The N-methyl-D-aspartate antagonist CNS 1102 protects cerebral gray and white matter from ischemic injury following temporary focal ischemia in rats

BACKGROUND AND PURPOSE: Cerebral white matter is as sensitive as gray matter to ischemic injury and is probably amenable to pharmacological intervention. In this study we investigated whether an N-methyl-D-aspartate (NMDA) antagonist, CNS 1102, protects not only cerebral gray matter but also white matter from ischemic injury. METHODS: Ten rats underwent 15 minutes of temporary focal ischemia and were blindly assigned to CNS 1102 intravenous bolus injection (1. 13 mg/kg) followed by intravenous infusion (0.33 mg/kg per hour) for 3.75 hours or to vehicle (n=5 per group) immediately after reperfusion. Seventy-two hours after ischemia, the animals were perfusion fixed for histology. The severity of neuronal necrosis in the cortex and striatum was semiquantitatively analyzed. The Luxol fast blue-periodic acid Schiff stain and Bielschowsky\u27s silver stain were used to measure optical densities (ODs) of myelin and axons, respectively, in the internal capsule of both hemispheres, and the OD ratio was calculated to reflect the severity of white matter damage. RESULTS: Neuronal damage in both the cortex and the striatum was significantly better in the drug-treated group than in the placebo group (P\u3c0.05). The OD ratio of both the axons (0.93+/-0.08 versus 0.61+/-0.18; P\u3c0.01) and the myelin sheath (0.95+/-0.07 versus 0.67+/-0.19; P=0.01) was significantly higher in the CNS 1102 group than in the placebo group. The neurological score was significantly improved in the drug-treated group (P\u3c0.05). CONCLUSIONS: The NMDA receptor antagonist CNS 1102 protects not only cerebral gray matter but also white matter from ischemic injury, most probably by preventing degeneration of white matter structures such as myelin and axons

Synergistic effects of a combination of low-dose basic fibroblast growth factor and citicoline after temporary experimental focal ischemia

BACKGROUND AND PURPOSE: Basic fibroblast growth factor (bFGF) and citicoline (cytidine 5\u27-diphosphate choline, an endogenous compound that stabilizes membrane function) have demonstrated neuroprotective effects after focal cerebral ischemia. Both agents are candidates for future stroke therapy in humans. For evaluation of synergistic effects of bFGF and citicoline, a low-dose combination of both compounds was tested against each compound alone and placebo. METHODS: Four groups of Sprague-Dawley rats (n=12 per group) underwent 90 minutes of focal cerebral ischemia with the use of the suture model of middle cerebral artery occlusion. Animals were randomly and blindly assigned to one of the following treatment groups: placebo, low-dose citicoline (250 mg/kg IP daily for 4 days), low-dose bFGF (10 microg/kg per hour IV for 3 hours), and the combination of both (250 mg/kg citicoline and 10 microg/kg per hour bFGF). Triphenyltetrazolium chloride staining was used after 4 days to determine postmortem infarction. Neurological scores were assessed on a daily basis. RESULTS: The premature mortality rate was 41.7% in the placebo and citicoline groups, 33.3% in the bFGF group, and 25% (P=NS) in the combination group. The mean neurological score on day 4 was 3.1+/-1.6 (placebo), 3.1+/-1.6 (citicoline), 2.9+/-1.5 (bFGF), and 2.4+/-1.4 (combination) (P=NS). The mean volume of infarction was significantly reduced in the combination group (136. 5+/-25.4 mm3) versus placebo (172.6+/-48.9 mm3; P=0.036, Fisher test), versus citicoline alone (186.0+/-35.7 mm3; P=0.005, Fisher test), and versus bFGF alone (176.0+/-49.2 mm3; P=0.023, Fisher test). CONCLUSIONS: These results demonstrate synergistic effects of a low-dose combination of the growth factor bFGF and citicoline after temporary experimental focal cerebral ischemia and furthermore support the effectiveness of a combination treatment regimen for the management of acute stroke

Perspectives on neuroprotective stroke therapy

After years of setbacks, the perspective of neuroprotective stroke therapy has revived in light of recent study results. We outline in this review how a neuroprotective candidate drug should be developed, beginning with a thorough preclinical evaluation according to the STAIR (Stroke Therapy Academic Industry Roundtable) criteria. Assessing the safety of the candidate drug in the relatively straightforward Phase IIA would be the first step into clinical development. While advancing into Phase IIB, the implementation of a responder analysis, the use of a surrogate biomarker as well as the use of Bayesian methodology should be considered to increase the likelihood of seeing any therapeutic sign. Clinical development in Phase III should consider that previously used dichotomized endpoints appropriate for evaluation of thrombolytic drugs are likely to be insufficient for assessing efficacy of neuroprotective drugs. Detection of a clinically relevant shift in the outcome measure appears to be a more relevant approach for the type of drug that achieves a reduction and not a reverse of the ischaemic lesion

Focused ultrasound and NXY-059 in experimental cerebral ischemia: A new therapeutic opportunity?

troke is the third leading cause of morbidity and mortality worldwide. Many deleterious cellular pathways have been proposed to explain the molecular pathogenesis of this clinically devastating disease [1, 2]. The pathophysiology of stroke is complex and involves not only calcium and glutamate-mediated excitotoxicity but also various inflammatory pathways, disturbance of ionic balance, increased production of free radicals and neuronal cell apoptosis [3-5]. Besides its critical role for ion homeostasis in the central nervous system, disturbance of BBB integrity plays a significant role in stroke pathogenesis [6-8]. In this respect, recent studies have established that loss of BBB integrity and secondary loss of ion regulation may lead to brain edema and subsequent brain damage after cerebral ischemia [7, 9, 10]. This suggests that stabilization of the BBB could be brain protective, although recent studies failed to confirm this [11-13]. Moreover, data show that cerebral ischemia-induced BBB disruption is increased by 24 hours after middle cerebral artery occlusion [14], thus providing only a short window for transport of macromolecular drugs into the infarcted brain [14, 15]. This therapeutic time-frame effectively limits treatment efficacy due to an inability to achieve a sufficiently high dose of drug in the target brain area [15]. Therapeutic agents are often difficult to administer to the brain due to BBB prevention of passage for systemically administered molecules and proteins [16-18]. Because of this pharmacological therapies have made limited progress, and much effort is now being directed to identify compounds that accumulate more efficaciously in the diseased brain

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

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 mug/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 \u3e 14-17 cm(3). 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