bluuebunny/crossref_metadata_2025_split huggingface dataset:
259-OR: The Effect of Impaired Glucagon Suppression on Endogenous Glucose Production Is Independent of Insulin Action
Authors: LAURENTI MARCELLO C. , EGAN AOIFE M. , WISMAYER DANIEL SCHEMBRI , COBELLI CLAUDIO , MAN CHIARA DALLA , VELLA ADRIAN 
Published: June 2021

Type 2 diabetes is a disease characterized by impaired insulin secretion and defective glucagon suppression in the postprandial period. We examined the effect of impaired glucagon suppression on glucose concentrations and Endogenous Glucose Production (EGP) at different degrees of insulin secretory impairment. The contribution of anthropometric characteristics, peripheral, and hepatic, insulin action to this variability was also examined. To do so, we studied 54 nondiabetic subjects on two occasions in which endogenous hormone secretion was inhibited by somatostatin, with glucagon infused at a rate of 0.65 ng/kg/min, at 0 min to prevent a fall in glucagon (non-suppressed day) or at 120 min to create a transient fall in glucagon (suppressed day). Subjects received glucose (labeled with [3-3H]-glucose) infused to mimic the systemic appearance of 50g oral glucose. Insulin was infused to mimic a prandial insulin response in 18 subjects, another 18 received 80% of the dose and the remaining 18 received 60%. EGP was measured using the tracer-dilution technique. Decreased prandial insulin resulted in greater % increase in peak glucose (56±5 vs. 44±6 vs. 31±6 %, p=0.01 - 0.6, 0.8 and 1.0 dose respectively) but not in integrated (area above basal - AAB) glucose (39±4 vs. 43±9 vs. 36±9 %, p=0.82) caused by non-suppressed glucagon. The % change in integrated EGP was unaffected by insulin dose (51±20 vs. 27±19 vs. 22±18 %, p=0.53). Multivariate regression analysis, adjusted for age, sex, weight and insulin dose, did not show a relationship (R2=0.04, p=0.21) between the EGP response to impaired suppression of glucagon and insulin action as measured at the time of screening by oral glucose tolerance. A similar analysis for hepatic insulin action did not show a relationship (R2=0.06, p=0.06) with the EGP response to non-suppressed glucagon. These data indicate that the change in EGP produced by impaired glucagon suppression is independent of anthropometric characteristics and insulin action.

Disclosure
M. C. Laurenti: None. A. M. Egan: None. D. Schembri wismayer: None. C. Cobelli: None. C. Dalla man: Research Support; Self; Becton, Dickinson and Company, Sanofi-Aventis Deutschland GmbH. A. Vella: Research Support; Self; Novo Nordisk.

Funding
National Institutes of Health (DK116231, DK78646)
261-OR: Transcriptional Profiling of the Intestinal Serotonin System in Individuals with Type 2 Diabetes and Healthy Individuals
Authors: LEGART CHRISTIAN , HAGEMANN CHRISTOFFER A. , ELLEGAARD ANNE MARIE , KEATING DAMIEN , JORSAL TINA , KNOP FILIP K. 
Published: June 2021

Obesity is characterized by increased gut serotonin signaling, which has been shown to enhance hepatic gluconeogenesis favoring hyperglycemia and adipose tissue lipolysis promoting raised levels of free fatty acids and, thus, peripheral insulin resistance. Little is known about the potential involvement of the human gut serotonin system in the pathophysiology of type 2 diabetes. We investigated the transcriptional profile of key enzymes, receptors and transporters in the serotonin system in intestinal biopsies sampled using double-balloon enteroscopy from the duodenum, the jejunum, throughout the remaining small intestine with 30 cm intervals, the ileocecal region, the cecum, the four segments of the colon and the rectum in 12 individuals with type 2 diabetes and 12 gender, age and body mass index-matched healthy controls. Global gene expression analysis was performed on all biopsies, and intestinal expression profiles of genes involved in the serotonin system were mapped and compared between the two groups. We used false discovery rate adjustment to correct for multiple testing. Patients with type 2 diabetes exhibited 2-fold increased mRNA encoding the serotonin-synthesizing enzyme TPH1 in the sigmoid colon (P = 0.027) and the rectum (P &lt; 0.001), and lower levels of mRNA encoding the transporter responsible for reuptake of serotonin in enterocytes, SERT (P = 0.038), and the serotonin-metabolizing enzymes MAOA (P = 0.001) in the distal small intestine and MAOB in the cecum (P = 0.013), the ascending colon (P = 0.020) and the transverse colon (P = 0.011). Our findings provide the first detailed transcriptional profile of key factors in the serotonin system along the entire intestinal tract in humans and lend support to previous animal and human studies suggesting that increased gut serotonin signaling may be involved in the development of dysmetabolic conditions including type 2 diabetes.

Disclosure
C. Legart: None. C. A. Hagemann: None. A. Ellegaard: None. D. Keating: None. T. Jorsal: None. F. K. Knop: Advisory Panel; Self; MSD Corporation, Novo Nordisk A/S, Sanofi, Consultant; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Novo Nordisk A/S, Pharmacosmos, Zealand Pharma A/S, Research Support; Self; Novo Nordisk A/S, Zealand Pharma A/S, Speaker’s Bureau; Self; AstraZeneca, Bayer AG, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, MSD Corporation, Novo Nordisk A/S.
272-OR: Impact of Maternal Diabetes on MicroRNA Expression in Fetal Tissue
Authors: RUGHANI ANKUR , TRYGGESTAD JEANIE B. 
Published: June 2021

In utero diabetes (DM) exposure alters offspring metabolic memory and increases future cardiovascular risk (CVD) risk. MicroRNAs (miR), small noncoding RNAs that repress mRNA translation, have been proposed as an epigenetic mechanism that alters metabolic programming. Using an unbiased sequencing approach, the impact of in utero DM exposure on miR abundance in human umbilical vein endothelial cells (HUVEC) from 6 DM-exposed infants and 6 infants born to mothers with normal glycemia matched for infant sex, ethnicity, and gestational age was examined. Computational target prediction algorithms were used to identify genes targeted by the most abundant miRNAs. The gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the most abundant miRNAs and their mRNA targets were annotated. MiRNA expression was quantified using RT-PCR. GO target enrichment analysis suggested the targets of the most abundant miRNAs were involved in transport, protein binding, mitochondria, DNA transcription, and cell cycle. The KEGG analysis found the most significantly enriched pathways were PI3K-Akt, AGE-RAGE signaling in diabetic complications, apoptosis, FoxO signaling, MAPK signaling, and cell senescence. In HUVEC from infants exposed to DM in utero, 31 miRNAs were more abundant including miR-210, miR-130b-3p, miR-491-5p while 6 miRs were less abundant including miR-146b-5p, mIR-192-3p, and miR-30e-5p (p&lt;0.05) compared to matched controls. Analysis with RT-PCR revealed a 25% decrease in miR-146b (p 0.03) from the HUVEC of DM-exposed infants (N = 23) compared to controls (N = 39). MiRNA-146b is an anti-inflammatory molecule that targets IRAK1 and TRAF6 both of which modulate the NF-kB inflammatory pathway and affect the progression of CVD. MiRNA-146b is reduced in hypercholesterolemia and is protective to cardiomyocytes under chronic hypoxia. Sortilin, a target of miR-146b, is also associated with CVD. Thus, miR-146b may play a role in the development of excess CVD risk noted after in utero DM exposure.

Disclosure
A. Rughani: None. J. B. Tryggestad: None.
278-OR: Ancestry-Specific Genetic Risk Scores of Type 2 Diabetes and Longitudinal Fetal Growth in a Race-Ethnic Diverse Population
Authors: OUIDIR MARION , ZENG XUEHUO , CHATTERJEE SUVO , ZHANG CUILIN , TEKOLA-AYELE FASIL 
Published: June 2021

It is well documented that maternal type 2 diabetes (T2D) is related to fetal overgrowth. Further, maternal T2D genetic risk score (GRS) has been associated with increased offspring birthweight. However, the earliest gestational age when fetal growth starts to be associated with T2D GRS is unknown. We investigated the associations between maternal T2D GRS and longitudinal ultrasound measured fetal weight.
We included 1,513 women of diverse race/ethnicity from the NICHD Fetal Growth Studies-singleton cohort. Women were enrolled at gestational weeks 8-13 and randomly assigned to four ultrasound schedules to capture weekly fetal growth. Genome-wide single nucleotide polymorphisms (SNPs) previously known to be associated with T2D in European-, African-, and Asian- ancestry populations (380, 104, and 19 SNPs, respectively) were used to calculate weighted GRS. The analysis involved European GRS for Whites and Hispanics, African GRS for Blacks and Asian GRS for Asians. Associations between quartiles of GRS and fetal weight were adjusted for pre-pregnancy BMI, population structure, fetal sex and gestational weeks.
Among Whites, the highest quartile of European GRS was related to a 53.8 g increment in fetal weight (95% CI 19.2-88.5 g) over the pregnancy, and across 24 to 40 weeks (from 15.8 g increase at week 24 to 196.0 g increase at week 40). Similar findings were observed in analysis that excluded women with impaired glucose tolerance. African-, European- and Asian-GRSs were not significantly associated with fetal weight among other race/ethnic groups.
Genetic susceptibility to T2D based on European-specific GRS among Whites was related to increased fetal weight starting at week 24 even among normal glycemia women, suggesting an early influence of genetic factors on fetal growth. Absence of similar associations in non-Whites is likely due to the small number of established T2D genetic loci warranting the need for genetic studies of T2D in diverse populations.

Disclosure
M. Ouidir: None. X. Zeng: None. S. Chatterjee: None. C. Zhang: None. F. Tekola-ayele: None.
287-OR: M6A mRNA Methylation Regulates the Innate Immune Response in Human ß-Cells
Authors: DE JESUS DARIO F. , ZHANG ZIJIE , BROWN NATALIE K. , HU JIANG , KAHRAMAN SEVIM , MATHEWS CLAYTON E. , POWERS ALVIN C. , ATKINSON MARK A. , EIZIRIK DECIO L. , HE CHUAN , KULKARNI ROHIT 
Published: June 2021

Type 1 diabetes (T1D) is an autoimmune disease characterized by a progressive destruction of β-cells and several candidate genes associated with T1D have been linked to innate immunity. Recently, N6-methyladenosine (m6A) has been shown to modulate human β-cell biology and to target type I interferons. Here, we focused on the contribution of m6A mRNA methylation in modulating innate immunity and β-cell destruction. Immune cells contribute to β-cell apoptosis by the release of pro-inflammatory cytokines during the onset of T1D. We assessed whether m6A abundance or expression of m6A modulators was altered in human islets and EndoC-βH1 cells treated with cytokines to mimick T1D onset. LC-MS/MS analyses of human islets showed that treatment with IL-1β plus IFN-α for 48h increased m6A levels. Consistently, IL-1β plus IFN-α treatment of human islets and EndoC-βH1 induced upregulation of the m6A writer METTL3. Next, we applied m6A-sequencing in cytokine-treated human islet preparations, and in parallel studies, treated EndoC-βH1 cells followed by RNA-sequencing. Intersection of m6A-decorated genes in cytokine-treated human islets with common differentially expressed genes in human islets and EndoC-βH1 cells revealed enrichment in pathways associated with the innate immune response, negative regulation of immune response, and extrinsic apoptotic signaling pathway. Differentially expressed and m6A decorated genes included genes associated with T1D that are involved in innate immunity. Re-analyses of RNA-seq. data in sorted-β-cells from T1D patients revealed downregulation of METTL3. These data suggest that while healthy β-cells are able to upregulate m6A levels and METTL3 early in T1D (e.g., when they are exposed to cytokines), this response is lost in established T1D that allows an exacerbated immune response and β-cell death. Together, these results point to a possible therapeutic approach in targeting METTL3 to modulate innate immunity and promote β-cell survival.

Disclosure
D. F. De jesus: None. C. He: None. R. Kulkarni: None. Z. Zhang: None. N. K. Brown: None. J. Hu: None. S. Kahraman: None. C. E. Mathews: None. A. C. Powers: None. M. A. Atkinson: None. D. L. Eizirik: None.

Funding
National Institutes of Health (1UC4DK116278)
294-OR: RIPK3-Mediated Necroptosis Is an Alternative Form of TNFa-Induced ß-Cell Death
Authors: CONTRERAS CHRISTOPHER J. , LIN LI , HOGAN MEGHAN F. , OBERST ANDREW , KAHN STEVEN E. , TEMPLIN ANDREW T. 
Published: June 2021

Necroptosis is an inflammatory and immunogenic form of lytic cell death that can occur downstream of TNFα signaling. Receptor interacting protein kinase 3 (RIPK3) mediates TNFα-induced necroptosis when caspase activity is repressed, but this pathway has not been examined in insulin-producing β-cells. As TNFα contributes to β-cell death in the setting of diabetes and since we found RIPK3 is expressed in INS-1 β-cells and mouse islets, we hypothesized that β-cells are susceptible to necroptosis. To test this hypothesis, INS-1 cells were treated with TNFα (40 ng/ml) in the absence or presence of a synthetic pan-caspase inhibitor (zVAD, 50 μM) for 24 h, cell death was monitored in real-time, and caspase activity was determined. TNFα increased INS-1 cell death (1.63 ± 0.13 vs. 2.44 ± 0.13 fold, n=7, p&lt;0.001) and caspase activity, consistent with apoptosis. When caspases were inhibited with zVAD, TNFα no longer increased caspase activity, but induced a similar degree of cell death (1.63 ± .013 vs. 2.82 ± 0.23 fold, n=7, p&lt;0.001), suggesting an alternate mechanism under these conditions. Moreover, when TNFα-induced cell death was amplified by the SMAC/DIABLO mimetic BV6 (5 μM), we again observed similar levels of cell death with or without zVAD. To further investigate the mechanism of cell death under caspase inhibition, we used the RIPK3 inhibitor GSK ‘872 (5 μM). GSK ‘872 had no effect on TNFα+BV6-induced cell death when caspases were activated (3.35 ± 0.61 vs. 3.48 ± 1.21 fold, n=3, p=0.93), but reduced cell death when caspases were inhibited (4.69 ± 0.57 vs. 1.81 ± 0.57 fold, n=3, p=0.04). These data indicate that TNFα induces β-cell death independent of caspase activity level. However, the mechanism by which TNFα elicits β-cell death does depend on caspase activity, with apoptosis occurring when caspases are activated, and RIPK3-mediated necroptosis occurring when caspases are inhibited. Additional studies are required to understand the factors that may promote β-cell necroptosis in the setting of human diabetes.

Disclosure
C. J. Contreras: None. L. Lin: None. M. F. Hogan: None. A. Oberst: None. S. E. Kahn: Advisory Panel; Self; Bayer AG, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Merck & Co., Inc., Novo Nordisk, Pfizer Inc. A. T. Templin: None.

Funding
U.S. Department of Veterans Affairs (IK2BX004659, I01BX001060)
299-OR: Relative Contribution of Statin Intensity, Low-Density Lipoprotein Cholesterol Level and Duration of Statin Therapy for Cardiovascular Risk Reduction in Patients with Type 2 Diabetes
Authors: KIM JI YOON , CHOI JIMI , KIM SIN GON , KIM NAM HOON 
Published: June 2021

Objectives: To estimate the optimal statin therapy including statin intensity, low-density lipoprotein cholesterol (LDL-C) level and duration of statin therapy among patients with type 2 diabetes (T2D) in a real-world setting.
Research Design and Methods: From the Korean National Health Insurance Service Cohort (2007-2015), 8,937 patients with T2D (≥40 years) who had received statin therapy for at least 90 days were included. Risk of major adverse cardiovascular events (MACE) including coronary heart disease (CHD), ischemic stroke (IS) and cardiovascular death was estimated according to statin intensity, on-treatment serum concentration of LDL-C and duration of statin therapy, respectively. The relative contribution of these three factors for the risk of MACE was quantified by calculating the proportion of log-likelihood explained by each factor.
Results: The hazard ratio (HR) of MACE was higher in patients receiving low intensity statins compared with those receiving moderate-to-high intensity statins (HR 1.38, p=0.027). As a reference to LDL-C of 100 mg/dl, below 80 mg/dl was associated with lower risk of MACE. Among patients who received moderate-to-high intensity statins, there was a trend that the longer the duration of statin therapy, the lower the risk of MACE; and HRs of MACE reduced significantly after at least 18 months of statin therapy (adjusted HR 0.71, p=0.011) as a reference to 3 months of statin therapy. The proportion of explainable log-likelihood for MACE was biggest for duration of statin (0.047), followed by statin intensity (0.013) and on-treatment LDL-C level (0.001).
Conclusion: Longevity of statin therapy is as important as, or more important than, statin intensity or achieved LDL-C for the reduction of cardiovascular risk in T2D patients.

Disclosure
J. Kim: None. J. Choi: None. S. Kim: None. N. Kim: None.
3-LB: Glutamate Metabolism Is Coupled to Lactate Production from Astrocytes under Low-Glucose Conditions
Authors: APPADURAI DANIEL A. , CHAN OWEN 
Published: June 2021

Recurrent hypoglycemia (RH) results in elevated lactate levels in the ventromedial hypothalamus that impair the counter-regulatory responses to hypoglycemia. While the mechanisms that enhance lactate production are not clear, our previous data suggests that astrocytic glycogen is the major source of lactate resulting from RH. A number of different inputs regulate glycogen turnover in astrocytes and the interaction between metabolic and neurotransmitter signals may alter glycogenolytic capacity and ultimately, lactate production. The current study investigates how the interaction between norepinephrine and glutamate influence lactate production from astrocytes in the setting of hypoglycemia. We cultured primary rat astrocytes in normal (2.5mM) and low (0.1mM) glucose medium in the presence and absence of norepinephrine and/or glutamate for 3 hours and quantified lactate in the culture media. We also examined the contribution of glutamate oxidation using the glutamate dehydrogenase inhibitor, hexachlorophene. Our data indicates that under low glucose conditions, glutamate alone dramatically enhances lactate production in astrocytes compared to controls (P&lt;0.0001). Of note, the inhibition of glutamate oxidation also increased lactate secretion, but not to the same extent as glutamate alone (P&lt;0.01). In contrast, the addition of norepinephrine and glutamate significantly reduced lactate secretion (P&lt;0.05). Our data suggests that glutamate uptake during acute hypoglycemia likely plays a large role in driving astrocytic lactate production, a metabolic deficit that is offset by the oxidation of glutamate and by norepinephrine. In conclusion, our data suggests that under low glucose conditions, the metabolism of glutamate is tightly coupled to lactate production in astrocytes.

Disclosure
D. A. Appadurai: None. O. Chan: None.

Funding
National Institutes of Health (DK099315)
310-OR: Five-Year Trends in American Diabetes Association Recommended Metabolic Screening for Youth Prescribed Antipsychotic Medications
Authors: HSUEH LORETTA , SLAMA NATALIE , SPALDING SCOTT , STERLING STACY , ITURRALDE ESTI 
Published: June 2021

Importance: In recent decades, youth have increasingly been prescribed antipsychotic medications to treat a range of mental health conditions. These medications are associated with metabolic disturbances elevating type 2 diabetes risk, but ADA-recommended metabolic screening rates have stagnated at low levels (&lt;50%) for youth treated with antipsychotics. We examined 5-year metabolic screening trends and predictors for this population in a large, integrated health system.
Methods: In this serial cross-sectional study, we assessed metabolic screening (fasting glucose or hemoglobin A1c test) from health record data for 4,541 youth age 10-21 starting antipsychotic treatment in Kaiser Permanente Northern California during 2013-2017. We evaluated time and demographic predictors of metabolic screening within 2 years of medication start using logistic regression. To understand screening trends by age, sex, and racial groups, we estimated additional models with time x group interaction terms.
Results: Participants were mean ± SD age 16.9 ± 3.0; 52% were boys. Half were racial minorities (22% Hispanic/Latino; 13% Black; 12% Asian/Nat. Hawaiian/Pac. Islander [ANHPI]). Screening significantly increased over the 5 cohort years (adj. rates rising from 54% to 64%). Younger participants, girls, and ANHPI and Hispanic/Latino participants had higher screening rates overall (all p&lt;0.05); time trends did not differ by age, sex, or race.
Conclusions and Relevance: In this large health system, which has established processes to promote preventive care (e.g., automatic patient reminders), metabolic screening has increased for youth treated with antipsychotics and exceeds those reported in other samples. Future research should examine processes contributing to this upward trend and identify remaining barriers to achieving ADA-recommended metabolic screening rates for this vulnerable population.

Disclosure
L. Hsueh: None. N. Slama: None. S. Spalding: None. S. Sterling: None. E. Iturralde: None.

Funding
Permanente Medical Group