Pediatric Traumatic Brain Injury: Impact on the Developing Brain

Omega-3 Fatty Acids and Traumatic Injury in the Adult and Immature Brain

Background/Objectives: Traumatic brain injury (TBI) can lead to substantial disability and health loss. Despite its importance and impact worldwide, no treatment options are currently available to help protect or preserve brain structure and function following injury. In this review, we discuss the potential benefits of using omega-3 polyunsaturated fatty acids (O3 PUFAs) as therapeutic agents in the context of TBI in the paediatric and adult populations. Methods: Preclinical and clinical research reports investigating the effects of O3 PUFA-based interventions on the consequences of TBI were retrieved and reviewed, and the evidence presented and discussed. Results: A range of animal models of TBI, types of injury, and O3 PUFA dosing regimens and administration protocols have been used in different strategies to investigate the effects of O3 PUFAs in TBI. Most evidence comes from preclinical studies, with limited clinical data available thus far. Overall, research indicates that high O3 PUFA levels help lessen the harmful effects of TBI by reducing tissue damage and cell loss, decreasing associated neuroinflammation and the immune response, which in turn moderates the severity of the associated neurological dysfunction. Conclusions: Data from the studies reviewed here indicate that O3 PUFAs could substantially alleviate the impact of traumatic injuries in the central nervous system, protect structure and help restore function in both the immature and adult brains.

Transient Increases in Alpha Power Relative to Healthy Reference Ranges in Awake Piglets After Repeated Rapid Head Rotations

Background/Objectives: Sports-related concussions are a main cause of cognitive dysfunction and somatic complaints, particularly in youth. While the majority of concussion symptoms resolve within one week, cognitive effects may persist. In this study, we sought to study changes to cognition within this acute time frame. Methods: In this current study, we use an established swine model of traumatic brain injury (TBI) to study the effects of single and repeated head rotations on resting-state electroencephalography (rs-EEG) in awake piglets in the acute (within 7 days) time period after injury. We studied both healthy and experimental groups to (1) establish healthy reference ranges (RRs; N = 23) for one-minute rs-EEG in awake piglets, (2) compare the effects of single (N = 12) and repeated head rotations (N = 13) on rs-EEG, and (3) examine the acute time course (pre-injury and days 1, 4, and 7 post-injury) in animals administered single and repeated head rotations. EEG data were Fourier transformed, and total (1-30 Hz) and relative power in the alpha (8-12 Hz), beta (16.5-25 Hz), delta (1-4 Hz), and theta (4-7.5 Hz) bands were analyzed. Results: Total power and relative alpha, beta, delta, and theta power were consistent measures across days in healthy animals. We found a significant and transient increase in relative alpha power after repeated injury on day 1 in all regions and a rise above the healthy RR in the frontal and left temporal regions. Conclusions: Future studies will expand the study duration to investigate and inform clinical prognoses from acute measurements of rs-EEG.

Engineered Dual Antioxidant Enzyme Complexes Targeting ICAM-1 on Brain Endothelium Reduce Brain Injury-Associated Neuroinflammation

The neuroinflammatory cascade triggered by traumatic brain injury (TBI) represents a clinically important point for therapeutic intervention. Neuroinflammation generates oxidative stress in the form of high-energy reactive oxygen and nitrogen species, which are key mediators of TBI pathology. The role of the blood-brain barrier (BBB) is essential for proper neuronal function and is vulnerable to oxidative stress. Results herein explore the notion that attenuating oxidative stress at the vasculature after TBI may result in improved BBB integrity and neuroprotection. Utilizing amino-chemistry, a biological construct (designated "dual conjugate" for short) was generated by covalently binding two antioxidant enzymes (superoxide dismutase 1 (SOD-1) and catalase (CAT)) to antibodies specific for ICAM-1. Bioengineering of the conjugate preserved its targeting and enzymatic functions, as evaluated by real-time bioenergetic measurements (via the Seahorse-XF platform), in brain endothelial cells exposed to increasing concentrations of hydrogen peroxide or a superoxide anion donor. Results showed that the dual conjugate effectively mitigated the mitochondrial stress due to oxidative damage. Furthermore, dual conjugate administration also improved BBB and endothelial protection under oxidative insult in an in vitro model of TBI utilizing a software-controlled stretching device that induces a 20% in mechanical strain on the endothelial cells. Additionally, the dual conjugate was also effective in reducing indices of neuroinflammation in a controlled cortical impact (CCI)-TBI animal model. Thus, these studies provide proof of concept that targeted dual antioxidant biologicals may offer a means to regulate oxidative stress-associated cellular damage during neurotrauma.

Pediatric Traumatic Brain Injury: Models, Therapeutics, and Outcomes

Pediatric traumatic brain injury (TBI) is a significant healthcare issue, but potential treatments are absent despite robust investigation in several clinical trials. Factors attributed to clinical TBI, such as heterogeneity of injury and single-dose pharmacological treatments as well as timing of administration, may be reasons for the negative studies. Preclinical models of TBI can reduce some of the impediments by highlighting differences in injury depending on injury severity and location and by conducting dose response studies, thus providing better therapeutic targets and pharmacological profiles for clinical use. In this chapter, there were sufficient reports to make comparisons between the models in terms of pathophysiology, behavioral dysfunction, and the efficacy of therapeutic interventions. The models used to date include controlled cortical impact (CCI), weight drop, fluid percussion, and abusive head trauma. Several therapeutics were identified after CCI injury but none in the other models, which underscores the need for studies evaluating the therapies reported after CCI injury as well as novel potential approaches.