Cardiac Mesenchymal Cells Cultured at Physiologic Oxygen Tension Have Superior Therapeutic Efficacy in Heart Failure Caused by Myocardial Infarction.

Stem/progenitor cells are usually cultured at atmospheric O tension (21%); however, since physiologic O tension in the heart is ∼5%, using 21% O may cause oxidative stress and toxicity. Cardiac mesenchymal cells (CMCs), a newly discovered and promising type of progenitor cells, are effective in improving left ventricle (LV) function after myocardial infarction (MI). We have previously shown that, compared with 21% O, culture at 5% O increases CMC proliferation, telomerase activity, telomere length, and resistance to severe hypoxia .

Myocardial Reparative Properties of Cardiac Mesenchymal Cells Isolated on the Basis of Adherence.

Background: The authors previously reported that the c-kit-positive (c-kit) cells isolated from slowly adhering (SA) but not from rapidly adhering (RA) fractions of cardiac mesenchymal cells (CMCs) are effective in preserving left ventricular (LV) function after myocardial infarction (MI).

Objectives: This study evaluated whether adherence to plastic alone, without c-kit sorting, was sufficient to isolate reparative CMCs.

Methods: RA and SA CMCs were isolated from mouse hearts, expanded in vitro, characterized, and evaluated for therapeutic efficacy in mice subjected to MI.