Electroconvulsive Therapy (ECT) increases serum Brain Derived Neurotrophic Factor (BDNF) in drug resistant depressed patients

Vascular Endothelial Growth Factor (VEGF) serum concentration during electroconvulsive therapy (ECT) in treatment resistant depressed patients

Vascular endothelial growth factor (VEGF) is an angiogenic cytokine, which induces vasopermeability and facilitates neurogenesis and synaptic plasticity in the adult brain. Expression studies in animal models have reported that brain VEGF is regulated by electroconvulsive seizures (ECS), which are used in an experimental paradigm similar to clinical electroconvulsive therapy (ECT) a treatment for drug resistant depressed (TRD) patients. The aim of this study was to investigate putative modulations of ECT on VEGF serum levels in TRD patients. Nineteen patients were enrolled in the study; illness severity and VEGF serum contents were assessed before the treatment (T0), the day after the end of ECT (T1) and one month later the end of ECT (T2). ECT treatment improved depression symptomatology as measured by MADRS scores (p<0.0001). No changes occurred in serum VEGF between T0 and T1, whereas a significant increase was observed between T0 and T2 (p=0.042). Moreover a significant correlation was observed between the VEGF increase at T2 and the reduction in MADRS scores (p=0.049). This study is the first to evaluate putative modulations of serum VEGF induced by ECT in TRD patients.

Brain-derived neurotrophic factor and electroconvulsive therapy in a schizophrenic patient with treatment-resistant paranoid-hallucinatory symptoms

It has been proposed that deficits in the production and the utilization of brain-derived neurotrophic factor (BDNF) may contribute to the pathogenesis of schizophrenia. At the same time, electroconvulsive shock, an experimental model of electroconvulsive therapy (ECT), has been shown to induce an increase of BDNF protein in brains of animal models. These findings suggest that one putative mechanism of action of ECT is the regulation of BDNF and/or related neurotrophins. In this case report, a 54-year-old man with severe treatment-resistant schizophrenic symptoms was treated with ECT. To evaluate the effect of ECT on BDNF serum levels, we collected a blood sample before each ECT session. During the course of ECT treatment, the paranoid and hallucinatory symptoms gradually improved, whereas BDNF levels increased over time. In addition, there was a general improvement of its positive and negative schizophrenic symptoms and depressive state. In conclusion, this case report further validates the therapeutic efficacy of ECT in schizophrenic patients with inadequate or poor response to traditional treatments. Moreover, ECT therapeutic effect is associated with an increase in BDNF serum levels. Further studies are needed to characterize the relationship between BDNF and ECT in schizophrenic patients.

Depressive symptoms following interferon-α therapy: mediated by immune-induced reductions in brain-derived neurotrophic factor?

Interferon-α (IFN-α) therapy for the treatment of hepatitis C is known to induce depressive symptoms and major depression in a substantial proportion of patients. While immune activation and disturbances in peripheral tryptophan catabolism have been implicated, the exact underlying mechanism remains unknown. A role for brain-derived neurotrophic factor (BDNF) in the pathophysiology of mood disorders has recently emerged. This study examined whether depressive symptoms over time are associated with changes in serum BDNF concentration in hepatitis C patients treated with IFN-α, and whether BDNF mediates the effects of IFN-α-induced immune activation on depressive symptoms. For this purpose, 17 hepatitis C patients received IFN-α treatment with ribavirin. Patients were assessed before and at 1, 2, 4, 8, 12 and 24 wk after start of treatment. Depressive symptoms were assessed using the Montgomery-Asberg Depression Rating Scale (MADRS). In addition, cytokine concentrations and serum BDNF levels were measured at all time-points. Serum levels of BDNF decreased during the course of treatment, and were significantly and inversely associated with total MADRS score. Furthermore, pro-inflammatory cytokine levels predicted lower subsequent BDNF levels, whereas low BDNF levels, as well as increased cytokine levels, were independently associated with the development of depressive symptoms during IFN-α treatment. These findings suggest that the effect of IFN-α-induced immune activation on depression may be explained in part by alterations in neuroprotective capacity, reflected by decreases in serum BDNF following IFN-α treatment.

Electroconvulsive shock ameliorates disease processes and extends survival in huntingtin mutant mice

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by expanded polyglutamine repeats in the huntingtin (Htt) protein. Mutant Htt may damage and kill striatal neurons by a mechanism involving reduced production of brain-derived neurotrophic factor (BDNF) and increased oxidative and metabolic stress. Because electroconvulsive shock (ECS) can stimulate the production of BDNF and protect neurons against stress, we determined whether ECS treatment would modify the disease process and provide a therapeutic benefit in a mouse model of HD. ECS (50 mA for 0.2 s) or sham treatment was administered once weekly to male N171-82Q Htt mutant mice beginning at 2 months of age. Endpoints measured included motor function, striatal and cortical pathology, and levels of protein chaperones and BDNF. ECS treatment delayed the onset of motor symptoms and body weight loss and extended the survival of HD mice. Striatal neurodegeneration was attenuated and levels of protein chaperones (Hsp70 and Hsp40) and BDNF were elevated in striatal neurons of ECS-treated compared with sham-treated HD mice. Our findings demonstrate that ECS can increase the resistance of neurons to mutant Htt resulting in improved functional outcome and extended survival. The potential of ECS as an intervention in subjects that inherit the mutant Htt gene merits further consideration.

Peripheral BDNF produces antidepressant-like effects in cellular and behavioral models

Recent clinical studies demonstrate that serum levels of brain-derived neurotrophic factor (BDNF) are significantly decreased in patients with major depressive disorder (MDD) and that antidepressant treatments reverse this effect, indicating that serum BDNF is a biomarker of MDD. These findings raise the possibility that serum BDNF may also have effects on neuronal activity and behavior, but the functional significance of altered serum BDNF is unknown. To address this issue, we determined the influence of peripheral BDNF administration on depression- and anxiety-like behavior, including the forced swim test (FST), chronic unpredictable stress (CUS)/anhedonia, novelty-induced hypophagia (NIH) test, and elevated-plus maze (EPM). Furthermore, we examined adult hippocampal neurogenesis as well as hippocampal and striatal expression of BDNF, extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB), in order to determine whether peripherally administered BDNF produces antidepressant-like cellular responses in the brain. Peripheral BDNF administration increased mobility in the FST, attenuated the effects of CUS on sucrose consumption, decreased latency in the NIH test, and increased time spent in the open arms of an EPM. Moreover, adult hippocampal neurogenesis was increased after chronic, peripheral BDNF administration. We also found that BDNF levels as well as expression of pCREB and pERK were elevated in the hippocampus of adult mice receiving peripheral BDNF. Taken together, these results indicate that peripheral/serum BDNF may not only represent a biomarker of MDD, but also have functional consequences on molecular signaling substrates, neurogenesis, and behavior.

Does parasympathetic modulation prior to ECT treatment influence therapeutic outcome?

Electroconvulsive therapy (ECT) is an established treatment option for major depressive disorder when other treatments have failed. However, the underlying mechanisms responsible for these therapeutical effects are insufficiently understood to date. Furthermore, treatment outcome is difficult to predict. Recent research suggested an important role of autonomic modulation for successful treatment. We aimed to examine putative associations between autonomic modulation and response to ECT treatment and hypothesized a role for vagal modulation prior to therapy. Twenty-four patients with MDD who received ECT were assessed by means of heart rate and blood pressure variability analysis as well as baroreflex sensitivity measurements before, during and after a course of ECT. Autonomic parameters from the complete study population revealed that ECT did not significantly alter basic autonomic modulation after six sessions. Analyses showed a significant association of the reduction of HAMD scores during therapy when compared with baseline autonomic function as reflected in SDNN(RR) (p<0.004), Forbword(RR) (p<0.025) and compression entropy Hc(RR) (p<0.0003). A significant correlation was observed when overall HAMD reduction and changes of LFnu(RR) (p<0.026) or HFnu(RR) (p<0.026) during the course of therapy were analyzed. Our findings suggest that high levels of parasympathetic modulation at baseline might be associated with a beneficial effect upon ECT treatment. Adding to this, levels of parasympathetic activity seemed to increase in patients who respond to ECT treatment. Given these findings can be confirmed in future studies, autonomic modulation might be used as a predictor for therapeutic efficacy of ECT.

Is successful electroconvulsive therapy related to stimulation of the vagal system?

BACKGROUND

Electroconvulsive therapy (ECT) has been shown to exhibit strong beneficial effects in the treatment of major depressive disorder (MDD). While the exact underlying mechanisms are under debate, a role for the sympathetic response upon ECT has been suggested. When assessing patients with MDD for autonomic function, however, a loss of vagal function is prominent.

OBJECTIVE

Here, we aimed to assess the immediate effects of ECT on vagal activity and to test the hypothesis that surrogates of the latter correlate with therapeutic outcome.

METHODS

Twenty patients with MDD who underwent ECT treatment were assessed regarding their vagal function using electrophysiological measures and determination of pancreatic polypeptide (PP), which is known to be released upon vagal stimulation. Parameters were correlated to the improvement of disease severity upon ECT treatment.

RESULTS

Patients showed a significant increase of PP shortly after ECT which correlated with clinical improvement. Furthermore, the described association with the sympathetic phase after ECT could be verified.

CONCLUSION

ECT increases vagal activity which might be associated with the beneficial effect seen following this treatment. PP elevation after administration of ECT might be a useful parameter to estimate the degree of such vagal stimulation after treatment.

Peripheral BDNF produces antidepressant-like effects in cellular and behavioral models

Recent clinical studies demonstrate that serum levels of brain-derived neurotrophic factor (BDNF) are significantly decreased in patients with major depressive disorder (MDD) and that antidepressant treatments reverse this effect, indicating that serum BDNF is a biomarker of MDD. These findings raise the possibility that serum BDNF may also have effects on neuronal activity and behavior, but the functional significance of altered serum BDNF is unknown. To address this issue, we determined the influence of peripheral BDNF administration on depression- and anxiety-like behavior, including the forced swim test (FST), chronic unpredictable stress (CUS)/anhedonia, novelty-induced hypophagia (NIH) test, and elevated-plus maze (EPM). Furthermore, we examined adult hippocampal neurogenesis as well as hippocampal and striatal expression of BDNF, extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB), in order to determine whether peripherally administered BDNF produces antidepressant-like cellular responses in the brain. Peripheral BDNF administration increased mobility in the FST, attenuated the effects of CUS on sucrose consumption, decreased latency in the NIH test, and increased time spent in the open arms of an EPM. Moreover, adult hippocampal neurogenesis was increased after chronic, peripheral BDNF administration. We also found that BDNF levels as well as expression of pCREB and pERK were elevated in the hippocampus of adult mice receiving peripheral BDNF. Taken together, these results indicate that peripheral/serum BDNF may not only represent a biomarker of MDD, but also have functional consequences on molecular signaling substrates, neurogenesis, and behavior.

Brain-derived neurotrophic factor as a biomarker for mood disorders: an historical overview and future directions

Mood disorders, such as major depressive disorder (MDD) and bipolar disorder (BPD), are the most prevalent psychiatric conditions, and are also among the most severe and debilitating. However, the precise neurobiology underlying these disorders is currently unknown. One way to combat these disorders is to discover novel biomarkers for them. The development of such biomarkers will aid both in the diagnosis of mood disorders and in the development of effective psychiatric medications to treat them. A number of preclinical studies have suggested that the brain-derived neurotrophic factor (BDNF) plays an important role in the pathophysiology of MDD. In 2003, we reported that serum levels of BDNF in antidepressant-naive patients with MDD were significantly lower than those of patients medicated with antidepressants and normal controls, and that serum BDNF levels were negatively correlated with the severity of depression. Additionally, we found that decreased serum levels of BDNF in antidepressant-naive patients recovered to normal levels associated with the recovery of depression after treatment with antidepressant medication. This review article will provide an historical overview of the role played by BDNF in the pathophysiology of mood disorders and in the mechanism of action of therapeutic agents. Particular focus will be given to the potential use of BDNF as a biomarker for mood disorders. BDNF is initially synthesized as a precursor protein proBDNF, and then proBDNF is proteolytically cleaved to the mature BDNF. Finally, future perspectives on the use of proBDNF as a novel biomarker for mood disorders will be discussed.

Microarray analysis of cultured rat hippocampal neurons treated with brain derived neurotrophic factor

Brain derived neurotrophic factor (BDNF) has been shown to exert multiple actions on neurons. It plays a role in neuronal growth and maintenance and use-dependent plasticity, such as long-term potentiation and learning. This neurotrophin is believed to regulate neuronal plasticity by modifying neuronal excitability and morphology. There is experimental evidence for both an acute and a long-term effect of BDNF on synaptic transmission and structure but the molecular mechanisms underlying these events have not been completely clarified. In order to study the BDNF-induced molecular changes, the set of genes modulated in cultured hippocampal neurons by BDNF treatment was investigated after subchronic treatment with the neurotrophin. Microarray analysis performed with these cells, revealed increased expression of mRNA encoding the neuropeptides neuropeptide Y and somatostatin, and of the secreted peptide VGF (non acronymic), all of which participate in neurotransmission. In addition, the expression of genes apolipoprotein E (ApoE), delta-6 fatty acid desaturase (Fads2) and matrix metalloproteinase 14 (Mmp14), which play a role in neuronal remodelling, was also enhanced. More studies are needed to investigate and confirm the role of these genes in synaptic plasticity, but the results reported in this paper show that microarray analysis of hippocampal cultures can be used to expand our current knowledge of the molecular events triggered by BDNF in the hippocampus.

The level of serum brain-derived neurotrophic factor is associated with the therapeutic efficacy of modified electroconvulsive therapy in Chinese patients with depression

OBJECTIVE

To investigate the association between the level of serum brain-derived neurotrophic factor (sBDNF) and the therapeutic efficacy of modified electroconvulsive therapy (MECT) in Chinese patients with depressive disorder.

METHODS

Twenty-eight patients with depressive episode and 28 healthy subjects were recruited in the current study. The sBDNF level was examined in all subjects before treatment and after a 2-week treatment with MECT in patients with depression. The severity of depression was measured according to the 17-item Hamilton Rating Scale for Depression in patients with depression.

RESULTS

The severity of depression reduced significantly in patients with depression after a 2-week treatment with MECT (31.39 [SD, 4.65] vs 8.14 [5.52], P < 0.001). Serum BDNF level in patients with depression was significantly lower than that of the control group before treatment (5.66 [SD, 2.07] vs 9.17 [SD, 1.26] ng/mL, P < 0.001), then increased remarkably to the level of control subjects 2 weeks after MECT (7.90 [SD, 3.42] ng/mL). The increasing rate of sBDNF in patients with depression was significantly correlated with the decreasing rate of the total 17-item Hamilton Rating Scale for Depression score (r = 0.532, P = 0.004) and cluster scores of cognitive dysfunction (P = 0.018) and retardation (P = 0.048).

CONCLUSION

The change in sBDNF is associated with the therapeutic efficacy of MECT in Chinese patients with depression.

Serum levels of brain-derived neurotrophic factor in drug-naïve obsessive-compulsive patients: a case-control study

BACKGROUND

There is lack of data regarding BDNF serum levels in patients with obsessive-compulsive disorder (OCD). The aims of the present study were: 1) to assess the serum BDNF content in a sample of drug-naïve patients with OCD and 2) to assess whether putative alterations in peripheral BDNF may be associated to OCD severity and clinical characteristics.

METHODS

Twenty-four drug-naïve patients with a principal diagnosis of OCD were recruited. In parallel, a control group of 24 unrelated volunteers matched for gender and age was enrolled. Serum BDNF levels were measured by ELISA method.

RESULTS

The results showed that BDNF levels were decreased in OCD patients when compared to controls (36.90+/-6.42 ng/ml versus 41.59+/-7.82 ng/ml; p=0.043). No correlations were evidenced between serum BDNF content and the severity of OCD symptoms measured as Y-BOCS scores or other clinical variables.

LIMITATIONS

The choice of drug-naïve patients with obsessive-compulsive disorder had limited the size of the sample and excluded the recruitment of patients with a severe symptomatology.

CONCLUSIONS

Our findings reveal for the first time in OCD patients a decrease in serum BDNF levels. These data corroborate the hypothesis of a dysfunction in the neurotrophin expression in the OCD pathogenetic mechanism and provide the rationale for further investigations directed to the identification of novel biomarkers and new therapeutic strategies for antiobsessional treatments.

Frequency of and rationales for the combined use of electroconvulsive therapy and antiepileptic drugs in Austria and the literature

Our aim was to observe the frequency of combination therapy using antiepileptic drugs (AEDs) and electroconvulsive therapy (ECT) in Austria and the literature, and to provide rationales and recommendations based on clinical and molecular properties. The responsible ECT leaders of eight Austrian departments were contacted for information about combination therapy. A computerized PubMed database search was performed and supplemented by cross-referencing from papers, review articles and psychiatric manuals. The frequency of combination therapy in Austrian departments ranges between 0 and 85.7%. In 17 studies enrolling a total of 189 patients, 87 (46.0%) patients received combination therapy. Of these 87 patients, nine (10.3%) reported adverse effects. ECT and AEDs show overlapping clinical and molecular properties. Combination therapy is an observed reality and, according to the currently available literature, feasible. A comparison of clinical and molecular properties indicates possible augmentative effects, making combination therapy a promising alternative in treatment-resistant cases. But there is still a clear need for prospective case controlled data concerning side effects, safety profiles and effectiveness until it can be recommended.

Neurotrophic factors in serum following ECT: a pilot study

We examined changes in serum levels of a selection of neurotrophic factors, TSH, HGH and cortisol in conjunction with ECT treatment. Fifteen patients suffering from affective disorders were included, all were treated with antidepressants and psychotherapy and 10 also with ECT. The patients were examined clinically and with blood samples during treatment. Serum levels of cortisol, thyroid stimulating hormone (TSH), nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3), neuropetide Y (NPY) and human growth hormone (HGH) were studied. No significant changes were found in levels of NGF, BDNF, NT3, HGH and TSH. A change in NPY levels was statistically significant, but of uncertain clinical value as it affected only two patients. Levels of cortisol rose significantly during treatment. We did find significant correlations between the base values of NGF and HAM-D scores at inclusion and between the end-values of NT3 and NPY and the HAM-D scores prior to discharge. We were unable to reproduce findings from animal studies suggesting that a range of neurotrophic factors rise during ECT treatment. This may be because of physiological differences between animals and humans or, possibly, a result of the small number of patients included in this pilot study.

Transcranial Magnetic Stimulation: From Neurophysiology to Pharmacology, Molecular Biology and Genomics

Noninvasive plasticity paradigms, both physiologically induced and artificially induced, have come into their own in the study of the effects of genetic variation on human cortical plasticity. These techniques have the singular advantage that they enable one to study the effects of genetic variation in its natural and most relevant context, that of the awake intact human cortex, in both health and disease. This review aims to introduce the currently available artificially induced plasticity paradigms, their putative mechanisms—both in the traditional language of the systems neurophysiologist and in the evolving (and perhaps more relevant for the purposes of stimulation genomics) reinterpretation in terms of molecular neurochemistry, and highlights recent studies employing these techniques by way of examples of applications.

Electroconvulsive therapy increases glial cell-line derived neurotrophic factor (GDNF) serum levels in patients with drug-resistant depression

Electroconvulsive therapy (ECT) can be effective in patients with depression resistant to pharmacologic medication. We report that serum levels of glial cell-line derived neurotrophic factor (GDNF) were increased following ECT of patients with drug-resistant depression. When patients were sub-classified into ECT responders and non-responders, serum GDNF levels were significantly increased (58%) in responsive patients following ECT. No significant increase was seen in non-responders. These results suggest that successful ECT may be associated with elevated serum GDNF levels.

Neuronal plasticity: a link between stress and mood disorders

Although stress represents the major environmental element of susceptibility for mood disorders, the relationship between stress and disease remains to be fully established. In the present article we review the evidence in support for a role of neuronal plasticity, and in particular of neurotrophic factors. Even though decreased levels of norepinephrine and serotonin may underlie depressive symptoms, compelling evidence now suggests that mood disorders are characterized by reduced neuronal plasticity, which can be brought about by exposure to stress at different stages of life. Indeed the expression of neurotrophic molecules, such as the neurotrophin BDNF, is reduced in depressed subjects as well as in experimental animals exposed to adverse experience at early stages of life or at adulthood. These changes show an anatomical specificity and might be sustained by epigenetic mechanisms. Pharmacological intervention may normalize such defects and improve neuronal function through the modulation of the same factors that are defective in depression. Several studies have demonstrated that chronic, but not acute, antidepressant treatment increases the expression of BDNF and may enhance its localization at synaptic level. Antidepressant treatment can normalize deficits in neurotrophin expression produced by chronic stress paradigms, but may also alter the modulation of BDNF under acute stressful conditions. In summary, there is good agreement in considering neuronal plasticity, and the expression of key proteins such as the neurotrophin BDNF, as a central player for the effects of stress on brain function and its implication for psychopathology. Accordingly, effective treatments should not limit their effects to the control of neurotransmitter and hormonal dysfunctions, but should be able to normalize defective mechanisms that sustain the impairment of neuronal plasticity.

Brain-derived neurotrophic factor: role in depression and suicide

Depression and suicidal behavior have recently been shown to be associated with disturbances in structural and synaptic plasticity. Brain-derived neurotrophic factor (BDNF), one of the major neurotrophic factors, plays an important role in the maintenance and survival of neurons and in synaptic plasticity. Several lines of evidence suggest that BDNF is involved in depression, such that the expression of BDNF is decreased in depressed patients. In addition, antidepressants up-regulate the expression of BDNF. This has led to the proposal of the "neurotrophin hypothesis of depression". Increasing evidence demonstrates that suicidal behavior is also associated with lower expression of BDNF, which may be independent from depression. Recent genetic studies also support a link of BDNF to depression/suicidal behavior. Not only BDNF, but abnormalities in its cognate receptor tropomycin receptor kinase B (TrkB) and its splice variant (TrkB.T1) have also been reported in depressed/suicidal patients. It has been suggested that epigenetic modulation of the Bdnf and Trkb genes may contribute to their altered expression and functioning. More recently, impairment in the functioning of pan75 neurotrophin receptor has been reported in suicide brain specimens. pan75 neurotrophin receptor is a low-affinity neurotrophin receptor that, when expressed in conjunction with low availability of neurotropins/Trks, induces apoptosis. Overall, these studies suggest the possibility that BDNF and its mediated signaling may participate in the pathophysiology of depression and suicidal behavior. This review focuses on the critical evidence demonstrating the involvement of BDNF in depression and suicide.

Rapid antidepressant effects of sleep deprivation therapy correlates with serum BDNF changes in major depression

Recent reports have suggested that brain-derived neurotrophic factor (BDNF) levels are reduced in individuals suffering major depressive disorder and these levels normalize following antidepressant treatment. Various antidepressants and electroconvulsive therapy are shown to have a positive effect on brain-derived neurotrophic factor levels in depressive patients. The aim of this study was to assess the effect of total sleep deprivation therapy on BDNF levels in major depressive patients. Patients were assigned to two treatment groups which consisted of 22 patients in the sertraline group and 19 patients in the total sleep deprivation plus sertraline group. Patients in the sleep deprivation group were treated with three total sleep deprivations in the first week of their treatment and received sertraline. Patients in sertraline group received only sertraline. BDNF levels were measured in the two treatment groups at baseline, 7th, 14th, and 42nd days. Patients were also evaluated using the Hamilton Rating Scale for Depression (HAM-D). A control group, consisting of 33 healthy volunteers had total sleep deprivation, BDNF levels and depression measured at baseline and after the total sleep deprivation. Results showed that serum BDNF levels were significantly lower at baseline in both treatment groups compared to controls. Decreased levels of BDNF were also negatively correlated with HAM-D scores. First single sleep deprivation and a series of three sleep deprivations accelerated the treatment response that significantly decreased HAM-D scores and increased BDNF levels. Total sleep deprivation and sertraline therapy is introduced to correlate with the rapid treatment response and BDNF changes in this study.

Eletroconvulsoterapia na depressão maior: aspectos atuais

OBJETIVO: A eficácia da eletroconvulsoterapia em tratar sintomas depressivos está estabelecida por meio de inúmeros estudos desenvolvidos durante as últimas décadas. A eletroconvulsoterapia é o tratamento biológico mais efetivo para depressão atualmente disponível. O objetivo deste estudo foi demonstrar o papel da eletroconvulsoterapia no tratamento da depressão e destacar aspectos atuais relativos à sua prática. MÉTODO: Foram revisados na literatura estudos de eficácia, remissão de sintomas, fatores preditores de resposta, assim como aspectos atuais acerca da qualidade de vida, percepção dos pacientes, mecanismo de ação, técnica e prejuízo cognitivos. RESULTADOS: Os principais achados desta revisão foram: 1) a eletroconvulsoterapia é mais efetiva do que qualquer medicação antidepressiva; 2) a remissão da depressão com a eletroconvulsoterapia varia, em geral, de 50 a 80%; 3) Ainda é controverso o efeito da eletroconvulsoterapia nos níveis de fator neurotrófico derivado do cérebro (acho que aqui pode colocar entre parenteses o "BNDF"); 4) a eletroconvulsoterapia tem efeito positivo na melhora da qualidade de vida; 5) os pacientes submetidos à eletroconvulsoterapia, em geral, têm uma percepção positiva do tratamento. CONCLUSÃO: A eletroconvulsoterapia permanece sendo um tratamento altamente eficaz em pacientes com depressão resistente. Com o avanço da sua técnica, a eletroconvulsoterapia tornou-se um procedimento ainda mais seguro e útil tanto para a fase aguda, quanto para a prevenção de novos episódios depressivos.

Antiapoptotic and neurotrophic effects of antidepressants: a review of clinical and experimental studies

Recent studies have strengthened the role of the abnormalities in neurotrophic pathways in the pathophysiology of depression. It has been shown that the depletion of growth factors, particularly brain-derived neurotrophic factor, may result in depression-like behavior in animals and may induce cellular changes that are reminiscent of those observed in depressed patients. Some authors even suggested that increased neuronal cell loss may contribute to the pathogenesis of depression. Hence, appreciable interest has been focused on the trophic and antiapoptotic effects of antidepressant drugs. In this paper, we put emphasis on the contribution of hippocampal atrophy, increased cell death and alterations in trophic factors to the pathogenesis of depression and their relationship to the potential of antidepressants to reverse these changes by modulating trophic factor cascades and preventing apoptosis. First, evidences for increased hippocampal atrophy and cell death in depression are discussed, followed by a review of selected studies of special interest that concern antiapoptotic action of antidepressant drugs. Next, depression-related neurotrophic abnormalities and their reversal by antidepressants are depicted. Finally, relationships among neurotrophins, antiapoptotic proteins and antioxidant enzymes in the pathology and treatment of depression are pointed out.

Serum brain-derived neurotrophic factor (BDNF) is not associated with response to electroconvulsive therapy (ECT): a pilot study in drug resistant depressed patients

Refractory depression is a highly debilitating mental condition that originates major social and economic burden. About 50% of the patients experience a chronic course of illness and up to 20% show an insufficient response to drug treatments. Electroconvulsive therapy (ECT) is the most effective treatment method in refractory depression, although its mechanism of action is still unknown. Brain-derived neurotrophic factor (BDNF) is decreased in depressive episodes, and increases with antidepressant treatment, being suggested as a biomarker of response to ECT. We report the findings of a study on the effects of ECT on BDNF and clinical outcomes in a group of drug resistant depressive patients before and after ECT. The patients post-ECTs have shown an important improvement of depressive symptomatology on the HDRS (p=0.001), of psychotic features on the BPRS (p=0.001) and of the severity of illness on the CGI (p=0.001). There were no changes in the serum BDNF before and after the ECT treatment (p=0.89). These results do not support the hypothesis that the clinical improvement following ECT is due to changes in the BDNF.

Neurophysiological mechanisms of electroconvulsive therapy for depression

The neurobiological foundation of electroconvulsive therapy (ECT) remains fragile. How ECT affects neural activities in the brain of depressives is largely unknown. There has been accumulating knowledge on genes and molecules induced by the animal model of ECT. Exact functions of those molecules in the context of mood disorder remain unknown. Among the dozens of molecules highly expressed by ECT, one that shows an especially prominent induction (>6-fold) is Homer 1a, a member of the intracellular scaffold protein family Homer. We have examined effects of Homer 1a in ECT-subjected cortical pyramidal cells, on the basis of which two neurobiological consequences of ECT are proposed. First, Homer 1a either injected intracellularly or induced by ECT was shown to reduce neuronal excitability. This agrees with diverse lines of mutually consistent clinical investigations, which unanimously point to an enhanced excitability in the cerebral cortex of depressive patients. The GABAergic dysfunction hypothesis of depression was thus revitalized. Second, again by relying on Homer 1a, we have proposed a molecular mechanism by which ECT affects a form of long-term depression (LTD). The possibility is discussed that clinical effects of ECT are exerted at least partly by reducing neural excitability and modifying synaptic plasticity.

A systematic review and meta-analysis of clinical studies on major depression and BDNF levels: implications for the role of neuroplasticity in depression

Several clinical studies on major depressive disorder (MDD) have shown that blood brain-derived neurotrophic factor (BDNF) - a factor used to index neuroplasticity - is associated with depression response; however, the results are mixed. The purpose of our study was to evaluate whether BDNF levels are correlated with improvement of depression. We performed a systematic review and meta-analysis of the literature, searching Medline, Cochrane Central, SciELO databases and reference lists from retrieved articles for clinical studies comparing mean BDNF blood levels in depressed patients pre- and post-antidepressant treatments or comparing depressed patients with healthy controls. Two reviewers independently searched for eligible studies and extracted outcome data using a structured form previously elaborated. Twenty articles, including 1504 subjects, met our inclusion criteria. The results showed that BDNF levels increased significantly after antidepressant treatment (effect size 0.62, 95% CI 0.36-0.88, random effects model). In addition, there was a significant correlation between changes in BDNF level and depression scores changes (p=0.02). Moreover, the results were robust according to the sensitivity analysis and Begg's funnel plot results did not suggest publication bias. Finally, there was a difference between pre-treatment patients and healthy controls (effect size 0.91, 95% CI 0.70-1.11) and a small but significant difference between treated patients and healthy controls (effect size 0.34, 95% CI 0.02-0.66). Our results show that BDNF levels are associated with clinical changes in depression; supporting the notion that depression improvement is associated with neuroplastic changes.

Neuropeptides in depression: role of VGF

The monoamine hypothesis of depression is increasingly called into question by newer theories that revolve around changes in neuronal plasticity, primarily in the hippocampus, at both the structural and the functional levels. Chronic stress negatively regulates hippocampal function while antidepressants ameliorate the effects of stress on neuronal morphology and activity. Both stress and antidepressants have been shown to affect levels of brain-derived neurotrophic factor (BDNF) whose transcription is dependent on cAMP response element binding protein (CREB). BDNF itself has antidepressant-like actions and can induce transcription of a number of molecules. One class of genes regulated by both BDNF and serotonin (5-HT) are neuropeptides including VGF (non-acryonimic) which has a novel role in depression. Neuropeptides are important modulators of neuronal function but their role in affective disorders is just emerging. Recent studies demonstrate that VGF, which is also a CREB-dependent gene, is upregulated by antidepressant drugs and voluntary exercise and is reduced in animal models of depression. VGF enhances hippocampal synaptic plasticity as well as neurogenesis in the dentate gyrus but the mechanisms of antidepressant-like actions of VGF in behavioral paradigms are not known. We summarize experimental data describing the roles of BDNF, VGF and other neuropeptides in depression and how they may be acting through the generation of new neurons and altered synaptic activity. Understanding the molecular and cellular changes that underlie the actions of neuropeptides and how these adaptations result in antidepressant-like effects will aid in developing drugs that target novel pathways for major depressive disorders.

Association between brain-derived neurotrophic factor gene and a severe form of bipolar disorder, but no interaction with the serotonin transporter gene

BACKGROUND

Recent data suggest that brain-derived neurotrophic factor (BDNF) and the serotonergic system are involved and interact in major depressive disorder and suicidal behavior (SB). Several family and population-based studies have reported associations between the BDNF gene and serotonin-related genes, specifically the serotonin transporter (5HTT) gene, with bipolar disorder (BD) and SB. However, despite the fact that gene-by-gene interaction between BDNF and 5HTT has been demonstrated in monoamine deficiencies in animals, this kind of interaction has never been tested in humans. Our hypothesis is that some BDNF and 5HTT polymorphisms might confer increased risk for BD and SB and that both genes may interact with each other.

METHODS

To test this hypothesis, we genotyped the most common BDNF polymorphisms, G196A (Val66Met), A-633T and BDNF-LCPR, as well as 5HTT (5HTT-LPR), in 447 BD patients and 370 controls.

RESULTS

We replicated the association previously reported between BDNF G196A (Val66Met) polymorphism and BD. We also observed a correlation between the number of G196 alleles and short alleles of 5HTT-LPR and the severity of SB in BD. However, we found no significant interaction between these two markers.

CONCLUSIONS

These results suggest that BDNF G196A as well as 5HTT-LPR polymorphisms confer risk for SB in BD, but we did not observe any evidence for an interaction between them.

Efficacy of electroconvulsive therapy is associated with changing blood levels of homovanillic acid and brain-derived neurotrophic factor (BDNF) in refractory depressed patients: a pilot study

Electroconvulsive therapy (ECT) is effective for patients with antidepressant medication-resistant depression. However, the mechanisms of ECT's effectiveness for treating depression are not fully understood. We therefore investigated ECT's effects on blood levels of brain-derived neurotrophic factor (BDNF), catecholamine metabolites, and nitric oxide (NO) in 18 treatment-refractory depressed patients. Serum BDNF levels increased significantly following ECT in responders to ECT (before ECT: 8.0+/-9.7 ng/mL; five weeks after start of ECT: 15.1+/-11.1 ng/mL), whereas BDNF levels in non-responders were unchanged (before ECT: 11.5+/-11.0 ng/mL; five weeks after start of ECT: 9.4+/-7.5 ng/mL). Furthermore, the plasma HVA levels, but not MHPG levels, were significantly reduced after ECT (before ECT: 8.5+/-1.9 ng/mL; five weeks after start of ECT: 5.8+/-2.2 ng/mL). This latter finding occurred in parallel with the improvement of depressive symptoms in all patients. These results suggest that the mechanisms underlying ECT's effect on refractory depression may be related to dopaminergic neurons and BDNF.

The role of neurotrophic factors in adult hippocampal neurogenesis, antidepressant treatments and animal models of depressive-like behavior

Major depressive disorder (MDD) is characterized by structural and neurochemical changes in limbic structures, including the hippocampus, that regulate mood and cognitive functions. Hippocampal atrophy is observed in patients with depression and this effect is blocked or reversed by antidepressant treatments. Brain-derived neurotrophic factor and other neurotrophic/growth factors are decreased in postmortem hippocampal tissue from suicide victims, which suggests that altered trophic support could contribute to the pathophysiology of MDD. Preclinical studies demonstrate that exposure to stress leads to atrophy and cell loss in the hippocampus as well as decreased expression of neurotrophic/growth factors, and that antidepressant administration reverses or blocks the effects of stress. Accumulating evidence suggests that altered neurogenesis in the adult hippocampus mediates the action of antidepressants. Chronic antidepressant administration upregulates neurogenesis in the adult hippocampus and this cellular response is required for the effects of antidepressants in certain animal models of depression. Here, we review cellular (e.g. adult neurogenesis) and behavioral studies that support the neurotrophic/neurogenic hypothesis of depression and antidepressant action. Aberrant regulation of neuronal plasticity, including neurogenesis, in the hippocampus and other limbic nuclei may result in maladaptive changes in neural networks that underlie the pathophysiology of MDD.

Strategy to Develop a New Drug for Treatment-resistant Depression—Role of Electroconvulsive Stimuli and BDNF—

In recent years, depression studies have focused on morphological changes associated with depression. Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor that plays an important role in the morphological changes associated with depression and the mechanisms of antidepressants. On the other hand, hyperfunction of the hypothalamic-pituitary-adrenal axis has been link to pathophysiology of depression. In our previous studies, ACTH-treated rats served as a valuable animal model of tricyclic antidepressant-resistant depressive conditions. However, few neuroanatomic studies have been done. In the present study, we investigated mechanisms underling ACTH-treated rat serving an imipramine treatment-resistant depression model using c-Fos as a marker. The c-Fos immunohistochemical study indicated that the medial prefrontal cortex is an action site of imipramine in ACTH-treated rats. Electroconvulsive therapy is considered an effective treatment for treatment-resistant depression. However, the mechanisms causing treatment-resistant depressive conditions are unknown. We investigated the effect of repeated electrical convulsive shock (ECS)-treatment using the forced swim test, a screening method for antidepressant-like activity, and hippocampal BDNF protein levels in ACTH-treated rats. Findings showed that repeated ECS treatment decreased the immobility time during forced swim test. Furthermore, the ECS treatment also markedly increased the hippocampal BDNF levels in the rat tricyclic antidepressant-resistant depression model. In addition, the repeated ECS treatment showed long-lasting effects on forced swim test and increased of hippocampal BDNF levels in normal rats. These findings suggest that BDNF plays a key role in the antidepressant-like effect of ECS and that increased BDNF may be involved in promoting the long-lasting effect.