The measurement of blood-tissue permeability in the lung has proven to be extremely difficult. We have developed a new in vitro method to measure the permeability of cultured endothelial cell layers from pulmonary arteries, veins, and microvessels. The method offers a fresh approach and overcomes many of the difficulties of whole animal methods used to study the increased permeability edema often characteristic of the adult respiratory distress syndrome. Blood-tissue permeability increases are difficult to prove in animal models of increased permeability edema. For example, investigators have such the sheep lung- lymph preparation and stimuli such as histamine, endotoxin, and thrombin as models of lung injury similar to increased permeability edema. However, blood-tissue permeability changes cannot be clearly identified in these animal models, since the lung injury is accompanied by increased intravascular pressures which could also account for the observed increased flux of fluid and solutes. In vitro methods will help identify specific permeability changes induced by agents producing lung injury in animals. Using recent advances in cell culture methods, the permeability characteristics of the endothelial component of the blood-tissue barrier have begun to be investigated. However, these results are being questioned, since these in vitro methods find permeabilities 1000 times greater than in vivo estimates. In preliminary experiments, our in vitro method finds endothelial permeabilities similar to in vivo estimates. This new method utilizes a monolayer of endothelial cells cultured on microcarrier beads as a selective barrier to control the passage of molecular species from the mobile phase of a liquid chromatography column to the stationary phase within the cell covered microcarrier beads. We propose to use this method to clarify the role of the endothelial barrier in blood-tissue permeability and, in addition, measure how the permeability properties are altered by naturally occurring stimuli, i.e. autacoids. This proposal has three main aims: 1) to measure the in vitro intercellular permeability of the pulmonary endothelial cell layer to mannitol and polyethylene glycol; 2) to characterize the permeability of the pulmonary endothelial cell layer with respect to tracer size and charge; and 3) to test the hypothesis that autacoids alter pulmonary endothelial cell permeability by measuring permeability changes produced by three autacoids, which have been described as reversible modulators of blood-tissue permeability in the lung: norepinephrine, thrombin and histamine.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
7R01HL040554-02
Application #
3357791
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1989-07-10
Project End
1993-06-30
Budget Start
1989-07-10
Budget End
1990-06-30
Support Year
2
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37203
Alexander, J S; Patton, W F; Christman, B W et al. (1998) Platelet-derived lysophosphatidic acid decreases endothelial permeability in vitro. Am J Physiol 274:H115-22
Haselton, F R; Heimark, R L (1997) Role of cadherins 5 and 13 in the aortic endothelial barrier. J Cell Physiol 171:243-51
Haselton, F R; Woodall, J H; Alexander, J S (1996) Neutrophil-endothelial interactions in a cell-column model of the microvasculature: effects of fMLP. Microcirculation 3:329-42
Harris, T R; Waters, C M; Haselton, F R (1994) Use of scaling theory to relate measurements of lung endothelial barrier permeability. J Appl Physiol 77:2496-505
Waters, C M; Alexander, J S; Harris, T R et al. (1993) Perilla ketone increases endothelial cell monolayer permeability in vitro. J Appl Physiol 74:2493-501
Haselton, F R; Alexander, J S; Mueller, S N (1993) Adenosine decreases permeability of in vitro endothelial monolayers. J Appl Physiol 74:1581-90
Alexander, J S; Blaschuk, O W; Haselton, F R (1993) An N-cadherin-like protein contributes to solute barrier maintenance in cultured endothelium. J Cell Physiol 156:610-8
Haselton, F R; Alexander, J S (1992) Platelets and a platelet-released factor enhance endothelial barrier. Am J Physiol 263:L670-8
Howell, R E; Haselton, F R; Mueller, S N (1990) Angiotensin-converting enzyme kinetics in an endothelial cell column. Am J Physiol 258:L188-94
Haselton, F R; Mueller, S N; Howell, R E et al. (1989) Chromatographic demonstration of reversible changes in endothelial permeability. J Appl Physiol 67:2032-48