Elevated homocysteine level in first-episode schizophrenia patients--the relevance of family history of schizophrenia and lifetime diagnosis of cannabis abuse

Blood-based biomarkers in mild behavioral impairment: an updated overview

Identifying individuals at-risk for dementia is one of the critical objectives of current research efforts, highlighting the need for simple, cost-effective, and minimally invasive biomarkers. Mild behavioral impairment (MBI), characterized by the emergence of persistent neuropsychiatric manifestations in older adults, has attracted increasing attention as a potential early indicator of cognitive decline and dementia. A growing number of studies have recently begun to explore the relationship between MBI and several blood-based biomarkers associated with Alzheimer's disease (AD) pathology, neurodegeneration, as well as systemic metabolic and inflammatory dysregulation. In this context, MBI has been associated with lower plasma Aβ42/Αβ40 ratio, higher plasma phosphorylated tau at threonine 181 (p-tau181), increased neurofilament light chain (NfL) levels, as well as disturbances in metabolic markers, including homocysteine, insulin and ferritin, suggesting a multifaceted neurobiological basis for this syndrome. These findings offer insights into the underlying pathophysiology of MBI, and connection between neuropsychiatric symptoms and progression of AD. In this narrative review, we aim to summarize and critically discuss the emerging literature evidence linking MBI to blood-based biomarkers, hoping to shed more light on MBI's pathophysiology, its connection to AD-related neurobiology, as well as its potential practical utility for predicting cognitive impairment, guiding early interventions and managing the risk for dementia.

Hyperhomocysteinemia is associated with the risk of venous thromboembolism in patients with mental illness: a case-control study

Objective

The risk of venous thromboembolism in patients with mental illness has been insufficiently addressed. This study aimed to assess the correlation between hyperhomocysteinemia and venous thromboembolism prevalence among this population.

Methods

Patients with a diagnosis of mental illness and concurrent venous thromboembolism, admitted to Sir Run Run Shaw Hospital at Zhejiang University School of Medicine between January 2014 and December 2021, were included in the venous thromboembolism group. The control group, approximately twice the size, comprised individuals with mental illness but without venous thromboembolism. Basic clinical data were gathered for both cohorts.

Results

In psychiatric patients, elevated D-dimer levels(OR=5.60,95% CI 3.28-10.00), hyperhomocysteinemia (OR=2.37,95% CI 1.10-5.14), and hyperprolactinemia(OR= 2.68,95% CI 1.12-6.42)were significant risk factors for venous thromboembolism. According to further subgroup analyses, hyperhomocysteinemia is a significant risk factor associated with pulmonary embolism, with an OR of 5.08 (95% CI 1.20-21.48). An interaction effect between gender and homocysteine level was found, with a p-interaction of 0.022. A subsequent analysis confirmed the association between hyperhomocysteinemia and venous thromboembolism in female psychiatric patients, with an OR of 3.34 (95% CI 1.68-6.65), indicating that hyperhomocysteinemia is a significant risk factor for venous thromboembolism in women.

Conclusion

Patients with psychiatric disorders were found to have an elevated risk of venous thromboembolism, which was associated with increased levels of D-dimer, hyperprolactinemia, and hyperhomocysteinemia. A strong correlation between hyperhomocysteinemia and pulmonary embolism was identified in patients with mental illnesses. Furthermore, the study revealed that female psychiatric patients with hyperhomocysteinemia constituted a high-risk group for venous thromboembolism. This finding holds significant clinical implications, suggesting that early preventative measures could be implemented for this high-risk population to reduce the incidence of thromboembolic events during hospitalization for psychiatric patients.

Association of homocysteine with white matter dysconnectivity in schizophrenia

Several studies have shown white matter (WM) dysconnectivity in people with schizophrenia (SZ). However, the underlying mechanism remains unclear. We investigated the relationship between plasma homocysteine (Hcy) levels and WM microstructure in people with SZ using diffusion tensor imaging (DTI). Fifty-three people with SZ and 83 healthy controls (HC) were included in this retrospective observational study. Tract-Based Spatial Statistics (TBSS) were used to evaluate group differences in WM microstructure. A significant negative correlation between plasma Hcy levels and WM microstructural disruption was noted in the SZ group (Spearman's ρ = -.330, P = 0.016) but not in the HC group (Spearman's ρ = .041, P = 0.712). These results suggest that increased Hcy may be associated with WM dysconnectivity in SZ, and the interaction between Hcy and WM dysconnectivity could be a potential mechanism of the pathophysiology of SZ. Further, longitudinal studies are required to investigate whether high Hcy levels subsequently cause WM microstructural disruption in people with SZ.

Sulfur-containing amino acids and risk of schizophrenia

BACKGROUND

Schizophrenia is a chronic and complex severe psychiatric disorder. Male and female are different in their risks for schizophrenia for the biologic and sociocultural reasons. Homocysteine (Hcy), Cysteine (Cys), and methionine (Met) play important roles in metabolism, and the three amino acids may also be involved in pathogenesis of schizophrenia.

OBJECTIVE

This study aimed to test the associations between sulfur-containing amino acid blood levels and risk of schizophrenia, evaluating the different risk in male and female.

METHODS

We organized a case-control study on 876 individuals with schizophrenia and 913 age- and sex-matched healthy subjects as control group. The concentrations of Hcy, Cys and Met were measured by liquid chromatography-tandem mass spectrometry technology. Subsequently, restricted cubic spline was applied to explore full-range associations of these amino acids with schizophrenia. Interactions between levels of the three amino acids and sex on additive scale were also tested.

RESULTS

Hcy levels at ≤29 μmol/L were associated with sharply increased risk of schizophrenia, inversely, Met was associated with sharply decreased risk of schizophrenia at levels ≤22 μmol/L. Increased Cys levels were associated with decreased risk of schizophrenia. Almost inverse associations were observed between Cys/Hcy and Met/Hcy ratios and schizophrenia. Significant synergistic interactions between levels of all the three amino acids and sex were discovered on an additive scale.

CONCLUSIONS

Our study suggests a close association between sulfur-containing amino acids and schizophrenia with different risk in male and female. Future studies are demanded to clarify the pathogenic role of Hcy, Cys and Met in schizophrenia.

Association of serum homocysteine levels with intestinal flora and cognitive function in schizophrenia

Some studies have indicated that elevated homocysteine (Hcy) levels and intestinal flora may be involved in schizophrenia (SZ) cognition pathophysiology. This study was the first to investigate the association among Hcy, intestinal flora and schizophrenia cognition. Here, 140 individuals were divided into two groups: SZ patients (N = 68) and healthy controls (HCs, N = 72). Participant data on serum Hcy levels, intestinal flora and cognitive function evaluation using the MATRICS Consensus Cognitive Battery (MCCB) were collected. Clinical symptoms of patients were evaluated using the Positive and Negative Syndrome Scale. Serum Hcy levels and the incidence of hyperhomocysteinaemia were considerably increased in SZ patients compared with HCs. Hcy levels were significantly negatively associated with verbal learning index scores (r = -0.425, p < 0.001) but positively associated with Eubacterium (r = 0.32, p = 0.007), Lactobacillus (r = 0.32, p = 0.008), Corynebacterium (r = 0.26, p = 0.035), Mogibacterium (r = 0.31, p = 0.01), and Bulleidia (r = 0.31, p = 0.01) in SZ patients. Our findings suggest that serum Hcy levels are associated with cognitive function and intestinal flora in SZ patients. However, the mechanism of the interaction between Hcy and intestinal flora and its effects on cognitive function in SZ patients requires further investigation.

Abnormalities in one-carbon metabolism in young patients with psychosis

INTRODUCTION

Folates, the main actors in one-carbon (C1) metabolism, are involved in synthesising monoamines and maintaining genomic stability. Previous studies support the association between C1 metabolism and schizophrenia. The main purpose of this study was to assess the prevalence of plasma folate, and/or vitamin B12 deficiencies and hyperhomocysteinemia in young patients with psychotic disorders.

METHODS

We included young inpatients (15-30 years old) with psychosis between 2014 and 2017 from Sainte-Anne Hospital in Paris. Plasma folate, vitamin B12 deficiency and homocysteinemia dosages were done at admission. Clinical data were extracted retrospectively, and patients diagnosed with a first-episode psychosis (FEP), schizophrenia, schizoaffective disorder, or persistent delusional disorder were retained for the analysis.

RESULTS

Among the 334 inpatients, 188 (56%) had C1 dosages available (135 males; 53 females). From the 188 patients, 32% had a C1 abnormality. This abnormality reached 38% of FEP patients. The most frequent abnormality was folate deficiency: 21% of all patients and 27% of FEP. Lower levels of folates were found in males compared to females (p = 0.02) and were correlated with more severe disorder, as assessed by Clinical Global Impression - Severity (CGI-S; p = 0.009). Antipsychotic dosage was positively associated with B12 levels (p = 0.013) and negatively with homocysteinemia (p = 0.034).

CONCLUSION

One-carbon metabolism anomalies in young patients with psychotic disorders are highly prevalent, reaching almost half of the patients with FEP. Potential protective effects from females and antipsychotics have emerged. These results spotlight the need for new therapeutic prospects, such as folate supplementation, to achieve personalised medical approaches to the early stages of psychotic disorders.

Prevalence of metabolic syndrome and related factors in a large sample of antipsychotic naïve patients with first-episode psychosis: Baseline results from the PAFIP cohort

BACKGROUND

Few investigations have been carried out on metabolic syndrome in antipsychotic- naïve patients with schizophrenia.

METHODS

Our primary objective was to compare the prevalence of Metabolic Syndrome (MetS), as defined by the National Cholesterol Education Program, Adult Treatment Panel III in 2001 (NCEP-ATP III), between a Spanish cohort of 303 drug-naïve patients with a first episode of psychosis (FEP) without any previous cardiovascular condition, and 153 healthy individuals.

RESULTS

Participants included 303 patients with FEP (M:F 53:46) and 153 control subjects (M:F 56:43). The mean and standard deviation ages were 31(9.38) and 29 (7.57) years in the study and control groups respectively (F = 4.09; p = 0.93). We found that the prevalence of MetS in drug-naïve patients with FEP (5.6 %) was similar to the prevalence of MetS in age-sex matched controls (5.12 %). However, 60.7 % of patients with FEP met at least one of the five MetS components, while among the control subjects only 36.5 % met at least one component. Additionally, we found that other factors not included among the operational definition of MetS, but still important in cardiovascular risk, were also altered.

CONCLUSION

FEP patients have a greater risk of presenting at least one altered MetS component than healthy controls which could indicate the need of development of screening methods detecting cardiovascular risk. Likewise, gender differences in metabolic components such as waist circumference, which is a predictor of cardiovascular events have been found. Similarly, research should focus on metabolic risk predictors that include not only MetS, but also specific parameters for the early psychosis population.

Investigating Associations Between Depressive Symptoms and Anti-/Pro-Inflammatory Nutrients in an Elderly Population in Northern China: A Bayesian Kernel Machine Regression Approach

Backgroud

The potential for dietary inflammation has been shown to be associated with a variety of chronic diseases. The relationship between the potential for dietary inflammation and depression in the elderly is unclear.

Objective

This study aimed to exam the relationship between different nutrients and the risk of depression symptoms in the elderly.

Methods

In total, 1865 elderly in northern China were investigated at baseline from 2018 to 2019 and followed up in 2020. We measured the baseline intake of 22 nutrients and used Least Absolute Shrinkage and Selection Operator(LASSO) regression analysis and Bayesian Kernel Machine Regression (BKMR) to explore the association between exposure to a variety of nutrients with different inflammatory potentials and the risk of depressive symptoms.

Results

A total of 447 individuals (24.0%) were diagnosed with depressive symptoms. Through the lasso regression model, it was found that 11 nutrients are significantly related to the risk of depressive symptoms, of which 6 nutrients are pro-inflammatory nutrients (inflammation effect score>0), and 5 are anti-inflammatory nutrients (inflammation effect score<0). We incorporated the inflammatory effect scores of 11 nutrients into the BKMR model at the same time, and found that the overall inflammatory effect of 11 nutrients increased with the increase of total inflammatory scores, suggesting that the overall effect was pro-inflammatory. BKMR subgroup analysis shows that whether in the pro-inflammatory nutrient group or the anti-inflammatory nutrient group, multiple nutrients have a significant combined effect on depressive symptoms. By comparing the overall and group effects, we found that the inflammatory effects of the pro-inflammatory diet and the anti-inflammatory diet in the study’s diet are offset by each other (P<0.005).

Conclusion

We determined the combined effect of multiple nutrients of different inflammatory potential classifications on depressive symptoms in the elderly.

When should a psychiatrist remember to test homocysteine levels? - a literature review

Introduction: Homocysteine is an endogenous sulfur amino acid, formed as a result of biochemical changes in methionine. The normal concentration of homocysteine in healthy people is within the range of 5 - 15 µmol / l, and values above 15 µmol / l are referred to as hyperhomocysteinemia. Moreover, it has been shown that the level of homocysteine may be associated with the occurrence of mental disorders. The aim of this article was to search for a relationship between the level of this amino acid and the incidence and prognosis of bipolar disorder, depression, anxiety disorders, schizophrenia or Alzheimer’s disease.

Material and method: For the review of the literature, available articles from the PubMed database and Google Scholar were used under the following keywords: homocysteine, depression, bipolar disorder, schizophrenia, Alzheimer’s disease in the period from 1992 to 2021.

Results: The research conducted so far shows that there is a significant correlation between elevated levels of homocysteine and the above-mentioned mental disorders.

Conclusion: In order to prevent the consequences of the increased level of homocysteine, its concentration in blood serum should be monitored periodically and appropriate treatment should be implemented in case of abnormal results. It is important to educate patients about the consequences of hyperhomocysteinemia i.a. atherosclerosis, stroke, ischemic heart disease, osteoporosis, neural tube defects, mental disorders and neurodegenerative diseases. It should be also established a strategy to lower the level of this amino acid through lifestyle changes, as well as the supply of folic acid, vitamins B12, B6, B2, N-acetylcysteine and betaine.

Treatment-resistant schizophrenia: focus on the transsulfuration pathway

Treatment-resistant schizophrenia (TRS) is a severe form of schizophrenia. The severity of illness is positively related to homocysteine levels, with high homocysteine levels due to the low activity of the transsulfuration pathway, which metabolizes homocysteine in synthesizing L-cysteine. Glutathione levels are low in schizophrenia, which indicates shortages of L-cysteine and low activity of the transsulfuration pathway. Hydrogen sulfide (H2S) levels are low in schizophrenia. H2S is synthesized by cystathionine β-synthase and cystathionine γ-lyase, which are the two enzymes in the transsulfuration pathway. Iron-sulfur proteins obtain sulfur from L-cysteine. The oxidative phosphorylation (OXPHOS) pathway has various iron-sulfur proteins. With low levels of L-cysteine, iron-sulfur cluster formation will be dysregulated leading to deficits in OXPHOS in schizophrenia. Molybdenum cofactor (MoCo) synthesis requires sulfur, which is obtained from L-cysteine. With low levels of MoCo synthesis, molybdenum-dependent sulfite oxidase (SUOX) will not be synthesized at appropriate levels. SUOX detoxifies sulfite from sulfur-containing amino acids. If sulfites are not detoxified, there can be sulfite toxicity. The transsulfuration pathway metabolizes selenomethionine, whereby selenium from selenomethionine can be used for selenoprotein synthesis. The low activity of the transsulfuration pathway decreases selenoprotein synthesis. Glutathione peroxidase (GPX), with various GPXs being selenoprotein, is low in schizophrenia. The dysregulations of selenoproteins would lead to oxidant stress, which would increase the methylation of genes and histones leading to epigenetic changes in TRS. An add-on treatment to mainline antipsychotics is proposed for TRS that targets the dysregulations of the transsulfuration pathway and the dysregulations of other pathways stemming from the transsulfuration pathway being dysregulated.

Combined glyoxalase 1 dysfunction and vitamin B6 deficiency in a schizophrenia model system causes mitochondrial dysfunction in the prefrontal cortex

Methylglyoxal (MG) is a reactive and cytotoxic α-dicarbonyl byproduct of glycolysis. Our bodies have several bio-defense systems to detoxify MG, including an enzymatic system by glyoxalase (GLO) 1 and GLO2. We identified a subtype of schizophrenia patients with novel mutations in the GLO1 gene that results in reductions of enzymatic activity. Moreover, we found that vitamin B6 (VB6) levels in peripheral blood of the schizophrenia patients with GLO1 dysfunction are significantly lower than that of healthy controls. However, the effects of GLO1 dysfunction and VB6 deficiency on the pathophysiology of schizophrenia remains poorly understood. Here, we generated a novel mouse model for this subgroup of schizophrenia patients by feeding Glo1 knockout mice VB6-deficent diets (KO/VB6(−)) and evaluated the combined effects of GLO1 dysfunction and VB6 deficiency on brain function. KO/VB6(−) mice accumulated homocysteine in plasma and MG in the prefrontal cortex (PFC), hippocampus, and striatum, and displayed behavioral deficits, such as impairments of social interaction and cognitive memory and a sensorimotor deficit in the prepulse inhibition test. Furthermore, we found aberrant gene expression related to mitochondria function in the PFC of the KO/VB6(−) mice by RNA-sequencing and weighted gene co-expression network analysis (WGCNA). Finally, we demonstrated abnormal mitochondrial respiratory function and subsequently enhanced oxidative stress in the PFC of KO/VB6(−) mice in the PFC. These findings suggest that the combination of GLO1 dysfunction and VB6 deficiency may cause the observed behavioral deficits via mitochondrial dysfunction and oxidative stress in the PFC.

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A combination of Glo1 KO and VB6 deficiency induces MG accumulation in the brain.

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Glo1 KO/VB6(−) mice exhibit schizophrenia-like behavioral deficits.

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Gene expression related to mitochondria is impaired in the PFC of the Glo1 KO/VB6(−).

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Mitochondria in the PFC of the Glo1 KO/VB6(−) mice show respiratory dysfunction.

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Oxidative stress is enhanced in the PFC of the Glo1 KO/VB6(−).

Prevalence and clinical demography of hyperhomocysteinemia in Han Chinese patients with schizophrenia

Previous studies have shown that high homocysteine worsens the occurrence, symptoms, and prognosis of patients with schizophrenia. The purpose of this study was to evaluate the prevalence, clinical correlation, and demographic characteristics of hyperhomocysteinemia in Han Chinese schizophrenia patients. In this study, we enrolled 330 schizophrenia patients and 190 healthy controls. Positive and Negative Syndrome Scale (PANSS) was used to evaluate the psychiatric symptoms of patients with schizophrenia. The plasma homocysteine level was measured by the enzyme cycle method and the concentration of homocysteine > 15 μmol/L was defined as hyperhomocysteinemia. The prevalence of hyperhomocysteinemia in Han Chinese schizophrenia patients and healthy controls was 55.05% and 26.98%, respectively. Schizophrenia patients with hyperhomocysteinemia had more male proportion, older age, higher smoking rate, lower HDL level, higher PANSS total score, and higher negative factor than those patients without hyperhomocysteinemia. Binary logical regression result showed that gender and age were the independent risk factors of hyperhomocysteinemia. Han Chinese patients with schizophrenia had high prevalence hyperhomocysteinemia than healthy controls, and elderly male patients have a higher risk of hyperhomocysteinemia. This study was registered in the China Clinical Trial Registration Center (chiCTR 1800017044).

Gut microbiota-derived vitamins - underrated powers of a multipotent ally in psychiatric health and disease

Despite the well-established roles of B-vitamins and their deficiencies in health and disease, there is growing evidence indicating a key role of those nutrients in functions of the central nervous system and in psychopathology. Clinical data indicate the substantial role of B-vitamins in various psychiatric disorders, including major depression, bipolar disorder, schizophrenia, autism, and dementia, including Alzheimer's and Parkinson's diseases. As enzymatic cofactors, B-vitamins are involved in many physiological processes such as the metabolism of glucose, fatty acids and amino acids, metabolism of tryptophan in the kynurenine pathway, homocysteine metabolism, synthesis and metabolism of various neurotransmitters and neurohormones including serotonin, dopamine, adrenaline, acetylcholine, GABA, glutamate, D-serine, glycine, histamine and melatonin. Those vitamins are highly involved in brain energetic metabolism and respiration at the cellular level. They have a broad range of anti-inflammatory, immunomodulatory, antioxidant and neuroprotective properties. Furthermore, some of those vitamins are involved in the regulation of permeability of the intestinal and blood-brain barriers. Despite the fact that a substantial amount of the above vitamins is acquired from various dietary sources, deficiencies are not uncommon, and it is estimated that micronutrient deficiencies affect about two billion people worldwide. The majority of gut-resident microbes and the broad range of bacteria available in fermented food, express genetic machinery enabling the synthesis and metabolism of B-vitamins and, consequently, intestinal microbiota and fermented food rich in probiotic bacteria are essential sources of B-vitamins for humans. All in all, there is growing evidence that intestinal bacteria-derived vitamins play a significant role in physiology and that dysregulation of the "microbiota-vitamins frontier" is related to various disorders. In this review, we will discuss the role of vitamins in mental health and explore the perspectives and potential of how gut microbiota-derived vitamins could contribute to mental health and psychiatric treatment.

Involvements of Hyperhomocysteinemia in Neurological Disorders

Homocysteine (HCY), a physiological amino acid formed when proteins break down, leads to a pathological condition called hyperhomocysteinemia (HHCY), when it is over a definite limit. It is well known that an increase in HCY levels in blood, can contribute to arterial damage and several cardiovascular disease, but the knowledge about the relationship between HCY and brain disorders is very poor. Recent studies demonstrated that an alteration in HCY metabolism or a deficiency in folate or vitamin B12 can cause altered methylation and/or redox potentials, that leads to a modification on calcium influx in cells, or into an accumulation in amyloid and/or tau protein involving a cascade of events that culminate in apoptosis, and, in the worst conditions, neuronal death. The present review will thus summarize how much is known about the possible role of HHCY in neurodegenerative disease.

Early-Onset Schizophrenia: A Special Phenotype of the Disease Characterized by Increased MTHFR Polymorphisms and Aggravating Symptoms

BACKGROUND

Patients with early-onset schizophrenia usually exhibit more severe symptoms, revealing a potentially distinctive disease phenotype. Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate conversion and methylation modification associated with the disease. We aimed to investigate the potential effects of MTHFR polymorphisms and related methylation patterns in patients with early-onset schizophrenia, which implies special phenotypes of schizophrenia.

METHODS

In 177 patients with schizophrenia, MTHFR polymorphism at three sites (C677T, A1298C, and G1793A) and the Positive and Negative Syndrome Scale (PANSS) were tested. Differential methylation positions (DMPs) and enrichment of genes and related pathways were analyzed by testing the genomic methylation level. Catechol-O-methyltransferase (COMT), solute carrier family 6 member 4 (SLC6A4), neuregulin1 (NRG1), and brain-derived neurotrophic factor (BDNF) were selected to evaluate the methylation levels of specific CpG regions by pyrosequencing.

RESULTS

Higher levels of symptom severity and MTHFR polymorphisms and lower levels of global DNA methylation in patients with early-onset schizophrenia were observed in this study. SLC6A4 was hypermethylated, and BDNF was hypomethylated in specific regions of patients with early-onset schizophrenia.

CONCLUSION

Aggravating symptoms, increased MTHFR polymorphisms, and reduced genomic methylation levels may be characteristics and underlying mechanisms of early-onset schizophrenia, which implies a special disease phenotype. Beyond that, specific genes and biological pathways may imply the potential phenotype of schizophrenia.

Association between serum folate levels and schizophrenia based on sex

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.

Homocysteine, but not MTHFR gene polymorphism, influences depressive symptoms in patients with schizophrenia

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme of folate metabolism in the process of one-carbon cycle and its deficiency results in elevated homocysteine concentration. In this study, we hypothesized that MTHFR C677T polymorphism and homocysteine concentration may play important roles in the development of depressive symptoms in schizophrenia.

METHODS

We recruited 715 patients with stable schizophrenia, and among them, 197 schizophrenia patients under olanzapine monotherapy were enrolled for homocysteine concentration analysis. The Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) were employed to evaluate psychiatric and depressive symptoms.

RESULTS

When the 715 schizophrenia patients were evaluated by CDSS, 326 individuals (45.6%) had depressive symptoms. No significant differences were observed in C677T genotype and allele distributions between the schizophrenia with or without depression groups. Schizophrenia patients with depression have higher levels of homocysteine than those without depression (P = 0.019). There was a positive correlation between the homocysteine levels and CDSS score (r = 0.22, P = 0.002).

CONCLUSION

Our findings suggested that higher levels of homocysteine may be a risk factor for the development of depressive symptoms in schizophrenia patients.

Homocysteine as a peripheral biomarker in bipolar disorder: A meta-analysis

Background:

Bipolar disorder (BD) is a psychiatric disorder with an uncertain aetiology. Recently, special attention has been given to homocysteine (Hcy), as it has been suggested that alterations in 1-carbon metabolism might be implicated in diverse psychiatric disorders. However, there is uncertainty regarding possible alterations in peripheral Hcy levels in BD.

Methods:

This study comprises a meta-analysis comparing serum and plasma Hcy levels in persons with BD and healthy controls. We conducted a systematic search for all eligible English and non-English peer-reviewed articles.

Results:

Nine cross-sectional studies were included in the meta-analyses, providing data on 1547 participants. Random-effects meta-analysis showed that serum and plasma levels of Hcy were increased in subjects with BD in either mania or euthymia when compared to healthy controls, with a large effect size in the mania group (g= 0.98, 95% CI: 0.8–1.17,P< 0.001,n= 495) and a small effect in the euthymia group (g= 0.3, 95% CI: 0.11–0.48,P= 0.002,n= 1052).

Conclusions:

Our meta-analysis provides evidence that Hcy levels are elevated in persons with BD during mania and euthymia. Peripheral Hcy could be considered as a potential biomarker in BD, both of trait (since it is increased in euthymia), and also of state (since its increase is more accentuated in mania). Longitudinal studies are needed to clarify the relationship between bipolar disorder and Hcy, as well as the usefulness of peripheral Hcy as both a trait and state biomarker in BD.

Regulation of inflammatory pathways in schizophrenia: A comparative study with bipolar disorder and healthy controls

Background

Immune-inflammatory processes have been implicated in schizophrenia (SCH), but their specificity is not clear.

Main aim

To identify potential differential intra-/intercellular biochemical pathways controlling immune-inflammatory response and their oxidative-nitrosative impact on SCH patients, compared with bipolar disorder (BD) patients and healthy controls (HC).

Methods

Cross-sectional, naturalistic study of a cohort of SCH patients (n=123) and their controls [BD (n=102) and HC (n=80)].

Statistical analysis

ANCOVA (or Quade test) controlling for age and gender when comparing the three groups, and controlling for age, gender, length of illness, cigarettes per day, and body mass index (BMI) when comparing SCH and BD.

Results

Pro-inflammatory biomarkers: Expression of COX-1 was statistically higher in SCH and BD than HC (P<0.0001; P<0.0001); NFκB and PGE2 were statistically higher in SCH compared with BD (P=0.001; P<0.0001) and HC (P=0.003; P<0.0001); NLRP3 was higher in BD than HC (P=0.005); and CPR showed a gradient among the three groups. Anti-inflammatory biomarkers: BD patients had lower PPARγ and higher 15d-PGJ2 levels than SCH (P=0.005; P=0.008) and HC (P=0.001; P=0.001). Differences between SCH and BD: previous markers of SCH (NFκB and PGE2) and BD (PPARγ and 15d-PGJ2) remained statistically significant and, interestingly, iNOS and COX-2 (pro-inflammatory biomarkers) levels were statistically higher in SCH than BD (P=0.019; P=0.040).

Conclusions

This study suggests a specific immune-inflammatory biomarker pattern for established SCH (NFκB, PGE2, iNOS, and COX-2) that differentiates it from BD and HC. In future, their pharmacological modulation may constitute a promising therapeutic target.

Are plasma 25-hydroxyvitamin D and retinol levels and one-carbon metabolism related to metabolic syndrome in patients with a severe mental disorder?

There is a scarcity of studies assessing the influence of biomarkers in metabolic syndrome in psychiatric patients. Our aim was to correlate serum or plasma levels of 25-hydroxyvitamin D (25-OH-VD), retinol, vitamin B12 (VB12), folate and homocysteine (Hcy), with the metabolic status, in a sample of 289 outpatients with Schizophrenia or Bipolar Disorder. Logistic regression and multiple linear regressions were performed to assess the ability of biomarkers to predict the presence of MetS, the number of risk factors for MetS, and insulin resistance indexes (HOMA and QUICKI). Regarding the association between biomarkers and the QUICKI index, the model explained 6.8% of the variance, with folate and 25-OH-VD levels contributing significantly to the model. The model predicting the number of MetS risk factors was significant and explained 21.7% of the variance, being 25-OH-VD and retinol the statistically significant factors. As for the impact of biomarkers on MetS, the model was statistically significant, being 25-OH-VD and retinol levels the significant factors.  We report for the first time an association between MetS and both low 25-OH-VD and high retinol concentrations. Inflammation-related biomarkers may help identify patients with a high risk of MetS who might benefit from healthy lifestyle counselling and early intervention.

Decreased Serum Oxytocin and Increased Homocysteine in First-Episode Schizophrenia Patients

Schizophrenia (SZ) is a debilitating and heterogeneous disease. We hypothesized that the oxytocin (OXT) system, inflammation and one-carbon metabolism would have a link with SZ. In this study, serum OXT, OXT receptor (OXTR), interleukin-6 (IL-6), high sensitivity CRP (hsCRP) and homocysteine (Hcy) levels were measured in 52 first-episode schizophrenia (FES) patients and 41 healthy controls (HC) from the Second Xiangya Hospital of Central South University. Meanwhile, the mRNA expressions of OXT and OXTR genes were determined by real-time quantitative PCR. Serum OXT and OXTR levels were significantly lower in FES patients (518.96 ± 22.22 and 174.60 ± 17.11 pg/ml) than the HC group (711.58 ± 40.57 and 252.15 ± 20.62 pg/ml). Serum IL-6 and hsCRP levels showed no difference between the two groups (1.82 ± 0.30 vs. 1.69 ± 0.36 pg/ml, 0.66 (0.22, 1.07) vs. 0.31 (0.13, 0.91) mg/L), but serum Hcy levels were significantly higher in FES patients (20.18 ± 1.83 vs. 15.24 ± 0.82 μmol/ml). The FES patients (0.27 ± 0.02 and 0.20 ± 0.02) have relatively higher mRNA expressions of OXT and OXTR genes than the HC group (0.16 ± 0.01 and 0.14 ± 0.01). In summary, our results suggested the possible function of the OXT system and Hcy in the pathogenesis of SZ.

Nutritional Deficiencies and Clinical Correlates in First-Episode Psychosis: A Systematic Review and Meta-analysis

Objective

Diet is increasingly recognized as a potentially modifiable factor influencing the onset and outcomes of psychiatric disorders. Whereas, previous research has shown long-term schizophrenia is associated with various nutritional deficiencies, this meta-analysis aimed to determine the prevalence and extent of nutritional deficits in first-episode psychosis (FEP).

Method

A search of electronic databases conducted in July 2017 identified 28 eligible studies, examining blood levels of 6 vitamins and 10 minerals across 2612 individuals: 1221 individuals with FEP and 1391 control subjects. Meta-analyses compared nutrient levels in FEP to nonpsychiatric controls. Clinical correlates of nutritional status in patient samples were systematically reviewed.

Results

Significantly lower blood levels of folate (N = 6, n = 827, g = -0.624, 95% confidence interval [CI] = -1.176 to -0.072, P = .027) and vitamin D (N = 7, n = 906, g = -1.055, 95% CI = -1.99 to -0.119, P = .027) were found in FEP compared to healthy controls. Synthesis of clinical correlates found both folate and vitamin D held significant inverse relationships with psychiatric symptoms in FEP. There was also limited evidence for serum level reductions of vitamin C (N = 2, n = 96, g = -2.207, 95% CI = -3.71 to -0.71, P = .004). No differences were found for other vitamins or minerals.

Conclusions

Deficits in vitamin D and folate previously observed in long-term schizophrenia appear to exist from illness onset, and are associated with worse symptomology. Further research must examine the direction and nature of these relationships (ie, mediator, moderator, or marker) with clinical status in FEP. Future trials assessing efficacy of nutrient supplementation in FEP samples should consider targeting and stratifying for baseline deficiency.

Profiling of Amino Acids and Their Derivatives Biogenic Amines Before and After Antipsychotic Treatment in First-Episode Psychosis

Schizophrenia (SCH) is a heterogeneous disorder, deriving from a potential multitude of etiopathogenetic factors. During the past few years there has been an increasing interest in the role of circulating amino acids (AAs) and biogenic amines (BAs) in the pathophysiology of SCH. In the present study, we aimed to provide an insight into the potential role of alterations in levels of AAs and BAs as well as examine their more specific metabolic shifts in relation to early stage of SCH. We measured 21 AAs and 17 BAs in serum samples of patients with first-episode psychosis (FEP) before and after 7-month antipsychotic treatment in comparison to control subjects (CSs). According to multivariate analysis, antipsychotic-naïve FEP patients had significantly higher levels of taurine and spermine, whereas values of proline (Pro), alpha-aminoadipic acid (alpha-AAA), kynurenine (Kyn), valine (Val), tyrosine (Tyr), citrulline (Citr), tryptophan (Trp), and histidine (His) were diminished compared to CSs. Increased levels of taurine and spermine, as well as reduced levels of alpha-AAA and Kyn probably reflect the compromised function of N-methyl-D-aspartate (NMDA) receptors in patients. The decreased levels of Pro (AA modulating the function of glutamate decarboxylase) likely reflect the imbalanced function of gamma-aminobutyric acid (GABA) system in the brain of FEP patients. The alterations in ratio between Tyr and phenylalanine (Phe) can be taken as a sign of compromised function of dopaminergic system. These metabolic shifts were reinstated by 7-month antipsychotic treatment. Serum metabolic profiles can be regarded as important indicators to investigate clinical course of SCH and treatment response.

Oxidative stress biomarkers and clinical dimensions in first 10 years of schizophrenia

INTRODUCTION

Several studies have described increased oxidative stress parameters in patients with schizophrenia. The objectives of the current study were to identify potential oxidative stress biomarkers in stable patients during first 10 years of schizophrenia and determine if they are associated with specific clinical dimensions.

MATERIAL AND METHODS

Seventy-three clinically stable outpatients with schizophrenia and 73 sex and age-matched healthy controls were recruited. Sociodemographic, clinical and biological data were collected at enrollment. Blood biomarkers included homocysteine, the percentage of hemolysis, lipid peroxidation subproducts, and as an antioxidant biomarker, catalase activity in erythrocytes.

RESULTS

Comparative analyses after controlling for smoking and metabolic syndrome evidenced a significant increase in catalase activity in patients. Also, lower lipid peroxidation levels showed an association with negative symptoms.

CONCLUSIONS

In conclusion, compensatory antioxidant mechanisms might be increased in stable patients with schizophrenia at early stages. Furthermore, there may be an inverse relationship between oxidative stress and negative dimension.

Quantitative Analysis of l-Arginine, Dimethylated Arginine Derivatives, l-Citrulline, and Dimethylamine in Human Serum Using Liquid Chromatography-Mass Spectrometric Method

ABSTRACT

Nitric oxide (NO) is a small molecule involved in the regulation of many physiological processes. It plays a crucial role in the regulation of nervous system, immune and inflammatory responses, and blood flow. NO is synthesized by nitric oxide synthase (NOS) during two-step oxidation of l-arginine to l-citrulline. Intermediates and derivatives of NO metabolism, such as l-arginine, l-citrulline, asymmetrical dimethylarginine (ADMA), symmetrical dimethylarginine (SDMA), and dimethylamine (DMA), are investigated as potential biomarkers. In this article, we present a novel analytical method that allowed for simultaneous analysis of l-arginine, ADMA, SDMA, l-citrulline, and DMA, in a single-step extraction and derivatization using benzoyl chloride. In brief, aliquots of serum were mixed with internal standard solution mixture (50 µM D6-DMA, 20 µM D7-ADMA, and 100 µM D7-arginine) and 0.025 M borate buffer, pH 9.2 (10:1:5). The derivatization process was performed at 25 °C for 5 min using 10% benzoyl chloride. A reverse phase column was used for chromatographic separation. Quantitation was performed using following ions (m/z): 279.1457, 286.1749, 307.1717, 314.2076, 280.1297, 150.0919, and 156.1113 for l-arginine, D7-arginine, ADMA, SDMA, D7-ADMA, l-citrulline, DMA, and D6-DMA, respectively. The method was validated, and its assay linearity, accuracy and precision, recovery, and limits of detection (1.7 µM l-arginine, 0.03 µM ADMA, 0.02 µM SDMA, 0.36 µM l-citrulline, 0.06 µM DMA) and quantification (3.2 µM l-arginine, 0.08 µM ADMA, 0.05 µM SDMA, 1.08 µM l-citrulline, 0.19 µM DMA) were determined. The method is sensitive, reliable, repeatable, and reproducible. It can be applied in the routine clinical/diagnostic laboratory.

GRAPHICAL ABSTRACT

Antioxidant and anti-inflammatory nutrient status, supplementation, and mechanisms in patients with schizophrenia

Over 50 million people around the world suffer from schizophrenia, a severe mental illness characterized by misinterpretation of reality. Although the exact causes of schizophrenia are still unknown, studies have indicated that inflammation and oxidative stress may play an important role in the etiology of the disease. Pro-inflammatory cytokines are crucial for normal central nervous development and proper functioning of neural networks and neurotransmitters. Patients with schizophrenia tend to have abnormal immune activation resulting in elevated pro-inflammatory cytokine levels, ultimately leading to functional brain impairments. Patients with schizophrenia have also been found to suffer from oxidative stress, a result of an imbalance between the production of free radicals and the ability to detoxify their harmful effects. Furthermore, inflammation and oxidative stress are implicated to be related to the severity of psychotic symptoms. Several nutrients are known to have anti-inflammatory and antioxidant functions through various mechanisms in our body. The present review evaluates studies and literature that address the status and supplementation of omega-3 polyunsaturated fatty acids, vitamin D, B vitamins (B6, folate, B12), vitamin E, and carotenoids in different stages of schizophrenia. The possible anti-inflammatory and antioxidant mechanisms of action of each nutrient are discussed.

The effects of vitamin and mineral supplementation on symptoms of schizophrenia: a systematic review and meta-analysis

BACKGROUND

When used as an adjunctive with antipsychotics, certain vitamins and minerals may be effective for improving symptomatic outcomes of schizophrenia, by restoring nutritional deficits, reducing oxidative stress, or modulating neurological pathways.

METHOD

We conducted a systematic review of all randomized controlled trials (RCTs) reporting effects of vitamin and/or mineral supplements on psychiatric symptoms in people with schizophrenia. Random-effects meta-analyses were used to calculate the standardized mean difference between nutrient and placebo treatments.

RESULTS

An electronic database search in July 2016 identified 18 eligible RCTs, with outcome data for 832 patients. Pooled effects showed that vitamin B supplementation (including B6, B8 and B12) reduced psychiatric symptoms significantly more than control conditions [g = 0.508, 95% confidence interval (CI) 0.01-1.01, p = 0.047, I 2 = 72.3%]. Similar effects were observed among vitamin B RCTs which used intention-to-treat analyses (g = 0.734, 95% CI 0.00-1.49, p = 0.051). However, no effects of B vitamins were observed in individual domains of positive and negative symptoms (both p > 0.1). Meta-regression analyses showed that shorter illness duration was associated with greater vitamin B effectiveness (p = 0.001). There were no overall effects from antioxidant vitamins, inositol or dietary minerals on psychiatric symptoms.

CONCLUSIONS

There is preliminary evidence that certain vitamin and mineral supplements may reduce psychiatric symptoms in some people with schizophrenia. Further research is needed to examine how the benefits of supplementation relate to nutrient deficits and the impact upon underlying neurobiological pathways, in order to establish optimal nutrient formulations for improving clinical outcomes in this population. Future studies should also explore the effects of combining beneficial nutrients within multi-nutrient formulas.

Effect of risperidone on serum homocysteine levels in first-episode, drug-naïve patients with schizophrenia

Some studies have shown that homocysteine (Hcy) levels are increased in patients with schizophrenia, and may be involved in its pathophysiology. The purpose of this study was to investigate the effect of the atypical antipsychotic drug risperidone on serum Hcy levels and to explore the relationship between the changes in Hcy levels and the therapeutic outcome, which, to our best knowledge have not been investigated. Fifty-six first-episode and drug-naïve inpatients with schizophrenia were assigned to a 12-week treatment regime with risperidone. Clinical efficacy was determined with the Positive And Negative Syndrome Scale (PANSS). Serum Hcy levels were measured by sandwich enzyme-linked immunosorbent assay in schizophrenia patients before and after the 12-week treatment, and the values were compared with those of fifty-six age- and gender- matched healthy controls. Serum Hcy levels were significantly higher in first-episode and drug-naïve patients than in control subjects (11.18±4.53 vs. 5.99±3.61μmol/L, F=37.195, df=1, p=1.73×10^-8). Moreover, a significant positive correlation between Hcy levels and PANSS negative sub-score was observed (r=0.515; p=4.81×10^-5). Serum Hcy levels were significantly decreased in patients after risperidone treatment (baseline: 11.18±4.53μmol/L vs. post-treatment: 8.98±4.07μmol/L, t=3.857, p=3.034×10^-4). At post-treatment, there was a significant negative relationship between serum Hcy levels and PANSS negative sub-scores (r=-0.288, p=0.032). High Hcy levels at the onset of psychosis suggests that it may contribute to the pathogenesis of schizophrenia and is related to clinical psychopathology. Serum Hcy levels were significantly decreased in schizophrenia patients after risperidone treatment.

Cumulative effect of the plasma total homocysteine-related genetic variants on schizophrenia risk

Previous studies suggest that elevated total homocysteine levels and the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, which correlates with plasma total homocysteine levels, are risk factors for schizophrenia (SCZ). Recently, a large genome-wide association study (GWAS) of plasma total homocysteine levels in individuals of European ancestry identified many single-nucleotide polymorphisms (SNPs) (n=13,974). The primary purpose of this study was to examine the association between these plasma total homocysteine-related SNPs and SCZ in the Japanese population. First, we investigated associations between six SNPs and plasma total homocysteine levels in non-psychiatric subjects in the Japanese population (n=1030). Then, we evaluated the cumulative effects of three SNPs on SCZ risk by calculating the Genotype Risk Score (GRS) (1120 cases, 2643 controls). Of the six SNPs examined, we replicated similar associations with the European GWAS at four loci (CENPQ, CPS1, MTHFR, and MUT). GRS based on three SNPs (CENPQ, CPS1, and MTHFR) was significantly associated with SCZ. Our findings suggest that common polygenic variations, which are associated with the plasma total homocysteine levels, may contribute to the risk of SCZ.

Genetic Variation in One-Carbon Metabolism and Changes in Metabolic Parameters in First-Episode Schizophrenia Patients

BACKGROUND

In this study, we aimed to investigate the effects of polymorphisms in genes encoding 1-carbon metabolism enzymes on differential development of metabolic parameters during 12 weeks of treatment with second-generation antipsychotics in first-episode schizophrenia patients.

METHODS

The following polymorphisms in 1-carbon metabolism genes were genotyped: MTHFR (C677T and A1298C), MTHFD1 (G1958A), MTRR (A66G), and BHMT (G742A). A broad panel of metabolic parameters including body mass index, waist circumference, total cholesterol low and high density lipoproteins, triglycerides, homocysteine, folate, and vitamin B12 was determined.

RESULTS

There was a significant effect of the interaction between the MTHFR C677T polymorphism and time on body mass index and waist circumference in the allelic and genotype analyses. Indeed, patients with the MTHFR 677CC genotype had higher increase in body mass index and waist circumference compared with other corresponding genotypes or the MTHFR 677T allele carriers (CT and TT genotypes). In addition, patients with the MTHFR 677TT genotype had higher waist circumference in all time points. Similarly, patients with the MTHFR 677TT genotype had higher body mass index in all time points, but this effect was not significant after correction for multiple testing.

CONCLUSIONS

Our results indicate that the MTHFR C677T polymorphism may predict antipsychotic-induced weight gain. Effects of the MTHFR C677T polymorphism might be different in initial exposure to antipsychotics compared with long-term perspective.

Lower folate levels in schizophrenia: A meta-analysis

This meta-analysis aimed to estimate the association between folate level and schizophrenia in order to provide the evidence for the treatment of schizophrenia. Data were extracted from all the studies meeting our inclusion and exclusion criteria. The association between the folate level and schizophrenia was evaluated by the standardized mean difference (SMD) and 95% confidence interval (CI). The 20 published articles of our meta-analysis included 1463 (53.4%) cases and 1276 (46.6%) controls. The folate level was significantly lower in schizophrenia cases than in healthy controls. Subgroup analysis showed the folate level was lower in cases from Asia subgroup than in healthy controls. Sensitivity analysis showed that the current results were credible and reliable and the funnel plots indicated no publication bias in our meta-analysis. Our study indicates that schizophrenia patients may have lower folate levels. More epidemiological and laboratory studies are still needed to confirm whether it is necessary to supplement folate in schizophrenia patients.

Metabolic dysregulation in first-episode schizophrenia patients with respect to genetic variation in one-carbon metabolism

The aim of this study was to investigate the prevalence of metabolic disturbances in patients with first-episode schizophrenia (FES) and test the hypothesis that genetic variation in one-carbon metabolism may account for metabolic dysregulation in early psychosis. We measured fasting glucose, lipid profile parameters, homocysteine, folate and vitamin B12 in 135 patients with FES and 146 healthy controls (HCs). Polymorphisms in the following genes were determined: MTHFR (C677T and A1298C), MTHFD1 (G1958A), MTRR (A66G) and BHMT (G742A). Serum levels of folate and high-density lipoproteins (HDL) were significantly lower in patients with FES compared to HCs. In turn, serum levels of homocysteine and triglycerides were significantly higher in patients with FES than in HCs. Prevalence of hyperhomocysteinemia, low folate and HDL levels together with dyslipidemia was significantly higher in patients with FES compared to HCs. Higher homocysteine levels, lower vitamin B12 levels and the presence of metabolic syndrome were associated with higher severity of negative symptoms. None of studied polymorphisms was associated with schizophrenia risk. Several associations between studied polymorphisms and cardio-metabolic parameters were found. None of them remained significant after Bonferroni correction. Our results indicate that metabolic dysregulation in patients with FES is not associated with genetic variation in one-carbon metabolism.

Serum folate levels in schizophrenia: A meta-analysis

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.

CT genotype of 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is protector factor of major depressive disorder in the Tunisian population: a case control study

BACKGROUND

Major depressive disorder (MDD) is a common psychiatric disorder with considerable mortality. Death from unnatural causes, largely suicidal or quasi-suicidal, has a particularly high risk for the functional disorders, especially depression and schizophrenia. One of the prospective risk factors for this disease is hyperhomocysteinemia and folate deficiency. The methylenetetrahydrofolate reductase (MTHFR) gene encodes for a 5-methylenetetrahydrofolate reductase involved in folate metabolism and neurotransmitter synthesis. The aim of this research is to study the association between the C677T polymorphism of MTHFR gene and depression in Tunisian population, to explore their relationship with clinical and therapeutic characteristics of this disease. And it may lead to discover a novel marker to identify a patient with a higher risk of development of depressive disorder to be. This marker can be used for better therapeutic management and prevent disease installation.

METHODS

Our study included 208 depressive patients, 187 controls aged between 44.1 ± 13.5 and 38.9 ± 13.2 years, respectively. MTHFR gene polymorphisms were determined by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism).

RESULTS

No significant difference was detected in the distribution of the genotype frequencies of MTHFR C677T polymorphisms (χ (2) = 5.443, df = 2, p = 0.066) between patients and controls. But when we study the risk of these genotypes, CT genotype is significantly more frequent in controls compared to patients, it may be a protection from depression (OR = 0.655, CI 95 % = 0.432-0.995, p = 0.047, OR* = 0.638, CI 95 %* = 0.415-0.983, p* = 0.04, before and after adjustment). Women, TT Genotype can increase four times the risk to be depressive. Addictive behavior seems to be associated with CT genotype and there was no significant association between clinical and therapeutic characteristics and this polymorphism.

CONCLUSION

This paper is the first study to prove that CT genotype of MTHFR C677T polymorphism may protect from depression and TT genotype seems to be associated with women's depression. Further studies are required with other polymorphisms and biochemical factors that must be investigated to clarify the implication of MTHFR C677T polymorphism in the pathophysiology of depression.

Multi-regression analysis revealed a relationship between l-serine and methionine, a component of one-carbon metabolism, in the normal control but not in the schizophrenia

BACKGROUND

Alterations in one-carbon metabolism (OCM) have been observed in patients with schizophrenia (SZ), but a comprehensive study of OCM has not yet been conducted. A carbon atom is transferred from l-serine to methionine during OCM, but the relationship between l-serine and methionine in SZ is not yet known. We investigated the relationship between l-serine and methionine to obtain a comprehensive understanding of OCM in SZ.

METHODS

We recruited forty-five patients with SZ and thirty normal controls (NC). Whole blood, plasma, and DNA specimens were obtained from all participants. Plasma l-serine, d-serine, glycine, methionine, and total homocysteine levels were measured using high-performance liquid chromatography. Plasma vitamin B12 and total folate were measured using a chemiluminescent protein-binding immunoassay. Clinical symptoms were estimated using the positive and negative syndrome scale (PANSS). The methylenetetrahydrofolate reductase (MTHFR) C667T genotype and A298C genotype, which are involved in MTHFR activity, were determined using the TaqMan genotyping assay system.

RESULTS

Analysis of variance was used to confirm that the SZ cohort has higher plasma homocysteine levels and lower plasma folate levels than the NC group. Multi-regression analysis revealed a relationship between l-serine and methionine in the NC group but not in the SZ group. The MTHFR genotype did not affect the relationship between l-serine and methionine in each group. The total PANSS score was significantly related to d-serine and folate levels and to age. Positive PANSS scores were significantly related to both glycine and sex. In addition, both glycine and d-serine were significantly correlated with negative PANSS scores.

CONCLUSIONS

We found impairment of the relationship between l-serine and methionine in SZ. Clinical symptoms of SZ were partially correlated with the OCM components. These findings contributed to our understanding of OCM alteration in SZ and may explain why the alteration occurs.

Severe Hyperhomocysteinemia Decreases Respiratory Enzyme and Na(+)-K(+) ATPase Activities, and Leads to Mitochondrial Alterations in Rat Amygdala

Severe hyperhomocysteinemia is caused by increased plasma levels of homocysteine (Hcy), a methionine derivative, and is associated with cerebral disorders. Creatine supplementation has emerged as an adjuvant to protect against neurodegenerative diseases, due to its potential antioxidant role. Here, we examined the effects of severe hyperhomocysteinemia on brain metabolism, and evaluated a possible neuroprotective role of creatine in hyperhomocysteinemia, by concomitant treatment with Hcy and creatine (50 mg/Kg body weight). Hyperhomocysteinemia was induced in young rats (6-day-old) by treatment with homocysteine (0.3-0.6 µmol/g body weight) for 23 days, and then the following parameters of rat amygdala were evaluated: (1) the activity of the respiratory chain complexes succinate dehydrogenase, complex II and cytochrome c oxidase; (2) mitochondrial mass and membrane potential; (3) the levels of necrosis and apoptosis; and (4) the activity and immunocontent of Na(+),K(+)-ATPase. Hcy treatment decreased the activities of succinate dehydrogenase and cytochrome c oxidase, but did not alter complex II activity. Hcy treatment also increased the number of cells with high mitochondrial mass, high mitochondrial membrane potential, and in late apoptosis. Importantly, creatine administration prevented some of the key effects of Hcy administration on the amygdala. We also observed a decrease in the activity and immunocontent of the α1 subunit of the Na(+),K(+)-ATPase in amygdala after Hcy- treatment. Our findings support the notion that Hcy modulates mitochondrial function and bioenergetics in the brain, as well as Na(+),K(+)-ATPase activity, and suggest that creatine might represent an effective adjuvant to protect against the effects of high Hcy plasma levels.

The history of childhood trauma is associated with lipid disturbances and blood pressure in adult first-episode schizophrenia patients

OBJECTIVE

It has repeatedly been found that early-life traumatic events may contribute to metabolic dysregulation. Therefore, the aim of this study was to investigate the association between the history of childhood trauma and cardiovascular risk factors in first-episode schizophrenia (FES) patients.

METHOD

The history of childhood trauma was assessed using the Early Trauma Inventory Self Report - Short Form (ETISR-SF) in 83 FES patients. Based on the ETISR-SF, patients were divided into those with positive and negative history of childhood trauma: FES(+) and FES(-) patients. Serum levels of fasting glucose lipids, homocysteine, vitamin B12 and folate, as well as anthropometric parameters and resting systolic and diastolic blood pressure (SBP and DBP) were measured.

RESULTS

The history of childhood trauma was associated with higher low-density lipoprotein (LDL) levels, SBP and DBP after covarying for age, gender, body mass index, education and chlorpromazine equivalent. There were significant correlations between scores of distinct ETISR-SF subscales and LDL, high-density lipoprotein, SBP, DBP and the number of metabolic syndrome criteria.

CONCLUSIONS

Results of this study indicate that traumatic events during childhood might be related to higher resting blood pressure and higher LDL levels in adult FES patients.

Effects of second-generation antipsychotics on selected markers of one-carbon metabolism and metabolic syndrome components in first-episode schizophrenia patients

Purpose

Alterations in one-carbon metabolism (OCM) have been repeatedly reported in schizophrenia. However, there is a scarcity of studies addressing the effects of antipsychotics on selected OCM markers in schizophrenia and provided results are inconsistent.

Methods

We recruited 39 first-episode schizophrenia (FES) patients and determined serum profile of total homocysteine (tHcy), folate, vitamin B12, lipoproteins and glucose at baseline and after 12 weeks of treatment with second-generation antipsychotics (SGA) including olanzapine and risperidone in monotherapy.

Results

After 12 weeks of treatment, all patients had significantly higher body mass index (BMI), serum levels of total cholesterol (TC), low-density lipoproteins (LDL), triglycerides (TG) and tHcy together with significantly lower levels of folate and vitamin B12. The analysis of differences between SGA revealed the same biochemical alterations in patients treated with olanzapine as in the whole group, while those receiving risperidone had no statistically significant changes in serum folate, vitamin B12 and TG. There was a significantly higher increase in BMI and TC in patients treated with olanzapine in comparison with those treated with risperidone. Patients receiving olanzapine had a higher decrease in vitamin B12 than those assigned to the treatment with risperidone. Changes in folate, vitamin B12, tHcy and TC levels were significant only in males, even after Bonferroni correction. Multiple regression analysis revealed that changes in tHcy levels are associated with gender and baseline metabolic parameters (BMI, glucose, TC, LDL and HDL) but not with selected SGA.

Conclusions

These results indicate that SGA may influence OCM, especially in first-episode schizophrenia (FES) males.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-014-1762-2) contains supplementary material, which is available to authorized users.

Homocysteine levels in schizophrenia and affective disorders-focus on cognition

Although homocysteine (Hcy) has been widely implicated in the etiology of various physical health impairments, especially cardiovascular diseases, overwhelming evidence indicates that Hcy is also involved in the pathophysiology of schizophrenia and affective disorders. There are several mechanisms linking Hcy to biological underpinnings of psychiatric disorders. It has been found that Hcy interacts with NMDA receptors, initiates oxidative stress, induces apoptosis, triggers mitochondrial dysfunction and leads to vascular damage. Elevated Hcy levels might also contribute to cognitive impairment that is widely observed among patients with affective disorders and schizophrenia. Supplementation of vitamins B and folic acid has been proved to be effective in lowering Hcy levels. There are also studies showing that this supplementation strategy might be beneficial for schizophrenia patients with respect to alleviating negative symptoms. However, there are no studies addressing the influence of add-on therapies with folate and vitamins B on cognitive performance of patients with schizophrenia and affective disorders. In this article, we provide an overview of Hcy metabolism in psychiatric disorders focusing on cognitive correlates and indicating future directions and perspectives.