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Frontiers in Cell and Developmental... 2023Neural rosettes develop from the self-organization of differentiating human pluripotent stem cells. This process mimics the emergence of the embryonic central nervous... (Review)
Review
Neural rosettes develop from the self-organization of differentiating human pluripotent stem cells. This process mimics the emergence of the embryonic central nervous system primordium, i.e., the neural tube, whose formation is under close investigation as errors during such process result in severe diseases like spina bifida and anencephaly. While neural tube formation is recognized as an example of self-organization, we still do not understand the fundamental mechanisms guiding the process. Here, we discuss the different theoretical frameworks that have been proposed to explain self-organization in morphogenesis. We show that an explanation based exclusively on stem cell differentiation cannot describe the emergence of spatial organization, and an explanation based on patterning models cannot explain how different groups of cells can collectively migrate and produce the mechanical transformations required to generate the neural tube. We conclude that neural rosette development is a relevant experimental 2D model of morphogenesis because it is a multi-scale self-organization process that involves both cell differentiation and tissue development. Ultimately, to understand rosette formation, we first need to fully understand the complex interplay between growth, migration, cytoarchitecture organization, and cell type evolution.
PubMed: 37635866
DOI: 10.3389/fcell.2023.1134091 -
Environmental Health Perspectives Aug 2023Neural tube defects (NTDs) affect pregnancies worldwide annually. Few nongenetic factors, other than folate deficiency, have been identified that may provide... (Review)
Review
BACKGROUND
Neural tube defects (NTDs) affect pregnancies worldwide annually. Few nongenetic factors, other than folate deficiency, have been identified that may provide intervenable solutions to reduce the burden of NTDs. Prenatal exposure to toxic metals [arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn) and lead (Pb)] may increase the risk of NTDs. Although a growing epidemiologic literature has examined associations, to our knowledge no systematic review has been conducted to date.
OBJECTIVE
Through adaptation of the Navigation Guide systematic review methodology, we aimed to answer the question "does exposure to As, Cd, Hg, Mn, or Pb during gestation increase the risk of NTDs?" and to assess challenges to evaluating this question given the current evidence.
METHODS
We selected available evidence on prenatal As, Cd, Hg, Mn, or Pb exposure and risk of specific NTDs (e.g., spina bifida, anencephaly) or all NTDs via a comprehensive search across MEDLINE, Embase, Web of Science, and TOXLINE databases and applied inclusion/exclusion criteria. We rated the quality and strength of the evidence for each metal. We applied a customized risk of bias protocol and evaluated the sufficiency of evidence of an effect of each metal on NTDs.
RESULTS
We identified 30 studies that met our criteria. Risk of bias for confounding and selection was high in most studies, but low for missing data. We determined that, although the evidence was limited, the literature supported an association between prenatal exposure to Hg or Mn and increased risk of NTDs. For the remaining metals, the evidence was inadequate to establish or rule out an effect.
CONCLUSION
The role of gestational As, Cd, or Pb exposure in the etiology of NTDs remains unclear and warrants further investigation in high-quality studies, with a particular focus on controlling confounding, mitigating selection bias, and improving exposure assessment. https://doi.org/10.1289/EHP11872.
Topics: Female; Pregnancy; Humans; Cadmium; Lead; Prenatal Exposure Delayed Effects; Neural Tube Defects; Mercury; Manganese; Arsenic
PubMed: 37647124
DOI: 10.1289/EHP11872 -
Annals of Medicine and Surgery (2012) Nov 2023Acalvaria is a rare congenital malformation in which the flat bones of the cranial vault, dura mater, and associated muscles are absent while the central nervous system...
INTRODUCTION AND IMPORTANCE
Acalvaria is a rare congenital malformation in which the flat bones of the cranial vault, dura mater, and associated muscles are absent while the central nervous system usually remains unaffected. It is an extremely rare congenital anomaly with only a handful of cases being reported in literature.
CASE PRESENTATION
The authors report a case of a 2-month-old male infant with acalvaria who was delivered at home and brought to our centre with the complaint of an abnormally soft skull. He was evaluated in a primary centre in rural Nepal. Parietal bones were missing bilaterally but no other abnormalities were found during the physical examination and investigations. Major differential diagnoses like anencephaly, cephalocele, osteogenesis imperfecta type II, and hypophosphatasia were ruled out with the help of history, physical examination, and available investigations and the case was diagnosed as acalvaria.
CLINICAL DISCUSSION
Acalvaria is a post-neurulation defect which is associated with anomalies of various organ systems. Radiological diagnosis, with supportive laboratory investigations, is the most reliable method of antenatal diagnosis.
CONCLUSION
Acalvaria is known to have a dismal prognosis and all the living cases with long-term follow-up are mentally retarded and physically disabled. Early and reliable antenatal diagnosis can reduce the economic, physical, and psychological burden associated with this fatal disease, especially in low-income countries.
PubMed: 37915700
DOI: 10.1097/MS9.0000000000001339 -
BMJ Open Nov 2023This study aims to estimate the prevalence of neural tube defects (NTDs) and to identify potential risk factors in the Ethiopian context. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
This study aims to estimate the prevalence of neural tube defects (NTDs) and to identify potential risk factors in the Ethiopian context.
STUDY DESIGN
Systematic review and meta-analysis.
STUDY PARTICIPANTS
A total of 611 064 participants were included in the review obtained from 42 studies.
METHODS
PubMed (Medline), Embase and Cochrane Library databases in combination with other potential sources of literature were systematically searched, whereby studies conducted between January 2010 and December 2022 were targeted in the review process. All observational studies were included and heterogeneity between studies was verified using Cochrane Q test statistics and I test statistics. Small study effects were checked using Egger's statistical test at a 5% significance level.
RESULT
The pooled prevalence of all NTDs per 10 000 births in Ethiopia was 71.48 (95% CI 57.80 to 86.58). The between-study heterogeneity was high (I= 97.49%, p<0.0001). Birth prevalence of spina bifida (33.99 per 10 000) was higher than anencephaly (23.70 per 10 000), and encephalocele (4.22 per 10 000). Unbooked antenatal care (AOR 2.26, 95% CI (1.30 to 3.94)), preconception intake of folic acid (AOR 0.41, 95% CI (0.26 to 0.66)), having chronic medical illness (AOR 2.06, 95% CI (1.42 to 2.99)), drinking alcohol (AOR 2.70, 95% CI (1.89 to 3.85)), smoking cigarette (AOR 2.49, 95% CI (1.51 to 4.11)), chewing khat (AOR 3.30, 95% CI (1.88 to 5.80)), exposure to pesticides (AOR 3.87, 95% CI (2.63 to 5.71)), maternal age ≥35 (AOR 1.90, 95% CI (1.13 to 3.25)), maternal low educational status (AOR 1.60, 95% CI (1.13 to 2.24)), residing in urban areas (AOR 0.75, 95% CI (0.58 to 0.97))and family history of NTDs (AOR 2.51, 95% CI (1.36 to 4.62)) were associated with NTD cases.
CONCLUSION
The prevalence of NTDs in Ethiopia is seven times as high as in other Western countries where prevention measures are put in place. Heredity, maternal and environmental factors are associated with a high prevalence of NTDs. Mandatory fortification of staple food with folic acid should be taken as a priority intervention to curb the burden of NTDs. To smoothen and overlook the pace of implementation of mass fortification, screening, and monitoring surveillance systems should be in place along with awareness-raising measures.
PROSPERO REGISTRATION NUMBER
CRD42023413490.
Topics: Female; Pregnancy; Humans; Prevalence; Ethiopia; Neural Tube Defects; Folic Acid; Risk Factors; Food, Fortified
PubMed: 37940152
DOI: 10.1136/bmjopen-2023-077685 -
Birth Defects Research Jan 2024We provide updated crude and adjusted prevalence estimates of major birth defects in the United States for the period 2016-2020.
BACKGROUND
We provide updated crude and adjusted prevalence estimates of major birth defects in the United States for the period 2016-2020.
METHODS
Data were collected from 13 US population-based surveillance programs that used active or a combination of active and passive case ascertainment methods to collect all birth outcomes. These data were used to calculate pooled prevalence estimates and national prevalence estimates adjusted for maternal race/ethnicity for all conditions, and maternal age for trisomies and gastroschisis. Prevalence was compared to previously published national estimates from 1999 to 2014.
RESULTS
Adjusted national prevalence estimates per 10,000 live births ranged from 0.63 for common truncus to 18.65 for clubfoot. Temporal changes were observed for several birth defects, including increases in the prevalence of atrioventricular septal defect, tetralogy of Fallot, omphalocele, trisomy 18, and trisomy 21 (Down syndrome) and decreases in the prevalence of anencephaly, common truncus, transposition of the great arteries, and cleft lip with and without cleft palate.
CONCLUSION
This study provides updated national estimates of selected major birth defects in the United States. These data can be used for continued temporal monitoring of birth defects prevalence. Increases and decreases in prevalence since 1999 observed in this study warrant further investigation.
Topics: Humans; Down Syndrome; Gastroschisis; Heart Defects, Congenital; Maternal Age; Transposition of Great Vessels; United States; Female
PubMed: 38277408
DOI: 10.1002/bdr2.2301