-
Journal of Orthopaedic Research :... May 2020C1q/TNF-related protein 3 (CTRP3) is a cytokine known to regulate a variety of metabolic processes. Though previously undescribed in the context of bone regeneration,...
C1q/TNF-related protein 3 (CTRP3) is a cytokine known to regulate a variety of metabolic processes. Though previously undescribed in the context of bone regeneration, high throughput gene expression experiments in mice identified CTRP3 as one of the most highly upregulated genes in fracture callus tissue. Hypothesizing a positive regulatory role for CTRP3 in bone regeneration, we phenotyped skeletal development and fracture healing in CTRP3 knockout (KO) and CTRP3 overexpressing transgenic (TG) mice relative to wild-type (WT) control animals. CTRP3 KO mice experienced delayed endochondral fracture healing, resulting in abnormal mineral distribution, the presence of periosteal marrow compartments, and a nonunion-like state. Decreased osteoclast number was also observed in CTRP3 KO mice, whereas CTRP3 TG mice underwent accelerated callus remodeling. Gene expression profiling revealed a broad impact on osteoblast/osteoclast lineage commitment and metabolism, including arrested progression toward mature skeletal lineages in the KO group. A single systemic injection of CTRP3 protein at the time of fracture was insufficient to phenocopy the chronic TG healing response in WT mice. By associating CTRP3 levels with fracture healing progression, these data identify a novel protein family with potential therapeutic and diagnostic value. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:00-19966, 2020.
Topics: Adipokines; Animals; Bone Remodeling; Bony Callus; Cell Line; Fracture Healing; Humans; Mice, Inbred C57BL; Mice, Knockout
PubMed: 31808575
DOI: 10.1002/jor.24553 -
Journal of Bone and Mineral Research :... Nov 2021Nonunion is defined as the permanent failure of a fractured bone to heal, often necessitating surgical intervention. Atrophic nonunions are a subtype that are...
Nonunion is defined as the permanent failure of a fractured bone to heal, often necessitating surgical intervention. Atrophic nonunions are a subtype that are particularly difficult to treat. Animal models of atrophic nonunion are available; however, these require surgical or radiation-induced trauma to disrupt periosteal healing. These methods are invasive and not representative of many clinical nonunions where osseous regeneration has been arrested by a "failure of biology". We hypothesized that arresting osteoblast cell proliferation after fracture would lead to atrophic nonunion in mice. Using mice that express a thymidine kinase (tk) "suicide gene" driven by the 3.6Col1a1 promoter (Col1-tk), proliferating osteoblast lineage cells can be ablated upon exposure to the nucleoside analog ganciclovir (GCV). Wild-type (WT; control) and Col1-tk littermates were subjected to a full femur fracture and intramedullary fixation at 12 weeks age. We confirmed abundant tk+ cells in fracture callus of Col-tk mice dosed with water or GCV, specifically many osteoblasts, osteocytes, and chondrocytes at the cartilage-bone interface. Histologically, we observed altered callus composition in Col1-tk mice at 2 and 3 weeks postfracture, with significantly less bone and more fibrous tissue. Col1-tk mice, monitored for 12 weeks with in vivo radiographs and micro-computed tomography (μCT) scans, had delayed bone bridging and reduced callus size. After euthanasia, ex vivo μCT and histology showed failed union with residual bone fragments and fibrous tissue in Col1-tk mice. Biomechanical testing showed a failure to recover torsional strength in Col1-tk mice, in contrast to WT. Our data indicates that suppression of proliferating osteoblast-lineage cells for at least 2 weeks after fracture blunts the formation and remodeling of a mineralized callus leading to a functional nonunion. We propose this as a new murine model of atrophic nonunion. © 2021 American Society for Bone and Mineral Research (ASBMR).
Topics: Animals; Bony Callus; Disease Models, Animal; Femoral Fractures; Fracture Healing; Mice; Osteoblasts; X-Ray Microtomography
PubMed: 34405443
DOI: 10.1002/jbmr.4424 -
BMJ Case Reports Feb 2021Fracture healing has four phases: haematoma formation, soft callus, hard callus and remodelling. Often, non-healing fractures have an arrest of one of these phases,...
Fracture healing has four phases: haematoma formation, soft callus, hard callus and remodelling. Often, non-healing fractures have an arrest of one of these phases, which need resurgery. We have repurposed denosumab for impaired fracture healing cases to avoid surgical intervention. Here, we report a series of three cases of impaired fracture healing where denosumab was given 120 mg subcutaneous dosages for 3 months to enhance healing. All the three cases have shown complete bone union at a mean follow-up of 6.7 months (5-9 months) as assessed clinically and radiologically, and have observed no adverse effect of the therapy. Denosumab given in this dose aids fracture healing by increasing callus volume, density and bridges the fracture gap in recalcitrant fracture healing cases where the callus fails to consolidate.
Topics: Adult; Bone Density Conservation Agents; Bony Callus; Denosumab; Femoral Fractures; Fracture Fixation, Internal; Fracture Healing; Fractures, Closed; Fractures, Ununited; Humans; Humeral Fractures; Male; Middle Aged; Reoperation; Young Adult
PubMed: 33558382
DOI: 10.1136/bcr-2020-238460 -
European Review For Medical and... Mar 2018To monitor morphological feature and related osteogenic and bone metabolic change during healing of tibia fracture in a rat model.
OBJECTIVE
To monitor morphological feature and related osteogenic and bone metabolic change during healing of tibia fracture in a rat model.
MATERIALS AND METHODS
Tibia density and trabecular thickness were evaluated. Histopathology was examined by HE staining. Serous inflammatory factors IL-4, IL-6, TNF-α and metabolic biomarkers ALP, β-CTX, P1NP, were determined by ELISA. The expression of RUNX2, TGF-β1, VEGF-α, BMP-2, BMP-4, and BMP-7 in callus tissue were qualified by RT-PCR.
RESULTS
Bone density decreased until week 4 and then increased post-operation. Trabeculae in callus were thickened over time with active osteogenesis. ELISA indicated the most severe inflammation at week 2, with the highest level of TNF-α, IL-6, and the lowest level of IL-4. After 4 weeks, the inflammation was alleviated accompanying with the decline of TNF-α and IL-6, while there was the elevation of IL-4. Bone metabolism showed active osteogenesis and resorption at week 6 with high P1NP and β-CTX. The expression of RUNX2, TGF-β1, VEGF-α, BMP-2, BMP-4, and BMP-7 increased progressively from week 1 to 6. The major lesions at week 2 in sham were tissue necrosis, periosteal reactive hyperplasia, inflammatory cell infiltration, capillary hyperplasia and slight fibro-blast cytopoiesis. At week 4, proliferation was greatly activated, fibrous callus shaped and chondrogenesis and some osteogenesis occurred at week 8.
CONCLUSIONS
In rat model, bone density started to increase at week 6 after fracture, accompanied with trabeculae thickening, serous inflammatory factors decline, and peaked bone morphogenetic protein/growth factors, which indicated active osteogenesis was conforming to the classical phase of secondary fracture healing.
Topics: Animals; Bone Density; Bone Morphogenetic Proteins; Bony Callus; Fracture Healing; Osteogenesis; Rats; Rats, Sprague-Dawley; Tibia; Tibial Fractures
PubMed: 29565479
DOI: 10.26355/eurrev_201803_14463 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Sep 2021To explore the nature of micromovement and the biomechanical staging of fracture healing. (Review)
Review
OBJECTIVE
To explore the nature of micromovement and the biomechanical staging of fracture healing.
METHODS
Through literature review and theoretical analysis, the difference in micromovement research was taken as the breakthrough point to try to provide a new understanding of the role of micromovement and the mechanical working mode in the process of fracture healing.
RESULTS
The process of fracture healing is the process of callus generation and connection. The micromovement is the key to start the growth of callus, and the total amount of callus should be matched with the size of the fracture space. The strain at the fracture end is the key to determine the callus connection. The strain that can be tolerated by different tissues in the fracture healing process will limit the micromovement. According to this, the fracture healing process can be divided into the initiation period, perfusion period, contradiction period, connection period, and physiological period, i.e., the biomechanical staging of fracture healing.
CONCLUSION
Biomechanical staging of fracture healing incorporates important mechanical parameters affecting fracture healing and introduces the concepts of time and space, which helps to understand the role of biomechanics, and its significance needs further clinical test and exploration.
Topics: Biomechanical Phenomena; Bony Callus; Fracture Healing; Fractures, Bone; Humans
PubMed: 34523290
DOI: 10.7507/1002-1892.202103050 -
The Journal of Clinical Investigation Apr 2022Increased age is blamed for a wide range of bone physiological changes, and although the underlying mechanisms affecting the decreased capacity for fracture healing are...
Increased age is blamed for a wide range of bone physiological changes, and although the underlying mechanisms affecting the decreased capacity for fracture healing are not fully understood, they are clearly linked to changes at the cellular level. Recent evidence suggests potential roles of senescent cells in response to most tissue injuries, including bone fractures. In this issue of the JCI, Liu, Zhang, and co-authors showed that a senolytic drug cocktail cleared senescent cells from the callus and improved bone fracture repair in aged mice. Understanding how senescent cells emerge at fracture sites and how their timely removal improves fracture healing should provide insights for effective therapeutic approaches in old age.
Topics: Aging; Animals; Bony Callus; Fracture Healing; Fractures, Bone; Mice
PubMed: 35426369
DOI: 10.1172/JCI158871 -
Journal of Molecular Neuroscience : MN Aug 2021Pituitary adenylate cyclase-activating polypeptide (PACAP) is a naturally secreted signaling peptide and has important regulatory roles in the differentiation of the...
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a naturally secreted signaling peptide and has important regulatory roles in the differentiation of the central nervous system and its absence results in disorders in femur development. PACAP has an important function in prevention of oxidative stress or mechanical stress in chondrogenesis but little is known about its function in bone regeneration. A new callus formation model was set to investigate its role in bone remodeling. Fracturing was 5 mm distal from the proximal articular surface of the tibia and the depth was 0.5 mm. Reproducibility of callus formation was investigated with CT 3, 7, and 21 days after the operation. Absence of PACAP did not alter the alkaline phosphatase (ALP) activation in PACAP KO healing process. In developing callus, the expression of collagen type I increased in wild-type (WT) and PACAP KO mice decreased to the end of healing process. Expression of the elements of BMP signaling was disturbed in the callus formation of PACAP KO mice, as bone morphogenic protein 4 (BMP4) and 6 showed an early reduction in bone regeneration. However, elevated Smad1 expression was demonstrated in PACAP KO mice. Our results indicate that PACAP KO mice show various signs of disturbed bone healing and suggest PACAP compensatory and fine tuning effects in proper bone regeneration.
Topics: Animals; Bone Morphogenetic Protein 4; Bone Regeneration; Bony Callus; Cells, Cultured; Collagen Type I; Mice; Pituitary Adenylate Cyclase-Activating Polypeptide; Smad1 Protein
PubMed: 31808034
DOI: 10.1007/s12031-019-01448-z -
Journal of Bone and Mineral Research :... Oct 2005Standardized methods for the histomorphometric assessment of bone are essential features of most studies of metabolic bone diseases and their treatments. These... (Review)
Review
Standardized methods for the histomorphometric assessment of bone are essential features of most studies of metabolic bone diseases and their treatments. These methodologies were developed to assess coupled remodeling, focusing primarily on osteoblasts and osteoclasts, the anabolic and catabolic rates of these cells, and structural features of mature bone. Research studies on bone healing and the development of new therapeutic approaches for the enhancement of bone repair also require a comprehensive understanding of the basic cellular and tissue level mechanisms that underlie these processes. However, the histological methods developed for metabolic bone disease studies are not completely suitable for studies of bone repair because they are based on assumptions that there is little variation in tissue composition within a sample of bone and not generally designed to quantify other types of tissues, such as cartilage, that contribute to bone healing. These techniques also do not provide tissue-based structural measurements that are relatable to the specific types of biomechanical and radiographic structural assessments that are used to determine rates of bone healing. These deficiencies in current histological approaches therefore point to the need to establish standardized criteria for the histomorphometric assessments that are specifically adapted for the study of bone repair in models of fracture healing and bone regeneration. In this Perspective, we outline what we believe to be the specific structural, tissue. and cellular aspects that need to be addressed to establish these standardized criteria for the histomorphometric assessment of bone repair. We present the specific technical considerations that need to be addressed to appropriately sample repair tissues to obtain statistically meaningful results and suggest specific procedures and definitions of nomenclatures for the application of this technology to bone repair. Finally, we present how aspects of histomorphometric measurements of bone repair can be related to biomechanical and radiographic imaging properties that functionally define rates of bone healing, and thus, how these tools can be used to provide corroborating data.
Topics: Animals; Bone Density; Bone Diseases, Metabolic; Bone Regeneration; Bony Callus; Fracture Healing; Humans; Image Cytometry; Image Processing, Computer-Assisted; Mice; Radiography; Rats
PubMed: 16160729
DOI: 10.1359/JBMR.050702 -
Clinical Interventions in Aging 2018The objective of the study was to investigate the effects of glucocorticoid (GC) on the fracture healing process in a closed femur fracture mice model.
BACKGROUND
The objective of the study was to investigate the effects of glucocorticoid (GC) on the fracture healing process in a closed femur fracture mice model.
MATERIALS AND METHODS
Forty 12-week-old female CD-1 mice were randomly allocated into four groups: healthy control and mice with prednisone exposure (oral gavage), 6 mg/kg/day (GC-L), 9 mg/kg/day (GC-M) and 12 mg/kg/day (GC-H). Three weeks after the initiation of prednisone dosing, closed femur fractures were created on prednisone-exposed mice and the healthy control. Prednisone administration was continued for 9 weeks post-fracture, and X-ray imaging was performed weekly to monitor the fracture healing process until the mice were euthanized. Necropsy was performed after 9 weeks and the fractured femurs were isolated and processed at necropsy for micro-CT and biomechanical property analysis. Another 20 mice (control and GC-H, 10 mice/group) were used for histology and micro-CT analysis at early time point (2-week post fracture) with continued prednisone exposure.
RESULTS
The results showed that oral administration of prednisone for 3 months in this strain of mice could inhibit endochondral ossification and delay the healing process, especially hard callus formation (woven bone) and bone remodeling during healing. It also could significantly decrease bone biomechanical properties.
CONCLUSION
Long-term GC administration leads to significantly delayed fracture healing and impaired bone biomechanical properties. This mouse model may be used to systematically study the cellular and molecular mechanisms underlying fracture healing with GC treatment background and may also be used to study the influence of different therapeutic interventions for bone fracture healing.
Topics: Animals; Biomechanical Phenomena; Bone Remodeling; Bony Callus; Disease Models, Animal; Female; Femoral Fractures; Fracture Healing; Glucocorticoids; Mice; Osteogenesis; Prednisone; Random Allocation; X-Ray Microtomography
PubMed: 30197508
DOI: 10.2147/CIA.S167431 -
Molecular Medicine Reports May 2017Fracture healing involves the coordinated actions of multiple cytokines. Bone morphogenetic protein 9 (BMP9) is an important factor in bone formation. The present study...
Fracture healing involves the coordinated actions of multiple cytokines. Bone morphogenetic protein 9 (BMP9) is an important factor in bone formation. The present study aimed to investigate the osteogenic potential of bone marrow stem cells (BMSCs) in response to adenoviral (Ad)BMP9, and the early fracture repair properties of AdBMP9 in surgically‑created fractures in osteoporotic rats. Alkaline phosphatase (ALP) activity was assayed and matrix mineralization was examined by Alizarin Red S staining. mRNA and protein expression levels of BMP9, runt‑related transcription factor 2 (RUNX2) and type 1 collagen (COL‑1) were detected in vitro and in vivo. Femoral bone mineral density was assessed for osteoporosis in ovariectomized rats. An open femora fracture was subsequently created, and gelatin sponges containing AdBMP9 were implanted. The femora were harvested for radiographical, micro‑computed tomography, biomechanical and histological analysis 4 weeks later. BMP9 successfully increased ALP activity and induced mineralized nodule formation in BMSCs. BMP9 in gelatin sponges demonstrated marked effects on microstructural parameters and the biomechanical strength of bone callus. In addition, it upregulated the expression levels of RUNX2 and COL‑1. AdBMP9 in gelatin sponges significantly mediated callus formation, and increased bone mass and strength in osteoporotic rats with femora fractures. The results of the present study suggested that BMP9 enhanced callus formation and maintained early mechanical stability during fracture healing in osteoporotic rats, implicating it as a potential novel therapeutic target for fracture healing.
Topics: Adenoviridae; Animals; Bony Callus; Female; Femoral Fractures; Fracture Healing; Growth Differentiation Factor 2; Osteoporosis; Rats; Rats, Sprague-Dawley; Transduction, Genetic
PubMed: 28447742
DOI: 10.3892/mmr.2017.6302