Homocysteine, cysteine, and related metabolites in maternal and fetal plasma in preeclampsia

Association of serum homocysteine with vitamin B12 and folate levels in women with pre-eclampsia in a tertiary health care center in Nepal

BACKGROUND

Pre-eclampsia is a syndrome that chiefly includes the development of new-onset hypertension and proteinuria after 20 weeks of pregnancy. Pre-eclampsia is one of the major causes of mortality and morbidity in Nepal. Hyperhomocysteinemia may be a cause of the endothelial dysfunction provoked by oxidative stress in pre-eclampsia. This study was designed to evaluate the association of homocysteine with Vitamin B12 and folate in patients with pre-eclampsia.

METHOD

An observational cross sectional study was performed in the Gynecology and Obstetrics Department of TUTH involving seventy two subjects with pre-eclampsia. Blood pressure, urinary protein levels, serum homocysteine, Vitamin B12 and folate levels were compared in both mild and severe forms of pre-eclampsia. Concentration of Vitamin B12 and folate were measured using Vitros ECI and homocysteine was measured using CLIA. SPSS 23.0 was used to analyze the data. Tests were performed with Mann Whitney Test and Spearman's rank correlation test. A p-value < 0.05 was considered statistically significant.

RESULTS

This study showed no significant difference in age and weeks of gestation in both mild and severe forms of pre-eclampsia. Mean concentration of homocysteine was higher (13.1 ± 6.4 micromol/L) in severe Pre-eclampsia as compared to mild cases (7.6 ± 2.8 micromol/L). Mean concentration of folate was lower in severe cases (35.4 ± 24.1 micromol/L) when compared with mild cases of pre-eclampsia (57 ± 23.4 micromol/L).

CONCLUSION

Homocysteine levels were increased in severe Pre-eclampsia when compared with mild pre-eclampsia and this finding can be used to predict and prevent complications in patients with pre-eclampsia.

Metabolomic prediction of severe maternal and newborn complications in preeclampsia

INTRODUCTION

Preeclampsia (PreE) remains a major source of maternal and newborn complications. Prenatal prediction of these complications could significantly improve pregnancy management.

OBJECTIVES

Using metabolomic analysis we investigated the prenatal prediction of maternal and newborn complications in early and late PreE and investigated the pathogenesis of such complications.

METHODS

Serum samples from 76 cases of PreE (36 early-onset and 40 late-onset), and 40 unaffected controls were collected. Direct Injection Liquid Chromatography-Mass Spectrometry combined with Nuclear Magnetic Resonance (NMR) spectroscopy was performed. Logistic regression analysis was used to generate models for prediction of adverse maternal and neonatal outcomes in patients with PreE. Metabolite set enrichment analysis (MSEA) was used to identify the most dysregulated metabolites and pathways in PreE.

RESULTS

Forty-three metabolites were significantly altered (p < 0.05) in PreE cases with maternal complications and 162 metabolites were altered in PreE cases with newborn adverse outcomes. The top metabolite prediction model achieved an area under the receiver operating characteristic curve (AUC) = 0.806 (0.660-0.952) for predicting adverse maternal outcomes in early-onset PreE, while the AUC for late-onset PreE was 0.843 (0.712-0.974). For the prediction of adverse newborn outcomes, regression models achieved an AUC = 0.828 (0.674-0.982) in early-onset PreE and 0.911 (0.828-0.994) in late-onset PreE. Profound alterations of lipid metabolism were associated with adverse outcomes.

CONCLUSION

Prenatal metabolomic markers achieved robust prediction, superior to conventional markers for the prediction of adverse maternal and newborn outcomes in patients with PreE. We report for the first-time the prediction and metabolomic basis of adverse maternal and newborn outcomes in patients with PreE.

Plasma trimethylamine N-oxide metabolites in the second trimester predict the risk of hypertensive disorders of pregnancy: a nested case-control study

The relationship between gut microbiota products trimethylamine oxide (TMAO) and related metabolites including betaine, choline and L-carnitine and hypertensive disorders of pregnancy (HDP) is unclear. In order to examine whether plasma TMAO and related metabolites predict the risk of HDP, a nested case-control study was conducted in Chinese women based on a prospective cohort including 9447 participants. 387 pairs of pregnant women (n = 774) were matched and their plasma TMAO, betaine, choline, and L-carnitine at 16-20 gestational weeks were measured by liquid chromatography-mass spectrometry. Odds ratio (OR) and the 95% confidence interval (95% CI) were calculated using the conditional logistic regression, to examine the association between TMAO metabolites and HDP. The findings showed that higher plasma betaine (≥24.94 μmol/L) was associated with a decreased risk of HDP and its subtype gestational hypertension (GH), with adjusted ORs of 0.404 (95% CI: 0.226-0.721) and 0.293 (95% CI: 0.134-0.642), respectively. Higher betaine/choline ratio (>2.64) was associated with a lower risk of HDP and its subtype preeclampsia or chronic hypertension with superimposed preeclampsia (PE/CH-PE), with adjusted ORs of 0.554 (95% CI: 0.354-0.866) and 0.226 (95% CI: 0.080-0.634). Moreover, compared with traditional factors (TFs) model, the TMAO metabolites+ TFs model had a higher predictive ability for PE/CH-PE (all indexes P values < 0.0001). Therefore, it suggests that the detection of plasma betaine and choline in the early second trimester of pregnancy can better assess the risk of HDP.

Effect of the Probiotic Bacillus subtilis DE-CA9TM on Fecal Scores, Serum Oxidative Stress Markers and Fecal and Serum Metabolome in Healthy Dogs

BACKGROUND

There is increasing interest in the use of Bacillus species as probiotics since their spore-forming ability favors their survival in the acidic gastric environment over other probiotic species. The subsequent germination of B. subtilis to their vegetative form allows for their growth in the small intestine and may increase their beneficial effect on the host. B. subtilis strains have also previously been shown to have beneficial effects in humans and production animals, however, no reports are available so far on their use in companion animals.

STUDY DESIGN

The goal of this study was therefore to investigate the daily administration of 1 × 109 cfu DE-CA9TM orally per day versus placebo on health parameters, fecal scores, fecal microbiome, fecal metabolomics, as well as serum metabolomics and oxidative stress markers in ten healthy Beagle dogs in a parallel, randomized, prospective, placebo-controlled design over a period of 45 days.

RESULTS

DE-CA9TM decreased the oxidative status compared to controls for advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS) and reactive oxygen metabolites (d-ROMS), suggesting an antioxidant effect of the treatment. Fecal metabolomics revealed a significant reduction in metabolites associated with tryptophan metabolism in the DE-CA9TM-treated group. DE-CA9TM also significantly decreased phenylalanine and homocysteine and increased homoserine and threonine levels. Amino acid metabolism was also affected in the serum metabolome, with increased levels of urea and cadaverine, and reductions in N-acetylornithine in DE-CA9TM compared to controls. Similarly, changes in essential amino acids were observed, with a significant increase in tryptophan and lysine levels and a decrease in homocysteine. An increase in serum guanine and deoxyuridine was also detected, with a decrease in beta-alanine in the animals that ingested DE-CA9TM.

CONCLUSIONS

Data generated throughout this study suggest that the daily administration of 1 × 109 cfu of DE-CA9TM in healthy Beagle dogs is safe and does not affect markers of general health and fecal scores. Furthermore, DE-CA9TM administration had a potential positive effect on some serum markers of oxidative stress, and protein and lipid metabolism in serum and feces.

One-carbon metabolism-related nutrients intake is associated with lower risk of preeclampsia in pregnant women: a matched case-control study

Many studies have suggested that folate plays a role in preeclampsia (PE) risks, but few studies have assessed folate-related 1-carbon metabolism (OCM)-related nutrients with the risk of PE. We hypothesized that OCM-related nutrients are associated with PE. A 1:1 matched case-control study was conducted to explore the association between dietary OCM-related nutrients intake and the risk of PE in pregnant Chinese women. Four hundred and forty pairs of pregnant women with PE and hospital-based, healthy pregnant women, matched according to gestational week (±1 week) and age (±3 years), were recruited. Dietary intake was assessed using a validated 78-item semiquantitative food frequency questionnaire. Multivariate conditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs. Restricted cubic splines were plotted to evaluate the dose-response relationship between dietary OCM-related nutrient intake and the risk of PE. Intake of folate, vitamin B₆, vitamin B₁₂, methionine, and total choline were inversely related to the risk of PE after adjustment for covariates (all P trend < .05). Adjusted ORs (95% CIs) for quartile 4 versus quartile 1 were 0.71 (0.55-0.93) for folate, 0.66 (0.50-0.87) for vitamin B₆, 0.68 (0.52-0.88) for vitamin B₁₂, 0.77 (0.60-0.81) for methionine, and 0.67 (0.51-0.87) for total choline. This study suggests that dietary OCM-related nutrients intake is associated with lower odds of PE in pregnant Chinese women.

Homocysteine Metabolism in Pregnancy and Developmental Impacts

Homocysteine is a metabolite generated by methionine cycle metabolism, comprising the demethylated derivative of methionine. Homocysteine can be metabolised by the transsulphuration pathway to cystathionine, which requires vitamin B6, or can undergo remethylation to methionine. Homocysteine remethylation to methionine is catalysed by methionine synthase activity which requires vitamin B12, regenerating methionine to allow synthesis of the universal methyl donor S-adenosylmethionine required for methylation and gene transcription regulation. The methyl-group donated for homocysteine remethylation comes from 5-methyltetrahydrofolate generated by the folate cycle, which allows tetrahydrofolate to be returned to the active folate pool for nucleotide biosynthesis. Therefore the integrated actions of the methionine and folate cycles, required to metabolise homocysteine, also perpetuate methylation and nucleotide synthesis, vitally important to support embryonic growth, proliferation and development. Dysregulated activities of these two interdependent metabolic cycles, arising from maternal suboptimal intake of nutrient co-factors such as folate and vitamin B12 or gene polymorphisms resulting in reduced enzymatic activity, leads to inefficient homocysteine metabolic conversion causing elevated concentrations, known as hyperhomocysteinemia. This condition is associated with multiple adverse pregnancy outcomes including neural tube defects (NTDs). Raised homocysteine is damaging to cellular function, binding to proteins thereby impairing their function, with perturbed homocysteine metabolism impacting negatively on embryonic development. This review discusses the "cross-talk" of maternal-fetal homocysteine interrelationships, describes the placental transport of homocysteine, homocysteine impacts on pregnancy outcomes, homocysteine and methylation effects linking to NTD risk and proposes a putative pathway for embryonic provision of folate and vitamin B12, homocysteine-modulating nutrients that ameliorate NTD risk.

Identification of Biomarkers for Preeclampsia Based on Metabolomics

Background

Preeclampsia (PE) is a significant cause of maternal and neonatal morbidity and mortality worldwide. However, the pathogenesis of PE is unclear and reliable early diagnostic methods are still lacking. The purpose of this review is to summarize potential metabolic biomarkers and pathways of PE, which might facilitate risk prediction and clinical diagnosis, and obtain a better understanding of specific metabolic mechanisms of PE.

Methods

This review included human metabolomics studies related to PE in the PubMed, Google Scholar, and Web of Science databases from January 2000 to November 2021. The reported metabolic biomarkers were systematically examined and compared. Pathway analysis was conducted through the online software MetaboAnalyst 5.0.

Results

Forty-one human studies were included in this systematic review. Several metabolites, such as creatinine, glycine, L-isoleucine, and glucose and biomarkers with consistent trends (decanoylcarnitine, 3-hydroxyisovaleric acid, and octenoylcarnitine), were frequently reported. In addition, eight amino acid metabolism-related, three carbohydrate metabolism-related, one translation-related and one lipid metabolism-related pathways were identified. These biomarkers and pathways, closely related to renal dysfunction, insulin resistance, lipid metabolism disorder, activated inflammation, and impaired nitric oxide production, were very likely to contribute to the progression of PE.

Conclusion

This study summarized several metabolites and metabolic pathways, which may be associated with PE. These high-frequency differential metabolites are promising to be biomarkers of PE for early diagnosis, and the prominent metabolic pathway may provide new insights for the understanding of the pathogenesis of PE.

NRF2-Dependent Placental Effects Vary by Sex and Dose following Gestational Exposure to Ultrafine Particles

Exposure to ultrafine particles (UFPs, PM0.1) during pregnancy triggers placental oxidative stress and inflammation, similar to fine PM (PM2.5). The Nrf2 gene encodes a redox-sensitive transcription factor that is a major regulator of antioxidant and anti-inflammatory responses. Disruption of NRF2 is known to substantially enhance PM2.5-driven oxidant and inflammatory responses; however, specific responses to UFP exposure, especially during critical windows of susceptibility such as pregnancy, are not fully characterized; To investigate the role of NRF2 in regulating maternal antioxidant defenses and placental responses to UFP exposure, wildtype (WT) and Nrf2-/- pregnant mice were exposed to either low dose (LD, 100 µg/m3) or high dose (HD, 500 µg/m3) UFP mixture or filtered air (FA, control) throughout gestation; Nrf2-/- HD-exposed female offspring exhibited significantly reduced fetal and placental weights. Placental morphology changes appeared most pronounced in Nrf2-/- LD-exposed offspring of both sexes. Glutathione (GSH) redox analysis revealed significant increases in the GSH/GSSG ratio (reduced/oxidized) in WT female placental tissue exposed to HD in comparison with Nrf2-/- HD-exposed mice. The expression of inflammatory cytokine genes (Il1β, Tnfα) was significantly increased in Nrf2-/- placentas from male and female offspring across all exposure groups. Genes related to bile acid metabolism and transport were differentially altered in Nrf2-/- mice across sex and exposure groups. Notably, the group with the most marked phenotypic effects (Nrf2-/- HD-exposed females) corresponded to significantly higher placental Apoa1 and Apob expression suggesting a link between placental lipid transport and NRF2 in response to high dose UFP exposure; Disruption of NRF2 exacerbates adverse developmental outcomes in response to high dose UFP exposure in female offspring. Morphological effects in placenta from male and female offspring exposed to low dose UFPs also signify the importance of NRF2 in maternal-fetal response to UFPs.

Effects of Dietary Choline Levels During Pregnancy on Reproductive Performance, Plasma Metabolome and Gut Microbiota of Sows

This study investigated the effects of dietary choline levels during gestation on reproductive performance of sows. In addition, the plasma metabolome and gut microbiota of sows was studied. A total of 260 multiparous sows were allocated to five dietary treatment groups with increasing choline concentrations (1,050, 1,450, 1,850, 2,250, and 2,650 mg/kg) in a randomized complete block design. The sows were fed experimental diets from breeding until farrowing and a common lactating diet during lactation. The results showed that the backfat (BF) gain of sows during gestation, individual birth weight for total piglets born, piglets born alive, average piglet weight at weaning increased linearly (P < 0.05), whereas the within-litter birth weight variation coefficient (CV) of piglets born alive and suckling piglet mortality decreased linearly (P < 0.05) as dietary choline level increased. A quadratic effect of dietary choline level was observed for the average daily feed intake (ADFI) of sows during lactation (P < 0.05). ADFI was maximized when the dietary choline concentration reached 1,910 mg/kg. Plasma H2O2 concentration at day 30 of gestation in the 1,050 mg/kg group was greater than that in the 1,850 and 2,650 mg/kg groups (P < 0.05). Plasma metabolomics identified 46 metabolites among the three groups. Specifically, plasma concentrations of trimethylamine-N-oxide (TMAO), dopamine, and L-proline increased while 1-methylhistidine concentration decreased as dietary choline levels increased. In addition, bacterial observed species and richness (Chao 1 and ACE) at day 110 of gestation decreased as dietary choline levels increased (P < 0.05). For the gut microbiota composition, the enhanced dietary choline level decreased the abundance of phylum Proteobacteria (P < 0.05) and increased the abundance of phylum Actinobacteria (P < 0.05) at day 30 of gestation. Compared with the 1,050 mg/kg group, the abundance of genus Terrisporobacter was less in the 1,850 mg/kg group, and genera Bacillus and Cellulomonas were greater in the 2,650 mg/kg group. In summary, increasing dietary choline levels improved the birth weight, uniformity of neonatal piglets and litter performance during lactation. This may be associated with better antioxidant capability, metabolic status, and gut microbiota of sows during gestation.

Maternal plasma choline and betaine in late pregnancy and child growth up to age 8 years in the KOALA Birth Cohort Study

BACKGROUND

Sufficient choline and betaine during pregnancy are needed for fetal growth and development.

OBJECTIVES

We aimed to investigate the associations between maternal plasma choline and betaine in the third trimester of pregnancy and child growth from birth up to 8 years of age.

METHODS

Concentrations of choline and betaine were measured in plasma of 1331 pregnant women from the KOALA (Kind, Ouders en gezondheid: Aandacht voor Leefstijl en Aanleg) Birth Cohort Study in the Netherlands. Child weight and height were measured at birth and at 1 (91% complete), 2 (86%), and 6-8 y (76%). Birth weight, weight gain in the first year, and z scores for weight and height at 1 and 2 y were used as continuous outcome variables. BMI z scores at 1 and 2 y were used as continuous and dichotomous outcomes, and BMI z scores at age 6-8 y were used to study overweight at that age.

RESULTS

Each 1-µmol/L increase of maternal plasma choline was associated with a mean 20-g (95% CI: 1.1, 38.0 g) higher weight gain in the first year of life, and a higher BMI z score (β: 0.02; 95% CI: 0.00, 0.04) and slightly higher odds of BMI z score >85th percentile (OR: 1.08; 95% CI: 1.03, 1.10) at 1-2 y. Each 1-µmol/L increase of plasma betaine was associated with a mean 12-g (95% CI: 0.8, 23.9 g) higher weight gain in the first year of life and higher odds of BMI z score >85th percentile at 1-2 y (OR: 1.03; 95% CI: 1.00, 1.07). Lastly, betaine was associated with overweight at 6-8 y (OR: 1.17; 95% CI: 1.02, 1.34), only in boys.

CONCLUSIONS

Third-trimester pregnancy plasma choline and betaine were positively associated with childhood anthropometric measures. In boys, some of the associations may have persisted up to 8 y of age. Further studies may investigate the validity of maternal plasma choline and betaine concentrations as markers of maternal intake and fetal transfer.

Association between abnormal maternal serum levels of vitamin B12 and preeclampsia: a systematic review and meta-analysis

CONTEXT

Some evidence has shown an association between maternal vitamin B12 levels and the development of preeclampsia in pregnant women, but the relationship between preeclampsia and vitamin B12 is not clear.

OBJECTIVE

The aim of this systematic review was to compare serum vitamin B12 levels in women with preeclampsia with those in normotensive pregnant women.

DATA SOURCES

The PubMed/MEDLINE, Scopus, and Web of Science databases were searched up to August 2019, along with the reference lists of included articles.

STUDY SELECTION

The literature was searched for observational studies that investigated vitamin B12 levels in women with preeclampsia.

DATA EXTRACTION

Data were extracted independently by 2 authors. Data were pooled using a random-effects model.

RESULTS

Vitamin B12 levels in women with preeclampsia were significantly lower than those in healthy women (mean, -15.24 pg/mL; 95%CI, -27.52 to -2.954; P < 0.015), but heterogeneity between studies was high (I2 = 97.8%; P = 0.0103). Subgroup analyses based on folic acid supplementation, homocysteine concentrations, and gestational age at the time of sampling for vitamin B12 assessment did not identify the sources of heterogeneity.

CONCLUSIONS

Women with preeclampsia had significantly lower vitamin B12 concentrations than normotensive pregnant women.

Umbilical cord blood metabolome differs in relation to delivery mode, birth order and sex, maternal diet and possibly future allergy development in rural children

Allergy is one of the most common diseases among young children yet all factors that affect development of allergy remain unclear. In a small cohort of 65 children living in the same rural area of south-west Sweden, we have previously found that maternal factors, including prenatal diet, affect childhood allergy risk, suggesting that in utero conditions may be important for allergy development. Here, we studied if metabolites in the umbilical cord blood of newborns may be related to development of childhood allergy, accounting for key perinatal factors such as mode of delivery, birth order and sex. Available umbilical cord blood plasma samples from 44 of the participants were analysed using gas chromatography-mass spectrometry metabolomics; allergy was diagnosed by specialised paediatricians at ages 18 months, 3 years and 8 years and included eczema, asthma, food allergy and allergic rhinoconjunctivitis. Nineteen cord blood metabolites were related to future allergy diagnosis though there was no clear pattern of up- or downregulation of metabolic pathways. In contrast, perinatal factors birth order, sex and mode of delivery affected several energy and biosynthetic pathways, including glutamate and aspartic acid—histidine metabolism (p = 0.004) and the tricarboxylic acid cycle (p = 0.006) for birth order; branched chain amino acid metabolism (p = 0.0009) and vitamin B₆ metabolism (p = 0.01) for sex; and glyoxylate and dicarboxylic acid metabolism (p = 0.005) for mode of delivery. Maternal diet was also related to some of the metabolites associated with allergy. In conclusion, the cord blood metabolome includes individual metabolites that reflect lifestyle, microbial and other factors that may be associated with future allergy diagnosis, and also reflects temporally close events/factors. Larger studies are required to confirm these associations, and perinatal factors such as birth order or siblings must be considered in future cord-blood metabolome studies.

Using Differential Threshold Effects of Individual and Combined Periconceptional Methyl Donor Status on Maternal Genomic LINE-1 and Imprinted H19 DNA Methylation to Predict Birth Weight Variance in the Taiwan Pregnancy-Newborn Epigenetics (TPNE) Cohort Study

BACKGROUND

Few studies have comprehensively examined the effect of methyl donor status on maternal DNA methylation and birth outcomes.

OBJECTIVES

This study examined associations between periconceptional methyl donor status and genome-wide and specific imprinted gene methylation and fetal growth indices in the Taiwan Pregnancy-Newborn Epigenetics cohort.

METHODS

Plasma folate, choline (free form), and betaine concentrations of the participants enrolled at 7-10 weeks of gestation were analyzed. DNA methylation at regulatory sequences of the imprinted H19 gene and genomic long interspersed nuclear element 1 (LINE-1) were measured in maternal lymphocytes using bisulfite/high-resolution melt polymerase chain reaction. Associations with birth weight (BW) were estimated through multiple regressions from 112 mother-newborn pairs.

RESULTS

A nonlinear "L-shaped" relation and an inverse association between maternal plasma folate in T1 (mean ± SE: 17.6 ± 5.1 nmol/L) and lymphocytic LINE-1 methylation (β: -0.49, P = 0.027) were characterized. After adjusting for LINE-1 methylation, individual maternal folate concentrations were positively associated with BW variance (β = 0.24, P = 0.035), and the association was more pronounced in mothers with choline in T1 (mean ± SE: 5.4 ± 0.6 μmol/L; β: 0.40, P = 0.039). Choline status of the mothers in T2 (mean ± SE: 7.2 ± 0.6 μmol/L) was inversely associated with LINE-1 methylation (β: -0.43, P = 0.035), and a positive association was evident between T1 choline and H19 methylation (β: 0.48, P = 0.011). After adjusting for epigenetic modification, maternal choline status predicted a positive association with BW (β: 0.56, P = 0.005), but the effect was limited to mothers with high betaine concentrations in T3 (mean ± SE: 36.4 ± 8.8 μmol/L), depending on folate status.

CONCLUSIONS

Our data highlight the differential threshold effects of periconceptional folate, choline, and betaine status on genomic LINE-1 and H19 DNA methylation and how their interplay has a long-term effect on BW variance.

Clinical influence of maternal serum homocysteine, folate and vitamin B12 in the development of pre-eclampsia

Background: The aim of this study was to investigate the correlation between maternal serum homocysteine (Hcy), folate, vitamin B12 (VitB12) and the development of pre-eclampsia (PE).

Methods: Seventy-eight normal pregnant women (without hypertension and proteinuria during their pregnancy (control group)), 66 cases of gestational hypertension (GH group) and 82 cases of pre-eclampsia (PE group, with 56 cases of mild disease and 26 cases of severe disease) were include in this study. The maternal serum Hcy, folate and VitB12 level of the included cases were examined between 11 to 13 weeks gestation and compared between each group.

Results: The serum levels of VitB12 were significantly different between the control, GH and PE groups (p<0.05). The serum levels of Hcy in the PE group were significantly higher than those of the control group (p<0.05). However, the serum levels of folate in the PE group were significantly lower than those of control group (p<0.05). Significant statistical differences in the maternal serum Hcy and folate were found between mild and severe PE patient groups (p<0.05). A significant correlation was found between maternal serum Hcy and VitB12 (r=-0.34, p=0.001).

Conclusion: Hcy, folate and VitB12 may play an important role in the development of PE and could be potential serological biomarkers for early PE diagnosis.

Prospective associations of maternal choline status with offspring body composition in the first 5 years of life in two large mother-offspring cohorts: the Southampton Women's Survey cohort and the Growing Up in Singapore Towards healthy Outcomes cohort

BACKGROUND

Choline status has been positively associated with weight and fat mass in animal and human studies. As evidence examining maternal circulating choline concentrations and offspring body composition in human infants/children is lacking, we investigated this in two cohorts.

METHODS

Maternal choline concentrations were measured in the UK Southampton Women's Survey (SWS; serum, n = 985, 11 weeks' gestation) and Singapore Growing Up Towards healthy Outcomes (GUSTO); n = 955, 26-28 weeks' gestation) mother-offspring cohorts. Offspring anthropometry was measured at birth and up to age 5 years. Body fat mass was determined using dual-energy x-ray absorptiometry at birth and age 4 years for SWS; and using air-displacement plethysmography at birth and age 5 years for GUSTO. Linear-regression analyses were performed, adjusting for confounders.

RESULTS

In SWS, higher maternal choline concentrations were associated with higher neonatal total body fat mass {β = 0.60 standard deviation [SD]/5 µmol/L maternal choline [95% confidence interval (CI) 0.04-1.16]} and higher subscapular skinfold thickness [β = 0.55 mm/5 µmol/L (95% CI, 0.12-1.00)] at birth. In GUSTO, higher maternal choline concentrations were associated with higher neonatal body mass index-for-age z-score [β = 0.31 SD/5 µmol/L (0.10-0.51)] and higher triceps [β = 0.38 mm/5 µmol/L (95% CI, 0.11-0.65)] and subscapular skinfold thicknesses [β = 0.26 mm/5 µmol/L (95% CI, 0.01-0.50)] at birth. No consistent trends were observed between maternal choline and offspring gain in body mass index, skinfold thicknesses, abdominal circumference, weight, length/height and adiposity measures in later infancy and early childhood.

CONCLUSION

Our study provides evidence that maternal circulating choline concentrations during pregnancy are positively associated with offspring BMI, skinfold thicknesses and adiposity at birth, but not with growth and adiposity through infancy and early childhood to the age of 5 years.

Higher maternal plasma folate, vitamin B12 and homocysteine levels in women with preeclampsia

Micronutrients like vitamin B₁₂ and folate play an important role in nucleic acid metabolism, cell growth, and are important determinants of fetal growth. The present study examined the levels of maternal and cord plasma folate, vitamin B₁₂, homocysteine, and their association with birth outcome in women with preeclampsia (PE). This study includes 450 normotensive control (NC) and 350 women with PE. PE women were further classified into women delivering at term (n = 224) and preterm (n = 126). Maternal and cord blood was collected at delivery. The levels of maternal vitamin B₁₂ (p < 0.05), folate (p < 0.01), and homocysteine (p < 0.01) were higher in the PE group as compared to the NC group. Maternal folate levels were higher in both term and preterm groups, while vitamin B₁₂ levels were higher only in the preterm group as compared to NC group. In contrast, homocysteine was higher only in the term PE group. Similar changes were also observed in the cord plasma. There was a positive association of maternal plasma homocysteine with systolic (r = 0.151, p = 0.000, n = 578) and diastolic blood pressure (r = 0.213, p = 0.000, n = 578) in the whole cohort. A negative association of maternal folate with systolic blood pressure (r = -0.105, p = 0.048, n = 352) while a positive association with baby weight in the NC group (r = 0.116, p = 0.029, n = 352). The present study suggests that maternal and cord micronutrient levels are altered in women with PE.

Applications of Metabolomics in the Study and Management of Preeclampsia; A Review of the Literature

Introduction

Preeclampsia represents a major public health burden worldwide, but predictive and diagnostic biomarkers are lacking. Metabolomics is emerging as a valuable approach to generating novel biomarkers whilst increasing the mechanistic understanding of this complex condition.

Objectives

To summarize the published literature on the use of metabolomics as a tool to study preeclampsia.

Methods

PubMed and Web of Science were searched for articles that performed metabolomic profiling of human biosamples using either Mass-spectrometry or Nuclear Magnetic Resonance based approaches and which included preeclampsia as a primary endpoint.

Results

Twenty-eight studies investigating the metabolome of preeclampsia in a variety of biospecimens were identified. Individual metabolite and metabolite profiles were reported to have discriminatory ability to distinguish preeclamptic from normal pregnancies, both prior to and post diagnosis. Lipids and carnitines were among the most commonly reported metabolites. Further work and validation studies are required to demonstrate the utility of such metabolites as preeclampsia biomarkers.

Conclusion

Metabolomic-based biomarkers of preeclampsia have yet to be integrated into routine clinical practice. However, metabolomic profiling is becoming increasingly popular in the study of preeclampsia and is likely to be a valuable tool to better understand the pathophysiology of this disorder and to better classify its subtypes, particularly when integrated with other omic data.

Human Placental Arterial Distensibility, Birth Weight, and Body Size Are Positively Related to Fetal Homocysteine Concentration

Methionine demethylation during metabolism generates homocysteine (Hcy) and its remethylation requires folate and cobalamin. Elevated Hcy concentrations are associated with vascular-related complications of pregnancy, including increased vascular stiffness, predictive of clinical vascular disease. Maternal and fetal total Hcy (tHcy) concentrations are positively related, yet the influence of Hcy on fetoplacental vascular function in normal pregnancy has not been examined. We hypothesized that Hcy alters fetoplacental vascular characteristics with influences on fetal growth outcomes. We investigated (1) placental chorionic plate artery distensibility and neonatal blood pressure in relation to umbilical plasma tHcy; (2) relationships between cord venous (CV) and cord arterial (CA) plasma tHcy, folate, and cobalamin concentrations; and (3) tHcy associations with birth weight and anthropometric measurements of body size as indices of fetal growth in normal pregnancies with appropriate weight-for-gestational age newborns. Maternal plasma tHcy, folate, and cobalamin concentrations were consistent with published data. Placental chorionic plate artery distensibility index (β; measure of vessel stiffness) was inversely related to CA tHcy, yet neonatal blood pressure was not significantly affected. CV and CA tHcy concentrations were positively related and CV tHcy negatively related to CV cobalamin but not folate. CV tHcy concentration positively related to birth weight, corrected birth weight percentile, length, head circumference, and mid-arm circumference of newborns. CV cobalamin was inversely related to fetal growth indices but not to folate concentration. Our study demonstrates a potential relationship between fetal tHcy and placental artery distensibility, placing clinical relevance to cobalamin in influencing Hcy concentration and maintaining low vascular resistance to facilitate nutrient exchange favorable to fetal growth.

Prospective associations of maternal betaine status with offspring weight and body composition at birth: the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort study

BACKGROUND

Betaine supplementation results in lower body weight and fat mass and higher lean mass in animals and adult humans. However, the relation between maternal betaine status and offspring birth weight and body composition is less known.

OBJECTIVE

The aim was to examine the association between maternal betaine status and neonatal birth size and adiposity in an Asian mother-offspring cohort.

DESIGN

We included 955 pregnant women whose plasma betaine concentrations were measured at 26-28 wk of gestation. Neonatal anthropometric values were measured at birth, and abdominal adipose tissue compartments were assessed by MRI in a subset of infants (n = 307) in the first 14 d after birth. Multivariate general linear models were used to adjust for gestational age; fetal sex; and maternal age, height, education, ethnicity, prepregnancy body mass index, and plasma folate, vitamin B-12, and choline concentrations.

RESULTS

The mean ± SD plasma concentration of betaine was 13.2 ± 2.7 μmol/L (range: 5.3-25.0 μmol/L). After adjustment for covariates, higher maternal plasma betaine was associated with lower birth weight (β: -57.6 g; 95% CI: -109.9, -5.3 g), shorter birth length (β: -0.29 cm per 5-μmol/L increment; 95% CI: -0.55, -0.03 cm), smaller head circumference (-0.20 cm; 95% CI: -0.38, -0.02 cm), smaller midupper arm circumference (-0.16 cm; 95% CI: -0.30, -0.03 cm), lower volumes of abdominal superficial subcutaneous adipose tissue (-4.53 mL; 95% CI: -8.70, -0.36 mL), and a higher risk of small-for-gestational-age birth (OR: 1.57; 95% CI: 1.05, 2.35).

CONCLUSIONS

Higher maternal betaine status was generally associated with smaller infant birth size and less abdominal fat mass. Further studies are needed to replicate these findings and to understand their biological mechanisms. This study was registered at clinicaltrials.gov as NCT01174875.

The association of single nucleotide polymorphisms of the maternal cystathionine-β-synthase gene with early-onset preeclampsia

OBJECTIVES

Preeclampsia (PE) is a pregnancy complication, characterized by hypertension and proteinuria. The transsulfuration pathway may be involved in its pathophysiology, since homocysteine, cystathionine and cysteine are increased in PE. Cystathionine-β-synthase (CBS) is a key-enzyme in the pathway, converting homocysteine into cysteine via cystathionine. Another product of CBS is hydrogen sulfide (H2S), a vasodilatory, proangiogenic and cytoprotective gas that is thought to play a role in placental and vascular function during pregnancy. Since single nucleotide polymorphisms (SNPs) can affect CBS expression and/or function, we studied tag-SNPs in the CBS gene in PE patients.

STUDY DESIGN

Controls (n=75), early-onset (n=45), and late-onset PE (n=52) cases were genotyped for six tag-SNPs in the CBS gene; rs12329764, rs2851391, rs234713, rs234706, rs1789953, and rs11203172. Plasma homocysteine, cysteine and cystathionine were determined during pregnancy.

MAIN OUTCOME MEASURES

Early-onset PE, late-onset PE.

RESULTS

Women with the minor allele of rs11203172 have a reduced risk for early-onset PE. Compared to women without the minor allele, normotensive pregnant women with the minor allele of rs11203172 and rs234713 have lower cysteine levels. Women with the minor allele of rs1789953 have increased levels of cysteine and cystathionine, compared to women without.

CONCLUSION

The CBS tag-SNP rs11203172 is associated with a decreased risk for early-onset PE. Decreased cysteine concentrations in normotensive pregnant women carrying the minor allele of rs11203172, may be due to increased cysteine conversion to H2S by CBS. Higher H2S levels may positively affect placentation and vascular function during pregnancy and decrease their risk for PE.

Increased homocysteine levels exist in women with preeclampsia from early pregnancy

OBJECTIVE

The present prospective study examines the levels of maternal plasma folate, vitamin B12 and homocysteine in normotensive control (NC) women and women with preeclampsia (PE) from early pregnancy till delivery.

METHODS

The present study includes 126 NC and 62 PE women. Maternal blood was collected at 3 time points during pregnancy (T1 = 16th-20th weeks, T2 = 26th-30th weeks and T3 = at delivery). Levels of folate, vitamin B12 and homocysteine were estimated by the chemiluminescent microparticle immunoassay technology.

RESULTS

Maternal plasma folate levels were similar between NC and PE women at all the time points across gestation. Maternal plasma vitamin B12 levels were significantly higher in PE (p < 0.05) as compared with NC at T2. Maternal plasma homocysteine levels were higher in PE as compared with NC at all the time points, i.e. T1, T2 (p < 0.05 for both) and T3 (p < 0.01).

CONCLUSION

Our results indicate that higher homocysteine levels exist in women with PE from early pregnancy and continue till delivery.

(1)H MRS: a potential biomarker of in utero placental function

The placenta is a temporary organ that is essential for a healthy pregnancy. It performs several important functions, including the transport of nutrients, the removal of waste products and the metabolism of certain substances. Placental disorders have been found to account for over 50% of stillbirths. Despite this, there are currently no methods available to directly and non-invasively assess placental function in utero. The primary aim of this pilot study was to investigate the use of (1)H MRS for this purpose. (1)H MRS offers the possibility to detect several placental metabolites, including choline, lipids and the amino acids glutamine and glutamate (Glx), which are vital to fetal development and placental function. Here, in utero placental spectra were acquired from nine small for gestational age (SGA) pregnancies, a cohort who are at increased risk of perinatal morbidity and mortality, and from nine healthy gestation-matched pregnancies. All subjects were between 26 and 39 weeks of gestation. Placenta Glx, choline and lipids at 1.3 and 0.9 ppm were quantified as amplitude ratios to that of intrinsic H2O. Wilcoxon signed rank tests indicated a significant difference in Glx/H2O (p = 0.024) between the two groups, but not in choline/H2O (p = 0.722) or in either lipid/H2O ratio (1.3 ppm, p = 0.813; 0.9 ppm, p = 0.058). This study has demonstrated that (1)H MRS has potential for the detection of placental metabolites in utero. This warrants further investigation as a tool for the monitoring of placental function.

Metabolomic biomarkers in serum and urine in women with preeclampsia

OBJECTIVE

To explore the potential of magnetic resonance (MR) metabolomics for study of preeclampsia, for improved phenotyping and elucidating potential clues to etiology and pathogenesis.

METHODS

Urine and serum samples from pregnant women with preeclampsia (n = 10), normal pregnancies (n = 10) and non-pregnant women (n = 10) matched by age and gestational age were analyzed with MR spectroscopy and subjected to multivariate analysis. Metabolites were then quantified and compared between groups.

RESULTS

Urine and serum samples revealed clear differences between women with preeclampsia and both control groups (normal pregnant and non-pregnant women). Nine urine metabolites were significantly different between preeclampsia and the normal pregnant group. Urine samples from women with early onset preeclampsia clustered together in the multivariate analysis. The preeclampsia serum spectra showed higher levels of low and very-low density lipoproteins and lower levels of high-density lipoproteins when compared to both non-pregnant and normal pregnant women.

CONCLUSION

The MR determined metabolic profiles in urine and serum from women with preeclampsia are clearly different from normal pregnant women. The observed differences represent a potential to examine mechanisms underlying different preeclampsia phenotypes in urine and serum samples in larger studies. In addition, similarities between preeclampsia and cardiovascular disease in metabolomics are demonstrated.

Umbilical choline and related methylamines betaine and dimethylglycine in relation to birth weight

BACKGROUND

Low birth weight (LBW) is associated with increased morbidity and mortality for the newborn and risk of chronic disease in adulthood. Choline plays an essential role in the integrity of cell membranes, methylation reactions, and memory development. We examined whether choline, betaine, and dimethylglycine (DMG) concentrations were associated with LBW in Dutch women.

METHODS

Blood was sampled from umbilical cords (UCs) at delivery in singleton pregnancies (n = 1,126). Maternal blood was sampled at 30-34 wk of gestational age (GA) (n = 366). We calculated birth weights standardized for GA and defined LBW as standardized birth weight ≤ 2,500 g.

RESULTS

Maternal concentrations were lower as compared with UC concentrations and were not associated with birth weight. UC choline and betaine were inversely associated with birth weight (β = -60 (-89, -31) and β = -65 (-94, -36), respectively), whereas UC DMG was positively associated with birth weight (β = 35 (6.1, 63)). Odds ratios for LBW were 4.12 (1.15, 14.78), 5.68 (1.24, 25.91), and 0.48 (0.09, 2.65) for the highest UC choline, betaine, and DMG quartiles, respectively, as compared with the lowest quartiles.

CONCLUSION

We observed an increased risk of LBW with increased umbilical choline and betaine in venous UC blood. These results might reflect a change in choline consumption or metabolism or a disturbed placental function.

FOLATE METABOLISM AND PREECLAMPSIA

Preeclampsia (PE) is a multisystem disorder of human pregnancy, affecting about 6% of all pregnancies worldwide, and is one of the leading causes of maternal and infant morbidity and mortality. Despite decades of research into the pathogenesis of this complex disease, the underlying mechanisms remain unclear. As a result, the options for prevention and management of PE are limited. In recent years, there has been a growing body of evidence suggesting that folate deficiency is associated with PE, and folic acid supplementation may reduce the risk of developing PE in certain populations. Folate contributes to cell division and growth, and folate metabolism is involved in a large number of physiological and pathophysiological processes in human development. Sufficient supply of folate is therefore particularly important during pregnancy. Nevertheless, the exact mechanisms of folic acid deficiency increasing the risk of developing PE are still unclear. This article reviews what is understood about the aetiology of PE and the relationship between folate metabolism and PE so as to enhance further discussions on the subject.

Epigenetics and microRNAs in preeclampsia

Strong evidence suggests a potential link among epigenetics, microRNAs (miRNAs), and pregnancy complications. Much research still needs to be carried out to determine whether epigenetic factors are predictive in the pathogenesis of preeclampsia (PE), a life-threatening disease during pregnancy. Recently, the importance of maternal epigenetic features, including DNA methylation, histone modifications, epigenetically regulated miRNA, and the effect of imprinted or non-imprinted genes on trophoblast growth, invasion, as well as fetal development and hypertension in pregnancy, has been demonstrated in a series of articles. This article discusses the current evidence of this complicated network of miRNA and epigenetic factors as potential mechanisms that may underlie the theories of disease for PE. Translating these basic epigenetic findings to clinical practice could potentially serve as prognostic biomarkers for diagnosis in its early stages and could help in the development of prophylactic strategies.

Maternal homocysteine and small-for-gestational-age offspring: systematic review and meta-analysis

BACKGROUND

Growth retardation in utero leading to small-for-gestational-age (SGA) newborns is associated with increased neonatal morbidity and mortality and with lifelong consequences such as poor cognitive function and cardiovascular diseases. Maternal total homocysteine (tHcy) concentrations have been linked to a wide range of adverse pregnancy outcomes and could possibly influence birth weight.

OBJECTIVE

We performed a systematic review of and meta-analysis on the association of maternal tHcy and birth weight.

DESIGN

A literature search of English, German, and French publications with the use of the PubMed database (January 1966-July 2010) found 78 abstracts. Search terms were as follows: homocysteine AND (birth weight OR small for gestational age OR intrauterine growth retardation). Studies were eligible if information on maternal tHcy and birth weight and the possible association between maternal tHcy and birth weight was available. Effect size estimates were converted to ORs as estimates of the RR of a woman to deliver SGA offspring when maternal tHcy exceeded the 90th percentile.

RESULTS

The search yielded 19 studies for analysis, consisting of 21,326 individuals. Pooled analysis resulted in a crude OR of 1.25 (95% CI: 1.09, 1.44). When this estimate was expressed as a linear effect, it corresponded to a decrease in birth weight of 31 g (95% CI: -13, -51 g) for a 1-SD increase in maternal tHcy.

CONCLUSIONS

Higher maternal tHcy concentrations are associated with a small increased risk for SGA offspring. The small estimated birth weight difference might be of little clinical relevance for the individual newborn; however, it could be of greater importance at a population level.

Congenital heart defects and biomarkers of methylation in children: a case-control study

BACKGROUND

Derangements in the maternal methylation pathway, expressed by global hypomethylation and hyperhomocysteinemia, are associated with the risk of having a child with a congenital heart defect (CHD). It is not known whether periconception exposure to these metabolic derangements contributes to chromosome segregation and metabolic programming of this pathway in the foetus.

DESIGN

In a Dutch population-based case-control study of 143 children with CHD and 186 healthy children, we investigated S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), total homocysteine (tHcy), the vitamins folate and B12 and the functional single nucleotide polymorphisms in the folate gene MTHFR 677C>T and 1298A>C. Comparisons were made between cases and controls adjusting for age, medication, vitamin use and CHD family history.

RESULTS

In the overall CHD group, the median concentrations of SAM (P = 0·011), folate in serum (P = 0·021) and RBC (P = 0·030) were significantly higher than in the controls. Subgroup analysis showed that this was mainly attributable to complex CHD with higher SAM (P < 0·001), SAH (P = 0·012) and serum folate (P = 0·010) independent of carriership of MTHFR polymorphisms. Highest concentrations of SAM, SAH and folate RBC were observed in complex syndromic CHD. The subgroup of children with Down syndrome, however, showed significantly higher SAH (P = 0·037) and significantly lower SAM:SAH ratio (P = 0·034) compared with other complex CHD, suggesting a state of global hypomethylation.

CONCLUSION

High concentrations of methylation biomarkers in very young children are associated with complex CHD. Down syndrome and CHD may be associated with a global hypomethylation status, which has to be confirmed in tissues and global DNA methylation in future studies.

Choline and betaine in health and disease

Choline is an essential nutrient, but is also formed by de novo synthesis. Choline and its derivatives serve as components of structural lipoproteins, blood and membrane lipids, and as a precursor of the neurotransmitter acetylcholine. Pre-and postnatal choline availability is important for neurodevelopment in rodents. Choline is oxidized to betaine that serves as an osmoregulator and is a substrate in the betaine-homocysteine methyltransferase reaction, which links choline and betaine to the folate-dependent one-carbon metabolism. Choline and betaine are important sources of one-carbon units, in particular, during folate deficiency. Choline or betaine supplementation in humans reduces concentration of total homocysteine (tHcy), and plasma betaine is a strong predictor of plasma tHcy in individuals with low plasma concentration of folate and other B vitamins (B₂, B₆, and B₁₂) in combination TT genotype of the methylenetetrahydrofolate reductase 677 C->T polymorphism. The link to one-carbon metabolism and the recent availability of food composition data have motivated studies on choline and betaine as risk factors of chronic diseases previously studied in relation to folate and homocysteine status. High intake and plasma level of choline in the mother seems to afford reduced risk of neural tube defects. Intake of choline and betaine shows no consistent relation to cancer or cardiovascular risk or risk factors, whereas an unfavorable cardiovascular risk factor profile was associated with high choline and low betaine concentrations in plasma. Thus, choline and betaine showed opposite relations with key components of metabolic syndrome, suggesting a disruption of mitochondrial choline oxidation to betaine as part of the mitochondrial dysfunction in metabolic syndrome.

Homocysteine in pregnancy

The aim of this review is to evaluate the evidence for and against fasting plasma total homocysteine (tHcy) as a biomarker/risk factor of impaired reproductive function before and during pregnancy. Apart from nutritional and lifestyle factors, tHcy is also influenced by physiological factors specific to pregnancy such as hemodilution, increased glomerular filtration rate, and endocrinological changes. These lead to a considerable reduction under normal circumstances in tHcy by midpregnancy. Stimulating excess endogenous homocysteine production before and during pregnancy in animal experiments and adding exogenous homocysteine to cell cultures result in the impairment of reproductive and developmental processes from preconception throughout pregnancy and during subsequent development of the offspring. Different studies have confirmed that elevated tHcy is a risk factor for subfertility, congenital developmental defects, preeclampsia, and intrauterine growth retardation. There is conflicting evidence that elevated tHcy is a risk factor for miscarriage, gestational diabetes, premature rupture of the membranes, placental abruption, and offspring with Down syndrome. Prospective, sufficiently powered, studies from preconception/early pregnancy are required to determine whether tHcy is a risk factor for these pregnancy complications.

Promoter hypomethylation of COMT in human placenta is not associated with the development of pre-eclampsia

Disruption of the Catechol-O-methyltransferase (COMT) gene has been shown to be involved in pre-eclampsia (PE). To investigate whether two promoters of the COMT gene are differentially regulated by methylation in PE patients, we have analyzed the genomic DNA extracted from placenta (cases n = 16; controls n = 21), maternal peripheral blood (cases n = 4; controls n = 6) and umbilical cord blood (cases n = 8; controls n = 8) of women with PE and women with normal pregnancy. Bisulfite sequencing identified the predominantly unmethylated MB-COMT promoter in placenta, maternal peripheral blood and umbilical cord blood samples (PE and control). Subsequent quantitative MassArray data confirmed a significant tissue-specific hypomethylation of the S-COMT promoter in placenta (mean = 28.6%) when compared with its densely methylated patterns in blood samples (mean = 74.5%, P < 0.001), consistent with the sequencing data. However, no PE-specific methylation difference was found between cases and controls either in placenta or in blood samples. Moreover, none of the clinical characteristics had an effect on the methylation status of the S-COMT promoter. This study does not support a causal link between methylation regulation of COMT promoters and PE. However, the observed placenta-specific S-COMT promoter may be a potential marker for early prediction of PE in maternal plasma, although this remains to be further evaluated.

Homocysteine, folic acid and vitamin B12 levels in maternal and umbilical cord plasma and homocysteine levels in placenta in pregnant women with pre-eclampsia

AIM

The aim of this study was to evaluate maternal and fetal serum levels of homocysteine, folic acid, vitamin B12 and placental tissue levels of homocysteine and their association with severity of pre-eclampsia.

MATERIAL & METHODS

A case-control study, performed by a single center, included 26 pregnant women with mild pre-eclampsia, 26 pregnant women with severe pre-eclampsia and 26 healthy pregnant women. Maternal blood was collected before delivery and fetal blood was collected from the umbilical cord at delivery. Placental tissue samples were obtained after delivery of placenta. Homocysteine, folic acid, vitamin B12 levels in serum and homocysteine levels in placental tissue homogenates were analyzed by immunochemiluminescent assay.

RESULTS

Homocysteine levels in both maternal and fetal serum were significantly higher in the severe pre-eclampsia group compared to mild pre-eclampsia and control groups. However, homocysteine levels in both maternal and fetal serum were not significantly different between mild pre-eclampsia and control groups. No significant differences were observed in folic acid and vitamin B12 levels in both maternal and fetal serum between the groups. Homocysteine levels in placental tissue homogenates were too low to be measured in the three groups (<2 µmol/l).

CONCLUSION

Maternal and fetal serum homocysteine levels were found to be significantly higher in severe pre-eclampsia group compared to mild pre-eclampsia and control groups suggesting that elevated serum levels of homocysteine might be associated with severity of pre-eclampsia. On the other hand it seems like elevated serum homocysteine levels were not associated with deficiency of folic acid and vitamin B12.

Critical issues in setting micronutrient recommendations for pregnant women: an insight

The European Micronutrient Recommendations Aligned (EURRECA) Network aims to provide standardized approaches to reveal and beneficially influence variability within the European Union in micronutrient recommendations for vulnerable population groups. Characterization of the 'vulnerability' together with the 'variability' of micronutrient needs represents the first step to creating guidelines for setting micronutrient recommendations within target populations. This paper describes some of the key factors and characteristics relevant to assess micronutrient requirements and formulate recommendations of micronutrients in pregnancy. Nutritional requirements during pregnancy increase to support fetal growth and development as well as maternal metabolism and tissue accretion. Micronutrients are involved in both embryonal and fetal organ development and overall pregnancy outcomes. Several factors may affect directly or indirectly fetal nourishment and the overall pregnancy outcomes, such as the quality of diet including intakes and bioavailability of micronutrients, maternal age, and the overall environment. The bioavailability of micronutrients during pregnancy varies depending on specific metabolic mechanisms because pregnancy is an anabolic and dynamic state orchestrated via hormones acting for both redirection of nutrients to highly specialized maternal tissues and transfer of nutrients to the developing fetus. The timing of prenatal intakes or supplementations of specific micronutrients is also crucial as pregnancy is characterized by different stages that represent a continuum, up to lactation and beyond. Consequently, nutrition during pregnancy might have long-lasting effects on the well-being of the mother and the fetus, and may further influence the health of the baby at a later age.

Pre-eclampsia: connecting angiogenic and metabolic pathways

Pre-eclampsia is a hypertensive disease of pregnancy with a worldwide incidence of 5-8%. This review focuses on recent developments in pre-eclampsia research related to angiogenesis and metabolism. We first address the 'angiogenic imbalance' theory, which hypothesizes that pre-eclampsia results from an imbalance of factors that promote or antagonize angiogenesis, such as soluble fms-like tyrosine kinase (sFlt1), 2-methoxyestradiol (2-ME) and catechol-O-methyltransferase (COMT). Next, we analyze the association between pre-eclampsia and dysfunctional metabolism of both homocysteine and placental glycogen. We hope that illuminating some of the various connections existing between angiogenesis and metabolism in pre-eclampsia will facilitate the update or reconsideration of old models of pathogenesis.

Maternal homocysteine and related B vitamins as risk factors for low birthweight

OBJECTIVE

We designed a large prospective study to explore the relationship between maternal homocysteine concentrations and related B vitamins and birthweight.

STUDY DESIGN

Blood was sampled from pregnant women at 30-34 weeks of gestation and their newborn infants (n = 366).

RESULTS

Concentrations of all analytes were higher in umbilical cord compared with maternal samples. Birthweight was related negatively to maternal homocysteine (r = -0.12) but not related to maternal cobalamin, methylmalonic acid, and folate (r = 0.02, r = 0.06, and r = 0.04, respectively). Regression analysis revealed smoking (beta = -313; 95% confidence interval [CI], -479 to -149), gestational age (beta = 150; 95% CI, 118-182), female sex (beta = -146; 95% CI, -256 to -35), and parity (beta = 104; 95% CI, 37-171) as strong determinants of birthweight. Maternal homocysteine, cobalamin, methylmalonic acid, and folate were not determinants of birthweight in multivariate analysis.

CONCLUSION

Maternal homocysteine and B vitamins are not related to birthweight in a multivariate model that was adjusted for potential confounders.

Asymmetric dimethylarginine in the maternal and fetal circulation in preeclampsia

Preeclampsia is a leading cause of intrauterine growth restriction and preterm birth. Endothelial dysfunction is the common final pathway leading to clinical signs of preeclampsia including hypertension and proteinuria. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NOS and induces endothelial dysfunction by reversibly inhibiting NO production from l-arginine. The purpose of this study was to investigate maternal and fetal concentrations of ADMA, l-arginine, and symmetric dimethylarginine (SDMA). Women with preeclampsia (n = 47) and controls (n = 51) who gave birth by cesarean section were included in the study. We analyzed the maternal plasma and umbilical vein and artery plasma. We found that not only maternal concentrations of ADMA and SDMA but also l-arginine were significantly higher in women with preeclampsia than in controls. In fetal samples, only SDMA concentrations were higher in the preeclampsia group than in controls. The median ADMA concentration was three times higher in the fetal circulation than in the maternal circulation, but there was no difference between the preeclampsia group and the control group, and the veno-arterious gradient indicated that the placenta was the source of ADMA.

Effects of arsenic on maternal and fetal health

Arsenic, which is commonly found in drinking water, is a potent toxicant, but little is known about its effects on maternal health. Arsenic's modes of action include enzyme inhibition and oxidative stress as well as immune, endocrine, and epigenetic effects. A couple of studies reported increased blood pressure and anemia during pregnancy. Susceptibility to arsenic is dependent on the biomethylation, which occurs via one-carbon metabolism. Methylarsonic acid and dimethylarsinic acid are main metabolites in urine, and elevated methylarsonic acid is considered a general risk factor. Arsenic easily passes the placenta, and a few human studies indicate a moderately increased risk of impaired fetal growth and increased fetal and infant mortality. The fetus and infant are probably partly protected by the increased methylation of arsenic during pregnancy and lactation; the infant is also protected by low arsenic excretion in breast milk. Early-life exposure may induce changes that will become apparent much later in life.

Redox modulation of Ca2+ signaling in human endothelial and smooth muscle cells in pre-eclampsia

Pre-eclampsia (PE) is a leading cause of maternal hypertension in pregnancy and is associated with fetal growth restriction, premature birth, and fetal and maternal mortality. Activation and dysfunction of the maternal and fetal endothelium in PE appears to be a consequence of increased oxidative stress, resulting from elevated levels of circulating lipid peroxides. Accumulating evidence implicates reactive oxygen species (ROS) in the pathogenesis of vascular dysfunction in PE, perhaps involving a disturbance in intracellular Ca(2+) signaling. Several ion-transport pathways are highly sensitive to oxidative stress, and the resulting modulation of ion transport by ROS will affect intracellular Ca(2+) homeostasis. We review the evidence that changes in ion transport induced by ROS may be linked with abnormalities in Ca(2+)-mediated signal transduction, leading to endothelial and smooth muscle dysfunction in maternal and fetal circulations in PE. As dysregulation of Ca(2+) signaling in fetal umbilical endothelial cells is maintained in culture and embryonic, fetal, and postnatal development is affected by the cellular redox state, we hypothesize that impaired redox signaling in PE may influence "programming" of the fetal cardiovascular system and endothelial function in adulthood.