Exercise testing increases the endothelial turnover : possible role of systolic blood pressure

Objectives: We studied whether a single bout of acute physical exercise has effects on the endothelial compartment, causing a rise in the number of endothelial progenitor cells (EPC) and circulating endothelial cells (CEC) in healthy subjects. Methods: 12 healthy non-smoker volunteers performed a maximal exercise stress test. Clinical parameters have been measured, venous blood samples have been drawn right before and after the exercise, and we have measured the number of CEC and EPC using flow cytometry and the level of cardiac troponin I (cTnI) using ELISA. CEC have been immunophenotipically identified as cells expressing on their membrane the CD31 and CD146 antigens, and CEP have been characterised by their expression of the CD34, KDR and/or CD133 antigens. Results: CEC rise fast and significantly after physical exercise and their rise, as well as their absolute variation, correlate with the systolic arterial pressure measured at the maximal exercise level. It hasn't been possible to show, under these experimental conditions, a significant variation of the CEP and CTnI with exercise. Conclusions: Acute physical exercise cause a prompt rise in the number of CEC and this rise correlate with the peak of systolic blood pressure. We can therefore hypothesise that the mechanical stimulus (pressure) can accelerate the normal turnover of endothelial cells. It is possible that the missed observation of a rise in the EPC could depend on the brief time interval between exercise and blood drawn. Only further studies can clarify this matter and establish if physical exercise can represent a simple method to mobilise these cells, exploitable in the field of regenerative medicine.