SGLT2 inhibitor empagliflozin monotherapy alleviates renal oxidative stress in albino Wistar diabetic rats after myocardial infarction induction

A systematic review on renal effects of SGLT2 inhibitors in rodent models of diabetic nephropathy

We have performed a systematic review of studies reporting on the renal effects of SGLT2 inhibitors in rodent models of diabetes. In 105 studies, SGLT2 inhibitors improved not only the glycemic control but also various aspects of renal function in most cases. These nephroprotective effects were similarly reported whether treatment with the SGLT2 inhibitor started concomitant with the onset of diabetes (within 1 week), early after onset (1-4 weeks) or after nephropathy had developed (>4 weeks after onset) with the latter probably having the greatest translational value. They were observed across various animal models of type 1 and type 2 diabetes/obesity (4 and 23 models, respectively), although studies in the type 2 diabetes model of db/db mice more often had negative data than in other models. Among possibly underlying pathophysiological mechanisms of nephroprotection, treatment with SGLT2 inhibitors had beneficial effects on lipid metabolism, blood pressure, glomerulosclerosis as well as renal tubular fibrosis, apoptosis, oxidative stress, and inflammation. These pathomechanisms highly influence atherosclerosis and renal health, which are two major factors that lead to an enhanced mortality in patients with diabetes and/or chronic kidney disease. Interestingly, renal SGLT2 inhibitor effects did not always correlate with those on glucose homeostasis, particularly in a limited number of direct comparative studies with other anti-diabetic treatments, indicating that nephroprotection may at least partly occur by mechanisms other than improving glycemic control. Our analyses did not provide evidence for different nephroprotective efficacy between SGLT2 inhibitors. Importantly, only four of 105 studies reported on female animals, and none provided direct comparative data between sexes. We conclude that more data on female animals and more direct comparative studies with other anti-diabetic compounds and combinations of treatments are needed.

Sodium-Glucose Transport Protein 2 Inhibitor Use for Type 2 Diabetes and the Incidence of Acute Kidney Injury in Taiwan

IMPORTANCE

The association between sodium-glucose transport protein 2 inhibitor (SGLT2i) use and the incidence of acute kidney injury (AKI) remains controversial. The benefits of SGLT2i use in patients to reduce AKI requiring dialysis (AKI-D) and concomitant diseases with AKI as well as improve AKI prognosis have not yet been established.

OBJECTIVE

To investigate the association between SGLT2i use and AKI incidence in patients with type 2 diabetes (T2D).

DESIGN, SETTING, AND PARTICIPANTS

This nationwide retrospective cohort study used the National Health Insurance Research Database in Taiwan. The study analyzed a propensity score-matched population of 104 462 patients with T2D treated with SGLT2is or dipeptidyl peptidase 4 inhibitors (DPP4is) between May 2016 and December 2018. All participants were followed up from the index date until the occurrence of outcomes of interest, death, or the end of the study, whichever was earliest. Analysis was conducted between October 15, 2021, and January 30, 2022.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of AKI and AKI-D during the study period. AKI was diagnosed using International Classification of Diseases diagnostic codes, and AKI-D was determined using the diagnostic codes and dialysis treatment during the same hospitalization. Conditional Cox proportional hazard models assessed the associations between SGLT2i use and the risks of AKI and AKI-D. The concomitant diseases with AKI and its 90-day prognosis, ie, the occurrence of advanced chronic kidney disease (CKD stage 4 and 5), end-stage kidney disease, or death, were considered when exploring the outcomes of SGLT2i use.

RESULTS

In a total of 104 462 patients, 46 065 (44.1%) were female patients, and the mean (SD) age was 58 (12) years. After a follow-up of approximately 2.50 years, 856 participants (0.8%) had AKI and 102 (<0.1%) had AKI-D. SGLT2i users had a 0.66-fold risk for AKI (95% CI, 0.57-0.75; P < .001) and 0.56-fold risk of AKI-D (95% CI, 0.37-0.84; P = .005) compared with DPP4i users. The numbers of patients with AKI with heart disease, sepsis, respiratory failure, and shock were 80 (22.73%), 83 (23.58%), 23 (6.53%), and 10 (2.84%), respectively. SGLT2i use was associated with lower risk of AKI with respiratory failure (hazard ratio [HR], 0.42; 95% CI, 0.26-0.69; P < .001) and shock (HR, 0.48; 95% CI, 0.23-0.99; P = .048) but not AKI with heart disease (HR, 0.79; 95% CI, 0.58-1.07; P = .13) and sepsis (HR, 0.77; 95% CI, 0.58-1.03; P = .08). The 90-day AKI prognosis for the risk of advanced CKD indicated a 6.53% (23 of 352 patients) lower incidence in SGLT2i users than in DPP4i users (P = .045).

CONCLUSIONS AND RELEVANCE

The study findings suggest that patients with T2D who receive SGLT2i may have lower risk of AKI and AKI-D compared with those who receive DPP4i.

SGLT2 inhibitors protect cardiomyocytes from myocardial infarction: a direct mechanism?

SGLT2 inhibitors have been developed as a novel class of glucose-lowering drugs affecting reabsorption of glucose and metabolic processes. They have been recently identified to be remarkably favorable in treating cardiovascular diseases, especially heart failure. Preclinical experiments have shown that SGLT2 inhibitors could hinder the progression of myocardial infarction and alleviate cardiac remodeling by mechanisms of metabolism influence, autophagy induction, inflammation attenuation and fibrosis reduction. Here we summarize the direct mechanism of SGLT2 inhibitors on myocardial infarction and investigate whether it could be applied to the clinic in improving cardiac function and healing after myocardial infarction.

Empagliflozin activates Wnt/β-catenin to stimulate FUNDC1-dependent mitochondrial quality surveillance against type-3 cardiorenal syndrome

Objectives

Cardiorenal syndrome type-3 (CRS-3) is an abrupt worsening of cardiac function secondary to acute kidney injury. Mitochondrial dysfunction is a key pathological mechanism of CRS-3, and empagliflozin can improve mitochondrial biology by promoting mitophagy. Here, we assessed the effects of empagliflozin on mitochondrial quality surveillance in a mouse model of CRS-3.

Methods

Cardiomyocyte-specific FUNDC1-knockout (FUNDC1^CKO) mice were subjected to CRS-3 prior to assessment of mitochondrial homeostasis in the presence or absence of empagliflozin.

Results

CRS-3 model mice exhibited lower heart function, increased inflammatory responses and exacerbated myocardial oxidative stress than sham-operated controls; however, empagliflozin attenuated these alterations. Empagliflozin stabilized the mitochondrial membrane potential, suppressed mitochondrial reactive oxygen species production, increased mitochondrial respiratory complex activity and restored the oxygen consumption rate in cardiomyocytes from CRS-3 model mice. Empagliflozin also normalized the mitochondrial morphology, mitochondrial dynamics and mitochondrial permeability transition pore opening rate in cardiomyocytes. Cardiomyocyte-specific ablation of FUN14 domain-containing protein 1 (FUNDC1) in mice abolished the protective effects of empagliflozin on mitochondrial homeostasis and myocardial performance. Empagliflozin activated β-catenin and promoted its nuclear retention, thus increasing FUNDC1-induced mitophagy in heart tissues; however, a β-catenin inhibitor reversed these effects.

Conclusions

In summary, empagliflozin activated Wnt/β-catenin to stimulate FUNDC1-dependent mitochondrial quality surveillance, ultimately improving mitochondrial function and cardiac performance during CRS-3. Thus, empagliflozin could be considered for the clinical management of heart function following acute kidney injury.

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Empagliflozin reduces myocardial damage and improves myocardial function after CRS-3.

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Empagliflozin normalizes the mitochondrial structure in cardiomyocytes during CRS-3.

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Empagliflozin attenuates cardiomyocyte mitochondrial dysfunction during CRS-3.

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Empagliflozin activates FUNDC1-dependent mitophagy and preserves mitochondrial integrity in the heart during CRS-3.

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Loss of FUNDC1 abolishes the cardioprotective effects of empagliflozin during CRS-3.

Diabetes modulation of the myocardial infarction- acute kidney injury axis

Since there is crosstalk in functions of the heart and kidney, acute or chronic injury in one of the two organs provokes adaptive and/or maladaptive responses in both organs, leading to cardiorenal syndrome (CRS). Acute kidney injury (AKI) induced by acute heart failure is referred to as type 1 CRS, and a frequent cause of this type of CRS is acute myocardial infarction (AMI). Diabetes mellitus increases the risk of AMI and also the risk of AKI of various causes. However, there have been only a few studies in which animal models of diabetes were used to examine how diabetes modulates AMI-induced AKI. In this review, we summarize findings regarding the mechanisms of type 1 CRS and the impact of diabetes on both AMI and renal susceptibility to AKI and we discuss mechanisms by which diabetes modulates AMI-induced AKI. Hemodynamic alterations induced by AMI could be augmented by diabetes via its detrimental effect on infarct size and contractile function of the non-infarcted region in the heart. Diabetes increases susceptibility of renal cells to hypoxia and oxidative stress by modulation of signaling pathways that regulate cell survival and autophagy. Recent studies have shown that diabetes mellitus even at early stage of cardiomyopathy/nephropathy predisposes the kidney to AMI-induced AKI, in which activation of toll-like receptors and reactive oxygen species derived from NADPH oxidases are involved. Further analysis of crosstalk between diabetic cardiomyopathy and diabetic kidney disease is necessary for obtaining a more comprehensive understanding of modulation of the AMI-AKI axis by diabetes.

Inflammation and Oxidative Stress in Diabetic Kidney Disease: The Targets for SGLT2 Inhibitors and GLP-1 Receptor Agonists

The incidence of type 2 diabetes (T2D) has been increasing worldwide, and diabetic kidney disease (DKD) remains one of the leading long-term complications of T2D. Several lines of evidence indicate that glucose-lowering agents prevent the onset and progression of DKD in its early stages but are of limited efficacy in later stages of DKD. However, sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor (GLP-1R) agonists were shown to exert nephroprotective effects in patients with established DKD, i.e., those who had a reduced glomerular filtration rate. These effects cannot be solely attributed to the improved metabolic control of diabetes. In our review, we attempted to discuss the interactions of both groups of agents with inflammation and oxidative stress—the key pathways contributing to organ damage in the course of diabetes. SGLT2i and GLP-1R agonists attenuate inflammation and oxidative stress in experimental in vitro and in vivo models of DKD in several ways. In addition, we have described experiments showing the same protective mechanisms as found in DKD in non-diabetic kidney injury models as well as in some tissues and organs other than the kidney. The interaction between both drug groups, inflammation and oxidative stress appears to have a universal mechanism of organ protection in diabetes and other diseases.