Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Dec;13(6):53.
doi: 10.3892/br.2020.1360. Epub 2020 Sep 29.

Role of skeletal macrophages in fracture repair: A systematic review

Zihao Wan  1   2 , Lih-Ying Shin  1 , Yu-Fan Wang  1 , Zhihao Huang  3 , Yanjing Dong  2 , Chien-Wei Lee  4 , Shekhar-Madhukar Kumta  1 , Oscar Kuang-Sheng Lee  1   4   5
Affiliations

Role of skeletal macrophages in fracture repair: A systematic review

Zihao Wan et al. Biomed Rep. 2020 Dec.

Abstract

In the field of bone research, the importance of the function of skeletal macrophages (sMΦ) and their crucial role in immune homeostasis and bone regeneration has been extensively studied. The aim of the present systematic review was to summarize the role of sMΦ in bone fracture healing and to evaluate their potential for immunoregulatory therapy in bone regeneration. A systematic literature search of PubMed and Embase® was performed to retrieve studies on the role of sMΦ in bone injury repair. The Systematic Review Centre for Laboratory animal Experimentation tool was used to assess the risk of bias of the studies included. A total of four articles were included in the present review. A relatively high risk of bias was identified in the included articles as none of the assessors in these studies were blinded. sMΦ were defined by the surface markers F4/80+, Mac-2- / low, TRAP-, CD169+, Ly6G- and CD115low. All of the studies provided support for the essential role of sMΦ in intramembranous ossification or endochondral ossification during fracture healing. F4/80+Mac-2-CD169+ sMΦ are a promising therapeutic target for immunoregulatory therapy of bone repair due to their essential role in bone formation and homeostasis. Future studies aimed at profiling and modulating sMΦ to promote bone regeneration are required.

Keywords: bone fracture; immune reaction; inflammation; skeletal macrophage.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Flowchart of the study selection process.
Figure 2
Figure 2
Risk of bias assessment. The Systematic Review Centre for Laboratory animal Experimentation was used to assess the risk of bias in the included studies. Green, low risk of bias; red, high risk of bias; yellow, unclear risk of bias.
Figure 3
Figure 3
Participation of sMΦs in fracture repair. Lower panel: sMΦs located at the border of cortical bone form a sMΦ lining. During the anabolic phase, woven bone bridges the injury sites, and the bone fracture heals via endochondral ossification and intramembranous ossification. Inset: Immune cells and MSCs are recruited to the fracture site. sMΦs form a canopy-like structure over the cuboidal-shaped osteoblasts. MΦ, macrophage; sMΦ, skeletal MΦ; MSC, mesenchymal stem cell; HSC, hematopoietic stem cell; PMN, polymorphonuclear leucocyte.
See this image and copyright information in PMC

References

    1. Chen W, Lv H, Liu S, Liu B, Zhu Y, Chen X, Yang G, Liu L, Zhang T, Wang H, et al. National incidence of traumatic fractures in China: A retrospective survey of 512 187 individuals. Lancet Glob Heal. 2017;5:e807–e817. doi: 10.1016/S2214-109X(17)30222-X. - DOI - PubMed
    1. Schneider E, Goldhahn J, Burckhardt P. The challenge: Fracture treatment in osteoporotic bone. Osteoporos Int. 2005;16:1–2. doi: 10.1007/s00198-004-1766-3. - DOI - PubMed
    1. Holmes D. Non-union bone fracture: A quicker fix. Nature. 2017;550(S193) doi: 10.1038/550S193a. - DOI - PubMed
    1. Loi F, Córdova LA, Pajarinen J, Lin TH, Yao Z, Goodman SB. Inflammation, fracture and bone repair. Bone. 2016;86:119–130. doi: 10.1016/j.bone.2016.02.020. - DOI - PMC - PubMed
    1. Marsell R, Einhorn TA. The biology of fracture healing. Injury. 2011;42:551–555. doi: 10.1016/j.injury.2011.03.031. - DOI - PMC - PubMed

LinkOut - more resources