| Background and objective:Bronchial asthma is a common and frequently encountered disease of respiratory system,the incidence of which is increasing in recent years.Bronchial asthma is a chronic allergic inflammation of the airway,which involves a variety of cells and cell components,but the pathogenesis is not yet entirely clear.In recent years,the immune inflammation mechanism is considered to be an important mechanism of the disease,and eosinophils as the main effector cells participate in the inflammation process.Microparticles are membrane-contained vesicles with a diameter of 100 nm to 2 ?m,released by cells when they were activated,damaged or apoptotic.Microparticles have a variety of biological activities,and play roles in cell signal transduction,proinflammatory action,immune regulation,and tissue repair[1].Through interacting with target cells,microparticles can start target cells' biological effects,which is closely related to the occurrence and development of diseases.It has been confirmed that microparticles have a close relationship with autoimmune diseases,such as SLE [2].In patients of eclampsia,diabetes,sepsis,cancer,and cardiovascular disease [3],the levels of circulating microparticles are higher than those in normal people,which is closely related to the severity and prognosis of the diseases.Through detection and analysis of microparticles,it can optimize the diagnosis and treatment of the diseases.In the previous study,our group found that lymphocyte-derived microparticles(LMPs)in BALF was increased in patients with COPD,and the study in vitro has confirmed that microparticles derived from T lymphocytes could restrain the growth of epithelial cell in the airway,through AKT/ FOXO1 pathway,which blocked the airway epithelial cells in G1 phase of cell cycle.Moreover,microparticles derived from T lymphocytes promoted epithelial cells' apoptosis depending on the activation of p38-MAPK pathway.According to new researches,respiratory infections can trigger the release of microparticles,through activation of ATP,and thay can release IL-1beta and IL-18 by P2X7 / caspase 1 channel,which participates the activation of neutrophils and macrophages in the airway,and the maintaining of chronic inflammation [4-5].However,infections often lead to acute asthma attacks,aggravate airway inflammation and respiratory symptoms,and then bring down lung function[6-7].Thus,microparticles are involved in the process of chronic inflammation in the airway,and plays a role in promoting inflammation.During the process of chronic airway inflammation in asthma,there are a large number of microparticles in the activation or apoptosis of eosinophils as the main effect cells.But the change and the effect of eosinophil-derived microparticles have not been reported at home and abroad.So this study intends to explore preliminarily the change of circulating eosinophil-derived microparticles in asthma before and after treatment,and the possible relationship among the change?disease severity and treatment efficacy,in order to further reveal the pathogenesis of asthma,and provide a new idea for the diagnosis and treatment of asthma.Methods:Sixty-five subjects who met the inclusion criteria were enrolled in this study,and they were divided into 32 cases of the asthma group and 33 cases of the normal control group.Their peripheral venous blood samples were collected,centrifuged and then marked with corresponding antibodies.The numbers of eosinophil-derived microparticles in every 100?l supernate was determined by flow cytometry.In adition,asthma group still needs to do the ACT scale,pulmonary function(FEV1,FEV1 %),Fe NO measurement,blood routine(Eos count),and allergen skin prick test examination.After three months of regular anti-asthmatic treatment(with inhaled corticosteroids + long-acting beta 2 agonists),the equivalent volume of venous blood was extractedin every subject and then the levels of eosinophil-derived microparticles were detected,the above indexes were reviewed.The change rate(?)of these indexes before and after therapy is calculated,which equal to(value before therapy-value after therapy)/value before therapy × 100%.Also,the change rate of eosinophil-derived microparticleswas analysed and compared with the change rate of other asthmatic indexes' change.The data was correlatively studied.According to the allergic condition and the level of asthma control,asthma group can be divided into four subgroups,which are allergic group,non-allergic group and well-controled group,uncontroled group,and the levels of microparticles were analysed.Results:1.Conparison between asthma group and control group1.1 The levels of eosinophil-derived microparticles in asthma group before?after treatment and control group respectively:(136.81±150.08)/100?l?(50.65±33.09)/100?l?(36.78±19.99)/100?l.1.2 The level of eosinophil-derived microparticles in asthma group before treatment was higher than that in control group,the difference was statistically significant(Z =-4.069,P< 0.01).1.3 The level of eosinophil-derived microparticles in asthma group after treatment was higher than that in control group,there was a statistical difference(t = 2.052,P = 0.044).1.4 After treatment the level of eosinophil-derived microparticles significantly dereased in circulating blood of patients with asthma(Z=-4.526,P<0.01).2.Asthma subgroup analysis2.1 The levels of eosinophil-derived microparticles in well-controled group and uncontroled group before treatment respectively:(119.05±112.41)/100?l ?(156.93±186.06)/100?l,and after treatment respectively:(39.76±20.83)/100?l ?(63.00±40.29)/100?l.There was no difference in the levels of eosinophil-derived microparticles(Z=-0.227,P=0.821),between the well-controled group and uncontroled group before treatment.But statistical difference was seen between well-controled asthma group and uncontroled group after treatment(t=-2.086,P=0.046).2.2 The levels of eosinophil-derived microparticles in allergic group and non-allgergic group before treatment respectively:(149.64±154.10)/100?l?(126.83±150.58)/100?l,after treatment respectively:(50.50±31.30)/100?l ?(49.77±35.16)/100?l.And the levels of eosinophil-derived microparticles had no obvious differences between allergic group and non-allgergic group before and after treatment(t = 0.421,P = 0.677;t = 0.006,P = 0.952).2.3 The rate of well-controled asthma in allergic group { [9](64.3%)} was slightly higher than that of non-allergic group{ [8](44.4%)},but the difference was not statistical(chi-square = 1.245,P = 0.265).3.The correlation between eosinophil-derived microparticles and other clinic indicators3.1 The lung function index FEV1,FEV1% of patients with asthma improved after treatment(P < 0.01),and ? eosinophil-derived microparticles had significantly negative correlations with ? FEV1,? FEV1%(r =-0.558,P < 0.01;r =-0.453,P = 0.005).3.2 The blood eosinophil count decreased after treatment in patients with asthma(P < 0.01),? eosinophil-derived microparticles showed positive correlation with ? eosinophil count(r = 0.625,P < 0.01).3.3 The levels of Fe NO were lower than before treatment in patients with asthma(P < 0.01),? eosinophil-derived microparticles represented a positively correlated relationgship with ? Fe NO(r = 0.313,P = 0.041).3.4 After treatment ACT scores increased in patients with asthma(P < 0.01),and there was a negative correlation between ? eosinophil-derived microparticles and ? ACT(r =-0.399,P = 0.012).Conclusions:1.In patients with asthma,the level of circulating eosinophil-derived microparticles is obviously higher than that in healthy controls,and the change of which is consistent with that of inflammatory markers,such as the blood eosinophil and Fe NO.The result suggests that eosinophil-derived microparticles are involved in the pathophysiological process of chronic airway inflammation in asthma.2.Eosinophil-derived microparticles have negative correlations with FEV1,FEV1 % and ACT scores,which states that eosinophil-derived microparticlesmay associated with the severity of asthma.3.The number of circulating eosinophil-derived microparticles is increased in asthma patients,and decreased after treatment.Therefore,dynamical monitoring its level may contribute to the assessment of asthma control. |
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