bluuebunny/crossref_metadata_2025_split huggingface dataset:
163-OR: Evidence for Circadian Control of Glucose-Stimulated Insulin Secretion in Transplanted Human Stem-Cell-Derived Pancreatic ß-Cells
Authors: SEN SATISH K. , HASSOUN SHAIMAA , PETERSON QUINN P. , MATVEYENKO ALEKSEY 
Published: June 2021

Cell replacement strategies utilizing stem cell-derived β-cells (SC-β cells) hold therapeutic potential for patients with diabetes. In order for cell therapy to be effective, transplanted SC-β cells must recapitulate physiological features of insulin secretion in humans. In this regard, circadian regulation of insulin release is critical for normal β cell physiology, where intrinsic β cell circadian clocks function to optimize glucose-stimulated insulin secretion (GSIS) during the active/feeding phase of the circadian cycle. Thus, to elucidate whether transplanted SC-β cells retain capacity for circadian control of insulin secretion, SC-β cells were generated using a six-step directed differentiation protocol and transplanted (n=13 independent transplants) under the kidney capsule into immunocompromised (SCID-beige) mice. Prior to transplantation, differentiated SC-β cells were confirmed to express core circadian clock genes (e.g.,BMAL1, CLOCK, PER1 and REV-ERBα). Provided this information, we next assessed in vivo glucose tolerance and corresponding insulin secretory response (using human insulin ELISA) in SCID-beige mice during the inactive/sleep and active/feeding circadian cycles. Both parameters demonstrated robust diurnal rhythmicity (p&lt;.05, inactive vs. active) with markedly enhanced glucose tolerance and in vivo SC-β cell secretory function evident during active/feeding circadian phase in mice. Notably, among 13 independent transplantations, ~90% of mice demonstrated statistically significant GSIS in response to intraperitoneal glucose injection during active/feeding compared to ~30% during inactive/sleep circadian phase. Our results provide evidence that transplanted SC-β cells retain circadian control of insulin secretion which should be taken into consideration for assessment and design of future β cell replacement strategies.

Disclosure
S. K. Sen: None. S. Hassoun: None. Q. P. Peterson: Other Relationship; Self; Semma Therapeutics, Inc. A. Matveyenko: None.

Funding
National Institutes of Health (R01DK098468 to A.M.)
164-OR: Brown Adipose Tissue as a Novel Site for Islet Transplantation
Authors: KEPPLE JESSICA , BARRA JESSIE , HUNTER CHAD S. , TSE HUBERT M. 
Published: June 2021

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin-producing β-cells. While islet transplantation is a promising alternative to insulin therapy for T1D treatment, finding ideal transplant sites that are readily accessible, exhibit glucose regulation, are immune-privileged, and promote vascularization for islet survival has remained a challenge. A novel site which exhibits these traits is the brown adipose tissue (BAT). BAT functions as a thermogenic adipose tissue that maintains body temperature and regulates metabolism. We hypothesize that murine islets transplanted into BAT will display normal islet graft and BAT function while providing immunological protection. Syngeneic transplant of 250 NOD.scid islets into the BAT of streptozotocin-treated diabetic NOD.scid mice restored euglycemia for over ten weeks, which was comparable to kidney capsule transplant controls. BAT histology and mRNA analysis assessed ten weeks after transplantation showed engrafted islets maintain expression of hallmark hormones, like insulin and glucagon, and critical transcription factors. Evaluation of BAT function after transplantation revealed no impairments in glucose and insulin tolerance, cold tolerance, or whole-body energy expenditure. Flow cytometry analysis displayed an enrichment of immunomodulatory T regulatory cells and anti-inflammatory M2 macrophages in BAT compared to kidney, possibly allowing greater immunoprotection for engrafted islets. Strikingly, adoptive transfer and allogeneic transplant studies revealed that islets transplanted into BAT showed significant delays in autoimmune and allograft rejection compared to islets transplanted under the kidney capsule. Overall, our data suggest BAT as a novel and efficacious site for islet transplantation to potentially combat T1D.

Disclosure
J. Kepple: None. J. Barra: None. C. S. Hunter: None. H. M. Tse: None.

Funding
National Institute of Diabetes and Digestive and Kidney Diseases (DK099550 to H.M.T.), (DK111483 to C.S.H.), (DK126456 to H.M.T., C.S.H.), (F31DK121414 to J.K.); JDRF (SRA-2016-270-S-B, 2-SRA-2019-692-S-B to H.M.T.); National Institute of General Medical
166-OR: Coinfusion of Mesenchymal Stem Cells Improves Human Islet Survival in the Hepatic Islet Transplantation Mouse Model
Authors: GOU WENYU , STRANGE CHARLIE , WANG HONGJUN 
Published: June 2021

Islet survival is improved when islets are co-transplanted with mesenchymal stromal cells (MSCs) under the kidney capsule. We assessed whether co-infusion of MSCs with human islets into the liver, as performed in patients, would protect those islets from death post-transplantation (PT) in streptozotocin-induced diabetic NOD-SCID mice (blood glucose, BG &gt;350mg/dl). Blood glucose levels were measured as surrogate markers for islet survival and function. Transplantation of a suboptimal islet number led to normoglycemia (BG&lt;200mg/dl) at 60 days PT in 33% of 6 mice. In contrast, 91% (n=12) of mice receiving islets co-infused with MSCs (Islet+MSC) reached and remained normoglycemic. Mice receiving islet+MSC showed lower non-fasting glucose levels, higher baseline and stimulated c-peptide levels and better function when challenged with high glucose during an intravenous glucose tolerance test. Immunohistochemistry staining of beta cells identified that significantly more islets and islet positive area were observed in the livers of islet+MSC compared to islets alone mice (even in mice with normoglycemia). We show that MSCs led to better islet survival in MSC-co-infused mice after transplantation. By using firefly luciferase-expressing MSCs, we found that co-transplanted luciferase+ (Luc+) MSC was detected up to 7 days in the liver PT. Insulin expressing MSCs were detected at 60 days PT, suggesting MSCs can stay in the liver long-term and may convert into insulin+ cells. Inflammatory-related chemokines, including IL-6, KC, and MCP-1, were also significantly reduced in islet+MSC mice serum at day 1-3 PT. The protective effects of MSC on beta cell survival was confirmed in vitro when human islets were co-cultured with MSCs in a Transwell system. These data suggest that the mechanisms of MSC protection were mediated through suppression of the innate immune response and inflammation-induced β cell death when MSC and islets were co-transplanted into the liver.

Disclosure
W. Gou: None. C. Strange: None. H. Wang: None.

Funding
National Institutes of Health (1R01DK105183, DK120394, DK118529); U.S. Department of Veterans Affairs (I01BX004536)
177-LB: The Association between the Baseline Glycemic Control and Antihyperglycemic Therapy with the Severity of SAR-CoV2 Infection in Ethnic Minority Patients with Diabetes
Authors: BERARDO JERONIMO , MIHAILESCU DAN , TAHSIN BETTINA , FOGELFELD LEON 
Published: June 2021

Objective: To analyze the relationship between the baseline glycemic control and antihyperglycemic therapy with the severity of the SARS-COV-2 infection (COVID-19) in ethnic minority patients with diabetes.
Methods: We conducted a retrospective chart review of 179 consecutive patients at an academic hospital in Chicago, Illinois. A sample of patients who tested positive for COVID-19 between March 21st, 2020 and January 12th, 2021were divided in 3 groups according to the clinical severity of COVID: 1) Mild (outpatient treatment only); 2) Moderate (hospital admission); 3) Severe (ventilatory support and/or death).
Results: Mean hemoglobin A1c (HbA1c) before COVID-19 was 8.43 (±2.0) %. Mean age was 59.6 (±11.9) years, 57.54% were male, 51.9% Hispanic and 41.9% African Americans. Sixty-four patients (35.8%) had mild disease (outpatient treatment, group 1), 93 (52%) moderate (hospital admission without the need for ventilatory support, group 2), and 22 (12.3%) severe disease (intubation and/or death, group 3). Baseline glycemic control was not associated with the clinical outcomes of COVID. Among various therapeutic agents, only metformin use was significantly associated with mild disease versus moderate and severe forms of COVID, controlling for GFR. Fifty-four patients (84.4%) in group 1 were taking metformin, compared with 63 (35%) and 11 (50%) in the moderate and severe groups, respectively.
Conclusion: Here we report that use of metformin was associated with a lower chance of developing moderate (hospitalization) or severe forms (ventilatory support and/or death) of COVID-19 in ethnic minority patients with diabetes. Prospective investigation is required to make precise estimates of the impact of metformin in COVID-19 outcomes.

Disclosure
J. Berardo: None. D. Mihailescu: None. B. Tahsin: None. L. Fogelfeld: Research Support; Self; Bayer Healthcare Pharmaceuticals Inc., Lilly Diabetes, Sanofi.
178-OR: Lipotoxicity Stimulates ß-Cell Extracellular Vesicle Secretion Which Induces ß-Cell Dysfunction and Perturbs ß-Cell Transcriptional Identity
Authors: HER TRACY K. , BROWN MATTHEW , MATVEYENKO ALEKSEY , JAVEED NAUREEN 
Published: June 2021

Chronically elevated circulating free fatty acids (FFA) contribute to β-cell dysfunction and thus to the onset of obesity-driven type 2 diabetes (T2DM). Prolonged β-cell exposure to FFA is associated with reduced glucose-stimulated insulin secretion (GSIS), alterations in β-cell transcriptional identity, and apoptosis. However, the mechanisms that contribute to the demise of β-cells under lipotoxic conditions have yet to be fully elucidated. Increasing evidence suggests that aberrant release of extracellular vesicles (EV) contribute to the pathogenesis of β-cell failure in T2DM. However, what remains to be deciphered is the role of β-cell-derived EV in lipotoxicity-mediated β-cell failure. We set out to test the hypothesis that lipotoxicity-mediated β-cell dysfunction is mediated in part by paracrine release of ‘toxic’ β-cell-derived EV. To address this, MIN6 β-cells were exposed to palmitate (0.5 mM, 24h) and EV were isolated using differential ultracentrifugation to yield palmitate (PAL) EV (vs. control (CTL) EV). Nanoparticle Tracking Analysis (NTA) revealed a significant increase in PAL EV concentration (~1.5 fold vs. CTL EV) with a reduction in average particle size (CTL EV = 121 nm vs. PAL EV = 75 nm). β-cell functional assessment of mouse islets exposed to PAL EV (48h) resulted in significant suppression of GSIS (~3.4 fold decrease in stimulation index). Global transcriptomic analysis was assessed using RNA-Seq on islets exposed to PAL EV. Over 900 genes were differentially upregulated and ~450 genes downregulated upon PAL EV exposure (p&lt;.05, FC&gt;1.5). Genes upregulated with PAL EV encoded for KEGG pathways regulating protein digestion/absorption, ECM-receptor interaction, and PI3K/Akt signaling, while downregulated genes encode for pathways regulating glycolysis and protein processing in ER (FDR&lt;.05). These data suggest the novel relevance of β-cell-derived EV in free fatty acid-induced β-cell failure in T2DM.

Disclosure
T. K. Her: None. M. Brown: None. A. Matveyenko: None. N. Javeed: None.

Funding
National Institutes of Health (R01DK098468, T32HL105355)
181-LB: Hyperglycemia at Hospital Presentation Associated with Severity and Mortality in COVID-19 Patients without Type 2 Diabetes
Authors: CHAROENNGAM NIPITH , HOLICK MICHAEL F. , APOVIAN CAROLINE 
Published: June 2021

There is a bidirectional association between hyperglycemia (HG) and COVID-19 severity. We conducted a retrospective cohort study in COVID-19 patients aged ≥18 years hospitalized at the Boston Medical Center during March 1 - August 4, 2020 with the aim to determine the relationships among HG, presence of type 2 diabetes (T2D) and outcomes of COVID-19. Blood glucose levels (BG) measured on admission were extracted from the hospital database. HG was defined as BG &gt;200 mg/dL. Patients with type 1 diabetes or BG &lt;70 mg/dL were excluded. Outcomes were in-hospital death and intensive care unit (ICU) admission. Multivariate analysis was used to determine the associations between exposures and outcomes. A total of 1,434 patients were included in the analysis. The mean ± SD age was 56 ± 17 years, 642 (45%) were female and 458 (32%) had a history of T2D. HG occurred in 193 patients with T2D (42%) and 42 patients without T2D (4%). The rates of death and ICU admission were 9% and 19%, respectively. Among patients without T2D, after adjusting for age, sex, body mass index, race and comorbidities, patients with HG had a significantly higher odds of death (aOR 4.5, 95%CI 1.8 - 11.2) and ICU admission (aOR 3.7, 95%CI 1.8 - 7.5) than patients without HG. Among patients with T2D, patients with HG had a significantly higher odds of ICU admission (aOR 1.7, 95%CI 1.0 - 2.8) and tended to have a higher odds of death (aOR 1.6, 95%CI 0.8-3.0) than patients without HG after adjusting for potential confounders. Among the 235 patients with HG, the odds of death and ICU admission were higher in the 42 HG patients without T2D than the 193 patients with T2D (death: aOR 5.1, 95%CI 1.3 - 19.0; ICU admission: aOR 2.7, 95%CI 1.1 - 6.7) after adjusting for potential confounders including BG. HG in the subset of patients without T2D could be a marker of high inflammatory burden leading to higher mortality or undiagnosed diabetes leading to increased severity of COVID-19 due to metabolic dysfunction.

Disclosure
N. Charoenngam: None. M. F. Holick: Consultant; Self; Biogena Inc, Ontometrics Inc, Other Relationship; Self; Quest Diagnostics, Speaker’s Bureau; Self; Abbott. C. Apovian: Board Member; Self; Abbott, Allergan plc, Gelesis, Novo Nordisk, Nutrisystem, Tivity Health, Xeno Bioscience, Zafgen, Inc.

Funding
National Institutes of Health (2T32DK7201-42 to N.C.), (P30DK046200 to C.A.)
181-OR: Amino Acid-Stimulated Alpha Cell Proliferation Requires Glutaminase Activity
Authors: SIV WALTER , SELLICK KATELYN , REUTER AUSTIN , SHOU MATTHEW , STANLEY JADE , SPEARS ERICK , CHEN WENBIAO , DEAN DANIELLE 
Published: June 2021

Interrupted glucagon signaling reduces hyperglycemia. However, interrupted glucagon signaling increases serum amino acid and glucagon levels and stimulates amino acid-dependent alpha cell proliferation as part of an endocrine feedback loop, the liver-alpha cell axis. Our previous studies showed that glutamine and SLC38A5, a transporter of glutamine and other amino acids, are required for amino acid-stimulated alpha cell proliferation. To understand the mechanism of glutamine-stimulated proliferation, we analyzed published transcriptomics data for enzymes involved in the glutamine metabolism pathway and found 3-fold greater gene expression of glutaminase (Gls/GLS) in mouse and human alpha cells than in other pancreatic endocrine cells, while Gls2/GLS2 expression was extremely low in islet cells. Immunohistochemical analyses of mouse and human pancreata showed greater protein expression of GLS in islets versus the surrounding exocrine tissue. Within islets, both human and mouse alpha cells had higher expression than beta cells, suggesting that alpha cells may have increased capacity for glutamine metabolism. This expression pattern was also observed in individuals with either type 1 or type 2 diabetes. To examine the role of GLS activity in alpha cell proliferation, we treated the αTC1-6 mouse glucagonoma cell line with a competitive GLS inhibitor CB-839. GLS inhibition resulted in a 1.6-fold decrease in cell count over an 8-day cell growth assay (DMSO: (9.7 ± 1.3)x105, 10 μM CB-839: (6.2 ± 1.4)x105; n=2-4). In isolated mouse islets cultured in high glutamine and amino acid containing media, GLS inhibition inhibited alpha cell proliferation (DMSO: 7.6 ± 2.2%, 0.1 μM CB-839: 0.11 ± 0.05%**, 1.0 μM: 0.04 ± 0.02**, 10 μM: 0.02 ± 0.01%**, n=3-4, p&lt;0.01). These data indicate that glutamine metabolism through GLS is critical for amino acid-dependent alpha cell proliferation in mice and support that alpha cells are unique amino acid sensors playing a critical role in amino acid homeostasis.

Disclosure
W. Siv: None. K. Sellick: None. A. Reuter: None. M. Shou: None. J. Stanley: None. E. Spears: None. W. Chen: None. D. Dean: None.

Funding
National Institutes of Health (DK117969, DK117147, DK020593); JDRF (2-SRA-2016-149-Q-R)
185-LB: Effect of the COVID-19 Lockdown on Glycemic Control in Adult Patients with Type 2 Diabetes Mellitus
Authors: MALIK IS-HAQ O. , NAHER KAMRUN , THRUPTHI KOMANDUR , ZAIDI BUSHRA , LEUNG VIVIEN 
Published: June 2021

Objective: The rapid emergence of the SARS-COV2 virus that caused COVID-19 pandemic in early 2020 led to authorities instituting lockdown protocols to curb spread of the virus. Prior studies in patients with T1DM have demonstrated a short-term favorable or neutral effect of the lockdown on glycemic parameters; however, data is limited in T2DM patients. We sought to identify how the lockdown affected the glycemic control of adult patients with T2DM within a specific region of New York Design & Methods: In this retrospective cohort study, we analyzed data from patients with regular outpatient visits within an integrated-delivery health system in South Bronx, New York who had A1C levels measured within 6 months prior to the initiation of lockdown (Mar ’20) and a repeat A1C within 3 months after the first phase of reopening in New York (June ’20). Analysis of comparison between pre- and post-lockdown HbA1c values was performed using paired samples T-test.
Results: A total of 2489 adult patients with an established diagnosis of T2DM and A1C levels available during the study period were identified. 632 patients were excluded due to pregnancy, prediabetes, new-onset diabetes, residency in long-term care facility or hospital admission during the study period. Age range was 18 to 95 years with a mean age of 61. 58% of the patients were female and 41% male. Mean pre-lockdown A1C was 7.64% and mean post-lockdown A1C was 7.76%, indicating an increase of 0.122% (95% CI, 0.0613-0.1827)
Conclusions: The COVID-19 lockdown was associated with a small but statistically significant increase in HbA1C levels (0.122%) in a large cohort of community-dwelling adult patients with type 2 diabetes in South Bronx. Interruptions to regular outpatient care, difficulty in obtaining medications from pharmacies, changes in physical activity or diet and psychological stress related to the pandemic may have been potential contributing factors and need to be addressed to avoid further worsening of diabetes control in the longer term.

Disclosure
I. O. Malik: None. K. Naher: None. K. Thrupthi: None. B. Zaidi: None. V. Leung: None.
199-OR: Insulin Infusion Decreases Extracellular Vesicles in Adults with Metabolic Syndrome
Authors: HEISTON EMILY , BALLANTYNE ANNA , STEWART NATHAN , MUSANTE LUCA , ERDBRUEGGER UTA , MALIN STEVEN K. 
Published: June 2021

Elevated extracellular vesicles (EVs) are associated with glucose dysmetabolism. However, the direct effects of insulin on EVs and subsequent relationship with insulin sensitivity and substrate oxidation is unknown in adults with metabolic syndrome (MetS). Fifty sedentary adults (54.5 ± 1.0 yr; VO2peak: 22.3 ± 0.6 ml/kg/min) with MetS (36.3 ± 0.7 kg/m2; ATP III Criteria: 3.46 ± 1.0) underwent a 2-hr euglycemic-hyperinsulinemic clamp (90 mg/dl; 40 mU/m2/min) to determine EV responses to insulin and metabolic insulin sensitivity (M-Value). Endothelial (CD105+, CD41-/CD31+), leukocyte (CD45+), platelet (CD41+, CD41+/CD31+), and tetraspanin-derived EVs (TX+), as well as platelet endothelial cell adhesion molecule (CD31+) were detected in platelet poor plasma samples at 0 and 2-hr of the clamp using spectral flow cytometry. Fat (Fox) and carbohydrate oxidation (CHOox) were also measured (indirect calorimetry) to determine metabolic flexibility. Despite low metabolic insulin sensitivity (2.55 ± 0.2 mg/kg/min), insulin (82.9 ± 3.7 uU/ml) reduced Fox (delta, P=0.001) compared to fasting. Insulin also decreased CD105+ (P&lt;0.01), CD41-/CD31+ (P=0.03), CD41+ (trend: P=0.06), TX+ (P&lt;0.01), and CD31+ (P=0.03). Surprisingly, there were no correlations between EVs and metabolic insulin sensitivity. However, higher fasting insulin levels were related to lower insulin-stimulated changes in CD105+ (r=0.32, P=0.03), CD41-/CD31+ (r=0.33, P=0.05), and CD45+ (r=0.33, P=0.04). Further, fasting TX+ and CD41+ (r=0.33, P=0.05 and r=0.42, P&lt;0.01) were related to fasting CHOox while CD105+ was inversely associated with fasting Fox (r=-0.33, P=0.03). Fasting TX+ (r=-0.42, P=0.01), CD31+ (r=-0.33, P=0.04), and CD41+ (r=-0.32, P=0.04) also correlated with CHOox metabolic flexibility. Insulin infusion decreases EVs in adults with MetS. Additional work investigating the role of EVs on substrate metabolism is warranted to elucidate mechanisms for type 2 diabetes risk.

Disclosure
E. Heiston: None. A. Ballantyne: None. N. Stewart: None. L. Musante: None. U. Erdbruegger: None. S. K. Malin: None.

Funding
National Institutes of Health (R01HL130296)