Mechanism underlying vascular remodeling in relation to circulating CD34-positive cells among older Japanese men

Development of structural atherosclerosis, an established cardiovascular risk factor, requires hematopoietic stem cells known as CD34-positive cells. However, an inverse association between circulating CD34-positive cell count and cardiovascular disease has been reported. These studies evoke a contradiction: characteristics associated with a low risk of developing structural atherosclerosis are also associated with a high risk of cardiovascular disease. To clarify the mechanisms underlying vascular remodeling, we conducted several epidemiological studies of Japanese men aged 60 to 69 years who participated in annual health check-ups. The present study summarizes those epidemiological studies and adds some discussion. From the perspective of endothelial repair activity, there are significant differences between functional versus structural atherosclerosis. Aggressive endothelial repair increases both functional and structural atherosclerosis. Deficient endothelial repair related to a shortage of CD34-positive cells due to consumption furthers functional atherosclerosis but not structural atherosclerosis. Therefore, the lack of structural atherosclerosis does not always reflect a favorable condition for the endothelium. Although further investigation is necessary, the present study suggests that higher endothelial repair activity that leads to structural atherosclerosis might have a beneficial effect on vascular health among older men.