Catatonia with GABAA receptor antibodies.

A 22-year-old African woman developed acute behavioural change, against a background of sickle cell disease with strokes requiring a ventriculoperitoneal shunt. She alternated between mutism with prolonged staring and posturing, and a state of agitation with elation and echolalia. Cerebrospinal fluid (CSF) protein was elevated and electroencephalogram showed mild slowing with bitemporal slow and sharp waves. We suspected catatonia secondary to possible autoimmune encephalitis but her condition persisted despite intravenous methylprednisolone. After identifying a positive serum anti-gamma-aminobutyric acid-A (GABAA) antibody, treatment with intravenous immunoglobulin, oral corticosteroids and rituximab led to gradual improvement. Patients with catatonia may show reduced GABAA receptor density and there are two other reports of catatonia with anti-GABAA antibodies. This patient's treatment response supports the antibody's causative role.

Autoimmune encephalitis with GABAA receptor antibodies in a 10-year-old girl.

Recent studies have indicated that some cases of nonparaneoplastic autoimmune encephalitis in children can be caused by a systemic autoimmune disorder that generates autoantibodies to cell membrane proteins. We describe the clinical features of a 10-year-old girl with autoimmune encephalitis with autoantibodies against the GABAA receptor in whom type 1 diabetes mellitus developed during the course of the disease. The diagnosis was based on the progressive course of disease, pleocytosis in the cerebrospinal fluid (CSF), inflammatory changes in the brain and autoantibodies against the GABAA receptor detected in serum (absent in CSF). The treatment of encephalitis included intravenous immunoglobulins, intravenous methylprednisolone, oral prednisolone, cycles of plasmapheresis; this led to temporary remission. Finally, rituximab was applied as a second-line therapy with positive results.

A case of GABAR antibodies in schizophrenia.

BACKGROUND: In the last couple of years, schizophrenia was often discussed as autoimmune disease. Several antibodies were suspected, but so far there has been no proof of Gamma-aminobutyric acid (GABA) receptor antibodies in patients with schizophrenia. CASE PRESENTATION: In this case report we present a 21-year old woman with schizophrenic symptoms, who showed anti-GABAB1 antibodies when screened by a vast recombinant neurology mosaic on Human Embryonic Kidney Cells 293 (HEK293) cells. The young woman presented with various psychotic symptoms as well as speech and motor ataxia, with the neurological signs starting in childhood. CONCLUSION: A hypofunction of the GABAergic system is a possible cause of severe schizophrenic symptoms. Postmortem studies proved this hypothesis by showing dysfunctional GABAergic interneurons in various brain areas. Therefore one should always think of an immune-mediated pathogenesis as well memory impairment and behavioral changes co-occur with frequent seizures.

miR-181a is a negative regulator of GRIA2 in methamphetamine-use disorder.

A previous study reported that the miR-181a level in serum was significantly different between patients with methamphetamine-use disorder and healthy controls and that chronic methamphetamine use down-regulates the expression of miR-181a. Bioinformatic analysis predicted that miR-181a might bind the 3'-UTRs of the mRNA transcripts of the human glutamate receptor genes GRIA2 and GABRA1. In this study, we measured the expression of GRIA2 and GABRA1 in patients with methamphetamine-use disorder. In addition, we examined whether miR-181a down-regulates GRIA2 and GABRA1 in a cell-based assay. We further examined the effects of chronic methamphetamine exposure on the expression of miR-181a, GRIA2 and GABRA1. The results demonstrated that serum GRIA2 is higher in patients with methamphetamine-use disorder than in healthy controls. Dual luciferase reporter assays and a cell-based model of methamphetamine exposure also showed that miR-181a directly regulates expression of GRIA2. This study supports the evidence that miR-181a and the glutamate AMPA receptor gene GRIA2 play a critical role in methamphetamine-use disorder.

Peripartum neuroactive steroid and γ-aminobutyric acid profiles in women at-risk for postpartum depression.

Neuroactive steroids (NAS) are allosteric modulators of the γ-aminobutyric acid (GABA) system. NAS and GABA are implicated in depression. The peripartum period involves physiologic changes in NAS which may be associated with peripartum depression and anxiety. We measured peripartum plasma NAS and GABA in healthy comparison subjects (HCS) and those at-risk for postpartum depression (AR-PPD) due to current mild depressive or anxiety symptoms or a history of depression. We evaluated 56 peripartum medication-free subjects. We measured symptoms with the Hamilton Depression Rating Scale (HAM-D17), Hamilton Anxiety Rating Scale (HAM-A) and Spielberger State-Trait Anxiety Inventory-State (STAI-S). Plasma NAS and GABA were quantified by liquid chromatography-mass spectrometry. We examined the associations between longitudinal changes in NAS, GABA and depressive and anxiety symptoms using generalized estimating equation methods. Peripartum GABA concentration was 1.9±0.7ng/mL (p=0.004) lower and progesterone and pregnanolone were 15.8±7.5 (p=0.04) and 1.5±0.7ng/mL (p=0.03) higher in AR-PPD versus HCS, respectively. HAM-D17 was negatively associated with GABA (ß=-0.14±0.05, p=0.01) and positively associated with pregnanolone (ß=0.16±0.06, p=0.01). STAI-S was positively associated with pregnanolone (ß=0.11±0.04, p=0.004), allopregnanolone (ß=0.13±0.05, p=0.006) and pregnenolone (ß=0.02±0.01, p=0.04). HAM-A was negatively associated with GABA (ß=-0.12±0.04, p=0.004) and positively associated with pregnanolone (ß=0.11±0.05, p=0.05). Altered peripartum NAS and GABA profiles in AR-PPD women suggest that their interaction may play an important role in the pathophysiology of peripartum depression and anxiety.

Increased serum levels of C21 steroids in female patients with multiple sclerosis.

Multiple sclerosis (MS) is one of the most common neurological diseases. This neurodegenerative autoimmune disease manifests as inflammatory and demyelinating impairment of the central nervous system (CNS). Although some studies demonstrated associations between altered steroidogenesis and pathophysiology of MS as well as the importance of steroids in the pathophysiology of MS, the knowledge concerning the steroid metabolome in female patients is limited. Hence, 51 steroids and steroid polar conjugates were measured in the serum of 12 women with MS, untreated with steroids and 6 age-corresponding female controls with the use of gas chromatography - mass spectrometry (GC-MS). The data were processed using age adjusted ANCOVA, receiver operating characteristics (ROC) analysis and orthogonal projections to latent structures (OPLS). Our data show higher levels of circulating C21 steroids including steroid modulators of ionotropic type A gamma-aminobutyric acid (GABA A) receptors and glutamate receptors. Furthermore, the levels of GABAergic androsterone and 5-androsten-3beta,7alpha,17beta-triol were also higher in the female MS patients. In conclusion, the data demonstrate higher levels of circulating C21 steroids and their polar conjugates and some bioactive C19 steroids in women with MS, which may influence neuronal activity and affect the balance between neuroprotection and excitotoxicity.

Increased plasma levels of endozepines, endogenous ligands of benzodiazepine receptors, during systemic inflammation: a prospective observational study.

INTRODUCTION: Recent work has shown that benzodiazepines interact with the immune system and exhibit anti-inflammatory effects. By using in vitro models, researchers in several studies have shown that the peptidergic endogenous ligands of benzodiazepine receptors, named endozepines, are involved in the immune response. All endozepines identified so far derive from diazepam-binding inhibitor (DBI), which generates several biologically active fragments. The aim of the present study was to measure plasma levels of DBI-like immunoreactivity (DBI-LI) in a rat model of sepsis and in patients with systemic inflammation from septic or non-septic origin. METHODS: Cecal ligation and puncture (CLP) or sham surgery was performed in rats. Blood samples were taken from animals, patients hospitalized for digestive surgery with inflammatory diseases, and healthy volunteers. Measurements of plasma DBI-related peptides were carried out by radioimmunoassay in animal and human samples. RESULTS: In the rats, CLP provoked an increase of plasma DBI-LI (+37%) 6 hours postsurgery. In humans, DBI-LI levels were significantly higher in the systemic inflammation group than in the healthy volunteer group (48.6 (32.7 to 77.7) pg/ml versus 11.1 (5.9 to 35.3) pg/ml, P < .001). We found a positive correlation between endozepine levels and Acute Physiology and Chronic Health Evaluation II score (r s = 0.33 (0.026 to 0.58), P < 0.05) and tumor necrosis factor α levels (r s = 0.43 (0.14 to 0.65), P < 0.01). The area under the receiver operating characteristic curve for endozepines was 0.842 (95% CI (0.717 to 0.966), P < 0.0001) for discriminating patients with inflammation from healthy volunteers. CONCLUSIONS: Endozepines might be involved in the inflammatory response in patients with systemic inflammation.

Evaluation of neurotransmitter receptor gene expression identifies GABA receptor changes: a follow-up study in antipsychotic-naïve patients with first-episode psychosis.

A study of the gene expression levels in the blood of individuals with schizophrenia in the beginning of the disease, such as first-episode psychosis (FEP), is useful to detect gene expression changes in this disorder in response to treatment. Although a large number of genetic studies on schizophrenia have been conducted, little is known about the effects of antipsychotic treatment on gene expression. The aim of the present study was to examine differences in the gene expression in the blood of antipsychotic-naïve FEP patients before and after risperidone treatment (N = 44) and also to verify the correlation with treatment response. In addition, we determined the correlations between differentially expressed genes and clinical variables. The expression of 40 neurotransmitter and neurodevelopment-associated genes was assessed using the RT2 Profiler PCR Array. The results indicated that the GABRR2 gene was downregulated after risperidone treatment, but no genes were associated with response to treatment and clinical variables after Bonferroni correction. GABRR2 downregulation after treatment can both suggest an effect of risperidone treatment or processes related to disease progression, either not necessarily associated with the improvement of symptoms. Despite this change was observed in blood, this decrease in GABRR2 mRNA levels might be an effect of changes in GABA concentrations or other systems interplay consequently to D2 blockage induced by risperidone, for example. Thus, it is important to consider that antipsychotics or the progression of psychotic disorders might interfere with gene expression.

Intrahepatic cholestasis of pregnancy: new insights into its pathogenesis.

AIM: To search a specific gene expression profile in women with intrahepatic cholestasis of pregnancy (ICP) and to evaluate the maternal and foetal outcome. METHODS: We consecutively enrolled 12 women with ICP and 12 healthy pregnant controls. The gene expression profile was assayed with the microarray technique including a panel of 5541 human genes. Microarray data were validated by real-time PCR technique. RESULTS: Caesarean delivery was performed in eight patients with ICP versus three controls (p = 0.05). ICP women delivered at earlier gestational age than control (p < 0.001). Foetal distress was recorded in two babies, but we failed to find any correlation between bile salt concentration and foetal distress. Twenty genes potentially correlated with ICP were found differentially expressed (p < 0.05). Among these, three belong to genetic classes involved in pathogenic mechanisms of ICP: (1) pathophysiology of pruritus (GABRA2, cases versus controls = 2, upregulated gene); (2) lipid metabolism and bile composition (HLPT, cases versus controls = 0.6, down-regulated gene) and (3) protein trafficking and cytoskeleton arrangement (KIFC3, cases versus controls = 0.5, down-regulated gene). CONCLUSIONS: Different gene expression may contribute to the complex pathogenesis of ICP. An upregulation of GABRA2 receptor may indicate that GABA may play a role in the pathogenesis of pruritus in this condition.

Erythrocyte peripheral type benzodiazepine receptor/voltage-dependent anion channels are upregulated by Plasmodium falciparum.

Plasmodium falciparum relies on anion channels activated in the erythrocyte membrane to ensure the transport of nutrients and waste products necessary for its replication and survival after invasion. The molecular identity of these anion channels, termed "new permeability pathways" is unknown, but their currents correspond to up-regulation of endogenous channels displaying complex gating and kinetics similar to those of ligand-gated channels. This report demonstrates that a peripheral-type benzodiazepine receptor, including the voltage dependent anion channel, is present in the human erythrocyte membrane. This receptor mediates the maxi-anion currents previously described in the erythrocyte membrane. Ligands that block this peripheral-type benzodiazepine receptor reduce membrane transport and conductance in P falciparum-infected erythrocytes. These ligands also inhibit in vitro intraerythrocytic growth of P falciparum. These data support the hypothesis that dormant peripheral-type benzodiazepine receptors become the "new permeability pathways" in infected erythrocytes after up-regulation by P falciparum. These channels are obvious targets for selective inhibition in anti-malarial therapies, as well as potential routes for drug delivery in pharmacologic applications.

In vivo binding of protoporphyrin IX to rat translocator protein imaged with positron emission tomography.

In vitro experiments have shown that protoporphyrin IX (PPIX) binds to the translocator protein 18 kDa (TSPO), which transports cholesterol across the outer mitochondrial membrane. The purpose of this study was to examine whether binding of PPIX to TSPO can also be detected in vivo using positron emission tomography and [(11)C]PBR28, a radioligand that binds with high affinity and selectivity to TSPO. Rats were injected with a high dose of 5-aminolevulinic acid (ALA, 200 mg/kg i.v.), which is a precursor for PPIX. ALA-pretreatment significantly decreased the uptake of [(11)C]PBR28 in TSPO-rich organs such as heart, kidneys, lungs, parotid glands, and spleen by 57-80%. As a control experiment, injection of a receptor saturating does of PK 11195, which is selective for TSPO, produced a pattern of displacement similar to that after ALA but with greater magnitude (88-97%). This study provides the first evidence that PPIX binds in vivo to TSPO. Although PPIX at physiological concentrations would likely occupy an insignificant percentage of TSPOs, it does reach high-enough concentrations in porphyria to occupy and have pharmacological effects via this target.

Neuroligand binding endophenotypes in blood cells distinguish two subsets of borderline personality disorder patients.

Neurotransmitter ligand binding in blood cells was assessed in borderline personality disorder (BDP) patients, testing the possibility that different biochemical endophenotypes might lie beneath a specific clinical presentation. The density of peripheral benzodiazepine receptors (PBR) and serotonin transporters were assessed in peripheral blood mononuclear cells (PBMC) and platelets, respectively, showing a decrease of both parameters. Moreover, a further significant decrease of PBR in PBMC was shown for those patients with a depressive trait. Further confirmation of the presence of different molecular endophenotypes underlying the dissimilar clinical presentations in BPD may advance our possibility of successfully treating these patients.

Assessment of GABAA benzodiazepine receptor (GBzR) sensitivity in patients with alcohol dependence.

AIM: The aim of this study was to measure GABAA benzodiazepine receptor (GBzR) sensitivity in alcohol-dependent patients and compare with matched non-dependent drinkers. METHODS: Nine abstinent alcohol-dependent male patients, age matched with nine male non-dependent social drinkers, received an intravenous infusion of midazolam. Objective (saccadic eye movement slowing) and subjective (visual analogue scales) measurements were recorded at 15-min intervals for 2 h. RESULTS: There were no differences in objective or subjective measures. CONCLUSIONS: Our hypothesis that patients with alcohol dependence would have less slowing of their eye movements in response to this challenge, reflecting reduced GBzR sensitivity, was not confirmed. The reasons for this could mean that GBzR function returns to normal with abstinence, or that this paradigm is unable to measure the subtle subtype-specific changes in GBzR sensitivity that occur following dependent alcohol use.

[Platelet peripheral benzodiazepine receptors in alcoholism].

The peripheral-type benzodiazepine receptor (PBR) is an transmembrane protein, distinct pharmacologically, structurally and functionally from the central-type benzodiazepine receptor. The kinetic binding parameters of the specific PBR ligand, the PK11195, have been evaluated in platelets from 36 male alcoholic patients in relation to 19 healthy sex-matched controls. A significant increase of mean value of platelet PBR density was observed in patients as compared to the controls (4733 +/- 379 and 3358 +/- 242 fmol/mg proteins, p < 0.005). There are no statistically significant changes in the receptor affinity values in the group of patients.

Pharmacokinetics of the active metabolites of ethyl loflazepate in elderly patients who died of asphyxia associated with benzodiazepine-related toxicity.

We determined the pharmacokinetics of ethyl loflazepate (Lof) in elderly patients who died of benzodiazepine-related toxicity. Three elderly patients with body mass indexes of less than 17 kg/m2 died of asphyxia after having taken maintenance doses of Lof for 2 to 3 weeks. We measured serum concentrations of the active metabolites of Lof using gas chromatography-mass spectrometry and a benzodiazepine receptor assay to determine the pharmacokinetics of each. On admission, the serum concentrations of the active metabolites of Lof ([Lofl) were 256 ng/mL, 425 ng/mL, and 177 ng/mL in cases 1, 2, and 3, respectively. Serum benzodiazepine-receptor binding activities, expressed as diazepam equivalent concentrations ([Bz]), were 1800 ng/mL, 2200 ng/mL, and 1500 ng/mL. The T1/2(beta) of [Lof] were 124 and 121 h in cases 1 and 2 and the T1/2(beta) of [Bz] were 75 and 87 h. The distribution volume in the elderly was reduced due to a small lipid compartment, and total drug clearance was decreased due to the decline in liver and kidney function. These changes did not prolong T1/2(beta) but did increase plasma concentrations of active metabolites, especially in case 2, and a slight decrease in protein binding increased the amount of free active metabolites greatly.

GABA(A) receptor active steroids are altered in epilepsy patients with tuberous sclerosis.

BACKGROUND: The neuroactive steroid 3alpha, 5alpha-tetrahydroprogesterone is the most potent endogenous positive modulator of gamma-amino-butyric acid (GABA)(A) receptors. There is evidence for a relation between neuroactive steroids and seizure susceptibility. OBJECTIVE: To evaluate the putative role of counteregulator neuroactive steroids in the occurrence of seizures in patients with tuberous sclerosis. METHODS: Plasma concentrations of the enantiomers 3alpha, 5alpha- and 3alpha, 5beta-tetrahydroprogesterone (3alpha(s)-THP), which are positive modulators of GABA(A) receptors, were measured in 18 patients, along with their endogenous functional antagonists 3beta, 5alpha- and 3beta, 5beta-THP (3beta(s)-THP), to assess their possible modification compared with control subjects. Neuroactive steroids were assayed using a highly sensitive and specific gas chromatographic/mass spectrometric method. RESULTS: In the tuberous sclerosis patients with poorly controlled seizures, there was a significantly lower 3alpha(s)/3beta(s)-THP ratio than in seizure-free patients or control subjects. CONCLUSIONS: The reduced 3alpha(s)/3beta(s)-THP ratio may decrease GABAergic tone, contributing to the appearance of seizures in tuberous sclerosis patients with epilepsy.

Peripheral markers of the gamma-aminobutyric acid (GABA)ergic system in Angelman's syndrome.

It has recently been demonstrated that patients with Angelman's syndrome who exhibited a deletion on cytogenetic tests show more severe clinical pictures with drug-resistant epilepsy than patients with Angelman's syndrome not carrying the deletion. To verify if this difference in clinical severity can be attributed to genes for the three gamma-aminobutyric acid (GABA)A receptor subunits (GABRB3, GABRA5, GABRG3) located in the deleted region, a possible modification of peripheral markers of the GABAergic system was investigated in 12 subjects with Angelman's syndrome and 20 age-matched subjects (8 with idiopathic epilepsy and 12 not affected by neurologic diseases). The results confirmed a more severe clinical picture, and epilepsy syndrome in particular, in Angelman's syndrome patients with deletions versus patients without deletions. In contrast, biochemical study (based on dosage of plasma levels of GABA and diazepam binding inhibitor, an endogenous ligand of GABAA and peripheral benzodiazepine receptors, showed contradictory results: patients with Angelman's syndrome showed significantly higher levels of GABA and diazepam binding inhibitor than patients without neurologic impairment but significantly lower levels than epileptic controls.

Effects of gonadal steroids on peripheral benzodiazepine receptor density in women with PMS and controls.

BACKGROUND: GABA receptor-modifying neurosteroids may play a role in premenstrual syndrome (PMS). The peripheral benzodiazepine receptor (PBR) both regulates the formation of neurosteroids and is, in animals, regulated by ovarian steroids. Alterations in PBR density have been observed in association with several psychiatric disorders. METHODS: We examined the effects of gonadal steroids on lymphocytic PBR density in nine women with prospectively confirmed PMS and nine controls. PBR densities were measured during three pharmacologically controlled conditions: gonadotropin releasing hormone agonist (Lupron)-induced hypogonadism, Lupron plus estradiol, and Lupron plus progesterone replacement. Blood samples were obtained after six weeks of Lupron alone and after 3-4 weeks of estradiol and progesterone replacement. RESULTS: No significant hormone state-related changes in PBR density were observed (ANOVA-R: phase-F(2,32)=1.5, P=0.2). Despite mood symptom development in the subjects with PMS, PBR density did not differ in women with PMS compared to controls across hormonal states (ANOVA-R: F(1,16)=0.6, P=0.4). CONCLUSIONS: PBR densities are not altered in women with PMS and are not changed significantly by selective gonadal steroid administration. Changes in PBR density would not appear to underlie the differential sensitivity to the mood destabilizing effects of ovarian steroids in PMS.