Transforming growth factor beta2 in the vitreous in proliferative diabetic retinopathy.

OBJECTIVE To evaluate the hypothesis that transforming growth factor beta2 (TGF-beta2) is involved in the cause of proliferative diabetic retinopathy (PDR). METHODS We assayed TGF-beta2 levels in the vitreous of patients with PDR and other vitreoretinal disorders. Forty-nine vitreous specimens were obtained from eyes of patients with PDR undergoing vitrectomy, and 19 vitreous specimens from nondiabetic subjects served as controls. We assessed TGF-beta2 levels using an enzyme-linked immunosorbent assay. Both mature and total TGF-beta2 levels were quantified. RESULTS The mean (+/- SD) total levels of TGF-beta2 were 2634 (+/- 1652) pg/mL in the patients with PDR and 1305 (+/- 972) pg/mL in controls. The mean (+/- SD) levels of mature TGF-beta2 were 244 (+/- 316) pg/mL in patients with PDR and 79 (+/- 81) pg/mL in controls. Total and mature TGF-beta2 levels were significantly greater in patients with PDR (total TGF-beta2, P <.001; mature TGF-beta2, P <.01). Mature TGF-beta2 levels were higher in the vitreous of patients who had severe fibrous proliferation. CONCLUSION The results indicate increased levels of both total and mature TGF-beta2 in the vitreous of patients with PDR, suggesting that TGF-beta2 plays an important role in the pathogenesis of PDR.