Islet Area Research Articles

High-casein diet restores the redox balance in the liver and pancreatic health of mice when exposed to radiation during call mode from mobile phones

Introduction: The current lives of human beings cannot be imagined without cellular phones and electronic gadgets. Still, the probabilityof being exposed to their harmful radiation is unabated which demands an immediate intervention to shield humankind from beingaffected by using such devices. In our current investigation, we aimed to check the role of a high-casein diet as a protective measureagainst the biological effects of electromagnetic radiation (EMR) emerging from mobile phones on hepatic and pancreatic systemsMethods: Swiss albino mice (n=24) were fed on a standard laboratory diet (ND; n=12) and an isocaloric high-casein diet (HCD; n=12).Six mice from each dietary group were exposed to mobile phone radiation for 3 hours/day within a 3 months span. Histopathologicalalterations were studied in hepatic and pancreatic tissues by using Periodic acid-Schiff (PAS)-hematoxylin and routine H&E stainingmethods. Biochemical evaluation of total serum protein, lipid profile and glucose, total glutathione, oxidized glutathione, and antioxidantenzymatic activities of hepatic tissues were performed. Results: Hyperglycemia was noticeable along with a reduced number and areaof islets of Langerhans in radiation-exposed mice when compared to other groups. This was supported by the observation of depletedglycogen reserves in their liver. Additionally, distorted hepatic morphology with nuclear degeneration was suggestive of apoptoticprogression. The total glutathione pool was reduced on radiation exposure, hint at redox imbalance. HCD was competent in preservingthe normal pancreas and liver functioning in radiation-exposed mice.

Influence of ursodeoxycholic acid on blood glucose, insulin and GLP-1 in rats with liver fibrosis induced by bile duct ligation

BackgroundThe prevalence of impaired glucose tolerance and diabetes is much higher in people with cirrhosis than that in the general population. However, there are inadequate concrete guidelines for the management of diabetes in these patients, particularly in the early stage. Bile aids (BAs) have been found to exert hormone-like functions in the control of lipid and glucose metabolism. We studied the effect of ursodeoxycholic acid (UDCA) on glucose levels in rats with cirrhosis induced by bile duct ligation (BDL).MethodsSD rats were divided into three groups: sham operation (Group A); BDL (Group B), and UDCA plus BDL (Group C). After 4 weeks, oral glucose tolerance tests were performed. Serum biochemical parameters and the levels of glucose, insulin, and glucagon-like peptide 1 (GLP-1) were measured. Histopathology of the liver and islet was observed. The gene expression of cholesterol 7α-hydroylase (CYP7A1), microsomal oxysterol 7a-hydroxylase (CYP7B1) in the liver, and Takeda G-protein-coupled receptor-5 (TGR5) in the intestine was determined by real-time PCR.ResultsCompared with Group A, fasting glucose and 1-h and 2-h postprandial glucose levels increased slightly (all P > 0.05), 2-h postprandial insulin levels increased significantly (P < 0.05), 15 min postprandial GLP-1 levels decreased (P < 0.05) in Group B. Compared with Group B, fasting glucose and 1-h postprandial glucose levels decreased (all P < 0.05), 2-h postprandial insulin levels decreased (P < 0.01), and 15 min postprandial GLP-1 levels increased (P < 0.05) in Group C. After UDCA intervention, liver fibrosis induced by BDL was alleviated, and the islet areas were increased (P < 0.05). Compared with Group A, the mRNA expression of CYP7A1 and CYP7B1 in the liver increased, and the mRNA expression of TGR5 in the intestine decreased in Group B (all P < 0.05). Compared with Group B, the mRNA expression of CYP7A1 and CYP7B1 in the liver decreased, and TGR5 in the intestine increased in Group C (P < 0.05).ConclusionsAfter 4 weeks of BDL, the rats developed liver fibrosis and abnormal glucose metabolism. UDCA administration improved liver fibrosis, increased islet area, decreased glucose levels, inhibited genes in BA synthesis, enhanced TGR5 gene expression in the intestine, and further improved islet function.

N-3 PUFA Deficiency Aggravates Streptozotocin-Induced Pancreatic Injury in Mice but Dietary Supplementation with DHA/EPA Protects the Pancreas via Suppressing Inflammation, Oxidative Stress and Apoptosis.

It has been reported that dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) exert therapeutic potential for the preservation of functional β-cell mass. However, the effect of dietary n-3 PUFA deficiency on pancreatic injury and whether the supplementation of n-3 PUFA could prevent the development of pancreatic injury are still not clear. In the present study, an n-3 PUFA deficiency mouse model was established by feeding them with n-3 PUFA deficiency diets for 30 days. Results showed that n-3 PUFA deficiency aggravated streptozotocin (STZ)-induced pancreas injury by reducing the insulin level by 18.21% and the HOMA β-cell indices by 31.13% and the area of islet by 52.58% compared with the STZ group. Moreover, pre-intervention with DHA and EPA for 15 days could alleviate STZ-induced pancreas damage by increasing the insulin level by 55.26% and 44.33%, the HOMA β-cell indices by 118.81% and 157.26% and reversed the area of islet by 196.75% and 205.57% compared to the n-3 Def group, and the effects were significant compared to γ-linolenic acid (GLA) and alpha-linolenic acid (ALA) treatment. The possible underlying mechanisms indicated that EPA and DHA significantly reduced the ration of n-6 PUFA to n-3 PUFA and then inhibited oxidative stress, inflammation and islet β-cell apoptosis levels in pancreas tissue. The results might provide insights into the prevention and alleviation of pancreas injury by dietary intervention with PUFAs and provide a theoretical basis for their application in functional foods.

Clinacanthus nutans L Extracts Reduce the Serum Tumor Necrosis Factor-α, Malondialdehyde, and Interleukin-6 Levels and Improve the Langerhans Islet Area in Diabetic Rat Models.

Diabetes mellitus-induced hyperglycemia increases oxidative stress and inflammatory cytokine production, which play a significant role in the damage and apoptosis of pancreatic β cells. Therefore, the administration of medications that can reduce oxidative stress and inflammation plays an important role in diabetes treatment. To probe the Clinacanthus nutans leaf extract effect on oxidative stress and inflammatory markers and the Langerhans islet area in diabetic rat models. An experimental laboratory in the animal model. Twenty-five diabetic rat models were randomly assigned into 5 clusters. Clusters 1, 2, and 3 were administered with C. nutans leaf extract in aqueous suspension with vehicle 1% Na-CMC at 75 mg/kg body weight (BW), 150 mg/kg BW, and 300 mg/kg BW, respectively. Cluster 4 was diabetic control rats administered with metformin at a 21 mg/rat dose. Cluster 5 was a control diabetic rat only administered with 1% Na-CMC suspension. Treatment was administered orally for 14 days. On the 15th day, the rats were sacrificed to obtain blood samples and pancreatic tissues. Serum interleukin (IL)-6, malondialdehyde (MDA), and tumor necrosis factor (TNF-α) were measured using the enzyme-linked immunosorbent assay (ELISA) method. Histopathological examination was performed by counting the Langerhans islet areas. The average IL-6, MDA, and TNF-α levels declined in the cluster receiving C. nutans extract and were significantly different from the untreated cluster (P < .05). Histopathological examination revealed a significant upsurge in the Langerhans islets area in diabetic rats receiving C. nutans extract at doses of 75 and 150 mg/kg (P < .05). C. nutans leaf extract reduced the serum MDA, TNF-α, and IL-6 levels, and increased the Langerhans islets area in a diabetic rat model.

Antidiabetic actions of GPR55 agonist Abn-CBD and sitagliptin in obese-diabetic high fat fed mice

GPR55 has been recognized as a novel anti-diabetic target exerting positive effects on beta cell function and mass. This study evaluated the metabolic actions and therapeutic efficacy of GPR55 agonist abnormal cannabidiol (Abn-CBD) administered alone and in combination with sitagliptin in diet-induced obese-diabetic mice.Chronic effects of 21-day oral administration of Abn-CBD (0.1 µmol/kg BW) monotherapy and in combination with sitagliptin (50 mg/kg BW) were assessed in obese-diabetic HFF mice (n = 8). Assessments of plasma glucose, circulating insulin, DPP-IV activity, CRP, amylase, lipids, body weight and food intake were undertaken. Glucose tolerance, insulin sensitivity, DEXA scanning and islet morphology analysis were performed at 21-days.Sitagliptin, Abn-CBD alone and in combination with sitagliptin attenuated plasma glucose by 37–53 % (p < 0.01 – p < 0.001) and enhanced circulating insulin concentrations by 23–31 % (p < 0.001). Abn-CBD alone and with sitagliptin reduced bodyweight by 9–10 % (p < 0.05). After 21-days, Abn-CBD in combination with sitagliptin (44 %; p < 0.01) improved glucose tolerance, whilst enhancing insulin sensitivity by 79 % (p < 0.01). Abn-CBD increased islet area (86 %; p < 0.05), beta cell mass (p < 0.05) and beta cell proliferation (164 %; p < 0.001), whilst in combination with sitagliptin islet area was decreased (50 %; p < 0.01). Abn-CBD alone, in combination with sitagliptin or sitagliptin alone decreased triglycerides by 34–65 % (p < 0.001) and total cholesterol concentrations by 15–25 % (p < 0.001). In addition, Abn-CBD in combination with sitagliptin reduced fat mass by 19 % (p < 0.05) and reduced CRP concentrations (39 %; p < 0.05).These findings advocate Abn-CBD monotherapy and in combination with sitagliptin as a novel and effective approach for bodyweight control and the treatment of glucose intolerance and dyslipidaemia in type-2-diabetes.

Causes of Changing Woodland Landscape Patterns in Southern China

Forests are composed of landscape spatial units (patches) of different sizes, shapes, and characteristics. The forest landscape pattern and its trends are closely related to resistance to disturbance, restoration, stability, and the biodiversity of the forest landscape and directly influence the benefits and sustainable exploitation of forest landscape resources. Therefore, forest landscape patterns and the driving forces have increasingly attracted the attention of researchers. The present study analyzed the spatial and temporal dynamics of woodland landscape patterns in typical hilly mountainous areas in southern China using ArcGIS, landscape pattern index, and morphological spatial pattern analysis. Meanwhile, a logistic regression model was used to analyze the drivers of woodland change in Anyuan County from three aspects: natural, geographic location, and socio-economic conditions. The total area of woodland decreased during the 10-year study period, with a net decrease of 4959.27 ha, mainly due to conversion into cultivated land, garden land, and construction land. Patch density, edge density, and aggregation index of woodlands increased over time, indicating enhanced fragmentation, stable and complex patch edges, and increased patch connectivity. Conversely, the highest patch index values exhibited decreasing trends, indicating decreases in the dominant patch type. Morphological spatial pattern analysis results showed that the core area was dominant and the islet area increased over time, which also indicates enhanced fragmentation. Forest landscape change is the result of environmental change, ecological processes, and human disturbance, with geographical location and social economy having greater influences on forest landscape change. Human activities such as navel orange cultivation, returning cultivated land to forest, and land occupation for construction were the major factors driving woodland change. The results provide reference that could facilitate forest management and sustainable forest resource utilization.

Tris(4-chlorophenyl)methane and tris(4-chlorophenyl)methanol disrupt pancreatic organogenesis and gene expression in zebrafish embryos.

Tris(4-chlorophenyl) methane (TCPM) and tris(4-chlorophenyl)methanol (TCPMOH) are anthropogenic environmental contaminants believed to be manufacturing byproducts of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) due to environmental co-occurrence. TCPM and TCPMOH are persistent, bioaccumulate in the environment, and are detected in human breast milk and adipose tissues. DDT exposures have been previously shown to disrupt insulin signaling and glucoregulation, increasing risk for diabetes. We have previously shown that embryonic exposures organochlorines such as polychlorinated biphenyls disrupted pancreatic development and early embryonic glucoregulatory networks. Here, we determined the impacts of the similar compounds TCPM and TCPMOH on zebrafish pancreatic growth and gene expression following developmental exposures. Zebrafish embryos were exposed to 50 nM TCPM or TCPMOH beginning at 24 hr postfertilization (hpf) and exposures were refreshed daily. At 96 hpf, pancreatic growth and islet area were directly visualized in Tg(ptf1a::GFP) and Tg(insulin::GFP) embryos, respectively, using microscopy. Gene expression was assessed at 100 hpf with RNA sequencing. Islet and total pancreas area were reduced by 20.8% and 13% in embryos exposed to 50 nM TCPMOH compared to controls. TCPM did not induce significant morphological changes to the developing pancreas, indicating TCPMOH, but not TCPM, impairs pancreatic development despite similarity in molecular responses. Transcriptomic responses to TCPM and TCPMOH were correlated (R2 =.903), and pathway analysis found downregulation of processes including retinol metabolism, circadian rhythm, and steroid biosynthesis. Overall, our data suggest that TCPM and TCPMOH may be hazardous to embryonic growth and development.

Pancreatic alpha cell glucagon–liver FGF21 axis regulates beta cell regeneration in a mouse model of type 2 diabetes

Aims/hypothesisGlucagon receptor (GCGR) antagonism ameliorates hyperglycaemia and promotes beta cell regeneration in mouse models of type 2 diabetes. However, the underlying mechanisms remain unclear. The present study aimed to investigate the mechanism of beta cell regeneration induced by GCGR antagonism in mice.MethodsThe db/db mice and high-fat diet (HFD)+streptozotocin (STZ)-induced mice with type 2 diabetes were treated with antagonistic GCGR monoclonal antibody (mAb), and the metabolic variables and islet cell quantification were evaluated. Plasma cytokine array and liver RNA sequencing data were used to screen possible mediators, including fibroblast growth factor 21 (FGF21). ELISA, quantitative RT-PCR and western blot were applied to verify FGF21 change. Blockage of FGF21 signalling by FGF21-neutralising antibody (nAb) was used to clarify whether FGF21 was involved in the effects of GCGR mAb on the expression of beta cell identity-related genes under plasma-conditional culture and hepatocyte co-culture conditions. FGF21 nAb-treated db/db mice, systemic Fgf21-knockout (Fgf21−/−) diabetic mice and hepatocyte-specific Fgf21-knockout (Fgf21Hep−/−) diabetic mice were used to reveal the involvement of FGF21 in beta cell regeneration. A BrdU tracing study was used to analyse beta cell proliferation in diabetic mice treated with GCGR mAb.ResultsGCGR mAb treatment improved blood glucose control, and increased islet number (db/db 1.6±0.1 vs 0.8±0.1 per mm2, p<0.001; HFD+STZ 1.2±0.1 vs 0.5±0.1 per mm2, p<0.01) and area (db/db 2.5±0.2 vs 1.2±0.2%, p<0.001; HFD+STZ 1.0±0.1 vs 0.3±0.1%, p<0.01) in diabetic mice. The plasma cytokine array and liver RNA sequencing data showed that FGF21 levels in plasma and liver were upregulated by GCGR antagonism. The GCGR mAb induced upregulation of plasma FGF21 levels (db/db 661.5±40.0 vs 466.2±55.7 pg/ml, p<0.05; HFD+STZ 877.0±106.8 vs 445.5±54.0 pg/ml, p<0.05) and the liver levels of Fgf21 mRNA (db/db 3.2±0.5 vs 1.8±0.1, p<0.05; HFD+STZ 2.0±0.3 vs 1.0±0.2, p<0.05) and protein (db/db 2.0±0.2 vs 1.4±0.1, p<0.05; HFD+STZ 1.6±0.1 vs 1.0±0.1, p<0.01). Exposure to plasma or hepatocytes from the GCGR mAb-treated mice upregulated the mRNA levels of characteristic genes associated with beta cell identity in cultured mouse islets and a beta cell line, and blockage of FGF21 activity by an FGF21 nAb diminished this upregulation. Notably, the effects of increased beta cell number induced by GCGR mAb were attenuated in FGF21 nAb-treated db/db mice, Fgf21−/− diabetic mice and Fgf21Hep−/− diabetic mice. Moreover, GCGR mAb treatment enhanced beta cell proliferation in the two groups of diabetic mice, and this effect was weakened in Fgf21−/− and Fgf21Hep−/− mice.Conclusions/interpretationOur findings demonstrate that liver-derived FGF21 is involved in the GCGR antagonism-induced beta cell regeneration in a mouse model of type 2 diabetes.Graphical abstract

Black phosphorus quantum dots cause glucose metabolism disorder and insulin resistance in mice

Black phosphorus quantum dots (BPQDs) are considered to have wide application prospects due to their excellent properties. However, there is no study on the effect of BPQDs on glucose metabolism. In this study, blood glucose was significantly increased when mice were continuously intragastrically administered 0.1 and 1 mg/kg bw BPQDs. The blood glucose level of the mice was elevated from Day 7 to Day 28. BPQD exposure also decreased the area under the curve (AUC) of the oral glucose tolerance test (OGTT). After exposure, the pancreas somatic index was increased. Moreover, the serum insulin and glucagon levels were elevated and the relative area of islet β cells was increased in BPQD-exposed mice, while insulin signaling cascades were reduced in muscle tissues. In summary, our study demonstrated for the first time that BPQD exposure induces glucose disorder and insulin resistance in muscle, which is helpful to understand the biosafety of black phosphorus nanomaterials and promote the sustainable development of nanotechnology.

Differential effects of RYGB surgery and best medical treatment for obesity-diabetes on intestinal and islet adaptations in obese-diabetic ZDSD rats.

Modification of gut-islet secretions after Roux-En-Y gastric bypass (RYBG) surgery contributes to its metabolic and anti-diabetic benefits. However, there is limited knowledge on tissue-specific hormone distribution post-RYGB surgery and how this compares with best medical treatment (BMT). In the present study, pancreatic and ileal tissues were excised from male Zucker-Diabetic Sprague Dawley (ZDSD) rats 8-weeks after RYGB, BMT (daily oral dosing with metformin 300mg/kg, fenofibrate 100mg/kg, ramipril 1mg/kg, rosuvastatin 10mg/kg and subcutaneous liraglutide 0.2mg/kg) or sham operation (laparotomy). Insulin, glucagon, somatostatin, PYY, GLP-1 and GIP expression patterns were assessed using immunocytochemistry and analyzed using ImageJ. After RYGB and BMT, body weight and plasma glucose were decreased. Intestinal morphometry was unaltered by RYGB, but crypt depth was decreased by BMT. Intestinal PYY cells were increased by both interventions. GLP-1- and GIP-cell counts were unchanged by RYGB but BMT increased ileal GLP-1-cells and decreased those expressing GIP. The intestinal contents of PYY and GLP-1 were significantly enhanced by RYGB, whereas BMT decreased ileal GLP-1. No changes of islet and beta-cell area or proliferation were observed, but the extent of beta-cell apoptosis and islet integrity calculated using circularity index were improved by both treatments. Significantly decreased islet alpha-cell areas were observed in both groups, while beta- and PYY-cell areas were unchanged. RYGB also induced a decrease in islet delta-cell area. PYY and GLP-1 colocalization with glucagon in islets was significantly decreased in both groups, while co-staining of PYY with glucagon was decreased and that with somatostatin increased. These data characterize significant cellular islet and intestinal adaptations following RYGB and BMT associated with amelioration of obesity-diabetes in ZDSD rats. The differential responses observed and particularly those within islets, may provide important clues to the unique ability of RYGB to cause diabetes remission.

Effect of electroacupuncture on protein expressions of SOCS3 and IRS-1 in hypothalamus and pancreas islet morphology in diabetic fatty rats

To observe the effect of electroacupuncture (EA) on protein expressions of suppressor of cytokine signaling 3 (SOCS3) and insulin receptor substrate-1 (IRS-1) in hypothalamus and morphology of pancreas islet in Zucker diabetic fatty (ZDF) rats, and to explore its possible mechanism on improving plasma glucose and insulin resistance of type 2 diabetes mellitus (T2DM). Twelve SPF male ZDF rats were selected and fed with high-fat diet for 4 weeks to establish the T2DM model, after modeling, the rats were randomly divided into a model group and an EA group, 6 rats in each one. Besides, 6 SPF male Zucker lean rats were selected as a blank group. In the EA group, EA was applied at "Pishu" (BL 20), "Weiwanxiashu" (EX-B 3), "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), with continuous wave, 15 Hz in frequency, 2 mA in intensity, once a day, 20 min each time, 6 times a week for 4 weeks. The fasting plasma glucose (FPG) was measured before and after intervention. The serum level of fasting insulin (FINS) was measured by radioimmunoassay, and the homeostasis model assessment of insulin resistance index (HOMA-IR) was calculated; the morphological change of pancreas islets was observed by HE staining; the protein expressions of SOCS3 and IRS-1 in hypothalamus were detected by Western blot. Before intervention, compared with the blank group, FPG in the model group and the EA group was increased (P<0.01). After intervention, compared with the blank group, FPG, serum level of FINS and HOMA-IR were increased (P<0.01), the protein expression of SOCS3 was increased while IRS-1 was decreased in the hypothalamus in the model group (P<0.01). Compared with the model group, FPG, serum level of FINS and HOMA-IR were decreased (P<0.01), the protein expression of SOCS3 was decreased while IRS-1 was increased in the hypothalamus in the EA group (P<0.01). In the model group, the shape of pancreas islets was irregular, the area of pancreas islets and the number of islet β cell nuclei were decreased, the nuclei of islet β cell was compensatory enlargement. In the EA group, the shape and the area of pancreas islets and the number of islet β cell nuclei were improved, the compensatory increase of islet β cell nuclei was alleviated compared with the model group. Electroacupuncture can reduce the fasting plasma glucose, improve the morphology of pancreas islets, and alleviate the insulin resistance in ZDF rats. The mechanism may relate to the down-regulation of SOCS3 and up-regulation of IRS-1 in the hypothalamus, and improving the function of hypothalamus in regulating peripheral glucose metabolism.

Bisfenol F’nin Sıçan Pankreası Üzerindeki Toksik Etkileri

Bu çalışmada, bisfenol F (BPF)’nin sıçan pankreası üzerindeki toksik etkilerinin belirlenmesi amaçlandı. Bu amaç doğrultusunda yirmi sekiz adet Wistar albino erkek sıçan, BPF’ye 0, 20, 100 ve 500 mg/kg vücut ağırlığı (v.a.) konsantrasyonlarda, 28 gün boyunca oral gavaj ile maruz bırakıldı. Histolojik incelemelere göre BPF maruziyeti sonrasında, pankreatik Langerhans adacıklarında vakuolar dejenerasyon gösteren hücrelerin varlığı tespit edildi. Histomorfolojik ölçümler, BPF’nin 100 ve 500 mg/kg v.a. konsantrasyonlarına maruz bırakılan gruplarda, adacık çap ve alan ortalamalarının düştüğünü gösterdi. Ek olarak, adacıklarda immunohistokimyasal olarak boyayan insülin pozitif  hücre yüzdesinin, BPF uygulanan bütün gruplarda, anlamlı bir şekilde azaldığı tespit edildi. Serum açlık glukoz, total kan HbA1c ve serum C-peptid ile insülin seviyelerinin, BPF maruziyeti sonrasında anlamlı değişimler göstermedikleri gözlendi. BPF’nin malondialdehit düzeyi dışında, pankreas antioksidan savunma sistemi belirteçlerinde anlamlı değişimlere yol açtığı belirlendi. Elde edilen sonuçlar BPF’nin endüstriyel alanlarda, bisfenol A yerine güvenilir bir alternatif olarak, kullanımına daha fazla dikkat edilmesi gerektiğini göstermektedir.

Insulin expression in β cells is reduced within islets before islet loss in diabetic cats.

Diabetes mellitus is a common condition that requires intensive treatment and markedly impacts the welfare of affected cats. The aim of this study was to identify diabetes mellitus-associated perturbations in the feline pancreatic islet microenvironment. The utility of "clear, unobstructed brain/body imaging cocktails and computational analysis" (CUBIC) for three-dimensional pancreatic analysis was investigated. Formalin-fixed paraffin-embedded tissues from cats with diabetes mellitus, or control cats without pancreatic pathology, were retrospectively identified. Immunohistochemistry for synaptophysin and ionised calcium binding adaptor molecule 1, and immunofluorescence for insulin and synaptophysin, were used to assess changes in islets. An image analysis pipeline was developed to analyse images acquired from two-dimensional immunofluorescence. CUBIC was used to optically clear selected pancreas samples before immunofluorescence and deep three-dimensional confocal microscopy. Diabetic cats have a significant reduction in synaptophysin-positive islet area. Whilst islets from diabetic patients have similar numbers of β cells to islets from control cats, significantly lower intensity of insulin expression can be observed in the former. CUBIC facilitates clear visualisation of pancreatic islets in three dimensions. The data presented support the theory that there is a decrease in function of β cells before their destruction, suggesting a potentially significant step in the pathogenesis of feline diabetes mellitus. In parallel, we demonstrate CUBIC as a valuable new tool to visualise the shape of feline pancreatic islets and to interrogate pathology occurring in the islets of diabetic pets.

Nrf2a dependent and independent effects of early life exposure to 3,3'-dichlorobiphenyl (PCB-11) in zebrafish (Danio rerio).

The environmental pollutant 3,3'-dichlorobiphenyl (PCB-11) is a lower-chlorinated polychlorinated biphenyl (PCB) congener present in air and water samples. Both PCB-11 and its metabolite, 4-PCB-11-Sulfate, are detected in humans, including in pregnant women. Previous research in zebrafish (Danio rerio) has shown that 0.2μM exposures to 4-PCB-11-Sulfate starting at 1 day post fertilization (dpf) increase hepatic neutral lipid accumulation in larvae at 15 dpf. Here, we explored whether nuclear factor erythroid 2-related factor 2 (Nrf2), known as the master-regulator of the adaptive response to oxidative stress, contributes to metabolic impacts of 4-PCB-11-Sulfate. For this work, embryos were collected from homozygous wildtype or Nrf2a mutant adult zebrafish that also express GFP in pancreatic β-cells, rendering Tg(ins:GFP;nrf2afh318+/+) and Tg(ins:GFP;nrf2afh318-/-) lines. Exposures were conducted from 1-15 dpf to either 0.05% DMSO or DMSO-matched 0.2µM 4-PCB-11-Sulfate, and at 15 dpf subsets of larvae were imaged for overall morphology, primary pancreatic islet area, and collected for fatty acid profiling and RNAseq. At 15 dpf, independent of genotype, fish exposed to 4-PCB-11-Sulfate survived significantly more at 80-85% compared to 65-73% survival for unexposed fish, and had primary pancreatic islets 8% larger compared to unexposed fish. Fish growth at 15 dpf was dependent on genotype, with Nrf2a mutant fish a significant 3-5% shorter than wildtype fish, and an interaction effect was observed where Nrf2a mutant fish exposed to 4-PCB-11-Sulfate experienced a significant 29% decrease in the omega-3 fatty acid DHA compared to unexposed mutant fish. RNAseq revealed 308 differentially expressed genes, most of which were dependent on genotype. These findings suggest that Nrf2a plays an important role in growth as well as for DHA production in the presence of 4-PCB-11-Sulfate. Further research would be beneficial to understand the importance of Nrf2a throughout the lifecourse, especially in the context of toxicant exposures.

Ameliorative role of Cyanus depressus (M.Bieb.) Soják plant extract against diabetes-associated oxidative-stress-induced liver, kidney, and pancreas damage in rats.

In this original article, we aimed to assess the ameliorative role of Cyanus depressus (CD) plant ethanolic extract treatment of streptozotocin (STZ)-induced liver, kidney, and pancreas damage in rats. The rats were divided into five groups (n=7): control, CD, Diabetes mellitus (DM), DM + CD, and DM + glibenclamide (Gly). The DM groups were injected with a single dose of 50 mg/kg STZ intraperitoneally (i.p.). While the CD and DM + CD groups received 400 mg/kg/day intragastrically for 21 days, the DM + Gly group received 3mg/kg/day of Gly intragastrically throughout the experiment. Statistically significance was accepted as p < .05. According to our liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) data, quinic acid, cosmosiin, nicotiflorin, apigenin, and protocatechuic acid were the major compounds, in descending order. Weekly blood glucose, serum glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and urea, malondialdehyde (MDA) (liver and pancreas), and blood glycosylated hemoglobin % (HbA1c %) were significantly decreased, whereas finally live body weights (LBWs), reduced glutathione (GSH), glutathione S-transferase (GST) and catalase (CAT) (pancreas), and pancreatic islet diameter and area were increased significantly in the CD-treated diabetic group. Moreover, CD administration was found to be effective in the protection of the histology of the liver, kidneys, and pancreatic islets in the STZ-induced rats. Consequently, we concluded that CD administration reduces hyperglycemia, oxidative stress, and histopathology in STZ-induced experimental rats by improving antioxidant defenses. PRACTICAL APPLICATIONS: Today, the prevalence of diabetes is increasing rapidly throughout the world and it causes complications such as kidney damage, blindness, amputations, and cardiovascular diseases. Despite medical technological advances, people's interest in medicinal herbal products is gradually increasing. Biochemical and histopathological findings showed that the use of the plant CD at the determined dose (400 mg/kg/day) in rats with DM by STZ had strong antioxidant and antidiabetic effects. CD may have a drug potential in preventing DM and its complications because of its phytochemical content including some phenolic acids such as quinic acid, cosmosiin, nicotiflorin, apigenin, and protocatechuic acid. Isolation of bioactive compounds from CD and investigation of their therapeutic effects could be planned as further studies.

Neuroprotective Substances: Are they Able to Protect the Pancreatic Beta- Cells Too?

Growing pieces of evidence demonstrate a close relationship between type 2 diabetes (T2D) and neurodegenerative disorders such as Alzheimer's disease. The similarity of physiological and pathological processes occurring in pancreatic β-cells and neurons over the course of these pathologies allows raising the question of the practicability of studying neuroprotective substances for their potential antidiabetic activity. This review analyzes studies of antidiabetic and cytoprotective action on pancreatic β- cells of the neuroprotective compounds that can attenuate the oxidative stress and enhance the expression of neurotrophins: low-molecular-weight NGF mimetic compound GK-2, selective anxiolytic afobazole, antidepressants lithium chloride, and lithium carbonate on the rat streptozotocin model of T2D. It was found that all the above-listed neuroprotective substances have a pronounced antidiabetic activity. The decrease in the β-cells number, the average area of the pancreatic islets, as well as the violation of their morphological structure caused by the streptozotocin was significantly weakened by the therapy with the investigated neuroprotective substances. The extent of these morphological changes clearly correlates with the antihyperglycemic effect of these compounds. The presented data indicate that the neuroprotective substances attenuating the damaging effect of oxidative stress and neurotrophins deficit cannot only protect neurons but also exert their cytoprotective effect towards pancreatic β-cells. These data may provide a theoretical basis for the further study of neuroprotective drugs as potential therapeutic options for T2D prevention and treatment.

Impact of biotin supplemented diet on mouse pancreatic islet β-cell mass expansion and glucose induced electrical activity

ABSTRACT Biotin supplemented diet (BSD) is known to enhance β-cell replication and insulin secretion in mice. Here, we first describe BSD impact on the islet β-cell membrane potential (Vm) and glucose-induced electrical activity. BALB/c female mice (n ≥ 20) were fed for nine weeks after weaning with a control diet (CD) or a BSD (100X). In both groups, islet area was compared in pancreatic sections incubated with anti-insulin and anti-glucagon antibodies; Vm was recorded in micro dissected islet β-cells during perfusion with saline solutions containing 2.8, 5.0, 7.5-, or 11.0 mM glucose. BSD increased the islet and β-cell area compared with CD. In islet β-cells of the BSD group, a larger ΔVm/Δ[glucose] was found at sub-stimulatory glucose concentrations and the threshold glucose concentration for generation of action potentials (APs) was increased by 1.23 mM. Moreover, at 11.0 mM glucose, a significant decrease was found in AP amplitude, frequency, ascending and descending slopes as well as in the calculated net charge influx and efflux of islet β-cells from BSD compared to the CD group, without changes in slow Vm oscillation parameters. A pharmacological dose of biotin in mice increases islet insulin cell mass, shifts islet β-cell intracellular electrical activity dose response curve toward higher glucose concentrations, very likely by increasing KATP conductance, and decreases voltage gated Ca2+ and K+ conductance at stimulatory glucose concentrations.

13-OR: Cystic Fibrosis Donors Exhibit Striking Decrease in Pancreatic Islet and Exocrine Capillaries

Glucose intolerance and insulin deficiency are common features of cystic fibrosis (CF) , with nearly half of adult CF patients developing CF-related diabetes (CFRD) , but the underlying pathophysiology remains poorly understood. Extensive destruction of the exocrine pancreas occurs in most CF patients. However, islets are still readily detectable, suggesting β cell loss is not the major driver of impaired insulin release. Islets are normally highly vascularized, and islet capillaries are the source of key growth factors that maintain β cell health and function. Islet capillary morphology is altered in type 1 and type 2 diabetes, with increased capillary density and/or vessel thickening being observed. In the present study we aimed to determine whether islet capillaries are also disrupted in CF/CFRD. Pancreas sections (8 control and 8 CF/CFRD, age-matched) were stained for CD31, a marker of vascular endothelial cells. Islets in microscopy images were manually identified (17.8±2.8[SEM] per sample) and CD31-positive area within islet and exocrine was quantified. Mean islet cross-sectional area did not significantly differ between CF and non-CF pancreas specimens. CD31 positive area, expressed as a fraction of islet area, was significantly decreased in CF pancreas specimens (2.8±0.9% vs. 6.1±1.2%; p=0.05) . Islet capillary density (the number of CD31+ objects normalized to islet area) was also decreased (0.88±0.17x103/μm2 vs. 3.8±0.57x103/μm2; p=0.0004) , as was exocrine tissue CD31 positive area (0.17±0.03% vs. 1.5±0.23%; p&amp;lt;0.0001) . Our data demonstrate a significant deficit in islet and pancreatic vascularity in CF/CFRD. This contrasts markedly with the increase in islet capillary density seen in both T1D and T2D and underscores the presence of distinct features of islet morphology that characterize CF. Given that islet capillaries support β-cell function and survival, their loss likely contributes to impaired β-cell function. Disclosure J.J.Castillo: None. A.Aplin: None. R.Akter: None. R.L.Hull-meichle: Research Support; Casma Therapeutics. Funding Cystic Fibrosis Foundation Fellowship (CASTIL20F0)

1394-P: Peri-Islet Glial-Cell Expansion Occurs in Response to High-Fat Diet-Induced Obesity and Hyperglycemia

Peri-islet glial cells (PIGCs) are positioned to control neuronal-endocrine-vascular cell communication within the islet, but their role in islet cell function is not known. Hypothalamic glial cells become reactive in response to high fat diet (HFD) feeding and are implicated in the pathogenesis of obesity and type 2 diabetes. We hypothesize that metabolic stress such as diet-induced obesity and hyperglycemia promote the expansion of PIGCs, similar to what has been observed in the central nervous system. To test this hypothesis, we used the glial cell marker, glial fibrillary acidic protein (GFAP) , to identify PIGCs and compared GFAP immunoreactivity in pancreas from the following groups. First, pancreas was harvested from HFD- or chow fed control C57BL/6J male mice after 2 days, 2 weeks or 8 weeks on diet (n=6-8/group) . Second, pancreas was taken from 12-wk old db/db male mice and their control littermates with or without empagliflozin (EMPA) treatment (20mg/kg/d for 6 weeks; n=4-7/group) . Islet PIGC area was quantified as GFAP-positive area/total islet area x100%. Mann-Whitney test and one-way ANOVA were used for data analysis. We found that HFD feeding increased mouse pancreatic peri-islet GFAP expression relative to chow controls at 2 days (HFD 1.4±0.2%, chow 0.8±0.1%; p=0.02) , 2 weeks (HFD 3.5±0.4%, chow 1.2±0.1%; p&amp;lt;0.001) and 8 weeks (HFD 5.4±0.3%, chow 1.8±0.2%; p=0.002) in association with body weight gain and impaired glucose tolerance. Similar results were observed in obese and hyperglycemic db/db mouse vs. control littermates (db/db 5.0±1.4%, control 1.2±0.4%; p=0.004) . There was a trend for EMPA treatment to reduce islet PIGC area in the db/db mice (EMPA 2.0±0.5, VEH 5.0±1.4%, p=0.08) . In conclusion, these findings indicate that islet gliosis is observed in two obese and hyperglycemic mouse models and raise the possibility that pancreatic ‘gliosis’ may have a relevant role in islet-cell function regulation under metabolic challenge. Disclosure J.Niu: None. J.B.Moss: None. W.Rosario: Employee; Merck &amp; Co., Inc. R.Arumugam: None. D.J.Hackney: None. R.L.Hull-meichle: Research Support; Casma Therapeutics. J.Tong: None. Funding National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases (R01DK097550) ;Department of Veterans Affairs (IBX004063)

1449-P: Reducing Ghrelin Levels as a Novel Method to Increase Pancreatic Beta-Cell Mass

Objective: Exogenous insulin remains the leading therapy for type 1 diabetes mellitus, T1D. However, current insulin formulations and delivery methods do not match the precision of functioning beta-cells, and even intensive monitoring of blood glucose and use of insulin pumps are not enough to halt frequent hypoglycemia, hyperglycemia and morbidity. Thus, regenerating beta-cells has become a major target of diabetes research to treat T1D. While the hormone ghrelin is well known to increase blood glucose, at least in part by inhibiting insulin secretion, ghrelin’s action on beta-cell mass and proliferation has heretofore not been explored in detail. Here, we sought to test the hypothesis that reducing ghrelin levels increases beta-cell mass. Methods: Using histologic methods, we compared islet anatomy in ghrelin-knockout (ghrelin-KO) mice vs. wildtype littermates at three different ages: newborns (P0-P2) , juveniles (4-week-old) , and adults (10-12-week-old) . We also compared islet anatomy in adult wildtype mice, 4 weeks following conditional ghrelin-cell ablation vs. wildtype mice with intact ghrelin-cells. n= 4-8 mice per group and 33-433 islets per mouse. Results: Ghrelin gene deletion or ghrelin-cell ablation increased mean islet area and mean islet insulin-immunoreactive (insulin-IR) area by 52-82 % and by 45-51 %, respectively, in juveniles and adults. Increased islet size was driven by an increased % of large islets. Increased insulin-IR area was associated with increased beta-cell number per islet. An increased % of large islets was also observed in newborn ghrelin-KO mice. Conclusions: In mice, ghrelin plays an important role in controlling beta-cell mass. Reducing ghrelin levels for even short periods can increase islet size by increasing beta-cell numbers. Disclosure D.Gupta: None. C.P.Richard: None. J.M.Zigman: Research Support; Novo Nordisk Research Center Indianapolis, Novo Nordisk Research Center Indianapolis, Stock/Shareholder; Medtronic, Medtronic. A.W.Burstein: None. K.Shankar: None. S.Varshney: None. O.Singh: None. S.Paul: None. S.B.Ogden: None. S.Osborne-lawrence: None. N.Metzger: None.