title: Composition of the extracellular matrix of lymphatic novel threadlike structures: is it keratin?
abstract: Background. The lumen of novel threadlike structures (NTSs) is enclosed by a single layer of endothelial cells surrounded by extracellular matrix (ECM). We hypothesized that collagen may be a component of the ECM associated with lymphatic NTSs. Methods. Six female New Zealand white rabbits were anesthetized, and the NTS structures within lymphatic vessels were identified by contrast-enhanced stereomicroscopy or alcian blue staining. Isolated NTS specimens were stained with acridine orange, YOYO-1, and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI). The structural and molecular composition of the ECM was investigated using transmission electron microscopy (TEM), electrospray ionization-mass spectrometry, and proteomic analysis. Results. The lymph vessel wall was stained red by DiI, and rod-shaped nuclei were stained green by YOYO-1. The area surrounding the NTS was also stained red and contained green rod-shaped nuclei. TEM images showed that the NTS consisted of many ECM fibers and the ECM fibers appeared to be ~100 nm in diameter and had narrowly spaced striated bands. Proteomic analysis of the lymphatic NTS-associated ECM identified 4 proteins: keratin 10, cytokeratin 3, cytokeratin 12, and soluble adenylyl cyclase. Conclusion. The TEM study suggested that the lymphatic NTS-associated ECM did not contain collagen. This was confirmed by proteomic analysis, which showed that keratin was the major component of the ECM.
authors.affiliation: Department of Anesthesiology and Pain Medicine, College of Medicine, Korea University, Seoul 136-705, Republic of Korea.
authors.forename: Hyub
authors.initials: H
authors.lastname: Huh
authors.forename: Byung-Cheon
authors.initials: BC
authors.lastname: Lee
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Ji Woong
authors.initials: JW
authors.lastname: Yoon
authors.forename: Soo Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Cho
authors.forename: Seung Zhoo
authors.initials: SZ
authors.lastname: Yoon