Regenerative medicine therapy: adipose derived extracellular vesicles in viral myocarditis

Objective: Myocarditis, inflammation of the heart muscle, is an autoimmune heart disease that can be caused by viruses, bacteria and toxins. Myocarditis can lead to dilated cardiomyopathy (DCM) and heart failure. Currently there are no disease-specific therapies for treating myocarditis or preventing progression to DCM. Adipose Extracellular Vesicles (AEVs) are lipid bilayer nanoparticles that are released into the outside environment of adipocytes and provide promising regenerative potential for inflammatory diseases like myocarditis. Methods: Lipoaspirate was obtained from women and men and AEVs isolated from the lipoaspirate using tangential flow filtration. We injected wild type male BALB/c mice with 250uL AEVs (1×10^10 EV/mL) intraperitoneally or sucrose control on day -1, 0, 1 with viral infection on day 0. Mice were harvested on day 10 post infection at the peak of myocarditis. Results: We found that male mice treated with AEVs from a female patient had a significantly higher body weight (p=0.0003), less calcification in the gut (p=0.001) and less myocardial inflammation (p=0.007) than controls. Mouse hearts analyzed by qRT-PCR revealed that AEV treated mice had significantly lower relative gene expression of cell markers for total immune cells (CD45, p=0.002), macrophages (CD11b, p=0.002, F4/80, p=0.0004); specifically M2 macrophages (Chi313, p=0.003), as well as CD3+ (p=0.007) and CD4+ T cells (p=0.01) than controls. Additionally, we found that mice treated with AEVs from a male patient also had significantly less myocardial inflammation (p=0.01). Conclusion: AEVs could provide an innovative therapy to reduce cardiac inflammation and decrease the risk of developing DCM following myocarditis