The Emerging Neurobiology of Bipolar Disorder

Alternations of Plasma Fatty Acids in Patients With Bipolar Depression Under Acute Treatment of rTMS Combined With Quetiapine and Mood Stabilizer

PURPOSE

Repetitive transcranial magnetic stimulation (rTMS) represents a potential clinical tool in treating bipolar disorder (BD). However, the intervention of rTMS combined with pharmacotherapy on the plasma fatty acids (FAs) in patients with bipolar depression has not been reported yet.

METHOD

In this study, we assessed the clinical symptoms and evaluated plasma FAs from 30 inpatients with bipolar depression at baseline phase (BD group), after 2 weeks of treatment with rTMS combined with quetiapine and mood stabilizer (BD-2w group), and 32 healthy controls (HCs).

FINDING

We found that acetic acid, propionic acid, isovaleric acid, isobutyric acid, and valeric acid, as well as levels of total short-chain fatty acids (SCFAs), were decreased in both BD and BD-2w groups, and levels of several medium- and long-chain fatty acids (MLCFAs) were altered in BD when compared with HC. Moreover, 2 weeks of treatment increased the levels of various MLCFAs. Finally, we developed combinational FAs panels that could distinguish BD from HC (area under the curve [AUC] = 0.961), BD-2w from HC (AUC = 0.978), and BD from BD-2w (AUC = 0.891) effectively.

CONCLUSION

These findings might provide a basis for developing diagnostic methods and reveal the potential relationship between bipolar depression and plasma FAs.

Comprehensive bibliometric analysis of pharmacotherapy for bipolar disorders: Present trends and future directions

BACKGROUND

Bipolar disorder (BD) is a severe mental illness characterized by significant mood swings. Effective drug treatment modalities are crucial for managing BD.

AIM

To analyze the current status and future trends of global research on BD drug treatment over the last decade.

METHODS

The Web of Science Core Collection database spanning from 2015 to 2024 was utilized to retrieve literature related to BD drug treatment. A total of 2624 articles were extracted. Data visualization and analysis were conducted using CiteSpace, VOSviewer, Pajek, Scimago Graphica, and R-studio bibliometrix to identify research hotspots, key contributors, and future trends.

RESULTS

The United States, China, and the United Kingdom have made the most significant contributions to research on BD drug treatment and formed notable research collaboration networks. The University of Pittsburgh, Massachusetts General Hospital, and the University of Michigan have been identified as the major research institutions in this field. The Journal of Affective Disorders is the most influential journal. A keyword analysis revealed research hotspots related to clinical symptoms, drug efficacy, and genetic mechanisms. A citation analysis identified the management guidelines published by Yatham et al in 2018 as the most cited paper.

CONCLUSION

This study provides a detailed overview of the field of BD drug treatment, highlighting key contributors, research hotspots, and future directions. The study findings can be employed as a reference for future research and policymaking, which may enable further development and optimization of BD pharmacotherapy.

Two hub genes of bipolar disorder, a bioinformatics study based on the GEO database

Bipolar disorder is a mood illness that affects many people. It has a high recurrence frequency and will cause significant damage to the patient's social function. At present, the pathogenesis of BD is not clear. The National Center for Biotechnology Information (NCBI) established and maintained the Gene Expression Omnibus (GEO) database, a gene expression database. For bioinformatics analysis, researchers can obtain expression data from the internet. At present, the samples of the dataset used in the research of BD are mostly from brain tissue, and the data containing blood samples are rarely used. GEO databases (GSE46416, GSE5388, and GSE5389) were used to retrieve public data, and utilizing the online tool GEO2R, differentially expressed genes (DEGs) were retrieved. The common DEGs between the samples of patients with BD and the samples of the normal population were screened by Venn diagrams. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to perform functional annotation and pathway enrichment analysis of DEGs. A protein-protein interaction network (PPI) was built to investigate hub genes on this basis. There were 117 up-regulated DEGs and 38 down-regulated DEGs discovered, with two hub genes [SRC, CDKN1A] among the up-regulated DEGs. These two hub genes were also highly enriched in the oxytocin signaling pathway, proteoglycans in cancer and bladder cancer, according to KEGG analysis. The results of the receiver operating characteristic curve (ROC) of SRC and CDKN1A in the three datasets strongly suggested that SRC and CDKN1A were potential diagnostic markers of BD. The results strongly suggest that SRC and CDKN1A are related to the pathogenesis of BD.

Transient splenial lesion syndrome in bipolar-II disorder: a case report highlighting reversible brain changes during hypomanic episodes

Background

Reversible splenial lesion syndrome (RESLES) is a rare neurological condition characterized by temporary abnormalities in the splenium of the corpus callosum, which has been reported in mental disorders. Previous studies on bipolar disorder (BD) primarily focused on aspects such as brain structure and function, neurochemical changes, and genetics. However, there have been no studies reporting the occurrence of this syndrome during hypomanic episodes and its disappearance during the remission phase in bipolar disorder type 2 (BD-II).

Case presentation

We present a case report of a 30 years-old female patient with BD-II who exhibited symptoms of RESLES during a hypomanic episode. The patient, with a 12 years psychiatric history, has experienced recurrent depressive episodes initially, with the first hypomanic episode occurring 8 years ago. During this period, this patient made several visits to the outpatient clinic to have her medications adjusted due to repeated suicide attempts. This time, she was admitted to our hospital with a second hypomanic episode due to drug withdrawal during pregnancy. The RESLES was observed on her brain magnetic resonance image, and it was alleviated after treatment with lithium carbonate and quetiapine until achieving remission.

Conclusion

We present the first report of identifying RESLES in BD-II with hypomanic episodes, which subsequently disappears during the remission phase. Our case report highlights a potential association between BD and RESLES, emphasizing the need for future studies to explore the underlying mechanisms connecting these two conditions in greater depth.

A gene expression analysis of long non-coding RNAs NKILA and PACER as well as their target genes, NF-κB and cox-2 in bipolar disorder patients

Bipolar disorder (BD) is a severe condition characterized by periods of mania and depression. Despite advances in the neurobiology of bipolar disorder, the exact etiology of the disease remains unclear. There is evidence that Inflammation is associated with bipolar disorder. COX-2 and NF-κB are two critical mediators in the inflammatory pathways. Long non-coding RNAs (lncRNAs) are a new class of non-coding RNAs that play a wide range of roles, especially in developing and maintaining normal brain functions. Two lncRNAs called PACER and NKILA control the expression of COX-2 and NF-κB genes, respectively. In this study, Expression levels of PACER and NKILA lncRNAs, as well as, COX-2 and NF-κB genes were measured in fifty patients with bipolar disorder and 50 healthy individuals by real-time PCR. Expression levels of NKILA and COX2 were considerably reduced in BD patients compared with healthy controls. Such significant downregulation in the expression of NKILA and PACER was only observed in male patients with BD compared with male healthy subjects. Also, according to the results of the ROC curve, the area under curve values for NKILA and COX2 were 0.68 and 0.52 respectively. Consequently, the NKILA gene could be considered a biomarker. By examining the degree of pairwise correlation between genes, all genes had a significant positive correlation with each other. Taken together, these results revealed a function for NKILA and PACER lncRNAs in the pathogenesis of BD.

Shared and distinct patterns of dynamical degree centrality in bipolar disorder across different mood states

BACKGROUND

Previous studies have probed the brain static activity pattern in bipolar disorder across different states. However, human intrinsic brain activity is time-varying and dynamic. There is a lack of knowledge about the brain dynamical pattern in bipolar disorder across different mood states.

METHODS

This study used the dynamical degree centrality (dDC) to investigate the resting-state whole-brain dynamical pattern voxel-wise in a total of 62 bipolar disorder [28 bipolar depression (BD), 13 bipolar mania (BM), 21 bipolar euthymia (BE)], and 30 healthy controls (HCs). One-way analysis of variance (ANOVA) was applied to explore the omnibus differences of the dDC pattern across all groups, and Pearson's correlation analysis was used to evaluate the relationship between the dDC variability in detected regions with clinical symptom severity.

RESULTS

One-way ANOVA analysis showed the omnibus differences in the left inferior parietal lobule/middle occipital gyrus (IPL/MOG) and right precuneus/posterior cingulate cortex (PCUN/PCC) across all groups. The post hoc analysis revealed that BD showed decreased dDC in the IPL/MOG compared with all other groups, and both BD and BM exhibited decreased dDC in the PCUN/PCC compared with BE and HCs. Furthermore, correlation analysis showed that the dDC variability of the IPL/MOG and PCUN/PCC negatively correlated with the depression symptom levels in all patients with bipolar disorder.

CONCLUSION

This study demonstrated the distinct and shared brain dynamical pattern of the depressive, manic, and euthymia states. Our findings provide new insights into the pathophysiology of bipolar disorder across different mood states from the dynamical brain network pattern perspective.

Functional genomic analysis delineates regulatory mechanisms of GWAS-identified bipolar disorder risk variants

BACKGROUND

Genome-wide association studies (GWASs) have identified multiple risk loci for bipolar disorder (BD). However, pinpointing functional (or causal) variants in the reported risk loci and elucidating their regulatory mechanisms remain challenging.

METHODS

We first integrated chromatin immunoprecipitation sequencing (ChIP-Seq) data from human brain tissues (or neuronal cell lines) and position weight matrix (PWM) data to identify functional single-nucleotide polymorphisms (SNPs). Then, we verified the regulatory effects of these transcription factor (TF) binding-disrupting SNPs (hereafter referred to as "functional SNPs") through a series of experiments, including reporter gene assays, allele-specific expression (ASE) analysis, TF knockdown, CRISPR/Cas9-mediated genome editing, and expression quantitative trait loci (eQTL) analysis. Finally, we overexpressed PACS1 (whose expression was most significantly associated with the identified functional SNPs rs10896081 and rs3862386) in mouse primary cortical neurons to investigate if PACS1 affects dendritic spine density.

RESULTS

We identified 16 functional SNPs (in 9 risk loci); these functional SNPs disrupted the binding of 7 TFs, for example, CTCF and REST binding was frequently disrupted. We then identified the potential target genes whose expression in the human brain was regulated by these functional SNPs through eQTL analysis. Of note, we showed dysregulation of some target genes of the identified TF binding-disrupting SNPs in BD patients compared with controls, and overexpression of PACS1 reduced the density of dendritic spines, revealing the possible biological mechanisms of these functional SNPs in BD.

CONCLUSIONS

Our study identifies functional SNPs in some reported risk loci and sheds light on the regulatory mechanisms of BD risk variants. Further functional characterization and mechanistic studies of these functional SNPs and candidate genes will help to elucidate BD pathogenesis and develop new therapeutic approaches and drugs.

Translating big data to better treatment in bipolar disorder - a manifesto for coordinated action

Bipolar disorder (BD) is a major healthcare and socio-economic challenge. Despite its substantial burden on society, the research activity in BD is much smaller than its economic impact appears to demand. There is a consensus that the accurate identification of the underlying pathophysiology for BD is fundamental to realize major health benefits through better treatment and preventive regimens. However, to achieve these goals requires coordinated action and innovative approaches to boost the discovery of the neurobiological underpinnings of BD, and rapid translation of research findings into development and testing of better and more specific treatments. To this end, we here propose that only a large-scale coordinated action can be successful in integrating international big-data approaches with real-world clinical interventions. This could be achieved through the creation of a Global Bipolar Disorder Foundation, which could bring government, industry and philanthropy together in common cause. A global initiative for BD research would come at a highly opportune time given the seminal advances promised for our understanding of the genetic and brain basis of the disease and the obvious areas of unmet clinical need. Such an endeavour would embrace the principles of open science and see the strong involvement of user groups and integration of dissemination and public involvement with the research programs. We believe the time is right for a step change in our approach to understanding, treating and even preventing BD effectively.