Brain Gene Expression-DNA Methylation Correlation in Suicide Completers: Preliminary Results

Abstract Background: Gene expression alterations have been implicated in suicide pathology. However, the study of the regulatory effect of DNA methylation on gene expression in the suicidal brain has been restricted to candidate genes. Objective: The objective of the study was to identify genes whose expression levels are correlated with DNA methylation in the prefrontal cortex of suicides. Methods: Postmortem prefrontal cortex samples from 21 suicides and six non-suicides were collected. Transcriptomic and DNA methylation profiles were evaluated with microarrays; cis correlations between gene expression and CpG methylation were screened. We then analyzed the presence of transcription factor (TF) binding sites (TFBS) at CpG sites correlated with gene expression. Gene expression of TFs involved in neurodevelopmental binding to predicted TFBS was determined in the BrainSpan database. Results: We identified 22 CpG sites whose methylation levels correlated with gene expression in the prefrontal cortex of suicides. Genes annotated to identified CpG sites were involved in neurodevelopment (BBS4, NKX6-2, AXL, CTNND1, and MBP) and polyamine metabolism (polyamine oxidase [PAOX]). Such correlations were not detected in the non-suicide group. Nine TFs (USF1, TBP, SF1, NRF1, RFX1, SP3, PKNOX1, MAZ, and POU3F2) showed differential expression in pre- and post-natal developmental periods, according to BrainSpan database. Conclusions: The integration of different omic technologies provided novel candidates for the investigation of genes whose expression is altered in the suicidal brain and their potential regulatory mechanisms. (REV INVEST CLIN. 2020;72(5):283-92)

Shortened telomere length in bipolar disorder: a comparison of the early and late stages of disease

Objective: Bipolar disorder (BD) has been associated with increased rates of age-related diseases, such as type II diabetes, metabolic syndrome, osteoporosis, and cardiovascular disorders. Several biological findings have been associated with age-related disorders, including increased oxidative stress, inflammation, and telomere shortening. The objective of this study was to compare telomere length among participants with BD at early and late stages and age- and gender-matched healthy controls. Methods: Twenty-six euthymic subjects with BD and 34 healthy controls were recruited. Genomic DNA was extracted from peripheral blood and mean telomere length was measured using real-time quantitative polymerase chain reaction. Results: Telomere length was significantly shorter in both the early and late subgroups of BD subjects when compared to the respective controls (p = 0.002 and p = 0.005, respectively). The sample size prevented additional subgroup analyses, including potential effects of medication, smoking status, and lifestyle. Conclusion: This study is concordant with previous evidence of telomere shortening in BD, in both early and late stages of the disorder, and supports the notion of accelerated aging in BD.

Cognition and functioning in bipolar depression

Objectives: Depressive symptoms are associated with worse outcomes in patients with bipolar disorder (BD). However, scarce data are available regarding neurocognitive profiles across different areas of functioning among BD patients with moderate and severe depression. Our objective was to assess cognition and global functioning in a group of patients with bipolar depression. Methods: Data were available for 100 patients with bipolar depression (78% female) and 70 controls (64% female) paired by age and education level. Cognitive function was assessed with a neuropsychological test battery. Functioning was assessed with the Functioning Assessment Short Test. Results: In patients, severe depression was associated with poorer cognitive performance on measures of executive function. Patients with severe depression showed worse global functioning than those with moderate depression (z = 2.54, p = 0.011). In patients with severe depression, lower global functioning was associated with lower scores in working memory (r = -0.200, p = 0.010), and executive function (r = -0.210, p = 0.007; and r = 0.293, p < 0.001). Conclusion: Our findings suggest cognitive impairment and global functioning impairment are associated with the severity of depressive symptoms in bipolar depression. Intensive treatment of depressive symptoms in patients with BD is crucial to improve cognitive functioning and, consequently, functional outcomes.

Marcadores periféricos e a fisiopatologia do transtorno bipolar / Peripheral markers and the pathophysiology of bipolar disorder

INTRODUÇÃO: O entendimento da fisiopatologia do transtorno bipolar vem tendo avanços consistentes nos últimos anos. Um enfoque na relação entre carga alostática e alterações sistêmicas vem tomando corpo, com o objetivo de se entender a frequente progressão da doença. Proeminentes entre os mediadores periféricos têm sido as moléculas que poderiam ser amplamente agrupadas em neurotrofinas, marcadores de estresse oxidativo e marcadores inflamatórios. OBJETIVO: Descrever achados recentes em relação à fisiopatologia sistêmica do transtorno bipolar, com enfoque especial em estudos brasileiros, tentando articular uma visão coerente do conhecimento atual do campo. MÉTODO: Revisão narrativa da literatura relacionada a neurotrofinas, estresse oxidativo e marcadores inflamatórios no transtorno bipolar. RESULTADOS: Diversas fontes de evidência, provenientes tanto de estudos pré-clínicos quanto clínicos, revelam consistentemente alterações sistêmicas no transtorno bipolar. Os achados são especialmente robustos em pacientes com múltiplos episódios. Nesses, alterações relacionadas a episódios de mania e depressão são notáveis em neurotrofinas e dano oxidativo a lipídeos. Um número menor de estudos mostra alterações no sistema imune, em particular estados pró-inflamatórios. CONCLUSÃO: Alterações sistêmicas que correlacionam o transtorno bipolar a comorbidade clínica, disfunção cognitiva, incapacidade e mortalidade precoce começam a ser traçadas. Estudos envolvendo desenhos longitudinais, amostras populacionais e ensaios clínicos envolvendo marcadores periféricos devem ser incorporados no futuro próximo e reforçar a validade de uma noção de envolvimento multissistêmico no transtorno bipolar.

INTRODUCTION: The understanding of the pathophysiology of bipolar disorder has steadily advanced in the past few years. Thereby, a focus on allostatic load and systemic changes has appeared, with the aim to understand illness progression. Amongst the peripheral markers, molecules that can be widely classified into neurotrophins, oxidadive stress markers, and inflammation markers have been elevated. OBJECTIVE: To describe recent findings regarding the systemic pathophysiology of bipolar disorder, with a special focus on Brazilian studies and to create a coherent view of the current knowledge in the field. METHOD: Narrative review of the literature regarding neurotrophins, oxidative stress, and inflammatory markers in bipolar disorder. RESULTS: A diverse body of evidence, based on both pre-clinical and clinical studies, reveals consistent systemic changes in bipolar disorder. The findings are particularly robust in patients after multiple episodes. Thereby, remarkable changes related to manic and depressive episodes were found in neurotrophins and oxidative damage to lipids. Regarding to immune system alterations, in particular pro-inflammatory states, the literature is less consistent. DISCUSSION: Systemic changes that link bipolar disorder to clinical comorbidity, cognitive dysfunction, disability and early mortality are becoming evident. In the near future, longitudinal studies with population-based samples and clinical trials incorporating biomarkers are needed to shed light upon the notion of a multisystem involvement in bipolar disorder.

Decreased BDNF levels in amygdala and hippocampus after intracerebroventricular administration of ouabain / Diminuição dos níveis de BDNF em amígdala e hipocampo após a administração intracerebroventricular de ouabaína

OBJECTIVE: The present study aims to investigate the effects of ouabain intracerebroventricular injection on BDNF levels in the amygdala and hippocampus of Wistar rats.METHODS: Animals received a single intracerebroventricular injection of ouabain (10-3 and 10-2 M) or artificial cerebrospinal fluid and immediately, 1h, 24h, or seven days after injection, BDNF levels were measured in the rat's amygdala and hippocampus by sandwich-ELISA (n = 8 animals per group).RESULTS: When evaluated immediately, 3h, or 24h after injection, ouabain in doses of 10-2 and 10-3 M does not alter BDNF levels in the amygdala and hippocampus. However, when evaluated seven days after injection, ouabain in 10-2 and 10-3 M, showed a significant reduction in BDNF levels in both brain regions evaluated.DISCUSSION: In conclusion, we propose that the ouabain decreased BDNF levels in the hippocampus and amygdala when assessed seven days after administration, supporting the Na/K ATPase hypothesis for bipolar illness.

OBJETIVO: O presente estudo tem como objetivo investigar os efeitos da injeção intracerebroventricular de ouabaína sobre os níveis de BDNF na amígdala e no hipocampo de ratos Wistar.MÉTODOS: Os animais receberam uma única injeção intracerebroventricular de ouabaína (10-3 and 10-2 M) ou fluido cerebroespinhal artificial e, imediatamente, 3h, 24h ou sete dias após a injeção, os níveis de BDNF foram mensurados na amígdala e hipocampo dos ratos por ELISA sandwich (n = 8 animais por grupo).RESULTADOS: Quando avaliados imediatamente após a injeção, 3h ou 24h, ouabaína nas doses 10-2 e 10-3 M não alterou os níveis de BDNF em ambas as estruturas avaliadas. Entretanto, quando avaliados sete dias após a injeção, ouabaína nas doses 10-2 e 10-3 M mostrou uma significante redução nos níveis de BDNF em amígdala e hipocampo.CONCLUSÃO: Em conclusão, propõe-se que a administração de ouabaína diminuiu os níveis de BDNF em amígdala e hipocampo quando avaliados sete dias após a injeção, suportando a hipótese da participação da Na/K ATPase no transtorno bipolar.