The renin secretion profile under the influence of sleep deprivation and the neuropeptides CRH and GHRH

It is already known that during normal sleep plasma renin activity (PRA) shows oscillations with decreases during rapid-eye-movement (REM) sleep and increases during non-REM (NREM) sleep. We also know that renin correlates positively with slow-wave sleep (SWS). Sleep deprivation is known to enhance significantly SWS and slow wave activity (SWA, known as δ power). Based on these findings we addressed the question whether and to which extent sleep deprivation may affect the synchronization found between PRA and REM sleep during normal sleep and whether this synchronization is affected by other sleep regulating factors. To investigate these questions we compared sleep EEG and sleep-related free renin levels in 48 normal women and men 19-69 years old between nights before and after 40 h of sleep deprivation. During the recovery night, four bolus injections of either GHRH, CRH or placebo were injected via long catheter around sleep onset. When compared to baseline after each of the treatments SWS, SWA and renin levels increased. The characteristical oscillation profiles of renin during normal sleep were also preserved after sleep deprivation. Similar to normal sleep our data support also a distinct link between nocturnal renin secretion and SWS after sleep deprivation and that independent of the applied treatments.

Depression, comorbidities and the TNF-α system

Depression has frequently been reported to be associated with other physical diseases and changes in the cytokine system. We aimed to investigate associations between a medical history of depression, its comorbidities and cytokine plasma levels in the Bavarian Nutrition Survey II (BVS II) study sample and in patients suffering from an acute depressive episode.

The BVS II is a representative study of the Bavarian population aged 13–80 years. The disease history of its 1050 participants was assessed through face-to-face interviews. A sub-sample of 568 subjects and 62 additional acutely depressed inpatients of the Max Planck Institute of Psychiatry participated in anthropometric measurements and blood sampling. Tumor necrosis factor-α (TNF-α) and soluble TNF receptor (sTNF-R) p55 and sTNF-R p75 plasma levels were measured using enzyme-linked immunosorbent assays.

A history of depression was associated with a higher incidence of high blood pressure, peptic ulcer, dyslipoproteinemia, osteoporosis, allergic skin rash, atopic eczema and thyroid disease.

Within the BVS II sample, participants with a history of depression differed from subjects who had never had depression with regard to sTNF-R p55 and sTNF-R p75 levels even when controlling for age, BMI and smoking status. Acutely depressed inpatients showed even higher levels of sTNF-R p55 and sTNF-R p75 than subjects in the normal population. TNF-α levels were also significantly elevated in acutely depressed patients.

These results confirm earlier studies regarding the comorbidities of depression and support the hypothesis that activation of the TNF-α system may contribute to the development of a depressive disorder.

Sleep after intranasal progesterone vs. zolpidem and placebo in postmenopausal women - A randomized, double-blind cross over study

CONTEXT

The loss of progesterone during menopause is linked to sleep complaints of the affected women. Previously we demonstrated sleep promoting effects of oral progesterone replacement in postmenopausal women. The oral administration of progesterone, however, is compromised by individual differences in bioavailability and metabolism of the steroid.

OBJECTIVE

We compared the sleep-endocrine effects after intranasal progesterone (MPP22), zolpidem and placebo in healthy postmenopausal women.

DESIGN

This was a randomized double-blind cross-over study.

SETTING

German monocentric study PARTICIPANTS: Participants were 12 healthy postmenopausal women.

INTERVENTIONS

Subjects received in randomized order four treatments, 2 doses of intranasal progesterone (4.5 mg and 9 mg of MPP22), 10 mg of zolpidem and placebo.

OUTCOME MEASURES

Main outcome were conventional and quantitative sleep-EEG variables. Secondary outcomes were the subjective sleep variables and the sleep related concentrations of cortisol, growth hormone (GH), melatonin and progesterone.

RESULTS

Sleep promoting effects were found after the higher dosage of MPP22 and after zolpidem. Zolpidem prompted benzodiazepine-like effects on quantitative sleep EEG as expected, whereas no such changes were found after the two dosages of MP22. Nocturnal progesterone levels increased after 9.0 mg MPP22. No other changes of hormone secretion were found.

CONCLUSIONS

Our study shows sleep promoting effects after intranasal progesterone. The spectral signature of intranasal progesterone did not resemble the sleep-EEG alterations induced by GABA active compounds. Progesterone levels were elevated after 9.0 mg MPP22. No other endocrine effects were observed.

Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology: Update 2017

Therapeutic drug monitoring (TDM) is the quantification and interpretation of drug concentrations in blood to optimize pharmacotherapy. It considers the interindividual variability of pharmacokinetics and thus enables personalized pharmacotherapy. In psychiatry and neurology, patient populations that may particularly benefit from TDM are children and adolescents, pregnant women, elderly patients, individuals with intellectual disabilities, patients with substance abuse disorders, forensic psychiatric patients or patients with known or suspected pharmacokinetic abnormalities. Non-response at therapeutic doses, uncertain drug adherence, suboptimal tolerability, or pharmacokinetic drug-drug interactions are typical indications for TDM. However, the potential benefits of TDM to optimize pharmacotherapy can only be obtained if the method is adequately integrated in the clinical treatment process. To supply treating physicians and laboratories with valid information on TDM, the TDM task force of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued their first guidelines for TDM in psychiatry in 2004. After an update in 2011, it was time for the next update. Following the new guidelines holds the potential to improve neuropsychopharmacotherapy, accelerate the recovery of many patients, and reduce health care costs.

Corticotropin-releasing hormone induces depression-like changes of sleep electroencephalogram in healthy women

We reported previously that repetitive intravenous injections of corticotropin-releasing hormone (CRH) around sleep onset prompt depression-like changes in certain sleep and endocrine activity parameters (e.g. decrease of slow-wave sleep during the second half of the night, blunted growth hormone peak, elevated cortisol concentration during the first half of the night). Furthermore a sexual dimorphism of the sleep-endocrine effects of the hormones growth hormone-releasing hormone and ghrelin was observed. In the present placebo-controlled study we investigated the effect of pulsatile administration of 4×50μg CRH on sleep electroencephalogram (EEG) and nocturnal cortisol and GH concentration in young healthy women. After CRH compared to placebo, intermittent wakefulness increased during the total night and the sleep efficiency index decreased. During the first third of the night, REM sleep and stage 2 sleep increased and sleep stage 3 decreased. Cortisol concentration was elevated throughout the night and during the first and second third of the night. GH secretion remained unchanged. Our data suggest that after CRH some sleep and endocrine activity parameters show also depression-like changes in healthy women. These changes are more distinct in women than in men.

[Strategies for cerebrospinal fluid analysis - Integrated results report]

Cerebrospinal fluid (CSF) analysis requires a combined assessment of all individual test findings in an integrated total report in order to achieve a reliable and specific diagnostic conclusion. Such a standard assessment strategy allows the identification of disease-typical result patterns and plausibility checks to avoid analytical errors. The integrated total report consists of 1) a basic CSF program with cytological and protein chemical parameters, 2) an expanded CSF program with special parameters for detection of pathogens and markers of neurodegeneration and 3) a final contextual interpretation considering methodological and clinical aspects.

Ghrelin modulates encoding-related brain function without enhancing memory formation in humans

Ghrelin regulates energy homeostasis in various species and enhances memory in rodent models. In humans, the role of ghrelin in cognitive processes has yet to be characterized. Here we show in a double-blind randomized crossover design that acute administration of ghrelin alters encoding-related brain activity, however does not enhance memory formation in humans. Twenty-one healthy young male participants had to memorize food- and non-food-related words presented on a background of a virtual navigational route while undergoing fMRI recordings. After acute ghrelin administration, we observed decreased post-encoding resting state fMRI connectivity between the caudate nucleus and the insula, amygdala, and orbitofrontal cortex. In addition, brain activity related to subsequent memory performance was modulated by ghrelin. On the next day, however, no differences were found in free word recall or cued location-word association recall between conditions; and ghrelin's effects on brain activity or functional connectivity were unrelated to memory performance. Further, ghrelin had no effect on a cognitive test battery comprising tests for working memory, fluid reasoning, creativity, mental speed, and attention. In conclusion, in contrast to studies with animal models, we did not find any evidence for the potential of ghrelin acting as a short-term cognitive enhancer in humans.

RNA expression profiling in depressed patients suggests retinoid-related orphan receptor alpha as a biomarker for antidepressant response

Response to antidepressant treatment is highly variable with some patients responding within a few weeks, whereas others have to wait for months until the onset of clinical effects. Gene expression profiling may be a tool to identify markers of antidepressant treatment response and new potential drug targets. In a first step, we selected 12 male, age- and severity-matched pairs of remitters and nonresponders, and analyzed expression profiles in peripheral blood at admission and after 2 and 5 weeks of treatment using Illumina expression arrays. We identified 127 transcripts significantly associated with treatment response with a minimal P-value of 9.41 × 10(-)(4) (false discovery rate-corrected). Analysis of selected transcripts in an independent replication sample of 142 depressed inpatients confirmed that lower expression of retinoid-related orphan receptor alpha (RORa, P=6.23 × 10(-4)), germinal center expressed transcript 2 (GCET2, P=2.08 × 10(-2)) and chitinase 3-like protein 2 (CHI3L2, P=4.45 × 10(-2)) on admission were associated with beneficial treatment response. In addition, leukocyte-specific protein 1 (LSP1) significantly decreased after 5 weeks of treatment in responders (P=2.91 × 10(-2)). Additional genetic, in vivo stress responsitivity data and murine gene expression findings corroborate our finding of RORa as a transcriptional marker of antidepressant response. In summary, using a genome-wide transcriptomics approach and subsequent validation studies, we identified several transcripts including the circadian gene transcript RORa that may serve as biomarkers indicating antidepressant treatment response.

The effect of the ANKK1/DRD2 Taq1A polymorphism on weight changes of dopaminergic treatment in prolactinomas

Treatment with dopamine agonists in patients with prolactinomas has been associated with weight loss in short term studies. However, long-term studies on weight changes are lacking. Taq1A is a restriction fragment length polymorphism considered as a gene marker for the DRD2 gene. The presence of at least one A1 allele is linked to reduced brain dopaminergic activity due to reduced receptor binding and lower density of the dopamine 2 receptor. We aimed at testing the hypothesis that the dopaminergic treatment in prolactinoma patients leads to sustained weight loss and that the presence of diminished weight loss response under dopamine agonists is associated with the minor A1 allele of Taq1A.We included n = 44 patients (17 male and 27 female, 26 macroadenomas and 18 microadenomas) with prolactinomas treated with dopamine agonists. Outcome measures were weight and body mass index (BMI) change under dopaminergic treatment after 2 years with regard to Taq1A status and sex. We observed that the dopaminergic treatment leads to a significant mean weight loss of 3.1 ± 6.25 kg after 2 years. Regarding Taq1A polymorphisms, 21 patients were carriers of at least one A1 allele and 23 patients had a genotype of A2/A2. However, the presence of the A1 allele was neither associated with the mean BMI at baseline nor with an altered weight loss response under dopamine agonist therapy. Our results implicate that the dopaminergic treatment leads to a sustained weight loss in patients with prolactinomas after 2 years. However, there was no association to the A1 allele of Taq1A, observation that needs to be analysed in larger cohorts.

Transcriptional regulation is insufficient to explain substrate-induced flux changes in Bacillus subtilis

Regulation of enzyme expression is one key mechanism by which cells control their metabolic programs. In this work, a quantitative analysis of metabolism in a model bacterium under different conditions shows that expression alone cannot explain the majority of the observed metabolic changes.

Most enzymes are indeed highly expressed in conditions where they are more active.

Quantitatively, however, the observed changes in expression between conditions do not match the changes in activity for most enzymes.

A good quantitative match is only observed for enzymes involved in the TCA cycle.

Metabolomics reveals that increased substrate availability explains only a few instances of changes in activity.

One of the key ways in which microbes are thought to regulate their metabolism is by modulating the availability of enzymes through transcriptional regulation. However, the limited success of efforts to manipulate metabolic fluxes by rewiring the transcriptional network has cast doubt on the idea that transcript abundance controls metabolic fluxes. In this study, we investigate control of metabolic flux in the model bacterium Bacillus subtilis by quantifying fluxes, transcripts, and metabolites in eight metabolic states enforced by different environmental conditions. We find that most enzymes whose flux switches between on and off states, such as those involved in substrate uptake, exhibit large corresponding transcriptional changes. However, for the majority of enzymes in central metabolism, enzyme concentrations were insufficient to explain the observed fluxes—only for a number of reactions in the tricarboxylic acid cycle were enzyme changes approximately proportional to flux changes. Surprisingly, substrate changes revealed by metabolomics were also insufficient to explain observed fluxes, leaving a large role for allosteric regulation and enzyme modification in the control of metabolic fluxes.

Genetic variation in FKBP5 associated with the extent of stress hormone dysregulation in major depression

The FK506 binding protein 51 or FKBP5 has been implicated in the regulation of glucocorticoid receptor (GR) sensitivity, and genetic variants in this gene have been associated with mood and anxiety disorders. GR resistance and associated stress hormone dysregulation are among the most robust biological findings in major depression, the extent of which may be moderated by FKBP5 polymorphisms. FKBP5 mRNA expression in peripheral blood cells (baseline and following in vivo GR stimulation with 1.5 mg dexamethasone p.o.) was analyzed together with plasma cortisol, ACTH, dexamethasone levels and the FKBP5 polymorphism rs1360780 in 68 depressed patients and 87 healthy controls. We observed a significant (P = 0.02) interaction between disease status and FKBP5 risk allele carrier status (minor allele T) on GR-stimulated FKBP5 mRNA expression. Patients carrying the risk T allele, but not the CC genotype, showed a reduced induction of FKBP5 mRNA. This FKBP5 polymorphism by disease status interaction was paralleled by the extent of plasma cortisol and ACTH suppression following dexamethasone administration, with a reduced suppression only observed in depressed patients carrying the T allele. Only depressed patients carrying the FKBP5 rs1360780 risk allele showed significant GR resistance compared with healthy controls, as measured by dexamethasone-induced FKBP5 mRNA induction in peripheral blood cells and suppression of plasma cortisol and ACTH concentrations. This finding suggests that endocrine alterations in depressed patients are determined by genetic variants and may allow identification of specific subgroups.

Large genomic aberrations detected by SNP array are independent prognosticators of a shorter time to first treatment in chronic lymphocytic leukemia patients with normal FISH

BACKGROUND

Genomic complexity can predict the clinical course of patients affected by chronic lymphocytic leukemia (CLL) with a normal FISH. However, large studies are still lacking. Here, we analyzed a large series of CLL patients and also carried out the so far largest comparison of FISH versus single-nucleotide polymorphism (SNP) array in this disease.

PATIENTS AND METHODS

SNP-array data were derived from a previously reported dataset.

RESULTS

Seventy-seven of 329 CLL patients (23%) presented with a normal FISH. At least one large (>5 Mb) genomic aberration was detected by SNP array in 17 of 77 patients (22%); this finding significantly affected TTT. There was no correlation with the presence of TP53 mutations. In multivariate analysis, including age, Binet stage, IGHV genes mutational status and large genomic lesion, the latter three factors emerged as independent prognosticators. The concordance between FISH and SNP array varied between 84 and 97%, depending on the specific genomic locus investigated.

CONCLUSIONS

SNP array detected additional large genomic aberrations not covered by the standard FISH panel predicting the outcome of CLL patients.

Cerebrospinal fluid parameters of B cell-related activity in patients with active disease during natalizumab therapy

Recently, the disappearance of oligoclonal bands (OCBs) from the cerebrospinal fluid (CSF) of a few natalizumab-treated patients with multiple sclerosis (MS) has been reported. This is interesting since CSF-restricted OCB are believed to persist in MS. We pooled CSF data from 14 MS centers to obtain an adequate sample size for investigating the suspected changes in central nervous system (CNS)-restricted humoral immune activities in the context of natalizumab therapy. In a retrospective chart analysis, CSF parameters of blood-CSF barrier integrity and intrathecal IgG production from 73 natalizumab-treated MS patients requiring a diagnostic puncture for exclusion of progressive multifocal leukoencephalopathy were compared with CSF data obtained earlier in the course of disease before natalizumab therapy. At the time of repeat lumbar puncture, local IgG production (according to Reibergram) was significantly reduced (p < 0.0001) and OCB had disappeared in 16% of the patients. We therefore conclude that natalizumab therapy interferes with intrathecal antibody production at least in a significant number of patients.

Convergent animal and human evidence suggests the activin/inhibin pathway to be involved in antidepressant response

Despite the overt need for improved treatment modalities in depression, efforts to develop conceptually novel antidepressants have been relatively unsuccessful so far. Here we present a translational approach combining results from hypothesis-free animal experiments with data from a genetic association study in depression. Comparing genes regulated by chronic paroxetine treatment in the mouse hippocampus with genes showing nominally significant association with antidepressant treatment response in two pharmacogenetic studies, the activin pathway was the only one to show this dual pattern of association and therefore selected as a candidate. We examined the regulation of activin A and activin receptor type IA mRNA following antidepressant treatment. We investigated the effects of stereotaxic infusion of activin into the hippocampus and the amygdala in a behavioural model of depression. To analyse whether variants in genes in the activin signalling pathway predict antidepressant treatment response, we performed a human genetic association study. Significant changes in the expression of genes in the activin signalling pathway were observed following 1 and 4 weeks of treatment. Injection of activin A into the hippocampus exerts acute antidepressant-like effects. Polymorphisms in the betaglycan gene, a co-receptor mediating functional antagonism of activin signalling, significantly predict treatment outcome in our system-wide pharmacogenetics study in depression. We provide convergent evidence from mouse and human data that genes in the activin signalling pathway are promising novel candidates involved in the neurobiogical mechanisms underlying antidepressant mechanisms of action. Further, our data suggest this pathway to be a target for more rapid-acting antidepressants in the future.

Polymorphisms of the drug transporter gene ABCB1 predict side effects of treatment with cabergoline in patients with PRL adenomas

INTRODUCTION

Treatment with dopamine agonists in patients with prolactin (PRL) adenomas and Parkinson's disease is associated with central side effects. Central side effects may depend on a substance's ability to pass the blood-brain barrier, which can be actively controlled by transporter molecules such as the P-glycoprotein (P-gp) encoded by the ABCB1 gene.

MATERIALS AND METHODS

We aimed to determine whether cabergoline is transported by the P-gp and whether polymorphisms of its encoding ABCB1 gene predict central side effects of cabergoline therapy in patients with PRL adenomas. i) In an experimental mouse model lacking the homologues of the human ABCB1 gene (Abcb1ab double knockout mouse model), we examined whether cabergoline is a substrate of the P-gp using eight mutant and eight wild-type mice. ii) In a human case-control study including 79 patients with PRL adenomas treated with cabergoline at the Max Planck Institute of Psychiatry in Munich, we investigated the association of four selected ABCB1 gene single nucleotide polymorphisms (SNPs) (rs1045642, rs2032582, rs2032583 and rs2235015), with the occurrence of central side effects under cabergoline therapy.

RESULTS

i) In the experimental mouse model, we observed that brain concentrations of cabergoline were tenfold higher in the mutant mice compared with their wild-type littermates, implying that cabergoline is indeed a substrate of the transporter P-gp at the blood-brain barrier level. ii) In the human study, we observed significant negative associations under cabergoline for the C-carriers and heterozygous CT individuals of SNP rs1045642 with two central side effects (frequency of fatigue and sleep disorders) and for the G-carriers of SNP rs2032582 with the enhancement of dizziness. For the SNPs rs2235015 and rs2032583, no associations with central side effects under cabergoline were found.

DISCUSSION

This is the first study demonstrating that individual ABCB1 gene polymorphisms, reflecting a different expression and function of the P-gp, could predict the occurrence of central side effects under cabergoline. Our findings can be viewed as a step into personalised therapy in PRL adenoma patients.

Global network reorganization during dynamic adaptations of Bacillus subtilis metabolism

Adaptation of cells to environmental changes requires dynamic interactions between metabolic and regulatory networks, but studies typically address only one or a few layers of regulation. For nutritional shifts between two preferred carbon sources of Bacillus subtilis, we combined statistical and model-based data analyses of dynamic transcript, protein, and metabolite abundances and promoter activities. Adaptation to malate was rapid and primarily controlled posttranscriptionally compared with the slow, mainly transcriptionally controlled adaptation to glucose that entailed nearly half of the known transcription regulation network. Interactions across multiple levels of regulation were involved in adaptive changes that could also be achieved by controlling single genes. Our analysis suggests that global trade-offs and evolutionary constraints provide incentives to favor complex control programs.

Closely related Campylobacter jejuni strains from different sources reveal a generalist rather than a specialist lifestyle

Background

Campylobacter jejuni and Campylobacter coli are human intestinal pathogens of global importance. Zoonotic transmission from livestock animals or animal-derived food is the likely cause for most of these infections. However, little is known about their general and host-specific mechanisms of colonization, or virulence and pathogenicity factors. In certain hosts, Campylobacter species colonize persistently and do not cause disease, while they cause acute intestinal disease in humans.

Results

Here, we investigate putative host-specificity using phenotypic characterization and genome-wide analysis of genetically closely related C. jejuni strains from different sources. A collection of 473 fresh Campylobacter isolates from Germany was assembled between 2006 and 2010 and characterized using MLST. A subset of closely related C. jejuni strains of the highly prevalent sequence type ST-21 was selected from different hosts and isolation sources. PCR typing of strain-variable genes provided evidence that some genes differed between these strains. Furthermore, phenotypic variation of these strains was tested using the following criteria: metabolic variation, protein expression patterns, and eukaryotic cell interaction. The results demonstrated remarkable phenotypic diversity within the ST-21 group, which however did not correlate with isolation source. Whole genome sequencing was performed for five ST-21 strains from chicken, human, bovine, and food sources, in order to gain insight into ST-21 genome diversity. The comparisons showed extensive genomic diversity, primarily due to recombination and gain of phage-related genes. By contrast, no genomic features associated with isolation source or host were identified.

Conclusions

The genome information and phenotypic data obtained in vitro and in a chicken infection model provided little evidence of fixed adaptation to a specific host. Instead, the dominant C. jejuni ST-21 appeared to be characterized by phenotypic flexibility and high genetic microdiversity, revealing properties of a generalist. High genetic flexibility might allow generalist variants of C. jejuni to reversibly express diverse fitness factors in changing environments.

AGNP Consensus Guidelines for Therapeutic Drug Monitoring in Psychiatry: Update 2011

Therapeutic drug monitoring (TDM), i. e., the quantification of serum or plasma concentrations of medications for dose optimization, has proven a valuable tool for the patient-matched psychopharmacotherapy. Uncertain drug adherence, suboptimal tolerability, non-response at therapeutic doses, or pharmacokinetic drug-drug interactions are typical situations when measurement of medication concentrations is helpful. Patient populations that may predominantly benefit from TDM in psychiatry are children, pregnant women, elderly patients, individuals with intelligence disabilities, forensic patients, patients with known or suspected genetically determined pharmacokinetic abnormalities or individuals with pharmacokinetically relevant comorbidities. However, the potential benefits of TDM for optimization of pharmacotherapy can only be obtained if the method is adequately integrated into the clinical treatment process. To promote an appropriate use of TDM, the TDM expert group of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued guidelines for TDM in psychiatry in 2004. Since then, knowledge has advanced significantly, and new psychopharmacologic agents have been introduced that are also candidates for TDM. Therefore the TDM consensus guidelines were updated and extended to 128 neuropsychiatric drugs. 4 levels of recommendation for using TDM were defined ranging from "strongly recommended" to "potentially useful". Evidence-based "therapeutic reference ranges" and "dose related reference ranges" were elaborated after an extensive literature search and a structured internal review process. A "laboratory alert level" was introduced, i. e., a plasma level at or above which the laboratory should immediately inform the treating physician. Supportive information such as cytochrome P450 substrate- and inhibitor properties of medications, normal ranges of ratios of concentrations of drug metabolite to parent drug and recommendations for the interpretative services are given. Recommendations when to combine TDM with pharmacogenetic tests are also provided. Following the guidelines will help to improve the outcomes of psychopharmacotherapy of many patients especially in case of pharmacokinetic problems. Thereby, one should never forget that TDM is an interdisciplinary task that sometimes requires the respectful discussion of apparently discrepant data so that, ultimately, the patient can profit from such a joint effort.

AGNP consensus guidelines for therapeutic drug monitoring in psychiatry: update 2011

Therapeutic drug monitoring (TDM), i. e., the quantification of serum or plasma concentrations of medications for dose optimization, has proven a valuable tool for the patient-matched psychopharmacotherapy. Uncertain drug adherence, suboptimal tolerability, non-response at therapeutic doses, or pharmacokinetic drug-drug interactions are typical situations when measurement of medication concentrations is helpful. Patient populations that may predominantly benefit from TDM in psychiatry are children, pregnant women, elderly patients, individuals with intelligence disabilities, forensic patients, patients with known or suspected genetically determined pharmacokinetic abnormalities or individuals with pharmacokinetically relevant comorbidities. However, the potential benefits of TDM for optimization of pharmacotherapy can only be obtained if the method is adequately integrated into the clinical treatment process. To promote an appropriate use of TDM, the TDM expert group of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued guidelines for TDM in psychiatry in 2004. Since then, knowledge has advanced significantly, and new psychopharmacologic agents have been introduced that are also candidates for TDM. Therefore the TDM consensus guidelines were updated and extended to 128 neuropsychiatric drugs. 4 levels of recommendation for using TDM were defined ranging from “strongly recommended” to “potentially useful”. Evidence-based “therapeutic reference ranges” and “dose related reference ranges” were elaborated after an extensive literature search and a structured internal review process. A “laboratory alert level” was introduced, i. e., a plasma level at or above which the laboratory should immediately inform the treating physician. Supportive information such as cytochrome P450 substrate and inhibitor properties of medications, normal ranges of ratios of concentrations of drug metabolite to parent drug and recommendations for the interpretative services are given. Recommendations when to combine TDM with pharmacogenetic tests are also provided. Following the guidelines will help to improve the outcomes of psychopharmacotherapy of many patients especially in case of pharmacokinetic problems. Thereby, one should never forget that TDM is an interdisciplinary task that sometimes requires the respectful discussion of apparently discrepant data so that, ultimately, the patient can profit from such a joint eff ort.

More CLEC16A gene variants associated with multiple sclerosis

OBJECTIVES

Recently, associations of several single-nucleotide polymorphisms (SNPs) within the CLEC16A gene with multiple sclerosis (MS), type-I diabetes, and primary adrenal insufficiency were reported.

METHODS

We performed linkage disequilibrium (LD) fine mapping with 31 SNPs from this gene, searching for the region of highest association with MS in a German sample consisting of 603 patients and 825 controls.

RESULTS

Four SNPs located in intron 19 of the CLEC16A gene were found associated. We could replicate the finding for SNP rs725613 and were able to show for the first time the association of rs2041670, rs2080272 and rs998592 with MS.

CONCLUSION

All described base polymorphisms are mapping to one LD block of approximately 50 kb within intron 19 of the CLEC16A gene, suggesting a pivotal role of this region for susceptibility of MS and possibly also for other autoimmune diseases.

Single-nucleotide polymorphisms in HLA- and non-HLA genes associated with the development of antibodies to interferon-β therapy in multiple sclerosis patients

Interferons-β (IFN-β) are the most widely used immunomodulatory drugs for treatment of multiple sclerosis (MS). The development of neutralizing antibodies (NABs) against IFN-β is one of the main reasons for treatment failure. While formulation of the drug has a proven impact on the development of NABs, the genetic predisposition to develop antibodies is poorly understood. We performed genome-wide single-nucleotide polymorphism (SNP) genotyping in 362 MS patients of whom 178 had developed and 184 had not developed antibodies on IFN-β therapy. Four candidate SNPs were validated in an independent cohort of 350 antibody-positive and 468 antibody-negative MS patients. One SNP within the human leucocyte antigen (HLA) region (rs9272105, P-value: 3.56 × 10⁻¹⁰) and one SNP in an intergenic region on chromosome 8q24.3 (rs4961252, P-value: 2.92 × 10⁻⁸ showed a genome-wide significant association with the anti-IFN-β antibody titers. We found no interaction between the genome-wide significant SNPs (rs9272105 and rs4961252) in our study and the previously described HLA-DR*0401 or *0408 alleles, indicating an additive effect of SNPs and HLA alleles. Testing for these SNPs and the HLA-DR*0401 or *0408 alleles allows to identify patients at risk to develop antibodies to IFN-β and may provide helpful information for individual treatment decisions.

Effects of lithium on the HPA axis in patients with unipolar major depression

Background

(I)

Design and methods

Three 4-week studies with each 30 acutely depressed patients (unipolar, SCID I confirmed) were conducted. In study 1, patients refractory to a treatment trial with an antidepressant of at least four weeks were treated with lithium augmentation. In study 2 and 3, drug free patients were treated with lithium monotherapy or citalopram monotherapy respectively. Weekly HAM-D ratings were performed. In each study, the DEX/CRH test was conducted right before and four weeks after initiation of the pharmacotherapy.

Results

All three pharmacological strategies showed good antidepressive efficacy. Both lithium monotherapy and lithium augmentation led to a (for most parameters significant) increase in the HPA axis activity. In contrast, citalopram monotherapy resulted in a decrease of the hormone response to the DEX/CRH test.

A high-resolution anatomical atlas of the transcriptome in the mouse embryo

The manuscript describes the “digital transcriptome atlas” of the developing mouse embryo, a powerful resource to determine co-expression of genes, to identify cell populations and lineages and to identify functional associations between genes relevant to development and disease.

Ascertaining when and where genes are expressed is of crucial importance to understanding or predicting the physiological role of genes and proteins and how they interact to form the complex networks that underlie organ development and function. It is, therefore, crucial to determine on a genome-wide level, the spatio-temporal gene expression profiles at cellular resolution. This information is provided by colorimetric RNA in situ hybridization that can elucidate expression of genes in their native context and does so at cellular resolution. We generated what is to our knowledge the first genome-wide transcriptome atlas by RNA in situ hybridization of an entire mammalian organism, the developing mouse at embryonic day 14.5. This digital transcriptome atlas, the Eurexpress atlas (http://www.eurexpress.org), consists of a searchable database of annotated images that can be interactively viewed. We generated anatomy-based expression profiles for over 18,000 coding genes and over 400 microRNAs. We identified 1,002 tissue-specific genes that are a source of novel tissue-specific markers for 37 different anatomical structures. The quality and the resolution of the data revealed novel molecular domains for several developing structures, such as the telencephalon, a novel organization for the hypothalamus, and insight on the Wnt network involved in renal epithelial differentiation during kidney development. The digital transcriptome atlas is a powerful resource to determine co-expression of genes, to identify cell populations and lineages, and to identify functional associations between genes relevant to development and disease.

In situ hybridization (ISH) can be used to visualize gene expression in cells and tissues in their native context. High-throughput ISH using nonradioactive RNA probes allowed the Eurexpress consortium to generate a comprehensive, interactive, and freely accessible digital gene expression atlas, the Eurexpress transcriptome atlas (http://www.eurexpress.org), of the E14.5 mouse embryo. Expression data for over 15,000 genes were annotated for hundreds of anatomical structures, thus allowing us to systematically identify tissue-specific and tissue-overlapping gene networks. We illustrate the value of the Eurexpress atlas by finding novel regional subdivisions in the developing brain. We also use the transcriptome atlas to allocate specific components of the complex Wnt signaling pathway to kidney development, and we identify regionally expressed genes in liver that may be markers of hematopoietic stem cell differentiation.

Intrahippocampal corticosterone response in mice selectively bred for extremes in stress reactivity: a microdialysis study

The hypothalamic-pituitary-adrenocortical (HPA) axis is one of the major stress hormone systems, and glucocorticoids (GCs) play a pivotal role in homeostatic processes throughout the body and brain. A dysregulation of the HPA axis, leading to an aberrant secretion of GCs, is associated with affective disorders such as major depression. In the present study, three mouse lines selectively bred for high (HR), intermediate (IR) or low (LR) stress reactivity were used to elucidate the temporal dynamics of intrahippocampal corticosterone (CORT) in response to a standardised stressor. In particular, we addressed the question of whether the distinct differences in HPA axis reactivity between the three mouse lines, as determined by plasma CORT measurements, are present in the central nervous system as well, and if the respective endophenotype is brought about by alterations in blood-brain barrier (BBB) functionality. We applied in vivo microdialysis in the hippocampus, demonstrating that the concentrations of CORT released from the adrenals in response to restraint stress are not only distinctly different in the plasma, but can also be found in the central nervous system, although the differences between the three mouse lines were attenuated, particularly between IR and LR animals. Additionally, a time lag of approximately 60 min was observed in all three lines regarding intrahippocampal peak concentrations of CORT after the onset of the stressor. Furthermore, we showed that the penetration and clearance of CORT in the hippocampal tissue was not affected by differences in BBB functionality because the multidrug resistance 1 P-glycoprotein (Mdr1 Pgp) was equally expressed in HR, IR and LR mice. Furthermore, we could exclude surgical damage of the BBB because peripherally-injected dexamethasone, which is a high affinity substrate for the Mdr1 Pgp and therefore restricted from entering the brain, could only be detected in the plasma and was virtually absent in the brain.

A global overview of the genetic and functional diversity in the Helicobacter pylori cag pathogenicity island

The Helicobacter pylori cag pathogenicity island (cagPAI) encodes a type IV secretion system. Humans infected with cagPAI–carrying H. pylori are at increased risk for sequelae such as gastric cancer. Housekeeping genes in H. pylori show considerable genetic diversity; but the diversity of virulence factors such as the cagPAI, which transports the bacterial oncogene CagA into host cells, has not been systematically investigated. Here we compared the complete cagPAI sequences for 38 representative isolates from all known H. pylori biogeographic populations. Their gene content and gene order were highly conserved. The phylogeny of most cagPAI genes was similar to that of housekeeping genes, indicating that the cagPAI was probably acquired only once by H. pylori, and its genetic diversity reflects the isolation by distance that has shaped this bacterial species since modern humans migrated out of Africa. Most isolates induced IL-8 release in gastric epithelial cells, indicating that the function of the Cag secretion system has been conserved despite some genetic rearrangements. More than one third of cagPAI genes, in particular those encoding cell-surface exposed proteins, showed signatures of diversifying (Darwinian) selection at more than 5% of codons. Several unknown gene products predicted to be under Darwinian selection are also likely to be secreted proteins (e.g. HP0522, HP0535). One of these, HP0535, is predicted to code for either a new secreted candidate effector protein or a protein which interacts with CagA because it contains two genetic lineages, similar to cagA. Our study provides a resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown.

Most humans are infected with Helicobacter pylori. The H. pylori cag pathogenicity island (cagPAI) encodes a secretion apparatus that can translocate the CagA protein into host cells. Humans infected with cagPAI–carrying H. pylori are at increased risk of severe disease, including gastric cancer. We analyzed the nucleotide sequences and functional diversity of the cagPAI in a globally representative collection of isolates. Complete cagPAI sequences were obtained for 29 strains from all known H. pylori biogeographic populations. The gene content and arrangement of the cagPAI and its function were highly conserved. Diversity in most cag genes consisted in large part of synonymous polymorphisms. However some genes—in particular those that encode proteins predicted to be secreted or located on the outside of the bacterial cell—had particularly high frequencies of non-synonymous polymorphisms, suggesting that they were under diversifying selection. Our study provides evidence that the cagPAI was only acquired once and provides an important resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown.