Effects of advanced age upon astrocyte-specific responses to acute traumatic brain injury in mice
Year: 2020
Type: article
Abstract: BACKGROUND: Older-age individuals are at the highest risk for disability from a traumatic brain injury (TBI). Astrocytes are the most numerous glia in the brain, necessary for brain function, yet there is little known about unique responses of astrocytes in the aged-brain following TBI. METHODS: Our approach examined astrocytes in young adult, 4-month-old, versus aged, 18-month-old mice, at 1, 3, and 7 days post-TBI. We selected these time points to span the critical period in the transition from acute injury to presumably irreversible tissue damage and disability. Two approaches were used to define the astrocyte contribution to TBI by age interaction: (1) tissue histology and morphological phenotyping, and (2) transcriptomics on enriched astrocytes from the injured brain. RESULTS: Aging was found to have a profound effect on the TBI-induced loss of astrocyte function needed for maintaining water transport and edema-namely, aquaporin-4. The aged brain also demonstrated a progressive exacerbation of astrogliosis as a function of time after injury. Moreover, clasmatodendrosis, an underrecognized astrogliopathy, was found to be significantly increased in the aged brain, but not in the young brain. As a function of TBI, we observed a transitory refraction in the number of these astrocytes, which rebounded by 7 days post-injury in the aged brain. Transcriptomic data demonstrated disproportionate changes in genes attributed to reactive astrocytes, inflammatory response, complement pathway, and synaptic support in aged mice following TBI compared to young mice. Additionally, our data highlight that TBI did not evoke a clear alignment with the previously defined "A1/A2" dichotomy of reactive astrogliosis. CONCLUSIONS: Overall, our findings point toward a progressive phenotype of aged astrocytes following TBI that we hypothesize to be maladaptive, shedding new insights into potentially modifiable astrocyte-specific mechanisms that may underlie increased fragility of the aged brain to trauma.
Source: Journal of Neuroinflammation
Institution: University of Kentucky
Language: English
Subfield: Clinical Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,890
Awards: Cell-Specific Actions of IL-1 / IL-1R1 Signaling Following Traumatic Brain Injury, University of Kentucky Alzheimer's Disease Core Center, Involvement of myelin integrity in Alzheimer's disease pathogenesis, Dystrophic functions of aged astrocytes following traumatic brain injury, Kentucky Center for Clinical and Translational Science, University of Kentucky Alzheimer's Disease Research Center
OpenAlex ID: W3015511259