Bioengineered acellular dermal matrices for the repair of abdominal wall defects in rats

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.

Decellularized biologic muscle-fascia abdominal wall scaffold graft

BACKGROUND

Complex abdominal wall reconstruction using biologic mesh can lead to increased recurrence rates, nonincorporation, and high perioperative costs. We developed a novel decellularization method and applied it to porcine muscle fascia to mirror target-tissue architecture. The aims of this study were to analyze mechanical strength and tissue-graft incorporation.

METHODS

After serial decellularization, muscle-fascia mesh was created and tested for mechanical strength and DNA content. The muscle-fascia mesh was implanted subcutaneously in rats (n = 4/group) and the cohorts killed 1 to 4 weeks later. Explants were examined histologically or immunohistochemically.

RESULTS

Mechanical testing demonstrated equivalent strength compared with a commercially available biological mesh (AlloDerm), with mechanical strength attributable to the fascia component. Grafts were successfully implanted with no observable adverse events. Gross necroscopy revealed excellent subdermal scaffold engraftment. Microscopic evaluation identified progressive collagen deposition within the graft, neoangiogenesis, and presence of CD34 positive cells, in the absence of discernable graft rejection.

CONCLUSION

This study confirms a decellularization process can successfully create a DNA-free composite abdominal wall (muscle-fascia) scaffold that can be implanted intraspecies without rejection. Expanding this approach may allow exploitation of the angiogenic capacities of decellularized muscle, concomitant with the inherent strength of decellularized fascia, to perform preclinical analyses of graft strength in animal models in vivo.

Decellularization of Skin Tissue

Biomaterials science encompasses elements of medicine, biology, chemistry, materials, and tissue engineering. They are engineered to interact with biological systems to treat, augment, repair, or replace lost tissue function. The choice of biomaterial depends on the procedure being performed, the severity of the patient's condition, and the surgeon's preference. Prostheses made from natural-derived biomaterials are often derived from decellularized extracellular matrix (ECM) of animal (xenograft) or human (allograft) origin. Advantages of using ECM include their resemblance in morphology and three-dimensional structures with that of tissue to be replaced. Due to this, scientists all over are now focusing on naturally derived biomaterials which have been shown to possess several advantages compared to synthetic ones, owing to their biocompatibility, biodegradability, and remodeling properties. Advantages of a naturally derived biomaterial enhance their application for replacement or restoration of damaged organs/tissues. They adequately support cell adhesion, migration, proliferation, and differentiation. Naturally derived biomaterials can induce extracellular matrix formation and tissue repair when implanted into a defect by enhancing attachment and migration of cells from surrounding environment. In the current chapter, we will focus on the natural and synthetic dermal matrix development and all of the progress in this field.

Applications of decellularized materials in tissue engineering: advantages, drawbacks and current improvements, and future perspectives

Decellularized materials (DMs) are attracting more and more attention because of their native structures, comparatively high bioactivity, low immunogenicity and good biodegradability, which are difficult to be imitated by synthetic materials. Recently, DMs have been demonstrated to possess great potential to overcome the disadvantages of autografts and have become a kind of promising material for tissue engineering. In this systematic review, we aimed to not only provide a quick access for understanding DMs, but also bring new ideas to utilize them more appropriately in tissue engineering. Firstly, the preparation of DMs was introduced. Then, the updated applications of DMs derived from different tissues and organs in tissue engineering were comprehensively summarized. In particular, their advantages, drawbacks and current improvements were emphasized. Moreover, we analyzed and proposed future perspectives.

Selection of biological prosthesis for abdominal wall repair on the basis of in vitro biocompatibility determination

Research on prostheses for repairing abdominal wall defects has progressed through past decades for developing an ideal prosthesis. The study was designed to compare different extracellular matrix (ECM) derived biological prostheses as alternate to conventional synthetic polymeric prostheses for the repair of full thickness abdominal wall defects. Five biological scaffolds derived from bovine diaphragm, bovine aorta, bovine gall bladder, porcine gall bladder, and rabbit skin were prepared and screened for their in vitro biocompatibility. Decellularized ECMs were subjected to various biocompatibility analyses, namely, water absorption potential, matrix degradation analysis, biomechanical testing, and cytocompatibility analysis. Though the rabbit skin displayed maximum biomechanical strength, due to its rapid degradation, it failed to fulfill the criteria of an ideal prosthesis. ECMs derived from bovine diaphragm and aorta were found to be superior than others based upon hydration and matrix degradation analysis, with best scores for bovine diaphragm followed by bovine aorta. The bovine diaphragm and aorta also displayed sufficient biomechanical strength, with diaphragm being the second highest (next to rabbit skin), in biomechanical strength followed by aorta. None of the biological prosthesis revealed any cytotoxicity. Thus, bovine diaphragm and aorta derived ECM fulfill the necessary criteria for their use as biological prosthesis. Because these prostheses are biocompatible, apart from their low cost, ease of availability, and simple preparation, they present a potential alternative to synthetic prosthesis for repair of abdominal wall defects, especially in veterinary patients.

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio-Functionality to Meshes

Abdominal wall hernia is a recurrent issue world-wide and requires the implantation of over 1 million meshes per year. Because permanent meshes such as polypropylene and polyester are not free of complications after implantation, many mesh modifications and new functionalities have been investigated over the last decade. Indeed, mesh optimization is the focus of intense development and the biomaterials utilized are now envisioned as being bioactive substrates that trigger various physiological processes in order to prevent complications and to promote tissue integration. In this context, it is of paramount interest to review the most relevant bio-functionalities being brought to new meshes and to open new avenues for the innovative development of the next generation of meshes with enhanced properties for functional abdominal wall hernia repair.