bluuebunny/crossref_metadata_2025 huggingface dataset:
198-OR: The Stimulatory Effect of Glucagon on Insulin Secretion Is Glucose Dependent in Healthy Human Subjects
Authors: GRAY SARAH M. , ZHANG GUO-FANG , BENNETT WILLIAM , TONG JENNY , CAMPBELL JONATHAN , D’ALESSIO DAVID A.
Published: June 2021

Glucagon is generally considered to be a counter-regulatory hormone with a primary role to raise blood glucose concentrations by increasing endogenous glucose production (EGP). However, recent preclinical findings support a paracrine action of glucagon to act directly on pancreatic beta cells to promote nutrient-stimulated insulin secretion. In mice, the divergent actions of glucagon are dependent on glycemic status: during fasting glucagon acts predominantly at the liver to raise blood glucose, whereas in the fed state when glycemia is elevated, the insulinotropic effects predominate to lower glucose. These mechanistic findings have not been extended to human physiology. Therefore, we designed a study to test the hypothesis that in healthy humans glucagon actions are also dependent on ambient glycemia. Subjects received glucagon (100 ng/kg) during fasting euglyemia or experimental hyperglycemia (~150 mg/dl) on separate days. On both days, glycemia was maintained for 60 min prior to a glucagon infusion for an additional 60 min. Blood glucose was monitored at bedside and plasma samples were analyzed for C-peptide and di-deuterated glucose enrichment to calculate HGP. During fasting euglycemia, blood glucose was 85 mg/dl and glucagon elicited an increase to a 60 minute average of 132 mg/dl with a peak at ~156 mg/dl at the end of the infusion. Concordant with increased glycemia was an immediate increase in HGP (1.8x) and a delayed increase in C-peptide AUC (1.5x). For the hyperglycemia studies, blood glucose was maintained at 150 mg/dl before and during glucagon administration. Here, glucagon caused a rapid and robust increase in C-peptide AUC (4x) and a more gradual increase in HGP (2x). This glycemic-dependent behavior of glucagon suggests a physiologic role to promote prandial insulin secretion in healthy subjects. This raises the possibility that this incretin function of glucagon plays a role in β-cell function in diabetic subjects.

Disclosure

S. M. Gray: None. G. Zhang: None. W. Bennett: None. J. Tong: None. J. Campbell: None. D. A. D’alessio: Advisory Panel; Self; Eli Lilly and Company, Sun Pharmaceutical Industries Ltd., Research Support; Self; Eli Lilly and Company, Merck & Co., Inc.

Funding

National Institutes of Health (F32DK121420, R01DK101991)
21-LB: Development and Validation of the Barriers and Supports Evaluation for Working-Age Adults with Type 1 Diabetes
Authors: COX ELIZABETH D. , PLANALP ELIZABETH M. , KLIEMS HARALD , PALTA MARI , LECAIRE TAMARA J. , CHEWNING BETTY A.
Published: June 2021

Objective: To optimize type 1 diabetes (T1D) self-management, experts recommend tailoring care to meet people’s needs and preferences. To facilitate this tailoring, we developed and validated the Barriers and Supports Evaluation (BASES) tool to identify working-age adults’ T1D self-management barriers and supports.

Methods: Participants were 25-64 year old adults with T1D recruited from clinics and a community-based registry. Guided by Social Cognitive Theory, content analysis of 33 semi-structured interviews was used to create a comprehensive item pool of 136 items, further refined to 70 candidate items on a 5-point Likert scale through cognitive interviewing and pilot testing. To develop and validate the tool, exploratory and confirmatory factor analyses were applied to 392 participants’ survey responses to the candidate barrier and support items. Additional survey data included demographics and the Diabetes-Specific Quality of Life Scale-Revised. To evaluate concurrent validity, A1c values from medical records and quality of life (QoL) scores were regressed on domain scores.

Results: Factor analyses yielded 5 domains with a total of 30 items: (1) Cognitive Processes, (2) Costs and Insurance, (3) Learning Opportunities, (4) Family and Friend Support, and (5) Diabetes Provider Interactions. Models exhibited good to adequate fit, with Comparative Fit Index (CFI)>0.88 and Root Mean Squared Error of Approximation (RMSEA)<0.06. All domains demonstrated significant associations with A1c and QoL in the expected direction, with the exception of the Family and Friend Support domain. The Cognitive Processes domain exhibited the strongest associations with both A1c (β=0.7; 0.4-0.9) and QoL (β=-19; -21 to -17).

Conclusions: The BASES tool is brief, patient-centered, and demonstrates construct and concurrent validity. The tool could be used in clinical practice to tailor diabetes support and education to individual’s needs, improving effectiveness of services.

Disclosure

E. D. Cox: None. E. M. Planalp: None. H. Kliems: None. M. Palta: n/a. T. J. Lecaire: None. B. A. Chewning: None.

Funding

American Diabetes Association (1-18-ICTS-026 to E.D.C.)
210-OR: Cerebral Morphometric Alterations in Painless and Painful Diabetic Peripheral Neuropathy
Authors: SLOAN GORDON P. , SELVARAJAH DINESH , TEH KEVIN , SHILLO PALLAI RAPPAI , WILKINSON IAIN D. , TESFAYE SOLOMON
Published: June 2021

Aims: Neuroimaging studies have found structural alterations in brain regions involved in the somatomotor system in diabetic peripheral neuropathy (DPN) and painful-DPN (pDPN). However, most of these studies have had small cohorts of subjects, without consideration of pDPN phenotypes. Here we present the largest DPN neuroimaging study, which examines differences in brain morphology in DPN and phenotypes of painful-DPN.

Methods: 229 participants were enrolled, 177 with diabetes (46 no-DPN, 56 painless-DPN and 75 pDPN; 25 irritable [IR] and 50 non-irritable [NIR] phenotype), and 52 healthy volunteers underwent detailed clinical, neurophysiological and quantitative sensory testing (DFNS) assessments, and 3-dimensional T1-weighted brain MRI (3.0T, Phillips). Brain volumetry was performed using Freesurfer.

Results: At the post-central gyrus, in comparison with HV (1.92mm±0.11) and NoDPN (1.90mm±0.14), there was a significantly reduced cortical thickness in DPN (1.85mm±0.14), in pDPN (1.87mm±0.12) cortical thickness was reduced compared with HV. At the precentral gyrus, both DPN (2.29mm±0.16) and pDPN (2.28mm±0.16) had significantly reduced cortical thickness compared with HV (2.37mm±0.14) and NoDPN (2.36mm±0.13). At the insula, compared with HV (2.93mm±0.15) the cortical thickness was reduced in DPN (2.85mm±0.18) and pDPN (2.84mm±0.17). The cortical thickness at the pre and postcentral gyrus, and insula correlated with measures of nerve conduction. Moreover, the mean anterior cingulate cortical (ACC) thickness was significantly reduced in the IR- (2.40mm±0.23) compared to NIR-pDPN (2.58mm±0.20; p=0.003).

Conclusions: Key somatomotor brain regions have a reduced cortical thickness in patients with DPN and pDPN, which correlate with neurophysiological measures suggestive of an ascending axonopathy. Moreover, the cortical thickness at the ACC differentiated IR and NIR, suggesting neuroplasticity in this region may play a role determining clinical phenotypes in pDPN.

Disclosure

G. P. Sloan: None. D. Selvarajah: None. K. Teh: None. P. Shillo: None. I. D. Wilkinson: None. S. Tesfaye: Advisory Panel; Self; Angellini, Bayer AG, Eva Pharma, Wörwag Pharma, Speaker’s Bureau; Self; Abbott, AstraZeneca, Grunenthal Group, MSD Corporation, Novo Nordisk, Pfizer Inc.
22-LB: Use of a Novel Virtual Patient Simulation Application to Assess Providers’ Knowledge in Management of T2 Diabetes
Authors: DRAZNIN BORIS , IANCU IGAL
Published: June 2021

The goals of Type 2 diabetes (T2DM) management include achievement of glycemic, blood pressure (BP), and lipid control. All three variables must be addressed adequately in order to prevent diabetic complications. Aim: Using a proprietary smartphone-based application (APP) developed by Edocate Ltd, that simulates virtual visits, we assessed how well healthcare providers (HCPs) manage T2DM.

Materials & Methods: A total of 461 HCPs (247 MD, MD/PhD, or DO and 214 NPs) downloaded and used the APP to treat their virtual patients over multiple visits. All patients presented with poorly controlled T2DM, hypertension (HTN) and hyperlipidemia. HCPs chose the first, second and third lines of medications, made diagnostic adjustments, initiated appropriate referrals to specialists, and ordered laboratory tests of their choice. Based on their selections, the APP simulated the course of diabetes and its complications, requiring diverse management decisions on the subsequent virtual visits.

Results: In the Edocate virtual clinic, only 53% of HCPs achieved good glycemic control (A1c < 7%), 41% achieved BP control (<130/80 mmHg), and 66% prescribed high-intensity statins. NPs performed slightly but not significantly better than the physician cohort. Only 48% of HCPs checked microalbuminuria, 54% ordered creatinine and 55% ordered LDL. Interestingly, 79% of HCPs either kept or started Metformin as the first line medication. The most commonly ordered second line of medications for glycemic control was either GLP-1 receptor agonists (39%) or SGLT2 inhibitors (36%), while 23% of HCPs kept their patients on or added sulfonylurea or basal insulin (11%).

Conclusions: Despite a worldwide effort in diabetes education, the knowledge of T2DM management remains suboptimal (as assessed by the simulation APP) and underscores the need for better professional education. Innovative patient simulation-based learning applications can dramatically improve the level of competency in HCPs.

Disclosure

B. Draznin: None. I. Iancu: None.
222-LB: Canonical Wnt Signaling Regulates Beta-Cell Neogenesis from Pancreatic Duct Cells
Authors: AFELIK SOLOMON , YU ZHAN
Published: June 2021

Diabetes results from loss or insufficient numbers of insulin producing beta cells. Thus, restoration of beta cell mass can offer a lasting cure for diabetes. Physiological conditions such as obesity and pregnancy are known to induce compensatory increase in beta cell mass; suggesting the presence of an endogenous mechanism for beta cell regeneration. Significant progress has been made in understanding the regeneration of beta-cells through proliferation of existing beta-cells. In addition to proliferation of existing beta-cells, there is mounting evidence, from both animal models and human tissue, indicating that adult pancreatic duct cells can regenerate endocrine cells, including insulin producing cells. However, the molecular mechanisms governing the regeneration of pancreatic endocrine cells, especially beta cell from pancreatic duct cells remain to be defined. We have found that adult pancreatic duct cells are active in both Notch and Wnt/beta-catenin signaling. Transcriptional profiling revealed Hes1 as the predominant Notch target gene in adult mouse pancreatic duct cells. Using lineage-tracing mouse models, we found that duct-specific deletion of Hes1 in vivo resulted in the conversion of pancreatic duct cells into predominantly somatostatin+ cells. Conversely, pancreatic duct-specific deletion of the canonical Wnt signaling effector, beta-catenin, in vivo resulted in downregulation of Hes1 expression, and the conversion of pancreatic duct cells into predominantly insulin producing cells. Taken together our results demonstrate that Notch and Wnt signaling maintain the adult pancreatic duct state, with duct-derived beta-cell neogenesis requiring the loss of Wnt/beta-catenin signaling.

Disclosure

S. Afelik: None. Z. Yu: None.
225-LB: Targeting ß-Cell Endoplasmic Reticulum (ER) TALK-1 Channels to Restore Ca2+ Homeostasis and Reduce ER Stress in Diabetes
Authors: NAKHE ARYA Y. , DADI PRASANNA , WESTOVER DAVID , DAYS EMILY , DENTON JEROD , JACOBSON DAVID
Published: June 2021

Perturbations in Ca2+ homeostasis contribute to β-cell failure in diabetes, limiting insulin secretion and exacerbating hyperglycemia. TALK-1 is the most islet-restricted and most abundantly expressed K+ channel of the β-cell. ER TALK-1 channels provide K+ countercurrent for [Ca2+]ER release, thereby tuning [Ca2+]ER storage and release. During β-cell Ca2+ influx, TALK-1-enhanced [Ca2+]ER release leads to activation of the hyperpolarizing Ca2+ activated K+ channels, thus increasing the silent phase duration between Ca2+ oscillations. A gain-of-function mutation in TALK-1(L114P) causes MODY, by disrupting cytoplasmic and ER Ca2+ handling. However, the ability to probe ER TALK-1 channels as a therapeutic target to normalize β-cell Ca2+ handling and reduce ER stress in diabetes has not been determined. Here, using a high throughput fluorescence-based thallium (TI+) flux assay (z’ =0.64) in a TALK-1 overexpression cell line, we identified 80 TALK-1 selective inhibitors from a small molecule library of 50,000 compounds. 4 potent inhibitors that also inhibited the ER membrane TALK-1 channels were identified by monitoring cyclopiazonic acid-induced [Ca2+]ER release (e.g. K2P16-i7(IC50=5.3μM); 63.36% [Ca2+]ER recovery, p-value=0.02). We also tested these inhibitors for their efficacy in controlling mouse islet [Ca2+]ER storage as well as cytosolic Ca2+ oscillations. TALK-1 inhibitors significantly increased islet [Ca2+]ER storage and Ca2+ oscillation frequency (e.g.K2P16-i7; [Ca2+]ER AUC=60.9a.u., peaks/min=0.45 vs. DMSO; [Ca2+]ER AUC=49.7a.u., peaks/min= 0.17, p-value<0.05). Importantly, the inhibitors did not alter [Ca2+]ER and glucose-stimulated Ca2+ oscillation frequency in TALK-1 KO islets. In summary, we have identified the first ER TALK-1 selective inhibitors that can not only be utilized to assess the role of TALK-1 in human β-cell Ca2+ handling and GSIS, but also potentially reduce ER dysfunction during diabetes pathogenesis.

Disclosure

A. Y. Nakhe: None. P. Dadi: None. D. Westover: None. E. Days: None. J. Denton: None. D. Jacobson: None.
226-LB: Elimination of the Progesterone Receptor in ß Cells Improves ß-Cell Function and Glucose Tolerance during Pregnancy and Diet-Induced Insulin Resistance in Female Mice
Authors: DE SA PAULA MOTA , QADIR MIRZA MUHAMMAD FAHD , MAUVAIS-JARVIS FRANCK
Published: June 2021

We showed that the gonadal hormones estradiol and testosterone influence islet β-cell function and survival in a sex-specific manner via estrogen and androgen receptors expressed in islet β-cells. The progesterone receptor (PR) is a ligand-activated transcription factor and is believed to be involved in the β-cell adaptation to pregnancy. Leveraging public single-cell RNA-seq datasets we observe PR mRNA expression in α- β- and γ-cells in male and female human pancreatic endocrine cells. Using immunohistochemistry, we observe that, unlike in the uterus where PR is nuclear, PR is localized in the cytoplasm of β-cells in male and female human and mouse islets. We investigated the role of progesterone and PR in β-cell physiology in male and female mice with conditional deletion of PR in β-cells (βPRKO) by crossing PR-Lox/lox and MIP-Cre transgenic mice. Male βPRKO mice exhibited no alteration in glucose homeostasis on normal chow (NC) or following western-diet (WD)-induced insulin resistance and obesity compared to littermate PR-Lox/lox controls. Similarly, NC-fed female βPRKO mice exhibited no abnormality of glucose or insulin homeostasis compared to littermate PR-Lox/lox controls. However, during pregnancy or WD feeding, female βPRKO mice developed enhanced IP-glucose-stimulated insulin secretion, associated with improved IP glucose tolerance compared to littermate PR-Lox/lox controls. These results reveal that PR is a cytosolic receptor in β-cells, and suggest that in conditions of high insulin demand, such as pregnancy and diet-induced insulin resistance, elimination of PR action in β-cells of females improves the ability of β-cells to produce insulin and lowers blood glucose. PR may be involved in the pathogenesis of gestational diabetes.

Disclosure

P. Mota de sa: None. M. Qadir: None. F. Mauvais-jarvis: None.

Funding

National Institutes of Health (DK074970, DK107444); U.S. Department of Veterans Affairs (BX003725)
227-LB: GLP-1 Activation of HCN Channels Increases Glucose-Stimulated β- and δ- Cell Ca2+ Oscillation Frequency
Authors: ZABORSKA KAROLINA E. , JORDAN KELLI L. , DADI PRASANNA , DICKERSON MATTHEW , GRAFF SARAH M. , JACOBSON DAVID
Published: June 2021

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control human β-cell insulin secretion. Here, we examined if HCN channels impact glucagon-like-peptide 1 (GLP-1) receptor modulation of islet Ca2+ handling. We found that Liraglutide (100nM LIRA), a GLP-1 analog, increased mouse β-cell Ca2+ oscillation frequency and cAMP levels in high (11 mM) but not low glucose. Similarly, a subset of human β-cells (65%) show LIRA-induced elevations in Ca2+ oscillation frequency (by 70%, P<0.001) under stimulatory glucose (7 mM) conditions. While mouse islet HCN inhibition (20 μM ivabradine) did not alter glucose-stimulated (9 mM) Ca2+ oscillation frequency, it prevented LIRA-induced changes of islet Ca2+ fluctuations. As LIRA is used to treat type-2-diabetes, we examined and demonstrated that islets from high fat diet-fed, glucose intolerant mice also responded to LIRA with increased Ca2+ oscillation frequency (by 93%, P<0.01). These changes in β-cell Ca2+ handling may contribute to LIRA-mediated increased insulin secretion, which could also play a role in LIRA inhibition of glucagon secretion. However, as somatostatin also inhibits glucagon secretion, we next investigated the influence of LIRA on 𝛿;-cells. Interestingly, LIRA increased Ca2+ oscillation frequency equivalently in β- and 𝛿;-cells (by 85%, P<0.0001), which showed synchronized Ca2+ fluctuations. To establish the origin of synchronization cues, we ablated either β- or δ-cells and determined the LIRA-mediated effect on Ca2+ handling in remaining δ- or β-cells, respectively. Although δ-cell ablation did not affect the LIRA-mediated elevations in β-cell Ca2+ oscillation frequency, β-cell ablation interfered with glucose- and LIRA-mediated δ-cell Ca2+ fluctuations. As the kinetics of pulsatile insulin secretion dictate insulin sensitivity, the data presented here suggests that GLP-1 stimulation of islet HCN channels may improve peripheral insulin sensitivity in diabetics treated with LIRA.

Disclosure

K. E. Zaborska: None. K. L. Jordan: None. P. Dadi: None. M. Dickerson: None. S. M. Graff: None. D. Jacobson: None.
229-LB: Quantification of GLP-1R Internalization and Recycling in Live ß Cells
Authors: GRAY SARAH M. , SLOOP KYLE , RAVN PETER , CAMPBELL JONATHAN , D’ALESSIO DAVID A.
Published: June 2021

The glucagon-like peptide 1 receptor (GLP-1R) is a class B G-protein coupled receptor that is predominantly expressed on pancreatic β-cells in mice. Endogenous and synthetic ligands for GLP-1R exhibit distinct intracellular signaling cascades and promote insulin secretion to various degrees. Ligand binding typically induces receptor internalization followed by recycling back to the membrane or degradation within the lysosome. We hypothesized that endogenous and synthetic GLP-1R ligands would have distinct rates of internalization and recycling in β-cells. To test this hypothesis, we combined a recently-validated, highly-specific GLP-1R antibody (Glp1r0017) with flow cytometry and applied ligands (GLP-1, exendin-4 [Ex4], glucagon, and tirzepatide [TZP]) to characterize GLP-1R trafficking in freshly-isolated mouse islet cells. Under basal conditions, ~90% of β-cells were GLP1R+, with very low or absent binding in α- and δ-cells. Increasing ligand concentrations (0.01-100 nM) demonstrated distinct rates of internalization between ligands. Most potent was Ex4, followed by the native ligand GLP-1. TZP, a dual-receptor ligand for GLP-1R and GIPR, was more modest in inducing internalization. While showing different potencies, Ex4, GLP-1, and TZP were able to induce maximal internalization. In contrast, maximal treatment with glucagon only resulted in ~70% of β-cells being GLP-1R+. To test the rate of recycling back to the plasma membrane, we treated islet cells with Ex4 or GLP-1 with a dose that induced ~50% internalization, removed the ligand, and then monitored GLP1R+ β-cells over time. Within the first 15 minutes, GLP1R+ β-cells increased linearly and rapidly. This plateaued from 30-60 minutes, resulting in 60-70% of β-cells being GLP1R+ at the end of the experiment. In summary, our assay allows for investigation of GLP-1R trafficking in live β-cells. Understanding into the factors that regulate GLP-1R internalization and recycling may shed light on the insulinotropic properties of these ligands.

Disclosure

S. M. Gray: None. K. Sloop: Employee; Self; Eli Lilly and Company. P. Ravn: None. J. Campbell: None. D. A. D’alessio: Advisory Panel; Self; Eli Lilly and Company, Sun Pharmaceutical Industries Ltd., Research Support; Self; Eli Lilly and Company, Merck & Co., Inc.

Funding

National Institutes of Health (F32DK121420, R01DK123075, R01DK101991); Lilly Research Award Program
229-OR: Physical Fitness and Cardiovascular Risk Factors in Diabetes Subgroups
Authors: SAATMANN NINA , ZAHARIA OANA P. , STRASSBURGER KLAUS , PESTA DOMINIK , BURKART VOLKER , SZENDROEDI JULIA , RODEN MICHAEL
Published: June 2021

Physical inactivity promotes insulin resistance and increases the risk of diabetes and cardiovascular disease. Clustering based on simple clinical measures has been introduced for identifying diabetes subgroups with different risk of complications. However, little is known about physical fitness and cardiovascular risk factors in these clusters. We hypothesized that the insulin resistant diabetes (SIRD) cluster would associate with lower physical fitness and increased cardiovascular risk factors. Cycling spiroerogometry, physical activity questionnaire (Baecke index) and cardiovascular risk scores (Framingham Risk Scores (FRS) and triglycerides to high-density lipoproteins (TG:HDL) ratio) were analyzed in 746 participants with newly diagnosed diabetes of the German Diabetes Study (GDS). SIRD showed lower VO2max compared to the severe autoimmune diabetes (SAID), moderate age-related (MARD) and moderate obesity-related (MOD) clusters (all p<0.01) but was not different to the severe insulin deficient (SIDD) cluster (p= 0.87). Further, Baecke index was lower in SIRD [7.3 (6.8-8.4)] than SAID [8.5 (7.6-9.5)] and MARD [8.4 (7.3-9.4)] and SIRD had the highest TG:HDL ratio compared to all other groups (p<0.05) after adjustments for age, sex and BMI. This was underlined by a strong association between estimates of insulin resistance (HOMA-IR) and TG:HDL ratio (r= 0.59 p= <.0001) across all groups. Finally, SIRD showed higher FRS [33.1 (25.3-54.9)%] compared to MOD [16.2 (7.4-24.4)%], SAID [3.9 (1.6-9.4)%] and SIDD [12.4 (4.7-34.9)%].

In conclusion, SIRD and MARD showed lowest physical fitness and SIRD was least physically active and has the highest risk scores for diabetes-related cardiovascular diseases.

Disclosure

N. Saatmann: None. O. P. Zaharia: None. K. Strassburger: None. D. Pesta: None. V. Burkart: None. J. Szendroedi: None. M. Roden: Advisory Panel; Self; Allergan plc, Bristol-Myers Squibb Company, Novo Nordisk A/S, Research Support; Self; Boehringer Ingelheim International GmbH, Danone Nutricia, Sanofi-Aventis Deutschland GmbH.
230-OR: Exercise Training Improved Antilipolytic Sensitivity to Insulin in Obese Adults with Low Sensitivity to Insulin before Training
Authors: AHN CHEEHOON , SCHLEH MICHAEL W. , RYAN BENJAMIN J. , LUDZKI ALISON , VARSHNEY PALLAVI , GILLEN JENNA B. , CHEN SHIQI , HOROWITZ JEFFREY F.
Published: June 2021

Low sensitivity to the antilipolytic effects of insulin in adipose tissue has been linked with impaired insulin-mediated glucose uptake in skeletal muscle. The aims of this study were: 1) to compare adipose tissue morphology in obese adults with high- (HIGH) vs. low-sensitivity (LOW) to the antilipolytic effects of insulin, and 2) compare the effects of exercise training on adipose tissue from HIGH vs. LOW subjects. Using isotopic dilution methods before and during a hyperinsulinemic-euglycemic clamp, we measured the antilipolytic response to insulin in a total of 36 obese adults - and we identified sub-cohorts of 13 LOW (64±7% lipolytic suppression by insulin; BMI: 34±4kg/m2) and 13 HIGH (82±3% lipolytic suppression by insulin; BMI:33±3kg/m2). Abdominal subcutaneous adipose tissue (aSAT) samples were collected before the clamp (non-insulin stimulated). Measurements were made before and after a 12-week endurance exercise training program (4 days/week). Before training, capillary density (# of capillaries/mm2) in aSAT samples for LOW was significantly lower than HIGH (p=0.004). Collagen abundance in aSAT extracellular matrix (ECM) was lower in LOW (p=0.013). In response to training, the antilipolytic response to insulin was significantly improved in LOW (72±5% lipolytic suppression by insulin; p<0.001) but not HIGH. This was accompanied by an increased capillary density (p=0.03), and collagen abundance in ECM (p = 0.02), along with a slight reduction in fat mass (1±1kg; p=0.05). Adipocyte size was reduced in both groups (p=0.02).

In summary, aSAT from obese adults with low antilipolytic sensitivity to insulin displayed lower capillarization and ECM collagen abundance compared with obese adults with high sensitivity to the antilipolytic effects of insulin. Importantly, morphological adaptations to exercise training accompanied an increased antilipolytic sensitivity to insulin in subjects with low antilipolytic sensitivity before training.

Disclosure

C. Ahn: None. M. W. Schleh: None. B. J. Ryan: None. A. Ludzki: None. P. Varshney: None. J. B. Gillen: None. S. Chen: None. J. F. Horowitz: None.

Funding

National Institutes of Health (R01DK077966, P30DK089503, T32DK007245, F32DK117522); Canadian Institutes of Health Research (DFS146190, 338735)
233-OR: Circulating Inflammatory Biomarkers Are Not Improved with Combined Low-Volume High-Intensity Interval Training and Progressive Resistance Training in Prediabetes
Authors: BAKER CALLUM J. , MIN DANQING , GEROFI JAMES , WANG XIAOYU , HOCKING SAMANTHA L. , COLAGIURI STEPHEN , JOHNSON NATHAN A. , TWIGG STEPHEN M.
Published: June 2021

In prediabetes (PD), circulating inflammatory biomarkers are associated with increased CVD1 risk. Exercise (Ex) has a positive effect on cardiovascular fitness and metabolic outcomes in PD but Ex effects on inflammation markers in PD are not fully known and were investigated in this study. Adults with PD (n=34) and normal fasting glucose (NG) (n=34) were randomised into one of four groups: NG control (NGC, n=16), NG Ex (NGE, n=18), PD control (PC, n=16) and PD Ex (PE, n=18). NGE/PE completed 12 weeks of supervised HIIT and progressive resistance training (PRT) 2 times/week, and NGC/PC unsupervised stretching 3 times/week. Baseline, age and weight were similar in PD and NG. Compared with NG, FPG and HbA1c were higher and VO2peak was significantly lower in PD (29±7 vs. 33±8 mL/kg/min, p=0.03). Comparing NG and PD at baseline, serum IL-1β was higher in NG (11.4±9.0 vs. 7.9±2.8 pg/mL, p=0.04), IL-12p70 and IL-22 were higher in PD (respectively, 5.7±3.6 vs. 4.4±2.2 pg/mL; 164.6±90.3 vs. 122.2±83.2 pg/mL, both p<0.05) and IL-1α, IL-6, IL-8, IL-15, M-CSF and TNFα were similar. At follow-up, HbA1c was reduced by -0.07±0.11% in NGE and -0.09±0.17% in PC (both p<0.05) and not changed in PE or NGC. PE had an increase in VO2peak (5.5±7.5mL/kg/min, p=0.01). Inflammatory biomarkers were unchanged in PE but NGE had reduced IL-12p70 (4.3±1.9 to 3.5±0.8 pg/mL, p=0.05) and M-CSF (124.5±58.2 to 93.8±36.2 pg/mL, p=0.02). Analysis of Ex with >80% adherence revealed that IL-1α, IL-1β, IL-8 and IL-15 were reduced in NGE, however no change was seen in PE despite a reduction in HbA1c of -0.14±0.17% (p=0.02). PD is associated with reduced cardiorespiratory fitness and increased IL-12p70 and IL-22. Ex reduced IL-12p70 and M-CSF in those with NG but not PD, even after stratifying by adherence and despite improvements in clinical markers. This study indicates low volume HIIT with PRT may not be adequate to reduce serum inflammatory biomarkers in prediabetes.

Disclosure

C. J. Baker: None. D. Min: None. J. Gerofi: None. X. Wang: None. S. L. Hocking: Advisory Panel; Self; Eli Lilly and Company, Inova, Novo Nordisk, Pfizer Inc. S. Colagiuri: None. N. A. Johnson: None. S. M. Twigg: Advisory Panel; Self; Abbott Diabetes, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Sanofi-Aventis, Consultant; Self; Aktivo Labs, Sanofi-Aventis, Research Support; Self; Abbott Diabetes, Speaker’s Bureau; Self; Abbott Diabetes, AstraZeneca.

Funding

National Health and Medical Research Council (APP1113612)
24-OR: Time-to-Event GWAS for Incident Cardiovascular Disease in Type 2 Diabetes Patients
Authors: KWAK SOO HEON , WU PEITAO , MEIGS JAMES B. ,   ON BEHALF OF THE CHARGE DIABETES WORKING GROUP
Published: June 2021

Patients with type 2 diabetes (T2D) are at two-fold increased risk of cardiovascular disease (CVD), which is the leading cause of T2D morbidity and mortality. Here, we conducted a time-to-event genome-wide association study (GWAS) to identify genetic variants associated with incident CVD among patients with T2D in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium. Incident CVD was defined based on a composite of myocardial infarction, stroke, and cardiovascular death that occurred at least one year after the diagnosis of T2D. In each participating prospective cohort, we performed GWAS using a Cox proportional hazard survival model adjusting for age, and sex to identify genetic variants associated with incident CVD, and cohort-level estimated effect sizes were combined using inverse variance weighted fixed effects meta-analysis. A total of 37,327 participants were included in the analyses (26,928 European ancestry and 10,399 non-European ancestry) which comprised 6,012 primary event cases. We identified three distinct genetic loci associated with incident CVD among individuals with T2D that reached the threshold for genome-wide significance: rs231964 (intronic variant in NOX3, hazard ratio [HR] 1.4, P=8.3x10-9), rs139753656 (intronic variant in DCC, HR 2.0, P=2.4x10-8), and rs77202398 (intronic variant in TNS3, HR 1.4, P=4.4x10-8). Among 204 known coronary artery disease risk loci, 27 were associated with incident CVD with P<0.05 and rs6842241 upstream of EDNRA was associated with increased risk of CVD after Bonferroni correction (HR 1.1, P=1.2x10-4). The data provide evidence of novel and known genomic regions associated with incident CVD among individuals with T2D that require validation but point to novel targets.

Disclosure

S. Kwak: None. P. Wu: None. J. B. Meigs: Consultant; Self; Quest Diagnostics. On behalf of the charge diabetes working group: n/a.

Funding

National Institutes of Health (1R01HL151855-01)
243-OR: Integrating Genetic Risk Score and Islet Autoantibody Characteristics in the Predictive Model for Type 1 Diabetes in the TrialNet Study
Authors: FERRAT LAURIC A. , STECK ANDREA , PARIKH HEMANG M. , YOU LU , ONENGUT-GUMUSCU SUNA , GOTTLIEB PETER , RICH STEPHEN S. , KRISCHER JEFFREY , ORAM RICHARD A. , REDONDO MARIA J.
Published: June 2021

Background: Type 1 diabetes (T1D) genetic risk score (GRS) and islet autoantibody (AAb) specificity and titers influence T1D risk; however, these factors collected at baseline in cross sectional studies have not been effectively incorporated in the current models for prediction of progression along pre-clinical stages of T1D. Our aim was to develop an updated model of T1D prediction for research and clinical practice.

Methods: AAb-positive relatives of individuals with T1D (n=1,233, 52% female, 88% European ancestry, age mean 15 yrs [SD 12.2]) from the TrialNet Pathway to Prevention were followed for a median of 3.1 years (IQR 1.1 -7.1). T1D developed in 498/1,233 (40.4%). T1D GRS, AAb number, AAb combination, AAb titer, age and sex were evaluated on the combined T1D prediction model, estimating its performance using 3-fold cross-validation (10x repeated).

Results: Machine learning (survival random forest) and traditional methods (Cox models, extended Cox model) performed equivalently as measured by 5 yr horizon time-dependent AUC ROC (respectively 0.74, 0.74, 0.72), on calibration by integrated Brier score (respectively 0.15, 0.15, 0.16), and by calibration plots. AAb combinations with specific variables predicted T1D. In multivariate analysis, T1D GRS was a significant predictor of T1D in individuals positive for GADA, IAA or both. For any autoantibody combination including IA2A, the IA2A titer was predictive while the T1D GRS was not. Variable importance analyses showed that T1D was predicted by IA2A titer level, followed by T1D GRS and combinations of specific AAbs.

Conclusion: We modeled individual estimates of T1D risk with T1D GRS, AAb characteristics, age, and sex. T1D prediction improved by adding T1D GRS and AAb characteristics to other variables, and was similar using machine learning or traditional models. T1D GRS was a significant predictor only in the absence of IA2A. In the presence of IA2A, IA2A titer was the most influential factor.

Disclosure

L. A. Ferrat: None. M. J. Redondo: Advisory Panel; Self; Provention Bio, Inc. A. Steck: None. H. M. Parikh: None. L. You: None. S. Onengut-gumuscu: None. P. Gottlieb: Advisory Panel; Self; Janssen Research & Development, LLC, Tolerion, Inc., Viacyte, Inc., Other Relationship; Self; ImmunoMolecular Therapeutics, Inc., Research Support; Self; Caladrius Biosciences, Inc., Immune Tolerance Network, Mercia Pharma Inc., National Institute of Diabetes and Digestive and Kidney Diseases, Precigen, Inc., Tolerion, Inc. S. S. Rich: None. J. Krischer: None. R. A. Oram: Consultant; Self; Janssen Research & Development, LLC.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (1R01DK121843-01); JDRF (3-SRA-2019-827-S-B)
245-OR: Comprehensive Genome-Wide Association Study (GWAS) Meta-analysis Using TOPMed Imputation in Latinos Identifies Rare Variation Associated with Type 2 Diabetes (T2D)
Authors: HUERTA ALICIA , COLE JOANNE B. , DORNBOS PETER , DICORPO DANIEL A. , LEONG AARON , FLOREZ JOSE C. , MERCADER JOSEP M. ,   CONSORTIUM SIGMA T2D,   BIOBANK MX,   BIOBANK MGB
Published: June 2021

The high prevalence of T2D among Latino individuals emphasizes the importance of studying both environmental and genetic factors that influence disease in this population. However, Latino is a recently admixed population with complex linkage disequilibrium patterns that impose methodological challenges, especially when using genotype imputation to test association with rare variation. The recent release of the multi-ethnic NHLBI Trans-Omics for Precision Medicine (TOPMed) reference panel, comprising more than 100,000 samples (~10% are Latinos), represents a unique opportunity to explore rare genetic variation in this population.

We performed the largest T2D GWAS meta-analysis in the Latino population imputed to the TOPMed panel. Our analysis includes 18,294 individuals (7,556 cases and 10,738 controls) with genotyping array and whole-exome sequencing data. We were able to impute 38M high-quality variants (rsq>0.8) with TOPMed (5M with minor allele frequency [MAF] 0.001-0.0005) compared to 16M with 1000G Phase 3 panel (1.6M with [MAF] 0.001-0.0005). This allowed us to replicate previously reported T2D-associated common variants, and to identify a novel genome-wide significant variant (MAF=0.016, OR=2.06, P=1.7×10-9) near ORC5, a gene implicated in familial hyperinsulinemic hypoglycemia 2. Two additional suggestive novel signals merit further research: a variant in ROR2 (MAF=0.066, OR=1.3, P=8.8×10-8) and a Latino specific variant in HDAC2 only identified with the use of TOPMed (MAF=0.013, OR=1.82, P=3.2×10-7) and associated with insulin secretion in individuals without diabetes in this study.

Our results demonstrate the utility of the TOPMed imputation for the identification of novel and population-specific rare variation associated with T2D in understudied populations, which could lead to the identification of novel therapeutic targets and the improvement of polygenic risk scores.

Disclosure

A. Huerta: None. Mgb biobank: n/a. J. B. Cole: None. P. Dornbos: None. D. A. Dicorpo: None. A. Leong: None. J. C. Florez: Consultant; Self; Goldfinch Bio, Inc., Other Relationship; Self; Novo Nordisk. J. M. Mercader: None. Sigma t2d consortium: n/a. Mx biobank: n/a.

Funding

American Diabetes Association (1-19-ICTS-068 to J.M.M.)
25-OR: Role for TBC1D30 in Secretion of Mature Insulin
Authors: PARSONS VICTORIA A. , VADLAMUDI SWAROOPARANI , MOXLEY ANNE H. , MOHLKE KAREN L.
Published: June 2021

Genome-wide association studies (GWAS) have identified loci associated with the processing and secretion of mature insulin. Increased proinsulin (PI) secretion due to incomplete processing of insulin precursors has been linked to pancreatic beta-cell stress. At one PI GWAS locus, rs150781447-T is associated with increased PI secretion in Finns (p=5.5X10-11) and causes an amino acid (AA) change (R279C) at a conserved position in exon 4 of TBC1D30, a putative Rab GTPase Activating Protein (GAP), while no GWAS proxy variants (r2>0.8, 1000G Finns) are located in transcribed or enhancer regions. We hypothesized that TBC1D30 is involved in PI processing and that missense variant rs150781447, predicted to be damaging, has a negative impact on gene function. We used genome editing to generate four sets of TBC1D30 mutants in 832/13-INS1 cells. Compared to mock-edited control cells, apparent loss-of-function in frame insertion-deletion cells (106% expression) secreted 2.1-fold more PI (p=0.0001), and heterozygous truncation knockout cells (44% expression) secreted 1.9-fold more PI (p=0.005). Cells heterozygous for rs150781447, generated by prime editing, secreted 1.2-fold more PI (p=0.89), suggesting that the heterozygous variant has subtle or no effect on gene function. Unexpectedly, when exon 4 (42 AA) was deleted in frame, the cells secreted 3.2-fold less PI (p=0.02), consistent with a gain-of-function effect and suggesting that exon 4, part of the conserved Rab GAP protein domain, has a critical function. Preliminary insulin secretion data, while variable, demonstrate trends similar to proinsulin secretion, consistent with a stronger effect of TBC1D30 on processing than secretion. Together, these data demonstrate TBC1D30 as the likely target of the nearby PI GWAS locus and suggest that Rab GAP TBC1D30 plays a critical role in the processing of mature insulin.

Disclosure

V. A. Parsons: None. S. Vadlamudi: None. A. H. Moxley: None. K. L. Mohlke: None.

Funding

National Institutes of Health (1T32GM135128-01)
260-OR: The L-Cell Clock Is Required for Circadian GLP-1 Secretion and Maintenance of Intestinal Homeostasis
Authors: MARTCHENKO SARAH E. , MARTCHENKO ALEXANDRE , BIANCOLIN ANDREW , BRUBAKER PATRICIA L.
Published: June 2021

Glucagon-like peptide-1 (GLP-1) is an incretin hormone released by the intestinal L cell in response to nutrient intake. Recent studies identified a circadian rhythm in GLP-1 secretion that is disrupted in whole-body Bmal1 KO mice. However, the extent to which the L cell clock regulates circadian GLP-1 secretion and overall diurnal metabolic and intestinal homeostasis is unknown. Gcg-creERT2/+;Bmal1flox/flox KO mice with a disrupted clock in L cells, alpha cells and some CNS cells were thus generated. M/F- and age-matched KO mice had normal body weight and 24hr food intake patterns vs. all genetic and chemical controls. Upon oral glucose gavage at the known peak and trough timepoints of GLP-1 release, KO animals lost the rhythmic GLP-1 secretory pattern in association with impaired secretion (p<0.001) at the peak timepoint. Interestingly, the reduced GLP-1 secretion did not translate to decreased insulin or hyperglycemia, perhaps due to decreased glucagon levels (p<0.05). However, L cell Bmal1 KO caused increases in colonic weight and interleukin-6 (p<0.05) and interferon gamma (p<0.05) expression, suggesting a pro-inflammatory state. In line with findings that altered intestinal epithelial cell function decreases the frequency of intraepithelial CD4+ T cells, KO animals had reduced proportions of these immune cells (p<0.05). Furthermore, 16S rRNA gene analysis revealed increased actinobacteria in the colon, consistent with data from GLP-1 receptor KO mice. KO mice also had decreased levels of cecal bile acids (p<0.05-0.001) and short-chain fatty acids (p<0.05) suggestive of a functional impairment in the KO microbiome. Finally, siRNA-mediated knockdown of Bmal1 in the murine GLUTag L cell line also resulted in impaired rhythmic GLP-1 secretion (p<0.001). Together, these data establish the L cell clock as an essential regulator of circadian GLP-1 secretion which is, then, critical to the maintenance of overall intestinal homeostasis.

Disclosure

S. E. Martchenko: None. A. Martchenko: None. A. Biancolin: None. P. L. Brubaker: None.

Funding

Canadian Institutes of Health Research (PJT-15308)
271-OR: ADA Presidents’ Select Abstract: MyD88 Signaling in Trophoblasts Is Necessary for Maternal High-Fat Diet-Associated Developmental Programming of Obesity
Authors: RUEBEL MEGHAN L. , THAKALI KESHARI M. , CHINTAPALLI SREE V. , SHANKAR KARTIK
Published: June 2021

Maternal obesity (OB) contributes to programming of offspring obesity. A causal role for placental inflammatory mechanisms in developmental programming remains to be established. We examined the role of the toll-like receptor (TLR) pathway in mediating maternal obesity associated programming by trophoblast deletion of the TLR adapter protein MyD88. We generated MyD88fl/fl:Cyp19 Cre+ (conditional-KO, MyD88-CKO) and MyD88fl/fl:Cyp19 Cre- (flox-control, f/f) mice. Beginning at 5 wk of age, female MyD88-CKO mice were fed ad libitum control (17% fat calories, TD95092) or high-fat diets (HFD, 45% fat calories, TD08811) for 12 wk and then bred with lean MyD88fl/fl:Cyp19 Cre-(flox-control) males (fed control diet). This breeding strategy generated 50% of placenta/offspring with the Myd88-CKO genotype and genetically matched f/f littermate controls. At weaning, offspring (n = 10-12 from distinct litters) were randomized to control or HFD for 16 wk. All offspring have normal TLR signaling, since Cyp19 activity is only present in the placenta. Deletion of placental MyD88 had no effect on offspring growth on control diet. Male f/f offspring from HFD-dams fed HFD showed greater weight gain relative to f/f offspring from control-fed dams fed HFD, indicating an effect of maternal HFD. However, this effect of maternal HFD was not present in MyD88-CKO offspring from HFD-dams fed HFD, revealing a pivotal role for placental TLR signaling in the maternal HFD programming of obesity. Transcriptomic analyses of sex-identified placenta at dpc 17.5 showed that HFD altered more genes in male placenta (864 vs. 580, ±1.5 fold, p<0.05) in a MyD88-dependent manner. Gene ontology analyses showed that alterations in genes related to inflammation, extracellular matrix, and mitochondrial function were absent in placenta lacking MyD88. These findings provide the first unequivocal evidence that placental changes due to maternal HFD are causally related to offspring obesity risk.

Disclosure

M. L. Ruebel: None. K. M. Thakali: None. S. V. Chintapalli: None. K. Shankar: None.

Funding

U.S. Department of Agriculture (ARS-CRIS 6026-51000-012-00-D)
275-OR: Maternal Vitamin D Levels during Pregnancy Is Associated with Childhood Telomere Length: Analysis from a Longitudinal Mother-Child Cohort
Authors: WONG KWUN KIU , CHENG FEIFEI , MAO DI , LIM CADMON K.P. , WANG RONALD , TAM CLAUDIA H. , JOGLEKAR MUGDHA A. , HARDIKAR ANANDWARDHAN A. , JENKINS ALICIA , METZGER BOYD E. , LOWE WILLIAM , TAM WING H. , MA RONALD C.
Published: June 2021

Leukocyte telomere length (LTL) is a biomarker of biological aging, and has been associated with metabolic diseases such as type 2 diabetes (T2DM). Insufficient maternal vitamin D (25(OH)D) has also been associated with increased disease risk for many diseases and adverse later life outcomes. The association between maternal and cord blood total 25(OH)D and LTL was examined in mother-child pairs from the HAPO Hong Kong Field Centre, including 815 offspring at age (mean±SD) 6.96 ± 0.44 years. LTL was measured using real-time polymerase chain reaction and serum 25(OH)D2, 25(OH)D3 and 3-epi-25(OH)D3 were measured in maternal blood (at gestation 24-32 weeks) and cord blood by liquid chromatography-mass spectrometry. Children LTL at follow-up was significantly shorter in boys compared to girls (p<0.001) at age 7. Childhood LTL was positively associated with insulin sensitivity according to the Matsuda index after sex and age adjustment (β±SE=0.038±0.017, p=0.022). Multiple linear regression was used to evaluate the relationship between 25(OH)D levels and LTL, with covariate adjustments for child age, sex, body mass index (BMI), systolic blood pressure (SBP), exercise, gestational age, mode of delivery, and maternal age, SBP, parity, smoking, current parental DM status and pre-pregnancy BMI. Childhood LTL positively correlated with total maternal 25(OH)D concentrations (β±SE=0.003±0.001, p=0.001), maternal D3 (β±SE=0.003±0.001, p=0.002) and maternal D3 epimer (β±SE=0.138±0.042, p<0.001), and similar associations were noted for cord D3 epimer (β±SE=0.101±0.045, p=0.024) and cord total 25(OH)D (β±SE=0.1±0.05, p=0.048), even after covariates adjustments. Our findings suggest 25(OH)D, D3 and D3 epimer both in utero and at birth may impact on childhood LTLs, highlighting a potential link between maternal vitamin D and biological aging.

Disclosure

K. Wong: None. B. E. Metzger: None. W. Lowe: None. W. H. Tam: None. R. C. Ma: Other Relationship; Self; AstraZeneca, Medtronic, Research Support; Self; AstraZeneca, Bayer Healthcare Pharmaceuticals Inc., Novo Nordisk, Pfizer Inc., Sanofi-Aventis, Tricida, Inc. F. Cheng: None. D. Mao: None. C. K. P. Lim: Stock/Shareholder; Self; GemVCare Ltd. R. Wang: None. C. H. Tam: None. M. A. Joglekar: None. A. A. Hardikar: None. A. Jenkins: Advisory Panel; Self; Abbott Diabetes, Sanofi-Aventis, Other Relationship; Self; Amgen Inc., Research Support; Self; Abbott, International Diabetes Federation, JDRF, Medtronic, Mylan N. V.