The Molecular and Cellular Effect of Homocysteine Metabolism Imbalance on Human Health

Schisandra chinensis Fructus and Its Active Ingredients as Promising Resources for the Treatment of Neurological Diseases

Neurological diseases (NDs) are a leading cause of death worldwide and tend to mainly affect people under the age of 50. High rates of premature death and disability caused by NDs undoubtedly constrain societal development. However, effective therapeutic drugs and methods are very limited. Schisandra chinensis Fructus (SCF) is the dry ripe fruit of Schisandra chinensis (Turcz.) Baill, which has been used in traditional Chinese medicine for thousands of years. Recent research has indicated that SCF and its active ingredients show a protective role in NDs, including cerebrovascular diseases, neurodegenerative diseases, or depression. The key neuroprotective mechanisms of SCF and its active ingredients have been demonstrated to include antioxidation, suppression of apoptosis, anti-inflammation, regulation of neurotransmitters, and modulation of brain-derived neurotrophic factor (BDNF) related pathways. This paper summarizes studies of the role of SCF and its active ingredients in protecting against NDs, and highlights them as promising resources for future treatment. Furthermore, novel insights on the future challenges of SCF and its active ingredients are offered.

Diagnostic Criteria and Clinical Outcomes in Sarcopenia Research: A Literature Review

By the sixth decade of life, nearly one quarter of the population has substantial muscle atrophy, or sarcopenia. Despite the creation of a standardized definition of sarcopenia by the European Working Group on Sarcopenia in Older People, variability may exist in the diagnostic criteria utilized for clinical sarcopenia research. The primary objectives of this review were to characterize diagnostic criteria used for measurement of sarcopenia in original studies, and to describe associations between sarcopenia and important clinical outcomes. We performed a literature review of the term “sarcopenia” in PubMed. Inclusion criteria were English language, original data, a clear and specific definition for diagnosing sarcopenia, and the analysis of sarcopenia’s effect on a clinical outcome. A total of 283 studies met inclusion criteria. More than half of the included sarcopenia investigations were level IV studies (54.1%), while 43.1% provided level II evidence. Under one third (27.6%) of studies examined sarcopenia with regard to surgical outcomes. In terms of diagnostic criteria for sarcopenia, 264 (93.3%) studies used measures of skeletal muscle mass, with dual energy X-ray absorptiometry (DEXA) being the most common modality (43.6%). Sarcopenia was found to be a consistent predictor of chronic disease progression, all-cause mortality, poorer functional outcomes, and postoperative complications. In conclusion, there is substantial evidence that sarcopenia impacts both medical and surgical outcomes. However, current research has utilized heterogeneous diagnostic criteria for sarcopenia. Further efforts to standardize the modalities used to diagnose sarcopenia in clinical research and practice will help strengthen our ability to study this important phenomenon.

Exercise Mitigates Alcohol Induced Endoplasmic Reticulum Stress Mediated Cognitive Impairment through ATF6-Herp Signaling

Chronic ethanol/alcohol (AL) dosing causes an elevation in homocysteine (Hcy) levels, which leads to the condition known as Hyperhomocysteinemia (HHcy). HHcy enhances oxidative stress and blood-brain-barrier (BBB) disruption through modulation of endoplasmic reticulum (ER) stress; in part by epigenetic alternation, leading to cognitive impairment. Clinicians have recommended exercise as a therapy; however, its protective effect on cognitive functions has not been fully explored. The present study was designed to observe the protective effects of exercise (EX) against alcohol-induced epigenetic and molecular alterations leading to cerebrovascular dysfunction. Wild-type mice were subjected to AL administration (1.5 g/kg-bw) and subsequent treadmill EX for 12 weeks (5 day/week@7-11 m/min). AL affected mouse brain through increases in oxidative and ER stress markers, SAHH and DNMTs alternation, while decreases in CBS, CSE, MTHFR, tight-junction proteins and cellular H2S levels. Mechanistic study revealed that AL increased epigenetic DNA hypomethylation of Herp promoter. BBB dysfunction and cognitive impairment were observed in the AL treated mice. AL mediated transcriptional changes were abolished by administration of ER stress inhibitor DTT. In conclusion, exercise restored Hcy and H2S to basal levels while ameliorating AL-induced ER stress, diminishing BBB dysfunction and improving cognitive function via ATF6-Herp-signaling. EX showed its protective efficacy against AL-induced neurotoxicity.

Impact of the 24-h ultramarathon race on homocysteine, oxidized low-density lipoprotein, and paraoxonase 1 levels in professional runners

The impact of the 24-h ultramarathon race on homocysteine (Hcy) and oxidized low-density lipoprotein (oxLDL) levels, two well-recognized cardiovascular risk factors, has not been deeply investigated. Similarly, no information exists on paraoxonase 1 (PON1), an antioxidant enzyme associated with high-density lipoproteins, which may detoxify oxLDL and Hcy-thiolactone, hence preventing their proatherogenic action. Taking this into account, a competitive 24-h ultramarathon race was organized in Reggio-Emilia (Italy) recruiting professional runners (n = 14) from the Italian Ultramarathon and Trail Association. Blood samples were collected from each participant before, during (14 h), and immediately after (24 h) the competition, thus to monitor the serum changes in Hcy, oxLDL, and PON1 levels, as well as other oxidative stress-related parameters, namely reactive oxygen metabolites (ROM) and total antioxidant capacity (PAT). As a result, a significant PON1 increase was recorded after 14 h of racing that persisted until the end of the performance. The same trend was observed for PAT values, which positively correlated to PON1 levels (R = 0.643, P<0.001). Hcy, oxLDL, and ROM remained almost unchanged throughout the competition. In conclusion, the present study suggested a protective role of PON1 in sustaining the antioxidant defense system and contrasting lipoprotein oxidative modifications over the 24-h race, and did not specifically evidence either Hcy or oxLDL accumulation in such challenging sporting events.

Therapeutic Cocktail Approach for Treatment of Hyperhomocysteinemia in Alzheimer's Disease

In the United States, Alzheimer's disease (AD) is the most common cause of dementia, accompanied by substantial economic and emotional costs. During 2015, more than 15 million family members who provided care to AD patients had an estimated total cost of 221 billion dollars. Recent studies have shown that elevated total plasma levels of homocysteine (tHcy), a condition known as hyperhomocysteinemia (HHcy), is a risk factor for AD. HHcy is associated with cognitive decline, brain atrophy, and dementia; enhances the vulnerability of neurons to oxidative injury; and damages the blood-brain barrier. Many therapeutic supplements containing vitamin B12 and folate have been studied to help decrease tHcy to a certain degree. However, a therapeutic cocktail approach with 5-methyltetrahydrofolate, methyl B12, betaine, and N-acetylcysteine (NAC) have not been studied. This novel approach may help target multiple pathways simultaneously to decrease tHcy and its toxicity substantially.

Integrative omics analysis of p53-dependent regulation of metabolism

Accumulated evidence in the last decade implies that regulation of metabolism by p53 represents a reviving mechanism vital to prevent tumorigenesis. To gain a more in-depth understanding of metabolic regulation by baseline levels of p53, we employed both metabolomics and transcriptomics analysis with human colon cancer cell-line HCT116 depleted of p53. Metabolomics analyses with UPLC/quadrupole time-of-flight mass spectrometry identified 283 significantly changed metabolites including 138 important metabolites. Transcriptomics analysis with microarray revealed 1317 differentially expressed genes. By integrated analysis of both omics data, we found nucleotides metabolism and sulfur-related metabolism are of great importance. Our study provided a pilot comprehensive view of the metabolism regulated by p53 and suggests several potential p53 targets in metabolism for further study.

Application of Metabolomics in Alzheimer's Disease

Progress toward the development of efficacious therapies for Alzheimer’s disease (AD) is halted by a lack of understanding early underlying pathological mechanisms. Systems biology encompasses several techniques including genomics, epigenomics, transcriptomics, proteomics, and metabolomics. Metabolomics is the newest omics platform that offers great potential for the diagnosis and prognosis of neurodegenerative diseases as an individual’s metabolome reflects alterations in genetic, transcript, and protein profiles and influences from the environment. Advancements in the field of metabolomics have demonstrated the complexity of dynamic changes associated with AD progression underscoring challenges with the development of efficacious therapeutic interventions. Defining systems-level alterations in AD could provide insights into disease mechanisms, reveal sex-specific changes, advance the development of biomarker panels, and aid in monitoring therapeutic efficacy, which should advance individualized medicine. Since metabolic pathways are largely conserved between species, metabolomics could improve the translation of preclinical research conducted in animal models of AD into humans. A summary of recent developments in the application of metabolomics to advance the AD field is provided below.

Chronic Mild Hyperhomocysteinemia Alters Inflammatory and Oxidative/Nitrative Status and Causes Protein/DNA Damage, as well as Ultrastructural Changes in Cerebral Cortex: Is Acetylsalicylic Acid Neuroprotective?

Homocysteine is a sulfur-containing amino acid derived from methionine metabolism. When plasma homocysteine levels exceed 10-15 μM, there is a condition known as hyperhomocysteinemia, which occur as a result of an inborn error of methionine metabolism or by non-genetic causes. Mild hyperhomocysteinemia is considered a risk factor for development of neurodegenerative diseases. The objective of the present study was to evaluate whether acetylsalicylic acid has neuroprotective role on the effect of homocysteine on inflammatory, oxidative/nitrative stress, and morphological parameters in cerebral cortex of rats subjected to chronic mild hyperhomocysteinemia. Wistar male rats received homocysteine (0.03 μmol/g of body weight) by subcutaneous injections twice a day and acetylsalicylic acid (25 mg/Kg of body weight) by intraperitoneal injections once a day from the 30th to the 60th postpartum day. Control rats received vehicle solution in the same volume. Results showed that rats subjected to chronic mild hyperhomocysteinemia significantly increased IL-1β, IL-6, and acetylcholinesterase activity and reduced nitrite levels. Homocysteine decreased catalase activity and immunocontent and superoxide dismutase activity, caused protein and DNA damage, and altered neurons ultrastructure. Acetylsalicylic acid totally prevented the effect of homocysteine on acetylcholinesterase activity and catalase activity and immunocontent, as well as the ultrastructural changes, and partially prevented alterations on IL-1β levels, superoxide dismutase activity, sulfhydryl content, and comet assay. Acetylsalicylic acid per se increased DNA damage index. In summary, our findings showed that chronic chemically induced model of mild hyperhomocysteinemia altered some parameters and acetylsalicylic acid administration seemed to be neuroprotective, at least in part, on neurotoxicity of homocysteine.

Molecular regulation of epithelial-to-mesenchymal transition in tumorigenesis (Review)

Numerous studies over the past two decades have focused on the epithelial-to-mesenchymal transition (EMT) and its role in the development of metastasis. Certain studies highlighted the importance of EMT in the dissemination of tumor cells and metastasis of epithelium-derived carcinomas. Tumor metastasis is a multistep process during which tumor cells change their morphology, and start to migrate and invade distant sites. The present review discusses the current understanding of the molecular mechanisms contributing to EMT in embryogenesis, fibrosis and tumorigenesis. Additionally, the signaling pathways that initiate EMT through transcriptional factors responsible for the activation and suppression of various genes associated with cancer cell migration were investigated. Furthermore, the important role of the epigenetic modifications that regulate EMT and the reverse process, mesenchymal-to-epithelial transition (MET) are discussed. MicroRNAs are key regulators of various intracellular processes and current knowledge of EMT has significantly improved due to microRNA characterization. Their effect on signaling pathways and the ensuing events that occur during EMT at the molecular level is becoming increasingly recognized. The current review also highlights the role of circulating tumor cells (CTCs) and CTC clusters, and their ability to form metastases. In addition, the biological properties of different types of circulating cells based on their tumor-forming potential are compared.

The Effects of Methionine-Enriched and Vitamins (Folate, Pyridoxine and Cobalamine)-Deficient Diet on Exploratory Activity in Rats - A Brief Report

The aim of this study was to evaluate the impact of increased homocysteine levels induced by methionine nutritional overload (twice as standard) and deficiency of the vitamins folate, pyridoxine and cobalamine, which plays an important role in homocysteine metabolism in anxiety-related behaviour, expressed by means of exploratory activity in rats. Twenty-three male Wistar albino rats (4 weeks old, 100±15 g body weight) were divided into three groups: control (n=8), methionine-enriched (Meth+, 7.7 g of methionine/kg chow, n=7) and methionine-enriched vitamin-deficient (Meth+Vit-, 7.7 g of methionine/ kg chow, deficient in folate, pyridoxine and cobalamine - 0.08, 0.01 and 0.01 mg/kg, n=8). All animals had free access to food and water for 30 days. Behavioural testing was performed using the elevated plus maze (EPM) test. Standard parameters for vertical exploratory activity, the number of rearings and the number of head-dippings, as well as the total exploratory activity (summarizing overall exploratory activity in the EPM) were significantly reduced following 30 days of methionine nutritional overload (p<0.05, p<0.05 and p<0.01, respectively). A methionine-enriched diet coupled with a reduction in some B vitamins resulted in a more pronounced decline in exploratory drive observed in the EPM test compared to the control (p<0.01). The decline in total exploratory activity associated with vitamin deficiency was significant compared to the Meth+ group (p<0.05). The results of this study highlight the important role of homocysteine in the modulation of exploratory activity in rats. Decreased exploratory drive induced by both a methionine-enriched and vitamin-deficient diet could be attributed to an anxiogenic effect of hyperhomocysteinemia.

Oxidative Stress in Homocystinuria Due to Cystathionine ß-Synthase Deficiency: Findings in Patients and in Animal Models

Homocystinuria is an inborn error of amino acid metabolism caused by deficiency of cystathionine ß-synthase (CBS) activity, biochemically characterized by homocysteine (Hcy) and methionine (Met) accumulation in biological fluids and high urinary excretion of homocystine. Clinical manifestations include thinning and lengthening of long bones, osteoporosis, dislocation of the ocular lens, thromboembolism, and mental retardation. Although the pathophysiology of this disease is poorly known, the present review summarizes the available experimental findings obtained from patients and animal models indicating that oxidative stress may contribute to the pathogenesis of homocystinuria. In this scenario, several studies have shown that enzymatic and non-enzymatic antioxidant defenses are decreased in individuals affected by this disease. Furthermore, markers of lipid, protein, and DNA oxidative damage have been reported to be increased in blood, brain, liver, and skeletal muscle in animal models studied and in homocystinuric patients, probably as a result of increased free radical generation. On the other hand, in vitro and in vivo studies have shown that Hcy induces reactive species formation in brain, so that this major accumulating metabolite may underlie the oxidative damage observed in the animal model and human condition. Taken together, it may be presumed that the disruption of redox homeostasis may contribute to the tissue damage found in homocystinuria. Therefore, it is proposed that the use of appropriate antioxidants may represent a novel adjuvant therapy for patients affected by this disease.

Effect of Hyperhomocysteinemia on Redox Balance and Redox Defence Enzymes in Ischemia-Reperfusion Injury and/or After Ischemic Preconditioning in Rats

Increased level of homocysteine (hHcy) in plasma is an accompanying phenomenon of many diseases, including a brain stroke. This study determines whether hyperhomocysteinemia (which is a risk factor of brain ischemia) itself or in combination with ischemic preconditioning affects the ischemia-induced neurodegenerative changes, generation of reactive oxygen species (ROS), lipoperoxidation, protein oxidation, and activity of antioxidant enzymes in the rat brain cortex. The hHcy was induced by subcutaneous administration of homocysteine (0.45 μmol/g body weight) twice a day in 8 h intervals for 14 days. Rats were preconditioned by 5 min ischemia. Two days later, 15 min of global forebrain ischemia was induced by four vessel's occlusion. The study demonstrates that in the cerebral cortex, hHcy alone induces progressive neuronal cell death and morphological changes. Neuronal damage was associated with the pro-oxidative effect of hHcy, which leads to increased ROS formation, peroxidation of lipids and oxidative alterations of cortical proteins. Ischemic reperfusion injury activates degeneration processes and de-regulates redox balance which is aggravated under hHcy conditions and leads to the augmented lipoperoxidation and protein oxidation. If combined with hHcy, ischemic preconditioning could preserve the neuronal tissue from lethal ischemic effect and initiates suppression of lipoperoxidation, protein oxidation, and alterations of redox enzymes with the most significant effect observed after prolonged reperfusion. Increased prevalence of hyperhomocysteinemia in the Western population and crucial role of elevated Hcy level in the pathogenesis of neuronal disorders makes this amino acid as an interesting target for future research. Understanding the multiple etiological mechanisms and recognition of the co-morbid risk factors that lead to the ischemic/reperfusion injury and ischemic tolerance is therefore important for developing therapeutic strategies in human brain stroke associated with the elevated level of Hcy.

Psoriasis and Cardiovascular Comorbidities: Focusing on Severe Vascular Events, Cardiovascular Risk Factors and Implications for Treatment

Psoriasis is a common and chronic inflammatory disease of the skin. It may impair the physical and psychosocial function of patients and lead to decreased quality of life. Traditionally, psoriasis has been regarded as a disease affecting only the skin and joints. More recently, studies have shown that psoriasis is a systemic inflammatory disorder which can be associated with various comorbidities. In particular, psoriasis is associated with an increased risk of developing severe vascular events such as myocardial infarction and stroke. In addition, the prevalence rates of cardiovascular risk factors are increased, including hypertension, diabetes mellitus, dyslipidemia, obesity, and metabolic syndrome. Consequently, mortality rates have been found to be increased and life expectancy decreased in patients with psoriasis, as compared to the general population. Various studies have also shown that systemic treatments for psoriasis, including methotrexate and tumor necrosis factor-α inhibitors, may significantly decrease cardiovascular risk. Mechanistically, the presence of common inflammatory pathways, secretion of adipokines, insulin resistance, angiogenesis, oxidative stress, microparticles, and hypercoagulability may explain the association between psoriasis and cardiometabolic disorders. In this article, we review the evidence regarding the association between psoriasis and cardiovascular comorbidities, focusing on severe vascular events, cardiovascular risk factors and implications for treatment.

Remote light-controlled intracellular target recognition by photochromic fluorescent glycoprobes

Development of powerful fluorescence imaging probes and techniques sets the basis for the spatiotemporal tracking of cells at different physiological and pathological stages. While current imaging approaches rely on passive probe–analyte interactions, here we develop photochromic fluorescent glycoprobes capable of remote light-controlled intracellular target recognition. Conjugation between a fluorophore and spiropyran produces the photochromic probe, which is subsequently equipped with a glycoligand “antenna” to actively localize a target cell expressing a selective receptor. We demonstrate that the amphiphilic glycoprobes that form micelles in water can selectively enter the target cell to operate photochromic cycling as controlled by alternate UV/Vis irradiations. We further show that remote light conversion of the photochromic probe from one isomeric state to the other activates its reactivity toward a target intracellular analyte, producing locked fluorescence that is no longer photoisomerizable. We envision that this research may spur the use of photochromism for the development of bioimaging probes.

Fluorescence sensing in biological environments is prone to background signal interference. Here the authors design a photochromic fluorescent glycoprobe for light-controlled photo-switchable cell imaging and photo-activated target recognition, resulting in an increased sensing precision.

Hyperhomocysteinaemia and vascular injury: advances in mechanisms and drug targets

Homocysteine is a sulphur-containing non-proteinogenic amino acid. Hyperhomocysteinaemia (HHcy), the pathogenic elevation of plasma homocysteine as a result of an imbalance of its metabolism, is an independent risk factor for various vascular diseases, such as atherosclerosis, hypertension, vascular calcification and aneurysm. Treatments aimed at lowering plasma homocysteine via dietary supplementation with folic acids and vitamin B are more effective in preventing vascular disease where the population has a normally low folate consumption than in areas with higher dietary folate. To date, the mechanisms of HHcy-induced vascular injury are not fully understood. HHcy increases oxidative stress and its downstream signalling pathways, resulting in vascular inflammation. HHcy also causes vascular injury via endoplasmic reticulum stress. Moreover, HHcy up-regulates pathogenic genes and down-regulates protective genes via DNA demethylation and methylation respectively. Homocysteinylation of proteins induced by homocysteine also contributes to vascular injury by modulating intracellular redox state and altering protein function. Furthermore, HHcy-induced vascular injury leads to neuronal damage and disease. Also, an HHcy-activated sympathetic system and HHcy-injured adipose tissue also cause vascular injury, thus demonstrating the interactions between the organs injured by HHcy. Here, we have summarized the recent developments in the mechanisms of HHcy-induced vascular injury, which are further considered as potential therapeutic targets in this condition.

LINKED ARTICLES

This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

Cardiovascular disease, which includes coronary artery disease, stroke and peripheral vascular disease, is a leading cause of death worldwide. Homocysteine is an amino acid with biological functions in methionine metabolism. A postulated risk factor for cardiovascular disease is an elevated circulating total homocysteine level. The impact of homocysteine-lowering interventions, given to patients in the form of vitamins B6, B9 or B12 supplements, on cardiovascular events has been investigated. This is an update of a review previously published in 2009, 2013, and 2015.

OBJECTIVES

To determine whether homocysteine-lowering interventions, provided to patients with and without pre-existing cardiovascular disease are effective in preventing cardiovascular events, as well as reducing all-cause mortality, and to evaluate their safety.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2017, Issue 5), MEDLINE (1946 to 1 June 2017), Embase (1980 to 2017 week 22) and LILACS (1986 to 1 June 2017). We also searched Web of Science (1970 to 1 June 2017). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of homocysteine-lowering interventions for preventing cardiovascular events with a follow-up period of one year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease.

DATA COLLECTION AND ANALYSIS

We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We calculated the number needed to treat for an additional beneficial outcome (NNTB). We measured statistical heterogeneity using the I2 statistic. We used a random-effects model. We conducted trial sequential analyses, Bayes factor, and fragility indices where appropriate.

MAIN RESULTS

In this third update, we identified three new randomised controlled trials, for a total of 15 randomised controlled trials involving 71,422 participants. Nine trials (60%) had low risk of bias, length of follow-up ranged from one to 7.3 years. Compared with placebo, there were no differences in effects of homocysteine-lowering interventions on myocardial infarction (homocysteine-lowering = 7.1% versus placebo = 6.0%; RR 1.02, 95% confidence interval (CI) 0.95 to 1.10, I2 = 0%, 12 trials; N = 46,699; Bayes factor 1.04, high-quality evidence), death from any cause (homocysteine-lowering = 11.7% versus placebo = 12.3%, RR 1.01, 95% CI 0.96 to 1.06, I2 = 0%, 11 trials, N = 44,817; Bayes factor = 1.05, high-quality evidence), or serious adverse events (homocysteine-lowering = 8.3% versus comparator = 8.5%, RR 1.07, 95% CI 1.00 to 1.14, I2 = 0%, eight trials, N = 35,788; high-quality evidence). Compared with placebo, homocysteine-lowering interventions were associated with reduced stroke outcome (homocysteine-lowering = 4.3% versus comparator = 5.1%, RR 0.90, 95% CI 0.82 to 0.99, I2 = 8%, 10 trials, N = 44,224; high-quality evidence). Compared with low doses, there were uncertain effects of high doses of homocysteine-lowering interventions on stroke (high = 10.8% versus low = 11.2%, RR 0.90, 95% CI 0.66 to 1.22, I2 = 72%, two trials, N = 3929; very low-quality evidence).We found no evidence of publication bias.

AUTHORS' CONCLUSIONS

In this third update of the Cochrane review, there were no differences in effects of homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination comparing with placebo on myocardial infarction, death from any cause or adverse events. In terms of stroke, this review found a small difference in effect favouring to homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination comparing with placebo.There were uncertain effects of enalapril plus folic acid compared with enalapril on stroke; approximately 143 (95% CI 85 to 428) people would need to be treated for 5.4 years to prevent 1 stroke, this evidence emerged from one mega-trial.Trial sequential analyses showed that additional trials are unlikely to increase the certainty about the findings of this issue regarding homocysteine-lowering interventions versus placebo. There is a need for additional trials comparing homocysteine-lowering interventions combined with antihypertensive medication versus antihypertensive medication, and homocysteine-lowering interventions at high doses versus homocysteine-lowering interventions at low doses. Potential trials should be large and co-operative.

Capillary electrophoresis coupled with chloroform-acetonitrile extraction for rapid and highly selective determination of cysteine and homocysteine levels in human blood plasma and urine

A rapid and selective method has been developed for highly sensitive determination of total cysteine and homocysteine levels in human blood plasma and urine by capillary electrophoresis (CE) coupled with liquid-liquid extraction. Analytes were first derivatized with 1,1'-thiocarbonyldiimidazole and then samples were purified by chloroform-ACN extraction. Electrophoretic separation was performed using 0.1 M phosphate with 30 mM triethanolamine, pH 2, containing 25 μM CTAB, 2.5 μM SDS, and 2.5% polyethylene glycol 600. Samples were injected into the capillary (with total length 32 cm and 50 μm id) at 2250 mbar*s and subsequent injection was performed for 30 s with 0.5 M KОН. The total analysis time was less than 9 min, accuracy was 98%, and precision was <2.6%. The LOD was 0.2 μM for homocysteine and 0.5 μM for cysteine. The use of liquid-liquid extraction allowed the precision and sensitivity of the CE method to be significantly increased. The validated method was applied to determine total cysteine and homocysteine content in human blood plasma and urine samples obtained from healthy volunteers and patients with kidney disorders.

Independent impact of plasma homocysteine levels on neurological outcome following head injury

Homocysteine (tHcy) has been hardly studied among patients with head injury. This study was to evaluate whether there is any independent impact of tHcy levels on neurological outcome following head injury in a multivariate model. Patients admitted within 24 h of injury were included in the study, along with 20 age- and gender-matched controls. Plasma levels of tHcy were measured at admission using direct immunoassay. All the variables were analyzed with respect to tHcy levels and outcome according to Glasgow Outcome Score (GOS) at 3 months. Univariate and multivariate analyses were performed using SPSS 21. There were a total of 72 patients in the study. tHcy levels were significantly higher after head injury (mean 24.03[SD ± 16.0] μmol/L), compared to matched controls (mean 16.62 [SD ± 10.4] μmol/L) (p = 0.05). Patients with severe head injury, acute SDH, or diffuse higher radiological grades had greater levels of tHcy compared to others. There was a significant relationship between tHcy level and neurological outcome. tHcy levels were significantly higher in patients who had unfavorable GOS (mean 36.22[±25.3] μmol/L), compared to those with favorable GOS (mean 22.71[±14.3] μmol/L) (P = 0.03). In multivariate analysis, tHcy level (adj. odds ratio [OR] 1.17, P = 0.05) and Glasgow Coma Scale (adj. OR 5.17, P = 0.01) had significant association with neurological outcome at 3 months independent of age, dietary habit, radiological grading and of each other. tHcy level has significant independent impact on neurological outcome and may be useful as a prognostic marker following head injury.

Homocysteine Induces Hepatic Steatosis Involving ER Stress Response in High Methionine Diet-Fed Mice

Elevated circulating homocysteine (Hcy) has been proposed to be associated with non-alcoholic fatty liver disease (NAFLD). It is also reported that Hcy causes protein misfolding in the endoplasmic reticulum (ER). In this study, we used a high methionine diet (HMD)-fed mouse model and cultured primary hepatocytes to investigate the effects of Hcy on hepatic lipids metabolism. C57BL/6J mice received either standard chow diet (CT, n = 10) or diet supplemented with 2% methionine (MET, n = 10) for 16 weeks. In in vitro experiments, cultured mouse primary hepatocytes were treated with Hcy, or Hcy combined with 4-phenylbutyric acid (4-PBA), or tunicamycin (TM), respectively. HMD-fed mice exhibited a mild increase in plasma Hcy level. There was no significant difference of body weight gain between the two groups. Nevertheless, HMD feeding increased epididymal fat/body weight ratio, elevated plasma triglyceride (TG) level, and decreased high-density lipoprotein cholesterol (HDL) level. Similarly, mice on HMD displayed higher liver/body weight ratio, plasma aspartate aminotransferase (AST) and its ratio to alanine aminotransferase (ALT), which was supported by the morphological observations of hepatic triglyceride accumulation in liver tissue as well as primary hepatocytes. Activation of the sterol response element-binding protein 1c (SREBP1c) in Hcy-treated hepatocytes with increased expression of genes involved in hepatic de novo lipogenesis was partially reduced by pretreatment of 4-PBA. Hcy-induced ER stress was also ameliorated by 4-PBA pretreatment, thus demonstrating an important role of Hcy-induced ER stress response in hepatic steatosis. These findings suggest that elevated Hcy was a critical factor in the pathogenesis of NAFLD. Activation of the ER stress response may be involved in Hcy-induced hepatic steatosis.