Background: Vascular progenitor cells (VPCs) are a heterogeneous population, containing a subpopulation co-expressing both endothelial and smooth muscle phenotypes. This study sought to determine whether the level of this subpopulation correlated with the coronary Gensini score.
Methods and results: VPCs were cultivated in 50 patients undergoing coronary angiography. A subpopulation of VPCs expressed both endothelial (VE-cadherin [VE-Cad]) and smooth-muscle phenotypes (α-smooth muscle actin [α-SMA]). Correlations of the VE-Cad(low)α-SMA(+) VPC level and adhesion molecule expression by VPCs with the Gensini score were investigated. The association between the amount of this subpopulation and the development of intimal hyperplasia (IH) was also estimated in a vascular injury animal model. Both the number of VE-Cad(low)α-SMA(+) VPCs (P = 0.002) and the expression level of intracellular adhesion molecule (ICAM)-1 by VPCs (P = 0.008) correlated with the Gensini score. However, only the number of VE-Cad(low)α-SMA(+) VPCs (P = 0.004) and the blood level of low-density lipoprotein cholesterol (P = 0.016) were parameters independently associated with the Gensini score in multivariate analysis. Furthermore, in an animal model of injecting VPCs into SCID mice after femoral artery wire injury, a higher number of VE-Cad(low)α-SMA(+) VPCs correlated with greater IH (r = 0.69, P<0.0001).
Conclusions: The level of VE-Cad(low)α-SMA(+) VPCs was associated with the severity of coronary atherosclerosis as quantified by the Gensini score. Manipulating this subpopulation may provide a way of attenuating atherosclerosis in the future.