Effect of the urine conditioning film on ureteral stent encrustation and characterization of its protein composition

The goal of this study was to characterize the protein composition of the conditioning film deposited onto the surface of ureteral stents during in vivo implantation and to relate its presence to the precipitation of calcium crystals. The protein pattern of the conditioning film of implanted nonencrusted and encrusted urological stents was assessed by SDS-PAGE and Western blot of the desorbed species. The results obtained highlighted different electrophoresis profiles between nonencrusted and encrusted stents. Western blot showed the ubiquitous presence of albumin, while Tamm-Horsfall Protein and α1-microglobulin adsorption was limited to nonencrusted devices. By an in vitro dynamic model in which artificial urine was flowed through the lumen of control and retrieved nonencrusted stents, we demonstrated that the organic layer remarkably enhanced crystal precipitation and aggregation events on the surface.