Cognitive Impairments Following Traumatic Brain Injury

Regulation of Phosphorylated State of NMDA Receptor by STEP61 Phosphatase after Mild-Traumatic Brain Injury: Role of Oxidative Stress

Traumatic Brain Injury (TBI) mediates neuronal death through several events involving many molecular pathways, including the glutamate-mediated excitotoxicity for excessive stimulation of N-methyl-D-aspartate receptors (NMDARs), producing activation of death signaling pathways. However, the contribution of NMDARs (distribution and signaling-associated to the distribution) remains incompletely understood. We propose a critical role of STEP₆₁ (Striatal-Enriched protein tyrosine phosphatase) in TBI; this phosphatase regulates the dephosphorylated state of the GluN2B subunit through two pathways: by direct dephosphorylation of tyrosine-1472 and indirectly via dephosphorylation and inactivation of Fyn kinase. We previously demonstrated oxidative stress’s contribution to NMDAR signaling and distribution using SOD2^+/− mice such a model. We performed TBI protocol using a controlled frontal impact device using C57BL/6 mice and SOD2^+/− animals. After TBI, we found alterations in cognitive performance, NMDAR-dependent synaptic function (decreased synaptic form of NMDARs and decreased synaptic current NMDAR-dependent), and increased STEP₆₁ activity. These changes are reduced partially with the STEP₆₁-inhibitor TC-2153 treatment in mice subjected to TBI protocol. This study contributes with evidence about the role of STEP₆₁ in the neuropathological progression after TBI and also the alteration in their activity, such as an early biomarker of synaptic damage in traumatic lesions.

The AMPAR Antagonist Perampanel Attenuates Traumatic Brain Injury Through Anti-Oxidative and Anti-Inflammatory Activity

Perampanel is a novel α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) antagonist, approved in over 35 countries as an adjunctive therapy for the treatment of seizures. Recently, it was found to exert protective effects against ischemic neuronal injury in vitro. In the present study, we investigated the potential protective effects of perampanel in a traumatic brain injury (TBI) model in rats. Oral administration with perampanel at a dose of 5 mg/kg exerted no major organ-related toxicities. We found that perampanel significantly attenuated TBI-induced brain edema, brain contusion volume, and gross motor dysfunction. The results of Morris water maze test demonstrated that perampanel treatment also improved cognitive function after TBI. These neuroprotective effects were accompanied by reduced neuronal apoptosis, as evidenced by decreased TUNEL-positive cells in brain sections. Moreover, perampanel markedly inhibited lipid peroxidation and obviously preserved the endogenous antioxidant system after TBI. In addition, enzyme-linked immunosorbent assay (ELISA) was performed at 4 and 24 h after TBI to evaluate the expression of inflammatory cytokines. The results showed that perampanel suppressed the expression of pro-inflammatory cytokines TNF-α and IL-1β, whereas increased the levels of anti-inflammatory cytokines IL-10 and TGF-β1. These data show that the orally active AMPAR antagonist perampanel affords protection against TBI-induced neuronal damage and neurological dysfunction through anti-oxidative and anti-inflammatory activity.

Hydrogen-rich water attenuates brain damage and inflammation after traumatic brain injury in rats

Inflammation and oxidative stress are the two major causes of apoptosis after traumatic brain injury (TBI). Most previous studies of the neuroprotective effects of hydrogen-rich water on TBI primarily focused on antioxidant effects. The present study investigated whether hydrogen-rich water (HRW) could attenuate brain damage and inflammation after traumatic brain injury in rats. A TBI model was induced using a controlled cortical impact injury. HRW or distilled water was injected intraperitoneally daily following surgery. We measured survival rate, brain edema, blood-brain barrier (BBB) breakdown and neurological dysfunction in all animals. Changes in inflammatory cytokines, inflammatory cells and Cho/Cr metabolites in brain tissues were also detected. Our results demonstrated that TBI-challenged rats exhibited significant brain injuries that were characterized by decreased survival rate and increased BBB permeability, brain edema, and neurological dysfunction, while HRW treatment ameliorated the consequences of TBI. HRW treatment also decreased the levels of pro-inflammatory cytokines (TNF-α, IL-1β and HMGB1), inflammatory cell number (Iba1) and inflammatory metabolites (Cho) and increased the levels of an anti-inflammatory cytokine (IL-10) in the brain tissues of TBI-challenged rats. In conclusion, HRW could exert a neuroprotective effect against TBI and attenuate inflammation, which suggests HRW as an effective therapeutic strategy for TBI patients.

Treatment effect versus pretreatment recovery in persons with traumatic brain injury: a study regarding the effectiveness of postacute rehabilitation

OBJECTIVE

To evaluate functional improvement following a traumatic brain injury (TBI) after admission to a postacute treatment facility, focusing on the time since injury and analysis of recovery by degree of impairment at admission.

DESIGN

A retrospective study of patients who received treatment at a postacute rehabilitation facility.

SETTING

Postacute rehabilitation for persons with acquired brain injury that involved transdisciplinary teams.

PATIENTS

Patients (n = 1274) were admitted for treatment less than 5 years after TBI and were assessed on our outcome measures at least 3 times. The patients were then grouped by the time since injury and the severity of impairment at admission.

METHODS

Patients received comprehensive multidisciplinary treatment 5 days per week, 6 hours per day.

MAIN OUTCOME MEASUREMENTS

Function was assessed by using the Pate Environmentally Relevant Program Outcome System (PERPOS) scale at admission, discharge, and approximately every 2 weeks during treatment. By using these assessment scores, the rate and degree of improvement were monitored.

RESULTS

Postacute rehabilitation yielded significant gains in functioning, with 69% of all patients who demonstrated clinically meaningful gains. The time since injury had a significant impact on gains made in rehabilitation (Ftime × time-since-treatment group interaction = 17.75; P < .001), with the 0-3 months post injury group outperforming each other group (P < .001 for each comparison). This effect was statistically significant (P < .001) for each of the 3 severity-at-intake subgroups analyzed but was stronger for the severe (F314 = 9.05) and moderate-to-severe (F425 = 7.32) than for the mild-to-moderate (F533 = 2.95) severity-at-intake groups.

CONCLUSIONS

Postacute rehabilitation is associated with functional gains for individuals with TBI beyond what can be explained by undirected recovery. These findings provide evidence for postacute rehabilitation as effective care after TBI.

The Use of Aesthetic Knowledge in the Management of Brain Injury Patients

A patient's recovery from a brain injury (BI) is unpredictable and requires flexible nursing strategies for each stage of recovery. Empirical knowledge provides a framework for delivering nursing care based on scientific principles. Aesthetic knowledge, including intuition, provides a further opportunity to know and understand BI patients and their responses as they progress along the trajectory of recovery. Incorporating both empirical and aesthetic knowledge into the nursing plan of care for this population affords on opportunity for nurses to help patients and their families negotiate the course of recovery with greater success.

Protective effects of hydrogen-rich saline in a rat model of traumatic brain injury via reducing oxidative stress

BACKGROUND

Hydrogen gas (H(2)) has been considered as a novel antioxidant to selectively reduce the toxic reactive oxygen species (ROS) such as hydroxyl radical (•OH) without affecting the other signal ROS. Our recent study shows that H(2) inhalation is beneficial to traumatic brain injury (TBI) via reducing oxidative stress. In contrast to H(2), hydrogen-rich saline (HS) may be more suitable for clinical application. The present study was designed to investigate whether HS has a protective effect against TBI via reducing oxidative stress in rats.

METHODS

TBI model was induced by controlled cortical impact injury. Different dosages of HS were intraperitoneally administered at 5 min after TBI operation. We then measured the brain edema, blood-brain barrier (BBB) breakdown, neurological dysfunction and injury volume in all animals. In addition, the oxidative products and antioxidant enzymes in brain tissues were detected.

RESULTS

TBI-challenged rats exhibited significant brain injuries characterized by the increase of BBB permeability, brain edema, and lesion volume as well as neurological dysfunction, which were dose-dependently ameliorated by HS treatment. Moreover, we found that HS treatment increased the endogenous antioxidant enzymatic activities and decreased the oxidative product levels in brain tissues of TBI-challenged rats.

CONCLUSION

Hydrogen-rich saline can exert a protective effect against TBI via reducing oxidative stress. Molecular hydrogen may be a more effective therapeutic strategy for TBI patients.

Protective effects of mGluR5 positive modulators against traumatic neuronal injury through PKC-dependent activation of MEK/ERK pathway

Several previous studies utilizing selective pharmacological antagonists have demonstrated that type 5 metabotropic glutamate receptors (mGluR5) are potential therapeutic targets for the treatment of numerous disorders of the central nervous system, but the role of mGluR5 activation in traumatic brain injury (TBI) is not fully understood. Here in an in vitro TBI model, the mGluR5 agonist (RS)-2-chloro-5- hydroxyphenylglycine (CHPG) and the positive allosteric modulators 3-cyano-N-(1,3- diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB) were used to investigate the neuroprotective potency of mGluR5 activation. Data showed that CHPG and CDPPB suppressed the increase of LDH release and caspase-3 activation induced by traumatic neuronal injury in a dose-dependent manner, and the salutary effects were also present when these compounds were added 1 h after injury. Western blot was used to examine the activation of three members of mitogen-activated protein kinases: extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 kinase (p38). CHPG and CDPPB enhanced the activation of ERK after traumatic neuronal injury, and PD98059 and U0126, two selective MEK/ERK inhibitors, partly revised the protective effects. Furthermore, we also investigated the role of protein kinase C (PKC) in CHPG and CDPPB-induced neuroprotection. With the pretreatment of chelerythrine chloride, a PKC inhibitor, the surpressing effects of CHPG and CDPPB on traumatic injury-evoked LDH release and caspase-3 activation were blocked. All of these findings extended the protective role of mGluR5 activation in an in vitro model of TBI and suggested that these protective effects might be mediated by the PKC-dependent activation of MEK/ERK pathway. These results may have important implications for the development of mGluR5 modulators to treat TBI.

Beneficial effects of hydrogen gas in a rat model of traumatic brain injury via reducing oxidative stress

Traumatic brain injury (TBI) is a leading cause of mortality and disability among the young population. It has been shown that hydrogen gas (H(2)) exerts a therapeutic antioxidant activity by selectively reducing hydroxyl radical (OH, the most cytotoxic ROS). Recently, we have found that H(2) inhalation significantly improved the survival rate and organ damage of septic mice. In the present study, we investigated the effectiveness of H(2) therapy on brain edema, blood-brain barrier (BBB) breakdown, neurological dysfunction and injury volume in TBI-challenged rats. In addition, we investigated the effects of H(2) treatment on the changes of oxidative products and antioxidant enzymes in brain tissue of TBI-challenged rats. Hydrogen treatment was given by exposure to 2% H(2) from 5 min to 5h after sham or TBI operation, respectively. Here, we found that TBI-challenged rats showed significant brain injuries characterized by the increase of BBB permeability, brain edema and lesion volume as well as neurological dysfunction, which was significantly attenuated by 2% H(2) treatment. In addition, we found that the decrease of oxidative products and the increase of endogenous antioxidant enzymatic activities in the brain tissue may be associated with the protective effects of H(2) treatment in TBI-challenged rats. The present study supports that H(2) inhalation may be a more effective therapeutic strategy for patients with TBI.

The need to explore the prevalence and treatment of acquired brain injury among persons with serious and persistent mental illnesses

This article highlights the importance of studying the prevalence and treatment of acquired brain injury among persons with serious and persistent mental illnesses. It is likely that the prevalence of acquired brain injury among persons with serious and persistent mental illnesses may be underreported and therefore, treatment may not address symptoms arising from brain injuries. This topic needs to be explored so that persons may participate in treatment that is appropriate to their neurological as well as psychiatric illnesses and so that the clinicians treating these persons may better understand techniques for addressing the needs of a person with an acquired brain injury.

Novel approaches to preventing chemotherapy-induced cognitive dysfunction in breast cancer: the art of the possible

Chemotherapy-induced cognitive dysfunction in women with breast cancer has become an increasingly important clinical issue. To date, little is known about its incidence, exact characteristics, and exact pathophysiology. Likewise, no treatments have been shown to prevent or decrease cognitive changes thought to result from chemotherapy. However, ongoing scientific research might help us understand the mechanisms that will help patients maintain maximal cognitive function. Changes in cognition due to chemotherapy might result from indirect chemical toxicity and oxidative damage, direct injury to neurons, inflammation, or a type of autoimmune response. Based on these potential causes, and based on interventions that have been tested in dementia and Alzheimer's disease, there are a number of potential, novel interventions that could be tested in clinical trials as treatments for chemotherapy-induced cognitive dysfunction. Possible anecdotal strategies to consider include hormonal interventions, antioxidants, monoamine oxidase inhibitors, growth factors, dopamine agonists, cholinesterase inhibitors, antiinflammatory agents, and behavioral interventions