Investigation of the regenerative capacity of an acellular porcine medial meniscus for tissue engineering applications.

Previously, we have described the development of an acellular porcine meniscal scaffold. The aims of this study were to determine the immunocompatibility of the scaffold and capacity for cellular attachment and infiltration to gain insight into its potential for meniscal repair and replacement. Porcine menisci were decellularized by exposing the tissue to freeze-thaw cycles, incubation in hypotonic tris buffer, 0.1% (w/v) sodium dodecyl sulfate in hypotonic buffer plus protease inhibitors, nucleases, hypertonic buffer followed by disinfection using 0.1% (v/v) peracetic, and final washing in phosphate-buffered saline. In vivo immunocompatibility was assessed after implantation of the acellular meniscal scaffold subcutaneously into galactosyltransferase knockout mice for 3 months in comparison to fresh and acellular tissue treated with α-galactosidase (negative control). The cellular infiltrates in the explants were assessed by histology and characterized using monoclonal antibodies against: CD3, CD4, CD34, F4/80, and C3c. Static culture was used to assess the potential of acellular porcine meniscal scaffold to support the attachment and infiltration of primary human dermal fibroblasts and primary porcine meniscal cells in vitro. The explants were surrounded by capsules that were more pronounced for the fresh meniscal tissue compared to the acellular tissues. Cellular infiltrates compromised mononuclear phagocytes, CD34-positive cells, and nonlabeled fibroblastic cells. T-lymphocytes were sparse in all explanted tissue types and there was no evidence of C3c deposition. The analysis revealed an absence of a specific immune response to all of the implanted tissues. Acellular porcine meniscus was shown to be capable of supporting the attachment and infiltration of primary human fibroblasts and primary porcine meniscal cells. In conclusion, acellular porcine meniscal tissue exhibits excellent immunocompatibility and potential for cellular regeneration in the longer term.

Development and characterization of an acellular porcine medial meniscus for use in tissue engineering.

The objectives of this study were to characterize fresh porcine menisci and develop a decellularization protocol with a view to the generation of a biocompatible and biomechanically functional scaffold for use in tissue engineering/regeneration of the meniscus. Menisci were decellularized by exposing the tissue to freeze-thaw cycles, incubation in hypotonic tris buffer, 0.1% (w/v) sodium dodecyl sulfate in hypotonic buffer plus protease inhibitors, nucleases, hypertonic buffer followed by disinfection using 0.1% (v/v) peracetic acid and final washing in phosphate-buffered saline. Histological, immunohistochemical, and biochemical analyses of the decellularized tissue confirmed the retention of the major structural proteins. There was, however, a 59.4% loss of glycosaminoglycans. The histoarchitecture was unchanged, and there was no evidence of the expression of the major xenogeneic epitope, galactose-alpha-1,3-galactose. Biocompatibility of the acellular scaffold was determined by using contact cytotoxicity and extract cytotoxicity tests. Decellularized tissue and extracts were not cytotoxic to cells. Biomechanical properties were determined by indentation and tensile tests, which confirmed the retention of biomechanical properties following decellularization. In conclusion, this study has generated data on the production of a biocompatible, biomechanically functional scaffold for use in meniscal repair.