Endocrine-disrupting chemicals and skin manifestations

Novel Therapeutic Hybrid Systems Using Hydrogels and Nanotechnology: A Focus on Nanoemulgels for the Treatment of Skin Diseases

Topical and transdermal drug delivery are advantageous administration routes, especially when treating diseases and conditions with a skin etiology. Nevertheless, conventional dosage forms often lead to low therapeutic efficacy, safety issues, and patient noncompliance. To tackle these issues, novel topical and transdermal platforms involving nanotechnology have been developed. This review focuses on the latest advances regarding the development of nanoemulgels for skin application, encapsulating a wide variety of molecules, including already marketed drugs (miconazole, ketoconazole, fusidic acid, imiquimod, meloxicam), repurposed marketed drugs (atorvastatin, omeprazole, leflunomide), natural-derived compounds (eucalyptol, naringenin, thymoquinone, curcumin, chrysin, brucine, capsaicin), and other synthetic molecules (ebselen, tocotrienols, retinyl palmitate), for wound healing, skin and skin appendage infections, skin inflammatory diseases, skin cancer, neuropathy, or anti-aging purposes. Developed formulations revealed adequate droplet size, PDI, viscosity, spreadability, pH, stability, drug release, and drug permeation and/or retention capacity, having more advantageous characteristics than current marketed formulations. In vitro and/or in vivo studies established the safety and efficacy of the developed formulations, confirming their therapeutic potential, and making them promising platforms for the replacement of current therapies, or as possible adjuvant treatments, which might someday effectively reach the market to help fight highly incident skin or systemic diseases and conditions.

Development of skin diseases following systemic exposure: example of dioxins

Most skin manifestations of exposure to toxic compounds are a consequence of a direct contact with the toxicants. However, some toxicants may reach the skin following systemic exposure, and promote skin diseases. Good examples of such chemicals are dioxin-like compounds. This family of lipophilic molecules comprises polychlorinated (dibenzodioxins, dibenzofurans and biphenyls). The most potent member of this family is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Following oral ingestion of as little as a few mg TCDD, skin lesions appear in a couple of weeks, starting from the face and diffuse then on the trunk and limbs. This syndrome was historically called "chloracne" and the skin lesions have now been shown to be skin hamartoma induced by TCDD. Sweat glands release their lipid content on the surface of the skin by a holocrine secretion, and so any lost sebocyte should be transmitted to progenitor cells to differentiate and migrate to the sebaceous gland to replace the lost sebocyte. TCDD acts by inducing a switch in this signal and skin hamartoma develop in place of new sebocytes.

Estrogenic potency of endocrine disrupting chemicals and their mixtures detected in environmental waters and wastewaters

Endocrine disrupting chemicals such as natural and synthetic steroid hormones and bisphenols are among the most important pollutants in the aquatic environment. We performed an environmental chemical analysis of five Slovenian water samples, two rivers, one groundwater, and the influent and effluent of wastewater treatment plants, with a highly sensitive analysis of twenty-five endocrine-disrupting compounds belonging to the groups of natural hormones, synthetic hormones, and bisphenols. Since these compounds are simultaneously present in the environment, it is important to study their individual effects as well as the effects of mixtures. We investigated in vitro the estrogenic potency of selected natural and synthetic steroid hormones and bisphenols detected in surface, ground and waste water in Slovenia using the OECD-validated transactivation assay on the cell line Hela9903. We predicted their mixture effects using the concentration addition model and compared them with experimentally determined values. Two mixing designs were used: a balanced design in which chemicals were combined in proportion to their individual EC₅₀ values, and an unbalanced design with compounds in proportion to their measured concentrations in the environmental samples. The estrogenic effects of the experimental mixtures followed the concentration addition model. Real water samples exhibited weaker estrogenic effects, showing the great heterogeneity of the real water samples.

Sebaceous immunobiology - skin homeostasis, pathophysiology, coordination of innate immunity and inflammatory response and disease associations

This review presents several aspects of the innovative concept of sebaceous immunobiology, which summarizes the numerous activities of the sebaceous gland including its classical physiological and pathophysiological tasks, namely sebum production and the development of seborrhea and acne. Sebaceous lipids, which represent 90% of the skin surface lipids in adolescents and adults, are markedly involved in the skin barrier function and perifollicular and dermal innate immune processes, leading to inflammatory skin diseases. Innovative experimental techniques using stem cell and sebocyte models have clarified the roles of distinct stem cells in sebaceous gland physiology and sebocyte function control mechanisms. The sebaceous gland represents an integral part of the pilosebaceous unit and its status is connected to hair follicle morphogenesis. Interestingly, professional inflammatory cells contribute to sebocyte differentiation and homeostasis, whereas the regulation of sebaceous gland function by immune cells is antigen-independent. Inflammation is involved in the very earliest differentiation changes of the pilosebaceous unit in acne. Sebocytes behave as potent immune regulators, integrating into the innate immune responses of the skin. Expressing inflammatory mediators, sebocytes also contribute to the polarization of cutaneous T cells towards the Th17 phenotype. In addition, the immune response of the perifollicular infiltrate depends on factors produced by the sebaceous glands, mostly sebaceous lipids. Human sebocytes in vitro express functional pattern recognition receptors, which are likely to interact with bacteria in acne pathogenesis. Sex steroids, peroxisome proliferator-activated receptor ligands, neuropeptides, endocannabinoids and a selective apoptotic process contribute to a complex regulation of sebocyte-induced immunological reaction in numerous acquired and congenital skin diseases, including hair diseases and atopic dermatitis.

Role of ER Stress in Xenobiotic-Induced Liver Diseases and Hepatotoxicity

The liver is a highly metabolic organ and plays a crucial role in the transportation, storage, and/or detoxication of xenobiotics. Liver damage induced by xenobiotics (e.g., heavy metal, endocrine disrupting chemicals, Chinese herbal medicine, or nanoparticles) has become a pivotal reason for liver diseases, leading to great clinical challenge and much attention for the past decades. Given that endoplasmic reticulum (ER) is the prominent organelle involved in hepatic metabolism, ER dysfunction, namely, ER stress, is clearly observed in various liver diseases. In response to ER stress, a conserved adaptive signaling pathway known as unfolded protein response (UPR) is activated to restore ER homeostasis. However, the prolonged ER stress with UPR eventually leads to the death of hepatocytes, which is a pathogenic event in many hepatic diseases. Therefore, analyzing the perturbation in the activation or inhibition of ER stress and the UPR signaling pathway is likely an effective marker for investigating the molecular mechanisms behind the toxic effects of xenobiotics on the liver. We review the role of ER stress in hepatic diseases and xenobiotic-induced hepatotoxicity, which not only provides a theoretical basis for further understanding the pathogenesis of liver diseases and the mechanisms of hepatotoxicity induced by xenobiotics but also presents a potential target for the prevention and treatment of xenobiotic-related liver diseases.

Grifola frondosa Extract Containing Bioactive Components Blocks Skin Fibroblastic Inflammation and Cytotoxicity Caused by Endocrine Disrupting Chemical, Bisphenol A

Grifola frondosa (GF), a species of Basidiomycotina, is widely distributed across Asia and has been used as an immunomodulatory, anti-bacterial, and anti-cancer agent. In the present study, the pharmacological activity of the GF extract against an ecotoxicological industrial chemical, bisphenol A (BPA) in normal human dermal fibroblasts (NHDFs), was investigated. GF extract containing naringin, hesperidin, chlorogenic acid, and kaempferol showed an inhibitory effect on cell death and inflammation induced by BPA in the NHDFs. For the cell death caused by BPA, GF extract inhibited the production of reactive oxygen species responsible for the unique activation of the extracellular signal-regulated kinase. In addition, GF extract attenuated the expression of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) and the pro-inflammatory cytokine IL-1β by the suppression of the redox-sensitive transcription factor, nuclear factor-kappa B (NF-κB) in BPA-treated NHDFs. For the inflammation triggered by BPA, GF extract blocked the inflammasome-mediated caspase-1 activation that leads to the secretion of IL-1β protein. These results indicate that the GF extract is a functional antioxidant that prevents skin fibroblastic pyroptosis induced by BPA.

Pregnant Women and Endocrine Disruptors: Role of P2X7 Receptor and Mitochondrial Alterations in Placental Cell Disorders

In pregnant women, the lungs, skin and placenta are exposed daily to endocrine-disrupting chemicals (EDCs). EDCs induce multiple adverse effects, not only on endocrine organs, but also on non-endocrine organs, with the P2X7 cell death receptor being potentially the common key element. Our objective was first to investigate mechanisms of EDCs toxicity in both endocrine and non-endocrine cells through P2X7 receptor activation, and second, to compare the level of activation in lung, skin and placental cells. In addition, apoptosis in placental cells was studied because the placenta is the most exposed organ to EDCs and has essential endocrine functions. A total of nine EDCs were evaluated on three human cell models. We observed that the P2X7 receptor was not activated by EDCs in lung non-endocrine cells but was activated in skin and placenta cells, with the highest activation in placenta cells. P2X7 receptor activation and apoptosis are pathways shared by all tested EDCs in endocrine placental cells. P2X7 receptor activation along with apoptosis induction could be key elements in understanding endocrine placental and skin disorders induced by EDCs.

EDC-induced mechanisms of immunotoxicity: a systematic review

Endocrine-disrupting chemicals (EDCs) refer to a group of chemicals that cause adverse effects in human health, impairing hormone production and regulation, resulting in alteration of homeostasis, reproductive, and developmental, and immune system impairments. The immunotoxicity of EDCs involves many mechanisms altering gene expression that depend on the activation of nuclear receptors such as the aryl hydrocarbon receptor (AHR), the estrogen receptor (ER), and the peroxisome proliferator-activated receptor (PPAR), which also results in skin and intestinal disorders, microbiota alterations and inflammatory diseases. This systematic review aims to review different mechanisms of immunotoxicity and immunomodulation of T cells, focusing on T regulatory (Treg) and Th17 subsets, B cells, and dendritic cells (DCs) caused by specific EDCs such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), bisphenols (BPs) and polyfluoroalkyl substances (PFASs). To achieve this objective, a systematic study was conducted searching various databases including PubMed and Scopus to find in-vitro, in-vivo, and biomonitoring studies that examine EDC-dependent mechanisms of immunotoxicity. While doing the systematic review, we found species- and cell-specific outcomes and a translational gap between in-vitro and in-vivo experiments. Finally, an adverse outcome pathway (AOP) framework is proposed, which explains mechanistically toxicity endpoints emerging from different EDCs having similar key events and can help to improve our understanding of EDCs mechanisms of immunotoxicity. In conclusion, this review provides insights into the mechanisms of immunotoxicity mediated by EDCs and will help to improve human health risk assessment.

Could endocrine disruptors be a new player for acne pathogenesis? The effect of bisphenol A on the formation and severity of acne vulgaris: A prospective, case-controlled study

BACKGROUND

Acne is one of the most common skin diseases in the adolescent period. Bisphenol A (BPA) is the most frequently observed endocrine-disrupting chemicals that we are exposed to in daily life. BPA can affect acne pathogenesis with similar biological activity on androgenic receptors.

AIMS

To investigate whether BPA levels play a role in the development and severity of acne in adults.

METHODS

Fifty-one adults with acne and 50 healthy controls, whose ages varied between 18 and 25 years and applied to our dermatology outpatient clinic, were evaluated. A questionnaire containing dietary and lifestyle habits for BPA exposure was filled. BPA and BPA glucuronides were analyzed in the LC-MS/MS system in the first-morning urine samples of the patients. Statistical significance was set at p < 0.05.

RESULTS

The median levels of total BPA were significantly higher in the acne group compared with the control group (7.94 (4.69-20.32) vs. 5.62 (1.52-21.05) µg/g creatinine, respectively; p = 0.04)). The acne severity was positively associated with the BPA values (p = 0.00 rs = 0.534). Higher BPA level was noticed in younger acne onset age (p = 0.012 r = -0.349) When the inquiry questions were evaluated, no difference was found between the study groups regarding BPA exposure risk (p > 0.05).

CONCLUSION

BPA could be a factor in acne development and its severity. Therefore, it may be beneficial to prevent BPA exposure and raise awareness in the adolescence and post-adolescence period, in which industrial products such as junk food and plastic bottled water are used more frequently.

Clinical and biological impact of the exposome on the skin

The skin exposome is defined as the totality of environmental exposures over the life course that can induce or modify various skin conditions. Here, we review the impact on the skin of solar exposure, air pollution, hormones, nutrition and psychological factors. Photoageing, photocarcinogenesis and pigmentary changes are well-established consequences of chronic exposure of the skin to solar radiation. Exposure to traffic-related air pollution contributes to skin ageing. Particulate matter and nitrogen dioxide cause skin pigmentation/lentigines, while ozone causes wrinkles and has an impact on atopic eczema. Human skin is a major target of hormones, and they exhibit a wide range of biological activities on the skin. Hormones decline with advancing age influencing skin ageing. Nutrition has an impact on numerous biochemical processes, including oxidation, inflammation and glycation, which may result in clinical effects, including modification of the course of skin ageing and photoageing. Stress and lack of sleep are known to contribute to a pro-inflammatory state, which, in turn, affects the integrity of extracellular matrix proteins, in particular collagen. Hormone dysregulation, malnutrition and stress may contribute to inflammatory skin disorders, such as atopic dermatitis, psoriasis, acne and rosacea.

From bench to bedside: Biosensing strategies to evaluate endocrine disrupting compounds based on epigenetic events and their potential use in medicine

The relationship between endocrine system disorders and health risks due to chemical environmental compounds has become a growing concern in recent years. Involuntary exposure to endocrine disruptors (EDCs) is associated with the worldwide increase of diseases such as cancer, obesity, diabetes, and neurocortical disorders. EDCs are compounds that target the nuclear hormonereceptors (NHR) leading to epigenetic changes. Consequently, the use of biosensing strategies based on epigenetic events have a great potential to provide outstanding information about the exposition of EDCs and their evaluation in human health. This review addresses the novel trends in biosensing EDCs evaluation based on DNA methylation assays associated with different human diseases.

Chloracne and Hyperpigmentation Caused by Exposure to Hazardous Aryl Hydrocarbon Receptor Ligands

Dioxins and dioxin-like compounds are environmental pollutants that are hazardous to human skin. They can be present in contaminated soil, water, and air particles (such as ambient PM_2.5). Exposure to a high concentration of dioxins induces chloracne and hyperpigmentation. These chemicals exert their toxic effects by activating the aryl hydrocarbon receptor (AHR) which is abundantly expressed in skin cells, such as keratinocytes, sebocytes, and melanocytes. Ligation of AHR by dioxins induces exaggerated acceleration of epidermal terminal differentiation (keratinization) and converts sebocytes toward keratinocyte differentiation, which results in chloracne formation. AHR activation potently upregulates melanogenesis in melanocytes by upregulating the expression of melanogenic enzymes, which results in hyperpigmentation. Because AHR-mediated oxidative stress contributes to these hazardous effects, antioxidative agents may be potentially therapeutic for chloracne and hyperpigmentation.

Salidroside prevents skin carcinogenesis induced by DMBA/TPA in a mouse model through suppression of inflammation and promotion of apoptosis

Salidroside (SR) is a main component of Rhodiola rosea L. and exhibits a variety of pharmacologic properties. The present study was carried out to explore the potential effect of SR against skin cancer induced by 7,12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanoylphorbol-13‑acetate (TPA) in female Institute for Cancer Research (ICR) mice and to reveal the underlying molecular targets regulated by SR. The mice were randomly divided into 4 groups: control, DMBA/TPA, DMBA/TPA+SR (20 mg/kg) and DMBA/TPA+SR (40 mg/kg). SR was administered to mice five times a week after DMBA treatments. In our study, we found that SR dose-dependently ameliorated skin cancer incidence and the multiplicity in the animal models by reducing the release of inflammation-related cytokines, including tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-18 (IL-18), interleukin-6 (IL-6), cyclooxygenase 2 (COX2) and transforming growth factor β-1 (TGF-β1). Suppression of the nuclear factor (NF)-κB signaling pathway by SR was effective to prevent skin carcinogenesis. Furthermore, TUNEL analysis indicated that compared to the DMBA/TPA group, enhanced apoptosis was observed in the DMBA/TPA+SR group. In addition, p53 expression levels were increased by SR in the DMBA/TPA-induced mice. Therefore, SR was effective for inducing apoptosis during skin cancer progression triggered by DMBA/TPA. Consistently, p21, p53 upregulated modulator of apoptosis (PUMA), Bax and caspase-3 were highly induced by SR to enhance the apoptotic response for preventing skin cancer. Moreover, in vitro, we found that SR dramatically reduced the inflammatory response, while enhancing the aoptotic response by blocking NF-κB and activating caspase-3 pathways, respectively. In addition, flow cytometric analysis further confirmed the induction of apoptosis by SR in DMBA-treated cells in vitro. Taken together, the in vivo and in vitro studies illustrated that SR might be a promising compound to reduce skin cancer risk.

Particulate matter 2.5 regulates lipid synthesis and inflammatory cytokine production in human SZ95 sebocytes

A large body of evidence indicates that particulate matter (PM)2.5 is associated with various negative effects on human health. However, the impact and molecular mechanism of PM2.5 on the skin have not been elucidated. Therefore, the present study aimed to investigate the effects of two types of PM2.5 [water-soluble extracts (W-PM2.5) and non-water-soluble extracts (NW-PM2.5)] on cell proliferation, cell cycle progression, lipid synthesis, and inflammatory cytokine production of human SZ95 sebocytes. The results demonstrated that NW-PM2.5 and W-PM2.5 exposure dose-dependently inhibited SZ95 sebocyte proliferation by inducing G1 cell arrest. Furthermore, NW-PM2.5 and W-PM2.5 significantly reduced sebaceous lipid synthesis and markedly promoted the production of inflammatory cytokines, including interleukin-1α (IL-1α), IL-6 and IL-8 in SZ95 sebocytes. Additionally, the expression of aryl hydrocarbon (Ah) receptor (AhR), AhR nuclear translocator protein (ARNT), as well as cytochrome P450 1A1 were significantly increased following PM2.5 exposure. Thus, these findings indicate that PM2.5 exerts inhibitory effects on cell proliferation and lipid synthesis, and stimulatory effects on inflammatory cytokine production and AhR signaling activation in human SZ95 sebocytes.