Fat and Fibrosis: Does Empagliflozin Impair the Progression of Nonalcoholic Steatohepatitis in Patients with Type 2 Diabetes Mellitus?

Altered lipid metabolism and the development of metabolic-associated fatty liver disease

PURPOSE OF REVIEW

An increasing amount of research has underscored the significant role of lipoproteins in the pathogenesis of metabolic-associated fatty liver disease (MAFLD). This comprehensive review examines the intricate relationship between lipoprotein abnormalities and the development of MAFLD.

RECENT FINDINGS

Atherogenic dyslipidemia seen in insulin resistance states play a significant role in initiating and exacerbating hepatic lipid accumulation. There are also specific genetic factors ( PNPLA3 , TM6SF2 , MBOAT7 , HSD17B13 , GCKR- P446L) and transcription factors (SREBP-2, FXR, and LXR9) that increase susceptibility to both lipoprotein disorders and MAFLD. Most monogenic primary lipid disorders do not cause hepatic steatosis unless accompanied by metabolic stress. Hepatic steatosis occurs in the presence of secondary systemic metabolic stress in conjunction with predisposing environmental factors that lead to insulin resistance. Identifying specific aberrant lipoprotein metabolic factors promoting hepatic fat accumulation and subsequently exacerbating steatohepatitis will shed light on potential targets for therapeutic interventions.

SUMMARY

The clinical implications of interconnection between genetic factors and an insulin resistant environment that predisposes MAFLD is many fold. Potential therapeutic strategies in preventing or mitigating MAFLD progression include lifestyle modifications, pharmacological interventions, and emerging therapies targeting aberrant lipoprotein metabolism.

Nonalcoholic fatty liver disease (NAFLD) from pathogenesis to treatment concepts in humans

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) comprises hepatic alterations with increased lipid accumulation (steatosis) without or with inflammation (nonalcoholic steatohepatitis, NASH) and/or fibrosis in the absence of other causes of liver disease. NAFLD is developing as a burgeoning health challenge, mainly due to the worldwide obesity and diabetes epidemics.

SCOPE OF REVIEW

This review summarizes the knowledge on the pathogenesis underlying NAFLD by focusing on studies in humans and on hypercaloric nutrition, including effects of saturated fat and fructose, as well as adipose tissue dysfunction, leading to hepatic lipotoxicity, abnormal mitochondrial function, and oxidative stress, and highlights intestinal dysbiosis. These mechanisms are discussed in the context of current treatments targeting metabolic pathways and the results of related clinical trials.

MAJOR CONCLUSIONS

Recent studies have provided evidence that certain conditions, for example, the severe insulin-resistant diabetes (SIRD) subgroup (cluster) and the presence of an increasing number of gene variants, seem to predispose for excessive risk of NAFLD and its accelerated progression. Recent clinical trials have been frequently unsuccessful in halting or preventing NAFLD progression, perhaps partly due to including unselected cohorts in later stages of NAFLD. On the basis of this literature review, this study proposed screening in individuals with the highest genetic or acquired risk of disease progression, for example, the SIRD subgroup, and developing treatment concepts targeting the earliest pathophysiolgical alterations, namely, adipocyte dysfunction and insulin resistance.

Empagliflozin Improves Liver Steatosis and Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease and Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

INTRODUCTION

To evaluate the efficacy of empagliflozin compared to pioglitazone in patients with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2DM).

METHODS

In this prospective randomized, double-blind, placebo-controlled trial, we assigned 106 patients with NAFLD and T2DM to receive empagliflozin 10 mg (n = 35), pioglitazone 30 mg (n = 34), or placebo (n = 37) for 24 weeks. Liver fat content and liver stiffness were measured using fibroscans. Body composition assessment was performed by dual-energy x-ray absorptiometry (DEXA) scans. The primary end point was change from baseline in liver steatosis, using the controlled attenuation parameter (CAP) score.

RESULTS

A borderline significant decrease in CAP score was observed with empagliflozin compared to placebo, mean difference: - 29.6 dB/m (- 39.5 to - 19.6) versus - 16.4 dB/m (- 25.0 to - 7.8), respectively; p = 0.05. Using multivariate analysis, we observed a significant reduction in the placebo-corrected change in liver stiffness measurement (LSM) with empagliflozin compared to pioglitazone: - 0.77 kPa (- 1.45, - 0.09), p  = 0.02, versus 0.01 kPa (95% CI - 0.70, 0.71, p  = 0.98), p for comparison = 0.03. Changes in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), fasting insulin, homeostatic model assessment for insulin resistance (HOMA-IR), HOMA2-IR, fibrosis-4 index (FIB4 index), NAFLD fibrosis score, aspartate aminotransferase to platelet ratio index (APRI), android/gynecoid ratio (A/G ratio), and skeletal muscle index (SMI) were comparable between the two treatment groups, while significant reductions of the body weight and visceral fat area were observed only in the empagliflozin group (p  < 0.001 and p  = 0.01, respectively) and both were increased in the placebo and pioglitazone groups. There were no serious adverse events in either group.

CONCLUSION

Treatment for 24 weeks with empagliflozin, in contrast to pioglitazone, was associated with improvement of liver steatosis and fibrosis in patients with NAFLD and T2DM. In addition, body weight and abdominal fat area were decreased in the empagliflozin group.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT), IRCT20190122042450N3.

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.