Mass spectrometry evidence for formation of estrogen-homocysteine conjugates: estrogens can regulate homocysteine levels

The Role of Estrogen across Multiple Disease Mechanisms

Estrogen is a significant hormone that is involved in a multitude of physiological and pathological processes. In addition to its pivotal role in the reproductive system, estrogen is also implicated in the pathogenesis of a multitude of diseases. Nevertheless, previous research on the role of estrogen in a multitude of diseases, including Alzheimer's disease, depression, cardiovascular disease, diabetes, osteoporosis, gastrointestinal diseases, and estrogen-dependent cancers, has concentrated on a single disease area, resulting in a lack of comprehensive understanding of cross-disease mechanisms. This has brought some challenges to the current treatment methods for these diseases, because estrogen as a potential therapeutic tool has not yet fully developed its potential. Therefore, this review aims to comprehensively explore the mechanism of estrogen in these seven types of diseases. The objective of this study is to describe the relationship between each disease and estrogen, including the ways in which estrogen participates in regulating disease mechanisms, and to outline the efficacy of estrogen in treating these diseases in clinical practice. By studying the role of estrogen in a variety of disease mechanisms, it is hoped that a more accurate theoretical basis and clinical guidance for future treatment strategies will be provided, thus promoting the effective management and treatment of these diseases.

Association of plasma homocysteine with peripheral arterial disease in the hypertensive adults: A cross-sectional study

Increased plasma homocysteine (Hcy) has been identified as one of the important risk factors for cardiovascular disease. However, the association between plasma Hcy and peripheral artery disease (PAD) is still controversial. This study aimed to investigate the association between plasma Hcy and PAD and the potential modifier factors in Chinese hypertensive adults. A total of 25 300 hypertensive patients aged 18 years or older were included in the analysis in this cross-sectional study. The outcome was PAD, which defined as an ankle-brachial index ≤0.90 in either limb. Multiple logistic regression was used to analyze the relationship between plasma Hcy and PAD. The median plasma Hcy was 14.00 (interquartile range: 11.60-17.80) μmol/L. There was a significant positive association between plasma Hcy and PAD (per SD increment; OR: 1.13; 95% CI: 1.06-1.19). Patients in the upper plasma Hcy tertile (≥16.16 μmol/L) were associated with a 53% increased risk of PAD compared with patients in the lower tertile (<12.33 μmol/L) after adjustment for multiple potential confounders. Subgroup analyses showed the association between Hcy and PAD was robust among various strata. Among Chinese adults with hypertension, plasma Hcy is an independent risk factor for PAD. This finding may improve the risk stratification of PAD.

Fifteen-year clinical prognosis and cardiovascular or limb event associated with homocysteine levels in peripheral arterial disease

BACKGROUND

There are limited reports on the relationship between plasma homocysteine (Hcy) levels and long-term all-cause death (ACD), cardiovascular events, or limb events in patients with peripheral arterial disease (PAD). We examined the relationship between plasma Hcy levels and 15-year these events in PAD patients.

METHODS

We performed a prospective cohort study in 955 PAD patients. The patients were divided into four groups based on plasma Hcy levels with median (interquartile range). The endpoints were cumulative incidences of ACD, major adverse cardiovascular events (MACE), and MACE plus limb events (MACLE).

RESULTS

The incidences of ACD, MACE, and MACLE were correlated with plasma Hcy levels (P < 0.05). In multiple regression analysis, plasma Hcy had positive correlations with C-reactive protein (CRP), men, and critical limb ischemia (CLI) and negative correlations with estimated glomerular filtration rate (eGFR) and high-density lipoprotein cholesterol (p < 0.05). In Cox multivariate analysis, higher Hcy (HR 1.614, 95 % CI 1.229-2.119, p = 0.001), age, CRP, brain natriuretic peptide (BNP), D-dimer, lower body mass index, ankle brachial pressure index (ABI), serum albumin, eGFR, CLI, coronary heart disease (CHD), cerebrovascular disease, and diabetes were related to ACD; higher Hcy (HR 1.242, 95 % CI 1.004-1.535, p = 0.045), age, BNP, lower ABI, serum albumin, diabetes, and CHD were related to MACE; and higher Hcy (HR 1.290, 95 % CI 1.057-1.574, p = 0.012), BNP, lower ABI, serum albumin, CHD, and diabetes were related to MACLE (P < 0.05). Statins improved ACD, MACE, and MACLE (p < 0.01).

CONCLUSIONS

Plasma Hcy was a risk factor for 15-year ACD, MACE, and MACLE in patients with PAD.

Associations of Homocysteine, Folate, and Vitamin B12 with Osteoarthritis: A Mendelian Randomization Study

Homocysteine, inversely related to folate and vitamin B12, is an independent risk factor for several age-related disorders. However, little is known about the association of homocysteine and related vitamins with osteoarthritis (OA). This study aimed to elucidate the potential causal effects of homocysteine, folate, and vitamin B12 on site- and gender-specific OA by applying the two-sample Mendelian randomization (MR) approach. Genetically predicted homocysteine showed adverse effects on overall OA (95% confidence interval (CI): 1.044–1.155), knee OA (95% CI: 1.000–1.167), hip OA (95% CI: 1.057–1.297), and spine OA (95% CI: 1.017–1.216). Genetically predicted folate showed protective effects on overall OA (95% CI: 0.783–0.961) and spine OA (95% CI: 0.609–0.954). Folate (95% CI: 0.887–1.004) and vitamin B12 (95% CI: 0.886–1.009) showed a protective trend against knee OA. The patterns of associations were site and gender specific. In conclusion, homocysteine had adverse effects on OA, especially on OA at weight-bearing joints and in females. Folate and vitamin B12 had protective effects on OA. Homocysteine-lowering interventions may be a potential option in the treatment and prevention of OA.

Associations between Serum Folate Concentrations and Functional Disability in Older Adults

Folate may have beneficial effects on physical function through its antioxidant effect. Thus, we investigated the associations between serum folate and functional disability in older adults. Data from the National Health and Nutrition Examination Survey 2011–2018 were used. Serum folate included 5-methyltetrahydrofolate and total folate. Five domains of functional disability, including lower extremity mobility (LEM), instrumental activities of daily living (IADL), activities of daily living (ADL), leisure and social activities (LSA), and general physical activities (GPA), were self-reported. Multivariable-adjusted logistic regression models and restricted cubic splines were employed. 5-Methyltetrahydrofolate was inversely associated with IADL and GPA disability, and the multivariate-adjusted ORs (95% CIs) in the highest versus lowest quartiles were 0.65 (0.46–0.91) and 0.70 (0.50–0.96), respectively. The total folate was also inversely associated with IADL (OR quartile 4vs1 = 0.65, 95% CI: 0.46–0.90) and GPA (OR quartile 3vs1 = 0.66, 95% CI: 0.44–0.99) disability. The dose–response relationships showed a gradual decrease in the risk of IADL and GPA disability as serum folate increased. In the sex, age, BMI, and alcohol consumption subgroup analyses, we saw that the associations were primarily found in females, under 80 years old, normal weight, and non-drinkers. Sensitivity analyses further confirmed the robustness of our results. Our results indicated that serum folate concentrations were negatively associated with IADL and GPA disability, especially in females. In other subgroup analyses, we discovered that these negative associations were primarily prevalent in participants under 80 years old, normal weight, and non-drinkers.

Mid-Luteal Progesterone Is Inversely Associated with Premenstrual Food Cravings

It is not clear whether progesterone and estradiol associate with premenstrual food cravings, which significantly contribute to cardiometabolic adverse effects associated with obesity. We sought to investigate this question in the present study based on the prior literature showing a protective effect of progesterone on drug craving and extensive neurobiological overlaps between food and drug cravings. We enrolled 37 non-illicit drug- or medication-using women in the study to provide daily ratings of premenstrual food cravings and other symptoms across two-three menstrual cycles, based on which we classified them as premenstrual dysphoric disorder (PMDD) or control participants. In addition, the participants provided blood samples at eight clinic visits across the menstrual cycle. We aligned their mid-luteal progesterone and estradiol using a validated method which relies upon the peak serum luteinizing hormone and analyzed estradiol and progesterone using ultraperformance liquid chromatography tandem mass spectrometry. Hierarchical modeling, adjusted for BMI, showed a significant inverse effect of progesterone (p = 0.038) but no effect of estradiol on premenstrual food cravings. The association was not unique to PMDD or control participants. Results of research to date in humans and rodents showing that progesterone has dampening effects on the salience of the reinforcer translate to premenstrual food cravings.

Effect of Blood Homocysteine on the Outcome of Artificial Insemination in Women with Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is the major reason for women's low fertility and the most frequent endocrine disorder in women of childbearing age. Homocysteine is an amino acid that contains sulfur that has been negatively correlated with the reproductive outcome of polycystic women treated with IVF/ICSI. However, the impact of blood homocysteine levels on the outcome of artificial insemination in polycystic ovary syndrome women is unknown. The goal of this study is to examine the impact of serum homocysteine on the result of intrauterine insemination in females who have polycystic ovary syndrome (PCOS).

Methods

96 infertile women (129 cycles) treated with artificial insemination were collected, including 66 cases (87 cycles) in the case group (PCOS group) and 30 cases (42 cycles) in the control group (male factor infertility). The differences in general data amongst two groups, such as BMI, Hcy, and age, were compared. The case group has been classified into two groups based on serum Hcy level: LHcy group (Hcy < 15) and HHcy group (Hcy ≥ 15). The relationship among pregnancy and serum Hcy level outcome in PCOS women was compared.

Results

The PCOS group had substantially increased serum homocysteine levels in comparison to the control group (P = 0.019). Among PCOS women, the clinical pregnancy rates of artificial insemination in the HHcy group and LHcy group were 14.29% and 37.88%. The difference among the two groups was substantial (P = 0.044). Artificial insemination frequency, ovulation induction, BMI, infertility years, AMH, serum testosterone, HOME IR, TSH, TPOAb, hCG, daily follicle size, intimal thickness, and other factors did not differ greatly between the two groups.

Conclusion

Serum homocysteine levels are increased in women having PCOS. Their levels above the threshold will lower the clinical pregnancy rate of intrauterine insemination in PCOS women.

Threshold effect of plasma total homocysteine levels on cognitive function among hypertensive patients in China: A cross-sectional study

Background

Increased plasma total homocysteine (tHcy) is an influencing factor of cognitive impairment in the general population. However, studies on the relationship between the risk of cognitive impairment and plasma tHcy levels in patients with hypertension are limited. This study aimed to explore the association between plasma tHcy levels and cognitive function assessed by MMSE scores among hypertensive patients in China.

Methods

A total of 9,527 subjects from the Chinese Hypertension Registry Study participated in this study. Plasma tHcy levels were quantified by high-performance liquid chromatography using a fluorescence detector. Cognitive assessment was performed using the Mini-Mental State Examination (MMSE). Linear regression models, two piecewise linear regression models, and smoothing curve fitting were applied to determine the relationship between plasma tHcy levels and cognitive function.

Results

This analysis included 9,527 Chinese hypertensive adults. Based on the results of linear regression models, a negative relationship was identified between plasma tHcy levels and MMSE scores [beta coefficient (β) per standard deviation (SD) increase: −0.26, 95% confidence interval (CI) −0.35, −0.16, P < 0.001]. The fully adjusted smooth curve fitting presented a nonlinear between plasma tHcy levels and MMSE scores. The threshold effect analysis showed that the inflection point of tHcy was about 27.1 μmol/L. The effect size [β (95% CI)] per SD increase in plasma tHcy concentrations on MMSE scores was −0.93 (−1.24, −0.6) on the left side and −0.07 (−0.24, 0.10) on the right side of the inflection point (P-value for log-likelihood ratio (LLR) test was <0.001). Moreover, subgroup analyses revealed that sex could influence the negative association between plasma tHcy levels and MMSE scores up to a specific threshold (P-value for interaction <0.001). Linear regression models indicated that there was an enhanced inverse association between tHcy levels and MMSE scores in female patients with tHcy concentrations less than 26.9 μmol/L compared to male patients with tHcy concentrations less than 32.0 μmol/L.

Conclusions

Plasma tHcy levels had a threshold effect on MMSE scores among hypertensive patients in China. Increased plasma tHcy levels were independently inversely associated with cognitive decline among hypertensive patients with tHcy concentrations <27.1 μmol/L.

Relationship between homocysteine levels and post-stroke cognitive impairment in female and male population: from a prospective multicenter study

Background and Objectives:

To investigate the relationship between homocysteine levels and post-stroke cognitive impairment (PSCI) in Chinese female and male populations with minor acute ischemic stroke or transient ischemic attack.

Materials and methods:

A total of 1070 participants with clinically confirmed acute minor ischemic stroke or transient ischemic attack and baseline homocysteine information from a nationwide multicenter prospective registry study in China were included in this study. Of these, 919 patients had cognitive assessments at 3-month follow-ups and 584 participants had cognitive assessments at 12-month follow-ups. The incidence of PSCI was defined as a Montreal Cognitive Assessment score ≤22. The differences in homocysteine levels and the incidence of PSCI were compared between female and male populations. Relationships between homocysteine levels and the incidence of PSCI in female and male populations were analyzed using multiple logistic regression, respectively.

Results:

Females had lower baseline homocysteine levels than males. Compared to males, females had lower education levels, lower rates of smoking and alcohol intake, and higher rates of diabetes and hypertension. No relationship was observed between elevated homocysteine level and 3-month PSCI incidence in either females or males. After adjusting the confounders, elevated baseline homocysteine significantly increased the 12-month PSCI risk (odds ratio 3.28, 95% confidence interval 1.47–7.34, P = 0.004) in females, but not in males (odds ratio 0.86, 95% confidence interval 0.49–1.49, P = 0.586).

Conclusion:

Elevated homocysteine levels increased the 12-month PSCI risk in females, but not in males with minor acute ischemic stroke or transient ischemic attack.

Estradiol-17β inhibits homocysteine mediated damage by promoting H2 S production via upregulating CBS and CSE expression in human umbilical vein endothelial cells

Associated with reduced hydrogen sulfide (H₂ S) production in Hcy metabolic disorders, Plasma Hcy accumulation can bring about vascular dysfunction. Nevertheless, recently proposed therapies for vascular damage by estrogen could contribute to promoting endogenous hydrogen sulfide production. This study explores whether estrogen can come into play in protection in hyperhomocysteinemia and hypertensive patients at a population level, and then analyses the specific mechanism of estrogen protection in homocysteine (Hcy)-treated human umbilical vein endothelial cells (HUVECs) at the foundational level. A case-control study, conducted on 1277 female hypertension and non-hypertensive patients from Hunan Provincial People's Hospital, showed that the Hcy concentration of hypertensive patients emerged higher than that of healthy controls (P < .001), and that of estrogen was the reverse (P < .001). Estrogen had a negative correlation with systolic blood pressure and plasma Hcy concentration. HUVECs were treated with estrogen and Hcy in the basic experimental part, and 17β-estradiol (E2β) stimulated proliferation and inhibited damage in Hcy-treated umbilical vein endothelial cells. Treatment with Hcy dampens the expression of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) then cuts down H₂ S production in cultured HUVECs, however, E2β reverses this process. To sum up, we have demonstrated a significant correlation between estrogen, Hcy concentration and systolic blood pressure reduction, which is bound up with Hcy metabolism and endogenous hydrogen sulfide production. The role of E2β was further strengthened by CBS and the CSE inhibitor through overthrowing the change in hydrogen sulfide of Hcy-treated HUVECs.

Exploration of the risk factors of essential hypertension with hyperhomocysteinemia: A hospital-based study and nomogram analysis

OBJECTIVES

To explore the risk factors of essential hypertension with hyperhomocysteinemia (H-type hypertension) and design a nomogram to predict this risk.

METHODS

A hospital-based study was conducted on 1,712 individuals, including 282 patients with H-type hypertension, 105 patients with simple hypertension, 645 individuals with hyperhomocysteinemia, and 680 healthy controls. Logistic regression and nomogram models were applied to evaluate the risk factors.

RESULTS

Logistic regression showed that advanced age, male sex, high body mass index (BMI), high total cholesterol levels, high glucose levels, and high creatinine levels were risk factors of H-type hypertension in the healthy population and were integrated into the nomogram model. Advanced age, male sex, high BMI, high total cholesterol levels, and high glucose levels were shown to be risk factors of H-type hypertension in the hyperhomocysteinemia population. Male sex and high creatinine levels were shown to be risk factors of H-type hypertension in the hypertension population. Nomogram analysis showed that the total factor score ranged from 106 to 206, and the corresponding risk rate ranged from 0.05 to 0.95.

CONCLUSIONS

Men are more likely to have H-type hypertension, and advanced age, high BMI, high total cholesterol levels, and high glucose levels are risk factors of H-type hypertension in healthy and hyperhomocysteinemia populations. Furthermore, high creatinine level is a risk factor of H-type hypertension in healthy and hypertension populations. Nomogram models may be used to intuitively evaluate H-type hypertension risk and provide a basis for personalized interventions.

Homocysteine as a peripheral biomarker in bipolar disorder: A meta-analysis

Background:

Bipolar disorder (BD) is a psychiatric disorder with an uncertain aetiology. Recently, special attention has been given to homocysteine (Hcy), as it has been suggested that alterations in 1-carbon metabolism might be implicated in diverse psychiatric disorders. However, there is uncertainty regarding possible alterations in peripheral Hcy levels in BD.

Methods:

This study comprises a meta-analysis comparing serum and plasma Hcy levels in persons with BD and healthy controls. We conducted a systematic search for all eligible English and non-English peer-reviewed articles.

Results:

Nine cross-sectional studies were included in the meta-analyses, providing data on 1547 participants. Random-effects meta-analysis showed that serum and plasma levels of Hcy were increased in subjects with BD in either mania or euthymia when compared to healthy controls, with a large effect size in the mania group (g= 0.98, 95% CI: 0.8–1.17,P< 0.001,n= 495) and a small effect in the euthymia group (g= 0.3, 95% CI: 0.11–0.48,P= 0.002,n= 1052).

Conclusions:

Our meta-analysis provides evidence that Hcy levels are elevated in persons with BD during mania and euthymia. Peripheral Hcy could be considered as a potential biomarker in BD, both of trait (since it is increased in euthymia), and also of state (since its increase is more accentuated in mania). Longitudinal studies are needed to clarify the relationship between bipolar disorder and Hcy, as well as the usefulness of peripheral Hcy as both a trait and state biomarker in BD.

Sex differences in the prevalence and clinical correlates of hyperhomocysteinemia in patients with bipolar disorder

OBJECTIVE

Sex differences in bipolar disorder are well recognized but little attention has been paid to sex differences in homocysteine or hyperhomocysteinemia in bipolar patients. This study compared gender differences in homocysteine levels and rates of hyperhomocysteinemia in Chinese inpatients with bipolar disorder.

METHODS

A total of 198 BD patients and 84 healthy controls were enrolled. The Young Mania Rating Scale, Hamilton Depression Rating Scale, and the Clinical Global Impressions-Severity scale were used to assess the affective symptomatology. Fasting plasma Hcy levels were measured by high-performance liquid chromatography.

RESULTS

Men had higher homocysteine levels than women and the prevalence of hyperhomocysteinemia in male patients was approximately twice that in female patients. Logistic regression analyses showed that HHcy was associated with less frequent use of valproate in males and being overweight in females. Further correlation analysis and multivariate regression analysis demonstrated that Hcy levels were inversely correlated with valproate treatment in men and positively associated with overweight in women.

CONCLUSIONS

In bipolar patients, there are significant differences between sexes in the levels of homocysteine and prevalence of hyperhomocysteinemia. This appears to be associated with lower prevalence of valproate prescribing in men and with being overweight in women.

Homocysteine-mediated gender-dependent effects of prenatal maternal depression on motor development in newborn infants

BACKGROUND

The present study aimed to determine whether there were gender differences in the effects of prenatal maternal depression on motor development in newborn infants, and further to explore the role of plasma homocysteine in the delayed motor development in male newborn infants following prenatal maternal depression.

METHODS

The term pregnant women within 37-42 weeks of gestation were assessed depressive symptoms by Hamilton Rating Scale for Depression. According to the gender of the newborn infants, all the subjects were divided into four groups: female control group (n = 45), male control group (n = 47), female depression group (n = 50), male depression group (n = 60). Motor development in newborn infants were assessed by Neonatal Behavioral Assessment Scale. Plasma homocysteine concentrations both in mothers and newborn infants were measured by enzymatic cycling assay.

RESULTS

There were the worse scores of the items of motor development and significantly higher plasma homocysteine concentrations  in the male newborn infants of depression group than those of the female depression group and female control group, male control group, respectively. Plasma homocysteine concentrations significantly correlated with the items of motor development in all newborn infants, including the depression group and control group.

LIMITATIONS

We should further explore homocysteine-mediated gender-dependent effects of prenatal maternal depression on motor development in newborn infants in the long-term follow-up.

CONCLUSIONS

Prenatal maternal depression could result in delayed motor development in male newborn infants, but not female newborn infants. Plasma homocysteine may mediate gender-dependent effects of prenatal maternal depression on motor development in newborn infants.

Homocysteine Level Predicts Response to Dual Antiplatelet in Women With Minor Stroke or Transient Ischemic Attack: Subanalysis of the CHANCE Trial

OBJECTIVES

To investigate the relationship of homocysteine levels with the efficacy and safety of dual antiplatelet therapy in female and male patients. Approach and Results: The CHANCE trial (Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events) randomized patients with acute minor ischemic stroke or high-risk transient ischemic attack to clopidogrel plus aspirin or aspirin alone from October 1, 2009, to July 30, 2012, in China. A subgroup of 3044 consecutive patients with baseline homocysteine levels from 73 (64%) prespecified clinical sites was analyzed. Participants were grouped by sex. Primary outcome was stroke recurrence within 90 days. Secondary outcomes consisted of composite vascular events and independent living or death. Safety outcome was any bleeding. Cox proportional-hazards models were used to assess the interaction of homocysteine levels with randomized antiplatelet therapy on efficacy and safety outcomes. A significant interaction between homocysteine levels and the randomized antiplatelet therapies was found on recurrent stroke after adjustment for confounding factors in women (P=0.010) but not in men (P=0.595). Compared with aspirin alone, clopidogrel plus aspirin significantly reduced the risk of recurrent stroke in women without elevated homocysteine levels (adjusted hazard ratio, 0.459 [95% CI, 0.271-0.776]; P=0.004). Such benefit disappeared in female patients with increased homocysteine level. No significant interaction on functional outcome or bleeding rate was observed.

CONCLUSIONS

Homocysteine could be a potential biomarker to discriminate the effects of dual and single antiplatelet therapy in female patients with minor ischemic stroke or high-risk transient ischemic attack.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00979589.

Association between serum homocysteine level and unexplained infertility in in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI): A retrospective, hospital-based, case-control study

Background

Lower serum homocysteine (Hcy) levels are found to correlate with a better chance of clinical pregnancy and better embryo grades in assisted reproductive technology (ART). However, there is little knowledge on the association between Hcy level and unexplained infertility until now.

Methods

A total of 388 infertile women undergoing IVF/ICSI treatments were recruited, including 129 women with unexplained causes (case group) and 259 women with known causes (control group), and the case group was further divided into subgroups A (≤8 μmol/L), B (>8 and <15 μmol/L), and C (≥15 μmol/L) based on the serum Hcy level. The associations between serum Hcy level and IVF/ICSI pregnancy outcomes were examined in infertile women with unknown causes.

Results

A significantly higher serum Hcy level was measured in the case group than in the control group (P = .008). Subgroup analysis revealed a significant difference in the total number of oocytes retrieved among subgroups A, B, and C (P = .031), and no significant difference was seen among these three groups in terms of age, BMI, E₂ level on the hCG day, number of M‐II oocytes, number of fertilized oocytes, or total number of high‐quality embryos (P > .05). Spearman correlation analysis revealed a negative correlation between serum Hcy level and total number of oocytes retrieved (r = −.406, P = .019). Univariate and multivariate linear regression analyses revealed that serum Hcy level had no correlations with any IVF/ICSI outcomes.

Conclusion

Serum Hcy level has no associations with IVF/ICSI pregnancy outcomes.

Metabolism of Glutathione S-Conjugates: Multiple Pathways

Many potentially toxic electrophilic xenobiotics and some endogenous compounds are detoxified by conversion to the corresponding glutathione S-conjugate, which is metabolized to the N-acetylcysteine S-conjugate (mercapturate) and excreted. Some mercapturate pathway components, however, are toxic. Bioactivation (toxification) may occur when the glutathione S-conjugate (or mercapturate) is converted to a cysteine S-conjugate that undergoes a β-lyase reaction. If the sulfhydryl-containing fragment produced in this reaction is reactive, toxicity may ensue. Some drugs and halogenated workplace/environmental contaminants are bioactivated by this mechanism. On the other hand, cysteine S-conjugate β-lyases occur in nature as a means of generating some biologically useful sulfhydryl-containing compounds.

Hyperhomocysteinaemia is an independent risk factor for peripheral arterial disease in a Chinese Han population

BACKGROUND AND AIMS

Hyperhomocysteineamia (HHcy) has long been suggested as a risk factor for atherosclerosis. However, the association between HHcy and peripheral arterial disease (PAD) is still controversial. There is a lack of research on this topic in the Chinese population. This study aims to provide further results.

METHODS

240 PAD patients and 240 control subjects were evaluated for both serum total homocysteine levels and ankle brachial indexes (ABIs). Multivariable logistic regression models were used to estimate the association between HHcy and the risk of developing PAD. Interaction and stratified analyses were conducted according to age, sex, smoking status, drinking status, and histories of chronic disease.

RESULTS

The multivariate logistic regression analyses revealed that the risk of PAD was significantly associated with serum homocysteine levels. The interaction analysis showed no interactive role in the association between HHcy and PAD, indicating that homocysteine was associated with PAD independently of classical vascular risk factors.

CONCLUSIONS

In conclusion, HHcy is an independent risk factor for PAD in the Chinese Han population. A prospective and randomized clinical trial of homocysteine lowering therapy in the Chinese population is needed to assess the causal nature of the relationship.

Application of adaptive neuro-fuzzy inference systems (ANFIS) to delineate estradiol, glutathione and homocysteine interactions

The rationale of the current study was to elucidate the contributing factors for the gender-based differences in total plasma homocysteine levels. A total of 413 subjects comprising of 293 men and 120 women were enrolled for the study. Chemiluminescence technology for vitamin B₁₂, folate and total plasma homocysteine; ELISA for estradiol and 8-oxo-2-deoxyguanosine; Ellman's method for total glutathione; and PCR-RFLP analysis for the detection of methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism were employed. No statistically significant differences were observed between the men and women in the distribution of age (p = 0.82), vitamin B₁₂ (p = 0.23), folate (p = 0.36) and MTHFR C677T polymorphism (p = 0.35). However, the total plasma homocysteine levels were higher in men compared to women (28.4 ± 17.9 vs. 20.6 ± 13.6 μmol/L, p < 0.0001). In order to explain this gender differences in homocysteine, adaptive neuro-fuzzy inference systems (ANFIS) were developed to understand trivariate interactions among estradiol, glutathione and homocysteine. In the presence of adequate estradiol levels, inverse association was observed between glutathione and homocysteine. This association is lost when estradiol levels were inadequate. Estradiol was found to quench homocysteine mediated oxidative DNA damage. Irrespective of gender, combined deficiency of vitamin B₁₂ and folate showed positive association with hyperhomocysteinemia and vice versa. Homocysteine reduction in response to vitamin status varied according to gender with men responding to folate and women responding to B₁₂. To conclude, gender-differences in homocysteine are attributable estradiol mediated lowering of homocysteine that prevents inactivation of glutathione mediated oxidative defense in women.

Association between premature ovarian failure, polymorphisms in MTHFR and MTRR genes and serum homocysteine concentration

This study investigated the association between premature ovarian failure (POF), MTHFR C677T/A1298C and MTRR A66G genotypes and serum homocysteine (Hcy) concentration. A prospective study was conducted in Chinese women, which included POF patients (n = 180) and controls (n = 195). Peripheral blood samples were used to determine MTHFR C677T/A1298C and MTRR A66G genotypes, and serum Hcy and sex hormone concentrations. Results showed that serum Hcy concentrations of POF patients were significantly higher than those of controls (P < 0.0001). In POF patients, serum Hcy concentrations were significantly correlated with oestradiol and FSH concentrations (r = -0.174, P = 0.037 and r = +0.238, P = 0.006, respectively). There were no significant differences in the distributions of MTHFR C677T/A1298C or MTRR A66G genotypes between the two groups. However, these genetic variants influenced serum Hcy concentrations in POF patients, especially for MTRR 66 AA/AG/GG genotypes, which were significantly correlated with the patients' Hcy concentrations (τ = 0.166, P = 0.033). These results suggest that serum Hcy concentrations in Chinese POF patients are increased and correlated with serum oestradiol/FSH concentrations. In conclusion, MTHFR C667T/A1298C and MTRR A66G genotypes are not associated with POF development, but they affect the patients' serum Hcy concentrations.

Identification of conserved hepatic transcriptomic responses to 17β-estradiol using high-throughput sequencing in brown trout

Estrogenic chemicals are major contaminants of surface waters and can threaten the sustainability of natural fish populations. Characterization of the global molecular mechanisms of toxicity of environmental contaminants has been conducted primarily in model species rather than species with limited existing transcriptomic or genomic sequence information. We aimed to investigate the global mechanisms of toxicity of an endocrine disrupting chemical of environmental concern [17β-estradiol (E2)] using high-throughput RNA sequencing (RNA-Seq) in an environmentally relevant species, brown trout (Salmo trutta). We exposed mature males to measured concentrations of 1.94, 18.06, and 34.38 ng E2/l for 4 days and sequenced three individual liver samples per treatment using an Illumina HiSeq 2500 platform. Exposure to 34.4 ng E2/L resulted in 2,113 differentially regulated transcripts (FDR < 0.05). Functional analysis revealed upregulation of processes associated with vitellogenesis, including lipid metabolism, cellular proliferation, and ribosome biogenesis, together with a downregulation of carbohydrate metabolism. Using real-time quantitative PCR, we validated the expression of eight target genes and identified significant differences in the regulation of several known estrogen-responsive transcripts in fish exposed to the lower treatment concentrations (including esr1 and zp2.5). We successfully used RNA-Seq to identify highly conserved responses to estrogen and also identified some estrogen-responsive transcripts that have been less well characterized, including nots and tgm2l. These results demonstrate the potential application of RNA-Seq as a valuable tool for assessing mechanistic effects of pollutants in ecologically relevant species for which little genomic information is available.

Hyperhomocysteinemia independently associated with the risk of hypertension: a cross-sectional study from rural China

This study was designed to investigate the current prevalence of hyperhomocysteinemia (Hhcy) and its association with hypertension in rural adults of Northeast China. A cross-sectional study was performed in subjects aged⩾35 years in a general Chinese population. Demographic data, laboratory examination of traditional cardiovascular risk factors and self-reported information on lifestyle factors, such as physical activities, current smoking and drinking status, dietary habits and familial factors were collected by trained personnel. A total of 7130 participants (3317 men and 3813 women) were included in this study and the mean Hhcy level of the whole population was 17.39±12.34 mmol l(-1), which was 20.99±14.83 mmol l(-1) in males and 14.19±8.51 mmol l(-1) in females, respectively. Prevalence of Hhcy in total population was 41.3%. Stratified by gender, the prevalence of Hhcy was higher in males than in females (59.0 vs 25.8%, P<0.05). After adjustment for conventional risk factors including age, salt intake, smoking, body mass index, diabetes, dyslipidemia, activity time and family history, multiple logistic regression analysis showed that Hhcy was independently associated with the risk of hypertension in males (odds ratio (OR)=1.501, 95% confidence interval (CI): 1.012-2.227; P<0.001), but not in females in this population (OR=1.182; 95% CI, 0.993-1.407; P=0.060). In conclusion, a high prevalence of Hhcy in the general adult population of rural northeast China was detected and Hhcy may be a risk factor for hypertension, particularly in males.

Homocysteine, Ischemic Stroke, and Coronary Heart Disease in Hypertensive Patients

Background and Purpose—

Total homocysteine level (tHcy) is a risk factor of ischemic stroke (IS) and coronary heart disease. However, the results are conflicting and mainly focused on healthy individuals in developed countries.

Methods—

A prospective, population-based cohort study was conducted among 5935 participants from 60 communities in the city of Shenzhen, China. A Cox regression analysis was applied to evaluate the contribution of tHcy to the risk of IS and coronary heart disease. The effect of folic acid supplementation on tHcy levels was also evaluated among 501 patients with essential hypertension, who received an average of 2.5 years of folic acid supplementation.

Results—

After adjustment for confounding factors, the hazard ratios (95% confidence intervals) of IS caused by hyperhomocysteinemia were 2.18 (1.65–2.89), 2.40 (1.56–3.67), and 2.73 (1.83–4.08) in the total, male, and female participants, respectively. Compared with normal levels of tHcy (<15 μmol/L), the hazard ratios (95% confidence intervals) for IS in the highest tHcy category (≥30 μmol/L) were 4.96 (3.03–8.12), 6.11 (3.44–10.85), and 1.84 (0.52–6.46) in the total, males, and females participants, respectively. However, we did not observe a significant relationship between tHcy and the risk of coronary heart disease. The 2.5 years of folic acid supplementation reduced tHcy levels by 6.7 μmol/L (27.92%) in patients with essential hypertension.

Conclusions—

Hyperhomocysteinemia in Chinese hypertensive patients is significantly associated with IS risk but not coronary heart disease susceptibility, and folic acid supplementation can efficiently reduce tHcy levels.

Elevated plasma homocysteine level is associated with ischemic stroke in Chinese hypertensive patients

BACKGROUND

Accumulating data suggest that hyperhomocysteinemia is associated with the risk of ischemic stroke (IS) and coronary heart disease (CHD) in the general population, but the relationship remains unclear in hypertensive patients. We examined the association of total homocysteine (tHcy) with IS and CHD in hypertensive patients.

METHODS

A total of 5935 Chinese hypertensive patients were recruited in a community-based cross-sectional study from 60 communities in Shenzhen, China. Plasma tHcy was quantitatively measured using the enzyme cycle method. Conventional risk factors for IS and CHD were obtained through questionnaire interviews and physical examinations. We included cerebral infarction, embolism and small-vessel disease as IS; and myocardial infarction, angina pectoris, coronary revascularization, and cardiac arrest as CHD. IS and CHD were retrospectively adjudicated by specialists via interviews, hospital records or relevant tests.

RESULTS

Significantly higher values of tHcy were observed in IS patients than in non-IS controls among both men and women. Greater tHcy level was dose dependently associated with an increased risk of IS presence in women, men and them combined (p-trend: 0.002, 3.8×10(-4) and 0.001). The odds ratios (95% CI) of IS for tHcy ≥30 (vs. <15) μmol/L were 2.84 (1.73-4.34) in men, 4.41 (1.62-9.15) in women, and 2.86 (1.72-4.75) in their combination after adjusting for other main risk factors of IS. We did not find any significant association between tHcy and presence of CHD after the adjustment for covariates.

CONCLUSIONS

Plasma homocysteine level is positively associated with the presence of IS, but not CHD, in Chinese hypertensive patients.

Adaptive developmental plasticity in methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism limits its frequency in South Indians

Methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism shows considerable heterogeneity in its distribution in humans worldwide. The current study was conducted to investigate whether this polymorphism exhibited adaptive developmental plasticity in the control of the TT-genotype frequency. We screened 1,818 South Indian subjects (895 males and 923 females) for MTHFR C677T polymorphism using PCR-restriction fragment length polymorphism approach. MTHFR 677T-allele frequency in males and females was 9.1 and 11.0%, respectively. Compared to females, males had lower frequency of TT-genotype [odds ratio 0.31, 95% confidence interval (CI) 0.08-1.01]. The frequency of MTHFR 677T-allele was highest in the age group of 20-40 years and it gradually decreased from 40-60 to 60-80 years (P trend<0.0001). MTHFR 677TT-genotype was associated with 7.02-folds (95% CI: 2.12-25.63, P<0.0001) cumulative risk for recurrent pregnancy loss (RPL), neural tube defects (NTDs) and deep vein thrombosis (DVT). Linear regression model suggested that male gender exhibited increased homocysteine levels by 9.35 μmol/L while each MTHFR 677T-allele contributed to 4.63 μmol/L increase in homocysteine. Plasma homocysteine showed inverse correlation with dietary folate (r=-0.17, P<0.0001), B2 (r=-0.14, P<0.0001) and B6 (r=-0.07, P=0.03). Examination of the spontaneously aborted fetuses (n=35) showed no significant association of fetal genotype on its in utero viability. From the current study, it was concluded that C677T seemed to have acquired adaptive developmental plasticity among South Indians due to environmental influences thus contributing to hyperhomocysteinemia and its associated complications such as RPL, NTDs, DVT, etc.