Oral antiplatelet therapy for acute ischaemic stroke

The Coagulation Factor XIIa Inhibitor rHA-Infestin-4 Improves Outcome after Cerebral Ischemia/Reperfusion Injury in Rats

Background and Purpose

Ischemic stroke provokes severe brain damage and remains a predominant disease in industrialized countries. The coagulation factor XII (FXII)-driven contact activation system plays a central, but not yet fully defined pathogenic role in stroke development. Here, we investigated the efficacy of the FXIIa inhibitor rHA-Infestin-4 in a rat model of ischemic stroke using both a prophylactic and a therapeutic approach.

Methods

For prophylactic treatment, animals were treated intravenously with 100 mg/kg rHA-Infestin-4 or an equal volume of saline 15 min prior to transient middle cerebral artery occlusion (tMCAO) of 90 min. For therapeutic treatment, 100 mg/kg rHA-Infestin-4, or an equal volume of saline, was administered directly after the start of reperfusion. At 24 h after tMCAO, rats were tested for neurological deficits and blood was drawn for coagulation assays. Finally, brains were removed and analyzed for infarct area and edema formation.

Results

Within prophylactic rHA-Infestin-4 treatment, infarct areas and brain edema formation were reduced accompanied by better neurological scores and survival compared to controls. Following therapeutic treatment, neurological outcome and survival were still improved although overall effects were less pronounced compared to prophylaxis.

Conclusions

With regard to the central role of the FXII-driven contact activation system in ischemic stroke, inhibition of FXIIa may represent a new and promising treatment approach to prevent cerebral ischemia/reperfusion injury.

Platelet-derived VWF in the stroke spotlight

In this issue of Blood, Verhenne et al present data showing the role of platelet-derived von Willebrand factor (VWF) in mediating ischemic stroke injury using a murine model. They created mice with either endothelial VWF or platelet-derived VWF and examined each phenotype for bleeding and thrombosis. Their intriguing findings were that mice lacking platelet-derived VWF, but with adequate endothelial VWF stores, demonstrated normal hemostasis in a tail bleeding model and normal carotid artery thrombosis. Mice with only platelet-derived VWF had defective hemostasis and defective carotid artery thrombosis, but experienced significant cerebral infarction using a stroke model with middle cerebral artery occlusion (see figure). In contrast, minimal infarcts were seen for VWF-deficient mice. These data suggest that platelet-derived VWF plays a specific role in stroke pathology.

Aspirin and multiple sclerosis

Aspirin is widely used to lessen the risks of cardiovascular events. Some studies suggest that patients with multiple sclerosis have an increased risk for some cardiovascular events, for example, venous thromboembolism and perhaps ischemic strokes, raising the possibility that aspirin could lessen these increased risks in this population or subgroups (patients with limited mobility and/or antiphospholipid antibodies). However, aspirin causes a small increased risk of hemorrhagic stroke, which is a concern as it could potentially worsen a compromised blood-brain barrier. Aspirin has the potential to ameliorate the disease process in multiple sclerosis (for example, by limiting some components of inflammation), but aspirin also has the potential to inhibit mitochondrial complex I activity, which is already reduced in multiple sclerosis. In an experimental setting of a cerebral ischemic lesion, aspirin promoted the proliferation and/or differentiation of oligodendrocyte precursors, raising the possibility that aspirin could facilitate remyelination efforts in multiple sclerosis. Other actions by aspirin may lead to small improvements of some symptoms (for example, lessening fatigue). Here we consider potential benefits and risks of aspirin usage by patients with multiple sclerosis.

Cerebrolysin for acute ischaemic stroke

BACKGROUND

Cerebrolysin is a mixture of low-molecular-weight peptides and amino acids derived from pigs' brain tissue, which has potential neuroprotective and neurotrophic properties. It is widely used in the treatment of acute ischaemic stroke in Russia, China, and other Asian and post-Soviet countries.

OBJECTIVES

To assess the benefits and risks of Cerebrolysin for treating acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (October 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (November 2014), MEDLINE (1966 to November 2014), EMBASE (1974 to November 2014), Web of Science Core Collection, with Science Citation Index (1940 to November 2014), LILACS (1982 to December 2014), OpenGrey (1980 to December 2014), and a number of Russian Databases (1998 to December 2014). We also searched reference lists, ongoing trials registers and conference proceedings, and contacted the manufacturer of Cerebrolysin, EVER Neuro Pharma GmbH (formerly Ebewe Pharma).

SELECTION CRITERIA

Randomised controlled trials comparing Cerebrolysin started within 48 hours of stroke onset and continued for at least two weeks with placebo or no treatment in people with acute ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied inclusion criteria, assessed trial quality and risk of bias, and extracted data.

MAIN RESULTS

We included one trial involving 146 participants. We evaluated risk of bias and judged it to be high for generation of allocation sequence, low for allocation concealment, high for incomplete outcome data (attrition bias), unclear for blinding, high for selective reporting and high for other sources of bias. The manufacturer of Cerebrolysin, pharmaceutical company Ebewe, provided Cerebrolysin and the placebo, as well as the randomisation codes. There was no difference in the number of deaths (6/78 in Cerebrolysin group versus 6/68 in placebo group; risk ratio (RR) 0.87, 95% confidence interval (CI) 0.29 to 2.58) or in the total number of adverse events (16.4% versus 10.3%; RR 1.62, 95% CI 0.69 to 3.82) between the treatment and control groups.

AUTHORS' CONCLUSIONS

Routine administration of Cerebrolysin to people with acute ischaemic stroke cannot be supported by the available evidence from RCTs.

Mailuoning for acute ischaemic stroke

BACKGROUND

Mailuoning is widely used in the treatment of acute ischaemic stroke in China. Animal experimental studies and clinical pharmacological research indicate that mailuoning might improve blood circulation, prevent ischaemic injury, and protect heart and brain tissue. This review was last published in 2009. As new data have become available, it is necessary to reassess the evidence from randomised controlled trials.

OBJECTIVES

To determine the effects and safety of mailuoning agents (injection or oral liquid) in the treatment of people with acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (May 2014), the Cochrane Central Register of Controlled Trials (CENTRAL;2014, Issue 4), MEDLINE (1966 to May 2014), Embase (1980 to May 2014), AMED (1985 to May 2014), the Chinese Stroke Trials Register (June 2014), the China Biological Medicine Database (CBM-disc; 1979 to June 2014), China Science and Technology Journal database (CSTJ; 1979 to June 2014), Wanfang Data Chinese databases (1979 to June 2014), and the China National Knowledge Infrastructure (1979 to June 2014). We searched clinical trials and research registers, handsearched 10 Chinese journals including relevant conference proceedings, scanned reference lists, and contacted the pharmaceutical company that manufactures mailuoning. We also attempted to contact trial authors to obtain further data.

SELECTION CRITERIA

Randomised controlled trials comparing mailuoning with placebo or mailuoning plus other treatment compared with that other treatment in people with acute ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data.

MAIN RESULTS

We included 21 trials, involving 1746 participants, in this update; six trials were new. The included trials did not report the numbers of dead and dependent participants at the end of at least three months' follow-up. Of the 12 trials that reported adverse events, five events occurred in two trials. There was no significant difference between the treatment group and the control group. We assessed 20 trials to be of a poor quality: When analysing these trials together, mailuoning was associated with a significant increase in the number of participants with an improved neurological deficit (risk ratio (RR) 0.31, 95% confidence interval (CI) 0.23 to 0.42) and showed a significant improvement of neurological deficit with the European Stroke Scale (ESS) (mean difference (MD) (fixed) 8.29, 95% CI 3.44 to 13.15). One placebo-controlled trial, assessed to be of a better methodological quality, failed to show a significant improvement of neurological deficit at the end of three months' follow-up (MD (fixed) 2.49, 95% CI -1.45 to 6.43) or in quality of life. One trial, which reported cognitive function using the Montreal Cognitive Assessment as a continuous scale, showed a significant improvement of cognitive function (MD (fixed) 2.68, 95% CI 1.82 to 3.54). Two trials assessed activities of daily life: One trial showed a significant improvement, but the other did not.

AUTHORS' CONCLUSIONS

This review did not provide sufficient evidence to support the routine use of mailuoning for the treatment of people with acute ischaemic stroke. High-quality large-scale randomised controlled trials are needed to confirm the efficacy of mailuoning.