Plasma homocysteine levels elevated and inversely related to insulin sensitivity in preeclampsia

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 level and gestational diabetes mellitus: a systematic review and meta-analysis

AIMS

It is reported that elevated homocysteine (Hcy) level represents an independent risk factor for gestational diabetes mellitus (GDM). However, the relationship between Hcy level and GDM remains controversial. Our study aimed to systematically review available literature linking Hcy to GDM for a comprehensive understanding of the relationship between circulating Hcy level and GDM in humans.

METHODS

PubMed, The Cochrane Library, and Web of Science were searched for studies published up to January 2021. Manual searches of references of the relevant studies were also conducted. Standard mean difference (SMD) with 95% confidence interval (95%CI) were calculated to evaluate the relationship between Hcy level and GDM using the Review Manager 5.3 and Stata 12.0.

RESULTS

Of 106 references reviewed, 12 studies with a total of 712 GDM patients contributed to the present meta-analysis. Hcy level was significantly elevated in women with GDM compared with those without GDM (SMD = 0.55; 95% CI: 0.25-0.85, p = .0003). In the subgroup meta-analyses, this evidence was more consistent among women with Hcy sampling during the second trimester (SMD = 0.76, 95% CI: 0.34-1.18, p = .0004) and with average age ≥30 years (SMD = 0.69, 95% CI: 0.25-1.12, p = .002).

CONCLUSION

The evidence indicated that the level of circulating Hcy was significantly elevated among women with GDM compared with those with normal glucose tolerance, especially with mean age ≥30 years and in the second trimester.

Hyperhomocysteinemia as a Risk Factor and Potential Nutraceutical Target for Certain Pathologies

Hyperhomocysteinemia is recognized as a risk factor for several diseases, including cardiovascular and neurological conditions. Homocysteine (HCys) is a key metabolite involved in the biosynthesis and metabolism of methionine (Met), which plays a pivotal role in the physiological cell's life cycle. The biochemistry of Met is finely regulated by several enzymes that control HCys concentration. Indeed, balanced activity among the enzymes is essential for the cell's well-being, while its malfunction could raise HCys concentration which can lead to the onset of several pathological conditions. The HCys concentration increase seems to be caused mainly by the widely diffused polymorphisms of several enzymes. Nowadays, a blood test can easily detect elevated concentrations of HCys, referred to as Hyperhomocysteinemia (HHCys). Prolonged exposure to this condition can lead to the onset of cardiovascular disease and can lead to the development of atherosclerosis, stroke, inflammatory syndromes like osteoporosis and rheumatism, as well as neuronal pathologies including Alzheimer's and Parkinson's diseases. In this review, we analyzed the literature of several pathological conditions in which the molecular pathways of HHCys are involved. Interestingly, several observations indicate that the calibrated assumption of correct doses of vitamins such as folic acid, vitamin B6, vitamin B12, and betaine may control HHCys-related conditions.

Effects of folic acid supplementation on serum homocysteine and lipoprotein (a) levels during pregnancy

Introduction:There are many ideas concerning the etiology and pathogenesis of preeclampsia including endothelial dysfunction, inflammation and angiogenesis. Elevated levels of total homocysteine (Hcy) and lipoprotein (a) [Lp(a)] are risk factors for endothelial dysfunction. This study aimed to evaluate the effect of high dose folic acid (FA) on serum Hcy and Lp(a) concentrations with respect to methylenetetrahydrofolate reductase (MTHFR) polymorphisms 677C→T during pregnancy.

Methods: In a prospective uncontrolled intervention, 90 pregnant women received 5 mg FA supplementation before pregnancy till 36th week of pregnancy. The MTHFR polymorphisms 677C→T, serum lactate dehydrogenase activity, urine protein and creatinine concentrations were measured before starting folic acid administration. Serum levels of Hcy and Lp(a) were determined before and after completion of folic acid supplementation period.

Results: Supplementation of the patients with FA for 36 week decreased the median (minimum– maximum) levels of serum Hcy from 11.40 μmol/L (4.40-28.70) to 9.70 (1.60-20.80) μmol/L (p=0.001). There was no significant change in serum Lp(a) after FA supplementation (p=0.17). The overall prevalence of genotypes in pregnant women that were under study for MTHFR C677T polymorphism was 53.3% CC, 26.7% CT and 20.0% TT. There was no correlation between decreasing level of serum Hcy in the patients receiving FA and MTHFR polymorphisms.

Conclusion:Although FA supplementation decreased serum levels of Hcy in different MTHFR genotypes, serum Lp(a) was not changed by FA supplements. Our data suggests that FA supplementation effects on serum Hcy is MTHFR genotype independent in pregnant women.

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.

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.

Effect of weight reduction on concentration of plasma total homocysteine in obese Japanese men

SUMMARY

OBJECTIVE

To test whether weight reduction would lower tHcys concentration, and whether adding exercise training to dietary weight reduction would further reduce tHcys concentration over diet alone.

DESIGN

A randomized, controlled, prospective, 14-week weight-loss intervention.

SETTING AND PARTICIPANTS

Forty-eight obese Japanese men aged 27-66 years were assigned to 2 subgroups depending on the type of treatment: diet alone (DA) and diet plus exercise training (DE). Concentration of tHcy was measured in frozen plasma samples by an HPLC method.

RESULTS

Body weight decreased significantly for both groups: DA -7.8 ± 3.2 kg and DE -9.1 ± 3.6 kg. A significant decrease was found in tHcys concentration of the DE group (-2.3 ± 5.0 μmol/L) but not of the DA (-0.3 ± 2.7 μmol/L). For subjects with hyperhomocysteinemia (≥15 μmol/L, n = 17), tHcys concentration decreased from 20.1 ± 7.0 to 13.9 ± 3.0 μmol/L (p < 0.01) for the DE group (n = 8) but did not change for the DA group (16.6 ± 1.9 μmol/L → 15.4 ± 2.3 μmol/L, n = 9). Furthermore, to consider a statistical phenomenon "regression to the mean", we excluded two subjects with the highest two tHcys values of the DE group. The DE group (n = 7) still displayed a significant reduction after the exclusion.

CONCLUSIONS

A weight reduction with diet alone did not improve tHcy levels. Adding aerobic exercise training to a dietary weight-reduction program may be effective for a reduction in tHcy.

Methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and risk of preeclampsia: an updated meta-analysis based on 51 studies

BACKGROUND AND AIMS

The methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism has been considered to be associated with preeclampsia (PE), but the results from previous studies were conflicting. The present study aimed at investigating the frequency of preeclampsia according to the distribution polymorphism using a meta-analysis on the published studies.

METHODS

The English and Chinese databases were searched to identify eligible studies published in English before August 2012. Data were extracted using standardized methods. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI). Begg's test was used to measure publication bias.

RESULTS

A total of 51 case-control studies containing 6,403 patients and 11,346 controls were involved in this meta-analysis. Significant associations were detected between MTHFR C677T polymorphism and risk of PE in the overall population for TT vs. CC (OR = 1.280, 95% CI: 1.074-1.525), recessive model (OR = 1.264, 95% CI: 1.067-1.303), and dominant genetic model (OR = 1.174, 95% CI: 1.057-1.303); in Caucasian population for dominant model (OR = 1.136, 95% CI: 1.022-1.263), and in East Asia population for TT vs. CC (OR = 2.199, 95% CI: 1.366-3.924) CT vs. CC (OR = 1.453, 95% CI: 1.001-2.109), recessive model (OR = 1.742, 95% CI: 1.202-2.525), and dominant model (OR = 1.783, 95% CI: 1.271-2.501). Conversely, no associations were detected in Latin America, South Asia, and Africa populations.

CONCLUSIONS

Results of the meta-analysis suggest that the MTHFR C677T polymorphism was associated with risk of PE in overall, Caucasian, and East Asia populations. Nevertheless, the results for Latino, East Asians, South Asians and Africans should be interpreted with caution due to the small sample size.

Homocysteine and ghrelin link with polcystic ovary syndrome in relation to obesity

AIM

Elevated levels of plasma homocysteine and depressed ghrelin levels have been found to be associated with insulin resistance in a number of clinical situations, such as polycystic ovary syndrome. This study was designed to determine the relationship of plasma homocysteine and ghrelin levels with obesity in polycystic ovary syndrome.

MATERIAL AND METHODS

Forty-four adolescents and young women (24 lean, 20 obese) 16-21 years old with polycystic ovary syndrome and age matched 20 healthy adolescents and young women were participated the study. Fasting samples were collected for serum vitamin B12, folate, plasma total homocysteine and ghrelin levels. Serum levels of follicle-stimulating hormone, luteinizing hormone, dehydroepiandrosterone sulfate, insulin, 17-hydroxyprogesterone, free testosterone, sex-hormone binding globulin were measured. Also, serum concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides were determined. Oral glucose tolerance test was done, and HOMA-IR index was used to define insulin resistance.

RESULTS

Plasma total homocysteine levels were significantly higher in women with polycystic ovary syndrome and their plasma ghrelin levels were depressed compared to control group (P < 0.05). Obese adolescents with polycystic ovary syndrome had more depressed plasma ghrelin levels compared to lean ones (P < 0.05). Homocysteine levels didn't correlate with body mass index, but positively correlated with insulin resistance (P < 0.05).

CONCLUSION

Elevated plasma homocysteine levels in polycystic ovary syndrome was independent from obesity. Adversely ghrelin levels were depressed with polycystic ovary syndrome in relation to obesity.

Plasma homocysteine concentrations and insulin resistance in preeclampsia

The correlation between insulin resistance and homocysteine levels in patients with preeclampsia indicate that insulin resistance in preeclampsia is related to endothelial dysfunction.

Hyperhomocysteinemia induces insulin resistance in male Sprague-Dawley rats

Association between elevated plasma homocysteine levels and insulin resistance has been reported, however, whether hyperhomocysteinemia induces insulin resistance or it is actually hyperinsulinemia that causes elevated plasma homocysteine levels, the direction of causality in this association is not still clear. In this study, we examined the hypothesis that hyperhomocysteinemia may cause hyperinsulinemia leading to insulin resistance in rats. Plasma glucose, insulin and total homocysteine concentrations were determined in two groups of male Sprague-Dawley rats, a test group that administered with homocysteine and a control group with no homocysteine in daily drinking water before and after 50 days. Oral glucose tolerance tests were also performed in control and test groups before and after 50 days. Mean fasting plasma insulin level was significantly higher (42.5+/-20.4 mU/L versus 23.2+/-5.9 mU/L, p=0.01), whereas mean glucose: insulin ratio was significantly lower in test rats than in control rats (0.12+/-0.07 versus 0.17+/-0.05, p=0.04) after 50 days. In addition, mean homeostasis assessment insulin resistance index was significantly higher in test rats than in control rats (7.5+/-3.5 versus 4.0+/-1.6, p=0.02) after 50 days. The mean plasma glucose level was not significantly different (4.1+/-1.1 mmol/L versus 3.9+/-0.8 mmol/L, p=0.57) between controls and test rats, however, the results from oral glucose tolerance tests showed the development of insulin resistance in test rats after 50 days administration of homocysteine. Results from this in vivo study suggest that homocysteine can cause insulin resistance and this relationship may need to be considered when evaluating the role of plasma homocysteine as a risk factor in patients with obesity and type II diabetes.

Elevated plasma homocysteine concentrations in severe preeclampsia and eclampsia

Homocysteine is an essential amino acid required for the growth of cells and tissues in the human body. Maternal hyperhomocysteinemia is associated with a number of placenta-mediated diseases such as preeclampsia. The aim of this study was to evaluate the plasma level of homocysteine and its association with severity of preeclampsia. A case-control study was performed with 32 mild preeclamptic patients, 25 severe preeclamptic patients, 16 eclamptic patients and 34 controls. Maternal plasma homocysteine concentration was measured prospectively at antenatal period by high-performance liquid chromatography. There were no significant differences in demographic characteristics between the study and control groups. Mean plasma levels of homocysteine in women with severe preeclampsia (16.7 +/- 10.1 micromol/l, mean +/- S.D., n = 25) and eclampsia (16.5 +/- 9.6 micromol/l, mean +/- S.D., n = 16) were significantly higher than those in mild preeclampsia (7.7 +/- 2.4 micromol/l, mean +/- S.D., n = 32) and controls (6.7 +/- 1.6 micromol/l, mean +/- S.D., n = 34) (p < 0.0001). It should be noted that plasma levels of homocysteine are not significantly different between mild preeclampsia and controls. In conclusion, plasma homocysteine concentrations are increased in severe preeclampsia and eclampsia, but not in mild preeclampsia.

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.

Relationship between homocysteine and insulin resistance in women with polycystic ovary syndrome

Hyperhomocysteinemia is a risk factor for atherosclerotic vascular diseases. It is known that plasma homocysteine levels are higher in polycystic ovary syndrome (PCOS) patients than in healthy subjects. The aim of our study was to determine the relationship between plasma homocysteine level and insulin resistance in women with PCOS. Twenty-nine patients (age, 23.90 +/- 5.86 years) and twenty-five healthy subjects (age, 25.24 +/- 4.28 years) were involved in the study. Plasma levels of fasting insulin, glucose, homocysteine, FSH, and LH levels were measured. A statistically significant difference in plasma concentrations of HOMA index, homocysteine, basal insulin levels and LH/FSH ratios was observed between groups (P = 0.001, P = 0.001, P = 0.001, and P = 0.01, respectively). There was no relationship between Hcy and the other variables. In multiple logistic regression analysis, age, BMI and insulin resistance were not predictors of Hcy.

Thrombophilia and pregnancy complications

OBJECTIVE

This systematic review examines the strength of the association between thrombophilia and recurrent pregnancy loss and other serious obstetric complications. Study design Electronic databases and manual bibliography searches were used to identify studies evaluating the association between thrombophilia and pregnancy loss, preeclampsia, fetal growth retardation, and placental abruption.

RESULTS

Thrombophilic disorders are associated with an increased risk of fetal loss in the majority of case control and cohort studies. The risk is increased throughout pregnancy, but may be higher in the second and third trimester. The common pathologic finding of placental infarction suggests unexplained fetal loss may result from uteroplacental insufficiency and thrombosis. Thrombophilic disorders are not consistently associated with preeclampsia, fetal growth retardation, or placental abruption. Preliminary data suggest prophylactic anticoagulation may improve outcome in thrombophilic women with unexplained recurrent fetal loss.

CONCLUSION

Women with thrombophilia have an increased risk of pregnancy loss and possibly other serious obstetric complications, although definition of the magnitude of risk will require prospective longitudinal studies. Preliminary data suggesting prophylactic anticoagulation may improve gestational outcome provide a rationale for prospective randomized trials in thrombophilic women with unexplained recurrent fetal loss.

Homocysteine plasma concentration levels for the prediction of preeclampsia in women with chronic hypertension

OBJECTIVE

The purpose of this study was to evaluate prospectively midtrimester homocysteine concentration levels for the prediction of superimposed preeclampsia in women with chronic hypertension.

STUDY DESIGN

Between March 1, 2000, and February 1, 2002, pregnancies that were complicated by chronic hypertension that required medication had homocysteine, vitamin B(12), and folate concentrations measured between 16 and 20 weeks of gestation. All women received folate supplementation. An upper limit threshold for increased homocysteine was defined as the mean value plus 2 SDs.

RESULTS

Fifty-seven women were enrolled. Mean homocysteine concentration levels were 5.1+/-1.7 micromo/L for the 16 women who had preeclampsia compared with 4.7+/-1.3 micromo/L for the 41 women without preeclampsia (P=.56). Two of 16 women with preeclampsia (13%) had concentration levels that exceeded the 95th percentile (6.9 micromo/L) compared with 2 of 41 women (5%) without preeclampsia (P=.31). The sensitivity and specificity were 13% (95% CI, 1.6-38.3) and 95.1% (95% CI, 83.5-99.4), respectively.

CONCLUSION

Second-trimester homocysteine concentration levels were not helpful in the prediction of preeclampsia in chronically hypertensive women.

Distribution of serum total homocysteine and its association with diabetes and cardiovascular risk factors of the insulin resistance syndrome in Mexican American men: the Third National Health and Nutrition Examination Survey

BACKGROUND

Few data have been published on the association of variables of the insulin resistance syndrome and serum total homocysteine (tHcy), a putative risk factor for cardiovascular morbidity, in representative samples of total populations or in Hispanic Americans.

METHODS

To describe the distributions of serum tHcy concentration and variables associated with insulin resistance in Mexican American men and to assess their association, data from a cross-sectional survey of a large national sample, the Third National Health and Nutrition Examination Survey were analyzed. Analyses were restricted to Mexican American men aged 40-74 years with data on glycated hemoglobin (%), body mass index (BMI), body fat distribution, HDL cholesterol, fasting serum insulin, serum triglycerides and serum tHcy concentrations.

RESULTS

Cumulative distributions of serum tHcy shifted to the right with increasing age. Log serum tHcy was not associated with prevalence of diagnosed diabetes mellitus or glycated hemoglobin percent or other risk factors other than age. Log serum tHcy concentration showed borderline significant (p = 0.049) positive association with fasting serum insulin concentration independent of age and BMI, only in men aged 60-74.

CONCLUSION

No consistent association of tHcy with diabetes prevalence or variables of the insulin resistance syndrome were found in Mexican American men aged 40-74 years. Further research is needed on the associations of serum tHcy concentration with insulin resistance and other components of the insulin resistance syndrome in persons of varying ethnicity.

Homocysteine, folic acid and B-group vitamins in obstetrics and gynaecology

The amino acid homocysteine is of considerable medical importance because it is involved in the etiopathogeny of cardiovascular diseases. Hyperhomocysteinemia is a factor in the vascular damage that predisposes thrombogenesis and arteriosclerosis. It has also been related to a range of obstetric and gynecologic complications. Numerous studies have demonstrated the association between increased levels of homocysteine and neural tube defects (NTD) and other congenital defects, spontaneous miscarriages, intrauterine growth retardation (IGR), preeclampsia and intrauterine fetal death. Folic acid and other B-group vitamins (B6 and B12) take part in the metabolism of homocysteine and the preventive administration of these vitamins may reduce some of the complications.

Plasma thiols and androgen levels in polycystic ovary syndrome

Homocysteine is a risk factor for ischemic heart disease; similarly as is hyperlipidemia or insulin resistance, which frequently occur in women with polycystic ovary syndrome. We examined the relationships between thiols and hormonal status or insulin resistance in 40 women (aged 25.8 +/- 7 years) with polycystic ovary syndrome and in 11 controls (33 +/- 5 years). Blood levels of homocysteine, glutathione, total and high density lipoprotein (HDL)-cholesterol, triglycerides, insulin, sex hormone-binding globulin, testosterone, androstenedione, dehydroepiandrosterone sulfate, and estradiol were determined. Student's t test and Spearman correlations were computed after adjustment for body mass index (BMI) and age. Homocysteine was significantly higher in polycystic ovary syndrome patients than in the control group (10.3 +/- 2.87 vs. 8.78 +/- 2.75 micromol/l; p < 0.05). In women with polycystic ovary syndrome, there were significant positive correlations between homocysteine and androstenedione (r = 0.329; p < 0.05) and glutathione and dehydroepiandrosterone sulfate (DHEA-S) (r = 0.469; p < 0.05). We conclude that homocysteine is increased in women with polycystic ovary syndrome and is probably linked to androgen levels but not to markers of insulin resistance or with lipid metabolism.

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.

Methylenetetrahydrofolate reductase polymorphism, type II diabetes mellitus, coronary artery disease, and essential hypertension in the Czech population

Increased plasma concentrations of homocysteine have been found in patients with coronary artery disease (CAD) and essential hypertension (EH) and in patients with diabetic complications. The 677C/T methylenetetrahydrofolate reductase (MTHFR) gene polymorphism is related to the MTHFR enzyme activity and to the plasma homocysteine concentration. This study was designed to investigate an association of this polymorphism with CAD, EH, and type II diabetes mellitus in the Czech population. The MTHFR genotypes were assessed by the polymerase chain reaction-based methodology in a sample of 1199 unrelated Caucasian subjects with CAD, EH, type II diabetes, or a combination of these diseases, and in healthy subjects. Allele frequencies of the MTHFR polymorphism differed considerably between women with and without type II diabetes mellitus (P = 0.00069), with a higher frequency of the C allele in the diabetic women. In addition, the MTHFR T allele frequency was significantly higher in normotensive subjects with CAD compared with normotensive subjects without this disease (P = 0.020). Both associations were confirmed by multiple logistic regressions. In conclusion, while the C allele of the 677C/T MTHFR polymorphism is associated with type II diabetes mellitus in women, the T allele is associated with CAD only in normotensive subjects of Czech origin.

Failure of the combination of sequential oral and transdermal estradiol plus norethisterone acetate to affect plasma homocysteine levels

OBJECTIVE

A high level of plasma homocysteine may be deleterious to vascular health. We therefore compared the effect of combinations of sequential oral and transdermal estradiol plus norethisterone acetate on plasma homocysteine.

DESIGN

Prospective, randomized study.

SETTING

Outpatient department of obstetrics and gynecology in a university hospital.

PATIENT(S)

Forty-two healthy, nonsmoking postmenopausal women starting hormone replacement therapy (HRT) to control climacteric symptoms.

INTERVENTION(S)

In a randomized order, the women started using either oral HRT (2 mg of estradiol on days 1-12, 2 mg of estradiol plus 1 mg of norethisterone acetate (NETA) on days 13-22, and 1mg of estradiol on days 23-28; n = 21) or transdermal HRT (50 microg/d of estradiol on days 1-28 and 250 microg/d of norethisterone acetate on days 15-28, n = 21) for 1 year.

MAIN OUTCOME MEASURE(S)

Fasting plasma levels of homocysteine were measured before the treatment and during the combined estradiol-plus-NETA phases of the sixth and 12th treatment cycles.

RESULT(S)

Basal homocysteine levels in the oral group (8.2 +/- 3.1 micromol/L, mean plusmn;SD) and transdermal group (8.7 plusmn; 1.8 micromol/L, mean plusmn;SD) were not affected by the estradiol-plus-NETA combination.

CONCLUSION(S)

Neither an oral nor a transdermal combination of sequential estradiol and NETA causes significant changes in plasma homocysteine in Finnish postmenopausal women with normal baseline homocysteine levels.

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

We examined the hypothesis that hyperhomocyst(e)inaemia in the maternal or fetal circulation is associated with placental vascular disease with either the maternal syndrome of pre-eclampsia and/or fetal syndrome of growth restriction. Maternal plasma homocyst(e)ine levels were significantly higher in pregnancies complicated by pre-eclampsia, pregnancies with evidence of umbilical placental vascular disease, and pregnancies with both complications compared with the normal pregnancy group. In the fetal circulation mean plasma homocyst(e)ine concentration was significantly higher in the pre-eclampsia group compared with the normal group. The results suggest that hyperhomocyst(e)inaemia may be a risk marker for placental vascular disease and maternal pre-eclampsia. The elevated fetal plasma homocyst(e)ine concentrations, found only in the group of pregnancies with pre-eclampsia in the absence of umbilical placental vascular disease, may be due to an effect of placental vascular disease on homocyst(e)ine transfer from the maternal to fetal circulation.

Leptin during and after preeclamptic or normal pregnancy: its relation to serum insulin and insulin sensitivity

Hyperleptinemia may be part of the insulin resistance syndrome. We studied serum leptin in preeclampsia, which is an insulin-resistant state, and sought associations between leptin and insulin or insulin sensitivity during and after pregnancy. Twenty-two proteinuric preeclamptic women and 16 normotensive controls were studied during the third trimester. Leptin was higher in preeclampsia (mean +/- SE, 34.6 +/- 3.9 v 20.0 +/- 3.3 microg/L, P = .002) and correlated directly with the level of proteinuria (r = .47, P = .03) and normal pregnancy (r = .52, P = .04), whereas insulin sensitivity as assessed by an intravenous glucose tolerance test showed no relationship to leptin. Leptin was 19.0 +/- 3.6 microg/L in 14 preeclamptic women and 10.1 +/- 2.0 microg/L (P = .11) in 11 controls 3 months after delivery. Leptin correlated directly with insulin both in preeclamptic puerperal women (r = .63, P = .02) and in controls (r = .81, P = .003). Leptin and insulin sensitivity correlated only in preeclamptic puerperal women (r = -.59, P = .02). In conclusion, (1) serum leptin is elevated in preeclampsia, (2) insulin is an important determinant of serum leptin in preeclamptic and normotensive women both during pregnancy and in the puerperium, and (3) hyperleptinemia may be part of the insulin resistance syndrome also in women with prior preeclampsia.

Hypertension in pregnancy: new recommendations for management

Hypertension in pregnancy is a frequent complication that has substantial adverse perinatal outcomes. Hypertension may be preexisting (chronic) essential or secondary hypertension; a second entity is pregnancy induced (gestational hypertension, preeclampsia). Recent advances have identified newer markers for pregnancy hypertension: several potential candidate genes may explain the apparent family inheritance of preeclampsia, and some thrombophilic markers have been associated with the condition. Management options for mild to moderate hypertension include a short hospital stay to exclude ongoing severe hypertension and to ascertain fetal well-being. Outpatient care with appropriate maternal and fetal surveillance, including umbilical artery doppler velocimetry, is recommended for better perinatal outcomes. Acute care for severe hypertension includes the use of magnesium sulfate to prevent eclampsia and antihypertensive medication. Expeditious delivery is recommended when the maternal or fetal states cannot be stabilized. Follow-up after delivery allows the uncovering of any other coexisting hypertensive or cardiovascular disorder.

Interaction of the protein C/protein S anticoagulant system, the endothelium and pregnancy

Normal pregnancy is associated with significant changes in haemostasis, lipid metabolism and endothelial function. This suggests that maternal adaptation in these systems is required for successful pregnancy outcome. A number of acquired and heritable prothrombotic abnormalities are associated with complications in pregnancy. A common feature of these abnormalities is their ability to alter endothelial function or the protein C/protein S system and increase thrombin generation. In this review the normal function of the endothelium and the protein C/protein S system is detailed. The changes which characterize normal and complicated pregnancies are outlined and the evidence for the impact of heritable and acquired disorders of the protein C/protein S system on pre-eclampsia and fetal loss are discussed.