In vitro biocompatibility evaluation of naturally derived and synthetic biomaterials using normal human bladder smooth muscle cells.

PURPOSE: Tissue engineering of the urinary tract often requires the use of various biomaterials. Adequate biomaterial biocompatibility is necessary for successful urinary reconstruction. In this study using a primary normal human bladder smooth muscle cell culture system we evaluated the in vitro biocompatibility of a number of naturally derived biomaterials, including bladder submucosa, small intestinal submucosa, collagen and alginate, and polymeric biomaterials, including polyglycolic acid, poly(L-lactic acid) and poly(lactic-co-glycolic acid, which have been used for urinary reconstruction experimentally or clinically.
MATERIALS AND METHODS: To determine the cytotoxic and bioactive effects of bladder submucosa, small intestinal submucosa, collagen, alginate, polyglycolic acid, poly(L-lactic acid) and poly(lactic-co-glycolic acid) we measured cell viability, metabolic activity, apoptotic properties and DNA synthesis activity with 4 types of assays, namely Neutral Red (Sigma Chemical Co., St. Louis, Missouri), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (Sigma Chemical Co.), apoptotic activity and tritiated thymidine incorporation (Dupont NEN, Boston, Massachusetts) assays. Normal human bladder smooth muscle cells were cultured with the extracts of the biomaterials or cultured in direct contact with the biomaterials.
RESULTS: All naturally derived and synthetic biomaterials tested in this study except alginate exhibited nontoxic and bioactive effects on human bladder smooth muscle cells (HBSMCs) in vitro, as indicated by the 4 types of biocompatibility assays using the extract and direct contact methods. Cell viability, apoptotic properties, metabolic activity and DNA synthesis activity of HBSMCs cultured with the extracts of the biomaterials or cultured in direct contact with the biomaterials were not significantly different from those of negative controls (fresh medium with no extracts or tissue culture plates without biomaterials).
CONCLUSIONS: All naturally derived and synthetic biomaterials tested in this study except alginate exhibited nontoxic and bioactive effects on HBSMCs in vitro. This normal primary human bladder smooth muscle cell culture model is suitable for in vitro biocompatibility assessment. It provides information on cell-biomaterial interactions and on the ability of biomaterials to support bioactive cell functions.