Hepatic expression of sodium-glucose cotransporter 2 (SGLT2) in patients with chronic liver disease

Update in non-alcoholic fatty liver disease management: role of sodium-glucose cotransporter 2 inhibitors

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in hepatocytes without significant alcohol consumption. It is closely associated with sedentarism, hypercaloric diets, obesity, dyslipidemia, insulin resistance, type 2 diabetes mellitus, and genetic predisposition. NAFLD comprises a spectrum of liver disorders, from simple steatosis to non-alcoholic (NASH) and liver cirrhosis. The complex etiological mechanisms include oxidative stress, inflammation, apoptosis, and fibrosis; therefore, its management is challenging. Sodium-glucose cotransporter type 2 inhibitors (SGLT2i), a class of antidiabetic drugs, have emerged as promising therapeutic agents due to their ability to improve key metabolic parameters, including obesity, dyslipidemia, insulin resistance, and hyperglycemia. This review explores the cellular mechanisms by which SGLT2i, either as monotherapy or combined with other treatments, modulate signaling pathways involved in lipid and carbohydrate metabolism. Additionally, we examine their effects on oxidative stress, inflammation, fibrosis, and apoptosis, which are critical drivers of NAFLD progression. This review is intended to summarize the multiple benefits of SGLT2 inhibitors and to educate healthcare providers on the therapeutic potential of these drugs in order to foster their incorporation into effective NAFLD management plans.

The Role of Diabetes and SGLT2 Inhibitors in Cerebrovascular Diseases

PURPOSE OF REVIEW

Diabetes is a well-established risk factor for stroke. Understanding the pathophysiology of this connection is crucial to implementing appropriate prevention strategies. Lately, there has been a paradigm shift in the care of individuals with diabetes toward the use of glucose-lowering medications with potential cardiovascular, cerebrovascular or cardiorenal benefits. The aim of this article is to provide a critical analysis of the role of diabetes in cerebrovascular disease and current evidence and recommendations for the use of glucose-lowering medication with particular focus on the sodium glucose cotransporter-2 inhibitor (SGLT2i) class.

RECENT FINDINGS

Intensive glycemic control in individuals with diabetes reduces the risk of microvascular complications, but there is less clear evidence for decreasing risk of macrovascular events (e.g., stroke). A multifaceted management of diabetes addressing healthy lifestyle practices, glycemic control, and optimization of other cardiovascular risk factors is highly recommended. SGLT2i are the latest class of antihyperglycemic agents available for diabetes management. Canagliflozin and empagliflozin are associated with reduction in major adverse cardiovascular events (MACE). Dapagliflozin did not reduce the rate of MACE but is associated with reduction in heart-failure related death and hospitalization and has the potential to decrease dementia risk. Ertugliflozin decreases rates of hospitalization related to heart failure however it was non-inferior to placebo in reducing MACE. There is increasing evidence that the use of SGLT2i may reduce the risk of stroke, particularly hemorrhagic stroke, in individuals with type 2 diabetes and a high risk of cardiovascular events, and that SGLT2i may also be beneficial for brain health by decreasing risk of cognitive decline and dementia. Antihyperglycemic therapy should be tailored to patients' circumstances. SGLT2i treatment should be considered in patients with type 2 diabetes and established or high-risk cardiovascular disease, heart failure, or chronic kidney disease, to reduce the overall cerebro-cardiovascular and renal risks.

Glucagon-Like Peptide 1 Receptor Agonists and Sodium-Glucose Cotransporter 2 Inhibitors and the Prevention of Cirrhosis Among Patients With Type 2 Diabetes

OBJECTIVE

To determine whether glucagon-like peptide 1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 (SGLT-2) inhibitors, separately, compared with dipeptidyl peptidase 4 (DPP-4) inhibitors are associated with a reduced risk of cirrhosis and other adverse liver outcomes among patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

With an active comparator, new-user approach, we conducted a cohort study using the U.K. Clinical Practice Research Datalink linked with hospital and national statistics databases. Cox proportional hazards models using propensity score fine stratification weighting were used to calculate hazard ratios (HRs) and 95% CIs for cirrhosis (primary outcome) and decompensated cirrhosis, hepatocellular carcinoma, and liver-related mortality (secondary outcomes).

RESULTS

In the first cohort comparing 25,516 patients starting GLP-1RAs and 186,752 starting DPP-4 inhibitors, GLP-1RAs were not associated with the incidence of cirrhosis (HR 0.90, 95% CI 0.68-1.19) or the secondary outcomes. In a separate cohort comparing 33,161 patients starting SGLT-2 inhibitors and 124,431 starting DPP-4 inhibitors, SGLT-2 inhibitors were associated with a reduced incidence of cirrhosis (HR 0.64, 95% CI 0.46-0.90), as also decompensated cirrhosis (HR 0.74, 95% CI 0.54-1.00), but not with a lower risk of hepatocellular carcinoma or liver-related mortality.

CONCLUSIONS

In patients with type 2 diabetes in the U.K., GLP-1RAs were not associated with a lower risk of cirrhosis compared with DPP-4 inhibitors in patients with type 2 diabetes. However, SGLT-2 inhibitors were associated with a lower risk of cirrhosis compared with DPP-4 inhibitors.

Cardiac Fibrosis: Mechanistic Discoveries Linked to SGLT2 Inhibitors

Sodium-glucose cotransporter 2 inhibitors (SGLT2is), commonly known as flozins, have garnered attention not only for their glucose-lowering effects in type 2 diabetes mellitus (T2DM) but also for their cardioprotective properties. This review examines the mechanisms underlying the anti-fibrotic effects of SGLT2is, with a focus on key clinical trials and preclinical models. SGLT2is, mainly empagliflozin and dapagliflozin, have demonstrated significant reductions in heart failure-related hospitalizations, cardiovascular death, and fibrosis markers, independent of their glucose-lowering effects. The cardioprotective benefits appear to stem from direct actions on cardiac tissues, modulation of inflammatory responses, and improvements in metabolic parameters. In animal models of heart failure, SGLT2is were demonstrated to reduce cardiac fibrosis through mechanisms involving AMPK activation, reduced oxidative stress, and inhibition of pro-fibrotic pathways, not only through the inhibition of SGLT2 present on cardiac cells but also by targeting several other molecular targets. These findings confirm their efficacy in the treatment of heart failure and align with evidence from human trials, supporting the potential involvement of multiple pathways in mediating cardiac fibrosis. These results also provide a promising basis for clinical trials specifically targeting pathways shared with SGLT2is.

SGLT2 Inhibitors: The First Endothelial-Protector for Diabetic Nephropathy

Sodium-glucose co-transporter type 2 inhibitors (SGLT2i) have emerged as a class of agents relevant for managing diabetic nephropathy and cardiopathy. In a previous report, we noticed that these drugs share, with other drugs with "nephroprotective" effects, the ability to reduce the glomerular filtration rate (GFR), thus suggesting the kidney hemodynamic effect as a proxy for optimal drug dosage. We also noticed that all known nephroprotective drugs exert cardioprotective functions, suggesting the possibility of activities not mediated by the kidney. Finally, we observe that nephroprotective drugs can be grouped according to their effects on hemoglobin levels, thus suggesting their mechanism of action. While the primary mechanism of SGLT2i involves glycosuria and natriuria, growing evidence suggests broader therapeutic effects beyond hemodynamic modulation. Specifically, the evidence that SGLT2 can be expressed in several atypical regions under pathological conditions, supports the possibility that its inhibition has several extratubular effects. Evidence supports the hypothesis that SGLT2i influence mitochondrial function in various cell types affected by diabetes, particularly in the context of diabetic nephropathy. Notably, in SGLT2i-treated patients, the extent of albumin-creatinine ratio (ACR) reduction post-treatment may be correlated with mitochondrial staining intensity in glomerular endothelial cells. This implies that the anti-proteinuric effects of SGLT2i could involve direct actions on glomerular endothelial cell. Our investigation into the role of SGLT2 inhibitors (SGLT2i) in endothelial function suggests that the aberrant expression of SGLT2 in endothelial cells in T2DM would lead to intracellular accumulation of glucose; therefore, SGLT2i are the first type of endothelial protective drugs available today, with potential implications for ageing-related kidney disease. The review reveals two major novel findings: SGLT2 inhibitors are the first known class of endothelial-protective drugs, due to their ability to prevent glucose accumulation in endothelial cells where SGLT2 is aberrantly expressed in Type 2 Diabetes. Additionally, the research demonstrates that SGLT2 inhibitors share a GFR-reducing effect with other nephroprotective drugs, suggesting both a mechanism for optimal drug dosing and potential broader applications in ageing-related kidney disease through their effects on mitochondrial function and glomerular endothelial cells.

Comparison of baseline clinical characteristics among people with type 2 diabetes on second-line therapy previously added with dapagliflozin or another oral glucose-lowering drug: AGORA study

INTRODUCTION

Type 2 diabetes mellitus (T2D) has acquired epidemic proportions worldwide. In recent years, new oral glucose-lowering drugs (OGLD) have emerged that improve the cardiovascular-kidney-metabolic control in T2D people.

OBJECTIVES

To compare the baseline clinical-biological characteristics among T2D people to whom had added-on dapagliflozin (DAPA group) or another OGLD (SOC group) second-line hypoglycaemic therapies among the AGORA study population.

METHODS

This is a multicentre cross-sectional observational study of the baseline characteristics of T2D people recruited through competitive sampling among 46 primary care health centres in Spain for the AGORA study. The inclusion and exclusion criteria of participants, and justification of the sample size are reported. After verifying the data necessary to be evaluated and informed consent, 317 subjects were included to the DAPA group and 288 to the SOC group. Both categorical and continuous variables were analysed and compared with the usual statistics. Cohen's d was used to assess the standardised difference in means.

RESULTS

Six hundred and five patients with T2D were assessed (mean age 63.5 [SD±8.1] years, 61.8% men), whom 17.4% were smokers, 47.6% had obesity, 74.8% hypertension, 87.3% dyslipidaemia, and 41.7% reported physical inactivity, with no significant differences between both comparison groups. The mean (SD) evolution time of T2D was 10.1 (5.6) years. Most baseline clinical-biological characteristics at recruitment were similar in both groups. However, DAPA group was younger (2.9 years), and had lower systolic blood pressure (SBP) (2.8mmHg), higher body weight (BW) (3.7kg), and higher glycated haemoglobin A1c (HbA1c) (0.3%) than SOC group. Only 11.5% of participants had poor glycaemic control (HbA1c>8%) at recruitment, 54.9% had good glycaemic control (HbA1c<7%), being significantly lower in the DAPA group (47.3%) than in the SOC group (63.4%). The percentage of T2D patients with high vascular risk (VR) was 46.3%, and 53.7% with very high VR, being significantly higher in the DAPA group (57.4%) than in the SOC group (49.6%).

CONCLUSIONS

Most baseline cardiovascular-kidney-metabolic characteristics were similar in T2D patients whom had added dapagliflozin on second-line hypoglycaemic therapy as those whom had added-on another OGLD. However, patients whom had added-on dapagliflozin had higher VR, lower SBP, higher BW, and slightly worse HbA1c control. Future research is necessary to explain the causes of these differences in cardiometabolic control.

Effects of SGLT2 inhibitors on the onset of esophageal varices and extrahepatic cancer in type 2 diabetic patients with suspected MASLD: a nationwide database study in Japan

BACKGROUND & AIM

SGLT2 inhibitors (SGLT2i) improve hepatic steatosis in patients with type 2 diabetes mellitus (T2DM) and MASLD. We aimed to investigate the impact of SGLT2i on the incidence of liver-related events and extrahepatic cancer compared to DPP4 inhibitors (DPP4i) in patients with T2DM and suspected MASLD using a medical claims database in Japan.

METHODS

We conducted a retrospective study using a Japanese medical claims database. Among patients with T2DM who were prescribed SGLT2i or DPP4i (n = 1,628,656), patients with suspected MASLD were classified into SGLT2i (n = 4204) and DPP4i (n = 4204) groups. Effects of SGLT2i on the following outcomes were compared to DPP4i: (1) changes in HbA1c and ALT levels after 6 months, (2) changes in hepatic fibrosis index, and (3) the incidence of liver-related events/extrahepatic cancer over 12 months.

RESULTS

After 6 months, DPP4i significantly decreased HbA1c levels compared to SGLT2i. In contrast, SGLT2i significantly decreased ALT levels compared to DPP4i. SGLT2i significantly decreased FIB-4 index compared to DPP4i over 12 months. Although no significant difference was observed in the incidence of overall liver-related events between the two groups, SGLT2i significantly reduced the incidence of esophageal varices (HR 0.12, 95%CI 0.01-0.95, P = 0.044). Moreover, SGLT2i significantly suppressed the incidence of extrahepatic cancer (HR 0.50, 95%CI 0.30-0.84, P = 0.009) compared to DPP4i.

CONCLUSION

SGLT2i was more beneficial than DPP4i in improving the hepatic inflammation and fibrosis indices. Moreover, SGLT2i suppressed the incidence of esophageal varices and extrahepatic cancer compared to DPP4i. SGLT2i may suppress life-threatening events in patients with T2DM and suspected MASLD.

Sodium-glucose cotransporter 2 inhibitors ameliorate ER stress-induced pro-inflammatory cytokine expression by inhibiting CD36 in NAFLD progression in vitro

Sodium-dependent glucose cotransporter-2 (SGLT2) inhibitors, antidiabetic drugs that reduce blood sugar levels by inhibiting glucose reabsorption in the renal proximal tubules, also ameliorate nonalcoholic fatty liver disease (NAFLD). This study aimed to examine the effects of SGLT2 inhibition on hepatic steatosis and nonalcoholic steatohepatitis (NASH) using an in vitro model of NAFLD progression. HepG2 cells and a coculture of Hepa1c1c7 and Raw 264.7 cells were treated with 400 μM palmitic acid (PA), followed by treatment with or without 10 μM empagliflozin and dapagliflozin. In HepG2 cells, PA increased hepatic lipid accumulation, the expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), exocytosis mediators (VAMP3 and SNAP23), and ER stress markers (GRP78, PERK, IRE1α, ATF6, ATF4, and CHOP), and the gene and protein expression of CD36. SGLT2 inhibitors reversed the effects of PA. SGLT2 inhibition via siRNA reduced proinflammatory-cytokine gene expression in thapsigargin-treated HepG2 cells. Transfection with CD36 siRNA reversed the elevated ATF4 and CHOP expression in PA-treated HepG2 cells. SGLT2 inhibition via an SGTL2 inhibitor and SGLT2 siRNA reduced CD36, Tnf-α, Il-6, Il-1β, Vamp2, Snap23, Atf4, and Chop expression in the PA-treated Hepa1c1c7-Raw 264.7 cell coculture and suppressed Tnf-α release in the Hepa1c1c7-Raw 264.7 cell coculture treated with lipopolysaccharide and PA. These findings indicate that SGLT2 inhibitors inhibited NAFLD progression by reducing hepatic lipid accumulation and inflammation.

Effects of luseogliflozin on suspected MASLD in patients with diabetes: a pooled meta-analysis of phase III clinical trials

BACKGROUND

Luseogliflozin, a sodium-glucose cotransporter 2 inhibitor, potentially exerts pleiotropic effects on the liver. However, the sufficient evidence is still lacking. We aimed to investigate the effects of luseogliflozin on hepatic steatosis, fibrosis, and cardiometabolic risk factors in diabetic patients by a pooled meta-analysis.

METHODS

In this pooled meta-analysis, we enrolled diabetic patients who participated in phase III clinical trials of luseogliflozin (luseogliflozin group n = 302, placebo group n = 191). The primary outcomes were changes in fatty liver index (FLI) and Hepamet fibrosis score (HFS) after 24 weeks. The secondary outcomes were changes in cardiometabolic risk factors after 24 weeks. Statistical analysis was performed using propensity scoring analysis by the inverse probability of treatment weighting method.

RESULTS

Primary outcomes: Luseogliflozin significantly decreased FLI compared to placebo after 24 weeks (adjusted coefficient - 5.423, 95%CI - 8.760 to - 2.086, P = 0.0016). There was no significant difference in changes in HFS between the two groups. However, luseogliflozin significantly decreased HFS compared to placebo in diabetic patients with ALT > 30 U/L (adjusted coefficient - 0.039, 95%CI - 0.077 to - 0.001, P = 0.0438) and with FIB-4 index > 1.3 (adjusted coefficient - 0.0453, 95%CI - 0.075 to - 0.016, P = 0.0026). Secondary outcom8es: Luseogliflozin significantly decreased HbA1c level, HOMA-IR value, BMI, and uric acids level, and increased HDL cholesterol level compared to placebo.

CONCLUSIONS

This pooled meta-analysis demonstrated that 24-week treatment with luseogliflozin improved hepatic steatosis and fibrosis indexes in diabetic patients, especially those with liver injury. Furthermore, luseogliflozin improved various cardiometabolic risk factors. Thus, luseogliflozin may be useful for improving MASLD in diabetic patients.

Doxorubicin‑induced cardiomyopathy is mitigated by empagliflozin via the modulation of endoplasmic reticulum stress pathways

Doxorubicin (Dox) exhibits a high efficacy in the treatment of numerous types of cancer. However, the beneficial cytotoxic effects of Dox are often accompanied by an increase in the risk of cardiotoxicity. Oxidative stress (OS) plays a key role in Dox‑induced cardiomyopathy (DIC). OS in cardiomyocytes disrupts endoplasmic reticulum (ER) function, leading to the accumulation of misfolded/unfolded proteins known as ER stress. ER stress acts as an adaptive mechanism; however, prolonged ER stress together with OS may lead to the initiation of cardiomyocyte apoptosis. The present study aimed to explore the potential of an anti‑diabetic drug, empagliflozin (EMPA), in mitigating Dox‑induced ER stress and cardiomyocyte apoptosis. In the present study, the effects of 1 h pretreatment of EMPA on Dox‑treated cardiomyocytes isolated from Sprague‑Dawley rats were investigated. After 24 h, EMPA pre‑treatment promoted cell survival in the EMPA + Dox group compared with the Dox group. Results of the present study also demonstrated that EMPA mitigated overall ER stress, as the increased expression of ER stress markers was reduced in the EMPA + Dox group. Additionally, OS, inflammation and expression of ER stress apoptotic proteins were also significantly reduced following EMPA pre‑treatment in the EMPA + Dox group. Thus, EMPA may exert beneficial effects on Dox‑induced ER stress and may exhibit potential changes that can be utilised to further evaluate the role of EMPA in mitigating DIC.

Higher pNRF2, SOCS3, IRF3, and RIG1 Tissue Protein Expression in NASH Patients versus NAFL Patients: pNRF2 Expression Is Concomitantly Associated with Elevated Fasting Glucose Levels

Non-alcoholic fatty liver disease (NAFLD) embraces simple steatosis in non-alcoholic fatty liver (NAFL) to advanced non-alcoholic steatohepatitis (NASH) associated with inflammation, fibrosis, and cirrhosis. NAFLD patients often have metabolic syndrome and high risks of cardiovascular and liver-related mortality. Our aim was to clarify which proteins play a role in the progression of NAFL to NASH. The study investigates paraffin-embedded samples of 22 NAFL and 33 NASH patients. To detect potential candidates, samples were analyzed by immunohistochemistry for the proteins involved in innate immune regulation, autophagy, apoptosis, and antioxidant defense: IRF3, RIG-1, SOCS3, pSTAT3, STX17, SGLT2, Ki67, M30, Caspase 3, and pNRF2. The expression of pNRF2 immunopositive nuclei and SOCS3 cytoplasmic staining were higher in NASH than in NAFL (p = 0.001); pNRF2 was associated with elevated fasting glucose levels. SOCS3 immunopositivity correlated positively with RIG1 (r = 0.765; p = 0.001). Further, in NASH bile ducts showed stronger IRF3 immunostaining than in NAFL (p = 0.002); immunopositive RIG1 tissue was higher in NASH than in NAFL (p = 0.01). Our results indicate that pNRF2, SOCS3, IRF3, and RIG1 are involved in hepatic lipid metabolism. We suggest that they may be suitable for further studies to assess their potential as therapeutics.

The Effects of Sodium-Glucose Cotransporter 2-Inhibitors on Steatosis and Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease or Steatohepatitis and Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials

Type 2 Diabetes Mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD) are part of metabolic syndrome and share multiple causal associations. Both conditions have an alarmingly increasing incidence and lead to multiple complications, which have an impact on a variety of organs and systems, such as the kidneys, eyes, and nervous and cardiovascular systems, or may cause metabolic disruptions. Sodium-glucose cotransporter 2-inhibitors (SGLT2-i), as an antidiabetic class with well-established cardiovascular benefits, and its class members have also been studied for their presumed effects on steatosis and fibrosis improvement in patients with NAFLD or non-alcoholic steatohepatitis (NASH). The MEDLINE and Cochrane databases were searched for randomized controlled trials examining the efficacy of SGLT2-i on the treatment of NAFLD/NASH in patients with T2DM. Of the originally identified 179 articles, 21 articles were included for final data analysis. Dapagliflozin, empagliflozin, and canagliflozin are some of the most used and studied SGLT2-i agents which have proven efficacy in treating patients with NAFLD/NASH by addressing/targeting different pathophysiological targets/mechanisms: insulin sensitivity improvement, weight loss, especially visceral fat loss, glucotoxicity, and lipotoxicity improvement or even improvement of chronic inflammation. Despite the considerable variability in study duration, sample size, and diagnostic method, the SGLT2-i agents used resulted in improvements in non-invasive markers of steatosis or even fibrosis in patients with T2DM. This systematic review offers encouraging results that place the SGLT2-i class at the top of the therapeutic arsenal for patients diagnosed with T2DM and NAFLD/NASH.

Relevance of Sugar Transport across the Cell Membrane

Sugar transport through the plasma membrane is one of the most critical events in the cellular transport of nutrients; for example, glucose has a central role in cellular metabolism and homeostasis. The way sugars enter the cell involves complex systems. Diverse protein systems participate in the membrane traffic of the sugars from the extracellular side to the cytoplasmic side. This diversity makes the phenomenon highly regulated and modulated to satisfy the different needs of each cell line. The beautiful thing about this process is how evolutionary processes have diversified a single function: to move glucose into the cell. The deregulation of these entrance systems causes some diseases. Hence, it is necessary to study them and search for a way to correct the alterations and utilize these mechanisms to promote health. This review will highlight the various mechanisms for importing the valuable sugars needed to create cellular homeostasis and survival in all kinds of cells.