Glycaemic control efficacy of switching from dipeptidyl peptidase-4 inhibitors to oral semaglutide in subjects with type 2 diabetes: A multicentre, prospective, randomized, open-label, parallel-group comparison study (SWITCH-SEMA 2 study).

AIM: To assess whether oral semaglutide provides better glycaemic control, compared with dipeptidyl peptidase-4 inhibitor (DPP-4i) continuation, in people with type 2 diabetes. MATERIALS AND METHODS: In this multicentre, open-label, prospective, randomized, parallel-group comparison study, participants receiving DPP-4is were either switched to oral semaglutide (3-14 mg/day) or continued on DPP-4is. The primary endpoint was the change in glycated haemoglobin (HbA1c) over 24 weeks. Secondary endpoints included changes in metabolic parameters and biomarkers, along with the occurrence of adverse events. Factors associated with HbA1c improvement were also explored. RESULTS: In total, 174 eligible participants were enrolled; 17 dropped out of the study. Consequently, 82 participants in the DPP-4i group and 75 participants in the semaglutide group completed the study and were included in the analysis. Improvement in HbA1c at week 24 was significantly greater when switching to semaglutide compared with DPP-4i continuation [-0.65 (95% confidence interval: -0.79, -0.51) vs. +0.05 (95% confidence interval: -0.07, 0.16) (p < .001)]. Body weight, lipid profiles and liver enzymes were significantly improved in the semaglutide group than in the DPP-4i continuation group. Multiple linear regression analysis revealed that baseline HbA1c and homeostasis model assessment 2-R were independently associated with HbA1c improvement after switching to semaglutide. Seven participants in the semaglutide group discontinued medication because of gastrointestinal symptoms. CONCLUSIONS: Although the potential for gastrointestinal symptoms should be carefully considered, switching from DPP-4is to oral semaglutide may be beneficial for glycaemic control and metabolic abnormalities in people with higher HbA1c and insulin resistance.

Improvement of glycaemic control and treatment satisfaction by switching from liraglutide or dulaglutide to subcutaneous semaglutide in patients with type 2 diabetes: A multicentre, prospective, randomized, open-label, parallel-group comparison study (SWITCH-SEMA 1 study).

AIM: To investigate the effects of switching from liraglutide or dulaglutide to once-weekly semaglutide on glycaemic control and treatment satisfaction in patients with type 2 diabetes. MATERIALS AND METHODS: In this multicentre, open-labelled, prospective, randomized, parallel-group comparison study, patients treated with liraglutide 0.9-1.8 mg/day (plan A) or dulaglutide 0.75 mg/week (plan B) were either switched to semaglutide or continued current therapy. The primary endpoint was the mean change in glycated haemoglobin over 24 weeks. The secondary endpoints included the changes of Diabetes Treatment Satisfaction Questionnaire scores, body weight and metabolic indices. RESULTS: In total, 110 patients were enrolled, and 10 were excluded; therefore, 37 patients in plan A and 63 patients in plan B completed the study. Glycated haemoglobin levels were significantly reduced in the semaglutide group in both plans [plan A, 7.8% ± 1.0% to 7.8% ± 0.7% (liraglutide) vs. 7.9% ± 0.7% to 7.3% ± 0.7% (semaglutide), p < .01; plan B, 7.8% ± 1.0% to 7.9% ± 1.2% (dulaglutide) vs. 7.8% ± 0.8% to 7.1% ± 0.6% (semaglutide), p < .01]. Semaglutide also improved Diabetes Treatment Satisfaction Questionnaire scores in both groups (plan A, +0.1 vs. +8.3, p < .01; plan B, -1.2 vs. +3.5, p < .01). Switching from dulaglutide yielded greater reductions in body weight and improved metabolic parameters. CONCLUSIONS: Once-weekly semaglutide administration improved glycaemic control and treatment satisfaction after switching from liraglutide or dulaglutide. These results highlighted a useful treatment option for patients with metabolic abnormalities despite glucagon-like receptor-1 receptor agonist treatment.

Direct visualization of glucagon-like peptide-1 secretion by fluorescent fusion proteins.

Live-cell imaging with fluorescent proteins (FPs) is a powerful tool for investigating the exocytosis processes of hormones. However, the secretion process of glucagon-like peptide-1 (GLP-1) has not been visualized by FPs, which might be because tagging FPs inhibits GLP-1 synthesis through the post-translational processing from proglucagon. Here, we have developed FP-tagged GLP-1 by inserting FPs into the middle of GLP-1 and adding the proglucagon signal peptide. Confocal imaging confirmed that GLP-1 fused to FPs with high folding efficiency showed granular structure, in which secretory vesicle markers colocalized. The fluorescence intensity of FP in the culture supernatant from cells treated with KCl or forskolin was significantly increased compared with those from untreated cells. Furthermore, FP-tagged GLP-1 enables direct visualization of stimulation-dependent exocytosis of GLP-1 at a single granule resolution with total internal reflection fluorescence microscopy. FP-tagged GLP-1 might facilitate the screening of GLP-1 secretagogues and the discovery of new antidiabetic drugs.

Folding Latency of Fluorescent Proteins Affects the Mitochondrial Localization of Fusion Proteins.

The discovery of fluorescent proteins (FPs) has revolutionized cell biology. The fusion of targeting sequences to FPs enables the investigation of cellular organelles and their dynamics; however, occasionally, such fluorescent fusion proteins (FFPs) exhibit behavior different from that of the native proteins. Here, we constructed a color pallet comprising different organelle markers and found that FFPs targeted to the mitochondria were mislocalized when fused to certain types of FPs. Such FPs included several variants of Aequorea victoria green FP (avGFP) and a monomeric variant of the red FP. Because the FFPs that are mislocalized include FPs with faster maturing or folding mutations, the increase in the maturation rate is likely to prevent their expected localization. Indeed, when we reintroduced amino acid substitutions so that the FP sequences were equivalent to that of wild-type avGFP, FFP localization to the mitochondria was significantly enhanced. Moreover, similar amino acid substitutions improved the localization of mitochondria-targeted pHluorin, which is a pH-sensitive variant of GFP, and its capability to monitor pH changes in the mitochondrial matrix. Our findings demonstrate the importance of selecting FPs that maximize FFP function.Key words: fluorescent protein, organelle, fusion protein, mitochondria.