Endocrine disruptors in the etiology of type 2 diabetes mellitus

A Review of Current Trends with Type 2 Diabetes Epidemiology, Aetiology, Pathogenesis, Treatments and Future Perspectives

Type 2 diabetes (T2D), which has currently become a global pandemic, is a metabolic disease largely characterised by impaired insulin secretion and action. Significant progress has been made in understanding T2D aetiology and pathogenesis, which is discussed in this review. Extrapancreatic pathology is also summarised, which demonstrates the highly multifactorial nature of T2D. Glucagon-like peptide (GLP)-1 is an incretin hormone responsible for augmenting insulin secretion from pancreatic beta-cells during the postprandial period. Given that native GLP-1 has a very short half-life, GLP-1 mimetics with a much longer half-life have been developed, which are currently an effective treatment option for T2D by enhancing insulin secretion in patients. Interestingly, there is continual emerging evidence that these therapies alleviate some of the post-diagnosis complications of T2D. Additionally, these therapies have been shown to induce weight loss in patients, suggesting they could be an alternative to bariatric surgery, a procedure associated with numerous complications. Current GLP-1-based therapies all act as orthosteric agonists for the GLP-1 receptor (GLP-1R). Interestingly, it has emerged that GLP-1R also has allosteric binding sites and agonists have been developed for these sites to test their therapeutic potential. Recent studies have also demonstrated the potential of bi- and tri-agonists, which target multiple hormonal receptors including GLP-1R, to more effectively treat T2D. Improved understanding of T2D aetiology/pathogenesis, coupled with the further elucidation of both GLP-1 activity/targets and GLP-1R mechanisms of activation via different agonists, will likely provide better insight into the therapeutic potential of GLP-1-based therapies to treat T2D.

Adipose tissue cadmium concentrations as a potential risk factor for insulin resistance and future type 2 diabetes mellitus in GraMo adult cohort

Adipose tissue has been recently highlighted as a promising matrix for evaluation of cadmium's (Cd) long-term exposure although not frequently considered in epidemiological studies. The association between Cd exposure and type 2 Diabetes Mellitus (T2DM) remains unclear. This work aimed to explore the association between adipose tissue Cd levels and T2DM incidence over a 16-year follow-up in an adult cohort from Southern Spain considering smoking status. We also performed complementary cross-sectional analyses focused on subclinical markers of glucose homeostasis at recruitment. Clinical information was obtained from hospital databases. Socio-demographic characteristics, lifestyle and diet were collected by face-to-face interviews. Homeostatic model assessment (HOMA) values of insulin sensitivity/resistance and β-cell function were calculated using fasting serum glucose, insulin, and C-peptide levels at recruitment. Adipose tissue Cd concentrations were quantified by inductively coupled plasma mass spectrometry. Statistical analyses were performed by means of Cox-regression and multivariable linear regression models. Participants in the 4th quartile (Q4) of Cd concentrations showed a non statistically-significant increased T2DM risk (Hazard Ratio (HR) Q4 vs Q1: 1.97; 95% Confidence Interval (CI): 0.69, 5.66). This association was particularly strong and suggestive in current smokers (HR: 2.19; 95% CI: 0.98, 4.98). Interestingly, smokers in the 2nd tertile (T2) of adipose tissue Cd levels showed increased log-transformed insulin resistance (beta T2 vs T1: 0.52; 95% CI: 0.07, 0.97), as well as higher log-transformed insulin levels (beta T2 vs T1: 0.52; 95% CI: 0.08, 0.95). We found evidences supporting that Cd exposure, particularly from tobacco smoking, could be a risk factor for T2DM. In addition, our results support the potential relevance of adipose tissue as a matrix for Cd exposure assessment.

Endocrine disruption in Crohn's disease: Bisphenol A enhances systemic inflammatory response in patients with gut barrier translocation of dysbiotic microbiota products

The relevance of environmental triggers in Crohn's disease remains poorly explored, despite the well-known association between industrialization and disease onset/progression. We have aimed at evaluating the influence of endocrine disrupting chemicals in CD patients. We performed a prospective observational study on consecutive patients diagnosed of CD. Serum levels of endocrine disruptors, short-chain fatty acids, tryptophan and cytokines were measured. Bacterial-DNA and serum endotoxin levels were also evaluated. Gene expression of ER-α, ER-β and GPER was measured in PBMCs. All patients were genotyped for NOD2 and ATG16L1 polymorphisms. A series of 200 CD patients (140 in remission, 60 with active disease) was included in the study. Bisphenol A was significantly higher in patients with active disease versus remission and in colonic versus ileal disease. GPER was significantly increased in active patients and correlated with BPA levels. BPA was significantly increased in patients with bacterial-DNA and correlated with serum endotoxin levels, (r = 0.417; P = .003). Serum butyrate and tryptophan levels were significantly lower in patients with bacterial-DNA and an inverse relationship was present between them and BPA levels (r = -0.491; P = .001) (r = -0.611; P = .001). Serum BPA levels correlated with IL-23 (r = 0.807; P = .001) and IL-17A (r = 0.743; P = .001). The multivariate analysis revealed an independent significant contribution of BPA and bacterial-DNA to serum levels of IL-23 and IL-17A. In conclusion, bisphenol A significantly affects systemic inflammatory response in CD patients with gut barrier disruption and dysbiotic microbiota secretory products in blood. These results provide evidence of an endocrine disruptor playing an actual pathogenic role on CD.

Prediction Models for Type 2 Diabetes Risk in the General Population: A Systematic Review of Observational Studies

OBJECTIVES

This study aimed to provide an overview of prediction models of undiagnosed type 2 diabetes mellitus (U-T2DM) or the incident T2DM (I-T2DM) using the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) checklist and the prediction model risk of the bias assessment tool (PROBAST).

DATA SOURCES

Both PUBMED and EMBASE databases were searched to guarantee adequate and efficient coverage.

STUDY SELECTION

Articles published between December 2011 and October 2019 were considered.

DATA EXTRACTION

For each article, information on model development requirements, discrimination measures, calibration, overall performance, clinical usefulness, overfitting, and risk of bias (ROB) was reported.

RESULTS

The median (interquartile range; IQR) number of the 46 study populations for model development was 5711 (1971 - 27426) and 2457 (2060 - 6995) individuals for I-T2DM and U-T2DM, respectively. The most common reported predictors were age and body mass index, and only the Qrisk-2017 study included social factors (e.g., Townsend score). Univariable analysis was reported in 46% of the studies, and the variable selection procedure was not clear in 17.4% of them. Moreover, internal and external validation was reported in 43% the studies, while over 63% of them reported calibration. The median (IQR) of AUC for I-T2DM models was 0.78 (0.74 - 0.82); the corresponding value for studies derived before October 2011 was 0.80 (0.77 - 0.83). The highest discrimination index was reported for Qrisk-2017 with C-statistics of 0.89 for women and 0.87 for men. Low ROB for I-T2DM and U-T2DM was assessed at 18% and 41%, respectively.

CONCLUSIONS

Among prediction models, an intermediate to poor quality was reassessed in several aspects of model development and validation. Generally, despite its new risk factors or new methodological aspects, the newly developed model did not increase our capability in screening/predicting T2DM, mainly in the analysis part. It was due to the lack of external validation of the prediction models.

Metabolic pathways, alterations in miRNAs expression and effects of genetic polymorphisms of bisphenol a analogues: A systematic review

Bisphenol A (BPA) is one of the most common endocrine disruptors found in the environment and its harmful health effects in humans and wildlife have been extensively reported One of the main aims of this review was to examine the metabolic pathways of BPA and BPA substitutes and the endocrine disrupting properties of their metabolites. According to the available literature, phase I and phase II metabolic reactions play an important role in the detoxification process of bisphenols (BPs), but their metabolism can also lead to the formation of highly reactive metabolites. The second part of this work addresses the associations between exposure to BPA and its analogues with the alterations in miRNAs expression and the effects of single nucleotide polymorphisms (SNPs). Available scientific evidence shows that BPs can dysregulate the expression of several miRNAs, and in turn, these miRNAs could be considered as epigenetic biomarkers to prevent the development of a variety of BP-mediated diseases. Interestingly, genetic polymorphisms are able to modify the relationship of BPA exposure with the risk of adverse health effects, suggesting that interindividual genetic differences modulate the susceptibility to the effects of environmental contaminants.

Effect of lobeglitazone on motor function in rat model of Parkinson's disease with diabetes co-morbidity

Parkinson's disease (PD) and diabetes mellitus share similar pathophysiological characteristics, genetic and environmental factors. It has been reported that people with diabetes mellitus appear to have a remarkable higher incidence of PD than age matched non diabetic individuals. Evidences suggest that use of antidiabetic glitazone is associated with a diminished risk of PD incidence in patients with diabetes. This study examined the effect of lobeglitazone, a member of thiazolidinedione class, in rat model of Parkinson's disease with diabetes co-morbidity. Rats received either rotenone and/or a combination of streptozocin and a high calorie diet for disease induction and they were treated with different doses of lobeglitazone or its vehicle. Behavioral tests comprising rotarod, bar test and rearing test were conducted to evaluate the motor function. Changes in the level tyrosine hydroxylase, TNF-α and NF-κB were analyzed using ELISA. In the same brain regions the possible changes in PPAR-γ receptor level were evaluated. Findings showed that although lobeglitazone tends to reverse the effect of rotenone in animals with diabetes, it was just able to prevent partly the motor defect in rearing test. Furthermore, lobeglitazone (1 mg/kg) reversed, in substantia nigra and striatum, the changes in tyrosine hydroxylase, TNF-α, NF-κB and PPAR-γ receptor content induced by rotenone in rats with diabetic condition. Although other preclinical studies are needed, these findings suggest that lobeglitazone is a promising neuroprotective candidate for clinical trials for PD patients with diabetes co-morbidity.

The possible effects of mono butyl phthalate (MBP) and mono (2-ethylhexyl) phthalate (MEHP) on INS-1 pancreatic beta cells

Mono-2-ethyhexyl phthalate (MEHP), an environmental xenoestrogen, is widely used in the production of polyvinyl chloride materials and can be easily accumulated in human body. MBP is the active monoester metabolite of di butyl phthalate that is widely used as plasticizer in many products such as plastic toys, food packaging, personal care products, as well as an additive in lubricants, eliminating foams, and lotions. The presented in-vitro cytotoxicity study focused on time-dependent and combinatory exposure scenarios. We chose these phthalates because they are posed a considerable interest because of their contribution to insulin resistance, type-2 diabetes and obesity. All experiments performed in INS-1 pancreatic beta cells show moderate cytotoxicity with a time-dependent increase in effectiveness. INS-1 cells were treated with 0.001, 0.01, 0.1, 1, or 10-μM MEHP and MBP for 24, 48, and 72 h. Our results showed that cell viability was decreased and total oxidant levels were increased. Also, mRNA expression levels with asscociated beta cells were measured and for MBP dose groups, all mRNA expression levels were decreased. In conclusion, these findings suggest that, MEHP and MBP are have a negative and distruptor role on pancreatic beta cells and it will be linked with insulin resistance and type 2 diabetes.

In utero exposure to phenanthrene induced islet cell dysfunction in adult mice: Sex differences in the effects and potential causes

Epidemiological studies show that the burden of polycyclic aromatic hydrocarbons in human body is associated with the occurrence of insulin resistance and diabetes. In the present study, pregnant mice were exposed to phenanthrene (Phe) at doses of 0, 60 and 600 μg/kg body weight of by gavage once every 3 days. The female F1 mice at 120 days of age showed no change in their fasting glucose levels (FGLs) but exhibited significantly decreased homeostasis model assessment (HOMA) β-cell (49% and 43%) and significantly downregulated pancreatic proinsulin gene (ins2) transcription. The downregulation of transcription factors, such as PDX1, PAX4 and FGF21, indicated impaired development and function of β-cells. The significantly reduced α-cell mass in 60 and 600 μg/kg groups, and the significantly downregulated expression of proglucagon gene gcg and ARX in the 600 μg/kg group suggested that the development and function of α-cells had been impacted. The males exhibited significantly increased FGLs (1.14- and 1.15-fold) in Phe exposed treatments and significantly elevated HOMA β-cell (3.15-fold) in the 600 μg/kg group. Upregulated ins2 transcription and FGF21 protein in male mice prenatally exposed to 600 μg/kg Phe suggested that these animals appeared compensatory enhancement in β-cell function. The reduced serum estradiol levels and downregulated pancreatic estrogen receptor α and β were responsible for the dysfunction of β-cells in the females. In the males, the significantly elevated androgen levels in the 600 μg/kg group might be related to the upregulated ins2 transcription, and the increased expression of pancreatic FGF21 further demonstrated the enhancement of β-cell potential. The results will be helpful for assessing the risk of developing diabetes in adulthood after prenatal exposure to phenanthrene.

Long-term exposure to low doses of bisphenol S has hypoglycaemic effect in adult male mice by promoting insulin sensitivity and repressing gluconeogenesis

Bisphenol S (BPS), an industrial chemical that is a structural analogue of bisphenol A, has been widely reported to be involved in various biological processes. Epidemiological studies have demonstrated that exposure to BPS is associated with dysglycaemia-related health outcomes. The role of BPS in glucose metabolism, however, remains controversial. In this study, we aimed to investigate the effects of chronic exposure to environmentally relevant concentrations of BPS on glucose metabolism in different nutritionally conditioned mice. Our results revealed that 1-month exposure to a BPS dosage of 100 μg/kg bw slightly increased the insulin sensitivity of normal diet-fed mice, and that this effect was enhanced after 3-month exposure. It was also found that BPS exposure attenuated insulin resistance and reduced gluconeogenesis in high-fat diet-fed mice. Consequently, the concentrations of hepatic metabolites related to glucose metabolism were altered in both groups of mice. Moreover, thyroid hormone signalling was disrupted after BPS administration in both groups of mice. Taken together, our results demonstrated that chronic exposure to environmentally relevant concentrations of BPS exerted an unexpected hypoglycaemic effect in mice of different nutritional statuses, and that this was partly attributable to disrupted thyroid hormone signalling.

Oleuropein attenuates the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-perturbing effects on pancreatic β-cells

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an endocrine disrupting compound and persistent organic pollutant that has been associated with diabetes in several epidemiological studies. Oleuropein, a major phenolic compound in olive fruit, is a superior antioxidant and radical scavenger. This study aimed to examine the effects of oleuropein against TCDD-induced stress response in a pancreatic beta cell line, INS-1 cells. Cells were pre-incubated with various concentrations of oleuropein and then stimulated with TCDD (10 nM) for 48 hrs. When treated with TCDD, INS-1 cells produced robust amounts of prostaglandin E₂ (PGE₂) compared to the untreated control, and this increase was inhibited by oleuropein treatment. TCDD increased Ca²⁺-independent phospholipase A₂ (iPLA₂β) level, but had no effect on Group 10 secretory phospholipase A₂ (PLA₂G10) level, while oleuropein deceased the levels of iPLA₂β and PLA₂G10 in the presence of TCDD. Cyclooxygenase-1 (COX-1) was significantly increased by TCDD treatment and attenuated with oleuropein pretreatment. Oleuropein decreased TCDD-mediated production of JNK, TNF-α, and ROS. In addition, oleuropein increased Akt and GLUT2 levels suppressed by TCDD in INS-1 cells. Thus, the results suggest that oleuropein prevents pancreatic beta cell impairment by TCDD.

Early Life Exposure to Food Contaminants and Social Stress as Risk Factor for Metabolic Disorders Occurrence?-An Overview

The global prevalence of obesity has been increasing in recent years and is now the major public health challenge worldwide. While the risks of developing metabolic disorders (MD) including obesity and type 2 diabetes (T2D) have been historically thought to be essentially driven by increased caloric intake and lack of exercise, this is insufficient to account for the observed changes in disease trends. Based on human epidemiological and pre-clinical experimental studies, this overview questioned the role of non-nutritional components as contributors to the epidemic of MD with a special emphasis on food contaminants and social stress. This overview examines the impact of early life adverse events (ELAE) focusing on exposures to food contaminants or social stress on weight gain and T2D occurrence in the offspring and explores potential mechanisms leading to MD in adulthood. Indeed, summing up data on both ELAE models in parallel allowed us to identify common patterns that appear worthwhile to study in MD etiology. This overview provides some evidence of a link between ELAE-induced intestinal barrier disruption, inflammation, epigenetic modifications, and the occurrence of MD. This overview sums up evidence that MD could have developmental origins and that ELAE are risk factors for MD at adulthood independently of nutritional status.

Ventricular Fibrosis and Coronary Remodeling Following Short-Term Exposure of Healthy and Malnourished Mice to Bisphenol A

Bisphenol-A (BPA) is an endocrine disruptor associated with higher risk of insulin resistance, type 2 diabetes, and cardiovascular diseases especially in susceptible populations. Because malnutrition is a nutritional disorder associated with high cardiovascular risk, we sought to compare the effects of short-term BPA exposure on cardiovascular parameters of healthy and protein-malnourished mice. Postweaned male mice were fed a normo- (control) or low-protein (LP) diet for 8 weeks and then exposed or not to BPA (50 μg kg⁻¹ day⁻¹) for the last 9 days. Systolic blood pressure was higher in BPA or LP groups compared with the control group. However, diastolic blood pressure was enhanced by BPA only in malnourished mice. Left ventricle (LV) end diastolic pressure (EDP), collagen deposition, and CTGF mRNA expression were higher in the control or malnourished mice exposed to BPA than in the respective nonexposed groups. Nevertheless, mice fed LP diet exposed to BPA exhibited higher angiotensinogen and cardiac TGF-β1 mRNA expression than mice treated with LP or BPA alone. Wall:lumen ratio and cross-sectional area of intramyocardial arteries were higher either in the LP or BPA group compared with the control mice. Taken together, our data suggest that short-term BPA exposure results in LV diastolic dysfunction and fibrosis, and intramyocardial arteries inward remodeling, besides potentiate protein malnutrition-induced hypertension and cardiovascular risk.

Epigenetic Modifications Associated with Exposure to Endocrine Disrupting Chemicals in Patients with Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) remains a significant clinical and public health issue due to its increasing prevalence and the possibility for numerous short- and long-term complications. The growing incidence of GDM seems to coincide with the widespread use of endocrine disrupting chemicals (EDCs). The extensive production and common use of these substances in everyday life has resulted in constant exposure to harmful substances from the environment. That may result in epigenetic changes, which may manifest themselves also after many years and be passed on to future generations. It is important to consider the possible link between environmental exposure to endocrine disrupting chemicals (EDCs) during pregnancy, epigenetic mechanisms and an increased risk for developing gestational diabetes mellitus (GDM). This manuscript attempts to summarize data on epigenetic changes in pregnant women suffering from gestational diabetes in association with EDCs. There is a chance that epigenetic marks may serve as a tool for diagnostic, prognostic, and therapeutic measures.

Endocrine-Disrupting Chemicals and Infectious Diseases: From Endocrine Disruption to Immunosuppression

Endocrine-disrupting chemicals (EDCs) are hormonally active compounds in the environment that interfere with the body's endocrine system and consequently produce adverse health effects. Despite persistent public health concerns, EDCs remain important components of common consumer products, thus representing ubiquitous contaminants to humans. While scientific evidence confirmed their contribution to the severity of Influenza A virus (H1N1) in the animal model, their roles in susceptibility and clinical outcome of the coronavirus disease (COVID-19) cannot be underestimated. Since its emergence in late 2019, clinical reports on COVID-19 have confirmed that severe disease and death occur in persons aged ≥65 years and those with underlying comorbidities. Major comorbidities of COVID-19 include diabetes, obesity, cardiovascular disease, hypertension, cancer, and kidney and liver diseases. Meanwhile, long-term exposure to EDCs contributes significantly to the onset and progression of these comorbid diseases. Besides, EDCs play vital roles in the disruption of the body's immune system. Here, we review the recent literature on the roles of EDCs in comorbidities contributing to COVID-19 mortality, impacts of EDCs on the immune system, and recent articles linking EDCs to COVID-19 risks. We also recommend methodologies that could be adopted to comprehensively study the role of EDCs in COVID-19 risk.

Update on the Health Effects of Bisphenol A: Overwhelming Evidence of Harm

In 1997, the first in vivo bisphenol A (BPA) study by endocrinologists reported that feeding BPA to pregnant mice induced adverse reproductive effects in male offspring at the low dose of 2 µg/kg/day. Since then, thousands of studies have reported adverse effects in animals administered low doses of BPA. Despite more than 100 epidemiological studies suggesting associations between BPA and disease/dysfunction also reported in animal studies, regulatory agencies continue to assert that BPA exposures are safe. To address this disagreement, the CLARITY-BPA study was designed to evaluate traditional endpoints of toxicity and modern hypothesis-driven, disease-relevant outcomes in the same set of animals. A wide range of adverse effects was reported in both the toxicity and the mechanistic endpoints at the lowest dose tested (2.5 µg/kg/day), leading independent experts to call for the lowest observed adverse effect level (LOAEL) to be dropped 20 000-fold from the current outdated LOAEL of 50 000 µg/kg/day. Despite criticism by members of the Endocrine Society that the Food and Drug Administration (FDA)'s assumptions violate basic principles of endocrinology, the FDA rejected all low-dose data as not biologically plausible. Their decisions rely on 4 incorrect assumptions: dose responses must be monotonic, there exists a threshold below which there are no effects, both sexes must respond similarly, and only toxicological guideline studies are valid. This review details more than 20 years of BPA studies and addresses the divide that exists between regulatory approaches and endocrine science. Ultimately, CLARITY-BPA has shed light on why traditional methods of evaluating toxicity are insufficient to evaluate endocrine disrupting chemicals.

Is Technical-Grade Chlordane an Obesogen?

The prevalence of obesity has tripled in recent decades and is now considered an alarming public health problem. In recent years, a group of endocrine disruptors, known as obesogens, have been directly linked to the obesity epidemic. Its etiology is generally associated with a sedentary lifestyle, a high-fat diet and genetic predisposition, but environmental factors, such as obesogens, have also been reported as contributors for this pathology. In brief, obesogens are exogenous chemical compounds that alter metabolic processes and/or energy balance and appetite, thus predisposing to weight gain. Although this theory is still recent, the number of compounds with suspected obesogenic activity has steadily increased over the years, though many of them remain a matter of debate. Technical-grade chlordane is an organochlorine pesticide widely present in the environment, albeit at low concentrations. Highly lipophilic compounds can be metabolized by humans and animals into more toxic and stable compounds that are stored in fat tissue and consequently pose a danger to the human body, including the physiology of adipose tissue, which plays an important role in weight regulation. In addition, technical-grade chlordane is classified as a persistent organic pollutant, a group of chemicals whose epidemiological studies are associated with metabolic disorders, including obesity. Herein, we discuss the emerging roles of obesogens as threats to public health. We particularly discuss the relevance of chlordane persistence in the environment and how its effects on human and animal health provide evidence for its role as an endocrine disruptor with possible obesogenic activity.

Bisphenol-S and Bisphenol-F alter mouse pancreatic β-cell ion channel expression and activity and insulin release through an estrogen receptor ERβ mediated pathway

Bisphenol-S (BPS) and Bisphenol-F (BPF) are current Bisphenol-A (BPA) substitutes. Here we used pancreatic β-cells from wild type (WT) and estrogen receptor β (ERβ) knockout (BERKO) mice to investigate the effects of BPS and BPF on insulin secretion, and the expression and activity of ion channels involved in β-cell function. BPS or BPF rapidly increased insulin release and diminished ATP-sensitive K⁺ (K_ATP) channel activity. Similarly, 48 h treatment with BPS or BPF enhanced insulin release and decreased the expression of several ion channel subunits in β-cells from WT mice, yet no effects were observed in cells from BERKO mice. PaPE-1, a ligand designed to preferentially trigger extranuclear-initiated ER pathways, mimicked the effects of bisphenols, suggesting the involvement of extranuclear-initiated ERβ pathways. Molecular dynamics simulations indicated differences in ERβ ligand-binding domain dimer stabilization and solvation free energy among different bisphenols and PaPE-1. Our data suggest a mode of action involving ERβ whose activation alters three key cellular events in β-cell, namely ion channel expression and activity, and insulin release. These results may help to improve the hazard identification of bisphenols.

Exposure to persistent organic pollutants and the risk of type 2 diabetes: a case-cohort study

AIMS

To explore exposure to 22 persistent organic pollutants (POPs) and incident type 2 diabetes in a population-based, prospective cohort.

METHODS

This case-cohort study on 753 participants without type 2 diabetes at baseline, was followed-up over nine years, as part of the French D.E.S.I.R. cohort. We measured 22 POPs in fasting serum at baseline. The associations between baseline POP concentrations, pre-adjusted for lipids, BMI, age and sex, with incident type 2 diabetes, were assessed using Prentice-weighted Cox regression models (time scale: age), adjusted for traditional confounding factors. POPs were also modelled summed in functional groups: polychlorinated biphenyls (∑PCB) and organochlorines (∑OC) and also individually, after log-transformation, in adjusted Cox models.

RESULTS

There were 200 incident diabetes cases over nine years. Pre-adjusted POP concentrations were not related to diabetes risk for any of the 22 POPs examined. The fully-adjusted hazard ratios (HRs) per interquartile range of the pre-adjusted POPs, ranged from 0.87 (95% CI: 0.64,1.19) to 1.22 (0.93,1.59,). For dichlorodiphenyldichloroethylene (p, p'-DDE) and dichlorodiphenyltrichloroethane (p, p'-DDT), the HRs were 1.09 (0.83,1.43) and 0.89 (0.70,1.13), respectively. The HRs for PeCB, HCB, β-HCH, γ-HCH, oxychlordane, trans-nonachlor were 0.98 (0.85,1.13), 1.06 (0.84,1.33), 1.22 (0.93,1.59), 1.13 (0.89,1.42), 1.00 (0.76,1.31), 0.86 (0.66,1.13), respectively. HRs for ∑PCB, ∑OC and for individual log-transformed POPs did not differ significantly from one.

CONCLUSION

We did not observe any relations between exposure to POPs and diabetes in this population-based cohort. These results do not support causal inferences reported in previous studies linking serum POP concentrations and diabetes risk.

Bisphenol A and Type 2 Diabetes Mellitus: A Review of Epidemiologic, Functional, and Early Life Factors

Type 2 diabetes mellitus (T2DM) is characterised by insulin resistance and eventual pancreatic β-cell dysfunction, resulting in persistent high blood glucose levels. Endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA) are currently under scrutiny as they are implicated in the development of metabolic diseases, including T2DM. BPA is a pervasive EDC, being the main constituent of polycarbonate plastics. It can enter the human body by ingestion, through the skin, and cross from mother to offspring via the placenta or breast milk. BPA is a xenoestrogen that alters various aspects of beta cell metabolism via the modulation of oestrogen receptor signalling. In vivo and in vitro models reveal that varying concentrations of BPA disrupt glucose homeostasis and pancreatic β-cell function by altering gene expression and mitochondrial morphology. BPA also plays a role in the development of insulin resistance and has been linked to long-term adverse metabolic effects following foetal and perinatal exposure. Several epidemiological studies reveal a significant association between BPA and the development of insulin resistance and impaired glucose homeostasis, although conflicting findings driven by multiple confounding factors have been reported. In this review, the main findings of epidemiological and functional studies are summarised and compared, and their respective strengths and limitations are discussed. Further research is essential for understanding the exact mechanism of BPA action in various tissues and the extent of its effects on humans at environmentally relevant doses.

Association between occupations and selected noncommunicable diseases: A matched case-control among Thai informal workers

OBJECTIVES

We conducted a matched case-control study of informal workers to determine the association between occupational classification and selected types of noncommunicable diseases (NCDs).

METHOD

We extracted data of patients aged ≥18 years from the Thai National Health Security Office database (NHSO) during 2011-2014. Cases were patients who had a primary diagnosis of: diabetes mellitus (E10-E14), hypertension (I10-I15), ischemic heart disease (I20-I25) or stroke (I60-69), or thyroid gland disorder (E00-E07). Controls were patients who had a primary diagnosis of intestinal or parasitic infections (A00-A09 and B25-B99), and were randomly matched 1:1 with cases of the same age and residential area. The four-digit occupation codes recorded in the NHSO were grouped and recoded based on the submajor groups of International Standard Classification of Occupations (ISCO-08) as follows: agricultural workers, unskilled workers, service, and sales workers. Analysis was performed using multivariable conditional logistic regression.

RESULTS

Occupation and sex inequalities were present among all the selected NCDs. Higher risk for the four selected NCDs was found among unskilled workers. Stronger risk for cardiovascular disease was present among males, while females had a higher risk for metabolic disorders.

CONCLUSIONS

There is a need to understand what are the key factors that increase the risk for NCDs among informal sector workers. Health promotion campaigns are needed to raise awareness among economically and social disadvantaged informal workers about the risk for NCDs. This will require collaboration between public health and the workforce, and allocation of government budgets to address the needs of these workers.

Exposure to pollutants altered glucocorticoid signaling and clock gene expression in female mice. Evidence of tissue- and sex-specificity

Environmental pollutants suspected of disrupting the endocrine system are considered etiologic factors in the epidemic of metabolic disorders. As regulation of energy metabolism relies on the integrated action of a large number of hormones, we hypothesized that certain chemicals could trigger changes in glucocorticoid signaling. To this end, we exposed C57Bl6/J female and male mice between 5 and 20 weeks of age to a mixture of 2,3,7,8- tetrachlorodibenzo-p-dioxin (20 pg/kg body weight/day [bw/d]), polychlorobiphenyl 153 (200 ng/kg bw/d), di-[2-ethylhexyl]-phthalate (500 μg/kg bw/d) and bisphenol A (40 μg/kg bw/d). In female mice fed a standard diet (ST), we observed a decrease in plasma levels of leptin as well as a reduced expression of corticoid receptors Nr3c1 and Nr3c2, of leptin and of various canonical genes related to the circadian clock machinery in visceral (VAT) but not subcutaneous (SAT) adipose tissue. However, Nr3c1 and Nr3c2 mRNA levels did not change in high-fat-fed females exposed to pollutants. In ST-fed males, pollutants caused the same decrease of Nr3c1 mRNA levels in VAT observed in ST-fed females but levels of Nr3c2 and other clock-related genes found to be down-regulated in female VAT were enhanced in male SAT and not affected in male VAT. The expression of corticoid receptors was not affected in the livers of both sexes in response to pollutants. In summary, exposure to a mixture of pollutants at doses lower than the no-observed adverse effect levels (NoAELs) resulted in sex-dependent glucocorticoid signaling disturbances and clock-related gene expression modifications in the adipose tissue of ST-fed mice.

Identifying features of a mobile-based application for self-care of people living with T2DM

INTRODUCTION

Diabetes self-care requires support to empower patients to improve self-monitoring and maintain the necessary self-care behaviors. We aimed to identify features of a mobile-based application as a technology-based device for self-care of people living with T2DM.

METHOD

This study was conducted in two main phases in 2020. In the first phase, a literature review study was performed to identify the data elements and technical features of the T2DM self-care application. In the second phase, using the information obtained from the review of similar articles, a questionnaire was designed to validate identified requirements. The statistical population of the present study consisted of 22 endocrinologists and metabolic specialists.

RESULTS

Identification of 55 data elements and technical features for mobile-based self-care application for people with T2DM, and according to the statistical population, 15data elements for demographic requirements, 16 data elements for clinical requirements, and 17 features for the technical capability of this app were selected.

CONCLUSION

Blood sugar monitoring, exercise, nutrition, weight monitoring, and educational capabilities were the most highlighted technical features of the T2DM self-care application. Software designers can use these requirements to design a self-care app for people with type-2 diabetes that can help manage and improve patients' health status.

Endocrine Disruptors and the Induction of Insulin Resistance

INTRODUCTION

The incidence of insulin resistance syndrome and type 2 diabetes mellitus has increased at an alarming rate worldwide and constitutes a serious challenge to public health care in the 21st century. Endocrine disrupting chemicals are defined as "substances or mixtures of substances that alter the endocrine system functions and, hence, adversely affect organisms, their progeny, or sub populations" and may be associated with this increase in prevalence.

OBJECTIVE

This study aimed to assess the role of endocrine disrupting chemicals in insulin resistance and the importance of approaching the subject during anamnesis.

METHODS

A full review of the literature regarding insulin resistance, type-2 diabetes and endocrine disruptors were conducted.

CONCLUSION

Large-scale production and distribution of endocrine disrupting chemicals coincide with the increase in the prevalence of insulin resistance globally. In recent years, studies have shown that endocrine disrupting chemicals are positively associated with insulin resistance syndrome, evidenced by worse prognoses among individuals with higher levels of exposure. Health professionals should recognize the forms of exposure, most susceptible people, and lifestyle habits that can worsen patients' prognoses.

Oxidative Stress in NAFLD: Role of Nutrients and Food Contaminants

Non-alcoholic fatty liver disease (NAFLD) is often the hepatic expression of metabolic syndrome and its comorbidities that comprise, among others, obesity and insulin-resistance. NAFLD involves a large spectrum of clinical conditions. These range from steatosis, a benign liver disorder characterized by the accumulation of fat in hepatocytes, to non-alcoholic steatohepatitis (NASH), which is characterized by inflammation, hepatocyte damage, and liver fibrosis. NASH can further progress to cirrhosis and hepatocellular carcinoma. The etiology of NAFLD involves both genetic and environmental factors, including an unhealthy lifestyle. Of note, unhealthy eating is clearly associated with NAFLD development and progression to NASH. Both macronutrients (sugars, lipids, proteins) and micronutrients (vitamins, phytoingredients, antioxidants) affect NAFLD pathogenesis. Furthermore, some evidence indicates disruption of metabolic homeostasis by food contaminants, some of which are risk factor candidates in NAFLD. At the molecular level, several models have been proposed for the pathogenesis of NAFLD. Most importantly, oxidative stress and mitochondrial damage have been reported to be causative in NAFLD initiation and progression. The aim of this review is to provide an overview of the contribution of nutrients and food contaminants, especially pesticides, to oxidative stress and how they may influence NAFLD pathogenesis.

Adipose Tissue and Endocrine-Disrupting Chemicals: Does Sex Matter?

Obesity and metabolic-related diseases, among which diabetes, are prominent public health challenges of the 21st century. It is now well acknowledged that pollutants are a part of the equation, especially endocrine-disrupting chemicals (EDCs) that interfere with the hormonal aspect. The aim of the review is to focus on adipose tissue, a central regulator of energy balance and metabolic homeostasis, and to highlight the significant differences in the endocrine and metabolic aspects of adipose tissue between males and females which likely underlie the differences of the response to exposure to EDCs between the sexes. Moreover, the study also presents an overview of several mechanisms of action by which pollutants could cause adipose tissue dysfunction. Indeed, a better understanding of the mechanism by which environmental chemicals target adipose tissue and cause metabolic disturbances, and how these mechanisms interact and sex specificities are essential for developing mitigating and sex-specific strategies against metabolic diseases of chemical origin. In particular, considering that a scenario without pollutant exposure is not a realistic option in our current societies, attenuating the deleterious effects of exposure to pollutants by acting on the gut-adipose tissue axis may constitute a new direction of research.

Pre- and post-diagnostic blood profiles of perfluoroalkyl acids in type 2 diabetes mellitus cases and controls

BACKGROUND

Studies exploring the associations between perfluoroalkyl acids (PFAAs) and type 2 diabetes mellitus (T2DM) are rather limited and have reported conflicting results. All studies to date, including prospective ones, have relied on a single blood sample to study this association. Similarly, studies investigating how T2DM status may influence the longitudinal changes in PFAA concentrations have not been previously performed. As PFAA concentrations in humans have changed considerably over the last two decades, and as individuals diagnosed with T2DM usually undergo lifestyle changes that could influence these concentrations, a single blood sample may not necessarily reflect the life-time exposure to PFAA concentrations. Hence, repeated measurements from the same individuals will extend our understanding of how PFAAs are associated with T2DM. The present study, therefore, aimed to explore associations between pre- and post-diagnostic PFAA blood profiles and T2DM and assess factors associated with longitudinal changes in PFAAs in T2DM cases and controls.

METHODS

Questionnaire data and blood samples from women participating in the Norwegian Women and Cancer study were used to conduct a nested case-control study among 46 T2DM cases matched to 85 non-diabetic controls. PFAAs were measured in blood samples collected prior to (2001/02) and after (2005/6) T2DM diagnosis. We investigated the association between PFAAs and incident and prevalent T2DM using conditional logistic regression. We assessed the longitudinal changes in PFAA concentrations within and between matched cases and controls using t-tests and linear regression models.

RESULTS

We observed no significant associations between pre-diagnostic PFAA concentrations and T2DM incidence. Similar results were observed for the post-diagnostic PFAA concentrations and T2DM prevalence. Decrease over time in PFAA concentrations were observed for PFOA and ∑PFOS concentrations, whereas increase over time were observed for PFNA, PFDA and PFUnDA concentrations. Longitudinal trends in PFAA concentrations among T2DM cases were similar to the changes observed in controls.

CONCLUSIONS

The study did not find evidence of association between PFAAs and incident or prevalent T2DM. The longitudinal changes in PFAAs concentrations were not influenced by T2DM status.

Biomarkers of metabolic disorders and neurobehavioral diseases in a PCB- exposed population: What we learned and the implications for future research

Polychlorinated biphenyls (PCBs) are one of the original twelve classes of toxic chemicals covered by the Stockholm Convention on Persistent Organic Pollutants (POP), an international environmental treaty signed in 2001. PCBs are present in the environment as mixtures of multiple isomers at different degree of chlorination. These compounds are manmade and possess useful industrial properties including extreme longevity under harsh conditions, heat absorbance, and the ability to form an oily liquid at room temperature that is useful for electrical utilities and in other industrial applications. They have been widely used for a wide range of industrial purposes over the decades. Despite a ban in production in 1979 in the US and many other countries, they remain persistent and ubiquitous in environment as contaminants due to their improper disposal. Humans, independent of where they live, are therefore exposed to PCBs, which are routinely found in random surveys of human and animal tissues. The prolonged exposures to PCBs have been associated with the development of different diseases and disorders, and they are classified as endocrine disruptors. Due to its ability to interact with thyroid hormone, metabolism and function, they are thought to be implicated in the global rise of obesity diabetes, and their potential toxicity for neurodevelopment and disorders, an example of gene by environmental interaction (GxE). The current review is primarily intended to summarize the evidence for the association of PCB exposures with increased risks for metabolic dysfunctions and neurobehavioral disorders. In particular, we present evidence of gene expression alterations in PCB-exposed populations to construct the underlying pathways that may lead to those diseases and disorders in course of life. We conclude the review with future perspectives on biomarker-based research to identify susceptible individuals and populations.

Low-dose Bisphenol-A Promotes Epigenetic Changes at Pparγ Promoter in Adipose Precursor Cells

Exposure to endocrine-disrupting chemicals such as Bisphenol-A (BPA) is associated with an increase in obesity prevalence. Diet is the primary cause of human exposure to this contaminant. BPA promotes obesity by inducing adipocyte dysfunction and altering adipogenesis. Contradictory evidence and unanswered questions are reported in the literature concerning the BPA effects on adipogenesis. To clarify this issue, we tested the effects of prolonged low-dose BPA exposure on different phases of adipogenesis in committed 3T3L1 and uncommitted NIH3T3 preadipocytes. Our findings show that BPA effects on the adipogenesis are mediated by epigenetic mechanisms by reducing peroxisome proliferator-activated receptor gamma (Pparγ) promoter methylation in preadipocytes. Nevertheless, in BPA-exposed 3T3L1, Pparγ expression only transiently increases as lipid accumulation at day 4 of differentiation, without altering the adipogenic potential of the precursor cells. In the absence of differentiation mix, BPA does not make the 3T3L1 an in vitro model of spontaneous adipogenesis and the effects on the Pparγ expression are still limited at day 4 of differentiation. Furthermore, BPA exposure does not commit the NIH3T3 to the adipocyte lineage, although Pparγ overexpression is more evident both in preadipocytes and during the adipocyte differentiation. Interestingly, termination of the BPA exposure restores the Pparγ promoter methylation and inflammatory profile of the 3T3L1 cells. This study shows that BPA induces epigenetic changes in a key adipogenic gene. These modifications are reversible and do not affect preadipocyte commitment and/or differentiation. We identify an alternative transcriptional mechanism by which BPA affects gene expression and demonstrate how the challenge of preventing exposure is fundamental for human health.

Influence of KRAS mutations, persistent organic pollutants, and trace elements on survival from pancreatic ductal adenocarcinoma

INTRODUCTION

Reasons why pancreatic ductal adenocarcinoma (PDAC) continues to have poor survival are only partly known. No previous studies have analyzed the combined influence of KRAS mutations, persistent organic pollutants (POPs), and trace elements upon survival in PDAC or in any other human cancer.

OBJECTIVE

To analyze the individual and combined influence of KRAS mutations, POPs, and trace elements upon survival from PDAC.

METHODS

Incident cases of PDAC (n = 185) were prospectively identified in five hospitals in Eastern Spain in 1992-1995 and interviewed face-to-face during hospital admission. KRAS mutational status was determined from tumour tissue through polymerase chain reaction and artificial restriction fragment length polymorphism. Blood and toenail samples were obtained before treatment. Serum concentrations of POPs were analyzed by high-resolution gas chromatography with electron-capture detection. Concentrations of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. Multivariable Cox proportional hazards regression was used to assess prognostic associations.

RESULTS

Patients with a KRAS mutated tumor had a 70% higher risk of early death than patients with a KRAS wild-type PDAC (hazard ratio [HR] = 1.7, p = 0.026), adjusting for age, sex, and tumor stage. KRAS mutational status was only modestly and not statistically significantly associated with survival when further adjusting by treatment or by treatment intention. The beneficial effects of treatment remained unaltered when KRAS mutational status was taken into account, and treatment did not appear to be less effective in the subgroup of patients with a KRAS mutated tumor. POPs did not materially influence survival: the adjusted HR of the highest POP tertiles was near unity for all POPs. When considering the joint effect on survival of POPs and KRAS, patients with KRAS mutated tumors had modest and nonsignificant HRs (most HRs around 1.3 to 1.4). Higher concentrations of lead, cadmium, arsenic, vanadium, and aluminium were associated with better survival. When KRAS status, POPs, and trace elements were simultaneously considered along with treatment, only the latter was statistically significantly related to survival.

CONCLUSIONS

In this study based on molecular, clinical, and environmental epidemiology, KRAS mutational status, POPs, and trace elements were not adversely related to PDAC survival when treatment was simultaneously considered; only treatment was independently related to survival. The lack of adverse prognostic effects of POPs and metals measured at the time of diagnosis provide scientific and clinical reassurance on the effects of such exposures upon survival of patients with PDAC. The weak association with KRAS mutations contributes to the scant knowledge on the clinical implications of a genetic alteration highly frequent in PDAC.

Prenatal diethylstilbestrol exposure and risk of diabetes, gallbladder disease, and pancreatic disorders and malignancies

Prenatal diethylstilbestrol (DES) exposure is associated with increased risk of hormonally mediated cancers and other medical conditions. We evaluated the association between DES and risk of pancreatic cancer and pancreatic disorders, type 2 diabetes, and gallbladder disease, which may be involved with this malignancy. Our analyses used follow-up data from the US National Cancer Institute DES Combined Cohort Study. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for age, sex, cohort, body mass index, smoking, and alcohol for the association between prenatal DES exposure and type 2 diabetes, gallbladder disease (mainly cholelithiasis), pancreatic disorders (mainly pancreatitis), and pancreatic cancer among 5667 exposed and 3315 unexposed individuals followed from 1990 to 2017. Standardized incidence rate (SIR) ratios for pancreatic cancer were based on age-, race-, and calendar year-specific general population cancer incidence rates. In women and men combined, the hazards for total pancreatic disorders and pancreatitis were greater in the prenatally DES exposed than the unexposed (HR = 11, 95% CI 2.6–51 and HR = 7.0, 95% CI 1.5–33, respectively). DES was not associated overall with gallbladder disease (HR = 1.2, 95% CI 0.88–1.5) or diabetes (HR = 1.1, 95% CI 0.9–1.2). In women, but not in men, DES exposure was associated with increased risk of pancreatic cancer compared with the unexposed (HR: 4.1, 95% CI 0.84–20) or general population (SIR: 1.9, 95% CI 1.0–3.2). Prenatal DES exposure may increase the risk of pancreatic disorders, including pancreatitis in women and men. The data suggested elevated pancreatic cancer risk in DES-exposed women, but not in exposed men.

Gene-Environmental Interplay in Bisphenol A Subchronic Animal Exposure: New Insights into the Epigenetic Regulation of Pancreatic Islets

Endocrine-disrupting chemicals (EDCs) such as bisphenol A (BPA), which is widely used in the plastic industry, have recently been considered to be involved in the pathogenesis of metabolic disorders, including obesity and diabetes. The present study aimed to examine the potentially detrimental effects of BPA on glucose and energy metabolism at the epigenetic level. The blood glucose profile of Wistar rats receiving different oral doses of BPA over 28 days was assessed. At the end of the treatment, the islets of Langerhans were isolated and purified, and their RNA content was extracted. MicroRNA (miRNA) profiling was evaluated using the next generation sequencing (NGS) method. After performing bioinformatic analysis of the NGS data, the gene ontology and data enrichment in terms of significantly disturbed miRNAs were evaluated through different databases, including Enrichr and DIANA tools. Additionally, the DNA methylation and the level of expression of two critical genes in glucose metabolism (PPARγ, Pdx1) were assessed. Subchronic BPA exposure (406 mg/kg/day) disturbed the blood glucose profile (fasting blood glucose and oral glucose tolerance) of Wistar rats and resulted in considerable cytotoxicity. NGS data analyses revealed that the expression of some crucial miRNAs involved in β-cell metabolism and diabetes occurrence and development, including miR-375, miR-676, miR-126-a, and miR-340-5p, was significantly disrupted. According to the DNA methylation evaluation, both PPARγ and Pdx1 genes underwent changes in the methylation level at particular loci on the gene's promoter. The expression levels of these genes were upregulated and downregulated, respectively. Overall, subchronic BPA exposure could cause epigenetic dysregulation at the gene level and interfere with the expression of key miRNAs and the methylation process of genes involved in glucose homeostasis. Understanding the exact underlying mechanisms by which BPA and other EDCs induce endocrine disturbance could be of great importance in the way of finding new preventive and therapeutic approaches.

High-Performance Voltammetric Aptasensing Platform for Ultrasensitive Detection of Bisphenol A as an Environmental Pollutant

Bisphenol A (BPA) as a pervasive endocrine-disrupting compound (EDC) has been shown to cause multiple detrimental effects including cardiovascular disorders, pregnancy complications, obesity, glucose metabolism disorders, and reproductive toxicity even at a concentration as low as tolerable daily intake (TDI) (4 μg/kg/day). In the present study, a novel ultra-sensitive, electrochemical aptasensor was designed using a screen-printed carbon electrode (SPCE) modified by gold nanoparticles (Au NPs) conjugated to thiolated aptamers for accurate determination of BPA in biological, industrial and environmental samples. To characterize the electrochemical properties of the aptasensor, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented. Detection of BPA was also performed through differential pulse voltammetry (DPV) in [Fe(CN)₆]^3–/4– electrolyte solution. Under optimum condition, the present electrochemical aptasensor demonstrated an outstanding linear response in the concentration range of 1 pM to 10 nM with a remarkably low limit of detection of 0.113 pM. Due to the superb affinity between anti-BPA aptamers and BPA molecules, the designed aptasensor did not show any significant interaction with other analytes in real samples. Also, fabricated biosensor remained perfectly stable in long-term storage. The analytical results of the fabricated aptasensor are well compatible with those obtained by the ELISA method, indicating the trustworthiness and reasonable accuracy of the application of aptasensor in real samples. Overall, the proposed aptasensor would be a credible and economical method of precise, reproducible, and highly selective detection of minimum levels of BPA in food containers and clinical samples. This would be a promising strategy to enhance the safety of food products and reduce the risk of BPA daily exposure.

Bisphenol-A exposure during pregnancy alters pancreatic β-cell division and mass in male mice offspring: A role for ERβ

Bisphenol-A (BPA) is a widespread endocrine disrupting chemical that constitutes a risk factor for type 2 diabetes mellitus (T2DM). Data from animal and human studies have demonstrated that early exposure to BPA results in adverse metabolic outcomes in adult life. In the present work, we exposed pregnant heterozygous estrogen receptor β (ERβ) knock out (BERKO) mice to 10 μg/kg/day BPA, during days 9-16 of pregnancy, and measured β-cell mass and proliferation in wildtype (WT) and BERKO male offspring at postnatal day 30. We observed increased pancreatic β-cell proliferation and mass in WT, yet no effect was produced in BERKO mice. Dispersed islet cells in primary culture treated with 1 nM BPA showed an enhanced pancreatic β-cell replication rate, which was blunted in pancreatic β-cells from BERKO mice and mimicked by the selective ERβ agonist WAY200070. This increased β-cell proliferation was found in male adult as well as in neonate pancreatic β-cells, suggesting that BPA directly impacts β-cell division at earliest stages of life. These findings strongly indicate that BPA during pregnancy upregulates pancreatic β-cell division and mass in an ERβ-dependent manner. Thus, other natural or artificial chemicals may use this ERβ-mediated pathway to promote similar effects.

Chronic exposure of bisphenol A impairs carbohydrate and lipid metabolism by altering corresponding enzymatic and metabolic pathways

Bisphenol-A (BPA), a widespread endocrine-disrupting chemical, has been recognized as a risk factor for metabolic disorders. BPA is considered to be involved in the impairment of carbohydrate and lipid metabolism but the underlying mechanisms still need to be elucidated. Present study was aimed to investigate the impact of BPA exposure on enzymatic and metabolic pathways that are responsible to regulate the carbohydrate and lipid metabolism. Experimental rats were exposed to different doses of BPA (50, 500, 2500 and 5000 μg/kg/day orally) dissolved in 1.5% dimethyl sulfoxide for a period of 3 months. Serum level of key metabolic enzymes (α-amylase, α-glucosidase, hexokinase, glucose-6-phosphatase and HMG-CoA-reductase) was measured by ELISA method. BPA-exposure suppressed the mRNA expression of gene encoding insulin resulting in poor insulin production. While hexokinase, acetyl-CoA carboxylase and squalene epoxide were up-regulated upon BPA exposure that justified the increased lipid profile. Moreover, BPA exposure showed considerably decreased glucose uptake through insulin signaling via Akt/GLUT4 pathways. There was a significant (p < 0.001) reduction in tissue level of glucose transporters. BPA significantly (p < 0.001) decreased the serum levels of oxidative stress biomarkers (GSH, CAT, and SOD). Serum levels of leptin, TNF-α, and IL-6 were rapidly increased upon exposure to BPA (p < 0.001). It was clearly evident from this study that BPA disturbed the carbohydrate and lipid metabolism after chronic exposure. It also accelerated the inflammatory processes by increasing the oxidative stress which ultimately lead towards the insulin resistance and impaired carbohydrate and lipid metabolism.

Pdgfrα-Cre mediated knockout of the aryl hydrocarbon receptor protects mice from high-fat diet induced obesity and hepatic steatosis

Aryl hydrocarbon receptor (AHR) agonists such as dioxin have been associated with obesity and the development of diabetes. Whole-body Ahr knockout mice on high-fat diet (HFD) have been shown to resist obesity and hepatic steatosis. Tissue-specific knockout of Ahr in mature adipocytes via adiponectin-Cre exacerbates obesity while knockout in liver increases steatosis without having significant effects on obesity. Our previous studies demonstrated that treatment of subcutaneous preadipocytes with exogenous or endogenous AHR agonists disrupts maturation into functional adipocytes in vitro. Here, we used platelet-derived growth factor receptor alpha (Pdgfrα)-Cre mice, a Cre model previously established to knock out genes in preadipocyte lineages and other cell types, but not liver cells, to further define AHR's role in obesity. We demonstrate that Pdgfrα-Cre Ahr-floxed (Ahrfl/fl) knockout mice are protected from HFD-induced obesity compared to non-knockout Ahrfl/fl mice (control mice). The Pdgfrα-Cre Ahrfl/fl knockout mice were also protected from increased adiposity, enlargement of adipocyte size, and liver steatosis while on the HFD compared to control mice. On a regular control diet, knockout and non-knockout mice showed no differences in weight gain, indicating the protective phenotype arises only when animals are challenged by a HFD. At the cellular level, cultured cells from brown adipose tissue (BAT) of Pdgfrα-Cre Ahrfl/fl mice were more responsive than cells from controls to transcriptional activation of the thermogenic uncoupling protein 1 (Ucp1) gene by norepinephrine, suggesting an ability to burn more energy under certain conditions. Collectively, our results show that knockout of Ahr mediated by Pdgfrα-Cre is protective against diet-induced obesity and suggest a mechanism by which enhanced UCP1 activity within BAT might confer these effects.

Females are more susceptible than male mice to thermal hypernociceptive behavior induced by early-life bisphenol-A exposure: Effectiveness of diphenyl diselenide

Humans are ubiquitously exposed to bisphenol A (BPA), one of the most used synthetic monomers for manufacturing polycarbonate plastics. BPA exposure leads to abnormal nociceptive perception and neuroinflammation in rodents. This study investigated whether diphenyl diselenide (PhSe)₂, a pleiotropic selenium-containing molecule, would be effective against the hypernociceptive behavior induced by the early-life BPA exposure to mice. Three-week-old male and female Swiss mice received intragastrically BPA (5 mg/kg) from 21^st to 60^th postnatal day. After, the mice received by the intragastric route (PhSe)₂ (1 mg/kg) once a day for seven days. After the last day of treatment, the mice performed the hot plate and tail immersion tests. The cerebral cortex samples were used to determine the levels of proteins related to apoptosis and inflammation. The results demonstrated that females were more susceptible than male mice to thermal hypernociception induced by early-life exposure to BPA. (PhSe)₂ was effective against the reduction in the latency to paw and tail withdrawal induced by BPA exposure in female mice. Furthermore, (PhSe)₂ restored the impairment in the levels of inflammatory proteins (COX-2, IL-1β, and p-JNK/JNK) but not those of apoptosis in the cerebral cortex of female mice exposed to BPA. Collectively, these data showed that females were more susceptible to thermal hypernociceptive behavior induced by early-life exposure to BPA than male mice. The administration of (PhSe)₂ reduced thermal hypernociceptive behavior, a sex independent effect, in BPA-exposed mice. (PhSe)₂ modulated inflammatory protein levels in the cerebral cortex of female mice exposed to BPA.

Human exposure to bisphenol A through dietary sources and development of diabetes mellitus: a cross-sectional study in Pakistani population

Bisphenol A (BPA) is considered as xenoestrogen, a crucial component utilized for the manufacturing of plastic products. It has a potential to disrupt the endocrine system and induces endocrine-related metabolic disorders. We aimed to investigate the exposure of BPA in Pakistani population and its association with sociodemographic features, dietary habits, and risk factors of diabetes mellitus (DM). This cross-sectional study was conducted on 400 participants among which 61.75% participants were diabetic and 38.25% were non-diabetic. We developed a structured questionnaire, gathered sociodemographic data, and collected their urine and blood samples for the estimation of BPA and various biomarkers as risk factors of DM, respectively. Pearson correlation coefficient was determined for urinary BPA levels and DM risk factors. Urinary BPA values were adjusted for confounders. Sociodemographic data shown that urinary BPA level was significantly higher (p < 0.05) in obese people (BMI > 27) living in semi-urban and industrial areas. BPA was detectable in 75% of study participants. Urinary BPA level was found to be higher in diabetic participants compared with that of non-diabetics. A significant correlation is observed between BPA exposure and DM risk factors. We found that urinary BPA level was correlated with elevated levels of HbA1c (r = 0.6028), HOMA-IR (r = 0.5356), CRP (r = 0.6946), BUN (r = 0.6077), AST (r = 0.5151), FFA (r = 0.5759), TGs (r = 0.5608), and MDA (r = 0.6908). Hence, our study adds to the growing body of evidence supporting the role of BPA exposure as a risk factor for DM and may be associated with higher glycemic index, increased pro-inflammatory and oxidative stress biomarkers, dyslipidemia, and impaired functioning of the liver and kidney. Heating food in plastic containers and consumption of packed food items are the main sources of BPA exposure which are positively associated with DM.

Bisphenol A-induced metabolic disorders: From exposure to mechanism of action

Bisphenol A (BPA) is considered as ubiquitous xenooestrogen and an endocrine disrupting chemical which has deleterious effects on endocrine functions. Human populations are continuously exposed to BPA as it is abundant in daily life. It has been found to be associated with wide range of metabolic disorders notably type 2 diabetes mellitus (DM). Numerous epidemiological studies have been conducted to find its role in development of DM. Experimental studies have found that BPA exposure is associated with pathogenesis of DM and also considered as a risk factor for gestational diabetes. Being a lipophilic compound, BPA is preferably accumulated in adipose tissues where it alters the production of adipokines that play important roles in insulin resistance. BPA induces apoptosis by caspase activation after mitochondrial damage and it impairs insulin signaling pathways by altering associated ion channel activity especially potassium channels. Perinatal exposure of BPA makes offspring more susceptible to develop DM in early years. Epigenetic modifications are the key mechanisms for BPA-induced metabolic re-programming, where BPA alters the expression of DNA methyltransferases involved in methylation of various genes. In this way, DNA methyltransferase controls the expression of numerous genes including genes important for insulin secretion and signaling. Furthermore, BPA induces histone modifications and alters miRNA expression. In this article, we have briefly described the sources of BPA exposure to human being and summarized the evidence from epidemiological studies linking DM with BPA exposure. Additionally, we have also highlighted the potential molecular pathways for BPA-induced DM.

Adipose tissue concentrations of arsenic, nickel, lead, tin, and titanium in adults from GraMo cohort in Southern Spain: An exploratory study

BACKGROUND

Adipose tissue has been acknowledged as a potential target for obesogenic pollutants, including toxic metal(loid)s. However, the presence of these chemicals in the adipose tissue has been poorly characterized.

OBJECTIVE

To examine the distributions of adipose tissue concentrations of five toxic metal(loid)s (i.e., arsenic [As], nickel [Ni], lead [Pb], tin [Sn], and titanium [Ti]) in adults, and potential socio-demographic and lifestyle factors associated with metal(loid) concentrations.

METHODS

The study population consisted of a subsample of 228 subjects from GraMo cohort in Southern Spain (N = 387). Adipose tissue samples were intra-operatively collected from adults recruited in 2003-2004 in two public hospitals, and concentrations of metal(loid)s in adipose tissue were analyzed in 2015 by High-Resolution Inductively Coupled Plasma Mass Spectrometry. Data on socio-demographic and lifestyle factors were obtained by baseline questionnaire completion. Linear and multinomial regression was used to identify factors associated with metal(loid) levels.

RESULTS

Ni, Pb, Sn, and Ti were detected in all adipose tissue samples, and As in 51% of them. Ni was the metal showing the highest median concentration (0.56 μg/g), followed by Ti (0.31 μg/g), Pb (0.08 μg/g), Sn (0.06 μg/g), and As (0.003 μg/g). Predictors of As levels included area of residence, social class, and oily fish intake; for Ni: area of residence and consumption of cheese, meat, eggs, and canned food; for Pb: vegetables intake and industrial occupation; for Sn: age, body mass index, and consumption of lean fish, eggs, and milk; and cheese intake for Ti. Some of these predictors were sex-specific, particularly those regarding dietary intake.

CONCLUSIONS

This exploratory study provides the first evidence of the occurrence of Ni, Pb, Sn, Ti, and As in adipose tissue from adult population, and highlights the potential of this tissue as a biological matrix for studying exposure levels and chronic health effects of toxic metal(loid)s.

Severe dioxin-like compound (DLC) contamination in e-waste recycling areas: An under-recognized threat to local health

Electrical and electronic waste (e-waste) burning and recycling activities have become one of the main emission sources of dioxin-like compounds (DLCs). Workers involved in e-waste recycling operations and residents living near e-waste recycling sites (EWRS) are exposed to high levels of DLCs. Epidemiological and experimental in vivo studies have reported a range of interconnected responses in multiple systems with DLC exposure. However, due to the compositional complexity of DLCs and difficulties in assessing mixture effects of the complex mixture of e-waste-related contaminants, there are few studies concerning human health outcomes related to DLC exposure at informal EWRS. In this paper, we have reviewed the environmental levels and body burdens of DLCs at EWRS and compared them with the levels reported to be associated with observable adverse effects to assess the health risks of DLC exposure at EWRS. In general, DLC concentrations at EWRS of many countries have been decreasing in recent years due to stricter regulations on e-waste recycling activities, but the contamination status is still severe. Comparison with available data from industrial sites and well-known highly DLC contaminated areas shows that high levels of DLCs derived from crude e-waste recycling processes lead to elevated body burdens. The DLC levels in human blood and breast milk at EWRS are higher than those reported in some epidemiological studies that are related to various health impacts. The estimated total daily intakes of DLCs for people in EWRS far exceed the WHO recommended total daily intake limit. It can be inferred that people living in EWRS with high DLC contamination have higher health risks. Therefore, more well-designed epidemiological studies are urgently needed to focus on the health effects of DLC pollution in EWRS. Continuous monitoring of the temporal trends of DLC levels in EWRS after actions is of highest importance.

The GOLIATH Project: Towards an Internationally Harmonised Approach for Testing Metabolism Disrupting Compounds

The purpose of this project report is to introduce the European "GOLIATH" project, a new research project which addresses one of the most urgent regulatory needs in the testing of endocrine-disrupting chemicals (EDCs), namely the lack of methods for testing EDCs that disrupt metabolism and metabolic functions. These chemicals collectively referred to as "metabolism disrupting compounds" (MDCs) are natural and anthropogenic chemicals that can promote metabolic changes that can ultimately result in obesity, diabetes, and/or fatty liver in humans. This project report introduces the main approaches of the project and provides a focused review of the evidence of metabolic disruption for selected EDCs. GOLIATH will generate the world's first integrated approach to testing and assessment (IATA) specifically tailored to MDCs. GOLIATH will focus on the main cellular targets of metabolic disruption-hepatocytes, pancreatic endocrine cells, myocytes and adipocytes-and using an adverse outcome pathway (AOP) framework will provide key information on MDC-related mode of action by incorporating multi-omic analyses and translating results from in silico, in vitro, and in vivo models and assays to adverse metabolic health outcomes in humans at real-life exposures. Given the importance of international acceptance of the developed test methods for regulatory use, GOLIATH will link with ongoing initiatives of the Organisation for Economic Development (OECD) for test method (pre-)validation, IATA, and AOP development.

Oxidative Stress and BPA Toxicity: An Antioxidant Approach for Male and Female Reproductive Dysfunction

Bisphenol A (BPA) is a non-persistent anthropic and environmentally ubiquitous compound widely employed and detected in many consumer products and food items; thus, human exposure is prolonged. Over the last ten years, many studies have examined the underlying molecular mechanisms of BPA toxicity and revealed links among BPA-induced oxidative stress, male and female reproductive defects, and human disease. Because of its hormone-like feature, BPA shows tissue effects on specific hormone receptors in target cells, triggering noxious cellular responses associated with oxidative stress and inflammation. As a metabolic and endocrine disruptor, BPA impairs redox homeostasis via the increase of oxidative mediators and the reduction of antioxidant enzymes, causing mitochondrial dysfunction, alteration in cell signaling pathways, and induction of apoptosis. This review aims to examine the scenery of the current BPA literature on understanding how the induction of oxidative stress can be considered the "fil rouge" of BPA's toxic mechanisms of action with pleiotropic outcomes on reproduction. Here, we focus on the protective effects of five classes of antioxidants-vitamins and co-factors, natural products (herbals and phytochemicals), melatonin, selenium, and methyl donors (used alone or in combination)-that have been found useful to counteract BPA toxicity in male and female reproductive functions.

Drug Delivery Strategies for Enhancing the Therapeutic Efficacy of Toxin-Derived Anti-Diabetic Peptides

Toxin peptides derived from the skin secretions of amphibians possess unique hypoglycemic activities. Many of these peptides share cationic and amphipathic structural similarities and appear to possess cell-penetrating abilities. The mechanism of their insulinotropic action is yet not elucidated, but they have shown great potential in regulating the blood glucose levels in animal models. Therefore, they have emerged as potential drug candidates as therapeutics for type 2 diabetes. Despite their anti-diabetic activity, there remain pharmaceutical challenges to be addressed for their clinical applications. Here, we present an overview of recent studies related to the toxin-derived anti-diabetic peptides derived from the skin secretions of amphibians. In the latter part, we introduce the bottleneck challenges for their delivery in vivo and general drug delivery strategies that may be applicable to extend their blood circulation time. We focus our research on the strategies that have been successfully applied to improve the plasma half-life of exendin-4, a clinically available toxin-derived anti-diabetic peptide drug.

Potentilla rugulosa Nakai Extract Attenuates Bisphenol A-, S- and F-Induced ROS Production and Differentiation of 3T3-L1 Preadipocytes in the Absence of Dexamethasone

Endocrine disrupting chemicals (EDCs) disrupt the physiological metabolism, thus playing an important role in the development of obesity. EDCs, the so-called ‘obesogens’, might predispose some individuals to gain weight. This study investigated the effects of bisphenol A (BPA) and its alternatives (BPS and BPF) on adipocyte differentiation and the effects of the leaves of Potentilla rugulosa Nakai extract (LPE) as a functional food ingredient on obesogen-induced lipid production and adipogenesis in 3T3-L1 cells. The results showed that LPE has high total phenolic and flavonoid contents (77.58 ± 0.57 mg gallic acid equivalents (GAE)/g and 57.31 ± 1.72 mg quercetin equivalents (QE)/g, respectively). In addition, LPE exerted significant antioxidant effects in terms of DPPH radical scavenging activity, reducing power, ferric-ion reducing antioxidant power, and oxygen radical absorbance capacity. BPA, BPS, and BPF increased lipid accumulation, protein expressions of adipogenic transcription factors (PPAR-γ, C/EBP-α, and aP2), and reactive oxygen species (ROS) production in 3T3-L1 cells. However, LPE suppressed the BPA-, BPS-, and BPF-induced effects on adipogenesis. Therefore, LPE has potential as a functional food supplement that can prevent bisphenol-induced lipid metabolism disorders.

Impaired fasting glucose prevalence surge among Iranian adolescents in a decade: The Tehran Lipid and Glucose Study

PURPOSE

Impaired fasting glucose (IFG) is associated with incident diabetes, cardiovascular risk, and markers of atherosclerosis in early adulthood. We aimed to explore the 10-year change in IFG prevalence among adolescent participants of the Tehran Lipid and Glucose Study, a population-based study from Iran.

METHODS

For our study, we used data on fasting plasma glucose (FPG), anthropometric, and demographic information of 11 to 19-year-old adolescents in study periods I (1999-2005; 1415 boys, 1583 girls) and II (2011-2014; 477 boys, 469 girls). Sex-adjusted and sex-stratified multivariable logistic regression models were used to assess the relationship of the study period (reference: study period I) with IFG.

RESULTS

The prevalence of IFG, general obesity, and central obesity increased from 7%, 13.3%, and 18.8% in study period I to 16.6%, 24%, and 37.4% in study period II; while a favorable trend was seen for blood pressure, triglycerides, and high-density lipoprotein cholesterol. In the fully adjusted model, being older (age group 15-19 vs 11-14 years) and female sex were associated with lower risk. Being overweight and obese increased the risk by risk ratios (confidence interval) of 1.57 (1.17-2.11) and 1.63 (1.15-2.30), respectively. Central adiposity did not remain as an independent risk factor. Nevertheless, study period persisted as a significant factor despite all adjustments [2.20 (1.81-2.68)]. Results in the sex-stratified models were generally the same.

CONCLUSION

Our results demonstrated that the over 2-fold rise in IFG prevalence among adolescents was not solely dependent on general and central obesity.

Intrauterine programming of obesity and type 2 diabetes

The type 2 diabetes epidemic and one of its predisposing factors, obesity, are major influences on global health and economic burden. It is accepted that genetics and the current environment contribute to this epidemic; however, in the last two decades, both human and animal studies have consolidated considerable evidence supporting the 'developmental programming' of these conditions, specifically by the intrauterine environment. Here, we review the various in utero exposures that are linked to offspring obesity and diabetes in later life, including epidemiological insights gained from natural historical events, such as the Dutch Hunger Winter, the Chinese famine and the more recent Quebec Ice Storm. We also describe the effects of gestational exposure to endocrine disruptors, maternal infection and smoking to the fetus in relation to metabolic programming. Causal evidence from animal studies, motivated by human observations, is also discussed, as well as some of the proposed underlying molecular mechanisms for developmental programming of obesity and type 2 diabetes, including epigenetics (e.g. DNA methylation and histone modifications) and microRNA interactions. Finally, we examine the effects of non-pharmacological interventions, such as improving maternal dietary habits and/or increasing physical activity, on the offspring epigenome and metabolic outcomes.