The role of the stress system in recovery after traumatic brain injury: A tribute to Bruce S. McEwen

Traumatic brain injury (TBI) represents a major public health concern. Although the majority of individuals that suffer mild-moderate TBI recover relatively quickly, a substantial subset of individuals experiences prolonged and debilitating symptoms. An exacerbated response to physiological and psychological stressors after TBI may mediate poor functional recovery. Individuals with TBI can suffer from poor stress tolerance, impairments in the ability to evaluate stressors, and poor initiation (and cessation) of neuroendocrine stress responses, all of which can exacerbate TBI-mediated dysfunction. Here, we pay tribute to the pioneering neuroendocrinologist Dr. Bruce McEwen by discussing the ways in which his work on stress physiology and allostatic loading impacts the TBI patient population both before and after their injuries. Specifically, we will discuss the modulatory role of hypothalamic-pituitary-adrenal axis responses immediately after TBI and later in recovery. We will also consider the impact of stressors and stress responses in promoting post-concussive syndrome and post-traumatic stress disorders, two common sequelae of TBI. Finally, we will explore the role of early life stressors, prior to brain injuries, as modulators of injury outcomes.

Automated summary

Traumatic brain injury (TBI) is a significant public health concern, with a subset of patients experiencing prolonged and severe symptoms. Exaggerated physiological and psychological stress responses after TBI can hinder functional recovery. This article discusses the impact of stress physiology and allostatic loading, as studied by Dr. Bruce McEwen, on TBI patients both before and after their injuries. It explores the role of the hypothalamic-pituitary-adrenal axis responses in TBI and recovery, as well as the effects of stressors and stress responses in promoting post-concussive syndrome and post-traumatic stress disorders. Early life stressors are also considered as modulators of injury outcomes.