Circulating progenitor cells and cardiovascular outcomes: Latest evidence on angiotensin-converting enzyme inhibitors

Abstract

The ability of organisms spontaneously to develop collateral vessels is an important response to vascular occlusions and restores perfusion of ischaemic tissues. Pathological conditions such as hyperlipidaemia, diabetes, and hypertension lead to endothelial dysfunction, impairment of neovascularization, and insufficient tissue perfusion. Thus, in most degenerative cardiovascular diseases, these natural adaptive responses to a compromised perfusion are insufficient to block the progression of the disease and ischaemic complications. Circulating endothelial progenitor cells (EPCs) play a role in the repair of damage to blood vessels under ischaemic conditions. To date, EPC numbers have been inversely correlated with the number of cardiovascular risk factors, extent of coronary disease, and future cardiovascular events. Interestingly, hypertension is associated with a decrease in the number of circulating EPCs parallel to the increase in cardiovascular risk score. Treatments with perindopril [angiotensin-converting enzyme (ACE) inhibitor] and losartan [angiotensin receptor blocker (ARB)] both improved blood flow recovery in a model of hind limb ischaemia in spontaneously hypertensive rats. Perindopril but not losartan increased the number of circulating EPCs. Although the decrease in blood pressure is similar with ACE inhibitors and ARBs, normalization of the number of circulating EPCs by ACE inhibitors could account for the differential benefits observed for organ protection, especially for myocardial infarction protection. © The Author 2009.