Vitamin E but not 17beta-estradiol protects against vascular toxicity induced by beta-amyloid wild type and the Dutch amyloid variant.

Amyloid beta-peptide (Abeta) fibril deposition on cerebral vessels produces cerebral amyloid angiopathy that appears in the majority of Alzheimer's disease patients. An early onset of a cerebral amyloid angiopathy variant called hereditary cerebral hemorrhage with amyloidosis of the Dutch type is caused by a point mutation in Abeta yielding Abeta(Glu22-->Gln). The present study addresses the effect of amyloid fibrils from both wild-type and mutated Abeta on vascular cells, as well as the putative protective role of antioxidants on amyloid angiopathy. For this purpose, we studied the cytotoxicity induced by Abeta(1-40 Glu22-->Gln) and Abeta(1-40 wild-type) fibrils on human venule endothelial cells and rat aorta smooth muscle cells. We observed that Abeta(Glu22-->Gln) fibrils are more toxic for vascular cells than the wild-type fibrils. We also evaluated the cytotoxicity of Abeta fibrils bound with acetylcholinesterase (AChE), a common component of amyloid deposits. Abeta(1-40 wild-type)-AChE fibrillar complexes, similar to neuronal cells, resulted in an increased toxicity on vascular cells. Previous reports showing that antioxidants are able to reduce the toxicity of Abeta fibrils on neuronal cells prompted us to test the effect of vitamin E, vitamin C, and 17beta-estradiol on vascular damage induced by Abeta(wild-type) and Abeta(Glu22-->Gln). Our data indicate that vitamin E attenuated significantly the Abeta-mediated cytotoxicity on vascular cells, although 17beta-estradiol and vitamin C failed to inhibit the cytotoxicity induced by Abeta fibrils.