ABSTRACT
Introduction: Endogenous alphal-antitrypsin alpha is the main inhibitor of the intratracheally instilled elastase in experimental animals. Objective: To evaluate by electrophoresis and immunodetection using western blot analysis, the different forms of alpha1-AT in bronchoalveolar lavage fluid (BALF) of Sprague Dawley rats after intratracheal instillation of elastase, with the hypothesis that the previously observed increment in antielastase activity is due to high levels of active alpha1-AT. Results: In the first hours after elastase instillation the concentration of alpha1-AT increases more than seven times due to an increase in alveolar-capillary permeability. Alpha 1-AT in BAIF is found as the native protein (~ 52 kDa), as complexes of different molecular sizes (> 75 kDa and > 100 kDa) and as a proteolytic product (< 40 kDa). Conclusion: In spite of a high proportion of alpha1-AT in the inactive form as part of different complexes, the increase in alveolar-capillary permeability after elastase treatment contributes to maintain high levels of active alpha. These results could be of importance in other inflammatory lung processes.
Introducción: la antiproteasa alfa 1-antitripsina alfa constituye el principal inhibidor endógeno de la elastasa instilada por vía intratraqueal en modelos experimentales. Objetivo: Evaluar mediante electroforesis e inmunodetección por western blot, las distintas formas en que se encuentra la alfa1-AT en el lavado broncoalveolar (IBA) de ratas Sprague Dawley después de la instilación de elastasa, con la hipótesis de que el aumento en la actividad antielastasa previamente encontrada se acompaña de niveles altos de alfa1-AT activa. Resultados: En las primeras horas post-elastasa la concentración de alfa1-AT en el IBA aumenta más de 7 veces, debido al aumento de la permeabilidad alvéolo-capilar, encontrándose tanto como proteína nativa (~ 52 kDa), como parte de complejos de mayor tamaño (> 75 kDa y > 100 kDa) y como producto de proteólisis (< 40 kDa). Conclusión: A pesar de existir una alta proporción de alfa1-AT inactiva formando complejos, el aumento de la permeabilidad alvéolo-capilar contribuye a mantener niveles altos de alfa1-AT activa. Estos resultados podrían ser extrapolables a distintos procesos inflamatorios pulmonares.
Subject(s)
Animals , Rats , Capillary Permeability , Electrophoresis , Pancreatic Elastase/antagonists & inhibitors , Lung Diseases/metabolism , alpha 1-Antitrypsin/analysis , alpha 1-Antitrypsin/metabolism , Pulmonary Alveoli/enzymology , Blotting, Western , Bronchoalveolar Lavage , Disease Models, Animal , Lung Diseases/enzymology , Protease Inhibitors/metabolism , Rats, Sprague-Dawley , Time FactorsABSTRACT
The dynamic equilibrium of extracellular matrix (ECM) under different physiological conditions is a consequence of the balance between the regulation of synthesis and degradation of ECM components. Matrix metalloproteinases (MMPs), a family of structurally related zinc-dependent endopeptidases, are the physiological mediators of matrix remodeling. The expression and activity of these enzymes are highly regulated at several intra- and extracellular levels, so that in vivo enzymatic activity is the final result of a complex series of events including gene expression, zymogen activation, matrix binding, and enzymatic inhibition. MMPs are expressed at low levels in normal adult tissues, and their upregulation appears to play an important role in the development of a number of pathological processes. In acute lung injury, a disorder characterized by a severe disruption of the gas exchange alveolo-capillary structures, the upregulation of interstitial collagenase and gelatinases A and B strongly suggests that MMPs contribute to acute lung damage by facilitating the migration of inflammatory cells, as well as to the disruption of basement membrane components and extracellular matrix remodeling.
Subject(s)
Humans , Extracellular Matrix/enzymology , In Vitro Techniques , Lung Diseases/enzymology , Metalloproteases/metabolism , Collagenases/chemistry , Gelatinases/chemistry , Matrix Metalloproteinase 3/chemistry , Metalloproteases/classificationABSTRACT
The study has been conducted to find out the serum ADA levels in 120 patients with various pulmonary diseases which included patients with tubercular pleural effusion (n = 86), lung cancer (n = 10) and patients with non-tubercular pulmonary diseases like pneumonia, etc (n = 24). Twenty healthy individuals served as control subjects. The mean (+/- SD) of ADA activity was 23.38 (4.47), 7.29 (1.08), 12.71 (1.95) and 2.23 (1.00) units/litre in tuberculosis, malignancy, non-tubercular pulmonary diseases and healthy controls respectively with significant difference between each other (P less than 0.001). Patients with tuberculosis (100%) fall in 97% sensitivity range with a lower cut off limit at 17 units/litre ADA activity, while for malignancy and non-tubercular respiratory diseases, the sensitivity was 90% and 83% respectively. Within the sensitivity limits, the serum ADA activity can be used for the differential diagnosis of pulmonary diseases.