Abstract 15760: The Relationship Between Distinct Endothelial Progenitor Cell Populations and the Physiological Severity of Coronary Artery Disease in Humans
Objectives: Endothelial progenitor cells (EPCs) are implicated in cardiovascular repair and regeneration. However, previous studies showed conflicting results when relating endogenous EPCs to extent of coronary disease. Possible reasons for these include heterogeneity of EPC definitions and exclusive reliance on coronary angiography alone to assess coronary disease severity, a technique which has limited correlation with the haemodynamic significance of coronary artery disease. More recently, two phenotypically distinct EPC populations (early EPCs and late outgrowth endothelial cells [OECs]) with different angiogenic properties in-vitro have been described, but their role in humans has rarely been compared. We hypothesized that distinct EPC populations exhibit differing relationships with the hemodynamic extent of coronary macrovascular disease in humans.
Methods: We assessed the hemodynamic extent of coronary macrovascular disease by measuring the fractional flow reserve (FFR=hyperemic distal coronary/arterial pressure) during coronary angiography in consecutive patients (n=29) with single vessel disease involving the left anterior descending (LAD) artery. EPCs were isolated from peripheral blood, and EPC counts (DilAcLDL+/Ulex+ cells, colonies and flow cytometry) and angiogenic functional assays were performed.
Results: FFR, a measure of the hemodynamic significance of epicardial LAD disease, correlated positively with OEC counts (r=0.589, p=0.03). In addition, FFR correlated positively with OEC migration (r=0.444, p=0.02) assessed using a Boyden chamber assay. FFR also correlated positively with CD34+/CD45+ EPC counts (r=0.45, p=0.04). In contrast, no such relationship was established with FFR and early EPCs with regards to counts and angiogenic function (p=NS).
Conclusion: We provide evidence that putative EPC populations exhibit differing relationships with the hemodynamic extent of coronary macrovascular disease in humans. In particular, the number and function of OECs, in contrast with early EPCs, are correlated with coronary FFR, consistent with a role for these cells in coronary vascular repair.
- © 2011 by American Heart Association, Inc.