RESUMEN
To evaluate the possibility of administering therapeutic proteins via the respiratory route, we administered an aerosol of recombinant DNA-produced human alpha 1-antitrypsin (rAAT) to anesthetized sheep and measured levels of the protein in epithelial lining fluid (ELF), lung lymph, blood, and urine. Using a nebulizer that generated aerosol droplets with a mass median aerodynamic diameter of 2.7 micron (55% of droplets were less than 3 micron, a particle size optimal for deposition on the alveolar epithelium), in vitro studies demonstrated that the aerosolized rAAT remained intact and fully functional as an inhibitor of neutrophil elastase. When aerosolized to sheep, the 45-kDa rAAT molecule diffused across the alveolar epithelium, as evidenced by its presence in lung lymph and in blood. Comparison of ELF, lymph, blood, and urine rAAT levels demonstrated that the process was concentration dependent, with highest levels in ELF and in descending concentrations with approximately 10-fold concentration differences in each consecutive compartment, respectively. Importantly, evaluation with aerosolized 125I-labeled rAAT demonstrated that the rAAT molecules that reached the lung lymph and the systemic circulation remained intact as a 45-kDa protein. These results demonstrate the feasibility of using aerosolization to the pulmonary epithelial surface to administer sizeable proteins of therapeutic interest, thus circumventing the necessity of the traditional parenteral modes of administration of such molecules.
Asunto(s)
Pulmón/metabolismo , alfa 1-Antitripsina/administración & dosificación , Absorción , Administración por Inhalación , Aerosoles , Animales , Autorradiografía , Electroforesis en Gel de Poliacrilamida , Epitelio/metabolismo , Femenino , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/farmacocinética , Ovinos , alfa 1-Antitripsina/farmacocinéticaRESUMEN
Langerhans' cells are a defined subpopulation of the mononuclear phagocyte system known to accumulate in the lung in histiocytosis X, an interstitial lung disorder strongly linked to cigarette smoking. To evaluate the hypothesis that cigarette smoking itself may be associated with the accumulation of Langerhans' cells in the lung, normal nonsmokers (n = 5) and normal smokers (n = 10) were evaluated by bronchoalveolar lavage for the presence of Langerhans' cells as identified by the OKT6 monoclonal antibody and by transmission electron microscopy. While the OKT6 antibody identified 0.1 +/- 0.1% of the cells recovered from nonsmokers, it labeled 1.1 +/- 0.3% of those recovered from smokers (p less than 0.01). Furthermore, while electron microscopy demonstrated no Langerhans' cells among the lavage cells from nonsmokers, 0.4 +/- 0.1% of the cells recovered from normal smokers contained characteristic intracytoplasmic Birbeck granules, positively identifying them as Langerhans' cells. We conclude that cigarette smoking is associated with an expansion in the population of Langerhans' cells on the epithelial surface of the lower respiratory tract. While the mechanisms underlying this accumulation are unknown, it is possible that the properties of these cells contribute to the derangements of the pulmonary parenchyma found in cigarette smoking and establish a biologic link to the already observed epidemiologic association between histiocytosis X and cigarette smoking.
Asunto(s)
Células de Langerhans/inmunología , Pulmón/inmunología , Fumar/inmunología , Adulto , Anticuerpos Monoclonales/análisis , Líquido del Lavado Bronquioalveolar/citología , Líquido del Lavado Bronquioalveolar/inmunología , Epitelio/inmunología , Epitelio/ultraestructura , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Células de Langerhans/ultraestructura , Pulmón/ultraestructura , Masculino , Microscopía Electrónica , Valores de Referencia , Fumar/patologíaRESUMEN
S-type alpha 1-antitrypsin (alpha 1AT) is a deficiency haplotype that differs from the common normal M1 (val213) alpha 1AT haplotype by a single amino acid (glu264 to val264). To evaluate the adequacy of the antineutrophil elastase protection associated with the S homozygous state, alpha 1AT plasma and lung epithelial lining fluid (ELF) levels and antineutrophil elastase function were analyzed in 9 PISS subjects. The plasma alpha 1AT levels of SS subjects were intermediate between that of M1M1 and ZZ subjects (p less than 0.001, all comparisons) and the plasma neutrophil elastase inhibitory capacity paralleled the differences in alpha 1AT concentration (p less than 0.001, all comparisons). The association rate constant for neutrophil elastase of the purified S protein was less than that of the normal molecule (S-type, 7.1 +/- 0.1 X 10(6) M-1 s-1; M1-type, 9.6 +/- 0.2 X 10(6) M-1 s-1; p less than 0.001), but much greater than that for the Z molecule (p less than 0.001). Exposure of the purified S protein to increasing oxidant burdens resulted in a dose-dependent reduction in the ability of the molecule to inhibit neutrophil elastase in a fashion parallel to that of the M1 and Z proteins. Quantification of ELF alpha 1AT levels and antineutrophil elastase capacity demonstrated that the SS ELF parameters were, as in plasma, intermediate between M1 homozygotes and Z homozygotes. Using the association rate constant together with the quantification of ELF alpha 1AT levels, the "in vivo lung inhibition time" was estimated, yielding an assessment of the relative antineutrophil elastase screen of the PISS lower respiratory tract.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Neutrófilos/enzimología , Elastasa Pancreática/antagonistas & inhibidores , alfa 1-Antitripsina/farmacología , Adulto , Relación Dosis-Respuesta a Droga , Epitelio/análisis , Epitelio/metabolismo , Femenino , Haplotipos , Homocigoto , Humanos , Pulmón/análisis , Pulmón/metabolismo , Masculino , Oxidación-Reducción , Fenotipo , Enfisema Pulmonar/etiología , Enfisema Pulmonar/genética , Enfisema Pulmonar/metabolismo , Factores de Riesgo , Factores de Tiempo , alfa 1-Antitripsina/análisis , alfa 1-Antitripsina/genética , Deficiencia de alfa 1-AntitripsinaRESUMEN
To evaluate the potential use of recombinant DNA-produced alpha-1-antitrypsin (alpha-1-AT) to augment the lung antineutrophil elastase defenses in alpha-1-AT deficiency, we compared the kinetics of intravenously administered recombinant produced alpha-1-AT (r alpha-1-AT) and purified normal human plasma alpha-1-AT (p alpha-1-AT) in the blood and lung of rhesus monkeys. The r alpha-1-AT was produced in yeast transformed with an expressing plasmid containing a full-length human alpha-1-AT complementary deoxyribonucleic acid and purified to greater than 99% homogeneity. The r alpha-1-AT has a molecular weight of 45,000, no carbohydrates, and is identical in sequence to normal plasma alpha-1-AT except for an additional N-terminal acetylmethionine. Despite its lack of carbohydrates, the r alpha-1-AT inhibited human neutrophil elastase with an association rate constant similar to that of p alpha-1-AT. Rhesus monkeys were infused intravenously with 120 mg/kg of r alpha-1-AT (n = 13) or p alpha-1-AT (n = 12) and the serum, urine, and lung epithelial lining fluid (ELF) concentrations of these molecules quantified at various intervals.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Proteínas Sanguíneas/metabolismo , Líquido del Lavado Bronquioalveolar/metabolismo , Inhibidores de Proteasas/metabolismo , alfa 1-Antitripsina/farmacocinética , Animales , Electroforesis en Gel de Poliacrilamida , Epitelio/metabolismo , Semivida , Humanos , Pulmón/metabolismo , Macaca mulatta , Peso MolecularRESUMEN
In patients with alpha 1-antitrypsin deficiency, the development of emphysema is believed to be caused by the unchecked action of proteases on lung tissue. We evaluated the feasibility, safety, and biochemical efficacy of intermittent infusions of alpha 1-antitrypsin in the treatment of patients with alpha 1-antitrypsin deficiency. Twenty-one patients were given 60 mg of active plasma-derived alpha 1-antitrypsin per kilogram of body weight, once a week for up to six months. After a steady state had been reached, the group had trough serum levels of alpha 1-antitrypsin of 126 +/- 1 mg per deciliter as compared with 30 +/- 1 mg per deciliter before treatment, and serum anti-neutrophil elastase capacities of 13.3 +/- 0.1 microM as compared with 5.4 +/- 0.1 microM. The alpha 1-antitrypsin level in the epithelial-lining fluid of the lungs was 0.46 +/- 0.16 microM before treatment, and the anti-neutrophil elastase capacity was 0.81 +/- 0.13 microM. Six days after infusion, alpha 1-antitrypsin levels (1.89 +/- 0.17 microM) and anti-neutrophil elastase capacities (1.65 +/- 0.13 microM) in the lining fluid were significantly increased (P less than 0.0001). Because of the chronicity of the disorder and the lack of sensitive measures of lung destruction, the clinical efficacy of this therapy could not be studied rigorously. No changes in lung function were observed in our patients over six months of treatment. The only important adverse reactions to the 507 infusions were four episodes of self-limited fever. This study demonstrates that infusions of alpha 1-antitrypsin derived from plasma are safe and can reverse the biochemical abnormalities in serum and lung fluid that characterize this disorder. Together with lifetime avoidance of cigarette smoking, replacement therapy with alpha 1-antitrypsin may be a logical approach to long-term medical treatment.
Asunto(s)
Enfisema Pulmonar/tratamiento farmacológico , alfa 1-Antitripsina/uso terapéutico , Adulto , Estudios de Evaluación como Asunto , Femenino , Humanos , Infusiones Parenterales , Pulmón/enzimología , Masculino , Persona de Mediana Edad , Neutrófilos/enzimología , Elastasa Pancreática/antagonistas & inhibidores , Enfisema Pulmonar/etiología , Fumar , alfa 1-Antitripsina/administración & dosificación , Deficiencia de alfa 1-AntitripsinaRESUMEN
The null-null phenotype of alpha 1-antitrypsin (alpha 1AT), a phenotype characterized by no detectable alpha 1AT in serum, presents a rare opportunity to examine the contribution of alpha 1AT to the antineutrophil elastase protection of the lower respiratory tract. The subject, a 35-yr-old lifetime non-smoker with moderate emphysema, has been characterized as having alpha 1AT serum levels of zero resulting from the homozygous inheritance of alpha 1AT genes that do not express detectable alpha 1AT mRNA transcripts. Evaluation of the antineutrophil elastase capacity of the null-null serum showed it was less than 5% of normal, whereas that of the epithelial lining fluid (ELF) of the lower respiratory tract was 13% of normal. However, after 60 mg/kg of intravenously administered alpha 1AT augmentation therapy once weekly for 4 wk, the serum alpha 1AT levels peaked at greater than 300 mg/dl, trough levels just prior to the next infusion were 81 +/- 2 mg/dl, and the average serum level integrated for the month of infusions was 138 mg/dl. Consistent with this serum rise in alpha 1AT, the serum antineutrophil elastase capacity increased in parallel(r = 0.98). Importantly, evaluation of the ELF 2 and 6 days after infusion demonstrated increases of alpha 1AT levels (range, 1.4 to 2.1 microM) and antineutrophil elastase capacity (range, 1.6 to 2.5 microM), values within the lower range of normal. Furthermore, the lung ELF alpha 1AT levels rose in direct proportion to the serum alpha 1AT levels, and the ELF antineutrophil elastase capacity rose in direct proportion to the ELF alpha 1AT levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Sangre/metabolismo , Pulmón/metabolismo , Neutrófilos/enzimología , Elastasa Pancreática/antagonistas & inhibidores , alfa 1-Antitripsina/metabolismo , Adulto , Enfisema/sangre , Enfisema/enzimología , Enfisema/genética , Enfisema/metabolismo , Humanos , Pulmón/enzimología , Masculino , Fenotipo , Sistema Respiratorio/metabolismo , alfa 1-Antitripsina/genética , alfa 1-Antitripsina/uso terapéuticoRESUMEN
Tamoxifen, an agent that binds to intracytoplasmic estrogen receptors, was evaluated as a possible means of increasing alpha-1-antitrypsin (alpha 1AT) synthesis and/or secretion and thus alpha 1AT serum levels in subjects with the homozygous form of alpha 1AT deficiency. Administration of tamoxifen (10 mg twice daily) to 30 Z homozygotes for a 30-day period was not associated with adverse reactions. However, although serum alpha 1AT levels increased significantly (p less than 0.03), the increase was minor (average pretreatment levels, 32 +/- 1 mg/dl; levels at 30 days of therapy, 35 +/- 1 mg/dl) and far below the "threshold" level of 80 mg/dl considered "protective" against an increased risk for emphysema. Thus, while the concept that increasing alpha 1AT synthesis and/or secretion is a rational goal for treating the Z homozygous form of alpha 1AT deficiency, tamoxifen will not be useful in this regard.