Abstract
Purpose: :
Connective tissue growth factor (CTGF) has been indicated to induce cell growth and the production and deposition of extracellular matrix. The localization of CTGF was identified in proliferative vitreoretinopathy membranes and other intraocular fibrous membranes by immunohistochemical study. However, its critical effects and roles in vitreoretinal diseases remain to be clarified. We investigated the association of CTGF with proliferative eye diseases both in vitro and in vivo.
Methods: :
Hyalocytes, retinal pigment epithelial cells (RPEs) and retinal capillary endothelial cells (RECs) were isolated from bovine eyes. CTGF gene expression by those three kinds of cells was examined by Northern blot analysis. Besides, the cells were stimulated with CTGF and then total cell lysates were isolated to analyze the phosphorylation state of p44/42 MAPK by Western blot analysis. The effect of CTGF on thymidine uptake by each kind of cells was also examined to evaluate the growth activity. In addition, vitreous samples were collected from patients who underwent pars plana vitrectomy due to various eye diseases, and the concentrations of CTGF in the vitreous were measured by enzyme–linked immunosorbent assay.
Results: :
Each kind of cultured cells expressed CTGF gene. While CTGF caused significant induction of the phosphorylation state of p44/42 MAPK and thymidine uptake by hyalocytes and RPEs, CTGF showed no obvious effect on RECs. The concentrations of CTGF in the vitreous from patients with proliferative eye diseases (proliferative diabetic retinopathy and proliferative vitreoretinopathy) were significantly higher than those from patients with non–proliferative eye diseases (macular hole and rhegmatogenous retinal detachment).
Conclusions: :
It is suggested that CTGF, whose expression is elevated in proliferative eye diseases, might play a role in the pathogenesis of proliferative eye diseases via the formation of fibrous proliferative membrane without inducing angiogenesis.
Keywords: proliferative vitreoretinopathy • extracellular matrix • vitreous