The oral disposition index calculated from a meal tolerance test is a crucial indicator for evaluating differential normalization of postprandial glucose and triglyceride excursions in morbidly obese patients after laparoscopic sleeve gastrectomy.

To determine the normalization of postprandial blood glucose (PG) and triglyceride (TG) excursions in 30 morbidly obese patients with or without diabetes mellitus (DM) 1-year after they underwent a laparoscopic sleeve gastrectomy (LSG) vs. their pre-surgery data, we administered the 75-g oral glucose tolerance test (OGTT) and a meal tolerance test (MTT) using a 75-g glucose-equivalent carbohydrate- and fat-containing meal. The results were as follows; (i) Postoperative body-weight reduction was associated with DM remission and reduced multiple cardiometabolic risks. (ii) OGTT data showing postprandial hyper-insulinemic hypoglycemia in many post-surgery patients were associated with overdiagnosis of improved glucose tolerance. However, postoperative MTT data without hypoglycemia showed no improvement in the glucose tolerance vs. pre-surgery data. (iii) The disposition index (DI) i.e., [Matsuda index] × (Glucose-induced insulin secretion) was progressively worsened from normal glucose tolerance to DM patients after LSG. These post-surgery DI values measured by the MTT were correlated with 2h-plasma glucose levels and were not normalized in DM patients. (iv) The baseline, 2h-TG, and an increase in 2h-TG values above baseline were correlated with the insulin resistance index, DI, or HbA1c; These TG values were normalized post-LSG. In conclusion, the glucose tolerance curve measured by the MTT was not normalized in T2DM patients, which was associated with impaired normalization of the DI values in those patients 1-year after the LSG. However, the baseline TG and a fat-induced 2h-TG values were normalized postoperatively. The MTT can be used to assess normalization in postprandial glucose and TG excursions after LSG.

Effects of a new 75 g glucose- and high fat-containing cookie meal test on postprandial glucose and triglyceride excursions in morbidly obese patients.

A new meal tolerance test (MTT) using a 75 g glucose- and high fat-containing meal was applied to classify glucose intolerance in morbidly obese patients. According to the MTT data, the concordance rate of diagnosis was 82.5% compared to the 75 g oral glucose tolerance test (OGTT) in patients with normal glucose tolerance (NGT, n = 40). In the NGT patients, the insulinogenic index (r = 0.833), Matsuda index (r = 0.752), and disposition index (r = 0.845) calculated from the MTT data were each significantly (p < 0.001) correlated with those derived from the OGTT data. However, in patients with impaired glucose tolerance (IGT, n = 23) or diabetes mellitus (DM, n = 17), the postprandial glucose levels post-MTT were significantly lower than those post-OGTT, without increases in the postprandial insulin levels post-MTT. Thus, the severity of glucose intolerance measured by the MTT was milder than that indicated by the OGTT. Plasma levels of both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) were increased at the postprandial state, but only the GIP levels post-MTT were significantly higher than those post-OGTT. The enhancement of glucose disposal rates in patients with NGT or IGT after the MTT was associated with increased GIP levels. The postprandial hypertriglyceridemia induced by the MTT was associated with insulin resistance, but it was not associated with the impaired insulinogenic index or the disposition index. These results indicate that the new MTT is clinically useful to evaluate both abnormal glucose and triglyceride excursions caused by abnormal insulin sensitivity and secretions of insulin and gut hormones in morbidly obese patients.

A Prospective, Open-Label Short-Term Pilot Study on Modification of the Skin Hydration Status During Treatment With a Sodium-Glucose Cotransporter-2 Inhibitor.

INTRODUCTION: Various types of skin lesions with pruritus have been reported in participants of Asian clinical trials on sodium-glucose cotransporter-2 (SGLT2) inhibitors. The aim of this study was to determine whether the diuretic effect of a SGLT2 inhibitor could modify skin hydration status in patients with type 2 diabetes mellitus. METHODS: A prospective, short-term, open-label, two-parallel-arm, pilot study was conducted. Eligible patients were assigned to either a SGLT2 inhibitor (50 mg ipragliflozin once daily) group or to a dipeptidyl peptidase-4 inhibitor (50 mg sitagliptin once daily) group (control). The biophysical characteristics of the skin were measured and blood chemistry tests were run in all participants 1 day prior to medication initiation (pre-treatment values) and 14 days thereafter (post-treatment values). RESULTS: Fourteen patients were enrolled in the study, of whom eight were in the ipragliflozin group and six in the sitagliptin group. Compared to the pre-treatment values, the glycated hemoglobin (HbA1c) levels were slightly but significantly reduced in the ipragliflozin group (p = 0.02), but the changes in HbA1c from the pre-treatment to post-treatment time points did not significantly differ between the two treatment groups. Serum 3-hydroxy butyrate levels were significantly higher in the ipragliflozin group than in the sitagliptin group (p < 0.02). Neither electrical capacitance nor electrical conductance of the stratum corneum (SC), parameters that reflect skin water content, was reduced by 14 days of ipragliflozin treatment; similarly, no changes in these parameters were found in the sitagliptin control group. There was also no difference in the changes in water barrier function of the SC between the two treatment groups. There was a significant linear correlation (p < 0.01) in skin water content at pre-treatment and that 14 days after treatment with each drug, respectively. CONCLUSION: Ipragliflozin treatment for 14 days did not significantly affect the skin hydration status in patients with well-controlled type 2 diabetes mellitus.

Preserving ß-cell function is the major determinant of diabetes remission following laparoscopic sleeve gastrectomy in Japanese obese diabetic patients.

Laparoscopic sleeve gastrectomy has been proven effective in treating obesity-associated type 2 diabetes mellitus (T2DM). However, reports of the effect of laparoscopic sleeve gastrectomy on glucose metabolism in Japanese obese patients with T2DM are rare. The aim of this study was to evaluate the effects of laparoscopic sleeve gastrectomy on glucose tolerance in Japanese obese patients with T2DM, and to analyze factors influencing diabetes remission after surgery. This was a retrospective analysis of data for 24 consecutive patients with T2DM who underwent laparoscopic sleeve gastrectomy. We investigated weight loss and its impact on T2DM 1 year postoperatively. We also compared baseline characteristics and postoperative factors between patients who achieved diabetes remission and patients without remission. Mean body weight loss and percent total weight loss were 23.9 kg and 23.3%, respectively. Mean hemoglobin A1c levels dropped from 7.3 ± 0.3% to 6.1 ± 0.2%, and 18 patients (75%) achieved diabetes remission 1 year postoperatively. Patients achieving remission had significantly lower hemoglobin A1c levels (p = 0.026), higher fasting C-peptide values (p < 0.001), shorter diabetes duration (p < 0.001), lower insulin requirement (p = 0.002), and higher area under the insulin response curve (p < 0.001) and insulinogenic index (p < 0.001) during oral glucose tolerance testing. In conclusion, laparoscopic sleeve gastrectomy is an effective treatment for Japanese obese patients with T2DM. Preserving insulin secretion is the major determinant of diabetes remission.

Efficacy of metformin on postprandial plasma triglyceride concentration by administration timing in patients with type 2 diabetes mellitus: A randomized cross-over pilot study.

AIMS/INTRODUCTION: Preprandial metformin administration significantly reduces postprandial plasma triglyceride levels in animal studies by reducing intestinal absorption through delayed gastric emptying. However, this effect has not been shown in a clinical study. Therefore, we planned to investigate the efficacy of preprandial metformin administration on postprandial hypertriglyceridemia and the related gastrointestinal effects in patients with type 2 diabetes mellitus. MATERIALS AND METHODS: A total of 11 patients taking single-dose metformin at 500-1,000 mg, with non-fasting plasma triglyceride levels of 150-1,000 mg/dL, were recruited at a single university hospital. The difference between preprandial and postprandial metformin administration on postprandial hypertriglyceridemia was examined by a meal test. The gastrointestinal effects of metformin, including stomach heaviness, heartburn and satiety, were also assessed using a visual analog scale. RESULTS: The mean bodyweight of patients was 80.6 kg (body mass index 27.9 kg/m2 ), and the mean non-fasting plasma triglyceride level was 275.9 ± 57.0 mg/dL. The area under the curve of triglyceride during the meal test was significantly lower in the preprandial protocol than in the postprandial protocol (P < 0.05). Compared with postprandial administration, preprandial administration of metformin increased satiety (P = 0.036) without stomach heaviness or heartburn. CONCLUSIONS: Preprandial metformin administration significantly reduced plasma triglyceride level during meal testing without marked exacerbation of gastrointestinal adverse effects. The present results suggest that a simple change in the timing of metformin administration represents a novel approach for enhancing triglyceride-lowering strategies in patients with type 2 diabetes mellitus and postprandial hypertriglyceridemia.

Ipragliflozin, a sodium-glucose cotransporter 2 inhibitor, reduces bodyweight and fat mass, but not muscle mass, in Japanese type 2 diabetes patients treated with insulin: A randomized clinical trial.

AIMS/INTRODUCTION: Sodium-glucose cotransporter 2 inhibitors reduce bodyweight (BW) by creating a negative energy balance. Previous reports have suggested that this BW reduction is mainly loss of body fat and that ~20% of the reduction is lean mass. However, the effects of sodium-glucose cotransporter 2 inhibitors on BW and body composition remain unclear. We examined these effects in Japanese patients with type 2 diabetes mellitus treated with insulin. MATERIALS AND METHODS: In this open-label, randomized controlled trial, 49 overweight patients (body mass index ≥23 kg/m2 ) with inadequate glycemic control (hemoglobin A1c >7.0%) receiving insulin treatment were randomly assigned to receive add-on ipragliflozin or no additional treatment (control group). Patients were followed for 24 weeks. The goal for all patients was to achieve glycated hemoglobin <7.0% without hypoglycemia. The primary end-point was a change in BW from baseline to week 24. Body composition was assessed with dual-energy X-ray absorptiometry and bioelectrical impedance analysis. RESULTS: BW change was significantly larger in the ipragliflozin group than in the control group (-2.78 vs -0.22 kg, P < 0.0001). Total fat mass was reduced evenly in the arms, lower limbs and trunk in the ipragliflozin group. Total muscle mass and bone mineral content were maintained, but muscle mass in the arms might have been affected by ipragliflozin treatment. CONCLUSIONS: Ipragliflozin treatment for 24 weeks resulted in reduced BW, mainly from fat mass loss. Muscle mass and bone mineral content were maintained. Further study is necessary to elucidate the long-term effects of ipragliflozin.

MiR-494-3p regulates mitochondrial biogenesis and thermogenesis through PGC1-α signalling in beige adipocytes.

Mitochondria are critical in heat generation in brown and beige adipocytes. Mitochondrial number and function are regulated in response to external stimuli, such as cold exposure and ß3 adrenergic receptor agonist. However, the molecular mechanisms regulating mitochondrial biogenesis during browning, especially by microRNAs, remain unknown. We investigated the role of miR-494-3p in mitochondrial biogenesis during adipogenesis and browning. Intermittent mild cold exposure of mice induced PPARγ coactivator1-α (PGC1-α) and mitochondrial TFAM, PDH, and ANT1/2 expression along with uncoupling protein-1 (Ucp1) in inguinal white adipose tissue (iWAT). miR-494-3p levels were significantly downregulated in iWAT upon cold exposure (p < 0.05). miR-494-3p overexpression substantially reduced PGC1-α expression and its downstream targets TFAM, PDH and MTCO1 in 3T3-L1 white and beige adipocytes (p < 0.05). miR-494-3p inhibition in 3T3-L1 white adipocytes resulted in increased PDH (p < 0.05). PGC1-α, TFAM and Ucp1 mRNA levels were robustly downregulated by miR-494-3p overexpression in 3T3-L1 beige adipocytes, along with strongly decreased oxygen consumption rate. PGC1-α and Ucp1 proteins were downregulated by miR-494-3p in primary beige cells (p < 0.05). Luciferase assays confirmed PGC1-α as a direct gene target of miR-494-3p. Our findings demonstrate that decreased miR-494-3p expression during browning regulates mitochondrial biogenesis and thermogenesis through PGC1-α.

Improved glucose metabolism by Eragrostis tef potentially through beige adipocyte formation and attenuating adipose tissue inflammation.

BACKGROUND: Teff is a staple food in Ethiopia that is rich in dietary fiber. Although gaining popularity in Western countries because it is gluten-free, the effects of teff on glucose metabolism remain unknown. AIM: To evaluate the effects of teff on body weight and glucose metabolism compared with an isocaloric diet containing wheat. RESULTS: Mice fed teff weighed approximately 13% less than mice fed wheat (p < 0.05). The teff-based diet improved glucose tolerance compared with the wheat group with normal chow but not with a high-fat diet. Reduced adipose inflammation characterized by lower expression of TNFα, Mcp1, and CD11c, together with higher levels of cecal short chain fatty acids such as acetate, compared with the control diet containing wheat after 14 weeks of dietary treatment. In addition, beige adipocyte formation, characterized by increased expression of Ucp-1 (~7-fold) and Cidea (~3-fold), was observed in the teff groups compared with the wheat group. Moreover, a body-weight matched experiment revealed that teff improved glucose tolerance in a manner independent of body weight reduction after 6 weeks of dietary treatment. Enhanced beige adipocyte formation without improved adipose inflammation in a body-weight matched experiment suggests that the improved glucose metabolism was a consequence of beige adipocyte formation, but not solely through adipose inflammation. However, these differences between teff- and wheat-containing diets were not observed in the high-fat diet group. CONCLUSIONS: Teff improved glucose tolerance likely by promoting beige adipocyte formation and improved adipose inflammation.

Impact of obesity on annual medical expenditures and diabetes care in Japanese patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: Diabetes and obesity are important health and economic concerns. We investigated the influence of obesity on diabetes control, the annual medical expenditures and medications in Japanese patients with type 2 diabetes who were relatively lean in comparison with those in Western countries. MATERIALS AND METHODS: A total of 402 Japanese patients with type 2 diabetes were enrolled and their annual medical expenditures investigated. Obesity was defined as body mass index ≥25 kg/m2 , according to the obesity classifications from the Japan Society for the Study of Obesity. RESULTS: A total of 165 patients (41.0%) were classified as obese. The obese group was younger, had poor glycemic control and higher frequency of hypertension than the non-obese group. The median total annual medical expenditures for all participants was ¥269,333 (interquartile range ¥169,664-437,437), which was equivalent to approximately $US2,450. The annual medical expenditure was significantly higher in patients with obesity than in non-obese patients (P < 0.001). This difference was mainly attributed to the annual expenditures for medication and hospitalization. In particular, the medication expenditures and the average number of drug classes for hyperglycemia and hypertension were significantly higher in the obese group. CONCLUSIONS: Japanese patients with type 2 diabetes and obesity had higher annual medical expenditures and a larger number of medications, but their diabetes control care was insufficient in comparison with those without obesity. Further studies are required to assess the effect of reducing bodyweight on diabetes control and costs.

Lack of O-GlcNAcylation enhances exercise-dependent glucose utilization potentially through AMP-activated protein kinase activation in skeletal muscle.

O-GlcNAcylation is a post-translational modification that is characterized by the addition of N-acetylglucosamine (GlcNAc) to proteins by O-GlcNAc transferase (Ogt). The degree of O-GlcNAcylation is thought to be associated with glucotoxicity and diabetic complications, because GlcNAc is produced by a branch of the glycolytic pathway. However, its role in skeletal muscle has not been fully elucidated. In this study, we created skeletal muscle-specific Ogt knockout (Ogt-MKO) mice and analyzed their glucose metabolism. During an intraperitoneal glucose tolerance test, blood glucose was slightly lower in Ogt-MKO mice than in control Ogt-flox mice. High fat diet-induced obesity and insulin resistance were reversed in Ogt-MKO mice. In addition, 12-month-old Ogt-MKO mice had lower adipose and body mass. A single bout of exercise significantly reduced blood glucose in Ogt-MKO mice, probably because of higher AMP-activated protein kinase α (AMPKα) protein expression. Furthermore, intraperitoneal injection of 5-aminoimidazole-4-carboxamide ribonucleotide, an AMPK activator, resulted in a more marked decrease in blood glucose levels in Ogt-MKO mice than in controls. Finally, Ogt knockdown by siRNA in C2C12 myotubes significantly increased protein expression of AMPKα, glucose uptake and oxidation. In conclusion, loss of O-GlcNAcylation facilitates glucose utilization in skeletal muscle, potentially through AMPK activation. The inhibition of O-GlcNAcylation in skeletal muscle may have an anti-diabetic effect, through an enhancement of glucose utilization during exercise.

N-3 Polyunsaturated Fatty Acids Decrease the Protein Expression of Soluble Epoxide Hydrolase via Oxidative Stress-Induced P38 Kinase in Rat Endothelial Cells.

N-3 polyunsaturated fatty acids (PUFAs) improve endothelial function. The arachidonic acid-derived metabolites (epoxyeicosatrienoic acids (EETs)) are part of the endothelial hyperpolarization factor and are vasodilators independent of nitric oxide. However, little is known regarding the regulation of EET concentration by docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in blood vessels. Sprague-Dawley rats were fed either a control or fish oil diet for 3 weeks. Compared with the control, the fish oil diet improved acetylcholine-induced vasodilation and reduced the protein expression of soluble epoxide hydrolase (sEH), a key EET metabolic enzyme, in aortic strips. Both DHA and EPA suppressed sEH protein expression in rat aorta endothelial cells (RAECs). Furthermore, the concentration of 4-hydroxy hexenal (4-HHE), a lipid peroxidation product of n-3 PUFAs, increased in n-3 PUFA-treated RAECs. In addition, 4-HHE treatment suppressed sEH expression in RAECs, suggesting that 4-HHE (derived from n-3 PUFAs) is involved in this phenomenon. The suppression of sEH was attenuated by the p38 kinase inhibitor (SB203580) and by treatment with the antioxidant N-acetyl-L-cysteine. In conclusion, sEH expression decreased after n-3 PUFAs treatment, potentially through oxidative stress and p38 kinase. Mild oxidative stress induced by n-3 PUFAs may contribute to their cardio-protective effect.

Acute Effect of Metformin on Postprandial Hypertriglyceridemia through Delayed Gastric Emptying.

Postprandial hypertriglyceridemia is a potential target for cardiovascular disease prevention in patients with diabetic dyslipidemia. Metformin has been reported to reduce plasma triglyceride concentrations in the postprandial states. However, little is known about the mechanisms underlying the triglyceride-lowering effect of metformin. Here, we examined the effects of metformin on lipid metabolism after olive oil-loading in 129S mice fed a high fat diet for three weeks. Metformin administration (250 mg/kg) for one week decreased postprandial plasma triglycerides. Pre-administration (250 mg/kg) of metformin resulted in a stronger triglyceride-lowering effect (approximately 45% lower area under the curve) than post-administration. A single administration (250 mg/kg) of metformin lowered plasma postprandial triglycerides comparably to administration for one week, suggesting an acute effect of metformin on postprandial hypertriglyceridemia. To explore whole body lipid metabolism after fat-loading, stomach size, fat absorption in the intestine, and fat oxidation (13C/12C ratio in expired CO2 after administration of glyceryl-1-13C tripalmitate) were measured with and without metformin (250 mg/kg) pre-treatment. In metformin-treated mice, larger stomach size, lower fat oxidation, and no change in lipid absorption were observed. In conclusion, metformin administration before fat loading reduced postprandial hypertriglyceridemia, most likely by delaying gastric emptying.

Fiber-rich diet with brown rice improves endothelial function in type 2 diabetes mellitus: A randomized controlled trial.

BACKGROUND & AIMS: A fiber-rich diet has a cardioprotective effect, but the mechanism for this remains unclear. We hypothesized that a fiber-rich diet with brown rice improves endothelial function in patients with type 2 diabetes mellitus. METHODS: Twenty-eight patients with type 2 diabetes mellitus at a single general hospital in Japan were randomly assigned to a brown rice (n = 14) or white rice (n = 14) diet and were followed for 8 weeks. The primary outcome was changes in endothelial function determined from flow debt repayment by reactive hyperemia using strain-gauge plethysmography in the fasting state. Secondary outcomes were changes in HbA1c, postprandial glucose excursions, and markers of oxidative stress and inflammation. The area under the curve for glucose after ingesting 250 kcal of assigned rice was compared between baseline (T0) and at the end of the intervention (T1) to estimate glucose excursions in each group. RESULTS: Improvement in endothelial function, assessed by fasting flow debt repayment (20.4% vs. -5.8%, p = 0.004), was significantly greater in the brown rice diet group than the white rice diet group, although the between-group difference in change of fiber intake was small (5.6 g/day vs. -1.2 g/day, p<0.0001). Changes in total, HDL-, and LDL-cholesterol, and urine 8-isoprostane levels did not differ between the two groups. The high-sensitivity C-reactive protein level tended to improve in the brown rice diet group compared with the white rice diet group (0.01 µg/L vs. -0.04 µg/L, p = 0.063). The area under the curve for glucose was subtly but consistently lower in the brown rice diet group (T0: 21.4 mmol/L*h vs. 24.0 mmol/L*h, p = 0.043, T1: 20.4 mmol/L*h vs. 23.3 mmol/L*h, p = 0.046) without changes in HbA1c. CONCLUSIONS: Intervention with a fiber-rich diet with brown rice effectively improved endothelial function, without changes in HbA1c levels, possibly through reducing glucose excursions.

Diverse metabolic effects of O-GlcNAcylation in the pancreas but limited effects in insulin-sensitive organs in mice.

AIMS/HYPOTHESIS: O-GlcNAcylation is characterised by the addition of N-acetylglucosamine to various proteins by O-GlcNAc transferase (OGT) and serves in sensing intracellular nutrients by modulating various cellular processes. Although it has been speculated that O-GlcNAcylation is associated with glucose metabolism, its exact role in whole body glucose metabolism has not been fully elucidated. Here, we investigated whether loss of O-GlcNAcylation globally and in specific organs affected glucose metabolism in mammals under physiological conditions. METHODS: Tamoxifen-inducible global Ogt-knockout (Ogt-KO) mice were generated by crossbreeding Ogt-flox mice with R26-Cre-ERT2 mice. Liver, skeletal muscle, adipose tissue and pancreatic beta cell-specific Ogt-KO mice were generated by crossbreeding Ogt-flox mice with Alb-Cre, Mlc1f-Cre, Adipoq-Cre and Pdx1 PB-CreER™ mice, respectively. Glucose metabolism was evaluated by i.p. glucose and insulin tolerance tests. RESULTS: Tamoxifen-inducible global Ogt-KO mice exhibited a lethal phenotype from 4 weeks post injection, suggesting that O-GlcNAcylation is essential for survival in adult mice. Tissue-specific Ogt deletion from insulin-sensitive organs, including liver, skeletal muscle and adipose tissue, had little impact on glucose metabolism under physiological conditions. However, pancreatic beta cell-specific Ogt-KO mice displayed transient hypoglycaemia (Ogt-flox 5.46 ± 0.41 vs Ogt-ßKO 3.88 ± 0.26 mmol/l) associated with about twofold higher insulin secretion and accelerated adiposity, followed by subsequent hyperglycaemia (Ogt-flox 6.34 ± 0.32 vs Ogt-ßKO 26.4 ± 2.37 mmol/l) with insulin depletion accompanied by beta cell apoptosis. CONCLUSIONS/INTERPRETATION: These findings suggest that O-GlcNAcylation has little effect on glucose metabolism in insulin-sensitive tissues but plays a crucial role in pancreatic beta cell function and survival under physiological conditions. Our results provide novel insight into O-GlcNAc biology and physiology in glucose metabolism.

Pivotal Role of O-GlcNAc Modification in Cold-Induced Thermogenesis by Brown Adipose Tissue Through Mitochondrial Biogenesis.

Adipose tissues considerably influence metabolic homeostasis, and both white (WAT) and brown (BAT) adipose tissue play significant roles in lipid and glucose metabolism. O-linked N-acetylglucosamine (O-GlcNAc) modification is characterized by the addition of N-acetylglucosamine to various proteins by O-GlcNAc transferase (Ogt), subsequently modulating various cellular processes. However, little is known about the role of O-GlcNAc modification in adipose tissues. Here, we report the critical role of O-GlcNAc modification in cold-induced thermogenesis. Deletion of Ogt in WAT and BAT using adiponectin promoter-driven Cre recombinase resulted in severe cold intolerance with decreased uncoupling protein 1 (Ucp1) expression. Furthermore, Ogt deletion led to decreased mitochondrial protein expression in conjunction with decreased peroxisome proliferator-activated receptor γ coactivator 1-α protein expression. This phenotype was further confirmed by deletion of Ogt in BAT using Ucp1 promoter-driven Cre recombinase, suggesting that O-GlcNAc modification in BAT is responsible for cold-induced thermogenesis. Hypothermia was significant under fasting conditions. This effect was mitigated after normal diet consumption but not after consumption of a fatty acid-rich ketogenic diet lacking carbohydrates, suggesting impaired diet-induced thermogenesis, particularly by fat. In conclusion, O-GlcNAc modification is essential for cold-induced thermogenesis and mitochondrial biogenesis in BAT. Glucose flux into BAT may be a signal to maintain BAT physiological responses.

O-linked ß-N-acetylglucosamine modification of proteins is essential for foot process maturation and survival in podocytes.

BACKGROUND: O-linked ß- N -acetylglucosamine modification O-GlcNAcylation) is a post-translational modification of intracellular proteins, serving as a nutrient sensor. Growing evidence has demonstrated its physiological and pathological importance in various mammalian tissues. This study examined the physiological role of O-GlcNAcylation in podocyte function and development. METHODS: O-GlcNAc transferase (Ogt) is a critical enzyme for O-GlcNAcylation and resides on the X chromosome. To abrogate O-GlcNAcylation in podocytes, we generated congenital and tamoxifen (TM)-inducible podocyte-specific Ogt knockout mice (Podo-Ogt y/- and TM-Podo-Ogt y/- , respectively) and analyzed their renal phenotypes. RESULTS: Podo-Ogt y/- mice showed normal podocyte morphology at birth. However, they developed albuminuria at 8 weeks of age, increasing progressively until age 32 weeks. Glomerular sclerosis, proteinuria-related tubulointerstitial lesions and markedly altered podocyte foot processes, with decreased podocin expression, were observed histologically in 32-week-old Podo-Ogt y/- mice. Next, we induced adult-onset deletion of the Ogt gene in podocytes by TM injection in 8-week-old TM-Podo-Ogt y/- mice. In contrast to Podo-Ogt y/- mice, the induced TM-Podo-Ogt y/- mice did not develop albuminuria or podocyte damage, suggesting a need for O-GlcNAcylation to form mature foot processes after birth. To test this possibility, 3-week-old Podo-Ogt y/- mice were treated with Bis-T-23, which stimulates actin-dependent dynamin oligomerization, actin polymerization and subsequent foot process elongation in podocytes. Albuminuria and podocyte damage in 16-week-old Podo-Ogt y/- mice were prevented by Bis-T-23 treatment. CONCLUSIONS: O-GlcNAcylation is necessary for maturation of podocyte foot processes, particularly after birth. Our study provided new insights into podocyte biology and O-GlcNAcylation.

Association between attentional function and postural instability in Japanese older patients with diabetes mellitus.

AIMS: This study assessed the association between attentional function and postural instability in older Japanese patients with diabetes. METHODS: This cross-sectional study included 168 older patients with diabetes who were referred to an outpatient diabetic clinic between June and July 2013. The Trail Making Test-A (TMT-A) was used to evaluate attentional function. Posturography was used to evaluate postural sway. Indices of postural sway were the total length and the enveloped area. Analysis of covariance was used to estimate the multivariable-adjusted means of indices of postural sway according to tertile of TMT-A. RESULTS: After adjustment for age, sex, regular exercise, diabetic retinopathy, bilateral numbness and/or paresthesia in the feet, hemoglobin A1c level, quadriceps strength, and Mini-Mental State Examination score, patients with lower attentional function had higher postural sway length (tertile 3 vs. tertile 1, p = 0.010) and enveloped area (tertile 3 vs. tertile 1, p = 0.030) levels than those with higher attentional function. CONCLUSIONS: Among older patients with diabetes who did not have dementia, patients with lower attentional function may have more postural instability than those with higher attentional function.

Association between symptoms of bilateral numbness and/or paresthesia in the feet and postural instability in Japanese patients with diabetes.

AIM: This study assessed the association between symptoms of bilateral numbness and/or paresthesia in the feet and postural instability in Japanese patients with diabetes. METHODS: This cross-sectional study included 303 patients with diabetes, aged 40-88 years, who were referred to an outpatient diabetic clinic between January and July 2013 at Shiga University of Medical Science Hospital. A posturography test was used to evaluate postural sway in patients. Indices of postural sway were the total length and the enveloped area. Analysis of covariance was used to estimate the multivariable-adjusted means of indices of postural sway according to the presence or absence of symptoms of bilateral numbness and/or paresthesia in the feet. RESULTS: Of 303 patients, 35 (11.6 %) had symptoms of bilateral numbness and/or paresthesia in the feet. After adjustment for age, sex, diabetic retinopathy, regular exercise, body mass index, hemoglobin A1c level, and quadriceps' strength, patients with symptoms had higher levels of postural sway length and an enveloped area in the posturography test than those without symptoms. In addition, we observed similar results when we analyzed 234 patients aged ≥60 years. CONCLUSIONS: Our findings suggest that patients who had symptoms of bilateral numbness and/or paresthesia in the feet may have more postural instability than those without symptoms.

Smoking status is associated with mild cognitive impairment assessed with the mini-mental state examination in Japanese diabetic patients.

AIMS: We assessed the association between smoking status and mild cognitive impairment (MCI) in Japanese diabetic patients. METHODS: This cross-sectional study included 323 diabetic patients, aged 40-79 years, who were referred to an outpatient diabetic clinic between January and July 2013 at Shiga University of Medical Science Hospital (Otsu, Japan). Cognitive function was assessed using the mini-mental state examination (MMSE), and patients were classified into two categories: normal cognitive function (MMSE score ≥27) and MCI (MMSE score 22-26). Logistic regression analysis was used to estimate the multivariable-adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) for MCI in current smokers and ex-smokers compared with never-smokers. RESULTS: Of the 323 patients, 55 (17.0 %), 134 (41.5 %), and 134 (41.5 %) were current smokers, ex-smokers, and never-smokers, respectively. Of these, 68 (21.0 %) patients had MCI. After adjusting for age, sex, systolic blood pressure, body mass index, high-density lipoprotein cholesterol, estimated glomerular filtration rate, hemoglobin A1c, insulin therapy, sulfonylurea, history of coronary heart disease, exercise habit, drinking status, and education, the OR for MCI was 3.62 (95 % CI 1.26-10.40) in current smokers compared with never-smokers. In addition, the multivariable-adjusted ORs for MCI were 3.02 (95 % CI 0.64-14.32) in current smokers <30.0 pack-years and 4.90 (95 % CI 1.32-18.16) in current smokers ≥30.0 pack-years, compared with never-smokers (p for trend = 0.017). CONCLUSIONS: Current smoking, especially current smoking for which cumulative lifetime exposure was high, was associated with MCI, as assessed using the MMSE in Japanese diabetic patients.

A case of local delayed-type allergy to zinc-containing insulin as a cause of diabetic ketoacidosis in a patient with type 1 diabetes mellitus undergoing continuous subcutaneous insulin infusion.

We herein report a case involving a woman with type 1 diabetes and a history of metal allergy who developed a local delayed-type (type IV) allergy to zinc-containing insulin. She had been treated by continuous subcutaneous insulin infusion, but her glycemic control was poor, and she developed diabetic ketoacidosis. Her plasma insulin concentration was unexpectedly low during use of insulin lispro, but it was recovered by changing from the zinc-containing insulin lispro to the zinc-free insulin glulisine. Intradermal tests showed no reactions to various insulins except for zinc chloride. A skin biopsy at the injection site of insulin lispro showed invasion of lymphocytes, neutrophils, and eosinophils, but a skin biopsy at the injection site of insulin glulisine showed invasion of only lymphocytes. A drug lymphocyte stimulation test against polaprezinc, an antiulcer drug containing zinc, was positive. Therefore, we diagnosed the patient with local delayed allergy to zinc-containing insulin. Insulin allergy should be considered as a possible cause of poor glycemic control and diabetic ketoacidosis in patients with type 1 diabetes.