High concentrations of aluminum in maternal serum and placental tissue are associated with increased risk for fetal neural tube defects

Effects of trimester-specific urinary aluminum concentrations on ultrasound measures of fetal growth and size at birth: A longitudinal cohort study in Chinese women

OBJECTIVE

Aluminum (Al) has been proposed as a potential factor influencing fetal growth. However, the existing study findings are inconsistent and there is a lack of population-based epidemiological studies. Our study aimed to evaluate the trimester-specific correlations of Al exposure with fetal development characteristics.

METHODS

Between 2013 and 2016, 3599 women from Wuhan, China were enrolled in the prospective cohort study. The concentrations of Al were quantified in urine samples obtained from pregnant women during the 1st, 2nd and 3rd trimesters by inductively coupled plasma mass spectrometry. The study used linear regressions with generalized estimating equation to determine the connections between specific gravity-adjusted urinary Al concentrations in each trimester and fetal growth parameters and birth size indicators.

RESULTS

Trimester-specific Al exposure throughout pregnancy was found to have a negative impact on fetal growth and birth parameters. Besides, statistically significant interactions were detected between biparietal diameter (BPD) (Pinteraction = 0.007), head circumference (Pinteraction = 0.026) at 16 weeks' gestation in the first trimester, BPD (Pinteraction = 0.015) at 24 weeks' gestation in the second trimester, BPD (Pinteraction = 0.014) at 31 weeks' gestation in the second trimester and BPD (Pinteraction = 0.035) at 37 weeks' gestation in the third trimester and fetal sex, and the strength of the association between the level of Al exposure and BPD was significantly stronger in female fetuses than in male fetuses. Furthermore, we observed three distinct trajectories of trimester-specific Al concentrations during pregnancy. Compared to participants with low-stable group of Al concentrations trajectory, high-stable group was associated with more decrease level of fetal growth parameters and birth size indicators.

CONCLUSION

Our study results reveal that Al might have harmful effects on fetal growth and birth size indicators, especially in female fetuses. Further study is required to examine our findings in other populations.

Birth prevalence and risk factors of neural tube defects in Ethiopia: a systematic review and 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 I2 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 (I2= 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.

Impact of prenatal exposure to metallic elements on neural tube defects: Insights from human investigations

Metallic elements play a pivotal role in maternal and fetal health. Metals can cross the placental barrier and be absorbed by fetuses, where they may affect closure of the neural tube during embryonic development. Neural tube defects (NTDs), which result from aberrant closure of the neural tube three to four weeks post-conception, have a multifactorial and complex etiology that combines genetic variants and environmental exposure. Recent advances in population-level association studies have investigated the link between maternal environmental exposure and NTDs, particularly the influence of metals on the incidence of NTDs. Herein, we present a broad and qualitative review of current literature on the association between maternal and prenatal metal exposure via the maternal peripheral blood, amniotic fluid, placenta, umbilical cord, and maternal hair, and the risk of developing NTDs. Specifically, we identify the various aggravating or attenuating effects of metallic exposure on the risk of NTD formation. This review provides novel insights into the association between environmental metals and NTDs and has important applications for NTD prevention and mitigating environmental exposure to metals.

Fabrication of a luminescent chemosensor for selective detection of Al3+ used as an adjuvant in pharmaceutical drugs

A new fluorescent chemosensor (NAN), fabricated by integrating 2-hydroxy naphthaldehyde and 1,8-naphthalic anhydride, shows high affinity for aluminium over other bio-relevant metal ions. The probe solution rapidly switched from non-fluorescent to bright blue fluorescence upon the addition of Al³⁺ under a UV-lamp, possessing a remarkably low detection limit of 33 nM. The interaction mechanism between the metal ion and NAN has been well established by a number of techniques such as absorbance, fluorescence, and ¹H NMR titration and verified by detailed theoretical calculations as well. To show the practical efficacy of our synthesized probe NAN we have employed it to recognize Al³⁺ only by using a simple paper strip and estimate the concentration of Al³⁺ ions in various pharmaceutical drugs and supplements as they are some of the major sources of aluminium accumulation in the human body resulting in various neurodegenerative disorders, especially Alzheimer's disease.

An Evaluation of Exposure to 18 Toxic and/or Essential Trace Elements Exposure in Maternal and Cord Plasma during Pregnancy at Advanced Maternal Age

Pregnant women of advanced maternal age (AMA) are vulnerable to exposure to the surrounding environment. Assessment of trace elements in pregnant women living in specific areas is important for biomonitoring. However, exposure levels and variation patterns during pregnancy remains controversial and attracts extensive public concern. Therefore, we aimed to evaluate exposure of 18 toxic and/or essential trace elements in maternal plasma and in paired cord plasma during pregnancy at AMA. A total of 48 pregnant women of AMA were recruited in Peking University Third Hospital from 2018 to 2021. Eighteen elements found in maternal plasma during the 1st, 2nd, or 3rd trimester of pregnancy and paired cord plasma were measured by 7700x ICP-MS (Agilent Technologies, Palo Alto, CA, USA) and Elan DRC type II ICP-MS (The Perkin-Elmer Corporation, Waltham, MA USA). Concentrations of Pb, Se, Fe, Zn, and Mo all decreased during pregnancy, while Cu increased. Interestingly, concentrations of Rb decreased initially but then increased. Elements as Al, Co, Se, Cu, and Ni showed significantly lower levels in cord than in maternal plasma, while elements as Sr, Fe, Rb, Mn and Zn displayed significantly higher levels in cord than in maternal plasma. Moreover, positively- interacted clusters were found in Ni-Co-Cu-Al-Rb-Zn and Zn-Mn-Al-Pb in maternal blood. Similar positively-interacted clusters were found in Zn-Ni-Co, Zn-Ni-Fe, Mn-Al-Pb, Fe-Pb-Mn, Fe-Ni-Cu, and Rb-Cu-Sb-Fe-Mn in cord plasma. Furthermore, correlations between paired maternal and cord blood samples for As, Sr, and Mo were statistically significant, indicating that the fetus burden may reflect maternal exposure to some extent. Admittedly, levels of toxic and essential elements in our cohort study were comparatively lower than those in the scientific literature.