Expression And Significance Of Macrophage Migration Inhibitory Factor In Peripheral Blood Of Patients With Chronic Obstructive Pulmonary Disease

BackgroundCOPD is a leading cause of disability and death worldwide, with variable reports of5-13%prevalence rates, and8%to10%or higher among those of approximate age40years. Prevalence rates are directly related to tobacco smoking and indoor air pollution, and are expected to rise as smoking rates continue to increase, notably among women and in developing countries. The prevalence of COPD in smokers is approximately20%as compared with4%in nonsmokers.As a consequence, by2030COPD is expected to represent the third leading cause of death. COPD accounts for a significant proportion of healthcare budgets.Recent studies have shown that COPD is associated not only with an abnormal inflammatory response of the lung but also with systemic inflammation, including systemic oxidative stress, activation of circulating inflammatory cells,and increased circulating levels of inflammatory cytokines. The local inflammatory process in the lungs can affect peripheral tissues either by the direct effect of released cytokines and chemokines or indirectly by activation of peripheral inflammatory cells. COPD can not only affect the proximal and peripheral airways, lung parenchyma and vasculature, but also result in comorbidities,such as cardiovascular disease, diabetes mellitus, depression, weight loss and muscle dysfunction.Results from a large number of studies,a large number of chemokines, cytokines and proteinases, including NF-κB、IL-6, are believed to play a role in the pathogenesis of chronic obstructive pulmonary disease,and lead to a small airway fibrosis and alveolar destruction.Above, the inflammatory response play an important role in the pathogenesis of chronic obstructive pulmonary disease.The target treatment of inflammatory mediators may be effective.But because too many inflammatory mediators involved in inflammation of COPD, the target treatment of a single inflammatory mediators do not have many clinical benefits. So finding out characteristic of inflammatory mediators and the source of inflammatory mediators causing inflammation is important for COPD.Nuclear factor-kappa B is a protein which can specifically bind to promoter-κB sequence and activate gene transcription. It plays an important role in immune response, inflammation, cell differentiation and growth, cell adhesion, and apoptosis.NF-KB and IκB non-covalently combine into inactive dimers in the cytoplasm. When exposure to activation signals, NF-κB dissociates with IκB, transfers into the nucleus, binds to DNA promoter of response element, and regulates the transcription of inflammatory gene, inducing upregulation of adhesion molecules and downstream cytokines, including IL-6. Therefore NF-κB is involved in the start of the inflammatory response and many studies have proved that NF-kB plays an important role in the pathogenesis of COPD.As a downstream cytokine of NF-kB,IL-6was proved to play an important role in the inflammatory response of COPD.Macrophage migration inhibitory factor(MIF) as a preinflammation factor, considered to be a c ritical regulator in the pathogeneis of various inflammatory conditions, can induced a large of inflammation media through NF-kB pathway,as same as inflammation media in chronic obstructive pulmonary disease. So we hypothesize that MIF may have a role in the pathogeneis of chronic obstructive pulmonary disease.The expression of macrophage migration inhibitory factor, NF-κB,and IL-6were investigated in the peripheral blood of patients with chronic obstructive pulmonary disease and to explor their role in the pathogenesis of chronic obstructive pulmonary disease.ObjectiveThe expression and significance of macrophage migration inhibitory factor were investigated in the peripheral blood of patients with chronic obstructive pulmonary disease. The relation in MIF, NF-kB, IL-6and their role in the pathogenesis of COPD were analysed. The relation between them and FEV1%were analysed too in COPD group.MethodsThe subjects were divided into three groups:AECOPD group, SCOPD group, control group. All patients received Spirometry. Exclusion criteria:autoimmune diseases (i.e.,rheumatoid arthritis,systemic lupus erythematosus, vasculitis) malignancy, urologic diseaseacute (i.e.,acute and chronic glomerulonephritis, nephrotic syndrome), disease of digestive tract (i.e., hepatitis, cirrhosis, and inflammatory bowel disease), coronary heart disease (i.e., angina and myocardial infarction), respiratory disease (i.e., bronchial asthma, allergic rhinitis, active pulmonary tuberculosis).Inclusion criteria:COPD diagnostic criteria developed by the2010GOLD,FEV1/FVC<70%. The matched control group without COPD, had no differences in gender, age, smoking with COPD groups.From February through July2012,the serum concentrations of macrophage migration inhibitory factor and IL-6, the expression of MIF in T cells, the level of PBMC MIF-mRNA and NF-κB were compared, using ELISA,flow cytometry, RT-PCR, Western blot, respectively, among patients with acute COPD (AECOPD, n=25),patients with stable COPD (SCOPD, n=25) and controls without COPD (n=25). All the data were analysis according to the characteristics of data using SPSS13.0software.Results1.AECOPD group including20males and5females, mean age62.2±4.9years old, with an average of7.78years courses,average FEV1%pred51.9±8.2, average FEV1/FVC56.8±5.7; SCOPD group including19males and6females, mean age59.2±5.1years old, with an average of6.56years courses, average FEV1%pred53.4±7.3, average FEV1/FVC60.9±4.4; Control group including20males and5females, mean age59.4±4.6years old, average FEV1%pred87.8±5.6, average FEV1/FVC82.5±11.3; All the patients have a history of smoking.2.The ratio of CD4+MIF+T cells was significantly higher in the AECOPD group (76.81±14.65%), compared with the stable COPD group (60.09±16.03%) and the control group(65.88±16.64%)(P=0.002and0.037, respectively). Nevertheless, there was no significant difference between the stable COPD group and the control group (P=0.302).Similarly, the ratio of CD8+MIF+T cells was significantly higher in the AECOPD group (76.94±19.96%), compared with the stable COPD group(58.48±25.28%) and the control group(55.92±29.90%)(P=0.010and0.012, respectively). And the difference between the stable COPD group and the control group was not statistically significant (P=0.975). The ratio of CD4+MIF+T cells or CD8+MIF+T cells is negatively correlated to the value of FEV1/expected value%in stable COPD group.3.With regards to the serum concentration of MIF, there was no significant difference among AECOPD group, stable COPD group and control group (128.94±30.31pg/ml,119.57±17.64pg/ml,123.22±33.55pg/ml, respectively; F=0.786, P=0.460).4.The correlation between the serum concentration of MIF and the ratio of CD4+MIF+T cell or CD8+MIF+T cell was insignificant(P=0.803and0.224, respectively)5.1n agreement with the findings of the expressions of MIF in CD4+or CD8+T cells, the level of PBMC MIF-mRNA was significantly higher in the AECOPD group (0.0303±0.03075),compared with the stable COPD group(0.0140±0.01819)and the control group (0.0186±0.00711)(P=0.004and0.036, respectively). And the difference between the stable COPD group and the control group was not statistically significant (P=0.422).6.There was a significant correlation between the level of MIF-mRNA and either the ratio of CD4+or CD8+MIF+T cells (r=0.323, P=0.010; r=0.354, P=0.004, respectively),but not the serum concentration of MIF (P=0.459).7.The expression of NF-κB of PBMC in AECOPD group, stable group, control group were0.9659±0.0754,0.9496±0.14393,0.9182±0.05131respectively, and there were no significant difference. As the same, there were no significant difference in the three groups (grade Ⅱ、Ⅲ、Ⅳ) of patients with COPD.8.The concentration (pg/ml) of IL-6in AECOPD group, stable group, control group were31.88±19.46,44.46±16.18,23.86±9.93respectively. Compare the serum IL-6:stable COPD group is higher than AECOPD group, and AECOPD group is higher than control group, the difference are significant(x2=10.328, P=0.006). As the same,the difference are significant in the three groups (grade Ⅱ、Ⅲ、Ⅳ) of patients with COPD.The level of serum IL-6is negatively correlated to the value of FEV1/expected value%either stable COPD group or AECOPD group (r=-0.497, P=0.011; r=-0.613, P=0.001).9.The concentration of CRP(mg/l) in AECOPD group, stable COPD group, control group were28.13±38.56,8.21±16.31,2.86±28.13respectively. Compare the serum CRP:AECOPD group is higher than stable COPD group, and stable COPD group is higher than control group, the difference are significant (χ2=33.051, P<0.01);10.There was a significant correlation between the level of NF-κB and the ratio of CD4+or CD8+MIF+T cells in SCOPD group (r=0.497, P=0.010; r=0.854, P=0.004, respectively).The correlation between the MIF and IL-6was insignificant in COPD patients.Conclusions1. The overexpression of MIF in CD4+、CD8+T cell may be involved in the acute exacerbation of COPD, but not paly a role in the chronic inflammation of COPD.2.The expression of NF-κB of PBMC were no significant difference and Suggests that they were not concerned with systemic inflammation of COPD.3. The concentration of IL-6were significantly higher in stable group and may play a critical role in the pathogenesis of COPD. The level of serum IL-6is negatively correlated to the value of FEV1%in either stable COPD group or AECOPD group,and can reflect the severity of airway obstruction.