Therapeutic benefits of CD90-negative cardiac stromal cells in rats with a 30-day chronic infarct.

Cardiac stromal cells (CSCs) can be derived from explant cultures, and a subgroup of these cells is viewed as cardiac mesenchymal stem cells due to their expression of CD90. Here, we sought to determine the therapeutic potential of CD90-positive and CD90-negative CSCs in a rat model of chronic myocardial infarction. We obtain CD90-positive and CD90-negative fractions of CSCs from rat myocardial tissue explant cultures by magnetically activated cell sorting. In vitro, CD90-negative CSCs outperform CD90-positive CSCs in tube formation and cardiomyocyte functional assays. In rats with a 30-day infarct, injection of CD90-negative CSCs augments cardiac function in the infarct in a way superior to that from CD90-positive CSCs and unsorted CSCs. Histological analysis revealed that CD90-negative CSCs increase vascularization in the infarct. Our results suggest that CD90-negative CSCs could be a development candidate as a new cell therapy product for chronic myocardial infarction.