Prognostic effect of serum BDNF levels in late-life depression: Moderated by childhood trauma and SSRI usage?

Sex-controlled differences in sertraline and citalopram efficacies in major depressive disorder: a randomized, double-blind trial

To investigate the response to antidepressants while controlling for sex, which has been controversial, 92 outpatient males and females with major depressive disorder were assigned to sertraline (100 mg/day) or citalopram (40 mg/day) in two strata and were assessed using Hamilton depression rating scale (HDRS) scores and brain-derived neurotrophic factor (BDNF), interleukin (IL)-6 and cortisol serum levels in this 8-week, randomized, parallel-group, double-blind clinical trial. Data of 40 sertraline and 40 citalopram recipients with equal representation of males and females assigned to each medication were analyzed, while their baseline characteristics were not statistically different (P > 0.05). There were no significant differences between sertraline and citalopram recipients in outcome changes (P > 0.05), all of which indicated improvement, but a significant time-treatment-sex interaction effect in BDNF levels was observed (P = 0.035). Regarding this, subgroup analyses illustrated a significantly greater increase in male BDNF levels following sertraline treatment (P = 0.020) with a moderate to large effect size (Cohen's d = 0.76 and ). Significant associations were observed between percentage changes in IL-6 levels and BDNF levels in sertraline recipients (P = 0.033) and HDRS scores in citalopram recipients (P < 0.001). Sex was an effect modifier in BDNF alterations following sertraline and citalopram administration. Further large-scale, high-quality, long-term studies are recommended.

Relationship between BDNF and oxytocin

Converging, albeit scattered data mainly gathered in animals indicate that the neurotrophin brain-derived neurotrophic factor (BDNF) and the nonapeptide oxytocin (OT) interact in a cooperative way. Data in humans are really limited and indirect. Therefore, the aim of the present study was to explore the possible existence of a link between OT and BDNF in humans, by means of two peripheral markers, the platelet-poor-plasmatic-BDNF (PPP-BDNF) and the platelet BDNF (PLT-BDNF) and OT levels. Twenty-six young healthy controls of both sexes who volunteered for the study were included in the study. Fifty ml of peripheral venous blood were drawn from one-night fasting subjects between 8.00 and 9.00 a.m. The BDNF and OT assays were carried out according to common methods. Comparisons for continuous variables were performed by the Student's t-test for variables that follow a normal distribution, and by the Wilcoxon-Mann-Whitney test for variables not normally distributed. The correlations between biological markers were explored by calculating the Pearson's correlation coefficient or Spearman's rank correlation. The results showed that PLT-BDNF (pg/mg proteins, mean ± SD) and PPP-BDNF (pg/ml, mean ± SD) were 1546 ± 1844 and 10111 ± 1892, respectively. The OT levels (pg/ml, mean ± SD) were 13.92 ± 4.54. The OT levels were significantly higher in women than in men. The Spearman's analysis revealed a statistically significant and negative correlation between OT levels and PLT-BDNF (R = -0.543, p = 0.004). The findings of this study highlight the presence of a significant and negative correlation between OT and PLT-BDNF in a small group of healthy controls of both sexes. In any case, despite all the limits of peripheral biomarkers, they suggest that this reciprocal influence might have a downstream homeostatic function dampening one activity when the other is activated or no longer necessary, maybe at the level of the stress and/or immune systems.

Brain-Derived Neurotrophic Factor (BDNF) as a Predictor of Treatment Response in Major Depressive Disorder (MDD): A Systematic Review

Brain-derived neurotrophic factor (BDNF) has been studied as a biomarker of major depressive disorder (MDD). Besides diagnostic biomarkers, clinically useful biomarkers can inform response to treatment. We aimed to review all studies that sought to relate BDNF baseline levels, or BDNF polymorphisms, with response to treatment in MDD. In order to achieve this, we performed a systematic review of studies that explored the relation of BDNF with both pharmacological and non-pharmacological treatment. Finally, we reviewed the evidence that relates peripheral levels of BDNF and BDNF polymorphisms with the development and management of treatment-resistant depression.

Late-life depression: Epidemiology, phenotype, pathogenesis and treatment before and during the COVID-19 pandemic

Late-life depression (LLD) is one of the most common mental disorders among the older adults. Population aging, social stress, and the COVID-19 pandemic have significantly affected the emotional health of older adults, resulting in a worldwide prevalence of LLD. The clinical phenotypes between LLD and adult depression differ in terms of symptoms, comorbid physical diseases, and coexisting cognitive impairments. Many pathological factors such as the imbalance of neurotransmitters, a decrease in neurotrophic factors, an increase in β-amyloid production, dysregulation of the hypothalamic-pituitary-adrenal axis, and changes in the gut microbiota, are allegedly associated with the onset of LLD. However, the exact pathogenic mechanism underlying LLD remains unclear. Traditional selective serotonin reuptake inhibitor therapy results in poor responsiveness and side effects during LLD treatment. Neuromodulation therapies and complementary and integrative therapies have been proven safe and effective for the treatment of LLD. Importantly, during the COVID-19 pandemic, modern digital health intervention technologies, including socially assistive robots and app-based interventions, have proven to be advantageous in providing personal services to patients with LLD.

Neurotrophic factors, childhood trauma and psychiatric disorders: A systematic review of genetic, biochemical, cognitive and imaging studies to identify potential biomarkers

BACKGROUND

Exposure to traumatic experience represents one of the key environmental factors influencing the risk for several psychiatric disorders, in particular when suffered during childhood, a critical period for brain development, characterized by a high level of neuroplasticity. Abnormalities affecting neurotrophic factors might play a fundamental role in the link between childhood trauma (CT) and early life stress (ELS) and psychiatric disorders.

METHODS

A systematic review was conducted, considering genetic, biochemical and expression studies along with cognitive and brain structure imaging investigations, based on PubMed and Web of Science databases (available up until November 2021), to identify potential neuroplasticity related biomarkers associated both with CT/ELS and psychiatric disorders. The search was followed by data abstraction and study quality assessment (Newcastle-Ottawa Scale).

RESULTS

103 studies met our eligibility criteria. Among them, 65 were available for genetic, 30 for biochemical and 3 for mRNA data; 45 findings were linked to specific symptomatology/pathologies, 16 with various cognitive functions, 19 with different brain areas, 6 on methylation and 36 performed on control subjects for the Brain Derived Neurotrophic Factor (BDNF); whereas 4 expression/biochemical studies covered Neurotrophin 4 (NT-4), Vascular Endothelium Growth Factor (VEGF), Epidermal Growth Factor (EGF), Fibroblast Growth Factor (FGF), and Transforming Growth Factor β1 (TGF-β1).

LIMITATIONS

Heterogeneity of assessments (biological, psychological, of symptomatology, and CT/ELS), age range and ethnicity of samples for BDNF studies; limited studies for other neurotrophins.

CONCLUSIONS

Results support the key role of BDNF (in form of Met allele) as biomarker, both at genetic and biochemical level, in mediating the effect of CT/ELS in psychiatric disorders, passing through specific cognitive functions and specific brain region architecture.

Intermediation of perceived stress between early trauma and plasma M/P ratio levels in obsessive-compulsive disorder patients

OBJECTIVES

This study is to find the correlation among BDNF metabolism, early trauma, and current stress status of OCD patients. As well as to study the BDNF metabolism-stress related pathological mechanism in OCD development.

METHODS

A total of 140 participants were recruited in this study, including 64 drug-naïve OCD patients (OCDs) and 76 healthy controls (HCs). The clinical data of the subjects were measured using YBOCS, CTQ, and PSS. The plasma mBDNF and proBDNF values were measured by ELISA while the M/P ratio was calculated.

RESULTS

The mBDNF, proBDNF plasma levels, and M/P ratio of unmedicated OCD individuals decreased evidently comparing with HCs. Also, positive associations were found between PSS and CTQ and between CTQ and M/P ratio. The negative correlation included proBDNF and PSS as well as proBDNF and CTQ. Intermediary analysis generated by SPSS has showed that the perceived stress played a complete mediating role between early trauma and plasma M/P ratio levels, and the mediating effect was 0.043 in non-medication OCD patients.

CONCLUSIONS

Findings from this study suggested that early trauma experience and stress state work together in regulating BDNF metabolism level in OCD patients. The nucleus accumbens and reward loop are also pivotal in the pathogenesis of OCD.

Blood Brain-Derived Neurotrophic Factor (BDNF) and Major Depression: Do We Have a Translational Perspective?

Major depressive disorder (MDD) affects millions of people worldwide and is a leading cause of disability. Several theories have been proposed to explain its pathological mechanisms, and the “neurotrophin hypothesis of depression” involves one of the most relevant pathways. Brain-derived neurotrophic factor (BDNF) is an important neurotrophin, and it has been extensively investigated in both experimental models and clinical studies of MDD. Robust empirical findings have indicated an association between increased BDNF gene expression and peripheral concentration with improved neuronal plasticity and neurogenesis. Additionally, several studies have indicated the blunt expression of BDNF in carriers of the Val66Met gene polymorphism and lower blood BDNF (serum or plasma) levels in depressed individuals. Clinical trials have yielded mixed results with different treatment options, peripheral blood BDNF measurement techniques, and time of observation. Previous meta-analyses of MDD treatment have indicated that antidepressants and electroconvulsive therapy showed higher levels of blood BDNF after treatment but not with physical exercise, psychotherapy, or direct current stimulation. Moreover, the rapid-acting antidepressant ketamine has presented an early increase in blood BDNF concentration. Although evidence has pointed to increased levels of BDNF after antidepressant therapy, several factors, such as heterogeneous results, low sample size, publication bias, and different BDNF measurements (serum or plasma), pose a challenge in the interpretation of the relation between peripheral blood BDNF and MDD. These potential gaps in the literature have not been properly addressed in previous narrative reviews. In this review, current evidence regarding BDNF function, genetics and epigenetics, expression, and results from clinical trials is summarized, putting the literature into a translational perspective on MDD. In general, blood BDNF cannot be recommended for use as a biomarker in clinical practice. Moreover, future studies should expand the evidence with larger samples, use the serum or serum: whole blood concentration of BDNF as a more accurate measure of peripheral BDNF, and compare its change upon different treatment modalities of MDD.

State-of-the-Art: Inflammatory and Metabolic Markers in Mood Disorders

Mounting evidence highlights the involvement of inflammatory/immune systems and their relationships with neurotransmitters and different metabolic processes in mood disorders. Nevertheless, there is a general agreement that available findings are still inconclusive. Therefore, further investigations are required, aimed at deepening the role of possible alterations of biomarkers in the pathophysiology of mood disorders that might lead to more focused and tailored treatments. The present study is a comprehensive review on these topics that seem to represent intriguing avenues for the development of real innovative therapeutic strategies of mood disorders.