Antioxidant Roles of SGLT2 Inhibitors in the Kidney

The reduction-oxidation (redox) system consists of the coupling and coordination of various electron gradients that are generated thanks to serial reduction-oxidation enzymatic reactions. These reactions happen in every cell and produce radical oxidants that can be mainly classified into reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS modulate cell-signaling pathways and cellular processes fundamental to normal cell function. However, overproduction of oxidative species can lead to oxidative stress (OS) that is pathological. Oxidative stress is a main contributor to diabetic kidney disease (DKD) onset. In the kidney, the proximal tubular cells require a high energy supply to reabsorb proteins, metabolites, ions, and water. In a diabetic milieu, glucose-induced toxicity promotes oxidative stress and mitochondrial dysfunction, impairing tubular function. Increased glucose level in urine and ROS enhance the activity of sodium/glucose co-transporter type 2 (SGLT2), which in turn exacerbates OS. SGLT2 inhibitors have demonstrated clear cardiovascular benefits in DKD which may be in part ascribed to the generation of a beneficial equilibrium between oxidant and antioxidant mechanisms.

The Efficacy of Tofogliflozin on Metabolic Dysfunction-Associated Fatty Liver Disease

The increasing number of patients with fatty liver disease is a major health problem. Fatty liver disease with metabolic dysfunction has been recognized as nonalcoholic fatty liver disease (NAFLD). Although there is no standard therapy for NAFLD, previous reports support the effect of sodium-glucose cotransporter 2 (SGLT2) inhibitors on NAFLD. Recently, fatty liver disease with metabolic dysfunction was proposed to be defined as a novel concept, “metabolic associated fatty liver disease (MAFLD)”, and it was proposed that new criteria for MAFLD diagnosis be established. To clarify the effect of SGLT2 inhibitors on MAFLD, we analyzed the efficacy of tofogliflozin in patients with MAFLD. We conducted a single-center, retrospective study to evaluate the efficacy of tofogliflozin in patients with MAFLD treated at Kyushu University Hospital between 2017 and 2019. Tofogliflozin was used to treat 18 patients with MAFLD. To determine the efficacy of tofogliflozin, we evaluated glucose metabolism, insulin resistance, liver injury, hepatic steatosis, and body composition three and six months after drug initiation. Although our study was a preliminary study because of some limitations (e.g., retrospective, observational, single-arm study, small sample size), we show that tofogliflozin could improve liver injury in patients with MAFLD by improving glucose metabolism and insulin resistance without causing muscle loss.

Effects of SGLT2 inhibitors on cardiovascular outcomes in patients with stage 3/4 CKD: A meta-analysis

Introduction After stage 3 CKD, the risk of adverse cardiovascular events increased significantly. Therefore, we performed a meta-analysis to investigate the cardiovascular protective effect of SGLT2 inhibitors in patients with stage 3/4 CKD with different baseline kidney function or underlying diseases. Method To identify eligible trials, we systematically searched the Embase, PubMed, Web of Science, and Cochrane library databases from inception to April 15, 2021. The primary cardiovascular outcome was defined as a combination of cardiovascular mortality and hospitalization due to heart failure. Baseline kidney functions (stage 3a CKD: eGFR45-59mL/min per 1.73m2, stage 3b CKD: eGFR30-44mL/min per 1.73m2, stage 4 CKD: eGFR<30mL/min per 1.73m2) and underlying diseases (Type 2 diabetes, heart failure (Preserved ejection fraction or reduced ejection fraction), atherosclerotic cardiovascular disease) were used to stratify efficacy and safety outcomes. The results were subjected to a sensitivity analysis to ensure that they were reliable. Results In the present study, a total of eleven trials were included that involved a total of 27,823 patients with stage 3/4 CKD. The treatment and control groups contained 14,451 and 13,372 patients, respectively. In individuals with stage 3/4 CKD, SGLT2 inhibitors reduced the risk of primary cardiovascular outcomes by 26% (HR 0.74, [95% CI 0.69–0.80], I2 = 0.00%), by 30% in patients with stage 3a CKD (HR 0.70, [95% CI 0.59–0.84], I2 = 18.70%), by 23% in patients with stage 3b CKD (HR 0.77, [95% CI 0.66–0.90], I2 = 2.12%), and by 29% in patients with stage 4 CKD (HR 0.71, [95% CI 0.53–0.96], I2 = 0.00%). The risk of primary outcomes was reduced by 29% (HR 0.71, [95% CI 0.63–0.80], I2 = 0.00%) in patients with type 2 diabetes, by 28% (HR 0.72, [95% CI 0.56–0.93], I2 = 37.23%) in patients with heart failure with preserved ejection fraction, by 21% (HR 0.79, [95% CI 0.70–0.89], I2 = 0.00%) in patients with heart failure with reduced ejection fraction, and by 25% (HR 0.75, [95% CI 0.64–0.88], I2 = 0.00%) in patients with atherosclerotic cardiovascular disease. Conclusions For stage 3/4 CKD, SGLT2 inhibitors significantly decreased the risk of primary cardiovascular outcomes, and these benefits were consistent throughout the spectrum of different kidney functions, even in stage 4 CKD. There was no evidence of increased adverse outcomes across different baseline clinical complications, such as type 2 diabetes, heart failure, or atherosclerotic cardiovascular disease.

Attenuation of Adverse Postinfarction Left Ventricular Remodeling with Empagliflozin Enhances Mitochondria-Linked Cellular Energetics and Mitochondrial Biogenesis

Sodium–glucose cotransporter 2 (SGLT2) inhibitors such as empagliflozin are known to reduce the risk of hospitalizations related to heart failure irrespective of diabetic state. Meanwhile, adverse cardiac remodeling remains the leading cause of heart failure and death in the USA. Thus, understanding the mechanisms that are responsible for the beneficial effects of SGLT2 inhibitors is of the utmost relevance and importance. Our previous work illustrated a connection between adverse cardiac remodeling and the regulation of mitochondrial turnover and cellular energetics using a short-acting glucagon-like peptide-1 receptor agonist (GLP1Ra). Here, we sought to determine if the mechanism of the SGLT2 inhibitor empagliflozin (EMPA) in ameliorating adverse remodeling was similar and/or to identify what differences exist, if any. To this end, we administered permanent coronary artery ligation to induce adverse remodeling in wild-type and Parkin knockout mice and examined the progression of adverse cardiac remodeling with or without EMPA treatment over time. Like GLP1Ra, we found that EMPA affords a robust attenuation of PCAL-induced adverse remodeling. Interestingly, unlike the GLP1Ra, EMPA does not require Parkin to improve/maintain mitochondria-related cellular energetics and afford its benefits against developing adverse remodeling. These findings suggests that further investigation of EMPA is warranted as a potential path for developing therapy against adverse cardiac remodeling for patients that may have Parkin and/or mitophagy-related deficiencies.

2021 Clinical Practice Guidelines for Diabetes: Management of Cardiovascular Risk

The Committee of Clinical Practice Guidelines of the Korean Diabetes Association revised and updated the 7th Clinical Practice Guidelines in 2021. Intense multifactorial intervention including adequate control of glycemia, blood pressure, and low density lipoprotein cholesterol level and use of antiplatelet agents has been shown to reduce cardiovascular risk among patients with type 2 diabetes mellitus. In these recent guidelines, sodium-glucose cotransporter-2 inhibitors (SGLT2 inhibitors) and glucagon-like peptide 1 receptor agonists (GLP-1 RAs) with proven benefits were recommended in patients with heart failure and/or atherosclerotic cardiovascular disease (ASCVD) as mono- or combination therapy. SGLT2 inhibitors such as dapagliflozin, empagliflozin, and ertugliflozin were recommended preferentially in patients with heart failure. In those with ASCVD, treatment including SGLT2 inhibitors such as empagliflozin and dapagliflozin or GLP-1 RAs such as dulaglutide, liraglutide, and semaglutide as a combination therapy was recommended.