Pathophysiology of Pediatric Traumatic Brain Injury

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

Long-Term Quality of Life After Pediatric Traumatic Brain Injury Treated in the Intensive Care Unit

BACKGROUND

To examine the long-term health-related quality of life (HRQL) after pediatric traumatic brain injury (TBI) treated in the intensive care unit (ICU).

METHODS

This retrospective cohort study was conducted using data from four university hospital ICUs in Finland. Children aged < 18 years with TBI treated in the ICU during 2003 to 2013 were included. Patients alive at the end of 2020 were sent two different HRQL questionnaires 15/16-dimensional (15D/16D) and RAND-36  and questions regarding chronic diseases, socioeconomical status, and the need for health care support. HRQL was defined as poor when the 15D/16D score total score was below the age- and sex-matched mean population score in Finland minus the minimal clinically important difference.

RESULTS

A total of 150 of 337 (44%) patients responded (n = 144 15D/16D responses). Median follow-up time was 11 years. Seventy patients (49%) had a poor HRQL according to 15D/16D score. Patients with TBI had significantly poorer 15D scores in every dimension when compared with the matched population mean values. A higher Helsinki CT score, mechanical ventilation, and female sex were associated with poor long-term HRQL according to the 15D/16D. Patients with poor 15D/16D scores also needed significantly more health care services and medications and had more comorbidities than patients with normal scores. A poor 15D/16D score was associated with lower socioeconomic status.

CONCLUSIONS

Half of long-term pediatric ICU-treated TBI survivors had poor HRQL 11 years after injury. More severe head computed tomographic findings at admission and female sex associated with poor HRQL.

Blood-Brain Barrier Dysfunction Predicts Microglial Activation After Traumatic Brain Injury in Juvenile Rats

Traumatic brain injury (TBI) disrupts the blood-brain barrier (BBB), which may exacerbate neuroinflammation post-injury. Few translational studies have examined BBB dysfunction and subsequent neuroinflammation post-TBI in juveniles. We hypothesized that BBB dysfunction positively predicts microglial activation and that vulnerability to BBB dysfunction and associated neuroinflammation are dependent on age at injury. Post-natal day (PND)17 and PND35 rats (n = 56) received midline fluid percussion injury or sham surgery, and immunoglobulin-G (IgG) stain was quantified as a marker of extravasated blood in the brain and BBB dysfunction. We investigated BBB dysfunction and the microglial response in the hippocampus, hypothalamus, and motor cortex relative to age at injury and days post-injury (DPI; 1, 7, and 25). We measured the morphologies of ionized calcium-binding adaptor molecule 1-labeled microglia using cell body area and perimeter, microglial branch number and length, end-points/microglial cell, and number of microglia. Data were analyzed using generalized hierarchical models. In PND17 rats, TBI increased levels of IgG compared to shams. Independent of age at injury, IgG in TBI rats was higher at 1 and 7 DPI, but resolved by 25 DPI. TBI activated microglia (more cells and fewer end-points) in PND35 rats compared to respective shams. Independent of age at injury, TBI induced morphological changes indicative of microglial activation, which resolved by 25 DPI. TBI rats had fewer cells and end-points per cell at 1 and 7 DPI than 25 DPI. Independent of TBI, PND17 rats had larger, more activated microglia than PND35 rats; PND17 TBI rats had larger cell body areas and perimeters than PND35 TBI rats. Importantly, we found support in both ages that IgG quantification predicted microglial activation after TBI. The number of microglia increased with increasing IgG, whereas branch length decreased with increasing IgG, which together indicate microglial activation. Our results suggest that stabilization of the BBB after pediatric TBI may be an important therapeutic strategy to limit neuroinflammation and promote recovery.

Endocannabinoid-mediated rescue of somatosensory cortex activity, plasticity and related behaviors following an early in life concussion

Due to the assumed plasticity of immature brain, early in life brain alterations are thought to lead to better recoveries in comparison to the mature brain. Despite clinical needs, how neuronal networks and associated behaviors are affected by early in life brain stresses, such as pediatric concussions, have been overlooked. Here we provide first evidence in mice that a single early in life concussion durably increases neuronal activity in the somatosensory cortex into adulthood, disrupting neuronal integration while the animal is performing sensory-related tasks. This represents a previously unappreciated clinically relevant mechanism for the impairment of sensory-related behavior performance. Furthermore, we demonstrate that pharmacological modulation of the endocannabinoid system a year post-concussion is well-suited to rescue neuronal activity and plasticity, and to normalize sensory-related behavioral performance, addressing the fundamental question of whether a treatment is still possible once post-concussive symptoms have developed, a time-window compatible with clinical treatment.

Traumatic brain injury and the pathways to cerebral tau accumulation

Tau is a protein that has received national mainstream recognition for its potential negative impact to the brain. This review succinctly provides information on the structure of tau and its normal physiological functions, including in hibernation and changes throughout the estrus cycle. There are many pathways involved in phosphorylating tau including diabetes, stroke, Alzheimer's disease (AD), brain injury, aging, and drug use. The common mechanisms for these processes are put into context with changes observed in mild and repetitive mild traumatic brain injury (TBI). The phosphorylation of tau is a part of the progression to pathology, but the ability for tau to aggregate and propagate is also addressed. Summarizing both the functional and dysfunctional roles of tau can help advance our understanding of this complex protein, improve our care for individuals with a history of TBI, and lead to development of therapeutic interventions to prevent or reverse tau-mediated neurodegeneration.

Associations between School-Behavior-Health Difficulties and Subsequent Injuries among Younger Adolescents: A Population-based Study

Objective: School-behavior-health difficulties (SBHDs) may alter physical/mental capabilities and consequently increase injury risk during daily activities. This study assessed the associations of potential SBHDs and their cumulative number (SBHDcn) with various injury types among younger adolescents. Methods: The study population included 1,559 middle-school adolescents in France (10-18 years, 98% under 16,778 boys and 781 girls). They completed a questionnaire at school-year end collecting socioeconomic features (nationality, family structure, parents' education/occupation/income), school/out-of-school injuries during the school-year (dependent variables), and SBHDs starting before the school-year (low academic performance, alcohol/tobacco/cannabis/other-illicit-drugs use, physical/verbal violence, sexual abuse, perpetrated violence, poor social support, poor general health status, sleep difficulty, depressive symptoms, and suicide attempt). Data were analyzed using logistic regression models and Kaplan-Meier estimates. Results: Injuries were frequent during school-physical/sports-training (10.9%), other-school-training (4.7%), school-free-time (7.4%), out-of-school-sports-activity (16.5%), and traffic (2.2%). Single injury (one injury all injury types combined) and ≥2 injury types affected 23.3 and 7.9% of subjects, respectively. The proportion of adolescents without SBHDs decreased with age more quickly among those with each injury type than among those without injury. Various SBHDs were associated with most injury types, single injury, and ≥2 injury types (sex-age-adjusted odds/relative-risk ratios reaching 11, p < .001). A dose-effect association was found between SBHDcn 1-2/3-5/≥6 and both single injury and ≥2 injury types (sex-age adjusted relative risk ratios reaching 12.66, p < .001, vs. SBHDcn = 0). Socioeconomic features had a moderate confounding role in these associations. Conclusions: SBHDs strongly predict injuries among adolescents. Our findings may inform healthcare providers about their prominent role in detecting/reducing SBHDs and injuries.

Epidemiological study of paediatric traumatic brain injury in Brazil

Background

Traumatic brain injury (TBI) has a high economic and social impact on the family dynamics, particularly among children. High-quality and comprehensive epidemiological studies about TBI in this population are limited worldwide, specifically in Latin America. Therefore, this study aimed to elucidate the epidemiology of TBI among children in Brazil and its effects on the public health system.

Methods

This epidemiological (cohort) retrospective study collected data from the Brazilian healthcare database between 1992 and 2021.

Results

The mean annual volume of hospital admission (HA) due to TBI in Brazil was 29,017. Moreover, the incidence of TBI in the paediatric population was 45.35 admissions per 100,000 inhabitants/year. Furthermore, approximately 941 paediatric hospital deaths per year were caused by TBI, with an in-hospital lethality rate of 3.21%. The average annual financial transfer for TBI was 12,376,628 USD, and the mean cost per admission was 417 USD. In addition, the mean length of hospital stay was 4.2 days. Notably, the length of stay in the hospital was longer among males, Afro-Brazilians patients and individuals aged 15-19 years.

Conclusion

Paediatric TBI is an important public health issue worldwide with high social and economic costs. The incidence of paediatric TBI in Brazil is similar to that in developing countries. Moreover, male predominance (2.3:1) was observed in relation paediatric TBI. Notably, during the pandemic, the incidence of paediatric HA has decreased. To the best of our knowledge, this is the first epidemiological study that specifically evaluates paediatric TBI in Latin America.

Post-Concussive Symptoms in Preschool Children up to Three Months Post-Injury

BACKGROUND AND AIMS

Post-concussive symptoms (PCS) are central to the assessment and management of mild traumatic brain injury (mTBI); however, this remains poorly understood in children aged ≤5 years. The study aimed to explore individual PCS, pattern of parents' PCS report over time, proportion of symptomatic children, and variables associated with parents' report of PCS in their preschool child after a mTBI.

METHODS

Children aged 2-5 years with either a mTBI (n=13) or limb injury (n=6) were recruited from the emergency department (ED). Parent ratings of child PCS were assessed at ED presentation, at one month, and at three months post-injury. Injury (e.g. injury group, pain), child (e.g. pre-existing behavior, symptoms), and parent (e.g. parental stress, education) characteristics were considered when investigating variables that may be relevant to parent report of PCS.

RESULTS

The number of total, physical, and sleep PCS were significantly higher after mTBI, with a significant decrease in physical and sleep PCS over time. The proportion of symptomatic children was comparable between injury groups at each time point. Acute pain and pre-injury symptoms were significantly associated with parents' acute PCS report in the mTBI group. Further research is needed on variables that may be relevant to parents' PCS report at follow-up.

CONCLUSION

Preliminary findings suggest a general trauma response after a mTBI or limb injury, but acute physical and sleep PCS may help differentiate the injury groups. Injury and premorbid child variables may be relevant to parents' report of acute PCS in their child. Additional research is needed to investigate PCS in preschoolers and variables that may predict parents' PCS report.

Electrical stimulation methods and protocols for the treatment of traumatic brain injury: a critical review of preclinical research

BACKGROUND

Traumatic brain injury (TBI) is a leading cause of disabilities resulting from cognitive and neurological deficits, as well as psychological disorders. Only recently, preclinical research on electrical stimulation methods as a potential treatment of TBI sequelae has gained more traction. However, the underlying mechanisms of the anticipated improvements induced by these methods are still not fully understood. It remains unclear in which stage after TBI they are best applied to optimize the therapeutic outcome, preferably with persisting effects. Studies with animal models address these questions and investigate beneficial long- and short-term changes mediated by these novel modalities.

METHODS

In this review, we present the state-of-the-art in preclinical research on electrical stimulation methods used to treat TBI sequelae. We analyze publications on the most commonly used electrical stimulation methods, namely transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), deep brain stimulation (DBS) and vagus nerve stimulation (VNS), that aim to treat disabilities caused by TBI. We discuss applied stimulation parameters, such as the amplitude, frequency, and length of stimulation, as well as stimulation time frames, specifically the onset of stimulation, how often stimulation sessions were repeated and the total length of the treatment. These parameters are then analyzed in the context of injury severity, the disability under investigation and the stimulated location, and the resulting therapeutic effects are compared. We provide a comprehensive and critical review and discuss directions for future research. RESULTS AND CONCLUSION: We find that the parameters used in studies on each of these stimulation methods vary widely, making it difficult to draw direct comparisons between stimulation protocols and therapeutic outcome. Persisting beneficial effects and adverse consequences of electrical simulation are rarely investigated, leaving many questions about their suitability for clinical applications. Nevertheless, we conclude that the stimulation methods discussed here show promising results that could be further supported by additional research in this field.

Developmental and acquired brain injury have opposite effects on finger coordination in children

The ability to coordinate finger forces to dexterously perform tasks develops in children as they grow older. Following brain injury, either developmental (as in cerebral palsy-CP) or acquired (as in traumatic brain injury-TBI), this developmental trajectory will likely be impaired. In this study, we compared finger coordination in a group of children aged 4-12 with CP and TBI to a group of typically developing children using an isometric pressing task. As expected, deficits were observed in functional tests (Jebsen Taylor test of hand function, Box and Block test) for both groups, and children in both groups performed the pressing task less well than the control group. However, differing results were observed between the CP and TBI groups when using the uncontrolled manifold hypothesis to look at the synergy index. This index measures the relative amount of "good" (does not affect the outcome measure) and "bad" (does affect the outcome measure) variability, where in this case the outcome measure is the total force produced by the fingers. While children with CP were more variable in their performance, their synergy index was not significantly different from typically developing children, suggesting the development of compensatory strategies. In contrast, the children following TBI showed performance that got worse as a function of age (i.e., the older children with TBI performed worse than the younger children with TBI). These differences between the groups may be a result of different areas of brain injury typically observed in CP and TBI, and the different amount of time that has passed since the injury.

An Approach to Traumatic Brain Injury-Related Hypopituitarism: Overcoming the Pediatric Challenges

Traumatic brain injury (TBI)-related hypopituitarism is a rare polymorphic complication of brain injury, with very little data, particularly concerning children and teenagers. This is a comprehensive review of the literature regarding this pathology, starting from a new pediatric case. The research was conducted on PubMed and included publications from the last 22 years. We identified nine original studies on the pediatric population (two case reports and seven studies; only four of these seven were prospective studies). TBI-related hypopituitarism is associated with isolated hormonal deficits ranging from 22.5% to 86% and multiple hormonal deficiencies from 5.9% to 50% in the studied pediatric population. Growth hormone (GH) deficiency is most often found, including the form with late occurrence after TBI; it was described as persistent in half of the studies. Thyroid-stimulating hormone (TSH) deficiency is identified as a distant complication following TBI; in all three studies, we identified this complication was found to be permanent. Adrenocorticotropic hormone (ACTH) deficiency did not relate to a certain type of brain trauma, and it was transient in reported cases. Hyperprolactinemia was the most frequent hormonal finding, also occurring late after injury. Central diabetes insipidus was encountered early post-TBI, typically with a transient pattern and did not relate to a particular type of injury. TBI-related hypopituitarism, although rare in children, should be taken into consideration even after a long time since the trauma. A multidisciplinary approach is needed if the patient is to safely overcome any acute condition.

Investigation of clinical findings and CT scan in children with minor head trauma

BACKGROUND

The most common cause of death or severe impairment in children older than one-year-old is traumatic brain injury (TBI). Assessing TBI in children with minor head trauma (MHT) using clinical findings from history-taking and a physical exam is crucial to minimizing unnecessary brain CTs and more accurately predicting TBI. We aimed to evaluate the findings of brain CT scans in children with mild head trauma and their relationship with clinical signs and symptoms to avoid unnecessary interventions in many children with MHT.

METHODS

This cross-sectional-analytical study was performed to evaluate the findings of brain CT scans in children with MHT and their relationship with clinical signs and symptoms that were referred to Poursina Hospital in Rasht in the first half of 2021. Children were divided into two age groups: under two years and 2-12 years, and analyzed separately. Initially, a list containing all demographic information, patients' clinical signs, and symptoms were prepared. The collected data were then analyzed using SPSS software version 26.

RESULTS

According to the results, the mean age of patients was 66.01 months and 88 were boys (56.4%). The most common mechanism of injury was falling from a height. Most patients had isolated head injuries. Among the accompanying injuries, facial injuries were the most common. Among the clinical factors studied, cranial fracture on CT scan and GCS less than 15 were significantly associated with the occurrence of traumatic brain injury on CT scan. In addition, cranial fracture on CT scan, injury severity, and history of vomiting had the highest positive predictive value, respectively.

CONCLUSION

Standard history and clinical examination are sufficient to identify high-risk cases of pediatric head injuries. GCS is the most important risk factor for pediatric MHT. Requesting a CT scan is not recommended without these risk factors.

Traumatic brain injuries in children during COVID-19 pandemic: a national report from northern Iran

BACKGROUND

Evidence suggests that referral cases of traumatic injuries have decreased during the COVID-19 pandemic both in childhood and in adulthood. Still we have very little evidence of referrals due to traumatic brain injury among children during the COVID-19 outbreak. The present study aimed to describe epidemiological and clinical features of pediatric traumatic brain injuries.

METHODS

This cross-sectional study was performed on all patients under 15 years with any evidence of head trauma, referring to Poursina teaching hospital, a referral center for trauma and road accidents in northern Iran. The patients' data were retrospectively collected by reviewing the hospital recorded files and the trauma-specific hospital information system.

RESULTS

Of all 543 pediatric traumatic injuries referred to our hospital during the two pointed periods, 166 had any evidence of head and neck injuries leading to an overall prevalence rate of 30.6%. In this regard, the prevalence rate of head/neck injuries was estimated to be 140 out of 436 within a pre-COVID-19 period (32.1%) and 26 out of 107 within the COVID-19 period (24.3%) indicating no significant difference between the two time periods (P = 0.243). However, assessing the rate of head/neck injuries pre-COVID-19 and COVID-19 periods according to patients' age showed a higher rate of such injuries in pre-COVID-19 as compared to COVID-19 periods in patients aged less than two years (55.6% versus 37.5%, P = 0.013) as well as aged 2 to six years (45.8% versus 30.0%, P = 0.036).

CONCLUSION

The rate of admission of children due to traumatic brain injury during the COVID-19 period does not show a significant change compared to before, and only in children under 6 years of age a decrease in referrals due to brain trauma during the COVID-19 period was observed.

Effect of Hypothermia Therapy on Children with Traumatic Brain Injury: A Meta-Analysis of Randomized Controlled Trials

Hypothermia therapy is a promising therapeutic strategy for traumatic brain injury (TBI); however, some trials have shown that hypothermia therapy has a negative effect on patients with TBI. The treatment of hypothermia in children with TBI remains controversial. We conducted a search of six online databases to validate the literature on comparing hypothermia with normal therapy for children with TBI. Eight randomized controlled trials (514 patients) were included. The meta-analysis indicated that hypothermia therapy may increase the Glasgow Outcome Scale (GOS) scores. However, in terms of improving the rate of complications, intracranial pressure (ICP), mortality, cerebral perfusion pressure (CPP), and length of stay both in hospital as well as pediatric ICU, the difference was not statistically significant. Hypothermia therapy may have clinical advantages in improving the GOS scores in children with TBI compared with normothermic therapy, but hypothermia therapy may have no benefit in improving the incidence of complications, ICP, mortality, CPP, and length of stay both in pediatric ICU as well as hospital. The decision to implement hypothermia therapy for children with TBI depends on the advantages and disadvantages from many aspects and these must be considered comprehensively.

Age-At-Injury Influences the Glial Response to Traumatic Brain Injury in the Cortex of Male Juvenile Rats

Few translational studies have examined how age-at-injury affects the glial response to traumatic brain injury (TBI). We hypothesized that rats injured at post-natal day (PND) 17 would exhibit a greater glial response, that would persist into early adulthood, compared to rats injured at PND35. PND17 and PND35 rats (n = 75) received a mild to moderate midline fluid percussion injury or sham surgery. In three cortical regions [peri-injury, primary somatosensory barrel field (S1BF), perirhinal], we investigated the glial response relative to age-at-injury (PND17 or PND35), time post-injury (2 hours, 1 day, 7 days, 25 days, or 43 days), and post-natal age, such that rats injured at PND17 or PND35 were compared at the same post-natal-age (e.g., PND17 + 25D post-injury = PND42; PND35 + 7D post-injury = PND42). We measured Iba1 positive microglia cells (area, perimeter) and quantified their activation status using skeletal analysis (branch length/cell, mean processes/cell, cell abundance). GFAP expression was examined using immunohistochemistry and pixel analysis. Data were analyzed using Bayesian multivariate multi-level models. Independent of age-at-injury, TBI activated microglia (shorter branches, fewer processes) in the S1BF and perirhinal cortex with more microglia in all regions compared to uninjured shams. TBI-induced microglial activation (shorter branches) was sustained in the S1BF into early adulthood (PND60). Overall, PND17 injured rats had more microglial activation in the perirhinal cortex than PND35 injured rats. Activation was not confounded by age-dependent cell size changes, and microglial cell body sizes were similar between PND17 and PND35 rats. There were no differences in astrocyte GFAP expression. Increased microglial activation in PND17 brain-injured rats suggests that TBI upregulates the glial response at discrete stages of development. Age-at-injury and aging with an injury are translationally important because experiencing a TBI at an early age may trigger an exaggerated glial response.

Traumatic brain injury in women across lifespan

Traumatic brain injury (TBI) is a leading cause of death and disability and a global public health challenge. Every year more than 50 million people suffer a TBI, and it is estimated that 50% of the global population will experience at least one TBI in their lifetime. TBI affects both men and women of all ages, however there is a male bias in TBI research as women have frequently been left out of the literature despite irrefutable evidence of male and female dimorphism in several posttraumatic measures. Women uniquely experience distinct life stages marked by levels of endogenous circulating sex hormones, as well as by physiological changes that are nonexistent in men. In addition to generalized sex-specific differences, a woman's susceptibility, neurological outcomes, and treatment success may vary considerably depending upon when in her lifespan she incurred a traumatic insult. How women impacted by TBI might differ from other women as a factor of age and physiology is not well understood. Furthermore, there is a gap in the knowledge of what happens when TBI occurs in the presence of certain sex-specific and sex-nonspecific variables, such as during pregnancy, with oral contraceptive use, in athletics, in cases of addiction and nicotine consumption, during perimenopause, postmenopause, in frailty, among others. Parsing out how hormone-dependent and hormone-independent lifespan variables may influence physiological, neurodegenerative, and functional outcomes will greatly contribute to future investigative studies and direct therapeutic strategies. The goal of this review is to aggregate the knowledge of prevalence, prognosis, comorbid risk, and response of women incurring TBI at differing phases of lifespan. We strive to illuminate commonalities and disparities among female populations, and to pose important questions to highlight gaps in the field in order to further the endeavor of targeted treatment interventions in a patient-specific manner.

Case report: Lingering post-concussive symptoms in a pediatric patient with presumed Ehlers-Danlos syndrome

BACKGROUND

Connective tissue disorders such as Ehlers-Danlos Syndrome (EDS) can affect collagen and elastin content and structure, including weakening of tissues and vasculature, thus contributing to multiple systemic manifestations. Prior research has successfully focused on peripheral life-threatening manifestations resulting in increased life expectancy, yet clinical observations have warranted investigation of neurological vulnerability, where little is known. Compromised brain tissues and cerebrovasculature could leave these patients vulnerable to mild traumatic brain injury (TBI), with increased severity and duration of post-concussive symptoms and delayed recovery. Clinical reports in adults indicate that higher severity of symptoms after a mild TBI, such as a concussion, can unmask connective tissues disorders leading toward diagnosis. This clinical case report is an example of a pediatric patient with presumed Ehlers-Danlos syndrome who demonstrates increased vulnerability to mild TBI/concussion.

PATIENT

A pediatric female patient presents with unexplained lingering post-concussive symptoms, including trouble sleeping, nausea, frontal headaches, dizziness, visual changes, fatigue, and left-sided weakness more than 6 months post-mild concussion. Patient history of hypermobility, joint derangement, soft tissue mobility, and bruising suggests a potential diagnosis of Ehlers-Danlos syndrome, which may explain symptom severity and length of recovery.

DISCUSSION

This case is the first documented instance of increased vulnerability to TBI in a pediatric patient with presumed Ehlers-Danlos syndrome. It highlights the need for awareness and prevention of injury in this vulnerable patient population, suggests more targeted therapeutic intervention for recovery, and demonstrates the need for preclinical research evaluating the influence of genetic mutations associated with connective tissue disorders on the central nervous system.