http://arthritis-research.com/ The latest research articles published by Arthritis Research & Therapy 2010-02-09T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ IntroductionThis study aimed to investigate whether hydroxynonenal (HNE) depletion is responsible for the switch from cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1) to 5-lipoxygenase-activating protein (FLAP) and 5-lipoxygenase (5-LOX). Methods: For COX-2 and mPGES-1 studies, human osteoarthritic (OA) chondrocytes were stimulated at different incubation times (up to 24 hours) with a single or repetitive addition of 10 microM HNE to the cultures at 2 hour intervals, up to 14 hours. For 5-LOX and FLAP studies, cells were treated with a single addition of 10 microM HNE for 24 hours, 48 hours, and 72 hours in the presence or absence of naproxen (a nonspecific COX-2 inhibitor) or antibody anti-transforming growth factor-beta 1 (TGF-beta1. The protein levels of COX-2, mPGES-1 and early growth response factor-1 (Egr-1) transcription factor were evaluated by Western blot and that of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and TGF-beta1were determined with commercial kits. The levels of mPGES-1, FLAP and 5-LOX mRNA were measured by real-time RT-PCR. Transient transfection was performed to determine promoter activities of mPGES-1 and 5-LOX. Results: Single addition of 10 microM HNE to cultured chondrocytes induced PGE2 release as well as COX-2 and mPGES-1 expression at the protein and mRNA levels, with a plateau reached respectively at 8 and 16 hours of incubation, followed by a subsequent decline. However, repeated treatments with HNE prevented the decline of COX-2 and mPGES-1 expression that occurred with a single aldehyde addition. HNE induced mPGES-1 promoter activity, possibly through transcription factor Egr-1 activation. After 48 hours, when COX-2 expression decreased, LTB4 level rose through 5-LOX and FLAP up-regulation. The addition of naproxen to cultured chondrocytes revealed that FLAP and 5-LOX regulation by HNE required PGE2 production. Furthermore, our data showed that HNE significantly induced TGF-beta1 production. The addition of anti-TGF-beta1 antibody reduced HNE-induced 5-LOX and FLAP expression by 40%, indicating the partial involvement of a TGF-beta1-dependent mechanism. Conclusions: Our data demonstrate that the shunt to the FLAP and 5-LOX pathway in HNE-induced human OA chondrocytes is attributed to COX-2 and mPGES-1 inhibition, probably due to HNE depletion. PGE2 and TGF-beta1 are suggested to be involved in this regulation. http://arthritis-research.com/content/12/1/R21 Shu-Huang Chen Hassan Fahmi Qin Shi Mohamed Benderdour Arthritis Research & Therapy 2010, 12:R21 2010-02-09T00:00:00Z doi:10.1186/ar2926 Arthritis Research & Therapy 1478-6354 12 R21 2010-02-09T00:00:00Z PDF IntroductionLeptin is a peptide hormone with a role in bone metabolism and rheumatic diseases. The subchondral bone tissue plays a prominent role in the pathophysiology of osteoarthritis (OA), related to abnormal osteoblast (Ob) differentiation. Although leptin promotes the differentiation of Ob under normal condition, a role for leptin in OA Ob has not been demonstrated. Here we determined if endogenous leptin produced by OA Ob could be responsible for the expression of the abnormal phenotypic biomarkers observed in OA Ob. Methods: We prepared primary normal and OA Ob from subchondral bone of tibial plateaus removed for knee surgery of OA patients or at autopsy. We determined the production of leptin and of the long, biologically active, leptin receptors (OB-Rb) using RT-PCR, ELISA and Western blot analysis. We determined the effect of leptin on cell proliferation by BrdU incorporation and MTT assays, and we determined by Western blot analysis phospho 42/44 MAPK (p42/44 Erk1/2) and phospho p38 levels. We then determined the effect of the addition of exogenous leptin, leptin receptor antagonists, inhibitors of leptin signaling or siRNA techniques on the phenotypic features of OA Ob. Phenotypic features of Ob were determined by measuring alkaline phosphatase activity (ALP), osteocalcin release (OC), collagen type 1 production (CICP) and of Transforming growth factor-beta1 (TGF-beta1). Results: Leptin expression was increased ~5-fold and protein levels ~2-fold in OA Ob compared to normal. Leptin stimulated its own expression and the expression of OB-Rb in OA Ob. Leptin dose-dependently stimulated cell proliferation of OA Ob and also increased phosphorylated p42/44 Erk1/2 and p38 levels. Inactivating antibodies against leptin reduced ALP, OC, CICP and TGF-beta1 levels in OA Ob. Tyrphostin (AG490) and piceatannol (Pce), inhibitors of leptin signaling, reproduced this effect. Inhibition of endogenous leptin levels using siRNA for leptin or inhibiting leptin signaling using siRNA for OB-Rb expression both reduced ALP and OC about 60%. Exogenous leptin addition stimulated ALP, yet this failed to further increase OC or CICP. Conclusions: These results suggest that abnormal production of leptin by OA Ob could be responsible, in part, for the elevated levels of ALP, OC, collagen type 1 and TGF-beta1 observed in these cells compared to normal. Leptin also stimulated cell proliferation, and Erk 1/2 and p38 signaling. Taken together, these data suggest leptin could contribute to abnormal osteoblast function in OA. http://arthritis-research.com/content/12/1/R20 Marie-Solange Mutabaruka Mohamed Aoulad Aissa Aline Delalandre Martin Lavigne Daniel Lajeunesse Arthritis Research & Therapy 2010, 12:R20 2010-02-08T00:00:00Z doi:10.1186/ar2925 Arthritis Research & Therapy 1478-6354 12 R20 2010-02-08T00:00:00Z PDF A food supplement containing fish oils, urtica dioica, Zinc, and Vitamin E (Phytalgic(R)) for osteoarthritis (OA) has now been tested in a placebo-controlled trial for three months and according to the authors has a very large clinical effect, considerably larger than any other known product. Even experts endorsing nutraceuticals for OA symptoms would probably agree that a nutraceutical with an effect size above .5 is rarely seen. Despite our concern about the trial registration taking place after the study was completed, and the likelihood that patients would note the taste of fish, thus leading to detection bias, we consider these data promising although with a high risk of bias. http://arthritis-research.com/content/12/1/105 Robin Christensen Henning Bliddal Arthritis Research & Therapy 2010, 12:105 2010-02-08T00:00:00Z doi:10.1186/ar2909 Arthritis Research & Therapy 1478-6354 12 105 2010-02-08T00:00:00Z PDF IntroductionSynovial fibroblasts from rheumatoid arthritis show resistance to apoptotic stimuli, indicating they may be difficult to treat. To clearly understand these mechanisms of resistance, rheumatoid and osteoarthritis synovial fibroblasts (RASF and OASF) were exposed to endoplasmic reticulum (ER) stress such as thapsigargin, Ca2+-ATPase inhibitor. Methods: Fibroblasts were assessed microscopically for cell viability by trypan blue exclusion and for autophagic cells by LC-3II formation. Caspase-3 activity was measured as aminomethyl-coumarin (AMC) liberated from AC-DEVD-AMC. Immunoblotting was performed to compare protein expression in OASF and RASF. Results: ER stress caused cell death in OASF but not in RASF. Thapsigargin, a Ca2+-ATPase inhibitor, did not change the expression of GRP78, an ER chaperone in OASF and RASF, but induced another ER stress protein, CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) differently, showing high levels in OASF and low levels in RASF. Thapsigargin increased the autophagy response in RASF, with autophagosome formation, beclin expression, and LC3-II conversion. Transfection with beclin siRNA inhibited autophagy and increased the susceptibility to ER stress-induced cell death. On the other hand, CHOP siRNA increased autophagy and improved cell survival, especially in RASF, indicating that CHOP is involved in regulation of autophagy and cell death, but that low expression of CHOP protects RASF from apoptosis. Conclusions: Autophagy induction and CHOP under-expression increases cell resistance against ER stress-induced cell death in fibroblasts from rheumatoid arthritis patients. http://arthritis-research.com/content/12/1/R19 Yong-Joo Shin Song-Hee Han Do-Sung Kim Geum-Hwa Lee Wan-Hee Yoo Yong-Mo Kang Je-Yong Choi Yong Chul Lee Seong Ju Park Seul-Ki Jeong Hyung-Tae Kim Soo-Wan Chae Hyun-Ja Jeong Hyung-Ryong Kim Han-Jung Chae Arthritis Research & Therapy 2010, 12:R19 2010-02-01T00:00:00Z doi:10.1186/ar2921 Arthritis Research & Therapy 1478-6354 12 R19 2010-02-01T00:00:00Z PDF Evaluation of patient reported outcomes, and in particular physical function, have gained increasing importance in research and therapy of patients with rheumatic diseases. Most instruments that are used for that purpose are rigid and suffer from floor and ceiling effects when used in patients whose physical function differs from the average. A new approach to the assessment of physical function uses computerised adaptive testing, by which precision and reliability of the measurement can be achieved for most patients, while even requiring less time for the assessment. Well calibrated and tested item and large item data banks are a prerequisite for this purpose, a process that is summarised in the present report by Bruce and colleagues. http://arthritis-research.com/content/12/1/104 Daniel Aletaha Arthritis Research & Therapy 2010, 12:104 2010-02-01T00:00:00Z doi:10.1186/ar2910 Arthritis Research & Therapy 1478-6354 12 104 2010-02-01T00:00:00Z XML Transforming growth factor beta (TGFβ) is a growth factor with many faces. In our osteoarthritis (OA) research we have found that TGFβ can be protective as well as deleterious for articular cartilage. We postulate that the dual effects of TGFβ on chondrocytes can be explained by the fact that TGFβ can signal via different receptors and related Smad signaling routes. On chondrocytes, TGFβ not only signals via the canonical type I receptor ALK5 but also via the ALK1 receptor. Notably, signaling via ALK5 (Smad2/3 route) results in markedly different chondrocyte responses than ALK1 signaling (Smad1/5/8), and we postulate that the balance between ALK5 and ALK1 expression on chondrocytes will determine the overall effect of TGFβ on these cells. Importantly, signaling via ALK1, but not ALK5, stimulates MMP-13 expression by chondrocytes. In cartilage of ageing mice and in experimental OA models we have found that the ALK1/ALK5 ratio is significantly increased, favoring TGFβ signaling via the Smad1/5/8 route, changes in chondrocyte differentiation and MMP-13 expression. Moreover, human OA cartilage showed a significant correlation between ALK1 and MMP-13 expression. In this paper we summarize concepts in OA, its link with ageing and disturbed growth factor responses, and a potential role of TGFβ signaling in OA development. http://arthritis-research.com/content/12/1/201 Peter van der Kraan Esmeralda Blaney Davidson Wim van den Berg Arthritis Research & Therapy 2010, 12:201 2010-01-29T00:00:00Z doi:10.1186/ar2896 Arthritis Research & Therapy 1478-6354 12 201 2010-01-29T00:00:00Z XML IntroductionNuclear factor-kappaB (NF-kappaB) transcription factor regulates several cell signaling pathways, such as differentiation and inflammation, which are both altered in osteoarthritis. Inhibitor kappaB kinase (IKK)alpha and IKKbeta are kinases involved in the activation of the NF-kappaB transcription factor. The aim of the present study was to determine the effects of glucosamine (GlcN), which is administered in the treatment of osteoarthritis, and of its 2-(N-Acetyl)-L-phenylalanylamido-2-deoxy-beta-D-glucose (NAPA) derivative on IKK kinases and, consequently, on NF-kappaB activation in human chondrocytes. Methods: The human chondrosarcoma cell line HTB-94 and human primary chondrocytes were stimulated with tumor necrosis factor (TNF)alpha after pre-treatment with GlcN or NAPA. Gene mRNA expression level was evaluated by real time-PCR. IkappaBalpha phosphorylation and p65 nuclear re-localization were analyzed by Western blotting, IKKalpha nuclear re-localization was also investigated by immunocytochemistry and Western blotting. IKK kinase activity was studied by in vitro kinase assay. Results: After TNFalpha stimulation, the mRNA expression level of some of the genes under NF-kappaB control, such as interleukin (IL)-6 and IL-8, increased, while treatment with GlcN and NAPA reverted the effect. We investigated the possibility that GlcN and NAPA inhibit IKK kinase activity and found that NAPA inhibits the IKKalpha kinase activity, whereas GlcN does not. Interestingly, both GlcN and NAPA inhibit IKKalpha nuclear re-localization. Conclusions: Our results demonstrate that glucosamine and its peptidyl-derivative can interfere with NF-kappaB signaling pathway by inhibiting IKKalpha activity in human chondrocytes. However, the mechanism of action of the two molecules is not completely overlapping. While NAPA can both specifically inhibit the IKKalpha kinase activity and IKKalpha nuclear re-localization, GlcN only acts on IKKalpha nuclear re-localization. ${item.link} Anna Scotto d'Abusco Laura Politi Cesare Giordano Roberto Scandurra Arthritis Research & Therapy 2010, 12:R18 2010-01-29T00:00:00Z ${item.identifier} Arthritis Research & Therapy 1478-6354 12 R18 2010-01-29T00:00:00Z PDF IntroductionFibromyalgia is a chronic pain syndrome with unknown etiology. Recent studies have shown some evidence demonstrating that oxidative stress may have a role in the pathophysiology of fibromyalgia. However, it is still not clear whether oxidative stress is the cause or the effect of the abnormalities documented in fibromyalgia. Furthermore, the role of mitochondria in the redox imbalance reported in fibromyalgia is also controversial. We undertook this study to investigate the role of mitochondrial dysfunction, oxidative stress and mitophagy in fibromyalgia. Methods: We studied 20 patients (2 males and 18 females) recruited from the database of the Sevillian Fibromyalgia Association and 10 healthy controls. We evaluated mitochondrial function in blood mononuclear cells from fibromyalgia patients measuring coenzyme Q10 levels by high performance liquid chromatography (HPLC), and mitochondrial membrane potential by flow cytometry. Oxidative stress was determined by measuring mitochondrial superoxide production by MitoSOXTM, and lipid peroxidation in blood mononuclear cells and plasma from fibromyalgia patients. Autophagy activation was evaluated by quantifying the fluorescence intensity of LysoTrackerTM Red staining of blood mononuclear cells. Mitophagy was confirmed by measuring citrate synthase activity and electron microscopy examination of blood mononuclear cells. Results: We found reduced levels of coenzyme Q10, decreased mitochondrial membrane potential, increased level of mitochondrial superoxide in blood mononuclear cells, and increased levels of lipid peroxidation in both blood mononuclear cells and plasma from fibromyalgia patients. Mitochondrial dysfunction was also associated with increased expression of autophagic genes and the elimination of dysfunctional mitochondria by mitophagy. Conclusions: These findings may support the role of oxidative stress and mitophagy in the pathophysiology of fibromyalgia. ${item.link} Mario Cordero Manuel De Miguel Ana Moreno Fernandez Ines Carmona Lopez Juan Garrido Maraver David Cotan Lourdes Gomez Izquierdo Pablo Bonal Francisco Campa Pedro Bullon Placido Navas Jose Sanchez Alcazar Arthritis Research & Therapy 2010, 12:R17 2010-01-28T00:00:00Z ${item.identifier} Arthritis Research & Therapy 1478-6354 12 R17 2010-01-28T00:00:00Z PDF IntroductionThe objective was to evaluate the changes in S100A8 S100A9, and their complex (S100A8/S100A9) in cartilage during the onset of osteoarthritis (OA) as opposed to inflammatory arthritis. Methods: S100A8 and S100A9 protein localization were determined in antigen-induced inflammatory arthritis in mice, mouse femoral head cartilage explants stimulated with interleukin-1 (IL-1), and in surgically-induced OA in mice. Micro-array expression profiling of all S100 proteins in cartilage was evaluated at different times after initiation of degradation in femoral head explant cultures stimulated with IL-1 and surgically-induced OA. The effect of S100A8, S100A9 or the complex on the expression of aggrecan (Acan), collagen II (Col2a1), disintegrin and metalloproteases with thrombospondin motifs (Adamts1, Adamts 4 & Adamts 5), matrix metalloproteases (Mmp1, Mmp3, Mmp13 & Mmp14) and tissue inhibitors of metalloproteinases (Timp1, Timp2 & Timp3), by primary adult ovine articular chondrocytes was determined using real time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results: Stimulation with IL-1 increased chondrocyte S100a8 and S100a9 mRNA and protein levels. There was increased chondrocyte mRNA expression of S100a8 and S100a9 in early but not late mouse OA. However, loss of the S100A8 staining in chondrocytes occurred as mouse OA progressed, in contrast to the positive reactivity for both S100A8 and S100A9 in chondrocytes in inflammatory arthritis in mice. Homodimeric S100A8 and S100A9, but not the heterodimeric complex, significantly upregulated chondrocyte Adamts1, Adamts4 and Adamts 5, Mmp1, Mmp3 and Mmp13 gene expression, while collagen II and aggrecan mRNAs were significantly decreased. Conclusions: Chondrocyte derived S100A8 and S100A9 may have a sustained role in cartilage degradation in inflammatory arthritis. In contrast, while these proteins may have a role in initiating early cartilage degradation in OA by upregulating MMPs and aggrecanases, their reduced expression in late stages of OA suggests they do not have an ongoing role in cartilage degradation in this non-inflammatory arthropathy. http://arthritis-research.com/content/12/1/R16 Hala Zreiqat Daniele Belluoccio Margaret Smith Richard Wilson Lynn Rowley Katie Jones Yogambha Ramaswamy Thomas Vogl Johannes Roth John Bateman Christopher Little Arthritis Research & Therapy 2010, 12:R16 2010-01-27T00:00:00Z doi:10.1186/ar2917 Arthritis Research & Therapy 1478-6354 12 R16 2010-01-27T00:00:00Z PDF IntroductionThe synovium is a major target tissue in chronic arthritis and is intensively studied at the cellular and molecular level. The aim of this study was to develop flow cytometry for the quantitative analysis of synovial cell populations pre and post culture and to characterize mesenchymal cell populations residing in the inflammatory synovium. Methods: Knee synovium biopsies from 39 patients with chronic arthritis and from 15 controls were treated in a short, standardized tissue digestion procedure. Stored thawed digests were routinely analyzed with flow cytometry including live-dead staining and use of the markers CD45, CD3, CD14, CD20, CD34, CD73, CD105, CD90, CD146, CD163 and HLA-DR to distinguish inflammatory and stromal cells. The influence of the digestion method on the detection of the different surface markers was studied separately. In addition, we studied the presence of a specific cell population hypothesized to be mesenchymal stem cells (MSC) based on the CD271 marker. Cell expansion cultures were set up and a MSC-related surface marker profile in passages 3 and 6 was obtained. Immunohistochemistry for CD34 and von Willebrand factor (vWF) was done to obtain additional data on synovium vascularity. Results: The cell yield and viability normalized to tissue weight were significantly higher in inflammatory arthritis than in controls. Within the hematopoietic CD45-positive populations, we found no differences in relative amounts of macrophages, T-lymphocytes and B-lymphocytes between patient groups. Within the CD45-negative cells, more CD34-positive cells were seen in controls than in arthritis patients. In arthritis samples a small CD271 positive population was detected. Culture expanded cells were found to fulfill the multipotent mesenchymal stromal cell marker profile, except for CD34 negativity. Detection of peripheral blood macrophage and B-cell markers was decreased after enzymatic exposure and mechanical forces, respectively, but stromal markers were not affected. Conclusions: Flow cytometry can distinguish synovial cell populations in tissue digests. The preparation method can influence the detection levels of macrophage and B-cell populations. However, stromal cell markers seem not affected and quantification is possible, supporting flow cytometry tissue analysis as a tool to study these cell populations in arthritis. http://arthritis-research.com/content/12/1/R15 Kristel Van Landuyt Elena Jones Dennis McGonagle Frank Luyten Rik Lories Arthritis Research & Therapy 2010, 12:R15 2010-01-27T00:00:00Z doi:10.1186/ar2916 Arthritis Research & Therapy 1478-6354 12 R15 2010-01-27T00:00:00Z PDF