bluuebunny/crossref_metadata_2025 huggingface dataset:
33-OR: Intact Muscle Insulin Signaling in Patients with a Gain-of-Function LRP5 Mutation Despite Decreased Insulin Sensitivity
Authors: SABARATNAM RUGIVAN , LAUTERLEIN JENS-JACOB LINDEGAARD , NIELSEN MORTEN FROST , HOJLUND KURT
Published: June 2019

Type 2 diabetes (T2D) is characterized by insulin resistance in skeletal muscle. GWAS studies have shown a link between T2D and Wnt signalling, and there is evidence that mutations in LRP5, a co-receptor in the canonical Wnt signaling pathway, may alter insulin sensitivity. Here, we investigated whether a gain-of-function (GoF) LRP5 mutation causing high bone mass is accompanied by changes in insulin sensitivity and abnormalities in the insulin signalling pathway in skeletal muscle. Skeletal muscle biopsies were obtained before and after a euglycemic-hyperinsulinemic clamp (3-h, 40 mU/min/m2) from 13 patients with GoF LRP5 mutation (T253I) and 14 age, and weight-matched controls. Protein abundance/phosphorylation of key mediators of insulin signalling to glucose transport and glycogen synthesis, such as Akt, TBC1D4, glycogen synthase kinase 3 (GSK3α and ß) and Erk1/2 were investigated. Insulin sensitivity measured as insulin-stimulated glucose disposal (Rd) was reduced (25%) in GoF LRP5 mutation carriers (p<0.05). However, the insulin-stimulated phosphorylation of Akt at Ser473 and Thr308, TBC1D4 at Thr642 and Erk1/2 was fully intact in skeletal muscle of GoF LRP5 mutation carriers. Moreover, both the basal and the insulin-mediated inhibitory phosphorylation of GSK3 (α and ß) were unaltered in muscle of LRP5 mutation carriers compared with controls. To further investigate the molecular consequences of this GoF LRP5 mutation, we are currently investigating key regulators of Wnt signalling (activity of ß-catenin and CaMKII) and performing RNA-sequencing in muscle.

In conclusion, our data demonstrate that reduced insulin sensitivity in GoF LRP5 mutation carriers is not explained by abnormalities in the classical components of the insulin signalling cascade in skeletal muscle. This suggests that the GOF LRP5 mutation negatively affects insulin sensitivity by other mechanisms possible involving over-activation in Wnt signalling.

Disclosure

R. Sabaratnam: None. J. Lauterlein: None. M.F. Nielsen: None. K. Hojlund: None.
336-OR: An Online Insulin Pump and CGM Curriculum for Trainees: TeKnO T1D
Authors: MARKS BRYNN , WALDMAN GRETCHEN , STAFFORD DIANE E. , GARVEY KATHARINE , NAGLER JOSHUA , WOLFSDORF JOSEPH I.
Published: June 2019

Background: A nationwide needs assessment survey identified suboptimal knowledge of insulin pumps and continuous glucose monitors (CGM) among pediatric endocrinology fellows.

Objectives: We developed and assessed the impact of an online, spaced education curriculum- Technology Knowledge Optimization in type 1 diabetes (TeKnO T1D)- on fellows’ knowledge of these technologies.

Methods: Endocrine fellows nationwide were invited to participate in this ongoing prospective, randomized cross over study. The pretest assessment included 20 multiple choice questions. A commercially available electronic spaced education platform (QStream) was used to deliver the material. The posttest assessment was identical and also included two questions assessing reactions to the curriculum. A linear multivariable regression was used to compare the deltas (pre-post) between the two groups adjusted for fellowship year and other covariates.

Results: Sixty-one fellows completed the pretest assessment. To date, 21 (68%) and 18 (60%) fellows have completed the pump and CGM curricula, respectively. Fellows who received the pump curriculum had a 41% greater mean improvement on the posttest questions focused on insulin pumps as compared to the fellow who completed the CGM curriculum (95% CI, 1.05, 1.88). Fellows who completed the CGM curriculum had a 70% greater mean improvement on the post-test questions focused on CGMs as compared to fellows who completed the pump curriculum (95% CI, 1.22, 1.37). The greatest improvements were seen in the following topics: interpretation of CGM trend arrows, pump management during exercise, managing pump disconnections, and unique features of different CGM systems. 97% of fellows agreed or strongly agreed that they enjoyed TeKnO T1D.

Conclusion: TeKnO T1D is an effective, enjoyable way to improve T1D technology knowledge across a large group of geographically dispersed fellows. This learning modality may also have applications for other healthcare professionals as well as patients and families.

Disclosure

B. Marks: None. G. Waldman: None. D.E. Stafford: None. K. Garvey: None. J. Nagler: None. J.I. Wolfsdorf: Other Relationship; Self; UpToDate, Xeris Pharmaceuticals, Inc.

Funding

Pediatric Endocrine Society; Boston Children's Hospital
338-LB: ACh Esterase Is a Novel Regulator of Insulin Secretion in Human Islets
Authors: TAMAYO ALEJANDRO M. , CAICEDO ALEJANDRO
Published: June 2019

The neurotransmitter acetylcholine (ACh) plays a major role in regulating insulin secretion. While in several species parasympathetic innervation provides cholinergic input to beta cells, it is the glucagon secreting alpha cell the major source of ACh in human islets. It is still unclear, however, what is the contribution of cholinergic signaling to beta cell function in humans. Here we analyzed how ACh impacts human beta cell function and insulin secretion, using a combination of in vitro and in vivo approaches. To determine the effect of endogenous ACh in insulin secretion, we manipulated ACh esterase activity using different inhibitors such as pyridostigmine and galantamine. Inhibition of ACh esterase led to a significant increase in insulin secretion in isolated human islets in perifusion experiments. To assess the effect of endogenous ACh on human beta cell function in vivo, we transplanted human islets into the anterior chamber of immunocompromised Nude mice. ACh esterase activity was inhibited by local administration of the ACh esterase inhibitor pyridostigmine as eye drops. To control that the inhibitor was entering the anterior chamber of the eye and reaching the islets, we measured the effect it had on pupil size. 30 microM pyridostigmine induced approximately a 20-30% reduction in pupil size. Importantly, mice treated with 30 microM pyridostigmine showed decreased glucose excursion curves and slightly increased insulin levels 15 min after glucose injection. These results indicate that endogenously released ACh from human alpha cells increases insulin secretion from beta cells in vitro and in vivo. ACh esterase is potential novel target for the treatment of diabetes in humans.

Disclosure

A.M. Tamayo: None. A. Caicedo: None.

Funding

American Diabetes Association (1-17-ICTS-052 to A.C.)
339-LB: Modulation of Insulin and Glucagon Secretion by Optogenetic Control of Delta-Cell Electrical Activity in Pancreatic Islets
Authors: DOU HAIQIANG , MIRANDA CAROLINE A. , ZHANG QUAN , RORSMAN PATRIK , TOLö JOHAN
Published: June 2019

Somatostatin secreted from pancreatic delta-cells is a strong paracrine inhibitor of both insulin and glucagon secretion in islets. However, little is known about the regulatory mechanisms of delta cells. This is mainly due to the scarcity of these cells (∼5-10% of islet cell population) and difficulties in maintaining their morphology and function after cell dispersion. Here, we developed an optogenetic approach, through tissue-specific expression of light-sensitive channels in delta cells, to investigate the paracrine modulation of alpha/beta cells by delta cells within intact islets. We generated a mouse model using Cre-loxp recombination to enable the specific expression of a light-sensitive cation channel Channelrhodopsin-2 (ChR2) in the pancreatic delta cells (SST-ChR2 mouse). In the presence of 1 mM glucose (when ?-cells are not electrically active), light activation of ChR2 (with 470 nm LED light) rapidly depolarised delta- cells (from -66±4 mV to -19±2 mV, n=4). Similar depolarising effect was observed in delta-cells exposed to 10 mM glucose (from -59±5 mV to -19±4 mV, n=4). Delta-cells activation with light transiently repolarised alpha cells by 5 mV (n=2) at 1 mM glucose and beta cells by 4 mV (n=3) at 10 mM glucose, which correlated with a mild decrease in intracellular Ca2+ concentration. Optoactivation of delta-cells inhibited glucagon secretion in islets exposed to 1 mM glucose by 48%. Whilst not affecting that at 20 mM glucose. Interestingly, despite the effects on beta-cell membrane potential, light exposure to SST-ChR2 islets did not affect insulin secretion stimulated by 20 mM glucose, possibly suggesting that insulin secretion is already maximally inhibited by glucose-induced somatostatin secretion. We propose that the SST-ChR2 mouse model represents a powerful tool for studying spatial and temporal paracrine crosstalk between different islet cells and the role of somatostatin in islet hormone secretion.

Disclosure

H. Dou: None. C.A. Miranda: None. Q. Zhang: None. P. Rorsman: None. J. Tolö: None.

Funding

Swedish Research Council
344-LB: A Highly Specific Chemiluminescent Assay That Accurately Measures Human and Rodent Glucagon
Authors: CAILLOUETTE CHRISTIANN , MCDERMOTT BRENDA K. , CACICEDO JOSE M. , BELL BETHANY , WISHERD CHRIS
Published: June 2019

Glucagon is a hormone generated as a result of post translational modifications during proglucagon processing. The hormone's amino acid sequence is found in several proglucagon peptides, including the hormones glicentin and oxyntomodulin. In addition, glucagon’s sequence is similar to incretin hormones such as glucagon-like peptide-1 (GLP-1). The similar sequence homology between glucagon and these peptide hormones has created challenges in specifically measuring glucagon concentrations. Current commercially available glucagon assays have been proven to cross-react with oxyntomodulin, glicentin, and other proglucagon peptides. In addition, researchers often report higher cross-reactivity values than the manufacturers, which further complicates accurately measuring glucagon levels. To address this need, ALPCO has developed the STELLUX® Chemi Glucagon ELISA for the quantitative determination of glucagon in EDTA plasma and cell culture samples. This assay has an excellent sensitivity and is capable of measuring post-prandial glucagon levels in both rodents and humans. Most importantly, this assay specifically measures glucagon without any cross-reactivity to other proglucagon peptides including glicentin and oxyntomodulin. In the current study, ALPCO’s ELISA was compared to competitor A’s ELISA to further investigate how differences in specificity contribute to final calculated concentrations of the analyte. A panel of 16 samples of human, mouse, and rat EDTA plasma were assayed on both products and an overall R2 of 0.988 and slope of 1.337 was shown. The consistently higher recovery in values using the competitor ELISA may be explained through its known cross-reactivity with oxyntomodulin and/or glicentin. However, the correlation between the two assays would allow for a seamless transition from the competitor ELISA to the ALPCO ELISA within or between projects.

Disclosure

C. Caillouette: Employee; Self; Alpco. B.K. McDermott: None. J.M. Cacicedo: Employee; Self; Alpco. B. Bell: Employee; Self; Alpco. C. Wisherd: Employee; Self; Alpco.
346-OR: Primary Care Implementation Study to Increase Diabetes Prevention Program Referrals
Authors: KECK JAMES W. , ROPER KAREN L. , THOMAS ALISHA , HIERONYMUS LAURA
Published: June 2019

Background: Intensive lifestyle change programs effectively prevent or delay type 2 diabetes but are underutilized. We evaluated patient and clinician prediabetes attitudes and practices and implemented strategies to increase National Diabetes Prevention Program (DPP) referrals.

Methods: The Tailored Implementation for Chronic Diseases framework guided data collection and the interventional approach of our cluster randomized implementation study across two large primary care clinics. Formative data came from clinician surveys, patient focus groups, and electronic health record (EHR) review. Thematic qualitative and descriptive quantitative analyses identified implementation opportunities. Intervention clusters (family medicine teams) received clinician detailing and EHR-guided prediabetes patient identification. All clusters (family medicine and internal medicine) had access to an electronic DPP referral process. The primary outcome was DPP referral.

Results: Focus group participants (3 groups, 15 participants) had mixed perceptions of prediabetes risk and desired personalized behavior change guidance. Surveyed clinicians (31 respondents of 45 invited) viewed prediabetes care positively, but had low DPP awareness. Baseline pre-implementation EHR data for two years (15,520 adult patients) revealed A1c screening coverage of 75.9% per national guidelines. Documentation of prediabetes occurred in 50.7% (729/1,437) of patients meeting A1c criteria. Interim analysis of DPP referrals 8 months post-intervention found 4.8% (69/1,423) of diagnosed prediabetes patients received DPP referral in intervention clusters versus 0.7% (17/2,357) of diagnosed prediabetes patients in control clusters. Patients with prediabetes in intervention clusters had 3.32 (95% CI: 0.89, 12.35) odds of receiving DPP referral after covariate and clustered data adjustments.

Conclusions: Clinician detailing and EHR patient identification increased DPP referrals.

Disclosure

J.W. Keck: None. K.L. Roper: None. A. Thomas: None. L. Hieronymus: None.

Funding

National Center for Research Resources; National Center for Advancing Translational Sciences (UL1TR001998)
35-LB: Response to Anti-VEGF Therapy in a Nonhuman Primate Model of Diabetic Macular Edema
Authors: CHIA SER MIEN , GONG LI , TIU SARAH , CONARELLO STACEY L. , BELLUM SAIRAM , PAN LINGZHEN , LEE CHEN FEI , ALI ASAD ABU BAKAR , HONG LEWIS , ZENG WEN , CHIN CHIH-LIANG , LI NINA X.
Published: June 2019

Diabetic macular edema (DME) is one manifestation of diabetic retinopathy (DR), where fluids leak from the retinal vessels into the centre of the macula, causing swelling and blurred vision. VEGF inhibitors (e.g., ranibizumab), have demonstrated clinical efficacy in treating DME; however, it is known that ∼50% of patients do not respond to anti-VEGF therapy. Therefore, DME remains an unmet medical need. To discover novel therapies for DME, animal models that recapitulate clinical phenotypes and validated with anti-VEGF drugs will be of importance. Rodent models of DR have been developed using chemical or dietary induction to mimic the pathophysiological features observed in human. However, differences in the structural and biochemical characteristics of the visual system between rodents and humans hamper their clinical translation. Herein, we aimed to determine the effect of intravitreal administration of ranibizumab in aged, spontaneously dysmetabolic non-human primate with increased average retinal thickness (329 ± 6 µm, vs. age-matched controls 299 ± 10 µm). Seven of them showed signs of non-proliferative DR (NPDR) with presence of intra-retinal cysts, exudates or micro-aneurysms. Changes in retinal thickness and vascular leakage were measured by optical coherence tomography and fluorescein angiography, respectively. Plasma and vitreous levels of VEGF were also determined. Longitudinal data measured over 3-mo. period demonstrated modest, statistical insignificant reduction in average retinal thickness, plasma and vitreous VEGF levels. Some NPDR animals did showed potential improvement in vascular leakage. Considering anti-VEGF drugs are mostly effective in severe DR/DME patients, our results might be reconciled with the early stage of disease condition ascribed to these animals. Further investigation is needed to better understand heterogeneity of individual animal’s drug response and the relationship among imaging, plasma, and vitreous readouts in a longitudinal manner.

Disclosure

S. Chia: None. L. Gong: None. S. Tiu: Employee; Self; Merck Sharp & Dohme Corp. S.L. Conarello: None. S. Bellum: None. L. Pan: None. C. Lee: None. A. Abu Bakar Ali: Employee; Self; Merck & Co., Inc. L. Hong: Employee; Spouse/Partner; Illumina, Inc. Employee; Self; Merck Sharp & Dohme Corp. Stock/Shareholder; Spouse/Partner; Illumina, Inc. Stock/Shareholder; Self; Merck Sharp & Dohme Corp. W. Zeng: None. C. Chin: None. N.X. Li: Employee; Self; Merck & Co., Inc.
355-OR: Is Classification of GDM Phenotypes Dependent on Ethnicity?
Authors: GIBBONS KRISTEN S. , MCINTYRE DAVID , MA RONALD C. , TAM WING , MADSEN LENE R. , SACKS DAVID A. , CATALANO PATRICK
Published: June 2019

Clinical experience suggests that diverse clinical phenotypes exist within the broader diagnosis of GDM. Recent published analysis from a single center outlined heterogeneity in GDM with respect to insulin secretion and sensitivity, defining four GDM phenotypes: 1) GDMsecr (<25th centile HOMA-β for non-GDM); 2) GDMsens (<25th centile Matsuda Index for non-GDM); 3) GDMmixed (both GDMsecr and GDMsens); 4) no defect (neither GDMsecr and GDMsens). Classification using these phenotypes is associated with adverse outcomes. It is unknown whether adjustment for ethnicity may provide stronger associations with outcome prediction. Using data from 5 centers in the HAPO study, GDM women were classified into one of four phenotypes in two ways: 1) whole sample cut-offs; and 2) ethnic-specific glycemic thresholds. Descriptive characteristics were compared between the five groups (four GDM phenotypes + non-GDM), and multivariable analysis adjusted for BMI, center and key demographic and clinical characteristics. Of the 6128 women, 2442 (40%) were caucasian, 294 (4.8%) black, 1556 (25.4%) Hispanic, 1616 (26.4%) Asian and 220 (3.6%) other ethnicity; ethnicity was closely related to study center. Seventeen percent were classified as GDM (n=1047), with slightly higher GDM frequency for black (20.1%) and Hispanic women (23.3%). There was 83.9% agreement between whole-sample and ethnic-specific classification into GDM phenotypes. There was a significant relationship (p<0.05) between one or more GDM phenotypes and LGA, primary CS, neonatal hyperinsulinemia and/or fetal adiposity. Despite minor changes in the adjusted odds ratios, there were no statistically significant changes in the relationship between GDM phenotype and outcome when comparing whole sample cut-offs and ethnic-specific cut-offs. Where available, ethnic-specific cut-offs should be used to define GDM phenotype to assist in identifying GDM women at higher risk of adverse outcome, however whole-sample cut-offs can be used with confidence in their absence.

Disclosure

K.S. Gibbons: None. D. McIntyre: None. R.C. Ma: Advisory Panel; Self; Boehringer Ingelheim International GmbH. Research Support; Self; AstraZeneca, Bayer AG, Pfizer Inc. Stock/Shareholder; Self; GemVCare. Other Relationship; Self; AstraZeneca. W. Tam: None. L.R. Madsen: None. D.A. Sacks: None. P. Catalano: None.
356-OR: Effects of First Trimester Exercise on Pregnancy Hyperglycemia and GDM
Authors: EHRLICH SAMANTHA F. , NEUGEBAUER ROMAIN , FENG JUANRAN , HEDDERSON MONIQUE M. , FERRARA ASSIAMIRA
Published: June 2019

Structured, exercise-only interventions reduce the odds of GDM, but motivated trial participants are likely unrepresentative. Studies of free living exercise in population-based cohorts are needed and causal inference methods, which emulate randomized trials under specific a priori assumptions, represent the best alternative for observational data. This study estimates the causal effects of first trimester exercise on the risks of abnormal screening after a 50-OGTT, GDM diagnosed by the Carpenter-Coustan criteria, and abnormal glucose according to the Carpenter-Coustan thresholds for the 100-g OGTT. Data come from PETALS, a prospectively followed pregnancy cohort (n= 2,070, 70% from minority racial-ethnic groups) receiving care at Kaiser Permanente Northern California in 2013-2017. A Pregnancy Physical Activity Questionnaire was completed at 12.8 weeks gestation, on average (SD 2.5). Targeted Maximum Likelihood with data-adaptive estimation (a.k.a., machine learning) of propensity scores and outcome regression with recognized confounders (e.g., prepregnancy BMI, diet, education) was used to obtain causal risk differences for all women having exercised versus not. Exercise was defined as performing any amount of vigorous intensity exercise or meeting the cohort’s 75th percentile for moderate to vigorous intensity exercise (MVPA; ≥ 13.3 MET hours per week). The prevalence of abnormal screening was 23.8% and GDM 6.2%. Any participation in vigorous exercise significantly decreased the risk of GDM by 1.6 fewer cases per 100 women, and abnormal 1-hour and 2-hour OGTT values by 2.7 and 1.8 fewer cases, respectively, per 100 women. Meeting the 75th percentile for MVPA significantly decreased the risks of abnormal screening and abnormal 2-hour OGTT values by 5.2 and 2.5 fewer cases per 100 women, respectively. Findings suggest that, during the first trimester, any amount of vigorous intensity exercise or a high volume of moderate to vigorous intensity exercise reduces hyperglycemia later in pregnancy.

Disclosure

S.F. Ehrlich: None. R. Neugebauer: None. J. Feng: None. M.M. Hedderson: None. A. Ferrara: None.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (K01DK105106, P30DK092924); National Institute of Environmental Health Sciences (R01ES019196)
361-OR: ER Stress Attenuation Is Involved in PAHSA-Induced Reduction of T1D in Nonobese Diabetic (NOD) Mice
Authors: SYED ISMAIL , DE CELIS MARIA FERNANDEZ RUBIN , MOHAN JAMES F. , MORAES-VIERIA PEDRO M. , VIJAYAKUMAR ARCHANA , NELSON ANDREW T. , SIEGEL DIONICIO , SAGHATELIAN ALAN , MATHIS DIANE , KAHN BARBARA
Published: June 2019

Palmitic Acid esters of Hydroxy Stearic Acids (PAHSAs) are endogenous lipids with antidiabetic and anti-inflammatory effects. We found that PAHSAs protect against T1D by attenuating autoimmune responses and by direct effects on islets. We aimed to determine the mechanisms by which PAHSAs directly promote β-cell survival. Daily oral gavage of PAHSAs in NOD mice starting at 4 or 13 weeks of age delays T1D onset and reduces T1D incidence from 82-90% of mice with vehicle to 35-40% of mice receiving PAHSAs. PAHSA treatment reduces leukocyte infiltration into islets by 50% and reduces T cell activation. PAHSA-treated mice had greater β-cell area relative to total islet area (vehicle 60±7 vs. PAHSA 77±1). PAHSAs enhance β-cell proliferation in NOD mice 5 fold vs. vehicle. PAHSA-treated NOD mice pancreata have lower ER stress markers, CHOP and XBP-1 (vehicle 68±12 vs. PAHSA 42±3), and higher insulin (vehicle 12±2 vs. PAHSA 17±1) immunostaining intensities per β-cell area. PAHSAs attenuate thapsigargin-induced PARP cleavage by 55% in human islets, and JNK1/2 phosphorylation by 40% in MIN6 cells. Also, PAHSAs attenuate apoptotic and necrotic β-cell death under cytokine stress and increase β-cell viability by 34% and proliferation by 31% (p<0.002). Since GLP-1 receptor (GLP-1R) antagonism causes β-cell death and G-protein coupled receptor GPR40 plays a vital role in β-cell function, we assessed if PAHSA beneficial effects on β-cell survival involve these pathways. In vitro, GLP-1R antagonism lowered PAHSA protective effects on β-cell viability by 53% and proliferation by 44% (p<0.005) under cytokine stress but GPR40 antagonism had no effect.

Conclusion: In addition to attenuating immune responses, PAHSAs delay the onset and reduce T1D incidence in NOD mice through direct effects. PAHSAs directly reduce cytokine-induced β-cell death and increase cell proliferation in autoimmune diabetes through mechanisms involving ER stress reduction. This appears to be mediated in part by GLP-1R and not by GPR40.

Disclosure

I. Syed: None. M. Fernandez Rubin de Celis: None. J.F. Mohan: None. P.M. Moraes-Vieria: None. A. Vijayakumar: None. A.T. Nelson: None. D. Siegel: None. A. Saghatelian: None. D. Mathis: None. B. Kahn: Advisory Panel; Self; Alterna Therapeutics, Inc., American Diabetes Association, Harrington Discovery Institute, Janssen Research & Development. Consultant; Self; Ironwood Pharmaceuticals, Inc. Research Support; Self; National Institute of Diabetes and Digestive and Kidney Diseases.

Funding

National Institutes of Health (R01DK43051, P30DK57521 to B.K.), (R01DK106210 to B.K., A.S.), (K01DK118041 to I.S.); JPB Foundation (to B.K., D.M.); Deutsche Forschungsgemeinschaft (to M.F.R.)
364-OR: Beta-Cell Glucose-Regulated Micropeptide 1 (BGRM1) Controls Cellular Homeostasis in Pancreatic Beta Cells
Authors: LI MARK , SHAO FAN , SWEAT MASON E. , QIAN QINGWEN , GUO YUWEI , STEPHENS SAMUEL B. , IMAI YUMI , YANG LING , CAO HUOJUN
Published: June 2019

Accumulating evidence demonstrates that certain types of long-noncoding RNAs (lncRNA) encode very short open reading frames, called micropeptides. By regulating larger protein complexes, these micropeptides can regulate fundamental biological processes such as skeletal muscle development and cell migration. However, the ability of micropeptides to maintain cellular and metabolic homeostasis in islets is unknown. Using a bioinformatics approach, we comprehensively analyzed the protein-coding potential of lncRNAs that are expressed in the human pancreas, and identified more than 30 that likely encode micropeptides. We further characterized one conserved IncRNA that encodes a 65-amino-acid micropeptide, which we named beta cell glucose regulated micropeptide 1 (BGRM1). We found that BGRM1 expression was altered in islets from obese or diabetic humans and mice. Overexpression of BGRM1 elevated glucose-stimulated insulin production in INS-1 cells and in islets from humans and mice. BGRM1 promotes endoplasmic reticulum (ER) calcium efflux and enhances cytosolic calcium levels, which suggests it mediates insulin production is in part by modulating intracellular calcium homeostasis. This notion is further supported by our mass spectra analysis that reveals several BGRM1 binding partners involved in ER calcium homeostasis in beta cells. Notably, BGRM1 is localized in the ER and protects beta cells from ER stress. Taken together, our study provides the first evidence that lncRNA encoded micropeptides play a critical role in pancreatic beta cell function. These results provide a foundation on which to perform future comprehensive analyses of micropeptide function and pathophysiological impact on diabetes.

Disclosure

M. Li: None. F. Shao: None. M.E. Sweat: None. Q. Qian: None. Y. Guo: None. S.B. Stephens: None. Y. Imai: None. L. Yang: None. H. Cao: None.
367-P: Severe Hypoglycemia and Risk of Falls in Type 2 Diabetes: The Atherosclerosis Risk in Communities (ARIC) Study
Authors: LEE ALEXANDRA K. , JURASCHEK STEPHEN P. , WINDHAM B. GWEN , LEE CLARE , SHARRETT A. RICHEY , CORESH JOSEF , SELVIN ELIZABETH
Published: June 2019

Diabetes is common among older adults and is associated with greater risk of falls, which can be fatal in this population. One hypothesized link between diabetes and falls is hypoglycemia. However, this has not been evaluated in an older, type 2 diabetes population. We included 1186 ARIC participants with diabetes at Visit 4 (1996-1998) followed through 2013 for severe hypoglycemia and falls. We identified severe hypoglycemia with ICD-9 codes in claims for hospitalization, emergency department and ambulance use. Falls were based on E-codes in inpatient and outpatient claims; secondary outcomes were hospitalized falls and falls with fracture. We used adjusted Cox regression models to evaluate the association of severe hypoglycemia as a time-varying exposure with risk of subsequent fall. Participants had a mean age of 64, 54% female, 32% black; 14 had hypoglycemia prior to baseline and 135 had a severe hypoglycemic episode during follow-up. The crude incidence rate of falls without severe hypoglycemia was 2.17 per 100 person-years (PY) (95% CI: 1.93-2.44) and 8.81 per 100PY (6.73-11.53) with severe hypoglycemia. After adjustment, hypoglycemia was associated with an over two-fold greater risk of falls (Table). Fall history and risk should be considered when deciding glycemic goals and medication use, as hypoglycemia may increase fall risk.

Disclosure

A.K. Lee: None. S.P. Juraschek: None. B. Windham: None. C. Lee: Consultant; Self; XOMA Corporation. Research Support; Self; Eiger BioPharmaceuticals. A. Sharrett: None. J. Coresh: None. E. Selvin: None.

Funding

National Institutes of Health
382-P: Insulin Requirements after Hospital Discharge in Patients with Type 2 Diabetes
Authors: FAYFMAN MAYA , LEROITH DEREK , PASQUEL FRANCISCO J. , ANZOLA ISABEL , URRUTIA MARIA A. , WANG HEQIONG , UMPIERREZ GUILLERMO E.
Published: June 2019

Changes in insulin requirements after hospital discharge in insulin-treated patients with type 2 diabetes (T2D) are not known. We conducted a pooled analysis of 4 randomized clinical trials with 3-month follow-up data to determine changes in insulin requirement after discharge. These studies followed a discharge algorithm based on admission HbA1c to guide outpatient insulin therapy. A total of 255 insulin-treated patients (age: 55.6 year, BMI 34.6 kg/m2, duration DM: 11.2±8 year) were discharged on glargine + oral antidiabetic (OAD) agents (75%), glargine + exenatide (4%), or basal bolus (21%). Patients with HbA1c <7% (11.4%) were discharged on the same outpatient therapy. Those with an HbA1c between 7% and 9% (37.2%) were discharged on glargine at 50% of hospital TDD + their outpatient OAD agents. Those with an HbA1c >9% (51.4%) were discharged on glargine at 80% of hospital TDD in combination to OAD or with basal bolus regimen. Treatment was adjusted to achieve a target HbA1c level <7%. The primary outcome was change in insulin total daily dose (TDD) at 3 months after discharge. Changes in HbA1c, hypoglycemia, insulin TDD, and change in insulin requirements at 3 months of follow-up are shown in Table.

In summary, insulin TDD requirements vary greatly after hospital discharge in patients with T2D. Most patients required frequent insulin adjustments to maintain glycemic control and to avoid hypoglycemia after hospital discharge.

Disclosure

M. Fayfman: None. D. LeRoith: Advisory Panel; Self; AstraZeneca, MannKind Corporation. F.J. Pasquel: Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Merck & Co., Inc. I. Anzola: None. M.A. Urrutia: None. H. Wang: None. G.E. Umpierrez: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc. Research Support; Self; AstraZeneca, Merck 0026 Co., Inc., Novo Nordisk Inc., Sanofi US.
389-P: Comparison of Hormonal Response to a Mixed-Meal Challenge in Individuals with Hypoglycemia after Sleeve Gastrectomy vs. Gastric Bypass
Authors: LEE CLARE , BROWN TODD , SCHWEITZER MICHAEL , MAGNUSON THOMAS , CLARK JEANNE
Published: June 2019

Objective: Exaggerated post-prandial incretin and insulin responses are well-documented in post-bariatric surgery hypoglycemia (PBH) after Roux-en-Y gastric bypass (RYGB). However, less is known about PBH after sleeve gastrectomy (SG). Thus, we sought to compare meal-stimulated hormonal response in those with PBH after SG vs. RYGB.

Methods: We enrolled 20 RYGB (7 with and 13 without PBH) and 23 SG (12 with and 11 without PBH) who underwent bariatric surgery at our institution. PBH was defined as a postprandial interstitial or plasma glucose <55 mg/dl on continuous glucose monitor (5-days as outpatient, Dexcom) or 4-hour mixed meal tolerance test (MTT). Plasma samples from MTT were used to measure glucose, insulin, glucagon-like peptide (GLP)-1 and glucose-dependent insulinotropic polypeptide (GIP). We used Kruskal Wallis Test to compare the difference in glucose or hormones across 4 groups (with and without PBH after SG or RYGB).

Results: Participants (N=43) were on average 5 years since surgery, with mean age of 50 years, mean preoperative BMI of 48 kg/m2, 81% female, 61% Caucasian, 53% post SG. There were no differences in fasting glucose (p=0.38) or fasting insulin (p=0.34) across the 4 groups. Among those with PBH, the SG group showed a lower peak glucose (131.8 mg/dl, p<0.01), similar nadir glucose (59.6 mg/dl, p=0.18), peak insulin (68.7 mU/L, p<0.01) and peak GLP-1 (15.3 pM, p<0.01) and differed in overall hormonal response (AUC 0-240min) with lower insulin (3956.1 mU/L/min, p<0.01), lower GLP-1 (2498.9 pM/min, p<0.01) and higher GIP (51335.4 pM/min, p=0.05) compared to RYGB with PBH group.

Conclusion: Among those with PBH, the SG group showed less glycemic excursion and different hormonal profiles including lower insulin, GLP-1 and higher GIP responses to MTT compared to the RYGB group. Future studies are needed to better understand the differential contribution of insulin and non-insulin mediated mechanisms behind PBH after SG vs. RYGB.

Disclosure

C. Lee: Consultant; Self; XOMA Corporation. Research Support; Self; Eiger BioPharmaceuticals. T. Brown: None. M. Schweitzer: Consultant; Self; Ethicon, Inc. T. Magnuson: None. J. Clark: None.

Funding

National Institutes of Health
391-P: Hypoglycemia Reductions with the Dexcom G6 CGM System’s Predictive Alert
Authors: DERDZINSKI MARK , WELSH JOHN , PUHR SARAH , WALKER TOMAS C. , PARKER ANDREW , JIMENEZ ANNIKA
Published: June 2019

Background: The Dexcom G6 continuous glucose monitoring (CGM) system differs from Dexcom’s earlier G5 system in that G6 includes a predictive “Urgent Low Soon” (ULS) alert that notifies users when an estimated glucose value (EGV) ≤55 mg/dL is predicted in the next 20 minutes. The effect of the ULS alert on the distribution of EGVs was evaluated in the context of traditional threshold alerts.

Methods: We identified individuals who had used G5 and transitioned to G6 between 5/1/2018 and 10/31/2018. Evaluable data were from a subset of 4083 users who had maintained low threshold alerts at either 70 or 80 mg/dL, who used a smartphone to view and upload ≥30 days of data from each system, and who maintained the G6 ULS alert in its default (enabled) state.

Results: Use of the 80 mg/dL low threshold alert was associated with higher mean EGVs, less hypoglycemia, and more hyperglycemia than use of the 70 mg/dL low threshold alert (Table). Over 97% of the G6 systems were used with the ULS feature enabled, and the ULS alert was activated less than once daily. At either low threshold setting, the transition to G6 was associated with reductions in hypoglycemia (<55 and <70 mg/dL) and severe hyperglycemia (>250 mg/dL).

Conclusions: When used in the context of traditional low threshold alerts, the predictive ULS alert may enable timely and appropriate interventions that contribute to further reductions in hypoglycemia among CGM-experienced users.

Disclosure

M. Derdzinski: Employee; Self; Dexcom, Inc. J. Welsh: Employee; Self; Dexcom, Inc. S. Puhr: None. T.C. Walker: Employee; Self; Dexcom, Inc. A. Parker: Employee; Self; Dexcom, Inc. A. Jimenez: Employee; Self; Dexcom, Inc.
399-P: Deintensification of Diabetes Treatment in Elderly Patients with Type 2 Diabetes Mellitus
Authors: PIRELA DANIELA V. , GARG RAJESH
Published: June 2019

The prevalence of type 2 diabetes mellitus (T2DM) is increasing, especially in the elderly population. Many of these patients have co-morbidities like renal insufficiency, cognitive impairment and lack of social support, increasing the risk of hypoglycemia. Moreover, the benefits of tight glycemic control have not been established in the elderly. Therefore, the American Diabetes Association recommends relaxed glycemic goals (HbA1c ∼8%) in the elderly population. De-intensification of diabetes treatment is recommended to prevent potential harm. We conducted a retrospective study to evaluate the rate of de-intensification of antidiabetic treatment in patients aged ≥75 years with HbA1c ≤7% at the time of their clinic visits. All patients with ≥2 clinic visits over 1-year period at a major academic diabetes center were included. Out of 1,417 unique patients treated during 2017, 174 were ≥75 years old on the day of their last clinic visit. Out of these, 80 patients had an HbA1c ≤7%. Medical records of these 80 patients were manually reviewed for comorbidities, hypoglycemic episodes and drug therapy. A mention of de-intensification of antidiabetic treatment was found in physicians’ notes in only 12 cases. After excluding those with type 1 diabetes, inadequate documentation or controlled on medications without hypoglycemia potential, we found 36 patients treated with a sulfonylurea drug or insulin. Only 10 (27%) patients were advised to reduce the dose of sulfonylurea drug or insulin after an HbA1c <7% was noted. Out of patients receiving a sulfonylurea drug or insulin, 17 had at least one episode of hypoglycemia before the visit. Even among patients with documented hypoglycemia, only 7 (41%) were advised to de-intensify therapy. Our study suggests that de-intensification of antidiabetic medications is infrequent despite the potential harm of hypoglycemia in elderly patients with T2DM. Strategies need to be developed to prevent overtreatment of diabetes in the elderly patients.

Disclosure

D.V. Pirela: None. R. Garg: None.
401-P: Acute Low Glucose Alters Human Primary Astrocyte Expression of Endoplasmic Reticulum Stress and Mitochondrial Associated Genes, Which Is Blunted after Recurrent Low Glucose
Authors: WEIGHTMAN POTTER PAUL G. , WASHER SAM J. , JEFFRIES AARON , DEMPSTER EMMA L. , BEALL CRAIG
Published: June 2019

Astrocytes are important regulatory cells in the brain that support neuronal function. However, their role in hypoglycemia counterregulation is poorly understood. Moreover, astrocytic transcriptional responses to hypoglycemia and the mechanisms by which recurrent hypoglycemia (RH) suppresses counterregulation are not understood. Using human primary astrocytes (HPA) in vitro we tested whether recurrent low glucose (RLG), to model RH, would regulate differential gene expression (DGE). HPA cells were exposed to 3-hour bouts of 2.5 or 0.1 mM glucose over 4 days and mRNA expression was quantified using RNA-sequencing and DGE measured using DESeq2. Acute low glucose (LG) differentially expressed 31 genes including the downregulation of mitochondrial genes (mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 2, subunit 4 and subunit 4L; MT-ND2, MT-ND4 and MT-ND4L) and endoplasmic reticulum stress associated genes (X-box binding protein 1; XBP1, and heat shock protein family A; Hsp70, member 1A, and member 5; HSPA1A and HSPA5). However, neither antecedent RLG (aRLG) nor RLG treated cells have significantly altered gene expression compared to control. LG treatment decreased the expression of XBP1 and increased thioredoxin interacting protein (TXNIP) and exostosin Like glycosyltransferase 3 (EXTL3) which were also similarly altered by low glucose compared to aRLG.MT-ND2, MT-ND4 and MT-ND4L genes are associated with diabetes and neurodegeneration. Furthermore, LG-induced reduction of XBP1 may also increase fatty acid oxidation by disinhibiting inositol-requiring kinase 1α. This corroborates previous work indicating low glucose increases fatty acid utilisation in astrocytes and the hypothalamus. While the functional impact of differential gene expression needs assessing, this provides evidence that these genes may be important in astrocytic responses to hypoglycemia.

Disclosure

P.G. Weightman Potter: None. S.J. Washer: None. A. Jeffries: None. E.L. Dempster: None. C. Beall: None.

Funding

Novo Nordisk UK Research Foundation; Diabetes UK; Mary Kinross Charitable Trust
407-P: Growth Differentiation Factor 15, Coronary Atherosclerosis and Diabetic Kidney Disease in Adults with Type 1 Diabetes (T1D)
Authors: BJORNSTAD PETTER , SIPPL RACHEL M. , REWERS MARIAN , SNELL-BERGEON JANET K.
Published: June 2019

Objective: In health, circulating growth differentiation factor (GDF)-15 is low, and concentrations are thought to increase rapidly in response to cardiac and renal injuries. GDF-15 is secreted in response to inflammation, oxidative stress and hypoxia, and therefore may be a biomarker of subclinical vascular disease. Yet, the relationships between GDF-15, coronary artery disease and diabetic kidney disease (DKD) remain incompletely understood. Accordingly, the objective of this study was to delineate these relationships in adults with T1D.

Methods: Participants with (n=377, HbA1c 7.8±1.3%, duration 37.1±8.6 years) and without T1D (n=456) in the Coronary Artery Calcification in type 1 diabetes (CACTI) study were assessed for serum GDF-15, coronary artery calcification (CAC) measured using 128-slice spiral CT, urinary albumin-to-creatinine ratio (UACR) and eGFR calculated by CKD-EPI creatinine. Impaired GFR was defined as eGFR <60mL/minutes/1.73m2, albuminuria as UACR ≥30 mg/g, high and very high CAC score as ≥100 and ≥300 AU. Multivariable (age, sex, HbA1c, and antihypertensive medication use) logistic models were applied to examine the relationships.

Results: Participants with T1D had greater GDF-15 concentrations than nondiabetics (666.4 [95% CI 633.9-700.5] vs. 579.1 [558.7-600.4] ng/l, p<0.0001). In participants with type 1 diabetes, higher GDF-15 was associated with greater odds of impaired GFR (OR: 4.40, 95% CI 2.51-7.73, p<0.0001), albuminuria (2.47, 1.60-3.80, p<0.0001), high CAC (1.67, 1.16-2.41, p=0.006) and very high CAC (1.62, 1.01-2.58, p=0.04) in multivariable models (per 1 SD increase in natural log GDF-15).

Conclusion: In this cross-sectional analysis, GDF-15 was strongly associated with DKD and coronary atherosclerosis in adults with T1D, independent of glycemic control. As a biomarker, GDF-15 holds promise to aid in risk stratification and clinical trial enrichment.

Disclosure

P. Bjornstad: Advisory Panel; Self; Horizon, XORTX. Consultant; Self; Bayer US, Boehringer Ingelheim International GmbH, Bristol-Myers Squibb Company. R.M. Sippl: None. M. Rewers: None. J.K. Snell-Bergeon: None.

Funding

National Institutes of Health; JDRF
41-LB: Lipoprotein Subfractions Are Associated with Diabetic Microvascular Disease among 9,795 Patients in the FIELD Trial
Authors: TOTH PETER P. , KEECH ANTHONY C. , JANUSZEWSKI ANDRZEJ S. , OCONNELL RACHEL L. , LI LIPING , SULLIVAN DAVID , TASKINEN MARJA-RIITTA , DRURY PAUL L. , WATTS GERALD FRANCIS , BEST JAMES D. , ANSQUER JEAN CLAUDE , JONES STEVEN R. , JENKINS ALICIA J.
Published: June 2019

Background: In the FIELD trial, a 5-year randomized double-blind placebo-controlled trial of fenofibrate vs. placebo in 9,795 adults with type 2 diabetes (T2D), the only standard lipid parameter correlating with microvascular (renal) events was triglycerides. Given the high prevalence of diabetic microangiopathy, we explored associations between lipoprotein subfractions and nephropathy, retinopathy, microvascular amputations (MiAmp) and neuropathy.

Methods: We performed ultracentrifugation using the vertical autoprofile (VAP, Atherotech) on plasma (baseline and after 6 weeks of fenofibrate). Analyses were performed using Cox proportional hazards and logistic regression for new on-study events. Results were adjusted for gender and fenofibrate or placebo allocation.

Results: HDL related analytes (HDL-C, HDL3-C, apo A1, apoA2) correlated with reduced risk for neuropathy, nephropathy, and MiAmp. Buoyant LDL (LDL1-C) and densest LDL (LDL4-C) correlated negatively with neuropathy and positively for MiAmp, respectively. Triglycerides and apo C3 increased neuropathy and nephropathy risk. VLDL species correlated with increased MiAmp and retinopathy risk.

Conclusions: VAP identifies multiple lipoprotein subclasses and VAP subclass/apoprotein ratios associated with diabetic microangiopathy. Many were improved with fenofibrate.

Disclosure

P.P. Toth: Consultant; Self; Amarin Corporation, Amgen Inc., AstraZeneca, Kowa Pharmaceutical Europe Co. Ltd., Novo Nordisk Inc. Speaker’s Bureau; Self; Amarin Corporation, Amgen Inc., Merck & Co., Inc., Novo Nordisk Inc., Regeneron Pharmaceuticals, Sanofi US. A.C. Keech: None. A.S. Januszewski: None. R.L. OConnell: None. L. Li: None. D. Sullivan: None. M. Taskinen: Advisory Panel; Self; Novo Nordisk A/S. Consultant; Self; Akcea Therapeutics, Chiesi USA, Inc. Research Support; Self; Amgen Inc., Novo Nordisk A/S. Speaker’s Bureau; Self; Amgen Inc. P.L. Drury: None. G.F. Watts: None. J.D. Best: Consultant; Self; Abbott. J. Ansquer: Research Support; Self; Abbott, Mylan. S.R. Jones: 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.
410-P: An Impaired Mitophagy-Lysosome System Contributes to Hyperglycemia Cardiotoxicity
Authors: KOBAYASHI SATORU , HUANG YUAN , KOBAYASHI TAMAYO , LI CAIRONG , CAI FEI , LIANG QIANGRONG
Published: June 2019

Mitochondrial dysfunction plays an important role in diabetic heart damage. A healthy pool of mitochondria is maintained through a number of quality control mechanisms including mitophagy that degrades dysfunctional mitochondria through the lysosome. In the present study, we investigated the function of mitophagy-lysosome system in the diabetic heart and in cardiomyocytes cultured under high glucose. Streptozotocin-induced diabetes initiated mitophagy in the mouse heart but did not lead to its completion in the lysosome. Overexpression of the E3 ligase Parkin accelerated mitophagy flux and reduced diabetic cardiac injury. In contrast, Parkin gene deletion had the opposite effects, suggesting an essential role for mitophagy in maintaining cardiac homeostasis in diabetes. Lysophagy is the degradation of injured lysosomes by healthy lysosomes which is extremely important for all forms of autophagy. Using a novel dual fluorescent lysosome reporter, we showed that diabetes triggered lysosomal injury but reduced lysophagy flux, leading to the accumulation of injured lysosomes and the release of lysosomal enzymes such as cathepsin D. High glucose had similar effects in cultured cardiomyocytes. Enhancing lysophagy not only reduced high glucose toxicity but also accelerated mitophagy flux. Together, these results suggest that lysosomal dysfunction accounts at least partially for the reduced mitophagy flux and increased diabetic heart damage and that restoring lysosomal function may enhance mitochondrial quality control and reduce hyperglycemia cardiotoxicity.

Disclosure

S. Kobayashi: None. Y. Huang: None. T. Kobayashi: None. C. Li: None. F. Cai: None. Q. Liang: None.

Funding

National Institutes of Health