Effects of Maternal Cigarette Smoking on Trace Element Levels and Steroidogenesis in the Maternal-Placental-Fetal Unit

Characteristics of the transfer of mercury and other trace elements between dam and fetus in a relatively high‑mercury content species, the small Indian mongoose (Urva auropunctata)

We provide the first data regarding the maternal-to-fetal transfer of toxic trace elements (total Hg (THg) and organic Hg (OHg), As, Cd, and Pb) and seven essential minerals (Mg, Cr, Mn, Fe, Cu, Zn, and Se) in the tissues of 29 pairs of small Indian mongoose that were naturally exposed to metals. The fetal mass negatively correlated with the fetal liver O/THg ratio, suggesting that mineralization of Hg from the organic form might occur during fetal growth. The maternal THg and OHg concentrations and THg/Se molar ratios in whole blood and the fetal whole blood (FB)/maternal whole blood (MB) ratios of the OHg and THg concentrations significantly correlated with the fetal hepatic and cerebral Hg levels, indicating that the maternal blood THg and OHg concentrations and the THg/Se and FB/MB ratios may be useful biomarkers of the Hg contents of fetal organs. It was noted that the fetal THg and OHg levels in the liver and whole blood tended to be lower when the dams were exposed to high levels of Hg, suggesting that the placental barrier mechanism may be activated when mongooses are exposed to high levels of Hg. Analysis of the differences in trace element concentrations between maternal blood containing high (>0.044 ppm) and low (<0.044 ppm) Hg exposure showed that fetuses with high maternal Hg exposure may be at higher risk of Pb exposure and Zn depletion than those with dams exposed to low levels of Hg.

Fetus Exposure to Drugs and Chemicals: A Holistic Overview on the Assessment of Their Transport and Metabolism across the Human Placental Barrier

BACKGROUND

The placenta exerts a crucial role in fetus growth and development during gestation, protecting the fetus from maternal drugs and chemical exposure. However, diverse drugs and chemicals (xenobiotics) can penetrate the maternal placental barrier, leading to deleterious, adverse effects concerning fetus health. Moreover, placental enzymes can metabolize drugs and chemicals into more toxic compounds for the fetus. Thus, evaluating the molecular mechanisms through which drugs and chemicals transfer and undergo metabolism across the placental barrier is of vital importance. In this aspect, this comprehensive literature review aims to provide a holistic approach by critically summarizing and scrutinizing the potential molecular processes and mechanisms governing drugs and chemical transfer and metabolism across the placental barrier, which may lead to fetotoxicity effects, as well as analyzing the currently available experimental methodologies used to assess xenobiotics placental transfer and metabolism.

METHODS

A comprehensive and in-depth literature review was conducted in the most accurate scientific databases such as PubMed, Scopus, and Web of Science by using relevant and effective keywords related to xenobiotic placental transfer and metabolism, retrieving 8830 published articles until 5 February 2024. After applying several strict exclusion and inclusion criteria, a final number of 148 relevant published articles were included.

RESULTS

During pregnancy, several drugs and chemicals can be transferred from the mother to the fetus across the placental barrier by either passive diffusion or through placental transporters, resulting in fetus exposure and potential fetotoxicity effects. Some drugs and chemicals also appear to be metabolized across the placental barrier, leading to more toxic products for both the mother and the fetus. At present, there is increasing research development of diverse experimental methodologies to determine the potential molecular processes and mechanisms of drug and chemical placental transfer and metabolism. All the currently available methodologies have specific strengths and limitations, highlighting the strong demand to utilize an efficient combination of them to obtain reliable evidence concerning drug and chemical transfer and metabolism across the placental barrier. To derive the most consistent and safe evidence, in vitro studies, ex vivo perfusion methods, and in vivo animal and human studies can be applied together with the final aim to minimize potential fetotoxicity effects.

CONCLUSIONS

Research is being increasingly carried out to obtain an accurate and safe evaluation of drug and chemical transport and metabolism across the placental barrier, applying a combination of advanced techniques to avoid potential fetotoxic effects. The improvement of the currently available techniques and the development of novel experimental protocols and methodologies are of major importance to protect both the mother and the fetus from xenobiotic exposure, as well as to minimize potential fetotoxicity effects.

Potential pathological mechanisms and pharmacological interventions for cadmium-induced miscarriage

The prevalence of cadmium (Cd) contamination has emerged as a significant global concern. Exposure to Cd during pregnancy is associated with adverse pregnancy outcomes, including miscarriage. However, there is currently a lack of comprehensive summaries on Cd-induced miscarriage. Therefore, it is imperative to further strengthen research into in vivo studies, clinical status, pathological mechanisms, and pharmacological interventions for Cd-induced miscarriage. This study systematically presents the current knowledge on animal models and clinical trials investigating Cd exposure-induced miscarriage. The underlying mechanisms involving oxidative stress, inflammation, endocrine disruption, and placental dysfunction caused by Cd-induced miscarriage are also extensively discussed. Additionally, potential drug interventions such as melatonin, vitamin C, and vitamin E are highlighted for their pharmacological role in mitigating adverse pregnancy outcomes induced by Cd.