Serum copper, zinc and lipid peroxidation in pregnant women with preeclampsia in gorgan

Zinc, antioxidant enzymes in preeclampsia, and association with newborn outcome

BACKGROUND

The etiology of preeclampsia (PE) may be associated with the increased of production of reactive species and decreased antioxidant activity of enzymes. Inadequate intake of Zn can affect gestational health due to its biological functions, such as its role in the antioxidant defense system. The study aimed to assess the nutritional status of Zn and antioxidant enzymes in postpartum women and its correlation with neonatal outcomes.

METHODS

A cross-sectional analytical study was carried out at a referral gynecology and obstetrics hospital. A total of 119 women (PE = 58, HP = 61) participated in the study. A quantitative food-frequency questionnaire was used to assess food consumption and further analyze the dietary Zn levels. Zinc levels in plasma and erythrocytes samples were analyzed by flame atomic absorption spectrometry, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels were determined by UV-Vis spectrophotometry.

RESULTS

Plasma and dietary intake Zn results were considered adequate and without statistical difference between groups. SOD levels were significantly higher in the HP group (p = 0.011), and CAT levels were higher in the PE group (p = 0.050). There was a positive correlation between SOD activity in women with PE and the weight of their newborns (r = 0.336, p=0.021).

CONCLUSION

The results showed adequate Zn levels (consumption and serum levels) in the groups studied, although with a reduction of plasma Zn in the PE group compared to the PH group. Zinc in plasma fractions and erythrocytes are important markers for oxidative stress, in particular, plasma Zn seems to be related to the rapid response to preeclampsia. The activity of antioxidant enzymes was elevated in the groups studied. Better SOD activity improves birth weight in children of pregnant women with preeclampsia.

Genetically predicted circulating concentrations of micronutrients and risk of hypertensive disorders of pregnancy: a Mendelian randomization study

PURPOSE

Epidemiological studies examining the association between circulating micronutrients and the risk of hypertensive disorders during pregnancy (HDP) have produced inconsistent results. Therefore, we conducted a Mendelian randomization (MR) analysis to evaluate the potential causal relationship between micronutrients and HDP.

METHODS

Nine micronutrients (beta-carotene, vitamin B6, vitamin B12, calcium, zinc, selenium, copper, folate, and phosphorus) were selected as the exposure factors. Summary data for gestational hypertension (14,727 cases and 196,143 controls) and preeclampsia/eclampsia (7212 cases and 174,266 controls) were extracted from the FinnGen consortium. The MR analysis employed the inverse variance weighted method and conducted a range of sensitivity analyses.

RESULTS

The inverse variance weighted method indicated no significant causal relationship between nine genetically predicted micronutrient concentrations and gestational hypertension, as well as preeclampsia/eclampsia. Sensitivity analyses suggested the absence of pleiotropy.

CONCLUSION

There is no strong evidence to support the causation between circulating micronutrients and hypertensive disorder during pregnancy.

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.

Placental Mitochondrial Function and Dysfunction in Preeclampsia

The placenta is a vital organ of pregnancy, regulating adaptation to pregnancy, gestational parent/fetal exchange, and ultimately, fetal development and growth. Not surprisingly, in cases of placental dysfunction-where aspects of placental development or function become compromised-adverse pregnancy outcomes can result. One common placenta-mediated disorder of pregnancy is preeclampsia (PE), a hypertensive disorder of pregnancy with a highly heterogeneous clinical presentation. The wide array of clinical characteristics observed in pregnant individuals and neonates of a PE pregnancy are likely the result of distinct forms of placental pathology underlying the PE diagnosis, explaining why no one common intervention has proven effective in the prevention or treatment of PE. The historical paradigm of placental pathology in PE highlights an important role for utero-placental malperfusion, placental hypoxia and oxidative stress, and a critical role for placental mitochondrial dysfunction in the pathogenesis and progression of the disease. In the current review, the evidence of placental mitochondrial dysfunction in the context of PE will be summarized, highlighting how altered mitochondrial function may be a common feature across distinct PE subtypes. Further, advances in this field of study and therapeutic targeting of mitochondria as a promising intervention for PE will be discussed.

Comparison Levels of Copper, Zinc, and Cu/Zn Ratio of in Pre-eclampsia and Normal Pregnancy

Introduction Preeclampsia is a syndrome that occurs in pregnancy, characterized by hypertension, proteinuria and edema. Zinc and copper are micronutrients that play a role in the performance of several important enzymes in the human body, such as CuZnSOD and ACE2 enzymes that play a role in the pathogenesis of severe preeclampsia. Zinc also plays a role in the kallikrein-kinin system in the formation of bradykinin which then acts as a vasodilator. This study plans to compare the level of copper (Cu), Zink (Zn), and Cu/Zn ratio in preeclamtic and normal pregnancy women. Method The study recruited 30 pregnant women with severe preeclampsia who were treated at Dr. Hasan Sadikin Bandung and 30 normal pregnant women at one of the Independent Practice Midwives in the Cibabat area, which was conducted in the period September 2021 - November 2021. This research was an analytical observational study with a cross sectional study design. Cu and Zn levels were examined using  inductively coupleds plasma mass spectrometry (ICP-MS). Chi Square, student’s t test, Mann Whitney and multivariat analysis were used for statistical analysis. Results The results of this study showed that the average Cu levels were higher in severe preeclampsia (mean: 2.149 vs. 2.116 mol/L, p=0.728). The median Zn level in the subjects with severe preeclampsia was higher than in normal pregnancies (58 vs 49 g/dL, p<0.001). The median Cu/Zn ratio in severe preeclampsia subjects was lower than in normal pregnancies (0.034 vs 0.063 g/dL, p=0.021). Conclusion  Zn levels was significantly increased in the preeclampsia group, Cu  levels was not  significantly increased in the preeclampsia group  and the ratio of Cu/Zn levels was significantly  decreased in  preeclampsia group compared to normal pregnancies.  

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.

Maternal Serum Levels of Zinc, Copper, and Thiols in Preeclampsia Patients: a Case-Control Study

Preeclampsia is one of the leading causes of maternal mortality-morbidity, and environmental factors act as the main driving force for the development of disease in genetically lean women. Trace element levels (zinc, copper) and thiol state (total, native thiol) may affect involved risk factors and play a role in the pathogenesis. The objective of our study is to assess trace element and thiol levels in patient and control groups. A total number of 88 pregnant women (in their third trimester) included 43 preeclampsia patients and 45 normotensive pregnant women as controls. The main findings of this study were the significantly elevated copper levels and decreased thiol levels (native and total thiols) in the patient group compared to controls (p < 0.05). Disulfide levels were not statistically different between the groups (p > 0.05). In patients, the predictive cutoff value of copper was 224 μg/dL and was 1.19 for the copper/native thiol ratio. Zinc levels were not statistically different between the two groups. Correlation analysis revealed no relationship between zinc-copper and zinc-total thiol levels in patients, while a positive correlation was evident in controls (zinc-copper, p < 0.05, r = 0.425, and zinc-total thiol levels, p < 0.05, r = 0.642). Patients had marginally high ALT and AST values in the normal range, and a significant difference was found between the two groups (p < 0.05). According to these results, elevated copper levels and decreased thiol levels may have a value for early prediction. The mechanisms that may be responsible for the altered element and thiol status have been discussed here in the context of oxidative stress.

Interactions of neurokinin B with copper(II) ions and their potential biological consequences

Preeclampsia is a blood pressure disorder associated with significant proteinuria. Hypertensive women have increased levels of neurokinin B (NKB) and Cu(II) ions in blood plasma during pregnancy. NKB bears the...

Maternal Serum Zinc Level and Pre-eclampsia Risk in African Women: a Systematic Review and Meta-analysis

Some studies have reported the association between maternal serum zinc (Zn) levels and pre-eclampsia. However, many studies have reported controversial results. Hence, this systematic review and meta-analysis was planned to generate summarized evidence on the association between maternal serum Zn levels and pre-eclampsia in African women. Four electronic databases such as PubMed, Hinari, Google Scholar, and African Journals Online were searched for studies published in English. Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument, and Newcastle-Ottawa Scale were used for data extraction and quality assessment of the included studies. The meta-regression analysis was performed by the Stata 14 software. The standardized mean difference (SMD) values of lipid profiles were computed to assess their association with pre-eclampsia at 95% CI. A total of 12 observational studies were included. The mean values of serum Zn level were significantly lower in pre-eclamptic women as compared with normotensive pregnant women (Zn = 59.40 ± 22.80 μg/dL and 80.24 ± 16.04 μg/dL), respectively. The pooled SMD of Zn was significantly reduced in pre-eclamptic women as compared with normotensive pregnant women with the SMD of -1.45 (95% CI -2.26, -0.65) at 95% CI. In this review, we found that the maternal Zn serum level was significantly reduced in pre-eclamptic women than normotensive pregnant women. This suggests that Zn could be involved in the etio-pathogenesis of pre-eclampsia. However, the specific functions of Zn in pre-eclampsia pathogenesis should be proved in large-scale clinical trial studies.

Copper/Zinc Ratio Can Be a Marker to Diagnose Ectopic Pregnancy and Is Associated with the Oxidative Stress Status of Ectopic Pregnancy Cases

It was aimed to evaluate serum zinc and copper levels and oxidative stress parameters in ectopic pregnancy cases, healthy pregnant women, and healthy non-pregnant women. In this cross-sectional case-control study, 30 patients diagnosed with tubal ectopic pregnancy in the gynecology clinic of a tertiary hospital constituted the study group. A healthy pregnant control group (n = 30) was formed of age, body mass index (BMI), and gestational week-matched subjects, and a healthy non-pregnant control group (n = 30) was formed of age and BMI-matched women. The groups were compared in terms of demographic characteristics and laboratory parameters including serum zinc (Zn) level, serum copper (Cu) level, serum malondialdehyde (MDA) level, serum catalase (CAT) activity, serum glutathione peroxidase (GPX) activity, and serum superoxide dismutase (SOD) activity. The groups were similar in respect of demographic characteristics. In the ectopic pregnancy group, serum GPX activity and Cu level were significantly lower, and serum SOD and CAT activity and Zn and MDA levels were higher compared with those of the healthy pregnant and healthy non-pregnant groups. The Cu/Zn ratio showed a significant, positive correlation with the serum GPX activity and serum progesterone level and a negative correlation with serum SOD and CAT activity. When 1.14 was taken as the cutoff value, sensitivity and specificity of the Cu/Zn ratio to determine ectopic pregnancy were 73.3% and 80.0%, respectively. Comparing the area under curve (AUC) in the ROC (receiver operating characteristic) curve analysis, the Cu/Zn ratio was determined to be more valuable than the Cu or Zn values alone in predicting ectopic pregnancy. In correlation analysis, serum beta hCG level showed a negative correlation with SOD and CAT activities and Zn levels. Serum progesterone level showed a negative correlation with serum CAT and SOD activities and MDA and zinc levels and a positive correlation with serum GPX activity and serum copper level (p < 0.05 for all). The current study can be considered of value as the first study in literature to show a significantly lower serum Zn level and higher serum Cu level in ectopic pregnancy cases compared with healthy pregnant control cases. This is also the first study to have revealed an association between the serum Cu/Zn ratio, oxidative status, and ectopic pregnancy. Furthermore, the serum Cu/Zn ratio was found to be useful in the diagnosis of ectopic pregnancy cases.

Evaluation of Zinc and Homocysteine Status in Pregnant Women and Their Association with Pre-eclampsia in Jordan

Pre-eclampsia (PE) is considered a major complication of pregnancy. Hyperhomocyteinemia (H-Hcy) has been proposed to be associated with a number of placenta-mediated diseases, such as PE. Zinc (Zn) is involved in the regulation of total homocysteine (Hcy) levels. A case-control study design was used to examine serum Zn and Hcy statuses, and their association to PE risk. Thirty pregnant women with PE 21∼35 years of age, and 30 matched healthy pregnant women were recruited from Amman, Jordan. Plasma Hcy was measured using liquid chromatography-mass spectrometry, and Zn was measured using atomic absorption. Hcy levels were significantly higher among women with PE compared with controls (16.35±0.43 and 7.25±0.21 μmol/L, respectively; P<0.05). However, there was no significant difference in Zn levels between women with PE and controls (65.37±1.27 and 63.71±1.24 μg/dL, respectively; P>0.05). Blood levels of Hcy (μmol/L) were positively associated with systolic and diastolic blood pressure (β=3.54 and β=1.81, respectively; P<0.05), and Zn levels [odds ratios (OR)=0.84; 95% confidence intervals (CI): 0.71∼0.98] were significantly associated with PE risk (P<0.05). Although women with PE had significantly higher Hcy levels than controls, H-Hcy was not associated with increased PE risk. However, there was a strong association between severity of hypertension and serum Hcy levels, and serum Zn levels were inversely associated with H-Hcy. The likelihood of PE was significantly higher in women who were Zn deficient compared with healthy controls. To conclude, early management of H-Hcy and associated risk factors may be effective in decreasing the incidence of PE.

Serum antioxidant micronutrient levels in pre-eclamptic pregnant women in Enugu, south-East Nigeria: a comparative cross-sectional analytical study

BACKGROUND

Pre-eclampsia is a common obstetric complication of pregnancy in Nigeria, and oxidative stress has been implicated in its aetiopathogenesis. Despite this fact, there is a paucity of information regarding the serum antioxidant micronutrient status of pre-eclamptic Nigerian women. The objective of the was to determine the mean serum levels of some antioxidant trace elements (copper, zinc, selenium, magnesium, manganese) in pre-eclamptic pregnant women and compare with that of healthy pregnant women in Enugu, South-Eastern, Nigeria.

METHODS

A cross-sectional analytical study was carried out at the Obstetrics and Gynaecology department of the University of Nigeria, Teaching Hospital Ituku-Ozalla, Enugu. Using atomic absorption spectrophotometry, the sera of 81 pregnant pre-eclamptic and 81 matched healthy pregnant controls were analyzed for the antioxidant micronutrients. Both descriptive and inferential analysis was performed using the statistical package for social sciences (SPSS) version 21.0 and a P value of < 0.05 was considered to be statistically significant.

RESULTS

The mean serum levels of copper, selenium, and magnesium were found to be significantly lower in the pre-eclamptic pregnant group when compared to the healthy pregnant controls (p < 0.05). The mean serum levels of zinc and manganese did not differ between the two groups (p > 0.05). All the mean serum levels of micro-nutrients studied did not vary by category of pre-eclampsia (with or without severity findings) except manganese which was significantly lower in pre-eclamptic women without severity findings when compared to those with severity findings (p = 0.043).

CONCLUSIONS

The serum levels of copper, selenium, and magnesium were significantly lower among pre-eclamptics when compared to their normal healthy controls. Low levels of selenium, copper, and magnesium may have contributed to the incidence of pre-eclampsia in our environment.

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

OBJECTIVES

Data on the elemental status, redistribution of the elements, role of occupational exposure and dietary assessment in preeclampsia (PE) are scarce. There are many disparities in the findings of essential and non-essential elements' role in PE. In this article we overview the changes in the content of selected elements in pregnancy complicated with the disorder of complex and not fully understood etiology. We have focused on important limitations and highlighted shortcomings in research from the last ten years period.

METHODS

The Scopus and PubMed electronic databases have been searched for English-language articles published within the time interval 2008-2018, with full text available and with the key words "preeclampsia" and "chemical element" (i.e. separately: Cd, Pb, As, Ni, Mo, Co, Cr, Mn, Se, I, Fe, Sr, Cu, Zn, Mg, K and Na) appearing in the title, abstract or keywords.

RESULTS

A total of 48 publications were eligible for this overview. Surprisingly only 4% of papers considered environmental exposure, 8%- diet and 2 %- comorbid diseases. In most published papers, occupational exposure was neglected. Meta-analysis was possible for seven elements in serum (Ca, Cu, Fe, Mg, Mn, Se, Zn), and two elements (Se, Zn) in plasma. It showed negative shift for most elements, however only several were statistically significant.

CONLUSIONS

The overview of the published data on PE and chemical elements yields varied results. Some of the reasons may be the difference in not duly validated method of determination, and huge discrepancies in study designs. The lack of detailed description of studied and control population and small number of samples constitute the most common limitations of such studies. Many of them describe the use of a single analytical procedure, therefore the quality of research may be insufficient to obtain reliable results. A history of elements' status and intake before and during pregnancy is usually not examined. Dietary assessment should be done at different stages of pregnancy, and whenever possible in the periconceptional period as well. It still needs to be established whether the deficiency of certain elements or their excess may be an etiopathogenic factor and a developmental cause of PE, and if it may serve as a target of actions in the causal treatment or even prevention of the occurrence of this disease.

First Trimester Serum Copper or Zinc Levels, and Risk of Pregnancy-Induced Hypertension

Early identification of women at risk of developing pregnancy-induced hypertension (PIH) is very important. The involvement of copper (Cu) and zinc (Zn) in the oxidative balance suggests the possibility of their association with this disease, in which oxidative stress plays a key role. However, it has not been established so far whether the microelement levels in early pregnancy may be risk markers of the disease, as prospective studies are limited in number. In our innovative single-center study, we identified from a prospective cohort of healthy women in the 10–14th week of a single pregnancy: women subsequently developing pregnancy-induced hypertension (n = 121) and matched women remaining normotensive (n = 363). We measured the concentrations of microelements in the serum from 10–14 week, using the inductively coupled plasma mass spectrometry (ICP-MS). The odds ratios of the disease (and 95% confidence intervals) were assessed in logistic regression. In the whole cohort, the odds ratio (OR) of PIH was 1.52 (p = 0.174) for women in the lowest (Q1) quartile of Cu (≤1540.58 µg/L) compared with women in the highest (Q4) quartile (>1937.46 µg/L), but adjusted odds ratio (AOR) was 2.17 (p = 0.019) after adjusted for pre-pregnancy body mass index (BMI) and gestational age at recruitment. The higher levels of Cu in the subgroup of BMI ≥ 25 kg/m² compared to normal BMI were found (1847.64 vs. 1673.36 µg/L; p < 0.0001). In the subgroup of women with the normal pre-pregnancy BMI, the adjusted odds ratio of PIH was AOR = 2.95 (p = 0.040) for Q1 vs. Q4 quartile. Our results suggest that lower Cu levels in early pregnancy may be connected with higher risk of PIH, but BMI affected estimated odds ratios. Zinc levels had no effect on the risk.

A review of copper concentrations in Iranian populations

Copper contamination is increasing and can be a threat to human health. This review tries to summarize copper levels measured in humans in Iran. Persian databases such as SID, Magiran, and IranMedex and English databases such as Scopus, Pubmed, Science Direct, and the Google Scholar were searched using both English and Persian keywords. Twenty-six articles that measured the concentration of copper in human samples in Iran were included. According to the results of the reviewed studies, copper levels in some Iranian populations were higher than normal levels. These populations included pregnant women with preeclampsia, patients with oral cancer, patients with Giardiasis infection, patients with Parkinson's, children under the age of 12 years with β-thalassemia major, pregnant women in the third trimester, and type 2 diabetic patients. Copper levels were less than normal, in patients with tuberculosis after treatment and post-menopausal women with osteopenia and osteoporosis. Also, copper concentrations in patients with tuberculosis, cutaneous leishmaniasis, brucellosis, and molybdenum unit workers were higher, and copper concentrations in patients with Pemphigus vulgaris and coronary artery disease were less than those of their controls, but all were in the normal range (70-140 μg/dL). The amount of copper adsorption in various teeth was different. High levels of copper have been reported in some Iranian populations and this can be a threat to human health. Monitoring copper levels in some Iranian populations is necessary.

Is a high serum copper concentration a risk factor for implantation failure?

Background

Copper-containing contraceptive devices may deposit copper ions in the endometrium, resulting in implantation failure. The deposition of copper ions in many organs has been reported in patients with untreated Wilson’s disease. Since these patients sometimes exhibit subfertility and/or early pregnancy loss, copper ions were also considered to accumulate in the uterine endometrium. Wilson’s disease patients treated with zinc successfully delivered babies because zinc interfered with the absorption of copper from the gastrointestinal tract. These findings led to the hypothesis that infertile patients with high serum copper concentrations may have implantation failure due to the excess accumulation of copper ions. The relationship between implantation (pregnancy) rates and serum copper concentrations has not yet been examined. The Japanese government recently stated that actual copper intake was higher among Japanese than needed. Therefore, the aim of the present study was to investigate whether serum copper concentrations are related to the implantation (pregnancy) rates of human embryos in vivo.

Methods

We included 269 patients (age <40 years old) who underwent vitrifying and warming single embryo transfer with a hormone replacement cycle using good blastocysts (3BB or more with Gardner’s classification). Serum hCG, copper, and zinc concentrations were measured 16 days after the first date of progesterone replacement. We compared 96 women who were pregnant without miscarriage at 10 weeks of gestation (group P) and 173 women who were not pregnant (group NP).

Results

No significant differences were observed in age or BMI between the groups. Copper concentrations were significantly higher in group NP (average 193.2 μg/dL) than in group P (average 178.1 μg/dL). According to the area under the curve (AUC) on the receiver operating characteristic curve for the prediction of clinical pregnancy rates, the Cu/Zn ratio (AUC 0.64, 95% CI 0.54–0.71) was a better predictor than copper or zinc. When we set the cut-off as 1.59/1.60 for the Cu/Zn ratio, sensitivity, specificity, the positive predictive value, and negative predictive value were 0.98, 0.29, 0.71, and 0.88, respectively.

Conclusions

Our single-center retrospective study suggests that high serum copper concentrations (high Cu/Zn ratio) are a risk factor for implantation failure.

High serum copper level is associated with an increased risk of preeclampsia in Asians: A meta-analysis

Epidemiological studies evaluating the associations between serum copper and ratios of Cu/Zn and the preeclampsia (PE) risk in Asian population have produced inconsistent results. Therefore, we conducted a meta-analysis to summarize the relationships. We hypothesize that higher serum copper and ratios of Cu/Zn may increase the PE risk. A systematic literature search was performed in PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure (CNKI), VIP (Database of Chinese Scientific and Technical Periodicals) and Wangfang databases for relevant studies up to November 2016. Pooled standardized mean difference (SMD) was calculated with random effects model. The results showed that PE patients had a higher serum copper level [SMD (95% CI): 1.05 (0.34, 1.77), Z=2.88, P for Z=0.004; I²=96.9%, P for I²<0.0001] compared with healthy pregnancy controls. In subgroup analyses, a higher serum copper level in PE patients was observed in case-control studies [SMD (95% CI): 1.39 (0.44, 2.34)]. No significant difference was found between PE patients and healthy pregnancy controls for ratios of Cu/Zn [(SMD (95% CI): 0.26 (-0.77, 1.29), Z=0.49, P for Z=0.625; I²=95.8%, P for I²<0.0001)]. In conclusion, our meta-analysis indicates that a higher serum copper level is associated with an increased risk of PE. Further studies are needed to confirm these results in future research.

Association between Maternal Zinc Status, Dietary Zinc Intake and Pregnancy Complications: A Systematic Review

Adequate zinc stores in the body are extremely important during periods of accelerated growth. However, zinc deficiency is common in developing countries and low maternal circulating zinc concentrations have previously been associated with pregnancy complications. We reviewed current literature assessing circulating zinc and dietary zinc intake during pregnancy and the associations with preeclampsia (PE); spontaneous preterm birth (sPTB); low birthweight (LBW); and gestational diabetes (GDM). Searches of MEDLINE; CINAHL and Scopus databases identified 639 articles and 64 studies were reviewed. In 10 out of 16 studies a difference was reported with respect to circulating zinc between women who gave birth to a LBW infant (≤2500 g) and those who gave birth to an infant of adequate weight (>2500 g), particularly in populations where inadequate zinc intake is prevalent. In 16 of our 33 studies an association was found between hypertensive disorders of pregnancy and circulating zinc; particularly in women with severe PE (blood pressure ≥160/110 mmHg). No association between maternal zinc status and sPTB or GDM was seen; however; direct comparisons between the studies was difficult. Furthermore; only a small number of studies were based on women from populations where there is a high risk of zinc deficiency. Therefore; the link between maternal zinc status and pregnancy success in these populations cannot be established. Future studies should focus on those vulnerable to zinc deficiency and include dietary zinc intake as a measure of zinc status.

A meta-analysis of copper level and risk of preeclampsia: evidence from 12 publications

The association between copper level and risk of preeclampsia (PE) has produced inconsistent results. Thus, a meta-analysis was conducted to summarize the evidence from epidemiological studies for copper level and PE risk. Pertinent studies were identified by a search of PubMed and Web of Knowledge up to April 2016. Standardized mean difference (SMD) was performed to combine the results. Random-effect model (REM) was used. Publication bias was estimated using Egger's regression asymmetry test. Twelve articles (10 case–control studies and 2 cross-sectional studies) involving 442 PE cases and 463 health controls were included in this meta-analysis. Our pooled results suggested that PE patients had a higher copper level compared with healthy pregnancy controls [summary SMD=0.69, 95% CI: 0.54–0.84, I²=96.7%; P<0.001]. The association was also significant in Asian population [SMD=0.73, 95% CI=0.57–0.90, I²=97.3%] and European populations [SMD=0.50, 95% CI=0.14–0.86, I²=58.9%]. After conducting the subgroup analysis and sensitive analysis, the results showed consistent significant association with the one based on all studies. No publication biases were found. Our analysis indicated that plasma or serum copper level in PE patients was significantly higher than that in healthy pregnancy women.

Association between zinc level and the risk of preeclampsia: a meta-analysis

BACKGROUND

Epidemiological studies evaluating the association between zinc level and the risk of preeclampsia have produced inconsistent results. We therefore conducted a meta-analysis to summarize the evidence for them.

METHODS

Pertinent studies were identified by a search in PubMed and Web of Knowledge up to April 2015. Standardized mean difference (SMD) was performed to combine the results. Random-effect model was used. Publication bias was estimated using Egger's regression asymmetry test.

RESULTS

Thirteen articles (11 case-control studies and 2 cross-sectional studies) involving 445 preeclampsia cases and 568 healthy controls were included in this meta-analysis. Our pooled results suggested that preeclampsia patients had a lower zinc level as compared with healthy, pregnant controls (summary SMD = -0.61, 95 % CI = -0.74, -0.48, I (2) = 88.5 %). The association was also significant in Asia (SMD = -0.73, 95 % CI = -0.88, -0.58), but not in Europe. No publication biases were found.

CONCLUSIONS

Our analysis indicated that zinc level in preeclampsia patients was significantly lower than that of healthy, pregnant women, especially among the Asian population.

The Relationship between Serum Zinc Level and Preeclampsia: A Meta-Analysis

The association between serum zinc level and preeclampsia (PE) remains controversial. A systematic literature search was performed in PubMed, Web of Science and Embase for relevant available articles. The articles were limited to those in English from January 1990 to April 2015. Observational studies evaluating the association between serum zinc level and PE were included. The I² was used to assess heterogeneity and the random effect model (REM) was adopted as the pooling method. The pooled standard mean difference (SMD) with 95% confidence interval (CI) was used to estimate the association between serum zinc level and PE. Seventeen observational studies were included. Compared with healthy pregnancy controls, PE patients have lower serum zinc level in 14 studies about total PE (SMD (95% CI): −0.587 (−0.963, −0.212), Z = 3.06, p for Z = 0.002; I² = 88.4%, p for I² < 0.0001). In subgroup analysis, a lower serum zinc level in PE patients compared with healthy pregnancy controls was observed in studies conducted in Asia, studies with zinc level measured in serum, and studies involving fasting participants. The SMD did not differ significantly between studies with healthy pregnancy controls matched by individual age (yes or no), and by individual gestational age (yes or no), respectively. Results from this meta-analysis indicate that serum zinc level in PE patients is significantly lower than that in healthy pregnancy controls. A moderate amount of zinc supplementation during pregnancy is advocated to reduce the incidence of PE.

Changes in Copper, Zinc, and Malondialdehyde Levels and Superoxide Dismutase Activities in Pre-Eclamptic Pregnancies

BACKGROUND

Preeclampsia (PE) is a hypertensive disorder that occurs in 2% to 8% of pregnancies. Although numerous studies have investigated the etiology and pathophysiology of preeclampsia, the precise pathological mechanisms remain poorly understood. Hence, in the present study malondialdehyde (MDA) levels and SOD expression, and Cu and Zn concentrations and ratios were correlated with birth weights in pregnant women with and without PE, and in non-pregnant females of reproductive age.

MATERIAL AND METHODS

Malondialdehyde (MDA) levels and superoxide dismutase (SOD) activities were determined spectrophotometrically, and Cu and Zn levels were determined using atomic absorption spectrometry in serum from 42 non-pregnant women (NP), 40 healthy pregnant women (HP), and 38 pre-eclamptic pregnant (PE) women. Subsequently, Cu/Zn ratios were calculated and associations with birth weights were analyzed using Spearman correlations.

RESULTS

Cu, Zn, and MDA levels and Cu/Zn ratios were significantly higher in the PE group than in the HP and NP groups, and were significantly higher in the HP than in the NP group (p<0.001 and p<0.001; respectively). In contrast, serum Zn and SOD levels were significantly lower in the PE group than in HP and NP groups, and were significantly lower in the HP group than in the NP group (p<0.001 and p<0.001; respectively). However, only Cu and Zn levels were significantly associated with fetal birth weights (r=-0.433, p<0.001).

CONCLUSIONS

Serum Cu/Zn ratios may reflect vascular complications of PE, and the ensuing increases in lipid peroxidation may play important pathogenic roles.