The Role Of Periostin In Asthma Phenotypes And Its Clinical Significance

Bronchial asthma(asthma)is a heterogeneous and chronic respiratory inflammatory disease,and it shows that different inflammatory cells infiltrate in airway tissue and secrete a variety of inflammatory mediators and cytokines,making airway smooth muscle contracted,airway epithelial mucus secretion increased,plasma leaked,mucosal edema and airway epithelial damaged,at last leading to airway hyperresponsiveness and airway inflammation.In recent years,for the heterogeneity of asthma,people gradually have carried out its phenotypic research,and in 2009 Global INitiative for Asthma(GINA)for the first time put forward the "phenotype" concept,and proposed the classification based on phenotype would help the treatment and prognostic judge of asthma.Classification of asthma phenotype makes the individualized treatment of asthma possible.According to the differences in main inflammatory cells,the inflammatory phenotype divides the asthma into four subtypes—eosinophilic asthma,mixed granulocytic asthma,neutrophilic asthma,and paucigranulocytic asthma.Based on the differences in airway inflammation mechanism,pathology,pathophysiology and clinical manifestations,asthma clinical phenotype divide asthma into children asthma,adults asthma,cough asthma with variants,typical asthma,eosinophils and non-eosinophilic asthma,severe asthma and so on.And the pathogenic characterics,pathophysiology and treatment of various asthma phenotypes are different.Therefore,it is of great clinical significance to explore the pathophysiological mechanism of asthma phenotype.Periostin is an extracellular matrix protein,also referred to as osteoblast-specific factor2,that plays an important role in tissue remodeling,which is typical symptoms of refractory asthma.Studies have shown that periostin is the downstream protein of asthma TGF-? and IL-4/IL-13 pathway,and TGF-? pathway is considered to be insensitive to cortisol.In addition,IL-4/IL-13 pathway is also the classic pathway for TH2 type asthma.Based on the role of periostin in airway remodeling and TH2 asthma,some scholars believe that it can be used as TH2 type of asthma or tissue remodeling biomarkers,However,the current study on periostin is limited to TH2 type asthma and non-TH2 type asthma,but lacks a systematic study of its relationship with expression of sputum and phenotype of asthma.Alveolar macrophages are predominant cells in eosinophil asthma and paucigranulocytic asthma.Some current studies have found that partial refractory asthmas may be associated with macrophages.Studies also have shown that macrophages may be closely linked with periostin,macrophages may secrete periostin,and periostin can in turn act on macrophages and other inflammatory cells to worsen the symptoms of asthma,however,whether macrophages can secrete periostin or not is inconclusive.Therefore,based on the above background,the research recruits asthma patients and human acute monocytic leukemia cell line(THP-1)as the subjects to explore the distribution characteristics of asthma phenotypes and molecular pathogenesis,in Changchun area;study the expression of periostin in the sputum and its role in severe asthma,inflammation phenotypes;explore the role of macrophages played in the relationship between periostin and asthma phenotype;provide a scientific basis for individualized diagnosis and the development of targeted therapy for asthma Methods1.According to the modified protocol on sputum induction,161 patients with asthma and 21 healthy volunteers were randomly selected to perform sputum induction,sputum smear and according to the internationally accepted standard of asthmatic inflammatory cell phenotype to determine the asthma inflammatory cell phenotype.Collect clinical data and asthma related questionnaires;Including asthma control questionnaire(ACQ),asthma control test questionnaire(ACT),asthma quality life questionnaire(AQLQ),hospital anxiety depression(HAD);And the subjects were asked to the related tests,such as blood routine test,pulmonary function test,fractional exhaled nitric oxide(Fe NO).2.The sputum supernatant and expression level of serum inflammatory mediators was detected by the ELISA method.Such as: Interleukin 1?(IL-1?),Interleukin 5(IL-5)?Interleukin 6(IL-6)?Interleukin 8(IL-8)?Interleukin 9(IL-9);There existed differences in clinical data,pulmonary function,Fe NO,clinical medication,expression level of inflammatory mediators between asthma group and healthy group,severe asthma group and non-severe asthma group,subtypes of asthma inflammation.3.The antigenic expression of periostin on the sputum smear was detected by using immunofluorescence technique.And the expression condition of periostin gene was detected by real time-PCR in the transformation of mononuclear cells from human acute monocytic leukemia cell line to macrophages.Results1.The characteristics of the object studied and the expression of periostin in asthmatic patients:(1)Subjects were 179 asthmatic patients and 24 healthy volunteers,and the induced sputum smears of 161 patients and 21 healthy volunteers were up to standard.(2)The asthma group and the healthy group were not significantly difference in the ages,male ratio,body mass index,smoking ratio.(3)FEV1 and the predicated value of FEV1% in the asthma group was significantly lower than these in the healthy group,but the NO(Fe NO)in the asthma group was obviously higher than that in the healthy group(P<0.05).(4)Compared with the healthy group,there was an increasing total numbers of inflammatory cells,eosinophils.(5)The periostin level of sputum in the asthma group[28(12,36)pg/ml] was higher than that in the healthy group[7(4,20)pg/ml],which was a significant difference(P < 0.05);In addition,the level of serum in the asthma group [12(7,18)pg/ml]was also extremely higher than that in the health group [5(4,8)pg/ml].The increased of sputum and serum periostin levels in asthma patients,have a certain value for the early diagnosis and differential diagnosis of asthma patients.2.Severe asthma group characteristics and periostin expression:(1)The severe asthma group and non-severe asthma group had no evident difference in ages,male ratio,body mass index,smoking ratio;(2)The FEV1,FEV1% in the severe asthma group was significantly lower than that in the non-severe asthma group,and Fe NO was higher so the differences were statistically significant(P <0.05);(3)The severe group had significantly lower scores than the non-severe group in asthma control test questionnaires and adult asthma quality of life scale,and obviously higher scores in hospital anxiety/depression and asthma control questionnaires;compared with non-severe asthma group;(4)The priostin level of sputum in the severe asthma group was higher[28(19,40)vs24(5,32)pg/ml,P<0.05],and even though the periostin level of serum was higher,it was not obvious(P>0.05).Indicating that the level of periostin in sputum can better indicate the severity of asthma.3.Asthma inflammatory cell phenotype characteristics and periostin expression:(1)According to the internationally accepted standard of asthmatic inflammatory cell phenotype,161 asthma patients were divided into four subtypes: 65 cases(36.3%)of eosinophilic asthma(EA),88 cases(49.2%)of paucigranulocytic asthma(PA),3 cases(1.7%)of neutrophilic asthma(NA),5 cases(2.8%)of mixed granulosa(MA);(2)Compared with the cases of mixed granulocytic asthma,paucigranulocytic asthma,eosinophilic asthma,cases of neutrophilic asthma were older in ages,higher males ratio,larger body mass index;(3)Compared with the cases of mixed granulocytic asthma,paucigranulocytic asthma,eosinophilic asthma,cases of neutrophilic asthma were lower in FEV1%,but no statistically significant;(4)Compared with the cases of NA,PA,EA,the cases of MA had higher scores in hospital anxiety and depression;the cases of PA had the highest scores in the asthma control test and adult asthma quality of life;(5)Periostin level of sputum supernatant in the cases of EA was the highest [30(20,38)pg/ml],followed by the cases of PA [20(8,34)pg/ml],MA [14(7,25)pg/ml],so the difference was statistically significant(P<0.05).periostin level of serum in the cases of EA was the highest 16(9,26)pg/ml,followed by the cases of PA [9(7,17)pg/ml],[MA 8(6,11)pg/ml],so the difference was statistically significant(P<0.05).This suggests that periostin may be involved in the pathophysiological mechanism of eosinophilic asthma.4.The relationship between periostin and inflammatory factors,Fe NO and inhalation medicine:(1)The increased periostin level of sputum supernatant,the level of sputum IL-5(r=0.714,P<0.05),sputum eosinophils number(r=0.100,P<0.05)were positively correlated;(2)The periostin level of serum and Fe NO(r=0.054,P < 0.05)were positively correlated;(3)The periostin level of serum in the patients inhaling ICS was the highest [13(6,19)pg/ml],followed by ICS/LABA group[9(7,17)pg/ml],and non ICS/LABA group[9(6,14)pg/ml],so the difference was statistically significant(P< 0.05);the periostin level of sputum had the same trend,but the difference was not statistically significant.Indicating that periostin is closely related to eosinophilic inflammation and serum periostin levels are susceptible to inhalation of ICS and LABA.5.Macrophage antigen and gene expression:(1)Immunofluorescence revealed periostin antigen expression in sputum smear macrophages.(2)Real time-PCR results showed that the expression level of intracellular periostin gene m RNA was ten times higher than the unpolarized macrophages when mononuclear cells of human were induced by phorbol ester to transform into macrophages,and then macrophages were induced to polarize to M2 by adding the IL4+IL13.Conclusions1.The subtypes of asthmatic inflammation of the subjects in Changchun area were mainly paucigranulocytic asthma,there were significant differences in clinical manifestations,pulmonary function,asthma-related questionnaires,inflammatory cell infiltration,and so on.Indicating that different subtypes have different pathophysiological processes,reflecting the heterogeneity of asthma patients.Therefore,this subtype classification lays the foundation for the study of asthma pathogenesis,and also provides a scientific basis for the treatment of heterogeneity.2.The levels of sputum and serum periostin were significantly higher in eosinophilic asthma and severe asthma in asthma patients in Changchun area,which was consistent with the results of foreign studies.Confirmed that periostin can be used as eosinophil asthma biomarkers and can be a better assessment of the severity of asthma.3.Macrophages can secrete periostin,and M2 macrophages are the main secretor,which helps to further explore the pathophysiology of PA-type asthma and EA-type asthma,and offer a new research direction for classification treatments of asthma.