Volume and density of
Volume and density of
Aims. Impaired fracture repair in patients with type 2 diabetes mellitus (T2DM) is not fully understood. In this study, we aimed to characterize the local changes in gene expression (GE) associated with diabetic fracture. We used an unbiased approach to compare GE in the
Infections regularly complicate orthopaedic procedures loosing implant stability and impairing bone union. Nevertheless, the question whether infection is caused by pathogens transposed intraoperatively, infiltrating the implant with blood stream or lymph, or dwelling in clinically healthy tissues, remains unanswered. The AIM of our study was to validate the hypothesis that pathogens may residue deep tissue. Material and Methods: Skin, subcutaneous fat, muscle and
Aims: The use of vitamin K was proposed in the treatment of osteoporosis. Some experimental studies suggested that vitamin K might promote mesenchymal stem cells (MSCs) differentiation into osteoblasts progenitors and inhibit osteoclasts formation. In the present study we analysed the effects of vitamin K at different concentrations on human mesenchymal stem cells derived from
The Dkk3-derived cells represent a branch of the periosteal mesenchymal lineage that produces fibrocartilage as well as regenerating the periosteal structures. Mesenchymal progenitor cells are capable of generating a wide variety of mature cells that constitute the connective tissue system. Our Laboratory has been developing SMAA GFP reporter mice to prove to be an effective tool for identifying these cells prior to the expression of markers of differentiation characteristic of bone, fat, muscular blood vessels or fibrocartilage. Dkk3 was chosen as a candidate reporter because microarray of SMAA-sorted cells culture indicated high expression of this non-canonical anti-Wnt factor, which was not anticipated in a culture with strong osteogenic potential.Summary Statement
Introduction
Secondary fracture healing processes are strongly influenced by interfragmentary motion. Shear movement is assumed to be more critical than axial movement, however experimental results are controversial. Numerical fracture healing models allow to simulate the fracture healing process with variation of single input parameters and under comparable normalized mechanical conditions. Therefore, a direct comparison of different in vivo scenarios is possible. The aim of this study was to simulate fracture healing under several axial and shear movement scenarios and compare their respective time to heal. We hypothesize that shear movement is always more critical than axial loading. For the presented study, we used a corroborated numerical model for fracture healing in sheep. Numerous variations of the movement amplitude, the fracture gap size and the musculoskeletal loads were simulated for comparable axial compressive and shear load cases. In all simulated cases, axial compressive load had less inhibitory influences on the healing process than shear load. Therefore, shear loading is more critical for the fracture healing outcome in general. Thus, our findings suggest osteosynthesis implants to be optimized to limit shear movements under musculoskeletal loading.
Virtual mechanical testing is a method for measuring bone healing using finite element models built from computed tomography (CT) scans. Previously, we validated a dual-zone material model for ovine
Integrin α2β1 is one of the major transmembrane receptors for fibrillary collagen. In native bone we could show that the absence of this protein led to a protective effect against age-related osteoporosis. The objective of this study was to elucidate the effects of integrin α2β1 deficiency on fracture repair and its underlying mechanisms. Standardised femoral fractures were stabilised by an intramedullary nail in 12 week old female C57Bl/6J mice (wild type and integrin α2. -/-. ). After 7, 14 and 28 days mice were sacrificed. Dissected femura were subjected to µCT and histological analyses. To evaluate the biomechanical properties, 28-day-healed femura were tested in a torsional testing device. Masson goldner staining, Alizarin blue, IHC and IF staining were performed on paraffin slices. Blood serum of the animals were measured by ELISA for BMP-2. Primary osteoblasts were analysed by in/on-cell western technology and qRT-PCR. Integrin α2β1 deficient animals showed earlier transition from cartilaginous callus to mineralized
Mice are increasingly used for fracture healing research because of the possibility to use transgenic animals to conduct research on the molecular level. Mice from both sexes can be used, however, there is no consensus in the literature if fracture healing differs between female and male mice. Therefore, the aim of the present study was to analyze the similarities and differences in endochondral fracture healing between female and male C57BL/6J mice, since this mouse strain is mainly used in bone research. For that purpose, 12-weeks-old female and male mice received a standardized femur midshaft osteotomy stabilized by an external fixator. Mice were euthanized 10 and 21 days after fracture and bone regeneration was analyzed by biomechanical testing, µCT analysis, histology, immunohistochemistry and gene expression analysis. At day 21, male mice displayed a significantly larger
Objectives. Ubiquitin E3 ligase-mediated protein degradation regulates osteoblast function. Itch, an E3 ligase, affects numerous cell functions by regulating ubiquitination and proteasomal degradation of related proteins. However, the Itch-related cellular and molecular mechanisms by which osteoblast differentiation and function are elevated during bone fracture repair are as yet unknown. Methods. We examined the expression levels of E3 ligases and NF-κB members in callus samples during bone fracture repair by quantitative polymerase chain reaction (qPCR) and the total amount of ubiquitinated proteins by Western blot analysis in wild-type (WT) mice. The expression levels of osteoblast-associated genes in
Secondary bone healing is impacted by the extent of interfragmentary motion at the fracture site. It provides mechanical stimulus that is required for the formation of
Cyclooxygenase-2 (COX-2) activity is necessary for fracture healing to proceed normally. In most cell types, COX-2 is inductively expressed and acts in a coordinated pathway to produce prostaglandins, which affect many physiological processes including inflammation. In the
Summary Statement. This study demonstrated that Sclerostin monoclonal antibody (Scl-Ab) enhanced bone healing in the rat osteotomy model. Scl-Ab increased callus size, callus bone volume fraction, rate of callus bone formation and
Introduction. The fracture healing outcome is often evaluated via ex vivo testing of the
Background and Hypothesis: High-energy fractures associated with severe soft tissue injury have a significant incidence of delayed or non-union. The soft tissue envelope may adversely contribute to the healing of a fracture, not only in stripping of the periosteal blood supply, development of compartment syndrome or tissue interposition between the bone ends but also in its ability to generate an intense acute inflammatory response. Inflammation is the initiator of healing; in clinical scenarios of impaired inflammation (immune deficiency, NSAIDs, corticosteroids) healing is delayed; interestingly, in injury with excess inflammation (CVA, MI) healing is also delayed. Would the inflammatory response following high-energy fractures contribute beneficially or adversely to the healing of the underlying fracture? Using an in-house murine femoral fracture model which reliably demonstrated features of delayed fracture healing when associated with a severe overlying muscle crush injury we proposed these hypotheses:. That
Fracture healing is an issue that has not yet been fully elucidated. It is generally accepted in the literature that head trauma accelerates fracture healing and causes higher volume callus tissue. Recent studies have examined the relationship between head trauma and fracture healing more molecularly. Based on this research; the aim of this study is to show the effect of head trauma on fracture healing radiologically and histologically and to investigate the relationship between serum β-Catenin level and fracture healing with the experiment we performed on rats. A total of 36 Wistar Albino female rats with a mean age of 24 weeks were included in the study with the permission of Mersin University Animal Experiments Local Ethics Committee. Six rats in the first group were not traumatized and their blood samples were collected on the day of the experiment started, end of the third week and end of the sixth week. In the second group, only head trauma was performed and blood samples were collected at the end of the third and sixth weeks. In the third group, only open femoral fracture model was applied, blood samples were collected at the third and sixth weeks and AP and Lateral radiographs of the fractured femurs were taken. After sacrification, femurs were dissected from the surrounding soft tissues and subjected to histological examination. In the fourth group, both head trauma and open femur fracture model were applied, blood samples were collected at the end of third and sixth weeks and AP and Lateral radiographs of the fractured femurs were taken. After sacrification, femurs were dissected from the surrounding soft tissues and subjected to histological examination. The expression level of β-Catenin was measured by PCR from all blood samples. Direct radiographs of the third and fourth groups at 3 and 6 weeks were evaluated by two orthopedists according to Rust and Lane & Sandhu scoring system. The histomorphometric examination was performed by evaluating the Huo scoring and the ratio of
Aims: Cell enlargement or hypertrophy is an intermediate transitional process in the transformation of Òsoft callusÒ into bone. The purpose of this study was to determine whether it is caused by an osmotic phenomenon. Following bone fracture, there is a local increase in tissue ßuid due to inßammation and neovascularisation. According to the osmosis principle, cells bathed in excess tissue ßuid swell. Methods: The specimens examined were 1 and 2-week old closed fractures of the right tibia of 12 NZW rabbits created by a drop tower technique. The specimens were prepared for routine histology. Thin sections were stained for haematoxylin and eosin and examined with the light microscope. Results: Cell enlargement and cell rupture were observed principally in the vicinity of the blood vessels. There was a hierarchy of cell sizes with the larger cells close to the blood vessels and the smaller ones further away from the vessels. Conclusions: According to these þndings, the
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
Previously, we reported impaired biomechanical bone properties and inferior bone matrix quality in tachykinin1 (Tac1)-deficient mice lacking the sensory neuropeptide substance P (SP). Additionally,