Endocrine Function Of Pancreas Research Articles

Neuronal glucose sensing mechanisms and circuits in the control of insulin and glucagon secretion.

Glucose homeostasis is mainly under the control of the pancreatic islet hormones insulin and glucagon, which, respectively, stimulate glucose uptake and utilization by liver, fat, and muscle or glucose production by the liver. The balance between the secretion of these hormones is under the control of blood glucose concentrations. Indeed, pancreatic islet b-cells and a-cells can sense variations in glycemia and respond by an appropriate secretory response to restore euglycemia. However, the secretory activity of these cells is also under multiple additional metabolic, hormonal, and neuronal signals that combine to ensure the perfect control of glycemia over a lifetime. The central nervous system (CNS), which has an almost absolute requirement for glucose as a source of metabolic energy and, thus, a vital interest in ensuring that glycemic levels never fall below ~5mM, is equipped with populations of neurons responsive to changes in glucose concentrations. These neurons control pancreatic islet cells secretion activity in multiple ways: through both branches of the autonomic nervous system, through the hypothalamic-pituitary-adrenal axis, and by secreting vasopressin (AVP) in the blood at the level of the posterior pituitary. Here, we will present the autonomic innervation of the pancreatic islets; the mechanisms of neurons activation by a rise or a fall in glucose concentration; how current viral tracing, chemogenetic, and optogenetic techniques allow to integrate specific glucose sensing neurons in defined neuronal circuits that control endocrine pancreas function. Finally, how genetic screens in mice can untangle the diversity of the hypothalamic mechanisms controlling the response to hypoglycemia.

Differential effects of fish-oil and cocoa-butter based high-fat/high-sucrose diets on endocrine pancreas morphology and function in mice.

A high-fat/high-sucrose diet leads to adverse metabolic changes that affect insulin sensitivity, function, and secretion. The source of fat in the diet might inhibit or increase this adverse effect. Fish oil and cocoa butter are a significant part of our diets. Yet comparisons of these commonly used fat sources with high sucrose on pancreas morphology and function are not made. This study investigated the comparative effects of a fish oil-based high-fat/high-sucrose diet (Fish-HFDS) versus a cocoa butter-based high-fat/high-sucrose diet (Cocoa-HFDS) on endocrine pancreas morphology and function in mice. C57BL/6 male mice (n=12) were randomly assigned to dietary intervention either Fish-HFDS (n=6) or Cocoa-HFDS (n=6) for 22 weeks. Intraperitoneal glucose and insulin tolerance tests (IP-GTT and IP-ITT) were performed after 20-21 weeks of dietary intervention. Plasma concentrations of c-peptide, insulin, glucagon, GLP-1, and leptin were measured by Milliplex kit. Pancreatic tissues were collected for immunohistochemistry to measure islet number and composition. Tissues were multi-labelled with antibodies against insulin and glucagon, also including expression on Pdx1-positive cells. Fish-HFDS-fed mice showed significantly reduced food intake and body weight gain compared to Cocoa-HFDS-fed mice. Fish-HFDS group had lower fasting blood glucose concentration and area under the curve (AUC) for both GTT and ITT. Plasma c-peptide, insulin, glucagon, and GLP-1 concentrations were increased in the Fish-HFDS group. Interestingly, mice fed the Fish-HFDS diet displayed higher plasma leptin concentration. Histochemical analysis revealed a significant increase in endocrine pancreas β-cells and islet numbers in mice fed Fish-HFDS compared to the Cocoa-HFDS group. Taken together, these findings suggest that in a high-fat/high-sucrose dietary setting, the source of the fat, especially fish oil, can ameliorate the effect of sucrose on glucose homeostasis and endocrine pancreas morphology and function.

1431-P: Exocrine Pancreatic Insufficiency Is Both a Risk Factor for and Comorbidity of Diabetes Mellitus

Introduction: Exocrine Pancreatic Insufficiency (EPI) is an uncommon but important disease of the exocrine pancreas. Its relationship to endocrine pancreas function and diabetes (DM) remains poorly characterized. To better understand this relationship, a retrospective chart review was performed in a large statewide multispecialty practice. Methods: A retrospective review of the entire 1.3 million patient-practice of Ochsner Health system in Louisiana was performed to cover the period of January 2017 to January 2020. All cases of documented EPI and patients on pancreatic enzyme replacement therapy (PERT) were identified and underwent individual chart review to identify etiologic factors and cardiometabolic, demographic, vital sign data, and clinical course information. Results: 677 EPI patients were identified with DM being the most prevalent etiologic risk factor (44.6% T2DM, 9.6% T1DM and 11.5% secondary DM). EPI patients without DM had a 10.9% prevalence of pre-DM, and 127 new DM cases developed over the observation period among EPI patients initially without DM with an 18.7% incidence rate. EPI patients, compared to the general DM population, were significantly younger with more diverse DM etiology. They also had greater LFT and serum lipase elevations. EPI patients had lower BMIs; 25.6 ± 7.5 vs 32.8 ± 46.9 kg/m2 with greater alcohol use. EPI patients also had better glycemic control (HBAC 6.83 ± 2.1 vs 7.2 ± 1.9) and triglycerides (125.7 ± 104.7 vs 140.6 ± 118.9) though other lipids were similar. Discussion and Conclusions: EPI, though uncommon, is both an important risk factor for onset of DM and comorbidity of diabetes. DM patients with EPI have distinctive etiologic, metabolic, and anthropometric features from DM patients in the general population. Further study of EPI patients to better understand predictors of onset of EPI in DM patients and DM onset in non-DM EPI patients are needed to guide evidence based screening. This would in turn enable early EPI recognition and management. Disclosure K.G.Romo: None. S.Shu: None. A.A.Noor: None. W.A.West: None. S.Bhamre: None. G.I.Uwaifo: None.

Preclinical safety evaluation of calcineurin inhibitors delivered through an intraductal route to prevent post-ERCP pancreatitis demonstrates endocrine and systemic safety

ObjectiveThere is an urgent need for safe and targeted interventions to mitigate post-ERCP pancreatitis (PEP). Calcineurin inhibitors (CnIs) offer therapeutic promise as calcineurin signaling within acinar cells is a key initiating event in PEP. In previous proof-of-concept studies using experimental models, we showed that concurrent intra-pancreatic ductal administration of the CnIs, tacrolimus (Tac) or cyclosporine A (CsA) with the ERCP radiocontrast agent (RC) prevented PEP. To translate this finding clinically, we investigated potential toxic effects of intraductal delivery of a single-dose RC-CnI formulation on endocrine pancreas function and systemic toxicities in a preclinical PEP model. MethodsC57BL/6J mice underwent ductal cannulation and received a single, intra-pancreatic ductal infusion of RC or RC with Tac or CsA (treatment groups) or underwent ductal cannulation without infusion (‘sham’ group). To assess endocrine function, intraperitoneal glucose tolerance test (IPGTT) was performed at two days before infusion and on day 2 and 14 post-surgery. To evaluate off-target tissue toxicities, renal and hepatic function-related parameters including blood urea nitrogen, plasma creatinine, potassium, aspartate aminotransferase, alanine aminotransferase, and total bilirubin were measured at the same time-points as IPGTT. Histological and biochemical indicators of pancreas injury and inflammation were also evaluated. ResultsNo abnormalities in glucose metabolism, hepatic or renal function were observed on day 2 or 14 in mice administered with intraductal RC or RC with Tac or CsA. ConclusionIntraductal delivery of RC-CnI formulation was safe and well-tolerated with no significant acute or subacute endocrine or systemic toxicities, underscoring its clinical utility to prevent PEP.

IPSC-Derived Pancreatic Progenitors Lacking FOXA2 Reveal Alterations in miRNA Expression Targeting Key Pancreatic Genes

Recently, we reported that forkhead box A2 (FOXA2) is required for the development of human pancreatic α- and β-cells. However, whether miRNAs play a role in regulating pancreatic genes during pancreatic development in the absence of FOXA2 expression is largely unknown. Here, we aimed to capture the dysregulated miRNAs and to identify their pancreatic-specific gene targets in pancreatic progenitors (PPs) derived from wild-type induced pluripotent stem cells (WT-iPSCs) and from iPSCs lacking FOXA2 (FOXA2–/–iPSCs). To identify differentially expressed miRNAs (DEmiRs), and genes (DEGs), two different FOXA2–/–iPSC lines were differentiated into PPs. FOXA2–/– PPs showed a significant reduction in the expression of the main PP transcription factors (TFs) in comparison to WT-PPs. RNA sequencing analysis demonstrated significant reduction in the mRNA expression of genes involved in the development and function of exocrine and endocrine pancreas. Furthermore, miRNA profiling identified 107 downregulated and 111 upregulated DEmiRs in FOXA2–/– PPs compared to WT-PPs. Target prediction analysis between DEmiRs and DEGs identified 92 upregulated miRNAs, predicted to target 1498 downregulated genes in FOXA2–/– PPs. Several important pancreatic TFs essential for pancreatic development were targeted by multiple DEmiRs. Selected DEmiRs and DEGs were further validated using RT-qPCR. Our findings revealed that FOXA2 expression is crucial for pancreatic development through regulating the expression of pancreatic endocrine and exocrine genes targeted by a set of miRNAs at the pancreatic progenitor stage. These data provide novel insights of the effect of FOXA2 deficiency on miRNA-mRNA regulatory networks controlling pancreatic development and differentiation.Graphical

Assessment of exo- and endocrine function of pancreas following distal pancreatectomy

The assessment of pancreatic resection volume influence on exo- and endocrine pancreatic functions. The resected pancreatic volume influence was assessed in 47 patients: 31 (66%) patients after resections of pancreatic body and tail, and 16 (34%) patients after distal resections. The exocrine pancreatic function was assessed by pancreatic fecal elastase 1 as well as endocrine pancreatic function was assessed by C-peptide level measurement. Computed tomography with intravenous contrast enhancement and postprocessing was used for pre- and postoperative pancreatic volume assessment. All tests were performed before and 1, 3, and 6 months after surgery. Type of surgery had no influence on C-peptide and pancreatic fecal elastase 1 levels (p>0.05). Exo- and endocrine pancreatic functions markers tended to decrease in 1st month after surgery with consequent functions restoration towards 6 months after surgery. There were 15 (35.7%) patients from 42 patients with normal exocrine pancreatic function with a fecal elastase 1 level decrease to 114.7±61.8 μg/g; exocrine insuficiency remained only in 2 (4.8%) patients after 6 months after surgery. C-peptide concentration decrease before surgery to less than 1.1 ng/ml was noticed only in 8 (17%) patients. C-peptide concentration decreased in 30 (63.8%) patients in 1st month after surgery, but after 6 months after surgery, C-peptide level decrease was only in 7 (14.9%) patients. The exo- and endocrine function of the pancreas is restored in more than 80% of patients after DR. Probably it could be associated with the activation of the pancreatic compensatory abilities.

Evaluation of Serum Amylase, Lipase, Lipid Profile and Insulin levels in Smokers

ntroduction: Cigarette smoking is known to cause damage to many organs in the body. Nicotine may cause alterations in the exocrine and endocrine function of pancreas. This study aims to assess the effect of smoking on amylase, insulin levels and lipid profile in healthy smokers. Materials and Methods: 27 healthy smokers and 27 non- smokers were recruited as cases and controls. Fasting blood samples were collected for estimating the glucose, lipid profile, amylase, lipase and insulin levels. Results: There is a significant dyslipidemia, higher insulin levels and HOMA-IR and decrease in amylase and lipase levels in smokers compared to non- smokers. Conclusion: Smoking is associated with risk of development of diabetes mellitus and cardiovascular disease.

E4orf1-induced reduction in endogenous insulin level is independent of pancreas endocrine function.

Obesity is often associated with hyperinsulinemia due to insulin resistance. In mice models of hyperinsulinemia, adenovirus-derived E4orf1 protein promotes glucose disposal via insulin-independent pathway, and reduces insulin response to glucose load, described as its "Insulin Sparing Action". This is likely because less insulin is needed for disposing glucose in presence of E4orf1, however, there are other potential possibilities. This study determined if E4orf1 reduces insulin response to glucose load because it a) suppresses the ability of pancreatic β-cells to secret insulin, or b) upregulates glucagon production by the pancreas. C57BL/6J wild type (control) and transgenic C57BL/6J (E4orf1) mice that express E4orf1 protein in adipose tissue upon doxycycline feeding, were used. Post-doxycycline feeding, insulin and glucagon secretion in response to glibenclamide or phenylephrine were compared between the two groups. The pancreases were examined for histological changes. In response to glibenclamide, E4orf1 mice secreted more insulin and exhibited lower blood glucose compared to control (47.4 ± 4.4 vs 27.4 ± 3.7 mg/dl, p < 0.003), but showed no difference in glucagon secretion. Post-phenylephrine injection, no differences were observed between the two groups for glucagon or insulin, except E4orf1 mice had a lower blood glucose rise after 10-min of injection compared to the control (39.7 ± 4.7 vs. 58.3 ± 7.5 mg/dl, p < 0.05). E4orf1 mice had significantly larger pancreatic islets and higher number of islets per mm2 tissue area. Neither the size nor the number of islets met the criteria of hypertrophy or hyperplasia. E4orf1 retains and may enhance the ability of the pancreases to secret insulin in response to insulin secretagogue. Glucagon does not seem to play a role in the Insulin Sparing Action of E4orf1. Overall, the histology studies support better pancreatic islet health in presence of E4orf1, compared to that in control mice. The "insulin-independent" role of E4orf1 has potential therapeutic implications in addressing hyperinsulinemia in obesity.

Glucocorticoid Receptor Antagonist Alters Corticosterone and Receptor-sensitive mRNAs in the Hypoxic Neonatal Rat.

Hypoxia, a common stressor with preterm birth, increases morbidity and mortality associated with prematurity. Glucocorticoids (GCs) are administered to the preterm infant to improve oxygenation; prolonged use of GCs remains controversial. We evaluated a selective glucocorticoid receptor (GR) antagonist (CORT113176) in our neonatal rat model of human prematurity to assess how fasting and hypoxia-induced increases in neonatal corticosterone affects endogenous hormones and endocrine pancreas function. Neonatal rat pups at postnatal day (PD) 2, PD8, and PD15 were pretreated with CORT113176 and, after 60 minutes of separation and fasting, exposed to hypoxia (8% O2) or control (normoxia) for 30 or 60 minutes while fasting was continued. Plasma corticosterone, ACTH, glucose, and insulin were measured and fasting Homeostatic Model Assessment of Insulin Resistance was calculated. Glucocorticoid and insulin receptor-sensitive gene mRNAs were analyzed in liver, muscle, and adipose to evaluate target tissue biomarkers. CORT113176 pretreatment augmented baseline and hypoxia-induced increases in corticosterone and attenuated hypoxia-induced increases in insulin resistance at PD2. Normoxic and hypoxic stress increased the hepatic GR-sensitive gene mRNAs, Gilz and Per1; this was eliminated by pretreatment with CORT113176. CORT113176 pretreatment decreased baseline insulin receptor-sensitive gene mRNAs Akt2, Irs1, Pik3r1, and Srebp1c at PD2. We show that CORT113176 variably augments the stress-induced increases in corticosterone concentrations (attenuation of negative feedback) and that GR is critical for hepatic responses to stress in the hypoxic neonate. We also propose that measurement of Gilz and Per1 mRNA expression may be useful to evaluate the effectiveness of GR antagonism.

The risk factors of new onset diabetes mellitus following distal pancreatectomy: The ideal candidate for active surveillance

In pancreatic resection, the focus has been mainly on the oncologic safety, however, the endocrine function of the remnant pancreas also should be considered due to relatively longer life expectancy of the patients with benign or borderline malignant pancreatic tumor. We investigated risk factors for occurring new onset diabetes mellitus (NODM) after distal pancreatectomy (DP). Total 205 patients were diagnosed with benign or borderline malignant tumor of the pancreas and underwent DP from 2005 to 2019 in Severance hospital, Seoul, Korea. The patients diagnosed with NODM postoperatively under American Diabetes Association guidelines were included to DM group (n = 51), and other patients were included in non-DM group (n = 154). Preoperative characteristics and surgical outcomes were compared between two groups. We investigated risk factors for occurring NODM by univariate and multivariate analysis and analyzed cumulative NODM ratio by time sequence. Age (DM: 55.3 ± 12.3 vs. non-DM: 47.6 ± 15.2, p < 0.001) and BMI (DM: 24.1 ± 3.4 vs. non-DM: 23.0 ± 3.1, p = 0.026) were significantly higher in DM group than non-DM group. DM group showed more operation time (p = 0.033), more blood loss (p = 0.024), and more extended range of pancreatectomy (neck level resection. DM 51.0% vs. non-DM 26.6%, p = 0.002). Pathologic and postoperative outcomes did not differ between the two groups. Age over 50 (p = 0.001), pancreatectomy on neck level (p = 0.003), underline chronic pancreatitis (p = 0.039) and blood loss (p = 0.019) remained significant risk factors for NODM in multivariate analysis. About half of the NODM patients were diagnosed within 1 year postoperatively. The patients who underwent distal pancreatectomy with high risk of NODM should be actively under surveillance for at least 1 year postoperatively.

1158-P: Genetic Dissection of a Vagal Neurocircuit for Blood Glucose Regulation

Neurons of the hindbrain’s dorsal motor nucleus of the vagus (DMV) in the hindbrain control key physiological functions related to diabetes, including pancreatic hormone secretion and food passage through the GI tract. Different subtypes of DMV neurons, or “functional units,” are thought to mediate distinct physiological roles. However, a lack of definition and access to these subtypes has greatly limited what is known about them. Thus, there is much to learn about the nature of the DMV neurons controlling insulin release and gastric motility, how they function, and how they can be targeted to treat diabetes. To gain traction on this issue, we began by classifying DMV neuron subtypes based on their gene expression, using high-throughput single-nuclei RNA-seq in a mouse model. Our analysis revealed seven, molecularly-distinct subtypes of DMV neurons, two of which were respectively marked by their expression of the genes Calb2 and Grp. Fluorescence in situ hybridization revealed that Calb2 DMV neurons and Grp DMV neurons occupy different subregions of the DMV, suggesting they may innervate different parts of the digestive system. To investigate this, we stained the axons of Calb2 DMV neurons and Grp DMV neurons and imaged them in optically cleared stomach and pancreas from mouse. These studies revealed that Calb2 DMV neurons innervate pancreas but not stomach, whereas Grp DMV neurons innervate neither organ. To then determine whether Calb2 DMV neurons control pancreas endocrine function, we used intersectional optogenetics to stimulate Calb2 DMV neurons while assessing blood glucose levels in vivo. Preliminary data indicate that activating Calb2 DMV neurons causes a rapid and substantial decrease in blood glucose levels. Together our results not only identify Calb2 DMV neurons as pancreas afferents that can lower blood glucose, but reveal a “labeled line” logic to the organization of vagal motor neurons, in which genetically-distinct neuron subtypes innervate different digestive organs to control their function. Disclosure N. J. Conley: None. C. Li: None. J. Campbell: None. Funding American Diabetes Association/Pathway to Stop Diabetes (1-18-INI-14 to J.C.)

Endocrine Pancreas Development and Dysfunction Through the Lens of Single-Cell RNA-Sequencing.

A chronic inability to maintain blood glucose homeostasis leads to diabetes, which can damage multiple organs. The pancreatic islets regulate blood glucose levels through the coordinated action of islet cell-secreted hormones, with the insulin released by β-cells playing a crucial role in this process. Diabetes is caused by insufficient insulin secretion due to β-cell loss, or a pancreatic dysfunction. The restoration of a functional β-cell mass might, therefore, offer a cure. To this end, major efforts are underway to generate human β-cells de novo, in vitro, or in vivo. The efficient generation of functional β-cells requires a comprehensive knowledge of pancreas development, including the mechanisms driving cell fate decisions or endocrine cell maturation. Rapid progress in single-cell RNA sequencing (scRNA-Seq) technologies has brought a new dimension to pancreas development research. These methods can capture the transcriptomes of thousands of individual cells, including rare cell types, subtypes, and transient states. With such massive datasets, it is possible to infer the developmental trajectories of cell transitions and gene regulatory pathways. Here, we summarize recent advances in our understanding of endocrine pancreas development and function from scRNA-Seq studies on developing and adult pancreas and human endocrine differentiation models. We also discuss recent scRNA-Seq findings for the pathological pancreas in diabetes, and their implications for better treatment.

Optogenetic stimulation of cholinergic fibers for the modulation of insulin and glycemia

Previous studies have demonstrated stimulation of endocrine pancreas function by vagal nerve electrical stimulation. While this increases insulin secretion, expected concomitant reductions in circulating glucose do not occur. A complicating factor is the non-specific nature of electrical nerve stimulation. Optogenetic tools, however, provide the potential for cell-type specific neural stimulation using genetic targeting and/or spatially shaped excitation light. Here, we demonstrate light-activated stimulation of the endocrine pancreas by targeting parasympathetic (cholinergic) axons. In a mouse model expressing ChannelRhodopsin2 (ChR2) in cholinergic cells, serum insulin and glucose were measured in response to (1) ultrasound image-guided optical stimulation of axon terminals in the pancreas or (2) optical stimulation of axons of the cervical vagus nerve. Measurements were made in basal-glucose and glucose-stimulated conditions. Significant increases in plasma insulin occurred relative to controls under both pancreas and cervical vagal stimulation, while a rapid reduction in glycemic levels were observed under pancreatic stimulation. Additionally, ultrasound-based measurements of blood flow in the pancreas were increased under pancreatic stimulation. Together, these results demonstrate the utility of in-vivo optogenetics for studying the neural regulation of endocrine pancreas function and suggest its therapeutic potential for the control of insulin secretion and glucose homeostasis.

Insight into the exocrine pancreatic function (serum amylase and lipase) in type 2 diabetes mellitus

Introduction: Insulin has its effect on the basal and stimulatory secretion of exocrine pancreatic enzymes. In this context this study has been done to understand the relationship between the exocrine and endocrine entities of pancreas by analyzing two most commonly estimated exocrine enzymes; serum amylase and serum lipase in type 2 DM. Materials and Methods: The study was conducted at Rajarajeswari Medical College and Hospital, Bengaluru, Karnataka from January 2012 to December 2012. Hundred clinically diagnosed cases of type 2 diabetes mellitus {Fifty well controlled (HbA1c < 7> Results: Serum amylase and serum lipase levels were within the reference range in all the three study groups. There was no significant difference in serum amylase among well controlled and poorly controlled type 2 DM. In contrast, significant difference in serum amylase levels was observed between diabetic group and controls (p Conclusion: The potential underlying connection between exocrine and endocrine function of pancreas in patients with type 2 DM needs further investigation with larger population; to consider the analysis of serum pancreatic enzymes especially serum lipase levels as an additional informative parameter to assess the glycemic control in type 2 DM. Keywords: Type 2 DM, Serum amylase, Serum lipase.

147-OR: Long-Term Effect of GLP-1 on Pancreas Endocrine Function after Gastric Bypass in Individuals with and without Diabetes Remission

The contribution of GLP-1 on glucose control after gastric bypass (GBP) is not fully elucidated. Hypotheses: The improvement in β-cell glucose sensitivity (BCGS) to oral glucose after GBP is GLP-1 mediated, weight loss independent, and varies according to diabetes (T2D) remission status; The administration of exendin 9-39 (EX9), a GLP-1 receptor blocker, has minimal effect on blood glucose. Methods: Patients with T2D (n=29) underwent a 75 g OGTT prior to and at 3, 12 and 24 months (M) after GBP. Glucose, insulin secretion rates (ISR), BCGS, and glucagon were measured with and without EX9. The cohort was retrospectively divided into 3 groups based on T2D remission status determined at the latest study time point (24 or 12M): remitters (REM, n=5), persistent T2D (P-T2D, n=8), impaired (IGT, n=16). Results: Prior to GBP, patients were 42.9±8.3y old, had a BMI of 42.4±4.6 kg/m2, 7.7±7.3 y known T2D duration, an HbA1c of 7.8±1.1% (35% on insulin) and an HOMA-IR of 11.5±5.8. Both magnitude and temporal increases in BCGS varied according to remission status: greater (up to 6.5 fold, p&amp;lt;0.03) and sustained in REM, variable in IGT (∼3 fold, p&amp;lt;0.01), minimal and only transient (3M, p=0.014) in P-T2D. These differences were not explained by weight-loss since it did not differ between the 3 groups at any time. EX9 reversed the effect of GBP on ISR at 3, 12 and 24M (p&amp;lt;0.003); it further enhanced the rise in post-prandial glucagon, but this effect was only significant at 3M (p=0.005). Both effects varied in magnitude overtime and by remission status. Glucose improved after GBP, as expected; EX9 decreased glucose levels at 3M in the whole cohort (p&amp;lt;0.001), but had no effect on glucose at 12 and 24M. EX9 increased significantly, albeit minimally, glucose at 120 and/or 180 minutes during the OGTT in REM and IGT, but not in P-T2D. Conclusions: Our data suggest that the effect of endogenous GLP-1 on pancreatic endocrine function and glucose varies with time and according to remission status after GBP. Disclosure M.A. Prasad: None. A. Shah: None. V.M. Mark: None. N. Nair: None. J.J. Holst: Advisory Panel; Self; AstraZeneca, Merck Sharp &amp; Dohme Corp., Novo Nordisk A/S, Zealand Pharma A/S. Other Relationship; Spouse/Partner; Antag Therapeutics. Funding National Institutes of Health (R01DK67561, DK007559, P30DK26687, UL1RR024156, UL1TR000040, F32DK113747)

248-LB: Spexin Promotes Insulin Secretion and ß-Cell Proliferation

Spexin was firstly discovered as a neuropeptide and was also detected in peripheral tissues including liver, fat and pancreatic islets. Recently, studies documents that diabetes patients had lower circulation level of Spexin. It is unclear whether Spexin exerts glucose homeostasis regulating effects. Here, we provide evidence that Spexin stimulates β cell proliferation and insulin secretion in mice and human islets. Acute administration of Spexin prior glucose challenge promoted insulin secretion and improved glucose tolerance in a dose dependent manner (35-200 μg/kg BW). Meanwhile, Spexin treatment had no effect on insulin tolerance. The addition of Spexin to mouse islets increased β cell proliferation demonstrated by 2-fold increase of BrdU(+) β-cells. Spexin promoted cell growth of INS-1 cells in a dose dependent manner with maximum effect at dose of 25 ng/ml. In a high-fat diet (HFD)-induced β cell proliferation and β cell mass expansion model, the percentage of Ki67(+) β-cells increased by 2-fold compared to chow diet (CD)-fed mice. Spexin provoked further 80% increase. Consistently, HFD feeding increased β-cell mass by 2-fold and Spexin made further 58% increase. To identify the mechanism of Spexin-stimulated β cell proliferation, we tested whether the expression of well-established β cell cycle regulators was controlled by Spexin. Spexin treatment of INS-1 cells for 24 h significantly increased mRNA levels of cyclin D1 and Cyclin E1 compared with controls. Spexin stimulated the phosphorylation of CREB (p-CREB) with a peak at 10 min. The addition of H89, a potent PKA inhibitor blocked the effect of Spexin on activation of p-CREB and stimulation of the expression of Ki67, Cyclin D1 and Cyclin E1. Furthermore, Spexin stimulated the p-CREB, promoted insulin secretion and increased β cell proliferation in human islets. Thus, Spexin is an important factor for islet β cell proliferation, and our study provides previously unrecognized evidence of a factor governing endocrine pancreas growth and function. Disclosure R. Liu: None. Funding National Natural Science Foundation of China (81200622, 81570518, 81630020)

Maternal hypothyroidism in mice influences glucose metabolism in adult offspring

Aims/hypothesisDuring pregnancy, maternal metabolic disease and hormonal imbalance may alter fetal beta cell development and/or proliferation, thus leading to an increased risk for developing type 2 diabetes in adulthood. Although thyroid hormones play an important role in fetal endocrine pancreas development, the impact of maternal hypothyroidism on glucose homeostasis in adult offspring remains poorly understood.MethodsWe investigated this using a mouse model of hypothyroidism, induced by administration of an iodine-deficient diet supplemented with propylthiouracil during gestation.ResultsHere, we show that, when fed normal chow, adult mice born to hypothyroid mothers were more glucose-tolerant due to beta cell hyperproliferation (two- to threefold increase in Ki67-positive beta cells) and increased insulin sensitivity. However, following 8 weeks of high-fat feeding, these offspring gained 20% more body weight, became profoundly hyperinsulinaemic (with a 50% increase in fasting insulin concentration), insulin-resistant and glucose-intolerant compared with controls from euthyroid mothers. Furthermore, altered glucose metabolism was maintained in a second generation of animals.Conclusions/interpretationTherefore, gestational hypothyroidism induces long-term alterations in endocrine pancreas function, which may have implications for type 2 diabetes prevention in affected individuals.

SUN-LB90 Taurine Reverses Protein Malnutrition-Induced Endothelial Dysfunction of Pancreatic Vasculature

Background: Pancreatic islets are highly vascularized and there is a correlation between endocrine pancreas function and pancreas perfusion. Protein malnutrition during early stages of development predispose to cardiovascular diseases, impaired insulin secretion and, type 2 diabetes. However, it is unknown if there are alterations in the pancreatic vasculature in response to malnutrition. Taurine (TAU) supplementation has been suggested as antihypertensive and improves endothelial function and insulin secretion in cardiometabolic disorders. Here, we investigated the effect of TAU in the vasorelaxation and endothelium-derived factors of the lieno-pancreatic artery from protein malnourished mice. Because lieno-pancreatic artery provides blood supply to pancreatic splenic lobe, a protective effect of TAU may result in cardiometabolic benefits. Methods: Post-weaned male C57Bl/6 mice fed a normal- (14%, NP) or a low-protein (6%, LP) diet for 90 days. Concomitantly, half of LP mice received 2.5% TAU in drinking water. Lieno-pancreatic artery (internal diameter ~ 160 µm) was isolated and concentration-response relaxation curves to acetylcholine (ACh), nitric oxide (NO)-donor (SNP), or hydrogen sulfide (H2S)-donor (NaHS) were performed. The involvement of NO and endothelium-derived hyperpolarization (EDH) in ACh-induced relaxation was assessed using L-NAME (NO synthase inhibitor) or KCl (to attenuate K+ efflux), respectively. Protein expression was evaluated by Western-blot; NO and H2S production by DAF-2A and WSP-1 fluorescence, respectively. Results: Endothelium-dependent relaxation to ACh was reduced in lieno-pancreatic artery from LP compared with NP group. Either KCl or L-NAME reduced ACh-induced relaxation, but only KCl abolished differences between LP and NP, suggesting that EDH rather than NO is involved in the impaired endothelium-dependent relaxation of LP. In accordance, relaxation to SNP, NO production, and endothelial NO synthase (eNOS) expression were not altered in lieno-pancreatic artery of LP group compared to NP. Because H2S has been demonstrated to have EDH activity in several blood vessels we investigated this pathway. H2S production and NaHS-induced relaxation were both reduced in lieno-pancreatic artery of LP group compared with NP. TAU treatment reversed the impaired relaxation to ACh and to NaHS, as well as significantly increased H2S production in lieno-pancreatic artery of LP group. Conclusion: Protein malnutrition resulted in endothelial dysfunction of lieno-pancreatic artery associated with an impaired production and relaxation to H2S, which was restored by TAU. Therefore, beneficial effects of TAU on lieno-pancreatic artery vasodilatory function may result in improved pancreatic islet blood flow highlighting the potential of TAU for vasculo-metabolic protection.Funding: FAPESP, CAPES.

Management of multi-relapsed chronic pancreatitis through Rasaushadhis: A case study

Chronic pancreatitis is the long-standing inflammation of the pancreas, leading to irreversible damage of the gland. The disease is characterized by loss of exocrine and endocrine functions of pancreas owing to fibrosis and parenchymal damage. Clinical manifestations of the disease include abdominal pain, episodes of acute pancreatitis, nausea, vomiting, steatorrhea, indigestion, weight loss, and uncontrolled blood sugar. No authentic tools have yet been identified to predict the course of the disease, frequency of acute exacerbations, and rate of disease progression. Pancreatic enzymes, supplements, and a low-fat diet are usually prescribed to patients of pancreatitis. However, patients continue to experience unpredicted flare up of symptoms that are managed by IV fluids, antibiotics, and painkillers in case of acute exacerbations. Surgical intervention and stenting might also be done in some cases to bring relief to patients. However, these have limited effect, and the disease continues to progress and causes pancreatic cancer and casualties as well. Despite advances in medical science, the prognosis of the disease remains variable and unclear. Studies indicate a mortality rate of 17% in 5 years, 30% in 10 years, and 55% in 20 years after the diagnosis of chronic pancreatitis. Here, a case of chronic pancreatitis that was treated in lines of Ayurveda is presented. The patient has not suffered any attack after the commencement of Ayurvedic treatment and completes nine years of symptom-free status with no signs of progression in radiological tests.

329-LB: Exocrine Pancreas Proteases Are Drivers of ß-Cell Proliferation

The clinical link between loss of β-cell mass and diabetes susceptibility provides a promising avenue of research for novel therapeutics targeting the proliferative axis. To identify potential new pathways involved we utilized two zebrafish genetic models Alström Syndrome (AS) and Bardet-Biedl Syndrome (BBS) that exhibit strikingly different diabetes rates, ∼75% in AS and ∼4% in BBS. We have previously shown β-cell loss in AS and increase in BBS, corresponding to their diabetes rates. RNA-Sequencing of these models identified several exocrine pancreas proteases that were differentially expressed between AS and BBS. Thus, we hypothesized that the exocrine pancreas proteases affect endocrine pancreas function. To test our hypothesis, we overexpressed each enzyme in transgenic zebrafish embryos in which β-cells can be visualized. In control animals, overexpression of exocrine pancreas proteases significantly increased the β-cell number. Overexpression rescued the loss of β-cells observed in animals depleted of alms1. We found ctrb1 overexpression led to increased β-cell proliferation in transgenic larvae and rescued the AS model reduction in proliferation. To test for endogenous protease uptake, we generated a transgenic GFP-tagged CTRB1 and found that 10% of β-cells were GFP+, suggesting a direct interaction between the exocrine and endocrine pancreas. We also found that the inactive, zymogen, form of these enzymes are taken up by β-cells in vitro and induce proliferation in cultured MIN6 β-cells and freshly isolated ex vivo islet cultures, suggesting this effect is conserved in mammalian systems. These data support an important role for exocrine pancreatic enzymes in the modulation of β-cells in diabetes. Disclosure T.L. Hostelley: None. J. Dunleavey: None. E.J. Larkin: None. A.J. Jones: None. D.L. Boyes: None. M.J. Fontaine: None. N.A. Zaghloul: None. Funding National Institutes of Health (F31DK115179-01A1, T32DK098107, R01DK102001, R25GM055036)