Transforming growth factor-beta(1) induces alpha-smooth muscle actin expression and fibronectin synthesis in cultured human retinal pigment epithelial cells

Background: Proliferative vitreoretinopathy is a serious complication of re tinal detachment, yet its pathogenesis is not fully understood. Retinal pig ment epithelial cells and glial cells are found in the fibrous membranes in proliferative vitreoretinopathy. Many cytokines are involved in the pathol ogy. Transforming growth factor (TGF)-beta (1), a cytokine found in serum, has been shown to be an important factor regulating the synthesis of fibrou s extracellular matrix in proliferative vitreoretinopathy. Methods: Cultured human retinal pigment epithelial cells were used in the e xperiments. The effects of TGF-beta (1) on phenotype and function in retina l pigment epithelial cells were recorded as changes in the expression of al pha -smooth muscle actin and fibronectin synthesis using immunohistochemist ry and enzyme-linked immunosorbent assay, respectively. Results: TGF-beta (1) induced the expression of alpha -smooth muscle actin (P < 0.0001, n = 3), and significantly increased the synthesis of fibronect in by cultured human retinal pigment epithelial cells (P < 0.01, n = 4). Conclusions: Elevated levels of TGF-beta (1) in proliferative vitreoretinop athy may contribute to phenotype changes in retinal pigment epithelial cell s leading to matrix deposition and contraction. Since the elevated levels o f TGF-beta (1) may emanate from a number of diverse sources in proliferativ e vitreoretinopathy, developing an antagonist to TGF-beta (1) may offer an approach to the treatment of proliferative vitreoretinopathy.