Metabolomic analysis of serum samples from a clinical study on ipragliflozin and metformin treatment in Japanese patients with type 2 diabetes: Exploring human metabolites associated with visceral fat reduction.

Study objective: The effects of the sodium-dependent glucose transporter-2 inhibitor ipragliflozin were compared with metformin in a previous study, which revealed that ipragliflozin reduced visceral fat content by 12%; however, the underlying mechanism was unclear. Therefore, this sub-analysis aimed to compare metabolomic changes associated with ipragliflozin and metformin that may contribute to their biological effects.

Design: A sub-analysis of a randomized controlled study.

Setting: Chiba University Hospital and ten hospitals in Japan.

Patients: Fifteen patients with type 2 diabetes in the ipragliflozin group and 15 patients with type 2 diabetes in the metformin group with matching characteristics, such as age, sex, baseline A1C, baseline visceral fat area, smoking status, and concomitant medication.

Interventions: Ipragliflozin 50 mg or metformin 1000 mg daily.

Measurements: The clinical data were reanalyzed, and metabolomic analysis of serum samples collected before and 24 weeks after drug administration was performed using capillary electrophoresis time-of-flight mass spectrometry.

Main results: The reduction in the mean visceral fat area after 24 weeks of treatment was significantly larger (p = 0.002) in the ipragliflozin group (-19.8%) than in the metformin group (-2.5%), as were the subcutaneous fat area and body weight. The A1C and blood glucose levels decreased in both groups. Glutamic pyruvic oxaloacetic transaminase, γ-glutamyl transferase, uric acid, and triglyceride levels decreased in the ipragliflozin group. Low-density lipoprotein cholesterol levels decreased in the metformin group. After ipragliflozin administration, N2-phenylacetylglutamine, inosine, guanosine, and 1-methyladenosine levels increased, whereas galactosamine, glucosamine, 11-aminoundecanoic acid, morpholine, and choline levels decreased. After metformin administration, metformin, hypotaurine, methionine, methyl-2-oxovaleric acid, 3-nitrotyrosine, and cyclohexylamine levels increased, whereas citrulline, octanoic acid, indole-3-acetaldehyde, and hexanoic acid levels decreased.

Conclusions: Metabolites that may affect visceral fat reduction were detected in the ipragliflozin group. Studies are required to further elucidate the underlying mechanisms.