Non-Alcoholic Fatty Liver Disease Treatment in Patients with Type 2 Diabetes Mellitus; New Kids on the Block

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD), affecting over 25% of the general population worldwide, is characterized by a spectrum of clinical and histological manifestations ranging from simple steatosis (>5% hepatic fat accumulation without inflammation) to non-alcoholic steatohepatitis (NASH) which is characterized by inflammation, and finally fibrosis, often leading to liver cirrhosis, and hepatocellular carcinoma. Up to 70% of patients with type 2 diabetes mellitus (T2DM) have NAFLD, and diabetics have much higher rates of NASH compared with the general non-diabetic population. Objective: The aim of this study is to report recent approaches to NAFLD/NASH treatment in T2DM patients. To-date, there are no approved treatments for NAFLD (apart from lifestyle measures). Results: Current guidelines (2016) from 3 major scientific organizations suggest that pioglitazone and vitamin E may be useful in a subset of patients for adult NAFLD/NASH patients with T2DM. Newer selective PPAR-γ modulators (SPPARMs, CHRS 131) have shown to provide even better results with fewer side effects in both animal and human studies in T2DM. Newer antidiabetic drugs might also be useful, but detailed studies with histological outcomes are largely lacking. Nevertheless, prior animal and human studies on incretin mimetics, glucagon-like peptide-1 receptor agonists (GLP-1 RA) approved for T2DM treatment, have provided indirect evidence that they may also ameliorate NAFLD/NASH, whereas dipeptidyl dipeptidase-4 inhibitors (DDP-4i) were not better than placebo in reducing liver fat in T2DM patients with NAFLD. Sodium-glucoseco-transporter-2 inhibitors (SGLT2i) have been reported to improve NAFLD/NASH. Statins, being necessary for most patients with T2DM, may also ameliorate NAFLD/NASH, and could potentially reinforce the beneficial effects of the newer antidiabetic drugs, if used in combination, but this remains to be identified. Conclusion: Newer antidiabetic drugs (SPPARMs, GLP-1 RA and SGLT2i) alone or in combination and acting alone or with potent statin therapy which is recommended in T2DM, might contribute substantially to NAFLD/NASH amelioration, possibly reducing not only liver-specific but also cardiovascular morbidity. These observations warrant long term placebo-controlled randomized trials with appropriate power and outcomes, focusing on the general population and more specifically on T2DM with NAFLD/NASH. Certain statins may be useful for treating NAFLD/NASH, while they substantially reduce cardiovascular disease risk.