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Bone Healing and Hormonal Bioassay in Patients with Long-Bone Fractures and Concomitant Head Injury.Medical Principles and Practice :... 2016The aim of this study is to investigate healing of fractures in patients with concomitant head injuries and to measure blood hormone levels to elucidate the mechanism of...
OBJECTIVE
The aim of this study is to investigate healing of fractures in patients with concomitant head injuries and to measure blood hormone levels to elucidate the mechanism of a possible accelerated osteogenesis.
MATERIALS AND METHODS
One hundred and sixty-two patients were included in this study and divided into 3 cohorts: group A with head injuries only (n = 52); group B with head injuries as well as long-bone fractures (n = 50); group C with long-bone fractures only (n = 60). Fracture-healing parameters including time of appearance and thickness of the bridging callus, and blood hormonal assays were measured and compared using Student's t test.
RESULTS
The mean time to healing was significantly lower in cohort B (6.9 ± 2.9 weeks) than C (22.4 ± 8.7 weeks; p = 0.001). The mean thickness of the healing callus was significantly higher in cohort B (26.3 ± 9.7 mm) than C (8.1 ± 5.9 mm; p = 0.002). The mean healing rate was also higher in cohort B (4.5 ± 2.3 mm/week) than C (0.38 ± 0.21 mm/week; p = 0.001). Blood hormonal assays in group B showed higher values of parathyroid hormone and growth hormone than in group C. However, adrenaline and noradrenaline values were lower in group B than in group C at all measured time intervals, and correspondingly leptin was lower in all groups (p = 0.001). Corticosteroid values were normal in group B compared to slightly higher values in group C, also at all measured time intervals.
CONCLUSION
In this study, healing of fractures in patients with concomitant head injuries was accelerated, thereby indicating an involvement of a combined neurohormonal mechanism.
Topics: Adrenal Cortex Hormones; Adult; Bony Callus; Craniocerebral Trauma; Diaphyses; Female; Fracture Healing; Fractures, Bone; Glasgow Coma Scale; Growth Hormone; Humans; Male; Middle Aged; Osteogenesis; Parathyroid Hormone; Time Factors; Young Adult
PubMed: 26954461
DOI: 10.1159/000445250 -
Stem Cells (Dayton, Ohio) May 2023Regulator of G protein signaling 5 (RGS5) is a GTPase activator for heterotrimeric G-protein α-subunits, shown to be a marker of pericytes. Bone marrow stromal cell...
Regulator of G protein signaling 5 (RGS5) is a GTPase activator for heterotrimeric G-protein α-subunits, shown to be a marker of pericytes. Bone marrow stromal cell population (BMSCs) is heterogeneous. Populations of mesenchymal progenitors, cells supportive of hematopoiesis, and stromal cells regulating bone remodeling have been recently identified. Periosteal and bone marrow mesenchymal stem cells (MSCs) are participating in fracture healing, but it is difficult to distinguish the source of cells within the callus. Considering that perivascular cells exert osteoprogenitor potential, we generated an RGS5 transgenic mouse model (Rgs5-CreER) which when crossed with Ai9 reporter animals (Rgs5/Tomato), is suitable for lineage tracing during growth and post-injury. Flow cytometry analysis and histology confirmed the presence of Rgs5/Tomato+ cells within CD31+ endothelial, CD45+ hematopoietic, and CD31-CD45- mesenchymal/perivascular cells. A tamoxifen chase showed expansion of Rgs5/Tomato+ cells expressing osterix within the trabeculae positioned between mineralized matrix and vasculature. Long-term chase showed proportion of Rgs5/Tomato+ cells contributes to mature osteoblasts expressing osteocalcin. Following femoral fracture, Rgs5/Tomato+ cells are observed around newly formed bone within the BM cavity and expressed osterix and osteocalcin, while contribution within periosteum was low and limited to fibroblastic callus with very few positive chondrocytes. In addition, BM injury model confirmed that RGS5-Cre labels population of BMSCs expands during injury and participates in osteogenesis. Under homeostatic conditions, lineage-traced RGS5 cells within the trabecular area demonstrate osteoprogenitor capacity that in an injury model contributes to new bone formation primarily within the BM niche.
Topics: Mice; Animals; Osteocalcin; Bony Callus; Osteogenesis; Fracture Healing; Chondrocytes; Mice, Transgenic; Osteoblasts; RGS Proteins
PubMed: 36888549
DOI: 10.1093/stmcls/sxad020 -
Anatomical Record (Hoboken, N.J. : 2007) Dec 2018Computational simulations of fracture healing are a valuable tool to improve fracture treatment and implants. Several finite-element models have been established to...
Computational simulations of fracture healing are a valuable tool to improve fracture treatment and implants. Several finite-element models have been established to predict callus formation due to mechanobiological rules. This work provides a comprehensive simulation for virtual implantation through the combination of callus simulation and finite-element structural synthesis (FESS) of (re-)modeling during and after healing based on Pauwel's theory of histogenesis and Wolff's law. The simulation is based on a linear elastic material model and includes generation of fracture hematoma and initial mesenchymal stem cell concentration out of an unspecified solid, cell proliferation, migration, and differentiation due to mechanical stimuli and time-dependent axial loading. Three nondisplaced femoral shaft fractures with initial interfragmentary movement of 0.2, 0.6, and 1 mm and one fracture with 4 mm translation are modeled. The predictions of interfragmentary movement during fracture healing, healing success, and healing time agree with observed clinical outcome, animal models, and other numerical models. Initial interfragmentary movement between 0.2 and 1 mm leads to healing success, with the fastest healing occurring at 0.2 mm. The model of the dislocated fractures shows no further bending after remodeling and is loaded with physiological stress of -13 MPa. Ideal load-time graphs may give insight into the bone's ability to withstand loads as healing time progresses, and thus holds potential for applications in rehabilitation planning. Better knowledge of the forces present during fracture healing is needed to deploy simulations for surgical planning and manufacturing of patient individualized implants. Anat Rec, 301:2112-2121, 2018. © 2018 Wiley Periodicals, Inc.
Topics: Animals; Biomechanical Phenomena; Bone Remodeling; Bony Callus; Finite Element Analysis; Fracture Healing; Fractures, Bone; Humans; Models, Biological
PubMed: 30290071
DOI: 10.1002/ar.23893 -
Journal of Bone and Mineral Research :... Jan 2021In response to bone fracture, periosteal progenitor cells proliferate, expand, and differentiate to form cartilage and bone in the fracture callus. These cellular...
In response to bone fracture, periosteal progenitor cells proliferate, expand, and differentiate to form cartilage and bone in the fracture callus. These cellular functions require the coordinated activation of multiple transcriptional programs, and the transcriptional regulators Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) regulate osteochondroprogenitor activation during endochondral bone development. However, recent observations raise important distinctions between the signaling mechanisms used to control bone morphogenesis and repair. Here, we tested the hypothesis that YAP and TAZ regulate osteochondroprogenitor activation during endochondral bone fracture healing in mice. Constitutive YAP and/or TAZ deletion from Osterix-expressing cells impaired both cartilage callus formation and subsequent mineralization. However, this could be explained either by direct defects in osteochondroprogenitor differentiation after fracture or by developmental deficiencies in the progenitor cell pool before fracture. Consistent with the second possibility, we found that developmental YAP/TAZ deletion produced long bones with impaired periosteal thickness and cellularity. Therefore, to remove the contributions of developmental history, we next generated adult onset-inducible knockout mice (using Osx-Cre ) in which YAP and TAZ were deleted before fracture but after normal development. Adult onset-induced YAP/TAZ deletion had no effect on cartilaginous callus formation but impaired bone formation at 14 days post-fracture (dpf). Earlier, at 4 dpf, adult onset-induced YAP/TAZ deletion impaired the proliferation and expansion of osteoblast precursor cells located in the shoulder of the callus. Further, activated periosteal cells isolated from this region at 4 dpf exhibited impaired osteogenic differentiation in vitro upon YAP/TAZ deletion. Finally, confirming the effects on osteoblast function in vivo, adult onset-induced YAP/TAZ deletion impaired bone formation in the callus shoulder at 7 dpf before the initiation of endochondral ossification. Together, these data show that YAP and TAZ promote the expansion and differentiation of periosteal osteoblast precursors to accelerate bone fracture healing. © 2020 American Society for Bone and Mineral Research (ASBMR).
Topics: Animals; Bony Callus; Cell Differentiation; Fractures, Bone; Mice; Osteoblasts; Osteogenesis
PubMed: 32835424
DOI: 10.1002/jbmr.4166 -
Nature Communications May 2021Bone regenerates by activation of tissue resident stem/progenitor cells, formation of a fibrous callus followed by deposition of cartilage and bone matrices. Here, we...
Bone regenerates by activation of tissue resident stem/progenitor cells, formation of a fibrous callus followed by deposition of cartilage and bone matrices. Here, we show that mesenchymal progenitors residing in skeletal muscle adjacent to bone mediate the initial fibrotic response to bone injury and also participate in cartilage and bone formation. Combined lineage and single-cell RNA sequencing analyses reveal that skeletal muscle mesenchymal progenitors adopt a fibrogenic fate before they engage in chondrogenesis after fracture. In polytrauma, where bone and skeletal muscle are injured, skeletal muscle mesenchymal progenitors exhibit altered fibrogenesis and chondrogenesis. This leads to impaired bone healing, which is due to accumulation of fibrotic tissue originating from skeletal muscle and can be corrected by the anti-fibrotic agent Imatinib. These results elucidate the central role of skeletal muscle in bone regeneration and provide evidence that skeletal muscle can be targeted to prevent persistent callus fibrosis and improve bone healing after musculoskeletal trauma.
Topics: Animals; Bone Regeneration; Bony Callus; Cell Differentiation; Cells, Cultured; Fracture Healing; Fractures, Bone; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Fluorescence; Muscle, Skeletal; Osteogenesis; Mice
PubMed: 34001878
DOI: 10.1038/s41467-021-22842-5 -
Journal of Orthopaedic Research :... Aug 2021The majority of fracture research has been conducted using long bone fracture models, with significantly less research into the mechanisms driving craniofacial repair....
The majority of fracture research has been conducted using long bone fracture models, with significantly less research into the mechanisms driving craniofacial repair. However, craniofacial bones differ from long bones in both their developmental mechanism and embryonic origin. Thus, it is possible that their healing mechanisms could differ. In this study we utilize stabilized and unstabilized mandible fracture models to investigate the pathways regulating repair. Whereas fully stable trephine defects in the ramus form bone directly, mechanical motion within a transverse fracture across the same anatomical location promoted robust cartilage formation before boney remodeling. Literature investigating long bone fractures show chondrocytes are a direct precursor of osteoblasts during endochondral repair. Lineage tracing with Aggrecan-Cre ::Ai9 tdTomato mice demonstrated that mandibular callus chondrocytes also directly contribute to the formation of new bone. Furthermore, immunohistochemistry revealed that chondrocytes located at the chondro-osseous junction expressed Sox2, suggesting that plasticity of these chondrocytes may facilitate this chondrocyte-to-osteoblast transformation. Based on the direct role chondrocytes play in bone repair, we tested the efficacy of cartilage grafts in healing critical-sized mandibular defects. Whereas empty defects remained unbridged and filled with fibrous tissue, cartilage engraftment produced bony-bridging and robust marrow cavity formation, indicating healthy vascularization of the newly formed bone. Engrafted cartilage directly contributed to new bone formation since a significant portion of the newly formed bone was graft/donor-derived. Taken together these data demonstrate the important role of chondrocyte-to-osteoblast transformation during mandibular endochondral repair and the therapeutic promise of using cartilage as a tissue graft to heal craniofacial defects.
Topics: Animals; Bony Callus; Chondrocytes; Fracture Healing; Mandibular Fractures; Mice; Osteoblasts; Osteogenesis
PubMed: 33140859
DOI: 10.1002/jor.24904 -
Biomolecules Apr 2020Green tea drinking can ameliorate postmenopausal osteoporosis by increasing the bone mineral density. (-)-Epigallocatechin-3-gallate (EGCG), the abundant and active...
Green tea drinking can ameliorate postmenopausal osteoporosis by increasing the bone mineral density. (-)-Epigallocatechin-3-gallate (EGCG), the abundant and active compound of tea catechin, was proven to be able to reduce bone loss and ameliorate microarchitecture in female ovariectomized rats. EGCG can also enhance the osteogenic differentiation of murine bone marrow mesenchymal stem cells and inhibit the osteoclastogenesis in RAW264.7 cells by modulation of the receptor activator of nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegrin (OPG) (RANK/RANKL/OPG) pathway. Our previous study also found that EGCG can promote bone defect healing in the distal femur partially via bone morphogenetic protein-2 (BMP-2). Considering the osteoinduction property of BMP-2, we hypothesized that EGCG could accelerate the bone healing process with an increased expression of BMP-2. In this manuscript, we studied whether the local use of EGCG can facilitate tibial fracture healing. Fifty-six 4-month-old rats were randomly assigned to two groups after being weight-matched: a control group with vehicle treatment (Ctrl) and a study group with 10 µmol/L, 40 µL, EGCG treatment (EGCG). Two days after the operation, the rats were treated daily with EGCG or vehicle by percutaneous local injection for 2 weeks. The application of EGCG enhanced callus formation by increasing the bone volume and subsequently improved the mechanical properties of the tibial bone, including the maximal load, break load, stiffness, and Young's modulus. The results of the histology and BMP-2 immunohistochemistry staining showed that EGCG treatment accelerated the bone matrix formation and produced a stronger expression of BMP-2. Taken together, this study for the first time demonstrated that local treatment of EGCG can accelerate the fracture healing process at least partly via BMP-2.
Topics: Animals; Biomechanical Phenomena; Bony Callus; Catechin; Fracture Healing; Male; Rats, Sprague-Dawley; Tea; Tibia; Tibial Fractures; X-Ray Microtomography
PubMed: 32316306
DOI: 10.3390/biom10040620 -
Critical Reviews in Eukaryotic Gene... 2010The failure of an osseous fracture to heal, or the development of a nonunion, is common; however, current diagnostic measures lack the capability of early and reliable... (Review)
Review
The failure of an osseous fracture to heal, or the development of a nonunion, is common; however, current diagnostic measures lack the capability of early and reliable detection of such events. Analyses of radiographic imaging and clinical examination, in combination, remain the gold standard for diagnosis; however, these methods are not reliable for early detection. Delayed diagnosis of a nonunion is costly from both the patient and treatment standpoints. In response, repeated efforts have been made to identify bone metabolic markers as diagnostic or prognostic tools for monitoring bone healing. Thus far, the evidence regarding a correlation between the kinetics of most bone metabolic markers and nonunion is very limited. With the aim of classifying the role of biological pathways of bone metabolism and of understanding bone conditions in the development of osteoporosis, advances have been made in our knowledge of the molecular basis of bone remodeling, fracture healing, and its failure. Procollagen type I amino-terminal propeptide has been shown to be a reliable bone formation marker in osteoporosis therapy and its kinetics during fracture healing has been recently described. In this article, we suggest that procollagen type I amino-terminal propeptide presents a good opportunity for early detection of nonunion. We also review the role and potential of serum PINP, as well as other markers, as indications of fracture healing.
Topics: Biomarkers; Bony Callus; Fracture Healing; Humans; Osteogenesis; Osteoporosis; Prognosis
PubMed: 21133841
DOI: 10.1615/critreveukargeneexpr.v20.i2.20 -
Bone Feb 2021Interleukin-6 (IL-6) is highly upregulated in response to skeletal injury, suggesting it plays a role in the inflammatory phase of fracture repair. However, the impact...
Interleukin-6 (IL-6) is highly upregulated in response to skeletal injury, suggesting it plays a role in the inflammatory phase of fracture repair. However, the impact of IL-6 on successful repair remains incompletely defined. Therefore, we investigated the role of IL-6 in two models of fracture repair (full fracture and stress fracture) using 12-week old IL-6 global knockout mice (IL-6 KO) and wild type (WT) littermate controls. Callus morphology and mineral density 14 days after full femur fracture did not differ between IL-6 knockout mice and controls. In contrast, IL-6 KO mice had an enhanced bone response 7 days after ulnar stress fracture compared to WT, with increased total callus volume (p = 0.020) and callus bone volume (p = 0.045). IL-6 KO did not alter the recruitment of immune cells (Gr-1 or F4/80 positive) to the stress fracture callus. IL-6 KO also did not alter the number of osteoclasts in the stress fracture callus. Using RNA-seq, we identified differentially expressed genes in stress fracture vs. contralateral control ulnae, and observed that IL-6 KO resulted in only modest alterations to the gene expression response to stress fracture (SFx). Wnt1 was more highly upregulated in IL-6 KO SFx callus at both day 1 (fold change 12.5 in KO vs. 5.7 in WT) and day 3 (fold change 4.7 in KO vs. 1.9 in WT). Finally, using tibial compression to induce bone formation without bone injury, we found that IL-6 KO directly impacted osteoblast function, increasing the propensity for woven bone formation. In summary, we report that IL-6 knockout enhanced formation of callus and bone following stress fracture injury, likely through direct action on the osteoblast's ability to produce woven bone. This suggests a novel role of IL-6 as a suppressor of intramembranous bone formation.
Topics: Animals; Bony Callus; Fracture Healing; Fractures, Stress; Interleukin-6; Mice; Mice, Knockout; Osteogenesis
PubMed: 33181349
DOI: 10.1016/j.bone.2020.115737 -
Clinical Orthopaedics and Related... Nov 2014Poor fracture healing in geriatric populations is a significant source of morbidity, mortality, and cost to individuals and society; however, a fundamental biologic...
BACKGROUND
Poor fracture healing in geriatric populations is a significant source of morbidity, mortality, and cost to individuals and society; however, a fundamental biologic understanding of age-dependent healing remains elusive. The development of an aged-based fracture model system would allow for a mechanistic understanding that could guide future biologic treatments.
QUESTIONS/PURPOSES
Using a small animal model of long-bone fracture healing based on chronologic age, we asked how aging affected (1) the amount, density, and proportion of bone formed during healing; (2) the amount of cartilage produced and the progression to bone during healing; (3) the callus structure and timing of the fracture healing; and (4) the behavior of progenitor cells relative to the observed deficiencies of geriatric fracture healing.
METHODS
Transverse, traumatic tibial diaphyseal fractures were created in 5-month-old (n=104; young adult) and 25-month-old (n=107; which we defined as geriatric, and are approximately equivalent to 70-85 year-old humans) C57BL/6 mice. Fracture calluses were harvested at seven times from 0 to 40 days postfracture for micro-CT analysis (total volume, bone volume, bone volume fraction, connectivity density, structure model index, trabecular number, trabecular thickness, trabecular spacing, total mineral content, bone mineral content, tissue mineral density, bone mineral density, degree of anisotropy, and polar moment of inertia), histomorphometry (total callus area, cartilage area, percent of cartilage, hypertrophic cartilage area, percent of hypertrophic cartilage area, bone and osteoid area, percent of bone and osteoid area), and gene expression quantification (fold change).
RESULTS
The geriatric mice produced a less robust healing response characterized by a pronounced decrease in callus amount (mean total volume at 20 days postfracture, 30.08±11.53 mm3 versus 43.19±18.39 mm3; p=0.009), density (mean bone mineral density at 20 days postfracture, 171.14±64.20 mg hydroxyapatite [HA]/cm3 versus 210.79±37.60 mg HA/cm3; p=0.016), and less total cartilage (mean cartilage area at 10 days postfracture, 101,279±46,755 square pixels versus 302,167±137,806 square pixels; p=0.013) and bone content (mean bone volume at 20 days postfracture, 11.68±3.18 mm3 versus 22.34±10.59 mm3; p<0.001) compared with the young adult mice. However, the amount of cartilage and bone relative to the total callus size was similar between the adult and geriatric mice (mean bone volume fraction at 25 days postfracture, 0.48±0.10 versus 0.50±0.13; p=0.793), and the relative expression of chondrogenic (mean fold change in SOX9 at 10 days postfracture, 135+25 versus 90±52; p=0.221) and osteogenic genes (mean fold change in osterix at 20 days postfracture, 22.2±5.3 versus 18.7±5.2; p=0.324) was similar. Analysis of mesenchymal cell proliferation in the geriatric mice relative to adult mice showed a decrease in proliferation (mean percent of undifferentiated mesenchymal cells staining proliferating cell nuclear antigen [PCNA] positive at 10 days postfracture, 25%±6.8% versus 42%±14.5%; p=0.047).
CONCLUSIONS
Our findings suggest that the molecular program of fracture healing is intact in geriatric mice, as it is in geriatric humans, but callus expansion is reduced in magnitude.
CLINICAL RELEVANCE
Our study showed altered healing capacity in a relevant animal model of geriatric fracture healing. The understanding that callus expansion and bone volume are decreased with aging can help guide the development of targeted therapeutics for these difficult to heal fractures.
Topics: Aging; Animals; Bone Density; Bone and Bones; Bony Callus; Cartilage; Disease Models, Animal; Fracture Healing; Fractures, Bone; Humans; Imaging, Three-Dimensional; Male; Mice; Mice, Inbred C57BL; Organ Size; Stem Cells; X-Ray Microtomography
PubMed: 25106797
DOI: 10.1007/s11999-014-3829-x