Aims. To investigate whether idiopathic osteonecrosis of the femoral head (ONFH) is related to impaired
Aims. Bone regeneration during treatment of staphylococcal bone infection is challenging due to the ability of Staphylococcus aureus to invade and persist within
Osteoarthritis (OA) is mainly caused by ageing, strain, trauma, and congenital joint abnormalities, resulting in articular cartilage degeneration. During the pathogenesis of OA, the changes in subchondral bone (SB) are not only secondary manifestations of OA, but also an active part of the disease, and are closely associated with the severity of OA. In different stages of OA, there were microstructural changes in SB. Osteocytes,
To determine whether spinal facet
Introduction and Objective. Osteonecrosis of the femoral head (ONFH) is an evolving and disabling condition that often leads to subchondral collapse in late stages. It is the underlying diagnosis for approximately 3%–12% of total hip arthroplasties (THAs) and the most frequent aetiology for young patients undergoing THA. To date, the pathophysiological mechanisms underlying ONFH remain poorly understood. In this study, we investigated whether ONFH without an obvious etiological factor is related to impaired
Aims. Accumulated evidence indicates that local cell origins may ingrain differences in the phenotypic activity of human
Fractures and related complications are a common challenge in the field of skeletal tissue engineering. Vitamin D and calcium are the only broadly available medications for fracture healing, while zinc has been recognized as a nutritional supplement for healthy bones. Here, we aimed to use polaprezinc, an anti-ulcer drug and a chelate form of zinc and L-carnosine, as a supplement for fracture healing. Polaprezinc induced upregulation of osteogenesis-related genes and enhanced the osteogenic potential of human bone marrow-derived mesenchymal stem cells and osteoclast differentiation potential of mouse bone marrow-derived monocytes. In mouse experimental models with bone fractures, oral administration of polaprezinc accelerated fracture healing and maintained a high number of both
Objectives. Osteoporosis is a metabolic disease resulting in progressive loss of bone mass as measured by bone mineral density (BMD). Physical exercise has a positive effect on increasing or maintaining BMD in postmenopausal women. The contribution of exercise to the regulation of osteogenesis in
Total hip arthroplasty (THA) outcome in patients with osteonecrosis of the femoral head ONFH) are excellent, however, there is controversy when compared with those in patients with osteoarthritis (OA). Reduced mineralization capacity of
Obesity is correlated with the development of osteoporotic diseases. Gut microbiota-derived metabolite trimethylamine-n-oxide (TMAO) accelerates obesity-mediated tissue deterioration. This study was aimed to investigate what role TMAO may play in osteoporosis development during obesity. Mice were fed with high-fat diet (HFD; 60 kcal% fat) or chow diet (CD; 10 kcal% fat) or 0.2% TMAO in drinking water for 6 months. Body adiposis and bone microstructure were investigated using μCT imaging. Gut microbiome and serum metabolome were characterized using 16S rRNA sequencing and liquid chromatography-tandem mass spectrometry. Osteogenic differentiation of bone-marrow mesenchymal cells was quantified using RT-PCR and von Kossa staining. Cellular senescence was evaluated by key senescence markers p16, p21, p53, and senescence association β-galactosidase staining. HFD-fed mice developed hyperglycemia, body adiposis and osteoporosis signs, including low bone mineral density, sparse trabecular microarchitecture, and decreased biomechanical strength. HFD consumption induced gut microbiota dysbiosis, which revealed a high Firmicutes/Bacteroidetes ratio and decreased α-diversity and abundances of beneficial microorganisms Akkermansiaceae, Lactobacillaceae, and Bifidobacteriaceae. Serum metabolome uncovered increased serum L-carnitine and TMAO levels in HFD-fed mice. Of note, transplantation of fecal microbiota from CD-fed mice compromised HFD consumption-induced TMAO overproduction and attenuated loss in bone mass, trabecular microstructure, and bone formation rate. TMAO treatment inhibited trabecular and cortical bone mass and biomechanical characteristics; and repressed osteogenic differentiation capacity of bone-marrow mesenchymal cells. Mechanistically, TMAO accelerated mitochondrial dysfunction and senescence program, interrupted mineralized matrix production in
Objectives. Enhanced micromotions between the implant and surrounding bone can impair osseointegration, resulting in fibrous encapsulation and aseptic loosening of the implant. Since the effect of micromotions on human bone cells is sparsely investigated, an in vitro system, which allows application of micromotions on bone cells and subsequent investigation of bone cell activity, was developed. Methods. Micromotions ranging from 25 µm to 100 µm were applied as sine or triangle signal with 1 Hz frequency to human
In an attempt to increase the life of cementless prostheses, an hydroxyapatite-coated implant which releases a bisphosphonate has been suggested as a drug-delivery system. Our in vitro study was designed to determine the maximum dose to which
Objectives. Osteoporosis is a systemic bone metabolic disease, which often occurs among the elderly. Angelica polysaccharide (AP) is the main component of angelica sinensis, and is widely used for treating various diseases. However, the effects of AP on osteoporosis have not been investigated. This study aimed to uncover the functions of AP in mesenchymal stem cell (MSC) proliferation and
Aims. This study aimed to examine the effects of tumour necrosis factor-alpha (TNF-α) on
Osteoporosis accounts for a leading cause of degenerative skeletal disease in the elderly.
Objectives. Oxidative stress plays a major role in the onset and progression of involutional osteoporosis. However, classical antioxidants fail to restore
Peri-prosthetic osteolysis and subsequent aseptic
loosening is the most common reason for revising total hip replacements.
Wear particles originating from the prosthetic components interact
with multiple cell types in the peri-prosthetic region resulting
in an inflammatory process that ultimately leads to peri-prosthetic
bone loss. These cells include macrophages, osteoclasts, osteoblasts
and fibroblasts. The majority of research in peri-prosthetic osteolysis
has concentrated on the role played by osteoclasts and macrophages.
The purpose of this review is to assess the role of the osteoblast
in peri-prosthetic osteolysis. In peri-prosthetic osteolysis, wear particles may affect osteoblasts
and contribute to the osteolytic process by two mechanisms. First,
particles and metallic ions have been shown to inhibit the osteoblast
in terms of its ability to secrete mineralised bone matrix, by reducing
calcium deposition, alkaline phosphatase activity and its ability
to proliferate. Secondly, particles and metallic ions have been
shown to stimulate
Objectives. Ubiquitin E3 ligase-mediated protein degradation regulates
Paget’s disease of bone is a common disorder characterised by focal areas of increased bone resorption coupled to increased and disorganised bone formation. Pagetic osteoclasts have been studied extensively, however, due to the integral cross-talk between osteoclasts and
Aseptic loosening is the single most important long-term complication of total joint arthroplasty. Wear debris induced inflammation stimulates osteoclastic resorption of bone. Cellular mechanisms involved in
The pathogenesis of falling bone mineral density (BMD) as a universal feature of advancing age is poorly understood. 1. Frequently culminating in the development of osteoporosis, the process is attributable to more than 500,000 fragility fractures occurring every year in the UK Such injuries are associated with great levels of morbidity, mortality and a £3.5 billion cost to the healthcare economy. 2. . With age, humans are known to accumulate somatic mitochondrial DNA (mtDNA) mutations in mitotic and post mitotic tissue, and stem cell precursors. 3. Compelling evidence in recent years, particularly that provided by animal models suggests that these mutations are intrinsic to the ageing process. 4–6. We provide evidence for the first time that mitochondrial dysfunction contributes significantly to the failure of bone homeostasis and falling BMD. We have utilised a mouse model that accumulates mtDNA mutations at 3–5 times the rate of normal mice, consequently ageing and developing osteoporosis prematurely. 7. , to clearly demonstrate that
Introduction Efficient control of
Cell micro-environment and biochemical, physical and mechanical signals coming from their micro-environment orientate specific functions of cells. In this study, we prepared novel hydrophilic and hydrophobic amino acids conjugated self-assembled molecules (AA-SAMs) modified Polydimethylsiloxane (PDMS) in order to observe the effect of hydropathy on
The T-lymphocyte secreted pro-inflammatory cytokine, interleukin-17F (IL-17F), was found to be a key mediator in the cellular response of the immune system in the early phase of fracture repair but its intracellular signaling processes are currently not known in
Objectives. Effects of insulin-like growth factor 1 (IGF1), fibroblast growth
factor 2 (FGF2) and bone morphogenetic protein 2 (BMP2) on the expression
of genes involved in the proliferation and differentiation of osteoblasts
in culture were analysed. The best sequence of growth factor addition
that induces expansion of cells before their differentiation was
sought. Methods. Primary human
Introduction: MEPE was identified in patients with tumors and oncogenic hypophosphatemic osteomalacia (OHO), and therefore thought to inhibit
Background. Uncemented implants are an important part of the arthroplasty armamentarium. Risk of aseptic loosening and failure of these components is related to initial osseointegration - the formation of a seamless bone-implant interface without interposition of fibrous tissue. Aim. Modification of the surface properties of titanium alloy, to enhance suitability for early osseointegration. Methods and Results. Samples of Ti6Al4V were prepared with different surface finishes: machined; polished with grit papers to a mirror finish or treated in an electrochemical cell with sulphuric acid/methanol electrolyte using 3, 5 or 9V for 60, 120 or 180 seconds . Electrochemical modification produced average roughness (Ra) values, which differed significantly between the 3 different voltages applied (p<0.05) with those treated at 3V being the roughest and those at 9V the smoothest. Rat
Several electrical fields are known to be present in bone tissue as originally described by Fukada and Yasuda in the year 1957. Intrinsic voltages can derive from bone deformation and reversely lead to mechanical modifications, called the piezoelectric effect. This effect is used in the clinic for the treatment of bone defects by applying electric and magnetic stimulation directly to the bone supplied with an implant such as the electroinductive screw system. Through this system a sinusoidal alternating voltage with a maximum of 700 mV can be applied which leads to an electric field of 5–70 V/m in the surrounding bone. This approach is established for bone healing therapies. Despite the established clinical application of electrical stimulation in bone, the fundamental processes acting during this stimulation are still poorly understood. A better understanding of the influence of electric fields on cells involved in bone formation is important to improve therapy and clinical success. To study the impact of electrical fields on bone cells in vitro, Ti6Al4V electrodes were designed according to the pattern of the ASNIS III s screw for a 6-well system. Osteoblasts were seeded on collagen coated coverslip and placed centred on the bottom of each well. During four weeks the cells were stimulated 3×45 min/d and metabolic and alkaline phosphatase (ALP) activity as well as gene expression of cells were analysed. Furthermore, supernatants were collected and proteins typical for bone remodelling were examined. The electrical stimulation did not exert a significant influence on the metabolic activity and the ALP production in cells over time using these settings. Gene expression of BSP and ALP was upregulated after the first 3 days whereas OPG was increased in the second half after 14 days of electrical stimulation. Moreover, the concentration of the released proteins OPG, IL-6, DKK-1 and OPN increased when cells were cultivated under electrical stimulation. However, no changes could be seen for essential markers, like RANKL, Leptin, BMP-2, IL-1beta and TNF-alpha. Therefore, further studies will be done with
Aseptic loosening has become the single most important long-term complication of total joint replacements. The pathophysiology of this loosening is multifactorial in origin ranging from mechanical wear, poor surgical technique, thermal damage and the inflammatory response to particulate wear debris. Cytokines are released in response to macrophage activation by particulate wear debris (PWD), the resultant inflammatory cascade stimulates osteoclastic resorption of bone. The failure of remodelling and repair mechanisms may be as a result of Osteonecrosis from cement (PMMA). Hypothesis: That PMMA increases
Titanium (Ti) is well known in orthopedic implant materials such as total hip replacement arthroplasty. Osseointegration of orthopedic implants is defined as the formation of a direct interface between the implant and the bone without intervening soft tissue. Unmodified Ti is not sufficient to complete adhesion between Ti surface and host bone with subsequent implant loosening over time and ultimately implant failure. An effective approach to enhance the biological activity of orthopedic implants and improve post-implantation healing is to modify the implant surface. The aim of this study was to investigate the effect of functionalized titanium (Ti) with alendronate (Aln) and bone morphogenic protein-2 (BMP-2) for enhancement of
Metal-on-metal (MoM) bearing technology, made of cobalt-chromium (Co-Cr) alloys, is being used in anticipation of extending the durability of hip replacements. Increasingly, concern has been expressed that long term exposure to Co2+ and Cr3+ could cause DNA damage and immune dysfunction; specifically a reduction in the circulating number of CD8+ cytotoxic cells. More recently, we reported that Co2+ and Cr3+ affected the differentiation of osteoclast precursors into bone-resorbing osteoclasts. Despite these observations the effects of metal ions on
Recent studies have shown that random disorder nanotopography increases
Enzymes that breakdown components of the extracellular matrix (ECM) are of fundamental importance, not only in normal bone physiology but also in pathological processes. For instance the temporal and spatial distribution of proteoglycans is not only critical for the mineralisation of bone but is also believed to be responsible for dictating the local bioavailability of glycosaminoglycan-binding growth factors. A sub-family of the ADAMs (a disintegrin and metalloproteinase) has been identified, that contains thrombospondin-like motifs (ADAMTS), and ADAMTS1, 4 and 5 have recently been shown to cleave the major proteoglycan of cartilage, aggrecan. We propose that ADAMTS family members play a novel role in regulating
Orthopaedic surgeons are astounded with the strength of bone found in Polynesians. Furthermore the rate at which new Polynesian bone over-grows metal fixation of a recent fracture is impressive. Studies demonstrate that Polynesians have a higher Bone Mineral Density (BMD) than age and weight matched Europeans in NZ (1, 2). In addition, Polynesians have a lower incidence of hip fractures when compared to other ethnic groups (3). This suggests that the higher BMD or other inherent differences must account for the lower incidence of hip fractures in Polynesians. The aim of this study was to identify (if any) a difference in
Delayed facture repair and bony non-unions pose a clinical challenge. Understandably, novel methods to enhance bone healing have been studied by researchers worldwide. Electrical stimulation (ES) has shown to be effective in enhancing bone healing, however the best wave form and mechanism by which it stimulates
Caveolae, specialised regions of the cell membrane which have been detected in a wide range of mammalian cells, have not been described in bone cells. They are plasmalemmal invaginations, 50 to 100 nm in size, characterised by the presence of the structural protein, caveolin, which exists as three subtypes. Caveolin-1 and caveolin-2 are expressed in a wide range of cell types whereas caveolin-3 is thought to be a muscle-specific subtype. There is little information on the precise function of caveolae, but it has been proposed that they play an important role in signal transduction. As the principal bone-producing cell, the
Introduction and Aims: To deliver osteogenic cells into bone defects, the crucial steps are cell attachment and migration in cell-delivery biomaterials. The aim of this study was to examine whether complexes comprised of vitronectin (VN), insulin growth factors (IGFs) and insulin growth factor binding proteins (IGFBPs) could enhance human
One way to improve orthopaedic materials is to understand the exact architectural parameters that influence bone cell behaviour. In this study substrates with highly controlled surface features were created using photo-lithographic processes. These surfaces were contrasted for their ability to influence
Purpose: Vascular Endothelial Growth Factor (VEGF) plays an important role in promoting angiogenesis and osteogenesis during fracture repair. Our previous studies have shown that cell-based VEGF gene therapy accelerates bone healing of a rabbit tibia segmental bone defect in-vivo, and increases
Introduction: Several recent studies have highlighted the influence of topographical features on the response of cells to biomaterial surfaces, both in terms of their adhesion, morphology and gene expression. Initial cell adhesion events are believed to be pivotal in dictating subsequent host response to implant materials and therefore understanding the mechansims that regulate these events is fundemental to the design and engineering of the next generation of biomaterials. In our studies we evaluated the adhesion associated events of
Nowadays, biomaterials can be used to maintain or replace several functions of the human body being constricted or lost due to tumors, fractures, injuries as well as chronic diseases, infections or simply aging. Titanium and its alloys, i.e. Ti6Al4V are the most common materials (70 to 80%) used for structural orthopedic implants due to their unique combination of good mechanical properties, corrosion resistance and biocompatibility. Addition of β-stabilizers, e. g. niobium (Nb), can improve the mechanical properties of such titanium alloys further, simultaneously offering excellent biocompatibility. Previous studies concerning biocompatibility analyses with niobium and especially Ti-42Nb specimens are rarely described; none for niobium and Ti-42Nb powders examining human cell viability, collagen and interleukin synthesis. In this in vitro study, human
We cultured human
We have studied in vitro the effect of a hydroxyapatite (HA) tricalcium phosphate material coated with hepatocyte growth factor (HA-HGF) on cell growth, collagen synthesis and secretion of metalloproteinases (MMPs) by human
High-pressure lavage produces greater visible damage to bone at a macroscopic and microscopic level when compared with low-pressure lavage and can result in delay in the healing of fractures. Osteoblasts and adipocytes are derived from mesenchymal stem cells. Conditions which lead to bone loss often involve a switch from the
Unlike most other tumours, myeloma causes bone destruction without an osteoblastic reaction; we tried to assess whether myeloma secretes a humoral factor that inhibits
Purpose: Apoptosis of
Interactions between cells and polymers are mediated by proteins, which are either secreted by cells and immobilized on the biomaterial surface, or absorbed from the medium. Poly (lactic acid) (PLA) is widely used in tissue engineering as a scaffold material, however anchorage-dependent cells such as
Fracture healing continues to pose challenges for researchers and clinicians in the field of trauma and orthopaedic surgery. The future treatment strategies for fracture healing will most likely focus on the use of biologic and biochemical methods in combination with established fixation and mechanical methods. In this study, heparanase (HPSE), a mammalian endo-glycuronidase that promotes angiogenesis through cleavage of the extra cellular matrix (ECM)-heparan sulphate and mobilization of ECM resident growth factors, was investigated for its osteoblasts-stimulating effect.
Introduction: The mitochondrial Translocator Protein 18 kDa (TSPO, previously named as the peripheral benzodiazepine receptor - PBR) is involved in cellular respiration, steroidogenesis and apoptosis. In our recent study we reported on the role of the synthetic pharmacological ligands to the TSPO in enhancing human
A non-invasive technique for labelling S phase
Purpose: Peri-implant osteolysis after total joint arhtro-plasty (TJA) is a major cause of implant loosening. Cellular responses to wear particles have been reported to play a role in asceptic loosening due to their cytotoxic nature to cellular components. Purpose of this study is to evaluate the effect of orthopedic implant wear particles on immature
Bacterial contamination of endoprostheses especially in revision surgery is an upcoming problem according to increasing number of joint replacements. Early adherence of bacteria producing a biofilm is difficult to treat. Silver coating of implants offers the opportunity to avoid bacterial adhesions acting against all relevant bacteria causing infections on the implant. We developed a new technique of nano-silver coating using elemental silver covered with SiOxCy whose thickness can be varied determing duration of the coating on the implant. The SiOxCy and silver is completely soluble at least at 3 months. The silver coatings used so far are measuring at least 10um and they are not soluble making a cementless implantation of the endoprostheses impossible. The aim of this study was to test the compatibility of the new combined coating with human
There is increasing evidence that non-steroidal anti-inflammatory drugs (NSAIDs) can adversely affect bone repair. We have, therefore, studied the in vitro effects of NSAIDs, which differentially inhibit cyclooxygenases (COX), the prostaglandin/thromboxane synthesising enzymes, on human
We developed a 3D vascularized bone remodeling model embedding human
Background: Low molecular weight heparins (LMWH) are of undoubted efficacy as thromboprophylaxis in orthopaedic surgical practice. However, prolonged dosage inhibits bone nodule formation in vitro and we have previously reported that daily dosing significantly delays fracture healing. To further investigate these phenomena we hypothesised that LMWH’s would reduce
This basic science study attempts to explain why patients with spinal cord injuries have been seen to display increased healing of attendant fractures. For the main part, this has been a clinical observation with laboratory work confined to rats. While the benefits in relation to quicker fracture healing are obvious, this excessive bone growth (heterotopic ossification) also causes unwanted side effects, such as decreased movement around joints, joint fusion and renal tract calculi. However, the cause for this phenomenon remains unclear. This paper evaluates two group with spinal column fractures – those with neurological compromise (n=10) and those without (n=11), and compares them with a control group with isolated long bone fractures (n=10). Serum was taken from these patients at five specific time intervals post injury (24hrs, 120hrs, 10 days, 6 weeks and 12 weeks). The time period most closely related to the end of the acute inflammatory reaction and the laying down of callus was the 10-day post injury time period. Serum samples taken at this time period were analysed for IGF-1 and TGF-ß levels, both known to initiate osteoblastic activity, using ELISA kits. They were also exposed to an
In biomaterial engineering the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. Increased bone marrow derived mesenchymal stromal cell (BMSC) differentiation towards bone forming
Background Apoptosis of
We aimed to determine whether development of heterotopic ossification (HO) following THA might be predicted by early changes in biochemical markers of bone turnover. The study cohort consisted of 21 men and women taking part in a randomised trial of the bisphosphonate pamidronate in the prevention of bone loss following THA. All had under gone unilateral THA using the same design of implant and all were assigned to placebo in the trial. The
Summary Statement. Developing titanium (Ti) surfaces that are biocompatible yet serve as deterrents for bacterial attachment and growth are particularly appealing in tackling the ongoing problem of sepsis-induced implant failures. Realising this could include coating Ti with the bioactive lipid, lysophosphatidic acid. Introduction. Surgical revision for failed total joint replacements costs a staggering £300m/yr and approximately 20% of this burden is attributed to implant failure through bacterial infection. Producing biomaterials that deter microbial attachment as well as securing robust osseointegration continues to be a significant research challenge in contemporary bone biomaterials design. Steps to realising novel improvements are further compounded by the concerns raised over resistance of bacteria to many antimicrobial agents. Clearly this is a major constraint necessitating an entirely novel approach to minimising implant infection risk. We therefore turned our attention to certain lysophosphatidic acids (LPAs) for Ti functionalisation. We have found LPA to enhance calcitriol-induced human
Synthetic biodegradable polymers have been utilized increasingly in pharmaceutical, medical and biomedical engineering. Control of the interaction of living cells and biomaterials surfaces is one of the major goals in the design and development of new polymeric biomaterials in tissue engineering. In this study, a novel amphiphilic tri-block copolymer, methoxy-terminated poly (ethylene glycol) (MPEG) – polyL-lactide (PLLA) – polylysine (PLL) was synthesized. Various molecular compositions of tri-block copolymers were prepared via optimising the parameters and characterized through Nuclear Magnetic Resonance and Gel Permeation Chromatography. The tri-block copolymer was then mixed with high molecular weight PLLA to form a flat film. The surface properties measured by X-ray Photoelectron Spectroscopy and Atomic Force Microscopy demonstrated high content of the PLL on the surface of PLLA film, which indicated self-segregation of MPEG-b-PLLA-b-PLL on PLLA surface. No cytotoxicity was detected in triblock copolymers, and compared to pure PLLA and diblock copolymers, the triblock copolymers were much more effective for cell adhesion and proliferation. It was noted that the hydrophilic chain of PEG and PLL stretched out and formed an outer layer, especially under the aqueous environment, which resulted in enhanced cell attachment and proliferation. The self-segregation behaviour of MPEG-b-PLLA-b-PLL triblock copolymer shows a potential application in scaffold preparation of tissue engineering.
Mechanical loading of bone is anabolic, while aseptic loosening of implants is catabolic. In a rat model of mechanically induced aseptic loosening, osteoclast differentiation is increased dramatically but the underlying mechanism is unknown. The objective was to profile molecular pathways in peri-implant bone resorption. Microarrays on cortical bone samples exposed to pressurized fluid flow were performed 3, 6, 12, 24 and 36 hrs, using time 0 as controls. Of a total of 4093 genes that underwent a 1.25-fold change (p<0.05) due to fluid flow only 21 were common for all time points. Signals linked to inflammation and apoptosis were regulated in a biphasic manner at 3 and 12 and/or 24 hrs. The acute response at 3 hrs was associated with increases in the cytokines IL-6, IL-11, LIF and STAT3. Levels of the pro-apoptotic factor TWEAK were higher while those of BOK, a second pro-survival molecule, were lower. There is an early and late rise in RIPK3, which stimulates a form of programmed necrosis. Osteoblast-related genes were clearly suppressed (osteocalcin, Col1a, PTHr1), while those regulating macrophage and osteoclast differentiation (CSF-1, Bach1, HO-1, RANKL, RANK, OPG) were enhanced. These data suggest that mechanical loading of cortical bone stimulates time-dependent expression of genes regulating the survival, necrosis and differentiation of both the myeloid and mesenchymal cell lineages, resulting in an integrated response leading to a rapid increase in osteoclast numbers.
We previously reported that
Aims. Long non-coding RNAs (lncRNAs) act as crucial regulators in osteoporosis (OP). Nonetheless, the effects and potential molecular mechanism of lncRNA PCBP1 Antisense RNA 1 (PCBP1-AS1) on OP remain largely unclear. The aim of this study was to explore the role of lncRNA PCBP1-AS1 in the pathogenesis of OP. Methods. Using quantitative real-time polymerase chain reaction (qRT-PCR), osteogenesis-related genes (alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OPN), and Runt-related transcription factor 2 (RUNX2)), PCBP1-AS1, microRNA (miR)-126-5p, group I Pak family member p21-activated kinase 2 (PAK2), and their relative expression levels were determined. Western blotting was used to examine the expression of PAK2 protein. Cell Counting Kit-8 (CCK-8) assay was used to measure cell proliferation. To examine the osteogenic differentiation, Alizarin red along with ALP staining was used. RNA immunoprecipitation assay and bioinformatics analysis, as well as a dual-luciferase reporter, were used to study the association between PCBP1-AS1, PAK2, and miR-126-5p. Results. The expression of PCBP1-AS1 was pre-eminent in OP tissues and decreased throughout the development of human bone marrow-derived mesenchymal stem cells (hBMSCs) into
Aims. This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in
Aims. The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI. Methods. Periprosthetic femoral trabecular bone specimens were obtained from patients suffering from chronic PJI of the hip and knee (n = 20). Microbiological analysis was performed on preoperative joint aspirates and tissue specimens obtained during revision surgery. Microstructural and cellular bone parameters were analyzed in bone specimens by histomorphometry on undecalcified sections complemented by tartrate-resistant acid phosphatase immunohistochemistry. Data were compared with control specimens obtained during primary arthroplasty (n = 20) and aseptic revision (n = 20). Results. PJI specimens exhibited a higher bone volume, thickened trabeculae, and increased osteoid parameters compared to both control groups, suggesting an accelerated bone turnover with sclerotic microstructure. On the cellular level,
Aims. Osteoporosis is characterized by decreased trabecular bone volume, and microarchitectural deterioration in the medullary cavity. Interleukin-19 (IL-19), a member of the IL-10 family, is an anti-inflammatory cytokine produced primarily by macrophages. The aim of our study was to investigate the effect of IL-19 on osteoporosis. Methods. Blood and femoral bone marrow suspension IL-19 levels were first measured in the lipopolysaccharide (LPS)-induced bone loss model. Small interfering RNA (siRNA) was applied to knock down IL-19 for further validation. Thereafter, osteoclast production was stimulated with IL-19 in combination with mouse macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL). The effect of IL-19 was subsequently evaluated using tartrate-resistant acid phosphatase (TRAP) staining and quantitative real-time polymerase chain reaction (RT-qPCR). The effect of IL-19 on osteoprotegerin (OPG) was then assessed using in vitro recombinant IL-19 treatment of primary
Aims. Exosomes derived from bone marrow mesenchymal stem cells (BMSCs) have been reported to be a promising cellular therapeutic approach for various human diseases. The current study aimed to investigate the mechanism of BMSC-derived exosomes carrying microRNA (miR)-136-5p in fracture healing. Methods. A mouse fracture model was initially established by surgical means. Exosomes were isolated from BMSCs from mice. The endocytosis of the mouse
Bone homeostasis is a highly regulated process involving pathways in bone as WNT, FGF or BMP, but also requiring support from surrounding tissues as vessels and nerves. In bone diseases, the bone-vessel-nerve triad is impacted. Recently, new players appeared as regulators of bone homeostasis: microRNAs (miRNA). Five miRNAs associated with osteoporotic fractures are already known, among which miR-125b is decreasing bone formation by downregulating human mesenchymal stem cells (hMSCs) differentiation. Other miRNAs, as miR-214 (in cluster with miR-199a), are secreted by osteoclasts to regulate
Aims. Astragalus polysaccharide (APS) participates in various processes, such as the enhancement of immunity and inhibition of tumours. APS can affect osteoporosis (OP) by regulating the osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs). This study was designed to elucidate the mechanism of APS in hBMSC proliferation and
Aim. Bone regeneration following the treatment of Staphylococcal bone infection or osteomyelitis is challenging due to the ability of Staphylococcus aureus to invade and persist within bone cells, which could possibly lead to antimicrobial tolerance and incessant bone destruction. Here, we investigated the influence of Staphylococcal bone infection on
Mesenchymal stem cells (MSC) have potent immunomodulatory and regenerative effects via soluble factors. One approach to improve stem cell-based therapies is encapsulation of MSC in hydrogels based on natural proteins such as collagen and fibrin, which play critical roles in bone healing. In this work, we comparatively studied the influence of collagen and fibrin hydrogels of varying stiffness on the paracrine interactions established by MSC with macrophages and
The effect of high-fat diet and testosterone replacement therapy upon bone remodelling was investigated in orchiectomised male APOE-/- mice. Mice were split in to three groups: sham surgery + placebo treatment (control, n=9), orchiectomy plus placebo treatment (n=8) and orchiectomy plus testosterone treatment (n=10). Treatments were administered via intramuscular injection once a fortnight for 17 weeks before sacrifice at 25 weeks of age. Tibiae were scanned ex-vivo using µCT followed by post-analysis histology and immunohistochemistry. Previously presented µCT data demonstrated orchiectomised, placebo treated mice exhibited significantly reduced trabecular bone volume, number, thickness and BMD compared to control mice despite no significant differences in body weight. Trabecular parameters were rescued back to control levels in orchiectomised mice treated with testosterone. No significant differences were observed in the cortical bone. Assessment of TRAP stained FFPE sections revealed no significant differences in osteoclast or
Total hip replacement (THR) is indicated for patients with osteoarthritis where conservative treatment has failed. Metal alloys used in THR implants such as cobalt-chromium (CoCr) have been known to cause pro-inflammatory reactions in patients, therefore leading to the need for costly revision surgery. This study therefore aimed to investigate the role of TLR4 in the activation of a human
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
To design slow resorption patient-specific bone graft whose properties of bone regeneration are increased by its geometry and composition and to assess it in in-vitro and in-vivo models. A graft composed by hydroxyapatite (HA) and β-TCP was designed as a cylinder with 3D gyroid porosities and 7 mm medullary space based on swine's anatomy. It was produced using a stereolithography 3D-printing machine (V6000, Prodways). Sterile bone grafts impregnated with or without a 10µg/mL porcine BMP-2 (pBMP-2) solution were implanted into porcine femurs in a bone loss model. Bone defect was bi-weekly evaluated by X-ray during 3 months. After sacrifice, microscanner and non-decalcified histology analysis were conducted on biopsies. Finally,
We have developed a novel technique to analyse bone, using imaging mass cytometry (IMC) without the constraints of using immunofluorescent histochemistry. IMC can measure the expression of over 40 proteins simultaneously, without autofluorescence. We analysed mitochondrial respiratory chain (RC) protein deficiencies in human bone which are thought to contribute to osteoporosis with increasing age. Osteoporosis is characterised by reduced bone mineral density (BMD) and fragility fractures. Humans accumulate mitochondrial mutations and RC deficiency with age and this has been linked to the changing phenotype in advancing age and age-related disease. Mitochondrial mutations are detectable from the age of 30 onwards, coincidently the age BMD begins to decline. Mitochondria contain their own genome which accumulates somatic variants at around 10 times the rate of nuclear DNA. Once these mutations exceed a threshold, RC deficiency and cellular dysfunction occur. The PolgD257A/D257A mouse model expresses a proof-reading deficient version of PolgA, a mtDNA polymerase. These mice accumulate mutations 3-5 times higher than wild-type mice showing enhanced levels of age-related osteoporosis and RC deficiency in
Aim. Here, we are aimed to evaluate bacteriophage (191219) to treat S. aureus implant-associated bone infections by means of testing against S. aureus during its planktonic, biofilm and intracellular growth phases and finally assessing antimicrobial effect on in vivo biofilm formed on metal K-wire in an alternative insect model Galleria mellonella. Method. The bacteriophages (191219) were provided from D&D Pharma GmbH. These bacteriophages were tested against S. aureus EDCC 5055 (MSSA) and S. aureus DSM 21979 (MRSA) strains. To assess the activity of bacteriophages against planktonic growth phase, bacteriophages, and S. aureus EDCC 5055(1×10. 7. CFU/ml) were co-cultured in LB media as multiplicity of infection (MOI) of 10, 1, 0.1, and 0.01 for 24 hours at 37. o. C and finally plated out on the LB agar plates to estimate the bacterial growth. The antimicrobial activity of bacteriophages on biofilms in vitro was measured by analysing the incubating the several fold dilutions of bacteriophages in LB media with biofilms formed on 96-well plate. The eradication of biofilm was analysed with crystal violet as well as CFU analysis methods. Later, the effect of bacteriophages on intracellular growth of S. aureus in side
Introduction and Objective. Senescent bone cell overburden accelerates osteoporosis. Epigenetic alteration, including microRNA signalling and DND methylation, is one of prominent features of cellular senescence. This study aimed to investigate what role microRNA-29a signalling may play in the development of senile osteoporosis. Materials and Methods. Bone biopsy and serum were harvested from 13 young patients and 15 senior patients who required spine surgery. Bone mass, microstructure, and biomechanics of miR-29a knockout mice (miR-29aKO) and miR-29a transgenic mice (miR-29aTg) were probed using mCT imaging and three-point bending material test. Senescent cells were probed using senescence-associated b-galactosidase (SA-b-gal) staining. Transcriptomic landscapes of
Aims. Circular RNA (circRNA) is involved in the regulation of articular cartilage degeneration induced by inflammatory factors or oxidative stress. In a previous study, we found that the expression of circStrn3 was significantly reduced in chondrocytes of osteoarthritis (OA) patients and OA mice. Therefore, the aim of this paper was to explore the role and mechanism of circStrn3 in osteoarthritis. Methods. Minus RNA sequencing, fluorescence in situ hybridization, and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the expression of circStrn3 in human and mouse OA cartilage tissues and chondrocytes. Chondrocytes were then stimulated to secrete exosomal miR-9-5p by cyclic tensile strain. Intra-articular injection of exosomal miR-9-5p into the model induced by destabilized medial meniscus (DMM) surgery was conducted to alleviate OA progression. Results. Tensile strain could decrease the expression of circStrn3 in chondrocytes. CircStrn3 expression was significantly decreased in human and mouse OA cartilage tissues and chondrocytes. CircStrn3 could inhibit matrix metabolism of chondrocytes through competitively ‘sponging’ miRNA-9-5p targeting Kruppel-like factor 5 (KLF5), indicating that the decrease in circStrn3 might be a protective factor in mechanical instability-induced OA. The tensile strain stimulated chondrocytes to secrete exosomal miR-9-5p. Exosomes with high miR-9-5p expression from chondrocytes could inhibit
Several synthetic polymers have been widely investigated for their use in bone tissue engineering applications, but the ideal material is yet to be engineered. Triazine-trione (TATO) based materials and their derivatives are novel in the field of biomedical engineering but have started to draw interest. Different designs of the TATO monomers and introduction of different chemical linkages and end-groups widens the scope of the materials due to a range of mechanical properties. The aim of our work is to investigate novel TATO based materials, with or without hydroxyapatite filler, for their potential in bone tissue engineering constructs. Initially the biocompatibility of the materials was tested, indirectly and directly, according to ISO standards. Following this the osteoconductive properties were investigated with primary
Aims. This study aimed to explore the role of small colony variants (SCVs) of Staphylococcus aureus in intraosseous invasion and colonization in patients with periprosthetic joint infection (PJI). Methods. A PJI diagnosis was made according to the MusculoSkeletal Infection Society (MSIS) for PJI. Bone and tissue samples were collected intraoperatively and the intracellular invasion and intraosseous colonization were detected. Transcriptomics of PJI samples were analyzed and verified by polymerase chain reaction (PCR). Results. SCVs can be isolated from samples collected from chronic PJIs intraoperatively. Transmission electron microscopy (TEM) and immunofluorescence (IF) showed that there was more S. aureus in bone samples collected from chronic PJIs, but much less in bone samples from acute PJIs, providing a potential mechanism of PJI. Immunofluorescence results showed that SCVs of S. aureus were more likely to invade
Growth factors produced by inflammatory cells and mesenchymal progenitors are required for proper bone regeneration. Signaling pathways activated downstream of these proteins work in concert and synergistically to drive
Aims. Transcription factor nuclear factor kappa B (NF-κB) plays a major role in the pathogenesis of chronic inflammatory diseases in all organ systems. Despite its importance, NF-κB targeted drug therapy to mitigate chronic inflammation has had limited success in preclinical studies. We hypothesized that sex differences affect the response to NF-κB treatment during chronic inflammation in bone. This study investigated the therapeutic effects of NF-κB decoy oligodeoxynucleotides (ODN) during chronic inflammation in male and female mice. Methods. We used a murine model of chronic inflammation induced by continuous intramedullary delivery of lipopolysaccharide-contaminated polyethylene particles (cPE) using an osmotic pump. Specimens were evaluated using micro-CT and histomorphometric analyses. Sex-specific osteogenic and osteoclastic differentiation potentials were also investigated in vitro, including alkaline phosphatase, Alizarin Red, tartrate-resistant acid phosphatase staining, and gene expression using reverse transcription polymerase chain reaction (RT-PCR). Results. Local delivery of NF-κB decoy ODN in vivo increased osteogenesis in males, but not females, in the presence of chronic inflammation induced by cPE. Bone resorption activity was decreased in both sexes. In vitro osteogenic and osteoclastic differentiation assays during inflammatory conditions did not reveal differences among the groups. Receptor activator of nuclear factor kappa Β ligand (Rankl) gene expression by
Critical size bone defects deriving from large bone loss are an unmet clinical challenge1. To account for disadvantages with clinical treatments, researchers focus on designing biological substitutes, which mimic endogenous healing through osteogenic differentiation promotion. Some studies have however suggested that this notion fails to consider the full complexity of native bone with respect to the interplay between osteoclast and
Introduction and Objective. Total joint replacement (TJR) is indicated for patients with end-stage osteoarthritis (OA) where conservative treatment has failed. Approximately 1.3 million primary hip replacement surgeries have been recorded in the United Kingdom since 2003 and this number is set to rise due to an increase in obesity as well as an ageing population. Total hip replacement (THR) has a survival rate of 85% at 20 years; the most common reason for failure is aseptic loosening which often occurs secondary to osteolysis caused by immune-mediated inflammation responses to wear debris generated from the materials used in the THR implant. Therefore, by understanding the biological steps by which biomaterials cause immune-mediated reactions it should be possible to prevent them in the future thereby reducing the number of costly revision surgeries required. Materials and Methods. The human osteoblast-like cell line (MG-63) was seeded at a density of 100,000 cell per well of a 6-well plate and treated with and increasing doses (0.5, 5, and 50mm. 3. per cell) of cobalt-chromium (CoCr) particles generated on a six-station pin-on-plate wear generator or commercially available ceramic oxide nanopowders (Al. 2. O. 3. and ZrO. 2. ) for 24 hours. TNF-alpha was used as a positive control and untreated cells as a negative control. Cells were then analysed by transmission electron microscopy (TEM) to determine whether the
One out of nine Canadian males would suffer prostate cancer (PC) during his lifetime. Life expectancy of males with PC has increased with modern therapy and 90% live >10 years. However, 20% of PC-affected males would develop incurable metastatic diseases. Bone metastases (BM) are present in ~80% of metastatic PC patients, and are the most severe complication of PC, generating severe pain, fractures, spinal cord compression, and death. Interestingly, PC-BMs are mostly osteoblastic. However, the structure of this newly formed bone and how it relates to pain and fracture are unknown. Due to androgen antagonist treatment, different PC phenotypes develop with differential dependency on androgen receptor (AR) signaling: androgen-dependent (AR+), double negative (AR-) and neuroendocrine. How these phenotypes are related to changes in bone structure has not been studied. Here we show a state-of-the-art structural characterization of PCBM and how PC phenotypes are associated to abnormal bone formation in PCBM. Cadaveric samples (n=14) obtained from metastases of PC in thoracic or lumbar vertebrae (mean age 74yo) were used to analyze bone structure. We used micro-computed tomography (mCT) to analyze the three-dimensional structure of the bone samples. After imaging, the samples were sectioned and one 3mm thick section was embedded in epoxy-resin, ground and polished. Scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) and quantitative backscattering electron (qBSE) imaging were used to determine mineral morphology and composition. Another section was used for histological analysis of the PC-affected bone. Collagen structure, fibril orientation and extracellular matrix composition were characterized using histochemistry. Additionally, we obtained biopsies of 3 PCBM patients undergoing emergency decompression surgery following vertebral fracture and used them for immunohistological characterization. By using mCT, we observed three dysmorphic bone patterns: osteolytic pattern with thinned trabecula of otherwise well-organized structures, osteoblastic pattern defined as accumulation of disorganized matrix deposited on pre-existing trabecula, and osteoblastic pattern with minimum residual trabecula and bone space dominated by accumulation of disorganized mineralized matrix. Comparing mCT data with patho/clinical parameters revealed a trend for higher bone density in males with larger PSA increase. Through histological sections, we observed that PC-affected bone, lacks collagen alignment structure, have a higher number of lacunae and increased amount of proteoglycans as decorin. Immunohistochemistry of biopsies revealed that PC-cells inside bone organize into two manners: i) glandular-like structures where cells maintain their polarization in the expression of prostate markers, ii) diffuse infiltrate that spreads along bone surfaces, with loss of cell polarity. These cells take direct contact with
Introduction and Objective. Mesenchymal stem cells (MSC) are attractive candidates for bone regeneration approaches. Benefits of MSC therapy are mainly attributed to paracrine effects via soluble factors, exerting both immunoregulatory and regenerative actions. Encapsulation of MSC in hydrogels prepared with extracellular matrix (ECM) proteins has been proposed as a strategy to enhance their survival and potentiate their function after implantation. Functional activity of MSC can be regulated by the physical and mechanical properties of their microenvironment. In this work, we investigated whether matrix stiffness can modulate the crosstalk between MSC encapsulated in collagen hydrogels with macrophages and
Previous studies have described an age-dependent distortion of bone microarchitecture for α-CGRP-deficient mice (3). In addition, we observed changes in cell survival and activity of
Fracture non-union can be as high as 20% in certain clinical scenarios and has a high associated socioeconomic burden. Boron has been shown to regulate the Wnt/β-catenin pathway in other bodily processes. However, this pathway is also critical for bone healing. Here we aim to demonstrate that the local delivery of boric acid can accelerate bone healing, as well as to elucidate how boric acid, via the regulationtheWnt/β-catenin pathway, impacts theosteogenic response of bone-derived osteoclasts and
Bone tissue engineering attempts at substituting critical size bone defects with scaffolds that can be primed with osteogenic cells, usually mesenchymal stem cells (MSC) from the bone marrow. Although overlooked, peripheral blood is a valuable source of MSC and circulating osteoprogenitors (COP), bearing a significant regenerative potential, and peripheral blood is easier to access than bone marrow. We thus studied osteodifferentiation of peripheral blood mononuclear cells (pbMNC) under different culture conditions, and how they compared to primary human
Aims. To characterize the intracellular penetration of
Aim. Staphylococcus aureus is the first causative agent of bone and joints infections (BJI). It causes difficult-to-treat infections because of its ability to form biofilms, and to be internalized and persist inside
Minimally invasive surgery for the restoration of bone tissues lost due to diseases and trauma is preferred by the health care system as the related costs are continuously increasing. Recently, efforts have been paid to optimize injectable calcium phosphate (CaP) cements which have been recognized as excellent alloplastic material for osseous augmentation because of their unique combination of osteoconductivity, biocompatibility and mouldability. The sol-gel synthesis approach appears to be the most suitable route towards performing injectable calcium phosphates. Different strategies used to prepare bioactive and osteoinductive injectable CaP are reported. CaP gels complexed with phosphoserine-tethered poly(ε-lysine) dendrons (G3-K PS) designed to interact with the ceramic phase and able to induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) is discussed. Recently, attention has been given to the modification of hydroxyapatite with Strontium (Sr) due to its dual mode of action, simultaneously increasing bone formation (stimulating
Aims. Circular RNAs (circRNAs) are a novel type of non-coding RNA that plays major roles in the development of diverse diseases including osteonecrosis of the femoral head (ONFH). Here, we explored the impact of hsa_circ_0066523 derived from forkhead box P1 (FOXP1) (also called circFOXP1) on bone mesenchymal stem cells (BMSCs), which is important for ONFH development. Methods. RNA or protein expression in BMSCs was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot, respectively. Cell Counting Kit 8 (CCK8) and 5-ethynyl-2’-deoxyuridine (EdU) were used to analyze cell proliferation. Alkaline phosphatase (ALP) activity, ALP staining, and Alizarin Red S staining were employed to evaluate the osteoblastic differentiation. Chromatin immunoprecipitation (ChIP), luciferase reporter, RNA pull down, and RNA immunoprecipitation (RIP) assays were combined for exploring molecular associations. Results. Circ_0066523 was upregulated in osteogenic induction process of BMSCs. Silencing circ_0066523 restrained the proliferation and osteogenic differentiation of BMSCs. Mechanistically, circ_0066523 activated phosphatidylinositol-4,5-bisphosphate 3-kinase / AKT serine/threonine kinase 1 (PI3K/AKT) pathway via recruiting lysine demethylase 5B (KDM5B) to epigenetically repress the transcription of phosphatase and tensin homolog (PTEN). Functionally, AKT signalling pathway agonist or PTEN knockdown counteracted the effects of silenced circ_0066523 on BMSC proliferation and differentiation. Conclusion. Circ_0066523 promotes the proliferation and differentiation of BMSCs by epigenetically repressing PTEN and therefore activating AKT pathway. This finding might open new avenues for the identification of therapeutic targets for
Objectives. Laser-engineered net shaping (LENS) of coated surfaces can overcome the limitations of conventional coating technologies. We compared the in vitro biological response with a titanium plasma spray (TPS)-coated titanium alloy (Ti6Al4V) surface with that of a Ti6Al4V surface coated with titanium using direct metal fabrication (DMF) with 3D printing technologies. Methods. The in vitro ability of human
Bone tissue engineering is a promising strategy to treat the huge number of bone fractures caused by progressive population ageing and diseases i.e., osteoporosis. The bioactive and biomimetic materials design modulating cell behaviour can support healthy bone tissue regeneration. In this frame, type I collagen and hydroxyapatite (HA) have been often combined to produce biomimetic scaffolds. In addition, mesoporous bioactive glasses (MBGs) are known for their ability to promote the deposition of HA nanocrystals and their potential to incorporate and release therapeutic ions. Furthermore, the use of 3D printing technologies enables the effective design of scaffolds reproducing the natural bone architecture. This study aims to design biomimetic and bioactive 3D printed scaffolds that mimic healthy bone tissue natural features in terms of chemical composition, topography and biochemical cues. Optimised collagenous hybrid systems will be processed by means of extrusion 3D printing technologies to obtain high resolution bone-like structures. Protocols of human co-cultures of
Introduction and Objective. Neoangiogenesis drives the replacement of mineralized cartilage by trabecular bone during bone growth regulated by molecules like e.g. VEGF, OPG and RANKL and the close interaction of progenitors of