[Pneumological diagnostics by means of models aerosols. IV. Clearance of aerosol particles from the pulmonary alveoli. Foundations and first clinical results].
The elimination of deposited particles (inorganic and organic particles, bacteria, viruses) from the periphery of the human lung (alveolar clearance) implies phagocytosis by alveolar macrophages, intracellular digestion, migration and translocation. Alveolar clearance of poorly soluble particles happens very slowly and primarily depends on the function of alveolar macrophages. In humans, the transport of particles to the bronchial tree is of secondary relevance, suggesting that the elimination of particles primarily depends on digestion (dissolution) processes within macrophages. The dissolved material is excreted via urine, if there is no further metabolization within the body. The pathophysiology of the alveolar clearance mechanisms in the human lung can be studied by a magnetic tracer technique (magnetopneumography). Ferromagnetic magnetite test-particles are deposited in the periphery of the lung by controlled inhalation. After magnetization and particle alignment in a strong external magnetic field pulse, the amount of retained particles can be detected by a sensitive magnetic field sensor (SQUID, superconducting quantum interference device). Long lasting cigarette smoking and chronic lung inflammations (sarcoidosis, interstitial lung fibrosis) induce a significant impairment of alveolar clearance capacity, while patients with chronic bronchitis show only a moderate impairment of alveolar clearance.
Möller
W
W
Klinische Kooperationsgruppe "Aerosolmedizin" des GSF Forschungszentrums für Umwelt und Gesundheit, Institut für Inhalationsbiologie, München-Gauting, Germany. moeller@gsf.de
Kohlhäufl
M
M
Häussinger
K
K
Heyder
J
J
D000336:Aerosols / Q000008:administration & dosage / Q000493:pharmacokinetics; D006801:Humans; D016676:Macrophages, Alveolar / Q000502:physiology; D008280:Magnetics; D008657:Metabolic Clearance Rate; D011650:Pulmonary Alveoli / Q000502:physiology*
D000336:Aerosols