Posterior capsule opacification : An experimental study in vitro and in vivo

Abstract: The clinical and economic significance of posterior capsule opacification (PCO) makes it an important public health problem. A better understanding of the pathogenesis in order to reduce/prevent PCO is needed. For this purpose an experimental model in the rabbit was used and further developed in thisthesis. The model involves experimental cataract surgery and analysis of aqueous humor (AqH) inflammatory cells and mediators as well as growth factors and analysis of the after cataract weight, cell content and extracellular matrix content. Further, rabbit lens epithelial cells (LECs) were isolated andcultured in vitro. Using these cells the activity of proliferative factors in AqH after cataract surgery was analyzed at different time points after anti-inflammatory treatment and after the use of different surgical techniques. The same components that are reported to exist in human PCO, e.g. inflammation,cell proliferation, fibrosis and extracellular matrix production, have in this thesis also been shown to be components of PCO in the rabbit.No effect of anti-inflammatory treatments was observed on either AqH proliferative effect or after-cataract development despite a reduction in the early postoperative inflammatory response, as measured by AqH leukocytes, prostaglandin E2 (PGE2) and protein leakage. The AqH LEC proliferativeactivity as well as the AqH concentration of basic fibroblast growth factor (bFGF) increased after cataract surgery and the inhibitory transforming growth factor-β (TGF-β) decreased. Further, it was shown that both the early inflammatory response and LEC proliferation are to a great extent caused by the incision in the cornea during cataract surgery and no differences were found between the two surgical techniques, extracapsular cataract extraction and phacoemulsification.It is concluded that the rabbit model reflects human PCO development and is relevant for studying the pathogenesis of this postoperative complication. Furthermore, it is strongly suggested that reduction of the early postoperative inflammatory response does not reduce the development of PCO.Rather the corneal wound healing process and/or the release of growth factors seem to be important for this postoperative complication.