Typical and atypical neuroleptics induce alteration in blood-brain barrier and brain 59FeCl3 uptake

Elucidating of the metabolic impact of risperidone on brain microvascular endothelial cells using untargeted metabolomics-based LC-MS

Risperidone is useful for the treatment of schizophrenia symptoms; however, it also has side effects, and an overdose can be harmful. The metabolic effects of risperidone at high therapeutic doses and its metabolites have not been elucidated. Endogenous cellular metabolites may be comprehensively analyzed using untargeted metabolomics-based liquid chromatography-mass spectrometry (LC-MS), which can reveal changes in cell regulation and metabolic pathways. By identifying the metabolites and pathway changes using a nontargeted metabolomics-based LC-MS approach, we aimed to shed light on the potential toxicological effects of high-dose risperidone on brain microvascular endothelial cells (MVECs) associated with the human blood brain barrier. A total of 42 metabolites were selected as significant putative metabolites of the toxicological response of high-dose risperidone in MVECs. Six highly correlated pathways were identified, including those involving diacylglycerol, fatty acid, ceramide, glycerophospholipid, amino acid, and tricarboxylic acid metabolism. We demonstrated that methods focused on metabolomics are useful for identifying metabolites that may be used to clarify the mechanism of drug-induced toxicity.

Perturbed iron biology in the prefrontal cortex of people with schizophrenia

Despite loss of grey matter volume and emergence of distinct cognitive deficits in young adults diagnosed with schizophrenia, current treatments for schizophrenia do not target disruptions in late maturational reshaping of the prefrontal cortex. Iron, the most abundant transition metal in the brain, is essential to brain development and function, but in excess, it can impair major neurotransmission systems and lead to lipid peroxidation, neuroinflammation and accelerated aging. However, analysis of cortical iron biology in schizophrenia has not been reported in modern literature. Using a combination of inductively coupled plasma-mass spectrometry and western blots, we quantified iron and its major-storage protein, ferritin, in post-mortem prefrontal cortex specimens obtained from three independent, well-characterised brain tissue resources. Compared to matched controls (n = 85), among schizophrenia cases (n = 86) we found elevated tissue iron, unlikely to be confounded by demographic and lifestyle variables, by duration, dose and type of antipsychotic medications used or by copper and zinc levels. We further observed a loss of physiologic age-dependent iron accumulation among people with schizophrenia, in that the iron level among cases was already high in young adulthood. Ferritin, which stores iron in a redox-inactive form, was paradoxically decreased in individuals with the disorder. Such iron-ferritin uncoupling could alter free, chemically reactive, tissue iron in key reasoning and planning areas of the young-adult schizophrenia cortex. Using a prediction model based on iron and ferritin, our data provide a pathophysiologic link between perturbed cortical iron biology and schizophrenia and indicate that achievement of optimal cortical iron homeostasis could offer a new therapeutic target.

Sex-dependent alterations of dopamine receptor and glucose transporter density in rat hypothalamus under long-term clozapine and haloperidol medication

OBJECTIVE

Sex-dependent disturbances of peripheral glucose metabolism are known complications of antipsychotic drug treatment. The influence of long-term clozapine and haloperidol medication on hypothalamus, maintaining aspects of internal body homeostasis, has not yet been completely clarified.

METHODS

After puberty, male and female Sprague Dawley rats were fed orally with ground pellets containing haloperidol (1 mg/kgBW/day) or clozapine (20 mg/kgBW/day) for 12 weeks. The hypothalamic protein expression of dopamine receptors D2R and D4R, melanocortin receptor MC4R, and glucose transporters Glut1 and Glut3 was examined. Glucose, glycogen, lactate, and pyruvate levels were determined, also malondialdehyde equivalents as markers of oxidative stress.

RESULTS

D2R expression was increased in the male haloperidol and clozapine group but decreased in females medicated with clozapine. D4R expression was upregulated under clozapine medication. While females showed increased Glut1, Glut3 was elevated in both male and female clozapine-medicated animals. We found no changes of hypothalamic malondialdehyde, glycogen, and MC4R. Hypothalamic lactate was elevated in the female clozapine group.

CONCLUSION

Clozapine sex-dependently affects the expression of D2R, Glut1, and Glut3. The upregulation of the glucose transporters indicates glucose deprivation in the endothelial cells and consequently in astrocytes and neurons. Increased hypothalamic lactate in females under clozapine points to enhanced glycolysis with a higher glucose demand to produce the required energy. Haloperidol did not change the expression of the glucose transporters and upregulated D2R only in males.

Genetics of tardive dyskinesia: Promising leads and ways forward

Tardive dyskinesia (TD) is a potentially irreversible and often debilitating movement disorder secondary to chronic use of dopamine receptor blocking medications. Genetic factors have been implicated in the etiology of TD. We therefore have reviewed the most promising genes associated with TD, including DRD2, DRD3, VMAT2, HSPG2, HTR2A, HTR2C, and SOD2. In addition, we present evidence supporting a role for these genes from preclinical models of TD. The current understanding of the etiogenesis of TD is discussed in the light of the recent approvals of valbenazine and deutetrabenazine, VMAT2 inhibitors, for treating TD.

Biomarkers for drug development in early psychosis: Current issues and promising directions

A major goal of current research in schizophrenia is to understand the biology underlying onset and early progression and to develop interventions that modify these processes. Biomarkers can play a critical role in identifying disease state, factors contributing to underlying progression, as well as predicting and monitoring response to treatment. Once biomarker-based therapeutics are established, biomarkers can guide treatment selection. It is increasingly clear that a wide range of potential biomarkers should be examined in schizophrenia, given the large number of genetic and environmental factors that have been identified as risk factors. New models for analysis of biomarkers are needed that represent the central nervous system as a highly complex, dynamic, and interactive system. Many tools are available with which to study relevant brain chemistry, but most are indirect measures and represent only a small fraction of the potential etiologic factors contributing to the molecular, structural and functional components of schizophrenia. This review represents the work of the International Society for CNS Clinical Trials and Methodology (ISCTM) Biomarkers Working Group. It discusses advantages and disadvantages of different categories of biomarkers and provides a summary of evidence that biomarkers representing inflammation, oxidative stress, endocannabinoids, glucocorticoid, and biogenic amines systems are dysregulated and potentially interactive in early phase schizophrenia. As has been recently demonstrated in several neurodevelopmental and neurodegenerative disorders, a multi-modal, longitudinal strategy involving a diverse array of biomarkers and new approaches to statistical modeling are needed to improve early interventions based on the fuller understanding.

Extracellular matrix proteins matrix metallopeptidase 9 (MMP9) and soluble intercellular adhesion molecule 1 (sICAM-1) and correlations with clinical staging in euthymic bipolar disorder

OBJECTIVES

Matrix metallopeptidase 9 (MMP9) and soluble intercellular adhesion molecule 1 (sICAM-1) are both involved in the restructuring of connective tissues. Evidence also implicates MMP9 and sICAM in cardiovascular and neoplastic diseases, where blood levels may be a marker of disease severity or prognosis. In individuals with bipolar disorder (BD), higher risk for cardiovascular illness has been extensively reported.

METHODS

The aim of this investigation was to measure and compare peripheral levels of serum MMP9 and sICAM in adults with euthymic BD and healthy controls (HC). Furthermore, we focussed on correlations with illness severity and metabolic parameters.

RESULTS

MMP9 levels among the BD sample (n = 112) were significantly higher than among the HC (n = 80) (MMP9: F = 9.885, p = 0.002, η(2)  = 0.058) after controlling for confounding factors. Patients with BD in a later, progressive stage of disease showed significantly higher MMP9 as well as sICAM-1 levels compared to patients with BD in an earlier stage of disease (MMP9: F = 5.8, p = 0.018, η(2)  = 0.054; sICAM-1: F = 5.6, p = 0.020, η(2)  = 0.052). Correlation analyses of cognitive measures revealed a negative association between performance on the d2 Test of Attention and MMP9 (r = -0.287, p = 0.018) in the BD sample. Despite the sample being euthymic (i.e., according to conventional criteria) at the time of analysis, we found significant correlations between MMP9 as well as sICAM-1 and subthreshold depressive/hypomanic symptoms.

CONCLUSIONS

A collection of disparate findings herein point to a role of MMP9 and cICAM-1 in the patho-progressive process of BD: the increased levels of serum MMP9 and sICAM-1, the correlation between higher levels of these parameters, progressive stage, and cognitive dysfunction in BD, and the positive correlation with subthreshold symptoms. As sICAM-1 and MMP9 are reliable biomarkers of inflammatory and early atherosclerotic disease, these markers may provide indications of the presence of occult cardiovascular disease in this highly at-risk population.

Adverse effects of antipsychotics on micro-vascular endothelial cells of the human blood-brain barrier

Although the mechanisms of action of antipsychotics (APs) on neuronal function are well understood, very little is known about their effects on cells of the blood-brain barrier (BBB); one function of which is to limit the access of these amphiphilic compounds to the central nervous system. To address this question we have investigated the cytological and functional effects of four APs: chlorpromazine (CLP), haloperidol (HAL), risperidone (RIS) and clozapine (CLZ), at concentrations typical of high therapeutic dosage on a human brain microvascular endothelial cell (HBMEC) model of the BBB. At ~10 µM all four APs impaired the ability of HBMECs to reduce MTT which was followed by decreased Trypan blue exclusion and increased Lactate dehydrogenase release. These effects were associated with oxidative stress which was partly reversed by incubation in 10mM glutathione. At their EC50 concentrations for MTT reduction, all four APs disrupted cellular ultrastructure and morphology. HAL, CPZ and CLZ increased Caspase -3, -8 and -9 activity, chromatin condensation and fragmentation, data indicative of apoptosis. These events were associated with decreased transcytosis of Evans blue and increased transendothelial potential difference and electrical resistance of this BBB model. These findings suggest that at high therapeutic concentrations, CPZ and CLZ are likely to incur cytoxic effects and apoptosis of BBB endothelia with an impairment of barrier functionality. Such events may underlie the aetiology of neuroleptic associated cerebral oedema and neuroleptic malignant syndrome.

Elevated levels of autoantibodies targeting the M1 muscarinic acetylcholine receptor and neurofilament medium in sera from subgroups of patients with schizophrenia

Schizophrenia is a severe debilitating brain disorder with a poorly understood aetiology. Among the diverse aetiological clues lies evidence for immune abnormalities in some individuals. The aim of this study was to investigate the frequency and specificity of autoantibodies directed against the brain in people with schizophrenia. Sera were screened for reactivity against human brain tissue (hippocampus and prefrontal cortex). Neuronal cell body and filamentous patterns of brain tissue staining were observed significantly more frequently in sera from schizophrenia patients (n=30) compared to controls (n=24). Sera that showed a neuronal cell body pattern of staining on hippocampus reacted strongly to an extracellular epitope of the M1 muscarinic acetylcholine receptor (m1AChR) in ELISA. Both cell body staining and elevated m1AChR reactivity correlated with higher symptom scores for poverty of speech. Sera showing a filamentous staining pattern predominantly targeted microfilaments, intermediate filaments or neurofilaments, particularly neurofilament medium (NFM), which is a dopamine receptor interacting protein. By ELISA, there was strongly elevated reactivity against NFM in a subset (15%) of schizophrenia patients (n=101) compared to healthy controls (n=55) or patients with multiple sclerosis (n=32). These results support the hypothesis that neurotransmitter receptors or molecules involved in regulation of neurotransmission are targets of autoantibodies in some people with schizophrenia.

Schizophrenia: redox regulation and volume neurotransmission

Here, we show that volume neurotransmission and the redox property of dopamine, as well as redox-regulated processes at glutamate receptors, can contribute significantly to our understanding of schizophrenia. Namely, volume neurotransmission may play a key role in the development of dysconnectivity between brain regions in schizophrenic patients, which can cause abnormal modulation of NMDA-dependent synaptic plasticity and produce local paroxysms in deafferented neural areas. During synaptic transmission, neuroredox regulations have fundamental functions, which involve the excellent antioxidant properties and nonsynaptic neurotransmission of dopamine. It is possible that the effect of redox-linked volume neurotransmission (diffusion) of dopamine is not as exact as communication by the classical synaptic mechanism, so approaching the study of complex schizophrenic mechanisms from this perspective may be beneficial. However, knowledge of redox signal processes, including the sources and molecular targets of reactive species, is essential for understanding the physiological and pathophysiological signal pathways in cells and the brain, as well as for pharmacological design of various types of new drugs.

Cerebrospinal fluid biomarker candidates of schizophrenia: where do we stand?

Here, we review the cerebrospinal fluid (CSF) candidate markers with regard to their clinical relevance as potential surrogates for disease activity, prognosis assessment, and predictors of treatment response. We searched different online databases such as MEDLINE and EMBASE for studies on schizophrenia and CSF. Initial studies on cerebrospinal fluid in patients with schizophrenia revealed increased brain-blood barrier permeability with elevated total protein content, increased CSF-to-serum ratio for albumin, and intrathecal production of immunoglobulins in subgroups of patients. Analyses of metabolites in CSF suggest alterations within glutamatergic neurotransmission as well as monoamine and cannabinoid metabolism. Decreased levels of brain-derived neurotrophic factor and nerve growth factor in CSF of first-episode patients with schizophrenia reported in recent studies point to a dysregulation of neuroprotective and neurodevelopmental processes. Still, these findings must be considered as non-specific. A more profound characterization of the particular psychopathological profiles, the investigation of patients in the prodromal phase or within the first episode of schizophrenia promoting longitudinal investigations, implementation of different approaches of proteomics, and rigorous adherence to standard procedures based on international CSF guidelines are necessary to improve the quality of CSF studies in schizophrenia, paving the way for identification of syndrome-specific biomarker candidates.

Ferritin levels and their association with regional brain volumes in Tourette's syndrome

OBJECTIVE

A previous small study showed lower serum ferritin levels in subjects with Tourette's syndrome than in healthy subjects. The authors measured peripheral iron indices in a large group of Tourette's syndrome and comparison subjects and explored associations of ferritin levels with regional brain volumes.

METHOD

Ferritin was measured in 107 children and adults (63 Tourette's syndrome, 44 comparison); serum iron was measured in 73 (41 Tourette's syndrome, 32 comparison). Magnetic resonance imaging scans were used to measure volumes of the basal ganglia and cortical gray matter.

RESULTS

Ferritin and serum iron were significantly lower in the Tourette's syndrome subjects, although still within the normal range. No association was found between tic severity and either iron index. In the Tourette's syndrome subjects, ferritin did not correlate significantly with caudate volume but did correlate positively with putamen volume. In the comparison subjects, ferritin correlated inversely with caudate volume but did not correlate significantly with putamen volume. Irrespective of diagnosis, ferritin correlated positively with volumes of the sensorimotor, midtemporal, and subgenual cortices.

CONCLUSIONS

The lower peripheral ferritin and iron levels in persons with Tourette's syndrome are consistent with findings in other movement disorders and suggest that lower iron availability may have a causal role in the pathophysiology of tic disorders. Lower iron stores may contribute to hypoplasia of the caudate and putamen, increasing vulnerability to developing tics or to having more severe tics. Lower iron stores may also contribute to smaller cortical volumes and consequently to reduced inhibitory control of tics.

Immune dysregulation and self‐reactivity in schizophrenia: Do some cases of schizophrenia have an autoimmune basis?

Schizophrenia affects 1% of the world's population, but its cause remains obscure. Numerous theories have been proposed regarding the cause of schizophrenia, ranging from developmental or neurodegenerative processes or neurotransmitter abnormalities to infectious or autoimmune processes. In this review, findings suggestive of immune dysregulation and reactivity to self in patients with schizophrenia are examined with reference to criteria for defining whether or not a human disease is autoimmune in origin. Associations with other autoimmune diseases and particular MHC haplotypes, increased serum levels of autoantibodies, and in vivo and in vitro replication of some of the functional and ultrastructural abnormalities of schizophrenia by transfer of autoantibodies from the sera of patients with schizophrenia suggest that, in some patients at least, autoimmune mechanisms could play a role in the development of disease. Recent findings regarding specific autoimmune responses directed against neurotransmitter receptors in the brain in patients with schizophrenia will also be reviewed.

Characterization of phenothiazine-induced apoptosis in neuroblastoma and glioma cell lines: clinical relevance and possible application for brain-derived tumors

In this study we aimed to (1). screen phenothiazines for cytotoxic activity in glioma, neuroblastoma, and primary mouse brain tissue; and (2). determine the mechanism of the cytotoxic effect (apoptosis, necrosis) and the roles of calmodulin inhibition and sigma receptor modulation. Rat glioma (C6) and human neuroblastoma (SHSY-5Y) cell lines were treated with different phenothiazines. All agents induced a dose-dependent decrease in viability and proliferation, with the highest activity elicited by thioridazine. Sensitivity to thioridazine of glioma and neuroblastoma cells was significantly higher (p < 0.05) than that of primary mouse brain culture (IC50 11.2 and 15.1 microM vs 41.3 microM, respectively). The N-mustard fluphenazine induced significantly lower cytotoxicity in glioma cells, compared to fluphenazine. The sigma receptor selective ligand (+)-SK&F10047 increased viability slightly while combined with fluphenazine; SK&F10047 did not alter fluphenazine activity. Flow cytometry of propidium iodide (PI)-stained glioma cells treated with thioridazine, fluphenazine, or perphenazine (6-50 microM) resulted in a concentration-dependent increase of fragmented DNA up to 94% vs 3% in controls by all agents. Thioridazine (12.5 microM)-treated glioma cells costained with PI and Hoechst 33342 revealed a red fluorescence of fragmented nuclei in treated cells and a blue fluorescence of intact control nuclei. After 4-h exposure to thioridazine (25 and 50 microM), a 25- to 30-fold increase in caspase-3 activity in neuroblastoma cells was noted. Overall, the marked apoptotic effect of phenothiazines in brain-derived cancer cells, and the low sensitivity of primary brain tissue suggest the potential use of selected agents as therapeutic modalities in brain cancer.

Evaluation of the neurotoxic activity of typical and atypical neuroleptics: relevance to iatrogenic extrapyramidal symptoms

Typical neuroleptic therapy often results in extrapyramidal symptoms (EPS) and tardive dyskinesia (TD). Recent reports reveal neurotoxic activity in some neuroleptics. We hypothesized that neurotoxicity might be implicated in EPS. This study aims to evaluate the neurotoxic activity of typical and atypical neuroleptics and to determine the possible role of neurotoxicity in neuroleptic-induced EPS. Perphenazine, haloperidol, clozapine, sulpiride, and risperidone (10-100 microM) were administered, either alone or combined with dopamine, to primary mouse neuronal or intact brain culture and to a human neuroblastoma (NB) cell line (SK-N-SH). Cell viability (measured by neutral red and alamar blue), DNA fragmentation (flow cytometry-NB) were determined. Neuroblastoma: perphenazine, clozapine, and haloperidol (100 microM) decreased viability by 87, 43, and 34% respectively. Sulpiride and risperidone were not toxic. At 10 microM, toxicity decreased markedly. Dopamine (125 microM) potentiated the perphenazine-induced toxicity. Flow cytometry of NB cells treated with perphenazine (2.5-40 microM) showed an increase (perphenazine 20 microM, 40 microM, 48 h) in fragmented DNA (74.7% and 95.0% vs. 8.7% in controls). Lower concentrations increased the G1 phase and decreased S phase in the cell cycle. In primary neurons, perphenazine, haloperidol, and clozapine, but not risperidone and sulpiride, induced a significant neurotoxic effect, which, in intact brain culture, was absent (haloperidol and clozapine) or lowered (perphenazine). Dopamine (0.5 mM) did not modify the effect of the drugs in the primary cultures. Neuroleptics possess differential neurotoxic activity with higher sensitivity of neoplasm tissue (NB compared to primary cultures). The order of toxicity was perphenazine > haloperidol = clozapine:sulpiride and risperidone were not toxic. Neurotoxicity is independent of dopamine and is associated with cell cycle arrest and apoptosis. With the exception of clozapine, neurotoxicity seems relevant to neuroleptic-induced EPS and TD.

Immunohistochemical localization of phosphorylated glial fibrillary acidic protein in the prefrontal cortex and hippocampus from patients with schizophrenia, bipolar disorder, and depression

Increasingly, abnormalities of glial cell function have been implicated in pathological studies of the major mental illnesses (schizophrenia, bipolar disorder, and major depression). In a recent proteomic study, four isoforms of astrocytic glial fibrillary acidic protein (GFAP) were decreased in one or more of these diseases. In the current study, we sought to determine the immunohistochemical localization of phosphorylated GFAP (pGFAP) in the prefrontal cortex and hippocampus and to describe possible disease-related changes in the distribution of pGFAP containing astrocytes. In the prefrontal cortex, interlaminar astrocytes in layer I and stellate astrocytes in layers II and VI were labeled. Labeled cells were also present adjacent to blood vessels in the gyral white matter and in underlying white matter generally. In the hippocampus, labeled cells were present in the polymorphic layer of the dentate gyrus. In the prefrontal cortex, schizophrenia and major depression were characterized by decreased labeling of astrocytes adjacent to blood vessels. There were no significant differences between the diagnostic groups in the other prefrontal layers or in the hippocampus. These results suggest that reduced numbers or functional regulation of pGFAP containing astrocytes occurs in schizophrenia and major depression. The mechanism by which this deficit occurs is not known, but it may adversely effect the regulation of neuronal metabolism, communication, and response to injury.

Decreased levels of soluble intercellular adhesion molecule-1 (sICAM-1) in unmedicated and medicated schizophrenic patients

BACKGROUND

The soluble intercellular adhesion molecule-1 (sICAM-1) is a marker for the activation of the cellular immune system. Since an activation of the immune system has been observed in a part of the schizophrenic patients, we measured the serum levels of soluble ICAM-1 (sICAM-1) in schizophrenic patients and correlated them to the patient's psychopathology.

METHODS

To monitor a possible effect of antipsychotic therapy, 36 schizophrenic patients were examined twice: first without antipsychotic medication immediately after admission to the hospital and then, after clinical improvement before discharge. The results were compared with those of 36 age- and gender-related healthy individuals.

RESULTS

The schizophrenic patients showed significantly decreased serum levels of sICAM-1 at the first examination (248 +/- 95 ng/mL) and at re-examination (266 +/- 95 ng/mL) compared with the comparison group (323 +/- 74 ng/mL). Patients with more pronounced negative symptoms showed higher levels of sICAM-1 at the first examination.

CONCLUSIONS

We conclude that reduced sICAM-1 levels in schizophrenia indicate a reduced activity of the cellular immune system in at least a subgroup of schizophrenic patients.

Free radical scavengers: chemical concepts and clinical relevance

Free radicals are involved in the pathology of many CNS disorders, like Parkinson's disease, Alzheimer's disease, or stroke. This discovery lead to the development of many radical scavengers for the clinical treatment of neurodegenerative diseases. In this review, the different chemical concepts for free radical scavenging will be discussed: nitrons, thiols, iron chelators, phenols, and catechols. Especially catechols, like the naturally occurring flavonols, the synthetic drug nitecapone, or the endogenous catacholamines and their metabolites, are of great interest, as they combine iron chelating with radical scavenging activity. We present data on the radical scvenging activity of dopamine and apomorphine, which prevent lipid peroxidation in rat brain mitochondria and protect PC12 cells against H2O2-toxicity.

Tardive dyskinesia and serum iron indices

BACKGROUND

This study was undertaken to evaluate whether peripheral (serum) markers of iron status are associated with severity of the choreoathetoid movements seen in tardive dyskinesia (TD).

METHODS

Serum iron indices (ferritin, iron, and total iron binding capacity) and fluphenazine levels were measured in a group of 30 male DSM-III diagnosed schizophrenic patients chronically treated with fluphenazine decanoate. The severity of choreoathetoid movements was assessed with the Abnormal Involuntary Movement Scale (AIMS), and akathisia was assessed with the Barnes scale.

RESULTS

A significant positive correlation was observed between AIMS scores and serum ferritin. This relationship remained significant after controlling for age and plasma fluphenazine levels. No significant correlations were observed between serum iron or total iron binding capacity and choreoathetoid movement ratings. There were no significant associations between serum iron indices and akathisia ratings.

CONCLUSIONS

The data suggest that choreoathetoid movements are associated with serum ferritin levels in chronically medicated male schizophrenic patients. This relationship does not seem to be caused by an association of these variable with age or plasma fluphenazine levels. In addition, the relationship seems to be specific, since other iron indices and another extrapyramidal side effect (akathisia) do not demonstrate a similar relationship. In view of reports that antipsychotic medications change normal iron metabolism and increase iron uptake into the brain, the current results could be interpreted to suggest that serum ferritin levels may be a risk factor for TD in patients treated with "classic" antipsychotic medications.

Blood-cerebrospinal fluid barrier impairment as indicator for an immune process in schizophrenia

An impairment of the blood-cerebrospinal fluid barrier (BCB) has repeatedly been described in schizophrenic patients. A BCB impairment can be due to vascular leakage during an inflammatory process, or to neuroleptic treatment. The soluble intercellular adhesion molecule-1 (sICAM-1) has been demonstrated to be a reliable marker for an inflammatory process causing an BCB impairment. To clarify the basis of a BCB impairment in schizophrenic patients, we measured the sICAM-1 levels in CSF of 40 schizophrenic patients. High concentrations of sICAM-1 were found to be related to high concentrations of albumin, IgG and total protein in CSF. A BCB impairment was associated with high levels of sICAM-1. Our data indicate an inflammatory mechanism of BCB impairment in schizophrenics and should enrich the discussion on an expanded immunological diagnosis in schizophrenia.

The potential role of iron chelators in the treatment of Parkinson's disease and related neurological disorders

Neurodegeneration is characterized by a marked accumulation of iron in the affected brain regions. The reason for this is still unknown. In this article we review the available data on the possible involvement of iron and mediated oxidative stress in the aetiology of Parkinson's disease and related disorders. Iron chelators, if they effectively prevent radical formation, have great therapeutic potential against ischaemia/reperfusion, rheumatoid arthritis, and anthracycline toxicity, which are most likely free radical-mediated. The efficacy of the best established chelating drug desferal in neurodegenerative disease is limited due to its high cerebro- and oculotoxicity. New bioactive chelating agents are currently being developed, among them are oxidative stress activatable iron chelators which are most likely less toxic and can flexibly respond to an increase of free radical formation in the cell.

Chlorpromazine stimulatory effect on iron uptake by rat brain synaptosomes

Clinical long-term neuroleptic administration induces extrapyramidal motor side-effects, of which tardive dyskinesia is the most important. Experimentally, dopamine D2 supersensitivity is observed after phenothiazine and butyrophenone treatment. Neuroleptic-induced tardive dyskinesia and D2 modulation have been linked to impaired iron homeostasis in the central nervous system. Increased nonheme iron levels found in the basal ganglia of patients with extrapyramidal symptomology support the connection between iron and neuronal dopaminergic modulation. We now report the effect of chlorpromazine on iron uptake by synaptosomes of rat brain from two different iron donors: [55Fe]citrate and [55Fe]transferrin. Iron uptake from both donors by cortical synaptosomes was stimulated by Ca2+ and enhanced by chlorpromazine in a saturable fashion. Synaptosomes from the striatum also showed increased (60%) iron uptake from [55Fe]citrate in the presence of chlorpromazine. Chlorpromazine stimulated iron uptake by cortical synaptosomes more efficiently than Ca2+, at physiological levels, from both [55Fe]transferrin (50%) and [55Fe]citrate (68%). Calcium potentiated the effect of chloropromazine upon cortical synaptosomal iron uptake from [55Fe]citrate, but had no apparent effect on the uptake from [55Fe]transferrin. Chlorpromazine-stimulated iron uptake from the latter was observed without addition of Ca2+. Moreover, fluorescence measurement of Ca2+ uptake by cortical synaptosomes showed intensified uptake in the presence of 50 microM chlorpromazine (42%). Visible spectral studies of chlorpromazine in the presence of Fe(3+)-citrate and diferric-transferrin did not reveal iron displacement by chlorpromazine from either of the two donors. These data suggest that chlorpromazine may increase iron uptake by neurons, and may be involved in the development of tardive dyskinesia and other extrapyramidal disorders.