The role of brain-derived neurotrophic factor in the pathophysiology of adolescent suicidal behavior

Omega-3 alleviates behavioral and molecular changes in a mouse model of stress-induced juvenile depression

Introduction

Depression is increasingly diagnosed in adolescence, necessitating specific prevention and treatment methods. However, there is a lack of animal models mimicking juvenile depression. This study explores a novel model using ultrasound (US) stress in juvenile mice.

Methods

We employed the US stress model in one-month-old C57/BL6 mice, exposing them to alternating ultrasound frequencies (20-25 kHz and 25-45 kHz) for three weeks. These frequencies correspond to negative and neutral emotional states in rodents and can induce a depressive-like syndrome. Concurrently, mice received either an omega-3 food supplement (FS) containing eicosapentaenoic acid (EPA; 0.55 mg/kg/day) and docosahexaenoic acid (DHA; 0.55 mg/kg/day) or a vehicle. Post-stress, we evaluated anxiety- and depressive-like behaviors, blood corticosterone levels, brain expression of pro-inflammatory cytokines, and conducted metabolome analysis of brain, liver and blood plasma.

Results

US-exposed mice treated with vehicle exhibited decreased sucrose preference, a sign of anhedonia, a key feature of depression, increased anxiety-like behavior, elevated corticosterone levels, and enhanced TNF and IL-1β gene expression in the brain. In contrast, US-FS mice did not display these changes. Omega-3 supplementation also reduced anxiety-like behavior in non-stressed mice. Metabolomic analysis revealed US-induced changes in brain energy metabolism, with FS increasing brain sphingomyelin. Liver metabolism was affected by both US and FS, while plasma metabolome changes were exclusive to FS. Brain glucose levels correlated positively with activity in anxiety tests.

Conclusion

Chronic omega-3 intake counteracted depressive- and anxiety-like behaviors in a US model of juvenile depression in mice. These effects likely stem from the anti-inflammatory properties of the supplement, suggesting potential therapeutic applications in juvenile depression.

BDNF and its Role in the Alcohol Abuse Initiated During Early Adolescence: Evidence from Preclinical and Clinical Studies

Brain-derived neurotrophic factor (BDNF) is a crucial brain signaling protein that is integral to many signaling pathways. This neurotrophin has shown to be highly involved in brain plastic processes such as neurogenesis, synaptic plasticity, axonal growth, and neurotransmission, among others. In the first part of this review, we revise the role of BDNF in different neuroplastic processes within the central nervous system. On the other hand, its deficiency in key neural circuits is associated with the development of psychiatric disorders, including alcohol abuse disorder. Many people begin to drink alcohol during adolescence, and it seems that changes in BDNF are evident after the adolescent regularly consumes alcohol. Therefore, the second part of this manuscript addresses the involvement of BDNF during adolescent brain maturation and how this process can be negatively affected by alcohol abuse. Finally, we propose different BNDF enhancers, both behavioral and pharmacological, which should be considered in the treatment of problematic alcohol consumption initiated during the adolescence.

Suicidal behavior and associated factors among prisoners at Dessie town correctional institution, Dessie, Ethiopia

BACKGROUND

Suicide is a prominent cause of death among inmates worldwide, accounting for over 30% of all deaths. Several factors, including prison-related, psychiatric disorders, stressful life events, and substance use-related factors are believed to be associated with an increased risk of suicidal behavior in a correctional facility. The present study aimed to determine the prevalence and associated factors of Suicidal Behavior among prisoners at Dessie town correctional institution, Ethiopia.

METHODS

From February 16 to March 5, 2020, a cross-sectional survey was conducted among 288 inmates at the Dessie Town Correctional Center. A systematic random sampling technique was used to select study participants during the study period. Data was collected through face-to-face interview methods using Suicidal Behavior Revised (SBQ-R). The collected data were coded, entered into Epi-data data version 3.1, and analyzed by SPSS Version 26. Binary logistic regression was carried out to identify independent predictors of suicidal behavior at a 95% confidence level. Variables at a p-value < 0.05 with 95% CI were declared statistically significant.

RESULTS

The prevalence of Suicidal behavior among prisoners was found to be 25.3% [(95% CI: 20.5, 30.6)]. This study showed that being female [AOR = 5.14;95% CI (1.62,16.29)], depression [AOR = 4.97;95%CI (2.53,9.77)], anxiety [AOR = 3.14; 95%CI (1.59,6.22)], experienced stressful life events [AOR = 5.11; 95%CI (2.24, 11.65)], and ever substance use [AOR = 2.83; 95%CI (1.41, 5.59)] were variables significantly associated with suicidal behavior among prisoners in Dessie town correctional institution.

CONCLUSION AND RECOMMENDATIONS

In this study, suicidal behavior was highly prevalent among prisoners compared to the general population. Being female, depression, anxiety, stress full life events, and substance use were variables that are independent predictors of suicidal behavior. This study recommends that the institution needs to deliver an appropriate psychiatric facility to diagnose and treat prisoners with suicidal behavior. Also, special attention should be given to early screening and treatment of prisoners through prison health services, which is the most critical prevention strategy of suicide in prisoners.

Exploring the association between depression, suicidality and serum neurotrophin levels in adolescents

Objective: The aim of this study was to identify potential differences in serum brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF), nerve growth factor (NGF) and neurotrophin-3 (NTF3) levels in adolescents with major depressive disorder (MDD) compared to healthy controls. The possible relationship between serum neurotrophin levels and suicidality in adolescents with MDD was also addressed.Methods: A total of 70 treatment-free adolescents with MDD and 40 healthy controls aged 11 to 19 years were enrolled. The severity of suicidality was determined using the Columbia-Suicide Severity Rating Scale, and the severity of depression and anxiety symptoms were evaluated by self-report inventories. Serum levels of neurotrophins were measured using an enzyme-linked immunosorbent assay.Results: The mean serum BDNF levels were significantly higher in adolescents with MDD than in control subjects; no significant difference was found between the groups for serum GDNF, NGF and NTF3 levels. No correlations were found between the levels of serum neurotrophins and the severity of depression or suicidality.Conclusions: The study results suggest that elevated serum BDNF levels may be related to MDD in adolescents. However, our findings did not support a role for neurotrophins in suicidality.Key pointsSerum BDNF levels were higher in adolescents with MDD than in controls.No significant alterations of serum levels of GDNF, NGF and NTF3 were evident in adolescents with MDD.Neurotrophin levels were not associated with suicidal ideation and behaviours.

Serum brain-derived neurotrophic factor levels in subjects with major depressive disorder with previous suicide attempt: A population-based study

Major depressive disorders (MDD) and suicide are significant public health concerns. Recent studies have been demonstrated that alterations in Brain Derived Neurotrophic Factor (BDNF) can be associated with this psychiatric disorders, MDD and suicide. Thus, the aim of this study was to evaluate differences in serum levels in individuals with MDD and with or without suicide attempt (SA), from a population-based sample. This was a paired cross-sectional study nested in a population-based study. The psychopathology screen was performed with the Mini-International Neuropsychiatric Interview (MINI). The total population of the sample consisted of 147 subjects distributed in three groups: 49 healthy controls, 49 subjects with MDD and 49 subjects with MDD and SA (MDD + SA). The BDNF serum levels were significantly reduced in subjects with MDD and MDD + SA compared to the healthy controls. However, there were no significant differences between the MDD and MDD + SA groups with respect to BDNF serum levels. These results suggest that SA did not interfere in the serum levels of BDNF, indicating that this neurotrophin may be related to the diagnosis of MDD and not to suicide attempt.

Epigenetic Dysregulation in the Prefrontal Cortex of Suicide Completers

The epigenome is thought to mediate between genes and the environment, particularly in response to adverse life experiences. Similar to other psychiatric diseases, the suicide liability of an individual appears to be influenced by many genetic factors of small effect size as well as by environmental stressors. To identify epigenetic marks associated with suicide, which is considered the endpoint of complex gene-environment interactions, we compared the cortex DNA methylation patterns of 6 suicide completers versus 6 non-psychiatric sudden-death controls, using Illumina 450K methylation arrays. Consistent with a multifactorial disease model, we found DNA methylation changes in a large number of genes, but no changes with large effects reaching genome-wide significance. Global methylation of all analyzed CpG sites was significantly (0.25 percentage point) lower in suicide than in control brains, whereas the vast majority (97%) of the top 1,000 differentially methylated regions (DMRs) were higher methylated (0.6 percentage point) in suicide brains. Annotation analysis of the top 1,000 DMRs revealed an enrichment of differentially methylated promoters in functional categories associated with transcription and expression in the brain. In addition, we performed a comprehensive literature research to identify suicide genes that have been replicated in independent genetic association, brain methylation and/or expression studies. Although, in general, there was no significant overlap between different published data sets or between our top 1,000 DMRs and published data sets, our methylation screen strengthens a number of candidate genes (APLP2, BDNF, HTR1A, NUAK1, PHACTR3, MSMP, SLC6A4, SYN2, and SYNE2) and supports a role for epigenetics in the pathophysiology of suicide.

Addiction science: Uncovering neurobiological complexity

Until very recently addiction-research was limited by existing tools and strategies that were inadequate for studying the inherent complexity at each of the different phenomenological levels. However, powerful new tools (e.g., optogenetics and designer drug receptors) and high throughput protocols are starting to give researchers the potential to systematically interrogate "all" genes, epigenetic marks, and neuronal circuits. These advances, combined with imaging technologies (both for preclinical and clinical studies) and a paradigm shift toward open access have spurred an unlimited growth of datasets transforming the way we investigate the neurobiology of substance use disorders (SUD) and the factors that modulate risk and resilience. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.