Elevated circulating homocyst(e)ine levels in placental vascular disease and associated pre-eclampsia

Association between early spontaneous abortion and homocysteine metabolism

Objective

The purpose of this study is to explore the effects of homocysteine (HCY) metabolism and related factors on early spontaneous abortion.

Methods

We conducted a hospital-based case-control study and included a total of 500 cases and 1,000 controls in Shaanxi China. Pregnant women waiting for delivery in the hospital were interviewed to report their characteristics and other relevant information during pregnancy. The unconditional Logisitic regression model was applied to assess the association between early spontaneous abortion and HCY metabolism and related factors. The multiplicative model was applied to assess the effects of interaction of HCY metabolism and related factors on early spontaneous abortion. The logit test method of generalized structural equation model (GSEM) was used to construct the pathway diagram of HCY metabolism and related factors affecting early spontaneous abortion.

Results

Folic acid supplementation and adequate folic acid supplementation during periconception were the protective factors of early spontaneous abortion (OR = 0.50, 95% CI: 0.38-0.65; OR = 0.44, 95% CI: 0.35-0.54). The serum folate deficiency, higher plasma HCY in early pregnancy, the women who carried the MTHFR 677TT genotype were the risk factors of early spontaneous abortion (OR = 5.87, 95% CI: 1.53-22.50; OR = 2.94, 95% CI: 1.14-7.57; OR = 2.32, 95% CI: 1.20-4.50). The women's educational level and maternal and child health care utilization affected the occurrence of early spontaneous abortion by influencing the folic acid supplementation during periconception. The folic acid supplementation during periconception affected the occurrence of early spontaneous abortion by influencing the level of serum folate or plasma HCY in early pregnancy. The maternal MTHFR 677 gene polymorphism affected the occurrence of early spontaneous abortion by influencing the level of serum folate in early pregnancy. In terms of the risks for early spontaneous abortion, there was multiplicative interaction between higher plasma HCY in early pregnancy, serum folate deficiency in early pregnancy and maternal MTHFR 677TT genotype (OR = 1.76, 95% CI: 1.17-4.03), and there was multiplicative interaction between higher plasma HCY and serum folate deficiency in early pregnancy (OR = 3.46, 95% CI: 2.49-4.81), and there was multiplicative interaction between serum folate deficiency in early pregnancy and maternal MTHFR 677TT genotype (OR = 3.50, 95% CI: 2.78-5.18). The above interactions are all synergistic. The occurrence risk of early spontaneous abortion was significantly increased if multiple factors existed at the same time.

Conclusion

Our study is the first time to construct the pathway of HCY metabolism and related factors affecting early spontaneous abortion, and provides a comprehensively new idea to prevent and reduce the occurrence of spontaneous abortion.

Is Maternal Serum Homocysteine a Novel Diagnostic Biomarker for Predicting Placenta-Mediated Disorders?

Background Uteroplacental insufficiency and related disorders, though a significant cause of undesirable maternal and fetal outcomes, are complex and poorly understood. The newer screening modalities are expensive and difficult to procure for day-to-day use in developing countries. This study aimed to examine the association of mid-trimester maternal serum homocysteine levels with maternal and neonatal outcomes. Methodology This was a prospective cohort study involving 100 participants between 18 and 28 weeks of gestation. The study was conducted at a tertiary care center in south India from July 2019 to September 2020. Maternal blood samples were analyzed for serum homocysteine levels and correlated with the third-trimester pregnancy outcomes. Statistical analysis was done, and diagnostic measures were computed. Results The mean age was found to be 26.8 ± 4.8 years. Of the participants, 15% (n = 15) were diagnosed with hypertensive disorders during pregnancy, while 7% (n = 7) had fetal growth restriction (FGR) and 7% (n = 7) were complicated by preterm birth. An elevated maternal serum homocysteine level was positively associated with adverse pregnancy outcome measures such as hypertensive disorders (p = 0.001), with sensitivity and specificity of 27% and 99%, respectively, and FGR (p = 0.03) with sensitivity and specificity of 28.6% and 98.6%, respectively. Moreover, a statistically significant outcome was noted with preterm birth before 37 weeks (p = 0.001) and a low Apgar score (p = 0.02). No association was established with spontaneous preterm labor (p = 1.00), neonatal birth weight (p = 0.42), and special care unit admission (p = 1.00). Conclusions Such a simple and affordable investigation has the potential to go a long way in the early diagnosis and management of placenta-mediated disorders in pregnancy during the antenatal period, especially in low-resource settings.

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.

Is Supplementation with Micronutrients Still Necessary during Pregnancy? A Review

INTRODUCTION

Proper nutrition during pregnancy is important to prevent nutritional imbalances that interfere with pregnancy. Micronutrients play critical roles in embryogenesis, fetal growth, and maternal health, as energy, protein, vitamin, and mineral needs can increase during pregnancy. Increased needs can be met by increasing the intake of dietary micronutrients. Severe micronutrient deficiency or excess during pregnancy can have negative effects on fetal growth (intrauterine growth retardation, low birth weight, or congenital malformations) and pregnancy development (pre-eclampsia or gestational diabetes). We investigate whether it is necessary to continue micronutrient supplementation during pregnancy to improve women's health in this stage and whether this supplementation could prevent and control pathologies associated with pregnancy.

AIM

The present review aims to summarize evidence on the effects of nutritional deficiencies on maternal and newborn morbidity.

METHODS

This aim is addressed by critically reviewing results from published studies on supplementation with different nutrients during pregnancy. For this, major scientific databases, scientific texts, and official webpages have been consulted. PubMed searches using the terms "pregnancy" OR "maternal-fetal health" AND "vitamins" OR "minerals" OR "supplementation" AND "requirement" OR "deficiency nutrients" were performed.

RESULTS

There are accepted interventions during pregnancy, such as folic acid supplementation to prevent congenital neural tube defects, potassium iodide supplementation to correct neurodevelopment, and oral iron supplementation during the second half of pregnancy to reduce the risk of maternal anemia and iron deficiency. A number of micronutrients have also been associated with pre-eclampsia, gestational diabetes mellitus, and nausea and vomiting in pregnancy. In general, experimental studies are necessary to demonstrate the benefits of supplementation with different micronutrients and to adjust the recommended daily doses and the recommended periconceptional nutrition for mothers.

CONCLUSIONS

Presently, there is evidence of the benefits of micronutrient supplementation in perinatal results, but indiscriminate use is discouraged due to the fact that the side effects of excessive doses are not known. Evidence supports the idea that micronutrient deficiencies negatively affect maternal health and the outcome of pregnancy. No single micronutrient is responsible for the adverse effects; thus, supplementing or correcting one deficiency will not be very effective while other deficiencies exist.

Association of Elevated Cord Blood Oxidative Stress Biomarkers with Neonatal Outcomes in Mothers with Pre-Eclampsia: A Case-Control Study

OBJECTIVES

The objective of this study was to determine the relationship between the levels of stress biomarkers in cord blood and pre-eclampsia (PE) in a hospital-based population of pregnant patients and evaluate the effects on pregnancy outcomes.

DESIGN

This was an observational, case-control study. Participants/Materials, Setting, Methods: This case-control study included 282 patients with severe PE and 534 women with normal pregnancy. The umbilical cord was collected at delivery and tested for malonaldehyde (MDA), reactive oxygen species (ROS), superoxide dismutase, and homocysteine (Hcy) analysis. We performed a univariate general linear regression model analysis to control potential confounders and determined the underlying influencing factors for high MDA and ROS. A receiver operating characteristic curve analysis was conducted to determine the cutoff values for identifying severe PE. Further, the severe PE group was divided into the low- or high-MDA and low- or high-ROS subgroups according to the cutoff values. Finally, we created logistic regression models to estimate the adjusted odds ratio for each perinatal outcome in the high-MDA and high-ROS subgroup.

RESULTS

The levels of MDA and ROS levels were higher in women with severe PE than in normotensive pregnant patients. However, when adjusted for cord blood Hcy levels, the difference was insignificant. Additionally, both MDA (r = 0.359, p < 0.001) and ROS (r = 0.473, p < 0.001) were positively correlated with the cord blood Hcy level. The areas under the curve of MDA and ROS levels were 0.65 (95% confidence interval [CI]: 0.60-0.69) and 0.88 (95% CI: 0.86-0.90), respectively. Higher MDA and ROS levels were associated with increased risks of a low Apgar score, admission to the NICU, and assisted ventilation for the newborn.

LIMITATIONS

The study design led to the exclusion of several participants.

CONCLUSIONS

Increased levels of oxidative stress markers in the cord blood might be significantly associated with negative effects on newborns. High levels of Hcy in the cord blood might be associated with elevated MDA and ROS concentrations in women with severe PE.

MTHFR 1298A>C Substitution is a Strong Candidate for Analysis in Recurrent Pregnancy Loss: Evidence from 14,289 Subjects

We undertook meta-analyses on MTHFR 1298A>C substitution for critically evaluating its association with recurrent pregnancy loss (RPL). MTHFR genotype data for 5888 cases and 8401 controls from 39 studies were pooled to perform this meta-analyses. Genotype data were screened, scrutinized, pooled, analysed and subjected to sensitivity analysis to carefully evaluate the association between MTHFR 1298A>C and recurrent pregnancy loss. Genetic associations were sought using dominant, recessive and co-dominant models of genetic testing with odds ratio and 95% Confidence interval (CI) as the effect measures. Further analyses were undertaken by classifying the studies into Caucasian and East Asian sub-groups. Genetic heterogeneity was tested before pooling the data across studies. For assessing publication bias, Egger's intercept test was undertaken. We found a significant association of 1298A>C substitution with increased risk of RPL in the dominant (P=0.000; OR = 1.58; 95% CI =1.25-1.99) as well as recessive (P=0.000; OR = 1.66; 95% CI =1.25-2.20) models. In sub-group analysis, we observed a significant association of the polymorphism with RPL in the Caucasian populations using dominant (P=0.000; OR = 1.98; 95% CI =1.42-2.76) and recessive (P=0.000; OR = 2.20; 95% CI =1.49-3.24) models. However, this substitution showed no association with RPL in the East Asian populations (P=0.149; OR = 1.187; 95% CI =0.94-1.50). MTHFR 1298A>C substitution shows association with the risk of recurrent pregnancy loss. The association is in a population-specific manner with the substitution being a strong risk factor only in the Caucasian populations.

Association of MTHFR C677T Polymorphism with Preeclampsia in North East of Iran (Khorasan Province)

Background: Preeclampsia (PE) is one of the main causes of fetal and maternal mortality. The analysis of candidate gene polymorphisms can improve our understanding of the mechanisms underlying pathogenesis of PE. Present study is aimed at investigating the association between MTRR c.66A > G, MTHFR c.677C > T, MTHFR c.1298A > C, and MTR c.2756A > G polymorphisms and PE in Iranian women. Methods: About 117 women with history of PE and 103 healthy women with a pregnancy not complicated by PE were selected. The genomic DNA was extracted from peripheral blood. Single-nucleotide polymorphisms were genotyped using Real-Time PCR. Results: There was a significant difference between MTHFR c.677C > T polymorphism with PE (p = 0.045). The frequency of C/T heterozygous genotypes were (58% vs. 36%) in the case and control groups, respectively. There were no statistically significant differences between other genetic polymorphisms. Conclusions: The results indicated that the MTHFR c.677C > T polymorphism may be associated with development of PE in Iranian women.

Potential role of folate in pre-eclampsia

Dietary deficiencies of folate and other B vitamin cofactors involved in one-carbon metabolism, together with genetic polymorphisms in key folate-methionine metabolic pathway enzymes, are associated with increases in circulating plasma homocysteine, reduction in DNA methylation patterns, and genome instability events. All of these biomarkers have also been associated with pre-eclampsia. The aim of this review was to explore the literature and identify potential knowledge gaps in relation to the role of folate at the genomic level in either the etiology or the prevention of pre-eclampsia. A systematic search strategy was designed to identify citations in electronic databases for the following terms: folic acid supplementation AND pre-eclampsia, folic acid supplementation AND genome stability, folate AND genome stability AND pre-eclampsia, folic acid supplementation AND DNA methylation, and folate AND DNA methylation AND pre-eclampsia. Forty-three articles were selected according to predefined selection criteria. The studies included in the present review were not homogeneous, which made pooled analysis of the data very difficult. The present review highlights associations between folate deficiency and certain biomarkers observed in various tissues of women at risk of pre-eclampsia. Further investigation is required to understand the role of folate in either the etiology or the prevention of pre-eclampsia.

Folic acid supplementation and dietary folate intake, and risk of preeclampsia

BACKGROUND/OBJECTIVES

Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia.

SUBJECTS/METHODS

A birth cohort study was conducted in 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10,041 pregnant women without chronic hypertension or gestational hypertension were enrolled.

RESULTS

Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43-0.87). A significant dose-response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30-0.81) and late-onset (OR=0.60, 95% CI: 0.42-0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31-0.87, for the highest quartile of dietary folate intake compared with the lowest).

CONCLUSIONS

Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.

Reduced syncytin-1 expression in choriocarcinoma BeWo cells activates the calpain1-AIF-mediated apoptosis, implication for preeclampsia

Placentas associated with preeclampsia are characterized by extensive apoptosis in trophoblast lineages. Syncytin-1 (HERVWE1) mediates the fusion of cytotrophoblasts to form syncytiotrophoblasts, which assume the placental barrier, fetal-maternal exchange and endocrine functions. While decreased syncytin-1 expression has been observed in preeclamptic placentas, it is not clear if this alteration is involved in trophoblast apoptosis. In the current study, we found that siRNA-mediated knockdown of syncytin-1 led to apoptosis in choriocarcinoma BeWo, a cell line of trophoblastic origin. Characterization of the apoptotic pathways indicated that this effect does not rely on the activation of caspases. Rather, decreased syncytin-1 levels activated the apoptosis inducing factor (AIF) apoptotic pathway by inducing the expression, cleavage, and nuclear translocation of AIF. Moreover, calpain1, the cysteine protease capable of cleaving AIF, was upregulated by syncytin-1 knockdown. Furthermore, treatment with calpain1 inhibitor MDL28170 effectively reversed AIF cleavage, AIF nuclear translocation, and cell apoptosis triggered by syncytin-1 downregulation, verifying the specific action of calpain1-AIF pathway in trophoblast apoptosis. We confirmed that preeclamptic placentas express lower levels of syncytin-1 than normal placentas, and observed an inverse correlation between syncytin-1 and AIF/calpain1 mRNA levels, a result consistent with the in vitro findings. Immunohistochemistry analyses indicated decreased syncytin-1 and increased AIF and calpain1 protein levels in apoptotic cells of preeclamptic placentas. These findings have for the first time revealed that decreased levels of syncytin-1 can trigger the AIF-mediated apoptosis pathway in BeWo cells. This novel mechanism may contribute to the structural and functional deficiencies of syncytium frequently observed in preeclamptic placentas.

Hydrogen sulfide deactivates common nitrobenzofurazan-based fluorescent thiol labeling reagents

Sulfhydryl-containing compounds, including thiols and hydrogen sulfide (H2S), play important but differential roles in biological structure and function. One major challenge in separating the biological roles of thiols and H2S is developing tools to effectively separate the reactivity of these sulfhydryl-containing compounds. To address this challenge, we report the differential responses of common electrophilic fluorescent thiol labeling reagents, including nitrobenzofurazan-based scaffolds, maleimides, alkylating agents, and electrophilic aldehydes, toward cysteine and H2S. Although H2S reacted with all of the investigated scaffolds, the photophysical response to each scaffold was significantly different. Maleimide-based, alkylating, and aldehydic thiol labeling reagents provided a diminished fluorescence response when treated with H2S. By contrast, nitrobenzofurazan-based labeling reagents were deactivated by H2S addition. Furthermore, the addition of H2S to thiol-activated nitrobenzofurazan-based reagents reduced the fluorescence signal, thus establishing the incompatibility of nitrobenzofurazan-based thiol labeling reagents in the presence of H2S. Taken together, these studies highlight the differential reactivity of thiols and H2S toward common thiol-labeling reagents and suggest that sufficient care must be taken when labeling or measuring thiols in cellular environments that produce H2S due to the potential for both false-positive and eroded responses.

Preventive effects of folic acid supplementation on adverse maternal and fetal outcomes

Although there is accumulating evidence regarding the additional protective effect of folic acid against adverse pregnancy outcomes other than neural tube defects, these effects have not been elucidated in detail. We evaluated whether folic acid supplementation is associated with favorable maternal and fetal outcomes. This was a secondary analysis of 215 pregnant women who were enrolled in our prior study. With additional data from telephone interviews regarding prenatal folic acid supplementation, existing demographic, maternal and fetal data were statistically analyzed. The concentration of folic acid in maternal blood was significantly higher following folic acid supplementation (24.6 ng/mL vs.11.8 ng/mL). In contrast, homocysteine level in maternal blood decreased with folic acid supplementation (5.5 µmol/mL vs. 6.8 µmol/mL). The rates of both preeclampsia (odds ratio [OR], 0.27; 95% confidence interval [CI], 0.09–0.76) and small for gestational age (SGA; 9.2% vs. 20.0%; OR, 0.42; 95% CI, 0.18–0.99) were lower in the folic acid supplementation group than those in the control group. Other pregnancy outcomes had no association with folic acid supplementation. The findings indicate that folic acid supplementation may help to prevent preeclampsia and SGA. Further studies are warranted to elucidate the favorable effects of folic acid supplementation on pregnancy outcomes.

Levels of key enzymes of methionine-homocysteine metabolism in preeclampsia

OBJECTIVE

To evaluate the role of key enzymes in the methionine-homocysteine metabolism (MHM) in the physiopathology of preeclampsia (PE).

METHODS

Plasma and placenta from pregnant women (32 controls and 16 PE patients) were analyzed after informed consent. Protein was quantified by western blot. RNA was obtained with RNA purification kit and was quantified by reverse transcritase followed by real-time PCR (RT-qPCR). Identification of the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) single-nucleotide polymorphisms (SNPs) and A2756G methionine synthase (MTR) SNP was performed using PCR followed by a high-resolution melting (HRM) analysis. S-adenosyl methionine (SAM) and S-adenosyl homocysteine (SAH) were measured in plasma using high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS). The SNP association analysis was carried out using Fisher's exact test. Statistical analysis was performed using a Mann-Whitney test.

RESULTS

RNA expression of MTHFR and MTR was significantly higher in patients with PE as compared with controls. Protein, SAM, and SAH levels showed no significant difference between preeclamptic patients and controls. No statistical differences between controls and PE patients were observed with the different SNPs studied.

CONCLUSION

The RNA expression of MTHFR and MTR is elevated in placentas of PE patients, highlighting a potential compensation mechanism of the methionine-homocysteine metabolism in the physiopathology of this disease.

A comparison of maternal serum levels of endothelial nitric oxide synthase, asymmetric dimethylarginine, and homocysteine in normal and preeclamptic pregnancies

Background

The aim of this study was to determine the maternal serum concentrations of eNOS, ADMA, and homocysteine in preeclamptic pregnancies.

Material/Methods

The study was carried out on 62 patients with pregnancy complicated by early onset and 53 patients with late onset preeclampsia. The control group consisted of 65 healthy normotensive pregnant patients. The serum eNOS, ADMA and homocysteine concentrations were determined using ELISA assays.

Results

Our study revealed elevated levels of homocysteine and ADMA in the serum of women with preeclampsia. The highest levels were observed in patients with early onset preeclampsia, but the differences between both groups of preeclamptic patients with early and late onset of preeclampsia were not statistically significant. Both groups of preeclamptic women had slightly lower levels of maternal serum endothelial nitric oxide synthase than in normotensive pregnant women, but these differences were not statistically significant.

Conclusions

The higher levels of homocysteine and ADMA observed in patients with early onset preeclampsia may suggest that higher levels of maternal serum homocysteine and ADMA correlate with the severity, and may determine the earlier clinical onset of the disease. The elevated levels of ADMA and the unchanged levels of eNOS in preeclamptic pregnancies suggest that NO deficiency in this pregnancy disorder results not from a reduced level or activity of eNOS, but from elevated levels of ADMA, an endogenous eNOS inhibitor. The lowering of increased levels of homocysteine and ADMA may be helpful in therapy of vascular disturbances occurring in preeclampsia.

Metabolic pathways involved in 2-methoxyestradiol synthesis and their role in preeclampsia

Preeclampsia (PE) remains a major cause of maternal/fetal morbidity-mortality worldwide. The first stage of PE is characterized by placental hypoxia due to a relative reduction in uteroplacental blood flow, resulting from restricted trophoblast invasion. However, hypoxia is also an essential element for the success of invasion. Under hypoxic conditions, 2-methoxyestradiol (2-ME) could induce the differentiation of cytotrophoblast cells into an invasive phenotype in culture. 2-Methoxyestradiol is generated by catechol-O-methyltransferase, an enzyme involved in the metabolic pathway of estrogens. During pregnancy, circulating 2-ME levels increase significantly when compared to the menstrual cycle. Interestingly, plasma levels of 2-ME are lower in women with PE than in controls, and these differences are apparent weeks or even months before the clinical manifestations of the disease. This article reviews the metabolic pathways involved in 2-ME synthesis and discusses the roles of these pathways in normal and abnormal pregnancies, with particular emphasis on PE.

Syncytin-1 modulates placental trophoblast cell proliferation by promoting G1/S transition

Placental syncytiotrophoblasts formed by the fusion of cytotrophoblasts constitute the interface between maternal and fetal circulations. The syncytium, composed of a continuous layer of syncytiotrophoblasts, assumes the fetal-maternal nutrient exchange, placental barrier, and endocrine functions important for the maintenance of normal pregnancy. Syncytin-1, an endogenous retroviral gene product, mediates the fusion of cytotrophoblasts. While the fusogenic function of syncytin-1 has been well established, little is known regarding its nonfusogenic activities. This study investigates the role of syncytin-1 in trophoblast proliferation. We found that syncytin-1 knockdown significantly inhibited BeWo cell growth and DNA synthesis. Moreover, time course studies on key cell cycle regulators demonstrated an upregulation of p15 and downregulation of CDK4, E2F1, PCNA, and c-Myc, which consequently led to a reduced level of CDK1. These results, together with those from flow cytometry analysis, indicated that syncytin-1 knockdown blocked the G1/S transition phase of the cell cycle. Moreover, syncytin-1 overexpression promoted CHO cell proliferation and led to changes opposite to those observed in syncytin-1 knockdown experiments, confirming the critical role of syncytin-1 for G1/S transition. Thus, syncytin-1, through both nonfusogenic and fusogenic, functions, may co-regulate the input (proliferation) and output (fusion) of the cytotrophoblast "pool". Such co-regulation could be an efficient way to achieve the balance between these two opposing processes, which is required for syncytium homeostasis. Since decreased syncytin-1 expression has been shown to be associated with preeclamptic and hypoxic condition, insufficient replenishing of the cytotrophoblast "pool" may contribute to syncytium deficiency, a critical pathological change frequently found in preeclamptic placentas.

Cystathionine β-synthase deficiency causes infertility by impairing decidualization and gene expression networks in uterus implantation sites

Hyperhomocysteinemia has been reported in human reproduction as a risk factor for early pregnancy loss, preeclampsia, and congenital birth defects like spina bifida. Female infertility was also observed in cystathionine beta synthase-deficient mice ( Cbs-KO) as an animal model for severe hyperhomocysteinemia. The aim for the present research was to elucidate the time-point of pregnancy loss and to pinpoint gene and cellular changes involved in the underlying pathological mechanism. By mating 90-day-old wild-type and Cbs-KO female mice with their homologous male partners, we found that pregnancy loss in Cbs-KO occurred between the 8th and 12th gestation day during placenta formation. DNA microarrays were carried out on uterus from implantation and interimplantation samples obtained on day 8. The results allowed us to select genes potentially involved in embryo death; these were individually confirmed by RT-qPCR, and their expressions were also followed throughout pregnancy. We found that changes in expression of Calb1, Ttr, Expi, Inmt, Spink3, Rpgrip1, Krt15, Mt-4, Gzmc, Gzmb, Tdo2, and Afp were important for pregnancy success, since a different regulation in Cbs-KO mice was found. Also, differences in relationships among selected genes were observed, indicating a dysregulation of these genes in Cbs-KO females. In conclusion, our data provide more information on the gene expression cascade and its timely regulated process required for a successful pregnancy. In addition, we unveil new potential avenues to explore further investigations in pregnancy loss.

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.

Birth outcomes of newborns after folic Acid supplementation in pregnant women with early and late pre-eclampsia: a population-based study

Objective. To evaluate the rate of preterm birth and low birth weight in the newborns of pregnant women with early and late onset pre-eclampsia according to folic acid supplementation. Study design. Birth outcomes of newborns were evaluated in 1,017 (2.7%) pregnant women with medically recorded pre-eclampsia and 37,134 pregnant women without pre-eclampsia as reference in the Hungarian Case-Control Surveillance System of Congenital Abnormalities, 1980-1996, in addition these study groups were differentiated according to the supplementation of high dose of folic acid alone from early pregnancy. Results. Pregnant women with pre-eclampsia associated with a higher rate of preterm birth (10.2% versus 9.1%) and low birthweight (7.9% versus 5.6%). There was a lower risk of preterm birth (6.8%) of newborn infants born to pregnant women with early onset pre-eclampsia after folic acid supplementation from early pregnancy though the rate of low birthweight was not reduced significantly. There was no significant reduction in the rate of preterm birth and low birthweight in pregnant women with late onset pre-eclampsia after folic acid supplementation. Conclusion. The rate of preterm birth in pregnant women with early onset pre-eclampsia was reduced moderately by high doses of folic acid supplementation from early pregnancy.

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.

Association of homocysteine, asymmetric dimethylarginine, and nitric oxide with preeclampsia

PURPOSE

Endothelial dysfunction underlies the pathogenesis of preeclampsia, but its mechanism has not yet been completely understood. In this study we have aimed to measure homocysteine (Hcy), asymmetric dimethylarginine (ADMA), and nitric oxide (NO) levels as endothelial dysfunction markers in preeclamptic women.

METHODS

Control-case study with 62 preeclamptic patients and 30 controls without pregnancy complications was conducted. Plasma total Hcy, determined by capillary column gas chromatography/mass spectrometry (GC/MS), was correlated with serum ADMA (determined by liquid chromatography/tandem mass spectrometry using (13)C(6)-L: -arginine as the internal standard) and NO (analyzed by GC/MS).

RESULTS

There was a highly significant increase in the plasma concentration of homocysteine (P < 0.001) and ADMA (P < 0.001) and a highly significant decrease in the plasma concentration of nitric oxide (P < 0.001) among the preeclamptic patients. The differences were more significant between mild and severe preeclampsia, with and without eclampsia, with and without HELLP (hemolysis, elevated serum level of liver enzymes, and low platelets). In the combined patients and control groups a highly significant positive correlation was found between the plasma concentrations of homocysteine and ADMA (r = 0.853, P < 0.001). In addition, significant negative correlations were detected between the plasma concentrations of nitric oxide and the plasma concentration of homocysteine (r = -0.870, P < 0.001) and ADMA (r = -0.895, P < 0.001). These significant correlations were found to persist, even when they were restricted to the preeclamptic patients.

CONCLUSIONS

The homocysteine-ADMA-NO may be at least partly responsible for etiology in preeclampsia and could be regarded as markers for the severity of the disease. Therefore, L: -arginine may represent a novel therapy for the treatment of preeclampsia.

Homocysteine effects on cellular glutathione peroxidase (GPx-1) activity under in vitro conditions

Hyperhomocysteinemia is associated with a lot of diseases including cardiovascular diseases and neural tube defect, but it has not been clarified exactly which mechanism is responsible for occurence disease. Here, homocysteine (Hcy) and cysteine (Cys), which are thiol containing amino acids, were examined for their effect on glutathione peroxidase (GPx) activity. It was observed that the GPx-1 activity was inhibited under severe hyperhomocysteinemia (50-500 microM Hcy) conditions, especially at low glutathione concentrations but that cysteine increased GPx-1 activity at low glutathione concentrations and inhibition clearly appeared at 500 microM Cys concentration.

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

Homocysteine is associated with endothelial dysfunction and cardiovascular disease, and elevated concentrations of homocysteine have been found in preeclampsia. The purpose of this study was to investigate maternal and fetal concentrations of total homocysteine and related metabolites (including cysteine, choline, and betaine), and possible associations with infant birth weight. Women with preeclampsia (n=47) and controls (n=51), who underwent cesarean section, were included. Maternal plasma, umbilical vein, and artery plasma were analyzed. Median concentrations of homocysteine, cysteine, choline, and betaine were significantly higher in women with preeclampsia than controls, both in maternal and fetal plasma. There were no differences in folate and vitamin B12 concentrations between the groups, neither for maternal nor fetal samples. Maternal homocysteine concentration was a negative predictor for birth weight only in the preeclampsia group. Elevated homocysteine and cysteine concentration in maternal circulation in preeclampsia is reflected in the fetal circulation. The clinical significance of elevated homocysteine and cysteine concentrations in maternal and fetal compartments in preeclampsia remain to be explored, both regarding fetal growth and development of disease later in life.

Combining mid-trimester maternal plasma homocysteine with uterine artery doppler velocimetry: is it useful?

OBJECTIVE

To investigate the possible association between mid-trimester maternal plasma homocysteine concentration, uterine artery Doppler measurements in a two-stage screening strategy, and outcome of pregnancy.

MATERIALS AND METHODS

This prospective observational study was conducted on healthy women undergoing screening for pre-eclampsia by uterine artery Doppler velocimetry at 20-22 and 24-26 weeks of gestation. Abnormal uterine artery blood flow was defined as an average resistance index (RI) > 0.58 and/or bilateral early diastolic notch. Homocysteine measurement was performed by two competitive immunoassay methods involving two steps at 20-22 and 24-26 weeks' gestation.

RESULTS

Sixty women enrolled. Abnormal Doppler findings were found in 18 of 60 (30%) women at 20-22 weeks of gestation. This proportion was reduced to 10% (6/60) at 24-26 weeks of gestation, and two of these six women developed pre-eclampsia later in pregnancy. There was no significant difference in the maternal plasma homocysteine levels in women with abnormal Doppler findings when compared with controls at first and second visits (p > 0.05).

CONCLUSION

Mid-trimester maternal homocysteine concentration is not elevated in women with abnormal uterine artery Doppler findings in a two-stage screening method.

Cystathionine β-synthase is essential for female reproductive function

In human reproduction, hyperhomocysteinemia has been reported as a risk factor for early pregnancy loss and congenital birth defects. Hyperhomocysteinemia is also recognized as a cause of maternal obstetric complications such as preeclampsia. The role of plasma hyperhomocysteinemia in female fertility was examined using cystathionine beta synthase knockout (cbs KO) mice. Cbs KO females were infertile, showed alterations in the estrus cycle and an increased progesterone response during pseudo-pregnancy induction. Both cbs KO ovaries and ovulated oocytes showed no major morphological alterations. However, placental and uterine masses were decreased at day 18 of pregnancy and showed morphological abnormalities. In cbs-KO pregnant females, the number of uterine implantation sites was not decreased despite the low number of surviving embryos. Fertility was restored when cbs-deficient ovaries were transplanted to normal ovarectomized recipients. We detected an increased uterine expression of Grp78, a marker of endoplasmic reticulum stress, which was accompanied by the decreased levels of uterine cbs mRNA in both hyperhomocysteinemic heterozygous (fertile) and homozygous (non-fertile) females. Our results indicate that cbs -/- female infertility is a consequence of the uterine failure and demonstrate that uterine endoplasmic reticulum stress and cbs expression are not determinant of infertility, suggesting that uterine dysfunction is a consequence of either hyperhomocysteinemia or other factor(s) in the uterine environment of cbs -/- animals. In summary, these studies demonstrate the potential importance of homocysteine levels for uterine handling of embryos.

Folate and human reproduction

The influence of folate nutritional status on various pregnancy outcomes has long been recognized. Studies conducted in the 1950s and 1960s led to the recognition of prenatal folic acid supplementation as a means to prevent pregnancy-induced megaloblastic anemia. In the 1990s, the utility of periconceptional folic acid supplementation and folic acid food fortification emerged when they were proven to prevent the occurrence of neural tube defects. These distinctively different uses of folic acid may well be ranked among the most significant public health measures for the prevention of pregnancy-related disorders. Folate is now viewed not only as a nutrient needed to prevent megaloblastic anemia in pregnancy but also as a vitamin essential for reproductive health. This review focuses on the relation between various outcomes of human reproduction (ie, pregnancy, lactation, and male reproduction) and folate nutrition and metabolism, homocysteine metabolism, and polymorphisms of genes that encode folate-related enzymes or proteins, and we identify issues for future research.

Combining 2nd-Trimester Maternal Serum Homocysteine Levels and Uterine Artery Doppler for Prediction of Preeclampsia and Isolated Intrauterine Growth Restriction

AIM

To evaluate the efficacy of a combined 2nd-trimester maternal serum homocysteine and uterine artery Doppler screening at 20 weeks of gestation for complications of pregnancy: preeclampsia, isolated intrauterine growth restriction (IUGR), placental abruption, and stillbirths.

METHODS

Consecutive singleton pregnancies without previous risk factors who had homocysteine measured as part of a serum-screening program for trisomy 21 had uterine artery Doppler performed. Sensitivity, specificity, positive and negative predictive values, odds ratio, and positive and negative likelihood ratios for the subsequent development of preeclampsia, isolated IUGR, placental abruption, stillbirth, and preterm delivery were calculated for the following methods (1) homocysteine cut-off level 6.3 micromol/l (95th centile); (2) on Doppler ultrasound bilateral notches with a mean resistance index (RI) >0.55 (50th centile), all unilateral notches with a mean RI >0.65 (80th centile), and absence of notches with a mean RI >0.7 (95th centile), and (3) Doppler ultrasound notch evaluation (bilateral, unilateral, absence as in method 2) combined with the homocysteine cut-off level of 6.3 micromol/l.

RESULTS

By using a logistic regression model, methods 1 and 2 predicted preeclampsia (p < 0.001), isolated IUGR (p < 0.01), and "any complication" (p < 0.01). The sensitivity for prediction of preeclampsia using the combined method (3) was 61.3% for a false-positive rate of 2%, better than that for isolated IUGR (54%) below the 5th centile and "any complication" (56%).

CONCLUSION

This prospective study confirms the potential of a combined method of elevated homocysteine and uterine artery Doppler screening for preeclampsia, isolated IUGR, and any obstetric complication.

Are plasma total homocysteine and other amino acids associated with glucose intolerance in uncomplicated pregnancies and preeclampsia?

OBJECTIVE

To evaluate the possible association between plasma total homocysteine or other amino acid concentrations and gestational diabetes or glucose intolerance (GI), in normotensive and preeclamptic pregnant women.

STUDY DESIGN

Prospective study including 243 pregnant women without previous risk factors. O'Sullivan test (plus oral glucose tolerance test when necessary) was performed, and homocysteine, B vitamins and plasma amino acids (AA) were measured at 24-25 weeks. Homocysteine and other amino acids were also measured in the third trimester.

RESULTS

Significant differences were observed in the incidence of preeclampsia in relation to abnormal glucose tolerance (P < 0.012). In normotensive patients, the glucose intolerance group showed significantly lower tHcy (P = 0.021) and increased plasma alanine concentrations in comparison with controls (P = 0.046), although no correlation was observed between both amino acid concentrations.

CONCLUSIONS

(a) A higher incidence of preeclampsia was observed in abnormal glucose tolerance patients, (b) total homocysteine and alanine were the only individual amino acids whose plasma concentrations varied according to the glucose tolerance classes, and (c) an association between hyperhomocysteinemia and glucose intolerance in our preeclamptic patients could not be demonstrated.

Mapping the Theories of Preeclampsia: The Role of Homocysteine

OBJECTIVE

We conducted a systematic review to examine the hypothesized mechanism through which homocysteine could lead to preeclampsia.

DATA SOURCES

We searched MEDLINE, EMBASE, BIOSIS, SciSearch, and bibliographies of primary and review articles, and we contacted experts.

METHODS OF STUDY SELECTION

Of the 25 relevant primary articles, 8 studies measured total serum homocysteine concentrations before the clinical onset of preeclampsia (1,876 women), whereas 17 measured it afterward (1,773 women). Meta-analytic techniques were used to examine consistency, strength, temporality, dose-response, and plausibility of the disease mechanisms implicating folate, vitamin B(6), vitamin B(12), genetic polymorphisms, oxidative stress, and endothelial dysfunction in the pathway linking hyperhomocysteinemia to preeclampsia.

TABULATION, INTEGRATION, AND RESULTS

Overall, there were higher serum homocysteine concentrations among pregnant women with preeclampsia than among those with uncomplicated pregnancies, but the results were heterogeneous (P = .12; I(2) = 38.8%). Among studies with temporality, the size of association was smaller than that among those without (weighted mean difference 0.68 mumol/L versus 3.36 mumol/L; P < .006). There was no dose-response relationship between homocysteine concentration and severity of preeclampsia. The mechanisms underlying hyperhomocysteinemia (folate and vitamin B(12) deficiency and genetic polymorphisms) were not found to be plausible, but markers of oxidative stress and endothelial dysfunction were higher in hyperhomocysteinemia.

CONCLUSION

Homocysteine concentrations are slightly increased in normotensive pregnancies that later develop preeclampsia and are considerably increased once preeclampsia is established. However, because of a lack of consistency in data, dose-response relationship, and biologic plausibility, the observed association cannot be considered causal from the current literature.

Association of pre-eclampsia with hyperhomocysteinaemia and methylenetetrahydrofolate reductase gene C677T polymorphism in a Turkish population

BACKGROUND

Hyperhomocysteinaemia is a common finding in a wide variety of pathological conditions that exhibit endothelial disturbances. In the pathogenesis of pre-eclampsia, endothelial cell activation or dysfunction has been proposed as a central feature, and the presence of hyperhomocysteinaemia in varying degrees has been detected. One of the known causes of hyperhomocysteinaemia is polymorphism in the methylenetetrahydrofolate reductase gene that lowers the activity of the enzyme.

AIMS

In the current study, we measured plasma homocysteine concentrations in pre-eclamptic pregnants, and searched for the altered methylenetetrahydrofolate reductase (MTHFR) gene in which the cytosine 677 was replaced by the thymine (C677T polymorphism).

METHODS

The study groups consisted of 64 pre-eclamptic and 47 normotensive healthy pregnant women in their third trimester. The C677T transition in the MTHFR gene was detected by HinfI restriction enzyme analysis and subsequent electrophoresis in a 3% agarose gel. Total homocysteine concentrations were measured by high performance liquid chromatography.

RESULTS

The prevalence of the homozygous mutant thymine-thymine genotype was non-significant in the pre-eclamptic group. Total homocysteine in the plasma of pre-eclamptic women was found to be increased in comparison with healthy pregnant women (P < 0.001). Any influence of the allelic distribution on plasma homocysteine concentrations was not detected in either group. However, pre-eclamptic patients bearing the non-mutated cytosine-cytosine genotype had significantly higher homocysteine levels than those with an uncomplicated pregnancy (P = 0.009), ruling out the possibility that the presence of a mutated allele is associated with the hyperhomocysteinaemia seen in pre-eclamptic women.

CONCLUSION

In our pre-eclamptic study population, a mild hyperhomocysteinaemia was observed. This finding seems to be a consequence of hypertension and vascular injury rather than an independent factor with a genetic origin.

Methylenetetrahydrofolate reductase gene polymorphisms in black South Africans and the association with preeclampsia

BACKGROUND

A methylenetetrahydrofolate reductase (MTHFR) polymorphism (1317T --> C) that occurs commonly in black African individuals prompted this study to establish whether this polymorphism, alone or in association with other MTHFR variants, is associated with preeclampsia in black South African women.

METHODS

A group of 204 black women with preeclampsia was examined for the 677C --> T, 1298A --> C and 1317T --> C MTHFR polymorphic alleles using standard techniques. Also examined were women with early-onset preeclampsia (n = 67) and gestational hypertension (n = 78). Results were compared with 338 ethnically matched normotensive pregnant women who had normal full-term gestations.

RESULTS

No differences in the 677T --> C or 1298A --> C MTHFR alleles were found between the study groups and controls; very few women were homozygous for either variant allele. Significant differences were observed for the 1317T --> C polymorphism: only 39% of preeclamptics were homozygous for the T allele compared with 52% of the control group [p = 0.002; 0.59 (0.42-0.83)]. Heterozygotes occurred significantly more frequently in preeclamptics (51%), compared with controls (41%) [p = 0.019; 1.49 (1.07-2.08)]. Allele frequencies also differed significantly between preeclamptics and controls [p = 0.003; 0.69 (0.53-0.88)]. Allele frequencies in women with gestational hypertension were statistically indistinguishable from those in controls.

CONCLUSION

The low frequencies of the 677C --> T and 1298A --> C MTHFR variant alleles in black South Africans imply little or no role for these mutations in preeclampsia in this population group. However, significant differences in the 1317T --> C allele in preeclamptics suggest that the MTHFR gene, or a closely associated gene, may still have some role, as yet undefined, in the pathogenesis of preeclampsia.

Homocysteine-induced enhancement of spontaneous contractions of myometrium isolated from pregnant women

BACKGROUND

Although many associations have been demonstrated between hyperhomocysteinemia and pregnancy complications, such as spontaneous abortion, preterm labor, preeclampsia and low birthweight, it is still not clear whether hyperhomocysteinemia is the cause or the consequence of these pregnancy complications. The aim of this study was to investigate the effects of homocysteine on the spontaneous contractility of isolated pregnant human myometrium.

METHODS

Myometrium samples obtained from women undergoing elective caesarean section were suspended in a jacketed organ bath containing Krebs' solution at 37 degrees C (pH 7.4), continuously gassed with 95% O2 and 5% CO2. After manifestation of spontaneous contractions under 2 g of resting tension, homocysteine was applied to the organ bath, and amplitude and frequency of contractions were evaluated at 20-min intervals. Statistical analysis of amplitude and frequency of the contractions was performed using the Kruskal-Wallis analysis of variance test.

RESULTS

Application of 0.1 mm homocysteine had no significant effect on either frequency (4.63 +/- 0.42 vs. 4.01 +/- 0.53 for the control period; p > 0.05) or amplitude (3.20 +/- 0.07 g vs. 3.15 +/- 0.07 g; p > 0.05) of spontaneous contractions, while 1 and 2 mm homocysteine significantly increased the frequency (8.54 +/- 0.62 vs. 3.9 +/- 0.44, p < 0.02, and 12.32 +/- 0.72 vs. 3.96 +/- 0.51, p < 0.001, respectively) of spontaneous contractions but caused only a modest change in amplitude (2.92 +/- 0.04 g vs. 2.87 +/- 0.05 g, p > 0.05, and 3.02 +/- 0.06 g vs. 2.93 +/- 0.05 g, p > 0.05, respectively).

CONCLUSION

Results from this study indicate for the first time that homocysteine causes enhancement of spontaneous contractions of myometrium derived from pregnant women.

Homocysteine and other plasma amino acids in preeclampsia and in pregnancies without complications

OBJECTIVES

To evaluate a). the plasma amino acid changes observed in pregnant women (n = 124) and b). the homocysteine and other amino acid changes in preeclampsic patients (n = 18), and to determine c) whether these changes were also evident in nonpregnant women with a prior history of preeclampsia (n = 18).

DESIGN AND METHODS

Case-control study. Plasma total homocysteine (tHcy): HPLC with fluorescence detection, and amino acids (AA): ion exchange chromatography.

RESULTS

a). Significantly lower absolute AA values were observed in the pregnant controls for homocysteine, total, essential, and nonessential AA compared with nonpregnant controls. b. In preeclampsia, significantly higher absolute values of tHcy, total, essential and nonessential AA were observed, but relative values referred to total AA were not different. These changes corrected after delivery.

CONCLUSIONS

Hyperhomocysteinemia and an increase in most AA levels were observed in preeclampsia. Relative AA values suggested that these changes might be explained by fluctuations in plasma volume. Abnormal AA levels corrected after delivery.

Plasma total homocysteine in uncomplicated pregnancy and in preeclampsia

OBJECTIVES

(a) To establish the reference values for plasma total homocysteine in our pregnant population. (b) To determine the possible association between hyperhomocysteinemia and preeclampsia in our geographical area.

STUDY DESIGN

Control-case study with 32 preeclamptic patients and 64 controls without pregnancy complications. Plasma total homocysteine, determined by HPLC (fluorescence detection), was correlated with serum folate and Vitamin B(12) (analyzed by competitive protein binding chemiluminescent assay).

STATISTICAL ANALYSES

Mann-Whitney, Wilcoxon and Spearman test (SPSS, 10.0).

RESULTS

Homocysteine concentrations in the controls were significantly higher while folate was significantly lower in the third trimester of pregnancy when compared with the second (P<0.0001). Homocysteine and folate values were significantly higher in patients compared with controls in the third trimester (P=0.005 and 0.005, respectively). The OR for preeclampsia in hyperhomocysteinemia was 7.7 (95% CI: 1.7-34.8).

CONCLUSION

Pregnant women with hyperhomocysteinemia have a 7.7-fold risk for preeclampsia (CI 95%: 1.7-34.8) compared with normal controls.

Homocysteine oxidation and apoptosis: a potential cause of cleft palate

Cleft palate is the most common craniofacial anomaly. Affected individuals require extensive medical and psychosocial support. Although cleft palate has a complex and poorly understood etiology, low maternal folate is known to be a risk factor for craniofacial anomalies. Folate deficiency results in elevated homocysteine levels, which may disturb palatogenesis by several mechanisms, including oxidative stress and perturbation of matrix metabolism. We examined the effect of homocysteine-induced oxidative stress on human embryonic palatal mesenchyme (HEPM) cells and demonstrated that biologically relevant levels of homocysteine (20-100 microM) with copper (10 microM) resulted in dose-dependent apoptosis, which was prevented by addition of catalase but not superoxide dismutase. Incubation of murine palates in organ culture with homocysteine (100 micro) and CuSO(4) (10 microM) resulted in a decrease in palate fusion, which was not significant. Gelatin gel zymograms of HEPM cell-conditioned media and extracts of cultured murine palates, however, showed no change in the expression or activation of pro-matrix metalloproteinase-2 with homocysteine (20 microM-1 mM) with or without CuSO(4) (10 microM). We have demonstrated that biologically relevant levels of homocysteine in combination with copper can result in apoptosis as a result of oxidative stress; therefore, homocysteine has the potential to disrupt normal palate development.

Hiperhomocisteinemia durante el embarazo como factor de riesgo de preeclampsia

A revision about the role of hyperhomocysteinemia in the development of preeclampsia is presented, which summarises our experience in different biochemical and genetic points in relation to this possible association. Plasma total homocysteine concentrations (tHcy) during pregnancy were significantly lower than those of non-pregnant women: 2nd trimester (median, 5.3 micromol/l; range, 3.1-10.0 micromol/l); 3rd trimester (median, 6.3 micromol/l; range, 3.2-13.0 micromol/l). Hyperhomocysteinemia (tHcy>P95) was established as values higher than 7.7 micromol/l in the 2nd trimester, and as values higher than 10.5 micromol/l in the 3rd trimester of pregnancy. We found an association between hyperhomocysteinemia and preeclampsia: tHcy values were significantly higher in the preeclamptic group than in uncomplicated pregnancies; the OR for preeclampsia in hyperhomocysteinemic patients was 7.7 (CI 95%, 1.7-34.8). The other amino acid concentrations were also higher in preeclamptic women. The negative correlation observed between homocysteine and folate in the control group, was not present in preeclamptic women. An association between homocysteine concentrations in preeclampsia and glucose intolerance was not observed. The Doppler study of uterine artery flow velocity waveforms seems to be a good screening method to identify pregnancies at high risk of preeclampsia. The addition of homocysteine determination did not usefully improve its predictive value. The polymorphisms in the main genes involved in folate-homocysteine metabolism studied could not be considered as the determinants of the hyperhomocysteinemia observed in preeclamptic pregnants.