title: Decreased elastic fibers and increased proteoglycans in the ligamentum flavum of patients with lumbar spinal canal stenosis.
abstract: Elastic fibers and proteoglycans are major components of the extracellular matrix and their changes have been reported in some pathological conditions. Further, recent studies have indicated that some glycosaminoglycans and proteoglycans inhibit elastic fiber assembly. The purpose of this study was to investigate changes of the elastic fibers and proteoglycans in the ligamentum flavum and analyze their relationships to thickening of the ligamentum flavum from lumbar spinal canal stenosis (LSCS). Ligamentum flavum samples were collected from 20 patients with LSCS (thickened flavum group) and 10 patients with lumbar disc herniation (non-thickened flavum group) as a control. Elastica-Masson staining and alcian blue staining were used to compare the relationship between the changes in the elastic fibers and proteoglycans. Gene and protein expressions of the elastic fibers and proteoglycans were analyzed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. Histological changes indicated that proteoglycans mainly increased on the dorsal side of the ligamentum flavum in accordance with the decreased elastic fibers in the thickened flavum group. The gene and protein expressions of fibrillin-2 and DANCE were significantly lower and decorin, lumican, osteoglycin, and versican were significantly higher in the thickened flavum group. Our study shows that elastic fibers decrease and proteoglycans increase in the thickened ligamentum flavum. Decreased gene expression of elastogenesis and disrupted elastic fiber assembly caused by increased proteoglycans may lead to a loss of elasticity in the thickened ligamentum flavum. Decreased elasticity may cause buckling of the tissue, which leads to thickening of the ligamentum flavum. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1241-1247, 2016.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yabe
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hagiwara
authors.affiliation: Tohoku Fukushi University, Sendai, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tsuchiya
authors.affiliation: Department of Otrhopaedic Surgery, Takeda General Hospital, Aizuwakamatsu, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Honda
authors.affiliation: Division of Advanced Prosthetic Dentistry, Graduate School of Dentistry, Tohoku University, Sendai, Japan.
authors.forename: Kouki
authors.initials: K
authors.lastname: Hatori
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Sonofuchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kanazawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Koide
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Sekiguchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Itaya
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004547:Elastic Tissue / Q000378:metabolism*; D005260:Female; D006801:Humans; D017843:Ligamentum Flavum / Q000378:metabolism* / Q000473:pathology; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D011509:Proteoglycans / Q000378:metabolism*; D013130:Spinal Stenosis / Q000209:etiology / Q000378:metabolism*
chemical_list: D011509:Proteoglycans
keywords: elastogenesis; ligamentum flavum; lumbar spinal canal stenosis; proteoglycans; thickening