Remnant-like particles from subjects who died of coronary artery disease suppress NO synthase activity and attenuate endothelium-dependent vasorelaxation.

Background: Plasma levels of remnant-like particles (RLP) is one of the predictive markers for coronary artery disease (CAD), and the inhibition by RLP of endothelium-dependent vasorelaxation has been reported. We attempted to clarify whether or not RLP, which inhibits endothelium-dependent vasorelaxation, affects nitric oxide (NO) production and NO synthase (eNOS) levels in cultured endothelial cells.

Methods: RLP were obtained from postmortem blood of subjects who died of CAD. Modification by RLP of acetylcholine-induced relaxation of rabbit aorta, and changes in NO production and (eNOS) in cultured bovine endothelial cells were examined.

Results: RLP at 750 and 1500 microg triglyceride/ml inhibited vasorelaxation, and at 5-160 microg triglyceride/ml, concentration-dependently inhibited NO production. However, (eNOS) did not decrease after incubation with RLP.

Conclusion: Postmortem RLP from subjects who died of CAD do not change the amount of (eNOS), but rather, inhibits its activity and attenuates endothelium-dependent vasorelaxation.