Mobilized Muse Cells After Acute Myocardial Infarction Predict Cardiac Function and Remodeling in the Chronic Phase

Background: Multilineage differentiating stress-enduring (Muse) cells are SSEA3(+) and CD105(+) double-positive pluripotent-like stem cells. We aimed to examine the mobilization of Muse cells into peripheral blood after acute myocardial infarction (AMI) and their effects on left ventricular (LV) function and remodeling. Methods and Results: In 79 patients with AMI, 44 patients with coronary artery disease (CAD), and 64 normal subjects (Control), we measured the number of Muse cells in the peripheral blood by fluorescence-activated cell sorting. Muse cells were measured on days 0, 1, 7, 14, and 21 after AMI. Plasma sphingosine-1-phosphate (S1P) levels were measured. Cardiac echocardiography was performed in the acute (within 7 days) and chronic (6 months) phases of AMI. Muse cell number on day 1 was significantly higher in the AMI (276 +/- 137 cells/100 mu L) than in the CAD (167 +/- 89 cells/100 mu L) and Control (164 +/- 125 cells/100 mu L) groups. Muse cell number peaked on day 1, and had gradually decreased on day 21. Muse cell number positively correlated with plasma S1P levels. Patients with a higher increase in the number of Muse cells in the peripheral blood but not those with a lower increase in number of Muse cells in the acute phase showed improved LV function and remodeling in the chronic phase. Conclusions: Endogenous Muse cells were mobilized into the peripheral blood after AMI. The number of Muse cells could be a predictor of prognosis in patients with AMI.