Established treatments for acute ischaemic stroke

Temporary Occlusion of Common Carotid Arteries Does Not Evoke Total Inhibition in the Activity of Corticospinal Tract Neurons in Experimental Conditions

Temporary occlusion of the common cervical artery is the reason for ischemic stroke in 25% of patients. Little data is provided on its effects, especially regarding neurophysiological studies verifying the neural efferent transmission within fibers of the corticospinal tract in experimental conditions. Studies were performed on 42 male Wistar rats. In 10 rats, ischemic stroke was evoked by permanent occlusion of the right carotid artery (group A); in 11 rats, by its permanent bilateral occlusion (B); in 10 rats, by unilateral occlusion and releasing after 5 min (C); and in 11 rats, by bilateral occlusion and releasing after 5 min (D). Efferent transmission of the corticospinal tract was verified by motor evoked potential (MEP) recordings from the sciatic nerve after transcranial magnetic stimulation. MEPs amplitude and latency parameters, oral measurements of temperature, and verification of ischemic effects in brain slides stained with hematoxylin and eosin staining (H + E) were analyzed. In all groups of animals, the results showed that five minutes of uni- or bilateral occlusion of the common carotid artery led to alterations in brain blood circulation and evoked changes in MEP amplitude (by 23.2% on average) and latency parameters (by 0.7 ms on average), reflecting the partial inability of tract fibers to transmit neural impulses. These abnormalities were associated with a significant drop in the body temperature by 1.5 °C on average. Ten minutes occlusion in animals from groups A and B resulted in an MEP amplitude decrease by 41.6%, latency increase by 0.9 ms, and temperature decrease by 2.9 °C of the initial value. In animals from groups C and D, five minutes of recovery of arterial blood flow evoked stabilization of the MEP amplitude by 23.4%, latency by 0.5 ms, and temperature by 0.8 °C of the initial value. In histological studies, the results showed that ischemia was most prominent bilaterally in sensory and motor areas, mainly for the forelimb, rather than the hindlimb, innervation of the cortex, putamen and caudate nuclei, globulus pallidus, and areas adjacent to the fornix of the third ventricle. We found that the MEP amplitude parameter is more sensitive than the latency and temperature variability in monitoring the ischemia effects course following common carotid artery infarction, although all parameters are correlated with each other. Temporary five-minute lasting occlusion of common carotid arteries does not evoke total and permanent inhibition in the activity of corticospinal tract neurons in experimental conditions. The symptoms of rat brain infarction are much more optimistic than those described in patients after stroke, and require further comparison with the clinical observations.

Phthalide derivative CD21 regulates the platelet- neutrophil extracellular trap-thrombin axis and protects against ischemic brain injury in rodents

Prothrombotic and proinflammatory properties of neutrophil extracellular traps (NETs) contribute to brain damage after ischemic stroke. CD21 is a novel phthalide neuroprotectant against cerebral ischemia in rodents. This study investigated effects of CD21 on the platelet-NET-thrombin axis and ischemic brain injury and the underlying mechanism. CD21 exerteddose-dependent neuroprotectionin rats that were subjected to2 h middle cerebral artery occlusion,dose-dependentlyinhibited adenosine diphosphate-mediatedplatelet aggregationin rats, and dose-dependentlyexertedanti-thrombotic activityin rodents that received a collagen-epinephrine combination, ferric chloride, or an arteriovenous shunt. Equimolar CD21 doses exerted stronger efficacy than 3-N-butylphthalide (NBP, natural phthalide for the treatment of ischemic stroke). CD21 dose-dependently improved regional cerebral blood flow, neurobehavioral deficits, and infarct volume in mice that were subjected to photothrombotic stroke (PTS). CD21 (13.79 mg/kg, i.v.) significantly decreased NET components (plasma dsDNA concentrations; mRNA levels of elastase, myeloperoxidase, and neutrophil gelatinase-associated lipocalin and protein level of citrullinated histone H3 in ischemic brain tissues), mRNA and protein levels of peptidyl-arginine deiminase 4 (PDA4, NET formation enzyme), and mRNA levels of NET-related inflammatory mediators (interleukin-1β, interleukin-17A, matrix metalloproteinase 8, and matrix metalloproteinase 9) in ischemic brain tissues, despite no effect on mRNA levels of deoxyribonuclease I (NET elimination enzyme). Pretreatment with compound C (inhibitor of adenosine monophosphate-activated protein kinase [AMPK]) significantly reversed the inhibitory effects of CD21 on NETs, PDA4, and inflammatory mediators in PTS mice. These results suggest that CD21 might regulate the platelet-NET-thrombin axis and protect against ischemic brain injury partly through the induction of AMPK activation.

Targeted Treatment of Ischemic Stroke by Bioactive Nanoparticle-Derived Reactive Oxygen Species Responsive and Inflammation-Resolving Nanotherapies

Stroke is a primary cause of death and disability worldwide, while effective and safe drugs remain to be developed for its clinical treatment. Herein, we report bioactive nanoparticle-derived multifunctional nanotherapies for ischemic stroke, which are engineered from a pharmacologically active oligosaccharide material (termed as TPCD) prepared by covalently conjugating a radical-scavenging compound (Tempol) and a hydrogen-peroxide-eliminating moiety of phenylboronic acid pinacol ester (PBAP) on β-cyclodextrin. Of note, combined functional moieties of Tempol and PBAP on β-cyclodextrin contribute to antioxidative and anti-inflammatory activities of TPCD. Cellularly, TPCD nanoparticles (i.e., TPCD NPs) reduced oxygen-glucose deprivation-induced overproduction of oxidative mediators, increased antioxidant enzyme expression, and suppressed microglial-mediated inflammation, thereby inhibiting neuronal apoptosis. After intravenous (i.v.) delivery, TPCD NPs could efficiently accumulate at the cerebral ischemic injury site of mice with middle cerebral artery occlusion (MCAO), showing considerable distribution in cells relevant to the pathogenesis of stroke. Therapeutically, TPCD NPs significantly decreased infarct volume and accelerated recovery of neurological function in MCAO mice. Mechanistically, efficacy of TPCD NPs is achieved by its antioxidative, anti-inflammatory, and antiapoptotic effects. Furthermore, TPCD NPs can function as a reactive oxygen species labile nanovehicle to efficiently load and triggerably release an inflammation-resolving peptide Ac2-26, giving rise to an inflammation-resolving nanotherapy (i.e., ATPCD NP). Compared to TPCD NP, ATPCD NP demonstrated notably enhanced in vivo efficacies, largely resulting from its additional inflammation-resolving activity. Consequently, TPCD NP-derived nanomedicines can be further developed as promising targeted therapies for stroke and other inflammation-associated cerebrovascular diseases.

Intravenous thrombolysis for acute ischemic stroke with extended time window

Background:

Intravenous thrombolysis (IVT) is an effective way for treating acute ischemic stroke (AIS). However, its effects have not been established among AIS patients with unclear stroke symptoms or with stroke onset for >4.5 h.

Methods:

We searched PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials and Google Scholar databases for randomized controlled trials that compared IVT (IVT group) and placebo or usual care (control group [CG]) in AIS patients with disease onset for >4.5 h. The outcomes of interest included the favorable functional outcome (defined as modified Rankin Scale [mRS] scores 0–1) at 90 days, the functional independence (defined as mRS scores 0–2) at 90 days, proportion of patients with symptomatic intracerebral hemorrhage (sICH) and death at 90 days. We assessed the risk of bias using the Cochrane tool. Pre-specified subgroup analyses were performed by age (≤70 years or >70 years), National Institute of Health Stroke Scale (NIHSS, ≤10 or >10) and time window (4.5–9.0 h or >9.0 h).

Results:

Four trials involving 848 patients were eligible. The risk of bias of included trials was low. Patients in the IVT group were more likely to achieve favorable functional outcomes (45.8% vs. 36.7%; OR 1.48, 95% CI 1.12–1.96) and functional independence (63.8% vs. 55.7%; OR 1.43, 95% CI 1.08–1.90) at 90 days, but had higher risk of sICH (3.0% vs. 0.5%; OR 5.28, 95% CI 1.35–20.68) at 90 days than those in the CG. No significant difference in death at 90 days was found between the two groups (7.0% vs. 4.1%; OR 1.80; 95% CI 0.97–3.34).

Conclusions:

Use of IVT in patients with extended time window may improve their functional outcomes at 90 days, although IVT may induce increased risk of sICH. Care of these patients should well balance the potential benefits and harms of IVT.

Cellular and Molecular Mechanisms of R/S-Roscovitine and CDKs Related Inhibition under Both Focal and Global Cerebral Ischemia: A Focus on Neurovascular Unit and Immune Cells

Ischemic stroke is the second leading cause of death worldwide. Following ischemic stroke, Neurovascular Unit (NVU) inflammation and peripheral leucocytes infiltration are major contributors to the extension of brain lesions. For a long time restricted to neurons, the 10 past years have shown the emergence of an increasing number of studies focusing on the role of Cyclin-Dependent Kinases (CDKs) on the other cells of NVU, as well as on the leucocytes. The most widely used CDKs inhibitor, (R)-roscovitine, and its (S) isomer both decreased brain lesions in models of global and focal cerebral ischemia. We previously showed that (S)-roscovitine acted, at least, by modulating NVU response to ischemia. Interestingly, roscovitine was shown to decrease leucocytes-mediated inflammation in several inflammatory models. Specific inhibition of roscovitine majors target CDK 1, 2, 5, 7, and 9 showed that these CDKs played key roles in inflammatory processes of NVU cells and leucocytes after brain lesions, including ischemic stroke. The data summarized here support the investigation of roscovitine as a potential therapeutic agent for the treatment of ischemic stroke, and provide an overview of CDK 1, 2, 5, 7, and 9 functions in brain cells and leucocytes during cerebral ischemia.

Migrainous Infarction and Cortical Spreading Depression

Migraine is a very common disorder of the nervous system. It shares similar physiological processes with stroke. Migrainous infarction is a rare complication of migraine with aura. The neuro-logical symptoms of migraine aura correspond to the cortical spreading depression and this depression can lead to a migrainous infarction. It is pertinent to state that the investigation and detection of the cortical depression might have a great clinical significance. Blood vessels in the cranium play an important role in the pathophysiology of migraine.  In the case of injured states of brain, the cortical spreading depression causes extreme vasoconstriction rather than vasodilation. The endothelial damage caused by the cortical spreading depression can result in hypercoagulability, leading to an increased risk of stroke. There are many genetic disorders in which migraine and stroke are the major symptoms and an insight into these disorders can help us in the understanding of complex mechanisms of migrainous infarction. It is pertinent to state that some derangements in the vascular function accompany migraine which may also serve as targets for research and treatment. This article will describe the hemodynamic and genetic relationship between migraine induced stroke and how it relates to the cortical spreading depression.

Protective Effects of a New C-Jun N-terminal Kinase Inhibitor in the Model of Global Cerebral Ischemia in Rats

c-Jun N-terminal kinase (JNK) is activated by various brain insults and is implicated in neuronal injury triggered by reperfusion-induced oxidative stress. Some JNK inhibitors demonstrated neuroprotective potential in various models, including cerebral ischemia/reperfusion injury. The objective of the present work was to study the neuroprotective activity of a new specific JNK inhibitor, IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt), in the model of global cerebral ischemia (GCI) in rats compared with citicoline (cytidine-5'-diphosphocholine), a drug approved for the treatment of acute ischemic stroke and to search for pleiotropic mechanisms of neuroprotective effects of IQ-1S. The experiments were performed in a rat model of ischemic stroke with three-vessel occlusion (model of 3VO) affecting the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. After 7-min episode of GCI in rats, 25% of animals died, whereas survived animals had severe neurological deficit at days 1, 3, and 5 after GCI. At day 5 after GCI, we observing massive loss of pyramidal neurons in the hippocampal CA1 area, increase in lipid peroxidation products in the brain tissue, and decrease in local cerebral blood flow (LCBF) in the parietal cortex. Moreover, blood hyperviscosity syndrome and endothelial dysfunction were found after GCI. Administration of IQ-1S (intragastrically at a dose 50 mg/kg daily for 5 days) was associated with neuroprotective effect comparable with the effect of citicoline (intraperitoneal at a dose of 500 mg/kg, daily for 5 days).The neuroprotective effect was accompanied by a decrease in the number of animals with severe neurological deficit, an increase in the number of animals with moderate degree of neurological deficit compared with control GCI group, and an increase in the number of unaltered neurons in the hippocampal CA1 area along with a significant decrease in the number of neurons with irreversible morphological damage. In rats with IQ-1S administration, the LCBF was significantly higher (by 60%) compared with that in the GCI control. Treatment with IQ-1S also decreases blood viscosity and endothelial dysfunction. A concentration-dependent decrease (IC₅₀ = 0.8 ± 0.3 μM) of tone in isolated carotid arterial rings constricted with phenylephrine was observed after IQ-1S application in vitro. We also found that IQ-1S decreased the intensity of the lipid peroxidation in the brain tissue in rats with GCI. 2.2-Diphenyl-1-picrylhydrazyl scavenging for IQ-1S in acetonitrile and acetone exceeded the corresponding values for ionol, a known antioxidant. Overall, these results suggest that the neuroprotective properties of IQ-1S may be mediated by improvement of cerebral microcirculation due to the enhanced vasorelaxation, beneficial effects on blood viscosity, attenuation of the endothelial dysfunction, and antioxidant/antiradical IQ-1S activity.

Routine low-dose continuous or nocturnal oxygen for people with acute stroke: three-arm Stroke Oxygen Supplementation RCT

BACKGROUND

Stroke is a major cause of death and disability worldwide. Hypoxia is common after stroke and is associated with worse outcomes. Oxygen supplementation could prevent hypoxia and secondary brain damage.

OBJECTIVES

(1) To assess whether or not routine low-dose oxygen supplementation in patients with acute stroke improves outcome compared with no oxygen; and (2) to assess whether or not oxygen given at night only, when oxygen saturation is most likely to be low, is more effective than continuous supplementation.

DESIGN

Multicentre, prospective, randomised, open, blinded-end point trial.

SETTING

Secondary care hospitals with acute stroke wards.

PARTICIPANTS

Adult stroke patients within 24 hours of hospital admission and 48 hours of stroke onset, without definite indications for or contraindications to oxygen or a life-threatening condition other than stroke.

INTERVENTIONS

Allocated by web-based minimised randomisation to: (1) continuous oxygen: oxygen via nasal cannula continuously (day and night) for 72 hours after randomisation at a flow rate of 3 l/minute if baseline oxygen saturation was ≤ 93% or 2 l/minute if > 93%; (2) nocturnal oxygen: oxygen via nasal cannula overnight (21:00-07:00) for three consecutive nights. The flow rate was the same as the continuous oxygen group; and (3) control: no routine oxygen supplementation unless required for reasons other than stroke.

MAIN OUTCOME MEASURES

Primary outcome: disability assessed by the modified Rankin Scale (mRS) at 3 months by postal questionnaire (participant aware, assessor blinded). Secondary outcomes at 7 days: neurological improvement, National Institutes of Health Stroke Scale (NIHSS), mortality, and the highest and lowest oxygen saturations within the first 72 hours. Secondary outcomes at 3, 6, and 12 months: mortality, independence, current living arrangements, Barthel Index, quality of life (European Quality of Life-5 Dimensions, three levels) and Nottingham Extended Activities of Daily Living scale by postal questionnaire.

RESULTS

In total, 8003 patients were recruited between 24 April 2008 and 17 June 2013 from 136 hospitals in the UK [continuous, n = 2668; nocturnal, n = 2667; control, n = 2668; mean age 72 years (standard deviation 13 years); 4398 (55%) males]. All prognostic factors and baseline characteristics were well matched across the groups. Eighty-two per cent had ischaemic strokes. At baseline the median Glasgow Coma Scale score was 15 (interquartile range 15-15) and the mean and median NIHSS scores were 7 and 5 (range 0-34), respectively. The mean oxygen saturation at randomisation was 96.6% in the continuous and nocturnal oxygen groups and 96.7% in the control group. Primary outcome: oxygen supplementation did not reduce disability in either the continuous or the nocturnal oxygen groups. The unadjusted odds ratio for a better outcome (lower mRS) was 0.97 [95% confidence interval (CI) 0.89 to 1.05; p = 0.5] for the combined oxygen groups (both continuous and nocturnal together) (n = 5152) versus the control (n = 2567) and 1.03 (95% CI 0.93 to 1.13; p = 0.6) for continuous versus nocturnal oxygen. Secondary outcomes: oxygen supplementation significantly increased oxygen saturation, but did not affect any of the other secondary outcomes.

LIMITATIONS

Severely hypoxic patients were not included.

CONCLUSIONS

Routine low-dose oxygen supplementation in stroke patients who are not severely hypoxic is safe, but does not improve outcome after stroke.

FUTURE WORK

To investigate the causes of hypoxia and develop methods of prevention.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN52416964 and European Union Drug Regulating Authorities Clinical Trials (EudraCT) number 2006-003479-11.

FUNDING DETAILS

This project was funded by the National Institute for Health Research (NIHR) Research for Patient Benefit and Health Technology Assessment programmes and will be published in full in Health Technology Assessment; Vol. 22, No. 14. See the NIHR Journals Library website for further project information.

Extending the time window for intravenous thrombolysis in acute ischemic stroke using magnetic resonance imaging-based patient selection

BACKGROUND

Intravenous thrombolysis with alteplase within a time window up to 4.5 h is the only approved pharmacological treatment for acute ischemic stroke. We studied whether acute ischemic stroke patients with penumbral tissue identified on magnetic resonance imaging 4.5-9 h after symptom onset benefit from intravenous thrombolysis compared to placebo.

METHODS

Acute ischemic stroke patients with salvageable brain tissue identified on a magnetic resonance imaging were randomly assigned to receive standard dose alteplase or placebo. The primary end point was disability at 90 days assessed by the modified Rankin scale, which has a range of 0-6 (with 0 indicating no symptoms at all and 6 indicating death). Safety end points included death, symptomatic intracranial hemorrhage, and other serious adverse events.

RESULTS

The trial was stopped early for slow recruitment after the enrollment of 119 (61 alteplase, 58 placebo) of 264 patients planned. Median time to intravenous thrombolysis was 7 h 42 min. The primary endpoint showed no significant difference in the modified Rankin scale distribution at day 90 (odds ratio alteplase versus placebo, 1.20; 95% CI, 0.63-2.27, P = 0.58). One symptomatic intracranial hemorrhage occurred in the alteplase group. Mortality at 90 days did not differ significantly between the two groups (11.5 and 6.8%, respectively; P = 0.53).

CONCLUSIONS

Intravenous alteplase administered between 4.5 and 9 h after the onset of symptoms in patients with salvageable tissue did not result in a significant benefit over placebo. (Supported by Boehringer Ingelheim, Germany; ISRCTN 71616222).

Intracerebroventricular Delivery of Recombinant NAMPT Deters Inflammation and Protects Against Cerebral Ischemia

Our previous study indicated that nicotinamide phosphoribosyltransferase (NAMPT) is released from cells and might be an important extracellular neuroprotective factor in brain ischemia. Here, we tested whether NAMPT protects against ischemic brain injury when administered directly into the intracerebroventricular (ICV) compartment of the cranium. Recombinant NAMPT protein (2 μg) was delivered ICV in mice subjected to 45-min middle cerebral artery occlusion (MCAO), and the effects on infarct volume, sensorimotor function, microglia/macrophage polarization, neutrophil infiltration, and BBB integrity were analyzed. The results indicate that ICV administration of NAMPT significantly reduced infarct volume, retained its beneficial properties even when ICV administration was delayed by 6 h after MCAO, and improved neurological outcomes. NAMPT treatment inhibited pro-inflammatory microglia/macrophages, promoted microglia/macrophage polarization toward the anti-inflammatory phenotype, and reduced the infiltration of neutrophils into the perilesional area after brain ischemia. In vitro studies indicated that multiple pro-inflammatory microglial markers/cytokines were downregulated while multiple anti-inflammatory microglial markers/cytokines were induced in primary microglial cultures treated with NAMPT protein. NAMPT treatment also fortified the blood-brain barrier (BBB), as shown by reduced extravascular leakage of the small-molecule tracer Alexa Fluor 555 Cadaverine and larger-sized endogenous IgGs into brain parenchyma. Thus, NAMPT may protect against ischemic brain injury partly through a novel anti-inflammatory mechanism, which in turn maintains BBB integrity and reduces the infiltration of peripheral inflammatory cells. Taken together, these results provide validation of recombinant NAMPT delivery into the extracellular space as a potential neuroprotective strategy for stroke.

Neural like cells and acetyl-salicylic acid alter rat brain structure and function following transient middle cerebral artery occlusion

Introduction Transient cerebral ischemia is a pandemic neurological disorder and the main aim of medical intervention is to reduce complications. Human umbilical cord mesenchymal cells (hUCMs) are capable of differentiating into neural-like cells (NLC) in vitro, therefore we investigated the neuroprotective potential of these cells in comparison to aspirin and in combination (NLC-Aspirin) on spatial memory and neural morphologic changes in male rats submitted to transient cerebral ischemia. Methods Ten days after the intervention, the improvement in learning and memory were assessed in the animals by Morris Water Maze. Thence, the animals were examined for the presence of PKH26 labeled cells in the ischemic area of the brain, the infarct volume and neural changes in the brain tissue. Results Significant spatial memory deficits in the ischemic animals were detected compared with the control animals. The learning and memory were significantly improved (p ≤ 0.05) in the aspirin and NLC groups compared with the ischemic animals. Co-treatment of aspirin and NLCs did not improve the outcome. Moreover, infarction volume and neural changes were significantly altered when aspirin or NLCs were administered. Conclusions Our data suggest the significant neuroprotective potential of aspirin and neural-like cells derived from hUCM cells in the treatment of brain ischemic stroke. Further studies are required to evaluate possible underlying mechanisms, and to evaluate the possible interactions between aspirin and stem cells in a joint treatment aimed at the recovery of cognitive impairments.

[Neurogenesis and gliogenesis modulation in cerebral ischemia by CDK5 RNAi-based therapy]

INTRODUCTION

Cerebral ischemia is the third cause of death risk in Colombia and the first cause of physical disability worldwide. Different studies on the silencing of the cyclin-dependent kinase 5 (CDK5) have shown that reducing its activity is beneficial in ischemic contexts. However, its effect on neural cell production after cerebral ischemia has not been well studied yet.

OBJECTIVE

To evaluate CDK5 silencing on the production of neurons and astrocytes after a focal cerebral ischemia in rats.

MATERIALS AND METHODS

We used 40 eight-week-old male Wistar rats. Both sham and ischemia groups were transduced at CA1 hippocampal region with an adeno-associated viral vector using a noninterfering (shSCRmiR) and an interfering sequence for CDK5 (shCDK5miR). We injected 50 mg/kg of bromodeoxyuridine intraperitoneally from hour 24 to day 7 post-ischemia. We assessed the neurological abilities during the next 15 days and we measured the immunoreactivity of bromodeoxyuridine (BrdU), doublecortin (DCX), NeuN, and glial fibrillary acid protein (GFAP) from day 15 to day 30 post-ischemia.

RESULTS

Our findings showed that CDK5miR-treated ischemic animals improved their neurological score and presented increased BrdU+ cells 15 days after ischemia, which correlated with higher DCX and lower GFAP fluorescence intensities, and, although mature neurons populations did not change, GFAP immunoreactivity was still significantly reduced at 30 days post-ischemia in comparison with untreated ischemic groups.

CONCLUSION

CDK5miR therapy generated the neurological recovery of ischemic rats associated with the induction of immature neurons proliferation and the reduction of GFAP reactivity at short and longterm post-ischemia.

Sustained (S)-roscovitine delivery promotes neuroprotection associated with functional recovery and decrease in brain edema in a randomized blind focal cerebral ischemia study

Stroke is a devastating disorder that significantly contributes to death, disability and healthcare costs. In ischemic stroke, the only current acute therapy is recanalization, but the narrow therapeutic window less than 6 h limits its application. The current challenge is to prevent late cell death, with concomitant therapy targeting the ischemic cascade to widen the therapeutic window. Among potential neuroprotective drugs, cyclin-dependent kinase inhibitors such as (S)-roscovitine are of particular relevance. We previously showed that (S)-roscovitine crossed the blood-brain barrier and was neuroprotective in a dose-dependent manner in two models of middle cerebral artery occlusion (MCAo). According to the Stroke Therapy Academic Industry Roundtable guidelines, the pharmacokinetics of (S)-roscovitine and the optimal mode of delivery and therapeutic dose in rats were investigated. Combination of intravenous (IV) and continuous sub-cutaneous (SC) infusion led to early and sustained delivery of (S)-roscovitine. Furthermore, in a randomized blind study on a transient MCAo rat model, we showed that this mode of delivery reduced both infarct and edema volume and was beneficial to neurological outcome. Within the framework of preclinical studies for stroke therapy development, we here provide data to improve translation of pre-clinical studies into successful clinical human trials.

Ubiquitin Fusion Degradation Protein 1 as a Blood Marker for the Early Diagnosis of Ischemic Stroke

Background

Efficacy of thrombolysis in acute ischemic stroke is strongly related to physician's ability to make an accurate diagnosis and to intervene within 3–6 h after event onset. In this context, the discovery and validation of very early blood markers have recently become an urgent, yet unmet, goal of stroke research. Ubiquitin fusion degradation protein 1 is increased in human postmortem CSF, a model of global brain insult, suggesting that its measurement in blood may prove useful as a biomarker of stroke.

Methods

Enzyme-linked immunosorbent assay (ELISA) was used to measure UFD1 in plasma and sera in three independent cohorts, European (Swiss and Spanish) and North-American retrospective analysis encompassing a total of 123 consecutive stroke and 90 control subjects.

Results

Highly significant increase of ubiquitin fusion degradation protein 1 (UFD1) was found in Swiss stroke patients with 71% sensitivity (95% CI, 52–85.8%), and 90% specificity (95% CI, 74.2–98%) ( N = 31, p < 0.0001). Significantly elevated concentration of this marker was then validated in Spanish ( N = 39, p < 0.0001, 95% sensitivity (95% CI, 82.7– 99.4%)), 76% specificity (95% CI, 56.5–89.7%)) and North-American stroke patients ( N = 53, 62% sensitivity (95% CI, 47.9–75.2%), 90% specificity (95% CI, 73.5–97.9%), p < 0.0001). Its concentration was increased within 3 h of stroke onset, on both the Swiss ( p < 0.0001) and Spanish ( p = 0.0004) cohorts.

Conclusions

UFD1 emerges as a reliable plasma biomarker for the early diagnosis of stroke, and in the future, might be used in conjunction with clinical assessments, neuroimaging and other blood markers.

European Cooperative Acute Stroke Study-4: Extending the time for thrombolysis in emergency neurological deficits ECASS-4: ExTEND

RATIONALE AND HYPOTHESIS

Thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) is an effective and approved therapy for acute ischemic stroke within 4.5 h of onset except for USA, Canada, Croatia, and Moldovia with a current 3 h label. We hypothesized that ischemic stroke patients selected with significant penumbral mismatch on magnetic resonance imaging (MRI) at 4.5-9 h after onset of stroke will have improved clinical outcomes when given intravenous rt-PA (alteplase) compared to placebo.

STUDY DESIGN

ECASS-4: ExTEND is an investigator driven, phase 3, randomized, multi-center, double-blind, placebo-controlled study. Ischemic stroke patients presenting within 4.5 and 9 h of stroke onset, who fulfil clinical requirements (National Institutes of Health Stroke Score (NIHSS) 4-26 and pre-stroke modified Rankin Scale (mRS) 0-1) will undergo MRI. Patients who meet imaging criteria (infarct core volume <100 ml, perfusion lesion: infarct core mismatch ratio >1.2 and perfusion lesion minimum volume of 20 ml) additionally will be randomized to either rt-PA or placebo.

STUDY OUTCOME

The primary outcome measure will be the categorical shift in the mRS at day 90. Clinical secondary outcomes will be disability at day 90 dichotomized as favorable outcome mRS 0-1 at day 90. Tertiary endpoints include reduction in the NIHSS by 11 or more points or reaching 0-1 at day 90, reperfusion and recanalization at 24 h post stroke as well as depression, life quality, and cognitive impairment at day 90. Safety endpoints will include symptomatic intracranial hemorrhage (ICH) and death.

Alteplase for the treatment of acute ischaemic stroke: a NICE single technology appraisal; an evidence review group perspective

The National Institute for Health and Care Excellence (NICE) invited Boehringer Ingelheim GmbH, the manufacturer of alteplase, to submit evidence for the clinical and cost-effectiveness of alteplase for the prevention of strokes within a 0-4.5 h window. The comparator was standard medical and supportive management that does not include alteplase. This paper provides a description of the company submission, the Evidence Review Group (ERG) review and NICE's subsequent decisions. Clinical effectiveness evidence for alteplase was derived from 5 trials. For the 3-4.5 h treatment window, alteplase did not show a statistically significant treatment effect on death or dependency at three months follow-up. For the 0-4.5 h treatment window data from a meta-analysis of 3 trials indicated that the reduction of death and dependency was statistically significant. In both cases there was a significant increase in symptomatic intracranial haemorrhage. The economic model described in the manufacturer's submission was considered by the ERG to meet the NICE reference case. The model structure was considered to be appropriate and the ERG has no major concerns regarding the selection of data used within the model. The incremental cost-effectiveness ratios (ICER) for all treatment windows were well below accepted willingness to pay thresholds. The ERG had no major concerns regarding the completeness of the submission or the robustness of the evidence presented. For all treatment windows considered, alteplase was found to be cost-effective compared with standard treatment.

The Stroke Oxygen Study (SO2S) - a multi-center, study to assess whether routine oxygen treatment in the first 72 hours after a stroke improves long-term outcome: study protocol for a randomized controlled trial

BACKGROUND

Mild hypoxia is common in stroke patients and may have significant adverse effects on the ischemic brain after stroke. The use of oxygen treatment is rapidly increasing in European stroke units but is not without side effects. It impedes early mobilization, could pose an infection risk, and may encourage the formation of toxic free radicals, leading to further damage to the ischemic brain. In the Stroke Oxygen Pilot Study (2 or 3 L/min for 72 hours) neurological recovery at one week was better in the oxygen group than in controls, and after correction for difference in baseline stroke severity and prognostic factors, there was a trend to better outcome with oxygen at six months. Oxygen was as effective in mild as in severe strokes.Oxygen saturation is lower at night than during the day, and episodes of oxygen desaturation are common during sleep. Nocturnal oxygen supplementation is likely to reduce the burden of hypoxia without interfering with daytime mobilization and rehabilitation.Before wider use of oxygen supplementation becomes established it is important to obtain better evidence on which patients benefit from such treatment.

METHODS

Participants will be randomized to one of three groups: the first will receive continuous oxygen for 72 hours (at a rate of 2 or 3 L/min depending on baseline oxygen saturation), the second group will receive nocturnal oxygen only (at a rate of 2 or 3 L/min depending on baseline oxygen saturation) and the third group will not receive any oxygen (control). A baseline assessment is performed at randomization and a one-week follow-up completed. Outcome data at three, six and twelve months will be obtained via a questionnaire sent to the patient by the trial center.

DISCUSSION

This study will provide evidence on the effectiveness of oxygen supplementation for the treatment of stroke and whether nocturnal oxygen is a potentially beneficial therapy regimen.

TRIAL REGISTRATION

This trial is registered with the ISRCTN register ID number ISRCTN52416964.

Recruitment to trials of late thrombolysis: lessons from the EXTEND study

To increase the percentage of acute stroke patients benefiting from thrombolysis, the utility of expanding the time window of treatment beyond 4.5 hours after stroke onset needs to be investigated. We aimed to identify the target population and the challenges of recruitment of patients for the time window beyond 4.5 hours. Extending the time for Thrombolysis in Emergency Neurological Deficits (EXTEND), a multicentre randomised controlled trial testing the efficacy of thrombolytic therapy in patients with clinically significant ischaemic penumbra between 4.5 to 9 hours after stroke onset, was used as a model to evaluate inclusion and exclusion criteria for late thrombolysis trials. Data from all stroke patients admitted to Austin Health over a 1 year period were retrospectively analysed. Case notes were examined to determine potential trial eligibility. Of 556 patients assessed, 95 (17%) presented during the EXTEND time window. Sixty-seven of these (70.5%) were wake-up strokes (WUS) and 28 (29.5%) arrived between 4.5 and 9 hours after symptoms onset. At least one exclusion criterion was found for 78 (82%) of them. Hence, 17 (3%) patients arrived within an appropriate time frame for the study without any exclusion criteria. Most of these (13) arrived outside routine MRI hours. The number of patients recruited would have increased more than three-fold if imaging had been available 24 hours, 7 days a week. A significant proportion (17%) of ischaemic stroke patients presented between 4.5 and 9 hours after stroke onset. The majority of these were WUS. The major challenge identified for patient recruitment was imaging availability.

Bilateral common carotid artery occlusion as an adequate preconditioning stimulus to induce early ischemic tolerance to focal cerebral ischemia

There is accumulating evidence, that ischemic preconditioning - a non-damaging ischemic challenge to the brain - confers a transient protection to a subsequent damaging ischemic insult. We have established bilateral common carotid artery occlusion as a preconditioning stimulus to induce early ischemic tolerance to transient focal cerebral ischemia in C57Bl6/J mice. In this video, we will demonstrate the methodology used for this study.

Advanced imaging to extend the therapeutic time window of acute ischemic stroke

Reperfusion therapy for acute stroke has evolved from the initial use of intravenous tissue plasminogen activator (tPA) within 3 hours of symptom onset to more recent guideline-recommended use up to 4.5 hours. In addition, endovascular therapy is increasingly utilized for stroke treatment and is typically initiated up to 8 hours after onset. Recent studies demonstrate that imaging of the ischemic penumbra with diffusion/perfusion magnetic resonance imaging (MRI) can identify subgroups of patients who are likely to improve following successful reperfusion (Target Mismatch profile) and others who are at increased risk for hemorrhage and poor clinical outcomes (Malignant profile). New data indicate that stent retriever devices provide better recanalization efficacy and clinical outcomes than the previously available mechanical thrombectomy devices. Going forward, we believe that the use of penumbral imaging with validated MRI techniques, as well as the currently less well-validated computed tomography (CT) perfusion approach, will maximize benefit and reduce the risk of adverse events and poor outcomes when used both early after stroke onset and at later time points. New trials that feature diffusion/perfusion MRI or CT perfusion-based patient selection for treatment with intravenous tPA and or endovascular therapies versus nonreperfused control groups are planned or in progress. We predict that these trials will confirm the hypothesis that penumbral imaging can enhance patient selection and extend the therapeutic time window for acute ischemic stroke.

Fundamental interstrain differences in cortical activity between Wistar and Sprague-Dawley rats during global ischemia

Four-vessel occlusion (4VO), a frequently used model of global cerebral ischemia in rats, results in a dysfunction in wide brain areas, including the cerebral cortex and hippocampus. However, there are pronounced differences in response to global ischemia between the laboratory rat strains used in these studies. In the present work, the immediate acute effects of 4VO-induced global ischemia on the spontaneous electrocorticogram (ECoG) signals were analyzed in Wistar and Sprague-Dawley rats. The ECoG was isoelectric during the 10 min of global cerebral ischemia in Wistar rats and the first burst (FB) was seen 10-13 min after the start of reperfusion. In Sprague-Dawley rats, the FB was detected immediately after the start of 4VO or a few seconds later. The burst suppression ratio (BSR) in Wistar rats decreased to 45% in 5 min after FB, and after 25 min it was approximately 40%. In Sprague-Dawley rats, the BSR was 55% immediately after the FB and it decreased steeply to reach 0% by 10 min. There was also a significant difference between the two strains in the frequency composition of the ECoG pattern. The power spectral densities of the two strains differed virtually throughout the post-ischemic state. The histological results (Evans Blue, Cresyl Violet and Fluoro Jade C stainings) supplemented the electrophysiological data: the neuronal damage in the CA1 pyramids in Wistar rats was severe, whereas in the Sprague-Dawley animals it was only partial. These observations clearly demonstrate that the use of different rat strains (e.g. Wistar vs. Sprague-Dawley) can be a source of considerable variability in the results of acute experiments on global ischemia and it is important that the laboratory rats used in such experiments should be carefully chosen.

Isolation of inflammatory cells from rat brain tissue after stroke

The pathophysiology of sterile inflammation following focal ischemic stroke is complex and not fully understood, but there is growing evidence that it offers several therapeutic options beyond the hitherto existing treatment strategies. The identification and quantification of infiltrating inflammatory cells in animal models of stroke is crucial both for understanding post-stroke inflammation and for drug target identification. Multicolor flow cytometry plays an important role in determining subtypes and quantity of leukocytes that infiltrate the brain tissue after stroke. Until now, most investigations have been performed in mice, most likely due to a significantly broader spectrum of disposable antibodies and available knockout models. Here, we introduce a specific and reproducible method to isolate leukocytes from rat brain specimen in the context of brain ischemia to ultimately allow multi-dimensional flow cytometric characterization and further downstream methods such as cell-subtype sorting and molecular biological approaches.

Blood glutathione S-transferase-π as a time indicator of stroke onset

Background

Ability to accurately determine time of stroke onset remains challenging. We hypothesized that an early biomarker characterized by a rapid increase in blood after stroke onset may help defining better the time window during which an acute stroke patient may be candidate for intravenous thrombolysis or other intravascular procedures.

Methods

The blood level of 29 proteins was measured by immunoassays on a prospective cohort of stroke patients (N = 103) and controls (N = 132). Mann-Whitney U tests, ROC curves and diagnostic odds ratios were applied to evaluate their clinical performances.

Results

Among the 29 molecules tested, GST-π concentration was the most significantly elevated marker in the blood of stroke patients (p<0.001). More importantly, GST-π displayed the best area under the curve (AUC, 0.79) and the best diagnostic odds ratios (10.0) for discriminating early (N = 22, <3 h of stroke onset) vs. late stroke patients (N = 81, >3 h after onset). According to goal-oriented distinct cut-offs (sensitivity(Se)-oriented: 17.7 or specificity(Sp)-oriented: 65.2 ug/L), the GST-π test obtained 91%Se/50%Sp and 50%Se/91%Sp, respectively. Moreover, GST-π showed also the highest AUC (0.83) and performances for detecting patients treated with tPA (N = 12) compared to ineligible patients (N = 103).

Conclusions

This study demonstrates that GST-π can accurately predict the time of stroke onset in over 50% of early stroke patients. The GST-π test could therefore complement current guidelines for tPA administration and potentially increase the number of patients accessing thrombolysis.

Acute stroke centre - the changing focus of stroke unit care. The Bergen NORSTROKE Study

OBJECTIVES

The basic stroke unit studies selected patients primarily for rehabilitation and did not deal with the critical first hours after stroke. The aim of this study was to analyse a unselected cohort of patients admitted to an acute stroke centre with primary focus on emergency diagnosis and treatment.

MATERIALS AND METHODS

All patients with suspected stroke were admitted as emergencies. Patients with definite cerebrovascular disease were prospectively included in the Bergen Stroke Study, patients with other diseases were excluded, but final diagnosis was registered.

RESULTS

Fifty per cent of the admitted patients had other diagnosis than stroke. Of 1267 consecutive patients with cerebrovascular disease, 70% had no or minor neurological deficits on admission. After 1 week, 56% were independent, 30% needed long-term rehabilitation, 10% were bedridden and 4% were dead.

CONCLUSION

An acute stroke centre today requires a high degree of neurological expertise in assessing patients admitted with possible stroke. Most patients with stroke have no or mild deficits and need above all rapid diagnostic work-up, acute and prophylactic treatment. In-hospital rehabilitation is essential for a smaller number of patients who suffer from persisting neurological deficits after stroke.

A multicentre, randomized, double-blinded, placebo-controlled Phase III study to investigate EXtending the time for Thrombolysis in Emergency Neurological Deficits (EXTEND)

BACKGROUND AND HYPOTHESIS

Thrombolytic therapy with tissue plasminogen activator is effective for acute ischaemic stroke within 4·5 h of onset. Patients who wake up with stroke are generally ineligible for stroke thrombolysis. We hypothesized that ischaemic stroke patients with significant penumbral mismatch on either magnetic resonance imaging or computer tomography at three- (or 4·5 depending on local guidelines) to nine-hours from stroke onset, or patients with wake-up stroke within nine-hours from midpoint of sleep duration, would have improved clinical outcomes when given tissue plasminogen activator compared to placebo.

STUDY DESIGN

EXtending the time for Thrombolysis in Emergency Neurological Deficits is an investigator-driven, Phase III, randomized, multicentre, double-blind, placebo-controlled study. Ischaemic stroke patients presenting after the three- or 4·5-h treatment window for tissue plasminogen activator and within nine-hours of stroke onset or with wake-up stroke within nine-hours from the midpoint of sleep duration, who fulfil clinical (National Institutes of Health Stroke Score ≥4-26 and prestroke modified Rankin Scale <2) will undergo magnetic resonance imaging or computer tomography. Patients who also meet imaging criteria (infarct core volume <70 ml, perfusion lesion : infarct core mismatch ratio >1·2, and absolute mismatch >10 ml) will be randomized to either tissue plasminogen activator or placebo.

STUDY OUTCOME

The primary outcome measure will be modified Rankin Scale 0-1 at day 90. Clinical secondary outcomes include categorical shift in modified Rankin Scale at 90 days, reduction in the National Institutes of Health Stroke Score by 8 or more points or reaching 0-1 at day 90, recurrent stroke, or death. Imaging secondary outcomes will include symptomatic intracranial haemorrhage, reperfusion and or recanalization at 24 h and infarct growth at day 90.

Therapeutic neuroprotective effects of XQ-1H in a rat model of permanent focal cerebral ischemia

Cerebral ischemia is one of the leading causes for death and severe disabilities in the world. XQ-1H exerts neuroprotective effects under various neurotoxic conditions in vitro. In vivo, it reduces brain damage after transient focal cerebral ischemia. The present study evaluated the dose effectiveness and therapeutic time window of neuroprotection of XQ-1H by behavioral and histological measures in rats subjected to permanent middle cerebral artery occlusion (pMCAO). Neurological deficits, TTC stain, brain water content, necrosis neuron counts, and Evans-Blue extravasation were used to quantify brain damage and blood-brain barrier dysfunction. Our results demonstrated that postischemic treatment with XQ-1H at a dose of 31.2 mg/kg produced a significant reduction in neurological scores when treatment was initiated within 2 h of pMCAO. A similar improvement was also observed in infarct volume, brain water content, Evans-Blue extravasation, and neuronal necrosis when treatment was initiated within 1 h of pMCAO. Treatment with XQ-1H at the dose of 15.6 mg/kg within 1 h also produced significant improvement in ischemia deficit. In conclusion, the therapeutic time window of XQ-1H extends for up to 1 h after pMCAO, and treatment with XQ-1H exhibits potent neuroprotection that may be of value for the design of stroke therapies.

Surgical treatment of patients with unilateral cerebellar infarcts: clinical outcome and prognostic factors

BACKGROUND

There are limited data on the long-term outcome and on factors influencing the prognosis in patients with cerebellar infarcts treated with surgical decompression.

METHODS

Thirty-two patients (age 64.3 ± 9.9 years) with expansive unilateral cerebellar infarcts were retrospectively evaluated. All patients were treated with ventriculostomy, suboccipital decompressive craniectomy and removal of the necrotic tissue. The Glasgow Coma Scale (GCS) and the Reaction Level Scale (RLS) scores evaluated the level of consciousness during hospitalization, while the modified Rankin Scale (mRS) was used for the 6-month and long-term outcome. Predicting factors were analyzed using a univariate logistic regression model.

RESULTS

The median time from ictus to surgery was 48.4 h (range 8-120 h). Before surgery, the median GCS score was 9 (3-13). At discharge, the GCS score improved to 13.6 (7-15) (p < 0.05 compared to preoperative scores). At the long-term follow-up (median 67.5 months), ten patients were dead, and 77% of survivors had a good outcome (mRS score of ≤2). The number of days on a ventilator and the GCS score prior to surgery and at discharge were strong predictors of clinical outcome (p < 0.05), although one third of patients with a GCS ≤ 8 at the time of surgery had a good long-term outcome. In patients ≥70 years old, 50% had a good long-term outcome, and advanced age was not associated with a bad result (p > 0.05).

CONCLUSIONS

Our results imply that surgical evacuation of significant cerebellar infarctions may be considered also in patients with advanced age and/or a decreased level of consciousness.

Combined systemic thrombolysis with alteplase and early hyperbaric oxygen therapy in experimental embolic stroke in rats: relationship to functional outcome and reduction of structural damage

INTRODUCTION

The only causal therapy in ischemic stroke is thrombolysis with recombinant tissue plasminogen activator (rtPA), but it is feasible only for few patients, and new therapies are needed. This study investigates the effects of systemic thrombolysis with rtPA combined with hyperbaric oxygen therapy (HBOT) in embolic stroke in rats.

METHODS

In 22 male Wistar rats, an embolic ischemic stroke was induced. The animals were randomized to one of four groups: control, thrombolysis alone, HBOT sequential or HBOT parallel with thrombolysis. HBOT (2.4 ATA, 1 h) started 45 min (sequential) or 120 min (parallel) after stroke. rtPA was given intravenously 120 min after stroke onset. Functional tests were performed after stroke induction and after treatment. After 6 h infarct volume and intracerebral hemorrhagic complications were assessed.

RESULTS

Compared to the control group only the combination of HBOT and thrombolysis significantly improved the functional outcome (p=0.03) and reduced the infarct volume (p=0.01), whereas thrombolysis alone did not show a significant benefit. In all treatment groups there was a trend towards fewer hemorrhagic transformations.

CONCLUSION

Hyperbaric oxygen in combination with thrombolysis shows neuroprotection in acute ischemic stroke in rats by reducing infarct volume and improving functional outcome in the early poststroke period.

Short-latency crossed spinal responses are impaired differently in sub-acute and chronic stroke patients

OBJECTIVE

Investigate if patients with supraspinal lesions have impaired interlimb spinal reflex pathways. The short-latency crossed spinal response will be investigated during sitting from the non-paretic to paretic and paretic to non-paretic extremities at different stimulation intensities in chronic and sub-acute stroke patients.

METHODS

The ipsilateral tibial nerve of the paretic and non-paretic extremities were stimulated at motor threshold, 35% M-max and 85% M-max of the ipsilateral soleus while the contralateral soleus was contracted from 5% to 15% of the maximum voluntary contraction of the paretic soleus.

RESULTS

Chronic patients (from both extremities) had significantly less prominent inhibitory responses than healthy controls (post hoc tests: P<.01-P<.05). The responses were significantly modulated by stimulus intensity in healthy controls and chronic patients (P<.001-P<.05) but not sub-acute patients (P>.05). Some sub-acute patients had significantly more variable responses than chronic patients and healthy controls (P<.001-P⩽.05).

CONCLUSIONS

Short-latency interlimb reflexes are impaired differently in sub-acute vs. chronic patients, are impaired from the non-paretic and paretic extremity, and abnormal when compared to healthy controls.

SIGNIFICANCE

The inappropriate coordination could result in an inability to quickly avoid obstacles following a mechanical disturbance to the ipsilateral extremity. It also indicates that bilateral descending projections affect the response.

Classification for carotid artery stenting complications: manifestation, management, and prevention

Carotid artery stenting is a rapidly evolving method for treating carotid artery disease. Various intraprocedural and postprocedural complications have been reported in the literature. However, the absence of a unified classification scheme for these complications makes it difficult, if not impossible, to study their precise incidence, predictors, and management. The aim of this article is to propose the first joint classification of periprocedural complications, to analyze their incidence and etiology, and suggest possible ways to manage and prevent them. This classification is intended to be used as a common platform for prompt recognition, evaluation, treatment, and universal study of the complications during carotid stenting procedures. For this purpose, the opinions of the major experts on carotid interventions worldwide were merged with all the available information reported in the English-language literature to present as accurately as possible the management and prevention of carotid stenting complications according to this proposed classification.

Protective role of COMP-Ang1 in ischemic rat brain

In cerebral ischemia, the induction of angiogenesis may represent a natural defense mechanism that enables the hypoxic brain to avoid progression into infarction. Angiopoietin-1 (Ang1) is known to produce non-leaky and stable blood vessel formation mainly by the Tie2 receptor. Therefore, we envisioned that the application of cartilage oligomeric matrix protein-Ang1 (COMP-Ang1), a soluble, stable, and potent form of Ang1, would promote angiogenesis and provide a protective effect following unilateral middle cerebral artery occlusion (MCAO) in rats. To this end, we employed a 2-hour-MCAO model, and treated rats with adenovirus encoding COMP-Ang1 (Ade-COMP-Ang1) or control virus encoding beta-gal (Ade-beta-gal). Time course magnetic resonance images (MRIs) revealed significantly reduced infarct volume in the rats treated with Ade-COMP-Ang1 with an improvement of post-ischemic neurological deficits compared with rats treated with Ade-beta-gal. Moreover, compared to the rats treated with Ade-beta-gal, the rats treated with Ade-COMP-Ang1 showed an increase in blood vessels, especially in the border zone adjacent to the infarction, increased number of endogenous neuronal progenitor cells in the ischemic brain, and decreased number of TUNEL-positive cells. Taken together, COMP-Ang1 reduced infarct volume and consequently attenuated post-ischemic neurological deficits through enhanced angiogenesis and increased viable cell mass of neuronal cells.

Thromboembolism in atrial fibrillation

Thromboembolism is a severe complication in atrial fibrillation. This overview presents thromboembolic disease as a single entity, ranging from stroke through mesenteric ischemia to acute limb ischemia. The PubMed, Embase, and Cochrane databases were systematically searched for the terms "atrial fibrillation" and "thromboembolism" in reports published from January 1986 to September 2009. The information of 10 evidence-based practice guideline documents and 61 further sources was systematically extracted. In atrial fibrillation, the average annual stroke risk is increased by 2.3% (lethality 30%). The annual incidence of acute mesenteric ischemia is 0.14% (lethality 70%), and that of acute limb ischemia is 0.4% (lethality 16%). In total, approximately 80% of embolism-related deaths are from stroke and 20% from other systemic thromboembolism. The ischemic symptoms generally have an acute onset but may mimic other diseases, particularly in mesenteric ischemia. Early diagnosis and treatment can limit or even prevent tissue infarction. Guideline-recommended therapy with aspirin or warfarin reduces the thromboembolic risk. Suitable patients may optimize their warfarin therapy by self-monitoring of the international normalized ratio (INR). New oral and parenteral anticoagulants with more stable pharmacokinetics are being developed. In conclusion, atrial fibrillation predisposes to thromboembolism. If ischemic stroke or systemic thromboembolism occurs, early diagnosis and treatment can improve outcomes. The thromboembolic risks are reduced by guideline-adherent antithrombotic therapy with warfarin or aspirin. Future directions may include self-monitoring of the international normalized ratio and novel anticoagulants.

A review of the evidence for the use of telemedicine within stroke systems of care: a scientific statement from the American Heart Association/American Stroke Association

The aim of this new statement is to provide a comprehensive and evidence-based review of the scientific data evaluating the use of telemedicine for stroke care delivery and to provide consensus recommendations based on the available evidence. The evidence is organized and presented within the context of the American Heart Association's Stroke Systems of Care framework and is classified according to the joint American Heart Association/American College of Cardiology Foundation and supplementary American Heart Association Stroke Council methods of classifying the level of certainty and the class of evidence. Evidence-based recommendations are included for the use of telemedicine in general neurological assessment and primary prevention of stroke; notification and response of emergency medical services; acute stroke treatment, including the hyperacute and emergency department phases; hospital-based subacute stroke treatment and secondary prevention; and rehabilitation.

Emergency department evaluation and management of stroke: acute assessment, stroke teams and care pathways

The emergency department (ED) is the entry point into the health care system for many stroke victims. Rapid evaluation, diagnosis and treatment of stroke in the prehospital setting as well as the ED are integral to preventing morbidity and mortality. In some centers, emergency medicine physicians are the health care professionals most often able to provide thrombolytic therapy to stroke patients during the brief three-hour window for this therapy. An organized ED approach including implementing stroke care pathways and collaborating with specialized stroke teams in the ED enhance the ability to identify and manage stroke patients effectively. This approach has the potential to improve outcomes on a large scale.

Bacterial endocarditis in a child presenting with acute arterial ischemic stroke: should thrombolytic therapy be absolutely contraindicated?

Thrombolysis is considered to be contraindicated in acute ischemic stroke secondary to infective endocarditis (IE). We report a 12-year-old female who presented with acute dense right hemiparesis and aphasia. Cranial magnetic resonance imaging and angiography showed multiple diffusion-restricted lesions in the left hemisphere and absence of flow in the left internal carotid artery. She was treated with intra-arterial tissue plasminogen activator within 6 hours of her presentation. Subsequently she was diagnosed with pneumococcal endocarditis and underwent debridement of vegetations and patch repair of the mitral valve. The patient did not have hemorrhagic complications following thrombolytic therapy or surgery. Pathological analysis of the mitral valve vegetations revealed mostly fibrin thrombus. Follow-up imaging showed complete recanalization of the left internal carotid artery, and the patient had a remarkable neurological recovery. This is the first case report of successful intra-arterial thrombolytic therapy in childhood IE-related stroke. We believe that thrombolytic therapy contributed to a favorable outcome in our patient and may be safe in selected patients with childhood IE-related acute ischemic stroke.

Improving clinical trials of long-term outcomes

There is an increasing evidence that survivors of critical illness suffer from impaired health-related quality of life. There are relatively few studies that have evaluated the effect of interventions in clinical trials to improve these long-term outcomes. Studies to improve long-term outcomes after critical illness face many of the same challenges encountered in studies designed to improve shorter term outcomes in the intensive care unit. These include an incomplete understanding of the causal mechanisms involved in post-intensive care unit impairment, trouble in identifying patients ill enough to benefit from an intervention but whose impairment is not fixed, and identifying proper outcome variables. There are, however, unique challenges to clinical trials including bias from competing mortality and incomplete follow-up. Research interest in developing interventions to improve long-term outcome after critical illness is in its infancy and it is too early to make strong clinical recommendations. Multiple potential treatment areas exist, both within the intensive care unit and after patients leave the hospital, for intensivists to target. Those interested in this area should collaborate to build on the lessons from effective multidisciplinary programs developed to treat other diseases.

Hyperglycaemia and neurological injury

PURPOSE OF REVIEW

Clinical and experimental data suggest that hypergylcaemia lowers the ischaemic neuronal threshold and worsens outcome in the presence of neurological injury from trauma, stroke and subarachnoid haemorrhage. This review aims to appraise the evidence for tight glycaemic control in patients with neurological injury.

RECENT FINDINGS

Hyperglycaemia can adversely affect outcome in critically ill patients. Intensive insulin therapy with tight glycaemic control has been advocated for improving outcome in these patients. However, the extent to which intensive insulin therapy and tight control of blood glucose improve outcome after ischaemic neurological insults remains unclear. The benefit of such treatment regimes may be negated by the increased frequency of hypoglycaemic episodes, which may aggravate neurological injury. Although it seems sensible to control hyperglycaemia in patients with neurological injury, the treatment must account for potential hypoglycaemic episodes.

SUMMARY

Clinical and experimental data suggest that hyperglycaemia lowers the ischaemic neuronal threshold in the presence of neurological injury. Tight glycaemic control may result in hypoglycaemia, which in itself can be detrimental. Therefore, it seems sensible that we should accept slightly less tight blood glucose control than in the critically ill patient without neurological injury.

The neuroprotective effect of prostaglandin E2 EP1 receptor inhibition has a wide therapeutic window, is sustained in time and is not sexually dimorphic

We investigated the preclinical characteristics of the neuroprotective effect of the prostaglandin E2 type 1 receptor (EP1) antagonist SC51089 in models of focal cerebral ischemia produced by occlusion of the mouse middle cerebral artery (MCA). We found that systemic administration of SC51089 (5 to 20 microg/kg; i.p.) reduces the brain injury produced by transient (-50%+/-8%; n=12; P<0.05) or permanent (-39%+/-7%; n=12; P<0.05) MCA occlusion. SC51089 was effective even when administered up to 12 h after ischemia. The protective effect was observed both in male and female mice and was sustained for at least 2 weeks after induction of ischemia. The reduction in injury volume was associated with an improvement in neurological function assessed by the Bederson deficit score, the hanging wire test and the corner test. The data provide proof of principle that EP1 receptor inhibition is a potentially valuable strategy for neuroprotection that deserves further preclinical investigation for therapeutic application in human stroke.

Cell adhesion molecules and ischemic stroke

OBJECTIVE

To describe the role of adhesion molecules in ischemic stroke.

METHODS

A PubMed search of literature pertaining to this study was conducted in April 2008 using specific keyword search terms pertaining to stroke and various listed subtopics related to adhesion molecules.

RESULTS

An important contribution of beta2-integrins (CD11/CD18), intercellular adhesion molecule and P-selectin in the recruitment of leukocytes as well as platelets in the post-ischemic cerebral microvasculature has been defined in related studies. Immunoblockade or genetic deletion of these adhesion molecules has been shown to reduce infarct volume, edema, behavioral deficits and/or mortality in different animal models of ischemic stroke. Anti-adhesion agents also appear to widen the therapeutic window for thrombolytic therapy in these experimental models. An emerging role of inflammatory signaling pathways has also been addressed in modulating adhesion properties of post-ischemic cerebral microvasculature. Despite the promising data obtained from animal studies, few clinical trials assessing anti-adhesion therapy in ischemic stroke have failed to show efficacy.

DISCUSSION

Several experiments using cell surface adhesion molecules as targets of stroke therapy are promising yet inadequate. Clinical trials using immune blockade of adhesion molecules by antibodies have failed due to immune reactions of the host. Further clinical trials are needed to test the efficacy of humanized antibodies or non-immunogenic agents that interfere with cell adhesion mechanisms. Adhesion blocking strategies seem to be effective particularly at reperfusion and use of these strategies with thrombolytic therapies justifies a continued effort to define the role of adhesion molecules in the pathophysiology of cerebral ischemia-reperfusion.

Carboxypeptidase U (TAFIa) decreases the efficacy of thrombolytic therapy in ischemic stroke patients

INTRODUCTION

Thrombolytic therapy improves clinical outcome in patients with acute ischemic stroke but is compromised by symptomatic intracranial hemorrhage and an unpredictable therapeutic response. In vitro and in vivo data suggest that activation of procarboxypeptidase U (proCPU) inhibits fibrinolysis.

AIMS

To investigate whether the extent of proCPU activation is related to efficacy and safety of thrombolytic therapy in ischemic stroke patients.

METHODS

In twelve patients with ischemic stroke who were treated with intravenous (n=7) or intra-arterial (n=5) thrombolysis, venous blood samples were taken at different time points before, during and after thrombolytic therapy. ProCPU and carboxypeptidase U (CPU, TAFIa) plasma concentrations were determined by HPLC. The maximal CPU activity (CPU(max)) and the percentage of proCPU consumption during thrombolytic therapy were calculated. The efficacy and safety of the thrombolytic therapy were assessed by evolution of the clinical deficit, recanalisation, final infarct volume, thrombolysis-induced intracranial hemorrhage and mortality.

RESULTS

No correlations between CPU(max) or proCPU consumption and patient or stroke characteristics were found. However, CPU(max) is associated with evolution of the clinical deficit and achieved recanalisation. ProCPU consumption is related to the risk of intracranial hemorrhage, mortality and final infarct volume.

CONCLUSIONS

Irrespective of patient and stroke characteristics, CPU(max) and proCPU consumption during thrombolytic treatment for ischemic stroke are parameters for therapeutic efficacy and safety. Further evaluation of the clinical applicability of these parameters and further investigation of the potential role for CPU inhibitors as adjunctive therapeutics during thrombolytic treatment may be of value.

Stroke-induced immunodepression: consequences, mechanisms and therapeutic implications

The clinical picture of stroke is not only characterized by neurological deficits but also by the high incidence of infectious complications, in particular pneumonia. The occurrence of pneumonia in stroke patients is associated with higher mortality, larger neurological deficits, longer hospitalization and increased costs for medical care. Immobilization and impaired protective reflexes are known to increase the risk of aspiration pneumonia. However, recent experimental and clinical evidence indicates that stroke-induced immunodepression is an independent risk factor that increases susceptibility to infections. This review provides an update on the mechanisms and consequences of stroke-induced immunodepression. The growing insight into these mechanisms may allow new immunomodulatory treatment approaches in stroke patients in the future. In the meantime, several trials on preventive antibacterial treatment to reduce the incidence of post-stroke infections have been conducted, which will be summarized in this review.