End-stage Osteoarthritis Patients Research Articles

Metabolomic Profiles and Pathways in Osteoarthritic Human Cartilage: A Comparative Analysis with Healthy Cartilage.

Osteoarthritis (OA) is a chronic joint disease with heterogenous metabolic pathology. To gain insight into OA-related metabolism, metabolite extracts from healthy (n = 11) and end-stage osteoarthritic cartilage (n = 35) were analyzed using liquid chromatography-mass spectrometry metabolomic profiling. Specific metabolites and metabolic pathways, including lipid and amino acid pathways, were differentially regulated in osteoarthritis-derived and healthy cartilage. The detected alterations in amino acids and lipids highlighted key differences in bioenergetic resources, matrix homeostasis, and mitochondrial alterations in OA-derived cartilage compared to healthy cartilage. Moreover, the metabolomic profiles of osteoarthritic cartilage separated into four distinct endotypes, highlighting the heterogenous nature of OA metabolism and the diverse landscape within the joint in patients. The results of this study demonstrate that human cartilage has distinct metabolomic profiles in healthy and end-stage OA patients. By taking a comprehensive approach to assess metabolic differences between healthy and osteoarthritic cartilage and within osteoarthritic cartilage alone, several metabolic pathways with distinct regulation patterns were detected. Additional investigation may lead to the identification of metabolites that may serve as valuable indicators of disease status or potential therapeutic targets.

Can Patients Who Have Low-Grade Hip Osteoarthritis Expect the Same Outcome After Total Hip Arthroplasty Compared to Those Who Have End-Stage Osteoarthritis? – A Matched Case-Control Study

BackgroundTotal hip arthroplasty (THA) is an effective procedure for patients with end-stage hip osteoarthritis (OA). In addition, when hip preservation surgery is no longer indicated due to the presence of early or mild arthritic changes, THA can also be considered. Whether these patients can expect the same outcome after THA as patients who have end-stage OA remains unclear. The goal of this study was to compare the clinical outcomes after THA of patients who have low-grade OA versus a matched cohort with end-stage OA. MethodsThis is a retrospective, single-center, multisurgeon case-control study in a high-volume referral center. Based on a cohort of 2,189 primary anterior approach THAs (1,815 patients), 50 low-grade OA cases were matched 1:1 by age, sex, and body mass index to 50 controls who have end-stage OA. Patient-reported outcome measures (PROMs) were Hip Disability and Osteoarthritis Outcome Scores and Short Form-36. ResultsNo significant differences in preoperative PROMs between low-grade and end-stage OA patients were found, except for 36-item Short Form Survey pain (33.0 versus 41.0; P = .045). In both groups a significant improvement of all PROMs was found postoperatively. However, all Hip Disability and Osteoarthritis Outcome Scores were significantly lower in the low-grade OA group compared to the end-stage OA group. In the group with low-grade OA, a significantly lower percentage of patients achieved the minimal clinically important difference and substantial clinical benefit after THA compared to the group with end-stage OA. ConclusionsPatients who have low-grade OA can expect substantial clinical improvement after THA. However, the improvement is lower compared to patients who have end-stage OA. A thorough understanding of the factors that may lead to inferior clinical outcomes is imperative to improving the indications for THA in individuals who have low-grade OA.

Genomic heterozygosity is associated with a lower risk of osteoarthritis

BackgroundGenomic heterozygosity has been shown to confer a health advantage in humans and play a protective role in complex diseases. Given osteoarthritis (OA) is a highly polygenic disease, we set out to determine if an association exists between OA and genomic heterozygosity.ResultsEnd-stage knee and hip OA patients and healthy controls were recruited from the Newfoundland and Labrador (NL) population. The Arthritis Research UK Osteoarthritis Genetics (arcOGEN) consortium database was utilized as a replication cohort. DNA was extracted from blood samples and genotyped. Individual rates of observed heterozygosity (HetRate) and heterozygosity excess (HetExcess) relative to the expected were mathematically derived, and standardized to a z-score. Logistic regression modeling was used to examine the association between OA and HetRate or HetExcess. A total of 559 knee and hip OA patients (mean age 66.5 years, body mass index (BMI) 33.7 kg/m2, and 55% females) and 118 healthy controls (mean age 56.4 years, BMI 29.5 kg/m2, and 59% female) were included in the NL cohort analysis. We found that OA had an inverse relationship with HetRate and HetExcess with odds ratios of 0.64 (95% CI: 0.45–0.91) and 0.65 (95% CI: 0.45–0.93) per standard deviation (SD), respectively. The arcOGEN data included 2,019 end-stage knee and hip OA patients and 2,029 healthy controls, validating our findings with HetRate and HetExcess odds ratios of 0.60 (95% CI: 0.56–0.64) and 0.44 (95% CI: 0.40–0.47) per SD, respectively.ConclusionsOur results are the first to clearly show evidence, from two separate cohorts, that reduced genomic heterozygosity confers a risk for the future development of OA.

Identification of CD64 as a marker for the destructive potential of synovitis in osteoarthritis.

OA is characterized by cartilage degeneration and persistent pain. The majority of OA patients present with synovitis, which is associated with increased cartilage damage. Activated synovial macrophages are key contributors to joint destruction. Therefore, a marker that reflects the activation of these cells could be a valuable tool to characterize the destructive potential of synovitis and benefit monitoring of OA. Here, we aimed to investigate the use of CD64 (FcγRI) as a marker to characterize the damaging potential of synovitis in OA. Synovial biopsies were obtained from end-stage OA patients that underwent joint replacement surgery. CD64 protein expression and localization was evaluated using immunohistochemistry and immunofluorescence and quantified using flow cytometry. qPCR was performed to measure the expression of FCGR1 and OA-related genes in synovial biopsies, and in primary chondrocytes and primary fibroblasts stimulated with OA conditioned medium (OAS-CM). Our data exposed a wide range of CD64 expression in OA synovium and showed positive correlations between FCGR1 and S100A8, S100A9, IL1B, IL6 and MMP1/2/3/9/13 expression. CD64 protein correlated with MMP1, MMP3, MMP9, MMP13 and S100A9. Furthermore, we observed that synovial CD64 protein levels in source tissue for OAS-CM significantly associated with the OAS-CM-induced expression of MMP1, MMP3 and especially ADAMTS4 in cultured fibroblasts, but not chondrocytes. Together, these results indicate that synovial CD64 expression is associated with the expression of proteolytic enzymes and inflammatory markers related to structural damage in OA. CD64 therefore holds promise as marker to characterize the damaging potential of synovitis.

Surgery avoidance rates among total knee replacement candidates following a non-invasive biomechanical intervention: A retrospective cohort study

Background Nearly twenty million people are affected by osteoarthritis (OA) across the UK. For end-stage knee OA, total knee replacement (TKR) is considered as the standard of care, but this major surgery carries high costs, long waiting lists, and risk for further revision surgeries. Health systems are therefore looking for effective alternatives to treat these cohorts, significantly delaying, and potentially avoiding joint replacement surgery altogether. The purpose of this study was to examine the 2-year surgery avoidance rate amongst TKR candidates that received a non-invasive biomechanical intervention. Methods A retrospective clinical audit was conducted on 365 NHS patients with end-stage knee OA patients eligible for TKR. Each patient was individually fitted with a non-invasive, shoe-like, biomechanical device, that alters the foot center of pressure, minimizes reported symptoms, and promotes neuromuscular control training using convex pods under the sole. Patients used the device for short periods during activities of daily living and were followed for two years. The primary outcome was surgery status after 2 years. Secondary outcomes were evaluated using the generalized linear mixed-models procedure and included changes in pain, function (WOMAC and Oxford Knee Score (OKS), and spatiotemporal gait measured at 3, 6, 12, and 24 months from baseline. Results Of the 365 candidates for TKR, 305 (84%) avoided surgery at 2 years. Patients displayed significant clinical improvements over time. Six months after starting treatment, average pain decreased by 42%, average function improved by 39%, and average OKS increased by 7.6 points. These continued to improve over the 2 years. All spatial-temporal gait measures improved over time (p<0.001). Conclusions The current results suggest that a non-invasive biomechanical treatment may help end-stage knee OA patients delay knee replacement surgery for at least 2 years or avoid it altogether. This treatment may provide an effective non-surgical alternative for managing these patients in the community, alleviating pain, and improving gait and function.

Typical response of CD14++CD16– monocyte to knee synovial derived mediators as a key target to overcome the onset and progression of osteoarthritis

ObjectiveSynovitis with increased infiltration of immune cells is observed in osteoarthritis (OA). Given the inflammatory condition of synovitis, we explored the protein profile of OA synovium (OAS) and its effect on circulating monocytes activation, migration, and functional commitments.MethodsKnee-synovium was acquired from end-stage OA (N = 8) and trauma patients (Trauma baseline control: TBC; N = 8) for characterization using H&E histology, IHC (iNOS), LCMS-QTOF, and MALDI-imaging. Response of peripheral blood monocytes to OAS conditioned-media (OACM) was observed using transwell (n = 6). The migrated cells were captured in SEM, quantified using phase-contrast microphotographs, and their activation receptors (CCR2, CXCR2, CX3CR1, and CD11b), pro-inflammatory genes, and phagocytic potential were studied using flow cytometry, gene expression array/qPCR, and latex beads (LB) phagocytosis assay, respectively.ResultsThe Venn diagram displayed 119 typical proteins in OAS, while 55 proteins in TBCS. The STRING protein network analysis indicated distinctive links between proteins and gene ontology (GO) and revealed proteins associated with leukocyte-mediated immunity in OAS as compared to TBC. The MALDI-imaging showed typical localized proteins at 2234.97, 2522.61, 2627.21, 3329.50, and 3539.69 m/z and IHC confirmed pro-inflammatory iNOS expression in OA synovium. CD14++CD16– classical monocytes significantly migrated in OACM and expressed CCR2, CXCR2, and CD11b receptors, TNFRSF11A, MAPK1, S100A8, HSPB1, ITGAL, NFATC1, IL13RA1, CD93, IL-1β, TNF-α, and MYD88 genes and increased LB uptake as compared to SFM.ConclusionOur findings suggest that the differential protein profile of OA synovium and the classical monocytes migrated, activated, and functionally committed in response to these mediators could be of therapeutic advantage.

The application of Caprini Risk Assessment Model in evaluation of deep vein thrombosis for patients with end-stage osteoarthritis before arthroplasty

BackgroundDeep vein thrombosis (DVT) was a fatal complication of knee arthroplasty. We had neglected the risk factors of preoperative DVT although patients undergoing knee arthroplasty were at high risk for VTE. This study was to determine the risk factors for preoperative DVT and application of Caprini Risk Assessment Model (RAM) in patients with end-stage knee osteoarthritis (OA).MethodsWe retrospectively analyzed 1808 cases with end-stage knee OA undergoing primary knee arthroplasty from May 2015 to December 2020. Based on the results of ultrasonography in lower extremities, all patients were divided into non-DVT group and DVT group. Distribution of risk factors and risk levels were compared using χ2 test between two groups. Binary logistic regression analysis was used to determine the risk factors and relationship of risk levels and preoperative DVT.ResultsThe incidence of preoperative DVT was 5.53% (n = 100). Distribution of the study population by risk level was low, 4.09%; moderate, 23.95%; high, 66.98%; and highest 4.98%. Female (P = 0.002), age (P = 0.012), swollen legs (P = 0.035) and history of blood clots (P < 0.001) was correlated with preoperative DVT. Difference among four risk levels was significant (P = 0.007). Patients with highest risk level had statistically significant association with preoperative DVT (P = 0.005, OR = 2.93, 95%CI [1.375–6.246]).ConclusionThe incidence of preoperative DVT was 5.53% in end-stage knee OA patients. The gender (female) and age were independent risk factors for preoperative DVT. The risk group classification by Caprini RAM was significantly associated with preoperative DVT. The usage of Caprini RAM before knee arthroplasty may be beneficial for prophylaxis of DVT.

CD8+ T Cells in OA Knee Joints Are Differentiated into Subsets Depending on OA Stage and Compartment

Osteoarthritis (OA) is no longer considered a purely degenerative disease. OA is defined as a disease of the entire joint, in which inflammation occurs in various joint tissues. The overall aim of this study was to analyze the presence and polarization of CD8+ T cell subsets in OA knee joints, in relation to the OA stage and compartment (synovial fluid (SF), synovial membrane (SM,) peripheral blood (PB)). A quantitative flow analysis of CD8+ T cell subsets to compare the SF, SM, PB, was performed in patients with different stages of OA (early, unicondylar and bicondylar OA). Samples of the SF, SM and PB were harvested from a total of 55 patients at the time of surgery. Early OA was confirmed by independent surgeons intraoperatively. Uni- and bicondylar OA was confirmed and graded by two plane radiographs. Samples were analyzed by flow cytometry for surface markers, and cytokines by intracellular staining (ICS). CD8+ T cells were shown to be differentiated into pro-inflammatory IFN-γ producing Tc1 and IL-17A producing Tc17, as well as anti-inflammatory IL-4 producing Tc2. All CD8+ T cell subsets (Tc1, Tc17, and Tc2) were detected in both the SM and SF. The percentage of CD8+ T cell subsets of the total CD8+ T cell population was dependent on the OA stage and compartment. Compared with the peripheral blood (PB), the proportion of CD8+IFN-γ+ Tc1 and CD8+IL-17A+ Tc17 was significantly increased in OA SF. This was confirmed in our data for both early OA and end-stage OA. In the SM samples of end-stage OA patients, the proportion of CD8+IL-17A+ Tc17 was significantly increased compared to the PB. Comparing SF and SM samples of end-stage OA patients, the proportion of CD8+IFN-γ+ Tc1 was significantly increased in SF, whereas there were no differences concerning CD8+IL-4+ Tc2 and CD8+IL-17A+ Tc17. End-stage OA samples showed a significant increase of CD8+IL-4+ Tc2 in the SM for both unicondylar and bicondylar OA compared to early OA. CD8+ T cells infiltrating the SM and SF in OA knees are differentiated into IFN-γ-, IL-17A-, and IL-4-producing CD8+ T cell subsets (Tc1, Tc17, Tc2). This differentiation depends on the OA stage and OA compartment. Further investigation of CD8+ T cell subsets and their interaction with other inflammatory cells such as CD4+ T cells and macrophages may help to identify novel therapeutic anti-inflammatory strategies for containing OA progression.

Synovial fluid from end-stage osteoarthritis induces proliferation and fibrosis of articular chondrocytes via MAPK and RhoGTPase signaling

Alterations in the composition of synovial fluid have been associated with adverse effects on cartilage integrity and function. Here, we examined the phenotypic and proliferative behavior of human articular chondrocytes when cultured in vitro for 13 days with synovial fluid derived from end-stage osteoarthritis patients. Chondrocyte proliferation and phenotypical changes induced by osteoarthritic synovial fluid were analyzed using DNA staining, RT-qPCR, immunostainings, and immunoblotting. The molecular mechanisms by which osteoarthritic synovial fluid induced fibrosis and proliferation were studied using a phospho-protein antibody array and luciferase-based transcription factor activity assays. Specific pathway inhibitors were used to probe the involvement of pathways in fibrosis and proliferation. Prolonged stimulation with osteoarthritic synovial fluid sustained chondrocyte proliferation and induced profound phenotypic changes, favoring a fibrotic over a chondrogenic or hypertrophic phenotype. A clear loss of chondrogenic markers at both the transcriptional and protein level was observed, while expression of several fibrosis-associated markers were upregulated over time. Phospho-kinase analysis revealed activation of MAPK and RhoGTPase signaling pathways by osteoarthritic synovial fluid, which was confirmed by elevated transcriptional activity of Elk-1 and SRF. Inhibitor studies revealed that ERK played a central role in the loss of chondrocyte phenotype, while EGFR and downstream mediators p38, JNK and Rac/Cdc42 were essential for fibrosis-associated collagen expression. Finally, we identified EGF signaling as a key activator of chondrocyte proliferation. Osteoarthritic synovial fluid promoted chondrocyte fibrosis and proliferation through EGF receptor activation and downstream MAPK and RhoGTPase signaling.

Duloxetine in OsteoArthritis (DOA) study: effects of duloxetine on pain and function in end-stage hip and knee OA \u2013 a pragmatic enriched randomized controlled trial

BackgroundSome osteoarthritis (OA) patients experience inadequate pain relief from analgesics like acetaminophen and nonsteroidal anti-inflammatory drugs. This could be the result of experienced non-nociceptive centralized pain. Placebo-controlled randomized trials (RCT) have proven the effectiveness of duloxetine for OA and several chronic pain conditions where central sensitization (CS) is one of the key underlying pain mechanisms.ObjectivesAssess the efficacy of an 8-week duloxetine treatment compared to usual care in end-stage knee and hip OA patients with a level of centralized pain.DesignPragmatic, enriched, open-label RCT.MethodsPatients were randomized to duloxetine or to care-as-usual. Primary outcome was pain in the index joint, measured with the pain domain of the Knee injury and Osteoarthritis Outcome Score (KOOS) or the Hip disability and Osteoarthritis Outcome Score (HOOS). The intention-to-treat principle was used, with mixed-model repeated measures to analyze the effect.ResultsOne hundred eleven patients were randomized. Nearly 44% felt much to very much better after duloxetine usage compared to 0% in the care-as-usual group (p < 0.001). The duloxetine group scored 11.3 points (95%CI: 5.8, 16.8) better on the pain domain of the KOOS/HOOS (p < 0.001). Knee patients improved significantly more than hip patients (18.7 [95%CI: 11.3, 26.1] versus 6.0 [95%CI: − 2.6, 14.5] points better).ConclusionsAdding duloxetine treatment seems to be beneficial for end-stage knee OA patients with neuropathic-like symptoms (at risk of CS). End stage Hip OA patients seem to be nonresponsive to duloxetine.Trial registrationDutch Trial Registry with number NTR 4744 (15/08/2014) and in the EudraCT database with number 2013–004313-41.

Toward Preventing Arthritis: A Comparison of Synovial RNA in Osteoarthritic Ankles and Knees

Category:Ankle; Ankle Arthritis; Basic Sciences/Biologics; TraumaIntroduction/Purpose:Osteoarthritis (OA) of the lower limb is a debilitating, incurable, expensive and prevalent condition in people over 45. Although ankle posttraumatic OA (PTOA) has the highest incidence, primary OA is increasingly recognized. The difference in OA incidence between lower limb joints is partly driven by differences in cartilage architecture and chondrocyte function at each site, with ankle chondrocytes showing reduced responsiveness to inflammatory mediators and more metabolic activity than those in the knee. Synovium also contributes to the pathogenesis of OA, however its potentially differential role in knee versus ankle OA remains an unanswered question. We aim to understand the molecular contribution of synovial dysregulation in the progression of ankle and knee OA to uncover candidate pathways for the development of targeted therapeutic paradigms.Methods:After obtaining informed consent from patients undergoing total knee or ankle replacement, basic surgical, past medical history, and imaging data was collected. Synovium samples were harvested during surgery and processed for RNA. Bulk 150 bp, paired-end RNA seq was conducted using standard protocols using the Illumina NovaSeq6000 platform. After quality control trimming, reads were aligned to human reference genome (GRCh38) using STAR (v 2.5) using the Maximum Mappable Prefix method and HTSeq (V0.6.1) was used to index mappable reads per gene. Counts were corrected for gene length using the FPKM method. Differential expression was determined using the edgeR (v 3.16.5) package for R, after adjustment using a scaling normalization factor and P-values were corrected using the Benjamini and Hochberg method. Similarities between samples were determined using Spearman Correlation and degree of similarity was visualized considering the first three Principal Components (PC).Results:RNA was obtained from 6 end-stage ankle OA, 1 end-stage knee OA patients. Of the ankle samples, two were PTOA and the remaining four were primary OA. The PTOA and the primary OA samples showed high sample correlation regardless of class (correlation coefficients ranged from 0.844 to 0.941). In contrast, the total knee sample was less correlated with the ankle samples (correlation coefficients ranged from 0.719 to 0.878). By using the first three PC, we observed that there was no obvious differentiation among the ankle OA samples, but there was clear separation between ankle and total knee samples. We observed an enrichment of genes annotated to the Gene Ontology clusters 'Extracellular Structure Organization' and 'Inflammatory Response' when comparing the two types of OA.Conclusion:These initial pilot results of an ongoing study support our hypothesis that synovial transcriptome differs between the knee and ankle in end-stage osteoarthritis and that anatomic site is a larger driver of synovial expression differences than OA type. This is supported by previous differences reported between ankle and knee chondrocytes in end-stage OA. These findings emphasize the importance of investigating synovial tissue to better understand the microenvironment of the ankle joint and pathogenesis of all etiologies of OA. The ultimate goal is the development of clinical tests and therapeutics aimed at slowing or discontinuing the degenerative process in ankle arthritis.

Increased Ratio of CD14++CD80+ Cells/CD14++CD163+ Cells in the Infrapatellar Fat Pad of End-Stage Arthropathy Patients.

ObjectivesThis study sought to identify the ratio of M1/M2 cells in the infrapatellar fat pads (IFP) and subcutaneous fat tissues (SC) of osteoarthritis (OA) and rheumatoid arthritis (RA) patients. The clinical features of OA and RA patients treated with or without biological disease-modifying anti-rheumatic drugs (bDMARDs) were also assessed.MethodsIFP and SC were collected from patients with OA and RA who are undergoing total knee arthroplasty (TKA). CD14-positive cells were then isolated from these samples. Flow cytometry was used to determine the number of CD14++CD80+ cells and CD14++CD163+ cells. The expression levels of lipid transcription factors, such as sterol regulatory element-binding protein 1 (SREBP1) and liver X receptor alpha (LXRA), and inflammatory cytokines were also evaluated.ResultsTwenty OA patients and 22 RA patients were enrolled in this study. Ten of the RA patients (45.4%) received bDAMRDs before TKA. On average, a fivefold increase in the number of CD14-positive cells and lower expression levels of SREBP1C and LXRA were observed in OA IFP relative to OA SC; however, these results were not obtained from the RA samples. The median ratio of CD14++CD80+ cells/CD14++CD163+ cells of OA IFP was 0.87 (0.76–1.09, interquartile range), which is higher to that of OA SC with a lower ratio (p = 0.05835).ConclusionsThe quantity and quality of CD14-positive cells differed between IFP and SC in arthropathy patients. To our knowledge, this is the first study to characterize the ratio of M1/M2 cells in the IFP and SC of end-stage OA and RA patients. The increased ratio of CD14++CD80+ cells/CD14++CD163+ cells in the IFP from patients with OA and RA treated with bDMARDs indicated that inflammation was localized in the IFP. As adipose tissue-derived innate immune cells were revealed as one of the targets for regulating inflammation, further analysis of these cells in the IFP may reveal new therapeutic strategies for inflammatory joint diseases.

Effect of preoperative duloxetine treatment on postoperative chronic residual pain after total hip or knee arthroplasty: a randomised controlled trial

ObjectivesA key predictor for developing chronic residual pain after total knee or hip arthroplasty (TKA/THA) is sensitisation. Sensitisation can be defined as an ‘increased responsiveness of nociceptive neurons in the...

Patellar retraction versus eversion on functional outcomes in total knee replacement: a randomized controlled study protocol

BackgroundPatellar mobilization technique during total knee replacement (TKR) has been debated, with some suggesting that lateral retraction, rather than eversion, of the patella may be beneficial. This randomized controlled trial was to investigate the effects of patellar eversion on functional outcomes in TKR.Methods and analysisThis single-center, prospective, randomized controlled test will be conducted in Jingjiang People's Hospital. Primary end-stage osteoarthritis patients that prepared for unilateral TKR were randomized to one of two patellar exposure techniques during the primary total knee arthroplasty: lateral retraction or eversion. The informed consent will be acquired in each patient. The primary outcome was operation time, length of hospital stay, and straight leg raising time. Second outcomes including Insall-Salvati ratio; range of motion at 1 month, 3 months, and 1 year following TKR; visual analog scale (VAS) at 1 month, 3 months; and Knee Society Score (KSS) score at 1 year following TKR. The significance level was defaulted as P < .05.ResultsResults will be published in relevant peer-reviewed journals.ConclusionOur study aims to systematically assess the functional outcomes of patellar eversion for TKR patients, which will provide clinical guidance for TKR patients.

Interleukin-17A Causes Osteoarthritis-Like Transcriptional Changes in Human Osteoarthritis-Derived Chondrocytes and Synovial Fibroblasts In Vitro.

Increased interleukin (IL)-17A has been identified in joints affected by osteoarthritis (OA), but it is unclear how IL-17A, and its family members IL-17AF and IL-17F, can contribute to human OA pathophysiology. Therefore, we aimed to evaluate the gene expression and signalling pathway activation effects of the different IL-17 family members in chondrocytes and synovial fibroblasts derived from cartilage and synovium of patients with end-stage knee OA. Immunohistochemistry staining confirmed that IL-17 receptor A (IL-17RA) and IL-17RC are expressed in end-stage OA-derived cartilage and synovium. Chondrocytes and synovial fibroblasts derived from end-stage OA patients were treated with IL-17A, IL-17AF, or IL-17F, and gene expression was assessed with bulk RNA-Seq. Hallmark pathway analysis showed that IL-17 cytokines regulated several OA pathophysiology-related pathways including immune-, angiogenesis-, and complement-pathways in both chondrocytes and synovial fibroblasts derived from end-stage OA patients. While overall IL-17A induced the strongest transcriptional response, followed by IL-17AF and IL-17F, not all genes followed this pattern. Disease-Gene Network analysis revealed that IL-17A-related changes in gene expression in these cells are associated with experimental arthritis, knee arthritis, and musculoskeletal disease gene-sets. Western blot analysis confirmed that IL-17A significantly activates p38 and p65 NF-κB. Incubation of chondrocytes and synovial fibroblasts with anti-IL-17A monoclonal antibody secukinumab significantly inhibited IL-17A-induced gene expression. In conclusion, the association of IL-17-induced transcriptional changes with arthritic gene-sets supports a role for IL-17A in OA pathophysiology. Future studies should further investigate the role of IL-17A in the OA joint to establish whether anti-IL-17 treatment could be a potential therapeutic option in OA patients with an inflammatory phenotype.

A promoter-based bioassay that predicts the effect of the osteoarthritic microenvironment on cartilage formation

Purpose: Recent developments have demonstrated that intrinsic cartilage repair is possible in certain osteoarthritis (OA) patients. A growing body of literature suggests an influence of joint microenvironment on intrinsic cartilage repair via affecting chondrogenic capacity of stem cells; i.e. this environment can be permissive or non-permissive for repair. A method able to discriminate between patients with permissive or non-permissive articular joint microenvironments would be of great use to predict the outcome of cartilage repair therapies. We postulate this can be best done with a bioassay, as in a bioassay different cellular signals are integrated and multiple reporters can be measured simultaneously. Therefore, our goal is to develop a rapid bioassay that will be able to discriminate between permissive and non-permissive joint conditions. Methods: To construct our bioassay, promoter sequences of four different genes were isolated from human gDNA using PCR; i.e. IL6 (-600 till +78), IL8 (-572 till +100 bp), ADAMTS5 (-1432 till +37) and WISP1 (-833 till +50) and cloned in the pNL1.2 vector (Promega) which expressed the unstable Nano luciferase. Promoter reporter constructs were efficiently introduced by transient transfection with lipofectamine in H11 chondrocytes. Transfected cells were stimulated for 24 hours with OA-synovium conditioned medium (OAs-cm), as a substitute for OA synovial fluid, from sixteen individual patients and luciferase activity was measured on a luminometer. OAs-cm was obtained by culturing synovium from end-stage OA patients for 24 hours. Fold change was calculated relative to control stimulation. These results hereof were correlated (Pearson) with the ability of these OAs-cm to inhibit sGAG formation during chondrogenesis. This was tested by chondrogenic differentiation of human fetal bone-marrow derived MSCs in an established three-dimensional pellet culture model. Pellets were cultured for 14 days in serum-free chondrogenic medium (without dexamethasone). After 10 days of differentiation, MSCs were exposed to the OAs-cm from the same sixteen individual donors. Cartilage formation was determined at day 14 by measuring sulfated glycosaminoglycan (sGAG) content. Results: Stimulation of the hIL6, hIL8 and hADAMTS5 promoter reporters with OAs-cm form sixteen different patients resulted in an up-regulation of promoter activity compared to control stimulation, whereas stimulation of the hWISP1 promoter reporter resulted in a down-regulation of the promoter activity compared to control. Interestingly, large heterogeneity was observed in the response of the promoter reporters between the OAs-cm from distinct patients with hIL6 (FC 33.9 ± 32.3), hIL8 (FC 32.2 ± 27.7), hADAMTS5 (FC 3.7 ± 2.4) and hWISP1 (FC 0.4 ± 0.24). Furthermore, individual OAs-cm reduced sGAG content of differentiating MSCs by a range between 3% and 65%. Significant correlations were found between the fold change of the promoter activity and the percentage of inhibition on chondrogenesis. We observed a positive correlation with hIL6 (p=0.01 and r=0.67), hIL8 (p=0.01 and r=0.66) and with hADAMTS5 (p=0.01 and r=0.72), whereas a negative correlation was seen with hWISP1 (p=0.002 and r=-0.78). To validate if this correlation will predict the effect of other OAs-cm, sixteen newly collected OAs-cm were tested and eleven out of sixteen OAs-cm were within the 95% prediction interval. Conclusions: The current study demonstrates that our reporter assays are able to predict the effect of the joint microenvironment (OAs-cm) on cartilage formation as measured by sGAG production. Significant correlations were observed between the fold change of these promoter reporters and the inhibition of chondrogenic capacity of hMSCs, with positive correlations for hIL6, hIL8 and hADAMTS5 and a negative correlation with hWISP1. Our promoter constructs appear to be able to predict repair capacity of stem cells and could be of use for a personalized treatment strategy.

Discrepant histological diagnoses: A cause of early low FJS-12 score and if untreated, unhappy Total Knee Arthroplasty patient

PurposeTotal Knee Arthroplasty (TKA) is one of the most successful operations in orthopedics. Still, a sizable percentage of patients (20%) remain dissatisfied after a well-executed TKA. The study aims to examine the excised synovium from the suprapatellar region in osteoarthritic knees during TKA and evaluate the histopathology (HP) report to know whether discrepant diagnoses affect the Forgotten Joint Score-12 at various time intervals. MethodsThis is a prospective cohort study. Two hundred (160 female; 40 male) end-stage osteoarthritis patients who underwent primary TKA were studied. An inclusion criterion was patient with end-stage osteoarthritis. Clinically and serologically proven rheumatoid arthritis patients were excluded from the study. The synovium excised during the TKA procedure was sent for the HP examination. The statistical significance was measured with the Chi-square test and two-sample t-test. ResultsA total of 184 out of the 200 patients (92%) knee synovium showed HP features of osteoarthritis. The discordant diagnoses and discrepant diagnosis rate was 8% and 7%, respectively, which is statistically significant by Chi-square test (p value < 0.0001 and p value = 0.0001). 14 of the patients (12 F:2 M) showed histological features of inflammatory/rheumatoid arthritis who were treated, two patients (all female) showed HP features of villonodular synovitis. The mean (SD) improvement in FJS-12 at six weeks in the concordant group (25.3 [17.6]) is significantly more than the discrepant group (15.3 [12.5]), p-value 0.0385. Conclusion8% of our patients exhibited unexpected results. The study showed a 7% rate of discrepant diagnosis. This discrepant diagnosis if missed and untreated, would have affected the function and long-term survival of the implanted TKA.

Quantitative three-dimensional collagen orientation analysis of human meniscus posterior horn in health and osteoarthritis using micro-computed tomography

Knee osteoarthritis (OA) is associated with meniscal degeneration that may involve disorganization of the meniscal collagen fiber network. Our aims were to quantitatively analyze the microstructural organization of human meniscus samples in 3D using micro-computed tomography (μCT), and to compare the local microstructural organization between OA and donor samples. We collected posterior horns of both medial and lateral human menisci from 10 end-stage medial compartment knee OA patients undergoing total knee replacement (medial & lateral OA) and 10 deceased donors without knee OA (medial & lateral donor). Posterior horns were dissected and fixed in formalin, dehydrated in ascending ethanol concentrations, treated with hexamethyldisilazane (HMDS), and imaged with μCT. We performed local orientation analysis of collagenous microstructure in 3D by calculating structure tensors from greyscale gradients within selected integration window to determine the polar angle for each voxel. In donor samples, meniscus bundles were aligned circumferentially around the inner border of meniscus. In medial OA menisci, the organized structure of collagen network was lost, and main orientation was shifted away from the circumferential alignment. Quantitatively, medial OA menisci had the lowest mean orientation angle compared to all groups,-24° (95%CI -31 to-18) vs medial donor and-25° (95%CI -34 to-15) vs lateral OA. HMDS-based μCT imaging enabled quantitative analysis of meniscal collagen fiber bundles and their orientations in 3D. In human medial OA menisci, the collagen disorganization was profound with overall lower orientation angles, suggesting collagenous microstructure disorganization as an important part of meniscus degradation.

Bone mineral density assessment by DXA in rheumatic patients with end-stage osteoarthritis undergoing total joint arthroplasty

BackgroundPatients with rheumatic diseases have a high risk for joint destruction and secondary osteoarthritis (OA) as well as low bone mineral density (BMD, i.e., osteoporosis). While several factors may lead to low BMD in these patients, the value of BMD measurements in rheumatic patients with end-stage OA scheduled for total joint arthroplasty is unknown.MethodsIn this retrospective cross-sectional study of 50 adults with secondary OA due to rheumatic diseases, we evaluated dual energy X-ray absorptiometry (DXA) measurements of both hips and the spine performed within 3 months prior to arthroplasty (n = 25 total hip arthroplasty, THA; n = 25 total knee arthroplasty, TKA). We analyzed various demographic and disease-specific characteristics and their effect on DXA results by using group comparisons and multivariate linear regression models.ResultsAlthough patients undergoing TKA were younger (63.2 ± 14.2 vs. 71.0 ± 10.8 yr., p = 0.035), osteoporosis was observed more frequently in patients scheduled for TKA than THA (32% vs. 12%). Osteopenia was detected in 13/25 patients (52%) in both the THA and TKA cohort. In the THA cohort, female sex, lower BMI and prednisolone use were associated with lower T-score in the hip. In TKA patients, higher OA grade determined by Kellgren-Lawrence score was associated with lower T-score in the hip of the affected side.ConclusionsOsteoporosis is present in a considerable frequency of rheumatic patients with end-stage OA, and THA and TKA patients show distinct frequencies and risk factors of low BMD. Our findings point to a potential value of DXA regarding preoperative evaluation of bone status.

Association between knee alignment, osteoarthritis disease severity, and subchondral trabecular bone microarchitecture in patients with knee osteoarthritis: a cross-sectional study

BackgroundKnee osteoarthritis (OA) is a common disabling disease involving the entire joint tissue, and its onset and progression are affected by many factors. However, the current number of studies investigating the relationship between subchondral trabecular bone (STB), knee alignment, and OA severity is limited. We aimed to investigate the variation in tibial plateau STB microarchitecture in end-stage knee OA patients and their association with knee alignment (hip-knee-ankle, HKA, angle) and OA severity.MethodsSeventy-one knee OA patients scheduled for total knee arthroplasty (TKA) underwent preoperative radiography to measure the HKA angle and Kellgren-Lawrence grade. Tibial plateaus collected from TKA were scanned using micro-computed tomography to analyze the STB microarchitecture. Histological sections were used to assess cartilage degeneration (OARSI score). Correlations between the HKA angle, OA severity (OARSI score, Kellgren-Lawrence grade), and STB microarchitecture were evaluated. Differences in STB microstructural parameters between varus and valgus alignment groups based on the HKA angle were examined.ResultsThe HKA angle was significantly correlated with all STB microarchitecture parameters (p < 0.01). The HKA angle was more correlated with the medial-to-lateral ratios of the microarchitecture parameters than with the medial or lateral tibia plateaus. The HKA angle and all STB microarchitecture parameters are significantly correlated with both the OARSI score and Kellgren-Lawrence grade (p < 0.01).ConclusionsThe STB microarchitecture is associated with the HKA angle and OA severity. With the increase of the knee alignment deviation and OA severity, the STB of the affected side tibial plateau increased in bone volume, trabecular number, and trabecular thickness and decreased in trabecular separation.