Hydrolytic enzyme of the alveolar macrophage in diffuse pulmonary interstitial disease

Abstract

Hydrolytic enzymes [acid phosphatase, beta-glucuronidase, beta-D-N-acetyl glucosaminidase (beta-D-NAGA), lysozyme and angiotensin-converting enzyme (ACE)] are the major constituents of alveolar macrophages (AM). These enzymes play a crucial role in the pathogenesis of interstitial lung diseases. Cell-associated activity of several enzymes in alveolar macrophages obtained from control subjects (n = 5) and patients suffering five representative types of interstitial pulmonary diseases [sarcoidosis (n = 10), extrinsic allergic alveolitis (n = 5), idiopathic pulmonary fibrosis (n = 5), neoplastic infiltration of the lung (n = 5) and Pneumocystis carinii pneumonia (n = 5)] were evaluated. Cells were obtained by bronchoalveolar lavage and isolated by Ficoll-Hypaque gradient. Enzymatic activity was assessed by standardized tests. Bronchoalveolar lavage (BAL) lymphocyte counts were significantly elevated in the patients with active sarcoidosis (median: 57%), allergic extrinsic alveolitis (median: 51%) and neoplastic infiltration (median: 31%) as compared with the other groups, whereas BAL neutrophil and eosinophil counts were significantly elevated in the patients with idiopathic pulmonary fibrosis (neutrophil median: 29%; eosinophil median: 3%). The highest alveolar macrophage enzymatic activities were obtained in the active sarcoidosis group (median ACE: 23.38 microKat 10(-6) AM; median lysozyme: 8.64 nKat 10(-6) AM; median beta-glucuronidase: 324.22 U 10(-6) AM; median acid phosphatase: 0.78 nKat 10(-6) AM; median beta-D-NAGA: 1.85 nKat 10(-6) AM) which was significantly greater than in the control group (median ACE: 6.69 microKat 10(-6) AM; median lysozyme: 1.95 nKat 10(-6) AM; median beta-glucuronidase: 39.88 U 10(-6) AM; median acid phosphatase: 0.38 nKat 10(-6) AM; median beta-D-NAGA: 0.44 nKat 10(-6) AM). However, intracellular lysosomal enzymatic activities of alveolar macrophages from patients with allergic extrinsic alveolitis, a disease in which the degree of alveolar macrophage activation is maximal, were similar to those of the control group. These findings demonstrated a different pattern of expression of alveolar macrophage's hydrolytic enzymes in lymphocytic diffuse pulmonary interstitial disease. In sarcoidotic patients, hydrolytic enzymes were increased whereas in allergic extrinsic alveolitis, hydrolytic enzyme activities were similar to control groups. Indirect data suggest that the release of lysosomal enzymes by alveolar macrophages during allergic extrinsic alveolitis may be a factor involved in the pulmonary lesions appearing in this disease.

Biochemical Characterization of Endogenously Formed Eosinophilic Crystals in the Lungs of Mice

“…Therefore, it would not be unexpected to find chitinase-like proteins in association with the overproduction of such acute phase reactants, particularly in the context of pulmonary injury of the me v /me v mice. Alveolar macrophages from pulmonary interstitial disease have increased hydrolytic enzymatic activity including ␤-D-N-acetyl glucosaminidase (36). The progressive lung disease in me v /me v mice is similar to that observed in patients with chronic interstitial lung disease; therefore, proliferating alveolar macrophages may be a source of enzymatically active Ym1 in mice.…”

Role of CXCR2 in cigarette smoke-induced lung inflammation

“…1, D and E). Levels of ␤-glucuronidase, one of several hydrolytic enzymes found in phagocytic cells and thought to play a role in tissue breakdown in inflammatory lung disease (27), were elevated 96% in the BAL of cigarette smoke-exposed mice. ␤-Glucuronidase activity was elevated 71% in SCH-N treated, smoke-exposed mice compared with nonsmoke-exposed controls, representing a 26% reduction in smoke exposure-specific activity (Fig.…”

Human bronchoalveolar lavage fluid: Two-dimensional gel electrophoresis, amino acid microsequencing and identification of major proteins

“…Like these cells, alveolar type II epithelial cells have been reported to show positivity for cathepsin D [32], superoxide dismutase [33] and ubiquitin [34]. Lysozyme, a hydrolytic enzyme, is a major constituent of alveolar macrophages [35]. Its release in the BAL fluid may reflect its involvement in the pulmonary lesions appearing in different diseases, e.g., allergic extrinsic alveolitis [35].…”

“…Lysozyme, a hydrolytic enzyme, is a major constituent of alveolar macrophages [35]. Its release in the BAL fluid may reflect its involvement in the pulmonary lesions appearing in different diseases, e.g., allergic extrinsic alveolitis [35]. Peptidyl-prolyl cis-trans isomerase B (PPIB) was also observed in BAL fluid: this protein was identified in three spots by N-terminal sequencing.…”