The effects of growth factors and antiproliferative agents on ocular fibroblasts and wound healing after glaucoma filtration surgery

Glaucoma (visual damage associated with raised intraocular pressure) is a major cause of worldwide blindness. The most effective treatment for glaucoma is filtration surgery, but the major cause of failure and suboptimal lowering of the intraocular pressure is scarring at the site of the surgery. In this thesis, I investigated the role of stimulatory molecules found in aqueous humour, and the effects of antiproliferative agents on ocular fibroblasts. Fibronectin levels were found to be significantly raised in the aqueous of patients with glaucoma, but the chemoattractant activity of the aqueous was not. All growth factors tested stimulated proliferation, migration and collagen production, but transforming growth factor-β1 stimulated proliferation, migration and proline uptake at much lower concentrations than the other growth factors (epidermal, basic fibroblast and insulin-like growth factor-1). Following treatments with antiproliferative agents ocular fibroblasts could be growth arrested for periods much longer than previously thought, suggesting that single short treatments with these agents would inhibit fibroblast proliferation in the long term. The animal model results confirmed the in vitro findings with 5 minute applications of antiproliferative agents. Long term titratable effects on wound healing were shown in an experimental model of wound healing after glaucoma filtration surgery. The effects were focal and confined to the treated areas. Cells growth arrested by treatment could still be stimulated to increase RNA levels after stimulation with TGF-β1. The experiments in this thesis have shown that growth factors present in the aqueous can have profound effects on the proliferation, migration and collagen production of ocular fibroblasts. In addition, the studies have led to a new understanding of the long term effects of short exposures to antiproliferative agents in vitro and in vivo, particularly that long term growth arrest can be induced and this effect can be localised, and can be varied to some degree. Finally, fibroblasts can still respond to growth factors despite being growth arrested