Antihypertensive treatment of end-stage renal disease patients on hemodialysis does not alter circulating ACE and ACE2 activity and angiotensin peptides.

Cardiovascular diseases (CVD) are the main causes of death in hemodialysis patients, representing a public health challenge. We investigated the effect of different antihypertensive treatments on circulating levels of renin-angiotensin system (RAS) components in end-stage renal disease (ESRD) patients on hemodialysis. ESRD patients were grouped following the prescribed antihypertensive drugs: ß-blocker, ß-blocker+ACEi and ß-blocker+AT1R blocker. ESDR patients under no antihypertensive drug treatment were used as controls. Blood samples were collected before hemodialysis sessions. Enzymatic activities of the angiotensin-converting enzymes ACE and ACE2 were measured through fluorescence assays and plasma concentrations of the peptides Angiotensin II (Ang II) and Angiotensin-(1-7) [Ang-(1-7)] were quantified using mass spectrometry (LC-MS/MS). ACE activity was decreased only in the ß-blocker+ACEi group compared to the ß-blocker+AT1R, while ACE2 activity did not change according to the antihypertensive treatment. Both Ang II and Ang-(1-7) levels also did not change according to the antihypertensive treatment. We concluded that the treatment of ESRD patients on hemodialysis with different antihypertensive drugs do not alter the circulating levels of RAS components.

Dietary Protein Restriction Improves Metabolic Dysfunction in Patients with Metabolic Syndrome in a Randomized, Controlled Trial.

Dietary restriction (DR) reduces adiposity and improves metabolism in patients with one or more symptoms of metabolic syndrome. Nonetheless, it remains elusive whether the benefits of DR in humans are mediated by calorie or nutrient restriction. This study was conducted to determine whether isocaloric dietary protein restriction is sufficient to confer the beneficial effects of dietary restriction in patients with metabolic syndrome. We performed a prospective, randomized controlled dietary intervention under constant nutritional and medical supervision. Twenty-one individuals diagnosed with metabolic syndrome were randomly assigned for caloric restriction (CR; n = 11, diet of 5941 ± 686 KJ per day) or isocaloric dietary protein restriction (PR; n = 10, diet of 8409 ± 2360 KJ per day) and followed for 27 days. Like CR, PR promoted weight loss due to a reduction in adiposity, which was associated with reductions in blood glucose, lipid levels, and blood pressure. More strikingly, both CR and PR improved insulin sensitivity by 62.3% and 93.2%, respectively, after treatment. Fecal microbiome diversity was not affected by the interventions. Adipose tissue bulk RNA-Seq data revealed minor changes elicited by the interventions. After PR, terms related to leukocyte proliferation were enriched among the upregulated genes. Protein restriction is sufficient to confer almost the same clinical outcomes as calorie restriction without the need for a reduction in calorie intake. The isocaloric characteristic of the PR intervention makes this approach a more attractive and less drastic dietary strategy in clinical settings and has more significant potential to be used as adjuvant therapy for people with metabolic syndrome.

Genetic deletion of the alamandine receptor MRGD leads to dilated cardiomyopathy in mice.

We have recently described a new peptide of the renin-angiotensin system, alamandine, a derivative of angiotensin-(1-7). Mas-related G protein-coupled receptor member D (MrgD) was identified as its receptor. Although similar cardioprotective effects of alamandine to those of angiotensin-(1-7) have been described, the significance of this peptide in heart function is still elusive. We aimed to evaluate the functional role of the alamandine receptor MrgD in the heart using MrgD-deficient mice. MrgD was localized in cardiomyocytes by immunofluorescence using confocal microscopy. High-resolution echocardiography was performed in wild-type and MrgD-deficient mice (2 and 12 wk old) under isoflurane anesthesia. Standard B-mode images were obtained in the right and left parasternal long and short axes for morphological and functional assessment and evaluation of cardiac deformation. Additional heart function evaluation was performed using Langendorff isolated heart preparations and inotropic measurements of isolated cardiomyocytes. Immunofluorescence indicated that the MrgD receptor is expressed in cardiomyocytes, mainly in the membrane and perinuclear and nuclear regions. Echocardiography showed left ventricular remodeling and severe dysfunction in MrgD-deficient mice. Strikingly, MrgD-deficient mice presented a pronounced dilated cardiomyopathy with a marked decrease in systolic function. Echocardiographic changes were supported by the data obtained in isolated hearts and inotropic measurements in cardiomyocytes. Our data add new evidence for a major role for alamandine/MrgD in the heart. Furthermore, our results indicate that we have identified a new gene implicated in dilated cardiomyopathy, unveiling a new target for translational approaches aimed to treat heart diseases. NEW & NOTEWORTHY The renin-angiotensin system is a key target for cardiovascular therapy. We have recently identified a new vasodepressor/cardioprotective angiotensin, alamandine. Here, we unmasked a key role for its receptor, Mas-related G protein-coupled receptor member D (MrgD), in heart function. The severe dilated cardiomyopathy observed in MrgD-deficient mice warrants clinical and preclinical studies to unveil its potential use in cardiovascular therapy.