Dipeptidyl peptidase 4 inhibitor improves insulin resistance in Japanese patients with type 2 diabetes: a single-arm study, a brief report

Impact of Dipeptidyl Peptidase-4 Inhibitors on Aminotransferases Levels in Patients with Type 2 Diabetes Mellitus With Nonalcoholic Fatty Liver Disease: A Meta-Analysis of Randomized Controlled Trial

Background

Type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD) are highly prevalent diseases that constitute enormous public health problems. The efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors in blood glucose control in T2DM patients with NAFLD has been established, but little is known about its effect on liver enzyme levels.

Objective

This meta-analysis aimed to evaluate the influences of DPP-4 inhibitors on alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in patients with T2DM and NAFLD.

Methods

To identify the relevant studies, we searched PubMed, Embase, the Cochrane Library, Wanfang Data, and China National Knowledge Infrastructure. Means differences in liver enzymes and metabolic outcomes were meta-analyzed using a random-effects model, with subgroup analyses by gender, age, area, follow-up duration, and type of DPP-4 inhibitor. Quality assessment of the included studies was conducted using the revised Cochrane risk of bias tool.

Results

A total of 1323 patients from 16 studies were included in this meta-analysis. The results of analysis of DPP-4 inhibitors showed that the mean difference was -6.19 (95% confidence interval [CI]: -9.45 to -2.92) for ALT and -5.17 (95% CI: -8.10 to -2.23) for AST; this effect was statistically significant from the placebo group which indicates the beneficial effect on liver enzymes. Subgroup analysis revealed that while there were no significant gender differences in enzyme reductions, individuals over 55 years old experienced more pronounced decreases in ALT. Notably, Asian studies showed significant reductions in liver enzymes, contrasting with the minor variations observed in Euramerican regions, and the effectiveness of DPP-4 inhibitors was particularly pronounced during shorter follow-up periods, with effects diminishing over time. Regarding secondary outcomes, there was a notable improvement in gamma-glutamyl transpeptidase, with a mean reduction, and in HbA1c levels, indicating improved glycemic control. Homeostatic model assessment for insulin resistance levels also improved, reflecting better insulin sensitivity. Additionally, adverse event analysis confirmed that DPP-4 inhibitors were well-tolerated with a favorable safety profile.

Conclusions

DPP-4 inhibitors appear to enhance glycemic control and improve liver enzyme levels, suggesting a potentially effective therapeutic approach for managing T2DM/NAFLD and highlighting their broader metabolic benefits.

Effect of Teneligliptin 20 mg Twice Daily on Glucagon-Like Peptide-1 Levels and Its Influence on Non-Glycemic Components in Non-Diabetic Obese Individuals

Background and Aims: Teneligliptin is an oral antidiabetic agent, it can persevere glucagon-like peptide-1 (GLP-1) by inhibiting dipeptidyl peptidase enzyme. In addition, it has rare incidence of hypoglycemia. Hence, this study aimed to test the effect of teneligliptin 20 mg twice daily along with low carbohydrate diet and physical exercise on change of body weight and insulin resistance in nondiabetic obese subjects. Materials and Methods: It is a prospective, randomized, double-blind, placebo-controlled, parallel group study carried out at outpatient department of an endocrinology hospital over the period of 48 weeks. Teneligliptin 20 mg twice daily 30 min before food (low carbohydrate diet [LCD]) with regular physical exercise, and control group was kept with placebo twice daily 30 min before food LCD with regular physical exercise. This study was registered in clinical trial registry of India [CTRI/2020/02/023329]. Results: A total of 150 nondiabetic obese subjects were randomized into test (n = 75) and control groups (n = 75). At the end of 48 weeks there was significant improvement in GLP-1, simplified nutrition assessment questionnaire (SNAQ) score, homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides (TG), and body weight. The mean difference and 95% confidence interval of GLP-1 (pg/mL) was 76.42 (44.42-148.41) (P = 0.37); SNAQ score, -1.64 (-2.48 to -0.81) (P = 0.000); HOMA-IR, -0.9 (-0.59 to -0.38) (P = 0.000); TG (mg/dL) -29.37 (-44.46 to -14.07) (P = 0.000); reduction of body weight (kilograms) -3.09 (-6.11 to -0.07) (P = 0.043). Conclusion: Findings of this study reveals that teneligliptin-treated group showed significant improvement in GLP-1 levels, reduced insulin resistance, body weight, TG, appetite, and metabolic syndrome. Teneligliptin is well tolerated, except in upper respiratory tract infections. CTR number: CTRI/2020/02/023329.

A Descriptive Review of the Action Mechanisms of Berberine, Quercetin and Silymarin on Insulin Resistance/Hyperinsulinemia and Cardiovascular Prevention

Insulin resistance (IR) and the associated hyperinsulinemia are early pathophysiological changes which, if not well treated, can lead to type 2 diabetes, endothelial dysfunction and cardiovascular disease. While diabetes care is fairly well standardized, the prevention and treatment of IR lacks a single pharmaceutical approach and many lifestyle and dietary interventions have been proposed, including a wide range of food supplements. Among the most interesting and well-known natural remedies, alkaloid berberine and the flavonol quercetin have particular relevance in the literature, while silymarin-the active principle of the Silybum marianum thistle-was traditionally used for lipid metabolism disorders and to sustain liver function. This review describes the major defects of insulin signaling leading to IR and the main properties of the three mentioned natural substances, their molecular targets and synergistic action mechanisms. The actions of berberine, quercetin and silymarin are partially superimposable as remedies against reactive oxygen intermediates generated by a high-lipid diet and by NADPH oxidase, which is triggered by phagocyte activation. Furthermore, these compounds inhibit the secretion of a battery of pro-inflammatory cytokines, modulate intestinal microbiota and are especially able to control the various disorders of the insulin receptor and post-receptor signaling systems. Although most of the evidence on the effects of berberine, quercetin and silymarin in modulating insulin resistance and preventing cardiovascular disease derive from experimental studies on animals, the amount of pre-clinical knowledge strongly suggests the need to investigate the therapeutic potential of these substances in human pathology.