Pilot Study on the Effect of Orally Administered Bisphenol A on Glucose and Insulin Response in Nonobese Adults

Exposure to low dose of Bisphenol A (BPA) intensifies kidney oxidative stress, inflammatory factors expression and modulates Angiotensin II signaling under hypertensive milieu

Humans are constantly exposed to low concentrations of ubiquitous environmental pollutant, Bisphenol A (BPA). Due to the prevalence of hypertension (one of the major risk factors of cardiovascular disease [CVD]) in the population, it is necessary to explore the adverse effect of BPA under hypertension associated pathogenic milieu. The current study exposed the Nω-nitro-l-arginine methyl ester (L-NAME) induced hypertensive Wistar rats to low dose BPA (50 μg/kg) for 30 days period. In tissue samples immunohistochemistry, real-time quantitative polymerase chain reaction and enzymatic assays were conducted. Moreover, studies on primary kidney cell culture were employed to explore the impact of low dose of BPA exposure at nanomolar level (20-80 nM range) on renal cells through various fluorescence assays. The observed results illustrate that BPA exposure potentiates/aggravates hypertension induced tissue abnormalities (renal fibrosis), oxidative stress (ROS generation), elevated angiotensin-converting enzyme activity, malfunction of the antioxidant and tricarboxylic acid cycle enzymes, tissue lipid abnormalities and inflammatory factor expression (both messenger RNA and protein level of TNF-α and IL-6). Further, in vitro exposure of nM levels of BPA to primary kidney cells modulates oxidative stress (both superoxide and total ROS), mitochondrial physiology (reduced mitochondrial transmembrane potential-∆ψm) and lipid peroxidation in a dose dependent manner. In addition, angiotensin II induced ROS generation was aggravated further by BPA during coexposure in kidney cells. Therefore, during risk assessment, a precise investigation on BPA exposure in hypertensive (CVD vulnerable) populations is highly suggested.

Comparative G-Protein-Coupled Estrogen Receptor (GPER) Systems in Diabetic and Cancer Conditions: A Review

For many patients, diabetes Mellitus and Malignancy are frequently encountered comorbidities. Diabetes affects approximately 10.5% of the global population, while malignancy accounts for 29.4 million cases each year. These troubling statistics indicate that current treatment approaches for these diseases are insufficient. Alternative therapeutic strategies that consider unique signaling pathways in diabetic and malignancy patients could provide improved therapeutic outcomes. The G-protein-coupled estrogen receptor (GPER) is receiving attention for its role in disease pathogenesis and treatment outcomes. This review aims to critically examine GPER' s comparative role in diabetes mellitus and malignancy, identify research gaps that need to be filled, and highlight GPER's potential as a therapeutic target for diabetes and malignancy management. There is a scarcity of data on GPER expression patterns in diabetic models; however, for diabetes mellitus, altered expression of transport and signaling proteins has been linked to GPER signaling. In contrast, GPER expression in various malignancy types appears to be complex and debatable at the moment. Current data show inconclusive patterns of GPER expression in various malignancies, with some indicating upregulation and others demonstrating downregulation. Further research should be conducted to investigate GPER expression patterns and their relationship with signaling pathways in diabetes mellitus and various malignancies. We conclude that GPER has therapeutic potential for chronic diseases such as diabetes mellitus and malignancy.

Obesity II: Establishing causal links between chemical exposures and obesity

Obesity is a multifactorial disease with both genetic and environmental components. The prevailing view is that obesity results from an imbalance between energy intake and expenditure caused by overeating and insufficient exercise. We describe another environmental element that can alter the balance between energy intake and energy expenditure: obesogens. Obesogens are a subset of environmental chemicals that act as endocrine disruptors affecting metabolic endpoints. The obesogen hypothesis posits that exposure to endocrine disruptors and other chemicals can alter the development and function of the adipose tissue, liver, pancreas, gastrointestinal tract, and brain, thus changing the set point for control of metabolism. Obesogens can determine how much food is needed to maintain homeostasis and thereby increase the susceptibility to obesity. The most sensitive time for obesogen action is in utero and early childhood, in part via epigenetic programming that can be transmitted to future generations. This review explores the evidence supporting the obesogen hypothesis and highlights knowledge gaps that have prevented widespread acceptance as a contributor to the obesity pandemic. Critically, the obesogen hypothesis changes the narrative from curing obesity to preventing obesity.

Exposure to a "safe" dose of environmental pollutant bisphenol A elevates oxidative stress and modulates vasoactive system in hypertensive rats

Due to the prevalence of hypertension (one of the major risk factors of CVD) in the population, it is necessary to explore the adverse effects of daily tolerable and "safe" dose of bisphenol A (BPA) under hypertensive conditions. The current study exposed the Nω-nitro-l-arginine methyl ester (L-NAME, 40 mg/kg b.w/day) induced hypertensive Wistar rats to BPA (50 μg/kg b.w/day) by oral administration along with appropriate controls for 30 days period. The results illustrate that a 'safe' dose of BPA does not influence the systolic blood pressure (SBP) and levels of circulatory biomarkers of tissue damage. On the other hand, BPA exposure significantly (p < 0.05) elevates the thiobarbituric acid reactive substances (TBARS) content in plasma and tissues (heart, aorta, liver and kidney) in hypertensive rats when compared with respective control (BPA alone exposed) rats. Similarly, a significant modulation of ROS generation in RBC, plasma nitric oxide (NO) level and angiotensin-converting enzyme (ACE) activity was observed only under hypertensive milieu. In conclusion, the observed adverse effects during 'safe' dose of BPA exposure are specific to the hypertensive condition. Therefore, a precise investigation to explore the effects of BPA exposure in vulnerable hypertensive populations is highly suggested.

Trends in diabetes care with special emphasis to medicinal plants: Advancement and treatment

Diabetic mellitus (DM) is a common metabolic disorder prevailing throughout the world. It may affect a child to an older person depending upon the physiology and the factors influencing the internal metabolic system of the body. Several treatments are available in the market ranges from synthetic drugs, insulin therapy, herbal drugs, and transdermal patches. Interestingly, the development of technologies and digital health have proving very helpful in improving the lifestyle of diabetic patients. All treatment approaches have their own advantages and disadvantages in the form of effectiveness and side effects. Medicinal plants have a long history of traditional application in the treatment of diabetes and even the use of plants are growing day-by-day due to the significant results against diseases and fewer side effects as compared to other treatment therapies. The intention behind writing this review is to gather all information and discussed them exhaustively in an article. The novel Coronavirus 2019 (COVID-19) pandemic has affected my lives including diabetic patients. The antidiabetic treatment strategies during this period has also discussed. In this article, we highlighted the molecular mechanism and herbal phytoconstituents that are responsible for lowering blood glucose level. The factors responsible for the progression of metabolic disorders can be controlled with the use of phytoconstituents present in herbal plants to maintain β-cells performance and restore blood glucose level. It can be concluded that medicinal plants are effective and affordable with lesser side effects for treating DM.

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.

Rationale and design of a randomized controlled trial examining oral administration of bisphenol A on hepatic glucose production and skeletal muscle insulin sensitivity in adults

Previous observational studies have shown that the endocrine disrupting chemical bisphenol A (BPA) is associated with type 2 diabetes, but few studies have examined direct effects of BPA on human health. The purpose of this study is to determine whether orally administered BPA at the US Environmental Protection Agency (EPA) safe dose of 50 μg/kg body weight has an adverse effect on hepatic glucose production and skeletal muscle insulin sensitivity. Forty, non-habitually active, healthy adults of normal weight will be enrolled. Participants will begin with a 2-day baseline energy balance diet low in bisphenols in which urine and blood will be collected, and standard tests performed to assess the primary outcome measures of hepatic glucose production (via [6,6-²H] glucose infusion) and skeletal muscle insulin sensitivity (via euglycemic hyperinsulinemic clamp technique). Secondary outcome measures are fasting hormones/endocrine factors (insulin, glucose, C-peptide, Pro-insulin, adiponectin, 17-beta-estradiol, free fatty acids) related to the pathogenesis of type 2 diabetes. Participants will then be randomly assigned to a 4-day energy balance diet plus oral administration of BPA at 50 μg/kg body weight (Diet + BPA) or 4-day energy balance diet plus oral administration of placebo (Diet + No BPA); all outcome measures will be reassessed after 4 days. Findings from this study will provide a framework for other studies in this area, and provide much needed experimental evidence using gold standard measures as to whether oral BPA administration over several days poses any risk of type 2 diabetes.

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Bisphenol A is associated with type 2 diabetes.

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Few studies have examined oral bisphenol A administration on the pathogenesis of type 2 diabetes.

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This study will examine oral bisphenol A administration on hepatic glucose [6,6-²H] suppression.

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This study will examine insulin sensitivity (euglycemic hyperinsulinemic clamp technique).

Environmental neglect: endocrine disruptors as underappreciated but potentially modifiable diabetes risk factors

Type 2 diabetes prevalence is increasing dramatically across the globe, imposing a tremendous toll on individuals and healthcare systems. Reversing these trends requires comprehensive approaches to address both classical and emerging diabetes risk factors. Recently, environmental toxicants acting as endocrine-disrupting chemicals (EDCs) have emerged as novel metabolic disease risk factors. EDCs implicated in diabetes pathogenesis include various inorganic and organic molecules of both natural and synthetic origin, including arsenic, bisphenol A, phthalates, polychlorinated biphenyls and organochlorine pesticides. Indeed, evidence implicates EDC exposures across the lifespan in metabolic dysfunction; moreover, specific developmental windows exhibit enhanced sensitivity to EDC-induced metabolic disruption, with potential impacts across generations. Importantly, differential exposures to diabetogenic EDCs likely also contribute to racial/ethnic and economic disparities. Despite these emerging links, clinical practice guidelines fail to address this underappreciated diabetes risk factor. Comprehensive approaches to stem the tide of diabetes must include efforts to address its environmental drivers.

CLARITY-BPA Program in Rats: Is It Translatable to Humans?

The Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA) program was the most comprehensive study to date examining a full range of health effects of varying bisphenol A (BPA) exposure in rats. The major concern of the CLARITY-BPA program that has not previously been discussed is whether exposing rats to varying doses to BPA is translatable to humans, even at the “typical” exposure ranges for humans. This perspective will provide evidence that the vast majority of pharmaceutical drug development and other trials in animals have not been replicated in human randomized studies. Similarly, to truly understand whether BPA exposure affects human health, clinical trials are needed to examine BPA administration in humans in controlled settings.