Jacopo Mariani

BACKGROUND: Remote ischemic conditioning (RIC) has shown neuroprotective potential in preclinical stroke models. In patients with acute ischemic stroke, trials report heterogeneous results, supporting ongoing debate about clinical efficacy, especially in those ineligible for recanalization. This trial assessed RIC benefit in this population and evaluated HSP27 (heat shock protein 27) and HIF-1α (hypoxia-inducible factor 1-alpha) as biomarkers of RIC-related biological activity. METHODS: This was a multicenter, phase II, proof-of-concept, block-randomized, controlled, parallel-arm, PROBE (Prospective Randomized Open Blinded End Point)-designed clinical trial. Patients with acute ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score of 5–25) who were ineligible for recanalization therapies were randomized 1:1 within 9 hours of symptom onset to RIC (4 5-minute cycles of upper-arm ischemia/reperfusion) plus standard medical therapy or standard therapy alone. The primary outcome was the percentage change in NIHSS score at 72 hours. Secondary outcomes included NIHSS score changes at 24 and 48 hours, 90-day modified Rankin Scale, tolerability, and changes in plasma HSP27 and HIF-1α concentrations from 24 to 72 hours. RESULTS: Eighty patients (40 per group) were enrolled across 4 centers from August 2021 to March 2024. Although slightly in favor of RIC treatment, median NIHSS score percentage change at 72 hours did not differ between the RIC and control groups (23.6% versus 29.9%; adjusted coefficient, −3.8 [95% CI, −19.7 to 12.1]; P =0.635). No significant differences in NIHSS score percentage change were observed at 24 or 48 hours. Ninety-day poor functional outcome (modified Rankin Scale score, 3–6) was similar between groups (57.5% versus 65.0%; adjusted odds ratio, 0.79 [95% CI, 0.21–2.97]; P =0.732). RIC was completed by 97.5% of patients with minimal treatment-related discomfort. No major adverse events occurred. No between-group differences were detected in HIF-1α or HSP27 changes from 24 to 72 hours. CONCLUSIONS: In patients with acute ischemic stroke ineligible for recanalization therapies, early RIC was safe, feasible, and well tolerated but did not improve neurological outcomes or modify HIF-1α and HSP27 levels. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04400981.

BACKGROUND: Basic science studies have reported remote ischemic conditioning (RIC) as neuroprotective in acute ischemic stroke, although clinical evidence remains conflicting. The TRICS BASIC study (Multicenter Translational Trial of Remote Ischemic Conditioning in Acute Ischemic Stroke) investigated the efficacy and safety of RIC in experimental ischemic stroke using a rigorous clinical trial methodology. METHODS: Multicenter, multispecies, parallel group, randomized, controlled, preclinical trial of transient femoral artery clipping to induce RIC in female and male rats and mice subjected to transient endovascular occlusion of the middle cerebral artery. Animals were randomized to receive RIC, or sham surgery, after reperfusion. The primary end point was a good functional outcome at 48 hours, assessed using a composite functional neuroscore. Secondary end points were infarct volume at 48 hours and safety, assessed using a standardized health report at 24 and 48 hours. Preenrollment harmonization, centralized monitoring, allocation concealment, blinded outcome assessment, and intention-to-treat analysis were applied. RESULTS: The trial enrolled 164 rodents (82 mice and 82 rats) of both sexes (53% females), across 7 laboratories. A greater proportion of RIC-treated rodents achieved a favorable functional outcome compared with controls, at 48 hours postischemia (55% versus 36%; odds ratio, 2.2 [95% CI, 1.23–4.4]; P =0.009). RIC was associated with a small reduction in infarct volume (standardized mean difference, −0.38 [95% CI, −0.70 to −0.05]; P =0.024). Health monitoring indicated no major safety concerns, and postoperative analgesia requirements were lower in RIC-treated mice. CONCLUSIONS: Surgically induced RIC provided a modest but evident neuroprotective effect in experimental ischemic stroke, underscoring the potential of this strategy as an adjunctive treatment in stroke care. The findings of the TRICS BASIC study highlighted the importance of multicenter preclinical trials in addressing variability and enhancing translational validity. REGISTRATION: URL: https://www.preclinicaltrials.eu ; Unique identifier: PCTE0000177.

We investigated the therapeutic effect of head down positioning at −15° (head down tilt; HDT15) on cerebral collateral flow and infarct growth in a rat model of large vessel occlusion (LVO) stroke, using multi-modal MRI. Twenty-eight Wistar rats were randomly assigned to HDT15 or flat position for 60 minutes, starting 30 minutes after occlusion of the middle cerebral artery, followed by reperfusion. The perfusion shift analysis, comparing post- versus pre-treatment voxel-level changes in time-to-peak perfusion maps, showed a significant increase in cerebral perfusion in the HDT15 group (common odds ratio 1.50; 95% CI 1.41-1.60; p < 0.0001), but not in the flat group (common odds ratio 0.97; 95% CI 0.92-1.03; p = 0.3503). Infarct growth at 24 hours was + 31.4% in the flat group (343 versus 250 mm ³ ; 95% CI 2.4 to 165.1; p = 0.0447) and + 15.4% in the HDT15 group (224 versus 192 mm ³ ; 95% CI -26.9 to 85.9; p = 0.2272). Our findings indicate that HDT15 acutely increases cerebral perfusion in LVO acute ischemic stroke and provides a tissue-saving effect before recanalization. Further research is needed to develop HDT15 as an emergency therapy to acutely increase collateral flow in ischemic stroke prior to recanalization therapy.

Neurological outcome after ischemic stroke depends on residual salvageable brain tissue at the time of recanalization. Head down tilt 15° (HDT15) was proven effective in reducing infarct size and improving functional outcome in rats with transient middle cerebral artery occlusion (t‐MCAO) by increasing cerebral perfusion within the ischemic penumbra. In this pooled analysis, individual animal‐level data from three experimental series were combined in a study population of 104 t‐MCAO rats (45 in HDT15 group and 59 in flat position group). Co‐primary outcomes were infarct size and functional outcome at 24 h in both groups. The secondary outcome was hemodynamic change induced by HDT15 in ischemic and non‐ischemic hemispheres in a subgroup of animals. Infarct size at 24 h was smaller in HDT15 group than in flat position group (absolute mean difference 31.69 mm³, 95% CI 9.1–54.2, Cohen's d 0.56, p = 0.006). Functional outcome at 24 h was better in HDT15 group than in flat position group (median [IQR]: 13[10–16] vs. 11), with a shift in the distribution of the neurobehavioural scores in favour of HDT15. Mean cerebral perfusion in the ischemic hemisphere was higher during HDT15 than before its application (Perfusion Unit [P.U.], mean ± SD: 52.5 ± 19.52 P.U. vs. 41.25 ± 14.54 P.U., mean of differences 13.36, 95% CI 7.5–19.18, p = 0.0002). Mean cerebral perfusion in the non‐ischemic hemisphere before and during HDT15 was unchanged (P.U., mean ± SD: 94.1 ± 33.8 P.U. vs. 100.25 ± 25.34 P.U., mean of differences 3.95, 95%, CI −1.9 to 9.6, p = 0.1576). This study confirmed that HDT15 improves the outcome in t‐MCAO rats by promoting cerebral perfusion in the ischemic territory, without disrupting hemodynamics in non‐ischemic areas.