Correlation between serum brain-derived neurotrophic factor level and an in vivo marker of cortical integrity

The Possible Role of Brain-derived Neurotrophic Factor in Epilepsy

Epilepsy is a neurological disease characterized by repeated seizures. Despite of that the brain-derived neurotrophic factor (BDNF) is implicated in the pathogenesis of epileptogenesis and epilepsy, BDNF may have a neuroprotective effect against epilepsy. Thus, the goal of the present review was to highlight the protective and detrimental roles of BDNF in epilepsy. In this review, we also try to find the relation of BDNF with other signaling pathways and cellular processes including autophagy, mTOR pathway, progranulin (PGN), and α-Synuclein (α-Syn) which negatively and positively regulate BDNF/tyrosine kinase receptor B (TrkB) signaling pathway. Therefore, the assessment of BDNF levels in epilepsy should be related to other neuronal signaling pathways and types of epilepsy in both preclinical and clinical studies. In conclusion, there is a strong controversy concerning the potential role of BDNF in epilepsy. Therefore, preclinical, molecular, and clinical studies are warranted in this regard.

Biomarkers and Tourette syndrome: a systematic review and meta-analysis

Objective

This research aims to investigate whether peripheral biomarkers might differentiate individuals with Tourette syndrome (TS) from those without the condition.

Methods

A broad range of databases was searched through November 2022. This study employed a systematic literature review and subsequent meta-analysis of case-control studies that assessed the aberration of biomarkers of patients with TS and controls.

Results

A total of 81 studies were identified, out of which 60 met the eligibility criteria for inclusion in the meta-analysis. Following a meticulous screening procedure to determine the feasibility of incorporating case-control studies into the meta-analysis, 13 comparisons were statistically significant [CD3+ T cell, CD4+ T cell, CD4+ T cell to CD8+ T cell ratio, NK-cell, anti-streptolysin O antibodies, anti-DNase antibodies, glutamic acid (Glu), aspartic acid (Asp), ferritin (Fe), zinc (Zn), lead (Pb), vitamin D, and brain-derived neurotrophic factor (BDNF)]. Publication bias was found for anti-streptolysin O antibodies. Suggestive associations were evidenced for norsalsolinol (NSAL), neuron-specific enolase (NSE), and S100B.

Conclusion

In this study, we present empirical evidence substantiating the link between several peripheral biomarkers and the early diagnosis of TS. Larger and more standardized studies are necessary to replicate the observed results, elucidate the specificity of the biomarkers for TS, and evaluate their precision for use in clinical settings.

The role of BDNF in major depressive disorder, related clinical features, and antidepressant treatment: insight from meta-analyses

The brain-derived neurotrophic factor (BDNF) has received considerable attention as a potential biomarker of major depressive disorder (MDD) and antidepressant response. We conducted an overview of meta-analyses investigating the relationship of BDNF with MDD, related clinical features, and antidepressant treatment. Based on a systematic screening on main electronic databases, 11 systematic reviews with meta-analyses were included. Available evidence suggests that people with MDD have peripheral and central BDNF levels lower than non-depressed individuals. A negative correlation between blood BDNF and symptom severity emerged, while no association with suicidality was detected. Moreover, an increase in blood BDNF levels after antidepressant treatment, proportional to symptom improvement, was reported. BDNF levels seem to be increased in both treatment responders and remitters, remaining stable in non-responders. Conversely, no variations of BDNF concentrations after non-pharmacological interventions (electroconvulsive therapy, repetitive transcranial magnetic stimulation, and physical activity) were found. The findings of this overview appear consistent with the neurotrophic hypothesis of depression, suggesting that BDNF may play a role in both MDD pathophysiology and pharmacological treatment response.

Oxidative Stress Biomarkers among Schizophrenia Inpatients

Background. Finding the associations between schizophrenia symptoms and the biomarkers of inflammation, oxidative stress and the kynurenine pathway may lead to the individualization of treatment and increase its effectiveness. Methods. The study group included 82 schizophrenia inpatients. The Positive and Negative Symptoms Scale (PANSS), the Brief Assessment of Cognition in Schizophrenia (BACS) and the Calgary Depression in Schizophrenia Scale were used for symptom evaluation. Biochemical analyses included oxidative stress parameters and brain-derived neurotrophic factor (BDNF). Results. Linear models revealed the following: (1) malondiadehyde (MDA), N-formylkynurenine (N-formKYN), advanced oxidation protein products (AOPP), advanced glycation end-products of proteins (AGE) and total oxidative status (TOS) levels are related to the PANSS-total score; (2) MDA, reduced glutathione (GSH) and BDNF levels are related to the PANSS-negative score; (3) TOS and kynurenine (KYN) levels are related to the PANSS-positive score; (4) levels of total antioxidant status (TAS) and AOPP along with the CDSS score are related to the BACS-total score; (5) TAS and N-formKYN levels are related to the BACS-working memory score. Conclusions. Oxidative stress biomarkers may be associated with the severity of schizophrenia symptoms in positive, negative and cognitive dimensions. The identification of biochemical markers associated with the specific symptom clusters may increase the understanding of biochemical profiles in schizophrenia patients.

BDNF as a biomarker for neuropathic pain: Consideration of mechanisms of action and associated measurement challenges

INTRODUCTION

The primary objective of this paper is to (1) provide a summary of human studies that have used brain derived neurotrophic factor (BDNF) as a biomarker, (2) review animal studies that help to elucidate the mechanistic involvement of BDNF in the development and maintenance of neuropathic pain (NP), and (3) provide a critique of the existing measurement techniques to highlight the limitations of the methods utilized to quantify BDNF in different biofluids in the blood (i.e., serum and plasma) with the intention of presenting a case for the most reliable and valid technique. Lastly, this review also explores potential moderators that can influence the measurement of BDNF and provides recommendations to standardize its quantification to reduce the inconsistencies across studies.

METHODS

In this manuscript we examined the literature on BDNF, focusing on its role as a biomarker, its mechanism of action in NP, and critically analyzed its measurement in serum and plasma to identify factors that contribute to the discrepancy in results between plasma and serum BDNF values.

RESULTS

A large heterogenous literature was reviewed that detailed BDNF's utility as a potential biomarker in healthy volunteers, patients with chronic pain, and patients with neuropsychiatric disorders but demonstrated inconsistent findings. The literature provides insight into the mechanism of action of BDNF at different levels of the central nervous system using animal studies. We identified multiple factors that influence the measurement of BDNF in serum and plasma and based on current evidence, we recommend assessing serum BDNF levels to quantify peripheral BDNF as they are more stable and sensitive to changes than plasma BDNF.

CONCLUSION

Although mechanistic studies clearly explain the role of BDNF, results from human studies are inconsistent. More studies are needed to evaluate the methodological challenges in using serum BDNF as a biomarker in NP.

Development and validation of brain-derived neurotrophic factor measurement in human urine samples as a non-invasive effect biomarker

Background

Brain-derived neurotrophic factor (BDNF), a neurotrophic growth factor mainly expressed in the brain, has been proposed as a potential effect biomarker; that is, as a measurable biomarker whose values could be associated with several diseases, including neurological impairments. The European Human Biomonitoring Initiative (HBM4EU) has also recognized effect biomarkers as a useful tool for establishing link between exposure to environmental pollutants and human health. Despite the well-establish protocol for measuring serum BDNF, there is a need to validate its assessment in urine, a non-invasive sample that can be easily repeated over time. The aim of this study was to develop, standardize and validate a methodology to quantify BDNF protein levels in urine samples before its implementation in biomonitoring studies.

Methods

Different experimental conditions and non-competitive commercial enzyme-linked immunosorbent assay (ELISA) kits were tested to determine the optimal analytical procedure, trying to minimize the shortcomings of ELISA kits. The fine-tune protocol was validated in a pilot study using both upon awakening (n = 150) and prior to sleeping (n = 106) urine samples from the same Spanish adolescent males in a well-characterized study population (the Spanish INMA-Granada cohort).

Results

The best results were obtained in 0.6 ml of urine after the acidification and extraction (pre-concentration) of samples. The highest reproducibility was obtained with the ELISA kit from Raybiotech. Urinary BDNF concentrations of adolescent males were within the previously reported range (morning = 0.047-6.801 ng/ml and night = 0.047-7.404 ng/ml). Urinary BDNF levels in the awakening and pre-sleep samples did not follow a normal distribution and were not correlated.

Conclusion

The developed methodology offers good sensitivity and reproducibility. Having reliable markers in urine may facilitate both diagnosis and monitoring possible diseases (and treatment). Further studies are needed to implement urinary BDNF in biomonitoring studies to further elucidate its usefulness and biological significance for neurological impairments.

Peripheral brain-derived neurotrophic factor (BDNF) and salivary cortisol levels in college students with different levels of academic stress. Study protocol

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) is essential for brain physiological processes influencing memory and learning. BDNF levels can be affected by many factors, including stress. Stress increase serum and salivary cortisol levels. Academic stress is of the chronic type. BDNF levels can be measure from serum, plasma or platelets, and there is still no standard methodology, which is relevant to ensure reproducibility and comparability between studies.

HYPOTHESIS

(i) BDNF concentrations in serum show greater variability than in plasma. (ii) In college students with academic stress, peripheral BDNF decreases and salivary cortisol increases.

GENERAL OBJECTIVE

To standardize plasma and serum collection for BDNF levels and to determine whether academic stress affects peripheral BDNF and salivary cortisol levels.

DESIGN

Quantitative research, with a non-experimental cross-sectional descriptive design.

PARTICIPANTS

Student volunteers. Under convenience sampling, 20 individuals will be included for standardization of plasma and serum collection and between 70 and 80 individuals to determine the effect of academic stress on BDNF and salivary cortisol.

PERIPHERAL BLOOD AND SALIVARY CORTISOL SAMPLING, MEASUREMENTS

12 mL of peripheral blood (with and without anticoagulant) will be drawn per participant, separated from plasma or serum and cryopreserved at -80°C. Additionally, they will be instructed in the collection of 1 mL of saliva samples, which will be centrifuged. Val66Met polymorphism will be performed by allele-specific PCR, while BDNF and salivary cortisol levels will be determined by ELISA.

STATISTICAL ANALYSIS

(i) descriptive analysis of the variables, through measures of central tendency and dispersion, and the categorical variables through their frequency and percentage. (ii) Then a bivariate analysis will be performed comparing groups using each variable separately.

EXPECTED RESULTS

We expect to (i) determine the analytical factors that allow a better reproducibility in the measurement of peripheral BDNF, and (ii) the effect of academic stress on BDNF and salivary cortisol levels.

Vitamin D deficit is associated with accelerated brain aging in the general population

Vitamin D deficiency has been associated with reduced neurocognitive functioning and the neurodegenerative processes. However, existing evidence on brain structural correlates of vitamin D deficiency is controversial. We sought to investigate associations of vitamin D levels with imaging patterns of brain aging. In addition, we investigated whether low vitamin D levels were associated with gray matter volumes, whole brain volumes and hippocampus volumes. Structural MRI data and vitamin D levels were obtained in 1,865 subjects from the general population. Linear regressions were applied to investigate the association of vitamin D levels and vitamin D deficiency with imaging derived brain age, total brain, gray matter and hippocampal volumes. Different sets of covariates were included. Vitamin D deficiency was significantly associated with increased brain age. Also, linear vitamin D levels were significantly associated with total brain and gray matter volumes, while no significant association with hippocampal volume was found. Further interaction analyses showed that this association was only significant for male subjects. Our results support previous findings suggesting that vitamin D-deficient individuals have an accelerated brain aging. In addition, associations between vitamin D levels and total brain/ gray matter volumes suggest neuroprotective effects of vitamin D on the brain.

Is there a relationship between morphological and functional platelet changes and depressive disorder?

BACKGROUND

Blood platelets, due to shared biochemical and functional properties with presynaptic serotonergic neurons, constituted, over the years, an attractive peripheral biomarker of neuronal activity. Therefore, the literature strongly focused on the investigation of eventual structural and functional platelet abnormalities in neuropsychiatric disorders, particularly in depressive disorder. Given their impact in biological psychiatry, the goal of the present paper was to review and critically analyze studies exploring platelet activity, functionality, and morpho-structure in subjects with depressive disorder.

METHODS

According to the PRISMA guidelines, we performed a systematic review through the PubMed database up to March 2020 with the search terms: (1) platelets in depression [Title/Abstract]"; (2) "(platelets[Title]) AND depressive disorder[Title/Abstract]"; (3) "(Platelet[Title]) AND major depressive disorder[Title]"; (4) (platelets[Title]) AND depressed[Title]"; (5) (platelets[Title]) AND depressive episode[Title]"; (6) (platelets[Title]) AND major depression[Title]"; (7) platelet activation in depression[All fields]"; and (8) platelet reactivity in depression[All fields]."

RESULTS

After a detailed screening analysis and the application of specific selection criteria, we included in our review a total of 106 for qualitative synthesis. The studies were classified into various subparagraphs according to platelet characteristics analyzed: serotonergic system (5-HT2A receptors, SERT activity, and 5-HT content), adrenergic system, MAO activity, biomarkers of activation, responsivity, morphological changes, and other molecular pathways.

CONCLUSIONS

Despite the large amount of the literature examined, nonunivocal and, occasionally, conflicting results emerged. However, the findings on structural and metabolic alterations, modifications in the expression of specific proteins, changes in the aggregability, or in the responsivity to different pro-activating stimuli, may be suggestive of potential platelet dysfunctions in depressed subjects, which would result in a kind of hyperreactive state. This condition could potentially lead to an increased cardiovascular risk. In line with this hypothesis, we speculated that antidepressant treatments would seem to reduce this hyperreactivity while representing a potential tool for reducing cardiovascular risk in depressed patients and, maybe, in other neuropsychiatric conditions. However, the problem of the specificity of platelet biomarkers is still at issue and would deserve to be deepened in future studies.

A Meta-Analysis of Brain-Derived Neurotrophic Factor Effects on Brain Volume in Schizophrenia: Genotype and Serum Levels

AIM

The Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene has established pleiotropic effects on schizophrenia incidence and morphologic alterations in the illness. The effects of brain-derived neurotrophic factor (BDNF) on brain volume measurements are however mixed seeming to be less established for most brain regions. The current meta-analytic review examined (1) the association of the Val66Met SNP and brain volume alterations in schizophrenia by comparing Met allele carriers to Val/Val homozygotes and (2) the association of serum BDNF with brain volume measurements.

METHOD

Studies included in the meta-analyses were identified through an electronic search of PubMed and PsycInfo (via EBSCO) for English language publications from January 2000 through December 2017. Included studies had conducted a genotyping procedure of Val66Met or obtained assays of serum BDNF and obtained brain volume data in patients with psychotic disorders. Nonhuman studies were excluded.

RESULTS

Study 1 which included 52 comparisons of Met carriers and Val/Val homozygotes found evidence of lower right and left hippocampal volumes among Met allele carriers with schizophrenia. Frontal measurements, while also lower among Met carriers, did not achieve statistical significance. Study 2 which included 7 examinations of the correlation between serum BDNF and brain volume found significant associations between serum BDNF levels and right and left hippocampal volume with lower BDNF corresponding to lower volumes.

DISCUSSION

The meta-analyses provided evidence of associations between brain volume alterations in schizophrenia and variations on the Val66Met SNP and serum BDNF. Given the limited number of studies, it remains unclear if BDNF effects are global or regionally specific.

Moderate Exercise Combined with Enriched Environment Enhances Learning and Memory through BDNF/TrkB Signaling Pathway in Rats

This study aimed to investigate the effects and potential mechanisms of exercise combined with an enriched environment on learning and memory in rats. Forty healthy male Wistar rats (7 weeks old) were randomly assigned into 4 groups (N = 10 in each group): control (C) group, treadmill exercise (TE) group, enriched environment (EE) group and the TE + EE group. The Morris water maze (MWM) test was used to evaluate the learning and memory ability in all rats after eight weeks of exposure in the different conditions. Moreover, we employed enzyme-linked immunosorbent assay (ELISA) to determine the expression of brain-derived neurotrophic factor (BDNF) and receptor tyrosine kinase B (TrkB) in the rats. The data showed that the escape latency and the number of platform crossings were significantly better in the TE + EE group compared to the TE, EE or C groups (p < 0.05). In addition, there was upregulation of BDNF and TrkB in rats in the TE + EE group compared to those in the TE, EE or C groups (p < 0.05). Taken together, the data robustly demonstrate that the combination of TE + EE enhances learning and memory ability and upregulates the expression of both BDNF and TrkB in rats. Thus, the BDNF/TrkB signaling pathway might be modulating the effect of exercise and enriched environment in improving learning and memory ability in rats.

Association between hippocampal structure and serum Brain-Derived Neurotrophic Factor (BDNF) in healthy adults: A registered report

The hippocampus is a highly plastic brain structure supporting functions central to human cognition. Morphological changes in the hippocampus have been implicated in development, aging, as well as in a broad range of neurological and psychiatric disorders. A growing body of research suggests that hippocampal plasticity is closely linked to the actions of brain-derived neurotrophic factor (BDNF). However, evidence on the relationship between hippocampal volume (HCV) and peripheral BDNF levels is scarce and limited to elderly and patient populations. Further, despite evidence that BDNF expression differs throughout the hippocampus and is implicated in adult neurogenesis specifically in the dentate gyrus, no study has so far related peripheral BDNF levels to the volumes of individual hippocampal subfields. Besides its clinical implications, BDNF-facilitated hippocampal plasticity plays an important role in regulating cognitive and affective processes. In the current registered report, we investigated how serum BDNF (sBDNF) levels relate to volumes of the hippocampal formation and its subfields in a large sample of healthy adults (N = 279, 160 f) with a broad age range (20-55 years, mean 40.5) recruited in the context of the ReSource Project. We related HCV to basal sBDNF and, in a subsample (n = 103, 57 f), to acute stress-reactive change in sBDNF. We further tested the role of age as a moderator of both associations. Contrary to our hypotheses, neither basal sBDNF levels nor stress-reactive sBDNF change were associated with total HCV or volume of the dentate gyrus/cornu ammonis 4 (DG/CA4) subfield. We also found no evidence for a moderating effect of age on any of these associations. Our null results provide a first point of reference on the relationship between sBDNF and HCV in healthy mid-age, in contrast to patient or aging populations. We suggest that sBDNF levels have limited predictive value for morphological differences of the hippocampal structure when notable challenge to its neuronal integrity or to neurotrophic capacity is absent.

Nerve impulse transmission pathway-focused genes expression analysis in patients with primary hypothyroidism and autoimmune thyroiditis

OBJECTIVE

Thyroid hormones have important actions in the adult brain. They regulate genes expression in myelination, differentiation of neuronal and glial cells, and neuronal viability and function.

METHODS

We used the pathway-specific real-time PCR array (Neurotrophins and Receptors RT2 Profiler PCR Array, QIAGEN, Germany) to identify and verify nerve impulse transmission pathway-focused genes expression in peripheral white blood cells of patients with postoperative hypothyroidism, hypothyroidism as a result of autoimmune thyroiditis (AIT) and AIT with elevated serum an anti-thyroglobulin (anti-Tg) and anti-thyroid peroxidase (anti-TPO) antibodies.

RESULTS

It was shown that patients with postoperative hypothyroidism and hypothyroidism resulting from AIT had significantly lower expression of BDNF and CBLN1. In patients with AIT with elevated serum anti-Tg and anti-TPO antibodies, the expression of GDNF was significantly down-regulated and the expression of PNOC was up-regulated. The expression levels of MEF2C and NTSR1 were decreased in the group of patients with postoperative hypothyroidism and AIT, correspondingly.

CONCLUSIONS

The results of this study demonstrate that AIT and hypothyroidism can affect the expression of mRNA nerve impulse transmission genes in gene specific manner and that these changes in gene expressions can be playing a role in the development of neurological complications associated with thyroid pathology. Detection of the transcriptional activity of nerve impulse transmission genes in peripheral white blood cells can be used as an important minimally invasive prognostic marker of the risk for developing neurological complications comorbid with thyroid pathology.

Concepts of Neuroinflammation and Their Relationship With Impaired Mitochondrial Functions in Bipolar Disorder

Bipolar disorder (BD) is a chronic psychiatric disease, characterized by frequent behavioral episodes of depression and mania, and neurologically by dysregulated neurotransmission, neuroplasticity, growth factor signaling, and metabolism, as well as oxidative stress, and neuronal apoptosis, contributing to chronic neuroinflammation. These abnormalities result from complex interactions between multiple susceptibility genes and environmental factors such as stress. The neurocellular abnormalities of BD can result in gross morphological changes, such as reduced prefrontal and hippocampal volume, and circuit reorganization resulting in cognitive and emotional deficits. The term "neuroprogression" is used to denote the progressive changes from early to late stages, as BD severity and loss of treatment response correlate with the number of past episodes. In addition to circuit and cellular abnormalities, BD is associated with dysfunctional mitochondria, leading to severe metabolic disruption in high energy-demanding neurons and glia. Indeed, mitochondrial dysfunction involving electron transport chain (ETC) disruption is considered the primary cause of chronic oxidative stress in BD. The ensuing damage to membrane lipids, proteins, and DNA further perpetuates oxidative stress and neuroinflammation, creating a perpetuating pathogenic cycle. A deeper understanding of BD pathophysiology and identification of associated biomarkers of neuroinflammation are needed to facilitate early diagnosis and treatment of this debilitating disorder.

AdipoRon Treatment Induces a Dose-Dependent Response in Adult Hippocampal Neurogenesis

AdipoRon, an adiponectin receptor agonist, elicits similar antidiabetic, anti-atherogenic, and anti-inflammatory effects on mouse models as adiponectin does. Since AdipoRon can cross the blood-brain barrier, its chronic effects on regulating hippocampal function are yet to be examined. This study investigated whether AdipoRon treatment promotes hippocampal neurogenesis and spatial recognition memory in a dose-dependent manner. Adolescent male C57BL/6J mice received continuous treatment of either 20 mg/kg (low dose) or 50 mg/kg (high dose) AdipoRon or vehicle intraperitoneally for 14 days, followed by the open field test to examine anxiety and locomotor activity, and the Y maze test to examine hippocampal-dependent spatial recognition memory. Immunopositive cell markers of neural progenitor cells, immature neurons, and newborn cells in the hippocampal dentate gyrus were quantified. Immunosorbent assays were used to measure the serum levels of factors that can regulate hippocampal neurogenesis, including adiponectin, brain-derived neurotrophic factor (BDNF), and corticosterone. Our results showed that 20 mg/kg AdipoRon treatment significantly promoted hippocampal cell proliferation and increased serum levels of adiponectin and BDNF, though there were no effects on spatial recognition memory and locomotor activity. On the contrary, 50 mg/kg AdipoRon treatment impaired spatial recognition memory, suppressed cell proliferation, neuronal differentiation, and cell survival associated with reduced serum levels of BDNF and adiponectin. The results suggest that a low-dose AdipoRon treatment promotes hippocampal cell proliferation, while a high-dose AdipoRon treatment is detrimental to the hippocampus function.

The improvement of cognitive deficits after whole-body cryotherapy - A randomised controlled trial

BACKGROUND

Whole-body cryotherapy (WBC) - a repetitive, short-term exposure to extremely low temperatures - may become an effective early intervention for mild cognitive impairment (MCI). It is a heterogeneous group of symptoms associated with cognitive dysfunction which is estimated to transform into dementia in 50% cases.

STUDY DESIGN

The prospective randomised double-blind sham-controlled study aimed to determine the efficacy of WBC on cognitive functioning and biological mechanisms. The study was registered with Australian New Zealand Clinical Trials Registry (ACTRN12619001627145).

METHODS

Participants with MCI (n = 62; (20<MoCA>26) were randomly allocated to cryogenic temperatures (-110 °C till -160 °C) (EG, n = 33) or placebo-controlled group (CG, n = 29). Cognitive functions were measured at baseline (T1), after the 10th WBC session (T2) and after 2 week-break (T3) with DemTect, SLUMS and Test Your Memory (TYM). Secondary outcome measures included quality of life (WHOQoL-BREF), self-reported well-being (VAS) and depressive symptoms (GDS). Whole blood samples (10 ml) were collected at T1 and T2 to evaluate levels of cytokines, neurotrophins, NO and biochemical parameters CRP total cholesterol, prolactin).

RESULTS

There were significant differences between groups measured at T2 in immediate recall (DemTect) and in orientation (TYM) in favour of WBC group. Improvement in mood was detected in self-reported depressive symptoms level (WHOQoL-26; T2 p = 0.04; VAS mood T2 p = 0.02; T3 p = 0.07). The significant reduction of BDNF level was observed (p < 0.05).

CONCLUSIONS

WBC may increase the performance of cognitive functions. It seems promising to combine WBC with existing behavioural and cognitive trainings in the future studies investigating early interventions methods in MCI.

Decreased Peripheral BDNF Levels and Cognitive Impairment in Late-Life Schizophrenia

Objectives: There are relatively few studies on mechanisms of cognitive deficits in late-life schizophrenia (LLS). Brain-derived neurotrophic factor (BDNF), as an important neuroplastic molecule, has been reported to be involved in neurocognitive impairment in schizophrenia. This study aimed to examine whether peripheral BDNF levels were associated with cognitive deficits in LLS, which has not been explored yet. Methods: Forty-eight LLS patients and 45 age-matched elderly controls were recruited. We measured all participants on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) for cognition and serum BDNF levels. Psychopathological symptoms in patients were assessed by the Positive and Negative Syndrome Scale (PANSS). Results: The levels of BDNF in LLS patients were significantly lower than those in healthy controls (8.80 ± 2.30 vs. 12.63 ± 5.08 ng/ml, p < 0.001). The cognitive performance of LLS patients was worse than that of the controls on RBANS total score and scores of immediate memory, attention, language, and delayed memory (all p ≤ 0.005). BDNF was positively associated with attention in LLS patients (r = 0.338, p = 0.019). Conclusion: Our findings suggest that older patients with schizophrenia exhibit lower BDNF levels and more cognitive deficits than older controls, supporting the accelerated aging hypothesis of schizophrenia. Moreover, decreased BDNF is related to attention deficits, indicating that BDNF might be a candidate biomarker of cognitive impairments in LLS patients.

Psychosocial Intervention for Youth With High Externalizing Behaviors and Aggression Is Associated With Improvement in Impulsivity and Brain Gray Matter Volume Changes

Background: Stop, Now And Plan (SNAP) is a cognitive behavioral-based psychosocial intervention that has a strong evidence base for treating youth with high aggression and externalizing behaviors, many of whom have disruptive behavior disorders. In a pre-post design, we tested whether SNAP could improve externalizing behaviors, assessed by the parent-rated Child Behavior Checklist (CBCL) and also improve behavioral measures of impulsivity in children with high aggression and impulsivity. We then investigated whether any improvement in externalizing behavior or impulsivity was associated with gray matter volume (GMV) changes assessed using structural magnetic resonance imaging (sMRI). We also recruited typically developing youth who were assessed twice without undergoing the SNAP intervention. Methods: Ten children who were participating in SNAP treatment completed the entire study protocol. CBCL measures, behavioral measures of impulsivity, and sMRI scanning was conducted pre-SNAP and then 13 weeks later post-SNAP. Twelve healthy controls also completed the study; they were rated on the CBCL, performed the same behavioral measure of impulsivity, and underwent sMRI twice, separated by 13 weeks. They did not receive the SNAP intervention. Result: At baseline, SNAP participants had higher CBCL scores and performed worse on the impulsivity task compared with the healthy controls. At the second visit, SNAP participants still had higher scores on the CBCL compared with normally-developing controls, but their performance on the impulsivity task had improved to the point where their results were indistinguishable from the healthy controls. Structural magnetic resonance imaging in the SNAP participants further revealed that improvements in impulsivity were associated with GMV changes in the frontotemporal region. Conclusion: These results suggest that SNAP led to improvement in behavioral measures of impulsivity in a cohort of boys with high externalizing behavior. Improvement in impulsivity was also associated with increased GMV changes. The mechanism behind these brain changes is unknown but could relate to cognitive behavioral therapy and contingency management interventions, important components of SNAP, that target frontotemporal brain regions. Clinically, this study offers new evidence for the potential targeting of brain regions by non-invasive modalities, such as repetitive transcranial magnetic stimulation, to improve externalizing behavior and impulsivity.

Brain-derived neurotrophic factor levels and psychopathology scores in drug-naïve first-episode psychosis

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) is involved in the regulation of many neuronal processes, including neurogenesis. Therefore, it is thought to be closely associated with many psychopathologies with a neurodevelopmental basis, for example, schizophrenia.

METHODS

The patients admitted to the Psychiatry Department of the Faculty of Medicine with a diagnosis of non-affective drug-naïve first-episode psychosis (FEP) were included in the study. The relationship between laboratory and clinical findings and psychometric data (Positive and Negative Syndrome Scale) was examined.

RESULTS

The study population consisted of 34 FEP and 34 healthy control (HC) volunteers. Mean BNDF levels of FEP and HC groups were 14.95 ± 6.13 and 17.89 ± 4.84 pg/ml, respectively. The difference between the groups was statistically significant (t = 2.197; p = .032). There was a negative correlation between mean BDNF levels and PANSS general psychopathology subscale scores (r = .358; p = .038), and total PANSS scores (r = .356; p = .039).

DISCUSSION

There is a consensus on low serum BDNF levels both in FEP and in schizophrenia. However, it is still not clear which clinical findings are associated with lower serum BDNF levels. The relationship between BDNF levels and psychopathologies in schizophrenia has to be investigated.

Ketamine-induced changes in plasma brain-derived neurotrophic factor (BDNF) levels are associated with the resting-state functional connectivity of the prefrontal cortex

OBJECTIVES

Synaptic plasticity and brain-derived neurotrophic factor (BDNF) signalling are proposed to play key roles in antidepressant drug action. Ketamine, an N-methyl-D-aspartate receptor antagonist and putative antidepressant, may increase synaptic plasticity in prefrontal cortex through higher expression of BDNF. Furthermore, ketamine was shown to change resting-state functional connectivity (RSFC) of dorsomedial prefrontal cortex (dmPFC).

METHODS

In a randomised, placebo-controlled study, we investigated acutely (100 min) and at 24 h following subanesthetic ketamine infusion which dmPFC seeded RSFC changes are most strongly associated with plasma BDNF level changes in 53 healthy participants (21 females, age: 24.4 ± 2.9 years) using 7 T-fMRI.

RESULTS

We observed higher relative levels of BDNF 2 h and 24 h after ketamine compared to placebo. Whole-brain regression revealed that the change in BDNF after 24 h was associated with RSFC decreases from dmPFC to posterior cingulate cortex and ventromedial PFC at 24 h and exploratively also at the 100 min measurement point. Follow-up analyses revealed that RSFC reductions following ketamine were restricted to subjects showing increased BDNF levels at 24 h.

CONCLUSIONS

Our findings indicate BDNF level dynamics following ketamine are related to acute and 24 h RSFC changes. Particularly when BDNF increases are observed after ketamine infusion, a disconnection from dmPFC after 24 h is seen and may reflect synaptic plasticity effects.

Treatment effects on neurometabolite levels in schizophrenia: A systematic review and meta-analysis of proton magnetic resonance spectroscopy studies

BACKGROUND

Although there is growing evidence of alterations in the neurometabolite status associated with the pathophysiology of schizophrenia, how treatments influence these metabolite levels in patients with schizophrenia remains poorly studied.

METHODS

We conducted a literature search using Embase, Medline, and PsycINFO to identify proton magnetic resonance spectroscopy studies that compared neurometabolite levels before and after treatment in patients with schizophrenia. Six neurometabolites (glutamate, glutamine, glutamate + glutamine, gamma-aminobutyric acid, N-acetylaspartate, myo-inositol) and six regions of interest (frontal cortex, temporal cortex, parieto-occipital cortex, thalamus, basal ganglia, hippocampus) were investigated.

RESULTS

Thirty-two studies (n = 773 at follow-up) were included in our meta-analysis. Our results demonstrated that the frontal glutamate + glutamine level was significantly decreased (14 groups; n = 292 at follow-up; effect size = -0.35, P = 0.0003; I² = 22%) and the thalamic N-acetylaspartate level was significantly increased (7 groups; n = 184 at follow-up; effect size = 0.47, P < 0.00001; I² = 0%) after treatment in schizophrenia patients. No significant associations were found between neurometabolite changes and age, gender, duration of illness, duration of treatment, or baseline symptom severity.

CONCLUSIONS

The current results suggest that glutamatergic neurometabolite levels in the frontal cortex and neuronal integrity in the thalamus in schizophrenia might be modified following treatment.

Docosahexaenoic Acid: Outlining the Therapeutic Nutrient Potential to Combat the Prenatal Alcohol-Induced Insults on Brain Development

Brain development is markedly affected by prenatal alcohol exposure, leading to cognitive and behavioral problems in the children. Protecting neuronal damage from prenatal alcohol could improve neural connections and functioning of the brain. DHA, a n-3 (ω-3) long-chain PUFA, is involved in the development of neurons. Insufficient concentrations of DHA impair neuronal development and plasticity of synaptic junctions and affect neurotransmitter concentrations in the brain. Alcohol consumption during pregnancy decreases the maternal DHA status and reduces the placental transfer of DHA to the fetus, resulting in less DHA being available for brain development. It is important to know whether DHA could induce beneficial effects on various physiological functions that promote neuronal development. This review will discuss the current evidence for the beneficial role of DHA in protecting against neuronal damage and its potential in mitigating the teratogenic effects of alcohol.

Early changes of serum BDNF and SSRI response in adolescents with major depressive disorder

BACKGROUND

Recent evidence suggests that brain-derived neurotrophic factor (BDNF) levels and their early changes may predict antidepressant response in adults with major depressive disorder (MDD). However, in adolescents, BDNF levels in depression and their changes during antidepressant treatment are relatively unknown. We aimed to investigate whether pre-treatment BDNF levels and their early changes predict antidepressant response in depressed adolescents.

METHODS

The study included 83 MDD adolescents and 52 healthy controls aged 12 to 17 years. All depressed adolescents were treated with escitalopram in an 8 week, open-label trial. Depression severity and serum BDNF level at baseline, and weeks 2 and 8 were measured with the Children's Depression Rating Scale-Revised (CDRS-R) and ELISA, respectively.

RESULTS

Responders showed a significant decrease in BDNF levels at week 2 but non-responders and healthy controls had no changes in BDNF levels at week 2. The early decrease (baseline - week 2) of BDNF levels predicted SSRI response with moderate sensitivity and specificity. Logistic regression analysis revealed that early BDNF decrease predicted SSRI response at week 8 after controlling for other demographic and clinical variables.

LIMITATIONS

The follow-up duration of the study was limited in 8 weeks. It remains possible that serum BDNF levels would have changed with longer treatment.

CONCLUSIONS

This is the first longitudinal study to investigate the effect of antidepressants on BDNF levels in adolescents with MDD. Our findings suggest that a decrease of serum BDNF levels in early phase of SSRI treatment may be associated later SSRI response in adolescents with MDD.

Pathways Connecting Late-Life Depression and Dementia

Late-life depression is associated with significant cognitive impairment. Meta-analyses showed that depression is associated with an increased risk for Alzheimer’s disease (AD) and it might be an etiological factor for AD. Since late-life depression is often connected with cognitive impairment and dementia is usually associated with depressive symptoms, a simple diagnostic approach to distinguish between the disorders is challenging. Several overlapping pathophysiological substrates might explain the comorbidity of both syndromes. Firstly, a stress syndrome, i.e., elevated cortisol levels, has been observed in up to 70% of depressed patients and also in AD pathology. Stress conditions can cause hippocampal neuronal damage as well as cognitive impairment. Secondly, the development of a depression and dementia after the onset of vascular diseases, the profile of cerebrovascular risk factors in both disorders and the impairments depending on the location of cerebrovascular lesions, speak in favor of a vascular hypothesis as a common factor for both disorders. Thirdly, neuroinflammatory processes play a key role in the etiology of depression as well as in dementia. Increased activation of microglia, changes in Transforming-Growth-Factor beta1 (TGF-beta1) signaling, production of pro-inflammatory cytokines as well as reduction of anti-inflammatory molecules are examples of common pathways impaired in dementia and depression. Fourthly, the neurotrophin BDNF is highly expressed in the central nervous system, especially in the hippocampus, where it plays a key role in the proliferation, differentiation and the maintenance of neuronal integrity throughout lifespan. It has been associated not only with antidepressant properties but also a reduction of cognitive impairment and therefore could be involved also in AD. Another etiologic factor is amyloid accumulation, as plasma amyloid beta-42 independently predicts both late-onset depression and AD. Higher plasma amyloid beta-42 predicts the development of late onset depression and conversion to possible AD. However, clinical trials with antibodies against beta amyloid recently failed, i.e., Solanezumab, Aducanumab, and Crenezumab. An overproduction of amyloid-beta might simply reflect a form of synaptic plasticity to compensate for neuronal dysfunction in different kind of neurological and psychiatric diseases of multiple etiologies. The tau hypothesis, sex/gender specific differences, epigenetics and the gut microbiota-brain axis imply other potential common pathways connecting late-life depression and dementia. In conclusion, different potential pathophysiological links between dementia and depression highlight several specific synergistic and multifaceted treatment possibilities, depending on the individual risk profile of the patient.

Acute psychosocial stress increases serum BDNF levels: an antagonistic relation to cortisol but no group differences after mental training

Brain-derived neurotrophic factor (BDNF) is an essential facilitator of neuronal plasticity. By counteracting the adverse effects of excessive stress-induced glucocorticoid signaling, BDNF has been implicated as a resilience factor to psychopathology caused by chronic stress. Insights into the effects of acute stress on peripheral BDNF levels in humans are inconclusive. The short-term interplay between BDNF and cortisol in response to acute psychosocial stress remains unexplored. Furthermore, it is unknown whether mental training that is effective at reducing cortisol reactivity can also influence BDNF during acute stress. In the current study, we investigated serum BDNF levels during an acute psychosocial stress paradigm, the Trier Social Stress Test (TSST), in 301 healthy participants (178 women, mean age = 40.65) recruited as part of the ReSource Project, a large-scale mental training study consisting of three distinct 3-month training modules. Using a cross-sectional study design, we first examined the relationship between BDNF and salivary cortisol in a control group with no mental training. Subsequent analyses focused on differences in BDNF stress levels between control and mental training groups. We show that serum BDNF is indeed stress-sensitive, characterized by a significant post-stress increase and subsequent decline to recovery. While respective increases in BDNF and cortisol were not associated, we found two indications for an antagonistic relationship. Higher BDNF peaks after stress were associated with steeper cortisol recovery. On the other hand, the magnitude of the cortisol stress response was linked to steeper BDNF recovery after stress. BDNF levels were not modulated by any of the mental training modules. Providing novel evidence for the dynamics of BDNF and cortisol during acute stress, our findings may further inform research on the physiological mechanisms involved in stress chronification and the associated health risks.

[Brain-derived neurotrophic factor in multiple sclerosis]

The review presents data on brain-derived neurotrophic factor (BDNF), its structure and functions, the effect on the pathogenesis of experimental autoimmune encephalomyelitis and multiple sclerosis (MS). The correlation of BDNF level with clinical manifestations of MS and the changes of its level during disease-modifying therapy is considered.

Mental health in familial caregivers of Alzheimer's disease patients: are the effects of chronic stress on cognition inevitable?

Familial caregivers of Alzheimer's disease (AD) patients experience an emotional and physical burden which characterizes a chronic stress condition. The resulting hypothalamic-pituitary-adrenal axis dysfunction favors an imbalance of neurotoxic/neuroprotective factors and causes cognitive impairments, increasing the caregivers' risk for cognitive decline and compromising their ability to provide adequate care of the patient. Therefore, the present study aimed to investigate the reversibility of the cognitive impairments of familial caregivers of AD patients during their caregiving-related chronic stress condition. Thirty-three caregivers (61.42 + 2.68 years; 27 women) and thirty-four controls (57.91 ± 2.16 years, 20 women) were evaluated for their cognitive functioning (attention, executive function, processing speed and memory) with a neuropsychological battery (Digit-span, Trail Making, Stroop and the Logical Memory tests). Subjects' cortisol/dehydroepiandrosterone (DHEA) ratios were determined by radioimmunoassay, and their brain-derived neurotrophic factor (BDNF) levels were analyzed by ELISA. An incidental contextual memory task, with or without an associative encoding instruction, was used to investigate if caregivers have a cognitive reserve prone to rehabilitation. The contextual memory impairment of caregivers was associated with prefrontal and hippocampal cognitive dysfunctions, alterations of the cortisol/DHEA ratio and lower BDNF levels. Even so, the contextual memory impairment could be improved by the associative encoding condition. This study suggests that the cognitive impairments of caregivers are not necessarily irreversible, as indicated by the results obtained for contextual memory, which could be improved despite the ongoing chronic stress and associated hormonal and neurotrophin dysfunctions. Lay summary The support of a relative with Alzheimer's Disease submits the familial caregivers to a chronic stress condition that increases their own risk of cognitive decline. This study suggests that, irrespective to their alterations on cortisol/DHEA ratio and BDNF levels, caregivers have a cognitive reserve that could probably be engaged to limit the negative effects of chronic stress on cognition.

Serum and plasma brain-derived neurotrophic factor and response in a randomized controlled trial of riluzole for treatment resistant depression

BACKGROUND

Serum brain-derived neurotrophic factor (BDNF) is decreased in individuals with major depressive disorder (MDD). Pre-clinical and clinical reports suggest that the glutamate release inhibitor riluzole increases BDNF and may have antidepressant properties. Here we report serum (sBDNF) and plasma (pBDNF) levels from a randomized controlled, adjunctive, sequential parallel comparison design trial of riluzole in MDD.

METHODS

Serum and plasma BDNF samples were drawn at baseline and weeks 6 and 8 from 55 subjects randomized to adjunctive treatment with riluzole or placebo for 8 weeks.

RESULTS

Riluzole responders had lower baseline serum (19.08 ng/ml [SD 9.22] v. 28.80 ng/ml [9.63], p = 0.08) and plasma (2.72 ng/ml [1.07] v. 4.60 ng/ml [1.69], p = 0.06) BDNF compared to non-responders at a trend level. This pattern was nominally seen in placebo responders for baseline pBDNF to some degree (1.21 ng/ml [SD 1.29] v. 3.58 ng/ml [SD 1.67], p = 0.12) but not in baseline sBDNF.

LIMITATIONS

A number of limitations warrant comment, including the small sample size of viable BDNF samples and the small number of riluzole responders.

CONCLUSIONS

Preliminary evidence reported here suggests that lower baseline BDNF may be associated with better clinical response to riluzole.

Methylmercury alters the number and topography of NO-synthase positive neurons in embryonic retina: Protective effect of alpha-tocopherol

Vertebrate retina has been shown to be an important target for mercury toxicity and very studies have shown the effect of mercury on the retinal ontogenesis. The nitrergic system plays an important role in the retinal development. The current work studied the effects of methylmercury (MeHg) exposure on the NO-synthase positive neurons (NADPH-diaphorase neurons or NADPH-d+) of the chick retinal ganglion cell layer at embryonic E15 and postnatal P1 days. Retinal flat mounts were stained for NADPH-diaphorase histochemistry and mosaic properties of NADPH-d + were studied by plotting isodensity maps and employing density recovery profile technique. It was also evaluated the protective effect of alpha-tocopherol treatment on retinal tissues exposed to MeHg. MeHg exposure decreased the density of NADPH-d + neurons and altered cell mosaic properties at E15 but had very little or no effect at P1 retinas. Alpha-tocopherol has a protective effect against MeHg exposure at E15. MeHg alterations and alpha-tocopherol protective effect in embryonic retinas were demonstrated to be at work in experimental conditions. MeHg effect in the early phases of visual system development in natural conditions might use the nitrergic pathway and supplementary diet could have a protective effect. At later stages, this mechanism seems to be naturally protected.

Peripheral Blood Brain-Derived Neurotrophic Factor as a Biomarker of Alzheimer's Disease: Are There Methodological Biases?

Mounting evidence that alterations in brain-derived neurotrophic factor (BDNF) levels and signaling may be involved in the etiopathogenesis of Alzheimer's disease (AD) has suggested that its blood levels could be used as a biomarker of the disease. However, higher, lower, or unchanged circulating BDNF levels have all been described in AD patients compared to healthy controls. Although the reasons for such different findings are unclear, methodological issues are likely to be involved. The heterogeneity of participant recruitment criteria and the lack of control of variables that influence circulating BDNF levels regardless of dementia (depressive symptoms, medications, lifestyle, lack of overlap between serum and plasma, and experimental aspects) are likely to bias result and prevent study comparability. The present work reviews a broad panel of factors, whose close control could help reduce the inconsistency of study findings, and offers practical advice on their management. Research directed at elucidating the weight of each of these variables and at standardizing analytical methodologies is urgently needed.

Serial Changes of Cytokines in Children with Cerebral Palsy Who Received Intravenous Granulocyte-colony Stimulating Factor Followed by Autologous Mobilized Peripheral Blood Mononuclear Cells

BACKGROUND

This study was performed to assess serial cytokine changes and their clinical impact in children with cerebral palsy (CP) who received granulocyte-colony stimulating factor (G-CSF) followed by infusion of autologous mobilized peripheral blood mononuclear cells (mPBMCs).

METHODS

Peripheral blood (PB) samples were collected from 16 CP children at enrollment, and 1 month and 7 months after G-CSF infusion as well as at the end of the study. Cytokine levels were measured by enzyme-linked immunosorbent assays with plasma samples.

RESULTS

There were no significant differences in cytokine levels between the mPBMC and placebo groups over 6 months. However, when clinical responders and non-responders were compared, interleukin (IL)-6 (P = 0.050) as well as G-CSF (P = 0.010) were higher in the responders than the non-responders at 1 month, while brain-derived neurotrophic factor (BDNF) (P = 0.030) and insulin-like growth factor (IGF)-1 (P = 0.001) were lower. In addition, BDNF was higher at baseline in the responders than the non-responders (P = 0.030).

CONCLUSION

The changes of G-CSF itself, as well as G-CSF-induced cytokines such as IL-6, may be associated with the clinical improvement of neurologic functions. The G-CSF-induced changes of IL-6, BDNF and IGF-1, and BDNF levels before treatment, could be used as prognostic factors in G-CSF trials in CP children.

Peripheral levels of BDNF and opiate-use disorder: literature review and update

Several neurobiological factors are related to opiate-use disorder (OUD), and among them, neurotrophins have a relevant role. Brain-derived neurotrophic factor (BDNF) is a central neurotrophin involved in many neuronal processes, and it has been related to several psychiatric diseases and addictive disorders. BDNF can be measured in plasma and serum; its levels may reflect BDNF concentrations in the central nervous system (CNS) and, indirectly, CNS processes. Hence, peripheral BDNF could be a biomarker in clinical practice. This manuscript explores the findings about peripheral BDNF and OUD in humans. Opiates induce neurotoxicity in the CNS, which may be correlated with modifications in BDNF expression. Thus, basal levels of peripheral BDNF in OUD patients may be altered, which could be modified with abstinence. Also, opiates may modify epigenetic processes that may be associated with peripheral concentrations of BDNF, and in this line, withdrawal could reflect recovering processes in the CNS. Additionally, treatment modifies the peripheral concentrations of BDNF, but the clinical implications of those changes are yet not elucidated. No specific conclusion can be performed and more investigation in this area is necessary to elucidate the real potential of peripheral BDNF as a biomarker.

Effect of a Comprehensive Intervention on Plasma BDNF in Patients with Alzheimer's Disease

A comprehensive intervention (CI) on patients with Alzheimer’s disease was assessed by measuring plasmabrain-derived neurotrophic factor (pBDNF) and ADAS-Cog score (ADAS-Cog_score) before, immediately after (FU1), and 6 (FU2) and 24 months (FU3) after the CI. Baseline pBDNF was higher in patients with moderate AD (but not mild AD) than in healthy controls. At FU1, pBDNF and ADAS-Cog_score decreased significantly. At FU2 and FU3, patients’ cognitive status worsened and pBDNF further increased versus baseline, suggesting that CI interruption may be a stress event that prevents return to homeostasis. CI exerted positive short-term effects, but more information is needed on long-term consequences.

Application of magnetic resonance spectroscopy in geriatric mood disorders

The prevalence of mood disorders in the rapidly-growing older adult population merits attention due to the likelihood of increased medical comorbidities, risk of hospitalization or institutionalization, and strains placed on caregivers and healthcare providers. Magnetic resonance spectroscopy (MRS) quantifies biochemical compounds in vivo, and has been used specifically for analyses of neural metabolism and bioenergetics in older adults with mood disorders, usually via proton or phosphorous spectroscopy. While yet to be clinically implemented, data gathered from research subjects may help indicate potential biomarkers of disease state or trait or putative drug targets. Three prevailing hypotheses for these mood disorders are used as a framework for the present review, and the current biochemical findings within each are discussed with respect to particular metabolites and brain regions. This review covers studies of MRS in geriatric mood disorders and reveals persisting gaps in research knowledge, especially with regard to older age bipolar disorder. Further MRS work, using higher field strengths and larger sample sizes, is warranted in order to better understand the neurobiology of these prevalent late-life disorders.

Neuroprotective Effect of Modified Electroconvulsive Therapy for Schizophrenia: A Proton Magnetic Resonance Spectroscopy Study

The underlying mechanism of modified electroconvulsive therapy (MECT) treatment for drug-resistant and catatonic schizophrenia remains unclear. Here, we aim to investigate whether MECT exerts its antipsychotic effects through elevating N-acetylaspartate (NAA) concentration measured by proton magnetic resonance spectroscopy (H-MRS). Multiple-voxel H-MRS was acquired in the bilateral prefrontal cortex (PFC) and thalamus to obtain measures of neurochemistry in 32 MECT, 34 atypical antipsychotic-treated schizophrenic patients, and 34 healthy controls. We found that both MECT and atypical antipsychotic treatments showed significant antipsychotic efficacy. MECT and atypical antipsychotic treatments reversed the reduced NAA/creatine ratio (NAA/Cr) in the left PFC and left thalamus in schizophrenic patients compared with healthy controls. Furthermore, the NAA/Cr ratio after treatments was significant higher in the MECT group, but not in the medication group. Our findings demonstrate that eight times of MECT elevated the relative NAA concentration to display neuroprotective effect, which may be the underlying mechanism of rapid antipsychotic efficacy.

Affective alterations in patients with Cushing's syndrome in remission are associated with decreased BDNF and cortisone levels

OBJECTIVE

Affective alterations and poorer quality of life often persist in patients with Cushing's syndrome (CS) in remission. Brain-derived neurotrophic factor (BDNF) regulates the hypothalamic-pituitary-adrenal axis (HPA) and is highly expressed in brain areas controlling mood and response to stress. Our aims were to assess affective alterations after long-term remission of CS and evaluate whether they are associated with serum BDNF, salivary cortisol (SalF) and/or cortisone (SalE) concentrations.

SUBJECTS AND METHODS

Thirty-six CS patients in remission (32 females/4 males; mean age (±s.d.), 48.8 ± 11.8 years; median duration of remission, 72 months) and 36 gender-, age- and BMI-matched controls were included. Beck Depression Inventory-II (BDI-II), Center for Epidemiological Studies Depression Scale (CES-D), Positive Affect Negative Affect Scale (PANAS), State-Trait Anxiety Inventory (STAI), Perceived Stress Scale (PSS) and EuroQoL and CushingQoL questionnaires were completed and measured to evaluate anxiety, depression, stress perception and quality of life (QoL) respectively. Salivary cortisol was measured using liquid chromatography/tandem mass spectrometry (LC/TMS). BDNF was measured in serum using an ELISA.

RESULTS

Remitted CS patients showed worse scores in all questionnaires than controls: STAI (P < 0.001), BDI (P < 0.001), CES-D (P < 0.001), PANAS (P < 0.01), PSS (P < 0.01) and EuroQoL (P < 0.01). A decrease in BDNF was observed in CS vs controls (P = 0.038), and low BDNF was associated with more anxiety (r = -0.247, P = 0.037), depression (r = -0.249, P = 0.035), stress (r = -0.277, P = 0.019) and affective balance (r = 0.243, P = 0.04). Morning salivary cortisone was inversely associated with trait anxiety (r = -0.377, P = 0.040) and depressed affect (r = -0.392, P = 0.032) in CS patients. Delay to diagnosis was associated with depressive symptoms (BDI-II: r = 0.398, P = 0.036 and CES-D: r = 0.449, P = 0.017) and CushingQoL scoring (r = -0.460, P < 0.01).

CONCLUSIONS

Low BDNF levels are associated with affective alterations in 'cured' CS patients, including depression, anxiety and impaired stress perception. Elevated levels of SalE might also be related to poor affective status in these patients.

A biological perspective on differences and similarities between burnout and depression

To compare and contrast burnout and depression is not only a conceptual issue, but may deliver important directions for treatment approaches and stabilize the awareness of disease which is essential for affected individuals. Because of the symptomatic overlap, it is a subject of multidimensional research and discussion to find specific signatures to differentiate between the two phenomena or to present evidence that they are different aspects of the same disorder. Both pathologies are regarded as stress-related disorders. Therefore, in this review burnout and depression are discussed on the basis of biological parameters, mainly heart rate variability (HRV) and brain-derived neurotrophic factor (BDNF), which are crucial to the stress response system. It emerges that instead of finding one specific discriminating marker, future research should rather concentrate on elaborating indices for burnout and depression which integrate combinations of parameters found in genetics, neurobiology, physiology and environment.

Brain-Derived Neurotrophic Factor Serum Levels and Hippocampal Volume in Mild Cognitive Impairment and Dementia due to Alzheimer Disease

Background/Aims

Hippocampal atrophy is a recognized biomarker of Alzheimer disease (AD) pathology. Serum brain-derived neurotrophic factor (BDNF) reduction has been associated with neurodegeneration. We aimed to evaluate BDNF serum levels and hippocampal volume in clinical AD (dementia and mild cognitive impairment [MCI]).

Methods

Participants were 10 patients with MCI and 13 with dementia due to AD as well as 10 healthy controls. BDNF serum levels were determined by ELISA and volumetric measures with NeuroQuant®.

Results

MCI and dementia patients presented lower BDNF serum levels than healthy participants; dementia patients presented a smaller hippocampal volume than MCI patients and healthy participants.

Discussion

The findings support that the decrease in BDNF might start before the establishment of neuronal injury expressed by the hippocampal reduction.

Increased BDNF levels after electroconvulsive therapy in patients with major depressive disorder: A meta-analysis study

OBJECTIVE

We performed a systematic review and meta-analysis to estimate brain-derived neurotrophic factor (BDNF) level in patients with major depressive disorder (MDD) after electroconvulsive therapy (ECT).

METHOD

A comprehensive search of the Cochrane Library, MEDLINE, LILACS, Grey literature, and EMBASE was performed for papers published from January 1990 to April 2016. The following key terms were searched: "major depressive disorder", "unipolar depression", "brain-derived neurotrophic factor", and "electroconvulsive therapy".

RESULTS

A total of 252 citations were identified by the search strategy, and nine studies met the inclusion criteria of the meta-analysis. BDNF levels were increased among patients with MDD after ECT (P value = 0.006). The standardized mean difference was 0.56 (95% CI: 0.17-0.96). Additionally, we found significant heterogeneity between studies (I² = 73%).

CONCLUSION

Our findings suggest a potential role of BDNF as a marker of treatment response after ECT in patients with MDD.

Brain-Derived Neurotrophic Factor and Suicide in Schizophrenia: Critical Role of Neuroprotective Mechanisms as an Emerging Hypothesis

Suicide is a common occurrence in psychiatric disorders and is a cause of increased healthcare utilization worldwide. Schizophrenia is one of the most common psychiatric disorders worldwide and posited to be seen in 1% of the population worldwide. Suicide is a common occurrence in schizophrenia with 25%-30% patients with schizophrenia attempting suicide and 8%-10% completing it. There is a need for valid biological markers to help clinicians identify patients with schizophrenia that may be at a risk of suicide and thus help in them receiving better care and interventions at the earliest even before a suicide attempt occurring. There are clear neurobiological changes at a genetic, neuroimaging, and neurochemical level that occurs in patients with schizophrenia that attempt suicide. There is a new theory that postulates neuronal plasticity and neuroprotection to have a role in the biological changes that ensue when suicidal thoughts and feelings occur in patients with schizophrenia. Neurotrophic growth factors like brain-derived neurotrophic factor (BDNF) have been documented to play a role in the protection of neurons and in the prevention of neurobiological changes that may lead to suicide both in schizophrenia and depression. The present paper presents a commentary that looks at the role of BDNF as a protective factor and neurobiological marker for suicide in schizophrenia.

The human BDNF gene: peripheral gene expression and protein levels as biomarkers for psychiatric disorders

Brain-derived neurotrophic factor (BDNF) regulates the survival and growth of neurons, and influences synaptic efficiency and plasticity. The human BDNF gene consists of 11 exons, and distinct BDNF transcripts are produced through the use of alternative promoters and splicing events. The majority of the BDNF transcripts can be detected not only in the brain but also in the blood cells, although no study has yet investigated the differential expression of BDNF transcripts at the peripheral level. This review provides a description of the human BDNF gene structure as well as a summary of clinical and preclinical evidence supporting the role of BDNF in the pathogenesis of psychiatric disorders. We will discuss several mechanisms as possibly underlying BDNF modulation, including epigenetic mechanisms. We will also discuss the potential use of peripheral BDNF as a biomarker for psychiatric disorders, focusing on the factors that can influence BDNF gene expression and protein levels. Within this context, we have also characterized, for we believe the first time, the expression of BDNF transcripts in the blood, with the aim to provide novel insights into the molecular mechanisms and signaling that may regulate peripheral BDNF gene expression levels.

Decreased Brain-Derived Neurotrophic Factor Serum Concentrations in Chronic Post-Stroke Subjects

BACKGROUND

Brain-derived neurotrophic factor (BDNF) plays a critical role in sensorimotor recovery after a stroke. However, few studies have assessed the circulating BDNF levels in post-stroke humans to understand its changes. This study was conducted to measure BDNF serum concentrations in subjects with chronic hemiparesis, as well as to correlate serum concentrations with age, post-stroke time, total score of Stroke Specific Quality of Life Scale (SS-QOL), mobility subscale score, and motor function of SS-QOL.

METHODS

Seventeen chronic post-stroke subjects matched by age and gender with healthy controls took part in the study. Personal data (age, hemiparesis side, and post-stroke time) were collected, and a physical examination (weight, height, body mass index) and SS-QOL assessment were carried out. On the same day, after the initial evaluation, venous blood samples were collected from the chronic post-stroke subjects and the healthy subjects. The BDNF serum concentrations were measured blindly by enzyme-linked immunosorbent assay.

RESULTS

Subjects with chronic hemiparesis presented a decrease in BDNF serum compared with healthy subjects (P < .01). There was no correlation between BDNF serum levels with post-stroke time, age or quality of life, mobility, and the upper extremity motor function (P > .05). BDNF concentrations are related to structural and functional recovery after stroke; thus, this reduction is important to understand the rehabilitation process more clearly. However, more studies are needed considering the genetic variations and other tools to assess motor impairment and functional independence.

CONCLUSION

Chronic post-stroke subjects presented a decrease in BDNF serum concentrations, without a correlation with post-stroke time, age, and quality of life.

Biomarkers in schizophrenia: A focus on blood based diagnostics and theranostics

Identifying biomarkers that can be used as diagnostics or predictors of treatment response (theranostics) in people with schizophrenia (Sz) will be an important step towards being able to provide personalized treatment. Findings from the studies in brain tissue have not yet been translated into biomarkers that are practical in clinical use because brain biopsies are not acceptable and neuroimaging techniques are expensive and the results are inconclusive. Thus, in recent years, there has been search for blood-based biomarkers for Sz as a valid alternative. Although there are some encouraging preliminary data to support the notion of peripheral biomarkers for Sz, it must be acknowledged that Sz is a complex and heterogeneous disorder which needs to be further dissected into subtype using biological based and clinical markers. The scope of this review is to critically examine published blood-based biomarker of Sz, focusing on possible uses for diagnosis, treatment response, or their relationship with schizophrenia-associated phenotype. We sorted the studies into six categories which include: (1) brain-derived neurotrophic factor; (2) inflammation and immune function; (3) neurochemistry; (4) oxidative stress response and metabolism; (5) epigenetics and microRNA; and (6) transcriptome and proteome studies. This review also summarized the molecules which have been conclusively reported as potential blood-based biomarkers for Sz in different blood cell types. Finally, we further discusses the pitfall of current blood-based studies and suggest that a prediction model-based, Sz specific, blood oriented study design as well as standardize blood collection conditions would be useful for Sz biomarker development.

Neuroscience-informed Auditory Training in Schizophrenia: A Final Report of the Effects on Cognition and Serum Brain-Derived Neurotrophic Factor

Objective

We previously reported the interim effects in a per protocol analysis of a randomized controlled trial of an innovative neuroscience-informed computerized cognitive training approach in schizophrenia. Here we report the effects of training on behavioral outcome measures in our final sample using an intent-to-treat analysis. We also report the effects on serum brain-derived neurotrophic factor (BDNF).

Method

Eighty-seven clinically stable participants with schizophrenia were randomly assigned to either targeted auditory training (AT, N=46) or a computer games control condition (CG, N=41). Participants were assessed on neurocognition, symptoms and functional outcome at baseline and after 50 hours of intervention delivered over 10 weeks. Serum BDNF was assessed at baseline, at 2 weeks, and at 10 weeks.

Results

After the intervention, AT participants showed significant gains in global cognition, speed of processing, verbal learning, and verbal memory, relative to CG participants, with no changes in symptoms or functioning. At baseline, schizophrenia participants had significantly lower-than-normal serum BDNF. AT participants showed a significant increase in serum BDNF compared to CG participants, and “normalized” levels by post training.

Conclusions

Participants with chronic schizophrenia made significant cognitive gains after 50 hours of intensive computerized training delivered as a stand-alone treatment, but no improvement in symptoms or functioning. Serum BDNF levels were significantly increased, and may serve as a peripheral biomarker for the effects of training. Future research must focus on: 1) Methods of integrating cognitive training with psychosocial treatments; 2) A deeper understanding of underlying neurophysiology in order to enhance critical mechanisms of action.

Decreased right hippocampal volumes and neuroprogression markers in adolescents with bipolar disorder

OBJECTIVES

The aim of the present study was to assess differences and correlations between the hippocampal volumes (HCVs), serum nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) levels in adolescents with bipolar disorder (BP) compared to healthy controls.

METHODS

Using structural magnetic resonance imaging, we compared HCVs of 30 patients with euthymic BP who were already enrolled in a naturalistic clinical follow-up. For comparison, we enrolled 23 healthy controls between the ages of 13 and 19. The boundaries of the hippocampus were outlined manually. The BDNF and NGF serum levels were measured with the sandwich ELISA.

RESULTS

The groups did not differ in the right or left HCVs or in the NGF or BDNF serum levels. However, negative correlations were found between the right HCVs and the duration of the disorder and medication and positive correlations were found between the duration of the medications and the NGF and BDNF levels in the patient group. Additionally, positive correlations were found between the follow-up period and left normalized HCVs in both the BP and lithium-treated groups.

CONCLUSIONS

The right HCVs may vary with illness duration and the medication used to treat BP; NGF and BDNF levels may be affected by long-term usage. Further research is needed to determine whether these variables and their structural correlates are associated with clinical or functional differences between adolescents with BP and healthy controls.

Role of calcium, glutamate and NMDA in major depression and therapeutic application

Major depression is a common, recurrent mental illness that affects millions of people worldwide. Recently, a unique fast neuroprotective and antidepressant treatment effect has been observed by ketamine, which acts via the glutamatergic system. Hence, a steady accumulation of evidence supporting a role for the excitatory amino acid neurotransmitter (EAA) glutamate in the treatment of depression has been observed in the last years. Emerging evidence indicates that N-methyl-D-aspartate (NMDA), group 1 metabotropic glutamate receptor antagonists and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) agonists have antidepressant properties. Indeed, treatment with NMDA receptor antagonists has shown the ability to sprout new synaptic connections and reverse stress-induced neuronal changes. Based on glutamatergic signaling, a number of therapeutic drugs might gain interest in the future. Several compounds such as ketamine, memantine, amantadine, tianeptine, pioglitazone, riluzole, lamotrigine, AZD6765, magnesium, zinc, guanosine, adenosine aniracetam, traxoprodil (CP-101,606), MK-0657, GLYX-13, NRX-1047, Ro25-6981, LY392098, LY341495, D-cycloserine, D-serine, dextromethorphan, sarcosine, scopolamine, pomaglumetad methionil, LY2140023, LY404039, MGS0039, MPEP, 1-aminocyclopropanecarboxylic acid, all of which target this system, have already been brought up, some of them recently. Drugs targeting the glutamatergic system might open up a promising new territory for the development of drugs to meet the needs of patients with major depression.

Plasma brain-derived neurotrophic factor levels in patients suffering from post-traumatic stress disorder

A number of studies have been done to investigate the role of brain-derived neurotrophic factor (BDNF) in patients with post-traumatic stress disorder (PTSD). In this study we aimed to test the relationship between plasma BDNF levels and PTSD. We solicited 65 subjects having recently experienced road traffic accidents (RTA) conforming to screening criteria. They were given follow-up examinations after one month, three months, and six months. PTSD was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-R-TR, American Psychiatric Association, 2000) using the Mini International Neuropsychiatric Interview (MINI). All participants were divided into two groups: a group with PTSD and a group without PTSD. There were no significant differences in plasma BDNF levels between the two groups at either the 48h or six-month examination. Within the PTSD group, no significant differences were found in plasma BDNF levels between the two examinations. BDNF levels in those without PTSD showed a higher trend over time after trauma. Higher BDNF levels may be an important protective factor for the prevention of traumatized subjects from developing PTSD.