The elastase inhibitory capacity and the alpha 1-proteinase inhibitor and bronchial inhibitor content of bronchoalveolar lavage fluids from healthy subjects.
Pulmonary emphysema is currently thought to be due to an elastase-antielastase imbalance with resultant destruction of alveolar structures. The present study was aimed at testing whether alpha 1-proteinase inhibitor (alpha 1 PI) is the major component of the antielastase screen of the lower respiratory tract of healthy subjects. Bronchoalveolar lavage was performed in 8 nonsmokers (27.8 +/- 3.8 years) and 9 smokers (25 +/- 0.96 years). The lavage fluids were tested for leukocyte and pancreatic elastase inhibitory capacity (LEIC and PEIC) and immunoreactive alpha 1 PI and bronchial inhibitor (brI) content. The mean +/- s.e.m. levels of LEIC, PEIC, alpha 1 PI and brI were 0.16 +/- 0.039, 0.042 +/- 0.006, 0.09 +/- 0.007 and 0.013 +/- 0.002 mol/mol albumin, respectively. Thus, on the average, the molar concentration of brI was about 14% that of alpha 1 PI. The difference between LEIC and alpha 1 PI did not reach statistical significance (P = 0.0503). The PEIC was however significantly lower than the alpha 1 PI levels (P less than 0.05), indicating that the lavage fluids contained both active and inactive alpha 1 PI. Nonsmokers and smokers did not differ in their LEIC, PEIC, alpha 1 PI and brI levels. When the data were examined on an individual basis, the subjects could be divided into 2 groups: group I (n = 9; 3 nonsmokers, 6 smokers) whose LEIC/alpha 1 PI molar ratios were higher than unity and group II (n = 8; 5 nonsmokers, 3 smokers) whose LEIC/alpha 1 PI molar ratios were equal or lower than unity. Group I subjects had significantly higher LEIC values (0.26 +/- 0.05 mol elastase inhibited/mol albumin) than group II individuals (0.055 +/- 0.006; P less than 0.001) but the two groups had similar levels of immunoreactive alpha 1 PI (0.09 and 0.08 mol alpha 1 PI/mol albumin for group I and II, respectively), functionally active alpha 1 PI (percentage of active alpha 1 PI: 53% and 37% for group I and II, respectively) and immunoreactive brI (0.016 and 0.010 mol brI/mol albumin for group I and II, respectively). These results suggested that the lavage fluids from group I contained significant amounts of undefined leukocyte elastase inhibitor(s). Gel filtration of a lavage fluid from group I showed that the undefined elastase inhibitor(s) co-eluted with brI. Most of the lavage fluids were still able to inhibit leukocyte elastase following removal of alpha 1 PI by perchloric acid precipitation.(ABSTRACT TRUNCATED AT 400 WORDS)
Boudier
C
C
Laboratoire d'Enzymologie, INSERM Unité 237, Université Louis Pastuer, Strasbourg.
Pelletier
A
A
Gast
A
A
Tournier
J M
JM
Pauli
G
G
Bieth
J G
JG
D000328:Adult; D001798:Blood Proteins / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000201:enzymology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007120:Immunochemistry; D007163:Immunosorbent Techniques; D007962:Leukocytes / Q000201:enzymology; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D000515:alpha 1-Antitrypsin
D001798:Blood Proteins; D000515:alpha 1-Antitrypsin; D010196:Pancreatic Elastase