Background: Experimental results from various animal models and preliminary clinical data have indicated the capacity of bone marrow-derived stem cells to home into infarcted heart tissue and promote cardiac repair. Erythropoietin (EPO) has been shown to increase the number of active endothelial progenitor cells in humans.
Objective: To determine if mobilization of hematopoietic progenitor cells (CD34-positive [CD34+], CD117+ or CD133+ cells) into peripheral blood represents a physiological reaction during acute myocardial infarction (AMI) and if EPO is involved in the regulation of this process.
Methods: Peripheral blood samples taken from 10 patients with AMI, seven patients with angina pectoris (AP) and five patients without coronary artery disease who underwent coronary angiography (controls) were analyzed for the presence of CD34+, CD117+ or CD133+ cells using flow cytometry. In addition, EPO plasma levels were determined by an ELISA. Samples were drawn between days 1 and 3 and days 4 and 8 after ischemic events.
Results: Increased mean values of CD34+ and CD133+ cells were found in patients with either AMI or AP compared with the control group. Subjects with AMI had augmented cell counts of CD117+ and CD34+ progenitor cells compared with patients with AP. EPO levels were higher in patients with AMI or AP compared with the control group.
Conclusions: AMI in humans appears to serve as a stimulus for CD117+ and CD34+ progenitor cell mobilization. Increased EPO levels may play a role in the regulation of this process.
Keywords: Cell mobilization; Erythropoietin; Myocardial infarction; Progenitor cells; Stem cells.