Recommendations from the Alzheimer's Disease-Related Dementias Summit 2022
Traumatic Brain Injury (TBI) is a risk factor for Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD). More research is needed to better understand how TBI contributes to the start, development, and progression of AD/ADRD. A panel of TBI and dementia experts attended a virtual meeting in March of 2022, where they re-evaluated the 2019 research recommendations for understanding TBI as an AD/ADRD risk factor and assessed the current progress and research gaps.
At the meeting the panel refined previous recommendations and added new ones., which were organized into four priority areas:
- Promote interdisciplinary collaboration to accelerate progress of clinically meaningful research;
- Characterize how TBI neurodegeneration is associated with different TBI histories in diverse populations;
- Establish infrastructure to support long-term studies both during life and post-mortem;
- Support basic and translational research to reveal AD/ADRD initiation and progression post-TBI.
The synopsis above was a summary of 'Alzheimer's Disease-Related Dementias Summit 2022: National research priorities for the investigation of post-traumatic brain injury Alzheimer's Disease and Related Dementias', full citation below:
Dams-O'Connor K, Awwad HO, Hoffman SW, Pugh MJ, Johnson V, Keene CD, McGavern L, Mukherjee P, Opanashuk L, Umoh N, Sopko G, Zetterberg H.J. Alzheimer's Disease-Related Dementias Summit 2022: National research priorities for the investigation of post-traumatic brain injury Alzheimer's Disease and Related Dementias. Neurotrauma. 2023 Mar 16. doi: 10.1089/neu.2022.0514.
The effect of concussion on nerve fibers in the brain
Concussion is a major health concern and often causes persisting neurological symptoms. Emerging evidence suggests that damage to brain nerve fibers (a.k.a. axons), is a key contributor to its clinical manifestation. Yet, the underpinning molecular changes are not completely understood.
In this study, we aimed to examine the effect of concussion on axons by looking at sodium channels and 'nodes of Ranvier' (the gaps along the myelin sheath on a nerve that are thought to facilitate the rapid conduction of nerve impulses).
Since concussion in humans is non-lethal, we first studied a clinically relevant swine (pig) model of concussion and then determined the clinical relevance of findings after death in human patients with a history of acute traumatic brain injury. We have found that concussion causes a loss of sodium channels at the nodes of Ranvier; a sodium channelopathy observed spanning white matter axons
This newfound phenotype of axonal pathology represents vast disruption of signaling machinery across the brain white matter, which could contribute to the post-concussion neurological dysfunction.
The summary above was written by Hailong Song, the primary author of 'Concussion leads to widespread axonal sodium channel loss and disruption of the node of Ranvier', full citation below:
Song H, McEwan PP, Ameen-Ali KE, Tomasevich A, Kennedy-Dietrich C, Palma A, Arroyo EJ, Dolle JP, Johnson VE, Stewart W, Smith DH. Concussion leads to widespread axonal sodium channel loss and disruption of the node of Ranvier. Acta Neuropathol. 2022 Sep 15. doi: 10.1007/s00401-022-02498-1