An increased number of neutrophils (NEUs) has long been associated with infections in the knee joints; their contribution to knee osteoarthritis (KOA)
In approximately 20 years, surgical treatment of femoro-acetabular impingement (FAI) has been widely accepted, and its indications refined. However, the current approach of the disease prevents a good understanding of its
Intervertebral disc (IVD) degeneration is one of the major contributors to low back pain, the leading cause of disability worldwide. This multifactorial pathological process involves the degradation of the extracellular matrix, inflammation, and cell loss due to apoptosis and senescence. While the deterioration of the extracellular matrix and cell loss lead to structural collapse of the IVD, increased levels of inflammation result in innervation and the development of pain. Amongst the known regulators of inflammation, toll-like receptors (TLRs) and more specifically TLR-2 have been shown to be specifically relevant in IVD degeneration. As strong post-transcriptional regulators, microRNAs (miRNAs) and their dysregulation has been connected to multiple pathologies, including degenerative diseases such as osteoarthritis and IVD degeneration. However, the role of miRNAs in TLR signalling in the IVD is still poorly understood and was hence investigated in this study. Human Nucleus pulposus (hNP) and Annulus fibrosus (hAF) cells (n=5) were treated with the TLR-2/6 specific agonist PAM2CSK4 (100 ng/mL for 6 hours) in order to activate the TLR2 signalling pathway. After the activation both miRNA and mRNA were isolated, followed by next-generation sequencing and qPCR analysis of proinflammatory cytokines respectively. Furthermore, cell supernatants were used to analyze the secretion of proinflammatory cytokines with enzyme-linked immunosorbent assay. TLR-2 knockdown (siRNA) cells were used as a control. Statistical analysis was conducted by performing Kolmogorov-Smirnov test and a two-tailed Student's t-test using GraphPad Prism version 9.0.2 for Windows (GraphPad Software, La Jolla California USA).Introduction and Objective
Materials and Methods
The paramount importance of synovial fluid in lubrication and protection of articular joints has long been recognized. Synovial fluid, a dialysate of plasma, forms an interface with both the synovium and cartilage and plays a crucial role in joint lubrication and bearing functions. In an osteoarthritic joint, damage to the articular cartilage causes modifications in the rheological properties of synovial fluid and, reducing the viscoelasticity and increasing the friction between articular surfaces. Viscosupplementation is a treatment for osteoarthritis that uses hyaluronic acid as a (visco)supplement to the diseased joint. The aim of this treatment is to restore the rheological properties of synovial fluid. Osteoarthritis is the most common disease affecting the joints in human population and among the most important causes of pain, disability and economic loss. Therefore, innovative methods are needed to more effectively treat osteoarthritis, directly addressing the disease process. Among various locomotor mechanisms that could serve to illustrate the integrated nature of functional morphology, perhaps none is more complex than the equine locomotor system. Confronting the need for evaluating the current methods to control joint disease, the horse provides an excellent animal model. As it suffers similar clinical manifestations to those seen in human, it may provide tentative biomedical extrapolations.
Vascular inflammation and activation of myofibroblasts are significant contributors to the progression of fibrosis, which can severely impair tissue function. In various tissues, including tendons, Transforming growth factor beta 1 (TGF-β1) has been identified as a critical driver of adhesion and scar formation. Nevertheless, the mechanisms that underlie fibrotic peritendinous adhesions are still not well comprehended, and human microphysiological systems to help identify effective therapies remain scarce. To address this issue, we developed a novel human Tendon-on-a-Chip (hToC), comprised of an endothelialized vascular compartment harboring circulating monocytes and separated by a 5 μm/100 nm dual-scale ultrathin porous membrane from a type I/III collagen hydrogel with primary tendon fibroblasts and tissue-resident macrophages, all under defined serum-free conditions. The hToC models the crosstalk of the various cells in the system leading to the induction of inflammatory and fibrotic pathways including the activation of mTOR signaling. Consistent with phenotypes observed in vivo in mouse models and clinical human samples, we observed myofibroblast differentiation and senescence, tissue contraction, excessive extracellular matrix deposition, and monocytes’ transmigration and macrophages’ secretion of inflammatory cytokines, which were dependent on the presence of the endothelial barrier. This model offers novel insights on the role of vasculature in the
Imaging can provide valuable information about the function of tissues and organs. The capacity for detecting and measuring imaging biomarkers of biological activities, allows for a better understanding of the
The pathophysiological basis of alterations in trabecular bone of patients with osteonecrosis of the femoral head (ONFH) remains unclear. ONFH has classically been considered a vascular disease with secondary changes in the subchondral bone. However, there is increasing evidence suggesting that ONFH could be a bone disease, since alterations in the functionality of bone tissue distant from the necrotic lesion have been observed. We comparatively studied the transcriptomic profile of trabecular bone obtained from the intertrochanteric region of patients with ONFH without an obvious aetiological factor, and patients with osteoarthritis (OA) undergoing total hip replacement in our Institution. To explore the biological processes that could be affected by ONFH, we compared the transcriptomic profile of trabecular bone from the intertrochanteric region and the femoral head of patients affected by this condition. Differential gene expression was studied using an Affymetrix microarray platform. Transcriptome analysis showed a differential signature in trabecular bone from the intertrochanteric region between patients with ONFH and those with OA. The gene ontology analyses of the genes overexpressed in bone tissue of patients with ONFH revealed a range of enriched biological processes related to cell adhesion and migration and angiogenesis. In contrast, most downregulated transcripts were involved in cell division. Trabecular bone in the intertrochanteric region and in the femoral head also exhibited a differential expression profile. Among the genes differentially expressed, we highlighted those related with cytokine production and immune response. This study identified a set of differently expressed genes in trabecular bone of patients with idiopathic ONFH, which might underlie the
In the past decades, a huge amount of effort has been devoted to translate evidence based on standard preclinical models of bone tumours to effective tools for clinical applications. Although cancer is a genetic disease, hence the emphasis on -omics approaches, the complexity of cancer tissue, a mix of competing clones of transformed elements that react differently to microenvironmental stimuli, may hardly be reproduced by standard approaches. Cost, biological differences and ethical concerns are increasingly recognized as weaknessess of animal models. To overcome these limitations and provide reliable, reproducible, and affordable tools for predicting the effectiveness of treatments, environmental-controlled 3D cultures and co-cultures (spheroids, organoids) coupled with microfluidics and advanced imaging have recently being considered as effective instrument to increase knowledge on the
Breast cancer is the most frequent malignancy in women with an estimation of 2.1 million new diagnoses in 2018. Even though primary tumours are usually efficiently removed by surgery, 20–40% of patients will develop metastases in distant organs. Bone is one of the most frequent site of metastases from advanced breast cancer, accounting from 55 to 58% of all metastases. Currently, none of the therapeutic strategies used to manage breast cancer bone metastasis are really curative. Tailoring a suitable model to study and evaluate the disease
OA
While knee osteoarthritis (OA) is now recognized as a complex disease affecting the whole joint, not just the cartilages, there remains a paucity of data regarding the interactions between knee components. One relationship of particular interest is between the spatial variations in cartilage thickness (CTh) and subchondral bone mineral density (BMD). Indeed, bone and cartilage are two mechanosensitive tissues that interact as a functional unit and there is evidence of a biomechanical coupling between both tissues. Particularly, a recent in vivo study has shown a positive relationship in non-OA knees with thicker cartilage where bone is denser, and an alteration of this relationship in OA knees. These observations support the concept of an osteochondral unit and warrant additional research to assess the influence of bone depth. Therefore, this study aimed to characterize the relationship between spatial variations in CTh and BMD measured at various depths below the bone surface. CT-arthrography of 20 non-OA tibias and 20 severe medial-compartment OA tibias were segmented to build 3D mesh models of the bones and cartilages. Each individual tibia model was registered to a reference tibia, allowing to calculate BMD maps at 1, 3, 5 and 10mm below the bone-cartilage interface in the medial compartment. Pearson correlations between CTh maps and the four BMD maps were then calculated for each knee. Lastly, differences in correlation coefficients between successive bone layers were assessed using Wilcoxon signed-rank tests. In both OA and non-OA tibias, the correlation coefficients were higher with the BMD measured in the 1mm layer, and followed a pattern of statistically significant decrease with bone layers of increasing depth (p < 0.021). In non-OA tibias, the median relationship was positive with a strong effect size in the 1, 3 and 5mm layers, while in OA tibias the median relationship was positive only in the 1mm layer and with a medium effect size. In the OA tibias, the median relationship was negative with a weak effect size in the 3 and 5mm layers, and it was negative with a medium effect size in the 10mm layer. In conclusion, the results of the present study support the value of considering bone and cartilage as a unit, and more generally support OA
Spinal cord injury (SCI) is a devastating disorder for which the identification of exacerbating factors is urgently needed. Although age, blood pressure and infection are each considered to be prognostic factors in patients with SCI, exacerbating factors that are amenable to treatment remain to be elucidated. Microglial cells, the resident immune cell in the CNS, form the first line of defense after being stimulated by exposure to invading pathogens or tissue injury. Immediately after SCI, activated microglia enhance and propagate the subsequent inflammatory response by expressing cytokines, such as TNF-α, IL-6 and IL-1β. Recently, we demonstrated that the activation of microglia is associated with the neuropathological outcomes of SCI. Although the precise mechanisms of microglial activation remain elusive, several basic research studies have reported that hyperglycemia is involved in the activation of resident monocytic cells, including microglia. Because microglial activation is associated with secondary injury after SCI, we hypothesized that hyperglycemia may also influence the
Human in vitro models of the neuromuscular junction (NMJ) are currently moving from embryonic stem cells to induced Pluripotent Stem Cells (iPSCs). With this, a robust model could be optimised for physiology and
Appropriate in vivo models can be used to understand atrophic non-union
Complex
Dynamic loading is necessary for the preservation of native cartilage, but mechanical disuse is one major risk factor for osteoarthritis (OA). As post-transcriptional regulators, microRNAs (miRs) represent promising molecules to quickly adjust the cellular transcriptome in a stimulus-dependent manner. Several miR clusters were related to skeletal development, joint homeostasis and OA
Synovitis has been shown to play a role in
Ligaments and tendons are vital musculoskeletal soft tissues, which are commonly injured due to overuse and trauma. Their distinct functions are well known however their unique structure and biochemical composition and how they change with disease is poorly described. The most commonly injured ligament in the dog and man is the cranial cruciate (CCL) and anterior cruciate ligament (ACL) respectively. Therefore, the structure, function and
Confirming clinical evidence, we recently demonstrated in a rodent model that a severe trauma which induces an acute systemic inflammation considerably impairs fracture healing. Interleukin-6 (IL-6) is a key cytokine in posttraumatic inflammation as its serum level correlates with injury severity and mortality. IL-6 signals are transmitted by the transmembrane glycoprotein 130 (gp130) via two distinct mechanisms: firstly, through classic signalling via the membrane-anchored IL-6 receptor and secondly, through trans-signalling using a soluble IL-6 receptor. Whereas IL-6 trans-signalling is considered a danger signal driving inflammation, classic signalling may mediate anti-inflammatory, pro-regenerative processes. The role of the two distinct pathways in bone healing has not yet been elucidated. Here, we studied the function of IL-6 in the
In vivo animal experimentation has been one of the cornerstones of biological and biomedical research, particularly in the field of clinical medicine and pharmaceuticals. The conventional in vivo model system is invariably associated with high production costs and strict ethical considerations. These limitations led to the evolution of an ex vivo model system which partially or completely surmounted some of the constraints faced in an in vivo model system. The ex vivo rodent bone culture system has been used to elucidate the understanding of skeletal physiology and