In vitro activation of human peripheral blood mononuclear cells induced by human biologic meshes

Abstract

Background: Inflammation and wound healing play critical roles in the integration of biologic meshes (BMs) at sites of hernia repair. Monocytes/macrophages (M/MQs) are key cells involved in mesh integration. Interleukin-1beta (IL-1beta) is one of the major M/MQ-derived cytokines, and its expression is a reflection of the degree of M/MQ activation. We hypothesized that BMs induce M/MQ activation in vitro and that IL-1beta expression by M/MQ varies among various BMs.

Materials and methods: Acellular human dermis-derived BM samples (AlloDerm, AlloMax, FlexHD) were placed in 48-well plates and cultured with peripheral blood mononuclear cells (PBMCs) from three healthy human subjects for 7 d. The resulting supernatants were assayed for IL-1beta levels by enzyme-linked immunosorbent assay (ELISA), and the BMs were evaluated histologically.

Results: IL-1beta expression varied among donors as well as the BMs [AlloDerm (2.11-38.25pg/10(6) PBMCs); AlloMax (13.12-715.40pg/10(6) PBMCs); and FlexHD (116.69-665.40pg/10(6) PBMCs)]. Analysis of this data indicated that AlloMax and FlexHD induced significantly more M/MQ activation compared with AlloDerm (P<0.05). Histologic evaluation of the BMs indicated adherence of M/MQs on BM surface, however no degradation was detected.

Conclusion: For the first time, we have demonstrated that M/MQs are activated to varying levels by human BMs in vitro. These differences may be related to BM processing technologies and/or the biologic variation between donors. Our results raise the possibility that these differences in M/MQ activation could result in varying intensity of inflammation and wound healing that control the integration of BMs at sites of hernia repair.