Basic data]

From Gut to Brain: Uncovering Potential Serum Biomarkers Connecting Inflammatory Bowel Diseases to Neurodegenerative Diseases

Inflammatory bowel diseases (IBDs) are characterized by chronic gastrointestinal inflammation due to abnormal immune responses to gut microflora. The gut-brain axis is disrupted in IBDs, leading to neurobiological imbalances and affective symptoms. Systemic inflammation in IBDs affects the brain's inflammatory response system, hormonal axis, and blood-brain barrier integrity, influencing the gut microbiota. This review aims to explore the association between dysregulations in the gut-brain axis, serum biomarkers, and the development of cognitive disorders. Studies suggest a potential association between IBDs and the development of neurodegeneration. The mechanisms include systemic inflammation, nutritional deficiency, GBA dysfunction, and the effect of genetics and comorbidities. The objective is to identify potential correlations and propose future research directions to understand the impact of altered microbiomes and intestinal barrier functions on neurodegeneration. Serum levels of vitamins, inflammatory and neuronal damage biomarkers, and neuronal growth factors have been investigated for their potential to predict the development of neurodegenerative diseases, but current results are inconclusive and require more studies.

A Hospital-Based Case-Control Study on Raised Homocysteine Level in Vitiligo Patients and Its Association With Disease Severity

Introduction Vitiligo is an acquired pigmentary disorder clinically manifested by circumscribed depigmented macules and often associated with leucotrichia. Not much is known about the biochemical abnormality occurring in vitiligo. Our study aims to determine whether serum homocysteine is raised in vitiligo patients and whether it can be used as a prognostic marker for vitiligo. Material and methods This study is a hospital-based, case-control, analytical study conducted on 70 patients of vitiligo patients. A total of 30 staff of the hospital served as control. Venous blood was withdrawn from the antecubital vein from all study participants using all aseptic precautions. Investigation of blood homocysteine levels was done in all the study participants. Scoring of vitiligo was done based on Vitiligo European Task Force (VETF) criteria which take into account body surface area, stage, and spread. Results Mean serum homocysteine level among vitiligo patients was 14.40± 5.80 micromoles/lit as compared to 10.33± 5.05 micromole/lit in control groups, and this difference was statistically significant (t-value = 3.19and p-value = 0.002). The correlation coefficient was statistically significant (correlation coefficient = 0.25 and p-value = 0.03) in between homocysteine level and stage of the disease. On multiple comparisons difference in serum homocysteine level of progressing category is significantly raised as compared to control, stable, and regressing categories. Conclusion The mean serum homocysteine level among all vitiligo patients was higher as compared to control groups. Moreover, the serum homocysteine level of active cases is significantly higher as compared to control, stable, and regressing categories. Also, serum homocysteine levels showed a positive correlation with the degree of depigmentation, i.e., stage of the disease.

Modifiable contributing factors to COVID-19: A comprehensive review

The devastating complications of coronavirus disease 2019 (COVID-19) result from an individual's dysfunctional immune response following the initial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Multiple toxic stressors and behaviors contribute to underlying immune system dysfunction. SARS-CoV-2 exploits the dysfunctional immune system to trigger a chain of events ultimately leading to COVID-19. The current study identifies eighty immune system dysfunction-enabling toxic stressors and behaviors (hereafter called modifiable contributing factors (CFs)) that also link directly to COVID-19. Each CF is assigned to one of the five categories in the CF taxonomy shown in Section 3.3.: Lifestyle (e.g., diet, substance abuse); Iatrogenic (e.g., drugs, surgery); Biotoxins (e.g., micro-organisms, mycotoxins); Occupational/Environmental (e.g., heavy metals, pesticides); Psychosocial/Socioeconomic (e.g., chronic stress, lower education). The current study shows how each modifiable factor contributes to decreased immune system capability, increased inflammation and coagulation, and increased neural damage and neurodegeneration. It is unclear how real progress can be made in combatting COVID-19 and other similar diseases caused by viral variants without addressing and eliminating these modifiable CFs.

Association of MTHFR C677T polymorphism with elevated homocysteine level and disease development in vitiligo

Increasing evidence on the association of MTHFR gene polymorphism and serum homocysteine levels with autoimmune diseases such as vitiligo has made the MTHFR gene a very interesting candidate to be evaluated in different ethnicities and populations. We aimed to evaluate the levels of serum homocysteine and vitamin B12 and their associations with MTHFR C677T polymorphism in the Iranian population. This case-control study included 104 patients with vitiligo and 100 age- and sex-matched healthy control subjects. Serum vitamin B12 and homocysteine levels were measured by a chemiluminescence assay. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used for genotyping the polymorphism. The mean serum homocysteine levels were significantly higher in cases than controls and associated with disease activity (p < .001). Furthermore, the homozygous MTHFR C677T variant genotype was associated with vitiligo development (adjusted OR: 3.52, 95% CI: 1.09-11.32, p = .02) and elevated homocysteine level (p < .001). There was no association between serum vitamin B12 levels and the MTHFR C677T genotype. The homozygous variant MTHFR C677T may be considered as a risk factor for both elevated homocysteine levels and the development of vitiligo in the Iranian population. Although these results are not conclusive, they could elucidate the contribution of genetic and immune-mediated inflammatory factors to the pathogenesis of vitiligo.

Excessive Methionine Supplementation Exacerbates the Development of Abdominal Aortic Aneurysm in Rats

OBJECTIVE

The relationship between methionine (Met) and abdominal aortic aneurysm (AAA) has been previously demonstrated, but the mechanisms controlling this association remain unclear. This study investigated the potential contribution of hypermethioninemia (HMet) to the development of AAA.

METHODS

A model of AAA was induced by intraluminal porcine pancreatic elastase (PPE) infusion in 60 male Sprague-Dawley rats divided into 4 groups (n = 15 per group). Met was supplied by intragastric administration (1 g/kg body weight/day) from 1 week before surgery until 4 weeks after surgery. The aortic diameter was measured by ultrasound. Aortas were collected 4 weeks after surgery and subjected to biochemical analysis, histological assays, and transmission electron microscopy.

RESULTS

After 5 weeks of Met supplementation, HMet increased the dilation ratio of the HMet + PPE group, and hyperhomocysteinemia was also induced in HMet and HMet + PPE rats. Increased matrix metalloproteinase-2 (MMP-2), osteopontin, and interleukin-6 expression was detected in HMet + PPE rats. Furthermore, increased autophagy was detected in the HMet + PPE group.

CONCLUSION

This study demonstrates that HMet may exacerbate the formation of AAA due to the increased dilation ratio partially via enhancing MMP-2 and inflammatory responses.

The Role of Nitric Oxide, ADMA, and Homocysteine in The Etiopathogenesis of Preeclampsia-Review

Preeclampsia is a serious, pregnancy-specific, multi-organ disease process of compound aetiology. It affects 3–6% of expecting mothers worldwide and it persists as a leading cause of maternal and foetal morbidity and mortality. In fact, hallmark features of preeclampsia (PE) result from vessel involvement and demonstrate maternal endothelium as a target tissue. Growing evidence suggests that chronic placental hypoperfusion triggers the production and release of certain agents that are responsible for endothelial activation and injury. In this review, we will present the latest findings on the role of nitric oxide, asymmetric dimethylarginine (ADMA), and homocysteine in the etiopathogenesis of preeclampsia and their possible clinical implications.

Effect of Homocysteine on the Differentiation of CD4+ T Cells into Th17 Cells

BACKGROUND

The hyperhomocysteinaemia (Hhcy) is a common phenomenon observed in patients with inflammatory bowel disease (IBD). Our previous study showed that Hhcy aggravated intestinal inflammation in an animal model of colitis. Increased levels of IL-17 and RORγt were also observed in this animal model of colitis with Hhcy. However, the direct effect of homocysteine on the differentiation of Th17 cells has never been studied. The aim of this study was to investigate the direct effect of Hhcy on the differentiation of CD4⁺ T cells into Th17 cells.

METHOD

Lamina propria lymphocytes (LPLs) in colonic mucosa of Wistar rats were isolated and cultured under Th17-inducing (iTH17) environments. Different concentrations of the Hcy (0-100 μmol/ml) were added alone or combined with IL-23 (100 ng/ml) or folate (5 μmol/ml). The LPLs were divided into eight groups as follows: (1) Control group; (2) 10 μmol/ml Hcy group; (3) 25 μmol/ml Hcy group; (4) 50 μmol/ml Hcy group; (5) 100 μmol/ml Hcy group; (6) 100 ng/ml IL-23 group; (7) 50 μmol/ml Hcy + 100 ng/ml IL-23 group and (8) 50 μmol/ml Hcy + 100 ng/ml IL-23 + 5 μmol/ml folate group. The protein expression levels of IL-17, retinoid-related orphan nuclear receptor-γt (RORγt), p38 MAPK, phosphorylated p38 MAPK, cytosolic phospholipase A2 (cPLA2), phosphorylated-cPLA2 and cyclooxygenase 2 (COX2) were detected by immunoblot analysis. The protein level of prostaglandin E2 (PGE2) and IL-17 was detected by ELISA, and IL-17 and RORγt-positive CD4⁺ T cells were stained and analyzed by flow cytometry.

RESULTS

Hcy increased the protein levels of IL-17, RORγt, the ratio of phosphorylated p38 MAPK to p38 MAPK (p-p38/p38), the ratio of phosphorylated cPLA2 to cPLA2 (p-cPLA2/cPLA2) and COX2. The effect was concentration dependent to a certain degree; Hcy of 50 μmol/ml was the optimal concentration to increase the protein levels of those molecules. The level of IL-17 and PGE2 in the cell culture supernatants and the expression of IL-17 and RORγt in positive CD4⁺ T cells were also increased in the group of Hhcy. IL-23 showed a cooperative effect with Hcy on the differentiation of CD4⁺ Th cells into Th17 cells, whereas folate supplementation showed an inhibition action.

CONCLUSIONS

Homocysteine promoted the differentiation of CD4⁺ T cells into Th17 cells in a dose-dependant manner. This effect could be inhibited by folate.

Serum homocysteine, folate, and vitamin B12 levels in patients with vitiligo and their potential roles as disease activity biomarkers: A systematic review and meta-analysis

BACKGROUND

Hyperhomocysteinemia and folate and vitamin B₁₂ deficiencies have been reported in patients with vitiligo. Investigating the role of these conditions might shed light on the pathogenesis of vitiligo.

OBJECTIVE

To perform a systematic review and meta-analysis of studies assessing serum homocysteine, folate, and vitamin B₁₂ levels in vitiligo patients.

METHODS

Online databases were searched on May 15, 2018, to identify studies comparing serum homocysteine, folate, and vitamin B₁₂ levels between patients with vitiligo and controls. A random effects model was used.

RESULTS

Twenty-two studies involving a total of 1448 patients with vitiligo were included. Patients with vitiligo had significantly higher serum homocysteine levels (standardized mean difference [SMD] 0.550, 95% confidence interval [CI] 0.262-0.838; I² 87.3%) and lower vitamin B₁₂ levels (SMD -0.430, 95% CI -0.738 to -0.121; I² 85.3%) than controls. Serum folate levels were not significantly different between the 2 groups (SMD -0.240, 95% CI -0.592 to 0.111; I² 85.5%). A subgroup analysis revealed that these findings correlated with disease activity.

LIMITATIONS

The included studies were heterogeneous. Serum homocysteine levels could be influenced by various factors.

CONCLUSION

Patients with vitiligo have higher serum homocysteine levels and lower vitamin B₁₂ levels than individuals without vitiligo.

Glycosaminoglycan Neutralization in Coagulation Control

The glycosaminoglycans (GAGs) heparan sulfate, dermatan sulfate, and heparin are important anticoagulants that inhibit clot formation through interactions with antithrombin and heparin cofactor II. Unfractionated heparin, low-molecular-weight heparin, and heparin-derived drugs are often the main treatments used clinically to handle coagulatory disorders. A wide range of proteins have been reported to bind and neutralize these GAGs to promote clot formation. Such neutralizing proteins are involved in a variety of other physiological processes, including inflammation, transport, and signaling. It is clear that these interactions are important for the control of normal coagulation and influence the efficacy of heparin and heparin-based therapeutics. In addition to neutralization, the anticoagulant activities of GAGs may also be regulated through reduced synthesis or by degradation. In this review, we describe GAG neutralization, the proteins involved, and the molecular processes that contribute to the regulation of anticoagulant GAG activity.

The metabolism and significance of homocysteine in nutrition and health

An association between arteriosclerosis and homocysteine (Hcy) was first demonstrated in 1969. Hcy is a sulfur containing amino acid derived from the essential amino acid methionine (Met). Hyperhomocysteinemia (HHcy) was subsequently shown in several age-related pathologies such as osteoporosis, Alzheimer's disease, Parkinson's disease, stroke, and cardiovascular disease (CVD). Also, Hcy is associated with (but not limited to) cancer, aortic aneurysm, hypothyroidism and end renal stage disease to mention some. The circulating levels of Hcy can be increased by defects in enzymes of the metabolism of Met, deficiencies of vitamins B6, B12 and folate or by feeding Met enriched diets. Additionally, some of the pharmaceuticals currently in clinical practice such as lipid lowering, and anti-Parkinsonian drugs are known to elevate Hcy levels. Studies on supplementation with folate, vitamins B6 and B12 have shown reduction in Hcy levels but concomitant reduction in certain associated pathologies have not been definitive. The enormous importance of Hcy in health and disease is illustrated by its prevalence in the medical literature (e.g. > 22,000 publications). Although there are compelling data in favor of Hcy as a modifiable risk factor, the debate regarding the significance of Hcy mediated health effects is still ongoing. Despite associations between increased levels of Hcy with several pathologies being well documented, whether it is a causative factor, or an effect remains inconclusive. The present review though not exhaustive, is focused on several important aspects of Hcy metabolism and their relevance to health.

Upregulation of DAPK contributes to homocysteine-induced endothelial apoptosis via the modulation of Bcl2/Bax and activation of caspase 3

Hyperhomocysteinemia is characterized by an abnormally high level of homocysteine (Hcy) in the blood and is associated with cardiovascular diseases such as atherosclerosis. Endothelial dysfunction may lead to the pro-atherogenic effects associated with hyperhomocysteinemia. Endothelial dysfunction induced by Hcy has been previously investigated; however, the underlying molecular mechanism remains to be fully elucidated. The present study investigated whether death-associated protein kinase (DAPK) is involved in Hcy‑induced apoptosis in human umbilical vein endothelial cells (HUVECs). It was determined that Hcy treatment upregulated the mRNA and protein expression levels of DAPK in HUVECs. Additionally, it was identified that the knockdown of DAPK using small interfering RNA may attenuate the Hcy-induced apoptosis and dissipation of mitochondrial membrane potential. DAPK inhibition may also reverse the effect of Hcy by the upregulation of B cell leukemia/lymphoma 2 (Bcl2) and poly ADP‑ribose polymerase, and the downregulation of Bcl2‑associated X protein (Bax) and of caspase 3. In conclusion, the present study demonstrated that DAPK contributed to the Hcy‑induced endothelial apoptosis via modulation of Bcl2/Bax expression levels and activation of caspase 3.

The Effect of High Dose Folic Acid throughout Pregnancy on Homocysteine (Hcy) Concentration and Pre-Eclampsia: A Randomized Clinical Trial

Pre-eclampsia is a pregnancy-related multi-systemic hypertensive disorder and affects at least 5% of pregnancies. This randomized clinical trial aimed at assessing the effect of low doses and high doses of folic acid on homocysteine (Hcy) levels, blood pressure, urea, creatinine and neonatal outcome. A randomized clinical trial was done at Alzahra Teaching Hospital, Tabriz University of Medical Sciences from April 2008 to March 2013. Four-hundred and sixty nulliparous pregnant women were randomly assigned into two groups. Group 1 (n = 230) received 0.5 mg of folic acid and group 2 (n = 230) received 5 mg of folic acid per daily. They were followed until delivery. Blood pressure and laboratory changes, including plasma Hcy levels, were measured and compared between the groups. Homocysteine concentrations were significantly higher at the time of delivery in group 1 (13.17±3.89 μmol/l) than in group 2 (10.31±3.54, μmol/l) (p<0.001). No statistically significant differences were observed in systolic and diastolic blood pressure (p = 0.84 and 0.15, respectively). Birth weight was significantly higher in group 2 (p = 0.031) and early abortion was significantly higher in group 1 than group 2 (p = 0.001). This study has provided evidence that a high dosage of folic acid supplements throughout pregnancy reduces Hcy concentrations at the time of delivery.

Trial Registration: Iranian Registry of Clinical Trials IRCT201402175283N9

Homocysteine is associated with the progression of non-culprit coronary lesions in elderly acute coronary syndrome patients after percutaneous coronary intervention

BACKGROUND

The influence of homocysteine (Hcy) on the migration and proliferation of vascular smooth muscle cells has been well established. However, the impact of Hcy levels on the progression of non-culprit coronary lesions (NCCLs) is controversial. This study aims to evaluate whether the plasma level of Hcy is related to the progression of NCCLs after percutaneous coronary stent implantation in elderly patients with acute coronary syndrome (ACS).

METHODS

A total of 223 elderly patients (≥ 65 years old) with ACS undergoing stent implantation and follow-up coronary angiography were enrolled. Laboratory determination comprised of blood sample evaluation for Hcy was carried out before baseline coronary intervention. The patients were classified into two groups according to the blood Hcy tertiles (≥ 15 mmol/L or < 15 mmol/L). Patients were followed up for 12.2 months. NCCL progression was assessed by three-dimensional quantitative coronary angiography.

RESULTS

A significantly higher ratio of NCCL progression was observed in the group with baseline Hcy concentrations above 15 mmol/L compared to the group with concentrations below 15 mmol/L (41/127, 32.3% vs. 14/96, 14.6%, P = 0.002). Multivariate Cox regression analysis showed that Hcy and diabetes mellitus were independent risk factors for NCCL progression. The crude hazard ratio (HR) of NCCL progression for Hcy level was 1.056 (95% CI: 1.01-1.104, P = 0.015). The adjusted HR of NCCL progression for Hcy level was 1.024 (95% CI: 1.007-1.042, P = 0.007). The adjusted HR of NCCL progression for diabetes mellitus was 1.992 (95% CI: 1.15-3.44, P = 0.013).

CONCLUSIONS

Hcy is an independent risk factor for NCCL progression after 12 months of follow-up in elderly patients with ACS who has undergone percutaneous coronary stenting.

HSP27 Inhibits Homocysteine-Induced Endothelial Apoptosis by Modulation of ROS Production and Mitochondrial Caspase-Dependent Apoptotic Pathway

Objectives. Elevated plasma homocysteine (Hcy) could lead to endothelial dysfunction and is viewed as an independent risk factor for atherosclerosis. Heat shock protein 27 (HSP27), a small heat shock protein, is reported to exert protective effect against atherosclerosis. This study aims to investigate the protective effect of HSP27 against Hcy-induced endothelial cell apoptosis in human umbilical vein endothelial cells (HUVECs) and to determine the underlying mechanisms. Methods. Apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) of normal or HSP27-overexpressing HUVECs in the presence of Hcy were analyzed by flow cytometry. The mRNA and protein expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Results. We found that Hcy could induce cell apoptosis with corresponding decrease of nitric oxide (NO) level, increase of endothelin-1 (ET-1), intracellular adhesion molecule-1 (ICAM-1), vascular cellular adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1) levels, elevation of ROS, and dissipation of MMP. In addition, HSP27 could protect the cell against Hcy-induced apoptosis and inhibit the effect of Hcy on HUVECs. Furthermore, HSP27 could increase the ratio of Bcl-2/Bax and inhibit caspase-3 activity. Conclusions. Therefore, we concluded that HSP27 played a protective role against Hcy-induced endothelial apoptosis through modulation of ROS production and the mitochondrial caspase-dependent apoptotic pathway.

Endothelial Nitric Oxide Synthase T-786C Mutation, Prothrombin Gene Mutation (G-20210-A) and Protein S Deficiency Could Lead to Myocardial Infarction in a Very Young Male Adult

INTRODUCTION:

Myocardial infarction is a rare medical event in young people. The main reasons include congenital coronary abnormalities, coronary artery spasm, and coronary thrombosis due to hypercoagulable states (hereditary and acquired).

AIM:

We present a case of a young male adult with myocardial infarction caused by a combination of gene mutations and anticoagulation protein deficiency.

CASE PRESENTATION:

A 19 years old young man was admitted to our hospital complaining of chest pain during the last two weeks. The patient did not have any known cardiovascular risk factors, except a positive family anamnesis. Subacute inferior nonST segment myocardial infarction was diagnosed according to the patient’s history, electrocardiographic and laboratory findings. Coronary angiography revealed suboclusive thrombus in the proximal, medial and distal part of the right coronary artery (TIMI 2). Percutaneous coronary intervention was performed. Anticoagulant and antiagregant therapy (heparin, acetilsalicilic acid and clopidogrel) according to protocol was started. The hospital stay was uneventful. Homozygous endothelial nitric oxid synthase (eNOS) T-786-C mutation, heterozygote prothrombin gene mutation (G-20210-A), and protein S deficiency were verified from the thrombophilia testing. Other trombophilic tests were normal. Three months after discharge from hospital another coronary angiography was performed. It revealed normal coronary arteries. Four years after the attack, the patient is free of symptoms and another cardiovascular event.

CONCLUSION:

Combination of genetic mutations and anticoagulation protein deficiency could be a reasonable cause for myocardial infarction in a very young male adult without any other cardiovascular risk factors.

Consequence of hyperhomocysteinaemia on α1-adrenoceptor-mediated contraction in the rat corpus cavernosum: the role of reactive oxygen species

OBJECTIVES

Our main objective was to investigate the mechanisms underlying the effects of hyperhomocysteinaemia (HHcy) on contractile response mediated by α1-adrenoceptors in the rat corpus cavernosum.

METHODS

Concentration-response curves for phenylephrine (PE) were obtained in strips of corpus cavernosum, in absence or after incubation with tiron, tempol or polyethylene glycol (PEG)-catalase combined or not with tempol. We also measured the superoxide anion (O2(-)) and hydrogen peroxide (H2O2) generation, superoxide dismutase (SOD) and catalase activity and α-actin expression in rat corpus cavernosum from both groups.

KEY FINDINGS

HHcy increased PE-induced contraction in cavernosal strips. Tiron, PEG-catalase or tempol increased PE-induced contraction in strips from control rats, but it was not altered by tiron or PEG-catalase in HHcy rats, whereas tempol reduced this response. The combination of PEG-catalase and tempol did not alter the contractile response to PE in both groups. HHcy increased O2(-) generation and SOD activity, whereas H2O2 concentration was reduced. Finally, HHcy did not alter catalase activity or expression of α-actin.

CONCLUSIONS

The major new finding from this study is that HHcy induced a marked increase in PE-induced contraction in rat corpus cavernosum by a mechanism that involves increased O2(-) generation and it could play a role in the pathogenesis of erectile dysfunction associated with HHcy.

Evaluation of Serum Homocysteine, High-Sensitivity CRP, and RBC Folate in Patients with Alopecia Areata

Introduction:

Alopecia areata (AA) is a common type of hair loss with an autoimmune basis. As the role of homocysteine (Hcys), folate, and CRP has been considered in some autoimmune diseases.

Objectives:

To evaluate homocysteine, folate and CRP level in AA.

Methods:

This study was performed on 29 patients who had AA for at least 6 months affecting more than 20% of scalp, and 32 healthy controls. Levels of serum Hcys, blood high-sensitivity CRP, and RBC folate were measured in all subjects.

Results:

The mean level of RBC folate was significantly lower in the patient group than that in controls (P < 0.001). Also, the level of RBC folate was significantly lower in patients with extensive forms of disease (alopecia totalis/alopecia universalis) in comparison with more localized form (patchy hair loss) (P < 0.05). Patients with higher “Severity of Alopecia Total” (SALT) score had lower RBC folate, as well. Serum Hcys and blood high-sensitivity CRP levels did not show a significant difference in two groups.

Conclusion:

Patients with alopecia areata have lower level of RBC folate which is in negative correlation with both severity and extension of AA.

Diagnosis of cystathionine beta-synthase deficiency by genetic analysis

Intellectual disability like other common diseases is often complex because they are genetically heterogeneous, with many different genetic defects giving rise to clinically indistinguishable phenotypes. We present diagnosis of cystathionine beta-synthase (CBS) deficiency in a multiply affected Iranian family with obvious intellectual disability based on whole genome SNP homozygosity mapping. Diagnosis based on clinical presentations had not been made because of unavailability of appropriate medical services. Genetic analysis led to identification of homozygous c.346G>A in CBS that causes p.Gly116Arg in the encoded protein, cystathionine beta-synthase. CBS is the most common causative gene of homocystinurea. Later, the same mutation was found in three other apparently unrelated Iranian homocystinuria patients. p.Gly116Arg was reported once before in a Turkish patient, suggesting it may be a common CBS deficiency causing mutation in the Middle East. Clinical features of the patients are reported that evidence to variable presentations caused by the same mutation. Finally, observations in heterozygous carriers of the mutation suggest data that a single allele of the p.Gly116Arg causing mutation may have phenotypic consequences, including cardiac related phenotypes. Our study attests to the powers of genetic analysis for diagnosis especially for some forms of intellectual disability, with known genetic causing agents.

High‑dose folic acid improves endothelial function by increasing tetrahydrobiopterin and decreasing homocysteine levels

The aim of this study was to investigate the effect of folic acid (FA) on tetrahydrobiopterin (BH4), neopterin, nitric oxide (NO) and homocysteine (Hcy) levels in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were cultured in vitro in the presence or absence of Hcy. The effect of various doses of FA on Hcy, BH4, neopterin and NO concentrations in HUVECs was then assessed. In the 5 and 10 nmol/l FA treatment groups, FA was found to significantly increase the levels of BH4 (10.56±3.86 and 11.23±2.1919 pmol/g vs 6.32+2.87 nmol/g; P<0.05 vs. control) and NO production (37.86±12.34 nmol/l, 38.45±11.23 nmol/l vs 26.21±9.24 nmol/l; P<0.001 vs. paired Hcy group), but reduce the levels of Hcy (132.87±29.67 and 140.87±26.76 nmol/l vs. 165.23±30.56 nmol/l; P<0.05 vs. Hcy group). No significant differences were observed in neopterin levels among the different groups of HUVECs. In conclusion, high doses of FA may be capable of protecting endothelial cells through reducing levels of Hcy and increasing BH4 and NO production.

Mechanisms involved in attenuated cardio-protective role of ischemic preconditioning in metabolic disorders

Myocardial infarction is a pathological state which occurs due to severe abrogation of the blood supply (ischemia) to a part of heart, which can cause myocardial damage. The short intermittent cycles of sub-lethal ischemia and reperfusion has shown to improve the tolerance of the myocardium against subsequent prolonged ischemia/reperfusion (I/R)-induced injury, which is known as ischemic preconditioning (IPC). Although, IPC-induced cardioprotection is well demonstrated in various species, including human beings, accumulated evidence clearly suggests critical abrogation of the beneficial effects of IPC in diabetes mellitus, hyperlipidemia and hyperhomocysteinemia. Various factors are involved in the attenuation of the cardioprotective effect of preconditioning, such as the reduced release of calcitonin gene-related peptide (CGRP), the over-expression of glycogen synthase kinase-3β (GSK-3β) and phosphatase and tensin homolog (PTEN), impairment of mito-KATP channels, the consequent opening of mitochondrial permeability transition pore (MPTP), etc. In this review, we have critically discussed the various signaling pathways involved in abrogated preconditioning in chronic diabetes mellitus, hyperlipidemia and hyperhomocysteinemia. We have also focused on the involvement of PTEN in abrogated preconditioning and the significance of PTEN inhibitors.

Lamotrigine decreased hippocampal damage and improved vascular risk markers in a rat model of pentylenetetrazole induced kindling seizure

Various antiepileptic drugs (AEDs) especially enzyme-inducing AEDs might be associated with increased vascular risk, through impairment of the endogenous antioxidative ability which may trigger oxygen-dependent tissue injury. Lamotrigine (LTG) a non-enzyme-inducing AED has scarce information regarding its effects on oxidative stress. The present study aimed to study the possible modulation of vascular risk factors of epileptogenesis by LTG, in a rat model of kindling seizure induced by pentylenetetrazole (PTZ). Four groups of male Wister rats were used; vehicle control group, PTZ group (alternate day PTZ, 30 mg/kg, i.p), LTG/PTZ group (LTG 20 mg/kg/day p.o and alternate day PTZ) and LTG group. The study period was 5 weeks. Lipoproteins and total homocysteine (tHcy), malondialdehyde (MDA) and reduced glutathione (GSH) were measured. Aortic endothelial function study and histopathological examination of the rats' brains, aortas and coronaries were conducted. Serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), tHcy, MDA, GSH levels were significantly higher in epileptic rats than normal controls rats. A decrease in HDL-cholesterol with high atherosclerotic index was also demonstrated. The administration of LTG improved the PTZ-kindled seizures. It produced a significant decrease in TC, TG and LDL-cholesterol, MDA, aortic GSH and increase in HDL-cholesterol with no significant effect on serum GSH and tHcy levels. LTG improved endothelium-dependent relaxation, decreased hippocampal neurodegenerative changes and atherosclerotic changes of aortas and coronaries. LTG decreased seizures severity, hippocampal damage and improved vascular risk markers in this rat model of kindling seizures.

High plasma homocysteine increases risk of metabolic syndrome in 6 to 8 year old children in rural Nepal

Little attention has been given to the association of plasma homocysteine (Hcy) and metabolic syndrome (MetS) in children. We have evaluated the risk of MetS with plasma Hcy in a cohort of 6 to 8 year old rural Nepalese children, born to mothers who had participated in an antenatal micronutrient supplementation trial. We assessed Hcy in plasma from a random selection of n = 1000 children and determined the relationship of elevated Hcy (>12.0 μmol/L) to MetS (defined as the presence of any three of the following: abdominal adiposity (waist circumference ≥ 85th percentile of the study population), high plasma glucose (≥85th percentile), high systolic or diastolic blood pressure (≥90th percentile of reference population), triglyceride ≥ 1.7 mmol/L and high density lipoprotein < 0.9 mmol/L.) and its components. There was an increased risk of low high-density lipoproteins (HDL), [odds ratios (OR) = 1.77, 95% confidence intervals (CI) = 1.08–2.88; p = 0.020], high blood pressure [OR = 1.60, 95% CI = 1.10–2.46; p = 0.015] and high body mass index (BMI) [OR = 1.98, 95% CI = 1.33–2.96; p = 0.001] with elevated Hcy. We observed an increased risk of MetS (OR = 1.75, 95% CI = 1.06–2.90; p = 0.029) with elevated Hcy in age and gender-adjusted logistic regression models. High plasma Hcy is associated with increased risk of MetS and may have implications for chronic disease later in life.

[Analysis of the effect of N5, N10-methylenetetrahydrofolate reductase gene C(677)-->T polymorphism on the ischemic stroke development in persons with various risk factors]

The results ofMTHFR gene C(677)-->T (rs1801133) polymorphism determined in 170 patients with ischemic atherothrombotic stroke (IATS) and 124 healthy subjects (control group) are presented in the paper. It has been shown that in patients with IATS, the frequencies of main homozygotes (CC), heterozygotes (CT) and minor homozygotes (TT) are 52.4, 35.9, 11.8% (in control--46.0, 48.4, 5.6%, P = 0.044 by chi2-test). TT homozygotes have a greater chance of developing IATS than carriers of main C-allele (CT + CC) (OR = 2.3, CI = 0.911-5.449, P = 0.049). In the representatives of the Ukrainian population there is a relationship between the frequency of MTHFR gene C(677)-->T polymorphism genotypes and the risk of IATS. This connection is manifested in male patients, in persons with normal blood pressure, and in people who do not have the habit of smoking. The sex of the patients, body mass index, blood pressure and smoking affect the level of the studied polymorphism association with stroke.

Hydrogen sulfide chemical biology: pathophysiological roles and detection

Hydrogen sulfide (H2S) is the most recent endogenous gasotransmitter that has been reported to serve many physiological and pathological functions in different tissues. Studies over the past decade have revealed that H2S can be synthesized through numerous pathways and its bioavailability regulated through its conversion into different biochemical forms. H2S exerts its biological effects in various manners including redox regulation of protein and small molecular weight thiols, polysulfides, thiosulfate/sulfite, iron-sulfur cluster proteins, and anti-oxidant properties that affect multiple cellular and molecular responses. However, precise measurement of H2S bioavailability and its associated biochemical and pathophysiological roles remains less well understood. In this review, we discuss recent understanding of H2S chemical biology, its relationship to tissue pathophysiological responses and possible therapeutic uses.

Plasmatic higher levels of homocysteine in non-alcoholic fatty liver disease (NAFLD)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease, which includes a spectrum of hepatic pathology such as simple steatosis, steatohepatitis, fibrosis and cirrhosis. The increased serum levels of homocysteine (Hcy) may be associated with hepatic fat accumulation. Genetic mutations in the folate route may only mildly impair Hcy metabolism. The aim of this study was to investigate the relation between liver steatosis with plasma homocysteine level and MTHFR C677T and A1298C polymorphisms in Brazilian patients with NAFLD.

METHODS

Thirty-five patients diagnosed with NAFLD by liver biopsy and forty-five healthy controls neither age nor sex matched were genotyped for C677T and A1298C MTHFR polymorphisms using PCR-RFLP and PCR-ASA, respectively, and Hcy was determined by HPLC. All patients were negative for markers of Wilson's, hemochromatosis and autoimmune diseases. Their daily alcohol intake was less than 100 g/week. A set of metabolic and serum lipid markers were also measured at the time of liver biopsies.

RESULTS

The plasma Hcy level was higher in NAFLD patients compared to the control group (p = 0.0341). No statistical difference for genotypes 677C/T (p = 0.110) and 1298A/C (p = 0.343) in patients with NAFLD and control subjects was observed. The genotypes distribution was in Hardy-Weinberg equilibrium (677C/T p = 0.694 and 1298 A/C p = 0.188). The group of patients and controls showed a statistically significant difference (p < 0.001) for BMI and HOMA_IR, similarly to HDL cholesterol levels (p < 0,006), AST, ALT, γGT, AP and triglycerides levels (p < 0.001). A negative correlation was observed between levels of vitamin B12 and Hcy concentration (p = 0.005).

CONCLUSION

Our results indicate that plasma Hcy was higher in NAFLD than controls. The MTHFR C677T and A1298C polymorphisms did not differ significantly between groups, despite the 677TT homozygous frequency was higher in patients (17.14%) than in controls (677TT = 4.44%) (p > 0.05). The suggested genetic susceptibility to the MTHFR C677T and A1298C should be confirmed in large population based studies.

[Homocysteine, vitamin B-12, folic acid and the cognitive decline in the elderly]

Hyperhomocysteinemia is a risk factor for neurological diseases, but the underlying pathophysiology has not been adequately explained. Mild hyperhomocysteinemia, which is sometimes associated with a low plasma level of vitamin B9, B12 and folic acid, is responsible in the toxicity in neural cell by activating NMDA receptor. Indeed, even if vitamin supplementation has clearly proven its efficiency on lowering plasma levels of homocysteine, recent studies do not show any positive effect of vitamin therapy on cognitive function. The hypothesis that this therapy is inefficient has been recently reinforced by two randomized trials on the effects of vitamin supplementation. Several hypotheses still need to be explored: Mechanisms of homocysteine toxicity and that of total uselessness of vitamin supplementation; the possible need to complete the actual data with further, more powerful studies in order to prove the role of homocysteine in the development of neurodegenerative diseases and a clinical effect of vitamin therapy.

Increased level of serum Homocysteine in vitiligo

BACKGROUND

Vitiligo is an acquired depigmenting disorder caused by the destruction of melanocytes. The exact etiopathogenesis and mechanisms of vitiligo are not fully understood. Vitamin B12 and folic acid levels are decreased in vitiligo, which are the important cofactors required in the metabolism of Homocysteine (Hcy). Consequently, Hcy level increases in the circulation. Therefore, it is possible that increased Hcy plays a role in melanocytes destruction. The aim was to study for any association of vitiligo with serum Hcy level.

METHOD

A total of 30 vitiligo patients of both sexes and 30 control subjects were enrolled in this study. Sera from patients and controls were assayed for Hcy by Enzyme immunoassay. The collected data were analyzed by SPSS version-16.

RESULTS

The mean serum level of Hcy was significantly higher in patients with vitiligo as compared with healthy controls and its level was high in male patients as compared with female patients. The Hcy level in vegetarian patients was significantly higher as compared with nonvegetarian patients. The Hcy level was also significantly higher in active vitiligo patients as compared with stable vitiligo patients.

CONCLUSION

An increased serum Hcy may be a precipitating factor for vitiligo in the predisposed individuals. Serum Hcy is related to the gender of patients, activity of disease, and dietary habits of vitiligo patients.

[Determinants and relationship of homocysteinemia with cardiometabolic risk factors. A study in Benin, West Africa]

INTRODUCTION

Elevated circulating homocysteine (Hcy) is considered as an independent cardiovascular disease risk factor. Hyperhomocysteinaemia (HHcy) is influenced by nutritional, genetic, and environmental factors. The purpose of the study was to assess HHcy prevalence in Benin, its association with intakes of B-vitamins (B2, B6, B9, B12), alcohol intake, and socio-economic status (SES), and its links with other factors of cardio-metabolic risk.

METHODS

The cross-sectional study included 541 apparently healthy subjects, aged 25 to 65 years, from three sites: the main city, a small city and a rural area. Hcy was measured with an ELISA test kit. The HHcy cut-off was 12 μmol/L. Dietary intake was assessed with three 24-hour recalls. We used a structured questionnaire to assess alcohol consumption, demographics, and SES according to education and an amenity score as income proxy. Criteria for obesity, hypertension, dyslipidemia and hyperglycemia were primarily those of World Health Organization (WHO) and the International Diabetes Federation.

RESULTS

Mean age was 38.1 ± 10.1 years. The prevalence of HHcy was 52.2% in men and 24.7% in women. In multiple linear regression models, Hcy in men was positively associated with alcohol intake, but only alcohol in beer. In women, Hcy was negatively related to vitamin B12 intake. According to multivariate models of cardio-metabolic risk factors, HHcy was associated in women with more than twice the odds of hypertension and with high TC/HDL-c ratio. In men, Hcy was positively and independently associated with diastolic blood pressure and with LDL-cholesterol and total cholesterol in linear regression models.

DISCUSSION

The prevalence of HHcy is high in Benin, when compared with other studies, and it was as expected higher in men than in women. Elevated Hcy was associated with inadequate intake of vitamin B12 in women, whereas alcohol consumption and its negative correlation with B12 intake was also involved in men. Although HHcy was independently associated with hypertension (in women) and more adverse cholesterol profile, no inference can be made because of the cross-sectional design of the study.

Hypermethylation of estrogen receptor-alpha gene in atheromatosis patients and its correlation with homocysteine

OBJECTIVE

To investigate the aberrant DNA methylation in promoter region of estrogen receptor alpha (ERalpha) in atherosclerosis (As) and the possible involvement of homocysteine (Hcy) in its pathogenesis.

METHODS

The blood samples were collected from 54 patients with As approved by carotid colorized ultrasound examination and 28 healthy control subjects. The methylation status of CpG islands in ER-alpha gene promoter region of genome DNA was analyzed by nested-methylation-specific PCR (nMSP). tHcy was examined by fluorescent-biochemical method. Spearman rank correlation was used to analyse the relationship between the degree of methylation in ER-alpha gene and the level of tHcy. Cultured smooth muscle cells of Homo sapiens were treated by Hcy with different concentrations and different treating time, again the DNA methylation status was assayed by nMSP, and the proliferation of SMC was assayed by MTT.

RESULTS

Hypermethylation of ER-alpha gene promoter region was found in 38 cases of atherosclerosis patients, and the methylation frequency was 70.4%. While in healthy controls, just 8 of 28 samples hypermethylation was found, only 28.6% methylation frequency was detected, much lower than the one in atherosclerosis group (p<0.05). Meanwhile, the level of tHcy in atherosclerosis group was significantly higher than that in control group (p<0.05). The spearman rank correlation analysis explored an obvious correlation between the degree of methylation in ER-alpha gene and the level of tHcy (r=0.809, p<0.05), and the severity of atherosclerotic lesion was also heightened along with the increment of plasma level of tHcy. The cultured SMCs treated by Hcy resulted in de novo methylation in promoter region of ERalpha gene with a concentration and treating time-dependent manner, and a dose-dependent promoting effect on SMC proliferation. The in vivo and in vitro data coincidently showed that the Hcy could promote the hypermethylation of ERalpha gene, which may be an important mechanism for the pathogenesis of As.

CONCLUSION

Hypermethylation of CpG islands in ER-alpha gene promoter region was found in much higher frequency in atherosclerosis patients, which is positively correlated with the increased level of plasma tHcy and the severity of atherosclerotic lesion, and the in vitro experimental results further extended above clinical data that HHcy can lead to the hypermethylation of ER-alpha gene, and hence to promote the occurrence and development of As.

Is there a relationship between homocysteine and vitiligo? A pilot study

BACKGROUND

Pigmentary dilution is observed in patients with homocystinuria. Therefore, it is possible that an increase of local homocysteine (Hcy) interferes with normal melanogenesis and plays a role in the pathogenesis of vitiligo. Vitamin B12 and folic acid, levels of which are decreased in vitiligo, are important cofactors in the metabolism of Hcy. Consequently, a nutritional deficiency in either of these two vitamins will result in an increase in homocysteine in the circulation, a finding that we expect to find in vitiligo.

OBJECTIVE

To determine the level of Hcy in the blood of patients with vitiligo as a first step in revealing if it has any relationship with the pathogenesis of vitiligo and consequently if this will have an impact on the treatment of vitiligo.

METHODS

Twenty-six patients of both sexes with vitiligo (age range 20-50 years, mean 31.4 +/- 8.09) and 26 age-matched healthy controls were included in the study. After excluding factors that may affect serum Hcy levels, blood samples from patients and controls were obtained for homocysteine determination by enzyme immunoassay.

RESULTS

The mean serum level of Hcy was significantly higher in patients with vitiligo than in controls (21.61 +/- 13.28 vs. 13.1 +/- 4.88 micromol L(-1); P < 0.001). The Hcy level was significantly higher in male patients than in female patients (28.67 +/- 15.95 vs. 15.56 +/- 6.2 micromol L(-1); P < 0.001) and in male controls compared with female controls (15.07 +/- 4.61 vs. 12.05 +/- 4.82 micromol L(-1); P < 0.001). The homocysteine level was related to the activity of vitiligo and was significantly higher in patients with progressive disease than in controls (25.4 +/- 14.99 vs. 13.1 +/- 4.88 micromol L(-1); P < 0.001). No significant difference in Hcy levels was found between either untreated vitiligo patients (22.77 +/- 13.36 micromol L(-1)) or patients receiving ultraviolet therapy (20.45 +/- 13.73 micromol L(-1)) and the total patient group (21.62 +/- 13.28 micromol L(-1)).

CONCLUSION

An elevated homocysteine level may be a precipitating factor for vitiligo in predisposed individuals. In view of the biological role of vitamin B(12) and folic acid in Hcy metabolism, we present our recommendations regarding the investigation and treatment of this common disease.

[Hydrogen sulfide (H2S), an endogenous gas with odor of rotten eggs might be a cardiovascular function regulator]

A novel concept of "gasotransmitter" arrived recently. They are small molecules of endogenous gases. Hydrogene sulfide (H2S) is qualified as the third gasotransmitter beside nitric oxide (NO) and carbon monoxide (CO). The physiological functions of endogenous H2S are not well-known. The location of the H2S synthetizing enzymes as well as the detector of endogenous levels of H2S in the tissues suggests that the cardiovascular system is a source of H2S generation. This gas relaxes vascular smooth muscle both in vitro and in vivo probably by opening smooth K+ATP channels. Being a reducing agent, H2S may alter cellular redox status. It is able to produce thiyls free radicals: SH degrees and S degrees . The advances in H2S researchs may revolutionize many conventional doctrines in the cardiovascular area.

Large-conductance Ca2+-activated K+ currents blocked and impaired by homocysteine in human and rat mesenteric artery smooth muscle cells

Plenty of evidence suggests that increased blood levels of homocysteine (Hcy) are an independent risk factor for the development of vascular diseases, but the underlying mechanisms are not well understood. It is well known that the larger conductance Ca(2+)-activated K(+) channels (BK(Ca)) play an essential role in vascular function, so the present study was conducted to determine direct effects of Hcy on BK(Ca) channel properties of smooth muscle cells. Whole-cell patch-clamp recordings were made in mesenteric artery smooth muscle cells isolated from normal rat and patients to investigate effects of 5, 50 and 500 microM Hcy on BK(Ca), the main current mediating vascular responses in these cells. In human artery smooth muscle cells, maximum BK(Ca) density (measured at +60 mV) was inhibited by about 24% (n=6, P<0.05). In rat artery smooth muscle cells, maximum BK(Ca) density was decreased by approximately 27% in the presence of 50 microM Hcy (n=8, P<0.05). In addition, when rat artery smooth muscle cells was treated with 50 microM Hcy for 24 h, maximum BK(Ca) density decreased by 58% (n=5, P<0.05). These data suggest that Hcy significantly inhibited BK(Ca) currents in isolated human and rat artery smooth muscle cells. BK(Ca) reduced and impaired by elevated Hcy levels might contribute to abnormal vascular diseases.

Toxicity and efficacy of 6-thioguanine versus 6-mercaptopurine in childhood lymphoblastic leukaemia: a randomised trial

BACKGROUND

6-mercaptopurine has been a standard component of long-term continuing treatment for childhood lymphoblastic leukaemia, whereas 6-thioguanine has been mainly used for intensification courses. Since preliminary data have shown that 6-thioguanine is more effective than 6-mercaptopurine, we compared the efficacy and toxicity of the two drugs for childhood lymphoblastic leukaemia.

METHODS

Consecutive children with lymphoblastic leukaemia diagnosed in the UK and Ireland between April, 1997, and June, 2002, were randomly assigned either 6-thioguanine (750 patients) or 6-mercaptopurine (748 patients) during interim maintenance and continuing therapy. All patients received 6-thioguanine during intensification courses. We analysed event-free and overall survival on an intention-to-treat basis. We obtained toxicity data using an adverse-event reporting system, with follow-up questionnaires to seek detailed information for specific toxicities. This trial is registered with the International Standard Randomised Controlled Number 26727615 with the name ALL97.

FINDINGS

After a median follow up of 6 years, there was no difference in event-free or overall survival between the two treatment groups. Although 6-thioguanine conferred a significantly lower risk of isolated CNS relapse than did 6-mercaptopurine (odds ratio [OR] 0.53, 95% CI 0.30-0.92, p=0.02), the benefit was offset by an increased risk of death in remission (2.22, 1.20-4.14, p=0.01), mainly due to infections during continuing therapy. Additionally, 95 patients developed veno-occlusive disease of the liver. Of these, 82 were randomly assigned 6-thioguanine, representing 11% of all 6-thioguanine recipients. On long-term follow-up, about 5% of 6-thioguanine recipients have evidence of non-cirrhotic portal hypertension due to periportal liver fibrosis or nodular regenerative hyperplasia.

INTERPRETATION

Compared with 6-mercaptopurine, 6-thioguanine causes excess toxicity without an overall benefit. 6-mercaptopurine should remain the thiopurine of choice for continuing therapy of childhood lymphoblastic leukaemia.

Dietary contaminants and oxidative stress in Inuit of Nunavik

The aim of the present study was to investigate the potential deleterious effects of dietary contaminants such as polychlorinated biphenyls (PCBs) and methylmercury (MeHg) on different molecules sensitive to oxidative stress, namely, plasma oxidized low-density lipoproteins (OxLDLs), plasma homocysteine (Hcy), blood glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH). We also planned to assess the potential beneficial effects of long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) and selenium (Se) that are also present in the traditional Inuit diet. A total of 99 participants were studied. Plasma levels of PCBs, blood levels of Se and MeHg, plasma lipids (triacylglycerols, total, LDL-, and high-density lipoprotein cholesterol [LDL-C and HDL-C, respectively], apolipoprotein B-LDL), erythrocyte n-3 PUFAs, OxLDL, Hcy, blood GPx, GSH, and GR have been determined. Mean concentrations of MeHg, Se, and PCBs were respectively 10- to 14-fold, 8- to 15-fold, and 16- to 18-fold higher than reported in white population consuming little or no fish. Multivariate analyses show that variance in plasma OxLDL concentrations was predicted by LDL-C (P = .007), HDL-C (P = .005), and PCBs (P = .006). The level of LDL oxidation, represented as the ratio OxLDL/apolipoprotein B-LDL, was predicted by LDL-C (P = .0002), HDL-C (P = .002), and GSH (P = .005). Concentration of plasma Hcy was positively predicted by age (P = .02) but negatively by body mass index (P = .04) and Se (P = .005). Glutathione was predicted by the smoking status (P = .004) and the level of LDL oxidation (P = .005), whereas GR was only predicted by the smoking status (P = .0009). The variance of GPx was not predicted by any contaminant or other physiological parameter. Dietary MeHg showed no association with the examined oxidative biomarkers, whereas PCB level was a predictor of the plasma concentration of OxLDL, although this concentration remained very low. The level of GPx activity in Inuit was higher than levels previously reported to be protective in whites. Homocysteine was negatively predicted by Se, suggesting a possible beneficial effect of Se. Moreover, n-3 PUFAs were highly correlated with dietary contaminants, but had no relationships with oxidative biomarkers. This study suggests that, in adult Inuit, contaminated traditional diet seems to have no direct oxidative effects on molecules involved in oxidative stress.

Plasma total homocysteine and cardiovascular risk in patients submitted to liver transplantation

Patients submitted to orthotopic liver transplantation (OLT) show an increased rate of cardiovascular events. OLT subjects have high homocysteine (Hcy) levels, but no data are available on the association of Hcy with cardiovascular events. In a cross-sectional analysis, 230 subjects were studied at least 6 months after OLT (159 on cyclosporine, 71 on tacrolimus). Routine laboratory data and total Hcy were recorded, as well as the history of diabetes, hypertension, dyslipidemia, and overweight. Cardiovascular events occurring in a follow-up of 2-36 months were registered. OLT subjects had higher-than-normal Hcy (median 16.7 micromol/L, range 6.1-171.8) without difference between the 2 immunosuppressive agents. The prevalence of Hcy >15 micromol/L was also similar, and significantly correlated with creatinine levels. A total of 28 arterial events occurred in 25 patients during follow-up (11 in coronary arteries, 10 in peripheral arteries, and 7 in splanchnic arteries). Deep vein thromboses occurred in 2 patients, and splanchnic vein thromboses in 4 patients. Cardiovascular events were frequently associated to high Hcy and hypertension. Cox regression analysis showed that high Hcy was significantly associated with arterial events. The risk of any arterial event, coronary artery or peripheral artery event increased by nearly 10% for any increase in Hcy of 5 micromol/L. In conclusion, high Hcy may be involved in the pathogenesis of cardiovascular events in OLT patients. The usefulness of Hcy-lowering therapy remains to be verified.

Late-onset thrombocytic microangiopathy caused by cblC disease: association with a factor H mutation

BACKGROUND

cblC disease is a cause of hemolytic uremic syndrome (HUS), which has been primarily described in neonates and infants with severe renal and neurological lesions.

PATIENTS

Two sisters aged 6 and 8.5 years presented with a latent hemolytic process characterized by undetectable or low plasma haptoglobin, respectively, associated with renal failure and gross proteinuria. Renal biopsies performed in both patients found typical findings of thrombotic microangiopathy suggesting the diagnosis of HUS. Both patients were free of neurologic signs.

RESULTS

Biochemical investigations found a cobalamin processing deficiency of the cblC type. Search for additional factors susceptible to worsen endothelial damage revealed homozygosity 677C--> T mutation in the methylenetetrahydrofolate reductase gene as well as heterozygosity for a 3254T--> C mutation in factor H in the patient with the most severe clinical presentation. Long-term subcutaneous administration of hydroxocobalamin in combination with oral betaine and folic acid resulted in clinical and biological improvement in both patients.

CONCLUSION

cblC disease may be a cause of chronic HUS with delayed onset in childhood. Superimposed mutation of factor H gene might influence clinical severity.

The High Atherosclerotic Risk Among Epileptics: the Atheroprotective Role of Multivitamins

Neurologists have little concern about the high atherosclerotic risk among epileptics. Recent evidences mount that chronic epilepsy and prolonged use of antiepileptic drugs (AEDs) are associated with multiple risk factors that are critically implicated in pathobiology and dysfunction of the vessel wall through complex molecular mechanisms that promote atherogenesis. This review is concerned with three metabolic alterations, which are attributed as major risk factors for atherosclerosis among epileptics: altered metabolism of a) homocysteine (Hcy), b) lipids and lipoproteins, and c) uric acid. Most conventional AEDs reduce folic acid levels, thereby raising Hcy levels. Hyperhomosysteinemia is recently believed to induce endothelial dysfunction and promote atherosclerosis through complex oxidative and excitatory neurotoxic molecular mechanisms. However, Hcy itself is a convulsing substance with increased seizure recurrence and intractability to antiepileptic medications. AEDs can disturb lipid metabolism with resultant hypercholestrolemia and dyslipidemia, common recognized risks for atherosclerosis. Altered uric acid metabolism is common among epileptics. Uric acid has been implicated in endothelial cell damage and decreased endothelial nitric oxide bioavailability. In the presence of atherosclerotic milieu, uric acid interacts with other substrate toxicities and increased reactive oxygen species, accelerating atherosclerosis. The above information forms the rationale for future routine screening and correction of such metabolic alterations in epileptics. A convincing argument now develops that routine polyvitamin supplementation (folic acid, vitamin B12, vitamin B6, vitamin C, vitamin E, and beta-carotene) becomes increasingly important for women and men receiving AEDs at all ages. The atheroprotective effect of multivitamins is through their antioxidant and anti-inflammatory effects together with their lipid and Hcy lowering effects.

Homocysteine and reactive oxygen species in metabolic syndrome, type 2 diabetes mellitus, and atheroscleropathy: the pleiotropic effects of folate supplementation

Homocysteine has emerged as a novel independent marker of risk for the development of cardiovascular disease over the past three decades. Additionally, there is a graded mortality risk associated with an elevated fasting plasma total homocysteine (tHcy). Metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) are now considered to be a strong coronary heart disease (CHD) risk enhancer and a CHD risk equivalent respectively. Hyperhomocysteinemia (HHcy) in patients with MS and T2DM would be expected to share a similar prevalence to the general population of five to seven percent and of even greater importance is: Declining glomerular filtration and overt diabetic nephropathy is a major determinant of tHcy elevation in MS and T2DM.

There are multiple metabolic toxicities resulting in an excess of reactive oxygen species associated with MS, T2DM, and the accelerated atherosclerosis (atheroscleropathy). HHcy is associated with an increased risk of cardiovascular disease, and its individual role and how it interacts with the other multiple toxicities are presented.

The water-soluble B vitamins (especially folate and cobalamin-vitamin B₁₂) have been shown to lower HHcy. The absence of the cystathionine beta synthase enzyme in human vascular cells contributes to the importance of a dual role of folic acid in lowering tHcy through remethylation, as well as, its action of being an electron and hydrogen donor to the essential cofactor tetrahydrobiopterin. This folate shuttle facilitates the important recoupling of the uncoupled endothelial nitric oxide synthase enzyme reaction and may restore the synthesis of the omnipotent endothelial nitric oxide to the vasculature.

Effects of homocysteine on apoptosis-related proteins and anti-oxidant systems in isolated human lymphocytes

Homocysteine (Hcy) is a nonprotein-forming sulphur amino acid that plays an important role in remethylation and trans-sulphuration processes. In recent years, it has been suggested that increased levels of plasma Hcy may play a role in the pathogenesis of various diseases, particularly at the cardiovascular level. The pathogenic mechanism of hyperhomocysteinemia, however, has not been clarified. Because oxygen radicals can be generated by the auto-oxidation of this amino acid, it has been suggested that Hcy may cause cellular damage through oxidative mechanisms, ultimately leading to apoptotic cell death. In this study, we sought to investigate the effects of Hcy on oxidative damage and antioxidant agent levels, as well as on apoptosis-related proteins and apoptosis occurrence in human cells. For this purpose, we measured levels of Bcl-2, caspase-3 and caspase-9 activity, Cu/Zn superoxide dismutase, reduced glutathione, lipid peroxidation [malondialdehyde and 4-hydroxy-2 (E)-nonenal concentrations], apoptotic single-stranded DNA and nuclear changes in human isolated lymphocytes exposed to increasing concentrations of Hcy. Incubation with Hcy did not induce significant changes in any of these biomarkers. Therefore, our results do not support the existence of a direct link between increased levels of Hcy and the occurrence of a pro-apoptotic state mediated by enhanced oxidative stress.