Latent TGF beta binding protein-1 and fibrillin-1 in human capsular opacification and in cultured lens epithelial cells

Background/aim-It was previously reported that collagenous extracellular ma trix (ECM) in human capsular opacification contained isoforms of transformi ng growth factor beta (TGF beta). In the present study, the authors perform ed immunohistochemistry to examine whether ECM in human capsular opacificat ion and in cultures of bovine lens epithelial cells (LECs) contained latent TGF beta binding protein-1 (LTBP-1), TGF beta1 latency associated peptide (beta1-LAP), and fibrillin-1, a suspected ligand of LTBP-1 as well as a com ponent of the extracellular microfibrillar apparatus. The aim of the study was to further clarify the mechanism of TGF beta1 deposition in ECM of caps ular opacification. Methods-Human capsular opacification specimens and uninjured lens capsules, as well as cultured bovine LECs, were processed for immunohistochemistry u sing antibodies against LTBP-1, beta1-LAP, fibrillin-1, and collagen type I . Results-LTBP-1, beta1-LAP, and fibrillin-1 all were localised to the ECM in human capsular opacification. Uninjured lens epithelium stained for beta1- LAP, but not for LTBP-1 and fibrillin-1. ECM deposited in confluent LEC cul tures stained for LTBP-1, beta1-LAP, and fibrillin-1, while cultures with o nly sparse cellularity were unstained for LTBP-1 or fibrillin-1. Conclusions-LECs upregulate LTBP-1 and fibrillin-1 during postoperative hea ling. LTBP-1, beta1-LAP, and fibrillin-1 colocalised to the ECM in capsular opacification and in confluent LEC cultures. TGF beta1 is considered to de posit in ECM in the large latent form. ECM secreted by LEC may function as a scavenger or repository of TGF beta.