title: Lymphangiogenesis following obstruction of large postnodal lymphatics in sheep.
abstract: We examined the impact of lymph flow obstruction in large post-nodal lymphatic vessels in sheep. A silk ligature was placed 2 cm downstream from the prescapular or popliteal lymph node and tightened to interrupt flow. At 6, 12 and 16 weeks after lymph flow blockage, a network of small interconnecting lymphatics (approximately 10-40 microm in diameter) could be observed in the vicinity of the ligature. These were identified using antibodies to the lymphatic endothelial markers LYVE-1 or VEGFR-3 or unequivocally, with the upstream intraluminal injection of the non-specific cell dye CFDA-SE. The observed lymphangiogenesis coincided with increased levels of Prox1, Tie2 (Y992) phosphorylation, MAPK activation, and decreased Akt activition. In the popliteal preparations, saline was infused into the prenodal ducts upstream of the regeneration site. The slopes of the inflow pressure versus flow relationships were 17.3+/-3.6, immediately after vessel obstruction, 36.2+/-9.6 at 6 weeks and 15.0+/-5.3 at 12-16 weeks. For comparison, the average slope in a completely intact popliteal system was 3.1+/-0.3 (from a previous publication). The resistance to flow remained high up to 12-16 weeks after flow obstruction suggesting that normal flow parameters had not been achieved over this time. The lymph node appeared to have some role in limiting the impact of post-nodal lymph obstruction, a function that appeared to be compromised by lymph stasis.
authors.affiliation: Neuroscience Research Program, Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario, Canada M4N 3M5.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Jila
authors.forename: Harold
authors.initials: H
authors.lastname: Kim
authors.forename: Vicky P K H
authors.initials: VP
authors.lastname: Nguyen
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Dumont
authors.forename: John
authors.initials: J
authors.lastname: Semple
authors.forename: Dianna
authors.initials: D
authors.lastname: Armstrong
authors.forename: Eva
authors.initials: E
authors.lastname: Seto
authors.forename: Miles
authors.initials: M
authors.lastname: Johnston
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005452:Fluoresceins; D005456:Fluorescent Dyes; D018398:Homeodomain Proteins / Q000378:metabolism; D018960:Hyaluronan Receptors / Q000378:metabolism; D007150:Immunohistochemistry; D008026:Ligation; D008196:Lymph / Q000378:metabolism*; D008198:Lymph Nodes / Q000378:metabolism / Q000503:physiopathology; D042583:Lymphangiogenesis; D008206:Lymphatic Diseases / Q000378:metabolism / Q000503:physiopathology*; D042601:Lymphatic Vessels / Q000378:metabolism / Q000503:physiopathology* / Q000601:surgery; D018613:Microscopy, Confocal; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D051058:Oncogene Protein v-akt / Q000378:metabolism; D011312:Pressure; D042787:Receptor, TIE-2 / Q000378:metabolism; D012038:Regeneration; D012756:Sheep; D015398:Signal Transduction; D013388:Succinimides; D013997:Time Factors; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000378:metabolism; D000098551:Prospero-Related Homeobox 1 Protein
chemical_list: C087165:5-(6)-carboxyfluorescein diacetate succinimidyl ester; D005452:Fluoresceins; D005456:Fluorescent Dyes; D018398:Homeodomain Proteins; D018960:Hyaluronan Receptors; D013388:Succinimides; D025521:Tumor Suppressor Proteins; D000098551:Prospero-Related Homeobox 1 Protein; D042787:Receptor, TIE-2; D040321:Vascular Endothelial Growth Factor Receptor-3; D051058:Oncogene Protein v-akt; D020928:Mitogen-Activated Protein Kinases