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Development of the avian lymphatic system
Author(s) -
Wilting Jörg,
Papoutsi Maria,
OthmanHassan Karim,
RodriguezNiedenführ Marc,
Pröls Felicitas,
Tomarev Stanislav I.,
Eichmann Anne
Publication year - 2001
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.1159
Subject(s) - lymphatic system , lymphatic endothelium , biology , lymph , lymphangiogenesis , endothelium , quail , vascular endothelial growth factor c , mesoderm , embryonic stem cell , embryogenesis , pathology , anatomy , microbiology and biotechnology , embryo , immunology , vascular endothelial growth factor a , vascular endothelial growth factor , endocrinology , cancer research , medicine , genetics , vegf receptors , gene , cancer , metastasis
Recently, highly specific markers of the lymphatic endothelium have been found enabling us to reinvestigate the embryonic origin of the lymphatics. Here we present a review of our studies on the development of the lymphatic system in chick and quail embryos. We show that the lymphatic endothelium is derived from two sources: the embryonic lymph sacs and mesenchymal lymphangioblasts. Proliferation studies reveal a BrdU‐labeling index of 11.5% of lymph sac endothelial cells by day 6.25, which drops to 3.5% by day 7. Lymphangioblasts are able to integrate into the lining of lymph sacs. Lymphatic endothelial cells express the vascular endothelial growth factor (VEGF) receptors‐2 and ‐3. Their ligand, VEGF‐C, is expressed almost ubiquitously in embryonic and fetal tissues. Elevated expression levels are found in the tunica media of large blood vessels, which usually serve as major routes for growing lymphatics. The homeobox gene, Prox1 , is expressed in lymphatic but not in blood vascular endothelial cells throughout all stages examined, namely, in developing lymph sacs of day 6 embryos and in lymphatics at day 16. Experimental studies show the existence of lymphangioblasts in the mesoderm, a considerable time before the development of the lymph sacs. Lymphangioblasts migrate from the somites into the somatopleure and contribute to the lymphatics of the limbs. Our studies indicate that these lymphangioblasts already express Prox1 . Microsc. Res. Tech. 55:81–91, 2001. © 2001 Wiley‐Liss, Inc.