Improvement of ß-Cell Function After Switching From DPP-4 Inhibitors to Oral Semaglutide: SWITCH-SEMA2 Post Hoc Analysis.

CONTEXT: Whether continuation of dipeptidyl peptidase-4 inhibitors (DPP-4is) or switching to oral semaglutide is more beneficial for ß-cell function is unclear. OBJECTIVE: To assess the efficacy of switching from DPP-4is to oral semaglutide for ß-cell function compared with DPP-4i continuation. METHODS: Post hoc analysis of SWITCH-SEMA 2, a multicenter prospective randomized controlled trial on the switch to oral semaglutide vs DPP-4i continuation without dose adjustment for 24 weeks in subjects with type 2 diabetes treated with DPP-4is, was conducted. Changes in markers for glucose metabolism, including homeostatic model assessment (HOMA2) scores and disposition index (DI), were compared between the groups. RESULTS: A total of 146 subjects (semaglutide group, 69; DPP-4i group, 77) were analyzed. In the semaglutide group, glycemic control, liver enzyme deviations, and lipid profiles improved after 24 weeks. Regarding indices for ß-cell function, changes in HOMA2-ß as well as DI, reflecting the ability of ß-cells to compensate for insulin resistance, were significantly higher in the semaglutide group compared with the DPP-4i group (mean change, +10.4 vs +0.6 in HOMA2-ß [P = .001] and +0.09 vs 0.0 in DI [P < .001]). Improvement in DI in the semaglutide group was correlated significantly to changes in body mass index (BMI), HbA1c, and fatty liver index reflecting liver steatosis. Multiple linear regression analysis revealed that dose of semaglutide (≥ 7 mg/day), reduction in fatty liver index, and metformin nonuse were independently associated with improvement of DI. CONCLUSION: Switching to oral semaglutide ameliorated ß-cell function compared with DPP-4is, presumably via tissue-to-tissue crosstalk between liver and ß-cells.

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.

Luseogliflozin preserves the pancreatic beta-cell mass and function in db/db mice by improving mitochondrial function.

We aimed to determine the mechanism by which the sodium glucose co-transporter 2 inhibitor, luseogliflozin, preserves pancreatic beta-cell mass and function in db/db mice. Six-week-old db/db mice were fed to standard chow or standard chow containing 0.01% luseogliflozin. After 4 weeks, DNA microarray analysis, real-time PCR analysis, and measurement of mitochondrial respiratory capacity and reactive oxygen species (ROS) generation were performed using isolated islets. Immunohistochemistry and electron microscopic analysis were performed using pancreatic tissues. Metabolites extracted from the islets were measured by capillary electrophoresis mass spectrometry. The expression of genes involved in the tricarboxylic acid (TCA) cycle and electron transport chain was upregulated by luseogliflozin. Luseogliflozin improved the mitochondrial complex II-linked oxidative phosphorylation capacity and reduced ROS generation. Mitochondrial morphology was normally maintained by luseogliflozin. Luseogliflozin increased NK6 homeobox 1 (NKX6.1) expression and TCA cycle metabolites. Relief of glucotoxicity by luseogliflozin may involve lower mitochondrial ROS generation and an improvement in complex II-linked mitochondrial respiration. Reducing ROS generation through preventing complex II damage likely increases NKX6.1 expression and ameliorate glucose metabolism in the TCA cycle, contributing to the protection of pancreatic beta-cells. Protection of complex II in pancreatic beta-cells represents a novel therapeutic target for type 2 diabetes.

Glucokinase activation leads to an unsustained hypoglycaemic effect with hepatic triglyceride accumulation in db/db mice.

AIM: To investigate how subchronic administration of a glucokinase activator (GKA) results in attenuation of the hypoglycaemic effect in the diabetic condition. MATERIALS AND METHODS: Six-week-old db/db mice were fed standard chow containing a GKA or the sodium-glucose cotransporter 2 inhibitor ipragliflozin for 1, 6, 14 or 28 days. We performed histological evaluation and gene expression analysis of the pancreatic islets and liver after each treatment and compared the results to those in untreated mice. RESULTS: The unsustained hypoglycaemic effect of GKAs was reproduced in db/db mice in conjunction with significant hepatic fat accumulation. The initial reactions to treatment with the GKA in the liver were upregulation of the gene expression of carbohydrate response element-binding protein beta (Chrebp-b) and downregulation of phosphoenolpyruvate carboxykinase (Pepck) on day 1. Subsequently, the initial changes in Chrebp-b and Pepck disappeared and increases in the expression of genes involved in lipogenesis, including acetyl-CoA carboxylase and fatty acid synthase, were observed. There were no significant changes in the pancreatic ß cells nor in hepatic insulin signalling. CONCLUSIONS: The GKA showed an unsustained hypoglycaemic effect and promoted hepatic fat accumulation in db/db mice. Dynamic changes in the expression of hepatic genes involved in lipogenesis and gluconeogenesis could affect the unsustained hypoglycaemic effect of the GKA despite no changes in pancreatic ß-cell function and mass.

Dipeptidyl peptidase-4 inhibitor might exacerbate Graves' disease: A multicenter observational case-control study.

Dipeptidyl peptidase-4 (DPP-4), namely CD26, is expressed on the surface of immune cells, suggesting that inhibition of DPP-4 might affect the immune system. The current multicenter observational case-control study was carried out to investigate the effects of DPP-4 inhibitor (DPP-4i) administration on Graves' disease (GD) activity. This study comprised patients with GD and type 2 diabetes, who were administered an oral hypoglycemic agent including DPP-4i. Exacerbation of GD was defined as an increase of antithyroid drug dose by 6 months after oral hypoglycemic agent administration. A total of 80 patients were enrolled and divided into an exacerbation group or a non-exacerbation group. The frequency of DPP-4i administration was significantly higher in the exacerbation group (88%) than that in the non-exacerbation group (31%). In multivariate logistic regression analysis, there was a significant association between DPP-4i administration and GD exacerbation (odds ratio 7.39). The current study suggests that DPP-4i administration is associated with GD exacerbation.

Glucokinase is required for high-starch diet-induced ß-cell mass expansion in mice.

AIMS/INTRODUCTION: We aimed to determine whether glucokinase is required for ß-cell mass expansion induced by high-starch diet (HSTD)-feeding, as has been shown in its high-fat diet-induced expansion. MATERIALS AND METHODS: Eight-week-old male wild-type (Gck+/+ ) or glucokinase haploinsufficient (Gck+/- ) mice were fed either a normal chow (NC) or an HSTD for 15 weeks. The bodyweight, glucose tolerance, insulin sensitivity, insulin secretion and ß-cell mass were assessed. RESULTS: Both HSTD-fed Gck+/+ and Gck+/- mice had significantly higher bodyweight than NC-fed mice. Insulin and oral glucose tolerance tests revealed that HSTD feeding did not affect insulin sensitivity nor glucose tolerance in either the Gck+/+ or Gck+/- mice. However, during the oral glucose tolerance test, the 15-min plasma insulin concentration after glucose loading was significantly higher in the HSTD group than that in the NC group for Gck+/+ , but not for Gck+/- mice. ß-Cell mass was significantly larger in HSTD-fed Gck+/+ mice than that in NC-fed Gck+/+ mice. In contrast, the ß-cell mass of the HSTD-fed Gck+/- mice was not different from that of the NC-fed Gck+/- mice. CONCLUSIONS: The results showed that HSTD feeding would increase pancreatic ß-cell mass and insulin secretion in Gck+/+ , but not Gck+/- mice. This observation implies that glucokinase in ß-cells would be required for the increase in ß-cell mass induced by HSTD feeding.

Glucokinase Inactivation Paradoxically Ameliorates Glucose Intolerance by Increasing ß-Cell Mass in db/db Mice.

Efficacy of glucokinase activation on glycemic control is limited to a short-term period. One reason might be related to excess glucose signaling by glucokinase activation toward ß-cells. In this study, we investigated the effect of glucokinase haploinsufficiency on glucose tolerance as well as ß-cell function and mass using a mouse model of type 2 diabetes. Our results showed that in db/db mice with glucokinase haploinsufficiency, glucose tolerance was ameliorated by augmented insulin secretion associated with the increase in ß-cell mass when compared with db/db mice. Gene expression profiling and immunohistochemical and metabolomic analyses revealed that glucokinase haploinsufficiency in the islets of db/db mice was associated with lower expression of stress-related genes, greater expression of transcription factors involved in the maintenance and maturation of ß-cell function, less mitochondrial damage, and a superior metabolic pattern. These effects of glucokinase haploinsufficiency could preserve ß-cell mass under diabetic conditions. These findings verified our hypothesis that optimizing excess glucose signaling in ß-cells by inhibiting glucokinase could prevent ß-cell insufficiency, leading to improving glucose tolerance in diabetes status by preserving ß-cell mass. Therefore, glucokinase inactivation in ß-cells, paradoxically, could be a potential strategy for the treatment of type 2 diabetes.

Initial dip predicts renal protective effects after the administration of sodium-glucose cotransporter 2 inhibitors in patients with type 2 diabetes and chronic kidney disease with normoalbuminuria.

INTRODUCTION: We investigated the renoprotective effects of sodium-glucose cotransporter 2 inhibitors (SGLT2is) on renal function in patients with type 2 diabetes and chronic kidney disease (CKD) with normoalbuminuria. METHODS: A retrospective review of clinical records of Japanese participants with type 2 diabetes and CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2) with normoalbuminuria (urine albumin to creatinine ratio < 30 mg/g Cr and/or urinary protein to creatinine ratio < 150 mg/g Cr) was conducted. Participants were categorized into two groups depending on whether they had started using SGLT2is. The main study outcome was a comparison of the change in renal function evaluated by eGFR after 1 year between the two groups. Then, we identified predictors that were associated with the outcome. RESULTS: Among the 46 participants, 21 were treated with SGLT2is (SGLT2 group) and 25 were treated with other antidiabetic medications (control group). Although eGFR was significantly decreased at 1 year in the control group, the decline in eGFR was not observed in the SGLT2 group. The decrease in eGFR was significantly smaller in the SGLT2 group than in the control group. Additionally, multiple linear regression analysis showed that an initial dip was an independent factor associated with the worsening of renal function in the SGLT2 group. CONCLUSIONS: Although more favorable effects of SGLT2is on renal function were observed in patients with type 2 diabetes and CKD with normoalbuminuria, the higher initial dip was a possible marker of worsening renal function after the initiation of SGLT2is.

Factors with remission of fatty liver in patients with type 2 diabetes treated with ipragliflozin.

We investigated the factors associated with fatty liver remission via treatment with ipragliflozin. The analysis was obtained from our multi-center prospective observational study, including 200 Japanese patients with type 2 diabetes treated with ipragliflozin (50 mg/day) for 24 weeks. The extent of fatty liver was estimated using a fatty liver index (FLI). Based on the FLI after the treatment with ipragliflozin, patients were classified into remission group (FLI < 30) and non-remission group (FLI ≥ 30). After treatment with ipragliflozin for 24 weeks, FLI significantly improved from 64.5 ± 21.6 to 51.9 ± 26.5 (p < 0.01). Body weight, body mass index, waist circumference, aspartate aminotransferase, alanine aminotransferase, and FLI in the remission group were significantly lower compared with those of the non-remission group. Stepwise analysis showed that the baseline FLI (Odds ratio 0.86; 95% confidence interval 0.81-0.90, p < 0.01) was an independent factor associated with FLI remission. Using a receiver operating characteristic (ROC) analysis, the adequate cut-off value for the remission was 50. The area under the ROC curve was 0.93 with the sensitivity and specificity 84.6% and 90.1% respectively. In conclusion, ipragliflozin ameliorated fatty liver. These results suggest that patients with fatty liver with a lower FLI are more likely to attain remission by the treatment with ipragliflozin.

Effects of dapagliflozin and/or insulin glargine on beta cell mass and hepatic steatosis in db/db mice.

OBJECTIVE: To explore the beneficial effects of dapagliflozin and/or insulin glargine on the pancreatic beta cell mass and hepatic steatosis in db/db mice. METHODS: Six-week-old db/db mice were assigned to one of four groups: untreated (Placebo), treated with dapagliflozin (Dapa), treated with insulin glargine (Gla), or treated with dapagliflozin and insulin glargine (Dapa+Gla). After 8 weeks of treatment, we determined glucose tolerance, beta cell mass, hepatic lipid content and gene expression. RESULTS: Glucose tolerance was significantly ameliorated in the three treated groups to the same degree compared with the Placebo group. Immunohistochemical analysis revealed that the pancreatic beta cell mass was significantly maintained in the Dapa and Dapa+Gla groups, but not in the Gla group, compared with the Placebo group (Placebo 2.25 ±â€¯1.44 mg, Dapa 5.01 ±â€¯1.63 mg, Gla 3.79 ±â€¯0.96 mg, Dapa+Gla 5.19 ±â€¯1.78 mg). However, the triglyceride content of the liver was markedly elevated in the Gla group compared with that in the other three groups (Placebo 24.1 ±â€¯11.5 mg, Dapa 30.6 ±â€¯12.9 mg, Gla 128 ±â€¯49.7 mg, Dapa+Gla 54.4 ±â€¯14.1 mg per gram liver). The expression levels of genes related to fatty acid synthesis and lipid storage were significantly upregulated in the Gla group. CONCLUSIONS: Our results showed that beta cell mass was sustained and hepatic steatosis was prevented, after 8 weeks of treatment with either dapagliflozin or dapagliflozin plus insulin glargine, but not with insulin glargine alone, in db/db mice.

The Association of Cardio-Ankle Vascular Index and Ankle-Brachial Index with Macroangiopathy in Patients with Type 2 Diabetes Mellitus.

AIMS: This study elucidates the association of macroangiopathy development in type 2 diabetes patients with various arteriosclerosis risk factors (ARFs) and results of cardio-ankle vascular index (CAVI) and ankle-brachial pressure index (ABI). METHODS: The correlation between current and past macroangiopathy development, with ARFs or CAVI/ABI data, was retrospectively analyzed using multivariate logistic regression in 816 patients with type 2 diabetes at a single center. C-statistics combining some independent variables selected using the stepwise method were evaluated. RESULTS: CAVI was significantly correlated with macroangiopathies, including coronary artery disease (CAD), arteriosclerosis obliterans (ASO), and stroke with odds ratios (OR) of 1.20, 1.22, and 1.19, respectively. ABI significantly correlated with ASO and stroke with respective OR of 13.6 and 2.47, but not with CAD. Areas under the receiver operating characteristic curves (ROCs) revealed the accuracy of detecting ASO and stroke was increased by the combination of CAVI＋ABI (0.94 and 0.74, respectively). However, areas under the ROC for the presence of CAD can be increased by the combination of CAVI and ARFs especially including dyslipidemia. CONCLUSION: CAVI/ABI and some ARFs are useful tools in daily clinical care units to identify the current and past existence of macroangiopathy in patients with type 2 diabetes, but the prediction weights using these factors were different among CAD, ASO, and stroke.

Should sulfonylurea be discontinued or maintained at the lowest dose when starting ipragliflozin? A multicenter observational study in Japanese patients with type 2 diabetes.

AIMS/INTRODUCTION: We investigated the difference in efficacy and safety between discontinuation and maintaining of sulfonylurea when adding a sodium-glucose cotransporter 2 inhibitor. MATERIALS AND METHODS: In the present multicenter, prospective observational study, 200 patients with type 2 diabetes treated with sulfonylurea and with a need to add ipragliflozin were enrolled and divided into two groups: discontinued sulfonylurea (Discontinuation group) or maintained sulfonylurea, but at the lowest dose (Low-dose group) when adding ipragliflozin. We compared the two groups after 24 weeks using propensity score matching to adjust for differences between the groups. RESULTS: In the matched cohort (58 patients in each group), baseline characteristics of both groups were balanced. The primary outcome of the proportion of patients with non-exacerbation in glycated hemoglobin after 24 weeks was 91.4% in the Low-dose group and 75.9% in the Discontinuation group, a significant difference (P = 0.024). However, bodyweight was significantly decreased in the Discontinuation group compared with the Low-dose group (-4.4 ± 2.1 kg vs -2.9 ± 1.9 kg, P < 0.01). Similarly, liver enzyme improvement was more predominant in the Discontinuation group. A logistic regression analysis showed that high-density lipoprotein cholesterol, age and sulfonylurea dose were independent factors associated with non-exacerbation of glycated hemoglobin in the Discontinuation group. CONCLUSIONS: The purpose of using ipragliflozin should be considered when making the decision to discontinue or maintain sulfonylurea at the lowest dose. Furthermore, low high-density lipoprotein cholesterol level, low dose of sulfonylurea and younger age were possible markers to not show worsening of glycemic control by discontinuing sulfonylurea.

Effect of the sodium-glucose cotransporter 2 inhibitor luseogliflozin on pancreatic beta cell mass in db/db mice of different ages.

To examine the effects of luseogliflozin, a sodium-glucose cotransporter 2 inhibitor, on pancreatic beta cell mass in db/db mice of different ages. db/db mice aged 6, 10, 14 and 24 weeks old were fed either standard chow (control group) or standard chow containing 0.01% luseogliflozin (luseo group). After 4 weeks, immunohistochemistry and gene expression tests were conducted. In 6-week-old db/db mice, immunohistochemistry revealed a significant increase in beta cell mass in the luseo group compared with the control group after 4 weeks of treatment. Gene expression profiling of isolated islets showed upregulation Mafa, Pdx1, Ki67 and Ccnd2 in the luseo group. Beta cell mass decreased with age in db/db mice in the control group. Beta cell mass in the luseo group significantly increased compared with the control group regardless of age, although beta cell mass in the 28-week-old luseo group (4 weeks of treatment in 24-week-old db/db mice) was significantly lower than in the 10-week-old luseo group (4 weeks of treatment in 6-week-old db/db mice). Luseogliflozin preserved beta cell mass in db/db mice. The protective effect was more evident in the earlier phase of diabetes.

The role of glucokinase and insulin receptor substrate-2 in the proliferation of pancreatic beta cells induced by short-term high-fat diet feeding in mice.

OBJECTIVE: We investigated whether glucokinase and insulin receptor substrate-2 were required for beta cell proliferation induced by short-term high-fat (HF) diet feeding, as has been shown for long-term HF diet. METHODS: Eight-week-old C57BL/6J mice were exposed to either a standard chow (SC) or HF diet. After 1 week on the diet, histopathological beta cell proliferation and gene expression in isolated islets were examined. Additionally, 8-week-old beta cell-specific glucokinase haploinsufficient (Gck+/-) and Irs2 knockout (Irs2-/-) mice were exposed to either an SC or HF diet. RESULTS: Immunohistochemical analysis revealed that short-term HF diet feeding resulted in a significant increase in BrdU incorporation rate compared with SC consumption in wild-type mice. Western blot analysis demonstrated that Irs2 expression levels did not differ between the two diets. Moreover, there was a significant increase in the BrdU incorporation rate in the HF diet group compared with the SC group in both Gck+/- and Irs2-/- mice. Gene expression profiling of isolated islets from mice fed an HF diet for 1 week revealed that the expression levels of downstream genes of Foxm1 were coordinately upregulated. One week of HF diet feeding stimulated beta cell proliferation with Foxm1 upregulation in 48-week-old mice as well as in 8-week-old. CONCLUSIONS: The mechanism of pancreatic beta cell proliferation induced by short-term HF diet feeding in mice could involve a glucokinase- and Irs2-independent pathway. Our results suggest that the pathways that induce beta cell proliferation in response to short-term HF diet feeding may differ from those in response to sustained HF diet feeding.

Factors associated with an inadequate hypoglycemia in the insulin tolerance test in Japanese patients with suspected or proven hypopituitarism.

We attempted to identify the predictors of an inadequate hypoglycemia in insulin tolerance test (ITT), defined as a blood glucose level higher than 2.8 mmol/L after insulin injection, in Japanese patients with suspected or proven hypopituitarism. A total of 78 patients who had undergone ITT were divided into adequate and inadequate hypoglycemia groups. The relationships between the subjects' clinical parameters and inadequate hypoglycemia in ITT were analyzed. Stepwise logistic regression analysis identified high systolic blood pressure (SBP) and high homeostasis model assessment of insulin resistance (HOMA-IR) as being independent factors associated with inadequate hypoglycemia in ITT. Receiver operating characteristic (ROC) curve analysis revealed the cutoff value for inadequate hypoglycemia was 109 mmHg for SBP and 1.4 for HOMA-IR. The areas under ROC curve for SBP and HOMA-IR were 0.72 and 0.86, respectively. We confirmed that high values of SBP and HOMA-IR were associated with inadequate hypoglycemia in ITT, regardless of the degree of reduction of pituitary hormone levels. Furthermore, the strongest predictor of inadequate hypoglycemia was obtained by using the cutoff value of HOMA-IR. Our results suggest that HOMA-IR is a useful pre-screening tool for ITT in these populations.