Plasma levels of oxidative stress biomarkers and long-term cognitive performance after severe head injury

Aloe vera Leaf Extract Reduced BBB Permeability and Improved Neurological Results after Traumatic Brain Injury: The Role of Oxidative Stress

Introduction

Recognizing the importance of medicinal plants and the absence of specific medications for traumatic brain injury (TBI) treatment, this study was conducted to evaluate the effects of an aqueous extract of Aloe vera on oxidative stress, blood-brain barrier (BBB) permeability, and neurological scores following TBI.

Materials and Methods

Adult male rats were categorized into five groups: sham, TBI, vehicle, low-dose Aloe vera (LA), and high-dose Aloe vera (HA). We induced diffuse TBI using the Marmaro model and administered the aqueous Aloe vera leaf extract, as well as vehicle, via intraperitoneal injection half an hour after TBI. Neurological outcomes were assessed both before and several hours after TBI. Additionally, oxidative stress factors were measured 24 hr after TBI, and Evans blue content (a BBB permeability index) was determined 5 hr after TBI in both serum and brain.

Results

Both LA and HA reduced the increase in BBB permeability after TBI, with HA having a more pronounced effect than LA. Both Aloe vera doses decreased brain MDA levels, increased brain TAC, and lowered both serum and brain PC levels. The impact of Aloe vera on brain oxidative parameters was more significant than on serum. HA also counteracted the declining effects of TBI on neurological outcomes at 4 and 24 hr post-TBI.

Conclusion

This study suggests that Aloe vera extract may reduce BBB permeability and improve neurological outcomes after TBI by decreasing oxidative factors and increasing antioxidant factors.

Luteinizing Hormone and Testosterone Levels during Acute Phase of Severe Traumatic Brain Injury: Prognostic Implications for Adult Male Patients

Traumatic brain injury (TBI) is a worldwide core public health problem affecting mostly young male subjects. An alarming increase in incidence has turned TBI into a leading cause of morbidity and mortality in young adults as well as a tremendous resource burden on the health and welfare sector. Hormone dysfunction is highly prevalent during the acute phase of severe TBI. In particular, investigation of the luteinizing hormone (LH) and testosterone levels during the acute phase of severe TBI in male has identified a high incidence of low testosterone levels in male patients (36.5-100%) but the prognostic significance of which remains controversial. Two independent studies showed that normal or elevated levels of LH levels earlier during hospitalization are significantly associated with higher mortality/morbidity. The association between LH levels and prognosis was independent of other predictive variables such as neuroimaging, admission Glasgow coma scale, and pupillary reaction. The possible mechanisms underlying this association and further research directions in this field are discussed. Overall, current data suggest that LH levels during the acute phase of TBI might contribute to accurate prognostication and further prospective multicentric studies are required to develop more sophisticated predictive models incorporating biomarkers such as LH in the quest for accurate outcome prediction following TBI. Moreover, the potential therapeutic benefits of modulating LH during the acute phase of TBI warrant investigation.

Brain Region-Specific Histopathological Effects of Varying Trajectories of Controlled Cortical Impact Injury Model of Traumatic Brain Injury

AIMS

Traumatic brain injury (TBI) occurs when the head is impacted by an external force causing either a closed or penetrating head injury through a direct or accelerating impact. In laboratory research, most of the TBI animal models focus on a specific region to cause brain injury, but traumatic injuries in patients do not always impact the same brain regions. The aim of this study was to examine the histopathological effects of different angles of mechanical injury by manipulating the trajectory of the controlled cortical impact injury (CCI) model in adult Sprague-Dawley rats.

METHODS

The CCI model was manipulated as follows: conventional targeting of the frontal cortex, farthest right angle targeting the frontal cortex, closest right angle targeting the frontal cortex, olfactory bulb injury, and cerebellar injury. Three days after TBI, brains were harvested to analyze cortical and hippocampal cell loss, neuroinflammatory response, and neurogenesis via immunohistochemistry.

RESULTS

Results revealed cell death in the M1 region of the cortex across all groups, and in the CA3 area from olfactory bulb injury group. This observed cell death involved upregulation of inflammation as evidenced by rampant MHCII overexpression in cortex, but largely spared Ki-67/nestin neurogenesis in the hippocampus during this acute phase of TBI.

CONCLUSION

These results indicate a trajectory-dependent injury characterized by exacerbation of inflammation and different levels of impaired cell proliferation and neurogenesis. Such multiple brain areas showing varying levels of cell death after region-specific CCI model may closely mimic the clinical manifestations of TBI.

Side of pupillary mydriasis predicts the cognitive prognosis in patients with severe traumatic brain injury

BACKGROUND

Pupils' abnormalities are associated to bad prognosis in traumatic brain injury. We investigated the association between the side of pupil mydriasis and the long-term cognitive performance of patients with severe traumatic brain injury (TBI).

METHODS

We analyzed the cognitive performance of patients admitted at the intensive care unit with isochoric pupils (IP, n = 28), left mydriasis (LM, n = 10), right mydriasis (RM, n = 9) evaluated in mean 2.5 years after the severe TBI and controls (n = 26) matched for age, sex and education level.

RESULTS

Patients and controls had similar scores in the four WAIS-III investigated subtests. In comparison with controls, LM patients had lower scores in Letters and Category Fluency and IP patients in Category Fluency. Among the 10 evaluated memory tests, LM patients had lower scores than controls in eight, RM patients in two and IP in three memory tests. IP and RM were 3.5 to nine times more associated to significant impairment (cognitive scores under the percentile 10 of controls) in six of 16 investigated cognitive tests. LM was six to 15 times more associated to significant impairment in 10 of 16 cognitive tests. The association among the pupil abnormalities and cognitive performances remained significant after the multiple linear regression analysis controlling for age, gender, admission coma Glasgow scale and serum glucose, presence of associated trauma, and cranial computed tomography abnormalities.

CONCLUSION

Side of admission pupil abnormalities may be a useful variable to improve prognostic models for long-term cognitive performance in severe TBI patients.

Validity and screening properties of three depression rating scales in a prospective sample of patients with severe traumatic brain injury

OBJECTIVE

To evaluate the validity and utility of the Hamilton Rating Scale for Depression (HAM-D), Beck Depression Inventory (BDI), and Hospital Anxiety and Depression Scale (HADS) as screening tools for depression after severe traumatic brain injury (TBI).

METHODS

Forty-six consecutive survivors of severe TBI were evaluated at a median of 15 months after injury. Receiver operating characteristic (ROC) analysis was performed using HAM-D, BDI, and HADS as predictors, and the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) as gold standard.

RESULTS

The area under the curve (AUC) for HAM-D was 0.89, and the optimal cutoff point was 7 (sensitivity 92.9%, specificity 78.1%); for the BDI, the AUC was 0.946 and the optimal cutoff point was 14 (sensitivity 92.3%, specificity 96.7%); for the HADS, the AUC was 0.947 and the optimal cutoff point was 9 (sensitivity 100%, specificity 80.7%); and for the HADS depression subscale, the AUC was 0.937 and the optimal cutoff point was 6 (sensitivity 92.9%, specificity 83.9%). There were no statistically significant differences among the AUCs.

CONCLUSION

Our findings support a high validity and utility for the HAM-D, BDI, and HADS as screening tools for depression in patients with severe TBI, without major changes in standard cutoff points.

Perspectives on molecular biomarkers of oxidative stress and antioxidant strategies in traumatic brain injury

Traumatic brain injury (TBI) is frequently associated with abnormal blood-brain barrier function, resulting in the release of factors that can be used as molecular biomarkers of TBI, among them GFAP, UCH-L1, S100B, and NSE. Although many experimental studies have been conducted, clinical consolidation of these biomarkers is still needed to increase the predictive power and reduce the poor outcome of TBI. Interestingly, several of these TBI biomarkers are oxidatively modified to carbonyl groups, indicating that markers of oxidative stress could be of predictive value for the selection of therapeutic strategies. Some drugs such as corticosteroids and progesterone have already been investigated in TBI neuroprotection but failed to demonstrate clinical applicability in advanced phases of the studies. Dietary antioxidants, such as curcumin, resveratrol, and sulforaphane, have been shown to attenuate TBI-induced damage in preclinical studies. These dietary antioxidants can increase antioxidant defenses via transcriptional activation of NRF2 and are also known as carbonyl scavengers, two potential mechanisms for neuroprotection. This paper reviews the relevance of redox biology in TBI, highlighting perspectives for future studies.