Increase of Circulating Endothelial Progenitor Cells in Patients with Coronary Artery Disease After Exercise-Induced Ischemia

Abstract

Objectives— The concept of neovascularization in response to tissue ischemia has been extended by the finding of postnatal vasculogenesis initiated by endothelial progenitor cells (EPCs). The aim of this study was to analyze whether a maximal stress test in patients with coronary artery disease (CAD) increases the number of circulating EPCs. Methods and Results— Blood concentration of EPCs was analyzed by FACS and cell culture assay in CAD patients with (n=16) or without (n=12) exercise-induced myocardial ischemia and in healthy subjects (n=11) for up to 144 hours after maximal stress test. Plasma concentrations of vascular endothelial growth factor (VEGF), basic fibroblast growth factor, tumor necrosis factor-α, and granulocyte macrophage-colony stimulating factor were determined by ELISA. EPCs increased significantly in ischemic patients, with a maximum after 24 to 48 hours (cell culture: 3.3±0.5-fold increase; FACS: 3.1±0.6-fold increase) and returned to baseline within 72 hour. In nonischemic patients and healthy subjects, no EPC increase was detectable. VEGF levels in ischemic patients increased significantly after 2 to 6 hours (maximum after 2 hours; 4.0±1.1-fold increase) and no change was observed in nonischemic patients and healthy subjects; ΔVEGF and ΔEPC correlated significantly ( r =0.66). Conclusions— Patients with symptomatic CAD respond to a single episode of exercise-induced myocardial ischemia with a time-dependent increase in circulating EPCs. This increase may be related to and preceded by an increase in plasma VEGF.

Physical Activity in the Prevention and Treatment of Coronary Artery Disease

“…An elevated apoptotic rate of mature vascular endothelial cells in conjunction with an impaired regenerative capacity of CPC might further aggravate vascular alterations 55, 59, 60. Current knowledge of endothelial dysfunction in vascular disease is discussed in detail by Vanhoutte et al 61…”

Endothelial progenitor cells: Implications for cardiovascular disease

“…What are proper negative controls to set the gate for cell quantification? Several different negative controls are currently used in the different studies, ranging from isotype specific antibodies labeled with the same colors as the specific antibodies (8)(9)(10), addition of no antibodies at all to see the autofluorescence of the cells, to the fluorescence minus one (FMO) strategy [reviewed in (11)]. Another factor complicating the characterization of EPCs is the fact that the expression of the often used stem cell marker CD34 is not only restricted to stem cells, but is also expressed on mature microvascular endothelial cells (12,13).…”

“…After the isolation, the cells are plated on cell culture dishes coated with either fibronectin (19)(20)(21) or gelatin (8,9,22). Already these variations in the coating strategy may have an influence on the results obtained by cell culture with respect to cell number, cell phenotype, and cell function.…”

“…''Early'' EPCs appear within 4-7 days of culture, are spindle-shaped, and express both endothelial (von Willebrand factor) and monocytic (CD14) markers (31). ''Late'' EPCs develop after 2-3 weeks of culture and have the characteristics of endothelial lineage-like cobblestone pattern (1,8) and the expression of endothelial nitric oxide synthase (8). However, the origin of the double-positive EPCs is still under debate.…”

“…Stem cells within the bone marrow usually exist in a quiescent state and specific signals stimulate the stem cells to differentiate and to be mobilized into the systemic circulation. Beside humoral factors such as cytokines (51)(52)(53), hormones (51,53,54), chemokines (37,55), and drugs (56-58), exercise training (ET) has been shown to increase the number of circulating EPCs (8,9,59,60).…”