bluuebunny/crossref_metadata_2025 huggingface dataset:
187-OR: Declines in ß-Cell Glucose Responsiveness Correlate with Loss of Glucose Metabolism during T1D Pathogenesis
Authors: HUBER MOLLIE , RUPNIK MARJAN SLAK , DROTAR DENISE M. , HILLER HELMUT , BEERY SR., MARIA , KUSMARTSEVA IRINA , ATKINSON MARK A. , PHELPS EDWARD , MATHEWS CLAYTON E.
Published: May 2022

Features of type 1 diabetes (T1D) include loss of first-phase insulin secretion in response to glucose, declining c-peptide, and glucose intolerance; indicating β cell dysfunction. Here, we investigate the mechanisms of this dysfunction with the hypothesis that immune dysregulation during the early stages of T1D development impacts β cell dysfunction in pathways affecting glucose metabolism. The live pancreas tissue slice (LPTS) model is ideal for the study of T1D pathogenesis due to its preservation of the pancreatic environment. LPTS were generated from organ donors without diabetes or autoantibodies (ND, n=9) , donors positive for one or more autoantibodies without a diagnosis of T1D (AAb+, n=6) , and donors with T1D (T1D, n=4) . Imaging studies were conducted to assess the impact of T cell infiltration on β cell function through Ca2+ imaging and slice perifusion. Islets from ND and AAb+ donors had no insulitis and exhibited Ca2+ responses to both high glucose (HG) and potassium chloride (KCl) . A majority of β cell+ islets in tissue from donors with T1D had infiltrating T cells with several having insulitis. Islet HG response from donors with T1D was heterogenous (∼50% failed to respond) while all T1D islets exhibited responses to KCl. Insulin secretion was significantly higher in LPTS from ND donors than in donors with T1D (p=0.0079) . To determine the basis for this loss of function, we assessed transcriptomics of islets within these cohorts. When comparing gene expression levels in islets from ND versus T1D, significant differences were observed in genes involved in glycolysis (GAPDH, p=3.27x10-21) , the citric acid cycle components (OGDH, p=1.88x10-18) , and the electric transport chain (F1FoATP synthase, p=2.69x10-13) . The decreased expression of glucose metabolism genes during T1D development along with the loss of β cell function in LPTS demonstrates β cell dysfunction before their demise and may be a contributory mechanism towards the pathogenesis of disease.

Disclosure

M.Huber: None. M.Slak rupnik: None. D.M.Drotar: None. H.Hiller: None. M.Beery: None. I.Kusmartseva: None. M.A.Atkinson: None. E.Phelps: Research Support; Immunocore, Ltd. C.E.Mathews: None.

Funding

National Institutes of Health (5T32DK108736-03) National Institutes of Health (PO1 AI42288)
190-LB: Vaspin—A Novel Predictor of Type 2 Diabetes Risk
Authors: WANG HARRY , CHONG MICHAEL , PERROT NICOLAS , FEINER JAMES , HESS SIBYLLE , YUSUF SALIM , GERSTEIN HERTZEL C. , PARE GUILLAUME , PIGEYRE MARIE
Published: May 2022

Vaspin (visceral adipose tissue-derived serpinA12) is an adipokine suspected to be involved in type 2 diabetes (T2D) pathogenesis, linking obesity and T2D. We sought to assess epidemiological and genetic associations of vaspin with T2D and related variables.

We assessed the relationship of body-mass index (BMI) and waist-hip ratio (WHR) and plasma vaspin concentration, along with the relationship between plasma vaspin and adiposity-related variables and T2D in (i) a case-cohort within the Prospective Urban and Rural Epidemiology (PURE) prospective multi-country study (N=10,052) , and (ii) the Outcome Reduction with Initial Glargine Intervention (ORIGIN) Trial (N=7,840) of participants with dysglycemia. We next investigated the predictive value of vaspin for T2D risk. All models adjusted for age, sex, and ethnicity. Using two-sample Mendelian randomization (MR) , we analyzed if genetically higher vaspin is causal for T2D. The MR analysis used 34 independent genetic variants (linkage disequilibrium r2<0.1) associated with vaspin concentration in PURE (N=3,513) , estimating their effect on BMI-adjusted T2D risk in the DIAGRAM (DIAbetes Genetics Replication And Meta-analysis) consortium (N=898,130) .

In PURE, a 1 unit increase in BMI and WHR was associated with a 0.01 SD (95% CI 0.01 - 0.02; P = 2.04x10−15) and 0.45 SD (95% CI, 0.21 - 0.70; P = 2.87 × 10−4) increase in plasma vaspin respectively. A 1 SD increase in plasma vaspin was associated with higher triglycerides (0.09 mmol/L; 95% CI, 0.07 - 0.12, P = 4.08x10−13) . Directionally-consistent associations were observed in ORIGIN. A 1 SD increase in plasma vaspin was associated with a 19% increase in incident T2D risk in PURE (HR, 1.19; 95% CI, 1.12 - 1.26; P = 6.36x10−8) and a 16% increase in prevalent T2D in ORIGIN (OR, 1.16; 95% CI, 1.07 - 1.25; P = 2.17x10−4) . Sensitivity analyses showed vaspin's specificity for T2D. Genetically-higher vaspin was associated with increased BMI-adjusted T2D risk (OR, 1.02; 95% CI, 1.00 - 1.03; P = 5.46x10−3) .

Our data suggests that vaspin is a predictor for T2D risk, a modest causal factor for T2D development, and might represent a potential T2D therapeutic target.

Disclosure

H. Wang: None. M. Chong: None. N. Perrot: None. J. Feiner: None. S. Hess: Employee; Sanofi. S. Yusuf: None. H. C. Gerstein: Advisory Panel; Abbott, Eli Lilly and Company, Hanmi Pharm. Co., Ltd., Novo Nordisk, Pfizer Inc., Sanofi, Viatris Inc., Consultant; Kowa Company, Ltd., Other Relationship; DKSH, Eli Lilly and Company, Sanofi, Zuellig Pharma Holdings Pte. Ltd., Research Support; AstraZeneca, Eli Lilly and Company, Merck & Co., Inc., Novo Nordisk, Sanofi. G. Pare: Advisory Panel; Amgen Inc., Bayer AG, Sanofi, Research Support; Bayer AG. M. Pigeyre: n/a.

Funding

PURE biomarker study was sponsored by Bayer and CIHR. Origin (NCT00069784) and the biomarker-substudy in Origin were sponsored by Sanofi and CIHR.
192-LB: Ductal Epithelial Cells Adopt Transcriptional Features of Tolerogenic Dendritic Cells in Type 1 Diabetes
Authors: KAESTNER KLAUS H. , CONSORTIUM HPAP , VAHEDI GOLNAZ
Published: May 2022

Type 1 diabetes (T1D) is an autoimmune disease in which immune cells destroy insulin-producing beta cells. Disease etiology is dependent on the interplay of multiple heterogeneous cell types in the pancreatic environment; however, technical constraints have thus far impeded our understanding of the initial molecular perturbations that occur during disease progression and a comprehensive identification of the pathogenic cell types in T1D. In particular, it is difficulty to safely biopsy the human pancreas of living donors, and there is significant disease progression and beta cell destruction by the time patients are clinically diagnosed with T1D. To address this, the Human Pancreas Analysis Program (HPAP) collects pancreatic tissues from deceased organ donors diagnosed with T1D and performs comprehensive molecular phenotyping. Using the full spectrum of imaging, genetic, and genomic technologies available through HPAP, we discovered that a subset of pancreatic ductal cells acquires the signature of tolerogenic dendritic cells in an apparent attempt at immune suppression in T1D donors. Single cell RNA-seq revealed a highly significant enrichment of the tolerogenic dendritic cell gene signature in ductal cells of T1D donors, including activation of interferon genes. In addition, via highly multiplexed flow CyTOF, we identified a population of ductal cells expressing dendritic cell proteins that was enriched in pancreata from T1D donors. Finally, we confirmed these results independent of islet culture via analysis of spatial features in pancreatic tissue using imaging mass cytometry. Together, our multi-modal analyses, ranging from transcriptomics to spatial proteomics, suggest that in the setting of disease, ductal cells are transcriptionally similar to tolerogenic ductal cells These results imply a previously unappreciated role of these exocrine cells in modulating immune cell activity in long-term T1D.

Disclosure

K. H. Kaestner: None. Hpap consortium: n/a. G. Vahedi: None.

Funding

NIH UC4 DK112217NIH R01CA230800Susan G. Komen CCR185472448 NIH R01HL145754NIH U01DK127768The Burroughs Wellcome FundThe Chan Zuckerberg Initiative, Penn EpigeneticsThe Sloan Foundation
193-LB: Differentiation of PTPN2 Knockout Pluripotent Stem Cells into Stem-Cell–Derived ß-Like Cells Leads to Increased Stimulation of Diabetogenic TCR T Cell Transductants
Authors: MATUSCHEK JULIA Q. , RUSS HOLGER A. , TRIOLO TAYLOR M. , MICHELS AARON W. , MCDANIEL KRISTEN , HANSEN MARIA S. , WILLIAMS SHANE , CASTRO-GUTIERREZ ROBERTO , SHILLEH ALI
Published: May 2022

Type 1 diabetes (T1D) is an autoimmune disease marked by permanent loss of insulin-producing pancreatic β cells. Genome wide association studies have identified protein tyrosine non receptor type 2 (PTPN2) as a high-risk T1D gene. PTPN2 has been classically implicated in immune cell function, but is expressed in T cells, B cells, and in pancreatic β cells. Mice with a β cell specific knock out (KO) of ptpn2 exhibit impaired function and increased susceptibility to stress induced β cell death. We hypothesized that altered PTPN2 expression in pancreatic beta cells may contribute to T1D disease development. In order to study PTPN2 in the human context we generated CRISPR/Cas9 mediated clonal PTPN2 knock out (KO) hPSCs, abolishing the functional domain of PTPN2. PTPN2 KO and WT hPSCs were differentiated into functional stem cell derived beta-like cells (sBCs) using our published protocol without significant differences in key developmental markers or insulin content. Compared to WT sBC, PTPN2 KO sBCs at steady state and under T1D stress conditions show increased expression of HLA Class I molecules important in T cell recognition. To investigate the interaction of KO or WT sBCs with diabetogenic T cells we employed an HLA-peptide-TCR matched coculture system we recently established. Using this system, we observed increased stimulation of diabetogenic TCR T cell transductants by KO sBC compared to WT. Our data provide evidence for a potential mechanism by which PTPN2, a known T1D high-risk gene may contribute to an immunogenic phenotype of β cells. Our findings suggest that dysregulation of PTPN2 expression contributes to an autoimmune response towards human β cells thus contributing to the pathogenesis of type 1 diabetes.

Disclosure

J. Q. Matuschek: None. H. A. Russ: Consultant; Eli Lilly and Company, Sigilon Therapeutics, Inc. T. M. Triolo: None. A. W. Michels: Employee; ImmunoMolecular Therapeutics, Stock/Shareholder; ImmunoMolecular Therapeutics. K. Mcdaniel: None. M. S. Hansen: None. S. Williams: None. R. Castro-gutierrez: None. A. Shilleh: None.

Funding

NIH: K12DK094712
194-OR: The Effect of Level of Spinal Cord Injury on the Prevalence of Diabetes
Authors: TRBOVICH MICHELLE , DIMAS RUDI , MADER MICHAEL J. , SALEHI MARZIEH
Published: May 2022

Persons with spinal cord injury (SCI) develop diabetes at much higher rates than those with able bodies. Glycemic effect of SCI is exaggerated in those with higher level of injury (LOI) (e.g.: tetraplegia [TP]) compared to those with lower LOI (e.g.; paraplegia [PP]) . We hypothesized that prevalence and incidence of diabetes is higher in those with higher LOI among SCI patients. In a retrospective cohort study of veterans with spinal cord injury, from 20to 2021, electronic record data on weight, height, gender, ethnicity, level of injury (TP vs. PP) , glucose and A1C levels, and antidiabetic medications were obtained. Diabetes was defined by random glucose >200 mg/dl and HbA1C>6.5%. A total of 9persons with SCI were identified (440 TP/ 471 PP,48 F/863 M, age (22-90) , BMI (13.1-51.4)) . The prevalence of diabetes at the first visit among those with TP and PP was similar (21vs. 20%) . Among 728 nondiabetic subjects with SCI, 1 (34%) with TP vs. 127 (34%) with PP developed type 2 diabetes over a median period of 40m (18-93) vs. 39m (15-75) (p=0.3) . Groups were similar for age and gender distribution, but PP had greater BMI compared to TP (p<0.01) . Despite similar A1C and plasma glycemia between the 2 groups at their first encounters, PP subjects had higher glycemic control estimated by A1C at the time of DM conversion or their last encounter (6.4± 1.7% vs. 6.0± 1.1%, p<0.05) . Of note, a larger number of diabetic patients in this cohort did not receive any antidiabetes medications (76% in TP/ 65% in PP, p=0.09) . At the end of 20-year study period, there were a total of 72 deaths in TP patients with diabetes compared to 60 deaths in PP patients with diabetes (61% vs. 47%, p<0.05) . Our findings indicate that despite greater amount of innervated lean muscle mass and lesser impaired autonomic nervous signaling in persons with PP compared to TP, rate of diabetes development and glycemic control are relatively similar among those with the high and low LOI. However, among SCI patients with diabetes those with TP had worse survival rate than PP.

Disclosure

M.Trbovich: None. R.Dimas: None. M.J.Mader: None. M.Salehi: None.
202-OR: Early De Novo DNA Methylation Patterning Regulates Adult Beta-Cell Function and Survival Programs
Authors: PARVEEN NAZIA , WANG JEAN K. , HAM ALEXANDER P. , DHAWAN SANGEETA
Published: May 2022

DNA methylation is an important epigenetic mechanism that controls transcriptional programs to direct cell phenotype. Dynamic, stage-specific changes in DNA methylation coordinate the gene-expression patterns associated with cell differentiation throughout development. Our prior work has shown that the establishment of new DNA methylation patterns is essential for functional maturation of beta cells in postnatal life, while maintenance of existing methylation patterns sustains beta cell identity. While maintenance of DNA methylation in pancreatic progenitors is essential for their survival during differentiation, the requirement for new DNA methylation patterns in pancreatic progenitors has not been investigated. To address this, we generated pancreatic progenitor specific ablation of the de novo DNA methyltransferase, Dnmt3a, an enzyme that establishes new DNA methylation patterns, using Pdx1-Cre (Dnmt3aPKO) . RNA-sequencing of the Dnmt3aPKO islets reveals that early loss of Dnmt3a alters the beta cell identity, function, and survival programs. In addition, we observe the upregulation of genes associated with dopamine signaling and disruption of imprinted gene expression in the KO islets. Several of these gene-expression changes are distinct from those observed upon beta cell specific ablation of Dnmt3a, suggesting the unique contribution of early patterning to adult beta cell phenotype. Genome-wide profiling of DNA methylation patterns using reduced representation bisulfite sequencing (RRBS) in the Dnmt3aPKO islets points to disruption of similar programs associated with cell identity and function. These data also reveal interesting differences in the DNA methylation patterns in male and female Dnmt3aPKO mice. Collectively, our data suggest that stage specific DNA methylation patterning during beta cell differentiation controls specific aspects of the mature beta cell phenotype.

Disclosure

N.Parveen: None. J.K.Wang: None. A.P.Ham: None. S.Dhawan: None.

Funding

National Institutes of Health (R01-DK120523)
205-LB: ERK Is Required for LPS-Induced TLR4 Internalization in Macrophages
Authors: CHANG PHOEBE F. , REYNA SARA M.
Published: May 2022

Insulin resistance is associated with circulating levels of lipopolysaccharide (LPS) released from the gut. Animal and human studies demonstrate that obesity increases gut permeability leading to elevated plasma LPS levels resulting in inflammation and metabolic dysfunction. Binding of LPS to Toll like receptor 4 (TLR4) leads to the internalization and trafficking of TLR4, inducing activation of downstream signaling pathways. TLR4 internalization in macrophages leads to activation of pro-inflammatory signaling pathways and production of factors linked to the development of insulin resistance. The extracellular signal-regulated kinase 1 and 2 (ERK1 and 2) are activated downstream of TLR4 and this activation is associated with insulin resistance. We hypothesized that ERK1 and ERK2 regulate TLR4 internalization in macrophages that are exposed to LPS. We examined whether inhibition of ERK activity blocks LPS-mediated internalization of TLR4 in bone marrow derived macrophages (BMDM) .We used siRNA to knockdown ERK1, ERK2, or both. BMDM were treated with LPS (100 ng/ml, 6hr) . Loss of cell surface TLR4 expression was measured by flow cytometry as a readout for TLR4 internalization. LPS decreased TLR4 surface expression by 31.3%, but knockdown of ERK1, ERK2, or both prevented LPS-induced decrease of TLR4 surface expression (5.6%, no decrease, 0.9%, respectively) . In addition, knockdown of either ERK1, ERK2, or both in RAW264.7 cells prevented LPS-induced activity of Rab5, the early endosomal protein associated with TLR4 translocation.

In summary, ERK regulates TLR4 endocytosis and trafficking in macrophages. We propose that ERK positively regulates LPS-mediated TLR4 internalization and inhibition of ERK signaling will protect against insulin resistance.

Disclosure

P. F. Chang: n/a. S. M. Reyna: n/a.

Funding

National Institutes of Health (SC2GM127272)
213-LB: Combined Oral Contraceptives Drive Inactivity and Hepatic Mitochondrial Oxidative Stress in Female Mice
Authors: FULLER KELLY , MCCOIN COLIN S. , STIERWALT HARRISON , THYFAULT JOHN P.
Published: May 2022

Background: It is well established that compared to age-matched men, pre-menopausal women are protected against metabolic disease (obesity, diabetes, hepatic steatosis) . However, both epidemiological data on menopause and pre-clinical ovariectomy models show that disruption of estrogen signaling increases disease susceptibility. Combined oral hormonal contraceptives (OC) induce loss of normal estrogen cycling, and despite widespread use, the impact of OCs on metabolic health and disease remains poorly understood.

Methods: Female C57BL/6J mice (7-8 wks old) were treated with high-fat diet (HFD; CON) or HFD + OCs (2mg estradiol/kg HFD, 200mg progestin/kg HFD; OC) for 12 wks. In each treatment group, mice either remained sedentary or had access to voluntary running wheels (VWR; n=12 per group) . Liver and skeletal muscle mitochondrial function (respiratory capacity, H2O2, coupling) were measured along with body composition, glucose tolerance, energy expenditure, and intrahepatic triglyceride.

Results: OCs decreased VWR, spontaneous physical activity, and total energy expenditure. OC treated mice had lower adiposity and hepatic triglyceride compared to CON mice, with no difference in glucose tolerance. Despite similar maximal respiratory capacity, OCs induced robust increases in hepatic mitochondrial H2O2 across all respiratory states and with both fat and carbohydrate-based substrates. There were no differences in muscle mitochondrial outcomes.

Conclusions: When combined with HFD, OC use lowers physical activity and energy expenditure while inducing tissue-specific effects on mitochondrial function in mice. These data provide pause for use of OCs in the context of elevated metabolic disease risk. Future work should explore whether OC-induced changes in physical activity blunts the ability of exercise to prevent or treat insulin resistance and steatosis and whether prolonged OC exposure leads to liver injury via elevated oxidative stress.

Disclosure

K. Fuller: None. C. S. Mccoin: None. H. Stierwalt: None. J. P. Thyfault: None.

Funding

AHA (20PRE35120098) , VA Merit Review Grant (1I01BX002567-01)
217-LB: Hepatic Mig6 Ablation Restores Glucose Homeostasis during Diet-Induced Obesity and Aging
Authors: IRIMIA-DOMINGUEZ JOSE M. , BLOOM-SALDANA ELIZABETH A. , FUEGER PATRICK T.
Published: May 2022

Hepatic epidermal growth factor receptor (EGFR) expression and activation are decreased during steatosis in humans and animal models of obesity. Restoring EGFR activation in obesity-induced endoplasmic reticulum (ER) stress and diabetes is a potential therapy to improve liver function and metabolism in type 2 diabetes (T2D) . Mitogen-inducible gene 6 (Mig6) is an inducible feedback inhibitor of EGFR activity; we previously observed that liver Mig6 expression was increased during obesity-induced insulin resistance in mice and by both pharmacological- and fatty acid-driven ER stress in hepatocytes, leading to decreased EGF-mediated EGFR activation. To test Mig6 as a potential target to treat insulin resistance in T2D, we examined liver-specific Mig6 knockout mice (LKO) and their littermate controls (CON) . LKO mice exhibited reduced liver fat content and normalized glycogen storage with diet-induced obesity. In addition, we observed enhanced hepatic insulin action and whole-body glucose tolerance, due to increased hepatic glucose uptake, as determined by hyperinsulinemic-euglycemic clamps. Using whole transcriptome sequencing, peroxisomal and mitochondrial beta-oxidation genes were decreased by Mig6 ablation, correlating with a compromised gene expression of liver gluconeogenic enzymes. Moreover, analysis of mice aged for one year, a different physiological insult causing insulin resistance and liver oxidative stress, we were able to recapitulate the main findings as with diet-induced obesity: decreased gluconeogenesis, enhanced liver glucose uptake leading to increased glucose tolerance. Moreover, in aged LKO mice, liver oxidative stress markers were reduced. In conclusion, we postulate that hepatic Mig6 deficiency partially reverts the effects of diabetes by decreasing hepatic glucose output and reducing cellular oxidative stress, thereby establishing Mig6 as a therapeutic candidate for treating insulin resistance in obesity and T2D.

Disclosure

J. M. Irimia-dominguez: None. E. A. Bloom-saldana: None. P. T. Fueger: Consultant; Protomer Technologies.
218-LB: Remission of Type 2 Diabetes after Weight Loss in "Normal" Weight People—The ReTUNE Study
Authors: TAYLOR ROY , IRVINE KEATON M. , BARNES ALISON C. , KELLY TARA L. , CLARK LUCY G. , HOLLINGSWORTH KIEREN G. , AL-MRABEH AHMAD , HOLMAN RURY R. , ROMERES DAVIDE , COBELLI CLAUDIO
Published: May 2022

Background and aims: Mechanisms underlying weight loss induced remission of type 2 diabetes (T2DM) have been reported only in people with BMI >27kg/m2. The Personal Fat Threshold hypothesis postulated that the same mechanisms in people with BMI <27kg/m2. Pathophysiology during stepwise dietary weight loss was studied in this group.

Methods: People with T2DM (13/20 female, mean (±1SD) 59.3±7.1 years, BMI 24.8±1.7kg/m2) were studied before and after up to three 5% weight loss cycles, each comprising a 2-4 week low energy diet (800kcal/day formula meal replacements plus non starchy vegetables) , followed by 4-6 weeks of weight maintenance. All hypoglycemic agents were stopped before weight loss. Studies were repeated at 12 months. Outcomes were compared to normoglycemic matched controls (n=20) . Intrahepatic and intrapancreatic fat was quantified by magnetic resonance, and a standard meal test assessed insulin secretion by Disposition Index (DI) .

Results: 70% achieved remission (HbA1c <6.5%; 14/20) , accompanied by decrease in adipose tissue distress (Median (IQR) PAI-1 8.64 (6.97-11.01) to 5.99 (3.94--7.73) p<0.02 [control 4.87 (3.49-7.03] ng/ml; GDF-15 591 (439-872) to 444 (395-554) [446 (383-614] pg/ml p<0.05. Between baseline and 12 months, decrease was (mean±SE; control data in square brackets) : BMI 24.8±0.4 to 22.5±0.4 kg/m2 (p<0.0001) [21.5±0.5]; total body fat 32.1±1.5 to 27.6±1.8% (p<0.0001) [24.6±1.5]; Fasting plasma insulin 47±6 to 24±6pmol/l (p<0.001) [23±2]; liver fat 4.0±0.6 to 1.6±0.2% (p=0.02) [1.9±0.3]; plasma triglycerides 1.4±0.2 to 0.9±0.1mmol/l (p<0.02) [0.9±0.1]; Intrapancreatic fat (6.1±0.5 to 5.0±0.6% (p=0.03) [4.1±0.3]. DI increased from median (IQR) 289 (183-373) to 774 (486-1709) dl/kg/min per pmol/l (p<0.05) but remained subnormal [2751 (1524-3526].

Conclusion: Mechanistic changes underpinning remission after weight loss in non-obese people with T2DM are the same as in obese people. T2DM occurs if a person becomes too heavy for their own constitution, irrespective of BMI. Weight loss of ∼10% can bring about T2DM remission in people classified as having a ‘normal’ BMI.

Disclosure

R. Taylor: Speaker's Bureau; Janssen Global Services, LLC, Lilly Diabetes, Nestlé Health Science, Novartis AG. C. Cobelli: None. K. M. Irvine: None. A. C. Barnes: None. T. L. Kelly: None. L. G. Clark: None. K. G. Hollingsworth: None. A. Al-mrabeh: None. R. R. Holman: Advisory Panel; Anji Pharmaceuticals, Novartis AG, Novo Nordisk, Consultant; AstraZeneca, Research Support; AstraZeneca, Bayer AG, Merck Sharp & Dohme Corp. D. Romeres: None.

Funding

Diabetes UK (17/0005645)
220-OR: Characteristics Associated with Adding Insulin in Type 2 Diabetes in the Glycemia Reduction Approaches in Diabetes (GRADE) Study
Authors: MARTIN CATHERINE , HOLLANDER PRISCILLA A. , KRAUSE-STEINRAUF HEIDI , KAZEMI ERIN , BUTERA NICOLE M. , AHMANN ANDREW , FALCK-YTTER CORINNA , FATTALEH BASMA , JOHNSON MARY L. , KILLEAN TINA , LAGARI VIOLET , LARKIN MARY E. , LEGOWSKI ELIZABETH , RASOULI NEDA , WILLIS HOLLY ,   GRADE RESEARCH GROUP
Published: May 2022

Delaying insulin when indicated in type 2 diabetes (T2D) prolongs exposure to hyperglycemia. In the GRADE study, adults (N=5047) with T2D (duration <years, metformin monotherapy, HbA1c 6.8 to 8.5%) were randomly assigned to glimepiride, sitagliptin, liraglutide or insulin glargine U-100 and followed for mean and median of 5 years. The protocol specified addition of basal insulin glargine (non-insulin groups) or prandial insulin aspart (glargine group) ≤6 weeks after confirming the outcome of A1c>7.5%. Written consent included acceptance of injectable medications, including insulin, and to add or intensify insulin therapy after outcome confirmation. Among 2387 participants with confirmed A1c>7.5%, 834 (35.0%) added insulin within 6 weeks, 698 (29.1%) after 6 weeks, and 855 (35.8%) never. When we did a comparison by time of initiation, there were differences by age, racial group, outcome A1c and assigned treatment group. Participants never adding insulin were more likely to be older, Black/African American, or assigned to glargine. Those who added insulin were more likely to have higher confirmation A1cs or be assigned to sitagliptin. Analyses to explore investigator and participant factors influencing decisions to delay or not add insulin despite suboptimal glucose control are underway.

Disclosure

C. Martin: Advisory Panel; Nevro Corp. P.A. Hollander: None. H. Krause-Steinrauf: None. N.M. Butera: None. A. Ahmann: Advisory Panel; Medtronic. C. Falck-Ytter: None. B. Fattaleh: None. M.L. Johnson: Research Support; Abbott Diabetes, Dexcom, Inc., Insulet Corporation, Jaeb Center for Health Research, Lilly, Medtronic, Novo Nordisk, Sanofi. V. Lagari: None. M.E. Larkin: None. N. Rasouli: Advisory Panel; Eli Lilly and Company, Novo Nordisk, Sanofi. Research Support; Allergan, Eli Lilly and Company, Novo Nordisk. H. Willis: Research Support; Abbott Diabetes, Sanofi.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (U01DK098246, U34-DK-088043)
224-OR: Antisense Oligonucleotide–Mediated Restriction of Mitochondrial Pyruvate Metabolism Limits DNL in High-Fat Fed C57BL6/J Mice
Authors: STROBER JORDAN W. , PAOLELLA LAUREN M. , SUH REBECCA , HUBBARD BRANDON T. , MURRAY SUE , VATNER DANIEL F.
Published: May 2022

Increased de novo lipogenesis (DNL) contributes to lipid disturbances prevalent in insulin resistant (IR) subjects, including dyslipidemia and NAFLD; however, the specific carbon sources that maintain DNL during hepatic IR remain unknown. To address this question, antisense oligonucleotides (ASOs) targeting glucokinase (GCK) , ketohexokinase (KHK) , lactate dehydrogenase (LDHA) , and glutamic-pyruvic transaminase 2 (GPT2) were applied to restrict substrate influx from specific lipogenic precursors. Subsequently, the rates of DNL were assessed via the deuterated water method, and triglyceride (TG) content was measured in both insulin-sensitive regular chow (RC) fed and IR six-week high-fat diet (HFD) fed C57BL6/J mice. In RC mice, there were no significant differences in hepatic DNL as a result of treatment with any ASO. Furthermore, TG content remained unchanged by most ASOs in the RC cohort, but was increased in the liver with the LDHA ASO (Con: 7.4±0.2 μg/mg; LDHA: 16.9±1.2 μg/mg; p<.001) and decreased in circulation with the GCK ASO (Con:84.8±6.3 mg/dL; GCK:54.5±5.8 mg/dL; p<.01) . In the HFD cohort, DNL, hepatic TG content, and circulating TGs were all reduced by restricting lipogenic carbon entry from glucose (GCK ASO vs. Con: DNL -69.2%±3.6, p<.01; Hep TG -59.2%±4.4, p<.05; Cir TG -35.7%±3.7, p<.001) , lactate (LDHA ASO vs. Con: DNL -33.1%±9.1, p<.05; Hep TG -25.8%±7.4, p<.05; Cir TG -18.0%±8.0, NS) , and alanine (GPT2 ASO vs. Con: DNL -48.1%±9.8, p<.01; Hep TG -45.5%±8.9, p<.01; Cir TG -23.2%±5.3, p<.01) .

Conclusion: RC fed mice maintain DNL despite restricting specific carbon precursors; however, in HFD-fed mice, glucose, lactate, and alanine are all necessary substrates for maintaining aberrantly elevated rates of DNL, and any substrate restraint is associated with reduced DNL. These findings expound how specific carbon fluxes support DNL in IR and may inform the development of novel therapies for dyslipidemia.

Disclosure

J.W.Strober: None. L.M.Paolella: None. R.Suh: None. B.T.Hubbard: None. S.Murray: Employee; Ionis Pharmaceuticals. D.F.Vatner: None.

Funding

NIH T32 (DK007058) NIH R (DK124272)
226-LB: Genetic Variation of Human Myokine Signaling Is Dominated by Biologic Sex and Sex Hormones
Authors: VAN CASSANDRA , SELDIN MARCUS
Published: May 2022

Skeletal muscle physiology is a critical determinant and therapeutic target for type 2 diabetes. Proteins secreted from skeletal muscle, termed myokines, allow the muscle to communicate with other key metabolic organs and several have been established as causal drivers of processes such as exercise and lipid metabolism. Yet, the genetic architecture, regulation, and functions of myokines, as well as degree of conservation of these communication circuits remains inadequately understood. In this study, we performed the first targeted genetic survey of myokine gene regulation and cross-tissue signaling in 310 humans where sex as a biological variable was emphasized. While expression levels of a majority of myokines and cell proportions within skeletal muscle showed little differences between males and females, nearly all significant cross-tissue enrichments operated in a sex-specific or hormone-dependent fashion. Estrogen signaling specifically in muscle showed striking enrichments with myokines, independent of sex-specific signaling. To define the causal roles of estrogen signaling on myokine gene expression and functions, we generated male and female mice lacking estrogen receptor α (Esr1) specifically in skeletal muscle and integrated global RNA-Sequencing with human data. These analyses highlighted mechanisms of sex-dependent myokine signaling conserved between species, such as myostatin enriched for divergent substrate utilization pathways between sexes, and GPX3 as a male-specific link between glycolytic fiber abundance and hepatic inflammation. Collectively, we provide the first genetic survey of human myokines and highlight sex and estrogen receptor signaling as critical variables when assaying myokine functions and how changes in cell composition impact other metabolic organs. This study is currently available on bioRxiv: https://www.biorxiv.org/content/10.1101/2022.01.20.477045v1

Disclosure

C. Van: None. M. Seldin: None.
229-LB: G6PC2, a GWAS Locus for Fasting Glucose and HbA1c, Regulates Glucose-Suppression of Glucagon Secretion in a-Cells
Authors: BAHL VARUN , MAY CATHERINE L. , PANCREAS ANALYSIS PROGRAM HUMAN , KAESTNER KLAUS H.
Published: May 2022

The G6PC2 locus, encoding the catalytic subunit of the islet-specific glucose-6-phosphatase enzyme, is an established risk locus for HbA1c and fasting glucose levels. A critical role of glycolytic flux in regulating glucagon secretion was established through manipulation of the activity and expression of the glycolytic enzyme glucokinase (GCK) which controls the setpoint for glucose-suppression of glucagon secretion (GSGS) . G6PC2 opposes the action of GCK by hydrolyzing glucose-6-phosphate back to glucose and creating a futile substrate cycle. Previous studies from germline and β-cell-specific G6PC2 null mice have demonstrated that G6PC2 ablation reduces glucose-6-phosphatase activity, glucose cycling, and glycolytic flux, resulting in a leftward shift of dose-response curve for glucose-stimulated insulin secretion. Through cell type specific chromatin accessibility maps of sorted human islet cells, we established that G6PC2 risk SNPs are in open chromatin regions in human α-cells, suggesting that they might not only affect β-cell but also α-cell expression of this critical gene. To test whether α-cell G6PC2 impacts glycemic control, we derived a new mouse line that induces ablation of the first three exons of G6PC2 after Cre activation – resulting in a null allele (G6pc2 loxP/loxP; Gcg-CreERT2; referred to as “α-G6PC2KO”) . Assessment of glucagonemia during glucose tolerance tests revealed a decrease in glucagon levels in α-G6PC2KO mice relative to controls. Intriguingly, fasting blood glucose levels were significantly lower in α-G6PC2KO mice. α-G6PC2KO mice recovered more slowly from hypoglycemia during an insulin tolerance test, and presented lower glucagon levels relative to control mice following the insulin bolus. α-G6PC2KO islets secreted less glucagon relative to control islets when incubated in low-glucose media, independent of alterations in insulin secretion or islet hormone content. Collectively, our data demonstrate that the G6PC2 locus impacts glycemic control via its action in α-cells.

Disclosure

V. Bahl: None. C. L. May: None. Human pancreas analysis program: n/a. K. H. Kaestner: None.
23-LB: A Study of Taste among Type 2 Diabetes Mellitus Patients with Autonomic Neuropathy at a Tertiary Care Centre in North India
Authors: KUSHWAHA JITENDRA , SINGH ARCHANA , GIRI RICHA , GUPTA VISHAL K.
Published: May 2022

Introduction: Type 2 diabetes mellitus (T2DM) is a multifactorial, complex disease associated with chronic hyperglycemia, resulting from the interplay of genetic, environmental, and epigenetic factors (1) . Diabetic autonomic neuropathy (DAN) is one of the common complication in diabetes. The taste threshold affected by various factors such as age, ethnic backgrounds, drugs, local and systemic diseases, consumption of alcohol, smoking, and tobacco chewing . The present study is undertaken with the objectives to compare the alteration in taste threshold for four primary sensations in Type 2 DM with autonomic neuropathy.

Material and methods: 60 patients of T2DM with autonomic neuropathy and 60 healthy control were taken for the study. Autonomic neuropathy were assessed clinically. Chemical taste test using four solutions of basic tastes (sweet, sour, salty, bitter) were done. 5 ml sample of each solution was provided whose nature was kept unknown to the subject and asked to hold it there for 5 seconds before spitting the solution into the cup.

Result: Out of 60 patients 26 (43.3%) were having taste dysfunction for sweet compared to 12 (20%) out of 60 healthy controls with p value 0.006. Taste dysfunction for sweet was significant in T2DM with uncontrolled hyperglycemia i.e mean HbA1c 10.83+/- 3.17 whereas in T2DM patients whose taste were preserved had mean HbA1c 8.05+/- 1.87 . The taste dysfunction in T2DM patients was not related to gender, disease duration, and type of treatment taken.

Conclusion: The study found a significant correlation between taste dysfunction, HbA1C level and blood sugar fasting level in T2DM patients. The taste dysfunction was mainly for sweet. Sour and bitter did not show any difference in case groups compared to controls.

Disclosure

J. Kushwaha: None. A. Singh: None. R. Giri: None. V. K. Gupta: None.
231-LB: GLP-1 Promotes Cortical and Medullary Perfusion in Human Kidney and Maintains Tissue Oxygenation during Na Loading
Authors: HADDOCK BRYAN , JENSEN BOYE L. , ASMAR ALI
Published: May 2022

Purpose: GLP-1 receptor agonism has shown beneficial cardiovascular effects which could include the kidneys. In the human kidney, the high GLP-1 extraction and its natriuretic effect depend on the GLP-1 receptor and is accompanied by suppression of angiotensin II, independent of changes in renal plasma flow. Preclinical data showed that angiotensin II constricts the vasa recta and lowers medullary perfusion. The current randomized, controlled study was designed to test the hypothesis that GLP-1 increases renal medullary perfusion in healthy humans.

Methods: Healthy male participants (n=10, 27 ± 4 years) ingested a fixed sodium intake for 4 days and were examined twice during a 1-hour infusion of either GLP-1 (1.5 pmol/kg/min) or placebo together with infusion of 0.9% NaCl (750 mL/h) . Interleaved measurements of renal artery flow, oxygenation (R2*) , and perfusion were acquired in the renal cortex and medulla during infusions, using magnetic resonance imaging.

Results: GLP-1 infusion increased medullary perfusion (32 ± 7%, p<0.001) and cortical perfusion (13 ± 4%, p<0.001) compared to placebo. Here, NaCl infusion decreased medullary perfusion (-5 ± 2%, p=0.007) while cortical perfusion remained unchanged. R2* values increased by 3 ± 2% (p=0.025) in the medulla and 4 ± 1% (p=0.008) in the cortex during placebo, indicative of decreased oxygenation but remained unchanged during GLP-1. Renal arterial blood flow was not altered significantly by either intervention.

Conclusions: GLP-1 increases predominantly medullary but also cortical perfusion in healthy human kidneys and maintains oxygenation during NaCl-loading. In perspective, GLP-1 may exert protective effects against renal hypoperfusion and ischemia.

Disclosure

B. Haddock: n/a. B. L. Jensen: None. A. Asmar: None.
233-LB: Ranolazine Fails to Improve Glycemia in Obese Liver-Specific Pyruvate Dehydrogenase–Deficient Mice
Authors: SAED CHRISTINA T. , AMIRHOSSEIN TABATABAEI DAKHILI SEYED , GREENWELL AMANDA A. , CHAN JORDAN S.F. , YANG KUNYAN , GOPAL KESHAV , EATON FARAH , USSHER JOHN R.
Published: May 2022

Background: Nonalcoholic fatty liver disease (NAFLD) increases risk for obesity-related insulin resistance and type 2 diabetes. Recent studies have demonstrated that stimulating pyruvate dehydrogenase (PDH) , the rate-limiting enzyme in glucose oxidation, can reverse obesity-induced NAFLD. Moreover, our lab has observed that treatment with the antianginal drug, ranolazine, augments hepatic PDH activity, leading to a reversal of obesity-induced glucose intolerance and NAFLD in mice. Our aim herein was to determine whether ranolazine's ability to mitigate obesity-induced NAFLD and hyperglycemia requires increases in hepatic PDH activity.

Methods: We generated liver-specific PDH deficient (PDHLiver-/-) mice by crossing floxed Pdha1 mice with albumin-Cre (Alb-Cre) mice. PDHLiver-/- and Alb-Cre mice were placed on a high-fat diet for 12-weeks to induce obesity, whereas their lean controls were fed a low-fat diet. Mice were randomized to treatment with either vehicle control or ranolazine (50 mg/kg) once daily via oral gavage for 5-weeks, following which we assessed glucose homeostasis and hepatic steatosis.

Results: Lean PDHLiver-/- mice exhibited no overt phenotypic differences (e.g. adiposity, glucose tolerance) from their Alb-Cre littermates, though a mild but nonsignificant worsening of pyruvate tolerance was observed. Similar findings were observed in obese PDHLiver-/- mice compared to their Alb-Cre littermates. Of interest, ranolazine treatment produced mild improvements in glucose tolerance in obese Alb-Cre mice, but not in obese PDHLiver-/- mice. However, this improvement in ranolazine treated Alb-Cre mice appears to be independent of decreases in hepatic triacylglycerol content.

Conclusions: Although hepatic PDH activity appears to contribute to the glucose-lowering actions of ranolazine, this appears to be dissociated from its actions on hepatic steatosis, and impaired hepatic PDH activity per se is not sufficient to produce an NAFLD phenotype.

Disclosure

C. T. Saed: None. S. Tabatabaei dakhili: None. A. A. Greenwell: None. J. S. F. Chan: None. K. Yang: None. K. Gopal: None. F. Eaton: None. J. R. Ussher: None.
239-OR: Physical Activity, Hypoglycemia, and Type 1 Diabetes: A Data-Driven Approach
Authors: PRASANNA SAHANA , BARUA SOUPTIK , JOHNSON JEREMIAH J. , SILLER ALEJANDRO F. , SABHARWAL ASHUTOSH , DESALVO DANIEL
Published: May 2022

Physical activity (PA) provides numerous health benefits for individuals with T1D. However, the threat of exercise-induced hypoglycemia may impede the desire for regular PA. We aimed to study the association between three common types of PA (walking, running, and cycling) and hypoglycemia risk in 50 individuals with T1D. Real-world data including characteristics of PA, CGM values, and insulin doses were available from the Tidepool Big Data Donation Project. Participants were aged 38.0 ± 13.1 yrs with 21.4 ± 12.9 yr duration of diabetes and avg 26.2 weeks of CGM data available.

We built a linear regression model for each of the three PA types to predict the probability of level 1 hypoglycemia (<70 mg/dL) during the 2 hours after start of PA using the following predictors: PA duration (mins) , PA intensity (calories burned) , 2-hr pre-exercise glucose AUC, glucose value at start of PA, and total bolus insulin within 2 hrs before PA.

Regression results are provided in Table 1. Our models indicated that glucose value at the start of exercise (p<0.0for all three activities) and pre-exercise glucose AUC (p<0.0for walking and cycling) were the most significant predictors of hypoglycemia. Duration and intensity of PA and 2-hr bolus insulin were weakly associated with hypoglycemia for certain exercises. These findings may provide T1D individuals with a data-driven approach in preparing for PA that minimizes hypoglycemia risk.

Disclosure

S.Prasanna: None. S.Barua: None. J.J.Johnson: None. A.F.Siller: None. A.Sabharwal: None. D.Desalvo: Consultant; Dexcom, Inc., Insulet Corporation, Research Support; Insulet Corporation.

Funding

National Science Foundation (1648451)
24-OR: Podocyte Targeted Pyruvate Kinase M2 (PKM2) Activation Normalized Glomerular VEGF Expression, Mitochondrial Function, Fuel Metabolism, and Diabetic Nephropathy
Authors: FU JIALIN , SHINJO TAKANORI , LI QIAN , PARK KYOUNGMIN , YU MARC GREGORY , YOKOMIZO HISASHI , HUANG QIAN , WU I-HSIEN , KING GEORGE L.
Published: May 2022

Diabetic nephropathy (DN) is the result of abnormal systemic and local changes in metabolism and hemodynamics. We have reported that many glycolytic enzymes, such as pyruvate kinase M2 (PKM2) , were elevated in the renal glomeruli of type 1 and type 2 diabetic patients who were protected from DN. TEPP46, a small-molecule which activates PKM2 by inducing oligomerization, reversed glomerular pathology in diabetic mice. Here, mice with PKM2-specific overexpression in podocytes (PPKM2Tg) were generated to uncover its renal protective function as potential therapeutic target, which prevented elevated albumin-creatinine ratio (ACR) , mesangial expansion, basement membrane thickness and podocyte foot process effacement after 7-months of STZ-induced diabetes. Further, diabetes-induced impairment of glycolytic rate and mitochondrial function were normalized in diabetic PPKM2Tg glomeruli, in concordance with elevated Ppargc1a and Vegf expressions. Restored VEGF expression improved glomerular maximal mitochondrial function in diabetic PPKM2Tg and WT mice. Elevated VEGF levels were observed in the glomeruli of DN-protected patients with chronic type 1 diabetes, and clinically correlated with estimated GFR, but not glycemic control. Mechanistically, the preservations of mitochondrial function and VEGF expression were dependent on tetrameric structure and enzymatic activities of PKM2 in podocyte. Thus, these findings show that PKM2 activation in the podocyte can regulate mitochondrial metabolism of the entire glomeruli and prevent mitochondrial dysfunction induced by chronic diabetes and even reverse metabolic memory. PKM2 structures and enzymatic activities are necessary to mediate glomerular metabolism against toxicity of hyperglycemia via paracrine factors such as VEGF. Thus, PKM2 activation in podocyte is a potential therapeutic target to protect against DN.

Disclosure

J.Fu: None. T.Shinjo: None. Q.Li: None. K.Park: None. M.Yu: None. H.Yokomizo: None. Q.Huang: None. I.Wu: None. G.L.King: Advisory Panel; Medtronic, Research Support; Janssen Pharmaceuticals, Inc.
240-OR: Quantifying Glucose Utilization and Endogenous Glucose Production during Resistance Exercise in People with Type 1 Diabetes (T1D)
Authors: YOUNG GAVIN , JACOBS PETER G. , TYLER NICHOLE S. , NGUYEN THANH-TIN P. , CASTLE JESSICA R. , WILSON LEAH M. , BRANIGAN DEBORAH , GABO VIRGINIA , GUILLOT FLORIAN H. , RIDDELL MICHAEL , YOUSSEF JOSEPH EL
Published: May 2022

Glucose dynamics during and after resistance exercise in people with T1D is not well understood. We recruited 25 people with T1D to perform 3 separate sessions of in-clinic resistance exercise under low (basal) , medium (1.5x basal) , or high (3.0x basal) insulin infusion levels. Blood glucose was clamped by intravenous dextrose infusion 3 hours prior to, and 4 hours after a 45-minute session of strength training. Glucose tracer was infused to match the rate of endogenous glucose production (EGP) . Glucose and tracer data were used to fit a two-compartment model and quantify the rate of glucose disposal (Rd) and EGP. For 58 sessions across 25 participants, blood glucose levels remained constant during and after resistance exercise. The mean change in area under the curve (AUC) for Rd was not higher during resistance exercise compared to baseline (+1.2 mM, p=0.69) , but increased during previously published aerobic exercise (+12.5 mM, p<0.01) . Mean AUC for EGP rose during resistance exercise (+6.5 mM, p<0.01) primarily due to non-insulin mediated factors and the increase was higher than during aerobic exercise (+2.mM, p<0.01) . Resistance exercise is characterized by a strong rise in EGP that is predominantly driven by non-insulin mediated effects. This may mitigate drops in blood glucose caused by increased glucose utilization in peripheral tissues during anaerobic activity.

Disclosure

G.Young: None. M.Riddell: Advisory Panel; Zealand Pharma A/S, Zucara Therapeutics, Consultant; Eli Lilly and Company, Jaeb Center for Health Research, Speaker's Bureau; Dexcom, Inc., Eli Lilly and Company, Novo Nordisk. J.El youssef: None. P.G.Jacobs: Other Relationship; Pacific Diabetes Technologies, Research Support; Dexcom, Inc. N.S.Tyler: None. T.P.Nguyen: None. J.R.Castle: Advisory Panel; Insulet Corporation, Novo Nordisk, Zealand Pharma A/S, Stock/Shareholder; Pacific Diabetes Technologies. L.M.Wilson: n/a. D.Branigan: None. V.Gabo: None. F.H.Guillot: Stock/Shareholder; Pacific Diabetes Technologies.

Funding

National Institutes of Health (5R01DK110175, 1F30DK128914)