Extracellular matrix hyaluronan is a determinant of the endothelial
barrier.
Qiao, Ren-Li, Hwai-Shi Wang, Weihong Yan, Lale E. Odekon, Peter J. Del
Vecchio, Terry J. Smith, and Asrar B. Malik.
Department of Pharmacology, Rush Medical College, Rush-Presbyterian-St.
Luke's Medical Center, Chicago, IL 60612 and Departments of Medicine,
Physiology and Biochemistry and Molecular Biology, The Albany Medical College
and Department of Veterans Affairs Medical Center, Albany, NY 12208
APStracts 2:0064C, 1995.
We measured the hydraulic conductivity (Lp) of the extracellular matrix (ECM)
obtained after detaching bovine pulmonary microvascular endothelial (BPMVEC)
and bovine pulmonary arterial endothelial cell (BPAEC) monolayers from the
ECM at different days postseeding. From day 1 to day 5 in culture, the total
Lp (i.e., of cell monolayer+ECM) decreased from basal values of 17.1+/-4.0 to
8.5+/-1.6 x10-6 cm/s/cmH2O in BPAEC (p<0.05) and 7.6+/-1.1 to 3.7+/-0.8 in
BPMVE (p<0.05), respectively and on day 5 the total Lp values were lower in
BPMVEC than in BPAEC (p<0.05). On the 5th day, ECM Lp was 55.0+/-8.3 in BPAEC
and 10.7+/-0.9 in BPMVEC (p<0.05), indicating that the contribution of ECM to
the total Lp was greater in BPMVEC than in BPAEC. Treatment of [3H]
-acetate-labelled ECM with streptomyces hyaluronidase (HAse; 6 U/ml for 10
min) released 6-fold greater radioactivity in BPMVEC compared to untreated
BPMVEC controls; a similar treatment of BPAEC did not release detectable
radioactivity indicative of a higher hyaluronan content in the BPMVEC ECM.
HAse treatment reduced the differences in total Lp between BPMVEC and BPAEC
at different days postseeding. Moreover, on the 5th day after seeding, the
ECM Lp of BPMVEC increased to a greater extent after HAse treatment than the
ECM of BPAEC. These data indicate that the of hyaluronan component of the ECM
is an important determinant of the endothelial liquid exchange barrier.
Received 22 August 1994; accepted in final form 5 January 1995.
APS Manuscript Number C498-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 27 February 1995.