Octreotide inhibits growth factor-induced bovine choriocapillary endothelial cells in vitro.

Abstract

Response to growth factors by the choriocapillaris is one of the main aspects in the development and progression of choroidal neovascularization in age-related macular degeneration (AMD). The aim of the study was to examine the effect of octreotide--an analogue of somatostatin with possible favorable effects in the treatment of age-related macular degeneration--on growth factor-activated bovine choriocapillary endothelial cells (BCEC). Cultivated BCEC were stimulated with 20 ng/ml VEGF, 5 ng/ml bFGF, 50 ng/ml TGFbeta(2), or 50 ng/ml IGF-I for 24 h. Afterwards, the cells were incubated for a further 24 h with octreotide (10(-6) M). BCEC proliferation was determined by [(3)H]-thymidine incorporation. The experiments were performed in normal conditions and in O(2)-limited (5% O(2)) atmosphere. VEGF, bFGF, and IGF-I significantly stimulated BCEC proliferation under normoxic as well as under hypoxic conditions ( P<0.05); the value for TGFbeta(2)stimulation was not significant. Under normoxic conditions, after addition of octreotide to VEGF-, bFGF-, and IGF-I-stimulated cells there was no longer any significant [(3)H]-thymidine incorporation compared to the control medium. Under hypoxic conditions similar results were obtained after addition of octreotide to VEGF-, bFGF-, and IGF-I-stimulated cells. Octreotide has inhibitory properties after activation of BCEC with growth factors under normoxic and hypoxic conditions in vitro. Since activation of these cells is a crucial event in the development and progression of AMD, octreotide may be a potential drug for treatment of choroidal neovascularization in these patients.