Development and in vitro investigation of a biodegradable mesh for the treatment of stress urinary incontinence.

INTRODUCTION AND HYPOTHESIS: The use of polypropylene (PP) mesh for stress urinary incontinence (SUI) surgery has declined because of safety concerns. The aim of this study is to evaluate a biodegradable polycaprolactone (PCL) mesh and a PCL composite mesh tissue engineered with human uterine fibroblasts (HUFs) for SUI surgery by comparing mechanical properties and in vitro biocompatibility to commercially available PP and porcine dermis (PD). METHODS: The mechanical properties of four scaffold materials were evaluated: PCL, PCL-collagen-hyaluronic acid composite, acellular porcine dermal collagen (PD) (Pelvicol™) and polypropylene (Gynecare TVT™ Exact®). HUFs were seeded on separate scaffolds. After 7 and 14 days scaffolds were assessed for metabolic activity and cell proliferation using Alamar Blue, Live/Dead and PicoGreen assays. Soluble collagen production was evaluated using a Sircol assay. RESULTS: PCL and the composite scaffold reached ultimate tensile strength (UTS) values closest to healthy pelvic floor tissue (PCL = 1.19 MPa; composite = 1.13 MPa; pelvic floor = 0.79 MPa; Lei et al. Int Urogynecol J Pelvic Floor Dysfunct. 18(6):603-7, 2007). Cells on PCL showed significantly greater cell viability than PP at day 7 (p < 0.0001). At D14 the composite scaffold showed significantly greater cell viability than PP (p = 0.0006). PCL was the best performing scaffold for soluble collagen production at day 14 (106.1 µg versus 13.04 µg for PP, p = 0.0173). CONCLUSIONS: We have designed a biodegradable PCL mesh and a composite mesh which demonstrate better biocompatibility than PP and mechanical properties closer to that of healthy pelvic floor tissue. This in vitro study provides promising evidence that these two implants should be evaluated in animal and human trials.

Peritoneal Submesothelial Stromal Cells Support Hematopoiesis and Differentiate into Osteogenic and Adipogenic Cell Lineages.

The peritoneum is a thin membrane that covers most of the abdominal organs, composed of a monolayer of mesothelial cells and subjacent submesothelial loose connective tissue. Cells from the peritoneal wall are correlated with peritoneal fibrosis and epithelial-to-mesenchymal transition. However, the distinct involvement of mesothelial or submesothelial cells in such phenomena is still not clear. Here, we propose a new strategy to obtain stromal cells from anterior peritoneal wall explant cultures. These cells migrated from peritoneal tissues and proliferated in vitro for 4 weeks as adherent fibroblast-like cells. Optical and electronic microscopy analyses of the fragments revealed a significant submesothelial disorganization. The obtained cells were characterized as cytokeratin- vimentin+ laminin+ α-smooth muscle actin+, suggesting a connective tissue origin. Moreover, at the third passage, these stromal cells were CD90+CD73+CD29+Flk-1+CD45-, a phenotype normally attributed to cells of mesenchymal origin. These cells were able to support hematopoiesis, expressing genes involved in myelopoiesis (SCF, G-CSF, GM-CSF, IL-7 and CXCL-12), and differentiated into osteogenic and adipogenic cell lineages. The methodology demonstrated in this work can be considered an excellent experimental model to understand the physiology of the peritoneal wall in healthy and pathological processes. Moreover, this work shows for the first time that submesothelial stromal cells have properties similar to those of mesenchymal cells from other origins.