Normal Bone Healing Research Articles

Application of topical 5-Fluorouracil to reduce the recurrence of odontogenic keratocyst: A prospective study with 2-year follow-up

ObjectivesThe purpose of this prospective study was to evaluate the effect of topical 5-Fluorouracil as an adjunct therapy in reducing the recurrence of odontogenic keratocyst. MethodsForty-eight patients with proven incisional biopsy as odontogenic keratocyst were included in this clinical study. The patients were divided into two equal groups, the test group patients were treated with 5-Fluorouracil cream after cyst enucleation. However, the control group patients were treated with cyst enucleation only. Recurrence (yes/no) was the primary outcome variable evaluated by clinical signs of inflammation, swelling, or pain within a 2-year follow-up. The pain was measured on a visual analogue scale, and swelling was measured pre-surgically using vertical and horizontal references, 1 week, 1 month, 3 months, 6 months, 12 months, and 24 months. Computed tomography was performed pre-surgically and 24 hours post-surgically, at 12-month, and 24-month intervals to evaluate local bone density. The T-test was used to compare between two studied groups. ResultsPost-surgical follow-up showed uneventful wound healing in both groups with no clinical signs of recurrence or swelling, pain results demonstrated that patients have decreased records throughout the observation periods with no significant difference between both groups. Normal sensation was encountered in all patients except for one patient in the control group who showed no sensation (score 2). Post-surgical radiographic findings revealed a considerable shift in bone density in all patients of both groups at the site of excised lesions during the follow-up periods compared with immediate post-surgical radiographs. However, the test group patients demonstrated a significant increase of bone density between different evaluation periods (P = 0.001) than the control group. ConclusionConservative enucleation of odontogenic keratocyst combined with topical application of 5-Fluorouracil is an effective treatment with lower recurrence rates, less morbidity, and normal bone healing.

Lack of Nuclear Localization of the Creb3l1 Transcription Factor Causes Defects in Caudal Fin Bifurcation in Zebrafish Danio rerio.

The formation of normal bone and bone healing requires the cAMP-responsive element binding protein 3-like-1 (Creb3l1) transmembrane transcription factor, as deletion of the murine CREB3L1 results in osteopenic animals with limited capacity to repair bone after a fracture. Creb3l1 undergoes regulated intramembrane proteolysis (RIP) to release the N-terminal transcription activating (TA) fragment that enters the nucleus and regulates the expression of target genes. To expand our understanding of Creb3l1's role in skeletal development and skeletal patterning, we aimed to generate animals expressing only the TA fragment of Creb3l1 lacking the transmembrane domain and thereby not regulated through RIP. However, the CRISPR/Cas9-mediated genome editing in zebrafish Danio rerio caused a frameshift mutation that added 56 random amino acids at the C-terminus of the TA fragment (TA+), making it unable to enter the nucleus. Thus, TA+ does not regulate transcription, and the creb3l1TA+/TA+ fish do not mediate creb3l1-dependent transcription. We document that the creb3l1TA+/TA+ fish exhibit defects in the patterning of caudal fin lepidotrichia, with significantly distalized points of proximal bifurcation and decreased secondary bifurcations. Moreover, using the caudal fin amputation model, we show that creb3l1TA+/TA+ fish have decreased regeneration and that their regenerates replicate the distalization and bifurcation defects observed in intact fins of creb3l1TA+/TA+ animals. These defects correlate with altered expression of the shha and ptch2 components of the Sonic Hedgehog signaling pathway in creb3l1TA+/TA+ regenerates. Together, our results uncover a previously unknown intersection between Creb3l1 and the Sonic Hedgehog pathway and document a novel role of Creb3l1 in tissue patterning.

Application of mixed reality technology in free fibular flap transplantation for repairing mandibular defects

To explore the feasibility and effectiveness of mixed reality technology for localizing perforator vessels in the repair of mandibular defects using free fibular flap. Between June 2020 and June 2023, 12 patients with mandibular defects were repaired with free fibular flap. There were 8 males and 4 females, with an average age of 61 years (range, 35-78 years). There were 9 cases of ameloblastomas and 3 cases of squamous cell carcinomas involving the mandible. The disease duration ranged from 15 days to 2 years (median, 14.2 months). The length of mandibular defects ranged from 5 to 14 cm (mean, 8.5 cm). The area of soft tissue defects ranged from 5 cm×4 cm to 8 cm×6 cm. Preoperative enhanced CT scans of the maxillofacial region and CT angiography of the lower limbs were performed, and the data was used to create three-dimensional models of the mandible and lower limb perforator vessels. During operation, the mixed reality technology was used to overlay the three-dimensional model of perforator vessels onto the body surface for harvesting the free fibular flap. The length of the fibula harvested ranged from 6 to 15 cm, with a mean of 9.5 cm; the size of the flap ranged from 6 cm×5 cm to 10 cm×8 cm. The donor sites were sutured directly in 7 cases and repaired with free skin grafting in 5 cases. Thirty perforator vessels were located by mixed reality technology before operation, with an average of 2.5 vessels per case; the distance between the exit point of the perforator vessels located before operation and the actual exit point ranged from 1 to 4 mm, with a mean of 2.8 mm. All fibular flaps survived; 1 case had necrosis at the distal end of flap, which healed after dressing changes. One donor site had infection, which healed after anti-inflammatory dressing changes; the remaining incisions healed by first intention, and the grafts survived smoothly. All patients were followed up 8-36 months (median, 21 months). The repaired facial appearance was satisfactory, with no flap swelling. Among the patients underwent postoperative radiotherapy, 2 patients had normal bone healing and 1 had delayed healing at 6 months. In free fibular flap reconstruction of mandibular defects, the use of mixed reality technology for perforator vessel localization can achieve three-dimensional visualization, simplify surgical procedures, and reduce errors.

Assessment of CAD/CAM Customized V Pattern Plate Versus Standard Miniplates Fixation in Mandibular Angle Fracture (Randomized Clinical Trial)

BackgroundMandibular angle is the most common site for fractures, accounting for 23–42% of all cases of mandibular fractures. A customized fixation system is designed directly for a specific patient, which reduces the time spent bending and fixing the plate during the operation. This study was designed to assess the effect of CAD/CAM customized V pattern plate versus standard miniplates fixation in mandibular angle fracture.Materials and MethodsThis prospective randomized clinical trial included 26 patients suffering from mandibular angle fracture. Patients were selected from Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Cairo University and Ahmed Maher Teaching Hospital. Study group (13) needed open reduction and internal fixation by using CAD/CAM V plate with surgical guide, while control group (13) needed open reduction and internal fixation by using standard superior–inferior miniplate fixation. The patients were then followed up for one year postoperatively.ResultsIt showed that there was a statistical difference between the study group and the control group regarding postoperative pain, occlusion, and maximal interincisal opening (p value < 0.05%). There was no statistical difference (p value > 0.05%) in the postoperative panoramic radiograph that was taken within the postoperative 1st week in both groups, while the increase in mean bone density was statistically significant (p value < 0.05%) from 6 months to one year postoperatively.ConclusionCAD/CAM customized V pattern plate is a suitable plate design because it offers sufficient stability for normal bone healing, the creation of an ideal occlusion, an early return to function, and adequate postoperative radiographic outcomes.Trial RegistrationIt was registered at ClinicalTrials.gov. Registration number: NCT03761524. Registration date: 03.12.2018.

Medication-related osteonecrosis of the jaw using periodontitis-induced rat before tooth extraction

ObjectiveThis study aimed to investigate the occurrence of medication-related osteonecrosis of the jaw (MRONJ) after tooth extraction due to periodontitis in ovariectomized rats.MethodsTwenty-four osteoporosis-induced rats were administered with zoledronic acid (ZA; ZA group) or saline (CONT group). In both groups, tooth extraction was performed after inducing periodontitis, and all animals were sacrificed 8-week after tooth extraction.ResultsMicro-CT of the tibia showed that the bone volume fraction, bone surface density, trabecular number, and bone mineral density were significantly higher in the ZA group than in the CONT group. Histologically, the proliferative zone on the growth plate was thicker in the ZA group than in the CONT group. Micro-CT of the extraction sites revealed that the bone volume fraction was significantly higher in the ZA group than in the CONT group. Radiologically, the ZA group showed partial healing and delayed healing. Histological analysis revealed normal bone healing status with completely healed epithelium in the extraction sites of the CONT group, whereas abnormal empty osteocytes in the necrotic bone and inflammatory infiltration were observed in the ZA group.ConclusionThe incidence of MRONJ increased in the rats administered with ZA.

Non-psychoactive Cannabidiol Prevents Osteoporosis in an Animal Model and Increases Cell Viability, Proliferation, and Osteogenic Gene Expression in Human Skeletal Stem and Progenitor Cells.

Cannabidiol (CBD), the non-psychoactive component of the Cannabis sativa plant, is marketed as a potential therapeutic agent and has been studied for its roles in reducing inflammation and managing neuropathic pain. Some studies have reported that CB1 and CB2 receptor activation can attenuate and reverse bone loss in experimental animal models. Despite this, little is known about the impact of CBD on fracture healing. We investigated the effects of CBD in vitro using human osteoprogenitor cells and in vivo via murine femur fracture and osteoporosis models. In vitro mesenchymal stem cells were treated with increasing concentrations of crystalized pharmaceutical grade CBD or vehicle solution. Cell viability and proliferation were significantly increased in cells treated with CBD compared to vehicle control. Osteocalcin expression was also significantly higher in the CBD-treated human stem cells compared to vehicle control. In vivo the effect of CBD on bone mineral density and fracture healing in mice was examined using a two-phase experimental approach. Fluoxetine was used for pharmacologic induction of osteoporosis and surgical oophorectomy (OVX) was used for hormonal induction of osteoporosis. X-ray and microCT analysis showed that CBD prevented both fluoxetine- and OVX-induced osteoporosis. We found that while OVX resulted in delayed bone healing in control mice, CBD-pretreated mice exhibited normal bone healing. Collectively these in vitro and in vivo findings suggest that CBD exerts cell-specific effects which can be exploited to enhance bone metabolism. These findings also indicate that CBD usage in an osteoporotic population may positively impact bone morphology, warranting further research.

Microtomographic, histomorphometric, and molecular features show a normal alveolar bone healing process in iNOS-deficient mice along a compensatory upregulation of eNOS and nNOS isoforms.

Inducible nitric oxide synthase (iNOS) is one of the enzymes responsible for the synthesis of nitric oxide (NO), which is an important signaling molecule with effects on blood vessels, leukocytes, and bone cells. However, the role of iNOS in alveolar bone healing remains unclear. This study investigated the role of iNOS in alveolar bone healing after tooth extraction in mice. C57Bl/6 wild type (WT) and iNOS genetically deficient (iNOS-KO) mice were subjected to upper incision tooth extraction, and alveolar bone healing was evaluated by micro-computed tomography (μCT) and histological/histomorphometric, birefringence, and molecular methods. The expression of iNOS had very low control conditions, whereas a significant increase is observed in healing sites of WT mice, where iNOS mRNA levels peak at 7d time point, followed by a relative decrease at 14d and 21d. Regarding bone healing, both WT and iNOS-KO groups showed the usual phases characterized by the presence of clots, granulation tissue development along the inflammatory cell infiltration, angiogenesis, proliferation of fibroblasts and extracellular matrix synthesis, bone neoformation, and remodeling. The overall micro-computed tomography and histomorphometric and birefringence analyses showed similar bone healing readouts when WT and iNOS-KO strains are compared. Likewise, Real-Time PCR array analysis shows an overall similar gene expression pattern (including bone formation, bone resorption, and inflammatory and immunological markers) in healing sites of WT and iNOS-KO mice. Moreover, molecular analysis shows that nNOS and eNOS were significantly upregulated in the iNOS-KO group, suggesting that other NOS isoforms could compensate the absence of iNOS. The absence of iNOS does not result in a significant modulation of bone healing readouts in iNOS-KO mice. The upregulation of nNOS and eNOS may compensate iNOS absence, explaining the similar bone healing outcome in WT and iNOS-KO strains.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing.

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Arginine Availability in Reamed Intramedullary Aspirate as Predictor of Outcome in Nonunion Healing.

Fracture healing and nonunion development are influenced by a range of biological factors. Adequate amino acid concentrations, especially arginine, are known to be important during normal bone healing. We hypothesize that bone arginine availability in autologous bone marrow grafting, when using the reamer-irrigator-aspirator (RIA) procedure, is a marker of bone healing capacity in patients treated for nonunion. Seventeen patients treated for atrophic long bone nonunion by autologous bone grafting by the RIA procedure were included and divided into two groups, successful treatment of nonunion and unsuccessful, and were compared with control patients after normal fracture healing. Reamed bone marrow aspirate from a site distant to the nonunion was obtained and the amino acids and enzymes relevant to arginine metabolism were measured. Arginine and ornithine concentrations were higher in patients with successful bone healing after RIA in comparison with unsuccessful healing. Ornithine concentrations and arginase-1 expression were lower in all nonunion patients compared to control patients, while citrulline concentrations were increased. Nitric oxide synthase 2 (Nos2) expression was significantly increased in all RIA-treated patients, and higher in patients with a successful outcome when compared with an unsuccessful outcome. The results indicate an influence of the arginine–nitric oxide metabolism in collected bone marrow, on the outcome of nonunion treatment, with indications for a prolonged inflammatory response in patients with unsuccessful bone grafting therapy. The determination of arginine concentrations and Nos2 expression could be used as a predictor for the successful treatment of autologous bone grafting in nonunion treatment.

Histologic Outcomes of the Use of Different Biomaterials for Socket Regeneration in Fresh Extraction Sockets: A Split-Mouth Randomized Clinical Trial.

To analyze the quality of bone regeneration in fresh sockets using four different materials at different time points. A split-mouth randomized clinical trial was designed to evaluate the histologic and histomorphometric characteristics of 82 fresh sockets from 30 patients. One socket per patient healed spontaneously (control), and at least one fresh socket was grafted with a material chosen randomly from a sealed envelope: plateletrich growth factor (PRGF; n = 20 sites), PRGF + autologous bone (n = 9 sockets), autologous bone (n = 10 sites), or PRGF + demineralized freeze-dried bone allograft (DFDBA; n = 13). Biopsy specimens were taken at different time points divided into three assessment groups: short duration (2 to 4 months), intermediate duration (5 to 6 months), and long duration (7 to 12 months). The histologic findings were assessed to quantify the trabeculae pattern, the degree of mineralization, and the quality of bone regeneration. A total of 26 patients with 73 sockets completed the study. Mineralization after a short duration was found to be significantly higher among sockets treated only with autologous bone (47.3% ± 3.6%) or with PRGF+autologous bone (45.1% ± 13.6%). During the intermediate time point, this difference was not observed; also, the control sites were found to have the highest amount of mineralization (37.7% ± 14.9%). After a long duration of wound healing, the PRGF+DFDBA group had the greatest percentage of mineralized tissue (54.7% ± 28.7%), which was significantly higher than the sites treated only with PRGF (30.0% ± 13.2%). From a histologic point of view, the use of autologous graft with or without PRGF seems to be the best strategy for socket regeneration within a short period of time (2 to 4 months). However, the application of PRGF alone inside fresh sockets may interfere with normal bone healing compared with control sites healed spontaneously.

Clodronate detection and effects on markers of bone resorption are prolonged following a single administration to horses.

Clodronate is a potent antiresorptive agent labelled for use in horses over 4 years of age, for the treatment of navicular syndrome. Concerns regarding the extra-label use of clodronate in equine athletes, such as racehorses, have been raised as inhibition of osteoclast activity by clodronate has been postulated to interfere with normal bone healing, which is imperative to the repair of microfractures. The paucity of data describing the long-term pharmacokinetics of clodronate and effects on biomarkers of bone resorption necessitates further study. (1) To determine clodronate concentrations in blood and urine over a 6-month period in horses undergoing treadmill exercise and (2) to assess the effects of clodronate on protein biomarkers of bone remodelling in this same group of horses. Randomised controlled experimental study. Seven exercised Thoroughbred horses received a single im administration of 1.8mg/kg clodronate and four horses received an equivalent volume of saline. Blood and urine samples were collected prior to, during and for 182 days post drug administration for drug concentration determination using liquid chromatography-tandem mass spectrometry, and determination of protein biomarker (CTX-1 and TRAcP5B) concentrations. Clodronate was detectable in blood for 14-175 days and for up to 175 days in urine. For some horses, concentrations were nondetectable at one time point but detectable at a subsequent time point. The terminal serum half-life ranged from 1.80 to 283.9 days. CTX-1 concentrations were significantly higher, relative to baseline, in both treated and control groups while concentrations of TRAcP5B were significantly lower in the treated group. Relatively small number of horses studied. Based on assessment of protein biomarkers, clodronate appears to influence osteoclasts at label doses. Furthermore, results of this study support racing regulations that preclude horses administered bisphosphonates for medical reasons, from racing for a prolonged period of time.

Self-expanding PMMA composite bone cement with sustained release of gentamicin sulfate and alendronate using water absorption pathways

Although drug-loaded polymethyl methacrylate (PMMA) bone cement had been widely used in the vertebroplasty and arthroplasty, the mismatch between the drug release cycle and clinical demand, as well as low drug release rate and single therapeutic effect restricted the use of PMMA bone cement as the drug carrier in clinical applications. In this study, poly(methyl methacrylate-acrylic acid)-alendronate [P(MMA-AA)-ALN] drug-loaded nanoparticles with anti-osteoporosis function were synthesized and introduced into the gentamicin sulfate (GS) loaded PMMA bone cement. The rapidly expandable bone cement with water absorption pathways was constructed by adjusting the particle size of P(MMA-AA)-ALN nanoparticles. More importantly, the sustained release of GS and ALN were creatively achieved by their migration through the water absorption pathways composed of P(MMA-AA)-ALN nanoparticles. The results showed that the cumulative release ratios of GS and ALN in the composites were up to 74.67 ± 1.02 % and 75.23 ± 1.96 %. Meanwhile, the release cycles of GS and ALN were extended to 4 weeks and 15 weeks, effectively preventing infection, and matching the normal bone healing cycle. In addition, the swelling and dual drug release bone cement (SDBC) displayed superior antibacterial activity and biocompatibility.

Histological Assessment of Injectable Macro-porous Calcium Phosphate Cement (CPC) Versus Autogenous Bone Graft on Healing of Osseous Defect (Experimental Animal Study)

Objective: The aim of this study is to evaluate histologically the healing potential of injectable macro-porous Calcium Phosphate Cement and autogenous bone. (Normal bone healing) on surgically induced bone defect on femur bone of rabbit. Materials and Methods: Twelve adult white male New Zealand rabbits were selected for this study. Rabbits were divided into two groups and the two groups according to a two evaluation periods divided into 2 subgroups. Rabbits were anesthetized with intramuscular anethesia, and two osseous defects had been created in the distal aspect of the femur bone.one of this defects injected by a grafting material (SI-HPMC CPC) and the other left empty as control (normal healing).Animal were sacrificed after two sacrifice dates and the femur bone excised for histological and statistical evaluation.esults: Rabbits from each group were sacrificed after 2 and 4 weeks. The femur bone containing the induced defect was dissected. Each femur bone was excised using hard tissue microtome. Each slice was then fixed in 10% neutral buffered formalin. The formalin-fixed bone samples were decalcified in 15% buffered formic acid solution and processed for routine histological examination using hematoxylin and eosin stain under light microscope.. Conclusion: According to our results in the present study, we can consider Si-HPMC CPC a viable alternative to the autogenous bone in the healing of osseous bone defects . In the present study, the new and simple method to prepare macroporous CPCs using Si-HPMC a foaming agent in connected syringe , result

Overcoming Nuclear Winter: The Cutting-edge Science of Bone Healing and Regeneration in Irradiated Fields.

Background:The incidence of cancer worldwide is expected to be more than 22 million annually by 2030. Approximately half of these patients will likely require radiation therapy. Although radiotherapy has been shown to improve disease control and increase survivorship, it also results in damage to adjacent healthy tissues, including the bone, which can lead to devastating skeletal complications, such as nonunion, pathologic fractures, and osteoradionecrosis. Pathologic fractures and osteoradionecrosis are ominous complications that can result in large bone and soft tissue defects requiring complex reconstruction. Current clinical management strategies for these conditions are suboptimal and dubious at best. The gold standard in treatment of severe radiation injury is free tissue transfer; however, this requires a large operation that is limited to select candidates.Methods:With the goal to expand current treatment options and to assuage the devastating sequelae of radiation injury on surrounding normal tissue, our laboratory has performed years of translational studies aimed at remediating bone healing and regeneration in irradiated fields. Three therapeutics (amifostine, deferoxamine, and adipose-derived stem cells) have demonstrated great promise in promoting healing and regeneration of irradiated bone.Results:Amifostine confers prophylactic protection, whereas deferoxamine and adipose-derived stem cells function to remediate postradiation associated injury.Conclusions:These prospective therapeutics exploit a mechanism attributed to increasing angiogenesis and ultimately function to protect or restore cellularity, normal cellular function, osteogenesis, and bone healing to nonirradiated metrics. These discoveries may offer innovative treatment alternatives to free tissue transfer with the added benefit of potentially preventing and treating osteoradionecrosis and pathologic fractures

A murine Staphylococcus aureus fracture-related infection model characterised by fracture non-union, staphylococcal abscess communities and myeloid-derived suppressor cells.

A fracture-related infection (FRI) is a serious complication that can occur after surgical fixation of bone fractures. Affected patients may encounter delayed healing and functional limitations. Although it is well established that Staphylococcus aureus (S. aureus) is the main causative pathogen of an FRI, the pathophysiology of an S. aureus-induced FRI is not well characterised over time. Therefore, an experimental study in mice comparing S. aureus-inoculated and non-inoculated groups was performed that particularly focused on staphylococcal abscess communities (SACs) and host cellular response. C57Bl/6N female mice received a double osteotomy of the femur, which was stabilised using a titanium 6-hole MouseFix locking plate and four screws. Animals were either S. aureus-inoculated or non-inoculated and euthanised between 1 and 28 d post-surgery. Histopathological evaluation showed normal bone healing for non-inoculated mice, whereas inoculated mice had no fracture consolidation and severe osteolysis. Within the bone marrow of inoculated mice, SACs were observed from 7 d, which increased in size and number over time. A fibrin pseudocapsule enclosed the SACs, which were surrounded by many Ly6G+ neutrophils with some Ly6C+ monocytes and F4/80+ macrophages, the majority of which were viable. The abscesses were encapsulated by fibrin(ogen), collagen and myofibroblasts, with regulatory T cells and M2 macrophages at the periphery. Only bone marrow monocytes and neutrophils of inoculated mice displayed functional suppression of T cells, indicative of myeloid-derived suppressor cells. The present study revealed that an FRI in mice is persistent over time and associated with osteolysis, SAC formation and an immunosuppressive environment.

Plant-derived soybean peroxidase stimulates osteoblast collagen biosynthesis, matrix mineralization, and accelerates bone regeneration in a sheep model

Bone defects arising from fractures or disease represent a significant problem for surgeons to manage and are a substantial economic burden on the healthcare economy. Recent advances in the development of biomaterial substitutes provides an attractive alternative to the current “gold standard” autologous bone grafting. Despite on-going research, we are yet to identify cost effective biocompatible, osteo-inductive factors that stimulate controlled, accelerated bone regeneration.We have recently reported that enzymes with peroxidase activity possess previously unrecognised roles in extracellular matrix biosynthesis, angiogenesis and osteoclastogenesis, which are essential processes in bone remodelling and repair. Here, we report for the first time, that plant-derived soybean peroxidase (SBP) possesses pro-osteogenic ability by promoting collagen I biosynthesis and matrix mineralization of human osteoblasts in vitro. Mechanistically, SBP regulates osteogenic genes responsible for inflammation, extracellular matrix remodelling and ossification, which are necessary for normal bone healing. Furthermore, SBP was shown to have osteo-inductive properties, that when combined with commercially available biphasic calcium phosphate (BCP) granules can accelerate bone repair in a critical size long bone defect ovine model. Micro-CT analysis showed that SBP when combined with commercially available biphasic calcium phosphate (BCP) granules significantly increased bone formation within the defects as early as 4 weeks compared to BCP alone. Histomorphometric assessment demonstrated accelerated bone formation prominent at the defect margins and surrounding individual BCP granules, with evidence of intramembranous ossification. These results highlight the capacity of SBP to be an effective regulator of osteoblastic function and may be beneficial as a new and cost effective osteo-inductive agent to accelerate repair of large bone defects.

Synthesis, Structural Characterization, Degradation Rate, and Biocompatibility of Magnesium-Carbonate Apatite (Mg-Co3Ap) Composite and Its Potential as Biodegradable Orthopaedic Implant Base Material

Suitable biomechanical properties with a degradation rate parallel to normal bone healing time are vital characteristics for biodegradable implant material in orthopaedics. Magnesium (Mg) is a natural micronutrient as well as biodegradable metal with biomechanical characteristics close to that of the human bone, while carbonate apatite (CO3Ap) is a biological apatite with good osteoconductivity which allows bone healing without forming fibrotic tissue. We fabricated a Mg-CO3Ap composite with various content ratios by powder metallurgy, various milling times (3, 5, and 7 hours) at 200 RPM, warm compaction at 300°C and pressure of 265 MPa, sintering at 550°C, holding time of 1 hour, heating rate of 5°C/minutes, and room atmosphere cooling. Specimens were successfully created and had a density comparable to that of the human bone (1.95-2.13 g/cm3). Good biocompatibility was found on Mg-10% CO3Ap composite (66.67% of viable cells). Nevertheless, its biomechanical properties and corrosion resistance were inferior to the human bone. Additionally, the materials of the composites make the surrounding environment alkaline. Interparticle consolidation and grain size were dissatisfactory due to microstructural pores presumably formed by the Mg(OH)2 layer and oxidation process during sintering. However, alkaline condition caused by the material corrosion by-product might be beneficial for bone healing and wound healing process. Modifications on fabrication parameters are needed to improve interparticle consolidation, refine grain size, improve biomechanical strength, reduce corrosion products, and improve the degradation rate.

Whole Genome Gene Expression: Histologic and Immunohistologic Study of Grafted Bone Using Allograft and Xenograft.

The aim of this study was to explore the influence of different bone grafts, demineralized freeze-dried bone allograft (DFDBA, OraGraft), and deproteinized bovine bone mineral (DBBM, Bio-Oss) implanted in mouse calvaria defects on gene expression. Male C57BL/6MLac mice were separated into three groups as follows: group 1-defect without graft as control, group 2-DFDBA, and group 3-DBBM. Affymetrix DNA microarrays were used to characterize gene expression in bone after 3 months of graft healing. Differential expression of designated genes discovered by microarray analysis was confirmed using real-time polymerase chain reaction (PCR) and immunohistochemistry. Compared with normal bone healing, 355 and 1,108 coding genes of bone grafted with DFDBA were upregulated and downregulated, respectively. The upregulated genes were mainly involved in chemokine signaling, macrophage activity, osteoclast activity, cytokine expression, T-cell receptor signaling, apoptosis, and MAPK signaling. The downregulated genes were predominantly involved in calcium regulation in cardiac cells, chemokine signaling, MAPK signaling, and adipogenesis. A total of 306 and 817 coding genes of bone grafted with DBBM were upregulated and downregulated, respectively. The upregulated genes were mainly involved in osteoclast activity, chemokine signaling, B cell receptor signaling, macrophage activity, and signaling of T-cell receptor, MAPK, IL-5, and IL-1. The downregulated genes were predominantly involved in calcium regulation in the cardiac cell and osteoclast activity. Real-time PCR revealed that the DFDBA and DBBM groups showed a higher mRNA level of MMP12, Bcl2A1, S100A4, and Postn compared with the control (P < .05). Histology showed that, compared with the control, the volume of new bone was higher in both types of bone grafts. Immunohistochemistry using an MMP12 antibody confirmed the microarray results because the MMP12 immunoreactivity intensified, and a positive expression of MMP12 increased significantly in the DFDBA and DBBM groups. Both DFDBA and DBBM had a gene expression network involved in new bone formation, which coincided with an increased expression of MMP-12 and osteoclast activity. Both types of graft materials appeared to connect with genes that stimulate bone remodeling at 3 months of bone grafting.

Both Human Hematoma Punctured from Pelvic Fractures and Serum Increase Muscle Resident Stem Cells Response to BMP9: A Multivariate Statistical Approach.

Hematoma and skeletal muscles play a crucial role in bone fracture healing. The muscle resident mesenchymal stromal cells (mrSCs) can promote bone formation by differentiating into osteoblasts upon treatment by bone morphogenetic proteins (BMP), such as BMP9. However, the influence of hematoma fracture extracts (Hema) on human mrSC (hmrSC) response to BMP9 is still unknown. We therefore determined the influence of Hema, human healthy serum (HH), and fetal bovine serum (FBS, control) on BMP9-induced osteoblast commitment of hmrSC by measuring alkaline phosphatase activity. Multiplex assays of 90 cytokines were performed to characterize HH and Hema composition and allow their classification by a multivariate statistical approach depending on their expression levels. We confirmed that BMP9 had a greater effect on osteoblastic differentiation of hmrSCs than BMP2 in presence of FBS. The hmrSCs response to BMP9 was enhanced by both Hema and HH, even though several cytokines were upregulated (IL-6, IL-8, MCP-1, VEGF-A and osteopontin), downregulated (BMP9, PDGF) or similar (TNF-alpha) in Hema compared with HH. Thus, hematoma may potentiate BMP9-induced osteogenic differentiation of hmrSCs during bone fracture healing. The multivariate statistical analyses will help to identify the cytokines involved in such phenomenon leading to normal or pathological bone healing.

The effect of low-intensity pulsed ultrasound on rib fracture: An experimental study.

In this study, we aimed to investigate the effects of lowintensity pulsed ultrasound on rib fracture healing in a rat model. A total of 72 male Wistar-Albino rats were randomly divided into three equal groups. To induce a rib fracture, right thoracotomy was performed under general anesthesia and a 0.5-cm segment was removed from the fourth and fifth ribs. After 24 h of surgery, low-intensity pulsed ultrasound was implemented according to the groups. Group 1 served as the control group for the observation of normal bone healing. Low-intensity pulsed ultrasound was applied at a dose of 20% (2 msn pulse-8 msn pause) 100 mW/cm2 and 50% (5 msn pulse-5 msn pause) 200 mW/cm2 for six min, respectively in Group 2 and Group 3. All subjects were followed for six weeks. Eight animals from each group were sacrificed at two, four, and six weeks for further assessment. Histological alterations in the bone were examined. Although there was no statistically significant difference in osteoblasts, osteoclasts, new bone formation, and lymphocyte count among the groups, histological consolidation was significantly increased by low-intensity pulsed ultrasound. While low-intensity pulsed ultrasound induced osteoblastic, osteoclastic, and new bone formation, it inhibited lymphocyte infiltration. Low-intensity pulsed ultrasound, either at low or high doses, induced the histological consolidation of rib fractures and inhibited lymphocyte infiltration. This effect was more prominent in the long-term and at higher dose with increased daily and total administration time. We, therefore, believe that accelerating the natural healing process in patients with rib fractures would enable to treat more effectively in short-term.