A subtype of microglia is defined by the morphological appearance of the cells as rod-shaped. Little is known about this intriguing cell type, as there are only a few case reports describing rod-shaped microglia in the neuropathological literature. Rod-shaped microglia were shown recently to account for a substantial proportion of the microglia cells in the hippocampus of both demented and cognitively intact aged individuals. We hypothesized that aging could be a defining feature in the occurrence of rod-shaped microglia. To test this hypothesis, two independent series of autopsy cases (total n=168 cases), which covered the adult lifespan from 20 – 100+ years old, were included in the study. The presence or absence of rod-shaped microglia was scored on IBA1 immunohistochemically stained slides for the hippocampus and cortex. We found that age was one of the strongest determinants for the presence of rod-shaped microglia in the hippocampus and the cortex. We found no association with the presence of rod-shaped microglia and a self-reported history of a TBI. Alzheimer’s disease related pathology was found to influence the presence of rod-shaped microglia, but only in the parietal cortex and not in the hippocampus or temporal cortex. Future studies are warranted to determine the functional relevance of rod-shaped microglia in supporting the health of neurons in the aged brain, and the signaling processes that regulate the formation of rod-shaped microglia.
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Research reported in this publication was supported by National Institutes of Health under award numbers P30 AG028383, R00 AG044445.
Bachstetter, Adam D.; Ighodaro, Eseosa T.; Hassoun, Yasmin; Aldeiri, Danah; Neltner, Janna H.; Patel, Ela; Abner, Erin L.; and Nelson, Peter T., "Rod-Shaped Microglia Morphology Is Associated with Aging in 2 Human Autopsy Series" (2017). Spinal Cord and Brain Injury Research Center Faculty Publications. 28.