Associations of Prenatal Exposure to Triclosan and Maternal Thyroid Hormone Levels: A Systematic Review and Meta-Analysis

Redox Status, Estrogen and Progesterone Production by Swine Granulosa Cells Are Impaired by Triclosan

Triclosan is a chlorinated biphenolic with a broad spectrum of antiseptic activities used in cosmetics and hygiene products. Continuous exposure can lead to absorption and bioaccumulation of this substance with harmful health effects. In fact, previous studies have shown that Triclosan acts as an endocrine-disrupting chemical on reproductive organs, with consequent negative effects on reproductive physiology. Therefore, to assess potential adverse impacts on fertility, we tested Triclosan on swine granulosa cells, a model of endocrine reproductive cells. We examined its effects on the main features of granulosa cell functions such as cell growth (BrdU incorporation and ATP production) and steroidogenesis (17-β estradiol and progesterone secretion). Moreover, since oxidant−antioxidant balance plays a pivotal role in follicular function, redox status markers (superoxide, hydrogen peroxide and nitric oxide production, enzymatic and non-enzymatic scavenging activity) were studied. Our results show that Triclosan significantly inhibits cell growth (p < 0.001), steroidogenesis (p < 0.001), superoxide and nitric oxide production (p < 0.001), while it increases (p < 0.05) enzymatic defense systems. Collectively, these data suggest a disruption of the main granulosa cell functions, i.e., proliferation and hormone production, as well as an imbalance in redox status. On these bases, we can speculate that Triclosan would impair granulosa cell functions, thus exerting negative effects on reproductive function. Further studies are needed to explore lower Triclosan concentrations and to unravel its mechanisms of action at gene level.

Triclosan: A Small Molecule with Controversial Roles

Triclosan (TCS), a broad-spectrum antimicrobial agent, has been widely used in personal care products, medical products, plastic cutting boards, and food storage containers. Colgate Total® toothpaste, containing 10 mM TCS, is effective in controlling biofilm formation and maintaining gingival health. Given its broad usage, TCS is present ubiquitously in the environment. Given its strong lipophilicity and accumulation ability in organisms, it is potentially harmful to biohealth. Several reports suggest the toxicity of this compound, which is inserted in the class of endocrine disrupting chemicals (EDCs). In September 2016, TCS was banned by the U.S. Food and Drug Administration (FDA) and the European Union in soap products. Despite these problems, its application in personal care products within certain limits is still allowed. Today, it is still unclear whether TCS is truly toxic to mammals and the adverse effects of continuous, long-term, and low concentration exposure remain unknown. Indeed, some recent reports suggest the use of TCS as a repositioned drug for cancer treatment and cutaneous leishmaniasis. In this scenario it is necessary to investigate the advantages and disadvantages of TCS, to understand whether its use is advisable or not. This review intends to highlight the pros and cons that are associated with the use of TCS in humans.

Prenatal exposure to endocrine-disrupting chemicals and thyroid function in neonates: A systematic review and meta-analysis

Thyroid hormone homeostasis is essential for normal brain development in fetuses and infants. Exposure to endocrine-disrupting chemicals (EDCs) during pregnancy is associated with compromised maternal thyroid homeostasis, and thus may lead to adverse neurodevelopmental outcomes in newborns. However, evidence regarding the association of prenatal EDC exposure and thyroid hormones in newborns is controversial. Therefore, a meta-analysis to elucidate the relationship between maternal exposure to EDCs and neonatal THs was performed. A systematic search of PubMed, EMBASE, and the Cochrane Library (CENTRAL) for relevant published studies that provided quantitative data on the association between prenatal EDC exposure and neonatal thyroid hormones was conducted in August 2021. To calculate the overall estimates, we pooled the adjusted β regression coefficients with 95% confidence intervals (CIs) from each study by the inverse variance method. The pooling results indicated that prenatal EDC exposure had no significant influence on neonatal TSH, TT3, FT3, TT4 or FT4 level in the global assessment. However, in the specific exposure and outcome assessment, we found that prenatal exposure to organochlorine (β coefficient, -0.022; 95% CI, -0.04 to -0.003) and PFAS (β coefficient, -0.017; 95% CI, -0.033 to 0) was negatively associated with neonatal TT4 level. In conclusion, prenatal exposure to organochlorine and PFAS may be associated with lower neonatal TT4 level.