bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mild Physiologic Hyperglycemia Impairs Beta-Cell Function and Induces Insulin Resistance in Healthy Normal Glucose Tolerant Subjects
Authors: MEROVCI AURORA , MALDONADO CORCHADO ENRIQUE R. , TRIPATHY DEVJIT , DEFRONZO RALPH A. 
Published: June 2018

The aim of the present study was to evaluate effect of a physiologic increase (+45 mg/dl) in plasma glucose concentration on insulin secretion in healthy NGT individuals. 20 NGT subjects: 12 without family history of T2DM (FH-) (9M/3F, age = 50± 4 years, BMI = 27 ± 1 kg/m2) and 8 with FH (FH+) (4M/4F, Age = 48±2, BMI = 26±1) received an OGTT and 2-step hyperglycemic (+125 and +300 mg/dl) clamp (duration of each step = 80 minutes) followed by IV arginine (5g) bolus. The acute insulin response (AIR0-10min), 2nd phase (SP) insulin secretion (IR) (SPIS10-80 and SIS90-160 minutes during each hyperglycemic step and following arginine (AIRArg) were assessed. Insulin sensitivity was assessed as the glucose infusion rate/steady state plasma insulin (M/I) during the hyperglycemic clamp. FPG concentration increased from 97±4 to 140±4 mg/dl for 48 hours by a variable IV glucose infusion. First phase insulin secretion (0-10 min) and 2nd phase insulin secretion (10-80 and 90-60 min) increased by 59% and 78%, respectively, following chronic glucose infusion while insulin sensitivity (M/I) during both hyperglycemic clamp steps declined (15± 3.5 to 12±2.8 and 20.8 ± 4.7 to 8.1 ± 2.0, both p&lt;0.02). Consequently, the insulin secretion/insulin resistance (disposition) index declined by 85± 18% (1st clamp step) and 81±45% (2nd clamp step) (both p&lt;0.05) following chronic glucose infusion. Similar changes were observed when indices of insulin secretion were measured using C-peptide. There was no difference in the effect of chronic glucose infusion on insulin secretion and insulin sensitivity between subjects with and without FH of T2DM. These results demonstrate that: (i) sustained physiologic hyperglycemia impairs insulin sensitivity (glucotoxicity); (ii) increases absolute insulin secretion; (iii) impairs beta cell function as measured with the disposition index (glucotoxicity).

Disclosure
A. Merovci: None. E.R. Maldonado Corchado: None. D. Tripathy: None. R.A. DeFronzo: Speaker's Bureau; Self; AstraZeneca, Novo Nordisk Inc.. Advisory Panel; Self; AstraZeneca, Novo Nordisk Inc., Janssen Pharmaceuticals, Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Elcelyx Therapeutics, Inc., Intarcia Therapeutics, Inc.. Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Takeda Pharmaceuticals U.S.A., Inc..
Insulin Resistance Impairs Cognitive Performance Even in Healthy Subjects at Risk for Diabetes Mellitus
Authors: SORICE GIAN PIO , IMPROTA ILARIA , MEZZA TERESA , GRIONI SARA , IACOBUCCI GIOVANNA MASONE , MOFFA SIMONA , MARI ANDREA , MARRA CAMILLO , GIACCARI ANDREA 
Published: June 2018

Increasing scientific evidences support the hypothesis that type 2 diabetes mellitus (T2D) increases the risk of developing dementia and cognitive impairment. Experimental data, although still conflicting, show that insulin resistance (IR) is able to influence cognitive performance (CP). The objective of our study, therefore, was to verify the relationship between insulin resistance and cognitive performance (PC) in subjects at risk for DM2.
For this reason 134 (111 F) volunteers, healthy at risk for diabetes mellitus (overweight and/or fasting hyperglycemia and/or family history for T2D), 39.0±12.3 year old, BMI 25.2±4.8 kg/m2, were enrolled; they underwent to metabolic study (OGTT for glycemia, insulinemia and c-peptide), and neuropsychological tests to evaluate global cognitive function, verbal learning, memory, visual attention and executive functions.
The results of the neuropsychological tests were subsequently normalized by age and education; each test was standardized with a score from 0 (worst) to 4 (best performance). The equivalent scores of each test were summed to obtain a composite endpoint (Cognitive Performance Index), from 0 to 16, with increasing gradient for better CP.By dividing the subjects recruited into quartiles on the basis of PCI, the IR indexes gradually worsened as PCI became worse, particularly HOMA-IR, Matsuda, basal insulin secretion and basal insulin clearance (p &lt;0.04, &lt;0.005, &lt;0.and &lt;0.001, respectively). After multiple regression analysis, basal insulin secretion was more related to CP worsening. No correlation with fasting blood glucose, 1 hour and 2 hours glucose after oral load, was found.
These data seem to reinforce the hypothesis that insulin resistance, independently of glycemia, can worsen performance even in Health subjects, at risk for diabetes mellitus.

Disclosure
G. Sorice: None. I. Improta: None. T. Mezza: None. S. Grioni: None. G. Masone Iacobucci: None. S. Moffa: None. A. Mari: None. C. Marra: None. A. Giaccari: Advisory Panel; Self; Sanofi-Aventis. Speaker's Bureau; Self; AstraZeneca, Merck Sharp & Dohme Corp., Amgen Inc..
Hepatic Lipid Profiling in Fatty Liver Disease—Degree of Saturation Matters
Authors: ERICKSON MELISSA L. , HAUS JACOB M. , FLASK CHRIS , KIRWAN JOHN P. 
Published: June 2018

Introduction: Hepatic lipids can take on several storage forms, which vary by degree of saturation. The health consequences of hepatic lipids may vary by storage type, in that polyunsaturated lipids may be favorable, while saturated lipids may be detrimental. The purpose of this study was to determine if the degree of hepatic lipid saturation is related to hallmark characteristics of obesity-related nonalcoholic fatty liver disease, including low exercise capacity and insulin resistance.
Methods: Hepatic lipid profiles were measured using 1H-MRS in 30 adults (55 ± 13.4 years, 31 ± 5.5 kg/m2). Methyl, allylic, methylene, and diallylic peaks were quantified. Hepatic lipids were categorized by storage form, including polyunsaturation, unsaturation, and saturation indices. Explored health correlates include exercise capacity, 40 mU/m2 euglycemic-hyperinsulinemic clamps, and abdominal CT scans.
Results: 20 participants met the diagnostic criteria for nonalcoholic fatty liver disease (total hepatic fat &gt; 5%). Hepatic polyunsaturation index was positively related to absolute maximal oxygen uptake (r=0.41, P=0.04). In addition, hepatic saturation index was inversely related to clamp-derived skeletal muscle insulin sensitivity (r=-0.48, P=0.007).
Discussion/Conclusion: We found that the hepatic polyunsaturation index was positivity related to exercise capacity, independent of body weight. Conversely, saturation index was inversely related to insulin sensitivity. These data show that the health consequences of hepatic fat vary by storage type. Insulin resistance is associated with a higher degree of saturation and a consequential lower degree of polyunsaturation. Thus, effective treatment strategies for nonalcoholic fatty liver disease should not only aim to reduce total hepatic lipid content, but also promote a shift in storage type, from saturation to polyunsaturation, in order to maximize metabolic benefit.

Disclosure
M.L. Erickson: None. J.M. Haus: None. C. Flask: None. J.P. Kirwan: None.
Liver-Specific Overexpression of NOS1AP Alleviates Hepatic Insulin Resistance in Obese Mice
Authors: WANG CHEN , MU KAIDA , ZHAO TIANXUE , ZHU HUI , JIA WEIPING 
Published: June 2018

Objective: Nitric oxide synthase 1 adaptor protein (NOS1AP) controls a number of different signaling complexes. We reported previously that the NOS1AP SNP rs12742393 was associated with type 2 diabetes (T2D). T2D and nonalcoholic fatty liver disease (NAFLD) are closely associated, in which NAFLD contributes to the development of liver insulin resistance in T2D. Thus, we investigated whether NOS1AP plays a role in regulating hepatic insulin sensitivity.
Methods: Liver-specific NOS1AP overexpression and knockout mice were fed a high-fat diet (HFD).
Results: NOS1AP protein is highly expressed in mouse liver. Its expression is downregulated in livers of obese rodents. Overexpression of NOS1AP in liver of ob/ob or HFD-induced obese mice improved pyruvate and/or glucose and insulin tolerance, and attenuated liver lipid accumulation in these mice. Conversely, liver specific deletion of NOS1AP impaired pyruvate, glucose and insulin tolerance in the mice, and increased lipid accumulation in the liver. Moreover, overexpression of NOS1AP resulted in reduced expression of Pck1 and increased insulin-induced p-Akt in HepG2 cells. Furthermore, the insulin sensitizing effect of NOS1AP could be mimicked by overexpression of C-terminal domain of NOS1AP in ob/ob mice.
Conclusion: Our data demonstrate a novel role of NOS1AP in regulating hepatic insulin sensitivity and lipid accumulation in liver, which implicates NOS1AP a therapeutic target for treatment of NAFLD and prevention of T2D.

Disclosure
C. Wang: None. K. Mu: None. T. Zhao: None. H. Zhu: None. W. Jia: None.
A Novel Role for SerpinB1, a Protease Inhibitor, in Hepatic Biology
Authors: ORIME KAZUKI , DE JESUS DARIO F. , KULKARNI ROHIT 
Published: June 2018

SerpinB1, a protease inhibitor that is secreted from the liver in response to insulin resistance, was recently reported to promote pancreatic β cell proliferation. We focused on investigating the significance of SerpinB1 in the liver to gain insights into its role in regulating whole body metabolism. We determined SerpinB1 gene expression in multiple metabolic tissues harvested under fasting or fed states from ∼34-week-old male Liver-specific insulin receptor knockout (LIRKO) mice and littermate controls. While in controls SerpinB1 expression was reduced by ∼50% after feeding when compared to the fasting state, (P=0.02, n=4-5), the LIRKOs, in contrast, exhibited a 2.3-fold higher (P=0.01, n=5-6) expression in the fed vs. fasting states and the higher levels were consistent with earlier observations in the LIRKO livers. We next took advantage of the availability of liver samples from 18 to 24-week-old male SerpinB1 KO mice and littermate controls and subjected them to RNA-sequencing. As expected, SerpinB1 gene expression was absent in the KO samples, and interestingly, was associated with a significant decrease in gene expression related to cell cycle, NF-kappa B signaling, and inflammatory pathways. Independent validation of these data by RT-qPCR confirmed a decrease in cell cycle-related genes such as Ccna2 (-60%, P=0.04), Ccnb2 (-54%, P=0.04), Ccnd1 (-46%, P=0.03), and Ccne1 (-51%, P=0.07), and the cell proliferation marker, Mki67 (-60%, P=0.00) (n=5). Furthermore, knockdown of SerpinB1 in the human hepatocyte cell line, HepG2, exhibited significantly decreased expression of Ccnb1 (-36%, P=0.01), Ccnb2 (-44%, P=0.00), Ccne1 (-21%, P=0.00), MKi67 (-30%, P=0.00), and MCM2 (-29%, P=0.00) genes, and increased expression of P21 (+165%, P=0.00) (n=3 for control vs. knockdown groups). These novel data implicate endogenous SerpinB1 in cell proliferation in hepatocytes and warrant further investigation of its role in hepatocyte function and the overall impact on glucose homeostasis.

Disclosure
K. Orime: None. D.F. De Jesus: None. R. Kulkarni: None.
Liver-Specific siRNA Inhibition of Class 2a Histone Deacetylases (HDACs) Reduces Expression of Genes Regulating Gluconeogenesis in Primary Human and Mouse Hepatocytes, but Not in Mice
Authors: GÖRGENS SVEN W. , RAICHUR SURYAPRAKSH , WOHLFART PAULUS , BRUNNER BODO , TENNAGELS NORBERT , BIELOHUBY MAXIMILIAN 
Published: June 2018

Gene expression control by histone-deacetylases Class 2a (HDACs 4,5,7,9) has been demonstrated to be involved in the negative regulation of hepatic gluconeogenesis and consequently inhibition of HDACs was shown to result in improved glucose and pyruvate tolerance in rodent type 2 diabetes (T2D) models. However, pan-inhibition of HDACs in all tissues leads also to severe side effects in various tissues, excluding this approach for treatment of T2D. Here, we have investigated in vitro and in vivo safety and efficacy of a liver-selective HDAC knock-down via single or combinatorial siRNAs for HDAC 4, 5 or 7. In primary mouse and human hepatocytes, specific siRNAs directed against HDAC 4, 5 or 7, as well as their combination led to a selective knock-down of the respective target gene(s) by about 80-90%, which paralleled with a significant reduction of genes involved in the regulation of gluconeogenesis. These siRNAs were administered in a liver-specific lipid-particle formulation for treatment of healthy C57BL/6J mice. Mice received five intravenous injections with either PBS, a control siRNA, one of the respective silencing siRNAs (0.75mg/kg) or all possible dual or triple combinations for 25 days. Quantitative real-time PCR demonstrated that siRNA treatment led to a significant downregulation of the respective HDACs in the liver. However no reduction of gluconeogenic genes (PCK1 and G6PC) was detected. Consequently, also no improvement in intraperitoneal pyruvate tolerance test (PTT) could be observed. In addition, no significant differences in fasting blood glucose or plasma insulin were observed between treatment groups.
In summary, although active in cellular systems, liver-targeted siRNA knockdown of class 2a HDACs did not result in a clear inhibition of genes regulating gluconeogenesis in healthy mice suggesting no clear path forward for development of this approach for treatment of T2D.

Disclosure
S.W. Görgens: Employee; Self; Sanofi-Aventis Deutschland GmbH. S. Raichur: None. P. Wohlfart: Employee; Self; Sanofi-Aventis Deutschland GmbH. B. Brunner: Employee; Self; Sanofi. N. Tennagels: Employee; Self; Sanofi R&D. Stock/Shareholder; Self; Sanofi. M. Bielohuby: Employee; Self; Sanofi-Aventis Deutschland GmbH, Sanofi R&D.
Genetic Ablation of Liver CPT-1A Gene Protects Mice against High-Fat Diet–Induced Obesity and Insulin Resistance
Authors: WU DONGHAI 
Published: June 2018

Carnitine palmitoyl transferase 1A (CPT-1A) catalyzes the transfer of the acyl group of long-chain fatty acid-CoA moiety onto carnitine, an essential step for the uptake of long-chain fatty acids and their subsequent beta-oxidation in the mitochondrion. It is the rate-limiting step in beta-oxidation and is highly expressed in the liver where it plays an important role in triglyceride metabolism. The physiological consequences of CPT-1A deficiency in liver, however, are yet to be reported. In this study, we have generated mouse model with liver specific deletion of CPT-1A gene. We found that deletion of CPT-1A in liver caused an increased triglyceride content in liver and decreased epididymal adipose tissue weight compared with control mice under high fat diet feeding conditions. RNA-seq analysis between livers of CPT-1A knockout vs. wild type mice revealed altered expression of many metabolic pathways such as steroid hormone biosynthesis and PPAR signaling pathways as well as some novel hepatokines. Further analysis of the significance of these changes is under way but the data so far suggest that a pharmacological agent that alters hepatic fatty acid oxidation (perhaps acting on CPT-1A) could provide a novel approach to target nonalcohol fatty liver disease (NAFLD).

Disclosure
D. Wu: None.
Loss of Insulin/IGF-1 Receptors in Muscle Coordinately Downregulates Mitochondrial Metabolism and Alters Mitophagy via Foxo Transcription Factors
Authors: BHARDWAJ GOURAV , PENNIMAN CHRISTIE M. , SUAREZ BELTRAN PABLO A. , FOSTER COLLIN M. , O'NEILL BRIAN T. 
Published: June 2018

Diabetes is associated with decreased muscle strength and energy production. There is a strong association between muscle insulin resistance and mitochondrial abnormalities, but cause/effect remains hotly debated. Recently, we showed that insulin receptor (IR) and IGF-1 receptor (IGF1R) signaling controls muscle atrophy by FoxO1/3/4-dependent regulation of autophagy. To directly test the roles of IR, IGF1R, and FoxO signaling on muscle metabolism and mitochondrial autophagy (mitophagy) we measured mitochondrial function in mice lacking IR (M-IR-/-), both IR/IGF1R (MIGIRKO), or IR/IGF1R/FoxO1/3/4 (QKO) in muscle. RNA seq analysis revealed decreases in multiple mitochondrial pathways from M-IR-/- and MIGIRKO muscle, including OXPHOS. Respiratory capacity and ATP production were decreased in mitochondria and soleus fibers isolated from M-IR-/- and MIGIRKO mice using complex I substrates. These decreases in OXPHOS and mitochondrial function were normalized when FoxOs were deleted in QKO mice. MIGIRKO muscle showed decreased PINK1 (mitophagy protein) and increased LC3II/I ratio, indicating changes in respiration and mitophagy occurred together. To determine if this was cell autonomous, C2C12 myotubes were pre-treated with insulin and/or CCCP (an uncoupler and mitophagy-inducer), and assayed for respiration. Insulin increased respiration and PINK1 levels after 24 hours. Four hour CCCP pre-treatment reduced basal respiration and increased LC3II/I which were partially, but significantly, rescued with insulin in C2C12 myotubes. PINK1 was also decreased in primary myotubes with acute deletion of IR/IGF1R. Thus, loss of IR/IGFR signaling in skeletal muscle directly reduces mitochondrial respiratory capacity and alters mitophagy, which is regulated by FoxO transcription factors.

Disclosure
G. Bhardwaj: None. C.M. Penniman: None. P.A. Suarez Beltran: None. C.M. Foster: None. B.T. O'Neill: None.
A Role for Macrophage Adenosine 2A Receptor in Diet-Induced Nonalcoholic Fatty Liver Disease
Authors: ZHOU JING , LI HONGGUI , LUO XIANJUN , MA LINQIANG , WU CHAODONG 
Published: June 2018

Recent evidence suggests that adenosine 2A receptor (A2AR) exerts a protective role in NAFLD. However, the role of the A2AR in macrophages in NAFLD pathophysiology remains unknown. In the present study, hepatic inflammation and fat deposition were examined in myeloid cell-specific A2AR-deficient mice and control mice fed a HFD for 12 weeks. In addition, bone marrow cells were isolated from global and/or myeloid cell-specific A2AR-deficient mice and differentiated into macrophages (BMDM) for inflammatory analysis and for macrophage-hepatocyte co-cultures. Upon HFD feeding, the activity of JNK p46 and NFκB p65 and the mRNA levels of proinflammatory cytokines such as TNFα, IL-1β, and IL-6 in livers of myeloid cell-specific A2AR-defcient mice were significantly higher than their respective levels in livers of control mice. These increases were accompanied with increased severity of diet-induced hepatic steatosis, indicated by the results from liver histology and by elevated levels of liver triglycerides. When BMDM were analyzed for inflammatory activation, the phosphorylation states of JNK p46 and NFκB p65 and the production of proinflammatory cytokines in A2AR-deficient BMDM were significantly higher than their respective levels in control BMDM. Moreover, in macrophage-hepatocyte co-culture systems, hepatocytes co-cultured with A2AR-deficient BMDM revealed significant increases in TNFα, IL-1β, and IL-6 mRNAs in relative to hepatocytes co-cultured with control BMDM. Additionally, hepatocytes co-cultured with A2AR-deficient BMDM accumulated much more fat upon palmitate stimulation than hepatocytes co-cultured with control BMDM. Taken together, these results suggest that the inflammatory status of macrophages can be altered by A2AR in a manner to critically determine the development of NAFLD. Moreover, targeting A2AR to suppress inflammation may be a viable preventive and/or therapeutic approach for inflammation-associated diseases including NAFLD.

Disclosure
J. Zhou: None. H. Li: None. X. Luo: None. L. Ma: None. C. Wu: None.
Integration of BCAA and Lipid Metabolism by the BCKDH Kinase and Phosphatase
Authors: WHITE PHILLIP J. , MCGARRAH ROBERT W. , GRIMSRUD PAUL A. , YANG WEN-HSUAN , ZHANG GUO-FANG , HALDEMAN JONATHAN M. , ARLOTTO MICHELLE , ILKAYEVA OLGA , WYNN RICHARD M. , CHUANG DAVID T. , NEWGARD CHRISTOPHER B. 
Published: June 2018

Strong associations exist between branched chain amino acids (BCAA) and dysregulated glucose and lipid metabolism, but underlying mechanisms are not well understood. One factor contributing to elevated BCAA in obesity is inhibitory phosphorylation of the branched chain keto-acid dehydrogenase complex (BCKDH) in liver. We studied the impact of modulating the activity of the BCKDH kinase (BDK) and phosphatase (PPM1K) on amino acid, glucose and lipid metabolism in Zucker fatty rats (ZFR). Daily administration of a selective inhibitor of BDK, BT2 (20mg.kg-1, IP), for one week or expression of a recombinant adenovirus overexpressing PPM1K significantly lowered BCAA and branched chain keto acid (BCKA) levels in ZFR. Remarkably, these effects were accompanied by strong lowering of liver triacylglycerides and improved glucose tolerance in the absence of weight loss. Proteomics analysis of liver samples from these studies revealed that both inhibition of BDK with BT2 and adenoviral mediated overexpression of PPM1K results in reduced phosphorylation of the lipogenic enzyme ATP-citrate lyase (ACL) on its regulatory serine 454. Phosphorylation of ACL on this site is activating. Sequence analysis revealed the presence of a canonical BDK phosphorylation motif surrounding ser454 in ACL and incubation of ACL with purified BDK resulted in ACL phosphorylation in vitro. Furthermore, adenovirus-mediated overexpression of BDK increased ACL phosphorylation and activated de novo lipogenesis in liver of lean Wistar rats. Together these studies reveal a novel regulatory function for BDK and PPM1K in integration of BCAA and lipid metabolism. Moreover, we show that modulation of this node provides broad protection against metabolic abnormalities associated with obesity.

Disclosure
P.J. White: None. R.W. McGarrah: None. P.A. Grimsrud: None. W. Yang: None. G. Zhang: None. J.M. Haldeman: None. M. Arlotto: None. O. Ilkayeva: None. R.M. Wynn: None. D.T. Chuang: None. C.B. Newgard: Advisory Panel; Self; Eli Lilly and Company. Research Support; Self; Eli Lilly and Company.
Estrogen Improves Insulin Sensitivity and Suppresses Hepatic Glucose Production via the Transcription Factor Foxo1
Authors: YAN HUI , ZHOU FENGHUA , YANG WANBAO , PAN QUAN , SHEN ZHENG , HAN GUICHUN , ALLRED KIMBERLY , ALLRED CLINTON , XU YONG , GUO SHAODONG 
Published: June 2018

Premenopausal women exhibit enhanced insulin sensitivity and reduced incidence of type 2 diabetes compared with age-matched men, but this advantage disappears after menopause with disrupted glucose homeostasis, in part, owing to a reduction in circulating 17β-estradiol (E2). Fasting hyperglycemia, a feature of diabetes mellitus, is largely derived from dysregulation of hepatic glucose production (HGP), in which hyper-activated Foxo1 induces transcription of genes coding gluconeogenic enzymes. We investigated the E2 action on the regulation of glucose hemostasis in male and ovariectomized (OVX) female of control and liver-specific Foxo1 knockout (L-F1KO) mice, and sought to understand the mechanism by which E2 regulates gluconeogenesis via the interaction with liver Foxo1. E2 subcutaneous implant led to decreased fasting blood glucose and improvement of insulin sensitivity in both male and OVX female mice in parallel with the suppression of gluconeogenesis and hepatic gluconeogenic gene expression, including glucose 6-phosphatase (G6pase) and phosphoenolpyruvate carboxykinase 1 (Pck1). Importantly, these effects of E2 were only observed in control mice but disrupted in L-F1KO mice. Moreover, suppression of HGP and gluconeogenesis by E2 only occurred in hepatocytes isolated from control mice and we confirmed that Foxo1 was required for the E2 action on gluconeogenesis. E2 suppressed Foxo1 via activation of ERα and phosphorylation of Akt, while inhibition of both ERα and Akt signaling abolished the effect of E2 on gluconeogenesis. Collectively we demonstrated that the activation of ERα-Akt-Foxo1 signaling serves as an important mechanism of estrogen in control of glucose homeostasis. These results may help explain the gender difference in the incidence of type 2 diabetes and suggest an approach to target ERα to modulate glucose metabolism in diabetic patients.

Disclosure
H. Yan: None. F. Zhou: None. W. Yang: None. Q. Pan: None. Z. Shen: None. G. Han: None. K. Allred: None. C. Allred: None. Y. Xu: None. S. Guo: None.