Adrenergic activation, fuel substrate availability, and insulin resistance in patients with congestive heart failure

Reverse Remodeling Effects of Sacubitril-Valsartan: Structural and Functional Optimization in Stage C Heart Failure

Sacubitril-valsartan, an angiotensin receptor-neprilysin inhibitor, reduces all-cause mortality and the rate of heart failure hospitalizations in patients with heart failure with reduced ejection fraction. This study aimed to elucidate the benefits of initiating sacubitril-valsartan on ventricular remodeling in patients previously optimized on guideline-directed medical therapy. In this prospective, single-arm longitudinal study, 40 patients with heart failure with reduced ejection fraction who were optimized on guideline-directed medical therapy were transitioned to sacubitril-valsartan. The primary end point was the change in left ventricular (LV) volume at 1 year as assessed by 3-dimensional transthoracic echocardiography. Other echocardiographic end points included change in LV-function and change in right ventricular (RV) size and function. The mean age was 55 ± 12 years, and 63% were male. At 1 year, LV end-diastolic volume decreased from 242 ± 71 to 157 ± 57 ml (p <0.001) with a corresponding increase in LV ejection fraction from 32 ± 7% to 44 ± 9% (p <0.001). RV end-diastolic volume decreased from 151 ± 51 to 105 ±45 ml (p <0.001). Although RV ejection fraction did not change (51 ± 8 vs 51 ± 10; p = 0.35), RV global longitudinal strain improved from -14.9 ± 3.4 % to -19.3 ± 4.3% (p <0.001). When added to standard medical therapy for heart failure, sacubitril-valsartan induces significant remodeling of both the right and left ventricles as assessed by 3-dimensional echocardiography.

Long-Term Weight Gain Associated With High Omentin Levels at Hospital Discharge Improves Prognosis of Patients Following Acute Heart Failure

A obesity paradox has been described following heart failure (HF). The aim of this study was to analyze the association between food intake-involved adipokines and long-term weight changes. Leptin, adiponectin, and omentin were analyzed in 92 acute HF (AHF) patients at discharge, classified on the basis of weight gains or losses > 6%. The mean follow-up was 256 ± 143 days. Leptin and adiponectin levels were similar among weight groups. However, omentin levels were higher in those patients who had gained weight (16 ± 5 ng/mL) than in those who had lost weight (12 ± 4 ng/mL) or showed no weight change (11 ± 5 ng/mL; p < 0.002). Omentin levels were the best independent predictors for patients with weight gain, who had less mortality and hospital readmission during the follow-up. The association between omentin levels and weight gain might explain part of the obesity paradox in HF.

Predisposing factors to heart failure in diabetic nephropathy: a look at the sympathetic nervous system hyperactivity

Diabetes mellitus (DM) and heart failure (HF) are frequent comorbidities among elderly patients. HF, a leading cause of mortality and morbidity worldwide, is characterized by sympathetic nervous system hyperactivity. The prevalence of diabetes mellitus (DM) is rapidly growing and the risk of developing HF is higher among DM patients. DM is responsible for several macro- and micro-angiopathies that contribute to the development of coronary artery disease (CAD), peripheral artery disease, retinopathy, neuropathy and diabetic nephropathy (DN) as well. Independently of CAD, chronic kidney disease (CKD) and DM increase the risk of HF. Individuals with diabetic nephropathy are likely to present a distinct pathological condition, defined as diabetic cardiomyopathy, even in the absence of hypertension or CAD, whose pathogenesis is only partially known. However, several hypotheses have been proposed to explain the mechanism of diabetic cardiomyopathy: increased oxidative stress, altered substrate metabolism, mitochondrial dysfunction, activation of renin-angiotensin-aldosterone system (RAAS), insulin resistance, and autonomic dysfunction. In this review, we will focus on the involvement of sympathetic system hyperactivity in the diabetic nephropathy.

The Modulating Effects of Cardiac Resynchronization Therapy on Myocardial Metabolism in Heart Failure

Heart failure (HF) is associated with changes in cardiac substrate utilization and energy metabolism, including a decline in high-energy phosphate content, mitochondrial dysfunction, and phosphotransfer enzyme deficiency. A shift toward glucose metabolism was noted in the end stage of HF in animals, although HF in humans may not be associated with a shift toward predominant glucose utilization. Deficiencies of micronutrients are well-established causes of cardiomyopathy. Correction of these deficits can improve heart function. The genes governing the energy metabolism were predominantly underexpressed in nonischemic cardiomyopathy and hypertrophic cardiomyopathy but were overexpressed in ischemic cardiomyopathy. Cardiac resynchronization therapy (CRT) has been proven to increase cardiac efficiency without increasing myocardial oxygen consumption. Altered myocardial metabolism is normalized by CRT to improve ventricular function.

Retinol-Binding Protein 4 Induces Cardiomyocyte Hypertrophy by Activating TLR4/MyD88 Pathway

Insulin resistance plays a major role in the development and progression of cardiac hypertrophy and heart failure. Heart failure in turn promotes insulin resistance and increases the risk for diabetes. The vicious cycle determines significant mortality in patients with heart failure and diabetes. However, the underlying mechanisms for the vicious cycle are not fully elucidated. Here we show that circulating levels and adipose expression of retinol-binding protein 4 (RBP4), an adipokine that contributes to systemic insulin resistance, were elevated in cardiac hypertrophy induced by transverse aortic constriction and angiotensin-II (Ang-II) infusion. Ang-II increased RBP4 expression in adipocytes, which was abolished by losartan, an Ang-II receptor blocker. The elevated RBP4 in cardiac hypertrophy may have pathophysiological consequences because RBP4 increased cell size, enhanced protein synthesis, and elevated the expression of hypertrophic markers including Anp, Bnp, and Myh7 in primary cardiomyocytes. Mechanistically, RBP4 induced the expression and activity of toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) in cardiomyocytes, resulting in enhanced inflammation and reactive oxygen species production. Inhibition or knockdown of the TLR4/MyD88 pathway attenuated inflammatory and hypertrophic responses to RBP4 stimulation. Importantly, RBP4 also reduced the expression of glucose transporter-4 and impaired insulin-stimulated glucose uptake in cardiomyocytes. This impairment was ameliorated in cardiomyocytes from TLR4 knockout mice. Therefore, RBP4 may be a critical modulator promoting the vicious cycle of insulin resistance and heart failure by activating TLR4/MyD88-mediated inflammatory pathways. Potentially, lowering RBP4 might break the vicious cycle and improve both insulin resistance and cardiac hypertrophy.

Impact of diabetes mellitus on lymphocyte GRK2 protein levels in patients with heart failure

BACKGROUND

Diabetes mellitus (DM) is associated with impaired prognosis in patients with heart failure (HF), but pathogenic mechanisms are unclear. In the failing heart, elevated β-adrenergic receptor (β-AR) activation by catecholamines causes G-protein-coupled receptor kinase-2 (GRK2) upregulation which is responsible for β-AR signalling dysfunction. Importantly, GRK2 expression, measured in peripheral lymphocytes of HF patients, correlates with levels of this kinase in the failing myocardium reflecting the loss of hemodynamic function. Moreover, HF-related GRK2 protein overexpression promotes insulin resistance by interfering with insulin signalling. The aim of this study was to assess lymphocyte GRK2 protein levels in HF patients with and without DM.

METHODS AND MATERIALS

Patients with a diagnosis of HF were enrolled in the study. All subjects underwent a complete clinical examination (including NYHA functional class assessment and echocardiography) and blood draw for serum N-terminal pro-brain natriuretic peptide (NT-proBNP), lymphocyte GRK2 and plasma norepinephrine (NE) levels. Demographic data including age, sex, medications, cardiovascular risk factors and presence of comorbidities were also collected.

RESULTS

Two hundred and sixty-eight patients with HF (left ventricular ejection fraction [LVEF] 30.6 ± 7.6%) with and without DM were enrolled. No differences between the two groups were found in terms of demography, HF aetiology, LVEF, NYHA class, NE and NT-proBNP. GRK2 was significantly higher in patients with DM compared to non-DM. At multivariate linear regression analysis, LVEF, NE, NT-proBNP and diabetes came out to be independent predictors of GRK2 levels in the overall study population.

CONCLUSION

In HF patients, DM is associated with significantly more elevated lymphocyte GRK2 protein levels, likely reflecting more compromised cardiac β-AR signalling/function, despite similar hemodynamic status and neuro-hormonal activation compared to patients without DM. These findings contribute to explain the negative prognostic impact of DM in patients with HF.

Impact of diabetes mellitus on the clinical response to cardiac resynchronization therapy in elderly people

Heart failure (HF) and type 2 diabetes mellitus (T2DM) exhibit a well-established interrelationship and a growing prevalence, in particular in elderly people. Cardiac resynchronization therapy (CRT) has been shown to improve myocardial function in patients with HF and cardiac dyssynchrony. However, reports on CRT in diabetic elderly patients are limited and controversial. Therefore, the aim of the present study was to investigate the functional role of T2DM on the effectiveness of CRT at advanced age. In this single-center prospective study, we enrolled 72 HF patients over 75 years old with and without T2DM who underwent CRT implant. Detailed clinical and instrumental data, including cardiac ultrasound analysis, 6-min walk test, and quality-of-life evaluation, were collected at baseline and at 1-year follow-up. At the time of implantation, 44.4 % of patients had T2DM, of which 62.5 % were well controlled with diet and hypoglycemic drugs and 37.5 % were treated by insulin therapy. After 1 year, CRT improved myocardial ventricular geometry and functional capacity in a comparable proportion of diabetic and non-diabetic patients alongside with a similar amelioration in the functional status. Taken together, our findings demonstrate that diabetic patients >75 years old exhibit a response to CRT that is comparable to non-diabetic subjects.