title: Leukocyte Mitochondrial DNA Copy Number Is Associated with Chronic Obstructive Pulmonary Disease.
abstract: BACKGROUND
  Oxidative stress is known to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Evidence suggests that leukocytes mitochondria DNA (mtDNA) is susceptible to undergo mutations, insertions, or depletion in response to reactive oxidative stress (ROS). We hypothesize that mtDNA copy number is associated with the development of COPD.
  
  
  RESULTS
  Relative mtDNA copy number was measured by a quantitative real-time PCR assay using DNA extracted from peripheral leukocytes. MtDNA copy number of peripheral leukocytes in the COPD group (n = 86) is significantly decreased compared with non-smoker group (n = 77) (250.3± 21.5 VS. 464.2± 49.9, P<0.001). MtDNA copy number in the COPD group was less than that in the healthy smoking group, but P value nearly achieved significance (250.3± 21.5 VS. 404.0± 76.7, P = 0.08) MtDNA copy number has no significance with age, gender, body mass index, current smoking, and pack-years in COPD group, healthy smoker group and no smoker group, respectively. Serum glutathione level in the COPD group is significantly decreased compared with healthy smoker and non-smoker groups (4.5± 1.3 VS. 6.2± 1.9 and 4.5± 1.3 VS. 7.1±1.1 mU/mL; P<0.001 respectively). Pearson correlation test shows a significant liner correlation between mtDNA copy number and serum glutathione level (R = 0.2, P = 0.009).
  
  
  CONCLUSIONS
  COPD is associated with decreased leukocyte mtDNA copy number and serum glutathione. COPD is a regulatory disorder of leukocytes mitochondria. However, further studies are needed to determine the real mechanisms about the gene and the function of mitochondria.
authors.affiliation: Division of Pulmonary & Critical Care Medicine, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Department of Respiratory Therapy, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Shih-Feng
authors.initials: SF
authors.lastname: Liu
authors.affiliation: Department of Respiratory Therapy, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan; Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
authors.forename: Ho-Chang
authors.initials: HC
authors.lastname: Kuo
authors.affiliation: Department of Respiratory Therapy, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
authors.forename: Ching-Wan
authors.initials: CW
authors.lastname: Tseng
authors.affiliation: Department of Anatomy, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Hung-Tu
authors.initials: HT
authors.lastname: Huang
authors.affiliation: Division of Pulmonary & Critical Care Medicine, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Yung-Che
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Division of Pulmonary & Critical Care Medicine, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Tseng
authors.affiliation: Division of Pulmonary & Critical Care Medicine, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Department of Respiratory Therapy, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Meng-Chih
authors.initials: MC
authors.lastname: Lin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D056915:DNA Copy Number Variations; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D005978:Glutathione / Q000097:blood; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000235:genetics* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012907:Smoking
chemical_list: D004272:DNA, Mitochondrial; D005978:Glutathione