Carolina Bianchi

Brain-derived neurotrophic factor plasma levels in patients suffering from post-traumatic stress disorder

In both animals and humans, stress has been demonstrated to reduce the expression of the Brain-Derived Neurotrophic Factor (BDNF), a neurotrophin (NT) which promotes the proliferation, survival and differentiation of neurons. Although traumatic events have been found to be associated with lower BDNF plasma levels in affective disorders, no study has explored this parameter in patients with post-traumatic stress disorder (PTSD). We, therefore, measured BDNF plasma level in 18 patients with PTSD and in 18 healthy control subjects. Diagnoses were assessed by the Structured Clinical Interview for DSM-IV, while the specific symptoms were examined in the patients by means of the Impact of Event Scale for PTSD and the traumas experienced were assessed by using the Life Events Checklist. BDNF plasma levels were evaluated by means of a standardized Elisa method. The results, while showing significantly lower BDNF levels in PTSD patients, as compared with those of healthy subjects (p=0.001), although obtained in a small sample size, would suggest that this NT may be involved in the pathophysiology of PTSD.

Plasma Brain-Derived Neurotrophic Factor in treatment-resistant depressed patients receiving electroconvulsive therapy

There is an increasing evidence that the Brain-Derived Neurotrophic Factor (BDNF) could be involved in the mode of action of antidepressants and, perhaps, of ECT. This study aimed to investigate whether the clinical course of medication-resistant depressed patients following a course of ECT might be associated with changes of plasma BDNF concentrations. Our findings showed that at T0 (baseline) plasma BDNF levels of patients were significantly lower than those of control subjects, and that at T2 (after ECT) were significantly increased in parallel with the decrease of the Hamilton Rating Scale for Depression (HRSD) total score. However, only remitter patients who showed higher baseline BDNF levels than non-remitters reached normalized BDNF levels after ECT. These findings would suggest the potential usefulness of baseline plasma BDNF levels as predictors of response to ECT in treatment-resistant depressed patients.

DIURNAL VARIATION OF PLASMA BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IN HUMANS: AN ANALYSIS OF SEX DIFFERENCES

Scant information is available on the diurnal variation of peripheral neurotrophic factors, including brain‐derived neurotrophic factor (BDNF), in human beings. We explored plasma and serum BDNF levels at three different clock times in a study of 28 healthy subjects of both sexes. Statistically significant diurnal variation in plasma BDNF level was detected in men, with the peak at 08:00 h and nadir at 22:00 h. At this time, the plasma BDNF concentration of men was significantly lower than that of women (p=.02). However, no diurnal variation was found either in plasma BDNF of women, in either the follicular or luteal phases of the menstrual cycle, or in serum BDNF level in both men and women. These findings support the concept of rhythmic variation in plasma BDNF regulation that seems to be sex‐related. (Author correspondence: dmarazzi@psico.med.unipi.it)

Associations between Brain-Derived Neurotrophic Factor Plasma Levels and Severity of the Illness, Recurrence and Symptoms in Depressed Patients

Background: There is increasing evidence that the brain-derived neurotrophic factor (BDNF) is involved in the pathophysiology of mood disorders and that its peripheral levels represent a reliable mirror of its concentration in the brain. The aim of the present study was to measure BDNF plasma levels in patients affected by major depression and to explore the possible relationship between the biological parameter and characteristics of the illness. Method: BDNF plasma levels were evaluated in 30 inpatients suffering from major depression, according to DSM-IV criteria, by means of a commonly employed ELISA method. The clinical characteristics were assessed by the Hamilton Rating Scale for Depression (HRSD) and the Clinical Global Impression Scale. Results: BDNF plasma levels were significantly lower in the patients with the severest illness compared with the others, and the same was true for patients with dissociative symptoms, severe sleep disturbance and recurrent depression. A significant and negative correlation was observed between the biological parameter and the retardation factor score of the HRSD. Conclusion: These findings suggest that low BDNF levels are related to both recurrence and severity of depression, as well as to symptoms typical of dysfunctions of the hypothalamic-pituitary-adrenal axis.

Brain-derived neurotrophic factor in romantic attachment

Social attachment is fundamental for its relevant impact upon survival and reproduction in several animals and particularly so in humans. Recently, much research efforts have been directed towards the understanding of the neurobiological basis of social attachment. Besides oxytocin, vasopressin and specific brain areas, it has also been suggested that neurotrophins (NTs) might be involved. NTs are a family of structurally similar proteins including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) amongst others, which play an important role in the survival, differentiation and functioning of neurons (Patapoutian & Reichardt, 2001). Preclinical studies suggest that BDNF might be involved in hippocampal degeneration (Duman et al. 1997) following different stressors, such as maternal deprivation (Meaney, 2001). The BDNF changes would render adult animals more vulnerable to exaggerated stress responses and anxious behaviours (Ladd et al. 2004). These findings suggest that BDNF, and perhaps all NTs, might act as mediators to translate the effects of environmental stimuli on the development of the ‘social brain’. A type of social attachment that seems to be peculiar to humans is the so-called ‘romantic attachment ’, which is the establishment of a relationship between two sexual partners (Hazan & Shaver, 1987). Given the lack of information on this topic, we explored the possible relationship between BDNF plasma levels and romantic attachment, as assessed by the Experiences in Close Relationships (ECR) questionnaire (Brennan et al. 1998), a self-report instrument for measuring romantic attachment in adults.

Contents Vol. 62, 2010

A. Drago, Naples G. Erdmann, Berlin A. Fischer, Göttingen J.M. Ford, San Francisco, Calif. S. Galderisi, Naples M. Hatzinger, Solothurn U. Hegerl, Leipzig K. Hirata, Mibu M. Kato, Osaka J. Kornhuber, Erlangen D. Lehmann, Zürich P. Monteleone, Naples G. Okugawa, Osaka G.N. Papadimitriou, Athens M. Popoli, Milano M. Reuter, Bonn F. Rösler, Marburg G. Ruigt, Oss J.K. Rybakowski, Poznan F. Schneider, Aachen R. Schwarting, Marburg M. Shigeta, Tokyo D. Souery, Brussels A. Steiger, Munich P. Willner, Swansea Associate Editors