Maternal Exposure to Bisphenol-A During Pregnancy Increases Pancreatic β-Cell Growth During Early Life in Male Mice Offspring

Alterations during development of metabolic key organs such as the endocrine pancreas affect the phenotype later in life. There is evidence that in utero or perinatal exposure to bisphenol-A (BPA) leads to impaired glucose metabolism during adulthood. However, how BPA exposure during pregnancy affects pancreatic β-cell growth and function in offspring during early life has not been explored. We exposed pregnant mice to either vehicle (control) or BPA (10 and 100 μg/kg·d, BPA10 and BPA100) and examined offspring on postnatal days (P) P0, P21, P30, and P120. BPA10 and BPA100 mice presented lower birth weight than control and subsequently gained weight until day 30. At that age, concentration of plasma insulin, C-peptide, and leptin were increased in BPA-exposed animals in the nonfasting state. Insulin secretion and content were diminished in BPA10 and maintained in BPA100 compared with control. A global gene expression analysis indicated that genes related with cell division were increased in islets from BPA-treated animals. This was associated with an increase in pancreatic β-cell mass at P0, P21, and P30 together with increased β-cell proliferation and decreased apoptosis. On the contrary, at P120, BPA-treated animals presented either equal or decreased β-cell mass compared with control and altered fasting glucose levels. These data suggest that in utero exposure to environmentally relevant doses of BPA alters the expression of genes involved in β-cell growth regulation, incrementing β-cell mass/area, and β-cell proliferation during early life. An excess of insulin signaling during early life may contribute to impaired glucose tolerance during adulthood

Screening of Relevant Metabolism-Disrupting Chemicals on Pancreatic β-Cells: Evaluation of Murine and Human In Vitro Models

Endocrine-disrupting chemicals (EDCs) are chemical substances that can interfere with the normal function of the endocrine system. EDCs are ubiquitous and can be found in a variety of consumer products such as food packaging materials, personal care and household products, plastic additives, and flame retardants. Over the last decade, the impact of EDCs on human health has been widely acknowledged as they have been associated with different endocrine diseases. Among them, a subset called metabolism-disrupting chemicals (MDCs) is able to promote metabolic changes that can lead to the development of metabolic disorders such as diabetes, obesity, hepatic steatosis, and metabolic syndrome, among others. Despite this, today, there are still no definitive and standardized in vitro tools to support the metabolic risk assessment of existing and emerging MDCs for regulatory purposes. Here, we evaluated the following two different pancreatic cell-based in vitro systems: the murine pancreatic β-cell line MIN6 as well as the human pancreatic β-cell line EndoC-βH1. Both were challenged with the following range of relevant concentrations of seven well-known EDCs: (bisphenol-A (BPA), bisphenol-S (BPS), bisphenol-F (BPF), perfluorooctanesulfonic acid (PFOS), di(2-ethylhexyl) phthalate (DEHP), cadmium chloride (CdCl2), and dichlorodiphenyldichloroethylene (DDE)). The screening revealed that most of the tested chemicals have detectable, deleterious effects on glucose-stimulated insulin release, insulin content, electrical activity, gene expression, and/or viability. Our data provide new molecular information on the direct effects of the selected chemicals on key aspects of pancreatic β-cell function, such as the stimulus-secretion coupling and ion channel activity. In addition, we found that, in general, the sensitivity and responses were comparable to those from other in vivo studies reported in the literature. Overall, our results suggest that both systems can serve as effective tools for the rapid screening of potential MDC effects on pancreatic β-cell physiology as well as for deciphering and better understanding the molecular mechanisms that underlie their action.This study received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant agreement no 825712 (OBERON) project. The author’s laboratory also holds grant PID2020-113112RB-I00 funded by MCIN/AEI/10.13039/501100011033. CIBERDEM is an initiative of the Instituto de Salud Carlos III

The Estrogenic Effect of Bisphenol A Disrupts Pancreatic β-Cell Function In Vivo and Induces Insulin Resistance

The function of the pancreatic β-cell is the storage and release of insulin, the main hormone involved in blood glucose homeostasis. The results in this article show that the widespread environmental contaminant bisphenol-A (BPA) imitates 17β-estradiol (E(2)) effects in vivo on blood glucose homeostasis through genomic and nongenomic pathways. The exposure of adult mice to a single low dose (10 μg/kg) of either E(2) or BPA induces a rapid decrease in glycemia that correlates with a rise of plasma insulin. Longer exposures to E(2) and BPA induce an increase in pancreatic β-cell insulin content in an estrogen-receptor–dependent manner. This effect is visible after 2 days of treatment and starting at doses as low as 10 μg/kg/day. After 4 days of treatment with either E(2) or BPA, these mice developed chronic hyperinsulinemia, and their glucose and insulin tolerance tests were altered. These experiments unveil the link between environmental estrogens and insulin resistance. Therefore, either abnormal levels of endogenous estrogens or environmental estrogen exposure enhances the risk of developing type 2 diabetes mellitus, hypertension, and dyslipidemia

Exploring the Effects of Metabolism-Disrupting Chemicals on Pancreatic α-Cell Viability, Gene Expression and Function: A Screening Testing Approach

Humans are constantly exposed to many environmental pollutants, some of which have been largely acknowledged as key factors in the development of metabolic disorders such as diabetes and obesity. These chemicals have been classified as endocrine-disrupting chemicals (EDCs) and, more recently, since they can interfere with metabolic functions, they have been renamed as metabolism-disrupting chemicals (MDCs). MDCs are present in many consumer products, including food packaging, personal care products, plastic bottles and containers, and detergents. The scientific literature has ever-increasingly focused on insulin-releasing pancreatic β-cells as one of the main targets for MDCs. Evidence highlights that these substances may disrupt glucose homeostasis by altering pancreatic β-cell physiology. However, their potential impact on glucagon-secreting pancreatic α-cells remains poorly known despite the essential role that this cellular type plays in controlling glucose metabolism. In the present study, we have selected seven paradigmatic MDCs representing major toxic classes, including bisphenols, phthalates, perfluorinated compounds, metals, and pesticides. By using an in vitro cell-based model, the pancreatic α-cell line αTC1-9, we have explored the effects of these compounds on pancreatic α-cell viability, gene expression, and secretion. We found that cell viability was moderately affected after bisphenol-A (BPA), bisphenol-F (BPF), and perfluorooctanesulfonic acid (PFOS) exposure, although cytotoxicity was relatively low. In addition, all bisphenols, as well as di(2-ethylhexyl) phthalate (DEHP) and cadmium chloride (CdCl2), promoted a marked decreased on glucagon secretion, together with changes in the expression of glucagon and/or transcription factors involved in cell function and identity, such as Foxo1 and Arx. Overall, our results indicated that most of the selected chemicals studied caused functional alterations in pancreatic α-cells. Moreover, we revealed, for the first time, their direct effects on key molecular aspects of pancreatic α-cell biology.This study received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant agreement no. 825712 (OBERON) project and Generalitat Valenciana: PROMETEO/2020/006 grant. The author’s laboratory also holds grant PID2020-113112RB-I00 funded by MCIN/AEI/10.13039/501100011033. CIBERDEM is an initiative of the Instituto de Salud Carlos III

The pancreatic β-cell in ageing: Implications in age-related diabetes

The prevalence of type 2 diabetes (T2D) and impaired glucose tolerance (IGT) increases with ageing. T2D generally results from progressive impairment of the pancreatic islets to adapt fi-cell mass and function in the setting of insulin resistance and increased insulin demand. Several studies have shown an age-related decline in peripheral insulin sensitivity. However, a precise understanding of the pancreatic fi-cell response in ageing is still lacking. In this review, we summarize the age-related alterations, adaptations and/or failures of fi-cells at the molecular, morphological and functional levels in mouse and human. Age-associated alterations include processes such as fi-cell proliferation, apoptosis and cell identity that can influence fi-cell mass. Age-related changes also affect fi-cell function at distinct steps including electrical activity, Ca2+ signaling and insulin secretion, among others. We will consider the potential impact of these alterations and those mediated by senescence pathways on fi-cells and their implications in age-related T2D. Finally, given the great diversity of results in the field of fi-cell ageing, we will discuss the sources of this heterogeneity. A better understanding of fi-cell biology during ageing, particularly at older ages, will improve our insight into the contribution of fi-cells to ageassociated T2D and may boost new therapeutic strategies

Exposure to bisphenol-a during pregnancy partially mimics the effects of a high-fat diet altering glucose homeostasis and gene expression in adult male mice

sem informaçãoBisphenol-A (BPA) is one of the most widespread EDCs used as a base compound in the manufacture of polycarbonate plastics. The aim of our research has been to study how the exposure to BPA during pregnancy affects weight, glucose homeostasis, pancreatic β-cell function and gene expression in the major peripheral organs that control energy flux: white adipose tissue (WAT), the liver and skeletal muscle, in male offspring 17 and 28 weeks old. Pregnant mice were treated with a subcutaneous injection of 10 µg/kg/day of BPA or a vehicle from day 9 to 16 of pregnancy. One month old offspring were divided into four different groups: vehicle treated mice that ate a normal chow diet (Control group); BPA treated mice that also ate a normal chow diet (BPA); vehicle treated animals that had a high fat diet (HFD) and BPA treated animals that were fed HFD (HFD-BPA). The BPA group started to gain weight at 18 weeks old and caught up to the HFD group before week 28. The BPA group as well as the HFD and HFD-BPA ones presented fasting hyperglycemia, glucose intolerance and high levels of non-esterified fatty acids (NEFA) in plasma compared with the Control one. Glucose stimulated insulin release was disrupted, particularly in the HFD-BPA group. In WAT, the mRNA expression of the genes involved in fatty acid metabolism, Srebpc1, Pparα and Cpt1β was decreased by BPA to the same extent as with the HFD treatment. BPA treatment upregulated Pparγ and Prkaa1 genes in the liver; yet it diminished the expression of Cd36. Hepatic triglyceride levels were increased in all groups compared to control. In conclusion, male offspring from BPA-treated mothers presented symptoms of diabesity. This term refers to a form of diabetes which typically develops in later life and is associated with obesity.Bisphenol-A (BPA) is one of the most widespread EDCs used as a base compound in the manufacture of polycarbonate plastics. The aim of our research has been to study how the exposure to BPA during pregnancy affects weight, glucose homeostasis, pancreatic β96113sem informaçãosem informaçãosem informaçã

Low Doses of Bisphenol A and Diethylstilbestrol Impair Ca(2+) Signals in Pancreatic α-Cells through a Nonclassical Membrane Estrogen Receptor within Intact Islets of Langerhans

Glucagon, secreted from pancreatic α-cells integrated within the islets of Langerhans, is involved in the regulation of glucose metabolism by enhancing the synthesis and mobilization of glucose in the liver. In addition, it has other extrahepatic effects ranging from lipolysis in adipose tissue to the control of satiety in the central nervous system. In this article, we show that the endocrine disruptors bisphenol A (BPA) and diethylstilbestrol (DES), at a concentration of 10(−9) M, suppressed low-glucose–induced intracellular calcium ion ([Ca(2+)](i)) oscillations in α-cells, the signal that triggers glucagon secretion. This action has a rapid onset, and it is reproduced by the impermeable molecule estradiol (E(2)) conjugated to horseradish peroxidase (E-HRP). Competition studies using E-HRP binding in immunocytochemically identified α-cells indicate that 17β-E(2), BPA, and DES share a common membrane-binding site whose pharmacologic profile differs from the classical ER. The effects triggered by BPA, DES, and E(2) are blocked by the Gαi- and Gα(o)-protein inhibitor pertussis toxin, by the guanylate cyclase–specific inhibitor 1H-[1,2,4] oxadiazolo[4,3-a] quinoxalin-1-one, and by the nitric oxide synthase inhibitor N-nitro-l-arginine methyl ester. The effects are reproduced by 8-bromo-guanosine 3′,5′-cyclic monophosphate and suppressed in the presence of the cGMP-dependent protein kinase inhibitor KT-5823. The action of E(2), BPA, and DES in pancreatic α-cells may explain some of the effects elicited by endocrine disruptors in the metabolism of glucose and lipid

Antidiabetic Actions of an Estrogen Receptor β Selective Agonist

The estrogen receptor β (ERβ) is emerging as an important player in the physiology of the endocrine pancreas. We evaluated the role and antidiabetic actions of the ERβ selective agonist WAY200070 as an insulinotropic molecule. We demonstrate that WAY200070 enhances glucose-stimulated insulin secretion both in mouse and human islets. In vivo experiments showed that a single administration of WAY200070 leads to an increase in plasma insulin levels with a concomitant improved response to a glucose load. Two-week treatment administration increased glucose-induced insulin release and pancreatic β-cell mass and improved glucose and insulin sensitivity. In addition, streptozotocin-nicotinamide–induced diabetic mice treated with WAY200070 exhibited a significant improvement in plasma insulin levels and glucose tolerance as well as a regeneration of pancreatic β-cell mass. Studies performed in db/db mice demonstrated that this compound restored first-phase insulin secretion and enhanced pancreatic β-cell mass. We conclude that ERβ agonists should be considered as new targets for the treatment of diabetes.This work was supported by Generalitat Valenciana grant PROMETEO/2011/080, Ministerio de Economia y Competitividad BFU2011-28358, and Ministerio de Economía y Competitividad BFU2010-21773 and BFU2008-1942; the Swedish Cancer Fund; the Emerging Technology Fund of Texas; and the Robert A. Welch Foundation (E-0004)