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Purpose: Growth hormone (GH) is a central regulator of β-cell proliferation, insulin secretion and sensitivity. Aim of this study was to investigate the effect of GH insensitivity on pancreatic β-cell histomorphology and consequences for metabolism in vivo. Methods: Pancreata from pigs with growth hormone receptor deficiency (GHR-KO, n = 12) were analyzed by unbiased quantitative stereology in comparison to wild-type controls (WT, n = 12) at 3 and 7–8.5 months of age. In vivo secretion capacity for insulin and glucose tolerance were assessed by intravenous glucose tolerance tests (ivGTTs) in GHR-KO (n = 3) and WT (n = 3) pigs of the respective age groups. Results: Unbiased quantitative stereological analyses revealed a significant reduction in total β-cell volume (83% and 73% reduction in young and adult GHR-KO vs. age-matched WT pigs; p < 0.0001) and volume density of β-cells in the pancreas of GHR-KO pigs (42% and 39% reduction in young and adult GHR-KO pigs; p = 0.0018). GHR-KO pigs displayed a significant, age-dependent increase in the proportion of isolated β-cells in the pancreas (28% in young and 97% in adult GHR-KO vs. age-matched WT pigs; p = 0.0009). Despite reduced insulin secretion in ivGTTs, GHR-KO pigs maintained normal glucose tolerance. Conclusion: GH insensitivity in GHR-KO pigs leads to decreased β-cell volume and volume proportion of β-cells in the pancreas, causing a reduced insulin secretion capacity. The increased proportion of isolated β-cells in the pancreas of GHR-KO pigs highlights the dependency on GH stimulation for proper β-cell maturation. Preserved glucose tolerance accomplished with decreased insulin secretion indicates enhanced sensitivity for insulin in GH insensitivity. [ABSTRACT FROM AUTHOR]

Background: There are several reports on the safety and feasibility of pancreatoduodenectomy (PD) without reconstruction of the small remnant pancreas. However, a few studies have explored central pancreatectomy (CP) for non-reconstructed small remnant pancreases after PD. This study presents a case of CP without pancreatic reconstruction after PD. Case presentation: A 58-year-old man with cerebral palsy underwent PD for distal cholangiocarcinoma. Three years postoperatively, a 12-mm tumor was detected in the remnant pancreatic body and diagnosed as a pancreatic neuroendocrine neoplasm. Surgical resection was performed, because the tumor was enlarged and chemotherapy resistant. The afferent loop with pancreatojejunostomy anastomosis was dissected, and CP, including pancreatojejunostomy anastomosis, was performed. Given the remnant pancreas was hard and atrophic, the pancreatic tail was transected using a stapler without reconstructing the small remnant pancreas. The patient experienced no postoperative complications including postoperative pancreatic fistula, and the endocrine function of the pancreas was preserved. Conclusions: We present a case of remnant pancreatic CP that did not require reconstruction after PD. Preservation of the small remnant pancreas without reconstruction during CP may be feasible to maintain endocrine function in select patients after PD. [ABSTRACT FROM AUTHOR]

Objective: During an oral glucose tolerance test (OGTT), typically fasting plasma glucose is lower than 2-h postprandial plasma glucose. However, postprandial plasma glucose (PPG) levels lower than fasting plasma glucose (FPG) levels may also occur. This study aims to describe the prevalence, clinical characteristics and contributing risk factors for PPG ≤ FPG in a large diverse Chinese population. Methods: We conducted a cross-sectional analysis of baseline data from a nationwide cohort study conducted in China. In addition to sociodemographic and anthropometric data collection, individuals had OGTT and blood chemistry tests. We determined the prevalence of PPG ≤ FPG ('Low Post Load' group) and PPG > FPG ('High Post Load' group) and used logistic regression to evaluate the association of risk factors with the occurrence of Low Post Load. Results: The prevalence of Low Post Load was 26.04% (n = 3773) and High Post Load was 73.96% (n = 10,714). Low Post Load was found to be related to younger age, male, lower BMI, lower blood pressure, higher HDL cholesterol levels and lower triglycerides levels. Compared with participants in the High Post Load group, participants in Low Post Load group had lower PPG (4.59 ± 0.83 mmol/L vs 7.15 ± 1.41 mmol/L) and HbA1c (5.30 ± 0.43% vs 5.39 ± 0.45%). People in Low Post Load group were more likely to have hypoglycaemic episodes (2.12% vs 0.01%) and impaired fasting glucose (12.30% vs 4.81%) compared with people with High Post Load, all p < 0.001. Conclusions: We found a high prevalence of people with Low Post Load glucose (26.04%) in a Chinese population cohort. The relationship between Low Post Load and the progression to or protection from diabetes and related complications and future incidence of cardiovascular disease needs further exploration in longitudinal analyses. [ABSTRACT FROM AUTHOR]

17α-Estradiol (17αE2), a less-feminising enantiomer of 17β-estradiol, has been shown to prolong lifespan and improve metabolic health in a sex-specific manner in male, but not in female mice. Recent studies have demonstrated the pivotal role of estrogen receptor α (ERα) in mediating the effects of 17αE2 on metabolic health. However, the specific tissues and/or neuronal signalling pathways that 17αE2 acts through remain to be elucidated. ERα expression in glutamatergic and GABAergic neurons (principal excitatory and inhibitory neurons respectively) in the hypothalamus is essential for estradiol signalling. Therefore, we hypothesised that knocking out ERα from one of these neuronal populations would attenuate the established beneficial metabolic effects of 17αE2 in male mice exposed to a high fat diet. To test this hypothesis we used two established brain specific ERα KO models, targeting either glutamatergic or GABAergic neurons (Vglut2/Vgat-ERαKO). We show that both of these ERα KO models exhibit a strong reduction in ERα expression in the arcuate nucleus of the hypothalamus, a control centre for metabolic regulation. Deletion of ERα from GABAergic neurons significantly diminished the effect of 17αE2 on body weight relative to controls, although these animals still show metabolic benefits with 17αE2 treatment. The response to 17αE2 was unaffected by ERα deletion in glutamatergic neurons. Our results support a benefit of 17αE2 treatment in protection against metabolic dysfunction, but these effects do not depend on exclusive ERα expression in glutamatergic and GABAergic neurons and persist when ERα expression is strongly reduced in the arcuate nucleus of the hypothalamus. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to compare the effects of fasting for 48 h on the evoked insulin and glucose responses in males and females, and to explore factors such as stress and estrogen levels that might influence these responses. Methods: Healthy, nonobese male (n = 14) and female (n = 14) subjects underwent 48-h fasting trial. Changes in glucose tolerance and insulin levels in response to the oral glucose tolerance test, subjectively perceived stress and catecholamine concentrations were measured in all participants. Estrogen levels were also measured in the female participants during the 48-h fast. Results: Glucose area under the curve (AUC) values increased similarly in both sexes after 48-h fasting (P < 0.05), but females displayed a greater rise in insulin AUC values than males (P < 0.05). Fasting increased plasma epinephrine concentrations in both sexes (P < 0.05), whereas plasma norepinephrine concentrations and subjective stress increased only in females (P < 0.05). Plasma 17-β-estradiol concentrations in females decreased after fasting (P < 0.05). Conclusion: Fasting for 48 h induced a similar glucose intolerance in females and males, despite decreased 17-β-estradiol levels and greater psychological and physiological stress in females. These differences represent a plausible explanation for the gender-based differences observed in insulin responses. Trial registration: Retrospectively registered on ClinicalTrials.gov (NCT05545943) in September 19, 2022. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: As the prevalence of insulin resistance and glucose intolerance is increasing throughout the world, diabetes-induced eye diseases are a global health burden. We aim to identify distinct optical bands which are closely related to insulin and glucose metabolism, using non-invasive, high-resolution spectral domain optical coherence tomography (SD-OCT) in a large, population-based dataset. Methods: The LIFE-Adult-Study randomly selected 10,000 participants from the population registry of Leipzig, Germany. Cross-sectional, standardised phenotyping included the assessment of various metabolic risk markers and ocular imaging, such as SD-OCT-derived thicknesses of ten optical bands of the retina. Global and Early Treatment Diabetic Retinopathy Study (ETDRS) subfield-specific optical retinal layer thicknesses were investigated in 7384 healthy eyes of 7384 participants from the LIFE-Adult-Study stratified by normal glucose tolerance, prediabetes (impaired fasting glucose and/or impaired glucose tolerance and/or HbA1c 5.7–6.4% [39–47 mmol/mol]) and diabetes. The association of optical retinal band characteristics with different indices of glucose tolerance (e.g. fasting glucose, area under the glucose curve), insulin resistance (e.g. HOMA2-IR, triglyceride glucose index), or insulin sensitivity (e.g. estimated glucose disposal rate [eGDR], Stumvoll metabolic clearance rate) was determined using multivariable linear regression analyses for the individual markers adjusted for age, sex and refraction. Various sensitivity analyses were performed to validate the observed findings. Results: In the study cohort, nine out of ten optical bands of the retina showed significant sex- and glucose tolerance-dependent differences in band thicknesses. Multivariable linear regression analyses revealed a significant, independent, and inverse association between markers of glucose intolerance and insulin resistance (e.g. HOMA2-IR) with the thickness of the optical bands representing the anatomical retinal outer nuclear layer (ONL, standardised β=−0.096; p<0.001 for HOMA2-IR) and myoid zone (MZ; β=−0.096; p<0.001 for HOMA2-IR) of the photoreceptors. Conversely, markers of insulin sensitivity (e.g. eGDR) positively and independently associated with ONL (β=0.090; p<0.001 for eGDR) and MZ (β=0.133; p<0.001 for eGDR) band thicknesses. These global associations were confirmed in ETDRS subfield-specific analyses. Sensitivity analyses further validated our findings when physical activity, neuroanatomical cell/tissue types and ETDRS subfield categories were investigated after stratifying the cohort by glucose homeostasis. Conclusions/interpretation: An impaired glucose homeostasis associates with a thinning of the optical bands of retinal ONL and photoreceptor MZ. Changes in ONL and MZ thicknesses might predict early metabolic retinal alterations in diabetes. [ABSTRACT FROM AUTHOR]

Detailed knowledge regarding the associations between intake of different types of seafood and meat and the risk of type 2 diabetes (T2D), and insight into possible mechanisms are warranted. In this study we aimed to evaluate the associations between intake of different types of seafood and meat and the subsequent risk of T2D using the Norwegian Mother, Father, and Child Cohort Study (MoBa), and furthermore, by using a mouse model to gain further insight into possible molecular mechanisms contributing to the associated metabolic changes. Women in MoBa who were free of pharmacologically treated diabetes at baseline (n = 60,777) were prospectively evaluated for incident T2D, identified on the basis of medication usages > 90 days after delivery, ascertained by the Norwegian Prescription Database. Dietary intake was obtained with a validated 255-item food frequency questionnaire which assessed habitual diet during the first 4–5 months of pregnancy. Metabolic phenotypes and plasma metabolome were investigated in female mice fed isocaloric diets with different types of seafood and meat mimicking the dietary intake in the human cohort. During maximum 10-year and mean (SD) 7.2 (1.6) years follow-up time, 681 (1.1%) women developed pharmacologically treated T2D. All statistical models identified a higher risk of T2D with increased shellfish intake, whereas no associations were observed for total seafood, fatty fish, total meat and red meat in the adjusted models. In mice, the shellfish-based western diet induced reduced glucose tolerance and insulin secretion compared to the diet based on lean fish, and we identified a number of metabolites elevated in plasma from shellfish-fed mice that correlated with glucose intolerance. Mice fed a western diet based on meat also exhibited reduced glucose tolerance in comparison to lean fish fed mice, whereas mice fed fatty fish, total seafood or red meat did not differ from lean fish fed mice. We observed a diet-specific metabolic signature in plasma demonstrating five distinct metabolite profiles in mice fed shellfish, fatty fish, total seafood/lean fish, a mixed diet and meat. In conclusion, these findings demonstrate that different types of seafood have different outcome on T2D risk. In women, intake of shellfish was associated with higher risk of T2D. In female mice, a shellfish enriched diet reduced glucose tolerance and altered the abundance of several distinct plasma metabolites correlating with glucose tolerance. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: We aimed to investigate the association between the abundance of Dysosmobacter welbionis, a commensal gut bacterium, and metabolic health in human participants with obesity and diabetes, and the influence of metformin treatment and prebiotic intervention. Methods: Metabolic variables were assessed and faecal samples were collected from 106 participants in a randomised controlled intervention with a prebiotic stratified by metformin treatment (Food4Gut trial). The abundance of D. welbionis was measured by quantitative PCR and correlated with metabolic markers. The in vitro effect of metformin on D. welbionis growth was evaluated and an in vivo study was performed in mice to investigate the effects of metformin and D. welbionis J115T supplementation, either alone or in combination, on metabolic variables. Results: D. welbionis abundance was unaffected by prebiotic treatment but was significantly higher in metformin-treated participants. Responders to prebiotic treatment had higher baseline D. welbionis levels than non-responders. D. welbionis was negatively correlated with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and fasting blood glucose levels in humans with obesity and type 2 diabetes. In vitro, metformin had no direct effect on D. welbionis growth. In mice, D. welbionis J115T treatment reduced body weight gain and liver weight, and improved glucose tolerance to a better level than metformin, but did not have synergistic effects with metformin. Conclusions/interpretation: D. welbionis abundance is influenced by metformin treatment and associated with prebiotic response, liver health and glucose metabolism in humans with obesity and diabetes. This study suggests that D. welbionis may play a role in metabolic health and warrants further investigation. Clinical trial: NCT03852069 [ABSTRACT FROM AUTHOR]

The widely available crop oil is an effective alternative to the increasingly scarce marine fish oil. However, simple alternative strategies have led to declining growth and the edible value of farmed fish. It is worthwhile to explore the effects of micro supplements in diets to improve the tolerance of fish to different dietary lipid sources, which finally optimizes the feeding strategies. This study aimed to investigate the regulation of L-carnitine and dietary oil conditions on nutrient composition, lipid metabolism, and glucose regulation of Rhynchocypris lagowskii. Four diets were prepared according to fish oil, fish oil supplemented with L-carnitine, corn oil, and corn oil supplemented with L-carnitine, and FO, LCFO, CO, and LCCO were labeled, respectively. R. lagowskii was fed experimental diets for 8 weeks, and the glucose tolerance test was performed. The CO diet significantly resulted in higher crude lipid content in muscle but a lower level of serum lipid parameters of R. lagowskii than the FO diet. However, dietary L-carnitine supplementation significantly reduced the crude lipid content in the hepatopancreas and muscle of the fish fed with the CO diet yet increased the serum lipid parameters. Additionally, the crude lipid content of muscle was reduced in the fish fed with an FO diet supplemented with L-carnitine. Compared with the FO diet, the CO diet significantly reduced the ratio of n3/n6 polyunsaturated fatty acid in the hepatopancreas and muscle of R.lagowskii. Dietary L-carnitine supplementation significantly reduced the contents of total saturated fatty acids and total monounsaturated fatty acids in hepatopancreas under both dietary lipid sources. The CO diet significantly up-regulated the expression of genes related to lipid uptake and adipogenesis in hepatopancreas, including lipoprotein lipase (lpl), acetyl-coenzyme A carboxylase alpha (accα), and sterol regulatory element binding protein-1 (srebp1), compared with the FO diet. While dietary L-carnitine supplementation significantly down-regulated the expressions of lpl, accα, srebp1, and fatty acid synthase in hepatopancreas and muscle of fish under both dietary lipid sources, along with up-regulated expression of carnitine palmitoyltransferase 1 in hepatopancreas. Moreover, the fish fed with a CO diet significantly increased the expression of glucose uptake and clearance and significantly down-regulated the expressions of glucose regulation-related genes, including glucose transporter 1, glycogen synthase 1, and phosphofructokinase in hepatopancreas and muscle, resulting in slower glucose uptake and clearance than fish fed with FO diet. Nevertheless, dietary L-carnitine supplementation up-regulated the expression of gluconeogenesis-related genes, including glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in the hepatopancreas of R. lagowskii under both dietary lipid sources. In conclusion, a higher dietary n6 PUFA resulted in lipid deposition, decreased serum lipid parameters, and limited serum glucose utilization of R. lagowskii. While the regulatory effect of L-carnitine on lipid metabolism and glucose utilization of R. lagowskii varies with dietary lipid sources and tissues. [ABSTRACT FROM AUTHOR]

In the current study the effects of metformin and cyanidin on the immune system and intestinal flora in rats with type-2 diabetes was investigated. The findings showed that metformin or cyanidin treatment considerably reduced the rise in body weight and glucose levels induced by type-2 diabetes. The type-2 diabetic rats' glucose tolerance was significantly increased by cyanidin administration comparable to that of metformin. Cyanidin administration resulted in a significant reduction in serum cholesterol and low-density lipoprotein (LDL) levels in rats with type-2 diabetes. Treatment with cyanidin significantly increased the ratio of high-density lipoprotein to low-density lipoprotein in type-2 diabetes rats. Cyanidin administration significantly raised the ratio of Firmicutes to Bacteroidetes in the fecal samples of type-2 diabetic rats compared to the model group. In comparison to the model group, it also significantly raised the levels of Lactobacillusintestinalis, Lactobacillus gasseri, and Lactobacillus reuteri in the type-2 diabetes rats. In type-2 diabetes rat fecal samples, the abundance of Christensenellaceae significantly increased while Enterobacteriaceae and Proteobacteria were found to decrease upon cyanidin administration. Furthermore, cyanidin administration to the rats with type-2 diabetes significantly improved the glucose homeostasis. In conclusion, the study demonstrates that cyanidin enhances glucose homeostasis in rats with type-2 diabetes, potentially through controlling intestinal flora. Thus, cyanidin may be looked into more as a possible therapeutic agent for type 2 diabetes. [ABSTRACT FROM AUTHOR]

The reactive oxygen species (ROS) signaling in the hypothalamus is crucial for energy homeostasis; however, excessive ROS exacerbates oxidative stress and promotes hypothalamic dysfunctioning. Also, the emergence of insulin insensitivity and obesity are directly linked to hypothalamic disturbance. The objective of the present study was to determine the effectiveness of gallic acid (GA) as a therapeutic agent against long-term exposure to a high-fat diet (HFD) on the antioxidant profile in the hypothalamus in correlation with glucose tolerance, insulin resistance, and inflammatory parameters. For the current study total of 24 female Swiss-albino mice were divided into 4 groups, 6 animals each for the duration of 90 days. Group I control, group II HFD, group III HFD + GA (50 mg/kg b. wt orally), and group IV GA (50 mg/kg b. wt orally). At the end of the experiment, biochemical, antioxidative, inflammatory, and histological parameters were assessed. Although there was no change in daily food consumption, the administration of GA in HFD-treated mice resulted in a notable reduction in body weight (p ≤ 0.001) and improved hypothalamic superoxide dismutase (SOD) (p = 0.019), catalase (CAT) (p ≤ 0.001), and glutathione peroxidase (GPx) (p ≤ 0.001) in the HFD-treated group. The administration of GA has reduced (p ≤ 0.001) serum glucose, cholesterol, and triglyceride and increased (p ≤ 0.001) high-density lipoprotein (HDL) levels. Moreover, HFD group for 90 days exhibited a decreased tolerance to a 2-h intraperitoneal glucose tolerance test (GTT). GA has substantially reduced (p ≤ 0.001) insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and serum interleukin (IL)-6 in HFD-treated females. The results emphasize that GA can improve the hypothalamic antioxidative profile and insulin sensitivity along with glucose and lipid metabolism in progressive obesity. Figure depicting the role of gallic acid against hypothalamic oxidative stress, insulin resistance, increased inflammatory marker, dyslipidemia, and diminished glucose tolerance caused by a high-fat diet. Symbol used:→ indicate increase and ↛ indicate suppression of activity. [ABSTRACT FROM AUTHOR]

Cat8 is a C6 zinc cluster transcription activator in yeast. It is generally recognized that the transcription of CAT8 is inhibited and that Cat8 is inactive in the presence of high concentrations of glucose. However, our recent study found that constitutively overexpressed Cat8 played a regulatory role in Saccharomyces cerevisiae in the presence of 20 g/L glucose. To explore the regulatory network of Cat8 at high glucose concentrations, CAT8 was both overexpressed and deleted in this study. Cell growth and glucose consumption in different media were significantly accelerated by the deletion of CAT8, while the lag period was greatly shortened. RNA-seq and genetic modification showed that the deletion of CAT8 changed the type of energy metabolism in yeast cells. Many genes related to the mitochondrial respiratory chain were downregulated, resulting in a reduction in aerobic respiration and the tricarboxylic acid cycle. Meanwhile, both the energy supply of anaerobic ethanol fermentation and the Crabtree effect of S. cerevisiae were enhanced by the deletion of CAT8. CAT8 knockout cells show a higher sugar uptake rate, a higher cell growth rate, and higher tolerance to glucose than the wild-type strain YS58. This study expands the understanding of the regulatory network of Cat8 and provides guidance for modulating yeast cell growth. Key points: • The deletion of CAT8 promoted cell growth of S. cerevisiae. • Transcriptome analysis revealed the regulation network of Cat8 under 1% glucose condition. • CAT8 deletion increases the glucose tolerance of cells by enhancing the Crabtree effect. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to investigate the effect of repeated transforaminal epidural low-dose dexamethasone injections on glucose profiles and pituitary-adrenal axis functions of diabetic and non-diabetic patients with low back pain. Methods: A total of 28 patients (ten diabetic [DM group] and 18 non-diabetic patients [non-DM group]) with low back pain were followed-up. Transforaminal epidural low-dose dexamethasone (1.65 mg) injections were repeated every 7–14 days for 8 weeks. Fasting blood sugar (FBS), hemoglobin A1c (HbA1c), morning plasma adrenocorticotropin (ACTH), and cortisol levels were measured at baseline and during the 8-week follow-up period. Results: There were no significant changes in FBS and HbA1c levels between baseline and 8-week follow-up period in both DM and non-DM groups (difference in FBS [95% confidence Interval, CI]: − 0.6 mg/dL [− 6.4, 5.1], p = 0.83 in the non-DM group, − 0.2 mg/dL [− 26.2, 25.8], p = 0.99 in the DM group; difference in HbA1c [95% CI] − 0.02% [− 0.1, 0.1], p = 0.69 in the non-DM group, 0.04% [− 0.3, 0.4], p = 0.79 in the DM group). There were no significant longitudinal changes in ACTH and cortisol levels (ACTH, p = 0.38 [baseline vs. 8 week], p = 0.58 [non-DM vs. DM]; cortisol, p = 0.52 [baseline vs. 8 week], p = 0.90 [non-DM vs. DM]). Conclusions: Repeated transforaminal epidural low-dose dexamethasone injections provided no significant elevations in blood glucose or suppression of the pituitary-adrenal axis for two months from the first injection in both diabetic and non-diabetic patients. Our results indicate the intermediate-term safety of repeated transforaminal epidural low-dose dexamethasone injections with regard to the effect on glucose profile and pituitary-adrenal axis functions. [ABSTRACT FROM AUTHOR]

Purpose: Metabolic flexibility (MetF), which is a surrogate of metabolic health, can be assessed by the change in the respiratory exchange ratio (RER) in response to an oral glucose tolerance test (OGTT). We aimed to determine the day-to-day reproducibility of the energy expenditure (EE) and RER response to an OGTT, and whether a simulation-based postcalorimetric correction of metabolic cart readouts improves day-to-day reproducibility. Methods: The EE was assessed (12 young adults, 6 women, 27 ± 2 years old) using an Omnical metabolic cart (Maastricht Instruments, Maastricht, The Netherlands) after an overnight fast (12 h) and after a 75-g oral glucose dose on 2 separate days (48 h). On both days, we assessed EE in 7 periods (one 30-min baseline and six 15-min postprandial). The ICcE was performed immediately after each recording period, and capillary glucose concentration (using a digital glucometer) was determined. Results: We observed a high day-to-day reproducibility for the assessed RER (coefficients of variation [CV] < 4%) and EE (CVs < 9%) in the 7 different periods. In contrast, the RER and EE areas under the curve showed a low day-to-day reproducibility (CV = 22% and 56%, respectively). Contrary to our expectations, the postcalorimetric correction procedure did not influence the day-to-day reproducibility of the energy metabolism response, possibly because the Omnical's accuracy was ~ 100%. Conclusion: Our study demonstrates that the energy metabolism response to an OGTT is poorly reproducible (CVs > 20%) even using a very accurate metabolic cart. Furthermore, the postcalorimetric correction procedure did not influence the day-to-day reproducibility. Trial registration NCT04320433; March 25, 2020. [ABSTRACT FROM AUTHOR]

Modern lifestyles often entail lack of sleep. Over time, this shortened sleep can lead to chronic sleep deficiency. Sleep disturbances are known to have particularly powerful effects on cognitive functions, primarily working memory (WM), i.e., the abilities to store and update information, as well as to use it within short periods of time to solve complex cognitive tasks. However, the specific mechanisms underlying the decrease in WM in sleep deprivation are still unclear. As insufficient or disturbed sleep affects the physiological and endocrine processes involved in regulating carbohydrate metabolism, this review hypothesizes that changes in glucose metabolism may be one of the mechanisms producing the effects of sleep disorders on WM. The mechanisms mediating the effects of sleep disturbances on glucose tolerance are discussed and data are presented on the relationship between WM and changes in carbohydrate metabolism. [ABSTRACT FROM AUTHOR]

Purpose: By-products from farmed fish contain large amounts of proteins and may be used for human consumption. The purpose of this study was to investigate cardiometabolic effects and metabolic tolerance in mice consuming fishmeal from salmon by-products, salmon filet or beef. Methods: Female C57BL/6J mice were fed chow, as a healthy reference group, or a high-fat diet for 10 weeks to induce obesity and glucose intolerance. Obese mice were subsequently given isocaloric diets containing 50% of the dietary protein from salmon fishmeal, salmon filet or beef for 10 weeks. Mice were subjected to metabolic phenotyping, which included measurements of body composition, energy metabolism in metabolic cages and glucose tolerance. Lipid content and markers of hepatic toxicity were determined in plasma and liver. Hepatic gene and protein expression was determined with RNA sequencing and immunoblotting. Results: Mice fed fishmeal, salmon filet or beef had similar food intake, energy consumption, body weight gain, adiposity, glucose tolerance and circulating levels of lipids and hepatic toxicity markers, such as p-ALT and p-AST. Fishmeal increased hepatic cholesterol levels by 35–36% as compared to salmon filet (p = 0.0001) and beef (p = 0.005). This was accompanied by repressed expression of genes involved in steroid and cholesterol metabolism and reduced levels of circulating Pcsk9. Conclusion: Salmon fishmeal was well tolerated, but increased hepatic cholesterol content. The high cholesterol content in fishmeal may be responsible for the effects on hepatic cholesterol metabolism. Before introducing fishmeal from salmon by-products as a dietary component, it may be advantageous to reduce the cholesterol content in fishmeal. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: The aim of this study was to develop strategies that identify children from the general population who have late-stage presymptomatic type 1 diabetes and may, therefore, benefit from immune intervention. Methods: We tested children from Bavaria, Germany, aged 1.75–10 years, enrolled in the Fr1da public health screening programme for islet autoantibodies (n=154,462). OGTT and HbA1c were assessed in children with multiple islet autoantibodies for diagnosis of presymptomatic stage 1 (normoglycaemia) or stage 2 (dysglycaemia) type 1 diabetes. Cox proportional hazards and penalised logistic regression of autoantibody, genetic, metabolic and demographic information were used to develop a progression likelihood score to identify children with stage 1 type 1 diabetes who progressed to stage 3 (clinical) type 1 diabetes within 2 years. Results: Of 447 children with multiple islet autoantibodies, 364 (81.4%) were staged. Undiagnosed stage 3 type 1 diabetes, presymptomatic stage 2, and stage 1 type 1 diabetes were detected in 41 (0.027% of screened children), 30 (0.019%) and 293 (0.19%) children, respectively. The 2 year risk for progression to stage 3 type 1 diabetes was 48% (95% CI 34, 58) in children with stage 2 type 1 diabetes (annualised risk, 28%). HbA1c, islet antigen-2 autoantibody positivity and titre, and the 90 min OGTT value were predictors of progression in children with stage 1 type 1 diabetes. The derived progression likelihood score identified substages corresponding to ≤90th centile (stage 1a, n=258) and >90th centile (stage 1b, n=29; 0.019%) of stage 1 children with a 4.1% (95% CI 1.4, 6.7) and 46% (95% CI 21, 63) 2 year risk of progressing to stage 3 type 1 diabetes, respectively. Conclusions/interpretation: Public health screening for islet autoantibodies found 0.027% of children to have undiagnosed clinical type 1 diabetes and 0.038% to have undiagnosed presymptomatic stage 2 or stage 1b type 1 diabetes, with 50% risk to develop clinical type 1 diabetes within 2 years. [ABSTRACT FROM AUTHOR]

Beta-glucosidase (Bgl) is an enzyme with considerable food, beverage, and biofuel processing potential. However, as many Bgls are inhibited by their reaction end product glucose, their industrial applications are greatly limited. In this study, a novel Bgl gene (Bgl1973) was cloned from Leifsonia sp. ZF2019 and heterologously expressed in E. coli. Sequence analysis and structure modeling revealed that Bgl1973 was 748 aa, giving it a molecular weight of 78 kDa, and it showed high similarity with the glycoside hydrolase 3 (GH3) family Bgls with which its active site residues were conserved. By using pNPGlc (p-nitrophenyl-β-D-glucopyranoside) as substrate, the optimum temperature and pH of Bgl1973 were shown to be 50 °C and 7.0, respectively. Bgl1973 was insensitive to most metal ions (12.5 mM), 1% urea, and even 0.1% Tween-80. This enzyme maintained 60% of its original activity in the presence of 20% NaCl, demonstrating its excellent salt tolerance. Furthermore, it still had 83% residual activity in 1 M of glucose, displaying its outstanding glucose tolerance. The Km, Vmax, and kcat of Bgl1973 were 0.22 mM, 44.44 μmol/min mg, and 57.78 s−1, respectively. Bgl1973 had a high specific activity for pNPGlc (19.10 ± 0.59 U/mg) and salicin (20.43 ± 0.92 U/mg). Furthermore, molecular docking indicated that the glucose binding location and the narrow and deep active channel geometry might contribute to the glucose tolerance of Bgl1973. Our results lay a foundation for the studying of this glucose-tolerant β-glucosidase and its applications in many industrial settings. Key points: • A novel β-glucosidase from GH3 was obtained from Leifsonia sp. ZF2019. • Bgl1973 demonstrated excellent glucose tolerance. • The glucose tolerance of Bgl1973 was explained using molecular docking analysis. [ABSTRACT FROM AUTHOR]

Insulin regulates glucose metabolism via both direct hormone interactions with its signaling system and glucose transporters in cells of peripheral tissues and indirectly through the central nervous system. In type 2 diabetes mellitus (T2DM), impaired receptor-mediated transport across the blood–brain barrier leads to insulin deficiency in the brain and causes dysfunctions of eating behavior, thermogenesis, carbohydrate and lipid metabolism. Intranasal insulin (I-I) administration is used as an alternative way of its delivery to increase the hormone level in the brain. A combination of I-I administration with various insulin sensitizers facilitates the restoration of glucose tolerance in a shorter period of time at lower doses of insulin. Such a therapy, combining I-I administration (0.5 IU/rat/day) and intranasally administered total calf brain gangliosides (6 mg/kg/day), was applied here for the first time to treat T2DM rats. Intranasal co-administration of insulin and gangliosides led to the normalization of glucose tolerance in T2DM animals after 4 weeks of treatment, while taken separately, the drugs were less effective. As shown by Western blotting, the increase in hepatic insulin sensitivity may be due to a significant decrease in the expression of a negative insulin signaling regulator protein tyrosine phosphatase 1B (PTP1B) and an increase in the phosphorylation level of the key effector protein kinases Akt at Ser473, GSK3β at Ser9 and p38-MAPK at Thr180/Tyr182. Inhibitory phosphorylation of GSK3β at Ser9 may occur due to the activation of both Akt kinase and p38-MAPK, with the contribution of the latter being, in our opinion, more significant. Since intranasally administered insulin and gangliosides may directly affect brain regions responsible for the regulation of peripheral insulin sensitivity and hepatic carbohydrate metabolism, we concluded that the central mechanism of their action was predominant under conditions used in this study. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Despite a similar fat storing function, visceral (intra-abdominal) white adipose tissue (WAT) is detrimental, whereas subcutaneous WAT is considered to protect against metabolic disease. Recent findings indicate that thermogenic genes, expressed in brown adipose tissue (BAT), can be induced primarily in subcutaneous WAT. Here, we investigate the hypothesis that the Wilms tumour gene product (WT1), which is expressed in intra-abdominal WAT but not in subcutaneous WAT and BAT, suppresses a thermogenic program in white fat cells. Methods: Heterozygous Wt1 knockout mice and their wild-type littermates were examined in terms of thermogenic and adipocyte-selective gene expression. Glucose tolerance and hepatic lipid accumulation in these mice were assessed under normal chow and high-fat diet conditions. Pre-adipocytes isolated from the stromal vascular fraction of BAT were transduced with Wt1-expressing retrovirus, induced to differentiate and analysed for the expression of thermogenic and adipocyte-selective genes. Results: Expression of the thermogenic genes Cpt1b and Tmem26 was enhanced and transcript levels of Ucp1 were on average more than tenfold higher in epididymal WAT of heterozygous Wt1 knockout mice compared with wild-type mice. Wt1 heterozygosity reduced epididymal WAT mass, improved whole-body glucose tolerance and alleviated severe hepatic steatosis upon diet-induced obesity in mice. Retroviral expression of WT1 in brown pre-adipocytes, which lack endogenous WT1, reduced mRNA levels of Ucp1, Ppargc1a, Cidea, Prdm16 and Cpt1b upon in vitro differentiation by 60–90%. WT1 knockdown in epididymal pre-adipocytes significantly lowered Aldh1a1 and Zfp423 transcripts, two key suppressors of the thermogenic program. Conversely, Aldh1a1 and Zfp423 mRNA levels were increased approximately five- and threefold, respectively, by retroviral expression of WT1 in brown pre-adipocytes. Conclusion/interpretation: WT1 functions as a white adipocyte determination factor in epididymal WAT by suppressing thermogenic genes. Reducing Wt1 expression in this and other intra-abdominal fat depots may represent a novel treatment strategy in metabolic disease. [ABSTRACT FROM AUTHOR]

Gut microbiota and its metabolites have been shown to influence multiple physiological mechanisms related to human health. Among microbial metabolites, short-chain fatty acids (SCFA) are modulators of different metabolic pathways. On the other hand, several studies suggested that diet might influence gut microbiota composition and activity thus modulating the risk of metabolic disease, i.e. obesity, insulin resistance and type 2 diabetes. Among dietary component, dietary fibre may play a pivotal role by virtue of its prebiotic effect on fibre-fermenting bacteria, that may increase SCFA production. The aim of this review was to summarize and discuss current knowledge on the impact of dietary fibre as modulator of the relationship between glucose metabolism and microbiota composition in humans. More specifically, we analysed evidence from observational studies and randomized nutritional intervention investigating the relationship between gut microbiota, short-chain fatty acids and glucose metabolism. The possible mechanisms behind this association were also discussed. [ABSTRACT FROM AUTHOR]

Purpose: In our previous study, the maternal high-fat/low-fiber (HF-LF) diet was suggested to induce metabolic disorders and placental dysfunction of the dam, but the effects of this diet on glucose metabolism of neonatal offspring remain largely unknown. Here, a neonatal pig model was used to evaluate the effects of maternal HF-LF diet during pregnancy on glucose tolerance, transition of skeletal muscle fiber types, and mitochondrial function in offspring. Methods: A total of 66 pregnant gilts (Guangdong Small-ear Spotted pig) at day 60 of gestation were randomly divided into two groups: control group (CON group; 2.86% crude fat, 9.37% crude fiber), and high-fat/low-fiber diet group (HF-LF group; 5.99% crude fat, 4.13% crude fiber). Results: The maternal HF-LF diet was shown to impair the glucose tolerance of neonatal offspring, downregulate the protein level of slow-twitch fiber myosin heavy chain I (MyHC I), and upregulate the protein levels of fast-twitch fiber myosin heavy chain IIb (MyHC IIb) and IIx (MyHC IIx) in soleus muscle. Additionally, compared with the CON group, the HF-LF offspring showed inhibition of insulin signaling pathway and decrease in mitochondrial function in liver and soleus muscle. Conclusion: Maternal HF-LF diet during pregnancy impairs glucose tolerance, induces the formation of glycolytic muscle fibers, and decreases the hepatic and muscular mitochondrial function in neonatal piglets. [ABSTRACT FROM AUTHOR]

A β-glucosidase obtained from Thermobifida halotolerans YIM 90462T was expressed in Escherichia coli BL21 and subsequently characterized. The recombinant enzyme ThBGL1A showed optimal activity at 45 °C and pH 6, but also showed high activity from 40 to 55 °C and pH 5.6–6.6. Its half-life activity was 58 min at 50 °C. ThBGL1A exhibited notable cold-adapted activity, retaining 13.1%, 49.4%, and 83.5% of its optimal activity at 5, 25, and 30 °C, respectively. Kinetic characterization revealed an enzymatic turnover (Kcat) of 30 s−1 (cellobiose), 41.8 s−1 (p-nitrophenyl-β-d-glucopyranoside), and 52.6 s−1 (p-nitrophenyl-β-d-galactopyranoside). Moreover, ThBGL1A had high tolerance for salt, xylose, and glucose, which are extremely desirable features for industrial applications. Interestingly, its Ki for glucose was 932 mM and more than 80% of its optimal activity in the presence of 2000 mM xylose. After the addition of ThBGL1A (0.05 mg/ml) to a commercial cellulase reaction system, glucose yields from sugarcane bagasse were increased 20% and 18% after 1 day at 30 °C and 45 °C, respectively. Overall, this work identifies a cold-adapted, salt- and glucose-tolerant β-glucosidase with potential applications in commercial cellulose utilization and the bioenergy industry. [ABSTRACT FROM AUTHOR]

Chromium (III) (Cr(III)) effect on improving glucose, body mass loss, and genomic stability has been extensively studied in models of type 2 diabetes. However, there is a lack of studies evaluating its effect on prediabetes. Thus, this study evaluates the effects of Cr(III) as dietetic supplementation on glucose metabolism, obesity, and genomic stability on prediabetic rat model using high-invert sugar. Male Wistar rats were divided randomly into four treatment groups: (1) control, receiving standard diet (control); (2) prediabetic (PD), receiving a 32% of invert sugar; (3) Cr(III), receiving chromium (III) chloride (CrCl3•6H2O) (58.4 mg/L); and (4) Cr(III) + PD, receiving CrCl3•6H2O in combination with high-invert sugar. Cr(III) supplementation significantly reduced blood glucose (123.00 ± 8.29 mg/dL vs. 115.30 ± 9.31 mg/dL, p = 0.015) and partially reduced area under the 120-min blood glucose response curve (AUC) in PD rats (p = 0.227). Moreover, Cr(III) attenuated weight gain (187.29 ± 38.56 g vs. 167.22 ± 29.30 g, p = 0.004), significantly reducing body mass index (0.68 ± 0.04 g/cm2 vs. 0.63 ± 0.04 g/cm2, p < 0.001), Lee index (0.30 ± 0.01 vs. 0.28 ± 0.01, p < 0.001), and peritoneal fat (p < 0.001). Regarding genomic stability, high-invert sugar, Cr(III), or the combination of both did not produce changes in oxidative stress, DNA damage in pancreas, or cytotoxicity markers. These data suggest that Cr(III) supplementation improved partially glucose metabolism and reduced obesity in rat model PD due to high-invert sugar without influence in genomic stability. [ABSTRACT FROM AUTHOR]

Purpose: Hypothyroidism is associated with a lower metabolic rate, impaired glucose tolerance, and increased responsiveness of sympathetic nervous system to glucose ingestion. The Levothyroxine (LT4) monotherapy is the standard treatment for hypothyroidism; however to what extent this treatment restores the patients' metabolism has not been verified. The aim of this study was to test the hypothesis that standard LT4 therapy may not restore proper metabolic response to carbohydrate ingestion. Methods: Energy expenditure, glucose tolerance, and catecholamine response to glucose ingestion were compared in 18 subjects with pharmacologically compensated hypothyroidism (PCH) and controls, at baseline and during oral glucose tolerance test conditions. Results: Metabolic rate was significantly lower in PCH (P < 0.0001). Glucose tolerance was decreased in this group with no differences in insulin resistance indicators between both groups. Adrenergic activity (P < 0.05) as well as adrenergic reaction to glucose ingestion (P < 0.001) were stronger in PCH. Conclusions: Standard treatment for hypothyroidism does not restore the normal metabolic reaction to carbohydrate which is observed in healthy people. [ABSTRACT FROM AUTHOR]

A novel GH1 β-glucosidase gene (bgla) from marine bacterium was sequenced and expressed in Escherichia coli. After purification by Ni2+ affinity chromatography, the recombinant protein was characterized. The purified recombinant enzyme showed maximum activity at 40 °C, pH 7.5 and was stable between temperatures that range from 4 to 30 °C and over the pH range of 6–10. The enzyme displayed a high tolerance to glucose and maximum stimulation at the presence of 100 mM glucose. To improve glucose tolerance of the enzyme, a site-directed mutation (f171w) was introduced into β-glucosidase. The recombinant F171W showed a higher glucose tolerance than the wild type and maintained more than 40% residual activity at the presence of 4 M glucose. Additionally, the recombinant enzymes showed notable tolerance to ethanol. These properties suggest the enzymes may have potential applications for the fermentation of lignocellulosic sugars and the production of biofuels. [ABSTRACT FROM AUTHOR]

A β-glucosidase gene (bsbgl1a) from Bacillus sp. CGMCC 1.16541 was expressed in Escherichia coli BL21 and subsequently characterized. The amino acid sequence shared 83.64% identity with β-glucosidase (WP_066390903.1) from Fictibacillus phosphorivorans. The recombinant β-glucosidase (BsBgl1A) had a molecular weight of 52.2 kDa and could hydrolyze cellobiose, cellotriose, cellotetrose, p-nitrophenyl-β-d-glucopyranoside (pNPG), and p-nitrophenyl-β-d-xylopyranoside (pNPX). Optimal activity for BsBgl1A was recorded at 45 °C with a pH between 5.6 and 7.6, and 100% of its activity was maintained after a 24 h incubation between pH 4 and 9. Kinetic characterization revealed an enzymatic turnover (Kcat) of 616 ± 2 s−1 (with cellobiose) and 3.5 ± 0.1 s−1 (with p-nitrophenyl-β-d-glucopyranoside). Interestingly, the recombinant enzyme showed cupric ion (Cu2+), sodium dodecyl sulfate (SDS) and alcohol tolerance at 10 mM for Cu2+ and 10% for both SDS and alcohol. Additionally, BsBgl1A had high tolerance for glucose (Ki = 2095 mM), which is an extremely desirable feature for industrial applications. Following the addition of BsBgl1A (0.05 mg/ml) to a commercial cellulase reaction system, glucose yields from sugarcane bagasse increased 100% after 1 day at 45 °C. This work identifies a Cu2+, SDS, alcohol, and glucose tolerant GH1 β-glucosidase with potential applications in the hydrolysis of cellulose for the bioenergy industry. [ABSTRACT FROM AUTHOR]

Aims: Gut microbiota significantly impacts human health and is influenced by dietary changes. We evaluated the effects of diets naturally rich in polyphenols (PP) and/or long-chain n-3 polyunsaturated fatty acids (LCn3) on microbiota composition in an ancillary analysis of a randomized controlled trial in individuals at high cardiometabolic risk. Methods: Seventy-eight individuals with high waist circumference and at least one additional component of the metabolic syndrome were randomized to an isoenergetic 8-week diet: (a) low LCn3 and PP; (b) high LCn3; (c) high PP; or (d) high LCn3 and PP. Microbiota analysis was performed on feces collected before and after the intervention. DGGE analysis of the predominant bacteria, Eubacterium rectale and Blautia coccoides group (Lachnospiraceae, EREC), Clostridium leptum (Ruminococcaceae, CLEPT), Bacteroides spp., Bifidobacteria, and Lactobacillus group was performed. A quantitative real-time PCR was performed for the same group, additionally including Atopobium cluster (Coriobatteriaceae). Before and after the intervention, participants underwent a 75 g OGTT and a high-fat test meal to evaluate glucose and lipid response. Results: Adherence to the four diets was optimal. PP significantly increased microbial diversity (p = 0.006) and CLEPT (p = 0.015), while it reduced EREC (p = 0.044). LCn3 significantly increased the numbers of Bifidobacteria (p = 0.041). Changes in CLEPT numbers correlated with changes in early insulin secretion (r = 0.263, p = 0.030). Changes in Atopobium numbers correlated with postprandial triglycerides in plasma (r = 0.266, p = 0.026) and large VLDL (r = 0.313, p = 0.009), and cholesterol in large VLDL (r = 0.319, p = 0.008). Conclusions: Diets naturally rich in PP or LCn3 influenced gut microbiota composition in individuals at high cardiometabolic risk. These modifications were associated with changes in glucose/lipid metabolism. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Treatment with the α3β4 nicotinic acetylcholine receptor (nAChR) agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), improves glucose tolerance in diet-induced obese (DIO) mice, but the physiological and molecular mechanisms are unknown. Methods: DMPP (10 mg/kg body weight, s.c.) was administered either in a single injection (acute) or daily for up to 14 days (chronic) in DIO wild-type (WT) and Chrnb4 knockout (KO) mice and glucose tolerance, tissue-specific tracer-based glucose metabolism, and insulin signalling were assessed. Results: In WT mice, but not in Chrnb4 KO mice, single acute treatment with DMPP induced transient hyperglycaemia, which was accompanied by high plasma adrenaline (epinephrine) levels, upregulated hepatic gluconeogenic genes, and decreased hepatic glycogen content. In contrast to these acute effects, chronic DMPP treatment in WT mice elicited improvements in glucose tolerance already evident after three consecutive days of DMPP treatment. After seven days of DMPP treatment, glucose tolerance was markedly improved, also in comparison with mice that were pair-fed to DMPP-treated mice. The glycaemic benefit of chronic DMPP was absent in Chrnb4 KO mice. Chronic DMPP increased insulin-stimulated glucose clearance into brown adipose tissue (+69%), heart (+93%), gastrocnemius muscle (+74%) and quadriceps muscle (+59%), with no effect in white adipose tissues. After chronic DMPP treatment, plasma adrenaline levels did not increase following an injection with DMPP. In glucose-stimulated skeletal muscle, we detected a decreased phosphorylation of the inhibitory Ser640 phosphorylation site on glycogen synthase and a congruent increase in glycogen accumulation following chronic DMPP treatment. Conclusions/interpretation: Our data suggest that DMPP acutely induces adrenaline release and hepatic glycogenolysis, while chronic DMPP-mediated activation of β4-containing nAChRs improves peripheral insulin sensitivity independently of changes in body weight via mechanisms that could involve increased non-oxidative glucose disposal into skeletal muscle. [ABSTRACT FROM AUTHOR]

Aims: Glucose-dependent insulinotropic polypeptide (GIP) is released primarily from the proximal small intestine and glucagon-like peptide-1 (GLP-1) from the more distal small intestine and colon. Their relative importance to the incretin effect in health has been contentious in the past, although it now appears that GIP has the dominant role. It is uncertain whether there is a relationship between GIP and GLP-1 secretion. We aimed to evaluate the relationship between plasma GIP and GLP-1 responses to a 75-g oral glucose load in individuals with normal (NGT) and impaired glucose tolerance (IGT). Methods: One hundred healthy subjects had measurements of blood glucose, serum insulin, plasma GIP and GLP-1 concentrations for 240 min after a 300 mL drink containing 75 g glucose. Results: Fifty had NGT and 41 IGT; 9 had type 2 diabetes and were excluded from analysis. In both groups, there were increases in plasma GIP and GLP-1 following the glucose drink, with no difference in the magnitude of the responses between t = 0–240 min. There was a weak relationship between the iAUC0–240 min for GIP and GLP-1 in the combined (r = 0.23, P = 0.015) and in the IGT (r = 0.34, P = 0.01), but not in the NGT (r = 0.15, P = 0.14) group. Conclusions: There is a weak relationship between oral glucose-induced GIP and GLP-1 secretions in non-diabetic subjects. [ABSTRACT FROM AUTHOR]

Aims: Recent studies have suggested a possible association between microbiota and gestational diabetes (GDM). However, the results are inconsistent. Our objective was to investigate further the relationship between GDM and microbiota and verify the potential microbial marker. Methods: Two complementary approaches were used for the demonstration. First, we compared the gut microbial composition of 23 GDM patients and 26 non-GDM ethnically Chinese Han pregnant women, by using whole-metagenome shotgun sequencing of their stool samples collected at the third trimester. Second, we used Q-PCR (quantitative polymerase chain reaction) to evaluate the gut microbial composition in the stool samples from another cohort of 150 Chinese pregnant women (113 Control and 37 GDM), to further confirm the potential microbial marker. Results: The gut microbiota of GDM women show lower albeit not statistically significant (p = 0.18) alpha diversity at the species level than non-GDM women. However, the species-level beta-diversity or between-sample diversity measured by Bray–Curtis distance shows significant differences (p < 2.2e−16) between the two groups. The species Bacteroides dorei positively correlated with both OGTT (oral glucose tolerance test) 0-Hour (p = 0.0099) and OGTT 1-Hour (p = 0.0070). There is a similar trend between Bacteroides sp. 3_1_33FAA and both OGTT 0-Hour (p = 0.014) and OGTT 1-Hour (p = 0.0101) response variables. The species Alistipes putredinis negatively correlated with OGTT 1-Hour (p = 0.0172) and OGTT 2-Hour (p = 0.0147). Q-PCR validation further confirmed the association between the glucose tolerance loci of Bacteroides dorei and OGTT response. Conclusions: Gut microbiome is related to the diabetic status of Chinese women during pregnancy. Specific species such as Bacteroides dorei associate with glucose response and could be potential monitoring and therapeutic microbial markers for GDM. [ABSTRACT FROM AUTHOR]

The circadian system generates endogenous rhythms of approximately 24 h, the synchronisation of which are vital for healthy bodily function. The timing of many physiological processes, including glucose metabolism, are coordinated by the circadian system, and circadian disruptions that desynchronise or misalign these rhythms can result in adverse health outcomes. In this review, we cover the role of the circadian system and its disruption in glucose metabolism in healthy individuals and individuals with type 2 diabetes mellitus. We begin by defining circadian rhythms and circadian disruption and then we provide an overview of circadian regulation of glucose metabolism. We next discuss the impact of circadian disruptions on glucose control and type 2 diabetes. Given the concurrent high prevalence of type 2 diabetes and circadian disruption, understanding the mechanisms underlying the impact of circadian disruption on glucose metabolism may aid in improving glycaemic control. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Experimental studies suggest that the fatty acid palmitoleate may act as an adipocyte-derived lipid hormone (or 'lipokine') to regulate systemic metabolism. We investigated the relationship of circulating palmitoleate with insulin sensitivity, beta cell function and glucose tolerance in humans. Methods: Plasma NEFA concentration and composition were determined in non-diabetic individuals from the Relationship between Insulin Sensitivity and Cardiovascular disease (RISC) study cohort at baseline (n = 1234) and after a 3 year follow-up (n = 924). Glucose tolerance, insulin secretion and beta cell function were assessed during an OGTT. Whole-body insulin sensitivity was measured by a hyperinsulinaemic–euglycaemic clamp (M/I) and OGTT (oral glucose insulin sensitivity index [OGIS]). The liver insulin resistance index was calculated using clinical and biochemical data. Body composition including fat mass was determined by bioelectrical impedance. Results: Circulating palmitoleate was proportional to fat mass (r = 0.21, p < 0.0001) and total NEFA levels (r = 0.19, p < 0.0001). It correlated with whole-body insulin sensitivity (M/I: standardised regression coefficient [std. β] = 0.16, p < 0.0001), liver insulin resistance (std. β = −0.14, p < 0.0001), beta cell function (potentiation: std. β = 0.08, p = 0.045) and glucose tolerance (2 h glucose: std. β = −0.24, p < 0.0001) after adjustment for age, sex, BMI, adiposity and other NEFA. High palmitoleate concentrations prevented the decrease in insulin sensitivity associated with excess palmitate (p = 0.0001). In a longitudinal analysis, a positive independent relationship was observed between changes in palmitoleate and insulin sensitivity over time (std. β = 0.07, p = 0.04). Conclusions/interpretation: We demonstrated that plasma palmitoleate is an independent determinant of insulin sensitivity, beta cell function and glucose tolerance in non-diabetic individuals. These results support the role of palmitoleate as a beneficial lipokine released by adipose tissue to prevent the negative effects of adiposity and excess NEFA on systemic glucose metabolism. [ABSTRACT FROM AUTHOR]

The lycopene content of tomatoes is important because of its effects on vital physiological functions such as improvement of glucose tolerance and non-alcoholic fatty liver disease. To investigate the influence of the lycopene content of tomatoes on glucose tolerance and hepatic lipid content, homogenates of lycopene-rich (LR) or lycopene-free negative control (NC) tomato varieties were administrated to normal rats for 4 weeks. At the end of the experiment, an oral glucose tolerance test (OGTT) was performed. Rats were fed once and then dissected. According to the OGTT results, plasma glucose levels in the LR group were 10% and 9% lower at 15 min and 30 min, respectively, than those in the NC group, whereas plasma insulin levels did not differ between the groups at either time point. Upon dissection, plasma leptin levels in the LR group were higher than those in the NC group, while plasma adiponectin levels did not differ between groups. With the exception of retinol palmitate, no carotenoids were detected in the liver by HPLC analysis. Hepatic retinol palmitate levels and hepatic triacyl glyceride levels did not differ between the groups. We concluded that in normal rats, a lycopene-rich tomato variety improved glucose tolerance via an increase in plasma leptin levels that enhanced insulin sensitivity but did not affect carotenoid accumulation or lipid metabolism. [ABSTRACT FROM AUTHOR]

The effects of bariatric surgeries (sleeve gastrectomy and ileal transposition) on the dynamics of changes in ghrelin level were studied in rats with severe decompensated type 2 diabetes mellitus under conditions of glucose challenge as well as on the size of myocardial infarction in these animals. Diabetes was modelled by high fat diet and a single administration of streptozotocin (25 mg/kg, intraperitoneally). Both bariatric surgeries significantly decreased glucose-induced ghrelin level in the blood of rats with type 2 diabetes mellitus, which attested to an increase in the tissue sensitivity to ghrelin. Sleeve gastrectomy resulted in a decrease in the size of myocardial infarction in diabetic rats, which was calculated as the ratio of the necrosis zone to the zone of the risk of myocardial infarction. Ileal transposition had no effect on this parameter. Our data can be used as the basis for optimization of treatment approaches when using bariatric surgery in the treatment of patients with severe forms of type 2 diabetes mellitus with a high risk of cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Aims: Eating protein before carbohydrate reduces postprandial glucose excursions by enhancing insulin and glucagon-like peptide-1 (GLP-1) secretion in type 2 diabetes (T2D). We tested the hypothesis that this insulinotropic effect depends on the elevation of plasma amino acids (AA) after the digestion of food protein. Methods: In 16 T2D patients, we measured plasma AA levels through the course of two 75-g oral glucose tolerance tests (OGTT) preceded by either 500-ml water or a high-protein nutrient preload (50-g Parmesan cheese, one boiled egg, and 300-ml water). Changes in beta cell function were evaluated by measuring and modelling plasma glucose, insulin, and C-peptide through the OGTT. Changes in incretin hormone secretion were assessed by measuring plasma GLP-1. Results: Plasma AA levels were 24% higher after the nutrient preload (p < 0.0001). This increment was directly proportional to both the enhancement of beta cell function (r = 0.58, p = 0.02) and the plasma GLP-1 gradients (r = 0.57, p = 0.02) produced by the nutrient preload. Among single AA, glutamine showed the strongest correlation with changes in beta cell function (r = 0.61, p = 0.01), while leucine showed the strongest correlation with GLP-1 responses (r = 0.74, p = 0.001). Conclusions: The elevation of circulating AA that occurs after a high-protein nutrient preload is associated with an enhancement of beta cell function and GLP-1 secretion in T2D. Manipulating the meal sequence of nutrient ingestion may reduce postprandial hyperglycaemia through a direct and GLP-1-mediated stimulation of insulin secretion by plasma AA. Trial registration number: NCT02342834. [ABSTRACT FROM AUTHOR]

Gestational glucose homeostasis influences mother's metabolic health, pregnancy outcomes, fetal development and offspring growth. To understand the genetic roles in pregnant glucose metabolism and genetic predisposition for gestational diabetes (GDM), we reviewed the recent literature up to Jan, 2018 and evaluated the influence of T2DM-related genetic variants on gestational glycemic traits and glucose tolerance. A total of 140 variants of 89 genes were integrated. Their associations with glycemic traits in and outside pregnancy were compared. The genetic circumstances underlying glucose metabolism exhibit a similarity between pregnant and non-pregnant populations. While, not all of the T2DM-associated genetic variants are related to pregnant glucose tolerance, such as genes involved in fasting insulin/C-peptide regulation. Some genetic variants may have distinct effects on gestational glucose homeostasis. And certain genes may be particularly involved in this process via specific mechanisms, such as HKDC1, MTNR1B, BACE2, genes encoding cell cycle regulators, adipocyte regulators, inflammatory factors and hepatic factors related to gestational glucose sensing and insulin signaling. However, it is currently difficult to evaluate these associations with quantitative synthesis due to inadequate data, different analytical methods, varied measurements for glycemic traits, controversies in diagnosis of GDM, and unknown ethnicity- and/or sex-related influences on pregnant maternal metabolism. In conclusion, different genetic associations with glycemic traits may exist between pregnant and non-pregnant conditions. Comprehensive research on specific genetic regulation in gestation is necessary. [ABSTRACT FROM AUTHOR]

Several reports have suggested possible role of vitamin D deficiency in the pathogenesis of both type 1 and 2 diabetes. However, there is no agreement on the level of vitamin D requirement for optimum glycemic control. This work evaluated the effect of vitamin D supplementation on oral glucose tolerance (OGT) and insulin sensitivity, with the aim of determining the possible supplementation rate of vitamin D required for optimum glycemic control. Oral glucose tolerance was evaluated in normoglycemic rats, with vitamin D supplementation (VDS) at the rate of 0.07, 0.14, and 0.35 μg/kg orally for 28 days. Oral glucose tolerance (OGT) was evaluated by administration of 2000 mg/kg glucose/rat orally and blood glucose determined at 30, 60, and 120 min post glucose administration. Insulin sensitivity was evaluated in normoglycemic rats fed high fat emulsion (HFE) at the rate of 5 ml/kg/rat for 10 days and VDS was at the rate of 0.04, 0.05, 0.07, and 0.35 μg/kg for 38 days. Insulin (0.05 u/kg) was injected intraperitoneally to each rat, and blood glucose level determined at 5, 30, 60, and 120 min post insulin administration. Blood glucose of VDS rats was significantly (p < 0.05) lower than the vitamin D restricted group at 120 min. Significantly, (p < 0.05) higher OGT was recorded in the VDS groups. Insulin sensitivity (K) values showed inverse dose dependency with higher K values at lower vitamin D doses. Vitamin D supplementation enhanced glucose tolerance and insulin sensitivity at lower doses. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Animal studies have indicated that disturbed diurnal rhythms of clock gene expression in adipose tissue can induce obesity and type 2 diabetes. The importance of the circadian timing system for energy metabolism is well established, but little is known about the diurnal regulation of (clock) gene expression in obese individuals with type 2 diabetes. In this study we aimed to identify key disturbances in the diurnal rhythms of the white adipose tissue transcriptome in obese individuals with type 2 diabetes.Methods: In a case-control design, we included six obese individuals with type 2 diabetes and six healthy, lean control individuals. All participants were provided with three identical meals per day for 3 days at zeitgeber time (ZT, with ZT 0:00 representing the time of lights on) 0:30, 6:00 and 11:30. Four sequential subcutaneous abdominal adipose tissue samples were obtained, on day 2 at ZT 15:30, and on day 3 at ZT 0:15, ZT 5:45 and ZT 11:15. Gene expression was measured using RNA sequencing.Results: The core clock genes showed reduced amplitude oscillations in the individuals with type 2 diabetes compared with the healthy control individuals. Moreover, in individuals with type 2 diabetes, only 1.8% (303 genes) of 16,818 expressed genes showed significant diurnal rhythmicity, compared with 8.4% (1421 genes) in healthy control individuals. Enrichment analysis revealed a loss of rhythm in individuals with type 2 diabetes of canonical metabolic pathways involved in the regulation of lipolysis. Enrichment analysis of genes with an altered mesor in individuals with type 2 diabetes showed decreased activity of the translation initiating pathway 'EIF2 signaling'. Individuals with type 2 diabetes showed a reduced diurnal rhythm in postprandial glucose concentrations.Conclusions/interpretation: Diurnal clock and metabolic gene expression rhythms are decreased in subcutaneous adipose tissue of obese individuals with type 2 diabetes compared with lean control participants. Future investigation is needed to explore potential treatment targets as identified by our study, including clock enhancement and induction of EIF2 signalling.Data availability: The raw sequencing data and supplementary files for rhythmic expression analysis and Ingenuity Pathway Analysis have been deposited in NCBI Gene Expression Omnibus (GEO series accession number GSE104674). [ABSTRACT FROM AUTHOR]

Aims: To determine the prevalence of vitamin B12 deficiency in an urban south Indian population in individuals with different grades of glucose tolerance.Methods: A total of 1500 individuals [900 normal glucose tolerance (NGT), 300 prediabetes and 300 type 2 diabetes (T2DM)] who were not on vitamin B12 supplementation were randomly selected from the Chennai Urban Rural Epidemiological Study (CURES) follow-up study. Anthropometric, clinical and biochemical investigations, which included vitamin B12, insulin, homocysteine, HbA1c and serum lipids, were measured. Vitamin B12 ≤ 191 pg/ml was defined as absolute vitamin B12 deficiency and vitamin B12 > 191 pg/ml and ≤ 350 pg/ml as borderline deficiency.Results: The mean levels of vitamin B12 significantly decreased with increasing degrees of glucose tolerance (NGT 444 ± 368; prediabetes 409 ± 246; T2DM 389 ± 211 pg/ml, p = 0.021). The prevalence of absolute vitamin B12 deficiency was 14.9% while 37.6% had borderline deficiency. The prevalence of absolute vitamin B12 deficiency was significantly higher among individuals with T2DM (18.7%) followed by prediabetes (15%) and NGT(13.7%) [p for trend = 0.05]. The prevalence of vitamin B12 significantly increased with age (p < 0.05) and in those with abdominal obesity (p < 0.001). Men and vegetarians had twice the risk of vitamin B12 deficiency compared to women and non-vegetarians, respectively. Among individuals with NGT, prediabetes and T2DM, vitamin B12 negatively correlated with homocysteine.Conclusion: This study reports that the levels of vitamin B12 decreased with increasing severity of glucose tolerance. [ABSTRACT FROM AUTHOR]

An extraction method was optimized to get a flavonoid-rich ethanol extract from Angelica keiskei leaves (FREE-AK). Trace elements and total flavonoid content of FREE-AK were identified, and the hypoglycemic and hypolipidemic effects of FREE-AK were studied in streptozotocin-induced diabetic mice. For FREE-AK extraction the optimal conditions were 65% ethanol, 45 °C and 15 min, resulting in a total flavonoid content up to 10.18% and K, Mg, Na, and Ca, content of about 36.59, 1.52, 14.51 and 7.486 mg/g, respectively. FREE-AK uptake could cause a marked decrease of fasting blood glucose and a significant improvement on glucose tolerance in diabetic mice. In addition, FREE-AK treatment with a dose of 800 mg/kg b.w. resulted in a reduction in the total triglyceride level (TC) in serum. Results demonstrated the effectiveness of FREE-AK for hypoglycemia and hypolipidemia in streptozotocin-induced mice and FREE-AK may be a potential dietary treatment for type 2 diabetes. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Cre-loxP systems are frequently used in mouse genetics as research tools for studying tissue-specific functions of numerous genes/proteins. However, the expression of Cre recombinase in a tissue-specific manner often produces undesirable changes in mouse biology that can confound data interpretation when using these tools to generate tissue-specific gene knockout mice. Our objective was to characterise the actions of Cre recombinase in skeletal muscle, and we anticipated that skeletal muscle-specific Cre recombinase expression driven by the human α-skeletal actin (HSA) promoter would influence glucose homeostasis.Methods: Eight-week-old HSA-Cre expressing mice and their wild-type littermates were fed a low- or high-fat diet for 12 weeks. Glucose homeostasis (glucose/insulin tolerance testing) and whole-body energy metabolism (indirect calorimetry) were assessed. We also measured circulating insulin levels and the muscle expression of key regulators of energy metabolism.Results: Whereas tamoxifen-treated HSA-Cre mice fed a low-fat diet exhibited no alterations in glucose homeostasis, we observed marked improvements in glucose tolerance in tamoxifen-treated, but not corn-oil-treated, HSA-Cre mice fed a high-fat diet vs their wild-type littermates. Moreover, Cre dissociation from heat shock protein 90 and translocation to the nucleus was only seen following tamoxifen treatment. These improvements in glucose tolerance were not due to improvements in insulin sensitivity/signalling or enhanced energy metabolism, but appeared to stem from increases in circulating insulin.Conclusions/interpretation: The intrinsic glycaemia phenotype in the HSA-Cre mouse necessitates the use of HSA-Cre controls, treated with tamoxifen, when using Cre-loxP models to investigate skeletal muscle-specific gene/protein function and glucose homeostasis. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Paternal high-fat diet prior to mating programmes impaired glucose tolerance in female offspring. We examined whether the metabolic consequences in offspring could be abolished by folate treatment of either the male rats before mating or the corresponding female rats during pregnancy.Methods: Male F0 rats were fed either control diet or high-fat, high-sucrose and high-salt diet (HFSSD), with or without folate, before mating. Male rats were mated with control-diet-fed dams. After mating, the F0 dams were fed control diet with or without folate during pregnancy.Results: Male, but not female offspring of HFSSD-fed founders were heavier than those of control-diet-fed counterparts (p < 0.05 and p = 0.066 in males and females, respectively). Both male and female offspring of HFSSD-fed founders were longer compared with control (p < 0.01 for both sexes). Folate treatment of the pregnant dams abolished the effect of the paternal diet on the offspring’s body length (p ˂ 0.05). Female offspring of HFSSD-fed founders developed impaired glucose tolerance, which was restored by folate treatment of the dams during pregnancy. The beta cell density per pancreatic islet was decreased in offspring of HFSSD-fed rats (−20% in male and −15% in female F1 offspring, p ˂ 0.001 vs controls). Folate treatment significantly increased the beta cell density (4.3% and 3.3% after folate supplementation given to dams and founders, respectively, p ˂ 0.05 vs the offspring of HFSSD-fed male rats). Changes in liver connective tissue of female offspring of HFSSD-fed founders were ameliorated by treatment of dams with folate (p ˂ 0.01). Hepatic Ppara gene expression was upregulated in female offspring only (1.51-fold, p ˂ 0.05) and was restored in the female offspring by folate treatment (p ˂ 0.05). We observed an increase in hepatic Lcn2 and Tmcc2 expression in female offspring born to male rats exposed to an unhealthy diet during spermatogenesis before mating (p ˂ 0.05 vs controls). Folate treatment of the corresponding dams during pregnancy abolished this effect (p ˂ 0.05). Analysis of DNA methylation levels of CpG islands in the Ppara, Lcn2 and Tmcc2 promoter regions revealed that the paternal unhealthy diet induced alterations in the methylation pattern. These patterns were also affected by folate treatment. Total liver DNA methylation was increased by 1.52-fold in female offspring born to male rats on an unhealthy diet prior to mating (p ˂ 0.05). This effect was abolished by folate treatment during pregnancy (p ˂ 0.05 vs the offspring of HFSSD-fed male rats).Conclusions/interpretation: Folate treatment of pregnant dams restores effects on female offspring’s glucose metabolism induced by pre-conception male founder HFSSD. [ABSTRACT FROM AUTHOR]

The pharmacological profile of pitolisant, a histamine H3 receptor antagonist/inverse agonist, indicates that this compound might reduce body weight and metabolic disturbances. Therefore, we studied the influence of pitolisant on body weight, water and sucrose intake as well as metabolic disturbances in the high-fat and high-sugar diet-induced obesity model in mice. To induce obesity, male CD-1 mice were fed a high-fat diet consisting of 40% fat blend for 14 weeks, water and 30% sucrose solution available ad libitum. Glucose tolerance test was performed at the beginning of week 15. Insulin tolerance was tested the day after. At the end of study, plasma levels of triglycerides and cholesterol were determined. Pitolisant at dose of 10 mg/kg bw (ip) was administrated during 14 days, starting from the beginning of week 13. Metformin at dose of 100 mg/kg bw (ip) was used as reference drug. Mice fed with high-fat diet and sucrose solution showed more weight gain throughout the 12-week period of inducing obesity. Animals fed with high-fat diet and treated with pitolisant (for the next 14 days) showed significantly less weight gain than mice from the control group consuming a high-fat feed. In the group treated with pitolisant, glucose levels were significantly lower than glucose levels of control obese mice after glucose load. The plasma triglyceride levels in pitolisant-treated mice were significantly lower compared with those in control obese group. In conclusion, pitolisant has a favorable influence of body weight and improves glucose tolerance and the lipid profile in obese mice. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Low physical activity levels and sedentary behaviour are associated with obesity, insulin resistance and type 2 diabetes. We investigated the effects of a short-term reduction in physical activity with increased sedentary behaviour on metabolic profiles and body composition, comparing the effects in individuals with first-degree relatives with type 2 diabetes (FDR+ve) vs those without (FDR−ve).Methods: Forty-five habitually active participants (16 FDR+ve [10 female, 6 male] and 29 FDR−ve [18 female, 11 male]; age 36 ± 14 years) were assessed at baseline, after 14 days of step reduction and 14 days after resuming normal activity. We determined physical activity (using a SenseWear armband), cardiorespiratory fitness (V̇O2peak), body composition (dual-energy x-ray absorptiometry/magnetic resonance spectroscopy) and multi-organ insulin sensitivity (OGTT) at each time point. Statistical analysis was performed using a two-factor between-groups ANCOVA, with data presented as mean ± SD or (95% CI).Results: There were no significant between-group differences in physical activity either at baseline or following step reduction. During the step-reduction phase, average daily step count decreased by 10,285 steps (95% CI 9389, 11,182; p < 0.001), a reduction of 81 ± 8%, increasing sedentary time by 223 min/day (151, 295; p < 0.001). Pooling data from both groups, following step reduction there was a significant decrease in whole-body insulin sensitivity (Matsuda index) (p < 0.001), muscle insulin sensitivity index (p < 0.001), cardiorespiratory fitness (p = 0.002) and lower limb lean mass (p = 0.004). Further, there was a significant increase in total body fat (p < 0.001), liver fat (p = 0.001) and LDL-cholesterol (p = 0.013), with a borderline significant increase in NEFA AUC during the OGTT (p = 0.050). Four significant between-group differences were apparent: following step reduction, FDR+ve participants accumulated 1.5% more android fat (0.4, 2.6; p = 0.008) and increased triacylglycerol by 0.3 mmol/l (0.1, 0.6; p = 0.044). After resuming normal activity, FDR+ve participants engaged in lower amounts of vigorous activity (p = 0.006) and had lower muscle insulin sensitivity (p = 0.023). All other changes were reversed with no significant between-group differences.Conclusions/interpretation: A short-term reduction in physical activity with increased sedentary behaviour leads to a reversible reduction in multi-organ insulin sensitivity and cardiorespiratory fitness, with concomitant increases in central and liver fat and dyslipidaemia. The effects are broadly similar in FDR+ve and FDR−ve individuals. Public health recommendations promoting physical activity should incorporate advice to avoid periods of sedentary behaviour. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Angiopoietin-like 4 (ANGPTL4) is an important regulator of triacylglycerol metabolism, carrying out this role by inhibiting the enzymes lipoprotein lipase and pancreatic lipase. ANGPTL4 is a potential target for ameliorating cardiometabolic diseases. Although ANGPTL4 has been implicated in obesity, the study of the direct role of ANGPTL4 in diet-induced obesity and related metabolic dysfunction is hampered by the massive acute-phase response and development of lethal chylous ascites and peritonitis in Angptl4−/− mice fed a standard high-fat diet. The aim of this study was to better characterise the role of ANGPTL4 in glucose homeostasis and metabolic dysfunction during obesity.Methods: We chronically fed wild-type (WT) and Angptl4−/− mice a diet rich in unsaturated fatty acids and cholesterol, combined with fructose in drinking water, and studied metabolic function. The role of the gut microbiota was investigated by orally administering a mixture of antibiotics (ampicillin, neomycin, metronidazole). Glucose homeostasis was assessed via i.p. glucose and insulin tolerance tests.Results: Mice lacking ANGPTL4 displayed an increase in body weight gain, visceral adipose tissue mass, visceral adipose tissue lipoprotein lipase activity and visceral adipose tissue inflammation compared with WT mice. However, they also unexpectedly had markedly improved glucose tolerance, which was accompanied by elevated insulin levels. Loss of ANGPTL4 did not affect glucose-stimulated insulin secretion in isolated pancreatic islets. Since the gut microbiota have been suggested to influence insulin secretion, and because ANGPTL4 has been proposed to link the gut microbiota to host metabolism, we hypothesised a potential role of the gut microbiota. Gut microbiota composition was significantly different between Angptl4−/− mice and WT mice. Interestingly, suppression of the gut microbiota using antibiotics largely abolished the differences in glucose tolerance and insulin levels between WT and Angptl4−/− mice.Conclusions/interpretation: Despite increasing visceral fat mass, inactivation of ANGPTL4 improves glucose tolerance, at least partly via a gut microbiota-dependent mechanism. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: The euglycaemic-hyperinsulinaemic clamp is the gold-standard method for measuring insulin sensitivity, but is less suitable for large clinical trials. Thus, several indices have been developed for evaluating insulin sensitivity from the oral glucose tolerance test (OGTT). However, most of them yield values different from those obtained by the clamp method. The aim of this study was to develop a new index to predict clamp-derived insulin sensitivity (M value) from the OGTT-derived oral glucose insulin sensitivity index (OGIS).Methods: We analysed datasets of people that underwent both a clamp and an OGTT or meal test, thereby allowing calculation of both the M value and OGIS. The population was divided into a training and a validation cohort (n = 359 and n = 154, respectively). After a stepwise selection approach, the best model for M value prediction was applied to the validation cohort. This cohort was also divided into subgroups according to glucose tolerance, obesity category and age.Results: The new index, called PREDIcted M (PREDIM), was based on OGIS, BMI, 2 h glucose during OGTT and fasting insulin. Bland-Altman analysis revealed a good relationship between the M value and PREDIM in the validation dataset (only 9 of 154 observations outside limits of agreement). Also, no significant differences were found between the M value and PREDIM (equivalence test: p < 0.0063). Subgroup stratification showed that measured M value and PREDIM have a similar ability to detect intergroup differences (p < 0.02, both M value and PREDIM).Conclusions/interpretation: The new index PREDIM provides excellent prediction of M values from OGTT or meal data, thereby allowing comparison of insulin sensitivity between studies using different tests. [ABSTRACT FROM AUTHOR]

Over the past 50 years, dietary restriction (DR) has been shown to extend the life span of a wide variety of organisms. A hallmark feature of DR is improved glucose homeostasis resulting in increased glucose tolerance and insulin sensitivity of animals ranging from rodents to humans. In this study, we demonstrate the early effects of varying levels of DR on glucose tolerance. Within 10 days of 40% DR, glucose tolerance was significantly improved and by 120 days; 10 and 20% DR also showed enhanced glucose tolerance. All three levels of DR showed reduced adiposity, increased expression of genes involved in fat turnover, and a reduction in the expression for markers of inflammation. Studies have shown that mice fed a DR diet retained metabolic memory in terms of improved glucose tolerance even after DR is discontinued. We show that 40% DR not only has an early effect on glucose tolerance but also maintained it after DR was discontinued for 2 months. Therefore, improvement in glucose tolerance is brought about by all three levels of DR but the metabolic memory is not dose responsive. [ABSTRACT FROM AUTHOR]

C-peptide is the product of proinsulin proteolysis, which is not only a signal molecule but is also able to modulate insulin signaling functions by forming a complex with it. The insulin-sensitive signaling systems in the hypothalamus and other brain areas are among the insulin targets. We hypothesized that, in the systemic deficiency of insulin and C-peptide in type-1 diabetes mellitus (DM) and in severe forms of type-2 DM, an increase in the C-peptide level in the central nervous system (CNS) will improve the central effects of insulin, including its influence on the peripheral metabolism. To verify this, the influence of separate and coadministration of intranasal insulin (II) and C-peptide (IP) on their metabolic parameters and insulin sensitivity in rats with acute and mild type-1 DM induced by streptozotocin at doses of 60 and 35 mg/kg and in rats with neonatal type-2 DM corresponding to severe long-term form of type-2 DM in humans was studied. The treatment of animals with II and IP was carried out for 7 days in daily doses of 20 and 10 µg/rat, respectively. The coadministration of II and IP leading to increased insulin and C-peptide levels in the brain showed the highest effect. In rats with type-1 DM treated with a combination of II and IP, hyperglycemia was decreased and weight loss was prevented. In rats with type-2 DM, coadministration of II and IP led to normalization of glucose homeostasis and increased insulin sensitivity, as shown by the glucose-tolerance and insulin-glucose tolerance tests, as well as to improved lipid metabolism, as demonstrated by a decrease in the atherogenic index. The effectiveness of monotherapy with II was lower than in case of a combination of II and IP, while monotherapy with C-peptide had little effect on the studied indicators. Thus, a simultaneous increase in the insulin and C-peptide levels in the brain upon their deficiency due to diabetic pathology can be considered a promising approach to the restoration of central insulin-dependent regulation of peripheral metabolism and improved glucose utilization in different DM forms. [ABSTRACT FROM AUTHOR]