Associations between measures of vascular structure and function and systemic circulating blood markers in humans.

Examination of relationships between systemic markers and functional measures of arterial structure and function may assist in determining alternative indices of vascular regulation and designing and evaluating interventions to improve arterial structure and function. Twenty young healthy individuals, 20 older healthy men, and 26 individuals with coronary artery disease (CAD), comprising a spectrum of vascular health, participated. Systemic markers of vascular structure and function included: pro-collagen type I C-peptide (PIP) - marker of collagen synthesis, C-telopeptide of type I collagen (CTX) - marker of collagen degradation, endothelin-1 (ET-1) - vasoconstrictor, and interleukin-6 (IL-6) - inflammatory marker. Functional measures of arterial structure and function included carotid artery distensibility and brachial artery flow-mediated dilation (FMD). Moderate positive relationships were observed between carotid distensibility and CTX and PIP (r = 0.57, P < 0.0001 and r = 0.47, P < 0.0001). A negative correlation exists between ET-1 and FMD (r = -0.44, P = 0.0004); however, no relationship was observed between IL-6 and FMD (P = 0.25). Over a broad range of vascular health, relationships were observed between markers of type I collagen turnover and arterial stiffness and between a marker of vasoconstriction and endothelial function. These results indicate that regulatory links, between the indices examined, exist. Therefore, monitoring systemic markers rather than functional vascular measures, may provide sufficient information about vascular health and should be considered in the design and evaluation of vascular interventions.