Adipose Tissue Insulin Sensitivity Research Articles

Potential roles of bone morphogenetic protein-9 in glucose and lipid homeostasis.

Bone morphogenetic protein-9 (BMP-9) is a novel cytokine which is cloned from the fetal mouse liver cDNA library and belongs to the member of the transforming growth factor-β (TGF-β) superfamily. BMP-9 is mainly secreted by the liver and exerts a variety of physiological functions. In this review, we present the latest knowledge on the biochemistry of BMP-9 and its role in glucose metabolism and lipid homeostasis. We introduced the expression site, structure, synthesis, and secretion of BMP-9, as well as BMP-9 signaling pathway. We also discuss the effects of BMP-9 on glucose metabolism and lipid metabolism in different organs. BMP-9 can regulate glucose and lipid homeostasis in the body by inhibiting liver gluconeogenesis, transforming white adipose tissue to brown adipose tissue, promoting muscle glycogen synthesis, increasing the uptake and utilization of glucose by muscle tissue, increasing liver and adipose tissue insulin sensitivity, promoting insulin synthesis and secretion, inhibiting liver lipid deposition, and playing a leptin-like role. Finally, through the results of animal intervention studies and human clinical studies in the review, we deeply understand the association of BMP-9 with obesity, insulin resistance (IR), type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD), which provides new ideas for the prevention and treatment of diseases.

Effects of weight loss during a very low carbohydrate diet on specific adipose tissue depots and insulin sensitivity in older adults with obesity: a randomized clinical trial

BackgroundInsulin resistance and accumulation of visceral adipose tissue (VAT) and intermuscular adipose tissue (IMAT) place aging adults with obesity at high risk of cardio-metabolic disease. A very low carbohydrate diet (VLCD) may be a means of promoting fat loss from the visceral cavity and skeletal muscle, without compromising lean mass, and improve insulin sensitivity in aging adults with obesity.ObjectiveTo determine if a VLCD promotes a greater loss of fat (total, visceral and intermuscular), preserves lean mass, and improves insulin sensitivity compared to a standard CHO-based/low-fat diet (LFD) in older adults with obesity.DesignThirty-four men and women aged 60–75 years with obesity (body mass index [BMI] 30-40 kg/m2) were randomized to a diet prescription of either a VLCD (< 10:25:> 65% energy from CHO:protein:fat) or LFD diet (55:25:20) for 8 weeks. Body composition by dual-energy X-ray absorptiometry (DXA), fat distribution by magnetic resonance imaging (MRI), insulin sensitivity by euglycemic hyperinsulinemic clamp, and lipids by a fasting blood draw were assessed at baseline and after the intervention.ResultsParticipants lost an average of 9.7 and 2.0% in total fat following the VLCD and LFD, respectively (p < 0.01). The VLCD group experienced ~ 3-fold greater loss in VAT compared to the LFD group (− 22.8% vs − 1.0%, p < 0.001) and a greater decrease in thigh-IMAT (− 24.4% vs − 1.0%, p < 0.01). The VLCD group also had significantly greater thigh skeletal muscle (SM) at 8 weeks following adjustment for change in total fat mass. Finally, the VLCD had greater increases in insulin sensitivity and HDL-C and decreases in fasting insulin and triglycerides compared to the LFD group.ConclusionsWeight loss resulting from consumption of a diet lower in CHO and higher in fat may be beneficial for older adults with obesity by depleting adipose tissue depots most strongly implicated in poor metabolic and functional outcomes and by improving insulin sensitivity and the lipid profile.Trial registrationNCT02760641. Registered 03 May 2016 - Retrospectively registered.

Obesity-Induced Increase in Cystatin C Alleviates Tissue Inflammation.

We recently demonstrated that removal of one kidney (uninephrectomy [UniNx]) in mice reduced high-fat diet (HFD)-induced adipose tissue inflammation, thereby improving adipose tissue and hepatic insulin sensitivity. Of note, circulating cystatin C (CysC) levels were increased in UniNx compared with sham-operated mice. Importantly, CysC may have anti-inflammatory properties, and circulating CysC levels were reported to positively correlate with obesity in humans and as shown here in HFD-fed mice. However, the causal relationship of such observation remains unclear. HFD feeding of CysC-deficient (CysC knockout [KO]) mice worsened obesity-associated adipose tissue inflammation and dysfunction, as assessed by proinflammatory macrophage accumulation. In addition, mRNA expression of proinflammatory mediators was increased, whereas markers of adipocyte differentiation were decreased. Similar to findings in adipose tissue, expression of proinflammatory cytokines was increased in liver and skeletal muscle of CysC KO mice. In line, HFD-induced hepatic insulin resistance and impairment of glucose tolerance were further aggravated in KO mice. Consistently, chow-fed CysC KO mice were more susceptible to lipopolysaccharide-induced adipose tissue inflammation. In people with obesity, circulating CysC levels correlated negatively with adipose tissue Hif1α as well as IL6 mRNA expression. Moreover, healthy (i.e., insulin-sensitive) subjects with obesity had significantly higher mRNA expression of CysC in white adipose tissue. In conclusion, CysC is upregulated under obesity conditions and thereby counteracts inflammation of peripheral insulin-sensitive tissues and, thus, obesity-associated deterioration of glucose metabolism.

Effects of High-Intensity Exercise Training on Adipose Tissue Mass, Glucose Uptake and Protein Content in Pre- and Post-menopausal Women.

The menopausal transition is accompanied by changes in adipose tissue storage, leading to an android body composition associated with increased risk of type 2 diabetes and cardiovascular disease in post-menopausal women. Estrogens probably affect local adipose tissue depots differently. We investigated how menopausal status and exercise training influence adipose tissue mass, adipose tissue insulin sensitivity and adipose tissue proteins associated with lipogenesis/lipolysis and mitochondrial function. Healthy, normal-weight pre- (n = 21) and post-menopausal (n = 20) women participated in high-intensity exercise training three times per week for 12 weeks. Adipose tissue distribution was determined by dual-energy x-ray absorptiometry and magnetic resonance imaging. Adipose tissue glucose uptake was assessed by positron emission tomography/computed tomography (PET/CT) by the glucose analog [18F]fluorodeoxyglucose ([18F]FDG) during continuous insulin infusion (40 mU·m−2·min−1). Protein content associated with insulin signaling, lipogenesis/lipolysis, and mitochondrial function were determined by western blotting in abdominal and femoral white adipose tissue biopsies. The mean age difference between the pre- and the post-menopausal women was 4.5 years. Exercise training reduced subcutaneous (~4%) and visceral (~6%) adipose tissue masses similarly in pre- and post-menopausal women. Insulin-stimulated glucose uptake, assessed by [18F]FDG-uptake during PET/CT, was similar in pre- and post-menopausal women in abdominal, gluteal, and femoral adipose tissue depots, despite skeletal muscle insulin resistance in post- compared to pre-menopausal women in the same cohort. Insulin-stimulated glucose uptake in adipose tissue depots was not changed after 3 months of high-intensity exercise training, but insulin sensitivity was higher in visceral compared to subcutaneous adipose tissue depots (~139%). Post-menopausal women exhibited increased hexokinase and adipose triglyceride lipase content in subcutaneous abdominal adipose tissue. Physical activity in the early post-menopausal years reduces abdominal obesity, but insulin sensitivity of adipose tissue seems unaffected by both menopausal status and physical activity.

1704-P: Coexistence of Hypoadiponectinemia and Impaired Adipose Tissue Insulin Sensitivity Increases the Risk of Metabolic Abnormality Due to Muscle Insulin Resistance in Nonobese Japanese Men

Both reduced circulating adiponectin (AN) and impaired adipose tissue insulin sensitivity (ATIS) are observed in obese subjects with insulin resistance (IR). While Asians easily develop metabolic disease featured with IR without obesity, we found that both reduced AN and impaired ATIS are individually associated with muscle IR and accumulation of intrahepatic lipid (IHL) in non-obese Japanese men. However, it is entirely unclear whether the coexistence of reduced AN and impaired ATIS is associated with metabolic abnormality.To clarify this, we studied 94 non-obese Japanese men. We evaluated tissue specific insulin sensitivity by 2-step hyperinsulinemic euglycemic clamp and calculated ATIS as a degree of insulin-mediated suppression of circulating free fatty acid. IHL was measured by 1H-MRS. Then, we divided the subjects into 4 groups based on their median AN and ATIS and assessed the effect of AN and ATIS on the parameters related to muscle IR. As shown in Figure, the levels of IHL in the patients with both reduced AN and impaired ATIS were higher than other groups. The similar tendency was also observed regarding the serum triglyceride level and muscle IR. These results suggested that coexistence of reduced AN and impaired ATIS increases the risk of metabolic abnormality due to muscle IR in non-obese Japanese men. Disclosure M. Kiya: None. Y. Tamura: Advisory Panel; Self; Astellas Pharma Inc. Research Support; Self; Kowa Company, Ltd. Speaker’s Bureau; Self; Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd. K. Takeno: None. Y. Someya: None. S. Kakehi: None. M. Sato: None. N. Yamasaki: None. S. Kadowaki: None. R. Suzuki: None. Y. Furukawa: None. D. Sugimoto: None. H. Kaga: None. T. Funayama: None. H. Satoh: None. R. Kawamori: None. H. Watada: Advisory Panel; Self; Abbott, Ajinomoto, Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Fuji Film, Janssen Pharmaceuticals, Inc., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis, Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. Research Support; Self; Astellas Pharma Inc., Bayer Yakuhin, Ltd., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharma K.K., Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Pfizer Japan Inc., Sanofi-Aventis, Sanwa Kagaku Kenkyusho, Shionogi &amp; Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited, Yakult. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Bayer Yakuhin, Ltd., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis, Sanwa Kagaku Kenkyusho, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited. Funding High Technology Research Center; Strategic Research Foundation at Private Universities; Japan Ministry of Education, Culture, Sports, Science and Technology (23680069, 26282197, 17K19929); Japan Diabetes Foundation; Suzuken Memorial Foundation; Mitsukoshi Welfare Foundation; Diabetes Masters Conference

1987-P: Inflammation and Insulin Resistance in Adipose Tissue

Background: Adipose tissue inflammation is linked to adipose tissue insulin resistance. However, whether this is a causal relationship remains controversial. Therefore, we aimed to explore the relationship between measures of adipose tissue inflammation and adipose tissue insulin sensitivity over a wide range of body fat distribution and adipose tissue insulin sensitivity. Methods: We recruited a total of 87 volunteers (30 men and 57 women). Adipose tissue insulin sensitivity was quantified as the insulin concentration required for a 50% suppression of lipolysis (IC50). Lipolysis was measured as steady-state palmitate flux before and during a hyperinsulinemic-euglycemic clamp. Adipose tissue macrophage (ATM) was quantified by immunohistochemistry with antibodies against CD68 (total ATM), CD14 (pro-inflammatory ATM) and CD206 (anti-inflammatory ATM) and senescent preadipocyte content was quantified by β-galactosidase positivity using fluorescent microscopy in abdominal and femoral fat biopsies. Results: Total ATM content was only weakly associated with IC50 in abdominal fat (r=0.26, p=0.01) and no association was observed for femoral fat. No association was observed between IC50 and pro-inflammatory ATM content. Anti-inflammatory ATM content was associated with IC50 in abdominal (r=0.46, p&amp;lt;0.001) and femoral (r=0.33, p=0.02) fat. Senescent preadipocyte content was weakly associated with IC50 in femoral fat (r=0.36, p=0.01), but no association was observed in abdominal fat. Fat cell size was strongly associated with IC50 in both abdominal (r=0.6 p&amp;lt;0.001) and femoral (r=0.48, p&amp;lt;0.01) fat. Conclusions: ATM content is only weakly associated to adipose tissue insulin sensitivity. Only the content of anti-inflammatory, not pro-inflammatory macrophages, was associated with adipose tissue insulin sensitivity. This argues against pro-inflammatory macrophages as mediators of insulin resistance in adipose tissue. Disclosure E. Søndergaard: None. A.E. Espinosa De Ycaza: None. M. Morgan-Bathke: None. K. Lytle: None. D.A. Delivanis: None. B.G. Carranza Leon: None. M.D. Jensen: None. Funding National Institutes of Health (DK40404, DK45343)

1861-P: Short-Term Overfeeding with Dairy Fat Impairs Insulin Sensitivity in Muscle and Liver but Increases Adipose Tissue Insulin Sensitivity and Suppresses Postprandial Glucose Rise in Healthy Nonobese Men

Previous studies have demonstrated that saturated fat intake increases the risk of type 2 diabetes (T2DM) due to reduction of insulin sensitivity. On the other hand, the consumption of dairy fat that predominantly includes saturated fat is reported to be protective against T2DM. However, its underlying mechanism has not been fully understood. To address this, we recruited 21 healthy non-obese men and evaluated metabolic changes before and after 6-day high-calorie, high-fat diet (HCHFD) consisting of a regular diet plus 45% energy excess by supplementation with dairy fat. We measured intrahepatic lipid (IHL) and intramyocellular lipid (IMCL) in tibialis anterior muscle by 1H-MRS and metabolic rate during sleeping by metabolic chamber. One day after the measurement, we performed meal test, and the next day, we measured tissue specific insulin sensitivity by 2-step hyperinsulinemic euglycemic clamp. After the HCHFD, body weight was increased by 0.4 kg, and IMCL and IHL were also increased by 47% and 200%, respectively. On the other hand, hepatic and muscle insulin sensitivity showed only a modest decrease by 8% and 4%, respectively. Consistently, fasting endogenous glucose production elevated by only 3% without altering insulin level; however, unexpectedly, fasting free fatty acid (FFA) greatly decreased by 43%, suggesting increased adipose tissue insulin sensitivity (ATIS), and total ketone body levels was decreased by 53% and glucose oxidation during sleeping was consistently increased. Further, post-prandial glucose rise during the meal test was suppressed after the HCHFD, although insulin secretion was lower during the test. In conclusion, short-term HCHFD by dairy fat supplementation increased ATIS and glucose oxidation, and suppressed post-prandial glucose rise with lowered insulin secretion. These metabolic changes by dairy fat may be beneficial to prevent T2DM. Disclosure D. Sugimoto: None. Y. Tamura: Advisory Panel; Self; Astellas Pharma Inc. Research Support; Self; Kowa Company, Ltd. Speaker’s Bureau; Self; Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd. S. Kadowaki: None. Y. Someya: None. H. Kaga: None. R. Suzuki: None. S. Kakehi: None. N. Yamasaki: None. M. Sato: None. A. Kanazawa: Speaker’s Bureau; Self; Novartis Pharma K.K., Sanofi, Takeda Pharmaceutical Company Limited. R. Kawamori: None. H. Watada: Advisory Panel; Self; Abbott, Ajinomoto, Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Fuji Film, Janssen Pharmaceuticals, Inc., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis, Takeda Pharmaceutical Company Limited, Terumo Medical Corporation. Research Support; Self; Astellas Pharma Inc., Bayer Yakuhin, Ltd., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharma K.K., Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Pfizer Japan Inc., Sanofi-Aventis, Sanwa Kagaku Kenkyusho, Shionogi &amp; Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited, Yakult. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Bayer Yakuhin, Ltd., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Kowa Company, Ltd., Kyowa Hakko Kirin Co., Ltd., Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi-Aventis, Sanwa Kagaku Kenkyusho, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited. Funding Ministry of Education, Culture, Sports, Science and Technology of Japan (18H03196)

1698-P: Obesity-Induced Increase in Cystatin C Alleviates Tissue Inflammation and Hepatic Insulin Resistance

Removal of one kidney (uninephrectomy; UniNx) in mice reduced high fat-diet (HFD)-induced adipose tissue inflammation thereby improving adipose tissue and hepatic insulin sensitivity. Such finding was accompanied by increased circulating cystatin C levels in UniNx compared to sham-operated mice. Importantly, cystatin C may have anti-inflammatory properties, and circulating cystatin C levels were reported to positively correlate with obesity as well as type 2 diabetes. However, the causal relationship of such correlation remains unclear. Herein, HFD feeding of cystatin C-deficient (CysC KO) mice aggravated obesity-associated adipose tissue dysfunction and inflammation, as reflected by an accumulation of pro-inflammatory monocytes and elevated expression of pro-inflammatory mediators. Moreover, markers of adipocyte differentiation were decreased. Similarly to findings in adipose tissue, expression of pro-inflammatory cytokines was increased in liver and skeletal muscle of HFD-fed CysC KO mice. In line, HFD-induced hepatic insulin resistance and impairment of glucose tolerance were further aggravated in knockout mice. Consistently, chow-fed CysC KO mice were more susceptible to lipopolysaccharide (LPS)-induced adipose tissue inflammation. In people with obesity, circulating cystatin C levels correlated negatively with mRNA expression of pro-inflammatory cytokines such as Hif1α as well as IL-6. Moreover, healthy (i.e., insulin-sensitive) subjects with obesity depicted significantly higher mRNA expression of cystatin C in subcutaneous white adipose tissue. In conclusion, cystatin C is upregulated under obesity conditions and thereby counteracts inflammation of peripheral insulin-sensitive tissues and, thus, obesity-associated deterioration of glucose metabolism. Disclosure M.A. Dedual: None. S. Wueest: None. T. Challa: None. F. Lucchini: None. T. Aeppli: None. M. Borsigova: None. A.A. Mauracher: None. S. Vavassori: None. J. Pachlopnik Schmid: Advisory Panel; Self; Novartis AG, Swedish Orphan Biovitrum. M. Blüher: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk A/S, Sanofi. Speaker’s Bureau; Self; Amgen, Novartis AG. D. Konrad: Research Support; Self; Novo Nordisk A/S. Funding Children’s Research Centre; University Children’s Hospital Zurich; University of Zurich (FK-18-027); Swiss National Science Foundation (310030-160129, 10030-179344); Wolfermann-Nägeli Foundation

Integration of whole-body [18F]FDG PET/MRI with non-targeted metabolomics can provide new insights on tissue-specific insulin resistance in type 2 diabetes

Alteration of various metabolites has been linked to type 2 diabetes (T2D) and insulin resistance. However, identifying significant associations between metabolites and tissue-specific phenotypes requires a multi-omics approach. In a cohort of 42 subjects with different levels of glucose tolerance (normal, prediabetes and T2D) matched for age and body mass index, we calculated associations between parameters of whole-body positron emission tomography (PET)/magnetic resonance imaging (MRI) during hyperinsulinemic euglycemic clamp and non-targeted metabolomics profiling for subcutaneous adipose tissue (SAT) and plasma. Plasma metabolomics profiling revealed that hepatic fat content was positively associated with tyrosine, and negatively associated with lysoPC(P-16:0). Visceral adipose tissue (VAT) and SAT insulin sensitivity (Ki), were positively associated with several lysophospholipids, while the opposite applied to branched-chain amino acids. The adipose tissue metabolomics revealed a positive association between non-esterified fatty acids and, VAT and liver Ki. Bile acids and carnitines in adipose tissue were inversely associated with VAT Ki. Furthermore, we detected several metabolites that were significantly higher in T2D than normal/prediabetes. In this study we present novel associations between several metabolites from SAT and plasma with the fat fraction, volume and insulin sensitivity of various tissues throughout the body, demonstrating the benefit of an integrative multi-omics approach.

SAT-624 Predictive Ability of Lipoprotein Insulin Resistance (LPIR) Score in South Asians: A Comparison of Surrogate Indices of Insulin Sensitivity/Resistance

South Asians (SA) are at higher risk for developing insulin resistance (IR) and type 2 diabetes. Consequently, identifying IR in this population is important. Lack of standardization and harmonization of insulin assays limit the clinical use of insulin-based surrogate indexes of insulin resistance. The lipoprotein insulin resistance (LPIR) score, a metabolomic marker, reflects the lipoprotein abnormalities observed in insulin-resistant states. The reliability of the LPIR score to predict IR in South Asians is currently unknown. In this study, we aimed to evaluate the predictive accuracy of LPIR compared to other fasting-based surrogate indices in SA.In a cross-sectional study of 59 non-diabetic SA subjects (age 36 ± 8 years, BMI 26.5 ± 5.2 kg/m2), we used calibration model analysis to assess the ability of the LPIR score and other simple surrogate indices [homeostasis model assessment (HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and Adipose tissue insulin sensitivity (Adipo-SI)] to predict insulin sensitivity derived from the reference frequently sampled intravenous glucose tolerance test (FSIVGTT) and Minimal Model analysis (SiMM). LPIR scores were calculated using six lipoprotein particle concentrations and sizes measured by nuclear magnetic resonance (NMR) spectroscopy. Further, quantitative predictive accuracy and index comparisons were determined by root mean squared error (RMSE) of prediction and leave-one-out cross-validation-type RMSE of prediction (CVPE). Receiver operating characteristic (ROC) curve analysis was performed to determine how well LPIR distinguished insulin resistant individuals, categorized as an SiMM < 3.As determined by calibration model analysis, Adipo-SI, HOMA-IR, and QUICKI showed moderate correlations with for SiMM (Adipo-SI: r = 0.66; HOMA-IR: r = 0.60; QUICKI: r = 0.57, p = <0.0001). No significant differences were noted among CVPE or RMSE from any of the routinely used surrogate indices when compared with LPIR. The ROC area under the curve was 0.76 (95% CI 0.64–0.87) suggesting that LPIR performed well in identifying insulin resistant subjects. The optimal cut-off in IR individuals was LPIR >46 (sensitivity: 75.9 %, specificity: 70.0%). We conclude that NMR-derived LPIR may be an appropriate index to assess insulin resistance in South Asians.

MON-LB113 Insulin Resistance in Type 1 Diabetes Managed With Metformin (INTIMET): Rationale and Study Design of a Randomised Placebo-Controlled Trial

Background: Insulin resistance is an under-recognised cardiovascular risk factor in type 1 diabetes (T1D). Individuals with T1D exhibit insulin resistance relative to those without diabetes. In T1D, tissue-specific insulin resistance (muscle, hepatic, adipose) is likely to partly drive increased cardiovascular risk. Adjunctive metformin improves muscle insulin sensitivity in T1D adolescents, but factors that predict responsiveness remain unknown.Objective: To report the rationale and design of the INTIMET study, a double-blind randomised, placebo-controlled trial of metformin in T1D.Methods: Forty adults aged 20-50 years with T1D, and 20 age- gender- and BMI- matched non-diabetic controls will be studied. T1D inclusion criteria are diagnosis > 10 years, HbA1c 9.5% and fasting C-peptide < 0.3nmol/L. Liver and muscle insulin sensitivity will be determined by the 2-stage hyperinsulinemic (20 and 60 mUm2)-euglycemic (5.5 mmol/L) clamp method with deuterated glucose. Subjects with T1D will be randomised to metformin extended-release 1500mg/d or matched placebo for 26 weeks. The primary endpoint is the change in hepatic insulin sensitivity, measured by suppression of endogenous glucose production (EGP) with the low-dose insulin clamp. Secondary endpoints include change in muscle and adipose tissue insulin sensitivity, arterial stiffness, HbA1c, glucose variability, frequency of hypoglycemia, insulin dose, anthropometry, body composition, lipid profile, liver fat and stiffness. Conclusion: The INTIMET study will quantify muscle, liver and adipose insulin-resistance in T1D, determine whether metformin is effective in improving insulin resistance in T1D and identify factors that predict metformin-responsiveness.The trial is registered (Australian New Zealand Clinical Trial Registry, ACTRN12619001440112) and is actively recruiting in Sydney, Australia.

GPx3 dysregulation impacts adipose tissue insulin receptor expression and sensitivity

Insulin receptor signaling is crucial for white adipose tissue (WAT) function. Consequently, lack of insulin receptor (IR) in WAT results in a diabetes-like phenotype. Yet, causes for IR downregulation in WAT of patients with diabetes are not well understood. By using multiple mouse models of obesity and insulin resistance, we identify a common downregulation of IR with a reduction of mRNA expression of selenoproteins Txnrd3, Sephs2, and Gpx3 in gonadal adipose tissue. Consistently, GPX3 is also decreased in adipose tissue of insulin-resistant and obese patients. Inducing Gpx3 expression via selenite treatment enhances IR expression via activation of the transcription factor Sp1 in 3T3-L1 preadipocytes and improves adipocyte differentiation and function. Feeding mice a selenium-enriched high-fat diet alleviates diet-induced insulin resistance with increased insulin sensitivity, decreased tissue inflammation, and elevated IR expression in WAT. Again, IR expression correlated positively with Gpx3 expression, a phenotype that is also conserved in humans. Consequently, decreasing GPx3 using siRNA technique reduced IR expression and insulin sensitivity in 3T3-L1 preadipocytes. Overall, our data identify GPx3 as a potentially novel regulator of IR expression and insulin sensitivity in adipose tissue.

Individual and cohort-specific gut microbiota patterns associated with tissue-specific insulin sensitivity in overweight and obese males

A growing body of evidence suggests that the human gut microbiota plays a role in the development of obesity and related metabolic diseases. However, there is little consensus between studies, which could be due to biological as well as technical variation. In addition, little human data are available to investigate whether tissue-specific insulin sensitivity is related to specific microbial patterns. We examined this relation in two independent cohorts of overweight and obese pre-diabetic men, using phylogenetic microarray data and hepatic, peripheral and adipose tissue insulin sensitivity that were determined by a two-step hyperinsulinemic-euglycemic clamp with [6,6-2H2]-glucose tracer infusion. Despite a prominent subject-specific microbiota, we found significant associations of microbial taxa with tissue-specific insulin sensitivity using regression analysis. Using random forests we found moderate associations with other measures of glucose homeostasis in only one of the cohorts (fasting glucose concentrations AUC = 0.66 and HbA1c AUC = 0.65). However, all findings were cohort-specific due to pronounced variation in microbiota between cohorts, suggesting the existence of alternative states for dysbiosis in metabolic syndrome patients. Our findings suggest individual or group related dynamics, instead of universal microbiota signals, related to the host when the overweight or obese state has already developed and argue that care should be taken with extrapolating significant correlations from single cohorts, into generalized biological relevance.

Ablation of uncoupling protein 1 causes opposing changes of glucose uptake in brown and brite fat compatible with regulation of Glut 4 gene expression

BackgroundRecruitment and activation of uncoupling protein 1 – dependent thermogenesis in brown and brite fat is a candidate mechanism to promote negative energy balance and improve systemic glucose homeostasis. Non‐shivering thermogenesis mediated by UCP1 is mainly sustained by fatty acid oxidation and to lesser extent by glucose. Glucose supply, however, is essential to run serial and parallel metabolic pathways involved in thermogenesis, including glycolysis, glyceroneogenesis, anabolic bolstering of the citric acid cycle and de novo lipogenesis. Norepinephrine release in the cold stimulates glucose uptake via GLUT1 to support thermogenesis, while insulin stimulates uptake via GLUT4 for the storage of glycogen and triglyceride. It is unclear, however, whether glucose uptake depends on the presence of UCP1.ObjectiveWe aimed to quantify the effect of UCP1 ablation on insulin sensitivity, glucose tolerance and glucose uptake in brown and brite adipose tissues of mice fed either low, intermediate or high fat diets.MethodsWe assessed insulin sensitivity and oral glucose tolerance, and measured 2‐deoxyglucose uptake in different brown and white fat depots of UCP1‐KO and WT mice (B6 and 129 background) housed at thermoneutral temperature. Mice were fed low, intermediate and high fat diets. Transcriptomes of interscapular brown fat and inguinal brite fat were sequenced (RNA‐SEQ) and subjected to bioinformatic analysis.Results and DiscussionIn UCP1‐KO mice fed intermediate and high fat diets, body weight trajectories and body fat mass were rather unchanged or decreased. They rather showed reduced metabolic efficiency when fed the high fat diet, thus challenging a role of UCP1‐dependent thermogenesis in diet‐induced obesity resistance. Oral glucose tolerance, when analyzed as incremental area under the curve, was robustly impaired in UCP1‐KO mice fed intermediate and high fat diets, whereas insulin sensitivity was unchanged. In WT mice, brown fat showed the highest mass‐specific glucose uptake, with total uptake in the interscapular brown fat depot attaining up to 70% of the amount of glucose uptake measured in liver. Glucose uptake in UCP1‐KO mice was reduced in different brown fat depots, irrespective of diet. In contrast, glucose uptake was increased in inguinal brite fat of UCP1‐KO mice fed low fat diet. This increase was attenuated in mice fed intermediate or high fat diets. These differential genotype effects on glucose uptake in brown and brite fat were strongly associated with corresponding changes in Glut4 expression. Our results demonstrate a role of UCP1 in post‐prandial glucose homeostasis, most likely due to the reduced uptake into brown fat. Increased glucose uptake in inguinal brite fat of UCP1‐KO further corroborates the recruitment of alternative UCP1‐independent thermogenic capacity. We conclude that UCP1 is a modulator of adipose tissue glucose uptake and systemic glucose homeostasis.Support or Funding InformationThis work was supported by the EU FP7 project DIABAT (HEALTH‐F2‐2011‐278373), the Deutsche Forschungsgemeinschaft (KL973/13‐1, NUTRIBRITE) and the Else Kröner‐Fresenius Stiftung (EKFS).

Probiotic property and biological activities of Bifidobacterium animalis subsp. lactis TISTR 2591 isolated from Thai population

Bifidobacterium animalis subsp. lactis TISTR 2591 (B. L TISTR) isolated from Thai newborn babies and identified regarding 16S rDNA analysis. Its probiotic property was assessed on hemolytic activity, antibiotic susceptibility, gastric acid and bile resistance capacity, antimicrobial activity and adhesion ability. The biological properties of B. L TISTR were evaluated on blood metabolic parameters (cholesterol, glucose and insulin levels) and metabolic genes expression. The obtained results indicated that B. L TISTR has no hemolytic activity. Its adhesion ability to intestinal epithelium of Caco-2 and HT-29 cell lines is greater than that of the two commercial strains (B. lactis and L. reuteri). No antibiotic resistance property of B. L TISTR was found on eight antibiotics tested. Moreover, it possesses antimicrobial activity against twelve pathogenic bacteria covering seven intestinal pathogens, two oral pathogens and three skin pathogens. It was found that B. L TISTR could induce insulin sensitivity in adipose tissue that was related with reducing glucose. Also, it was shown that cholesterol level in plasma B. L TISTR fed mice decreased significantly. Expression of three metabolic genes including Srebp-1c, Glut4 and Ucp1 was found. These three genes are involved in gluconeogenic control, insulin sensitivity and cholesterol and fatty acid metabolism, respectively. We examined Il10 and Nos2 expression in Peyer’s patches from intestinal and found an induction of Il10 expression. We also found that Nos2 expression decreased in B. L TISTR fed mice. These observations suggest that B. L TISTR may improve immune system and reduce inflammation activity which in turn providing prevention of intestinal inflammation.

Shape of the glucose response curve during an oral glucose tolerance test is associated with insulin clearance and muscle insulin sensitivity in healthy non-obese men.

Individuals with a monophasic glucose response curve (GRC) during a 75‐g oral glucose tolerance test have a higher risk for type 2 diabetes than those with a biphasic GRC. However, no studies have addressed the association between GRC type and insulin clearance. Thus, we studied 49 healthy non‐obese Japanese men. We divided study participants into the monophasic or biphasic group based on the shape of their GRC. We evaluated tissue‐specific insulin sensitivity and insulin clearance using a two‐step hyperinsulinemic‐euglycemic clamp. The monophasic group had more visceral fat, lower insulin clearance and lower muscle insulin sensitivity than the biphasic group, whereas liver and adipose tissue insulin sensitivity, and insulin secretion were comparable. In conclusion, healthy non‐obese men with a monophasic GRC have lower insulin clearance and muscle insulin sensitivity.

Effect of Sleep Restriction on Adipose Tissue and Skeletal Muscle Insulin Sensitivity

Effect of Sleep Restriction on Adipose Tissue and Skeletal Muscle Insulin Sensitivity

Ovine prenatal growth-restriction and sex influence fetal adipose tissue phenotype and impact postnatal lipid metabolism and adiposity in vivo from birth until adulthood.

Adipose tissue development begins in utero and is a key target of developmental programming. Here the influence of nutritionally-mediated prenatal growth-restriction on perirenal adipose tissue (PAT) gene expression and adipocyte phenotype in late fetal life was investigated in both sexes in an ovine model. Likewise circulating leptin concentrations and non-esterified fatty acid (NEFA) and glycerol responses to glucose challenge were determined in relation to offspring adiposity at key stages from birth to mid-adult life. In both studies' singleton-bearing adolescent sheep were fed control or high nutrient intakes to induce normal or growth-restricted pregnancies, respectively. Fetal growth-restriction at day 130 of gestation (32% lighter) was characterised by greater body-weight-specific PAT mass and higher PAT expression of peroxisome proliferator-activated receptor gamma (PPARɤ), glycerol-3-phosphate dehydrogenase, hormone sensitive lipase (HSL), insulin-like growth factor 1 receptor, and uncoupling protein 1. Independent of prenatal growth, females had a greater body-weight-specific PAT mass, more multilocular adipocytes, higher leptin and lower insulin-like growth factor 1 mRNA than males. Growth-restricted offspring of both sexes (42% lighter at birth) were characterised by higher plasma NEFA concentrations across the life-course (post-fasting and after glucose challenge at 7, 32, 60, 85 and 106 weeks of age) consistent with reduced adipose tissue insulin sensitivity. Circulating plasma leptin correlated with body fat percentage (females>males) and restricted compared with normal females had more body fat and increased abundance of PPARɤ, HSL, leptin and adiponectin mRNA in PAT at necropsy (109 weeks). Therefore, prenatal nutrient supply and sex both influence adipose tissue development with consequences for lipid metabolism and body composition persisting throughout the life-course.

Loss of voltage-gated proton channel Hv1 leads to diet-induced obesity in mice

ObjectiveThe voltage-gated proton channel Hv1 has been proposed to mediate NADPH oxidase (NOX) function by regulating intracellular pH during respiratory bursts. In our previous work, we showed that Hv1 is...

Differences in the link between insulin sensitivity and ectopic fat in men of Black African and White European ethnicity.

In men of black west African (BAM) and white European (WEM) ethnicity, we aimed to (1) compare adipose tissue, peripheral and hepatic insulin sensitivity and (2) investigate associations between ectopic fat and insulin sensitivity by ethnicity. In overweight BAM (n = 21) and WEM (n = 23) with normal glucose tolerance, we performed a two-step hyperinsulinaemic-euglycaemic clamp with infusion of [6,6 2H2]-glucose and [2H5]-glycerol to measure whole body, peripheral, hepatic and adipose tissue insulin sensitivity (lipolysis). Visceral adipose tissue (VAT), intrahepatic lipids (IHL) and intramyocellular (IMCL) lipids were measured using MRI and spectroscopy. Associations between insulin sensitivity and ectopic fat were assessed using Pearson's correlation coefficient by ethnicity and regression analysis. There were no ethnic differences in whole body or tissue-specific insulin sensitivity (all P > 0.05). Suppression of lipolysis was inversely associated with VAT and IHL in WEM but not BAM (VAT: WEM r = -0.68, P < 0.01; BAM r = 0.07, P = 0.79. IHL: WEM r = -0.52, P = 0.01; BAM r = -0.12, P = 0.63). IMCL was inversely associated with skeletal muscle insulin sensitivity in WEM but not BAM (WEM r = -0.56, P < 0.01; BAM r = -0.09, P = 0.75) and IHL was inversely associated with hepatic insulin sensitivity in WEM but not BAM (WEM r = -0.53, P = 0.02; BAM r = -0.13, P = 0.62). Ectopic fat deposition may play a lesser role in reducing insulin sensitivity in men of black African ethnicity and may not be driven by lipolysis. Resistance to storing VAT, IHL and IMCL may enable men of black African ethnicity to maintain comparable insulin sensitivity to white Europeans.