Amphetamine, haloperidol, and experience interact to affect rate of recovery after motor cortex injury

Neurovascular protection in voltage-gated proton channel Hv1 knock-out rats after ischemic stroke: interaction with Na+ /H+ exchanger-1 antagonism

Experimental studies have demonstrated protective effects of NHE‐1 inhibition on cardiac function; however, clinical trials utilizing NHE‐1 antagonists found an increase in overall mortality attributed to thromboembolic strokes. NADPH oxidase‐derived reactive oxygen species (ROS) from microglial cells have been shown to contribute to injury following stroke. We have recently demonstrated that NHE‐1 inhibition enhances ROS in macrophages in a Hv1‐dependent manner. As Hv1 protein is highly expressed in microglia, we hypothesized that “NHE‐1 inhibition may augment neurovascular injury by activating Hv1,” providing a potential mechanism for the deleterious effects of NHE‐1. The goal of this study was to determine whether neurovascular injury and functional outcomes after experimental stroke differed in wild‐type and Hv1 mutant Dahl salt‐sensitive rats treated with an NHE‐1 inhibitor. Stroke was induced using both transient and permanent of middle cerebral artery occlusion (MCAO). Animals received vehicle or NHE‐1 inhibitor KR32568 (2 mg/kg, iv) either 30 min after the start of MCAO or were pretreated (2 mg/kg, iv, day) for 3 days and then subjected to MCAO. Our data indicate that Hv1 deletion confers both neuronal and vascular protection after ischemia. In contrast to our hypothesis, inhibition of NHE‐1 provided further protection from ischemic stroke, and the beneficial effects of both pre‐ and post‐treatment with KR32568 were similar in wild‐type and Hv1^−/− rats. These data indicate that Hv1 activation is unlikely to be responsible for the increased incidence of cerebrovascular events observed in the heart disease patients after NHE‐1 inhibition treatment.

Characterization of brain dystrophins absence and impact in dystrophin-deficient Dmdmdx rat model

Duchenne Muscular Dystrophy (DMD) is a severe muscle-wasting disease caused by mutations in the DMD gene encoding dystrophin, expressed mainly in muscles but also in other tissues like retina and brain. Non-progressing cognitive dysfunction occurs in 20 to 50% of DMD patients. Furthermore, loss of expression of the Dp427 dystrophin isoform in the brain of mdx mice, the most used animal model of DMD, leads to behavioral deficits thought to be linked to insufficiencies in synaptogenesis and channel clustering at synapses. Mdx mice where the locomotor phenotype is mild also display a high and maladaptive response to stress. Recently, we generated Dmd^mdx rats carrying an out-of frame mutation in exon 23 of the DMD gene and exhibiting a skeletal and cardiac muscle phenotype similar to DMD patients. In order to evaluate the impact of dystrophin loss on behavior, we explored locomotion parameters as well as anhedonia, anxiety and response to stress, in Dmd^mdx rats aged from 1.5 to 7 months, in comparison to wild-type (WT) littermates. Pattern of dystrophin expression in the brain of WT and Dmd^mdx rats was characterized by western-blot analyses and immunohistochemistry. We showed that dystrophin-deficient Dmd^mdx rats displayed motor deficits in the beam test, without association with depressive or anxiety-like phenotype. However, Dmd^mdx rats exhibited a strong response to restraint-induced stress, with a large increase in freezings frequency and duration, suggesting an alteration in a functional circuit including the amygdala. In brain, large dystrophin isoform Dp427 was not expressed in mutant animals. Dmd^mdx rat is therefore a good animal model for preclinical evaluations of new treatments for DMD but care must be taken with their responses to mild stress.

Anti-neuroinflammatory effect of 3,4-dihydroxybenzaldehyde in ischemic stroke

BACKGROUND

Increasing evidence from human and animal studies suggests that cerebral ischemic diseases are associated with nerve dysfunction and neuroinflammation. Therefore, alleviating neuroinflammation is a potential way to treat ischemic stroke. Gastrodia elata Blume (GEB) is a traditional Chinese medicine used to treat central nervous system diseases and related conditions, such as vertigo, headache, epilepsy. We have previously shown that GEB has a protective effect in ischemic stroke, and that the underlying mechanism is related to anti-neuroinflammation. 3,4-Dihydroxybenzaldehyde (DBD) is a phenolic component of GEB and may be responsible for the neuroprotective effect of GEB; however, the detailed molecular mechanisms underlying the effects of DBD are unknown.

METHODS

The anti-neuroinflammatory effect of DBD and the potential mechanisms underlying it were assessed. We using a rat model of middle cerebral artery occlusion/reperfusion and lipopolysaccharide-treated BV2 microglial cells.

RESULTS

DBD (10 mg/kg) significantly decreased infarct volume. Additionally, it alleviated neurological deficits in the rats by inhibiting microglia activation. DBD (0.01, 0.1, and 1 μM) also significantly decreased the levels of inflammatory mediators and cytokines such as tumor necrosis factor-α, interleukin (IL)-1β, IL-6, prostaglandin E2. Furthermore, phenotypic analysis of the BV2 cells showed that DBD significantly down-regulated the expression of M1 marker but significantly up-regulated the expression of M2 marker. Moreover, it suppressed nuclear factor (NF)-κB activation and inhibited the phosphorylation of p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase, and extracellular signal-regulated protein kinases 1/2.

CONCLUSIONS

The neuroprotective and anti-inflammatory effects of DBD are associated with selective modulation of microglia polarization and reduction in the production of inflammatory mediators and cytokines through inhibition of MAPK and NF-κB activation. These findings suggest that DBD may be a potential treatment for ischemic stroke and other neuroinflammatory diseases.

Translating concepts of neural repair after stroke: Structural and functional targets for recovery

Stroke is among the most common causes of adult disability worldwide, and its disease burden is shifting towards that of a long-term condition. Therefore, the development of approaches to enhance recovery and augment neural repair after stroke will be critical. Recovery after stroke involves complex interrelated systems of neural repair. There are changes in both structure (at the molecular, cellular, and tissue levels) and function (in terms of excitability, cortical maps, and networks) that occur spontaneously within the brain. Several approaches to augment neural repair through enhancing these changes are under study. These include identifying novel drug targets, implementing rehabilitation strategies, and developing new neurotechnologies. Each of these approaches has its own array of different proposed mechanisms. Current investigation has emphasized both cellular and circuit-based targets in both gray and white matter, including axon sprouting, dendritic branching, neurogenesis, axon preservation, remyelination, blood brain barrier integrity, blockade of extracellular inhibitory signals, alteration of excitability, and promotion of new brain cortical maps and networks. Herein, we review for clinicians recovery after stroke, basic elements of spontaneous neural repair, and ongoing work to augment neural repair. Future study requires alignment of basic, translational, and clinical research. The field continues to grow while becoming more clearly defined. As thrombolysis changed stroke care in the 1990 s and thrombectomy in the 2010 s, the augmentation of neural repair and recovery after stroke may revolutionize care for these patients in the coming decade.

Delayed Administration of Angiotensin II Type 2 Receptor (AT2R) Agonist Compound 21 Prevents the Development of Post-stroke Cognitive Impairment in Diabetes Through the Modulation of Microglia Polarization

A disabling consequence of stroke is cognitive impairment, occurring in 12%-48% of patients, for which there is no therapy. A critical barrier is the lack of understanding of how post-stroke cognitive impairment (PSCI) develops. While 70% of stroke victims present with comorbid diseases such as diabetes and hypertension, the limited use of comorbid disease models in preclinical research further contributes to this lack of progress. To this end, we used a translational model of diabetes to study the development of PSCI. In addition, we evaluated the application of compound 21 (C21), an angiotensin II Type 2 receptor agonist, for the treatment of PSCI by blinding the treatment assignment, setting strict inclusion criteria, and implementing a delayed administration time point. Diabetes was induced by a high-fat diet (HFD) and low-dose streptozotocin (STZ) combination. Control and diabetic rats were subjected to 1 h middle cerebral artery occlusion (MCAO) or sham surgery. Adhesive removal task (ART) and two-trial Y-maze were utilized to test sensorimotor and cognitive function. Three days post-stroke, rats that met the inclusion criteria were administered C21 or vehicle in drinking water at a dose of 0.12 mg/kg/day for 8 weeks. Samples from freshly harvested brains were analyzed by flow cytometry and immunohistochemistry (IHC). Diabetes exacerbated the development of PSCI and increased inflammation and demyelination. Delayed administration of C21 3 days post-stroke reduced mortality and improved sensorimotor and cognitive deficits. It also reduced inflammation and demyelination through modulation of the M1:M2 ratio in the diabetic animals.

Duration of Agitation, Fluctuations of Consciousness, and Associations with Outcome in Patients with Subarachnoid Hemorrhage

BACKGROUND

Agitation is common after subarachnoid hemorrhage (SAH) and may be independently associated with outcomes. We sought to determine whether the duration of agitation and fluctuating consciousness were also associated with outcomes in patients with SAH.

METHODS

We identified all patients with positive Richmond Agitation Sedation Scale (RASS) scores from a prospective observational cohort of patients with SAH from 2011 to 2015. Total duration of agitation was extrapolated for each patient using available RASS scores, and 24-h mean and standard deviation (SD) of RASS scores were calculated for each patient. We also calculated each patient's duration of substantial fluctuation of consciousness, defined as the number of days with 24-h RASS SD > 1. Patients were stratified by 3-month outcome using the modified Rankin scale, and associations with outcome were assessed via logistic regression.

RESULTS

There were 98 patients with at least one positive RASS score, with median total duration of agitation 8 h (interquartile range [IQR] 4-18), and median duration of substantially fluctuating consciousness 2 days (IQR 1-3). Unfavorable 3-month outcome was significantly associated with a longer duration of fluctuating consciousness (odds ratio [OR] per day, 1.51; 95% confidence interval [CI], 1.04-2.20; p = 0.031), but a briefer duration of agitation (OR per hour, 0.94; 95% CI, 0.89-0.99; p = 0.031).

CONCLUSION

Though a longer duration of fluctuating consciousness was associated with worse outcomes in our cohort, total duration of agitation was not, and may have had the opposite effect. Our findings should therefore challenge the intensity with which agitation is often treated in SAH patients.

The diabetes drug semaglutide reduces infarct size, inflammation, and apoptosis, and normalizes neurogenesis in a rat model of stroke

Stroke is a condition with few medical treatments available. Semaglutide, a novel Glucagon-like peptide-1 (GLP-1) analogue, has been brought to the market as a treatment for diabetes. We tested the protective effects of semaglutide against middle cerebral artery occlusion injury in rats. Animals were treated with 10 nmol/kg bw ip. starting 2 h after surgery and every second day for either 1, 7, 14 or 21 days. Semaglutide-treated animals showed significantly reduced scores of neurological impairments in several motor and grip strength tasks. The cerebral infarction size was also reduced, and the loss of neurons in the hippocampal areas CA1, CA3 and the dentate gyrus was much reduced. Chronic inflammation as seen in levels of activated microglia and in the activity of the p38 MAPK - MKK - c-Jun- NF-κB p65 inflammation signaling pathway was reduced. In addition, improved growth factor signaling as shown in levels of activated ERK1 and IRS-1, and a reduction in the apoptosis signaling pathway C-raf, ERK2, Bcl-2/BAX and Caspase-3 was observed. Neurogenesis had also been normalized by the drug treatment as seen in increased neurogenesis (DCX-positive cells) in the dentate gyrus and a normalization of biomarkers for neurogenesis. In conclusion, semaglutide is a promising candidate for re-purposing as a stroke treatment.

Semaphorin 3A Contributes to Secondary Blood-Brain Barrier Damage After Traumatic Brain Injury

Semaphorin 3A (SEMA3A) is a member of the Semaphorins family, a class of membrane-associated protein that participates in the construction of nerve networks. SEMA3A has been reported to affect vascular permeability previously, but its influence in traumatic brain injury (TBI) is still unknown. To investigate the effects of SEMA3A, we used a mouse TBI model with a controlled cortical impact (CCI) device and a blood–brain barrier (BBB) injury model in vitro with oxygen-glucose deprivation (OGD). We tested post-TBI changes in SEMA3A, and its related receptors (Nrp-1 and plexin-A1) expression and distribution through western blotting and double-immunofluorescence staining, respectively. Neurological outcomes were evaluated by modified neurological severity scores (mNSSs) and beam-walking test. We examined BBB damage through Evans Blue dye extravasation, brain water content, and western blotting for VE-cadherin and p-VE-cadherin in vivo, and we examined the endothelial cell barrier through hopping probe ion conductance microscopy (HPICM), transwell leakage, and western blotting for VE-cadherin and p-VE-cadherin in vitro. Changes in miR-30b-5p were assessed by RT-PCR. Finally, the neuroprotective function of miR-30b-5p is measured by brain water content, mNSSs and beam-walking test. SEMA3A expression varied following TBI and peaked on the third day which expressed approximate fourfold increase compared with sham group, with the protein concentrated at the lesion boundary. SEMA3A contributed to neurological function deficits and secondary BBB damage in vivo. Our results demonstrated that SEMA3A level following OGD injury almost doubled than control group, and the negative effects of OGD injury can be improved by blocking SEMA3A expression. Furthermore, the expression of miR-30b-5p decreased approximate 40% at the third day and 60% at the seventh day post-CCI. OGD injury also exhibited an effect to approximately decrease 50% of miR-30b-5p expression. Additionally, the expression of SEMA3A post-TBI is regulated by miR-30b-5p, and miR-30b-5p could improve neurological outcomes post-TBI efficiently. Our results demonstrate that SEMA3A is a significant factor in secondary BBB damage after TBI and can be abolished by miR-30b-5p, which represents a potential therapeutic target.

Environmental enrichment and amantadine confer individual but nonadditive enhancements in motor and spatial learning after controlled cortical impact injury

Environmental enrichment (EE) and amantadine (AMT) enhance motor and cognitive outcome after experimental traumatic brain injury (TBI). However, there are no data on the effects of combining these two therapies. Hence, the aim of the current study was to combine EE and AMT after TBI to determine if their net effect further enhances motor and cognitive performance. Anesthetized adult male rats received either a cortical impact of moderate severity or sham injury and then were randomly assigned to EE or standard (STD) housing and once daily administration of AMT (20 mg/kg; i.p.) or saline vehicle (VEH, 1 mL/kg; i.p.) beginning 24 h after injury for 19 days. Motor and cognitive function were assessed on post-surgical days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. There were no statistical differences among the sham groups regardless of therapy, so the data were pooled. EE, AMT, and their combination (EE + AMT) improved beam-balance, but only EE and EE + AMT enhanced beam-walking. All three treatment paradigms improved spatial learning and memory relative to the VEH-treated STD controls (p < 0.05). No differences were revealed between the EE groups, regardless of treatment, but both were better than the AMT-treated STD group on beam-walking and spatial learning (p < 0.05). Both EE groups equally reduced cortical lesion volume relative to the STD-housed AMT and VEH groups (p < 0.05). The results indicate that although beneficial on their own, EE + AMT do not provide additional benefits after TBI. It is important to note that the lack of additive effects using the current treatment and behavioral protocols does not detract from the benefits of each individual therapy. The findings provide insight for future combination studies.

Safflower Yellow B Protects Brain against Cerebral Ischemia Reperfusion Injury through AMPK/NF-kB Pathway

Inflammation had showed its important role in the pathogenesis of cerebral ischemia and secondary damage. Safflower yellow B (SYB) had neuroprotective effects against oxidative stress-induced brain injuries, but the mechanisms were still largely unknown to us. In this study, we tried to investigate the anti-inflammation effects of SYB and the possible roles of AMPK/NF-κB signaling pathway on these protective effects. In vivo, brain ischemia/reperfusion (I/R) was induced by transient middle cerebral artery occlusion for 2 h and reperfusion for 20 h. Neurofunctional evaluation, infarction area, and brain water contents were measured. Brain injury markers and inflammatory cytokines levels were measured by ELISA kits. In vitro, cell viability, apoptosis, and LDH leakage were measured after I/R in PC12 cells. The expression and phosphorylation levels of AMPK, NF-κB p65, and P-IκB-α in cytoplasm and nuclear were measured by Western blotting. SiRNA experiment was performed to certify the role of AMPK. The results showed SYB reduced infarct size, improved neurological outcomes, and inhibited brain injury after I/R. In vitro test, SYB treatment alleviated PC12 cells injury and apoptosis and inhibited the inflammatory cytokines (IL-1, IL-6, TNF-α, and COX-2) in a dose-dependent manner. SYB treatment induced AMPK phosphorylation and inhibited NF-κB p65 nuclear translocation both in brain and in PC12 cells. Further studies also showed that the inhibition of NF-κB activity of SYB was through AMPK. In conclusion, SYB protected brain I/R injury through reducing expression of inflammatory cytokines and this effect might be partly due to the inhibition of NF-κB mediated by AMPK.

Aripiprazole and environmental enrichment independently improve functional outcome after cortical impact injury in adult male rats, but their combination does not yield additional benefits

Typical antipsychotic drugs (APDs) with D₂antagonistic properties impede functional outcome after experimental traumatic brain injury (TBI) and reduce the effectiveness of environmental enrichment (EE). Here we test the hypothesis that aripiprazole (ARIP), an atypical APD with partial D₂and 5-HT_1Areceptor agonist activities will improve recovery after TBI and when combined with EE will further enhance the benefits. Anesthetized adult male rats received either a controlled cortical impact of moderate severity or sham injury and then were randomly assigned to EE or standard (STD) housing and once daily intraperitoneal injections of ARIP (0.1 mg/kg) or vehicle (VEH; 1.0 mL/kg) beginning 24 h after injury for 19 days. Motor (beam-walking time and beam-walk score) and cognitive (acquisition of spatial learning and memory) outcomes were assessed on post-operative days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. There were no statistical differences among the sham groups, regardless of housing or treatment, so the data were pooled. The SHAM group performed better than all TBI groups on motor and spatial learning (p < 0.05) but did not differ from either EE group on memory retention. Regarding TBI, both EE groups improved motor and cognitive outcomes vs. the VEH-treated STD group (p < 0.05) but did not differ from one another (p > 0.05). The ARIP-treated STD group performed better than the VEH-treated STD group on beam-walk score and spatial learning (p < 0.05), but not beam-walking time or memory retention (p > 0.05). Cortical lesion volume was smaller in all treated groups compared to the TBI + STD + VEH group (p < 0.05). The data replicate previous work and extend the findings by demonstrating that 1) ARIP promotes recovery after TBI, but combining treatments does not yield additional benefits, which is contrary to the hypothesis, and 2) unlike APDs that exhibit D₂ receptor antagonism, ARIP does not impede rehabilitation (i.e., EE).

Intermittent Administration of Haloperidol after Cortical Impact Injury Neither Impedes Spontaneous Recovery Nor Attenuates the Efficacy of Environmental Enrichment

The administration of haloperidol (HAL) once-daily for 19 days after experimental traumatic brain injury (TBI) impedes recovery and attenuates the efficacy of environmental enrichment (EE). However, it is unknown how intermittent administration of HAL affects the recovery process when paired with EE. Addressing the uncertainty is relevant because daily HAL is not always warranted to manage TBI-induced agitation in the clinic, and indeed intermittent therapy may be a more common approach. Hence, the aim of the study was to test the hypothesis that intermittent HAL would neither impair recovery in standard (STD)-housed controls nor attenuate the efficacy of EE. Anesthetized adult male rats received a cortical impact or sham injury and then were housed in STD or EE conditions. Beginning 24 h later, HAL (0.5 mg/kg; intraperitoneally [i.p.]) was administered either once-daily for 19 days or once every other day, whereas vehicle (VEH; 1 mL/kg; i.p.) was administered once daily. Motor performance and cognition were assessed on post-injury days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. SHAM controls performed better than all TBI groups on motor and spatial learning [p < 0.05], but did not differ from the TBI + EE + daily VEH group on memory retention [p > 0.05]. The TBI + EE + daily VEH and TBI + EE + intermittent HAL groups did not differ from one another on beam-walk or spatial learning [p > 0.05], and both performed better than all other TBI groups [p < 0.05]. In contrast, the TBI + STD + daily HAL group performed worse than all TBI groups on spatial learning [p < 0.05]. No difference in any endpoint was revealed between the TBI + STD + intermittent HAL and TBI + STD + daily VEH groups [p > 0.05]. The results support the hypothesis that HAL is not detrimental when provided intermittently. If translatable to the clinic, intermittent HAL may be used to control TBI-induced agitation without negatively affecting spontaneous recovery or rehabilitative efficacy.

Psychopharmacology of traumatic brain injury

The pathophysiology of traumatic brain injury (TBI) can be highly variable, involving functional and/or structural damage to multiple neuroanatomical networks and neurotransmitter systems. This wide-ranging potential for physiologic injury is reflected in the diversity of neurobehavioral and neurocognitive symptoms following TBI. Here, we aim to provide a succinct, clinically relevant, up-to-date review on psychopharmacology for the most common sequelae of TBI in the postacute to chronic period. Specifically, treatment for neurobehavioral symptoms (depression, mania, anxiety, agitation/irritability, psychosis, pseudobulbar affect, and apathy) and neurocognitive symptoms (processing speed, attention, memory, executive dysfunction) will be discussed. Treatment recommendations will reflect general clinical practice patterns and the research literature.

Dose-dependent neurorestorative effects of amantadine after cortical impact injury

Numerous pharmacotherapies have been evaluated after experimental traumatic brain injury (TBI). While amantadine (AMT) has shown potential for clinical efficacy, the few studies on its effectiveness have been mixed. It is possible that suboptimal dosing, due to the evaluation of only one dose, may be causing the discrepancies in outcomes. Hence, the goal of the current study was to conduct a dose response of AMT after TBI to determine an optimal behavioral benefit. Anesthetized adult male rats received either a cortical impact of moderate severity or sham injury and then were randomly assigned to receive once daily intraperitoneally injections of AMT (10, 20, or 40 mg/kg) or saline vehicle (VEH, 1 mL/kg) commencing 24 h after injury for 19 days. Motor and cognitive function were assessed on post-operative days 1-5 and 14-19, respectively. There were no statistical differences among the sham groups treated with AMT or VEH so the data were pooled. AMT (20 mg/kg) facilitated beam-balance recovery and spatial learning relative to VEH-treated controls (p < 0.05). No other doses of AMT were effective. These results indicate that dosing should be carefully considered when assessing the effects of pharmacotherapies after TBI so that potential benefits are not inadvertently missed.

Towards Targeted Brain Stimulation in Stroke: Connectivity as a Biomarker of Response

Stroke is a leading cause of adult disability. New treatments capable of assisting recovery hold significant potential to improve quality of life for many stroke survivors. Transcranial direct current stimulation is one technique that has received much attention due to its potential to promote neuroplasticity and enhance recovery. However, current evidence suggests this is not a one-size-fits-all treatment with indication that responses are highly variable. Using electroencephalography, Hordacre et al recently demonstrated that connectivity between the ipsilesional motor cortex, ipsilesional parietal cortex, and contralesional frontotemporal cortex was a strong predictor of the neurophysiological response to anodal transcranial direct current stimulation applied to the ipsilesional motor cortex in people with chronic ischemic stroke. Based on this outcome, we discuss the potential for connectivity to be used as a biomarker to target transcranial direct current stimulation. This includes identification of a connectivity threshold which could be used to select stroke survivors who are likely to respond to this potentially beneficial neuromodulatory treatment. Furthermore, we discuss treatment approaches for those identified as unlikely to benefit from ipsilesional anodal transcranial direct current stimulation based on connectivity profile. This represents an important progression towards targeting transcranial direct current stimulation for best treatment outcome based on individual connectivity characteristics.

Long-term deficits in risky decision-making after traumatic brain injury on a rat analog of the Iowa gambling task

Traumatic brain injury (TBI) affects 2.8 million people annually in the United States, with significant populations suffering from ongoing cognitive dysfunction. Impairments in decision-making can have major implications for patients and their caregivers, often enduring for years to decades, yet are rarely explored in experimental TBI. In the current study, the Rodent Gambling Task (RGT), an Iowa Gambling Task analog, was used to assess risk-based decision-making and motor impulsivity after TBI. During testing, rats chose between options associated with different probabilities of reinforcement (sucrose) or punishment (timeout). To determine effects of TBI on learned behaviors versus the learning process, rats were trained either before, or after, a bilateral frontal controlled cortical impact TBI, and then assessed for 12 weeks. To evaluate the degree to which monoamine systems, such as dopamine, were affected by TBI, rats were given an amphetamine challenge, and behavior recorded. Injury immediately and chronically decreased optimal decision-making, and biased rats towards both riskier, and safer (but suboptimal) choices, regardless of prior learning history. TBI also increased motor impulsivity across time, reflecting ongoing neural changes. Despite these similarities in trained and acquisition rats, those that learned the task after injury demonstrated reduced effects of amphetamine on optimal decision-making, suggesting a lesser role of monoamines in post-injury learning. Amphetamine also dose-dependently reduced motor impulsivity in injured rats. This study opens up the investigation of psychiatric-like dysfunction in animal models of TBI and tasks such as the RGT will be useful in identifying therapeutics for the chronic post-injury period.

Post-stroke neovascularization and functional outcomes differ in diabetes depending on severity of injury and sex: Potential link to hemorrhagic transformation

Diabetes is associated with increased risk and worsened outcome of stroke. Previous studies showed that male diabetic animals had greater hemorrhagic transformation (HT), profound loss of cerebral vasculature, and poor behavioral outcomes after ischemic stroke induced by suture or embolic middle cerebral artery occlusion (MCAO). Females are protected from stroke until reaching the menopause age, but young females with diabetes have a higher risk of stroke and women account for the majority of stroke mortality. The current study postulated that diabetes is associated with greater vascular injury and exacerbated sensorimotor and cognitive outcome after stroke even in young female animals. Male and female control and diabetic animals were subjected to transient MCAO and followed for 3 or 14 days to assess the neurovascular injury and repair. The vascularization indices after stroke were lower in male diabetic animals with 90-min but not 60-min ischemia/reperfusion injury, while there was no change in female groups. Cognitive deficits were exacerbated in both male and female groups regardless of the injury period, while the sensorimotor dysfunction was worsened in male diabetic animals with longer ischemia time. These results suggest that diabetes negates the protection afforded by sex in young female animals, and post-stroke vascularization pattern is influenced by the degree of injury and correlates with functional outcome in both sexes. Vasculoprotection after acute ischemic stroke may provide a novel therapeutic strategy in diabetes.

Efficacy and Harms of Pharmacological Interventions for Neurobehavioral Symptoms in Post-Traumatic Amnesia after Traumatic Brain Injury: A Systematic Review

Many individuals in post-traumatic amnesia (PTA) following traumatic brain injury (TBI) experience neurobehavioral symptoms (NBS) in addition to disorientation and amnesia. These symptoms are associated with low rehabilitation engagement, self-inflicted harm, and risk of violence. The aim of this systematic review was to evaluate the efficacy and harms of pharmacological interventions for NBS in PTA following TBI in adults. Studies in English published before December 2017 were reviewed. Six databases were searched, with additional hand searching of key journals, clinical trials registries, and international drug regulators. Evidence quality was assessed using Joanna Briggs Institute Critical Appraisal Instruments. Thirteen studies were identified: three randomized controlled trials (RCTs), three cohort studies, and seven case series. In the RCTs, neither amantadine nor sertraline reduced NBS. Less rigorous studies reported reduced NBS in patients administered haloperidol, ziprasidone, carbamazepine, amitriptyline, desipramine, and varied neuroleptics. There is a paucity of well-designed, adequately powered and controlled studies of pharmacological interventions for NBS in PTA. More research is needed to provide evidence-based treatment recommendations and improve care.

Unravelling motor behaviour hallmarks in intoxicated adolescents: methylmercury subtoxic-dose exposure and binge ethanol intake paradigm in rats

Methylmercury (MeHg) is a hazardous environmental pollutant, affecting Amazon basin communities by anthropogenic activities. The exact safe level of MeHg exposure is unclear, despite the efforts of health international societies to avoid mercury (Hg) poisoning. Central nervous system is severely impacted by Hg intoxication, reflecting on motor impairment. In addition, alcohol has been associated to an overall brain damage. According to lifestyle of Amazon riverside communities, alcohol intake occurs frequently. Thus, we investigated if continuous MeHg exposure at low doses during adolescence displays motor deficits (experiment 1). In the experiment 2, we examine if the co-intoxication (i.e. MeHg plus ethanol exposure) during adolescence intensify motor damage. In the experiment 1, Wistar adolescent rats (31 days old) received chronic exposure to low dose (CELD) of MeHg (40 μg/kg/day) for 35 days. For the experiment 2, five sessions of alcohol binge drinking paradigm (3ON-4OFF; 3.0 g/kg/day) were employed associated to MeHg intoxication. Motor behaviour was evaluated by the open field, pole test, beam walking and rotarod paradigms. CELDS of MeHg display motor function damage, related to hypoactivity, bradykinesia-like behaviour, coordination deficits and motor learning impairment. Co-intoxication of MeHg plus ethanol reduced cerebellar Hg content, however also resulted in motor behavioural impairment, as well as additive effects on bradykinesia and fine motor evaluation.

The Intersection of Central Dopamine System and Stroke: Potential Avenues Aiming at Enhancement of Motor Recovery

Dopamine, a major neurotransmitter, plays a role in a wide range of brain sensorimotor functions. Parkinson's disease and schizophrenia are two major human neuropsychiatric disorders typically associated with dysfunctional dopamine activity levels, which can be alleviated through the druggability of the dopaminergic systems. Meanwhile, several studies suggest that optimal brain dopamine activity levels are also significantly impacted in other serious neurological conditions, notably stroke, but this has yet to be fully appreciated at both basic and clinical research levels. This is of utmost importance as there is a need for better treatments to improve recovery from stroke. Here, we discuss the state of knowledge regarding the modulation of dopaminergic systems following stroke, and the use of dopamine boosting therapies in animal stroke models to improve stroke recovery. Indeed, studies in animals and humans show stroke leads to changes in dopamine functioning. Moreover, evidence from animal stroke models suggests stimulation of dopamine receptors may be a promising therapeutic approach for enhancing motor recovery from stroke. With respect to the latter, we discuss the evidence for several possible receptor-linked mechanisms by which improved motor recovery may be mediated. One avenue of particular promise is the subtype-selective stimulation of dopamine receptors in conjunction with physical therapy. However, results from clinical trials so far have been more mixed due to a number of potential reasons including, targeting of the wrong patient populations and use of drugs which modulate a wide array of receptors. Notwithstanding these issues, it is hoped that future research endeavors will assist in the development of more refined dopaminergic therapeutic approaches to enhance stroke recovery.

Spontaneous recovery after controlled cortical impact injury is not impeded by intermittent administration of the antipsychotic drug risperidone

Several preclinical studies have reported that daily administration of the antipsychotic drug (APD) risperidone (RISP) impedes recovery after traumatic brain injury (TBI). However, it is not known whether intermittent dosing would produce similar deleterious effects. The relevance of providing APDs intermittently is that not all patients in rehabilitation require daily treatments to manage TBI-induced agitation. Hence, the goal of the current study was to test the hypothesis that intermittent (vs. daily) administration of RISP would be less disturbing to motor and cognitive recovery after TBI. Anesthetized adult male rats were subjected to either a cortical impact of moderate severity or sham injury and then were randomly assigned to groups receiving intraperitoneal injections of vehicle (VEH; 1.0 mL/kg) or RISP (0.45 mg/kg) 1x, 3x, or 7x per week until the completion of behavioral testing, which consisted of motor and cognitive assessments on post-operative days 1-5 and 14-19, respectively. The group receiving RISP 7x week exhibited greater motor and cognitive impairment compared to those receiving RISP 1x or 3x per week, or VEH [p<0.05]. Moreover, no differences were observed between the intermittent RISP groups vs. VEH [p>0.05], which supports the hypothesis. A potential clinical ramification is that RISP may be safe to manage agitation after TBI, but only when used sparingly.

Clostridium butyricum exerts a neuroprotective effect in a mouse model of traumatic brain injury via the gut-brain axis

BACKGROUND

Traumatic brain injury (TBI) is a common occurrence following gastrointestinal dysfunction. Recently, more and more attentions are being focused on gut microbiota in brain and behavior. Glucagon-like peptide-1 (GLP-1) is considered as a mediator that links the gut-brain axis. The aim of this study was to explore the neuroprotective effects of Clostridium butyricum (Cb) on brain damage in a mouse model of TBI.

METHODS

Male C57BL/6 mice were subjected to a model of TBI-induced by weight-drop impact head injury and were treated intragastrically with Cb. The cognitive deficits, brain water content, neuronal death, and blood-brain barrier (BBB) permeability were evaluated. The expression of tight junction (TJ) proteins, Bcl-2, Bax, GLP-1 receptor (GLP-1R), and phosphorylation of Akt (p-Akt) in the brain were also measured. Moreover, the intestinal barrier permeability, the expression of TJ protein and GLP-1, and IL-6 level in the intestine were detected.

RESULTS

Cb treatment significantly improved neurological dysfunction, brain edema, neurodegeneration, and BBB impairment. Meanwhile, Cb treatment also significantly increased the expression of TJ proteins (occludin and zonula occluden-1), p-Akt and Bcl-2, but decreased expression of Bax. Moreover, Cb treatment exhibited more prominent effects on decreasing the levels of plasma d-lactate and colonic IL-6, upregulating expression of Occludin, and protecting intestinal barrier integrity. Furthermore, Cb-treated mice showed increased the secretion of intestinal GLP-1 and upregulated expression of cerebral GLP-1R.

CONCLUSIONS

Our findings demonstrated the neuroprotective effect of Cb in TBI mice and the involved mechanisms were partially attributed to the elevating GLP-1 secretion through the gut-brain axis.

Protective Effects of Notoginsenoside R1 via Regulation of the PI3K-Akt-mTOR/JNK Pathway in Neonatal Cerebral Hypoxic-Ischemic Brain Injury

Notoginsenoside R1 (NGR1) is a predominant phytoestrogen extracted from Panax notoginseng that has recently been reported to play important roles in the treatment of cardiac dysfunction, diabetic kidney disease, and acute liver failure. Studies have suggested that NGR1 may be a viable treatment of hypoxic-ischemic brain damage (HIBD) in neonates by reducing endoplasmic reticulum stress via estrogen receptors (ERs). However, whether NGR1 has other neuroprotective mechanisms or long-term neuroprotective effects is unclear. In this study, oxygen-glucose deprivation/reoxygenation (OGD/R) in primary cortical neurons and unilateral ligation of the common carotid artery (CCL) in 7-day-old postnatal Sprague Dawley (SD) rats followed by exposure to a hypoxic environment were used to mimic an HIBD episode. We assessed the efficacy of NGR1 by measuring neuronal damage with MTT assay and assessed brain injury by TTC staining and brain water content detection 24–48 h after OGD/HIE. Simultaneously, we measured the long-term neurophysiological effects using the beam walking test (5 weeks after HI) and Morris water maze test 5–6 weeks after HI. Expression of PI3K-Akt-mTOR/JNK (24 h after HI or OGD/R) proteins was detected by Western blotting after stimulation with HI, NGR1, LY294002 (PI3K inhibitor), 740Y-P (PI3K agonist), or ICI 182780(estrogen receptors inhibitor). The results indicated that NGR1 exerted neuroprotective effects by inhibiting neuronal apoptosis and promoting cell survival via the PI3K-Akt-mTOR/JNK signaling pathways by targeting ER in neonatal hypoxic–ischemic injury.

TOPK Promotes Microglia/Macrophage Polarization towards M2 Phenotype via Inhibition of HDAC1 and HDAC2 Activity after Transient Cerebral Ischemia

T-LAK-cell-originated protein kinase (TOPK) is a newly identified member of the mitogen-activated protein kinase family. Our previous study has showed that TOPK has neuroprotective effects against cerebral ischemia-reperfusion injury. Here, we investigated the involvement of TOPK in microglia/ macrophage M1/M2 polarization and the underlying epigenetic mechanism. The expression profiles, co-localization and in vivo interaction of TOPK, M1/M2 surface markers, and HDAC1/HDAC2 were detected after middle cerebral artery occlusion models (MCAO). We demonstrated that TOPK, the M2 surface markers CD206 and Arg1, p-HDAC1, and p-HDAC2 showed a similar pattern of in vivo expression over time after MCAO. TOPK co-localized with CD206, p-HDAC1, and p-HDAC2 positive cells, and was shown to bind to HDAC1 and HDAC2. In vitro study showed that TOPK overexpression in BV2 cells up-regulated CD206 and Arg1, and promoted the phosphorylation of HDAC1 and HDAC2. In addition, TOPK overexpression also prevented LPS plus IFN-γ-induced M1 transformation through reducing release of inflammatory factor of M1 phenotype TNF-α, IL-6 and IL-1β, and increasing TGF-β release and the mRNA levels of TGF-β and SOCS3, cytokine of M2 phenotype and its regulator. Moreover, the increased TNF-α induced by TOPK siRNA could be reversed by HDAC1/HDAC2 inhibitor, FK228. TOPK overexpression increased M2 marker expression in vivo concomitant with the amelioration of cerebral injury, neurological functions deficits, whereas TOPK silencing had the opposite effects, which were completely reversed by the FK228 and partially by the SAHA. These findings suggest that TOPK positively regulates microglia/macrophage M2 polarization by inhibiting HDAC1/HDAC2 activity, which may contribute to its neuroprotective effects against cerebral ischemia-reperfusion injury.

Pharmacological Stimulation of Neuronal Plasticity in Acquired Brain Injury

INTRODUCTION

Brain injuries are one of the leading causes of disability worldwide. It is estimated that nearly half of patients who develop severe sequelae will continue with a chronic severe disability despite having received an appropriate rehabilitation program. For more than 3 decades, there has been a worldwide effort to investigate the possibility of pharmacologically stimulating the neuroplasticity process for enhancing the recovery of these patients.

OBJECTIVE

The objective of this article is to make a critical and updated review of the available evidence that supports the positive effect of different drugs on the recovery from brain injury.

METHOD

To date, there have been several clinical trials that tested different drugs that act on different neurotransmitter systems: catecholaminergic, cholinergic, serotonergic, and glutamatergic. There is both basic and clinical evidence that may support some positive effect of these drugs on motor, cognitive, and language skills; however, only few of the available studies are of sufficient methodological quality (placebo controlled, randomized, blinded, multicenter, etc) to make solid conclusions about their beneficial effects.

CONCLUSIONS

Currently, the pharmacological stimulation of neuroplasticity still does not have enough scientific evidence to make a systematic therapeutic recommendation for all patients, but it certainly is a feasible and very promising field for future research.

Environmental enrichment, alone or in combination with various pharmacotherapies, confers marked benefits after traumatic brain injury

Traumatic brain injury (TBI) is a significant health care issue that affects over ten million people worldwide. Treatment options are limited with numerous failures resulting from single therapies. Fortunately, several preclinical studies have shown that combination treatment strategies may afford greater improvement and perhaps can lead to successful clinical translation, particularly if one of the therapies is neurorehabilitation. The aim of this review is to highlight TBI studies that combined environmental enrichment (EE), a preclinical model of neurorehabilitation, with pharmacotherapies. A series of PubMed search strategies yielded only nine papers that fit the criteria. The consensus is that EE provides robust neurobehavioral, cognitive, and histological improvement after experimental TBI and that the combination of EE with some pharmacotherapies can lead to benefits beyond those revealed by single therapies. However, it is noted that EE can be challenged by drugs such as the acetylcholinesterase inhibitor, donepezil, and the antipsychotic drug, haloperidol, which attenuate its efficacy. These findings may help shape clinical neurorehabilitation strategies to more effectively improve patient outcome. Potential mechanisms for the EE and pharmacotherapy-induced effects are also discussed. This article is part of the Special Issue entitled "Neurobiology of Environmental Enrichment".

Neuroprotective effects of pifithrin-α against traumatic brain injury in the striatum through suppression of neuroinflammation, oxidative stress, autophagy, and apoptosis

Cortical and hippocampal neuronal damages caused by traumatic brain injury (TBI) are associated with motor and cognitive impairments; however, only little attention paid to the striatal damage. It is known that the p53 tumor-suppressor transcription factor participated in TBI-induced secondary brain damage. We investigated how the p53 inactivator pifithrin (PFT)-α affected TBI-induced striatal neuronal damage at 24 h post-injury. Sprague-Dawley rats subjected to a controlled cortical impact were used as TBI models. We observed that p53 mRNA significantly increased, whereas p53 protein expression was distributed predominantly in neurons but not in glia cells in striatum after TBI. PFT-α improved motor deficit following TBI. PFT-α suppressed TBI-induced striatal glial activation and expression of proinflammatory cytokines. PFT-α alleviated TBI-induced oxidative damage TBI induced autophagy was evidenced by increased protein expression of Beclin-1 and shift of microtubule-associated light chain (LC)3-I to LC3-II, and decreased p62. These effects were reduced by PFT-α. Post-injury PFT-α treatment reduced the number of degenerating (FJC-positive) and apoptotic neurons. Our results suggest that PFT-α may provide neuroprotective effects via p53-dependent or -independent mechanisms depending on the cell type and timing after the TBI and can possibly be developed into a novel therapy to ameliorate TBI-induced neuronal damage.

Elucidating opportunities and pitfalls in the treatment of experimental traumatic brain injury to optimize and facilitate clinical translation

The aim of this review is to discuss the research presented in a symposium entitled "Current progress in characterizing therapeutic strategies and challenges in experimental CNS injury" which was presented at the 2016 International Behavioral Neuroscience Society annual meeting. Herein we discuss diffuse and focal traumatic brain injury (TBI) and ensuing chronic behavioral deficits as well as potential rehabilitative approaches. We also discuss the effects of stress on executive function after TBI as well as the response of the endocrine system and regulatory feedback mechanisms. The role of the endocannabinoids after CNS injury is also discussed. Finally, we conclude with a discussion of antipsychotic and antiepileptic drugs, which are provided to control TBI-induced agitation and seizures, respectively. The review consists predominantly of published data.

Neuroprotective Effect of Sirt2-specific Inhibitor AK-7 Against Acute Cerebral Ischemia is P38 Activation-dependent in Mice

Cerebral ischemia is the most common cause of stroke with high morbidity, disability and mortality. Sirtuin-2 (Sirt2), a vitally important NAD⁺-dependent deacetylase which has been widely researched in central nervous system diseases, has also been identified as a promising treatment target using its specific inhibitors such as AK-7. In this study, we found that P38 was specifically activated after focal cerebral ischemic injury, and it was also significantly activated after AK-7 administration in a concentration-dependent manner in vitro and in vivo. AK-7 decreased the infarction volume remarkably and promoted the recovery of neurological function efficiently in the mice evaluated by behavior tests. In contrast, pP38 inhibition increased the infarct volume and exacerbated the symptoms of paralysis. Herein, we suggest AK-7 improves the outcome of brain ischemia in dependence on the P38 activation in mice, which may serve as a strategy for the treatment of stroke.

Detecting Behavioral Deficits in Rats After Traumatic Brain Injury

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, few studies have investigated the long-term effects of injury in rodent models of TBI. Shown here are behavioral measures that are well-established in TBI research for times early after injury, such as two weeks, until two months. Some of these methods have previously been used at later times after injury, up to one year, but by very few laboratories. The methods demonstrated here are a short neurological assessment to test reflexes, a Beam-Balance to test balance, a Beam-Walk to test balance and motor coordination, and a working memory version of the Morris water maze that can be sensitive to deficits in reference memory. Male rats were handled and pre-trained to neurological, balance, and motor coordination tests prior to receiving parasagittal fluid percussion injury (FPI) or sham injury. Rats can be tested on the short neurological assessment (neuroscore), the beam-balance, and the Beam-Walk multiple times, while testing on the water maze can only be done once. This difference is because rats can remember the task, thus confounding the results if repeated testing is attempted in the same animal. When testing from one to three days after injury, significant differences are detected in all three non-cognitive tasks. However, differences in the Beam-Walk task were not detectable at later time points (after 3 months). Deficits were detected at 3 months in the Beam-Balance and at 6 months in the neuroscore. Deficits in working memory were detected out to 12 months after injury, and a deficit in a reference memory first appeared at 12 months. Thus, standard behavioral tests can be useful measures of persistent behavioral deficits after FPI.

Effects of Mild Blast Traumatic Brain Injury on Cerebral Vascular, Histopathological, and Behavioral Outcomes in Rats

To determine the effects of mild blast-induced traumatic brain injury (bTBI), several groups of rats were subjected to blast injury or sham injury in a compressed air-driven shock tube. The effects of bTBI on relative cerebral perfusion (laser Doppler flowmetry [LDF]), and mean arterial blood pressure (MAP) cerebral vascular resistance were measured for 2 h post-bTBI. Dilator responses to reduced intravascular pressure were measured in isolated middle cerebral arterial (MCA) segments, ex vivo, 30 and 60 min post-bTBI. Neuronal injury was assessed (Fluoro-Jade C [FJC]) 24 and 48 h post-bTBI. Neurological outcomes (beam balance and walking tests) and working memory (Morris water maze [MWM]) were assessed 2 weeks post-bTBI. Because impact TBI (i.e., non-blast TBI) is often associated with reduced cerebral perfusion and impaired cerebrovascular function in part because of the generation of reactive oxygen and nitrogen species such as peroxynitrite (ONOO-), the effects of the administration of the ONOO- scavenger, penicillamine methyl ester (PenME), on cerebral perfusion and cerebral vascular resistance were measured for 2 h post-bTBI. Mild bTBI resulted in reduced relative cerebral perfusion and MCA dilator responses to reduced intravascular pressure, increases in cerebral vascular resistance and in the numbers of FJC-positive cells in the brain, and significantly impaired working memory. PenME administration resulted in significant reductions in cerebral vascular resistance and a trend toward increased cerebral perfusion, suggesting that ONOO- may contribute to blast-induced cerebral vascular dysfunction.

Psychiatric sequelae of acquired brain injury

Improvements over recent decades in acute care of the brain-injured now ensure that all but the most severely injured survive. The legacy of that survival is an increasing number of people with enduring organic mental disorders. Here, I will focus upon the psychiatric sequelae of five types of severe single-insult brain injury: head trauma, subarachnoid haemorrhage, and hypoxic, hypoglycaemic and postencephalitic injury. Thrombotic stroke is a common and important cause of brain injury but the psychiatric consequences have been more extensively studied and are fairly well-known (Robinson & Price, 1982; Starkstein et al, 1987). Damage due to alcohol and associated malnutrition is also well-documented (Jacobson & Lishman, 1987, 1990). Neither will be specifically addressed here, though some of the consequences of brain injury are similar, regardless of cause.

Treatments to Promote Neural Repair after Stroke

Stroke remains a major cause of human disability worldwide. In parallel with advances in acute stroke interventions, new therapies are under development that target restorative processes. Such therapies have a treatment time window measured in days, weeks, or longer and so have the advantage that they may be accessible by a majority of patients. Several categories of restorative therapy have been studied and are reviewed herein, including drugs, growth factors, monoclonal antibodies, activity-related therapies including telerehabilitation, and a host of devices such as those related to brain stimulation or robotics. Many patients with stroke do not receive acute stroke therapies or receive them and do not derive benefit, often surviving for years thereafter. Therapies based on neural repair hold the promise of providing additional treatment options to a majority of patients with stroke.

Albeit nocturnal, rats subjected to traumatic brain injury do not differ in neurobehavioral performance whether tested during the day or night

Behavioral assessments in rats are overwhelmingly conducted during the day, albeit that is when they are least active. This incongruity may preclude optimal performance. Hence, the goal of this study was to determine if differences in neurobehavior exist in traumatic brain injured (TBI) rats when assessed during the day vs. night. The hypothesis was that the night group would perform better than the day group on all behavioral tasks. Anesthetized adult male rats received either a cortical impact or sham injury and then were randomly assigned to either Day (1:00-3:00p.m.) or Night (7:30-9:30p.m.) testing. Motor function (beam-balance/walk) was conducted on post-operative days 1-5 and cognitive performance (spatial learning) was assessed on days 14-18. Corticosterone (CORT) levels were quantified at 24h and 21days after TBI. No significant differences were revealed between the TBI rats tested during the Day vs. Night for motor or cognition (p's<0.05). CORT levels were higher in the Night-tested TBI and sham groups at 24h (p<0.05), but returned to baseline and were no longer different by day 21 (p>0.05), suggesting an initial, but transient, stress response that did not affect neurobehavioral outcome. These data suggest that the time rats are tested has no noticeable impact on their performance, which does not support the hypothesis. The finding validates the interpretations from numerous studies conducted when rats were tested during the day vs. their natural active period.

Spontaneous recovery of traumatic brain injury-induced functional deficits is not hindered by daily administration of lorazepam

Agitation and aggression are common sequelae of traumatic brain injury (TBI) and pose a challenge to physicians and other health providers during acute patient care and subsequent neurorehabilitation. Antipsychotic drugs (APDs) are routinely administered to manage TBI patients displaying such maladaptive behaviors despite several clinical and preclinical studies demonstrating that they hinder recovery. A potentially viable alternative to APDs may be the benzodiazepines, which have differing mechanisms of action. Hence, the aim of the study was to test the hypothesis that lorazepam (LOR) would not impede recovery after TBI. Anesthetized adult male rats received a cortical impact or sham injury and then were intraperitoneally administered LOR (0.1mg/kg, 1.0mg/kg, or 2.0mg/kg) or vehicle (VEH; 1mL/kg) commencing 24-h after surgery and once daily for 19days. Motor and cognitive outcomes were assessed on post-operative days 1-5 and 14-19, respectively. No differences were revealed among the four sham control groups and thus they were pooled into one inclusive SHAM group. The SHAMs performed better than all TBI groups on all assessments (p<0.05). Regarding TBI, the 2.0mg/kg LOR group performed better than the VEH and 0.1mg/kg or 1.0mg/kg LOR groups on every task (p<0.05); no differences were observed among the latter three groups on any endpoint (p>0.05). Overall, these preclinical behavioral data support the hypothesis and reveal a therapeutic benefit with the higher dose of LOR. The findings suggest that LOR may be an alternative, to APDs, for controlling agitation without compromising spontaneous recovery and perhaps could afford a dual benefit by also promoting therapeutic efficacy.

Efficacy and harms of pharmacological interventions for neurobehavioral symptoms in post traumatic amnesia after traumatic brain injury: a systematic review and meta-analysis protocol

REVIEW OBJECTIVE/QUESTION

The objective of this systematic review is to synthesize the best available evidence on the effectiveness and harms of pharmacotherapy as compared to all types of comparators for the management of neurobehavioral symptoms in post-traumatic amnesia in adults aged 16 years and over who have sustained a traumatic brain injury. This review forms part of a larger project which aims to gather the evidence for the pharmacological treatment of neurobehavioral symptoms post traumatic brain injury as a prelude to the development of a clinical guideline.

2-Cl-MGV-1 Ameliorates Apoptosis in the Thalamus and Hippocampus and Cognitive Deficits After Cortical Infarct in Rats

BACKGROUND AND PURPOSE

Focal cortical infarction causes neuronal apoptosis in the ipsilateral nonischemic thalamus and hippocampus, which is potentially associated with poststroke cognitive deficits. TSPO (translocator protein) is critical in regulating mitochondrial apoptosis pathways. We examined the effects of the novel TSPO ligand 2-(2-chlorophenyl) quinazolin-4-yl dimethylcarbamate (2-Cl-MGV-1) on poststroke cognitive deficits, neuronal mitochondrial apoptosis, and secondary damage in the ipsilateral thalamus and hippocampus after cortical infarction.

METHODS

One hundred fourteen hypertensive rats underwent successful distal middle cerebral artery occlusion (n=76) or sham procedures (n=38). 2-Cl-MGV-1 or dimethyl sulfoxide as vehicle was administrated 2 hours after distal middle cerebral artery occlusion and then for 6 or 13 days (n=19 per group). Spatial learning and memory were tested using the Morris water maze. Secondary degeneration and mitochondrial apoptosis in the thalamus and hippocampus were assessed using Nissl staining, immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick end labeling, JC-1 staining, and immunoblotting 7 and 14 days after surgery.

RESULTS

Infarct volumes did not significantly differ between the vehicle and 2-Cl-MGV-1 groups. There were more neurons and fewer glia in the ipsilateral thalamus and hippocampus in the vehicle groups than in the sham-operated group 7 and 14 days post-distal middle cerebral artery occlusion. 2-Cl-MGV-1 significantly ameliorated spatial cognitive impairment and decreased neuronal death and glial activation when compared with vehicle treatment (P<0.05). The collapse of mitochondrial transmembrane potential and cytoplasmic release of apoptosis-inducing factors and cytochrome c was prevented within the thalamus. Caspase cleavage and the numbers of terminal deoxynucleotidyl transferase dUTP nick end labeling⁺ or Nissl atrophic cells were reduced within the thalamus and hippocampus. This was accompanied by upregulation of B-cell lymphoma 2 and downregulation of Bax (P<0.05).

CONCLUSIONS

2-Cl-MGV-1 reduces neuronal apoptosis via mitochondrial-dependent pathways and attenuates secondary damage in the nonischemic thalamus and hippocampus, potentially contributing to ameliorated cognitive deficits after cortical infarction.

Rehabilitative Success After Brain Trauma by Augmenting a Subtherapeutic Dose of Environmental Enrichment With Galantamine

BACKGROUND

Environmental enrichment (EE) confers benefits after traumatic brain injury (TBI) when provided daily for > 6 hours, but not 2 or 4 hours, which more accurately reflects the daily amount of clinical rehabilitation. The lack of benefit with sub-therapeutic EE suggests that augmentation with galantamine (GAL), which enhances cognition after TBI, may be indicated to confer benefits.

OBJECTIVE

To test the hypothesis that 2 and 4 hours of EE paired with GAL will provide benefits comparable to 24 hours of EE alone. Moreover, all EE groups will perform better than the standard (STD)-housed GAL group.

METHODS

Anesthetized rats received a TBI or sham injury and then were randomized to receive intraperitoneal injections of GAL (2 mg/kg) or saline vehicle (VEH; 1 mL/kg) beginning 24 hours after surgery and once daily while receiving EE for 2, 4, or 24 hours. Motor and cognitive assessments were conducted on postoperative days 1-5 and 14-19, respectively.

RESULTS

Motor function was significantly improved in the TBI + 24-hour EE group versus the TBI + STD + VEH and TBI + STD + GAL groups ( P < .05). Cognitive performance was enhanced in all EE groups as well as in the TBI + STD + GAL versus TBI + STD + VEH ( P < .05). Moreover, the 2- and 4-hour EE groups receiving GAL did not differ from the 24-hour EE group ( P > .05) and performed better than GAL alone ( P < .05).

CONCLUSIONS

The findings support the hypothesis and have clinical relevance because, often, only brief rehabilitation may be available in the clinic and, thus, augmenting with a pharmacotherapy such as GAL may lead to outcomes that are significantly better than either therapy alone.

Stimulation of the mesencephalic locomotor region for gait recovery after stroke

OBJECTIVE

One-third of all stroke survivors are unable to walk, even after intensive physiotherapy. Thus, other concepts to restore walking are needed. Because electrical stimulation of the mesencephalic locomotor region (MLR) is known to elicit gait movements, this area might be a promising target for restorative neurostimulation in stroke patients with gait disability. The present study aims to delineate the effect of high-frequency stimulation of the MLR (MLR-HFS) on gait impairment in a rodent stroke model.

METHODS

Male Wistar rats underwent photothrombotic stroke of the right sensorimotor cortex and chronic implantation of a stimulating electrode into the right MLR. Gait was assessed using clinical scoring of the beam-walking test and video-kinematic analysis (CatWalk) at baseline and on days 3 and 4 after experimental stroke with and without MLR-HFS.

RESULTS

Kinematic analysis revealed significant changes in several dynamic and static gait parameters resulting in overall reduced gait velocity. All rats exhibited major coordination deficits during the beam-walking challenge and were unable to cross the beam. Simultaneous to the onset of MLR-HFS, a significantly higher walking speed and improvements in several dynamic gait parameters were detected by the CatWalk system. Rats regained the ability to cross the beam unassisted, showing a reduced number of paw slips and misses.

INTERPRETATION

MLR-HFS can improve disordered locomotor function in a rodent stroke model. It may act by shielding brainstem and spinal locomotor centers from abnormal cortical input after stroke, thus allowing for compensatory and independent action of these circuits. Ann Neurol 2017;82:828-840.

Combined Dextroamphetamine and Transcranial Direct Current Stimulation in Poststroke Aphasia

There is a growing need for various effective adjunctive treatment options for speech recovery after stroke. A pharmacological agent combined with noninvasive brain stimulation has not been previously reported for poststroke aphasia recovery. In this "proof of concept" study, we aimed to test the safety of a combined intervention consisting of dextroamphetamine, transcranial direct current stimulation, and speech and language therapy in subjects with nonfluent aphasia. Ten subjects with chronic nonfluent aphasia underwent two experiments where they received dextroamphetamine or placebo along with transcranial direct current stimulation and speech and language therapy on two separate days. The Western Aphasia Battery-Revised was used to monitor changes in speech performance. No serious adverse events were observed. There was no significant increase in blood pressure with amphetamine or deterioration in speech and language performance. Western Aphasia Battery-Revised aphasia quotient and language quotient showed a statistically significant increase in the active experiment. Comparison of proportional changes of aphasia quotient and language quotient in active experiment with those in placebo experiment showed significant difference. We showed that the triple combination therapy is safe and implementable and seems to induce positive changes in speech and language performance in the patients with chronic nonfluent aphasia due to stroke.

Noradrenergic antagonists mitigate amphetamine-induced recovery

Brain injury, including that due to stroke, leaves individuals with cognitive deficits that can disrupt daily aspect of living. As of now there are few treatments that shown limited amounts of success in improving functional outcome. The use of stimulants such as amphetamine have shown some success in improving outcome following brain injury. While the pharmacological mechanisms for amphetamine are known; the specific processes responsible for improving behavioral outcome following injury remain unknown. Understanding these mechanisms can help to refine the use of amphetamine as a potential treatment or lead to the use of other methods that share the same pharmacological properties. One proposed mechanism is amphetamine's impact upon noradrenaline (NA). In the current, study noradrenergic antagonists were administered prior to amphetamine to pharmacologically block α- and β-adrenergic receptors. The results demonstrated that the blockade of these receptors disrupted amphetamines ability to induce recovery from hemispatial neglect using an established aspiration lesion model. This suggests that amphetamine's ability to ameliorate neglect deficits may be due in part to noradrenaline. These results further support the role of noradrenaline in functional recovery. Finally, the development of polytherapies and combined therapeutics, while promising, may need to consider the possibility that drug interactions can negate the effectiveness of treatment.

An update on medications and noninvasive brain stimulation to augment language rehabilitation in post-stroke aphasia

INTRODUCTION

Aphasia is among the most debilitating outcomes of stroke. Aphasia is a language disorder occurring in 10-30% of stroke survivors. Speech and Language Therapy (SLT) is the gold standard, mainstay treatment for aphasia, but gains from SLT may be incomplete. Pharmaceutical and noninvasive brain stimulation (NIBS) techniques may augment the effectiveness of SLT. Areas covered: Herein reviewed are studies of the safety and efficacy of these adjunctive interventions for aphasia, including randomized placebo-controlled and open-label trials, as well as case series from Pubmed, using search terms 'pharmacological,' 'tDCS' or 'TMS' combined with 'aphasia' and 'stroke.' Expert commentary: Relatively small studies have included participants with a range of aphasia types and severities, using inconsistent interventions and outcome measures. Results to-date have provided promising, but weak to moderate evidence that medications and/or NIBS can augment the effects of SLT for improving language outcomes. We end with recommendations for future approaches to studying these interventions, with multicenter, double-blind, randomized controlled trials.