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Zhilyaeva T, Kasyanov E, Pyatoikina A, Blagonravova A, Mazo G. The association of serum folate levels with schizophrenia symptoms. Zh Nevrol Psikhiatr Im S S Korsakova 2022; 122:128-135. [DOI: 10.17116/jnevro2022122081128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Tomioka Y, Kinoshita M, Umehara H, Nakayama T, Watanabe SY, Nakataki M, Numata S, Ohmori T. Association between serum folate levels and schizophrenia based on sex. Psychiatry Clin Neurosci 2020; 74:466-471. [PMID: 32445495 DOI: 10.1111/pcn.13074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/17/2020] [Accepted: 05/10/2020] [Indexed: 02/06/2023]
Abstract
AIM Sex differences in serum folate concentrations are well known, but no studies have investigated the association between serum folate levels and schizophrenia based on sex. With this study in a Japanese population, we examined the difference in serum folate levels between patients with schizophrenia and non-psychiatric controls stratified by sex. The relations among serum folate levels, plasma total homocysteine (tHcy), and serum vitamin B6 (pyridoxal) levels were also examined using data from our previous studies. METHODS The serum folate concentrations of 482 patients diagnosed with schizophrenia and 1350 non-psychiatric control subjects were measured. We conducted an analysis of covariance to examine the differences in serum folate levels between the two groups based on sex. Spearman's rank correlation was used to evaluate the relations among folate, tHcy, and vitamin B6 levels. RESULTS In the control group, serum folate concentrations were higher in women than in men. Lower levels of serum folate were observed in both male and female patients with schizophrenia. An inverse correlation between serum folate and plasma tHcy and a weak positive correlation between serum folate and vitamin B6 were observed in the combined cohort. CONCLUSION Our findings suggest that: (i) a low serum folate level may be associated with schizophrenia regardless of sex; and (ii) folate administration may be beneficial for the treatment of schizophrenia. In schizophrenic patients with low serum folate levels, folate administration might result in improvements in high tHcy and an increase in low vitamin B6 levels.
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Affiliation(s)
- Yukiko Tomioka
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Makoto Kinoshita
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Hidehiro Umehara
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Tomohiko Nakayama
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Shin-Ya Watanabe
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Masahito Nakataki
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Shusuke Numata
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Tetsuro Ohmori
- Department of Psychiatry, Institute of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
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Enko D, Meinitzer A, Brandmayr W, Halwachs-Baumann G, Schnedl WJ, Kriegshäuser G. Association between increased plasma levels of homocysteine and depression observed in individuals with primary lactose malabsorption. PLoS One 2018; 13:e0202567. [PMID: 30138390 PMCID: PMC6107192 DOI: 10.1371/journal.pone.0202567] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/06/2018] [Indexed: 12/28/2022] Open
Abstract
Background Current literature proposes associations between homocysteine (HCY), folic acid (FA), vitamin B12 metabolism and depression. However, the exact underlying biological mechanisms remain unclear. This study aimed at evaluating a possible link between primary adult-type lactose malabsorption (PALM), HCY, FA and vitamin B12 metabolism and depressive disorder. Methods Plasma levels of HCY, FA and vitamin B12 were determined in 78 patients with PALM and 160 individuals with lactase persistence sub-grouped by the presence or absence of major depression. Results In 78 patients with PALM, the subgroup of 22 individuals with major depression showed significantly higher median (interquartile range) HCY (10.10 [8.46–12.03] vs. 8.9 [7.54–9.86] μmol/L, p = 0.029) and lower plasma FA levels (5.7 [4.68–9.14] vs. 6.95 [5.24–10.56] μmol/L, p = 0.272) compared to the subgroup of 56 individuals without depression, respectively. No such associations could be observed for those 160 individuals without PALM (i.e., lactase persistence) Plasma HCY levels were positively correlated with depressive symptoms (p = 0.052), and showed negative correlations with FA (p = < 0.001) and vitamin B12 (p = 0.029), respectively. Conclusion Depressed individuals with PALM were found with significantly higher HCY and lower FA levels compared to non-depressed individuals with PALM, however, this association was absent in the subgroup of lactase persistent individuals. These findings suggest an association between increased HCY levels, lactose malabsorption and depression.
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Affiliation(s)
- Dietmar Enko
- Institute of Clinical Chemistry and Laboratory Medicine, General Hospital Steyr, Steyr, Austria
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
- * E-mail:
| | - Andreas Meinitzer
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Wolfgang Brandmayr
- Department of Psychiatry and Psychotherapeutic Medicine, General Hospital Steyr, Steyr, Austria
| | | | | | - Gernot Kriegshäuser
- Institute of Clinical Chemistry and Laboratory Medicine, General Hospital Steyr, Steyr, Austria
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
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Biochemical, physiological and clinical effects of l-methylfolate in schizophrenia: a randomized controlled trial. Mol Psychiatry 2018; 23:316-322. [PMID: 28289280 PMCID: PMC5599314 DOI: 10.1038/mp.2017.41] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 01/26/2017] [Indexed: 12/25/2022]
Abstract
Folic acid supplementation confers modest benefit in schizophrenia, but its effectiveness is influenced by common genetic variants in the folate pathway that hinder conversion to its active form. We examined physiological and clinical effects of l-methylfolate, the fully reduced and bioactive form of folate, in schizophrenia. In this randomized, double-blind trial, outpatients with schizophrenia (n=55) received l-methylfolate 15 mg or placebo for 12 weeks. Patients were maintained on stable doses of antipsychotic medications. The pre-defined primary outcome was change in plasma methylfolate at 12 weeks. Secondary outcomes included change in symptoms (Positive and Negative Syndrome Scale (PANSS), Scale for Assessment of Negative Symptoms, Calgary Depression Scale for Schizophrenia), cognition (Measurement and Treatment Research to Improve Cognition in Schizophrenia composite) and three complementary magnetic resonance imaging measures (working memory-related activation, resting connectivity, cortical thickness). Primary, mixed model, intent-to-treat analyses covaried for six genetic variants in the folate pathway previously associated with symptom severity and/or response to folate supplementation. Analyses were repeated without covariates to evaluate dependence on genotype. Compared with placebo, l-methylfolate increased plasma methylfolate levels (d=1.00, P=0.0009) and improved PANSS Total (d=0.61, P=0.03) as well as PANSS Negative and General Psychopathology subscales. Although PANSS Total and General Psychopathology changes were influenced by genotype, significant PANSS Negative changes occurred regardless of genotype. No treatment differences were seen in other symptom rating scales or cognitive composite scores. Patients receiving l-methylfolate exhibited convergent changes in ventromedial prefrontal physiology, including increased task-induced deactivation, altered limbic connectivity and increased cortical thickness. In conclusion, l-methylfolate supplementation was associated with salutary physiological changes and selective symptomatic improvement in this study of schizophrenia patients, warranting larger clinical trials. ClinicalTrials.gov, NCT01091506.
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Yadav U, Kumar P, Gupta S, Rai V. Role of MTHFR C677T gene polymorphism in the susceptibility of schizophrenia: An updated meta-analysis. Asian J Psychiatr 2016; 20:41-51. [PMID: 27025471 DOI: 10.1016/j.ajp.2016.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 12/31/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme of folate/homocysteine metabolic pathway. C677T polymorphism of MTHFR gene was reported as risk factor for congenital defects, metabolic and neuropsychiatric disorders. Numerous case-control studies investigated C677T polymorphism as risk factor for schizophrenia but results of these studies were contradictory. To draw a conclusion, a meta-analysis of all available case-control studies was performed. PubMed, Google Scholar, Springer Link and Elsevier databases were searched for eligible case-control studies. Pooled odds ratio with 95%CI was used as an association measure and all statistical analyses were performed by Open Meta-Analyst and MIX software. Total 38 studies with 10,069 cases and 13,372 controls were included in the present meta-analysis. Results of meta-analysis showed significant associated between C677T polymorphism and risk of schizophrenia (ORTvsC=1.18, 95%CI=1.10-1.27, p=<0.001; ORCTvsCC=1.10, 95%CI=1.04-1.17, p=<0.001; ORTTvsCC=1.40, 95%CI=1.20-1.64, p=<0.001; ORTT+CTvsCC=1.19, 95%CI=1.09-1.30, p=<0.001). We also performed subgroup and sensitivity analyses. Subgroup analysis was done according to ethnicity and significant association was found between C677T polymorphism and risk of schizophrenia in all three ethnic populations-African (OR=2.51; 95%CI=1.86-3.40; p=<0.001), Asian (OR=1.21; 95%CI=1.10-1.33; p=<0.001) and Caucasian (OR=1.07; 95%CI=1.01-1.14; p=0.01). In conclusion the results of the present meta-analysis suggested that the MTHFR C677T polymorphism is a risk factor for schizophrenia.
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Affiliation(s)
- Upendra Yadav
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur 222 003, UP, India
| | - Pradeep Kumar
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur 222 003, UP, India
| | - Sanjay Gupta
- Department of Psychiatry, IMS, Banaras Hindu University, Varanasi, India
| | - Vandana Rai
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur 222 003, UP, India.
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Wang D, Zhai JX, Liu DW. Serum folate levels in schizophrenia: A meta-analysis. Psychiatry Res 2016; 235:83-9. [PMID: 26652840 DOI: 10.1016/j.psychres.2015.11.045] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 10/18/2015] [Accepted: 11/24/2015] [Indexed: 02/03/2023]
Abstract
To clarify the relationship between serum folate and schizophrenia (SZ) risk, the meta-analysis was conducted. PubMed, Embase, and Web of Science were searched without language restrictions. Weighted mean difference (WMD) as a summary statistic was used in this meta-analysis. Subgroup analyses by publication language (English and non-English), ethnicity (Caucasian, Asian, African, Latino, and mixed population), duration (acute, chronic, patients including both acute and chronic SZ, and not mentioned about either chronic or acute), measurement time (before drugs using and after drugs using), gender (male and female) and age (<50 years old and >50 years old) were performed. Power analysis was also conducted to detect the reliability of the meta-analyses' results. In summary, the subgroups which failed to detect significant decreased associations were always with lower statistic power and could not be confirmed. The results supported that decreased serum folate was associated with SZ risk in total studies and subgroups of English publications, Caucasians, Asians, acute SZ patients, measurement after drugs using in SZ patients, and age<50 with the great enough powers, respectively. In conclusion, the present meta-analysis found that folate deficiency is associated to SZ, and subgroups which did not reach enough statistical power need further investigation in the future.
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Affiliation(s)
- Dan Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Hebei Medical University, Shijiazhuang 050017, Hebei Province, China; Library, Hebei Medical University, Shijiazhuang 050017, Hebei Province, China
| | - Jun-Xia Zhai
- Department of Novelty Retrieval, Institute of Hebei Medical Information, Shijiazhuang 050071, Hebei Province, China
| | - Dian-Wu Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Hebei Medical University, Shijiazhuang 050017, Hebei Province, China.
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Roffman JL, Lamberti JS, Achtyes E, Macklin EA, Galendez GC, Raeke LH, Silverstein NJ, Smoller JW, Hill M, Goff DC. Randomized multicenter investigation of folate plus vitamin B12 supplementation in schizophrenia. JAMA Psychiatry 2013; 70:481-9. [PMID: 23467813 PMCID: PMC4394629 DOI: 10.1001/jamapsychiatry.2013.900] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IMPORTANCE More effective treatments are needed for negative symptoms of schizophrenia, which are typically chronic, disabling, and costly. Negative symptoms have previously been associated with reduced blood folate levels, especially among patients with low-functioning variants in genes that regulate folate metabolism, suggesting the potential utility of folate supplementation. OBJECTIVES To determine whether folic acid plus vitamin B12 supplementation reduces negative symptoms of schizophrenia and whether functional variants in folate-related genes influence treatment response. DESIGN Parallel-group, randomized, double-blind, placebo-controlled clinical trial of 16 weeks of treatment with 2 mg of folic acid and 400 μg of vitamin B12. SETTING Three community mental health centers affiliated with academic medical centers in the United States. PARTICIPANTS Outpatients with chronic schizophrenia who were psychiatrically stable but displayed persistent symptoms despite antipsychotic treatment. Eligible patients were 18 to 68 years old, were treated with an antipsychotic agent for 6 months or more at a stable dose for 6 weeks or more, and scored 60 or more on the Positive and Negative Syndrome Scale. INTERVENTION One hundred forty subjects were randomized to receive daily oral folic acid plus vitamin B12 or placebo. MAIN OUTCOME MEASURES Change in negative symptoms (Scale for the Assessment of Negative Symptoms [SANS]), as well as positive and total symptoms (Positive and Negative Syndrome Scale). RESULTS Folate plus vitamin B12 improved negative symptoms significantly compared with placebo (group difference, -0.33 change in SANS score per week; 95% CI, -0.62 to -0.05) when genotype was taken into account but not when genotype was excluded. An interaction of the 484C>T variant of FOLH1 (rs202676) with treatment was observed (P = .02), where only patients homozygous for the 484T allele demonstrated significantly greater benefit with active treatment (-0.59 change in SANS score per week; 95% CI, -0.99 to -0.18). In parallel, we observed an inverse relationship between red blood cell folate concentration at baseline and 484C allele load (P = .03), which persisted until 8 weeks of treatment. Change in positive and total symptoms did not differ between treatment groups. CONCLUSIONS Folate plus vitamin B12 supplementation can improve negative symptoms of schizophrenia, but treatment response is influenced by genetic variation in folate absorption. These findings support a personalized medicine approach for the treatment of negative symptoms. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00611806.
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Affiliation(s)
- Joshua L. Roffman
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - J. Steven Lamberti
- Department of Psychiatry, University of Rochester Medical Center, Rochester, NY
| | - Eric Achtyes
- Cherry Street Health Services and Department of Psychiatry, Michigan State University College of Human Medicine, Grand Rapids, MI
| | - Eric A. Macklin
- Massachusetts General Hospital Biostatistics Center and Harvard Medical School, Boston, MA
| | - Gail C. Galendez
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Lisa H. Raeke
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Noah J. Silverstein
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Jordan W. Smoller
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA,Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital
| | - Michele Hill
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Donald C. Goff
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA
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Roffman JL, Brohawn DG, Nitenson AZ, Macklin EA, Smoller JW, Goff DC. Genetic variation throughout the folate metabolic pathway influences negative symptom severity in schizophrenia. Schizophr Bull 2013; 39:330-8. [PMID: 22021659 PMCID: PMC3576161 DOI: 10.1093/schbul/sbr150] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Low serum folate levels previously have been associated with negative symptom risk in schizophrenia, as has the hypofunctional 677C>T variant of the MTHFR gene. This study examined whether other missense polymorphisms in folate-regulating enzymes, in concert with MTHFR, influence negative symptoms in schizophrenia, and whether total risk allele load interacts with serum folate status to further stratify negative symptom risk. Medicated outpatients with schizophrenia (n = 219), all of European origin and some included in a previous report, were rated with the Positive and Negative Syndrome Scale. A subset of 82 patients also underwent nonfasting serum folate testing. Patients were genotyped for the MTHFR 677C>T (rs1801133), MTHFR 1298A>C (rs1801131), MTR 2756A>G (rs1805087), MTRR 203A>G (rs1801394), FOLH1 484T>C (rs202676), RFC 80A>G (rs1051266), and COMT 675G>A (rs4680) polymorphisms. All genotypes were entered into a linear regression model to determine significant predictors of negative symptoms, and risk scores were calculated based on total risk allele dose. Four variants, MTHFR 677T, MTR 2756A, FOLH1 484C, and COMT 675A, emerged as significant independent predictors of negative symptom severity, accounting for significantly greater variance in negative symptoms than MTHFR 677C>T alone. Total allele dose across the 4 variants predicted negative symptom severity only among patients with low folate levels. These findings indicate that multiple genetic variants within the folate metabolic pathway contribute to negative symptoms of schizophrenia. A relationship between folate level and negative symptom severity among patients with greater genetic vulnerability is biologically plausible and suggests the utility of folate supplementation in these patients.
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Affiliation(s)
- Joshua L. Roffman
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA,To whom correspondence should be addressed; Massachusetts General Hospital, 149 13th Street, Room 2606, Charlestown, MA 02129; tel: 617-724-1920, fax: 617-726-4078, e-mail:
| | - David G. Brohawn
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Adam Z. Nitenson
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Eric A. Macklin
- Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Jordan W. Smoller
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Donald C. Goff
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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Saetre P, Grove J, Børglum AD, Mors O, Werge T, Andreassen OA, Vares M, Agartz I, Terenius L, Jönsson EG. Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and age at onset of schizophrenia: no consistent evidence for an association in the Nordic population. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:981-6. [PMID: 23076983 PMCID: PMC3739001 DOI: 10.1002/ajmg.b.32104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 09/24/2012] [Indexed: 01/16/2023]
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is an enzyme involved in metabolic pathways of importance for nucleotide synthesis and methylation of DNA, membranes, proteins and lipids. The MTHFR gene includes a common polymorphism (rs1801133 or C677T), which is associated with enzyme activity. The T-allele of the C677T polymorphism has been associated with earlier age at onset of schizophrenia in a Scandinavian population, although no association was found in replication attempts in other populations. Extending the study to five Nordic samples consisting of 2,198 patients with schizophrenia, including the original Scandinavian samples, there was no significant association between MTHFR C677T polymorphism and age at onset in schizophrenia. The present results do not suggest that the investigated MTHFR polymorphism has any significant influence on age at onset of schizophrenia in the Nordic population.
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Affiliation(s)
- Peter Saetre
- Department of Clinical Neuroscience, Karolinska Institutet and HospitalStockholm, Sweden
| | - Jakob Grove
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
- Bioinformatics Research Centre (BiRC), Aarhus UniversityAarhus, Denmark
- deCODE GeneticsReykjavik, Iceland
| | - Anders D Børglum
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
- Center for Psychiatric Research, Aarhus University HospitalAarhus, Denmark
| | - Ole Mors
- Center for Psychiatric Research, Aarhus University HospitalAarhus, Denmark
| | - Thomas Werge
- Research Institute of Biological Psychiatry, Mental Health Center Sct. Hans, Copenhagen University HospitalRoskilde, Denmark
| | - Ole A Andreassen
- Institute of Psychiatry, University of OsloOslo, Norway
- Department Psychiatry, Oslo University Hospital—UllevålOslo, Norway
| | - Maria Vares
- Department of Clinical Neuroscience, Karolinska Institutet and HospitalStockholm, Sweden
| | - Ingrid Agartz
- Department of Clinical Neuroscience, Karolinska Institutet and HospitalStockholm, Sweden
- Institute of Psychiatry, University of OsloOslo, Norway
- Department of Psychiatry, Section Vinderen, University of OsloOslo, Norway
| | - Lars Terenius
- Department of Clinical Neuroscience, Karolinska Institutet and HospitalStockholm, Sweden
| | - Erik G Jönsson
- Department of Clinical Neuroscience, Karolinska Institutet and HospitalStockholm, Sweden
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van Loo KMJ, Martens GJM. Genetic and environmental factors in complex neurodevelopmental disorders. Curr Genomics 2011; 8:429-44. [PMID: 19412416 PMCID: PMC2647153 DOI: 10.2174/138920207783591717] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 11/07/2007] [Accepted: 11/09/2007] [Indexed: 12/14/2022] Open
Abstract
Complex neurodevelopmental disorders, such as schizophrenia, autism, attention deficit (hyperactivity) disorder, (manic) depressive illness and addiction, are thought to result from an interaction between genetic and environmental factors. Association studies on candidate genes and genome-wide linkage analyses have identified many susceptibility chromosomal regions and genes, but considerable efforts to replicate association have been surprisingly often disappointing. Here, we summarize the current knowledge of the genetic contribution to complex neurodevelopmental disorders, focusing on the findings from association and linkage studies. Furthermore, the contribution of the interaction of the genetic with environmental and epigenetic factors to the aetiology of complex neurodevelopmental disorders as well as suggestions for future research are discussed.
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Affiliation(s)
- K M J van Loo
- Department of Molecular Animal Physiology, Donders Institute for Neuroscience, Nijmegen Center for Molecular Life Sciences (NCMLS), Faculty of Science, Radboud University Nijmegen, Geert Grooteplein Zuid 28, 6525 GA Nijmegen, The Netherlands
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Tosh DN, Fu Q, Callaway CW, McKnight RA, McMillen IC, Ross MG, Lane RH, Desai M. Epigenetics of programmed obesity: alteration in IUGR rat hepatic IGF1 mRNA expression and histone structure in rapid vs. delayed postnatal catch-up growth. Am J Physiol Gastrointest Liver Physiol 2010; 299:G1023-9. [PMID: 20813916 PMCID: PMC2993166 DOI: 10.1152/ajpgi.00052.2010] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Maternal food restriction (FR) during pregnancy results in intrauterine growth-restricted (IUGR) offspring that show rapid catch-up growth and develop metabolic syndrome and adult obesity. However, continued nutrient restriction during nursing delays catch-up growth and prevents development of obesity. Epigenetic regulation of IGF1, which modulates growth and is synthesized and secreted by the liver, may play a role in the development of these morbidities. Control (AdLib) pregnant rats received ad libitum food through gestation and lactation, and FR dams were exposed to 50% food restriction from days 10 to 21. FR pups were nursed by either ad libitum-fed control dams (FR/AdLib) or FR dams (FR/FR). All pups were weaned to ad libitum feed. Maternal FR resulted in IUGR newborns with significantly lower liver weight and, with the use of chromatin immunoprecipitation, decreased dimethylation at H3K4 in the IGF1 region was observed. Obese adult FR/AdLib males had decreased dimethylation and increased trimethylation of H3K4 in the IGF1 region. This corresponded to an increase in mRNA expression of IGF1-A (134 ± 5%), IGF1-B (165 ± 6%), IGF1 exon 1 (149 ± 6%), and IGF1 exon 2 (146 ± 7%) in the FR/AdLib compared with the AdLib/AdLib control group. In contrast, nonobese FR/FR had significantly higher IGF1-B mRNA levels (147 ± 19%) than controls with no difference in IGF1-A, exon 1 or exon 2. Modulation of the rate of IUGR newborn catch-up growth may thus protect against IGF1 epigenetic modifications and, consequently, obesity and associated metabolic abnormalities.
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Affiliation(s)
- Darran N. Tosh
- 1David Geffen School of Medicine at University of California Los Angeles, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California; ,2The Discipline of Physiology, School of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, ,3Sansom Research Institute, University of South Australia, Adelaide, Australia; and
| | - Qi Fu
- 4Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | | | | | - Isabella C. McMillen
- 3Sansom Research Institute, University of South Australia, Adelaide, Australia; and
| | - Michael G. Ross
- 1David Geffen School of Medicine at University of California Los Angeles, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California;
| | - Robert H. Lane
- 4Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Mina Desai
- 1David Geffen School of Medicine at University of California Los Angeles, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California;
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Kale A, Naphade N, Sapkale S, Kamaraju M, Pillai A, Joshi S, Mahadik S. Reduced folic acid, vitamin B12 and docosahexaenoic acid and increased homocysteine and cortisol in never-medicated schizophrenia patients: implications for altered one-carbon metabolism. Psychiatry Res 2010; 175:47-53. [PMID: 19969375 DOI: 10.1016/j.psychres.2009.01.013] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 01/02/2009] [Accepted: 01/05/2009] [Indexed: 12/14/2022]
Abstract
Abnormal one-carbon metabolism has long been suggested as one of the mechanisms for neuropathology and psychopathology of schizophrenia. Variable levels of components of one-carbon metabolism (folic acid and vitamin B12) and consequent altered levels of homocysteine and phospholipid docosahexaenoic acid (DHA) have been independently reported, mostly in medicated patients. This study examined the simultaneous levels of these key components of one-carbon metabolism and its consequences in unique, medication-naïve first-episode psychotic patients (FEP, n=31) and healthy controls (HC, n=48) matched for confounds such as race, diet and lifestyle to reduce the variability. Significantly lower levels of folate and vitamin B12 in plasma and folate in red blood cells were observed in FEP compared to HC. These reductions paralleled the significant increase in plasma homocysteine and cortisol levels. Significantly reduced levels of membrane DHA were also observed in FEP compared to HC. This study, using a unique cohort, provided a broader mechanism (disturbed folic acid-vitamin B12-DHA balance) of altered one-carbon metabolism and one of its key consequential components, an increased homocysteine level that together with cortisol, can contribute to the neuropathology of psychosis. These data may have important implications for the amelioration of psychopathology in schizophrenia.
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Affiliation(s)
- Anvita Kale
- Department of Nutritional Medicine, Interactive Research School for Health Affairs, Bharati Vidyapeeth University, Pune 411043, India
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Muir WJ, McKechanie AG. Can epigenetics help in the discovery of therapeutics for psychiatric disorders, especially schizophrenia? Expert Opin Drug Discov 2009; 4:621-7. [PMID: 23489155 DOI: 10.1517/17460440902895446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Psychiatric disorders have a heterogeneous biological basis, where environmental factors interplay with non-mendelian genetics to produce complex cognitive/behavioural syndromes such as schizophrenia. Recent findings indicate a proportion of schizophrenia is associated with genomic copy number variation, suggesting that alteration of gene expression levels rather than direct mutation may play a role. Epigenetic mechanisms could be the crucial link between external stimuli and gene expression, influencing schizophrenia risk. These are dynamic reversible systems that offer much promise as targets for future therapies.
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Affiliation(s)
- Walter J Muir
- Reader in Psychiatry University of Edinburgh, Royal Edinburgh Hospital, School of Molecular and Clinical Medicine, Division of Psychiatry, EH10 5HF, Edinburgh, UK
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Plasma homocysteine levels in young male patients in the exacerbation and remission phase of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2008; 32:1921-6. [PMID: 18824063 DOI: 10.1016/j.pnpbp.2008.09.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 09/10/2008] [Accepted: 09/11/2008] [Indexed: 12/16/2022]
Abstract
High levels of homocysteine (Hcy) were suggested to contribute to the pathogenesis of schizophrenia. Recent investigations have shown that treatment with folic acid, vitamin B-12 and pyridoxine are effective in reducing Hcy levels while concomitantly reducing the score of positive and negative symptoms in schizophrenic patients. In addition to the availability of nutrients (mainly folate, vitamins B6 and B12), plasma Hcy concentrations are dependent on complex metabolic regulation that could be disrupted in schizophrenia. This study was designed to test the influence of disease activity on plasma Hcy levels. Plasma Hcy concentrations were measured in male chronic schizophrenic patients with a predominantly positive (SCH (+)) or predominantly negative (SCH (-)) syndrome in schizophrenia immediately upon admission to the hospital (exacerbation phase) and one month later (remission phase). During this period patients received antipsychotic medications without vitamin therapy. The effects of age, duration of illness, folate and B12 concentrations, as well as smoking and coffee consumption habits on the observed changes were evaluated. Age- and sex-matched subjects were included in the control group. In the control group plasma Hcy concentration was 8.75+/-1.84 micromol/L. In the exacerbation phase plasma Hcy concentrations were significantly increased both in SCH (+) (14.91+/-6.19 micromol/L) and SCH (-) groups (12.8+/-3.27 micromol/L). There was no difference in plasma Hcy concentrations between SCH (+) and SCH (-) patients. Serum folate and B12 concentrations were not significantly different in any of the investigated groups of subjects. The plasma Hcy concentrations could not be correlated with age, duration of illness, the score of positive symptoms or the concentration of folate and vitamin B12. A positive correlation was found between plasma Hcy level and score of negative symptoms in both groups of patients. No correlation was found between smoking or coffee consumption habits and plasma Hcy concentrations. All patients exhibited decreased plasma Hcy levels in the remission phase of the illness, with a mean decrease of 2.68+/-1.57 micromol/L. Folate and B12 levels did not differ in the exacerbation and remission phases of the illness. The significant decrease of plasma Hcy levels, without changes in folate and vitamin B12 concentrations in the remission phase of schizophrenia, could indicate an influence of a pathogenetic process involved in schizophrenia on Hcy metabolism.
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Mössner R, Mikova O, Koutsilieri E, Saoud M, Ehlis AC, Müller N, Fallgatter AJ, Riederer P. Consensus paper of the WFSBP Task Force on Biological Markers: biological markers in depression. World J Biol Psychiatry 2007; 8:141-74. [PMID: 17654407 DOI: 10.1080/15622970701263303] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Biological markers for depression are of great interest to aid in elucidating the causes of major depression. We assess currently available biological markers to query their validity for aiding in the diagnosis of major depression. We specifically focus on neurotrophic factors, serotonergic markers, biochemical markers, immunological markers, neuroimaging, neurophysiological findings, and neuropsychological markers. We delineate the most robust biological markers of major depression. These include decreased platelet imipramine binding, decreased 5-HT1A receptor expression, increase of soluble interleukin-2 receptor and interleukin-6 in serum, decreased brain-derived neurotrophic factor in serum, hypocholesterolemia, low blood folate levels, and impaired suppression of the dexamethasone suppression test. To date, however, none of these markers are sufficiently specific to contribute to the diagnosis of major depression. Thus, with regard to new diagnostic manuals such as DSM-V and ICD-11 which are currently assessing whether biological markers may be included in diagnostic criteria, no biological markers for major depression are currently available for inclusion in the diagnostic criteria.
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Affiliation(s)
- Rainald Mössner
- Department of Psychiatry and Psychotherapy, University of Würzburg, Würzburg, Germany
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Haidemenos A, Kontis D, Gazi A, Kallai E, Allin M, Lucia B. Plasma homocysteine, folate and B12 in chronic schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:1289-96. [PMID: 17597277 DOI: 10.1016/j.pnpbp.2007.05.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 05/01/2007] [Accepted: 05/26/2007] [Indexed: 11/26/2022]
Abstract
Elevated plasma levels of the amino acid homocysteine have been associated with schizophrenia, particularly in young male patients. Among other factors, low folate and vitamin B12 levels have been implicated in the increase in homocysteine. In order to investigate this association, we determined plasma homocysteine, folate and B12 levels in 97 (67 males and 30 females) inpatients with chronic schizophrenia and 103 (46 males and 57 females) controls. Patients and controls did not differ in folate or B12 levels, after adjusting for age. Patients with schizophrenia had higher plasma homocysteine than controls (mean=15.42 micromol/l in cases versus 11.54 micromol/l in controls: F(1,195)=17.978; p<0.001). This difference persisted after controlling for folate and B12 concentrations. Both male and female patients had increased plasma homocysteine compared to controls [(males: mean=16.61 micromol/l in cases versus mean=13.72 in controls: F(1,110)=5.54; p=0.020) (females: mean=12.78 micromol/l in cases versus mean=9.79 micromol/l in controls: F(1,84)=13.54; p<0.001)]. When dividing our sample into two age groups (age < and > or =50 years), both young and older females and younger males with schizophrenia had increased plasma homocysteine compared to controls. We therefore suggest that homocysteinemia is a general risk factor for schizophrenia. We further suggest that it is not limited to young male patients and is not necessarily associated with low folate or B12 levels.
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Affiliation(s)
- Alexandros Haidemenos
- 8th Psychiatric Department, Psychiatric Hospital of Attica, 374 Kavalas ave, 12462 Athens, Greece.
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Dealberto MJ. Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both? Med Hypotheses 2007; 68:259-67. [PMID: 17011719 DOI: 10.1016/j.mehy.2006.07.040] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 07/26/2006] [Indexed: 01/08/2023]
Abstract
European researchers have observed that schizophrenia is 3 times more frequent in immigrants than in native-born subjects. This increased risk is even higher in dark-skinned immigrants, and the second generation is more affected than the first one. Immigrant status is an important environmental risk factor not only for schizophrenia but also for other psychoses. The explanations proposed to date have been mainly related to epidemiological biases and psychological reasons, such as racism or social defeat, but no biological hypotheses have been tested so far. This article proposes two biological hypotheses related to changes in sun exposure, changes in diet, and stress associated with immigration, which would explain the increased risk for psychosis associated with immigrant status. (1) Vitamin D insufficiency has been proposed as a risk factor for schizophrenia. The main source of vitamin D is through photosynthesis by sun exposure, and dark skins need more sun exposure to maintain adequate blood levels. Vitamin D insufficiency in adulthood could explain why dark-skinned immigrants develop psychosis when moving to high latitude countries, and its insufficiency during pregnancy could explain why the observed risk is higher in the second generation. (2) The second hypothesis is that of epigenetics, with psychosis resulting from modifications in gene expression caused by changes in diet and/or stress related to immigration. The role of homocysteine and the vitamin B-complex, especially folic acid, in these changes in DNA transcription would vary according to the polymorphism of the methylenetetrahydrofolate reductase gene. The vitamin D insufficiency and epigenetics hypotheses are consistent with yet unexplained findings well known in the epidemiology of schizophrenia, such as the increased risk in the urban environment, the excess of winter births, the excess of schizophrenia births after maternal famine, and the shorter interbirth period before a schizophrenia birth. In order to test these hypotheses, epidemiological studies of psychosis and immigration should include objective measures of skin color, which is predicted to be a more important risk factor than ethnicity. They should measure vitamin D, homocysteine and vitamin B-complex status and assess the polymorphisms of the vitamin D receptors and the methylenetetrahydrofolate reductase gene. If confirmed, these hypotheses would lead to effective and inexpensive preventive measures which would markedly decrease the rates of psychosis and schizophrenia, as well as the burden and stigma of these diseases, and greatly improve the mental health of immigrants.
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Affiliation(s)
- M J Dealberto
- Department of Psychiatry, Ottawa Hospital and University of Ottawa, General Campus, 501 Smyth Road, Ottawa, Ont., Canada K1H 8L6.
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Santos-Rebouças CB, Pimentel MMG. Implication of abnormal epigenetic patterns for human diseases. Eur J Hum Genet 2006; 15:10-7. [PMID: 17047674 DOI: 10.1038/sj.ejhg.5201727] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Significant evidences have brought new insights on the mechanisms by which epigenetic machinery proteins regulate gene expression, leading to a redefinition of chromatin regulation in terms of modification of core histones, DNA methylation, RNA-mediated silencing pathways, action of methylation-dependent sensitive insulators and Polycomb/Trithorax group proteins. Consistent with these fundamental aspects, an increasing number of human pathologies have been found to be associated with aberrant epigenetics regulation, including cancer, mental retardation, neurodegenerative symptoms, imprinting disorders, syndromes involving chromosomal instabilities and a great number of human life-threatening diseases. The possibility of reversing epigenetic marks, in contrast to genetic code, may provide new pharmacological targets for emerging therapeutic intervention.
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Affiliation(s)
- C B Santos-Rebouças
- Department of Cell Biology and Genetics, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Muntjewerff JW, Blom HJ. Aberrant folate status in schizophrenic patients: what is the evidence? Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:1133-9. [PMID: 16111796 DOI: 10.1016/j.pnpbp.2005.06.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/17/2005] [Indexed: 11/28/2022]
Abstract
A vast amount of case reports, open studies and, to a lesser extent, case-control studies have been published on the topic of psychopathology and folate deficiency. These studies reported a high incidence of serum folate deficiency in patients with various psychiatric disorders. Folate deficiency seems to be a particular consistent finding in depressive patients. The evidence for an association between aberrant folate status and schizophrenia seems less convincing. The lack of stringent methodology such as inclusion of age- and sex-matched controls was thought to be the main reason for the inconclusive results. The purpose of this article is to review the published case-control studies that provide data on folate levels in the population of patients with schizophrenia. Data extracted from these studies comprised methodological design, clinical characteristics and folate measurements. We found that none of the 7 case-control studies included in this review (in total 325 cases and 560 control subjects) explicitly reported on all critical factors in the assessment of folate. In addition, only three studies found lower plasma folate levels more frequently in patients with schizophrenia compared to controls. Further research on this topic is required to clarify the relationship between folate status and schizophrenia and should avoid the methodological pitfalls mentioned in this review. In addition, research should also focus on polymorphisms of genes related to folate metabolism.
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Affiliation(s)
- Jan-Willem Muntjewerff
- GGz Nijmegen, Mental Health Institute Nijmegen, P.O. Box 7049, 6503 GM Nijmegen, The Netherlands.
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Abdolmaleky HM, Smith CL, Faraone SV, Shafa R, Stone W, Glatt SJ, Tsuang MT. Methylomics in psychiatry: Modulation of gene-environment interactions may be through DNA methylation. Am J Med Genet B Neuropsychiatr Genet 2004; 127B:51-9. [PMID: 15108180 DOI: 10.1002/ajmg.b.20142] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fine-tuning of neuronal connections during development is regulated through environmental interactions. Some fine-tuning occurs through changes in gene expression and/or epigenetic gene-specific DNA methylation states. DNA methylation occurs by transfer of a methyl group from S-adenosyl methionine to cytosine residues in the dinucleotide sequence CpG. Although CpG sequences spread throughout the genome are usually heavily methylated, those occurring in CpG islands in the promoter regions of genes are less methylated. In most cases, the extent of DNA methylation correlates with the extent of gene inactivation. Other known epigenetic mechanisms include histone deacetylation and chromatin remodeling, RNA inhibition, RNA modification, and DNA rearrangement. Exposure memory expressed as epigenetic DNA modifications allows genomic plasticity and short-term adaptation of each generation to their environment. Environmental factors that affect DNA methylation include diet, proteins, drugs, and hormones. Induced methylation changes may produce altered gene response upon subsequent hormonal stimulation. The gene-specific DNA methylation state may be preserved upon transmission through mitosis and meiosis. An increasing amount of data implicates a role for DNA methylation in multi-factorial psychiatric disorders. For example, L-methionine treatment can exacerbate psychosis; while valproate, a drug producing hypomethylated DNA, reduces such symptoms. Hypermethylation of the promoter region of the RELN gene correlates with reduced gene expression. This gene's protein Reelin, which is necessary for neuronal migration and synaptogenesis, is reduced in schizophrenia and bipolar disorder, suggesting hypermethylation of the promoter region in these disorders. Some evidence implicates methylation of the promoter regions of the DRD2 and HTR2A genes in schizophrenia and mood disorders as well. DNA methylation usually increases with age, although hypomethylation of the promoter region of the amyloid A4 precursor gene during aging may play a role in Alzheimer's disease. More studies are needed to define the role of methylomics and other epigenetic phenomena in the nervous system.
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Affiliation(s)
- Hamid Mostafavi Abdolmaleky
- Department of Psychiatry, Harvard Medical School at Massachusetts Mental Health Center, Boston, Massachusetts 02115, USA
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Muntjewerff JW, van der Put N, Eskes T, Ellenbroek B, Steegers E, Blom H, Zitman F. Homocysteine metabolism and B-vitamins in schizophrenic patients: low plasma folate as a possible independent risk factor for schizophrenia. Psychiatry Res 2003; 121:1-9. [PMID: 14572619 DOI: 10.1016/s0165-1781(03)00200-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two apparently unrelated disorders, neural tube defects (NTD) and schizophrenia showed increased risks in birth cohorts exposed to famine during early gestation. NTD is associated with impaired folate metabolism. We investigated whether schizophrenia is also linked with a dysfunctional folate metabolism. In addition to the prevalence of the 677C-->T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, we compared plasma and red blood cell (RBC) folate, vitamin B6, vitamin B12, and homocysteine (Hcy) concentrations of 35 schizophrenic patients with those of 104 unrelated controls. Schizophrenic patients had significantly lower plasma folate concentrations after adjustment for Hcy levels, and elevated RBC folate levels compared to controls. Vitamin B6, vitamin B12, and Hcy levels did not differ from control values. Plasma folate levels below the 10th percentile of controls were associated with an approximate 4-7-fold (before and after adjustment of folate levels for Hcy, respectively) risk of having schizophrenia. In addition, a significant dose-response relation between plasma folate concentrations and risk for schizophrenia suggested a protective effect by high plasma folate concentrations. Elevated Hcy levels and, in line with this finding, homozygosity for the 677C-->T mutation in the MTHFR gene were not associated with an increased risk for schizophrenia. Evidence is presented suggesting that folate metabolism is disturbed in schizophrenic patients, independently of Hcy.
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Affiliation(s)
- Jan-Willem Muntjewerff
- GGz Nijmegen, Mental Health Institute, P.O. Box 7049, 6503 GM Nijmegen, The Netherlands.
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Herrán A, García-Unzueta MT, Amado JA, de La Maza MT, Alvarez C, Vázquez-Barquero JL. Effects of long-term treatment with antipsychotics on serum leptin levels. Br J Psychiatry 2001; 179:59-62. [PMID: 11435270 DOI: 10.1192/bjp.179.1.59] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Abnormal regulation of the adipocyte-derived hormone leptin could play a role in body weight gain induced by antipsychotics. AIMS To study the effects of long-term antipsychotic treatment on leptin levels in patients with schizophrenia. METHOD Serum leptin levels were determined in 59 out-patients with chronic schizophrenia and in the same number of healthy subjects controlled by gender, age and body mass index. RESULTS Leptin levels did not differ between patients and controls. Leptin levels in patients with schizophrenia correlated with weight gain, even after controlling for current weight, but did not show any association with clinical variables. Antipsychotic class tended to exert different effects over leptin levels (among atypicals, olanzapine induced a greater increase). CONCLUSIONS Elevation of leptin levels induced by chronic antipsychotic treatment can be attributed to weight gain, but other mechanisms could be involved.
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Affiliation(s)
- A Herrán
- Clinical and Social Psychiatry Research Unit, Department of Psychiatry, University Hospital Marqués de Valdecilla, Santander, Spain.
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