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Cardiovascular Research Apr 2024An increasing number of individuals are at high risk of type 2 diabetes (T2D) and its cardiovascular complications, including heart failure (HF), chronic kidney disease... (Review)
Review
An increasing number of individuals are at high risk of type 2 diabetes (T2D) and its cardiovascular complications, including heart failure (HF), chronic kidney disease (CKD), and eventually premature death. The sodium-glucose co-transporter-2 (SGLT2) protein sits in the proximal tubule of human nephrons to regulate glucose reabsorption and its inhibition by gliflozins represents the cornerstone of contemporary T2D and HF management. Herein, we aim to provide an updated overview of the pleiotropy of gliflozins, provide mechanistic insights and delineate related cardiovascular (CV) benefits. By discussing contemporary evidence obtained in preclinical models and landmark randomized controlled trials, we move from bench to bedside across the broad spectrum of cardio- and cerebrovascular diseases. With landmark randomized controlled trials confirming a reduction in major adverse CV events (MACE; composite endpoint of CV death, non-fatal myocardial infarction, and non-fatal stroke), SGLT2 inhibitors strongly mitigate the risk for heart failure hospitalization in diabetics and non-diabetics alike while conferring renoprotection in specific patient populations. Along four major pathophysiological axes (i.e. at systemic, vascular, cardiac, and renal levels), we provide insights into the key mechanisms that may underlie their beneficial effects, including gliflozins' role in the modulation of inflammation, oxidative stress, cellular energy metabolism, and housekeeping mechanisms. We also discuss how this drug class controls hyperglycaemia, ketogenesis, natriuresis, and hyperuricaemia, collectively contributing to their pleiotropic effects. Finally, evolving data in the setting of cerebrovascular diseases and arrhythmias are presented and potential implications for future research and clinical practice are comprehensively reviewed.
Topics: Humans; Sodium-Glucose Transporter 2 Inhibitors; Diabetes Mellitus, Type 2; Cardiovascular Diseases; Animals; Treatment Outcome; Blood Glucose; Sodium-Glucose Transporter 2; Risk Assessment; Risk Factors; Cardiovascular System; Biomarkers
PubMed: 38456601
DOI: 10.1093/cvr/cvae047 -
European Heart Journal Dec 2023Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of major heart failure events, an action that is statistically linked to enhanced erythropoiesis,...
Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of major heart failure events, an action that is statistically linked to enhanced erythropoiesis, suggesting that stimulation of erythropoietin and cardioprotection are related to a shared mechanism. Four hypotheses have been proposed to explain how these drugs increase erythropoietin production: (i) renal cortical reoxygenation with rejuvenation of erythropoietin-producing cells; (ii) counterregulatory distal sodium reabsorption leading to increased tubular workload and oxygen consumption, and thus, to localized hypoxia; (iii) increased iron mobilization as a stimulus of hypoxia-inducible factor-2α (HIF-2α)-mediated erythropoietin synthesis; and (iv) direct HIF-2α activation and enhanced erythropoietin gene transcription due to increased sirtuin-1 (SIRT1) signaling. The first two hypotheses assume that the source of increased erythropoietin is the interstitial fibroblast-like cells in the deep renal cortex. However, SGLT2 inhibitors do not alter regional tissue oxygen tension in the non-diabetic kidney, and renal erythropoietin synthesis is markedly impaired in patients with anemia due to chronic kidney disease, and yet, SGLT2 inhibitors produce an unattenuated erythrocytic response in these patients. This observation raises the possibility that the liver contributes to the production of erythropoietin during SGLT2 inhibition. Hypoxia-inducible factor-2α and erythropoietin are coexpressed not only in the kidney but also in hepatocytes; the liver is a major site of production when erythropoietin stimulation is maintained for prolonged periods. The ability of SGLT2 inhibitors to improve iron mobilization by derepressing hepcidin and ferritin would be expected to increase cytosolic ferrous iron, which might stimulate HIF-2α expression in both the kidney and liver through the action of iron regulatory protein 1. Alternatively, the established ability of SGLT2 inhibitors to enhance SIRT1 might be the mechanism of enhanced erythropoietin production with these drugs. In hepatic cell lines, SIRT1 can directly activate HIF-2α by deacetylation, and additionally, through an effect of SIRT in the liver, peroxisome proliferator-activated receptor-γ coactivator-1α binds to hepatic nuclear factor 4 to promote transcription of the erythropoietin gene and synthesis of erythropoietin. Since SIRT1 up-regulation exerts direct cytoprotective effects on the heart and stimulates erythropoietin, it is well-positioned to represent the shared mechanism that links erythropoiesis to cardioprotection during SGLT2 inhibition.
Topics: Humans; Sodium-Glucose Transporter 2; Sodium-Glucose Transporter 2 Inhibitors; Sirtuin 1; Kidney; Erythropoietin; Liver; Hypoxia; Basic Helix-Loop-Helix Transcription Factors; Glucose; Iron
PubMed: 37086098
DOI: 10.1093/eurheartj/ehad235 -
Aging Oct 2023Diabetic kidney disease (DKD) is a renal microvascular disease caused by hyperglycemia that involves metabolic remodeling, oxidative stress, inflammation, and other...
Analysis of potential biomarkers for diabetic kidney disease based on single-cell RNA-sequencing integrated with a single-cell sequencing assay for transposase-accessible chromatin.
Diabetic kidney disease (DKD) is a renal microvascular disease caused by hyperglycemia that involves metabolic remodeling, oxidative stress, inflammation, and other factors. The mechanism is complex and not fully unraveled. We performed an integrated single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq) and single-cell RNA-sequencing (scRNA-seq) analyses of kidneys from db/db and db/m mice to identify differential open chromatin regions and gene expression, particularly in genes related to proximal tubular reabsorption and secretion. We identified 9,776 differentially expressed genes (DEGs) and 884 cell type-specific transcription factors (TFs) across 15 cell types. Glucose and lipid transporters, and TFs related to the circadian rhythm in the proximal tubules had significantly higher expression in db/db mice than in db/m mice (<0.01). Crosstalk between podocytes and tubular cells in the proximal tubules was enhanced, and renal inflammation, oxidative stress, and fibrosis pathways were activated in db/db mice. Western blotting and immunohistochemical staining results showed that expression in the urine and kidneys of DKD patients was higher than that in non-diabetic kidney disease (NDKD) controls. The revealed landscape of chromatin accessibility and transcriptional profiles in db/db mice provide insights into the pathological mechanism of DKD.
Topics: Humans; Mice; Animals; Diabetic Nephropathies; Chromatin; RNA; Kidney; Biomarkers; Inflammation; Diabetes Mellitus; WAP Four-Disulfide Core Domain Protein 2
PubMed: 37827693
DOI: 10.18632/aging.205107 -
The FEBS Journal Apr 2024Acute kidney injury (AKI) induced by renal ischemia-reperfusion injury (IRI) has a high morbidity and mortality, representing a worldwide problem. The kidney is an... (Review)
Review
Acute kidney injury (AKI) induced by renal ischemia-reperfusion injury (IRI) has a high morbidity and mortality, representing a worldwide problem. The kidney is an essential organ of metabolism that has high blood perfusion and is the second most mitochondria-rich organ after the heart because of the high ATP demands of its essential functions of nutrient reabsorption, acid-base and electrolyte balance, and hemodynamics. Thus, these energy-intensive cells are particularly vulnerable to mitochondrial dysfunction. As the bulk of glomerular ultrafiltrate reabsorption by proximal tubules occurs via active transport, the mitochondria of proximal tubules must be equipped for detecting and responding to fluctuations in energy availability to guarantee efficient basal metabolism. Any insults to mitochondrial quality control mechanisms may lead to biological disruption, blocking the clearance of damaged mitochondria and resulting in morphological change and tissue dysfunction. Extensive research has shown that mitochondria have pivotal roles in acute kidney disease, so in this article, we discuss the role of mitochondria, their dynamics and mitophagy in renal ischemia-reperfusion injury.
PubMed: 38567754
DOI: 10.1111/febs.17130 -
Clinical Kidney Journal Oct 2023In chronic kidney disease (CKD) patients, hypofiltration may lead to the accumulation of drugs that are cleared mainly by the kidney and, vice versa, hyperfiltration may... (Review)
Review
In chronic kidney disease (CKD) patients, hypofiltration may lead to the accumulation of drugs that are cleared mainly by the kidney and, vice versa, hyperfiltration may cause augmented renal excretion of the same drugs. In this review we mainly focus on the issue of whether hyperfiltration significantly impacts the renal clearance of drugs and whether the same alteration may demand an up-titration of the doses applied in clinical practice. About half of severely ill, septic patients and patients with burns show glomerular hyperfiltration and this may lead to enhanced removal of drugs such as hydrophilic antibiotics and a higher risk of antibiotic treatment failure. In general, hyperfiltering obese individuals show higher absolute drug clearances than non-obese control subjects, but this depends on the body size descriptor adopted to adjust for fat excess. Several mechanisms influence pharmacokinetics in type 2 diabetes, including renal hyperfiltration, reduced tubular reabsorption and augmented tubular excretion. However, no consistent pharmacokinetic alteration has been identified in hyperfiltering obese subjects and type 2 diabetics. Non-vitamin K antagonist oral anticoagulants (NOACs) have exhibited lower plasma concentrations in hyperfiltering patients in some studies in patients with atrial fibrillation, but a recent systematic review failed to document any excess risk for stroke and systemic embolism in these patients. Hyperfiltration is common among severely ill patients in intensive care units and drug levels should be measured whenever possible in these high-risk patients to prevent underdosing and treatment failure. Hyperfiltration is also common in patients with obesity or type 2 diabetes, but no consistent pharmacokinetic alteration has been described in these patients. No NOAC dose adjustment is indicated in patients with atrial fibrillation being treated with these drugs.
PubMed: 37779850
DOI: 10.1093/ckj/sfad079 -
Current Opinion in Nephrology and... Sep 2023Regulation of the sodium chloride cotransporter (NCC) in the distal convoluted tubule (DCT) plays a crucial role in renal salt handling. The calcium-sensing receptor... (Review)
Review
PURPOSE OF REVIEW
Regulation of the sodium chloride cotransporter (NCC) in the distal convoluted tubule (DCT) plays a crucial role in renal salt handling. The calcium-sensing receptor (CaSR) has been shown to activate NCC through the WNK4-SPAK pathway, which is independent of the Renin-Angiotensin-Aldosterone system. In this review, we examine new information about the mechanism of how the CaSR regulates NCC through the WNK4-SPAK pathway and its physiological and therapeutic implications.
RECENT FINDINGS
The activation of CaSR in TALH cells during hypercalcemia inhibits NKCC2 and ROMK activity, reducing paracellular Ca2+ reabsorption but decreasing salt reabsorption. This pathway enables NaCl reabsorption in the DCT while promoting Ca2+ excretion. CaSR activation in the apical DCT stimulates a signaling pathway involving PKC, WNK4, and SPAK, which increases NCC activation to recover the NaCl not reabsorbed in TAHL. Glucose or fructose acting as calcimimetics enhance apical CaSR sensitivity, increasing NCC activity, which contribute to the mechanism of hypertension prevalence in diabetic patients or in those with high fructose consumption.
SUMMARY
These findings reveal the importance of the CaSR-mediated activation of the WNK4-SPAK pathway in regulating salt and calcium homeostasis and its potential as a therapeutic target for hypertension and related diseases.
Topics: Humans; Protein Serine-Threonine Kinases; Receptors, Calcium-Sensing; Phosphorylation; Sodium Chloride; Calcium; Kidney Tubules, Distal; Hypertension; Sodium Chloride, Dietary; Solute Carrier Family 12, Member 3
PubMed: 37530086
DOI: 10.1097/MNH.0000000000000915 -
Clinical Nutrition (Edinburgh, Scotland) Dec 2023Diabetes mellitus is a risk factor for muscle loss and sarcopenia. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) or "gliflozins" are one of the newest... (Review)
Review
Diabetes mellitus is a risk factor for muscle loss and sarcopenia. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) or "gliflozins" are one of the newest anti-hyperglycemic drugs. They reduce blood glucose levels by inhibiting renal glucose reabsorption in the early proximal convoluted tubule. Various randomized trials showed that SGLT2i have cardio-protective and reno-protective action. SGLT2i also affect body composition. They usually decrease body fat percentage, visceral and subcutaneous adipose tissue. However, regarding the muscle mass, there are conflicting findings some studies showing detrimental effects and others showed neutral or beneficial effects. This issue is extremely important not only because of the wide use of SGLT2i around globe; but also skeletal muscle mass consumes large amounts of calories during exercise and is an important determinant of resting metabolic rate and skeletal muscle loss hinders energy consumption leading to obesity. In this systematic review, we extensively reviewed the experimental and clinical studies regarding the impact of SGLT2i on muscle mass and related metabolic alterations. Importantly, studies are heterogeneous and there is unmet need to highlight the alterations in muscle during SGLT2i use.
Topics: Humans; Sodium-Glucose Transporter 2 Inhibitors; Diabetes Mellitus, Type 2; Sarcopenia; Glucose; Sodium; Symporters
PubMed: 37862820
DOI: 10.1016/j.clnu.2023.10.004 -
International Journal of Molecular... Sep 2023Chronic Kidney Disease (CKD) and Cardiovascular Disease (CVD) are two devastating diseases that may occur in nondiabetics or individuals with diabetes and, when... (Review)
Review
Chronic Kidney Disease (CKD) and Cardiovascular Disease (CVD) are two devastating diseases that may occur in nondiabetics or individuals with diabetes and, when combined, it is referred to as cardiorenal disease. The impact of cardiorenal disease on society, the economy and the healthcare system is enormous. Although there are numerous therapies for cardiorenal disease, one therapy showing a great deal of promise is sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors. The SGLT family member, SGLT2, is often implicated in the pathogenesis of a range of diseases, and the dysregulation of the activity of SGLT2 markedly effects the transport of glucose and sodium across the luminal membrane of renal cells. Inhibitors of SGLT2 were developed based on the antidiabetic action initiated by inhibiting renal glucose reabsorption, thereby increasing glucosuria. Of great medical significance, large-scale clinical trials utilizing a range of SGLT2 inhibitors have demonstrated both metabolic and biochemical benefits via numerous novel mechanisms, such as sympathoinhibition, which will be discussed in this review. In summary, SGLT2 inhibitors clearly exert cardio-renal protection in people with and without diabetes in both preclinical and clinical settings. This exciting class of inhibitors improve hyperglycemia, high blood pressure, hyperlipidemia and diabetic retinopathy via multiple mechanisms, of which many are yet to be elucidated.
Topics: Humans; Diabetes Mellitus, Type 2; Hypoglycemic Agents; Kidney; Sodium-Glucose Transporter 2; Sodium-Glucose Transporter 2 Inhibitors
PubMed: 37762542
DOI: 10.3390/ijms241814243 -
Clinical Chemistry and Laboratory... Nov 2023The ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate (TmP/GFR) is used to evaluate renal phosphate transport. TmP/GFR is most probably...
OBJECTIVES
The ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate (TmP/GFR) is used to evaluate renal phosphate transport. TmP/GFR is most probably calculated using the formula described by Kenny and Glen or obtained from the nomogram described by Walton and Bijvoet. Even though the calculation itself is well described, no attention has been given to its measurement uncertainty (MU). The aim of this study is to provide a procedure for evaluating the MU of the Kenny and Glen formula; a procedure which is based on the (GUM).
METHODS
TmP/GFR is a quantity value calculated from the input of measured values for serum (plasma) phosphate and creatinine, plus measured values of urine phosphate and creatinine. Given the measurement uncertainty associated with these input quantities, the GUM describes the mathematical procedures required to determine the uncertainty of the calculated TmP/GFR. From a medical laboratory perspective, these input uncertainties are the standard deviations of the respective internal quality control estimates for serum and urine phosphate, plus serum and urine creatinine.
RESULTS
Based on representative measurements for the input quantities and their associated standard uncertainties, the expanded relative uncertainty for a calculated TmP/GFR is approximately 3.0-4.5 %.
CONCLUSIONS
With the continued relevance of the TmP/GFR procedure and the use of creatinine clearance as an estimate of GFR, the addition of an uncertainty estimate is important as an adjunct to this diagnostic procedure.
Topics: Humans; Phosphates; Kidney Tubules; Creatinine; Uncertainty; Glomerular Filtration Rate
PubMed: 37462507
DOI: 10.1515/cclm-2023-0451