Homocysteine as a potential biomarker in bipolar disorders: a critical review and suggestions for improved studies

Homocysteine, hopelessness, rumination, affective temperaments, and clinical course in patients with bipolar disorder-1

PURPOSE

This study aimed to explore the associations between homocysteine, rumination, affective temperaments, clinical features, and hopelessness in bipolar disorder-1 (BD-1).

MATERIALS AND METHODS

In total, 57 euthymic patients with BD-1 and 57 healthy controls were included. The Beck Hopelessness Scale (BHS), Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A), and Ruminative Responses Scale Short Form (RRS-SF) were administered. Homocysteine, folate, and vitamin B12 levels were measured.

RESULTS

The BHS total (p = 0.047), TEMPS-A irritable (p = 0.007), and TEMPS-A cyclothymic (p= 0.001) scores were significantly higher than the control group in the BD-1 group. Hyperhomocysteinemia (HHcy) was found in 33.3% of the patients (n = 19). In the HHcy group, age of onset of disease (p = 0.020) was significantly lower than the non-HHcy group in patients. Previous suicide attempt number was significantly correlated with scores of reflective pondering, brooding, and global rumination in BD-1 (p ˂ 0.05). Except for hyperthymic temperament, all types of affective temperaments were correlated with the scores of RRS-SF brooding (p ˂ 0.05) in the BD-1 group. The RRS-SF brooding scores significantly correlated with the BHS total scores (r = 0.263, p < 0.05); the TEMPS-A hyperthymic (β = -0.351, p = 0.001) and TEMPS-A irritable (β = 0.536, p < 0.001) scores significantly predicted the BHS total scores in the BD-1 group.

CONCLUSIONS

The findings may lead clinical efforts and future clinical trials to explore and intervene in related sources and presentations of BD-1's adverse consequences.

Homocysteine-Potential Novel Diagnostic Indicator of Health and Disease in Horses

Homocysteine is an endogenous, non-protein sulfuric amino acid, an intermediate metabolite formed by the methionine transmethylation reaction. Its elevated serum concentration in humans, hyperhomocysteinemia, is a sensitive indicator and a risk factor for coagulation disorders, cardiovascular diseases and dementia. However, the role of homocysteine in veterinary species has not been unequivocally established. Although some research has been conducted in dogs, cats, cattle and pigs, relatively few studies on homocysteine have been conducted in horses. So far, it has been established in this species that homocysteine has an atherogenic effect, plays a role in early embryo mortality and is responsible for the induction of oxidative stress. These preliminary findings support establishing a reference range in a normal population of horses, including horses in training and merit further investigations into the role of this amino acid in health and disease in this species.

Vitamin B12, homocysteine, and folic acid in patients suffering from bipolar disorders: Relationship with suicide

OBJECTIVES

Vitamin B12, folic acid, and homocysteine play a key role in 'one-carbon metabolism', involved in different brain processes. Altered levels have been reported in mood disorders (MDs), particularly in major depression (MDD), while the information in bipolar disorders (BDs) is limited. The present study aimed at assessing vitamin B12, homocysteine, and folic acid in 69 bipolar inpatients.

METHODS

Twenty-seven patients were diagnosed with BDI, 15 BDII, 16 schizoaffective disorders, and 11 MDD, according to DSM-5 criteria. The clinical picture was assessed by the MINI, HRSD, YMRS, and CGI. The blood parameters were measured according to common clinical-chemical methods.

RESULTS

Thirty-four patients had significantly lower vitamin B12, and 14 higher homocysteine levels than normative values. Folic acid levels were normal in the majority of the sample. Patients with a family history of suicide showed significantly lower levels of vitamin B12.

CONCLUSIONS

Our results underline the utility of assessing vitamin B12, homocysteine, and folic acid in patients with BD. Although other studies are necessary, the present findings that lower levels of vitamin B12 seem typical of patients with a family history of suicide independently from the phase of illness suggest that they might constitute a possible predictor of suicide.

The Correlations Between Serum Hcy Level and Seizures and Cognitive Function in Patients After Stroke

BACKGROUNDS

Post-stroke cognitive dysfunction (PSCI), a set of illnesses ranging from moderate cognitive impairment to dementia, which is one of the most prevalent consequences following a stroke. Homocysteine (Hcy) has been related to a number of neurological and systemic diseases. It's also a known risk factor for cardiovascular disease and systemic atherosclerosis (CVD). The link between Hcy and PSCI, on the other hand, is unknown.

METHODS

Our hospital evaluated 325 patients with acute cerebral infarction between January 1, 2018 and December 1, 2021. There are biological markers and baseline data available. Patients were divided into two groups based on the results of the Montreal Cognitive Assessment (MoCA). The researchers performed logistic regression analysis to find variables that may be linked to PSCI.

RESULTS

HCY levels were significantly higher in PSCI patients than in non-PSCI patients. Age, education, seizure manifestation, and income level were all shown to be independent risk variables for PSCI in a multivariate logistic analysis. Hcy levels in PSCI patients differed considerably between the high and low groups. The high and low Hcy levels groups had significantly varied hypertension histories and urine levels. Hcy levels in PSCI patients differed considerably between the high and low groups. The high and low Hcy levels groups had significantly varied hypertension histories and urine levels.

CONCLUSION

Serum Hcy levels have been linked to PSCI in post-stroke patients, and researchers believe that serum Hcy levels will diminish PSCI.

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.

Melatonin as a Reducer of Neuro- and Vasculotoxic Oxidative Stress Induced by Homocysteine

The antioxidant properties of melatonin can be successfully used to reduce the effects of oxidative stress caused by homocysteine. The beneficial actions of melatonin are mainly due to its ability to inhibit the generation of the hydroxyl radical during the oxidation of homocysteine. Melatonin protects endothelial cells, neurons, and glia against the action of oxygen radicals generated by homocysteine and prevents the structural changes in cells that lead to impaired contractility of blood vessels and neuronal degeneration. It can be, therefore, assumed that the results obtained in experiments performed mainly in the in vitro models and occasionally in animal models may clear the way to clinical applications of melatonin in patients with hyperhomocysteinemia, who exhibit a higher risk of developing neurodegenerative diseases (e.g., Parkinson’s disease or Alzheimer’s disease) and cardiovascular diseases of atherothrombotic etiology. However, the results that have been obtained so far are scarce and have seldom been performed on advanced in vivo models. All findings predominately originate from the use of in vitro models and the scarcity of clinical evidence is huge. Thus, this mini-review should be considered as a summary of the outcomes of the initial research in the field concerning the use of melatonin as a possibly efficient attenuator of oxidative stress induced by homocysteine.

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.

High-sensitive C-reactive protein and homocysteine levels in patients with newly diagnosed bipolar disorder, their first-degree relatives, and healthy control persons-Results from a clinical study

Background

Changes in inflammatory and metabolic markers are implicated in the pathogenesis in both the development and progression of bipolar disorder (BD). Notwithstanding, these markers have not been investigated in newly diagnosed BD.

Methods

We compared high-sensitive C-reactive protein (hs-CRP) and homocysteine (Hcy) levels in 372 patients with newly diagnosed BD, 106 unaffected first-degree relatives (URs), and 201 healthy control persons (HCs). Within the patient group, we also investigated possible associations between hs-CRP and Hcy, respectively, with illness-related characteristics and psychotropic medication.

Results

No statistically significant differences in Hcy and hs-CRP levels were found when comparing BD and URs with HCs. Similarly, there were no differences when comparing only patients in remission or patients with affective symptoms, respectively, with HCs. Hcy levels were found to be 11.9% (95% CI: 1.030–1.219) higher in patients with BD when compared with their URs (p = 0.008), when adjusting for folate and cobalamin status, age, sex, and self-reported activity levels. Hcy levels were significantly associated with folate, cobalamin, gender, and age in all models (p < 0.05).

Conclusion

Our results do not support hs-CRP or Hcy as markers in newly diagnosed BD.

Homocysteine, chronotype and clinical course in bipolar disorder patients

Purpose: Higher homocysteine (HHcy) levels have been detected in bipolar disorder (BD) patients, and BD patients show circadian rhythm disorders even during remission. Here, we determined the homocysteine (Hcy) levels and chronotype of patients with BD during remission and investigated whether this was related to the clinical course of the disease. Materials and methods: In total, 80 BD outpatients were included. Clinical evaluation was conducted using the Hamilton Depression Rating Scale (HDRS), Young Mania Rating Scale (YMRS), Pittsburgh Sleep Quality Index (PSQI) and the Morningness-Eveningness Questionnaire (MEQ). Hcy, folic acid, vitamin B12 levels and protein consumption the day before clinical evaluation were measured.Results and conclusions: HHcy was found in 11 patients (8.8%), most of whom were males (n = 8, 72.7%). During the course of BD, patients with HHcy had significantly more mixed episodes than patients without HHcy (p = .007, z = -2696). In addition, patients with HHcy had significantly lower MEQ scores than patients without HHcy (p = .04, t = 2018). There was no significant difference in chronotype between patients with and without HHcy. The HHcy group had significantly lower levels of vitamin B12 (p = .003, t = 2870). There were no statistically significant differences in daily protein intake and folic acid levels between HHcy and non-HHcy groups. Our study showed a significant relationship between the number of mixed episodes and HHcy. In terms of potential confounds, patients who abused alcohol were excluded, but alcohol consumption was not evaluated. This result should be considered in BD and should be evaluated in larger samples of BD 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.

Sex differences in the prevalence and clinical correlates of hyperhomocysteinemia in patients with bipolar disorder

OBJECTIVE

Sex differences in bipolar disorder are well recognized but little attention has been paid to sex differences in homocysteine or hyperhomocysteinemia in bipolar patients. This study compared gender differences in homocysteine levels and rates of hyperhomocysteinemia in Chinese inpatients with bipolar disorder.

METHODS

A total of 198 BD patients and 84 healthy controls were enrolled. The Young Mania Rating Scale, Hamilton Depression Rating Scale, and the Clinical Global Impressions-Severity scale were used to assess the affective symptomatology. Fasting plasma Hcy levels were measured by high-performance liquid chromatography.

RESULTS

Men had higher homocysteine levels than women and the prevalence of hyperhomocysteinemia in male patients was approximately twice that in female patients. Logistic regression analyses showed that HHcy was associated with less frequent use of valproate in males and being overweight in females. Further correlation analysis and multivariate regression analysis demonstrated that Hcy levels were inversely correlated with valproate treatment in men and positively associated with overweight in women.

CONCLUSIONS

In bipolar patients, there are significant differences between sexes in the levels of homocysteine and prevalence of hyperhomocysteinemia. This appears to be associated with lower prevalence of valproate prescribing in men and with being overweight in women.

Efficacy of folic acid as an adjunct to lithium therapy on manic-like behaviors, oxidative stress and inflammatory parameters in an animal model of mania

Evaluate the efficacy of folic acid (FA) as a therapeutic adjunct to lithium (Li) on the manic-like behaviors as well as parameters of oxidative stress and inflammation in an animal model of mania induced by m-amphetamine (m-AMPH). Wistar rats first received m-AMPH or saline (NaCl 0.9%, Sal) for 14 days. Between the 8th and 14th day, rats were treated with water, Li, FA or a combination of thereof drugs (Li + FA). Manic-like behaviors were assessed in the open-field test. Oxidative stress and inflammation parameters were assessed in the frontal cortex, striatum, and hippocampus. Administration of m-AMPH in rats significantly enhanced the exploratory and locomotor behaviors, as well as the risk-taking and stereotypic behaviors. Li + FA reversed these behavioral alterations elicited by m-AMPH. Administration of this psychostimulant also increased oxidative damage to lipids and proteins, whereas Li + FA reversed these oxidative damages. m-AMPH also induced an increase in the glutathione peroxidase (GPx) activity and a decrease in the glutathione reductase (GR) activity. Li + FA reversed the alteration in GR activity, but not in GPx activity. In addition, m-AMPH increased the IL-1β and TNF-α levels in the rat brain; Li + FA combined therapy reversed the alterations on these inflammatory parameters. FA administration per se reduced the increased TNF-α content induced by m-AMPH. Present study provides evidence that FA is effective as an adjunct to Li standard therapy on manic-like behaviors, oxidative stress and inflammatory parameters in a model of mania induced by m-AMPH.

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.

Gender differences in C-reactive protein and homocysteine modulation of cognitive performance and real-world functioning in bipolar disorder

BACKGROUND

Cognitive and psychosocial impairment has been associated with increased levels of C-reactive protein (CRP) and homocysteine in bipolar disorder, but gender differences have seldom been studied.

METHODS

Two hundred and twenty-four bipolar outpatients were included. Cognitive performance was assessed through the Screen for Cognitive Impairment in Psychiatry (SCIP). Psychosocial functioning was evaluated using the Functioning Assessment Short Test (FAST) and the General Assessment of Functioning (GAF). Homocysteine and CRP levels were determined. Separate analyses were performed by gender. Partial correlations were calculated to test for associations between biomarkers and cognitive and psychosocial functioning. Hierarchical multiple regression was used to assess factors predicting cognitive and psychosocial functioning. Covariates were: age, education, duration of illness, hospital admissions, depressive symptoms, tobacco consumption, and BMI.

RESULTS

A better performance was noted in women in delayed verbal learning (p = 0.010), along with better occupational functioning (p = 0.027) and greater leisure time impairment (p = 0.034). In men, CRP and homocysteine levels were associated with psychosocial dysfunction (interpersonal relationships and financial functioning, respectively). In women, CRP levels correlated with cognitive performance (SCIP total raw score, immediate and delayed verbal learning, and verbal fluency). CRP was a predictor of cognitive performance in women only.

LIMITATIONS

The choice of the cognitive scale and covariates and the lack of a control group may be the main limitations.

CONCLUSIONS

A gender difference was found in biomarker modulation of cognition and psychosocial functioning. A gender-based approach to cognition and real-world functioning should be considered in bipolar disorder to ensure an optimal outcome.

Prevalence and clinical-demographic correlates of hyperhomocysteinemia in inpatients with bipolar disorder in a Han Chinese population

Recent studies have reported that hyperhomocystinemia (HHcy) is highly prevalent in patients with bipolar disorder (BD), placing them at greater risk of cardiovascular disease and possibly serving as a disease biomarker. However, the correlation of HHcy with demographic or clinical parameters is not well known. In this study, we examined the prevalence of HHcy and its association with these parameters in a sample of Chinese BD patients. Fasting plasma homocysteine (Hcy) levels were determined in 198 BD inpatients and 84 healthy controls. HHcy was defined when Hcy concentration exceeded 15.0µmol/L. Affective symptomatology was assessed by the Young Mania Rating Scale, Hamilton Depression Rating Scale and the Clinical Global Impressions severity scale. Compared to healthy controls, BD patients had a significantly higher prevalence (34.85% vs. 19.05%) of HHcy and a higher absolute level of homocysteine. Logistic regression analysis demonstrated that BD patients with HHcy were more likely to be male, have elevated BMI, more frequent treatment on lithium but less on valproate. These results suggest that Chinese inpatients with bipolar disorder have a higher rate of HHcy than the general population, and those at greatest risk are male, have an elevated BMI, and take more lithium but less valproate therapy.