Impact of human umbilical cord-derived stem cells (HUMSCs) on host responses to a synthetic polypropylene mesh for pelvic floor reconstruction in a rat model

In order to evaluate the effects of human umbilical cord-derived stem cells (HUMSCs) on the biocompatibility of and tissue response to a polypropylene (PP) mesh (Gynemesh (TM) PS) implanted in rat vaginas, HUMSCs were isolated and characterized in vitro and then combined with Gynemesh (TM) PS to create a tissue-engineered mesh. This tissue-engineered mesh and pure PP mesh were implanted in the submucosae of the posterior vaginal walls of rats. Mesh/tissue complexes were harvested at 1, 4 and 12 weeks after implantation. Histological evaluations including an assessment of the inflammatory reaction, neovascularization and fibrosis around the mesh fibers were performed and real-time quantitative polymerase chain reaction (RT-PCR) was used to analyze the mRNA expression of genes involved in wound healing at the tissue-mesh interface. After being seeded onto the PP mesh scaffold, HUMSCs grew and proliferated well in vitro culture. One week after implantation, the HUMSC-seeded mesh elicited a greater inflammatory response than the pure PP mesh (3.33 +/- 0.21 vs. 2.63 +/- 0.18,p = 0.026), while 4 and 12 weeks after implantation, the inflammatory response in the HUMSC-seeded mesh was lower than that in the unseeded mesh (p < 0.05). At 12 weeks, the HUMSC-seeded mesh induced a lower expression of matrix metalloproteinase (MMP)-1 and a higher expression of anti-inflammatory cytokine interleukin (IL)-4. HUMSCs may decrease the inflammatory response and improve the biocompatibility of a conventional synthetic mesh and may have the potential to reduce postoperative complications such as mesh exposure or erosion.