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Macrophage Polarization and Macrophage-related Factor Expression in Hypertrophy of the Ligamentum Flavum

Overview
Journal Eur Spine J
Specialty Orthopedics
Date 2024 Oct 7
PMID 39375228
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Abstract

Purpose: Owing to the unknow types of infiltrating macrophages and the corresponded factors, we aimed to investigate the specific types of infiltrating macrophages involved in HLF and the expression of macrophage-related factors.

Methods: The ligamentum flavum was obtained from patients with lumbar spinal stenosis (HLF group; n = 15) and lumbar disc herniation (non-hypertrophic ligamentum flavum [NLF] group; n = 15). Ligamentum flavum specimens were paraffin embedded, followed by histological and immunohistochemical staining to identify the macrophage type and expression of macrophage-related factors.

Results: The HLF group demonstrated CD206 marker expression, while the NLF group did not (P < 0.0001; n = 11). CD68 marker was expressed in both groups (P > 0.05; n = 11). CCR7 was not expressed in either group. The expression levels of the extracellular matrix proteins aggrecan (Agg), type I collagen (Coll1), and type II collagen (Coll2) were higher in the HLF group than in the NLF group (P < 0.0001; n = 11). The aging markers p21, p16, and p53 were expressed in the HLF group, but not in the NLF group (P < 0.0001; n = 11). The expression levels of the inflammatory factors TNF-α and IL-1β were higher in the HLF group than in the NLF group (P < 0.0001; n = 11). Similarly, the expression level of the fibrosis factor TGF-β1 was higher in the HLF group than in the NLF group (P < 0.0001; n = 11).

Conclusions: The infiltration of M2 macrophages may be involved in HLF, while involvement of M1 macrophages may only occur early in inflammation. The expression of extracellular matrix proteins and macrophage-related factors was increased. Aging may also be associated with HLF.

References
1.
Hori Y, Suzuki A, Hayashi K, Ohyama S, Yabu A, Maruf M . Long-term, Time-course Evaluation of Ligamentum Flavum Hypertrophy Induced by Mechanical Stress: An Experimental Animal Study. Spine (Phila Pa 1976). 2020; 46(9):E520-E527. DOI: 10.1097/BRS.0000000000003832. View

2.
Yamada T, Horikawa M, Sato T, Kahyo T, Takanashi Y, Ushirozako H . Hypertrophy of the ligamentum flavum in lumbar spinal canal stenosis is associated with abnormal accumulation of specific lipids. Sci Rep. 2021; 11(1):23515. PMC: 8648848. DOI: 10.1038/s41598-021-02818-7. View

3.
Yabe Y, Hagiwara Y, Ando A, Tsuchiya M, Minowa T, Takemura T . Chondrogenic and fibrotic process in the ligamentum flavum of patients with lumbar spinal canal stenosis. Spine (Phila Pa 1976). 2015; 40(7):429-35. DOI: 10.1097/BRS.0000000000000795. View

4.
Ma C, Qi X, Wei Y, Li Z, Zhang H, Li H . Amelioration of ligamentum flavum hypertrophy using umbilical cord mesenchymal stromal cell-derived extracellular vesicles. Bioact Mater. 2022; 19:139-154. PMC: 9014323. DOI: 10.1016/j.bioactmat.2022.03.042. View

5.
Zhong Z, Zha D, Xiao W, Wu S, Wu Q, Zhang Y . Hypertrophy of ligamentum flavum in lumbar spine stenosis associated with the increased expression of connective tissue growth factor. J Orthop Res. 2011; 29(10):1592-7. DOI: 10.1002/jor.21431. View