Detection And Clinical Significance Of Serum Airway Remodeling-associated Factors In Wheezy Infants And Toddlers

Background:Number of patients with bronchial asthma(asthma) is continuously growing these years.Asthma has become one of the main diseases endangering people's health.The prevention and treatment of asthma have been paid attention widely.Data from Chinese epidemiologic survey of asthma in children aged 14 and under showed 85%of childhood asthma started before the age of 3.So,the prevention and treatment of asthma in infants should be especially emphasized.Wheezing is a common respiratory symptom in infants.About 1/3 of children wheezed at least once before the age of 3. And most of them have good prognosis,while part of them could develop into asthma.Airway inflammation and airway remodeling are the two main pathological characteristics,while the latter is an important factor effecting asthmatic curative effect. Some studies showed airway remodeling and airway inflammation were concomitant and influenced by each other.Airway remodeling could be formed in early stage of asthma in children,even before diagnosis.But whether airway remodeling occurred in infants with wheezing before diagnosis of asthma and what are the risk factors haven't yet been reported.Early treatment with glucocorticoid could help to prevent airway remodeling,but could not reverse airway remodeling already formed.Early reveal and intervene of airway remodeling are the keys to prevention and treatment of asthma in children.Objectives:1.To detect serum level of matrix metalloproteinase(MMP)-9,tissue inhibitors of metalloproteinase(TIMP)-1,transforming growth factor beta 1(TGF-β1) and MMP-9/TIMP-1 in wheezing infants,and compare with that of healthy infants.2.To detect change of serum MMP-9,TIMP-1,TGF-β1 and MMP-9/TIMP-1 in wheezing infants with different wheezing attacks,etiological pathogens and hereditary background.Methods:One hundred and twenty-seven wheezing infants and 30 healthy infants were enrolled in this study.Serum level of MMP-9,TIMP-1 and TGF-β1,serum secretion IgE and total IgE,serum IgG and IgM of Mycoplasma pneumoniae(MP),Chlamydia pneumoniae(CP) and Chlamydozoa trachomatis(CT) by enzyme-linked immunosorbent assay(ELISA),were measured.Respiratory virus antigen by direct immunofluorescence and DNA of MP,CP and CT by polymerase chain reaction(PCR) were also detected.Then serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 among different groups were compared.Results:1.Serum level of MMP-9 in wheezing infants is higher than control(p＜0.05),and MMP-9/TIMP-1 lower than control(p＜0.05),both with statistical significance.Serum level of TIMP-1 and TGF-β1 have no significant differences when compared to control (p＞0.05).2.Serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 have no significant differences between first time wheezing group and recurrent wheezing group (p＞0.05).3.Serum level of MMP-9/TIMP-1 and TGF-β1 are lower in respiratory syncytial virus(RSV) positive group than in RSV negative group with statistical significance (p＜0.05 and p＜0.1 respectively).4.Serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 have no significant differences between non-atypical-pathogenic-infection group and atypical-pathogenic-infection group(p＞0.05).5.Serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 have no significant differences between non-asthma-high-risk group and asthma-high-risk group (p＞0.05).6.Serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 have no significant differences between high IgE group and normal IgE group(p＞0.05).7.Serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 have no significant differences between non-high-risk group and high-risk group in RSV positive patients(p＞0.05).8.Serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 have no significant differences between high IgE group and normal IgE group in RSV positive patients(p＞0.05).Conclusions:1.Serum level of MMP-9 is high and MMP-9/TIMP-1 is low in wheezing infants, indicating high risk factors of airway remodeling in wheezy infants. 2.Serum level of MMP-9/TIMP-1 and TGF-β1 are lower in RSV infection patients, indicating RSV infection may be a trigger factor of airway remodeling.3.No significant influence of recurrent wheezing,atypical pathogenic infection, high IgE or asthma high risk on serum level of MMP-9,TIMP-1,MMP-9/TIMP-1 and TGF-β1 are observed.