Optical imaging (HandScan) can identify ultrasound remission in rheumatoid arthritis.

BACKGROUND: Identifying remission is of high importance in rheumatoid arthritis (RA) because remission is associated with less structural progression. We investigated the efficacy of a new optical imaging device, HandScan, to identify RA remission, as defined by ultrasound (US). METHODS: 61 RA patients were included. Disease activity was evaluated by clinical assessment and US, using gray-scale (GS) and Power Doppler (PD). HandScan determined unitary optical spectral transmission (OST) values for wrists, metacarpophalangeal and proximal interphalangeal joints. At the patient level, three composite HandScan (HS) scores were calculated: total HS score; disease activity score OST (DAS-OST) and DAS-OST without patient global assessment (PtGA). Using ROC curves, we determined HS cut-offs to identify US-defined remission. RESULTS: At the joint level, unitary OST values significantly correlated with GS synovitis [odds ratio (OR) 2.43, p < 0.0001] and PD positivity (OR 3.72, p = 0.0002 ). At the patient level, total HS score and DAS-OST were significantly associated with all gray-scale US (GSUS) and power doppler US (PDUS) parameters evaluated (synovitis number and grade, synovial thickness, PD grade) (p < 0.05). The cut-off to identify US-defined remission at the joint level was of 0.92, giving an 81% sensitivity and a 96% positive predictive value (PPV). At the patient level, ROC-curves failed to identify a robust cut-off for the total HS score, but did identify a cut-off (3.68) for DAS-OST to identify US-defined remission, but with lower sensitivity (75%), specificity (56%) and PPV (67%). CONCLUSIONS: HandScan is a non-invasive optical imaging technique providing OST values that correlate with GSUS and PDUS parameters. In addition, HandScan is able to reliably identify US-defined remission in RA at the joint level, with a good sensitivity and high PPV. At the patient level, HandScan DAS-OST can also determine US remission (while total HS score failed to do so), but with lower performance.

Hypophosphatasia Presenting as a Chronic Diffuse Pain Syndrome with Extra-Articular Calcifications.

Hypophosphatasia is a rare genetic disease characterized by abnormal alkaline phosphatase activity and deficiency of bone and teeth mineralization. Hypophosphatasia is well known in pediatrics with typical presentations in children, but mild forms can also be present in adults and are difficult to detect. We present the case of a 50-year-old woman referred for pain management, with a previous diagnosis of fibromyalgia. The association of clinical features (diffuse pain syndrome, early dental loosening, personal history of two fractures with osteoporosis, and family history of osteoporosis) with radiographic (heterotopic calcifications of the yellow and interspinous lumbar ligaments) and biological (low levels of total alkaline phosphatase) indices was suggestive of hypophosphatasia, which was confirmed by genetic analysis. We review and discuss the association between hypophosphatasia, musculoskeletal pain, and calcium pyrophosphate deposition and the importance of raising the diagnosis of adult-onset hypophosphatasia when facing these two rheumatologic entities.

[The management of gout]. / Vignette thérapeutique de l'étudiant. Prise en charge de la goutte.

We describe the case of a patient with a history of gout, who presents with a new episode of acute gout. Based on this clinical case, we will discuss the management of acute gout. We will then address the management of chronic gout, i.e., the indications for a hypouricemic treatment and the caution required when starting this treatment. Finally, we will address the need for a holistic care, discussing the change of certain co-medications, screening for cardiovascular comorbidities and providing diet and life-style recommendations.

Nous décrivons le cas d'un patient, goutteux connu, qui présente un nouvel accès aigu. Nous discutons tout d'abord, à partir de ce cas clinique, la prise en charge aiguë de la crise de goutte. Nous abordons ensuite les indications de mise en place d'un traitement de fond hypo-uricémiant et les précautions à prendre lors de cette introduction. Enfin, nous détaillons la prise en charge holistique, en évoquant les modifications de certaines thérapeutiques, le dépistage des comorbidités cardiovasculaires et les conseils hygiéno-diététiques.

[Lung disease associated with rheumatoid arthritis]. / La pathologie pulmonaire associée à la polyarthrite rhumatoïde.

Rheumatoid arthritis is a chronic inflammatory systemic disease. Pulmonary manifestations are the most common extra-articular involvements and can impact all components of the respiratory system: parenchyma, pleura, vessels and airways, all complications that are briefly described in this article. Interstitial lung disease is the most common of these and is associated with significant morbidity and mortality. Its detection and monitoring are based on spirometry and thoracic imaging. Specific treatments are initiated in order to reduce the risk of disease flare up but may themselves in case of toxicity be associated with respiratory manifestations, either directly or by promoting infectious complications.

La polyarthrite rhumatoïde est une pathologie systémique inflammatoire chronique. Les manifestations pulmonaires représentent l'atteinte extra-articulaire la plus fréquente et peuvent affecter tous les composants du système respiratoire : le parenchyme, la plèvre, les vaisseaux et les voies aériennes, complications décrites brièvement dans cet article. La pneumopathie interstitielle diffuse en est la plus commune et associée à une morbi-mortalité importante. Son dépistage et son suivi reposent sur les épreuves fonctionnelles et l'imagerie thoracique. Des traitements spécifiques sont initiés afin de limiter au mieux l'évolution pulmonaire, mais peuvent eux-mêmes être associés à des manifestations respiratoires, soit directement, soit en favorisant des complications infectieuses.

[Diagnosis of osteoporosis]. / Vignette diagnostique de l'étudiant. Prise en charge diagnostique de l'ostéoporose.

We here describe the case of a post-menopausal woman presenting with a recent vertebral fracture and cortical osteopenia on bone dual energy X-ray absorptiometry. Based on this case, we will discuss the definition and diagnosis of osteoporosis as well as the indications to treat, which go beyond the densitometric-based definition of osteoporosis. We will also address the osteoporosis screening recommendations, and the blood workup required before treatment initiation. The choice of the treatment, its duration and the non-pharmacological measures will be discussed in another article.

Nous décrivons le cas d'une patiente ménopausée présentant un tassement vertébral récent et une ostéopénie corticale sur la densitométrie osseuse. Nous discutons, à partir de ce cas clinique, la définition et le diagnostic de l'ostéoporose, ainsi que les indications thérapeutiques, qui dépassent le cadre de la simple définition densitométrique. Nous abordons ensuite les indications de dépistage de l'ostéoporose, ainsi que le bilan biologique et étiologique à réaliser avant l'instauration du traitement. Le choix du traitement reminéralisateur, la durée du traitement et la prise en charge non médicamenteuse de l'ostéoporose seront discutés dans une autre vignette.

Senescence-Driven Inflammatory and Trophic Microenvironment Imprints Mesenchymal Stromal/Stem Cells in Osteoarthritic Patients.

Senescent cells promote progressive tissue degeneration through the establishment of a combined inflammatory and trophic microenvironment. The cellular senescence state has therefore emerged as a central driving mechanism of numerous age-related diseases, including osteoarthritis (OA), the most common rheumatic disease. Senescence hallmarks are detectable in chondrocytes, synoviocytes and sub-chondral bone cells. This study investigates how the senescence-driven microenvironment could impact the cell fate of resident osteoarticular mesenchymal stromal/stem cells (MSCs) that are hence contributing to OA disease progression. For that purpose, we performed a comparative gene expression analysis of MSCs isolated from healthy donors that were in vitro chronically exposed either to interferon-gamma (IFN-γ) or Transforming Growth Factor beta 1 (TGFß1), two archetypical factors produced by senescent cells. Both treatments reduced MSC self-renewal capacities by upregulating different senescence-driven cycle-dependent kinase inhibitors. Furthermore, a common set of differentially expressed genes was identified in both treated MSCs that was also found enriched in MSCs isolated from OA patients. These findings highlight an imprinting of OA MSCs by the senescent joint microenvironment that changes their matrisome gene expression. Altogether, this research gives new insights into OA etiology and points to new innovative therapeutic opportunities to treat OA patients.

[A breakthrough in the management of postmenopausal osteoporosis with very high fracture risk : romosozumab (Evenity®), a humanized monoclonal anti-sclerostin antibody]. / Une nouveauté dans la prise en charge de l'ostéoporose post-ménopausique à très haut risque fracturaire : le romosozumab (Evenity®), un anticorps monoclonal anti-sclérostine.

Romosozumab (Evenity®) is a humanized monoclonal anti-sclerostin antibody. It represents a major breakthrough in the treatment of osteoporosis: while most treatments inhibit bone resorption, romosozumab has a dual effect, by increasing bone formation and reducing bone resorption. It is reimbursed in postmenopausal osteoporosis in patients with very high fracture risk (i.e. after a recent major fracture, occurring within two years). Its ideal use, in the therapeutic sequence for post-menopausal women, is as first line treatment in case of a recent major fracture. It is contraindicated in case of hypocalcemia and personal history of stroke or myocardial infarction.

Le romosozumab (Evenity®) est un anticorps monoclonal humanisé anti-sclérostine. Il représente une avancée majeure dans le traitement de l'ostéoporose : alors que la majorité des traitements remboursés inhibent la résorption osseuse, le romosozumab présente un effet «mixte¼, en augmentant la formation osseuse et en réduisant la résorption. Il est remboursé dans l'ostéoporose post-ménopausique chez les patientes à très haut risque fracturaire (c'est-à-dire après une fracture majeure récente, survenue dans les deux ans). Son utilisation idéale, dans la séquence thérapeutique chez la femme ménopausée, le positionne en première ligne en cas de fracture majeure récente. Il est contre-indiqué en cas d'hypocalcémie et d'antécédent personnel d'accident vasculaire cérébral ou d'infarctus du myocarde.

Airflow obstruction as a marker of adverse prognosis in rheumatoid arthritis.

Objectives: In our study, we explored the specific subgroup of patients with rheumatoid arthritis (RA) suffering from obstructive lung disease (OLD) and its impact on morbi-mortality. Methods: Our retrospective study included 309 patients suffering from RA with either obstructive (O-RA) or non-obstructive patterns (non-O-RA). OLD was defined based on the Tiffeneau index at the first available pulmonary functional test (PFT). Survival was then calculated and represented by a Kaplan-Meier curve. The comparison between the populations considered was performed by the Log-Rank test. Results: Out of the 309 RA patients, 102 (33%) had airway obstruction. The overall survival time was significantly lower in the O-RA group than in the non-O-RA group (n = 207) (p < 0.001). The median survival time was 11.75 years in the O-RA group and higher than 16 years in the non-O-RA group. Multivariate analysis identified OLD as an independent risk factor for mortality (HR 2.20; 95% CI 1.21-4.00, p < 0.01). Conclusion: Airway obstruction can be an independent risk factor of mortality in RA and should be considered as an early marker of poor prognosis. Further prospective longitudinal studies are required in order to determine the best clinical management for O-RA patients.

Lung Function Impairment, Associating Hyperinflation with Impaired Diffusion Capacity and Transfer Coefficient, Is a Risk Factor for Hip Osteoporosis in Patients with Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a risk factor for osteoporosis. Our objective is to determine if functional indices associated with emphysema on pulmonary function tests (DLCO-diffusion capacity of the lung for CO-; DLCO/AV-DLCO corrected for alveolar volume- and TLC-total lung capacity), considered alone or together, can identify COPD patients with osteoporosis. METHODS: 90 COPD patients underwent dual-energy X-ray absorptiometry (DEXA) and pulmonary function tests. RESULTS: 26% of the COPD patients were osteoporotic. In univariate analysis, each functional parameter associated with emphysema, analyzed separately, was not associated with osteoporosis. In contrast, patients with hyperinflation associated with impaired diffusion capacity and transfer coefficient, defined by the association of the three functional indices (DLCO < 70%, DLCO/AV < 80% and CPT > 115%), had significantly more osteoporosis at the total hip (OR: 5.9, CI: 1.5-23.8, p = 0.013). In multivariate analysis, this phenotype was confirmed as an independent factor associated with hip osteoporosis. In contrast, COPD airway obstruction severity, based on FEV1 (%), was not associated with osteoporosis. A lower BMI, female gender and age were also identified as osteoporosis risk factors. CONCLUSIONS: COPD patients with hyperinflation associated with impaired diffusion capacity and transfer coefficient are at higher risk for osteoporosis. Pulmonary function tests associated with emphysema detection can help to identify COPD patients with osteoporosis, in addition to the classical risk factors.

The Role of MCM9 in the Etiology of Sertoli Cell-Only Syndrome and Premature Ovarian Insufficiency.

Infertility in couples is a common problem, with both female and male factors contributing to similar extents. Severe, congenital disorders affecting fertility are, however, rare. While folliculogenesis and spermatogenesis are generally orchestrated via different mechanisms, some genetic anomalies can impair both female and male gametogenesis. Minichromosome maintenance complex component 9 (MCM9) is involved in DNA repair and mutations of the MCM9 gene have been previously reported in females with premature ovarian insufficiency (POI). MCM9 is also an emerging cancer risk gene. We performed next-generation and Sanger sequencing of fertility and related genes and hormonal and imaging studies in a kindred whose members had POI and disordered spermatogenesis. We identified a homozygous pathogenic MCM9 variant, c.394C>T (p.Arg132*) in three sisters affected by POI due to ovarian dysgenesis and their brother who had normal pubertal development but suffered from non-obstructive azoospermia. Testicular biopsy revealed Sertoli cell-only testicular histopathology. No evidence of early onset cancer was found in the homozygotic family members, but they were all young (<30 years) at the time of the study. In the male patient the homozygous MCM9 variant led to normal pubertal development and hormonal levels but caused a Sertoli-cell-only syndrome with non-obstructive azoospermia. In the homozygous females studied, the clinical, hormonal, and gonadal phenotypes revealed ovarian dysgenesis consistent with previous reports. Active screening for potential colorectal and other cancer risks in the homozygotic MCM9 subjects has been instigated.

Progressive fibrosing interstitial lung disease in rheumatoid arthritis: A retrospective study.

Background and objective: Rheumatoid arthritis associated-interstitial lung disease (RA-ILD) is the most common pulmonary manifestation of rheumatoid arthritis (RA) and an important cause of mortality. In patients suffering from interstitial lung diseases (ILD) from different etiologies (including RA-ILD), a significant proportion is exhibiting a fibrotic progression despite immunosuppressive therapies, defined as progressive fibrosing interstitial lung disease (PF-ILD). Here, we report the frequency of RA-ILD and PF-ILD in all RA patients' cohort at University Hospital of Liège and compare their characteristics and outcomes. Methods: Patients were retrospectively recruited from 2010 to 2020. PF-ILD was defined based on functional, clinical and/or iconographic progression criteria within 24 months despite specific anti-RA treatment. Results: Out of 1,500 RA patients, about one third had high-resolution computed tomography (HRCT) performed, 89 showed RA-ILD and 48 PF-ILD. RA-ILD patients were significantly older than other RA patients (71 old of median age vs. 65, p < 0.0001), with a greater proportion of men (46.1 vs. 27.7%, p < 0.0001) and of smoking history. Non-specific interstitial pneumonia pattern was more frequent than usual interstitial pneumonia among RA-ILD (60.7 vs. 27.0%) and PF-ILD groups (60.4 vs. 31.2%). The risk of death was 2 times higher in RA-ILD patients [hazard ratio 2.03 (95% confidence interval 1.15-3.57), p < 0.01] compared to RA. Conclusion: We identified a prevalence of PF-ILD of 3% in a general RA population. The PF-ILD cohort did not seem to be different in terms of demographic characteristics and mortality compared to RA-ILD patients who did not exhibit the progressive phenotype yet.

CEMIP (KIAA1199) regulates inflammation, hyperplasia and fibrosis in osteoarthritis synovial membrane.

Osteoarthritis (OA) synovial membrane is mainly characterized by low-grade inflammation, hyperplasia with increased cell proliferation and fibrosis. We previously underscored a critical role for CEMIP in fibrosis of OA cartilage. However, its role in OA synovial membrane remains unknown. An in vitro model with fibroblast-like synoviocytes from OA patients and an in vivo model with collagenase-induced OA mice were used to evaluate CEMIP-silencing effects on inflammation, hyperplasia and fibrosis. Our results showed that i. CEMIP expression was increased in human and mouse inflamed synovial membrane; ii. CEMIP regulated the inflammatory response pathway and inflammatory cytokines production in vitro and in vivo; iii. CEMIP induced epithelial to mesenchymal transition pathway and fibrotic markers in vitro and in vivo; iv. CEMIP increased cell proliferation and synovial hyperplasia; v. CEMIP expression was increased by inflammatory cytokines and by TGF-ß signaling; vi. anti-fibrotic drugs decreased CEMIP expression. All these findings highlighted the central role of CEMIP in OA synovial membrane development and underscored that targeting CEMIP could be a new therapeutic approach.

Influence of Glucocorticoids on Cellular Senescence Hallmarks in Osteoarthritic Fibroblast-like Synoviocytes.

Osteoarthritis (OA) is recognized as being a cellular senescence-linked disease. Intra-articular injections of glucocorticoids (GC) are frequently used in knee OA to treat synovial effusion but face controversies about toxicity. We investigated the influence of GC on cellular senescence hallmarks and senescence induction in fibroblast-like synoviocytes (FLS) from OA patients and mesenchymal stem cells (MSC). METHODS: Cellular senescence was assessed via the proliferation rate, ß-galactosidase staining, DNA damage and CKI expression (p21, p16INK4A). Experimental senescence was induced by irradiation. RESULTS: The GC prednisolone did not induce an apparent senescence phenotype in FLS, with even higher proliferation, no accumulation of ß-galactosidase-positive cells nor DNA damage and reduction in p21mRNA, only showing the enhancement of p16INK4A. Prednisolone did not modify experimental senescence induction in FLS, with no modulation of any senescence parameters. Moreover, prednisolone did not induce a senescence phenotype in MSC: despite high ß-galactosidase-positive cells, no reduction in proliferation, no DNA damage and no CKI enhancement was observed. CONCLUSIONS: We provide reassuring in vitro data about the use of GC regarding cellular senescence involvement in OA: the GC prednisolone did not induce a senescent phenotype in OA FLS (the proliferation ratio was even higher) and in MSC and did not worsen cellular senescence establishment.

Dissociation between 2-[18F]fluoro-2-deoxy-D-glucose positron emission computed tomography, ultrasound and clinical assessments in patients with non-severe rheumatoid arthritis, including remission.

BACKGROUND: Inflammation of patients joints with severe disease activity of rheumatoid arthritis (RA) has already been visualized and quantified by 2-[18F]fluoro-2-deoxy-D-glucose positron emission computed tomography ([18F] FDG PET/CT), but little is known about the metabolic status and its relationship with clinical and ultrasonography (US) metrology in patients with low/moderate activity or in remission. METHODS: Clinical assessments [based on 28-joint disease activity score (DAS28-CRP) and Clinical Disease Activity Index (CDAI)], [18F] FDG PET/CT, US and X-ray were performed on 63 RA patients classified into remission or low/moderate or severe disease activity groups. PET/CT was visually and then semi-quantitatively analysed by determining the standardized uptake value (SUV) of positive joints. RESULTS: Of the 1764 joints, 21.1% were tender only, 13.7% swollen only, 27.6% tender or swollen, 7.3% tender and swollen, 20.5% PET/CT-positive and 8.6% US-positive. PET and US measurements were correlated, albeit with poor concordance. The positive predictive value of PET/CT for clinical evaluation (tender and/or swollen) was low, whereas its negative predictive value was high. Highly significant differences were found with the number of PET/CT-positive joints and with cumulative SUV between "severe" and "non-severe" patients (including those in remission and those with low/moderate activity) and not between those classified as "remission" and "non-remission" or "remission" and "low/moderate activity". Moreover, the correlation between PET/CT measurements and clinical activity was positive only in the CDAI severe disease group. In patients in remission or with low/moderate activity, only 20-30% of joints were PET/CT-negative. In remission, PET/CT and US were positive in different joints, and PET/CT-positive but US-negative joints mainly exhibited RA (38.1%) or normal (49.2%) and not osteoarthritic (12.7%) X-ray patterns. CONCLUSIONS: [18F] FDG PET/CT was effective at distinguishing patients with severely active disease from other patients. In non-severe RA patients, including those in remission, PET/CT results are discordant from US and clinical observations. A longitudinal analysis is needed to explore the clinical relevance of such infra-clinical disease.

TFEB phosphorylation on Serine 211 is induced by autophagy in human synovial fibroblasts and by p62/SQSTM1 overexpression in HEK293 cells.

Autophagy receptor p62/SQSTM1 signals a complex network that links autophagy-lysosomal system to proteasome. Phosphorylation of p62 on Serine 349 (P-Ser349 p62) is involved in a cell protective, antioxidant pathway. We have shown previously that P-Ser349 p62 occurs and is rapidly degraded during human synovial fibroblasts autophagy. In this work we observed that fingolimod (FTY720), used as a medication for multiple sclerosis, induced coordinated expression of p62, P-Ser349 p62 and inhibitory TFEB form, phosphorylated on Serine 211 (P-Ser211 TFEB), in human synovial fibroblasts. These effects were mimicked and potentiated by proteasome inhibitor MG132. In addition, FTY720 induced autophagic flux, LC3B-II up-regulation, Akt phosphorylation inhibition on Serine 473 but down-regulated TFEB, suggesting stalled autophagy. FTY720 decreased cytoplasmic fraction contained TFEB but induced TFEB in nuclear fraction. FTY720-induced P-Ser211 TFEB was mainly found in membrane fraction. Autophagy and VPS34 kinase inhibitor, autophinib, further increased FTY720-induced P-Ser349 p62 but inhibited concomitant expression of P-Ser211 TFEB. These results suggested that P-Ser211 TFEB expression depends on autophagy. Overexpression of GFP tagged TFEB in HEK293 cells showed concomitant expression of its phosphorylated form on Serine 211, that was down-regulated by autophinib. These results suggested that autophagy might be autoregulated through P-Ser211 TFEB as a negative feedback loop. Of interest, overexpression of p62, p62 phosphorylation mimetic (S349E) mutant and phosphorylation deficient mutant (S349A) in HEK293 cells markedly induced P-Ser211 TFEB. These results showed that p62 is involved in regulation of TFEB phosphorylation on Serine 211 but that this involvement does not depend on p62 phosphorylation on Serine 349.

Topography of Bone Erosions at the Metatarsophalangeal Joints in Rheumatoid Arthritis: Bilateral Mapping by Computed Tomography.

OBJECTIVES: To describe the bilateral anatomical location of bone erosions (BE) at the metatarsophalangeal joints in patients with rheumatoid arthritis using computed tomography. MATERIALS AND METHODS: Eighteen consecutive patients with established rheumatoid arthritis prospectively underwent computed tomography of both forefeet. Each joint surface of the metatarsal heads (MTH) and the proximal phalangeal bases were divided into four quadrants: superior, plantar, tibial, and fibular. The number of BE was cumulatively counted per patient, side, joint, per joint surface, and quadrant. Descriptive statistics, paired and unpaired samples t-tests, Pearson's correlation coefficients, ANOVA 2, and variance component analysis were performed. RESULTS: There were 288 BE at the MTH and 66 at the proximal phalanges. The number of BE in one forefoot was a poor predictor of the absolute number of BE on the contralateral foot "r=0.54" and was unrelated to symptoms. The superior quadrants were less frequently affected than other quadrants for both the MTH "p<0.0001" and proximal phalanges "p<0.001." The tibial quadrant showed a higher number of BE compared to all other quadrants for MTH "p<0.03," proximal phalanges "p<0.01, and for the metatarsophalangeal joint as a whole "p<0.0001." Plantar and fibular quadrants were equally affected "p<0.05." CONCLUSION: BE were found more frequently on the tibial side of the MTH in patients with rheumatoid arthritis.

Modulation of αVß6 integrin in osteoarthritis-related synovitis and the interaction with VTN(381-397 a.a.) competing for TGF-ß1 activation.

Osteoarthritis is characterized by structural alteration of joints. Fibrosis of the synovial tissue is often detected and considered one of the main causes of joint stiffness and pain. In our earlier proteomic study, increased levels of vitronectin (VTN) fragment (amino acids 381-397) were observed in the serum of osteoarthritis patients. In this work, the affinity of this fragment for integrins and its putative role in TGF-ß1 activation were investigated. A competition study determined the interaction of VTN(381-397 a.a.) with αVß6 integrin. Subsequently, the presence of αVß6 integrin was substantiated on primary human fibroblast-like synoviocytes (FLSs) by western blot and flow cytometry. By immunohistochemistry, ß6 was detected in synovial membranes, and its expression showed a correlation with tissue fibrosis. Moreover, ß6 expression was increased under TGF-ß1 stimulation; hence, a TGF-ß bioassay was applied. We observed that αVß6 could mediate TGF-ß1 bioavailability and that VTN(381-397 a.a.) could prevent TGF-ß1 activation by interacting with αVß6 in human FLSs and increased α-SMA. Finally, we analyzed serum samples from healthy controls and patients with osteoarthritis and other rheumatic diseases by nano-LC/Chip MS-MS, confirming the increased expression of VTN(381-397 a.a.) in osteoarthritis as well as in lupus erythematosus and systemic sclerosis. These findings corroborate our previous observations concerning the overexpression of VTN(381-397 a.a.) in osteoarthritis but also in other rheumatic diseases. This fragment interacts with αVß6 integrin, a receptor whose expression is increased in FLSs from the osteoarthritic synovial membrane and that can mediate the activation of the TGF-ß1 precursor in human FLSs.

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.

Toward diagnostic relevance of the αVß5, αVß3, and αVß6 integrins in OA: expression within human cartilage and spinal osteophytes.

We previously reported 18FPRGD2 uptake by the coxofemoral lining, intervertebral discs and facet joint osteophytes in OA using PET/SCAN imaging. However, the molecular mechanism by which the PRGD2 tracer interacts with joint tissues and osteophytes in OA remains unclear. As PRGD2 ligands are expected to belong to the RGD-specific integrin family, the purpose of this study was (i) to determine which integrin complexes display the highest affinity for PRGD2-based ligands, (ii) to analyze integrin expression in relevant tissues, and (iii) to test integrin regulation in chondrocytes using OA-related stimuli to increase the levels of fibrosis and ossification markers. To this end, the affinity of PRGD2-based ligands for five heterodimeric integrins was measured by competition with 125I-echistatin. In situ analyses were performed in human normal vs. OA cartilage and spinal osteophytes. Osteophytes were characterized by (immuno-)histological staining. Integrin subunit expression was tested in chondrocytes undergoing dedifferentiation, osteogenic differentiation, and inflammatory stimulation. The integrins αVß5, αVß3, and αVß6 presented the highest affinity for PRGD2-based ligands. In situ, the expression of these integrins was significantly increased in OA compared to normal cartilage. Within osteophytes, the mean integrin expression score was significantly higher in blood vessels, fibrous areas, and cells from the bone lining than in osteocytes and cartilaginous zones. In vitro, the levels of integrin subunits were significantly increased during chondrocyte dedifferentiation (except for ß6), fibrosis, and osteogenic differentiation as well as under inflammatory stimuli. In conclusion, anatomical zones (such as OA cartilage, intervertebral discs, and facet joint osteophytes) previously reported to show PRGD2 ligand uptake in vivo expressed increased levels of αVß5, αVß3, and ß6 integrins, whose subunits are modulated in vitro by OA-associated conditions that increase fibrosis, inflammation, and osteogenic differentiation. These results suggest that the increased levels of integrins in OA compared to normal tissues favor PRGD2 uptake and might explain the molecular mechanism of OA imaging using the PRGD2-based ligand PET/CT.