironolactone, tissue plasminogen activator (tPA), inhibitors of interleukin lbeta converting enzyme, anti-thrombin III, and the like.

Agents suitable for treating cardiomyopathies include, but are not limited to, dopamine, epinephrine, norepinephrine, and phenylephrine.

Anti-inflammatory agents include, but are not limited to, any known non-steroidal anti-inflammatory agent, and any known steroidal anti-inflammatory agent.

Antimicrobial agents include antibiotics (e.g. antibacterial), antiviral agents, antifungal agents, and anti-protozoan agents.

Antineoplastic agents include, but are not limited to, those which are suitable for treating cardiac tumors (e.g., myxoma, lipoma, papillary fibroelastoma, rhabdomyoma, fibroma, hemangioma, teratoma, mesothelioma of the AV node, sarcomas, lymphoma, and tumors that metastasize to the heart) including cancer chemotherapeutic agents, a variety of which are well known in the art.

In some embodiments, a polymer may be loaded with an active agent by soaking the polymer in a solution containing the agent. Generally, the loading of agent can be increased by increasing the concentration of the agent in the soaking solution and/or increasing the contact time between the polymer and the soaking solution. In some cases, the polymer is in the form of a particle, and the agent may diffuse into the particle. An agent may also adsorb onto the surface of the particle. The association of an agent with a polymer may result from non-covalent interactions. Alternatively, an agent may be reacted with a polymer to form a covalent bond. As known to those in the art, an agent- polymer covalent bond may be chosen such that under certain conditions (i.e.,

physiological conditions), the bond may break thereby releasing the agent. Depending on the ratio of the active agent to polymer, the nature of the particular polymer employed, the type of association between the active agent and the particle, and the size of the particle, the rate of release of the active agent can be controlled.

In some embodiments, an active agent comprising a virus and/or cell may be delivered using a polymer. The polymer may be configured such that the virus and/or cell can be released in sustained fashion. In some cases, a virus and/or cell and one or more pharmaceutical agents may be delivered. For example, in some embodiments, a virus and/or cell may be co-delivered with one or more pharmaceutical agents (i.e., in the same injection). In another embodiment, a virus and/or cell may be delivered by a first injection and one or more pharmaceutical agents may be delivered to essentially the same or a different region by a second injection. In some cases, a virus and/or cell may be delivered before, after, or essentially simultaneously with one or more pharmaceutical agents.

In some cases, a transfection vector (e.g., a virus, nanoparticle, and/or the like) may be used for gene delivery. Gene delivery may be beneficial, for example, for transforming non-proliferative cells into proliferative cells (i.e., for regeneration of heart tissue). Examples of viruses potentially useful for gene delivery include double-stranded DNA viruses, single-stranded DNA viruses, double-stranded RNA viruses and single- stranded RNA viruses. Examples of double-stranded DNA viruses include, but are not limited to, Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpes simplex virus- 1 (HSV-1), HSV-2, varicella-zoster virus (VZV), human herpes virus-6 (HHV-6), HHV-7, HHV-8, poxvirusm, and adenovirus. Examples of single-stranded DNA viruses include, but are not limited to, parvovirus. Examples of double-stranded RNA viruses include, but are not limited to, retroviruses and reoviruses. Examples of single-stranded RNA viruses include, but are not limited to, paramyxoviruses, myxoviruses, and flaviviruses.

In some embodiments, a human or animal subject may show evidence of transfection of cardiac tissue following delivery of a vector. For example, in some cases, a human or animal subject may show evidence of transfection of cardiac tissue after a period of at least 3 days after delivery, in certain embodiments at least 1 week after delivery, in certain embodiments at least 2 weeks after delivery, in certain embodiments at least 3 weeks after delivery, in certain embodiments at least 4 weeks after delivery, in certain embodiments at least 8 weeks after delivery, and in certain embodiments at least 20 weeks after delivery.

A cell may be used, in some instances, as an active agent factory. For example, a cell (e.g., a stem cell) may secrete a growth factor or other agent that has therapeutic value. By delivering such cells to the pericardial space, these cells may continuously generate and deliver a therapeutic. In other examples, a cell may be used to regenerate cardiac tissue. For instance, stem cells may be delivered to the pericardial space and may differentiate to form new cardiac tissue. Examples of stem cells potentially useful in the context of the invention include, but are not limited to, totipotent, pluripotent, multipotent and/or unipotent stem cells. Examples of differentiated or undifferentiated stem cells and progenitor cells useful or potential useful within the context of the invention include, but are not limited to, cardiac stem cells, bone marrow stem cells, epidermal stem cells, hematopoietic stem cells, embryonic stem cells, mesenchymal stem cells, epithelial stem cells, gut stem cells, skin stem cells, neural stem cells, liver progenitor cells, endocrine progenitor cells, and lympho-hematopoietic stem cells. Stem cells can be derived from a variety of sources including, but not limited to, bone marrow, mobilized or unmobilized peripheral blood, umbilical cord blood, fetal liver tissue, other organ tissue, skin, and nerve tissue.

In some embodiments, cells delivered to the pericardial space may integrate with the host tissue. In some cases, the cells may proliferate. In some instances, a stem cell delivered to the pericardial space may differentiate into a mature cell. In some embodiments, a human or animal subject may show evidence of engraftment of a delivered cell after a period of time. For example, in some cases, a human or animal subject may show evidence of engraftment of a delivered cell after a period of at least 3 days after injection, in certain embodiments at least 1 week after injection, in certain embodiments at least 2 weeks after injection, in certain embodiments at least 3 weeks after injection, in certain embodiments at least 4 weeks after injection, in certain embodiments at least 8 weeks after injection, and in certain embodiments at least 20 weeks after delivery.

In some embodiments, a cell may be grown on a polymer prior to delivery to the pericardial space. For example, cells may be seeded on a polymer and cultured for a period of time to allow attachment of the cells. In some instances, cells may be cultured on a polymer for at least 30 minutes, in certain embodiments at least 1 hour, in certain embodiments at least 2 hours, in certain embodiments at least 4 hours, in certain embodiments at least 8 hours, in certain embodiments at least 24 hours, and in certain embodiments at least 1 week.

The polymers and particles described herein may be used in "pharmaceutical compositions" or "pharmaceutically acceptable" compositions, which comprise a therapeutically effective amount of an active agent associated with one or more of the polymers or particles described herein, formulated together with one or more

pharmaceutically acceptable carriers, additives, and/or diluents. The pharmaceutical compositions described herein may be useful for diagnosing, preventing, treating or managing a disease or bodily condition including cardiac and certain vascular conditions.

The pharmaceutical compositions may be specially formulated for administration in gel or liquid form, including those adapted for the following: a sterile solution or suspension, a sustained-release formulation, or as a cream or foam. In some cases, a composition includes a plurality of particles encapsulated in a hydrogel or hydrogel precursor and injected into the pericardial space. The hydrogel or hydrogel precursor may be able to inhibit the formation of tissue adhesions.

The phrase "pharmaceutically acceptable" is employed herein to refer to those structures, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

The phrase "pharmaceutically-acceptable carrier" as used herein means a pharmaceutically-acceptable material, composition or vehicle, such as a liquid, gel or solid filler, diluent, excipient, or solvent encapsulating material, involved in carrying or transporting the subject compound, e.g., from a device or from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. Some examples of materials which can serve as

pharmaceutically-acceptable carriers include: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol; pH buffered solutions; polyesters, polycarbonates and/or polyanhydrides; and other non-toxic compatible substances employed in pharmaceutical formulations.

Examples of pharmaceutically-acceptable antioxidants include: water soluble antioxidants, such as ascorbic acid, cysteine hydrochloride, sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; oil-soluble antioxidants, such as ascorbyl palmitate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propyl gallate, alpha-tocopherol, and the like; and metal chelating agents, such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol, tartaric acid, phosphoric acid, and the like.

The amount of active agent which can be combined with a particle or other carrier material to produce a single dosage form will vary depending upon the host being treated, and the particular mode of administration. The amount of active agent that can be combined with a particle or other carrier material to produce a single dosage form will generally be that amount of the compound which produces a therapeutic effect.

Generally, this amount will range from about 1% to about 99% of active ingredient, from about 5% to about 70%, or from about 10% to about 30%.

Polymers and particles described herein suitable for injection may be

administered in the form of a solution, dispersion, or a suspension in an aqueous or nonaqueous liquid, as an emulsion or microemulsion (e.g., an oil-in-water or water-in-oil liquid emulsion), or as an elixir or syrup, or as pastilles (using an inert base, such as gelatin and glycerin, or sucrose and acacia), each containing a predetermined amount of a particle described herein, and optionally including an active ingredient.

Examples of suitable aqueous and nonaqueous carriers, which may be employed in the pharmaceutical compositions described herein include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants. In addition to the polymers and/or particles, a liquid dosage form may contain inert diluents commonly used in the art, such as, for example, water or other solvents, solubilizing agents and emulsifiers, such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1 ,3-butylene glycol, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof.

Suspensions, in addition to the polymers and/or particles, may contain suspending agents as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, and mixtures thereof.

These compositions and particles described herein may also contain adjuvants such as preservatives, wetting agents, emulsifying agents, lubricating agents and dispersing agents. Prevention of the action of microorganisms upon the particles may be facilitated by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like into the

compositions. In addition, prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents which delay absorption such as aluminum monostearate and gelatin.

Delivery systems suitable for use with polymers, particles and compositions described herein include time-release, delayed release, sustained release, or controlled release delivery systems. Such systems may avoid repeated administrations of the particles and/or active agents in many cases, increasing convenience to the subject and the physician. Many types of release delivery systems are available and known to those of ordinary skill in the art. Specific examples include, but are not limited to, erosional systems in which the composition is contained in a form within a matrix, or diffusional systems in which an active component controls the release rate. The compositions may be as, for example, particles (e.g., microparticles, microspheres), hydrogels, polymeric reservoirs, or combinations thereof. In some embodiments, the system may allow sustained or controlled release of an active agent to occur, for example, through control of the diffusion or erosion/degradation rate of the formulation or particle. The polymers, particles and compositions described herein can also be combined (e.g., contained) with delivery devices such as syringes, catheters, tubes, and implantable devices.

In some embodiments, a pericardial injection (e.g., using a catheter and injection needle) may be used to deliver the polymers, particles, biologies and compositions described. A non-limiting schematic of such an approach is shown in FIG. 4. In some cases, it may be desirable to use a guiding instrument to guide insertion of a catheter and/or needle. For example, in some embodiments, a fluoroscope may be used to guide insertion of the catheter and/or needle. In another embodiment, ultrasound may be used. For example, in some cases, intravascular ultrasound (IVUS) may be used. In one embodiment, an IVUS probe may be advanced after the subxiphoid access and positioned next to the pericardial sac at the proposed puncture site. The ultrasound probe may be used to produce a real-time picture so as to inspect the size of the space between the heart and the pericardial membrane in the diastole and systole. This may be advantageous, in some cases, since the distance between the heart and the pericardial membrane can become altered from post-infarction effusion or adhesion. In some cases, use of a guiding instrument may allow more precise positioning of the catheter over the anterior wall of the LV before injection of the polymers, particles, biologies and compositions described ^®.

In some instances, the puncture site for the pericardial injection may be closed, for example, to prevent leakage of the injected material. For instance, an injection procedure may be performed and a Starclose SE vascular closure device (Abbott, Abbott Park, IL) may be used to seal the pericardium. In some embodiments, closing the puncture site may result in less than 20% leakage of injected material, less than 10% leakage of injected material, less than 5% leakage of injected material, less than 1% leakage of injected material, or essentially no leakage of injected material,

Use of a long-term release implant may be particularly suitable in some cases. "Long-term release," as used herein, means that the implant is constructed and arranged to deliver therapeutic levels of the composition for at least about 30 or about 45 days, for at least about 60 or about 90 days, or even longer in some cases. Long-term release implants are well known to those of ordinary skill in the art. In some embodiments, a long-term release implant can be formed by delivering a plurality of particles to a subject, after which the particles remain within the subject for an extended period. When the particles described herein are administered as pharmaceuticals, to humans and animals, they can be given per se or as a pharmaceutical composition containing, for example, about 0.1% to about 99.5%, about 0.5% to about 90%, or the like, of particles in combination with a pharmaceutically acceptable carrier.

The particles and compositions described herein may be given in dosages, e.g., at the maximum amount while avoiding or minimizing any potentially detrimental side effects. The particles and compositions can be administered in effective amounts, alone or in a combinations with other compounds. For example, when treating cancer, a composition may include the structures described herein and a cocktail of other compounds that can be used to treat cancer.

The phrase "therapeutically effective amount" as used herein means that amount of a material or composition comprising an inventive structure which is effective for producing some desired therapeutic effect in a subject at a reasonable benefit/risk ratio applicable to any medical treatment. Accordingly, a therapeutically effective amount may, for example, prevent, minimize, or reverse disease progression associated with a disease or bodily condition. Disease progression can be monitored by clinical observations, laboratory and imaging investigations apparent to a person skilled in the art. A therapeutically effective amount can be an amount that is effective in a single dose or an amount that is effective as part of a multi-dose therapy, for example an amount that is administered in two or more doses or an amount that is administered chronically.

The effective amount of any one or more particles or an active agent therein described herein may be from about 10 ng/kg of body weight to about 1000 mg/kg of body weight, and the frequency of administration may range from once a day to a once a month basis, to an as-needed basis. However, other dosage amounts and frequencies also may be used as the invention is not limited in this respect. A subject may be

administered one or more particles described herein in an amount effective to treat one or more diseases or bodily conditions described herein.

The effective amounts will depend on factors such as the severity of the condition being treated; individual patient parameters including age, physical condition, size and weight; concurrent treatments; the frequency of treatment; or the mode of administration. These factors are well known to those of ordinary skill in the art and can be addressed with no more than routine experimentation. In some cases, a maximum dose be used, that is, the highest safe dose according to sound medical judgment.

The selected dosage level can also depend upon a variety of factors including the activity of the particular inventive structure employed, the route of administration, the time of administration, the rate of excretion or metabolism of the particular particles or active agents being employed, the duration of the treatment, other drugs, compounds and/or materials used in combination with the particular particle employed, the age, sex, weight, condition, general health and prior medical history of the patient being treated, and like factors well known in the medical arts.

A physician or veterinarian having ordinary skill in the art can readily determine and prescribe the effective amount of the pharmaceutical composition required. For example, the physician or veterinarian could start doses of the structures described herein employed in the pharmaceutical composition at levels lower than that required to achieve the desired therapeutic effect and then gradually increasing the dosage until the desired effect is achieved.

In some embodiments, a polymer, particle or pharmaceutical composition described herein is provided to a subject chronically. Chronic treatments include any form of repeated administration for an extended period of time, such as repeated administrations for one or more months, between a month and a year, one or more years, or longer. In many embodiments, a chronic treatment involves administering a particle or pharmaceutical composition repeatedly over the life of the subject. For example, chronic treatments may involve regular administrations, for example one or more times a week, or one or more times a month.

While it is possible for a a polymer, particle or active agent described herein described herein to be administered alone, it may be administered as a pharmaceutical composition as described above. The present invention also provides any of the above- mentioned compositions useful for diagnosing, preventing, treating, or managing a disease or bodily condition packaged in kits, optionally including instructions for use of the composition. That is, the kit can include a description of use of the composition for participation in a particular disease or bodily condition, The kits can further include a description of use of the compositions as discussed herein. Instructions also may be provided for administering the composition to the pericardial space by any of the suitable techniques described herein.

The kits described herein may also contain one or more containers, which can contain components such as the polymer, particle or active agent herein and/or active agents as described herein. The kits also may contain instructions for mixing, diluting, and/or administrating the particles. The kits also can include other containers with one or more solvents, surfactants, preservatives, and/or diluents (e.g., normal saline (0.9% NaCl), or 5% dextrose) as well as containers for mixing, diluting or administering the polymer, particle or active agent described hereinto the patient in need of such treatment.

The compositions of the kit may be provided as any suitable form, for example, as liquid solutions or as dried powders. When the composition provided is a dry powder, the powder may be reconstituted by the addition of a suitable solvent, which may also be provided. In embodiments where liquid forms of the composition are used, the liquid form may be concentrated or ready to use. The solvent will depend on the particular particle and the mode of use or administration. Suitable solvents for compositions are well known and are available in the literature.

The kit, in one set of embodiments, may comprise one or more containers such as vials, tubes, syringes, and the like, each of the containers comprising one or more of the elements to be used in the method. For example, one of the containers may contain a solution or suspension of polymer, particle or active agent described herein.

Additionally, the kit may include containers for other components, for example, buffers or diluents to be mixed with the polymer, particle or active agent described hereinprior to delivery.

As used herein, a "subject" or a "patient" refers to any mammal (e.g., a human), for example, a mammal that may be susceptible to a disease or bodily condition.

Examples of subjects or patients include a human, a non-human primate, a cow, a horse, a pig, a sheep, a goat, a dog, a cat or a rodent such as a mouse, a rat, a hamster, or a guinea pig. Generally, the invention is directed toward use with humans. A subject may be a subject diagnosed with a certain disease or bodily condition or otherwise known to have a disease or bodily condition. In some embodiments, a subject may be diagnosed as, or known to be, at risk of developing a disease or bodily condition.

These above descriptions of applications for the inventive compositions and methods devices are not intended to be exhaustive, and merely illustrate some of the possible embodiments and uses of this invention.

The function and advantage of these and other embodiments of the present invention may be more fully understood from the examples below. The following examples, while illustrative of certain embodiments of the invention, do not exemplify the full scope of the invention.

EXAMPLES

Example 1

This example demonstrates development of a composition for pericardial injection. To achieve meaningful infarct regression by inducing cardiomyocyte proliferation, the constant presence of a mitogenic stimulus was required. A controlled delivery system was designed to apply an active agent to the cardiac extracellular matrix. It was discovered that certain active agents have the ability to bind non-covalently to Gelfoam^®,, a preparation of collagen, and be gradually released, indicating that Gelfoam^® can provide a suitable delivery vehicle. The solid Gelfoam^®, was homogenized by rasping into small particles to make it injectable (FIG. 2A).

It was determined how fast homogenized Gelfoam^®, would be degraded in pig pericardial fluid and found that Gelfoam^®, particles persisted for 9 days at 38 °C in vitro versus greater than 60 days at 38 °C in saline (FIG. 2B). The Gelfoam^® ,particles in pericardial fluid or saline were slowly agitated in an Eppendorf tube on a shaker, and degradation of the Gelfoam^®, particles was scored daily by visual inspection.

The homogenized Gelfoam^®, once homogenized by rasping into small particles could now be injected through a 5F introducer. A minimally invasive approach was then developed to insert the introducer through the pericardium into the pericardial space (FIG. 2C). The so injected Gelfoam^® material covered the left ventricular free wall containing the myocardial infarct scar and after closure of the puncture site was completely retained within the pericardium (FIG. 2D). Echocardiography was performed immediately after, one week after, and four weeks after injection and did not find pericardial effusions, indicating that the delivery system is biocompatible. Importantly, at one week (FIG. 2E), the Gelfoam^® had formed an elastic membrane overlying the area of the infarction. No Gelfoam^® was visible on the inferior wall. One month after application, the Gelfoam^® delivery system was completely degraded, indicating good biodegradation. The pericardial sheet could be easily peeled off the epicardial surface 3 months after administration, thus demonstrating the absence of major pericardial adhesions. Example 2

This example provides additional description of the materials and methods employed for Example 1 above.

Animal Studies. All procedures were approved by the Institutional Animal Care Committee. Non-surgical procedures were performed under anesthesia with propofol (8- 15 mg/h) and surgery under isoflurane anesthesia (0.8-1.2 % in 100% oxygen). In the experiments, 13 female Yorkshire pigs (weight approximately 20 kg) underwent percutaneous transluminal coil embolization of the left anterior descending coronary artery (LAD). The animals were randomized to receive either control Gelfoam^®

(Surgifoam, Johnson & Johnson, USA) with the buffer used to dissolve active agents for delivery or Gelfoam^® with the active agent. Structural and functional assessment at baseline, 2 days after MI generation, at 1 month and after 3 months was performed.

Experimental myocardial infarction. An 8F sheet was introduced into the femoral artery and cannulated the LAD with an 8F hockey stick guiding catheter (Cordis Infiniti, Johnson & Johnson, USA), 100 micrograms nitroglycerin were injected, and baseline coronary angiography was performed. A platinum embolic coil (0.035 in, 40 mm length, 5x3-mm diameter, Cook Medical Inc, Bloomington, IN) was placed with a 4F AR catheter (Cordis Infiniti, Johnson & Johnson, USA) into the LAD after the takeoff of the first diagonal branch. This completely occluded 2/3 of the LAD tributary, determined by coronary angiography, resulting in infarction of approximately 18% of the left ventricle, determined by TTC staining. The 48 hour rate of survival after infract creation was 75%.

Controlled release system and delivery strategy. Gelfoam^® sheets were homogenized with rasping to prepare an injectable Gelfoam^® slurry. 0.1 mg of dissolved active agent (treatment group) were added per mL of Gelfoam^® or the same volume of buffer (control group). A 4 cm lateral thoracotomy was made to puncture the pericardial sac with a 5F introducer. Approximately 7 mL of pericardial fluid was aspirated, and 7 mL of Gelfoam slurry containing active agent (0.7 mg) or control buffer was injected. The sheet was retracted and the puncture hole was closed with a purse string suture.

Assessment of myocardial function and structure. To determine myocardial repair, myocardial function and structure was assessed at baseline (i.e., before MI generation), 48 hours after myocardial infarction (i.e., before application of the delivery system), 1 month, and 3 months after application of the delivery system.

Echocardiography. Images were acquired with an iE33 ultrasound machine (Philips Medical Systems) equipped with an X3-1 and S8-3 transducer during end- expiratory breath-hold in an R-wave-trigged mode.

Cardiac MRI. Contiguous short-axis cine images covering the LV from base to apex were acquired with a 1.5 T magnet (Magneton Sonata, Siemens Medical Solutions) using a phased-array cardiac coil with ECG gating during end-expiratory breath-hold. Imaging of delayed enhancement (DE) was performed 15 minutes after the

administration of 0.2 mmol/kg gadopentate dimeglumine (Magnevist, Bayer Medical Solutions, Germany) in an inversion-recovery fast gradient-echo sequence. All images were acquired and analyzed by an investigator blinded to the study arm. LV function analysis was performed with Argus software (Argus, "Siemens Medical Solutions). DE was quantified with prototype analysis software (QMass v7, medis, Leiden, Netherlands).

Catheterization. The femoral artery and vein were accessed with 7F sheets. A 6F Millar Micro-Tip catheter system (Millar Instruments Inc.) was placed into the aorta, the left ventricle, and the right ventricle. The following parameters were collected and analyzed: systolic pressure, enddiastolic pressure, peak LV pressure rate of rise

(dP/dt)max and Tau value (time constant of isovolumic relaxation). (dP/dt)max/P was calculated as (dP/dt)max/(systolic - end-diastolic pressure). The mean of at least 3 consecutive cardiac cycles was calculated for each measurement. Coronary angiography and left ventriculography (LVG) were performed at day 2, after one, and three months using a Integris H5000 single-plane fluoroscopy system (Philips Medical Systems) to determine the LV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF).

Assessment of active agent effects at the tissue level. Using a pathology knife (Tissue Tek, Sakura Finetek, USA), the left ventricle was cut into 6 slabs of the same thickness. Viable myocardium was visualized by staining 5 of these slabs with 2,3,5- triphenyltetrazolium chloride and digitally quantified the scar area.

Statistical analyses. Four Investigators quantified observations independently from one another and in a blinded manner. Numeric data are presented as mean ± s.e.m. Statistical significance was tested using SPSS (ver 16) software with one and two-sided ANOVA, where appropriate. Sigmoidal nonlinear or linear regression was used to fit data (GraphPad). The avalue was set at 0.05.

Example 3

This example demonstrates the feasibility of injecting liquified Gelfoam^® particles associated with biological agents into the pericardial space as a potential therapeutic strategy for targeted delivery to the myocardium. Using intravascular ultrasound (IVUS) guidance for additional safety, this method proved to be successful in delivering mesenchymal stem cells (MSCs) and adenovirus to the infarcted heart.

Gelfoam^® particles were created by rasping a block of gelfoam with a commercially available bone rasp. Particles were collected and gas sterilized prior to injection. The particles measured between l-4mm in size. The cotton-like structure of the particles became visible under light microscopy (FIG. 3A). When in contact with water the Gelfoam^® transformed into a thick, slurry paste that was pumped rapidly several times between two connected 10 mL syringes.

To determine whether the Gelfoam^® would dissolve in pericardial fluid in vitro, we harvested fresh samples of pericardial fluid and added Gelfoam^® particles before placing the samples at 38 °C in a shaker in order to simulate the movement of the heart. Control samples were stored at room temperature and in saline solution (FIG. 3B). The Gelfoam^® dissolved completely after about 8.4 days in the samples that were kept in the incubator. After 14 days of observation, the control samples did not noticeably dissolve.

Before starting the in- vivo experiments, the survival of MSCs labeled with enhanced green fluorescent protein (EGFP) in the Gelfoam^® matrix was tested using the methods described above but maintaining the MSC/ Gelfoam^® mix in a cell culture dish in the incubator and changing the culture media biweekly. Under these conditions, cells were visible within the three-dimensional structure of the gelfoam for up to 14 days (FIG. 3C). For large animal in vivo studies, a flouroscopic-guided approach to the pericardial sac was developed (FIG. 3D). As depicted in FIG. 3D, a needle 310 was advanced under the sternum 320 towards the pericardium 330. The procedure allowed precise

positioning of the catheter over the anterior wall of the LV before injection of the gelfoam (FIG. 4A).

The presence of the Gelfoam^® in the pericardium was confirmed by mixing the gelfoam with 50% saline and 50% contrast dye before injection. Fluoroscopic pictures were acquired every 10 minutes for up to 90 minutes to assess the amount of leakage after removal of the catheter (FIG. 4B). Leakage occurred to a large extent when only liquid contrast dye was injected. This effect is presumably enhanced by gravity in combination with the higher density of the liquid dye. In contrast, almost no Gelfoam^® was visible in the chest cavity, even when the puncture site was not closed. In order to improve this approach further, these procedures were performed using a Starclose SE vascular closure device (Abbott, Abbott Park, IL) to seal the pericardium. This strategy resulted in elimination of any visible leakage, even after injection of pure liquid contrast dye.

The distribution of the Gelfoam^® in relation to the infarct zone is depicted in FIG. 4C. To increase safety of the percutaneous puncture, an IVUS-guided approach was further established. The IVUS probe was advanced after the subxiphoid access and positioned next to the pericardial sac at the proposed puncture site (FIG. 4C). The ultrasound probe at the tip of the catheter produces a real-time picture to inspect the size of the space between the heart and the pericardial membrane in diastole and systole (FIG. 5A). The distance between the heart and the pericardial membrane can become altered from post-infarction effusion (upper panel) or adhesion (lower panel). With this instrument, a decrease in pericardial space due to severe pericardial effusion was visualized (FIG. 5B) with removal of two times 20 mL of fluid. Statistical analysis showed significant differences in the setting of severe adhesion and pericardial effusion versus the pericardial space of a naive animal in systole (baseline: 2.1±0.2 mm vs.

adhesion: 0.9±0.08 mm vs. effusion: 3.98±1.1 mm; P < 0.05) (FIG. 5C).

PCR and immunocytochemistry was performed on the myocardial tissue samples in order to assess the efficacy of the delivery method. Fluorescent microscopy images obtained from tissue harvested one week after MSC delivery (n=2) demonstrated the successful engraftment of EGFP labeled MSCs in the peri-infarct area and scar (FIG. 6A). The presence of MSCs in the peri-infarct area was demonstrated by the presence of clusters of cells stained positive for EGFP.

Furthermore, PCR confirmed the presence of MSCs in the myocardium and EGFP expression in the cardiomyocytes after adenoviral injection (FIG. 6B). In the animals that received adenoviral injection, fluorescent microscopy demonstrated the presence of EGFP positive cells in the epicardial layer of the anterior, peri-infarct area, while no expression was found in other layers of the myocardium (FIG. 6C). Example 4

This example provides materials and methods information for Example 3 above. Experimental study. The study was performed in accordance with the

Guidelines for the Care and Use of Laboratory Animals and was approved by the Subcommittee on Research Animal Care at Mount Sinai School of Medicine. Yorkshire swine were anesthetized using Atropine 0.04 mg/kg and Telazol (tiletamine / zolazepam) 6.0 mg/kg. Animals were intubated and ventilated with 100% oxygen. General anesthesia was maintained with Propofol 5mg/kg/hr throughout the interventional procedures. Surgical procedures such as the bone marrow puncture and the thoracotomy were performed under anesthesia with Isoflurane (1-2%) mixed with 98% Oxygen. For myocardial infarction (MI) generation, an 8F sheath was introduced into the femoral artery and cannulated the left anterior descending artery (LAD) with an 8F hockey stick guiding catheter (Cordis Infiniti, Johnson & Johnson, New Brunswick, NJ). After injecting 100 g nitroglycerin and obtaining a baseline coronary angiogram, a platinum embolic coil (0.035 in, 40 mm length, 5><3-mm diameter, Cook Medical Inc.,

Bloomington, IN) using a 4F amplatz right catheter (Cordis Infiniti, Johnson & Johnson) was placed into the LAD after the takeoff of the first diagonal branch, thus occluding 2/3 of the LAD tributary, determined by coronary angiography.

Gelfoam^® particles. A previously reported controlled release system, consisting of solid Gelfoam^® (Pfizer, New York, NY), was adapted for minimally invasive delivery by preparing a Gelfoam^® slurry. As a first step the ability of gelfoam to dissolve in saline and in pericardial fluid, obtained immediately before incubating it with the gelfoam, was tested. The lmL plastic tubes (BD, Franklin Lakes, NJ) were stored either at room temperature or in an incubator (37 °C and 5% C0₂).

Pericardial injection of Gelfoam^® particles. In order to make this approach suitable for preclinical testing, a percutaneous method of accessing the pericardial space and injecting the liquified Gelfoam^® was developed. Injections were performed 48 hours after myocardial infarction. Under fluoroscopic guidance a 18G puncture needle (Cook Medical) was advanced under the sternum towards the pericardium. After confirming successful puncture with a small bolus injection of contrast dye a wire was placed in the pericardial space. After puncture clear pericardial fluid could be aspirated. Only in a few cases the fluid contained small amounts of blood, which had no implications for the safety of the procedure. A 8F vascular sheath was then placed over the wire and thereafter a 5 French Amplatz Right catheter was inserted and positioned over the anterior wall of the LV.

Intravascular ultrasound (IVUS). Measurement of the distance between the pericardial sac and the heart was performed with a Galaxy Intravascular Ultrasound catheter (Boston Scientific, Ample Groove, MN, USA). After subxyphoid puncture, the ultrasound probe was advanced over the 8F sheath towards the pericardial sac. The procedure was performed under fluoroscopic guidance and during breath-hold.

Porcine bone marrow derived mesenchymal stem cell isolation and labeling. Four weeks prior to the scheduled Gelfoam^® /stem cell pericardial injection procedure, bone marrow was harvested from the posterior iliac crest of each pig. All surgical procedures were performed with the animals under general anesthesia and maintained on a ventilator. Autologous bone marrow derived mesenchymal stem celss (MSCs) were isolated and expanded in culture following established protocols. The bone marrow aspirate (12mL) was processed by density gradient centrifugation with Ficoll Paque- PLUS (GE Healthcare Biosciences, Piscataway, NJ); the buffy coat containing the mononuclear cells was collected, and after wash with Hanks Balanced Salt Solution and centrifugation at 500g for 10 minutes, the cell pellet was resuspended in Dulbecco's modified Eagle's medium (DMEM) low glucose (lg/L) (Sigma, St Louis, MO) supplemented with 10% fetal bovine serum (FBS). Cells were plated on tissue culture treated dishes and maintained at 37C and 5% carbon dioxide. The media was changed every 72 hours, cells were trypsinized when they reached 80-90% confluency and re- seeded in T-175 flasks with vented cap. When cells reached passage 3, they were labeled to express green fluorescent protein via infection with adenovirus carrying the reporter gene EGFP; 72 hours after infection, EGFP expression was confirmed under fluorescent microscopy.

Gelfoam^® /MSC constructs. Gelfoam^® sponge was used as a scaffold for seeding MSC by an adaptation of previously described protocols. The Gelfoam^® particles (1-4 mm) were placed in a 50mL polystyrene conical tube with DMEM and hydrated for 2 hours on a VariMix Shaker (Thermo Fisher Scientific, Waltham, MA), at room temperature. The culture media was decanted and the Gelfoam^® was dabbed dry on a gauze, and transferred to a 50mL tube containing a suspension of 6x 107 MSC- eGFP labeled cells in 3mL of DMEM, and incubated for 2 hours at 37 °C and 5% C0₂. The Gelfoam^® /MSC construct was transferred to a 10ml syringe by removing and replacing the plunger, and was immediately used for in vivo implantation. For the preliminary in-vitro testing the construct was transferred onto a cell culture dish and incubated at 37 °C.

Viral vector. Recombinant adenoviral vectors were produced using standard techniques. Briefly, the EGFP gene was subcloned from the pEGFP-Cl vector

(Clontech, Mountain View, CA) to the pShuttle-CMV vector of the AdEasy system. The resulting construct, which carries the EGFP gene under the control of the

Cytomegalovirus promoter, was transformed to the B J5182- AD- 1 (Stratagene, Santa Clara, CA), which are stably transfected with the p AdEasy- 1 plasmid, that carries the adenoviral genes necessary for amplification in the HEK293 genes. These pShuttle- CMV-EGFP-C1 and p AdEasy- 1 undergo homologous recombination to produce a plasmid construct containing the CMV-EGFP-Cl cassette and the adenoviral genes. The resulting construct was transformed to HE 293 cells and the resulting adenoviral virus was used for 4 rounds of amplification. The large-scale adenoviral product was purified using CsCl gradient ultracentrifugation and was quantified by plaque assay. The concentration was determined as 1013 pfu (particle forming units)/mL.

Intrapericardial delivery and cell tracking. To test the feasibility of using the gelfoam intrapericardial injection as a method of delivery of stem cells, gelfoam/MSC constructs were created using MSC- EGFP labeled cells seeded on gelfoam particles and delivered through a percutaneous approach into the pericardial sac, using a 6Fr catheter. This procedure was performed 48 hours after myocardial infarction creation in 2 pigs that underwent bone marrow harvest four weeks prior to the planned MSC implantation procedure. One week after Gelfoam/MSC implantation the animals were sacrificed. To track the presence of MSC in the myocardium, the heart tissue was harvested and processed for immunohistochemistry and molecular analysis for identification of EGFP positive cells.

Immunohistochemistry was performed on frozen tissue sections (ΙΟμπι) using anti-GFP rabbit IgG as primary antibody (Al 1122, Invitrogen) and Texas Red goat anti- rabbit IgG (T2767 Invitrogen) as secondary antibody followed by mounting media containing 4',6-diamidino-2-phenylindole (DAPI). PCR was performed using the following primers: Forward 5 ' -TGACCCTG AAGTTC ATCTGC ACC A-3 ' (SEQ ID NO. 1), Reverse 5 '-TCTTGTAGTTGCCGTCGTCCTTGA-3 ' (SEQ ID NO. 2).

Statistical analyses. Numeric data are presented as mean ± s.e.m. Statistical significance was tested with Student's t test and ANOVA using Prism (Graph Pad, La Jolla, CA) software. The a-value was set at 0.05.

Example 5

This Example provides further description of the figures referred to in Examples 3 and 4.

FIGs. 3A-3D - Sponges of commercially available Gelfoam^® can be rasped into small particles that appear cotton-like under the microscope (FIG. 3 A). In vitro

Gelfoam^® particles can dissolve in pericardial fluid, but not in saline (FIG. 3B).

Mesenchymal stem cells within the 3-D scaffold of Gelfoam^® fibers in the cell culture dish (FIG. 3C). The pericardial sac is approached by substernal puncture, safely bypassing the liver under fluoroscopic guidance (FIG. 3D).

FIGs. 4A-4C - Under fluoroscopic guidance, a wire, followed by a catheter was inserted into the pericardium and positioning was confirmed by contrast dye bolus injection (FIG. 4A). Fluoroscopic images of liquid dye, gelfoam mixed with dye, and liquid dye after closure of the puncture site to assess possible leakage (FIG. 4B).

Position of the injected Gelfoam^® as well as the IVUS probe in relation to the infarct zone (FIG. 4C). FIGs. 5A-5C - With the ultrasound probe at the tip of the catheter, the size of the space between the heart and the pericardial membrane can be assessed precisely in diastole and systole. Lower panels show a smaller range of variation in the size of the pericardial space in a pig with severe pericardial adhesions compared to a control pig in the upper panels (FIG. 5A). Note different scales for upper and lower panels. The real time pictures from the IVUS system show an immediate decrease of the pericardial space by removal of pericardial fluid in the presence of effusion (FIG, 5B). Pericardial space was measured in naive pigs (baseline) and in animals after myocardial infarction showing either pericardial effusion or adhesions (FIG. 5C); the latter were confirmed during thoracotomy (n=4).

FIGs. 6A-6C - Fluorescent microscopy images demonstrate the engraftment of EGFP labeled mesenchymal stem cells in the peri infarct area and scar. (FIG. 6A) Immunostaining performed with anti-GFP rabbit IgG, and secondary antibody goat anti rabbit IgG (Texas red) and nuclei counterstained with DAPI (blue), a) Representative image of control sample, negative for EGFP, demonstrate only counterstained blue nuclei (a representative sample is indicated by the arrows in panel (a)), b-c) The presence of mesenchymal stem cells in the peri infarct area is demonstrated by the presence of clusters of cells stained positive for EGFP using a secondary antibody conjugated to a red fluoropore (arrow) (a representative sample of red and blue staining is indicated in panels (b) and (c)). d) Mesenchymal stem cells (GFP+) identified in scar tissue (arrow) (a representative sample of red and blue staining is indicated in panel (d)). (FIG. 6B) PCR results. (FIG. 6C) Fluorescent microscopy of eGFP transfection (a representative sample of red and blue staining is indicated). While several embodiments of the invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and structures for performing the functions and/or obtaining the results or advantages described herein, and each of such variations, modifications and improvements is deemed to be within the scope of the present invention. More generally, those skilled in the art would readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that actual parameters, dimensions, materials, and configurations will depend upon specific applications for which the teachings of the present invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described. The present invention is directed to each individual feature, system, material and/or method described herein. In addition, any combination of two or more such features, systems, materials and/or methods, provided that such features, systems, materials and/or methods are not mutually inconsistent, is included within the scope of the present invention.

In the claims (as well as in the specification above), all transitional phrases or phrases of inclusion, such as "comprising," "including," "carrying," "having,"

"containing," "composed of," "made of," "formed of," "involving" and the like shall be interpreted to be open-ended, i.e., to mean "including but not limited to" and, therefore, encompassing the items listed thereafter and equivalents thereof as well as additional items. Only the transitional phrases or phrases of inclusion "consisting of and

"consisting essentially of are to be interpreted as closed or semi-closed phrases, respectively. The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

All references cited herein, including patents and published applications, are incorporated herein by reference. In cases where the present specification and a document incorporated by reference and/or referred to herein include conflicting disclosure, and/or inconsistent use of terminology, and/or the incorporated/referenced documents use or define terms differently than they are used or defined in the present specification, the present specification shall control.

What is claimed is:

Claims

1. A method for treating the heart of a human or animal subject, comprising:

injecting a polymer into the pericardial space of the subject, wherein the polymer prevents adhesion from forming between a first tissue and a second tissue in the pericardial space.

2. The method of claim 1 , wherein the polymer is configured to act as a sustained release vehicle for an active agent.

3. The method of claim 1 , wherein the polymer further comprises an active agent.

4. The method of claim 1, wherein the polymer is biodegradable.

5. The method of claim 1, wherein the polymer forms a hydrogel.

6. The method of claim 1 , wherein the polymer comprises collagen.

7. The method of claim 1 , wherein the polymer comprises gelatin.

8. The method of claim 1 , wherein the polymer becomes substantially immobilized in the pericardial space after injection.

9. The method of claim 1 , wherein the first tissue and the second tissue are substantially the same type of tissue.

10. The method of claim 1, wherein the first tissue and the second tissue are different types of tissue.

11. The method of claim 3, wherein the active agent comprises a virus or cell.

12. The method of claim 11, wherein the cell is a stem cell.

13. The method of claim 1 1 , wherein the virus is an adenovirus.

14. The method of claim 3, wherein the active agent comprises a transfection vector.

15. The method of claim 3, wherein the active agent comprises a pharmaceutical composition.

16. The method of claim 1, wherein the polymer is injected in particulate form.

17. A method for treating the heart of a human or animal subject, comprising:

injecting a plurality of particles comprising gelatin into the pericardial space of the subject, wherein the particles further comprise an active agent and are configured to act as a sustained release vehicle for the active agent.

18. The method of claim 17, wherein the particles are capable of preventing adhesion from forming between a first tissue and a second tissue in the pericardial space.

19. The method of claim 18, wherein the first tissue and the second tissue are substantially the same type of tissue.

20. The method of claim 18, wherein the first tissue and the second tissue are different types of tissue.

21. The method of claim 17, wherein the particles become substantially immobilized in the pericardial space after injection.

22. The method of claim 17, wherein the active agent is a vector.

23. The method of claim 17, wherein the active agent comprises a virus or cell.

24. The method of claim 23, wherein the cell is a stem cell.

25. The method of claim 23, wherein the virus is an adenovirus.

26. The method of claim 17, wherein the active agent is pharmaceutical composition.

27. The method of claim 17, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, greater than 500 microns.

28. The method of claim 27, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, greater than 1 millimeter.

29. The method of claim 27, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, between 500 microns and 2 millimeters.

30. The method of claim 29, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, between 500 microns and 1 millimeter.

31. The method of claim 29, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, between 1 millimeter and 2 millimeters.

32. A method for treating the heart of a human or animal subject, comprising:

injecting a plurality of particles having an average particle size, corresponding to the 50% point in the weight distribution of particles, greater than 500 microns into the pericardial space of the subject, wherein the particles further comprise an active agent and are configured to act as a sustained release vehicle for the active agent.

33. The method of claim 32, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, greater than 1 millimeter.

34. The method of claim 33, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, between 500 microns and 2 millimeters.

35. The method of claim 34, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, between 500 microns and 1 millimeter.

36. The method of claim 34, wherein the particles have an average particle size, corresponding to the 50% point in the weight distribution of particles, between 1 millimeter and 2 millimeters.

37. The method of claim 32, wherein the particles are capable of preventing adhesions from forming between a first tissue and a second tissue in the pericardial space.

38. The method of claim 37, wherein the first tissue and the second tissue are substantially the same type of tissue.

39. The method of claim 37, wherein the first tissue and the second tissue are different types of tissue.

40. The method of claim 32, wherein the particles become substantially immobilized in the pericardial space after injection.

41. The method of claim 32, wherein the active agent is a vector.

42. The method of claim 32, wherein the active agent comprises a virus or cell.

43. The method of claim 42, wherein the cell is a stem cell.

44. The method of claim 42, wherein the virus is an adenovirus.

45. The method of claim 32, wherein the active agent is pharmaceutical composition.

46. The method of claim 32, wherein the particles comprise gelatin.

47. A method for treating the heart of a human or animal subject, comprising:

injecting a polymer comprising a virus or cell into the pericardial space of a subject.

48. The method of claim 47, wherein the polymer is capable of preventing adhesion from forming between a first tissue and a second tissue in the pericardial space.

49. The method of claim 48, wherein the first tissue and the second tissue are substantially the same type of tissue.

50. The method of claim 48, wherein the first tissue and the second tissue are different types of tissue.

51. The method of claim 47, wherein the polymer is configured to act as a sustained release vehicle for the virus or cell.

52. The method of claim 51 , wherein the polymer is configured to act as a sustained release vehicle for a pharmaceutical composition.

53. The method of claim 47, wherein the polymer comprises gelatin.

54. The method of claim 47, wherein the polymer is biodegradable.

55. The method of claim 47, wherein the polymer becomes substantially immobilized in the pericardial space after injection .

56. The method of claim 47, wherein the polymer is injected in particulate form.

57. The method of claim 47, wherein the cell is a stem cell.

58. The method of claim 47, wherein the virus is an adenovirus.

59. The method of claim 47, wherein the human or animal subject shows evidence of engraftment at least 2 weeks after injection.

60. The method of claim 47, wherein the human or animal subject shows evidence of transfection of cardiac tissue at least 2 weeks after injection.

61. The method of claim 47, wherein the cell is grown on the polymer prior to injection into the pericardial space.