SGLT2 inhibitors may offer benefit beyond diabetes

Dapagliflozin exerts anti-apoptotic effects by mitigating macrophage polarization via modulation of the phosphoinositide 3-kinase/protein kinase B signaling pathway

BACKGROUND

Macrophages are central to the orchestration of immune responses, inflammatory processes, and the pathogenesis of diabetic complications. The dynamic polarization of macrophages into M1 and M2 phenotypes critically modulates inflammation and contributes to the progression of diabetic nephropathy. Sodium-glucose cotransporter 2 inhibitors such as dapagliflozin, which are acclaimed for their efficacy in diabetes management, may influence macrophage polarization, thereby ameliorating diabetic nephropathy. This investigation delves into these mechanistic pathways, aiming to elucidate novel therapeutic strategies for diabetes.

AIM

To investigate the inhibitory effect of dapagliflozin on macrophage M1 polarization and apoptosis and to explore its mechanism of action.

METHODS

We established a murine model of type 2 diabetes mellitus and harvested peritoneal macrophages following treatment with dapagliflozin. Concurrently, the human monocyte cell line cells were used for in vitro studies. Macrophage viability was assessed in a cell counting kit 8 assay, whereas apoptosis was evaluated by Annexin V/propidium iodide staining. Protein expression was examined through western blotting, and the expression levels of macrophage M1 surface markers, inflammatory cytokines, and apoptotic factors were quantified using flow cytometry, enzyme linked immunosorbent assay, and quantitative real-time polymerase chain reaction analyses.

RESULTS

Dapagliflozin attenuated M1 macrophage polarization and mitigated apoptosis in the abdominal macrophages of diabetic mice, evidenced by the downregulation of proapoptotic genes (Caspase 3), inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor-α, and IL-1β], and M1 surface markers (inducible nitric oxide synthase, and cluster of differentiation 86), as well as the upregulation of the antiapoptotic gene BCL2. Moreover, dapagliflozin suppressed the expression of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway (PI3K, AKT, phosphorylated protein kinase B). These observations were corroborated in vitro, where we found that the modulatory effects of dapagliflozin were abrogated by 740Y-P, an activator of the PI3K/AKT signaling pathway.

CONCLUSION

Dapagliflozin attenuates the polarization of macrophages toward the M1 phenotype, thereby mitigating inflammation and promoting macrophage apoptosis. These effects are likely mediated through the inhibition of the PI3K/AKT signaling pathway.

Design, synthesis and biological evaluation of novel oxazole derivatives as potential hypoglycemic agents

A series of 2,4-disubstituted-oxazole derivatives have been designed and synthesized based on compound 3a, a promising lead compound developed in our lab. Among these derivatives, the optimized compound 5k exhibited potent hypoglycemic activity, increasing glucose consumption by 60 % in HepG2 cells compared to the solvent control, and its activity was higher than that of metformin. Further investigation indicated that compound 5k exhibited negligible cytotoxic effects at a concentration of 25 μM in HepG2 and 3T3-L1 cells and showed moderate inhibitory activity against various subtypes of human cytochrome P450 subtypes. An oral glucose tolerance test confirmed that 5k is an effective hypoglycemic agent. Additionally, mechanistic studies suggested that 5k may exert its hypoglycemic activity through the activation of the AMPK pathway.

Megalin Knockout Reduces SGLT2 Expression and Sensitizes to Western Diet-induced Kidney Injury

Megalin (Lrp2) is a multiligand receptor that drives endocytic flux in the kidney proximal tubule (PT) and is necessary for the recovery of albumin and other filtered proteins that escape the glomerular filtration barrier. Studies in our lab have shown that knockout (KO) of Lrp2 in opossum PT cells leads to a dramatic reduction in sodium-glucose co-transporter 2 (SGLT2) transcript and protein levels, as well as differential expression of genes involved in mitochondrial and metabolic function. SGLT2 transcript levels are reduced more modestly in Lrp2 KO mice. Here, we investigated the effects of Lrp2 KO on kidney function and health in mice fed regular chow (RC) or a Western-style diet (WD) high in fat and refined sugar. Despite a modest reduction in SGLT2 expression, Lrp2 KO mice on either diet showed increased glucose tolerance compared to control mice. Moreover, Lrp2 KO mice were protected against WD-induced fat gain. Surprisingly, renal function in male Lrp2 KO mice on WD was compromised, and the mice exhibited significant kidney injury compared with control mice on WD. Female Lrp2 KO mice were less susceptible to WD-induced kidney injury than male Lrp2 KO. Together, our findings reveal both positive and negative contributions of megalin expression to metabolic health, and highlight a megalin-mediated sex-dependent response to injury following WD.

The role and therapeutic potential of macrophages in the pathogenesis of diabetic cardiomyopathy

This review provides a comprehensive analysis of the critical role played by macrophages and their underlying mechanisms in the progression of diabetic cardiomyopathy (DCM). It begins by discussing the origins and diverse subtypes of macrophages, elucidating their spatial distribution and modes of intercellular communication, thereby emphasizing their significance in the pathogenesis of DCM. The review then delves into the intricate relationship between macrophages and the onset of DCM, particularly focusing on the epigenetic regulatory mechanisms employed by macrophages in the context of DCM condition. Additionally, the review discusses various therapeutic strategies aimed at targeting macrophages to manage DCM. It specifically highlights the potential of natural food components in alleviating diabetic microvascular complications and examines the modulatory effects of existing hypoglycemic drugs on macrophage activity. These findings, summarized in this review, not only provide fresh insights into the role of macrophages in diabetic microvascular complications but also offer valuable guidance for future therapeutic research and interventions in this field.

Effect of sodium-glucose cotransporter-2 inhibitors on myocardial infarction incidence: A systematic review and meta-analysis of randomized controlled trials and cohort studies

AIM

To assess whether sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce myocardial infarction (MI) incidence in patients with or without type 2 diabetes.

METHODS

PubMed, Embase, Web of Science, the Cochrane library, and https://ClinicalTrials.gov were searched up to 7 May 2022. Randomized controlled trials (RCTs) and cohort studies reporting the effects of SGLT2 inhibitor treatment on MI incidence were included. Relative risks (RRs) with a 95% confidence interval (CI) for MI incidence were extracted and pooled. Subgroup analysis and meta-regression were performed to explore the heterogeneity.

RESULTS

This meta-analysis included 54 RCTs and 32 cohort studies, with data from six SGLT2 inhibitors and 3 394 423 individuals. In the overall analysis, SGLT2 inhibitors significantly reduced MI incidence in RCTs (RR 0.9, 95% CI 0.84-0.96) and cohort studies (RR 0.89, 95% CI 0.83-0.94). In RCTs, the results of the subgroup analysis revealed no significant alterations in outcomes based on different SGLT2 inhibitor types, control drug types, cardiovascular disease (CVD) status and sources of outcome extraction (p for interaction >0.05). In cohort studies, the presence or absence of CVD led to similar effects of SGLT2 inhibitors on decreasing MI incidence (p for interaction = 0.179). However, variations in results were observed based on the type of control group in cohort studies (p for interaction = 0.036). Meta-regression results did not reveal an association between baseline cardiovascular risk factors, follow-up length, or MI incidence.

CONCLUSIONS

In both RCTs and cohort studies, SGLT2 inhibitors reduced MI incidence. The cardioprotective effects of SGLT2 inhibitors were observed in patients with and without a history of CVD.

Comparison of Effectiveness Among Different Sodium-Glucose Cotransoporter-2 Inhibitors According to Underlying Conditions: A Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

To investigate the individual profile of each SGLT2 (sodium-glucose cotransoporter-2) inhibitor in patients with different backgrounds.

METHODS AND RESULTS

This study included 21 placebo-controlled randomized controlled trials with a total of 96 196 participants, investigating empagliflozin, ertugliflozin, dapagliflozin, canagliflozin, and sotagliflozin. The primary efficacy end point was the composite of cardiovascular death and hospitalizations for heart failure. The secondary efficacy end points were all-cause death, cardiovascular death, hospitalizations for heart failure, kidney disease progression, and acute kidney injury. We conducted subgroup analyses based on the underlying comorbidities, including diabetes and chronic kidney disease. Safety end points were also assessed among SGLT2 inhibitors in the overall cohort. In the overall cohort, there were no significant differences in the primary efficacy outcome among the SGLT2 inhibitors, while empagliflozin (hazard ratio [HR], 0.70 [95% CI, 0.53-0.92]) and dapagliflozin (HR, 0.73 [95% CI, 0.56-0.96]) were associated with lower risk of acute kidney injury than sotagliflozin. The presence or absence of diabetes did not alter the results. In patients with chronic kidney disease, there were no differences in the efficacy outcomes among SGLT2 inhibitors, while in patients without chronic kidney disease, empagliflozin was associated with lower risk of the primary outcome compared with ertugliflozin (HR, 0.77 [95% CI, 0.60-0.98]). For safety outcomes, no significant differences were observed in amputation, urinary tract infection, genital infection, hypoglycemia, and diabetic ketoacidosis.

CONCLUSIONS

The differences in reducing cardiovascular and kidney outcomes as well as safety profiles across SGLT2 inhibitors were not consistently significant, although empagliflozin might be preferred in patients without chronic kidney disease. Further investigations are needed to better understand the mechanism and clinical effectiveness of each SGLT2 inhibitor in certain populations.

Sodium-Glucose Cotransporter Protein 2 Inhibitors: Novel Application for the Treatment of Obesity-Associated Hypertension

Obesity is becoming increasingly prevalent in China and worldwide and is closely related to the development of hypertension. The pathophysiology of obesity-associated hypertension is complex, including an overactive sympathetic nervous system (SNS), activation of the renin-angiotensin-aldosterone system (RAAS), insulin resistance, hyperleptinemia, renal dysfunction, inflammatory responses, and endothelial function, which complicates treatment. Sodium-glucose cotransporter protein 2 (SGLT-2) inhibitors, novel hypoglycemic agents, have been shown to reduce body weight and blood pressure and may serve as potential novel agents for the treatment of obesity-associated hypertension. This review discusses the beneficial mechanisms of SGLT-2 inhibitors for the treatment of obesity-associated hypertension. SGLT-2 inhibitors can inhibit SNS activity, reduce RAAS activation, ameliorate insulin resistance, reduce leptin secretion, improve renal function, and inhibit inflammatory responses. SGLT-2 inhibitors can, therefore, simultaneously target multiple mechanisms of obesity-associated hypertension and may serve as an effective treatment for obesity-associated hypertension.

Site-Selective C-O Bond Editing of Unprotected Saccharides

Glucose and its polyhydroxy saccharide analogs are complex molecules that serve as essential structural components in biomacromolecules, natural products, medicines, and agrochemicals. Within the expansive realm of saccharides, a significant area of research revolves around chemically transforming naturally abundant saccharide units to intricate or uncommon molecules such as oligosaccharides or rare sugars. However, partly due to the presence of multiple hydroxyl groups with similar reactivities and the structural complexities arising from stereochemistry, the transformation of unprotected sugars to the desired target molecules remains challenging. One such formidable challenge lies in the efficient and selective activation and modification of the C-O bonds in saccharides. In this study, we disclose a modular 2-fold "tagging-editing" strategy that allows for direct and selective editing of C-O bonds of saccharides, enabling rapid preparation of valuable molecules such as rare sugars and drug derivatives. The first step, referred to as "tagging", involves catalytic site-selective installation of a photoredox active carboxylic ester group to a specific hydroxyl unit of an unprotected sugar. The second step, namely, "editing", features a C-O bond cleavage to form a carbon radical intermediate that undergoes further transformations such as C-H and C-C bond formations. Our strategy constitutes the most effective and shortest route in direct transformation and modification of medicines and other molecules bearing unprotected sugars.

Role of Erythropoiesis-Stimulating Agents in Cardiovascular Protection in CKD Patients: Reappraisal of Their Impact and Mechanisms

Erythropoiesis-stimulating agents (ESAs) have markedly reduced the need for blood transfusion for renal anemia and are included in standard therapies for patients with chronic kidney disease (CKD). Various protective effects of ESAs on the cardiovascular system have been discovered through basic research, and the effects have received much attention because the rates of cardiovascular events and mortality are high in CKD patients. However, randomized clinical trials did not provide strong evidence that ESAs exert cardioprotection in humans, including CKD patients. It is difficult to assess the cardioprotective effects of ESAs in CKD patients through the clinical data that has been reported to date because the relationship between hemoglobin level rather than ESA dose and cardiovascular event rates was examined in most studies. Interestingly, recent studies using a rat model of CKD showed that the infarct size-limiting effect of an ESA was lost when its dose was increased to a level that normalized blood hemoglobin levels, suggesting that the optimal dose of an ESA for myocardial protection is less than the dose required to normalize hemoglobin levels. Furthermore, animal models of traditional coronary risk factors or comorbidities were resistant to the cardioprotective effects of ESAs because of interruptions in signal-mediated mechanisms downstream of erythropoietin receptors. In this review, we briefly discuss basic and clinical data on the impact of anemia on coronary and systemic circulation, the effects of CKD on the cardiovascular system, and the multiple pharmacological actions of ESAs to examine whether the ESAs that are prescribed for renal anemia exert any cardioprotection in patients with CKD.

The SGLT2 Inhibitor Canagliflozin Reduces Atherosclerosis by Enhancing Macrophage Autophagy

It has been shown that SGLT2 suppresses atherosclerosis (AS). Recent studies indicate that autophagy widely participates in atherogenesis. This study aimed to assess the effect of canagliflozin (CAN) on atherogenesis via autophagy. Macrophages and ApoE - / - mice were used in this study. In macrophages, the results showed that CAN promoted LC3II expression and autophagosome formation. Furthermore, the cholesterol efflux assay demonstrated that CAN enhanced cholesterol efflux from macrophages via autophagy, resulting in lower lipid droplet concentrations in macrophages. The western blot revealed that CAN regulated autophagy via the AMPK/ULK1/Beclin1 signaling pathway. CAN resulted in increased macrophage autophagy in atherosclerotic plaques of ApoE - / - mice, confirming that CAN could inhibit the progression of AS via promoting macrophage autophagy. The current study found that CAN reduced the production of atherosclerotic lesions, which adds to our understanding of how SGLT2 inhibitors function to delay the progression of AS.

Outcomes of Prediabetes Compared with Normoglycaemia and Diabetes Mellitus in Patients Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-analysis

Background: Patients with prediabetes are at increased risk of coronary artery disease (CAD). However, the association between prediabetes and adverse clinical outcomes following percutaneous coronary intervention (PCI) is inconsistent, in contrast to outcomes in patients with diabetes mellitus (DM). Thus, this meta-analysis evaluated the impact of dysglycaemia on PCI outcomes. Methods: The PubMed, Embase, Cochrane, and ClinicalTrials.gov databases were systematically reviewed from inception of databases until June 2022. In 17 studies, outcomes of PCI in patients with prediabetes were compared with patients who were normoglycaemic, and patients with DM. The primary outcome was all-cause mortality at the longest follow-up. Results: Included were 12 prospective and five retrospective studies, with 11,868, 14,894 and 13,536 patients undergoing PCI in the prediabetes, normoglycaemic and DM groups, respectively. Normoglycaemic patients had a statistically lower risk of all-cause mortality, (risk ratio [RR] 0.66, 95% confidence interval [CI] 0.52-0.84), myocardial infarction (MI; RR 0.76, 95% CI 0.61-0.95) and cardiac mortality (RR 0.58, 95% CI 0.39-0.87) compared with prediabetic patients undergoing PCI at the longest follow-up. Patients with prediabetes had a lower risk of all-cause mortality (RR=0.72 [95% CI 0.53-0.97]) and cardiac mortality (RR =0.47 [95% CI 0.23-0.93]) compared with patients with DM who underwent PCI. Conclusion: Among patients who underwent PCI for CAD, the risk of all-cause and cardiac mortality, major adverse cardiovascular events and MI in prediabetic patients was higher compared with normoglycaemic patients but lower compared with patients with DM.

An international Delphi consensus statement on metabolic dysfunction-associated fatty liver disease and risk of chronic kidney disease

BACKGROUND

With the rising global prevalence of fatty liver disease related to metabolic dysfunction, the association of this common liver condition with chronic kidney disease (CKD) has become increasingly evident. In 2020, the more inclusive term metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed to replace the term non-alcoholic fatty liver disease (NAFLD). The observed association between MAFLD and CKD and our understanding that CKD can be a consequence of underlying metabolic dysfunction support the notion that individuals with MAFLD are at higher risk of having and developing CKD compared with those without MAFLD. However, to date, there is no appropriate guidance on CKD in individuals with MAFLD. Furthermore, there has been little attention paid to the link between MAFLD and CKD in the Nephrology community.

METHODS AND RESULTS

Using a Delphi-based approach, a multidisciplinary panel of 50 international experts from 26 countries reached a consensus on some of the open research questions regarding the link between MAFLD and CKD.

CONCLUSIONS

This Delphi-based consensus statement provided guidance on the epidemiology, mechanisms, management and treatment of MAFLD and CKD, as well as the relationship between the severity of MAFLD and risk of CKD, which establish a framework for the early prevention and management of these two common and interconnected diseases.

SGLT-2 Inhibitors and the Inflammasome: What's Next in the 21st Century?

The nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome in the kidney and the heart is increasingly being suggested to play a key role in mediating inflammation. In the kidney, NLRP3 activation was associated with the progression of diabetic kidney disease. In the heart, activation of the NLRP3 inflammasome was related to the enhanced release of interleukin-1β (IL-1β) and the subsequent induction of atherosclerosis and heart failure. Apart from their glucose-lowering effects, SGLT-2 inhibitors were documented to attenuate activation of the NLRP3, thus resulting in the constellation of an anti-inflammatory milieu. In this review, we focus on the interplay between SGLT-2 inhibitors and the inflammasome in the kidney, the heart and the neurons in the context of diabetes mellitus and its complications.

Incorporating Evidence and Guidelines for Personalized Care of Diabetes and Chronic Kidney Disease

Chronic kidney disease (CKD) represents a particularly challenging diabetes complication. Diabetes now is responsible for half of all cases of CKD, thus making diabetes the most common cause of kidney failure worldwide. In patients with diabetes, CKD frequently coexists with heart failure and atherosclerotic cardiovascular disease, which together are associated with marked increases in the risk of cardiovascular and all-cause mortality. Fortunately, new therapeutic agents from several classes now are available with proven benefits for kidney and heart protection when used in patients with type 2 diabetes and CKD. Agents from the sodium-glucose cotransporter-2 inhibitor, glucagon-like peptide-1-receptor agonist, and nonsteroidal mineralocorticoid-receptor antagonist classes now are considered standard of care to improve kidney, heart, and overall survival outcomes in patients with type 2 diabetes. Efforts to educate health care providers on the benefits of these therapies are critically needed to help increase their utilization and improve clinical outcomes. Care decisions should be driven by a holistic view of patient priorities and goals with consideration of a multimodal therapeutic approach to maximize heart and kidney benefits.

Emerging Role of Sodium-Glucose Co-Transporter 2 Inhibitors for the Treatment of Chronic Kidney Disease

Chronic kidney disease is one of the leading causes of morbidity and mortality in the Philippines. It is associated with a growing health burden as many patients progress to end-stage renal disease. Until recently, therapeutic options for the management of chronic kidney disease were limited. Sodium-glucose co-transporter 2 inhibitors offer an alternative therapeutic approach for patients with chronic kidney disease. Several trials have shown renal benefits with sodium-glucose co-transporter 2 inhibitors in patients with cardiovascular disease with and without type 2 diabetes and across a range of estimated glomerular filtration rate levels. In the Philippines, the sodium-glucose co-transporter 2 inhibitors dapagliflozin and canagliflozin are approved for the prevention of new and worsening nephropathy in type 2 diabetes. With emerging treatment options, an urgent need exists for guidance on the management of chronic kidney disease within the Philippines. In this review, we focus on the putative renal-protective mechanisms of sodium-glucose co-transporter 2 inhibitors, including effects on tubuloglomerular feedback, albuminuria, endothelial function, erythropoiesis, uric acid levels, renal oxygen demand, and hypoxia. Furthermore, we discuss the findings of recent large clinical trials using sodium-glucose co-transporter 2 inhibitors in patients with chronic kidney disease and diabetic kidney disease, summarize safety aspects, and outline the practical management of patients with chronic kidney disease in the Philippines.

Value of SGLT-2 inhibitors in the treatment of chronic kidney disease : Clinical and practical implications

Chronic kidney disease (CKD) drastically increases the risk for cardiovascular morbidity and mortality and its worldwide prevalence is still rising. Effective treatment slows CKD progression, prevents development of end-stage kidney disease and cardiovascular disease thereby prolonging survival of patients. Recently, several large-scale studies with sodium-glucose cotransport‑2 inhibitors (SGLT-2i) have demonstrated profound nephroprotective and cardioprotective properties in patients with type 2 diabetes mellitus with both CKD and heart failure. Recently, the dapagliflozin and prevention of adverse outcomes in chronic kidney disease (DAPA-CKD) trial demonstrated that the selective SGLT-2i dapagliflozin reduced the hazard ratio for a composite renal and cardiovascular death endpoint in patients with CKD with or without type 2 diabetes. Furthermore, dapagliflozin exerted strong nephroprotection in CKD patients with diverse etiologies like IgA nephropathy. Furthermore, other promising CKD trials such as with empagliflozin are underway. Hence, individualized treatment with SGLT2i represents a promising therapeutic option for patients with both diabetic and non-diabetic CKD. Here we summarize the current knowledge on the treatment with SGLT-2i in CKD patients underscoring a strong rationale for SGLT2 inhibition to be incorporated into standard of care for most CKD patients also with non-diabetic kidney disease. Finally, we aim to translate the current evidence into recommendations for the clinical practice in the management of patients with CKD.

Biomolecular Mechanisms of Cardiorenal Protection with Sodium-Glucose Co-Transporter 2 Inhibitors

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia and associated with an increased risk of morbidity and mortality, primarily from cardiovascular and renal diseases. Sodium-glucose cotransporter 2 inhibitors (SGLT2-Is) are novel drugs for the treatment of type 2 DM and heart failure (HF). SGLT2-Is mediate protective effects on both the renal and cardiovascular systems. This review addresses the current knowledge on the biomolecular mechanisms of the cardiorenal protective effects of SGLT2-Is, which appear to act mainly through non-glucose-mediated pathways. Cardiorenal protection mechanisms lead to reduced chronic renal disease progression and improved myocardial and coronary endothelial function. Concomitantly, it is possible to observe reflected changes in biomarkers linked with diabetic kidney disease and HF.

Canagliflozin Ameliorates Nonalcoholic Fatty Liver Disease by Regulating Lipid Metabolism and Inhibiting Inflammation through Induction of Autophagy

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is closely associated with metabolic diseases, including obesity and diabetes, and has gradually become the most common cause of chronic liver disease. We investigated the effects of sodium glucose cotransporter 2 (SGLT2) inhibitor canagliflozin on NAFLD in high-fat diet (HFD)-induced obese mice and possible underlying mechanisms.

MATERIALS AND METHODS

Male C57BL/6 mice were fed a normal-diet, HFD, or HFD with canagliflozin for 14 weeks. AML-12 hepatocytes were treated with canagliflozin. Expression of related pathways was assessed.

RESULTS

Canagliflozin administration reduced body weight and fat mass, compared with HFD alone. Canagliflozin improved glucose and lipid metabolic disorders. Compared with HFD-fed mice, liver weight, serum alanine transaminase (ALT) levels, and hepatic lipid accumulation were decreased after canagliflozin administration. Additionally, canagliflozin upregulated lipolysis markers (CPT1a, ACOX1, and ACADM), downregulated lipogenesis markers (SREBP-1c and FASN), and suppressed the production of inflammatory cytokines (TNFα, MCP1, IL-1β, and IL-6), consistent with significantly increased LC3 II/I and Atg7 levels in the liver following canagliflozin treatment. In vitro, canagliflozin increased CPT1a, ACOX1, and ACADM expression, decreased SREBP-1c and FASN protein expression, and reduced TNFα, MCP1, IL-1β, and IL-6 mRNA levels in lipid mixture (LM)-induced hepatocytes in a dose-dependent manner. These changes were reversed by 3-MA, an autophagy inhibitor.

CONCLUSION

Our findings suggest that canagliflozin ameliorates the pathogenesis of NAFLD by regulating lipid metabolism and inhibiting inflammation, which may be associated with its promotion of autophagy.

Molecular Mechanisms and Therapeutic Targets for Diabetic Kidney Disease

Diabetic kidney disease has a high global disease burden and substantially increases risk of kidney failure and cardiovascular events. Despite treatment, there is substantial residual risk of disease progression with existing therapies. Therefore, there is an urgent need to better understand the molecular mechanisms driving diabetic kidney disease to help identify new therapies that slow progression and reduce associated risks. Diabetic kidney disease is initiated by diabetes-related disturbances in glucose metabolism, which then trigger other metabolic, hemodynamic, inflammatory, and fibrotic processes that contribute to disease progression. This review summarizes existing evidence on the molecular drivers of diabetic kidney disease onset and progression, focusing on inflammatory and fibrotic mediators-factors that are largely unaddressed as primary treatment targets and for which there is increasing evidence supporting key roles in the pathophysiology of diabetic kidney disease. Results from recent clinical trials highlight promising new drug therapies, as well as a role for dietary strategies, in treating diabetic kidney disease.

Association Between the Use of Sodium-Glucose Cotransporter-2 Inhibitors and Drug-Induced Acute Kidney Injury: Analysis of 2 Databases

The association between the use of sodium-glucose cotransporter-2 (SGLT-2) inhibitors and the occurrence of drug-induced kidney injury has not been evaluated. This study assessed whether the use of SGLT-2 inhibitors decreases the risk of drug-induced acute kidney injury (AKI) using the US Food and Drug Administration's Adverse Event Reporting System and the Medical Data Vision database. The occurrence of AKI in SGLT-2 inhibitor users and dipeptidyl peptidase-4 (DPP-4) inhibitor users was compared using both databases. In the US Food and Drug Administration's Adverse Event Reporting System analysis, disproportionality for AKI was observed between DPP-4 inhibitor users and SGLT-2 inhibitor users administered nonsteroidal anti-inflammatory drugs (reporting odds ratio, 0.65; 95%CI, 0.48-0.88; P < .01) and thiazide diuretics (reporting odds ratio, 0.78; 95%CI, 0.67-0.90; P < .01). In Medical Data Vision analysis, SGLT-2 inhibitor users administered nonsteroidal anti-inflammatory drugs (odds ratio [OR], 0.46; 95%CI, 0.41-0.53; P < .01), anti-herpes simplex virus drugs (OR, 0.20; 95%CI, 0.07-0.53; P < .01), thiazide diuretics (OR, 0.50; 95%CI, 0.36-0.71, P < .01), and loop diuretics (OR, 0.71; 95%CI, 0.62-0.83; P < .01) had a lower incidence of AKI compared with DPP-4 inhibitor users receiving the same drugs. No differences were observed in the risk of AKI between SGLT-2 and DPP-4 inhibitor users administered vancomycin and cisplatin in both databases. The use of SGLT-2 inhibitors might reduce the risk of drug-induced AKI caused by some drugs.

Association of metabolic dysfunction-associated fatty liver disease with kidney disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of fat in more than 5% of hepatocytes in the absence of excessive alcohol consumption and other secondary causes of hepatic steatosis. In 2020, the more inclusive term metabolic (dysfunction)-associated fatty liver disease (MAFLD) - defined by broader diagnostic criteria - was proposed to replace the term NAFLD. The new terminology and revised definition better emphasize the pathogenic role of metabolic dysfunction and uses a set of definitive, inclusive criteria for diagnosis. Diagnosis of MAFLD is based on evidence of hepatic steatosis (as assessed by liver biopsy, imaging techniques or blood biomarkers and scores) in persons who are overweight or obese and have type 2 diabetes mellitus or metabolic dysregulation, regardless of the coexistence of other liver diseases or excessive alcohol consumption. The known association between NAFLD and chronic kidney disease (CKD) and our understanding that CKD can occur as a consequence of metabolic dysfunction suggests that individuals with MAFLD - who by definition have fatty liver and metabolic comorbidities - are at increased risk of CKD. In this Perspective article, we discuss the clinical associations between MAFLD and CKD, the pathophysiological mechanisms by which MAFLD may increase the risk of CKD and the potential drug treatments that may benefit both conditions.

An Overview of the Cardiorenal Protective Mechanisms of SGLT2 Inhibitors

Sodium-glucose co-transporter 2 (SGLT2) inhibitors block glucose reabsorption in the renal proximal tubule, an insulin-independent mechanism that plays a critical role in glycemic regulation in diabetes. In addition to their glucose-lowering effects, SGLT2 inhibitors prevent both renal damage and the onset of chronic kidney disease and cardiovascular events, in particular heart failure with both reduced and preserved ejection fraction. These unexpected benefits prompted changes in treatment guidelines and scientific interest in the underlying mechanisms. Aside from the target effects of SGLT2 inhibition, a wide spectrum of beneficial actions is described for the kidney and the heart, even though the cardiac tissue does not express SGLT2 channels. Correction of cardiorenal risk factors, metabolic adjustments ameliorating myocardial substrate utilization, and optimization of ventricular loading conditions through effects on diuresis, natriuresis, and vascular function appear to be the main underlying mechanisms for the observed cardiorenal protection. Additional clinical advantages associated with using SGLT2 inhibitors are antifibrotic effects due to correction of inflammation and oxidative stress, modulation of mitochondrial function, and autophagy. Much research is required to understand the numerous and complex pathways involved in SGLT2 inhibition. This review summarizes the current known mechanisms of SGLT2-mediated cardiorenal protection.

Sodium/glucose cotransporter 2 (SGLT2) inhibitors improve cardiac function by reducing JunD expression in human diabetic hearts

BACKGROUND

The pathogenesis of experimental diabetic cardiomyopathy may involve the activator protein 1 (AP-1) member, JunD. Using non-diabetic heart transplant (HTX) in recipients with diabetes, we examined the effects of the diabetic milieu (hyperglycemia and insulin resistance) on cardiac JunD expression over 12 months. Because sodium/glucose cotransporter-2 inhibitors (SGLT2i) significantly reverse high glucose-induced AP-1 binding in the proximal tubular cell, we investigated JunD expression in a subgroup of type 2 diabetic recipients receiving SGLT2i treatment.

METHODS

We evaluated 77 first HTX recipients (40 and 37 patients with and without diabetes, respectively). Among the recipients with diabetes, 17 (45.9%) were receiving SGLT2i treatment. HTX recipients underwent standard clinical evaluation (metabolic status, echocardiography, coronary computed tomography angiography, and endomyocardial biopsy). In the biopsy samples, we evaluated JunD, insulin receptor substrates 1 and 2 (IRS1 and IRS2), peroxisome proliferator-activated receptor-γ (PPAR-γ), and ceramide levels using real-time polymerase chain reaction and immunofluorescence. The biopsy evaluations in this study were performed at 1-4 weeks (basal), 5-12 weeks (intermediate), and up to 48 weeks (final, end of 12-month follow-up) after HTX.

RESULTS

There was a significant early and progressive increase in the cardiac expression of JunD/PPAR-γ and ceramide levels, along with a significant decrease in IRS1 and IRS2 in recipients with diabetes but not in those without diabetes. These molecular changes were blunted in patients with diabetes receiving SGLT2i treatment.

CONCLUSION

Early pathogenesis in human diabetic cardiomyopathy is associated with JunD/PPAR-γ overexpression and lipid accumulation following HTX in recipients with diabetes. Remarkably, this phenomenon was reduced by concomitant therapy with SGLT2i, which acted directly on diabetic hearts.

Lipoproteins and fatty acids in chronic kidney disease: molecular and metabolic alterations

Chronic kidney disease (CKD) induces modifications in lipid and lipoprotein metabolism and homeostasis. These modifications can promote, modulate and/or accelerate CKD and secondary cardiovascular disease (CVD). Lipid and lipoprotein abnormalities - involving triglyceride-rich lipoproteins, LDL and/or HDL - not only involve changes in concentration but also changes in molecular structure, including protein composition, incorporation of small molecules and post-translational modifications. These alterations modify the function of lipoproteins and can trigger pro-inflammatory and pro-atherogenic processes, as well as oxidative stress. Serum fatty acid levels are also often altered in patients with CKD and lead to changes in fatty acid metabolism - a key process in intracellular energy production - that induce mitochondrial dysfunction and cellular damage. These fatty acid changes might not only have a negative impact on the heart, but also contribute to the progression of kidney damage. The presence of these lipoprotein alterations within a biological environment characterized by increased inflammation and oxidative stress, as well as the competing risk of non-atherosclerotic cardiovascular death as kidney function declines, has important therapeutic implications. Additional research is needed to clarify the pathophysiological link between lipid and lipoprotein modifications, and kidney dysfunction, as well as the genesis and/or progression of CVD in patients with kidney disease.

Key metalloproteinase-mediated pathways in the kidney

Matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs) belong to the metzincin family of zinc-containing multidomain molecules, and can act as soluble or membrane-bound proteases. These enzymes inactivate or activate other soluble or membrane-expressed mediator molecules, which enables them to control developmental processes, tissue remodelling, inflammatory responses and proliferative signalling pathways. The dysregulation of MMPs and ADAMs has long been recognized in acute kidney injury and in chronic kidney disease, and genetic targeting of selected MMPs and ADAMs in different mouse models of kidney disease showed that they can have detrimental and protective roles. In particular, MMP-2, MMP-7, MMP-9, ADAM10 and ADAM17 have been shown to have a mainly profibrotic effect and might therefore represent therapeutic targets. Each of these proteases has been associated with a different profibrotic pathway that involves tissue remodelling, Wnt-β-catenin signalling, stem cell factor-c-kit signalling, IL-6 trans-signalling or epidermal growth factor receptor (EGFR) signalling. Broad-spectrum metalloproteinase inhibitors have been used to treat fibrotic kidney diseases experimentally but more targeted approaches have since been developed, including inhibitory antibodies, to avoid the toxic side effects initially observed with broad-spectrum inhibitors. These advances not only provide a solid foundation for additional preclinical studies but also encourage further translation into clinical research.

Design, synthesis and evaluation of tetrahydrocarbazole derivatives as potential hypoglycemic agents

Two series of tetrahydrocarbazole derivatives have been designed and synthesized based on ZG02, a promising candidate developed in our previous studies. The newly prepared compounds were screened for glucose consumption activity in HepG2 cell lines. Aza-tetrahydrocarbazole compound 12b showed the most potent hypoglycemic activity with a 45% increase in glucose consumption when compared to the solvent control, which had approximately 1.2-fold higher activity than the positive control compounds (metformin and ZG02). An investigation of the potential mechanism indicated that 12b may exhibit hypoglycemic activity via activation of the AMPK pathway. Metabolic stability assays revealed that 12b showed good stability profiles in both artificial gastrointestinal fluids and blood plasma from SD rats. An oral glucose tolerance test (OGTT) was performed and the results further confirmed that 12b was a potent hypoglycemic agent.

SGLT2 inhibitors break the vicious circle between heart failure and insulin resistance: targeting energy metabolism

Heart failure (HF) often coexists with insulin resistance (IR), and the incidence of HF in type 2 diabetes mellitus (T2DM) patients is significantly higher. The reciprocal relationship between HF and IR has long been recognized, and the integration complicates the therapy of both. A number of mechanisms ascribe to the progression of cardiac IR, in which the main factors are the shift of myocardial substrate metabolism. Studies have found that SGLT2 inhibitors, an anti-diabetic drug, can improve the cardiac prognosis of patients with T2DM, which may be at least partially due to the relief of cardiac IR. Basic and clinical studies have revealed the important role of cardiac IR in the pathogenesis and progression of HF, and studies suggest that energy metabolism plays an important role in the pathogenesis of cardiac IR and HF. SGLT2 inhibitors mediated cardiovascular benefits through various mechanisms such as improving substrate utilization and improving myocardial energy. The regulation of SGLT2 inhibitors on cardiac energy status including carbohydrates, fatty acids (FA), amino acids and ketones, ATP transfer to the cytoplasm, and mitochondrial functional status have received extensive attention in HF, but its specific mechanism of action is still unclear. Therefore, this article reviews the relationship between IR and HF from the perspective of energy metabolism; subsequently, targeting energy metabolism discusses the pivotal role of SGLT2 inhibitors in improving cardiac IR and HF based on basic and clinical research evidences, and sought to clarify the molecular mechanism involved. (Fig. 1).