Blood vessel matrix seeded with cells: a better alternative for abdominal wall reconstruction-a long-term study

The application of composite scaffold materials based on decellularized vascular matrix in tissue engineering: a review

Decellularized vascular matrix is a natural polymeric biomaterial that comes from arteries or veins which are removed the cellular contents by physical, chemical and enzymatic means, leaving only the cytoskeletal structure and extracellular matrix to achieve cell adhesion, proliferation and differentiation and creating a suitable microenvironment for their growth. In recent years, the decellularized vascular matrix has attracted much attention in the field of tissue repair and regenerative medicine due to its remarkable cytocompatibility, biodegradability and ability to induce tissue regeneration. Firstly, this review introduces its basic properties and preparation methods; then, it focuses on the application and research of composite scaffold materials based on decellularized vascular matrix in vascular tissue engineering in terms of current in vitro and in vivo studies, and briefly outlines its applications in other tissue engineering fields; finally, it looks into the advantages and drawbacks to be overcome in the application of decellularized vascular matrix materials. In conclusion, as a new bioactive material for building engineered tissue and repairing tissue defects, decellularized vascular matrix will be widely applied in prospect.

Preparation and Use of Decellularized Extracellular Matrix for Tissue Engineering

The multidisciplinary fields of tissue engineering and regenerative medicine have the potential to revolutionize the practise of medicine through the abilities to repair, regenerate, or replace tissues and organs with functional engineered constructs. To this end, tissue engineering combines scaffolding materials with cells and biologically active molecules into constructs with the appropriate structures and properties for tissue/organ regeneration, where scaffolding materials and biomolecules are the keys to mimic the native extracellular matrix (ECM). For this, one emerging way is to decellularize the native ECM into the materials suitable for, directly or in combination with other materials, creating functional constructs. Over the past decade, decellularized ECM (or dECM) has greatly facilitated the advance of tissue engineering and regenerative medicine, while being challenged in many ways. This article reviews the recent development of dECM for tissue engineering and regenerative medicine, with a focus on the preparation of dECM along with its influence on cell culture, the modification of dECM for use as a scaffolding material, and the novel techniques and emerging trends in processing dECM into functional constructs. We highlight the success of dECM and constructs in the in vitro, in vivo, and clinical applications and further identify the key issues and challenges involved, along with a discussion of future research directions.

Cell-based therapies for reinforcing the treatment efficacy of meshes in abdominal wall hernias：A systematic review and meta-analysis

To achieve a tension-free repair and reduce the recurrence rate of abdominal wall hernias (AWHs), various kinds of meshes have been applied in surgery. However, these meshes are reported to have problems with adhesion, infection, chronic pain and foreign body sensation. Recently, the introduction of cellular components on meshes seems to provide a new alternative to resolve these problems. This study aimed to evaluate the treatment efficacy of meshes seeded with cells (mesh-cell group) for AWHs, compared to meshes without cells (mesh group). Cochrane Library, Web of Science and PubMed were searched for studies that provided data about meshes, cells and AWHs. Twenty-six studies involving 578 animals were included. We found that the mesh-cell group could better control hernia recurrent than the mesh group (OR = 0.25, 95% CI = 0.15-0.42). Although the mesh-cell group did not reduce the incidence of adhesions (OR = 0.67, 95% CI = 0.26-1.74), it alleviated the extent of adhesions (WMD = -1.48, 95% CI = -1.86 to -1.10). In addition, the capillary density of mesh-cell group was also higher than that of mesh group (WMD = 26.27, 95% CI = 14.45-38.09). For incidence of infection, the two groups had no significant differences (OR = 0.94, 95% CI = 0.39-2.31). On the basis of our current evidence, AWHs were likely to receive a satisfied outcome in animal models when treated by meshes seeded with cells. Future studies with human trial data are needed to validate these findings.

The Effect of Adipose-Derived Stromal Vascular Fraction Cells to Abdominal Wall Fascia Defects in Rats: An Experimental Study

OBJECTIVE

Various synthetic and biological meshes have been developed to reduce recurrence and complications in ventral incisional hernia repairs. Adipose tissue is a rich reserve for mesenchymal stromal cells. In the present study we aimed to examine the effects of adipose-derived mesenchymal stromal cells (AD-MSCs) on abdominal incisional hernia repairs in rats.

MATERIALS AND METHODS

The study involved 32 male Wistar-Albino rats, weighing 200-250 g, which were divided into three groups. In Group 1 (control group) only an incisional hernia model was created. In Group 2, the incisional hernia model was created and 1 ml stromal vascular fraction (SVF), obtained from inguinal lipectomy material and containing mesenchymal stromal cells, was injected into the edges of the defect in the same session. In Group 3, only the incisional hernia model was created in the first stage and after 14 days, 1 ml of SVF was injected into the edges of the defect. Skin incisions of rats in Group 1 and 2 were opened on postoperative day 28 while in group 3 were opened on day 42. Peritoneal formation in abdominal wall defect was evaluated macroscopically and histopathologically.

RESULTS

Peritoneal formation was significantly superior in Groups 2 and 3 than in Group 1 (p: 0.031). In histopathological evaluation, the structural distortion and polymorphonuclear leukocyte (PMNL) levels were significantly higher in Group 1 than in Group 3 (p: 0.048 and p: 0.046, respectively). Granulation, capillary density, fibrosis and collagen organization were higher in Group 2 and 3, however this difference was not statistically significant (p > 0.05).

CONCLUSIONS

Adipose-derived stromal vascular fraction cells obtained from inguinal lipectomy material in rats positively affect the repair of abdominal incisional hernias by increasing peritoneal formation, and reducing structural distortion and PMNL infiltration.

The use of stem cells in aesthetic dermatology and plastic surgery procedures. A compact review of experimental and clinical applications

The aim of this paper was to collect currently available data related to the use of stem cells in aesthetic dermatology and plastic surgery based on a systemic review of experimental and clinical applications. We found that the use of stem cells is very promising but the current state of art is still not effective. This situation is connected with not fully known mechanisms of cell interactions, possible risks and side effects. We think that there is a big need to create and conduct different studies which could resolve problems of stem cells use for implementation into aesthetic dermatology and plastic surgery.

Evaluation of a Novel Hybrid Viable Bioprosthetic Mesh in a Model of Mesh Infection

Background:

The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of material used. Our laboratory previously showed that augmenting acellular bioprosthetic mesh with allogeneic mesenchymal stem cells (MSC) enhances resistance to bacterial colonization in vivo and preserves mesh integrity. This study’s aim was to determine whether augmentation of non-crosslinked porcine dermis (Strattice) with commercially available, cryopreserved, viable MSC-containing human placental tissue (Stravix) similarly improves infection resistance after inoculation with Escherichia coli (E. coli) using an established mesh infection model.

Methods:

Stravix was thawed per manufacturer’s instructions and 2 samples were tested for cell viability using a Live/Dead Cell assay at the time of surgery. Rats (N = 20) were implanted subcutaneously with 1 piece of Strattice and 1 piece of hybrid mesh (Strattice + Stravix sutured at the corners). Rats were inoculated with either sterile saline or 10⁶ colony-forming units of E. coli before wound closure (n = 10 per group). At 4 weeks, explants underwent microbiologic and histologic analyses.

Results:

In E. coli–inoculated animals, severe or complete mesh degradation concurrent with abscess formation was observed in 100% (10/10) hybrid meshes and 90% (9/10) Strattice meshes. Histologic evaluation determined that meshes inoculated with E. coli exhibited severe acute inflammation, which correlated with bacterial recovery (P < 0.001). Viability assays performed at the time of surgery failed to verify the presence of numerous live cells in Stravix.

Conclusions:

Stravix cryopreserved MSC-containing human umbilical tissue does not improve infection resistance of a bioprosthetic mesh in vivo in rats after inoculation with E. coli.

Abdominal wall regenerative medicine for a large defect using tissue engineering: an experimental study

PURPOSE

Treatment for a large abdominal wall defect remains challenging. The aim of this study was to optimize tissue engineering therapy of muscle constructs using a rat model.

METHODS

Experimental abdominal wall defects were created in Wister rats. The animal model was divided into three groups: collagen sponge (CS), hybrid scaffold (HS) and hybrid scaffold containing bone marrow liquid (HSBM). Hybrid scaffolds comprised collagen sponge and poly L-lactide (PLLA) sheets. Abdominal wall defects were covered by three kinds of sheets. Thereafter, the bone marrow liquid was spread onto the sheets. Rats were killed at 4, 8, and 16 weeks. Pathological examinations were performed using hematoxylin-eosin and desmin antibody staining.

RESULTS

The CS group showed abdominal hernia, whereas the HS and HSBM groups did not. Vascular formation was confirmed in all groups. Muscle tissue was recognized at the marginal area of the sheet only in the HSBM group.

CONCLUSION

The HS and HSBM groups show a greater intensity than the CS group. Muscle tissue regeneration is solely recognized in the HSBM group. Our experimental data suggest that the triad of scaffold, cell, and growth factor is fundamental for ideal biomaterials. The HSBM may be useful for reconstruction of abdominal wall defects.

Bone Marrow-Derived Mesenchymal Stem Cells Enhance Bacterial Clearance and Preserve Bioprosthetic Integrity in a Model of Mesh Infection

Background:

The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of the material used. Recently, mesenchymal stem cells (MSCs) have been shown to possess favorable immunomodulatory properties and improve tissue incorporation when seeded onto bioprosthetics. The aim of this study was to evaluate whether seeding noncrosslinked bovine pericardium (Veritas Collagen Matrix) with allogeneic bone marrow–derived MSCs improves infection resistance in vivo after inoculation with Escherichia coli (E. coli).

Methods:

Rat bone marrow–derived MSCs at passage 3 were seeded onto bovine pericardium and cultured for 7 days before implantation. Additional rats (n = 24) were implanted subcutaneously with MSC-seeded or unseeded mesh and inoculated with 7 × 10⁵ colony-forming units of E. coli or saline before wound closure (group 1, unseeded mesh/saline; group 2, unseeded mesh/E. coli; group 3, MSC-seeded mesh/E. coli; 8 rats per group). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses.

Results:

MSC-seeded meshes inoculated with E. coli demonstrated superior bacterial clearance and preservation of mesh integrity compared with E. coli–inoculated unseeded meshes (87.5% versus 0% clearance; p = 0.001). Complete mesh degradation concurrent with abscess formation was observed in 100% of rats in the unseeded/E. coli group, which is in contrast to 12.5% of rats in the MSC-seeded/E. coli group. Histologic evaluation determined that remodeling characteristics of E. coli–inoculated MSC-seeded meshes were similar to those of uninfected meshes 4 weeks after implantation.

Conclusions:

Augmenting a bioprosthetic material with stem cells seems to markedly enhance resistance to bacterial infection in vivo and preserve mesh integrity.