Kinetics of the inhibition of leukocyte elastase by the bronchial inhibitor.

The rate constant for the association between human leukocyte elastase (EC 3.4.21.11) and human bronchial inhibitor has been determined by competition experiments with alpha 1-proteinase inhibitor. This constant (1.1.10(7) M(-1) . s(-1)) is 6-times lower than that for the association of leukocyte elastase and alpha 1-proteinase inhibitor. The latter inhibitor is able to dissociate the leukocyte elastase-bronchial inhibitor complex with a rate constant 1.3.10(-4) s-1. The equilibrium dissociation constant Ki of the complex is 1.2.10(-11) M. The physiopathological significance of these constants is discussed.

Interaction of granulocyte proteases with inhibitors in pulmonary diseases.

The elastase-antielastase hypothesis of lung tissue destruction has focused our interest on the two main inhibitors of granulocyte elastase in the lung, alpha 1-antitrypsin dominating blood, interstitial tissue and alveolar fluid lining and antileukoprotease dominating the respiratory tract mucosa. Antileukoprotease as well as elastase and alpha 1-antitrypsin show increased serum levels during bronchitis and bronchopneumonia, alpha 1-antitrypsin because it is an acute phase reactant, elastase and antileukoprotease because of influx from the inflamed tissues. Elastase is identified in the bronchial expectorates, mainly in complex with antileukoprotease, but often also in a free, active form. The granulocyte elastase in serum from these patients is, however, only found in complex with alpha 1-antitrypsin. The increased amounts of antileukoprotease in serum are always in a free and largely active form. The explanation for the absence of elastase-antileukoprotease complexes in serum is offered by some of our recent results. The elastase-antileukoprotease complexes are rapidly dissociated when mixed with serum in vitro, although the equilibrium dissociation constant Ki of the complex is 1.2 X 10(-11) M. Furthermore, in a pure in vitro system, alpha 1-antitrypsin is able to dissociate a leukocyte elastase-antileukoprotease complex with the rate constant of 1.3 X 10(-4) X S-1. A small part of the antileukoprotease released from the elastase-antileukoprotease complex on mixture with serum is recovered bound by elastase-alpha 2-macroglobulin complexes. Antileukoprotease inhibits the enzymatic activity of elastase-alpha 2-macroglobulin complex relatively slowly. 1:1 elastase-alpha 2-macroglobulin complexes are, however, inhibited more readily than 2:1 saturated complexes.

Distribution of antileukoprotease in upper respiratory mucosa.

Human respiratory tract secretions contain enzyme inhibitors derived from plasma and a low molecular weight, acid-stable protease inhibitor, antileukoprotease. The distribution of antileukoprotease in normal upper respiratory tract mucosa has been studied using an immunohistologic technique. The inhibitor was localized to the serous parts of the submucosal glands of the maxillary sinus and the trachea but was not demonstrable in mucous glands and goblet cells. It is concluded that the antileukoprotease found in respiratory tract secretions is produced locally in the submucosal serous glands.

Localisation of secretory leucocyte proteinase inhibitor mRNA in nasal mucosa.

Human secretory leucocyte proteinase inhibitor (SLPI) is a low-molecular weight, acid-stable inhibitor of polymorph-nuclear granulocyte elastase and cathepsin G. Previous reports have demonstrated the existence of SLPI in the respiratory tract, salivary glands and cervical mucosa. Positive staining for SLPI using immunohistochemical techniques has been reported in serous glands in nasal mucosa. We now confirm this observation and show, using in situ hybridization, that the pattern of expression of mRNA corresponds to the distribution of the encoded protein, SLPI. This, together with the high concentration of SLPI in nasal secretions, confirms the hypothesis of a local production of SLPI in the mucous membranes.

Localization of antileukoprotease in the parotid and the submandibular salivary glands.

Antileukoprotease is the dominating inhibitor of granulocyte elastase and cathepsin G in normal human mixed and parotid saliva. The distribution of antileukoprotease in the submandibular and parotid glands was analysed with an immunoperoxidase technique using specific antibodies against antileukoprotease. Antileukoprotease was demonstrated in the serous cells of both the submandibular and parotid glands. These findings suggest that there is a local production of the inhibitor in the parotid gland and submandibular gland and are in agreement with our previous work which demonstrated high concentrations of the inhibitor in parotid saliva.

The mucosal defence capacity against proteolytic leukocyte enzymes.

Antileukoprotease is an important inhibitor of leukocyte elastase and seems to be the primary defence factor against elastase in the respiratory tract. The circulating level of antileukoprotease increases in inflammatory diseases and seems to be related to the degree of inflammation of the lung parenchyma. Antileukoprotease cannot be included among the general acute phase reactants as it does not increase in connection with surgical trauma.

A new administration form of the nasal decongestant oxymetazoline: a study on the change of ostial patency in healthy individuals.

A new administration form of the nasal decongestant oxymetazoline and the effect on patency of the maxillary ostium was investigated in five healthy volunteers. Registration and comparison of the equivalent diameter after administration of placebo spray and oxymetazoline spray, placebo solution and oxymetazoline solution were performed. It is our impression that administration of solution with the new spring-bellows container compared to spray oxymetazoline, is a more effective way of increasing the equivalent diameter of the maxillary ostium.

Antileukoprotease in patients with maxillary sinusitis.

Antileukoprotease, an inhibitor of leukocyte elastase, was studied in paired sera from 12 patients with maxillary sinusitis. The serum concentration of antileukoprotease was increased at the day of admission to hospital, compared with the serum concentration in convalescence sera. In purulent maxillary sinus secretions antileukoprotease was found in complex with leukocyte elastase, as shown by gel filtration. The findings suggest a local protective function of antileukoprotease in maxillary sinus.

Secretory leukocyte protease inhibitor in normal, allergic and virus induced nasal secretions.

Secretory leukocyte protease inhibitor (SLPI) and alpha-1-proteinase inhibitor (alpha-1-PI), both inhibitors of granulocyte elastase, were studied in nasal secretions from healthy persons and from patients with allergic rhinitis and common cold. SLPI and granulocyte elastase were found in all samples, while alpha-1-PI was lacking in several. In all three groups SLPI was found in an active form and in excess of granulocyte elastase, which thus was completely inhibited. The results indicate that SLPI is the main inhibitor in nasal secretions and that alpha-1-PI plays a minor role.

Is there a relationship between the degree of nasal obstruction and snoring?

The possible connection between snoring and nasal obstruction was studied in three groups of adult patients. In group 1, comprising 112 unselected patients, 36% snored, and 50% of the snorers suffered from nasal obstruction. The other two groups consisted of selected patients: group 2 (n = 41) and group 3 (n = 40) all of whom suffered from nasal obstruction. In group 2 nasal airway resistance was normal both before and after decongestant treatment, and in group 3 nasal airway resistance was pathologically high even after decongestant treatment. No difference was found between groups 2 and 3 regarding snoring. Sixty-six per cent in group 2 and 78% in group 3 snored. There was a correlation between snoring and the subjective nasal obstruction, but none between snoring and the degree of nasal obstruction expressed as nasal airway resistance.

The effect of cigarette smoke condensate on alpha 1-antitrypsin, antileukoprotease and granulocyte elastase.

Unfractionated cigarette smoke condensate was found to affect alpha 1-antitrypsin and antileukoprotease, which are the dominating enzyme inhibitors in the respiratory tract. The electrophoretic and crossed immunoelectrophoretic precipitate patterns of these inhibitors were grossly altered and their inhibiting capacity reduced in both a dose and time dependent way. Other plasma proteins were also affected by cigarette smoke condensate, which in high concentrations caused precipitation of most serum proteins. Human granulocyte elastase was reduced in functional activity by similar concentrations of the smoke condensate as the inhibitors. Although the elastolytic activity was markedly reduced, the esterolytic activity was reduced to a lesser degree.

The mucosal defence capacity against proteolytic leukocyte enzymes.

Proteolytic enzymes are released from granulocytes in connection with normal turnover and phagocytosis. Interest has been focused on granulocyte elastase as it has been shown to be associated with the development of lung emphysema. Elastase is present in purulent bronchial secretions where it is the dominating cause of elastolytic activity. The dominating inhibitors of elastase in the respiratory tract are alpha 1-antitrypsin and antileukoprotease. Antileukoprotease, which seems to be locally produced, is a potent inhibitor of elastase and accounts for about 90% of the inhibiting capacity against elastase. A local protective function of antileukoprotease is suggested by the finding that antileukoprotease was bound to granulocyte elastase in purulent bronchial secretions. The function of alpha 1-antitrypsin and antileukoprotease is reduced by the addition of smoke condensate in a dose- and time-dependent way. Smoke condensate was also found to depress the enzymatic activity of granulocyte elastase. Further studies of the protease-antiprotease balance in bronchial secretions from smokers with and without airway disease are necessary before any conclusions can be drawn regarding the pathophysiological significance of these results.

Studies on the role of antileukoprotease in respiratory tract diseases.

Antileukoprotease, an inhibitor of granulocyte elastase, was studied in paired sera from 19 patients with pneumonia and from 9 patients with cholecystolithiasis. The circulating level of antileukoprotease was significantly higher in patients with pneumonia compared with patients with cholecystolithiasis. In the latter group, surgery raised the level of general acute phase reactants, but did not affect the level of antileukoprotease. In sera from patients with pneumonia, antileukoprotease was recovered in a free and active form, as shown by gel-filtration of sera before and after the addition of leukocyte elastase. A local protective function of antileukoprotease is suggested by the finding that antileukoprotease was bound to granulocyte elastase in purulent bronchial secretions.

Studies on the interaction between leukocyte elastase, antileukoproteinase and the plasma proteinase inhibitors alpha 1-proteinase inhibitor and alpha 2-macroglobulin.

The dominating inhibitor of leukocyte elastase in human respiratory tract secretions is a low molecular mass inhibitor, designated antileukoproteinase. An equimolar antileukoproteinase-elastase complex was produced and subjected to gel filtration after differing time intervals and was found to be stable. On addition to human serum, however, elastase dissociated from antileukoproteinase and formed a complex with alpha 1-proteinase inhibitor. A small amount of elastase was also found bound to alpha 2-macroglobulin. Antileukoproteinase was capable of inhibiting elastase bound to alpha 2-macroglobulin. This inhibition was more complete and more rapid when the alpha 2-macroglobulin-elastase complex was in a molar ratio of 1:1 than in a ratio of 1:2.

A radioimmunoassay for measurement and characterization of human antileukoprotease in serum.

This report describes a radioimmunological method for the measurement of the protease inhibitor antileukoprotease in nanogram quantities. Antileukoprotease, previously found in bronchial secretions, has now also been found in serum using this radioimmunologic technique. In healthy blood donors the serum level was 126 micrograms/l. The serum immunoreactive antileukoprotease was found in a free form and did not show any antigenic cross reaction with the normal plasma protease inhibitors. Further, it was also found to be active and to form a complex with active human granulocyte elastase.