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NEM and filipin increase albumin transport in lung microvessels

Rippe, Bengt LU and Taylor, Aubrey (2001) In American Journal of Physiology 280(1). p.34-41
Abstract
This study was undertaken to evaluate the role of transcytosis as a bulk transfer mechanism for the passage of albumin from blood to tissue. Isolated rat lungs were continuously weighed and perfused with an albumin-serum buffer solution under strictly controlled hemodynamic conditions, which allowed measurements of microvascular pressure and of the capillary filtration coefficient (LpS). With the use of a tissue uptake technique, it was possible to determine lung albumin clearance under isogravimetric conditions (Cliso), or at elevated filtration rates, to obtain an "apparent albumin reflection coefficient" (sigma alb). Experiments were performed during control and after reducing lung temperature from 35° to 22°C and after infusions of the... (More)
This study was undertaken to evaluate the role of transcytosis as a bulk transfer mechanism for the passage of albumin from blood to tissue. Isolated rat lungs were continuously weighed and perfused with an albumin-serum buffer solution under strictly controlled hemodynamic conditions, which allowed measurements of microvascular pressure and of the capillary filtration coefficient (LpS). With the use of a tissue uptake technique, it was possible to determine lung albumin clearance under isogravimetric conditions (Cliso), or at elevated filtration rates, to obtain an "apparent albumin reflection coefficient" (sigma alb). Experiments were performed during control and after reducing lung temperature from 35° to 22°C and after infusions of the transcytosis inhibitors N-ethylmaleimide (NEM) or filipin. Cooling moderately increased vascular resistance and reduced LpS and Cliso largely in proportion to the induced increases in viscosity. At 35°C, NEM (0.13 mM) caused a marked increase in Lp5 and in Cl150 and also caused a reduction in sigma alb. Furthermore, Cliso increased for the highest dose of filipin tested (1.8 µg/ml). The demonstrated relative cooling insensitivity of the transfer of albumin across the endothelium in rat lungs does not support the contention of transcytosis of proteins across the endothelium. Furthermore, neither NEM nor filipin inhibited lung microvascular albumin transport, but actually increased lung endothelial permeability. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
American Journal of Physiology
volume
280
issue
1
pages
34 - 41
publisher
American Pysiological Society
external identifiers
  • scopus:0035007306
ISSN
0002-9513
language
English
LU publication?
yes
id
70b42a0f-f68a-42be-b0a1-1f49fd276935 (old id 1260180)
alternative location
http://ajpheart.physiology.org/cgi/content/abstract/280/1/H34
date added to LUP
2008-10-28 15:36:56
date last changed
2017-04-16 04:30:02
@article{70b42a0f-f68a-42be-b0a1-1f49fd276935,
  abstract     = {This study was undertaken to evaluate the role of transcytosis as a bulk transfer mechanism for the passage of albumin from blood to tissue. Isolated rat lungs were continuously weighed and perfused with an albumin-serum buffer solution under strictly controlled hemodynamic conditions, which allowed measurements of microvascular pressure and of the capillary filtration coefficient (LpS). With the use of a tissue uptake technique, it was possible to determine lung albumin clearance under isogravimetric conditions (Cliso), or at elevated filtration rates, to obtain an "apparent albumin reflection coefficient" (sigma alb). Experiments were performed during control and after reducing lung temperature from 35° to 22°C and after infusions of the transcytosis inhibitors N-ethylmaleimide (NEM) or filipin. Cooling moderately increased vascular resistance and reduced LpS and Cliso largely in proportion to the induced increases in viscosity. At 35°C, NEM (0.13 mM) caused a marked increase in Lp5 and in Cl150 and also caused a reduction in sigma alb. Furthermore, Cliso increased for the highest dose of filipin tested (1.8 µg/ml). The demonstrated relative cooling insensitivity of the transfer of albumin across the endothelium in rat lungs does not support the contention of transcytosis of proteins across the endothelium. Furthermore, neither NEM nor filipin inhibited lung microvascular albumin transport, but actually increased lung endothelial permeability.},
  author       = {Rippe, Bengt and Taylor, Aubrey},
  issn         = {0002-9513},
  language     = {eng},
  number       = {1},
  pages        = {34--41},
  publisher    = {American Pysiological Society},
  series       = {American Journal of Physiology},
  title        = {NEM and filipin increase albumin transport in lung microvessels},
  volume       = {280},
  year         = {2001},
}