Combination effects of alogliptin and pioglitazone on steatosis and hepatic fibrosis formation in a mouse model of non-alcoholic steatohepatitis

How far are we from an approved drug for non-alcoholic steatohepatitis?

INTRODUCTION

Metabolic associated fatty liver disease (MAFLD) previously known but still debatable, as non-alcoholic fatty liver disease (NAFLD) is one of the main causes of chronic liver disease and subsequent cirrhosis worldwide, accounting for around 30% of liver diseases. The change in its nomenclature has been brought about by the novel discoveries regarding its pathogenesis, in which metabolic dysfunction plays the most important role. It is widely known that for every disease, the treatment should always be targeted toward the underlying etiology and pathogenesis.

AREAS COVERED

MAFLD/NAFLD pathogenesis is heterogeneous, and includes multiple gene polymorphisms, presence of insulin resistance, as well as concomitant diseases that contribute to the disease onset and progression. As a result of this, even though lifestyle modification (owing to metabolic abnormalities) is the first line of treatment, multiple drugs have been tested to target each of the known pathways leading to MAFLD/NAFLD and progression of steatohepatitis. We aim to review the most relevant information regarding previous and ongoing research and recommendations regarding treatment of MAFLD/NAFLD.

EXPERT OPINION

Combination therapies associated to weight loss and exercise will be the optimal approach for these patients. It is important to evaluate each patient to select the specific combination according to patient characteristics.

Validation of a diet-induced Macaca fascicularis model of non-alcoholic steatohepatitis with dietary and pioglitazone interventions

AIM

To develop an obese, insulin-resistant cynomolgus monkey model of non-alcoholic steatohepatitis (NASH) with fibrosis with a high fat/high cholesterol (HFHC) diet (with or without high fructose) and test its responsiveness to caloric restriction or pioglitazone.

METHODS

First, two groups of monkeys (n = 24/group) with histologically proven NASH and fibrosis were fed the HFHC diet for 17 weeks. The treatment group was subjected to a 40% caloric restriction (CR) and had their diet switched from the HFHC diet to a chow diet (DSCR). Paired liver biopsies were taken before and 17 weeks after DSCR. Subsets of monkeys (nine/group) had whole liver fat content assessed by MRI. Next, two groups of monkeys with histologically proven NASH and fibrosis were treated with vehicle (n = 9) or pioglitazone (n = 20) over 24 weeks.

RESULTS

The HFHC and DSCR groups lost 0.9% and 11.4% of body weight, respectively. After 17 weeks, non-alcoholic fatty liver disease activity score (NAS) improvement was observed in 66.7% of the DSCR group versus 12.5% of the HFHC group (P < .001). Hepatic fat was reduced to 5.2% in the DSCR group versus 23.0% in the HFHC group (P = .0001). After 24 weeks, NAS improvement was seen in 30% of the pioglitazone group versus 0% of the vehicle group (P = .08).

CONCLUSIONS

Both weight loss induced by DSCR and treatment with pioglitazone improve the histological features of NASH in a diet-induced cynomolgus monkey model. This model provides a translational preclinical model for testing novel NASH therapies.

The effects of the voglibose on non-alcoholic fatty liver disease in mice model

The α-glucosidase inhibitor (α-GI) delays the intestinal absorption of glucose, which reduces postprandial hepatic glucose intake. This mechanism is considered to be effective in treating non-alcoholic fatty liver disease (NAFLD). Here, we investigated the effect of voglibose, an α-glucosidase inhibitor, on high-fat, high-fructose (HFHFr) diet-induced NAFLD models. Seven-week-old male C57BL/6J mice were randomly placed in a chow diet group or an HFHFr diet group. After 10 weeks, mice in the HFHFr group were randomly assigned to one of three groups: HFHFr diet with vehicle, HFHFr with voglibose, or HFHFr with pioglitazone. Each diet and treatment was continued for 10 weeks. The HFHFr diet induced severe NAFLD in terms of steatosis, hepatitis, and fibrosis. Administration of voglibose improved all aspects of NAFLD, comparable to those of pioglitazone, a positive control. In voglibose-treated mice, gene expressions of hepatic lipogenesis markers were significantly downregulated. In the in vitro experiment, reducing the influx of glucose into hepatocytes significantly reduced steatosis and de novo lipogenesis even in the presence of sufficient fructose and fat, demonstrating that the mechanism of voglibose could be effective in treating HFHFr diet-induced NAFLD. These results indicate that voglibose improves HFHFr diet-induced NAFLD by suppressing hepatic de novo lipogenesis.