Chen, Horng

BACKGROUND: It is unknown whether cardiac resynchronization therapy (CRT) improves systemic metabolomic profile by enhancing left ventricular function. The observational cohort study aimed to investigate the effect of CRT on left ventricular ejection fraction (LVEF) and circulating plasma metabolites in patients who had heart failure with reduced LVEF. METHODS: We prospectively screened patients with ischemic cardiomyopathy and nonischemic cardiomyopathy who received CRT with a defibrillator for LVEF ≤35% according to current guidelines. Clinical assessment included echocardiography and device interrogation. Blood samples for metabolomic analysis were collected before CRT and at 6-month follow-up. Plasma was subjected to gas chromatography-mass spectrometry and 1 H nuclear magnetic resonance-based metabolomic analysis. RESULTS: Totally 92 patients were enrolled, with a mean age of 67.3±11.3 years (37.0% female). LVEF was significantly improved from 28.9±7.6% at baseline to 36.0±11.3% at 6 months ( P <0.001) and to 40.1±12.6% at 12 months ( P <0.001). After CRT, 42 metabolite features were significantly decreased compared with the baseline. The ketone bodies, including 3-hydroxybutyrate ( P <0.001) and acetone ( P =0.01), were reduced. A branched-chain amino acid, isoleucine, was also decreased after CRT ( P =0.01). These metabolomic changes were mainly observed in the nonischemic cardiomyopathy group, while the metabolomic profile in the ischemic cardiomyopathy group was characterized by enhanced amino acid oxidation and elevated levels of lactate and pyruvate. The improvement in LVEF positively correlated with the ratio of changes in ketone bodies and isoleucine. CONCLUSIONS: CRT may modulate the systemic plasma metabolomic profile, which correlated with improvement in left ventricular function in patients with severe heart failure with reduced ejection fraction.

BACKGROUND: Cardiorenal dysfunction with impaired cyclic GMP (cGMP) response is common in patients presenting with acute heart failure (HF). Type V phosphodiesterase (PDEV) is known to be upregulated in HF and may explain the dysfunction of renal response. The aim of this study was to determine whether B-type natriuretic peptide (BNP) alone or in combination with PDEV inhibition improves renal function and increases urinary sodium and cGMP excretion in acute HF. METHODS: This open-label study included 67 patients hospitalized with acute HF and renal dysfunction. Patients were randomized to standard care, low-dose intravenous BNP (0.005 µg/kg per minute), or combination BNP/PDEV inhibition with sildenafil (25 mg q12 hours) for 48 hours. The coprimary end points were the percent change in estimated glomerular filtration rate and blood urea nitrogen from baseline to 48 hours. RESULTS: Treatment with BNP and BNP/PDEV inhibitor significantly increased plasma cGMP at 24 hours (+25.6% [+9.8%, +84.7%] and +60.8% [+32.3%, +103.8%] for BNP and BNP/PDEV versus −13.5% [−29.1%, +14.2%] with standard care; P =0.001). However, there was no significant change in estimated glomerular filtration rate 0 (−10.8%, +12.7%) for standard care versus 0 (−15.3%, +11.8%) for the BNP group versus –8.8% (−14.3%, +8.3%) for the BNP/PDEV group ( P =0.60) or blood urea nitrogen −1.4% (−10.7%, +12.0%) for standard care versus –5.9% (−14.6%, +9.4%) for the BNP group versus +6.9% (−5.3%, +18.8%) for the BNP/PDEV group ( P =0.38) between groups. Hypotension was more common in the BNP/PDEV inhibitor group. CONCLUSIONS: BNP and combination BNP/PDEV inhibition increased plasma cGMP in patients with acute HF but did not improve renal function or urinary sodium/cGMP excretion. Our study does not support the use of intravenous low-dose BNP with or without PDEV inhibition to enhance renal function in patients admitted with acute HF. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT00972569.

Background: cGMP MANP (M-atrial natriuretic peptide) is a best-in-class activator of the pGC-A (particulate guanylyl cyclase A) receptor. Furosemide increases the effectiveness of antihypertensive agents, but activates renin-angiotensin-aldosterone system. We aimed to investigate for the first time cardiorenal and neurohumoral actions of MANP in a genetic model of hypertension in spontaneously hypertensive rats. We also assessed how MANP would potentiate the blood pressure (BP)–lowering actions of furosemide while reducing the production of aldosterone. Methods: Spontaneously hypertensive rats (N=60) were randomized in vehicle, MANP, furosemide, or MANP+furosemide groups. Furosemide (1, 5, 10 mg/kg) was given as a single bolus which in MANP+furosemide groups was followed by a 60-minute infusion of MANP. Results: BP was reduced in MANP300 (300 pmol/[kg·min]) and MANP600 (600 pmol/[kg·min]) groups ( P <0.05) and was accompanied by significant increase in plasma cyclic guanosine monophosphate. Furosemide alone reduced BP but less compared with MANP with no change in plasma cyclic guanosine monophosphate. MANP+furosemide resulted in the greatest BP reduction and significant increase in plasma cyclic guanosine monophosphate in Fs5+MANP300, Fs10+MANP300, and Fs10+MANP600. Plasma aldosterone increased in furosemide groups, which was significantly attenuated in MANP+furosemide groups. Natriuresis and diuresis increased in all treated groups ( P <0.05) with no significant differences between furosemide and furosemide+MANP. In vitro, MANP increased cyclic guanosine monophosphate level in human vascular cells. Conclusions: We provide novel evidence that MANP potentiates the BP-lowering actions of furosemide, suppresses the activation of renin-angiotensin-aldosterone system, and preserves renal function. These data are highly relevant to clinical needs in the treatment of hypertension and heart failure.

Background Phosphodiesterase V (PDEV) is upregulated in heart failure, leading to increased degradation of cGMP and impaired natriuresis. PDEV inhibition improves the renal response to B‐type natriuretic peptide in animal models. We tested the hypothesis that long‐term PDEV inhibition would improve renal function and cardiorenal response after short‐term volume load in subjects with pre–heart failure. Methods and Results A total of 20 subjects with pre–heart failure (defined as an ejection fraction ≤45% without previous diagnosis of heart failure) and renal impairment were randomized in a 2:1 manner to tadalafil or placebo. Baseline echocardiography and renal clearance study were performed, followed by a short‐term saline load and repeated echocardiography and renal clearance study. Subjects then received either tadalafil at a goal dose of 20 mg daily or placebo, and the study day was repeated after 12 weeks. Long‐term tadalafil did not improve glomerular filtration rate (median increase of 2.0 mL/min in the tadalafil group versus 13.5 mL/min in the placebo group; P =0.54). There was no difference in urinary sodium or cGMP excretion with PDEV inhibition following short‐term saline loading. Conclusions Glomerular filtration rate and urinary sodium/cGMP excretion were not significantly different after 12 weeks of tadalafil compared with placebo. These results do not support the use of PDEV inhibition to improve renal response in patients with pre–heart failure. Registration URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01970176.