Physical Blocking Neural Tube Closure Affects Radial Intercalation and Neural Crest Midline-directed Migration in Xenopus Dorsal Explants

Neural tube defects （NTDs） are severe congenital malformation diseases, which occur in 1 out of 1000 births in human. In Xenopus, several tissue movements are involved in the neural tube closure process. Immediately after the neural tube fusion, the neural crest cells get monopolar protrusion toward dorsal midline and migrate to form the roof of the neural tube. At the same time, radial intercalation takes place from the ventral neural tube and forces it to be single-layered. Here, we physically block the neural tube closure to test the cell movements and the following patterning in Xenopus laevis explants. The results show that the single-layered neural tube fails to form and the neural crest cells remain at the lateral regions in the explants with NTDs. However, the patterning of the neural tube is not affected as indicated by the normal expression of the preneural genes. These results indicate a requirement of the neural tube fusion for the radial intercalation and the dorsal midline directed neural crest migration, but not for the dorsal-ventral patterning of the neural tube.

Prenatal cadmium exposure impairs neural tube closure via inducing excessive apoptosis in neuroepithelium

Birth defects have become a public health concern.The hazardous environmental factors exposure to embryos could increase the risk of birth defects.Cadmium,a toxic environmental factor,can cross the placental barrier during pregnancy.Pregnant woman may be subjected to cadmium before taking precautionary protective actions.However,the link between birth defects and cadmium remains obscure.Cadmium exposure can induce excessive apoptosis in neuroepithelium during embryonic development progresses.Cadmium exposure activated the p53 via enhancing the adenosine 5‘-monophosphate(AMP)-activated protein kinase(AMPK)and reactive oxygen species'(ROS)level.And cadmium decreases the level of Paired box 3(Pax3)and murine double minute 2(Mdm2),disrupting the process of p53 ubiquitylation.And p53 accumulation induced excessive apoptosis in neuroepithelium during embryonic development progresses.Excessive apoptosis led to the failure of neural tube closure.The study emphasizes that environmental materials may increase the health risk for embryos.Cadmium caused the failure of neural tube closure during early embryotic day.Pregnant women may be exposed by cadmium before taking precautionary protective actions,because of cadmium concentration-containing foods and environmental tobacco smoking.This suggests that prenatal cadmium exposure is a threatening risk factor for birth defects.

Is There a Relationship between COVID-19 Infection and the Occurrence of Anencephaly? Observation of the Maternity of Mohammed the VI University Hospital of Marrakech

Introduction: Morocco has experienced, like the whole world, the COVID-19 pandemic. Until the writing of this article, a subjective observation of the increase in the number of anencephaly has been observed in our facility. And since the teratogenic potential of the SARS Cov 2 virus is not sufficiently documented, we wondered if there would be a relationship between the relatively high number of anencephalic fetuses and COVID-19 infection. Aim: the objective of the study is to look for a possible correlation between the period of conception of these anencephalies and the pandemic. Material and methods: This is a retrospective study (from June 1, 2020 to May 31, 2022 in the Obstetrics Gynecology department, Faculty of Medicine and Pharmacy, CADI AYYAD UNIVERSITY Marrakech Morocco) consisting of the analysis of the number of patients in the target embryonic period (namely the closure of the neural tube: D18 to D30 of embryonic life) compared to the reference curves of the evolution of the SARS Cov2 pandemic. Results: The analysis of the number of patients at the target embryonic phase shows that many of our anencephalons (63%) were conceived during periods of high diffusion of the SARS Cov 2 virus in Morocco. Conclusion: Our study suggests a relationship between the COVID-19 pandemic and the occurrence of anencephaly, we cannot, however, highlight the type of direct or indirect relationship that binds them. Therefore, further studies should be considered to better investigate this relationship.