*4.4.1.4 Basic fibroblast growth factor*

Amongst the factors which play a role in mitogen and antigenic activity involving survival and maturation of glial cells and neuron, basic fibroblast growth factor (bFGF) play an important role [50]. Neurotrophic factors synthesised from glial cell line stimulates Muller cells which produce bFGF, which initiates endothelial cell proliferation and VEGF production [51, 52]. Studies have detected presence of two growth factors in same cells of ocular neovascular membrane suggesting more than one growth factor may contribute to defective angiogenesis. Growth factors are not exclusively seen in neovascular tissues and are not localised mainly in the vascular endothelium as shown by this study which detected their presence in choroidal neovascular membranes also [53]. Another study documented increased levels of basic fibroblast growth factor in vitreous specimens from patients with proliferative diabetic retinopathy, particularly those with active proliferative retinopathy [54]. Various studies have shown that bFGF, nerve growth factor, and glial cell linederived neurotrophic factor are also part of process involved in the formation of epiretinal membranes in PDR [55]. This confirms that both vegf and basic fibroblast growth factor are present in diabetic eyes and part of process causing PDR.
