bluuebunny/crossref_metadata_2025_split huggingface dataset:
175-LB: Altered Glycogen Cell Number in Placental mTOR Signaling Deficiency Model in Mice
Authors: CLIFTON BRIANA , BEETCH MEGAN , ALEJANDRO EMILYN 
Published: June 2023

Fetal Growth Restriction (FGR) is a determinant for the development of chronic diseases, such as type II diabetes in adulthood. FGR is caused by the failure of the placenta to provide adequate nutrients and oxygen for fetal development. mTOR regulates cell metabolism and growth, and it is reduced in the FGR placenta. We previously reported that placental mTOR ablation induces insulin resistance and glucose intolerance in adult mice. We hypothesize that mTOR signaling regulates glucose utilization in the placenta, which stores glucose reservoirs as glycogen. Appropriate localization and breakdown of glycogen cells is crucial for normal fetal growth. We leveraged our mouse model lacking placental mTOR signaling to ask whether glycogen cell number was altered. First, we found that critical glycogenesis and glycogenolysis enzymes, as well as the glucagon receptor, were expressed in placental tissue, indicating the capability for glycogen cell synthesis and breakdown, like glycogen-rich tissues such as the liver. Next, we show increased glycogen cell counts in the junctional zone of the mTORKO placenta compared to littermate controls by IHC. However, whole placental glycogen content, measured by ELISA, demonstrates no changes between KO and control. These data suggest that mTOR signaling modulates the localization and migration of glycogen cells during high metabolic needs. Glucagon mRNA is expressed in the placenta, with significant increases in the male KO placenta, indicating the placenta may produce its own glucagon. However, IHC staining indicates increased glucagon levels in female KO placenta in the labyrinth zone. Together, these data suggest that the placenta may have the capability to regulate its own glycogen breakdown by altering glucagon expression. Our results indicate that the FGR placenta induced by mTOR deletion has altered glycogen cell content and mislocalization, which mimics the phenotypes of placenta impacted by gestational diabetes, suggesting a shared mechanistic pathway.

Disclosure
B. Clifton: None. M. Beetch: None. E. Alejandro: None.

Funding
National Institutes of Health (R01DK115720)
175-OR: Pregnancy Intervention with a Closed-Loop System (PICLS) Study
Authors: BUSCHUR ELIZABETH , SNELL-BERGEON JANET K. , PYLE LAURA , GARCETTI RACHEL , DUNGAN KATHLEEN M. , THUNG STEPHEN F. , BARTHOLOMEW ANNA , SUMMERFIELD TARYN , BLOKS TANNER , NEASE EMILY R. , POLSKY SARIT 
Published: June 2023

We performed a parallel, two-site, randomized controlled trial of a commercially available hybrid closed-loop (HCL) system compared to sensor augmented pump therapy (SAPT) in pregnant women with type 1 diabetes (T1D). Participants started SAPT (Medtronic 670G) by 11 weeks gestation, were randomized at 14-18 weeks, and continued therapy until 6 weeks postpartum. The HCL group used assistive techniques, “fake carbohydrate” boluses, to optimize therapy. We performed linear mixed model regression to compare outcomes between groups, adjusted for clinic. There were 24 women randomized and 23 completers. At baseline there were no significant differences between groups (mean baseline A1C 6.8% at 8w5d [SAPT]/9w0d [HCL] enrollment). There were no episodes of severe hypoglycemia or diabetic ketoacidosis after randomization. Adverse skin reactions occurred in 6 participants (5 SAPT vs 1 HCL, p=0.1550) with a median (IQR) number of 1 (1-2) SAPT vs 4 (4-4) HCL (p=0.8774). A1C significantly decreased from baseline to 2nd trimester, and was different between groups in the 3rd trimester (Table 1). There were no differences in time below, within, or above range between groups during the study (Table 1) or in gestational health outcomes (Table 2). In a pilot cohort of pregnant women with T1D, assisted HCL therapy did not increase risk to mothers or fetuses compared to SAPT despite lack of a pregnancy-specific algorithm in the HCL system.

Disclosure
E.Buschur: Consultant; Beta Bionics, Inc., Research Support; Dexcom, Inc., JDRF, Leona M. and Harry B. Helmsley Charitable Trust. E.R.Nease: None. S.Polsky: Other Relationship; diaTribe, Research Support; Dexcom, Inc., Medtronic, Hemsley Charitable Trust, JDRF, NIH - National Institutes of Health. J.K.Snell-bergeon: None. L.Pyle: None. R.Garcetti: None. K.M.Dungan: Board Member; Elsevier, Consultant; Eli Lilly and Company, Dexcom, Inc., Other Relationship; UpToDate, Research Support; Dexcom, Inc., Abbott, ViaCyte, Inc., Sanofi, Speaker's Bureau; Academy for Continued Healthcare Learning, Cardiometabolic Health Congress, Medscape, Integritas. S.F.Thung: None. A.Bartholomew: None. T.Summerfield: None. T.Bloks: None.

Funding
JDRF (2-SRA-2018-666-M-R); Colorado Clinical and Translational Sciences Institute; Children’s Diabetes Foundation; National Center for Research Resources (UL1RR02578)
1756-P: Extracellular Matrix Stiffness Mediates Insulin Secretion in Pancreatic Islets via Phosphofructokinase Activity
Authors: GARCIA CHELSEA , HOLCOMB KEIFER , FARNSWORTH NIKKI L. 
Published: June 2023

Pancreatic islets are surrounded by extracellular matrix (ECM) which provides mechanical and biochemical cues to the β-cells that regulate survival and insulin secretion. Changes to ECM stiffness have been correlated to dysfunction in insulin secretion that is directly coupled to glucose metabolism; however, the mechanisms of mechanotransduction regulating insulin secretion have not been studied in the islet. We hypothesize that increasing matrix stiffness will increase islet glucose sensitivity by increasing phosphofructokinase (PFK) activity. To determine the effect of changes in ECM stiffness on islet function we encapsulated mouse islets in a reverse thermal gel (RTG) scaffold with increasing stiffness as determined by rheological analysis. Glucose-stimulated insulin secretion, PFK activity, and PFK expression was measured after 24 hours of culture. Proliferation was analyzed by immunohistochemistry of Ki-67. Reactive oxygen species (ROS) were measured via confocal microscopy of islets transfected with an adenoviral ROS sensor. We found that increasing RTG wt% yielded increasing stiffness at 40°C. Insulin secretion increased as the matrix stiffness increased in basal (2mM) and high glucose (20mM) conditions. Insulin secretion at 20mM glucose normalized to 2mM glucose (stimulation index) decreases with matrix stiffness indicating dysfunction to insulin secretion. PFK activity increased in islets encapsulated in stiffer RTGs. No changes in proliferation were observed in any samples compared to controls. Our results support a role for ECM stiffness in regulating insulin secretion via PFK activity. This work provides insight into how changes in ECM stiffness contribute to islet dysfunction, as in pancreatitis and T2D. Our results will inform future development of mechanically tuned microenvironments for differentiation of iPSCs into functional β-cells and provide novel targets to protect against islet dysfunction in T2D.

Disclosure
C.Garcia: None. K.Holcomb: None. N.L.Farnsworth: None.

Funding
American Diabetes Association (7-21-JDF-020 to N.L.F.); National Institutes of Health (1F31DK132926-01A1); JDRF (3-APF-2019-749-A-N, 1-FAC-2020-891-A-N)
1774-P: Verapamil Prevents Decline of IGF-1 in Subjects with T1D
Authors: XU GUANLAN , CHEN JUNQIN , LU BRIAN , QIAN WEIJUN , SHALEV ANATH 
Published: June 2023

We have previously found that the calcium channel blocker and anti-hypertensive, verapamil, promotes functional beta cell mass and improves glucose homeostasis in diabetic mice and in humans with recent-onset type 1 diabetes (T1D). Surprisingly, we also discovered that verapamil reversed the T1D-associated elevation in T-follicular-helper cell markers in peripheral blood monocytes, suggesting that it also has immunomodulatory effects. Now, a global proteomics analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) of serum samples from T1D subjects at baseline and after 1 year of receiving verapamil or placebo identified insulin-like growth factor 1 (IGF-1) as one of the top proteins with significantly changed abundance over time. Specifically, IGF-1 abundance decreased during year 1 after diagnosis in subjects with T1D receiving placebo, which is consistent with the lower IGF-1 levels reported previously in individuals with T1D as compared to age- and sex-matched healthy subjects. Interestingly, this decline was blunted in subjects receiving verapamil. To further confirm the LC-MS/MS results, we also measured patient serum levels of IGF-1 by ELISA. The results were very much in alignment and again revealed significantly decreased IGF-1 levels in the placebo group a year after diagnosis, but no such effect in the verapamil treatment group, suggesting that verapamil prevents the decline of IGF-1 in subjects with T1D. Of note, IGF-1, which is primarily produced in liver, acts on many tissues, including pancreatic islets promoting pathways involved in cell growth, differentiation and glucose metabolism. In beta cells, IGF-1 has also been shown to control apoptosis. Thus, our results reveal yet another previously unappreciated pathway affected by verapamil that may contribute to the beneficial effects observed with this treatment in the context of T1D.

Disclosure
G.Xu: None. J.Chen: None. B.Lu: None. W.Qian: None. A.Shalev: Other Relationship; TIXiMED.

Funding
National Institutes of Health (R01DK078752, U01DK120379)
1776-P: Glucolipotoxic Conditions Affect Membrane Potential Wave Velocity Determined in Intact Islets Using Microelectrode Arrays
Authors: GRESCH ANNE K. , DEICKERT THOMAS , HÜWEL JAN D. , BRIGGS JENNIFER , BEECKS CHRISTIAN , BENNINGER RICHARD K. , DÜFER MARTINA 
Published: June 2023

Pancreatic β-cells form highly connected networks within pancreatic islets. Each cell shows upon stimulation an oscillatory depolarization of the membrane potential and subsequent changes in [Ca2+]c. These signals propagate through the islet. The extent to which this coordinated islet cell activity is determined by a subset of β-cells is currently under discussion. In order to determine factors that influence this propagation, we have chosen a new method to identify wave propagation. We used high-resolution microelectrode arrays (CMOS-MEA) to measure voltage changes in the membrane potential of islet cells within the intact mouse islet. For network analysis, the individual electrode traces were compared with each other to gain insight into connectivity. The node degree of an islet (treated with 10 mM glucose) appears to be higher in the middle, but on average it was 8±2 degrees. Furthermore, algorithms were established to track the wave propagation from electrode to electrode, i.e. approximately from cell to cell. Treatment of isolated islets from C57BL6 mice with increasing glucose concentrations revealed that 15 mM glucose significantly reduced the wave duration compared to 6, 8 and 10 mM glucose (6 mM glucose: 10±4 s, n=32, vs. 15 mM glucose 7±2 s, n=26, p=0.0007). Additionally, the wave velocity was increased with rising glucose concentrations (6 mM glucose: 72±33 µm/s, n=20, vs. 8 mM glucose 118±69 µm/s, n=25, p=0.009). However, when the islets were pre-incubated with glucolipotoxic medium (25 mM glucose, 100 µM palmitate) for 72 h to mimic pre-diabetic conditions the wave velocity (waves induced by 8 mM glucose) was reduced (control: 87±40 µm/s, n=19, vs. GLT 64±32 µm/s, n=25, p=0.04). The results show that propagating waves of membrane depolarization are likely an important aspect for a functioning islet. The established technique proves to be suitable for tracking signal propagation and opens a wide field for further studies on islet network signaling.

Disclosure
A.K.Gresch: None. T.Deickert: None. J.D.Hüwel: None. J.Briggs: None. C.Beecks: None. R.K.Benninger: None. M.Düfer: None.

Funding
National Institute of Diabetes and Digestive and Kidney Diseases (R01DK102950R01, DK106412)
1779-P: Lipotoxicity-Induced Beta-Cell Small Extracellular Vesicles Promote Beta-Cell Functional Failure through Activation of the TGFß/Smad3 Pathway
Authors: ROY ABHISHEK , HOFF ALEXANDRA , HER TRACY K. , SANKARAN RAJAGOPALAN KAMALNATH , MALTAIS DANIELA D. , MATVEYENKO ALEKSEY , JAVEED NAUREEN 
Published: June 2023

Lipotoxicity is a pathological process that occurs in several metabolic disorders including obesity-driven Type 2 diabetes (T2D). Chronically elevated circulating free fatty acids have been shown to exert detrimental effects on pancreatic islet β-cells through reduced glucose-stimulated insulin secretion (GSIS), alterations in β-cell transcriptional identity, and apoptosis. β-cell-derived small extracellular vesicles (sEV) have been shown to contribute to β-cell failure in T2D, however their role in lipotoxicity-mediated β-cell failure has yet to be elucidated. We hypothesize that lipotoxicity-induced β-cell functional failure is mediated in part by aberrant release of altered β-cell-derived sEV. To test this, MIN6 β-cells were exposed to free fatty acid, palmitate (PAL) (0.5 mM, 24h) and EV were isolated using differential ultracentrifugation to yield PAL EV (vs. control (CTL) EV). β-cell functional assessment using GSIS on mouse islets exposed to PAL EV (48h) resulted in significant suppression of GSIS (~80% decrease in stimulation index). RNA-Seq was conducted on islets exposed to PAL EV (vs. untreated (UT)). De novo motif analysis from this data identified enriched transcription factor binding motifs associated with several SMAD genes in TGFβ signaling. Gene Set Enrichment Analysis revealed significant enrichment of genes associated with TGFβ receptor binding suggesting its potential role in lipotoxic β-cell EV-mediated β-cell failure. To confirm, analysis of p-Smad3 expression was conducted by immunofluorescence staining on mouse islets exposed to PAL EV (48h; vs. UT). The results showed an ~60-fold increase in β-cell p-Smad3 expression (p&lt;.05). Moreover, mouse islets were treated with a TGFβ receptor inhibitor in the presence of PAL EV (48h; vs. UT). GSIS results showed a significant improvement in β-cell function (p&lt;.05) suggesting the role of the TGFβ/Smad3 pathway in lipotoxic β-cell sEV induced β-cell failure.

Disclosure
A.Roy: None. A.Hoff: None. T.K.Her: None. K.Sankaran rajagopalan: None. D.D.Maltais: None. A.Matveyenko: None. N.Javeed: None.

Funding
National Institute of Diabetes and Digestive and Kidney Diseases (DK129208-01); JDRF (2-SRA-2022-1272-S-B)
1780-P: Assessment of Toll-Like Receptor Expression and Signaling in Islets under Metabolic and Inflammatory Conditions
Authors: MATTKE JORDAN D. , NAZIRUDDIN BASHOO , LAWRENCE MICHAEL C. 
Published: June 2023

Pancreatic beta cells undergoing metabolic and inflammatory stress express islet-derived cytokines or “isletokines” which can induce immune cell infiltration and cellular damage leading to loss of islet cell function. We and others have shown that toll-like receptor (TLR) 4 in islets can mediate metabolic and inflammatory response to DAMPs under diabetic conditions and in islet cell transplantation. Here we show that metabolic and inflammatory conditions result in induction and suppression of expression of multiple members of the TLR family in both MIN6 beta-cell line and mouse islets. Among upregulated TLRs, the endosomal nucleic acid-sensing TLR3 was most highly induced (up to 5 fold) in response to cytokine cocktail IL-1beta, TNF-alpha, and IFN-gamma in the presence of high glucose. Induction of TLR3 expression was blocked by PI3 kinase inhibitor wortmannin and unaffected by mTOR inhibitor rampamycin, calcineurin inhibitor FK506, and NF-κB inhibitor BMS345541. Immunoblot analyses confirmed that TLR3 but not TLR4 protein expression was wortmannin sensitive. These data indicate that TLR3 is upregulated by PI3 kinase signaling in islet beta cells in response to inflammatory conditions. As the endosomal TLR3 signaling is known to sense nucleic acids as well as influence glucose homeostasis, we propose that beta cells may sense DNA damage to induce isletokines to mediate local inflammatory responses during metabolic and inflammatory stress. Further investigations are warranted to decipher signaling pathways and molecular targets of TLR3 signaling to alleviate islet inflammation and improve beta-cell function.

Disclosure
J.D.Mattke: None. B.Naziruddin: None. M.C.Lawrence: None.
180-LB: Associations of Phthalate Metabolites with Glycemic Parameters and Fetal Growth in Type 1 Diabetes (T1D) Pregnancies
Authors: PRESTON EMMA V. , HANSBURY GEORGIA A. , O'CONNELL JULIANNE C. , WOLFS DANIELLE , DREYFUSS JONATHAN , WOLPOWITZ SHIRA , WANG ZIFAN , JAMES-TODD TAMARRA , ISGANAITIS ELVIRA M. , BROWN FLORENCE M. 
Published: June 2023

Background: The risk of delivering a large for gestational age (LGA) infant is higher in pregnant individuals with T1D compared to individuals without diabetes, despite advances in managing T1D in pregnancy. Exposure to endocrine disrupting chemicals (e.g., phthalates) can affect both glucose homeostasis and fetal growth.
Objective: To estimate associations of urinary phthalate metabolite levels with continuous glucose monitoring (CGM) data in pregnancy and birthweight.
Methods: We analyzed urinary levels of 14 phthalate metabolites and derived trimester-specific CGM summary measures in 32 pregnant women with T1D. We estimated associations of log2-transformed urinary metabolite levels with continuous CGM outcomes and infant weight (GROW percentile) using linear regression, and estimated associations between metabolite levels and odds of LGA (GROW percentile ≥90) vs. AGA (&lt;90) using logistic regression. Models were adjusted for maternal age and gestational week of study visit.
Results: Participants were primarily white (85%), nulliparous (53%), with a mean age of 33 years, and 50% had LGA infants. Concentrations of mono-benzyl phthalate (mBzP) and mono-carboxy octyl phthalate (mCNP), were associated with glycemia in the 3rd trimester. Specifically, each doubling of mBzP and mCNP concentration was associated with 8.5 mg/dL (95% CI: 1.4, 15.6) and 8.9 mg/dL (-1.3, 19.0) higher average glucose, -6.0% (-10.9, -1.0) and -8.9% (-15.1, -2.7) less time spent in range (63-140mg/dL), and 5.9% (0.7, 11.2) and 7.4% (0.3, 14.5) more time spent above range (&gt;140 mg/dL). Phthalates were not associated with continuous GROW percentile.
Conclusion: Exposure to certain phthalates in later pregnancy may affect glycemic control in pregnant individuals with T1D. However, effects of phthalate exposure on birthweight are unclear. Future studies may disentangle the extent to which phthalate exposure and its effects on glycemic control may impact fetal growth.

Disclosure
E. V. Preston: None. F. M. Brown: Other Relationship; Dexcom, Inc. G. A. Hansbury: None. J. C. O'connell: None. D. Wolfs: None. J. Dreyfuss: None. S. Wolpowitz: None. Z. Wang: None. T. James-todd: None. E. M. Isganaitis: None.

Funding
National Institute of Environmental Health Sciences; National Institute of Diabetes and Digestive and Kidney Diseases
180-OR: Baseline Predictors of Remission of Type 2 Diabetes in Response to Short-Term Insulin-Based Therapy—The Pivotal Role of Beta-Cell Function
Authors: RETNAKARAN RAVI , PU JIAJIE , EMERY ALEXANDRA , KRAMER CAROLINE K. , ZINMAN BERNARD 
Published: June 2023

Short-term treatment with insulin can induce remission of type 2 diabetes (T2DM) in some patients but not others. We thus sought to identify baseline predictors of diabetes remission in response to short-term insulin-based therapy. In this study, adult patients with T2DM of &lt;7 years duration were randomized to 8-weeks treatment with (i) insulin glargine, (ii) glargine + thrice-daily lispro, or (iii) glargine + twice-daily exenatide, followed by 12-weeks washout that enabled assessment of remission (defined as A1c&lt;6.5% after ≥3 months without glucose-lowering therapy). At baseline, 8-weeks, and washout, beta-cell function was assessed with 4 measures: Insulin Secretion-Sensitivity Index-2 (ISSI-2), insulinogenic index/HOMA-IR, ΔCpeptide0-120/Δglucose0-120×Matsuda, and ΔISR0-120/Δgluc0-120×Matsuda. Diabetes remission was achieved in 31 of 90 participants (34.4%). Compared to their peers, those who went on to remission had lower A1c (p&lt;0.001) and better beta-cell function at baseline (all 4 measures p≤0.01). The non-remission and remission groups did not otherwise differ in baseline insulin sensitivity/resistance (Matsuda, HOMA-IR), BMI, duration of diabetes, pre-trial diabetes medications, or allocated insulin-based therapy during the trial. On logistic regression analyses, each baseline measure of beta-cell function emerged as a significant predictor of remission (log ISSI-2: adjusted OR 4.41 (95%CI: 1.71-11.34); log insulinogenic index/HOMA-IR: 2.21 (1.26-3.89); log ΔCpeptide0-120/Δglucose0-120×Matsuda: 1.62 (1.00-2.64); log ΔISR0-120/Δgluc0-120×Matsuda: 1.87 (1.09-3.23). Similarly, higher baseline ISSI-2 tertile predicted longer time to glycemic relapse after cessation of the insulin-based therapy (log-rank P=0.029). In conclusion, beta-cell function is the dominant baseline determinant of the likelihood of achieving remission of diabetes in response to short-term insulin-based therapy.

Disclosure
R.Retnakaran: Other Relationship; Sanofi, Eli Lilly and Company, Research Support; Boehringer Ingelheim/Mount Sinai Hospital, Novo Nordisk. J.Pu: None. A.Emery: None. C.K.Kramer: Research Support; Boehringer Ingelheim Inc. B.Zinman: Consultant; Abbott Diabetes, Eli Lilly and Company, Novo Nordisk A/S, Novo Nordisk Canada Inc., Boehringer Ingelheim Inc., Merck & Co., Inc.

Funding
Canadian Institutes of Health Research (MOP136938)