Aims. The involvement of long non-coding RNA (lncRNA) in bone marrow mesenchymal stem cell (MSC) osteogenic differentiation during osteoporosis (OP) development has attracted much attention. In this study, we aimed to disclose how LINC01089 functions in human mesenchymal stem cell (hMSC) osteogenic differentiation, and to study the mechanism by which LINC01089 regulates MSC osteogenesis. Methods. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting were performed to analyze LINC01089, miR-1287-5p, and heat shock protein family A (HSP70) member 4 (HSPA4) expression. The osteogenic differentiation of MSCs was assessed through alkaline phosphatase (ALP) activity, alizarin red S (ARS) staining, and by measuring the levels of osteogenic gene marker expressions using commercial kits and RT-qPCR analysis. Cell proliferative capacity was evaluated via the Cell Counting Kit-8 (CCK-8) assay. The binding of miR-1287-5p with LINC01089 and HSPA4 was verified by performing dual-luciferase reporter and RNA immunoprecipitation (RIP) experiments. Results. LINC01089 expression was reinforced in serum samples of OP patients, but it gradually diminished while hMSCs underwent osteogenic differentiation. LINC01089 knockdown facilitated hMSC osteogenic differentiation. This was substantiated by: the increase in ALP activity; ALP, runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osteopontin (OPN) messenger RNA (mRNA) levels; and level of ARS staining. Meanwhile, LINC01089 upregulation resulted in the opposite effects. LINC01089 targeted miR-1287-5p, and the LINC01089 knockdown-induced hMSC osteogenic differentiation was repressed by miR-1287-5p depletion. HSPA4 is a downstream function molecule of the LINC01089/miR-1287-5p pathway; miR-1287-5p negatively modulated HSPA4 levels and attenuated its functional effects. Conclusion. LINC01089 negatively regulated hMSC osteogenic differentiation, at least in part, via governing miR-1287-5p/HSPA4 signalling. These findings provide new insights into hMSC osteogenesis and bone metabolism. Cite this article: Bone Joint Res 2024;13(12):779–789

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Mesenchymal stem cells (MSCs) are usually cultured in a normoxic atmosphere (21%) in vitro, while the oxygen concentrations in human tissues and organs are 1% to 10% when the cells are transplanted in vivo. However, the impact of hypoxia on MSCs has not been deeply studied, especially its translational application.

Addressing bone defects is a complex medical challenge that involves dealing with various skeletal conditions, including fractures, osteoporosis (OP), bone tumours, and bone infection defects. Despite the availability of multiple conventional treatments for these skeletal conditions, numerous limitations and unresolved issues persist. As a solution, advancements in biomedical materials have recently resulted in novel therapeutic concepts. As an emerging biomaterial for bone defect treatment, graphene oxide (GO) in particular has gained substantial attention from researchers due to its potential applications and prospects. In other words, GO scaffolds have demonstrated remarkable potential for bone defect treatment. Furthermore, GO-loaded biomaterials can promote osteoblast adhesion, proliferation, and differentiation while stimulating bone matrix deposition and formation. Given their favourable biocompatibility and osteoinductive capabilities, these materials offer a novel therapeutic avenue for bone tissue regeneration and repair. This comprehensive review systematically outlines GO scaffolds’ diverse roles and potential applications in bone defect treatment.

Cite this article: Bone Joint Res 2024;13(12):725–740.

The December 2024 Oncology Roundup³⁶⁰ looks at: Non-reversed great saphenous vein grafts for vascular reconstruction after resection of lower limb sarcoma; Detrimental effects of COVID-19 pandemic on patients with limb bone sarcoma: reference centre experience; Whole-body staging guidelines in sarcoma; Intraoperative marrow margin frozen section in limb bone sarcoma resection; Vacuum-assisted closure and paediatric oncological limb salvage; Treatment differences and long-term outcomes in adults and children with Ewing’s sarcoma; Survival, complications, and functional outcomes of uncemented distal femoral endoprosthesis with short, curved stem for patients with bone tumours.

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Pain is the most frequent complaint associated with osteonecrosis of the femoral head (ONFH), but the factors contributing to such pain are poorly understood. This study explored diverse demographic, clinical, radiological, psychological, and neurophysiological factors for their potential contribution to pain in patients with ONFH.

Background. The molecular mechanisms underlying non-union bone fractures largely remain elusive. Recently, spatial transcriptomics approaches for musculoskeletal tissue samples have been developed requiring direct placement of histology sections on barcoded slides. However, Formalin-Fixed-Paraffin-Embedded (FFPE) bone sections have been associated with limited RNA quality and read depth compared to soft tissue. Here, we test spatial transcriptomics workflows based on transcriptomic probe transfer to characterize molecular features discriminating non-union and union bone fractures in mice. Method. Histological sections (n=8) used for spatial transcriptomics (Visium CytAssist FFPE; 10x Genomics, n=4 on glass slides, n=4 on hydrogel-coated slides) were obtained from a fracture healing study in female 20-week-old C57BL/6J mice receiving either a femur osteotomy (0.7mm) or a segmental defect (2.4mm) (license 22/2022, Grisons CH). Sequence alignment and manual segmentation of different tissues (bone, defect region/callus, bone marrow, muscle) were performed using SpaceRanger and LoupeBrowser (10x Genomics). Differential gene expression was performed using DESeq2 (Seurat) followed by Gene-Set-Enrichment-Analysis (GSEA) of Gene Ontology (ClusterProfiler). Group comparison of quality measures was done using a Welch's t-test. Results are given as mean±standard deviation. Result. The quality measures, mean counts, and genes per spot, were significantly ~10× higher for sections on hydrogel slides (counts: 4700±1796, genes: 2389±1170) compared to glass slides (counts: 463±415, genes: 250±223). In challenging tissues like cortical bone, we reached high counts+genes in comparison to published data. Direct comparison of a non-union and union section showed a total of 432 differentially regulated genes, 538 in the defect region/callus. GSEA revealed differential regulation of pathways involved in muscle organ morphogenesis, cartilage development and endochondral ossification. Conclusions. Optimized spatial transcriptomics workflows based on transcriptomic probe transfer enable for improved read depth in musculoskeletal tissue enabling the characterization of molecular features discriminating non-union and union bone fractures. Acknowledgements. AO Foundation (AOTRAUMA), SNSF (PhD salary)

Introduction. Bioactive glasses (BGs) promote osteogenic differentiation of bone progenitor cells by releasing therapeutically active ions. The well-described 45S5-BG (in mol%: SiO. 2. 46.13; P. 2. O. 5. 2.60; CaO 26.91; Na. 2. O 24.35) was supplemented with CaF. 2. and NaF being added to the batch at nominal 5 (F5-BG) and 25 mol% (F25-BG), respectively. While the effect on physical and chemical properties has already been characterized, the biological properties require further studies. This study investigates the effects of fluoride-supplemented BGs on the osteogenic and angiogenic properties of human bone marrow mesenchymal stromal cells (BMSCs) in vitro. Method. BMSCs were co-cultured with melt-derived 45S5-BG, F5-BG, or F25-BG in ascending concentrations (1, 2 and 3 mg/ml). At 7 days, cell number was determined by 4,6-diamidine-2-phenylindole (DAPI) staining and cell viability by fluorescein diacetate (FDA) assay. The osteogenic potential of the BGs was evaluated through alkaline phosphatase (ALP) gene expression and activity, along with bone morphogenetic protein-2 (BMP2) gene expression and protein concentration. Vascular endothelial growth factor (VEGF) gene expression and protein concentration assessed angiogenic potential. As control, BMSCs were cultured without BG exposure. Result. All BGs significantly promoted cell number and viability, with F25-BG showing the highest count at 3 mg/ml. Osteogenic markers showed a significant decrease in ALP gene expression and activity, especially at higher concentrations. All BG groups demonstrated increased BMP2 protein concentration and gene expression compared to the control, with higher BG and fluoride concentrations correlating with greater increases in BMP2. VEGF gene expression increased in all analysed BGs. The fluoride-free BG group had the highest VEGF protein concentrations, while the F25 BG group showed the highest VEGF gene expression. Conclusion. The fluoride-substituted BGs exhibit excellent cytocompatibility, enhance BMSC proliferation and positively affect BMP2 gene expression and levels, suggesting their potential for osteogenic differentiation. Further research is necessary to assess their proangiogenic effect and potential advantages over 45S5-BG

Introduction. Femoral head osteonecrosis (FHO) is a condition in which the inadequate blood supply disrupts osteogenic-angiogenic coupling that results in diminishment of femoral perfusion and ends up with FHO. The insufficient knowledge on molecular background and progression pattern of FHO and the restrictions in obtaining human samples bring out the need for a small animal trauma model to research FHO aetiology. Hence, this study aims to develop a mouse trauma model to elucidate the molecular mechanisms behind FHO. Method. Left femoral head was dislocated from the hip joint, ligamentum teres was cut, and a slight circular incision was done around the femoral neck of 8-week-old male C57BL/6J mice to disrupt the blood supply to femoral head. Right hip joint was left unoperated as control. Animals (n=5 per time point) were sacrificed on 2-3-4-6-8-10-12 weeks, and ex-vivo µCT was taken to assess bone structural parameters. Haematoxylin/eosin (HE)- and immunohistochemical-staining (IHCS) for CD31 and EMCN were done to observe histology and marrow-specific H-type vascular structures, respectively. Result. μCT assessment showed trabecular bone loss and decreased BV/TV from 2 to 8 weeks in FHO side. HE staining displayed the increased number of empty lacunae was observed in FHO side as early as 24h after operation. By 4. th. week, IHCS results displayed the invasion of the epiphyseal plate by H-type blood vessels in FHO side, while the epiphyseal plate was observed intact in control side. Also, by 6. th. week the HE-staining showed the presence of bone marrow necrosis and bone fat accumulation in FHO side. Conclusion. Trabecular bone loss, increased number of empty lacunae, bone fat imbalance and bone marrow necrosis are reported as the signs of osteonecrosis. Thus, our results are coherent with the literature and indicated that we were able to effectively generate a trauma model for FHO in mice for the first time in literature

Introduction. Bereft of their optimal tissue context, cells lose their phenotype, function and therapeutic potential during in vitro culture. Despite the fact that in vivo cells are exposed simultaneously to multiple signals, traditional ex vivo cultures are monofactorial. With these in mind, herein we assessed the combined effect of surface topography, substrate rigidity, collagen type I coating and macromolecular crowding in human tenocyte, skin fibroblast and bone marrow mesenchymal stromal cell cultures. Methods. Thermal imprinted was used to pattern (groove depth: 2,000 nm, groove width: 2,000 nm, line width: 2,000 nm) polydimethylsiloxane substrates of different rigidity (50 kPa, 130 kPa, 1,000 kPa). Grooved and planar substrates were subsequently coated with collagen type I and used to culture the aforementioned cell populations without and with macromolecular crowding (100 μg/ml carrageenan). After 3, 7 and 14 days in culture, cell morphology, viability, metabolic activity, proliferation, protein synthesis and deposition and gene expression analyses were conducted. Results. None of the variables assessed affected cell viability, metabolic activity and proliferation. Surface topography was found to be a potent regulator of cell morphology. Macromolecular crowding significantly increased extracellular matrix deposition, albeit in globular manner independently on whether grooved or planar substrates were used, possibly due to the low dimensionality of the grooves. Gene expression analysis made apparent that the 130 kPa and the 1,000 kPa grooved substrates under macromolecular crowding conditions maintained human tenocyte phenotype and directed human bone marrow mesenchymal stromal cells towards tendon-like lineage, respectively. None of the conditions assessed dramatically affected human skin fibroblast fate. Conclusions. Collectively, our data indicate that the physicochemical in vitro microenvironment modulators assessed herein are capable of maintaining human tenocyte phenotype and differentiating human bone marrow mesenchymal stromal cells towards tenogenic lineage, but not in trans-differentiating human skin fibroblasts

Introduction. The incidences of fragility fractures, often because of osteoporosis, are increasing. Research has moved towards bioresorbable scaffolds that provide temporary mechanical stability and promote osteogenesis. This research aims to fabricate a 3D printed composite Poly (l-lactic-co-glycolic acid)-strontium doped tricalcium phosphate (PLGA-SrTCP) scaffold and evaluate in an in vitro co culture study containing osteoporotic donor cells. Method. PLGA, PLGA TCP, and PLGA SrTCP scaffolds were produced using Fused Filament Fabrication (FFF). A four-group 35-day cell culture study was carried out using human bone marrow derived mesenchymal stem cells (hMSCs) from osteoporotic and control donors (monoculture) and hMSCs & human monocytes (hMCs) (Co culture). Outcome measures were biochemical assays, PCR, and cell imaging. Cells were cultured on scaffolds that had been pre-degraded for six weeks at 47°C prior to drying and gamma sterilisation. Result. 3D printed scaffolds were successfully produced by FFF. All groups in the study supported cell attachment onto the scaffolds, producing extracellular matrices as well as evidence of osteoclast cell structures. Osteoporotic cells increased CTSK activity and CAII activity and decreased ALP activity compared to controls. In control cultures, the addition of bTCP and bTCP/Sr to the PLGA reduced TRAP5b, CAII and ALP activity compared to PLGA alone. The addition of Sr did not show any differences between donors. Conclusion. This study details suitability of 3D printed polymer scaffolds for use in bone tissue applications. Both composite and pure polymer scaffolds promote osteogenesis in vitro. The introduction of ceramic filler and ion doping does not beneficially effect osteogenic potential and can reduce its ability compared to pure polymer. This study suggests the behaviour of control and osteoporotic cells are different and that osteoporotic cells are more prone to bone resorption. Therefore, it is important to design bone scaffolds that are specific to the patient as well as to the region of fracture

Aims

The incidence of limb fractures in patients living with HIV (PLWH) is increasing. However, due to their immunodeficiency status, the operation and rehabilitation of these patients present unique challenges. Currently, it is urgent to establish a standardized perioperative rehabilitation plan based on the concept of enhanced recovery after surgery (ERAS). This study aimed to validate the effectiveness of ERAS in the perioperative period of PLWH with limb fractures.

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The aim of this study was to compare patient-reported outcomes (PROMs) following isolated anterior cruciate ligament reconstruction (ACLR), with those following ACLR and concomitant meniscal resection or repair.

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This study aimed to define the histopathology of degenerated humeral head cartilage and synovial inflammation of the glenohumeral joint in patients with omarthrosis (OmA) and cuff tear arthropathy (CTA). Additionally, the potential of immunohistochemical tissue biomarkers in reflecting the degeneration status of humeral head cartilage was evaluated.

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This study examined the relationship between obesity (OB) and osteoporosis (OP), aiming to identify shared genetic markers and molecular mechanisms to facilitate the development of therapies that target both conditions simultaneously.

Aims. This study aimed to demonstrate the promoting effect of elastic fixation on fracture, and further explore its mechanism at the gene and protein expression levels. Methods. A closed tibial fracture model was established using 12 male Japanese white rabbits, and divided into elastic and stiff fixation groups based on different fixation methods. Two weeks after the operation, a radiograph and pathological examination of callus tissue were used to evaluate fracture healing. Then, the differentially expressed proteins (DEPs) were examined in the callus using proteomics. Finally, in vitro cell experiments were conducted to investigate hub proteins involved in this process. Results. Mean callus volume was larger in the elastic fixation group (1,755 mm. 3. (standard error of the mean (SEM) 297)) than in the stiff fixation group (258 mm. 3. (SEM 65)). Pathological observation found that the expression levels of osterix (OSX), collagen, type I, alpha 1 (COL1α1), and alkaline phosphatase (ALP) in the callus of the elastic fixation group were higher than those of the stiff fixation group. The protein sequence of the callus revealed 199 DEPs, 124 of which were highly expressed in the elastic fixation group. In the in vitro study, it was observed that a stress of 200 g led to upregulation of thrombospondin 1 (THBS1) and osteoglycin (OGN) expression in bone marrow mesenchymal stem cells (BMSCs). Additionally, these genes were found to be upregulated during the osteogenic differentiation process of the BMSCs. Conclusion. Elastic fixation can promote fracture healing and osteoblast differentiation in callus, and the ability of elastic fixation to promote osteogenic differentiation of BMSCs may be achieved by upregulating genes such as THBS1 and OGN. Cite this article: Bone Joint Res 2024;13(10):559–572

The October 2024 Knee Roundup³⁶⁰ looks at: Managing the unexpected: treatment of intraoperative medial collateral ligament injuries; Identifying subgroups of patients that may benefit from robotic arm-assisted total knee arthroplasty: secondary analysis of data from a randomized controlled trial; Cost-effectiveness of enoxaparin versus aspirin in the prevention of venous thromboembolism after total hip or knee arthroplasty: an analysis from the CRISTAL cluster-randomized trial; Cartilage regeneration and long-term survival in medial knee osteoarthritis patients treated with high tibial osteotomy and osteochondral autologous transfer system; Treatment of chronic and complex meniscal tears with arthroscopic meniscus repair augmented with collagen matrix wrapping: failure rate and functional outcomes; Long-term outcomes of multiligament knee injuries in American football players.

Bone regeneration and repair are crucial to ambulation and quality of life. Factors such as poor general health, serious medical comorbidities, chronic inflammation, and ageing can lead to delayed healing and nonunion of fractures, and persistent bone defects. Bioengineering strategies to heal bone often involve grafting of autologous bone marrow aspirate concentrate (BMAC) or mesenchymal stem cells (MSCs) with biocompatible scaffolds. While BMAC shows promise, variability in its efficacy exists due to discrepancies in MSC concentration and robustness, and immune cell composition. Understanding the mechanisms by which macrophages and lymphocytes – the main cellular components in BMAC – interact with MSCs could suggest novel strategies to enhance bone healing. Macrophages are polarized into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes, and influence cell metabolism and tissue regeneration via the secretion of cytokines and other factors. T cells, especially helper T1 (Th1) and Th17, promote inflammation and osteoclastogenesis, whereas Th2 and regulatory T (Treg) cells have anti-inflammatory pro-reconstructive effects, thereby supporting osteogenesis. Crosstalk among macrophages, T cells, and MSCs affects the bone microenvironment and regulates the local immune response. Manipulating the proportion and interactions of these cells presents an opportunity to alter the local regenerative capacity of bone, which potentially could enhance clinical outcomes.

Cite this article: Bone Joint Res 2024;13(9):462–473.

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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 osteoblast and osteoclast differentiation.

Rotator cuff tears are common in middle-aged and elderly patients. Despite advances in the surgical repair of rotator cuff tears, the rates of recurrent tear remain high. This may be due to the complexity of the tendons of the rotator cuff, which contributes to an inherently hostile healing environment. During the past 20 years, there has been an increased interest in the use of biologics to complement the healing environment in the shoulder, in order to improve rotator cuff healing and reduce the rate of recurrent tears. The aim of this review is to provide a summary of the current evidence for the use of forms of biological augmentation when repairing rotator cuff tears.

Cite this article: Bone Joint J 2024;106-B(9):978–985.

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To explore the efficacy of extracorporeal shockwave therapy (ESWT) in the treatment of osteochondral defect (OCD), and its effects on the levels of transforming growth factor (TGF)-β, bone morphogenetic protein (BMP)-2, -3, -4, -5, and -7 in terms of cartilage and bone regeneration.