CD31+ T cells, endothelial function and cardiovascular risk.

Deficits in endothelial cell repair mechanisms are thought to contribute to the aetiology of endothelial dysfunction and, subsequently, cardiovascular disease (CVD). CD31(+) T cells or so-called "angiogenic T cells" are a newly defined T cell subset that exhibit favourable vascular qualities and show a strong negative relation with atherosclerotic disease severity. Despite growing evidence that CD31(+) T cells are important for vascular homeostasis, it is currently unknown if CD31(+) T cell number and function are related to endothelial function and CVD risk in healthy adults. To address this question, we studied 24 healthy adult men (ages: 21-70). Endothelial function was assessed by the forearm blood flow (FBF) response to intra-arterial infusion of acetylcholine (ACh) and CVD risk was estimated by Framingham Risk Score (FRS). CD31(+) T cell number was determined by fluorescence-activated cell sorting. Magnetic-activated cell sorting was used to isolate CD31(+) T cells for Boyden chamber migration. No relation was observed between CD31(+) T cell number and FBF response to ACh or FRS. However, CD31(+) T cell migration to stromal cell-derived factor (SDF)-1α and vascular endothelial growth factor (VEGF) was positively correlated with FBF response to ACh (r = 0.43 for SDF-1α; r = 0.38 for VEGF; both P<0.05) and inversely related to FRS (r = -0.53 for SDF-1α; r = -0.48 for VEGF; both P<0.05). These findings demonstrate that CD31(+) T cell function, but not number, is associated with in vivo endothelial function and CVD risk in healthy adult men.