@article{TaurinesFeketePreussWiedenhoffetal.2022,
  author    = {Taurines, R. and Fekete, S. and Preuss-Wiedenhoff, A. and Warnke, A. and Wewetzer, C. and Plener, P. and Burger, R. and Gerlach, M. and Romanos, M. and Egberts, K. M.},
  title     = {Therapeutic drug monitoring in children and adolescents with schizophrenia and other psychotic disorders using risperidone},
  series = {Journal of Neural Transmission},
  volume    = {129},
  journal   = {Journal of Neural Transmission},
  number    = {5-6},
  doi       = {10.1007/s00702-022-02485-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324833},
  pages     = {689-701},
  year      = {2022},
  abstract  = {Risperidone is commonly used to treat different psychiatric disorders worldwide. Knowledge on dose-concentration relationships of risperidone treatment in children and adolescents with schizophrenia or other psychotic disorders is, however, scarce and no age-specific therapeutic ranges have been established yet. Multicenter data of a therapeutic drug monitoring service were analyzed to evaluate the relationship between risperidone dose and serum concentration of the active moiety (risperidone (RIS) plus its main metabolite 9-hydroxyrisperidone (9-OH-RIS)) in children and adolescents with psychotic disorders. Patient characteristics, doses, serum concentrations and therapeutic outcomes were assessed by standardized measures. The study also aimed to evaluate whether the therapeutic reference range for adults (20-60 ng/ml) is applicable for minors. In the 64 patients (aged 11-18 years) included, a positive correlation between daily dose and the active moiety (RIS\(_{am}\)) concentration was found (r\(_s\) = 0.49, p = 0.001) with variation in dose explaining 24\% (r\(_s\)\(^2\) = 0.240) of the variability in serum concentrations. While the RIS\(_{am}\) concentration showed no difference, RIS as well 9-OH-RIS concentrations and the parent to metabolite ratio varied significantly in patients with co-medication of a CYP2D6 inhibitor. Patients with extrapyramidal symptoms (EPS) had on average higher RIS\(_{am}\) concentrations than patients without (p = 0.05). Considering EPS, the upper threshold of the therapeutic range of RIS\(_{am}\) was determined to be 33 ng/ml. A rough estimation method also indicated a possibly decreased lower limit of the preliminary therapeutic range in minors compared to adults. These preliminary data may contribute to the definition of a therapeutic window in children and adolescents with schizophrenic disorders treated with risperidone. TDM is recommended in this vulnerable population to prevent concentration-related adverse drug reactions.},
  language  = {en}
}
@article{LueffeBauerGiogaetal.2022,
  author    = {L{\"u}ffe, Teresa M. and Bauer, Moritz and Gioga, Zoi and {\"O}zbay, Duru and Romanos, Marcel and Lillesaar, Christina and Drepper, Carsten},
  title     = {Loss-of-Function Models of the Metabotropic Glutamate Receptor Genes Grm8a and Grm8b Display Distinct Behavioral Phenotypes in Zebrafish Larvae (Danio rerio)},
  series = {Frontiers in Molecular Neuroscience},
  volume    = {15},
  journal   = {Frontiers in Molecular Neuroscience},
  issn      = {1662-5099},
  doi       = {10.3389/fnmol.2022.901309},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-277429},
  year      = {2022},
  abstract  = {Members of the family of metabotropic glutamate receptors are involved in the pathomechanism of several disorders of the nervous system. Besides the well-investigated function of dysfunctional glutamate receptor signaling in neurodegenerative diseases, neurodevelopmental disorders (NDD), like autism spectrum disorders (ASD) and attention-deficit and hyperactivity disorder (ADHD) might also be partly caused by disturbed glutamate signaling during development. However, the underlying mechanism of the type III metabotropic glutamate receptor 8 (mGluR8 or GRM8) involvement in neurodevelopment and disease mechanism is largely unknown. Here we show that the expression pattern of the two orthologs of human GRM8, grm8a and grm8b, have evolved partially distinct expression patterns in the brain of zebrafish (Danio rerio), especially at adult stages, suggesting sub-functionalization of these two genes during evolution. Using double in situ hybridization staining in the developing brain we demonstrate that grm8a is expressed in a subset of gad1a-positive cells, pointing towards glutamatergic modulation of GABAergic signaling. Building on this result we generated loss-of-function models of both genes using CRISPR/Cas9. Both mutant lines are viable and display no obvious gross morphological phenotypes making them suitable for further analysis. Initial behavioral characterization revealed distinct phenotypes in larvae. Whereas grm8a mutant animals display reduced swimming velocity, grm8b mutant animals show increased thigmotaxis behavior, suggesting an anxiety-like phenotype. We anticipate that our two novel metabotropic glutamate receptor 8 zebrafish models may contribute to a deeper understanding of its function in normal development and its role in the pathomechanism of disorders of the central nervous system.},
  language  = {en}
}