title: Microglia in the dorsal raphe nucleus plays a potential role in both suicide facilitation and prevention in affective disorders.
abstract: An involvement of the central serotonergic system has constantly been reported in the pathogenesis of suicide. The dorsal raphe nucleus (DRN) is the main source of serotonergic innervation of forebrain limbic structures disturbed in suicidal behaviour, in which an abnormal microglia reaction seems to play a role. In our present study, the density of microglia immunostained for the HLA-DR antigen was evaluated in the DRN. These analyses were carried out on paraffin-embedded brains from 24 suicidal and 21 non-suicidal patients; among them, 27 depressed (15 major depressive disorder and 12 bipolar disorder) and 18 schizophrenia (9 residual and 9 paranoid) patients and 22 matched controls without mental disorders. Only the non-suicidal depressed subgroup revealed significantly lower microglial reaction, i.e., a decreased density of HLA-DR positive microglia versus both depressed suicide victims and controls. The effect was not related to antidepressant or antipsychotic medication, as the former correlated positively with microglial density in non-suicidal depressed patients, and the latter had no effect. Moreover, the comparison of these results with previously published data from our workgroup in the same cohort (Krzyżanowska et al. in Psychiatry Res 241:43-46, 4) suggested a positive impact of microglia on ribosomal DNA transcription in DRN neurons in the non-suicidal depressed subgroup, but not in depressed suicidal cases. Therefore, the interaction between microglia and neurons in the DRN may be potentially involved in opposite ways regarding suicide facilitation and prevention in the tested subgroups of depressed patients.
authors.affiliation: Department of Forensic Medicine, Medical University of Gdańsk, ul. Dębowa 23, 80-204, Gdańsk, Poland.
authors.forename: Ralf
authors.initials: R
authors.lastname: Brisch
authors.affiliation: Department of Psychiatry, Otto-von-Guericke-University, Magdeburg, Germany.
authors.forename: Johann
authors.initials: J
authors.lastname: Steiner
authors.affiliation: Institute of Neuropathology, Otto-von-Guericke-University, Magdeburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Mawrin
authors.affiliation: Department of Forensic Medicine, Medical University of Gdańsk, ul. Dębowa 23, 80-204, Gdańsk, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Krzyżanowska
authors.affiliation: Department of Forensic Medicine, Medical University of Gdańsk, ul. Dębowa 23, 80-204, Gdańsk, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Jankowski
authors.affiliation: Department of Forensic Medicine, Medical University of Gdańsk, ul. Dębowa 23, 80-204, Gdańsk, Poland. gost@gumed.edu.pl.|Department of Psychiatry, Otto-von-Guericke-University, Magdeburg, Germany. gost@gumed.edu.pl.|Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany. gost@gumed.edu.pl.
authors.forename: Tomasz
authors.identifier: http://orcid.org/0000-0003-0161-9270
authors.initials: T
authors.lastname: Gos
mesh_terms: D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000473:pathology / Q000523:psychology; D016022:Case-Control Studies; D002452:Cell Count; D003865:Major Depressive Disorder / Q000473:pathology / Q000523:psychology; D065847:Dorsal Raphe Nucleus / Q000473:pathology*; D005260:Female; D006684:HLA-DR Antigens / Q000378:metabolism*; D006801:Humans; D008297:Male; D017628:Microglia / Q000378:metabolism*; D008875:Middle Aged; D019964:Mood Disorders / Q000473:pathology* / Q000523:psychology*; D012559:Schizophrenia / Q000473:pathology; D012565:Schizophrenic Psychology; D018709:Statistics, Nonparametric; D013405:Suicide / Q000523:psychology*
chemical_list: D006684:HLA-DR Antigens
keywords: Dorsal raphe nucleus; Microglia; Postmortem; Suicide