The Intrapericardial Delivery of Extracellular Vesicles from Cardiosphere-Derived Cells Stimulates M2 Polarization during the Acute Phase of Porcine Myocardial Infarction

Abstract

Acute myocardial infarction triggers a strong inflammatory response in the affected cardiac tissue. New therapeutic tools based on stem cell therapy may modulate the unbalanced inflammation in the damaged cardiac tissue, contributing to the resolution of this pathological condition. The main goal of this study was to analyze the immunomodulatory effects of cardiosphere-derived cells (CDCs) and their extracellular vesicles (EV-CDCs), delivered by intrapericardial administration in a clinically relevant animal model, during the initial pro-inflammatory phase of an induced myocardial infarction. This effect was assessed in peripheral blood and pericardial fluid leukocytes from infarcted animals. Additionally, cardiac functional parameters, troponin I, hematological and biochemical components were also analyzed to characterize myocardial infarction-induced changes, as well as the safety aspects of these procedures. Our preclinical study demonstrated a successful myocardial infarction induction in all animals, without any reported adverse effect related to the intrapericardial administration of CDCs or EV-CDCs. Significant changes were observed in biochemical and immunological parameters after myocardial infarction. The analysis of peripheral blood leukocytes revealed an increase of M2 monocytes in the EV-CDCs group, while no differences were reported in other lymphocyte subsets. Moreover, arginase-1 (M2-differentiation marker) was significantly increased in pericardial fluids 24 h after EV-CDCs administration. In summary, we demonstrate that, in our experimental conditions, intrapericardially administered EV-CDCs have an immunomodulatory effect on monocyte polarization, showing a beneficial effect for counteracting an unbalanced inflammatory reaction in the acute phase of myocardial infarction. These M2 monocytes have been defined as "pro-regenerative cells" with a pro-angiogenic and anti-inflammatory activity.

Large Animal Models of Cell-Free Cardiac Regeneration

“…Recently, Lopez et al [ 36 ] investigated the effects of an intrapericardial injection of CDCexo 72 h after AMI ( n = 18) [ 37 ]. Blood sampling 24 h after treatment revealed an increase in circulating anti-inflammatory CD14+ CD163+ M2 macrophages in the treatment group, as well as an upregulation of arginase-1, which is considered an M2-differentiation marker, in the pericardial fluid.…”

“…Blood sampling 24 h after treatment revealed an increase in circulating anti-inflammatory CD14+ CD163+ M2 macrophages in the treatment group, as well as an upregulation of arginase-1, which is considered an M2-differentiation marker, in the pericardial fluid. While they successfully demonstrated that a minimally invasive intrapericardial adminstration of CDCexo was safe and had a local and systemic effect on inflammatory cells, they did not find any significant differences in LVEF or infarct size 10 weeks after treatment [ 37 ].…”

“…[ 25 ] administration of MSC-CM or EPC-CM was effective in improving functional heart parameters, while i.c. [ 34 ], intrapericardial [ 37 ], and i.v. [ 38 ] administration of EVs was not.…”

Is There Preclinical and Clinical Value for 19F MRI in Stem Cell Cardiac Regeneration?

“…Observed variations documented by the findings of various completed and ongoing clinical trials 1 – 3 , 12 that have been/are focusing on mesenchymal SCs, cardiac progenitor cells (CPCs), embryonic stem cells (ESCs), and inducible pluripotent SCs (iPSCs) ( Table 1 ) may be attributed to (among others) the differences in the design and cell preparation parameters, suitable cell type(s), administration route(s), delivery time 13 , and end points 12 . The existing hypotheses for documented SC effects include (a) direct (cardiomyogenesis and vasculogenesis) and (b) indirect (attenuation of inflammatory responses and fibrosis, promotion of angiogenesis, and enhancement of cellular viability via paracrine/other signaling/post-translational modification mechanisms) mechanisms 12 , 14 , 15 . Despite the ambivalent clinical outcomes, preclinical successes have been documented in rodents and mammals, as manifested by feasible and safe SC administration, the capacity to change the course of the MI, and improved remodeling and cardiac functional indices (e.g., ejection fraction, ventricular volumes, etc.)…”

“…Overall, iPSCs 13 , 14 are more advantageous but still face critical challenges 21 that can be potentially addressed with next generation therapies, including polymeric biodegradable scaffolds and three-dimensional constructs. These constitute optimal test beds that can be used to mediate the proinflammatory/fibrotic/apoptotic responses, in combination with the use of cytokines, microribonucleic acid (miRNA), growth factors, noncoding RNA constructs, and extracellular vesicles, to achieve improved engraftment 1 , 22 and viability under hypoxic states, immunogenicity, electrical topology 23 , cellular differentiation 24 , and the elimination of arrythmogenic events 19 .…”