Granulocyte colony-stimulating factor in patients with acute ischemic stroke: results of the AX200 for Ischemic Stroke trial.

BACKGROUND AND PURPOSE: Granulocyte colony-stimulating factor (G-CSF; AX200; Filgrastim) is a stroke drug candidate with excellent preclinical evidence for efficacy. A previous phase IIa dose-escalation study suggested potential efficacy in humans. The present large phase IIb trial was powered to detect clinical efficacy in acute ischemic stroke patients. METHODS: G-CSF (135 µg/kg body weight intravenous over 72 hours) was tested against placebo in 328 patients in a multinational, multicenter, randomized, and placebo-controlled trial (NCT00927836; www.clinicaltrial.gov). Main inclusion criteria were ≤9-hour time window after stroke onset, infarct localization in the middle cerebral artery territory, baseline National Institutes of Health Stroke Scale score range of 6 to 22, and baseline diffusion-weighted imaging lesion size ≥15 mL. Primary and secondary end points were the modified Rankin scale score and the National Institutes of Health Stroke Scale score at day 90, respectively. Data were analyzed using a prespecified model that adjusted for age, National Institutes of Health Stroke Scale score at baseline, and initial infarct volume (diffusion-weighted imaging). RESULTS: G-CSF treatment failed to meet the primary and secondary end points of the trial. For additional end points such as mortality, Barthel index, or infarct size at day 30, G-CSF did not show efficacy either. There was, however, a trend for reduced infarct growth in the G-CSF group. G-CSF showed the expected peripheral pharmacokinetic and pharmacodynamic profiles, with a strong increase in leukocytes and monocytes. In parallel, the cytokine profile showed a significant decrease of interleukin-1. CONCLUSIONS: G-CSF, a novel and promising drug candidate with a comprehensive preclinical and clinical package, did not provide any significant benefit with respect to either clinical outcome or imaging biomarkers. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00927836.

AXIS: a trial of intravenous granulocyte colony-stimulating factor in acute ischemic stroke.

BACKGROUND AND PURPOSE: Granulocyte colony-stimulating factor (G-CSF) is a promising stroke drug candidate. The present phase IIa study assessed safety and tolerability over a broad dose range of G-CSF doses in acute ischemic stroke patients and explored outcome data. METHODS: Four intravenous dose regimens (total cumulative doses of 30-180 µg/kg over the course of 3 days) of G-CSF were tested in 44 patients in a national, multicenter, randomized, placebo-controlled dose escalation study (NCT00132470; www.clinicaltrial.gov). Main inclusion criteria were a 12-hour time window after stroke onset, infarct localization to the middle cerebral artery territory, a baseline National Institutes of Health Stroke Scale range of 4 to 22, and presence of diffusion-weighted imaging/perfusion-weighted imaging mismatch. RESULTS: Concerning the primary safety end points, we observed no increase of thromboembolic events in the active treatment groups, and no increase in related serious adverse events. G-CSF led to expected increases in neutrophils and monocytes that resolved rapidly after end of treatment. We observed a clinically insignificant drug-related decrease of platelets. As expected from the low number of patients, we did not observe significant differences in clinical outcome in treatment vs. placebo. In exploratory analyses, we observed an interesting dose-dependent beneficial effect of treatment in patients with DWI lesions > 14-17 cm³. CONCLUSIONS: We conclude that G-CSF was well-tolerated even at high dosages in patients with acute ischemic stroke, and that a substantial increase in leukocytes appears not problematic in stroke patients. In addition, exploratory analyses suggest treatment effects in patients with larger baseline diffusion-weighted imaging lesions. The obtained data provide the basis for a second trial aimed to demonstrate safety and efficacy of G-CSF on clinical end points.

The safety of fiberoptic endoscopic evaluation of swallowing in acute stroke patients.

BACKGROUND AND PURPOSE: Fiberoptic endoscopic evaluation of swallowing (FEES) is an excellent method for the accurate examination of swallowing function in the acute phase of stroke. The present study investigates the safety of FEES related to patients characteristics in a setting of acute stroke care. METHODS: A prospective study of FEES-associated complications was carried out in 300 acute stroke patients over a 1-year period. A neurologist and a speech-language pathologist of the stroke unit team performed FEES within a mean time interval of 1.9+/-0.8 days after stroke onset. A closely meshed monitoring of cardiovascular parameters was done during each examination. A discomfort rating was obtained from the patients. RESULTS: In none of the 300 subjects any airway comprise, decrease in the level of consciousness, symptomatic bradycardia/tachycardia, laryngospasm, or epistaxis requiring special treatment was observed. The incidence of self-limiting nosebleeds was 6% and did not significantly differ in relation to major stroke types (ischemic versus hemorrhagic), acute treatment strategy (thrombolysis versus no thrombolysis), or secondary prevention regime (anticoagulant therapy versus antiplatelet drugs). Whereas no alterations in diastolic blood pressure were noted, statistically significant changes in systolic blood pressure, heart rate, and oxygen saturation occurred. However, these alterations did not cause any severe adverse event and were clinically judged as being mild. The assessment of comfort revealed an excellent tolerance of FEES in >80% of patients. CONCLUSIONS: This study demonstrates that FEES is a well-tolerated and safe method to assess swallowing function when performed by a speech-language pathologist and a neurologist in a stroke unit setting.

Towards a basic endoscopic evaluation of swallowing in acute stroke - identification of salient findings by the inexperienced examiner.

BACKGROUND: Dysphagia is common after stroke. Fiberoptic endoscopic evaluation of swallowing (FEES) is a powerful tool for dysphagia assessment. The purpose of this study was to assess whether a previously established endoscopic examination protocol based on the identification of typical findings indicative of stroke - related dysphagia may be learned and adopted by clinicians so far inexperienced in this field. METHODS: After receiving a structured lecture on this topic, participants were asked to rate video sequences of endoscopic swallowing examinations of acute stroke patients. The first part of the testing ("single findings-rating") comprised of 16 single sequences, the second part ("complete examination-rating") presented the key sequences of 8 complete examinations. Before the second part was started, results of the first were discussed. RESULTS: At the "single findings-rating" 88.8% of video-sequences were assessed correctly, while at the "complete examination-rating" the average performance had improved to 96%. Furthermore, no overlooking of relevant pathologies was noted in the second part of the testing. CONCLUSION: This study suggests that the presented endoscopic examination protocol is reliably interpreted by inexperienced clinicians after a short lecture and may therefore easily and successfully be adopted in dysphagia management of acute stroke care.

Towards a basic endoscopic assessment of swallowing in acute stroke - development and evaluation of a simple dysphagia score.

BACKGROUND AND PURPOSE: Dysphagia is an important complication of acute stroke with a reported incidence of up to 76%. The purpose of this investigation was to develop and to evaluate an endoscopic scoring system which has the potential to guide dysphagia management in acute stroke patients. METHODS: A fiberoptic endoscopic evaluation of swallowing (FEES) was carried out in 100 patients within 72 h of stroke onset. During endoscopic examination, the secretion status was evaluated, and the patient was successively given standard volumes of puree consistency, liquids and soft solid food. Penetration and aspiration was assessed using a 5-point scale. RESULTS: Nearly 80% of patients showed penetration or aspiration during FEES. These events occurred more frequently with liquids and soft solid food than with puree. Penetration or aspiration at any stage of examination predicted failure at the subsequent food consistency. Furthermore, key findings of endoscopic evaluation were predictive of the need for later orotracheal intubation. Based on these observations a score was developed that grades stroke-related dysphagia according to the risk of penetration or aspiration of the different food consistencies tested. Assessment of interrater reliability by means of 25 additional endoscopic examinations resulted in excellent agreement between three investigators, reflected by a kappa coefficient of 0.89. CONCLUSION: Stroke-related dysphagia may effectively be graded using a simple endoscopic scoring system. The usefulness of this screening protocol with respect to patient outcome and intercurrent complications has to be studied in prospective clinical trials.

Positional sleep apnea in patients with ischemic stroke.

BACKGROUND: In non-stroke patients, the severity of sleep apnea (SA) is known to be frequently related to the sleeping position, a condition called positional SA. In the present study, we investigated whether in acute stroke the occurrence of apneas was related to the positioning of patients, and whether a similar finding could be observed after rehabilitation. With the purpose of identifying patients potentially being in need of a SA treatment beyond rehabilitation, we furthermore looked for epidemiologic and clinical parameters being related to persistent SA 6 months after stroke. PATIENTS AND METHODS: Fifty-five acute stroke patients underwent cardiorespiratory polygraphy within 72 hours after onset of neurological symptoms and after 6 months. Apart from the total AHI (AHITOT), the AHI with the patient in supine position and the AHI with the patient in other positions were determined. In all patients, demographic data, NIH-stroke scale score and cumulative vascular risk factors were assessed. RESULTS: In the initial sleep study, 78% of patients had an AHI>or=10/h, of whom 65% fulfilled the criteria of positional SA. On follow-up, the incidence of SA declined to 49% with positional SA being present in 33%. Multivariate logistic regression analysis identified AHITOT on admission [OR=1.07 (1.002-1.13)] and cumulative vascular risk factors [OR=3.48 (1.34-9.05)] as independent predictors of persistent SA 6 months after stroke. CONCLUSION: According to our results, positional SA is a predominant feature in acute stroke and its incidence decreases significantly during the following months. These findings may have implications for SA treatment in patients with acute stroke.

A new model of thromboembolic stroke in the posterior circulation of the rat.

The prognosis of vertebrobasilar occlusion is grave and therapeutic options are limited. The aim of the present study was to develop a new model of embolic hindbrain ischemia in the rat that closely resembles the clinical situation and that can be used to study pathophysiology and treatment options. After thoracotomy in 20 male Wistar rats, 15 animals received an injection of in vitro prepared autologous blood clots into the left vertebral artery. Five animals without clot injection served as controls. Neurological deficits were assessed in all animals 2 h after embolism. After 2 h, five animals were sacrificed to measure cerebral blood flow (CBF) by iodo-antipyridine autoradiography, and to calculate early cerebellar swelling by comparison of both hemispheres in brain slices. In these animals, autoradiography revealed ipsilesional brain swelling and significantly reduced blood flow values relative to the contralateral (unaffected) structures. Immunohistology showed the typical pattern of focal cerebral ischemia in the brain stem and/or cerebellum in 7 of 10 animals allowed to recover to 24 h. Hence, successful thromboembolism was achieved in 12 of 15 animals (80%). With this novel model, the pathophysiology and potential treatments of posterior circulation stroke can be investigated.

Release of fatty acid amides in a patient with hemispheric stroke: a microdialysis study.

BACKGROUND: Excitotoxic insults such as stroke may induce release of fatty acid ethanolamides (FAEs), contributing to the downstream events in the ischemic cascade. We therefore studied release of FAEs such as anandamide, palmitylethanolamide (PEA), and oleylethanolamide (OEA) in the brain of a patient suffering from malignant hemispheric infarction treated with hypothermia. CASE DESCRIPTION: A patient with life-threatening hemispheric stroke was treated with moderate hypothermia (33 degrees C) that was maintained for 3 days, followed by a 3-day rewarming period. Microdialysis was applied to measure glutamate, lactate, and glycerol by using a microdialysis analyzer. FAEs were measured by microdialysis coupled with high-performance liquid chromatography/mass spectrometry. Release of neuroprotective fatty amides occurred within the first day after ischemia and reached high concentrations for all 3 substances in tissue surrounding the primary ischemic lesion: anandamide up to 42 pmol/mL, PEA up to 120 pmol/mL, and OEA up to 242 pmol/mL. There was a significant correlation with elevation of lactate as early marker for the hypoxic insult. CONCLUSIONS: This is the first report demonstrating release of FAEs in vivo during human stroke and may suggest contribution of the FAE signaling system to the pathophysiological events after ischemia.

Atherosclerosis and obstructive sleep apnea in patients with ischemic stroke.

BACKGROUND: Of late, obstructive sleep apnea (OSA) has been suggested to be a risk factor for atherosclerotic artery disease. In the present study, we analyzed the prevalence of atherosclerosis in stroke patients with and without OSA. PATIENTS AND METHODS: Two hundred and fourteen consecutive patients with ischemic stroke were included in this study. Patients were screened for classical cerebrovascular risk factors. All patients received a cardiorespiratory polygraphy to determine the apnea-hypopnea index. Duplex ultrasonography was used to evaluate the carotid bulb and the internal carotid artery for the presence of atherosclerotic lesions, which were graded in 'none', 'plaques with <50% stenosis', 'stenosis > or =50% to subtotal', and 'occlusion'. RESULTS: Atherosclerotic lesions were identified in 42% of patients. These were significantly more prevalent in patients with OSA than in patients without. In multiple logistic regression analysis, this association was independent of other known vascular risk factors. Arterial hypertension, which was significantly related to atherosclerosis in univariate analysis, lost its statistical impact in multivariate analysis. CONCLUSION: This study confirms that OSA is an independent risk factor for atherosclerotic artery disease that may even outweigh the impact of arterial hypertension in selected patient collectives. To further elucidate this topic, treatment studies are needed that look for a possible improvement of markers and signs of atherosclerosis in patients with OSA.

C-reactive protein and fibrinogen in acute stroke patients with and without sleep apnea.

BACKGROUND AND PURPOSE: Although sleep apnea (SA) is a risk factor for ischemic stroke and an important prognosticator in affected patients, the exact pathophysiological link between SA and stroke remains to be established. We investigated whether levels of C-reactive protein (CRP) and fibrinogen are increased in patients with acute stroke and SA compared with stroke patients without SA. PATIENTS AND METHODS: 117 consecutive patients with ischemic stroke admitted to our stroke unit within 12 h after stroke onset were included in this study. On admission, CRP and fibrinogen levels were determined. All patients received cardiorespiratory polygraphy during the first 72 h of their hospital stay. In all patients, demographic data, National Institutes of Health Stroke Scale score and cerebrovascular risk factors were assessed. RESULTS: SA defined by an apnea-hypopnea index (AHI) of > or =10/h was found in 64 (55%) patients. Elevated CRP and fibrinogen levels were seen twice as often in patients with SA than in patients without (CRP: 52 vs. 26%; fibrinogen: 72 vs. 37%). After multivariate logistic regression analysis, an AHI of > or =10/h was independently correlated with raised levels of both of these parameters. CONCLUSION: SA is independently associated with raised levels of CRP and fibrinogen in patients with acute ischemic stroke. We assume that both proteins are part of the pathophysiological pathway linking SA to stroke.

Hypothermia and brain-derived neurotrophic factor reduce glutamate synergistically in acute stroke.

Moderate hypothermia and application of brain-derived neurotrophic factor (BDNF) have separately been identified as neuroprotective strategies in experimental cerebral ischemia. To assess their separate and combined effects on striatal glutamate release in the hyperacute phase of stroke, we inserted microdialysis probes into the striatum of rats 2 h before permanent middle cerebral artery occlusion (MCAO). The animals (N = 28) were randomly assigned to one of four treatment strategies commencing 30 min after MCAO: (1) hypothermia at 33 degrees C (n = 7); (2) intravenous BDNF infusion [300 microg/(kg/h) for 2 h, n = 7]; (3) combination of hypothermia and BDNF (n = 7); (4) control group (saline, n = 7). Infarct size at 5 h after MCAO was assessed with the silver-staining method. Total infarct volume was significantly reduced in the hypothermia (202.7 +/- 3.5 mm(3), P = 0.0002) and BDNF group (206.5 +/- 6.9 mm(3), P = 0.0006) as compared to control group (254.4 +/- 9.3 mm(3)). In the combination group, infarct size was further reduced with overall significance in post hoc tests (157.3 +/- 6.2 mm(3), P < 0.0001). Postischemic glutamate concentrations in the control group constantly remained significantly higher than in all other treatment groups. At 255 and 270 min after MCAO, striatal glutamate in the combination group decreased significantly more than in animals treated with hypothermia or BDNF alone.Combining hypothermia and BDNF therapy in the acute stage of ischemia has a synergistic effect in attenuating striatal glutamate release and reducing early infarct size.

Effects of intracerebroventricular application of brain-derived neurotrophic factor on cerebral recovery after cardiac arrest in rats.

SUBJECT: After transient global cerebral ischemia, selective vulnerable brain areas show delayed neurodegeneration with characteristics of apoptosis. Recent data demonstrate potent neuroprotective effects of the application of endogenous growth hormones such as brain-derived neurotrophic factor (BDNF) after focal cerebral ischemia. To assess possible effects of the intracerebroventricular application of BDNF on cerebral recovery after global cerebral ischemia due to cardiac arrest in rats, various selective vulnerable brain areas were investigated. INTERVENTIONS: Global cerebral ischemia was initiated by ventricular fibrillation in rats under general anesthesia. After 6 mins, the animals were resuscitated by external cardiac massage combined with defibrillation and divided into two groups (BDNF vs. placebo). BDNF or placebo (1 microg/hr) was applied continuously during the complete reperfusion time using an implanted osmotic minipump. After 6 hrs, 24 hrs, 3 days, and 7 days (n = 6-7 per group), coronal brain sections were analyzed by terminal deoxynucleotidyltransferase-mediated d-uracil triphosphate-biotin nick end-labeling (TUNEL) and Nissl staining and a caspase activity assay in the hippocampal cornu ammonis 1 sector, the nucleus reticularis thalami, and the striatum. At 24 hrs, 3 days, and 7 days, animals were tested according to a neurologic deficit score. MEASUREMENTS AND MAIN RESULTS: In all groups, typical delayed neurodegeneration was observed in selective vulnerable brain areas. Neuroscore, TUNEL, and Nissl staining revealed no relevant differences between the groups (BDNF vs. placebo) with regard to neurologic recovery and the number of viable (after 7 days in cornu ammonis 1 sector: BDNF, 110 +/- 32; placebo, 142 +/- 53) and TUNEL-positive neurons (after 7 days in cornu ammonis 1 sector: BDNF, 360 +/- 81; placebo, 253 +/- 62) during the different time points. CONCLUSIONS: Despite the well-known neuroprotective properties of BDNF in ischemic-induced neuronal degeneration, the present study did not reveal any beneficial effects regarding neurologic recovery and neurohistopathologic outcome after global cerebral ischemia in rats. Future investigations should focus on intracellular signaling cascades activated by BDNF after global cerebral ischemia.