ObjectiveNeuropeptide Y (NPY), a sympathetic cotransmitter, has been shown to promote angiogenesis in in-vitro models. The aim of this study was to evaluate the relationship of plasma NPY levels with coronary collateral vessel development in patients with coronary artery disease.MethodsThe study included 81 patients with at least one coronary stenosis with at least 80% narrowing in coronary angiography. Collateral vessels were graded according to the Rentrop classification. The study patients were divided into two groups, namely patients with well-developed collaterals and patients with poorly developed collaterals. Well-developed collaterals were defined as Rentrop collateral score of at least 2. Plasma levels of NPY, vascular endothelial growth factor, fibroblast growth factor, and noradrenaline were measured using an enzyme-linked immunosorbent assay.ResultsPlasma NPY was significantly higher in patients with well-developed collaterals as compared with patients with poorly developed collaterals (P=0.026). In contrast, plasma noradrenaline was significantly lower in patients with well-developed collaterals (P=0.022). There was no statistically significant difference in vascular endothelial growth factor and fibroblast growth factor levels between groups. The NPY level was positively correlated with the presence of diabetes (r=0.528, P<0.001). The extent of coronary artery disease (Gensini score) was significantly higher in patients with well-developed collaterals (P<0.001). After confounding variables were controlled for, the NPY level in patients with well-developed collaterals was significantly higher than those patients with poorly developed collaterals.ConclusionIn this study, NPY levels were found to be significantly higher in patients with well-developed coronary collaterals compared with patients with poorly developed collaterals. New studies are needed to show whether this relationship is causal. (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.