The angiogenic capacity from ligamentum flavum subsequent to inflammation: A critical component of the pathomechanism of hypertrophy

Hong Joo Moon, Youn Kwan Park, Youngjoon Ryu, Jong Hyun Kim, Taek Hyun Kwon, Hung Seob Chung, Joo Han Kim

    Research output: Contribution to journalArticlepeer-review

    30 Citations (Scopus)


    Study Design.: In vitro study about angiogenic potentiality of ligamentum flavum (LF) cells using coculture of human lumbar LF cells and activated macropage-like THP-1 cells. Objective.: To test our hypothesis that activated LF, which was exposed to inflammation, induces angiogenesis, thus resulting in hypertrophy. Summary of Background Data.: Inflammatory reactions after mechanical stress produce fibrosis and scarring of the LF that result in hypertrophy, a major pathological feature of spinal stenosis. This study evaluated the roles of LF cells in the pathomechanism of hypertrophy, focusing on angiogenesis. Methods.: To determine their response to the inflammatory reaction, human LF cells were cocultured with phorbol myristate acetate-stimulated macrophage-like THP-1 cells. The conditioned media were assayed for tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-β1. Naïve and macrophage-exposed LF cells that responded to TNF-α/IL-1β were compared using the same outcome measures. Hypertrophied LF tissue was stained by TGF-β1 primary antibody using immunohistochemical method. Results.: Larger quantities of IL-6, IL-8, and VEGF were secreted by cocultured cells than by macrophages alone and LF cells alone combined. Prior macrophage exposure increased the secretion of IL-8 and VEGF in response to TNF-α/IL-1β stimulation whereas IL-6 production was increased in response to IL-1β. The coculture appeared to increase TGF-β1 secretion but the level was lower than that for macrophage-like cells alone and LF cells alone combined. Conclusion.: LF cells interact with macrophage-like cells to produce angiogenesis-related factors except TGF-β1. Activated LF cells that have been exposed to macrophage, can impact the inducement of angiogenesis-related factors, suggesting that fibrosis and scarring during inflammatory reaction is the major pathomechanism of LF hypertrophy.

    Original languageEnglish
    Pages (from-to)E147-E155
    Issue number3
    Publication statusPublished - 2012 Feb 1


    • angiogenesis
    • human monocytic THP-1 cell line
    • hypertrophy
    • inflammation
    • ligamentum flavum

    ASJC Scopus subject areas

    • Orthopedics and Sports Medicine
    • Clinical Neurology


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