Idiopathic Pulmonary Fibrosis: Abnormalities in Bronchoalveolar Lavage Fluid Phospholipids

Abstract

Bronchoalveolar lavage has been used to sample cells and proteins in the distal lung. One of the major secretory products of the alveolar type II epithelial cells, pulmonary surfactant, can be recovered by lavage. Abnormalities in alveolar type II cells are found in biopsies of patients with idiopathic pulmonary fibrosis (IPF), and abnormalities of pulmonary surfactant phospholipids have been reported after diffuse lung injury in animals and in humans. Therefore, we questioned if abnormalities in lavage phospholipids might also occur in IPF, a chronic inflammatory disease of the alveolar epithelium and interstitium, and, if present, would these abnormalities reflect histopathologic changes or predict responsiveness to therapy. Fifteen untreated patients with IPF, diagnosed by open lung biopsy, were studied and were found to have less than half the amount of bronchoalveolar lavage phospholipid as that recovered from healthy volunteers (p less than 0.05). In addition, patients with IPF had a lower proportion of phosphatidylglycerol and a higher proportion of phosphatidylinositol in the recovered phospholipids than did healthy volunteers (p less than 0.05). The severity of these alterations in phospholipid composition correlated with more advanced fibrotic histopathologic changes. Patients with less depression of total phospholipids in lavage improved with corticosteroid therapy, whereas the patients with more severely decreased total phospholipid recovered in lavage did not.

Age-dependency of surfactant phospholipids and surfactant protein A in bronchoalveolar lavage fluid of children without bronchopulmonary disease

“…Recent studies utilizing bronchoalveolar lavage (BAL) have demonstrated that the total phospholipid concentrations as well as the ratio of phophatidylglycerol to phosphatidylinositol (PG/PI) are decreased in patients with the adult respiratory distress syndrome [3,4] and in respiratory failure due to trauma [5,6]. A reduction in the PG/PI ratio has also been observed in a variety of interstitial lung diseases [7][8][9]. Total phospholipid concentrations of bronchoalveolar lavage fluid (BALF) have been found to be diminished in patients with acquired immune deficiency syndrome (AIDS) both with and without Pneumocystis carinii pneumonia [10,11].…”

Hypertrophy and Hyperplasia of Alveolar Type II Cells in Response to Silica and Other Pulmonary Toxicants

“…Very few studies have examined Lype II cell function under conditions of naturally occurring or chemically induced lung disease. Perturbations of the surfactant system accompany a number of human respiratory conditions, including the neonatal and adult respiratory distress syndromes (4,5), idiopathic pulmonary fibrosis (6), and alveolar proteinosis (7,8), but the causes of the surfactant abnormalities and their relationship to the progression of disease have not been delineated. In addition, in experimental animals, alterations in surfactant levels have been reported following exposure of the lung to a variety of chemical and physical agents, suggesting that Type II cells and the surfactant system may be important components in the response ofthe lung to irnury.…”

Minerals, Fibrosis, and the Lung

“…A limited degree of lipidosis may then determine the induction ofdiffuse interstitial fibrosis instead of the focal or circumscribed forms of dust lesions characteristic of simple silicosis, coal workers' pneumoconiosis and asbestosis (316). Human pulmonary interstitial fibrosis affords a comparable situation, since the more severe fibrotic features were associated with a reduction ofphospholipid in bronchoalveolar lavage fluid (317). The proposal that surface radicals exposed on freshly fractured particles of crystalline silica are implicated in the genesis ofaccelerated silicosis (318) or that such radicals account for pulmonary injury by fresh coal mine dust (205) …”