Public health significance of elevated homocysteine

Vitamin B12 and gestational diabetes mellitus: a systematic review and meta-analysis

The relationship between vitamin B12 and gestational diabetes mellitus (GDM) remains controversial. To comprehensively evaluate the relationship between vitamin B12 and GDM, and to provide more information on GDM prevention, this study provides a systematic review and meta-analysis of vitamin B12 and GDM. As of September 22, 2021, 304 articles were searched in PubMed, Web of Science, EMBASE, and Cochrane databases, of which 15 studies met the inclusion criteria. Results presented there was no association between maternal vitamin B12 concentration during the first trimester with GDM, however, low vitamin B12 concentration in the second or third trimester of pregnancy was related to an increased risk of GDM. Compared with the non-GDM group, the vitamin B12 concentration in the GDM group was remarkably decreased (MD: -10·79; 95%CI: -21·37, -0·21), and vitamin B12 deficiency increased the risk for GDM (OR: 1·59; 95%CI: 1·10, 2·29). These effects were more significant among Asians. In addition, an increased ratio of high folate to low vitamin B12 in serum also increased the risk of GDM (OR: 1·87; 95% CI: 1·46, 2·41). These results suggest that more vitamin B12 may need to be provided during pregnancy.

Effect of long-term chronic hyperhomocysteinemia on retinal structure and function in the cystathionine-β-synthase mutant mouse

Elevated levels of the excitatory amino acid homocysteine (Hcy) have been implicated in retinal diseases in humans including glaucoma and macular degeneration. It is not clear whether elevated Hcy levels are pathogenic. Models of hyperhomocysteinemia (Hhcy) have proven useful in addressing this including mice with deficiency in the enzyme cystathionine β-synthase (CBS). Cbs^+/- mice have a ∼two-fold increase in plasma and retinal Hcy levels. Previous studies of visual function and structure in Cbs^+/- mice during the first 10 months of life revealed mild ganglion cell loss, but minimal electrophysiological alterations. It is not clear whether extended, chronic exposure to moderate Hhcy elevation will lead to visual function loss and retinal pathology. The present study addressed this by performing comprehensive analyses of retinal function/structure in 20 month Cbs^+/- and Cbs^+/+ (WT) mice including IOP, SD-OCT, scotopic and photopic ERG, pattern ERG (pERG), and visual acuity. Eyes were harvested for histology and immunohistochemical analysis of Brn3a (ganglion cells), dihydroethidium (oxidative stress) and GFAP (gliosis). The analyses revealed no difference in IOP between groups for age/strain. Visual acuity measured ∼0.36c/d for mice at 20 months in Cbs^+/- and WT mice; contrast sensitivity did not differ between groups at either age. Similarly SD-OCT, scotopic/photopic ERG and pERG revealed no differences between 20 month Cbs^+/- and WT mice. There was minimal disruption in retinal structure when eyes were examined histologically. Morphometric analysis revealed no significant differences in retinal layers. Immunohistochemistry revealed ∼5 RGCs/100 μm retinal length in both Cbs^+/- and WT mice at 20 months. While there was greater oxidative stress and gliosis in older (20 month) mice versus young (4 month) mice, there was no difference in these parameters between the 20 month Cbs^+/- and WT mice. We conclude that chronic, moderate Hhcy (at least due to deficiency of Cbs) is not accompanied by retinal structural/functional changes that differ significantly from age-matched WT littermates. Despite considerable evidence that severe Hhcy is toxic to retina, moderate Hhcy appears tolerated by retina suggesting compensatory cellular survival mechanisms.

The Relationship Between Folate, Vitamin B12 and Gestational Diabetes Mellitus With Proposed Mechanisms and Foetal Implications

The incidence of gestational diabetes mellitus (GDM) is rising, which warrants attention due to the associated complications during pregnancy and in the long term for both mother and offspring. Studies have suggested a relationship between maternal folate (vitamin B9) and vitamin B12 status and GDM risk. Seemingly the most problematic scenario occurs when there is B-vitamin imbalance, with high folate and low vitamin B12. This nutritional state can occur in vitamin B12 deficient women who exceed the recommended folic acid supplementation. However, the pathological mechanisms behind this relationship are currently unclear and are explored in this review article. A high folate/low B12 can lead to a functional folate deficiency through the methyl-trap phenomenon, impairing re-methylation of homocysteine and regeneration of folates for DNA synthesis and repair. Consequently elevated homocysteine concentration leads to endothelial dysfunction and oxidative stress. Vitamin B12 deficiency also leads to an impairment of the conversion of methylmalonyl-CoA to succinyl-CoA, which has been associated with insulin resistance. Insulin resistance is thought to contribute to the etiology of GDM. More studies are needed to confirm the impact of these and other mechanisms on disease development. However, it highlights a potential avenue for GDM risk modification through a vitamin B12 supplement and improvement of maternal metabolic health.

A comprehensive study of the genotoxic and anti-genotoxic effects of homocysteine in HUVECs and mouse bone marrow cells

Elevated Homocysteine (Hcy) is associated with increased risk of vascular disease, but whether it induces genotoxicity to vascular endothelial cells remains unknown. Here, we conducted a comprehensive study of the genotoxicity, and unexpected anti-genotoxicity, of Hcy by cytokinesis-blocked micronucleus assay in HUVECs and erythrocyte micronucleus test in mouse bone marrow cells. Our experiments led to several important findings. First, while supraphysiological Hcy (SP-Hcy) exhibited remarkable genotoxicity, physiologically-relevant Hcy (PR-Hcy) reduced the basal genotoxicity. Second, among the metabolites of Hcy, cysteine phenocopied the anti-genotoxicity of PR-Hcy and, methionine, S-adenosylhomocysteine and H₂S phenocopied the genotoxicity of SP-Hcy. Third, the genotoxicity of SP-Hcy was mitigated by vitamin B₆, Fe²⁺ and Cu²⁺, but was exacerbated by N-acetylcysteine. Fourth, under pre-, co- or post-treatment protocol, both SP-Hcy and PR-Hcy attenuated the genotoxicity of cisplatin, mitomycin-C, nocodazole or deoxycholate. Finally, 100 and 250 mg/kg Hcy ameliorated cisplatin-induced genotoxicity in bone marrow cells of CF-1 and Kunming mice. Our results suggest that genotoxicity may be one mechanism through which Hcy confers an increased risk for vascular disease, but more importantly, they challenge the long-standing paradigm that Hcy is always harmful to human health. Our study calls for a more systematic effort in understanding the molecular mechanisms underlying the anti-genotoxicity of Hcy.

Using data mining technology to explore homocysteine at low levels

A high homocysteine level is known to be an independent risk factor for cardiovascular diseases; however, whether or not low homocysteine level contributes to any damage to the body has not been extensively studied. Furthermore, acquiring healthy subject databases from domestic studies on homocysteine is not trivial. Therefore, we aimed to investigate the causality between serum homocysteine levels and health status and lifestyle factors, particularly with a focus on low serum homocysteine levels. Additionally, we discussed a systematic methodical platform for data collection and statistical analysis, using the descriptive analysis of the chi-square test, t test, multivariate analysis of variance, and logistic regression.This study was a cross-sectional analysis of 5864 subjects (i.e., clients of a health examination clinic) in Taipei, Taiwan during a general health check-up in 2017. The patients' personal information and associated links were excluded. A sample group was selected as per the health criteria defined for this research whose data were processed using SPSS for descriptive statistical analysis using chi-square test, t test, multivariate analysis of variance, and logistic regression analysis.Those working for >12 hours/day had a higher homocysteine level than those working for <12 hours/day (P < .001). The average serum homocysteine level was 7.9 and 8.6 mol/L for people with poor sleep quality and good sleep quality, respectively (P = .003). The homocysteine value of people known to have cancer was analyzed using the logistic regression analysis, revealing a Δodds value of 0.898. The percentage of subjects with a homocysteine value of ≤6.3 μmol/L, who perceived their health status as "not very good" or "very bad," was higher than those with a higher homocysteine level. The number of subjects who perceived their health as poor was higher than expected.The results suggest that the homocysteine level could be an effective health management indicator. We conclude that normal homocysteine level should not be ≤6.3 μmol/L. Moreover, homocysteine should not be considered as harmful and its fluctuations from the normal range could be utilized to infer a person's physical status for health management.

Prevalence of hyperhomocysteinaemia, selected determinants and relation to hypertension severity in Northern-Nigerian hypertensives: the ABU homocysteine survey

Background

This study aimed at evaluating the prevalence of hyperhomocysteinaemia in Northern-Nigerian hypertensives and its association with hypertension severity and some major determinants as data regarding these are lacking in sub-Saharan Africa.

Method

A Community-based cross-sectional study done on 120 randomly-selected hypertensive patients who responded to an ABU radio frequency modulated invitation for free health-screening at the Ahmadu Bello University (ABU) Medical Centre from January 2016 to June 2016. The percentage of participants with high homocysteine levels, their anthropometric parameters and blood pressures were determined. Plasma homocysteine (hcy) was classified as normal (5–15), moderate (>15–30), intermediate (31–100) and severe (>100) µmol/L. Kruskal-Wallis test was applied and log-transformed homocysteine (Ln₁₀Homocysteine) was correlated with systolic and diastolic blood pressures as well as age, body mass index, fasting blood glucose, glomerular filtration rate, hypertension duration and Ln₁₀folate in males and females using the Pearson's Correlation analysis.

Results

There were 83(69.2%) females and 37(30.8%) males with Median homocysteine of 20.8 µmol/L and 22.0 µmol/L respectively (p=0.003). Hyperhomocysteinaemia was found in 118(98.3%) hypertensives while 2(1.7%) subjects had normo-homocysteinaemia. Moderate hyperhomocysteinaemia (Median, 20.8 µmol/L) was identified in 105(87.5%) and intermediate (Median, 40 µmol/L) in 13(10.8%) (p<0.001). No subject had severe hyperhomocysteinaemia. Homocysteine was higher (p=0.003) in subjects with Stage 2 systolic hypertension. Ln₁₀Homocysteine was significantly (p<0.001) correlated with blood pressure (SBP: r=0.45; DBP: r=0.40) and age (r=0.33).

Conclusion

The prevalence of hyperhomocysteinaemia in North-Western Nigerian hypertensives is high as against normal healthy controls. Plasma homocysteine is higher with severe systolic hypertension and positively associated with age.

Funding

No specific grants but Micro Nova Pharmaceuticals Limited, Nigeria and Emzor Pharmaceutical Industries, Lagos, Nigeria supported with drugs.

Association between methionine cycle metabolite-related diets and mild cognitive impairment in older Chinese adults: a population-based observational study

BACKGROUND

Homocysteine (Hcy) and folate, involved in a common metabolic pathway supplying essential methyl groups for DNA and protein synthesis, have been found to be associated with cognitive function. Moreover, diet may influence methionine cycle metabolites (MCM) as well as mild cognitive impairment (MCI), but MCM-related dietary patterns are unclear in an older population.

OBJECTIVE

The study aimed to identify MCM-related dietary patterns of older Chinese adults, and examine their association with the prevalence of MCI in a large population-based study.

METHODS

This study included 4457 participants ≥ 60 years of age from the Tianjin Elderly Nutrition and Cognition Cohort study. Dietary data were collected using a valid self-administered food frequency questionnaire, and factor analysis was used to identify major dietary patterns in the population. MCM-based dietary patterns were derived using reduced rank regression (RRR) based on serum folate and Hcy as response variables.

RESULTS

Compared with the participants in the lowest quartile of vegetarian pattern and processed foods pattern, the odds ratios (ORs) of MCI in the highest quartile were 0.72 (95% CI 0.53-0.98) and 1.39 (95% CI 1.03-1.88), respectively. In the MCM-based dietary patterns derived using RRR, the ORs for MCI for the highest quartile of MCM patterns I and II were 0.58 (95% CI 0.44-0.78) and 1.38 (95% CI 1.04-1.83), respectively, compared with participants in the lower quartile.

CONCLUSIONS

Findings from this large population-based study suggested that adopting an MCM-related dietary pattern, especially avoiding processed foods, can decrease the occurrence of MCI.

The Link between Exercise and Homocysteine in the Alzheimer's Disease: A Bioinformatic Network Model

Elevated peripheral expression of homocysteine (Hcy) is associated with an increased risk of coronary heart disease and stroke, diabetes, and cancer. It is also associated with cognitive impairment as it has been reported that high levels of Hcy cause cognitive dysfunction and memory deficit. Among several etiological factors that contribute to the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Hcy seems to directly contribute to the generation of neurotoxicity factors. This study aims to hypothesize the molecular mechanism by which exercise can reduce the risk of neurological complications promoted by hyperhomocysteinemia (HHcy), and discuss how exercise could reduce the risk of developing AD by using bioinformatics network models. According to the genes network, there are connections between proteins and amino acids associated with Hcy, exercise, and AD. Studies have evidenced that exercise may be one of several processes by which acid nitric availability can be maximized in the human body, which is particularly important in reducing cell loss and tau pathology and, thereby, leading to a reduced risk of complications associated with HHcy and AD.

Biochemical and Hematological Correlates of Elevated Homocysteine in National Surveys and a Longitudinal Study of Urban Adults

Elevated blood homocysteine (Hcy) among middle-aged adults can increase age-related disease risk, possibly through other biochemical and hematological markers. We selected markers for hyperhomocysteinemia among middle-aged adults, studied time-dependent Hcy-marker associations and computed highly predictive indices of hyperhomocysteinemia, with cross-sectional and longitudinal validations. We used data from the National Health and Nutrition Examination Survey (NHANES III, phase 2, n_max = 4000), the NHANES 1999–2006 (n_max = 10,151) and pooled NHANES (cross-sectional validation). Longitudinal validation consisted of mixed-effects linear regression models (Hcy predicting markers’ annual rates of change), applied to the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS, n = 227–244 participants, k = 2.4 repeats/participant, Age_base: 30–65 years) data. Machine learning detected nine independent markers for Hcy > 14 µmol/L (NHANES III, phase 2): older age; lower folate and B-12 status; higher serum levels of creatinine, uric acid, alkaline phosphatase, and cotinine; mean cell hemoglobin and red cell distribution widths (RDW); results replicated in the 1999–2006 NHANES [AUC = 0.60–0.80]. Indices combining binary markers increased elevated Hcy odds by 6.9–7.5-fold. In HANDLS, first-visit Hcy predicted annual increase in creatinine, RDW and alkaline phosphatase, with third-visit index (2013–2018) directly predicting Hcy (2004–2009). We provide evidence of the internal and external validity of indices composed of several biomarkers that are strongly associated with elevated Hcy.

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.

Regulation of Alzheimer's disease-associated proteins during epileptogenesis

Clinical evidence and pathological studies suggest a bidirectional link between temporal lobe epilepsy and Alzheimer's disease (AD). Data analysis from omic studies offers an excellent opportunity to identify the overlap in molecular alterations between the two pathologies. We have subjected proteomic data sets from a rat model of epileptogenesis to a bioinformatics analysis focused on proteins functionally linked with AD. The data sets have been obtained for hippocampus (HC) and parahippocampal cortex samples collected during the course of epileptogenesis. Our study confirmed a relevant dysregulation of proteins linked with Alzheimer pathogenesis. When comparing the two brain areas, a more prominent regulation was evident in parahippocampal cortex samples as compared to the HC. Dysregulated protein groups comprised those affecting mitochondrial function and calcium homeostasis. Differentially expressed mitochondrial proteins included proteins of the mitochondrial complexes I, III, IV, and V as well as of the accessory subunit of complex I. The analysis also revealed a regulation of the microtubule associated protein Tau in parahippocampal cortex tissue during the latency phase. This was further confirmed by immunohistochemistry. Moreover, we demonstrated a complex epileptogenesis-associated dysregulation of proteins involved in amyloid β processing and its regulation. Among others, the amyloid precursor protein and the α-secretase alpha disintegrin metalloproteinase 17 were included. Our analysis revealed a relevant regulation of key proteins known to be associated with AD pathogenesis. The analysis provides a comprehensive overview of shared molecular alterations characterizing epilepsy development and manifestation as well as AD development and progression.

Assessment of serum vitamin B12levels and chronic haemato-toxicologic adverse profile induced by metformin pharmacotherapy among type 2 diabetic patients: A prospective analytical study

Background:

The potential effect of chronic metformin pharmacotherapy to cause vitamin B12deficiency has been of tremendous concern especially among diabetic patients. Haematological abnormalities following vitamin B12deficiency among diabetic patients contribute immensely to morbidity and mortality in this group of patients.

Aim:

This study was designed to elucidate the chronic haemato-toxicologic adverse profile for metformin with respect to its potential to induce vitamin B12deficiency via reduction in the gastrointestinal absorption of vitamin B12by performing comparative analyses between the serum vitamin B12levels and haematological indices among metformin-treated and metformin-naive type 2 diabetes mellitus (DM) patients attending the outpatient Endocrinology Clinic of Irrua Specialist Teaching Hospital (ISTH), Irrua, Edo State, Nigeria, with the rational purpose of alleviating the associated morbidity and mortality.

Materials and Methods:

This was a case–control, prospective, analytical, and observational study of 200 adult participants (100 per group) attending the Endocrinology Outpatients Clinic of ISTH. Serum vitamin B12levels were analysed using an immunoassay technique. Haematological indices were determined using standard methods, and patients examined for clinical features of anaemia. Data were presented using tables and charts. χ2and t-tests were used to compare discrete and continuous data, respectively. The receiver operating characteristic (ROC) curve was plotted graphically to determine the sensitivity and specificity of using serum vitamin B12assay as a screening and diagnostic test for the haematologic abnormality of ovalocytosis among the metformin-treated type 2 DM patients.

Results:

A total of 200 type 2 diabetic patients comprising 100 metformin-treated and 100 metformin-naive patients with average age of 55.8 ± 9.3 years were studied. The mean serum vitamin B12levels in metformin-treated and metformin-naive participants with frank vitamin B12deficiency (i.e. mean serum vitamin B12level ≤ 199 pg ml−1) were 158.29 ± 29.27 pg ml−1and 173.95 ± 14.21 pg ml−1, respectively ( p = 0.028). This was significantly lower for the metformin-treated group compared to metformin-naive group with respect to the participants with frank vitamin B12deficiency. There were instances of statistically significant differences between the mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and total white blood cell (WBC) count among the metformin-treated compared to the metformin-naive type 2 DM patients. The ROC curve showed that serum vitamin B12assay had moderate sensitivity of 72% with moderate specificity of 66% at detecting the presence and absence of ovalocytosis in the presence and absence of frank vitamin B12deficiency, respectively, among the metformin-treated group (i.e. serum vitamin B12≤ 199 pg ml−1with p = 0.002).

Conclusion:

The occurrence of vitamin B12deficiency was high among metformin-treated type 2 DM patients. Our study showed remarkable statistically and clinically significant differences in the chronic haemato-toxicology of metformin on mean serum vitamin B12level, ovalocytosis, MCV, MCH and total WBC count between the metformin-treated and metformin-naive participants. We advocate for vitamin B12supplements in this group of patients via the parenteral route of administration, most preferably the intramuscular site injection; in order to prevent the occurrence of vitamin B12deficiency among them. Lastly, we recommend the use of serum vitamin B12assay and complete blood count (CBC) with peripheral blood films (PBFs) as a reliable way to diagnose and screen for vitamin B12deficiency among metformin-treated type 2 DM patients.

Hyperhomocysteinemia and folate levels in normal healthy Nigerians living in Zaria: Subanalysis of ABU homocysteine cross-sectional survey

Background

This study aimed to determine the prevalence of hyperhomocysteinemia and folate status in a sample of normal healthy Nigerians living in Zaria as well as assess the relationship between homocysteine, folate, and blood pressure (BP) levels.

Methods

It was a cross-sectional analytical study carried out among 65 normal healthy volunteers aged 18-65 years. Participants were randomly selected from willing patient escorts, hospital employees, and willing staff presenting at the Ahmadu Bello University Medical Centre, Zaria and Ahmadu Bello University Teaching Hospital, Zaria, Nigeria. The percentage of participants who had high homocysteine levels as well as their plasma folate status was determined.

Results

There were 9.2% with hyperhomocysteinemia >15 μmol/L and 51% with hyperhomocysteinemia >10 μmol/L. The mean plasma homocysteine level was 10.8 ± 2.7 μmol/L with male and female values of 10.7 ± 2.6 and 10.8 ± 2.8, respectively (P = 0.87). The mean plasma folate level was high (116.7 ± 44.0 ng/mL) with male value of (111.5 ± 44.9 ng/mL) which did not differ significantly (P = 0.37) from that of females (121.4 ± 43.3 ng/mL). Homocysteine showed a positive significant (P = 0.01) relationship with folate but not with BP's (P > 0.05).

Conclusion

There is a high prevalence of hyperhomocysteinemia in normal healthy Northern-Nigerians which cannot be accounted for by suboptimal folate levels. Hyperhomocysteinemia may not be a risk factor for cardiovascular disease in normal healthy Nigerians despite its high levels as it showed no significant relationship with BP.

Hypercysteinemia, A Potential Risk Factor for Central Obesity and Related Disorders in Azores, Portugal

In Azores, the standardized mortality rate for coronary artery disease (CAD) is nearly the double when compared to mainland Portugal. The aim of this study was to compare the prevalence of conventional CAD risk factors, as well as the plasma aminothiol profile (and its major determinants), between two groups of healthy subjects from Ponta Delgada (in Azores) and Lisbon (in mainland) cities, searching for precocious biomarker(s) of the disease. The study groups consisted of 101 healthy volunteers from Ponta Delgada (PDL) and 121 from Lisbon, aged 20–69 years. No differences in the prevalence of classical CAD risk factors were found between the study groups, except in physical inactivity and related central obesity, which were both higher in PDL men than in those from Lisbon. Hypercysteinemia, which seems to result from sulfur-rich amino acid diets and/or vitamin B₁₂ malabsorption, revealed to be significantly more prevalent in PDL vs. Lisbon subjects (18% vs. 4%, P=0.001), namely, in male gender. Moreover, plasma Cys levels predicted waist circumference (β coefficient = 0.102, P=0.032) and concomitant central obesity and were also associated with insulin resistance. Nevertheless, hyperhomocysteinemia prevalence was similar in both groups, despite the fact that PDL subjects exhibited a higher rate of vitamin B₁₂ deficiency compared to those from Lisbon (19% vs. 6%, P=0.003). Owing to the nature of this study design, a cause-effect relationship between high plasma Cys levels and central obesity or CAD risk could not be derived, but results strongly suggest that hypercysteinemia is a potential risk factor for metabolic disorders, i.e., obesity and insulin resistance, and CAD in Azores, a hypothesis that asks for confirmation through further large prospective studies.

Prevalence of vitamin B12 deficiency among metformin-treated type 2 diabetic patients in a tertiary institution, South-South Nigeria

BACKGROUND

The risk of chronic metformin pharmacotherapy to cause vitamin B12 deficiency and its associated medical complications has been of immense concern among diabetic patients. Some studies have postulated that vitamin B12 deficiency is highly prevalent among chronic metformin-treated adult diabetic patients.

AIM

This study aimed to determine the prevalence of vitamin B12 deficiency among metformin-treated and metformin-naïve type 2 diabetes mellitus patients.

MATERIALS AND METHODS

This was a case-control, prospective, analytical, observational study of 200 adult participants (100 per group) attending the Endocrinology, Medical Out-patients Clinic of Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria. The participants' serum vitamin B12 levels were determined using an immunoassay technique. Data were presented using tables and charts. Chi-square test was used to compare non-continuous proportional variables.

RESULTS

The prevalence of vitamin B12 deficiency was 41% and 20% among metformin-treated and metformin-naïve type 2 diabetes mellitus groups, respectively (p = 0.001). Borderline vitamin B12 status was present among 59% of metformin-treated group and 80% of metformin-naïve group (p = 0.001). Neither metformin-treated nor metformin-naïve groups had normal serum vitamin B12 levels.

CONCLUSION

The prevalence of vitamin B12 deficiency was significantly high in diabetics, especially the metformin-treated patients. We advocate for vitamin B12 supplementation among this group of patients in order to prevent the occurrence of vitamin B12 deficiency complications such as macro-ovalocytic anemia, impaired immunity with hypersegmented neutrophils, peripheral neuropathy and subacute degeneration of the spinal cord.

Exposure to homocysteine leads to cell cycle damage and reactive gliosis in the developing brain

Studies that investigate the cellular effects of homocysteine (Hcy) on the differentiation of neural cells, and their involvement in establishment of cell layers in the developing brain are scarce. This study evaluated how Hcy affects the neural cell cycle and proteins involved in neuronal differentiation in the telencephalon and mesencephalon using the chicken embryo as a model. Embryos at embryonic day 2 (E2) received 20 μmol D-L Hcy/50 μl saline and analyzed at E6. The Hcy treatment induced an increase in the ventricular length of the telencephalon and also a reduction of the mantle layer thickness. We observed that Hcy induced impairments to the neural cell cycle and differentiation, which compromised the cell layers establishment in the developing brain. Hcy treatment also induced changes in gene and protein expression of astrocytes, characteristic of reactive gliosis. Our results point to new perspectives of evaluation of cellular targets of Hcy toxicity.

Low Maternal Dietary Folate Alters Retrotranspose by Methylation Regulation in Intrauterine Growth Retardation (IUGR) Fetuses in a Mouse Model

Background

Maternal folate deficiency-mediated metabolic disruption is considered to be associated with the risk of intrauterine growth retardation (IUGR), but the exact mechanism remains unclear. The retrotransposon long interspersed nucleotide element-1 (LINE-1), which can induce birth defects via RNA intermediates, plays crucial roles during embryonic development. We investigated potential relationships between maternal folate and DNA methylation, and possible roles of LINE-1 in IUGR.

Material/Methods

The IUGR model was established by feeding female mice 1 of 3 diets – control diet (CD), folate-deficient diet for 2 weeks (FD2w), and folate-deficient diet for 4 weeks (FD4w) – prior to mating. Maternal serum folate, 5-methyltetrahydrofolate (5-MeTHF), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) concentrations and global DNA methylation were assessed by LC/MS/MS method. LINE-1 methylation levels in fetuses were examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. LINE-1 expression levels were validated by real-time PCR.

Results

Maternal folate deficiency caused plasma folate and 5-MeTHF levels to decrease and SAH level to increase in the FD4w group. Compared with the CD group, methylation levels of genomic DNA and LINE-1 decreased significantly in placenta and fetal tissues from the FD4w group. Expression of LINE-1 open reading frame 1 (ORF1) protein was elevated in fetal liver tissues. Furthermore, a strong correlation was found between methylation and disrupted one-carbon metabolism, implying that dietary folate plays important roles during embryogenesis.

Conclusions

Maternal dietary folate deficiency impaired one-carbon metabolism, leading to global DNA and LINE-1 hypomethylation, and then increased retrotransposition in fetuses, which can lead to IUGR.

Measurement of melatonin, indole-dioxygenase, IL-6, IL-18, ferritin, CRP, and total homocysteine levels during herpes zoster

The risk of herpes zoster (HZ) increases with age and declining immune function. Increased oxidative stress and inflammatory conditions may cause a negative impact on the immune responses. The present study aimed to assess the levels of oxidative/inflammatory stress biomarkers in HZ patients compared with the controls. This case-control study included 43 HZ patients and 47 age-matched controls. Melatonin (MLT), Indole-dioxygenase (IDO), Interleukin-18 (IL-18), Interleukin-6 (IL-6), ferritin, C-reactive protein (hsCRP), and total homocysteine (tHcy) levels were measured and compared in both groups. The significant high levels of IDO, IL-18, IL-6, ferritin, hsCRP, and tHcy, as well as low levels of MLT were found in HZ patients compared with the controls (P < 0.001); these significant differences were also associated with rash and pain severity (P < 0.001). The final logistic regression model with the area under the curve (0.99; 95% confidence interval [CI], 0.98-1.00) showed the association of HZ with decreased level of MLT (odds ratio [OR], 0.95; 95% CI, 0.92-0.98; P = 0.007) and increased levels of tHcy (OR, 1.53; 95% CI, 1.06-2.19; P = 0.02). The findings showed increased inflammation-associated oxidative stress in HZ patients. Elevated tHcy levels and reduced MLT levels may be associated with the manifestation of HZ. More investigations are required to confirm the results.

Moderately elevated preconception fasting plasma total homocysteine is a risk factor for psychological problems in childhood

OBJECTIVE

We investigated the effect of maternal preconception fasting plasma total homocysteine (tHcy) on psychological problems in children aged 6 years from normal pregnancies.

DESIGN

A longitudinal study was carried out from preconception, throughout each trimester of pregnancy, until 6 years of age in the offspring. Fasting blood samples at 2-10 weeks preconception and non-fasting samples at birth were collected. Parents completed the Child Behaviour Checklist (CBCL) and teachers the Inattention-Overactivity with Aggression (IOWA) scale for the 6-year-old children.

SETTING

Elevated tHcy during pregnancy has been associated with several adverse outcomes and with neurodevelopmental impairment in the offspring.ParticipantsThe initial sample consisted of 139 healthy non-pregnant women who were planning on becoming pregnant. Eighty-one mother-child dyads were followed from preconception until 6 years of age.

RESULTS

After adjusting for covariables, multiple linear regression models showed that higher preconception tHcy was associated with higher scores in internalizing dimension (β=0·289; P=0.028), specifically in withdrawn behaviour (β=0·349; P=0·009), anxiety/depression (β=0·303; P=0·019) and social problems (β=0·372; P=0·009). Aggressive behaviour in the school setting was higher in children whose mothers had higher preconception tHcy (β=0·351; P=0·014).

CONCLUSIONS

Moderately elevated preconception tHcy may increase the risk of psychological problems in offspring during childhood. These findings add to the evidence that maternal nutritional status, even before being pregnant, can affect later offspring health and may be important to consider when developing future public health policy.

A dietary pattern derived using B-vitamins and its relationship with vascular markers over the life course

Background

Diet may influence vascular function through elevated homocysteine (Hcy) concentrations. However the relationship between dietary patterns (DP), characterised by Hcy and its associated nutrients is unknown.

Objective

To identify a DP characterised by plasma Hcy, dietary folate and dietary vitamin B12, and examine its associations with two markers of vascular function: carotid intima-media thickness (cIMT) and pulse wave velocity (PWV).

Methods

1562 participants of the MRC National Survey of Health and Development (NSHD), a British birth cohort, with dietary data measured at least once between 36 and 60–64 years, and cIMT or PWV measured at 60–64 years were included. DPs were derived using reduced rank regression with three intermediate variables: 1) plasma Hcy (μmol/L) 2) folate intake (μg/1000 kcal) 3) vitamin B12 intake (μg/1000 kcal). Multiple regression models assessed associations between the derived DP z-scores and vascular function adjusting for dietary misreporting, socioeconomic position, BMI, smoking, physical activity and diabetes.

Results

A DP explaining the highest amount of shared variation (4.5%) in plasma Hcy, dietary folate and dietary vitamin B12 highly correlated with folate (r = 0.96), moderately correlated with vitamin B12 (r = 0.27), and weakly correlated with Hcy (r = 0.10). This “high B-vitamin” DP (including folate) was characterised by high intakes of vegetables, fruit and low fibre breakfast cereal, and low intakes of processed meat, white bread, sugar and preserves. No associations were observed between DP z-scores and vascular function at any time point following adjustment for covariates.

Conclusion

This study explored a specific hypothesised pathway linking diet to vascular function. Although we found no consistent evidence for an association between a high B-vitamin DP and vascular function, we did observe an association with CRP and triglycerides in secondary analyses. Further analyses using strongly correlated and biologically relevant intermediate variables are required to refine investigations into diet and CVD in longitudinal cohort data.

Acute lymphoblastic leukemia and genetic variations in BHMT gene: Case-control study and computational characterization

BACKGROUND

Remethylation of homocysteine is catalyzed by B12 dependent methionine synthase (MTR) in all types of cells and by B12 non-dependent betaine homocysteine methyltransferase (BHMT) in liver and kidney cells. Of many etiologies of cancer, an unexplored area is the variations of genes implicated in methylation reaction.

OBJECTIVE

The study evaluated the association of BHMT (rs3733890) with acute lymphoblastic leukemia (ALL), followed by in-silico characterization of variations in BHMT gene.

METHODS

BHMT [rs3733890; c.742G > A, which substitutes an arginine by a glutamine at codon 239 (R239Q)] was screened by Tetra-primer Amplification Refractory Mutation System PCR (T-ARMS-PCR) and confirmed using DNA sequencing. In-silico analysis was conducted using bioinformatics tools.

RESULTS

BHMT (rs3733890) showed an insignificant association with both childhood and adult ALL. Bioinformatics analysis showed that 18 nsSNPs are deleterious, 3 SNPs in 3'-UTR (rs59109725, rs116634518 and rs138578732) alter the miRNA-binding site, and 11 CNVs are present in the BHMT gene. As consequence of BHMT (rs3733890) polymorphism the free energy changes from -101210.1 kJ/mol to -200021.8 kJ/mol.

CONCLUSIONS

BHMT (rs3733890) polymorphism showed no association with ALL. Hence this investigation needs further evaluation in larger sample size and effect of other SNPs, CNVs and miRNA's is required to elucidate the role of BHMT gene in ALL development.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Sildenafil-related cerebral venous sinus thrombosis and papilledema: a case report of a rare entity

We present a rare case of cerebral venous sinus thrombosis associated with long-term and high-dose use of sildenafil. A 29-year-old man was referred to our neuroophthalmology clinic for bilateral visual deterioration and severe headache. He had stage 2 papilledema and other clinical and neurological examinations were normal. He had used the drug for nearly 2 years, two to three times a day. All laboratory parameters including blood count cell, coagulation panels, and genetic tests including methylene-tetrahydrofolate reductase and factor V Leiden mutation were unremarkable. The brain magnetic resonance imaging result confirmed transverse cerebral venous sinus thrombosis (CVST). The opening pressure of cerebrospinal fluid (CSF) was 43 cm H₂O with normal biochemistry and no cells. Clinicians must be aware of the possibility of CVST when the patient uses sildenafil.

Homocysteine Levels and Oxidative Stress Parameters in Patients With Adult ADHD

OBJECTIVE

In our study, we aimed to evaluate the plasma homocysteine levels and oxidative stress parameters in patients with adult ADHD (A-ADHD).

METHOD

Blood samples were taken from 32 A-ADHD patients and 32 controls enrolled in the study and plasma homocysteine, serum folate, vitamin B12, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were determined. Results were compared between the groups.

RESULTS

Patients' plasma homocysteine level was significantly lower and serum folate level was significantly higher than the controls. The means of plasma homocysteine and folate levels were statistically significantly different between the groups ( p < .05). However, a statistically significant difference was not detected between groups for mean serum vitamin B12, TAS, TOS, and OSI levels ( p > .05).

CONCLUSION

Our study suggests that oxidative balance is not impaired in A-ADHD, and contrary to other psychiatric disorders, homocysteine levels were found to be lower.

Potential Links between Impaired One-Carbon Metabolism Due to Polymorphisms, Inadequate B-Vitamin Status, and the Development of Alzheimer's Disease

Alzheimer's disease (AD) is the major cause of dementia and no preventive or effective treatment has been established to date. The etiology of AD is poorly understood, but genetic and environmental factors seem to play a role in its onset and progression. In particular, factors affecting the one-carbon metabolism (OCM) are thought to be important and elevated homocysteine (Hcy) levels, indicating impaired OCM, have been associated with AD. We aimed at evaluating the role of polymorphisms of key OCM enzymes in the etiology of AD, particularly when intakes of relevant B-vitamins are inadequate. Our review indicates that a range of compensatory mechanisms exist to maintain a metabolic balance. However, these become overwhelmed if the activity of more than one enzyme is reduced due to genetic factors or insufficient folate, riboflavin, vitamin B6 and/or vitamin B12 levels. Consequences include increased Hcy levels and reduced capacity to synthetize, methylate and repair DNA, and/or modulated neurotransmission. This seems to favor the development of hallmarks of AD particularly when combined with increased oxidative stress e.g., in apolipoprotein E (ApoE) ε4 carriers. However, as these effects can be compensated at least partially by adequate intakes of B-vitamins, achieving optimal B-vitamin status for the general population should be a public health priority.

Increased homocysteine plasma level is associated with shortened prothrombin time in HIV-infected patients

OBJECTIVE

To find factors associated with increased homocysteine plasma level in HIV-infected patients.

METHODS

Cross-sectional study, carried out as a supplementary task to the standard care of HIV-infected patients. The possible association of increased homocysteine plasma level with blood analyses results was assessed with a multiple linear regression analysis, using the automatic linear modeling available in SPSS version 22.

RESULTS

A total of 145 patients were included. Creatinine was higher than normal in 7 patients (5%), prothrombin time was shortened in 36 patients (25%), and a monoclonal gammopathy was detected in 2 patients (1%). In the regression analysis, an association was found between high homocysteine plasma level and the following variables: low prothrombin time (β coefficient -0.286, confidence interval -1.1854 to -0.754, p < 0.001), high creatinine (coefficient 9.926, confidence interval 6.351-15.246, p < 0.001), low folic acid (coefficient -0.331, confidence interval -0-483 to -0.187, p < 0.001), and low vitamin B12 (coefficient -0.007, confidence interval -0.01 to -0.001, p = 0.005).

CONCLUSION

An association was found between increased homocysteine plasma level and shortened prothrombin time.

A Mendelian Randomization Study of Plasma Homocysteine and Multiple Myeloma

Observational studies have demonstrated an association between elevated homocysteine (Hcy) level and risk of multiple myeloma (MM). However, it remains unclear whether this relationship is causal. We conducted a Mendelian randomization (MR) study to evaluate whether genetically increased Hcy level influences the risk of MM. We used the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism as an instrumental variable, which affects the plasma Hcy levels. Estimate of its effect on plasma Hcy level was based on a recent genome-wide meta-analysis of 44,147 individuals, while estimate of its effect on MM risk was obtained through meta-analysis of case-control studies with 2,092 cases and 4,954 controls. By combining these two estimates, we found that per one standard-deviation (SD) increase in natural log-transformed plasma Hcy levels conferred a 2.67-fold increase in risk for MM (95% confidence interval (CI): 1.12–6.38; P = 2.7 × 10⁻²). Our study suggests that elevated Hcy levels are causally associated with an increased risk of developing MM. Whether Hcy-lowering therapy can prevent MM merits further investigation in long-term randomized controlled trials (RCTs).

Homocysteine levels in schizophrenia patients newly admitted to an acute psychiatric ward

OBJECTIVE

After the discovery of 'homocystinuria syndrome', many studies have suggested that high blood levels of homocysteine may be associated with schizophrenia. The aim of this study was to analyse the association between hyperhomocysteinaemia and schizophrenia.

METHODS

In a population of inpatients suffering from exacerbated schizophrenic disorders (N=100), we evaluated homocysteine levels the day after their admission to an acute psychiatric ward and compared it with that of a non-patient control group (N=110), matched for age and gender. We statistically analysed the correlation between homocysteine levels and selected variables: gender, age, years of illness and number of previous psychiatric admissions as well as Brief Psychiatric Rating Scale, Positive Negative Syndrome Scale and Global Assessment Functioning (GAF) Scores.

RESULTS

We observed elevated homocysteine levels (an increase of 7.84 µM on average per patient) in 32% of the patients, but we did not find any statistically significant difference between the homocysteine levels of our patients and controls. Hyperhomocysteinaemia presented a positive statistically significant correlation with years of illness (p<0.005) and a negative statistically significant correlation with GAF score (p<0.001), but not with other clinical variables.

CONCLUSIONS

Hyperhomocysteinaemia, which occurred in our schizophrenia patients with poor social and relational functioning after many years of illness, could represent an effect of altered lifestyle due to psychosis, but not a specific marker for schizophrenia.

Anti-inflammatory properties of blended edible oil with synergistic antioxidants

BACKGROUND

Blending of oil combines the potency of two edible oils and offers a balance of fatty acids. Various cooking preparations existing across different ethnicities and regions subject oil to different cooking temperatures thereby causing deterioration of the oil due to oxidative stress. In order to prevent the oxidative damage of unsaturated fatty acid, a blend of rice bran oil (RBO) and safflower oil (SO) (70:30) with an antioxidant technology was designed. A controlled trial was carried out to assess the efficacy of the blend on different biomarkers including lipid parameters and some important inflammatory markers that have the potency to lead to various lifestyle diseases.

STUDY DESIGN

A prospective, double-blind, randomized, parallel group study (on 80 adult hyperlipidemic patients) was conducted for 3 months. During the study, all the subjects were recommended lifestyle modifications, which included, exercise regime and diet counseling; oil quantity consumed was 1 L/person/month for both the groups. The subjects were divided into two groups; one group, continued with their regularly consumed oil whereas, the other was given the test oil. Biomarkers assessed were lipid profile and seven other inflammatory markers were assessed.

RESULTS

Low-density lipoprotein cholesterol (LDL-C) the primary marker for cardiovascular diseases showed a decrease of 56.07 ± 04.31 mg/dL and 31.98 ± 03.81 mg/dL (P < 0.001 by analysis of variance [ANOVA]) from baseline in test and control group, respectively, during 3 months. Similar reduction trends were observed for total cholesterol where -52.31 ± 13.04 mg/dL and 31.98 ± 04.12 mg/dL (P < 0.001 by ANOVA, between the groups) were seen in test and control group, respectively. Oxidized LDL and high sensitivity C-reactive protein showed a reduction of 2.23 ± 1.3 units/dL and 0.87 ± 2.85 mg/L in test group whereas; an increase of 1.04 ± 1.73 units/dL and 0.44 ± 2.37 mg/L was seen in the control group, respectively (P < 0.05 by Student's t-test, between the groups).

CONCLUSION

The study showed that the blend of RBO and SO with antioxidant technology along with other lifestyle changes helps lowering of blood lipids and stated inflammatory biomarkers and thus, in turn may help prevent lifestyle diseases.

Transglutaminase 2 is involved in homocysteine-induced activation of human THP-1 monocytes

Aberrant transglutaminase 2 (TG2) expression and protein cross-linking activity have been associated with several chronic neurodegenerative disorders in which inflammatory processes triggered by activated microglia and monocytes play a key role, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. Interestingly, mild-to-moderate hyperhomocysteinemia (HHcy), corresponding to increased plasma homocysteine (Hcy) concentrations in the range 16-60 μM, have recently been associated with the above-cited diseases. Using THP-1 monocytes, here we investigated the role of TG2 in cell response to mildly elevated Hcy concentrations. A five-day incubation with Hcy (∼25 μM) increased reactive oxygen species, peroxide lipids, as well as 8-hydroxyguanosine levels by twofold, and decreased the endogenous cell antioxidant defenses, that is reduced glutathione, by 50% in Hcy-exposed cultures compared with controls (p < 0.01). Hcy-induced oxidative stress was associated with increases in TG2 expression and activity, as well as nuclear factor kappa B activation. Notably, the latter was reduced in the presence of the TG-specific inhibitor R283. Hcy exposure also significantly increased the mRNA levels of tumor necrosis factor alpha, interleukin (IL)-6, and IL-1β, as well as the level of Hcy-inducible endoplasmic reticulum (ER) stress protein, a marker of ER stress, in Hcy-exposed cultures compared with controls. Notably, these effects were dramatically reduced by R283. These preliminary findings indicate that TG2 plays a key role in Hcy-induced activation of THP-1 monocytes, involving oxidative as well as ER stress and inflammation. This underlines the potential of TG2 inhibition in the therapeutic management of inflammatory processes contributing to neurodegenerative disorders associated with mild HHcy.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 1), MEDLINE (1950 to January week 5 2014), EMBASE (1980 to 2014 week 6) and LILACS (1986 to February 2014). We also searched Web of Science (1970 to 7 February 2014). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We measured statistical heterogeneity using the I(2) statistic. We used a random-effects model.

MAIN RESULTS

In this second updated Cochrane Review, we identified no new randomised controlled trials. Therefore, this new version includes 12 randomised controlled trials involving 47,429 participants. In general terms, 75% (9/12) trials had a low risk of bias. Homocysteine-lowering interventions compared with placebo did not significantly affect non-fatal or fatal myocardial infarction (1743/23,590 (7.38%) versus 1247/20,190 (6.17%); RR 1.02, 95% confidence interval (CI) 0.95 to 1.10, I(2) = 0%, high quality evidence), stroke (968/22,348 (4.33%) versus 974/18,957 (5.13%); RR 0.91, 95% CI 0.82 to 1.0, I(2) = 11%, high quality evidence) or death from any cause (2784/22,648 (12.29%) versus 2502/19,250 (10.64%); RR 1.01, 95% CI 0.96 to 1.07, I(2) = 6%, high quality evidence). Homocysteine-lowering interventions compared with placebo did not significantly affect serious adverse events (cancer) (1558/18,130 (8.59%) versus 1334/14,739 (9.05%); RR 1.06, 95% CI 0.98 to 1.13; I(2) = 0%, high quality evidence).

AUTHORS' CONCLUSIONS

This second update of this Cochrane Review found no evidence to suggest that homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination should be used for preventing cardiovascular events. Furthermore, there is no evidence to suggest that homocysteine-lowering interventions are associated with an increased risk of cancer.

Reducing occupational stress with a B-vitamin focussed intervention: a randomized clinical trial: study protocol

Background

Workplace stress in Australia and other western countries has been steadily increasing over the past decade. It can be observed not only in terms of increased compensation claims but also costs due to absenteeism, loss of productivity at work and reduced psychological and physiological health and well-being. Given the cost and pervasive effects of stress in the modern workforce, time efficient and cost-effective interventions capable of reducing occupational stress (or strain) and burnout are urgently required for the improved well-being of stressed employees. One intervention gaining scientific traction is supplementation with nutritional interventions, particularly the B group vitamins.

Methods

This study was developed to examine the effects of B group vitamins on workplace stress and mood variables with a sample of full-time employed older adults who subjectively report feeling stressed. The study is a randomized, double-blind, placebo-controlled, parallel-groups clinical trial where 200 (N = 100/group) participants will be randomized to receive Blackmores® Executive B Stress Formula or placebo daily for a period of 6 months. Participants will be tested at baseline and 6 months post-randomization on workplace stress, cognitive, personality and mood measures, cardiovascular (brachial and aortic systolic and diastolic blood pressures as well as arterial stiffness), biochemical (assays to measure inflammation and safety) as well as genetic assessments (to assess stress processing) and neuroimaging measures (to investigate in vivo mechanisms of action of B vitamins). In addition to this pre- and post- supplementation testing, participants will also complete a battery of self-report questionnaires online to assess their stress and mood once a month for the duration of the study. The primary aim of the study is to investigate the effects of B vitamin supplementation on work related stress. The secondary aims are to explore the mechanisms underpinning any changes in mood or workplace stress due to the B vitamin intervention by examining relationships between cognitive, biological, neuroimaging and cardiovascular variables over 6 months. A subset of 40 participants (N = 20/group) will undergo neuroimaging at baseline and at 6 months using functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) in order to further explore in vivo mechanisms of action of B vitamins.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR):ACTRN12613000294752

Oats and CVD risk markers: a systematic literature review

High consumption of whole-grain food such as oats is associated with a reduced risk of CVD and type 2 diabetes. The present study aimed to systematically review the literature describing long-term intervention studies that investigated the effects of oats or oat bran on CVD risk factors. The literature search was conducted using Embase, Medline and the Cochrane library, which identified 654 potential articles. Seventy-six articles describing sixty-nine studies met the inclusion criteria. Most studies lacked statistical power to detect a significant effect of oats on any of the risk factors considered: 59 % of studies had less than thirty subjects in the oat intervention group. Out of sixty-four studies that assessed systemic lipid markers, thirty-seven (58 %) and thirty-four (49 %) showed a significant reduction in total cholesterol (2–19 % reduction) and LDL-cholesterol (4–23 % reduction) respectively, mostly in hypercholesterolaemic subjects. Few studies (three and five, respectively) described significant effects on HDL-cholesterol and TAG concentrations. Only three out of twenty-five studies found a reduction in blood pressure after oat consumption. None of the few studies that measured markers of insulin sensitivity and inflammation found any effect after long-term oat consumption. Long-term dietary intake of oats or oat bran has a beneficial effect on blood cholesterol. However, there is no evidence that it favourably modulates insulin sensitivity. It is still unclear whether increased oat consumption significantly affects other risk markers for CVD risk, and comprehensive, adequately powered and controlled intervention trials are required to address this question.

Maternal homocysteine in pregnancy and offspring birthweight: epidemiological associations and Mendelian randomization analysis

BACKGROUND

Disturbed one-carbon (1-C) metabolism in the mother is associated with poor fetal growth but causality of this relationship has not been established.

METHODS

We studied the association between maternal total homocysteine and offspring birthweight in the Pune Maternal Nutrition Study (PMNS, Pune, India) and Parthenon Cohort Study (Mysore, India). We tested for evidence of causality within a Mendelian randomization framework, using a methylenetetrahydrofolatereductase (MTHFR) gene variant rs1801133 (earlier known as 677C→T) by instrumental variable and triangulation analysis, separately and using meta-analysis.

RESULTS

Median (IQR) homocysteine concentration and mean (SD) birthweight were 8.6 µmol/l (6.7,10.8) and 2642 g (379) in the PMNS and 6.0 µmol/l (5.1,7.1) and 2871 g (443) in the Parthenon study. Offspring birthweight was inversely related to maternal homocysteine concentration-PMNS: -22 g/SD [95% confidence interval (CI): (-50, 5), adjusted for gestational age and offspring gender]; Parthenon: -57 g (-92, -21); meta-analysis: -40 g (-62, -17)]. Maternal risk genotype at rs1801133 predicted higher homocysteine concentration [PMNS: 0.30 SD/allele (0.14, 0.46); Parthenon: 0.21 SD (0.02, 0.40); meta-analysis: 0.26 SD (0.14, 0.39)]; and lower birthweight [PMNS: -46 g (-102, 11, adjusted for gestational age, offspring gender and rs1801133 genotype); Parthenon: -78 g (-170, 15); meta-analysis: -61 g (-111, -10)]. Instrumental variable and triangulation analysis supported a causal association between maternal homocysteine concentration and offspring birthweight.

CONCLUSIONS

Our findings suggest a causal role for maternal homocysteine (1-C metabolism) in fetal growth. Reducing maternal homocysteine concentrations may improve fetal growth.

Toxic effects of mildly elevated homocysteine concentrations in neuronal-like cells

Epidemiological and experimental evidence indicated that hyperhomocysteinemia is associated with neurodegeneration. However, homocysteine neurotoxic effects have been so far investigated mostly by employing homocysteine concentrations (≥100 µM) much higher than homocysteine mean plasma levels (20 µM) observed in patients with neurodegenerative disorders. While evaluating the effects of a prolonged exposure to ~20 µM homocysteine in neuronal-like differentiated SH-SY5Y cells, we observed a 35% loss of cell viability and a four-fold increase in reactive oxygen species levels in cells incubated with homocysteine for five days compared with controls. Moreover, homocysteine increased by 30% and around two-fold, respectively, the Comet-positive cell number and DNA damage indexes (tail length, T-DNA, olive tail moment) compared with controls. Cell response to homocysteine-induced DNA damage involved the up-regulation of Bax and, at a greater extent, Bcl-2, but not caspase-3, in association with a p53-independent increase of p21 levels; concomitantly, also p16 levels were increased. When looking at time-dependent changes in cyclin expression, we found that a significant up-regulation of cyclins D1, A1, E1, but not B1, concomitant with p21 down-regulation, occurred in cells incubated with homocysteine for three days. However, in line with the observed increase of p21 and p16 levels, a five days incubation with homocysteine induced cyclin down-regulation accompanied by a strong reduction of phosphorylated pRB amounts. These results suggest that, when prolonged, the exposure of neuronal-like cells to mildly elevated homocysteine concentrations triggers oxidative and genotoxic stress involving an early induction of cyclins, that is late repressed by G1-S check-point regulators.

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.

Plasma homocysteine in patients with retinal vein occlusion

PURPOSE

To evaluate total plasma homocysteine (HCY) during fasting and post methionine load test (MLT), serum folate, serum vitamin B12, and methylenetetrahydrofolate reductase (MTHFR) mutation in patients with retinal vein occlusion (RVO) and to examine the association between these risk factors and 2 subtypes of RVO: central (CRVO) and branch (BRVO).

METHODS

This case-control study included 91 Italian patients presenting a first RVO and 71 healthy subjects, matched by age, without history of thromboembolic diseases, glaucoma, or malignancy. Homocysteine fasting and after MLT, serum folate level, serum vitamin B12 level, and other laboratory tests were assessed. Genetic analysis for the C677T MTHFR mutation was performed.

RESULTS

Multivariate logistic regression analysis indicated that hypertension (odds ratio [OR] 2.63; 95% confidence interval [CI] 1.30-5.30; p = 0.007), higher values of fasting HCY (OR 1.16; 95% CI 1.01-1.33; p = 0.03), and low concentrations of vitamin B12 (OR 0.99; 95% CI 0.995-0.999; p = 0.01) were independently correlated with RVO. Moreover, the main determinants for CRVO risk were hypertension (OR 2.46; 95% CI 1.06-5.72; p = 0.04), high values of fasting HCY (OR 1.20; 95% CI 1.02-1.41; p = 0.03), and low concentrations of vitamin B12 (OR 0.99; 95% CI 0.994-0.999; p = 0.008), whereas for BRVO risk only hypertension was significant (OR 2.74; 95% CI 1.24-6.03; p = 0.01). Genotype distribution of the MTHFR C677T mutation did not reveal any significant difference between patients and controls.

CONCLUSIONS

These results suggest that elevated fasting HCY levels, low vitamin B12 levels, and hypertension are associated with a risk of RVO, especially for CRVO. Moreover, our data suggest that only hypertension is associated with BRVO risk.

Vitamin B12: one carbon metabolism, fetal growth and programming for chronic disease

This review brings together human and animal studies and reviews that examine the possible role of maternal vitamin B12 (B12) on fetal growth and its programming for susceptibility to chronic disease. A selective literature review was undertaken to identify studies and reviews that investigate these issues, particularly in the context of a vegetarian diet that may be low in B12 and protein and high in carbohydrate. Evidence is accumulating that maternal B12 status influences fetal growth and development. Low maternal vitamin B12 status and protein intake are associated with increased risk of neural tube defect, low lean mass and excess adiposity, increased insulin resistance, impaired neurodevelopment and altered risk of cancer in the offspring. Vitamin B12 is a key nutrient associated with one carbon metabolic pathways related to substrate metabolism, synthesis and stability of nucleic acids and methylation of DNA which regulates gene expression. Understanding of factors regulating maternal-fetal one carbon metabolism and its role in fetal programming of non communicable diseases could help design effective interventions, starting with maternal nutrition before conception.

[Alterations in the protein content and dysfunction of high-density lipoproteins from hyperhomocysteinemic mice]

AIM

The aim of this study was to evaluate the proteic changes in high-density lipoproteins (HDL) induced by methionine-induced hyperhomocysteinemia in mice and its relationship with two of their main antiatherogenic properties.

METHODS AND RESULTS

The oral administration of methionine resulted in an elevation (~8 times) in the plasma concentration of homocysteine. Hyperhomocysteinemia was inversely correlated with the plasma concentration of HDL cholesterol and its main protein component of HDL, apolipoprotein (apo) A-I, respectively. The cholesterol efflux in vivo from macrophages to HDL was decreased in hyperhomocysteinemic mice compared with the control mice. However, the reverse cholesterol transport from macrophages to feces remained unchanged. On the other hand, the ability of HDL from hyperhomocysteinemic mice to prevent the oxidative modification of low-density lipoproteins (LDL) was found decreased and associated with a concomitant reduction in the plasma activity of paraoxonase-1 (PON1) and the plasma concentration of apoA-I, and with a relative reduction in the apoA-IV content (~1.5 times) in the hyperhomocysteinemic HDL, respectively.

CONCLUSION

The decrease in the ability of HDL from hyperhomocysteinemic mice to prevent LDL from oxidation was associated with a decrease in the apoA-I, PON1 and apoA-IV.