Discussion
acute myocardial infarction, myocardial cell injury, exosomes decrease
ACUTE MYOCARDIAL INFARCTION, DISEASE, HYPOXIC, AMI, ARTICULAR DISEASE
As a global industrial standard for cell therapy products (CTPs), the evaluation of potency plays a key role in defining the quality of the CTP. The development of the potency assay is based on the quantitative measure of a relevant biologic function linked to the mechanism of action of the CTP for that particular disease indication. The potency assay is a critical quality control measure required for batch release to demonstrate its biological activity and guarantee quality, consistency, and stability between batchesFirst, we showed that ProtheraCytes secrete paracrine factors such as VEGF that can promote endothelial and cardiac repair of damaged myocardial tissue. Indeed, the concentration of VEGF found in the culture supernatants was significantly correlated to the numbers of CD34Secondly, we characterized ProtheraCytes-derived exosomes and determined that their average size is 86.7 ± 10.17 nm, in line with previously reported results for CD34miR-126 and miR-130a were also enriched in CD34Exo. Luo and colleagues have shown that miR-126-enriched exosomes decrease myocardial cell injury and expression of fibrosis-related proteins under hypoxic conditions and promote microvascular generation and migration in vitroWe also identified other miRNAs enriched in the Protheracytes derived exosomes (miR-199a, miR-590) that have the ability to induce therapeutic regeneration of damaged tissue and were reported to play an essential role in heart development, disease and regenerationWe then analyzed the expression profile of angiogenic and vasculogenic genes in ProtheraCytes from AMI patients and healthy volunteers and found only small differences between them. Only a few proangiogenic genes such as THSD7A, ANGPT2, and TGFA and vasculogenic genes including RASIP1 and TGFBR3 were upregulated in AMI patient samples. Flow cytometry characterization showed that ProtheraCytes express stem cell and endothelial surface markers, although some of these markers are also expressed by other cell types. Finally, as CD34 is a marker of endothelial progenitor cellsOur data showed that ProtheraCytes are able to secrete paracrine factors, such as VEGF and miRNAs that may play a role in angiogenesis, survival and cardiac regeneration, promote endothelial repair, and decrease apoptosis of damaged myocardial tissue. Based on the evaluation of all the data, we chose the VEGF ELISA as a potency assay, because it is a fast, reliable, quantitative assay that allows for the timely batch release before ProtheraCytes are shipped to the clinic for injection. This potency assay has been previously used by other sponsors in cell therapy trials for acute myocardial infarction