Pulmonary interstitial pressure and proteoglycans during
development of pulmonary edema.
Negrini, Daniela, Alberto Passi, Giancarlo De Luca, and Giuseppe
Miserocchi.
Istituto di Fisiologia Umana, Facolt[grave]a di Medicina e
Chirurgia, Universit[grave]a degli Studi, Milano, Dipartimento di
Biochimica, Facolt[grave]a di Medicina e Chirurgia II,
Universit[grave]a di Pavia, Italy
APStracts 2:0526H, 1995.
In anesthetized adult rabbits pulmonary perivascular interstitial
pressure (Pip) measured by micropuncture technique with intact
pleural space, averaged -10.5 +/- 1.9 (1 SD) cmH2O in control
conditions, with a lung wet weight to dry weight ratio (W/D) of 4.8
+/- 0.2. Saline infusion (120 ml i.v. over 120 min) induced
interstitial edema, increasing Pip to 3.62 +/-1.6 cmH2O with no
significant increase in W/D ratio (5.13 +/- 0.1). For i.v. saline
infusion exceeding 140 ml, Pip decreased to about atmospheric
pressure with development of severe edema that was characterized by
an increase of W/D ratio (> 7) with no further change in Pip. In
a separate set of animals, pulmonary interstitial proteoglycans (PGs)
were investigated after sequential extraction of the tissue with 0.4
M and 4 M guanidil chloride (GuHCl) under control conditions and with
interstitial (100 ml saline load in 100 min) and severe edema (>
200 ml total infusion). The extractability of PGs increased
constantly with increasing lung W/D ratio. PG content in total
extracts was evaluated by determination of hexuronate content which
was 195.4 +/- 1.5 [mu]g/g dry tissue in control lungs, 217.9 +/- 1.6
in interstitial edema and 316.4 +/- 2.7 in severe edema. Moreover,
edema development was coupled with an increase in efficiency of PG
extraction with 0.4 M GuHCl. These findings suggested a weakening of
PG interactions with other components of the extracellular matrix.
Electrophoretic and gel-filtration analysis showed that the relative
content of PG populations with high molecular size decreased
constantly in 0.4 M GuHCl extract with increasing water loading. We
propose to relate the inflection of Pip in the transition from
interstitial to severe edema to PGs breakdown which might greatly
affect ECM structural organization, including collagen spreading
and/or rupture of epithelial layer.
Received 14 September 1995; accepted in final form 9 November
1995.
APS Manuscript Number H866-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95