Validation of a Metallomics Analysis of Placenta Tissue by Inductively-Coupled Plasma Mass Spectrometry

The relationship between cadmium exposure and preeclampsia: a systematic review and meta-analysis

Background

Cadmium (Cd) is a heavy metal associated with several human disorders. Preeclampsia is a major cause of maternal mortality worldwide. The association between maternal Cd exposure and preeclampsia remains elusive.

Methods

To better understand this relationship, we conducted a systematic review and meta-analysis of eligible studies from five databases (PubMed, Embase, Web of Science, Scopus, and CNKI) from their inception to September 10, 2022. The quality of these studies was evaluated using the Newcastle-Ottawa quality assessment scale (NOS). We use random-effects models to calculate overall standardized mean differences (SMDs) and 95% confidence intervals (CIs). Sensitivity analyses were performed to assess the robustness of our results. We also evaluated publication bias using Egger's and Begg's tests. Additionally, we conducted meta-regression and sub-group analyses to identify potential sources of heterogeneity between studies.

Results

Our analysis included a total of 17 studies with 10,373 participants. We found a significant association between maternal cadmium exposure and the risk of preeclampsia (SMD 0.27, 95% CI 0.09-0.44, p < 0.01). No significant publication bias was detected in Begg's or Egger's tests. Meta-regression suggested that geographical location, year of publication, cadmium samples, sample size, and measurement methods did not contribute to heterogeneity between studies.

Conclusion

Our findings suggest that maternal blood cadmium levels are associated with an increased risk of preeclampsia. In contrast, the pregnant women's urine or placental levels of cadmium may not suggest preeclamptic risk during pregnancy. Further high-quality clinical studies and animal experiments are needed to understand this association better.

Systematic review registration

PROSPERO, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=361291, identifier: CRD42022361291.

Effects of Quercetin on Acrylamide-Induced Variation of Serum Elements in Rats

Acrylamide (AA) is an organic chemical widely existing in the public diet, especially in foods with high-temperature fried and baked starchy and may have various adverse health effects on organisms. The purpose of this study was to investigate whether quercetin plays a protective role in AA-induced element variation in rats. Rats were randomly divided into the control group, AA-treated group [5 mg/kg body weight (bw)], two dosages of quercetin-treated groups (10 and 50 mg/kg·bw, respectively), and two dosages of quercetin plus AA-treated groups. After a 16-week treatment, the serum samples of rats were collected. Serum elements were analyzed by using inductively coupled plasma mass spectrometry (ICP-MS) combined with multivariate statistical analysis, and antioxidant indices, lipid peroxidation indicator, as well as inflammatory biomarkers, were also detected. The accuracy and precision of the method were verified, and all the validated data are within the satisfactory range. The results showed that the levels of vanadium (V), copper (Cu), zinc (Zn), selenium (Se), cobalt (Co), and magnesium (Mg) in serum were significantly lower (p < 0.01), while serum calcium (Ca) level was significantly higher (p < 0.01) in AA-treated group compared with the control group. When high-dose quercetin was administered to rats combined with AA, a significant recovered effect for the above elements levels was observed compared with the AA-treated group. This study suggests that quercetin (50 mg/kg·bw) exerts a regulatory and protective role in AA-induced variation of serum elements via reducing oxidative stress and inhibiting inflammation.

Determination of lead in human placenta tissue employing slurry sampling and detection by electrothermal atomic absorption spectrometry

A new analytical procedure was developed for the determination of lead in human placental tissue by direct ultrasonic slurry sampling combined with electrothermal atomic absorption spectrometry (SS-ET AAS). Samples of dried and crushed placental tissue were mixed with 10 mL of 0.20% (v/v) HNO₃ and homogenised. The slurries were then transferred to autosampler cups where they were sonicated using an ultrasonic probe prior to injection into a graphite tube with an L'vov platform. The effects of several chemical modifiers, including Mg(NO₃)₂, Pd(NO₃)₂, and NH₄H₂PO₄, were investigated for the stabilisation of lead during thermal pre-treatment. Lead in the slurries was effectively stabilised up to 1200 °C with the Pd(NO₃)₂ modifier providing the best results with complete atomisation at 1900 °C. H₂O₂ was used as a chemical modifier; dilute HNO₃ and HCl were examined as slurry media. The limit of detection and the limit of quantification for lead obtained under optimised conditions were 0.17 μg g^-1 and 0.56 μg g^-1, respectively. The relative standard deviation estimated from twenty replicate measurements of spike solution at a concentration of 50.00 μg L^-1 for lead was 1.51%. The accuracy of the method was confirmed by analysis of the standard reference material BCR 185R "Bovine Liver". The proposed technique is simple, sensitive and environmentally friendly, and the risk of contamination is low. The method was applied to lead determination in real samples of human placental tissue. The 14 samples were taken just after delivery at the Gynaecology and Obstetrics Department of the Faculty Hospital with Outpatients Clinic in Bratislava over the course of 2019.

Aluminum and aluminum oxide nanomaterials uptake after oral exposure - a comparative study

The knowledge about a potential in vivo uptake and subsequent toxicological effects of aluminum (Al), especially in the nanoparticulate form, is still limited. This paper focuses on a three day oral gavage study with three different Al species in Sprague Dawley rats. The Al amount was investigated in major organs in order to determine the oral bioavailability and distribution. Al-containing nanoparticles (NMs composed of Al0 and aluminum oxide (Al2O3)) were administered at three different concentrations and soluble aluminum chloride (AlCl3·6H2O) was used as a reference control at one concentration. A microwave assisted acid digestion approach followed by inductively coupled plasma mass spectrometry (ICP-MS) analysis was developed to analyse the Al burden of individual organs. Special attention was paid on how the sample matrix affected the calibration procedure. After 3 days exposure, AlCl3·6H2O treated animals showed high Al levels in liver and intestine, while upon treatment with Al0 NMs significant amounts of Al were detected only in the latter. In contrast, following Al2O3 NMs treatment, Al was detected in all investigated organs with particular high concentrations in the spleen. A rapid absorption and systemic distribution of all three Al forms tested were found after 3-day oral exposure. The identified differences between Al0 and Al2O3 NMs point out that both, particle shape and surface composition could be key factors for Al biodistribution and accumulation.

Elemental metabolomics

Elemental metabolomics is quantification and characterization of total concentration of chemical elements in biological samples and monitoring of their changes. Recent advances in inductively coupled plasma mass spectrometry have enabled simultaneous measurement of concentrations of > 70 elements in biological samples. In living organisms, elements interact and compete with each other for absorption and molecular interactions. They also interact with proteins and nucleotide sequences. These interactions modulate enzymatic activities and are critical for many molecular and cellular functions. Testing for concentration of > 40 elements in blood, other bodily fluids and tissues is now in routine use in advanced medical laboratories. In this article, we define the basic concepts of elemental metabolomics, summarize standards and workflows, and propose minimum information for reporting the results of an elemental metabolomics experiment. Major statistical and informatics tools for elemental metabolomics are reviewed, and examples of applications are discussed. Elemental metabolomics is emerging as an important new technology with applications in medical diagnostics, nutrition, agriculture, food science, environmental science and multiplicity of other areas.