Polypropylene (PP) meshes are widely used for repairing skeletal muscle defects like abdominal hernia despite the chances of undesirable pro-inflammatory tissue reactions that demand revision surgeries in about 45% of cases. Attempts have been made to address the problem by modifying the mesh surface and architecture. These procedures have yielded only incremental improvements in the management of overall postoperative complications, and the search for a clinically viable therapeutic strategy continues. This study deployed a tissue engineering approach for mitigating PP-induced adverse tissue reaction by dip-coating the mesh with a hydrogel formulation of the porcine cholecystic extracellular matrix (CECM). The biomaterial properties of the CECM hydrogel-coated PP (C-PP) meshes were studied and their biocompatibility was evaluated by in vitro and in vivo tests based on ISO standards. Further, the nature of tissue reactions induced by the hydrogel-coated mesh and a commercial PP hernia repair graft was compared in a rat model of partial-thickness abdominal wall defect. Histomorphologically, in comparison with the PP graft-induced tissue reaction, C-PP caused a favorable graft-acceptance response characterized by reduced numbers of pro-inflammatory M1 macrophages and cytotoxic lymphocytes. Remarkably, the differential inflammatory response of the C-PP graft-assisted healing was associated with a fibrotic reaction predominated by deposition of type I collagen rather than type III collagen, as desired during skeletal muscle repair. It was concluded that the CECM hydrogel is a potential biomaterial for surface modification of polymeric biomedical devices.
Keywords: M1 macrophage; biocompatibility; biomaterial; cytotoxic lymphocytes; hernia repair; type I/type III collagen ratio.