Mechanistic effects of SGLT2 inhibition on blood pressure in diabetes

Sodium-glucose cotransporter 2 inhibitors and renin-angiotensin-aldosterone system, possible cellular interactions and benefits

Sodium glucose cotransporter 2 inhibitors (SGLT2is) are a newly developed class of anti-diabetics which exert potent hypoglycemic effects in the diabetic milieu. However, the evidence suggests that they also have extra-glycemic effects. The renin-angiotensin-aldosterone system (RAAS) is a hormonal system widely distributed in the body that is important for water and electrolyte homeostasis as well as renal and cardiovascular function. Therefore, modulating RAAS activity is a main goal in patients, notably diabetic patients, which are at higher risk of complications involving these organ systems. Some studies have suggested that SGLT2is have modulatory effects on RAAS activity in addition to their hypoglycemic effects and, thus, these drugs can be considered as promising therapeutic agents for renal and cardiovascular disorders. However, the exact molecular interactions between SGLT2 inhibition and RAAS activity are not clearly understood. Therefore, in the current study we surveyed the literature for possible molecular mechanisms by which SGLT2is modulate RAAS activity.

Empagliflozin alleviates diabetes-induced cognitive impairments by lowering nicotinamide adenine dinucleotide phosphate oxidase-4 expression and potentiating the antioxidant defense system in brain tissue of diabetic rats

BACKGROUND

Diabetes-induced cognitive impairment is a major challenge in patients with uncontrolled diabetes mellitus. It has a complicated pathophysiology, but the role of oxidative stress is central. Therefore, the use of antidiabetic drugs with extra-glycemic effects that reduce oxidative damage may be a promising treatment option.

METHODS

Male Wistar rats were randomly divided into four groups as normal, normal treated, diabetic and diabetic treated (n = 8 per group). Type 1 diabetes was induced by a single intraperitoneal dose of streptozotocin (STZ) (40 mg/kg). Two treatment groups received empagliflozin for 5 weeks (20 mg/kg/po). Cognitive ability was evaluated using open field, Elevated Plus Maze (EPM) and the Morris Water Maze (MWM) tests at study completion. Blood and brain tissue samples were collected - and analysis for malondialdehyde (MDA) and glutathione (GLT) content and catalase (CAT) and superoxide dismutase (SOD) enzyme activity were performed. Additionally, expression of nicotinamide adenine dinucleotide phosphate oxidase-4 (Nox-4) enzyme in brain tissue was analyzed using RT-PCR.

RESULTS

STZ increased blood glucose and induced diabetes with oxidative stress by lowering the antioxidant system potency and increasing Nox-4 expression after 5-weeks in brain tissue accompanied by reduction in cognitive performance. Also, diabetes induced anxiety-like behavior and impaired spatial memory in MWM, EPM and open field tests. However, empagliflozin reversed these changes, improving SOD and CAT activity, GLT content and reducing Nox-4 expression and MDA concentration in brain tissue while improving cognitive ability. It reduced anxiety and depression-related activities. It also improved spatial memory in MWM test.

CONCLUSION

Uncontrolled diabetes negatively impacts mental function and impairs learning and cognitive performance via oxidative stress induction, the Nox-4 enzyme playing a central role. Empagliflozin reverses these effects, improving cognitive ability via promoting the anti-oxidative system and damping Nox-4 free radical generator enzyme expression. Therefore, empagliflozin is a promising treatment, providing both antidiabetic and extra-glycemic benefits for improving brain function in the diabetic milieu.

Cognitive Benefits of Sodium-Glucose Co-Transporters-2 Inhibitors in the Diabetic Milieu

Patients with diabetes are at higher risk of cognitive impairment and memory loss than the normal population. Thus, using hypoglycemic agents to improve brain function is important for diabetic patients. Sodium-glucose cotransporters-2 inhibitors (SGLT2i) are a class of therapeutic agents used in the management of diabetes that has some pharmacologic effects enabling them to fight against the onset and progress of memory deficits. Although the exact mediating pathways are not well understood, emerging evidence suggests that SGLT2 inhibition is associated with improved brain function. This study reviewed the possible mechanisms and provided evidence suggesting SGLT2 inhibitors could ameliorate cognitive deficits.

Nanoparticles with SGLT2 inhibitory activity: Possible benefits and future

AIM

Nano-drug delivery is a rapidly growing approach in medicine that helps design and develop newer forms of drugs with more efficacy and lower adverse effects. Sodium-glucose cotransporter-2 inhibitors are an emerging class of antidiabetic agents that reduce the blood glucose levels by damping glucose reabsorption in renal proximal tubules.

METHODS AND RESULTS

This mechanism might be followed by some adverse effects that could be prevented by nano-drug delivery. Although we have still limited evidence about nanoforms of sodium-glucose cotransporter-2 inhibitors, current knowledge strongly suggests that nanotechnology can help us design more effective drugs with lower side effects. In recent years, several studies have explored the possible benefits of nanoforms of sodium-glucose cotransporter-2 inhibitors. However, clinical trials are yet to be conducted.

CONCLUSION

In the current review, we present the latest findings on the development and benefits of nanoforms of sodium-glucose cotransporter-2 inhibitors.

Sodium-glucose co-transporter-2 inhibitors and epicardial adiposity

Epicardial adipose tissue is a layer of adipocytes that physiologically surround the myocardium and play some physiologic roles in normal heart function. However, in pathologic conditions, the epicardial adipose tissue can present a potent cardiac risk factor that is capable of impairing heart function through several pathways, increasing the risk of dysrhythmia and creating an inflammatory milieu around the heart tissues. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) are a relatively newly introduced class of antidiabetes drugs which effectively normalize blood glucose via overt glycosuria. Some recent reports suggest that these drugs are able to modulate epicardial adiposity and decrease the risk of cardiac complications in diabetic patients who are at higher risk of epicardial adiposity-dependent cardiac disorders. If proven to be true, these antidiabetic drugs can provide dual benefits as both hypoglycemic agents and as epicardial adiposity normalizing agents, thus providing cardiac benefits. In this study, we discuss the physiological and pathophysiological importance of epicardial adiposity and the potential positive effects of SGLT2is in the diabetic milieu.

Mechanistic View on the Effects of SGLT2 Inhibitors on Lipid Metabolism in Diabetic Milieu

Chronic hyperglycemia induces pathophysiologic pathways with negative effects on the metabolism of most substrates as well as lipids and lipoproteins, and thereby induces dyslipidemia. Thus, the diabetic milieu is commonly accompanied by different levels of atherogenic dyslipidemia, which is per se a major risk factor for subsequent complications such as atherosclerosis, coronary heart disease, acute myocardial infarction, ischemic stroke, and nephropathy. Therefore, readjusting lipid metabolism in the diabetic milieu is a major goal for preventing dyslipidemia-induced complications. Sodium-glucose cotransporter-2 (SGLT2) inhibitors are a class of relatively newly introduced antidiabetes drugs (including empagliflozin, canagliflozin, dapagliflozin, etc.) with potent hypoglycemic effects and can reduce blood glucose by inducing glycosuria. However, recent evidence suggests that they could also provide extra-glycemic benefits in lipid metabolism. It seems that they can increase fat burning and lipolysis, normalizing the lipid metabolism and preventing or improving dyslipidemia. Nevertheless, the exact mechanisms involved in this process are not well-understood. In this review, we tried to explain how these drugs could regulate lipid homeostasis and we presented the possible involved cellular pathways supported by clinical evidence.

Impacts of Sodium/Glucose Cotransporter-2 Inhibitors on Circulating Uric Acid Concentrations: A Systematic Review and Meta-Analysis

BACKGROUND

Several trials have assessed the antihyperglycemic effects of sodium/glucose cotransporter-2 inhibitors (SGLT2i) in patients with type 2 diabetes mellitus (T2DM). We conducted a quantitative analysis to assess the impact of SGLT2is on serum uric acid (SUA) in patients with T2DM.

METHODS

Placebo-controlled trials published before 13 August 2021 were identified by searching PubMed, Embase, Web of Science, and Scopus. The intervention group received SGLT2i as monotherapy or add-on treatment, and the control group received a placebo that was replaced with SGLT2i. Clinical trials providing changes in SUA were included. The mean change of SUA, glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and body weight were calculated (PROSPERO CRD42021287019).

RESULTS

After screening of 1172 papers, 59 papers were included in the systematic review. A total of 55 trials (122 groups) of 7 types of SGLT2i on patients with T2DM were eligible for meta-analysis. All SGLT2is significantly decreased SUA levels compared with the placebo groups: empagliflozin mean difference (MD) = -40.98 μmol/L, 95% CI [-47.63, -34.32], dapagliflozin MD = -35.17 μmol/L, 95% CI [-39.68, -30.66], canagliflozin MD = -36.27 μmol/L, 95% CI [-41.62, -30.93], luseogliflozin MD = -24.269 μmol/L, 95% CI [-33.31, -15.22], tofogliflozin MD = -19.47 μmol/L, 95% CI [-27.40, -11.55], and ipragliflozin MD = -18.85 μmol/L, 95% CI [-27.20, -10.49]. SGLT2i also decreased FPG, body weight, and HbA1c levels. SUA reduction persisted during long-term treatment with SGLT2i (except for empagliflozin), while the SUA reduction was affected by the duration of diabetes.

CONCLUSIONS

SGLT2i can be a valid therapeutic strategy for patients with T2DM and comorbid hyperuricemia. Besides reducing FPG, body weight, and HbA1c, SGLT2i can significantly decrease SUA levels compared to placebo (Total MD = -34.07 μmol/L, 95% CI [-37.00, -31.14]).

[SGLT2 inhibitors: A new era for our patients]

Since 2015, 10 randomized clinical trials assessed the cardiovascular safety of SGLT2 inhibitors, and then assessed the potential renal and cardiovascular benefits of these drugs (EMPAREG Outcome, CANVAS, DECLARE, DAPA-HF, CREDENCE, EMPEROR-reduced, VERTIS, DAPA-CKD, SCORED, SOLOIST-WHF) in over 88,000 patients. The results of EMPAREG Outcome showed major renal and cardiovascular protection but they were unexpected. The other trials regarding the effects of dapagliflozin, canagliflozin, empagliflozin and more recently sotagliflozin have confirmed most of these results and extended them to other populations. There is no scientific doubt that these drugs confer a marked renal protection in patients already treated with renin angiotensin system blockers (reduction of the risk of end-stage renal disease: -35 to 40%) et reduce the risk of hospitalization for heart failure (-30 to 35%), especially in patients with heart failure with reduced ejection fraction. The benefit/risk profile is highly favorable but minor (genital candidosis, urinary tract infections, euglycemic acido-ketosis) and serious (Fournier gangrene) side effects must not be forgotten. Renal protection is twice the effect of renin angiotensin system blockers, and is maintained in patients already treated with them, in patients with GFR 25mL/min/1.73m² and over, regardless of whether they have type 2 diabetes mellitus or not (of note, patients with type 1 diabetes mellitus, polycystic kidney disease, lupus and vasculitis were excluded in these studies). Reduction of the incidence of heart failure is similar to that observed with sacubitril/valsartan, and is maintained in patients already treated with sacubitril/valsartan. SGLT2 inhibitors have now defined a new standard of care, and it will be necessary to explore the proper use of the new mineralocorticoid receptor antagonist finerenone that demonstrated significant renal and cardiovascular protection in mostly SGLT2 inhibitors-untreated diabetic patients with chronic kidney disease (or even some GLP-1 agonists). A new era for our patients.

Efficacy and Safety of SGLT-2 Inhibitors for Treatment of Diabetes Mellitus among Kidney Transplant Patients: A Systematic Review and Meta-Analysis

BACKGROUND

The objective of this systematic review was to evaluate the efficacy and safety profiles of sodium-glucose co-transporter 2 (SGLT-2) inhibitors for treatment of diabetes mellitus (DM) among kidney transplant patients.

METHODS

We conducted electronic searches in Medline, Embase, Scopus, and Cochrane databases from inception through April 2020 to identify studies that investigated the efficacy and safety of SGLT-2 inhibitors in kidney transplant patients with DM. Study results were pooled and analyzed utilizing random-effects model.

RESULTS

Eight studies with 132 patients (baseline estimated glomerular filtration rate (eGFR) of 64.5 ± 19.9 mL/min/1.73m2) treated with SGLT-2 inhibitors were included in our meta-analysis. SGLT-2 inhibitors demonstrated significantly lower hemoglobin A1c (HbA1c) (WMD = -0.56% [95%CI: -0.97, -0.16]; p = 0.007) and body weight (WMD = -2.16 kg [95%CI: -3.08, -1.24]; p < 0.001) at end of study compared to baseline level. There were no significant changes in eGFR, serum creatinine, urine protein creatinine ratio, and blood pressure. By subgroup analysis, empagliflozin demonstrated a significant reduction in body mass index (BMI) and body weight. Canagliflozin revealed a significant decrease in HbA1C and systolic blood pressure. In terms of safety profiles, fourteen patients had urinary tract infection. Only one had genital mycosis, one had acute kidney injury, and one had cellulitis. There were no reported cases of euglycemic ketoacidosis or acute rejection during the treatment.

CONCLUSION

Among kidney transplant patients with excellent kidney function, SGLT-2 inhibitors for treatment of DM are effective in lowering HbA1C, reducing body weight, and preserving kidney function without reporting of serious adverse events, including euglycemic ketoacidosis and acute rejection.

Clinical Efficacy of Quadruple Oral Therapy for Type 2 Diabetes in Real-World Practice: A Retrospective Observational Study

INTRODUCTION

We aimed to evaluate the effectiveness of quadruple oral therapy in patients with inadequately controlled type 2 diabetes (T2D) with the use of three types of oral hypoglycemic agents.

METHODS

Medical records of 318 patients with T2D who were prescribed quadruple therapy in the Asan Medical Center were reviewed. Changes in glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG) levels from baseline were assessed. The regimens of quadruple oral therapy included the following: (1) thiazolidinedione (TZD) add-on to metformin (MET) + sulfonylurea (SU) + dipeptidyl peptidase 4 inhibitor (DPP4i), (2) sodium-glucose cotransporter 2 inhibitor (SGLT2i) add-on to MET + SU + DPP4i, and (3) DPP4i add-on to MET + SU + TZD.

RESULTS

The TZD add-on significantly reduced HbA1c levels by 1.1% (from 9.0 ± 1.1 to 7.9 ± 1.1%, P < 0.001) and FPG levels by 41.4 mg/dL (from 188.9 ± 45.9 to 147.4 ± 51.3 mg/dL, P < 0.001). The SGLT2i add-on changed the mean HbA1c level from 8.9 ± 1.0 to 7.8 ± 1.0%, a reduction of 1.1% (P < 0.001) and changed the mean FPG level from 193.4 ± 46.2 to 152.6 ± 37.0 mg/dL, a reduction of 40.8 mg/dL (P < 0.001). Finally, the DPP4i add-on reduced HbA1c levels by 1.3% (from 9.1 ± 1.3 to 7.8 ± 1.4%, P < 0.001) and FPG levels by 39.3 mg/dL (from 190.7 ± 45.3 to 151.4 ± 41.6 mg/dL, P < 0.001). Patients with higher baseline HbA1c levels (≥ 9.0%) showed a better response to quadruple therapy than those with baseline HbA1c levels lower than 9.0% for all three regimens.

CONCLUSION

Quadruple oral hypoglycemic therapy can be a feasible option in patients with T2D.

Neuromodulatory effects of anti-diabetes medications: A mechanistic review

Diabetes mellitus is a potent upstream event in the molecular pathophysiology which gives rise to various diabetes-related complications. There are several classes of anti-diabetic medications that have been developed to normalize blood glucose concentrations through a variety of molecular mechanisms. Beyond glucose-lowering effects, these agents may also provide further therapeutic potential. For instance, there is a high incidence of diabetes-induced neuronal disorders among patients with diabetes, who may also develop neurodegenerative and psychological complications. If anti-diabetic agents can modify the molecular mechanisms involved in the pathophysiology of neuronal comorbidities, this could potentially be translated to reducing the risk of other neurological conditions such as Alzheimer's disease, Parkinson's disease, depression, memory deficits and cognition impairments among patients with diabetes. This review aimed to shed light on some of the potentially beneficial aspects of anti-diabetic agents in lowering the risk or treating neuronal disorders by reviewing the molecular mechanisms by which these agents can potentially modulate neuronal behaviors.

Effects of newly introduced antidiabetic drugs on autophagy

Diabetes mellitus is a chronic metabolic disorder that has a complex molecular and cellular pathophysiology, resulting in its dynamic progression and that may show differing responses to therapy. The incidence of diabetes mellitus increases with age and requires additive therapeutic agents for its management. SGLT2i and DPP-4 inhibitors and GLP-1 receptor agonists (GLP-1RA) are newly introduced antidiabetic drugs that work through differing mechanisms; DPP-4 inhibitors maintain the endogenous level of GLP1; GLP-1RA result in pharmacological levels of GLP1, whilst SGLT2i act on the proximal tubules of the kidney. They have shown efficacy in the management of diabetes and in contrast to other antidiabetic drugs, do not inherently cause hypoglycemia in therapeutic doses. Autophagy as a highly conserved mechanism to maintain cell survival and homeostasis by degradation of damaged or aged organelles and components, and recognised to be increasingly important in diabetes. In the present review, we discuss the modulatory effects of these newly introduced antidiabetic drugs on the autophagy process.