Remote Ischemic Conditioning Research Articles

P.030 Remote ischemic conditioning in acute ischemic stroke and small vessel disease – a feasibility study

Background: We tested the hypothesis that delivering remote ischemic conditioning (RIC) with an adjunct tissue reflectance sensor (TRS) device may be feasible in patients with acute ischemic stroke (AIS) and cerebral small vessel disease (cSVD). Methods: AIS patients with neurological deficits within 7 days of symptom onset were screened for moderate to severe cSVD. Eligible patients were randomized 2:1 to receive intervention RIC or sham RIC (7 days). The primary outcome measure was intervention feasibility. It was assessed as an intervention-related comfort by a 5-point Likert scale during each session (1-very uncomfortable, 5-very comfortable). The secondary outcome measure was assessment of TRS derived dermal blood concentration and blood oxygenation changes during RIC. Results: Forty-seven (32 intervention, 15 sham) patients were enrolled at a median (IQR) 39.7 (25-64) hours after symptom onset, with mean±SD age of 75±12 years, 22 (46.8%) were females and median baseline NIHSS of 5(3-7). The Likert scale was 3.5 (3-4) in the intervention group and 4 (4-5) in the sham group. The TRS derived blood concentration and blood oxygenation changes were proportionate in the intervention arm and absent in the sham arm. Conclusions: RIC treatment with TRS is feasible in patients with AIS+cSVD. The efficacy of RIC needs further assessment.

Transcriptomic analysis of the effect of remote ischaemic conditioning in an animal model of necrotising enterocolitis

Necrotising enterocolitis (NEC) has a complex pathophysiology but the common end-point is ischaemia reperfusion injury (IRI) and intestinal necrosis. We have previously reported that RIC significantly reduces the intestinal injury in a rat model of NEC. Here we describe the changes in intestinal mRNA occurring in the intestine of animals exposed to IRI, both with and without RIC. Related rat-pups were randomly assigned to four groups: SHAM, IRI only, RIC only and RIC + IRI. IRI animals, underwent 40 min of intestinal ischaemia, and 90 min of reperfusion. Animals that underwent RIC had three cycles of 5 min of alternating ischaemia/reperfusion by means of a ligature applied to the hind limb. Samples from the terminal ileum were immediately stored in RNA-preserving media for later next generation sequencing and transciptome analysis using R v 3.6.1. Differential expression testing showed that 868 genes differentially expressed in animals exposed to RIC alone compared to SHAM and 135 in the IRI and RIC group compared to IRI alone. Comparison between these two sets showed that 25 genes were differentially expressed in both groups. Pro-inflammatory molecules: NF-ĸβ2, Cxcl1, SOD2 and Map3k8 all show reduced expression in response to RIC. Targeted gene analysis revealed increased expression in PI3K which is part of the so-called RISK-pathway which is a key part of the protective mechanisms of RIC in the heart. Overall, this transcriptomic analysis shows that RIC provides a protective effect to the intestine via anti-inflammatory pathways. This could be particularly relevant to treating and preventing NEC.

Remote Ischemic Conditioning to Reduce Perihematoma Edema in Patients with Intracerebral Hemorrhage (RICOCHET): A Randomized Control Trial.

Background: Early perihematomal edema (PHE) growth is associated with worse functional outcomes at 90 days. Remote Ischemic conditioning (RIC) may reduce perihematomal inflammation if applied early to patients with intracerebral hemorrhage (ICH). We hypothesize that early RIC, delivered for seven days in patients with spontaneous ICH, may reduce PHE growth. Methods: ICH patients presenting within 6 h of symptom onset and hematoma volume < 60 milliliters (mL) were randomized to an RIC + standard care or standard care (SC) group. The primary outcome measure was calculated edema extension distance (EED), with the cm assessed on day seven. Results: Sixty patients were randomized with a mean ± SD age of 57.5 ± 10.8 years, and twenty-two (36.7%) were female. The relative baseline median PHE were similar (RIC group 0.75 (0.5-0.9) mL vs. SC group 0.91 (0.5-1.2) mL, p = 0.30). The median EEDs at baseline were similar (RIC group 0.58 (0.3-0.8) cm vs. SC group 0.51 (0.3-0.8) cm, p = 0.76). There was no difference in the median day 7 EED (RIC group 1.1 (0.6-1.2) cm vs. SC group 1 (0.9-1.2) cm, p = 0.75). Conclusions: Early RIC therapy delivered daily for seven days was feasible. However, no decrease in EED was noted with the intervention.

Mitochondrial Kinase Signaling for Cardioprotection.

Myocardial ischemia/reperfusion injury is reduced by cardioprotective adaptations such as local or remote ischemic conditioning. The cardioprotective stimuli activate signaling cascades, which converge on mitochondria and maintain the function of the organelles, which is critical for cell survival. The signaling cascades include not only extracellular molecules that activate sarcolemmal receptor-dependent or -independent protein kinases that signal at the plasma membrane or in the cytosol, but also involve kinases, which are located to or within mitochondria, phosphorylate mitochondrial target proteins, and thereby modify, e.g., respiration, the generation of reactive oxygen species, calcium handling, mitochondrial dynamics, mitophagy, or apoptosis. In the present review, we give a personal and opinionated overview of selected protein kinases, localized to/within myocardial mitochondria, and summarize the available data on their role in myocardial ischemia/reperfusion injury and protection from it. We highlight the regulation of mitochondrial function by these mitochondrial protein kinases.

Remote Ischemic Postconditioning in Case of Traumatic Brain Injury: a Review of Experimental and Clinical Studies

Relevance Traumatic brain injury (TBI) remains one of the leading causes of morbidity and mortality worldwide. Despite advances in treatment based on understanding of the mechanisms of brain injury after TBI, there is a clear need for new therapeutic strategies. Remote ischemic postconditioning (RIPostC) can be considered as a non-pharmacological technique to reduce secondary brain damage and improve clinical outcomes in patients with TBI.Aim of study Raising awareness of emergency physicians, neurosurgeons, neurologists, neurophysiologists about the possible use of the concept of RIPostC in patients with TBI.Material and methods To achieve this goal, the Results of clinical and experimental studies of the use of RIPostC after TBI were analyzed. Literature search was carried out in electronic search systems PubMed (https://pubmed.ncbi.nlm.nih.gov), eLibrary (https://elibrary.ru) using the keywords: “traumatic brain injury”, “remote ischemic conditioning”. A systematic search and selection of publications was performed in January–February 2023. The results of the review included patients with an established diagnosis of traumatic brain injury, followed by the use of RIPostC and animals with experimental modeling of TBI in various ways, followed by RIPostC.Conclusion The totality of data suggests that the use of the concept of RIPostC as a non-invasive protective technique in the provision of emergency care for patients with TBI may contribute to limiting secondary brain damage. However, the underlying neuroprotective processes are quite complex and need further study. Establishing the relationship of humoral, neurogenic and inflammatory reactions in response to the use of RIPostC in TBI will contribute to understanding the mechanisms of emerging neuroprotection, help ease the course of the disease and improve the clinical outcome.

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

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. 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). 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. 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.

Is There a Mitochondrial Protection via Remote Ischemic Conditioning in Settings of Anticancer Therapy Cardiotoxicity?

To provide an overview of (a) protective effects on mitochondria induced by remote ischemic conditioning (RIC) and (b) mitochondrial damage caused by anticancer therapy. We then discuss the available results of studies on mitochondrial protection via RIC in anticancer therapy-induced cardiotoxicity. In three experimental studies in healthy mice and pigs, there was a RIC-mediated protection against anthracycline-induced cardiotoxicity and there was some evidence of improved mitochondrial function with RIC. The RIC-mediated protection was not confirmed in the two available studies in cancer patients. In adult cancer patients, RIC was associated with an adverse outcome. There are no data on mitochondrial function in cancer patients. Studies in tumor-bearing animals are needed to determine whether RIC does not interfere with the anticancer properties of the drugs and whether RIC actually improves mitochondrial function, ultimately resulting in improved cardiac function.

Bilateral remote ischemic conditioning in children: A two-center, double-blind, randomized controlled trial in young children undergoing cardiac surgery

ObjectiveThe study objective was to determine whether adequately delivered bilateral remote ischemic preconditioning is cardioprotective in young children undergoing surgery for 2 common congenital heart defects with or without cyanosis. MethodsWe performed a prospective, double-blind, randomized controlled trial at 2 centers in the United Kingdom. Children aged 3 to 36 months undergoing tetralogy of Fallot repair or ventricular septal defect closure were randomized 1:1 to receive bilateral preconditioning or sham intervention. Participants were followed up until hospital discharge or 30 days. The primary outcome was area under the curve for high-sensitivity troponin-T in the first 24 hours after surgery, analyzed by intention-to-treat. Right atrial biopsies were obtained in selected participants. ResultsBetween October 2016 and December 2020, 120 eligible children were randomized to receive bilateral preconditioning (n = 60) or sham intervention (n = 60). The primary outcome, area under the curve for high-sensitivity troponin-T, was higher in the preconditioning group (mean: 70.0 ± 50.9 μg/L/h, n = 56) than in controls (mean: 55.6 ± 30.1 μg/L/h, n = 58) (mean difference, 13.2 μg/L/h; 95% CI, 0.5-25.8; P = .04). Subgroup analyses did not show a differential treatment effect by oxygen saturations (pinteraction = .25), but there was evidence of a differential effect by underlying defect (pinteraction = .04). Secondary outcomes and myocardial metabolism, quantified in atrial biopsies, were not different between randomized groups. ConclusionsBilateral remote ischemic preconditioning does not attenuate myocardial injury in children undergoing surgical repair for congenital heart defects, and there was evidence of potential harm in unstented tetralogy of Fallot. The routine use of remote ischemic preconditioning cannot be recommended for myocardial protection during pediatric cardiac surgery.

Targeting blood brain barrier-Remote ischemic conditioning alleviates cognitive impairment in female APP/PS1 rats.

Alzheimer's disease (AD) is a significant global health concern, and it is crucial that we find effective methods to prevent or slow down AD progression. Recent studies have highlighted the essential role of blood vessels in clearing Aβ, a protein that contributes to AD. Scientists are exploring blood biomarkers as a potential tool for future AD diagnosis. One promising method that may help prevent AD is remote ischemic conditioning (RIC). RIC involves using sub-lethal ischemic-reperfusion cycles on limbs. However, a comprehensive understanding of how RIC can prevent AD and its long-term effectiveness is still lacking. Further research is essential to fully comprehend the potential benefits of RIC in preventing AD. Female wild-type (WT) and APP/PS1 transgenic rats, aged 12 months, underwent ovariectomy and were subsequently assigned to WT, APP/PS1, and APP/PS1 + RIC groups. RIC was conducted five times a week for 4 weeks. The rats' depressive and cognitive behaviors were evaluated using force swimming, open-field tests, novel objective recognition, elevated plus maze, and Barnes maze tests. Evaluation of the neurovascular unit (NVU), synapses, vasculature, astrocytes, and microglia was conducted using immunofluorescence staining (IF), Western blot (WB), and transmission electron microscopy (TEM). Additionally, the cerebro-vasculature was examined using micro-CT, and cerebral blood flow (CBF) was measured using Speckle Doppler. Blood-brain barrier (BBB) permeability was determined by measuring the Evans blue leakage. Finally, Aβ levels in the rat frontal cortex were measured using WB, ELISA, or IF staining. RIC enhanced memory-related protein expression and rescued depressive-like behavior and cognitive decline in APP/PS1 transgenic rats. Additionally, the intervention protected NVU in the rat frontal cortex, as evidenced by (1) increased expression of TJ (tight junction) proteins, pericyte marker PDGFRβ, and glucose transporter 1 (GLUT1), as well as decreased VCAM1; (2) mitigation of ultrastructure impairment in neuron, cerebral vascular, and astrocyte; (3) upregulation of A2 astrocyte phenotype markers and downregulation of A1 phenotype markers, indicating a shift toward a healthier phenotype. Correspondingly, RIC intervention alleviated neuroinflammation, as evidenced by the decreased Iba1 level, a microglia marker. Meanwhile, RIC intervention elevated CBF in frontal cortex of the rats. Notably, RIC intervention effectively suppressed Aβ toxicity, as demonstrated by the enhancement of α-secretase and attenuation of β-secretase (BACE1) and γ- secretase and Aβ1-42 and Aβ1-40 levels as well. Chronic RIC intervention exerts vascular and neuroprotective roles, suggesting that RIC could be a promising therapeutic strategy targeting the BBB and NVU during AD development.

Abstract 61: The Effect of Remote Ischemic Conditioning in Stroke Subtypes: A Subgroup Analysis From the RESIST Trial

Introduction: Remote ischemic conditioning (RIC) is a simple and non-invasive procedure that has proved safe and feasible in numerous smaller clinical trials. Still, mixed results have been found in recent large randomized controlled trials. Here we present a predefined subgroup analysis of the RESIST trial on the effect of RIC in subgroups of acute ischemic stroke (AIS) and whether this effect is modified by adherence to RIC. Methods: The subgroups were defined as large artery atherosclerotic disease (LAA), small vessel disease (SVD), cardioembolic, and unknown/other/multiple/rare, and were based on ICD-10 discharge diagnoses assigned by the treating physician to define stroke etiology. Acceptable treatment adherence was defined as at least 80% received out of planned cycles. The outcome analysis used the entire range (‘shift analysis’) of the 90-day modified Rankin Scale score (ordinal logistic regression). ClinicalTrials.gov:NCT03481777. Results: A total of 902 patients were included in the target population group, 466 in the sham group, and 436 in the RIC group. RIC did not significantly improve functional outcome in adherent patients with LAA, cardioembolic or multiple/unknown etiologies. In SVD patients (n=94), with good treatment adherence, RIC treatment was associated with a significantly improved 90-day functional outcome, unadjusted OR (95% CI): 2.47 (1.01-6.02), p= 0.047. In patients with SVD, 4 patients (8%) in the RIC group compared to 0 patients in the sham group had atrial fibrillation (AF), p=0.050. The association remained significant after adjusting for AF, adjusted OR (95% CI): 2.64 (1.07-6.54), p= 0.035. Conclusions: In patients with AIS due to SVD, who had good treatment adherence, RIC treatment was associated with improved functional outcome at 90 days. These results are encouraging but should only be hypothesis-generating for future studies.

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

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

Randomized Secondary Prevention Trials in Participants With Symptomatic Intracranial Atherosclerotic Stenosis.

Intracranial atherosclerotic stenosis is a prevalent cause of ischemic stroke worldwide. Its association with silent cerebral infarcts and its contribution to cognitive impairment and dementia emphasize the critical need for disease prevention and effective management strategies. Despite extensive research on secondary stroke prevention treatment over the past several decades, intracranial atherosclerotic stenosis continues to exhibit a notably higher recurrent stroke rate compared with other causes. This review focuses on randomized secondary prevention trials involving antithrombotic therapy, endovascular treatment, open surgical therapy, and remote ischemic conditioning. It aims to provide an insightful overview of the major findings from each trial and their implications for future research efforts.

Abstract TP285: Chronic Remote Ischemic Conditioning (C-RIC) and Physical Exercise Attenuate NLRP3 Inflammasome Activation Induced by Chronic Cerebral Hypoperfusion in the BCAS Mouse Model of VCID

Background and Purpose: Inflammation plays a significant role in acute and chronic cerebral ischemia. The bilateral carotid artery stenosis (BCAS)-induced chronic cerebral hypoperfusion activates the NLRP inflammasome in brain tissue. We aimed to determine if C-RIC and physical exercise (EXR) attenuated the increase in the NLRP3 inflammasome and related cytokines in the BCAS model. Methods: Microcoil-induced BCAS was used for chronic hypoperfusion, a model for VCID. Middle-young (5 months old) and old-aged (14 months old) C57Bl/6 mice were randomly assigned to Sham, BCAS, and BCAS+EXR (four weeks treadmill exercise) for middle-young mice and to Sham, BCAS, and BCAS+RIC (four months C-RIC treatment) for old-aged mice of both sexes. qPCR was run for NLRP3, TNFa, IL-1B, IL-6, IL-10, ICAM1, VCAM1 in brain tissue.Biochemical assays and histopathological staining of NLRP3 were also assessed on the brain tissues. Results: Four weeks of exercise in middle-aged mice and 4 months of C-RIC in aged RIC groups attenuated the increased NLRP3, cytokines (IL-1B, IL-6, IL-10, TNFα), and inflammatory markers (ICAM-1 &amp; VCAM-1) induced by BCAS in middle-aged (exercise) and aged mice (CRIC). Western blot and immunohistopathological studies also attenuated the increased NLRP3 expression after physical exercise and C-RIC treatment. Conclusions: C-RIC and Physical exercise attenuated the increase of NLRP3 inflammasome and cytokines (IL-1B, IL-6, IL-10, TNFα) induced by chronic cerebral hypoperfusion in the BCAS mouse model of VCID. This may be an important mechanism of action of physical exercise and C-RIC in VCID.

Dyslipidemia and Efficacy of Remote Ischemic Conditioning in Acute Moderate Ischemic Stroke: A Post Hoc Analysis of the RICAMIS Study.

Ischemic conditioning-induced cardioprotection was attenuated by dyslipidemia in some animal and clinical studies, which is not investigated in patients with stroke. We conducted a post hoc analysis of the RICAMIS (Remote Ischemic Conditioning for Acute Moderate Ischemic Stroke) trial to investigate the association of dyslipidemia on admission with the efficacy of remote ischemic conditioning (RIC). In this analysis, eligible patients were divided into dyslipidemia and normal-lipid groups according to the levels of 4 blood lipid profiles (total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol), which were further subdivided into RIC and control subgroups. We analyzed the differences in functional outcome between RIC and control subgroups in dyslipidemia and normal-lipid patients, respectively, and the interaction effects of RIC treatment with blood lipid levels were evaluated. Among 1776 patients from intention-to-treat analysis, 1419 patients with data of blood lipid profiles were included in the final analysis. A significantly higher proportion of modified Rankin Scale score 0 to 1 was identified in the RIC versus control subgroup across the normal-total cholesterol group (69.9% versus 63.5%; P=0.04), normal-triglycerides group (68.1% versus 60.5%; P=0.016), high-low-density lipoprotein cholesterol group (65.7% versus 57.7%; P=0.025), and normal-high-density lipoprotein cholesterol group (68.3% versus 60.5%; P=0.005). Similar statistical trends were found in the high-total cholesterol group (62.8% versus 55.5%; P=0.059), high-triglycerides group (67.8% versus 60.1%; P=0.099), normal-low-density lipoprotein cholesterol group (69.8% versus 63.7%; P=0.105), but no statistical significance was found in the low-high-density lipoprotein cholesterol group (63.4% versus 61%; P=0.705). Furthermore, no significant interaction effect of RIC intervention by blood lipid profiles was found. Similar results were obtained for lipids as continuous variables. Blood lipids on admission was not associated with the neuroprotective effect of RIC.

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.

Nephroprotective effect of remote ischemic conditioning on type 2 diabetic rats.

Diabetic nephropathy is one of the main causes of kidney failure in the end stage of diabetes worldwide. The present study was conducted with the aim of using the remote ischemic conditioning (RIC) method to prevent diabetic nephropathy. Diabetes was induced by high-fat diet (60%) and streptozotocin injection (35 mg/kg) in rats. RIC was performed by tightening a tourniquet around the upper thigh and releasing it for three cycles of 5 min of ischemia and 5 min of reperfusion daily for an 8-week duration. At the end of the experiment, serum and urine parameters were examined. Anti-oxidant enzymes and lipid peroxidation levels in the kidney were also determined along with histological examination. The expression levels of tumor necrosis factor-alpha and transforming growth factor beta genes were also evaluated. Glucose, cholesterol, triglyceride, and HbA1c concentrations were not significantly reduced in the RIC group. On the other hand, serum creatinine, urea, and albumin levels decreased and increased in urine. Anti-oxidant enzymes did improve in the kidney significantly and the expression of tumor necrosis factor-alpha and transforming growth factor beta genes decreased significantly. Histopathological examination also showed that necrosis, epithelial damage, and leukocyte infiltration increased in the diabetic group and improved in the treatment group. The results of biochemical analysis, and enzymatic and histological examinations showed that although RIC could not reduce blood glucose and lipids, nevertheless it may delay the progression of diabetic nephropathy due to the presence of anti-inflammatory and anti-oxidant activities.

Reperfusion Injury: How Can We Reduce It by Pre-, Per-, and Postconditioning.

While early coronary reperfusion via primary percutaneous coronary intervention (pPCI) is established as the most efficacious therapy for minimizing infarct size (IS) in acute ST-elevation myocardial infarction (STEMI), the restoration of blood flow also introduces myocardial ischemia-reperfusion injury (IRI), leading to cardiomyocyte death. Among diverse methods, ischemic conditioning (IC), achieved through repetitive cycles of ischemia and reperfusion, has emerged as the most promising method to mitigate IRI. IC can be performed by applying the protective stimulus directly to the affected myocardium or indirectly to non-affected tissue, which is known as remote ischemic conditioning (RIC). In clinical practice, RIC is often applied by serial inflations and deflations of a blood pressure cuff on a limb. Despite encouraging preclinical studies, as well as clinical studies demonstrating reductions in enzymatic IS and myocardial injury on imaging, the observed impact on clinical outcome has been disappointing so far. Nevertheless, previous studies indicate a potential benefit of IC in high-risk STEMI patients. Additional research is needed to evaluate the impact of IC in such high-risk cohorts. The objective of this review is to summarize the pathophysiological background and preclinical and clinical data of IRI reduction by IC.

The Infarct-Limiting Effect of Remote Ischemic Conditioning in Rats Is Not Affected by Aspirin.

Remote ischemic conditioning (RIC)has been shown to be a powerful cardioprotective therapy in animal models. However, a protective effect in patients presenting with acute myocardial infarction has failed to be confirmed. A recent pre-clinical study reported that aspirin which is routinely given to patients undergoing reperfusion therapy blocked the infarct-limiting effect of ischemic postconditioning. The present study was designed to test whether aspirin could also be blocking the infarct-limiting effect of RIC. This was investigated in vivo using male Sprague Dawley rats (n = 5 to 6 per group) subjected to either 30 min of regional myocardial ischemia, followed by 120-min reperfusion, or additionally to a RIC protocol initiated after 20-min myocardial ischemia. The RIC protocol included four cycles of 5-min hind limb ischemia interspersed with 5-min reperfusion. Intravenous aspirin (30 mg/kg) or vehicle (saline) was administered after 15-min myocardial ischemia. RIC significantly reduced infarct size (IS) normalized to the area at risk, by 47%. Aspirin administration did not affect IS nor did it attenuate the infarct-limiting effect of RIC. Aspirin administration in the setting of myocardial infarction is not likely to interfere with the cardioprotective effect of RIC.

Changes in excitatory amino acid transporters in response to remote ischaemic preconditioning and glutamate excitotoxicity

The successful implementation of remote ischaemic conditioning as a clinical neuroprotective strategy requires a thorough understanding of its basic principles, which can be modified for each patient. The mechanisms of glutamate homeostasis appear to be a key component. In the current study, we focused on the brain-to-blood glutamate shift mediated by glutamate transporters (excitatory amino acid transports [EAATs]) and the effect of remote ischaemic preconditioning (RIPC) as a mediator of ischaemic tolerance. We used model mimicking ischaemia-mediated excitotoxicity (intracerebroventricular administration of glutamate) to avoid the indirect effect of ischaemia-triggered mechanisms. We found quantitative changes in EAAT2 and EAAT3 and altered membrane trafficking of EAAT1 on the cells of the choroid plexus. These changes could underlie the beneficial effects of ischaemic tolerance. There was reduced oxidative stress and increased glutathione level after RIPC treatment. Moreover, we determined the stimulus-specific response on EAATs. While glutamate overdose stimulated EAAT2 and EAAT3 overexpression, RIPC induced membrane trafficking of EAAT1 and EAAT2 rather than a change in their expression. Taken together, mechanisms related to glutamate homeostasis, especially EAAT-mediated transport, represents a powerful tool of ischaemic tolerance and allow a certain amount of flexibility based on the stimulus used.

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.