%0 Journal Article
%T Proliferating mesodermal cells in murine embryos exhibiting macrophage and lymphendothelial characteristics
%A Kerstin Buttler
%A Taichi Ezaki
%A J£¿rg Wilting
%J BMC Developmental Biology
%D 2008
%I BioMed Central
%R 10.1186/1471-213x-8-43
%X We observed cells co-expressing both types of markers (e.g. Prox1 ¨C Lyve-1 ¨C F4/80 triple-positive) located in the mesoderm, immediately adjacent to, and within lymph vessels. Our proliferation studies with Ki-67 antibodies showed high proliferative capacities of both the Lyve-1-positive LECs of lymph sacs/lymphatic sprouts and the Lyve-1-positive mesenchymal cells.Our data argue for a dual origin of LECs in the mouse, although the primary source of embryonic LECs may reside in specific embryonic veins and mesenchymal lymphangioblasts integrated secondarily into lymph vessels. The impact of a dual source of LECs for ontogenetic, phylogenetic and pathological lymphangiogenesis is discussed.The important physiological and pathophysiological roles of the lymphatic vascular system for fluid homeostasis, immune surveillance, inflammation and tumour metastasis justify intensive studies of this hardly visible portion of the vascular system [1,2]. Insufficient development of lymph vessels becomes immediately apparent as lymph oedema, which mostly affects the legs and the genital region of patients. Primary lymph oedema (Nonne-Milroy Syndrome) is caused by mutations in the tyrosine kinase domain of the Vascular Endothelial Growth Factor Receptor-3 (VEGFR-3) gene on 5q35.3 [3,4]. Kaposi's sarcoma probably represents a form of lymphatic endothelial cell (LEC) hyperplasia [5], but circulating precursor cells may also be involved [6]. However, it is still not clear whether lymphangioma, which is found in 1.2 ¨C 2.8¡ë of infants [7], is due to hyperplasia of LECs or structural malformations of lymph vessels [8]. These uncertainties with respect to the pathobiology of lymph vessels are based on the fact that the mechanisms of normal embryonic lymphangiogenesis and the origin of LECs are not sufficiently well understood.Following the identification of specific markers for LECs, our knowledge of the structure and function of lymph vessels and the molecular equipment of LECs has increa
%U http://www.biomedcentral.com/1471-213X/8/43