A long-term fish diet modifies the toxic properties of human partially oxidized LDL on vascular preparations in vitro

Both LDL oxidation and LDL fatty acid composition affect vascular relaxatio n and contraction. The aim of this study was to investigate whether long-la sting dietary habits (vegetarian, fish and high saturated fat as a control group) can change those properties of partially oxidized LDL (ox-LDL) which are reflected in altered vascular responses measured with a bioassay. The effects of ox-LDL were investigated on rat mesenteric arteries. In endothelium intact arterial rings the contractile responses to noradrena line (NA) tended to be diminished in the presence of ox-LDL derived from th e fish diet group compared with the other groups. In the endothelium denude d arterial rings the contractile responses to NA and KCl were significantly enhanced by ox-LDL from the fish diet group compared with the control grou p. The ox-LDL from the fish diet group increased the diclofenac, L-NAME res istant relaxations to ACh compared to the control diet group suggesting the role of endothelium derived hyperpolarizing factor (EDHF). In conclusion, partially oxidized LDL from subjects living on a fish diet i s biologically more vasoactive in bioassay systems than partially oxidized LDL from those living on vegetarian or saturated fatty acid containing diet s. The impaired responses in vasoconstriction and improved vasodilation see m to be endothelium dependent.