Associations between the Level of Trace Elements and Minerals and Folate in Maternal Serum and Amniotic Fluid and Congenital Abnormalities

Correlation between essential and toxic elements in maternal blood during early pregnancy and atrial septal defects/ventricular septal defects/patent ductus arteriosus in offspring

BACKGROUND

Congenital heart defects (CHDs) are the most common congenital malformation in the world. Recent studies have found that essential and toxic trace element levels may play a crucial role in the risk of neonatal malformation. However, the relationships between element levels in early pregnancy and CHD risk among humans remain unclear. This study investigates the association between maternal essential element (copper [Cu], zinc [Zn], calcium [Ca], manganese [Mg] and iron [Fe]) and toxic element (lead [Pb] and cadmium [Cd]) levels during early pregnancy and CHDs.

METHODS

A hospital-based case-control study was conducted, including 181 cases and 218 controls. Eligible participants underwent antenatal examination during gestational weeks 11-14 and trace element levels were detected by the atomic absorption method. Multi-variable logistic regression was used to examine the associations between the level of maternal trace elements and CHD risks.

RESULTS

Higher levels of Ca in early pregnancy were associated with lower risk of ASD/VSD risks. Moreover, higher Fe, Pb, and Cd levels in the first trimester were associated with higher risks of all CHD and the subtypes risks, and the tests for trend were significant (all p < .05). The restricted cubic spline analysis showed that there was a nonlinear inverted u-shaped dose-response relationship between levels of Zn, Pb, and Cd in the first trimester and risk of CHDs (non-linearity test p < .05).

CONCLUSIONS

A moderate increase in Zn and Ca levels and a decrease in Pb and Cd levels during early pregnancy are needed to reduce the incidence of CHDs in the Chinese population.

Association between aluminum and iron exposure in maternal blood and umbilical cord blood and congenital heart defects in children

Background

Congenital heart disease (CHDs) is the major cause of mortality from birth defects, affecting up to 1% of live births worldwide. However, the relationship between aluminum (Al) and iron (Fe) levels and the risk of CHDs has yielded inconsistent results.

Methods

We conducted a pair-matched case-control study that included 97 CHDs and 194 non-CHDs to investigate the association and interaction between Al/Fe exposure and the risk of CHDs in a birth cohort study in Lanzhou, China.

Results

Higher concentrations of cord blood Al were associated with a greater risk of total CHDs (aOR = 2.826, 95% CI [1.009-7.266]) and isolated CHDs (aOR = 10.713, 95% CI [1.017-112.851]) compared to the lowest Al level. Both in maternal blood and cord blood, a significant dose-effect was observed between Al level and total CHDs (Ptrend < 0.05), but a similar pattern was not observed for Fe. High Al in addition to high Fe appeared to elicit a stronger association with CHDs than both lowest tertile of Al and Fe level in umbilical cord blood, particularly for multiple CHDs, septal defects and patent ductus arteriosus.

Conclusions

Our study suggests that exposure to Al during pregnancy (≥2,408 μg/L) is significantly associated with an increased risk of CHDs in offspring, especially septal defects, and that high levels of Al and Fe are strongly correlated with fetal heart development. Further research is needed to understand the underlying mechanisms.

Trace element concentrations in blood samples from dairy cows with uterine torsion and their neonatal calves

Background and Aim

Mineral deficiencies can lead to dystocia and abnormalities in neonates. Stillbirth of neonatal calves in dairy cows due to dystocia has become an economic problem. Uterine torsion (UT) is a common form of dystocia observed in dairy cows. However, to the best of our knowledge, there have been no reports on the characteristics of serum trace element concentrations in dairy cows with UT. This study aimed to comprehensively measure serum trace element concentrations in dairy cows with UT and dystocia.

Materials and Methods

Dairy cows with (n = 15) and without (n = 27) UT and neonates (n = 9 and n = 26, respectively) were included in this study. Blood samples (10 mL) were collected, and serum trace element concentrations were evaluated using inductively coupled plasma mass spectrophotometry.

Results

The mortality rate at birth was significantly higher in calves delivered by cows with UT than those delivered by cows without UT. The odds ratio for mortality rate at birth in dairy cows with UT was 7.85. Serum zinc (Zn) levels were significantly lower in cows with UT than in cows without UT (p = 0.01). The copper: Zn ratio was significantly higher in cows with UT than in cows without torsion (p = 0.05). In contrast, serum Cobalt (Co) concentrations were significantly higher in neonates from cows with UT than in neonates from cows without UT (p = 0.01).

Conclusion

Uterine torsion is associated with a high mortality rate at birth and considerable economic losses. Cows with UT had low serum Zn levels, and neonates born to these cows had high serum Co levels.

Associations Between the Lead Level in Maternal Blood and Umbilical Cord Blood and Congenital Heart Diseases in Offspring

The incidence of congenital heart diseases (CHDs) shows an increasing trend and results in large health burdens in China. However, there have been inconsistent results of the relationship between lead (Pb) level and risk of CHDs. We performed a pair-matched case-control study and included 97 cases and 194 controls to investigate the association between pregnancy Pb exposure and the risk of CHDs in a birth cohort study conducted in Lanzhou, China. The results showed that compared to the lowest Pb tertile, both highest tertile levels of maternal blood and umbilical cord blood Pb were associated with an increased risk of CHDs. The similar significant results were found in cases with isolated CHDs. Compared to both lowest tertiles of Pb level in maternal blood and umbilical cord blood, the highest tertile was associated with an increased risk of CHDs, especially for isolated CHDs. Overall, our study suggests a significant association between pregnancy Pb exposure and risk of CHDs, especially for isolated CHDs. Future studies are needed to elucidate the underlying mechanism.

In utero deposition of trace elements and metals in tissues

INTRODUCTION

All animals, including humans, are exposed to heavy metals which are known to accumulate in different tissues, especially in bone. During pregnancy, the maternal bone turnover is increased and the metals in the mother's body can be mobilized into the bloodstream. Heavy metals in maternal blood are known to pass through the placenta to the fetal blood and finally, deposited to bone tissue. However, there are no studies on the concentration of metals in the fetal solid tissues and until now, the rate of metal transfer from mother to fetus is not exactly known.

MATERIALS AND METHODS

Samples of the blood, liver, placenta, and three different bones were collected from 17 pregnant ewes and their 27 fetuses. The animals had no known exposure to heavy metals. The concentrations of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Sn, Sr, Te, Ti, Tl, V, and Zn were analyzed using ICP-MS.

RESULTS AND DISCUSSION

The concentration of Sb, Sn, Te, and Tl were under the detection limit in all the samples. The other metals were found in all maternal and fetal tissues, suggesting that all detectable metals cross the placenta. Blood concentrations were low compared to solid tissue concentrations. The concentrations of essential elements varied between maternal and fetal tissues, which could be explained by biological differences. The differences in concentrations of non-essential elements between the ewe and fetuses were smaller. The most significant differences were between maternal and fetal concentrations of Ba and Sr, which is at least partly explained by the mineralization degree of the bone.

CONCLUSION

Heavy metals accumulate in fetal solid tissues in sheep that are not directly exposed to heavy metals. Because of the differences in anatomy between human and sheep placenta, the accumulation in the tissue of human fetuses should be extrapolated cautiously. However, there might be some clinical relevance for fertile aged women who are exposed to heavy metals, such as women who work in the metal industry or who have undergone joint replacement surgery.

Relationship between maternal heavy metal exposure and congenital heart defects: a systematic review and meta-analysis

Congenital heart defects (CHDs) are one of the major causes of death in infants and young children, and heavy metal exposure during pregnancy is one of the possible risk factors. However, the effect of heavy metal exposure on CHDs is still controversial. We searched English (PubMed, Web of Science) and Chinese (CNKI and WanFang database) databases for relevant articles. The summarized effect sizes and 95% confidence intervals (CIs) were calculated by pooling estimates using the random-effects model. Egger's test was used to estimate publication bias. Heterogeneity among studies was indicated by p-values and I². Finally, we conducted subgroup analyses to elucidate the causes of heterogeneity. Thirteen studies were included in this meta-analysis. A positive association between maternal exposure to heavy metals and CHDs was found. Pooling odds ratios (ORs) for arsenic, cadmium, mercury, and lead were 2.12, 1.30, 1.22, and 2.30, respectively for total CHDs. Regarding CHD subtypes, arsenic was associated with an increased risk of septal defects (OR: 1.82), barium with left ventricular outflow tract obstruction (LVOTO) (OR: 1.15) and septal defects (OR: 1.21), and lead with conotruncal defects (OR: 2.34) and LVOTO (OR: 1.93). A heterogeneous relationship was found between studies using different methods of measurement, which were mainly due to differences in actual exposure levels to heavy metals. This meta-analysis suggests significant associations between arsenic, cadmium, mercury, and lead exposure during pregnancy and an increased risk of specific CHDs in offspring. These findings underscore the importance of heavy metal exposure during pregnancy in the risk of CHDs in offspring.

Iron and Folic Acid Supplementation Affects Mineral Status in Female Rats with a Deficiency of These Micronutrients

Supplementation with iron and folic acid is widely recommended in women of childbearing age and during pregnancy; however, the effect of such supplementation on mineral status is not well-known. The aim of this study was to determine the effects of oral iron and folic acid, administered together and separately, on copper, zinc, calcium, and magnesium concentrations in the tissues of rats with a deficiency of both these micronutrients. The experiment was performed on 8-week-old female Wistar rats. In the first stage of the experiment, the animals were randomly assigned to a control group of rats fed the standard diet (AIN-93 M), and to a study group of rats fed a diet deficient in iron and folate. The study group was then randomly divided to four groups: group D was fed a deficit diet, group FE was fed a deficit diet with iron gluconate, the FOL group was fed a deficit diet with folate acid, and the FEFOL group was fed a deficit diet with iron gluconate and folate acid. After 2, 10, and 21 days of the intervention, ten animals from each group were killed. Mineral concentrations were assayed in the liver, spleen, pancreas, heart, and kidneys using atomic absorption spectrometry. Statistical analysis was performed using Statistica 12.0 with the ANOVA test (p < 0.05). It was found that separate supplementation with iron and folic acid significantly decreased copper concentrations in tissues. The deficit in iron and folic acid decreased, and their simultaneous supplementation increased calcium content in the organs. Separate and simultaneous supplementation decreased magnesium status in deficient rats. In conclusion, iron and folic acid, supplemented separately or simultaneously, affect the copper, calcium, and magnesium level in tissues.

Analyses of maternal plasma cadmium, lead, and vanadium levels in the diagnosis and severity of late-onset preeclampsia: a prospective and comparative study

INTRODUCTION

Cadmium, lead, and vanadium, important pollutants produced from anthropogenic activities, have been suggested to be embryotoxic and fetotoxic in many studies. However, the causes of preeclampsia are little known and heavy metals merit further investigation. We tested whether late-onset preeclampsia (L-PrE) was associated with exposure to these metals.

METHODS

This study was designed to determine maternal plasma cadmium, lead, and vanadium concentrations in women with L-PrE (n = 46) compared with those of normotensive women (n = 46). The concentrations of the metals were measured using inductively coupled plasma-mass spectrometry and compared.

RESULTS

The groups were matched for maternal age, gestational age, and gravidity (p ≥ 0.05). Vanadium concentrations differed between the groups (p = 0.007). In contrast, there were no significant differences in the concentrations of cadmium and lead between the groups (p ≥ 0.05). There was no difference between the concentrations of the metals in patients with mild (n = 23) and severe (n = 23) preeclampsia in L-PrE (p ≥ 0.05). A significant discriminative role of vanadium for the presence of L-PrE, with a cutoff value of 1.84 µg/L, was found in ROC curve analysis. When the patients with and without small-for-gestational-age infants were compared (n = 12, and n = 80, respectively), it was determined that there were no differences between cadmium, lead, and vanadium concentrations (p ≥ 0.05).

CONCLUSION

Lower levels of vanadium might be associated with the development of L-PrE. Our findings require further investigation in other populations.