Pulmonary penetration of alpha 1-proteinase inhibitor administered parenterally to dogs

Pulmonary deposition and clearance of aerosolized alpha-1-proteinase inhibitor administered to dogs and to sheep

Augmentation of lung antiprotease levels may be an important therapeutic intervention in the prevention of pulmonary emphysema. We have administered aerosols of plasma-derived human alpha 1 proteinase inhibitor (A1PI) to the lungs of dogs and sheep to investigate (a) delivery of the protein to the distal air spaces of the lung; (b) maintenance of functional activity of the protein; and (c) flux of the protein across the components of the alveolar-capillary membrane. A1PI (26.4 mg/kg body weight) was administered as an aerosol to anesthetized animals; sheep were prepared for the chronic collection of lung lymph. Immunoperoxidase staining of lung tissue obtained 2 h after administration of A1PI demonstrated the presence of human A1PI on the surface of alveoli and distal bronchioles. Bronchoalveolar lavage fluid recovered at intervals after A1PI administration demonstrated time-dependent elevations of human A1PI levels with augmentation of lavage fluid antielastase activity in proportion to the content of human A1PI. Using radiolabeled A1PI as a tracer, we found that 32% of the aerosol was retained in the animals' lungs. Measurements of the rate of loss of A1PI from the lung and of the rate of appearance of human A1PI in plasma resulted in a calculated permeability of the alveolar-capillary membrane to A1PI of 3.49-6.39 X 10(-10) cm/s. Experiments using instrumented sheep allowed independent calculation of endothelial permeability to A1PI of 122-236 X 10(-10) cm/s and calculation of epithelial permeability of 4.70-4.81 X 10(-10) cm/s. Modeling of aerosol delivery of A1PI to humans using the results of these studies predicts that the ratio of plasma/alveolar levels of delivered A1PI will be 0.024, and that aerosolization of 175 mg A1PI/d will result in an A1PI alveolar fluid level of 1.0 mg/ml. Aerosol administration of A1PI may provide an efficient method of augmenting alveolar antiprotease levels.

Intravenous administration of alpha-1-proteinase inhibitor in patients of PiZ and PiM phenotype. Preliminary report

Nine patients with moderate pulmonary emphysema, six of PiZ phenotype and three of PiM phenotype, have received a single intravenous infusion of alpha-1-proteinase inhibitor (human) (A1PI), in a dose of 60 mg/kg over a 30-minute period. They also received a tracer dose (300 microCi) of 131I-labeled A1PI. No active or passive immunization against hepatitis was given. No acute toxicity was observed. Compared with baseline data, significant elevations of serum A1PI (measured both antigenically and as anti-elastase activity) occurred, with a serum half-life approximating 110 hours. Bronchoalveolar lavage fluid, obtained 48 hours after infusion, reflected a significant increase in A1PI concentration versus baseline bronchoalveolar lavage fluid values. Serial gamma camera images of the lungs confirmed persistence of enhanced lung radioactivity for several days. Urinary desmosine excretion did not change following A1PI infusion. During the period of follow-up thus far, no patient has had chronic toxicity, results of liver function tests have been stable, and there has been no development of hepatitis B antigen or antibodies to hepatitis B surface or core antigens.