WJMSCs Anti-inflammatory Therapy in Acute Myocardial Infarction

At present, although the implementation of timely reperfusion strategies has reduced the acute mortality associated with AMI, improved patient survival has increased the incidence of chronic heart failure, due in large part to adverse remodeling of the damaged left ventricle (LV) following the initial ischemic event. However, recently, pathophysiological mechanisms of AMI reveal that begins immediately after the onset of necrotic cell death with intense sterile inflammation and myocardial infiltration of a variety of immune cell subtypes including neutrophils, monocytes and macrophages during the first several days after MI. Improved understanding in the interactions between cells, extracellular matrix (ECM) and signaling molecules within the injured myocardium have allowed development of novel experimental therapies. These therapies seek to target the intricate balance between pro- and anti-inflammatory pathways in an attempt to limit ischemic injury and prevent subsequent development of heart failure. Mesenchymal stem cells (MSCs), in particular, have emerged as potent paracrine modulators of inflammation that promote myocardial healing after infarction.

The latest cell biological studies have demonstrated that mesenchymal stem cells have a unique immunomodulatory function. MSCs contribute to a critical role in regulating the inflammatory microenvironment and interacting with immune cells, including T cells, B cells, natural killer (NK) cells, and dendritic cells (DCs). MSC induce anti- inflammatory macrophages, inhibit foam cell formation, suppress immune responses of endothelial cells and innate lymphoid cells, and increase phagocytic capacity, which indirectly suppresses T cell proliferation. In mouse AMI models, we found MSCs transplantation significantly reduced the number of inflammatory macrophages (M1), increased the number of anti-inflammatory macrophages (M2) and prevented the expansion of AMI during early stage of AMI. More recently, the paracrine potency might vary with sources and microenvironment of MSCs. MSCs isolated from fetal tissues such as umbilical cord (UC) and UC-blood (UCB) were shown to have increased secretion of anti-inflammatory factors (TGF-β,IL-10) and growth factors than MSCs obtained from adult adipose tissue or bone marrow. Our previous research found that the expression characteristics of special immunomodulatory genes of human umbilical cord Wharton's jelly-derived MSCs (WJMSCs). At present, many studies have demonstrated WJMSC possess s a robust immunomodulatory potential and anti-inflammatory effects through release of secretome consisting of a diverse range of cytokines, chemokines, and extracellular vesicles (EVs), the cross talk and interplay of WJMSCs and local environment reversely control and regulate the paracrine activity of MSCs. Thus WJMSCs are important regulators of immune responses and may hold great potential to be used as a therapeutic in AMI. In particular#safety and feasibility of WJMSCs transplant have been clearly proved by us and other studies in patients with AMI.

Given the current evidence, systemic paracrinemediated anti-inflammatory effects of WJMSCs can drive beneficial in therapy of AMI. These concepts lead to a potentially transformative strategy that intravenous delivery of WJMSCs, through systemic anti-infammatory mechanisms.

Therefore, the investigators performed a double-blind, placebo- controlled trial, randomly assigning 200 patients with AMI to receive three times at 30-day intervals for equal doses of 1x106 /kg of WJMSCs, first time infusing within 24h after AMI or placebo , to investigate the therapeutic efficacy and safety of WJMSCs in patients with acute ST-Segment-Elevation or Non-ST-Segment-elevation myocardial infarction.