Objectives. Platelet-rich plasma (PRP) is being used increasingly often in the clinical setting to treat tendon-related pathologies. Yet the optimal PRP preparations to promote tendon healing in different patient populations are poorly defined. Here, we sought to determine whether increasing the concentration of platelet-derived proteins within a derivative of PRP, platelet lysate (PL), enhances tenocyte proliferation and
Objectives. Cellular movement and relocalisation are important for many physiologic properties. Local mesenchymal stem cells (MSCs) from injured tissues and circulating MSCs aid in fracture healing. Cytokines and chemokines such as Stromal cell-derived factor 1(SDF-1) and its receptor chemokine receptor type 4 (CXCR4) play important roles in maintaining mobilisation, trafficking and homing of stem cells from bone marrow to the site of injury. We investigated the differences in
Background. Osteoporosis and bone fractures lead to immobility, chronic pain and high patient care costs. Mesenchymal stem cells (MSCs) from postmenopausal women have a slower growth rate and osteogenic differentiation ability causing lower bone density and reduced fracture healing capacity compared to MSCs from premenopausal women. Cellular movement and relocalisation are necessary for many physiologic properties. Local MSCs from injured tissues and circulating MSCs are involved in fracture healing. Cytokines and chemokines such as SDF-1 and its receptor CXCR4 play important roles in maintaining mobilisation, trafficking and homing of stem cells from bone marrow to the site of injury. This study investigated the effect of CXCR4 over-expression on the
Introduction.
The current treatment for osteoporosis such as bisphosphonates inhibits the catabolic activity of osteoclasts and subsequent bone resorption, but does not increase bone formation. There is therefore interest in using anabolic factors such as stem cells to augment fracture repair. The poor bone formation in postmenopausal women could be due to poor retention and function of Mesenchymal stem cells (MSCs) resulting into delayed unions. Another factor associated with fracture healing is the retention and
Studies on the
There is increasing interest in using anabolic factors such as stem cells to augment fragility fracture repair. One of the factors associated with fracture healing is the retention and
Studies using roentgen stereophotogrammetric analysis (RSA) have shown that the femoral components of cemented total hip replacements (THR) migrate distally relative to the bone, but it is not clear whether this occurs at the cement-implant or the cement-bone interface or within the cement mantle. Our aim was to determine where this
Summary Statement. In articular cartilage defects, chemokines are upregulated and potentially induce the
Intermittent parathyroid hormone 1–34 (teriparatide) is the N-fragment terminal of the intact hormone, currently in clinical use to treat osteoporosis. Unlike anti-catabolic agents such as bisphosphonates, PTH 1–34 not only affects the osteoclast, but also up regulates bone formation via both modelling and remodelling mechanisms. The actions of iPTH on mesenchymal stem cell differentiation (MSCs) may underpin a further method in the treatment of osteoporosis specifically, and for fracture healing in general. Stem cells from older female osteoporotic animals have reduced activity and poorer osteogenic potential; additionally, their
Intermittent parathyroid hormone (iPTH 1–34) increases bone formation via modelling and remodelling mechanisms and as such is used to treat osteoporosis. The actions of iPTH on mesenchymal stem cell (MSCs) may underpin a further treatment option. We isolated bone marrow derived MSCs from young (WT) and ovarectomized senile (OVX) rats, investigating the effect of intermittent and continuous PTH administration on
Prosthesis
Introduction. Primary mechanical stability is important with uncemented THR because early
Malalignment is often postulated as the main reason for the high failure rate of total ankle replacements (TARs). Only a few studies have been performed to correlate radiographic TAR malalignment to the clinical outcome, but no consistent trends between TAR alignment parameters and the clinical outcome were found. No standard TAR alignment measurement method is present, so reliable comparison between studies is difficult. Standardizing TAR alignment measurements and increasing measurable parameters on radiographs in the clinic might lead to a better insight into the correlation between malalignment and the clinical outcome. This study aims to develop and validate a tool to semi-automatic measure TAR alignment, and to improve alignment measurement on radiographs in the clinic. A tool to semi-automatically measure TAR alignment on anteroposterior and lateral radiographs was developed and used by two observers to measure TAR alignment parameters of ten patients. The Intraclass Coefficient (ICC) was calculated and accuracy was compared to the manual measurement method commonly used in the clinic. The tool showed an accuracy of 76% compared to 71% for the method used during follow-up in the clinic. ICC values were 0.94 (p<0.01) and higher for both inter-and intra-observer reliability. The tool presents an accurate, consistent, and reliable method to measure TAR alignment parameters. Three-dimensional alignment parameters are obtained from two-dimensional radiographs, and as the tool can be applied to any TAR design, it offers a valuable addition in the clinic and for research purposes.
We have studied the beneficial effects of a hydroxyapatite (HA) coating on the prevention of the
CAR (CARSKNKDC) is a systemically administered wound-homing peptide that specifically recognizes angiogenic blood vessels and extravasates into sites of injury. CAR peptide requires heparan sulfate proteoglycans (HSPGs) for its cell penetrating activity. Syndecan-4 (SDC4) is a HSPG and binding to it triggers the wound re-epithelialization process. We have discovered that CAR peptide has the inherent ability to promote wound healing; wounds close and re-epithelialize significantly faster in CAR treated mice than in control groups (PBS and mutant peptide, i.e. mCAR injections). To delineate the molecular mechanism by which CAR accelerates wound healing, we focused on the requirement of HSPG binding for CAR peptide function. We demonstrate that CAR peptide endocytosis and its stimulation of keratinocyte cell
Our aim was to determine whether tantalum markers improved the accuracy and/or precision of methods for the measurement of
Summary Statement. We analysed impaction bone grafting used together with cemented or uncemented fixation in acetabular revision surgery. The overall risk for re-revision did not differ between the cemented and uncemented group. However, aseptic loosening was more common in the cemented group. Background. Several surgical techniques address bone defects in cup revision surgery. Bone impaction grafting, introduced more than thirty years ago, is a biologically and mechanically appealing method. The primary aim of this study was to evaluate the effect of bone impaction grafting when used with uncemented and cemented fixation in cup revision surgery. Uncemented cups resting on more than 50% host bone were used as controls. Patient and Methods. Cup fixation was studied in ninety hips (eighty-two patients), revised due to loosening between 1993 and 1997. There were fifty-three isolated cup and thirty-seven total revisions. Patients were followed for thirteen years using conventional radiography, radiostereometry (RSA), Harris Hip score and a pain questionnaire. Peroperatively the surgeon assessed the acetabular bone bed vitality. In hips where the cup was judged to rest on > 50% vital bone (group I, n=43), an uncemented cup was used. If the cup was resting on ≤ 50% living bone, uncemented (group IIa, n=21,) or cemented (group IIb, n=26) technique was chosen, according to the surgeon's preference. The mean age of patients at index revision was 61±12 years, 56% were females. The most common index diagnosis was primary osteoarthritis (n=45) followed by rheumatoid arthritis (n=10). Results. At thirteen years, acetabular component failure had necessitated a second revision in 6/7/8 hips in Groups I/IIa/IIb respectively. These re-revisions were performed 1–10 (mean 7.1) years after index revision. Moreover four cup / liner revisions were performed in hips with femoral loosening, not allowing further RSA measurements. These twenty-five hips were followed until re-revision. Deceased patients (n=21) and patients with deteriorating medical condition, not able to attend the follow-up (n=7), were censored in the survival statistics. Aseptic loosening was the most common reason of re-revision. However, in the uncemented groups (I/IIa), four cups were re-revised due to liner wear, osteolysis or instability. In the total study population, and up to two years, the median proximal
Tissue repair is believed to rely on tissue-resident progenitor cell populations proliferating, migrating, and undergoing differentiation at the site of injury. During these processes, the crosstalk between mesenchymal stromal/stem cells (MSCs) and macrophages has been shown to play a pivotal role. However, the influence of extracellular matrix (ECM) remodelling in this crosstalk, remains elusive. Human MSCs cultured on tissue culture plastic (TCP) and encased within fibrin in vitro were treated with/without TNFα and IFNγ. Human monocytes were cocultured with untreated/pretreated MSCs on TCP or within fibrin. After seven days, the conditioned media (CM) were collected. Human chondrocytes were exposed to CM in a
Abstract. Objectives. Tissue repair is believed to rely on tissue-resident progenitor cell populations proliferating, migrating, and undergoing differentiation at the site of injury. During these processes, the crosstalk between mesenchymal stromal/stem cells (MSCs) and macrophages has been shown to play a pivotal role. However, the influence of extracellular matrix (ECM) remodelling in this crosstalk, remains elusive. Methods. Human MSCs cultured on tissue culture plastic (TCP) and encased within fibrin in vitro were treated with/without TNFα and IFNγ. Human monocytes were cocultured with untreated/pretreated MSCs on TCP or within fibrin. After seven days, the conditioned media (CM) were collected. Human chondrocytes were exposed to CM in a