BDNF-Val66Met-polymorphism impact on cortical plasticity in schizophrenia patients: a proof-of-concept study

BACKGROUND

Brain-derived neurotrophic factor (BDNF) has been shown to be a moderator of neuroplasticity. A frequent BDNF-polymorphism (Val66Met) is associated with impairments of cortical plasticity. In patients with schizophrenia, reduced neuroplastic responses following non-invasive brain stimulation have been reported consistently. Various studies have indicated a relationship between the BDNF-Val66Met-polymorphism and motor-cortical plasticity in healthy individuals, but schizophrenia patients have yet to be investigated. The aim of this proof-of-concept study was, therefore, to test the impact of the BDNF-Val66Met-polymorphism on inhibitory and facilitatory cortical plasticity in schizophrenia patients.

METHODS

Cortical plasticity was investigated in 22 schizophrenia patients and 35 healthy controls using anodal and cathodal transcranial direct-current stimulation (tDCS) applied to the left primary motor cortex. Animal and human research indicates that excitability shifts following anodal and cathodal tDCS are related to molecular long-term potentiation and long-term depression. To test motor-cortical excitability before and after tDCS, well-established single- and paired-pulse transcranial magnetic stimulation protocols were applied.

RESULTS

Our analysis revealed increased glutamate-mediated intracortical facilitation in met-heterozygotes compared to val-homozygotes at baseline. Following cathodal tDCS, schizophrenia met-heterozygotes had reduced gamma-amino-butyric-acid-mediated short-interval intracortical inhibition, whereas healthy met-heterozygotes displayed the opposite effect. The BDNF-Val66Met-polymorphism did not influence single-pulse motor-evoked potential amplitudes after tDCS.

CONCLUSIONS

These preliminary findings support the notion of an association of the BDNF-Val66Met-polymorphism with observable alterations in plasticity following cathodal tDCS in schizophrenia patients. This indicates a complex interaction between inhibitory intracortical interneuron-networks, cortical plasticity, and the BDNF-Val66Met-polymorphism. Further replication and validation need to be dedicated to this question to confirm this relationship.

Assessment of diabetes acceptance can help identify patients with ineffective diabetes self-care and poor diabetes control

AIMS

To estimate the associations between insufficient diabetes acceptance and relevant diabetes outcomes.

METHODS

A total of 320 patients completed questionnaires on diabetes non-acceptance (the Acceptance and Action Diabetes Questionnaire), diabetes distress (the Problem Areas in Diabetes Scale), depressive mood (the Center for Epidemiologic Studies Depression Scale), coping with illness (the Freiburg Questionnaire of Coping with Illness), self-care activities (the Summary of Diabetes Self-Care Activities Measure) and quality of life (the Short Form-36 Health Questionnaire). A six-item version of the Acceptance and Action Diabetes Questionnaire showing good reliability and validity was established, and the associations between insufficient acceptance and clinical outcomes were estimated.

RESULTS

Higher diabetes non-acceptance correlated significantly with less active coping (-0.37), reduced self-care (-0.43) and higher HbA1c levels (0.31), higher diabetes distress (0.53) and more depressive symptoms (0.36). Correlations of diabetes non-acceptance with diabetes self-care/glycaemic control were significantly higher than were those of depressive mood or diabetes distress with these criteria.

CONCLUSIONS

Low diabetes acceptance is associated with impaired self-care and glycaemic control. Assessment of diabetes acceptance may facilitate the detection of patients at high risk and may present an essential target for treatments to improve diabetes control that is more relevant than elevated depressive mood or diabetes distress.

Ten years of proteomics in multiple sclerosis

Multiple sclerosis, which is the most common cause of chronic neurological disability in young adults, is an inflammatory, demyelinating, and neurodegenerative disease of the CNS, which leads to the formation of multiple foci of demyelinated lesions in the white matter. The diagnosis is based currently on magnetic resonance image and evidence of dissemination in time and space. However, this could be facilitated if biomarkers were available to rule out other disorders with similar symptoms as well as to avoid cerebrospinal fluid analysis, which requires an invasive collection. Additionally, the molecular mechanisms of the disease are not completely elucidated, especially those related to the neurodegenerative aspects of the disease. The identification of biomarker candidates and molecular mechanisms of multiple sclerosis may be approached by proteomics. In the last 10 years, proteomic techniques have been applied in different biological samples (CNS tissue, cerebrospinal fluid, and blood) from multiple sclerosis patients and in its experimental model. In this review, we summarize these data, presenting their value to the current knowledge of the disease mechanisms, as well as their importance in identifying biomarkers or treatment targets.

QCD and strongly coupled gauge theories: challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.

Stereological investigation of the posterior hippocampus in affective disorders

Hippocampus volumes have been shown to be decreased in patients with major depression, but volume measurements are inconsistent in patients with bipolar disorder. Both disorders are associated with deficits in hippocampus-mediated cognitive functions. However, the underlying pathophysiology is widely unknown. In this post-mortem study, we used design-based stereology on Nissl-stained serial sections to investigate the number of neurons, oligodendrocytes and astrocytes in substructures of the posterior hippocampus in eight patients with major depression, eight patients with bipolar disorder and ten control patients without a neuropsychiatric disorder. Compared to controls, patients with bipolar disorder had significantly more neurons in the cornu ammonis subfield 1 (CA1) and the subiculum, while the number of oligodendrocytes was higher only in CA1. In patients with major depression, the density of oligodendrocytes was higher in CA2/3, CA4 and the subiculum. The dose of antidepressants correlated with the density and number of oligodendrocytes in CA2/3, indicating that antidepressants may affect our results. Treatment with neuroleptics expressed in chlorpromazine equivalents and benzodiazepines expressed in diazepam equivalents correlated negatively with the number of oligodendrocytes in CA2/3 and CA4, respectively, suggesting that treatment with these drugs do not influence cell number. We did not detect alterations in either volumes of substructures or numbers of astrocytes. Increased cell numbers argue for a denser packing of neurons and oligodendrocytes as a result of a decreased neuropils. This neuropathological process may be based on neurodevelopmental disturbances and may contribute to altered microconnectivity and cognitive deficits in affective disorders.

Sex-dependent metabolic alterations of rat liver after 12-week exposition to haloperidol or clozapine

Antipsychotic drugs are known to have sex-dependent effects on metabolic homeostasis. Liver plays a crucial role in drug degradation as well as in glucose and lipid metabolism. The present study examines the influence of clozapine and haloperidol on metabolic liver parameters. Over 12 weeks, male and female Sprague-Dawley rats were fed ground pellets containing clozapine or haloperidol. Liver mass was weighed and liver index calculated. Liver transaminases (ALAT, ALP), malondialdehyde, glucose, triglycerides, total cholesterol, HDL-cholesterol, and glycogen were determined. Finally, SREBP-1 and SREBP-2 as well as neutral fat deposits were examined. In male rats fed with clozapine, we found increased liver mass correlated with an increased liver index, high triglyceride levels, a high ratio of SREBP-1, and an elevated neutral fat distribution. Male and female haloperidol treated rats showed decreased liver mass and increased neutral fat deposition. Malondialdehyde was increased in all rats receiving antipsychotic medication indicating elevated oxidative stress. In both male and female clozapine treated rats, we found glycogen depletion related to decreased glucose levels in females. While liver transaminases were unchanged in the clozapine group, ALAT was elevated after haloperidol treatment in both sexes. Chronic clozapine intake exerts sex-dependent effects on hepatic metabolism. Although haloperidol has been shown to change fewer metabolic parameters, it causes oxidative stress and neutral fat deposits in liver tissue in both sexes.

Mesenchymal stromal cells inhibit proliferation of virus-specific CD8(+) T cells

Mesenchymal stromal cells (MSCs) possess broad immunomodulatory capacities that are currently investigated for potential clinical application in treating autoimmune disorders. Third-party MSCs suppress alloantigen-induced proliferation of peripheral blood mononuclear cells providing the rationale for clinical use in graft-versus-host disease (GvHD). We confirmed that MSCs strongly inhibited proliferation of CD8(+) T cells in a mixed lymphocyte reaction. However, MSCs also suppressed proliferation of T cells specifically recognizing cytomegalovirus (CMV) and influenza virus. Inhibition was dose dependent, but independent of the culture medium. MSCs inhibited proliferation of specific CD8(+) T cells and the release of IFN-γ by specific CD8(+) T cells for immunodominant HLA-A2- and HLA-B7- restricted antigen epitopes derived from CMV phosphoprotein 65 and influenza matrix protein. This is in contrast to a recently reported scenario where MSCs exert differential effects on alloantigen and virus-specific T cells potentially having an impact on surveillance and prophylaxis of patients treated by MSCs.

[The glutamate hypothesis of schizophrenia]

For many years, the dopamine hypothesis of schizophrenia has been the leading theory explaining the aetiology of schizophrenia. However, since the first observation showed that NMDA-receptor antagonists (e. g., PCP) can induce all kinds of schizophrenia symptoms in humans, the glutamate hypothesis of schizophrenia has been established as an additional explanation model. Apart from the PCP-induced psychoses, many other findings from all areas of modern neuroscience have confirmed and extended the glutamate hypothesis. This review discusses the available evidence for the glutamate hypothesis and puts the different findings into relation. Consecutively, the possibilities for a pharmacological modulation of the glutamate system and recent clinical trials are discussed. To sum up, one could note that the glutamate hypothesis of schizophrenia is now well-established. The development of glutamatergic antipsychotics is still in the early stages, but there is hope for a new generation of antipsychotics based on the glutamate hypothesis of schizophrenia. However, recent findings from registration trials could not provide positive findings for the recently developed glutamatergic drugs.

Gene expression in superior temporal cortex of schizophrenia patients

We investigated gene expression pattern obtained from microarray data of 10 schizophrenia patients and 10 control subjects. Brain tissue samples were obtained postmortem; thus, the different ages of the patients at death also allowed a study of the dynamic behavior of the expression patterns over a time frame of many years. We used statistical tests and dimensionality reduction methods to characterize the subset of genes differentially expressed in the two groups. A set of 10 genes were significantly downregulated, and a larger set of 40 genes were upregulated in the schizophrenia patients. Interestingly, the set of upregulated genes includes a large number of genes associated with gene transcription (zinc finger proteins and histone methylation) and apoptosis. We furthermore identified genes with a significant trend correlating with age in the control (MLL3) or the schizophrenia group (SOX5, CTRL). Assessments of correlations of other genes with the disorder (RRM1) or with the duration of medication could not be resolved, because all patients were medicated. This hypothesis-free approach uncovered a series of genes differentially expressed in schizophrenia that belong to a number of distinct cell functions, such as apoptosis, transcriptional regulation, cell motility, energy metabolism and hypoxia.

S100B is downregulated in the nuclear proteome of schizophrenia corpus callosum

Here we report the downregulation of S100B in the nuclear proteome of the corpus callosum from nine schizophrenia patients compared to seven mentally healthy controls. Our data have been obtained primarily by mass spectrometry and later confirmed by Western blot. This is an intriguing finding coming from a brain region which is essentially composed by white matter, considering the potential role of S100B in the control of oligodendrocyte maturation. This data reinforce the importance of oligodendrocytes in schizophrenia, shedding more light to its pathobiology.

CACNA1C genotype explains interindividual differences in amygdala volume among patients with schizophrenia

Affective deficits are one common denominator of schizophrenia (SZ), bipolar disorder (BD) and obsessive compulsive disorder (OCD) with the amygdala indicated as one of the major structures involved in emotion regulation. Previous findings of differences in amygdala volume between healthy controls and patients with SZ, BD or OCD diverge with respect to the affected hemisphere, size and direction of the effect. Variability in the CACNA1C gene has been linked to BD, SZ as well as structural and functional variation in the amygdala in healthy people and patients with BD. We were interested to investigate whether amygdala volumes differ between hemispheres, diagnostic or genotype groups, and whether any interactive effects exist. We combined genotyping of SNP rs1006737 in CACNA1C with structural MRI measurements of relative gray matter (GM) amygdala volume in patients with SZ, BD or OCD as well as healthy controls (N Total = 72). The CACNA1C genotype showed a significant effect on relative GM amygdala volume in patients with SZ. There was a significant left versus right relative GM amygdala volume decrease in patients with SZ or BD. The effects of hemisphere and diagnosis (controls vs. patients with SZ) on relative GM amygdala volume were genotype specific. Our data suggest that the CACNA1C genotype may account for some heterogeneity in the effects of hemisphere and diagnosis on amygdala volume when comparing patients with SZ and controls and point to disturbed Ca(2+)-signaling as a plausible mechanism contributing to the pathology in patients with SZ.

The impact of environmental factors in severe psychiatric disorders

During the last decades, schizophrenia has been regarded as a developmental disorder. The neurodevelopmental hypothesis proposes schizophrenia to be related to genetic and environmental factors leading to abnormal brain development during the pre- or postnatal period. First disease symptoms appear in early adulthood during the synaptic pruning and myelination process. Meta-analyses of structural MRI studies revealing hippocampal volume deficits in first-episode patients and in the longitudinal disease course confirm this hypothesis. Apart from the influence of risk genes in severe psychiatric disorders, environmental factors may also impact brain development during the perinatal period. Several environmental factors such as antenatal maternal virus infections, obstetric complications entailing hypoxia as common factor or stress during neurodevelopment have been identified to play a role in schizophrenia and bipolar disorder, possibly contributing to smaller hippocampal volumes. In major depression, psychosocial stress during the perinatal period or in adulthood is an important trigger. In animal studies, chronic stress or repeated administration of glucocorticoids have been shown to induce degeneration of glucocorticoid-sensitive hippocampal neurons and may contribute to the pathophysiology of affective disorders. Epigenetic mechanisms altering the chromatin structure such as histone acetylation and DNA methylation may mediate effects of environmental factors to transcriptional regulation of specific genes and be a prominent factor in gene-environmental interaction. In animal models, gene-environmental interaction should be investigated more intensely to unravel pathophysiological mechanisms. These findings may lead to new therapeutic strategies influencing epigenetic targets in severe psychiatric disorders.

Rates and predictors of remission in first-episode schizophrenia within 1 year of antipsychotic maintenance treatment. Results of a randomized controlled trial within the German Research Network on Schizophrenia

OBJECTIVE

Full and sustained symptom remission is a major treatment objective after a first-episode in schizophrenia. Findings regarding differences in remission between first- and second-generation antipsychotics are inconclusive. This study aimed to provide rates and predictors of remission in first-episode schizophrenia and to identify symptoms that prevent remission.

METHODS

Prevalence rates of "symptomatic remission" (symptom criteria only) and "enduring remission" (symptom and 6-month time criteria), defined according to Andreasen et al. (2005), were determined in first-episode patients participating in a RCT by the German Research Network on Schizophrenia (GRNS) that compared post-acute, 1-year maintenance treatment with risperidone or haloperidol. Respective predictors at baseline were identified by logistic and Cox regression analysis.

RESULTS

Prevalence rates were 91.5% for symptomatic remission (n=152/166 eligible patients) and 58.6% for enduring remission (n=65 of 111 patients who continued for at least 6 months; 39.2% of all 166 patients included), with no significant differences between risperidone and haloperidol in either type of remission. Enduring remission often was not reached because of negative symptoms: After 6 months, 40.5% of the patients had at least 1 negative symptom, whereas only 10.8% of the patients had "persisting" positive symptoms. Of the different predictors identified in univariate analyses, (lower) negative symptoms and participating in standardized psychological treatment remained significant in multivariate (stepwise forward) analyses for enduring remission.

CONCLUSIONS

By far most of the first-episode patients reached a temporary state of full symptomatic remission within 1 year of antipsychotic treatment. However, only about 50% achieved sustained, enduring remission. Negative symptoms are still a major treatment obstacle to enduring remission in schizophrenia.

Deciphering the human brain proteome: characterization of the anterior temporal lobe and corpus callosum as part of the Chromosome 15-centric Human Proteome Project

Defining the proteomes encoded by each chromosome and characterizing proteins related to human illnesses are among the goals of the Chromosome-centric Human Proteome Project (C-HPP) and the Biology and Disease-driven HPP. Following these objectives, we investigated the proteomes of the human anterior temporal lobe (ATL) and corpus callosum (CC) collected post-mortem from eight subjects. Using a label-free GeLC-MS/MS approach, we identified 2454 proteins in the ATL and 1887 in the CC through roughly 7500 and 5500 peptides, respectively. Considering that the ATL is a gray-matter region while the CC is a white-matter region, they presented proteomes specific to their functions. Besides, 38 proteins were found to be differentially expressed between the two regions. Furthermore, the proteome data sets were classified according to their chromosomal origin, and five proteins were evidenced at the MS level for the first time. We identified 70 proteins of the chromosome 15 - one of them for the first time by MS - which were submitted to an in silico pathway analysis. These revealed branch point proteins associated with Prader-Willi and Angelman syndromes and dyskeratosis congenita, which are chromosome-15-associated diseases. Data presented here can be a useful for brain disorder studies as well as for contributing to the C-HPP initiative. Our data are publicly available as resource data to C-HPP participant groups at http://yoda.iq.ufrj.br/Daniel/chpp2013. Additionally, the mass spectrometry proteomics data have been deposited to the ProteomeXchange with identifier PXD000547 for the corpus callosum and PXD000548 for the anterior temporal lobe.

Effects of cannabis and familial loading on subcortical brain volumes in first-episode schizophrenia

Schizophrenia is a severe neuropsychiatric disorder with familial loading as heritable risk factor and cannabis abuse as the most relevant environmental risk factor up to date. Cannabis abuse has been related to an earlier onset of the disease and persisting cannabis consumption is associated with reduced symptom improvement. However, the underlying morphological and biochemical brain alterations due to these risk factors as well as the effects of gene-environmental interaction are still unclear. In this magnetic resonance imaging (MRI) study in 47 first-episode schizophrenia patients and 30 healthy control subjects, we investigated effects of previous cannabis abuse and increased familial risk on subcortical brain regions such as hippocampus, amygdala, caudate nucleus, putamen, thalamus and subsegments of the corpus callosum (CC). In a subsequent single-volume (1)H-magnetic resonance spectroscopy study, we investigated spectra in the left hippocampus and putamen to detect metabolic alterations. Compared to healthy controls, schizophrenia patients displayed decreased volumes of the left hippocampus, bilateral amygdala and caudate nucleus as well as an increased area of the midsagittal CC1 segment of the corpus callosum. Patients fulfilling the criteria for cannabis abuse at admission showed an increased area of the CC2 segment compared to those who did not fulfill the criteria. Patients with a family history of schizophrenia combined with previous cannabis abuse showed lower volumes of the bilateral caudate nucleus compared to all other patients, implicating an interaction between the genetic background and cannabis abuse as environmental factor. Patients with cannabis abuse also had higher ratios of N-acetyl aspartate/choline in the left putamen, suggesting a possible neuroprotective effect in this area. However, antipsychotic medication prior to MRI acquisition and gender effects may have influenced our results. Future longitudinal studies in first-episode patients with quantification of cannabis abuse and assessment of schizophrenia risk genes are warranted.