Periodontal tissue susceptibility to glycaemic control in type 2 diabetes.

AIM: To assess the direct effect of intensive glycaemic control on periodontal tissues in patients with diabetes mellitus. MATERIALS AND METHODS: Twenty-nine patients with type 2 diabetes were enrolled and hospitalized to receive a 2-week intensive glycaemic control regimen. We observed and analysed the systemic and oral disease indicators before and after treatment and clarified the indicators related to periodontal inflammation. RESULTS: A significant reduction in glycaemic and periodontal parameters, including glycated albumin levels and periodontal inflamed surface area (PISA), was observed after treatment. The changes in PISA per tooth, indicative of periodontal healing, exhibited a bimodal distribution; the patients were divided into two groups on this basis. Correlations were observed between the changes in PISA per tooth and fasting plasma glucose, acetoacetic acid, and beta-hydroxybutyrate levels in the PISA-improved group. Significantly lower levels of C-peptide, coefficient of variation of R-R interval, and ankle-brachial pressure index were observed before treatment in the PISA non-improved group. CONCLUSIONS: Glycaemic control treatment can effectively improve periodontitis in patients with type 2 diabetes, even in the absence of specific periodontal treatments. However, the periodontal responsiveness to glycaemic control treatment depends on the systemic condition of the patient.

Continuous glucose monitoring-derived time in range and CV are associated with altered tissue characteristics of the carotid artery wall in people with type 2 diabetes.

AIMS/HYPOTHESIS: Previous studies have suggested that glucose variability may accelerate atherosclerosis progression in people with type 2 diabetes. Current guidelines recommend assessing glycaemic control using continuous glucose monitoring (CGM), which provides a comprehensive glycaemic profile to supplement HbA1c measurement. However, the association between CGM-derived metrics and atherosclerosis progression is not entirely clear. METHODS: This exploratory study used baseline data and data obtained after 104 weeks from an ongoing prospective, multicentre, observational study. Six hundred study participants with type 2 diabetes and no apparent history of symptomatic cardiovascular disease underwent CGM and ultrasonographic atherosclerosis measurements of the carotid arteries, including the intima-media thickness (IMT) and grey-scale median (GSM), at baseline and 104 weeks. Non-invasive ultrasonic tissue characterisation of the carotid artery wall or plaque using the GSM reflects vascular composition. Multivariate regression models were used to analyse the association between CGM-derived indices, mainly time in range (TIR) and CV, and changes in carotid atherosclerosis index values. RESULTS: Over the 104-week study period, there were modest increases in mean IMT (from 0.759±0.153 to 0.773±0.152 mm, p<0.001) and thickened-lesion GSM (from 43.5±19.5 to 53.9±23.5 units, p<0.001), but no significant changes in common carotid artery maximum-IMT (from 1.109±0.442 to 1.116±0.469 mm, p=0.453) or mean GSM (from 48.7±19.3 to 49.8±20.8 units, p=0.092). In a linear regression model with adjustment for possible atherosclerotic risk factors, including HbA1c, TIR and CV at baseline were significantly associated with the annual change in mean GSM (regression coefficient per 10% increase in TIR 0.52; 95% CI 0.06, 0.98; Hochberg-adjusted p value 0.038; regression coefficient per 1% increase in CV -0.12; 95% CI -0.22, -0.02; Hochberg-adjusted p value 0.038). TIR and CV at baseline were also significantly associated with the annual change in thickened-lesion GSM (regression coefficient per 10% increase in TIR 0.95; 95% CI 0.12, 1.79; Hochberg-adjusted p value 0.038; regression coefficient per 1% increase in CV -0.19; 95% CI -0.36, -0.01; Hochberg-adjusted p value 0.038). Participants who achieved target CGM-derived metrics at baseline, as proposed by an international consensus, showed significant annual changes in mean GSM compared with those who did not (0.94±6.88 vs -0.21±6.19 units/year, p=0.007). CONCLUSIONS/INTERPRETATION: TIR and CV were significantly associated with changes in the tissue characteristics of the carotid artery wall. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry, number UMIN000032325.

Tofogliflozin long-term effects on atherosclerosis progression and major clinical parameters in patients with type 2 diabetes mellitus lacking a history of cardiovascular disease: a 2-year extension study of the UTOPIA trial.

BACKGROUND: This study aimed to assess the long-term effects of tofogliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on atherosclerosis progression and major clinical parameters in patients with type 2 diabetes lacking an apparent history of cardiovascular disease. METHODS: This was a prospective observational 2-year extension study of the "Using TOfogliflozin for Possible better Intervention against Atherosclerosis for type 2 diabetes patients (UTOPIA)" trial, a 2-year randomized intervention study. The primary endpoints represented changes in the carotid intima-media thickness (IMT). Secondary endpoints included brachial-ankle pulse wave velocity (baPWV) and biomarkers for glucose metabolism, lipid metabolism, renal function, and cardiovascular risks. RESULTS: The mean IMT of the common carotid artery (IMT-CCA) significantly decreased in both the tofogliflozin (- 0.067 mm, standard error 0.009, p < 0.001) and conventional treatment groups (- 0.080 mm, SE 0.009, p < 0.001) throughout the follow-up period; however, no significant intergroup differences in the changes (0.013 mm, 95% confidence interval (CI) - 0.012 to 0.037, p = 0.32) were observed in a mixed-effects model for repeated measures. baPWV significantly increased in the conventional treatment group (82.7 ± 210.3 cm/s, p = 0.008) but not in the tofogliflozin group (- 17.5 ± 221.3 cm/s, p = 0.54), resulting in a significant intergroup difference in changes (- 100.2 cm/s, 95% CI - 182.8 to - 17.5, p = 0.018). Compared to the conventional treatment group, tofogliflozin significantly improved the hemoglobin A1c and high-density lipoprotein cholesterol levels, body mass index, abdominal circumference, and systolic blood pressure. The frequencies of total and serious adverse events did not vary significantly between the groups. CONCLUSIONS: Tofogliflozin was not associated with improved inhibition of carotid wall thickening but exerted long-term positive effects on various cardiovascular risk factors and baPWV while showing a good safety profile.

Evaluation of the effect of tofogliflozin on the tissue characteristics of the carotid wall-a sub-analysis of the UTOPIA trial.

BACKGROUND: Since sodium-glucose cotransporter 2 (SGLT2) inhibitors have a pleiotropic antiatherogenic effect, they are expected to attenuate the progression of atherosclerosis. However, whether SGLT2 inhibitors affect the tissue characteristics of the human arterial wall remains unclear. This study aimed to evaluate the effects of tofogliflozin, a selective SGLT2 inhibitor, on the tissue characteristics of the human arterial wall in type 2 diabetes (T2DM) patients without apparent cardiovascular disease (CVD). METHODS: The present study was a post hoc analysis based on data obtained from the Using Tofogliflozin for Possible Better Intervention against Atherosclerosis for Type 2 Diabetes Patients (UTOPIA) trial, which was a multicenter prospective, randomized, open-label, blinded-endpoint study conducted to evaluate the efficacy of tofogliflozin in preventing the progression of atherosclerosis in patients with T2DM. We evaluated the longitudinal change in the ultrasonic tissue characteristics of the carotid wall using gray-scale median (GSM), an established index of ultrasonic tissue characteristics. The right and left intima-medial areas were delineated, and the GSM values were evaluated (right GSM-CCA and left GSM-CCA). The average values of the right and left carotid arteries were defined as "mean GSM-CCA value." RESULTS: In a mixed-effects model for repeated measures, mean GSM-CCA, along with the right and left GSM-CCA values, did not significantly change in either the tofogliflozin (n = 168) or conventional treatment group (n = 169). In addition, the tofogliflozin and conventional treatment groups did not significantly differ regarding the change of the mean GSM-CCA (mean difference [95% CI] - 1.24[- 3.87, 1.38], P = 0.35), along with the right (mean difference [95% CI] - 2.33[- 5.70, 1.05], P = 0.18) and the left GSM-CCA (mean difference [95% CI] - 0.29 [- 3.53, 2.95], P = 0.86) values. Similar findings were obtained even after adjusting for traditional cardiovascular risk factors and/or the administration of drugs at baseline. CONCLUSIONS: The tissue characteristics of the carotid arterial wall did not change in either the tofogliflozin or conventional treatment group during the 104-week treatment period, and there was no significant difference between the treatment groups. Clinical trial registration UMIN000017607 ( https://www.umin.ac.jp/icdr/index.html ).

Relationship between blood glucose variability in ambulatory glucose profile and standardized continuous glucose monitoring metrics: Subanalysis of a prospective cohort study.

AIM: To clarify the relationship between ambulatory glucose profile (AGP) indexes and standardized continuous glucose monitoring (CGM) metrics in patients with type 2 diabetes (T2D). METHODS: This is an exploratory, cross-sectional analysis of baseline data collected from a prospective, multicentre, 5-year follow-up observational study conducted and published previously by our group. The study participants were 999 outpatients with T2D who used CGM at baseline, and had no apparent history of cardiovascular disease. We investigated the relationship between average interquartile range (IQR) and time in range (TIR). We also calculated, for the first time, the cutoff values to achieve the TIR target values. RESULTS: In both the TIR more than 70% and TIR more than 90% achievement groups, the average IQR was notably small compared with the non-achievement groups. Particularly in comparison of the TIR quartiles, the average IQR became significantly smaller as the TIR became larger. The average IQR correlated negatively with TIR, and the cutoff values for TIR of more than 70% achievement and TIR of more than 90% achievement were an average IQR (>70%/>90%) of 2.13/1.85 mmol/L. CONCLUSION: Our results showed a negative correlation between TIR and the range of blood glucose variations visually represented in AGP. The results also showed that the range of blood glucose variations in AGP is associated with indices of intraday and interday blood glucose variations and also with hypoglycaemia. Our results may provide new perspectives in the assessment and application of AGP in the clinical setting.

Improvement of beta-cell function in conjunction with glycemic control after medical nutrition therapy in newly-diagnosed type 2 diabetes mellitus.

BACKGROUND: The current study aimed to reveal the correlation of beta-cell function and insulin sensitivity with glycemic control and weight control before and after medical nutrition therapy (MNT) in patients with newly-diagnosed type 2 diabetes mellitus. METHODS: We retrospectively analyzed consecutive 68 patients with newly-diagnosed type 2 diabetes mellitus who started MNT without antihyperglycemic medications and underwent a 75-g oral glucose tolerance test (OGTT) before and after the therapy. Beta-cell function was evaluated by the OGTT-derived disposition index, whereas insulin sensitivity was evaluated by Matsuda's insulin sensitivity index. RESULTS: After 4.0 ± 1.5 months of MNT, mean HbA1c and body mass index significantly decreased from 9.6 ± 1.8% to 7.2 ± 1.0% and from 26.9 ± 4.1 to 25.4 ± 3.7 kg/m2 (both P < 0.001), while the median disposition index and Matsuda's index significantly increased from 0.34 (0.20-0.68) to 0.88 (0.53-1.52) (P < 0.001) and from 4.70 (2.95-5.93) to 5.17 (3.48-6.89) (P = 0.003), respectively. The disposition index was significantly correlated with HbA1c levels both before and after MNT (r = -0.61 and -0.68; both P < 0.001). The magnitude of the correlation after MNT was not different from that before MNT (P = 0.42). Matsuda's index was correlated not with HbA1c levels but with body mass index, both before (r = 0.07 [P = 0.57] and r = -0.58 [P < 0.001]) and after MNT (r = -0.01 [P = 0.95] and r = -0.52 [P < 0.001]). CONCLUSIONS: Beta-cell function was improved in conjunction with glycemic control after MNT in patients with newly-diagnosed type 2 diabetes mellitus. Insulin sensitivity was linked with weight control rather than glycemic control.

Glucotoxicity-induced suppression of Cox6a2 expression provokes ß-cell dysfunction via augmented ROS production.

Oxidative stress is a deteriorating factor for pancreatic ß-cells under chronic hyperglycemia in diabetes. However, the molecular mechanism underlying the increase in oxidative stress in ß-cells under diabetic conditions remains unclear. We demonstrated previously that the selective alleviation of glucotoxicity ameliorated the downregulation of several ß-cell factors, including Cox6a2. Cox6a2 encodes a subunit of the respiratory chain complex IV in mitochondria. In this study, we analyzed the role of Cox6a2 in pancreatic ß-cell function and its pathophysiological significance in diabetes mellitus. Cox6a2-knockdown experiments in MIN6-CB4 cells indicated an increased production of reactive oxygen species as detected by CellROX Deep Red reagent using flow cytometry. In systemic Cox6a2-knockout mice, impaired glucose tolerance was observed under a high-fat high-sucrose diet. However, insulin resistance was reduced when compared with control littermates. This indicates a relative insufficiency of ß-cell function. To examine the transcriptional regulation of Cox6a2, ATAC-seq with islet DNA was performed and an open-chromatin area within the Cox6a2 enhancer region was detected. Reporter gene analysis using this area revealed that MafA directly regulates Cox6a2 expression. These findings suggest that the decreased expression of Cox6a2 increases the levels of reactive oxygen species and that Mafa is associated with decreased Cox6a2 expression under glucotoxic conditions.

Associations of continuous glucose monitoring-assessed glucose variability with intima-media thickness and ultrasonic tissue characteristics of the carotid arteries: a cross-sectional analysis in patients with type 2 diabetes.

BACKGROUND: The association between glucose variability and the progression of atherosclerosis is not completely understood. We aimed to evaluate the associations of glucose variability with the progression of atherosclerosis in the early stages. METHODS: We conducted a cross-sectional analysis to investigate the associations of glucose variability, assessed by continuous glucose monitoring, with intima-media thickness (IMT) and gray-scale median (GSM) of the carotid arteries, which are different indicators for the progression of atherosclerosis. We used baseline data from a hospital-based multicenter prospective observational cohort study among Japanese patients with type 2 diabetes without a history of cardiovascular diseases aged between 30 and 80 years. Continuous glucose monitoring was performed by Freestyle Libre Pro, and glucose levels obtained every 15 min for a maximum of eight days were used to calculate the metrics of glucose variability. IMT and GSM were evaluated by ultrasonography, and the former indicates thickening of intima-media complex in the carotid artery wall, while the latter indicates tissue characteristics. RESULTS: Among 600 study participants (age: 64.9 ± 9.2 (mean ± SD) years; 63.2%: men; HbA1c: 7.0 ± 0.8%), participants with a larger intra- and inter-day glucose variability had a lower GSM and most of these associations were statistically significant. No trend based on glucose variability was shown regarding IMT. Standard deviation of glucose (regression coefficient, ß = - 5.822; 95% CI - 8.875 to - 2.768, P < 0.001), glucose coefficient of variation (ß = - 0.418; - 0.685 to - 0.151, P = 0.002), mean amplitude of glycemic excursion (ß = - 1.689; - 2.567 to - 0.811, P < 0.001), mean of daily differences (ß = - 6.500; - 9.758 to - 3.241, P < 0.001), and interquartile range (ß = - 4.289; - 6.964 to - 1.614, P = 0.002) had a statistically significant association with mean-GSM after adjustment for conventional cardiovascular risk factors, including HbA1c. No metrics of glucose variability had a statistically significant association with IMT. CONCLUSIONS: Continuous glucose monitoring-assessed glucose variability was associated with the tissue characteristics of the carotid artery wall in type 2 diabetes patients without cardiovascular diseases.

Associations between continuous glucose monitoring-derived metrics and arterial stiffness in Japanese patients with type 2 diabetes.

BACKGROUND: Previous studies have suggested that high mean glucose levels and glycemic abnormalities such as glucose fluctuation and hypoglycemia accelerate the progression of atherosclerosis in patients with type 2 diabetes. Although continuous glucose monitoring (CGM) that could evaluate such glycemic abnormalities has been rapidly adopted, the associations between CGM-derived metrics and arterial stiffness are not entirely clear. METHODS: This exploratory cross-sectional study used baseline data from an ongoing prospective, multicenter, observational study with 5 years of follow-up. Study participants included 445 outpatients with type 2 diabetes and no history of apparent cardiovascular disease who underwent CGM and brachial-ankle pulse wave velocity (baPWV) measurement at baseline. Associations between CGM-derived metrics and baPWV were analyzed using multivariate regression models. RESULTS: In a linear regression model, all CGM-derived metrics were significantly associated with baPWV, but HbA1c was not. Some CGM-derived metrics related to intra-day glucose variability, hyperglycemia, and hypoglycemia remained significantly associated with baPWV after adjusting for possible atherosclerotic risk factors, including HbA1c. Based on baPWV ≥ 1800 cm/s as indicative of high arterial stiffness, multivariate logistic regression found that some CGM-derived metrics related to intra-day glucose variability and hyperglycemia are significantly associated with high arterial stiffness even after adjusting for possible atherosclerotic risk factors, including HbA1c. CONCLUSIONS: Multiple CGM-derived metrics are significantly associated with baPWV and high arterial stiffness in patients with type 2 diabetes who have no history of apparent cardiovascular disease. These metrics might be useful for identifying patients at high risk of developing cardiovascular disease.

Effect of tofogliflozin on arterial stiffness in patients with type 2 diabetes: prespecified sub-analysis of the prospective, randomized, open-label, parallel-group comparative UTOPIA trial.

BACKGROUND: Tofogliflozin, an SGLT2 inhibitor, is associated with favorable metabolic effects, including improved glycemic control and serum lipid profile and decreased body weight, visceral adipose tissue, and blood pressure (BP). This study evaluated the effects of tofogliflozin on the brachial-ankle pulse wave velocity (baPWV) in patients with type 2 diabetes (T2DM) without a history of apparent cardiovascular disease. METHODS: The using tofogliflozin for possible better intervention against atherosclerosis for type 2 diabetes patients (UTOPIA) trial is a prospective, randomized, open-label, multicenter, parallel-group, comparative study. As one of the prespecified secondary outcomes, changes in baPWV over 104 weeks were evaluated in 154 individuals (80 in the tofogliflozin group and 74 in the conventional treatment group) who completed baPWV measurement at baseline. RESULTS: In a mixed-effects model, the progression in the right, left, and mean baPWV over 104 weeks was significantly attenuated with tofogliflozin compared to that with conventional treatment (- 109.3 [- 184.3, - 34.3] (mean change [95% CI] cm/s, p = 0.005; - 98.3 [- 172.6, - 24.1] cm/s, p = 0.010; - 104.7 [- 177.0, - 32.4] cm/s, p = 0.005, respectively). Similar findings were obtained even after adjusting the mixed-effects models for traditional cardiovascular risk factors, including body mass index (BMI), glycated hemoglobin (HbA1c), total cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, systolic blood pressure (SBP), hypertension, smoking, and/or administration of drugs, including hypoglycemic agents, antihypertensive agents, statins, and anti-platelets, at baseline. The findings of the analysis of covariance (ANCOVA) models, which included the treatment group, baseline baPWV, and traditional cardiovascular risk factors, resembled those generated by the mixed-effects models. CONCLUSIONS: Tofogliflozin significantly inhibited the increased baPWV in patients with T2DM without a history of apparent cardiovascular disease, suggesting that tofogliflozin suppressed the progression of arterial stiffness. Trial Registration UMIN000017607. Registered 18 May 2015. ( https://www.umin.ac.jp/icdr/index.html ).

Plasma metabolites associated with arterial stiffness in patients with type 2 diabetes.

BACKGROUND: Although an increased arterial stiffness has been associated with traditional coronary risk factors, the risk factors and pathology of arterial stiffness remain unclear. In this study, we aimed to identify the plasma metabolites associated with arterial stiffness in patients with type 2 diabetes mellitus. METHODS: We used the metabolomic data of 209 patients with type 2 diabetes as the first dataset for screening. To form the second dataset for validation, we enlisted an additional 31 individuals with type 2 diabetes. The non-targeted metabolome analysis of fasting plasma samples using gas chromatography coupled with mass spectrometry and the measurement of brachial-ankle pulse wave velocity (baPWV) were performed. RESULTS: A total of 65 annotated metabolites were detected. In the screening dataset, there were statistically significant associations between the baPWV and plasma levels of indoxyl sulfate (r = 0.226, p = 0.001), mannitol (r = 0.178, p = 0.010), mesoerythritol (r = 0.234, p = 0.001), and pyroglutamic acid (r = 0.182, p = 0.008). Multivariate regression analyses revealed that the plasma levels of mesoerythritol were significantly (ß = 0.163, p = 0.025) and that of indoxyl sulfate were marginally (ß = 0.124, p = 0.076) associated with baPWV, even after adjusting for traditional coronary risk factors. In the independent validation dataset, there was a statistically significant association between the baPWV and plasma levels of indoxyl sulfate (r = 0.430, p = 0.016). However, significant associations between the baPWV and plasma levels of the other three metabolites were not confirmed. CONCLUSIONS/INTERPRETATION: The plasma levels of indoxyl sulfate were associated with arterial stiffness in Japanese patients with type 2 diabetes. Although the plasma levels of mannitol, mesoerythritol, and pyroglutamic acid were also associated with arterial stiffness, further investigation is needed to verify the results.

Tofogliflozin does not delay progression of carotid atherosclerosis in patients with type 2 diabetes: a prospective, randomized, open-label, parallel-group comparative study.

BACKGROUND: This study aimed to investigate the preventive effects of tofogliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, on atherosclerosis progression in type 2 diabetes (T2DM) patients without apparent cardiovascular disease (CVD) by monitoring carotid intima-media thickness (IMT). METHODS: This prospective, randomized, open-label, blinded-endpoint, multicenter, parallel-group, comparative study included 340 subjects with T2DM and no history of apparent CVD recruited at 24 clinical units. Subjects were randomly allocated to either the tofogliflozin treatment group (n = 169) or conventional treatment group using drugs other than SGLT2 inhibitors (n = 171). Primary outcomes were changes in mean and maximum common carotid IMT measured by echography during a 104-week treatment period. RESULTS: In a mixed-effects model for repeated measures, the mean IMT of the common carotid artery (mean-IMT-CCA), along with the right and left maximum IMT of the CCA (max-IMT-CCA), significantly declined in both the tofogliflozin (- 0.132 mm, SE 0.007; - 0.163 mm, SE 0.013; - 0.170 mm, SE 0.020, respectively) and the control group (- 0.140 mm, SE 0.006; - 0.190 mm, SE 0.012; - 0.190 mm, SE 0.020, respectively). Furthermore, the tofogliflozin and the conventional treatment group did not significantly differ in the progression of the mean-IMT-CCA (mean change (95% CI) 0.008 (- 0.009, 0.025) mm, P = 0.34), along with the right (mean change (95% CI) 0.027 (- 0.005, 0.059) mm, P = 0.10) and the left max-IMT-CCA (mean change (95% CI) 0.020 (- 0.030, 0.070), P = 0.43). Similar findings were obtained even after adjusting for traditional CV risk factors and/or administration of drugs at baseline. Relative to the control treatment effects, tofogliflozin significantly reduced the HbA1c, blood glucose level, body weight/body mass index, abdominal circumference, and systolic blood pressure, and significantly increased the HDL-C. The total and serious adverse events incidences did not significantly vary between the treatment groups. CONCLUSIONS/INTERPRETATION: No IMT changes were observed between the tofogliflozin and the conventional treatment groups. However, tofogliflozin is a safe and effective treatment option for managing primary CVD risk factors in this population. Clinical Trial Registration UMIN000017607 ( https://www.umin.ac.jp/icdr/index.html ).

Notable Underlying Mechanism for Pancreatic ß-Cell Dysfunction and Atherosclerosis: Pleiotropic Roles of Incretin and Insulin Signaling.

Under healthy conditions, pancreatic ß-cells produce and secrete the insulin hormone in response to blood glucose levels. Under diabetic conditions, however, ß-cells are compelled to continuously secrete larger amounts of insulin to reduce blood glucose levels, and thereby, the ß-cell function is debilitated in the long run. In the diabetic state, expression levels of insulin gene transcription factors and incretin receptors are downregulated, which we think is closely associated with ß-cell failure. These data also suggest that it would be better to use incretin-based drugs at an early stage of diabetes when incretin receptor expression is preserved. Indeed, it was shown that incretin-based drugs exerted more protective effects on ß-cells at an early stage. Furthermore, it was shown recently that endothelial cell dysfunction was also associated with pancreatic ß-cell dysfunction. After ablation of insulin signaling in endothelial cells, the ß-cell function and mass were substantially reduced, which was also accompanied by reduced expression of insulin gene transcription factors and incretin receptors in ß-cells. On the other hand, it has been drawing much attention that incretin plays a protective role against the development of atherosclerosis. Many basic and clinical data have underscored the importance of incretin in arteries. Furthermore, it was shown recently that incretin receptor expression was downregulated in arteries under diabetic conditions, which likely diminishes the protective effects of incretin against atherosclerosis. Furthermore, a series of large-scale clinical trials (SPAED-A, SPIKE, LEADER, SUSTAIN-6, REWIND, PIONEER trials) have shown that various incretin-related drugs have beneficial effects against atherosclerosis and subsequent cardiovascular events. These data strengthen the hypothesis that incretin plays an important role in the arteries of humans, as well as rodents.

Different daily glycemic profiles after switching from once-daily alogliptin plus twice-daily metformin to their once-daily fixed-dose combination in Japanese type 2 diabetic patients.

The aim of this study was to investigate whether daily glycemic profiles and treatment satisfaction would be changed after switching from once-daily 25-mg alogliptin plus twice-daily 250-mg metformin to the fixed-dose combination of 25-mg alogliptin and 500-mg metformin once daily in type 2 diabetic patients. Twenty adult Japanese type 2 diabetic patients in whom once-daily 25-mg alogliptin plus twice-daily 250-mg metformin were switched to the fixed-dose combination of 25-mg alogliptin and 500-mg metformin once daily participated. Before and one month after the switch, participants were asked to perform one day of seven-point self-monitoring of blood glucose (SMBG), to wear a sensor of flash glucose monitoring for up to 14 days, and to respond to a questionnaire for treatment satisfaction. As a result, the SMBG profiles were significantly changed after the switch (p = 0.021); blood glucose levels 2 hours after breakfast were significantly elevated (p = 0.022), whereas those 2 hours after lunch were significantly reduced (p = 0.036). The flash glucose monitoring also demonstrated a significant change of daily glucose profiles (p < 0.001). The risk of glucose levels <80 mg/dL were decreased from evening to morning, while the risk of glucose levels ≥140 mg/dL were increased. Mean 24-hour glucose values were increased by 5 mg/dL on average (p < 0.001). Treatment satisfaction was significantly improved after the switch (p < 0.001). In conclusion, daily glycemic profiles were significantly changed after switching from once-daily 25-mg alogliptin plus twice-daily 250-mg metformin to the once-daily fixed-dose combination in Japanese type 2 diabetic patients. Treatment satisfaction was significantly improved after the switch.

Predictive factors of posttransplant glucose intolerance in Japanese patients with type 1 diabetes after pancreas transplantation.

Pancreas transplantation (PTx) has been performed worldwide for patients with type 1 diabetes accompanied with end-stage renal disease or uncontrollable glycemic fluctuation. Nevertheless, risk factors of posttransplant glucose intolerance, which is responsible for progress of diabetic complications, remains unclear, especially in cases without pancreatic graft function loss. Therefore, this study was conducted to search for predictive factors of future glucose tolerance in PTx recipients without pancreatic graft function loss. Subjects were selected from among 41 Japanese patients with type 1 diabetes who received PTx between 2000 and 2016 in Osaka University Hospital, and 24 subjects free from rejections and thromboses were analyzed. Several examinations to evaluate insulin secretion and insulin sensitivity within 6 months after transplantation (initial examination) were performed. Glucose tolerance was evaluated by 120-minute post-load plasma glucose level during 75-g oral glucose tolerance tests (OGTT), referred to as PGOGTT120, at the initial examination and between 1 year and 2 years posttransplantation (maintenance period). The initial examination factors that were correlated with PGOGTT120 in the maintenance period were PGOGTT120 [r = 0.52 (p = 0.01)], insulinogenic index [r = -0.65 (p < 0.01)], and the ratio of incremental area under the curve of insulin to that of plasma glucose (iAUCR) calculated from data of OGTT [r = -0.65 (p < 0.01)]. Insulinogenic index [ß = -0.28 (p = 0.02)] and iAUCR [ß = -0.29 (p = 0.02)] were still significantly correlated with PGOGTT120 in the maintenance period after adjustment for PGOGTT120 at the initial examination. In conclusion, insulinogenic index and iAUCR from OGTT performed in the early posttransplantation period were predictive factors of future glucose intolerance.

Effect of sitagliptin on tissue characteristics of the carotid wall in patients with type 2 diabetes: a post hoc sub-analysis of the sitagliptin preventive study of intima-media thickness evaluation (SPIKE).

BACKGROUND: Ultrasonic gray-scale median (GSM) of the carotid wall reflects its composition and low-GSM carotid plaque is considered to be vulnerable. This study aimed to evaluate the effect of sitagliptin, a dipeptidyl peptidase-4 inhibitor, on the longitudinal change in GSM, an index of the tissue characteristics of the carotid wall, in patients with type 2 diabetes mellitus (T2DM). METHODS: This is a post hoc sub-analysis using data obtained from the SPIKE trial, a randomized controlled trial that demonstrated the beneficial effect of sitagliptin on the progression of carotid intima-media thickness in patients with T2DM. A total of 274 T2DM patients with no past history of apparent cardiovascular disease (137 in the sitagliptin treatment group and 137 in the conventional treatment group) were enrolled. The primary outcome was the change from baseline in mean GSM-CCA during the 104-week treatment period. RESULTS: The mean GSM-CCA significantly increased in the sitagliptin treatment group (adjusted ΔGSM = 2.40 ± 1.19 [mean ± SE], p = 0.044) but not in the conventional treatment group (adjusted ΔGSM = 1.32 ± 1.19, p = 0.27). However, there was no significant difference in changes in mean GSM-CCA between the treatment groups. CONCLUSIONS: A post hoc sub-analysis suggests that the tissue characteristics of the carotid arterial wall were improved in the sitagliptin treatment group during the 104-week treatment period, but not in the conventional treatment group. However, there was no between-group difference in the changes of GSM values between the two treatment groups. Prespecified studies with large sample sizes would be necessary to confirm our findings. Trial registration UMIN000028664, Registered 15 August 2017 ("retrospectively registered").

Marked recovery from glucotoxicity of ß-cell function after medical nutrition therapy without pharmacotherapy in type 2 diabetic outpatients with extreme hyperglycemia: a pilot retrospective study.

We investigated whether glucotoxicity of ß-cell function could be eliminated after medical nutrition therapy (MNT) without forced correction of hyperglycemia by anti-diabetic medications including exogenous insulin administration. We analyzed newly diagnosed type 2 diabetic outpatients with hemoglobin A1c (HbA1c) of 10.1 ± 1.5%, who were treated by MNT at least for three months, without any aid of anti-diabetic medications. The ß-cell function was calculated as the product of the ΔIns0-120/ΔGlu0-120 and the Matsuda index, where ΔIns0-120/ΔGlu0-120 represents the ratio of the incremental concentrations of insulin to those of glucose during the 0- to 120-min time periods under a 75-g oral glucose tolerance test. After MNT, HbA1c levels were reduced to 7.0 ± 1.0% (p < 0.001). The ß-cell function was significantly improved (n = 13; p = 0.001; effect size d = 1.9). Fasting plasma glucose became below 7.0 mmol/l in 57% (8/13), and 120-minute plasma glucose became below 11.1 mmol/l in 43% (6/13). The ß-cell function after MNT was significantly correlated with HbA1c levels achieved after MNT (Pearson's correlation coefficient r = -0.62, p = 0.025). In conclusion, the ß-cell dysfunction was ameliorated after MNT without glucose-lowering pharmacotherapy in newly diagnosed type 2 diabetic outpatients who presented extreme hyperglycemia.

Ameliorated pancreatic ß cell dysfunction in type 2 diabetic patients treated with a sodium-glucose cotransporter 2 inhibitor ipragliflozin.

It remains to be seen whether pancreatic ß cell dysfunction in type 2 diabetic patients can be ameliorated just by correcting hyperglycemia. The current pilot study investigated ß cell function after a four-week treatment with a sodium-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin in Japanese patients with type 2 diabetes mellitus. Ten participants (age, 51±13 years; hemoglobin A1c levels, 9.4±1.0%) took 50 mg of ipragliflozin L-proline for four weeks and thereafter discontinued the agent for one week. A 75-g oral glucose tolerance test (OGTT) was performed at 0 (baseline), 4 (end of medication), and 5 weeks (end of washout). The ß cell function was evaluated using the disposition index, which was calculated as the product of the ΔIns0₋120/ΔGlu0₋120 and the Matsuda index, where ΔIns0₋120/ΔGlu0₋120 represents the ratio of the incremental concentrations of insulin to those of glucose during the 0- to 120-min time period of the OGTT. The fasting glucose level was 182±34 mg/dL at 0 week, 137±20 mg/dL at 4 weeks (p<0.001), and 154±31 mg/dL at 5 weeks (p=0.001). Compared to baseline, the disposition index was significantly elevated not only at 4 weeks (p<0.001) but also at 5 weeks (p=0.008). In conclusion, the current pilot study showed that the ß cell function assessed by the OGTT-derived disposition index was significantly improved after a four-week treatment with ipragliflozin in Japanese patients with type 2 diabetes mellitus.

An inverse U-shaped association of late and peak insulin levels during an oral glucose load with glucose intolerance in a Japanese population: a cross-sectional study.

The current study investigated the association of post-load insulin levels with glucose tolerance in a Japanese population. A total of 1450 Japanese employees who underwent a 75-g oral glucose tolerance test (OGTT) were included. Glucose tolerance was assessed by 120-min glucose levels during a 75-g OGTT. A penalized cubic regression spline model analysis revealed that the 60- and 120-min insulin levels, but not 0- or 30-min insulin levels, had an inverse U-shaped relationship to the 120-min glucose level. Furthermore, peak insulin level followed an inverse U shape in relation to the 120-min glucose level, whereas the peak of insulin appeared at a later point in time as the 120-min glucose level increased. These associations were similarly observed in both obese and non-obese subgroups, although obesity was associated with higher insulin levels. Peak insulin levels also demonstrated an inverse U shape in association with 0-min glucose levels and indices of ß cell function, assessed by the disposition index and the ß-cell function index. In conclusion, peak insulin levels followed an inverse U shape in relation to glucose intolerance in a Japanese population, whereas the impairment of glucose tolerance was associated with a delay in the time to reach peak insulin levels.

Clinical utility of brachial-ankle pulse wave velocity in the prediction of cardiovascular events in diabetic patients.

BACKGROUND: Brachial-ankle pulse wave velocity (baPWV) is a method to estimate arterial stiffness, which reflects the stiffness of both the aorta and peripheral artery; it would be applicable to general practice, since its measurementis automated. The aim of this study was to evaluate whether baPWV can be predictors of future cardiovascular events (CVE) in diabetic patients. METHODS: We prospectively evaluated the association between baPWV or carotid intima-media thickness (carotid IMT) at baseline and new onset of CVE in 1040 type 2 diabetic patients without CVE. The predictability of baPWV and/or carotid IMT for identifying patients at high risk for CVE was evaluated by time-dependent receiver-operating-characteristic (ROC) curve analysis. RESULTS: During a median follow-up of 7.5 years, 113 had new CVD events. The cumulative incidence rates of CVE were significantly higher in patients with high baPWV values (≥1550 cm/s) as compared to those with low baPWV values (<1550 cm/s) (p < 0.001, log-rank test). Similarly, the cumulative incidence rate of CVE was significantly higher in patients with higher maximum carotid IMT (maxIMT) values (≥1.0 mm) as compared to those with lower maxIMT values (<1.0 mm) (p < 0.001, log-rank test). Subjects with both "high PWV" and "high IMT" had a significantly higher risk of developing CVE as compared to those with either "high PWV" or "high IMT," as well as those with neither. A multivariate Cox proportional hazards regression model revealed that both baPWV (HR = 1.30, [95%CI: 1.07-1.57]; p = 0.009) and maxIMT (HR = 1.20, [95%CI: 1.01-1.41]; p = 0.033) were independent predictors for CVE, even after adjustment for the conventional risk factors. Time-dependent ROC curve analyses revealed that the addition of maxIMT to the Framingham risk score resulted in significant increase in AUC (from 0.60 [95%CI: 0.54-0.67] to 0.63 [95%CI: 0.60-0.82]; p = 0.01). Notably, the addition of baPWV to the Framingham risk score and maxIMT resulted in further and significant (p = 0.02) increase in AUC (0.72 [95%CI: 0.67-0.78]). CONCLUSIONS: Evaluation of baPWV, in addition to carotid IMT and conventional risk factors, improved the ability to identify the diabetic individuals with high risk for CVE.