Quantitative analysis calculating integrated optical density (IOD)/area ratio by Image Pro Plus confirmed the results, showing either PLLA or IM group expressed significantly more BNP in tissues (PLLA: 0.09 ± 0.017, IM: 0.08 ± 0.008, PLLA-HA/ACE2: 0.02 ± 0.004) (Fig. 7g), which represented these groups enduring worse volume stress and developing heart failure after large scale cardiac fibrosis. The gene discussed is ACE2; the disease is heart failure.