LDL increases (CA++)i in human endothelial cells and augments thrombin-induced cell signalling.

Low-density lipoproteins (LDLs) stimulate cytosolic calcium ([Ca ++ ] i ) in endothelial cells. To elucidate the mechanisms of this response, we compared the effects of low-density lipoprotein (LDL) with those of thrombin, a known endothelial cell agonist. [Ca ++ ], was measured in cultured endothelial cells from human umbilical veins. Both spectrofluorometry of single cells with fura-2 and confocal microscopy were used. LDL (100 μg/ml) led to a rapid increase in [Ca ++ ], (143±46 nmol/L to 426±69 nmd/L; p<0.05) followed by a sustained plateau phase