Traumatic brain injury: from bench to bedside
- 1Interdisciplinary Laboratory of Medical Research, Faculty of Medicine, Federal University of Minas Gerais, Brazil
- 2Federal University of Minas Gerais, Brazil
- 3University of Texas Health Science Center at Houston, United States
worldwide. It is one of the leading causes of death and disability among children and young adults, and its incidence in the elderly population has been rising (1). Data from the Centers for Disease Control and Prevention (CDC) indicate that each year in the USA 1.7 million people have a TBI, with 1.4 million of these injured individuals treated in emergency departments, leading to around 275,000 hospitalizations and 52,000 fatalities. The cost of TBI in the USA was estimated to be US$ 76.5 billion in 2010, comprising US$ 11.5 billion in direct medical expenses and US$ 64.8 billion with indirect expenses (2). High-quality data from low-and middle-income countries are scarce. In Brazil, it was recorded approximately 125,000 hospital admissions due to TBI per year between the years of 2008 and 2012, an incidence of 65.7 admissions per 100,000 inhabitants per year with a hospital mortality of 5.1/100,000/year (Information Technology Department of the Unified Health System, DATASUS). The average annual cost of these hospital expenses was US$ 70,960,000, with an average cost per admission of US$ 568. More importantly, a reliable quantification of the societal and personal burden caused by TBI in developing countries like Brazil is very difficult to establish due to inadequate standardization and incomplete capture of data on the incidence and outcome of brain injury (3).Motor and cognitive deficits are well-known sequelae of TBI, contributing to longterm functional impairment and decrease in quality of life . Over the past years, studies have shown that behavioral or psychiatric disorders, specially depression and anxiety, also represent a significant source of distress in TBI patients . The prevalence of psychiatric diagnoses in these patients is much higher than in the general population, and up to 45% of them presents more than one psychiatric disorder. The detection and management of neuropsychiatric phenomena affects important decisions that will set the pace for treatment and increase the likelihood of successful rehabilitation . Accordingly, a careful assessment of neuropsychiatric disorders is essential in TBI.Although molecular and cellular mechanisms involved in TBI pathophysiology are not fully understood, a growing body of evidence supports the involvement of a wide range of pathways including inflammatory response, oxidative stress and excitotoxicity, that are associated with cognitive, motor, and behavioral outcomes (7)(8)(9)(10)(11)(12)(13). For instance, TBI induces a complex inflammatory response characterized by fast proliferation and migration of, respectively, brain resident immune cells (microglia) and circulating monocytes to the lesion site, with consequent production of inflammatory mediators that influence neuronal activity (7,12). Microglial cells remain activated for weeks, months or even years following a TBI event, which has been associated with increased expression of inflammatory cytokines, such as IL-1β and TNF, and long-term cognitive dysfunction (8)(9)(10)(11). Therefore, TBI treatment should not focus only in the acute phase of the traumatic event but also on chronic processes that may influence the development of TBI long-term cognitive and behavioral changes (9,14).Currently, there is no treatment that prevents or minimizes TBI neurological and psychiatric sequelae. The understanding of the mechanisms underlying TBI pathophysiology may pave the way for the identification of biomarkers and potential therapeutic targets that ultimately will lead to efficacious therapeutic strategies (15).This Research Topic gathers a set of seven studies in an interdisciplinary platform that addresses potential cellular and molecular mechanisms underlying TBI neuropsychiatry outcomes and potential therapeutic strategies. This Research topic also highlights TBIassociated cognitive and behavioral changes in different populations as well as the continuing effort to identify predictors of TBI related mortality. We hope that this Research Topic might contribute to advance the understanding of such a complex and multifaceted field. We are very grateful to the different groups who submitted their scientific findings to this issue, and to the reviewers who kindly provided their time, effort and experience to improve the quality of each study.ASM: conception, drafting the work, revising it and final approval of the version to be published. LCS and ALT: conception, revising the work critically for important intellectual content and final approval of the version to be published.The authors declare that there is no conflict of interest regarding the publication of this Research Topic.
Keywords: Traumatic Brain Injury, Cognition, Anxiety, Depression, Inflammation
Received: 03 Oct 2019;
Accepted: 31 Oct 2019.
Copyright: © 2019 Miranda, de Souza and Teixeira. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Aline S. Miranda, Interdisciplinary Laboratory of Medical Research, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil, email@example.com