Development Of Glucose Intolerance Research Articles

1578-P: Hyaluronidase-1 Inhibits Hepatic Gluconeogenesis

Hyaluronidase-1 (Hyal1) is a lysosomal hyaluronidase that intracellularly hydrolyzes hyaluronan (HA). Studies have demonstrated the critical role of Hyal1 in the development of diabetes-induced endothelium dysfunction. However, whether it plays a role in the development of glucose intolerance and obesity remains unclear. We treated Hyal1 whole-body knockout (Hyal1 KO) mice and liver specific overexpression (OE) of Hyal1 mice with a low-fat diet (LFD) or high-fat diet (HFD), Hyal1 KO mice gained similar body weight but developed glucose intolerance compared to littermate wildtype (WT) mice on HFD, the latter is primarily contributed by an increase in gluconeogenesis in the Hyal1 KO liver. In contrast, Hepatic OE of Hyal1 suppressed gluconeogenesis. However, the change in gluconeogenesis is unlikely mediated by digestion of extracellular HA by Hyal1 in the liver as albumin-driven expression of a more potent hyaluronidase Ph20 had no effect on glucose tolerance nor gluconeogenesis from pyruvate. Liver metabolites in the gluconeogenesis pathway were significantly increased by HFD, whereas this was significantly attenuated in hepatic Hyal1-OE mice. Glucose transportersGLUT1 and GLUT2 were not affected by Hyal1 OE. Hyal1 deletion does not affect overall gene expression, as revealed by mRNA-sequencing of liver. However, ATP generation measured by OCR before and after inhibiting ATPase is decreased in hepatocytes OE of Hyal1, which likely contributes to the reduced energy-consuming gluconeogenesis process in Hyal1 overexpressing hepatocytes. In summary, Hyal1 regulates gluconeogenesis independent of changes in extracellular HA content, gene expression, or glucose transporter abundance in hepatocytes. Reduced gluconeogenesis is likely due to the reprogramming of intracellular metabolism and a reduction in ATP production through a remain-to-understand lysosome to mitochondria crosstalk. Disclosure X.Chen: None. Y.Zhu: None. Funding U.S. Department of Agriculture-Agricultural Research Service (3092-51000-062)

75-OR: Cold-Responsive Proteolytic Rewiring of Mitochondria Safeguards White Fat Thermogenic Remodeling

Mitochondrial proteases are emerging as key regulators of mitochondrial plasticity acting both as protein quality surveillance and regulatory enzymes. It remains unclear, however, whether the regulated mitochondrial proteolysis is mechanistically linked to cell identity switch such as white-to-beige conversion of adipocytes. Here we report that cold-responsive mitochondrial proteolysis is a prerequisite for conversion from white-to-beige adipocytes during white adipose tissue (WAT) browning. MitoTimer reporter and chemical thiol probe analysis reveal that thermogenic stimulation selectively promotes mitochondrial proteostasis in WAT via mitochondrial protease LONP1 both in vivo and in vitro. Disruption of LONP1-dependent proteolysis substantially impairs cold or b3-AR agonist induced adipocyte identity programming, evidenced by the remarkably attenuated formation of UCP1+ multilocular adipocytes in IWAT from Lonp1 f/f/Adipoq-Cre (LONP1 AKO) mice. LONP1 AKO mice exposed to cold had lower body temperature, elevated serum TG and FFA levels. Chow-fed LONP1 AKO mice also developed glucose intolerance. “AdipoChaser” system “pulse-chase” lineage tracing experiments confirm that LONP1 ablation markedly blocks the direct cell fate programming of pre-existing mature adipocytes. Importantly, augmented LONP1 expression corrects aging-related impairments in white-to-beige adipocytes conversion. 10-month-old adipocyte-specific Lonp1 overexpression mice had significantly lower body weight and fat mass as a result of elevated energy expenditure. Thus, the identification of LONP1 as a critical safeguard of WAT beiging holds promise for translational applications in enhancing white-to-beige adipocytes conversion capacity relevant to a variety of metabolic disease states and during aging. Disclosure T.Fu: None. W.Sun: None. Z.Zhou: None. Z.Xu: None. M.Yan: None. L.Yang: None. Y.Yin: None. Z.Gan: None.

Maternal low-calorie sweetener consumption rewires hypothalamic melanocortin circuits via a gut microbial co-metabolite pathway.

The prevalence of obesity and type 2 diabetes is growing at an alarming rate, including among pregnant women. Low-calorie sweeteners (LCSs) have increasingly been used as an alternative to sugar to deliver a sweet taste without the excessive caloric load. However, there is little evidence regarding their biological effects, particularly during development. Here, we used a mouse model of maternal LCS consumption to explore the impact of perinatal LCS exposure on the development of neural systems involved in metabolic regulation. We report that adult male, but not female, offspring from both aspartame- and rebaudioside A-exposed dams displayed increased adiposity and developed glucose intolerance. Moreover, maternal LCS consumption reorganized hypothalamic melanocortin circuits and disrupted parasympathetic innervation of pancreatic islets in male offspring. We then identified phenylacetylglycine (PAG) as a unique metabolite that was upregulated in the milk of LCS-fed dams and the serum of their pups. Furthermore, maternal PAG treatment recapitulated some of the key metabolic and neurodevelopmental abnormalities associated with maternal LCS consumption. Together, our data indicate that maternal LCS consumption has enduring consequences on the offspring's metabolism and neural development and that these effects are likely to be mediated through the gut microbial co-metabolite PAG.

The utility of plasma glycated CD59 in predicting postpartum glucose intolerance: a prospective study of women diagnosed with GDM during a period of universal GDM screening.

Gestational diabetes (GDM) is associated with the development of postpartum (PP) glucose intolerance. Plasma glycated CD59 (pGCD59) is an emerging biomarker for the detection of hyperglycaemia. The aim of this study was to assess the ability of PP pGCD59 to predict the development of PP GI as defined by the 2h 75 g OGTT using the ADA criteria, in a cohort of women diagnosed with prior GDM in the index pregnancy using the 2h 75 g OGTT at 24-28 weeks of gestation according to the World Health Organisation (WHO) 2013 criteria METHODS: Of the 2017 pregnant women recruited prospectively 140 women with gestational diabetes had samples for pGCD59 taken PP at the time of the OGTT. The ability of pGCD59 to predict the results of the PP OGTT was assessed using nonparametric receiver operating characteristic (ROC) curves. Women with PP glucose intolerance had significantly higher PP pGCD59 levels compared to women with normal glucose tolerance PP (3.8 vs 2.7 SPU). PP pGCD59 identified women who developed glucose intolerance PP with an AUC of 0.80 (95% CI:0.70-0.91). A PP pGCD59 cut-off value of 1.9 SPU generated a sensitivity of 100% (95%CI:83.9-100), specificity of 16.9% (95%CI:9.8-26.3), positive predictive value of 22.1% (95%CI:21.0-22.6), and negative predictive value of 100% (95%CI:87.4-100). PP fasting plasma glucose generated an AUC of 0.96 (95%CI:0.89-0.99) for the identification of PP glucose intolerance. Our study found that PP pGCD9 may be a promising biomarker to identify women not requiring PP glucose intolerance screening using the traditional OGTT. While the diagnostic accuracy of pGCD59 is good, fasting plasma glucose remains a better test for the identification of PP glucose intolerance.

Diet-Induced Obese Male Mice Treated with a Rationally Designed P450 8B1 Inhibitor for 28 Days Successfully Increased CDCA to CA Ratios but Lacked Improved Glucose Tolerance and Body Weight

Altering the bile acid composition by inhibiting cytochrome P450 8B1 enzyme (CYP8B1) activity results in a decrease in the production of cholic acid (CA, 12α-hydroxylated bile acids) while increasing chenodeoxycholic acid (CDCA). Previous studies have shown that knocking out the Cyp8b1 gene in mice protects against diet-induced obesity and improves glucose tolerance and fat deposition in the liver. The objective of this study was to test the hypothesis that the inhibition of P450 8B1 enzyme activity with a rationally designed small molecule drug would alleviate diet-induced obesity and improve metabolic health. Male C57BL/6J mice (8-10 weeks old) were fed a high-fat and high sucrose (HF) diet over 10 weeks. When mice in the HF group were obese and developed glucose intolerance, half of the mice were treated with P450 8B1 inhibitor (HF/D), and the other half were treated with vehicle (HF/V, 20% β-hydroxypropyl cycolodextrin in the PBS). Mice fed a low fat and low sucrose diet treated with vehicle were used as a reference control (LF/V). Mice in the HF/D group were treated with 100 mg/kg/day, while mice in the vehicle groups (HF/V and LF/V) were administered with the same volume of vehicle. All mice were treated at the same time each morning by oral gavage for 28 days. Bodyweight and food intake were measured weekly. Glucose (GTT)- and insulin tolerance (ITT) tests were conducted before treatment and after treatment. Stool samples were extracted to measure the amount of CDCA and CA by high-resolution mass spectrometry. We found that the HF/D group did not have altered body weight, food intake, and fat composition compared to the HF/V group for the duration of the treatment (28 days). In addition, the HF/D group did not show any improvement in GTT and ITT during the 28 days of treatment. Despite these results related to body weight, GTT, and ITT, the stool samples from the HF/D group generally had a larger ratio of CDCA to CA compared to the HF/V group (CDCA/CA ratios for HF/D vs. HF/V were: 5.5, 9.4, 2.7, 4.1, 3.3 vs. 0.5, 1.5, 2.2, 8.4), suggesting that the inhibition of P450 8B1 did occur in the HFD group. The lipid droplet in the liver also decreased in some mice treated in the HF/D group. Our results suggest that a newly designed inhibitor that has a higher affinity towards the P450 8B1 enzyme relative to our originally designed inhibitor may reduce fatty liver diseases by modifying bile acid composition more effectively. Alternatively, future studies are warranted where the HF mice will be treated for a duration longer than 28 days to check whether the CDCA/CA ratio matches the physiological alterations including body weight and glucose homeostasis. This study was supported by the National Institute of Health [NIH, NIGMS, grant GM125603] to E. Chung This is the full abstract presented at the American Physiology Summit 2023 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.

Hepatic leucine carboxyl methyltransferase 1 (LCMT1) contributes to high fat diet-induced glucose intolerance through regulation of glycogen metabolism

Impaired glucose regulation is one of the most important risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which have become a major public health issue worldwide. Dysregulation of carbohydrate metabolism in liver has been shown to play a critical role in the development of glucose intolerance but the molecular mechanism has not yet been fully understood. In this study, we investigated the role of hepatic LCMT1 in the regulation of glucose homeostasis using a liver-specific LCMT1 knockout mouse model. The hepatocyte-specific deletion of LCMT1 significantly upregulated the hepatic glycogen synthesis and glycogen accumulation in liver. We found that the liver-specific knockout of LCMT1 improved high fat diet-induced glucose intolerance and insulin resistance. Consistently, the high fat diet-induced downregulation of glucokinase (GCK) and other important glycogen synthesis genes were reversed in LCMT1 knockout liver. In addition, the expression of GCK was significantly upregulated in MIHA cells treated with siRNA targeting LCMT1 and improved glycogen synthesis. In this study, we provided evidences to support the role of hepatic LCMT1 in the development of glucose intolerance induced by high fat diet and demonstrated that inhibiting LCMT1 could be a novel therapeutic strategy for the treatment of glucose metabolism disorders.

Pathophysiology and Management of Glycemic Alterations before and after Surgery for Pheochromocytoma and Paraganglioma

Glycemic alterations are frequent in patients with pheochromocytoma and paraganglioma (PPGL), but the real incidence of secondary diabetes mellitus (DM) is uncertain, because prospective multicenter studies on this topic are lacking in the literature. The main pathophysiological mechanisms of glucose homeostasis alterations in PPGL, related to catecholamine hypersecretion, are impaired insulin and glucagon-like peptide type 1 (GLP-1) secretion and increased insulin resistance. Moreover, it has been reported that different pathways leading to glucose intolerance may be related to the secretory phenotype of the chromaffin tumor. Predictive factors for the development of glucose intolerance in PPGL patients are a higher age at diagnosis, the need for a higher number of anti-hypertensive drugs, and the presence of secreting neoplasms. Tumor resection is strongly related to the resolution of DM in PPGL patients, with a significant improvement of glycemic control in most cases. We can hypothesize a different personalized therapeutic approach based on the secretory phenotype. The adrenergic phenotype is more closely related to reduced insulin secretion, so insulin therapy may be required. On the other hand, the noradrenergic phenotype mainly acts by increasing insulin resistance and, therefore, insulin-sensitizing antidiabetic agents can find a greater application. Regarding GLP-1 receptor agonists, the data suggest a possible promising therapeutic effect, based on the assumption that GLP-1 secretion is impaired in patients with PPGL. The principal predictors of remission of glycemic alterations after surgery for PPGL are a lower preoperative body mass index (BMI), a larger tumor, higher preoperative catecholamine levels, and a shorter duration of the disease (under three years). Otherwise, after resection of PPGL, hypoglycemia can occur as the result of an excessive rebound of preoperative hyperinsulinemia. It is a rare, but potentially severe complication reported in a lot of case reports and a few small retrospective studies. Higher 24-h urinary metanephrine levels, longer operative times and larger tumors are predictive factors for hypoglycemia in this setting. In conclusion, alterations of carbohydrate metabolism are clinically relevant manifestations of PPGL before and after surgery, but there is the need to conduct multicenter prospective studies to obtain an adequate sample size, and to allow the creation of shared strategies for the clinical management of these potentially severe manifestations of PPGL.

Vertical sleeve gastrectomy associates with airway hyperresponsiveness in a murine model of allergic airway disease and obesity.

Asthma is a chronic airway inflammatory disease marked by airway inflammation, remodeling and hyperresponsiveness to allergens. Allergic asthma is normally well controlled through the use of beta-2-adrenergic agonists and inhaled corticosteroids; however, a subset of patients with comorbid obesity experience resistance to currently available therapeutics. Patients with asthma and comorbid obesity are also at a greater risk for severe disease, contributing to increased risk of hospitalization. Bariatric surgery improves asthma control and airway hyperresponsiveness in patients with asthma and comorbid obesity, however, the underlying mechanisms for these improvements remain to be elucidated. We hypothesized that vertical sleeve gastrectomy (VSG), a model of metabolic surgery in mice, would improve glucose tolerance and airway inflammation, resistance, and fibrosis induced by chronic allergen challenge and obesity. Male C57BL/6J mice were fed a high fat diet (HFD) for 13 weeks with intermittent house dust mite (HDM) allergen administration to induce allergic asthma, or saline as control. At week 11, a subset of mice underwent VSG or Sham surgery with one week recovery. A separate group of mice did not undergo surgery. Mice were then challenged with HDM or saline along with concurrent HFD feeding for 1-1.5 weeks before measurement of lung mechanics and harvesting of tissues, both of which occurred 24 hours after the final HDM challenge. Systemic and pulmonary cytokine profiles, lung histology and gene expression were analyzed. High fat diet contributed to increased body weight, serum leptin levels and development of glucose intolerance for both HDM and saline treatment groups. When compared to saline-treated mice, HDM-challenged mice exhibited greater weight gain. VSG improved glucose tolerance in both saline and HDM-challenged mice. HDM-challenged VSG mice exhibited an increase in airway hyperresponsiveness to methacholine when compared to the non-surgery group. The data presented here indicate increased airway hyperresponsiveness in allergic mice undergoing bariatric surgery.

Role of adrenomedullin2/ intermedin in pregnancy induced vascular and metabolic adaptation in mice.

Introduction: Adrenomedullin2 (AM2) shares its receptor with Calcitonin gene related peptide and adrenomedullin with overlapping but distinct biological functions. Goal of this study was to assess the specific role of Adrenomedullin2 (AM2) in pregnancy induced vascular and metabolic adaptation using AM2 knockout mice (AM2 -/-). Method : The AM2 -/- mice were successfully generated using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Nuclease Cas nine system. Phenotype of pregnant AM2 -/- mice was assessed with respect to its fertility, blood pressure regulation, vascular health and metabolic adaptations and compared to the wild type littermates (AM2 +/+). Results : Current data shows that AM2 -/- females are fertile with no significant difference in number of pups/litter compared to the AM2 +/+. However, ablation of AM2 decreases the gestational length and the total number of pups born dead or that die after birth is greater in AM2 -/- mice compared to AM2 +/+ mice (p < 0.05). Further AM2 -/- mice exhibit elevated blood pressure and elevated vascular sensitivity for the contractile responses to angiotensin two and higher serum sFLT-1 trigylcerides levels compared to AM2 +/+(p < 0.05). In addition, AM2 -/- mice develop glucose intolerance with elevated serum levels of Insulin during pregnancy compared to the AM2 +/+mice. Discussion: Current data suggests a physiological role for AM2 in pregnancy induced vascular and metabolic adaptations in mice.

Fetal growth restriction followed by early catch-up growth impairs pancreatic islet morphology in male rats

Fetal growth restriction (FGR), followed by postnatal early catch-up growth, is associated with an increased risk of metabolic dysfunction, including type 2 diabetes in humans. This study aims to determine the effects of FGR and early catch-up growth after birth on the pathogenesis of type 2 diabetes, with particular attention to glucose tolerance, pancreatic islet morphology, and fibrosis, and to elucidate its mechanism using proteomics analysis. The FGR rat model was made by inducing mild intrauterine hypoperfusion using ameroid constrictors (ACs). On day 17 of pregnancy, ACs were affixed to the uterine and ovarian arteries bilaterally, causing a 20.9% reduction in birth weight compared to sham pups. On postnatal day 4 (P4), the pups were assigned to either the good nutrition (GN) groups with 5 pups per dam to ensure postnatal catch-up growth or poor nutrition groups with 15 pups per dam to maintain lower body weight. After weaning, all pups were fed regular chow food ad libitum (P21). Rats in both FGR groups developed glucose intolerance; however, male rats in the FGR good nutrition (FGR-GN) group also developed hypertriglyceridemia and dysmorphic pancreatic islets with fibrosis. A comprehensive and functional analysis of proteins expressed in the pancreas showed that FGR, followed by early catch-up growth, severely aggravated cell adhesion-related protein expression in male offspring. Thus, FGR and early catch-up growth caused pancreatic islet morphological abnormalities and fibrosis associated with the disturbance of cell adhesion-related protein expressions. These changes likely induce glucose intolerance and dyslipidemia in male rats.

A Review on the Role of Low Glycemic Index Foods for Glycemic Control in Chronic Liver Disease

Liver is an essential organ that maintains fasting and postprandial blood glucose response via various metabolic pathways. The liver function gradually deteriorates in chronic liver disease (CLD) due to inflammation and destruction of liver parenchyma. The development of glucose intolerance and hepatogenous diabetes (HD) in patients with CLD is an inevitable event. Diabetes and CLD can coexist, and function synergistically to cause unfavorable clinical consequences, including poor treatment outcomes and frequent hospitalization. The complications associated with liver disease (malnutrition, hypoglycemia, acute kidney injury, lactic acidosis, etc.) and lack of guidelines limit pharmacological management of HD. Dietary recommendations by The European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines (2019), suggested weight reducing hypocaloric diet along with adequate branched-chain amino acid (BCAA) and micronutrient consumption to improve steatosis and insulin sensitivity in patients with CLD. Dietary glycemic index controls prognosis of obesity, non-alcoholic fatty liver disease (NAFLD) and diabetes. The importance of low GI diet in reducing fasting blood glucose, hepatic glucose influx and fat accumulation, thereby improving weight loss and NAFLD score, is being published in patients with diabetes or liver disease. Several countries have already incorporated GI into their national health policies, for identification of the nutrient value, resulting in establishment of worldwide GI and glycemic load tables for specific food items. However, the apparent complexity of GI and lack of low GI meal choices need to be resolved in order to enhance patient’s quality of life, health and well-being. Low GI nutritional supplements, comprising of balanced proportion of carbohydrate, protein, BCAAs, fibers and micronutrients, may reduce the complexity related to dietary management of HD. The review summarizes the importance of nutritional management in HD with focus on low GI diet in people with CLD.

Preconceptional exposure of adult male rats to bisphenol S impairs insulin sensitivity and glucose tolerance in their male offspring

Since the use of bisphenol A (BPA) has been restricted because of its endocrine disruptor properties, bisphenol S (BPS) has been widely used as a substitute of BPA. However, BPS exerts similar effects on metabolic health as BPA. The effects of maternal exposure to BPA and BPS on the metabolic health of offspring have been largely documented during the past decade. However, the impact of preconceptional paternal exposure to BPS on progenies remains unexplored. In this study we investigated the impact of paternal exposure to BPS before conception, on the metabolic phenotype of offspring. Male Wistar rats were administered BPS through drinking water at the dose of 4 μg/kg/day (BPS-4 sires) or 40 μg/kg/day (BPS-40 sires) for 2 months before mating with females. The progenies (F1) were studied at fetal stage and in adulthood. We showed that preconceptional paternal exposure to BPS for 2 months did not alter the metabolic status of sires. The female offspring of sires exposed to lower or higher doses of BPS showed no alteration of their metabolic phenotype compared to females from control sires. In contrast, male offspring of BPS-4 sires exhibited increased body weight and body fat/lean ratio, decreased insulin sensitivity and increased glucose-induced insulin secretion at adult age, compared to the male offspring of control sires. Moreover, male offspring of BPS-4 sires developed glucose intolerance later in life. None of these effects were apparent in male offspring of BPS-40 sires. In conclusion, our study provides the first evidence of the non-monotonic and sex-specific effects of preconceptional paternal exposure to BPS on the metabolic health of offspring, suggesting that BPS is not a safe BPA substitute regarding the inter-generational transmission of metabolic disorders through the paternal lineage.

Young adult male LEW.1WR1 rats have reduced beta cell area and develop glucose intolerance

Prediabetes affects 1 in 3 American adults and is characterized by insulin resistance, insulin hypersecretion, and impaired glucose tolerance. Weanling LEW.1WR1 (1WR1) rats have increased blood insulin concentrations, so we hypothesized that young adult 1WR1 rats would develop impaired glucose tolerance due to the poor regulation of insulin. We monitored glucose tolerance, insulin tolerance, and weight gain for 10 weeks to assess if there was a decline in glucose processing over time. 1WR1 rats were significantly more glucose intolerant after 8 weeks. 1WR1 rats had increased body mass, yet abdominal fat mass was not significantly increased. Although the 1WR1 rats had increased circulating insulin and glucagon protein levels, 1WR1 rat beta cell area was significantly reduced. There may be underlying insulin resistance as evidenced by dysfunctional insulin regulation during fasting. Understanding the metabolic phenotype of this rat model can provide insight into the human pathophysiological changes that increase susceptibility to glucose intolerance and prediabetes.

Proteomic profiling of exosomes derived from pancreatic beta-cells cultured under hyperglycemia

Abstract Introduction Cargo carried by extracellular vesicles (EVs) is considered a promising diagnostic marker, especially proteins. EVs can be divided according to their size and way of biogenesis into exosomes (diameter &lt; 200 nm) and ectosomes (diameter &gt; 200 nm). Exosomes are considered to be of endocytic origin, and ectosomes are produced by budding and shedding from the plasma membrane [1]. Methods The first step of this study was a characterization of the exosome sample. Using Tunable Resistive Pulse Sensing (qNano) size distribution and concentration were measured. The mean size of exosomes was 120±9.17 nm. In the present study, a nano liquid chromatography coupled with tandem mass spectrometry (nanoLCMS/MS) was used to compare protein profiles of exosomes secreted by pancreatic beta cells (1.1B4) grown under normal glucose (NG, 5 mM D-glucose) and high glucose (HG, 25 mM D-glucose) conditions. The EV samples were lysed, and proteins were denatured, digested, and analyzed using a Q-Exactive mass spectrometer coupled with the UltiMate 3000 RSLC nano system. The nanoLC-MS/MS data were searched against the SwissProt Homo sapiens database using MaxQuant software and protein quantitation was done by the MaxLFQ algorithm. Statistical analysis was carried out with Perseus software. Further bioinformatic analysis was performed using the FunRich 3.1.4 software with the UniProt protein database and String [2]. Results As a result of the nanoLC-MS/MS analysis more than 1,000 proteins were identified and quantified in each sample. The average number of identified proteins in exosomes was 1,397. Label-free quantitative analysis showed that exosome composition differed significantly between those isolated under NG and HG conditions. Many pathways were down-regulated in HG, particularly the ubiquitin-proteasome pathway. In addition, a significant up-regulation of the Ras-proteins pathway was observed in HG. Conclusion Our description of exosomes protein content and its related functions provides the first insight into the EV interactome and its role in glucose intolerance development and diabetic complications. The results also indicate the applicability of EV proteins for further investigation regarding their potential as circulating in vivo biomarkers.

Obesity alters the mouse endometrial transcriptome in a cell context-dependent manner

Obesity impacts fertility and is positively correlated with endometrial hyperplasia and endometrial cancer occurrence. Endometrial epithelia often harbor disease driver-mutations, while endometrial stroma are highly regulative of neighboring epithelia. Here, we sought to determine distinct transcriptome changes occurring in individual cell types in the obese mouse uterus. Outbred CD-1 mice were fed high-fat or control diets for 18 weeks, estrous cycle staged, and endometrial epithelia, macrophages, and stroma isolated for transcriptomic analysis. High-fat diet mice displayed increased body mass and developed glucose intolerance, hyperinsulinemia, and fatty liver. Obese mouse epithelia displayed differential gene expression for genes related to innate immunity and leukocyte chemotaxis. The obese mouse stroma differentially expressed factors related to circadian rhythm, and expression of these genes correlated with glucose tolerance or body mass. We observed correlations between F4/80 + macrophage numbers, Cleaved Caspase 3 (CC3) apoptosis marker staining and glucose intolerance among obese mice, including a subgroup of obese mice with high CC3 + luminal epithelia. This subgroup displayed differential gene expression among all cell types, with pathways related to immune escape in epithelia and macrophages, while the stroma dysregulated pathways related to regulation of epithelia. These results suggest an important role for differential response of both the epithelia and stroma in their response to obesity, while macrophages are dysregulated in the context of apoptotic epithelia. The obesity-related gene expression programs in cells within the uterine microenvironment may influence the ability of the endometrium to function during pregnancy and influence disease pathogenesis.

Insulin sensitivity is preserved in mice made obese by feeding a high starch diet.

Obesity is generally associated with insulin resistance in liver and muscle and increased risk of developing type 2 diabetes, however there is a population of obese people that remain insulin sensitive. Similarly, recent work suggests that mice fed high carbohydrate diets can become obese without apparent glucose intolerance. To investigate this phenomenon further, we fed mice either a high fat (Hi-F) or high starch (Hi-ST) diet and measured adiposity, glucose tolerance, insulin sensitivity, and tissue lipids compared to control mice fed a standard laboratory chow. Both Hi-ST and Hi-F mice accumulated a similar amount of fat and tissue triglyceride compared to chow-fed mice. However, while Hi-F diet mice developed glucose intolerance as well as liver and muscle insulin resistance (assessed via euglycaemic/hyperinsulinaemic clamp), obese Hi-ST mice maintained glucose tolerance and insulin action similar to lean, chow-fed controls. This preservation of insulin action despite obesity in Hi-ST mice was associated with differences in de novo lipogenesis and levels of C22:0 ceramide in liver and C18:0 ceramide in muscle. This indicates that dietary manipulation can influence insulin action independently of the level of adiposity and that the presence of specific ceramide species correlates with these differences.

A novel technique using chronic infusion of small extracellular vesicles from gestational diabetes mellitus causes glucose intolerance in pregnant mice.

Small extracellular vesicles (sEVs) play a central role in cell-to-cell communication in normal physiology and in disease, including gestational diabetes mellitus (GDM). The goal of the present study was to test the hypothesis that chronic administration of sEVs isolated from GDM causes glucose intolerance in healthy pregnant mice. Small EVs were isolated from plasma between 24 and 28 weeks gestation from healthy pregnant women (controls) and GDM, and infused intravenously for 4 days in late pregnant mice using a mini-osmotic pump. Subsequently in vivo glucose tolerance was assessed, and muscle and adipose tissue insulin sensitivity and islet glucose stimulated insulin secretion (GSIS) were determined in vitro. Mice infused with sEVs from GDM developed glucose intolerance. Administration of sEVs from controls, but not sEVs from GDM women, stimulated islet GSIS and increased fasting insulin levels in pregnant mice. Neither infusion of sEVs from controls nor from GDM women affected muscle insulin sensitivity, placental insulin or mTOR signaling, placental and fetal weight. Moreover, these results were not associated with immunomodulatory effects as human sEVs did not activate mouse T cells in vitro. We suggest that circulating sEVs regulate maternal glucose homeostasis in pregnancy and may contribute to the attenuated islet insulin secretion and more pronounced glucose intolerance in GDM as compared with healthy pregnancy.

Selected Articles from This Issue

The overall aims of this study were to describe the association between body composition measures obtained from pre-HCT CT images and early-onset. In this cohort of adults who underwent allogeneic HCT, Bhandari and colleagues found significant associations between body composition measurements obtained from pre-HCT CT imaging studies and early-onset glucose intolerance after HCT. The components of body composition that 10 increased risk for glucose intolerance differed by BMI; in non-overweight patients, skeletal muscle loss increased this risk, while visceral adiposity was associated with increased risk in overweight/obese patients. These findings suggest that multiple mechanisms underlie the development of glucose intolerance and/or DM after HCT and highlight the importance of improving DM risk characterization according to pre-HCT body composition phenotype.Fortunato, Huber, and colleagues, performed peripheral blood high resolution flow cytometry of lung cancer screening volunteers to define an immune classifier discriminating early-stage lung cancer patients from controls. In parallel, a gene signature encompassing the most relevant immune cell subsets defined by the classifier was selected to identify a final diagnostic model. Globally, this immune classifier comprises phenotypic and molecular features of key immune cellular elements such as monocytic and PMN MDSC, intermediate monocytes and activated cytotoxic T cells. By applying a chained-rule simulation approach, the immune classifier was estimated to reduce unnecessary procedures in the 48% of screening participants with a false positive CT result.Menstrual and reproductive factors affected the gender disparity in liver cancer incidence, but the evidence was inconsistent. This study by Tuo and colleagues was the first population-based cohort evaluating the associations between menstrual and reproductive factors and liver cancer risk in Chinese women. The authors found that HRT and injective contraceptives were positively associated with liver cancer risk, while live births' number, menopausal age and reproductive period reduced the risk. The findings suggested that female sex hormones could play roles on liver carcinogenesis, which would be important for the prevention and control of liver cancer.The complex nature of oropharyngeal cancer (OPC), implying a different epidemiological pattern of the subtypes, requires an accurate and timely assessment of the burden of the disease. Accordingly, this study by Lorenzoni and colleagues report an updated overview of the incidence and mortality of OPC worldwide based on GLOBOCAN-2020 estimates. Age-standardized incidence and mortality rates, male-to-female ratios, and incidence-to-mortality ratios were estimated and compared between genders, by country and across world regions. Results highlighted substantial geographical and gender variability, probably related to the different distribution of OPC subtypes. This overview might help guide future studies, support planning and prioritization of prevention and treatment programs.

Chronic treatment with corticosterone increases the number of tyrosine hydroxylase-expressing cells within specific nuclei of the brainstem reticular formation.

Cushing's syndrome is due to increased glucocorticoid levels in the body, and it is characterized by several clinical alterations which concern both vegetative and behavioral functions. The anatomical correlates of these effects remain largely unknown. Apart from peripheral effects induced by corticosteroids as counter-insular hormones, only a few reports are available concerning the neurobiology of glucocorticoid-induced vegetative and behavioral alterations. In the present study, C57 Black mice were administered daily a chronic treatment with corticosterone in drinking water. This treatment produces a significant and selective increase of TH-positive neurons within two nuclei placed in the lateral column of the brainstem reticular formation. These alterations significantly correlate with selective domains of Cushing's syndrome. Specifically, the increase of TH neurons within area postrema significantly correlates with the development of glucose intolerance, which is in line with the selective control by area postrema of vagal neurons innervating the pancreas. The other nucleus corresponds to the retrorubral field, which is involved in the behavioral activity. In detail, the retrorubral field is likely to modulate anxiety and mood disorders, which frequently occur following chronic exposure to glucocorticoids. To our knowledge, this is the first study that provides the neuroanatomical basis underlying specific symptoms occurring in Cushing's syndrome.

Effects of High-dose Folic Acid Supplementation on Maternal/Child Health Outcomes: Gestational Diabetes Mellitus in Pregnancy and Insulin Resistance in Offspring

ObjectivesThe purpose of this study was to evaluate the effects of maternal high folic acid (FA) supplementation during pregnancy on glucose intolerance in dams and insulin resistance in offspring. MethodsWistar female rats (n=18) were mated and randomly divided into 3 groups: a control group and 2 experimental groups. Three different feeding protocols were administered during pregnancy: control group, 2 mg/kg FA (recommended level FA supplementation); experimental 1 group, 5 mg/kg FA (tolerable upper intake level of FA supplementation [ULFolS]); and experimental 2 group, 40 mg/kg FA (high FA supplementation [HfolS]). All dams were fed the same FA content diet (2 mg/kg FA) during the lactation period. An oral glucose tolerance test was performed on day 16 of pregnancy. After the lactation period, body weight and food intake of 36 pups were monitored. Dams were euthanized at the end of the lactation period and half of the pups were euthanized at the end of week 7 and the others at the end of week 12. Serum FA, homocysteine, vitamin B12, insulin, glucose, interleukin-6, tumor necrosis factor-alpha, glycated hemoglobin (A1C), and adiponectin levels of mothers and pups were evaluated. The homeostatic model of insulin resistance (HOMA-IR) was used to determine insulin resistance in dams and offspring. ResultsAccording to glucose tolerance test results of dams, blood glucose values at minutes 0, 60, 90, and 120 for the HFolS group were significantly higher compared with the control group (p<0.05). The A1C level in HFolS dams was significantly higher than in the control group (p<0.05). The mean birthweight of the pups in the HFolS group was significantly higher than that of control pups (p<0.05). HOMA-IR values for control and HFolS offspring were similar at weeks 7 and 12 and higher than in ULFolS offspring (p>0.05). ConclusionsIt was determined that high doses of FA exposure during pregnancy might be effective in the development of glucose intolerance in dams and insulin resistance in offspring in this study.