Biological breast implant

Abstract

To provide a tissue product, more specifically, an extracellular tissue matrix made from adipose tissue.SOLUTION: A tissue product is provided, wherein the tissue product comprises a breast implant in the form of a porous acellular tissue matrix sponge, wherein the implant comprises an acellular adipose tissue matrix construct comprising a particulate acellular adipose tissue matrix, wherein the matrix is in a suspended, dried and stabilized form, and wherein the suspension comprises 2-10 wt.% solids.SELECTED DRAWING: None

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to tissue products, and more particularly to extracellular tissue matrices made from adipose tissue.

[0002] This disclosure claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 62 / 854,678, filed May 30, 2019, the entire contents of which are incorporated herein by reference.

[0003] Various tissue-derived products have been used to regenerate, repair, or otherwise treat diseased or damaged tissues and organs. Such products can include tissue grafts and / or processed tissues (e.g., acellular tissue matrices from skin, intestine, or other tissues, with or without cell seeding). Such products generally have properties determined by the tissue source (i.e., the type of tissue and the animal from which it originates) and the processing parameters used to produce the tissue product. Because tissue products are often used for surgical applications and / or tissue replacement or augmentation, the product must support tissue growth and regeneration as desired at the selected implantation site. The present disclosure provides adipose tissue products that can improve tissue growth and regeneration for various applications, such as breast implants.

[0004] According to certain embodiments, a method for producing a tissue product is provided that includes the steps of selecting adipose tissue, mechanically treating the adipose tissue to reduce the size of the tissue, treating the mechanically treated tissue to remove substantially all cellular material from the tissue, suspending the tissue in a liquid to form a suspension, and drying the suspension in a mold to form a porous sponge.

[0005] In various embodiments, the adipose tissue is processed to control specific mechanical properties. For example, the processed tissue may be crosslinked to provide a stable three-dimensional structure. Additionally or alternatively, the solids content of the sponge or suspension can be controlled, as described in more detail below.

[0006] Also provided herein are tissue products made by the disclosed processes.

[0007] In some embodiments, the tissue product comprises a decellularized adipose extracellular tissue matrix, the tissue matrix formed into a predetermined three-dimensional shape, and the tissue matrix partially crosslinked to maintain the three-dimensional shape.

[0008] Also provided herein are tissue products comprising breast implants, which can include an adipose tissue matrix formed with a desired set of mechanical properties controlled by the percentage of crosslinking and / or solids.

[0009] Further provided herein is a method of treatment comprising selecting a tissue site and implanting a tissue product disclosed herein into the tissue site. The method may include implanting the treatment device at or near a wound or surgical site and securing at least a portion of the treatment device to tissue at or near the treatment site. The tissue product is implanted posterior to the tissue site to reinforce, reposition, or outwardly protrude native tissue. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a flow chart outlining a process for manufacturing an adipose tissue matrix sponge, according to certain embodiments. [Figure 2] FIG. 2 is a side view of a layered biological breast implant according to certain embodiments. [Figure 3]Figures 3A, 3B, and 3C are perspective views of a breast implant configuration having a layered structure according to certain embodiments, another configuration of a breast implant having a layered structure according to certain embodiments, and another configuration of a breast implant having a layered structure according to certain embodiments. [Figure 4] FIG. 4 illustrates the implantation of a system for surgical breast procedures that includes a preformed tissue matrix, according to certain embodiments. [Figure 5] 5A-5G are histological images showing the effect of EDC crosslinking on adipogenesis. [Figure 6] Figure 6A is a bar graph showing the effect of fat matrix solids on compressive strength, Figure 6B is a bar graph showing the effect of fat matrix solids on recovery, Figure 6C is a bar graph showing the effect of fat matrix solids on elasticity, and Figure 6D is a bar graph showing the effect of fat matrix solids on elastic modulus. DETAILED DESCRIPTION OF THE INVENTION

[0011] Reference will now be made in detail to certain exemplary embodiments consistent with the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0012] In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of "or" means "and / or" unless specifically stated otherwise. Furthermore, the use of the term "comprising" and other forms such as "includes" and "including" is not limiting. Any range described herein should be understood to include the endpoints and all values ​​between those endpoints.

[0013] The section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described. All documents or portions of documents cited in this application, including but not limited to patents, patent applications, articles, books, and papers, are expressly incorporated herein by reference in their entirety for any purpose.

[0014] As used herein, "tissue product" refers to any human or animal tissue that contains extracellular matrix proteins. "Tissue product" includes acellular or partially decellularized tissue matrix, as well as decellularized tissue matrix that has been repopulated with exogenous cells.

[0015] As used herein, the term "acellular tissue matrix" refers to an extracellular matrix derived from human or animal tissue that retains a significant amount of native collagen, other proteins, proteoglycans, and glycoproteins necessary to serve as a scaffold to support tissue regeneration. "Acellular tissue matrix" differs from purified collagen materials, such as acid-extracted purified collagen, which are substantially free of other matrix proteins and do not retain the natural microstructural characteristics of tissue matrices due to the purification process. While referred to as "acellular tissue matrix," it is understood that such tissue matrices are combined with exogenous cells, including, for example, stem cells or cells from the patient into whom the "acellular tissue matrix" is to be implanted. "Decellularized adipose tissue matrix" refers to adipose tissue from which all cells have been removed to produce an adipose extracellular matrix. "Decellularized adipose tissue matrix" can include intact matrix or matrix that has been further processed as discussed herein, including mechanical processing, sponge formation, and / or further processing to produce a particulate matrix.

[0016] It will be understood that "acellular" or "decellularized" tissue matrix refers to a tissue matrix in which no cells are visible using a light microscope.

[0017] Various human and animal tissues can be used to manufacture products for treating patients. For example, various tissue products have been manufactured for the regeneration, repair, augmentation, reinforcement, and / or treatment of human tissue damaged or lost due to various diseases and / or structural damage (e.g., trauma, surgery, atrophy, and / or long-term wear and degeneration). Such products can include, for example, acellular tissue matrices, tissue allografts or xenografts, and / or reconstructed tissues (i.e., at least partially decellularized tissues seeded with cells to provide a material upon which growth can occur).

[0018] Various tissue products have been manufactured to treat soft and hard tissues. For example, ALLODERM® and STRATTICE® (LIFECELL CORPORATION, Branchburg, New Jersey) are two dermal acellular tissue matrices manufactured from human and porcine dermis, respectively. While such materials are highly useful for treating certain types of diseases, materials with different biological and mechanical properties may be desirable for certain applications. For example, ALLODERM® and STRATTICE® have been used to aid in the treatment of structural defects and / or to provide tissue support (e.g., for the abdominal wall or in breast reconstruction), and their strength and biological properties make them suitable for such applications. However, such materials may not be ideal for regenerating, repairing, replacing, and / or augmenting fat-containing tissue, where the desired outcome is the production of adipose tissue containing viable adipocytes. Accordingly, the present disclosure provides tissue products useful for treating tissue defects / defects involving fat-containing tissue. The present disclosure also provides methods for manufacturing such tissue products.

[0019] Tissue products can include adipose tissue that has been processed to remove at least a portion of its cellular components. In some cases, all or substantially all cellular material is removed, thereby leaving behind adipose extracellular matrix proteins. The product can further be processed to remove some or all of the extracellular and / or intracellular lipids. However, in some cases, complete removal of the extracellular and / or intracellular lipids can damage the structure and function of the adipose matrix. For example, adipose tissue that has been chemically or enzymatically processed for extended periods of time can denature or otherwise damage collagen or be depleted of proteins necessary for adipose regeneration. Therefore, in some cases, the product contains a level of residual lipid. The residual lipid content can be, for example, about 5%, 6%, 7%, 8%, 9%, or 10% by weight of the product. As further described below, the extracellular matrix proteins can be further processed to produce three-dimensional porous or spongy materials, and the porous or spongy materials can be further processed to produce injectable products.

[0020] As described above, the tissue products of the present disclosure are formed from adipose tissue. The adipose tissue can be derived from human or animal sources. For example, human adipose tissue can be obtained from cadavers. Additionally, human adipose tissue can be obtained from living donors (e.g., autologous tissue). Adipose tissue can also be obtained from animals, such as pigs or monkeys, or other sources. When using animal sources, the tissue can be further processed to remove antigenic components, such as 1,3-α-galactose moieties, which are present in pigs and other mammals but not in humans or primates. See Xu, Hui, et al., "A Porcine-Derived Acellular Dermal Scaffold that Supports Soft Tissue Regeneration: Removal of Terminal Galactose-α-(1,3)-Galactose and Retention of Matrix Structure," Tissue Engineering, Vol. 15, pp. 1-13 (2009), which is incorporated by reference in its entirety. Additionally, the adipose tissue can be obtained from animals that have been genetically modified to remove antigenic moieties.

[0021] Figure 1 illustrates an exemplary process for manufacturing tissue products of the present disclosure. Figure 1 provides a flow chart illustrating the basic steps to produce a suitable adipose tissue sponge, which can then be further processed to produce injectable or implantable particles. As illustrated, the process may include several steps, but it should be understood that additional or alternative steps may be added or substituted depending on the particular tissue used, the desired application, or other factors.

[0022] As shown, process 100 generally may begin at step 110 with receiving tissue. The tissue may include various adipose tissue types, including, for example, human or animal adipose tissue. Suitable tissue sources include allograft tissue, autograft tissue, or xenograft tissue. When xenografts are used, the tissue may include fat from animals, including porcine, bovine, canine, feline, domestic or wild sources, and / or any other suitable mammalian or non-mammalian fat source.

[0023] Tissues may be harvested from animal sources using any desired technique, but will typically be harvested using aseptic or sterile techniques where possible. Tissues may be stored under cryogenic or frozen conditions, or may be processed immediately to prevent undesirable changes due to long-term storage.

[0024] After receiving the tissue, it is first subjected to a mechanical size reduction process at step 120 and / or a mechanical defatting process at step 130. Mechanical size reduction involves visible or large cuts of the tissue using a manual blade or any other suitable comminution process.

[0025] Mechanical defatting, step 130, is important in tissue preparation. Specifically, fat is subjected to various mechanical processing conditions to aid in lipid removal. For example, mechanical processing can include grinding, blending, shredding, grating, or other processing of the tissue. Mechanical processing can also be performed under conditions that allow for some heating, which can aid in lipid release or removal. For example, mechanical processing can be performed under conditions that heat the adipose tissue up to 122°F (50°C), at temperatures ranging from 42-45°C for porcine fat and slightly lower temperatures for human fat. Application of external heat may be insufficient to release lipids, and thus, heat generated during mechanical disruption may be preferred to aid lipid removal. In some instances, heating during mechanical processing can be a short-duration pulse of elevated temperature. This heat pulse can cause liquefaction of lipids released from adipocytes disrupted by mechanical disruption, subsequently resulting in efficient phase separation for bulk lipid removal. In one example, when processing porcine adipose tissue, the temperature reached during the process exceeds 100°F, but does not exceed 122°F (50°C). The temperature range reached can be adjusted depending on the origin of the adipose tissue. For example, the temperature can be further reduced to about 80°F, 90°F, 100°F, 110°F, or 120°F when processing less saturated tissue, such as primate tissue. Alternatively, the process can be selected so that the fat reaches a minimum temperature of, for example, 80°F, 90°F, 100°F, 110°F, or 120°F.

[0026] In some cases, mechanical delipidation can be performed by mechanically processing the tissue with little or no washing solution. For example, the tissue may be mechanically processed by grinding or mixing without the use of a solvent. Alternatively, if water is required for tissue disruption, e.g., to increase fluidity or reduce viscosity, water can be used, including pure water, saline, or other buffers, including saline or phosphate-buffered saline. In some instances, the tissue is processed by adding a specific amount of a biocompatible solvent, such as saline (e.g., saline, phosphate-buffered saline, or a solution containing salts and / or surfactants). Other solutions that promote cell lysis, including salts and / or surfactants, may also be appropriate.

[0027] In step 140, after mechanical treatment and lipid removal, the fat can be washed. For example, the tissue can be washed with one or more rinses with various biocompatible buffers. For example, suitable wash solutions include saline, phosphate-buffered saline, or other suitable biocompatible materials or physiological solutions. In one example, water can be used as a rinse to further disrupt the cells, followed by the introduction of phosphate-buffered saline or other suitable saline to return the matrix proteins to the biocompatible buffer.

[0028] Washing can be performed in conjunction with centrifugation or other processes to separate lipids from the tissue. For example, in some embodiments, the material is diluted with water or another solvent. The diluted material is then centrifuged, and the free lipids flow to the top, while the extracellular matrix proteins are deposited as a pellet. The protein pellet is then resuspended, and washing and centrifugation are repeated until a sufficient amount of lipids is removed.

[0029] After washing, the adipose tissue can be treated to remove some or all of the cells from the adipose tissue, as shown in step 150. The cell removal process can include multiple suitable processes. For example, suitable methods for removing cells from adipose tissue include treatment with a detergent, such as deoxycholic acid, polyethylene glycol, or other detergent, at a concentration and for a time sufficient to disrupt the cells and / or remove cellular components.

[0030] After cell removal, as shown in step 160, additional processing and / or washing steps can be incorporated depending on the tissue used or the desired final structure. For example, additional washing or processing can be performed to remove antigenic materials, such as alpha-1,3-galactose moieties, that may be present in non-primate tissue. Additionally, additional solutions or reagents can be used to treat the material during, before, and / or after the washing steps. For example, enzymes, detergents, and / or other agents can be used in one or more steps to further remove cellular material or lipids, remove antigenic materials, and / or reduce the bacterial or other bioburden of the material. For example, one or more washing steps can be included that use detergents such as sodium dodecyl sulfate or Triton to aid in the removal of cells and lipids. Additionally, enzymes, such as lipases, DNAses, RNAses, alpha-galactosidase, or other enzymes, can be used to ensure the destruction of nuclear material, antigens from foreign sources, residual cellular components, and / or viruses. Additionally, acidic solutions and / or peroxides may be used to further remove cellular material and help destroy bacteria and / or viruses, or other potential infectious agents.

[0031] After removing lipid and cellular components, the material can be formed into a porous or sponge-like material. As shown in step 170, the extracellular matrix is ​​typically first resuspended in an aqueous solvent to form a slurry-like material. By using a sufficient amount of solvent, the material can be formed into a liquid substance that can be poured into a mold having the size and shape of the desired tissue product. The amount of water or solvent added can vary based on the desired porosity of the final material. In some cases, the slurry-like material can have a solids concentration of about 2% to about 10% by weight, preferably about 2% to about 5% by weight. In some cases, the resuspended extracellular matrix can be further mechanically processed one or more times by grinding, cutting, mixing, or other processes, and the processed material can be centrifuged and resuspended one or more times to further remove cellular material or lipids (if necessary) and / or control the viscosity of the extracellular matrix.

[0032] Once the additional washing and grinding steps are complete, the resuspended material is placed in a container or mold to form a porous, sponge-like product, as shown in step 180. Typically, the porous or sponge-like material is formed by drying the material to leave a three-dimensional matrix of porous structures. In some embodiments, the material is freeze-dried. Freeze-drying allows for the production of a three-dimensional structure that generally conforms to the shape of the mold, as shown in FIG. 3. Specific freeze-drying protocols can be modified based on the solvent used, sample size, and / or to optimize processing time. One suitable freeze-drying process includes cooling the material for a period of time; holding the sample at a certain temperature for a period of time and further cooling the sample to completely freeze it; applying a vacuum; increasing the temperature and holding that temperature for a period of time; and again increasing the temperature and holding that temperature for a period of time. The freeze-dried sample can then be removed from the freeze-dryer and packaged in a foil pouch under nitrogen.

[0033] After the solid or sponge is formed, the material can optionally be stabilized, as shown in step 190. In some cases, stabilization can include additional processes such as crosslinking, treatment with a dehydrothermal (DHT) process, or other suitable stabilization methods. For example, mechanically processed tissues, when formed into a porous matrix, typically form a more putty- or paste-like material when implanted in the body, wetted, or placed in solution. This can result in a loss of the desired shape and size. Furthermore, the porous structure, which is important for supporting cell attachment, tissue growth, vascularization, and tissue regeneration, can be lost. Therefore, the material may be further processed to stabilize its size, shape, and structure.

[0034] In some embodiments, the material is cross-linked for stabilization. In some embodiments, the material is cross-linked after lyophilization. However, the material can also be cross-linked before or during the lyophilization process. Cross-linking can be performed in a variety of ways. In one embodiment, cross-linking can be achieved by contacting the material with a cross-linking agent such as glutaraldehyde, genepin, carbodiimides (e.g., 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC)), and diisocyanates.

[0035] Additionally, crosslinking may be achieved by heating the material under vacuum. For example, in some embodiments, the material may be heated under reduced pressure or vacuum to 70°C to 120°C, or 80°C to 110°C, or up to about 100°C, or any value within a specified range. Additionally, other crosslinking processes, or combinations of processes, including ultraviolet radiation, gamma radiation, and / or electron beam (e-beam) radiation, may be used to produce any of the disclosed products. Furthermore, a vacuum is not required, but may shorten the crosslinking time. Furthermore, lower or higher temperatures may be used as long as melting of the matrix protein does not occur and / or sufficient time is provided for crosslinking.

[0036] In various embodiments, the crosslinking process can be controlled to produce tissue products with desired mechanical, biological, and / or structural characteristics. For example, crosslinking can affect the overall strength of the material, and the process is controlled to produce the desired strength. Furthermore, the amount of crosslinking can affect the ability of the product to maintain a desired shape and structure (e.g., porosity) upon implantation. Thus, the amount of crosslinking can be selected to produce a stable three-dimensional shape when implanted in the body, when in contact with an aqueous environment, and / or when compressed (e.g., by surrounding tissues or materials).

[0037] Excessive crosslinking can alter the extracellular matrix material. For example, excessive crosslinking can damage collagen or other extracellular matrix proteins. Damaged proteins may not support tissue regeneration when the tissue product is placed in an adipose tissue site or other anatomical location. Furthermore, excessive crosslinking can cause the material to become brittle or weak. Therefore, the amount of crosslinking is controlled to provide the desired level of stability while maintaining the desired biological, mechanical, and / or structural characteristics.

[0038] An exemplary crosslinking process can include contacting the freeze-dried material produced as described above with glutaraldehyde or EDC. For example, a 0.1% glutaraldehyde solution can be used, and the tissue is immersed in the solution for approximately 18 hours, followed by extensive rinsing with water and removal of the solution. Alternatively, or in combination, a dehydrothermal (DHT) process can be used. For example, one exemplary dehydrothermal process involves treating the material at 100°C and approximately 20 inches of mercury for 18 hours, followed by immersion in water. The final crosslinked tissue product can be stored in a film pouch.

[0039] Devices manufactured using the above-described methods can have a variety of configurations. For example, FIG. 2 is a side view of a biological breast implant 30 formed with an adipose tissue matrix. The implant can include a variety of suitable breast implant shapes, contours, or projections. Furthermore, it should be understood that a variety of shapes can be used, including rounded, irregular, concentric oval, or concentric irregular 3D shapes, or custom-molded implants. For example, FIGS. 3A-3C show exemplary shapes of implants manufactured using the disclosed methods, including a teardrop-shaped implant 36 (FIG. 3A), an irregular implant 37 (FIG. 3B), and / or a spherical implant 38 (FIG. 3C), each formed with layers 39.

[0040] The devices 30, 36-38 can have a variety of sizes. However, as noted above, the methods provided herein can provide advantages by enabling the production of fat implants having large sizes that can match those of conventional breast implants or tissue expanders. For example, the layering methods described herein can be used to produce implants having at least one dimension of 5 cm or greater. In other cases, the devices have dimensions of at least 6 cm, at least 7 cm, at least 8 cm, at least 10 cm, or greater.

[0041] Also disclosed herein is a method of treating a breast by implanting a tissue product. FIG. 4 illustrates implantation of a system for surgical breast surgery, including a preformed tissue matrix 32 implanted using a breast implant or tissue expander, according to certain embodiments. The method can include first identifying an anatomical site within a breast 60. (As used herein, "intramammary" is understood to mean within the mammary glandular tissue, or within or adjacent to tissue surrounding the breast, such as immediately below, to the sides, or inside the breast, or beneath surrounding tissue, e.g., beneath the chest muscles (pectoralis major), and also includes implantation into a site where part or all of the breast has already been surgically removed.) The site can include, for example, any suitable site requiring reconstruction, repair, augmentation, or treatment. Such sites include sites where surgical oncology surgery (mastectomy, lumpectomy), cosmetic surgery (breast augmentation or revision breast augmentation), or sites requiring treatment due to disease or trauma.

[0042] Further provided herein is a method of treatment comprising selecting a tissue site and implanting a tissue product disclosed herein into the tissue site. The method may include implanting the treatment device at or near a wound or surgical site and securing at least a portion of the treatment device to tissue at or near the treatment site. The tissue product may be implanted posterior to the tissue site, i.e., deep within the tissue site, thereby reinforcing, repositioning, or outwardly projecting native tissue.

[0043] Also provided herein is a method of treatment that includes selecting a tissue site within the breast, implanting a device within the tissue site, and growing tissue within an acellular adipose tissue matrix. In one embodiment, the device comprises a synthetic breast implant or tissue expander and an acellular adipose tissue matrix surrounding the breast implant or tissue expander. The method can further include removing the breast implant or tissue expander and implanting additional acellular adipose tissue matrix into the void created by removal of the breast implant or tissue expander.

[0044] The tissue products described herein can be used to treat a variety of different anatomical sites. For example, as described herein, tissue products of the present disclosure can be generated from an adipose tissue matrix and used to treat breasts. In some cases, the tissue products can be implanted in other sites, including, for example, tissue sites that are primarily or significantly composed of adipose tissue. In some cases, the tissue site can include the breast (e.g., for breast augmentation, replacement of excised tissue, or peri-implant placement). Additionally, any site containing other adipose tissue can be selected. For example, tissue products can be used for reconstructive or cosmetic applications in the breast, face, buttocks, abdomen, hips, thighs, or any other site where additional adipose tissue with a structure and feel similar to natural fat is desired. In any of these sites, the tissue can be used to reduce or eliminate wrinkles, sagging, or undesirable contours.

[0045] Example: Effect of cross-linking on adipogenesis 3D acellular adipose matrix (AAM) sponges can reduce seroma, hematoma, and scar formation while promoting adipogenesis. The mechanical properties of the sponge must be able to adequately withstand compressive forces in the body. To improve the mechanical strength and elasticity of 3D AAM sponges, the sponges were modified by chemical crosslinking (e.g., 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; EDC). However, there is often a trade-off between the biological response and the mechanical strength achieved by crosslinking. Therefore, we evaluated the biological response to crosslinked sponges using a subcutaneous nude rat model.

[0046] AAM slurries were prepared, freeze-dried, and crosslinked with DHT at 80°C for 24 hours. Sponges were crosslinked with 0.016% or 0.125% EDC. N-hydroxysuccinimide (NHS) was also added at a ratio of 5:3. Uncrosslinked sponges were then terminally sterilized by electron beam irradiation at 10 kGy for uncrosslinked sponges and 15 kGy for crosslinked sponges. Sponges approximately 5 mm thick were cut with an 8 mm biopsy punch, washed with saline for 20–30 minutes, and then implanted subcutaneously into nude rats (n=4). After 4 weeks, the explants were cut in half; one half was fixed in 10% formalin for Masson's trichrome staining, and the other half was fixed in sucrose for Oil Red O staining.

[0047] By 4 weeks, uncrosslinked sponges showed cell ingrowth, angiogenesis, and adipogenesis (Figures 5A and 5B). In contrast, sponges crosslinked with 0.125% EDC showed no adipocytes by Oil Red O staining (Figures 5E and 5F). Sponges with an intermediate crosslinking amount (0.016%) showed intermediate levels of adipocytes, comparable to those seen in 0.125% and uncrosslinked sponges (Figures 5C and 5D). However, trichrome staining revealed extensive cell ingrowth and angiogenesis for all sponge types (Figures 5A, 5C, 5E, and 5G). This suggests that adipogenesis is merely delayed, not completely prevented, by EDC crosslinking.

[0048] Overall, increasing EDC cross-linking was accompanied by a concomitant decrease in adipogenesis, as evidenced by trichrome and oil red O staining. All three sponges promoted cell ingrowth and angiogenesis, regardless of cross-linking conditions.

[0049] Example: Effect of treatment on mechanical properties AAM must possess mechanical properties that adequately withstand compressive forces in the body. To improve the mechanical strength and elasticity of 3D AAM sponges, we modified the sponges by (1) changing the solid content of the AAM, (2) chemical crosslinking (e.g., 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; EDC), and (3) adding tropoelastin. Introducing tropoelastin, a precursor of the extracellular matrix protein elastin, can alter the mechanical properties (e.g., elasticity and resilience) of AAM.

[0050] AAM slurries were prepared at 3% or 4% solids in 20% PBS. The slurries were then freeze-dried to form sponges, followed by DHT crosslinking at 80°C for 24 hours. For sponges prepared with 3% or 4% solids slurries and crosslinked with EDC, the sponges were incubated at room temperature for 4 hours in either 0.03% or 0.1% EDC in MES buffer. Additionally, N-hydroxysuccinimide (NHS) was added to the buffer at a ratio of EDC:NHS = 5:3. After crosslinking, the sponges were washed twice with PBS. The solid contents and EDC amounts of the samples were as follows: TIFF2026012665000001.tif46170

[0051] In another sponge composition not shown here, 10 mg / ml tropoelastin in PBS was crosslinked with 10 mM bis(sulfosuccinimidyl) suberate (BS3) for 18 hours at 37°C. The tropoelastin hydrogel was then cut into pieces and incorporated into an AAM slurry at a final concentration of 1%. The tropoelastin and AAM slurry was then lyophilized to form a sponge and crosslinked as described above.

[0052] Compression tests were performed on sponges hydrated with PBS to evaluate their compressive strength at 50% strain, shape recovery after compression, and elastic modulus, where elastic modulus is defined as the slope of the linear region of the force-displacement curve. To evaluate elasticity, tensile tests were performed on sponge strips hydrated with PBS and gently squeezed to remove excess liquid.

[0053] As the percentage of EDC increased, an overall linear trend was observed in compressive strength, elasticity, and modulus (Figures 6A, 6C, and 6D). For each EDC crosslinking condition, the 4% AAM sponge was stronger than its 3% counterpart. The 4% AAM sponge with 0.1% EDC (Sample 6) exhibited the highest strength in these parameters. Figure 6B shows that both the 0.03% and 0.1% EDC crosslinking conditions similarly improved shape recovery by an average of 7.2% compared to the non-crosslinked version.

[0054] Increasing the solids content from 3% to 4% improved the mechanical strength of the sponge. Cross-linking with EDC further improved the mechanical strength of the sponge, resulting in stronger sponges than those obtained with either a higher EDC concentration (0.1%) or a lower EDC concentration (0.03%).

Claims

1. 1. A method of producing a tissue product, comprising: selecting adipose tissue; processing the tissue to remove substantially all cellular material from the tissue; suspending the tissue in a liquid to form a suspension with a solids content of 2-4% by weight; and freezing and drying the suspension to form a porous sponge.

2. 10. The method of claim 1, The method further comprising the step of cross-linking the porous sponge.

3. 3. The method of claim 2, A method characterized in that the crosslinking is carried out using a dehydrothermal process.

4. 4. The method of claim 3, The method further comprising the step of performing a chemical cross-linking process.

5. 10. The method of claim 1, 10. A method of claim 1, wherein the porous sponge has a desired thickness at least at the thickest portion of the sponge, said desired thickness being greater than 10.0 cm.

6. 10. The method of claim 1, The method further comprising the step of adding the suspension to a mold.

7. 7. The method of claim 6, The method, wherein the mold is in the shape of a rounded or teardrop-shaped breast implant.

8. 5. The method of claim 4, The method, wherein the chemical cross-linking step includes at least one of glutaraldehyde, genepin, carbodiimide, and diisocyanate.

9. 5. The method of claim 4, The method wherein crosslinking comprises heating the porous sponge.

10. 10. The method of claim 9, A method characterized in that the porous sponge is heated in a vacuum.

11. 11. The method of claim 10, A method characterized in that the porous sponge is heated to a temperature in the range of 70°C to 120°C.

12. 5. The method of claim 4, A method wherein the porous sponge is crosslinked such that the material maintains a stable three-dimensional structure when in contact with an aqueous environment.

13. 13. The method of claim 12, The method, wherein the aqueous environment is a mammalian body.

14. A tissue product comprising: A tissue product comprising a breast implant, the implant comprising a construct of acellular adipose tissue matrix comprising particulate acellular adipose tissue matrix that has been homogenized, dried, and stabilized to form a suspension, the implant being characterized in that at least one dimension is at least 5 cm.

15. 15. The tissue product of claim 14, The implant is a tissue product characterized in that it has at least one dimension of at least 8 cm.

16. 15. The tissue product of claim 14, A tissue product characterized in that the implant is in the form of a rounded breast implant.

17. 15. The tissue product of claim 14, A tissue product wherein the implant is in the form of a teardrop-shaped breast implant.

18. 15. The tissue product of claim 14, A tissue product characterized in that the suspension contains 2-4% by weight of solids.

19. 15. The tissue product of claim 14, selecting adipose tissue; processing the tissue to remove substantially all cellular material from the tissue; suspending the tissue in a liquid to form a suspension with a solids content of 2-4% by weight; and freezing and drying the suspension to form a porous sponge, wherein the implant is manufactured by a process comprising the steps of:

20. 15. The tissue product of claim 14, A tissue product characterized in that the suspension is stabilized by cross-linking.

21. 21. The tissue product of claim 20, A tissue product characterized in that the cross-linking is carried out using a dehydrothermal process.

22. 22. The tissue product of claim 21, A tissue product further comprising a chemical cross-linking step.

23. 23. The tissue product of claim 22, A tissue product, wherein the chemical crosslinking process includes at least one of glutaraldehyde, genepin, carbodiimide, and diisocyanate.

24. 23. The tissue product of claim 22, A tissue product wherein the crosslinking comprises heating.

25. 25. The tissue product of claim 24, A tissue product further comprising heating in a vacuum.

26. 26. The tissue product of claim 25, The tissue product further comprising heating to a range of 70°C to 120°C.

27. 23. The tissue product of claim 22, A tissue product characterized in that the suspension is crosslinked so that the implant maintains a stable three-dimensional structure when in contact with an aqueous environment.

28. 28. The tissue product of claim 27, A tissue product wherein the aqueous environment is a mammalian body.

29. 1. A method of treatment comprising: selecting an anatomical site requiring reconstruction, repair, augmentation or treatment; implanting a tissue product at or near the anatomical site, the tissue product comprising a breast implant, the implant comprising an acellular adipose tissue matrix construct comprising particulate acellular adipose tissue matrix that has been homogenized, dried, and stabilized to form a suspension, the implant measuring at least 5 cm in at least one dimension; and securing at least a portion of the tissue product at or near said anatomical site.

30. 30. The method of claim 29, The method, wherein the anatomical site is a breast.

31. 30. The method of claim 29, The method, wherein the anatomical site is the face, buttocks, abdomen, lower back, or thigh.

32. 30. The method of claim 29, The method wherein the anatomical site has undergone a mastectomy, lumpectomy, or cosmetic surgery.

33. 30. The method of claim 29, The method wherein the anatomical site is in need of treatment due to disease or trauma.

34. 30. The method of claim 29, A method comprising implanting a tissue product deep into said anatomical site to reinforce, reposition or outwardly project native tissue.

35. 30. The method of claim 29, The method further comprising growing native tissue within the tissue product.

36. 30. The method of claim 29, removing the tissue product; and implanting a second tissue product into the void created by the removal of the tissue product.

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