Late-stage Osteoarthritis Research Articles

Surgically induced degenerative changes in the femorotibial joints by total medial meniscectomy in minipigs closely resemble late-stage osteoarthritis

Surgically induced degenerative changes in the femorotibial joints by total medial meniscectomy in minipigs closely resemble late-stage osteoarthritis

Morphological and ultrastructural analysis of normal, injured and osteoarthritic human knee menisci.

The human meniscus plays a crucial role for transmission and distribution of load across the knee, as well as shock absorption, joint stability, lubrication, and congruity. The aim of this study was to compare the complex geometry, and unique ultrastructure and tissue composition of the meniscus in healthy (control) and pathological conditions to provide understanding of structural changes that could be helpful in the future design of targetted therapies and improvement of treatment indications. We analyzed meniscus samples collected from 3 healthy multi-organ donors (median age, 66 years), 5 patients with traumatic meniscal tear (median age, 41 years) and 3 patients undergoing total knee replacement (TKR) for end-stage osteoarthritis (OA) (median age, 72 years). We evaluated the extracellular matrix (ECM) organization, the appearance and distribution of areas of calcification, and modifications of cellular organization and structure by electron microscopy and histology. The ECM structure was similar in specimens from traumatic meniscus tears compared to those from patients with late-stage OA, showing disorganization of collagen fibers and increased proteoglycan content. Cells of healthy menisci showed mainly diffuse chromatin and well preserved organelles. Both in traumatic and in OA menisci, we observed increased chromatin condensation, organelle degeneration, and cytoplasmic vacuolization, a portion of which contained markers of autophagic vacuoles. Areas of calcification were also observed in both traumatic and OA menisci, as well as apoptotic- like features that were particularly prominent in traumatic meniscal tear samples. We conclude that meniscal tissue from patients with traumatic meniscal injury demonstrate pathological alterations characteristic of tissue from older patients undergoing TKR, suggesting that they have high susceptibility to develop OA.

Chitosan/hyaluronic acid/plasmid-DNA nanoparticles encoding interleukin-1 receptor antagonist attenuate inflammation in synoviocytes induced by interleukin-1 beta

Synovial inflammation mainly resulting from interleukin-1 beta (IL-1β) plays a crucial role in the early and late stage of osteoarthritis. Recent progress in therapeutic gene delivery systems has led to promising strategies for local sustained target gene expression. The aim of this study was to design a nanoparticle made of chitosan (CS)/hyaluronic acid (HA)/plasmid-DNA (pDNA) encoding IL-1 receptor antagonist gene (pIL-1Ra) and furtherly use it to transfect the primary synoviocytes, and then investigate whether CS/HA/pIL-1Ra nanoparticles could make the synoviocytes overexpress functional IL-1Ra to attenuate inflammation induced by IL-1β. In this study, CS was modified with HA to generate CS/HA nanoparticles and then combined with pIL-1Ra to form CS/HA/pIL-1Ra nanoparticles. The physicochemical characteristics results showed that CS/HA nanoparticles exhibited an appropriate particle size (144.9 ± 2.8 nm) and positive zeta potential ( + 28 mV). The gel retardation assay revealed that pDNA was effectively protected and released in a sustained manner more than 15 days. Cytotoxicity results showed that CS/HA/pIL-1Ra nanoparticles had a safe range (0-80 μg/ml) for the application to synoviocytes. RT-qPCR and western blot analysis demonstrated that CS/HA/pIL-1Ra nanoparticles were able to increase IL-1Ra expression in primary synoviocytes, and reduce the mRNA and protein levels of matrix metalloproteinase-3 (MMP-3), matrix metalloproteinase-13 (MMP-13), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in IL-1β-induced synoviocytes. Our findings indicated that CS/HA/pIL-1Ra nanoparticles efficiently transfected synoviocytes and attenuated synovitis induced by IL-1β, which will provide a potential strategy for OA synovitis.

Diagnostic performance of knee physical exam and participant-reported symptoms for MRI-detected effusion-synovitis among participants with early or late stage knee osteoarthritis: data from the Osteoarthritis Initiative

Evaluate the diagnostic performance of knee physical exam findings and participant-reported symptoms for MRI-detected effusion-synovitis (ES) among knees with early and late-stage osteoarthritis (OA). The Osteoarthritis Initiative (OAI) is a longitudinal study of participants with or at risk for knee OA. Two samples with MRI readings were available: 344 knees with early OA (312 participants) and 216 with late-stage OA (186 participants). Trained examiners performed bulge sign (BS) and patellar tap (PT) exams, and participants reported on knee swelling and pain with leg straightening. Effusion-synovitis on 3T non-contrast MRI was scored using the MRI Osteoarthritis Knee Score (MOAKS). Diagnostic performance of physical exam findings and symptoms was estimated with bootstrapped confidence intervals. For the early OA sample, the highest sensitivity for medium/large effusion-synovitis was achieved with a positive finding for any of the physical exam maneuvers and/or participant-reported symptoms (81.0 [95% CI: 70.0, 91.3]). Both knee symptoms in combination had a prevalence of 11.7% and yielded the highest estimated positive predictive value (PPV) (50.0 [95% CI: 34.2, 66.7]) and likelihood ratio positive (LR+) (5.2 [95% CI: 2.9, 9.7]). In late-stage OA knees, exam findings and symptoms provided minimal information beyond the prevalence. Patient report of both symptoms, or at least one positive exam finding and at least one symptom, could be used to identify knees at increased risk of effusion-synovitis in knees with early stage OA, either for screening purposes in clinical evaluation, or for study sample enrichment with an inflammatory phenotype; diagnostic performance was not sufficiently high for clinical diagnostic purposes.

Synovectomy during total knee arthroplasty: a pilot single-centre randomised controlled trial

BackgroundTotal knee arthroplasty (TKA) is an effective procedure for late-stage osteoarthritis (OA) of the knee; however, up to 20% of patients remain dissatisfied. In some patients, this may be due to residual inflammation of the synovium. Our aim was to perform the first randomised controlled trial (RCT) of synovectomy during TKA for patients with macroscopically inflamed synovium. The main objectives were to assess recruitment rates, protocol adherence and outcomes relating to safety such as haemoglobin decrease and adverse events. We also collected data on patient-reported outcomes.MethodsWe performed a single-centre pilot RCT. Patients with a macroscopically inflamed synovium were randomised to receive synovectomy versus a control group that did not undergo synovectomy. We determined feasibility by measuring patient enrolment, completeness of follow-up, and safety via haemoglobin decrease and documentation of adverse events.ResultsWe screened 360 patients with 260 deemed ineligible or could not be recruited. From the 100 eligible patients, 54 were enrolled and 40 progressed through to randomisation. All made it to the 12-month follow-up, indicating good protocol adherence. There were no major differences in adverse events or haemoglobin decrease demonstrating acceptable safety. Outcomes relating to satisfaction were reliably obtained.ConclusionsPatients with macroscopically inflamed synovium of the knee who are due to undergo TKA can be reliably recruited to a randomised trial and synovectomy can be performed safely. A large number is needed to be screened to identify eligible participants, and therefore, a multi-centre trial would be required to assess whether routine synovectomy would improve outcomes in these patients.Trial registrationISRCTN, ISRCTN31010214. Registered 6 October 2016—retrospectively registered

Synovial fluid-derived exosomal lncRNA PCGEM1 as biomarker for the different stages of osteoarthritis.

The purpose of this study is to investigate the role of exosomal lncRNAs from plasma and from synovial fluid in patients with osteoarthritis (OA) and to determine their diagnostic value in distinguishing the early stage of OA from progressive stage of OA. Participants were divided into three groups. The control group included 20 pre-arthritic patients, early OA group included 20 patients in the early OA, and late-stage OA group included 22 patients in the late-stage OA. For all subjects, blood sample from cubital vein and synovial fluid sample from knee joint were collected. Exosomes were extracted by ultracentrifugation. LncRNAs were extracted from exosomes using RNeasy kit, and the expression of several exosomal lncRNAs, including HOTAIR, PCGEM1, and GAS5, was measured using quantitative real-time polymerase chain reaction (qPCR). Also, Spearman's correlation test was performed to determine the correlation between exosomal lncRNA PCGEM1 and WOMAC index. Last, the receiver operating characteristic (ROC) curve was performed to determine the diagnostic value of exosomal lncRNA PCGEM1 in distinguishing the different stages of OA. First, for plasma, both the expression of exosomes in three groups and the relative expression of exosomal lncRNAs chosen showed no significant difference among three groups, while for synovial fluid sample, the expression of exosomes in early OA and late-stage OA was much markedly higher than that in controls; and the expression of exosomal lncRNA PCGEM1 was markedly higher in late-stage OA than in early OA, and markedly higher in early OA than controls. Both the expression of exosomal lncRNA HOTAIR and GAS5 showed no significant difference among these groups. Second, there was a positive relationship between exosomal lncRNA PCGEM1 and WOMAC Index. Last, ROC curve showed that the area values under the curve of exosomal lncRNA PCGEM1 were 0.879, 0.757, and 0.593, respectively. Our study demonstrated that exosomal lncRNA PCGEM1 might be a powerful indicator in distinguishing the early OA from the late-stage OA.

Cell-Based Therapies for Joint Disease in Veterinary Medicine: What We Have Learned and What We Need to Know.

Biological cell-based therapies for the treatment of joint disease in veterinary patients include autologous-conditioned serum, platelet-rich plasma, and expanded or non-expanded mesenchymal stem cell products. This narrative review outlines the processing and known mechanism of action of these therapies and reviews current preclinical and clinical efficacy in joint disease in the context of the processing type and study design. The significance of variation for biological activity and consequently regulatory approval is also discussed. There is significant variation in study outcomes for canine and equine cell-based products derived from whole blood or stem cell sources such as adipose and bone marrow. Variation can be attributed to altering bio-composition due to factors including preparation technique and source. In addition, study design factors like selection of cases with early vs. late stage osteoarthritis (OA), or with intra-articular soft tissue injury, influence outcome variation. In this under-regulated field, variation raises concerns for product safety, consistency, and efficacy. Cell-based therapies used for OA meet the Food and Drug Administration’s (FDA’s) definition of a drug; however, researchers must consider their approach to veterinary cell-based research to meet future regulatory demands. This review explains the USA’s FDA guidelines as an example pathway for cell-based therapies to demonstrate safety, effectiveness, and manufacturing consistency. An understanding of the variation in production consistency, effectiveness, and regulatory concerns is essential for practitioners and researchers to determine what products are indicated for the treatment of joint disease and tactics to improve the quality of future research.

Ultrasonography of the late-stage knee osteoarthritis prior total knee arthroplasty: comparison of the ultrasonographic, radiographic and intra-operative findings

Purpose: Ultrasonography (US) of the knee is an emerging imaging technique to evaluate the osteoarthritis (OA) of the knee. To date, clinical examination followed the conventional radiographs (CR) have been deemed the gold standard for the diagnosis of the OA, but during the last decade the utility of the US on knee OA has been also studied vigorously. US can be applied to assess effusion, synovitis, osteophytes, menisci and the femoral cartilage of the knee joint. Moreover, it has been shown that US detects osteophytes more readily than CR and that the cartilage defects of the medial femoral condyle correlate well with joint-space narrowing seen on CR. The diagnostic performance of US on detecting osteoarthritic changes has been compared with magnetic resonance imaging (MRI) and arthroscopy: osteophytes, cartilage changes in the medial femoral condyle and medial meniscal extrusion can be reliably assessed by US as compared to MRI findings. Additionally, the positive findings on US are a strong indicator of arthroscopic degenerative changes; however, negative findings do not rule out osteoarthritic changes. Despite eager research, it is still unknown whether the weight-carrying joint spaces are visualized on US and how plausible the US findings are. The purpose of this study was to assess US findings on patients with late-stage knee OA undergoing total knee arthroplasty (TKA) and compare US findings to radiographic and intra-operative findings. Methods: 103 patients planned for TKA for late-stage OA of the knee were enrolled consecutively in this study during October 2016 and February 2017. The mean subject age was 69 years (range 47 to 84 years) and 36 % were males. 21 patients had bilateral TKA, so in total 124 knees were included in this study. Eventually, 57 knees underwent TKA. US of the knee was performed by a single radiologist: the presence of effusion, synovitis, osteophytes, femoral cartilage wear and meniscal pathology was documented. All patients underwent bilateral weight-bearing CR on the same day as the US examination. The knees were assessed by the same radiologist for osteophytes, joint space narrowing and KL grades. During the TKA, the corresponding intra-operative findings were documented by orthopedic surgeon. Results: When comparing the US findings with the intra-operative findings, US examination performed well. On the wearing of the cartilage of the femoral medial condyle the sensitivity, specificity, accuracy and positive predictive value were 92%, 50%, 88% and 94%, respectively. On the lateral condyle and the sulcus area, the sensitivities were 58% and 46%; the specificities were 76% and 84%; accuracies were 70% and 67%; and the positive predictive values were 55% and 71%, respectively. Concerning the evaluation of the osteophytes, the detection rate of the US was outstanding especially on the medial side: On the femoral medial condyle the sensitivity, specificity, accuracy and positive predictive value were 95%, 50%, 93% and 98%, respectively. On the femoral lateral condyle they were 93%, 27%, 75% and 78%, respectively. On the tibial medial condyle the sensitivity, specificity, accuracy and positive predictive value were 90%, 75%, 88% and 96%, respectively. On the tibial lateral condyle they were 65%, 76%, 72% and 59%, respectively. The sensitivities for detecting effusion and synovitis were also excellent, yielding a sensitivity of 97% and 97%, respectively. For the damage of the medial and lateral meniscus the sensitivities were 93% and 58%, respectively. When comparing US with CR - using the TKA findings as the gold standard – the detection rate of cartilage damage was in line with the radiographic findings: For the medial joint space, the sensitivities of the US versus CR were 92% and 92%, the specificities 50% and 67%, the accuracies 88% and 89%, and the positive predictive values were 94% and 96%. For lateral joint space, the US versus CR sensitivities were 58% and 42%, specificities 76% and 67%, accuracies 70% and 68%, and the positive predictive values 55% and 53%. On the detection of the osteophytes, US provided superior results to CR especially on the medial side: On the femoral medial condyle, the US versus CR sensitivities were 95% and 44%; on the femoral lateral condyle 93% and 24%; on the tibial medial condyle 90% and 76%; and on the tibial lateral condyle 65% and 70%, respectively. Conclusions: US can reliably assess the late-stage OA changes of the knee especially on the medial side. Our study shows excellent sensitivities for effusion, synovitis, osteophytes, cartilage damage and meniscal pathology. Furthermore, US yields superior detection of OA changes as compared to radiographs.

Loading-Induced Reduction in Sclerostin as a Mechanism of Subchondral Bone PlateSclerosis in Mouse Knee Joints During Late-Stage Osteoarthritis.

To establish an unbiased, 3-dimensional (3-D) approach that quantifies subchondral bone plate (SBP) changes in mouse joints, and to investigate the mechanism that mediates SBP sclerosis at a late stage of osteoarthritis (OA). A new micro-computed tomography (micro-CT) protocol was developed to characterize the entire thickness of the SBP in the distal femur of a normal mouse knee. Four mouse models of severe joint OA were generated: cartilage-specific Egfr-knockout (Egfr-CKO) mice at 2 months after surgical destabilization of the medial meniscus (DMM), Egfr-CKO mice with aging-related spontaneous OA, wild-type (WT) mice at 10 months after DMM, and WT mice at 14 weeks after DMM plus hemisectomy of the meniscus (DMMH) surgery. As an additional model, mice with knockout of the sclerostin gene (Sost-KO) were subjected to DMMH surgery. Knee joints were examined by micro-CT, histology, and immunohistochemical analyses. Examination of the mouse distal femur by 3-D micro-CT revealed a positive correlation between SBP thickness and the loading status in normal knees. In all 4 mouse models of late-stage OA, SBP sclerosis was restricted to the areas under severely eroded articular cartilage. This was accompanied by elevated bone formation at the bone marrow side of the SBP and a drastic reduction in the levels of sclerostin in osteocytes within the SBP. Unlike in WT mice, no further increase in the thickness of the SBP was observed in response to DMMH in Sost-KO mice. Since focal stress on the SBP underlying sites of cartilage damage increases during late stages of OA, these findings establish mechanical loading-induced attenuation of sclerostin expression and elevation of bone formation along the SBP surface as the major mechanisms characterizing subchondral bone phenotypes associated with severe late-stage OA in mice.

In vivo biomechanical behavior of the trapeziometacarpal joint in healthy and osteoarthritic subjects

BackgroundThe contact biomechanics of the trapeziometacarpal joint have been investigated in several studies. However, these led to conflicting results and were mostly performed in vitro. The purpose of this study was to provide further insight on the contact biomechanics of the trapeziometacarpal joint by in vivo assessment of healthy and osteoarthritic subjects. MethodsThe hands of 16 healthy women and 6 women with trapeziometacarpal osteoarthritis were scanned in positions of maximal thumb extension, flexion, abduction and adduction during three isometric tasks (lateral key pinch, power grasp and jar twist) and in thumb rest posture (relaxed neutral). Three-dimensional surface models of the trapezium and first metacarpal were created for each thumb configuration. The articular surface of each bone was measured in the neutral posture. A computed tomography-based proximity mapping algorithm was developed to calculate the distance between opposing joint surfaces, which was used as a surrogate for intra-articular stress. FindingsDistinct proximity patterns were observed across tasks with a recurrent pattern reported on the volar aspect of the first metacarpal. The comparison between healthy and arthritic subjects showed a significantly larger articular area, in parallel with a significant joint space narrowing and an increase in proximity area in arthritic subjects. We also observed severe articular deformations in subjects with late stage osteoarthritis. InterpretationThis study has increased our insight in the contact biomechanics of the trapeziometacarpal joint during tasks and positions of daily life in healthy and arthritic subjects, which might contribute to a better understanding of the occurrence mechanisms of degenerative diseases such as osteoarthritis.

TOTAL KNEE ARTHROPLASTY;

Objectives: We aim to evaluate the level of satisfaction after total knee arthroplastyprocedure in the patient population at a tertiary care hospital in Karachi, Pakistan, and to assessthe relationship between patient satisfaction and the outcome based on traditional scores.Methods: Study Design: Case series for determination of patient satisfaction. Period: Oneyear duration from April 2015 to May 2016. Setting: Tertiary care centre in Karachi, Pakistan.The inclusion criteria was all the patients with late stage osteoarthritis of the knee joint andunderwent total knee arthroplasty at our institute. Data was analyzed using SPSS version 22.Results: A total of n= 102 patients were included in the study while n= 109 knee surgerieswere done in total (n= 95 patients had unilateral surgery, while n= 7 patients had bilateralsurgeries on both the knee joints) n= 58 patients were females while n= 44 patients weremales, the median age was 60 years, patients had a mean body mass index (BMI) of 27kg/m2. Of the total surgeries performed n= 100 were in the satisfaction group while n= 9 were inthe dissatisfaction group. The majority of the patients reported that they would recommend theprocedure. The co morbid conditions did not affect the patient’s level of satisfaction having ap value of 0.678. In the dissatisfied group, there was no significant difference when it comes togender, the mean age of patients in the dissatisfaction group was higher than the mean age ofpatients in the satisfaction. We found that WOMAC scores for functioning and the final WOMACscores were correlated with patient satisfaction and that was statistically significant, similarlySF-36 form patients were satisfied about the improvement in the physical health while they didnot improve the mental health aspect of their disease. Conclusion: According to our studytotal knee arthroplasty is an effective treatment for osteoarthritis of the knee, patient satisfactionis correlated with post-operative WOMAC function and overall scores, and SF-36 physicalcomponent. It is important to keep patients expectations in check through proper counseling.

English

Objectives: We aim to evaluate the level of satisfaction after total knee arthroplastyprocedure in the patient population at a tertiary care hospital in Karachi, Pakistan, and to assessthe relationship between patient satisfaction and the outcome based on traditional scores.Methods: Study Design: Case series for determination of patient satisfaction. Period: Oneyear duration from April 2015 to May 2016. Setting: Tertiary care centre in Karachi, Pakistan.The inclusion criteria was all the patients with late stage osteoarthritis of the knee joint andunderwent total knee arthroplasty at our institute. Data was analyzed using SPSS version 22.Results: A total of n= 102 patients were included in the study while n= 109 knee surgerieswere done in total (n= 95 patients had unilateral surgery, while n= 7 patients had bilateralsurgeries on both the knee joints) n= 58 patients were females while n= 44 patients weremales, the median age was 60 years, patients had a mean body mass index (BMI) of 27kg/m2. Of the total surgeries performed n= 100 were in the satisfaction group while n= 9 were inthe dissatisfaction group. The majority of the patients reported that they would recommend theprocedure. The co morbid conditions did not affect the patient’s level of satisfaction having ap value of 0.678. In the dissatisfied group, there was no significant difference when it comes togender, the mean age of patients in the dissatisfaction group was higher than the mean age ofpatients in the satisfaction. We found that WOMAC scores for functioning and the final WOMACscores were correlated with patient satisfaction and that was statistically significant, similarlySF-36 form patients were satisfied about the improvement in the physical health while they didnot improve the mental health aspect of their disease. Conclusion: According to our studytotal knee arthroplasty is an effective treatment for osteoarthritis of the knee, patient satisfactionis correlated with post-operative WOMAC function and overall scores, and SF-36 physicalcomponent. It is important to keep patients expectations in check through proper counseling.

Safety and Efficacy of Intra-articular Injection of Platelet-Rich Plasma in Patients With Ankle Osteoarthritis.

An intra-articular injection of platelet-rich plasma (PRP) may be an effective treatment for osteoarthritis (OA). However, its efficacy in ankle OA has not been investigated yet. The purpose of this study was to assess the safety and efficacy of an intra-articular injection of PRP in patients with ankle OA during a 24-week period. Twenty ankles of 20 patients with varus-type ankle OA who received intra-articular injections of PRP were evaluated. PRP was extracted from whole blood by using the double-spin technique. Three injections of 2-mL PRP were administered to the ankle at an interval of 2 weeks under ultrasonographic guidance. Adverse events and efficacy were assessed at 4, 12, and 24 weeks after the last injection. Clinical outcomes were assessed by using the visual analog scale (VAS) for pain, the Japanese Society for Surgery of the Foot (JSSF) ankle/hindfoot scale, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q). No serious adverse effects were observed during the follow-up period. The VAS and JSSF scale scores significantly decreased from baseline to 4, 12, and 24 weeks after treatment ( P < .001). The mean score in the pain-related subscale of the SAFE-Q significantly improved from baseline to 12 weeks after treatment ( P = .04). Overall, the amount of pain reduction was maximal at 12 weeks after the last injection, and the effect was reduced at 24 weeks. The patients with late-stage OA had worse scores in all outcomes than those with early-stage OA. Intra-articular injections of PRP resulted in no serious adverse effects and significantly reduced pain in the patients with ankle OA. PRP treatment can be safe and effective and may be an option in the treatment of ankle OA. Level IV, case series.

Local application of adipose-derived mesenchymal stromal cells in experimental inflammatory OA results in interleukin-1β-mediated attraction of PMNs and reduced S100A8/A9 release

Purpose: Recent studies have demonstrated that mild synovitis in early phases of osteoarthritis (OA) is conducive to development of joint damage. OA synovitis is characterized by elevated levels of pro-inflammatory factors like S100A8, S100A9, interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). S100A8/A9 was found to be crucial in mediating joint destruction in inflammatory experimental OA. Previously we found that adipose-derived mesenchymal stromal cells (ASCs) exhibit immunosuppressive characteristics and reduce joint pathology after local application into mouse knee joints with experimental inflammatory OA. This protective effect is only perceived after intra-articular injection in early but not late stage OA, suggesting that the effect may be mediated by an inflammatory environment. Our objective was to examine the working mechanism of ASCs after early injection in experimental OA. Methods: Experimental OA was induced by injection of collagenase into murine knee joints (CiOA). Total knee joints were stained with haematoxylin/eosin and the PMN-specific antibody NIMP-R14. ASCs were isolated from murine adipose tissue and stimulated for 24 hours with IL-1β or S100A8/A9. Gene expression in stimulated cells was analyzed using qPCR. Protein levels of chemokines and cytokines were measured in culture supernatant using Luminex. Migration of MACS isolated bone marrow (BM-) PMNs towards ASC-conditioned medium (CM) was examined using Transwell membranes. ASCs were co-cultured with BM-PMNs and analyzed using histology and Luminex. Results: Injection of ASCs into day 7 CiOA knee joints (when synovitis and IL-1β and S100A8/A9 levels are highest) caused a strong attraction of particularly PMN-like cells and their clustering around ASCs in the synovium shortly after injection (6 hours), which was confirmed by immunohistochemistry. IL-1β stimulation of ASCs in vitro strongly increased gene expression of PMN-attracting chemokines KC, CXCL5, and CXCL7 as well as protein levels of KC, whereas S100A8/A9 did not. The migration of BM-PMNs through Transwell membranes towards CM of IL-1β-stimulated ASCs was significantly increased (from 5% to 10%) when compared to CM of non-stimulated ASCs. Next, ASCs were co-cultured with BM-PMNs in the presence or absence of IL-1β. After 6 hours, a clear clustering of neutrophils around ASCs was observed, with a significant increase in the number of ASCs clustering with PMNs, as well as a significantly elevated number of clustering PMNs per ASC after IL-1β stimulation. Interestingly, association of PMNs with ASCs lead to a significantly diminished release of KC protein by ASCs (69% and 76% lower after 24 h and 48 h respectively), as well as a significantly reduced release of S100A8/A9 protein by the PMNs. This coincided with lowering of S100A8/A9 levels in washouts of inflamed synovium 6 h and 48 h after injection of ASCs in day 7 CiOA knee joints. Conclusions: Local application of ASCs in inflamed CiOA knee joints results in attraction and clustering of PMNs with ASCs in the synovium. This presumably runs via IL-1β-mediated up-regulation of chemokine release by ASCs, and ultimately results in significantly lowered levels of S100A8/A9. This research was supported by the Dutch Arthritis Association.

In vitro cell surface markers are insufficient to identify in vivo/in situ multipotent synovial mesenchymal stem cells isolated from normal or osteoarthritic knees

Purpose: Osteoarthritis (OA) is a chronic disease that results in the degeneration of the articular cartilage, but also effects all tissues present in the joint. Current treatments for OA patients focus on pain/symptom relief, however, the core persisting issue of cartilage degeneration remains unmodified. Synovial mesenchymal stem cells derived from the synovium (sMSCs), are an attractive source for articular cartilage regeneration since they demonstrate robust chondrogenic capacity. However, it is now becoming accepted that MSC populations can demonstrate significant phenotypically heterogeneity, which in turn, may affect their potential therapeutic efficacy. Furthermore, it remains unknown if this heterogeneity is natural (e.g. multiple MSC sub-populations present) or if MSCs are influenced by factors in vivo (such as the disease stage of the individual) and/or in vitro (such as culture microenvironment). Additionally, the methods used to define MSCs, such as marker profile could be influenced by varying laboratory/cell culture conditions suggesting that cell surface markers present on MSCs in vitro could be distinct from those that are present in vivo. Therefore, it may be possible that in vitro defined MSC markers may be unreliable to use as a standard to isolate MSCs directly from in vivo/in situ which would be necessary to understand and characterize MSC heterogeneity. A more complete understanding of MSC heterogeneity would allow us to identify and purify only sMSCs that have both self-renewal capacity as well as tri-lineage potential. To address this gap in knowledge we re-assessed the cell surface markers in vivo that are widely used to identify and purify MSCs in vitro. To accomplish this aim and also address questions on MSC heterogeneity, we examined the cell surface marker profiles (in vivo/in situ vs. in vitro) between clonal sMSCs isolated from OA and normal individuals. Additionally, we correlated the cell surface profile in situ with the tri-lineage potential to determine if the differentiation potential of sMSCs can be predicted based on their in situ cell surface expression profile. Methods: Synovium tissue was collected from knees of late stage OA patients (n = 15) and normal controls (n = 21). These biopsies were digested with collagenase type IV and the cell suspension was stained for: MSCs markers (CD90, CD44, CD73, CD271, CD105), a macrophage marker (CD68), and a viability marker (FVS510). An unbiased index sorted approach was utilized where 1 cell/well (per 96 well plate) was sorted based on the absence of CD68 and FVS510. Expanded clones were differentiated into adipocytes, chondrocytes and osteoblasts. Differentiation was analyzed via qPCR and histology. Each in vitro expanded clonal population was also re-examined for surface marker expression. Results: Figure 1 displays the differentiation capacity of 4 clones isolated from a single OA patient. Regardless of the in situ marker profiles expression, all sMSC clones, when cultured in vitro, converged to a unified marker profile of: CD90+, CD44+, CD73+ and CD105+. The in situ marker profile that was correlated with multipotent differentiation capacity of sMSCs was found to be similar between OA and normal clones (CD90+, CD44+, and CD73+). A second cohort of patients was recruited to validate the in situ MSC profile, however, it was found that isolation of CD90+, CD44+, and CD73+ triple positive cells didn't guarantee multipotent differentiation potential as tested by qPCR and histology analysis. Conclusions: This study has demonstrated that using in vitro defined MSC markers to select sMSCs populations directly from human synovial tissue is not specific and the markers currently used by the field are not capable of distinguishing MSCs with or without full differentiation capacity if employed in situ/in vivo. Furthermore, after reviewing in situ vs. in vitro surface marker expression data, it was found that all sMSC sub-populations present in situ (based on marker expression) converge to an indiscriminate profile after culturing. Overall, this suggests that at least some of the MSC markers employed are likely artifacts of the cell culturing process. Thus, the results of this project raise a potentially larger question regarding the identification of MSCs with these standard markers. Do these markers truly describe MSCs? This question should be thoroughly addressed before MSC therapies are continued to be delivered to patients suffering from OA.

Erratum to: Can We Identify Patients with High Risk of Osteoarthritis Progression Who Will Respond to Treatment? A Focus on Epidemiology and Phenotype of Osteoarthritis.

Osteoarthritis is a syndrome affecting a variety of patient profiles. A European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and the European Union Geriatric Medicine Society working meeting explored the possibility of identifying different patient profiles in osteoarthritis. The risk factors for the development of osteoarthritis include systemic factors (e.g., age, sex, obesity, genetics, race, and bone density) and local biomechanical factors (e.g., obesity, sport, joint injury, and muscle weakness); most also predict disease progression, particularly joint injury, malalignment, and synovitis/effusion. The characterization of patient profiles should help to better orientate research, facilitate trial design, and define which patients are the most likely to benefit from treatment. There are a number of profile candidates. Generalized, polyarticular osteoarthritis and local, monoarticular osteoarthritis appear to be two different profiles; the former is a feature of osteoarthritis co-morbid with inflammation or the metabolic syndrome, while the latter is more typical of post-trauma osteoarthritis, especially in cases with severe malalignment. Other biomechanical factors may also define profiles, such as joint malalignment, loss of meniscal function, and ligament injury. Early- and late-stage osteoarthritis appear as separate profiles, notably in terms of treatment response. Finally, there is evidence that there are two separate profiles related to lesions in the subchondral bone, which may determine benefit from bone-active treatments. Decisions on appropriate therapy should be made considering clinical presentation, underlying pathophysiology, and stage of disease. Identification of patient profiles may lead to more personalized healthcare, with more targeted treatment for osteoarthritis.

Dynamic cyclic compression modulates the chondrogenic phenotype in human chondrocytes from late stage osteoarthritis

Human osteoarthritic chondrocytes (hOACs) are characterized by their “dedifferentiated” and catabolic phenotype and lack the ability for restoring their inherent functions by themselves. Here we investigated whether extrinsically supplemented mechanical signal via compression loading would affect the phenotype of hOACs. Specifically, we applied cyclic compression loading on cultured hOACs-collagen constructs and measured the expression of the major chondrogenic factors, cell-matrix interaction molecules and matrix degradation enzymes. Dynamic compression loading stimulates the expression and nuclear localization of sox9 in hOACs and reduces the catabolic events via downregulated expression of collagenases. These results contribute to better understanding towards mechanoregulation of hOACs.

Platelet-Rich Plasma Injections for Advanced Knee Osteoarthritis: A Prospective, Randomized, Double-Blinded Clinical Trial.

Background:Intra-articular injections of platelet-rich plasma (PRP) to treat symptoms of knee osteoarthritis (OA) have been successfully used in young patients and in the early stages of disease. No previous studies have analyzed outcomes of PRP injections during the late stages.Hypothesis:PRP reduces pain and leads to a more effective and lasting functional recovery than corticosteroid with local anesthetic.Study Design:Randomized controlled trial; Level of evidence, 2.Methods:A total of 75 patients with symptomatic knee OA (Kellgren-Lawrence grade 3 to 4) were enrolled in this study between August 2013 and July 2014. Patients were randomized to treatment either with a single leukocyte-reduced PRP or corticosteroid intra-articular injection. The primary variable was visual analog scale assessment at 1 month. Secondary outcomes were the Knee injury and Osteoarthritis Outcome Score (KOOS) and Short Form–36 (SF-36) at 1, 3, and 6 months after treatment. Patient satisfaction at final follow-up was assessed. Both groups were homogeneous and comparable in baseline characteristics.Results:All variables improved in both groups. Statistical differences between groups were not found for the majority of the outcome variables, although the magnitude of improvements tended to be greater in the PRP group. Quality-of-life differences between values at 3 and 6 months versus baseline increased significantly more in the study group (P = .05 and .03, respectively), and so did general health perception differences at 6 months (P = .018).Conclusion:A single PRP intra-articular injection is effective for relieving pain and improving activities of daily living and quality of life in late-stage knee OA. For patients with late-stage knee OA who are 67 years or older, 1 intra-articular injection of PRP has similar results to 1 shot of corticosteroid.

Expression of IL-1β Receptor Antagonist in Patients with Severe Osteoarthritis of the Knee–The Mechanism Limiting the Inflammation in Osteoarthritis

Introduction: Expression of interleukin-1β (IL-1β) in the synovial fluid of patients with osteoarthritis has been confirmed. The overall effect of this cytokine can be described as a chondrocyte-dependent cartilage destructive potential. The interleukin-1β receptor antagonist (IL-1Ra) blocks the interaction between IL-1β and its receptor on the cell surface. Human chondrocytes and synoviocytes produce IL-1Ra in a response to stimulation by IL-1β and IL-6. The local production of IL-1Ra in the joint has a protective effect against the catabolic action of IL-1β. Material and Methods: Synovial fluid and blood serum were obtained from 31 patients undergoing knee replacement surgery because of osteoarthritis. For comparison, samples were obtained from another 30 patients during diagnostic or therapeutic arthroscopy performed because of knee injury. The samples were analyzed for IL-1β and IL-1Ra using enzyme-linked immunosorbent assay. The U Mann-Whitney test and Spearman's test, as well as receiver operating characteristic (ROC) were used for statistical analysis. Results: Statistical analysis showed that the concentration of IL-1Ra in serum was significantly higher in the osteoarthritis group compared to the injury group (p=0.0001), and there was a positive correlation of IL-1Ra concentration in the serum and in the synovial fluid (correlation coefficient R=0.41; significance p=0.02). In the osteoarthritis group there was a very high negative correlation between the intensity of pain and the concentration of IL-1Ra in the synovial fluid (correlation coefficient R=-0.75; significance p<0.000001). Furthermore very high negative correlation was observed between the intensity of pain and level of this cytokine in serum (R=0.86; p<0.000001). For the measurements of IL-1Ra in serum the sensitivity of this test was 71.0%, specificity 70.0%, positive prediction of a result was 71.0%, negative prediction 70.0%, and the area under the ROC curve was 0.792. Conclusion: Late stage osteoarthritis is characterized by a systemic inflammatory reaction with high concentration of IL-1Ra in serum, which is positively correlated with its concentration in the synovial fluid. Pain in patients with late stage osteoarthritis may be reduced due to the high concentration of anti-inflammatory IL-1Ra both in the synovial fluid and in blood serum. The measurement of IL-1Ra in serum is a reliable immunoassay test that determines the status of osteoarthritis.

Morphological and structural evaluation of trabecular bone in early and late stage of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease that occurs mostly in the knee and in the hip. It is expected that more than 20% of the population over the age of 60 in Europe and in the United States will show signs and symptoms associated with OA, and that one-third of OA patients will experience disability and immobilization, hence the motivation for this research aimed at achieving new insights into the bone structure alterations induced by this disease. In an original approach, the 3D reconstructions obtained by high-resolution X-ray micro-CT were the starting point for: i) a morphological examination and 2) structural 3D analyses by numerical simulation of the bone architectures behavior, thus providing an extended description of the changes in osteoarthritic bone as disease progress. This paper presents the first results obtained by the combination of morphological and structural 3D analyses from on high-resolution micro-CT reconstructions of trabecular bone in early and late stage hip OA.