Hyalocyte proliferation and ECM accumulation modulated by bFGF and TGF-beta1.

Purpose: In cases of severe retinal diseases, the vitreous body has to be removed and replaced by a suitable biomaterial. Currently, however, no satisfying long-term vitreous substitute is in clinical use. A novel therapeutic concept represents the combination of hyalocytes with suitable biomaterials. The goal of the present study was to evaluate the potential of bFGF and TGF-beta1 as tools to control hyalocyte proliferation and the accumulation of extracellular matrix (ECM).

Methods: In vitro investigation on the influence of different concentrations of bFGF and TGF-beta1 on hyalocyte morphology, proliferation and ECM production.

Results: Both growth factors affected hyalocyte morphology; small, round cells could be observed after bFGF supplementation, whereas the cells appeared more completely spread when cultured with TGF-beta1. Hyalocyte proliferation was increased 3-fold by 10 ng/ml bFGF; 1 ng/ml TGF-beta1 in contrast reduced cell proliferation to about 40% of the control. Converse effects of the growth factors could also be observed on the ECM accumulation of hyalocytes; whereas bFGF halved ECM accumulation, TGF-beta1 enhanced the ECM production up to 3-fold. Precultivation of hyalocytes with bFGF for two passages had no influence on their subsequent accumulation of glycosaminoglycans (GAG). However, cells precultivated with bFGF exhibited a doubled accumulation of collagen compared to controls.

Conclusions: The observed opposite effects of bFGF and TGF-beta1 on hyalocyte proliferation and ECM accumulation may allow for the control of hyaloycte properties. Therefore, these two growth factors seem to be valuable tools towards the development of a cell-based vitreous substitute.