Abstract 10372: Human Cardiomyocyte Protection From Apoptosis by Cardiac Progenitor Cell Secreted Factors

• Published in: Circulation (New York, N.Y.) N.Y.), 2019-11, Vol.140 (Suppl_1 Suppl 1), p.A10372-A10372
• Main Authors: Constantinou, Chrystalla, Noseda, Michela, Chaves, Patricia, Miranda, Antonio M, Bellahcene, Mohamed, Cheng, Kevin, Harding, Sian, Schneider, Michael D
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.140.suppl_1.10372

Myocardial infarction is the foremost cause of death globally, and progression to heart failure is proportional to infarct size. Prevention of cardiomyocyte loss is vital to halt cardiac damage. Our previous data show that intramyocardial injection of cardiac progenitors (CPC) at time of infarct, results in remuscularization and scar size reduction. However, myogenic progenitors are poorly retained, hence paracrine signals might explain the observed improvement of cardiac function. Here paracrine effects of cardiac progenitors on human pluripotent stem cell derived cardiomyocytes (hPSCM) were investigated.To demonstrate whether CPC-conditioned media injections adequately prevent cardiomyocyte death, permanent ligation was performed in mice as a proof of principle in vivo. We then established in vitro systems to analyse the CPC-secretome effects in hPSCM. Conditioned medium injected into the infarct border zone at the time of coronary artery ligation reduced the proportion of apoptotic (TUNEL+) cardiomyocytes from 36.5%±7.8 to 9.8%±3.5 (n=6). Transwell coculture assays and conditioned medium experiments demonstrated that the secretome from mouse CPCs suppresses death from menadione induced-stress in hPSCM (DRAQ7) from 47.2%±2.9 to 2.7%±0.9 (n=9). Mechanistically, cardiomyocyte protection involved reducing apoptosis from 53.2%±5.1 to 12.6%±2.5 (n=9), preserving mitochondrial membrane potential (TMRM) from 26.4%±9.2 to 58.6%±3 (n=6) and inhibiting reactive oxygen species (CellROX) from 55%±6.3 to 12.6±2.1 (n=12). Functional investigations demonstrated that CPC-conditioned media preserve hPSCM beating frequency, calcium cycling amplitude (Fura-4F), and action potential characteristics (Di-4-ANEPPS, FluoVolt) following oxidative stress. Protection is exosome-independent and mediated by thermolabile molecules more than 3kDa in size. In summary, hPSCM were employed as a target platform for paracrine protection establishing their versatility to investigate biological signals that augment human cardiac muscle survival. CPC-secreted mediators impinge on apoptosis, preserve mitochondrial polarisation, suppress reactive oxygen content and inhibit loss of functional features in hPSCM exposed to oxidative stress.