QUANTIFICATION AND LOCALIZATION OF HYALURONAN IN A PTFE POLYMER IMPLANTED IN THE CORNEAL STROMA

The amount and distribution of hyaluronan in a PTFE polymer used to su pport an artificial cornea implanted in the rabbit cornea were determi ned. The findings were used to describe the polymer-corneal stroma int erface and the reason for the translucence and wettability of this ori ginally opaque and hydrophobic biomaterial. PTFE disks (6 mm in diamet er, 0.2 mm thick, 50 mu m in pore size) were implanted after a free-ha nd intralamellar dissection. The corneas were removed 15 days, 1 month , and 3 months after implantation. The hyaluronan content of pepsin-so lubilized corneal stromal extracts and its distribution (7 mu m cryost at sections) were investigated using an alkaline phosphatase-linked hy aluronectin assay that specifically detects nanogram amounts of hyalur onan. A PTFE polymer implant caused large, transient increases in hyal uronan density in the implanted stroma. The presence of amphiphilic hy aluronan in the polymer 15 days post implantation probably produced tr anslucence and wettability of this opaque, hydrophobic implant despite the absence of cells. The hyaluronan density in the PTFE polymer incr eased considerably during the first month and then decreased to stabil ize at a moderate level by the third month. These changes in hyalurona n density parallel the invasion of the polymer by inflammatory cells d uring the first month and the subsequent replacement of these cells by fibroblasts. The PTFE polymer is a good interface that is compatible with the native corneal stroma, and our results indicate that hyaluron an, because of its amphiphilic character, plays a major role in the po lymer wettability and translucence and in the production of typical co rneal extracellular matrix within the pores of the polymer. (C) 1998 J ohn Wiley & Sons, Inc.