Discontinuous expression of endothelial cell adhesion molecules along initial lymphatic vessels in mesentery: the primary valve structure.
BACKGROUND
Understanding lymphatic fluid uptake requires investigation of the primary valve system located at endothelial cell junctions. The objective of this study was to evaluate the expression pattern of adhesion molecules at endothelial cell junctions in an adult initial lymphatic network.


RESULTS
Mesenteric tissues from adult male Wistar rats were labeled with antibodies against PECAM-1 and VE-cadherin. Endothelial cells along initial lymphatics and blood microvascular networks expressed both junctional molecules. In contrast to continuous junctional labeling along blood vessels, PECAM and VE-cadherin labeling patterns were discontinuous with gaps along lymphatic endothelial cell junctions. Along larger draining vessels in proximal regions of the initial lymphatic network, the majority of labeling gaps along junctions were less than 1microm. In comparison to draining vessels, terminal lymphatics exhibited a decrease in PECAM staining intensity and a decrease in endothelial cell junctional length defined by positive PECAM and VE-cadherin staining.


CONCLUSIONS
These results suggest that primary valves responsible for unidirectional interstitial fluid uptake along initial lymphatic vessels are associated with discontinuous expression of endothelial junction molecules. This feature may render the ability to separate local membrane regions between neighboring endothelial cells.
Murfee
Walter L
WL
Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive, Mail Code 0412, La Jolla, CA 92093, USA. wmurfee@tulane.edu
Rappleye
Jeff W
JW
Ceballos
Mariana
M
Schmid-Schönbein
Geert W
GW
D000818:Animals; D015820:Cadherins / Q000302:isolation & purification / Q000378:metabolism*; D004729:Endothelium, Lymphatic / Q000166:cytology / Q000378:metabolism*; D007365:Intercellular Junctions / Q000378:metabolism*; D008208:Lymphatic System / Q000166:cytology / Q000378:metabolism; D042601:Lymphatic Vessels / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008643:Mesentery; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats
D015820:Cadherins; D019408:Platelet Endothelial Cell Adhesion Molecule-1