Effect of canagliflozin treatment on hepatic triglyceride content and glucose metabolism in patients with type 2 diabetes

Non-Alcoholic Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus: A Position Statement of the Fatty Liver Research Group of the Korean Diabetes Association

This clinical practice position statement, a product of the Fatty Liver Research Group of the Korean Diabetes Association, proposes recommendations for the diagnosis, progression and/or severity assessment, management, and follow-up of non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM). Patients with both T2DM and NAFLD have an increased risk of non-alcoholic steatohepatitis (NASH) and fibrosis and a higher risk of cardiovascular diseases and diabetic complications compared to those without NAFLD. With regards to the evaluation of patients with T2DM and NAFLD, ultrasonography-based stepwise approaches using noninvasive biomarker models such as fibrosis-4 or the NAFLD fibrosis score as well as imaging studies such as vibration-controlled transient elastography with controlled attenuation parameter or magnetic resonance imaging-proton density fat fraction are recommended. After the diagnosis of NAFLD, the stage of fibrosis needs to be assessed appropriately. For management, weight reduction achieved by lifestyle modification has proven beneficial and is recommended in combination with antidiabetic agent(s). Evidence that some antidiabetic agents improve NAFLD/NASH with fibrosis in patients with T2DM is emerging. However, there are currently no definite pharmacologic treatments for NAFLD in patients with T2DM. For specific cases, bariatric surgery may be an option if indicated.

A diabetologist's perspective of non-alcoholic steatohepatitis (NASH): Knowledge gaps and future directions

There is a close link between steatohepatitis (NASH) and Type 2 diabetes (T2DM). Recently, the American Diabetes Association (ADA) recommended screening for NASH and advanced fibrosis in patients with diabetes and hepatic steatosis or elevated plasma alanine aminotransferase (ALT). This is because as many as ~30% to 40% may have NASH and ~10% to 15% advanced fibrosis. The role of hyperglycemia and the natural history of NASH in diabetes remain poorly understood, as well as which diagnostic algorithm or interventions are most cost-effective. There is significant clinical inertia and most patients today are still not receiving adequate lifestyle intervention or pharmacological treatment with diabetes agents known to be effective against NASH. Lifestyle intervention improves steatohepatitis in proportion to the magnitude of weight loss, but this trend is not as consistent for regression of fibrosis. This limited success supports the need for concomitant pharmacological therapy. Pioglitazone has been shown to consistently induce resolution of NASH in both patients with or without diabetes in a total of 498 participants in five randomized controlled trials (RCTs), but with modest effects on liver fibrosis. Proof-of-concept studies suggest a potential role for GLP-1RAs and SGLT2 inhibitors. Combination therapy is on the horizon. Treating diabetes and NASH with a combination of pioglitazone, GLP-1RAs or SGLT2i, could be a cost-effective strategy to treat both diseases while reducing their high cardiovascular risk. Future combination therapies will likely combine existing diabetes agents with novel NASH-spechfic drugs under development. This review highlights current knowledge gaps and proposes future directions for the treatment of NASH in diabetes.

Empagliflozin Effectively Lowers Liver Fat Content in Well-Controlled Type 2 Diabetes: A Randomized, Double-Blind, Phase 4, Placebo-Controlled Trial

OBJECTIVE

To evaluate whether the sodium-glucose cotransporter 2 inhibitor empagliflozin (EMPA) reduces liver fat content (LFC) in recent-onset and metabolically well-controlled type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Patients with T2D (n = 84) (HbA_1c 6.6 ± 0.5% [49 ± 10 mmol/mol], known disease duration 39 ± 27 months) were randomly assigned to 24 weeks of treatment with 25 mg daily EMPA or placebo. The primary end point was the difference of the change in LFC as measured with magnetic resonance methods from 0 (baseline) to 24 weeks between groups. Tissue-specific insulin sensitivity (secondary outcome) was assessed by two-step clamps using an isotope dilution technique. Exploratory analysis comprised circulating surrogate markers of insulin sensitivity and liver function. Statistical comparison was done by ANCOVA adjusted for respective baseline values, age, sex, and BMI.

RESULTS

EMPA treatment resulted in a placebo-corrected absolute change of -1.8% (95% CI -3.4, -0.2; P = 0.02) and relative change in LFC of -22% (-36, -7; P = 0.009) from baseline to end of treatment, corresponding to a 2.3-fold greater reduction. Weight loss occurred only with EMPA (placebo-corrected change -2.5 kg [-3.7, -1.4]; P < 0.001), while no placebo-corrected change in tissue-specific insulin sensitivity was observed. EMPA treatment also led to placebo-corrected changes in uric acid (-74 mol/L [-108, -42]; P < 0.001) and high-molecular-weight adiponectin (36% [16, 60]; P < 0.001) levels from 0 to 24 weeks.

CONCLUSIONS

EMPA effectively reduces hepatic fat in patients with T2D with excellent glycemic control and short known disease duration. Interestingly, EMPA also decreases circulating uric acid and raises adiponectin levels despite unchanged insulin sensitivity. EMPA could therefore contribute to the early treatment of nonalcoholic fatty liver disease in T2D.

How Do SGLT2 (Sodium-Glucose Cotransporter 2) Inhibitors and GLP-1 (Glucagon-Like Peptide-1) Receptor Agonists Reduce Cardiovascular Outcomes?: Completed and Ongoing Mechanistic Trials

OBJECTIVE

There is substantial interest in how GLP-1RA (glucagon-like peptide-1 receptor agonists) and SGLT2 (sodium-glucose cotransporter 2) inhibitors reduce cardiovascular and renal events; yet, robust mechanistic data in humans remain sparse. We conducted a narrative review of published and ongoing mechanistic clinical trials investigating the actions of SGLT2 inhibitors and GLP-1RAs to help the community appreciate the extent of ongoing work and the variety and design of such trials. Approach and Results: To date, trials investigating the mechanisms of action of SGLT2 inhibitors have focused on pathways linked to glucose metabolism and toxicity, hemodynamic/volume, vascular and renal actions, and cardiac effects, including those on myocardial energetics. The participants studied have included those with established cardiovascular disease (including coronary artery disease and heart failure), liver disease, renal impairment, obesity, and hypertension; some of these trials have enrolled patients both with and without type 2 diabetes mellitus. GLP-1RA mechanistic trials have focused on glucose-lowering, insulin-sparing, weight reduction, and blood pressure-lowering effects, as well as possible direct vascular, cardiac, and renal effects of these agents. Very few mechanisms of action of SGLT2 inhibitors or GLP-1RAs have so far been convincingly demonstrated. One small trial (n=97) of SGLT2 inhibitors has investigated the cardiac effects of these drugs, where a small reduction in left ventricular mass was found. Data on vascular effects are limited to one trial in type 1 diabetes mellitus, which suggests some beneficial actions. SGLT2 inhibitors have been shown to reduce liver fat. We highlight the near absence of mechanistic data to explain the beneficial effects of SGLT2 inhibitors in patients without diabetes mellitus. GLP-1RAs have not been found to have major cardiovascular mechanisms of action in the limited, completed trials. Conflicting data around the impact on infarct size have been reported. No effect on left ventricular ejection fraction has been demonstrated.

CONCLUSIONS

We have tabulated the extensive ongoing mechanistic trials that will report over the coming years. We report 2 exemplar ongoing mechanistic trials in detail to give examples of the designs and techniques employed. The results of these many ongoing trials should help us understand how SGLT2 inhibitors and GLP-1RAs improve cardiovascular and renal outcomes and may also identify unexpected mechanisms suggesting novel therapeutic applications.

Nonalcoholic Fatty Liver Disease in Adults: Current Concepts in Etiology, Outcomes, and Management

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of disease, extending from simple steatosis to inflammation and fibrosis with a significant risk for the development of cirrhosis. It is highly prevalent and is associated with significant adverse outcomes both through liver-specific morbidity and mortality but, perhaps more important, through adverse cardiovascular and metabolic outcomes. It is closely associated with type 2 diabetes and obesity, and both of these conditions drive progressive disease toward the more advanced stages. The mechanisms that govern hepatic lipid accumulation and the predisposition to inflammation and fibrosis are still not fully understood but reflect a complex interplay between metabolic target tissues including adipose and skeletal muscle, and immune and inflammatory cells. The ability to make an accurate assessment of disease stage (that relates to clinical outcome) can also be challenging. While liver biopsy is still regarded as the gold-standard investigative tool, there is an extensive literature on the search for novel noninvasive biomarkers and imaging modalities that aim to accurately reflect the stage of underlying disease. Finally, although no therapies are currently licensed for the treatment of NAFLD, there are interventions that appear to have proven efficacy in randomized controlled trials as well as an extensive emerging therapeutic landscape of new agents that target many of the fundamental pathophysiological processes that drive NAFLD. It is highly likely that over the next few years, new treatments with a specific license for the treatment of NAFLD will become available.

From NASH to diabetes and from diabetes to NASH: Mechanisms and treatment options

The worldwide prevalence of non-alcoholic fatty liver disease (NAFLD) is estimated to have reached 25% or more in adults. NAFLD is prevalent in obese individuals, but may also affect non-obese insulin-resistant individuals. NAFLD is associated with a 2- to 3-fold increased risk of developing type 2 diabetes (T2D), which may be higher in patients with more severe liver disease - fibrosis increases this risk. In NAFLD, not only the close association with obesity, but also the impairment of many metabolic pathways, including decreased hepatic insulin sensitivity and insulin secretion, increase the risk of developing T2D and related comorbidities. Conversely, patients with diabetes have a higher prevalence of steatohepatitis, liver fibrosis and end-stage liver disease. Genetics and mechanisms involving dysfunctional adipose tissue, lipotoxicity and glucotoxicity appear to play a role. In this review, we discuss the altered pathophysiological mechanisms that underlie the development of T2D in NAFLD and vice versa. Although there is no approved therapy for the treatment of NASH, we discuss pharmacological agents currently available to treat T2D that could potentially be useful for the management of NASH.

The Effects of Hypoglycemic Agents on Non-alcoholic Fatty Liver Disease: Focused on Sodium-Glucose Cotransporter 2 Inhibitors and Glucagon-Like Peptide-1 Receptor Agonists

The only known, effective intervention for non-alcoholic fatty liver disease (NAFLD) is weight loss, and there is no approved pharmacotherapy. Recently, new hypoglycemic agents, such as sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RAs), and their effects on NAFLD have received substantial interest. Herein, we review the currently available human studies regarding the effects of SGLT2 inhibitors and GLP-1RAs on NAFLD/non-alcoholic steatohepatitis in patients with type 2 diabetes mellitus, and we describe the possible mechanisms explaining the positive effects of these agents on NAFLD.