New Proteins Contributing to Immune Cell Infiltration and Pannus Formation of Synovial Membrane from Arthritis Diseases

An inflamed synovial membrane plays a major role in joint destruction and is characterized by immune cells infiltration and fibroblast proliferation. This proteomic study considers the inflammatory process at the molecular level by analyzing synovial biopsies presenting a histological inflammatory continuum throughout different arthritis joint diseases. Knee synovial biopsies were obtained from osteoarthritis (OA; n = 9), chronic pyrophosphate arthropathy (CPPA; n = 7) or rheumatoid arthritis (RA; n = 8) patients. The histological inflammatory score was determined using a semi-quantitative scale based on synovial hyperplasia, lymphocytes, plasmocytes, neutrophils and macrophages infiltration. Proteomic analysis was performed by liquid chromatography-mass spectrometry (LC-MS/MS). Differentially expressed proteins were confirmed by immunohistochemistry. Out of the 1871 proteins identified and quantified by LC-MS/MS, 10 proteins (LAP3, MANF, LCP1, CTSZ, PTPRC, DNAJB11, EML4, SCARA5, EIF3K, C1orf123) were differentially expressed in the synovial membrane of at least one of the three disease groups (RA, OA and CPPA). Significant increased expression of the seven first proteins was detected in RA and correlated to the histological inflammatory score. Proteomics is therefore a powerful tool that provides a molecular pattern to the classical histology usually applied for synovitis characterization. Except for LCP1, CTSZ and PTPRC, all proteins have never been described in human synovitis.

Encapsulated Allogeneic Synovial Membrane Mesenchymal Stem Cells Provide Better Outcomes of Chondral Lesions in Horses

Osteoarthritis is the main cause of equine lameness, and its treatment remains ineffective. Synovial membrane mesenchymal stem cells (SMMSCs) provide satisfactory outcomes in joint injuries, mainly due to their immunomodulatory and reparative properties. This study aimed to evaluate the effect of SMMSCs, either encapsulated in alginate hydrogel or free, in chondral lesions of horses.Methods: Chondral lesions were surgically induced in the medial trochlea of the talus of fifteen horses. Animals were treated with PBS free SMMSCs or encapsulated SMMSCs. Physical evaluations, assignment of lameness scores and synovial fluid analysis were performed (cytological analysis and dosage of IL-1, IL-10, IL-6, INF-Ɣ, TNF 𝛼, P substance, serum amyloid A, TGF-β, IGF and PGE2) for two weeks. Cartilage biopsies were performed 150 days after induction for histological analysis and immunohistochemistry staining.Results: All groups initially presented inflammation. Although free SMMSCs showed moderate tissue repair, encapsulated SMMSCs had a lower grade of inflammation with superior tissue macro- and microscopic aspects at the end, while the control group showed fibrosis and poor cartilage aspect. This study suggests better effectiveness of stem cells in chondral defects when encapsulated MSCs are used.Conclusion: While the absence of treatment perpetuates cartilage degradation, encapsulated SMMSCs respond better to initial inflammation, interacting and modulating the environment through the release of anti-inflammatory cytokines. Better outcomes observed in encapsulated MSCs were related to the immuno- and physical barriers provided by the alginate hydrogel, allowing a longer period of permanence and interaction between MSCs and the environment.

Synovial chondromatosis of the foot: A case report with brief review

Synovial chondromatosis is a rare, benign disorder which commonly involves the large joints and is characterised by the proliferation of cartilaginous nodules beneath the synovial membrane. We report a case of an elderly male who presented with pain and swelling of the right foot since five years. Proper clinico- radiological and histological evaluation of this case led to the diagnosis of synovial chondromatosis which was managed surgically and patient’s symptoms were relieved. The rare occurrence of this entity in the small joints of hands and feet and the presence of several close differentials, warrants a thorough clinico-radiological and histological work-up to prevent unnecessary surgical exploration.

Morphological changes in the tissues of the knee joints of rats in carrageenan-induced experimental arthritis

Every fifth inhabitant of the earth has been diagnosed with osteoarthritis of various etiologies. Morphological studies of arthritis provide a theoretical basis for creating optimal treatments for this pathology. Given the polyetiological nature of the disease, the choice of the optimal experimental model, which would be as close as possible to the real conditions of inflammatory process reproduction, is the topical issue. The purpose of the study was to confirm the pathological reaction of the joint tissues of laboratory animals in response to intraperitoneal administration of ƛ-carrageenan. The study was performed on 50 white Wistar rats males aged 12 weeks, weighing 130-150 g. The animals were euthanized by an overdose of anaesthesia according to the terms of the study (1 - 30 days). Fragments of the distal metaepiphyses of the femur and proximal metaepiphyses of the tibia were used for histological examination. Staining of sections obtained on the microtome was performed with haematoxylin, eosin, and Van Gieson`s stain. From the first day of the experimental study, a corresponding reaction of the joint tissues was being observed. Particularly pronounced were the changes in the synovial membrane in the form of oedema of the villi accompanied by an increased filling of blood vessels with foci of thrombosis. Gradually, up to 5 days in the synovial membrane, proliferative changes took place with a clear definition of the multilineage of the integumentary layer, vascular reaction with a tendency to thrombosis, in some places necrosis of synoviocytes was observed, but relative integrity of the morphological structure was still provided by protective barriers of bone and cartilage. On the 7th day pronounced resorption of both bone and cartilage tissue occurred, tissue structure became disorganized and functional layer became thin, accompanied by massive intracellular lysis. The process of synoviocytes necrobiosis with fatty degeneration spread. The histological picture of 10 days is characterized by generalized destruction of bone beams; the destroyed cartilage was replaced by granulation tissue with the presence of cavities. Massive foci of lymphocytic infiltration were observed in the synovial membrane. On the 14th day, a fragmentation of cartilage happened, most of the bone beams (trabeculae) were destroyed. After 3 weeks the morphological picture of cartilage tissue was determined by the appearance in the lacunae of viable cells, the number of which was close to normal. Bone beams were restored, although they remained thin. In a synovial membrane, the hyperplasia of apical departments of villi, leukocytes infiltration, disorganization of connective tissue, and separate vascular disturbances remained. 30 days of the experiment were characterized by a relative recovery of structural relationships to normal. The obtained data confirm the feasibility of using carrageenan in experimental studies of osteoarthritis.

Device-Based Enrichment of Knee Joint Synovial Cells to Drive MSC Chondrogenesis Without Prior Culture Expansion In Vitro: A Step Closer to 1-Stage Orthopaedic Procedures

Background: Synovial fluid (SF) mesenchymal stem cells (MSCs) are derived from the synovial membrane and have cartilage repair potential. Their current use in clinical practice is largely exploratory. As their numbers tend to be small, therapeutic procedures using MSCs typically require culture expansion. Previous reports indicate that the stem cell–mobilizing device (STEM device) intraoperatively increases SF-MSCs. Purpose: This study evaluated the chondrogenic potential of non–culture expanded synovium-mobilized MSCs and SF-microfragments obtained after enrichment using the STEM device and ascertained if device-mediated synovial membrane manipulation facilitated ongoing MSC release. Study Design: Controlled laboratory study. Methods: Two samples of aspiration fluid were collected intraoperatively before and after STEM device utilization from patients (n = 16) undergoing diagnostic or therapeutic knee arthroscopy. Human knee synovium (n = 5) was collected during total knee replacement, and a suspended culture was performed to assess the effect of the STEM device on ongoing MSC release. Colony forming unit–fibroblastic assays were used to determine the number of MSCs. Additionally, cytometric characterization of stromal and immune cells and chondrogenesis differentiation assay were performed without culture expansion. Filtered platelet concentrates were prepared using the HemaTrate system. Results: After STEM device use, a significant increase was evident in SF-MSCs ( P = .03) and synovial fluid–resident synovial tissue microfragments ( P = .03). In vitro–suspended synovium released significantly more MSCs following STEM device use than nonstimulated synovium ( P = .01). The STEM device–released total cellular fraction produced greater in vitro chondrogenesis with significantly more glycosaminoglycans (GAGs; P < .0001) when compared with non–STEM device synovial fluid material. Nonexpanded SF-MSCs and SF-microfragments combined with autologous filtered platelet concentrate produced significantly more GAGs than the complete chondrogenic media ( P < .0001). The STEM device–mobilized cells contained more M2 macrophage cells and fewer M1 cells. Conclusion: Non–culture expanded SF-MSCs and SF-microfragments had the potential to undergo chondrogenesis without culture expansion, which can be augmented using the STEM device with increased MSC release from manipulated synovium for several days. Although preliminary, these findings offer proof of concept toward manipulation of the knee joint environment to facilitate endogenous repair responses. Clinical Relevance: Although numbers were small, this study highlights 3 factors relevant to 1-stage joint repair using the STEM device: increased SF-MSCs and SF-microfragments and prolonged synovial release of MSCs. Joint repair strategies involving endogenous MSCs for cartilage repair without the need for culture expansion in a 1-stage procedure may be possible.

Therapeutic Role of Platelet Rich Plasma in Formaldehyde-Induced Arthritis in Adult Male Albino Rats

Introduction Osteoarthritis (OA) is a common health problem. Platelet-rich plasma (PRP) has been recognized to enhance articular cartilage metabolism. Aim of the work the study was designed to investigate the influence of PRP on cartilage healing after induction of arthritis. Material and methods Forty two adult male albino rats were used in this study. The rats were randomly divided into three groups: Group I (n = 18): the control group (Ia, Ib & Ic) Ib & Ic were injected intra-articularly with saline and left for 3 and 6 weeks. Group II (n = 12): arthritic group, in which osteoarthritis was induced by injection of 0.02ml 5% formaldehyde once in the right knee joints, left without treatment, and were sacrificed after three weeks (IIa) or after six weeks (IIb). Group III(n = 12): arthritis was induced as group II, one week later, the rats were intra-articularly injected with single dose of 0.3ml PRP in the same joint then were sacrificed three weeks (IIIa) or six weeks (IIIb) after formaldehyde injection. At the end of the study the right knee joints were taken, decalcified then processed for paraffin sections to be examined by light microscope using H&E, toluidine blue and Masson’s trichrome (MTC) stains. Immunohistochemistry for caspase-3 enzyme was done to demonstrate apoptotic chondrocytes. Morphometric study was conducted to measure the thickness of the non-calcified cartilage, count the chondrocytes and synovial membrane inflammatory cells and Mankin's score. Then statistical analysis was done. Results The arthritic groups revealed irregular surface of the articular cartilage, loss of the articular matrix and bone eburnation. Moreover, there was apparent hypocellularity and disorganization of the chondrocytes. Osteoclasts and osteoblasts were seen invading the osteochondral junction. MTC stained sections of the synovial membrane showed deposition of thick collagen bundles with heavy inflammatory cell infiltrate and numerous blood vessels. The affinity of the articular cartilage to toluidine blue stain was apparently decreased while caspase-3 immunoreactivity was apparent in many chondrocytes .Group IIIa demonstrated almost similar histological findings as the control group; regular articular cartilage surface with regularly arranged chondrocytes in the different cartilage zones. Synovial membrane illustrated minimal inflammatory cell infiltrate with thin collagen bundles and small blood vessels in MTC stained sections. There was high affinity of the articular cartilage to the toluidine blue stain and few chondrocytes showed positive caspase-3 immunoreactivity. Group IIIb revealed continuous surface of the articular cartilage, yet with minimal fibrillation in some areas. Osteoblasts and osteoclasts were seen invading the calcified cartilage. Synovial membrane showed deposition of dense collagen bundles with some inflammatory cell infiltrate. Toluidine blue sections revealed decreased articular cartilage affinity to the stain while caspase-3 immunoreactivity was evident in many chondrocytes. The morphometric results and statistical analysis confirmed the histological findings. Conclusion Intra-articular injection of PRP demonstrated advantageous role on articular cartilage healing, however, these effects appeared to be transient. So the need of multiple injections of PRP has to be considered in cases of OA.

Biofilm Formation by Pseudomonas aeruginosa in a Novel Septic Arthritis Model

BackgroundBacterial biofilms generally contribute to chronic infections and complicate effective treatment outcomes. To date, there have been no reports describing biofilm formation in animal models of septic arthritis caused by Pseudomonas aeruginosa (P. aeruginosa). P. aeruginosa is an opportunistic pathogenic bacterium which can lead to septic arthritis. The purpose of this study was to establish a rabbit model of septic arthritis caused by P. aeruginosa to determine whether it leads to biofilm formation in the knee joint cavity. In addition, we explored the role of cyclic di-GMP (c-di-GMP) concentrations in biofilm formation in rabbit models.MethodsTwenty rabbits were randomly assigned to five groups: PAO1 (n = 4), PAO1ΔwspF (n = 4), PAO1/plac-yhjH (n = 4) infection group, Luria–Bertani (LB) broth (n = 4), and magnesium tetrasilicate (talc) (n = 4) control groups. Inoculation in the rabbit knee of P. aeruginosa or with the same volume of sterile LB or talc in suspension (control group) was used to induce septic arthritis in the animal model. In the infection groups, septic arthritis was caused by PAO1, PAO1ΔwspF, and PAO1/plac-yhjH strains, respectively. Rabbits were euthanized after 7 days, and pathological examination of synovial membrane was performed. The biofilms on the surface of the synovial membrane were observed by scanning electron microscopy, while the biofilms’ fiber deposition was discriminated using peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH).ResultsA rabbit model for knee septic arthritis induced by P. aeruginosa was successfully established. Scanning electron microscopy revealed that PAO1 strains were surrounded in a self-produced extracellular matrix on the surface of synovial membrane and showed biofilm structures. The biofilms in the fibrous deposition were also observed by PNA-FISH. The PNA-FISH assay revealed that the red fluorescence size in the PAO1ΔwspF group was greater than in PAO1 and PAO1/plac-yhjH groups.ConclusionsThis is the first study to provide evidence that P. aeruginosa forms biofilms in a rabbit model for septic knee arthritis. The rabbit model can be used to investigate new approaches to treatment of biofilms in septic arthritis. Furthermore, c-di-GMP is a key signaling molecule which impacts on biofilm formation in rabbit models of knee septic arthritis.

CONTEMPORARY UNDERSTANDING OF THE PATHOGENESIS OF RHEUMATOID ARTHRITIS.

Rheumatoid Arthritis (RA) is one of the most common rheumatologic conditions. Dell et al (2013) denes RA as a systemic autoimmune polyarticular arthritis, which can also have extra-articular manifestations that can lead to various systemic complications,. It is more common in women and can present at any age, however, the peak age of onset is the fth decade. RA mainly involves the synovial membrane leading to synovial inammation, proliferation, pannus formation and destruction of the articular cartilage, peri- articular bone and soft tissues.