title: Effect of oral N-acetylcysteine on COPD patients with microsatellite polymorphism in the heme oxygenase-1 gene promoter.
abstract: BACKGROUND
  Heme oxygenase-1 (HO-1) plays a protective role as an antioxidant in the lung, and HO-1 gene promoter polymorphism has been shown to be associated with the severity and prognosis of COPD patients. N-acetylcysteine (NAC), an antioxidant/mucous modifier, has shown an uncertain benefit in COPD patients. We hypothesized that this polymorphism could be associated with the effectiveness of oral NAC.
  
  
  METHODS
  A total of 368 patients with COPD were recruited and the polymorphisms of their HO-1 gene promoter were classified into three subclasses according to the number of (GT)n repeats, as previously reported: class S (<27 (GT)n repeats), class M (27-32 (GT)n repeats), and class L (>32 (GT)n repeats). These subjects were then classified as L+ group (with the L allele: L/L, L/M, L/S) and L- group (without the L allele: M/M, M/S, S/S). All the patients were allocated to standard therapy plus NAC 600 mg bid over a 1-year period and were observed over that year.
  
  
  RESULTS
  The L- group saw improvements in forced expiratory volume in 1 second (FEV1) (from 1.44±0.37 to 1.58±0.38, P=0.04) and FEV1% predicted (from 56.6±19.2 to 59.7±17.2, P=0.03). No improvement was found in forced vital capacity of each group and the decline of forced vital capacity in both of the groups was not statistical significant. The number of yearly COPD exacerbations of the L- group was 1.5±0.66 which was lower than the 2.1±0.53 of the L+ group (P<0.01). For the changes of St George's Respiratory Questionnaire (SGRQ) score, only the activity score of the L- group was more significant than that of the L+ group (P=0.02). The improvement of the outcome of 6-minute walking distance test in L- group (from 290.1±44.9 meters to 309.7±46.9 m) was higher than that in the L+ group (from 289.7±46.2 m to 300.3±44.2 m) (P=0.03).
  
  
  CONCLUSIONS
  A 600 mg bid oral NAC treatment for 1-year on COPD patients without the L allele can improve the FEV1, FEV1% predicted, the SGRQ activity score, and the result of 6-minute walking distance test, and the exacerbation rate of the L allele carrier in COPD patients is much higher than in the COPD patients without the L allele.
authors.affiliation: The Second Department of Respiratory Medicine, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China.
authors.forename: Jia-Qiang
authors.initials: JQ
authors.lastname: Zhang
authors.affiliation: The Second Department of Respiratory Medicine, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China.
authors.forename: Jian-Qing
authors.initials: JQ
authors.lastname: Zhang
authors.affiliation: The Second Department of Respiratory Medicine, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China.
authors.forename: Li-Zhou
authors.initials: LZ
authors.lastname: Fang
authors.affiliation: The Second Department of Respiratory Medicine, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: The Second Department of Respiratory Medicine, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China.
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Fu
authors.affiliation: The Second Department of Respiratory Medicine, The First Affiliated Hospital of Kunming Medical University, Kunming, People's Republic of China.
authors.forename: Lu-Ming
authors.initials: LM
authors.lastname: Dai
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage* / Q000627:therapeutic use*; D000284:Administration, Oral; D000368:Aged; D000483:Alleles; D004247:DNA / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005260:Female; D005838:Genotype; D051547:Heme Oxygenase-1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*
chemical_list: D004247:DNA; D051547:Heme Oxygenase-1; D000111:Acetylcysteine
keywords: COPD prognosis; NAC treatment; chronic obstructive pulmonary disease; gene therapy