Chemical elements and preeclampsia - An overview of current problems, challenges and significance of recent research

An exploratory study on the association of multiple metals in serum with preeclampsia

Background

Individual metal levels are potential risk factors for the development of preeclampsia (PE). However, understanding of relationship between multiple metals and PE remains elusive.

Purpose

The purpose of this study was to explore whether eight metals [zinc (Zn), manganese (Mn), copper (Cu), nickel (Ni), lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg)] in serum had a certain relationship with PE.

Methods

A study was conducted in Dongguan, China. The concentrations of metals in maternal serum were assessed using inductively coupled plasma mass spectrometry (ICP-MS). Data on various factors were collected through a face-to-face interview and hospital electronic medical records. The unconditional logistic regression model, principal component analysis (PCA) and Bayesian Kernel Machine Regression (BKMR) were applied in our study.

Results

The logistic regression model revealed that the elevated levels of Cu, Pb, and Hg were associated with an increased risk of PE. According to PCA, principal component 1 (PC1) was predominated by Hg, Pb, Mn, Ni, Cu, and As, and PC1 was associated with an increased risk of PE, while PC2 was predominated by Cd and Zn. The results of BKMR indicated a significant positive cumulative effect of serum metals on PE risk, with Ni and Cu exhibiting a significant positive effect. Moreover, BKMR results also revealed the nonlinear effects of Ni and Cd.

Conclusion

The investigation suggests a potential positive cumulative impact of serum metals on the occurrence of PE, with a particular emphasis on Cu as a potential risk factor for the onset and exacerbation of PE. These findings offer valuable insights for guiding future studies on this concern.

Variants and Haplotypes of SIRT1 (rs7895833, rs7069102, and rs2273773) are Associated with the Risk of Preeclampsia and Affect the Trace Elements and Antioxidant Enzymes Levels

Preeclampsia is the most common and serious complication of pregnancy. Variants of Sirtuin-1 (SIRT1) as a key player in the regulation of oxidant/antioxidant signaling pathways might be involved in the pathogenesis of preeclampsia. In the present case-control study 300 women with and without preeclampsia were studied for SIRT1 variants (rs7895833, rs7069102, and rs2273773) and haplotypes. Also, the relationship of glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities and Zn, Cu, and Se levels to the polymorphisms were investigated. The SIRT1 rs7895833 A > G, rs7069102 C > G, and the rs2273773 C > T polymorphisms were associated with the risk of preeclampsia. We found the haplotypes G (rs7895833) C (rs7069102) C (rs2273773), GCC, and ACC compared to the AGT decreased the risk of preeclampsia. The risk haplotype of AGT was associated with higher GPx activity compared to the GCC haplotype. A significantly higher level of Cu and lower levels of Zn and Se in patients with preeclampsia compared to controls were detected. Also, a significantly lower SOD and higher GPx activity in preeclamptic patients compared to controls were found. The three risk genotypes of AA (rs7895833), GG (rs7069102), and TT (rs2273773) significantly decreased the Zn level and SOD activity, and the TT genotype (rs2273773) increased the Cu level in all studied women. The presence of rs7069102 polymorphism was associated with enhanced systolic blood pressure. For the first time, we indicated three SIRT1 polymorphisms and the AGT haplotype are risk factors for preeclampsia development. Also, SIRT1 variants and haplotypes affect the levels of antioxidant enzymes and their cofactors, complicating the pregnancy outcome.

Effects of Non-Essential "Toxic" Trace Elements on Pregnancy Outcomes: A Narrative Overview of Recent Literature Syntheses

Adverse pregnancy outcomes and their complications cause increased maternal and neonatal morbidity and mortality and contribute considerably to the global burden of disease. In the last two decades, numerous narrative and systematic reviews have emerged assessing non-essential, potentially harmful, trace element exposure as a potential risk factor. This narrative review summarizes the recent literature covering associations between exposure to cadmium, lead, arsenic, and mercury and pregnancy outcomes and highlights common limitations of existing evidence that may hinder decision-making within public health. Several initial scoping searches informed our review, and we searched PubMed (latest date July 2022) for the literature published within the last five years reporting on cadmium, lead, arsenic, or mercury and pre-eclampsia, preterm birth, or prenatal growth. Pre-eclampsia may be associated with cadmium and strongly associated with lead exposure, and exposure to these metals may increase risk of preterm birth. Many reviews have observed cadmium to be negatively associated with birth weight. Additionally, lead and arsenic exposure may be negatively associated with birth weight, with arsenic exposure also adversely affecting birth length and head circumference. These findings should be interpreted with caution due to the limitations of the reviews summarized in this paper, including high heterogeneity due to different exposure assessment methods, study designs, and timing of sampling. Other common limitations were the low quality of the included studies, differences in confounding variables, the low number of studies, and small sample sizes.

Maternal serum zinc level is associated with risk of preeclampsia: A systematic review and meta-analysis

Background

Preeclampsia (PE) is a multi-organ syndrome that onsets in the second half of pregnancy. It is the second leading cause of maternal death globally. The homeostasis of zinc (Zn) levels is important for feto-maternal health.

Objective

We aimed to collect all studies available to synthesize the evidence regarding the association between maternal Zn levels and the risk of preeclampsia.

Methods

A systematic review and meta-analysis was conducted via searching seven electronic databases [PubMed, Web of Science, Embase, African Journals Online (AJOL), ClinicalTrial.gov, and two Chinese databases: Wanfang and Chinese National Knowledge Infrastructure, CNKI]. Studies reporting maternal serum Zn levels in pregnant women with or without preeclampsia were included. Eligible studies were assessed through Newcastle-Ottawa Scale (NOS) and the meta-analysis was performed via RevMan and Stata. The random-effects method (REM) was used for the meta-analysis with 95% confidence interval (CI). The pooled result was assessed using standard mean difference (SMD). The heterogeneity test was carried out using I 2 statistics, and the publication bias was evaluated using Begg's and Egger's test. Meta-regression and sensitivity analysis was performed via Stata software.

Results

A total of 51 studies were included in the final analysis. 6,947 participants from 23 countries were involved in our study. All studies went through the quality assessment. The pooled results showed that maternal serum Zn levels were lower in preeclamptic women than in healthy pregnant women (SMD: -1.00, 95% CI: -1.29, -0.70). Sub-group analysis revealed that geographical, economic context, and disease severity may further influence serum Zn levels and preeclampsia.

Limitations

There are significant between-study heterogeneity and publication bias among included studies.

Conclusions

A lower level of maternal Zn was associated with increased risks of preeclampsia. The associations were not entirely consistent across countries and regions worldwide.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=337069, Identifier: CRD42022337069.

Association between trace elements and preeclampsia: A retrospective cohort study

BACKGROUND

Preeclampsia is the main cause of maternal and perinatal death. Multiple studies suggest that trace elements were associated with preeclampsia, but the results varied, and less known about early or mid-term pregnancy of trace elements and preeclampsia. We aim to explore the association between mid-term pregnancy trace elements levels and preeclampsia.

METHODS

The retrospective cohort study was consecutively conducted in Foshan Fosun Chancheng Hospital, Guangdong Province, China, from August 1, 2019, to November 30, 2019. Trace elements are derived from the laboratory data system, measured in maternal whole blood during 12-27 (+6) weeks of pregnancy by flame atomic absorption spectrometer method. Preeclampsia diagnosis and covariance were ascertained from the electronic medical records system. We used multivariable logical regression to estimate odds ratios (OR) and 95% CIs.

RESULTS

A total of 2186 participants were included in this study, and 59 (2.70%) women developed preeclampsia. After multivariable adjustment, the OR of Mg levels for preeclampsia was 0.35 (95%CI:0.06,2.20). The fifth quintiles of Mg were associated with 0.29 (95% CI：0.10,0.85) times lower risk of preeclampsia compared with the first quintile, with a dose-response trend (P for trend = 0.056). Per 1 µmol/L increment in Cu was associated with 11% lower risk of preeclampsia (OR=0.89; 95% CI, 0.78,1.02). Compared with the first quintile, the second, third，fourth，fifth quintile of Cu was associated with a odd ratio of 0.12 (95% CI:0.03,0.43),0.67 (95% CI:0.30,1.48),0.33 (95% CI:0.15,0.76) and 0.26 (95% CI:0.10,0.66),respectively. Null associations were observed for Zn, Fe, Ca.

CONCLUSIONS

Higher blood Mg and Cu levels in mid-term pregnancy were associated with lower preeclampsia risk.

A Global Perspective of Correlation Between Maternal Copper Levels and Preeclampsia in the 21st Century: A Systematic Review and Meta-Analysis

Background:

Preeclampsia (PE) is a common multi-system disorder in pregnancy and a major cause of maternal and perinatal morbidity and mortality globally. Copper is a crucial micronutrient for human health.

Methods

A systematic review was performed according to Preferred Reporting Item for Systematic Reviews and Meta-analysis (PRISMA) guidelines to synthesize the best available evidence regarding the correlation between maternal copper levels and PE from women with different geographical and economic backgrounds.

Results

A total of 34 studies containing 2,471 women with PE and 2,888 healthy pregnant controls across 16 countries were included for research. All studies were systematically reviewed and assessed with the Newcastle-Ottawa Scale (NOS), The Agency of Healthcare for Research and Quality (AHRQ) assessment tools according to the study types. Globally, there was no significant difference in maternal serum copper levels between women with PE and control (Mean difference 5.46, 95% CI −9.63, 20.54). Sub-group analysis from geographical and economic perspectives revealed contrasting results. In conclusion, copper is associated with PE, but the levels of copper leading to increased risk of PE varied across regions and economic development.

Conclusions

The deranged maternal copper levels are correlated with risks of PE, but it presents variously across different geographical and economic contexts.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=306536. Identifier: CRD42022306536.

The Role of Inorganics in Preeclampsia Assessed by Multiscale Multimodal Characterization of Placentae

Preeclampsia is one of the most dangerous diseases in pregnancy. Because of the hypertensive nature of preeclampsia, placental calcifications are believed to be a predictor for its occurrence, analogous to their role in cardiovascular diseases. However, the prevalence and the relevance of calcifications for the clinical outcome with respect to preeclampsia remains controversial. In addition, the role of other inorganic components present in the placental tissue in the development of preeclampsia has rarely been investigated. In this work, we therefore characterized inorganic constituents in placental tissue in groups of both normotensive and preeclamptic patients (N = 20 each) using a multi-scale and multi-modal approach. Examinations included elemental analysis (metallomics), sonography, computed tomography (CT), histology, scanning electron microscopy, X-ray fluorescence and energy dispersive X-ray spectroscopy. Our data show that tissue contents of several heavy metals (Al, Cd, Ni, Co, Mn, Pb, and As) were elevated whereas the Rb content was decreased in preeclamptic compared to normotensive placentae. However, the median mineral content (Ca, P, Mg, Na, K) was remarkably comparable between the two groups and CT showed lower calcified volumes and fewer crystalline deposits in preeclamptic placentae. Electron microscopy investigations revealed four distinct types of calcifications, all predominantly composed of calcium, phosphorus and oxygen with variable contents of magnesium in tissues of both maternal and fetal origin in both preeclamptic and normotensive placentae. In conclusion our study suggests that heavy metals, combined with other factors, can be associated with the development of preeclampsia, however, with no obvious correlation between calcifications and preeclampsia.

Circulating trace elements for the prediction of preeclampsia and small for gestational age babies

INTRODUCTION

Poor gestational outcomes due to placental insufficiency can have lifelong consequences for mother and child.

OBJECTIVE

There is a need for better methods of diagnosis, and elemental metabolomics may provide a means to determine the risk of gestational disorders.

METHODS

This study used blood plasma samples collected at 36 weeks' gestation from women who later developed preeclampsia (n = 38), or small-for-gestational age babies (n = 91), along with matched controls (n = 193). Multi-element analysis was conducted by inductively coupled plasma mass spectrometer (ICP-MS), allowing simultaneous measurement of 28 elements.

RESULTS

Women who later developed PE, exhibited significantly increased concentrations of K, Rb and Ba. For SGA pregnancies, there was a significant increase in Cu and a decrease in As concentrations. Despite significant differences in single elements, the elemental profile of groups indicated no clustering of control, PE, or SGA samples. Positive predicative values correctly identified approximately 60% of SGA and 70% of PE samples.

CONCLUSION

This is the first-time elemental metabolomics has been used to predict SGA and PE at 36 weeks. Though significant changes were identified, routine clinical use may be limited but may contribute to a multi marker test. Future analysis should include other biomarkers, metabolic data or clinical measurements made throughout gestation.

Lead Levels in Non-Occupationally Exposed Women with Preeclampsia

There are many controversies regarding the relationship between lead exposure andcomplications in pregnancy. Preeclampsia (PE) is a maternal hypertensive disorder which is one of the main causes of maternal and foetal mortality. The aim of our study was to assess blood lead level (BLL) in Polish women with PE (PE group, n = 66) compared with healthy, non-pregnant women (CNP group, n = 40) and healthy pregnant women (CP group, n = 40). BLL was determined by inductively coupled plasma mass spectrometry (ICP-MS). The systolic blood pressure (SBP), diastolic blood pressure (DBP) and BLL in the CP group were significantly lower than in the PE group (p < 0.001). Logistic regression analyses of BLL showed a significant positive relationship with the presence of PE. Furthermore, both the SBP and DBP values were positively associated with BLL. This study indicates that preeclamptic women tend to present with significantly higher BLL compared to healthy pregnant women. There were no differences in the BLL between the CP and CNP groups.