Stress at work alters serum brain-derived neurotrophic factor (BDNF) levels and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in healthy volunteers: BDNF and MHPG as possible biological markers of mental stress?

Plasma and Platelet Brain-Derived Neurotrophic Factor (BDNF) Levels in Bipolar Disorder Patients with Post-Traumatic Stress Disorder (PTSD) or in a Major Depressive Episode Compared to Healthy Controls

Post-traumatic stress disorder (PTSD) is a highly disabling mental disorder arising after traumatism exposure, often revealing critical and complex courses when comorbidity with bipolar disorder (BD) occurs. To search for PTSD or depression biomarkers that would help clinicians define BD presentations, this study aimed at preliminarily evaluating circulating brain-derived-neurotrophic factor (BDNF) levels in BD subjects with PTSD or experiencing a major depressive episode versus controls. Two bloodstream BDNF components were specifically investigated, the storage (intraplatelet) and the released (plasma) ones, both as adaptogenic/repair signals during neuroendocrine stress response dynamics. Bipolar patients with PTSD (n = 20) or in a major depressive episode (n = 20) were rigorously recruited together with unrelated healthy controls (n = 24) and subsequently examined by psychiatric questionnaires and blood samplings. Platelet-poor plasma (PPP) and intraplatelet (PLT) BDNF were measured by ELISA assays. The results showed markedly higher intraplatelet vs. plasma BDNF, confirming platelets' role in neurotrophin transport/storage. No between-group PPP-BDNF difference was reported, whereas PLT-BDNF was significantly reduced in depressed BD patients. PLT-BDNF negatively correlated with mood scores but not with PTSD items like PPP-BDNF, which instead displayed opposite correlation trends with depression and manic severity. Present findings highlight PLT-BDNF as more reliable at detecting depression than PTSD in BD, encouraging further study into BDNF variability contextually with immune-inflammatory parameters in wider cohorts of differentially symptomatic bipolar patients.

Serum brain-derived neurotrophic factor concentration is different between autism spectrum disorders and intellectual disability children and adolescents

PURPOSE

Recent studies showed that mature brain-derived neurotrophic factor (mBDNF) and its precursor proBDNF are associated with autism spectrum disorders (ASD). Whether their levels are different between ASD and intellectual disability (ID) subjects is not clear. The aim of this study is to compare the serum mBDNF and proBDNF concentration, and mBNDF/proBDNF ratio in ASD and ID volunteers.

METHODS

Children and adolescents with ASD or ID between the ages of 4 and 22 were recruited in Tianjin, China. Serum mBDNF and proBDNF level were tested and Wechsler Preschool and Primary Scale of Intelligence (WPPSI), Wechsler Intelligence Scale for Children (WISC), and Childhood Autism Rating Scale (CARS) evaluations were conducted.

RESULTS

Serum mBDNF concentration and the ratio of mBDNF to proBDNF was higher in ASD subjects than that in ID subjects (P = 0.035 and P < 0.001, respectively), while serum proBDNF of ASD participants was lower compared to that of ID participants (P < 0.001). CARS score was positively correlated with serum mBDNF level (r = 0.33, P = 0.004) and m/p ratio (r = 0.39, P < 0.001), and negatively correlated with serum proBDNF level (r = -0.39, <0.001) after adjusting for age and IQ. The AUC of mBDNF, proBDNF, and m/p ratio were 0.741, 0.790, and 0.854, respectively, after adjusted for age and IQ.

CONCLUSION

Serum mBDNF, proBDNF and m/p ratio were different between ASD and ID group. The three biomarkers displayed good diagnostic values for classification of ASD and ID subjects.

Association between salivary mature brain-derived neurotrophic factor and psychological distress in healthcare workers

INTRODUCTION

Previous studies have suggested association between brain-derived neurotrophic factor (BDNF) and the stress level of workers. However, no studies have investigated the potential of salivary mature BDNF (mBDNF) level as a noninvasive biomarker for psychological distress. This study aimed to explore the reliability of salivary mBDNF as a biomarker for psychological distress in healthcare workers. Furthermore, we examined the relationship between salivary and plasma mBDNF levels and their correlation with age, sex, body mass index (BMI), and exercise habits.

METHODS

Fifty-one healthy healthcare workers (26 men) from the University of Occupational and Environmental Health, Japan, participated in this study. In this cross-sectional study, participants provided demographic information. Psychological distress was assessed using the Kessler 6 (K6). Saliva and blood samples were collected, and mBDNF was measured by ELISA. Spearman's rank correlation coefficient was performed to analyze the relationship between mBDNF (saliva and plasma) and K6. Statistical analyses were conducted using Stata 17.0, and a significance level of p < .05 was applied.

RESULTS

The median K6 score was 1 (interquartile range [IQR]: 0-3). The median (IQR) salivary mBDNF was 1.36 (1.12-1.96) pg/mL, whereas the mean (standard deviation) plasma mBDNF was 1261.11 (242.98) pg/mL. No correlation was observed between salivary and plasma mBDNF concentrations or with the K6 score. Additionally, there were no associations between salivary or plasma mBDNF concentrations and age, sex, or exercise habits. Finally, an association between plasma mBDNF concentration and BMI was found only in univariate analysis.

CONCLUSION

Our findings indicate that salivary mBDNF can be accurately measured noninvasively in healthcare workers. Within our study sample, salivary mBDNF did not demonstrate any correlation with K6 and plasma mBDNF. Future studies with a larger study sample and a diverse study population consisting of healthy participants and patients with psychiatric disorders are warranted.

The Effects of Walnuts and Academic Stress on Mental Health, General Well-Being and the Gut Microbiota in a Sample of University Students: A Randomised Clinical Trial

Poorer mental health is common in undergraduate students due to academic stress. An interplay between stress and diet exists, with stress influencing food choices. Nutritional interventions may be effective in preventing mental health decline due to complex bidirectional interactions between the brain, the gut and the gut microbiota. Previous studies have shown walnut consumption has a positive effect on mental health. Here, using a randomized clinical trial (Australian New Zealand Clinical Trials Registry, #ACTRN12619000972123), we aimed to investigate the effects of academic stress and daily walnut consumption in university students on mental health, biochemical markers of general health, and the gut microbiota. We found academic stress had a negative impact on self-reported mood and mental health status, while daily walnut consumption improved mental health indicators and protected against some of the negative effects of academic stress on metabolic and stress biomarkers. Academic stress was associated with lower gut microbial diversity in females, which was improved by walnut consumption. The effects of academic stress or walnut consumption in male participants could not be established due to small numbers of participants. Thus, walnut consumption may have a protective effect against some of the negative impacts of academic stress, however sex-dependent mechanisms require further study.

The effect of zinc supplementation on brain derived neurotrophic factor: A meta-analysis

BACKGROUND

Zinc in one of the most abundant trace minerals in human body which is involved in numerous biological pathways and has variety of roles in the nervous system. It has been assumed that zinc exerts its role in nervous system through increasing brain derived neurotrophic factor (BDNF) concentrations.

OBJECTIVES

Present meta-analysis was aimed to review the effect of zinc supplementation on serum concentrations of BDNF.

METHODS AND MATERIALS

Four electronic databases (Pubmed, Scopus, Web of Science, Embase) were searched for identifying studies that examined BDNF levels prior and after zinc supplementation up to May 2020. According to the Cochrane guideline, a meta-analysis was performed to pool the effect size estimate (Hedges' test) of serum BDNF across studies. Risk of publication bias was assessed using a funnel plot and Egger's test.

RESULTS

Five studies were eligible and 238 participants were included. These studies enrolled subjects with premenstrual syndrome, diabetic retinopathy, major depression disorder, overweight/obese and obese with mild to moderate depressive disorders. Zinc supplementation failed to increase blood BDNF concentrations with effect size of 0.30 (95 % CI: -0.08, 0.67, P = 0.119). Funnel plot did not suggest publication bias.

CONCLUSION

Zinc supplementation may not significantly increase BDNF levels. However, the small number of included articles and significant heterogeneity between them can increase the risk of a false negative result; therefore, the results should be interpreted with caution.

Upregulating Effect of Wheat on Brain-Derived Neurotrophic Factor in Human Lung Adenocarcinoma A549 Cells

The neurotrophic hypothesis of depression, that is, a deficiency in hippocampal brain-derived neurotrophic factor (BDNF) leads to depression, has gained widespread acceptance. BDNF is synthesized in various peripheral tissues such as the lung, kidney, liver, heart and testis, besides the brain. Peripheral BDNF can traverse the blood-brain barrier and reach the hippocampus; accordingly, substances that upregulate BDNF production in peripheral tissues may be useful in the treatment of depression. The Mediterranean diet, containing high amounts of whole grains including unrefined wheat, vegetables, fruits, nuts, and olive oil, reportedly reduces the risk of depression. The association between the high consumption of unrefined wheat in the Mediterranean diet and BDNF production in peripheral tissues is unclear. In this study, we investigated the BDNF production capacity of human lung adenocarcinoma cell line A549 and the effect of wheat on BDNF production in the cells. Methanol extracts of whole-wheat flour and wheat bran, which are forms of unrefined wheat, increased the BDNF level in the culture medium of A549 cells. However, methanol extract of wheat endosperm had no effect on the BDNF level in these cells. Our findings suggest that wheat bran contains ingredients that upregulate BDNF production in peripheral tissues, and unrefined wheat potentially contributes to the elevation in peripheral BDNF level.

Nurse Work Environment and Stress Biomarkers: Possible Implications for Patient Outcomes

OBJECTIVE

To examine associations between nurse work environment, serum biomarkers, and patient outcomes in a large hospital.

METHODS

A work environment questionnaire was administered in 2017 to the total sample of nurses in a Midwestern hospital. A subsample of nurses (n = 83) provided blood samples. Correlation analyses examined associations between work environment ratings, biomarkers (dehydroepiandrosterone-sulphate [DHEA-S] and interleukin-6 [IL-6]), and unit-level patient outcomes.

RESULTS

Work stress was negatively correlated with DHEA-S (r = -0.23) and positively correlated with IL-6 (r = 0.31; P < 0.05). Psychological safety (r = 0.22) and competence development (r = 0.25) were both positively correlated with DHEA-S (P < 0.05). DHEA-S was negatively correlated with central line-associated bloodstream infections (rho = -0.61; P < 0.05).

CONCLUSIONS

Work environment-associated physiological mechanisms might adversely impact patient safety, in addition to nurse health.

Brain-derived neurotrophic factor (BDNF) expression and function in the mammalian reproductive Tract

BACKGROUND

Neurotrophins of the nerve growth factor family are soluble polypeptides that are best known for their role in nerve growth, survival and differentiation in the central nervous system. A growing body of literature shows that neurotrophins and their receptors are also expressed throughout the reproductive tract.

OBJECTIVE AND RATIONALE

Neurotrophins are key regulatory proteins in reproductive physiology during development and throughout adult life. Of the neurotrophins, the literature describing the expression and function of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, neurotrophin receptor kinase-2 (NTRK2), has been expanding rapidly. We therefore conducted a systematic inductive qualitative review of the literature to better define the role of the BDNF in the reproductive tract. We postulate that BDNF and NTRK2 are central regulatory proteins throughout the reproductive system.

SEARCH METHODS

An electronic search of Medline (PubMed) and Web of Science for articles relating to BDNF and the reproductive system was carried out between January 2018 and February 2019.

OUTCOMES

In the ovary, BDNF expression and levels have been linked with follicle organisation during ovarian development, follicle recruitment and growth and oocyte maturation. In the endometrium, BDNF is involved in cell proliferation and neurogenesis. In contrast, literature describing the role of BDNF in other reproductive tissues is sparse and BDNF-NTRK2 signalling in the male reproductive tract has been largely overlooked. Whilst estradiol appears to be the primary regulator of BDNF expression, we also identified reports describing binding sites for glucocorticoid and myocyte enhancer factor-2, a calcium-response element through activation of an N-methyl-D-aspartate (NMDA) receptor, and aryl hydrocarbon receptor nuclear transporter protein-4 (ARNT) response elements in promoter regions of the BDNF gene. Expression is also regulated by multiple microRNAs and post-translational processing of precursor proteins and intracellular shuttling. BDNF-NTRK2 signalling is modulated through tissue specific receptor expression of either the full-length or truncated NTRK2 receptor; however, the functional importance remains to be elucidated. Dysregulation of BDNF expression and circulating concentrations have been implicated in several reproductive disorders including premature ovarian failure, endometriosis, pre-eclampsia, intra-uterine growth restriction (IUGR) and several reproductive cancers.

WIDER IMPLICATIONS

We conclude that BDNF and its receptors are key regulatory proteins central to gonadal development, ovarian regulation and uterine physiology, as well as embryo and placenta development. Furthermore, dysregulation of BDNF-NTRK2 in reproductive diseases suggests their potential role as candidate clinical markers of disease and potential therapeutic targets.

Factors affecting stability of plasma brain-derived neurotrophic factor

Circulating concentrations of brain-derived neurotrophic factor (BDNF) have been linked to cancer, neuropsychiatric, diabetes, and gynecological disorders. However, factors influencing plasma storage and subsequent BDNF quantification are incompletely understood. Therefore, the anticoagulant used in plasma separator tubes, storage-time, storage-temperature, and repeated freeze–thaw cycles on circulating BDNF concentrations was evaluated. Peripheral blood samples were collected from healthy women (n = 14) and men (n = 10) recruited prospectively from McMaster University (August 2014). Blood was collected from the cubital vein into plasma separator tubes containing five different anticoagulant systems [K2EDTA, Li-Hep, Li-Hep (gel), Na-Hep, Na-Hep (glass)], and placed on ice for transport to the lab for centrifugation. Plasma samples (n = 16) collected in K2EDTA tubes from women recruited to a previous study (April 2011 to December 2012) were used to determine the effect of multiple freeze–thaw cycles. Plasma BDNF was quantified using a commercially available ELISA kit. Plasma concentrations of BDNF were significantly affected by the type of plasma separator tube, storage-time, and number of freeze–thaw cycles. Storage temperature (− 20 vs. − 80 °C) did not significantly affect the quantity of BDNF measured as mean BDNF concentrations generally fell within our calculated acceptable change limit up to 6 months in the freezer. Our results suggest that for quantification of circulating BDNF blood collected in K2EDTA tubes and plasma stored up to 6 months at either − 20 or − 80 °C produces reproducible results that fall within an acceptable range. However, plasma samples stored beyond 6 months and repeated freeze–thaw cycles should be avoided.

Comparing the Efficacy of Anodal, Cathodal, and Sham Transcranial Direct Current Stimulation on Brain-Derived Neurotrophic Factor and Psychological Symptoms in Opioid-Addicted Patients

Introduction:

Today, addiction to opioids is a serious problem all over the world. Unfortunately, the consumption of these drugs and the number of addicted people have drastically increased. This research aimed at comparing the efficacy of anodal, cathodal, and sham transcranial Direct Current Stimulation (tDCS) on the Brain-Derived Neurotrophic Factor (BDNF) and psychological symptoms in opioid-addicted patients.

Methods:

Thirty opioid-addicted patients were selected based on the Diagnostic and Statistical Manual of Mental Disorders, the Fifth Edition, through the convenience sampling method. They were then randomly assigned to 3 groups (10 in each group). The subjects were evaluated before and after tDCS by their serum level of BDNF, desires for drug questionnaire, and depression anxiety stress scale. The data were analyzed by the Kolmogorov-Smirnov test, one-way analysis of variance, as well as the Bonferroni test.

Results:

Stimulating the Dorsolateral Prefrontal Cortex (DLPFC) led to a significant change in increasing the level of BDNF (P=0.031) and reducing the degree of depression (P=0.018), anxiety (P=0.001), stress (P=0.012), and decreased the level of craving (P=0.001) in opioid-addicted patients. There was no significant difference between active stimulation groups (anodal left/cathodal right and anodal right/cathodal left). The stimulation of the right DLPFC (group B) significantly increased BDNF in comparison with the sham group (sham tDCS) and decreased anxiety and craving. Nonetheless, no change was observed in depression and stress. The stimulation of the left DLPFC (group A) significantly reduced depression, anxiety, stress, and craving compared with the sham group, while there was no change in BDNF.

Conclusion:

In addition to the conventional treatments of opioid-addicted patients, tDCS is an effective complementary treatment.

Growth factors and neurotrophins in patients with stress-related exhaustion disorder

Growth factors, such as vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF), and neurotrophic factors, including brain-derived neurotophic factor (BDNF), have attracted attention in studies of the biological effects of long-term stress exposure due to their neuroprotective roles. This study investigated whether circulating levels of EGF, VEGF and BDNF were altered in individuals with stress-related exhaustion disorder. Forty patients diagnosed with exhaustion disorder and 40 healthy subjects (50% women) provided fasting blood samples for analysis of EGF, VEGF, and BDNF in plasma. We found significantly lower levels of EGF, VEGF, and BDNF in patients with ED compared to healthy controls. This pattern was seen in both male and female patients. Given the important roles of BDNF and VEGF for brain plasticity and neurogenesis, decreased levels after long-term stress exposure could indicate increased risk of neuronal damage and cognitive impairments in this patient group.

A Critical Evaluation of Wet Biomarkers for Huntington's Disease: Current Status and Ways Forward

There is an unmet clinical need for objective biomarkers to monitor disease progression and treatment response in Huntington's disease (HD). The aim of this review is, therefore, to provide practical advice for biomarker discovery and to summarise studies on biofluid markers for HD. A PubMed search was performed to review literature with regard to candidate saliva, urine, blood and cerebrospinal fluid biomarkers for HD. Information has been organised into tables to allow a pragmatic approach to the discussion of the evidence and generation of practical recommendations for future studies. Many of the markers published converge on metabolic and inflammatory pathways, although changes in other analytes representing antioxidant and growth factor pathways have also been found. The most promising markers reflect neuronal and glial degeneration, particularly neurofilament light chain. International collaboration to standardise assays and study protocols, as well as to recruit sufficiently large cohorts, will facilitate future biomarker discovery and development.

Plasma Brain-Derived Neurotrophic Factor (BDNF) and serum cortisol levels in a sample of workers exposed to occupational stress and suffering from Adjustment Disorders

INTRODUCTION

Decreased plasma BDNF (pBDNF) levels have been proposed as a biomarker in illness phases of mood disorders. Serum cortisol (seC) levels are an index of energy mobilization and stress. The aim of this cross-sectional study was to evaluate pBDNF and seC levels in workers exposed to occupational stress and suffering from Adjustment Disorders (AD) compared to healthy workers.

METHODS

Plasma BDNF and seC levels were measured by means of specific immunoassays in 64 AD patients and 38 healthy controls. Perceived and occupational stress was evaluated in patients and controls using the Psychological Stress Measure (PSM) and the Job Content Questionnaire (JCQ). Psychopatological symptoms in patients were assessed using specific rating scales.

RESULTS

Plasma BDNF levels resulted significantly higher in patients than in controls, whereas no significant differences were found for seC levels. In patients but not in controls pBDNF levels showed a significant positive correlation with seC levels. Perceived stress levels were positively correlated with all psychopatological rating scales scores.

CONCLUSIONS

BDNF could play a key role in the pathophysiology of stress-related disorders and its peripheral levels elevation could contribute to protect neurons under stress. Further research is needed focusing on biomarkers for stress-related disorders as a potential tool for the diagnosis and prevention of occupational diseases.

Association of serum BDNF levels and the BDNF Val66Met polymorphism with the sleep pattern in healthy young adults

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is widely expressed in the brain and plays an important role in neuronal maintenance, plasticity, and neurogenesis. Prior studies have found that decreased serum BDNF levels are associated with perceived stress, depression, or sleep disturbances in humans.

STUDY OBJECTIVES

To elucidate whether the serum BDNF levels and BDNF genotype were associated with the sleep pattern in healthy young adults.

METHODS

The study group consisted of 79 healthy paid volunteers (45 men, 34 women) aged 20 to 29 years. Serum BDNF levels were measured with an enzyme-linked immunosorbent assay, and a single-nucleotide polymorphism (Val66Met) in the BDNF gene was assessed with a TaqMan assay. Details of the sleep pattern were obtained from 1-week sleep/wake records.

RESULTS

Serum BDNF levels were significantly associated with sleep parameters on weekends, whereas no such association was found on weekdays. On weekends, longer total sleep time and time in bed, and later mid-sleep time were associated with lower serum BDNF levels. The difference between mid-sleep time on weekdays and that on weekends, otherwise known as social jetlag, was negatively associated with serum BDNF levels. Met/Met homozygotes of the BDNF Val66Met polymorphism had significantly longer time in bed on weekends than Val/Val homozygotes. Heterozygotes did not differ from Val/Val homozygotes.

CONCLUSIONS

We first found that serum BDNF levels and the BDNF Val66Met polymorphism in healthy young adults were associated with the sleep pattern on weekends but not with that on weekdays, suggesting that the systems involved in BDNF control may be linked to endogenous sleep characteristics rather than the socially constrained sleep schedule in healthy young adults.

Heart rate variability is associated with psychosocial stress in distinct social domains

OBJECTIVE

Psychosocial stress is associated with substantial morbidity and mortality. Accordingly, there is a growing interest in biomarkers that indicate whether individuals show adaptive (i.e., stress-buffering and health-promoting) or maladaptive (i.e., stress-escalating and health-impairing) stress reactions in social contexts. As heart rate variability (HRV) has been suggested to be a biomarker of adaptive behavior during social encounters, it may be possible that inter-individual differences in HRV are associated with inter-individual differences regarding stress in distinct social domains.

METHODS

To test this hypothesis, resting state HRV and psychosocial stress was assessed in 83 healthy community-dwelling individuals (age: 18-35years). HRV was derived from heart rate recordings during spontaneous and instructed breathing to assess the robustness of possible associations between inter-individual differences in HRV and inter-individual differences in psychosocial stress. Psychosocial stress was determined with a self-report questionnaire assessing stress in distinct social domains.

RESULTS

A series of categorical and dimensional analyses revealed an association between inter-individual differences in HRV and inter-individual differences in psychosocial stress: Individuals with high HRV reported less stress in social life, but not in family life, work life or everyday life, than individuals with low HRV.

CONCLUSIONS

On basis of these findings, it may be assumed that individuals with high HRV experience less psychosocial stress than individuals with low HRV. Although such an assumption needs to be corroborated by further findings, it seems to be consistent with previous findings showing that individuals with high HRV suffer less from stress and stress-related disorders than individuals with low HRV.

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and related diseases, but their precise measurement is still a challenge. Many protocols have been described for neurotransmitter measurement by a variety of instruments, including high-pressure liquid chromatography (HPLC). However, there are shortcomings, such as complicated operation or hard-to-detect multiple targets, which cannot be avoided, and presently, the dominant analysis technique is still HPLC coupled with sensitive electrochemical or fluorimetric detection, due to its high sensitivity and good selectivity. Here, a detailed protocol is described for the pretreatment and detection of catecholamines with high pressure liquid chromatography with electrochemical detection (HPLC-ECD) in real urine samples of infants, using electrospun composite nanofibers composed of polymeric crown ether with polystyrene as adsorbent, also known as the packed-fiber solid phase extraction (PFSPE) method. We show how urine samples can be easily precleaned by a nanofiber-packed solid phase column, and how the analytes in the sample can be rapidly enriched, desorbed, and detected on an ECD system. PFSPE greatly simplifies the pretreatment procedures for biological samples, allowing for decreased time, expense, and reduction of the loss of targets. Overall, this work illustrates a simple and convenient protocol for solid-phase extraction coupled to an HPLC-ECD system for simultaneous determination of three monoamine neurotransmitters (norepinephrine (NE), epinephrine (E), dopamine (DA)) and two of their metabolites (3-methoxy-4-hydroxyphenylglycol (MHPG) and 3,4-dihydroxy-phenylacetic acid (DOPAC)) in infants' urine. The established protocol was applied to assess the differences of urinary catecholamines and their metabolites between high-risk infants with perinatal brain damage and healthy controls. Comparative analysis revealed a significant difference in urinary MHPG between the two groups, indicating that the catecholamine metabolites may be an important candidate marker for early diagnosis of cases at risk for brain damage in infants.

Distinct CCL2, CCL5, CCL11, CCL27, IL-17, IL-6, BDNF serum profiles correlate to different job-stress outcomes

Chronic psychosocial stress at workplace is an important factor in the development of physical and mental illness. Objective biological measures of chronic stress are still lacking, but inflammatory response and growth factors are increasingly considered as potential stress biomarkers. Therefore, we investigated the relationship between psychophysical strain and serum levels of 48 chemokines, cytokines and growth factors measured using a multiplex immunoassay, and serum brain-derived neurotrophic factor (BDNF) measured by ELISA. Severity of psychophysical strain was scored in 115 healthy hospital workers using specific scales for anxiety, depression-like emotion, gastrointestinal or cardiac disturbances, and ergonomic dysfunction. Multivariate analysis revealed that higher anxiety scale scores were correlated with lower serum chemokine C-C motif ligand-2 (CCL2/MCP-1), chemokine C-C motif ligand-5 (CCL5/RANTES), chemokine C-C motif ligand-27 (CCL27/CTACK), chemokine C-C motif ligand-11 (CCL11/Eotaxin) and interleukin-6 (IL-6); gastrointestinal disturbances correlated with increased levels of interleukin-17 (IL-17) and reduced CCL11/Eotaxin, CCL27/CTACK and CCL2/MCP-1; while cardiac dysfunctions associate only to reduced CCL27/CTACK, and ergonomic dysfunction correlated with increased BDNF and reduced CCL11/Eotaxin and CCL5/RANTES. Thus, these 7 serum factors may provide a distinct signature for each different stress-related psychophysical outcome giving indications on individual vulnerabilities.

Evaluation of Brain Activity Using Near-infrared Spectroscopy in Inflammatory Bowel Disease Patients

Depression is implicated as a risk factor for the recurrence of inflammatory bowel disease (IBD). Near-infrared spectroscopy (NIRS) and brain-derived neurotrophic factor (BDNF) are useful tools for evaluation of brain activity and a depressive state, respectively. The aim of this study was to clarify the association between brain activity or depressive symptoms and IBD using NIRS and BDNF. This study included 36 ulcerative colitis (UC) patients, 32 Crohn’s disease (CD) patients, and 17 healthy controls (HC). Center for Epidemiologic Studies Depression Scale (CES-D) scores were determined, NIRS was performed, and serum BDNF levels were measured in all subjects. NIRS showed that the mean oxygenated hemoglobin concentration was significantly lower in the frontal lobe in the UC group than in the HC group (HC 167 ± 106 vs. UC 83.1 ± 85.3, p < 0.05). No significant difference was seen between the HC and CD groups. There were also no significant differences in CED-D scores and BDNF levels among the groups. Changes in the NIRS values of the UC group may indicate decreased brain activity and a fundamental difference between UC and CD, which are often lumped together as two types of IBD.

Serum Brain-Derived Neurotrophic Factor, and Plasma Catecholamine Metabolites in People with Major Depression: Preliminary Cross-Sectional Study

BACKGROUND

There are complicated interactions between catecholaminergic neurons and brain-derived neurotrophic factor (BDNF) in the brain. However, no reports have addressed the relationship among 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), and BDNF in the blood.

OBJECTIVE

This paper sought to investigate correlations between serum BDNF and plasma levels of MHPG and HVA in people with major depression (MD).

MATERIALS AND METHODS

A total of 148 patients (male/female 65/83, age 49.5 ± 12.1 years old) who satisfied criteria for MD based on the Diagnostic and Statistical Manual of Mental Disorders IV were enrolled in the present study. Plasma levels of MHPG and HVA were analyzed using high-performance liquid chromatography, and serum BDNF was measured using ELISA.

RESULTS

No interactions were observed between plasma HVA levels (mean ± SD = 4.5 ± 1.5 ng/mL) and age, sex, HAMD scores, or serum BDNF levels (mean ± SD = 9.8 ± 2.9 ng/mL). No correlations were not also observed between plasma MHPG levels (mean ± SD = 5.9 ± 2.1 ng/mL) and age, sex, the HAMD17 scores (mean ± SD = 22.2 ± 2.9 ng/mL), or serum BDNF levels. Serum BDNF levels were negatively associated with HAMD17 scores.

CONCLUSION

The results suggest that there are no significant correlations between catecholamine metabolites and BDNF in the blood for MDD patients.

No gene-by-environment interaction of BDNF Val66Met polymorphism and childhood maltreatment on anxiety sensitivity in a mixed race adolescent sample

Background: Anxiety disorders in youth are attributable to multiple causal mechanisms, comprising biological vulnerabilities, such as genetics and temperament, and unfavourable environmental influences, such as childhood maltreatment (CM). Objective: A gene-environment (G x E) interaction study was conducted to determine the interactive effect of the BDNF Val66Met polymorphism and CM to increase susceptibility to anxiety sensitivity (AS) in a sample of mixed race adolescents. Method: Participants (n = 308, mean age = 15.8 years) who were all secondary school students and who completed measures for AS and CM were genotyped for the BDNF Val66Met polymorphism. Hierarchical multiple regression analysis was conducted to assess G x E influences on AS. Age and gender were included in the models as covariates as age was significantly associated with AS total score (p < .05), and females had significantly higher AS scores than males (p < .05). Results: A main effect of CM on AS was evident (p < .05), however, no main effect of BDNF genotype on AS was observed (p > .05). A non-significant G x E effect on AS was revealed (p < .05). Conclusions: Our results suggest that CM does not have a moderating role in the relationship between the BDNF Val66Met genotype and the increased risk of anxiety-related phenotypes, such as AS. Given the exploratory nature of this study, findings require replication in larger samples and adjustment for population stratification to further explore the role of BDNF Val66Met and CM on AS in mixed race adolescents.

Role of tissue-type plasminogen activator and plasminogen activator inhibitor-1 in psychological stress and depression

Major depressive disorder is a common illness worldwide, but the pathogenesis of the disorder remains incompletely understood. The tissue-type plasminogen activator-plasminogen proteolytic cascade is highly expressed in the brain regions involved in mood regulation and neuroplasticity. Accumulating evidence from animal and human studies suggests that tissue-type plasminogen activator and its chief inhibitor, plasminogen activator inhibitor-1, are related to stress reaction and depression. Furthermore, the neurotrophic hypothesis of depression postulates that compromised neurotrophin brain-derived neurotrophic factor (BDNF) function is directly involved in the pathophysiology of depression. In the brain, the proteolytic cleavage of proBDNF, a BDNF precursor, to mature BDNF through plasmin represents one mechanism that can change the direction of BDNF action. We also discuss the implications of tissue-type plasminogen activator and plasminogen activator inhibitor-1 alterations as biomarkers for major depressive disorder. Using drugs that increase tissue-type plasminogen activator or decrease plasminogen activator inhibitor-1 levels may open new avenues to develop conceptually novel therapeutic strategies for depression treatment.

Burnout and cognitive impairment: Associated with serum BDNF in a Chinese Han population

BACKGROUND

Some studies have demonstrated that subjects with chronic burnout showed cognitive impairments; however, cognitive performance in burnout has been under-investigated. Increasing evidence show that brain-derived neurotrophic factor (BDNF) plays a critical role in cognitive function. We hypothesized that decreased BDNF may be associated with cognitive impairments in burnout, which has not been investigated yet. The aim of the present study was to examine the association of BDNF with cognitive impairment in burnout.

METHOD

Using a cross-sectional design, 712 healthy subjects were recruited from a general hospital and they were all measured with the Maslach Burnout Inventory (MBI). We assessed part of subjects on the repeatable battery for the assessment of neuropsychological status (RBANS) (n=192) and serum BDNF levels (n=127).

RESULTS

30.5% of the subjects had burnout. Compared to those non-burnout subjects, the burnout subjects were younger, had significant lower BDNF levels (p=0.003) and scored lower on immediate memory, RBANS total score and attention (all p<0.05). Interestingly, after the Bonferroni correction, there were negative correlations between BDNF and MBI total score or reduced professional accomplishment (PA). Moreover, BDNF was positively associated with immediate memory, attention and RBANS total score. Further multiple regression analysis showed that BDNF was an independent contributor to the RBANS total score and attention, and BDNF and MBI depersonalization (DP) were independent contributors to immediate memory. In addition, there was mediating effect of BDNF in the relation between burnout and cognitive impairments.

CONCLUSIONS

Our results suggest that burnout is associated with significant cognitive impairments and decreased BDNF. Moreover, decreased BDNF is associated with cognitive impairments in burnout.

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.

High-flavonoid intake induces cognitive improvements linked to changes in serum brain-derived neurotrophic factor: Two randomised, controlled trials

BACKGROUND: Recent clinical studies have indicated the beneficial impact of dietary flavonoid intake on human cognitive performance. Although the mechanisms that mediate such improvements are currently unclear, animal and human trial data suggest that changes in neurotrophin expression, and related signalling apparatus, may be involved.

OBJECTIVE: To investigate the link between changes in serum brain-derived neurotrophic factor (BDNF) and changes in human cognitive performance following flavonoid intake.

METHODS: The relationship between serum levels of BDNF and age, gender, BMI, waist circumference, blood pressure and cognition at baseline, and following flavonoid intake, was investigated in two distinct randomised, controlled clinical trials. Trial 1 was conducted in men and women (aged 26–70 y; consuming an average of 3 portions of fruit and vegetables per day) and delivered high-flavonoid (>15 mg/100 g) or low-flavonoid (<5 mg/100 g) fruit and vegetables and increased intake by 2 portions every 6 weeks. The control arm was habitual diet over the same time frame. Trial 2 was conducted in an older males and female cohort (aged 62–75 y) intervening with a high-flavanol cocoa drink (494 mg total flavanols) and a low-flavanol cocoa drink (23 mg total flavanols) for 12 weeks.

RESULTS: Serum BDNF levels increased linearly to the age of 65, after which BDNF levels were found to decrease markedly. All other physiological and anthropometric measurements proved to not be significantly associated with serum BDNF levels (p > 0.05), although higher levels in males compared to females almost achieved significance (p = 0.056). At baseline, higher serum BDNF levels were associated with significantly better global cognition scores, relative to individuals with lower serum levels. In addition, following intervention for 18 weeks, high-flavonoid, but not low-flavonoid, fruit and vegetable intake induced significant improvements in cognitive performance and increases in serum BDNF levels (p = <0.001). Flavanol intervention for 12 weeks also resulted in significant increases in serum BDNF (p = <0.001), and such increases were correlated with improvements in global cognitive performance.

CONCLUSION: Increases in global cognition induced by high flavonoid fruit and vegetables, and cocoa flavanols were paralleled by concurrent changes in serum BDNF levels, suggesting a role for BDNF in flavonoid-induced cognitive improvements. Furthermore, we provide further data suggesting that serum BDNF levels may represent a biomarker of cognitive function.

COMT haplotypes, catecholamine metabolites in plasma and clinical response in schizophrenic and bipolar patients

Aim: We examined the association of COMT haplotypes and plasma metabolites of catecholamines in relation to the clinical response to antipsychotics in schizophrenic and bipolar patients. Patients & methods: We studied 165 patients before and after four weeks of treatment, and 163 healthy controls. We assessed four COMT haplotypes and the plasma concentrations of HVA, DOPAC and MHPG. Results: Bipolar patients: haplotypes are associated with age at onset and clinical evolution. In schizophrenic patients, an haplotype previously associated with increased risk, is related to better response of negative symptoms. Conclusion: Haplotypes would be good indicators of the clinical status and the treatment response in bipolar and schizophrenic patients. Larger studies are required to elucidate the clinical usefulness of these findings.

Brain-derived neurotrophic factor serum levels in heroin-dependent patients after 26weeks of withdrawal

BACKGROUND

Brain-derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of heroin dependence. BDNF expression is dramatically changed during drug withdrawal, and is associated with drug withdrawal syndrome. This study aimed to explore (1) alterations of BDNF serum levels in heroin-dependent patients after long term abstinence; and (2) the association between BDNF serum levels and protracted withdrawal syndrome.

METHOD

Fifty-three male heroin-dependent patients and fifty-two gender-matched healthy controls were enrolled in this study. We measured BDNF serum levels at baseline and 26 weeks after heroin abstinence. Moreover, protracted withdrawal symptoms, depression and anxiety symptoms were measured by Protracted Withdrawal Symptoms of Heroin-dependent patients (PWSHA), Self-rating Depression Scale (SDS) and Self-rating Anxiety Scale (SAS), respectively.

RESULT

We found that baseline BDNF serum levels were significantly lower in heroin-dependent patients compared to controls (p<0.01). There was also a significantly difference in BDNF serum levels among heroin-dependent patients at baseline and 26-week follow-up (p<0.01). The BDNF serum levels were not associated with age, BMI, years of education, age of initial use, or duration of use. Of the clinical symptoms measured, the change in BDNF serum levels from baseline to 26-week follow-up was negatively associated with the change in PWSHA scores (r = -0.44, p<0.01, see Table 2 and Figure 2 for details).

CONCLUSION

The results show that the BDNF serum levels in heroin-dependent patients are lower than those of healthy controls at baseline and increased after 26 weeks of abstinence, although the BDNF serum levels are still lower than those of the healthy controls. A negative correlation between the change in BDNF serum levels and protracted withdrawal symptoms was found but needs to be confirmed in further study. The results revealed that BDNF serum level is worth paying attention to in order to further investigate the possibility of it being a biomarker of treatment outcome for opiate dependence.

Serum brain-derived neurotrophic factor levels and psychotic symptoms in heroin dependence

OBJECTIVES

Psychotic symptoms are commonly observed among heroin users. Low serum brain-derived neurotrophic factor (BDNF) levels have been reported in schizophrenia and psychosis; however, studies assessing the relationship between serum BDNF levels and psychotic symptoms in heroin dependence are lacking.

METHOD

A total of 31 heroin-dependent patients who had never experienced psychotic symptoms during heroin consumption and 21 patients with a history of psychotic symptoms were consecutively recruited. We measured by enzyme-linked immunosorbent assay (ELISA) serum BDNF levels during early abstinence. A gender- and age-matched sample of healthy controls was also recruited and underwent measurement of BDNF.

RESULTS

BDNF levels were significantly lower in patients with psychotic symptoms than in those without psychotic symptoms (P<0.001). BDNF levels were not found to be correlated with sex, age, age of onset, duration of heroin use, average daily dose of heroin use, frequency of heroin use, SDS scores, BAI scores and BDI scores in the psychotic subsamples (all P>0.05).

CONCLUSIONS

Our findings suggest that heroin-dependent patients with psychotic symptoms share some of the neurotrophic insult that characterizes schizophrenia and psychosis.

Changes in brain-derived neurotrophic factor (BDNF) during abstinence could be associated with relapse in cocaine-dependent patients

Brain-derived neurotrophic factor (BDNF) is involved in cocaine craving in humans and drug seeking in rodents. Based on this, the aim of this study was to explore the possible role of serum BDNF in cocaine relapse in abstinent addicts. Forty cocaine dependent subjects (DSM-IV criteria) were included in an inpatient 2 weeks abstinence program. Organic and psychiatric co-morbidities were excluded. Two serum samples were collected for each subject at baseline and at after 14 abstinence days. After discharge, all cocaine addicts underwent a 22 weeks follow-up, after which they were classified into early relapsers (ER) (resumed during the first 14 days after discharge,) or late relapsers (LR) (resumed beyond 14 days after discharge). The only clinical differences between groups were the number of consumption days during the last month before detoxification. Serum BDNF levels increased significantly across the 12 days of abstinence in the LR group (p=0.02), whereas in the ER group BDNF remained unchanged. In the ER group, the change of serum BDNF during abstinence negatively correlated with the improvement in depressive symptoms (p=0.02). These results suggest that BDNF has a role in relapse to cocaine consumption in abstinent addicts, although the underlying neurobiological mechanisms remain to be clarified.

Preanalysis storage conditions influence the measurement of brain-derived neurotrophic factor levels in peripheral blood

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that plays a pivotal role in regulating neuronal function throughout life, and this factor is regarded as a potential biomarker of mental disorders. However, previous studies have suggested that plasma BDNF levels are more variable than serum BDNF levels.

METHODS

We determined the influence of time and temperature on the measurement of peripheral blood BDNF levels. Blood samples were aliquoted into four types of tubes, including tubes containing heparin, ethylenediaminetetraacetic acid (EDTA), and citrate for plasma, and anticoagulant-free tubes for serum. The samples were stored at 4 or 25°C for 0, 1, 2, 4, 6, 24 or 48 h, and the plasma and serum BDNF levels were measured using enzyme-linked immunosorbent assay.

RESULTS

There were interindividual and interanticoagulant compound variability in the plasma BDNF levels. The measured plasma BDNF levels increased over time, whereas the serum BDNF levels remained unchanged. Furthermore, the BDNF levels detected in plasma stored in heparin tubes at 4°C and those for samples stored in EDTA tubes at 25°C were much higher than those of the other samples.

CONCLUSION

This study indicates that measurements of plasma BDNF levels are dependent not only on the anticoagulant compounds but also on the storage time and temperature conditions used after blood sampling.

Change in well-being amongst participants in a four-month pedometer-based workplace health program

BACKGROUND

There is increasing uptake of workplace physical activity programs to prevent chronic disease. While they are frequently evaluated for improvement in biomedical risk factors there has been little evaluation of additional benefits for psychosocial health. We aimed to evaluate whether participation in a four-month, team-based, pedometer-based workplace health program known to improve biomedical risk factors is associated with an improvement in well-being, immediately after the program and eight-months after program completion.

METHODS

At baseline (2008), 762 adults (aged 40 ± 10 SD years, 42% male) employed in primarily sedentary occupations and voluntarily enrolled in a physical activity program were recruited from ten Australian worksites. Data was collected at baseline, at the completion of the four-month program and eight-months after program completion. The outcome was the WHO-Five Well-being Index (WHO-5), a self-administered five-item scale that can be dichotomised as 'poor' (less than 52%) or 'positive' (more than or equal to 52%) well-being.

RESULTS

At baseline, 75% of participants had positive well-being (mean: 60 ± 19 SD WHO-5 units). On average, well-being improved immediately after the health program (+3.5 units, p < 0.001) and was sustained eight-months later (+3.4 units from baseline, p < 0.001). In the 25% with poor well-being at baseline, 49.5% moved into the positive well-being category immediately after program completion, sustained eight-months later (p < 0.001).

CONCLUSIONS

Clinically relevant immediate and sustained improvements in well-being were observed after participation in the health program. These results suggest that participation in workplace programs, such as the one evaluated here, also has the potential to improve well-being.

Decreased plasma brain-derived neurotrophic factor and vascular endothelial growth factor concentrations during military training

Decreased concentrations of plasma brain-derived neurotrophic factor (BDNF) and serum BDNF have been proposed to be a state marker of depression and a biological indicator of loaded psychosocial stress. Stress evaluations of participants in military mission are critically important and appropriate objective biological parameters that evaluate stress are needed. In military circumstances, there are several problems to adopt plasma BDNF concentration as a stress biomarker. First, in addition to psychosocial stress, military missions inevitably involve physical exercise that increases plasma BDNF concentrations. Second, most participants in the mission do not have adequate quality or quantity of sleep, and sleep deprivation has also been reported to increase plasma BDNF concentration. We evaluated plasma BDNF concentrations in 52 participants on a 9-week military mission. The present study revealed that plasma BDNF concentration significantly decreased despite elevated serum enzymes that escaped from muscle and decreased quantity and quality of sleep, as detected by a wearable watch-type sensor. In addition, we observed a significant decrease in plasma vascular endothelial growth factor (VEGF) during the mission. VEGF is also neurotrophic and its expression in the brain has been reported to be up-regulated by antidepressive treatments and down-regulated by stress. This is the first report of decreased plasma VEGF concentrations by stress. We conclude that decreased plasma concentrations of neurotrophins can be candidates for mental stress indicators in actual stressful environments that include physical exercise and limited sleep.

Exploration of the burnout syndrome occurrence among mental health nurses in Cyprus

Nurses' work-related stress might be associated with psychiatric symptoms, leading to altered professional attitudes. The aim of this study was to explore the levels of burnout and associations with anxiety and depressive symptoms among Greek-Cypriot psychiatric-mental health nurses (PMHNs). A descriptive correlational design with cross-sectional comparisons was applied. A sample of 226 PMHNs was used. Participants reported low levels of burnout. However, 10% of them manifested clinically significant anxiety and depressive symptoms. Emotional exhaustion and depersonalization were associated with depressive (r=0.562, p<0.0001, and r=0.616, p<0.0001, respectively) and anxiety (r=0.394, p<0.0001, and r=0.448, p<0.0001, respectively) symptoms. Further research investigating the biological aetiopathology of these psychological alterations is warranted.

Plasma levels of interleukin-6 and selective serotonin reuptake inhibitor response in patients with major depressive disorder

OBJECTIVE

We investigated the plasma levels of interleukin (IL)-6 and 5-HTT polymorphisms in patients with major depressive disorder (MDD). This is the first report, to our knowledge, of an investigation into the association between 5-HTT gene polymorphism, plasma IL-6 levels, and responses to selective serotonin reuptake inhibitors (SSRIs) in Japanese patients with MDD.

METHOD

One-hundred and eighteen patients (51 male, 67 female) who met the DSM-IV criteria for MDD were enrolled. Their ages ranged from 24 to 78 (mean ± SD = 44 ± 12) years. The patients were treated with SSRIs (paroxetine in 66 cases, sertraline in 42 cases) for 8 weeks.

RESULTS

The plasma levels of IL-6 were significantly higher in the SSRI responders than in the nonresponders (p = 0.0328), and the changes in plasma IL-6 levels correlated significantly with the changes in severity of depressive state (p = .0.007). No difference was found in baseline and the changes in plasma IL-6 levels between the patients with a 5-HTT gene (5-HTTLPR) L-carrier and those with S/S.

CONCLUSION

These results suggest that the plasma levels of IL-6 reflect the severity of MDD and that plasma IL-6 levels might be another biological-state marker for the depressive state. In addition, the 5-HTTLPR polymorphism might be independent of plasma IL-6 levels.

Interplay between pro-inflammatory cytokines and growth factors in depressive illnesses

The development of depressive disorders had long been attributed to monoamine variations, and pharmacological treatment strategies likewise focused on methods of altering monoamine availability. However, the limited success achieved by treatments that altered these processes spurred the search for alternative mechanisms and treatments. Here we provide a brief overview concerning a possible role for pro-inflammatory cytokines and growth factors in major depression, as well as the possibility of targeting these factors in treating this disorder. The data suggest that focusing on one or another cytokine or growth factor might be counterproductive, especially as these factors may act sequentially or in parallel in affecting depressive disorders. It is also suggested that cytokines and growth factors might be useful biomarkers for individualized treatments of depressive illnesses.

Sensitive profiling of biogenic amines in human urine by capillary electrophoresis with field amplified sample injection

In order to monitor biogenic amines in human urine, a method based on field-amplified sample injection combined with capillary electrophoresis and direct UV absorption detection was developed. Dopamine, tyramine, tryptamine, serotonin and epinephrine were effectively separated and identified in human urine samples, and detection limits were 0.072, 0.010, 0.027, 0.010 and 0.120 µmol/L, respectively. Detection limits comparable to laser-induced fluorescence detection or solid phase extraction combined with capillary electrophoresis were achieved. Parameters affecting electrophoretic system detection sensitivity were investigated. Optimal separation conditions were obtained using as background electrolyte a pH 6.5 mixture of 2-(morpholino)ethanesulfonic acid 20 mmol/L and 30 mmol/L phosphate buffer, containing 0.05% hydroxypropylcellulose and 10% v/v methanol. Injections of the sample solution were performed by applying a voltage of 12 kV for 50 s. Recovery and accuracy ranged between 89.4 and 94.9%, and 89 and 112%, respectively. The method was successfully applied on actual urine samples (from a healthy volunteer): target bioamine content was consistent with endogenous levels reported in the literature. The proposed method is simple, fast and inexpensive and can be conveniently employed in work-related stress studies. The affordability and noninvasive sampling of the method allow epidemiological studies on large number of exposed persons to be performed.

The effects of a walking intervention on depressive feelings and social adaptation in healthy workers

The effects of walking on mental health problems among healthy Japanese workers are not fully understood. In the present study, we investigated the effects of a four-week walking program on the psychological functioning of a nonclinical sample of healthy workers in Japan.A total of 606 healthy subjects were enrolled in the study and were evaluated by the Zung Self-rating Depression Scale (SDS) and the Social Adaptation Self-evaluation Scale (SASS) both before and after the walking program.The subjects were divided into an exercising group and a non-exercising group.There were significant differences in the SDS and SASS scores between the exercising and the non-exercising groups.Following the walking program, the non-exercising group's SDS scores decreased and their SASS scores increased compared to before the walking program.In contrast, the SDS and SASS scores of the exercising group did not change.These results suggest that subjects who exercise regularly experience fewer depressive feelings and exhibit better social adaptation in the workplace than those who do not exercise.The walking program improved depressive feelings and social adaptation in the non-exercising group.

[The development of depression: the role of brain-derived neurotrophic factor]

An association between the presence of psychosocial stress, its pathological processing and the development of depression is well documented. This review reports and discusses studies suggesting a reduced release of brain-derived neurotrophic factor (BDNF) under stress as a possible mechanism. The studies show a reduction of BDNF secretion in stressful situations, a decreased blood concentration in depression and a normalization of BDNF by successful antidepressant therapy. As a possible mechanism of BDNF action, a reactivation of neuroplasticity is being discussed, especially in hippocampal and cortical networks. On the other hand, methodological limitations, such as the impossibility of determining the cerebral BDNF concentration in vivo and ruling out a variety of possible confounders, may restrict the significance of the studies. The question of whether the ascertained changes of BDNF levels are causally involved in the pathophysiology of depression or whether they are just an epiphenomenal result of depression-induced stress is still under debate.

The effects of hazardous chemical exposure on cardiovascular disease in chemical products manufacturing workers

The purpose of this study was to understand the mechanism of cardiovascular disease (CVD) caused by exposure to hazardous chemicals. We investigated changes in the symptoms of metabolic syndrome, which is strongly related to CVD, and in levels of other CVD risk factors, with a special emphasis on the roles of catecholamines and oxidative stress. The results revealed that neither body mass index (BMI) nor waist and hip circumferences were associated with exposure to hazardous chemicals. Among metabolic syndrome criteria, only HDL-cholesterol level increased on exposure to hazardous chemicals. Levels of epinephrine (EP) and norepinephrine (NEP) were not influenced by exposure to hazardous chemicals; however, the total antioxidative capacity (TAC) reduced because of increased oxidative stress. Both hazardous chemical exposure level and metabolite excretion were related to EP, NEP, and the oxidative stress index (OSI). Logistic regression analysis with these factors as independent variables and metabolic syndrome criteria as dependent variables revealed that EP was associated with blood pressure, and NEP with metabolic syndrome in the chemicalexposed group. In conclusion, the results suggest that reactive oxygen species generated and oxidative stress due to exposure to hazardous chemicals act as mediators and cause changes in the physiological levels of EP and NEP to increase blood pressure. This ultimately leads to the development of CVD through increase in cholesterol, triglyceride, and blood glucose levels by lipid peroxidation.

Defensive coping and subclinical vascular disease risk - associations with autonomic exhaustion in Africans and Caucasians: the SABPA study

OBJECTIVE

The defensive active coping response is a recognised cardiovascular risk factor in Africans, especially in men. It is uncertain whether autonomic dysfunction might be the underlying cause. We therefore investigated associations between salivary MHPG (3-methoxy-4-hydroxyphenolglycol), as a marker of sympathetic activity, and subclinical vascular disease risk in defensive coping Africans and Caucasians.

METHODS

The Coping Strategy Indicator questionnaire identified participants who preferably utilise defensive coping. Ambulatory blood pressure was monitored for 24 h and carotid intima-media thickness (CIMT) was determined from ultrasound images, as an indicator of subclinical vascular disease risk. Salivary MHPG was analysed with high performance liquid chromatography.

RESULTS

Defensive active coping Africans (n = 143) showed overall poorer health than Caucasians (n = 148), with higher self-reported stress, alcohol abuse, hypertension, abdominal obesity, and risk of diabetes (p ≤ 0.05). African women demonstrated lower levels of MHPG compared with Caucasian women, although no differences in men were found. Furthermore, Africans revealed a trend of increased low grade inflammation and glycated haemoglobin which was associated with increased CIMT. There was an inverse association between MHPG and CIMT [β = -0.22 (-0.40, -0.03)], in African men with a high risk of subclinical vascular disease (n = 30).

CONCLUSIONS

Novel findings revealed that defensive active coping Africans are more at risk of subclinical vascular disease, possibly resultant of autonomic exhaustion (decreased MHPG). When defensive coping fails, sympathetic hyperactivity may be followed by autonomic exhaustion and sympatho-adrenal-medullary system desensitisation, resulting in pathology.

Differential effects of diazepam, tandospirone, and paroxetine on plasma brain-derived neurotrophic factor level under mental stress

OBJECTIVES

Serum brain-derived neurotrophic factor (BDNF) levels are reduced in depressed patients, and successful antidepressant treatment leads to increases in BDNF levels. However, little is known about how psychotropic drugs affect the mechanism of the human response to mental stress. We investigated the influence of psychotropic drugs on plasma BDNF levels under mental stress using a driving simulator (DS) task.

METHODS

Fourteen healthy male volunteers received one of four drugs, diazepam (5 mg), tandospirone (20 mg), paroxetine (10 mg), and matched placebo, in a double-blind, crossover manner. Subjects were asked to perform the DS task 4 h post-dosing. Plasma BDNF levels were measured before and after the DS task.

RESULTS

Plasma BDNF levels under the placebo, diazepam, and tandospirone conditions significantly decreased after the DS task compared with before the task. Conversely, no significant differences in plasma BDNF levels were detected under the paroxetine condition.

CONCLUSION

As these three psychotropic drugs have differential effects on plasma BDNF levels under mental stress after 4 h post-dosing, antidepressants, unlike anxiolytics, might have a prompt positive effect on the mental stress response.

BDNF function as a potential mediator of bipolar disorder and post-traumatic stress disorder comorbidity

Bipolar disorder (BD) and post-traumatic stress disorder (PTSD) frequently co-occur among psychiatric patients, leading to increased morbidity and mortality. Brain-derived neurotrophic factor (BDNF) function is associated with core characteristics of both BD and PTSD. We propose a neurobiological model that underscores the role of reduced BDNF function resulting from several contributing sources, including the met variant of the BDNF val66met (rs6265) single-nucleotide polymorphism, trauma-induced epigenetic regulation and current stress, as a contributor to the onset of both illnesses within the same person. Further studies are needed to evaluate the genetic association between the val66met allele and the BD-PTSD population, along with central/peripheral BDNF levels and epigenetic patterns of BDNF gene regulation within these patients.

Postpartum depressive symptoms and the BDNF Val66Met functional polymorphism: effect of season of delivery

Postpartum depression (PPD) is an often underdiagnosed and undertreated mood disorder, with negative impact on the mother's and infant's health. Seasonal variation has been discussed as a risk factor for PPD. Candidate genes, such as those encoding for the brain-derived neurotrophic factor (BDNF), serotonin transporter (5-HTT), and Period2 (PER2), have been associated with depression and seasonal disorders. The present study is aimed to examine whether functional polymorphic variants, BDNF Val66Met, 5-HTTLPR, or PER2 SNP 10870, are associated with PPD symptoms and whether these genetic polymorphisms interact with season in predicting PPD symptoms. This case-control study comprised of 275 women from a population-based cohort of delivering women in Sweden, who completed a questionnaire containing the Edinburgh postnatal depression scale (EPDS) at 6 weeks and 6 months postpartum. Stressful life events (SLEs) and maternity stressors were also assessed. The results did not reveal any statistically significant overall association between the studied genetic polymorphisms and PPD symptoms. However, a significant association between BDNF Met66 carrier status and development of PPD symptoms at 6 weeks postpartum, even when controlling for prepartum and postpartum environmental risk factors, was evident among mothers delivering during autumn/winter. No gene-gene interactions were found but a cumulative effect was detected with carriers of a greater number of 5-HTTLPR S and BDNFVal66Met Met alleles reporting higher EPDS scores, if delivered during autumn/winter. Our findings propose a role of the BDNF gene in the development of PPD symptoms, potentially mediated by season of delivery.

Developing biomarkers for methamphetamine addiction

There are an estimated 11.7 million methamphetamine (MA) abusers in the United States and epidemics of MA addiction are occurring worldwide. In our human laboratory and outpatient clinical trials we use innovative methods to quantify the severity of MA addiction and test biomarkers that may predict response to therapy or risk of relapse. One potential biomarker of addiction is the quantity of abused drug intake. Qualitative urinalysis is used in clinical trials and during treatment but provides only a binary outcome measure of abuse. Using non-pharmacologic doses of deuterium labeled l-MA we have developed a continuous quantitative measure to estimate the bioavailable amount of MA addicts ingest. Brain Derived Neurotrophic Factor is a neurotrophin that encourages growth and differentiation of new neurons and synapses. Low BDNF levels are seen in many addictive disorders and BDNF is elevated in recovering MA addicts, suggesting BDNF may be a marker of MA addiction. We are investigating the effects of controlled doses of MA on BDNF levels and gene regulation and measuring BDNF in our clinical trials. We believe both patients and clinical researches will benefit from the addition of new, objective and quantifiable outcome measures that reflect disease severity and recovery from addiction.

Brain-derived neurotrophic factor (BDNF) plasma levels in drug-naïve OCD patients are lower than those in healthy people, but are not lower than those in drug-treated OCD patients

BACKGROUND

Brain-derived neurotrophic factor (BDNF) plays an important role in neural development, and has been implicated in the development of depressive and anxiety disorders. Obsessive-compulsive disorder (OCD) is a chronic anxiety disorder with an unclear pathophysiology. Although genetic studies have suggested an association between BDNF and OCD, the results have been inconsistent. The aims of this study were to determine whether BDNF plasma levels in OCD patients are lower than those in healthy controls and whether BDNF plasma levels differ between drug-naïve and drug-treated OCD patients.

METHODS

We examined BDNF plasma levels in 22 drug-naïve OCD patients, 52 drug-treated OCD patients, and 63 healthy controls. Individuals in all groups with a current or lifetime history of depression were excluded.

RESULTS

BDNF plasma levels in both drug-naïve OCD patients (1.97 ± 1.80 ng/ml, p=0.00) and drug-treated OCD patients (1.98 ± 1.54 ng/ml, p=0.00) were lower than those in normal controls (4.09 ± 2.00 ng/ml). However BDNF plasma levels in those two OCD patients groups were not different from each other significantly (p=0.99). Length of drug treatment was positively associated with BDNF plasma levels in the drug-treated patients (r=0.34, p=0.03).

LIMITATIONS

We used treatment length of two weeks and above as the criterion to recruit drug-treated patients. Probably this treatment length is not sufficient to identify drug-associated changes in BDNF levels.

CONCLUSIONS

Our findings support the hypothesis that BDNF is involved in the pathophysiology of OCD, and may be a peripheral marker indicating neurotrophic impairment in OCD.

Serum BDNF levels before treatment predict SSRI response in depression

OBJECTIVES

The "neurotrophin hypothesis" of depression posits a role of brain-derived neurotrophic factor (BDNF) in depression, although it is unknown whether BDNF is more involved in the etiology of depression or in the mechanism of action of antidepressants. It is also unknown whether pre-treatment serum BDNF levels predict antidepressant response.

METHODS

Thirty un-medicated depressed subjects were treated with escitalopram (N=16) or sertraline (N=14) for 8 weeks. Twenty-five of the depressed subjects completed 8 weeks of antidepressant treatment and had analyzable data. Twenty-eight healthy controls were also studied. Serum for BDNF assay was obtained at baseline in all subjects and after 8 weeks of treatment in the depressed subjects. Depression ratings were obtained at baseline and after 8 weeks of treatment in the depressed subjects.

RESULTS

Pre-treatment BDNF levels were lower in the depressed subjects than the controls (p=0.001) but were not significantly correlated with pre-treatment depression severity. Depression ratings improved with SSRI treatment (p<0.001), and BDNF levels increased with treatment (p=0.005). Changes in BDNF levels were not significantly correlated with changes in depression ratings. However, pre-treatment BDNF levels were directly correlated with antidepressant responses (p<0.01), and "Responders" to treatment (≥ 50% improvement in depression ratings) had higher pre-treatment BDNF levels than did "Non-responders" (p<0.05).

CONCLUSIONS

These results confirm low serum BDNF levels in un-medicated depressed subjects and confirm antidepressant-induced increases in BDNF levels, but they suggest that antidepressants do not work simply by correcting BDNF insufficiency. Rather, these findings are consistent with a permissive or facilitatory role of BDNF in the mechanism of action of antidepressants.

Brain-derived neurotrophic factor in patients with Huntington's disease

Reduced Brain-Derived Neurotrophic Factor (BDNF) levels have been described in a number of patho-physiological conditions, most notably, in Huntington's disease (HD), a progressive neurodegenerative disorder. Since BDNF is also produced in blood, we have undertaken the measurement of its peripheral levels in the attempt to identify a possible link with HD prognosis and/or its progression. Here we evaluated BDNF level in 398 blood samples including 138 controls, 56 preHD, and 204 HD subjects. We found that BDNF protein levels were not reliably different between groups, whether measured in plasma (52 controls, 26 preHD, 105 HD) or serum (39 controls, 5 preHD, 29 HD). Our experience, and a re-analysis of the literature highlighted that intra-group variability and methodological aspects affect this measurement, especially in serum. We also assessed BDNF mRNA levels in blood samples from 47 controls, 25 preHD, and 70 HD subjects, and found no differences among the groups. We concluded that levels of BDNF in human blood were not informative (mRNA levels or plasma protein level) nor reliable (serum protein levels) as HD biomarkers. We also wish to warn the scientific community in interpreting the significance of changes measured in BDNF protein levels in serum from patients suffering from different conditions.

BDNF serum levels, but not BDNF Val66Met genotype, are correlated with personality traits in healthy subjects

Consisting evidence in animal models has suggested that alterations in brain-derived neurotrophic factor (BDNF) brain expression and release are involved in the pathogenesis of mental illnesses, such as, mood, anxiety, and eating disorders. This hypothesis is supported by data emerging from biochemical studies on serum BDNF levels and genetic studies on the functional polymorphism Val66Met in the BDNF gene in patients and control subjects. Anxiety-related personality traits are associated with several mental disorders. However, they are also measurable in non-affected subjects and, so, may represent a useful "endophenotype" to study the biological correlation of the vulnerability factors in the general population. In this study, we analyzed putative correlations in subjects unaffected by mental disorders between personality traits, serum BDNF levels (N = 107), and the BDNF Val66Met genotype (N = 217). Furthermore, we tested the possible interactions between these variables. A significant correlation has been observed between high scores of harm avoidance (HA) measured by the temperament and character inventory (TCI), and low BDNF serum concentration (r = -0.253, P = 0.009). In addition, an association has been evidenced between low BDNF levels in serum and the BDNF Val/Val genotype (P = 0.021). By analyzing putative concomitant effects of different variables on HA scores in a regression model, we observed a significant correlation only with BDNF serum concentrations (P = 0.022). The study results suggest that a decrease in serum BDNF concentrations may represent a biochemical marker associated with anxiety personality traits also retrievable in the general population.