title: Rod-shaped microglia morphology is associated with aging in 2 human autopsy series.
abstract: 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, 2 independent series of autopsy cases (total n = 168 cases), which covered the adult lifespan from 20 to 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.
authors.affiliation: Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA. Electronic address: adam.bachstetter@uky.edu.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Bachstetter
authors.affiliation: Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
authors.forename: Eseosa T
authors.initials: ET
authors.lastname: Ighodaro
authors.affiliation: Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Hassoun
authors.affiliation: Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Danah
authors.initials: D
authors.lastname: Aldeiri
authors.affiliation: Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Division of Neuropathology, Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA.
authors.forename: Janna H
authors.initials: JH
authors.lastname: Neltner
authors.affiliation: Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
authors.forename: Ela
authors.initials: E
authors.lastname: Patel
authors.affiliation: Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Epidemiology, University of Kentucky, Lexington, KY, USA.
authors.forename: Erin L
authors.initials: EL
authors.lastname: Abner
authors.affiliation: Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Division of Neuropathology, Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000473:pathology; D001344:Autopsy; D002540:Cerebral Cortex / Q000166:cytology; D005260:Female; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D017628:Microglia / Q000473:pathology*; D008875:Middle Aged; D055815:Young Adult
keywords: Aging; Alzheimer's disease; Hippocampus; Microglia activation; Neurodegeneration; Neuroinflammation; Neuropathology; Traumatic brain injury