Mucus hypersecretion is a distinguishing feature of chronic inflammation diseases, such as asthma,chronic bronchitis, bronchiectasis and cystic fibrosis Mucus hypersecretion leads to impairment of mucociliary clearance, abnormal bacterial plantation, mucus plug in the airway, and dysfunction of gas exchange.5 To block this vicious cycle, chronic inflammation in the airway must be controlled and mucus hypersecretion must be reduced.
Background Chronic obstructive pulmonary disease （COPD） is usually complicated with mucus overproduction in airway. Recently the increased expression of the human calcium-activated chloride channel 1 （CaCC1） was found to play an important role in mucus overproduction in the asthmatic airways. To investigate the relationship of CaCC1 and mucus overproduction in the airway of Chinese patients with COPD, the expressions of CaCC1, MUC5AC and mucus in bronchial tissues were examined. Methods Bronchial tissues were obtained from fiberoptic bronchoscopy and bronchial biopsy in West China Hospital from April to July in 2004. Twenty-five patients were diagnosed as the patients with COPD overproduction, and other 20 were the control subjects. The expressions of CaCC1, MUC5AC and mucin in bronchial tissues were detected by reverse transcriptase-polymerase chain reaction （RT-PCR）, in situ hybridization with digoxigenin （DIG）-Iabeled RNA probe, immunohistochemical and alcian blue-periodic acid Schiff （AB-PAS） staining, respectively. Results Compared with the control group, the stronger expressions of CaCC1 were further detected throughout the bronchial tissues from patients with COPD （P〈0.01）. Furthermore, the stronger expressions of the CaCC1 mRNA were related to the severity of airflow obstruction. Samples from COPD showed a stronger staining for MUC5AC than those in control subjects （P〈0.01） and AB-PAS staining revealed more mucins in COPD patients＇ submucosal gland comparing with that in control subjects （P〈0.01）. Expression levels of the CaCC1 mRNA were respectively negatively correlated with the patients＇ forced expiratory volume in one second （FEV~） / forced vital capacity （FVC） data, FEV1% predicted data, V50% predicted data, V25% predicted data （r=-0.43, r=-0.43, r=-0.35, r=-0.36, P〈0.01, P〈0.01, P〈0.05, P〈0.05）. While the expression levels of the CaCC1 mRNA were well correlated with the expression levels of the MUC5AC mRNA of airway epithelium and the PAS
WANG Ke FENG Yu-ling WEN Fu-qiang CHEN Xue-rong OU Xue-mei XU Dan YANG Jie DENG Zhi-pin
Background Mucus hypersecretion in the respiratory tract and goblet cell metaplasia in the airway epithelium contribute to the morbidity and mortality associated with airway inflammatory diseases. This study aimed to examine the effect and mechanisms of simvastatin on airway mucus hypersecretion in rats treated with lipopolysaccharide （LPS）. Methods Mucus hypersecretion in rat airways was induced by intra-tracheal instillation of LPS. Rats treated with or without LPS were administered intra-peritoneally simvastatin （5 and 20 mg/kg） for 4 days. Expression of Muc5ac, RhoA and mitogen-activated protein kinases （MAPK） p38 in lung were detected by real-time polymerase chain reaction （PCR）, immunohistochemistry or Western blotting. Tumor necrosis factor （TNF）-α and IL-8 in bronchoalveolar lavage fluid （BALF） were assayed by an enzyme-linked lectin assay and enzyme linked immunosorbent assay （ELISA）. Results Simvastatin attenuated LPS-induced goblet cell hyperplasia in bronchial epithelium and Muc5ac hypersecretion at both the gene and protein levels in lung （P 〈0.05）. Moreover, simvastatin inhibited neutrophil accumulation and the increased concentration of TNF-α and IL-8 in BALF follows LPS stimulation （P 〈0.05）. The higher dose of simvastatin was associated with a more significant reduction in Muc5ac mRNA expression, neutrophil accumulation and inflammatory cytokine release. Simultaneously, the increased expression of RhoA and p38 MAPK were observed in LPS-treated lung （P 〈0.05）. Simvastatin inhibited the expression of RhoA and p38 phosphorylation in lung following LPS stimulation （P 〈0.05）. However, the increased expression of p38 protein in LPS-treated lung was not affected by simvastatin administration. Conclusions Simvastatin attenuates airway mucus hypersecretion and pulmonary inflammatory damage induced by LPS. The inhibitory effect of simvastatin on airway mucus hypersecretion may be through, at least in part, the suppression of neutrophil accumulation and
OU Xue-mei WANG Bai-ding WEN Fu-qiang FENG Yu-lin HUANG Xiang-yang XIAO Jun
Background The main risk factor for chronic obstructive pulmonary disease （COPD） is cigarette smoking. However, only 10%-20% of chronic heavy smokers develop systematic COPD. We hypothesized that the inheritance of gene polymorphisms could influence the development of COPD, which was investigated by studying two single nucleotide polymorphisms （SNP） in exon 1 of the transforming growth factor-β1 （TGF-β1） gene. Methods We enrolled 219 patients with COPD as the research group and 148 healthy people as the control group, all of whom were Chinese Han people. The polymorphisms of the TGF-β1 gene, 869T/C and 915G/C, were analyzed using the method of amplification refractory mutation system-polymerase chain reaction （ARMS-PCR）. Results The occurrence of the TGF-β1 gene 869T/C polymorphism in patients with COPD was significantly different from the control group （P 〈0.05）, in which the relative risk of this disease increased in cases who had the C allele （OR： 1.131, 95% CI： 1.101-1.539）. There was no increased frequency of TGF-β1 915G/C gene in COPD patients compared with control subjects （P 〉0.05）. Conclusions The polymorphism 869T/C in TGF-β1 gene has a significant association with disease occurrence in COPD patients and the C allele might be a risk factor. The homozygous wild-type CC of 869T/C on TGFβ1 could be a predisposing factor in COPD and those who carry the C allele might have particularly susceptibility to developing COPD.
LIU Dai-shunLI Xiao-ouYING Bin-wuCHEN LeiWANG TaoXU DanWEN Fu-qiang
