Intramyocardial Injection Of Heart Tissue-Derived Extracellular Matrix Improves Cardiac Function In A Rat Myocardial Infarction Model

Tissue‐derived decellularized extracellular matrix (ECM) particles were made from hearts of Fischer rats. One week after left coronary ligation in Fischer rats, saline or ECM particle suspension (75 ìl) was directly injected into the myocardial infarcted area. At 6 weeks after injection, left ventriculography demonstrated that LV ejection fraction was significantly greater in the ECM‐treated group (56.7±1.4%, n=19) than in the saline‐treated group (52.4±1.5%, n=17; p=0.043). Echocardiography showed that fractional shortening was significantly increased in the ECM‐treated group (26.2±2.2%) compared to the saline group (17.8±1.5%; p=0.0034). ECM implantation significantly increased the transmural thickness of the infarcted LV wall (0.602±0.029 mm) compared to the saline group (0.484±0.03 mm, p=0.0084). Infarct expansion index was significantly lower in the ECM‐treated group (1.053±0.051) compared to the saline group (1.382±0.096, p=0.0058). No injected ECM were identified within the infarcted area in H&E, and picrosirius red staining, suggesting that native tissue regenerated into the implanted ECM. There was a trend for smaller post‐mortem LV volume (349±12 ìl) in the ECM‐treated group compared with 371±11 ìl in the saline group. Implantation of heart tissue‐derived decellularized ECM thickens the LV infarcted wall and improves LV function after myocardial infarction in rats.