[Increased expression of endothelin-1-- a novel diagnostic marker for early AMD detection?]

The relationship between ischemic vascular disease and age-related macular degeneration may indicate the role of vascular injury as the primary insult causing functional deficits in age-related macular degeneration. The vasoactive factors produced by endothelial cells include endothelin-1 (ET-1), which is one of the most potent vasoconstricting peptides. In this study we sought to explore the potential role of endothelial dysfunction in the pathogenesis of age-related macular degeneration by measuring the concentration of ET-1 in peripheral blood of individuals diagnosed with age-related macular degeneration and evaluating its intracellular expression in peripheral blood cells, on mRNA level.

Peripheral blood samples from 31 patients with diagnosed dry age-related macular degeneration and 46 patients with neovascular age-related macular degeneration were collected. Forty six age- and sex-matched volunteers without age-related macular degeneration were enrolled as a control group. ET-1 plasma levels were analyzed by ELISA and intracellular expression of ET-1 in peripheral blood cells was studied by using qRT-PCR.

The expression of intracellular ET-1 was significantly elevated in peripheral blood cells of both dry and wet age-related macular degeneration patients compared with the control subjects. Immunofluorescence staining revealed that ET-1 was specifically expressed in the circulating endothelial cells.

We assume that damaged endothelial cells may release a variety of vasoconstricting molecules, including ET-1, leading to derangement between the endothelium-derived relaxing and contracting factors. Local retinal ischemia consequently develops which may promote the development of retinal degeneration in patients with age-related macular degeneration,