Accumulation of latent transforming growth factor-beta binding protein-1 and TGF beta 1 in extracellular matrix of filtering bleb and of cultured human subconjunctival fibroblasts

Purpose: To examine immunohistochemically whether extracellular matrix (ECM ) of the filtering bleb and of cultured human subconjunctival fibroblasts c ontains latent TGF beta binding protein-1 (LTBP-1) and TGF beta. Methods: A n enucleated human eye that had undergone trabeculectomy and cultured human subconjunctival fibroblasts were processed for light microscopic immunohis tochemistry. Antibodies against LTBP-1, collagen types, fibrillin-1 and TGF betas were used. TGF beta1 was located by detecting pi-latency associated peptide (LAP). Results: LTBP-1, beta1-LAP and fibrillin-1 were all located in the subepithelial ECM as well as in the basal epithelial cells of the co njunctiva over the filtering bleb. TGF beta2 and beta3 were immunolocated t o epithelium and/or fibroblasts/keratocytes. ECM deposited in confluent fib roblast cultures was positive for beta1-LAP, LTBP-1 and fibrillin-1, wherea s sparse cells were negative. Conclusions: LTBP-1, beta1-LAP and fibrillin- 1 are co-localized to the ECM of the filtering bleb and of cultured conjunc tival fibroblasts. Both conjunctival epithelium and fibroblasts are conside red to be the source of TGF beta in healing bleb. ECM secreted by in vivo a nd in vitro subconjunctival fibroblasts may works as a scavenger or reposit ory of TGF beta.