Isolation and characterization of glycosaminoglycans secreted by human foetal lung type II pneumocytes in culture.

All major glycosaminoglycans except keratan sulphate are found in animal lung and pleura (Wusteman, 1972). Pleural fluids from patients with several pulmonary diseases contain mostly hyaluronic acid (Friman, Hellstrom, Juvani & Riska, 1977). The high concentration of hyaluronic acid in pleural fluid associated with mesothelioma is considered diagnostic of this disease (Havez, Degand, Boersma & Richet, 1971). We have recently shown that hyaluronic acid is the only glycosaminoglycan detected in the pulmonary secretions of patients with asthma (Sahu & Lynn, 1978) and with pulmonary alveolar proteinosis (Sahu & Lynn, 1979). However, the cellular source of hyaluronic acid in these secretions is not known. A functional role for this secreted hyaluronic acid was recently identified to be directed specifically at alveolar macrophages (Love, Shannon, Myrvik & Lynn, 1977; Lynn & Mukherjee, 1979). Of particular interest are the secretions of the Type II pneumocytes, the metabolically active cells of the alveolar epithelium, which contribute to the production of alveolar secretions. Since we found hyaluronic acid but no other glycosaminoglycans in the alveolar secretions of patients with pulmonary alveolar proteinosis (Sahu & Lynn, 1979), it is possible that the alveolar Type II cells are the source of airway hyaluronic acid. The present report describes the isolation and characterization of glycosaminoglycans secreted by human foetal Type II pneumocytes in culture.