Effect of Arterial Stiffness and Carotid Intima-Media Thickness Progression on the Risk of Dysglycemia, Insulin Resistance, and Dyslipidemia: a Temporal Causal Longitudinal Study

BACKGROUND

We investigated the temporal causal longitudinal associations of carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness, and carotid intima-media thickness (cIMT) progression with the risk of dysglycemia, insulin resistance, and dyslipidemia.

METHODS

We included 3862, 17.7-year-old, participants from the Avon Longitudinal Study of Parents and Children, followed up for 7 years. cfPWV, cIMT, and fasting plasma samples were repeatedly measured. We computed homeostatic model assessment (HOMA) of insulin resistance and percent pancreatic beta-cell function. Data were analyzed using logistic regression, linear mixed-effect, and cross-lagged structural equation models.

RESULTS

A higher cfPWV at 17.7 years was associated with higher insulin at age 24.5 years (odds ratio, 1.25 [CI, 1.08-1.44]; P=0.003), which slightly attenuated after covariates adjustment. Higher cIMT at 17.7 years was associated with lower insulin (odds ratio, 0.06 [0.01-0.95]; P=0.046) at 24.5 years, after covariate adjustments. In mixed-effect models, the 7-year progression in cfPWV (predictor) was directly associated with the increase in triglyceride (outcome). cIMT progression was associated with the 7-year increase in LDL (low-density lipoprotein), triglyceride, and glucose. In cross-lagged models, higher cfPWV at 17.7 years was associated with higher insulin (β=0.06, SE, 0.12, P=0.014), HOMA of insulin resistance, and HOMA-percent pancreatic beta-cell function at 24.5 years. However, insulin, HOMA of insulin resistance, and HOMA-percent pancreatic beta-cell function at 17.7 years were not associated with cfPWV at 24.5 years. Higher cIMT at 17.7 years was associated with reduced insulin, HOMA of insulin resistance, and HOMA-percent pancreatic beta-cell function at 24.5 years, but not vice versa. Higher glucose at 17.7 years was associated with higher cfPWV and cIMT at 24.5 years only.

CONCLUSIONS

Arterial stiffness in adolescence may be a causal risk factor for hyperinsulinemia and insulin resistance in young adulthood.

Isoform-Specific Role of GSK-3 in High Fat Diet Induced Obesity and Glucose Intolerance

Obesity-associated metabolic disorders are rising to pandemic proportions; hence, there is an urgent need to identify underlying molecular mechanisms. Glycogen synthase kinase-3 (GSK-3) signaling is highly implicated in metabolic diseases. Furthermore, GSK-3 expression and activity are increased in Type 2 diabetes patients. However, the isoform-specific role of GSK-3 in obesity and glucose intolerance is unclear. Pharmacological GSK-3 inhibitors are not isoform-specific, and tissue-specific genetic models are of limited value to predict the clinical outcome of systemic inhibiion. To overcome these limitations, we created novel mouse models of ROSA26CreERT2-driven, tamoxifen-inducible conditional deletion of GSK-3 that allowed us to delete the gene globally in an isoform-specific and temporal manner. Isoform-specific GSK-3 KOs and littermate controls were subjected to a 16-week high-fat diet (HFD) protocol. On an HFD, GSK-3α KO mice had a significantly lower body weight and modest improvement in glucose tolerance compared to their littermate controls. In contrast, GSK-3β-deletion-mediated improved glucose tolerance was evident much earlier in the timeline and extended up to 12 weeks post-HFD. However, this protective effect weakened after chronic HFD (16 weeks) when GSK-3β KO mice had a significantly higher body weight compared to controls. Importantly, GSK-3β KO mice on a control diet maintained significant improvement in glucose tolerance even after 16 weeks. In summary, our novel mouse models allowed us to delineate the isoform-specific role of GSK-3 in obesity and glucose tolerance. From a translational perspective, our findings underscore the importance of maintaining a healthy weight in patients receiving lithium therapy, which is thought to work by GSK-3 inhibition mechanisms.

Persistent high glucose induced EPB41L4A-AS1 inhibits glucose uptake via GCN5 mediating crotonylation and acetylation of histones and non-histones

BACKGROUND

Persistent hyperglycemia decreases the sensitivity of insulin-sensitive organs to insulin, owing to which cells fail to take up and utilize glucose, which exacerbates the progression of type 2 diabetes mellitus (T2DM). lncRNAs' abnormal expression is reported to be associated with the progression of diabetes and plays a significant role in glucose metabolism. Herein, we study the detailed mechanism underlying the functions of lncRNA EPB41L4A-AS1in T2DM.

METHODS

Data from GEO datasets were used to analyze the expression of EPB41L4A-AS1 between insulin resistance or type 2 diabetes patients and the healthy people. Gene expression was evaluated by qRT-PCR and western blotting. Glucose uptake was measured by Glucose Uptake Fluorometric Assay Kit. Glucose tolerance of mice was detected by Intraperitoneal glucose tolerance tests. Cell viability was assessed by CCK-8 assay. The interaction between EPB41L4A-AS1 and GCN5 was explored by RNA immunoprecipitation, RNA pull-down and RNA-FISH combined immunofluorescence. Oxygen consumption rate was tested by Seahorse XF Mito Stress Test.

RESULTS

EPB41L4A-AS1 was abnormally increased in the liver of patients with T2DM and upregulated in the muscle cells of patients with insulin resistance and in T2DM cell models. The upregulation was associated with increased TP53 expression and reduced glucose uptake. Mechanistically, through interaction with GCN5, EPB41L4A-AS1 regulated histone H3K27 crotonylation in the GLUT4 promoter region and nonhistone PGC1β acetylation, which inhibited GLUT4 transcription and suppressed glucose uptake by muscle cells. In contrast, EPB41L4A-AS1 binding to GCN5 enhanced H3K27 and H3K14 acetylation in the TXNIP promoter region, which activated transcription by promoting the recruitment of the transcriptional activator MLXIP. This enhanced GLUT4/2 endocytosis and further suppressed glucose uptake.

CONCLUSION

Our study first showed that the EPB41L4A-AS1/GCN5 complex repressed glucose uptake via targeting GLUT4/2 and TXNIP by regulating histone and nonhistone acetylation or crotonylation. Since a weaker glucose uptake ability is one of the major clinical features of T2DM, the inhibition of EPB41L4A-AS1 expression seems to be a potentially effective strategy for drug development in T2DM treatment.

Recovery of male reproductive endocrine function after ceasing prolonged testosterone undecanoate injections

CONTEXT

The time course of male reproductive hormone recovery after stopping injectable testosterone undecanoate (TU) treatment is not known.

OBJECTIVE

The aim of this study was to investigate the rate, extent, and determinants of reproductive hormone recovery over 12 months after stopping TU injections.

MATERIALS AND METHODS

Men (n = 303) with glucose intolerance but without pathologic hypogonadism who completed a 2-year placebo (P)-controlled randomized clinical trial of TU treatment were recruited for further 12 months while remaining blinded to treatment. Sex steroids (testosterone (T), dihydrotestosterone, oestradiol, oestrone) by liquid chromatography-mass sprectometry, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) by immunoassays and sexual function questionnaires (Psychosexual Diary Questionnaire, International Index of Erectile Function, and short form survey (SF-12)) were measured at entry (3 months after the last injection) and 6, 12, 18, 24, 40, and 52 weeks later.

RESULTS

In the nested cohort of TU-treated men, serum T was initially higher but declined at 12 weeks remaining stable thereafter with serum T and SHBG at 11 and 13%, respectively, lower than P-treated men. Similarly, both questionnaires showed initial carry-over higher scores in T-treated men but after 18 weeks showed no difference between T- and P-treated men. Initially, fully suppressed serum LH and FSH recovered slowly towards the participant's own pre-treatment baseline over 12 months since the last injection.

CONCLUSIONS

After stopping 2 years of 1000 mg injectable TU treatment, full reproductive hormone recovery is slow and progressive over 15 months since the last testosterone injection but may take longer than 12 months to be complete. Persistent proportionate reduction in serum SHBG and T reflects lasting exogenous T effects on hepatic SHBG secretion rather than androgen deficiency.

Mof acetyltransferase inhibition ameliorates glucose intolerance and islet dysfunction of type 2 diabetes via targeting pancreatic α-cells

BACKGROUND

Previously, we reported that Mof was highly expressed in α-cells, and its knockdown led to ameliorated fasting blood glucose (FBG) and glucose tolerance in non-diabetic mice, attributed by reduced total α-cell but enhanced prohormone convertase (PC)1/3-positive α-cell mass. However, how Mof and histone 4 lysine 16 acetylation (H4K16ac) control α-cell and whether Mof inhibition improves glucose handling in type 2 diabetes (T2DM) mice remain unknown.

METHODS

Mof overexpression and chromatin immunoprecipitation sequence (ChIP-seq) based on H4K16ac were applied to determine the effect of Mof on α-cell transcriptional factors and underlying mechanism. Then we administrated mg149 to α-TC1-6 cell line, wild type, db/db and diet-induced obesity (DIO) mice to observe the impact of Mof inhibition in vitro and in vivo. In vitro, western blotting and TUNEL staining were used to examine α-cell apoptosis and function. In vivo, glucose tolerance, hormone levels, islet population, α-cell ratio and the co-staining of glucagon and PC1/3 or PC2 were examined.

RESULTS

Mof activated α-cell-specific transcriptional network. ChIP-seq results indicated that H4K16ac targeted essential genes regulating α-cell differentiation and function. Mof activity inhibition in vitro caused impaired α-cell function and enhanced apoptosis. In vivo, it contributed to ameliorated glucose intolerance and islet dysfunction, characterized by decreased fasting glucagon and elevated post-challenge insulin levels in T2DM mice.

CONCLUSION

Mof regulates α-cell differentiation and function via acetylating H4K16ac and H4K16ac binding to Pax6 and Foxa2 promoters. Mof inhibition may be a potential interventional target for T2DM, which led to decreased α-cell ratio but increased PC1/3-positive α-cells.

Acute and long-term effects of saxagliptin on a set of cardiovascular targets measured at fasting and post-prandially in obese patients with impaired glucose tolerance: A placebo-controlled study

BACKGROUND AND AIMS

Studies of dipeptidyl peptidase inhibitors (DPP4is) report heterogeneous effects on cardiovascular targets in type 2 diabetes. This study aimed to investigate, in patients with impaired glucose tolerance (IGT), whether saxagliptin, a DPP4i, had beneficial cardiovascular effects at fasting and during the post-prandial state.

METHODS AND RESULTS

In this randomized, placebo-controlled, double-blind, single-center pilot exploratory study, we included obese individuals with IGT. Twenty-four individuals (BMI 36.8 ± 4.8 kg/m²) were randomized to receive for 12 weeks either saxagliptin 5 mg a day or placebo. They were explored before and after a standardized breakfast for biological markers; microcirculatory blood flow at baseline and after transcutaneous administration of acetylcholine (Periflux System 5000® PERIMED); post-occlusive digital reactive hyperhemia (Endopat2000®); pulse wave velocity, augmentation index, central pulse pressure and subendocardial viability ratio (Sphygmocor®); cardiac hemodynamic parameters and cardiovascular autonomic nervous system activity (Task force monitor®). The results of all the investigations were similar after breakfast in the two groups at Visit 1 (acute post-prandial effects, after the first tablet) and Visit 2 (long-term post-prandial effects), and at fasting at Visit 1 and 2 (long-term effects, after 12 weeks of treatment). Only at Visit 2 the decrease in cardiac vagal activity occurring after breakfast was more sustained in the saxagliptin group than in the placebo group (interaction between treatment and time effect: p = 0.016).

CONCLUSION

In obese patients with IGT, the effects of saxagliptin on the large set of cardiovascular parameters measured are neutral, except for a more marked post-prandial depression of vagal activity.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01521312.

Prevalence of diabetes related vascular complications in subjects with normal glucose tolerance, prediabetes, newly detected diabetes and known diabetes

AIMS

Varying prevalence of individual diabetes related vascular complications in prediabetes has been reported. However, very few studies have looked at both macrovascular and microvascular complications in prediabetes.

METHODS

Study subjects without any history of diabetes underwent oral glucose tolerance test (OGTT) and were classified as either normal glucose tolerance (NGT), prediabetes (PD), newly detected diabetes mellitus (NDDM) on the basis of American Diabetes Association (ADA) criteria. Age and sex matched known diabetes mellitus (KDM) patients were also recruited. All the participants were subsequently screened for both macrovascular (CAD, CVA,PVD) and microvascular (retinopathy, nephropathy and neuropathy)complications of diabetes.

RESULTS

Prevalence of vascular complications among prediabetes subjects was 11.1% as compared to 1.4% among NGT subjects, 13.9% among NDDM subjects and 23.8% among KDM subjects. There was no significant between complication rates in prediabetes and NDDM group (p = 0.060). The prevalence of macrovascular and microvascular complications among prediabetes subjects was 4.2% and 6.9% while the same in NDDM was 4.2% and 9.7%.

CONCLUSIONS

The proportion of subjects with prediabetes and vascular complications was about half of those with known diabetes and almost similar to those with newly detected diabetes mellitus.

The association between body composition, leptin levels and glucose dysregulation in youth with cystic fibrosis

BACKGROUND

Optimization of nutritional status is recommended in patients with cystic fibrosis (CF) given the association between lower body mass index (BMI) and poor clinical outcomes. However, higher BMI and body fat correlate with glucose impairment and higher leptin levels in the general population. Differences in body composition and leptin levels between the categories of glucose tolerance were assessed in youth with CF and healthy controls.

METHODS

In a cross-sectional study, 59 adolescents and young adults with CF and 15 healthy controls matched by age and gender, underwent body composition analysis using dual energy X-ray absorptiometry (DXA) and a 2-hour oral glucose tolerance test (OGTT). Measures of insulin sensitivity, β-cell insulin secretion and fasting leptin levels were obtained.

RESULTS

Of the participants with CF, 62% were classified as abnormal glucose tolerant and 22% with cystic fibrosis related diabetes (CFRD). Patients with CFRD had a lower fat mass index (FMI) z-score, wt z-score and leptin levels compared to the control group (-1.86 vs. - 0.59, p=0.01; -1.86 vs 0.44, p=<0.001 and 7.9 vs vs. 27.7 µg/L, p=0.01). Leptin correlated positively with FMI z-score, BMI, weight z-score and indices of insulin secretion. FMI z-score correlated positively with higher insulin resistance (HOMA-IR), and lower insulin sensitivity (Matsuda index) (r=0.31; p =0.01 and r=-0.29; p=0.02, respectively) in the CF group.

CONCLUSIONS

This study shows that despite new therapeutic strategies, youth with CF have lower body fat, weight z-score and leptin levels, particularly in subjects with early onset CFRD.

Effect of Sitagliptin on Islet Function in Pancreatic Insufficient Cystic Fibrosis With Abnormal Glucose Tolerance

PURPOSE

Impaired incretin secretion may contribute to the defective insulin secretion and abnormal glucose tolerance (AGT) that associate with worse clinical outcomes in pancreatic insufficient cystic fibrosis (PI-CF). The study objective was to test the hypothesis that dipeptidyl peptidase-4 (DPP-4) inhibitor-induced increases in intact incretin hormone [glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)] concentrations augment insulin secretion and glucagon suppression and lower postprandial glycemia in PI-CF with AGT.

METHODS

26 adults from Children's Hospital of Philadelphia and University of Pennsylvania CF Center with PI-CF and AGT [defined by oral glucose tolerance test glucose (mg/dL): early glucose intolerance (1-h ≥ 155 and 2-h < 140), impaired glucose tolerance (2-h ≥ 140 and < 200 mg/dL), or diabetes (2-h ≥ 200)] were randomized to a 6-month double-blind trial of DPP-4 inhibitor sitagliptin 100 mg daily or matched placebo; 24 completed the trial (n = 12 sitagliptin; n = 12 placebo). Main outcome measures were mixed-meal tolerance test (MMTT) responses for intact GLP-1 and GIP, insulin secretory rates (ISRs), glucagon suppression, and glycemia and glucose-potentiated arginine (GPA) test-derived measures of β- and α-cell function.

RESULTS

Following 6-months of sitagliptin vs placebo, MMTT intact GLP-1 and GIP responses increased (P < 0.001), ISR dynamics improved (P < 0.05), and glucagon suppression was modestly enhanced (P < 0.05) while GPA test responses for glucagon were lower. No improvements in glucose tolerance or β-cell sensitivity to glucose, including for second-phase insulin response, were found.

CONCLUSIONS

In glucose intolerant PI-CF, sitagliptin intervention augmented meal-related incretin responses with improved early insulin secretion and glucagon suppression without affecting postprandial glycemia.

Comparison of islet cell function, insulin sensitivity, and incretin axis between Asian-Indians with either impaired fasting glucose or impaired glucose tolerance, and normal healthy controls

AIMS

The objective of this study was to compare the islet cell function, insulin sensitivity, and incretin axis between Asian-Indian subjects with either impaired fasting glucose (IFG), or impaired glucose tolerance (IGT), and normal glucose tolerance (NGT).

MATERIALS AND METHODS

Prediabetes subjects underwent a mixed meal tolerance test(MMTT) after overnight fasting. Samples for glucose, insulin, glucagon, and glucagon-like peptide-1 (GLP-1) were collected at 0, 30, 60, and 120 min. Insulin secretion sensitivity index -2 (ISSI-2) for beta-cell function and Matsuda index for insulin sensitivity were assessed. Alpha cell function was assessed by measuring the area under the curve (AUC) _0-120 glucagon/AUC_0-120 glucose.

RESULTS

A total of sixty subjects were recruited with 20 in each group. The beta-cell function represented by ISSI-2 was impaired in prediabetes subjects as compared to NGT group (IFG: 2.09 ± 0.44 vs. NGT: 3.04 ± 0.80, P < 0.0001, and IGT: 2.33 ± 0.59 vs. NGT: 3.04 ± 0.80, P = 0.002). Similarly, AUC_0-120 glucagon/AUC_0-120 glucose was also lower in prediabetes group as compared to healthy controls (IFG: 0.41(0.54) vs. NGT: 1.07(0.39), P = 0.003 and IGT: 0.57(0.38) vs. NGT: 1.07(0.39), P = 0.001).

CONCLUSION

Asian-Indian prediabetes subjects have reduced beta-cell function with lesser glucagon secretion during MMTT as compared to normal healthy controls.

Offspring of Obese Dams Exhibit Sex-Differences in Pancreatic Heparan Sulfate Glycosaminoglycans and Islet Insulin Secretion

Offspring of obese mothers suffer higher risks of type 2 diabetes due to increased adiposity and decreased β cell function. To date, the sex-differences in offspring islet insulin secretion during early life has not been evaluated extensively, particularly prior to weaning at postnatal day 21 (P21). To determine the role of maternal obesity on offspring islet insulin secretion, C57BL/6J female dams were fed chow or western diet from 4 weeks prior to mating to induce maternal obesity. First, offspring of chow-fed and obese dams were evaluated on postnatal day 21 (P21) prior to weaning for body composition, glucose and insulin tolerance, and islet phasic insulin-secretion. Compared to same-sex controls, both male and female P21 offspring born to obese dams (MatOb) had higher body adiposity and exhibited sex-specific differences in glucose tolerance and insulin secretion. The male MatOb offspring developed the highest extent of glucose intolerance and lowest glucose-induced insulin secretion. In contrast, P21 female offspring of obese dams had unimpaired insulin secretion. Using SAX-HPLC, we found that male MatOb had a decrease in pancreatic heparan sulfate glycosaminoglycan, which is a macromolecule critical for islet health. Notably, 8-weeks-old offspring of obese dams continued to exhibit a similar pattern of sex-differences in glucose intolerance and decreased islet insulin secretion. Overall, our study suggests that maternal obesity induces sex-specific changes to pancreatic HSG in offspring and a lasting effect on offspring insulin secretion, leading to the sex-differences in glucose intolerance.

Soluble guanylate cyclase chronic stimulation effects on cardiovascular reactivity in cafeteria diet-induced rat model of metabolic syndrome

Metabolic syndrome is linked to an increased risk of cardiovascular complications by a mechanism involving mainly decreased nitric oxide (NO) bioavailability and impaired NO-soluble guanylate cyclase (sGC)- cyclic guanosine monophosphate (cGMP) signalling (NO-sGC-cGMP). To further develop this scientific point, this study aimed to investigate the effects of long-term treatment with BAY 41-2272 (a sGC stimulator) on cardiovascular reactivity of spontaneously hypertensive rats (SHR) as a model of metabolic syndrome. SHR were randomly divided into 3 groups: control group, cafeteria diet (CD)-fed group and CD-fed group treated daily with BAY 41-2272 (5 mg/kg) by gastric gavage for 12 weeks. In vivo measurements of body weight, abdominal circumference, blood pressure and glucose tolerance test were performed. At the end of the feeding period, ex vivo cumulative concentration-response curves were performed on isolated perfused heart (isoproterenol (0.1 nM - 1 μM)) and thoracic aorta (phenylephrine (1 nM-10 μM), acetylcholine (1 nM-10 μM), and sodium nitroprusside (SNP) (0.1 nM-0.1 μM)). We showed that chronic CD feeding induced abdominal obesity, hypertriglyceridemia, glucose intolerance and exacerbated arterial hypertension in SHR. Compared to control group, CD-fed group showed a decrease in β-adrenoceptor-induced cardiac inotropy, in coronary perfusion pressure and in aortic contraction to phenylephrine. While relaxing effects of acetylcholine and SNP were unchanged. BAY 41-2272 long-term treatment markedly prevented arterial hypertension development and glucose intolerance, enhanced the α1-adrenoceptor-induced vasoconstriction, and restored cardiac inotropy and coronary vasodilation. These findings suggest that BAY 41-2272 may be a potential novel drug for preventing metabolic and cardiovascular complications of metabolic syndrome.

Sex-specific effects of ketogenic diet after pre-exposure to a high-fat, high-sugar diet in rats

BACKGROUND AND AIMS

The objectives were to evaluate the relationship between ketogenic diets, the ketone body beta-hydroxybutyrate (BHB), parameters known to increase risk for cardiovascular and metabolic diseases in both sexes, using a pre-clinical model of obesity.

METHODS AND RESULTS

Rats had access to a diet high in fat and sugar (HFS) for 12 weeks. After HFS, they switched to chow (HFS-CH) or ketogenic diet (HFS-KD) for 3 weeks to model a dietary intervention. Body weight, adiposity, and food intake were measured. Glucose tolerance and corticosterone response to stress were measured after HFS, then again after the intervention. Both sexes increased body weight, food intake, and adiposity compared to control (CTL) while on HFS. HFS females showed impaired glucose tolerance. HFS males developed a dampened corticosterone to stress, whereas HFS females developed an exacerbated response. The effects of HFS on adiposity and corticosterone were reversed in HFS-CH males. These same improvements were observed in HFS-CH females, although they still had impaired glucose tolerance. HFS-KD males showed some improvements, however, they still had higher body weight and adiposity than CTL. The same pattern was observed in females. These beneficial effects of KD correlated with plasma BHB levels in females but not in males.

CONCLUSIONS

These data model effects reported in clinical literature and serve as a valuable translational tool to further test causal mechanisms that lead to desirable outcomes of KD. These sex-specific relationships are important, as KD could potentially affect endocrine mechanisms differently in males and females.

Proper mTORC1 Activity Is Required for Glucose Sensing and Early Adaptation in Human Pancreatic β Cells

CONTEXT

The mechanistic target of rapamycin complex I (mTORC1) is crucial for β-cell identity and function in rodents. However, its possible relevance to the physiopathology of diabetes in humans remains unclear.

OBJECTIVE

This work aimed to understand the participation of mTORC1 in human β cells in prediabetes and diabetes.

DESIGN

We evaluated the PS6 immunofluorescence intensity in islets of pancreatic sections from 12 nondiabetic (ND), 11 impaired fasting glucose (IFG), and 11 glycemic-controlled type 2 diabetic (T2D) individuals. We also assessed the dynamic change of mTORC1 activity in β cells of db/db mice with new-onset diabetes.

RESULTS

There exists intercellular heterogeneity of mTORC1 activities in human islets. Islet mTORC1 activity was independently and positively correlated with FBG in ND, but not in IFG and T2D. Moreover, we did not detect significant change in mTORC1 activities between T2D and ND. Of note, the islet mTORC1 activities were significantly higher in IFG than in ND. We further stratified IFG individuals according to their islet PS6 levels and found that IFG-PS6high exhibited remarkably higher urocortin3 and glucose transporter 2 expression in their β cells compared to IFG-PS6low. Consistently, we also detected a significant increase in mTORC1 activities in prediabetic db/db mice compared to nondiabetic littermates. Interestingly, mTORC1 activities determined β-cell adaptation or failure in db/db mice: A strong negative correlation was found between islet mTORC1 activities and fasting glucose levels in db/db mice during their diabetes progression.

CONCLUSIONS

Our finding highlights a dynamic islet mTORC1 response in β-cell adaption/failure in human T2D.

Sex-dimorphic genetic effects and novel loci for fasting glucose and insulin variability

Differences between sexes contribute to variation in the levels of fasting glucose and insulin. Epidemiological studies established a higher prevalence of impaired fasting glucose in men and impaired glucose tolerance in women, however, the genetic component underlying this phenomenon is not established. We assess sex-dimorphic (73,089/50,404 women and 67,506/47,806 men) and sex-combined (151,188/105,056 individuals) fasting glucose/fasting insulin genetic effects via genome-wide association study meta-analyses in individuals of European descent without diabetes. Here we report sex dimorphism in allelic effects on fasting insulin at IRS1 and ZNF12 loci, the latter showing higher RNA expression in whole blood in women compared to men. We also observe sex-homogeneous effects on fasting glucose at seven novel loci. Fasting insulin in women shows stronger genetic correlations than in men with waist-to-hip ratio and anorexia nervosa. Furthermore, waist-to-hip ratio is causally related to insulin resistance in women, but not in men. These results position dissection of metabolic and glycemic health sex dimorphism as a steppingstone for understanding differences in genetic effects between women and men in related phenotypes.

Association of glucose metabolism and retinopathy signs in non-diabetic individuals in midlife-The Northern Finland Birth Cohort 1966 study

Diabetic retinopathy is a microvascular complication of hyperglycaemia. Little is known about the association of glucose metabolism and retinopathy signs in the non-diabetic middle-aged population. We studied prevalence of retinopathy in a subsample of Northern Finland Birth Cohort study (NFBC1966) of 1809 subjects, at 47 years of age, without previously diagnosed type 2 diabetes and/or blood pressure-lowering medication. All participants underwent clinical evaluations including an oral glucose tolerance test (glucose and insulin values measured at 0, 30, 60 and 120 min) and HbA1c. The retinopathy signs were diagnosed by fundus photographs and classified according to the Eurodiab classification scheme. The overall prevalence of newly diagnosed retinopathy was 1.4%. The retinopathy signs were significantly associated with increased 30 min, 1-h and 2-h glucose levels and 2-h insulin level in an OGTT. After adjustment with systolic blood pressure, only 30 min glucose, 1-h glucose and 2-h insulin levels were associated with retinopathy signs. Our findings show the potential role of 30 min and 1-h post-load glucose and 2-h insulin levels as risk factors for retinopathy lesions among the participants without previously diagnosed diabetes or hypertensive medication.

Deconstructing circadian disruption: Assessing the contribution of reduced peripheral oscillator amplitude on obesity and glucose intolerance in mice

Disturbing the circadian regulation of physiology by disruption of the rhythmic environment is associated with adverse health outcomes but the underlying mechanisms are unknown. Here, the response of central and peripheral circadian clocks to an advance or delay of the light-dark cycle was determined in mice. This identified transient damping of peripheral clocks as a consequence of an advanced light-dark cycle. Similar depression of peripheral rhythm amplitude was observed in mice exposed to repeated phase shifts. To assess the metabolic consequences of such peripheral amplitude depression in isolation, temporally chimeric mice lacking a functional central clock (Vgat-Cre⁺ Bmal1^fl/fl ) were housed in the absence of environmental rhythmicity. In vivo PER2::LUC bioluminescence imaging of anesthetized and freely moving mice revealed that this resulted in a state of peripheral amplitude depression, similar in severity to that observed transiently following an advance of the light-dark cycle. Surprisingly, our mice did not show alterations in body mass or glucose tolerance in males or females on regular or high-fat diets. Overall, our results identify transient damping of peripheral rhythm amplitude as a consequence of exposure to an advanced light-dark cycle but chronic damping of peripheral clocks in isolation is insufficient to induce adverse metabolic outcomes in mice.

Altered pancreas remodeling following glucose intolerance in pregnancy in mice

Gestational diabetes mellitus increases the risk of dysglycemia postpartum, in part, due to pancreatic β-cell dysfunction. However, no histological evidence exists comparing endocrine pancreas after healthy and glucose-intolerant pregnancies. This study sought to address this knowledge gap, in addition to exploring the contribution of an inflammatory environment to changes in endocrine pancreas after parturition. We used a previously established mouse model of gestational glucose intolerance induced by dietary low protein insult from conception until weaning. Pancreas and adipose samples were collected at 7, 30 and 90 days postpartum for histomorphometric and cytokine analyses, respectively. Glucose tolerance tests were performed prior to euthanasia and blood was collected via cardiac puncture. Pregnant female mice born to dams fed a low protein diet previously shown to develop glucose intolerance at late gestation relative to controls continued to be glucose intolerant until 1 month postpartum. However, glucose tolerance normalized by 3 months postpartum. Glucose intolerance at 7 days postpartum was associated with lower beta- and alpha-cell fractional areas and higher adipose levels of pro-inflammatory cytokine, interleukin-6. By 3 months postpartum, a compensatory increase in the number of small islets and a higher insulin to glucagon ratio likely enabled euglycemia to be attained in the previously glucose-intolerant mice. The results show that impairments in endocrine pancreas compensation in hyperglycemic pregnancy persist after parturition and contribute to prolonged glucose intolerance. These impairments may increase the susceptibility to development of future type 2 diabetes.

Risk factors during the early postpartum period for type 2 diabetes mellitus in women with gestational diabetes

For women with gestational diabetes mellitus (GDM), the evaluation of glucose tolerance (GT) in the early postpartum period is universally recommended. Nevertheless, few studies have evaluated the risk factors for T2DM on the basis of GT data obtained during the early postpartum period. We aimed to identify the risk factors for type 2 diabetes mellitus (T2DM) by evaluating GT in the first 12 weeks postpartum (12wPP) in women with GDM and to categorize the risk using a combination of the principal risk factors. This retrospective multicenter observational study included 399 East Asian women with GDM who underwent a 75-g oral glucose tolerance test (OGTT) within 12wPP, which was repeated annually or biennially and used to identify the postpartum development of T2DM. Forty-three women (10.8%) developed T2DM during a median follow-up period of 789 ± 477 days. The independent risk factors for T2DM were pre-pregnancy obesity (BMI ≥25 kg/m²), early postpartum impairment in glucose tolerance (IGT), and an early postpartum glycated hemoglobin (HbA1c) ≥5.7%. The odds ratios (95% confidence intervals) for T2DM were 3.2 (1.3-7.8) in women with either early postpartum IGT or pre-pregnancy obesity, 9.2 (3.0-28.3) in those with early postpartum IGT, pre-pregnancy obesity, and HbA1c <5.7%, and 51.4 (16.1-163.9) in those with early postpartum IGT, pre-pregnancy obesity, and HbA1c ≥5.7%, compared with those without obesity or IGT. T2DM risk in East Asian women with GDM should be stratified according to pre-pregnancy obesity and early postpartum IGT, and these patients should be followed up and receive appropriate care for their risk category.

1,5-Anhydroglucitol × glycated hemoglobin A1c/100 as a potential biomarker for islet β-cell function among patients with type 2 diabetes

AIMS

This study aimed to explore the level of and changes in the 1,5-anhydroglucitol × glycated hemoglobin A_1c/100 (AH index, AHI) associated with different glucose metabolism statuses and to evaluate the islet function and insulin sensitivity of patients with type 2 diabetes (T2DM) with different AHI levels.

METHODS

Of the 3562 subjects enrolled in this study, 1697 had T2DM. The disposition index (DI) was the product of islet secretion function and insulin sensitivity-related indexes.

RESULTS

The mean AHI level was 1.0 (0.7-1.3) in the general population, while the mean AHI level in the T2DM group was 0.8 (0.5-1.2), which was significantly lower than that in the impaired glucose regulation and normal glucose tolerance group (both 1.2 (0.9-1.5), both P < 0.01). We further divided patients with T2DM into four subgroups according to the quartile of AHI. The results showed that with the increase in AHI level, the homeostasis model assessment of insulin resistance (HOMA-IR) decreased, while HOMA-β, insulin generation index, insulin sensitivity index, and DI increased (all P_{for trend} < 0.01). Multivariate logistic regression showed that the odds ratios for a low DI for increasing levels of AHI were 1.00, 0.22 (0.16-0.29), 0.16 (0.11-0.22), and 0.09 (0.06-0.13), showing a decreasing trend (P_{for trend} < 0.05).

CONCLUSION

The AHI could reflect the variation in glycemic disorder and the function of islet β cells. The lower the AHI, the worse the glycemic disorder, as well as the islet β-cell function.

Weight Loss Improves β-Cell Function in People With Severe Obesity and Impaired Fasting Glucose: A Window of Opportunity

BACKGROUND

In people with obesity, β-cell function may adapt to insulin resistance. We describe β-cell function in people with severe obesity and normal fasting glucose (NFG), impaired fasting glucose (IFG), and type 2 diabetes (T2DM), as assessed before, 3 to 6 months after, and 2 years after medical weight loss to describe its effects on insulin sensitivity, insulin secretion, and β-cell function.

METHODS

Fifty-eight participants with body mass index (BMI) ≥ 35 kg/m2 (14 with NFG, 24 with IFG, and 20 with T2DM) and 13 normal weight participants with NFG underwent mixed meal tolerance tests to estimate insulin sensitivity (S[I]), insulin secretion (Φ), and β-cell function assessed as model-based Φ adjusted for S(I). All 58 obese participants were restudied at 3 to 6 months and 27 were restudied at 2 years.

RESULTS

At 3 to 6 months, after a 20-kg weight loss and a decrease in BMI of 6 kg/m2, S(I) improved in all obese participants, Φ decreased in obese participants with NFG and IFG and tended to decrease in obese participants with T2DM, and β-cell function improved in obese participants with NFG and tended to improve in obese participants with IFG. At 2 years, β-cell function deteriorated in participants with NFG and T2DM but remained significantly better in participants with IFG compared to baseline.

CONCLUSIONS

Short-term weight loss improves β-cell function in participants with NFG and IFG, but β-cell function tends to deteriorate over 2 years. In participants with IFG, weight loss improves longer-term β-cell function relative to baseline and likely relative to no intervention, suggesting that obese people with IFG are a subpopulation whose β-cell function is most likely to benefit from weight loss.

Circulating myokine levels in different stages of glucose intolerance

Type 2 diabetes is the fastest growing metabolic disease in the world. Recently, muscle is considered an endocrine organ which secretes various peptides that play an important role in insulin resistance and metabolic syndrome. We assessed 4 different myokines, irisin, interleukin-13 (IL-13), follistatin-related protein-1 (FSTL-1), and fractalkine, in normal, prediabetes, and diabetes patients.A total of 126 participants who visited Gangnam Severance Hospital were enrolled and divided into normal, prediabetes, and diabetes groups based on oral glucose tolerance test and hemoglobin a1c. A cross-sectional study was conducted to measure and compare serum levels of irisin, IL-13, FSTL-1, and fractalkine among the groups.Irisin level showed a tendency to increase in prediabetes group compared to normal group (P < .1) but showed a significant decrease when comparing diabetes from prediabetes group (P < .001). IL-13 decreased in diabetes group compared to prediabetes and normal group (P < .001, P < .05, respectively). FSTL-1 of diabetes group was lower than that of prediabetes group (P < .05), and fractalkine was higher in diabetes group compared to that of prediabetes and normal group (P < .01, P < .01, respectively).Irisin, IL-13, and FSTL-1 levels were reduced in diabetes group compared to normal or prediabetes group while fractalkine showed a progressive increase from normal to diabetes group. Further studies are warranted to study the roles of various myokine in diabetes through a larger prospective study.

Increased Susceptibility to Obesity and Glucose Intolerance in Adult Female Rats Programmed by High-Protein Diet during Gestation, But Not during Lactation

Fetal and early postnatal nutritional environments contribute to lifelong health. High-protein (HP) intake in early life can increase obesity risk in response to specific feeding conditions after weaning. This study investigated the effects of a maternal HP diet during pregnancy and/or lactation on the metabolic health of offspring. Three groups of dams received a normal-protein (NP, 20E% proteins) diet during gestation and lactation (Control group), an HP diet (55E% proteins) during gestation (HPgest group), or an HP diet during lactation (HPlact group). From weaning until 10 weeks, female pups were exposed to the NP, the HP or the western (W) diet. HPgest pups had more adipocytes (p = 0.009), more subcutaneous adipose tissue (p = 0.04) and increased expression of genes involved in liver fatty acid synthesis at 10 weeks (p < 0.05). HPgest rats also showed higher food intake and adiposity under the W diet compared to the Control and HPlact rats (p ≤ 0.04). The post-weaning HP diet reduced weight (p < 0.0001), food intake (p < 0.0001), adiposity (p < 0.0001) and glucose tolerance (p < 0.0001) compared to the NP and W diets; this effect was enhanced in the HPgest group (p = 0.04). These results show that a maternal HP diet during gestation, but not lactation, leads to a higher susceptibility to obesity and glucose intolerance in female offspring.

Transgenerational Inheritance of Reproductive and Metabolic Phenotypes in PCOS Rats

Androgen exposure of female fetuses could be an important factor in the development of polycystic ovary syndrome (PCOS) in subsequent generations. The present study aimed to investigate the transgenerational effects of PCOS on the growth, reproduction, and metabolism of the first- and second-generation offspring in rats. Female F0 rats received excessive dehydroepiandrosterone (DHEA) exposure to establish PCOS or the same amount of vehicle as controls. These F0 females were crossed with normal males to obtain control (C) and DHEA (D) F1 offspring, whereas F2 offspring were obtained by inter-crossing between F1 rats for 4 groups: (1) C♂-C♀; (2) D♂-C♀; (3) C♂-D♀ and (4) D♂-D♀. Compared with control groups, F1 and F2 offspring with ancestral DHEA exposure showed higher body weight with increasing age. In addition, female F1 and F2 offspring with ancestral DHEA exposure exhibited PCOS-like reproductive and metabolic phenotypes, including disrupted estrous cycles and polycystic ovaries, as well as increased serum levels of testosterone, impaired glucose tolerance and widespread metabolic abnormalities. Male offspring with ancestral DHEA exposure exhibited lower quality of sperms. These findings confirm the negative effects of excessive androgen exposure of female fetuses on subsequent generations.

Endothelial and Autonomic Dysfunction at Early Stages of Glucose Intolerance and in Metabolic Syndrome

This study evaluated sE-selectin, Endothelin-1, and cardiovascular autonomic neuropathy (CAN) at early stages of glucose intolerance and in metabolic syndrome (MetS). A total of 87 subjects - 39 males, of mean age 45.7±11.6 years and mean BMI 31.4±6.6 kg/m², divided according to glucose tolerance and the presence of MetS were enrolled. Glucose tolerance was studied during OGTT. Anthropometric indices, blood pressure, HbA1c, lipids, hsCRP, sE-selectin, Endothelin-1, and immunoreactive insulin were measured. Body composition was assessed by a bioimpedance method (InBody 720, BioSpace). Tissue AGEs accumulation was evaluated by skin autofluorescence (AGE-Reader, DiagnOpticsTM). CAN was assessed by ANX-3.0 technology. In the groups, according to glucose tolerance, the prevalence of CAN was 5.7% in normal glucose tolerance (NGT), 8.6% in prediabetes, and 23.5% in newly diagnosed type 2 diabetes (NDD). In the groups, according to the presence of MetS, the prevalence of CAN was 12.3% in those with MetS and 4.8% in those without MetS. Parasympathetic activity was diminished at rest (p=0.048, 0.015, respectively) in NDD as compared to prediabetes and NGT; and there was a numerically elevated heart rate at rest in NDD in comparison to NGT. There was a negative correlation between parasympathetic tone and waist circumference, BMI, and visceral and total fat. There was no difference in the measured endothelial function markers in the groups according to glucose tolerance and MetS. sE-selectin correlated with HOMA-IR (r=0.275, p=0.048). No association between Endothelin-1 levels and assessed metabolic parameters was observed. There is a high prevalence of CAN at early stages of glucose intolerance and in MetS, due to decreased parasympathetic activity. Slight elevation of glycemia and MetS probably do not affect endothelial function, since sE-selectin seems to be related to insulin resistance.

Differential metabolic and multi-tissue transcriptomic responses to fructose consumption among genetically diverse mice

Understanding how individuals react differently to the same treatment is a major concern in precision medicine. Metabolic challenges such as the one posed by high fructose intake are important determinants of disease mechanisms. We embarked on studies to determine how fructose affects differential metabolic dysfunctions across genetically dissimilar mice, namely, C57BL/6 J (B6), DBA/2 J (DBA) and FVB/NJ (FVB), by integrating physiological and gene regulatory mechanisms. We report that fructose has strain-specific effects, involving tissue-specific gene regulatory cascades in hypothalamus, liver, and white adipose tissues. DBA mice showed the largest numbers of genes associated with adiposity, congruent with their highest susceptibility to adiposity gain and glucose intolerance across the three tissues. In contrast, B6 and FVB mainly exhibited cholesterol phenotypes, accompanying the largest number of adipose genes correlating with total cholesterol in B6, and liver genes correlating with LDL in FVB mice. Tissue-specific network modeling predicted strain-and tissue-specific regulators such as Fgf21 (DBA) and Lss (B6), which were subsequently validated in primary hepatocytes. Strain-specific fructose-responsive genes revealed susceptibility for human diseases such that genes in liver and adipose tissue in DBA showed strong enrichment for human type 2 diabetes and obesity traits. Liver and adipose genes in FVB were mostly related to lipid traits, and liver and adipose genes in B6 showed relevance to most cardiometabolic traits tested. Our results show that fructose induces gene regulatory pathways that are tissue specific and dependent on the genetic make-up, which may underlie interindividual variability in cardiometabolic responses to high fructose consumption.

Longitudinal Changes in Fasting and Glucose-Stimulated GLP-1 and GIP in Healthy Older Subjects

CONTEXT

It is not known whether glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) levels correlate within individuals, nor whether levels change with age. Previous studies have all been cross-sectional in design.

OBJECTIVE

To evaluate longitudinal changes in fasting and glucose-stimulated incretin hormone concentrations in healthy older subjects.

PATIENTS AND DESIGN

Forty-one healthy older subjects had measurements of plasma GLP-1 and GIP while fasting and after a 75-g oral glucose load on two occasions separated by 5.9 ± 0.1 years [mean age at the initial study: 71.2 ± 3.8 (SD) years]. Breath samples were collected to calculate the gastric 50% emptying time (T50).

RESULTS

For GLP-1, both fasting concentrations (P < 0.001) and area under the curve 0 to 120 minutes (P = 0.001) were decreased at followup. Fasting GIP was also lower (P = 0.03) at follow up, but there was no change in the area under the curve 0 to 120 minutes (P = 0.26). The gastric emptying T50 was slower at followup (P = 0.008). Neither the change in T50 nor the body mass index at the initial study was a determinant of the change in incretin responses. Between the two study days, fasting GIP (r = 0.72, P < 0.001) correlated well, but not fasting GLP-1 (r = 0.23, P = 0.18). However, both glucose-stimulated GLP-1 (r = 0.50, P = 0.002) and GIP (r = 0.60, P < 0.001) showed correlations between the initial and follow-up studies.

CONCLUSIONS

Fasting GIP and glucose-stimulated GLP-1 and GIP concentrations correlate within individuals over a follow-up period of ∼5.9 years. Aging is associated with reductions in fasting GLP-1 and GIP, and glucose-stimulated GLP-1, which may predispose to the development of glucose intolerance and type 2 diabetes.

A role for placental kisspeptin in β cell adaptation to pregnancy

During pregnancy the maternal pancreatic islets of Langerhans undergo adaptive changes to compensate for gestational insulin resistance. Kisspeptin has been shown to stimulate insulin release, through its receptor, GPR54. The placenta releases high levels of kisspeptin into the maternal circulation, suggesting a role in modulating the islet adaptation to pregnancy. In the present study we show that pharmacological blockade of endogenous kisspeptin in pregnant mice resulted in impaired glucose homeostasis. This glucose intolerance was due to a reduced insulin response to glucose as opposed to any effect on insulin sensitivity. A β cell–specific GPR54-knockdown mouse line was found to exhibit glucose intolerance during pregnancy, with no phenotype observed outside of pregnancy. Furthermore, in pregnant women circulating kisspeptin levels significantly correlated with insulin responses to oral glucose challenge and were significantly lower in women with gestational diabetes (GDM) compared with those without GDM. Thus, kisspeptin represents a placental signal that plays a physiological role in the islet adaptation to pregnancy, maintaining maternal glucose homeostasis by acting through the β cell GPR54 receptor. Our data suggest reduced placental kisspeptin production, with consequent impaired kisspeptin-dependent β cell compensation, may be a factor in the development of GDM in humans.

Placental kisspeptin regulates islet adaptation to pregnancy that is necessary for preventing gestational diabetes in mice and humans.

Alterations in hearing function of patients with glucose disorders

OBJECTIVE

To study the prevalence of hearing impairment in patients with various glucose disorders.

PATIENTS AND METHODS

A total of 499 individuals were studied, 51 patients with type 1 (TIDM), 188 patients with type 2 diabetes mellitus (T2DM), 39 patients with impaired fasting glucose (IFG), and 221 controls. Measurements were performed, blood was drawn, and a relevant questionnaire was completed. Ηearing function was assessed by pure-tone audiometry (PTA) and distortion product otoacustic emissions (DPOAEs).

RESULTS

Patients with impaired glucose metabolism (IGM: T2DM or IFG) compared to controls had a higher percentage of abnormal PTA and DPOAEs for both the right (70.2 vs. 56.9% and 40.4 vs. 24.2%, respectively, p < 0.001) and the left (74.1 vs. 59.3% and 47.5 vs. 25.4%, respectively, p < 0.001) ear. Patients with TIDM had similar levels for the left ear (54.9 vs. 59.3% and 27.5 vs. 25.4%, respectively, p > 0.05) and lower levels for the right ear (35.3 vs. 56.9% and 13.7 vs. 24.2%, respectively, p < 0.001 and p = 0.044) percentages of abnormal PTA and DPOAEs compared to controls. Logistic regression analysis indicated that independent parameters for abnormal DPOAEs in one or both ears are age, male gender, exposure to noisy environments, and the presence of IGM.

CONCLUSIONS

Hearing impairment was more prevalent in patients with IGM compared to healthy controls, as assessed by PTA and DPOAEs. Age, male gender, and exposure to noise are other factors that can independently affect hearing ability. Physicians should bear in mind possible defects in hearing ability when dealing with such patients.

Decrease of FGF19 contributes to the increase of fasting glucose in human in an insulin-independent manner

PURPOSE

The ileum-derived fibroblast growth factor 19 (FGF19) plays key roles in hepatic glucose homeostasis in animals in an insulin-independent manner. Here, we analyzed the association of FGF19 with glucose effectiveness (GE, the insulin-independent glucose regulation), as well as hepatic glucose production (HGP) in Chinese subjects.

METHODS

GE was measured by frequently sampled intravenous glucose tolerance test (FSIVGTT) in normal glucose tolerance (NGT), isolated-impaired glucose tolerance (I-IGT), and isolated-impaired fasting glucose (I-IFG) subjects. The oral glucose tolerance test-derived surrogate of GE (oGE) was determined in NGT, I-IFG, combined glucose intolerance (CGI), and type 2 diabetes (T2DM) subjects. HGP was assessed by labeled ([3-³H]-glucose) hyperinsulinemic-euglycemic clamp in NGT subjects. Insulin secretion and sensitivity were calculated by the hyperglycemic and hyperinsulinemic-euglycemic clamps in a subgroup of NGT, I-IGT, and I-IFG subjects. Serum FGF19 levels were determined by ELISA.

RESULTS

FGF19 positively correlated with GE (r = 0.29, P = 0.004) as determined by FSIVGTT. The result was further confirmed by oGE (r = 0.261, P < 0.001). FGF19 was negatively associated with FPG (r = - 0.228, P = 0.025), but the association no longer existed after adjusting for GE (r = - 0.177, P = 0.086). FGF19 was negatively associated with basal HGP (r = - 0.697, P = 0.006). However, the correlation between FGF19 and insulin secretion and sensitivity were not found.

CONCLUSIONS

FGF19 levels are associated positively with GE and negatively with HGP. The increase of FPG in human is at least partially due to the decrease of FGF19 in an insulin-independent manner.

Effects of Urinary Kallidinogenase on NIHSS score, mRS score, and fasting glucose levels in acute ischemic stroke patients with abnormal glucose metabolism: A prospective cohort study

Urinary kallidinogenase may assist recovery acute ischemic stroke. This study evaluated the effect of urinary kallidinogenase on National Institute of Health Stroke Scale (NIHSS) score, modified Rankin scale (mRS) score, and fasting glucose levels in patients with acute ischemic stroke (AIS) combined with diabetes mellitus and impaired fasting glucose.Patients with AIS and abnormal glucose metabolism were enrolled in this prospective cohort study and divided into 2 groups. The human urinary kallidinogenase (HUK) group were treated with urinary kallidinogenase and standard treatment; the control group received standard treatment. NIHSS scores, mRS scores, and fasting blood glucose were evaluated and compared.A total of 113 patients were included: 58 in the HUK group and 55 in the control group. NIHSS scores decreased with treatment in both groups (time effect P < .05), but were lower in the HUK group (main effect P = .026). The mRS score decreased in both groups from 10 until 90 days after treatment (time effect P < .05); the 2 groups were similar (main effect, P = .130). Blood glucose levels decreased in both groups 10 days after treatment (time effect, P < .05), but there was no significant treatment effect (main effect, P = .635). Multivariate analysis showed blood uric acid >420 μmol/L (odds ratio [OR]: 0.053, 95% confidence interval [CI]: 0.008-0.350; P = .002) and application of HUK (OR: 0.217, 95% CI: 0.049-0.954; P = .043) were associated with 90% NIHSS recovery. Baseline NIHSS score was independently associated with poor curative effect.Urinary kallidinogenase with conventional therapy significantly improved NIHSS scores in patients with AIS. Urinary kallidinogenase also showed a trend toward lower fasting blood glucose levels, although the level did not reach significance.

Plasma glucose concentration 60 min post oral glucose load and risk of type 2 diabetes and cardiovascular disease: Pathophysiological implications

AIM

The aim of this study was to gain insight into the pathophysiological significance of elevated plasma glucose concentrations (mmol/L) 60 min post oral glucose load in apparently healthy individuals.

METHODS

Comparison of resistance to insulin action and associated cardio-metabolic risk factors in 490 apparently healthy persons, subdivided into those with a plasma glucose concentration 60 min following a 75-g oral glucose challenge of <8.6 versus ⩾8.6.

RESULTS

Insulin resistance was significantly greater in persons with normal glucose tolerance whose 60-min glucose concentration was ⩾8.6, associated with higher blood pressure, plasma concentrations of glucose, insulin, triglyceride and lower high-density lipoprotein cholesterol concentrations. Similar differences were seen in persons with impaired fasting glucose, but not in those with impaired glucose tolerance or both impaired fasting glucose and impaired glucose tolerance. The group whose 60-min glucose was <8.6 (n = 318) contained primarily persons with normal glucose tolerance (88%), whereas the majority of those whose 60-min value was ⩾8.6 (n = 172) had prediabetes (59%) and in particular combined impaired fasting glucose and impaired glucose tolerance.

CONCLUSION

Plasma glucose concentration of ⩾8.6 mmol/L 60 min post oral glucose identifies higher proportions of combined impaired fasting glucose and impaired glucose tolerance individuals as well as normal glucose tolerance and impaired fasting glucose individuals with a more adverse cardio-metabolic profile, contributing to observed increased overall risk of type 2 diabetes and other metabolic diseases.

The influence of high fat diet on plasma incretins and insulin concentrations in Sprague-Dawley rats with diet-induced obesity and glucose intolerance undergoing ileal transposition

BACKGROUND

The benefits of IT surgery are based on incretin effects. In this study we show the influence of high fat diet (HFD) used both before and after surgery, on ileal transposition (IT) effects.

METHODS

Forty-eight male rats were assigned to two groups: HFD and control diet (CD) fed rats. After eight weeks, HFD and CD fed rats were randomly assigned to two types of surgery: IT and SHAM, then for 50% of animals of each group the diet was changed, whereas the other 50% received the same type of diet. Eight weeks after surgery the incretin level, glucose tolerance as well as body mass and insulin level were assessed.

RESULTS

GLP-1 plasma concentration was significantly higher in the IT operated CD/CD group compared to fasting state and did not differ significantly from the SHAM operated CD/CD animals. IT influenced the glucose stimulated PYY plasma level when compared with SHAM operated animals in the CD/HFD group, where the PYY plasma level was higher than in the SHAM operated animals. The effect of IT as well as of pre and postoperative diet on GIP plasma levels were insignificant. The IT group members maintained on the CD were characterised by a lower fasting glucose level, both pre and postoperatively, compared with the SHAM operated animals. The effect of IT on the fasting glucose level in groups preoperatively maintained on an HFD was insignificant.

CONCLUSIONS

IT surgery itself seems to have rather limited incretin effects in rats, whose obesity is the result of HFD.

Relationship of lactation, BMI, and rs12255372 TCF7L2 polymorphism on the conversion to type 2 diabetes mellitus in women with previous gestational diabetes

Women with previous gestational diabetes mellitus (pGDM) have a high risk of developing postpartum type 2 diabetes mellitus (T2DM). This study aimed to analyze the relationship between lactation, BMI, and TCF7L2 polymorphisms in the conversion to T2DM in women with pGDM. One hundred and fifty-three women con pGDM were recruited from public hospitals of León Guanajuato México. Three groups: normal glucose tolerance (NGT), impaired glucose intolerance (IGT), and T2DM after the oral glucose tolerance test were formed. Metabolic and hormone variables were measured, and genotyping was made by PCR-RFLP. The questionnaire included data on lactation (yes/no), duration of lactation, and full lactation. After 35 (21-49) months from the last partum, 54% of women had an NGT, 30.7% IGT, and 15% T2DM. BMI and rs12255372 are associated with the risk of conversion to IGT and T2DM [OR = 1.07 (95% IC 1.0-1.14, p = .041; OR =2.14, 95% IC 1.01-4.55, p = .04 respectively), while the lactation shows a strong protective effects OR = 0.15 (95% IC 0.062-0.39, p = .00007), and an apparent interaction with rs12255372T decreasing the risk in carriers (OR =2.15; 95% IC 0.97-4.7, p = .05). BMI is an independent risk factor of IGT/T2DM development. The lactation shows a strong protective effect and a possible interaction with rs12255372 polymorphism.

Screening for prediabetes and risk of periodontal disease

OBJECTIVE

Diabetes and periodontitis are non-transmissible chronic disorders that exhibit a mutual relationship. A study was made to evaluate the risk of prediabetes and periodontal disease, and to explore the association between them.

METHODS

A descriptive cross-sectional study was made of 186 individuals over 18 years of age, without prediabetes or diabetes, or cognitive impairment. Subjects undergoing dental treatment and pregnant women were excluded. Prediabetes risk was assessed based on the Finnish Diabetes Risk Score (FINDRISC), and the individual risk of development and/or progression of periodontal disease was explored with a periodontal disease risk questionnaire.

RESULTS

A total of 135 gingival risk questionnaires and 142 FINDRISC questionnaires were correctly completed. The proportion of subjects with a low, moderate and high risk of periodontal disease was 60.36%, 38.74% and 0.9%, respectively. With regard to the FINDRISC, the proportion of individuals with low, slightly increased, moderately increased and high risk of prediabetes was 54.4%, 32.8%, 8%, and 4.8%, respectively. A significant linear correlation between the two scores was observed (r = 0.3659, p < 0.0005). The variables associated with a slightly increased risk of prediabetes were age, overweight and smoking, while the variables associated with a moderately increased or high risk were age 40-65 years, tooth loss, overweight and smoking.

CONCLUSIONS

These questionnaires may be of benefit to patients and can contribute to develop a chronic care model characterized by collaboration among different healthcare professionals.

Increased frequency of impaired fasting glucose and isolated systolic hypertension in Paget's disease of bone

PURPOSE

Scanty data about glucose metabolism and hypertension have been reported in Paget's disease of bone (PDB) to be related with increased cardiovascular mortality. The aim of the present study was to evaluate glucose and blood pressure levels in PDB, looking for their association with disease severity.

METHODS

We performed an observational cross-sectional study in 54 patients with PDB and 54 age, sex and BMI-matched controls. Glucose and blood pressure levels and parameters of bone and mineral metabolism were assessed.

RESULTS

Patients with PDB showed increased glucose levels (6.3 ± 1.7 vs 5.3 ± 1.4 mmol/l, p < 0.001) and prevalence of impaired fasting glucose (14.8%, 5.3-24.3 vs 1.9%, 0-5.4, p < 0.02) as well as enhanced systolic blood pressure (145.9 ± 21.3 vs 132.9 ± 18.9 mmHg, p < 0.005), pulse pressure (69.6 ± 20.0 vs 56.0 ± 16.9 mmHg, p < 0.01) and prevalence of isolated systolic hypertension (46.3%, 33.0-59.6 vs 16.7%, 6.7-26.6, p < 0.003) in comparison to controls. Moreover, we found a positive association of (1) glucose levels with ionized calcium and bone alkaline phosphatase; (2) both systolic and pulse pressure with total and bone alkaline phosphatase (p < 0.05). By multiple linear regression analysis (R² = 0.26; p < 0.05) serum ionized calcium correlated with glucose levels (β = 0.44; p < 0.04), after adjusting for age and BMI.

CONCLUSIONS

Our study shows increased fasting glucose, systolic and pulse pressure levels as well as enhanced prevalence of impaired fasting glucose and isolated systolic hypertension in PDB, potentially accounting for increased cardiovascular mortality. Furthermore, our findings suggest high serum calcium and/or increased bone alkaline phosphatase as a link between PDB and cardio-metabolic disorders.

The LepRdb/db mice model for studying glycation in the context of diabetes

BACKGROUND

Early (furosine) and advanced (carboxymethyllysine, CML) products of glycation (AGEs) have been reported as increased in plasma, tissues, and organs of diabetic people, indicating a direct link between glycation and type 2 diabetes (T2D). While murine models present some of the characteristics observed in diabetic humans, their pertinence as models of glycation, particularly for T2D, remains poorly described. The aim of this study was to characterize and compare glycation in several organs of two commonly studied murine models of T2D using stable isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS).

METHODS

Defining parameters of type 2 diabetes including body weight, fasting glycaemia, and glucose intolerance were measured in three different C57BL6 mouse models of T2D-the genetic LepR^db/db (db/db) model and two diet-induced obesity (DIO) models-and their respective controls. Furosine, free, and protein-bound CML were quantified in kidneys, lungs, heart, and liver by LC-MS/MS.

RESULTS

The obesity, hyperglycaemia, and glucose intolerance in db/db mice was accompanied by an increase of furosine and protein-bound CML levels in all organs relative to controls. The DIO models took several months to become obese, exhibited less severe hyperglycaemia and glucose intolerance, while glycation products were not significantly different between these groups (with the exception of furosine in liver and CML in lungs).

CONCLUSIONS

The db/db model better reflected the characteristics of human T2D compared with the DIO models and exhibited greater formation and accumulation of both furosine and protein-bound CML in all of the organs tested here.

Comparison of endothelial function and sympathetic nervous system activity along the glucose continuum in individuals with differing metabolic risk profiles and low dietary sodium intake

OBJECTIVE

Low sodium intake may trigger sympathetic nervous system (SNS) activation and endothelial dysfunction. Studies have not explored these associations along the glucose continuum. Accordingly, we compared endothelial function and SNS activity in individuals with low sodium intake and differing categories of metabolic risk along the glucose continuum. We hypothesized that low sodium intake is associated with (1) impairment of endothelial function and (2) higher SNS activity in individuals with higher metabolic risk.

RESEARCH DESIGN AND METHODS

In this prospective observational study, participants (n=54) with low sodium intake (single 24 hours urine sodium excretion <150 mmol/24 hours) were categorized based on oral glucose tolerance testing as: normal glucose tolerance (NGT, n=10), impaired glucose tolerance (IGT, n=15), treatment naive type 2 diabetes (T2D-) (n=12) or treated type 2 diabetes (T2D+) (n=17). We assessed endothelial function using pulse amplitude tonometry (PAT) derived reactive hyperemic index and PAT ratio; arterial stiffness via augmentation index; muscle sympathetic nerve activity (MSNA) using microneurography; cardiac baroreflex; heart rate; blood pressure; glycosylated hemoglobin A1c (HbA1c) and lipid profile.

RESULTS

Mean (SD) sodium excretion was 110.6 (26) mmol/24 hours. Compared with NGT, IGT and T2D-, the T2D+ group had lower MSNA (p=0.005), PAT ratio (p=0.04) and baroreflex sensitivity (p=0.0002) and an augmented heart rate (p=0.02). The T2D+ group had appropriate mean (SD) glycemic (HbA1c 7.2 (1.72)%), total cholesterol (4.2 (1.0) mmol/L), low-density lipoprotein (2.2 (1.0) mmol/L) and blood pressure (systolic 136 (13), diastolic 78 (12)) (mm Hg) control.

CONCLUSIONS

Individuals with T2D+ have impaired endothelial and baroreflex function, despite low sodium intake, appropriately managed cardiometabolic risk factors and lower SNS activity, compared with others along the glucose continuum. Whether low sodium intake is associated with modulation of the sympathovascular profile in T2D requires further investigation.

Cervical vagal nerve stimulation impairs glucose tolerance and suppresses insulin release in conscious rats

Previously, we reported that cervical vagal nerve stimulation (VNS) increases blood glucose levels and inhibits insulin secretion in anesthetized rats through afferent signaling. Since afferent signaling is also thought to mediate the therapeutic effects of VNS in patients with therapy-refractory epilepsy and major depression, the question arises if patients treated with VNS develop impaired glucose tolerance. Thus, we hypothesized that cervical VNS impairs glucose tolerance in conscious rats. Rats (n = 7) were instrumented with telemetric blood pressure sensors and right- or left-sided cervical vagal nerve stimulators (3 V, 5 Hz, 1 msec pulse duration, 1 h on 1 h off). Glucose tolerance tests (GTTs, 1.5 g dextrose/kg BW, i.p.) were performed after overnight fasting with the stimulators on or off (sham stimulation) in randomized order separated by 3-4 days. Overnight VNS did not alter mean levels of blood pressure or heart rate, but increased fasted blood glucose levels (140 ± 13 mg/dL vs. 109 ± 8 mg/dL, P < 0.05). The area under the blood glucose concentration curves of the GTTs was larger during VNS than sham stimulation (3499 ± 211 mg/dL*h vs. 1810 ± 234 mg/dL*h, P < 0.05). One hour into the GTTs, the serum insulin concentrations had decreased during VNS (-0.57 ± 0.25 ng/mL, P < 0.05) and increased during sham stimulation (+0.71 ± 0.15 ng/mL, P < 0.05) compared to the fasted baseline levels. These results demonstrate that chronic cervical VNS elevates fasted blood glucose levels and impairs glucose tolerance likely through inhibition of glucose-induced insulin release in conscious rats. It remains to be determined if patients treated with VNS are at greater risk of developing glucose intolerance and type 2 diabetes.

Zinc and Insulin Resistance: Biochemical and Molecular Aspects

Studies have shown the participation of minerals in mechanisms involved in the pathogenesis of insulin resistance. Zinc, in particular, seems to play an important role in the secretion and action of this hormone. Therefore, the aim of this review is to understand the role of zinc in increasing insulin sensitivity. We conducted a search of articles published in the PubMed and ScienceDirect database selected from March 2016 to February 2018, using the keywords "zinc," "insulin," "insulin resistance," "insulin sensitivity," and "supplementation." Following the eligibility criteria were selected 53 articles. The scientific evidences presented in this review show the importance of zinc and their carrier proteins in the synthesis and secretion of insulin, as well as in the signaling pathway of action of this hormone. Zinc deficiency is associated with glucose intolerance and insulin resistance; however, the effectiveness of the intervention with the zinc supplementation is still inconclusive.

Programming of central and peripheral insulin resistance by low birthweight and postnatal catch-up growth in male mice

AIMS

Intra-uterine growth restriction (IUGR) followed by accelerated postnatal growth is associated with an increased risk of obesity and type 2 diabetes. We aimed to determine central and peripheral insulin sensitivity in mice that underwent IUGR followed by postnatal catch-up growth and investigate potential molecular mechanisms underpinning their physiology.

METHODS

We used a C57BL/6J mouse model of maternal diet-induced IUGR (maternal diet, 8% protein) followed by cross-fostering to a normal nutrition dam (maternal diet, 20% protein) and litter size manipulation to cause accelerated postnatal catch-up growth. We performed intracerebroventricular insulin injection and hyperinsulinaemic-euglycaemic clamp studies to examine the effect of this early nutritional manipulation on central and peripheral insulin resistance. Furthermore, we performed quantitative real-time PCR and western blotting to examine the expression of key insulin-signalling components in discrete regions of the hypothalamus.

RESULTS

IUGR followed by accelerated postnatal growth caused impaired glucose tolerance and peripheral insulin resistance. In addition, these 'recuperated' animals were resistant to the anorectic effects of central insulin administration. This central insulin resistance was associated with reduced protein levels of the p110β subunit of phosphoinositide 3-kinase (PI3K) and increased serine phosphorylation of IRS-1 in the arcuate nucleus (ARC) of the hypothalamus. Expression of the gene encoding protein tyrosine phosphatase 1B (PTP1B; Ptpn1) was also increased specifically in this region of the hypothalamus.

CONCLUSIONS/INTERPRETATION

Mice that undergo IUGR followed by catch-up growth display peripheral and central insulin resistance in adulthood. Recuperated offspring show changes in expression/phosphorylation of components of the insulin signalling pathway in the ARC. These defects may contribute to the resistance to the anorectic effects of central insulin, as well as the impaired glucose homeostasis seen in these animals.

Glucose regulation and physical performance among older people: the Helsinki Birth Cohort Study

AIMS

To assess whether disturbances in glucose regulation are associated with impairment in physical performance during a 10-year follow-up.

METHODS

475 Men and 603 women from the Helsinki Birth Cohort Study were studied. Glucose regulation was evaluated with a 2-h 75-g oral glucose tolerance test (OGTT) in 2001-2004. Subjects were categorised as having either impaired fasting glucose (IFG), impaired glucose tolerance (IGT), newly diagnosed diabetes or previously known diabetes. Physical performance was assessed approximately 10 years later using the validated senior fitness test (SFT). The relationship between glucose regulation and the overall SFT score was estimated using multiple linear regression models.

RESULTS

The mean age was 70.8 years for men and 71.0 years for women when physical performance was assessed. The mean SFT score for the whole population was 45.0 (SD 17.5) points. The SFT score decreased gradually with increased impairment in glucose regulation. Individuals with previously known diabetes had the lowest overall SFT score in the fully adjusted model (mean difference compared to normoglycaemic individuals - 11.56 points, 95% CI - 16.15 to - 6.98, p < 0.001). Both individuals with newly diagnosed diabetes and individuals with IGT had significantly poorer physical performance compared to those with normoglycaemia. No significant difference in physical performance was found between those with IFG and those with normoglycaemia.

CONCLUSIONS

Among older people, impaired glucose regulation is strongly related with poor physical performance. More severe disturbances in glucose regulation are associated with a greater decrease in physical function, indicating the importance of diagnosing these disturbances at an early stage.

Differential effects of the circadian system and circadian misalignment on insulin sensitivity and insulin secretion in humans

Glucose tolerance is lower at night and higher in the morning. Shift workers, who often eat at night and experience circadian misalignment (i.e. misalignment between the central circadian pacemaker and the environmental/behavioural cycles), have an increased risk of type 2 diabetes. To determine the separate and relative impacts of the circadian system, behavioural/environmental cycles, and their interaction (i.e. circadian misalignment) on insulin sensitivity and β-cell function, the oral minimal model was used to quantitatively assess the major determinants of glucose control in 14 healthy adults using a randomized, cross-over design with two 8-day laboratory protocols. Both protocols involved 3 baseline inpatient days with habitual sleep/wake cycles, followed by 4 inpatient days with the same nocturnal bedtime (circadian alignment) or with 12-hour inverted behavioural/environmental cycles (circadian misalignment). The data showed that circadian phase and circadian misalignment affect glucose tolerance through different mechanisms. While the circadian system reduces glucose tolerance in the biological evening compared to the biological morning mainly by decreasing both dynamic and static β-cell responsivity, circadian misalignment reduced glucose tolerance mainly by lowering insulin sensitivity, not by affecting β-cell function.

The reversal effect of physical exercise on aging-related increases in APPL2 content in skeletal muscle

AIMS

The aim of this study was to evaluate the effects of aging on intracellular adiponectin signaling and the possible therapeutic effect of physical exercise.

MAIN METHODS

Fischer 344 rats were distributed in the following groups: Young (3 months old); Sedentary Old (Old, 27 months old); and Old Exercised (Old-Exe, 27 months old), which were subjected to a short-term exercise training protocol.

KEY FINDINGS

The results showed that the old rats presented glucose intolerance without increased adiposity. However, short-term exercise training reversed this disorder, which was associated with a decrease in the pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif (APPL) isoform 2 (APPL2) content. The APPL isoform 1 (APPL1) and TRB3 (Tribbles homolog 3) contents were not altered. Akt phosphorylation was only increased in the old exercised rats. There was a reduction in the content of adiponectin receptor 1 in the old rats.

SIGNIFICANCE

The short-term exercise training protocol was able to decrease APPL2 content in the skeletal muscle, which was accompanied by an improvement in the glucose tolerance of the old Fischer 344 rats. These findings provide new evidence supporting the role of physical exercise as a non-pharmacological therapeutic intervention to attenuate age-related deficits.

The relationship between sleep and cognitive function in patients with prediabetes and type 2 diabetes

AIMS

Diabetes is linked to cognitive impairment. Sleep plays a role in memory consolidation. Sleep disturbances, commonly found in patients with diabetes, were shown to be related to cognitive dysfunction. This study explored the role of sleep in cognitive function of patients with abnormal glucose tolerance.

METHODS

A total of 162 patients (81 type 2 diabetes and 81 prediabetes) participated. Sleep duration and sleep efficiency (an indicator of sleep quality) were obtained using 7-day actigraphy recordings. Obstructive sleep apnea (OSA) was screened using an overnight in-home monitor. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA). Three sub-scores of MoCA, visuoexecutive function, attention and delayed recall, were also analyzed.

RESULTS

Mean age was 54.8 (10.2) years. OSA was diagnosed in 123 participants (76.9%). Mean sleep duration was 6.0 (1.0) h and sleep efficiency was 82.7 (8.1) %. Sleep duration and OSA severity were not related to MoCA scores. Higher sleep efficiency was associated with higher MoCA scores (p = 0.003), and having diabetes (vs. prediabetes) was associated with lower MoCA scores (p = 0.001). After adjusting covariates, both having diabetes (vs. prediabetes) (B = - 1.137, p = 0.002) and sleep efficiency (B = 0.085, p < 0.001) were independently associated with MoCA scores. In addition, diabetes (B = - 0.608, p < 0.001) and sleep efficiency (B = 0.038, p < 0.001) were associated with visuoexecutive function. Sleep parameters were not related to delayed recall or attention scores.

CONCLUSION

Lower sleep efficiency is independently associated with lower cognitive function in patients with abnormal glucose tolerance. Whether sleep optimization may improve cognitive function in these patients should be explored.

Dietary manganese and type 2 diabetes mellitus: two prospective cohort studies in China

AIMS/HYPOTHESIS

The association between dietary Mn and type 2 diabetes is unclear. We aimed to elucidate whether dietary Mn is associated with type 2 diabetes, to investigate whether this association is independent of dietary total antioxidant capacity (TAC) and to explore the underlying mechanisms in their association.

METHODS

Two prospective cohorts of 3350 and 7133 Chinese adults (20-74 years old) were enrolled including, respectively, 244 and 578 individuals newly diagnosed with type 2 diabetes, with mean values of 4.2 and 5.3 years of follow-up. Cox's proportional-hazards regression and linear regression were performed to investigate the association between dietary Mn and type 2 diabetes (diagnosed by OGTT) or HbA_lc and to analyse the joint association between dietary Mn and TAC. Restricted cubic spline (RCS) regression was applied to the non-linear association between dietary Mn and incidence of type 2 diabetes. Mediation analysis was applied to explore potential mediators in their association in a subgroup of 500 participants.

RESULTS

Dietary Mn intakes were 4.58 ± 1.04 and 4.61 ± 1.08 (mean ± SD) mg/day in the two cohorts. Dietary Mn was inversely associated with type 2 diabetes incidence and HbA_lc concentration in both cohorts (p_trend < 0.01 and <0.01 for type 2 diabetes, and p_trend < 0.01 and =0.02 for HbA_lc, respectively, in each cohort) independent of TAC, adjusted for age, sex, BMI, tobacco use, alcohol consumption, physical activity, diabetes inheritance, total energy, carbohydrate, total fatty acids, fibre, calcium, Mg, hypertension, hyperlipidaemia, and impaired glucose tolerance or FBG (all at baseline). Their inverse association was stronger in the presence of diets with high, compared with low, TAC. In RCS, intakes of >6.01 and 6.10-6.97 mg/day were associated with a significantly lower type 2 diabetes incidence in the two respective cohorts. Mediation analysis showed that high plasma Mn and low oxidative stress (increased Mn superoxide dismutase and decreased 8-hydroxydeoxyguanosine) contributed to the association between dietary Mn and both type 2 diabetes and HbA_lc.

CONCLUSIONS/INTERPRETATION

Dietary Mn was inversely associated with type 2 diabetes independently of TAC. In addition, this association was stronger in a high- rather than low-TAC diet. Plasma Mn and oxidative stress were mediators in the association between dietary Mn and type 2 diabetes. Future studies on absolute Mn intake should be conducted to study the potential non-linearity and optimal levels of dietary Mn and type 2 diabetes.

Novel approaches to restore beta cell function in prediabetes and type 2 diabetes

The World Health Organization estimates that diabetes prevalence has risen from 108 million in 1980 to 422 million in 2014, with type 2 diabetes accounting for more than 90% of these cases. Furthermore, the prevalence of prediabetes (impaired fasting glucose and/or impaired glucose tolerance) is more than 40% in some countries and is associated with a global rise in obesity. Therefore it is imperative that we develop new approaches to reduce the development of prediabetes and progression to type 2 diabetes. In this review, we explore the gains made over the past decade by focused efforts to improve insulin secretion by the beta cell or insulin sensitivity of target tissues. We also describe multitasking candidates, which could improve both beta cell dysfunction and peripheral insulin sensitivity. Moreover, we highlight provocative findings indicating that additional glucose regulatory tissues, such as the brain, may be key therapeutic targets. Taken together, the promise of these new multi-faceted approaches reinforces the importance of understanding and tackling type 2 diabetes pathogenesis from a multi-tissue perspective.

Relationship between serum adipsin and the first phase of glucose-stimulated insulin secretion in individuals with different glucose tolerance

AIMS/INTRODUCTION

To detect serum adipsin levels in individuals with different glucose tolerance, and investigate the relationship between adipsisn and the first phase of insulin secretion.

MATERIALS AND METHODS

A total of 56 patients with newly diagnosed type 2 diabetes mellitus, 36 patients with impaired glucose tolerance (IGT) and 45 individuals with normal glucose tolerance were enrolled. Intravenous glucose tolerance tests were carried out to evaluate pancreatic β-cell function. The serum levels of adipsin, interleukin-1β and high-sensitivity C-reactive protein were assayed.

RESULTS

Serum adipsin levels were significantly lower in the type 2 diabetes mellitus and the IGT patients than those in the normal glucose tolerance group (P < 0.05). The acute insulin response and area under the curve showed a progressive decrease in the normal glucose tolerance and IGT groups, and decreased to the lowest levels in the type 2 diabetes mellitus group (P < 0.05). Adipsin was found to be negatively correlated with waist-to-hip ratio, free fatty acid, fasting plasma glucose, 2-h postprandial plasma glucose, glycated hemoglobin, homeostasis model assessment of insulin resistance, interleukin-1β and high-sensitivity C-reactive protein (P < 0.05 or P < 0.001), and positively correlated with homeostasis model assessment of β-cell function, high-density lipoprotein cholesterol, the area under the curve of the first phase insulin secretion and acute insulin response (P < 0.05 or P < 0.001). Stepwise multiple regression analysis showed that homeostasis model assessment for β-cell function and acute insulin response were independently related to adipsin (P < 0.05).

CONCLUSIONS

Serum adipsin levels were lower in type 2 diabetes mellitus and IGT patients, and correlated with the first phase of insulin secretion. Adipsin might be involved in the pathology of type 2 diabetes mellitus.

The Transplantation of ω3 PUFA-Altered Gut Microbiota of fat-1 Mice to Wild-Type Littermates Prevents Obesity and Associated Metabolic Disorders

Altering the gut microbiome may be beneficial to the host and recently arose as a promising strategy to manage obesity. Here, we investigated the relative contribution of ω3 polyunsaturated fatty acid (PUFA)-mediated alterations in the microbiota to metabolic parameter changes in mice. Four groups were compared: male fat-1 transgenic mice (with constitutive production of ω3 PUFAs) and male wild-type (WT) littermates fed an obesogenic (high fat/high sucrose [HFHS]) or a control diet. Unlike WT mice, HFHS-fed fat-1 mice were protected against obesity, glucose intolerance, and hepatic steatosis. Unlike WT mice, fat-1 mice maintained a normal barrier function, resulting in a significantly lower metabolic endotoxemia. The fat-1 mice displayed greater phylogenic diversity in the cecum, and fecal microbiota transplantation from fat-1 to WT mice was able to reverse weight gain and to normalize glucose tolerance and intestinal permeability. We concluded that the ω3 PUFA-mediated alteration of gut microbiota contributed to the prevention of metabolic syndrome in fat-1 mice. It occurred independently of changes in the PUFA content of host tissues and may represent a promising strategy to prevent metabolic disease and preserve a lean phenotype.