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

Comparative Analysis of the Results of Stroke Treatment With Multiple Administrations of Wharton's Jelly Mesenchymal Stem Cells-Derived HE-ATMP and Standard Conservative Treatment: Case Series Study

Stroke remains still the leading cause of long-term disability worldwide. Although interventions such as early reperfusion, intravenous thrombolysis, and endovascular revascularization have shown neurological benefit in stroke patients, there is still lack of effective treatment enabling regeneration of nervous tissue after cerebral ischemic episodes. Cell therapy is an evolving opportunity for stroke survivors with residual neurological deficits. The purpose of this study was to evaluate safety and potential efficacy of multiple administration of Hospital Exemption-Advanced Therapy Medicinal Product (HE-ATMP) comprising 3 × 107 Wharton's jelly mesenchymal stem cells (WJMSCs). A study group was composed of six patients-three women and three men. The patients were qualified to the treatment with diagnosis of chronic stroke (2-24 months after cerebral ischemic episode), during 2 years. All the patients undergone repeated rounds of HE-ATMP administration to the CSF (cerebrospinal fluid) via lumbar puncture. The control group consisted of six patients (two women and four men) who experienced stroke, treated at the same time (follow-up period: 24 months) using standard treatment methods, without endovascular treatment. To evaluate the results of the therapy, we used both impairment scales [National Institutes of Health Stroke Score (NIHSS)] and functional outcomes scales [Modified Rankin Scale (MRS) and Barthel Index (BI)]. In four patients, who received at least three repeated rounds of HE-ATMP, we reported neurological improvement and reduction of functional neurodeficiency. The biggest improvement concerned the reduction of speech disorders in two cases; significant improvement in the field of motor skills in three patients and reduction of apraxia and improvement of logical communication skills in two patients were also reported. All the patients became more independent. Significant improvement of the neurological condition using the same scales was registered only in two patients from the control group. We did not report any adverse events in the treated group during follow-up. At 1-year follow-up, we demonstrate safety and beneficial effect of WJMSC transplantation including neurological improvement and reduction of functional neurodeficiency. We are aware that the samples size of this study is relatively small. The treatment regimen needs to be further tested in larger group of patients.

Clinical Experience of Using an 8 French Newton Shaped Catheter (Neuro-EBU) During Endovascular Treatment: A Case Series of 21 Patients

The first step in endovascular treatment is the stable placement of a guide catheter (GC) into the target parent vessel. However, sufficient GC stabilization is sometimes difficult to obtain when the approach route has severe tortuosity. Here, we report our experience with and the usefulness of the 8 French (Fr) Newton-shaped Neuro-EBU vascular catheter (SILUX Co., Ltd., Kawaguchi City, Saitama Prefecture, Japan), which is rigid over its entire length except near the tip, in a case series of 21 patients. Of the 21 cases, 19 cases were successfully treated using the Neuro-EBU.

The 8 Fr Newton-shaped Neuro-EBU might be useful both as a special GC and as a wire exchange catheter when placement of the conventional GC is difficult due to severe tortuosity of the access route. Although rarely used, the Neuro-EBU catheter can serve as a practical alternative when the access route is challenging. To the best of our knowledge, there are no detailed reports on the technical use of the Newton-shaped vascular catheter in the field of neurointervention. We present the usefulness of the specially shaped 8 Fr guide catheter.

An Overview of Mesenchymal Stem Cell-based Therapy Mediated by Noncoding RNAs in the Treatment of Neurodegenerative Diseases

Mesenchymal stem cells (MSCs) have become a promising tool for neurorestorative therapy of neurodegenerative diseases (NDDs), which are mainly characterized by the progressive and irreversible loss of neuronal structure and function in the central or peripheral nervous system. Recently, studies have reported that genetic manipulation mediated by noncoding RNAs (ncRNAs) can increase survival and neural regeneration of transplanted MSCs, offering a new strategy for clinical translation. In this review, we summarize the potential role and regulatory mechanism of two major types of ncRNAs, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), during the neurogenesis of MSCs with gene expression profile analyses. We also overview the realization of MSC-based therapy mediated by ncRNAs in the treatment of spinal cord injury, stroke, Alzheimer's disease and peripheral nerve injury. It is expected that ncRNAs will become promising therapeutic targets for NDD on stem cells, while the underlying mechanisms require further exploration.

Preventive Effect of Albumin Nano TPA Gene Plasmid Ultrasound Microbubble Carrier System on Thrombosis after Cardiac Valve Replacement

After cardiac valve replacement, most patients will have different degrees of thrombosis, different parts of the thrombus, and even more frequent occurrence of postoperative thrombosis; therefore, the prevention of postoperative thrombosis is particularly important. The purpose of this study was to investigate the preventive effect of albumin nano tPA gene plasmid ultrasound microbubble carrier system on thrombosis, especially in cardiac valve. The experimental control method was used. Firstly, 11 dogs meeting the experimental requirements were selected. Secondly, the data of albumin nanoparticles and microbubbles were analyzed. The average size of albumin particles was 132.0 nm, the average size of microbubbles was 3.1 ± 1.6 μm, and the zeta potential was 13.70 ± 1.95 MV. The concentration of microbubbles was 4.2 ± 1.3 × 10/ml. Finally, 11 dogs were divided into two groups. The experimental group was treated with albumin nanoparticles ultrasound microbubble, and the others were the control group. It was found that the levels of tPA and D-dimer in the experimental group were significantly increased and maintained at a high level at 1 week after operation, and the prothrombin time was detected and the international normalized ratio was calculated at the same time. No significant changes were found in the experimental group.

Review of external referrals to a regional stroke centre: it is not just about thrombectomy

AIMS

To determine the experience of a regional stroke referral centre of external referrals for endovascular thrombectomy (EVT) in patients with symptoms of acute ischaemic stroke (AIS) and large vessel occlusion (LVO).

MATERIALS AND METHODS

Data were collected prospectively over two 4-month periods (2017-2018) on consecutive external referrals for EVT. Baseline demographics, imaging findings, and key time parameters were recorded. Reasons for not transferring patients and for not performing EVT were recorded. Key time intervals were calculated and compared between the transferred and non-transferred group with and without intracranial occlusion and between the transferred patients who underwent thrombectomy and those who did not.

RESULTS

Two hundred and sixty-two patients were referred. Sixty-one percent (n=159) were accepted and transferred for treatment. Of those transferred, 86% (n=136) had EVT. Fourteen percent (n=23) were unsuitable for EVT on arrival due to no vessel occlusion (48% n=11), poor Alberta Stroke Program Early CT Score (ASPECTS)/established infarct (30%, n=7) haemorrhage (9%, n=2), and clinical recovery (13% n=3). One hundred and three patients (39%) were ineligible for EVT following phone discussion due to absence of intracranial occlusion (59%, n=61), low ASPECTS (22%, n=23), distal occlusion (4%, n=4), low/improving National Institutes of Health Stroke Scale (NIHSS; 10.7%, n=11), and poor modified Rankin Scale (mRS) at baseline (3%, n=3). Patients with LVO but not transferred had longer onset to hospital arrival time compared with those transferred 151.5 versus 91 minutes (p<0.005), with a trend also toward a longer door to CT/CTA 40 minutes versus 30 minutes (p=0.142).

CONCLUSION

These data provide valuable insights into the service provision of a comprehensive stroke network. The present rates of EVT and futile transfers are modest compared to published data. Access to neuroradiology and specialised stroke assessment is crucial to optimise time to treatment.

Systems Pharmacology-Based Approach to Comparatively Study the Independent and Synergistic Mechanisms of Danhong Injection and Naoxintong Capsule in Ischemic Stroke Treatment

To provide evidence for the better clinical use of traditional Chinese medicine preparations (TCMPs), comparison of the pharmacological mechanisms between TCMPs with similar therapeutic effect is necessary. However, methodology for dealing with this issue is still scarce. Danhong injection (DHI) and Naoxintong capsule (NXT) are representative TCMPs for ischemic stroke (IS) treatment, which are also frequently used in combination. Here they were employed as research objects to demonstrate the feasibility of systems pharmacology approach in elucidation of the independent and combined effect of TCMPs. By incorporating chemical screening, target prediction, and network construction, a feasible systems pharmacology model has been established to systematically uncover the underlying action mechanisms of DHI, NXT, or their pair in IS treatment. Systematic analysis of the created TCMP-Compound-Target-Disease network revealed that DHI and NXT shared common targets such as PTGS2, F2, ADRB1, IL6, ALDH2, and CCL2, which were involved in the vasomotor system regulation, blood-brain barrier disruption, redox imbalance, neurotrophin activity, and brain inflammation. In comparative mechanism study, the merged DHI/NXT-IS PPI network and pathway enrichment analysis indicated that DHI and NXT exerted the therapeutic effects mainly through immune system and VEGF signaling pathways. Meanwhile, they had their own unique pathways, e.g., calcium signaling pathway for DHI and gap junction for NXT. While for their synergistic mechanism, DHI and NXT participated in chemokine signaling pathway, T cell receptor signaling pathway, VEGF signaling pathway, gap junction, and so on. Our study provided an optimized strategy for dissecting the different and combined effect of TCMPs with similar actions.

[Cell therapy for ischemic stroke. Stem cell types and results of pre-clinical trials]

The literature review addresses the use of stem cells (SC) in ischemic stroke (IS). Part 1 of the paper overviews the results of experimental animal studies. Characteristics of different SC types and results of their studies in experimental models of IS are presented in the first section, the second section considers pros and cons of the methods of SC injection.

Mesenchymal Stem Cell Therapy in Stroke: A Systematic Review of Literature in Pre-Clinical and Clinical Research

Exogenous stem cell therapy (SCT) has been recognized recently as a promising neuroregenerative strategy to augment recovery in stroke survivors. Mesenchymal stem cells (MSCs) are the primary source of stem cells used in the majority of both pre-clinical and clinical studies in stroke. In the absence of evidence-based guidelines on the use of SCT in stroke patients, understanding the progress of MSC research across published studies will assist researchers and clinicians in better achieving success in translating research. We conducted a systematic review on published literature using MSCs in both pre-clinical studies and clinical trials between 2008 and 2017 using the public databases PubMed and Ovid Medline, and the clinical trial registry ( www.clinicaltrials.gov ). A total of 78 pre-clinical studies and eight clinical studies were identified. While majority of the pre-clinical and clinical studies demonstrated statistically significant effects, the clinical significance of these findings was still unclear. Effect sizes could not be measured mainly due to reporting issues in pre-clinical studies, thus limiting our ability to compare results across studies quantitatively. The overall quality of both pre-clinical and clinical studies was sub-optimal. By conducting a systematic review of both pre-clinical and clinical studies on MSCs therapy in stroke, we assessed the quality of current evidence and identified several issues and gaps in translating animal studies to human trials. Addressing these issues and incorporating changes into future animal studies and human trials may lead to better success of stem cells-based therapeutics in the near future.

Neuro-Interventional Management of Acute Ischemic Stroke

Restoration of cerebral blood flow is the most important step in preventing irreversible damage to hypoperfused brain cells after ischemic stroke from large-vessel occlusion. For those patients who do not respond to (or are not eligible for) intravenous thrombolysis, endovascular therapy has become standard of care. A shift is currently taking place from rigid time windows for intervention (time is brain) to physiology-driven paradigms that rely heavily on neuroimaging. At this time, one can reasonably anticipate that more patients will be treated, and that outcomes will keep improving. This article discusses in detail recent advances in endovascular stroke therapy.

Quantitative sodium MR imaging: A review of its evolving role in medicine

Sodium magnetic resonance (MR) imaging in humans has promised metabolic information that can improve medical management in important diseases. This technology has yet to find a role in clinical practice, lagging proton MR imaging by decades. This review covers the literature that demonstrates that this delay is explained by initial challenges of low sensitivity at low magnetic fields and the limited performance of gradients and electronics available in the 1980s. These constraints were removed by the introduction of 3T and now ultrahigh (≥7T) magnetic field scanners with superior gradients and electronics for proton MR imaging. New projection pulse sequence designs have greatly improved sodium acquisition efficiency. The increased field strength has provided the expected increased sensitivity to achieve resolutions acceptable for metabolic interpretation even in small target tissues. Consistency of quantification of the sodium MR image to provide metabolic parametric maps has been demonstrated by several different pulse sequences and calibration procedures. The vital roles of sodium ion in membrane transport and the extracellular matrix will be reviewed to indicate the broad opportunities that now exist for clinical sodium MR imaging. The final challenge is for the technology to be supplied on clinical ≥3T scanners.

Intravenous administration of xenogenic adipose-derived mesenchymal stem cells (ADMSC) and ADMSC-derived exosomes markedly reduced brain infarct volume and preserved neurological function in rat after acute ischemic stroke

We tested the hypothesis that combined xenogenic (from mini-pig) adipose-derived mesenchymal stem cell (ADMSC) and ADMSC-derived exosome therapy could reduce brain-infarct zone (BIZ) and enhance neurological recovery in rat after acute ischemic stroke (AIS) induced by 50-min left middle cerebral artery occlusion. Adult-male Sprague-Dawley rats (n = 60) were divided equally into group 1 (sham-control), group 2 (AIS), group 3 [AIS-ADMSC (1.2×106 cells)], group 4 [AIS-exosome (100μg)], and group 5 (AIS-exosome-ADMSC). All therapies were provided intravenously at 3h after AIS procedure. BIZ determined by histopathology (by day-60) and brain MRI (by day-28) were highest in group 2, lowest in group 1, higher in groups 3 and 4 than in group 5, but they showed no difference between groups 3 and 4 (all p < 0.0001). By day-28, sensorimotor functional results exhibited an opposite pattern to BIZ among the five groups (p < 0.005). Protein expressions of inflammatory (inducible nitric oxide synthase/tumor necrosis factor-α/nuclear factor-κB/interleukin-1β/matrix metalloproteinase-9/plasminogen activator inhibitor-1/RANTES), oxidative-stress (NOX-1/NOX-2/oxidized protein), apoptotic (caspase-3/ Poly-ADP-ribose polymerase), and fibrotic (Smad3/transforming growth factor-β) biomarkers, and cellular expressions of brain-damaged (γ-H2AX+/ XRCC1-CD90+/p53BP1-CD90+), inflammatory (CD11+/CD68+/glial fibrillary acid protein+) and brain-edema (aquaporin-4+) markers showed a similar pattern of BIZ among the groups (all n < 0.0001). In conclusion, xenogenic ADMSC/ADMSC-derived exosome therapy was safe and offered the additional benefit of reducing BIZ and improving neurological function in rat AIS.

Current evidence for endovascular therapy in stroke and remaining uncertainties

Class 1 level A evidence now supports endovascular thrombectomy as best practice in the management of large vessel occlusion acute ischaemic stroke. However, significant questions pertaining to initial imaging, radiological assessment, patient selection and therapeutic limits remain unanswered. A specific cohort of patients who benefit from endovascular thrombectomy has been established, although current uncertainties regarding selection of those not meeting top-tier evidence criteria may potentially deny certain patients the benefit of intervention. This is of particular relevance in patients presenting in a delayed manner. Whilst superior outcomes are achieved with reduced time to endovascular reperfusion, denying patients intervention based on symptom duration alone may not be appropriate. Advanced understanding of ischaemic stroke pathophysiology supports an individualized approach to patient evaluation, given variance in the rate of ischaemic core progression and the extent of salvageable penumbra. Physiological imaging techniques may therefore be utilized to better inform patient selection for endovascular thrombectomy and evidence suggests that a transition from time-based to tissue-based therapeutic thresholds may be of greater value. Multiple ongoing randomized controlled trials aim to further define the benefit of endovascular thrombectomy and it is hoped that these results will advance, and possibly broaden, patient selection criteria to ensure that maximum benefit from the intervention may be achieved.

Safety and effectiveness of stem cell therapies in early-phase clinical trials in stroke: a systematic review and meta-analysis

Stem cells have demonstrated encouraging potential as reparative therapy for patients suffering from post-stroke disability. Reperfusion interventions in the acute phase of stroke have shown significant benefit but are limited by a narrow window of opportunity in which they are beneficial. Thereafter, rehabilitation is the only intervention available. The current review summarises the current evidence for use of stem cell therapies in stroke from early-phase clinical trials. The safety and feasibility of administering different types of stem cell therapies in stroke seem to be reasonably proven. However, the effectiveness needs still to be established through bigger clinical trials with more pragmatic clinical trial designs that address the challenges raised by the heterogeneous nature of stroke per se, as well those due to unique characteristics of stem cells as therapeutic agents.

Proof of concept and feasibility studies examining the influence of combination ribose, adenine and allopurinol treatment on stroke outcome in the rat

Background

Cerebral ischaemia results in a rapid and profound depletion of adenosine triphosphate (ATP), the energy currency of the cell. This depletion leads to disruption of cellular homeostasis and cell death. Early replenishment of ATP levels might therefore have a neuroprotective effect in the injured brain. We have previously shown that the ATP precursors, D-ribose and adenine (RibAde), restored the reduced ATP levels in rat brain slices to values similar to those measured in the intact rodent brain. The aim of this study was to assess whether RibAde, either alone or in combination with the xanthine oxidase inhibitor allopurinol (RibAdeAll; to further increase the availability of ATP precursors), could improve outcome in an in vivo rodent model of transient cerebral ischaemia.

Methods

After 60 min occlusion of the middle cerebral artery, and upon reperfusion, rats were administered saline, RibAde, or RibAdeAll for 6 h. Baseline lesion volume was determined by diffusion-weighted MRI prior to reperfusion and final infarct volume determined by T2-weighted MRI at Day 7. Neurological function was assessed at Days 1, 3 and 7.

Results

Ischaemic lesion volume decreased between Days 1 and 7: a 50% reduction was observed for the RibAdeAll group, 38% for the RibAde group and 18% in the animals that received saline. Reductions in lesion size in treatment groups were accompanied by a trend for faster functional recovery.

Conclusion

These data support the potential use of ribose, adenine and allopurinol in the treatment of cerebral ischaemic injury, especially since all compounds have been used in man.

Current and future perspectives on the treatment of cerebral ischemia

INTRODUCTION

After heart disease and combined forms of cancer, stroke is the leading cause of death in the United States. Currently, tissue-plasminogen activator (tPA) thrombolysis is the only thrombolytic therapy that has been shown to improve patient outcome. Presently, the only antithrombotic drug treatment that has proven effective at improving acute ischemic stroke patient outcome is aspirin administration. Despite these studies, no clinical trials have yet demonstrated a reliably effective pharmacological treatment. Areas covered: We conducted a search of recent drug studies for ischemic stroke on clinicaltrials.gov in addition to a literature search for acute ischemic stroke therapy using PubMed. This review details our findings of recent advancements in the pharmacological treatment of acute ischemic stroke. Expert commentary: We concluded that recent attempts to establish new pharmacological treatment protocols for acute ischemic stroke have had limited success, but many Phase III and Phase IV clinical trials demonstrate promise. Moreover, several studies have demonstrated the efficacy of dual-antiplatelet therapies at reducing risk of secondary stroke. Studies for novel therapeutic targets for neuroprotection have been largely unsuccessful. Some trials had positive results; however, there is much room for improvement and other studies show promise in their preliminary stages.

Achieving Multidisciplinary Collaboration for the Creation of a Pulmonary Embolism Response Team: Creating a "Team of Rivals"

Pulmonary embolism response teams (PERTs) have recently been developed to streamline care for patients with life-threatening pulmonary embolism (PE). PERTs are unique among rapid response teams, in that they bring together a multidisciplinary team of specialists to care for a single disease for which there are novel treatments but few comparative data to guide treatment. The PERT model describes a process that includes activation of the team; real-time, multidisciplinary consultation; communication of treatment recommendations; mobilization of resources; and collection of research data. Interventional radiologists, along with cardiologists, emergency physicians, hematologists, pulmonary/critical care physicians, and surgeons, are core members of most PERTs. Bringing together such a wide array of experts leverages the expertise and strengths of each specialty. However, it can also lead to challenges that threaten team cohesion and cooperation. The purpose of this article is to discuss ways to integrate multiple specialists, with diverse perspectives and skills, into a cohesive PERT. The authors will discuss the purpose of forming a PERT, strengths of different PERT specialties, strategies to leverage these strengths to optimize participation and cooperation across team members, as well as unresolved challenges.

Theophylline as an add-on to thrombolytic therapy in acute ischaemic stroke (TEA-Stroke): A randomized, double-blinded, placebo-controlled, two-centre phase II study

Introduction

Early reperfusion of brain tissue at risk of injury (penumbra salvage) is crucial in treating acute ischaemic stroke. Neuroprotective agents may extend the time window for the reperfusion. The vasoactive agent theophylline redistributes the perfusion to ischaemic brain tissue and thus reduces brain damage, brain tissue oedema and mortality in animal stroke models. Furthermore, treatment with theophylline has been shown to result in considerable and rapid clinical improvement, albeit only temporary, in some stroke patients.We hypothesize that treatment with theophylline will improve the collateral supply in acute ischaemic brain tissue and thus facilitate reperfusion despite proximal vessel occlusion. The primary study objective is to evaluate whether theophylline is safe and efficient in acute ischaemic stroke patients as an add-on to thrombolytic therapy.

Methods

The TEA-Stroke Trial is a two-centre, proof of concept phase II clinical study with a randomized, double-blinded, placebo-controlled design. One hundred and twenty patients with acute ischaemic stroke and significant perfusion-diffusion mismatch, as determined by magnetic resonance imaging, are randomized 1:1 to either theophylline or placebo as an add-on to standard thrombolytic therapy.

Study outcome

The dual primary outcome measures include penumbra salvage (penumbral tissue not developing into infarcted tissue) and clinical improvement at the 24-h follow-up.

Discussion

Results from studies of theophylline in stroke animal models, clinical case series and randomized clinical trials are controversial. A Cochrane analysis from 2004 concluded that there was not enough evidence to assess whether theophylline is safe and improves outcomes in patients with acute ischaemic stroke. The TEA-Stroke Trial will clarify whether theophylline as an add-on to standard thrombolytic therapy improves penumbra salvage with a reduced risk of reperfusion damage, reduced final infarct size, and improved clinical outcome.