bluuebunny/crossref_metadata_2025 huggingface dataset:
1936-P: Muscle Ischemia Impairs Insulin-Mediated Microvascular Recruitment
Authors: WANG NASUI , LIU ZHENQI
Published: June 2019

Diabetes predisposes patients to peripheral artery disease (PAD). Muscle microvasculature plays a critical role in maintaining muscle function and health by delivering oxygen, nutrients and hormones to myocytes. Insulin dilates precapillary arterioles to increase muscle perfusion. To define the impact of ischemia to muscle microvascular perfusion and microvascular response to insulin, adult male rats were subject to hind limb ischemic surgery. Total hind limb blood flow was determined using laser Doppler blood flowmetry and muscle microvascular blood volume (MBV) measured using contrast-enhanced ultrasound in both the ischemic (left) and control (right) hind limb. Ischemic to control limb (I/C) ratios were calculated. Hyperinsulinemic euglycemia clamps were performed to determine microvascular responses to insulin. Hind limb ischemic surgery decreased total limb blood flow by ∼70% immediately, from a pre-surgical I/C ratio of 1.10 ± 0.07 to 0.34 ± 0.06. The I/C ratios then progressively increased to 0.45 ± 0.08, 0.54 ± 0.06, 0.67 ± 0.11, and 0.74± 0.11 on postsurgical day 3, 7, 14 and 21 respectively. Similarly, ischemic surgery decreased MBV promptly from a pre-surgical I/C ratio of 1.01 ± 0.04 to 0.39 ± 0.06. MBV I/C ratios completely recovered on day 3 (1.11 ± 0.09) and remained stable afterwards. Insulin induced similar increases in muscle MBV in both legs before surgery (I/C ratio 1.14 ± 0.16) but the increase was much less in ischemic leg on day 3 (I/C ratio 0.63 ± 0.15). Microvascular insulin responses fully recovered on day 7 (I/C ratio 0.97± 0.25). We conclude that hind limb ischemia is associated with decreased total blood flow, muscle microvascular perfusion as well as microvascular responses to insulin. While the recovery in muscle microvascular perfusion precedes that of total limb blood flow, recovery in muscle microvascular response to insulin is delayed. These changes may contribute to muscle injury in patients with diabetes and the muscle microvasculature is potentially a therapeutic target for PAD.

Disclosure

N. Wang: None. Z. Liu: None.

Funding

American Diabetes Association (1-17-ICTS-059 to Z.L.); National Institutes of Health (R01DK102359)
1938-P: GLP-1 Receptor Agonist Ameliorates Intramyocellular Lipid Deposition without Weight Loss by Activating AMPK
Authors: XU FEN , CAO HUANYI , CHEN ZONGLAN , GU HUIMIN , GUO WANRONG , LIN BEISI , WENG JIANPING
Published: June 2019

Objective: Ectopic deposition of lipids is closely related with type 2 diabetes (T2D). Whether and how GLP-1 receptor agonists (GLP-1 RAs) ameliorate lipid deposition in skeletal muscle remain unknown. Here, we investigate the effect of GLP-1 RA exenatide on intramyocellular lipid deposition of skeletal muscle in T2D models and whether this process depends on weight loss.

Methods: ob/ob mice and diet-induced obese (DIO) mice were treated with exenatide, leptin or saline control i.p. for four weeks. Systemic phenotypic evaluations were carried out during and after the intervention. An in vitro model used palmitate-treated myoblast C2C12 cells. The expression of key enzymes involved in lipid metabolism was assessed in skeletal muscle of ob/ob mice and DIO mice.

Results: In ob/ob mice, body weight and fat mass were not improved by four-week exenatide treatment. However, intramyocellular lipid deposition and lipid profiles were still modestly ameliorated by exenatide. In DIO mice, body weight, lipid profiles and intramyocellular lipid were all remarkably alleviated by exenatide but not by leptin. In skeletal muscle of these two models, activated AMPK signaling pathway, stimulated lipid oxidative enzymes and improved insulin signaling pathway were observed by exenatide treatment. In vitro, exendin-4 activated AMPK signaling pathway and promoted lipid metabolism to improve lipid accumulation in palmitate-treated myoblast C2C12 cells, and inhibiting AMPK abolished this effect.

Conclusion: Exenatide ameliorates intramyocellular lipid deposition before the weight loss effect appears in ob/ob mice. While both body weight and intramyocellular lipid are alleviated remarkably at the same time by exenatide in DIO mice. Thus, the effect of exenatide on ameliorating intramyocellular lipid deposition could be independent on weight loss by activating AMPK signaling pathway.

Disclosure

F. Xu: None. H. Cao: None. Z. Chen: None. H. Gu: None. W. Guo: None. B. Lin: None. J. Weng: None.
1939-P: Intermuscular Adipose Tissue Has a Metabolically Adverse Secretome Compared with Visceral and Subcutaneous Depots
Authors: KAHN DARCY E. , MACIAS EMILY , ZARINI SIMONA , HARRISON KATHLEEN A. , CREE-GREEN MELANIE , BERGMAN BRYAN C.
Published: June 2019

Adipose tissue is a dynamic secretory organ that has differing effects on metabolic disease depending upon location and composition. Resting beneath the fascia, and bordering muscle fibers, intermuscular adipose tissue (IMAT) secretes proteins and lipid signaling molecules that are uniquely positioned to directly impact insulin sensitivity and inflammation in skeletal muscle. Individuals with Obesity and type 2 diabetes have increased IMAT volume, and while IMAT is inversely correlated with muscle strength, function, and insulin sensitivity, the mechanisms by which it exerts these effects are unknown. We quantified the secretome of IMAT, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) to determine if there are differences between depots in the secretion of cytokines, eicosanoids, FFAs and proteins that influence metabolic function. SAT and VAT biopsies from bariatric surgery patients and IMAT from the vastus lateralis biopsies of individuals with Obesity were cultured for 48 hours in DMEM, and the conditioned media was analyzed using nanoflow HPLC-MS, multiplex ELISAs and LC/MS/MS for proteins, cytokines and eicosanoids/FFA, respectively. IMAT secretion of various extracellular matrix proteins was significantly different than VAT and SAT. Pro-inflammatory cytokine secretion of IFNγ, TNFα, IL-8 and IL-13 from IMAT was higher than VAT and significantly higher than SAT (p < 0.05). IMAT secretes significantly more pro-inflammatory eicosanoids TXB2 and PGE2 than VAT (p = 0.02, 0.05) and SAT (p = 0.01, 0.04). IMAT and VAT have significantly greater basal lipolysis assessed by FFA release rates compared to SAT (p = 0.01, 0.04). These data begin to characterize the disparate secretory properties of SAT, VAT and IMAT that may impact tissue function, and suggest that the metabolically adverse secretome of IMAT, with such proximity to skeletal muscle may play an important functional role in the pathogenesis of insulin resistance and type 2 diabetes.

Disclosure

D.E. Kahn: None. E. Macias: None. S. Zarini: None. K.A. Harrison: None. M. Cree-Green: None. B.C. Bergman: Advisory Panel; Spouse/Partner; AstraZeneca, Merck & Co., Inc., Novo Nordisk Inc.

Funding

National Institutes of Health (R01DK118149, RR-00036); Colorado Nutrition Obesity Research Center (P30DK048520)
194-LB: Effectiveness of Following Mediterranean Diet (MedDiet) Recommendations in the Real World in the Incidence of Gestational Diabetes Mellitus (GDM) and Adverse Maternal-Fetal Outcomes: A Prospective, Universal Interventional Study
Authors: DURAN ALEJANDRA , DE LA TORRE NURIA GARCIA , ASSAF-BALUT CARLA , DEL VALLE LAURA , INES JIMENEZ , VALERIO DEOGRACIA JOHANNA , BORDIU ELENA , FUENTES MANUEL , BARABASH ANA , CUESTA MARTIN , RUBIO MIGUEL A. , CALLE ALFONSO L.
Published: June 2019

Background: We previously reported that a MedDiet, supplemented with extra-virgin olive oil (EVOO) and pistachios, reduces GDM incidence (WHO criteria) and several adverse outcomes. To assess effects in the in the real world we evaluated the adoption of a MedDiet starting at the 1st gestational visit on the rate of GDM (compared with the control group/CG and intervention group/IG from the previous trial). We also compared the rate of adverse perinatal outcomes between women with and without GDM.

Research Design and Methods: This is a prospective, clinic-based, interventional study with a single group. All normoglycemic women attending their 1st gestational visit <12 gestational weeks (GW) between November 2016-2017 were invited to participate; 1066 signed an informed consent. Women received lifestyle guidance with emphasis on consuming EVOO and nuts daily. 932 women were analyzed. Binary regression analyses were performed to assess the risk of pregnancy-induced hypertension, preeclampsia, gestational weight gain (GWG), C-section, perineal trauma, preterm delivery, small/large-gestational-age new-borns and admissions in neonatal ICU and observation.

Results: GDM rate was of 13.9%; this was significantly lower than the CG: RR 0.81 (0.73-9.28),p<0.001 and no different to the IG:RR 0.96 (0.85-1.07),p=0.468. GWG (kg) was lower in GDM women (10.88±6.46 vs. 12.30±5.42; p=0.013). Excessive weight gain was also lower (RR 0.91 (0.86-0.96)) without a significant increase of insufficient weight gain. We found no differences in any perinatal adverse outcomes.

Conclusion: This study translates evidence to clinical practice, providing a universal and easy-to-apply approach to reduce GDM. An early nutritional intervention before GDM diagnosis ameliorates differences in maternofoetal adverse outcomes between GDM and no-GDM women.

Disclosure

A. Duran: None. N. Garcia de la Torre: None. C. Assaf-Balut: None. L. Del Valle: None. J. Ines: None. J. Valerio Deogracia: None. E. Bordiu: None. M. Fuentes: None. A. Barabash: None. M. Cuesta: None. M.A. Rubio: None. A.L. Calle: None.

Funding

Instituto de Salud Carlos III of Spain; Fondo Europeo de Desarrollo Regional; Sociedad de Endocrinolog?a Nutrici?n y Diabetes de la Comunidad de Madrid (IPI/2017/NR2)
1958-P: Role of Leptin in Blood-Brain Barrier Dysfunction
Authors: SALAMEH THERESE S. , MORTELL WILLIAM , BANKS WILLIAM A.
Published: June 2019

All forms of diabetes mellitus are characterized by chronic hyperglycemia resulting in the development of a number of microvascular and macrovascular pathologies. Diabetes is also associated with changes in brain microvasculature leading to dysfunction and disruption of the blood-brain barrier (BBB). These changes are correlated with a decline in cognitive function. The BBB is a regulatory interface between brain and blood, preventing the unrestricted leakage of plasma proteins into the central nervous system (CNS) and performing nutritive, homeostatic, and communication roles. Studies have shown that in a streptozotocin-induced mouse model of type 1 diabetes, where insulin and leptin levels are low, BBB dysfunction occurs in five brain regions: frontal cortex, occipital cortex, parietal cortex, midbrain, and thalamus. In contrast, in a diet induced obese (DIO) model of type 2 diabetes, where insulin and leptin levels are high, BBB dysfunction did not occur in those five regions but did occur in the hippocampus and hypothalamus. In both models, all mice were hyperglycemic, indicating that this is not the only mechanism by which BBB dysfunction occurs. To further investigate the role of the hormones leptin and insulin in BBB dysfunction, we utilized the BTBR.Cg-Lepob/WiscJ ob/ob mice, a transgenic model of type 2 diabetes where insulin is high and no leptin is present. Using radioactively labeled ligands, we have demonstrated that loss of leptin leads to BBB dysfunction in all brain regions as early as four weeks of age. Importantly, these mice are not born with this dysfunction as studies in two-day old pups demonstrate an intact BBB. Replenishment of leptin to these BTBR.Cg-Lepob/WiscJ ob/ob mice from birth was able to attenuate BBB dysfunction observed at four-weeks of age. These studies indicate that leptin is a key component in maintaining BBB integrity in diabetes.

Disclosure

T.S. Salameh: None. W. Mortell: None. W.A. Banks: None.

Funding

National Institute of Neurological Disorders and Stroke (1R21NS093368-01A1)
1959-P: Upregulation of PYY, GLP-1, and NTS by Intermittent Hypoxia in Enteroendocrine Cells
Authors: SHOBATAKE RYOGO , OTA HIROYO , ITAYA-HIRONAKA ASAKO , YAMAUCHI AKIYO , MAKINO MAI , SAKURAMOTO-TSUCHIDA SUMIYO , UCHIYAMA TOMOKO , TAKAHASHI NOBUYUKI , UENO SATOSHI , SUGIE KAZUMA , TAKASAWA SHIN
Published: June 2019

The patients with sleep apnea syndrome (SAS) are exposed to intermittent hypoxia (IH) during sleep. Although accumulating evidence indicates a strong relationship between SAS and obesity, we previously demonstrated that IH up-regulates the mRNA levels of anorexigenic peptides POMC and CART via GATA transcription factors in human neuronal cells (Int. J. Biochem. Cell Biol. 95, 100, 2018). Appetite is regulated not only by the central nervous system but also by gastrointestinal peptides. Here, we investigated the effect of IH on the appetite-inhibiting gut hormone expression using in vitro IH system. Human and mouse enteroendocrine cells, Caco-2 and STC-1, were exposed to IH [64 cycles of 5 min hypoxia (1% O2) and 10 min normoxia (21% O2)] or normoxia for 24 hours. Real-time RT-PCR revealed that IH significantly increased the mRNA levels of PYY, GLP-1, and neurotensin (NTS) in both Caco-2 and STC-1. ELISA showed that the concentrations of PYY, GLP-1, and NTS in the culture medium were significantly increased by IH. To determine whether the IH-induced increases in PYY, GLP-1, and NTS in enteroendocrine cells were caused by transcriptional activation, reporter plasmids for PYY, GCG, which encodes a preprotein, part of which is cleaved into GLP-1, and NTS were transfected into Caco-2, and the luciferase activity was measured after the IH treatment. The promoter activities of PYY, GCG and NTS were not increased by IH. We then searched targeted miRNA and found that PYY, GLP-1 and NTS mRNAs have potential target sequences for miR-96, -527, and -2116. We measured the levels of the miRNAs and found that the levels of the miRNAs were not decreased by IH. Furthermore, the mRNA levels of PYY, GLP-1, and NTS were significantly up-regulated even in normoxia by trichostatin A and were significantly decreased even in IH by 5-azacytidine, suggesting that IH increases PYY, GLP-1, and NTS mRNAs via alterations in the chromatin structure in enteroendocrine cells. IH might have an anorexigenic influence on the enteric nervous system.

Disclosure

R. Shobatake: None. H. Ota: None. A. Itaya-Hironaka: None. A. Yamauchi: None. M. Makino: None. S. Sakuramoto-Tsuchida: None. T. Uchiyama: None. N. Takahashi: None. S. Ueno: None. K. Sugie: None. S. Takasawa: None.
196-OR: Pharmacological Modulation of Prostaglandin E2 Receptor Activity Enhances ß-Cell Mass in a Mouse Model of Type 2 Diabetes and Human Islets
Authors: ANDREI SPENCER R. , DUNN JENNIFER C. , CHRISTENSEN ASHLEY A. , RICCIARDI VALERIE F. , PACE WILLIAM A. , BREYER RICHARD M. , GANNON MAUREEN
Published: June 2019

Type 2 diabetes (T2D) is characterized by chronic hyperglycemia and low-grade inflammation. Failure to expand β-cell mass in response to insulin resistance can lead to T2D. The hyperglycemia and chronic inflammation observed in T2D is associated with enhanced levels of prostaglandin E2 (PGE2) synthesis in pancreatic islets. Downstream effects of PGE2 signaling are carried out by four E-Prostanoid (EP) G-protein coupled receptors, EP1-4. Recent investigations by our lab demonstrated that EP3 and EP4 play opposing roles in pancreatic islets whereby EP3 activation inhibits β-cell proliferation and survival while EP4 activation stimulates β-cell mass expansion and reduces cytokine-induced cell death ex vivo. Preliminary data suggests that db/db mice (a model of T2D) treated with the EP3 antagonist, DG-041, exhibit enhanced levels of β-cell proliferation when compared to their vehicle-treated counterparts (3.04 ± 0.6% Ki67+/Ins+ β-cells and 1.67 ± 0.2%, respectively). Although differences in β-cell death between the vehicle- (0.09 ± 0.1% TUNEL+ β-cells) and DG-041-treated cohorts (0.23 ± 0.1%) did not reach statistical significance, treatment with the EP3 antagonist ultimately culminated in improved β-cell mass in db/db mice (1.57 ± 0.2 mg) compared to vehicle-treated controls (0.94 ± 0.2 mg). Additionally, preliminary results suggest that the EP3 antagonist-induced increase in β-cell proliferation in nondiabetic human cadaver donors occurs, in part, through PLCγ-1 whereby pretreatment of human islets with U-73122 (PLCγ-1 inhibitor) prior to DG-041 addition resulted in decreased β-cell proliferation (1.67 ± 0.2 fold of vehicle-treated control) when compared to the EP3 antagonist alone (2.30 ± 0.3 fold). Taken together, these results provide valuable foundational insight into the potential role of EP3 in the modulation of β-cell mass expansion.

Disclosure

S.R. Andrei: None. J.C. Dunn: None. A.A. Christensen: None. V.F. Ricciardi: None. W.A. Pace: None. R.M. Breyer: None. M. Gannon: None.
1963-P: Undercarboxylated Osteocalcin Is Correlated with Insulin Secretion in Japanese Individuals with Diabetes
Authors: FUNAKOSHI SHOGO , OHMI SATOKO , AMANO ERI , TERADA YOSHIO , FUJIMOTO SHIMPEI
Published: June 2019

Background and Aims: Undercarboxylated osteocalcin (ucOC) is a secreted protein produced by osteoblasts. UcOC can regulate insulin secretion and insulin sensitivity in rodents. Pharmacological administration of ucOC enhances insulin secretion which could be mediated by GLP-1 in mice. However, pathophysiological roles of ucOC in glucose intolerance in human remain unknown. In this study, we aimed to investigate the association between ucOC and glucose metabolism in individuals with varying degrees of glucose tolerance.

Materials and Methods: The 75-g oral glucose tolerance test was carried out in 75 Japanese individuals not taking diabetes medications [age: 65±11 (mean±SD); male/female: 34/41; BMI: 24.9±3.8]. Individuals were classified as normal (NGT), impaired glucose tolerance (IGT), and diabetes (DM) groups (each group: n=25). The insulinogenic index (IGI) as an index of insulin secretion, and QUICKI and the Matsuda Index (MI) as indices of insulin sensitivity were calculated. Fasting serum levels of ucOC and leptin were assayed by ECLIA and by ELISA, respectively. Normally-distributed loge-transformed (ln-)values were used for regression analysis in some cases.

Results: Although fasting and 2h after glucose loading plasma glucose, HbA1c, IGI, QUICKI and MI were significantly different among the 3 groups, age, sex, BMI, and ucOC were not different. In simple regression analysis in each group, ln-ucOC was not correlated with QUICKI and ln-MI in all 3 groups. Interestingly, ln-ucOC was correlated with ln-IGI (r=0.422, P=0.0345) and HbA1c (r=-0.574, P=0.0022) only in DM. In multiple regression analysis in DM, ln-IGI was independently predicted by BMI (β=0.598) and ln-ucOC (β=0.641) (R2=0.488, P=0.0006) and by ln-leptin (β=0.624) and ln-ucOC (β=0.448) (R2=0.568, P<0.0001).

Conclusion: UcOC was correlated with insulin secretion independently of adiposity in Japanese individuals with diabetes.

Disclosure

S. Funakoshi: None. S. Ohmi: None. E. Amano: None. Y. Terada: None. S. Fujimoto: None.
1968-P: Improved Glucose Tolerance via Somatostatin Receptor Antagonism Is an Effect Mediated by the Intestine
Authors: JEPSEN SARA L. , HOLST JENS J.
Published: June 2019

Antagonising the peptide hormone somatostatin (SS) is a novel promising approach to improve glycaemic control. SS inhibits secretion of glucagon-like peptide-1 (GLP-1), via binding to five SS receptors (SSTr1-5). Subtype specific SSTr antagonists can improve glycaemic control after an oral glucose tolerance test (OGTT) in mice, but the mechanism is still unclear. We hypothesized that the effect on glucose tolerance by antagonising SS may be intestinally derived involving GLP-1 rather than a direct effect on the pancreas. We investigated whether addition of a DPP-4 inhibitor would enhance the effect on glucose tolerance by subcutaneous (s.c.) injection of two SSTr antagonists specific for SSTr2 (SSTr2a) and SSTr5 (SSTr5a) in vivo in mice. Next, we used the same antagonists together with s.c. glucose to avoid release of endogenous incretins to estimate the intestinal contribution. Using SSTr5 knockout (KO) mice, which already have improved glycaemic control, we did an OGTT in combination with a GLP-1 receptor antagonist (exendin9-39) to see if the effect is mediated by the GLP-1 receptor. Both SSTr2a and SSTr5a lowered blood glucose levels (AUC) compared to the control group (PBS 34.06 (mmol/l)×min, SSTr2a 23,35 (mmol/l)×min, SSTr5a 26.59 (mmol/l)×min). The DPP-4 inhibitor in combination with SSTr2a markedly lowered glucose levels (AUC after SSTr2a+DPP-4 inhib: 9.8 (mmol/l)×min) whereas the combination with SSTr5a resulted in a minor additive effect (SSTr5a+DPP-4 inhib: 19.7 (mmol/l)×min). Interestingly the effect of the SSTr antagonists was completely lost when glucose was given s.c. and no lowering effect on glucose was observed. In SSTr5 KO mice, glucose tolerance was improved compared to wild type (WT) littermates (WT 30.6 (mmol/l)×min), SSTr5 KO 17.9 (mmol/l)×min), which was markedly impaired when given Exendin9-39. These studies strongly suggest that the effects of antagonising SS are mediated by a GLP-1 based mechanism derived from the intestine.

Disclosure

S.L. Jepsen: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S.
197-LB: Factors Associated with Screening for Diabetes in Low-Income Women after a Pregnancy with Gestational Diabetes
Authors: HERRICK CYNTHIA J. , YAN YAN , TROLARD ANNE , COOPER BENJAMIN P. , KELLER MATTHEW , OLSEN MARGARET A.
Published: June 2019

Background: Gestational diabetes (GDM) increases risk for type 2 diabetes seven fold. Women with a history of GDM should be screened for diabetes at 4-12 weeks postpartum and every 1-3 years thereafter. We aimed to characterize factors associated with diabetes screening by 12 weeks and 1 year postpartum in a cohort of low-income women with GDM.

Methods: A retrospective cohort of 1078 women with GDM who delivered from 2010-2015 was generated by linking electronic health record data from 21 Missouri Federally Qualified Health Centers (FQHCs) with Medicaid administrative claims. Screening rates for diabetes were calculated within 12 weeks and one year of delivery. Two multivariable logistic regression models were constructed to determine associations with recommended screening at these time points. Models were adjusted for age, race/ethnicity, comorbidities, prenatal care, previous birth, and distance from home to health center.

Results: Median age was 28 years and 64% of women were racial and ethnic minorities (41% black non-Hispanic). Recommended postpartum screening occurred in 9.7% of women by 12 weeks and 18.9% by 1 year. At 12 weeks and 1 year postpartum, having a prenatal certified diabetes educator visit (12 weeks: aOR 1.9 95% CI 1.1-3.5; 1 year aOR 2.2 95% CI 1.3-3.5) and prior medication for GDM (12 weeks: aOR 2.5 95% CI 1.4-4.3; 1 year aOR 2.7 95% CI 1.7-4.2) were strongly associated with diabetes screening. At 1 year, living in an area with public transportation increased odds of screening two-fold (aOR 2.0 95% CI 1.1-3.8) and each additional encounter with the health system after delivery increased odds of screening by 16% (95% aOR 11-21%).

Discussion: Multiple factors are associated with postpartum screening for diabetes in populations with limited resources. Future interventions to increase screening should focus on enhancing access to prenatal certified diabetes education and addressing barriers related to transportation and health system access.

Disclosure

C.J. Herrick: Stock/Shareholder; Spouse/Partner; Cardinal Health. Y. Yan: None. A. Trolard: None. B.P. Cooper: None. M. Keller: None. M.A. Olsen: Consultant; Self; Pfizer Inc. Research Support; Self; Merck & Co., Inc., Pfizer Inc., Sanofi Pasteur.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (1P30DK092950, UL1TR000448, KL2TR000450); National Center for Advancing Translational Science (KL2TR002346, UL1TR002345); Agency for Healthcare Research and Quality (R24HS19455); National Cancer Institute (KM1CA156708)
1973-P: Deficiency of Protein Deacetylase Sirt3 Enhances Acetylation of Histone H3 and H4 as to Affect Glucose Metabolism through Regulation of Dipeptidyl Peptidase-4 in Mice
Authors: UTO ASUKA , MIYASHITA KAZUTOSHI
Published: June 2019

Background: Sirt3 is a NAD-dependent deacetylase that regulates lipid metabolism in mice and is related to longevity through modification of epigenome. Sirt3-deficient knockout (KO) mice fed a high-fat diet have been shown to develop obesity and metabolic syndrome-like phenotype. However, the precise mechanism by which they cause glucose intolerance has not been known. To reveal the regulatory mechanism of glucose metabolism through Sirt3, the metabolic parameters in the Sirt3-KO mice were examined.

Objective and Methods: The histone acetylation levels in various organs of the Sirt3-KO mice were examined by immunostaining of acetylated histone H3 (H3Ac) and H4 (H4Ac). Blood glucose levels in the Sirt3-KO mice after glucose loading were examined, associated with blood glucagon-like peptide-1 (GLP-1) levels and dipeptidyl peptidase-4 (DPP-4) activity. Gene expressions which were associated with the expressions and functions of GLP-1 and DPP-4 were quantified by qPCR.

Results: The Sirt3-KO mice were subjected to an oral glucose tolerance test (OGTT), together with an intraperitoneal glucose tolerance test (ipGTT). OGTT revealed an increase in the blood glucose levels in the KO mice, although ipGTT did not show the increase after the glucose loading. The blood GLP-1 and insulin levels decreased, and the DPP-4 activity increased significantly in the KO mice. qPCR analysis revealed a predominance of Sirt3 expression in the intestinal tract in the wild type mice. The immunostaining of H3Ac and H4Ac showed enhanced intensity in the small intestine and colon, and in the vascular endothelial cells in the KO mice.

Conclusion: These results suggest that Sirt3 deficiency impairs the incretin effect by a suppression of the blood GLP-1 levels and causes glucose intolerance. Enhanced acetylation of histone H3 and H4 in the KO mice might relate to the increase in the DPP-4 activity, which lead to the decrease in the GLP-1 levels.

Disclosure

A. Uto: None. K. Miyashita: Research Support; Self; Johnson & Johnson, Merck & Co., Inc., Novo Nordisk Inc.
1975-P: Increased Pancreatic a Cell Ca2+ Oscillations Explain Hyperglucagonemia in High-Fat Diet-Fed Mice
Authors: KELLARD JOELY , BRIANT LINFORD , KNUDSEN JAKOB G. , RORSMAN PATRIK
Published: June 2019

Glucagon secretion from pancreatic α cells is elevated in obesity, exacerbating hyperglycaemia and contributing to the development of diabetes. α cells exhibit intracellular calcium (Ca2+i) oscillations, which drive glucagon secretion. To understand these oscillations and their contribution (if any) to the diabetic phenotype, we developed a mouse model for studying α cell Ca2+i, and used this to investigate α cell Ca2+i dynamics in mice exposed to a high fat diet (HFD).

Mice expressing GCaMP3 specifically in α-cells (GcgCre x GCaMP3 reporter mouse) were fed a control (10% fat; CTL) or high fat diet (60%; HFD) for 12 weeks. Mice then underwent a glucose tolerance test (GTT). Ca2+i imaging and glucagon secretion experiments were carried out on isolated (ex vivo) islets.

HFD mice had impaired glucose tolerance compared to CTL mice (p<0.0001, n=25 mice). Plasma glucagon was suppressed by high glucose in CTL (p=0.01), but not HFD mice (p=0.65; n=10-20 mice). In islets from both CTL and HFD mice, Ca2+i oscillation frequency was suppressed by high glucose (p<0.0001 n=200-250 cells, 6 islets, 3 mice). However, oscillation frequency was higher in HFD mice vs. CTL (p<0.0001; n= 203-252 cells, 6-9 islets, 3 mice). Oscillation amplitude was not altered by glucose in CTL or HFD mice (p=0.076 and 0.87 respectively, 31-67 cells, 6-7 islets, 3 mice). Pharmacological approaches suggested that the increase in oscillation frequency was not due to altered α cell fat metabolism (p=0.5 38-68 cells, 4 islets, 3 mice). Insulin secretion from ex vivo islets was elevated in HFD vs. CTL mice, although this did not reach significance (p=0.084; N=6 mice).

These preliminary data suggest that hyperglucagonemia in HFD mice may have origins intrinsic to the islet. This was not due to reduced paracrine regulation by insulin, as insulin secretion was elevated in HFD mice. Future experiments will aim to fully power this study and understand whether α cell intrinsic mechanisms contribute to the hyperglucagonemic phenotype.

Disclosure

J. Kellard: None. L. Briant: None. J.G. Knudsen: None. P. Rorsman: None.

Funding

UK Wellcome Trust
198-LB: Maternal Plasma AGEs and Preeclampsia in Women with Type 1 Diabetes
Authors: KARANCHI HARSHA , KELLY CLARE B. , HAMMAD SAMAR M. , KLEIN RICHARD L. , LOPES-VIRELLA MARIA F. , LEYVA MISTI J. , YU JEREMY , JENKINS ALICIA J. , NANKERVIS ALISON J. , HANSSEN KRISTIAN F. , ASTON CHRISTOPHER E. , HOWELL SCOTT , BEISSWENGER PAUL J. , LYONS TIMOTHY
Published: June 2019

Preeclampsia (PE) occurs four times more frequently in pregnant women with type 1 diabetes (T1D) than in nondiabetic women. We hypothesized that elevated plasma advanced glycoxidation products (AGEs) predict PE in T1D women. In a prospective T1D pregnancy cohort (study visits at 12, 22, 32 weeks' gestation), we used liquid chromatography/mass spectrometry, with internal stable heavy isotope substituted standards, to determine plasma levels of nine AGE and oxidation products (carboxymethyl-lysine [CML], carboxyethyl-lysine [CEL], methylglyoxal-hydroimidazolone [MGHI], 3-deoxyglucosone hydroimidazolones [3DGH], methionine sulfoxide [MetSO], glyoxal hydroimidazolone [GHI], 3-nitrotyrosine [3NT], dityrosine [DT], 2-aminoadipic acid [2AAA]) in 23 women with T1DM who developed PE vs. 24 who did not, and in 19 nondiabetic normotensive pregnant women. These products have been associated with CVD and renal failure in non-pregnant cohorts. All women were free of microalbuminuria and hypertension at enrolment, and all visits preceded clinical PE onset. GFR was estimated (Chronic Kidney Disease Epidemiology Collaboration equation).

Results: Plasma CML, CEL, MGHI, 3DGH, MetSO, GHI, and 2AAA did not differ between the three groups at any study visit, and thus did not predict preeclampsia in T1D. In T1D women who later developed PE, eGFR was inversely associated at V3 with CML (p=0.008), CEL (p=0.03), MGH1 (p=0.03), 3DGH (p=0.03), GHI (p<0.001), and 2AAA (p<0.05); and at V2 with CEL (p=0.04), MGHI (p=0.02), and GHI (p=0.02). No such associations were observed in normotensive T1D or in nondiabetic pregnant women. Plasma levels of 3NT and DT were undetectable in all participants.

Conclusions: Plasma AGEs did not predict PE in well-controlled, previously healthy T1D women, and levels did not differ from healthy nondiabetic controls. Uniquely, in T1D women who developed PE, plasma AGEs were associated with renal function, consistent with the notion that subclinical alterations in renal function precede PE.

Disclosure

H. Karanchi: None. C.B. Kelly: None. S.M. Hammad: None. R.L. Klein: None. M.F. Lopes-Virella: None. M.J. Leyva: None. J. Yu: None. A.J. Jenkins: Advisory Panel; Self; Abbott, Australian Diabetes Society, Medtronic. Research Support; Self; Abbott, GlySens Incorporated, Medtronic, Mylan. Speaker’s Bureau; Self; Eli Lilly and Company, Novo Nordisk Inc. A.J. Nankervis: None. K.F. Hanssen: None. C.E. Aston: None. S. Howell: Employee; Self; PreventAGE Health Care, LLC. P.J. Beisswenger: Other Relationship; Self; PreventAGE Health Care, LLC. T. Lyons: None.
1982-P: Glucagon-Like Peptide-2 Inhibits Postprandial Gallbladder Emptying in Healthy Male Individuals—A Randomized, Double-Blinded, Placebo-Controlled Study
Authors: HANSEN NINA L. , NEXØE-LARSEN CHRISTINA CHARLOTTE , BRØNDEN ANDREAS , CHRISTENSEN ALEXANDER S. , SONNE DAVID P. , HARTMANN BOLETTE , VILSBØLL TINA , HOLST JENS J. , KNOP FILIP K.
Published: June 2019

A recent study in mice has demonstrated that the gut-derived hormone glucagon-like peptide-2 (GLP-2) may be involved in the regulation of gallbladder motility and induces gallbladder refilling. This study evaluated the effect of exogenous GLP-2 on postprandial gallbladder motility in humans. On three experimental days, 15 young healthy males ([mean±SEM] age 24.3±1.9 years, BMI 22.5±0.9 kg×m-2, HbA1c 4.8±0.1% (29.3±1.5 mmol/mol)) were subjected to a 3.5-hour 300 kcal mixed liquid meal-test. Continuous 4-hour intravenous infusions of placebo (saline), low-dose GLP-2 (1 pmol×kg-1×min-1) or high-dose GLP-2 (10 pmol×kg-1×min-1) were initiated 30 min before meal ingestion. Gallbladder volume was determined by ultrasonography, and gallbladder ejection fraction was calculated. Postprandial maximum gallbladder ejection fraction during saline infusion (76.3±2.8%) was significantly reduced by low-dose GLP-2 (65.5±3.5%, P=0.026) and completely abolished during high-dose GLP-2 infusion (4.0±3.7%, P<0.0001) (Figure). Postprandial peak plasma glucose was lower during high-dose GLP-2 infusion (6.4±0.2 mmol/l) compared to low-dose GLP-2 (6.9±0.2mmol/l, P=0.0004) and placebo infusion (7.2±0.2 mmol/l, P=0.008).

In conclusion, exogenous GLP-2 dose-dependently inhibits postprandial gallbladder emptying in healthy male subjects.

Disclosure

N.L. Hansen: None. C.C. Nexøe-Larsen: None. A. Brønden: Other Relationship; Self; AstraZeneca. A.S. Christensen: None. D.P. Sonne: None. B. Hartmann: None. T. Vilsbøll: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. F.K. Knop: Advisory Panel; Self; AstraZeneca, MedImmune, Merck Sharp & Dohme Corp., Mundipharma, Novo Nordisk A/S, Sanofi. Consultant; Self; Amgen Inc., Carmot Therapeutics, Novo Nordisk A/S. Research Support; Self; AstraZeneca, Novo Nordisk A/S. Speaker's Bureau; Self; AstraZeneca, MedImmune, Merck Sharp & Dohme Corp., Mundipharma, Norgine, Novo Nordisk A/S.
1983-P: WNT Pathway and Bone Fragility in Postmenopausal Women with Type 2 Diabetes
Authors: PICCOLI ALESSANDRA , CANNATA FRANCESCA , RUSSO FABRIZIO , GRETO VALENTINA L. , ISGRÒ CAMILLA , LEANZA GIULIA , STROLLO ROCKY , MASSARONI CARLO , PEDONE CLAUDIO , SILVESTRI SERGIO , VADALÀ GIANLUCA , DENARO VINCENZO , BISOGNO TIZIANA , PAPALIA ROCCO , POZZILLI PAOLO , MACCARRONE MAURO , NAPOLI NICOLA
Published: June 2019

Fragility fractures are major complications in type 2 diabetes (T2D), but mechanisms underlying bone fragility are still poorly clarified. Bone mineral density (BMD) underestimates T2D fracture incidence, since a normal or even higher BMD is associated with a greater fracture risk than healthy population. We hypothesized that bone fragility in T2D results from poor bone microarchitecture and bone quality caused by WNT signaling impairment and lower bone formation. We aimed to evaluate the association between bone gene expression of WNT pathway and features of bone microarchitecture and strength. We enrolled T2D (n=13) and nondiabetic (controls, n=75) postmenopausal women undergoing standard hip arthroplasty. Serum and proximal femur samples from recruited subjects were collected at the moment of surgical procedure. Gene expression of sclerostin (SOST), WNT5a, WNT10b, SFRP5, GSK3β, osteocalcin and RUNX2 was analyzed by real-time PCR. Total-body, lumbar and femoral BMD were assessed by bone densitometry. A trabecular core from bone samples was analyzed by Micro X-ray computed tomography and by compression tests. Age (75.23 ± 8.47 vs. 73.24 ± 5.77) and BMI (29.92 ± 5.38 vs. 27.68 ± 5.62 Kg/m2) did not differ between T2D and controls respectively. Glycated hemoglobin was 6.48 ± 1.7 mmol/mol. We found that T2D subjects had no differences in BMD and in bone microarchitecture parameters compared to controls. Neither bone turnover nor WNT serum markers differed among groups. SOST gene expression was increased (p=0.003) whereas RUNX2 expression was decreased in T2D vs. controls (p=0.017), independently by BMI and age. Osteocalcin and other WNT related genes expression did not differ among groups. Compression tests did not show impairment in bone strength in T2D vs. controls.

In conclusion, although a good glycemic control and no alterations in bone density, microarchitecture and strength, we found an increase in SOST and a decrease in RUNX2 gene expression, implying a lower bone formation in T2D.

Disclosure

A. Piccoli: None. F. Cannata: None. F. Russo: None. V.L. Greto: None. C. Isgrò: None. G. Leanza: None. R. Strollo: None. C. Massaroni: None. C. Pedone: None. S. Silvestri: None. G. Vadalà: None. V. Denaro: None. T. Bisogno: None. R. Papalia: None. P. Pozzilli: None. M. Maccarrone: None. N. Napoli: None.

Funding

Campus Bio-Medico University
199-LB: Low Prevalence of Small-for-Gestational-Age in Women with Type 1 Diabetes and Chronic Hypertension
Authors: HELMAN SARIT , JAMES-TODD TAMARRA , BROWN FLORENCE M.
Published: June 2019

Objective: To evaluate delivery outcomes in women with concurrent type 1 diabetes and chronic hypertension (cHTN) treated with anti-hypertensive pharmacotherapy to target blood pressure (BP) 110-129/65-79 mmHg throughout pregnancy per ADA 2008-2016 guidelines.

Research Design and Methods: We abstracted clinical data from the medical records of 752 pregnancies derived from 550 women seeking prenatal care at the Joslin Diabetes Center and Beth Israel Deaconess Medical Center’s Diabetes in Pregnancy Program from 2004-2017. We calculated means and percentages, used t test or ?2 test, and linear regression to compare trimester specific BP values, birth weight and prevalence of small for gestational age (SGA) in pregnancies of women with type 1 diabetes and cHTN to those with type 1 diabetes and no cHTN.

Results: Type 1 diabetes and cHTN occurred in 51 (6.7%) of pregnancies and the mean BP values were 128/76 in the first trimester; 122/72 in the second trimester; 124/76 in the third trimester; 137/82 prior to delivery. BP values were significantly higher in women with type 1 diabetes and cHTN for each trimester compared to women with type 1 diabetes and no cHTN (p<0.001). Women with type 1 diabetes and cHTN were older (33.4 vs. 31.5 years p=0.04), had higher BMI (28.3 vs. 26.6 kg/m2 p=0.03), were more likely to have diabetic nephropathy (10.4% vs. 2%, p<0.001) and use insulin pumps (75.5% vs. 60%, p=0.04). There were no significant differences in gestational age at delivery and birth weight. SGA in both groups was rare, with 0 (0%) in the type 1 diabetes with cHTN group and 5 (0.9%) in the group without cHTN (p=0.54).

Conclusion: SGA is rare in pregnancies complicated by type 1 diabetes and cHTN and did not differ from those without cHTN, even when BP targets of 110-129/65-79 mmHg are used. This may provide reassurance to reestablish these lower BP targets rather than the recently adopted higher targets of 120-160/80-105 mmHg followed by ACOG since 2013 and ADA since 2017.

Disclosure

S. Helman: None. T. James-Todd: None. F.M. Brown: None.
199-OR: Time-Restricted Feeding Ameliorates Metabolic Dysfunction through the Restoration of Circadian Beta-Cell Function and Transcriptional Identity
Authors: BROWN MATTHEW , HER TRACY K. , MATVEYENKO ALEKSEY
Published: June 2019

There are clear associations between circadian disruption (CD), induction of pancreatic β-cell failure and T2DM. However, the underlying mechanisms driving these associations remain unclear. CD is behaviorally characterized by the dysregulation of circadian feeding patterns, which play a key role in the regulation of glucose homeostasis. Therefore, we set out to test the hypothesis that disrupted circadian feeding patterns mediate CD-induced metabolic dysfunction by promoting β-cell failure and reprogramming of the circadian islet transcriptome. To address this, C57B6 mice were assigned into 3 protocols for 12 weeks: 1) LD: exposed to standard light-dark cycle on ad libitum chow; 2) CD: Constant light exposure, to disrupt endogenous circadian rhythms, on ad libitum chow; 3) CD-tRF: Constant light exposure with time-restricted access to chow (tRF) during the first 8h of the circadian “active/feeding” phase. CD led to a loss of circadian rhythmicity in feeding, activity and energy expenditure (p<0.05 vs. LD). These behavioral abnormalities corresponded with loss of circadian regulation of glucose tolerance and insulin response (p<0.05 vs. LD). Moreover, time-dependent RNA-seq of islets revealed that CD significantly altered 98% of genes that were differentially expressed under LD conditions. Restoration of circadian feeding patterns (without altering daily energy intake) in CD-tRF led to reversal of metabolic defects by enhancing circadian glucose tolerance and insulin secretory response (p<0.05 vs. CD). Importantly, CD-tRF normalized circadian expression patterns of 707 genes enriched for KEGG pathways regulating key aspects of β-cell function such as insulin secretion, protein processing in ER, and NF-kB signaling (all FDR<0.05). This study suggests that the deleterious metabolic effects of CD on the β-cell are a consequence of disrupted circadian feeding patterns and imply that tRF may attenuate β-cell failure in T2DM.

Disclosure

M. Brown: None. T.K. Her: None. A. Matveyenko: None.

Funding

National Institutes of Health (R01DK98468)
1996-P: Paternal Gastric Bypass Surgery Confers Protection from Metabolic Syndrome and Hepatic Steatosis in Offspring Mice
Authors: YUCHI YIXING , HAO ZHENG , TAKAGI TOKIYO , BERTHOUD HANS-RUDOLF , PATTI MARY E.
Published: June 2019

Bariatric surgery is increasingly recognized as a potent approach for obesity and T2D. While bariatric surgery in females yields variable effects on offspring, the impact of bariatric surgery in males on metabolism of their offspring is unknown. To determine whether paternal RYGB could induce intergenerational effects, male C57BL/6 mice with Roux-en-Y gastric bypass 5 months earlier (RYGB, n=4) or weight/age-matched controls (CON, n=5) were bred with healthy females of the same strain; 3 pregnancies were achieved by RYGB and 6 by CON males. Birth weight of offspring from RYGB or CON fathers did not differ. Seven offspring (2 litters) of RYGB fathers and 12 (2 litters) of CON fathers survived to weaning. On chow diet, male offspring of RYGB fathers reduced weight gain over time (p<0.05 vs. CON) but there was no significant difference in insulin sensitivity or glucose tolerance at 3 months of age. At 6 months of age, male offspring of RYGB fathers had significantly lower fasting glucose and improved oral glucose tolerance (17% lower AUC, p<0.05). When fed a 45% high-fat diet (HFD) for 15 weeks, RYGB offspring had significantly lower weight gain than control offspring, with lower body weight (37±5.7g vs. 51±1.1g), and reduced fat percentage (36±6.8 vs. 48±1.1%), in turn potentially linked to reduced food intake. Moreover, RYGB offspring had lower fasting glucose, improved insulin sensitivity (intraperitoneal insulin tolerance), and increased respiratory exchange ratio in fed state. In addition, HFD-fed RYGB offspring had dramatic improvement in hepatic steatosis, with 70% of RYGB offspring having no steatosis, as compared with 100% of CON offspring with severe steatosis (p<0.0001).

In conclusion, RYGB surgery in fathers prior to breeding can provide protection against metabolic syndrome and hepatic steatosis in offspring, and suggests that interventions to improve the health of fathers could interrupt intergenerational cycles of obesity and diabetes risk.

Disclosure

Y. Yuchi: None. Z. Hao: None. T. Takagi: None. H. Berthoud: None. M.E. Patti: Consultant; Self; Eiger BioPharmaceuticals. Research Support; Self; Dexcom, Inc., Janssen Pharmaceuticals, Inc., MedImmune, Xeris Pharmaceuticals, Inc.

Funding

The Medical Foundation; National Institutes of Health (DK047348)
200-OR: Role of Delta Cell Gpr120 in the Regulation of Islet Function and Glucose Control
Authors: CROZE MARINE L. , GRANZIERA SABRINA , VIVOT KEVIN , SZPIGEL ANAIS , GHISLAIN JULIEN , POITOUT VINCENT
Published: June 2019

Gpr120 is a long-chain fatty acid receptor expressed in pancreatic islets, where it inhibits the secretion of somatostatin (SST) by the δ cell. SST is a negative regulator of glucoregulatory hormone secretion. However, the precise role of Gpr120 in the regulation of insulin and glucagon secretion is still unclear, as well as the specific islet cell(s) type(s) involved.

Objective: This study aimed at defining the role of pancreatic δ-cell Gpr120 signaling in the regulation of islet function and glucose homeostasis.

Methods: Insulin and SST secretion was measured in isolated islets from WT, Gpr120 KO and Gpr40 KO mice in 1h static incubation in the presence of 2.8 or 16.7 mM glucose with or without synthetic (Compound A, Cpd A) or endogenous (alpha-linolenic, eicosapentaenoic or docosahexaenoic acid) Gpr120 agonists. Glucagon and SST secretion was measured after 1h static incubation in response to arginine with or without Cpd A. Cpd A was administered orally to WT male mice before an oral Glucose Tolerance Test or an Arginine Test, and blood glucose and insulin or glucagon plasma levels were measured.

Results: In isolated islets from WT mice, activation of Gpr120 with either Cpd A or endogenous agonists dose-dependently inhibited glucose-stimulated SST secretion, and concomitantly increased glucose-stimulated insulin secretion. Cpd A also inhibited SST secretion and potentiated glucagon secretion in response to arginine in low glucose conditions. The effects of Cpd A were unaltered in Gpr40 KO islets but disappeared in Gpr120 KO islets. Oral administration of Cpd A improved glucose tolerance and potentiated both glucose-induced insulin secretion and arginine-induced glucagon secretion.

Conclusion: The results demonstrate that Gpr120 activation in islets inhibits SST secretion, potentiates insulin and glucagon secretion, and improves glycemic control.

Disclosure

M.L. Croze: None. S. Granziera: None. K. Vivot: None. A. Szpigel: None. J. Ghislain: None. V. Poitout: None.

Funding

Société Francophone du Diabète; Montreal Diabetes Research Center; Natural Sciences and Engineering Research Council of Canada