OXIDIZED LIPOPROTEIN(A) INHIBITS ENDOTHELIUM-DEPENDENT DILATION - PREVENTION BY HIGH-DENSITY-LIPOPROTEIN

We assessed the effects of human native and oxidized lipoprotein(a) (1 50 min, 30 and 100 mu g/ml) on endothelium-dependent vasodilation of i solated rabbit renal arteries. Vasodilation was not attenuated after i ncubation of arteries with native lipoprotein(a). However, when the ar teries were exposed to oxidized lipoprotein(a), acetylcholine-induced vasodilation was dose dependently significantly impaired. Concomitant incubation of segments with high density lipoprotein (HDL, 0.5 mg/ml) prevented the attenuation of dilations induced by oxidized lipoprotein (a). Thus, we report for the first time that oxidized lipoprotein(a) i mpairs endothelium-dependent vasodilation, and that HDL prevents its i nhibitory effect.