Comparative analysis of histopathologic responses to implanted porcine biologic meshes

Biologic mesh (BM) prostheses are increasingly utilized for hernia repairs. Modern BMs are not only derived from different tissue sources, but also undergo various proprietary processing steps-factors that likely impact host tissue responses and mesh performance. We aimed to compare histopathologic responses to various BMs after implantation in a mouse model.

Five-mm samples of non-crosslinked [Strattice (ST)], and intentionally crosslinked [CollaMend (CM), Permacol (PC)] porcine-derived biologic meshes were implanted subcutaneously in C57BL/6 mice. 1, 4, 8, and 12 weeks post-implantation, meshes were assessed for inflammation, foreign body reaction (FBR), neocellularization, and collagen deposition using H&E and trichrome stains.

All meshes induced early polymorphonuclear cell infiltration (highest in CM; lowest in ST) that resolved by 4 weeks. ST was associated with extensive macrophage presence at 12 weeks. Foreign body response was not seen in the ST group, but was present abundantly in the CM and PC groups, highest at 8 weeks. New peripheral collagen deposition was seen only in the ST group at 12 weeks. Collagen organization was highest in the ST group as well. Both CM and PC groups were associated with fibrous encapsulation and no evidence of integration or remodeling.

Inflammation appears to be a common component of integration of all biologic meshes studied. Pronounced inflammatory responses as well as profound FBR likely lead to observed encapsulation and poor host integration of the crosslinked BMs. Overall, ST was associated with the lowest foreign body response and the highest degree of new collagen deposition and organization. These features may be key predictors for improved mesh performance during hernia repair.