Detection And Significance Of Scf And Mmp-9 In Induced Sputum Of Asthmatic Patients

Background and ObjectiveBronchial asthma(asthma) is a common respiratory disease which threatens human health worldwidely.In our country the asthma mortality,36.7 death/100,000 asthmatic patients,is higher than any other conutries in the world.The core of the asthmatic pathogenesis is airway inflammation.Stem cell factor(SCF),a mast cell grow factor,is involved in this process with its influence on the eosinophils and mast cells.Acording to different airway inflammation cells,the asthmatic airway inflammation can be divided into two categories:eosinophilic inflammation and non-eosinoohilic,the latter is characterized by the increase of neutrophils,of which Matrix metalloproteinase-9(MMP-9) is an effector molecule.Sputum induction is well developed,simple and safe and often serves as a tool to investigate the airway inflammation.This study want to find out the detectability and clinical significance of SCF in supernatant fluid of induced sputum in asthmatics;to research and compare with chronic brochitis patients the expression of neutrophil and its effector,MMP-9, in airway of asthmatic patients with different level of airway inflammation;to preliminarily discuss the impact of previous glucocorticosteroid administration on the airway inflammation status and correlated inflammation mediators;and to discuss the ehacteristics of airway inflammation and its machanism of asthma,especially severe asthma,from the angle of inflammation cell and its mediators and effectors of airway.Subjects and Methods All asthmatic patients came from the out-patient and in-patient department of the first affiliated hospital of Zhengzhou University from March,2008 to October,2008. Those asthmatic patients who are in remission,smokers and have respiratory infection or other disease were excluded.All asthmatics were divided into three groups by phase,severity and with or without previous glucosteroids adminiatration.Choose 15 heathy volunteers and 15 chronic bronchitis patients as control.Subjects with chronic bronchitis came from those who meet with the diagnosis criteria of chronic bronchitis and are members of Zhengzhou aluminum factory,during the prevalence study of lung cancer.Those who have acute upper or lower respiratory tract infection or any other disease were excluded.All asthmatics underwent lung fuction test and every subjects received sputum induction,which was succeeded by eosinophil and nutrophil counting and detection of SCF and MMP-9 in supernatant fluid by ELLISA.All data was expressed as(?)±S或(range).Use statistic software SPSS 11.0 as tool for data analysis and graph making.Use Student's t test to compare the diffrence between two groups and use ANOVA to compare multiple groups.Use double way analysis to compare the different means of group dividing.Use Pearson's test to test the correlation between numerical data.Setα=0.05 as size of test.Results①All subjects completed the procedure of inducing sputum smoothly.②The percentage of Eosinophil(Eos) in sputum of patients with asthma(5.16±4.08)%is higher than those in control(0.98±0.81)%and in patients with chronic bronchitis (1.03±0.65)%(F=14.392,P=0.000).It is also higher in moderate-severe asthmatics than in mild patients(t=4.685,P=0.000).There is no difference between patients with and without history of using glucosteroids(t=0.865,P=-0.391).③The percentage of Neutrophil(Neu) in induced sputum is lower in normal subjects than in patients with asthma and chronic bronchitis((26.32±10.27)%vs(41.72±16.74)%and (37.31±15.46)%,F=5.338,P=0.007).There is no difference in Neu counts between patients with acute exacerbation and chronic persistent asthma (t=0.262,P=0.795).Patients with moderate-severe asthma have higher percentage of neutrophil than those in mild group((47.29±14.97)%vs(32.25±15.57)%, t=5.347,P=0.000) and those with bronchitis(F=8.221,P＜0.01).The asthmatic patients with glucosteroids administrated have higher percentage of neutrophil than those without((46.18±15.95)%vs(34.71±15.86)%,t=2.581,P=0.013).④Contents of Stem Cell Factor(SCF) in supernatant fluid of induced sputum is higher in asthmatic patients than in normal subjects and patients with chronic bronchitis(F=9.77, P=0.000).And it is higher as well in asthmatic patients with acute exacerbation than those with chronic persistent asthma[(84.58±21.89) pg/ml vs(73.97±14.30) pg/ml, t=2.091,P=0.043)].The difference in SCF level of induced sputum is significant between moderate-severe asthmatic patients and mild patients.((87.46±18.81) pg/ml vs(64.84±6.91) pg/ml,t=6.325,P=0.000).Patients with history of glucosteroids have lower level of SCF than those without((72.88±13.33) pg/ml vs(88.82±22.44) pg/ml,t=2.941,P=0.006).⑤Concentrations of Matrix Metalloproteinase-9(MMP-9) in supernatant fluid of induced sputum is higher in patients with asthma and chronic brochitis than in normal subjects[(270.46±142.20)ng/ml,(205.21±101.35) ng/ml vs (157.67±108.96)ng/ml,F=4.660,P=0.012].The difference is not significant in MMP-9 level of induced sputum between patients with acute exacerbation and those with chronic persistent asthma.Moderate-severe asthmatic patients have higher level of MMP-9 in sputum than mild patients((323.76±148.15 ) ng/ml vs(179.85±67.52) ng/ml,t=4.869,P=0.000).Asthmatic patients who have used glucocorticosteroids have higher level of MMP-9 in induced sputum supernatant fluid than those who have not((315.93±151.85)ng/ml vs((199.00±88.99) ng/ml),t=3.565,P=0.001).⑥Within the simple methods of dividing groups,severity has the most significance, which is succeeded by the history of glucosteroid administration.By comparing the interaction effects of those methods,severity and the history of glucosteroid administration have the most effects when crossed:the taking of glucosteroid can reduce the SCF level and elevate the MMP-9 concentration in supernatant fluid of induced sputum in moderate-severe asthmatic patients,but not in mild patients (respectively,P＜0.01,P＜0.05).⑦Lung function has a negative correlation with counts of Eos in sputum of asthmatic patients(r=-0.389,P=0.004) and level of SCF (r=-0.487,P=0.000),and the latter has a a possitive correlation with the former (r=0.296,P=0.03).Similarly,lung function has a negative correlation with proportion of Neu(r=-0.62,P＜0.001) and the concentration of MMP-9(r=0.604,P＜0.001) in asthmatic patients,and MMP-9 level is positively correlated with counts of neutrophil(r=0.604,P=0.000).Conclusions①The technique of inducing sputum with properties of high safty and good repeatability is appropriate to be a common method to evaluate the status of airway inflammation.②SCF,which is invloved in the pathogenesis of asthma and can be used for tools on evaluating the airway inflammation,is detecable in supernatant fluid of induced sputum.It as well possesses clinical value on diagnosis,differencial diagnosis and evaluating the severity of asthma.③Previous glucosteroids administration impacts on the level of neutrophil and MMP-9in asthmatic airway, which are both invloved in the formation of asthmatic airway inflammation.