title: Elevated levels of IL-18 in plasma and skeletal muscle in chronic obstructive pulmonary disease.
abstract: The aim of this study was to test the hypothesis that systemic inflammation in patients with chronic obstructive pulmonary disease (COPD) is accompanied by enhanced interleukin 18 (IL-18) expression in skeletal muscle, which may precede muscle weight loss. Twenty patients with moderate to severe COPD [12 women, 66 +/- 9.4 years of age and forced expiratory volume in 1 second (FEV(1)) of 32% +/- 12 % of predicted value] and 20 healthy age-, gender-, and body mass index (BMI)-matched controls (10 nonsymptomatic smokers and 10 nonsmokers) were included in the study. Plasma levels of IL-18 were elevated in COPD patients (n = 20) versus healthy controls (n = 20) (221.2 pg/ml [196.0-294.2 pg/pl] vs. 164.8 pg/ml [144.4-193.3 pg/pl], p = 0.05) [corrected] and IL-18 was expressed in skeletal muscle, with IL-18 mRNA levels being elevated in biopsies from COPD patients (n = 19) versus healthy controls (n = 18) (4.3 [2.6-5.9] vs. 2.4 [1.6-3.1], p = 0.05) [corrected]. Immunohistochemical evaluation revealed a strong expression of IL-18 in Type II muscle fibers from COPD patients. Plasma levels and skeletal muscle mRNA levels of tumor necrosis factor alpha (TNF-alpha) and IL-6 did not differ between the groups. Elevated skeletal muscle expression of IL-18 was found in COPD patients with normal body weight, indicating that IL-18 potentially may be involved in the pathogenesis of COPD-associated muscle wasting.
authors: The Centre of Inflammation and Metabolism, Department of Infectious Diseases, The Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors: A M W
authors: AM
authors: Petersen
authors: M
authors: M
authors: Penkowa
authors: M
authors: M
authors: Iversen
authors: L
authors: L
authors: Frydelund-Larsen
authors: J L
authors: JL
authors: Andersen
authors: J
authors: J
authors: Mortensen
authors: P
authors: P
authors: Lange
authors: B K
authors: BK
authors: Pedersen
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D001706:Biopsy; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020382:Interleukin-18 / Q000097:blood* / Q000235:genetics; D015850:Interleukin-6 / Q000097:blood / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood; D012129:Respiratory Function Tests; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000235:genetics / Q000378:metabolism
chemical_list: D020382:Interleukin-18; D015850:Interleukin-6; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha