Endothelial and epithelial sources of endothelin-1 in sheep
bronchi.
Mariassy, Andrew T., Marilyn K. Glassberg, Matthias Salath[acute]e,
Francis Maguire, and Adam Wanner.
Division of Pulmonary Disease, Department of Medicine, University
of Miami School of Medicine, Miami, Florida
APStracts 2:0140L, 1995.
Airway smooth muscle tone and growth is regulated by endothelin-1 (ET
-1) but the sources of ET-1 in the airway wall have not been clearly
defined. We therefore wished to estimate the relative contributions
of the epithelium and endothelium to ET-1 production in the bronchi
(mean ID 1.7-4.9 mm) of mature normal sheep. Morphometric assessment
of bronchial cross-sections revealed a 3 times greater number of
epithelial cells than endothelial cells by direct cell count. In
contrast, the overall cell surface density was 5-6 times greater and
the airway smooth muscle centered cell surface density 3-4 times
greater for endothelial cells than epithelial cells. The expression
of preproendothelin-1 mRNA was detected in cultured aortic
endothelial cells (as a substitute for bronchial endothelial cells)
but not in cultured bronchial epithelial cells, and the former
secreted 7 times more immunoreactive ET-1 than the latter. These
findings show that topographically the endothelium is better
positioned for the regulation of ovine bronchial smooth muscle than
the epithelium. Furthermore, the findings suggest greater
constitutive ET-1 secretion by cultured endothelium than epithelium.
Received 25 January 1995; accepted in final form 27 July 1995.
APS Manuscript Number L22-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 14 August 1995.