Christoph W Gerth

University of Cologne, Köln, North Rhine-Westphalia, Germany

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Publications (45)

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    [Show abstract] [Hide abstract] ABSTRACT: In previous studies, long-term cannabis use led to alterations of the endocannabinoid system including an increase in CB1 and/or CB2 receptor messenger RNA (mRNA) in blood cells and an increase in the serum level of the endocannabinoid 2-arachidonoyl glycerol. However, in those studies, cannabis use was stopped only few days before testing or not interrupted at all. Therefore, one cannot decide whether the alterations are due to long-term cannabis abuse or are confounded by acute effects of cannabis. Blood was sampled from donors that had smoked marijuana ≥20 times in their lives but had abstained from cannabis for ≥6 months (high-frequency users, HFU) and from controls (cannabis use ≤5 times lifetime). CB1 and CB2 mRNA was determined in peripheral mononuclear blood cells using the reverse transcriptase polymerase chain reaction. Serum anandamide level was assayed using electrospray tandem mass spectrometry. CB2 mRNA was increased by 45 % in HFU when compared to controls, whereas CB1 mRNA did not differ. The anandamide level in HFU exceeded that in controls by 90 %. Tobacco smoking could be excluded as a confounding factor. In conclusion, marijuana users that had smoked marijuana ≥20 times in their lives and stopped cannabis use at least 6 months before the study show an increase in CB2 receptor mRNA in the blood and in serum anandamide level. These alterations resemble those obtained for marijuana smokers that had stopped cannabis use only few days before testing and may be implicated in the pathogenesis of disorders associated with long-term cannabis use.
    Full-text available · Article · May 2014 · Archiv für Experimentelle Pathologie und Pharmakologie
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    File available · Dataset · Mar 2012
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    File available · Dataset · Mar 2012
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    [Show abstract] [Hide abstract] ABSTRACT: Cannabidiol is a component of marijuana that does not activate cannabinoid receptors, but moderately inhibits the degradation of the endocannabinoid anandamide. We previously reported that an elevation of anandamide levels in cerebrospinal fluid inversely correlated to psychotic symptoms. Furthermore, enhanced anandamide signaling let to a lower transition rate from initial prodromal states into frank psychosis as well as postponed transition. In our translational approach, we performed a double-blind, randomized clinical trial of cannabidiol vs amisulpride, a potent antipsychotic, in acute schizophrenia to evaluate the clinical relevance of our initial findings. Either treatment was safe and led to significant clinical improvement, but cannabidiol displayed a markedly superior side-effect profile. Moreover, cannabidiol treatment was accompanied by a significant increase in serum anandamide levels, which was significantly associated with clinical improvement. The results suggest that inhibition of anandamide deactivation may contribute to the antipsychotic effects of cannabidiol potentially representing a completely new mechanism in the treatment of schizophrenia.
    Full-text available · Article · Feb 2012 · Translational Psychiatry
  • Article · Dec 2009 · European Psychiatry
  • Article · Jan 2009 · European Psychiatry
  • F.M. Leweke · C.W. Gerth · B.M. Nolden · [...] · D. Koethe
    Article · Aug 2008 · European Neuropsychopharmacology
  • Article · Nov 2007 · Der Nervenarzt
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    [Show abstract] [Hide abstract] ABSTRACT: Although some insights into the etiology of schizophrenia have been gained, an understanding of the illness at the molecular level remains elusive. Recent advances in proteomic profiling offer great promise for the discovery of markers underlying pathophysiology of diseases. In the present study, we employed two high-throughput proteomic techniques together with traditional methods to investigate cerebrospinal fluid (CSF), brain and peripheral tissues (liver, red blood cells and serum) of schizophrenia patients in an attempt to identify peripheral/surrogate disease markers. The cohorts used to investigate each tissue were largely independent, although some CSF and serum samples were collected from the same patient. To address the major confounding factor of antipsychotic drug treatment, we also included a large cohort of first-onset drug-naive patients. Apolipoprotein A1 (apoA1) showed a significant decrease in expression in schizophrenia patients compared to controls in all five tissues examined. Specifically, using SELDI-TOF mass spectrometry, apoA1 was found decreased in CSF from schizophrenia patients (-35%, P=0.00001) and, using 2D-DIGE, apoA1 was also found downregulated in liver (-30%, P=0.02) and RBCs (-60%, P=0.003). Furthermore, we found a significant reduction of apoA1 in sera of first-onset drug-naive schizophrenia patients using enzyme-linked immunosorbent assay (-18%, P=0.00008) and in two investigations of post-mortem brain tissue using western blot analysis (-35%, P=0.05; -51%, P=0.05). These results show that apoA1 is consistently downregulated in the central nervous system as well as peripheral tissues of schizophrenia patients and may be linked to the underlying disease mechanism.
    Full-text available · Article · Nov 2007 · Molecular Psychiatry
  • [Show abstract] [Hide abstract] ABSTRACT: Previous studies have shown that cerebrospinal fluid (CSF) from schizophrenic patients contains significantly higher levels of the endogenous cannabinoid anandamide than does CSF from healthy volunteers. Moreover, CSF anandamide levels correlated inversely with psychotic symptoms, suggesting that anandamide release in the central nervous system (CNS) may serve as an adaptive mechanism countering neurotransmitter abnormalities in acute psychoses. In the present study we examined whether cannabis use may alter such a mechanism. We used liquid chromatography/mass spectrometry (LC/MS) to measure anandamide levels in serum and CSF from first-episode, antipsychotic-naïve schizophrenics (n=47) and healthy volunteers (n=81). Based on reported patterns of cannabis use and urine delta9-tetrahydrocannabinol (delta9-THC) tests, each subject group was further divided into two subgroups: 'low-frequency' and 'high-frequency' cannabis users (lifetime use < or = 5 times and > 20 times, respectively). Serum delta9-THC was investigated to determine acute use and three patients were excluded from the analysis due to detectable delta9-THC levels in serum. Schizophrenic low-frequency cannabis users (n=25) exhibited > 10-fold higher CSF anandamide levels than did schizophrenic high-frequency users (n=19, p=0.008), healthy low-frequency (n=55, p<0.001) or high-frequency users (n=26, p<0.001). In contrast, no significant differences in serum anandamide levels were found among the four subgroups. CSF anandamide levels and disease symptoms were negatively correlated in both user groups. The results indicate that frequent cannabis exposure may down-regulate anandamide signaling in the CNS of schizophrenic patients, but not of healthy individuals. Thus, our findings suggest that alterations in endocannabinoid signaling might be an important component of the mechanism through which cannabis impacts mental health.
    Article · Aug 2007 · Schizophrenia Research
  • F M Leweke · C W Gerth · D Koethe · [...] · J Klosterkötter
    [Show abstract] [Hide abstract] ABSTRACT: We performed a post marketing surveillance study (PMS study) to reveal the efficacy and tolerability of orally administered quetiapine in the treatment of acute psychosis over a period of up to three weeks. 398 respective inpatients were assessed in 88 psychiatric departments in Germany by use of the Clinical Global Impression Scale (CGI) and the Brief Psychiatric Rating Scale (BPRS) as well as the clinical impression of psychiatric raters. Safety and tolerability were assessed by vital parameters such as blood pressure, hearth rate and weight as well as the clinical impression of the psychiatric raters. In addition, dosing, concomitant and/or previous pharmacotherapies as well as certain aspects of psychiatric and medical history were documented. A significant reduction of psychopathology was found during three weeks of drug treatment. Daily dosages of quetiapine between 400 and 1200 mg were well tolerated with a limited number of adverse and no serious adverse events. Noteworthy, more than 35 % of all patients received and tolerated excellently more than 800 mg of quetiapine per day under naturalistic treatment conditions, well above the approved maximum daily dosage. This study reflects the clinical efficacy and good tolerability of quetiapine under real world treatment conditions and is in line with the results of the controlled clinical trials of phase II and III.
    Article · May 2007 · Fortschritte der Neurologie · Psychiatrie
  • F. Leweke · C. Gerth · D. Koethe · [...] · J. Klosterkötter
    Article · Apr 2007 · Fortschritte der Neurologie · Psychiatrie
  • F. M. Leweke · D. Koethe · C. W. Gerth · [...] · J. Klosterkotter
    Article · Mar 2007 · European Psychiatry
  • [Show abstract] [Hide abstract] ABSTRACT: We developed a new selective liquid chromatography-electrospray ionization-tandem mass spectrometry method for the identification and quantification of anandamide (AEA), an endogenous cannabinoid receptor ligand, and other bioactive fatty acid ethanolamides (FAEs) in biological samples. Detection limit (0.025 pmol for AEA and 0.1 pmol for palmitoylethanolamide (PEA) and oleoylethanolamide (OEA)) and quantification limit (0.2 pmol for AEA and 0.4 pmol for OEA and PEA) were in the high fmol to low pmol range for all analytes. Linear correlations (r(2)=0.99) were observed in the calibration curves for standard AEA over the range of 0.025-25 pmol and for standard PEA and OEA over the range of 0.1-500 pmol. This method provides a time-saving and sensitive alternative to existing methods for the analysis of FAEs in biological samples.
    Article · Mar 2007 · Analytical Biochemistry
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    [Show abstract] [Hide abstract] ABSTRACT: The initial prodromal state of psychosis (IPS) is defined as an early disease stage prior to the onset of overt psychosis characterized by sub-threshold or more unspecific psychiatric symptoms. Little is known regarding the biochemical changes during this period. We investigated the metabolic/proteomic profiles of cerebrospinal fluid (CSF) of first-onset drug naïve paranoid schizophrenia patients (n = 54) and individuals presenting with initial prodromal symptoms (n = 24), alongside healthy volunteers (n = 70) using proton nuclear magnetic resonance ((1)H-NMR) spectroscopy and surface enhanced laser desorption ionization (SELDI) mass spectrometry, respectively. Partial least square discriminant analysis (PLS-DA) showed that 36%/29% of IPS patients displayed proteomic/metabolic profiles characteristic of first-onset, drug naïve schizophrenia, i.e., changes in levels of glucose and lactate as well as changes in a VGF-derived peptide (VGF23-62) and transthyretin protein concentrations. However, only 29% (n = 7) of the investigated IPS patients (who to date have been followed up for up to three years) have so far received a diagnosis of schizophrenia. The presence of biochemical alterations in the IPS group did not correlate with the risk to develop schizophrenia. Our results imply that schizophrenia-related biochemical disease processes can be traced in CSF of prodromal patients. However, the biochemical disturbances identified in IPS patients, at least when measured at a single time point, may not be sufficient to predict clinical outcome.
    Full-text available · Article · Feb 2007 · PLoS ONE
  • Dagmar Koethe · Christoph W Gerth · Miriam A Neatby · [...] · F Markus Leweke
    [Show abstract] [Hide abstract] ABSTRACT: Recent data on alterations of the endogenous cannabinoid system in schizophrenia have raised the question of its functional role in this disease. The psychoactive compound of Cannabis sativa, delta-9-tetrahydrocannabinol (Delta9-THC), has been shown to induce psychotic symptoms, but it is unknown to what extend prodromal states of psychoses are reflected by these experimental approaches. This study compares four groups of subjects: antipsychotic-naïve patients suffering from acute paranoid schizophrenic or schizophreniform psychosis (SZ), patients in the prodromal state (IPS), healthy controls without any pharmacological intervention (HC) and a second group of healthy volunteers who were orally administered synthetic Delta9-THC (Dronabinol) (HC-THC). Neither SZ and IPS nor HC received the experimental drug. All subjects were assessed using the Brief Psychiatric Rating Scale (BPRS) and the Binocular Depth Inversion Illusion Test (BDII). The latter represents a sensitive measure of impaired visual information processing that manifests in various experimental and naturally occurring psychotic states. BDII values were well comparable in SZ, IPS and HC-THC, and all groups differed significantly to HC. The BPRS revealed no significant difference between HC-THC and IPS while both were significantly different from SZ and HC, respectively. Our results suggest that Delta9-THC-induced altered states of consciousness may serve as a useful tool for modeling psychotic disorders, particularly their prodromal states. Furthermore, they provide insight into the perceptual and psychopathological alterations induced by Delta9-THC, which is essential for the understanding of the pro-psychotic effects of herbal cannabis preparations with highly enriched Delta9-THC content.
    Article · Jan 2007 · Schizophrenia Research
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    [Show abstract] [Hide abstract] ABSTRACT: Psychosis is a severe mental condition that is characterized by a loss of contact with reality and is typically associated with hallucinations and delusional beliefs. There are numerous psychiatric conditions that present with psychotic symptoms, most importantly schizophrenia, bipolar affective disorder, and some forms of severe depression referred to as psychotic depression. The pathological mechanisms resulting in psychotic symptoms are not understood, nor is it understood whether the various psychotic illnesses are the result of similar biochemical disturbances. The identification of biological markers (so-called biomarkers) of psychosis is a fundamental step towards a better understanding of the pathogenesis of psychosis and holds the potential for more objective testing methods. Surface-enhanced laser desorption ionization mass spectrometry was employed to profile proteins and peptides in a total of 179 cerebrospinal fluid samples (58 schizophrenia patients, 16 patients with depression, five patients with obsessive-compulsive disorder, ten patients with Alzheimer disease, and 90 controls). Our results show a highly significant differential distribution of samples from healthy volunteers away from drug-naïve patients with first-onset paranoid schizophrenia. The key alterations were the up-regulation of a 40-amino acid VGF-derived peptide, the down-regulation of transthyretin at approximately 4 kDa, and a peptide cluster at approximately 6,800-7,300 Da (which is likely to be influenced by the doubly charged ions of the transthyretin protein cluster). These schizophrenia-specific protein/peptide changes were replicated in an independent sample set. Both experiments achieved a specificity of 95% and a sensitivity of 80% or 88% in the initial study and in a subsequent validation study, respectively. Our results suggest that the application of modern proteomics techniques, particularly mass spectrometric approaches, holds the potential to advance the understanding of the biochemical basis of psychiatric disorders and may in turn allow for the development of diagnostics and improved therapeutics. Further studies are required to validate the clinical effectiveness and disease specificity of the identified biomarkers.
    Full-text available · Article · Dec 2006 · PLoS Medicine
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    Dataset: Table S4
    [Show abstract] [Hide abstract] ABSTRACT: Summary of Potential Peptide/Protein Biomarkers for Four Neurological/Neuropsychiatric Disorders Investigated in This Study (94 KB DOC)
    File available · Dataset · Nov 2006
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    Dataset: Figure S3
    [Show abstract] [Hide abstract] ABSTRACT: Patients with Depression who Presented with Acute Psychotic Symptoms (n = 3) at the Time of Sample Collection Did Not Co-Cluster with Schizophrenia Patients and Did Not Show a Significant Difference when Compared to Non-Psychotic Patients with Depression (1.8 MB TIF)
    File available · Dataset · Nov 2006
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    Dataset: Figure S1
    [Show abstract] [Hide abstract] ABSTRACT: The m/z = 6,800–7,000 Region of CSF Spectra Was under a Strong Influence of Doubly Charged Ions from the Transthyretin Proteins (1.8 MB TIF)
    File available · Dataset · Nov 2006