Astrocytic Hypertrophy in Anterior Cingulate White Matter of Depressed Suicides

McGill Group for Suicide Studies, Department of Neurology and Neurosurgery, Douglas Mental Health University Institute, McGill University, Verdun, Québec, Canada.
Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology (Impact Factor: 7.05). 08/2011; 36(13):2650-8. DOI: 10.1038/npp.2011.154
Source: PubMed


Increasing evidence suggests that cortical astrocytic function is disrupted in mood disorders and suicide. The fine neuroanatomy of astrocytes, however, remains to be investigated in these psychiatric conditions. In this study, we performed a detailed morphometric analysis of 3D-reconstructed gray and white matter astrocytes in Golgi-impregnated anterior cingulate cortex (ACC) samples from depressed suicides and matched controls. Postmortem ACC samples (BA24) from 10 well-characterized depressed suicides and 10 matched sudden-death controls were obtained from the Quebec Suicide Brain Bank. Golgi-impregnated protoplasmic astrocytes (gray matter, layer VI) and fibrous astrocytes (adjacent white matter) were reconstructed, and their morphometric features were analyzed using the Neurolucida software. For each cell, the soma size as well as the number, length, and branching of processes were determined. The densities of thorny protrusions found along the processes of both astrocytic subtypes were also determined. Protoplasmic astrocytes showed no significant difference between groups for any of the quantified parameters. However, fibrous astrocytes had significantly larger cell bodies, as well as longer, more ramified processes in depressed suicides, with values for these parameters being about twice as high as those measured in controls. These results provide the first evidence of altered cortical astrocytic morphology in mood disorders. The presence of hypertrophic astrocytes in BA24 white matter is consistent with reports suggesting white matter alterations in depression, and provides further support to the neuroinflammatory theory of depression.

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Available from: Susana G Torres-Platas, Sep 29, 2014
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    • "Cells were sampled throughout the cortical thickness, but since no noticeable difference was seen between layers, laminar distributions were not recorded. Cells were traced, reconstructed, and their morphometric features characterized as previously described [44]. In brief, under a 100× (Numerical aperture 1.4) oil immersion objective (Olympus BX51 light microscope, Olympus America Inc., Richmond Hill, On, Canada) processes were analyzed in three dimensions within single sections using a computer-based tracing system (Neurolucida v. 8.10.2, "
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    • "As already mentioned, we found that injection of Aβ peptide into the hippocampus caused hypertrophy of the astrocytes in the damaged tissue. Hypertrophic astrocytes have been observed in patients with pathological conditions such as Alzheimer’s [45] and AIDS [46], and in depressed suicide subjects [47]. In studies thus far, morphometric analysis of astrogliosis has been performed on 2D photographs that only measure a fraction of a cell. "
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    • "We found that in the setting of SIB, cortical gray and white matter astrocytes in the frontal cortex of rhesus macaques show marked atrophy in process length, number, volume, and complexity. Increased cell body area, number of nodes and increased process length in white matter have recently been observed in astrocytes of depressed suicides [17]. We were therefore intrigued to discover that astrocytes in macaques with SIB were noted to have reduced numbers of tips, nodes, arbor length and volume in both grey and white matter indicating subtle changes in morphometrics. "
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