Novel approaches to neuroprotection trials in acute ischemic stroke

Small extracellular vesicles administered directly in the brain promote neuroprotection and decreased microglia reactivity in a stroke mouse model

Herein, we investigate the bioactivity of small extracellular vesicles (sEVs), focusing on their local effect in the brain. sEVs from mononuclear cells (MNCs) showed superior effects in vitro to sEVs from mesenchymal stem cells (MSCs) and were able to promote neuroprotection and decrease microglia reactivity in a stroke mouse model.

Neuroprotective and Antioxidant Properties of CholesteroNitrone ChN2 and QuinolylNitrone QN23 in an Experimental Model of Cerebral Ischemia: Involvement of Necrotic and Apoptotic Cell Death

Ischemic stroke is the leading cause of disability and the second leading cause of death worldwide. However, current therapeutic strategies are scarce and of limited efficacy. The abundance of information available on the molecular pathophysiology of ischemic stroke has sparked considerable interest in developing new neuroprotective agents that can target different events of the ischemic cascade and may be used in combination with existing treatments. In this regard, nitrones represent a very promising alternative due to their renowned antioxidant and anti-inflammatory effects. In this study, we aimed to further investigate the neuroprotective effects of two nitrones, cholesteronitrone 2 (ChN2) and quinolylnitrone 23 (QN23), which have previously shown great potential for the treatment of stroke. Using an experimental in vitro model of cerebral ischemia, we compared their anti-necrotic, anti-apoptotic, and antioxidant properties with those of three reference compounds. Both ChN2 and QN23 demonstrated significant neuroprotective effects (EC₅₀ = 0.66 ± 0.23 μM and EC₅₀ = 2.13 ± 0.47 μM, respectively) comparable to those of homo-bis-nitrone 6 (HBN6) and N-acetylcysteine (NAC) and superior to those of α-phenyl-N-tert-butylnitrone (PBN). While primarily derived from the nitrones' anti-necrotic capacities, their anti-apoptotic effects at high concentrations and antioxidant powers-especially in the case of QN23-also contribute to their neuroprotective effects.

Adenosine A1R/A3R agonist AST-004 reduces brain infarction in mouse and rat models of acute ischemic stroke

Acute ischemic stroke (AIS) is the second leading cause of death globally. No Food and Drug Administration (FDA) approved therapies exist that target cerebroprotection following stroke. Our group recently reported significant cerebroprotection with the adenosine A1/A3 receptor agonist, AST-004, in a transient stroke model in non-human primates (NHP) and in a preclinical mouse model of traumatic brain injury (TBI). However, the specific receptor pathway activated was only inferred based on in vitro binding studies. The current study investigated the underlying mechanism of AST-004 cerebroprotection in two independent models of AIS: permanent photothrombotic stroke in mice and transient middle cerebral artery occlusion (MCAO) in rats. AST-004 treatments across a range of doses were cerebroprotective and efficacy could be blocked by A3R antagonism, indicating a mechanism of action that does not require A1R agonism. The high affinity A3R agonist MRS5698 was also cerebroprotective following stroke, but not the A3R agonist Cl-IB-MECA under our experimental conditions. AST-004 efficacy was blocked by the astrocyte specific mitochondrial toxin fluoroacetate, confirming an underlying mechanism of cerebroprotection that was dependent on astrocyte mitochondrial metabolism. An increase in A3R mRNA levels following stroke suggested an intrinsic cerebroprotective response that was mediated by A3R signaling. Together, these studies confirm that certain A3R agonists, such as AST-004, may be exciting new therapeutic avenues to develop for AIS.

Neuroprotection of everolimus against focal cerebral ischemia-reperfusion injury in rats

BACKGROUND

Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth and metabolism and integrates various signals under physiological and pathological conditions. Altered signaling of mTOR has been shown to play pathogenic roles in ischemic stroke. In the present study, the protective effect of everolimus, the selective mTOR inhibitor, in the middle cerebral artery occlusion (MCAO) model of ischemic stroke was evaluated.

METHODS

Wistar rats were exposed to MCAO (30 min) followed by reperfusion for 24 h. Everolimus (100, and 500 µg/kg) was administered at the time of reperfusion, intraperitoneally. 24 h post operation, the neurological function, infarct volume, histopathological alterations and the markers of oxidative stress including superoxide dismutase (SOD) activity, malondialdehyde (MDA), and total thiol levels were analyzed in the peri-infarct region.

RESULTS

In the rats subjected to MCAO, everolimus ameliorated neurological deficits, neuronal cell loss, and infarct volume, as compared to the stroke group. Also, everolimus significantly increased SOD activity and total thiol content, while markedly decreased the MDA level, as compared to MCAO group.

CONCLUSION

Single-dose administration of everolimus significantly improved neurological deficits and inhibited cortical cell loss by enhancing redox status, subsequently protected cerebral ischemia-reperfusion injury in rats.

A Systematic Review and Meta-Analysis of Statins in Animal Models of Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe form of stroke with limited treatment options. Statins have shown promise as a therapy for ICH in animal and human studies. We systematically reviewed and assessed the quality of preclinical studies exploring statin-use after ICH to guide clinical trial decision-making and design.

METHODS

We identified preclinical trials assessing the efficacy of statins in ICH via a systematic review of the literature according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In total, 16 studies were identified that described statin use in an animal model of ICH and assessed histological outcomes, behavioral scores, or both. Design characteristics were analyzed using Stroke Therapy Academic Industry Roundtable (STAIR) criteria modified for ICH. Meta-analysis was performed using a random effects model.

RESULTS

Behavioral outcomes were assessed in 12 of the studies with 100% (n = 12) reporting that statins significantly improved ICH recovery. Histologic hematoma volume and brain water content outcomes were analyzed in 10 of the studies, with 50% (n = 5) reporting significant improvement. The ratio of means between experimental and control cases for modified Neurological Severity Score was 0.63 (95% confidence interval 0.49-0.82). The ratio of means between experimental and control cases for hemorrhagic volume was 0.85 (95% confidence interval 0.70-1.03). There was heterogeneity between studies (P < 0.0001) but no evidence of publication bias (P = 0.89, P = 0.59, respectively).

CONCLUSIONS

Behavioral outcomes in ICH were found to consistently improve with administration of statins in preclinical studies suggesting that statin therapy may be suitable for randomized clinical trials in humans. In addition, the STAIR criteria can be modified to effectively evaluate preclinical studies in ICH.

Stroke Genetics: Turning Discoveries into Clinical Applications

The field of medical and population genetics in stroke is moving at a rapid pace and has led to unanticipated opportunities for discovery and clinical applications. Genome-wide association studies have highlighted the role of specific pathways relevant to etiologically defined subtypes of stroke and to stroke as a whole. They have further offered starting points for the exploration of novel pathways and pharmacological strategies in experimental systems. Mendelian randomization studies continue to provide insights in the causal relationships between exposures and outcomes and have become a useful tool for predicting the efficacy and side effects of drugs. Additional applications that have emerged from recent discoveries include risk prediction based on polygenic risk scores and pharmacogenomics. Among the topics currently moving into focus is the genetics of stroke outcome. While still at its infancy, this field is expected to boost the development of neuroprotective agents. We provide a brief overview on recent progress in these areas.

LncRNA H19 promotes inflammatory response induced by cerebral ischemia-reperfusion injury through regulating the miR-138-5p-p65 axis

Recent studies have shown that long non-coding RNA(LncRNA) H19 is up-regulated in the brain of rats suffering from cerebral ischemia-reperfusion (I/R) injury, inducing severe disability and mortality. Little was known about the molecular mechanisms underlying the involvement of H19 in cerebral I/R injury. In this study, a rat model of I/R was induced by transient middle cerebral artery occlusion (tMCAO). PC-12 cells exposed to oxygen and glucose deprivation/reoxygenation (OGD/R) were used as an in vitro model. Our results show that H19 is up-regulated in both in vivo and in our in vitro model. Further study indicated that knockdown of H19 promotes cell proliferation, decreases the rate of cell apoptosis, and ameliorates inflammation after OGD/R simulation. Our in vivo study shows that H19 knockdown ameliorates inflammation and improves neurological function in our rat model of tMCAO. Remarkably, the results from our luciferase reporter assays suggest that H19 negatively regulates the expression of miR-138-5p, and p65 was identified as a target of miR-138-5p. To sum up, this study demonstrated that H19 promotes an inflammatory response and improves neurological function in a rat model of tMCAO by regulating the expression of miR-138-5p and p65. This study reveals the important role and underlying mechanism of H19 in the progress of cerebral I/R injury, which could serve as a potential target for further treatment.

Mesenchymal stem cell-derived extracellular vesicle-based therapies protect against coupled degeneration of the central nervous and vascular systems in stroke

Stem cell-based treatments have been suggested as promising candidates for stroke. Recently, mesenchymal stem cells (MSCs) have been reported as potential therapeutics for a wide range of diseases. In particular, clinical trial studies have suggested MSCs for stroke therapy. The focus of MSC treatments has been directed towards cell replacement. However, recent research has lately highlighted their paracrine actions. The secretion of extracellular vesicles (EVs) is offered to be the main therapeutic mechanism of MSC therapy. However, EV-based treatments may provide a wider therapeutic window compared to tissue plasminogen activator (tPA), the traditional treatment for stroke. Exosomes are nano-sized EVs secreted by most cell types, and can be isolated from conditioned cell media or body fluids such as plasma, urine, and cerebrospinal fluid (CSF). Exosomes apply their effects through targeting their cargos such as microRNAs (miRs), DNAs, messenger RNAs, and proteins at the host cells, which leads to a shift in the behavior of the recipient cells. It has been indicated that exosomes, in particular their functional cargoes, play a significant role in the coupled pathogenesis and recovery of stroke through affecting the neurovascular unit (NVU). Therefore, it seems that exosomes could be utilized as diagnostic and therapeutic tools in stroke treatment. The miRs are small endogenous non-coding RNA molecules which serve as the main functional cargo of exosomes, and apply their effects as epigenetic regulators. These versatile non-coding RNA molecules are involved in various stages of stroke and affect stroke-related factors. Moreover, the involvement of aging-induced changes to specific miRs profile in stroke further highlights the role of miRs. Thus, miRs could be utilized as diagnostic, prognostic, and therapeutic tools in stroke. In this review, we discuss the roles of stem cells, exosomes, and their application in stroke therapy. We also highlight the usage of miRs as a therapeutic choice in stroke therapy.

Multiphase adjuvant neuroprotection: A novel paradigm for improving acute ischemic stroke outcomes

While several large pivotal clinical trials recently revealed a substantial benefit of endovascular thrombectomy for acute ischemic stroke (AIS) caused by large-vessel occlusion, many patients still experience mediocre prognosis. Enlargement of the ischemic core, failed revascularization, incomplete reperfusion, distal embolization, and secondary reperfusion injury substantially impact the salvaging of brain tissue and the functional outcomes of AIS. Here, we propose novel concept of “Multiphase Adjuvant Neuroprotection” as a new paradigm that may help guide our search for adjunctive treatments to be used together with thrombectomy. The premise of multiphase adjuvant neuroprotection is based on the diverse and potentially nonoverlapping pathophysiologic mechanisms that are triggered before, during, and after thrombectomy therapies. Before thrombectomy, strategies should focus on preventing the growth of the ischemic core; during thrombectomy, improving recanalization while reducing distal embolization and maximizing reperfusion are of significant importance; after reperfusion, strategies should focus on seeking targets to reduce secondary reperfusion injury. The concept of multiphase adjuvant neuroprotection, wherein different strategies are employed throughout the various phases of clinical care, might provide a paradigm to minimize the final infarct size and improve functional outcome in AIS patients treated with thrombectomy. With the success of thrombectomy in selected AIS patients, there is now an opportunity to revisit stroke neuroprotection. Notably, if the underlying mechanisms of these neuroprotective strategies are identified, their role in the distinct phases will provide further avenues to improve patient outcomes of AIS.

From Tumor Metastasis towards Cerebral Ischemia-Extracellular Vesicles as a General Concept of Intercellular Communication Processes

Extracellular vesicles (EVs) have been tremendous carriers in both experimental and translational science. These vesicles—formerly regarded as artifacts of in vitro research—have a heterogeneous population of vesicles derived from virtually all eukaryotic cells. EVs consist of a bilayer lipid structure with a diameter of about 30 to 1000 nm and have a characteristic protein and non-coding RNA content that make up different forms of EVs such as exosomes, microvesicles, and others. Despite recent progress in the EV field, which is known to serve as potential biomarkers and therapeutic tools under various pathological conditions, fundamental questions are yet to be answered. This short review focuses on recently reported data regarding EVs under pathological conditions with a particular emphasis on the role of EVs under such different conditions like tumor formation and cerebral ischemia. The review strives to point out general concepts of EV intercellular communication processes that might be vital to both diagnostic and therapeutic strategies in the long run.

PERSPECTIVES: Stroke survivors' views on the design of an early-phase cell therapy trial for patients with chronic ischaemic stroke

BACKGROUND

Stem cell research holds the potential for a paradigm shift in the management of diseases such as stroke. Patient and public involvement in research (PPIR) can bring a focus to issues of clinical relevance and accelerate translation to real-world clinical practice.

OBJECTIVE

A qualitative thematic analysis of the perspectives of stroke survivors regarding the conduct and design aspects of a proposed phase I clinical cell therapy study in stroke.

DESIGN

Twelve stroke survivors were purposively recruited in July 2016-August 2017 and participated in semi-structured, face-to-face interviews for input into the design of a proposed phase I clinical study of autologous dental pulp stem cells. Concurrent thematic analysis was conducted until data saturation was achieved.

DISCUSSION AND CONCLUSIONS

Participants conveyed that the most relevant outcomes to them were regaining participation, decreased dependence on caregivers and improvement in cognition, memory, mood, pain and fatigue. The perception of risk vs. benefit was likely influenced by the time elapsed since stroke, with participants being more willing to accept a higher level of risk early in the post-stroke disease course. They believed that all stroke survivors should be given an opportunity to participate in research, irrespective of their cognitive capacity. A relatively small sample population of 12 stroke survivors was studied as thematic saturation was achieved. PERSPECTIVES study applied principles of PPIR to early-phase cell research. Incorporation of outcomes relevant to patients' need within the study design is critical to generate data that will enable personalized application of regenerative medicine in stroke.

Conductive polymers to modulate the post-stroke neural environment

Despite the prevalence of stroke, therapies to augment recovery remain limited. Here we focus on the use of conductive polymers for cell delivery, drug release, and electrical stimulation to optimize the post-stroke environment for neural recovery. Conductive polymers and their interactions with in vitro and in vivo neural systems are explored. The ability to continuously modify the neural environment utilizing conductive polymers provides applications in directing stem cell differentiation and increasing neural repair. This exciting class of polymers offers new approaches to optimizing the post-stroke brain to improve functional recovery.

Anesthetic management of endovascular treatment for acute ischemic stroke: Influences on outcome and complications

Background and objectives

The emerging use of endovascular therapies for acute ischemic stroke, like intra-arterial thrombectomy, compels a better understanding of the anesthetic management required and its impact in global outcomes. This article reviews the available data on the anesthetic management of endovascular treatment, comparing general anesthesia with conscious sedation, the most used modalities, in terms of anesthetic induction and procedure duration, patient mobility, occlusion location, hemodynamic parameters, outcome and safety; it also focuses on the state-of-the-art on physiologic and pharmacologic neuroprotection.

Contents

Most of the evidence on this topic is retrospective and contradictory, with only three small randomized studies to date. Conscious sedation was frequently associated with better outcomes, but the prospective evidence declared that it has no advantage over general anesthesia concerning that issue. Conscious sedation is at least as safe as general anesthesia for the endovascular treatment of acute ischemic stroke, with equivalent mortality and fewer complications like pneumonia, hypotension or extubation difficulties. It has, however, a higher frequency of patient agitation and movement, which is the main cause for conversion to general anesthesia.

Conclusions

General anesthesia and conscious sedation are both safe alternatives for anesthetic management of patients submitted to endovascular thrombectomy. No anesthetic management is universally recommended and hopefully the ongoing randomized clinical trials will shed some light on the best approach; meanwhile, the choice of anesthesia should be based on the patient's individual characteristics. Regarding neuroprotection, hemodynamic stability is currently the most important strategy, as no pharmacological method has been proven effective in humans.

[Anesthetic management of endovascular treatment for acute ischemic stroke: Influences on outcome and complications]

BACKGROUND AND OBJECTIVES

The emerging use of endovascular therapies for acute ischemic stroke, like intra-arterial thrombectomy, compels a better understanding of the anesthetic management required and its impact in global outcomes. This article reviews the available data on the anesthetic management of endovascular treatment, comparing general anesthesia with conscious sedation, the most used modalities, in terms of anesthetic induction and procedure duration, patient mobility, occlusion location, hemodynamic parameters, outcome and safety; it also focuses on the state-of-the-art on physiologic and pharmacologic neuroprotection.

CONTENTS

Most of the evidence on this topic is retrospective and contradictory, with only three small randomized studies to date. Conscious sedation was frequently associated with better outcomes, but the prospective evidence declared that it has no advantage over general anesthesia concerning that issue. Conscious sedation is at least as safe as general anesthesia for the endovascular treatment of acute ischemic stroke, with equivalent mortality and fewer complications like pneumonia, hypotension or extubation difficulties. It has, however, a higher frequency of patient agitation and movement, which is the main cause for conversion to general anesthesia.

CONCLUSIONS

General anesthesia and conscious sedation are both safe alternatives for anesthetic management of patients submitted to endovascular thrombectomy. No anesthetic management is universally recommended and hopefully the ongoing randomized clinical trials will shed some light on the best approach; meanwhile, the choice of anesthesia should be based on the patient's individual characteristics. Regarding neuroprotection, hemodynamic stability is currently the most important strategy, as no pharmacological method has been proven effective in humans.

Xijiao Dihuang Decoction Alleviates Ischemic Brain Injury in MCAO Rats by Regulating Inflammation, Neurogenesis, and Angiogenesis

Ischemic stroke is an increasingly important public health problem, and no effective treatments are approved. Xijiao Dihuang Decoction (XDD), a famous herbal formula for treating hemorrhagic fever syndromes, has been shown to exert powerful neuroprotective property. The aim of this study was to identify the chemical constituents in XDD, observe the neuroprotective effect of XDD against acute ischemic stroke, and explore the specific mechanisms by which these effects were mediated. With UHPLC-Q/TOF-MS, 47 components in XDD were detected and 25 of them were identified. In rats subjected to MCAO, XDD ameliorated neurological deficit, histopathology changes, and infarction volume. In addition, levels of TNF-ɑ, IL-6, and IL-1β in XDD-treated group were significantly lower compared to the model group. Mechanistic studies showed that XDD inhibited MCAO-induced NF-κB activation, presenting as downregulating the expression of phospho-NF-κB p65 and preventing IκBɑ degradation. Besides, BDNF, GDNF, VEGF, bFGF, and CD34 levels were significantly increased by XDD, suggesting that the protective effects of XDD may also be associated with the promotion of neurogenesis and angiogenesis. In conclusion, these findings provided a novel regulatory pathway of the neuroprotective effect of XDD that helped rehabilitate patients with stroke.

Targeting NMDA receptors in stroke: new hope in neuroprotection

NMDA (N-methyl-d-aspartate) receptors (NMDARs) play a central role in excitotoxic neuronal death caused by ischemic stroke, but NMDAR channel blockers have failed to be translated into clinical stroke treatments. However, recent research on NMDAR-associated signaling complexes has identified important death-signaling pathways linked to NMDARs. This led to the generation of inhibitors that inhibit these pathways downstream from the receptor without necessarily blocking NMDARs. This therapeutic approach may have fewer side effects and/or provide a wider therapeutic window for stroke as compared to the receptor antagonists. In this review, we highlight the key findings in the signaling cascades downstream of NMDARs and the novel promising therapeutics for ischemic stroke.

New roles of reactive astrocytes in the brain; an organizer of cerebral ischemia

The brain consists of neurons and much higher number of glial cells. They communicate each other, by which they control brain functions. The brain is highly vulnerable to several insults such as ischemia, but has a self-protective and self-repairing mechanisms against these. Ischemic tolerance or preconditioning is an endogenous neuroprotective phenomenon, where a mild non-lethal ischemic episode can induce resistance to a subsequent severe ischemic injury in the brain. Because of its neuroprotective effects against cerebral ischemia or stroke, ischemic tolerance has been widely studied. However, almost all studies have been performed from the viewpoint of neurons. Glial cells are structurally in close association with synapses. Recent studies have uncovered the active roles of astrocytes in modulating synaptic connectivity, such as synapse formation, elimination and maturation, during development or pathology. However, glia-mediated ischemic tolerance and/or neuronal repairing have received only limited attention. We and others have demonstrated that glial cells, especially astrocytes, play a pivotal role in regulation of induction of ischemic tolerance as well as repairing/remodeling of neuronal networks by phagocytosis. Here, we review our current understanding of (1) glial-mediated ischemic tolerance and (2) glia-mediated repairing/remodeling of the penumbra neuronal networks, and highlight their mechanisms as well as their potential benefits, problems, and therapeutic application.

Astrocytes and ischemic tolerance

A mild non-lethal ischemic episode can induce resistance to a subsequent severe ischemic injury in the brain. This phenomenon is termed ischemic tolerance or ischemic preconditioning, and is an endogenous mechanism that can provide robust neuroprotection. Because of its neuroprotective effects against cerebral ischemia or stroke, ischemic tolerance has been widely studied. However, almost all studies have been performed from the viewpoint of neurons. Accumulating evidence suggests that glial cells have various roles in regulation of brain function, including modulation of synaptic transmission, neuronal excitation, and neuronal structure. In addition, astrocytes are closely related to homeostasis, stability of brain function, and protection of neurons. However, glial cells have received only limited attention with regard to ischemic tolerance. Cross-ischemic preconditioning is a phenomenon whereby non-ischemic preconditioning such as mechanical, thermal, and chemical treatment can induce ischemic tolerance. Of these, chemical treatments that affect the immune system can strongly induce ischemic tolerance, suggesting that glial cells may have important roles in this process. Indeed, we and others have demonstrated that glial cells, especially astrocytes, play a pivotal role in the induction of ischemic tolerance. This glial-mediated ischemic tolerance provides a robust and long-lasting neuroprotection against ischemic injury. In this review, we discuss the mechanisms underlying glial-mediated ischemic tolerance, as well as its potential benefits, problems, and therapeutic application.

Can adjunctive therapies augment the efficacy of endovascular thrombolysis? A potential role for activated protein C

In the management of acute ischemic stroke, vessel recanalization correlates with functional status, mortality, cost, and other outcome measures. Thrombolysis with intravenous tissue plasminogen activator has many limitations that restrict its applicability, but recent advances in the development of mechanical thrombectomy devices as well as improved systems of stroke care have resulted in greater likelihood of vessel revascularization. Nonetheless, there remains substantial discrepancy between rates of recanalization and rates of favorable outcome. The poor neurological recovery among some stroke patients despite successful recanalization confirms the need for adjuvant pharmacological therapy for neuroprotection and/or neurorestoration. Prior clinical trials of such drugs may have failed due to the inability of the agent to access the ischemic tissue beyond the occluded artery. A protocol that couples revascularization with concurrent delivery of a neuroprotectant drug offers the potential to enhance the benefit of thrombolysis. Analogs of activated protein C (APC) exert pleiotropic anti-inflammatory, anti-apoptotic, antithrombotic, cytoprotective, and neuroregenerative effects in ischemic stroke and thus appear to be promising candidates for this novel approach. A multicenter, prospective, double-blinded, dose-escalation Phase 2 randomized clinical trial has enrolled 110 patients to assess the safety, pharmacokinetics, and efficacy of human recombinant 3K3A-APC following endovascular thrombolysis. This article is part of the Special Issue entitled 'Cerebral Ischemia'.

Safety and efficacy of Cerebrolysin in motor function recovery after stroke: a meta-analysis of the CARS trials

This meta-analysis combines the results of two identical stroke studies (CARS-1 and CARS-2) assessing efficacy of Cerebrolysin on motor recovery during early rehabilitation. Cerebrolysin is a parenterally administered neuropeptide preparation approved for the treatment of stroke. Both studies had a prospective, randomized, double-blind, placebo-controlled design. Treatment with 30 ml Cerebrolysin once daily for 3 weeks was started 24–72 h after stroke onset. In addition, patients participated in a standardized rehabilitation program for 21 days that was initiated within 72 h after stroke onset. For both studies, the original analysis data were used for meta-analysis (individual patient data analysis). The combination of these two studies by meta-analytic procedures was pre-planned, and the methods were pre-defined under blinded conditions. The nonparametric Mann-Whitney (MW) effect size of the two studies on the ARAT score on day 90 indicated superiority of Cerebrolysin compared with placebo (MW 0.62, P < 0.0001, Wei-Lachin pooling procedure, day 90, last observation carried forward; N = 442). Also, analysis of early benefit at day 14 and day 21 by means of the National Institutes of Health Stroke Scale, which is regarded as most sensitive to early improvements, showed statistical significance (MW 0.59, P < 0.002). The corresponding number-needed-to-treat (NNT) for clinically relevant changes in early NIHSS was 7.1 (95% CI: 4 to 22). Cerebrolysin had a beneficial effect on motor function and neurological status in early rehabilitation patients after acute ischemic stroke. Safety aspects were comparable to placebo, showing a favourable benefit/risk ratio.

Efficacy and Safety of Cerebrolysin for Acute Ischemic Stroke: A Meta-Analysis of Randomized Controlled Trials

Cerebrolysin was reported to be effective in the neurological improvement of patients with acute ischemic stroke (AIS) in experimental models, while data from clinical trials were inconsistent. We performed a meta-analysis to explore the efficacy and safety of cerebrolysin for AIS. PubMed, EMBASE, and Cochrane Library were searched for randomized controlled trials, which intervened within 72 hours after the stroke onset. We investigated the efficacy and safety outcomes, respectively. Risk ratios and mean differences were pooled with fixed-effects model or random-effects model. Seven studies were identified, involving 1779 patients with AIS. The summary results failed to demonstrate significant superiority of cerebrolysin in the assessment of efficacy outcomes of mRS and BI. Similarly, administration of cerebrolysin had neutral effects on safety outcomes compared with placebo, including mortality and SAE. However, the number of included studies was small, especially in the analysis of efficacy outcomes, which might cause publication bias and inaccurate between-studies variance in the meta-analysis. Conclusively, although it seemed to be safe, routine use of cerebrolysin to improve the long-term rehabilitation after stroke could not be supported by available evidence.

Targeting a Potassium Channel/Syntaxin Interaction Ameliorates Cell Death in Ischemic Stroke

The voltage-gated K⁺ channel Kv2.1 has been intimately linked with neuronal apoptosis. After ischemic, oxidative, or inflammatory insults, Kv2.1 mediates a pronounced, delayed enhancement of K⁺ efflux, generating an optimal intracellular environment for caspase and nuclease activity, key components of programmed cell death. This apoptosis-enabling mechanism is initiated via Zn²⁺-dependent dual phosphorylation of Kv2.1, increasing the interaction between the channel's intracellular C-terminus domain and the SNARE (soluble N-ethylmaleimide-sensitive factor activating protein receptor) protein syntaxin 1A. Subsequently, an upregulation of de novo channel insertion into the plasma membrane leads to the critical enhancement of K⁺ efflux in damaged neurons. Here, we investigated whether a strategy designed to interfere with the cell death-facilitating properties of Kv2.1, specifically its interaction with syntaxin 1A, could lead to neuroprotection following ischemic injury in vivo The minimal syntaxin 1A-binding sequence of Kv2.1 C terminus (C1aB) was first identified via a far-Western peptide screen and used to create a protherapeutic product by conjugating C1aB to a cell-penetrating domain. The resulting peptide (TAT-C1aB) suppressed enhanced whole-cell K⁺ currents produced by a mutated form of Kv2.1 mimicking apoptosis in a mammalian expression system, and protected cortical neurons from slow excitotoxic injury in vitro, without influencing NMDA-induced intracellular calcium responses. Importantly, intraperitoneal administration of TAT-C1aB in mice following transient middle cerebral artery occlusion significantly reduced ischemic stroke damage and improved neurological outcome. These results provide strong evidence that targeting the proapoptotic function of Kv2.1 is an effective and highly promising neuroprotective strategy.SIGNIFICANCE STATEMENT Kv2.1 is a critical regulator of apoptosis in central neurons. It has not been determined, however, whether the cell death-enabling function of this K⁺ channel can be selectively targeted to improve neuronal survival following injury in vivo The experiments presented here demonstrate that the cell death-specific role of Kv2.1 can be uniquely modulated to provide neuroprotection in an animal model of acute ischemic stroke. We thus reveal a novel therapeutic strategy for neurological disorders that are accompanied by Kv2.1-facilitated forms of cell death.

Vectorized nanodelivery systems for ischemic stroke: a concept and a need

Neurological diseases of diverse aetiologies have significant effects on the quality of life of patients. The limited self-repairing capacity of the brain is considered to be the origin of the irreversible and progressive nature of many neurological diseases. Therefore, neuroprotection is an important goal shared by many clinical neurologists and neuroscientists. In this review, we discuss the main obstacles that have prevented the implementation of experimental neuroprotective strategies in humans and propose alternative avenues for the use of neuroprotection as a feasible therapeutic approach. Special attention is devoted to nanotechnology, which is a new approach for developing highly specific and localized biomedical solutions for the study of the multiple mechanisms involved in stroke. Nanotechnology is contributing to personalized neuroprotection by allowing us to identify mechanisms, determine optimal therapeutic windows, and protect patients from brain damage. In summary, multiple aspects of these new players in biomedicine should be considered in future in vivo and in vitro studies with the aim of improving their applicability to clinical studies.

Computer modeling of ischemic stroke

The occlusion of a blood vessel in the brain causes an ischemic stroke. Current treatment relies restoration of blood flow within 3 hours. Substantial research has focused on neuroprotection to spare compromised neural tissue and extend the treatment time window. Despite success with animal models and extensive associated clinical testing, there are still no therapies of this kind. Ischemic stroke is fundamentally a multiscale phenomenon where a cascade of changes triggered by loss of blood flow involves processes at spatial scales from molecular to centimeters with damage occurring in milliseconds to days and recovery into years. Multiscale computational modeling is a technique to assist understanding of the many agents involved in these multitudinous interacting pathways to provide clues for in silico development of multi-target polypharmacy drug cocktails.

Neuroprotective effect of a novel Chinese herbal decoction on cultured neurons and cerebral ischemic rats

Background

Historically, traditional Chinese medicine has been widely used to treat stroke. Based on the theory of Chinese medicine and the modern pharmacological knowledge of herbal medicines, we have designed a neuroprotective formula called Post-Stroke Rehabilitation (PSR), comprising seven herbs – Astragalus membranaceus (Fisch.) Bunge, Salvia miltiorrhiza Bunge, Paeonia lactiflora Pall., Cassia obtusifolia L., Ligusticum chuanxiong Hort., Angelica sinensis (Oliv.) Diels, and Glycyrrhiza uralensis Fisch. We aim to examine the neuroprotective activity of PSR in vitro and in vivo, and to explore the underlying molecular mechanisms, to better understand its therapeutic effect and to further optimize its efficacy.

Methods

PSR extract or vehicle was applied to primary rat neurons to examine their survival effects against N-methyl-d-aspartate (NMDA)-elicited excitotoxicity. Whole-cell patch-clamp recording was conducted to examine the NMDA-induced current in the presence of PSR. ERK- and CREB-activation were revealed by western blot analysis. Furthermore, PSR was tested for CRE promoter activation in neurons transfected with a luciferase reporter. The protective effect of PSR was then studied in the rat middle cerebral artery occlusion (MCAO) model. MCAO rats were either treated with PSR extract or vehicle, and their neurobehavioral deficit and cerebral infarct were evaluated. Statistical differences were analyzed by ANOVA or t-test.

Results

PSR prominently reduced the death of cultured neurons caused by NMDA excitotoxicity in a dose-dependent manner, indicating its neuroprotective property. Furthermore, PSR significantly reduced NMDA-evoked current reversibly and activated phosphorylation of ERK and CREB with distinct time courses, with the latter’s kinetics slower. PSR also triggered CRE-promoter activity as revealed by the increased expression of luciferase reporter in transfected neurons. PSR effectively reduced cerebral infarct and deficit in neurological behavior in MCAO rats when PSR decoction was administered starting either 6 days before or 6 h after onset of ischemia.

Conclusions

PSR is neuroprotective both in vitro and in vivo – it protects cultured neurons against NMDA excitotoxicity, and effectively reduces ischemic injury and neurobehavioral deficit in MCAO rats in both the pre- and post-treatment regimens. The underlying neuroprotective mechanisms may involve inhibition of NMDA receptor current and activation of ERK and CREB. This study provides important preclinical data necessary for the further development of PSR for stroke treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1417-1) contains supplementary material, which is available to authorized users.

Human endothelial progenitor cells rescue cortical neurons from oxygen-glucose deprivation induced death

BACKGROUND AND AIM

Cerebral ischemia is characterized by both acute and delayed neuronal injuries. Neuro-protection is a major issue that should be properly addressed from a pharmacological point of view, and cell-based treatment approaches are of interest due to their potential pleiotropic effects. Endothelial progenitor cells have the advantage of being mobilized from the bone marrow into the circulation, but have been less studied than other stem cells, such as mesenchymal stem cells. Therefore, the comparison between human endothelial progenitor cells (hEPC) and human mesenchymal progenitor cells (hMSC) in terms of efficacy in rescuing neurons from cell death after transitory ischemia is the aim of the current study, in the effort to address further directions.

MATERIALS AND METHODS

In vitro model of oxygen-glucose deprivation (OGD) on a primary culture of rodent cortical neurons was set up with different durations of exposure: 1, 2 and 3hrs with assessment of neuron survival. The 2hrs OGD was chosen for the subsequent experiments. After 2hrs OGD neurons were either placed in indirect co-culture with hMSC or hEPC or cultured in hMSC or hEPC conditioned medium and cell viability was evaluated by MTT assay.

RESULTS

At day 2 after 2hrs OGD exposure, mean neuronal survival was 47.9±24.2%. In contrast, after treatment with hEPC and hMSC indirect co-culture was 74.1±27.3%; and 69.4±18.8%, respectively. In contrast, treatment with conditioned medium did not provide any advantage in terms of survival to OGD neurons

CONCLUSION

The study shows the efficacy of hEPC in indirect co-culture to rescue neurons from cell death after OGD, comparable to that of hMSC. hEPC deserve further studies given their potential interest for ischemia.

Neuroprotective Properties of a Macrolide Antibiotic in a Mouse Model of Middle Cerebral Artery Occlusion: Characterization of the Immunomodulatory Effects and Validation of the Efficacy of Intravenous Administration

Repurposing the macrolide antibiotic azithromycin has recently been suggested as a promising neuroprotective strategy for the acute treatment of ischemic stroke. Here, we aim at further characterizing the immunomodulatory properties of intraperitoneal (i.p.) administration of this drug and, more importantly, at assessing whether neuroprotection can also be achieved by the more clinically relevant intravenous (i.v.) route of administration in a mouse model of focal cerebral ischemia induced by transient (30-min) middle cerebral artery occlusion (MCAo). A single i.p. injection of azithromycin (150 mg/kg) upon reperfusion prevented ischemia-induced spleen contraction and increased the number of MAC-1-immunopositive microglia/macrophages in the ischemic hemisphere 48 h after the insult. This was paralleled by an elevation of alternatively activated phenotypes (i.e., Ym1-immunopositive M2-polarized cells) and by a reduced expression of the pro-inflammatory marker myeloperoxidase. More importantly, i.v. administration of azithromycin upon reperfusion reduced MCAo-induced infarct volume and cerebral edema to an extent comparable to that obtained via the i.p. route. Although the i.p. route is often used for research purposes, it is impractical in the clinical setting; however, i.v. administration can easily be used in ischemic stroke patients who usually have i.v. access already established on hospital admission. The neuroprotective efficacy of the clinically relevant i.v. administration of azithromycin, together with its beneficial immunomodulatory properties reported in mice subjected to transient MCAo, suggests that this macrolide antibiotic can be effectively repurposed for the acute treatment of ischemic stroke. To this end, further work is needed to validate the efficacy of azithromycin in the clinical setting.

Bioluminescence imaging of transplanted human endothelial colony-forming cells in an ischemic mouse model

Ischemic strokes are devastating events responsible for high mortality and morbidity worldwide each year. Endothelial colony-forming cell (ECFC) therapy holds promise for stroke treatment; however, grafted ECFCs need to be monitored better understand their biological behavior in vivo, so as to evaluate their safety and successful delivery. The objectives of this study are to visualize the fate of infused human cord blood derived ECFCs via bioluminescence imaging (BLI) in an ischemic stroke mouse model and to determine the therapeutic effects of ECFC transplantation. ECFCs derived from human umbilical cord blood were infected with lentivirus carrying enhanced green fluorescent protein (eGFP) and firefly luciferase (Luc2) double fusion reporter gene. Labeled ECFCs were grafted into a photothrombotic ischemic stroke mouse model via intra-arterial injection though the left cardiac ventricle. The homing of infused cells and functional recovery of stroke mice were evaluated using BLI, neurological scoring, and immunohistochemistry. Significantly, BLI signals were highest in the brain on day 1 and decreased steadily until day 14. GFP-positive cells were also found surrounding infarct border zones in brain sections using immunohistochemical staining, suggesting that ECFCs properly homed to the ischemic brain tissue. Using a modified neurological severity score assay and histological analysis of brain slices with CD31 immunostaining in brain tissue, double cortin analysis, and the TdT-mediated dUTP nick end labeling (TUNEL) assay, we demonstrated functional restoration, improved angiogenesis, neurogenesis, and decreased apoptosis in ischemic mice after ECFC infusion. Collectively, our data support that ECFCs may be a promising therapeutic agent for stroke.

Changing Management of Acute Ischaemic Stroke: the New Treatments and Emerging Role of Endovascular Therapy

OPINION STATEMENT

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment, and the last two decades have seen a rapid advancement in the medical and endovascular treatment of acute ischaemic stroke. Intravenous tissue plasminogen activator (tPA) was first introduced as a safe and effective thrombolytic agent followed by the introduction of newer thrombolytic agents as well as anticoagulant and antiplatelet agents, proposed as potentially safer drugs with more favourable interaction profiles. In addition to chemo-thrombolysis, other techniques including transcranial sonothrombolysis and microbubble cavitation have been introduced which are showing promising results, but await large-scale clinical trials. These developments in medical therapies which are undoubtedly of great importance due to their potential widespread and immediate availability are paralleled with gradual but steady improvements in endovascular recanalisation techniques which were initiated by the introduction of the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) and Penumbra systems. The introduction of the Solitaire device was a significant achievement in reliable and safe endovascular recanalisation and was followed by further innovative stent retrievers. Initial trials failed to show a solid benefit in endovascular intervention compared with IV-tPA alone. These counterintuitive results did not last long, however, when a series of very well-designed randomised controlled trials, pioneered by MR-CLEAN, EXTEND-IA and ESCAPE, emerged, confirming the well-believed daily anecdotal evidence. There have now been seven positive trials of endovascular treatment for acute ischaemic stroke. Now that level I evidence regarding the superiority of endovascular recanalisation is abundantly available, the clinical challenge is how to select patients suitable for intervention and to familiarise and educate stroke care providers with this recent development in stroke care. It is important for the interventional services to be provided only in comprehensive stroke centres and endovascular interventions attempted by experienced well-trained operators, at this stage as an adjunct to the established medical treatment of IV-tPA, if there are no contraindications.

Efficacy and safety comparison of DL-3-n-butylphthalide and Cerebrolysin: Effects on neurological and behavioral outcomes in acute ischemic stroke

Cerebrolysin and DL-3-n-butylphthalide (NBP) have each shown neuroprotective efficacy in preclinical models of acute ischemic stroke (AIS) and passed clinical trials as therapeutic drugs for AIS. The present study was a clinical trial to assess and compare the efficacy and safety of NBP and Cerebrolysin in the reduction of neurological and behavioral disability following AIS. A randomized, double-blind trial was conducted with enrolment of 60 patients within 12 h of AIS. In addition to routine treatment, patients were randomly assigned to receive a 10-day intravenous administration of NBP, Cerebrolysin or placebo. National Institutes of Health Stroke Scale (NIHSS) and Barthel Index (BI) scores were used to evaluate the efficacy of the treatment in the patients with AIS at 11 and 21 days after the initiation of therapy. Adverse events were also analyzed among the three groups. After 10 days of treatment with NBP or Cerebrolysin, the NIHSS and BI scores at day 21 showed statistical differences compared with those in the placebo group (P<0.05). The improvements of NIHSS and BI scores in the NBP and Cerebrolysin groups were higher than those in the placebo group at days 11 and 21 (P<0.05). A statistically significant difference in the improvement of 21-day NIHSS scores was observed between the two treatment groups (P<0.05). No significant difference was found among the three groups with regard to the rate of adverse events. Favorable outcomes and good safety were observed in the patients with moderate AIS treated with NBP or Cerebrolysin. The results indicate that NBP may be more effective than Cerebrolysin in improving short-term outcomes following AIS. This trial is registered at ClinicalTrials.gov with clinical trial identifier number NCT02149875.

Targeted activation of CREB in reactive astrocytes is neuroprotective in focal acute cortical injury

The clinical challenge in acute injury as in traumatic brain injury (TBI) is to halt the delayed neuronal loss that occurs hours and days after the insult. Here we report that the activation of CREB-dependent transcription in reactive astrocytes prevents secondary injury in cerebral cortex after experimental TBI. The study was performed in a novel bitransgenic mouse in which a constitutively active CREB, VP16-CREB, was targeted to astrocytes with the Tet-Off system. Using histochemistry, qPCR, and gene profiling we found less neuronal death and damage, reduced macrophage infiltration, preserved mitochondria, and rescued expression of genes related to mitochondrial metabolism in bitransgenic mice as compared to wild type littermates. Finally, with meta-analyses using publicly available databases we identified a core set of VP16-CREB candidate target genes that may account for the neuroprotective effect. Enhancing CREB activity in astrocytes thus emerges as a novel avenue in acute brain post-injury therapeutics.

Treatment of Edema Associated With Intracerebral Hemorrhage

OPINION STATEMENT

Cerebral edema (i.e., "brain swelling") is a common complication following intracerebral hemorrhage (ICH) and is associated with worse clinical outcomes. Perihematomal edema (PHE) accumulates during the first 72 h after hemorrhage, and during this period, patients are at risk of clinical deterioration due to the resulting tissue shifts and brain herniation. First-line medical therapies for patients symptomatic of PHE include osmotic agents, such as mannitol in low- or high-dose bolus form, or boluses of hypertonic saline (HTS) at varied concentrations with or without subsequent continuous infusion. Decompressive craniectomy may be required for symptomatic edema refractory to osmotherapy. Other strategies that reduce PHE such as hypothermia and minimally invasive surgery have shown promise in pilot studies and are currently being evaluated in larger clinical trials. Ongoing basic, translational, and clinical research seek to better elucidate the pathophysiology of PHE to identify novel strategies to prevent edema formation as a next major advance in the treatment of ICH.

Therapeutics targeting the inflammasome after central nervous system injury

Innate immunity is part of the early response of the body to deal with tissue damage and infections. Because of the early nature of the innate immune inflammatory response, this inflammatory reaction represents an attractive option as a therapeutic target. The inflammasome is a component of the innate immune response involved in the activation of caspase 1 and the processing of pro-interleukin 1β. In this article, we discuss the therapeutic potential of the inflammasome after central nervous system (CNS) injury and stroke, as well as the basic knowledge we have gained so far regarding inflammasome activation in the CNS. In addition, we discuss some of the therapies available or under investigation for the treatment of brain injury, spinal cord injury, and stroke.

Argon Mediates Anti-Apoptotic Signaling and Neuroprotection via Inhibition of Toll-Like Receptor 2 and 4

Purpose

Recently, the noble gas argon attracted significant attention due to its neuroprotective properties. However, the underlying molecular mechanism is still poorly understood. There is growing evidence that the extracellular regulated kinase 1/2 (ERK1/2) is involved in Argon´s protective effect. We hypothesized that argon mediates its protective effects via the upstream located toll-like receptors (TLRs) 2 and 4.

Methods

Apoptosis in a human neuroblastoma cell line (SH-SY5Y) was induced using rotenone. Argon treatment was performed after induction of apoptosis with different concentrations (25, 50 and 75 Vol% in oxygen 21 Vol%, carbon dioxide and nitrogen) for 2 or 4 hours respectively. Apoptosis was analyzed using flow cytometry (annexin-V (AV)/propidiumiodide (PI)) staining, caspase-3 activity and caspase cleavage. TLR density on the cells’ surface was analyzed using FACS and immunohistochemistry. Inhibition of TLR signaling and extracellular regulated kinase 1/2 (ERK1/2) were assessed by western blot, activity assays and FACS analysis.

Results

Argon 75 Vol% treatment abolished rotenone-induced apoptosis. This effect was attenuated dose- and time-dependently. Argon treatment was accompanied with a significant reduction of TLR2 and TLR4 receptor density and protein expression. Moreover, argon mediated increase in ERK1/2 phosphorylation was attenuated after inhibition of TLR signaling. ERK1/2 and TLR signaling inhibitors abolished the anti-apoptotic and cytoprotective effects of argon. Immunohistochemistry results strengthened these findings.

Conclusion

These findings suggest that argon-mediated anti-apoptotic and neuroprotective effects are mediated via inhibition of TLR2 and TLR4.

Cerebrolysin and Recovery After Stroke (CARS): A Randomized, Placebo-Controlled, Double-Blind, Multicenter Trial

Supplemental Digital Content is available in the text.

The aim of this trial was to investigate whether stroke patients who receive Cerebrolysin show improved motor function in the upper extremities at day 90 compared with patients who receive a placebo.

Active Compounds of Rhubarb Root and Rhizome in Animal Model Experiments of Focal Cerebral Ischemia

Rhubarb root and rhizome (RRR) has been clinically used for stroke at least 2000 years and is still used in modern times in both China and elsewhere worldwide. The objective of present study was to evaluate the efficacy of active compounds of RRR (ACRRR) for experimental ischemic stroke. Studies of ACRRR in animal models of ischemic stroke were identified from 5 databases until April 2014. Study quality for each included article was evaluated according to the CAMARADES 10-item checklist. Outcome measures were neurological deficit score and infarct size. All the data were analyzed using RevMan 5.1 software. As a result, 20 studies were identified describing procedures involving 577 animals. The quality score of studies ranges from 2 to 6, and the median was 3.4. Six studies showed significant effects of ACRRR for improving infarct size compared with model group (P < 0.01). Six studies indicated significant effects of ACRRR for improving the neurological deficit scores according to Zea longa criterion or eight-point criterion (P < 0.01). In conclusion, these findings demonstrated a possible efficacy of ACRRR that have potential neuroprotective effect for experimental ischemic stroke. However, these apparently positive findings should be interpreted with caution because of the methodological flaws.

Combined neurothrombectomy or thrombolysis with adjunctive delivery of 3K3A-activated protein C in acute ischemic stroke

In the treatment of acute ischemic stroke (AIS), vessel recanalization correlates with improved functional status and reduced mortality. Mechanical neurothrombectomy achieves a higher likelihood of revascularization than intravenous thrombolysis (IVT), but there remains significant discrepancy between rates of recanalization and rates of favorable outcome. The poor neurological recovery among some stroke patients despite successful recanalization confirms the need for adjuvant therapy, such as pharmacological neuroprotection. Prior clinical trials of neuroprotectant drugs failed perhaps due to inability of the agent to reach the ischemic tissue beyond the occluded artery. A protocol that couples mechanical neurothrombectomy with concurrent delivery of a neuroprotectant overcomes this pitfall. Activated protein C (APC) exerts pleiotropic anti-inflammatory, anti-apoptotic, antithrombotic, cytoprotective, and neuroregenerative effects in stroke and appears a compelling candidate for this novel approach.

A combined pre-clinical meta-analysis and randomized confirmatory trial approach to improve data validity for therapeutic target validation

Biomedical research suffers from a dramatically poor translational success. For example, in ischemic stroke, a condition with a high medical need, over a thousand experimental drug targets were unsuccessful. Here, we adopt methods from clinical research for a late-stage pre-clinical meta-analysis (MA) and randomized confirmatory trial (pRCT) approach. A profound body of literature suggests NOX2 to be a major therapeutic target in stroke. Systematic review and MA of all available NOX2(-/y) studies revealed a positive publication bias and lack of statistical power to detect a relevant reduction in infarct size. A fully powered multi-center pRCT rejects NOX2 as a target to improve neurofunctional outcomes or achieve a translationally relevant infarct size reduction. Thus stringent statistical thresholds, reporting negative data and a MA-pRCT approach can ensure biomedical data validity and overcome risks of bias.

Neuroprotective therapies: Preclinical reproducibility is only part of the problem

Among the many unknowns in the translational path to developing drugs for acute stroke, addressing the reproducibility of preclinical data is only one piece of a multifaceted and incomplete puzzle (Llovera et al., this issue).

The value of patient selection in demonstrating treatment effect in stroke recovery trials: lessons from the CHIMES study of MLC601 (NeuroAiD)

OBJECTIVE

The CHIMES Study compared MLC601 to placebo in patients with ischemic stroke of intermediate severity in the preceding 72 hours. We aimed to verify if patient selection based on two prognostic factors (ie, stroke severity and time to treatment) improves detection of a treatment effect with MLC601.

METHODS

Analyses were performed using data from the CHIMES Study, an international, randomized, placebo-controlled, double-blind trial comparing MLC601 to placebo in patients with ischemic stroke of intermediate severity in the preceding 72 hours. Three subgroups, that is, onset to treatment time (OTT) ≥48 hours; baseline National Institute of Health Stroke Scale (NIHSS) ≥10; both OTT ≥48 hours and baseline NIHSS ≥10, were analyzed using modified Rankin Scale (mRS) ≤1 and a composite endpoint of mRS ≤1, Barthel Index ≥95, and NIHSS ≤1 at month 3.

RESULTS

Placebo response rates were lower (ie, worse natural outcome) among subgroups with prognostic factors. Conversely, MLC601 treatment effects were significantly higher in the subgroups with prognostic factors than for the entire cohort, being highest among patients with both OTT ≥48 hours and baseline NIHSS of 10 to 14: odds ratios of 2.18 (95% CI 1.02 to 4.65) for month 3 mRS ≤1 and 3.88 (95% CI 1.03 to 14.71) for the composite endpoint.

CONCLUSIONS

Patients who have moderately severe strokes and longer OTT demonstrate better treatment effects with MLC601. These factors can guide patient selection in future trials.

Human Urinary Kallidinogenase Promotes Angiogenesis and Cerebral Perfusion in Experimental Stroke

Angiogenesisis a key restorative mechanism in response to ischemia, and pro-angiogenic therapy could be beneficial in stroke. Accumulating experimental and clinical evidence suggest that human urinary kallidinogenase (HUK) improves stroke outcome, but the underlying mechanisms are not clear. The aim of current study was to verify roles of HUK in post-ischemic angiogenesis and identify relevant mediators. In rat middle cerebral artery occlusion (MCAO) model, we confirmed that HUK treatment could improve stroke outcome, indicated by reduced infarct size and improved neurological function. Notably, the ¹⁸F-FDG micro-PET scan indicated that HUK enhanced cerebral perfusion in rats after MCAO treatment. In addition, HUK promotespost-ischemic angiogenesis, with increased vessel density as well as up-regulated VEGF andapelin/APJ expression in HUK-treated MCAO mice. In endothelial cell cultures, induction of VEGF and apelin/APJ expression, and ERK1/2 phosphorylation by HUK was further confirmed. These changes were abrogated by U0126, a selective ERK1/2 inhibitor. Moreover, F13A, a competitive antagonist of APJ receptor, significantly suppressed HUK-induced VEGF expression. Furthermore, angiogenic functions of HUK were inhibited in the presence of selective bradykinin B1 or B2 receptor antagonist both in vitro and in vivo. Our findings indicate that HUK treatment promotes post-ischemic angiogenesis and cerebral perfusion via activation of bradykinin B1 and B2 receptors, which is potentially due to enhancement expression of VEGF and apelin/APJ in ERK1/2 dependent way.

Deciphering the pharmacological mechanism of the Chinese formula huanglian-jie-du decoction in the treatment of ischemic stroke using a systems biology-based strategy

AIM

Huanglian-jie-du decoction (HLJDD) is an important multiherb remedy in TCM, which is recently demonstrated to be effective to treat ischemic stroke. Here, we aimed to investigate the pharmacological mechanisms of HLJDD in the treatment of ischemic stroke using systems biology approaches.

METHODS

Putative targets of HLJDD were predicted using MetaDrug. An interaction network of putative HLJDD targets and known therapeutic targets for the treatment of ischemic stroke was then constructed, and candidate HLJDD targets were identified by calculating topological features, including 'Degree', 'Node-betweenness', 'Closeness', and 'K-coreness'. The binding efficiencies of the candidate HLJDD targets with the corresponding compositive compounds were further validated by a molecular docking simulation.

RESULTS

A total of 809 putative targets were obtained for 168 compositive compounds in HLJDD. Additionally, 39 putative targets were common to all four herbs of HLJDD. Next, 49 major nodes were identified as candidate HLJDD targets due to their network topological importance. The enrichment analysis based on the Gene Ontology (GO) annotation system and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway demonstrated that candidate HLJDD targets were more frequently involved in G-protein-coupled receptor signaling pathways, neuroactive ligand-receptor interactions and gap junctions, which all played important roles in the progression of ischemic stroke. Finally, the molecular docking simulation showed that 170 pairs of chemical components and candidate HLJDD targets had strong binding efficiencies.

CONCLUSION

This study has developed for the first time a comprehensive systems approach integrating drug target prediction, network analysis and molecular docking simulation to reveal the relationships between the herbs contained in HLJDD and their putative targets and ischemic stroke-related pathways.

Guidelines for the Management of Spontaneous Intracerebral Hemorrhage: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of spontaneous intracerebral hemorrhage.

METHODS

A formal literature search of PubMed was performed through the end of August 2013. The writing committee met by teleconference to discuss narrative text and recommendations. Recommendations follow the American Heart Association/American Stroke Association methods of classifying the level of certainty of the treatment effect and the class of evidence. Prerelease review of the draft guideline was performed by 6 expert peer reviewers and by the members of the Stroke Council Scientific Oversight Committee and Stroke Council Leadership Committee.

RESULTS

Evidence-based guidelines are presented for the care of patients with acute intracerebral hemorrhage. Topics focused on diagnosis, management of coagulopathy and blood pressure, prevention and control of secondary brain injury and intracranial pressure, the role of surgery, outcome prediction, rehabilitation, secondary prevention, and future considerations. Results of new phase 3 trials were incorporated.

CONCLUSIONS

Intracerebral hemorrhage remains a serious condition for which early aggressive care is warranted. These guidelines provide a framework for goal-directed treatment of the patient with intracerebral hemorrhage.