Circulating progenitor cells and coronary microvascular dysfunction: Results from the NHLBI-sponsored Women's Ischemia Syndrome Evaluation - Coronary Vascular Dysfunction Study (WISE-CVD).

BACKGROUND AND AIMS

Ischemia stimulates a reparative response resulting in mobilization of circulating progenitor cells (CPCs). We hypothesized that women with chronic myocardial ischemia from coronary microvascular disease (CMD) will mobilize CPCs.

METHODS

In 123 women with ischemic symptoms and signs but no obstructive coronary artery disease (CAD) enrolled in the Women's Ischemia Syndrome Evaluation - Coronary Vascular Dysfunction Study (WISE-CVD), we measured coronary flow reserve (CFR) in response to intracoronary adenosine. Peripheral blood CPCs were measured using flow cytometry for expression of CD34, CD133, CXCR4, and VEGFR2.

RESULTS

Subjects were 53 ± 11 years, BMI 30 ± 8; 44% hypertensive, 11% diabetic, 23% hyperlipidemic and 7% smokers. Lower CFR correlated inversely with higher levels of hematopoietic-enriched CD34+ (r = -0.23, p = 0.011), CD34+/CD133+ (r = -0.24, p = 0.008), and CD34+/CXCR4+ (r = -0.19, p = 0.036) cells. In multivariable regression analyses, after adjusting for traditional cardiovascular risk factors, lower CFR remained significantly associated with elevated levels of CD34+ (β -0.18, p = 0.042), CD34+/CD133+ (β -0.24, p = 0.036), and CD34+/CXCR4+ (β -0.22, p = 0.050) cells. We found no association between CFR and CD34+/VEGFR2+ cells.

CONCLUSIONS

In women with non-obstructive CAD, impaired CFR is associated with higher levels of CPCs, suggesting that chronic myocardial ischemia from CMD stimulates CPC mobilization. The functional significance of elevated CPCs in these subjects requires further investigation as a potential biomarker and treatment target.