BETA-IG-H3 IS SYNTHESIZED BY CORNEAL EPITHELIUM AND PERHAPS ENDOTHELIUM IN FUCHS DYSTROPHIC CORNEAS

Purpose. Deposition of abnormal sub-epithelial matrix and posterior co llagenous layer by epithelium and endothelium, respectively, in Fuchs' dystrophy gives us the opportunity to determine if these tissues synt hesize beta ig-h3. Methods. Immunohisto-/immunocytochemistry of cornea s were conducted with rabbit anti-human beta ig-h3 and monoclonal anti human type VI collagen. Labeled sense and anti-sense beta ig-h3 oligon ucleotide probes were used for in situ hybridization. Results. beta ig -h3-specific fluorescence was found just beneath detached epithelium i n the sub-epithelial matrix, abnormal Descemet's membrane and posterio r collagenous layer. Type VI collagen co-localized with beta ig-h3 wit hin abnormal sub-epithelial matrix and corneal stroma adjacent to Desc emet's membrane. beta ig-h3 mRNA was detected in corneal epithelium of dystrophic corneas. Conclusions. Expression of beta ig-h3 in sub-epit helial matrix and posterior collagenous layer of Fuchs' dystrophy is c onsistent with the synthesis of new extracellular matrices by epitheli al and endothelial tissues. beta ig-h3 mRNA in corneal epithelium furt her supports an epithelial source of this protein. Endothelial synthes is of beta ig-h3 is based on circumstantial evidence due to cell loss during surgical and histological procedures. Go-localization of beta i g-h3 with type VI collagen in abnormal sub-epithelial matrix and at th e stromal/Descemet's membrane interface suggest this collagen in assoc iation with beta ig-h3 interacts with these tissues and anchors them t o the adjacent stroma.