Prospective study of serum total homocysteine concentration and risk of stroke in middle-aged British men

Endothelial Dysfunction Does Not Occur after Acute, Elevated Homocysteine Exposure of the Lumen of the Iliac Artery of the Anaesthetised Pig

INTRODUCTION

Elevated luminal homocysteine has been linked with cardiovascular disease; however, whether there is a direct effect of homocysteine on blood vessel endothelium is not clear. In this study, the acute effect of luminal homocysteine on iliac artery endothelial function was assessed in the anaesthetised pig.

METHODS

Hyperhomocysteinaemic blood was injected into an occluded segment of the iliac in the anaesthetised pig for 20 min, and the effect on atrial diameter during the occlusion and during the reactive hyperaemia assessed.

RESULTS

No significant changes in arterial diameter or pressure were observed during the incubation period at homocysteine concentrations of 10, 20, 40 and 100 µM. There was also no difference in the magnitude of the iliac diameter increase in the response to reactive hyperaemia when the incubation period was completed.

CONCLUSION

There is no evidence of endothelial dysfunction in response to an acute 20-min elevation in homocysteine in an intact conduit artery.

Elevated Blood Homocysteine Increases the Risk of Incident Motoric Cognitive Risk Syndrome: A Two-Cohort Study

BACKGROUND

Motoric Cognitive Risk (MCR) syndrome, a predementia syndrome characterized by cognitive complaints and slow gait, may have an underlying vascular etiology. Elevated blood levels of homocysteine, a known vascular risk factor, have been linked to physical and cognitive decline in older adults, though the relationship with MCR is unknown. We aimed to identify the association between homocysteine and MCR risk.

METHODS

We examined the association between baseline homocysteine levels and incident MCR using Cox proportional hazard models in 1826 community-dwelling older adults (55% women) from 2 cohorts (Einstein Aging Study [EAS] and Quebec Longitudinal Study on Nutrition and Successful Aging [NuAge]). We calculated hazard ratios (HR) with 95% confidence intervals (CI), for each cohort as well as stratified by sex and vascular disease/risk factors.

RESULTS

Median follow-up time was 2.2 years in EAS and 3.0 years in NuAge. Individuals with elevated baseline homocysteine levels (>14 µmol/L) had a significantly higher risk of incident MCR compared to those with normal levels in NuAge (HR 1.41, 95% CI: 1.01-1.97, p = .04), after adjusting for covariates. Our exploratory stratified analyses found that these associations were significant only in men with vascular disease/risk factors.

CONCLUSIONS

Higher blood homocysteine levels are associated with an increased risk of developing MCR in older adults, particularly in men with vascular disease or vascular risk factors.

Associations between homocysteine and B vitamins and stroke: a cross-sectional study

Objective

Homocysteine (Hcy) is a predictor for stroke. B vitamins are required for the metabolism of Hcy. We designed a study to investigate the associations of plasma Hcy and B vitamins with the prevalence of stroke in adults.

Methods

A total of 8,371 adults were included in the National Health and Examination Survey (NHANES) between 2003-2006 in the United States. Multivariate regression analysis and smooth curve fitting were conducted to evaluate the associations of stroke prevalence with Hcy, folate, vitamin B6, and B12. A segmented regression model was used to analyze the threshold effects. Sample weights were calculated to ensure the results' generalizability.

Results

The mean age of all participants was 46.43 years (51.8% women), and the prevalence of stroke was 2.72%. A nonlinear and positive association was found between plasma Hcy levels and the prevalence of stroke. Furthermore, L-shaped associations were found between plasma vitamin B6 and folate levels and stroke, with the turning point at 65.2 nmol/L for vitamin B6 and 26 nmol/L for folate, respectively. Vitamin B12 revealed a U-shaped relationship with stroke, with the turning points at 492.98 pmol/L for vitamin B12.

Conclusion

Non-linear associations of plasma Hcy and B vitamins levels with stroke prevalence were found in American adults. These associations may have an implication that higher plasma Hcy levels should be reduced, and plasma vitamin B6, vitamin B12 and folate levels should be moderately improved in stroke prevention. Future studies are needed to verify the causality of these associations and elucidate the underlying mechanisms.

Association of Homocysteine with Acute Stroke and Its Subtypes in the Chinese Population

Purpose

Homocysteine (Hcy) is recognized as a risk factor for stroke. Our study examined the relationship between plasma Hcy levels and stroke, along with its subtypes, among Chinese patients who experienced an acute stroke episode.

Patients and Methods

We retrospectively enrolled patients with acute stroke and age- and sex-matched healthy controls admitted to the First Affiliated Hospital of Xi'an Jiaotong University from October 2021 to September 2022. Ischemic stroke subtypes were classified using the modified TOAST criteria. Multivariate logistic regression models were employed to probe the associations of plasma Hcy levels with total stroke, ischemic stroke and its subtypes, and hypertensive intracerebral hemorrhage (HICH), and the correlation between plasma Hcy levels and the National Institute of Health Stroke Scale (NIHSS).

Results

The mean age of the total group was 63 years, with women representing 30.6% (246 individuals). Elevated Hcy levels were significantly associated with total stroke (OR 1.054, 95% CI: 1.038-1.070), HICH (OR 1.040, 95% CI: 1.020-1.060), ischemic stroke (OR 1.049, 95% CI: 1.034-1.065), and the TOAST subtypes of ischemic stroke in large-artery atherosclerosis (LAA) (OR 1.044, 95% CI: 1.028-1.062) and small-artery occlusion (SAO) (OR 1.035, 95% CI: 1.018-1.052), but not with cardioembolic (CE) stroke. Moreover, only in the case of SAO stroke were the Hcy levels positively correlated with the NIHSS score (B=0.030, 95% CI: 0.003-0.056, P=0.030).

Conclusion

Plasma Hcy levels were found to be positively correlated with the risk of stroke, particularly in the context of LAA, SAO stroke, and HICH. Additionally, Hcy levels demonstrated a positive correlation with stroke severity in patients presenting with SAO stroke. These findings suggest potential clinical implications in stroke prevention, particularly for ischemic stroke (LAA, SAO subtypes) and HICH by employing homocysteine-lowering therapies. Future investigations are warranted to fully elucidate these associations.

Homocysteine-Potential Novel Diagnostic Indicator of Health and Disease in Horses

Homocysteine is an endogenous, non-protein sulfuric amino acid, an intermediate metabolite formed by the methionine transmethylation reaction. Its elevated serum concentration in humans, hyperhomocysteinemia, is a sensitive indicator and a risk factor for coagulation disorders, cardiovascular diseases and dementia. However, the role of homocysteine in veterinary species has not been unequivocally established. Although some research has been conducted in dogs, cats, cattle and pigs, relatively few studies on homocysteine have been conducted in horses. So far, it has been established in this species that homocysteine has an atherogenic effect, plays a role in early embryo mortality and is responsible for the induction of oxidative stress. These preliminary findings support establishing a reference range in a normal population of horses, including horses in training and merit further investigations into the role of this amino acid in health and disease in this species.

The Role of Potential Oxidative Biomarkers in the Prognosis of Acute Ischemic Stroke and the Exploration of Antioxidants as Possible Preventive and Treatment Options

Ischemic strokes occur when the blood supply to a part of the brain is interrupted or reduced due to arterial blockage, and it often leads to damage to brain cells or death. According to a myriad of experimental studies, oxidative stress is an important pathophysiological mechanism of ischemic stroke. In this narrative review, we aimed to identify how the alterations of oxidative stress biomarkers could suggest a severity-reflecting diagnosis of ischemic stroke and how these interactions may provide new molecular targets for neuroprotective therapies. We performed an eligibility criteria-based search on three main scientific databases. We found that patients with acute ischemic stroke are characterized by increased oxidative stress markers levels, such as the total antioxidant capacity, F2-isoprostanes, hydroxynonenal, total and perchloric acid oxygen radical absorbance capacity (ORACTOT and ORACPCA), malondialdehyde (MDA), myeloperoxidase, and urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine. Thus, acute ischemic stroke is causing significant oxidative stress and associated molecular and cellular damage. The assessment of these molecular markers could be useful in diagnosing ischemic stroke, finding its causes, predicting its severity and outcomes, reducing its impact on the cellular structures of the brain, and guiding preventive treatment towards antioxidant-based therapy as novel therapeutic alternatives.

Association Between Interpregnancy Interval and Risk of Preterm Birth and Its Modification by Folate Intake: The Japan Environment and Children's Study

BACKGROUND

Both short and long interpregnancy intervals (IPIs) have been associated with risk of preterm birth, but the evidence is limited in Asians. It is also uncertain whether the association is modified by dietary folate intake or folic acid supplementation during pregnancy. Thus, we examined associations between IPI and risk of preterm birth and effect modification of those associations by dietary intake of folate and supplementation with folic acid on the basis of a nationwide birth cohort study.

METHODS

Among 103,062 pregnancies registered in the Japan Environment and Children's Study, 55,203 singleton live-birth pregnancies were included in the analysis. We calculated IPI using birth date, gestational age at birth of offspring, and birth data of the latest offspring. Odds ratios (ORs) and 95% confidence intervals (CIs) of the risk of preterm birth were estimated according to IPI categories.

RESULTS

Both <6-month and ≥120-month IPIs were associated with an increased risk of preterm birth, compared with an 18-23-month IPI. The multivariable ORs were 1.63 (95% CI, 1.30-2.04) for <6-month and 1.41 (95% CI, 1.11-1.79) for ≥120-month IPIs. These associations were confined to women with inadequate intake of dietary folate and folic acid supplementation during pregnancy. Multivariable ORs were 1.76 (95% CI, 1.35-2.29) for <6-month IPI and 1.65 (95% CI, 1.24-2.19) for ≥120-month IPI.

CONCLUSION

Both <6-month and ≥120-month IPIs were associated with an increased risk of preterm birth. These higher risks were confined to women with inadequate intake of dietary folate and folic acid supplementation during pregnancy.

Evaluation of (sdLDLc*HCYc)/HDLc ratio in clinical auxiliary diagnosis of primary cerebral infarction

BACKGROUND

Timely detection of cerebral infarction is of vital importance in planning intervention effect of rapid rehabilitation. The clinical auxiliary diagnosis value of single biomarker, including small dense low-density lipoprotein concentration (sdLDLc), homocysteine concentration (HCYc) and high-density lipoprotein cholesterol concentration (HDLc) for cerebral infarction has been confirmed by many studies. Whether the use of three biomarkers in combination by calculating (sdLDLc*HCYc)/HDLc ratio could improve the diagnosis ability for primary cerebral infarction remains to be unclear. In the present study, we conducted a cross-sectional study to evaluate the value of (sdLDLc*HCYc)/HDLc ratio in clinical auxiliary diagnosis of primary cerebral infarction.

METHODS

A total of 583 participants, including 299 healthy participants as control group and 284 participants diagnosed with first cerebral infarction as experiment group, were included in this respective study. The serum sdLDLc, HDLc and HCYc were measured by peroxidase method, enzyme-linked immunosorbent assay and an enzymatic method, respectively.

RESULTS

The average concentration of sdLDL and HCY (0.69 ± 0.29 mmol/L and 18.14 ± 6.62 μmol/L) in experiment group was significantly higher than those in the control group (0.55 ± 0.22 mmol/L and 10.77 ± 2.67 μmol/L, P < 0.05). However, the average concentration of HDL (1.47 ± 0.25 mmol/L) in the control group was higher than that in the experiment group (1.33 ± 0.28 mmol/L, P < 0.05). Spearman correlation coefficient showed the three indicators are independent of each other. The positive predictive value of (sdLDLc*HCYc)/HDLc ratio (61.27%, 95% CI: 55.31-66.92) is higher than that in single biomarker (sdLDLc: 6.69 95% CI: 4.19-10.42, HCYc: 38.38%, 95% CI: 32.75-44.33, HDLc: 3.87%, 95% CI: 2.05-7.02). Receiver-operating characteristic curve (ROC) analysis illustrated that predictive power of (sdLDLc*HCYc)/HDLc was higher than single biomarker, including sdLDLc, HCYc and HDLc, in primary cerebral infarction.

CONCLUSIONS

Therefore, (sdLDLc*HCYc)/HDLc ratio might be a better new indicator in clinical auxiliary diagnosis of primary cerebral infarction, which could be contributed to predicting cerebral infarction occurrence and provide a scientific basis for early prevention.

Comparison of clinical profiles and associated factors for acute myocardial infarction among young and very young patients with coronary artery disease

BACKGROUND

This study aimed to compare the profiles of young and very young patients with coronary artery disease (CAD) and explore the factors associated with acute myocardial infarction (AMI) based on age.

METHODS

Young CAD patients aged between 18 and 44 years diagnosed by angiography were enrolled retrospectively. They were divided into two groups according to age: young CAD was defined as patients aged between 36 and 44 years, and very young CAD was defined as patients aged between 18 and 35 years. Demographic and clinical characteristics of the patients were collected.

RESULTS

In total, 9286 patients were included in the final database. Most were assigned to the young CAD group (86.5%), and 1250 (13.5%) had very young CAD. Most demographic and clinical characteristics of the young and very young patients with CAD differed significantly. The proportion of patients with CAD in the total population increased with age, whereas the incidence of AMI showed a decreasing trend. A previous percutaneous coronary intervention (PCI) was negatively associated with AMI. Dyslipidemia, current smoking, and hyperhomocysteinemia were positively associated with AMI in the overall and young population with CAD.

CONCLUSIONS

The clinical profiles and factors associated with AMI in CAD patients of different ages were significantly different. Lifestyle-related factors were significantly associated with AMI in young patients with CAD.

Homocysteine is associated with higher risks of ischemic stroke: A systematic review and meta-analysis

BACKGROUND

High levels of homocysteine (Hct) have been associated with great risks of ischemic stroke. However, some controversy still exists. We performed a systematic review and meta-analysis to compare the levels of Hct between patients with ischemic stroke and controls.

METHODS

We performed a systematic literature search for articles reporting Hct levels of patients with occurrence of ischemic stroke. We employed a random-effects inverse-variance weighted meta-analytical approach in order to pool standardized mean differences, with estimation of τ2 through the DerSimonian-Laird method.

RESULTS

The initial search yielded 1361 studies. After careful analysis of abstracts and full texts, the meta-analysis included data from 38 studies, which involved almost 16 000 stroke events. However, only 13 studies reported means and standard deviations for cases and controls, and therefore were used in the meta-analysis. Those studies presented data from 5002 patients with stroke and 4945 controls. Standardized mean difference was 1.67 (95% CI 1.00-2.25, P < 0.01), indicating that Hct levels were significantly larger in patients with ischemic stroke compared to controls. Between-study heterogeneity was very large (I2 = 99%), particularly because three studies showed significantly large mean differences.

CONCLUSION

This meta-analysis shows that patients with ischemic stroke have higher levels of Hct compared to controls. Whether this is a modifiable risk factor remains to be assessed through larger prospective cohorts.

Homocysteine, Vitamins B6, B12, and Folate and the Risk of Ischemic and Hemorrhagic Stroke: A Case-control Study from Northeast India

Background

Stroke is a major leading global health complication. Identification and management of risk factors associated with stroke can help in prior detection, prevention, and improvement in patient care.

Purpose

To investigate the prevalence of hyperhomocysteinemia (HHcy) and Vitamins B6, B12, and folate deficiency in stroke patients and also to assess other risk factors associated with ischemic and hemorrhagic stroke.

Methods

Detail history of all the subjects in the study including history of hypertension, anemia, fasting glucose, carotid artery thickness, smoking, alcohol, and dietary intake was recorded. Standard assays for homocysteine (Hcy), Vitamins B6, B12, and folate estimation were done. Lipid and renal profile tests were also performed. The prevalence and odds of having HHcy, Vitamins B6, B12, and folate deficiency, and other risk factors in ischemic and hemorrhagic stroke patients were evaluated. Student’s t-tests and chi-square tests were done for statistical validation of the data.

Results

Prevalence of HHcy and Vitamins B6, B12, and folate deficiency was not observed in ischemic cases. HHcy and folate deficiency was found to be prevalent in hemorrhagic stroke patients. The odds that a person with HHcy and folate deficiency has hemorrhagic stroke was found to be significantly high.

Conclusion

In our study, high Hcy and low folate levels emerged as risk factors for hemorrhagic stroke.

The Mutual Relationship among Cardiovascular Diseases and COVID-19: Focus on Micronutrients Imbalance

Micronutrients are ions and vitamins humbly required by the human body. They play a main role in several physiological mechanisms and their imbalance is strongly associated with potentially-fatal complications. Micronutrient imbalance is associated with many cardiovascular diseases, such as arrythmias, heart failure, and ischemic heart disease. It has been also observed in coronavirus disease 2019 (COVID-19), particularly in most severe patients. The relationship between cardiovascular diseases and COVID-19 is mutual: the latter triggers cardiovascular disease onset and worsening while patients with previous cardiovascular disease may develop a more severe form of COVID-19. In addition to the well-known pathophysiological mechanisms binding COVID-19 and cardiovascular diseases together, increasing importance is being given to the impact of micronutrient alterations, often present during COVID-19 and able to affect the balance responsible for a good functioning of the cardiovascular system. In particular, hypokalemia, hypomagnesemia, hyponatremia, and hypocalcemia are strongly associated with worse outcome, while vitamin A and D deficiency are associated with thromboembolic events in COVID-19. Thus, considering how frequent the cardiovascular involvement is in patients with COVID-19, and how it majorly affects their prognosis, this manuscript provides a comprehensive review on the role of micronutrient imbalance in the interconnection between COVID-19 and cardiovascular diseases.

MTHFR Polymorphism and Folic Acid Supplementation Influence Serum Homocysteine Levels in Psoriatic Patients Treated with Methotrexate

Background: Hyperhomocysteinemia has been reported in psoriasis. We investigated the effect of methylenetetrahydrofolate reductase (MTHFR), polymorphism and folic acid supplementation on serum homocysteine levels in psoriasis. Methods: Serum homocysteine levels were detected at baseline and at week 12 in 201 patients who were genotyped with MTHFR rs1801133 without and 93 psoriatic patients with folate supplement. Results: TT genotype carriers of MTHFR rs1801133 had significantly higher serum homocysteine levels at baseline and at week 12, a better PASI 75 response rate at week 8, and a higher PASI 90 response rate at week 12 than the CT and CC genotype carriers. Multiple regression analysis demonstrated that serum homocysteine concentration at baseline was significantly associated with sex, weight, PASI score at baseline, and the rs1801133 genotype. The significant upregulation of serum homocysteine levels after treatment with methotrexate (MTX) was only observed in male CT and CC genotype carriers and female CC genotype carriers. In contrast, folic acid supplementation significantly decreased serum homocysteine levels after MTX treatment but only in male psoriatic patients. Conclusions: The effect of MTX on serum homocysteine levels was associated with the polymorphism of MTHFR rs1801133 and sex. Folic acid supplementation only decreased serum homocysteine levels in male psoriatic patients.

Association between hyperhomocysteinaemia and the risk of all-cause and cause-specific mortality among adults in the USA

Hyperhomocysteinaemia (HHcy) is associated with all-cause mortality in some disease states. However, the correlation between HHcy and the risk of mortality in the general population has rarely been researched. We aimed to evaluate the association between HHcy and all-cause and cause-specific mortality among adults in the USA. This study analysed data from the National Health and Nutrition Examination Survey database (1999-2002 survey cycle). A multivariable Cox regression model was built to evaluate the correlation between HHcy and all-cause and cause-specific mortality. Smooth curve fitting was used to analyse their dose-dependent relationship. A total of 8442 adults aged 18-70 years were included in this study. After a median follow-up period of 14·7 years, 1007 (11·9 %) deaths occurred including 197 CVD-related deaths, 255 cancer-related deaths and fifty-eight respiratory disease deaths. The participants with HHcy had a 93 % increased risk of all-cause mortality (hazard ratio (HR) 1·93; 95 % CI (1·48, 2·51)), 160 % increased risk of CVD mortality (HR 2·60; 95 % CI (1·52, 4·45)) and 82 % increased risk of cancer mortality (HR 1·82; 95 % CI (1·03, 3·21)) compared with those without HHcy. For unmeasured confounding, E-value analysis proved to be robust. In conclusion, HHcy was associated with high risk of all-cause and cause-specific (CVD, cancer) mortality among adults aged below 70 years.

Hyperhomocysteinemia and Ischemic Stroke: A Potential Dose-Response Association-A Systematic Review and Meta-analysis

Background and Purpose  Previous studies suggest an association between increased homocysteine (Hcy) and risk of ischemic stroke. Yet, it remains unknown whether a dose-response association exists between Hcy levels and risk of ischemic stroke. Methods  Systematic literature searches were performed in PubMed, Embase, Scopus, and Web of Science. Inclusion criteria were studies investigating ischemic stroke risk in an adult population with measured Hcy levels. We computed odds ratios (ORs) for a 5 µmol/L increase in Hcy levels using a random effects meta-analysis. Results  In total, 108 studies met the inclusion criteria of which 22 were rated as high-quality studies, and 20 studies included a dose-response analysis. Hcy levels were analyzed either as a continuous or categorical variable. The majority of the studies found an increased risk of ischemic stroke when comparing the highest-to-lowest Hcy strata. A graded association was observed over the Hcy strata, indicating a dose-response association, with the most apparent effect when Hcy levels exceeded approximately 15 µmol/L. No studies explored a potential nonlinear association between Hcy levels and ischemic stroke. Six studies were included in a meta-analysis, showing an OR of 1.43 (95% confidence interval [CI]: 1.28-1.61) per 5 µmol/L increase in Hcy levels. Conclusion  This review and meta-analysis indicate a dose-response association between Hcy levels and ischemic stroke. An evident increase in effect measures was observed when Hcy levels exceeded 15 µmol/L, indicating a nonlinear association between ischemic stroke and Hcy levels. This nonlinear association warrants further study. This study is registered with clinical trial ( https://www.crd.york.ac.uk/prospero/ ; unique identifier: CRD42019130371).

Involvements of Hyperhomocysteinemia in Neurological Disorders

Homocysteine (HCY), a physiological amino acid formed when proteins break down, leads to a pathological condition called hyperhomocysteinemia (HHCY), when it is over a definite limit. It is well known that an increase in HCY levels in blood, can contribute to arterial damage and several cardiovascular disease, but the knowledge about the relationship between HCY and brain disorders is very poor. Recent studies demonstrated that an alteration in HCY metabolism or a deficiency in folate or vitamin B12 can cause altered methylation and/or redox potentials, that leads to a modification on calcium influx in cells, or into an accumulation in amyloid and/or tau protein involving a cascade of events that culminate in apoptosis, and, in the worst conditions, neuronal death. The present review will thus summarize how much is known about the possible role of HHCY in neurodegenerative disease.

The Antioxidant Role of One-Carbon Metabolism on Stroke

One-carbon (1C) metabolism is a metabolic network that is centered on folate, a B vitamin; it integrates nutritional signals with biosynthesis, redox homeostasis, and epigenetics. This metabolic pathway also reduces levels of homocysteine, a non-protein amino acid. High levels of homocysteine are linked to increased risk of hypoxic events, such as stroke. Several preclinical studies have suggested that 1C metabolism can impact stroke outcome, but the clinical data are unclear. The objective of this paper was to review preclinical and clinical research to determine whether 1C metabolism has an antioxidant role on stroke. To accomplish the objective, we searched for publications using the following medical subject headings (MeSH) keywords: antioxidants, hypoxia, stroke, homocysteine, one-carbon metabolism, folate, methionine, and dietary supplementation of one-carbon metabolism. Both pre-clinical and clinical studies were retrieved and reviewed. Our review of the literature suggests that deficiencies in 1C play an important role in the onset and outcome of stroke. Dietary supplementation of 1C provides beneficial effects on stroke outcome. For stroke-affected patients or individuals at high risk for stroke, the data suggest that nutritional modifications in addition to other therapies could be incorporated into a treatment plan.

Plasma Homocysteine and Cardiovascular Organ Damage in a Population with a High Prevalence of Risk Factors

PURPOSE

It is unclear whether plasma homocysteine (Hcy) has a direct noxious impact on the cardiovascular (CV) system or whether its association with cardiovascular events (CVEs) is mediated by established risk factors. To explore the role of Hcy in CV impairment, the study evaluated cross-sectional relationships between plasma Hcy and indices of CV organ damage together with the associations of these indices with the history of CVEs.

METHODS

In 269 patients with a high prevalence of diabetes, dyslipidemia, and hypertension, the carotid intima-media thickness, ankle-brachial index (ABI), reactive hyperemic index, carotid-femoral pulse wave velocity (cfPWV), left ventricular (LV) mass, and cardiac index were measured.

RESULTS

132 patients had carotid plaque, 31 ABI < 0.90, 126 endothelial dysfunction, 66 increased cfPWV, 125 LV hypertrophy (LVH), 153 decreased cardiac index, and 115 a history of CVEs. Plasma Hcy levels were related to LV mass and ABI, after adjustment for covariates and creatinine. Significantly higher Hcy levels were found in patients with LVH (8.5 [4.4] vs 7.6 [2.8] μmol/L; adjusted P = .001) and ABI < 0.9 (10.4 [3.8] vs 7.9 [3.4] μmol/L; adjusted P = .001) than in those with LV mass and ABI within limits. Hcy levels were comparable between patients with and without carotid plaques, increased arterial stiffness, impaired endothelial, and LV pump function. Within markers of CV organ damage, only LVH was associated with a history of CVEs.

CONCLUSION

This study demonstrated an independent association between Hcy and LV mass as well as between LVH and a history of CVEs and suggests that LVH may represent 1 of the pathophysiologic links between Hcy and CV risk.

Novel method for l-methionine determination using l-methionine decarboxylase and application of the enzyme for l-homocysteine determination

Abbreviations

DTT: dithiothreitol; IPTG: isopropyl-β-d-thiogalactopyranoside; KPB: potassium phosphate buffer; MBTH: 3-methyl-2-benzothiazolinonehydrazone; mdc: the gene coding l-methionine decarboxylase; MetDC: l-methionine decarboxylase; mgl: the gene coding l-methionine γ-lyase; MGL: l-methionine γ-lyase; PLP: pyridoxal 5ʹ-phosphate

Single nucleotide polymorphism of MTHFR rs1801133 associated with elevated Hcy levels affects susceptibility to cerebral small vessel disease

Background

Methylenetetrahydrofolate reductase (MTHFR) is indispensable for the conversion of homocysteine (Hcy) to methionine. The single nucleotide polymorphism (SNP) of MTHFR gene (rs1801133, C667T) is correlated with decreased enzyme activity that eventually results in elevated plasma Hcy levels. Hyperhomocysteinemia has been confirmed to be involved in the pathogenesis of stroke, cerebral small vessel disease (CSVD), various metabolic disorders and so on. However, the relationship between the MTHFR gene polymorphisms, Hcy, and CSVD has not been investigated. In this study, the relationship between SNPs of MTHFR gene and CSVD was determined after adjusting for cardiovascular risk factors, and the potential mechanism based on Hcy levels was explored.

Methods

A total of 163 consecutive CSVD patients were collected as the case group. In the corresponding period, 326 healthy people were selected as the control group, who were matched to these cases according to age (±2 years) and gender at a ratio of 2:1. SNPs of MTHFR rs1801133, rs1801131, rs2274976, rs4846048, rs4846049, rs13306561 and rs3737964, were genotyped with TaqMan Pre-Designed SNP Genotyping Assays. Plasma Hcy levels were detected using Hcy reagent through enzymatic cycling assay. Multivariate analysis was used to identify the SNPs associated with CSVD susceptibility. Plasma Hcy levels were compared between different genotypes.

Results

The MTHFR rs1801133 TT and CT genotype had increased risk for CSVD, and the OR was higher in the TT genotype than in the CT genotype (2.307 vs 1.473). The plasma Hcy levels of different genotypes showed the tendency of the TT genotype > CT genotype > CC genotype (19.91 ± 8.73 pg/ml vs 17.04 ± 5.68 pg/ml vs 14.96 ± 4.85 pg/ml).

Conclusions

The SNP of MTHFR rs1801133 was correlated with CSVD, and the TT and CT genotypes had increased risk for CSVD compared to the CC genotype. The potential mechanism was associated with elevated Hcy levels.

Hyperhomocysteinemia Causes Severe Intraoperative Thrombotic Tendency in Superficial Temporal Artery-middle Cerebral Artery Bypass

CASE

Two years ago, annual magnetic resonance imaging for unruptured right internal carotid artery aneurysm of a 47-year-old woman detected a cerebral infarct in her right occipital lobe which was unknown etiology and antiplatelet therapy was initiated. She presented with sensory disorder of her left fingers 4 months ago. Infarction in right parieto-occipital cortex and severe stenosis of right middle cerebral artery was revealed. Her laboratory test was normal except remarkably high homocysteine value. Regardless of dual anti-platelet therapy, she suffered from repeated minor stroke and the stenosis was progressing. Therefore, right superficial temporal artery - middle cerebral artery bypass was undertaken. Aspirin and clopidogrel were withdrawn 1 week before the surgery. Two branches were anastomosed with 2 separate frontal M4 branches. Although patency was confirmed immediately after the anastomosis, thrombus formation was revealed after 10 minutes. We needed to perform removal of the thrombus and re-anastomosis twice. Intraoperative administration of aspirin and ozagrel alleviated thrombotic tendency. After surgery, antiplatelet therapy and supplementation with folate and vitamin B were performed. Her postoperative course was uneventful and patency of both anastomoses was confirmed.

DISCUSSION

Controversy still exists regarding preoperative antiplatelet therapy before superficial temporal artery-middle cerebral artery bypass, and folates and B6-12 vitamins supplementation for hyperhomocysteinemia. Considering intraoperative thrombo tendency in our case, it is recommended to evaluate the homocysteine level before bypass surgery for intracranial stenosis especially for young patients or patients with unknown etiology. Before bypass surgery of the patient with hyperhomocysteinemia, continuation of perioperative antiplatelet drugs and supplementation with folates and B6-12 vitamins are mandatory.

Association between methylene tetrahydrofolate reductase polymorphisms and risk of ischemic stroke

Background: The methylene tetrahydrofolate reductase (MTHFR) is a folate-dependent enzyme which catalyzes the conversion of homocysteine to methionine. Two single nucleotide polymorphisms (SNPs) within this gene namely rs1801133 (C677T) and rs1801131 (A1298C) have been associated with elevated risk of ischemic stroke and total serum homocysteine in some populations.Aim: To assess associations between MTHFR SNPs and risk of ischemic stroke in Iranian population.Methods: In the current case-control study, we genotyped rs1801133 and rs1801131 SNPs in 318 Iranian patients with history of ischemic stroke and 400 age- and sex-matched controls using tetra-primer amplification refractory mutation system-polymerase chain reaction method.Results: The rs1801133 was significantly associated with risk of stroke in recessive model (OR (95% CI) = 1.89 (1.12-3.20), p = 0.03). The CT haplotype (rs1801131 and rs1801133, respectively) was significantly over-represented in patients compared with controls (OR (95% CI) = 1.71 (0.25-2.32), p = 0.002).Conclusion: Consequently, our data demonstrate contribution of MTHFR variants in risk of ischemic stroke in Iranian population.

Astaxanthin Protects PC12 Cells against Homocysteine- and Glutamate-Induced Neurotoxicity

Memory impairment has been shown to be associated with glutamate (Glu) excitotoxicity, homocysteine (Hcy) accumulation, and oxidative stress. We hypothesize that Glu and Hcy could damage neuronal cells, while astaxanthin (ATX) could be beneficial to alleviate the adverse effects. Using PC12 cell model, we showed that Glu and Hcy provoked a huge amount of reactive oxygen species (ROS) production, causing mitochondrial damage at EC₅₀ 20 and 10 mm, respectively. The mechanisms of action include: (1) increasing calcium influx; (2) producing ROS; (3) initiating lipid peroxidation; (4) causing imbalance of the Bcl-2/Bax homeostasis; and (5) activating cascade of caspases involving caspases 12 and 3. Conclusively, the damages caused by Glu and Hcy to PC12 cells can be alleviated by the potent antioxidant ATX.

The association of MTHFR C677T variant with increased risk of ischemic stroke in the elderly population: a meta-analysis of observational studies

Background

C677T point mutation in methylenetetrahydrofolate reductase (MTHFR) gene have been found to be associated with ischemic stroke in general population, while the results seem inconsistent. We aim to assess the association between variant MTHFR C677T variant and increased risk of ischemic stroke and focus on the elderly population.

Methods

We searched PubMed, Embase, Cochrane Library, and Web of Science for eligible studies. Odds ratios (ORs) were calculated with the two-tailed 95% confidence intervals (CIs) by using a random effects model to evaluate any possible association. Among the Chinese and non-Chinese populations, we conducted a subgroup analysis.

Results

The electronic database search yielded 1,358 citations as of December 2017; finally, nine case-control studies involving 3,337 subjects fulfilled our eligibility criteria for inclusion in the study. The pooled results showed that MTHFR C677T variant increased the risk of ischemic stroke (OR = 1.23, 95%CI 1.06–1.43, P = 0.0067 for CT + TT vs. CC; OR = 1.18, 95%CI 1.01–1.38, P = 0.0333 for CT vs. CC; OR = 1.41, 95%CI 1.14–1.75, P = 0.0016 for TT vs. CC; OR = 1.27, 95%CI 1.05–1.54, P = 0.0145 for TT vs. CC + CT; OR = 1.18, 95%CI 1.06–1.31, P = 0.0023 for T-allele vs. C-allele). Further subgroup analyses in the Chinese population indicated that MTHFR C677T variant was associated with a higher risk of ischemic stroke.

Conclusion

Our findings showed that T-allele increases risk for stroke in the pooled sample. This association was statistically significant in the Chinese cohorts and showed a similar trend in the non-Chinese cohorts. (Word count: 237).

Cardiovascular disease in transgendered people: A review of the literature and discussion of risk

This review examines the impact of gender affirming hormone therapy used in the transgendered and non-binary populations on cardiovascular outcomes and surrogate markers of cardiovascular health. Current evidence suggests that hormonal therapy for transgendered women decreases or is neutral regarding myocardial infarction risk. There is an increased incidence of venous thromboembolism (VTE), but newer studies suggest that the risk is significantly lower than previously described. For transgendered men, there appears to be an adverse effect on lipid parameters but this does not translate into an increased risk of cardiovascular disease above that of general male population. In all transgendered people, risk factor interventions such as smoking cessation, weight management and treatment of co-morbid conditions are important in optimising cardiovascular health. The effect of gender affirming hormonal therapy in transgendered people is difficult to interpret due to the variety of hormone regimens used, the relative brevity of the periods of observation and the influence of confounding factors such as the historical use of less physiological, oestrogens such as conjugated equine oestrogen and ethinylestradiol which are more pro-thrombotic than the 17β oestradiol that is used in modern practice.

Frequency of Homocysteinemia in Young Ischemic Stroke Patients and Its Relationship with the Early Outcome of a Stroke

Objective To find out the frequency of hyperhomocysteinemia in young ischaemic stroke patients and its relationship with early morbidity and mortality. Methods This prospective study was conducted on young ischemic stroke patients in Pakistan Atomic Energy Commission General Hospital, Islamabad. Ischaemic stroke patients of age < 45 years were selected from both the outpatient and inpatient departments. A fasting venous blood sample was sent for analysis. Data was collected through a structured proforma and were analyzed using SPSS 24.0 (IBM Corp, Armonk, NY, US). The outcome was measured at discharge using the modified Rankin scale. Results The mean age of the 71 patients in the study was 35.8 years. Overall, 36 (50.7%) cases had hyper-homocysteinemia. The frequency was significantly higher in males and in the age group 36-45 years (63.4%). Levels of homocysteine did not significantly affect the outcome at discharge. Conclusion Hyperhomocysteinaemia, a modifiable risk factor for ischaemic stroke, was seen in about half of young stroke patients. The levels of homocysteine did not correlate with early stroke outcome.

Changes in one-carbon metabolism and DNA methylation in the hearts of mice exposed to space environment-relevant doses of oxygen ions (16O)

Cardiovascular disease constitutes an important threat to humans after space missions beyond the Earth's magnetosphere. Epigenetic alterations have an important role in the etiology and pathogenesis of cardiovascular disease. Previous research in animal models has shown that protons and ⁵⁶Fe ions cause long-term changes in DNA methylation and expression of repetitive elements in the heart. However, astronauts will be exposed to a variety of ions, including the smaller fragmented products of heavy ions after they interact with the walls of the space craft. Here, we investigated the effects of ¹⁶O on the cardiac methylome and one-carbon metabolism in male C57BL/6 J mice. Left ventricles were examined 14 and 90 days after exposure to space-relevant doses of 0.1, 0.25, or 1 Gy of ¹⁶O (600 MeV/n). At 14 days, the two higher radiation doses elicited global DNA hypomethylation in the 5'-UTR of Long Interspersed Nuclear Elements 1 (LINE-1) compared to unirradiated, sham-treated mice, whereas specific LINE-1 elements exhibited hypermethylation at day 90. The pericentromeric major satellites were affected both at the DNA methylation and expression levels at the lowest radiation dose. DNA methylation was elevated, particularly after 90 days, while expression showed first a decrease followed by an increase in transcript abundance. Metabolomics analysis revealed that metabolites involved in homocysteine remethylation, central to DNA methylation, were unaffected by radiation, but the transsulfuration pathway was impacted after 90 days, with a large increase in cystathione levels at the lowest dose. In summary, we observed dynamic changes in the cardiac epigenome and metabolome three months after exposure to a single low dose of oxygen ions.

GluN2A-NMDA receptor-mediated sustained Ca2+ influx leads to homocysteine-induced neuronal cell death

Homocysteine, a metabolite of the methionine cycle, is a known agonist of N-methyl-d-aspartate receptor (NMDAR), a glutamate receptor subtype and is involved in NMDAR-mediated neurotoxicity. Our previous findings have shown that homocysteine-induced, NMDAR-mediated neurotoxicity is facilitated by a sustained increase in phosphorylation and activation of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK MAPK). In the current study, we investigated the role GluN1/GluN2A-containing functional NMDAR (GluN2A-NMDAR) and GluN1/GluN2B-containing functional NMDAR (GluN2B-NMDAR) in homocysteine-induced neurotoxicity. Our findings revealed that exposing primary cortical neuronal cultures to homocysteine leads to a sustained low-level increase in intracellular Ca²⁺ We also showed that pharmacological inhibition of GluN2A-NMDAR or genetic deletion of the GluN2A subunit attenuates homocysteine-induced increase in intracellular Ca²⁺ Our results further established the role of GluN2A-NMDAR in homocysteine-mediated sustained ERK MAPK phosphorylation and neuronal cell death. Of note, the preferential role of GluN2A-NMDAR in homocysteine-induced neurotoxicity was distinctly different from glutamate-NMDAR-induced excitotoxic cell death that involves overactivation of GluN2B-NMDAR and is independent of ERK MAPK activation. These findings indicate a critical role of GluN2A-NMDAR-mediated signaling in homocysteine-induced neurotoxicity.

Hydrolysis of homocysteine thiolactone results in the formation of Protein-Cys-S-S-homocysteinylation

An increased level of homocysteine, a reactive thiol amino acid, is associated with several complex disorders and is an independent risk factor for cardiovascular disease. A majority (>80%) of circulating homocysteine is protein bound. Homocysteine exclusively binds to protein cysteine residues via thiol disulfide exchange reaction, the mechanism of which has been reported. In contrast, homocysteine thiolactone, the cyclic thioester of homocysteine, is believed to exclusively bind to the primary amine group of lysine residue leading to N-homocysteinylation of proteins and hence studies on binding of homocysteine thiolactone to proteins thus far have only focused on N-homocysteinylation. Although it is known that homocysteine thiolactone can hydrolyze to homocysteine at physiological pH, surprisingly the extent of S-homocysteinylation during the exposure of homocysteine thiolactone with proteins has never been looked into. In this study, we clearly show that the hydrolysis of homocysteine thiolactone is pH dependent, and at physiological pH, 1 mM homocysteine thiolactone is hydrolysed to ~0.71 mM homocysteine within 24 h. Using albumin, we also show that incubation of HTL with albumin leads to a greater proportion of S-homocysteinylation (0.41 mol/mol of albumin) than N-homocysteinylation (0.14 mol/mol of albumin). S-homocysteinylation at Cys³⁴ of HSA on treatment with homocysteine thiolactone was confirmed using LC-MS. Further, contrary to earlier reports, our results indicate that there is no cross talk between the cysteine attached to Cys³⁴ of albumin and homocysteine attached to lysine residues.

Long-term exposures to Hypersaline particles associated with increased levels of Homocysteine and white blood cells: A case study among the village inhabitants around the semi-dried Lake Urmia

The dried bed of the world's second largest permanent Hypersaline lake, Lake Urmia, acts as a Hypersaline particle emission source. In the present study we aim to assess the health impact of this disaster and examine the association of Hypersaline particles with total and differential white blood cell counts (WBC) and homocysteine (Hcy), the biomarkers of cardiovascular diseases, in the residents around Lake Urmia. Based on the previous study three regions were selected as clean and polluted regions for ambient particulate matter (APM) from 2008 to 2015. Concentration of APM (PM₁₀, PM_2.5 and PM₁; particulate matter with aerodynamic diameter of less than 10, 2.5 and 1 µm, respectively) was measured in the selected regions and totally, 123 participants were selected randomly from villagers who have lived in the selected regions for at least eight years. Biomarkers and covariates were measured in the selected regions and were analyzed using multiple linear regression models. We found a statistically significant association between APM and selected biomarkers (Hcy, total WBC, neutrophil, monocyte, lymphocyte and basophile) in the polluted regions. These results are consistent with our hypothesis that long-term exposure to Hypersaline particles originated from drying Urmia Hypersaline Lake is related to increased cardiovascular risk biomarkers.

High-throughput blood sample preparation for single nucleotide polymorphism genotyping in less than 25 min

Straightforward, rapid and high-throughput pretreatment for single nucleotide polymorphisms (SNP) genotyping is critically needed in clinical practice. However, all existing SNP genotyping methods require DNA purification step, which is labor-intensive and time-consuming. We develop a protocol for SNP genotyping by combining whole blood lysis (WBL) with qPCR and justify the practicality of our method in blood samples from 140 donors, including 40 samples from healthy donors, and 100 samples from donors with either low white blood cell counts, high level of serum uric acid or triglyceride. When compared with Sanger sequencing, the gold standard for SNP genotyping, our method exhibits a 100% consistency in the aspect of sensitivity and specificity. In addition, our method can obtain amplifiable DNA within 25 mins (which is the fastest to the best of our knowledge) from 48 samples. The blood samples, even with low white blood cell counts, high level of serum uric acid or triglyceride could not affect the sensitivity and specificity of our method. Our study demonstrates that the combination of WBL and qPCR genotyping can serve as a high-throughput and robust approach for routine clinical SNP genotyping.

Plasma homocysteine levels and intracranial plaque characteristics: association and clinical relevance in ischemic stroke

Background

Elevated plasma homocysteine (Hcy) is an independent risk factor for ischemic stroke. This study aimed to evaluate the association between Hcy levels and intracranial plaque characteristics and to investigate their clinical relevance in ischemic stroke.

Methods

Ninety-four patients with intracranial atherosclerosis (ICAS) were enrolled. Plasma Hcy levels were measured. Intracranial plaque characteristics including plaque enhancement, stenosis ratio, T2 and T1 hyperintense components were assessed on high-resolution magnetic resonance imaging. Logistic regression model was constructed to analyze the association between high Hcy levels and plaque characteristics, and their synergistic effects to predict the likelihood for ischemic stroke, while adjusting for demographics and traditional atherosclerotic risk factors.

Results

Elevated Hcy level was associated with strong plaque enhancement independently of age, sex, serum creatinine levels and other atherosclerotic risk factors ((P < 0.001, OR 6.00, 95% confidence interval [CI] 2.28–15.74). Both strong plaque enhancement (P = 0.026, OR 5.63, 95% CI 1.23–25.81) and high Hcy level (P = 0.018, OR 6.20, 95% CI 1.36–28.26) were correlated with acute ischemic stroke. The combination of them strengthened the ability to stratify the likelihood for ischemic stroke, with an improved area under the receiver operating characteristic curve (AUC) of 0.871, significantly higher than that of strong plaque enhancement (0.755) and high Hcy level (0.715) alone (P < 0.05 for both).

Conclusions

High Hcy level appears to have association with intracranial strong plaque enhancement. The combined assessment of plasma Hcy levels and plaque enhancement may improve ischemic stroke risk stratification.

Gaussian numerical analysis and terahertz spectroscopic measurement of homocysteine

Homocysteine is an amino acid related to metabolism in human vivo, which is closely related to cardiovascular disease, senile dementia, bone fracture, et al. Currently, the usual medical test methods for homocysteine include high performance liquid chromatography (HPLC), fluorescence polarization immunoassay (FPIA) and enzyme-linked immunosorbent assay (ELISA), which are time-consuming or expensive. In this paper, we first analyze the vibration and rotation of homocysteine molecules by using density functional theory, and then we ensure that the theoretical absorption peaks are located in the range of the terahertz spectrum. Then, based on the terahertz time-domain spectroscopy system, we measured the absorption spectrum of homocysteine under different concentrations. It is found that as the detection of the concentration, the terahertz results present higher accuracy than that of the laser Raman spectrum, which can be used as the reference for the evaluation of pathological stage. These results are of great significance for the exact and quick diagnosis of homocysteine-related diseases in clinical medicine.

Homocysteine and homocysteine-related compounds: an overview of the roles in the pathology of the cardiovascular and nervous systems

Homocysteine, an amino acid containing a sulfhydryl group, is an intermediate product during metabolism of the amino acids methionine and cysteine. Hyperhomocysteinemia is used as a predictive risk factor for cardiovascular disorders, the stroke progression, screening for inborn errors of methionine metabolism, and as a supplementary test for vitamin B₁₂ deficiency. Two organic systems in which homocysteine has the most harmful effects are the cardiovascular and nervous system. The adverse effects of homocysteine are achieved by the action of several different mechanisms, such as overactivation of N-methyl-d-aspartate receptors, activation of Toll-like receptor 4, disturbance in Ca²⁺ handling, increased activity of nicotinamide adenine dinucleotide phosphate-oxidase and subsequent increase of production of reactive oxygen species, increased activity of nitric oxide synthase and nitric oxide synthase uncoupling and consequent impairment in nitric oxide and reactive oxygen species synthesis. Increased production of reactive species during hyperhomocysteinemia is related with increased expression of several proinflammatory cytokines, including IL-1β, IL-6, TNF-α, MCP-1, and intracellular adhesion molecule-1. All these mechanisms contribute to the emergence of diseases like atherosclerosis and related complications such as myocardial infarction, stroke, aortic aneurysm, as well as Alzheimer disease and epilepsy. This review provides evidence that supports the causal role for hyperhomocysteinemia in the development of cardiovascular disease and nervous system disorders.

Metabolomics analysis reveals an effect of homocysteine on arachidonic acid and linoleic acid metabolism pathway

An increase in serum homocysteine level has been associated with an increased risk of vascular disease; however, the biochemical mechanisms that underlie these effects remain largely unknown. The present study aimed to use high-performance liquid chromatography-mass spectrometry (HPLC‑MS) to demonstrate the effects of serum homocysteine on human blood metabolites. A total of 75 fasting serum samples were investigated in the present study. Using a threshold of 15 µmol/l serum homocysteine level, samples were divided into high‑ and low‑homocysteine groups, and the serum extracts were analyzed with an HPLC‑MS‑based method. A total of 269 features exhibited significant differences and correlation with serum homocysteine levels in the electrospray ionization‑positive [ESI(+)] mode, and 69 features were identified in the ESI(‑) mode between the two groups. The principal component analysis plot revealed a separation between the high‑ and the low‑homocysteine groups. Metabolite set enrichment analysis identified arachidonic acid metabolism and linoleic acid metabolism as the two pathways with significantly enriched differences. These results revealed that arachidonic acid and linoleic acid metabolism may be associated with serum homocysteine levels and may be involved in homocysteine-induced vascular disease.

Homocysteine Levels in Plasma and Sensorineural Hearing Loss in Patients with Pseudoexfoliation Syndrome

PURPOSE

To determine the incidence and severity of hearing loss in different frequencies in patients with pseudoexfoliation. Furthermore, possible links between homocysteine and pseudoexfoliation were evaluated.

METHODS

Seventy-five consecutive patients with pseudoexfoliation and 75 sex- and age-matched subjects without pseudoexfoliation as control group were included in this prospective case-control study. Pure-tone audiometry was obtained in all subjects in both groups. Blood samples were obtained from 70 patients with pseudoexfoliation after overnight fasting for levels of homocysteine and analyzed by routine laboratory measurements.

RESULTS

Fifty-two (69%) patients with pseudoexfoliation and 39 (52%) controls had sensorineural hearing loss in speech frequencies. The difference between pseudoexfoliation and control group with regard to the frequency of sensorineural hearing loss in speech frequencies was statistically significant (p=0.03). No relationship was found between the degree of glaucomatous damage and hearing threshold variables in the patients with pseudoexfoliation glaucoma. Plasma homocysteine levels showed no significant difference when patients with pseudoexfoliation and hearing loss were compared with patients with pseudoexfoliation and normal hearing threshold (p=0.5). Hyperhomocysteinemia was found in 58% (29/50) of pseudoexfoliation patients with hearing loss, and 55 % (11/20) of pseudoexfoliation patients with normal hearing threshold (p=0.8). No statistically significant correlation was found between plasma homocysteine and hearing loss in patients with pseudoexfoliation.

CONCLUSIONS

These findings suggest an association between sensorineural hearing loss and pseudoexfoliation in patients with pseudoexfoliation and glaucoma. The severity of hearing loss was not correlated with the degree of glaucomatous damage. There is no association between increased homocysteine levels and hearing loss in patients with pseudoexfoliation.

A label-free fluorimetric detection of biothiols based on the oxidase-like activity of Ag+ ions

In this work, a label-free and sensitive fluorimetric method has been developed for the detections of biothiols including cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), based on the specific biothiol-induced inhibition of the oxidase-like activity of silver ions (Ag⁺). It is well established that o-phenylenediamine (OPD) can be oxidized by Ag⁺ ions to generate fluorescent 2,3-diaminophenazine (OPDox). The introduction of biothiols would inhibit the oxidation of OPD by Ag⁺ due to the strong coordination between biothiols and Ag⁺. The changes of fluorescence intensities obtained in the Ag⁺-OPD system exhibited good linear correlations in the ranges of 0.50-30.0μM for Cys, 1.0-45.0μM for Hcy and 0.50-40.0μM for GSH. The detection limits (S/N=3) of Cys, Hcy and GSH were 110nM, 200nM and 150nM, respectively. Subsequently, the developed fluorimetric method was successfully applied for the detection of biothiols in human serum.

Ocular Pseudoexfoliation Syndrome Linkage to Cardiovascular Disease

PURPOSE OF REVIEW

Pseudoexfoliation syndrome (PEX) is a common cause of open-angle glaucoma that is characterized by stress-induced elastic microfibrillopathy related to an accumulation of matrix metalloproteinases. The accumulation of matrix metalloproteinases increases deposition of protein substance within ocular structures and other organs including the heart. Many studies have associated the presence of cardiovascular disease with pseudoexfoliation syndrome, but much debate exists between studies in terms of significant relationships. The following meta-analysis aims to relate pseudoexfoliation syndrome with certain cardiovascular events and disorders. A thorough literature review was performed to acquire information concerning PEX patients with certain cardiovascular disorders. Diseases considered included myocardial infarction, ischemic heart disease, angina, congestive heart failure, cardiomyopathy, aortic aneurysm, hypertension, and homocystinuria. Patients without evidence of pseudoexfoliation disease were the controls of our study. Multiple forest plots were created to compile and analyze collected data for statistical comparison.

RECENT FINDINGS

From a literature review, 18 studies were selected for our analysis. Cardiovascular disorders that had a statistically significant association (within a 95 % confidence interval) with PEX included ischemic heart disease, aortic aneurysms, and homocystinuria. The association between ischemic heart disease and PEX was statistically significant (p = 0.045). Myocardial infarction, chronic ischemic heart disease, angina, and hypertension did not show a correlation of relationship with the presence of pseudoexfoliation. Patients with PEX are prone to present with ischemic heart disease in addition to abdominal aortic aneurysms and homocystinuria. Patients that present with PEX should be screened for these detrimental cardiovascular disorders.

Homocysteine metabolism is associated with cerebrospinal fluid levels of soluble amyloid precursor protein and amyloid beta

Disturbed homocysteine metabolism may contribute to amyloidogenesis by modulating the amyloid precursor protein (APP) production and processing. The objective of this study was to investigate the relationships between cerebral amyloid production and both blood and cerebrospinal fluid (CSF) markers of the homocysteine metabolism. We assessed CSF concentrations of soluble APPα, soluble APPβ, and amyloid β1-42 (Aβ1-42), as well as plasma levels of homocysteine (Hcys), total vitamin B12, and folate, and CSF concentrations of homocysteine (Hcys-CSF), 5-methyltetrahydrofolate (5-MTHF), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) in 59 subjects with normal cognition. Linear regression analyses were performed to assess associations between homocysteine metabolism parameters and amyloid production. The study was approved by the Ethical Committee of the University of Bonn. After controlling for age, gender, APOEe4 status, and albumin ratio (Qalb), higher Aβ1-42 CSF levels were associated with high Hcys and low vitamin B12 plasma levels as well as with high Hcys, high SAH, and low 5-MTHF CSF levels. Higher CSF concentrations of sAPPα and sAPPβ were associated with high SAH levels. The results suggest that disturbed homocysteine metabolism is related to increased CSF levels of sAPP forms and Aβ1-42, and may contribute to the accumulation of amyloid pathology in the brain. Disturbed homocysteine metabolism may contribute to amyloidogenesis by modulating the amyloid precursor protein (APP) production and processing. We found associations between CSF levels of soluble APP forms and Aβ1-42, and markers of the homocysteine metabolism in both plasma and CSF in adults with normal cognition. Disturbed homocysteine metabolism may represent a target for preventive and early disease-modifying interventions in Alzheimer's disease.

Homocysteine Level and Coronary Artery Disease

Atherosclerosis, and its most common manifestation, coronary artery disease (CAD), are rather common causes of morbidity and mortality worldwide. Recognition of its various risk factors is important to planning effective preventive measures. After the homocysteine theory was presented in 1969, attention has been directed toward the serum homocysteine level as a coronary artery disease risk factor. The authors aimed to assess the relationship between hyperhomocysteinemia and CAD in an Iranian population. In a case control study, 197 individuals (male: 123 [62.4%]) who were scheduled for coronary angiography were selected. Venous samples were taken from the patients in fasting state before angiography. Data about age, sex, risk factors (eg, hypertension, diabetes, smoking, hyperlipidemia, obesity) were obtained from prepared questionnaires. Homocysteine levels in patients were measured by ELISA method. A homocysteine level above 15 µmol/liter was considered high. Angiography reports and homocysteine levels were analyzed by independent sample t test, one-way ANOVA, multiple linear regression, and stratified analysis. In comparison with the patients with normal angiography reports (32.5%), patients with abnormal angiography reports (67.5%) had increased levels of homocysteine (p=0.001). About 28.1% of patients with normal angiography reports had hyperhomocysteinemia. After further evaluation, linear correlations were detected between the numbers of involved vessels and homocysteine level (p=0.000). Multiple linear regression analysis of data detected that in individuals without any risk factors, the relationship was stronger and more meaningful (p=0.000). These data show that hyperhomocysteinemia is related to CAD as an independent risk factor. In individuals without any risk factors a linear correlation between homocysteine level and numbers of coronary artery involvement was present. If this equation is confirmed prospectively in other studies, the level of plasma homocysteine may he used as a noninvasive way of predicting the number of diseased coronary arteries.

Design and statistical issues in the homocysteinemia in kidney and end stage renal disease (HOST) study

The Homocysteine Study (HOST) Veterans Affairs Cooperative Studies Program No. 453, is a prospective, randomized, two arm, double blind study of patients with end stage renal disease (ESRD) or advanced chronic kidney disease (ACKD, defined as an estimated creatinine clearance of 30 ml/min or less). Its primary objective is to determine whether administration of high doses of three vitamins, folic acid, vitamin B6 and vitamin B12, to lower the high plasma homocysteine levels, will reduce all cause mortality. The secondary objectives are to examine whether the treatment lowers the incidence of myocardial infarction, stroke, amputation of a lower extremity, a composite of death and the foregoing three events, the plasma homocysteine level, and, in ESRD patients undergoing hemodialysis, thrombosis of the vascular access. A unique feature of this trial is that after initial evaluation at enrollment and one return visit the follow up is exclusively by phone (or, if necessary, by mail). The subject is contacted every three months throughout the duration of the study from a central location. The study drug is shipped to the patient from a central location rather supplied locally. In a two year enrollment period, 2006 patients are to be enrolled. The duration of the observation period is four to six years. Data will be stored and analyzed at a coordinating center. The study design has the power to detect a reduction in all cause mortality rate of 17%. Issues related to the unique features of the design of this study are discussed.

Lack of association between early atherosclerotic carotid artery wall lesions and serum level of homocysteine

The present study evaluated the possible association of high serum levels of homocysteine with ultrasonographic manifestations of carotid atherosclerosis in 65-year-old Finnish subjects drawn from a population-based cohort. Carotid ultrasonographic measurements were performed on 54 diabetic subjects, 97 subjects with impaired glucose tolerance and 57 normoglycaemic subjects. There were no statistically significant differences between the groups in the homocysteine levels. The median homocysteine level was higher in the subjects with a history of myocardial infarction (MI) (n=9) than in the subjects with no history of MI (14.8 [range 8.7—18.3] vs.12.3 [range 6.4—49.0] µmol/L, p=0.045). In the subjects without a history of MI or stroke, the maximal intima-media thickness (IMT) of the common carotid artery did not differ in the homocysteine quintiles. There was no association between the number of atheromatous plaques and the homocysteine level. In conclusion, although high levels of serum homocysteine were not associated with early atherosclerotic changes (i.e. increased carotid IMT or the number of plaques), high homocysteine concentrations were associated with advanced atherosclerosis (i.e. a history of MI).

Homocysteine in Renal Injury

BACKGROUND

Homocysteine (Hcy) is an intermediate of methionine metabolism. Hyperhomocysteinemia (HHcy) can result from a deficiency in the enzymes or vitamin cofactors required for Hcy metabolism. Patients with renal disease tend to be hyperhomocysteinemic, particularly as renal function declines, although the underlying cause of HHcy in renal disease is not entirely understood.

SUMMARY

HHcy is considered a risk or pathogenic factor in the progression of chronic kidney disease (CKD) as well as the cardiovascular complications.

KEY MESSAGES

In this review, we summarize both clinical and experimental findings that reveal the contribution of Hcy as a pathogenic factor to the development of CKD. In addition, we discuss several important mechanisms mediating the pathogenic action of Hcy in the kidney, such as local oxidative stress, endoplasmic reticulum stress, inflammation and hypomethylation.

Long-term prognostic significance of homocysteine in middle-aged and elderly

OBJECTIVE

We investigated the association among increased levels of plasma homocysteine (Hcy), all-cause mortality, and cardiovascular events.

METHODS

Hcy was measured in 670 middle-aged and elderly subjects with no previous manifest cardiovascular disease. The follow-up period was 15 years.

RESULTS

Subjects with Hcy ≥ 10.8 μmol/l (n = 231) had a significant higher incidence of all-cause mortality (p < 0.001) and CV events (p < 0.001) compared with subjects with Hcy < 10.8 μmol/l (n = 439). However, there was no association on high levels of Hcy and VTE events or stroke.

CONCLUSION

Increased levels of Hcy are associated with all-cause mortality and CV events.

The effect of B vitamin supplementation on wound healing in type 2 diabetic mice

The aim of this study was to test the effects of B-group vitamin supplements on wound healing in diabetic mice. The mice in the experimental group were treated daily with 1 g/L B6, 1.25 mg/L B12, and 62.5 mg/L folic acid in their drinking water. Full-thickness excision wounds were created with 6-mm skin biopsy punches. Each wound closure was digitally photographed. Beginning on day 3 after wounding, the wound area in the diabetic mice was statistically larger than that of normal mice (p<0.05 vs diabetic mice). The diabetic mice treated with B vitamins displayed accelerated wound closure on day 3 (wound area 42.8 ± 11.3%, p<0.05). On day 9 after wounding, the wound area in the diabetic mice was also statistically larger than that of normal mice (p<0.05 vs diabetic mice). The diabetic mice treated with B vitamins displayed accelerated wound closure on day 3 (wound area 13.2 ± 16.8%, p<0.05). In addition, the high glucose level in the diabetic animals decreased significantly in response to B vitamin treatment. In conclusion, the results of this study indicate that B vitamin supplementation may improve wound healing in diabetic mice.