Circulation of CD34⁺ progenitor cell populations in patients with idiopathic dilated and ischaemic cardiomyopathy (DCM and ICM)

Aims: This study aimed at analysing the endogenous stem cell circulation in patients suffering from idiopathic dilated cardiomyopathy (DCM) and ischaemic cardiomyopathy (ICM). Methods and results: Cytokines in peripheral blood were analysed using enzyme-linked immunosorbent assay and circulating CD34 ⁺ stem cell populations (CD34⁺CD133⁺, CD34 ⁺CD31⁺, CD34⁺CXCR-4⁺) were measured by flow cytometry in DCM patients (n = 25), ICM patients (n = 15), and controls (n = 10). Explanted DCM (n = 5), ICM (n = 4) and normal hearts (n = 5) were analysed for the expression of several homing factors [stromal cell-derived factor-1 (SDF-1), Stem cell factor (SCF), HIF-1a, vascular cell adhesion molecule (VCAM), and Hepatocyte growth factor] by quantitative real-time polymerase chain reaction (PCR). SDF-1 was significantly elevated and positively correlated with brain natriuretic peptide (BNP) in peripheral blood of DCM and ICM patients showing the same New York heart association- (NYHA) class. In DCM patients circulating CD34⁺ cell populations were significantly increased in comparison to ICM patients and controls. mRNA of SDF-1, SCF, HIF-1a, and VCAM related to glyceraldehyde-3-phosphate dehydrogenase was significantly upregulated in ICM hearts when compared with DCM hearts and controls. Conclusion: Myocardial homing factors are upregulated in ICM when compared with DCM hearts. Reduced homing of stem cells might therefore explain the increased number of CD34⁺ cells in DCM patients. These findings may open a new insight into the pathology and the treatment of idiopathic DCM.