title: Immunohistochemical localization of mesenchymal stem cells in ossified human spinal ligaments.
abstract: Mesenchymal stem cells (MSCs) have been isolated from various tissues and used for elucidating the pathogenesis of numerous diseases. In our previous in vitro study, we showed the existence of MSCs in human spinal ligaments and hypothesized that these MSCs contributed to the pathogenesis of ossification of spinal ligaments. The purpose of this study was to use immunohistochemical techniques to analyze the localization of MSCs in ossified human spinal ligaments in situ. Ossified (OLF) or non-ossified ligamentum flavum (non-OLF) samples from the thoracic vertebra were obtained from patients who had undergone posterior spinal surgery. Serial sections were prepared from paraffin-embedded samples, and double immunofluorescence staining was performed using antibodies against markers for MSCs (CD73, CD90 and CD105), endothelial cells (CD31), pericytes (α-smooth muscle actin), and chondrocytes (S100). Immunolocalization of MSCs was observed in the perivascular area and collagenous matrix in spinal ligaments. Markers for MSCs and pericytes were co-expressed in the perivascular area. Compared with non-OLF, OLF had a large amount of neovascularization in the fragmented ligament matrix, and a high accumulation of MSCs around blood vessels. The prevalence of MSCs in OLF within collagenous matrix was significantly higher than that in non-OLF. Chondrocytes near the ossification front in OLF also presented expression of MSC markers. MSCs may contribute to the ectopic ossification process of OLF through endochondral ossification.
authors.affiliation: Department of Pharmacology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan.
authors.forename: Shunfu
authors.initials: S
authors.lastname: Chin
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Furukawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ono
authors.forename: Toru
authors.initials: T
authors.lastname: Asari
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Harada
authors.forename: Kanichiro
authors.initials: K
authors.lastname: Wada
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tanaka
authors.forename: Wataru
authors.initials: W
authors.lastname: Inaba
authors.forename: Hiroki
authors.initials: H
authors.lastname: Mizukami
authors.forename: Shigeru
authors.initials: S
authors.lastname: Motomura
authors.forename: Soroku
authors.initials: S
authors.lastname: Yagihashi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ishibashi
mesh_terms: D003094:Collagen / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008022:Ligaments / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D009999:Ossification, Heterotopic; D013131:Spine / Q000378:metabolism*
chemical_list: D003094:Collagen
keywords: Chondrocytes; Immunohistochemistry; Localization; Mesenchymal stem cells; Neovascularization; Spinal ligament ossification