Remote and Persistent Alterations in Glutamate Receptor Subunit Composition Induced by Spreading Depolarizations in Rat Brain.

Spreading depolarizations (SDs) are massive breakdowns of ion homeostasis in the brain's gray matter and are a necessary pathologic mechanism for lesion development in various injury models. However, injury-induced SDs also propagate into remote, healthy tissue where they do not cause cell death, yet their functional long-term effects are unknown. Here we induced SDs in uninjured cortex and hippocampus of Sprague-Dawley rats to study their impact on glutamate receptor subunit expression after three days. We find that both cortical and hippocampal tissue exhibit changes in glutamate receptor subunit expression, including GluA1 and GluN2B, suggesting that SDs in healthy brain tissue may have a role in plasticity. This study is the first to show prolonged effects of SDs on glutamate signaling and has implications for neuroprotection strategies aimed at SD suppression.

Blunt cerebrovascular injury in the geriatric population.

OBJECTIVE: Blunt cerebrovascular injury (BCVI) is associated with high rates of neurological morbidity and mortality. The detection and management of BCVI has improved with advances in imaging and sensitive screening protocols. Few studies have explored how these injuries specifically affect the geriatric population. The purpose of this retrospective analysis was to investigate the presentation and prognosis of BCVI in the elderly population and to assess its clinical implications in the management of these patients. METHODS: All patients presenting to the University of Cincinnati (UC) level I trauma center between February 2017 and December 2019 were screened for BCVI and entered into the prospectively maintained UC Neurotrauma Registry. Patients with BCVI confirmed by CT angiography underwent retrospective chart reviews to collect information regarding demographics, positive screening criteria, cause of injury, antithrombotic agent, injury location, Denver Grading Scale, hospital and ICU length of stay, and discharge disposition. Patients were divided into geriatric (age ≥ 65 years) and adult (age < 65 years) subgroups. Continuous variables were analyzed using the Student t-test and categorical variables with the Pearson chi-square test. RESULTS: Of 124 patients with BCVI, stratification by age yielded 23 geriatric and 101 adult patients. Injury in the geriatric group was associated with significantly higher mortality (p = 0.0194). The most common cause of injury in the elderly was falls (74%, 17/23; p < 0.0001), whereas motor vehicle accidents were most common in the adult group (38%, 38/100; p = 0.0642). With respect to the location of injury, carotid (p = 0.1171) and vertebral artery (p = 0.6981) injuries did not differ significantly for the geriatric group. The adult population presented more often with Denver grade I injuries (p < 0.0001), whereas the geriatric population presented with grade IV injuries (p = 0.0247). Elderly patients were more likely to be discharged to skilled nursing facilities (p = 0.0403) and adults to home or self-care (p = 0.0148). CONCLUSIONS: This study is the first to characterize BCVI to all cervical and intracranial vessels in the geriatric population. Older age at presentation is significantly associated with greater severity, morbidity, and mortality from injury, with no preference for the particular artery injured. These findings carry important clinical implications for adapting practice in an aging population.