Chronic lung injury in preterm lambs: disordered pulmonary elastin
deposition.
Pierce, Richard A, Kurt H Albertine, Barry C Starcher, John F
Bohnsack, David P Carlton, and Richard D Bland.
Department of Internal Medicine, Washington University School of
Medicine at Barnes-Jewish Hospital, St. Louis, MO 63110, Department
of Pediatrics, Division of Developmental Lung Biology, University of
Utah School of Medicine, Salt Lake City, UT 84132, Department of
Biochemistry, University of Texas, Tyler, TX 75710
APStracts 3:0209L, 1996.
Prolonged mechanical ventilation of premature neonates is often
associated with abnormal morphological development of the lung and
chronic lung disease, sometimes called bronchopulmonary dysplasia
(BPD). Impaired alveolar development is a hallmark of this disease.
To better understand the effects of mechanical ventilation on lung
elastin expression, we studied lung tissue from 10 preterm lambs
(gestation = 125 d; term =148 d) mechanically ventilated for 3-4
weeks at a respirator rate of 20 breaths/min and tidal volume of
15+/-5 ml/kg (n=5) or 60 breaths/min and tidal volume of 5+/-2 ml/kg
(n=5). Histopathology showed increased elastin accumulation and
abnormal morphological development in the ventilated groups.
Postmortem lung desmosine content was increased significantly in the
20 breaths/min group. Tropoelastin mRNA expression was increased in
both ventilated groups. In situ hybridization localized increased
tropoelastin mRNA expression to sites of accumulated elastin in
extended alveolar walls with scant, attenuated secondary crests. Lung
collagen content as assessed by the amount of hydroxyproline in lung
tissue, was similar to controls. These data suggest that excessive
production and accumulation of elastin is associated with chronic
lung injury from prolonged mechanical ventilation after premature
birth.
Received 21 May 1996; accepted in final form 15 October 1996.
APS Manuscript Number L145-6.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996