Nonalcoholic Fatty Liver Disease: A Drug Revolution Is Coming

Update on the clinical applications of SGLTis: Insight to benefits beyond hypoglycemic and cardiorenal protection

Sodium glucose cotransporter inhibitor (SGLTi) drugs have been widely used in clinical practice. In addition to their benefits in hyperglycemia, heart failure (HF), and kidney disease, their effects on obesity, metabolic dysfunction-associated steatotic liver disease (MASLD, formerly named nonalcoholic fatty liver disease [NAFLD]), polycystic ovarian syndrome (PCOS), abnormal lipid metabolism, hyperuricemia, obstructive sleep apnea syndrome (OSAS), anemia, and syndrome of inappropriate antidiuresis (SIAD, formerly named syndrome of inappropriate antidiuretic hormone [SIADH]) have been explored. In this review, we searched the data of clinical randomized controlled trials (RCTs) and meta-analyses of SGLTis in patients with diabetes from the PubMed library between January 1, 2020, and February 1, 2024. According to our review, certain SGLTis exhibit relatively superior clinical safety and effectiveness for treating the abovementioned diseases. Proper utilization of SGLTis in these patients can provide additional medication options for patients with different disease scenarios. However, studies of SGLTis in these diseases are relatively rare, with shortcomings such as small sample sizes and short intervention periods. Therefore, further large-scale, long-term, well-designed studies are needed to clarify the findings.

Effect of bariatric surgery on NAFLD/NASH: a single-centre observational prospective cohort study

INTRODUCTION

The prevalence of non-alcoholic fatty liver disease (NAFLD) ranges from 25% in the general population to 90% in patients with obesity scheduled for bariatric surgery. NAFLD can progress towards non-alcoholic steatohepatitis (NASH) associated with complications such as cirrhosis, hepatocellular carcinoma and cardiovascular disease. To date, losing weight and lifestyle modifications are the best known treatments for NASH. Bariatric surgery significantly improves NAFLD/NASH in the short term. However, the extent of this improvement is not yet clear and long-term data on the natural course of NAFLD/NASH after bariatric surgery are lacking. The factors involved in NAFLD/NASH regression after bariatric surgery have not been elucidated.

METHODS AND ANALYSIS

This is an observational prospective cohort study including patients scheduled for bariatric surgery. Extensive metabolic and cardiovascular analyses will be carried out including measurements of carotid intima media thickness and pulse wave velocity. Genomic, proteomic, lipidomic and metabolomic studies will be done. Microbioma analyses before and 1 year after surgery will be done. Transient elastography measurements will be performed before and at 1, 3 and 5 years after surgery. For those with an elevated preoperative transient elastography measurement by Fibroscan, a laparoscopic liver biopsy will be performed during surgery. Primary outcome measures are the change of steatosis and liver fibrosis 5 years after surgery. Secondary outcome measure is the comparison of the transient elastography measurements with the NAFLD Activity Score from the biopsies.

ETHICS AND DISSEMINATION

The protocol has been approved by the Medical Research Ethics Committees United, Nieuwegein, on 1 March 2022 (registration code R21.103/NL79423.100.21). The study results will be submitted for publication in peer-reviewed journals and data will be presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05499949.

Increased expression of sodium-glucose cotransporter 2 and O-GlcNAcylation in hepatocytes drives non-alcoholic steatohepatitis

AIMS

Steatosis reducing effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors in non-alcoholic steatohepatitis (NASH) has been consistently reported in humans, but their mechanism remains uncertain. In this study, we examined the expression of SGLT2 in human livers and investigated the crosstalk between SGLT2 inhibition and hepatic glucose uptake, intracellular O-GlcNAcylation, and autophagic regulation in NASH.

MATERIALS AND METHODS

Human liver samples obtained from subjects with/without NASH were analyzed. For in vitro studies, human normal hepatocytes and hepatoma cells were treated with SGLT2 inhibitor under high-glucose and high-lipid conditions. NASH in vivo was induced by a high-fat, -fructose, and -cholesterol Amylin liver NASH (AMLN) diet for 10 weeks followed by an additional 10 weeks with/without SGLT2 inhibitor (empagliflozin 10 mg/kg/day).

RESULTS

Liver samples from subjects with NASH were associated with increased SGLT2 and O-GlcNAcylation expression compared with controls. Under NASH condition (in vitro condition with high glucose and lipid), intracellular O-GlcNAcylation and inflammatory markers were increased in hepatocytes and SGLT2 expression was upregulated; SGLT2 inhibitor treatment blocked these changes by directly reducing hepatocellular glucose uptake. In addition, decreased intracellular O-GlcNAcylation by SGLT2 inhibitor promoted autophagic flux through AMPK-TFEB activation. In the AMLN diet-induced NASH mice model, SGLT2 inhibitor alleviated lipid accumulation, inflammation, and fibrosis through autophagy activation related to decreased SGLT2 expression and O-GlcNAcylation in the liver.

CONCLUSIONS

This study firstly demonstrates increased SGLT2 expression in NASH and secondly reveals the novel effect of SGLT2 inhibition on NASH by activating autophagy mediated by inhibition of hepatocellular glucose uptake and consequently decreasing intracellular O-GlcNAcylation.

Metabolic Dysfunction-Associated Fatty Liver Disease and Mortality: A Population-Based Cohort Study

BACKGROUND

We investigated whether metabolic dysfunction-associated fatty liver disease (MAFLD) is associated with an elevated risk of all-cause and cardiovascular mortality using a large-scale health examination cohort.

METHODS

A total of 394,835 subjects in the Kangbuk Samsung Health Study cohort were enrolled from 2002 to 2012. Participants were categorized by the presence of nonalcoholic fatty liver disease (NAFLD) and MAFLD as follows: normal subjects; patients with both NAFLD and MAFLD; patients with NAFLD only; and patients with MAFLD only. Cox proportional hazards models were used to analyze the risk of mortality.

RESULTS

During a median 5.7 years of follow-up, 20.69% was patients with both NAFLD and MAFLD, 1.51% was patients with NAFLD only, and 4.29% was patients with MAFLD only. All-cause and cardiovascular death was higher in patients with MAFLD than those without MAFLD (P<0.001, respectively). In patients with MAFLD only, the hazard ratio (HR) of all-cause and cardiovascular death was 1.35 (95% confidence interval [CI], 1.13 to 1.60) and 1.90 (95% CI, 1.26 to 2.88) after adjusting for age, which lost its statistical significance by multivariable adjustments. Compared to patients with less than two components of metabolic dysfunction, patients with more than two components of metabolic dysfunction were a higher risk of cardiovascular death (HR, 2.05; 95% CI, 1.25 to 3.38) and only women with more than two components of metabolic dysfunction were a higher risk of all-cause death (HR, 1.44; 95% CI, 1.02 to 2.03).

CONCLUSION

MAFLD criteria could identify a high-risk group for all-cause and cardiovascular death.

Lessons on Drug Development: A Literature Review of Challenges Faced in Nonalcoholic Fatty Liver Disease (NAFLD) Clinical Trials

NAFLD is the most common chronic liver disease worldwide, occurring in both obese and lean patients. It can lead to life-threatening liver diseases and nonhepatic complications, such as cirrhosis and cardiovascular diseases, that burden public health and the health care system. Current care is weight loss through diet and exercise, which is a challenging goal to achieve. However, there are no FDA-approved pharmacotherapies for NAFLD. This review thoroughly examines the clinical trial findings from 22 drugs (Phase 2 and above) and evaluates the future direction that trials should take for further drug development. These trialed drugs can broadly be categorized into five groups-hypoglycemic, lipid-lowering, bile-pathway, anti-inflammatory, and others, which include nutraceuticals. The multitude of challenges faced in these yet-to-be-approved NAFLD drug trials provided insight into a few areas of improvement worth considering. These include drug repurposing, combinations, noninvasive outcomes, standardization, adverse event alleviation, and the need for precision medicine with more extensive consideration of NAFLD heterogenicity in drug trials. Understandably, every evolution of the drug development landscape lies with its own set of challenges. However, this paper believes in the importance of always learning from lessons of the past, with each potential improvement pushing clinical trials an additional step forward toward discovering appropriate drugs for effective NAFLD management.

Gemigliptin Alleviates Succinate-Induced Hepatic Stellate Cell Activation by Ameliorating Mitochondrial Dysfunction

BACKGRUOUND

Dipeptidyl peptidase-4 inhibitors (DPP-4Is) are used clinically as oral antidiabetic agents. Although DPP-4Is are known to ameliorate liver fibrosis, the protective mechanism of DPP-4Is in liver fibrosis remains obscure. In this study, gemigliptin was used to investigate the potential of DPP-4Is to alleviate the progression of liver fibrosis.

METHODS

To clarify the effects and mechanisms of gemigliptin, we conducted various experiments in LX-2 cells (immortalized human hepatic stellate cells [HSCs], the principal effectors of hepatic fibrogenesis), which were activated by succinate and exhibited elevated expression of α-smooth muscle actin, collagen type 1, and pro-inflammatory cytokines and increased cell proliferation. In vivo, we examined the effects and mechanisms of gemigliptin on a high-fat, high-cholesterol-induced mouse model of nonalcoholic steatohepatitis (NASH).

RESULTS

Gemigliptin decreased the expression of fibrogenesis markers and reduced the abnormal proliferation of HSCs. In addition, gemigliptin reduced the succinate-induced production of mitochondrial reactive oxygen species (ROS), intracellular ROS, and mitochondrial fission in HSCs. Furthermore, in the mouse model of NASH-induced liver fibrosis, gemigliptin alleviated both liver fibrosis and mitochondrial dysfunction.

CONCLUSION

Gemigliptin protected against HSC activation and liver fibrosis by alleviating mitochondrial dysfunction and ROS production, indicating its potential as a strategy for preventing the development of liver disease.

Inhibition of 11β-hydroxysteroid dehydrogenase 1 relieves fibrosis through depolarizing of hepatic stellate cell in NASH

11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) is a key enzyme that catalyzes the intracellular conversion of cortisone to physiologically active cortisol. Although 11βHSD1 has been implicated in numerous metabolic syndromes, such as obesity and diabetes, the functional roles of 11βHSD1 during progression of nonalcoholic steatohepatitis (NASH) and consequent fibrosis have not been fully elucidated. We found that pharmacological and genetic inhibition of 11βHSD1 resulted in reprogramming of hepatic stellate cell (HSC) activation via inhibition of p-SMAD3, α-SMA, Snail, and Col1A1 in a fibrotic environment and in multicellular hepatic spheroids (MCHSs). We also determined that 11βHSD1 contributes to the maintenance of NF-κB signaling through modulation of TNF, TLR7, ITGB3, and TWIST, as well as regulating PPARα signaling and extracellular matrix accumulation in activated HSCs during advanced fibrogenesis in MCHSs. Of great interest, the 11βHSD1 inhibitor J2H-1702 significantly attenuated hepatic lipid accumulation and ameliorated liver fibrosis in diet- and toxicity-induced NASH mouse models. Together, our data indicate that J2H-1702 is a promising new clinical candidate for the treatment of NASH.

Triglyceride and glucose index is a simple and easy-to-calculate marker associated with nonalcoholic fatty liver disease

OBJECTIVE

The aim of this study was to evaluate the relationship between the triglyceride and glucose (TyG) index and nonalcoholic fatty liver disease (NAFLD) using a large, population-based cohort study database.

METHODS

A total of 52,575 participants were enrolled from 2007 to 2013 in the Kangbuk Samsung Health Study cohort. The presence of NAFLD was ascertained by ultrasonography in the absence of other known liver diseases.

RESULTS

Over a median 5.1 years of follow-up, 7,292 participants (13.87%) were diagnosed with NAFLD. In a multivariate-adjusted model, the hazard ratio for NAFLD of the TyG index was 1.413 (95% CI: 1.349-1.480) in the first 6 months, 1.480 (95% CI: 1.408-1.556) in months 6 to 12, 1.427 (95% CI: 1.370-1.485) in months 12 to 18, and 1.246 (95% CI: 1.159-1.339) in months >18. The hazard ratios of triglycerides, glucose, fatty liver index, and homeostatic model assessment of insulin resistance for NAFLD in months >18 were 1.124 (95% CI: 1.061-1.190), 1.037 (95% CI: 0.970-1.109), 1.508 (95% CI: 1.417-1.605), and 1.177 (95% CI: 1.116-1.242), respectively. The NAFLD-free rate decreased with increasing TyG index quartile (p < 0.001). The TyG index level from which the risk of NAFLD increased appeared to be 8.24.

CONCLUSIONS

This study found that the TyG index is a simple and easy-to-calculate marker associated with NAFLD.

Inflammatory and fibrotic mechanisms in NAFLD-Implications for new treatment strategies

Non-alcoholic fatty liver disease is comprised of either simple steatosis (non-alcoholic fatty liver) or a more advanced inflammatory and fibrogenic stage (non-alcoholic steatohepatitis [NASH]). NASH affects a growing proportion of the global adult and pediatric population, leading to rising rates of liver fibrosis and hepatocellular carcinoma. NASH is a multifactorial disease that is part of a systemic metabolic disorder. Here, we provide an overview of the metabolic underpinnings of NASH pathogenesis and established drivers of inflammation and fibrosis. Clarification of underlying fibrogenic and inflammatory mechanisms will advance the development of novel treatment strategies as there are no approved therapies at present. We discuss emerging experimental approaches and potential novel investigational strategies derived from animal models including the inflammasome, epigenetic reprogramming, Hippo signaling, Notch signaling, engineered T cells to remove fibrogenic HSCs, and HSC-specific targeting therapies. Recently completed and ongoing clinical trials and antifibrotics are discussed, illuminating the growing expectation that one or more therapies will yield clinical benefit in NASH in the coming years.

The New Therapeutic Approaches in the Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease which is characterized by extremely complex pathogenetic mechanisms and multifactorial etiology. Some of the many pathophysiological mechanisms involved in the development of NAFLD include oxidative stress, impaired mitochondrial metabolism, inflammation, gut microbiota, and interaction between the brain-liver-axis and the regulation of hepatic lipid metabolism. The new therapeutic approaches in the treatment of NAFLD are targeting some of these milestones along the pathophysiological pathway and include drugs like agonists of peroxisome proliferator-activated receptors (PPARs), glucagon-like peptide-1 (GLP-1) agonists, sodium/glucose transport protein 2 (SGLT2) inhibitors, farnesoid X receptor (FXR) agonists, probiotics, and symbiotics. Further efforts in biomedical sciences should focus on the investigation of the relationship between the microbiome, liver metabolism, and response to inflammation, systemic consequences of metabolic syndrome.

Effects of intragastric balloon placement in metabolic dysfunction-associated fatty liver disease: A systematic review and meta-analysis

BACKGROUND

Metabolic dysfunction-associated fatty liver disease corresponds to a clinical entity that affects liver function triggered by the accumulation of fat in the liver and is linked with metabolic dysregulation.

AIM

To evaluate the effects of the intragastric balloon (IGB) in patients with metabolic dysfunction-associated fatty liver disease through the assessment of liver enzymes, imaging and several metabolic markers.

METHODS

A comprehensive search was done of multiple electronic databases (MEDLINE, EMBASE, LILACS, Cochrane and Google Scholar) and grey literature from their inception until February 2021. Inclusion criteria involved patients with a body mass index > 25 kg/m² with evidence or previous diagnosis of hepatic steatosis. Outcomes analyzed before and after 6 mo of IGB removal were alanine aminotransferase (IU/L), gamma-glutamyltransferase (IU/L), glycated hemoglobin (%), triglycerides (mg/dL), systolic blood pressure (mmHg), homeostatic model assessment, abdominal circumference (cm), body mass index (kg/m²) and liver volume (cm³).

RESULTS

Ten retrospective cohort studies evaluating a total of 508 patients were included. After 6 mo of IGB placement, this significantly reduced alanine aminotransferase [mean difference (MD): 10.2, 95% confidence interval (CI): 8.12-12.3], gamma-glutamyltransferase (MD: 9.41, 95%CI: 6.94-11.88), glycated hemoglobin (MD: 0.17%, 95%CI: 0.03-0.31), triglycerides (MD: 38.58, 95%CI: 26.65-50.51), systolic pressure (MD: 7.27, 95%CI: 4.79-9.76), homeostatic model assessment (MD: 2.23%, 95%CI: 1.41-3.04), abdominal circumference (MD: 12.12, 95%CI: 9.82-14.41) and body mass index (MD: 5.07, 95%CI: 4.21-5.94).

CONCLUSION

IGB placement showed significant efficacy in improving alanine aminotransferase and gamma-glutamyltransferase levels in patients with metabolic dysfunction-associated fatty liver disease as well as improving metabolic markers related to disease progression.

Allopurinol ameliorates high fructose diet induced hepatic steatosis in diabetic rats through modulation of lipid metabolism, inflammation, and ER stress pathway

Excess fructose consumption contributes to development obesity, metabolic syndrome, and nonalcoholic fatty liver disease (NAFLD). Uric acid (UA), a metabolite of fructose metabolism, may have a direct role in development of NAFLD, with unclear mechanism. This study aimed to evaluate role of fructose and UA in NAFLD and explore mechanisms of allopurinol (Allo, a UA lowering medication) on NAFLD in Otsuka Long-Evans Tokushima Fatty (OLETF) rats fed a high fructose diet (HFrD), with Long-Evans Tokushima Otsuka (LETO) rats used as a control. There were six groups: LETO, LETO-Allo, OLETF, OLETF-Allo, OLETF-HFrD, and OLETF-HFrD-Allo. HFrD significantly increased body weight, epididymal fat weight, and serum concentrations of UA, cholesterol, triglyceride, HbA1c, hepatic enzymes, HOMA-IR, fasting insulin, and two hour-glucose after intraperitoneal glucose tolerance tests, as well as NAFLD activity score of liver, compared to the OLETF group. Allopurinol treatment significantly reduced hepatic steatosis, epididymal fat, serum UA, HOMA-IR, hepatic enzyme levels, and cholesterol in the OLETF-HFrD-Allo group. Additionally, allopurinol significantly downregulated expression of lipogenic genes, upregulated lipid oxidation genes, downregulated hepatic pro-inflammatory cytokine genes, and decreased ER-stress induced protein expression, in comparison with the OLETF-HFrD group. In conclusion, allopurinol ameliorates HFrD-induced hepatic steatosis through modulation of hepatic lipid metabolism, inflammation, and ER stress pathway. UA may have a direct role in development of fructose-induced hepatic steatosis, and allopurinol could be a candidate for prevention or treatment of NAFLD.

Metabolic Spectrum of Liver Failure in Type 2 Diabetes and Obesity: From NAFLD to NASH to HCC

Liver disease is the spectrum of liver damage ranging from simple steatosis called as nonalcoholic fatty liver disease (NAFLD) to hepatocellular carcinoma (HCC). Clinically, NAFLD and type 2 diabetes coexist. Type 2 diabetes contributes to biological processes driving the severity of NAFLD, the primary cause for development of chronic liver diseases. In the last 20 years, the rate of non-viral NAFLD/NASH-derived HCC has been increasing rapidly. As there are currently no suitable drugs for treatment of NAFLD and NASH, a class of thiazolidinediones (TZDs) drugs for the treatment of type 2 diabetes is sometimes used to improve liver failure despite the risk of side effects. Therefore, diagnosis, prevention, and treatment of the development and progression of NAFLD and NASH are important issues. In this review, we will discuss the pathogenesis of NAFLD/NASH and NAFLD/NASH-derived HCC and the current promising pharmacological therapies of NAFLD/NASH. Further, we will provide insights into "adipose-derived adipokines" and "liver-derived hepatokines" as diagnostic and therapeutic targets from NAFLD to HCC.