Search

Objectives: Previous studies suggest that folate deficiency may occur in up to one third of patients with severe depression, and that treatment with the vitamin may enhance recovery of the mental state. There are, however, difficulties in interpreting serum and red cell folate assays in some patients, and it has been suggested that total plasma homocysteine is a more sensitive measure of functional folate (and vitamin B12) deficiency. Other studies suggest a link between folate deficiency and impaired metabolism of serotonin, dopamine, and noradrenaline (norepinephrine), which have been implicated in mood disorders. A study of homocysteine, folate, and monoamine metabolism has, therefore, been undertaken in patients with severe depression.Methods: In 46 inpatients with severe DSM III depression, blood counts, serum and red cell folate, serum vitamin B12, total plasma homocysteine, and, in 28 patients, CSF folate, S-adenosylmethionine, and the monoamine neurotransmitter metabolites 5HIAA, HVA, and MHPG were examined. Two control groups comprised 18 healthy volunteers and 20 patients with neurological disorders, the second group undergoing CSF examination for diagnostic purposes.Results: Twenty four depressed patients (52%) had raised total plasma homocysteine. Depressed patients with raised total plasma homocysteine had significant lowering of serum, red cell, and CSF folate, CSF S-adenosylmethionine and all three CSF monoamine metabolites. Total plasma homocysteine was significantly negatively correlated with red cell folate in depressed patients, but not controls.Conclusions: Utilising total plasma homocysteine as a sensitive measure of functional folate deficiency, a biological subgroup of depression with folate deficiency, impaired methylation, and monoamine neurotransmitter metabolism has been identified. Detection of this subgroup, which will not be achieved by routine blood counts, is important in view of the potential benefit of vitamin replacement. [ABSTRACT FROM AUTHOR]

Context: Blood levels of homocysteine may be increased in Alzheimer disease (AD) and hyperhomocysteinemia may contribute to disease pathophysiology by vascular and direct neurotoxic mechanisms. Even in the absence of vitamin deficiency, homocysteine levels can be reduced by administration of high-dose supplements of folic acid and vitamins B(6) and B(12). Prior studies of B vitamins to reduce homocysteine in AD have not had sufficient size or duration to assess their effect on cognitive decline.Objective: To determine the efficacy and safety of B vitamin supplementation in the treatment of AD.Design, Setting, and Patients: A multicenter, randomized, double-blind controlled clinical trial of high-dose folate, vitamin B(6), and vitamin B(12) supplementation in 409 (of 601 screened) individuals with mild to moderate AD (Mini-Mental State Examination scores between 14 and 26, inclusive) and normal folic acid, vitamin B(12), and homocysteine levels. The study was conducted between February 20, 2003, and December 15, 2006, at clinical research sites of the Alzheimer Disease Cooperative Study located throughout the United States.Intervention: Participants were randomly assigned to 2 groups of unequal size to increase enrollment (60% treated with high-dose supplements [5 mg/d of folate, 25 mg/d of vitamin B(6), 1 mg/d of vitamin B(12)] and 40% treated with identical placebo); duration of treatment was 18 months.Main Outcome Measure: Change in the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-cog).Results: A total of 340 participants (202 in active treatment group and 138 in placebo group) completed the trial while taking study medication. Although the vitamin supplement regimen was effective in reducing homocysteine levels (mean [SD], -2.42 [3.35] in active treatment group vs -0.86 [2.59] in placebo group; P < .001), it had no beneficial effect on the primary cognitive measure, rate of change in ADAS-cog score during 18 months (0.372 points per month for placebo group vs 0.401 points per month for active treatment group, P = .52; 95% confidence interval of rate difference, -0.06 to 0.12; based on the intention-to-treat generalized estimating equations model), or on any secondary measures. A higher quantity of adverse events involving depression was observed in the group treated with vitamin supplements.Conclusion: This regimen of high-dose B vitamin supplements does not slow cognitive decline in individuals with mild to moderate AD.Trial Registration: clinicaltrials.gov Identifier: NCT00056225. [ABSTRACT FROM AUTHOR]

Objective:To evaluate the independent and joint effects of dietary folate, vitamin B12 consumption and methylenetetrahydrofolate reductase (MTHFR) polymorphisms (677C>T and 1298A>C) on the circulating folate and homocysteine (Hcy) levels among Mexican women of reproductive age.Design:A cross-sectional, population-based study.Subjects:The first 130 healthy non-pregnant women (aged 16–34 years) who agreed to participate in a reproductive cohort in Morelos, Mexico.Main outcome measurements:Dietary intakes of vitamin B12 and folate were estimated using a semiquantitative food frequency questionnaire. MTHFR 677C>T and 1298A>C polymorphisms were ascertained using the PCR-based method. Serum levels of Hcy and folate were determined using high-performance liquid chromatography and radioimmunoassay, respectively.Results:Genotype frequencies for the MTHFR 677C>T polymorphism were 21.5% (CC), 52.3% (CT) and 26.2% (TT) among Mexican women. Of the population, 22% had the MTHFR 1298AC genotype, while no individual carried the 1298CC genotype. We observed an increased level of Hcy among carriers of the 677TT genotype, compared to carriers of the 677CC genotype. The highest level of Hcy was observed among MTHFR 677TT carriers with low B12 intake (<2.0 μg/day), which resulted with a significant interaction (P=0.01).Conclusion:Vitamin B12 is an important determinant of Hcy levels in Mexico. Supplementation of folic acid with vitamin B12 may be preferable when the MTHFR 677T variant allele is prevalent.Sponsorship:Fogarty International Center of NIH, CONACyT MexicoEuropean Journal of Clinical Nutrition (2006) 60, 691–697. doi:10.1038/sj.ejcn.1602370; published online 18 January 2006 [ABSTRACT FROM AUTHOR]

Summary. Hyperhomocysteinemia is common in Alzheimer’s disease and is negatively correlated with cognitive function. Hyperhomocysteinemia can increase S-adenosylhomocysteine (SAH), a potent methyltransferase inhibitor. This study investigates the role of brain SAH in the cognitive and neurological disruption in Alzheimer’s disease. SAH was significantly (26%) higher in prefrontal cortex of Alzheimer patients than normals. Brain homogenates from Alzheimer patients inhibited an exogenous methyltransferase 15% more than normal homogenates (P < .001). Brain SAH levels correlated (r=.508) with methyltransferase inhibition by brain homogenates. Methyltransferase inhibition by Alzheimer brain homogenates correlated inversely with cognitive function as determined by MMSE (r=-0.36). Phenylethanolamine N-methyltransferase (PNMT) and catechol O-methyltransferase (COMT) activities were more than 30% lower (P<0.001) in Alzheimer than normal brains. Brain PNMT activity correlated significantly with cognitive function (r=0.243), age of Alzheimer’s onset (r=0.272), and choline acetyltransferase activity (r=0.333), but negatively with neurofibrillary tangles (r=-0.332). COMT activity also correlated significantly with cognitive function (r=0.324), age of disease onset (r=0.209), choline acetyltransferase activity (r=0.326), levels of synaptophysin (r=0.506), and negatively with tangles (r=-0.216 P=0.039). Elevated SAH in Alzheimer brain inhibits methyltransferases and is related to markers of disease progression and cognitive impairment. [ABSTRACT FROM AUTHOR]

The role of hyperhomocysteinemia as independent risk factor for stroke needs to be confirmed. The aims of our study were to assess (i) the association between risk of stroke and increasing values of plasma homocysteine and (ii) the interaction between mild hyperhomocysteinemia and conventional vascular risk factors. We studied 161 consecutive patients with first-ever ischemic stroke classified using TOAST criteria and 152 neurologically healthy controls. Homocysteine was measured using high performance liquid chromatography (HPLC). Homocysteinemia was elevated in all stroke subtypes: 13.0±2.5 µmol/l in patients with cardioembolic disease, 13.9±5.4 µmol/l in those with small vessel diseases, 15.5±6.8 µmol/l in cases of undetermined stroke, and 17.8±13.5 µmol/l in patients with large vessel disease. Mean homocysteinemia was 8.10 µmol/l (SD=2.5) in controls. The logistic regression analysis showed that important independent risk factors for ischemic stroke were hypertension (p<0.0001; OR= 3.205; 95% CI, 1.788–5.742), hyperhomocysteinemia (p<0.0001; OR=1.425; 95% CI, 1.300–1562) and hyperlipidemia (p=0.018; OR=2.243; 95% CI, 1.147–4.385). Hyperhomocyst(e)inemia is an independent risk factor for all stroke subtypes and should be routinely measured and treated in stroke patients. [ABSTRACT FROM AUTHOR]

Metabolite profiling in succinate semialdehyde dehydrogenase (SSADH; Aldh5a1[sup –/–]) deficient mice previously revealed elevated γ-hydroxybutyrate (GHB) and total GABA in urine and total brain and liver extracts. In this study, we extend our metabolic characterization of these mutant mice by documenting elevated GHB and total GABA in homogenates of mutant kidney, pancreas and heart. We quantified β-alanine (a GABA homolog and putative neurotransmitter) to address its potential role in pathophysiology. We found normal levels of β-alanine in urine and total homogenates of mutant brain, heart and pancreas, but elevated concentrations in mutant kidney and liver extracts. Amino acid analysis in mutant total brain homogenates revealed no abnormalities except for significantly decreased glutamine, which was normal in mutant liver and kidney extracts. Regional amino acid analysis (frontal cortex, parietal cortex, hippocampus and cerebellum) in mutant mice confirmed glutamine results. Glutamine synthetase protein and mRNA levels in homogenates of mutant mouse brain were normal. We profiled organic acid patterns in mutant brain homogenates to assess brain oxidative metabolism and found normal concentrations of Kreb's cycle intermediates but increased 4,5-dihydroxyhexanoic acid (a postulated derivative of succinic semialdehyde) levels. We conclude that SSADH-deficient mice represent a valid metabolic model of human SSADH deficiency, manifesting focal neurometabolic abnormalities which could provide key insights into pathophysiologic mechanisms. [ABSTRACT FROM AUTHOR]

During open trials of intravenous and oral S-adenosyl methionine (SAM) and a placebo-controlled trial of intravenous SAM in 29 patients, 25 patients had SAM and four had placebo (27 courses of SAM, two of the patients receiving two trials a piece). Nine of 11 bipolar patients (all SAM-treated) switched into elevated mood state (hypomania, mania and euphoria) and two did not respond. Six endogenous unipolar patients improved and five did not. No non-endogenous patient or placebo patient responded for more than 14 days. No unipolar patient switched into elated mood. In eleven (38%) trials and nine (33%) patients there was a switch from depression to elation. Biochemical data from the cerebrospinal fluid of eight patients suggested that the role of the dopaminergic system should be further explored. [ABSTRACT FROM AUTHOR]

Non-ketotic hyperglycinaemia (NKH) is a rare, severe brain disease caused by deficient glycine cleavage enzyme complex activity resulting in elevated glycine concentrations. Recent experience suggests that factors in addition to glycine kinetics are involved in its pathogenesis. The glycine cleavage reaction through the formation of methylenetetrahydrofolate is an important one-methyl group donor. A deficiency in one-methyl group metabolites, in particular of choline, has been hypothesized in NKH. We investigated metabolites involved in one-methyl group metabolism in plasma and CSF of 8 patients with NKH, and monitored the effect of treatment with choline in one patient. Plasma and CSF choline and phosphatidylcholine concentrations were normal, except for a low plasma choline in the single neonate studied. Choline treatment did not change brain choline content, and was not associated with clinical or radiological improvement. Methionine concentrations and, in one-patient, S-adenosylmethionine and 5-methyltetrahydrofolate concentrations were normal in CSF. Homocysteine concentrations in CSF, however, were slightly but consistently elevated in all four patients examined, but cysteine, cysteinylglycine and glutathione were normal. Serine is important in the transfer of one-methyl groups from mitochondria to cytosol. Serine concentrations were normal in plasma and CSF, but dropped to below normal in CSF in three patients on benzoate treatment. These observations add to our understanding of the complex metabolic disturbances in NKH. [ABSTRACT FROM AUTHOR]

Background: Homocysteine may be involved in the pathogenesis of late onset Alzheimer's disease. It is implicated in the metabolism of several important pathways in the brain. Methylmalonic acid (MMA) is related to the metabolism of branched chained amino acids and fatty acids.Objectives: To compare cerebrospinal fluid (CSF) total homocysteine and MMA in elderly subjects, patients with Alzheimer's disease, and younger healthy controls.Subjects: CSF samples were obtained from 33 patients under 20 years of age; 28 patients aged 21 to 60 years; 22 normal elderly subjects aged over 60; and 38 Alzheimer patients aged over 60.Results: CSF total homocysteine increased with age (mean (SD): 57 (35) nmol/l in the youngest group v 123 (89) nmol/l in the elderly group (p<0.001)). There was no difference between the elderly group and Alzheimer patients (115 (62) nmol/l). CSF MMA did not differ in the elderly group and the Alzheimer group (38 (13) v 35 (14) ng/ml). In the youngest group, it was significantly higher (60 (15) ng/ml).Conclusions: CSF total homocysteine is not increased in Alzheimer's disease compared with age matched controls. CSF total homocysteine was correlated with age. The decrease in CSF MMA levels with age eliminates a lack of vitamin B-12 at neuronal level. [ABSTRACT FROM AUTHOR]

Cerebrospinal fluid (CSF) S-adenosylmethionine (SAM) levels were significantly lower in severely depressed patients than in a neurological control group. The administration of SAM either intravenously or orally is associated with a significant rise of CSF SAM, indicating that it crosses the blood-brain barrier in humans. These observations provide a rational basis for the antidepressant effect of SAM, which has been confirmed in several countries. CSF SAM levels were low in a group of patients with Alzheimer's dementia suggesting a possible disturbance of methylation in such patients and the need for trials of SAM treatment. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the letters that commented on the article by P. S. A. Godfrey and colleagues in a 1990 issue regarding the enhancement of recovery from mental illness by methylfolate.

A letter to the editor is presented about switching mechanisms in three of 12 depressives receiving intravenous S-adenosylmethionine.

S-Adenosyl-L-methionine (SAMe), a metabolite present in all living cells, plays a central role in cellular biochemistry as a precursor to methylation, aminopropylation, and transsulfuration pathways. As such, SAMe has been studied extensively since its chemical structure was first described in 1952. Decades of research on the biochemical and molecular roles of SAMe in cellular metabolism have provided an extensive foundation for its use in clinical studies, including those on depression, dementia, vacuolar myelopathy, liver disease, and osteoarthritis. This article provides an overview of the biochemical, molecular, and therapeutic effects of this pleiotrophic molecule. [ABSTRACT FROM AUTHOR]

The article presents an abstract of the study "COMT-Dependent Protection of Dopamine Neurons Against L-Dopa Toxicity by Methionine, Dimethionine and S-Adenosylmethionine." The study will be presented at a joint meeting of the International Society for Neurochemistry and the European Society for Neurochemistry which will be organized in Berlin, Germany, from August 8-14, 1999. The study reveals that inhibition of COMT in central nervous system may aggravate L-dopa neurotoxicity.

A letter to the editor is presented in response to an article about affective switch mechanisms in the January 1989 issue.