Systemic Administration of Recombinant Irisin Accelerates Fracture Healing in Mice

To date, pharmacological strategies designed to accelerate bone fracture healing are lacking. We subjected 8-week-old C57BL/6 male mice to closed, transverse, mid-diaphyseal tibial fractures and treated them with intraperitoneal injection of a vehicle or r-irisin (100 µg/kg/weekly) immediately following fracture for 10 days or 28 days. Histological analysis of the cartilaginous callus at 10 days showed a threefold increase in Collagen Type X (p = 0.0012) and a reduced content of proteoglycans (40%; p = 0.0018). Osteoclast count within the callus showed a 2.4-fold increase compared with untreated mice (p = 0.026), indicating a more advanced stage of endochondral ossification of the callus during the early stage of fracture repair. Further evidence that irisin induced the transition of cartilage callus into bony callus was provided by a twofold reduction in the expression of SOX9 (p = 0.0058) and a 2.2-fold increase in RUNX2 (p = 0.0137). Twenty-eight days post-fracture, microCT analyses showed that total callus volume and bone volume were increased by 68% (p = 0.0003) and 67% (p = 0.0093), respectively, and bone mineral content was 74% higher (p = 0.0012) in irisin-treated mice than in controls. Our findings suggest that irisin promotes bone formation in the bony callus and accelerates the fracture repair process, suggesting a possible use as a novel pharmacologic modulator of fracture healing.

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Endogenous Production of n-3 Polyunsaturated Fatty Acids Promotes Fracture Healing in Mice

Journal of Healthcare Engineering ◽

10.1155/2017/3571267 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Yuhui Chen ◽

He Cao ◽

Dawei Sun ◽

Changxin Lin ◽

Liang Wang ◽

...

Keyword(s):

Transgenic Mice ◽

Fracture Healing ◽

Histological Analysis ◽

Callus Formation ◽

Healing Process ◽

Proximal Femoral Fracture ◽

Fracture Repair ◽

Micro Ct ◽

Micro Computed Tomography ◽

X Ray

Bone fracture is a global healthcare issue for high rates of delayed healing and nonunions. Although n-3 polyunsaturated fatty acid (PUFA) is considered as a beneficial factor for bone metabolism, only few studies till date focused on the effects of n-3 PUFAs on fracture healing. In this study, we investigated the effect of endogenous n-3 PUFAs on fracture healing by measuring femur fracture repair in bothfat-1transgenic mice and WT mice. Proximal femoral fracture model was established infat-1transgenic mice and WT mice, respectively, and then the fracture was analyzed by using X-ray, micro-computed tomography (micro-CT), and histological assessment at 7, 14, 21, 28, and 35 days after fixation. The results showed that compared with WT mice,fat-1mice exhibited acceleration in fracture healing through radiographic and histological analysis (18–21 days versus 21–28 days postfracture). Meanwhile, X-ray and micro-CT analysis that showed better remodeling callus formation were in thefat-1group compared to WT group. Furthermore, histological analysis revealed that endogenous n-3 PUFAs promoted local endochondral ossification and accelerated the remodeling of calcified calluses after fracture. In conclusion, the present study indicated that endogenously produced n-3 PUFAs promote fracture healing process and accelerate bone remodeling in mice, and supplementation of n-3 PUFAs was positively associated with fracture healing.

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Role of Dynamic Loading on Early Stage of Bone Fracture Healing

Annals of Biomedical Engineering ◽

10.1007/s10439-018-2083-x ◽

2018 ◽

Vol 46 (11) ◽

pp. 1768-1784 ◽

Cited By ~ 13

Author(s):

Smriti Ghimire ◽

Saeed Miramini ◽

Martin Richardson ◽

Priyan Mendis ◽

Lihai Zhang

Keyword(s):

Fracture Healing ◽

Dynamic Loading ◽

Bone Fracture ◽

Early Stage ◽

Bone Fracture Healing

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Systemic Mesenchymal Stem Cell Delivery and Axial Mechanical Stimulation Accelerate Fracture Healing

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192554 ◽

2008 ◽

Author(s):

Aaron S. Weaver ◽

Yu-Ping Su ◽

Dana L. Begun ◽

Ralph T. Zade ◽

Andrea I. Alford ◽

...

Keyword(s):

Fracture Healing ◽

Bone Repair ◽

Local Environment ◽

Cell Types ◽

Repair Process ◽

Fracture Site ◽

Fracture Repair ◽

Stem Cell Delivery ◽

Numerous Cell ◽

Local Cell

Fracture healing is a complex process involving numerous cell types, whose actions are regulated by many factors in their local environment. Mechanical factors are known to exert a strong influence on the actions of these cells and the progression of the repair process. While prior studies have investigated the effect of physical forces on cell differentiation, biofactor expression, and mechanical competence of repair, the mechanosensory and response mechanisms are poorly understood. This study was designed to explore the influence of a controlled mechanical environment on temporal aspects of the bone repair process. Specifically, this study examines how the timing of an applied strain influences local cell behavior during fracture repair, and how this load affects the migration of systemically introduced mesenchymal stem cells (MSCs) to the fracture site.

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PREDICTION OF THE TREND OF BONE FRACTURE HEALING BASED ON THE RESULTS OF THE EARLY STAGES SIMULATIONS: A FINITE ELEMENT STUDY

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519419500210 ◽

2019 ◽

Vol 19 (05) ◽

pp. 1950021

Author(s):

JALIL NOURISA ◽

GHOLAMREZA ROUHI

Keyword(s):

Finite Element ◽

Fracture Healing ◽

Bone Fracture ◽

Mechanical Stability ◽

Early Stage ◽

Healing Process ◽

Fibrous Tissue ◽

Fe Model ◽

Bone Fracture Healing ◽

Early Stages

To date, several studies have implied the importance of early stage mechanical stability in the bone fracture healing process. This study aimed at finding a correlation between the predicted different tissue phenotypes in the early stages of healing and the ultimate healing outcome. For this purpose, the process of fracture healing was numerically simulated employing an axisymmetric bi-phasic finite element (FE) model for three initial gap sizes of 1, 3 and 6[Formula: see text]mm and four initial interfragmentary strains (IFS) of 7%, 11%, 15% and 19%. The model was validated with experimental and other numerical studies from the literature. Results of this study showed that the amount of cartilage and fibrous tissue observed in the early stage after fracture can be used to qualitatively assess the outcome of complete bone healing process. Greater amount of cartilage in early stage of healing process yielded faster callus maturation, and delayed maturation of callus was predicted in the case of high fibrous tissue production. Results of this study can be used to provide an estimation of the performance of different fixation systems by considering the amounts of cartilage and fibrous tissues observed in the early stage of healing.

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Exogenous PTH 1-34 Attenuates Impaired Fracture Healing in Endogenous PTH Deficiency Mice via Activating Indian Hedgehog Signaling Pathway and Accelerating Endochondral Ossification

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.750878 ◽

2022 ◽

Vol 9 ◽

Author(s):

Cheng Ma ◽

Huan Liu ◽

Yifan Wei ◽

He Li ◽

Dengshun Miao ◽

...

Keyword(s):

Fracture Healing ◽

Signaling Pathway ◽

Endochondral Ossification ◽

Healing Process ◽

Fracture Repair ◽

Luciferase Reporter ◽

Endochondral Bone Formation ◽

Fracture Callus ◽

Endochondral Bone ◽

Bony Callus

Fracture healing is a complicated, long-term, and multistage repair process. Intermittent administration of parathyroid hormone (PTH) has been proven effective on intramembranous and endochondral bone formation during the fracture healing process, however, the mechanism is unclear. In this study, we investigated the role of exogenous PTH and endogenous PTH deficiency in bone fracture healing and explored the mechanism by using PTH knockout (PTH-/-) mice and ATDC5 cells. In a mouse femur fracture model, endogenous PTH deficiency could delay endochondral ossification whereas exogenous PTH promotes accumulation of endochondral bone, accelerates cartilaginous callus conversion to bony callus, enhances maturity of bony callus, and attenuates impaired fracture healing resulting from endogenous PTH deficiency. In fracture callus tissue, endogenous PTH deficiency could inhibit chondrocyte proliferation and differentiation whereas exogenous PTH could activate the IHH signaling pathway to accelerate endochondral ossification and rescue impaired fracture healing resulting from endogenous PTH deficiency. In vitro, exogenous PTH promotes cell proliferation by activating IHH signaling pathway on ATDC5 cells. In mechanistic studies, by using ChIP and luciferase reporter assays, we showed that PTH could phosphorylate CREB, and subsequently bind to the promoter of IHH, causing the activation of IHH gene expression. Therefore, results from this study support the concept that exogenous PTH 1-34 attenuates impaired fracture healing in endogenous PTH deficiency mice via activating the IHH pathway and accelerating endochondral ossification. Hence, the investigation of the mechanism underlying the effects of PTH treatment on fracture repair might guide the exploration of effective therapeutic targets for fracture.

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Interactions between MSCs and Immune Cells: Implications for Bone Healing

Journal of Immunology Research ◽

10.1155/2015/752510 ◽

2015 ◽

Vol 2015 ◽

pp. 1-17 ◽

Cited By ~ 53

Author(s):

Tracy K. Kovach ◽

Abhijit S. Dighe ◽

Peter I. Lobo ◽

Quanjun Cui

Keyword(s):

Fracture Healing ◽

Bone Healing ◽

Immune Cells ◽

Bone Repair ◽

Repair Process ◽

The United States ◽

Fracture Repair ◽

Cell Based Therapy

It is estimated that, of the 7.9 million fractures sustained in the United States each year, 5% to 20% result in delayed or impaired healing requiring therapeutic intervention. Following fracture injury, there is an initial inflammatory response that plays a crucial role in bone healing; however, prolonged inflammation is inhibitory for fracture repair. The precise spatial and temporal impact of immune cells and their cytokines on fracture healing remains obscure. Some cytokines are reported to be proosteogenic while others inhibit bone healing. Cell-based therapy utilizing mesenchymal stromal cells (MSCs) is an attractive option for augmenting the fracture repair process. Osteoprogenitor MSCs not only differentiate into bone, but they also exert modulatory effects on immune cells via a variety of mechanisms. In this paper, we review the current literature on bothin vitroandin vivostudies on the role of the immune system in fracture repair, the use of MSCs in the enhancement of fracture healing, and interactions between MSCs and immune cells. Insight into this paradigm can provide valuable clues in identifying cellular and noncellular targets that can potentially be modulated to enhance both natural bone healing and bone repair augmented by the exogenous addition of MSCs.

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Akkermansia muciniphila promotes type H vessel formation and bone fracture healing by reducing gut permeability and inflammation

Disease Models & Mechanisms ◽

10.1242/dmm.043620 ◽

2020 ◽

Vol 13 (11) ◽

pp. dmm043620 ◽

Cited By ~ 1

Author(s):

Jiang-Hua Liu ◽

Tao Yue ◽

Zhong-Wei Luo ◽

Jia Cao ◽

Zi-Qi Yan ◽

...

Keyword(s):

Fracture Healing ◽

Systemic Inflammation ◽

Bone Healing ◽

Bone Fracture ◽

Early Stage ◽

Gut Permeability ◽

Bone Fracture Healing ◽

Gut Barrier ◽

Vessel Formation ◽

Akkermansia Muciniphila

ABSTRACTImproving revascularization is one of the major measures in fracture treatment. Moderate local inflammation triggers angiogenesis, whereas systemic inflammation hampers angiogenesis. Previous studies showed that Akkermansia muciniphila, a gut probiotic, ameliorates systemic inflammation by tightening the intestinal barrier. In this study, fractured mice intragastrically administrated with A. muciniphila were found to display better fracture healing than mice treated with vehicle. Notably, more preosteclasts positive for platelet-derived growth factor-BB (PDGF-BB) were induced by A. muciniphila at 2 weeks post fracture, coinciding with increased formation of type H vessels, a specific vessel subtype that couples angiogenesis and osteogenesis, and can be stimulated by PDGF-BB. Moreover, A. muciniphila treatment significantly reduced gut permeability and inflammation at the early stage. Dextran sulfate sodium (DSS) was used to disrupt the gut barrier to determine its role in fracture healing and whether A. muciniphila still can stimulate bone fracture healing. As expected, A. muciniphila evidently improved gut barrier, reduced inflammation and restored the impaired bone healing and angiogenesis in DSS-treated mice. Our results suggest that A. muciniphila reduces intestinal permeability and alleviates inflammation, which probably induces more PDGF-BB+ preosteoclasts and type H vessel formation in callus, thereby promoting fracture healing. This study provides the evidence for the involvement of type H vessels in fracture healing and suggests the potential of A. muciniphila as a promising strategy for bone healing.This article has an associated First Person interview with the first author of the paper.

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Histone demethylase LSD1 is critical for endochondral ossification during bone fracture healing

Science Advances ◽

10.1126/sciadv.aaz1410 ◽

2020 ◽

Vol 6 (45) ◽

pp. eaaz1410

Author(s):

Jun Sun ◽

Heng Feng ◽

Wenhui Xing ◽

Yujiao Han ◽

Jinlong Suo ◽

...

Keyword(s):

Retinoic Acid ◽

Fracture Healing ◽

Bone Regeneration ◽

Bone Fracture ◽

Endochondral Ossification ◽

Callus Formation ◽

Critical Factor ◽

Fracture Repair ◽

Retinoic Acid Signaling ◽

Bone Fracture Healing

Bone fracture is repaired predominantly through endochondral ossification. However, the regulation of endochondral ossification by key factors during fracture healing remains largely enigmatic. Here, we identify histone modification enzyme LSD1 as a critical factor regulating endochondral ossification during bone regeneration. Loss of LSD1 in Prx1 lineage cells severely impaired bone fracture healing. Mechanistically, LSD1 tightly controls retinoic acid signaling through regulation of Aldh1a2 expression level. The increased retinoic acid signaling in LSD1-deficient mice suppressed SOX9 expression and impeded the cartilaginous callus formation during fracture repair. The discovery that LSD1 can regulate endochondral ossification during fracture healing will benefit the understanding of bone regeneration and have implications for regenerative medicine.

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PHOSPHO1 is essential for normal bone fracture healing

Bone and Joint Research ◽

10.1302/2046-3758.76.bjr-2017-0140.r2 ◽

2018 ◽

Vol 7 (6) ◽

pp. 397-405 ◽

Cited By ~ 7

Author(s):

M. W. Morcos ◽

H. Al-Jallad ◽

J. Li ◽

C. Farquharson ◽

J. L. Millán ◽

...

Keyword(s):

Fracture Healing ◽

Bone Fracture ◽

Healing Process ◽

Bone Volume ◽

Fracture Repair ◽

Bending Test ◽

Bone Fracture Healing ◽

Trabecular Thickness ◽

Three Point Bending ◽

Normal Bone

Objectives Bone fracture healing is regulated by a series of complex physicochemical and biochemical processes. One of these processes is bone mineralization, which is vital for normal bone development. Phosphatase, orphan 1 (PHOSPHO1), a skeletal tissue-specific phosphatase, has been shown to be involved in the mineralization of the extracellular matrix and to maintain the structural integrity of bone. In this study, we examined how PHOSPHO1 deficiency might affect the healing and quality of fracture callus in mice. Methods Tibial fractures were created and then stabilized in control wild-type (WT) and Phospho1-/- mice (n = 16 for each group; mixed gender, each group carrying equal number of male and female mice) at eight weeks of age. Fractures were allowed to heal for four weeks and then the mice were euthanized and their tibias analyzed using radiographs, micro-CT (μCT), histology, histomorphometry and three-point bending tests. Results The μCT and radiographic analyses revealed a mild reduction of bone volume in Phospho1-/- callus, although it was not statistically significant. An increase in trabecular number and a decrease in trabecular thickness and separation were observed in Phospho1-/- callus in comparison with the WT callus. Histomorphometric analyses showed that there was a marked increase of osteoid volume over bone volume in the Phospho1-/- callus. The three-point bending test showed that Phospho1-/- fractured bone had more of an elastic characteristic than the WT bone. Conclusion Our work suggests that PHOSPHO1 plays an integral role during bone fracture repair and may be a therapeutic target to improve the fracture healing process. Cite this article: M. W. Morcos, H. Al-Jallad, J. Li, C. Farquharson, J. L. Millán, R. C. Hamdy, M. Murshed. PHOSPHO1 is essential for normal bone fracture healing: An Animal Study. Bone Joint Res 2018;7:397–405. DOI: 10.1302/2046-3758.76.BJR-2017-0140.R2.

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