Diabetes mellitus impairs CD133+ progenitor cell function after myocardial infarction

Circulating progenitor cells (PC) can positively influence the healing of ischaemic myocardium. Cardiovascular risk factors including diabetes mellitus (DM) may have a negative influence on both number and recruitment of PC. Recent evidence suggests that less differentiated CD133(+)PC contribute to myocardial healing and are promising candidates for therapy. Therefore, we investigated whether DM affects CD133(+)PC. CD133(+)PC were analyzed in patients following acute myocardial infarction and successful reperfusion [acute myocardial infarction (AMI, n = 45) with/without non-insulin-requiring type 2 DM (T2DM)]. Stable coronary artery disease patients (CAD, n = 45) served as stable controls. Number and phenotype of CD133(+)PC were assessed by flow cytometry. CD133(+)PC chemotaxis was assessed towards vascular endothelial growth factor, an angiogenic stimulus upregulated in AMI. The expression of anti-oxidant enzymes in CD133(+)PC was detected by reverse-transcriptase PCR. In non-DM patients, the number of CD133(+)PC increased on day 3 following AMI (P = 0.0001). In contrast, no changes were observed in AMI patients with T2DM. Regarding the function of CD133(+)PC, an enhanced chemotactic response was observed following AMI in both non-DM (P = 0.0001) and T2DM (P = 0.007). However, the AMI-related functional activation was significantly weaker in diabetic patients (P = 0.001). Moreover, the expression of catalase was lower in CD133(+)PC from T2DM. Our results show that T2DM not only limits the abundance of CD133(+)PC following AMI, but also limits their activation. This might be explained by a lower resistance of CD133(+)PC to oxidative stress. Our data provide a possible explanation for the delayed postischaemic vascular healing and myocardial recovery in DM.