Remote Ischemic Conditioning for Acute Stroke: The RESIST Randomized Clinical Trial

Exosomes: the next-generation therapeutic platform for ischemic stroke

Current therapeutic strategies for ischemic stroke fall short of the desired objective of neurological functional recovery. Therefore, there is an urgent need to develop new methods for the treatment of this condition. Exosomes are natural cell-derived vesicles that mediate signal transduction between cells under physiological and pathological conditions. They have low immunogenicity, good stability, high delivery efficiency, and the ability to cross the blood-brain barrier. These physiological properties of exosomes have the potential to lead to new breakthroughs in the treatment of ischemic stroke. The rapid development of nanotechnology has advanced the application of engineered exosomes, which can effectively improve targeting ability, enhance therapeutic efficacy, and minimize the dosages needed. Advances in technology have also driven clinical translational research on exosomes. In this review, we describe the therapeutic effects of exosomes and their positive roles in current treatment strategies for ischemic stroke, including their anti-inflammation, anti-apoptosis, autophagy-regulation, angiogenesis, neurogenesis, and glial scar formation reduction effects. However, it is worth noting that, despite their significant therapeutic potential, there remains a dearth of standardized characterization methods and efficient isolation techniques capable of producing highly purified exosomes. Future optimization strategies should prioritize the exploration of suitable isolation techniques and the establishment of unified workflows to effectively harness exosomes for diagnostic or therapeutic applications in ischemic stroke. Ultimately, our review aims to summarize our understanding of exosome-based treatment prospects in ischemic stroke and foster innovative ideas for the development of exosome-based therapies.

Neuroprotection on ischemic brain injury by Mg2+/H2 released from endovascular Mg implant

Most acute ischemic stroke patients with large vessel occlusion require stent implantation for complete recanalization. Yet, due to ischemia-reperfusion injury, over half of these patients still experience poor prognoses. Thus, neuroprotective treatment is imperative to alleviate the ischemic brain injury, and a proof-of-concept study was conducted on "biodegradable neuroprotective stent". This concept is premised on the hypothesis that locally released Mg2+/H2 from Mg metal within the bloodstream could offer synergistic neuroprotection against reperfusion injury in distant cerebral ischemic tissues. Initially, the study evaluated pure Mg's neuroactive potential using oxygen-glucose deprivation/reoxygenation (OGD/R) injured neuron cells. Subsequently, a pure Mg wire was implanted into the common carotid artery of the transient middle cerebral artery occlusion (MCAO) rat model to simulate human brain ischemia/reperfusion injury. In vitro analyses revealed that pure Mg extract aided mouse hippocampal neuronal cell (HT-22) in defending against OGD/R injury. Additionally, the protective effects of the Mg wire on behavioral abnormalities, neural injury, blood-brain barrier disruption, and cerebral blood flow reduction in MCAO rats were verified. Conclusively, Mg-based biodegradable neuroprotective implants could serve as an effective local Mg2+/H2 delivery system for treating distant cerebral ischemic diseases.

Differential efficacy of remote ischaemic conditioning in anterior versus posterior circulation stroke: A prespecified secondary analysis of the RICAMIS trial

BACKGROUND AND PURPOSE

The benefit of remote ischaemic conditioning (RIC) in acute moderate ischaemic stroke has been demonstrated by the Remote Ischaemic Conditioning for Acute Moderate Ischaemic Stroke (RICAMIS) study. This prespecified exploratory analysis aimed to determine whether there was a difference of RIC efficacy in anterior versus posterior circulation stroke based on RICAMIS data.

METHODS

In this analysis, eligible patients presenting within 48 h of stroke onset were divided into two groups: anterior circulation stroke (ACS) and posterior circulation stroke (PCS) groups. The primary endpoint was an excellent functional outcome, defined as a modified Rankin Scale (mRS) score 0-1 at 90 days.

RESULTS

In all, 1013 patients were included in the final analysis, including 642 with ACS and 371 with PCS. Compared with the control group, RIC was significantly associated with an increased proportion of mRS scores 0-1 within 90 days in the PCS group (unadjusted odds ratio 1.6, 95% confidence interval 1.0-2.4, p = 0.04; adjusted odds ratio 2.0, 95% confidence interval 1.2-3.3, p = 0.005), but not in the ACS group (p = 0.29). Similar results were found regarding secondary outcomes including mRS score 0-2 at 90 days, mRS distribution at 90 days and change in National Institutes of Health Stroke Scale score at day 12 from baseline. However, there was no significant interaction effect between stroke location and intervention on the primary outcome (pinteraction = 0.21).

CONCLUSION

Amongst patients with acute PCS who are not candidates for reperfusion treatment, RIC may be associated with a higher probability of improved functional outcomes. These findings need to be validated in prospective trials.

Rationale and design of RESILIENCE: A prospective randomized clinical trial evaluating remote ischaemic conditioning for the prevention of anthracycline cardiotoxicity

AIMS

There is a lack of therapies able to prevent anthracycline cardiotoxicity (AC). Remote ischaemic conditioning (RIC) has shown beneficial effects in preclinical models of AC.

METHODS

REmote iSchemic condItioning in Lymphoma PatIents REceiving ANthraCyclinEs (RESILIENCE) is a multinational, prospective, phase II, double-blind, sham-controlled, randomized clinical trial that evaluates the efficacy and safety of RIC in lymphoma patients receiving anthracyclines. Patients scheduled to undergo ≥5 chemotherapy cycles including anthracyclines and with ≥1 AC-associated risk factors will be randomized to weekly RIC or sham throughout the chemotherapy period. Patients will undergo three multiparametric cardiac magnetic resonance (CMR) studies, at baseline, after the third cycle (intermediate CMR), and 2 months after the end of chemotherapy. Thereafter, patients will be followed up for clinical events over an anticipated median of ≥24 months. The primary endpoint is the absolute change from baseline in CMR-based left ventricular ejection fraction (LVEF). The main secondary outcome is the incidence of AC events, defined as (1) a drop in CMR-based LVEF of ≥10 absolute points, or (2) a drop in CMR-based LVEF of ≥5 and <10 absolute points to a value <50%. Intermediate CMR will test the ability of T2 mapping to predict AC versus classical markers (left ventricular strain and cardiac injury biomarkers). A novel CMR sequence allowing ultrafast cine acquisition will be validated in this vulnerable population.

CONCLUSIONS

The RESILIENCE trial will test RIC (a novel non-invasive intervention to prevent AC) in a cohort of high-risk patients. The trial will also test candidate markers for their capacity to predict AC and will validate a novel CMR sequence reducing acquisition time in a vulnerable population.

Comprehensive Management of Stroke: From Mechanisms to Therapeutic Approaches

Acute ischemic stroke (AIS) is a challenging disease, which needs urgent comprehensive management. Endovascular thrombectomy (EVT), alone or combined with iv thrombolysis, is currently the most effective therapy for patients with acute ischemic stroke (AIS). However, only a limited number of patients are eligible for this time-sensitive treatment. Even though there is still significant room for improvement in the management of this group of patients, up until now there have been no alternative therapies approved for use in clinical practice. However, there is still hope, as clinical research with novel emerging therapies is now generating promising results. These drugs happen to stop or palliate some of the underlying molecular mechanisms involved in cerebral ischemia and secondary brain damage. The aim of this review is to provide a deep understanding of these mechanisms and the pathogenesis of AIS. Later, we will discuss the potential therapies that have already demonstrated, in preclinical or clinical studies, to improve the outcomes of patients with AIS.

Remote Ischemic Conditioning With Medical Management or Reperfusion Therapy for Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Remote ischemic conditioning (RIC) is a low-cost, accessible, and noninvasive neuroprotective treatment strategy, but its efficacy and safety in acute ischemic stroke are controversial. With the publication of several randomized controlled trials (RCTs) and the recent results of the RESIST trial, it may be possible to identify the patient population that may (or may not) benefit from RIC. This systematic review and meta-analysis aims to evaluate the effectiveness and safety of RIC in patients with ischemic stroke receiving different treatments by pooling data of all randomized controlled studies to date.

METHODS

We searched the PubMed, Embase, Cochrane, Elsevier, and Web of Science databases to obtain articles in all languages from inception until May 25, 2023. The primary outcome was the modified Rankin Scale (mRS) score at the specified endpoint time in the trial. The secondary outcomes were change in NIH Stroke Scale (NIHSS) and recurrence of stroke events. The safety outcomes were cardiovascular events, cerebral hemorrhage, and mortality. The quality of articles was evaluated through the Cochrane risk assessment tool. This study was registered in PROSPERO (CRD42023430073).

RESULTS

There were 7,657 patients from 22 RCTs included. Compared with the control group, patients who received RIC did not have improved mRS functional outcomes, regardless of whether they received medical management, reperfusion therapy with intravenous thrombolysis (IVT), or mechanical thrombectomy (MT). In the medical management group, patients who received RIC had decreased incidence of stroke recurrence (risk ratio 0.63, 95% CI 0.43-0.92, p = 0.02) and lower follow-up NIHSS score by 1.72 points compared with the control group (p < 0.00001). There was no increased risk of adverse events including death or cerebral hemorrhage in the IVT or medical management group.

DISCUSSION

In patients with ischemic stroke who are not eligible for reperfusion therapy, RIC did not affect mRS functional outcomes but significantly improved the NIHSS score at the follow-up endpoint and reduced stroke recurrence, without increasing the risk of cerebral hemorrhage or death. In patients who received IVT or MT, the benefit of RIC was not observed.

Exploring vascular contributions to cognitive impairment and dementia (ENIGMA): protocol for a prospective observational study

BACKGROUND

Post-stroke cognitive impairment (PSCI) is common. However, the underlying pathophysiology remains largely unknown. Understanding the role of microvascular changes and finding markers that can predict PSCI, could be a first step towards better screening and management of PSCI. Capillary dysfunction is a pathological feature of cerebral small vessel disease and may play a role in the mechanisms underlying PSCI. Extracellular vesicles (EVs) are secreted from cells and may act as disease biomarkers. We aim to investigate the role of capillary dysfunction in PSCI and the associations between EV characteristics and cognitive function one year after acute ischemic stroke (AIS) and transient ischemic attack (TIA).

METHODS

The ENIGMA study is a single-centre prospective clinical observational study conducted at Aarhus University Hospital, Denmark. Consecutive patients with AIS and TIA are included and followed for one year with follow-up visits at three and 12 months. An MRI is performed at 24 h and 12 months follow-up. EV characteristics will be characterised from blood samples drawn at 24 h and three months follow-up. Cognitive function is assessed three and 12 months after AIS and TIA using the Repeatable Battery for the Assessment of Neuropsychological Status.

DISCUSSION

Using novel imaging and molecular biological techniques the ENIGMA study will provide new knowledge about the vascular contributions to cognitive decline and dementia.

TRIAL REGISTRATION

The study is retrospectively registered as an ongoing observational study at ClinicalTrials.gov with the identifier NCT06257823.

Duration of Remote Ischemic Conditioning and Outcome in Acute Ischemic Stroke

BACKGROUND

Remote ischemic conditioning has been found to be effective in improving functional outcomes in acute ischemic stroke. We conducted a post hoc analysis of the RICAMIS (Remote Ischemic Conditioning for Acute Moderate Ischemic Stroke) trial to determine whether long-term remote ischemic conditioning duration after stroke onset is associated with better clinical outcomes in ischemic stroke.

METHODS AND RESULTS

Patients from the full analysis set were included in this secondary analysis. The primary outcome was the proportion of patients with an excellent functional outcome at 90 days, defined as a modified Rankin Scale score of 0 to 1. Among the 1776 patients, there were 55 patients in the 1 to 7 days remote ischemic conditioning group, 345 in the 8 to 10 days group, 412 in the 11 to 13 days group, 51 in the 14 to 16 days group, and 913 in the control group. Compared with the control group, a significantly higher proportion of excellent functional outcomes at 90 days was found in the 11 to 13 days remote ischemic conditioning group (adjusted absolute difference, 9.1% [95% CI, 3.7%-14.5%]; P =0.001), which was attenuated in the other groups (adjusted absolute difference in the 8-10 days group, 2.0% [95% CI, -4.0% to 8.0%]; P=0.51; adjusted absolute difference in the 14-16 days group, 7.4% [95% CI, -5.8% to 20.5%]; P=0.27), but compared to the control group, there was lower proportion of excellent functional outcomes in the 1 to 7 days group (adjusted absolute difference, -14.4% [95% CI, -27.8% to 0.0%]; P=0.05).

CONCLUSIONS

Among patients with acute moderate ischemic stroke, a higher likelihood of excellent clinical outcome was found in patients with longer duration of remote ischemic conditioning.

Effect of Remote Ischemic Conditioning in Ischemic Stroke Subtypes: A Post Hoc Subgroup Analysis From the RESIST Trial

BACKGROUND

Remote ischemic conditioning (RIC) is a simple and noninvasive procedure that has proved to be safe and feasible in numerous smaller clinical trials. Mixed results have been found in recent large randomized controlled trials. This is a post hoc subgroup analysis of the RESIST trial (Remote Ischemic Conditioning in Patients With Acute Stroke), investigating the effect of RIC in different acute ischemic stroke etiologies, and whether an effect was modified by treatment adherence.

METHODS

Eligible patients were adults (aged ≥18 years), independent in activities of daily living, who had prehospital stroke symptoms with a duration of less than 4 hours. They were randomized to RIC or sham. The RIC treatment protocol consisted of 5 cycles with 5 minutes of cuff inflation alternating with 5 minutes with a deflated cuff. Acceptable treatment adherence was defined as when at least 80% of planned RIC cycles were received. The analysis was performed using the entire range (shift analysis) of the modified Rankin Scale (ordinal logistic regression).

RESULTS

A total of 698 had acute ischemic stroke, 253 (36%) were women, and the median (interquartile range) age was 73 (63-80) years. Median (interquartile range) overall adherence to RIC/sham was 91% (68%-100%). In patients with a stroke due to cerebral small vessel disease, who were adherent to treatment, RIC was associated with improved functional outcome, and the odds ratio for a shift to a lower score on the modified Rankin Scale was 2.54 (1.03-6.25); P=0.042. The association remained significant after adjusting for potential confounders. No significant associations were found with other stroke etiologies, and the overall test for interaction was not statistically significant (χ2, 4.33, P=0.23).

CONCLUSIONS

In patients with acute ischemic stroke due to cerebral small vessel disease, who maintained good treatment adherence, RIC was associated with improved functional outcomes at 90 days. These results should only serve as a hypothesis-generating for future trials.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03481777.

Neuroprotection during Thrombectomy for Acute Ischemic Stroke: A Review of Future Therapies

Stroke is a major cause of death and disability worldwide. Endovascular thrombectomy has been impactful in decreasing mortality. However, many clinical results continue to show suboptimal functional outcomes despite high recanalization rates. This gap in recanalization and symptomatic improvement suggests a need for adjunctive therapies in post-thrombectomy care. With greater insight into ischemia-reperfusion injury, recent preclinical testing of neuroprotective agents has shifted towards preventing oxidative stress through upregulation of antioxidants and downstream effectors, with positive results. Advances in multiple neuroprotective therapies, including uric acid, activated protein C, nerinetide, otaplimastat, imatinib, verapamil, butylphthalide, edaravone, nelonemdaz, ApTOLL, regional hypothermia, remote ischemic conditioning, normobaric oxygen, and especially nuclear factor erythroid 2-related factor 2, have promising evidence for improving stroke care. Sedation and blood pressure management in endovascular thrombectomy also play crucial roles in improved stroke outcomes. A hand-in-hand approach with both endovascular therapy and neuroprotection may be the key to targeting disability due to stroke.

Outcomes Following Adherence to a Randomized Stroke Trial Protocol

This secondary analysis of a randomized clinical trial assesses whether compliance with the study protocol is associated with a better functional outcome even among participants in the sham-control group.

Cardiovascular Prognosis in Patients with Peripheral Artery Disease and Approach to Therapy

Peripheral artery disease (PAD), the pathophysiologic narrowing of the arterial blood vessels of the lower limbs due to atherosclerosis, is estimated to affect more than 200 million people worldwide and its prevalence ranges from 0.9 to 31.3% in people aged ≥50 years. It is an established marker of systemic obstructive atherosclerosis, which depicts patients at higher risk of myocardial infarction and stroke, due to the involvement of coronary and cerebral arteries in the atherosclerotic process. Therefore, identifying PAD, particularly in patients with coronary artery disease, is important to assess the cardiovascular risk score and implement specific therapies and prevention strategies. Since PAD emerged as an important clinical cardiovascular predictor, even more than other typical cardiovascular risk factors, an aggressive strategy to identify and treat PAD patients should be pursued by general practitioners, cardiologists, and vascular surgeons; similarly, preventive strategies should be implemented to improve prognosis and outcomes, particularly in patients suffering from both coronary artery disease and PAD. In this review, we describe the pathophysiology, including limb vasoconstriction after coronary angioplasty, the diagnosis of PAD, prognosis according to cardiovascular events, coronary artery disease, and heart failure. Furthermore, a large section of this review is on management, which spans from risk factors' modification to antithrombotic therapy, and revascularization is provided. Finally, considerations about newer therapeutic options for the "desert foot" are discussed, including gene therapy.

Evolving Clinical-Translational Investigations of Cerebroprotection in Ischemic Stroke

Ischemic stroke is a highly morbid disease, with over 50% of large vessel stroke (middle cerebral artery or internal carotid artery terminus occlusion) patients suffering disability despite maximal acute reperfusion therapy with thrombolysis and thrombectomy. The discovery of the ischemic penumbra in the 1980s laid the foundation for a salvageable territory in ischemic stroke. Since then, the concept of neuroprotection has been a focus of post-stroke care to (1) minimize the conversion from penumbra to core irreversible infarct, (2) limit secondary damage from ischemia-reperfusion injury, inflammation, and excitotoxicity and (3) to encourage tissue repair. However, despite multiple studies, the preclinical-clinical research enterprise has not yet created an agent that mitigates post-stroke outcomes beyond thrombolysis and mechanical clot retrieval. These translational gaps have not deterred the scientific community as agents are under continuous investigation. The NIH has recently promoted the concept of cerebroprotection to consider the whole brain post-stroke rather than just the neurons. This review will briefly outline the translational science of past, current, and emerging breakthroughs in cerebroprotection and use of these foundational ideas to develop a novel paradigm for optimizing stroke outcomes.