rt-PA with remote ischemic postconditioning for acute ischemic stroke

Research progress on the mechanism of action and clinical application of remote ischemic post-conditioning for acute ischemic stroke

Remote ischemic post-conditioning (RIPostC) can reduce cerebral ischemia reperfusion injury (IRI) by inducing endogenous protective effects, the distal limb ischemia post-treatment and in situ ischemia post-treatment were classified according to the site of intervention. And in the process of clinical application distal limb ischemia post-treatment is more widely used and more conducive to clinical translation. Therefore, in this paper, we review the mechanism of action and clinical application of RIPostC in cerebral ischemia, hoping to provide reference help for future experimental directions and clinical translation.

Remote Ischemic Conditioning in Stroke Recovery

Remote ischemic conditioning (RIC) is a therapeutic strategy to protect a vital organ like the brain from ischemic injury through brief and repeat cycles of ischemia and reperfusion in remote body parts such as arm or leg. RIC has been applied in different aspects of the stroke field and has shown promise. This narrative review will provide an overview of how to implement RIC in stroke patients, summarize the clinical evidence of RIC on stroke recovery, and discuss unresolved questions and future study directions.

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.

Remote ischemic conditioning after stroke: Research progress in clinical study

BACKGROUND AND PURPOSE

Stroke is a leading cause of global morbidity and mortality, indicating the necessity and urgency of effective prevention and treatment. Remote ischemic conditioning (RIC) is a convenient, simple, non-intrusive, and effective method that can be easily added to the treatment regime of stroke patients. Animal experiments and clinical trials have proved the neuroprotective effects of RIC on brain injury including (examples of neuroprotective effects). This neuroprotection is achieved by raising brain tolerance to ischemia, increasing local cerebral blood perfusion, promoting collateral circulations, neural regeneration, and reducing the incidence of hematomas in brain tissue. This current paper will summarize the studies within the last 2 years for the comprehensive understanding of the use of RIC in the treatment of stroke.

METHODS

This paper summarizes the clinical research progress of RIC on stroke (ischemic stroke and hemorrhagic stroke (HS)). This paper is a systematic review of research published on registered clinical trials using RIC in stroke from inception through November 2022. Four major databases (PUBMED, WEB OF SCIENCE, EMBASE, and ClinicalTrials.gov) were searched.

RESULTS

Forty-eight studies were identified meeting our criteria. Of these studies, 14 were in patients with acute ischemic stroke with onset times ranging from 6 h to 14 days, seven were in patients with intravenous thrombolysis or endovascular thrombectomy, 10 were in patients with intracranial atherosclerotic stenosis, six on patients with vascular cognitive impairment, three on patients with moyamoya disease, and eight on patients with HS. Of the 48 studies, 42 were completed and six are ongoing.

CONCLUSIONS

RIC is safe, feasible, and effective in the treatment of stroke. Large-scale research is still required to explore the optimal treatment options and mechanisms of RIC in the future to develop a breakthrough in stroke prevention and treatment.

Construction and application of a time-saving mode in China for the treatment of acute ischemic stroke

Objective

To explore the construction and application in the practice of green channel in No. 971 Naval Hospital of PLA (No. 971 Hospital mode) for the treatment of acute ischemic stroke (AIS).

Methods

This retrospective study involved a cohort of 694 suspected stroke patients from December 2022 to November 2023 undergoing emergency treatment for stroke at our institution. Among them, 483 patients were treated with standard green channel (the control group), and 211 patients adopted the No. 971 Hospital mode for treatment (the study group). The biggest difference between the two groups was that the treatment process started before admission. We compared the effectiveness of the emergency treatment between the two groups and the thrombolysis treatment.

Results

Compared with control group, the accuracy rate of determining stroke and the rate of thrombolysis were significantly higher (p = 0.002, 0.039) and the door to doctor arrival time (DAT) and the door to CT scan time (DCT) of the study group was significantly shorter (all p < 0.001). There were 49 patients (10.1%) and 33 patients (15.6%) from the control group and study group receiving thrombolysis, respectively. The DAT, DCT, imaging to needle time (INT), and door to needle time (DNT) of patients receiving thrombolysis in the study group were significantly shorter than that in the control group (all p < 0.01). The NIHSS in the study group after the thrombolysis was lower than that in the control group (p = 0.042).

Conclusion

No. 971 Hospital model can effectively shorten DAT, DCT, INT, and DNT, and improve the effectiveness of thrombolysis and prognoses of AIS patients.

Remote ischemic conditioning for stroke: A critical systematic review

Remote ischemic conditioning (RIC) is the application of brief periods of ischemia to an organ or tissue with the aim of inducing protection from ischemia in a distant organ. It was first developed as a cardioprotective strategy but has been increasingly investigated as a neuroprotective intervention. The mechanisms by which RIC achieves neuroprotection are incompletely understood. Preclinical studies focus on the hypothesis that RIC can protect the brain from ischemia reperfusion (IR) injury following the restoration of blood flow after occlusion of a large cerebral artery. However, increasingly, a role of chronic RIC (CRIC) is being investigated as a means of promoting recovery following an ischemic insult to the brain. The recent publication of two large, randomized control trials has provided promise that RIC could improve functional outcomes after acute ischemic stroke, and that there may be a role for CRIC in the prevention of recurrent stroke. Although less developed, there is also proof-of-concept to suggest that RIC may be used to reduce vasospasm after subarachnoid hemorrhage or improve cognitive outcomes in vascular dementia. As a cheap, well-tolerated and almost universally applicable intervention, the motivation for investigating possible benefit of RIC in patients with cerebrovascular disease is great. In this review, we shall review the current evidence for RIC as applied to cerebrovascular disease.

Baseline neurologic deficit and efficacy of remote ischemic conditioning after acute ischemic stroke: A post hoc analysis of RICAMIS

RICAMIS (ClinicalTrials.gov Identifier: NCT03740971) trial has demonstrated efficacy of remote ischemic conditioning (RIC) in acute ischemic stroke, but whether baseline NIHSS score can affect outcomes in stroke remains unclear. We conducted a post hoc analysis of RICAMIS to investigate the issue. Patients included in RICAMIS were divided into three groups based on baseline NIHSS score. The primary outcome was excellent functional outcome at 90 days, defined as mRS score of 0-1. Compared with patients receiving usual care, we investigated association of RIC effect with outcomes in each group and interaction between RIC effect and stroke severity. Among 1776 patients, 1255 were assigned into NIHSS score 6-8 group, 402 into NIHSS score 9-12 group, and 119 into NIHSS score 13-16 group. A higher proportion of primary outcome was found associated with RIC in NIHSS score 9-12 group (adjusted risk difference [RD], 14.6 ​%; 95 ​% CI, 5.0 ​%-24.2 ​%; P ​= ​0.003), but no significant association was found in NIHSS score 6-8 group (adjusted RD, 2.3 ​%; 95 ​% CI, -2.5 ​%-7.2 ​%; P ​= ​0.34), or in NIHSS score 13-16 group (adjusted RD, 9.7 ​%; 95 ​% CI, -7.5 ​%-26.9 ​%; P ​= ​0.27). There was a significant interaction between RIC effect and stroke severity when analysis was performed between NIHSS score 6-8 and 9-12 groups (P ​= ​0.04), but not between NIHSS score 9-12 and 13-16 groups (P ​= ​0.57). Current study firstly reported patients with NIHSS score 9-12 may get more benefit from RIC after stroke with respect to excellent functional outcome at 90 days.

Remote Ischemic Conditioning for Motor Recovery after Acute Ischemic Stroke

BACKGROUND

Remote ischemic conditioning (RIC) has shown an impressive neuroprotective effect on acute ischemic stroke (AIS) in animal experiments. But whether chronic RIC improves long-term functional outcomes remains unclear.

MATERIALS AND METHODS

We performed a non-randomized controlled trial. Eligible patients (aged 18 -80 y) with hemiplegia caused by AIS were allocated to the RIC group and the control group. All participants received normal protocol rehabilitation therapy. Patients in the RIC group underwent RIC twice daily for 90 days. The outcome included the 90-day Fugl-Meyer Assessment (FMA) scores and modified Rankin's scale (mRS) scores, as well as changes in angiogenesis-related factors in serum from baseline to 90 days.

RESULTS

Twenty-seven patients were included in the analysis (13 in the RIC group and 14 in the control group). There was no significant difference in 90-day total FMA scores between the two groups. Lower limb FMA scores at day 90 were significantly higher in the RIC group (32.8±8.7 vs. 24.8±5.4, adjusted P =0.042). The proportion of favorable outcome (mRS<2) was higher in the RIC group than that in the control group, but no significant difference was detected (8 [61.5%] vs. 7 [50%], P =0.705). A significant increase has been found in the level of epidermal growth factor (EGF) in serum (9.4 [1.1 to 25.7] vs. -8.7 [-15.1 to 4.7], P =0.036) after chronic RIC procedure.

CONCLUSION

This study investigated the role that RIC plays in AIS recovery, especially in motor function. RIC may have beneficial effects on lower limbs recovery by enhancing the EGF level. The effect of RIC on motor recovery should be further validated in future studies.

Autonomic function may mediate the neuroprotection of remote ischemic postconditioning in stroke: A randomized controlled trial

OBJECTIVES

To evaluate the effect of remote ischemic postconditioning (RIPostC) on the prognosis of acute ischemic stroke(AIS) patients and investigate the mediating role of autonomic function in the neuroprotection of RIPostC.

MATERIALS AND METHODS

132 AIS patients were randomized into two groups. Patients received four cycles of 5-min inflation to a pressure of 200 mmHg(i.e., RIPostC) or patients' diastolic BP(i.e., shame), followed by 5 min of deflation on healthy upper limbs once a day for 30 days. The main outcome was neurological outcome including the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel index(BI). The second outcome measure was autonomic function measured by heart rate variability(HRV).

RESULTS

Compared with the baseline, the post-intervention NIHSS score was significantly reduced in both groups (P<0.001). NIHSS score was significantly lower in the control group than intervention group at day 7.[RIPostC:3(1,5) versus shame:2(1,4); P=0.030]. mRS scored lower in the intervention group compared with the control group at day 90 follow-up(RIPostC:0.5±2.0 versus shame:1.0±2.0;P=0.016). The goodness-of-fit test revealed a significant difference between the generalized estimating equation model of mRS and BI scores of uncontrolled-HRV and controlled-HRV(P<0.05, both). The results of bootstrap revealed a complete mediation effect of HRV between group on mRS[indirect effect: -0.267 (LLCI = -0.549, ULCI = -0.048), the direct effect: -0.443 (LLCI = -0.831, ULCI = 0.118)].

CONCLUSION

This is the first human-based study providing evidence for a mediation role of autonomic function between RIpostC and prognosis in AIS patients. It indicated that RIPostC could improve the neurological outcome of AIS patients. Autonomic function may play a mediating role in this association.

TRIAL REGISTRATION

The clinical trials registration number for this study is NCT02777099 (ClinicalTrials.gov Identifier).

Efficacy and safety of remote ischemic conditioning for acute ischemic stroke: A comprehensive meta-analysis from randomized controlled trials

BACKGROUND AND PURPOSE

Remote ischemic conditioning (RIC) is a remote, transient, and noninvasive procedure providing temporary ischemia and reperfusion. However, there is no comprehensive literature investigating the efficacy and safety of RIC for the treatment of acute ischemic stroke. In the present study, we performed a comprehensive meta-analysis of the available studies.

METHODS

MEDLINE, Embase, the Cochrane Library database (CENTRAL), and ClinicalTrials.gov were searched before Sep 7, 2022. The data were analyzed using Review Manager 5.4.1 software, Stata version 16.0 software, and R 4.2.0 software. Odds ratio (OR), mean difference (MD), and corresponding 95% CIs were pooled using fixed-effects meta-analysis.

RESULTS

We pooled 6392 patients from 17 randomized controlled trials. Chronic RIC could reduce the recurrence of ischemic stroke at the endpoints (OR 0.67, 95% CI [0.51, 0.87]). RIC could also improve the prognosis of patients at 90 days as assessed by mRS score (mRS 0-1: OR 1.29, 95% CI [1.09, 1.52]; mRS 0-2: OR 1.22, 95% CI [1.01, 1.48]) and at the endpoints assessed by NIHSS score (MD -0.99, 95% CI [-1.45, -0.53]). RIC would not cause additional adverse events such as death (p = 0.72), intracerebral hemorrhage events (p = 0.69), pneumonia (p = 0.75), and TIA (p = 0.24) but would inevitably cause RIC-related adverse events (OR 26.79, 95% CI [12.08, 59.38]).

CONCLUSIONS

RIC could reduce the stroke recurrence and improve patients' prognosis. Intervention on bilateral upper limbs, 5 cycles, and a length of 50 min in each intervention might be an optimal protocol for RIC at present. RIC could be an effective therapy for patients not eligible for reperfusion therapy. RIC would not cause other adverse events except for relatively benign RIC-related adverse events.

Safety and efficacy of remote ischemic conditioning combined with intravenous thrombolysis for acute ischemic stroke: A multicenter, randomized, parallel-controlled clinical trial (SERIC-IVT) Study design and protocol

RATIONALE

Remote ischemic conditioning (RIC) combined with intravenous thrombolysis (IVT) may improve functional outcomes in patients with acute ischemic stroke (AIS).

AIM

To assess the efficacy and safety of RIC combined with IVT for AIS.

METHODS AND DESIGN

SERIC-IVT is a multicenter, randomized, parallel-controlled, blinded endpoint clinical trial. A total of 558 patients with AIS who underwent IVT therapy will be randomly assigned 1:1 to receive RIC or sham-RIC plus standard medical therapy. The cuff pressures of the RIC group and the sham-RIC group will be 200 mm Hg and 60 mm Hg, respectively, performed twice a day for seven consecutive days.

STUDY OUTCOMES

The primary efficacy outcome is the proportion of patients with a favorable functional outcome as defined as a modified Rankin Scale ⩽ 1 at 90 days. Safety outcomes include mortality and adverse events within 90 days.

SAMPLE SIZE ESTIMATES

A sample size of 558 patients with AIS (279 in each group) will allow detection of a shift of 13.14% toward favorable functional outcome at 90 days (modified Rankin Scale ⩽ 1) with 5% significance and 80% power.

DISCUSSION

RIC is a promising adjuvant treatment for AIS. SERIC-IVT will inform on whether RIC treatment combined with IVT improves functional outcomes in AIS patients and identify any safety issues.

Remote ischemic conditioning attenuates blood-brain barrier disruption after recombinant tissue plasminogen activator treatment via reducing PDGF-CC

Treatment of acute ischemic stroke with the recombinant tissue plasminogen activator (rtPA) is associated with increased blood-brain barrier (BBB) disruption and hemorrhagic transformation. Remote ischemic conditioning (RIC) has demonstrated neuroprotective effects against acute ischemic stroke. However, whether and how RIC regulates rtPA-associated BBB disruption remains unclear. Here, a rodent model of thromboembolic stroke followed by rtPA thrombolysis at different time points was performed with or without RIC. Brain infarction, neurological outcomes, BBB permeability, and intracerebral hemorrhage were assessed. The platelet-derived growth factor CC (PDGF-CC)/PDGFRα pathway in the brain tissue, PDGF-CC levels in the skeletal muscle and peripheral blood were also measured. Furthermore, impact of RIC on serum PDGF-CC levels were measured in healthy subjects and AIS patients. Our results showed that RIC substantially reduced BBB injury, intracerebral hemorrhage, cerebral infarction, and neurological deficits after stroke, even when rtPA was administrated in a delayed therapeutic time window. Mechanistically, RIC significantly decreased PDGFRα activation in ischemic brain tissue and reduced blood PDGF-CC levels, which partially resulted from PDGF-CC reduction in the skeletal muscle of RIC-applied hindlimbs and platelets. Intravenous or intraventricular recombinant PDGF-CC supplementation abolished RIC protective effects on BBB integrity. Moreover, similar changes of PDGF-CC in serum by RIC were also observed in healthy humans and acute ischemic stroke patients. Together, our study demonstrates that RIC can attenuate rtPA-aggravated BBB disruption after ischemic stroke via reducing the PDGF-CC/PDGFRα pathway and thus supports RIC as a potential approach for BBB disruption prevention or treatment following thrombolysis.

MicroRNA-27a Regulates Ferroptosis Through SLC7A11 to Aggravate Cerebral ischemia-reperfusion Injury

Cerebral ischemia-reperfusion (I/R) injury is an inevitable issue in the treatment of ischemic stroke, which has a high disability rate and seriously threatens the living quality of patients. Previous studies have demonstrated that ferroptosis, which plays a crucial role in ischemia-reperfusion injury, can be accelerated by microRNA-27a (miR-27a). However, the mechanism by which miR-27a regulates ferroptosis in cerebral ischemia-reperfusion injury remains unknown. In this study, Male Sprague-Dawley rats were subjected to a middle cerebral artery occlusion (MCAO), then restored blood flow. Neurological function score and TTC staining were used to evaluate brain tissue injury and the infarct volume. The relative expression level of miR-27a was detected by qPCR. The relative expression levels of glutathione peroxidase 4(GPx4), solute carrier family 7 member 11 (SLC7A11) proteins were analyzed by Western Blot. The contents of GSH, Fe and malonaldehyde (MDA) were detected by corresponding detection kits, and the target gene of miR-27a was confirmed by dual luciferase reporter gene technique. It was found the relative expression level of miR-27a was increased and ferroptosis was aggravated as reperfusion time went by. Also, brain tissue injury and ferroptosis were exacerbated with agomiR-27a intervention, while these effects were reversed with antagomiR-27a intervention. In addition, the combined intervention of agomiR-27a and Fer-1 alleviated the brain tissue injury and ferroptosis. The results of dual luciferase reporter gene technique indicated SLC7A11 as the target gene of miR-27a. In the current study, miR-27a upregulates ferroptosis to aggravate cerebral ischemia-reperfusion injury by SLC7A11.

Effects of Danhong injection combined with tirofiban on cardiac function, myocardial enzyme spectrum and lipoprotein-associated phospholipase A2 level in patients with acute myocardial infarction

OBJECTIVE

To determine the effect of Danhong injection combined with tirofiban on cardiac function, myocardial enzyme spectrum and lipoprotein-associated phospholipase A2 (Lp-PLA2) level in patients with acute myocardial infarction (AMI).

METHODS

The clinical data of 124 AMI patients who were treated in the Second Affiliated Hospital of Wenzhou Medical University from August 2019 to April 2021 were collected and analyzed retrospectively. Among them, 58 patients treated with routine thrombolysis combined with tirofiban were assigned to the control group, and the other 66 patients treated with Danhong injection on the basis of treatment to the control group were assigned to the observation group. Treatment efficacy, cardiac function, myocardial enzyme spectrum, and Lp-PLA2 level before and after treatment, and adverse cardiovascular events during treatment were compared between the two groups. The patients were further grouped into an occurrence group and a non-occurrence group in the light of the occurrence of adverse cardiovascular events after treatment, and then the risk factors of adverse cardiovascular events were analyzed by logistic regression.

RESULTS

The control group showed a notably lower total effective rate than the observation group (P=0.015). After treatment, the observation group showed a higher left ventricular ejection fraction (LVEF) level and a lower left ventricular end-diastolic dimension (LVEDD) than the control group (both P < 0.05). In addition, the observation group showed lower levels of CK, CK-MB and Lp-PLA2 than the control group (all P < 0.05). A significantly higher incidence of adverse cardiovascular events was found in the control group than that in the observation group (P=0.039), and Logistic regression analysis showed that NYHA grade, LVEF, LVEDD, CK-MB and Lp-PLA2 were independent risk factors (P < 0.05). The prediction model =-86.255 + (4.645*NYHA grade) + (-0.581*LVEF) + (1.058*LVEDD) + (0.263*CK-MB) + (0.121*Lp-PLA2). According to the ROC curve analysis, the area under the curve of the model in predicting adverse cardiovascular events among patients was 0.970.

CONCLUSION

Danhong injection combined with tirofiban can improve the cardiac function, myocardial enzyme spectrum and Lp-PLA2 level in AMI patients.

The BE COOL Treatments (Batroxobin, oxygEn, Conditioning, and cOOLing): Emerging Adjunct Therapies for Ischemic Cerebrovascular Disease

Ischemic cerebrovascular disease (ICD), the most common neurological disease worldwide, can be classified based on the onset time (acute/chronic) and the type of cerebral blood vessel involved (artery or venous sinus). Classifications include acute ischemic stroke (AIS)/transient ischemic attack (TIA), chronic cerebral circulation insufficiency (CCCI), acute cerebral venous sinus thrombosis (CVST), and chronic cerebrospinal venous insufficiency (CCSVI). The pathogenesis of cerebral arterial ischemia may be correlated with cerebral venous ischemia through decreased cerebral perfusion. The core treatment goals for both arterial and venous ICDs include perfusion recovery, reduction of cerebral ischemic injury, and preservation of the neuronal integrity of the involved region as soon as possible; however, therapy based on the current guidelines for either acute ischemic events or chronic cerebral ischemia is not ideal because the recurrence rate of AIS or CVST is still very high. Therefore, this review discusses the neuroprotective effects of four novel potential ICD treatments with high translation rates, known as the BE COOL treatments (Batroxobin, oxygEn, Conditioning, and cOOLing), and subsequently analyzes how BE COOL treatments are used in clinical settings. The combination of batroxobin, oxygen, conditioning, and cooling may be a promising intervention for preserving ischemic tissues.

Cerebral protection by remote ischemic post-conditioning in patients with ischemic stroke: A systematic review and meta-analysis of randomized controlled trials

Background

There is evidence that remote limb ischemic postconditioning (RIPostC) can reduce ischemia-reperfusion injury (IRI) and improve the prognosis of patients with ischemic stroke. However, so far, only few relevant clinical studies have been conducted. Therefore, we carried out a meta-analysis of eligible randomized controlled trials to compare the RIPostC group with a control group (no intervention or sham surgery) in patients with ischemic stroke.

Methods

Four English-language publication databases, PubMed, Cochrane, Embase, and Web of Science, were systematically searched up to March 2022. The data were analyzed using Review Manager fixed-effects and random-effects models.

Results

A total of 12 studies were included, and 11 of those were analyzed quantitatively. Compared to controls, The RIPostC group showed significantly reduced NIHHS scores in patients with ischemic stroke, (MD: −1.09, 95% confidence interval [CI]: −1.60, −0.57, P < 0.0001) and improved patients' Montreal Cognitive Assessment (MoCA) scores, (MD: 1.89, 95% CI: 0.78, 3.00, P = 0.0009), Our results showed that RIPostC is safe, (RR = 0.81, 95%CI: 0.61, 1.08, P = 0.15).

Conclusion

Our meta-analysis showed that RIPostC is safe and effective and has a positive cerebral protective effect in patients with ischemic stroke, which is safe and effective, and future large-sample, multicenter trials are needed to validate the cerebral protective effect of RIPostC.

Electroacupuncture treatment improves motor function and neurological outcomes after cerebral ischemia/reperfusion injury

Electroacupuncture (EA) has been widely used for functional restoration after stroke. However, its role in post-stroke rehabilitation and the associated regulatory mechanisms remain poorly understood. In this study, we applied EA to the Zusanli (ST36) and Quchi (LI11) acupoints in rats with middle cerebral artery occlusion and reperfusion. We found that EA effectively increased the expression of brain-derived neurotrophic factor and its receptor tyrosine kinase B, synapsin-1, postsynaptic dense protein 95, and microtubule-associated protein 2 in the ischemic penumbra of rats with middle cerebral artery occlusion and reperfusion. Moreover, EA greatly reduced the expression of myelin-related inhibitors Nogo-A and NgR in the ischemic penumbra. Tyrosine kinase B inhibitor ANA-12 weakened the therapeutic effects of EA. These findings suggest that EA can improve neurological function after middle cerebral artery occlusion and reperfusion, possibly through regulating the activity of the brain-derived neurotrophic factor/tyrosine kinase B signal pathway. All procedures and experiments were approved by the Animal Research Committee of Shanghai University of Traditional Chinese Medicine, China (approval No. PZSHUTCM200110002) on January 10, 2020.

Remote Ischemic Conditioning in Ischemic Stroke and Myocardial Infarction: Similarities and Differences

Acute myocardial infarction and ischemic stroke are leading causes of morbidity and mortality worldwide. Although reperfusion therapies have greatly improved the outcomes of patients with these conditions, many patients die or are severely disabled despite complete reperfusion. It is therefore important to identify interventions that can prevent progression to ischemic necrosis and limit ischemia-reperfusion injury. A possible strategy is ischemic conditioning, which consists of inducing ischemia – either in the ischemic organ or in another body site [i.e., remote ischemic conditioning (RIC), e.g., by inflating a cuff around the patient's arm or leg]. The effects of ischemic conditioning have been studied, alone or in combination with revascularization techniques. Based on the timing (before, during, or after ischemia), RIC is classified as pre-, per-/peri-, or post-conditioning, respectively. In this review, we first highlight some pathophysiological and clinical similarities and differences between cardiac and cerebral ischemia. We report evidence that RIC reduces circulating biomarkers of myocardial necrosis, infarct size, and edema, although this effect appears not to translate into a better prognosis. We then review cutting-edge applications of RIC for the treatment of ischemic stroke. We also highlight that, although RIC is a safe procedure that can easily be implemented in hospital and pre-hospital settings, its efficacy in patients with ischemic stroke remains to be proven. We then discuss possible methodological issues of previous studies. We finish by highlighting some perspectives for future research, aimed at increasing the efficacy of ischemic conditioning for improving tissue protection and clinical outcomes, and stratifying myocardial infarction and brain ischemia patients to enhance treatment feasibility.

The neuroprotective effect and RNA-sequence analysis of postconditioning on the ischemic stroke with diabetes mellitus tree shrew model

INTRODUCTION

Patients with comorbidity of ischemic stroke (IS) and diabetes mellitus (DM) show poor neurological functional recovery, and ischemic postconditioning (IPOC) should be considered a powerful neuroprotective method for IS. However, whether it should be introduced for patients with IS and DM remains controversial. This study established a DM with IS (DMIS) tree shrew model, which was intervened by IPOC to assess its neuroprotective effects and also to analyze the relevant mechanism by RNA-sequence and bioinformatics analysis.

METHODS

Fifty-four tree shrews were randomly divided into a sham operation control group, a DMIS group, and an IPOC group (DMIS model), with 18 tree shrews per group. Triphenyl tetrazolium chloride (TTC), hematoxylin-eosin (HE) staining, transmission electron microscopy (TEM), and RNA-sequence analysis were performed to assess the IPOC effect.

RESULTS

IPOC reduced infarct size and reduced nerve cell injury in IS tree shrews with DM. RNA-seq analysis showed that IPOC significantly increased the expression of the homeobox protein SIX3, while downregulating the expression of HLA class II histocompatibility antigens DQ beta 1 chain, CAS1 domain-containing protein 1, and cytokine receptor-like factor 2. The most downregulated signaling pathways include the NF-κB signaling pathway, TNF signaling pathway, and Fc gamma R-mediated phagocytosis.

CONCLUSIONS

IPOCs have a neuroprotective effect in a DMIS animal model that reduces infarct size and nerve cell injury. This mechanism might be related to reducing inflammation and stress responses that decreases the activity of TNF and NF-κB signaling pathways.

Remote Ischemic Conditioning May Improve Disability and Cognition After Acute Ischemic Stroke: A Pilot Randomized Clinical Trial

Background and Aim: Remote ischemic conditioning is a procedure purported to reduce the ischemic injury of an organ. This study aimed to explore the efficiency and safety of remote ischemic conditioning in patients with acute ischemic stroke. We hypothesized that remote ischemic conditioning administered from the first day of hospital admission would improve the infarct volume and clinical outcome at 180 days. Material and Methods: We performed a unicentric double-blind randomized controlled trial. We included all patients consecutively admitted to an Emergency Neurology Department with acute ischemic stroke, ineligible for reperfusion treatment, up to 24 hours from onset. All subjects were assigned to receive secondary stroke prevention treatment along with remote ischemic conditioning on the non-paretic upper limb during the first 5 days of hospitalization, twice daily - a blood pressure cuff placed around the arm was inflated to 20 mmHg above the systolic blood pressure (up to 180 mmHg) in the experimental group and 30 mmHg in the sham group. The primary outcome was the difference in infarct volume (measured on brain CT scan) at 180 days compared to baseline, whereas the secondary outcomes included differences in clinical scores (NIHSS, mRS, IADL, ADL) and cognitive/mood changes (MoCA, PHQ-9) at 180 days compared to baseline. Results: We enrolled 40 patients; the mean age was 65 years and 60% were men. Subjects in the interventional group had slightly better recovery in terms of disability, as demonstrated by the differences in disability scores between admission and 6 months (e.g., the median difference score for Barthel was -10 in the sham group and -17.5 in the interventional group, for ADL -2 in the sham group and -2.5 in the interventional group), as well as cognitive performance (the median difference score for MoCA was -2 in the sham group and -3 in the interventional group), but none of these differences reached statistical significance. The severity of symptoms (median difference score for NIHSS = 5 for both groups) and depression rate (median difference score for PHQ-9 = 0 for both groups) were similar in the two groups. The median difference between baseline infarct volume and final infarct volume at 6 months was slightly larger in the sham group compared to the interventional group (p = 0.4), probably due to an initial larger infarct volume in the former. Conclusion: Our results suggest that remote ischemic conditioning might improve disability and cognition. The difference between baseline infarct volume and final infarct volume at 180 days was slightly larger in the sham group.

Limb Remote Ischemic Conditioning Ameliorates Cognitive Impairment in Rats with Chronic Cerebral Hypoperfusion by Regulating Glucose Transport

Cognitive impairment is closely associated with the slowing of glucose metabolism in the brain. Glucose transport, a rate-limiting step of glucose metabolism, plays a key role in this phenomenon. Previous studies have reported that limb remote ischemic conditioning (LRIC) improves cognitive performance in rats with chronic cerebral hypoperfusion (CCH). Here, we determined whether LRIC could ameliorate cognitive impairment in rats with CCH by regulating glucose transport. A total of 170 male Sprague-Dawley rats were used. Animals subjected to permanent double carotid artery occlusion (2VO) were assigned to the control or LRIC treatment group. LRIC was applied beginning 3 days after the 2VO surgery. We found that LRIC can improve learning and memory; decrease the ratio of ADP/ATP; increase glucose content; upregulate the expression of pAMPKα, GLUT1 and GLUT3; and increase the number of GLUT1 and GLUT3 transporters in cerebral cortical neurons. The expression of GLUT1 and GLUT3 in the cortex displayed a strong correlation with learning and memory. Pearson correlation analysis showed that the levels of GLUT1 and GLUT3 are correlated with neurological function scores. All of these beneficial effects of LRIC were ablated by application of the AMPK inhibitor, dorsomorphin. In summary, LRIC ameliorated cognitive impairment in rats with CCH by regulating glucose transport via the AMPK/GLUT signaling pathway. We conclude that AMPK-mediated glucose transport plays a key role in LRIC. These data also suggest that supplemental activation of glucose transport after CCH may provide a clinically applicable intervention for improving cognitive impairment.

Per- and post-remote ischemic conditioning attenuates ischemic brain injury via inhibition of the TLR4/MyD88 signaling pathway in aged rats

Remote ischemic conditioning (RIC), as an emerging protective method, might be used clinically to prevent ischemia-reperfusion injury (IRI) in ischemic stroke. In this study, we aim to investigate whether RIC performed either during brain ischemia or after reperfusion has a protective effect and further explore the mechanistic basis for the protective effects of RIC against IRI in an aged rat model. We investigated brain IRI in 16-18 months old SD rats. Animals underwent: (i) sham laparotomy, (ii) brain IRI, (iii) brain IRI  +  RIC during ischemia (IRI  +  RIperC), or (iv) brain IRI  +  RIC after reperfusion (IRI  +  RIpostC). RIC consists of three cycles of 10 min of hind limb ischemia followed by 10 min reperfusion. After 24 h of reperfusion, the infarct size, neurological deficit scores and brain oedema were assessed in all groups. The levels of IL-1β, IL-6, TNF-α were measured by ELISA. The mRNA and protein expressions of TLR4, MyD88, TRAF6 and NF-κB were detected by RT-PCR and western blot. Both RIperC and RIpostC treatment attenuated the IRI-induced neuronal injury, reflected by reductions in the infarct size, neurological deficit scores and brain oedema. RIperC and RIpostC also can decrease the concentration of IL-1β, IL-6, TNF-α in IRI. From the results of RT-PCR and western blot, we found that RIC decreased the mRNA and protein expression of TLR4, MyD88, TRAF6 and NF-κB compared to that in the IRI group. The present study suggested that RIC protected aged rats against IRI, and this protective effect might be mediated by inhibiting the TLR-4/MyD88/TRAF-6/NF-κB signaling pathway.

Translational challenges of remote ischemic conditioning in ischemic stroke - a systematic review

Remote ischemic conditioning (RIC) has well‐established cardioprotective effects in preclinical studies and promising results in preclinical stroke research. Effective translation from preclinical studies to clinical trials has yet to be accomplished, perhaps because of the use of multiple applications of RIC (e.g., pre‐, per‐, or post‐conditioning) in preclinical studies by both invasive and non‐invasive protocols, some of which not clinically applicable. Our systematic review conformed to PRISMA guidelines and addressed differences in clinically relevant RIC applications and outcomes between preclinical and clinical studies. We retrieved a total of 30 studies (8 human; 22 animal) that met the inclusion criteria of testing clinically relevant procedures; namely, non‐invasive and per‐ or post‐conditioning protocols. Per‐conditioning was applied in 6 animal and 3 human studies, post‐conditioning was applied in 16 animal and 5 human studies, and both conditioning methods were applied in 2 animal studies. Application of RIC varied between human and animal studies regarding initiation, duration, repetition, and number of limbs included. Study designs did not systematically apply blinding, randomization, or placebo controls. On only a few occasions did preclinical studies include animals with clinically relevant comorbidities. Clinical trials were challenged by not completing the intended number of RIC cycles or addressing this deficit in the data analysis. Consistency and transferability of methods used for positive animal studies and subsequent human studies are essential for the optimal translation of results. Consensus on preclinical and clinical RIC procedures should be reached for a full understanding of the possible beneficial effects of RIC treatment in stroke.

The application of the emergency green channel integrated management strategy in intravenous thrombolytic therapy for AIS

OBJECTIVE

To apply the emergency green channel integrated management strategy in intravenous thrombolytic therapy for acute ischemic stroke (AIS).

METHODS

This retrospective study involved a cohort of 82 AIS patients. Among them, 40 patients admitted to the emergency department of our hospital were treated using the emergency green channel integrated management strategy (the green channel group). Meanwhile, 42 AIS patients were rescued in accordance with the traditional grading and zoning treatment principles (the traditional group). The treatment times, the compliance rates of the times between when the patients entered the emergency department and when they underwent the thrombolysis treatment (the door-to-needle time or DNT), the neurological deficit scores, the Barthel index scores, and the ability of daily living scores before and after the treatment were compared between the two groups.

RESULTS

Compared with the traditional group, the triage times, the DNTs, the thrombolysis times, and the emergency department lengths of stay in the green channel group were significantly shorter (all P<0.001). The DNT compliance rate in the green channel group was significantly higher than it was in the traditional group (P<0.05). The neurological deficit scores in both groups after the treatment were lower than they were before the treatment (both P<0.01). The neurological deficit score in the green channel group after the treatment was lower than the neurological deficit score in the traditional group (P<0.01). The Barthel index and ability of daily living scores in the two groups after the treatment were significantly increased when compared with before the treatment (all P<0.001). The Barthel index and ability of daily living scores in the green channel group after the treatment were higher than they were in the traditional group (both P<0.001). The incidence of complications during the process of thrombolysis in the green channel group was significantly lower when compared with the incidence in the traditional group (P<0.05).

CONCLUSION

The emergency green channel integrated management strategy is more effective at shortening AIS patients' stays in the emergency department, increasing their DNT compliance rates, and at saving time for their thrombolytic therapy, improving patients' neurological function to a greater extent. It is worthy of clinical application.

Effect of remote ischemic preconditioning on cerebral vasospasm, biomarkers of cerebral ischemia, and functional outcomes in aneurysmal subarachnoid hemorrhage (ERVAS): A randomized controlled pilot trial

BACKGROUND:

Cerebral vasospasm can complicate aneurysmal subarachnoid hemorrhage (aSAH), contributing to cerebral ischemia. We explored the role of remote ischemic preconditioning (RIPC) in reducing cerebral vasospasm and ischemia and improving outcomes after aSAH.

MATERIALS AND METHODS:

Patients with ruptured cerebral aneurysm undergoing surgical clipping and meeting the trial criteria were randomized to true RIPC (n = 13) (inflating upper extremity blood pressure cuff thrice to 30 mmHg above systolic pressure for 5 min) or sham RIPC (n = 12) (inflating blood pressure cuff thrice to 30 mmHg for 5 min) after ethical approval. A blinded observer assessed outcome measures-cerebral vasospasm and biomarkers of cerebral ischemia. We also evaluated the feasibility and safety of RIPC in aSAH and Glasgow Outcome Scale-Extended (GOSE).

RESULTS:

Angiographic vasospasm was seen in 9/13 (69%) patients; 1/4 patients (25%) in true RIPC group, and 8/9 patients (89%) in sham RIPC group (P = 0.05). Vasospasm on transcranial Doppler study was diagnosed in 5/25 (20%) patients and 1/13 patients (7.7%) in true RIPC and 4/12 patients (33.3%) in sham RIPC group, (P = 0.16). There was no difference in S100B and neuron-specific enolase (NSE) levels over various time-points within groups (P = 0.32 and 0.49 for S100B, P = 0.66 and 0.17 for NSE in true and sham groups, respectively) and between groups (P = 0.56 for S100B and P = 0.31 for NSE). Higher GOSE scores were observed with true RIPC (P = 0.009) unlike sham RIPC (P = 0.847) over 6-month follow-up with significant between group difference (P = 0.003). No side effects were seen with RIPC.

CONCLUSIONS:

RIPC is feasible and safe in patients with aSAH and results in a lower incidence of vasospasm and better functional outcome.

Fibrinolysis and Remote Ischemic Conditioning: Mechanisms and Treatment Perspectives in Stroke

Stroke is a leading cause of death and disability. Intravenous thrombolysis and mechanical thrombectomy have greatly improved outcomes in acute ischemic stroke (AIS). However, only a minority of patients receive reperfusion therapies, highlighting the need for novel neuroprotective therapies. Remote ischemic conditioning (RIC), consisting of brief, intermittent extremity occlusion and reperfusion induced with an inflatable cuff, is a potential neuroprotective therapy in acute stroke. The objective of this narrative review is to describe the effect of RIC on endogenous fibrinolysis and, from this perspective, investigate the potential of RIC in the prevention and treatment of stroke. A systematic literature search was performed in PubMed, and human studies in English were included. Seven studies had investigated the effect of RIC on fibrinolysis in humans. Long-term daily administration of RIC increased endogenous fibrinolysis, whereas a single RIC treatment did not acutely influence endogenous fibrinolysis. Fifteen studies had investigated the effect of RIC as a neuroprotective therapy in the prevention and treatment of stroke. Long-term RIC administration proved effective in reducing new cerebral vascular lesions in patients with established cerebrovascular disease. In patients with acute stroke, RIC was safe and feasible, though its clinical efficacy as a neuroprotectant is yet unproven. In conclusion, a single RIC treatment does not affect fibrinolysis in the acute phase, whereas long-term RIC administration may increase endogenous fibrinolysis. Increased endogenous fibrinolysis is unlikely to be the mediator of the acute neuroprotective effect of RIC in stroke patients, whereas it may partly explain the reduced stroke recurrence associated with long-term RIC treatment.

Improvement of Cerebral Ischemia-Reperfusion Injury via Regulation of Apoptosis by Exosomes Derived from BDNF-Overexpressing HEK293

Brain-derived neurotrophic factor (BDNF) provides neuroprotective effects towards therapeutic cerebral ischemia-reperfusion (I/R) injury. This view has been proposed by more and more evidence. However, due to the lack of permeability of the blood-brain barrier (BBB) as well as the brief half-life in serum, clinical application is not widespread. To study the participation of exosomes containing BDNF in I/R, we isolated exosomes from BDNF-overexpressing HEK293. The protective outcomes of exosomes in hypoxia/reoxygenation (H/R) experiments were determined by the use of SY-5Y cells. Exosome-BDNF therapy restrained H/R-induced apoptosis by inhibition of the reducing levels of oxidative stress and calcium ions in the cells while maintaining stable levels of mitochondrial membrane potential in brain cells damaged by I/R. We then constructed a cerebral I/R injury model using SD rats to find the function of BDNF in exosome-mediated neuroprotection. The in vivo experiments conducted established that exosomes from BDNF-overexpressing HEK293 cells improved cerebral I/R injury by concealing neuronal apoptosis. Findings gained demonstrated that BDNF is a part of preventing cerebral I/R injury due to exosome mediation by regulating the cellular internal environment and inhibiting apoptosis.

Receptors, Channel Proteins, and Enzymes Involved in Microglia-mediated Neuroinflammation and Treatments by Targeting Microglia in Ischemic Stroke

Stroke is the largest contributor to global neurological disability-adjusted life-years, posing a huge economic and social burden to the world. Though pharmacological recanalization with recombinant tissue plasminogen activator and mechanical thrombectomy have greatly improved the prognosis of patients with ischemic stroke, clinically, there is still no effective treatment for the secondary injury caused by cerebral ischemia. In recent years, more and more evidences show that neuroinflammation plays a pivotal role in the pathogenesis and progression of ischemic cerebral injury. Microglia are brain resident innate immune cells and act the role peripheral macrophages. They play critical roles in mediating neuroinflammation after ischemic stroke. Microglia-mediated neuroinflammation is not an isolated process and has complex relationships with other pathophysiological processes as oxidative/nitrative stress, excitotoxicity, necrosis, apoptosis, pyroptosis, autophagy, and adaptive immune response. Upon activation, microglia differentially express various receptors, channel proteins, and enzymes involved in promoting or inhibiting the inflammatory processes, making them the targets of intervention for ischemic stroke. To inhibit microglia-related neuroinflammation and promote neurological recovery after ischemic stroke, numerous biochemical agents, cellular therapies, and physical methods have been demonstrated to have therapeutic potentials. Though accumulating experimental evidences have demonstrated that targeting microglia is a promising approach in the treatment of ischemic stroke, the clinical progress is slow. Till now, no clinical study could provide convincing evidence that any biochemical or physical therapies could exert neuroprotective effect by specifically targeting microglia following ischemic stroke.

REMOTE Ischemic Perconditioning Among Acute Ischemic Stroke Patients in Catalonia: REMOTE-CAT PROJECT

Rationale: Remote ischemic perconditioning during cerebral ischemia (RIPerC) refers to the application of brief episodes of transient limb ischemia commonly to a limb, it represents a new safe, simple and low-cost paradigm in neuroprotection.

Aim and/or Hypothesis: To evaluate the effects of RIPerC on acute ischemic stroke (AIS) patients, applied in the ambulance, to improve functional outcomes compared with standard of care.

Sample Size Estimates: A sample size of 286 patients in each arm achieves 80% power to detect treatment differences of 14% in the outcome, using a two-sided binomial test at significance level of 0.05, assuming that 40% of the control patients will experience good outcome and an initial misdiagnosis rate of 29%.

Methods and Design: We aim to conduct a multicentre study of pre-hospital RIPerC application in AIS patients. A total of 572 adult patients diagnosed of suspected clinical stroke within 8 h of symptom onset and clinical deficit >0 according to prehospital rapid arterial occlusion evaluation (RACE) scale score will be randomized, in blocks of size 4, to RIPerC or sham. Patients will be stratified by RACE score scale. RIPerC will be started in the ambulance before hospital admission and continued in the hospital if necessary. It will consist of five cycles of electronic tourniquet inflation and deflation (5 min each). The cuff pressure for RIPerC will be 200 mmHg during inflation. Sham will only simulate vibration of the device.

Study Outcome(s): The primary outcome will be the difference in the proportion of patients with good outcomes as defined by a mRS score of 2 or less at 90 days. Secondary outcomes to be monitored will include early neurological improvement rate, treatment related serious adverse event rates, size of the infarct volume, symptomatic intracranial hemorrhage, metabolomic and lipidomic response to RIPerC and Neuropsychological evaluation at 90 days.

Discussion: Neuroprotective therapies could not only increase the benefits of available reperfusion therapies among AIS patients but also provide an option for patients who are not candidates for these treatments. REMOTE-CAT will investigate the clinical benefit of RIC as a new neuroprotective strategy in AIS.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03375762.

The effect of remote ischemic postconditioning on autonomic function in patients with acute ischemic stroke: A Randomized Controlled Trail

OBJECTIVE

The evidence for the effect of remote ischemic postconditioning(RIpostC) on autonomic function in patients with acute ischemic stroke(AIS) is lacking and the neural mechanism underlying the protection of RIpostC remains speculative. This trial was aimed to evaluated the efficiency of RIpostC on autonomic function in AIS patients.

DESIGN

One hundred and six AIS patients were included in this prospective, randomized, placebo-controlled trial. Patients in intervention group (n = 57) received 4 cycles of alternating inflation (cuff inflation to 200 mmHg) and deflation for 5 min on healthy upper arm once a day for 30 days. The control group underwent a sham inflation and deflation cycles. Autonomic function was evaluated by heart rate variability (HRV).

RESULTS

All HRV parameters except for the ratio of low frequency to high frequency (P = 0.101) increased significantly with time (P < 0.001) in the two groups. The value of standard deviation of all normal R-R intervals(SDNN) and high frequency at day7 and day30 and the value of the percent of difference between adjacent normal R-R intervals (pNN50) at day 30 in RIpostC group was significantly higher than that of the sham-RIpostC group(P < 0.05). A significant time-by-group interaction was observed in SDNN、pNN50、and high frequency over time between two groups (P < 0.05).

CONCLUSIONS

30-day RIpostC could improve autonomic function in AIS patients through the enhancement of the total autonomic nerve activity and vagus nerve activity. The mechanism of RIpostC mediating autonomic function needs to be further investigated.

Induced neuroprotection by remote ischemic perconditioning as a new paradigm in ischemic stroke at the acute phase, a systematic review

BACKGROUND

Remote ischemic conditioning during cerebral ischemia (remote ischemic perconditioning, RIPerC) refers to the application of several cycles of brief ischemia and reperfusion (I/R) commonly to a limb, and it represents a new paradigm in neuroprotection with multiple mechanisms of action in ischemic stroke (IS) patients during acute phase. Some clinical trials just finished, and a few others are still ongoing; gather the current knowledge and pull it down to influence the present and future studies was the goal of this paper.

METHODS

A systematic review of published research papers and/or registered clinical trials since 2000 was performed.

RESULTS

Nineteen studies were identified and only four studies were completed. All of them have demonstrated that RIPerC is safe, feasible and well tolerated in IS patients. However, a high heterogeneity of clinical trial characteristics was observed: five (26.3%) randomized clinical trials (RCTs) included only thrombolytic-treated patients, three (15.8%) RCTs only thrombectomy-treated patients, and five (26.3%) RCTs required radiological confirmation of IS. Temporal inclusion criteria vary from 4 h to 48 h. Most of the clinical trials used 4 cycles of RIPerC in the upper non-affected limb. Interestingly, only three (16.7%) RCTs applied RIPerC during the transportation in the ambulance. Neuroimaging outputs were the main endpoints when endovascular therapy was applied; functional outcome is also the main endpoint in large-medium size studies.

CONCLUSIONS

This review summarizes the completed and ongoing clinical trials on RIPerC in IS patients, where RIPerC has been used alone or in combination with recanalization therapies. Ongoing clinical trials will provide new information on the best RIPerC intervention strategy and potentially improve the functional outcome of IS patients; definition of new RIPerC strategies would ideally aim at enhancing tissue preservation, promoting neurological recovery, and stratify patients to improve treatment feasibility.

Remote ischemic conditioning combined with intravenous thrombolysis for acute ischemic stroke

Objective

The objective of this study was to investigate the safety and efficacy of remote ischemic conditioning (RIC) combined with intravenous thrombolysis (IVT) in the treatment of acute ischemic stroke (AIS).

Methods

Patients with AIS who underwent IVT were enrolled and 1:1 randomized to the RIC group and sham‐RIC group in this study. RIC (or sham‐RIC) was performed twice within 6–24 h of IVT. The subjects in the two groups were followed up for 90 days. The safety outcome included the ratio of hemorrhagic transformation (HT), adverse events during the follow‐up, blood pressure within the first 24 h after IVT, and laboratory tests 24 h after IVT. The efficacy outcome included the modified Rankin Scale (mRS) score, National Institute of Health Stroke Scale (NIHSS) score during the follow‐up, and level of high‐sensitivity C‐reactive protein (hs‐CRP) tested 24 h after IVT.

Results

Forty‐nine patients (24 in the RIC group and 25 in the sham‐RIC group) were recruited. No significant difference was observed in the ratio of HT, adverse events, blood pressure, coagulation function or liver function between groups. In addition, there was no significant difference in mRS score and NIHSS score during the follow‐up between groups. However, patients in the RIC group exhibited a significant lower level of hs‐CRP compared with the control group (P = 0.048).

Interpretation

RIC combined with IVT is safe in the treatment of AIS. The neuroprotective and anti‐inflammatory effects of this therapy warrant further study on a larger scale.

RIPC provides neuroprotection against ischemic stroke by suppressing apoptosis via the mitochondrial pathway

Ischemic stroke is a common disease with high morbidity and mortality. Remote ischemic preconditioning (RIPC) can stimulate endogenous protection mechanisms by inducing ischemic tolerance to reduce subsequent damage caused by severe or fatal ischemia to non-ischemic organs. This study was designed to assess the therapeutic properties of RIPC in ischemic stroke and to elucidate their underlying mechanisms. Neurobehavioral function was evaluated with the modified neurological severity score (mNSS) test and gait analysis. PET/CT was used to detect the ischemic volume and level of glucose metabolism. The protein levels of cytochrome c oxidase-IV (COX-IV) and heat shock protein 60 (HSP60) were tested by Western blotting. TUNEL and immunofluorescence staining were used to analyze apoptosis and to observe the nuclear translocation and colocalization of apoptosis-inducing factor (AIF) and endonuclease G (EndoG) in apoptotic cells. Transmission electron microscopy (TEM) was used to detect mitochondrial-derived vesicle (MDV) production and to assess mitochondrial ultrastructure. The experimental results showed that RIPC exerted significant neuroprotective effects, as indicated by improvements in neurological dysfunction, reductions in ischemic volume, increases in glucose metabolism, inhibition of apoptosis, decreased nuclear translocation of AIF and EndoG from mitochondria and improved MDV formation. In conclusion, RIPC alleviates ischemia/reperfusion injury after ischemic stroke by inhibiting apoptosis via the endogenous mitochondrial pathway.

Effect of remote ischaemic preconditioning on walking in people with multiple sclerosis: double-blind randomised controlled trial

Background

Remote ischaemic preconditioning (RIPC) is the exposure of body parts to brief periods of circulatory occlusion and reperfusion. Recent studies have also shown that RIPC can improve exercise performance in healthy individuals.

Objective

This study aimed to assess the effect of RIPC on walking in people with multiple sclerosis (MS).

Methods

This was a double-blind randomised controlled clinical trial. We used three cycles of RIPC delivered by occluding the upper arm with a blood pressure (BP) cuff inflated to a pressure of 30 mm Hg above the systolic BP. In patients in the sham intervention group, the BP cuff was inflated only to 30 mm Hg below diastolic BP. Outcome measures included the Six-Minute Walk Test (6MWT), gait speed, the Borg rate of perceived exertion (RPE) scale, the tolerability of the RIPC using a Numerical Rating Scale for discomfort from 0 to 10, and adverse events. We identified responders meeting the minimal clinically important difference (MCID) established in the literature in each group.

Results

Seventy-five participants completed the study (RIPC: 38 and Sham: 37). The distance walked during the 6MWT improved by 1.9% in the sham group and 5.7% in the RIPC group (p=0.012). The number of responders meeting MCID criteria in the RIPC group was significantly greater compared with the sham intervention group. No serious adverse events occurred.

Conclusion

Single cycle of RIPC resulted in immediate improvement in walking distances during 6MWT in people with MS.

Trial registration numbers

NCT03153553

Effects of Remote Ischemic Conditioning on Cerebral Hemodynamics in Ischemic Stroke

Ischemic stroke is one of the most common cerebrovascular diseases and is the leading cause of disability all over the world. It is well known that cerebral blood flow (CBF) is disturbed or even disrupted when ischemic stroke happens. The imbalance between demand and shortage of blood supply makes ischemic stroke take place or worsen. The search for treatments that can preserve CBF, especially during the acute phase of ischemic stroke, has become a research hotspot. Animal and clinical experiments have proven that remote ischemic conditioning (RIC) is a beneficial therapeutic strategy for the treatment of ischemic stroke. However, the mechanism by which RIC affects CBF has not been fully understood. This review aims to discuss several possible mechanisms of RIC on the cerebral hemodynamics in ischemic stroke, such as the improvement of cardiac function and collateral circulation of cerebral vessels, the protection of neurovascular units, the formation of gas molecules, the effect on the function of vascular endothelial cells and the nervous system. RIC has the potential to become a therapeutic treatment to improve CBF in ischemic stroke. Future studies are needed to highlight our understanding of RIC as well as accelerate its clinical translation.

Remote Ischemic Conditioning After Stroke Trial 2: A Phase IIb Randomized Controlled Trial in Hyperacute Stroke

Background Repeated episodes of limb ischemia and reperfusion (remote ischemic conditioning [RIC]) may protect the brain from ischemic reperfusion injury. Methods and Results We performed a phase IIb blinded dose-escalation sham-controlled trial in patients with hyperacute stroke, randomized 1:1 to receive RIC (four 5-minute cycles) or sham to the nonparetic upper limb, in 3 blocks of increasing dose, starting within 6 hours of ictus. The primary outcome was trial feasibility (recruitment, attrition). Secondary outcomes included adherence, tolerability, safety (serious adverse events), plasma biomarkers at days 1 and 4 (S100-ß protein, matrix metalloproteinase-9, and neuron-specific enolase), and functional outcome. Sixty participants were recruited from 2 centers (3 per month) with no loss to follow-up: time to randomization 4 hours 5 minutes (SD 72 minutes), age 72 years (12), men 60%, blood pressure 154/80 mm Hg (25/12), National Institutes of Health Stroke Scale 8.4 (6.9), and 55% thrombolyzed. RIC was well tolerated with adherence not differing between RIC and sham, falling in both groups on day 3 (P=0.001, repeated measures ANOVA) because of discharge or transfer. S100ß increased in the sham group (mean rise 111 pg/mL [302], P=0.041, repeated measures ANCOVA) but not the RIC group. There were no differences in matrix metalloproteinase-9, neuron-specific enolase, number with serious adverse events (RIC 10 versus sham 10, P=0.81), deaths (2 versus 4, P=0.36), or modified Rankin Scale score (2 [interquartile range 1-4], 2 [interquartile range, 1-3]; P=0.85). Conclusions RIC in hyperacute stroke is feasible when given twice daily for 2 days and appears safe in a small population with hyperacute stroke. A larger phase III trial is warranted. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02779712.