Favorable Effect of Pemafibrate on Insulin Resistance and ß-Cell Function in Subjects with Type 2 Diabetes and Hypertriglyceridemia: A Subanalysis of the PARM-T2D Study.

Pemafibrate, a novel selective peroxisome proliferator-activated receptor modulator, has beneficial effects on lipid metabolism. However, its effects on glucose metabolism in individuals with type 2 diabetes (T2DM) remain to be fully clarified. This was a subanalysis of the PARM-T2D study, a multicenter prospective observational study on the use of pemafibrate versus conventional therapy for 52 weeks in subjects with T2DM complicated with hypertriglyceridemia. The subanalysis included participants who did not change their treatment for diabetes and did not receive insulin or insulin secretagogues during the study period. Changes in glucose metabolism markers, including homeostatic model assessment (HOMA2) scores and disposition index, were assessed. A total of 279 participants (141 in the pemafibrate group; 138 in the control group) met the criteria for the subanalysis. There were no significant changes in HbA1c during the 52-week study period in both groups. However, the pemafibrate group showed significant improvements versus the control group for insulin resistance assessed by HOMA2-R (-0.15 versus 0.08; estimated treatment difference -0.23 (95% confidence interval -0.44, -0.02); p = 0.03) and maintenance of ß-cell function assessed by disposition index (0.015 versus -0.023; estimated treatment difference 0.037 (95% confidence interval 0.005, 0.069); p = 0.02). Correlation analyses showed that improvements in HOMA2-R and disposition index were significantly associated with improvements in lipid abnormalities and γ-glutamyl transpeptidase. In conclusion, pemafibrate reduced insulin resistance and maintained ß-cell function in subjects with T2DM and hypertriglyceridemia, presumably by improving lipid profiles and lipid-related hepatocyte stress.

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.

Lowering of blood pressure and pulse rate by switching from DPP-4 inhibitor to luseogliflozin in patients with type 2 diabetes complicated with hypertension: A multicenter, prospective, randomized, open-label, parallel-group comparison trial (LUNA study).

AIMS: Sodium-glucose cotransporter-2 inhibitor (SGLT2i) reduces clinic blood pressure (BP), but the effects on BP circadian rhythm remain unclear. The present study aimed to determine the nighttime antihypertensive effect of SGLT2i compared with dipeptidyl peptidase-4 inhibitor (DPP-4i) in patients with type 2 diabetes and hypertension. MATERIALS AND METHODS: In this randomized, open-label, parallel-group trial, patients treated with DPP-4i were either switched to luseogliflozin 2.5 mg/day (Luseo group;n = 30) or continued DPP-4i (DPP-4i group;n = 26). The patients undertook 24-h ambulatory BP monitoring before and 8 weeks after the group allocation. The primary endpoint was mean change in nighttime systolic BP (SBP). RESULTS: Nighttime SBP, as well as daytime SBP, was significantly reduced in the Luseo group compared with the DPP-4i group (nighttime, -4.0 ± 11.4 vs. 3.6 ± 10.7 mmHg,P = 0.01; daytime, -4.4 ± 10.9 vs. 3.7 ± 11.9 mmHg,P = 0.01). Similarly, nighttimepulse rate(PR) was significantly reduced in the Luseo group (-2.0 ± 4.8 vs. 0.9 ± 4.8 bpm,P = 0.03). The proportion of patients with abnormal BP circadian rhythms (non-dipper pattern plus riser pattern) was significantly lower in the Luseo group (36.6% vs. 56.7%,P < 0.05). CONCLUSIONS: Switching from DPP-4i to luseogliflozin decreased nighttime SBP and PR; moreover, BP circadian rhythm was improved.

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.

Improved time in range and postprandial hyperglycemia with canagliflozin in combination with teneligliptin: Secondary analyses of the CALMER study.

AIMS/INTRODUCTION: We recently reported the beneficial effect of the combination of sodium-glucose cotransporter 2 inhibitor and dipeptidyl peptidase-4 inhibitor on daily glycemic variability in patients with type 2 diabetes mellitus. Additional favorable effects of combination therapy were explored in this secondary analysis. MATERIALS AND METHODS: The CALMER study was a multicenter, open-label, prospective, randomized, parallel-group comparison trial for type 2 diabetes mellitus involving continuous glucose monitoring under meal tolerance tests. Patients were randomly assigned to switch from teneligliptin to canagliflozin (SWITCH group) or to add canagliflozin to teneligliptin (COMB group). The continuous glucose monitoring metrics, including time in target range, were investigated. RESULTS: All 99 participants (mean age 62.3 years; mean glycated hemoglobin 7.4%) completed the trial. The time in target range was increased in the COMB group (71.2-82.7%, P < 0.001). The extent of the reduction in time above target range was significantly larger in the COMB group compared with the SWITCH group (-14.8% vs -7.5%, P < 0.01). Area under the curve values for glucose at 120 min after all meal tolerance tests were significantly decreased in the COMB group compared with the SWITCH group (P < 0.05). CONCLUSIONS: Sodium-glucose cotransporter 2 inhibitor combined with dipeptidyl peptidase-4 inhibitor improved the quality of glycemic variability and reduced postprandial hyperglycemia compared with each monotherapy.

Impact of endogenous insulin secretion on the improvement of glucose variability in Japanese patients with type 2 diabetes treated with canagliflozin plus teneligliptin.

AIMS/INTRODUCTION: To identify the effect of combination therapy with a dipeptidyl peptidase-4 inhibitor and a sodium-glucose cotransporter 2 inhibitor compared with switching from a dipeptidyl peptidase-4 inhibitor to a sodium-glucose cotransporter 2 inhibitor on improving the glucose variability in patients with or without impaired endogenous insulin secretion. MATERIALS AND METHODS: A secondary analysis regarding the relationship between endogenous insulin secretion and the change in mean amplitude of glycemic excursions (ΔMAGE) was carried out in a multicenter, prospective, randomized, parallel-group comparison trial that enrolled patients with type 2 diabetes who had been taking teneligliptin and were treated by switching to canagliflozin (SWITCH) or adding canagliflozin (COMB). Participants were categorized into the following four subgroups: SWITCH or COMB and high or low fasting C-peptide (CPR) divided at baseline by the median. RESULTS: ΔMAGE in the COMB group was greatly improved independent of a high or low CPR (-29.2 ± 28.3 vs -20.0 ± 24.6, respectively; P = 0.60). However, ΔMAGE was not ameliorated in the low CPR SWITCH group, and the ΔMAGE was significantly smaller than that in the high CPR COMB group (P < 0.01). CONCLUSIONS: COMB would be a better protocol rather than switching teneligliptin to canagliflozin to improve daily glucose variability in patients with impaired endogenous insulin secretion.

Effects of switching from a dipeptidyl peptidase-4 inhibitor to luseogliflozin on nocturnal blood pressure in patients with type 2 diabetes: protocol for a multicentre, prospective, randomised, open-label, blinded endpoint parallel-group comparison study.

INTRODUCTION: Nocturnal hypertension is clinically important for patients with type 2 diabetes (T2D), considering its strong correlation with cardiovascular events. We aim to test the hypothesis that the sodium-glucose cotransporter 2 inhibitor, luseogliflozin, ameliorates nocturnal hypertension more effectively than a dipeptidyl peptidase (DPP)-4 inhibitor in patients with T2D. METHODS AND ANALYSIS: This study is a multicentre, prospective, randomised, open-label, blinded endpoint parallel-group trial. Sixty participants with T2D and hypertension who have been treated with a DPP-4 inhibitor for more than 4 weeks and who have a glycated haemoglobin A1c (HbA1c) level of 6.0%-9.0% will be randomised based on age, body mass index (BMI) and HbA1c to continue taking their DPP-4 inhibitor or to switch to luseogliflozin 2.5 mg once daily for 8 weeks. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) will be performed twice at baseline and at the end of the study. All participants will continue their diet and exercise therapy, and the doses of concomitant medications will not be adjusted during the study. The primary endpoint is the effect of luseogliflozin on the mean change in systolic blood pressure (SBP) during the night, as measured by ABPM. The secondary endpoints are mean change in diastolic blood pressure (DBP) during the night, 24 hours of SBP and DBP, daytime SBP and DBP, pulse rate, BP M-value, trough SBP and DBP for 1 hour before the next dose, and other laboratory parameters. The sample size was calculated for a two-sided test at 90% power for the detection of a difference between treatments. ETHICS AND DISSEMINATION: The Ethics Review Board of Hokkaido University Hospital has approved the protocol. The results will be disseminated in peer-reviewed journals and at scientific conferences. TRIAL REGISTRATION NUMBERS: The University Hospital Medical Information Network (UMIN000031451); Japan Registry of Clinical Trials (jRCTs011180019); Pre-results.

Favourable effect of the sodium-glucose co-transporter-2 inhibitor canagliflozin plus the dipeptidyl peptidase-4 inhibitor teneligliptin in combination on glycaemic fluctuation: An open-label, prospective, randomized, parallel-group comparison trial (the CALMER study).

This multicentre, prospective, randomized, open-label, blinded-endpoint, parallel-group, short-term (4-5 weeks) controlled trial was conducted to investigate the superiority of the effect of reducing mean amplitude of glycaemic excursions (MAGE) during meal tolerance tests (MTTs) for the combination of dipeptidyl peptidase-4 (DPP-4) inhibitor and sodium-glucose co-transporter-2 (SGLT2) inhibitor compared with SGLT2 inhibitor monotherapy. Ninety-nine patients with type 2 diabetes who were taking teneligliptin (20 mg/d) were randomized to one of the following two groups: those who switched to 100 mg/d of canagliflozin (SWITCH group) or those who added 100 mg/d of canagliflozin (COMB group). MAGE in the COMB group was significantly decreased compared with that in the SWITCH group (COMB 117.5 ± 39.8 to 92.2 ± 28.0 mg/dL vs SWITCH 110.7 ± 29.8 to 104.2 ± 27.6 mg/dL; P<0.01). Mean blood glucose decreased significantly during MTTs in both groups, although the extent of the reduction was significantly greater in the COMB group (COMB 142.3 ± 28.7 to 119.5 ± 25.1 mg/dL vs SWITCH 146.4 ± 25.5 to 135.5 ± 22.4 mg/dL; P < 0.01). SGLT2 inhibitor combined with DPP-4 inhibitor therapy strongly reduced glycaemic fluctuation compared with SGLT2 inhibitor monotherapy.