Bisphenol A stimulates steroidogenic acute regulatory protein expression via an unknown mechanism in adrenal cortical cells

Detrimental consequences of micropolymers associated plasticizers on endocrinal disruption

The prevalence of polymer usage in everyday activities has emerged as a detriment to both human life and the environment. A large number of studies describe severe impacts of micropolymers (MP) and nanopolymers (NP) on various organ systems, including the endocrine system. Additionally, plasticizers utilized as additives have been identified as endocrine-disrupting chemicals (EDCs). MP/NP, along with associated plasticizers, affect principal signalling pathways of endocrine glands such as the pituitary, thyroid, adrenal, and gonads, thereby disrupting hormone function and metabolic processes crucial for maintaining homeostasis, fertility, neural development, and fetal growth. This review delves into the sources, distribution, and effects of micropolymers, nanopolymers, and associated plasticizers acting as EDCs. Furthermore, it provides a detailed review of the mechanisms underlying endocrine disruption in relation to different types of MP/NP.

Endocrine Disruptors: Focus on the Adrenal Cortex

Endocrine-disrupting chemicals (EDCs) are exogenous substances known to interfere with endocrine homeostasis and promote adverse health outcomes. Their impact on the adrenal cortex, corticosteroids and their physiological role in the organism has not yet been sufficiently elucidated. In this review, we collect experimental and epidemiological evidence on adrenal disruption by relevant endocrine disruptors. In vitro data suggest significant alterations of gene expression, cell signalling, steroid production, steroid distribution, and action. Additionally, morphological studies revealed disturbances in tissue organization and development, local inflammation, and zone-specific hyperplasia. Finally, endocrine circuits, such as the hypothalamic-pituitary-adrenal axis, might be affected by EDCs. Many questions regarding the detection of steroidogenesis disruption and the effects of combined toxicity remain unanswered. Not only due to the diverse mode of action of adrenal steroids and their implication in many common diseases, there is no doubt that further research on endocrine disruption of the adrenocortical system is needed.

A Brief Look at Hashimoto's Disease, Adrenal Incidentalomas, Obesity and Insulin Resistance-Could Endocrine Disruptors Be the Other Side of the Same Coin?

Hashimoto's disease (HD) is the most common cause of hypothyroidism in developed countries. The exact pathomechanism behind it has not been clearly established; however, an interplay of genetic susceptibility, environmental triggers (including diet) and epigenetic factors seems to be involved. Among the latter, increasingly more attention has been paid to some hormonally active substances, known as endocrine disruptors, which are commonly used worldwide. HD has become a condition widely reported in the media, acting as a culprit for inexplicable weight gain, chronic fatigue or weakness. Nevertheless, the recognition of HD is undeniably increasing and represents a major public health burden. At the same time, improving access to imaging tests has increased the number of incidentally diagnosed adrenal tumors. Above all, the widespread use of chest computed tomography (CT) due to the COVID-19 pandemic has contributed to frequent incidental detection of adrenal lesions. Fortunately, a vast majority of these findings are asymptomatic benign tumors with no excessive hormonal activity, and therefore, they are defined as adrenal incidentalomas (AIs). Interestingly, recent studies have indicated that patients with AIs are more prone to obesity and insulin resistance. Although mutual relationships between the thyroid and the adrenal glands have been studied widely, still, little is known about the possible pathophysiological associations between thyroid autoimmunity and the occurrence of adrenal incidentalomas. This article presents a brief review of the common endocrine disorders with a special focus on the frequently coexisting insulin resistance and/or obesity. Furthermore, in response to the recent growing interest in endocrine disruptors, with their transgenerational epigenetic effects that influence hormonal system function, a concise overview of the topic has also been included.

Nonfunctional adrenal incidentalomas may be related to bisphenol-A

PURPOSE

Bisphenol-A (BPA) is an endocrine-disrupting chemical that may affect the hormones and their receptors. The aim of this study is to determine whether BPA has an effect on the development of nonfunctional adrenal incidentaloma (NFAI).

METHODS

Fifty patients who were admitted to endocrinology outpatient clinics and diagnosed as NFAI were included in the study. Fifty healthy people without adrenal mass and adrenal pathology in the upper abdominal computerized tomography or magnetic resonance imaging were also included as control group. Age, gender and body mass index of the study groups were similar. The serum samples for BPA were stored at -80 °C in refrigerator until working in the lab. Serum BPA levels were measured using ELISA technique.

RESULTS

Mean serum BPA level was 7.06 ± 3.96 ng/ml in NFAI patients and 4.79 ± 3.01 ng/ml in control group. Serum BPA level was significantly higher in NFAI group than control group (p = 0.001). Serum BPA levels were also found to be significantly higher in women with NFAI than in men with NFAI (p = 0.019).

CONCLUSIONS

The mechanisms of NFAI development have not been clarified yet. Increased BPA exposure with developed industrialization may play a role in NFAI formation. For the reduction of BPA exposure, the use of plastic prepacked products, plastic containers, and safety measures are essential for public health.

Bisphenol A decreases progesterone synthesis in human ovarian granulosa cells

Evidences indicate that the decline of female fertility is becoming a common problem over the past few decades. Environmental exposure of Bisphenol A (BPA) has been considered as an endocrine-disrupting chemical deleteriously affecting human reproductions. To better understand the effect of BPA exposure on human ovarian granulosa cells, we treated human ovarian granulosa cell line (KGN) with increasing concentrations (0.1, 1, 10, and 100 μM) of BPA for 24 hr. About 0.1, 1, and 10 μM BPA did not significantly affect the viability of KGN while 100 μM of BPA caused a statistically significant decrease in the viability of KGN. Treatment KGN with 10 μM BPA resulted in a significant decrease in progesterone biosynthesis. The treatment also significantly increased the expression of ATP binding cassette subfamily A member 1 (ABCA1) and steroidogenic acute regulatory protein (STAR). In the current study, exposure to BPA could lead to decreased progesterone production probably through the upregulation of ABCA1 in human granulosa cells.

BPA interferes with StAR-mediated mitochondrial cholesterol transport to induce germline dysfunctions

Bisphenol A is an endocrine disruptor associated with hormone synthesis and reproduction alterations. However, the initiating events underpinning these dysfunctions are still unclear. Here, we address the hypothesis that BPA interferes with the highly evolutionary conserved process of mitochondrial cholesterol transport, a crucial step in steroid hormone biosynthesis, by using the model organism C. elegans. We observed that embryonic lethality and germline apoptosis, hallmarks of BPA's reproductive toxicity in C. elegans, are fully rescued by low exogenous cholesterol supplementation. We also observed that increasing BPA concentrations proportionally reduced mitochondrial cholesterol levels. Mutants for strl-1 (ortholog of StAR), but not C41G7.9 (ortholog of TSPO), show reproductive defects similar to BPA's while BPA exposure in a strl-1 background did not worsen these effects. Finally, cholesterol supplementation rescued these defects for all strl-1 genotype/BPA combinations assessed. Together, these results uncover a novel mechanism underlying BPA's germline toxicity through the alteration of cholesterol transport.