Effect of diuretics on plasma aldosterone and potassium in primary hypertension: A systematic review and meta-analysis

Ischaemic Cardiomyopathy Secondary to Asymptomatic Coronary Artery Disease: A Case Report

Ischaemic cardiomyopathy (ICM) represents a common complication of coronary artery disease (CAD). Ischaemia causes ventricular remodelling, leading to an irreversible loss of myocardial tissue and adequate contractility, primarily affecting the left ventricular ejection fraction (LVEF). We present the case of a 46-year-old male known as hypertensive presented to the hospital with a five-week history of progressive exertional dyspnoea, bilateral lower limb oedema subsequently involving his scrotum and penis. He reported reduced oral intake and occasional palpitations but denied chest pain, cough, fever, or haemoptysis. He had no personal history of cardiac disease, recent travels, or recreational drug use. Notably, he consumed approximately 12 units of alcohol weekly and was a non-smoker. On admission, he was treated for new-onset heart failure, and initial investigations showed acute kidney injury, raised troponin, and brain natriuretic peptide (BNP), and chest X-ray showed an enlarged heart size (cardiothoracic ratio (CTR), 0.56) with moderate right pleural effusion. Echocardiography revealed a severely dilated left ventricle with severely impaired systolic function (LVEF 16%), bi-atrial dilatation, borderline dilated right ventricle with impaired systolic function, and moderate tricuspid regurgitation. Cardiac MRI showed that the left ventricle was severely dilated with severely impaired systolic function with nonviable mid to apical inferior and inferoseptal transmural post-ischaemic scar with associated hypokinesia. Ischaemic cardiomyopathy may vary from asymptomatic to severely symptomatic, commonly when symptomatic patients will present with anginal chest pain and dyspnoea on exertion. In contrast, asymptomatic patients can sometimes have up to 80% of transient ischaemic events with no chest pain or associated symptoms. This case underscores the importance of considering asymptomatic coronary artery disease in clinical practice and highlights the need for novel interventions and markers for early ischemia detection.

Esaxerenone Attenuates Aldosterone-Induced Mitochondrial Damage-Mediated Pyroptosis in Mouse Aorta and Rat Vascular Smooth Muscle Cells

BACKGROUND

Vascular smooth muscle cell (VSMC) injury caused by the inflammatory response plays a key role in cardiovascular disease (CVD), and the vasoprotective effects of mineralocorticoid receptor blockers (MRBs) support the role of mineralocorticoid receptor (MR) activation.

METHODS

C57BL/6 mice and VSMCs isolated from rats were treated with aldosterone and esaxerenone. Caspase-1, GSDMD-N, IL-1β, and NR3C2 expression and DNA damage in aortic VSMCs were detected using immunohistochemistry, Western blotting, and TUNEL staining. Mitochondrial changes were detected by transmission electron microscopy (TEM). Reactive oxygen species (ROS), MitoTracker, JC-I, mitochondrial respiratory chain complexes I-V, and NR3C2 were detected using immunofluorescence and flow cytometry. Pyroptosis was detected with scanning electron microscopy (SEM).

RESULTS

After aldosterone treatment, the number of TUNEL-positive cells increased significantly, and the expression of caspase-1, GSDMD-N, and IL-1β increased. TEM revealed mitochondrial damage, and SEM revealed specific pyroptotic changes, such as cell membrane pore changes and cytoplasmic extravasation. Increased ROS levels and nuclear translocation of NR3C2 were also observed. These pyroptosis-related changes were reversed by esaxerenone.

CONCLUSIONS

Aldosterone activates the MR and mediates mitochondrial damage, thereby inducing pyroptosis in VSMCs via the NLRP3/caspase-1 pathway. Esaxerenone inhibits MR activation and reduces mitochondrial damage and oxidative stress, thereby inhibiting pyroptosis.

SGLT2 inhibition effect on salt-induced hypertension, RAAS, and Na+ transport in Dahl SS rats

Na+-glucose cotransporter-2 (SGLT2) inhibitors are the new mainstay of treatment for diabetes mellitus and cardiovascular diseases. Despite the remarkable benefits, the molecular mechanisms mediating the effects of SGLT2 inhibitors on water and electrolyte balance are incompletely understood. The goal of this study was to determine whether SGLT2 inhibition alters blood pressure and kidney function via affecting the renin-angiotensin-aldosterone system (RAAS) and Na+ channels/transporters along the nephron in Dahl salt-sensitive rats, a model of salt-induced hypertension. Administration of dapagliflozin (Dapa) at 2 mg/kg/day via drinking water for 3 wk blunted the development of salt-induced hypertension as evidenced by lower blood pressure and a left shift of the pressure natriuresis curve. Urinary flow rate, glucose excretion, and Na+- and Cl--to-creatinine ratios increased in Dapa-treated compared with vehicle-treated rats. To define the contribution of the RAAS, we measured various hormones. Despite apparent effects on Na+- and Cl--to-creatinine ratios, Dapa treatment did not affect RAAS metabolites. Subsequently, we assessed the effects of Dapa on renal Na+ channels and transporters using RT-PCR, Western blot analysis, and patch clamp. Neither mRNA nor protein expression levels of renal transporters (SGLT2, Na+/H+ exchanger isoform 3, Na+-K+-2Cl- cotransporter 2, Na+-Cl- cotransporter, and α-, β-, and γ-epithelial Na+ channel subunits) changed significantly between groups. Furthermore, electrophysiological experiments did not reveal any difference in Dapa treatment on the conductance and activity of epithelial Na+ channels. Our data suggest that SGLT2 inhibition in a nondiabetic model of salt-sensitive hypertension blunts the development of salt-induced hypertension by causing glucosuria and natriuresis without changes in the RAAS or the expression or activity of the main Na+ channels and transporters.NEW & NOTEWORTHY The present study indicates that Na+-glucose cotransporter-2 (SGLT2) inhibition in a nondiabetic model of salt-sensitive hypertension blunts the development and magnitude of salt-induced hypertension. Chronic inhibition of SGLT2 increases glucose and Na+ excretion without secondary effects on the expression and function of other Na+ transporters and channels along the nephron and hormone levels in the renin-angiotensin-aldosterone system. These data provide novel insights into the effects of SGLT2 inhibitors and their potential use in hypertension.