SGLT2 Inhibition Mediates Protection from Diabetic Kidney Disease by Promoting Ketone Body-Induced mTORC1 Inhibition

Dapagliflozin improves diabetic kidney disease by inhibiting ferroptosis through β-hydroxybutyrate production

BACKGROUND

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2i) are antihyperglycemic agents that provide additional renal-protective effects in patients with DKD, independent of their glucose-lowering effects. However, the underlying mechanism remains unclear. This study hypothesized that SGLT2i could alleviate diabetic kidney injury by inhibiting ferroptosis and explored its potential mechanisms.

METHODS

C57BL/6J mice were randomly divided into the control, DKD, DKD+dapagliflozin, and DKD+insulin treatment groups. Blood glucose levels and body weight were monitored. Renal function, tissue pathology, mitochondrial morphology and function, and lipid peroxidation biomarkers (lipid peroxidation [LPO], malondialdehyde [MDA], glutathione peroxidase 4 [GPX4], glutathione [GSH], and cystine transporter solute carrier family 7 member 11 [SLC7A11]) were evaluated. Human proximal tubule cells (HK2 cells) were exposed to high glucose alone or in combination with dapagliflozin. The mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) level, NAD+/NADH ratio (oxidized/reduced ratio of nicotinamide adenine dinucleotide), and lipid peroxidation were measured. In addition, the role of the β-hydroxybutyrate- Calcium/Calmodulin Dependent Protein Kinase Kinase 2 (BHB-CaMKK2) axis in mediating dapagliflozin regulating ferroptosis was examined.

RESULTS

Dapagliflozin significantly ameliorated kidney injury in mice with DKD. Typical changes in ferroptosis, including lipid peroxidation and impaired antioxidant capacity, increased in mice with DKD and HG-treated HK-2 cells. Dapagliflozin significantly improves ferroptosis-related lipid peroxidation and mitochondrial dysfunction. Furthermore, dapagliflozin suppressed the expression of CaMKK2, a key ferroptosis regulator. Specific CaMKK2 inhibitors alleviated mitochondrial damage and ferroptosis, whereas a CaMKK2 agonist counteracted the protective effects of dapagliflozin against mitochondrial, antioxidant, and anti-ferroptosis effects. In addition, dapagliflozin increased BHB production, which mediates its nephroprotective effects.

CONCLUSION

Dapagliflozin improves DKD by inhibiting ferroptosis, promoting BHB production, and regulating CaMKK2.

SGLT2 inhibitors use in kidney disease: what did we learn?

Chronic kidney disease (CKD) increases the risk for cardiovascular morbidity and mortality and it's prevalence continues to rise throughout the world. Newer, more efficacious therapies, slow progression of CKD, decrease long-term sequela like end-stage kidney disease (ESKD) and cardiovascular events, improving survival. Postmarketing cardiovascular outcome trials (CVOT) have demonstrated improved cardiovascular outcomes with the use of sodium-glucose cotransporter-2 inhibitors (SGLT2i) like canagliflozin, dapagliflozin, empagliflozin, ertugliflozin, and sotagliflozin in patients with type 2 diabetes mellitus (T2DM), Similarly, secondary analysis of CVOT and renal outcome trials with the use of SGLT2i in patients without T2DM showed improved renal function and albuminuria. In these studies, nondiabetic CKD was defined as an estimated glomerular filtration rate (eGFR) of 20-75 mL/min/1.73 m2 with albuminuria ranging from 200 to 5,000 mg/g in the absence of diabetes. As a class effect, in addition to modulation of hemodynamic and metabolic activities, SGLT2i exert renal protection by suppressing inflammation and fibrosis. We conducted an extensive search in the PubMed database for original papers published from 2009 through 2024 using keywords such as nondiabetic kidney disease, diabetic kidney disease, SGLT2i, and kidney outcomes. Based on our research of published literature, we present a review and propose, consideration of SGLT2i in nondiabetic kidney disease for long-term cardiovascular and renal benefit (Dharia A, Khan A, Sridhar VS, Cherney DZI. Annu Rev Med 74: 369-384, 2023). We will highlight relevant translational studies to propose a possible cell-based mechanism for cardiovascular benefits noted secondary to use of SGLT2i.

Unveiling the Anti-Aging Potential of 3HB: Lifespan Extension and Cellular Senescence Delay

BACKGROUND/OBJECTIVE

Aging is a significant risk factor for chronic diseases and disability, yet effective anti-aging interventions remain elusive. We explored the potential of 3-hydroxybutyrate (3HB), an endogenous metabolite with established safety, to modulate longevity in mice.

METHODS

In this study, we employed 2BS and WI-38 cell models, a yeast model, and naturally aging mouse models to investigate the effects of 3HB on aging in various systems. Additionally, we utilized RNA sequencing and metabolomics technologies to explore the potential mechanisms underlying the action of 3HB.

RESULTS

Our findings demonstrate that 3HB supplementation effectively delays cellular senescence, extending yeast lifespan by 51.3% and the median lifespan of naturally senescent mice by 21.0%. Notably, 3HB prolonged healthy lifespan in mice while mitigating age-related tissue morphology changes and organ senescence. Mechanistically, we identified that 3HB's anti-aging properties are mediated through its ability to delay cellular senescence and metabolic reprogramming, while promoting the production of beneficial metabolites like trigoneline and isoguvacine.

CONCLUSIONS

These findings highlight the promising therapeutic potential of 3HB as an anti-aging intervention and provide novel insights into its underlying mechanisms.

SGLT2 inhibitors as a novel senotherapeutic approach

Cellular senescence is the permanent cessation of cell proliferation and growth. Senescent cells accumulating in tissues and organs with aging contribute to many chronic diseases, mainly through the secretion of a pro-inflammatory senescence-associated secretory phenotype (SASP). Senotherapeutic (senolytic or senomorphic) strategies targeting senescent cells or/and their SASP are being developed to prolong healthy lifespan and treat age-related pathologies. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new class of anti-diabetic drugs that promote the renal excretion of glucose, resulting in lower blood glucose levels. Beyond their glucose-lowering effects, SGLT2 inhibitors have demonstrated protective effects against cardiovascular and renal events. Moreover, SGLT2 inhibitors have recently been associated with the inhibition of cell senescence, making them a promising therapeutic approach for targeting senescence and aging. This review examines the latest research on the senotherapeutic potential of SGLT2 inhibitors.

Associated factors and principal pathophysiological mechanisms of type 2 diabetes mellitus

Type 2 diabetes mellitus(T2DM) as a common chronic disease with an increasing prevalence worldwide that poses a great threat to individual health, and is characterized by chronic hyperglycemia resulting from insulin resistance (IR) coupled with β-cell dysfunction. Mitochondrial dysfunction, obesity, gut microbiota, oxidative stress and inflammation have emerged as a significant contributor to the etiology of T2DM, affecting various metabolic processes critical for glucose homeostasis. This short review underscores their role in enhancing T2DM-related molecular mechanisms and explores recent advancements in diabetic management, further highlights the importance of personalized care plans to address the complexities of the T2DM and aims to improve patient quality of life and long-term health outcome.

Sodium-Glucose Cotransporter 2 Inhibitors in Aortic Stenosis: Toward a Comprehensive Cardiometabolic Approach

Aortic stenosis (AS), the most prevalent valvular heart disease, is increasingly recognized as an active disease process driven by a convergence of hemodynamic stress, inflammation, oxidative injury, and metabolic remodeling. While transcatheter and surgical valve replacement remain the standard interventions for severe AS, they fail to reverse the chronic myocardial remodeling that underlies adverse outcomes in many patients. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as promising cardioprotective agents, with effects extending well beyond glycemic control. Recent mechanistic studies reveal that SGLT2 is expressed in the myocardium of patients with AS and is linked to pathways of fibrosis, inflammation, and energetic dysfunction. Experimental models and translational data demonstrate that SGLT2 inhibition attenuates maladaptive remodeling through modulation of TGF-β, NF-κB, NLRP3 inflammasome, and oxidative stress signaling while enhancing mitochondrial energetics and endothelial function. Importantly, clinical evidence from randomized and real-world studies suggests that SGLT2 inhibitors improve heart failure outcomes following valve replacement and may slow AS progression. This review integrates current pathophysiological insights with emerging molecular and clinical data to delineate the therapeutic rationale for SGLT2 inhibition in AS. By targeting both myocardial and valvular components of the disease, SGLT2 inhibitors may offer a novel disease-modifying strategy with potential implications across the AS continuum-from asymptomatic stages to the post-interventional setting. Ongoing and future trials are warranted to define optimal patient selection, timing, and biomarkers for response to SGLT2 inhibitor therapy in this increasingly high-risk population.

Impaired ketogenesis in Leydig Cells drives testicular aging

Testicular aging commonly leads to testosterone deficiency and impaired spermatogenesis, yet the underlying mechanisms remain elusive. Here, we show that Leydig cells are particularly vulnerable to aging processes in testis. Single-cell RNA sequencing identifies the expression of Hmgcs2, the gene encoding rate-limiting enzyme of ketogenesis, decreases significantly in Leydig cells from aged mice. Additionally, the concentrations of ketone bodies β-hydroxybutyric acid and acetoacetic acid in young testes are substantially higher than that in serum, but significantly diminish in aged testes. Silencing of Hmgcs2 in young Leydig cells drives cell senescence and accelerated testicular aging. Mechanistically, β-hydroxybutyric acid upregulates the expression of Foxo3a by facilitating histone acetylation, thereby mitigating Leydig cells senescence and promoting testosterone production. Consistently, enhanced ketogenesis by genetic manipulation or oral β-hydroxybutyric acid supplementation alleviates Leydig cells senescence and ameliorates testicular aging in aged mice. These findings highlight defective ketogenesis as a pivotal factor in testicular aging, suggesting potential therapeutic avenues for addressing age-related testicular dysfunction.

Integration of single-cell and bulk transcriptomics reveals β-hydroxybutyrylation-related signatures in primary open-angle glaucoma

The pathophysiology of primary open-angle glaucoma (POAG), the most prevalent glaucoma type, is poorly understood. Although it is well known that epigenetic factors affect the progression of POAG, the impact of β-hydroxybutyrylation (Kbhb) on POAG remains unknown. Based on POAG-related datasets (GSE27276, GSE4316, and GSE231749) retrieved from the Gene Expression Omnibus (GEO) database, four biomarkers (FABP5, GLS, PDLIM1, and TAGLN) with a diagnostic value for POAG were identified by combining differential expression analysis, machine learning algorithms, and receiver operating characteristic (ROC) analysis. Immune infiltration analysis demonstrated significant differences in the infiltration abundances of 10 immune cells between POAG and controls, including regulatory T cells, monocytes, and macrophages, with notable positive correlations between TAGLN expression and these immune cells. Subsequently, single-cell analysis revealed that GLS, PDLIM1, and TAGLN were higher expressed in chondrocytes, smooth muscle cells, and endothelial cells. In addition, in vitro cellular experiments and animal models revealed that the TAGLN expression trend was consistent with the data from GSE27276 and GSE4316. In conclusion, TAGLN may play an important role in understanding of the molecular mechanisms of POAG and exploration of therapeutic targets.

Innovative therapeutics for renoprotection: Where we are

Chronic kidney disease (CKD) has become highly prevalent worldwide, with major implications for public health, including increased risk of progression to kidney failure, cardiovascular events, and mortality. Up to a decade ago, renin-angiotensin system inhibitors, that is angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers, were the only available pharmacological interventions to slow kidney function loss and limit the associated cardiovascular morbidity and mortality in this context. More recently, landmark trials have demonstrated the ability of novel therapeutics to significantly ameliorate kidney and cardiovascular outcomes in patients with CKD, when added on top of optimized renin-angiotensin system blockade. These include sodium-glucose cotransporter-2 inhibitors in patients with diabetic and nondiabetic kidney disease, as well as the nonsteroidal mineralcorticoid receptor antagonist finerenone and the glucagon-like peptide-1 receptor agonist semaglutide in patients with diabetic kidney disease. We herein review the evolving scenario and the latest evidence for the treatment of CKD, mainly focusing on proteinuric CKD. We started with a presentation of established and more recently approved classes of kidney protective drugs, followed by a discussion of therapeutic interventions under clinical investigation to slow CKD progression. Finally, we underscore the added value of personalized and multidrug interventions, which are becoming increasingly more feasible with the availability of a growing number of kidney protective agents, and are likely to stand as the most powerful tools to safely slow, or even prevent, the progression of proteinuric CKD. SIGNIFICANCE STATEMENT: Chronic kidney disease (CKD) is highly prevalent globally, and is associated with substantial morbidity and mortality. This review provides a comprehensive overview of the currently approved and emerging therapeutic options for the treatment of proteinuric CKD. As novel kidney protective agents have recently become available, the outcomes of patients with CKD could hopefully improve over the few decades ahead.

β-hydroxybutyrate attenuates diabetic renal and muscular pathologies in a streptozotocin-induced diabetic model

Diabetes and its associated complications are the leading cause of mortality worldwide. Strategies have been rapidly developed to reduce diabetic complications and the overall quality of life of patients with diabetes. β-hydroxybutyrate (BHB), the most abundant ketone body generated from fatty acids in the liver, provides energy sources under nutrient deprivation and has various potential health benefits as a functional food. However, its role in diabetic pathologies is unclear. In this study, we examined the effect of BHB on the kidney and muscle functions in streptozotocin (STZ)-induced diabetic mice. BHB supplementation exerted anti-inflammatory effects on the kidneys and improved renal tubule injury and fibrosis in STZ-induced mice. Furthermore, BHB alleviated diabetes-induced muscle atrophy, indicated by the increased fiber area and normalized fiber area distribution in BHB-supplemented STZ-treated mice. Our study demonstrates the beneficial effects of BHB in improving diabetic complications, particularly diabetic nephropathy and myopathy, and highlights the potential of BHB as a functional food for the treatment of diabetes.

Bisphenol S accelerates the progression of high fat diet-induced NAFLD by triggering ferroptosis via regulating HMGCS2

Bisphenol S (BPS) is a widely detected environmental toxin with the potential to increase the risk of non-alcoholic fatty liver disease (NAFLD). However, the effects of BPS on the progression of high fat diet (HFD)-induced NAFLD remain unclear. This study aimed to explore the role and underlying mechanisms of action of BPS in HFD-induced NAFLD. Our results showed that BPS exposure (50 and 500 μg/kg bodyweight/day) promoted the progression of NAFLD, which was evidenced by increased liver/body weight ratio, elevated serum alanine aminotransferase and aspartate aminotransferase levels, and more and larger lipid droplets in liver tissues. These phenomena were accompanied by abnormal expression levels of fatty acid uptake (Cd36), fatty acid synthesis (Pparγ, Scd-1, and Fasn), fatty acid oxidation (Pparα), and cytokines (TNFα, IL-1β, and IL-6). In vitro and in vivo studies showed that BPS exposure caused hepatic ferroptosis by regulating ferroptosis-related markers (GPX4, xCT, FTH, and ACSL4). Moreover, BPS exposure caused ROS overproduction, mitochondrial dysfunction, lipid peroxidation, and GSH suppression, all of which were restored by ferrostatin-1, a ferroptosis inhibitor. Moreover, BPS significantly upregulated HMGCS2 expression in the hepatocytes and liver tissues. 3-hydroxy-3-methylglutaryl coenzyme A synthetase 2 (HMGCS2) knockdown mitigated the effects of BPS on hepatocytes and reversed the expression of ferroptosis-related markers. Thus, BPS exposure aggravates HFD-induced NAFLD by regulating HMGCS2-mediated ferroptosis. Collectively, our study indicates that BPS exposure at environmentally relevant concentrations may aggravate NAFLD phenotypes under HFD conditions, highlighting the health risks of BPS to the liver.

Glucagon like peptide-1 modulates urinary sodium excretion in diabetic kidney disease via ENaC activation

Diabetic kidney disease (DKD) is a leading cause of end stage kidney disease. Elevated salt sensitivity by epithelial sodium channel (ENaC) overexpression may be a residual risk factor for DKD. We found that combination therapy of linagliptin (LINA) to empagliflozin (EMPA), but not EMPA alone decreased phosphorylated Nedd4-2 (p-Nedd4-2) and ENaC levels in DKD rats in association with the increased urinary sodium excretion (USE). More extensive renoprotective effects were observed by the combination therapy of LINA and EMPA in deoxycorticosterone and high salt-treated mice. Acute injection experiments showed time-lagged administration of LINA to EMPA increased USE, and its effect sustained until 3 h. High salt and high glucose increased p-Nedd4-2 and ENaC levels in cultured distal tubules, which was inhibited by LINA or glucagon like peptide-1 (GLP-1), but there were no additive effects of LINA on GLP-1, the latter of which was blocked by GLP-1 receptor agonist. USE was higher and ENaC expression was lower in DKD patients received SGLT2is and DPP4is than those without. Our present findings suggest that addition of LINA to EMPA decreases p-Nedd4-2 and ENaC levels via the activation of GLP-1-receptor axis, which could ameliorate salt sensitivity and help prevent kidney injury in DKD.

Maladaptive Peripheral Ketogenesis in Schwann Cells Mediated by CB1R Contributes to Diabetic Neuropathy

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes. Although studies have previously investigated metabolic disruptions in the peripheral nervous system (PNS), the exact metabolic mechanisms underlying DPN remain largely unknown. Herein, a specific form of metabolic remodeling involving aberrant ketogenesis within Schwann cells (SCs) in streptozotocin (STZ)-induced type I diabetes mellitus is identified. The PNS adapts poorly to such aberrant ketogenesis, resulting in disrupted energy metabolism, mitochondrial damage, and homeostatic decompensation, ultimately contributing to DPN. Additionally, the maladaptive peripheral ketogenesis is highly dependent on the cannabinoid type-1 receptor (CB1R)-Hmgcs2 axis. Silencing CB1R reprogrammed the metabolism of SCs by blocking maladaptive ketogenesis, resulting in rebalanced energy metabolism, reduced histopathological changes, and improved neuropathic symptoms. Moreover, this metabolic reprogramming can be induced pharmacologically using JD5037, a peripheral CB1R blocker. These findings revealed a new metabolic mechanism underlying DPN, and promoted CB1R as a promising therapeutic target for DPN.

Canagliflozin-induced renal glutathione distribution mapping in non-diabetic male rat kidneys

Canagliflozin, a sodium glucose cotransporter 2 (SGLT2) inhibitor, has direct renoprotective effects beyond lowering blood glucose levels. The inhibition of sodium reabsorption via SGLT2 reduces the overload on proximal tubules, thereby suppressing the generation of reactive oxygen species (ROS) and preventing a decline in renal function. To clarify the pharmacological mechanism of SGLT2 inhibitor, we investigated the effects of canagliflozin on oxidative stress in the kidneys of normal, non-diabetic Sprague-Dawley rats. Screening using mass spectrometry images revealed a significant elevation map of the reduced form of glutathione in the renal cortex of canagliflozin-treated non-diabetic rats. These results suggest that canagliflozin reduces oxidative stress through ROS scavenging mechanisms. Considering that ROS play major roles in renal dysfunction regardless of diabetes mellitus, these findings suggest that canagliflozin is applicable to a broader range of renal diseases beyond diabetes.

Dietary therapy to halt the progression of diabetes to diabetic kidney disease

Diabetic Kidney Disease (DKD) is a common and serious complication of diabetes, particularly Type 2 Diabetes Mellitus (T2DM), which significantly contributes to patient morbidity and mortality. The limitations of traditional treatments like ACE inhibitors and ARBs in managing DKD progression highlight the need for innovative therapeutic strategies. This review examines the impact of various dietary patterns, such as the Mediterranean diet, ketogenic diet, intermittent fasting, DASH diet, and vegetarian diet, on the management of DKD. Evidence suggests these diets can halt the progression of DKD, although further research is needed to confirm their long-term effectiveness and safety. Personalized dietary approaches tailored to individual needs may enhance outcomes for DKD patients.

Ketogenic diets and β-hydroxybutyrate in the prevention and treatment of diabetic kidney disease: current progress and future perspectives

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease. Ketogenic diets (KD) is a high-fat, low-carbohydrate diet. KD produces ketone bodies to supplement energy in the case of insufficient glucose in the body. β-Hydroxybutyrate (BHB) is the main component of ketone bodies. BHB serves as "ancillary fuel" substituting (but also inducing) anti-oxidative, anti-inflammatory, and cardio-protective features by binding to several target proteins, including histone acylation modification, or G protein-coupled receptors (GPCRs). KD have been used to treat epilepsy, obesity, type-2 diabetes mellitus, polycystic ovary syndrome, cancers, and other diseases. According to recent research, KD and the induced BHB delay DKD progression by improving the metabolism of glucose and lipids, regulating autophagy, as well as alleviating inflammation, oxidative stress and fibrosis. However, due to some side-effects, the role and mechanism of action of KD and BHB in the prevention and treatment of DKD are controversial. This review focuses on recent progress in the research of KD and BHB in clinical and preclinical studies of DKD, and provides new perspectives for DKD treatment.

Insights into the Roles of GLP-1, DPP-4, and SGLT2 at the Crossroads of Cardiovascular, Renal, and Metabolic Pathophysiology

In recent years, new drugs for the treatment of type 2 diabetes (T2D) have been proposed, including glucagon-like peptide 1 (GLP-1) agonists or sodium-glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors. Over time, some of these agents (in particular, GLP-1 agonists and SGLT2 inhibitors), which were initially developed for their glucose-lowering actions, have demonstrated significant beneficial pleiotropic effects, thus expanding their potential therapeutic applications. This review aims to discuss the mechanisms, pleiotropic effects, and therapeutic potential of GLP-1, DPP-4, and SGLT2, with a particular focus on their cardiorenal benefits beyond glycemic control.

Inflammation in glomerular diseases

The structural and functional integrity of glomerular cells is critical for maintaining normal kidney function. Glomerular diseases, which involve chronic histological damage to the kidney, are related to injury to glomerular cells such as endothelial cells, mesangial cells (MCs), and podocytes. When faced with pathogenic conditions, these cells release pro-inflammatory cytokines such as chemokines, inflammatory factors, and adhesion factors. These substances interact with glomerular cells through specific inflammatory pathways, resulting in damage to the structure and function of the glomeruli, ultimately causing glomerular disease. Although the role of inflammation in chronic kidney diseases is well known, the specific molecular pathways that result in glomerular diseases remain largely unclear. For a long time, it has been believed that only immune cells can secrete inflammatory factors. Therefore, targeted therapies against immune cells were considered the first choice for treating inflammation in glomerular disease. However, emerging research indicates that non-immune cells such as glomerular endothelial cells, MCs, and podocytes can also play a role in renal inflammation by releasing inflammatory factors. Similarly, targeted therapies against glomerular cells should be considered. This review aims to uncover glomerular diseases related to inflammation and pathways in glomerular inflammation, and for the first time summarized that non-immune cells in the glomerulus can participate in glomerular inflammatory damage by secreting inflammatory factors, providing valuable references for future strategies to prevent and treat glomerular diseases. More importantly, we emphasized targeted glomerular cell therapy, which may be a key direction for the future treatment of glomerular diseases.

Sodium-glucose co-transporter 2 (SGLT-2) inhibitors ameliorate renal ischemia-reperfusion injury (IRI) by modulating autophagic processes

Renal ischemia-reperfusion injury (IRI) is a common clinical condition that currently lacks effective treatment options. Inhibitors targeting the sodium-glucose co-transporter-2 (SGLT-2), recognized for their role in managing hyperglycemia, have demonstrated efficacy in enhancing the health outcomes for diabetic patients grappling with chronic kidney disease. Nevertheless, the precise impact of SGLT-2 inhibitors on renal ischemia-reperfusion injury (IRI) and the corresponding transcriptomic alterations remain to be elucidated. In our research, we developed a model of IRI using male C57BL/6 mice by clamping the unilateral renal artery and administering empagliflozin Transcriptomic alterations were analyzed using RNA sequencing (RNA-Seq), complemented by proteomic analysis to investigate the effects of empagliflozin. Histological assessments revealed increased renal inflammatory cell infiltration, widespread renal tubular injury, and elevated autophagosomes formation in the IRI group compared to controls. These pathological changes were significantly attenuated following empagliflozin treatment. Besides, renal function impairment can be alleviated in empagliflozin-treated group. RNA-Seq analysis identified lysosomal autophagy as a key biological process in IRI mice. Empagliflozin exerted a renoprotective effect by downregulating lysosome-associated membrane proteins, primarily LAMP1, LAMP2, and LAMP4 (CD68), through the PI3K-Akt, MAPK, and mTOR signaling pathways, thereby inhibiting autophagic processes. In conclusion, this study highlights enhanced inflammation and disrupted metabolism as hallmark transcriptomic signatures of renal. Furthermore, it demonstrates the renoprotective effects of empagliflozin in alleviating renal IRI by modulating autophagic processes.

Mitochondrial Dysfunction in Diabetes: Shedding Light on a Widespread Oversight

Diabetes mellitus represents a complicated metabolic condition marked by ongoing hyperglycemia arising from impaired insulin secretion, inadequate insulin action, or a combination of both. Mitochondrial dysfunction has emerged as a significant contributor to the aetiology of diabetes, affecting various metabolic processes critical for glucose homeostasis. This review aims to elucidate the complex link between mitochondrial dysfunction and diabetes, covering the spectrum of diabetes types, the role of mitochondria in insulin resistance, highlighting pathophysiological mechanisms, mitochondrial DNA damage, and altered mitochondrial biogenesis and dynamics. Additionally, it discusses the clinical implications and complications of mitochondrial dysfunction in diabetes and its complications, diagnostic approaches for assessing mitochondrial function in diabetics, therapeutic strategies, future directions, and research opportunities.

Targeting senescence to prevent diabetic kidney disease: Exploring molecular mechanisms and potential therapeutic targets for disease management

BACKGROUND/AIMS

As a microvascular complication, diabetic kidney disease is the leading cause of chronic kidney disease and end-stage renal disease worldwide. While the underlying pathophysiology driving transition of diabetic kidney disease to renal failure is yet to be fully understood, recent studies suggest that cellular senescence is central in disease development and progression. Consequently, understanding the molecular mechanisms which initiate and drive senescence in response to the diabetic milieu is crucial in developing targeted therapies that halt progression of renal disease.

METHODS

To understand the mechanistic pathways underpinning cellular senescence in the context of diabetic kidney disease, we reviewed the literature using PubMed for English language articles that contained key words related to senescence, inflammation, fibrosis, senescence-associated secretory phenotype (SASP), autophagy, and diabetes.

RESULTS

Aberrant accumulation of metabolically active senescent cells is a notable event in the progression of diabetic kidney disease. Through autocrine- and paracrine-mediated mechanisms, resident senescent cells potentiate inflammation and fibrosis through increased expression and secretion of pro-inflammatory cytokines, chemoattractants, recruitment of immune cells, myofibroblast activation, and extracellular matrix remodelling. Compounds that eliminate senescent cells and/or target the SASP - including senolytic and senomorphics drugs - demonstrate promising results in reducing the senescent cell burden and associated pro-inflammatory effect.

CONCLUSIONS

Here we evidence the link between senescence and diabetic kidney disease and highlight underlying molecular mechanisms and potential therapeutic targets that could be exploited to delay disease progression and improve outcomes for individuals with the disease. Trials are now required to translate their therapeutic potential to a clinical setting.

Pemafibrate ameliorates renal injury through induction of FGF21 and ketone body production in male mice

Chronic kidney disease is a life-threatening disease worldwide. PPARα is a crucial transcriptional regulator of lipid metabolism and inflammation. Here, we examine whether a novel selective PPARα modulator, pemafibrate modulates renal injury in a model of unilateral ureteral obstruction (UUO). Administration of pemafibrate to wild-type (WT) mice led to reduction of renal dysfunction and fibrosis after UUO with accompanying increases in plasma levels of fibroblast growth factor (FGF) 21 and ketone body β-hydroxybutyrate (BHB). Treatment of WT mice with FGF21 or BHB precursor resulted in attenuation of renal fibrotic and inflammatory responses after UUO. Treatment of proximal tubular cells with FGF21 or BHB reduced expression of epithelial-mesenchymal transition markers. These findings suggest that pemafibrate could ameliorate renal damage, at least in part, by its abilities to increase the production of FGF21 and BHB.

Exploring the Role of SGLT2 Inhibitors in Cancer: Mechanisms of Action and Therapeutic Opportunities

Cancer cells utilize larger amounts of glucose than their normal counterparts, and the expression of GLUT transporters is a known diagnostic target and a prognostic factor for many cancers. Recent evidence has shown that sodium-glucose transporters are also expressed in different types of cancer, and SGLT2 has raised particular interest because of the current availability of anti-diabetic drugs that block SGLT2 in the kidney, which could be readily re-purposed for the treatment of cancer. The aim of this article is to perform a narrative review of the existing literature and a critical appraisal of the evidence for a role of SGLT2 inhibitors for the treatment and prevention of cancer. SGLT2 inhibitors block Na-dependent glucose uptake in the proximal kidney tubules, leading to glycosuria and the improvement of blood glucose levels and insulin sensitivity in diabetic patients. They also have a series of systemic effects, including reduced blood pressure, weight loss, and reduced inflammation, which also make them effective for heart failure and kidney disease. Epidemiological evidence in diabetic patients suggests that individuals treated with SGLT2 inhibitors may have a lower incidence and better outcomes of cancer. These studies are confirmed by pre-clinical evidence of an effect of SGLT2 inhibitors against cancer in xenograft and genetically engineered models, as well as by in vitro mechanistic studies. The action of SGLT2 inhibitors in cancer can be mediated by the direct inhibition of glucose uptake in cancer cells, as well as by systemic effects. In conclusion, there is evidence suggesting a potential role of SGLT2 inhibitors against different types of cancer. The most convincing evidence exists for lung and breast adenocarcinomas, hepatocellular carcinoma, and pancreatic cancer. Several ongoing clinical trials will provide more information on the efficacy of SGLT2 inhibitors against cancer.

Transcriptomics of SGLT2-positive early proximal tubule segments in mice: response to type 1 diabetes, SGLT1/2 inhibition, or GLP1 receptor agonism

SGLT2 inhibitors (SGLT2i) and GLP1 receptor (GLP1R) agonists have kidney protective effects. To better understand their molecular effects, RNA sequencing was performed in SGLT2-positive proximal tubule segments isolated by immunostaining-guided laser capture microdissection. Male adult DBA wild-type (WT) and littermate diabetic Akita mice ± Sglt1 knockout (Sglt1-KO) were given vehicle or SGLT2i dapagliflozin (dapa; 10 mg/kg diet) for 2 wk, and other Akita mice received GLP1R agonist semaglutide [sema; 3 nmol/(kg body wt·day), sc]. Dapa (254 ± 11 mg/dL) and Sglt1-KO (367 ± 11 mg/dL) but not sema (407 ± 44 mg/dL) significantly reduced hyperglycemia in Akita mice (480 ± 33 mg/dL). The 20,748 detected annotated protein-coding genes included robust enrichment of S1-segment marker genes. Akita showed 198 (∼1%) differentially expressed genes versus WT (DEGs; adjusted P ≤ 0.1), including downregulation of anionic transport, unsaturated fatty acid, and carboxylic acid metabolism. Dapa changed only two genes in WT but restored 43% of DEGs in Akita, including upregulation of the lipid metabolic pathway, carboxylic acid metabolism, and organic anion transport. In Akita, sema restored ∼10% of DEGs, and Sglt1-KO and dapa were synergistic (restored ∼61%), possibly involving additive blood glucose effects (193 ± 15 mg/dL). Targeted analysis of transporters and channels (t test, P < 0.05) revealed that ∼10% of 526 detectable transporters and channels were downregulated by Akita, with ∼60% restored by dapa. Dapa, dapa + Sglt1-KO, and sema also altered Akita-insensitive genes. Among DEGs in Akita, ∼30% were unresponsive to any treatment, indicating potential new targets. In conclusion, SGLT2i restored transcription for multiple metabolic pathways and transporters in SGLT2-positive proximal tubule segments in diabetic mice, with a smaller effect also observed for GLP1R agonism.NEW & NOTEWORTHY SGLT2 inhibitors and GLP1 receptor agonists have kidney protective effects. By combining immunostaining-guided laser capture microdissection and RNA sequencing, the study established how the gene expression profile changes in SGLT2-positive proximal tubule cells in response to type 1 Akita diabetes and to pharmacological intervention by SGLT2 inhibition or GLP1R agonism and genetic deletion of SGLT1. The data also indicate genes unresponsive to those treatments that may include new therapeutical candidates.

Lack of renoprotective effects by long-term PCSK9 and SGLT2 inhibition using alirocumab and empagliflozin in obese ZSF1 rats

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular disease (CVD). Despite the entry of sodium glucose cotransporter 2 (SGLT2) inhibitors, CKD persists as a medical challenge. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition reduces low-density lipoprotein (LDL)-cholesterol, a major risk factor of CVD. Interestingly, studies indicate that PCSK9 inhibition decreases proteinuria in kidney disease, complementing the reduced CVD risk. This study aimed to validate obese ZSF1 rats as a model for the renoprotective effects of PCSK9 and SGLT2 inhibition using alirocumab and empagliflozin for 15 wk. Obese rats revealed a significant reduction in measured glomerular filtration rate (mGFR) and increased urine albumin/creatinine ratio (UACR) during follow-up compared with lean controls. Alirocumab treatment resulted in a decline in mGFR and increased UACR compared with vehicle-treated obese rats. Immunohistochemistry showed increased fibrosis and inflammation in kidney tissue from obese rats treated with empagliflozin or alirocumab, whereas hepatic cholesterol and triglyceride levels were lowered compared with vehicle-treated obese rats. Although alirocumab lowered circulating free cholesterol levels throughout the treatment period, certain cholesteryl esters were increased at the end of the study, resulting in no overall difference in total cholesterol levels in the alirocumab group. Correspondingly, only a trend toward increased hepatic LDL-receptor levels was observed. In conclusion, these findings suggest that alirocumab treatment aggravates kidney dysfunction in obese ZSF1 rats. Moreover, in contrast to the renoprotective properties of empagliflozin observed in patients with CKD, empagliflozin did not ameliorate kidney disease progression in the obese ZSF1 rat.NEW & NOTEWORTHY New treatments to slow kidney disease progression and reduce cardiovascular disease risk are needed for chronic kidney disease (CKD). We investigated the cholesterol-lowering PCSK9 inhibitor alirocumab as a new treatment for proteinuric CKD and the effect of SGLT2 inhibition using empagliflozin in obese ZSF1 rats. Regarding renoprotection, our findings were contradictory with previous preclinical studies and clinical data, suggesting that different pathophysiological mechanisms may apply to this rat model.

Identification and Validation of T Cell-Related Hub Biomarkers for Early Diagnosis of Diabetic Kidney Disease Using Single-Cell and Bulk Dataset Analysis

Diabetic kidney disease (DKD) is the most common complication of diabetes and a leading cause of chronic kidney disease that frequently leads to end-stage renal disease (ESRD). The pathogenesis of DKD is complex and is not fully understood. This study was designed to identify key targets for DKD diagnosis and explore the underlying molecular mechanisms.

METHODS

DKD-specific clusters were selected from single-cell datasets. Gene modules were identified using hairpin-dynamic weighted gene co-expression network analysis (hdWGCNA). Multiple machine learning algorithms were applied to model and screen hub genes from two bulk datasets. Rat model of DKD was built using optical microscopes to observe the histopathological changes in the kidney by HE, PAS, and Masson staining. The expression of RASGRP3, PDE3B, and CD247 in DKD-Rat was verified by RT-PCR, and the expression of RASGRP3, PDE3B, and CD247 in the serum samples of DKD patients was verified by ELISA. The results of sex and age, RASGRP3, PDE3B, CD247 were calculated by multivariate logistic regression analysis.

RESULTS

Three hub genes were obtained through screening single-cell and two bulk datasets. In-depth exploration of the potential molecular mechanisms of the hub genes was conducted using gene set variation analysis (GSVA), immune infiltration analysis, and single-cell correlation analysis. Receiver operating characteristic (ROC) curve confirmed a high diagnostic value of the hub biomarkers, and a high-efficiency diagnostic model was constructed and mutually validated in the two datasets. We found that damaged tubular number and interstitial fibrotic percentage were significantly increased in DKD rat. As shown by HE, PAS and Masson staining, the mRNA levels of PDE3B and CD247 were markedly upregulated in DKD rat compared with those in the control group. Lower expression levels of RASGRP3 mRNA were manifested in DKD. The levels of RASGRP3, PDE3B, CD247 in DKD patients by ELISA were statistically significant (p < 0.05). PDE3B and CD247 had an AUC value greater than 0.9,RASGRP3 had an AUC value greater than 0.7.

CONCLUSION

This study identified 3 T cell-related hub biomarkers, providing references for the early diagnosis of DKD and changes in T cells during DKD progression.

Unveiling the podocyte-protective effect of sodium-glucose cotransporter-2 inhibitors

The renoprotective effects of sodium-glucose cotransporter-2 (SGLT2) inhibitors in both diabetic and nondiabetic nephropathy are widely recognized due to results from randomized controlled trials notably the DAPA-CKD and EMPA-KIDNEY trials. Research exploring the mechanisms of renoprotection indicates that SGLT2 inhibitors exert protective effects on podocytes by enhancing autophagy and stabilizing the structure of podocytes and basement membranes. Furthermore, reductions in lipotoxicity, oxidative stress, and inflammation have been confirmed with SGLT2 inhibitor treatment. Recent clinical studies have also begun to explore the effects of SGLT2 inhibitors on nondiabetic podocytopathies, such as focal segmental glomerulosclerosis. In this review, we summarize clinical and laboratory studies that focus on the podocyte-protective effects of SGLT2 inhibitors, exploring the potential for broader applications of this novel therapeutic agent in kidney disease.

Sodium glucose transporter 2 inhibitors: Will these drugs benefit non-diabetic veterinary patients with cardiac and kidney diseases?

Sodium glucose transporter type 2 (SGLT2) inhibitors have been introduced into human medicine where their beneficial effects go beyond the expected improvement in blood glucose control. These drugs appear to prevent progression of both cardiovascular and kidney diseases, not only in diabetic but also in non-diabetic human patients. As these drugs have received conditional approval for use in diabetic cats and are being used in other veterinary species, the intriguing question as to whether they will have similar cardioprotective and nephroprotective effects in dogs and cats is being asked. The primary mechanism(s) by which SGLT2 inhibitors are cardio- and nephroprotective remain to be fully characterized. This paper reviews these suggested mechanisms in the context of the pathophysiology of progressive cardiovascular and kidney diseases in dogs and cats with the goal of predicting which categories of non-diabetic veterinary patients these drugs might be of most benefit.

Fasting substrates predict chronic kidney disease progression in CREDENCE trial patients with type 2 diabetes

BACKGROUNDSodium-glucose cotransporter 2 inhibitors slow down progression of chronic kidney disease (CKD). We tested whether the circulating substrate mix is related to CKD progression and cardiovascular outcomes in patients with type 2 diabetes (T2D) and albuminuric CKD in the CREDENCE trial.METHODSWe measured fasting substrates in 2,543 plasma samples at baseline and 1 year after randomization to either 100 mg canagliflozin or placebo and used multivariate Cox models to explore their association with CKD progression, heart failure hospitalization/cardiovascular death (hHF/CVD), and mortality.RESULTSHigher baseline lactate and free fatty acids (FFAs) were independently associated with a lower risk of CKD progression (HR = 0.73 [95% CI: 0.54-0.98] and HR = 0.67 [95% CI: 0.48-0.95], respectively) and hHF/CVD HR = 0.70 [95% CI: 0.50-0.99] and HR = 0.63 [95% CI: 0.42-0.94]). Canagliflozin led to a rise in plasma FFAs, glycerol, β-hydroxybutyrate, and acetoacetate. Changes in substrate between baseline and year 1 predicted an approximately 30% reduction in relative risk of both CKD progression and hHF/CVD independently of treatment. More patients who did not respond to canagliflozin treatment in terms of CKD progression belonged to the bottom lactate and FFA distribution tertiles.CONCLUSIONIn T2D patients with albuminuric CKD, basic energy substrates selectively influenced major long-term endpoints; canagliflozin treatment amplified their effects by chronically raising their circulating levels.

Exogenous Ketones in Cardiovascular Disease and Diabetes: From Bench to Bedside

Ketone bodies are molecules produced from fatty acids in the liver that act as energy carriers to peripheral tissues when glucose levels are low. Carbohydrate- and calorie-restricted diets, known to increase the levels of circulating ketone bodies, have attracted significant attention in recent years due to their potential health benefits in several diseases. Specifically, increasing ketones through dietary modulation has been reported to be beneficial for cardiovascular health and to improve glucose homeostasis and insulin resistance. Interestingly, although excessive production of ketones may lead to life-threatening ketoacidosis in diabetic patients, mounting evidence suggests that modest levels of ketones play adaptive and beneficial roles in pancreatic beta cells, although the exact mechanisms are still unknown. Of note, Sodium-Glucose Transporter 2 (SGLT2) inhibitors have been shown to increase the levels of beta-hydroxybutyrate (BHB), the most abundant ketone circulating in the human body, which may play a pivotal role in mediating some of their protective effects in cardiovascular health and diabetes. This systematic review provides a comprehensive overview of the scientific literature and presents an analysis of the effects of ketone bodies on cardiovascular pathophysiology and pancreatic beta cell function. The evidence from both preclinical and clinical studies indicates that exogenous ketones may have significant beneficial effects on both cardiomyocytes and pancreatic beta cells, making them intriguing candidates for potential cardioprotective therapies and to preserve beta cell function in patients with diabetes.

Inhibition of the RXRA-PPARα-FABP4 signaling pathway alleviates vascular cellular aging by an SGLT2 inhibitor in an atherosclerotic mice model

Atherosclerosis is the pathological cause of atherosclerotic cardiovascular disease (ASCVD), which rapidly progresses during the cellular senescence. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) reduce major cardiovascular events in patients with ASCVD and have potential antisenescence effects. Here, we investigate the effects of the SGLT2 inhibitor dapagliflozin on cellular senescence in atherosclerotic mice. Compared with ApoE-/- control mice treated with normal saline, those in the ApoE-/- dapagliflozin group, receiving intragastric dapagliflozin (0.1 mg kg-1 d-1) for 14 weeks, exhibited the reduction in the total aortic plaque area (48.8%±6.6% vs. 74.6%±8.0%, P<0.05), the decrease in the lipid core area ((0.019±0.0037) mm2vs. (0.032±0.0062) mm2, P<0.05) and in the percentage of senescent cells within the plaques (16.4%±3.7% vs. 30.7%±2.0%, P<0.01), while the increase in the thickness of the fibrous cap ((21.6±2.1) µm vs. (14.6±1.5) µm, P<0.01). Transcriptome sequencing of the aortic arch in the mice revealed the involvement of the PPARα and the fatty acid metabolic signaling pathways in dapagliflozin's mechanism of ameliorating cellular aging and plaque progression. In vitro, dapagliflozin inhibited the expression of PPARα and its downstream signal FABP4, by which the accumulation of senescent cells in human aortic smooth muscle cells (HASMCs) was reduced under high-fat conditions. This effect was accompanied by a reduction in the intracellular lipid content and alleviation of oxidative stress. However, these beneficial effects of dapagliflozin could be reversed by the PPARα overexpression. Bioinformatics analysis and molecular docking simulations revealed that dapagliflozin might exert its effects by directly interacting with the RXRA protein, thereby influencing the expression of the PPARα signaling pathway. In conclusion, the cellular senescence of aortic smooth muscle cells is potentially altered by dapagliflozin through the suppression of the RXRA-PPARα-FABP4 signaling pathway, resulting in a deceleration of atherosclerotic progression.

RBBP6-Mediated ERRα Degradation Contributes to Mitochondrial Injury in Renal Tubular Cells in Diabetic Kidney Disease

Diabetic Kidney Disease (DKD), a major precursor to end-stage renal disease, involves mitochondrial dysfunction in proximal renal tubular cells (PTCs), contributing to its pathogenesis. Estrogen-related receptor α (ERRα) is essential for mitochondrial integrity in PTCs, yet its regulation in DKD is poorly understood. This study investigates ERRα expression and its regulatory mechanisms in DKD, assessing its therapeutic potential. Using genetic, biochemical, and cellular approaches, ERRα expression Was examined in human DKD specimens and DKD mouse models. We identified the E3 ubiquitin ligase retinoblastoma binding protein 6 (RBBP6) as a regulator of ERRα, promoting its degradation through K48-linked polyubiquitination at the K100 residue. This degradation pathway significantly contributed to mitochondrial injury in PTCs of DKD models. Notably, conditional ERRα overexpression or RBBP6 inhibition markedly reduced mitochondrial damage in diabetic mice, highlighting ERRα's protective role in maintaining mitochondrial integrity. The interaction between RBBP6 and ERRα opens new therapeutic avenues, suggesting that modulating RBBP6-ERRα interactions could be a strategy for preserving mitochondrial function and slowing DKD progression.

Nutritional assessment and medical dietary therapy for management of obesity in patients with non-dialysis chronic kidney disease: a practical guide for endocrinologist, nutritionists and nephrologists. A consensus statement from the Italian society of endocrinology (SIE), working group of the club nutrition-hormones and metabolism; the Italian society of nutraceuticals (SINut), club ketodiets and nutraceuticals "KetoNut-SINut"; and the Italian society of nephrology (SIN)

PURPOSE

Chronic kidney disease (CKD) is a serious health concern with an estimated prevalence of about 13.4% worldwide. It is cause and consequence of various comorbidities, including cardiovascular diseases. In parallel, common pathological conditions closely related to ageing and unhealthy dietary habits increase the risk of CKD development and progression, including type 2 diabetes and obesity. Among these, obesity is either independent risk factor for new onset kidney disease or accelerates the rate of decline of kidney function by multiple mechanisms. Therefore, the role of diets aimed at attaining weight loss in patients with obesity is clearly essential to prevent CKD as to slow disease progression. Various dietary approaches have been licensed for the medical dietary therapy in CKD, including low-protein diet and Mediterranean diet. Interestingly, emerging evidence also support the use of low-carbohydrate/ketogenic diet (LCD/KD) in these patients. More specifically, LCD/KDs may efficiently promote weight loss, improve metabolic parameters, and reduce inflammation and oxidative stress, resulting in a dietary strategy that act globally in managing collateral conditions that are directly and indirectly related to the kidney function.

CONCLUSION

This consensus statement from the Italian Society of Endocrinology (SIE), working group of the Club Nutrition - Hormones and Metabolism; the Italian Society of Nutraceuticals (SINut), Club Ketodiets and Nutraceuticals "KetoNut-SINut"; and the Italian Society of Nephrology (SIN) is intended to be a guide for Endocrinologist, Nutritionists and Nephrologist who deal with the management of patients with obesity with non-dialysis CKD providing a practical guidance on assessing nutritional status and prescribing the optimal diet in order to best manage obesity to prevent CKD and its progression to dialysis.

Handling the sugar rush: the role of the renal proximal tubule

Blood glucose homeostasis is critical to ensure the proper functioning of the human body. Through the processes of filtration, reabsorption, secretion, and metabolism, much of this task falls to the kidneys. With a rise in glucose and other added sugars, there is an increased burden on this organ, mainly the proximal tubule, which is responsible for all glucose reabsorption. In this review, we focus on the current physiological and cell biological functions of the renal proximal tubule as it works to reabsorb and metabolize glucose and fructose. We also highlight the physiological adaptations that occur within the proximal tubule as sugar levels rise under pathophysiological conditions including diabetes. This includes the detrimental impacts of an excess glucose load that leads to glucotoxicity. Finally, we explore some of the emerging therapeutics that modulate renal glucose handling and the systemic protection that can be realized by targeting the reabsorptive properties of the kidney.

Unraveling Diabetic Kidney Disease: The Roles of Mitochondrial Dysfunction and Immunometabolism

Mitochondria are essential for cellular energy production and are implicated in numerous diseases, including diabetic kidney disease (DKD). Current evidence indicates that mitochondrial dysfunction results in alterations in several metabolic pathways within kidney cells, thereby contributing to the progression of DKD. Furthermore, mitochondrial dysfunction can engender an inflammatory milieu, leading to the activation and recruitment of immune cells to the kidney tissue, potentially perturbing intrarenal metabolism. In addition, this inflammatory microenvironment has the potential to modify immune cell metabolism, which may further accentuate the immune-mediated kidney injury. This understanding has led to the emerging field of immunometabolism, which views DKD as not just a metabolic disorder caused by hyperglycemia but also one with significant immune contributions. Targeting mitochondrial function and immunometabolism may offer protective effects for the kidneys, complementing current therapies and potentially mitigating the risk of DKD progression. This comprehensive review examines the impact of mitochondrial dysfunction and the potential role of immunometabolism in DKD. We also discuss tools for investigating these mechanisms and propose avenues for integrating this research with existing therapies. These insights underscore the modulation of mitochondrial function and immunometabolism as a critical strategy for decelerating DKD progression.

Oxidative Stress in Kidney Injury and Hypertension

Hypertension (HTN) is a major contributor to kidney damage, leading to conditions such as nephrosclerosis and hypertensive nephropathy, significant causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD). HTN is also a risk factor for stroke and coronary heart disease. Oxidative stress, inflammation, and activation of the renin-angiotensin-aldosterone system (RAAS) play critical roles in causing kidney injury in HTN. Genetic and environmental factors influence the susceptibility to hypertensive renal damage, with African American populations having a higher tendency due to genetic variants. Managing blood pressure (BP) effectively with treatments targeting RAAS activation, oxidative stress, and inflammation is crucial in preventing renal damage and the progression of HTN-related CKD and ESRD. Interactions between genetic and environmental factors impacting kidney function abnormalities are central to HTN development. Animal studies indicate that genetic factors significantly influence BP regulation. Anti-natriuretic mechanisms can reset the pressure-natriuresis relationship, requiring a higher BP to excrete sodium matched to intake. Activation of intrarenal angiotensin II receptors contributes to sodium retention and high BP. In HTN, the gut microbiome can affect BP by influencing energy metabolism and inflammatory pathways. Animal models, such as the spontaneously hypertensive rat and the chronic angiotensin II infusion model, mirror human essential hypertension and highlight the significance of the kidney in HTN pathogenesis. Overproduction of reactive oxygen species (ROS) plays a crucial role in the development and progression of HTN, impacting renal function and BP regulation. Targeting specific NADPH oxidase (NOX) isoforms to inhibit ROS production and enhance antioxidant mechanisms may improve renal structure and function while lowering blood pressure. Therapies like SGLT2 inhibitors and mineralocorticoid receptor antagonists have shown promise in reducing oxidative stress, inflammation, and RAAS activity, offering renal and antihypertensive protection in managing HTN and CKD. This review emphasizes the critical role of NOX in the development and progression of HTN, focusing on its impact on renal function and BP regulation. Effective BP management and targeting oxidative stress, inflammation, and RAAS activation, is crucial in preventing renal damage and the progression of HTN-related CKD and ESRD.

Tofogliflozin attenuates renal lipid deposition and inflammation via PPARα upregulation mediated by miR-21a impairment in diet-induced steatohepatitic mice

We previously demonstrated hepatic, cardiac, and skin inflammation in a high-fat diet-induced steatotic liver disease (SLD) model. However, the molecular mechanism in the kidneys in this model remains unclear. It has been recently reported that SGLT2 inhibitors improve chronic kidney disease (CKD). Therefore, we used this model to evaluate the effects of tofogliflozin on renal lipid metabolism and inflammation. Male 8-10-week-old C57Bl/6 mice were fed a high-fat/high-cholesterol/high-sucrose/bile acid (HF/HC/HS/BA) diet with 0.015% tofogliflozin (Tofo group) or an HF/HC/HS/BA diet alone (SLD group). After eight weeks, serum lipid profiles, histology, lipid content, and mRNA/microRNA and protein expression levels in the kidney were examined. The Tofo group showed significant reductions in body (26.9 ± 0.9 vs. 24.5 ± 1.0 g; p < 0.001) and kidney weight compared to those of the SLD group. Renal cholesterol (9.1 ± 1.6 vs. 7.5 ± 0.7 mg/g; p < 0.05) and non-esterified fatty acid (NEFA) (12.0 ± 3.0 vs. 8.4 ± 1.5 μEq/g; p < 0.01) were significantly decreased in the Tofo group. Transmission electron microscopy revealed the presence of fewer lipid droplets. mRNA sequencing analysis revealed that fatty acid metabolism-related genes were upregulated and NFκB signaling pathway-related genes were downregulated in the Tofo group. MicroRNA sequencing analysis indicated that miR-21a was downregulated and miR-204 was upregulated in the Tofo group. Notably, the expression of PPARα, which has been known to be negatively regulated by miR-21, was significantly increased, leading to enhancing β-oxidation genes, Acox1 and Cpt1 in the Tofo group. Tofogliflozin decreased renal cholesterol and NEFA levels and improved inflammation through the regulation of PPARα and miR-21a.

Striking senescence with sodium transporter inhibition

Senescence is associated with multiple morbidities and therapeutic targeting of these cells is a key aim. In a recent study, Katsuumi et al. found that targeting sodium-glucose co-transporter 2 (SGLT2) promoted immune clearance of senescent cells via programmed cell death-1 ligand (PD-L1) suppression, thus promoting immunosurveillance. This could have profound implications for many age-related diseases, including cancer and frailty.

Partial reduction of interleukin-33 signaling improves senescence and renal injury in diabetic nephropathy

Diabetic nephropathy (DN) is a frequent and costly complication of diabetes with limited understandings of mechanisms and therapies. Emerging evidence points to the important roles of interleukin-33 (IL-33) in acute kidney injury, yet its contribution to DN is still unclear. We here found a ubiquitous increase of IL-33 and its receptor (ST2) in murine models and patients with DN. Surprisingly, both IL-33 and ST2 knockdown aggravated renal lesions in DN, while overexpression of IL-33 also exacerbated the condition. Further population-based analyses revealed a positive correlation of IL-33 expression with renal dysfunction in DN patients. Individuals with high IL-33 expression-related polygenic risk score had a higher DN risk. These findings confirmed the harmful effects of IL-33 on DN. Conversely, endogenous and exogenous partial reduction of IL-33 signaling conferred renoprotective effects in vivo and in vitro. Mechanistically, IL-33 induced senescence by regulating cell cycle factors in HK-2 cells, and accordingly senescence led to renal cell damage through the secretion of senescence-related secretory phenotype (SASP) including IL-33 and prostaglandins. Together, elevated IL-33 accelerates cellular senescence to drive DN possibly by SASP production, while a partial blockage improves renal injury and senescence. Our findings pinpoint a possible and new avenue for DN interventions.

Podocyte-targeted therapies - progress and future directions

Podocytes are the key target cells for injury across the spectrum of primary and secondary proteinuric kidney disorders, which account for up to 90% of cases of kidney failure worldwide. Seminal experimental and clinical studies have established a causative link between podocyte depletion and the magnitude of proteinuria in progressive glomerular disease. However, no substantial advances have been made in glomerular disease therapies, and the standard of care for podocytopathies relies on repurposed immunosuppressive drugs. The past two decades have seen a remarkable expansion in understanding of the mechanistic basis of podocyte injury, with prospects increasing for precision-based treatment approaches. Dozens of disease-causing genes with roles in the pathogenesis of clinical podocytopathies have been identified, as well as a number of putative glomerular permeability factors. These achievements, together with the identification of novel targets of podocyte injury, the development of potential approaches to harness the endogenous podocyte regenerative potential of progenitor cell populations, ongoing clinical trials of podocyte-specific pharmacological agents and the development of podocyte-directed drug delivery systems, contribute to an optimistic outlook for the future of glomerular disease therapy.

SGLT2 inhibitor promotes ketogenesis to improve MASH by suppressing CD8+ T cell activation

During the progression of metabolic dysfunction-associated steatohepatitis (MASH), the accumulation of auto-aggressive CD8+ T cells significantly contributes to liver injury and inflammation. Empagliflozin (EMPA), a highly selective inhibitor of sodium-glucose co-transporter 2 (SGLT2), exhibits potential therapeutic benefits for liver steatosis; however, the underlying mechanism remains incompletely elucidated. Here, we found that EMPA significantly reduced the hepatic accumulation of auto-aggressive CD8+ T cells and lowered granzyme B levels in mice with MASH. Mechanistically, EMPA increased β-hydroxybutyric acid by promoting the ketogenesis of CD8+ T cells via elevating 3-hydroxybutyrate dehydrogenase 1 (Bdh1) expression. The β-hydroxybutyric acid subsequently inhibited interferon regulatory factor 4 (Irf4), which is crucial for CD8+ T cell activation. Furthermore, the ablation of Bdh1 in T cells aggravated the manifestation of MASH and hindered the therapeutic efficacy of EMPA. Moreover, a case-control study also showed that SGLT2 inhibitor treatment repressed CD8+ T cell infiltration and improved liver injury in patients with MASH. In summary, our study indicates that SGLT2 inhibitors can target CD8+ T cells and may be an effective strategy for treating MASH.

Renoprotective effects of empagliflozin in high-fat diet-induced obesity-related glomerulopathy by regulation of gut-kidney axis

The increasing prevalence of obesity-related glomerulopathy (ORG) poses a significant threat to public health. Sodium-glucose cotransporter-2 (SGLT2) inhibitors effectively reduce body weight and total fat mass in individuals with obesity and halt the progression of ORG. However, the underlying mechanisms of their reno-protective effects in ORG remain unclear. We established a high-fat diet-induced ORG model using C57BL/6J mice, which were divided into three groups: normal chow diet (NCD group), high-fat diet (HFD) mice treated with placebo (ORG group), and HFD mice treated with empagliflozin (EMPA group). We conducted 16S ribosomal RNA gene sequencing of feces and analyzed metabolites from kidney, feces, liver, and serum samples. ORG mice showed increased urinary albumin creatinine ratio, cholesterol, triglyceride levels, and glomerular diameter compared with NCD mice (all P < 0.05). EMPA treatment significantly alleviated these parameters (all P < 0.05). Multitissue metabolomics analysis revealed lipid metabolic reprogramming in ORG mice, which was significantly altered by EMPA treatment. MetOrigin analysis showed a close association between EMPA-related lipid metabolic pathways and gut microbiota alterations, characterized by reduced abundances of Firmicutes and Desulfovibrio and increased abundance of Akkermansia (all P < 0.05). The metabolic homeostasis of ORG mice, especially in lipid metabolism, was disrupted and closely associated with gut microbiota alterations, contributing to the progression of ORG. EMPA treatment improved kidney function and morphology by regulating lipid metabolism through the gut-kidney axis, highlighting a novel therapeutic approach for ORG. NEW & NOTEWORTHY Our study uncovered that empagliflozin (EMPA) potentially protects renal function and morphology in obesity-related glomerulopathy (ORG) mice by regulating the gut-kidney axis. EMPA's reno-protective effects in ORG mice are associated with the lipid metabolism, especially in glycerophospholipid metabolism and the pantothenate/CoA synthesis pathways. EMPA's modulation of gut microbiota appears to be pivotal in suppressing glycerol 3-phosphate and CoA synthesis. The insights into gut microbiota-host metabolic interactions offer a novel therapeutic approach for ORG.

Trigger Warning: How Modern Diet, Lifestyle, and Environment Pull the Trigger on Autosomal Dominant Polycystic Kidney Disease Progression

Understanding chronic kidney disease (CKD) through the lens of evolutionary biology highlights the mismatch between our Paleolithic-optimized genes and modern diets, which led to the dramatically increased prevalence of CKD in modern societies. In particular, the Standard American Diet (SAD), high in carbohydrates and ultra-processed foods, causes conditions like type 2 diabetes (T2D), chronic inflammation, and hypertension, leading to CKD. Autosomal dominant polycystic kidney disease (ADPKD), a genetic form of CKD, is characterized by progressive renal cystogenesis that leads to renal failure. This review challenges the fatalistic view of ADPKD as solely a genetic disease. We argue that, just like non-genetic CKD, modern dietary practices, lifestyle, and environmental exposures initiate and accelerate ADPKD progression. Evidence shows that carbohydrate overconsumption, hyperglycemia, and insulin resistance significantly impact renal health. Additionally, factors like dehydration, electrolyte imbalances, nephrotoxin exposure, gastrointestinal dysbiosis, and renal microcrystal formation exacerbate ADPKD. Conversely, carbohydrate restriction, ketogenic metabolic therapy (KMT), and antagonizing the lithogenic risk show promise in slowing ADPKD progression. Addressing disease triggers through dietary modifications and lifestyle changes offers a conservative, non-pharmacological strategy for disease modification in ADPKD. This comprehensive review underscores the urgency of integrating diet and lifestyle factors into the clinical management of ADPKD to mitigate disease progression, improve patient outcomes, and offer therapeutic choices that can be implemented worldwide at low or no cost to healthcare payers and patients.

Sex-specific molecular signature of mouse podocytes in homeostasis and in response to pharmacological challenge with rapamycin

BACKGROUND

Sex differences exist in the prevalence and progression of major glomerular diseases. Podocytes are the essential cell-type in the kidney which maintain the physiological blood-urine barrier, and pathological changes in podocyte homeostasis are critical accelerators of impairment of kidney function. However, sex-specific molecular signatures of podocytes under physiological and stress conditions remain unknown. This work aimed at identifying sexual dimorphic molecular signatures of podocytes under physiological condition and pharmacologically challenged homeostasis with mechanistic target of rapamycin (mTOR) inhibition. mTOR is a crucial regulator involved in a variety of physiological and pathological stress responses in the kidney and inhibition of this pathway may therefore serve as a general stress challenger to get fundamental insights into sex differences in podocytes.

METHODS

The genomic ROSAmT/mG-NPHS2 Cre mouse model was used which allows obtaining highly pure podocyte fractions for cell-specific molecular analyses, and vehicle or pharmacologic treatment with the mTOR inhibitor rapamycin was performed for 3 weeks. Subsequently, deep RNA sequencing and proteomics were performed of the isolated podocytes to identify intrinsic sex differences. Studies were supplemented with metabolomics from kidney cortex tissues.

RESULTS

Although kidney function and morphology remained normal in all experimental groups, RNA sequencing, proteomics and metabolomics revealed strong intrinsic sex differences in the expression levels of mitochondrial, translation and structural transcripts, protein abundances and regulation of metabolic pathways. Interestingly, rapamycin abolished prominent sex-specific clustering of podocyte gene expression and induced major changes only in male transcriptome. Several sex-biased transcription factors could be identified as possible upstream regulators of these sexually dimorphic responses. Concordant to transcriptomics, metabolomic changes were more prominent in males. Remarkably, high number of previously reported kidney disease genes showed intrinsic sexual dimorphism and/or different response patterns towards mTOR inhibition.

CONCLUSIONS

Our results highlight remarkable intrinsic sex-differences and sex-specific response patterns towards pharmacological challenged podocyte homeostasis which might fundamentally contribute to sex differences in kidney disease susceptibilities and progression. This work provides rationale and an in-depth database for novel targets to be tested in specific kidney disease models to advance with sex-specific treatment strategies.

The role of rapamycin in the PINK1/Parkin signaling pathway in mitophagy in podocytes

This study aimed to clarify the role of rapamycin in the PINK1/Parkin signaling pathway in mitophagy in podocytes and the role of voltage-dependent anion channel 1 (VDAC1) in the PINK1/Parkin signaling pathway in mouse glomerular podocytes. For this purpose, podocytes were cultured with rapamycin and observed using microscopy. The apoptosis rate of podocytes was detected by flow cytometry. Changes in the mitochondrial membrane potential were measured. The autophagy-related proteins VDAC1, PINK1, Parkin, and LC3 were detected, and mitochondrial autophagosomes were observed via transmission electron microscopy. In the present study, we demonstrated that the number of podocytes treated with rapamycin was significantly reduced. Compared with those in the control group, the apoptosis rate of podocytes and the degree of mitochondrial membrane potential depolarization were significantly higher. We also found the expression levels of VDAC1, PINK1, Parkin, and LC3 were significantly increased. In the rapamycin-treated group, the numbers of swollen mitochondria and mitochondrial autophagosomes were significantly higher. Finally, we showed that rapamycin can upregulate the expression of VDAC1, PINK1, Parkin, and LC3 in glomerular podocytes, which is correlated with mitophagy. VDAC1 is involved in mitophagy and is related to the PINK1/Parkin signaling pathway, serving as an indicator of mitophagy in podocytes.

Modern Challenges in Type 2 Diabetes: Balancing New Medications with Multifactorial Care

Type 2 diabetes mellitus (T2DM) is a prevalent chronic metabolic disorder characterized by insulin resistance and progressive beta cell dysfunction, presenting substantial global health and economic challenges. This review explores recent advancements in diabetes management, emphasizing novel pharmacological therapies and their physiological mechanisms. We highlight the transformative impact of Sodium-Glucose Cotransporter 2 inhibitor (SGLT2i) and Glucagon-Like Peptide 1 Receptor Agonist (GLP-1RA), which target specific physiological pathways to enhance glucose regulation and metabolic health. A key focus of this review is tirzepatide, a dual agonist of the glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptors. Tirzepatide illustrates how integrating innovative mechanisms with established physiological pathways can significantly improve glycemic control and support weight management. Additionally, we explore emerging treatments such as glimins and glucokinase activators (GKAs), which offer novel strategies for enhancing insulin secretion and reducing glucose production. We also address future perspectives in diabetes management, including the potential of retatrutide as a triple receptor agonist and evolving guidelines advocating for a comprehensive, multifactorial approach to care. This approach integrates pharmacological advancements with essential lifestyle modifications-such as dietary changes, physical activity, and smoking cessation-to optimize patient outcomes. By focusing on the physiological mechanisms of these new therapies, this review underscores their role in enhancing T2DM management and highlights the importance of personalized care plans to address the complexities of the disease. This holistic perspective aims to improve patient quality of life and long-term health outcomes.

mTOR and SGLT-2 Inhibitors: Their Synergistic Effect on Age-Related Processes

The aging process contributes significantly to the onset of chronic diseases, which are the primary causes of global mortality, morbidity, and healthcare costs. Numerous studies have shown that the removal of senescent cells from tissues extends lifespan and reduces the occurrence of age-related diseases. Consequently, there is growing momentum in the development of drugs targeting these cells. Among them, mTOR and SGLT-2 inhibitors have garnered attention due to their diverse effects: mTOR inhibitors regulate cellular growth, metabolism, and immune responses, while SGLT-2 inhibitors regulate glucose reabsorption in the kidneys, resulting in various beneficial metabolic effects. Importantly, these drugs may act synergistically by influencing senescence processes and pathways. Although direct studies on the combined effects of mTOR inhibition and SGLT-2 inhibition on age-related processes are limited, this review aims to highlight the potential synergistic benefits of these drugs in targeting senescence.

Potential Add-On Benefits of Dietary Intervention in the Treatment of Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of renal failure. The pathogenesis of the disease encompasses several pathways and metabolic alterations, including the hyperactivation of mTOR and suppression of AMPK signaling pathways, as well as mitochondrial dysfunction. This metabolic reprogramming makes epithelial cyst-lining cells highly dependent on glucose for energy and unable to oxidize fatty acids. Evidence suggests that high-carbohydrate diets may worsen the progression of ADPKD, providing the rationale for treating ADPKD patients with calorie restriction and, in particular, with ketogenic dietary interventions, already used for other purposes such as in overweight/obese patients or in the treatment of refractory epilepsy in children. Preclinical studies have demonstrated that calorie restriction may prevent and/or slow disease progression by inducing ketosis, particularly through increased beta-hydroxybutyrate (BHB) levels, which may modulate the metabolic signaling pathways altered in ADKPK. In these patients, although limited, ketogenic intervention studies have shown promising beneficial effects. However, larger and longer randomized controlled trials are needed to confirm their tolerability and safety in long-term maintenance and their additive role in the therapy of polycystic kidney disease.

Applications of SGLT2 inhibitors beyond glycaemic control

Sodium-glucose cotransporter 2 (SGLT2) inhibitors were initially developed for their glucose-lowering effects and have shown a modest glycaemic benefit in people with type 2 diabetes mellitus (T2DM). In the past decade, a series of large, robust clinical trials of these therapies have demonstrated striking beneficial effects for various care goals, transforming the chronic disease therapeutic landscape. Cardiovascular safety studies in people with T2DM demonstrated that SGLT2 inhibitors reduce cardiovascular death and hospitalization for heart failure. Subsequent trials in participants with heart failure with reduced or preserved left ventricular ejection fraction demonstrated that SGLT2 inhibitors have beneficial effects on heart failure outcomes. In dedicated kidney outcome studies, SGLT2 inhibitors reduced the incidence of kidney failure among participants with or without diabetes. Post hoc analyses have suggested a range of other benefits of these drugs in conditions as diverse as metabolic dysfunction-associated steatotic liver disease, kidney stone prevention and anaemia. SGLT2 inhibitors have a generally favourable adverse effect profile, although patient selection and medication counselling remain important. Concerted efforts are needed to better integrate these agents into routine care and support long-term medication adherence to close the gap between clinical trial outcomes and those achieved in the real world.