Determination of low-molecular-mass antioxidant concentrations in human respiratory tract lining fluids

• Published in: American journal of physiology. Lung cellular and molecular physiology Vol. 276; no. 2; pp. 289 - L296
• Main Authors: van der Vliet, Albert, O'Neill, Charles A, Cross, Carroll E, Koostra, John M, Volz, William G, Halliwell, Barry, Louie, Samuel
• Format: Journal Article
• Language: English
• Published: United States 01.02.1999
• Subjects: Adolescent; Adult; Antioxidants - analysis; Antioxidants - chemistry; Body Fluids - chemistry; Bronchoalveolar Lavage Fluid - chemistry; Epithelium - chemistry; Female; Humans; Lung - chemistry; Male; Methods; Middle Aged; Molecular Weight; Nasal Mucosa - chemistry; Osmolar Concentration; Respiratory System - chemistry; Therapeutic Irrigation
• ISSN: 1040-0605; 0002-9513; 1522-1504
• DOI: 10.1152/ajplung.1999.276.2.l289

1  Division of Pulmonary/Critical Care Medicine, University of California, Davis Medical Center, Sacramento 95817; 2  Center for Comparative Respiratory Biology and Medicine, Department of Internal Medicine, University of California, Davis 95616; 3  Toxicology Department, Genentech, Inc., So. San Francisco, California 94080; and 4  Pharmacology Group, International Antioxidant Research Centre, King's College, London SW3 6LX, United Kingdom Antioxidants present within lung epithelial lining fluids (ELFs) constitute an initial line of defense against inhaled environmental oxidants such as ozone, nitrogen oxides, and tobacco smoke, but the antioxidant composition of human ELFs is still incompletely characterized. We analyzed ELF concentrations of the low-molecular-mass antioxidants ascorbate, urate, glutathione (GSH), and -tocopherol by obtaining bronchoalveolar lavage (BAL) and nasal lavage fluids from healthy nonsmoking volunteers and compared two different BAL procedures. ELF dilution by the lavage procedures was estimated by measurement of urea in recovered BAL fluids in comparison with those in blood plasma from the same subjects. The results indicated that a recently developed single-cycle BAL procedure minimizes influx of non-ELF urea into the instilled fluid and thus allows for a more accurate determination of ELF antioxidant concentrations. Using this procedure, we determined that bronchoalveolar ELF contains 40 ± 18 (SD) µM ascorbate, 207 ± 167 µM urate, 109 ± 64 µM GSH, and 0.7 ± 0.3 µM -tocopherol ( n  = 12 subjects). Similar analysis of nasal lavage fluid yielded nasal ELF levels of 28 ± 19 µM ascorbate and 225 ± 105 µM urate ( n  = 12 subjects), whereas GSH was undetectable (<0.5 µM). Our results demonstrate that ascorbate and urate are major low-molecular-mass ELF antioxidants in both the upper and lower respiratory tract, whereas GSH is present at significant concentrations only in bronchoalveolar ELF. bronchoalveolar lavage; nasal lavage; epithelial lining fluid; ascorbate; urate; glutathione; -tocopherol