Relationship between copper and lipids and atherogenic indices soon after birth in Japanese preterm infants of 32–35 weeks

Associations between multiple metal exposure and fertility in women: A nested case-control study

Metal pollution can cause a decline in female fertility, however, previous studies have focused more on the effect of a single metal on fertility. In this study, we evaluated the effect of metal mixtures on female fertility based on nested case-control samples. The plasma levels of 22 metal elements from 180 women were determined by an inductively coupled plasma mass spectrometer (ICP-MS). Minimum absolute contraction and selection operator (LASSO) penalty regression selected metals with the greatest influence on clinical outcome. Logistic regression was used to analyze the correlation between single metals and fertility while a Bayesian kernel function regression (BKMR) model was used to analyze the effect of mixed metals. Eight metals (Calcium (Ca), Chromium (Cr), Cobalt (Co), Copper (Cu), Zinc (Zn), Rubidium (Rb), Strontium (Sr) and Zirconium (Zr)) were selected by LASSO regression for subsequent analysis. After adjusting for covariates, the logistic model showed that Cu (Odds Ratio(OR):0.33, 95% CI: 0.13 - 0.84) and Co (OR:0.38, 95% CI: 0.15 -0.94) caused a significant reduction in fertility, and identified the protective effect of Zn (OR: 2.96, 95% CI:1.21 -7.50) on fertility. Trend tests showed that increased Cr, Cu, and Rb levels were associated with reduced fertility. The BKMR model showed that Cr, Co, Cu, and Rb had a nonlinear relationship with fertility decline when controlling for the concentrations of other metals and suggested that Cu and Cr might exert an influence on fertility. Analysis showed a negative correlation between Cu, Cr, Co, Rb, and fertility, and a positive correlation between Zn and fertility. Furthermore, we found evidence for the interaction between Cu and Cr. Our findings require further validation and may identify new mechanisms in the future.

Association of maternal prenatal copper concentration with gestational duration and preterm birth: a multicountry meta-analysis

BACKGROUND

Copper (Cu), an essential trace mineral regulating multiple actions of inflammation and oxidative stress, has been implicated in risk for preterm birth (PTB).

OBJECTIVES

This study aimed to determine the association of maternal Cu concentration during pregnancy with PTB risk and gestational duration in a large multicohort study including diverse populations.

METHODS

Maternal plasma or serum samples of 10,449 singleton live births were obtained from 18 geographically diverse study cohorts. Maternal Cu concentrations were determined using inductively coupled plasma mass spectrometry. The associations of maternal Cu with PTB and gestational duration were analyzed using logistic and linear regressions for each cohort. The estimates were then combined using meta-analysis. Associations between maternal Cu and acute-phase reactants (APRs) and infection status were analyzed in 1239 samples from the Malawi cohort.

RESULTS

The maternal prenatal Cu concentration in our study samples followed normal distribution with mean of 1.92 μg/mL and standard deviation of 0.43 μg/mL, and Cu concentrations increased with gestational age up to 20 wk. The random-effect meta-analysis across 18 cohorts revealed that 1 μg/mL increase in maternal Cu concentration was associated with higher risk of PTB with odds ratio of 1.30 (95% confidence interval [CI]: 1.08, 1.57) and shorter gestational duration of 1.64 d (95% CI: 0.56, 2.73). In the Malawi cohort, higher maternal Cu concentration, concentrations of multiple APRs, and infections (malaria and HIV) were correlated and associated with greater risk of PTB and shorter gestational duration.

CONCLUSIONS

Our study supports robust negative association between maternal Cu and gestational duration and positive association with risk for PTB. Cu concentration was strongly correlated with APRs and infection status suggesting its potential role in inflammation, a pathway implicated in the mechanisms of PTB. Therefore, maternal Cu could be used as potential marker of integrated inflammatory pathways during pregnancy and risk for PTB.

Copper and selenium status as biomarkers of neonatal infections

Neonatal infections are a major risk factor for neonatal mortality. A reliable diagnosis of early-onset sepsis (EOS) is hampered by the variable clinical presentations of the children. We hypothesized that changes in the Se or Cu status, or the biomarkers selenoprotein P (SELENOP) or ceruloplasmin (CP) alone or in combination may be informative of EOS. We generated a new human CP-specific non-competitive immunoassay (ELISA) suitable of analysing small sample volumes and validated the method with a commercial CP source. Using this novel CP assay, we analysed a case-control study of EOS (n = 19 control newborns, n = 18 suspected cases). Concentrations of Se, Cu, SELENOP, CP, interleukin-6 (IL-6), and C-reactive protein (CRP) along with the Cu/Se and CP/SELENOP ratios were evaluated by correlation analyses as biomarkers for EOS. Diagnostic value was estimated by receiver operating characteristic (ROC) curve analyses. The new CP-ELISA displayed a wide working range (0.10-6.78 mg CP/L) and low sample requirement (2 μL of serum, EDTA-, heparin- or citrate-plasma). Plasma CP correlated positively with Cu concentrations in the set of all samples (Pearson r = 0.8355, p < 0.0001). Three of the infected neonates displayed particularly high ratios of Cu/Se and CP/SELENOP, i.e., 3.8- to 6.9-fold higher than controls. Both the Cu/Se and the CP/SELENOP ratios correlated poorly with the early infection marker IL-6, but strongly and positively with the acute-phase protein CRP (Cu/Se-CRP: Spearman ϱ = 0.583, p = 0.011; CP/SELENOP-CRP: ϱ = 0.571, p = 0.013). The ROC curve analyses indicate that a combination of biomarkers for the Se and Cu status do not improve the early identification of EOS considerably. This study established a robust, highly precise, partly validated and scalable novel CP sandwich ELISA suitable for basic and clinical research, requiring minute amounts of sample. The ratio of circulating CP/SELENOP constitutes a promising new composite biomarker for detection of EOS, at least in a subset of severely diseased children.

Association of maternal serum copper during early pregnancy with the risk of spontaneous preterm birth: A nested case-control study in China

BACKGROUND

The effect of maternal copper (Cu) level on the risk of spontaneous preterm birth (SPB) remains debate. Therefore, we conducted a prospective nested case-control study in Shanxi Province to investigate the relationship between maternal serum Cu concentration and SPB risk, as well as the potential mediation effect of lipid metabolism.

METHOD

From an overall cohort of 4229 women, 147 women affected by SPB at 20-36 gestational weeks (cases) and 381 women who delivered at ≥37 gestational weeks (controls) were included in our nested case-control study. Maternal blood samples were collected during 4-22 gestational weeks, and the concentrations of Cu, total cholesterol (TC), and triglycerides (TG) were measured. Information on maternal social demographic characteristics were collected using questionnaires. Unconditional logistic regression models were used to estimate the associations of Cu, TC or TG levels with SPB risk. Linear regressions were used to assess the relationships between concentrations of Cu and TC or TG.

RESULTS

Serum Cu concentrations in the case group (median: 184 μg/dL) were significantly higher than those in the control group (median: 166 μg/dL, p < 0.0001). Compared to the lowest serum Cu levels, the odds ratios associated with SPB increased to 2.02 (95% confidence interval [CI]: 1.07, 3.82), 3.10 (1.54, 6.22) and 4.18 (2.11, 8.27) in the second, third and fourth quartile respectively, after adjusting for sampling time, maternal age, pre-pregnancy BMI, education, occupation, parity, spontaneous abortion history, folic acid use, medication use, pre-pregnancy passive smoking status, child gender and fasting status. Plasma concentrations of TC and TG were positively associated with SPB risk in a dose-dependent manner. However, when stratified by sampling time, the above-mentioned relationships were significant in the first trimester but not in the second. In addition, plasma concentrations of TC and TG were positively correlated with serum Cu concentrations.

CONCLUSIONS

High maternal Cu level in the first trimester may increase the risk of SPB, by potentially increasing plasma concentrations of TC and TG.