Enhanced alveolar type ii cell growth on a pulmonary extracellular
matrix over fibroblasts.
Adamson, I. Y. R., L. Young, and J. Bakowska.
Department of Pathology, University of Manitoba, Winnipeg,
Canada
APStracts 3:0201L, 1996.
The growth of alveolar Type II cells was studied when these cells were
maintained two days on a pulmonary endothelial derived extracellular
matrix (ECM) on a filter with or without lung fibroblasts in the
lower chambers of culture wells. Type II cell proliferation was
enhanced by the ECM as compared to other substrates but was
significantly higher still with fibroblasts beneath. This was
determined by thymidine uptake and cell numbers. The diffusing factor
from fibroblasts appeared to be keratinocyte growth factor (KGF)
since this cytokine increased Type II cell growth in culture and
neutralizing antibody to KGF blocked the observed fibroblast-induced
growth increase. None of the antibodies to various cytokines had any
effect on the ECM induced proliferation. Although the Type II cells
were shown to produce degradative activity for the ECM, there was
little secreted enzyme activity in supernatants and there was no
demonstrated autocrine regulated growth effect. The results suggest
that Type II cell growth may be stimulated by both: a) a matrix bound
factor that acts through a cell contact mediated process; and b) a
fibroblast secreted factor that appears to be KGF.
Received 26 July 1996; accepted in final form 30 October 1996.
APS Manuscript Number L239-6.
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