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Orr TJ, Lesha E, Kramer AH, Cecia A, Dugan JE, Schwartz B, Einhaus SL. Traumatic Brain Injury: A Comprehensive Review of Biomechanics and Molecular Pathophysiology. World Neurosurg 2024; 185:74-88. [PMID: 38272305 DOI: 10.1016/j.wneu.2024.01.084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/14/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
Traumatic brain injury (TBI) is a critical public health concern with profound consequences for affected individuals. This comprehensive literature review delves into TBI intricacies, encompassing primary injury biomechanics and the molecular pathophysiology of the secondary injury cascade. Primary TBI involves a complex interplay of forces, including impact loading, blast overpressure, and impulsive loading, leading to diverse injury patterns. These forces can be categorized into inertial (e.g., rotational acceleration causing focal and diffuse injuries) and contact forces (primarily causing focal injuries like skull fractures). Understanding their interactions is crucial for effective injury management. The secondary injury cascade in TBI comprises multifaceted molecular and cellular responses, including altered ion concentrations, dysfunctional neurotransmitter networks, oxidative stress, and cellular energy disturbances. These disruptions impair synaptic function, neurotransmission, and neuroplasticity, resulting in cognitive and behavioral deficits. Moreover, neuroinflammatory responses play a pivotal role in exacerbating damage. As we endeavor to bridge the knowledge gap between biomechanics and molecular pathophysiology, further research is imperative to unravel the nuanced interplay between mechanical forces and their consequences at the molecular and cellular levels, ultimately guiding the development of targeted therapeutic strategies to mitigate the debilitating effects of TBI. In this study, we aim to provide a concise review of the bridge between biomechanical processes causing primary injury and the ensuing molecular pathophysiology of secondary injury, while detailing the subsequent clinical course for this patient population. This knowledge is crucial for advancing our understanding of TBI and developing effective interventions to improve outcomes for those affected.
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Affiliation(s)
- Taylor J Orr
- College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
| | - Emal Lesha
- Department of Neurological Surgery, University of Tennessee Health Science Center, Memphis, Tennessee; Semmes Murphey Clinic, Memphis, Tennessee
| | - Alexandra H Kramer
- College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Arba Cecia
- School of Medicine, Loyola University Chicago, Chicago, Illinois
| | - John E Dugan
- College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Barrett Schwartz
- Department of Neurological Surgery, University of Tennessee Health Science Center, Memphis, Tennessee; Semmes Murphey Clinic, Memphis, Tennessee
| | - Stephanie L Einhaus
- Department of Neurological Surgery, University of Tennessee Health Science Center, Memphis, Tennessee; Semmes Murphey Clinic, Memphis, Tennessee
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O'Connell CJ, Reeder EL, Hymore JA, Brown RS, Notorgiacomo GA, Collins SM, Gudelsky GA, Robson MJ. Transcriptomic dynamics governing serotonergic dysregulation in the dorsal raphe nucleus following mild traumatic brain injury. Exp Neurol 2024; 374:114695. [PMID: 38246304 DOI: 10.1016/j.expneurol.2024.114695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/15/2023] [Accepted: 01/18/2024] [Indexed: 01/23/2024]
Abstract
Mild traumatic brain injury (mTBI) is a leading cause of disability in the United States, with neuropsychiatric disturbances such as depression, anxiety, PTSD, and social disturbances being common comorbidities following injury. The molecular mechanisms driving neuropsychiatric complications following neurotrauma are not well understood and current FDA-approved pharmacotherapies employed to ameliorate these comorbidities lack desired efficacy. Concerted efforts to understand the molecular mechanisms of and identify novel drug candidates for treating neurotrauma-elicited neuropsychiatric sequelae are clearly needed. Serotonin (5-HT) is linked to the etiology of neuropsychiatric disorders, however our understanding of how various forms of TBI directly affect 5-HT neurotransmission is limited. 5-HT neurons originate in the raphe nucleus (RN) of the midbrain and project throughout the brain to regulate diverse behavioral phenotypes. We hypothesize that the characterization of the dynamics governing 5-HT neurotransmission after injury will drive the discovery of novel drug targets and lead to a greater understanding of the mechanisms associated with neuropsychiatric disturbances following mild TBI (mTBI). Herein, we provide evidence that closed-head mTBI alters total DRN 5-HT levels, with RNA sequencing of the DRN revealing injury-derived alterations in transcripts required for the development, identity, and functional stability of 5-HT neurons. Further, using gene ontology analyses combined with immunohistological analyses, we have identified a novel mechanism of transcriptomic control within 5-HT neurons that may directly influence 5-HT neuron identity/function post-injury. These studies provide molecular evidence of injury-elicited 5-HT neuron dysregulation, data which may expedite the identification of novel therapeutic targets to attenuate TBI-elicited neuropsychiatric sequelae.
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Affiliation(s)
- Christopher J O'Connell
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA
| | - Evan L Reeder
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA
| | - Jacob A Hymore
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA
| | - Ryan S Brown
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA
| | | | - Sean M Collins
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA
| | - Gary A Gudelsky
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA; Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Matthew J Robson
- University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, OH, USA; Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Allen J, Dames SS, Foldi CJ, Shultz SR. Psychedelics for acquired brain injury: a review of molecular mechanisms and therapeutic potential. Mol Psychiatry 2024; 29:671-685. [PMID: 38177350 DOI: 10.1038/s41380-023-02360-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 11/24/2023] [Accepted: 12/01/2023] [Indexed: 01/06/2024]
Abstract
Acquired brain injury (ABI), such as traumatic brain injury and stroke, is a leading cause of disability worldwide, resulting in debilitating acute and chronic symptoms, as well as an increased risk of developing neurological and neurodegenerative disorders. These symptoms can stem from various neurophysiological insults, including neuroinflammation, oxidative stress, imbalances in neurotransmission, and impaired neuroplasticity. Despite advancements in medical technology and treatment interventions, managing ABI remains a significant challenge. Emerging evidence suggests that psychedelics may rapidly improve neurobehavioral outcomes in patients with various disorders that share physiological similarities with ABI. However, research specifically focussed on psychedelics for ABI is limited. This narrative literature review explores the neurochemical properties of psychedelics as a therapeutic intervention for ABI, with a focus on serotonin receptors, sigma-1 receptors, and neurotrophic signalling associated with neuroprotection, neuroplasticity, and neuroinflammation. The promotion of neuronal growth, cell survival, and anti-inflammatory properties exhibited by psychedelics strongly supports their potential benefit in managing ABI. Further research and translational efforts are required to elucidate their therapeutic mechanisms of action and to evaluate their effectiveness in treating the acute and chronic phases of ABI.
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Affiliation(s)
- Josh Allen
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Shannon S Dames
- Psychedelic-Assisted Therapy Post-Graduate Program, Health Sciences and Human Services, Vancouver Island University, Nanaimo, BC, Canada
| | - Claire J Foldi
- Department of Physiology, Monash University, Clayton, VIC, Australia
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Sandy R Shultz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.
- Centre for Trauma and Mental Health Research, Health Sciences and Human Services, Vancouver Island University, Nanaimo, BC, Canada.
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O’Connell CJ, Brown RS, Peach TM, Traubert OD, Schwierling HC, Notorgiacomo GA, Robson MJ. Strain in the Midbrain: Impact of Traumatic Brain Injury on the Central Serotonin System. Brain Sci 2024; 14:51. [PMID: 38248266 PMCID: PMC10813794 DOI: 10.3390/brainsci14010051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024] Open
Abstract
Traumatic brain injury (TBI) is a pervasive public health crisis that severely impacts the quality of life of affected individuals. Like peripheral forms of trauma, TBI results from extraordinarily heterogeneous environmental forces being imparted on the cranial space, resulting in heterogeneous disease pathologies. This has made therapies for TBI notoriously difficult to develop, and currently, there are no FDA-approved pharmacotherapies specifically for the acute or chronic treatment of TBI. TBI is associated with changes in cognition and can precipitate the onset of debilitating psychiatric disorders like major depressive disorder (MDD), generalized anxiety disorder (GAD), and post-traumatic stress disorder (PTSD). Complicating these effects of TBI, FDA-approved pharmacotherapies utilized to treat these disorders often fail to reach the desired level of efficacy in the context of neurotrauma. Although a complicated association, decades of work have linked central serotonin (5-HT) neurotransmission as being involved in the etiology of a myriad of neuropsychiatric disorders, including MDD and GAD. 5-HT is a biogenic monoamine neurotransmitter that is highly conserved across scales of biology. Though the majority of 5-HT is isolated to peripheral sites such as the gastrointestinal (GI) tract, 5-HT neurotransmission within the CNS exerts exquisite control over diverse biological functions, including sleep, appetite and respiration, while simultaneously establishing normal mood, perception, and attention. Although several key studies have begun to elucidate how various forms of neurotrauma impact central 5-HT neurotransmission, a full determination of precisely how TBI disrupts the highly regulated dynamics of 5-HT neuron function and/or 5-HT neurotransmission has yet to be conceptually or experimentally resolved. The purpose of the current review is, therefore, to integrate the disparate bodies of 5-HT and TBI research and synthesize insight into how new combinatorial research regarding 5-HT neurotransmission and TBI may offer an informed perspective into the nature of TBI-induced neuropsychiatric complications.
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Affiliation(s)
- Christopher J. O’Connell
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; (C.J.O.); (R.S.B.); (T.M.P.)
| | - Ryan S. Brown
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; (C.J.O.); (R.S.B.); (T.M.P.)
| | - Taylor M. Peach
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; (C.J.O.); (R.S.B.); (T.M.P.)
| | - Owen D. Traubert
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA;
| | - Hana C. Schwierling
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; (C.J.O.); (R.S.B.); (T.M.P.)
| | | | - Matthew J. Robson
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; (C.J.O.); (R.S.B.); (T.M.P.)
- Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
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Jiang Y, Zhou J, Song BL, Wang Y, Zhang DL, Zhang ZT, Li LF, Liu YJ. 5-HT1A receptor in the central amygdala and 5-HT2A receptor in the basolateral amygdala are involved in social hierarchy in male mice. Eur J Pharmacol 2023; 957:176027. [PMID: 37659688 DOI: 10.1016/j.ejphar.2023.176027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 08/12/2023] [Accepted: 08/25/2023] [Indexed: 09/04/2023]
Abstract
Most social animals self-organize into dominance hierarchies that strongly influence their behavior and health. The serotonin (5-HT) system is believed to play an important role in the formation of social hierarchy. 5-HT receptors are abundantly expressed in the amygdala, which is considered as the central node for the perception and learning of social hierarchy. In this study, we assessed the functions of various 5-HT receptor subtypes related to social rank determination in different subregions of the amygdala using the confrontation tube test in mice. We revealed that most adult C57BL/6 J male mice exhibited a linear social rank after a few days of cohousing. The tube test ranks were slightly related to anxiety-like behavioral performance. After the tube test, the amygdala and 5-HT neurons in the dorsal raphe nucleus were activated in lower-rank individuals. Quantitative real-time polymerase chain reaction analysis revealed that despite the high expression of 5-HT1A receptor mRNA in the central amygdala (CeA), 5-HT2A receptor mRNA expression was downregulated in the basolateral amygdala (BLA) in higher-rank individuals. The dominant-subordinate relationship between mouse pairs could be switched via pharmacological modulation of these receptors in CeA and BLA, suggesting that these expression changes are essential for establishing social ranks. Our findings provide novel insights into the divergent functions of 5-HT receptors in the amygdala related to social hierarchy, which is closely related to our health and welfare.
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Affiliation(s)
- Yi Jiang
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China
| | - Jie Zhou
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China
| | - Bai-Lin Song
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China
| | - Yan Wang
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China
| | - Dong-Lin Zhang
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China
| | - Zheng-Tian Zhang
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China
| | - Lai-Fu Li
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China.
| | - Ying-Juan Liu
- Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agriculture, Nanyang Normal University, Nanyang, 473061, China.
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