Myocardial infarction does not affect circulating hematopoietic stem and progenitor cell self-renewal ability in a rat model

Abstract

Due to the importance of peripheral blood hematopoietic stem and progenitor cells (HPCs) in post-acute regeneration after acute myocardial infarction (MI), the present study aimed to investigate count and secondary replating capacity/self-renewal ability of HPCs in peripheral blood before and two weeks after MI. In nine female Lewis inbred rats (n = 9), myocardial infarction was induced by ligation of the left coronary artery while another nine had surgery without ligation for control purposes. Myocardial infarction was confirmed by troponin I concentrations 24 h after MI. Peripheral blood was withdrawn and fractional shortening (FS) and ejection fraction (EF) of the left ventricle was assessed before (day-0) and 14 days after MI or control surgery (day-14). After mononuclear cell isolation, primary/secondary functional colony-forming unit-granulocyte macrophage (CFU-GM) assays were performed in order to detect the kinetics of functional HPC colony count and cell self-renewal ability in vitro. CFU-GM count and cell self-renewal ability remained unchanged (P > 0.05) in both groups at day-14 without interaction between groups. In the intervention group, higher day-0 CFU-GM counts showed a relation to lower FS on day-14 (ρ = −0.82; P < 0.01). Myocardial infarction did not negatively affect circulating HPC self-renewal ability, which suggests a constant regenerative potential in the post-acute phase. A relation of cardiac contractile function 14 days after MI with circulating CFU-GM count on day-0 might imply functional colony count as a predictive factor for outcome after infarction.

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