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To assess myocardial function and scar evolution after implanting an engineered bioactive impedance graft (EBIG) in a swine myocardial infarction (MI) model.
The EBIG comprises a scaffold of decellularized human pericardium, green fluorescent protein-labeled porcine adipose tissue-derived progenitor cells (pATPCs), and a customized-design electrical impedance spectroscopy (EIS) monitoring system. Cardiac function was evaluated noninvasively by using magnetic resonance imaging (MRI). Scar healing was evaluated by using the EIS system within the implanted graft. Infarct size, fibrosis, and inflammation were explored by histopathology.
Upon sacrifice 1 month after the intervention, MRI detected a significant improvement in left ventricular ejection fraction (7.5% ± 4.9% vs. 1.4% ± 3.7%; p = 0.038) and stroke volume (11.5 ± 5.9 ml vs. 3 ± 4.5 ml; p = 0.019) in EBIG-treated animals. Noninvasive EIS data analysis showed differences in both impedance magnitude ratio (-0.02 ± 0.04 per day vs. -0.48 ± 0.07 per day; p = 0.002) and phase angle slope (-0.18° ± 0.24° per day vs. -3.52° ± 0.84° per day; p = 0.004) in EBIG compared with control animals. Moreover, in EBIG-treated animals, the infarct size was 48% smaller (3.4% ± 0.6% vs. 6.5% ± 1%; p = 0.015), less inflammation was found by means of CD25+lymphocytes (0.65 ± 0.12 vs. 1.26 ± 0.2; p = 0.006), and a lower collagen I/III ratio was detected (0.49 ± 0.06 vs. 1.66 ± 0.5; p = 0.019).
An EBIG composed of acellular pericardium refilled with pATPCs significantly reduces infarct size and improves cardiac function in a preclinical model of MI. Noninvasive EIS monitoring is useful for tracking differential scar healing in EBIG-treated animals, which is confirmed by less inflammation and altered collagen deposit.