| Research background:Chronic obstructive pulmonary disease(COPD)is a chronic inflammatory airway disease characterized by persistent airflow restriction.It is expected to be the world's third leading cause of death by 2030.Pseudomonas aeruginosa(PA)which can cause continuous deterioration of lung function and significantly increase the rate of readmission,is one of the bacteria with the highest detection rate in sputum culture of COPD,.PA is considered to be associated with the acute exacerbation of COPD and poor prognosis.Myeloperoxidase(MPO)which is a marker of neutrophil activation is a heme peroxidase found mainly in neutrophils.MPO is involved in pathological changes such as pulmonary hypertension,emphysema and small airway remodeling in COPD patients.PA persists in COPD patients.and induces the formation of neutrophils extracellular traps.Neutrophils extracellular traps can activate neutrophils to release MPO.Then aggravate the severity of COPD patients and affecting their prognosis.At present,the clinical value of MPO in COPD patients infected by PA has not been reported in China.Purposes:The purpose of this study was to investigate the changes in serum MPO levels and the predictive value of MPO detection in patients with COPD with PA infection.Methods:In this study,we enrolled 126 patients diagnosed COPD in the outpatient and inpatient department of the third hospital of nanchang city from October 1,2018 to September 30,2019 in the study,of whom 47 cases were identified as PA by sputum culture and included in the PA(+)group.And 79 COPD patients without PA in sputum culture were included into PA(-)group.Another 40 healthy patients were selected as the control group.Serum MPO levels were measureded by enzyme-linked immunosorbent assay(ELISA);Interleukin-6(IL-6)levels were measured by up-forwarding light;The concentrations of c-reactive protein(CRP)were determined by rate scattering turbidimetry;Blood analysis indexes were determined by electrical resistance.Lung function index forced expiratory volume in the first second/forced vital capacity(FEV1/FVC)and percentage of predicted value of forced expiratory volume in the first second(FEV1%pred)were measured by lung function tester.Spearman correlation analysis of the correlation between MPO,Il-6,CRP and other laboratory indicators and lung function.Binary Logistic regression analysis of the risk factors influencing the colonization of pseudomonas aeruginosa in COPD patients.Results:(1)The levels of NLR,IL-6 and CRP in PA(+)group were significantly higher than those in PA(-)group and healthy control group(P<0.05).The lung function indexes FEV1%pred and FEV1/FVC in PA(+)group and PA(-)group were statistically different(P<0.05).(2)The serum MPO level of the PA(+)group(253.39±88.93ng/ml)was significantly higher than that of the PA(-)group(152.87±60.97ng/ml)and the control group(61.25±22.10ng/ml).The difference was statistically significant(P<0.01).(3)MPO levels were associated with inflammatory markers CRP,IL-6,neutrophil lymphocyte ratio(NLR)and whole blood neutrophils(NEUT)(r=0.553,P=0.000;r=-0.549,P=0.000;r=0.554,P=0.000;r=0.593,P=0.000).The correlation between MPO and IL-6 was the strongest(r=0.593)(4)MPO levels were negatively correlated with lung function index FEV1/FVC(r=-0.579,P=0.000)and FEV1%pred(r=-0.528,P=0.000).(5)Logistic regression analysis confirmed that MPO and CRP were independent risk factors for pseudomonas aeruginosa colonization in COPD patients,with OR(95%CI)1.420(1.242~1.628)and 1.317(1.134~1.229),respectively.(6)Patients were graded according to the GOLD grading standard according to the results of pulmonary function test,and the levels of MPO were significantly different in patients with different GOLD grades(P<0.05).Conclusions:Serum MPO levels are elevated in COPD patients with PA infection.MPO can be used to reflect the state of inflammatory response in patients and is a potential biomarker for disease monitoring. |
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