Glia pathology in the prefrontal cortex in alcohol dependence with and without depressive symptoms

Background: Reductions in glial density and enlargement of glial nuclei have been reported in the dorsolateral prefrontal cortex (dlPFC) in mood disorders. In alcohol dependence, often comorbid with depression, it is unclear whether there are changes in the density and size of glial cells in the dlPFC Methods: The packing density and size of Nissl-stained glial cell nuclei were analyzed postmortem in the cortical layers of the dlPFC from 21 control and 17 alcohol-dependent (Alc) subjects without Wernicke or Korsakoff syndromes. Eight Alc subjects had depressive symptoms. The density of glial cells was measured with a three-dimensional cell counting method, and the areal fraction of glial fibrillary acidic protein immunoreactivity (GFAP) was also determined. Results: Glial density was reduced by 11-14% in layers V and VI and in all layers combined in the Alc group. The size of glial nuclei was decreased by 3.2% in Alc subjects. The Alc subjects with depressive symptoms showed the lowest values of density and size. There was no difference in GFAP immunoreactivity, although the lowest values were in the Alc group. Conclusions: Alcohol dependence is characterized by decreases in both density and size of glia in the dlPFC. Glial pathology may be more severe in Alc subjects with depressive symptoms. (C) 2002 Society of Biological Psychiatry.