Toward stratified treatments for bipolar disorders

Integrated proteomic and genomic analysis to identify predictive biomarkers for valproate response in bipolar disorder: a 6-month follow-up study

BACKGROUND

Several genetic studies have been undertaken to elucidate the intricate interplay between genetics and drug responses in bipolar disorder (BD). However, there has been notably limited research on biomarkers specifically linked to valproate, with only a few studies investigating integrated proteomic and genomic factors in response to valproate treatment. Therefore, this study aimed to identify biological markers for the therapeutic response to valproate treatment in BD. Patients with BD in remission were assessed only at baseline, whereas those experiencing acute mood episodes were evaluated at three points (baseline, 8 ± 2 weeks, and 6 ± 1 months). The response to valproate treatment was measured using the Alda scale, with individuals scoring an Alda A score ≥ 5 categorized into the acute-valproate responder (acute-VPAR) group. We analyzed 158 peptides (92 proteins) from peripheral blood samples using multiple reaction monitoring mass spectrometry, and proteomic result-guided candidate gene association analyses, with 1,627 single nucleotide variants (SNVs), were performed using the Korean chip.

RESULTS

The markers of 37 peptides (27 protein) showed temporal upregulation, indicating possible association with response to valproate treatment. A total of 58 SNVs in 22 genes and 37 SNVs in 16 genes showed nominally significant associations with the Alda A continuous score and the acute-VPAR group, respectively. No SNVs reached the genome-wide significance threshold; however, three SNVs (rs115788299, rs11563197, and rs117669164) in the secreted phosphoprotein 2 gene reached a gene-based false discovery rate-corrected significance threshold with response to valproate treatment. Significant markers were associated with the pathophysiological processes of bipolar disorders, including the immune response, acute phase reaction, and coagulation cascade. These results suggest that valproate effectively suppresses mechanisms associated with disease progression.

CONCLUSIONS

The markers identified in this study could be valuable indicators of the underlying mechanisms associated with response to valproate treatment.

Variation in rostral anterior cingulate functional connectivity with amygdala and caudate during first manic episode distinguish bipolar young adults who do not remit following treatment

OBJECTIVES

Altered activity in the ventrolateral prefrontal and anterior cingulate cortices, as well as subcortical and amygdala projection sites, was previously reported during a first manic episode in youth with bipolar disorder and observed to be associated with treatment response. To extend these findings, we investigated functional connectivity among these regions in first-episode manic participants who remitted after 8 weeks of treatment compared to those who did not.

METHODS

Forty-two participants with bipolar disorder (60% female) during their first manic episode were recruited and received 8 weeks of treatment. Twenty-one remitted following treatment. Participants completed fMRI scans, at baseline and following 8 weeks of treatment, while performing a continuous performance task with emotional and neutral distractors. A healthy comparison group (n = 41) received fMRI evaluations at the same intervals. Differences in functional connectivity of the amygdala and caudate with the rostral anterior cingulate and ventrolateral prefrontal cortices at baseline (and changes in functional connectivity following treatment) were modeled between groups.

RESULTS

At baseline, non-remitters showed an increase in positive connectivity between right anterior cingulate and caudate and a loss of negative connectivity between right anterior cingulate and amygdala, compared to healthy participants. Individuals who remitted following treatment showed an increase in negative connectivity between amygdala and left anterior cingulate 8 weeks following treatment.

CONCLUSIONS

Results provide evidence of alterations in anterior cingulate amygdala and caudate functional connectivity in bipolar disorder non-remitters during a first manic episode and changes in anterior cingulate functional connectivity associated with remission suggesting targets to predict treatment response. Registered at ClinicalTrials.Gov; Functional and Neurochemical Brain Changes in First-episode Bipolar Mania. NCT00609193. URL: https://clinicaltrials.gov/ct2/show/NCT00609193?term=strakowskirank=1.

The black sheep of the family- whole-exome sequencing in family of lithium response discordant bipolar monozygotic twins

Twin studies are among the most promising strategies for studying heritable disorders, including bipolar disorder (BD). The aim of the present study was to identify distinguishing genes between monozygotic (MZ) twins with different BD phenotype and compare them to their non-affected siblings. Whole-exome sequencing (WES) can identify rare and structural variants that could detect the polygenetic burden of complex disorders. WES was performed on a family composed of two MZ twins with BD, their unaffected brother and unaffected parents. The twins have a discordant response to lithium and distinct course of illness. Following WES, six genes of particular interest emerged: Neurofibromin type 1 (NF1), Biorientation of chromosomes in cell division 1 (BOD1), Golgi-associated gamma adaptin ear-containing ARF binding protein 3 (GGA3), Disrupted in schizophrenia 1 (DISC1), Neuromedin U receptor 2 (NMUR2), and Huntingtin interacting protein 1-related (HIP1R). Interestingly, many of these influence glutamatergic pathways and thus the findings may have therapeutical implications. These results may provide important insights to unveil genetic underpinnings of BD and the response to lithium.

Gray matter voxel-based morphometry in mania and remission states of children with bipolar disorder

BACKGROUND

It has been found by many studies that gray matter (GM) abnormalities exist in both adults and children with bipolar disorder (PBD) which is a serious mental illness characterized by alternating episodes of mania and depression. However, there are few studies on the comparison between brain imaging of different mood states shown by patients with bipolar disorder. This study is aimed at exploring the differences existing in brain structures between children with bipolar disorder and that of healthy controls, and then it tries to further explore whether there is a structural difference between the states of mania and remission in children with bipolar disorder.

METHODS

21 PBD-mania subjects, 19 PBD-remission subjects and 18 control subjects aged 12-17 years old were engaged in this study. In the present study, magnetic resonance imaging was obtained by employing a Siemens 3.0 T scanner. With regard to the volumes of gray matter in the mania group, remission group and healthy control group, analysis was carried out by using voxel-based morphometry (VBM). Further analysis was conducted on the correlation between MRI data and clinical features of patients with PBD.

RESULTS

In comparison with the healthy control subjects, the gray matter volume measured from the left hippocampus, parahippocampal gyrus and amygdala in both manic and euthymic groups showed a decreasing trend, while the volume of left orbitofrontal cortex increased. However, no significant difference in volumes was found between BD manic and euthymic groups. It was observed that the volume of orbitofrontal cortex had a positive correlation with onset age in PBD euthymic group.

CONCLUSIONS

Our study came to the conclusion that extensive brain structural changes are available in patients with PBD. The brain regions with structural changes are distributed in the anterior limbic network (ALN), which has been proved to have been involved in the abnormal emotional and cognitive regulation of PBD. However, there is no difference in the volumes of gray matter between mania and remission in PBD .

Personalized and precision medicine as informants for treatment management of bipolar disorder

DSM-5 diagnostic categories, defined by a set of psychopathological symptoms are heterogeneous conditions that may include different biological entities, with distinct etiopathogenesis, different courses and requiring different treatment management. For bipolar disorder the major evidences for this lack of validity are the long paths before a proper diagnosis, the inconsistence of treatment guidelines, the long phases of pharmacological adjustment and the low average of long-term treatment response rates. Personalized medicine for mental disorders aims to couple established clinical-pathological indexes with new molecular profiling to create diagnostic, prognostic and therapeutic strategies precisely tailored to each patient. Regarding bipolar disorder, the clinical history and presentation are still the most reliable markers in stratifying patients and guiding therapeutic management, despite the research goes to great lengths to develop new neuropsychological or biological markers that can reliably predict individual therapy effectiveness. We provide an overview of the advancements in personalized medicine in bipolar disorder, with particular attention to how psychopathology, age at onset, comorbidity, course and staging, genetic and epigenetic, imaging and biomarkers can influence treatment management and provide an integration to the conventional treatment guidelines. This approach may offer a new and rational path for the development of treatments for targeted subgroups of patients with bipolar disorder.

Individual responses of rodents in modelling of affective disorders and in their treatment: prospective review

IntroductionLack of good animal models for affective disorders, including major depression and bipolar disorder, is noted as a major bottleneck in attempts to study these disorders and develop better treatments. We suggest that an important approach that can help in the development and use of better models is attention to variability between model animals. RESULTS: Differences between mice strains were studied for some decades now, and sex differences get more attention than in the past. It is suggested that one factor that is mostly neglected, individual variability within groups, should get much more attention. The importance of individual differences in behavioral biology and ecology was repeatedly mentioned but its application to models of affective illness or to the study of drug response was not heavily studied. The standard approach is to overcome variability by standardization and by increasing the number of animals per group. CONCLUSIONS: Possibly, the individuality of specific animals and their unique responses to a variety of stimuli and drugs, can be helpful in deciphering the underlying biology of affective behaviors as well as offer better prediction of drug responses in patients.

Can an Integrated Science Approach to Precision Medicine Research Improve Lithium Treatment in Bipolar Disorders?

Clinical practice guidelines identify lithium as a first line treatment for mood stabilization and reduction of suicidality in bipolar disorders (BD); however, most individuals show sub-optimal response. Identifying biomarkers for lithium response could enable personalization of treatment and refine criteria for stratification of BD cases into treatment-relevant subgroups. Existing systematic reviews identify potential biomarkers of lithium response, but none directly address the conceptual issues that need to be addressed to enhance translation of research into precision prescribing of lithium. For example, although clinical syndrome subtyping of BD has not led to customized individual treatments, we emphasize the importance of assessing clinical response phenotypes in biomarker research. Also, we highlight the need to give greater consideration to the quality of prospective longitudinal monitoring of illness activity and the differentiation of non-response from partial or non-adherence with medication. It is unlikely that there is a single biomarker for lithium response or tolerability, so this review argues that more research should be directed toward the exploration of biosignatures. Importantly, we emphasize that an integrative science approach may improve the likelihood of discovering the optimal combination of clinical factors and multimodal biomarkers (e.g., blood omics, neuroimaging, and actigraphy derived-markers). This strategy could uncover a valid lithium response phenotype and facilitate development of a composite prediction algorithm. Lastly, this narrative review discusses how these strategies could improve eligibility criteria for lithium treatment in BD, and highlights barriers to translation to clinical practice including the often-overlooked issue of the cost-effectiveness of introducing biomarker tests in psychiatry.

Structural characteristics of the brain reward circuit regions in patients with bipolar I disorder: A voxel-based morphometric study

Bipolar I disorder (BD-I) is often misdiagnosed, leading to inadequate treatment and significant disability along with reduced quality of life. Recent neural models suggest that the reward circuitry is affected in bipolar disorder. The purpose of the present study was to identify structural abnormalities in the brain reward-processing neural circuitry among patients with BD-I. 21 patients with BD-I and 21 healthy controls (HC) participated in this study. Structural magnetic resonance imaging was performed. Region-of-interest (ROI) voxel-based morphometry analysis was applied to assess the presence of structural changes between the BD-I patient group and the control group. The results of the reward circuitry ROI analysis revealed lower gray matter volumes in the left ventromedial prefrontal cortex (VMPFC), left dorsomedial prefrontal cortex (DMPFC), and left ventrolateral prefrontal cortex (VLPFC) in patients with BD-I compared to HC. Our results suggest that abnormalities in the brain reward-processing neural circuitry, especially those in the left VMPFC, left DMPFC, and left VLPFC, may play an important role in the pathophysiology of BD-I.

Innovative approaches to bipolar disorder and its treatment

All psychiatric disorders have suffered from a dearth of truly novel pharmacological interventions. In bipolar disorder, lithium remains a mainstay of treatment, six decades since its effects were serendipitously discovered. The lack of progress reflects several factors, including ignorance of the disorder's pathophysiology and the complexities of the clinical phenotype. After reviewing the current status, we discuss some ways forward. First, we highlight the need for a richer characterization of the clinical profile, facilitated by novel devices and new forms of data capture and analysis; such data are already promoting a reevaluation of the phenotype, with an emphasis on mood instability rather than on discrete clinical episodes. Second, experimental medicine can provide early indications of target engagement and therapeutic response, reducing the time, cost, and risk involved in evaluating potential mood stabilizers. Third, genomic data can inform target identification and validation, such as the increasing evidence for involvement of calcium channel genes in bipolar disorder. Finally, new methods and models relevant to bipolar disorder, including stem cells and genetically modified mice, are being used to study key pathways and drug effects. A combination of these approaches has real potential to break the impasse and deliver genuinely new treatments.

Personalized medicine in psychiatry

BACKGROUND

Personalized medicine is a model in which a patient's unique clinical, genetic, and environmental characteristics are the basis for treatment and prevention. Aim, method, and results: This review aims to describe the current tools, phenomenological features, clinical risk factors, and biomarkers used to provide personalized medicine. Furthermore, this study describes the target areas in which they can be applied including diagnostics, treatment selection and response, assessment of risk of side-effects, and prevention.

DISCUSSION AND CONCLUSION

Personalized medicine in psychiatry is challenged by the current taxonomy, where the diagnostic categories are broad and great biological heterogeneity exists within each category. There is, thus, a gap between the current advanced research prospects and clinical practice, and the current taxonomy is, thus, a poor basis for biological research. The discussion proposes possible solutions to narrow this gap and to move psychiatric research forward towards personalized medicine.

Can neuroimaging disentangle bipolar disorder?

BACKGROUND

Bipolar disorder heterogeneity is large, leading to difficulties in identifying neuropathophysiological and etiological mechanisms and hindering the formation of clinically homogeneous patient groups in clinical trials. Identifying markers of clinically more homogeneous groups would help disentangle BD heterogeneity. Neuroimaging may aid in identifying such groups by highlighting specific biomarkers of BD subtypes or clinical dimensions.

METHODS

We performed a systematic literature search of the neuroimaging literature assessing biomarkers of relevant BD phenotypes (type-I vs. II, presence vs. absence of psychotic features, suicidal behavior and impulsivity, rapid cycling, good vs. poor medication response, age at onset, cognitive performance and circadian abnormalities).

RESULTS

Consistent biomarkers were associated with suicidal behavior, i.e. frontal/anterior alterations (prefrontal and cingulate grey matter, prefrontal white matter) in patients with a history of suicide attempts; and with cognitive performance, i.e. involvement of frontal and temporal regions, superior and inferior longitudinal fasciculus, right thalamic radiation, and corpus callosum in executive dysfunctions. For the other dimensions and sub-types studied, no consistent biomarkers were identified.

LIMITATIONS

Studies were heterogeneous both in methodology and outcome.

CONCLUSIONS

Though theoretically promising, neuroimaging has not yet proven capable of disentangling subtypes and dimensions of bipolar disorder, due to high between-study heterogeneity. We issue recommendations for future studies.

Proteomics strategies for bipolar disorder evaluation: From sample preparation to validation

Bipolar disorder (BD) is a complex and costly psychiatric disorder, which affects one hundred million people worldwide. Due to its heterogeneity, correct BD diagnosis is still a challenge. In order to overcome this issue, different bioanalytical strategies have been proposed in the literature recently. Among these strategies, proteomic approaches have arisen as some of the most promising in the area. Thus, recent applications suggest protein profiles to further refine the proteome of BD as well as the discovery of novel protein biomarkers to facilitate diagnostics. In this review, the state-of-art of proteomic research in BD is summarized. Furthermore, important aspects of proteomics for understanding of BD, such as sample type and size, sampling, sample preparation, gel-based and gel-free proteomics, proteomic quantitative and protein validation are overviewed.

Smartphone Application for the Analysis of Prosodic Features in Running Speech with a Focus on Bipolar Disorders: System Performance Evaluation and Case Study

Bipolar disorder is one of the most common mood disorders characterized by large and invalidating mood swings. Several projects focus on the development of decision support systems that monitor and advise patients, as well as clinicians. Voice monitoring and speech signal analysis can be exploited to reach this goal. In this study, an Android application was designed for analyzing running speech using a smartphone device. The application can record audio samples and estimate speech fundamental frequency, F0, and its changes. F0-related features are estimated locally on the smartphone, with some advantages with respect to remote processing approaches in terms of privacy protection and reduced upload costs. The raw features can be sent to a central server and further processed. The quality of the audio recordings, algorithm reliability and performance of the overall system were evaluated in terms of voiced segment detection and features estimation. The results demonstrate that mean F0 from each voiced segment can be reliably estimated, thus describing prosodic features across the speech sample. Instead, features related to F0 variability within each voiced segment performed poorly. A case study performed on a bipolar patient is presented.

Bipolar disorder: Functional neuroimaging markers in relatives

Neural models of anatomical and functional alterations have been proposed for bipolar disorders (BD). However, studies in affected patients do not allow disentangling alterations linked to the liability to BD from those associated with the evolution, medication and comorbidities of BD. Explorations in high risk subjects allow the study of these risk markers. We reported and summarized all functional magnetic resonance imaging (fMRI) studies focusing on first-degree relatives of BD patients. We found 29 studies reporting neural correlates of working memory (WM), emotional processing, executive functions and resting state in relatives of BD patients, compared to healthy subjects. Overall, the same regions that have been involved in patients, such as the inferior frontal gyrus and limbic areas, seem to be functionally altered in high-risk subjects. We conclude that the same brain regions already implicated in the pathophysiology of the disease such as the amygdala are also associated with the risk of BD. However longitudinal studies are required to understand their implication in the transition to BD.

Theory of Mind in Bipolar Disorder, with Comparison to the Impairments Observed in Schizophrenia

Our ability to make sense of information on the potential intentions and dispositions of others is of paramount importance for understanding their communicative intent, and for judging what an appropriate reaction might be. Thus, anything that impinges on this ability has the potential to cause significant social impairment, and compromise an individual's level of functioning. Both bipolar disorder and schizophrenia are known to feature theory of mind impairment. We conducted a theoretical review to determine the extent and types of theory of mind impairment in bipolar disorder, and evaluate their relationship to medication and symptoms. We also considered possible mediatory mechanisms, and set out to discover what else could be learnt about the impairment in bipolar disorder by comparison to the profile of impairment in schizophrenia. The literature established that in bipolar disorder (i) some form of theory of mind impairment has been observed in all mood states, including euthymia, (ii) the form of theory of mind assessed and task used to make the assessment influence the impairment observed, and (iii) there might be some relationship to cognitive impairment, although a relationship to standard clinical variables was harder to establish. What also became clear in the literature on bipolar disorder itself was the possible relationship of theory of mind impairment to history of psychotic symptoms. Direct comparative studies, including patients with schizophrenia, were thus examined, and provided several important directions for future research on the bases of impairment in bipolar disorder. Particularly prominent was the issue of whether theory of mind impairment could be considered a candidate endophenotype for the psychoses, although current evidence suggests that this may be premature. The differences in impairment across schizophrenia and bipolar disorder may, however, have genuine differential effects on social functioning and the likely success of remediation.