SGLT-2 inhibitors as promising therapeutics for non-alcoholic fatty liver disease: pathophysiology, clinical outcomes, and future directions

Adipose tissue in cortisol excess: What Cushing's syndrome can teach us?

Endogenous Cushing's syndrome (CS) is a rare condition due to prolonged exposure to elevated circulating cortisol levels that features its typical phenotype characterised by moon face, proximal myopathy, easy bruising, hirsutism in females and a centripetal distribution of body fat. Given the direct and indirect effects of hypercortisolism, CS is a severe disease burdened by increased cardio-metabolic morbidity and mortality in which visceral adiposity plays a leading role. Although not commonly found in clinical setting, endogenous CS is definitely underestimated leading to delayed diagnosis with consequent increased rate of complications and reduced likelihood of their reversal after disease control. Most of all, CS is a unique model for systemic impairment induced by exogenous glucocorticoid therapy that is commonly prescribed for a number of chronic conditions in a relevant proportion of the worldwide population. In this review we aim to summarise on one side, the mechanisms behind visceral adiposity and lipid metabolism impairment in CS during active disease and after remission and on the other explore the potential role of cortisol in promoting adipose tissue accumulation.

Association between hypoglycemic agent use and the risk of occurrence of nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD) is a growing health concern with increasing prevalence and associated health impacts. Although no approved drugs are available for the NAFLD treatment, several hypoglycemic agents have been investigated as promising therapeutic agents. We aimed to compare the risk of occurrence of NAFLD with respect to the use of different hypoglycemic agents in patients with type 2 diabetes. This retrospective cohort study used data from the National Health Insurance Service-National Sample Cohort of South Korea. Participants newly diagnosed with type 2 diabetes (2003-2019) were included in this study. Two new user-active comparator cohorts were assembled: Cohort 1, new users of thiazolidinediones (TZD) and dipeptidyl peptidase-4 inhibitors (DPP-4i), and Cohort 2, new users of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and DPP-4i. The occurrence of NAFLD was defined based claims that include diagnostic codes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models in 1:3 propensity score (PS)-matched cohorts. For 65,224 patients newly diagnosed with type 2 diabetes, the overall prevalence of NAFLD was 42.6%. The PS-matched Cohort 1 included 6,351 and 2,117 new users of DPP-4i and TZD, respectively. Compared to DPP-4i, TZD use was associated with the decreased risk of NAFLD (HR, 0.66; 95% CI: 0.55-0.78). Cohort 2 consisted of 6,783 and 2,261 new users of DPP-4i and SGLT-2i, respectively; SGLT-2i use was associated with a decreased risk of NAFLD (HR, 0.93; 95% CI: 0.80-1.08). This population-based cohort study supports the clinical implications of prioritizing TZD and SGLT-2i over DPP-4i in reducing the risk of occurrence of NAFLD in patients with type 2 diabetes. However, the findings lacked statistical significance, highlighting the need for further verification studies.

The Ketogenic Effect of SGLT-2 Inhibitors-Beneficial or Harmful?

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors, also called gliflozins or flozins, are a class of drugs that have been increasingly used in the management of type 2 diabetes mellitus (T2DM) due to their glucose-lowering, cardiovascular (CV), and renal positive effects. However, recent studies suggest that SGLT-2 inhibitors might also have a ketogenic effect, increasing ketone body production. While this can be beneficial for some patients, it may also result in several potential unfavorable effects, such as decreased bone mineral density, infections, and ketoacidosis, among others. Due to the intricate and multifaceted impact caused by SGLT-2 inhibitors, this initially anti-diabetic class of medications has been effectively used to treat both patients with chronic kidney disease (CKD) and those with heart failure (HF). Additionally, their therapeutic potential appears to extend beyond the currently investigated conditions. The objective of this review article is to present a thorough summary of the latest research on the mechanism of action of SGLT-2 inhibitors, their ketogenesis, and their potential synergy with the ketogenic diet for managing diabetes. The article particularly discusses the benefits and risks of combining SGLT-2 inhibitors with the ketogenic diet and their clinical applications and compares them with other anti-diabetic agents in terms of ketogenic effects. It also explores future directions regarding the ketogenic effects of SGLT-2 inhibitors.

RNA-Seq transcriptomic landscape profiling of spontaneously hypertensive rats treated with a sodium-glucose cotransporter 2 (SGLT2) inhibitor

BACKGROUND

Sodium-glucose co-transporter-2 inhibitor (SGLT2i) are antihyperglycemic medications that reduce cardiovascular disease (CVD) and improve chronic kidney disease prognosis in patients with diabetes mellitus. The specific impact of SGLT2i treatment on hypertensive individuals, however, remains to be established. This underscores the need for systematic efforts to profile the molecular landscape associated with SGLT2i administration.

METHODS

We conducted a detailed RNA-sequencing (RNA-Seq)-based exploration of transcriptomic changes in response to empagliflozin in eight different tissues (i.e., atrium, aorta, ventricle, white adipose, brown adipose, kidney, lung, and brain) from a male rat model of spontaneously hypertension. Corresponding computational analyses (i.e., clustering, differentially-expressed genes [DEG], and functional association) were performed to analyze these data. Blood pressure measurements, tissue staining studies and RT-qPCR were performed to validate our in silico findings.

RESULTS

We discovered that empagliflozin exerted potent transcriptomic effects on various tissues, most notably the kidney, white adipose, and lung in spontaneously hypertension rats (SHR). The functional enrichment of DEGs indicated that empagliflozin may regulate blood pressure, blood glucose and lipid homeostasis in SHR. Consistent with our RNA-Seq findings, immunohistochemistry and qPCR analyses revealed decreased renal expression of mitogen-activated protein kinase 10 (MAPK10) and decreased pulmonary expression of the proinflammatory factors Legumain and cathepsin S (CTSS) at 1 month of empagliflozin administration. Notably, immunofluorescence experiments showed increased expression of the AMP-activated protein kinases Prkaa1 and Prkaa2 in white adipose tissue of SHR following empagliflozin therapy. Furthermore, the transcriptomic signatures of the blood pressure-lowing effect by empagliflozin were experimentally validated in SHR.

CONCLUSIONS

This study provided an important resource of the effects of empagliflozin on various tissues of SHRs. We identified tissue-specific and tissue-enriched transcriptomic signatures, and uncovered the beneficial effects of empagliflozin on hypertension, weight gain and inflammatory response in validated experiments.

Characterization of the SGLT2 Interaction Network and Its Regulation by SGLT2 Inhibitors: A Bioinformatic Analysis

Background: Sodium–glucose cotransporter 2 (SGLT2), also known as solute carrier family 5 member 2 (SLC5A2), is a promising target for a new class of drugs primarily established as kidney-targeting, effective glucose-lowering agents used in diabetes mellitus (DM) patients. Increasing evidence indicates that besides renal effects, SGLT2 inhibitors (SGLT2i) have also a systemic impact via indirectly targeting the heart and other tissues. Our hypothesis states that the pleiotropic effects of SGLT2i are associated with their binding force, location of targets in the SGLT2 networks, targets involvement in signaling pathways, and their tissue-specific expression.

Methods: Thus, to investigate differences in SGLT2i impact on human organisms, we re-created the SGLT2 interaction network incorporating its inhibitors and metformin and analyzed its tissue-specific expression using publicly available datasets. We analyzed it in the context of the so-called key terms ( autophagy, oxidative stress, aging, senescence, inflammation, AMPK pathways, and mTOR pathways) which seem to be crucial to elucidating the SGLT2 role in a variety of clinical manifestations.

Results: Analysis of SGLT2 and its network components’ expression confidence identified selected organs in the following order: kidney, liver, adipose tissue, blood, heart, muscle, intestine, brain, and artery according to the TISSUES database. Drug repurposing analysis of known SGLT2i pointed out the influence of SGLT1 regulators on the heart and intestine tissue. Additionally, dapagliflozin seems to also have a stronger impact on brain tissue through the regulation of SGLT3 and SLC5A11. The shortest path analysis identified interaction SIRT1-SGLT2 among the top five interactions across six from seven analyzed networks associated with the key terms. Other top first-level SGLT2 interactors associated with key terms were not only ADIPOQ, INS, GLUT4, ACE, and GLUT1 but also less recognized ILK and ADCY7. Among other interactors which appeared in multiple shortest-path analyses were GPT, COG2, and MGAM. Enrichment analysis of SGLT2 network components showed the highest overrepresentation of hypertensive disease, DM-related diseases for both levels of SGLT2 interactors. Additionally, for the extended SGLT2 network, we observed enrichment in obesity (including SGLT1), cancer-related terms, neuroactive ligand–receptor interaction, and neutrophil-mediated immunity.

Conclusion: This study provides comprehensive and ranked information about the SGLT2 interaction network in the context of tissue expression and can help to predict the clinical effects of the SGLT2i.

Role of Sodium-Glucose Co-Transporter 2 Inhibitors in the Regulation of Inflammatory Processes in Animal Models

Sodium-glucose co-transporter 2 inhibitors, also known as gliflozins, were developed as a novel class of anti-diabetic agents that promote glycosuria through the prevention of glucose reabsorption in the proximal tubule by sodium-glucose co-transporter 2. Beyond the regulation of glucose homeostasis, they resulted as being effective in different clinical trials in patients with heart failure, showing a strong cardio-renal protective effect in diabetic, but also in non-diabetic patients, which highlights the possible existence of other mechanisms through which gliflozins could be exerting their action. So far, different gliflozins have been approved for their therapeutic use in T2DM, heart failure, and diabetic kidney disease in different countries, all of them being diseases that have in common a deregulation of the inflammatory process associated with the pathology, which perpetuates and worsens the disease. This inflammatory deregulation has been observed in many other diseases, which led the scientific community to have a growing interest in the understanding of the biological processes that lead to or control inflammation deregulation in order to be able to identify potential therapeutic targets that could revert this situation and contribute to the amelioration of the disease. In this line, recent studies showed that gliflozins also act as an anti-inflammatory drug, and have been proposed as a useful strategy to treat other diseases linked to inflammation in addition to cardio-renal diseases, such as diabetes, obesity, atherosclerosis, or non-alcoholic fatty liver disease. In this work, we will review recent studies regarding the role of the main sodium-glucose co-transporter 2 inhibitors in the control of inflammation.

Combination of tofogliflozin and pioglitazone for NAFLD: Extension to the ToPiND randomized controlled trial

The incidence of nonalcoholic fatty liver disease (NAFLD) has recently increased and is related to obesity and the associated surge in type 2 diabetes mellitus (T2DM) and metabolic syndromes. This trial follows up on our previous work and forms part of the ToPiND study. We aimed to combine tofogliflozin and pioglitazone treatment for hepatic steatosis in patients with NAFLD and T2DM. In this open‐label, prospective, single‐center, randomized clinical trial, patients with NAFLD with T2DM and a hepatic fat fraction of ≥10% were assessed based on magnetic resonance imaging proton density fat fraction. Eligible patients received either 20 mg tofogliflozin or 15–30 mg pioglitazone orally, once daily for 24 weeks, followed by combination therapy with both medicines for an additional 24 weeks. The effects on diabetes mellitus and hepatic steatosis were examined at baseline and after the completion of monotherapy and combination therapy. Thirty‐two eligible patients received the combination therapy of tofogliflozin and pioglitazone. The combination therapy showed additional improvement in glycated hemoglobin compared with each monotherapy group and showed improvement in steatosis, hepatic stiffness, and alanine aminotransferase levels compared with the tofogliflozin monotherapy group. Pioglitazone monotherapy–mediated increase in body weight decreased following concomitant use of tofogliflozin. The combination therapy resulted in lower triglyceride, higher high‐density lipoprotein cholesterol, higher adiponectin, and higher ketone body levels. Conclusion: In addition to the additive effects of tofogliflozin and pioglitazone in patients with T2DM and NAFLD, combination therapy was suggested to reduce weight gain and induce cardioprotective effect. Further studies with more patients are needed to investigate the combination therapy of various drugs.

Empagliflozin Reduces the Progression of Hepatic Fibrosis in a Mouse Model and Inhibits the Activation of Hepatic Stellate Cells via the Hippo Signalling Pathway

Hepatic fibrosis is the excessive production and deposition of the extracellular matrix, resulting in the activation of the fibrogenic phenotype of hepatic stellate cells (HSCs). The Hippo/Yes-associated protein (YAP) signalling pathway is a highly conserved kinase cascade that is critical in regulating cell proliferation, differentiation, and survival, and controls stellate cell activation. Empagliflozin, a sodium-glucose cotransporter type-2 inhibitor, is an antidiabetic drug that may prevent fibrotic progression by reducing hepatic steatosis and inflammation. However, little is known about its mechanism of action in liver fibrosis. In this study, we used male C57 BL/6 J mice fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) as a model for hepatic fibrosis. For 5 weeks, the mice received either a vehicle or empagliflozin based on their assigned group. Empagliflozin attenuated CDAHFD-induced liver fibrosis. Thereafter, we identified the Hippo pathway, along with its effector, YAP, as a key pathway in the mouse liver. Hippo signalling is inactivated in the fibrotic liver, but empagliflozin treatment activated Hippo signalling and decreased YAP activity. In addition, empagliflozin downregulated the expression of pro-fibrogenic genes and activated Hippo signalling in HSCs. We identified a mechanism by which empagliflozin ameliorates liver fibrosis.

Effects of SGLT2 inhibitors on haematocrit and haemoglobin levels and the associated cardiorenal benefits in T2DM patients: A meta-analysis

To explore the effect and magnitude of effect of sodium-glucose cotransporter-2 (SGLT2) inhibitors on haematocrit and haemoglobin and the related cardiorenal benefits in patients with type 2 diabetes mellitus (T2DM), PubMed, Web of Science, CENTRAL and EMBASE were searched to identify eligible trials. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Seventy-eight studies were included in the meta-analysis. SGLT2 inhibitors significantly increased haematocrit and haemoglobin levels compared with control (total WMD 2.27% [95% CI 2.08, 2.47] and 6.20 g/L [95% CI 5.68, 6.73], respectively). Except for dapagliflozin (p = 0.000), no notable dose-dependent relationship was revealed for other SGLT2 inhibitors. The effect could be sustained or even slightly increased with long-term therapy (coef. =0.009, 95% CI [0.005, 0.013], p = 0.000). In subgroup analyses, haematocrit elevation increased with higher body mass index (BMI). A greater haematocrit elevation could be observed in white patients or when compared with active controls. In conclusion, SGLT2 inhibitors increased haematocrit and haemoglobin levels in T2DM patients. Changes in haematocrit and haemoglobin seem to be surrogate markers of improvement in renal metabolic stress, and important mediators involved in cardiorenal protection.

Different Responses of Muscle Sympathetic Nerve Activity to Dapagliflozin Between Patients With Type 2 Diabetes With and Without Heart Failure

Background Sodium-glucose cotransporter 2 inhibitors improve cardiovascular outcomes in patients with diabetes with and without heart failure (HF). However, their influence on sympathetic nerve activity (SNA) remains unclear. The purpose of this study was to evaluate the effect of sodium-glucose cotransporter 2 inhibitors on SNA and compare the responses of SNA to sodium-glucose cotransporter 2 inhibitors in patients with type 2 diabetes with and without HF. Methods and Results Eighteen patients with type 2 diabetes, 10 with HF (65.4±3.68 years) and 8 without HF (63.3±3.62 years), were included. Muscle SNA (MSNA), heart rate, and blood pressure were recorded before and 12 weeks after administration of dapagliflozin (5 mg/day). Sympathetic and cardiovagal baroreflex sensitivity were simultaneously calculated. Brain natriuretic peptide level increased significantly at baseline in patients with HF than those without HF, while MSNA, blood pressure, and hemoglobin A1c did not differ between the 2 groups. Fasting blood glucose and homeostatic model assessment of insulin resistance did not change in either group after administering dapagliflozin. MSNA decreased significantly in both groups. However, the reduction in MSNA was significantly higher in patients with HF than patients with non-HF (-20.2±3.46 versus -9.38±3.65 bursts/100 heartbeats; P=0.049), which was concordant with the decrease in brain natriuretic peptide. Conclusions Dapagliflozin significantly decreased MSNA in patients with type 2 diabetes regardless of its blood glucose-lowering effect. Moreover, the reduction in MSNA was more prominent in patients with HF than in patients with non-HF. These results indicate that the cardioprotective effects of sodium-glucose cotransporter 2 inhibitors may, in part, be attributed to improved SNA.

Impact of SGLT2 Inhibitors on Heart Failure: From Pathophysiology to Clinical Effects

Heart failure (HF) affects up to over 20% of patients with type 2 diabetes (T2DM), even more in the elderly. Although, in T2DM, both hyperglycemia and the proinflammatory status induced by insulin resistance are crucial in cardiac function impairment, SGLT2i cardioprotective mechanisms against HF are several. In particular, these beneficial effects seem attributable to the significant reduction of intracellular sodium levels, well-known to exert a cardioprotective role in the prevention of oxidative stress and consequent cardiomyocyte death. From a molecular perspective, patients’ exposure to gliflozins’ treatment mimics nutrient and oxygen deprivation, with consequent autophagy stimulation. This allows to maintain the cellular homeostasis through different degradative pathways. Thus, since their introduction in the clinical practice, the hypotheses on SGLT2i mechanisms of action have changed: from simple glycosuric drugs, with consequent glucose lowering, erythropoiesis enhancing and ketogenesis stimulating, to intracellular sodium-lowering molecules. This provides their consequent cardioprotective effect, which justifies its significant reduction in CV events, especially in populations at higher risk. Finally, the updated clinical evidence of SGLT2i benefits on HF was summarized. Thus, this review aimed to analyze the cardioprotective mechanisms of sodium glucose transporter 2 inhibitors (SGLT2i) in patients with HF, as well as their clinical impact on cardiovascular events.

Empagliflozin therapy and insulin resistance-associated disorders: effects and promises beyond a diabetic state

Empagliflozin is a SGLT2 inhibitor that has shown remarkable cardiovascular and renal activities in patients with type 2 diabetes (T2D). Preclinical and clinical studies of empagliflozin in T2D population have demonstrated significant improvements in body weight, waist circumference, insulin sensitivity, and blood pressure – effects beyond its antihyperglycaemic control. Moreover, several studies suggested that this drug possesses significant anti-inflammatory and antioxidative stress properties. This paper explores extensively the main preclinical and clinical evidence of empagliflozin administration in insulin resistance-related disorders beyond a diabetic state. It also discusses its future perspectives, as a therapeutic approach, in this high cardiovascular-risk population.

Zingerone Administered Neonatally Prevents the Subsequent Development of High Dietary Fructose-Induced Fatty Liver in Sprague Dawley Rats

Consumption of high-fructose diets early in life increases the risk of developing metabolic disorders, including nonalcoholic fatty liver disease (NAFLD). Zingerone, an alkaloid isolated from Zingiber officinale, has been demonstrated to reverse obesity and fatty liver in adult male rats. We investigated the potential preventive effects of neonatally administered zingerone on the development of fructose-induced NAFLD in male and female rats. Four-day-old male (n = 35) and female (n = 44) rat pups were randomized and gavaged with: 10 mL/kg body weight (bwt) of distilled water (C), 10 mL/kg bwt of 20% fructose solution (Fr), 10 mL/kg bwt of 20% fructose solution +40 mg/kg bwt of zingerone (ZFr), and 40 mg/kg bwt of zingerone (Z) daily for 14 days. After weaning, all groups continued on unlimited standard rat feed; however, groups C and Z had plain drinking water, whereas groups Fr and ZFr had unlimited 20% fructose solution to drink for 10 weeks. Rats on the high-fructose diet (Fr) compared with the negative controls (C) had significantly increased hepatic lipid content (in %, males: P = .0002; females: P < .0001, analysis of variance [ANOVA]) and hepatic steatosis score (in %, males: P = .0018; females: P < .0022, Kruskal-Wallis ANOVA). Zingerone prevented (P < .05) the fructose-induced increase in hepatic steatosis in both sexes. The plasma alanine aminotransferase activity, levels of uric acid, TBARS (thiobarbituric acid reactive substances), IL-6 (interleukin-6), and TNF-α (tumor necrosis factor alpha) were not different (P > .05, ANOVA) across the different treatment groups in both sexes. No difference (P > .05, ANOVA) was observed between the two sexes for treatment, sex and interaction effects with regard to hepatic lipid content, and measured blood parameters. The use of zingerone neonatally should be further investigated as a strategic prophylactic intervention for the prevention of long-term high-fructose diet-induced NAFLD.

Efficacy of Sodium-Glucose Cotransporter 2 Inhibitors in Patients With Concurrent Type 2 Diabetes Mellitus and Non-Alcoholic Steatohepatitis: A Review of the Evidence

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, and more than half of individuals diagnosed with type 2 diabetes concurrently present with NAFLD. There is a bidirectional pathological relationship between the two conditions, whereby NAFLD increases the risk of type 2 diabetes, and type 2 diabetes contributes to and accelerates the progression of NAFLD. Furthermore, over 30% of patients with NAFLD progress to non-alcoholic liver steatohepatitis (NASH), which then increases the risk of cirrhosis and hepatocellular carcinoma. Despite its high prevalence and the potential clinical implications, the underlying pathogenesis of NAFLD has yet to be fully elucidated, and there is no consensus regarding standard diagnosis and treatment for either NALFD or NASH. As patients with both NASH and type 2 diabetes have impaired hepatic function owing to chronic inflammation and the resulting structural changes caused by hepatic fat accumulation, they face reduced options for antidiabetic treatment. SGLT-2 inhibitors inhibit glucose reabsorption in the proximal tubule, with increased excretion of glucose in urine and decreased glucose levels in plasma, and their glycemia-lowering effect is insulin-independent. Several other beneficial effects have been reported for SGLT-2 inhibitors, including reduced risks of cardiovascular and renal diseases, improved blood pressure control, body weight reduction, and reductions in liver fat content. Experimental studies in mouse models have suggested that SGLT-2 inhibitors may have beneficial modulatory effects on NAFLD/NASH. Several trials in patients with type 2 diabetes have also suggested that these drugs may be useful in treating both type 2 diabetes and NAFLD or NASH. However, further research is needed to identify the mechanisms by which SGLT-2 inhibitors affect fatty liver and steatohepatitis. In this state-of-the-art review, we explore the literature on the efficacy of SGLT-2 inhibitors in patients with type 2 diabetes and NASH, and present arguments for and against the use of SGLT-2 inhibitors in this patient population.

A look to the future in non-alcoholic fatty liver disease: Are glucagon-like peptide-1 analogues or sodium-glucose co-transporter-2 inhibitors the answer?

The increasing prevalence of diabetes and non-alcoholic fatty liver disease (NAFLD) is a growing public health concern associated with significant morbidity, mortality and economic cost, particularly in those who progress to cirrhosis. Medical treatment is frequently limited, with no specific licensed treatments currently available for people with NAFLD. Its association with diabetes raises the possibility of shared mechanisms of disease progression and treatment. With the ever-growing interest in the non-glycaemic effects of diabetes medications, studies and clinical trials have investigated hepatic outcomes associated with the use of drug classes used for people with type 2 diabetes (T2D), such as glucagon-like peptide-1 (GLP-1) analogues or sodium-glucose co-transporter-2 (SGLT2) inhibitors. Studies exploring the use of GLP-1 analogues or SGLT2 inhibitors in people with NAFLD have observed improved measures of hepatic inflammation, liver enzymes and radiological features over short periods. However, these studies tend to have variable study populations and inconsistent reported outcomes, limiting comparison between drugs and drug classes. As these drugs appear to improve biomarkers of NAFLD, clinicians should consider their use in patients with NAFLD and T2D. However, further evidence with greater participant numbers and longer trial durations is required to support specific licensing for people with NAFLD. Larger trials would allow reporting of major adverse hepatic events, akin to cardiovascular and renal outcome trials, to be determined. This would provide a more meaningful evaluation of the impact of these drugs in NAFLD. Nevertheless, these drugs represent a future potential therapeutic avenue in this difficult-to-treat population and may beget significant health and economic impacts.

Hsa_circ_0048179 attenuates free fatty acid-induced steatosis via hsa_circ_0048179/miR-188-3p/GPX4 signaling

Although circular RNAs (circRNAs) are known to play key roles in non-alcoholic fatty liver disease, much about their targets and mechanisms remains unknown. We therefore investigated the actions and mechanisms of hsa_circ_0048179 in an in vitro model of NAFLD. HepG2 cells were exposed to oleate/palmitate (2:1 ratio) for 24 h to induce intracellular lipid accumulation. Using CCK-8 assays, flow cytometry, fluorescence microscopy, western blotting, RT-qPCR, and Oil red O staining, we found that oleate/palmitate treatment reduced cell viability while increasing apoptosis and lipid accumulation in HepG2 cells. Levels of the antioxidant enzyme GPX4 were decreased in oleate/palmitate-treated HepG2 cells, and there were corresponding increases in reactive oxygen species and damage to mitochondrial cristae. Levels of hsa_circ_0048179 expression were also suppressed by oleate/palmitate treatment, and GPX4 levels were markedly increased in HepG2 cells following transfection with hsa_circ_0048179. Analysis of its mechanism revealed that hsa_circ_0048179 upregulated GPX4 levels by acting as a competitive “sponge” of miR-188-3p and that hsa_circ_0048179 attenuated oleate/palmitate-induced lipid accumulation in HepG2 cells by sponging miR-188-3p. Collectively, our findings suggest that hsa_circ_0048179 may play a key role in the pathogenesis of steatosis and may thus be a useful target for drug development.

Effect of Empagliflozin on Liver Steatosis and Fibrosis in Patients With Non-Alcoholic Fatty Liver Disease Without Diabetes: A Randomized, Double-Blind, Placebo-Controlled Trial

Introduction

Despite the high prevalence of non-alcoholic fatty liver disease (NAFLD) and its associated co-morbidities, no efficient treatment in a high percentage of individuals is available. Beneficial effects of sodium–glucose co-transporter 2 inhibitors on fatty liver have been investigated in people with type 2 diabetes (T2DM). The aim of this study was to explore the effect of empagliflozin on liver steatosis and fibrosis in patients with NAFLD without T2DM.

Methods

In this prospective randomized, double-blind, placebo-controlled clinical trial, participants with NAFLD were randomized to empagliflozin (10 mg/day) (n = 43) or placebo (n = 47) for 24 weeks. Hepatic steatosis and fibrosis were assessed using transient elastography to measure the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). The primary outcome was the change in CAP score at 24 weeks.

Results

There was significant decrease in CAP score in both groups but no significant difference was observed between the two groups (P = 0.396). LSM was significantly decreased in the empagliflozin-treated group (6.03 ± 1.40 to 5.33 ± 1.08 kPa; P = 0.001), while no change was found in the placebo group. In subgroups analysis of patients with significant steatosis at baseline (CAP ≥ 302 dB/m), steatosis significantly improved in the empagliflozin group (37.2% vs. 17%; P = 0.035). There was a significant decrease in the grade of liver fat on visual analysis of ultrasound images, AST, ALT, and fasting insulin levels in the empagliflozin group, while no changes were observed in the placebo group.

Conclusions

Empagliflozin improves liver steatosis and, more importantly, measures of liver fibrosis in patients with NAFLD without T2DM.

Trial registration

ClinicalTrials.gov identifier, IRCT20190122042450N1.

Molecular Mechanisms of SGLT2 Inhibitor on Cardiorenal Protection

The development of sodium-glucose transporter 2 inhibitor (SGLT2i) broadens the therapeutic strategies in treating diabetes mellitus. By inhibiting sodium and glucose reabsorption from the proximal tubules, the improvement in insulin resistance and natriuresis improved the cardiovascular mortality in diabetes mellitus (DM) patients. It has been known that SGLT2i also provided renoprotection by lowering the intraglomerular hypertension by modulating the pre- and post- glomerular vascular tone. The application of SGLT2i also provided metabolic and hemodynamic benefits in molecular aspects. The recent DAPA-CKD trial and EMPEROR-Reduced trial provided clinical evidence of renal and cardiac protection, even in non-DM patients. Therefore, the aim of the review is to clarify the hemodynamic and metabolic modulation of SGLT2i from the molecular mechanism.

Glucocorticoid-Induced Fatty Liver Disease

Glucocorticoids (GCs) are commonly used at high doses and for prolonged periods (weeks to months) in the treatment of a variety of diseases. Among the many side effects are increased insulin resistance with disturbances in glucose/insulin homeostasis and increased deposition of lipids (mostly triglycerides) in the liver. Here, we review the metabolic pathways of lipid deposition and removal from the liver that become altered by excess glucocorticoids. Pathways of lipid deposition stimulated by excess glucocorticoids include 1) increase in appetite and high caloric intake; 2) increased blood glucose levels due to GC-induced stimulation of gluconeogenesis; 3) stimulation of de novo lipogenesis that is augmented by the high glucose and insulin levels and by GC itself; and 4) increased release of free fatty acids from adipose stores and stimulation of their uptake by the liver. Pathways that decrease hepatic lipids affected by glucocorticoids include a modest stimulation of very-low-density lipoprotein synthesis and secretion into the circulation and inhibition of β-oxidation of fatty acids. Role of 11β-hydroxysteroid dehydrogenases-1 and -2 and the reversible conversion of cortisol to cortisone on intracellular levels of cortisol is examined. In addition, GC control of osteocalcin expression and the effect of this bone-derived hormone in increasing insulin sensitivity are discussed. Finally, research focused on gaining a better understanding of the dose and duration of treatment with glucocorticoids, which leads to increased triglyceride deposition in the liver, and the reversibility of the condition is highlighted.

Dapagliflozin Suppresses Hepcidin And Increases Erythropoiesis

CONTEXT

Dapagliflozin and other SGLT2 inhibitors are known to increase hematocrit, possibly due to its diuretic effects and hemoconcentration.

OBJECTIVE

Since type 2 diabetes is a proinflammatory state and since hepcidin, a known suppressor of erythropoiesis, is increased in proinflammatory states, we investigated the possibility that dapagliflozin suppresses hepcidin concentrations and thus increases erythropoiesis.

DESIGN

Prospective, randomized, and placebo-controlled study.

SETTING

Single endocrinology center.

PATIENTS

Fifty-two obese type 2 diabetes patients.

INTERVENTION

Patients were randomized (1:1) to either dapagliflozin (10 mg daily) or placebo for 12 weeks. Blood samples were collected before and after treatments and serum, plasma, and mononuclear cells (MNC) were prepared.

MAIN OUTCOME MEASURE

Hepcidin and other hematopoietic factors.

RESULTS

Following dapagliflozin treatment, there was a significant fall in HbA1c and a significant increase in hemoglobin concentration and hematocrit. Dapagliflozin treatment significantly reduced circulating hepcidin and ferritin concentrations while causing a significant increase in levels of the hepcidin inhibitor, erythroferrone, and a transient increase in erythropoietin. Additionally, dapagliflozin increased plasma transferrin levels and expression of transferrin receptors 1 and 2 in MNC, while there was no change in the expression of the iron cellular transporter, ferroportin. Dapagliflozin treatment also caused a decrease in hypoxia-induced factor-1α expression in MNC while it increased the expression of its inhibitor, prolyl hydroxylase-2. There were no significant changes in any of these indices in the placebo group.

CONCLUSIONS

We conclude that dapagliflozin increases erythropoiesis and hematocrit through mechanisms that involve the suppression of hepcidin and the modulation of other iron regulatory proteins.

Adverse Effects of Glycemia-Lowering Medications in Type 2 Diabetes

PURPOSE OF REVIEW

Treatment of patients with type 2 diabetes mellitus is focused on preventing the occurrence and delaying the development of macro- and micro-vascular complications. Glycemic control can help prevent these complications, but there is concern about the adverse effects of glycemia-lowering medications. A rational approach is to balance the desired low risk of adverse events against the unwanted higher risk of major complications resulting from suboptimal glucose control.

RECENT FINDINGS

Using the above approach, approved glucose-lowering agents have favorable benefit-to-risk profiles for use in most patients with type 2 diabetes. We first briefly review the mechanism of actions and benefits of the different commonly used classes of glycemia-lowering medications and then discuss adverse effects and safety concern associated with their use. Our overall assessment is that if used appropriately, the different classes of glycemia-lowering medications offer beneficial outcomes with relatively modest and, in some instances, preventable adverse events.