Transient heart rate reduction improves acute decompensated heart failure-induced left ventricular and coronary dysfunction.

AIMS: Acute decompensated heart failure (ADHF), a live-threatening complication of heart failure (HF), associates a further decrease of the already by HF-impaired cardiac function with an increase in heart rate. We evaluated, using a new model of ADHF, whether heart rate reduction (HRR) opposes the acute decompensation-related aggravation of cardiovascular dysfunction. METHODS AND RESULTS: Cardiac output (echocardiography), cardiac tissue perfusion (magnetic resonance imaging), pulmonary wet weight, and in vitro coronary artery relaxation (Mulvany) were assessed 1 and 14 days after acute decompensation induced by salt-loading (1.8 g/kg, PO) in rats with well-established HF due to coronary ligation. HRR was induced by administration of the If current inhibitor S38844, 12 mg/kg PO twice daily for 2.5 days initiated 12 h or 6 days after salt-loading (early or delayed treatment, respectively). After 24 h, salt-loading resulted in acute decompensation, characterized by a reduction in cardiac output (HF: 130 ± 5 mL/min, ADHF: 105 ±  8 mL/min; P < 0.01), associated with a decreased myocardial perfusion (HF: 6.41 ± 0.53 mL/min/g, ADHF: 4.20 ± 0.11 mL/min/g; P < 0.01), a slight increase in pulmonary weight (HF: 1.68 ± 0.09 g, ADHF: 1.81 ± 0.15 g), and impaired coronary relaxation (HF: 55 ± 1% of pre-contraction at acetylcholine 4.5 10-5  M, ADHF: 27 ± 7 %; P < 0.01). Fourteen days after salt-loading, cardiac output only partially recovered (117 ± 5 mL/min; P < 0.05), while myocardial tissue perfusion (4.51 ± 0.44 mL/min; P < 0.01) and coronary relaxation (28 ± 4%; P < 0.01) remained impaired, but pulmonary weight further increased (2.06 ± 0.15 g, P < 0.05). Compared with untreated ADHF, HRR induced by S38844 improved cardiac output (125 ± 1 mL/min; P < 0.05), myocardial tissue perfusion (6.46 ± 0.42 mL/min/g; P < 0.01), and coronary relaxation (79 ± 2%; P < 0.01) as soon as 12 h after S38844 administration. These effects persisted beyond S38844 administration, illustrated by the improvements in cardiac output (130 ± 6 mL/min; P < 0.05), myocardial tissue perfusion (6.38 ± 0.48 mL/min/g; P < 0.01), and coronary relaxation (71 ± 4%; P < 0.01) at Day 14. S38844 did not modify pulmonary weight at Day 1 (1.78 ± 0.04 g) but tended to decrease pulmonary weight at Day 14 (1.80 ± 0.18 g). While delayed HRR induced by S38844 never improved cardiac function, early HRR rendered less prone to a second acute decompensation. CONCLUSIONS: In a model mimicking human ADHF, early, but not delayed, transient HRR induced by the If current inhibitor S38844 opposes acute decompensation by preventing the decompensated-related aggravation of cardiovascular dysfunction as well as the development of pulmonary congestion, and these protective effects persist beyond the transient treatment. Whether early transient HRR induced by If current inhibitors or other bradycardic agents, i.e. beta-blockers, exerts beneficial effects in human ADHF warrants further investigation.

Short-and long-term administration of imeglimin counters cardiorenal dysfunction in a rat model of metabolic syndrome.

INTRODUCTION: Imeglimin, a glucose-lowering agent targeting mitochondrial bioenergetics, decreases reactive oxygen species (ROS) overproduction and improves glucose homeostasis. We investigated whether this is associated with protective effects on metabolic syndrome-related left ventricular (LV) and vascular dysfunctions. METHODS: We used Zucker fa/fa rats to assess the effects on LV function, LV tissue perfusion, LV oxidative stress and vascular function induced by imeglimin administered orally for 9 or 90 days at a dose of 150 mg/kg twice daily. RESULTS: Compared to untreated animals, 9- and 90-day imeglimin treatment decreased LV end-diastolic pressure and LV end-diastolic pressure-volume relation, increased LV tissue perfusion and decreased LV ROS production. Simultaneously, imeglimin restored acetylcholine-mediated coronary relaxation and mesenteric flow-mediated dilation. One hour after imeglimin administration, when glucose plasma levels were not yet modified, imeglimin reduced LV mitochondrial ROS production and improved LV function. Ninety-day imeglimin treatment reduced related LV and kidney fibrosis and improved kidney function. CONCLUSION: In a rat model, mimicking Human metabolic syndrome, imeglimin immediately countered metabolic syndrome-related cardiac diastolic and vascular dysfunction by reducing oxidative stress/increased NO bioavailability and improving myocardial perfusion and after 90-day treatment myocardial and kidney structure, effects that are, at least in part, independent from glucose control.

Short- and long-term administration of the non-steroidal mineralocorticoid receptor antagonist finerenone opposes metabolic syndrome-related cardio-renal dysfunction.

AIM: To determine whether non-steroidal mineralocorticoid receptor (MR) antagonists oppose metabolic syndrome-related end-organ, i.e. cardiac, damage. MATERIALS AND METHODS: In Zucker fa/fa rats, a rat model of metabolic syndrome, we assessed the effects of the non-steroidal MR antagonist finerenone (oral 2 mg/kg/day) on left ventricular (LV) function, haemodynamics and remodelling (using echocardiography, magnetic resonance imaging and biochemical methods). RESULTS: Long-term (90 days) finerenone modified neither systolic blood pressure nor heart rate, but reduced LV end-diastolic pressure and LV end-diastolic pressure-volume relationship, without modifying LV end-systolic pressure and LV end-systolic pressure-volume relationship. Simultaneously, long-term finerenone reduced both LV systolic and diastolic diameters, associated with reductions in LV weight and LV collagen density, while proteinuria and renal nGAL expression were reduced. Short-term (7 days) finerenone improved LV haemodynamics and reduced LV systolic diameter, without modifying LV diastolic diameter. Moreover, short-term finerenone increased myocardial tissue perfusion and reduced myocardial reactive oxygen species, while plasma nitrite levels, an indicator of nitric oxide (NO) bio-availability, were increased. CONCLUSIONS: In rats with metabolic syndrome, the non-steroidal MR antagonist finerenone opposed metabolic syndrome-related diastolic cardiac dysfunction and nephropathy. This involved acute effects, such as improved myocardial perfusion, reduced oxidative stress/increased NO bioavailability, as well as long-term effects, such as modifications in the myocardial structure.