Lithium Therapy in Old Age: Recommendations from a Delphi Survey.

INTRODUCTION: While lithium (Li) has been well established for the treatment of bipolar disorder, geriatric patients require special attention when it comes to issues of drug safety. Declining renal function, amongst other medical conditions, and polypharmacy may pose increased risks. Only a few previous studies have addressed the management of Li in geriatric patients. METHODS: Twenty-four German medical experts on geriatric medicine and Li treatment participated in a Delphi survey, consisting of two rounds of questionnaires and a final formulation of treatment recommendations. Three major issues of Li therapy were outlined: initiation of treatment, monitoring of ongoing therapy, and withdrawal due to medical reasons. Final recommendations were consented to at a threshold of at least 80% expert agreement. RESULTS: Final consensus was achieved on 21 clinical recommendations. The approved recommendations covered aspects of necessary laboratory checks, concomitant medication, and target Li serum concentration in geriatric patients. Concerning the termination of Li therapy, an agreement was reached on the appropriate time span for tapering and on potential alternatives to Li. No consensus was achieved on whether concomitant dementia or frailty should be considered contraindications for Li treatment and the appropriate threshold of the estimated glomerular function rate for withdrawing Li. CONCLUSION: According to the view of German experts, Li may be used in geriatric patients, but it should be monitored carefully. However, the lack of consent in several specific treatment situations underlines the need for research on specific issues of Li therapy.

[Identification of polypharmacy-associated risks among nursing home residents]. / Risikoidentifikation bei Polypharmazie in einer Pflegeheimpopulation.

INTRODUCTION: Multimorbidity in old age is one reason for intensified pharmacotherapy. At the same time, an increase in medications could augment multimorbidity, especially when drug interactions leading to undesired drug effects occur. METHODS: In this cross-sectional study 918 mentally ill seniors living in nursing homes (mean age 79.3 (±11.6) years; 31.8% male) were included. Two different approaches to assess risks due to pharmacotherapy were applied: first mediQ, an online-based clinical decision support software (CDSS) and the PRISCUS list, which indicates potentially inappropriate medication. PRISCUS is the German equivalent to the American Geriatrics Society Beers criteria. RESULTS: Of the patients in the study 76.3% were at clinical risk, 2.2% at potentially high risk for drug interactions regarding the entire medication as tested by mediQ, and about 25% of the studied population received potentially inappropriate medication according to the PRISCUS list. CONCLUSION: This difference clearly underlines the cumbersome complexity of identifying patients at risk by using these exemplary devices. The focus of avoiding undesired drug side effects should be taking medication only after thorough verification of clinical indications and under close monitoring. The CDSS or negative lists may support this process.

Exposure to 1-Butanol Exemplifies the Response of the Thermoacidophilic Archaeon Sulfolobus acidocaldarius to Solvent Stress.

Sulfolobus acidocaldarius is a thermoacidophilic crenarchaeon with optimal growth at 80°C and pH 2 to 3. Due to its unique physiological properties, allowing life at environmental extremes, and the recent availability of genetic tools, this extremophile has received increasing interest for biotechnological applications. In order to elucidate the potential of tolerating process-related stress conditions, we investigated the response of S. acidocaldarius toward the industrially relevant organic solvent 1-butanol. In response to butanol exposure, biofilm formation of S. acidocaldarius was enhanced and occurred at up to 1.5% (vol/vol) 1-butanol, while planktonic growth was observed at up to 1% (vol/vol) 1-butanol. Confocal laser-scanning microscopy revealed that biofilm architecture changed with the formation of denser and higher tower-like structures. Concomitantly, changes in the extracellular polymeric substances with enhanced carbohydrate and protein content were determined in 1-butanol-exposed biofilms. Using scanning electron microscopy, three different cell morphotypes were observed in response to 1-butanol. Transcriptome and proteome analyses were performed comparing the response of planktonic and biofilm cells in the absence and presence of 1-butanol. In response to 1% (vol/vol) 1-butanol, transcript levels of genes encoding motility and cell envelope structures, as well as membrane proteins, were reduced. Cell division and/or vesicle formation were upregulated. Furthermore, changes in immune and defense systems, as well as metabolism and general stress responses, were observed. Our findings show that the extreme lifestyle of S.acidocaldarius coincided with a high tolerance to organic solvents. This study provides what may be the first insights into biofilm formation and membrane/cell stress caused by organic solvents in S. acidocaldariusIMPORTANCEArchaea are unique in terms of metabolic and cellular processes, as well as the adaptation to extreme environments. In the past few years, the development of genetic systems and biochemical, genetic, and polyomics studies has provided deep insights into the physiology of some archaeal model organisms. In this study, we used S. acidocaldarius, which is adapted to the two extremes of low pH and high temperature, to study its tolerance and robustness as well as its global cellular response toward organic solvents, as exemplified by 1-butanol. We were able to identify biofilm formation as a primary cellular response to 1-butanol. Furthermore, the triggered cell/membrane stress led to significant changes in culture heterogeneity accompanied by changes in central cellular processes, such as cell division and cellular defense systems, thus suggesting a global response for the protection at the population level.

Structural insights into the NAD+-dependent formate dehydrogenase mechanism revealed from the NADH complex and the formate NAD+ ternary complex of the Chaetomium thermophilum enzyme.

The removal of carbon dioxide from the waste streams of industrial processes is a major challenge for creation of a sustainable circular economy. This makes the synthesis of formate from CO2 by NAD+ dependent formate dehydrogenases (FDHs) an attractive process for this purpose. The efficiency of this reaction is however low and to achieve a viable industrial process an optimised engineered enzyme needs to be developed. In order to understand the detailed enzymatic mechanism of catalysis structures of different cofactor and substrate complexes of the FDH from the thermophilic filamentous fungus, Chaetomium thermophilum have been determined to 1.2-1.3 Å resolution. The substrate formate is shown to be held by four hydrogen bonds in the FDH catalytic site within the ternary complex with substrate and NAD+and a secondary formate binding site is observed in crystals soaked with substrate. Water molecules are excluded from the FDH catalytic site when the substrate is bound. The angle between the plane of the NAD+ cofactor pyridine ring and the plane of the formate molecule is around 27°. Additionally, structures of a FDH mutant enzyme, N120C, in complex with the reduced form of the cofactor have also been determined both in the presence and absence of formate bound at the secondary site. These structures provide further understanding of the catalytic mechanism of this fungal enzyme.

Trehalose as glucose surrogate in proliferation and cellular mobility of adult neural progenitor cells derived from mouse hippocampus.

The disaccharide trehalose (TRE) represents a natural energy supply for distinct non-mammalian species. Evidence has shown that TRE impacts on various properties including the stabilization of protein structure and cell membranes, which are important neuroprotective features against neurodegeneration. In this study, we tested the specific effect of TRE on cell proliferation and mobilization using an established experimental paradigm of adult neural progenitor cells (NPCs) derived from murine hippocampus. NPC proliferation, both measured by growth curve analysis over 25 days and by bromodeoxyuridine (BrdU) incorporation, was not altered by adding TRE instead of GLC to the culture media. Using Boyden chamber experiments, the mobility in regular glucose-containing media did not differ from glucose-free TRE-supplemented media. Our observation suggests that TRE has the capacity to replace glucose (GLC) as energy source in neural cells in our experimental paradigm.

[Bipolar affective disorders in senescence]. / Bipolare affektive Störungen im höheren Lebensalter.

Diagnostic and therapeutic measures in patients with bipolar disorders are significantly different depending on the age of those affected. Given the demographic changes and the fact that approximately one quarter of patients with bipolar disease are in old age, it is important for geriatricians to be aware of the specific aspects of bipolar disease. This review article presents the diagnostics of bipolar disorders in old people. Interactions with somatic comorbidities, which may lead to the occurrence of secondary mania, just to mention one of the characteristics of old age, are elaborated. Furthermore, age-specific differences also necessitate altered or adjusted therapy regimens, which deviate from those of younger patients.

Effect of replacing maize grain and soybean meal with a xylose-treated wheat grain on feed intake and performance of dairy cows.

This study evaluated wheat grain which was treated with xylose in aqueous Ca-Mg lignosulphonate solution at elevated temperatures (WeiPass®) in order to reduce ruminal degradation of starch and crude protein. The two tested isoenergetic and isonitrogenous diets contained on dry matter (DM) basis either 16% maize grain and 6.4% soybean meal (Diet CON) or 17.8% xylose-treated wheat and 4.6% soybean meal (Diet Wheat). Thirty-six German Holstein dairy cows were assigned to one of the two groups according to parity, body weight after calving, and milk yield during the previous lactation. Data collection started at 21 d before the expected calving date until 120 d in milk. The average of DM intake, energy-corrected milk (ECM) yield, and milk fat and protein yields (all given as kg/d) were 18.9, 28.7, 1.25, and 1.02 for Diet CON and 19.3, 32.5, 1.36, and 1.11 for Diet Wheat, respectively. Only ECM and milk protein yields were greater (p < 0.05) for cows receiving Diet Wheat. In conclusion, the xylose-treated wheat grain can replace maize grain and part of soybean meal in diets for lactating dairy cows and may be an alternative feedstuff depending on overall ration composition and availability and costs of grain sources.

Methylene Blue (Tetramethylthionine Chloride) Influences the Mobility of Adult Neural Stem Cells: A Potentially Novel Therapeutic Mechanism of a Therapeutic Approach in the Treatment of Alzheimer's Disease.

An interest in neurogenesis in the adult human brain as a relevant and targetable process has emerged as a potential treatment option for Alzheimer's disease and other neurodegenerative conditions. The aim of this study was to investigate the effects of tetramethylthionine chloride (methylene blue, MB) on properties of adult murine neural stem cells. Based on recent clinical studies, MB has increasingly been discussed as a potential treatment for Alzheimer's disease. While no differences in the proliferative capacity were identified, a general potential of MB in modulating the migratory capacity of adult neural stem cells was indicated in a cell mobility assay. To our knowledge, this is the first time that MB could be associated with neural mobility. The results of this study add insight to the spectrum of features of MB within the central nervous system and may be helpful for understanding the molecular mechanisms underlying a potential therapeutic effect of MB.

Longitudinal reproducibility of default-mode network connectivity in healthy elderly participants: A multicentric resting-state fMRI study.

To date, limited data are available regarding the inter-site consistency of test-retest reproducibility of functional connectivity measurements, in particular with regard to integrity of the Default Mode Network (DMN) in elderly participants. We implemented a harmonized resting-state fMRI protocol on 13 clinical scanners at 3.0T using vendor-provided sequences. Each site scanned a group of 5 healthy elderly participants twice, at least a week apart. We evaluated inter-site differences and test-retest reproducibility of both temporal signal-to-noise ratio (tSNR) and functional connectivity measurements derived from: i) seed-based analysis (SBA) with seed in the posterior cingulate cortex (PCC), ii) group independent component analysis (ICA) separately for each site (site ICA), and iii) consortium ICA, with group ICA across the whole consortium. Despite protocol harmonization, significant and quantitatively important inter-site differences remained in the tSNR of resting-state fMRI data; these were plausibly driven by hardware and pulse sequence differences across scanners which could not be harmonized. Nevertheless, the tSNR test-retest reproducibility in the consortium was high (ICC=0.81). The DMN was consistently extracted across all sites and analysis methods. While significant inter-site differences in connectivity scores were found, there were no differences in the associated test-retest error. Overall, ICA measurements were more reliable than PCC-SBA, with site ICA showing higher reproducibility than consortium ICA. Across the DMN nodes, the PCC yielded the most reliable measurements (≈4% test-retest error, ICC=0.85), the medial frontal cortex the least reliable (≈12%, ICC=0.82) and the lateral parietal cortices were in between (site ICA). Altogether these findings support usage of harmonized multisite studies of resting-state functional connectivity to characterize longitudinal effects in studies that assess disease progression and treatment response.

Does trans-10, cis-12 conjugated linoleic acid affect the intermediary glucose and energy expenditure of dairy cows due to repartitioning of milk component synthesis?

The overall goal of this study was to evaluate if intermediary energy metabolism of cows fed with trans-10, cis-12 conjugated linoleic acid (CLA) was modified such that milk-energy compounds were produced with less intermediary energy expenditure as compared to control cows. Published data on supplemented CLA were assembled. The extent was calculated to which the trans-10, cis-12 CLA isomer has an impact on glucose and energy conversion in the mammary gland by modifying glucose equivalent supply and energy required for fatty acid (FA) and fat synthesis, and if this will eventually lead to an improved glucose and energy status of CLA-supplemented high-yielding dairy cows. A possible relationship between CLA supplementation level and milk energy yield response was also studied. Calculations were conducted separately for orally and abomasally administered CLA and based on energy required for supply of glucose equivalents, i.e. lactose, glycerol and NADPH2. Further, modifications of milk FA profile due to CLA supplementation were considered when energy expenditures for FA and fat synthesis were quantified. Differences in yields between control and CLA groups were transformed into glucose energy equivalents. Only abomasal infusion (r(2) = 0.31) but not oral CLA administration (r(2) = 0.11) supplementation to dairy cow diets resulted in less glucose equivalent energy. Modifications of milk FA profiles also saved energy but the relationship with CLA supplementation was weaker for abomasal infusion (r(2) = 0.06) than oral administration (r(2) = 0.38). On average, 10 g/d of abomasally infused trans-10, cis-12 CLA saved 1.1 to 2.3 MJ net energy expressed as glucose equivalents, whereas both positive and negative values were observed when the trans-10, cis-12 CLA was fed to the cows. This study revealed a weak to moderate dose-dependent relationship between the amount of trans-10, cis-12 CLA administered and the amount of energy in glucose equivalents and energy for the synthesis of milk fat conserved from milk ingredient synthesis. Because abomasal infusion of the trans-10, cis-12 CLA more consistently conserved energy in glucose equivalents compared with oral CLA intake, rumen protection of the fed CLA products appears incomplete. Milk fat synthesis showed an energy saving with a weak dose-dependent relationship when CLA was supplemented orally or by abomasal infusion.

Estimation of intestinal protein digestibility of protein supplements for ruminants using a three-step enzymatic in vitro procedure.

This study included 33 samples with main focus on unprotected or rumen-protected rapeseed and soybean feedstuffs, which were analysed using an enzymatic in vitro procedure (EIVP) in order to determine intestinal crude protein (CP) digestibility (IPD) of ruminally undegraded CP. The EIVP involved the sequential digestion of samples with a protease from Streptomyces griseus, pepsin-HCl and pancreatin. Briefly, the EIVP started with determination of true protein. Feeds were incubated for 18 h in a buffer solution at a constant ratio (41 U/g) of S. griseus protease activity to feed true protein. The dried residues were incubated in pepsin-HCl solution for 1 h, and residues from this step were incubated in pancreatin solution for 24 h. Results appeared to have lower IPD dimensions than literature data of previous studies. In addition, a negative correlation became apparent between acid detergent fibre and IPD, as well as a positive correlation between CP, true protein and IPD. The EIVP in its current, strictly standardised form can be applied to develop a database that can be used for protein evaluation systems for establishing tabular values of IPD. Nevertheless, future studies may be hindered since sufficient reference values, i.e. in vivo data, are completely missing.

Multisite longitudinal reliability of tract-based spatial statistics in diffusion tensor imaging of healthy elderly subjects.

Large-scale longitudinal neuroimaging studies with diffusion imaging techniques are necessary to test and validate models of white matter neurophysiological processes that change in time, both in healthy and diseased brains. The predictive power of such longitudinal models will always be limited by the reproducibility of repeated measures acquired during different sessions. At present, there is limited quantitative knowledge about the across-session reproducibility of standard diffusion metrics in 3T multi-centric studies on subjects in stable conditions, in particular when using tract based spatial statistics and with elderly people. In this study we implemented a multi-site brain diffusion protocol in 10 clinical 3T MRI sites distributed across 4 countries in Europe (Italy, Germany, France and Greece) using vendor provided sequences from Siemens (Allegra, Trio Tim, Verio, Skyra, Biograph mMR), Philips (Achieva) and GE (HDxt) scanners. We acquired DTI data (2 × 2 × 2 mm(3), b = 700 s/mm(2), 5 b0 and 30 diffusion weighted volumes) of a group of healthy stable elderly subjects (5 subjects per site) in two separate sessions at least a week apart. For each subject and session four scalar diffusion metrics were considered: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial (AD) diffusivity. The diffusion metrics from multiple subjects and sessions at each site were aligned to their common white matter skeleton using tract-based spatial statistics. The reproducibility at each MRI site was examined by looking at group averages of absolute changes relative to the mean (%) on various parameters: i) reproducibility of the signal-to-noise ratio (SNR) of the b0 images in centrum semiovale, ii) full brain test-retest differences of the diffusion metric maps on the white matter skeleton, iii) reproducibility of the diffusion metrics on atlas-based white matter ROIs on the white matter skeleton. Despite the differences of MRI scanner configurations across sites (vendors, models, RF coils and acquisition sequences) we found good and consistent test-retest reproducibility. White matter b0 SNR reproducibility was on average 7 ± 1% with no significant MRI site effects. Whole brain analysis resulted in no significant test-retest differences at any of the sites with any of the DTI metrics. The atlas-based ROI analysis showed that the mean reproducibility errors largely remained in the 2-4% range for FA and AD and 2-6% for MD and RD, averaged across ROIs. Our results show reproducibility values comparable to those reported in studies using a smaller number of MRI scanners, slightly different DTI protocols and mostly younger populations. We therefore show that the acquisition and analysis protocols used are appropriate for multi-site experimental scenarios.

5-HT3 receptor influences the washing phenotype and visual organization in obsessive-compulsive disorder supporting 5-HT3 receptor antagonists as novel treatment option.

A role of the HTR3A-E genes in obsessive-compulsive disorder (OCD) can be expected based on promising effects of 5-HT3 receptor antagonists as adjunctive treatment of OCD. We therefore genotyped six common coding or promoter variants within the HTR3A-E genes in a case-control-sample consisting of N=236 OCD patients and N=310 control subjects and in N=58 parent-child-trios. Given the heterogeneous OCD phenotype, we also investigated OCD symptom dimensions and cognitive endophenotypes in subsamples. OCD patients scoring high for the washing subtype were significantly more likely to carry the c.256G-allele of the HTR3E variant rs7627615 (p=0.0001) as compared to OCD patients low for this symptom dimension. Visual organization was impaired in OCD patients and unaffected relatives as compared to healthy control subjects and carriers of the HTR3E c.256G/c.256G-genotype performed significantly worse (p=0.007). The case-control analyses revealed a nominal significant association of the HTR3D variant rs1000592 (p.H52R) with OCD (p=0.029) which was also evident after combination of the case-control and the trio-results (p=0.024). In male subjects, the variant rs6766410 (p.N163K) located in the HTR3C was significantly associated with OCD (p=0.007). The association findings of the HTR3C and the HTR3E remained significant after correction for the number of variants investigated. These findings indicate a role of common variants of the HTR3A-E genes in OCD and OCD-related phenotypes and further support the use of 5-HT3 receptor antagonists as novel treatment options. The HTR3E gene is a novel candidate gene impacting on the individual expression of OC symptoms and OCD-related cognitive dysfunction.

Glutamatergic dysbalance and oxidative stress in in vivo and in vitro models of psychosis based on chronic NMDA receptor antagonism.

BACKGROUND: The psychotomimetic effects of N-methyl-D-aspartate (NMDA) receptor antagonists in healthy humans and their tendency to aggravate psychotic symptoms in schizophrenic patients have promoted the notion of altered glutamatergic neurotransmission in the pathogenesis of schizophrenia. METHODS: The NMDA-receptor antagonist MK-801 was chronically administered to rats (0.02 mg/kg intraperitoneally for 14 days). In one subgroup the antipsychotic haloperidol (1 mg/kg) was employed as a rescue therapy. Glutamate distribution and 3-NT (3-nitrotyrosine) as a marker of oxidative stress were assessed by immunohistochemistry in tissue sections. In parallel, the effects of MK-801 and haloperidol were investigated in primary embryonal hippocampal cell cultures from rats. RESULTS: Chronic NMDA-R antagonism led to a marked increase of intracellular glutamate in the hippocampus (126.1 +/- 10.4% S.E.M of control; p=0.037), while 3-NT staining intensity remained unaltered. No differences were observed in extrahippocampal brain regions. Essentially these findings could be reproduced in vitro. CONCLUSION: The combined in vivo and in vitro strategy allowed us to assess the implications of disturbed glutamate metabolism for the occurrence of oxidative stress and to investigate the effects of antipsychotics. Our data suggest that oxidative stress plays a minor role in this model than previously suggested. The same applies to apoptosis. Moreover, the effect of haloperidol seems to be mediated through yet unidentified mechanisms, unrelated to D2-antagonism. These convergent lines of evidence indicate that further research should be focused on the glutamatergic system and that our animal model may provide a tool to explore the biology of schizophrenia.

Brain morphometry reproducibility in multi-center 3T MRI studies: a comparison of cross-sectional and longitudinal segmentations.

Large-scale longitudinal multi-site MRI brain morphometry studies are becoming increasingly crucial to characterize both normal and clinical population groups using fully automated segmentation tools. The test-retest reproducibility of morphometry data acquired across multiple scanning sessions, and for different MR vendors, is an important reliability indicator since it defines the sensitivity of a protocol to detect longitudinal effects in a consortium. There is very limited knowledge about how across-session reliability of morphometry estimates might be affected by different 3T MRI systems. Moreover, there is a need for optimal acquisition and analysis protocols in order to reduce sample sizes. A recent study has shown that the longitudinal FreeSurfer segmentation offers improved within session test-retest reproducibility relative to the cross-sectional segmentation at one 3T site using a nonstandard multi-echo MPRAGE sequence. In this study we implement a multi-site 3T MRI morphometry protocol based on vendor provided T1 structural sequences from different vendors (3D MPRAGE on Siemens and Philips, 3D IR-SPGR on GE) implemented in 8 sites located in 4 European countries. The protocols used mild acceleration factors (1.5-2) when possible. We acquired across-session test-retest structural data of a group of healthy elderly subjects (5 subjects per site) and compared the across-session reproducibility of two full-brain automated segmentation methods based on either longitudinal or cross-sectional FreeSurfer processing. The segmentations include cortical thickness, intracranial, ventricle and subcortical volumes. Reproducibility is evaluated as absolute changes relative to the mean (%), Dice coefficient for volume overlap and intraclass correlation coefficients across two sessions. We found that this acquisition and analysis protocol gives comparable reproducibility results to previous studies that used longer acquisitions without acceleration. We also show that the longitudinal processing is systematically more reliable across sites regardless of MRI system differences. The reproducibility errors of the longitudinal segmentations are on average approximately half of those obtained with the cross sectional analysis for all volume segmentations and for entorhinal cortical thickness. No significant differences in reliability are found between the segmentation methods for the other cortical thickness estimates. The average of two MPRAGE volumes acquired within each test-retest session did not systematically improve the across-session reproducibility of morphometry estimates. Our results extend those from previous studies that showed improved reliability of the longitudinal analysis at single sites and/or with non-standard acquisition methods. The multi-site acquisition and analysis protocol presented here is promising for clinical applications since it allows for smaller sample sizes per MRI site or shorter trials in studies evaluating the role of potential biomarkers to predict disease progression or treatment effects.

Atypical parkinsonism due to a D202N Gerstmann-Sträussler-Scheinker prion protein mutation: first in vivo diagnosed case.

BACKGROUND: Parkinsonism with dopa-sensitivity and a correlating DaTSCAN turned out to be due to a D202N mutation which is associated with the Gerstmann-Sträussler-Scheinker (GSS) disease. METHODS/RESULTS: We report a 51-year old female who presented with left-dominant parkinsonism and a positive DaTSCAN. She was diagnosed with idiopathic Parkinson's syndrome. Dopaminergic medication reduced her symptoms. In addition, punding-like behavior, deficits in organizing daily life and abnormal sleep behavior were reported. Neuropsychological testing, EEG, polysomnography as well as PET imaging with fluorodexyglucose (FDG), [F-18]-desmethoxyfallypride (DMFP), and [C-11]-6-OH-BTA-1 (PIB) were not diagnostic. Cerebral spinal fluid analysis revealed no 14-3-3 protein, but elevated neuron-specific enolase (NSE) and S100-beta and a very low phospho-tau/total-tau ratio. Analysis of the prion gene disclosed the rare D202N mutation. CONCLUSIONS: The D202N prion mutation has been associated with GSS pathology and up to now was only reported post mortem. Our patient is the very first case diagnosed in vivo.

Cholinergic impact on neuroplasticity drives muscarinic M1 receptor mediated differentiation into neurons.

OBJECTIVES: Increasing evidence indicates that canonical neurotransmitters act as regulatory signals during neuroplasticity. Here, we report that muscarinic cholinergic neurotransmission stimulates differentiation of adult neural stem cells in vitro. METHODS: Adult neural stem cells (ANSC) dissociated from the adult mouse hippocampus were expanded in culture with basic fibroblast growth factor (BFGF) and epidermal growth factor (EGF). RESULTS: Carbachol (CCh), an analog of acetylcholine (ACh) significantly enhanced de novo differentiation into neurons on bFGF- and EGF-deprived stem cells as shown by the percentage of TUJ1 positive cells. By contrast, pirenzepine (PIR), a muscarinic M1 receptor antagonist, reduced the generation of neurons. CONCLUSION: Activation of cholinergic signaling drives the de novo differentiation of uncommitted stem cells into neurons. These effects appear to be predominantly mediated via the muscarinic M1 receptor subtype.

Investigation of tryptophan hydroxylase 2 (TPH2) in schizophrenia and in the response to antipsychotics.

Serotonergic transmission is considered relevant in the pathophysiology and the treatment of schizophrenia. Tryptophan hydroxylase (TPH) is the rate limiting enzyme in the biosynthesis of serotonin. While the TPH1 gene has been found to be associated with schizophrenia, studies focusing on TPH2 variants did not yield conclusive results for schizophrenia or the response to antipsychotic medication. We analyzed eleven TPH2 SNPs in two case-control samples consisting of 4453 individuals in total. Six SNPs were selected because of their potential functional relevance (rs4570625, rs11178997, rs11178998, rs7954758, rs7305115, and, rs4290270) and were supported by another 5 tagging SNPs selected based on HapMap LD information. In the discovery sample (1476 individuals), we observed a significant association with schizophrenia for rs10784941 (p = 0.009, OR minor G-allele 0.82 [0.71-0.95]) and rs4565946 (p = 0.011, OR minor T-allele 0.83 [0.71-0.96]). Association was also observed with a common rs4570625-rs4565946 haplotype (OR G-C haplotype 1.20 [1.02-1.40]; p = 0.0046). Single-marker associations could not be replicated in the replication sample consisting of 2977 individuals, but there was a strong trend regarding the rs4570625-rs4565946 G-C haplotype (OR 1.10 [0.98-1.24]; p(one-sided test) = 0.054). In smaller sub-samples, the rare rs4570625-rs4565946 T-T haplotype was associated with reduced processing speed (n = 193, p = 0.004) and sensorimotor gating (n = 68, p = 0.006) of schizophrenia patients. TPH2 variants and the rs4570625-rs4565946 G-C haplotype did not influence the beneficial response to antipsychotic drugs (n = 210) after four weeks of treatment administering the Positive and Negative Syndrome Scale of Schizophrenia (PANSS). We also investigated the association of the SNPs to treatment response, but did not get significant results. In sum, our results argue for only a minor role of TPH2 in schizophrenia.

Dysequilibrium of neuronal proliferation and apoptosis in a pharmacological animal model of psychosis.

Growing evidence implicates that abnormal stem cell proliferation and neurodegenerative mechanisms may be involved in the pathogenesis of neuropsychiatric disorders including schizophrenia. Here, we studied the underlying pathomechanisms of psychosis. We are employing a translational approach combining in vivo data with supplementary data from an adult neuronal stem cell-derived cell culture model by generating a large number of analytes in our specimens following a multiplexing strategy. In the animal model the NMDA receptor was chronically antagonized by MK-801 at ultralow doses. As a result of this, we were able to demonstrate a roughly twofold increased density of PCNA positive cells in the germinal zone of the dentate gyrus indicating enhanced neuroproliferative activity. In vitro stem cell experiments additionally pointed to this direction showing an increase both in proliferation and neuronal differentiation after MK-801 treatment. These alterations were partially prevented by coapplication of the dopamine receptor antagonist haloperidol. In addition, apoptotic activity assessed by immunohistochemical demonstration of cleaved caspase-3 stainings was unaffected by MK-801 treatment. These observations were largely supported by microarray gene expression analysis, which permits high-throughput multiplexed assessment of expression data from a comprehensive set of genes and showed parallels with data from human post mortem studies. In conclusion, our data support the notion, that abnormal proliferation due to anti-apoptotic mechanisms may represent a factor in the pathogenesis of psychosis. Thus, research on the exact interplay between glutamatergic neurotransmission and neuronal proliferation deserves more attention. This dual in vivo and in vitro strategy described here may prove as a suitable model for addressing complex neuropsychiatric diseases especially when taking advantage of the potential of multiplex technologies not only in diagnostics but also in basic research.