Abnormalities in oligodendrocyte clusters in the inferior parietal cortex in schizophrenia are associated with insight

Abstract

Background and Objectives: Deficits in oligodendrocytes have been consistently reported in the brains of patients with schizophrenia and include alterations in the clustering pattern of oligodendrocytes. Recently it has been shown that oligodendrocyte progenitors proliferate in the adult mammalian brain to form oligodendrocyte clusters (OlC). We previously found a deficit of oligodendrocytes in layer 3 of the inferior parietal lobule (IPL) in subjects with schizophrenia with poor insight into disorder. We hypothesized that the number of OlC might be reduced in schizophrenia subjects with poor insight. Methods: Nissl-stained sections from the Stanley "Parietal Collection" from male schizophrenia subjects (n = 24) that have poor, fair, or good insight into their disorder and normal matched controls (n = 24) were studied. The numerical density (Nv) of OlC was estimated in layer 3 of BA 39 and BA 40 by optical disector method. Results: The Nv of OlC was 23% lower in BA 39 and 30% lower in BA40 in the schizophrenia group compared to the control group (p<0.01). Normal hemispheric differences in the Nv of OlC in BA 39 were absent in the schizophrenia group. The Nv of OlC was significantly decreased in BA39 in the subgroup with poor insight and in BA40 in the subgroups with fair and good insight as compared to controls. In BA40 lower Nv of OlC (-40%, p<0.01) was found in the subgroup with adolescent onset of disease as compared to controls. Conclusions: The deficit of OlC may be associated with altered proliferation and/or maturation of oligodendrocyte progenitors in schizophrenia.