Biodegradable mesh implant for soft tissue repair, in particular hernia repair

Abstract

To provide a biodegradable mesh implant for use in soft tissue repair, in particular surgical hernia, chronic wound healing or fistula repair, within the body of a patient.SOLUTION: The present invention provides a biodegradable mesh implant for use in soft tissue repair, in particular surgical hernia, chronic wound healing or fistula repair, within the body of a patient. The mesh implant comprises a porous, hydrophilic biodegradable polymeric carrier mesh (10) and fibroblasts (16). The carrier mesh (10) comprises a sponge-like structure with interconnected pores of different sizes, it has a water contact angle of less than 75° and is made of at least a first polymer comprising polylactic acid as a main component.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a biodegradable mesh graft comprising a polymeric carrier mesh seeded with fibroblasts for use in soft tissue repair generally, and in particular for surgical hernia repair as claimed in claim 1. The present invention further relates to a method for preparing the mesh graft and a kit comprising the mesh graft of the invention and an additional polymeric support mesh. [Background technology]

[0002] Wound healing is a complex process involving a series of interrelated cellular events and the orchestration of a cytokine cascade. The main phases of wound healing include fibrin clot formation followed by infiltration of inflammatory cells and fibroblasts, development of granulation tissue and angiogenesis, and re-epithelialization. Growth factors and cytokines play a key role, supplied initially by degranulating platelets and later by fibroblasts and inflammatory cells, especially neutrophils and macrophages. Also, due to its complex nature, the wound healing process is fragile and sensitive to interruptions or failures, leading to the formation of chronic wounds where healing is severely impaired. Therefore, depending on the size and type of the soft tissue defect, surgical repair may be required to aid the wound healing process and reduce the risk of complications.

[0003] In the field of surgical soft tissue repair, mesh grafts are often used, consisting of resorbable or non-resorbable materials that are inserted to cover the area of ​​tissue damage, serving as a mechanical closure for the defect and providing a support structure for tissue regeneration, i.e., cell growth, which forms strong fibrous scar tissue around the mesh graft.

[0004] Apart from chronic wounds, mesh grafts are often used in surgical repair of hernia defects, especially of the abdominal wall, which may result from injury, tumor resection, or prolapse. In general terms, a hernia may be described as the passage of an organ or part of an organ outside the natural body cavity through a pre-created or acquired gap. The most frequently caused types of hernia are inguinal or femoral hernias, hiatal hernias, umbilical hernias, and incisional hernias, the latter of which are hernias that are pushed out through a post-surgical incision or procedure. In surgical hernia repair, the mesh graft is inserted and covers the area of ​​the defect in the abdominal wall, resulting in a closure without tensile strength, with or without suturing the surrounding muscles and fascia. This may be performed using open surgery or a minimally invasive approach laparoscopically under local or general anesthesia.

[0005] The reasons why hernias occur are still not fully understood. One theory presented in the field is that some patients have a genetic predisposition to develop recurrent hernias, especially in older patients, due to collagen metabolism disorders. It is believed that the altered ratio of collagen types I and III in these patients, along with an increase in collagen type III, reduces the mechanical strength of connective tissue. The reduced tensile strength of collagen type III is believed to play an important role in the development of incisional hernias, as seen in KLINGE, U. et al. Abnormal collagen I to III distribution in the skin of patients with incisional hernia. Eur Surg Res. 2000, vol. 32, no. 1, p. 43-48. It is also believed that impaired collagen production is a factor in the development of chronic wounds, i.e. wounds that do not heal properly and open repeatedly, especially in diabetic patients and patients with vascular disorders.

[0006] Commercially available meshes used in surgical soft tissue repair today are either non-degradable or sufficiently degradable to be absorbed by the patient's body after a period of time.

[0007] Non-resorbable mesh grafts are mostly made of various plastics and are known to remain biologically stable and safe for several years after implantation. However, introducing foreign materials into the human or animal body can be accompanied by side effects such as mesh migration, chronic inflammation, risk of infection, etc. Also, the introduction of relatively large plastic pieces into the body can induce a foreign body reaction brought about by the body's immune defense system. As a result, the mesh graft destroys and loosens the tissue that supports its function. A further problem is that the plastic materials used for the mesh, such as polypropylene, show limited cell proliferation stimulating effects. Therefore, cell growth at the defect site is often restricted and wound healing is delayed.

[0008] On the other hand, fully degradable (biodegradable) meshes have the advantage of not leaving foreign tissue in the body. Some fully degradable materials, such as polylactic acid (PLA) or collagen, have been shown to promote fibrosis, i.e., cell growth within the soft tissue defect, which is important for rapid and sustained wound healing. Nevertheless, if the mesh is degraded and absorbed too quickly, the scar plate gradually building up across the tissue defect will not be able to withstand the stresses still applied to the repaired soft tissue during daily activities. This is particularly important in the case of hernia repair, since the scar plate covering the defect must withstand intraperitoneal pressure, otherwise relapse of the hernia is mostly guaranteed. In addition, meshes made, for example, of PLA have the disadvantage of being rather brittle and prone to breaking when folded or rotated to introduce the mesh through laparoscopic tools. Summary of the Invention

[0009] The problem solved by the present invention is therefore to provide a mesh graft that allows for rapid, safe and stable closure of soft tissue defects, in particular in chronic wounds, fistula or hernia defects, while the components of the mesh graft should be easy and inexpensive to manufacture and accessible using conventional open and laparoscopic surgical methods.

[0010] This problem is solved by a mesh implant according to claim 1, a preparation method according to claim 11 and an implantation kit according to claim 15. Preferred embodiments are the subject of the dependent claims. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic representation of a section through a soft tissue defect that is repaired with the aid of a kit according to the invention.

[0012] [Diagram 2] FIG. 2 is a top view of a resected portion of an abdominal wall including a previous hernia area repaired with a kit of the present invention including a carrier mesh with fibroblasts and an additional support mesh.

[0013] [Figure 3A] Section through the abdominal wall of FIG. 2 along line A, i.e., through the area of ​​the previous hernia.

[0014] [Figure 3B] Enlarged detailed sections of FIG. 3A at 40× and 200× magnification, respectively. [Figure 3C] Enlarged detailed sections of FIG. 3A at 40× and 200× magnification, respectively.

[0015] [Figure 4A] Section through the abdominal wall of FIG. 2 along line B, i.e., proximal to the area of ​​the previous hernia.

[0016] [Figure 4B] Enlarged detailed section of FIG. 4A at 40x magnification.

[0017] [Figure 5A] Section through the abdominal wall of FIG. 2 along line C, i.e. away from the previous herniated area.

[0018] [Figure 6A] Detailed section at 40x magnification through a comparative abdominal wall in which the hernia area was repaired with a support mesh without fibroblasts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In accordance with the present invention, a mesh graft is provided for use in soft tissue repair within a patient's body, particularly surgical hernia or fistula repair or chronic wound healing. The mesh graft comprises a porous, hydrophilic, biodegradable polymeric carrier mesh made from a first polymer that comprises polylactic acid as at least a major component. The term "major component" thereby means that the PLA content of the first polymer is higher than the content of any additional polymers that the first polymer comprises.

[0020] The polymeric carrier mesh (which may hereinafter be referred to as the "carrier mesh") has a sponge-like structure with interconnected pores of different sizes and a water contact angle of less than 75°, meaning that it is hydrophilic. The mesh graft of the present invention (which may hereinafter be referred to as the "graft") further comprises fibroblasts present on or within the carrier mesh.

[0021] One important element of the present invention is that the carrier mesh is hydrophilic, even though it preferably contains as a major component poly(lactic acid) (commonly abbreviated as "PLA" or in the case of poly-L-lactic acid as "PLLA"), a biodegradable synthetic polymer that is generally hydrophobic in nature. Thanks to certain processing steps in the preparation of the carrier mesh, which are described in more detail further below, the carrier mesh can be provided with hydrophilic cell permeability and adhesion promoting properties that are important.

[0022] Another important element of the present invention is that the carrier mesh comprises fibroblasts. Surprisingly, it has been discovered that the formation of new tissue, particularly scar tissue, for closing soft tissue defects can be induced by bringing additional fibroblasts (of any origin, e.g. autologous, heterologous, xenophilic) into the defect area. Thus, instead of focusing on promoting tissue ingrowth of smooth muscle cells and fibroblasts from tissue adjacent to a chronic wound, fistula or hernia, for example, into a soft tissue defect, the implant of the present invention uses a degradable carrier mesh to bring an increased number of fibroblasts into the injury area. The fibroblasts help to constitute the extracellular matrix tissue and various types of collagen fibers, thereby forming a scar plate that closes the soft tissue defect. As such, the scar plate will form a firm connection between the degradable (and therefore temporary) polymer carrier mesh and the periphery of the injury and other surrounding structures (e.g. abdominal wall in the case of abdominal hernia), ensuring the desired support function by creating additional scar formation.

[0023] Within this application the following definitions apply: The term "biodegradable" means that the mesh can be absorbed over time when placed in vivo where it is surrounded by bodily fluids.

[0024] The term "mesh" as used throughout this application refers to a three-dimensional support or matrix, meaning a scaffold or sponge-like structure suitable for cell colonization. In this sense, the mesh serves as a three-dimensional template that can be colonized by cells or tissues. This colonization can occur in vitro or in vivo. Furthermore, in the context of implantation, the mesh serves to localize the implant and also as a placeholder for the gradually forming tissue in vivo.

[0025] The term "porous" thereby means a structure having holes, i.e. cavities or void areas. These holes may have a circular and / or angular shape in a two-dimensional cross-section, as well as an inclined shape when viewed in three dimensions. The shape of the holes may also be characterized by elongation, so that it can be compared to the shape of a nerve cell. Generally, the term "porous" means a cavity formed by filaments containing void areas, whereas a hole in the sense of the present invention is a cavity formed in a three-dimensional sponge-like structure. The cavity is thereby enclosed by a wall, as in natural sponges or corals. It is also meant that these holes or cavities can be interconnected, and that the wall of a hole between two adjacent holes may contain holes, forming a connection between said adjacent holes. In this regard, it is also meant that the hole may be formed by a void area between the granules of the hydrogel.

[0026] As mentioned above, the polymeric carrier mesh of the present invention has a three-dimensional, porous, sponge-like structure containing pores of different sizes, in contrast to a woven mesh structure, whereby at least some of the pores are interconnected and divide the space into a lattice-like network whereby they are fluidly connected, thus allowing the fibroblasts to spread throughout the mesh structure.

[0027] In the sense of the present application, as used in the context of the present invention, the term "hydrophilic" or "hydrophilic" as used herein means a water contact angle of the direct hydrophilic surface area on the carrier mesh that is less than 75°. Preferably, it means a contact angle of less than 60°.

[0028] As mentioned, biodegradable synthetic polymers, such as PGA or PLA, are generally hydrophobic, and the surfaces of porous scaffolds or meshes prepared from these polymers are therefore mostly hydrophobic. The hydrophilic properties of polymer meshes containing PLA as the main component can be amplified by post-treatment methods, such as plasma treatment (i.e., treatment with ionized gas plasma) and / or by covering the surface of the porous scaffold structure with natural polymers, such as collagen or gelatin.

[0029] The term "biocompatible polymer" means a polymer that is biologically tolerable and does not cause rejection when introduced into the body. For the purposes of the present invention, biocompatible polymers also include polymers that are recognized by the host as foreign, but whose rejection can be prevented by appropriate immunosuppression.

[0030] The term "biodegradable" refers to a material that can be converted into metabolizable products in a living organism (or in a fluid or cell culture derived from a living organism). Biologically degradable polymers include, for example, bioabsorbable and / or bioerodible polymers. "Bioerodible" refers to the ability to be dissolved or suspended in biological fluids. Bioabsorbable refers to the ability to be taken up by cells, tissues, or fluids of a living organism.

[0031] In preferred embodiments, the polymeric carrier mesh has a water contact angle of less than 40°, preferably less than 25°, more preferably less than 15°, and most preferably the water contact angle of the hydrophilic surface of the carrier mesh is in the range of 0° to 10° and is therefore "superhydrophilic".

[0032] The term "contact angle" as used in the context of the present invention refers to the contact angle of water on a surface, i.e. the angle formed at the interface where water meets the surface. The "water" used for contact angle measurement thereby refers to pure water, in particular ultrapure water. In particular, the contact angle measurement is carried out by the sessile drop method (e.g., using an EasyDrop DSA20E, Kruss GmbH device) with a drop size of 0.3 μL. The contact angle is generally calculated by fitting a bow function to the profile of a drop placed on the surface.

[0033] It has been found that the carrier mesh with hydrophilic properties promotes tissue ingrowth, for example of smooth muscle cells and fibroblasts from the tissue adjacent to the hernia defect, and even allows cell distribution on and through the mesh. In addition, the porous properties of the carrier mesh provide a growth-stimulating environment for cells that help build extracellular matrix tissue and various types of collagen fibers, thereby forming a scar plate that closes the hernia. The formation of the scar plate establishes a tight bond between the degradable (and therefore temporary) polymeric carrier mesh and the periphery of the hernia defect and the abdominal wall or other surrounding structures. Meanwhile, as the degradation of the carrier mesh continues, the newly formed scar tissue will provide the necessary support function by creating additional scarring, thereby preventing recurrent hernia formation. Finally, after complete degradation of the carrier mesh, i.e., when the polymeric component of the mesh is absorbed, no permanent foreign material will be left in the patient's body.

[0034] In a preferred embodiment, the carrier mesh has a flat plate-like shape and is elastically deformable, allowing it to be folded or rotated. In this embodiment, it is preferred that the carrier mesh is elastically deformable so that it can be folded or rotated and then return to its original shape. This allows for insertion of the rotated or folded mesh through a trocar in laparoscopic surgery.

[0035] When the carrier mesh is provided in a flat plate shape, it preferably has a thickness of at least 0.1 mm, more preferably at least 0.3 mm, even more preferably from about 1 mm to about 4 mm, and in some cases it may be thicker, for example up to 10 mm.

[0036] When provided in a sheet-like form, the cross-section of the carrier mesh can be of any type, e.g., rectangular, square, circular, oval, etc., and can be subsequently cut to conform to the shape of the hernia defect. For example, the overall shape of the cross-section can be circular or oval.

[0037] The carrier mesh may be in the form of one single continuous structure, or it may be provided in the form of multiple smaller pieces of mesh that are spaced apart from one another (i.e., "patches"). These small mesh patches may be included in paste, liquid, or semi-liquid formulations.

[0038] In another embodiment, the carrier mesh can be provided in the form of a hydrogel, i.e., without a specific three-dimensional profile or transverse shape. Due to its generally hydrophilic nature, the hydrogel supports tissue growth within its pores, thereby providing immediate fixation of the carrier mesh to the tissue. The hydrogel can also be mixed with additional substances, such as growth factors or medicamentously active substances.

[0039] With regard to the composition of the material of the carrier mesh, the carrier mesh is made solely of a first polymer comprising PLA as a major component, or is made of a first polymer and an additional natural polymer selected from the group consisting of collagen, gelatin, laminin, fibrinogen, albumin, chitin, chitosan, agarose, hyaluronic acidalginate, and mixtures thereof, with collagen being preferred.

[0040] Preferably, the sponge-like structure of the polymeric carrier mesh consists of a first polymer and is covered by at least one natural polymer. When the porous surface of the carrier mesh is coated or covered by a natural polymer, it is preferred that the porous structure of the lower part of the carrier mesh is not altered by the coating. In particular, the size of the pores is preferably not substantially altered, for example by forming an additional network within the pores of the carrier mesh. This ensures that the coating does not negatively affect the ability of fibroblasts to penetrate and spread within the carrier mesh. Further details on this subject are given in the further experimental section below.

[0041] It is further preferred that the natural polymer essentially covers all accessible surfaces of the carrier mesh (except for surfaces within closed pores), thus allowing cells to not only spread over the surface, but also within the porous structure of the carrier mesh.

[0042] Preferably, the first polymer is comprised of at least 70% poly(lactic acid), and even more preferably at least 80% poly(lactic acid). PLA has been found to have good tensile strength and high modulus. In addition, PLA has been found to be advantageous in terms of providing and maintaining hydrophilic properties obtained by plasma treatment and / or by covering the PLA structure with natural polymers such as collagen.

[0043] In this application, the term "polylactic acid (PLA)" includes, for example, poly-L-lactic acid (PLLA) or poly-D,L-lactic acid (a racemic mixture of L- and D-lactide; PDLLA). A specific example of a preferred first polymer is poly(L-lactide) having a molecular weight of 85,000 to 160,000, commercially available from Sigma Corporation (PLLA catalog number P1566). A suitable alternative is PLLA from Durect Corporation (Lactel® catalog number B6002-2).

[0044] More specifically, it has been found that for carrier meshes made of materials with a high PLA content, particularly when the first polymer is more than 50% PLA, e.g., at least 70% PLA, the hydrophilicity of the surface can not only be significantly increased by, for example, plasma treatment alone or in combination with covering the mesh with a natural polymer, but that the hydrophilicity can be maintained for an extended period of time.In fact, the hydrophilicity is believed to be maintained after sterilization of the carrier mesh with hydrogen peroxide (as described further below).This increase in hydrophilicity is not believed to be brought about by plasma treatment, for example, when the mesh has PGA as the main component.

[0045] While the first polymer can consist essentially of pure PLA, it can also be made of a mixture of PLA and other biodegradable materials, such as PGA. For example, the first polymer can consist of 75% PLA and 25% PGA (by weight of the first polymer). One reason for using a mixture of PLA and other biodegradable materials is that a pure PLA mesh is less strain resistant compared to a mesh made from PLA mixed with other polymers such as PGA. PGA is an abbreviation for polyglycolic acid. Copolymers of PLA and PGA, so-called lactic acid-glycolic acid copolymers (PLGA or PLG), are attractive candidates for fabricating biodegradable meshes due to their flexibility and well-defined physical properties and relative biocompatibility. In addition, their degradation products are low molecular weight compounds that enter normal metabolic pathways. Furthermore, PLGA copolymers offer the advantage of a wide range of degradation rates, ranging from days to years, by simply changing the copolymer ratio of lactic acid and glycolic acid.

[0046] In particular, if the mesh graft is intended for use in laparoscopic minimally invasive surgery, it must be insertable through laparoscopic tools such as trocars. For these applications, the carrier mesh is preferably in the form of a paste or hydrogel or alternatively in a shape that can be elastically folded or rolled for insertion through a laparoscopic tool. Elastic properties can be provided by using PLGA, a mixture of PLA and PGA, as the first polymer.

[0047] Therefore, for the collapsible carrier mesh, the first polymer is preferably made of PLGA, in particular a poly(lactic acid-glycolic acid) mixture having a lactic acid content of about 75 mol% and a glycolic acid content of about 25 mol%. Such a 75:25 poly(D,L-lactide-co-glycolide) material can be purchased, for example, as RESOMER® RG 752 from Evonik Industries AG (Essen, Germany) or from Sigma Corporation PLGA catalog number P1941. Further preferred polymer mixtures are poly(D,L-lactide-co-glycolide) 65:35, such as RESOMER® RG 653; poly(D,L-lactide-co-glycolide) 75:25, such as RESOMER® RG 502 or Durect company (Cupertino, CA, USA); poly(D,L-lactide-co-glycolide) 85:15, such as RESOMER® RG 858 or LACTEL® Absorbable Polymers.

[0048] Methods for preparing porous meshes from the mentioned synthetic polymers are well known in the art, for example the use of the salt leaching method as described in European Patent No. 2256155.

[0049] In a preferred embodiment, as stated, the carrier mesh consists essentially of the first polymer alone or the first polymer and an additional natural polymer selected from the group consisting of collagen, gelatin, laminin, fibrinogen, albumin, chitin, chitosan, agarose, hyaluronic acidalginate, and mixtures thereof. The natural polymer preferably covers all surfaces of the carrier mesh. In this way, the carrier mesh provides a hydrophilic, cell-friendly environment that enhances cell viability and proliferation rates, particularly on and within the mesh.

[0050] From the above mentioned natural polymers, collagen is most preferred. Collagen is a biomolecule of the extracellular matrix (ECM) and the main component of skin and bone. Thanks to its nanofibrous structure, collagen is particularly effective in promoting cell adhesion, growth and differentiation functions in tissue culture. It has also been found, however, that the hydrophilic properties of the carrier mesh according to the invention are particularly increased when the natural polymer comprises collagen. In this regard, the term "collagen" as used in the context of the present invention includes naturally occurring collagen and synthetically produced collagen and also collagen-derived substances, such as gelatin, which is a hydrolyzed form of collagen.

[0051] In a preferred embodiment, the natural polymer consists essentially of collagen. In this regard, the natural polymer can consist of only one collagen type, namely type I, or a mixture of collagen types, for example a mixture of collagen types I and IV. In the latter case, a mixture containing proteins in approximately equal weight percentages is preferably indicated. Collagen type I is the most preferred, since it is readily available, has a high degree of biocompatibility, and provides additional tensile strength. In addition, it is one of the main components of natural blood vessels and provides a natural adhesion site for cells involved in the wound healing process. And finally, degradation products of collagen types I-III have been shown to induce chemotaxis of human fibroblasts, which is particularly advantageous for the intended use of the carrier mesh as a graft containing fibroblasts.

[0052] Another advantage of the implants of the present invention is the ability to incorporate substances into the carrier mesh, such as collagen types IV and V, fibronectin, laminin, hyaluronic acid, and proteoglycans, and subsequently deliver them to the wound site to affect cell proliferation. Similarly, pharmacologically active substances, such as epidermal growth factor, platelet-derived growth factor, transforming growth factor beta, angiogenic factors, antibiotics, antifungals, spermicides, hormones, enzymes, and / or enzyme inhibitors, can be incorporated into the carrier mesh.

[0053] With regard to degradation of the carrier mesh in the body, which will mostly occur through bioabsorption of its components, it is preferred that it has a total in vivo degradation time of 1 to 12 months, preferably 1 to 8 months, more preferably about 1 to 6 months, and most preferably about 2 to 4 months.

[0054] To promote scar tissue formation, therefore, it is preferred that the carrier mesh further comprises a growth factor, preferably selected from the group consisting of interleukins, acidic fibroblast growth factor, basic fibroblast growth factor, epidermal growth factor, insulin-like growth factor, insulin-like growth factor binding protein, platelet-derived growth factor, transforming growth factor alpha, transforming growth factor beta, VEGF, and HGF. These growth factors are important for controlling cell proliferation and differentiation, protein synthesis, and ECM (extracellular matrix) remodeling. In particular, β-FGF, PDGF, VEGF, and HGF have been shown to increase granulation, epithelialization, and capillary formation through angiogenic cytokine secretion. They have also been shown to inhibit neutrophil and macrophage migration to the wound site by secreting factors that inhibit migration and suppress both IL-1α and IL-1β, and to secrete anti-inflammatory factors that prevent apoptosis and improve wound healing.

[0055] Preferably, the growth factors were added to the carrier mesh together with placental mesenchymal secretome. One preferred commercially available secretome is a secretome containing stem cells from human Wharton's jelly stem cells cultured under hypoxic conditions (CM-hWJSC). This stem cell secretome can be obtained from Stem Cell and Cancer Institute (PT. Kalbe Farma Tbk.). The secretome is used to stimulate the growth of cells implanted on the carrier mesh. Considering its use as a medical device, the addition of the secretome can be used ex vivo in an incubator to stimulate cell growth and implant. Once sufficient cell proliferation has been achieved, the mesh can be washed with culture medium before implantation.

[0056] The use of secretomes containing stem cells from human Wharton's jelly stem cells (CM-hWJSCs) cultured in hypoxic conditions to stimulate cell growth has been shown to be highly efficient not only for stimulating fibroblasts, but also for other cells, especially cells that are more sensitive to manipulation and culture, such as liver cells (hepatocytes). In fact, hepatocytes are commonly co-cultured with cells of the pancreas, especially cells of the islets of Langerhans, as this has been shown to increase the survival rate and proliferation rate of hepatocytes. When the described secretome is added to hepatocytes in the culture medium, the growth and proliferation of the stem cells was found to be even better than in co-culture with cells of the islets of Langerhans.

[0057] The fibroblasts provided on the carrier mesh are preferably autologous to the patient intended to receive the implantation, thus greatly reducing the risk of the patient mounting an undesirable immune response due to the implantation of xenogeneic cellular material.

[0058] The present invention also relates to a method for preparing such a mesh graft by the following steps: a) providing a biodegradable polymeric carrier mesh as described above; b) plasma treatment of the polymeric support mesh with an oxidizing gas plasma at a temperature below 50° C.; and c) Seeding the polymeric carrier mesh with fibroblast cells.

[0059] The plasma treatment was found to enhance the hydrophilic properties of the surface without adversely affecting the stability or structural integrity of the carrier mesh. Tests showed that the plasma treatment was effective to increase and also maintain the hydrophilic properties, especially when the polymer carrier mesh had a high PLA content, i.e., contained PLA as a major component. On the other hand, plasma treatment of PGA mesh did not significantly increase its hydrophilicity.

[0060] The ionizable gas plasma used for the plasma treatment is preferably selected from the group consisting of helium, argon, nitrogen, neon, silane, hydrogen, oxygen and mixtures thereof. The preferred treatment gas is oxygen.

[0061] The plasma treatment preferably comprises a low pressure plasma treatment, in which the carrier mesh is exposed to an ionized gas plasma at a temperature below 50° C., preferably below 40° C. The pressure is preferably 10 -2 ~10 -6 The pressure is in the range of 0.1 to 1.0 mbar.

[0062] The preferred treatment time is at least 1 minute, preferably 2 to 30 minutes, and more preferably 5 to 20 minutes.

[0063] The term "plasma" thereby generally refers to an excited and radicalized gas, i.e., a conductive process gas containing electrons and ions. Plasma is generally generated using electrodes in a vacuum chamber (so-called "RF plasma method"), but can also be generated by capacitive or inductive methods, or by using microwave radiation.

[0064] More preferably, the method for preparing the implant as described above comprises: a) providing a biodegradable polymeric carrier mesh as described above; b) covering at least the surface of the polymeric carrier mesh with a natural polymer, preferably collagen; c) plasma treatment of the polymeric support mesh with an oxidizing gas plasma at a temperature below 50° C.; and d) Seeding the polymeric carrier with fibroblast cells. The steps include:

[0065] Also, covering the polymeric carrier mesh with natural polymers, especially collagen, has been found to be very advantageous in view of increasing the hydrophilic properties of the surface of the mesh and using the carrier mesh as a carrier for cell growth.

[0066] It is particularly preferred that prior to seeding with fibroblasts, the polymeric carrier mesh is sterilized by treating it with H2O2 at a temperature below 50°C.

[0067] The sterilization step of the preparation method of the present invention is highly preferred for the preparation of the implant of the present invention. Surprisingly, it has been found that sterilization with hydrogen peroxide allows complete sterilization of the carrier mesh without using any conventional sterilization method, including hot steam, gamma radiation, electron beam irradiation or harsh chemical treatment, which have been shown to result in changes or further degradation of the molecular structure of the polymer carrier mesh and therefore reduce its mechanical and enzymatic resistance as well as its hydrophilic properties. In addition, the hydrogen peroxide sterilization method of the present invention preserves any collagen layer that may be provided on the carrier mesh. In contrast to conventional sterilization techniques that lead to denaturation of the collagen layer, especially in the case of nano-sized thick layers of collagen, H2O2 treatment as described above does not result in this degrading effect.

[0068] The sterilization time is highly dependent on the temperature and pressure in the chamber and the concentration of the H2O2 solution. Preferably, the H2O2 solution contains an amount of H2O2 of about 30% by volume or less. Preferred treatment times are at least 1 minute, preferably at least 5 minutes, or at least 1 hour. When "higher" pressures (e.g., about 10 mbar) and lower temperatures (e.g., less than 40° C.) or H2O2 concentrations of less than 30% by volume are applied, treatment times of up to 10-12 hours may be advantageous.

[0069] The hydrogen peroxide containing environment can be provided either by H2O2 plasma treatment or by placing the material to be sterilized in a vacuum chamber with a source of hydrogen peroxide (typically liquid). Upon application of a vacuum in the vacuum chamber, the hydrogen peroxide will sublime and an atmosphere containing hydrogen peroxide will be created. In addition, the negative pressure applied in the vacuum chamber is preferably less than 10 -6 ~10 -2 bar, more preferably 0.1 to 20.0 mbar, for example about 9 mbar.

[0070] To aid the wound healing process, the above method preferably comprises the additional step of providing a secretome, in particular a placental secretome, containing growth factors on or within a carrier mesh.

[0071] The present invention also relates to the use of the mesh implant of the present invention in primary wound closure, for example after a primary abdominal incision, to aid in wound healing, especially in the case of chronic wounds, and in the scarring process. In addition, it is also very suitable for use in the closure of fistulas or hernias.

[0072] In a further aspect, the present invention also relates to a method of closing a hernia using the above-mentioned implant. Generally, during said method, a degradable polymeric carrier mesh with seeded fibroblasts is placed over the defect, for example in the abdominal wall (inguinal hernia repair according to Lichtenstein), under the muscle layer of the abdominal wall (sub-lay technique), as an IPOM repair, or in any technique that the surgeon may deem appropriate for the repair.

[0073] Apart from hernias, the mesh graft of the present invention is also particularly well suited for the surgical closure of fistulas. A fistula is a pathological connection surrounded by epithelial tissue that connects the intraperitoneal cavity to the skin, has an opening at the level of the skin and often produces liquid that leaks through the skin, or a pathological connection between the large or small intestine and the anal region. Fistulas are difficult to treat surgically and tend to recur repeatedly. To date, complete excision of the entire fistula is the treatment of choice. Various materials have been developed to be inserted into the excised sulcus to improve the healing process. None of them guarantees long-term success. However, it has been found that the insertion or implantation of a carrier mesh with fibroblasts as described above substantially increases the healing process. This effect has also been seen in chronic wounds and fistulas. In this regard, consistent with the above, the carrier mesh can be in the form of a sheet or a shapeless hydrogel paste.

[0074] The present invention further relates to a kit for use in surgical soft tissue repair, particularly fistula or hernia repair, within a patient's body, wherein the kit comprises a) a polymeric carrier mesh as described above and b) an additional, preferably biodegradable, support mesh having a slower degradation rate than the polymeric carrier mesh.

[0075] If the support mesh is biodegradable, it preferably has a degradation rate within the range of 4 to 12 months.

[0076] A non-degradable or degradable support mesh is intended to be placed under the polymeric carrier mesh and bridge the hernia after the polymeric carrier mesh is degraded, which generally means that the support mesh will provide additional support function after the first trimester.

[0077] In a preferred embodiment, the support mesh is biodegradable and will degrade after a maximum of 12 months. Like the carrier mesh, the support mesh is preferably partially hydrophilic and therefore promotes the formation of a scar plate bridging the hernia.

[0078] Most preferably, the support mesh is a commonly available commercially available mesh.

[0079] In a preferred embodiment, the polymeric support mesh comprises one or more polymers from the group consisting of poly(glycolic acid), poly(lactic acid), poly(lactic-glycolic acid), and mixtures thereof. Also in this embodiment, if both the polymeric carrier mesh and the support mesh are biodegradable, then the carrier mesh preferably has a faster degradation rate than the support mesh.

[0080] In a further preferred embodiment, the kit comprises as a support mesh i) a hydrophilic layer facing the peritoneum or exposed abdominal musculature or fascia and having a water contact angle of less than 75°, preferably less than 60°; and ii) a hydrophobic layer having a water contact angle greater than 90° The present invention further includes an additional bilayered anti-adhesion mesh comprising two individual or composite layers consisting of:

[0081] This embodiment of the implant kit offers two main advantages: on the one hand, the polymeric carrier mesh provides a temporary closure of the injury, especially a hernia or fistula, and on the other hand, the fibroblasts form new scar tissue that takes over the support function after the degradation of the carrier mesh. The bilayered anti-adhesion mesh, which serves as a support mesh, has on the one hand an upper layer with hydrophilic properties that promotes tissue growth on the side facing the soft tissue defect, especially the proliferation of the implanted fibroblasts that help to form a scar plate that gradually closes the injury, and on the other hand a lower layer with hydrophobic properties that prevents the attachment of various cells, especially inflammatory cells, fibrin or debris, to the anti-adhesion mesh from the inner side of the abdominal cavity, i.e., the side of the support mesh facing away from the injury, such as the occurrence of inflammation and the formation of adhesion tissue growth between the anti-adhesion mesh or the newly formed scar plate and the underlying abdominal tissue.

[0082] Although the support mesh is generally described as having a lower degradation rate than the carrier mesh, it may also be that a portion of the support mesh has a similar degradation rate to one of the carrier meshes. For example, in the embodiment, the support mesh has an upper layer and a lower layer as defined in the paragraph above, and the upper layer may have a faster degradation rate than the lower layer, such that the degradation time of the upper layer in vivo is between 1-3 months, preferably about 2 months, and the degradation time of the lower layer in vivo is between 4-8 months, preferably about 6 months. This means that in this bilayered embodiment, it is the lower layer of the support mesh that provides additional support function mostly during the first 4-8 months. After this time, the lower layer will preferably degrade as well.

[0083] Considering their use in hernia or fistula repair, it is preferred that at least one, and preferably both, of the polymeric carrier mesh and the support mesh be flexible to allow it / them to be inserted into the patient's body via laparoscopic tools.

[0084] Each of the polymeric carrier mesh and the support mesh can be provided in any shape, e.g., rectangular, square, circular, oval, etc., and subsequently cut to fit the shape of the hernia defect. Alternatively, the mesh can have a generally square or rectangular shape. Alternatively, the support mesh can be flat in shape, and the carrier mesh can be a substitute for a paste or hydrogel containing fibroblasts. In this way, the support mesh holds the carrier mesh in place while the carrier mesh can be used to fill the soft tissue defect.

[0085] When used to close a hernia, the implant kit of the present invention may be used as follows:

[0086] First, an implantation kit as described above is provided. An incision is then made through the patient's skin and tissue to approximate the intraperitoneal defect. The polymeric support mesh is then placed over the defect, for example either in the abdominal wall (inguinal hernia repair according to Lichtenstein) or alternatively sub-peritoneally as a sub-muscular layer of the abdominal wall (sub-lay technique) or IPOM (intraperitoneal on lay mesh), and a polymeric carrier is placed on top of the support mesh. If provided in a flat shape, the carrier mesh can additionally be attached to abdominal muscles. The incision is then closed.

[0087] The hernia defect will be closed within 3-6 months, usually by a scar plate, as the biodegradable carrier mesh gradually loses its strength and rigidity, and ultimately no permanent foreign body material will remain as the mesh components are bioabsorbable in the body. EXAMPLES

[0088] Preparation of carrier mesh

[0089] Sodium chloride (NaCl) particles were crushed using a mortar and pestle and sieved to obtain NaCl particles in the range of 355-425 μm. 9 g of NaCl particles were placed in a centrifuge tube and dried in a desiccator. The NaCl particles were then placed in an aluminum pan.

[0090] The PLLA solution, prepared by dissolving 1 g of PLLA pellets in 5 mL of chloroform, was mixed with NaCl microparticles, and the mixture was then evenly spread on an aluminum pan to form a flat PLLA layer. The solvent was evaporated by air drying at room temperature for 20-48 hours, preferably 24-36 hours, most preferably 28-32 hours. Meanwhile, the solvent evaporation was carried out in a controlled temperature oven and placed in a fume hood to remove the toxic chloroform gas.

[0091] The pre-dried PLLA-NaCl layer was separated from the aluminum pan and dried in a vacuum chamber with a negative pressure of 0.1 MPa for 3-4 days.

[0092] The resulting dried PLLA layer was placed in a beaker and the NaCl microparticles were leached out by washing the matrix with deionized water. Finally, the matrix was immersed in ddH2O (double distilled water) and kept in a linear shaking bath at 25°C (room temperature) and 60 rpm for 48 hours. The water in the beaker was changed every 1-2 hours. The thus prepared PLLA mesh was removed from the beaker and dried overnight in a fume hood.

[0093] Post-treatment with collagen

[0094] The PLLA meshes were cut into circles with a diameter of 1 cm. Each PLLA mesh was then immersed in type I collagen acidic solution (purchased from Wako, 1.0 (w / v)%, pH 3.0) under vacuum to fill the pores of the mesh with collagen solution. To remove any excess collagen solution in the PLLA meshes, they were placed in a centrifuge tube, and the tube was centrifuged at a centrifugal acceleration of 2000 g for 10 minutes. It was found that an acceleration of more than 600 g provided a PLLA mesh coated with collagen instead of forming collagen microsponges in the pores.

[0095] The collagen-PLLA mesh was subsequently frozen at -80° for 12 hours and lyophilized under reduced pressure of <5 Pa for an additional 24 hours to remove any solvent from the mesh.

[0096] When a crosslinking agent was used (which was shown not to be essential for the preparation of the mesh), the collagen-PLLA mesh was further crosslinked by treatment with glutaraldehyde vapor saturated with 25% aqueous glutaraldehyde solution at 37°C for 4 hours. After crosslinking, the mesh was treated with 0.1 M aqueous glycine solution to block unreacted aldehyde groups. Instead of glycine, other blocking agents could be used, such as casein, albumin, gelatin or anhydrous methanol-acetic anhydride. After washing with deionized water and lyophilization, the polymer carrier mesh was obtained as the final product. After lyophilization (also known as freeze-drying), the collagen-PLLA mesh was stored in a desiccator until use.

[0097] The carrier mesh was prepared with holes having diameters in the range of 50 to 900 micrometers, preferably 280 to 560 micrometers, and most preferably 355 to 425 micrometers.

[0098] Notably, the pores in the PLLA mesh had essentially the same shape as the NaCl particles. Collagen coating of the PLLA mesh thereby only altered the hydratability (hydrophilicity) of its surface but did not change the structure of its pores.

[0099] Compared to uncoated PLLA mesh, the collagen-coated PLLA mesh demonstrated both improved hydration and high water absorbency.

[0100] O2 Plasma Treatment

[0101] The carrier mesh, either collagen coated or not, was optionally subjected to plasma treatment using an ionized gas plasma, preferably selected from the group consisting of helium, argon, nitrogen, neon, silane, hydrogen, oxygen and mixtures thereof, preferably using plasma treatment using ionized oxygen, hydrogen or nitrogen gas plasma.

[0102] The plasma treatment was carried out in a vacuum chamber for a time period of 5-20 min, preferably 8-15 min, using a plasma treatment device from Diener (Diener electronics; Plasma-Surface-Technology; Ebhausen, Germany). The treatment parameters were set as follows: pressure in the vacuum chamber: 0.40 mbar; power: 35 W; oxygen gas flow rate: 5 sccm (min) to 60 sccm (max).

[0103] sterile

[0104] Finally, the carrier meshes were subsequently sterilized by placing them in an H2O2-containing environment by exposing the carrier meshes to an H2O2-containing atmosphere.

[0105] The H2O2-containing environment or atmosphere was created in a vacuum chamber by placing the carrier mesh in the chamber together with an open flask containing H2O2 solution, followed by evacuating the chamber and evaporating the H2O2. The H2O2 solution contained H2O2 in an amount of 30% by volume. The treatment time is highly dependent on the pressure in the chamber and the concentration of the H2O2 solution. Preferably, the sterilization time was 10-12 hours, at a temperature of 40°C and a pressure of about 9 mbar. However, lower pressures or temperatures, as well as treatment times of only a few minutes, have been shown to be effective.

[0106] Static contact angle measurement, droplet method

[0107] Contact angle measurements were performed to determine the degree of hydrophilicity or hydrophobicity. In most cases, the contact angle of the mesh was determined. It was determined by static contact angle measurements using a drop test with ultrapure water (EasyDrop DSA20E, Kruss GmbH). A water drop with a size of 0.3 μL was dispensed using an automated unit. The contact angle value was calculated by fitting a bow function to the contour of the drop placed on the surface.

[0108] Fibroblast harvest, culture and seeding

[0109] Harvesting of fibroblasts was performed by dermatological or surgical excision of full thickness skin samples under strict sterile conditions, approximately 2 cm x 1 cm. The samples were placed in a sterile container and covered with pre-warmed PBS containing 2% antibiotic / antimycotic (AB / AM). The samples were transferred to the laboratory where they were washed with pre-warmed wash / EGTA solution containing 2% AB / AM. The washed skin samples were covered with freshly prepared complete DMEM medium containing 200 Units / mL collagenase, 10-20% PBS, 2% AB / AM, 2 mM L-glutamine and 1 mM sodium pyruvate solution, and then incubated dermis side down at 37°C with 5% CO2 for 3-5 hours. The dermis side was gently scraped with a cell scraper until all of the dermis side was dissolved in the collagenase solution. The dermis was discarded and the cell suspension was sieved through a 100 μm nylon cell sieve, and the cells collected in the sieve were thoroughly rinsed with PBS (2% AB / AM) and collected in a centrifuge tube. The cells were centrifuged for 10 min, the supernatant was discarded, and the cells were resuspended in complete DMEM medium containing 10-20% FBS, 2% AB / AM, 2 mM L-glutamine, 1 mM sodium pyruvate, and 10 mM HEPES. The resuspended cells were added to a collagen-coated flask and incubated at 37°C, 5% CO2 for 30 min. Fibroblasts attached to the collagen-coated surface of the flask were separated from non-fibroblast cells that remained in the culture medium. Cell counts were performed by trypan blue staining.

[0110] Fibroblasts were cultured in DMEM medium if desired. The carrier mesh was seeded with fibroblasts (1 cm 2 (500,000 cells per well).

[0111] The collagen coating was found to increase the hydration of the porous surface of the carrier mesh and promote the penetration of the cell suspension solution, allowing the fibroblasts to easily penetrate into the internal pores of the carrier mesh.

[0112] Preferred embodiments of the construction of the implant of the present invention and its placement within a patient's body for soft tissue repair are further described with reference to the accompanying drawings, in which:

[0113] In FIG. 1 a schematic diagram of a section through a soft tissue defect to be repaired with the aid of a kit according to the invention is shown.

[0114] The schematic diagram of FIG. 1 shows a defect (gap) in muscle tissue 12 to be filled by a mesh graft 10 of the present invention. Specifically, a commercially available support mesh 14 is placed under the defective muscle layer 12, and a polymeric biodegradable carrier mesh 10 containing fibroblasts 16 is inserted into the defect. The underlying skin 17 is then repaired, i.e., closed by sutures 18. The carrier mesh provides a temporary structure for the proliferation of fibroblasts and for the growth of cells from adjacent tissue. Typically, the carrier mesh 10 with fibroblasts 16 will simply be inserted into or placed across the defect. Thanks to the support mesh 14, displacement of the carrier mesh 10 from the implantation site is protected.

[0115] Over the course of days to weeks after insertion of the mesh graft, fibroblasts deposited on the carrier mesh within the muscle tissue defect continued to proliferate and spread into adjacent tissue. This was demonstrated by fibroblasts spreading into the adjacent muscle tissue and into the support mesh beneath the defect. The foreign fibroblasts were shown to produce collagen, which helps to build scar tissue that tightly closes the defect in the muscle tissue until the carrier mesh is sufficiently degraded.

[0116] The mesh implants of the present invention were also tested in vivo in rats, as described in the following section.

[0117] histology

[0118] Experimental abdominal wall hernias in rats were repaired with a biodegradable mesh graft according to the present invention, i.e., a carrier mesh with fibroblasts. In this study, a hernia in the muscle tissue of the abdominal wall was closed with a support mesh of the present invention having a large number of fibroblasts and secretomes added to the carrier mesh. To keep the implanted carrier mesh in place, two additional support meshes were implanted as part of the kit of the above-mentioned invention, one above and one below the hernia in the muscle tissue. Histological analysis of the skin injury site is shown in Figures 2-6A:

[0119] In FIG. 2, a top view of a resected portion of abdominal wall including a previous hernia area repaired with a kit of the present invention including a carrier mesh with fibroblasts and an additional support mesh is shown;

[0120] In Fig. 3A, a section is shown through the abdominal wall of Fig. 2 along line A, i.e. through the area of ​​the previous hernia;

[0121] In Figures 3B-C we show enlarged detailed sections of Figure 3A at 40x and 200x magnifications, respectively;

[0122] In Fig. 4A, a section is shown through the abdominal wall of Fig. 2 along line B, i.e. close to the area of ​​the previous hernia;

[0123] In Fig. 4B we show an enlarged detailed section of Fig. 4A at 40x magnification;

[0124] In Fig. 5A, a section is shown through the abdominal wall of Fig. 2 along line C, i.e. away from the previous herniated area;

[0125] FIG. 6A shows a detailed section at 40x magnification through a comparative abdominal wall in which the hernia area was repaired with a support mesh without fibroblasts.

[0126] 2, the abdominal wall includes layers of epidermis 20, dermis 22, subcutaneous tissue 24 with fat cells, muscle tissue 26, and a previous herniated area 28 into which a carrier mesh and support mesh have been implanted within muscle area 26. Thus, the previous gap within muscle tissue 26 has been filled by the carrier mesh (and fibroblasts).

[0127] In Figures 3A-3C an enlarged section of the former herniated area 28 is shown. Within this area 28 a tissue mass 29 is visualized that has occluded the former hernia and consists of at least a portion of the partially degraded carrier mesh 10. In this mass 29 a population 32 of mesenchymal-like cells (elongated and round cells) are arranged in interwoven bundles and also fibroblasts 16 of radial to needle-like shape, each with an oval-flat nucleus with a clear border and finely granular chromatin, can be seen. The mesenchymal cells 32 are believed to originate from a secretome deposited on the carrier mesh together with the fibroblasts 16. Intermixed with the mesenchymal cells 32 are collagen fibers 38. Adipose tissue 30 is visible underneath the fibroblast / collagen / mesenchymal-like cell mass 29. A re-epithelialized area 40 above the mass 29 is visualized separating the mass 29 from several layers of epithelial cells with orthogonal hyperkeratosis and pustular re-epithelialization within the cornea. Remnants of the support mesh 14 can be seen underneath the mass 29 at the border of the muscularis region 26 and the adipose tissue 30 (FIG. 3C).

[0128] Mostly, fibroblasts are found in lower numbers and predominantly in the subcutaneous region. The large number and location of the identified cells strongly implies that these radial to needle-like shaped fibroblasts 16 originate from the implanted carrier mesh 10.

[0129] Confirmation of the above observations is shown in Figures 4A-6A: Figures 4A and 4B show a section through the repaired abdominal wall of Figures 3A-C, but the cut is not made through the previous hernia 28, but adjacent to it. In this adjacent area, only the support mesh 14 is present, as it not only covers the herniated area 28, but also the adjacent area around it. The support mesh 14 is still clearly visible above and below the muscle layer 26. In contrast to the sections shown in Figures 3A-3C, no carrier mesh is present.

[0130] On the other hand, Figure 5A shows a section through tissue away from the herniated area, i.e. through the normal tissue of the abdominal wall, and as expected, no support or carrier mesh is visible.

[0131] In FIG. 6A, results from a control study are shown in which a carrier mesh 10 without fibroblasts was implanted to close a soft tissue defect in the abdominal wall of a rat. In this control study, the radial to needle-like shaped cells defined in the tissue sections shown in FIGS. 3A-3C (and not in FIG. 6A) were confirmed to be fibroblasts that did not originate from the tissue. Therefore, the results of this histological study confirmed that the presence of fibroblasts was fibroblasts originating from the implant and not due to the wound healing and inflammatory processes that normally occur. In addition, the fibroblasts not only remained at the site of the carrier mesh, but also actively migrated into the adjacent host tissue where they supported collagen formation, which is believed to lead in a stepwise manner to improved scar formation.

[0132] Therefore, histological analysis not only demonstrated the distribution of the implanted fibroblasts within the soft tissue defect, but also demonstrated ingrowth and migration of the fibroblasts into the adjacent tissue.

Claims

1. 1. A biodegradable mesh graft for use in soft tissue repair, particularly surgical hernia repair, chronic wound healing or fistula repair, within a patient's body, said mesh graft comprising: A porous, hydrophilic, biodegradable polymeric carrier mesh (10), and containing fibroblasts (16) on or within said polymeric carrier mesh; wherein said carrier mesh (10) comprises a sponge-like structure having interconnected pores of different sizes, has a water contact angle of less than 75°; and A biodegradable mesh graft made from at least a first polymer that includes polylactic acid as a major component.

2. The implant of claim 1, wherein the polymeric carrier mesh has a water contact angle of less than 40°, preferably less than 25°, more preferably less than 15°, and most preferably in the range of 0° to 10°.

3. The implant of claim 1 or 2, wherein the carrier mesh has a flat shape and is elastically deformable, allowing it to fold or rotate.

4. The implant of any one of claims 1 to 3, wherein the first polymer is at least 70% poly(lactic acid), more preferably at least 80% poly(lactic acid) or consists essentially of poly(lactic acid).

5. The implant according to any one of claims 1 to 4, wherein the polymeric carrier mesh is composed of the first polymer alone or the first polymer and at least one natural polymer selected from the group of collagen, gelatin, laminin, fibrinogen, albumin, chitin, chitosan, agarose, hyaluronic acidalginate and mixtures thereof, where collagen is preferred.

6. The implant of claim 5, wherein the sponge-like structure of the polymeric carrier mesh is covered by at least one natural polymer, preferably collagen.

7. The implant according to any one of claims 1 to 6, wherein said carrier mesh has a total in vivo degradation time of 1 to 12 months, preferably 1 to 8 months, more preferably about 1 to 6 months, and most preferably about 2 to 4 months.

8. The graft according to any one of claims 1 to 7, wherein said fibroblasts are autologous fibroblasts of the patient intended to receive said graft.

9. 9. The implant according to any one of claims 1 to 8, further comprising a growth factor, preferably selected from the group consisting of interleukins, acidic fibroblast growth factor, basic fibroblast growth factor, epidermal growth factor, insulin-like growth factor, insulin-like growth factor binding protein, platelet derived growth factor, transforming growth factor alpha, transforming growth factor beta, VEGF and HGF.

10. The implant of claim 8 , wherein the growth factor is a growth factor in the placental mesenchymal secretome.

11. a) providing a biodegradable polymeric carrier mesh comprising a sponge-like structure with interconnected pores of different sizes having a water contact angle of less than 75° and made from at least one first polymer comprising polylactic acid as a main component; b) plasma treatment of the polymeric support mesh with an oxidizing gas plasma at a temperature below 50° C.; and c) Seeding the polymeric carrier mesh with fibroblast cells. A method for preparing a mesh graft according to claims 1 to 10, comprising the steps of:

12. a) providing a biodegradable polymeric carrier mesh comprising a sponge-like structure with interconnected pores of different sizes having a water contact angle of less than 75° and made from at least one first polymer comprising polylactic acid as a main component; b) covering at least said surface of said polymeric carrier mesh with a natural polymer, preferably collagen; c) plasma treating the polymeric support mesh by treating the polymeric support mesh with an oxidizing gas plasma at a temperature less than 50° C.; and d) Seeding the polymeric carrier mesh with fibroblast cells. The method of claim 11 , comprising the steps of:

13. Prior to seeding with fibroblasts, the polymeric carrier mesh is heated at a temperature of less than 50° C. in H ２ O ２ 13. The method according to claim 11 or 12, wherein the method is sterilized by treating it with

14. The sterilization step is 10 －２ ~10 －６ bar, preferably in the range of 0.1 to 20.0 mbar, for at least 1 minute, preferably at least 5 minutes. ２ O ２ By treating the polymeric carrier mesh with plasma or by treating the carrier mesh with H ２ O ２ 14. The method of claim 13, carried out by exposure to a containing atmosphere.

15. The method according to any one of claims 11 to 14, further comprising the step of adding a secretome containing growth factors onto the carrier mesh.

16. 1. An implantation kit for use in surgical wound repair, in particular fistula or hernia repair, within a patient's body, said implantation kit comprising: A mesh graft comprising a biodegradable polymer carrier mesh having fibroblasts according to any one of claims 1 to 10, and a polymeric support mesh comprising one or more polymers selected from the group consisting of poly(glycolic acid), poly(lactic acid), poly(lactic-glycolic acid), and mixtures thereof; where The implant kit, wherein the polymeric carrier mesh has a faster degradation rate than the support mesh.

17. 17. The transplant kit of claim 16, further comprising an anti-adhesion mesh comprising two individual or composite layers: a hydrophilic layer facing the abdominal muscle tissue and having a water contact angle of less than 75°, preferably less than 60°, and a hydrophobic layer having a water contact angle of more than 90°.

18. 18. The transplant kit of claim 16 or 17, wherein the support mesh has a flat shape and the polymeric carrier mesh is in the form of a paste or hydrogel that contains the fibroblasts.

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