In the exosome only group, all the rats exhibited cardiomyocyte hypertrophy, bundles of large longitudinally arranged hypertrophied heart muscle cells with large basophilic reticular nuclei (Figure 7). In addition, two rats showed focal hyper-eosinophilia and increased size of cardiomyocyte nuclei with the appearance of multinucleated cardiomyocytes were observed, with one animal exhibiting perivascular lymphoplasmacytic infiltration (Figure 7). Mild atherosclerotic changes in large vessels were observed in all cases. A minimal perivascular fibrosis observed in one of the animals and the other two rats showed mild cases of perivascular fibrosis (Figure 7). Interestingly, mild form of interstitial fibrosis (Figures 7) was observed in all three animals in this group (Table 1).