ABSTRACT
Pigment epithelium-derived factor (PEDF ) was originally found fromretinal pigment epithelium. It is confirmed that it plays an anti-angiogenic and apoptosis role in diabetic microangiopathy. Recently ,PEDF has been found to have a close relationship with insulin resistance ,type 2 diabetes and diabetic macroangiopathy. But the mechanism is unclear. More and more researches focused on its role in oxidative stress. PEDF may become a new target for diabetes and diabetic complication treatment and also a predictive factor for the disease.
ABSTRACT
BACKGROUND: Previous reports have described a decrease in retinal temperature and clinical improvement of wet age-related macular degeneration (AMD) after vitrectomy. We hypothesized that the retinal temperature decrease after vitrectomy plays a part in the suppression of wet AMD development. To test this hypothesis, we evaluated the temperature dependence of the expression of vascular endothelial growth factor-A (VEGF-A) and in vitro angiogen-esis in retinal pigment epithelium (RPE). RESULTS: We cultured ARPE-19 cells at 37, 35, 33 and 31°C and measured the expression of VEGF-A, VEGF-A splicing variants, and pigment epithelium-derived factor (PEDF). We performed an in vitro tube formation assay. The dehydrogenase activity was also evaluated at each temperature. Expression of VEGF-A significantly decreased with decreased temperature while PEDF expression did not. VEGF165 expression and in vitro angiogenesis also were temperature dependent. The dehydrogenase activity significantly decreased as the culture temperature decreased. CONCLUSIONS: RPE cultured under hypothermia that decreased cellular metabolism also had decreased VEGF-A and sustained PEDF expression, creating an anti-angiogenic environment. This mechanism may be associated with a beneficial effect after vitrectomy in patients with wet AMD.