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Background: Neutrophils play crucial roles in the inflammatory response after acute cerebral infarction (ACI). Previous studies revealed neutrophils are non-homogeneous and can be divided into at least two subtypes, pro-inflammatory and anti-inflammatory, correlated with patients' prognosis., Objective: We aimed to explore the correlation between disease severity and peripheral blood neutrophils in patients with ACI and determine whether remote ischemic postconditioning (RIPostC) exerts neuroprotective effects by regulating neutrophils., Methods: Patients ( n = 38) with acute anterior circulation cerebral infarction were assigned to conventional treatment ( n = 24; included aspirin, statins, neuro nutrition drugs, and circulation improvement drugs) or RIPostC ( n = 14; 7-day ischemia adaptation [complete ischemia of both upper extremities for 5 minutes followed by remission for 5 minutes, 5 repeated cycles, twice a day, started from the morning of the second day of admission] based on conventional treatment) groups, based on their preference. General clinical data and peripheral blood samples were taken three times, in the morning before and 3 and 7 days after treatment. Fifteen adults with non-acute cerebral infarction matched for sex, age, and risk factors were recruited as controls; peripheral blood samples were only collected on the recruitment day. We used flow cytometry to detect the percentage of neutrophils and Real-Time PCR to detect the gene expression of interleukin (IL)-1β in the peripheral blood samples., Results: The percentage of neutrophils, pro-inflammatory neutrophils (IL-1β high expression in flow cytometry), and IL-1β mRNA expression increased after ACI ( P = 0.01, P = 0.001, P < 0.001). The National Institutes of Health Stroke Scale (NIHSS) score of patients with ACI within one day of onset was positively correlated with the percentage of pro-inflammatory neutrophils ( R = 0.618, P = 0.043). Pro-inflammatory neutrophils in the RIPostC group decreased compared with those in the conventional treatment group, with the most significant difference observed on Day 7 ( P = 0.01). However, the percentage of neutrophils was not statistically different. IL-1β mRNA expression decreased, with the most significant difference on Day 3 ( P = 0.004). The NIHSS and Modified Rankin Scale scores for RIPostC decreased more significantly than for conventional treatment ( P = 0.002, P = 0.019)., Conclusion: More severe cerebral infarction was associated with a higher percentage of pro-inflammatory neutrophils. The neuroprotective effect of RIPostC may partly be exerted through gene regulation to reduce pro-inflammatory neutrophils.

Background: Perfusion-weighted magnetic resonance imaging (MRI) can evaluate collateral circulation in patients with acute cerebral infarction by reflecting hemodynamic signals in the brain. The purpose of this study was to evaluate the collateral circulation and short-term prognosis of patients with acute cerebral infarction, using perfusion-weighted MRI., Methods: The study enrolled 206 patients with acute cerebral infarction due to unilateral cerebral artery occlusion diagnosed by digital subtraction angiography (DSA) and computed tomography angiography (CTA). The relative cerebral blood volume (rCBV), relative cerebral blood flow map (rCBF), relative peak time (rTTP), and relative mean transit time (rMTT) were calculated based on the ratio of the perfusion-weighted MRI reference values of the infarcted side and the control side of the patient. According to the results of perfusion-weighted MRI, patients were divided into a high perfusion group (n=121) and a low perfusion group (n=85). The Thrombolysis in Cerebral Infarction scale proposed by Higashida et al. in 2003 (Higashida scale) was used to evaluate the establishment of collateral circulation on the day of admission and 15 days after admission. The National Institutes of Health Stroke Scale (NIHSS) score and the modified Rankin scale assessed the short-term prognosis of patients with cerebral infarction. The Spearman correlation analysis examined the correlation between the rCBV, rCBF, and NIHSS scores, and the modified Rankin scale (mRS)., Results: Compared with the patients in the low perfusion group, the rCBV and rCBF in the infarcted area of the patients in the high perfusion group were significantly increased and the rTTP and rMTT were significantly decreased. On day 15 after admission, the collateral circulation rate of the high perfusion group was significantly higher than that of the low perfusion group, and the NIHSS score and the mRS score were significantly lower than those scores of the low perfusion group. Perfusion-weighted MRI indexes, rCBV, and rCBF were negatively correlated with the NIHSS score and Rankin scale., Conclusions: Perfusion-weighted MRI can effectively evaluate the compensatory ability of collateral circulation and the prognosis of patients with acute cerebral infarction.