The Correlation Of SerumMIF,CKLF1,FKN Levelswith Acute Ischemic Stroke And The Clinical Significance

ObjectWith improvements in living standards and lifestyle changes, stroke has become the second most common cause of death and the primary cause of adult disability in China. Basic and clinical researchers have invested a significant amount of time to better understand stroke and identify novel therapeutic strategies.Acute ischemic stroke (AIS) accounts for more than 80% of all strokes.The pathogenesis and pathophysiologicalprocessesof AIS are very complicated. The elucidation of the complex role of cytokines including chemokines in AIS is important for understanding the pathophysiology of AIS.Macrophage migration inhibition factor (MIF) is a member of the chemokine-like function (CLF) chemokine family and is expressed in various cells, including T cells, monocytes, and endothelial cells. MIF has an important regulatory role in innate immunity and has been implicated in various inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease, and atherosclerosis. An increasing number of studies have focused on the relationship between MIF and AIS in recent years.Therole of MIF in stroke remains controversial. The clinical significant of MIF in AIS is still need to be elucidated.Chemokine like factor 1 (CKLF1) is a member of chemokine like superfamily. Several animal experiments showed that CKLF1 played an important role in AIS. In these study, CKLF1 was a damage factor in AIS. Whether the blood levels of CKLF1 were also elevated in patients with AIS? Does the change of CKLF1 level have a certain correlation with the clinical features of AIS patients? These questions should be answered.Fractalkine (FKN) is the only member of the CX3C chemokine. FKN played an important role in various diseases including atherosclerosis, vasculitis, rheumatoid arthritis andso on. The roles of FKN in AIS attract increasingly bigger attention in recent years. At present, there is no report on the correlation between FKN and AIS in Chinese patients. The relationship between FKN and clinical features of AIS patients is unclear.Several experimental studies have identified a close association between MIF, CKLF1, FKN and AIS. However, the clinical significance of them in AIS requires further elucidation. The discovery of novel biomarkers that may be used to identify individuals who are at risk for AIS, as well as provide a prognosis may significantly improve AIS prevention and treatment. In the present study, we measured the serum MIF, CKLF1, FKNlevels in Chinese patients with AIS, and investigated the correlation of serum MIF, CKLF1, FKN levels with AIS and the clinical significance in patients with AIS.Methods1. Collection of the clinical data:From December 2014 to September 2015, clinical data of 329 patients with AIS were collected from the Department of Neurology, Jinan Central Hospital Affiliated to Shandong University.102 patients who had arrived at the hospital24h later after the onset of symptoms were excluded.72 patients with recurrence and 9 patients with incomplete clinical data were also excluded. A total of 146 patients with AIS were finally enrolled in this study.Basic information including the risk of cardiovascular disease as well as other laboratory results of AIS patients and healthy controls were record.2. Enzyme linked immunosorbent assay(ELIZA)Serum levels of MIF, CKLF1 and FKN were tested by ELIZA according to the manufacturer's protocol. Serum levels were tested within 24 hours of symptom onset as well as 3 months later.3. Image analysis and clinical outcome assessmentsBrain MRI was performed within 24 h after admission using a 3.0-Tesla superconducting magnet. MRI with diffusion-weighted imaging (DWI) was available for all stroke patients. In these patients, the DWI lesion volumes were determined by an experienced neurologist who was blind to the clinical information and laboratory results of the patient. The infarct volume was calculated using the formula 0.5*a*b*c (where a is the max longitudinal diameter, b is the maximal transverse diameter perpendicular to a, and c is the number of 10mm-thick slices that contain the infarction.The clinical outcomes of the patients were evaluated using the modified Ranking Scale (mRS). A favorable outcome was defined as a mRS score of 0-2 and an unfavorable outcome was defined as a mRS score of 3-6 at 3 months.4. Statistical analysisContinuous variables were expressed as the means ± standard deviations (SDs). Differences between the groups were evaluated using the Mann-Whitney U and chi-square tests. The serum levels in the AIS patients and the normal controls were compared using the Mann-Whitney U test. Associations between the serum levels and the stroke NIHSS scores and infarct volumes were assessed using Spearman's rank correlation tests. Logistic regression analysis was used to determine the risk of stroke according to the serum levels. A receiver operating characteristic (ROC) curve was used to evaluate the accuracy of the serum MIF in the diagnosis of stroke. All statistical analyses were performed using IBM SPSS Statistics software Version 20 (IBM, Armonk, NY, USA). Graphs were created with GraphPad Prism 5 (GraphPad Software, San Diego, CA, USA).Results1.Baseline characteristicsOne hundred forty-six AIS patients were included in this study. There were no significant differences in age, gender, active smoking, TC, HDL, TG, or lymphocytes between the AIS and control groups. The prevalence rates of hypertension, diabetes, and hyperlipidemia were significantly increased in the AIS group compared with the control group. In addition, the serum LDL, FBG, HbAc, SBP, and DBP levels were significantly increased in the AIS group.2. MIF related results1)The averagelevel of serum MIF in the AIS patients was 1.230 ng/ml, compared with 0.876 ng/ml in the normal controls (P<0.0001);Serum MIF level in each subtype of AIS was higher than that in the normal controls;The chronic-stage serum MIF levels were significantly decreased compared with the acute-stage serum MIF levels (P<0.001) and were similar to the serum MIF levels in the control subjects (P=0.392).2)The serum MIF level was positively associated with the infarct volume (r=0.5515, P<0.0001). The serum MIF levels were increased with an increasing severity of stroke, as defined by the NIHSS score (r=0.5190, P<0.0001).3) The serum MIF levels in the patients with unfavorable outcomes were significantly increased compared with the patients with favorable outcomes (P<0.0001). In the logistic regression, increased serum MIF levels had a strong association with unfavorable outcomes, with an unadjusted OR of 2.264 (P<0.0001,95% CI, 1.782-2.827). Following adjustment for other significant outcome predictors (including age, gender, BMI, NIHSS score and infarct volume), the serum MIF levels were an independent long-term outcome predictor, with an adjusted OR of 1.113 (P=0.005,95% CI,1.051-1.238).4) To investigate the potential utility of the acute-stage serum MIF level in stroke prediction, a multivariate analysis was conducted. The serum MIF level was demonstrated to be an independent stroke predictor with an odds ratio (OR) of 1.985 (95% confidence interval[CI],1.672-2.252, P=0.011).An ROC curve was used to assess the accuracy of the serum MIF in the diagnosis of stroke. The optimal cutoff value of the serum MIF level was 0.821 ng/ml for an auxiliary diagnosis of AIS, which yielded a sensitivity of 74.7% and a specificity of 66.7%, with an area under the curve (AUC) of 0.717 (95% CI,0.638-0.796). The MIF exhibited a moderate discriminatory ability in the diagnosis of stroke.3.CKLF1 related results1) The average serum CKLF1 level in the AIS patients was37.730pg/ml, compared with 31.884pg/ml in the normal controls (P<0.0001); Serum CKLF1 level in each subtype of AIS was higher than in the normal controls; The chronic-stage serum CKLF1 levels were significantly decreased compared with the acute-stage serum CKLF1 levels (P<0.001) and were similar to the serum CKLF1 levels in the control subjects.2)The serum CKLF1 level was not associated with the infarct volume (r=0.1417? P=0.0879). There was no association between serum CKLF1 level and the NIHSS score (r=0.1230, P=0.1391).3)The serum CKLF1 levels in the patients with unfavorable outcomes were significantly increased compared with the patients with favorable outcomes (P<0.0001)4. FKN related results1) The average serum FKN level in the AIS patients was106.043pg/ml, compared with 80.621pg/ml in the normal controls (P<0.0001); Serum FKN level in each subtype of AIS was higher than in the normal controls; The chronic-stage serum FKN levels were significantly decreased compared with the acute-stage serum FKN levels (P<0.001).But it were higher than the serum FKN levels in the control subjects.2)The serum FKN level was not associated with the infarct volume (r=0.05947, P=0.4758). There was no association between serum FKN level and the NIHSS score (r=0.06708, P=0.4211).3)The serum FKN levels within 24 hours in the patients with unfavorable outcomes were similarto the patients with favorable outcomes (P=0.868). While, serum FKN levels at 3 months in patients with unfavorable outcomes were significantly lower than patients with favorable outcomes (P<0.001). Conclusions and significant1. We found for the first that serum MIF levels in 24 hours of symptom onset of patients with AIS were positively correlated with the infarct volume and the NIHSS score; Serum MIF levels could be a prognostic marker for patients with AIS.2. Serum CKLF1 levelswere elevated within 24 hours in patients with AIS.3. We demonstrated for the first time that serum FKN levels in 24 hours were elevated in Chinese patients with AIS. And the serum FKN level of AIS patients at3 months was still higher than normal.FKN revealed its potential therapeutic ability in AIS.