Peripheral Oxidative Stress Markers in Patients with Bipolar Disorder during Euthymia and in Siblings

Evaluating Oxidative Stress Markers in At-Risk Individuals for Bipolar Disorder: A Systematic Review and Meta-Analysis

INTRODUCTION

Bipolar disorder (BD), a mood disorder with recurrent affective episodes and a strong genetic basis is frequently associated with significant comorbidities, both physical and psychiatric, yet its neurobiology remains unclear. Recent evidence underscores oxidative stress as a pivotal factor linking BD to its comorbidities, prompting an investigation into whether this is a sign of a genetic vulnerability or a consequence of the disease. In this study, we systematically reviewed oxidative stress studies conducted on individuals at risk for BD. We performed a meta-analysis on studies examining oxidative DNA damage in these individuals.

METHODS

The literature was searched across the databases PubMed, Web of Science, Scopus, Ovid MEDLINE, and Cochrane to locate studies of oxidative stress markers in relatives of patients with BD compared with healthy controls (from 1946 to March 2024). Studies were considered for inclusion based on the following criteria: (i) involvement of first- or second-degree relatives of individuals diagnosed with BD, (ii) presence of a healthy control group, (iii) reporting of oxidative stress parameters for relatives, including mean and standard deviation or median and interquartile range (25-75%) values, and (iv) publication in the English language. Studies comparing the levels of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) or its tautomer 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in individuals at risk for BD with healthy controls were evaluated using a meta-analysis with the random-effects method. The risk of bias was evaluated using the Risk of Bias in Non-Randomized Studies of Exposure (ROBINS-E) tool.

RESULTS

Eleven studies were included in the systematic review and four studies for the meta-analysis. The meta-analysis included 543 individuals (first-degree relatives of individuals with BD = 238, control = 305). 8-OH-dG levels were found to be increased in first-degree relatives of individuals with BD compared to healthy controls (random effects: Hedges's g = 0.53, 95% CI = 0.36-0.71, p < 0.001). Findings of oxidative stress markers other than oxidative DNA damage in relatives of individuals with BD are limited and scarce.

CONCLUSION

In this meta-analysis, which consists of a limited number of studies, oxidative DNA damage seems to be a trait marker for BD. This finding could be associated with increased comorbidity and a higher risk of premature aging in individuals at risk for BD. However, further studies with larger sample sizes and longitudinal designs are warranted to confirm findings. Clarifying the changes in these markers from individuals at risk for the disorder throughout the course of the illness would help bridge the gap in understanding the role of oxidative pathways in the risk of BD.

A composite immune and vascular stress marker in patients newly diagnosed with bipolar disorder and their unaffected first-degree relatives

AIMS

Substantial evidence emphasizes immune dysregulation in patients with bipolar disorder (BD). However, whether immune dysregulation is present already in the early illness stages of BD or even precedes development of BD is largely unknown. In this study we compared immune and vascular stress markers in patients newly diagnosed with BD, their unaffected first-degree relatives (UR) and healthy control individuals (HC) and investigated the ability a composite immune and vascular stress marker to discriminate between the three groups of participants.

METHODS

In a unique sample including 373 patients newly diagnosed with BD, 95 UR and 190 HC, we compared 47 immune and vascular stress markers at the baseline visit in the ongoing longitudinal Bipolar Illness Onset study. For comparison of individual immune and vascular stress markers between groups, we applied linear mixed models, whereas the composite immune and vascular stress marker was investigated using the SuperLearner ensemble-method.

RESULTS

Compared with HC, patients newly diagnosed with BD had higher levels of the anti-inflammatory interleukin-1 receptor antagonist (IL-1RA) and IL-10, and of the pro-inflammatory IL-6, eotaxin, monocyte chemoattractant protein-1 (MCP-1), MCP-4, Macrophage Derived Chemokine (MDC), and Thymus and Activation-Regulated Chemokine (TARC) in analyses adjusted for sex and age ranging from 26 % higher levels of IL-6 (1.26, 95 %CI: [1.12-1.43], p < 0.001, adjusted p = 0.009) and IL-10 (1.26, 95 %CI: [1.09-1.46], p = 0.002, adjusted p = 0.049), respectively, to 9 % higher eotaxin levels (1.09, 95 %CI: [1.04-1.15], p = 0.001, adjusted p = 0.024). Of these, MDC levels were 12 % higher in BD compared with UR (1.12, 95 %CI: [1.02-1.22], p = 0.001, adjusted p = 0.024). For all other markers, UR showed no difference from patients with BD or HC. Based on a data-driven model, a composite marker including all 47 immune and vascular stress markers, sex, age, BMI, smoking status, and alcohol intake, discriminated patients with BD from HC with a with an area under the receiver operating curve (AUC) of 0.76 (95 % CI: 0.75-0.77) CONCLUSIONS: Higher levels of pro-inflammatory and anti-inflammatory immune markers are present in patients newly diagnosed with BD but not in UR compared with HC, supporting immune dysregulation playing a role in the pathophysiology of BD.

Non-enzymatic antioxidants, macro-minerals and monocyte/high-density lipoprotein cholesterol ratio among patients with bipolar disorder

OBJECTIVE

Recent studies show that oxidative stress is related to the pathogenesis of BD. Non-enzymatic antioxidants, macro-minerals and MHR (monocyte divided by high-density lipoprotein cholesterol) participated oxidative stress and can be obtained quickly in hematological examination. This study used large-scale clinical data to investigate them between BD and healthy controls (HCs), as well as between psychotic and non-psychotic BD to explore their roles in disease progression.

METHODS

A total of 3442 BD-manic (BD-M) and 1405 BD-depression (BD-D) in acute stage and 5000 HCs were enrolled, including 1592 BD-M with psychotic symptoms (P-BD-M), 1850 BD-M without psychotic symptoms (NP-BD-M), 655 P-BD-D, 750 NP-BD-D. The differences in these biological parameter levels among different groups were compared, and the contributing factors for the occurrence of BD-M or BD-D and psychotic symptoms of BD were analyzed.

RESULTS

We found higher levels of Na and MHR, and lower levels of K, Ca and ALB in BD-M or BD-D compared with the HCs respectively; levels of K, Na, Ca, ALB and MHR have differences among P-BD-M, NP-BD-M and HC; levels of K, Na, Ca and ALB have differences among P-BD-D, NP-BD-D and HC. In multiple logistic regression, higher levels of MHR and Na were associated with BD-M; MHR was shown to be independently associated with P-BD-M; K, Na, ALB were shown to be independently associated with P-BD-D.

CONCLUSIONS

Our study highlights the role of oxidative stress in the pathophysiology of BD. There is heterogeneity between BD-M and BD-D, and different oxidative stress mechanisms of psychotic symptoms exist in BD-M and BD-D.

Oxidative stress parameters and antioxidants in adults with unipolar or bipolar depression versus healthy controls: Systematic review and meta-analysis

BACKGROUND

To study differences in oxidative stress markers and antioxidants among patients with bipolar depression (BPD) and unipolar depression (UPD).

METHODS

Data sources. Electronic MEDLINE/PubMed/Cochrane Library/Scopus/TripDatabase database search until 30/06/2021.

STUDY SELECTION

Included were articles comparing antioxidant or oxidative stress markers between adults with BPD or UPD and healthy controls (HCs).

DATA EXTRACTION

Two authors extracted data independently. Random effects meta-analysis, calculating standardized mean differences for results from ≥3 studies.

RESULTS

Oxidative stress markers reported in 40 studies -1 published repeatedly- (UPD, studies = 30 n = 3072; their HCs, n = 2856; BPD, studies = 11 n = 393; their HCs, n = 540; with 1 study reporting on both UPD and BPD) included thiobarbituric acid reactive substances (TBARS), antioxidant uric acid and antioxidant-enhancing enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GPX). Compared with HCs, UPD and BPD were associated with significantly higher levels of TBARS, without differences between UPD and BPD (P = 0.11). Compared with HCs, UPD and BPD did not differ regarding the activity of the CAT (P = 0.28), SOD (P = 0.87) and GPX (P = 0.25) enzymes. However, uric acid levels were significantly higher vs HCs in BPD than in UPD among adult patients (P = 0.004). Results were heterogenous, which, for some parameters, decreased after stratification by the blood source (serum, plasma red blood cells, whole blood).

LIMITATIONS

The main limitations are the small number of studies/participants in the BPD subgroup, and heterogeneity of the results.

SUMMATIONS

Both BPD and UPD may be associated with an impaired oxidative stress balance, with significantly higher uric acid levels vs. HCs in UPD than in BPD.

A cross-sectional healthy-control study of serum inflammatory biomarkers interleukin (IL)-1B and IL-2R in panic disorder patients and their offspring

Alterations in the immune system have been associated with a variety of mental illnesses. An increase in circulating inflammatory cytokines is observed not only in people with mental disorders but also in their first-degree relatives. A considerable amount of data support the link between immune system activation and panic disorder (PD) pathogenesis, while it is still unclear whether differential immunological reactivity represents a propensity, a measure of disease activity, or both. To better understand the role of cytokines in PD pathophysiology, we compared the levels of serum inflammatory biomarkers interleukin (IL)-1B and IL-2R among PD patients, offspring of PD patients and healthy controls. The offspring of PD patients were evaluated by a psychiatrist and were considered unaffected by any mental disorder at the time of the evaluation. Concentrations of the cytokines IL-1B and IL-2R were assessed using the Immulite System (Diagnostic Products Corporation). The levels of proinflammatory markers IL-1B and IL-2R were increased in PD patients compared to those of controls, but offspring of PD patients and healthy controls demonstrated no differences regarding peripheral interleukin levels. Our findings suggest that interleukins might represent a disease-dependent marker in PD.

Malondialdehyde as a candidate biomarker for bipolar disorder: A meta-analysis

Malondialdehyde (MDA) represents one of the final products of lipid peroxidation that is thought to be enhanced and accelerated in patients affected by bipolar disorder (BD). Purpose of the present article is to critically summarize the available data about MDA as a candidate biomarker for BD. First, we carried out a systematic review of the literature selecting those papers that evaluated MDA levels in BD. Then, we performed two separate meta-analyses: one of the studies that compared healthy controls (HC) with unmedicated BD and one with the studies that assessed MDA levels before and after treatment in BD, showing that bipolar patients experience more oxidative stress than healthy subjects and that treatment is effective in reducing MDA levels. In the first set of studies, we also explored through a meta-regression whether age, gender and experiencing an episode specifically influenced the difference between BD and HC in MDA levels. Bipolar patients compared to healthy subjects had higher MDA levels (SMD: 0.94, 95% CI: 0.23-1.64). Age (p < 0.01), gender (p < 0.01) and the presence of a current mood episode (p < 0.01) significantly influenced MDA plasma/serum levels. Specifically, studies that included more female, older subjects and more BD in euthymia were more likely to have higher MDA levels. Finally, patients after treatment had lower levels of MDA compared to baseline (SMD: -0.52, 95% CI: -0.85 -0.19). More studies are needed to draw definitive conclusions.

Comparison of Serum Uric Acid in Major Depressive Disorder and Bipolar Disorder: a Retrospective Chart Review Study

BACKGROUND

Uric acid (UA) has been suggested as a possible biomarker of bipolar disorder (BD) in recent studies. We aimed to provide a clearer comparison of UA levels between BD and major depressive disorder (MDD).

METHODS

We retrospectively reviewed the medical chart records of psychiatric inpatients aged 19-60 years, whose main discharge diagnoses were either MDD or BD, with an admission between January 1, 2015 and December 31, 2018 at Seoul National University Hospital. Data such as sex, age, body mass index (BMI), medication usage, and serum UA levels were extracted. Patients with medical conditions or on medications that could influence UA levels were excluded. Age, sex, BMI, and psychiatric drug usage were considered in the comparison of serum UA between MDD and BD patients.

RESULTS

Our sample consisted of 142 MDD patients and 234 BD patients. The BD patients had significantly higher serum UA levels compared to the MDD patients, without accounting for other confounding variables (5.75 ± 1.56 mg/dL vs. 5.29 ± 1.59 mg/dL, P = 0.006). T-test comparisons between psychiatric medication users and non-users revealed that mood stabilizers and antipsychotics may be relevant confounding factors in our sample analysis. The likelihood of BD diagnosis was significantly correlated with higher UA levels (odds ratio, 1.410; 95% confidence interval, 1.150-1.728; P = 0.001) when accounting for sex, age, and BMI in the logistic regression analysis. Also, accounting for mood stabilizers or antipsychotics, the likelihood of BD diagnosis was still significantly correlated with higher UA levels.

CONCLUSION

Our study confirms that BD patients are significantly more likely to show higher serum UA levels than MDD patients. The high UA levels in BD point to purinergic dysfunction as an underlying mechanism that distinguishes BD from MDD. Further research is recommended to determine whether UA is a trait or a state marker and whether UA correlates with the symptoms and severity of BD.

Patients With Drug-Naive Bipolar Disorder in Remission After 8 Weeks of Treatment Had Decreased Serum Uric Acid Concentrations

Background: Evidence indicates that the serum concentration of uric acid (UA) in patients may relate both to the pathophysiology and therapeutics of bipolar disorder (BPD). The purpose of this study was to examine the changes and clinical significance of serum UA concentrations in first-episode manic patients suffering from BPD. Methods: Seventy-six drug-naive patients with first-episode bipolar mania and 76 age- and gender-matched healthy subjects were recruited. Young Mania Rating Scale and Hamilton Depression Rating Scale were used to assess clinical symptoms. We tested serum UA concentrations by sandwich enzyme-linked immunosorbent assay at baseline and at the end of 8-week treatment in BPD patients and in the control group. Results: After 8-week quetiapine and sodium valproate treatment, this study revealed that the serum UA concentrations in remitted patients were significantly lower than nonremitted patients; however, those remitted patients still had higher serum UA than healthy controls. We discovered that the baseline UA concentration was higher in nonremitted than remitted patients after 8 weeks of treatment. Finally, a positive association was found between serum UA and symptom relief in the first episode of manic disorder patients. Conclusion: Patients with first-episode BPD had high levels of serum UA, which responds to treatment mainly in remitted patients. Our results suggest that serum UA concentrations might present potentially a trait marker in bipolar patients.