Enzyme levels in bronchoalveolar lavage fluid and serum of active pulmonary tuberculosis patients

Aminopeptidases in visceral organs during alterations in body fluid volume and osmolality

Enzymatic cleavage of some peptides in the local environment could be included among the mechanisms related to the regulation of hydrosaline balance. In order to examine this hypothesis, we measured representative aminopeptidase activities in visceral organs of rats after applying certain hydrosaline challenges. Decreased levels (about 30%) of particulate puromycin-insensitive-neutral aminopeptidase in the renal medulla and of soluble acid aminopeptidase in the lung were observed under hyperosmolality and hypovolemia. Decreased levels (more than 45%) of particulate type-I-pyroglutamyl aminopeptidase in the heart were observed under altered volemia. These results indicate that aminopeptidases at these anatomical locations might be involved in the regulation of body fluid volume and osmolality.

Specific enzyme activities in bronchoalveolar lavage fluid as an aid to diagnosis of tracheobronchitis and bronchopneumonia in dogs

Lactate dehydrogenase (LDH), alkaline phosphatase (ALP), alanine aminotransferase and gamma-glutamyl transferase enzyme activities, and total protein (TP), calcium, inorganic phosphate, urea nitrogen (UN) and creatinine concentrations in bronchoalveolar lavage fluid were investigated for their relative importance in the diagnosis of respiratory diseases in dogs. Bronchoalveolar lavage (BAL) fluid was obtained from 26 dogs (20 with respiratory diseases and six controls) following anaesthesia with sodium pentothal. Enzyme activities and biochemical parameters were measured in BAL fluid. LDH and ALP levels were significantly increased in 12 dogs with bronchopneumonia, but not in eight dogs with tracheobronchitis. Insignificant and variable levels of TP and UN concentrations were found in both groups. It was concluded that LDH and ALP enzyme activities could be considered as pointers to pulmonary inflammation and/or damage while TP and UN measurements in BAL fluid may have a place in the identification of changes in respiratory and vascular permeability.

Hydrolytic enzyme of the alveolar macrophage in diffuse pulmonary interstitial disease

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.

Urinary excretion of renal brush border membrane enzymes in leprosy patients--effect of multidrug therapy

Renal function at the brush border membrane level has been studied using characteristic enzymes, such as alkaline phosphatase, leucine-aminopeptidase and gamma-glutamyl transpeptidase. Urinary enzyme studies were performed using leprosy patients, classified on the basis of bacteriological index (BI>3; n=20, BI<3; n=12, BI-ve; n=10) and compared with control subjects (n=10). The role of enzymuria in monitoring WHO-recommended multidrug therapy (MDT) has been evaluated in these patients. A significant increase in the enzyme activities (p<0.01), as well as significant (p<0.01) proteinurea in 24-hour urine samples of both the smear positive groups (BI>3, BI<3) prior to therapy compared to control subjects, indicates proximal tubular functional impairment at brush border membrane level. In the smear negative (BI-ve) group, no significant difference was observed in enzyme activities as compared with the control group. In a follow-up study (BI>3;n=13, BI<3; n=4) the activities of all the enzymes decreased significantly in all the groups when compared to a corresponding untreated group. The follow-up study was not carried out on the smear negative group. The surprising finding was the differential behaviour of r-glutamyl transpeptidase, whose activity increased significantly (p<0.01) even after therapy in BI>3 group when compared with untreated patients. However in a detailed work-up including hepatic and renal function tests, the serum biochemistry was found to be normal both before and after therapy. Urinary excretion of brush border enzymes seems to be related to bacterial load, and their potential in studying the effect of MDT remains unclear.

Role of lysosomal enzymes released by alveolar macrophages in the pathogenesis of the acute phase of hypersensitivity pneumonitis

Hydrolytic enzymes are the major constituents of alveolar macrophages (AM) and have been shown to be involved in many aspects of the inflammatory pulmonary response. The aim of this study was to evaluate the role of lysosomal enzymes in the acute phase of hypersensitivity pneumonitis (HPs). An experimental study on AM lysosomal enzymes of an HP-guinea-pig model was performed. The results obtained both in vivo and in vitro suggest that intracellular enzymatic activity decrease is, at least partly, due to release of lysosomal enzymes into the medium. A positive but slight correlation was found between extracellular lysosomal activity and four parameters of lung lesion (lung index, bronchoalveolar fluid total (BALF) protein concentration, BALF LDH and BALF alkaline phosphatase activities). All the above findings suggest that the AM release of lysosomal enzymes during HP is a factor involved, although possibly not the only one, in the pulmonary lesions appearing in this disease.