REN and heart failure: Induction of heart failure in rats has significantly increased circulating NT-proBNP (980 ± 116.71 pg/ml), MMP9 (15.85 ± 0.57 ng/ml), troponin-I (3.09 ± 0.147 ng/ml), CK-MB (31.55 ± 1.69 ng/ml), renin (736 ± 45.8 pg/ml), urea (52.1 ± 1.57 mg/dl), and creatinine (0.92 ± 0.04 mg/dl).