Teratogenicity: a mechanism based short review on common teratogenic agents

EGFR/MAPK signaling pathway acts as a potential therapeutic target for sulforaphane-rescued heart tube malformation induced by various concentrations of PhIP exposure

BACKGROUND

2-Amino-1-methyl-6-phenylimidazo [4,5-b] pyrimidine (PhIP) is a known carcinogen generated mainly from cooking meat and environmental pollutants. It is worth exploring the potential of natural small-molecule drugs to protect against adverse effects on embryonic development.

PURPOSE

In this study, we investigated the potential toxicological effects of PhIP on embryonic heart tube formation and the effect of Sulforaphane (SFN) administration on the anti-toxicological effects of PhIP on embryonic cardiogenesis.

STUDY DESIGN AND METHODS

First, the chicken embryo model was used to investigate the different phenotypes of embryonic heart tubes induced by various concentrations of PhIP exposure. We also proved that SFN rescues PhIP-induced embryonic heart tube malformation. Second, immunofluorescence, western blot, Polymerase Chain Reaction (PCR) and flow cytometry experiments were employed to explore the mechanisms by which SFN protects cardiac cells from oxidative damage in the presence of PhIP. We used RNA-seq analysis, molecular docking, in situ hybridization, cellular thermal shift assay and solution nuclear magnetic resonance spectroscopy to explore whether SFN protects cardiogenesis through the EGFR/MAPK signaling pathway.

RESULTS

The study showed that PhIP might dose-dependently interfere with the C-looping heart tube (mild) or the fusion of a pair of bilateral endocardial tubes (severe) in chick embryos, while SFN administration prevented cardiac cells from oxidative damage in the presence of high-level PhIP. Furthermore, we found that excessive reactive oxygen species (ROS) production and subsequent apoptosis were not the principal mechanisms by which low-level PhIP induced malformation of heart tubes. This is due to PhIP-disturbed Mitogen-activated protein kinase (MAPK) signaling pathway could be corrected by SFN administration.

CONCLUSIONS

This study provided novel insight that PhIP exposure could increase the risk of abnormalities in early cardiogenesis and that SFN could partially rescue various concentrations of PhIP-induced abnormal heart tube formation by targeting EGFR and mediating EGFR/MAPK signaling pathways.

Human Pluripotent Stem Cell-Based Assays to Predict Developmental Toxicity

Human beings are continuously exposed to various toxic substances throughout their lives, which affect their reproductive health and eventually the offspring they give birth to. Mainly, these toxins damage the heart and neurological development of the newborn, but most recently, they have begun to affect the musculoskeletal system as well. These toxins are usually present in food, pharmaceuticals, cosmetics, or even the polluted air that people breathe; as a result, the prevalence of birth defects is steadily rising. For this reason, it becomes a necessity to deploy a new set of assays to test for such toxins in industries to decrease the occurrence of developmental toxicity. These assays are exceedingly expensive when carried out conventionally using animal models or cells from such sources and have a lower predictive value due to the vast variation between animals and humans. To overcome such major problems, human pluripotent stem cells are now frequently used for these assays. These cells are easily available, are quickly generated from somatic cells (induce pluripotent stem cells), can be of human origin without harming people, and eliminate animal harm, which makes them the top choice of scientists for carrying out any in vitro developmental toxicity assays.This chapter, therefore, provides an overview of several steps that can be used to predict a compound's developmental toxicity by utilizing human pluripotent stem cells. Here, the easiest and most effective procedure has been outlined that can screen many compounds simultaneously.

Teratogenic impacts of Antiepileptic drugs on development, behavior and reproduction in Drosophila melanogaster

Clobazam (CLB) and Vigabatrin (VGB) are the two widely used Antiepileptic drugs, which may have teratogenic potentiality and it has been evaluated in the fruit fly Drosophila melanogaster. These different concentrations of CLB (0.156, 0.25, and 0.312 μg/ml) and VGB (17.6, 22, and 44 μg/ml) were used to evaluate the life-history parameters, developmental, and behavioral abnormalities. The results revealed that life-history parameters (fecundity, fertility, larval and pupal mortality) were significantly affected along with varied developmental duration, and pupal and adult deformities in flies on exposure of CLB and VGB in concentration dependent manner. The present study demonstrated that the prenatal treatment of CLB and VGB has displayed clear teratogenic potentiality with various deformities in the fruit fly. The findings could be correlated with the various abnormalities in human caused by the use of AEDs.

Medication history-wide association studies for pharmacovigilance of pregnant patients

Background

Systematic exclusion of pregnant people from interventional clinical trials has created a public health emergency for millions of patients through a dearth of robust safety data for common drugs.

Methods

We harnessed an enterprise collection of 2.8 M electronic health records (EHRs) from routine care, leveraging data linkages between mothers and their babies to detect drug safety signals in this population at full scale. Our mixed-methods signal detection approach stimulates new hypotheses for post-marketing surveillance agnostically of both drugs and diseases—by identifying 1,054 drugs historically prescribed to pregnant patients; developing a quantitative, medication history-wide association study; and integrating a qualitative evidence synthesis platform using expert clinician review for integration of biomedical specificity—to test the effects of maternal exposure to diverse drugs on the incidence of neurodevelopmental defects in their children.

Results

We replicated known teratogenic risks and existing knowledge on drug structure-related teratogenicity; we also highlight 5 common drug classes for which we believe this work warrants updated assessment of their safety.

Conclusion

Here, we present roots of an agile framework to guide enhanced medication regulations, as well as the ontological and analytical limitations that currently restrict the integration of real-world data into drug safety management during pregnancy. This research is not a replacement for inclusion of pregnant people in prospective clinical studies, but it presents a tractable team science approach to evaluating the utility of EHRs for new regulatory review programs—towards improving the delicate equipoise of accuracy and ethics in assessing drug safety in pregnancy.

A review of toxigenic fungi and mycotoxins in feeds and food commodities in West Africa

Fungal contamination is a threat to food safety in West Africa with implications for food and feed due to their climate, which is characterised by high temperatures and high relative humidity, which are environmental favourable for fast fungal growth and mycotoxin production. This report gives perspective on studies on toxigenic fungi (Aspergillus, Fusarium and Penicillium) and their toxins, mainly aflatoxins, fumonisins and ochratoxins commonly found in some West African countries, including Benin, Burkina Faso, Gambia, Ghana, Ivory Coast, Mali, Nigeria, Senegal, Sierra Leone, and Togo. Only four of these countries have mycotoxins regulations in place for feeds and food products (Ghana, Ivory Coast, Nigeria, and Senegal). Food commodities that are widely consumed and were thoroughly investigated in this region include cereals, peanuts, cassava chips (flakes), cassava flour, chilies, peanuts, locust beans, melon, and yam products. In conclusion, authorities and scientists needed to consider research and approaches to monitor mycotoxins in foods and feeds produced and consumed in West Africa.

A Randomized Controlled Trial on the Efficacy of Integrated Yoga on Pregnancy Outcome

Physiological and biochemical changes occur in pregnancy to nurture the developing fetus. Pregnancy-related experience is unique to every woman. Pregnancy symptoms and complications can range from mild to severe. Many women can lower their risk by performing different therapies. In this context, the present study targets to evaluate the efficacy of integrated yoga consisting of (asanas and pranayama) on pregnancy to reduce the risk of complications. This study is a prospective randomized controlled single-blinded trial with parallel arms: the intervention arm received specific integrated yoga therapy; the control arm received routine standard care from 18 to 22 weeks of gestation until delivery. The incidence of preeclampsia and preterm delivery was lower in the intervention arm. Women in the intervention arm delivered at higher gestational age. Apgar scores and birth weights of neonates were significantly higher in the intervention arm. The findings suggest that yoga is a safe and effective intervention during pregnancy to reduce or prevent pregnancy-related complications. However, further randomized controlled trials are needed to provide firmer evidence regarding the utility and validity of yoga intervention during pregnancy.

Effects of the aqueous extract of Phyllanthus niruri Linn during pregnancy and lactation on neurobehavioral parameters of rats' offspring

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllanthus niruri L. (Phyllanthaceae) is a plant used in traditional medicine, mainly to treat kidney stones. However, the effects of maternal exposure to P. niruri remain poorly explored.

AIM OF THE STUDY

The objective of this study was to investigate the effects of administration of aqueous extract of P. niruri (AEPN) during pregnancy and lactation, in maternal toxicity, reflex maturation, and offspring memory.

MATERIALS AND METHODS

Pregnant rats were divided into three groups (n = 8/group): Control (vehicle), AEPN 75, and AEPN 150 (each respectively treated with P. niruri at a dose of 75 and 150 mg/kg/day). The animals were treated via intragastric gavage during pregnancy and lactation. Weight gain, feed intake, and reproductive performance were analyzed in the mothers. In the offspring, the following tests were performed: Neonatal Reflex Ontogeny, Open Field Habituation Test and the Object Recognition Test in adulthood.

RESULTS

Maternal exposure to AEPN did not influence weight gain, feed intake, or reproductive parameters. In the offspring, anticipation of reflex ontogenesis (time of completion) was observed (p < 0.05). During adulthood, the AEPN groups presented decreases in exploratory activity upon their second exposure to the Open Field Habituation Test (in a dose-dependent manner) (p < 0.05). In the Object Recognition Test, administration of the extract at 75 and 150 mg/kg induced significant dose-dependent improvements in short and long-term memory (p < 0.05).

CONCLUSION

Administration of the AEPN accelerated the reflex maturation in neonates, and improved offspring memory while inducing no maternal or neonatal toxicity.

Gestation at completion of prenatal questionnaires in ALSPAC

Enrolling a cohort in pregnancy can be methodologically difficult in terms of structuring data collection. For example, some exposures of interest may be time-critical while other (often retrospective) data can be collected at any point during pregnancy.  The Avon Longitudinal Study of Parents and Children (ALSPAC) is a prime example of a cohort where certain data were collected at specific time points and others at variable times depending on the gestation at contact.  ALSPAC aimed to enrol as many pregnant women as possible in a geographically defined area with an expected date of delivery between April 1991 and December 1992. The ideal was to enrol women as early in pregnancy as possible, and to collect information, when possible, at two fixed gestational periods (18 and 32 weeks). A variety of methods were used to enrol participants.   Approximately 80% of eligible women resident in the study area were enrolled. Gestation at enrolment ranged from 4-41 (median = 14) weeks of pregnancy. Given this variation in gestation we describe the various decisions that were made in regard to the timing of questionnaires to ensure that appropriate data were obtained from the pregnant women.  45% of women provided data during the first trimester, this is less than ideal but reflects the fact that many women do not acknowledge their pregnancy until the first trimester is safely completed. Data collection from women at specific gestations (18 and 32 weeks) was much more successful (80-85%). Unfortunately, it was difficult to obtain environmental data during the first trimester. Given the time critical nature of exposures during this trimester, researchers must take the gestational age at which environmental data was collected into account. This is particularly important for data collected using the questionnaire named 'Your Environment' (using data known as the A files).