Increase In Insulin Concentration Research Articles

Placental small extracellular vesicles from normal pregnancy and gestational diabetes increase insulin gene transcription and content in β cells.

Insulin secretion increases progressively during pregnancy to maintain normal maternal blood glucose levels. The placenta plays a crucial role in this process by releasing hormones and extracellular vesicles into the maternal circulation, which drive significant changes in pregnancy physiology. Placental extracellular vesicles, which are detectable in the plasma of pregnant women, have been shown to signal peripheral tissues and contribute to pregnancy-related conditions. While studies using murine models have demonstrated that extracellular vesicles can modulate insulin secretion in pancreatic islets, it remains unclear whether these effects translate to human biology. Understanding how placental signals enhance insulin synthesis and secretion from β cells could be pivotal in developing new therapies for diabetes. In our study, we isolated placental small extracellular vesicles from human placentae and utilised the human β cell line, EndoC-βH3, to investigate their effects on β-cell function in vitro. Our results indicate that human β cells internalise placental small extracellular vesicles, leading to enhanced insulin gene expression and increased insulin content within the β cells. Moreover, these vesicles up-regulated the expression of Annexin A1, a protein known to increase insulin content. This up-regulation of Annexin A1 holds promise as a potential mechanism by which placental small extracellular vesicles enhance insulin biosynthesis.

Beta cell-specific PAK1 enrichment ameliorates diet-induced glucose intolerance in mice by promoting insulin biogenesis and minimising beta cell apoptosis.

p21 (CDC42/RAC1) activated kinase 1 (PAK1) is depleted in type 2 diabetic human islets compared with non-diabetic human islets, and acute PAK1 restoration in the islets can restore insulin secretory function ex vivo. We hypothesised that beta cell-specific PAK1 enrichment in vivo can mitigate high-fat-diet (HFD)-induced glucose intolerance by increasing the functional beta cell mass. Human islets expressing exogenous PAK1 specifically in beta cells were used for bulk RNA-seq. Human EndoC-βH1 cells overexpressing myc-tagged PAK1 were used for chromatin immunoprecipitation (ChIP) and ChIP-sequencing (ChIP-seq). Novel doxycycline-inducible beta cell-specific PAK1-expressing (iβPAK1-Tg) mice were fed a 45% HFD pre-induction for 3 weeks and for a further 3 weeks with or without doxycycline induction. These HFD-fed mice were evaluated for GTT, ITT, 6 h fasting plasma insulin and blood glucose, body composition, islet insulin content and apoptosis. Beta cell-specific PAK1 enrichment in type 2 diabetes human islets resulted in decreased beta cell apoptosis and increased insulin content. RNA-seq showed an upregulation of INS gene transcription by PAK1. Using clonal human beta cells, we found that PAK1 protein was localised in the cytoplasm and the nucleus. ChIP studies revealed that nuclear PAK1 enhanced pancreatic and duodenal homeobox1 (PDX1) and neuronal differentiation 1 (NEUROD1) binding to the INS promoter in a glucose-responsive manner. Importantly, the iβPAK1-Tg mice, when challenged with HFD and doxycycline induction displayed enhanced glucose tolerance, increased islet insulin content and reduced beta cell apoptosis when compared with iβPAK1-Tg mice without doxycycline induction. PAK1 plays an unforeseen and beneficial role in beta cells by promoting insulin biogenesis via enhancing the expression of PDX1, NEUROD1 and INS, along with anti-apoptotic effects, that culminate in increased insulin content and beta cell mass in vivo and ameliorate diet-induced glucose intolerance. The raw and processed RNA-seq data and ChIP-seq data, which has been made publicly available at Gene Expression Omnibus (GEO) at https://www.ncbi.nlm.nih.gov/geo/ , can be accessed in GSE239382.

Chronic late gestation fetal hyperglucagonaemia results in lower insulin secretion, pancreatic mass, islet area and beta- and α-cell proliferation.

Fetal glucagon concentrations are elevated in the presence of a compromised intrauterine environment, as in cases of placental insufficiency and perinatal acidaemia. Our objective was to investigate the impact of late gestation fetal hyperglucagonaemia on in vivo insulin secretion and pancreatic islet structure. Chronically catheterized late gestation fetal sheep received an intravenous infusion of glucagon at low (5ng/kg/min; GCG-5) or high (50ng/kg/min; GCG-50) concentrations or a vehicle control (CON) for 8-10days.Glucose-stimulated fetal insulin secretion (GSIS) was measured following 3h (acute response) and 8-10days (chronic response) of experimental infusions. Insulin, glucose and amino acid concentrations were measured longitudinally. The pancreas was collected at the study end for histology and gene expression analysis. Acute exposure (3h) to GCG-50 induced a 3-fold increase in basal insulin concentrations with greater GSIS. Meanwhile, chronic exposure to both GCG-5 and GCG-50 decreased basal insulin concentrations 2-fold by day 8-10. Chronic GCG-50 also blunted GSIS at the study end. Fetal amino acid concentrations were decreased within 24h of GCG-5 and GCG-50, while there were no differences in fetal glucose. Histologically, GCG-5 and GCG-50 had lower β- and α-cell proliferation, as well as lower α-cell mass and pancreas weight, while GCG-50 had lower islet area. This study demonstrates that chronic glucagon elevation in late gestation fetuses impairs β-cell proliferation and insulin secretion, which has the potential to contribute to later-life diabetes risk. We speculate that the action of glucagon in lower circulating fetal amino acid concentrations may have a suppressive effect on insulin secretion. KEY POINTS: We have previously demonstrated in a chronically catheterized fetal sheep model that experimentally elevated glucagon in the fetus impairs placental function, reduces fetal protein accretion and lowers fetal weight. In the present study, we further characterized the effects of elevated fetal glucagon on fetal physiology with a focus on pancreatic development and β-cell function. We show that experimentally elevated fetal glucagon results in lower β- and α-cell proliferation, as well as decreased insulin secretion after 8-10days of glucagon infusion. These results have important implications for β-cell reserve and later-life predisposition to diabetes.

7799 Nesidioblastosis Concurrent with Anatomically Confirmed Metastatic Gastric Cancer

Abstract Disclosure: Y. Cho: None. K. Jo: None. J. Han: None. S. Moon: None. E. Kim: None. Background: Nesidioblastosis is a rare condition that should be considered in cases of pancreatogenic hyperinsulinemic hypoglycemia without evidence of insulinoma on imaging. We present the first case of nesidioblastosis concomitant with anatomically confirmed metastatic gastric cancer of the pancreas. Case Report A 57-year-old male presented with recurrent episodes of loss of consciousness and hypoglycemia, with a glucose level of 26 mg/dl upon arrival at the emergency room. Despite a history of advanced gastric cancer and previous chemotherapy, the patient had not been diagnosed with diabetes and was not taking medications associated with hypoglycemia. Four months prior, he underwent total gastrectomy. The fasting plasma glucose levels was 38 mg/dl, accompanied by C-peptide levels of 6.10 ng/mL, insulin levels exceeding 1000 uIU/ml, and proinsulin levels at 8.8 pmol/L. The insulin antibody level was more than 100%, and the highest cortisol level reached 15.60 ug/dL during the rapid ACTH stimulation test. The patient's postprandial 2-hour glucose level reached 233 mg/dl during the 75g glucose tolerance test. Imaging studies, including whole-body PET CT and abdominal CT, showed no evidence of suspected metastatic lesions, and the pancreas appeared normal on MRI. Endoscopic ultrasound could not be performed due to anatomical changes following the surgery. A selective arterial calcium stimulation test demonstrated a substantial over twofold increase in insulin concentrations in the gastroduodenal artery, splenic artery, and superior mesenteric artery. The patient received methylprednisolone 125 mg once daily but insulin levels remained elevated, exceeding 1000 uIU/ml, requiring continuous dextrose infusion. Octreotide therapy was initiated, resulting in an improvement in insulin levels to 589 uIU/ml, although discontinuation of dextrose fluid remained unfeasible. After consultation with the surgeon, a open subtotal pancreatectomy was performed, allowing discontinuation of dextrose on the second post-surgery day, with improved glucose and insulin levels. Histological examination showed three clusters of atypical cells with perineural infiltration. Immunostaining indicated negative synaptophysin and positive CK20, suggesting possible gastric cancer metastasis, consistent with prior gastrectomy findings. Moreover, an increased number of variable-sized Langerhans islets exhibited positive insulin and glucagon immunostaining within the islets, indicative of nesidioblastosis. Conclusion: Nesidioblastosis should be considered in cases of unexplained post-surgery hypoglycemia following metastatic gastric cancer treatment. Furthermore, given the potential link with metastatic gastric cancer, which may elude detection via imaging alone, aggressive surgical intervention should be contemplated as a nesidioblastosis treatment strategy. Presentation: 6/3/2024

The role of mu-opioid receptors in pancreatic islet α-cells.

Diabetes is a complex disease that impacts more than 500 million people across the world. Many of these individuals will develop diabetic neuropathy as a comorbidity, which is historically treated with exogenous opioids like morphine, oxycodone, or tramadol. Although these opioids are effective analgesics, growing evidence indicates that they may directly impact the endocrine pancreas function in patients. One common feature of these exogenous opioid ligands is their preference for the mu opioid receptor (MOPR), so we aimed to determine if endogenous MOPRs directly regulate pancreatic islet metabolism and hormone secretion. We show that pharmacological antagonism of MOPRs enhances glucagon secretion, but not insulin secretion, from human islets under high glucose conditions. This increased secretion is accompanied by increased cAMP signaling. mRNA expression of MOPRs is robust in non-diabetic human islets, but downregulated in islets from T2D donors, suggesting a link between metabolism and MOPR expression. Conditional genetic knockout of MOPRs in murine α-cells increases glucagon secretion under high glucose conditions without increasing glucagon content. Consistent with downregulation of MOPRs during metabolic disease, conditional MOPR knockout mice treated with a high fat diet show impaired glucose tolerance, increased glucagon secretion, increased insulin content, and increased islet size. Together, these results demonstrate a direct mechanism of action for endogenous opioid regulation of endocrine pancreas.

Fasting triglyceride concentrations are associated with markers of lipid metabolism and glucose homeostasis in healthy, non-obese dogs in lean and overweight condition.

Serum triglyceride concentrations increase in dogs with obesity, which is typically assessed by body condition score (BCS), however little is known about changes that take place in non-obese dogs in overweight condition. Further, the associations of triglyceride levels with other markers of energy homeostasis are poorly characterised in healthy animals. The present study aimed to evaluate associations between both BCS and triglyceride concentrations with other markers of lipid and glucose metabolism in healthy, non-obese dogs, as well as to assess whether these markers change significantly in non-obese dogs with overweight as compared to their lean counterparts. Serum concentrations of cholesterol, free fatty acids, triglycerides, insulin, glucose and fructosamine were measured in 532 healthy, client-owned dogs, assigned either to 'lean' (BCS: 3-5) or 'overweight' (BCS: 6-7) categories. Generalised linear mixed models were used to assess associations between BCS categories, triglyceride concentrations and other variables, correcting for the effect of breed. Compared with lean dogs, overweight dogs had a greater serum cholesterol concentration (95% CI, 5.3-6.2 mmol/L or 205-237 mg/dL versus 5.1-5.4 mmol/L or 198-210 mg/dL, p = 0.0032), insulin concentration (95% CI, 17.5-22.1 μU/ml versus 16.7-18.0 μU/ml, p = 0.0374) and were older (95% CI, 4.0-5.3 versus 3.4-3.7 years, p = 0.0005). Triglyceride concentrations were positively associated with fructosamine (r 2 = 0.31, p = 0.0012), cholesterol (r 2 = 0.25, p < 0.0001), insulin (r 2 = 0.14, p = 0.0030) and glucose (r 2 = 0.10, p = 0.0014) concentrations, and negatively associated with free fatty acid concentrations (r 2 = 0.11, p < 0.0001). However, there was no association between triglyceride concentrations and age. In conclusion, both BCS and triglyceride concentrations were associated with other markers of glucose and lipid metabolism in non-obese healthy dogs, amongst which those with overweight showed metabolic changes as compared to their lean counterparts. Triglyceride concentrations were associated with an increase in insulin and fructosamine concentrations that might reflect an early-phase impairment in glucose tolerance which, surprisingly, was concurrent with lower basal free fatty acid concentrations.

Causal associations between insulin and Lp(a) levels in Caucasian population: a Mendelian randomization study

BackgroundNumerous observational studies have demonstrated that circulating lipoprotein(a) [Lp(a)] might be inversely related to the risk of type 2 diabetes (T2D). However, recent Mendelian randomization (MR) studies do not consistently support this association. The results of in vitro research suggest that high insulin concentrations can suppress Lp(a) levels by affecting apolipoprotein(a) [apo(a)] synthesis. This study aimed to identify the relationship between genetically predicted insulin concentrations and Lp(a) levels, which may partly explain the associations between low Lp(a) levels and increased risk of T2D.MethodsIndependent genetic variants strongly associated with fasting insulin levels were identified from meta-analyses of genome-wide association studies in European populations (GWASs) (N = 151,013). Summary level data for Lp(a) in the population of European ancestry were acquired from a GWAS in the UK Biobank (N = 361,194). The inverse-variance weighted (IVW) method approach was applied to perform two-sample summary-level MR. Robust methods for sensitivity analysis were utilized, such as MR‒Egger, the weighted median (WME) method, MR pleiotropy residual sum and outlier (MR-PRESSO), leave-one-out analysis, and MR Steiger.ResultsGenetically predicted fasting insulin levels were negatively associated with Lp(a) levels (β = − 0.15, SE = 0.05, P = 0.003). The sensitivity analysis revealed that WME (β = − 0.26, SE = 0.07, P = 0.0002), but not MR‒Egger (β = − 0.22, SE = 0.13, P = 0.11), supported a causal relationship between genetically predisposed insulin levels and Lp(a).ConclusionOur MR study provides robust evidence supporting the association between genetically predicted increased insulin concentrations and decreased concentrations of Lp(a). These findings suggest that hyperinsulinaemia, which typically accompanies T2D, can partially explain the inverse relationship between low Lp(a) concentrations and an increased risk of T2D.

Branched-Chain and Aromatic Amino Acids, Type 2 Diabetes, and Cardiometabolic Risk Factors among Puerto Rican Adults.

(1) Background: Branched-chain and aromatic amino acids (BCAAs/AAAs) have been considered as markers of type 2 diabetes (T2D); however, studies on associations between these metabolites and T2D and cardiometabolic traits in Hispanic populations are limited. The aim of this study was to examine the associations between baseline BCAAs (isoleucine, leucine, valine)/AAAs (phenylalanine, tyrosine) and prevalent and incident T2D, as well as baseline and longitudinal (2 year) changes in cardiometabolic traits (measures of glycemia, dyslipidemia, inflammation, and obesity) in two large cohorts of adults of Puerto Rican descent. (2) Methods: We included participants of the Boston Puerto Rican Health Study (BPRHS, n = 670) and San Juan Overweight Adult Longitudinal study (SOALS, n = 999) with available baseline metabolite and covariate data. T2D diagnosis was defined based on American Diabetes Association criteria. Multivariable logistic (for baseline T2D), Poisson (for incident T2D), and linear (for cardiometabolic traits) regression models were used; cohort-specific results were combined in the meta-analysis and adjusted for multiple comparisons. (3) Results: Higher baseline BCAAs were associated with higher odds of prevalent T2D (OR1SD BCAA score = 1.46, 95% CI: 1.34-1.59, p < 0.0001) and higher risk of incident T2D (IRR1SD BCAA score = 1.24, 95% CI: 1.13-1.37, p < 0.0001). In multivariable longitudinal analysis, higher leucine and valine concentrations were associated with 2-year increase in insulin (beta 1SD leucine = 0.37 mcU/mL, 95% CI: 0.11-0.63, p < 0.05; beta 1SD valine = 0.43 mcU/mL, 95% CI: 0.17-0.68, p < 0.01). Tyrosine was a significant predictor of incident T2D (IRR = 1.31, 95% CI: 1.09-1.58, p < 0.05), as well as 2 year increases in HOMA-IR (beta 1SD tyrosine = 0.13, 95% CI: 0.04-0.22, p < 0.05) and insulin concentrations (beta 1SD tyrosine = 0.37 mcU/mL, 95% CI: 0.12-0.61, p < 0.05). (4) Conclusions: Our results confirmed the associations between BCAAs and prevalent and incident T2D, as well as concurrent measures of glycemia, dyslipidemia, and obesity, previously reported in predominantly White and Asian populations. Baseline leucine, valine, and tyrosine were predictors of 2 year increases in insulin, whereas tyrosine was a significant predictor of deteriorating insulin resistance over time. Our study suggests that BCAAs and tyrosine could serve as early markers of future glycemic changes in Puerto Ricans.

Effect of intermittent hypoxia on glucose tolerance in adults with type 2 diabetes

Hypoxia stimulates glucose uptake through an insulin-independent pathway. The purpose of this single-blind randomized study was to determine the acute effect of intermittent hypoxia, consisting of alternating short bouts of breathing hypoxic and normoxic air, on glucose and insulin concentrations during an oral glucose tolerance test in adults with type 2 diabetes. It was hypothesized that intermittent hypoxia would attenuate the increase in glucose and insulin concentrations during an oral glucose tolerance test. Six adults with type 2 diabetes (5 men, age: 51±15 years, HbA1c: 7.3±1.5%) visited the laboratory on two occasions. On both visits, a 2-hour oral glucose tolerance test was performed, with venous blood samples collected 0, 30, 60, 90, and 120 min after ingestion of a high-glucose drink. Following ingestion of the drink, participants were exposed to either an intermittent hypoxia (IH) protocol, consisting of eight 4-min hypoxic cycles at a targeted arterial oxygen saturation of 80% interspersed with breathing room air to resaturation, or an intermittent normoxia (IN) protocol consisting of eight 4-min normoxic cycles interspersed with breathing room air. By design, oxygen saturation was lower during intermittent hypoxia than intermittent normoxia (81±3 vs. 97±1%, p&lt;0.01). Relative changes in plasma glucose concentrations in response to the oral glucose tolerance tests were not different between conditions (IH vs. IN: 30: 42±15 vs. 35±15; 60: 57±26 vs. 65±30; 90: 73±32 vs. 88±30; and 120: 78±26 vs. 83±29 mg/dl, interaction effect: p=0.13). Similarly, the relative changes in insulin concentrations in response to the oral glucose tolerance tests were not different between conditions (IH vs. IN: 30: 14±17 vs. 25±17; 60: 42±36 vs. 48±35; 90: 70±58 vs. 86±60; and 120: 103±72 vs. 125±94 ulU/ml, main effect for condition: p=0.12). While these preliminary results did not reach statistical significance, the observed trends for reduced glucose concentrations in combination with lower insulin concentrations during intermittent hypoxia suggest that short bouts of hypoxia improve glucose tolerance by stimulating glucose uptake independently from the action of insulin. Data from a larger sample size of adults with type 2 diabetes are needed to confirm these preliminary findings. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Proinflammatory cytokines suppress nonsense-mediated RNA decay to impair regulated transcript isoform processing in pancreatic β cells.

Proinflammatory cytokines are implicated in pancreatic ß cell failure in type 1 and type 2 diabetes and are known to stimulate alternative RNA splicing and the expression of nonsense-mediated RNA decay (NMD) components. Here, we investigate whether cytokines regulate NMD activity and identify transcript isoforms targeted in ß cells. A luciferase-based NMD reporter transiently expressed in rat INS1(832/13), human-derived EndoC-ßH3, or dispersed human islet cells is used to examine the effect of proinflammatory cytokines (Cyt) on NMD activity. The gain- or loss-of-function of two key NMD components, UPF3B and UPF2, is used to reveal the effect of cytokines on cell viability and function. RNA-sequencing and siRNA-mediated silencing are deployed using standard techniques. Cyt attenuate NMD activity in insulin-producing cell lines and primary human ß cells. These effects are found to involve ER stress and are associated with the downregulation of UPF3B. Increases or decreases in NMD activity achieved by UPF3B overexpression (OE) or UPF2 silencing raise or lower Cyt-induced cell death, respectively, in EndoC-ßH3 cells and are associated with decreased or increased insulin content, respectively. No effects of these manipulations are observed on glucose-stimulated insulin secretion. Transcriptomic analysis reveals that Cyt increases alternative splicing (AS)-induced exon skipping in the transcript isoforms, and this is potentiated by UPF2 silencing. Gene enrichment analysis identifies transcripts regulated by UPF2 silencing whose proteins are localized and/or functional in the extracellular matrix (ECM), including the serine protease inhibitor SERPINA1/α-1-antitrypsin, whose silencing sensitizes ß-cells to Cyt cytotoxicity. Cytokines suppress NMD activity via UPR signaling, potentially serving as a protective response against Cyt-induced NMD component expression. Our findings highlight the central importance of RNA turnover in ß cell responses to inflammatory stress.

Effects of Restraint Stress on Circulating Corticosterone and Met Enkephalin in Chickens: Induction of Shifts in Insulin Secretion and Carbohydrate Metabolism.

This study examined the effects of acute restraint stress in the presence or absence of naltrexone on the circulating concentrations of insulin, glucose, Met-enkephalin and corticosterone in 14-week-old chickens [design: 2 sex × 2 stress/non-stress × 2 +/- naltrexone]. In chickens (five male and five females per treatment) subjected to restraint for 30 min, there were increases in the plasma concentrations of corticosterone and Met-enkephalin. The plasma concentrations of insulin and glucose were also increased in the chickens during restraint. Moreover, there were increases in the plasma concentrations of insulin and glucose in the chickens. The patterns of expression of the proenkephalin gene (PENK) in both the anterior pituitary gland and the adrenal gland were very similar to that of plasma Met-enkephalin. There were relationships between the plasma concentrations of corticosterone, Met-enkephalin, insulin and glucose after 30 min of restraint. The effects of naltrexone treatment on both untreated and stressed chickens were also examined, with naltrexone attenuating the stress-induced increases in the plasma concentrations of corticosterone, Met-enkephalin and glucose but not in those of insulin. The present study demonstrates that stress increases insulin secretion in chickens but also induces insulin resistance.

Comparison of the anti-diabetic effects of various grain and legume extracts in high-fat diet and streptozotocin-nicotinamide-induced diabetic rats

The anti-diabetic properties of whole groats and dietary fibers from various grains and legumes are well known. Nevertheless, studies on the anti-diabetic effects of their extracts are limited, and it is difficult to compare their efficacy. This study investigated the anti-diabetic potential of ethanol extracts from oats (OE), sorghum (SE), foxtail millet (FE), proso millet (PE), adzuki bean (AE), and black soybean (BE) in a high-fat diet and streptozotocin-nicotinamide-induced diabetic rat models. The extracts, obtained using 99.9 % ethanol, were orally administered to diabetic rats for four weeks. Various parameters were evaluated, including fasting blood glucose levels, glucose tolerance, insulin sensitivity, serum insulin levels, and pancreas histological analysis. OE and SE effectively reduced fasting blood glucose levels and the area under the curve (AUC) in the oral glucose tolerance test. Only OE significantly decreased the AUC in the insulin tolerance test and increased insulin concentration and homeostatic model assessment of the β-cell function index, indicating improved insulin sensitivity and β-cell function. Histological and immunohistochemical analysis of the pancreas supported these findings, demonstrating that OE protected against pancreatic cell damage. In contrast, FE, PE, AE, and BE did not have a significant effect on diabetes-related parameters. These findings identify OE as the most promising natural intervention for diabetes management.

Effects of Extracellular Vesicles Derived from Human Umbilical Cord Blood Mesenchymal Stem Cells on Cell Immunity in Nonobese Mice.

Autoimmune responses are the most important pathogenic mechanisms underlying type 1 diabetes (T1D). Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have immunomodulatory effects. In this study, we investigated whether EVs derived from human umbilical cord MSCs (HucMSC-EVs) have treatment effects on nonobese diabetic (NOD) mice as model of T1D. HucMSC-EVs were isolated from human umbilical cord MSCs and characterized. NOD mice (aged 4 weeks) were administered with HucMSC-EVs or the same volume of phosphate-buffered saline (PBS) via caudal vein injection twice per week. After 8 weeks of treatment, blood, spleen, and pancreatic samples were collected. Mouse blood glucose levels and body weights were measured during treatment, and insulin concentration and inflammatory cytokine levels were analyzed by enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) staining were used to evaluate pathological changes in mouse islets. T lymphocyte subsets were evaluated by flow cytometry, while quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) analyses were used to detect the expression of transcription factor and inflammatory cytokines. Our data indicated that HucMSC-EVs treatment reduced blood glucose levels and increased insulin concentration in NOD mice. Levels of interleukin-2 (IL-2), IL-4, and IL-10 were significantly increased and those of IL-1β and interferon-γ (IFN-γ) significantly decreased in the HucMSC-EVs group. The positive ratio of CD4+ T lymphocyte subsets decreased after intravenous injection of HucMSC-EVs, in which the proportion of Th2 cells increased and that of Th1 decreased. GATA-3 and IL-2, IL-4 and IL-10 expression levels were upregulated in spleen on treatment with HucMSC-EVs, whereas those of T-bet and IFN-γ were downregulated. In addition, more inflammatory cell infiltration was detected in the pancreas of control group mice than those treated with HucMSC-EVs. IHC staining showed that Fas/FasL expression and distribution in control group pancreas were higher than those in the HucMSC-EVs group. Together, our findings indicate that HucMSC-EVs have potential to prevent islet injury via T cell immune responses by adjusting the Th1/Th2 ratio to regulate secretion of inflammatory factors.

FXR controls insulin content by regulating Foxa2-mediated insulin transcription

Farnesoid X receptor (FXR) is a nuclear ligand-activated receptor of bile acids that plays a role in the modulation of insulin content. However, the underlying molecular mechanisms remain unclear. Forkhead box a2 (Foxa2) is an important nuclear transcription factor in pancreatic β-cells and is involved in β-cell function. We aimed to explore the signaling mechanism downstream of FXR to regulate insulin content and underscore its association with Foxa2 and insulin gene (Ins) transcription. All experiments were conducted on FXR transgenic mice, INS-1 823/13 cells, and diabetic Goto-Kakizaki (GK) rats undergoing sham or Roux-en-Y gastric bypass (RYGB) surgery. Islets from FXR knockout mice and INS-1823/13 cells with FXR knockdown exhibited substantially lower insulin levels than that of controls. This was accompanied by decreased Foxa2 expression and Ins transcription. Conversely, FXR overexpression increased insulin content, concomitant with enhanced Foxa2 expression and Ins transcription in INS-1 823/13 cells. Moreover, FXR knockdown reduced FXR recruitment and H3K27 trimethylation in the Foxa2 promoter. Importantly, Foxa2 overexpression abrogated the adverse effects of FXR knockdown on Ins transcription and insulin content in INS-1 823/13 cells. Notably, RYGB surgery led to improved insulin content in diabetic GK rats, which was accompanied by upregulated FXR and Foxa2 expression and Ins transcription. Collectively, these data suggest that Foxa2 serves as the target gene of FXR in β-cells and mediates FXR-enhanced Ins transcription. Additionally, the upregulated FXR/Foxa2 signaling cascade could contribute to the enhanced insulin content in diabetic GK rats after RYGB.

The Effect of Intermittent Fasting and Caloric Restricted Diet on Diabetic Rats

The present study was aimed to investigate the effect of intermittent fasting and caloric restricted diet (RD) for 8 weeks on diabetic rats. Forty-nine adult male albino rats were divided into two main groups; the first main group was fed only on basal diet and served as negative control group and the second main group: diabetic rats were induced by a single intra-peritoneal injection of freshly prepared STZ (60 mg/kg BW) then divided into 6 subgroups: Subgroup (1) was fed only on basal diet and was served as positive cont. Subgroup (2) was fed on RD only. Subgroups (3, 4) were fed on basal diet and were deprived of food except water from 5 p.m. to 8 a.m. twice a week and every other day, respectively. Subgroups (5, 6): were fed on RD and intermittent fasting twice a week and every other day, respectively. The results indicated that RD and intermittent fasting significantly decreased the final body weight, feed intake and body weight gain % values as compared to the positive control rats. Diabetic treated rats had significant increase (p&lt;0.05) in insulin concentration and lower glucose levels as well as an improvement in liver functions and lipid profile as compared to the positive control group. Conclusion: the findings suggest that intermittent fasting and caloric restricted diet could have a potential role in managing diabetes.

The effect of maternal organic manganese supplementation on performance, immunological status, blood biochemicaland antioxidant status of Afshari ewes and their newborn lambs in transition period.

It has been documented that adequate maternal manganese (Mn) status is vital for performance and health of ewes and their newborn lambs. However, required level and form of dietary Mn in ruminants are not well defined. The current study was conducted to evaluate the effect of maternal organic Mn supplementation on performance, immunological status, blood biochemicaland antioxidant status of Afshari ewes and their newborn lambs in transition period. For this purpose, various organic Mn concentrations were utilized as a supplementary ingredient in formulating the diets of ewes. The ewes were randomly allocated into three groups, fed with 0, and 80 mg/kg organic Mn supplemented diet. At the end of the experiment, the parameters including the performance of newborn lambs, as well as biochemical factors, immune statusand antioxidant status in ewes and their newborn lambs were evaluated. The results showed a significant increase in the plasma concentrations of Mn, glucose, insulin, thyroid hormones (T3 , T4 )and enzymatic antioxidants (SOD, GPX , CAT) in ewes and their newborn lambs that were treated with maternal organic Mn. Moreover, inorganic Mn treatments, the concentration of IgG in newborn lamb's plasma, and colostrum of ewes increased. According to this research, organic Mn acts as a valuable and safe supplementary material that could be exploited for enhancing health of ewes and their newborn lambs.

Diagnosis of equine endocrinopathies: The value of measuring blood glucose during an oral glucose test

Blood glucose concentration is often measured during an oral glucose test (OGT), but is not thought to aid in diagnosing insulin dysregulation (ID) or pituitary pars intermedia dysfunction (PPID). The aim of this retrospective study was to investigate whether the change in blood glucose concentration during an OGT aligned with indicators of equine metabolic syndrome or PPID, including serum insulin and plasma ACTH concentrations, clinical observations, age, sex, breed type and the test dose. The cohort included 149 horses, miniature horses, and ponies that had undergone an in-feed OGT and clinical examination between 2015 and 2021. The animals were diagnosed as either metabolically healthy, insulin-dysregulated, having PPID or both endocrinopathies. The mean ± standard error increase in blood glucose during the OGT was 3.41 ± 0.21 mM, and this change showed a weak positive correlation with the increase in serum insulin concentration (r = 0.36; P 0.001), body condition score (BCS; r = 0.26; P = 0.002) and cresty neck score (CNS; r = 0.38; P 0.001). The median [interquartile range] increase in blood glucose for miniature horses (5.25 [2.98–6.5] mM), was more than twice that seen in full-sized horses (2.4 [1.33–3.45] mM; P = 0.03). In metabolically healthy animals the increase in blood glucose during an OGT (+2.2 [1–3.5] mM) was smaller (P 0.001) than in animals with ID (+3.8 [2.73–5.33] mM), or both endocrine diseases (+6.1 [3.6–6.85] mM). There was an effect of the dose of dextrose on the blood glucose response, with higher doses yielding larger responses (P 0.001). The variability in these data support that basal and post-prandial blood glucose responses to an OGT are not appropriate as stand-alone diagnostic markers of ID or PPID. However, the association between blood glucose and CNS supports the use of CNS when evaluating animals for ID.

Chronic periodontitis induces the proliferation of pancreatic β-cells to cause hyperinsulinemia in a rat model.

The purpose of this study was to determine if chronic periodontitis (CP) may induce hyperinsulinemia and may have the effect of on pancreatic β-cell proliferation in a rat model. Twelve male Sprague-Dawley rats were divided into two groups: the CP group and the control group (Con group). The following contents were evaluated: pathological changes in periodontal soft and hard tissues; serum lipopolysaccharide (LPS) level, serum fasting insulin (FINS) level, fasting blood glucose (FBG) level, and homeostasis model assessment (HOMA) β (HOMA-β) index; histopathological examination of islets; immunohistochemistry of insulin and p-Smad2 expression in islets; immunofluorescence of changes in the relative number of β-cells and the number of Ki67-positive β-cells. Western blotting was used to analyze p-Smad2/Smad2 levels. Results were analyzed by two independent samples t tests. Increased serum LPS level, FINS level, and HOMA-β index were observed in the rats of the CP group; FBG level did not change significantly; histological assessments showed an enlarged islet area, increased insulin content, relatively increased β-cells, increased Ki67-positive β-cells, and decreased p-Smad2 expression in islets in the rats of the CP group. Our study results link CP-induced hyperinsulinemia with changes in islets, such as islet hyperplasia and compensatory β-cell proliferation, by using a CP rat model.

Intra-articular triamcinolone acetonide injection results in increases in systemic insulin and glucose concentrations in horses without insulin dysregulation.

Corticosteroids are a commonly used, inexpensive intra-articular treatment for osteoarthritis which may increase the risk for laminitis in horses due, in part, to hyperinsulinaemia. Humans with metabolic syndrome experience increases in insulin and glucose concentrations post-injection, but responses in horses are unknown. To determine the effect of a single intra-articular (IA) dose of triamcinolone acetate (TA) on blood insulin and glucose concentrations. Before-after study. Ten horses with normal insulin regulation as assessed by an oral sugar test received 18 mg of TA into one middle carpal joint. Insulin and glucose concentrations were evaluated at baseline and 4, 6, 8, 24, 48, and 72 h following IA corticosteroid injection. Differences from baseline were evaluated using a repeated measures ANOVA with Dunnett's multiple comparison testing or a Friedman test with Dunn's correction (significant at p < 0.05). Mean ± SD blood insulin concentration post IA TA injection was increased at 6 h (15.8 ± 3.1 μIU/mL, p = 0.01), 24 h (23 ± 5.8 μIU/mL, p ≤ 0.001), and 48 h (29 ± 13 μIU/mL, p ≤ 0.01) compared to baseline (10 ± 12.3 μIU/mL), with the peak at 48 h. Median ± 95% CI blood glucose concentration post IA TA injection was increased at 6 h (112.7 ± 20.3 mg/dL, p = 0.006), 8 h (112.9 ± 21.4 mg/dL, p = 0.004), 24 h (122.6 ± 14.6, p ≤ 0.0001), and 48 h (123.5 ± 15.4 mg/dL, p ≤ 0.0001) compared to baseline (89.2 ± 6.6 mg/dL), with the peak at 48 h. Only horses with normal insulin regulation were evaluated. Blood insulin and glucose concentrations modestly increased for 48 h following IA TA.

Labor division of worker ants can be controlled by insulin synthesis targeted through miR-279c-5p in Solenopsis invicta (Hymenoptera: Formicidae).

In social insects, the labor division of workers is ubiquitous and controlled by genetic and environmental factors. However, how they modulate this coordinately remains poorly understood. We report miR-279c-5p participation in insulin synthesis and behavioral transition by negatively regulating Rab8A in Solenopsis invicta. Eusocial specific miR-279c-5p is age-associated and highly expressed in nurse workers, and localized in the cytoplasm of neurons, where it is partly co-localized with its target, Rab8A. We determined that miR-279c-5p agomir suppressed Rab8A expression in forager workers, consequently decreasing insulin content, resulting in the behavioral shift to 'nurse-like' behaviors, while the decrease in miR-279c-5p increased Rab8A expression and increased insulin content in nurse workers, leading to the behavioral shift to 'foraging-like' behaviors. Moreover, insulin could rescue the 'foraging behavior' induced by feeding miR-279c-5p to nurse workers. The overexpression and suppression of miR-279c-5p in vivo caused an obvious behavioral transition between foragers and nurses, and insulin synthesis was affected by miR-279c-5p by regulating the direct target Rab8A. We first report that miR-279c-5p is a novel regulator that promotes labor division by negatively regulating the target gene Rab8A by controlling insulin production in ants. This miRNA-mediated mechanism is significant for understanding the behavioral plasticity of social insects between complex factors and potentially provides new targets for controlling red imported fire ants. This article is protected by copyright. All rights reserved.