Increased levels of glucagon in type 2 diabetes are well known and, until now, have been considered deleterious. However, glucagon has an important role in the maintenance of both heart and kidney ...function. Moreover, in the past, glucagon has been therapeutically used for heart failure treatment. The new antidiabetic drugs, dipeptidyl peptidase-4 inhibitors and sodium-glucose co-transporter-2 inhibitors, are able to decrease and to increase glucagon levels, respectively, while contrasting data have been reported regarding the glucagon like peptide 1 receptors agonists. The cardiovascular outcome trials, requested by the FDA, raised some concerns about the possibility that the dipeptidyl peptidase-4 inhibitors can precipitate the heart failure, while, at least for empagliflozin, a positive effect has been shown in decreasing both cardiovascular death and heart failure. The recent LEADER Trial, showed a significant reduction of cardiovascular death with liraglutide, but a neutral effect on heart failure. A possible explanation of the results with the DPPIV inhibitors and empagliflozin might be related to their divergent effect on glucagon levels. Due to unclear effects of glucagon like peptide 1 receptor agonists on glucagon, the possible role of this hormone in the Leader trial remains unclear.
Heart failure is associated with a range of comorbidities that have the potential to impair both quality of life and clinical outcome. Unfortunately, noncardiac diseases are underrepresented in large ...randomized clinical trials, and their management remains poorly understood. In clinical practice, the prevalence of comorbidities in heart failure is high. Although the prognostic impact of comorbidities is well known, their prevalence and impact in specific heart failure settings have been overlooked. Many studies have described specific single noncardiac conditions, but few have examined their overall burden and grading in patients with multiple comorbidities. The risk of comorbidities in patients with heart failure rises with more advanced disease, older age, and increased frailty—three conditions that are poorly represented in clinical trials. The pathogenic links between comorbidities and heart failure involve many pathways and include neurohormonal overdrive, inflammatory activation, oxidative stress, and endothelial dysfunction. Such interactions may worsen prognoses, but details of these relationships are still under investigation. We propose a shift from cardiac-focused care to a more systemic approach that considers all noncardiac diseases and related medications. Some new drugs class such as ARNI or SGLT2 inhibitors could change prognosis by acting directly or indirectly on metabolic disorders and related vascular consequences.
The liver is not the exclusive site of glucose production in humans in the postabsorptive state. Robust data support that the kidney is capable of gluconeogenesis and studies have demonstrated that ...renal glucose production can increase systemic glucose production. The kidney has a role in maintaining glucose body balance, not only as an organ for gluconeogenesis but by using glucose as a metabolic substrate. The kidneys reabsorb filtered glucose through the sodium-glucose cotransporters sodium-glucose cotransporter (SGLT) 1 and SGLT2, which are localized on the brush border membrane of the early proximal tubule with immune detection of their expression in the tubularized Bowman capsule. In patients with diabetes mellitus, the renal maximum glucose reabsorptive capacity, and the threshold for glucose passage into the urine, are higher and contribute to the hyperglycemic state. The administration of SGLT2 inhibitors to patients with diabetes mellitus enhances sodium and glucose excretion, leading to a reduction of the glycosuria threshold and tubular maximal transport of glucose. The net effects of SGLT2 inhibition are to drive a reduction in plasma glucose levels, improving insulin secretion and sensitivity. The benefit of SGLT2 inhibitors goes beyond glycemic control, since inhibition of renal glucose reabsorption affects blood pressure and improves the hemodynamic profile and the tubule glomerular feedback. This action acts to rebalance the dense macula response by restoring adenosine production and restraining renin-angiotensin-aldosterone activation. By improving renal and cardiovascular function, we explain the impressive reduction in adverse outcomes associated with heart failure supporting the current clinical perspective.
In the essential homeostatic role of kidney, two intrarenal mechanisms are prominent: the glomerulotubular balance driving the process of Na+ and water reabsorption in the proximal tubule, and the ...tubuloglomerular feedback which senses the Na+ concentration in the filtrate by the juxtaglomerular apparatus to provide negative feedback on the glomerular filtration rate. In essence, the two mechanisms regulate renal oxygen consumption. The renal hyperfiltration driven by increased glomerular filtration pressure and by glucose diuresis can affect renal O2 consumption that unleashes detrimental sympathetic activation. The sodium-glucose co-transporters inhibitors (SGLTi) can rebalance the reabsorption of Na+ coupled with glucose and can restore renal O2 demand, diminishing neuroendocrine activation. Large randomized controlled studies performed in diabetic subjects, in heart failure, and in populations with chronic kidney disease with and without diabetes, concordantly address effective action on heart failure exacerbations and renal adverse outcomes.
The kidneys and heart work together to balance the body's circulation, and although their physiology is based on strict inter dependence, their performance fulfills different aims. While the heart ...can rapidly increase its own oxygen consumption to comply with the wide changes in metabolic demand linked to body function, the kidneys physiology are primarily designed to maintain a stable metabolic rate and have a limited capacity to cope with any steep increase in renal metabolism. In the kidneys, glomerular population filters a large amount of blood and the tubular system has been programmed to reabsorb 99% of filtrate by reabsorbing sodium together with other filtered substances, including all glucose molecules. Glucose reabsorption involves the sodium-glucose cotransporters SGLT2 and SGLT1 on the apical membrane in the proximal tubular section; it also enhances bicarbonate formation so as to preserve the acid-base balance. The complex work of reabsorption in the kidney is the main factor in renal oxygen consumption; analysis of the renal glucose transport in disease states provides a better understanding of the renal physiology changes that occur when clinical conditions alter the neurohormonal response leading to an increase in glomerular filtration pressure. In this circumstance, glomerular hyperfiltration occurs, imposing a higher metabolic demand on kidney physiology and causing progressive renal impairment. Albumin urination is the warning signal of renal engagement over exertion and most frequently heralds heart failure development, regardless of disease etiology. The review analyzes the mechanisms linked to renal oxygen consumption, focusing on sodium-glucose management.
Ischemic heart disease and non-ischemic dilated cardiomyopathy are the most common causes of arrhythmic sudden cardiac death (SCD). Implantable cardioverter defibrillator (ICD) therapy is the only ...strategy that proved to be effective in preventing SCD in high-risk individuals while the role of antiarrhythmic drugs is limited to symptoms relief. Current guidelines recommend selecting candidates to ICD implantation based on etiology, symptoms of heart failure (NYHA class), and severely depressed left ventricular ejection fraction, but these parameters are neither sensitive nor specific. The review addresses the mechanisms of SCD in patients with heart failure of either ischemic or non-ischemic etiology, risk stratification, and strategies for prevention of SCD in the clinical practice (including optimization of heart failure therapy, avoidance of triggering factors, antiarrhythmic drugs, ICD therapy, early resuscitation, and public access defibrillators).
Transition from stage C to stage D of heart failure (HF) represents an irreversible process toward end-stage disease. Crucial interventions to be adopted in the attempt to interfere with this process ...are represented by the identification of patients at high risk to develop HF progression and by an effective and prompt management. Markers of worse prognosis and disease progression are well established and include recurrence of HF decompensation, intolerance to the neurohormonal standard pharmacological treatment, and resistance to loop diuretics. In addition, both NT-proBNP and sympathetic nervous system (SNS) overdrive are strong predictors of adverse clinical outcome and allow to identify high-risk HF patients even in the presence of mild symptoms. To counteract the deleterious effects of the SNS activation, new strategies such as a new drug combining angiotensin receptor and neprilysin inhibition and baroreceptor stimulation therapy (BAT) have been investigated. Inability to properly counteract the SNS overdrive leads to acute HF decompensation by different mechanisms. The leading ones are represented by the progressive sodium and water retention with fluid overload and by the blood volume redistribution between splanchnic and non-splanchnic regions. The correct understanding of these mechanisms, together with the availability of new therapeutic options such as peritoneal ultrafiltration, represent the rationale but not infrequently overlooked therapeutic options to improve congestion management in HF patients.
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