HMOX1 and cardiomyopathy: In hemin-treated ZLs, HO-1, HO activity and cGMP were enhanced by 3.1-, 2.8-, and 2.4-fold, respectively, as compared to 8.4-, 11.3-, and 3.4-fold, respectively, in hemin-treated ZFs, suggesting greater selectivity of hemin to the HO system in unhealthy ZFs characterized obesity, insulin resistance, and cardiomyopathy [29].