BACKGROUND:

Currently, the predominant hypothesis regarding atherosclerosis is that it is in major part driven by two independent pathways: hyperlipidemia (the "stimulation") and inflammation (the "response"). Although vascular cells mediate the influence of inflammation on atherosclerosis, very little is known about vascular cell epidemiology and the relationship of vascular cell phenotypes to atherosclerosis. The main hypothesis tested in this study is that variation in vascular cell biology is related to the population variation in atherosclerosis.

DESIGN NARRATIVE:

The cross-sectional study will be nested within a large cohort study, the Multiethnic Study of Atherosclerosis (MESA). A partial sample of 1,000 individuals who have undergone other special laboratory analyses will be identified and new measures collected as part of their upcoming site visit. A number of novel cellular phenotypes describing the innate immune response (monocyte activation, natural killer and T cell counts), the adaptive immune response (TH1 and TH2 helper cells, and memory T cells), and vessel integrity (circulating endothelial progenitor cells) will be measured in these participants. Plasma constituents will also be measured that relate to the cellular phenotypes. The overall goal is to test the hypothesis that these novel phenotypes are associated with subclinical atherosclerosis in the coronary and carotid arteries assessed by quantification of coronary calcification (CAC) and B-mode ultrasound (CIMT), in addition to the other subclinical measures available from the MESA cohort.