Homocysteine and coronary atherosclerosis

Atherogenic Effect of Homocysteine, a Biomarker of Inflammation and Its Treatment

Hyperhomocysteinemia (HHcy) is an independent risk factor for atherosclerosis. Ischemic stroke and heart disease, coronary heart disease, and cardiovascular disease are events resulting from long-lasting and silent atherosclerosis. This paper deals with the synthesis of homocysteine (Hcy), causes of HHcy, mechanism of HHcy-induced atherosclerosis, and treatment of HHcy. Synthesis and metabolism of Hcy involves demethylation, transmethylation, and transsulfuration, and these processes require vitamin B 6 and vitamin B 12 folic acid (vitamin B 9 ). Causes of HHcy include deficiency of vitamins B 6 , B 9 , and B 12 , genetic defects, use of smokeless tobacco, cigarette smoking, alcohol consumption, diabetes, rheumatoid arthritis, low thyroid hormone, consumption of caffeine, folic acid antagonist, cholesterol-lowering drugs (niacin), folic acid antagonist (phenytoin), prolonged use of proton pump inhibitors, metformin, and hypertension. HHcy-induced atherosclerosis may be mediated through oxidative stress, decreased availability of nitric oxide (NO), increased expression of monocyte chemoattractant protein-1, smooth muscle cell proliferation, increased thrombogenicity, and induction of arterial connective tissue. HHcy increases the generation of atherogenic biomolecules such as nuclear factor-kappa B, proinflammatory cytokines (IL-1β, IL-6, and IL-8), cell adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selection), growth factors (IGF-1 and TGF-β), and monocyte colony-stimulating factor which lead to the development of atherosclerosis. NO which is protective against the development of atherosclerosis is reduced by HHcy. Therapy with folic acid, vitamin B 6 , and vitamin B 12 lowers the levels of Hcy, with folic acid being the most effective. Dietary sources of folic acid, vitamin B 6 , vitamin B 12 , omega-3 fatty acid, and green coffee extract reduce Hcy. Abstaining from drinking coffee and alcohol, and smoking also reduces blood levels of Hcy. In conclusion, HHcy induces atherosclerosis by generating atherogenic biomolecules, and treatment of atherosclerosis-induced diseases may be by reducing the levels of Hcy.

Amino Acids during Pregnancy and Offspring Cardiovascular-Kidney-Metabolic Health

Amino acids are essential for normal pregnancy and fetal development. Disruptions in maternal amino acid metabolism have been associated with various adult diseases later in life, a phenomenon referred to as the developmental origins of health and disease (DOHaD). In this review, we examine the recent evidence highlighting the significant impact of amino acids on fetal programming, their influence on the modulation of gut microbiota, and their repercussions on offspring outcomes, particularly in the context of cardiovascular-kidney-metabolic (CKM) syndrome. Furthermore, we delve into experimental studies that have unveiled the protective effects of therapies targeting amino acids. These interventions have demonstrated the potential to reprogram traits associated with CKM in offspring. The discussion encompasses the challenges of translating the findings from animal studies to clinical applications, emphasizing the complexity of this process. Additionally, we propose potential solutions to overcome these challenges. Ultimately, as we move forward, future research endeavors should aim to pinpoint the most effective amino-acid-targeted therapies, determining the optimal dosage and mode of administration. This exploration is essential for maximizing the reprogramming effects, ultimately contributing to the enhancement of cardiovascular-kidney-metabolic health in offspring.

Mechanism of homocysteine-mediated endothelial injury and its consequences for atherosclerosis

Homocysteine (Hcy) is an intermediate amino acid formed during the conversion from methionine to cysteine. When the fasting plasma Hcy level is higher than 15 μmol/L, it is considered as hyperhomocysteinemia (HHcy). The vascular endothelium is an important barrier to vascular homeostasis, and its impairment is the initiation of atherosclerosis (AS). HHcy is an important risk factor for AS, which can promote the development of AS and the occurrence of cardiovascular events, and Hcy damage to the endothelium is considered to play a very important role. However, the mechanism by which Hcy damages the endothelium is still not fully understood. This review summarizes the mechanism of Hcy-induced endothelial injury and the treatment methods to alleviate the Hcy induced endothelial dysfunction, in order to provide new thoughts for the diagnosis and treatment of Hcy-induced endothelial injury and subsequent AS-related diseases.

A Potential Strategy for Atherosclerosis Prevention in Modernizing China - Hyperhomocysteinemia, MTHFR C677T Polymorphism and Air Pollution (PM2.5) on Atherogenesis in Chinese Adults

BACKGROUND

Atherosclerosis is one of the most important global health hazards and air pollution (AP, PM2.5) has been implicated. In addition to traditional risk factors hyperhomocysteinemia (HC) has been recognized in many parts of China related to risk of stroke.

METHODS

To evaluate the impact of HC (homocysteine >14μmol/l) and PM2.5 air pollution on atherogenesis in modernizing China, we studied 756 asymptomatic Chinese in China from 1998-2007. PM2.5 exposure, HC, folate, and methylenetetrahydrofolate reductase (MTHFR) C/T genotype were evaluated. Brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. Locations were categorized as zones 1, 2 and 3, with increasing PM2.5 exposure.

RESULTS

HC was higher (19.4±13.1 and 27.1±25.1μmol/l) in high PM2.5-polluted zones 2 and 3 than in zone 1 (9.7±4.5μmol/l, p<0.0015). The top HC tertile was characterized by lower folate and vitamin B12, but a higher proportion of the MTHFR TT genotype, Metabolic Syndrome (MS) and PM2.5 level (p=0.0018). FMD was significantly lower (7.3±2.3%) and carotid IMT thicker (0.63±0.12mm) in the top HC tertile, compared with low HC tertile (8.4±2.5%, p<0.0001; 0.57±0.1mm, p<0.0001 respectively). Similar differences in FMD and IMT were seen in zones 2 and 3, compared with zone 1 (p<0.0001). On multivariate regression, HC was related to male gender (beta=0.106, p=0.021), MTHFR-TT (beta=0.935, p<0.0001), locations (beta=0.230, p<0.0001) and folate-MTHFR interaction (beta=-0.566, p<0.0001). FMD was related to age (beta= -0.221; p<0.0001), male gender (beta= -0.194, p=0.001) PM2.5 and location (beta=-0.285 to -0.303, p<0.0001). Carotid IMT was related to PM2.5 (beta=0.173, p<0.0001), HC (0.122, p=0.006) but not to MTHFR or location, independent of age, gender, MS, and LDL-C. No significant HC-PM2.5 interaction effect on FMD and IMT was observed.

CONCLUSION

HC and PM2.5 pollution but not MTHFR genotype were both related to carotid IMT, independent of other traditional risk factors. This has potential implications in dietary and AP strategies for atherosclerosis prevention in China.

Differential effects of hyperhomocysteinemia on the lipid profiles and lipid ratios between patients with and without coronary artery disease: A retrospective observational study

This study aimed to investigate the differential effects of hyperhomocysteinemia (HHcy) on lipid profiles and lipid ratios between patients with coronary artery disease (CAD) and without CAD. The data of 872 CAD patients and 774 non-CAD controls were extracted from the information system of hospitalized patients. Serum homocysteine (Hcy), total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (Apo) AI, and ApoB concentrations were detected. HHcy was defined as a serum level of Hcy ≥ 15 μmol/L. The CAD patients had lower levels of HDL-C and ApoAI and higher levels of Hcy than the controls (P < .05). Serum TGs and HDL-C were negatively correlated with Hcy in controls. Serum HDL-C and ApoAI were negatively correlated with Hcy, and the ratios of TC/HDL-C, TG/HDL-C, LDL/HDL-C, and ApoB/ApoAI were positively correlated with Hcy in the CAD patients (P < .05). Although the trends for HHcy to decrease the lipid profiles were not different between the CAD and controls (Pinteraction > 0.05), CAD with HHcy had lower HDL-C and ApoAI levels than those of subjects with normal Hcy; controls with HHcy had lower TC, LDL-C, and ApoB levels than those of subjects with normal Hcy (P < .05). There were different HHcy trends affecting the ratios of TC/HDL-C and LDL/HDL-C between the CAD patients and controls (Pinteraction for TC/HDL-C = 0.025; Pinteraction for LDL/HDL-C = 0.033). CAD patients with HHcy had a higher ratio of TC/HDL-C (P = .022) and LDL/HDL-C (P = .045) than those of patients with normal Hcy, but in the controls, the subjects with HHcy exhibited a trend toward a decreased ratio of TC/HDL-C (P = .481) and LDL/HDL-C (P = .303). There were differential effects of HHcy on the lipid ratios between CAD and non-CAD patients. HHcy was related to higher ratios of TC/HDL-C and LDL/HDL-C in patients with CAD.

Erectile Dysfunction: Pharmacological Pathways with Understudied Potentials

Erectile dysfunction (ED) is a public health concern worldwide. In the past, it was perceived as a phenomenon attributed to age advancement. However, more individuals are affected every year that do not fall under that age criterion. Epidemiological research revealed that this abnormality has an association with endothelial dysfunction connected to several cardiovascular (CV) risk factors. Currently, ED is interpreted as a clinical marker for future adverse events and not only as a present health issue that negatively affects the quality of life. The management of ED involves lifestyle modifications, therapeutic optimization for comorbid conditions, and pharmacological and psychosexual therapy. Phosphodiesterase type 5 (PDE5) inhibitors are the first-line pharmacological agents to be prescribed for such a condition. Nonetheless, other pharmacological pathways and agents remain underinvestigated or were investigated at some stage. This review aimed to present to future researchers interested in this field with some pharmacological agents that showed favorable effects on a limited number of studies on human subjects or experimental models.

Plasma Cell-Free DNA as a Novel Biomarker for the Diagnosis and Monitoring of Atherosclerosis

Atherosclerosis (AS) is the leading cause of cardiovascular diseases (CVDs) with a high rate of mortality worldwide. Plasma cell-free DNA (cfDNA), mainly originating from apoptosis, necrosis, and active secretion, has been recognized as a promising biomarker for the diagnosis and prognosis of multiple cancers, whereas there are no reports about cfDNA in CVDs. Here, we found an increased quantity and decreased integrity of cfDNA (cfDI) in the serum from AS patients compared with normal controls. Moreover, the reduced cfDI is inversely correlated with serum LDL levels, carotid plaque size, and carotid plaque thickness in the progression of AS. Consistently, in vivo experiments confirmed that the release and cleavage of cfDNA were increased concomitantly with the development and progression of AS in ApoE⁻/⁻ mice. Our study sheds light on the potential of cfDNA and cfDI as molecular biomarkers for detecting and monitoring AS.

Extensive Thiol Profiling for Assessment of Intracellular Redox Status in Cultured Cells by HPLC-MS/MS

Oxidative stress may contribute to the pathology of many diseases, and endogenous thiols, especially glutathione (GSH) and its metabolites, play essential roles in the maintenance of normal redox status. Understanding how these metabolites change in response to oxidative insult can provide key insights into potential methods of prevention and treatment. Most existing methodologies focus only on the GSH/GSH disulfide (GSSG) redox couple, but GSH regulation is highly complex and depends on several pathways with multiple redox-active sulfur-containing species. In order to more fully characterize thiol redox status in response to oxidative insult, a high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) method was developed to simultaneously determine seven sulfur-containing metabolites, generating a panel that systematically examines several pathways involved in thiol metabolism and oxidative stress responses. The sensitivity (LOQ as low as 0.01 ng/mL), accuracy (88–126% spike recovery), and precision (≤12% RSD) were comparable or superior to those of existing methods. Additionally, the method was used to compare the baseline thiol profiles and oxidative stress responses of cell lines derived from different tissues. The results revealed a previously unreported response to oxidative stress in lens epithelial (B3) cells, which may be exploited as a new therapeutic target for oxidative-stress-related ocular diseases. Further application of this method may uncover new pathways involved in oxidative-stress-related diseases and endogenous defense mechanisms.

Mechanism of cell death of endothelial cells regulated by mechanical forces

Cell death of endothelial cells (ECs) is a common devastating consequence of various vascular-related diseases. Atherosclerosis, hypertension, sepsis, diabetes, cerebral ischemia and cardiac ischemia/reperfusion injury, and chronic kidney disease remain major causes of morbidity and mortality worldwide, in which ECs are constantly subjected to a great amount of dynamic changed mechanical forces including shear stress, extracellular matrix stiffness, mechanical stretch and microgravity. A thorough understanding of the regulatory mechanisms by which the mechanical forces controlled the cell deaths including apoptosis, autophagy, and pyroptosis is crucial for the development of new therapeutic strategies. In the present review, experimental and clinical data highlight that nutrient depletion, oxidative stress, tumor necrosis factor-α, high glucose, lipopolysaccharide, and homocysteine possess cytotoxic effects in many tissues and induce apoptosis of ECs, and that sphingosine-1-phosphate protects ECs. Nevertheless, EC apoptosis in the context of those artificial microenvironments could be enhanced, reduced or even reversed along with the alteration of patterns of shear stress. An appropriate level of autophagy diminishes EC apoptosis to some extent, in addition to supporting cell survival upon microenvironment challenges. The intervention of pyroptosis showed a profound effect on atherosclerosis. Further cell and animal studies are required to ascertain whether the alterations in the levels of cell deaths and their associated regulatory mechanisms happen at local lesion sites with considerable mechanical force changes, for preventing senescence and cell deaths in the vascular-related diseases.

The prevalence, relative risk factors and MTHFR C677T genotype of H type hypertension of the elderly hypertensives in Shanghai, China: a cross-section study : Prevalence of H type hypertension

Background

H type hypertension is defined as homocysteine (Hcy) ≥ 10 μmol/L in combination with primary hypertension. Studies demonstrated that the existence of hyperhomocysteine (HHcy) in hypertensive exacerbates the poor outcome of cardiocerebral incidents. This study was to investigate the current epidemic situation of H type hypertension and determine the risk factors in order to find intervention targets for H type hypertensives.

Methods

We conducted a cross-sectional study using cluster sampling design in Shanghai, China from July 2019 and April 2020. 23,652 patients with primary hypertension were enrolled in this study. Their medical information was recorded, and the level of Hcy concentrations and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms were detected.

Results

In total, 22,731 of 23,652 patients were recorded. The mean age was 68.9 ± 8.6 y and 43% were men. 80.0% of the enrolled patients had H type hypertension. The frequency of allele T was 40.9%, and the proportions of the CC, CT, and TT genotypes were 36.1%, 46.0%, and 17.9%, respectively. Compared with the TT genotype, the plasma Hcy concentration levels were lower in patients with the CC/CT genotype (18.96 ± 13.48 μmol/L vs. 13.62 ± 5.20/14.28 ± 5.36, F = 75.04, p < 0.01). The risk for H type hypertension was higher in elderly people. Men had ~ 5.55-fold odds of H type hypertension compared with women. Patients with CT genotype and TT genotype had ~ 1.36- and ~ 2.76-fold odds of H type hypertension compared with those with CC genotype, respectively. Smoking and diabetes were not significantly associated with H type hypertension.

Conclusions

The prevalence of H type hypertension in patients with primary hypertension was 80.0%, which was higher than the 75% found in prior report in China. Age, gender, and MTHFR C677T polymorphisms rather than smoking and diabetes were independently associated with H type hypertension.

Chronoeffects of the Herbal Medicines Puerariae radix and Coptidis rhizoma in Mice: A Potential Role of REV-ERBα

Identifying drugs with dosing time-dependent effects (chronoeffects) and understanding the underlying mechanisms would help to improve drug treatment outcome. Here, we aimed to determine chronoeffects of the herbal medicines Puerariae radix (PR) and Coptidis rhizoma (CR), and investigate a potential role of REV-ERBα as a drug target in generating chronoeffects. The pharmacological effect of PR on hyperhomocysteinemia in mice was evaluated by measuring total homocysteine, triglyceride levels and lipid accumulation. PR dosed at ZT10 generated a stronger effect on hyperhomocysteinemia than drug dosed at ZT2. Furthermore, PR increased the expression levels of REV-ERBα target genes Bhmt, Cbs and Cth (encoding three key enzymes responsible for homocysteine catabolism), thereby alleviating hyperhomocysteinemia in mice. Moreover, CR attenuated chronic colitis in mice in a dosing time-dependent manner based on measurements of disease activity index, colon length, malondialdehyde/myeloperoxidase activities and IL-1β/IL-6 levels. ZT10 dosing generated a stronger anti-colitis effect as compared to ZT2 dosing. This was accompanied by lower production of colonic inflammatory cytokines (i.e., Nlrp3, IL-1β, IL-6, Tnf-α and Ccl2, REV-ERBα target genes) in colitis mice dosed at ZT10. The diurnal patterns of PR and CR effects were respectively consistent with those of puerarin (a main active constituent of PR, a REV-ERBα antagonist) and berberine (a main active constituent of CR, a REV-ERBα agonist). In addition, loss of Rev-erbα in mice abolished the dosing time-dependency in PR and CR effects. In conclusion, the therapeutic effects of PR and CR depend on dosing time in mice, which are probably attributed to diurnal expression of REV-ERBα as the drug target. Our findings have implications for improving therapeutic outcomes of herbal medicines with a chronotherapeutic approach.

Development of a HPLC-MS/MS method for assessment of thiol redox status in human tear fluids

Oxidative stress is reported to be part of the pathology of many ocular diseases. For the diagnosis of ocular diseases, tear fluid has unique advantages. Although numerous analytical methods exist for the measurement of different types of biomolecules in tear fluid, few have been reported for comprehensive understanding of oxidative stress-related thiol redox signaling. In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to determine a panel of twelve metabolites that systematically covered several thiol metabolic pathways. With optimization of MS/MS parameters and HPLC mobile phases, this method was sensitive (LOQ as low as 0.01 ng/ml), accurate (80-125% spike recovery) and precise (<10% RSD). This LC-MS/MS method combined with a simple tear fluid collection with Schirmer test strip followed by ultrafiltration allowed the high-throughput analysis for efficient determination of metabolites associated with thiol redox signaling in human tear fluids. The method was then applied to a small cohort of tear fluids obtained from healthy individuals. The method presented here provides a new technique to facilitate future work aiming to determine the complex thiol redox signaling in tear fluids for accurate assessment and diagnosis of ocular diseases.

Recreational Nitrous Oxide Abuse: Prevalence, Neurotoxicity, and Treatment

Nitrous oxide (N₂O), also known as "laughing gas," is a colorless, nonirritating gas. Clinically, it is widely used as an inhaled anesthetic, analgesic, and anxiolytic. In recent years, recreational abuse of N₂O has become increasingly common, especially among young adults and adolescents, but many of them lack awareness of the possible side effects associated with this drug. N₂O abuse can damage multiple systems, especially the nervous system, but the exact mechanism of N₂O toxicity remains controversial. At present, an increasing number of cases of nervous system damage caused by N₂O abuse have been reported both at home and abroad. Discontinuation of N₂O use and timely supplementation with vitamin B12 are essential for a good prognosis. Long-term abuse without timely treatment will eventually lead to irreversible neurological damage. In this article, we discuss the epidemiology of N₂O abuse, neurotoxicity mechanisms, clinical manifestations, relevant auxiliary examinations, treatments, and prognosis to improve social awareness of N₂O exposure risk, especially among users and clinicians.

The Relation between Homocysteine Levels in Patients with Acute Coronary Syndrome and Grace Score

Objectives

This study investigated the correlation between homocysteine levels in patients with Acute Coronary Syndrome and GRACE Score.

Methods

This study included 191 cases -140 Non-ST MI cases and 51 MI with ST-elevation cases in Şişli Etfal Training and Research Hospital Coronary Intensive Care Unit between December 2008 and March 2010. Homocysteine was measured by immulite 2000 device, using kemiluminesans method and competitive immunoassay principle and a kit by DPC was used during the measurement. The reference range given by the producing company was between 5-15 Mmol/L for male and female adults. The patients were classified into three risk groups as low, medium and high on the basis of the criteria identified in GRACE risk score: age, heart rate, systolic blood pressure, serum creatine levels, Killip classification, cardiac arrest on admission, increased cardiac enzymes and ST segment depression. The relation between homocysteine levels in patients with Acute Coronary Syndrome and GRACE risk score was evaluated.

Results

In the Non-ST MI group, a statistically-moderate positive correlation was seen between homocysteine and GRACE risk score during the study (p<0.05). However, in the MI with ST-elevation group, no correlation was found between homocysteine and GRACE risk score (p>0.05). Overall, despite the low figures, a meaningful positive relation was observed between homocysteine and GRACE risk score in all cases.

Conclusion

Homocysteine is independent of other classic risk factors for cardiovascular diseases. Therefore, we believe that routine plasma homocysteine levels should be checked when evaluating risk factors for Atherosclerotic Coronary Artery disease.

Copolymer-Based Fluorescence Nanosensor for In Situ Imaging of Homocysteine in the Liver and Kidney of Diabetic Mice

Homocysteine (Hcy) is one of the important biomarkers of clinical diagnosis, which is closely related to the occurrence and development of many diseases. Current analysis methods have difficulties in detecting Hcy in cells and living organisms. As a powerful technique, fluorescence methods combined the laser confocal imaging technology can achieve real-time visual tracking in cells and in vivo. Herein, we establish a conjugated copolymer-based fluorescence nanosensor (DPA-PFNP-Cu(II)) using the connected 2,7-dibromofluorene and 4,7-bis (2-bromothiophen-5-yl)-2-1-3-benzothiadiazole as the main chain. The competitive coordination between Hcy and Cu(II) allows the fluorescence of the polymer off to on. Finally, the nanosensor is applied for in situ imaging of Hcy levels in the kidney and liver of diabetic mice and is found that Hcy levels were positively correlated with the degree of diabetes. Notably, the depth of tissue penetration of the nanosensor enables Hcy detection of the liver and kidney through in vivo imaging without damage. Two-photon imaging and in vivo imaging achieve consistent results, which correct each other, improving the accuracy of the test result. The present works provide a new imaging technique for studying the occurrence and development of diabetes and screening of new drugs for treatment at the living level.

Cardiovascular Consequences of Autoimmune Rheumatic Diseases

The increased risk of cardiovascular disease (CVD) among patients with autoimmune rheumatic diseases such as rheumatoid arthritis, spondyloarthritis and systemic lupus erythematosus has been extensively documented. Sub-clinical atherosclerosis can be assessed using various non-invasive imaging techniques. However, the mechanisms underlying the higher risk of atherosclerotic CVD in patients with autoimmune rheumatic diseases are not fully known, although they seem to include chronic low-grade systemic inflammation leading to prolonged endothelial activation, accompanied by a pro-thrombotic/pro-coagulant and autoantibody state. Furthermore, sub-clinical atherosclerosis is also influenced by other traditional risk factors for CVD. Including the individual components of the metabolic syndrome (MetS: obesity, impaired glucose metabolism, dyslipidemia and high blood pressure), the degree of which is higher in these patients than in controls. The aim of this narrative review is to discuss the CV manifestations and risk factors involved in the increased risk of CVD among patients with autoimmune rheumatic diseases.

Increased Expression Level of Long Noncoding RNA H19 in Plasma of Patients with Myocardial Infarction

Long noncoding RNAs (lncRNAs) are lengthy noncoding transcripts which are actively involved in crucial cellular pathways. Tissue-specific expression of lncRNAs besides its secretion into the body fluids, has made lncRNAs in attention as biomarkers of the diseases. According to the role of lncRNAs, especially H19 in cardiac regeneration, it is not surprising if their altered expression levels lead to cardiac diseases. In the present study, the relative expression of H19 was compared in the plasma of atherosclerotic myocardial infarction and control individuals by real time-PCR, and data were normalized using GAPDH. The association of plasma level of lipid and homocystine with H19 expression was also considered. The potential of H19 to discriminate the case from control was studied using the ROC analysis. We found that the plasma level of H19 transcript significantly increased in the plasma of patients in comparison with the control group. Additionally, the relative expression level of H19 was directly associated with the plasma homocystine level. The relative expression of H19 at threshold of 0.3 showed 70% sensitivity and 94% specificity to discriminate cases from controls. This study revealed that the expression level of H19 may be considered as a biomarker of myocardial infarction, although further studies are needed to generalize this finding.

Maternal Fructose Intake Increases Liver H2 S Synthesis but Exarcebates its Fructose-Induced Decrease in Female Progeny

SCOPE

Fructose intake from added sugars correlates with the epidemic rise in metabolic syndrome and cardiovascular diseases (CVD). However, consumption of beverages containing fructose is allowed during gestation. Homocysteine (Hcy) is a well-known risk factor for CVD while hydrogen sulfide (H₂ S), a product of its metabolism, has been proved to exert opposite effects to Hcy.

METHODS AND RESULTS

First, it is investigated whether maternal fructose intake produces subsequent changes in Hcy metabolism and H₂ S synthesis of the progeny. Carbohydrates are supplied to pregnant rats in drinking water (10% wt/vol) throughout gestation. Adult female descendants from fructose-fed, control or glucose-fed mothers are studied. Females from fructose-fed mothers have elevated homocysteinemia, hepatic H₂ S production, cystathionine γ-lyase (CSE) (the key enzyme in H₂ S synthesis) expression and plasma H₂ S, versus the other two groups. Second, it is studied how adult female progeny from control (C/F), fructose- (F/F), and glucose-fed (G/F) mothers responded to liquid fructose and compared them to the control group (C/C). Interestingly, hepatic CSE expression and H₂ S synthesis are diminished by fructose intake, this effect being more pronounced in F/F females.

CONCLUSION

Maternal fructose intake produces a fetal programming that increases hepatic H₂ S production and, in contrast, exacerbates its fructose-induced drop in female progeny.

Atypical Antipsychotic Exposure May Not Differentiate Metabolic Phenotypes of Patients with Schizophrenia

STUDY OBJECTIVE

Patients with schizophrenia are known to have higher rates of metabolic disease than the general population. Contributing factors likely include lifestyle and atypical antipsychotic (AAP) use, but the underlying mechanisms are unknown. The objective of this study was to identify metabolomic variability in adult patients with schizophrenia who were taking AAPs and grouped by fasting insulin concentration, our surrogate marker for metabolic risk.

DESIGN

Metabolomics analysis PARTICIPANTS: Ninety-four adult patients with schizophrenia who were taking an AAP for at least 6 months, with no changes in their antipsychotic regimen for the previous 8 weeks, and who did not require treatment with insulin, participated in the study. Twenty age- and sex-matched nonobese (10 subjects) and obese (10 subjects) controls without cardiovascular disease or mental health diagnoses were used to match the body mass index (BMI) range of the patients with schizophrenia to account for metabolite concentration differences attributable to BMI.

MEASUREMENTS AND MAIN RESULTS

Existing serum samples were used to identify aqueous metabolites (to differentiate fasting insulin concentration quartiles) and fatty acids with quantitative nuclear magnetic resonance and gas chromatography methods, respectively. To exclude metabolites from our pathway mapping analysis that were due to variability in weight, we also subjected serum samples from the nonobese and obese controls to the same analyses. Patients with schizophrenia had a median age of 47.0 years (interquartile range 41.0-52.0 years). Using a false discovery rate threshold of less than 25%, 10 metabolites, not attributable to weight, differentiated insulin concentration quartiles in patients with schizophrenia and identified variability in one-carbon metabolism between groups. Patients with higher fasting insulin concentrations (quartiles 3 and 4) also trended toward higher levels of saturated fatty acids compared with patients with lower fasting insulin concentrations (quartiles 1 and 2).

CONCLUSION

Our results illustrate the utility of metabolomics to identify pathways underlying variable fasting insulin concentration in patients with schizophrenia. Importantly, no significant difference in AAP exposure was observed among groups, suggesting that current antipsychotic use may not be a primary factor that differentiates middle-aged adult patients with schizophrenia by fasting insulin concentration.

Influence Variation of Tempe Gembus (An Indonesian Fermented Food) on Homocysteine and Malondialdehyde of Rats Fed an Atherogenic Diet

Background and Aims: Atherosclerosis has become a prominent health problem in Indonesia. Based on food as medicine concept, tempe gembus (a fermented food from Indonesia) is well known having the content of nutrient that influences atherosclerosis parameter. Research aimed to prove the influence of different variation of tempe gembus that was given without additional treatment (X1), with the steam blanching heating (X2), and was added the bromelain enzyme (X3) to the level of serum Homocysteine (Hcy) and Malondialdehyde (MDA) of rat’s blood that was given the atherogenic diet.

Material and Methods: The research of posttest randomized controlled group design on 35 Sprague dawley rats were divided into two main groups as follow; they were 2 control groups (called K− and K+) and 3 treatment groups. All of the treatment groups were given tempe gembus of 25 gram/kg rat body weight.

Results: The results showed that group variation of tempe gembus had a lower mean of Hcy and MDA levels than disease group (K+). However, a significant effect of tempe gembus was only decrease in MDA level (ANOVA test p = 0.001). Treatment X1 and X3 had meaningful differences to decrease MDA levels.

Conclusion: Tempe gembus variation can decrease the MDA level significantly and decrease the Hcy level however, without statistical significance.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pleiotropic responses to methionine restriction

Methionine restriction (MR) extends lifespan across different species. The main responses of rodent models to MR are well-documented in adipose tissue (AT) and liver, which have reduced mass and improved insulin sensitivity, respectively. Recently, molecular mechanisms that improve healthspan have been identified in both organs during MR. In fat, MR induced a futile lipid cycle concomitant with beige AT accumulation, producing elevated energy expenditure. In liver, MR upregulated fibroblast growth factor 21 and improved glucose metabolism in aged mice and in response to a high-fat diet. Furthermore, MR also reduces mitochondrial oxidative stress in various organs such as liver, heart, kidneys, and brain. Other effects of MR have also been reported in such areas as cardiac function in response to hyperhomocysteinemia (HHcy), identification of molecular mechanisms in bone development, and enhanced epithelial tight junction. In addition, rodent models of cancer responded positively to MR, as has been reported in colon, prostate, and breast cancer studies. The beneficial effects of MR have also been documented in a number of invertebrate model organisms, including yeast, nematodes, and fruit flies. MR not only promotes extended longevity in these organisms, but in the case of yeast has also been shown to improve stress tolerance. In addition, expression analyses of yeast and Drosophila undergoing MR have identified multiple candidate mediators of the beneficial effects of MR in these models. In this review, we emphasize other in vivo effects of MR such as in cardiovascular function, bone development, epithelial tight junction, and cancer. We also discuss the effects of MR in invertebrates.

Iron and Folate Status in Urban and Rural Costa Rican Teenagers

This study evaluated the iron and folate status of Costa Rican adolescents and their dietary intake of these micronutrients. Hematological data, serum ferritin, serum folate and iron and folate intakes were evaluated in 307 adolescents aged 13 to 17 years. The prevalence of anemia was 4%. Iron deficiency was found in 3% of adolescents and iron-deficiency anemia in 2% or less. The prevalence of deficient serum folate levels was less than 1%. Over 50% of females and around 20% of males did not consume 66.7% of the recommended daily allowance (RDA) for iron. Iron bioavailability in the diet of urban adolescents was intermediate, whereas it was low in the diet of rural adolescents. Approximately 53% of adolescents did not consume two-thirds of the RDA for folate. It is necessary to modify adolescents’ food habits in order to ensure an adequate iron and folate intake.

4-Pyridoxic Acid in the Spent Dialysate: Contribution to Fluorescence and Optical Monitoring

Aim

In this work we estimated the contribution of the fluorescence of 4-pyridoxic acid (4-PA) to the total fluorescence of spent dialysate with the aim of evaluating the on-line monitoring of removal of this vitamin B-6 metabolite from the blood of patients with end-stage renal disease (ESRD).

Methods

Spectrofluorometric analysis of spent dialysate, collected from hemodialysis and hemodiafiltration sessions of 10 patients receiving regularly pyridoxine injections after dialysis treatment, was performed in the range of Ex/Em 220–500 nm. 4-PA in dialysate samples was identified and quantified using HPLC with fluorescent and MS/MS detection.

Results

Averaged HPLC chromatogram of spent dialysate had many peaks in the wavelength region of Ex320/Em430 nm where 4-PA was the highest peak with contribution of 42.2±17.0% at the beginning and 47.7±18.0% in the end of the dialysis. High correlation (R = 0.88–0.95) between 4-PA concentration and fluorescence intensity of spent dialysate was found in the region of Ex310-330/Em415-500 nm, respectively.

Conclusion

4-PA elimination from the blood of ESRD patients can be potentially followed using monitoring of the fluorescence of the spent dialysate during dialysis treatments.

Renal Handling of Homocysteine During Normal Pregnancy and Preeclampsia

OBJECTIVE

Maternal plasma homocysteine decreases in normal pregnancy and is significantly increased in preeclampsia. The goal of this study was to investigate the role of the maternal kidney in the changes of plasma homocysteine during normal pregnancy and preeclampsia.

METHODS

Plasma and 24-hour urine samples were collected in the same women before, during (first, second, and third trimesters), and after normal pregnancy; and in a separate cross-sectional study of normal pregnant, preeclamptic and nonpregnant women and homocysteine concentrations were measured.

RESULTS

Longitudinally, maternal plasma homocysteine decreased significantly by the first trimester compared with prepregnancy and postpartum levels (5.6 +/- 1.8 versus 6.8 +/- 0.5 and 7.4 +/- 0.4 microM, respectively, P<.05 by analysis of variance) and paralleled a significant increase in the renal clearance of homocysteine (2.9 +/- 0.4 versus 1.8 +/- 0.2 and 1.6 +/- 0.2 L/24 hours, respectively, P<.001). In addition, plasma homocysteine was significantly elevated in preeclampsia compared with normal pregnancy (4.4 +/- 0.6 versus 3.2 +/- 0.2 microM, P<.04); however, renal clearance was not different (1.2 +/- 0.1 versus 1.0 +/- 0.1 L/24 hours, P=.55).

CONCLUSION

Increases in renal clearance contribute to the decrease in plasma homocysteine during normal pregnancy. However, changes in renal handling do not appear to contribute to the increase in plasma homocysteine in preeclampsia.

Inhibition of hydrogen sulfide on the proliferation of vascular smooth muscle cells involved in the modulation of calcium sensing receptor in high homocysteine

Hyperhomocysteinemia induces the proliferation of vascular smooth muscle cells (VSMCs). Hydrogen sulfide (H2S) inhibits the phenotype switch of VSMCs and calcium-sensing receptor (CaSR) regulated the production of endogenous H2S. However, whether CaSR inhibits the proliferation of VSMCs by regulating the endogenous cystathionine-gamma-lyase (CSE, a major enzyme that produces H2S) pathway in high homocysteine (HHcy) has not been previously investigated. The intracellular calcium concentration, the concentration of H2S, the cell viability, the proliferation and the expression of proteins of cultured VSMCs from rat thoracic aortas were measured, respectively. The results showed that the [Ca(2+)]i and the expression of p-CaMK and CSE increased upon treatment with CaSR agonist. In HHcy, the H2S concentration decrease, the proliferation and migration rate increased, the expression of Cyclin D1, PCNA, Osteopontin and p-Erk1/2 increased while the α-SM actin, P21(Cip/WAK-1) and Calponin decreased. The CaSR agonist or exogenous H2S significantly reversed the changes of VSMCs caused by HHcy. In conclusion, our results demonstrated that CaSR regulate the endogenous CSE/H2S is related to the PLC-IP3 receptor and CaM signal pathways which inhibit the proliferation of VSMCs, and the latter is involved in the Erk1/2 dependent signal pathway in high homocysteine.

Hyperhomocysteinemia and Venous Thrombosis

Deep vein thrombosis (DVT) leads to venous ulcers in later life. Venous ulcers are the majority of chronic lower extremity wounds. Recent evidence suggests that hyperhomocysteinemia is an independent risk factor for venous thrombosis. Other evidence suggests that dietary supplementation with folic acids and vitamins helps to change hyper-homocysteinemia. This may be the key to wound management in the future.

Prevalence of Hyperhomocysteinemia in Vascular Disease: Comparative Study of Thrombotic Venous Disease Vis-è-Vis Occlusive Arterial Disease

Studies on hyperhomocysteinemia in vascular occlusive disease have included mostly patients with arterial occlusion. However, more recent studies have included cases of venous occlusive disease as well. Our present study is aimed at comparing the prevalence of hyperhomocysteinemia in venous occlusive disease vis-è-vis arterial occlusive disease in the North Indian urban population. Homocysteine was estimated by chemiluminescent immunoassay in 205 normal controls and 536 patients, 244 presenting with arterial occlusion and 292 with venous thrombotic disease. The mean homocysteine in patients with arterial occlusion was 21.79 ± 0.09 μmol/L (mean ± standard error of measurement), in patients with venous thrombosis was 25.53 ± 0.1 μmol/L, and in controls was 11.33 ± 0.18 μmol/L. The prevalence of hyperhomocysteinemia (> 15 μmol/L) was 56.38% in arterial occlusive disease and 54.64% in venous thrombosis. In patients with peripheral vascular occlusive disease, patients with deep venous thrombosis (DVT) had the highest mean homocysteine level (25.51 μmol/L), which was even higher (32.14 μmol/L) when associated with pulmonary embolism (PE). There is a high prevalence of hyperhomocysteinemia in arterial and venous occlusive disease. Hence, in all patients with vascular occlusive disease, hyperhomocysteinemia should be elucidated and treated. In addition, long-term follow-up is required to ascertain whether the reduction in homocysteine decreases the thrombotic events and whether homocysteine levels can actually be of prognostic or predictive value in cases of DVT with PE.

Effect of folic acid supplementation during pregnancy on gestational hypertension/preeclampsia: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of folic acid supplementation during pregnancy on the risk of gestational hypertension/preeclampsia.

METHODS

A systematic review and meta-analysis were conducted. Medline, Embase, Scopus, and the Web of Science were searched from inception to December 2014.

RESULTS

Out of 1224 potentially relevant studies, 13 studies met our inclusion criteria (2 randomized controlled trials (RCTs), 10 cohort studies, and 1 case-control study). The pooled relative risk (RR) and 95% confidence interval (CI) of the two RCTs were 0.62 (0.45-0.87) in the trial arm as compared with the placebo arm. The pooled RR was 0.92 (95% CI: 0.79-1.08) for nine cohort studies with available data on folic acid supplementation in pregnancy and gestational hypertension/preeclampsia. Pooled RR was 0.88 (95% CI: 0.76-1.02) for eight cohort studies with available data on folic acid supplementation and preeclampsia.

CONCLUSION

Whether folic acid supplementation in pregnancy can prevent the occurrence of gestational hypertension/preeclampsia remains uncertain.

Adropin is associated with hyperhomocysteine and coronary atherosclerosis

Homocysteine has been recognized as a risk factor for atherosclerosis and cardiovascular diseases. Adropin is a newly-identified energy homeostasis protein with a potential protective effect against coronary artery disease (CAD). This study attempted to measure the correlation between serum homocysteine and adropin levels in patients with CAD, and to ascertain how the two hormones could affect the severity of coronary atherosclerosis. A cohort of CAD patients who had undergone coronary angiography was prospectively recruited. The serum homocysteine and adropin levels of the patients were measured and the severity of coronary atherosclerosis was quantified with the SYNTAX score. The data were analyzed with a generalized structural equation model. In total, 170 consecutive patients were recruited with a mean serum homocysteine level of 15.9±8.3 µmol/l, and 76 (44.7%) patients were identified as hyperhomocysteinemic with a serum homocysteine level >15 µmol/l. Serum homocysteine level was found to be significantly negatively correlated with serum adropin level (r=-0.169, P=0.028). Patients with hyperhomocysteinemia had lower serum adropin levels and higher SYNTAX scores than patients without hyperhomocysteinemia. Further analysis with a generalized structural equation model showed that adropin was significantly associated with hyperhomocysteinemia (adjusted odds ratio: 0.95, 95% confidence interval: 0.93 to 0.98; P=0.002), which in turn was significantly associated with the SYNTAX score (coefficient: 4.71, 95% confidence interval: 1.39 to 8.03; P=0.005). In conclusion, the serum homocysteine level was inversely correlated with the serum adropin level in patients with CAD. A low serum adropin level was associated with hyperhomocysteinemia and more severe coronary atherosclerosis, as reflected by a higher SYNTAX score.

Sulfur amino acids and atherosclerosis: a role for excess dietary methionine

The homocysteine theory of arteriosclerosis received credence when it was shown that after a methionine load, circulating homocysteine-cysteine concentrations were higher in cardiovascular disease patients than in healthy controls. Subsequent studies showing associations between homocysteine and coronary artery disease, stroke and cognitive impairment, relied on small increases in homocysteine concentration unlike the very high homocysteine seen in the rare genetic disorders that lead to homocystinuria and much higher homocysteine levels. Subsequent studies in cell culture, animals, and humans showed that a variety of cardiovascular adverse effects of "high homocysteine" introduced either as a nonphysiological bolus or as a methionine load led to high homocysteine. We fed apolipoprotein E-deficient mice diets designed to achieve three conditions: (1) high methionine intake with normal blood homocysteine, (2) high methionine intake with B vitamin deficiency and hyperhomocysteinemia, and (3) normal methionine intake with both B vitamin deficiency and hyperhomocysteinemia. We found that the mice fed methionine-rich diets had significant atheromatous pathology in the aortic arch even with normal plasma homocysteine levels. Mice fed B vitamin-deficient diets developed severe hyperhomocysteinemia but without any increase in vascular pathology. Our findings suggest that even moderate increases in methionine intake are atherogenic in susceptible mice while high plasma homocysteine is not.

Helicobacter pylori gastritis, a presequeale to coronary plaque

Helicobacter pylori are considered the most common human pathogen colonizing gastric mucosa. Gastritis with or without H. pylori infection is associated with increase in levels of homocysteine and high-sensitivity C-reactive protein (hs-CRP) but a more pronounced increase is noted in gastritis with H. pylori infection. Increasing level of homocysteine, due to decreased absorption of vitamin B₁₂ and folic acid, together with increased CRP levels in gastritis with H. pylori infection may be the earliest event in the process of atherosclerosis and plaque formation. Retrospective study conducted at tertiary care hospital in Mumbai by Department of Biochemistry in association with Department of Surgery. Eighty patients who underwent gastroscopy in view of gastritis were subjected to rapid urease test for diagnosis of H. pylori infection. Vitamin B₁₂, folic acid, homocysteine and hs-CRP were analyzed using chemiluminescence immuno assay. Student’s t-test, Pearson’s correlation and linear regression used for statistical analysis.

Patients with H. pylori gastritis had significantly lower levels of vitamin B₁₂ (271.6±101.3 vs 390.6±176.7 pg/mL; P=0.0005), as well as higher levels of homocysteine (17.4±7.4 vs 13.8±7.8 µmol/L; P=0.037) and hs-CRP (2.5±2.9 vs 1.2±1.1 mg/L; P=0.017), than in patients without H. pylori gastritis. However, folic acid showed (8.9±3.2 vs 10.0±3.6 ng/mL; P=0.171) no significant difference.

Elevated homocysteine and hs-CRP in H. pylori gastritis may independently induce endothelial dysfunction, leading to cardiovascular pathology.

Predictors of survival in children with methymalonic acidemia with homocystinuria in Beijing, China: a prospective cohort study

OBJECTIVE

(i) To determine whether clinical features and biochemical parameters help to predict survival of methylmalonic acidemia with homocystinuria; (ii) To find the cutoff values of biochemical parameters for predicting survival of methylmalonic acidemia with homocystinuria.

DESIGN

A prospective cohort study.

SETTING

A pediatric tertiary hospital in Beijing; all patients were followed until death or June 2013.

SUBJECTS

45 pediatric patients diagnosed with methylmalonic acidemia with homocystinuria between 2006 and 2012.

OUTCOME MEASURES

The data of clinical characteristics and pretreatment biochemical parameters were collected. The Cox regression analysis was performed to identify independent risk factors for survival of patients with methylmalonic acidemia and homocystinuria. The best cutoff values for these independent factors were determined by the receiver characteristic curve.

RESULTS

Newborn onset (OR=6.856, 95%CI=2.241-20.976, P=0.001), high level of methylmalonic acid in urine (OR=1.022, 95%CI=1.011-1.033, P<0.001), and high level of urea in serum (OR=1.083, 95%CI=1.027-1.141, P=0.003) were independent negative risk factors for survival of patients with methylmalonic acidemia and homocystinuria. The cutoff values of maximum predictive accuracy of methylmalonic acid in urine and urea in serum were respectively 5.41 mmol/mmol creatinine and 7.80 mmol/L by receiver operating characteristic curve analysis.

CONCLUSIONS

The patients of methylmalonic acidemia with homocystinuria tend to have an adverse outcome if they have newborn onsets. Elevated urea and urinary methylmalonic acid are predictors of adverse outcomes for the patients. They show similar effect for predicting severe adverse prognosis. The combination of methylmalonic acid in urine concentration and urea in serum concentration provided the most accurate predictive tool.

Homocysteine levels after nitrous oxide anesthesia for living-related donor renal transplantation: a randomized, controlled, double-blind study

BACKGROUND

Nitrous oxide anesthesia increases postoperative homocysteine concentrations. Renal transplantation candidates present with higher homocysteine levels than patients with no renal disease. We designed this study to investigate if homocysteine levels are higher in subjects receiving nitrous oxide for renal transplantation compared with subjects undergoing nitrous oxide free anesthesia.

METHODS

Data from 59 patients scheduled for living-related donor renal transplantation surgery were analyzed in this randomized, controlled, blinded, parallel-group, longitudinal trial. Patients were assigned to receive general anesthesia with (flowmeter was set at 2 L/min nitrous oxide and 1 L/min oxygen) or without nitrous oxide (2 L/min air and 1 L/min oxygen). We evaluated levels of total homocysteine and known determinants, including creatinine, folate, vitamin B12, albumin, and lipids. We evaluated factor V and von Willebrand factor (vWF) to determine endothelial dysfunction and creatinine kinase myocardial band (CKMB)-mass, troponin T to show myocardial ischemia preoperatively in the holding area (T1), after discontinuation of anesthetic gases (T2), and 24 hours after induction (T3).

RESULTS

Compared with baseline, homocysteine concentrations significantly decreased both in the nitrous oxide (22.3 ± 16.3 vs 11.8 ± 9.9; P < .00001) and nitrous oxide-free groups (21.5 ± 15.3 vs 8.0 ± 5.7; P < .0001) at postoperative hour 24. The nitrous oxide group had significantly higher mean plasma homocysteine concentrations than the nitrous oxide-free group (P = .021). The actual homocysteine difference between groups was 3.8 μmol/L.

CONCLUSION

This study shows that homocysteine levels markedly decrease within 24 hours after living-related donor kidney transplantation. Patients receiving nitrous oxide have a lesser reduction, but this finding is unlikely to have a clinical relevance.

Association of plasma leptin, homocysteine and nitric oxide levels with the presence and unstability of coronary artery disease

AIM

Leptin and total homocysteine (tHcy) may participate in the pathogenesis of coronary artery disease (CAD) through nitric oxide (NO) depletion. We sought to investigate whether leptin, tHcy and NO are suitable predictors of CAD.

PATIENTS & METHODS

This study contained 50 control subjects and 50 stable and 50 unstable angina patients. Plasma leptin, tHcy and NO levels were determined using enzyme immunoassay, HPLC fluorescence and spectrophotometric methods, respectively. Other conventional risk factors were also determined.

RESULTS

Leptin and tHcy levels were highest in unstable angina patients, followed by stable angina patients and then controls (p < 0.001). Controls had significantly higher NO than patients (p <0.001). Leptin and tHcy had a positive and NO a negative association with the presence of CAD.

CONCLUSIONS

Some athrogenic effects of leptin may be mediated by affecting tHcy and NO levels. Plasma leptin, tHcy and NO levels showed significant contribution to CAD prediction and discrimination.

Hyperhomocysteinemia: related genetic diseases and congenital defects, abnormal DNA methylation and newborn screening issues

Homocysteine, a sulfur-containing amino acid derived from the methionine metabolism, is located at the branch point of two pathways of the methionine cycle, i.e. remethylation and transsulfuration. Gene abnormalities in the enzymes catalyzing reactions in both pathways lead to hyperhomocysteinemia. Hyperhomocysteinemia is associated with increased risk for congenital disorders, including neural tube closure defects, heart defects, cleft lip/palate, Down syndrome, and multi-system abnormalities in adults. Since hyperhomocysteinemia is known to affect the extent of DNA methylation, it is likely that abnormal DNA methylation during embryogenesis, may be a pathogenic factor for these congenital disorders. In this review we highlight the importance of homocysteinemia by describing the genes encoding for enzymes of homocysteine metabolism relevant to the clinical practice, especially cystathionine-β-synthase and methylenetetrahydrofolate reductase mutations, and the impairment of related metabolites levels. Moreover, a possible correlation between hyperhomocysteine and congenital disorders through the involvement of abnormal DNA methylation during embryogenesis is discussed. Finally, the relevance of present and future diagnostic tools such as tandem mass spectrometry and next generation sequencing in newborn screening is highlighted.

The neurotoxicity of nitrous oxide: the facts and "putative" mechanisms

Nitrous oxide is a widely used analgesic agent, used also in combination with anaesthetics during surgery. Recent research has raised concerns about possible neurotoxicity of nitrous oxide, particularly in the developing brain. Nitrous oxide is an N-methyl-d-aspartate (NMDA)-antagonist drug, similar in nature to ketamine, another anaesthetic agent. It has been linked to post-operative cardiovascular problems in clinical studies. It is also widely known that exposure to nitrous oxide during surgery results in elevated homocysteine levels in many patients, but very little work has investigated the long term effect of these increased homocysteine levels. Now research in rodent models has found that homocysteine can be linked to neuronal death and possibly even cognitive deficits. This review aims to examine the current knowledge of mechanisms of action of nitrous oxide, and to describe some pathways by which it may have neurotoxic effects.

Cardioprotective potential of biobased gold nanoparticles

In the present investigation, the cardioprotective nature of proanthocyanidin (PAC)-synthesized gold nanoparticles (AuNPs) is addressed in detail. There was a rapid reduction of gold metal ions by PAC and the new-genre AuNPs exhibited remarkable in vitro stability both in biological and chemical solutions. Transmission electron microscopy (TEM) indicated that the newly formed nanoparticles ranged in size from 17 to 29 nm (∼24 nm). MTT assay carried out with peripheral blood mononuclear cells demonstrated the non-toxic nature of AuNPs. PAC-synthesized AuNPs showed cardioprotective action in isoproterenol-induced myocardial injury at a lowest dosage (9 mg kg(-1)). Cardiac marker enzymes and antioxidant parameters in serum and heart tissue were also measured.

The selective electrochemical detection of homocysteine in the presence of glutathione, cysteine, and ascorbic acid using carbon electrodes

The detection of homocysteine, HCys, was achieved with the use of catecholvia1,4-Michael addition reaction using carbon electrodes: a glassy carbon electrode and a carbon nanotube modified glassy carbon electrode.