Short-Term SGLT2 Inhibitor Administration Does Not Alter Systemic Insulin Clearance in Type 2 Diabetes

Rationale and Design of the Study to Investigate the Metabolic Action of Imeglimin on Patients with Type 2 Diabetes Mellitus (SISIMAI)

INTRODUCTION

Imeglimin is a first-in-class, novel, oral glucose-lowering agent for the treatment of type 2 diabetes mellitus. The efficacy and safety of imeglimin as an antidiabetic agent have been investigated in clinical trials. However, its metabolic effects in humans have not yet been fully elucidated.

METHODS

The Study to InveStIgate the Metabolic Action of Imeglimin on patients with type 2 diabetes mellitus (SISIMAI) is a single-arm intervention study. In this study, we have recruited 25 patients with type 2 diabetes to receive 2000 mg/day imeglimin for 20 weeks. We perform a 75-g oral glucose tolerance test (OGTT) with double-glucose tracers, a two-step hyperinsulinemic-euglycemic clamp with glucose tracer, ectopic fat measurement by proton magnetic resonance spectroscopy, visceral/subcutaneous fat area measurement by magnetic resonance imaging, muscle biopsy, and evaluation of fitness level by cycle ergometer before and after imeglimin administration.

PLANNED OUTCOMES

The primary outcome is the change in area under the curve of glucose levels during the OGTT after 20 weeks of imeglimin treatment. We also calculate the endogenous glucose production, rate of oral glucose appearance, and rate of glucose disappearance from the data during the 75-g OGTT and compare them between pre- and post-treatment. Additionally, we will compare other parameters, such as the changes in tissue-specific insulin sensitivity, ectopic fat accumulation, visceral/subcutaneous fat area accumulation, and fitness level between each point. This is the first study to investigate the organ-specific metabolic action of imeglimin in patients with type 2 diabetes mellitus using the 75-g OGTT with the double tracer method. The results of this study are expected to provide useful information for drug selection based on the pathophysiology of individual patients with type 2 diabetes mellitus.

TRIAL REGISTRATION

jRCTs031210600.

Four weeks SGLT2 inhibition improves beta cell function and glucose tolerance without affecting muscle free fatty acid or glucose uptake in subjects with type 2 diabetes

AIMS

Sodium glucose co-transporter-2 (SGLT2) inhibition lowers glucose levels independently of insulin, leading to reduced insulin secretion and increased lipolysis, resulting in elevated circulating free fatty acids (FFAs). While SGLT2 inhibition improves tissue insulin sensitivity, the increase in circulating FFAs could reduce insulin sensitivity in skeletal muscle and the liver. We aimed to investigate the effects of SGLT2 inhibition on substrate utilization in skeletal muscle and the liver and to measure beta-cell function and glucose tolerance.

METHODS

Thirteen metformin-treated individuals with type 2 diabetes were randomized to once-daily empagliflozin 25 mg or placebo for 4 weeks in a crossover design. Skeletal muscle glucose and FFA uptake together with hepatic tissue FFA uptake were measured using [18F]FDG positron emission tomography/computed tomography (PET/CT) and [11C]palmitate PET/CT. Insulin secretion and action were estimated using the oral minimal model.

RESULTS

Empagliflozin did not affect glucose (0.73 ± 0.30 vs. 1.16 ± 0.64, μmol/g/min p = 0.11) or FFA (0.60 ± 0.30 vs. 0.56 ± 0.3, μmol/g/min p = 0.54) uptake in skeletal muscle. FFA uptake in the liver (21.2 ± 10.1 vs. 19 ± 8.8, μmol/100 ml/min p = 0.32) was unaffected. Empagliflozin increased total beta-cell responsivity (20 ± 8 vs. 14 ± 9, 10-9 min-1, p < 0.01) and glucose effectiveness (2.6 × 10-2 ± 0.3 × 10-2 vs. 2.4 × 10-2 ± 0.3 × 10-2, dL/kg/min, p = 0.02).

CONCLUSIONS

Despite improved beta-cell function and glucose tolerance, empagliflozin does not appear to affect skeletal muscle FFA or glucose uptake.

The sodium-glucose cotransporter 2 inhibitor ipragliflozin improves liver function and insulin resistance in Japanese patients with type 2 diabetes

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment is a therapeutic approach for type 2 diabetes mellitus (T2DM). Some reports have shown that SGLT2i treatment improves insulin resistance; however, few studies have evaluated insulin resistance by the glucose clamp method. Hepatic insulin clearance (HIC) is a new pathophysiological mechanism of T2DM. The effect of SGLT2i treatment on hepatic insulin clearance and insulin resistance is not well known. We investigated the effect of SGLT2i treatment on insulin resistance, insulin secretion, incretin levels, body composition, and hepatic insulin clearance. We conducted a meal tolerance test (MTT) and a hyperinsulinemic-euglycemic clamp test in 9 T2DM patients. Ipragliflozin (50 mg/day) was administered, and the MTT and clamp test were performed after 4 months. We calculated HIC as the postprandial C-peptide AUC-to-insulin AUC ratio. We also measured GLP-1, GIP, and glucagon levels during the MTT. Body weight and HbA1c were decreased, although not significantly, after 4 months of treatment. Postprandial glucose, fasting insulin and postprandial insulin were significantly decreased. Insulin resistance with the glucose clamp was not changed, but the HOMA-IR and insulin sensitivity indices were significantly improved. Incretin and glucagon levels were not changed. Hepatic insulin clearance was significantly increased, but whole-body insulin clearance was not changed. The FIB-4 index and fatty liver index were significantly reduced. The HOMA-beta and insulinogenic indices were not changed, but the C-peptide index was significantly increased. Although the number of patients was small, these results suggested that SGLT2i treatment improved liver function, decreased hepatic insulin resistance, and increased hepatic insulin clearance, despite the small weight reduction.