Abstract 17340: Stem Cell Source of Exosomes Determines Their Cardioprotective Effect

Exosomes (Exo) released from stem cells play a critical role in alleviating ischemic myocardial injury. They are long-lived in body fluids with longer circulating half-life and cellular effects. To better understand Exo mediated therapy for ischemic myocardium, we used mesenchymal stem cells (MSCs) from adipose tissue (AD-MSC) and bone marrow (BM-MSC), and compared the effects of Exo derived separately from them on the cardiomyocyte (CM) protection against ischemic injury. MSCs were isolated from adipose tissue and bone marrow of 6-8 week-old mice. Exo were collected from conditioned medium using ExoQuick-TC Exosome Precipitation Solution. CMs were obtained from ventricles of 2-day-old rats, and were exposed to hypoxic culture (1% O 2 , 5%CO 2 , and 94% N 2 ) for 72 hrs. There was no difference on surface markers expression (Fig. A), although the proliferation speed was faster (Fig. B) in AD-MSCs compared to that in BM-MSCs. The amount of Exo secreted from AD-MSCs (Exo-AD) was more than that from BM-MSCs (Exo-BM) (Fig. C). Exo significantly protected CMs against the injury induced by exposure to hypoxia for 72 hrs (Fig. D). The survival rate was significantly higher in the group treated with Exo-AD derived from same number of MSCs than those from Exo-BM (Fig. E). However, the cell survival was better in CMs treated with Exo-BM compared to that that treated with Exo-AD when same amount of Exo were used (Fig. F). AD-MSCs proliferated faster and secreted more Exo compared to BM-MSCs. It is concluded that source of Exo may be important in designing their therapeutic effects.