osteoprotegerin and Arthritis--Rheumatoid

Nuclear Factor Kappa-Β (NF-kB) is recognized as one of the main inflammatory pathways in the Autoimmune Disease (AD) Rheumatoid Arthritis (RA), which exhibits high levels of inflammatory cytokines such as IL-1, TNFa and IL-6 linked to bone erosion and disease progression. NF-kB is also the most studied pathophysiological mechanism in RA, however, over the last few decades, a more recently discovered Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL), also linked to NF-kB activation and bone erosion, has been the topic of interest for research in the area of AD management. As the non-discriminative long term suppression of the NF-kB pathway by pharmacological agents in the management of RA has been linked with a number of side effects and with the discovery of the RANKL mechanism, which may present a more targeted approach to the management of the AD, there has been renewed interest in research on the potential impact of nutritional interventions influencing the NF-kB pathway, RANKL as well as RA disease outcomes. Existing research highlights the potential utility of nutrients such as Omega 3 and Vitamin D, which may lower NF-kB activation in RA. There is, however, a gap in the knowledge of the effects of nutritional interventions on pathophysiological mechanisms contributing to RA and a more robust systematic analysis of whether nutrients or specific vitamins can have an effect on the NF-kB and RANKL main drivers of pathology in RA. Findings from this study suggest the potential of Vitamin D supplementation in lowering the levels of RANKL and related markers/cytokines such as Th17 cell levels, OPG/RANKL ratio and CXCL10 pathway, which may present as a viable nutrition intervention for the management of RA. The methodology of this review involved a Systematic Search of the Literature with a Critical Appraisal of papers. It incorporated three tranche searches of 1. review, 2. animal/in vitro and 3. intervention peer reviewed research published in the last 10 years, resulting in a total of 119 papers. Results provide an overview of the NF-kB pathway, a detailed mechanistic examination of the Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL) which is linked to bone erosion, and finally a review of nutritional interventions relating to this mechanism of pathophysiology. The accepted papers were critically appraised using SIGN50 for human studies and the ARRIVE guidelines for animal studies; the narrative was and the extracted information cod

Topics: Animals; Arthritis, Rheumatoid; Humans; Ligands; NF-kappa B; Osteoclasts; Osteoprotegerin; RANK Ligand

The process of bone remodeling is the result of the regulated balance between bone cell populations, namely bone-forming osteoblasts, bone-resorbing osteoclasts, and the osteocyte, the mechanosensory cell type. Osteoclasts derived from the hematopoietic stem cell lineage are the principal cells involved in bone resorption. In osteolytic diseases such as rheumatoid arthritis, periodontitis, and osteoporosis, the balance is lost and changes in favor of bone resorption. Therefore, it is vital to elucidate the mechanisms of osteoclast formation and bone resorption. It has been reported that osteocytes express Receptor activator of nuclear factor κΒ ligand (RANKL), an essential factor for osteoclast formation. RANKL secreted by osteocytes is the most important factor for physiologically supported osteoclast formation in the developing skeleton and in pathological bone resorption such as experimental periodontal bone loss. TNF-α directly enhances RANKL expression in osteocytes and promotes osteoclast formation. Moreover, TNF-α enhances sclerostin expression in osteocytes, which also increases osteoclast formation. These findings suggest that osteocyte-related cytokines act directly to enhance osteoclast formation and bone resorption. In this review, we outline the most recent knowledge concerning bone resorption-related cytokines and discuss the osteocyte as the master regulator of bone resorption and effector in osteoclast formation.

Topics: Adaptor Proteins, Signal Transducing; Animals; Arthritis, Rheumatoid; Bone Resorption; Cytokines; Gene Expression Regulation, Developmental; Humans; Intercellular Signaling Peptides and Proteins; Osteoclasts; Osteocytes; Osteogenesis; Osteoporosis; Osteoprotegerin; Periodontitis; RANK Ligand; Signal Transduction

Currently published data regarding the potential role of osteoprotegerin (OPG), osteocalcin (OCN) and osteopontin (OPN) for the discrimination between rheumatoid arthritis (RA) and osteoarthritis (OA) are contradictory. To derive a more precise evaluation, a meta-analysis was performed.. Published literatures comparing plasma/serum OPG, OCN and OPN levels between RA group and OA controls were searched in PubMed, Embase and the Cochrane Library. The Newcastle-Ottawa Scale was used to assess the study quality. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by random-effect model analysis. Heterogeneity test was performed by the Q statistic and quantified using I. Nine studies including 438 RA patients and 255 OA patients were finally incorporated in the meta-analysis after examining title, type, abstracts and full text. The results showed that RA patients had higher plasma/serum OPN (pooled SMD = -2.57, 95% CI = -4.72 to -0.41) levels when compared to OA patients. No significant difference in plasma/serum OPG (pooled SMD = -0.29, 95% CI = -1.07‒0.49) and OCN (pooled SMD = -0.09, 95% CI = -0.48‒0.31) levels were found between RA patients and OA patients. Subgroup analysis indicated that plasma/serum OPG levels had no significant differences between RA patients and OA patients in Europe and Asian.. Overall, there is no significant difference in circulating OPG and OCN levels between RA patients and OA patients. However, plasma/serum OPN level is significantly higher in RA patients compared with OA patients.

Topics: Arthritis, Rheumatoid; Biomarkers; Diagnosis, Differential; Humans; Osteoarthritis; Osteocalcin; Osteopontin; Osteoprotegerin; Prognosis; Publication Bias

This study aimed to systemically review the evidence regarding the relationship between the circulating blood osteoprotegerin (OPG) level and rheumatoid arthritis (RA), as well as the potential influential factors. Research related to plasma/serum OPG levels in RA patients and healthy controls were gathered using PubMed, EMBASE, and The Cochrane Library database (up to Jan. 1, 2017). Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by fixed-effects or random-effect model analysis. Heterogeneity test was performed by the Q statistic and quantified using I

Topics: Adult; Aged; Arthritis, Rheumatoid; Body Mass Index; Case-Control Studies; Cross-Sectional Studies; Ethnicity; Female; Humans; Linear Models; Male; Middle Aged; Osteoprotegerin; Severity of Illness Index; Time Factors

Disorders of bone tissue metabolism and increased frequency of cardiovascular diseases are among the well-known, extra-articular complications of rheumatoid arthritis (ra). The mechanisms leading to local and generalized loss of bone tissue as well as those promoting calcification of vessels are similar. Recently, a great interest has aroused among the studies related to the meaning of the RANKL/RANK/OPG system and the Wnt/β-catenin signaling pathway, as biological links between the bone and vascular systems. In the course of ra, lowering of the mineral density of bones and intensification of vascular calcification seem to be associated with the increase of plasma concentration of osteoprotegerin (OPG) and sclerostin - the regulatory proteins of the RANKL/RANK/OPG system and the Wnt/β-catenin pathway. Molecular mechanisms associated with the osteoblasts' activation and repression of bone resorption in the future can become the target of a precise, combination therapy in osteoporosis and calcification changes. The article presents the role of the RANKL/RANK/ OPG system and the Wnt/β-catenin pathway in the pathogenesis of disorders of bone tissue metabolism and calcification of vessels in ra, with particular emphasis on the role of OPG and sclerostin.

Topics: Adaptor Proteins, Signal Transducing; Arthritis, Rheumatoid; Bone Morphogenetic Proteins; Genetic Markers; Humans; Osteoporosis; Osteoprotegerin; Signal Transduction; Vascular Calcification

The immune and skeletal systems share a variety of molecules, including cytokines, chemokines, hormones, receptors, and transcription factors. Bone cells interact with immune cells under physiological and pathological conditions. Osteoimmunology was created as a new interdisciplinary field in large part to highlight the shared molecules and reciprocal interactions between the two systems in both heath and disease. Receptor activator of NF-κB ligand (RANKL) plays an essential role not only in the development of immune organs and bones, but also in autoimmune diseases affecting bone, thus effectively comprising the molecule that links the two systems. Here we review the function, gene regulation, and signal transduction of osteoimmune molecules, including RANKL, in the context of osteoclastogenesis as well as multiple other regulatory functions. Osteoimmunology has become indispensable for understanding the pathogenesis of a number of diseases such as rheumatoid arthritis (RA). We review the various osteoimmune pathologies, including the bone destruction in RA, in which pathogenic helper T cell subsets [such as IL-17-expressing helper T (Th17) cells] induce bone erosion through aberrant RANKL expression. We also focus on cellular interactions and the identification of the communication factors in the bone marrow, discussing the contribution of bone cells to the maintenance and regulation of hematopoietic stem and progenitors cells. Thus the time has come for a basic reappraisal of the framework for understanding both the immune and bone systems. The concept of a unified osteoimmune system will be absolutely indispensable for basic and translational approaches to diseases related to bone and/or the immune system.

Topics: Allergy and Immunology; Animals; Arthritis, Rheumatoid; Cell Communication; Hematopoietic Stem Cells; Humans; Immunity; Osteoclasts; Osteology; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction; Skeleton

We undertook this study to assess the association between osteoprotegerin (OPG) gene polymorphisms and rheumatoid arthritis (RA) susceptibility.. English language databases of PubMed Medline and OVID EMBASE and Chinese databases of China National Knowledge Infrastructure, Chinese Biomedical Literature Database and Wanfang were searched to identify case-control studies studied the relationship between OPG gene polymorphisms and RA susceptibility. Two reviewers separately and repeatedly screened searched studies according to study selection criteria and collected data. Data analyses of five comparison models-allelic model, heterozygote model, homozygote model, dominant model and recessive model-were conducted in Review Manager Software 5.1.. A total of five studies including 1713 RA cases and 1845 controls were eligible in this meta-analysis. Single nucleotide polymorphisms (SNPs), rs3102735 T/C or A/G, rs2073618 G/C and rs3134069 T/G, of OPG gene were studied. Data from five studies of SNPs rs3102735 were OR = 1.22, 95% CI 0.86-1.73, OR = 1.06, 95% CI 0.86-1.32, OR = 1.79, 95% CI 0.65-4.89, OR = 1.16, 95% CI 0.85-1.59, OR = 1.73, 95% CI 0.67-4.46, respectively, for the five comparison models in order. For SNPs rs2073618, results derived from three studies were OR = 1.06, 95% CI 0.95-1.19, OR = 1.11, 95% CI 0.94-1.31, OR = 1.09, 95% CI 0.84-1.42, OR = 1.10, 95% CI 0.94-1.30, OR = 1.04, 95% CI 0.84-1.30, respectively. With respect to SNPs rs3134069, only one study assessed the associations, reporting no statistically significant results among the five comparison models.. SNPs rs3102735, rs2073618 and rs3134069 of OPG gene polymorphisms are not susceptibility factors of RA based on currently available evidence.

Topics: Alleles; Arthritis, Rheumatoid; Case-Control Studies; Genetic Association Studies; Genetic Predisposition to Disease; Heterozygote; Homozygote; Humans; Osteoprotegerin; Polymorphism, Single Nucleotide

Mesenchymal stem cells (MSCs) possess multipotent capacity and exhibit immunoregulatory properties. In particular, MSCs can be easily isolated from various organs, can differentiate into various types of cells and generate regulatory T cells. Using human MSC derived from bone marrow and adipose tissue, we have clarified the following novel findings in vitro. 1) MSCs differentiated into osteoblasts or osteocytes under osteoblast-conditioned medium including the inflammatory stimuli such as IL-1. 2) The combination of IL-6 and soluble IL-6 receptor induced differentiation of MSCs to chondrocyte, whereas IL-17 inhibited their differentiation. 3) MSCs highly produced osteoprotegerin and inhibited osteoclastogenesis. Furthermore, we developed a local delivery system of MSCs by using nano-fiber scaffold. MSCs seeded on nano-fiber scaffold suppressed arthritis and bone destruction due to inhibition of systemic inflammatory reaction and immune response by suppressing T cell proliferation and reducing anti-type II collagen antibody production in vivo. Thus, our data may serve as a new strategy for MSC-based therapy in inflammatory diseases and an alternative delivery method for the treatment of destruction of bone and joints.

Topics: Adipose Tissue; Antibody Formation; Arthritis, Rheumatoid; Bone Marrow Cells; Cell Differentiation; Collagen Type II; Culture Media; Humans; Interleukin-1; Interleukin-17; Interleukin-2; Interleukin-6; Lymphocyte Activation; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Nanofibers; Osteoblasts; Osteocytes; Osteoprotegerin; Receptors, Interleukin-6; T-Lymphocytes; Tissue Scaffolds

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovitis and bone destruction leading to irreversible joint deformity. The development of a novel treatment for RA aiming at joint repair is necessary. Recently, mesenchymal stem cells (MSCs) have been widely studied as a new therapeutic tool for the treatment of RA, due to their multipotency and also their immunosuppressive properties. We show here that MSCs inhibit osteoclast differentiation depending on the constitutive production of osteoprotegerin, a decoy receptor of receptor activator of nuclear factor kappa-B ligand (RANKL). Our results further indicate that MSCs are useful in RA treatment by preventing the progression of bone damage by inhibiting osteoclast differentiation. In addition, MSCs are likely to play important roles in bone metabolism and maintenance of joint formation. In conclusion, MSC is a promising tool for both anti-inflammation and bone repair for RA patients.

Topics: Arthritis, Rheumatoid; Humans; Mesenchymal Stem Cells; Osteoclasts; Osteoprotegerin

It is now well acknowledged that the immune and skeletal systems interact and affect one another during developmental physiology and pathology. With the aid of modern conditional gene targeting and transgenic technologies, this field of interdisciplinary research, known as osteoimmunology, is rapidly advancing. Numerous bone phenotypes have been described in immune-compromised gene-deficient mice and, albeit to a lesser extent, immune deficiencies exist in osteo-compromised gene-deficient mice, suggesting that bone cells themselves actually regulate the development of immune cells directly. In this review, I discuss the essential role of key cytokines, signalling transduction pathways and transcription factors during immune and bone development, and how pathology driven dysregulation of these shared mechanisms can lead to clinical manifestations. Diseases that are within the remit of osteoimmunology continue to cause significant morbidity, for example, rheumatoid arthritis, osteoporosis, multiple myeloma and breast/prostate cancer. The complexity and overlapping cellular and molecular interactions between the immune and bone tissues, mean that despite fervent research of these diseases, it remains a major challenge to discover therapeutics that can specifically target one system without detrimentally affecting the other.

Topics: Animals; Arthritis, Rheumatoid; Bone and Bones; Calcium Signaling; Female; Humans; Male; Mice; Models, Biological; NFATC Transcription Factors; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction; Stem Cell Niche; T-Lymphocyte Subsets

Receptor activator of nuclear factor kappa B ligand (RANKL) and its natural antagonist, osteoprotegerin (OPG), are, respectively, an indispensable factor and a potent inhibitor for osteoclast differentiation, activity, and survival. The development of a human monoclonal antibody to RANKL, denosumab, constitutes a novel approach to prevent fragility fractures in osteoporosis, skeletal complications of malignancy, and potentially bone erosions in rheumatoid arthritis (RA). In addition to being expressed by osteoblasts, RANKL is abundantly produced by activated T cells, and synoviocytes in RA, whereas its receptor, RANK, is also expressed by monocytes/macrophages and dendritic cells. However, in preclinical and clinical studies of RA-including patients with some degree of immunosuppression-RANKL inhibitors did not significantly alter inflammatory processes. RANKL, RANK, and OPG deficiency in murine models highlights the important role of this pathway in the development and maturation of the immune system in rodents, including functions of T and/or B cells, whereas OPG overexpression in mice and rats seems innocuous with regard to immunity. In contrast, loss-of-function mutations in humans have more limited effects on immune cells. In clinical studies, the overall rate of infections, cancer, and death was similar with denosumab and placebo. Nevertheless, the risk of severe infections and cancer in some specific tissues remains to be carefully scrutinized.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Arthritis, Rheumatoid; B-Lymphocytes; Bone Resorption; Denosumab; Female; Humans; Infections; Mice; Neoplasms; Osteoblasts; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Rats; Receptor Activator of Nuclear Factor-kappa B; T-Lymphocytes; Tumor Necrosis Factor-alpha

Osteoimmunology is defined as the research area focusing on the crosstalk between the immune system and the muskoskeletal system. After nearly a decade of research, we are now beginning to understand the basic principles of this crosstalk. It seems that almost all immune cells are capable of communicating with osteoblasts, osteoclasts, and their respective progenitors - and vice versa. Diseases that fall into the category of osteoimmunology including osteoporosis, rheumatoid arthritis, and periodontal disease are of particular significance considering their implications in quality of life, their increased incidence in the population, and socioeconomic issues. To better understand the underlying pathogenesis, the main pathways of the crosstalk between the immune system and the muskoskeletal system need to be uncovered. Our current understanding has already provided the scientific basis for the development of targeted therapies. However, the challenge of future studies is to further decipher this crosstalk at cellular and molecular levels.

Topics: Arthritis, Rheumatoid; Bone and Bones; Bone Diseases; Cell Communication; Hematopoietic Stem Cells; Humans; Immunity, Cellular; Osteoblasts; Osteoclasts; Osteoporosis; Osteoprotegerin; Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; T-Lymphocytes

We should consider not only controlling disease activity using DMARDs and biologics as a matter of course, but also preventing against joint destruction, in the treatment for rheumatoid arthritis. Although we can indirectly regulate bone erosion via controlling disease activity, the osteoclast-targeting therapy might be more effective to stop joint destruction. We are waiting for new drugs directly targeting osteoclasts, such as OPG which is the natural inhibitor of RANKL, or cathepsin K inhibitor which reduces degeneration of bone matrix.

Topics: Animals; Arthritis, Rheumatoid; Azepines; Biphenyl Compounds; Cathepsin K; Cathepsins; Cell Differentiation; Drug Design; Humans; Joints; Osteoclasts; Osteoprotegerin; Pyridines; RANK Ligand; Sulfones

The pathway of the receptor activator of the nuclear factor kappaB ligand (RANKL), RANK and osteoprotegerin (OPG) plays a central role in coupling bone formation and resorption during normal bone turnover and in a wide spectrum of diseases characterized by disturbed bone remodeling, increased bone resorption and bone destruction (osteoporosis, Paget's disease of bone, rheumatoid arthritis [RA], metastatic bone disease). Clinical trials indicate that denosumab, a RANKL-specific recombinant humanized monoclonal antibody, is effective in suppressing bone resorption, resulting in increase in bone mineral density (BMD) in post-menopausal women with low BMD, and has the potential to prevent progression of erosions in RA and of skeletal-related events in metastatic bone disease. The effects on fracture reduction in postmenopausal osteoporosis are awaited from the recently finished FREEDOM study. In clinical trials with denosumab, overall adverse events were similar to placebo or comparators, indicating a favorable safety profile in these diseases, which until now have been available up to 4 years, but data on long-term safety will be needed.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Arthritis, Rheumatoid; Bone Density; Bone Remodeling; Bone Resorption; Denosumab; Female; Fractures, Bone; Humans; Middle Aged; Osteoporosis, Postmenopausal; Osteoprotegerin; RANK Ligand

Bone integrity is maintained through a balance between bone formation and bone resorption, and osteoclasts are primary cells involved in bone resorption. Recent studies have revealed an essential role of macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL) in the development of osteoclasts, and detailed molecular cascades that induce osteoclast differentiation, activation and apoptosis have been clarified. Osteoclasts are involved in various pathologic conditions, such as osteoporosis, rheumatoid arthritis and tumor-induced bone disease, which are characterized by abnormal bone resorption, and the finding of RANKL has provided us a good therapeutic target for such pathologic conditions.

Topics: Animals; Arthritis, Rheumatoid; Bone Diseases; Bone Resorption; Humans; Neoplasms; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction

Receptor activator of nuclear factor XB ligand (RANKL) belongs to the TNF superfamily of cytokines. It plays a key role in osteoclastogenesis, activation, and survival of osteoclasts. The differentiation of macrophage/monocyte-like cells into osteoclasts critically depends on the binding of monocyte-colony stimulating factor (M-CSF) and RANKL by their respective plasma-membrane receptors, c-Fms and RANK. Osteoprotegerin (OPG), a soluble protein of the TNF receptor superfamily that is synthesized mainly by osteoblasts, is a decoy receptor that binds RANKL. In this way OPG competes with RANK what results in the inhibition of osteoclastogenesis and bone resorption. It has been shown that the RANKL/OPG ratio may determine the delicate balance between bone resorption and synthesis. Under normal conditions RANKL is mainly produced by osteoblasts and bone marrow stromal cells. However, in many pathological conditions such as rheumatoid arthritis (RA) and neoplastic osteolysis RANKL is also produced by T and B lymphocytes, macrophages/ monocytes, fibroblasts, synoviocytes, and megakaryocytes. In RA osteolysis is promoted not only by M-CSF and RANKL, but also by other cytokines (TNF, IL-1beta, IL-6, IL-7, IL-11, IL-15, IL-17, IL-18), hormones (PTH, PTH-rP, corticosteroids), and prostaglandin E2. On the contrary, OPG, interferon gamma, IL-4, TGF-beta, bifosfonians, and estrogens inhibit RA-associated osteoclastogenesis. Recently, therapeutics for pathological bone destruction targeting RANKL pathways have been used for the treatment of postmenopausal osteoporosis.

Topics: Arthritis, Rheumatoid; Bone Resorption; Humans; Ligands; Osteoblasts; Osteoclasts; Osteoprotegerin; RANK Ligand; Tumor Necrosis Factors

Topics: Acid Phosphatase; Alkaline Phosphatase; Amino Acids; Arthritis, Rheumatoid; Biomarkers; Bone Resorption; Collagen Type I; Humans; Isoenzymes; Osteocalcin; Osteogenesis; Osteoporosis; Osteoprotegerin; Peptide Fragments; Peptides; Procollagen; RANK Ligand; Tartrate-Resistant Acid Phosphatase

The current studies of apoptosis in rheumatoid arthritis (RA) suggest that the TNF ligand-receptor superfamily (TNFRsF) molecules, downstream pathways (activation of proapoptosis or anti-apoptosis pathway), cell types (lymphocytes and synovial fibroblast), and the mechanism that triggers apoptosis (tolerance induction-related, downmodulation of inflammation-related, or DNA damage-related) all exhibit a capability to determine the induction or prevention of RA. This series of defects at different levels and in different cells have been shown to lead to T cell and synovial hyperproliferation, defective apoptosis, excessive apoptosis, or bone erosion. In this chapter, we summarize the available knowledge of the regulation of TNFRsF and their likely pathogenic roles in RA to help identify candidate target cells and target molecules for delivery of gene constructs to modulate apoptosis to prevent the development of RA in both humans and mice.

Topics: Apoptosis; Arthritis, Rheumatoid; Autoimmunity; Carrier Proteins; Cell Proliferation; Glycoproteins; Humans; Membrane Glycoproteins; Osteoprotegerin; OX40 Ligand; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, OX40; Receptors, Tumor Necrosis Factor; Signal Transduction; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors

Rheumatoid arthritis is characterized by the presence of inflammatory synovitis and destruction of joint cartilage and bone. Tissue proteinases released by synovia, chondrocytes and pannus can cause cartilage destruction and cytokine-activated osteoclasts have been implicated in bone erosions. Rheumatoid arthritis synovial tissues produce a variety of cytokines and growth factors that induce monocyte differentiation to osteoclasts and their proliferation, activation and longer survival in tissues. More recently, a major role in bone erosion has been attributed to the receptor activator of nuclear factor kappa B ligand (RANKL) released by activated lymphocytes and osteoblasts. In fact, osteoclasts are markedly activated after RANKL binding to the cognate RANK expressed on the surface of these cells. RANKL expression can be upregulated by bone-resorbing factors such as glucocorticoids, vitamin D3, interleukin 1 (IL-1), IL-6, IL-11, IL-17, tumor necrosis factor-alpha, prostaglandin E2, or parathyroid hormone-related peptide. Supporting this idea, inhibition of RANKL by osteoprotegerin, a natural soluble RANKL receptor, prevents bone loss in experimental models. Tumor growth factor-beta released from bone during active bone resorption has been suggested as one feedback mechanism for upregulating osteoprotegerin and estrogen can increase its production on osteoblasts. Modulation of these systems provides the opportunity to inhibit bone loss and deformity in chronic arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Chronic Disease; Cytokines; Disease Models, Animal; Glycoproteins; Humans; Membrane Glycoproteins; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Identification of RANKL/ODF (receptor activator of NF-kappaB ligand/osteoclast differentiation factor), RANK(receptor activator of NF-kappaB) and OPG/OCIF(osteoprotegerin/ osteoclastogenesis inhibitory factor) revealed the mechanisms regulating osteoclast differentiation and function. RANKL-RANK signaling is essential for the physiological osteoclast development and plays a major role in the pathological bone destruction. OPG and anti-RANKL antibody act as a specific inhibitor of RANKL and are useful and applicable to osteoporosis and rheumatoid arthritis.

Topics: Animals; Antibodies; Arthritis, Rheumatoid; Carrier Proteins; Glycoproteins; Humans; In Vitro Techniques; Membrane Glycoproteins; Mice; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Animals; Arthritis, Rheumatoid; Carrier Proteins; Disease Models, Animal; Glycoproteins; Membrane Glycoproteins; Osteoprotegerin; RANK Ligand; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Periodontitis and rheumatoid arthritis (RA) appear to share many pathologic features. In this review, the common pathologic mechanisms of these two common chronic conditions are explored. Emerging evidence now suggests a strong relationship between the extent and severity of periodontal disease and RA. While this relationship is unlikely to be causal, it is clear that individuals with advanced RA are more likely to experience more significant periodontal problems compared to their non-RA counterparts, and vice versa. A case is made that these two diseases could be very closely related through common underlying dysfunction of fundamental inflammatory mechanisms. The nature of such dysfunction is still unknown. Nonetheless, there is accruing evidence to support the notion that both conditions manifest as a result of an imbalance between proinflammatory and anti-inflammatory cytokines. As a result, new treatment strategies are expected to emerge for both diseases that may target the inhibition of proinflammatory cytokines and destructive proteases. The clinical implications of the current data dictate that patients with RA should be carefully screened for their periodontal status.

Topics: Animals; Antirheumatic Agents; Arthritis, Rheumatoid; Carrier Proteins; Cytokines; Genetic Predisposition to Disease; Glycoproteins; Humans; Immunosuppressive Agents; Inflammation Mediators; Membrane Glycoproteins; Osteoclasts; Osteoprotegerin; Periodontitis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Osteoclasts are primary cells for physiological and pathological bone resorption, and receptor activator of nuclear factor-kappaB ligand (RANKL) is critically involved in the differentiation, activation, and survival of these cells. Recently, therapeutics for pathological bone destruction targeting RANKL pathways has attracted a great deal of attention. Herein, we review the recent advances in the research on osteoclast biology and discuss the advantages and disadvantages of anti-RANKL therapies.

Topics: Animals; Apoptosis; Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Cell Differentiation; Glycoproteins; Humans; Membrane Glycoproteins; NF-kappa B; Osteoclasts; Osteoporosis; Osteoprotegerin; Periodontal Diseases; Proto-Oncogene Proteins c-bcl-2; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction; TNF Receptor-Associated Factor 6

Rheumatoid arthritis, juvenile idiopathic arthritis, the seronegative spondyloarthropathies including psoriatic arthritis, and systemic lupus erythematosus are all examples of rheumatic diseases in which inflammation is associated with skeletal pathology. Although some of the mechanisms of skeletal remodeling are shared among these diseases, each disease has a unique impact on articular bone or on the axial or appendicular skeleton. Studies in human disease and in animal models of arthritis have identified the osteoclast as the predominant cell type mediating bone loss in arthritis. Many of the cytokines and growth factors implicated in the inflammatory processes in rheumatic diseases have also been demonstrated to impact osteoclast differentiation and function either directly, by acting on cells of the osteoclast-lineage, or indirectly, by acting on other cell types to modulate expression of the key osteoclastogenic factor receptor activator of nuclear factor (NF) kappaB ligand (RANKL) and/or its inhibitor osteoprotegerin (OPG). Further elucidation of the mechanisms responsible for inflammation-induced bone loss will potentially lead to the identification of novel therapeutic strategies for the prevention of bone loss in these diseases. In this review, we provide an overview of the cell types, inflammatory mediators, and mechanisms that are implicated in bone loss and new bone formation in inflammatory joint diseases.

Topics: Animals; Arthritis, Juvenile; Arthritis, Rheumatoid; Bone and Bones; Bone Remodeling; Bone Resorption; Carrier Proteins; Cytokines; Glycoproteins; Humans; Inflammation; Lupus Erythematosus, Systemic; Membrane Glycoproteins; Osteoclasts; Osteogenesis; Osteoprotegerin; Parathyroid Hormone-Related Protein; Prostaglandins; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction; Spondylarthropathies

Osteoprotegerin (OPG), a member of the TNF-receptor family expressed by osteoblasts, has documented effects on the regulation of bone metabolism. OPG inhibits bone resorption and binds with strong affinity to its ligand RANKL, thereby preventing RANKL from binding to its receptor RANK. This system is regulated by calcium-modifying hormones. OPG may also be pivotal in modulating the immune system. RANKL-deficient mice exhibit both severe immunological abnormalities and osteopetrosis, and activated T cells express RANKL mRNA. RANKL secretion by activated T cells may induce osteoclastogenesis via a mechanism enhanced by several cytokines (TNF-alpha, IL-1, and IL-17) that promote both inflammation and bone resorption. Conversely, this mechanism is inhibited by OPG, IL-4, and IL-10, which have antiinflammatory effects and inhibit osteoclast formation. Activated T cells in the rheumatoid synovium express RANKL. Synoviocytes can differentiate to osteoclast-like cells under specific conditions, particularly when they are cultured with M-CSF and RANKL. Thus, the bony erosions seen in RA may result from RANKL/RANK system activation by activated T cells. This raises the possibility that OPG therapy to block this mechanism might prove beneficial in patients with RA.

Topics: Animals; Arthritis, Rheumatoid; Glycoproteins; Humans; Inflammation; Mice; Osteoblasts; Osteolysis; Osteoprotegerin; Rats; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Bone Resorption; Collagen Diseases; Cytokines; Diphosphonates; Glycoproteins; Humans; Inflammation Mediators; Interleukin 1 Receptor Antagonist Protein; Osteoprotegerin; Prednisolone; Receptors, Cytoplasmic and Nuclear; Receptors, Interleukin-1; Receptors, Interleukin-6; Receptors, Tumor Necrosis Factor; Recombinant Proteins; Sialoglycoproteins; Tumor Necrosis Factor-alpha

Topics: Animals; Arthritis, Rheumatoid; Bone Density; Bone Resorption; Disease Models, Animal; Glycoproteins; Humans; Osteoporosis; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Vaccines

Focal bone loss in inflammatory arthritis begins early in the disease process and can contribute to patient morbidity. Current treatment strategies primarily target suppression of the inflammatory cascade with varying success in limiting the progression of focal bone destruction. This review outlines the current understanding of the mechanisms mediating inflammation-induced focal bone loss in rheumatoid arthritis and other inflammatory arthritides and highlights recent studies in animal models of arthritis that have contributed to our knowledge of this process.. Bone-resorbing osteoclasts have been identified as important effector cells in inflammation-induced bone loss in both experimental animal models and human rheumatoid arthritis and psoriatic arthritis. The RANK/RANKL (receptor activator of nuclear factor-kappaB and RANK ligand) pathway has been shown to be essential for osteoclast differentiation in inflammatory arthritis. In addition, in vitro and in vivo studies have demonstrated that many cytokines and growth factors elaborated by inflamed synovial tissues may contribute to osteoclast differentiation and activation.. Elucidation of the mechanisms mediating osteoclast differentiation and function has identified new pathways for potential targeted therapeutic intervention for focal bone loss in inflammatory arthritis. Challenges in the application of this approach are that therapies targeting the osteoclast would need to be used in combination with effective anti-inflammatory agents, and that pathways mediating osteoclast differentiation and function would need to remain at least partially functional to allow for continued skeletal remodeling.

Topics: Arthritis, Rheumatoid; Bone Resorption; Glycoproteins; Humans; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Over the past decade there have been major advances in our understanding of the factors that regulate osteoclast formation and activity. It is now apparent that receptor activator NFkappaB (RANK), its ligand, RANKL (also known as TRANCE, osteoclast differentiation factor and osteoprotegerin (OPG) ligand) and the natural RANKL inhibitor, OPG, are the key factors regulating osteoclast formation in normal bone physiology. The molecular interactions of these molecules regulate osteoclast formation and subsequent bone loss in disease and there is now strong evidence that the bone loss associated with inflammatory diseases, such as rheumatoid arthritis, periodontal disease and peri-implant loosening, is regulated by the action of RANK, RANKL, and OPG. These molecules are targets for the pharmacological regulation of severe bone loss in several common inflammatory diseases.

Topics: Animals; Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Cell Differentiation; Glycoproteins; Humans; Ligands; Membrane Glycoproteins; NF-kappa B; Osteitis; Osteoclasts; Osteolysis; Osteoprotegerin; Periodontitis; Prosthesis Failure; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

The TNF-family molecule receptor activator of nuclear factor kappa B (NFkappaB) ligand (RANKL) (OPGL, TRANCE, ODF) and its receptor activator of NFkappaB (RANK) are key regulators of bone remodeling and regulate T cell/dendritic cell communications, and lymph node formation. Moreover, RANKL and RANK are expressed in mammary gland epithelial cells and control the development of a lactating mammary gland during pregnancy. Genetically, RANKL and RANK are essential for the development and activation of osteoclasts and bone loss in response to virtually all triggers tested. Inhibition of RANKL function via the natural decoy receptor osteoprotegerin (OPG, TNFRSF11B) prevents bone loss in postmenopausal osteoporosis and cancer metastases. Importantly, RANKL appears to be the pathogenetic principle that causes bone and cartilage destruction in arthritis, and OPG treatment prevents bone loss at inflamed joints and has partially beneficial effects on cartilage destruction in all arthritis models studied so far. Modulation of these systems provides a unique opportunity to design novel therapeutics to inhibit bone loss and crippling in arthritis.

Topics: Animals; Antirheumatic Agents; Arthritis, Rheumatoid; Bone Remodeling; Carrier Proteins; Cell Differentiation; Dendritic Cells; Female; Glycoproteins; Humans; Ligands; Male; Osteoclasts; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Risk Factors; Sensitivity and Specificity

Topics: Animals; Arthritis, Rheumatoid; Bone Remodeling; Bone Resorption; Cell Differentiation; Cytokines; DNA-Binding Proteins; Glycoproteins; Humans; Interferon-beta; Interferon-Stimulated Gene Factor 3; Interferon-Stimulated Gene Factor 3, gamma Subunit; NFATC Transcription Factors; Nuclear Proteins; Osteoclasts; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction; STAT1 Transcription Factor; Synovial Membrane; T-Lymphocytes; Trans-Activators; Transcription Factors; Transcription, Genetic

Topics: Animals; Arthritis, Rheumatoid; Bone Demineralization, Pathologic; Bone Diseases; Bone Remodeling; Bone Resorption; Carrier Proteins; Glycoproteins; Humans; Membrane Glycoproteins; Mice; NF-kappa B; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Vaccines

Rheumatoid arthritis (RA) is characterised by the presence of an inflammatory synovitis accompanied by destruction of joint cartilage and bone. Destruction of cartilage matrix results predominantly from the action of connective tissue proteinases released by RA synovial tissues, chondrocytes, and pannus tissue. Several lines of evidence in RA and in animal models of arthritis support a role for osteoclasts in the pathogenesis of bone erosions. RA synovial tissues produce a variety of cytokines and growth factors that may increase osteoclast formation, activity, and/or survival. These include interleukin 1alpha (IL1alpha) and beta, tumour necrosis factor alpha (TNFalpha), IL11, IL17, and macrophage colony stimulating factor (M-CSF). Receptor activator of NFkappaB ligand (RANKL) is an essential factor for osteoclast differentiation and also functions to augment T cell-dendritic cell cooperative interactions. CD4+ T cells and synovial fibroblasts derived from RA synovium are sources of RANKL. Furthermore, in collagen induced arthritis (CIA), blockade with osteoprotegerin (OPG), a decoy receptor for RANKL, results in protection from bone destruction. To further evaluate the role of osteoclasts in focal bone erosion in arthritis, arthritis was generated in the RANKL knockout mouse using a serum transfer model. Despite ongoing inflammation, the degree of bone erosion in arthritic RANKL knockout mice, as assessed by microcomputed tomography and correlated histopathological analysis, was dramatically reduced compared with that seen in arthritic control mice. Cartilage damage was present in both the arthritic RANKL knockout mice and in arthritic control littermates, with a trend toward milder cartilage damage in the RANKL knockout mice. This study supports the hypothesis that osteoclasts play an important part in the pathogenesis of focal bone erosion in arthritis, and reveals distinct mechanisms of cartilage destruction and bone erosion in this animal model of arthritis. Future directions for research in this area include the further investigation of a possible direct role for the RANKL/RANK/OPG system in cartilage metabolism, and the possible role of other cell types and cytokines in bone erosion in arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Carrier Proteins; Glycoproteins; Humans; Membrane Glycoproteins; Mice; Mice, Knockout; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Animals; Arthritis, Rheumatoid; Bone and Bones; Cytoprotection; Glycoproteins; Humans; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction

Bone destruction in rheumatoid arthritis is characterized as 'the defective control of bone metabolism by the immune system'. During the course of our study to investigate the mechanism of arthritic bone destruction, we have explored a new field called' osteo-immunology'. Here we summarize the regulation of the bone metabolism by signalling cross-talk between RANKL and IFNs, focusing on the T cell-mediated regulation of osteoclastogenesis by IFN-gamma. The better understanding of the interactions between bone and immune cells will provide further insights into the both fields.

Topics: Arthritis, Rheumatoid; Bone and Bones; Bone Resorption; Cytokines; Glycoproteins; Humans; Immunity; Osteoclasts; Osteoprotegerin; Receptors, Antigen, T-Cell; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Signal Transduction

Bone loss represents a major unsolved problem in rheumatoid arthritis (RA). The skeletal complications of RA consist of focal bone erosions and periarticular osteoporosis at sites of active inflammation, and generalized bone loss with reduced bone mass. New evidence indicates that osteoclasts are key mediators of all forms of bone loss in RA. TNF-alpha is one of the most potent osteoclastogenic cytokines produced in inflammation and is pivotal in the pathogenesis of RA. Production of tumor necrosis factor-alpha (TNF-alpha) and other proinflammatory cytokines in RA is largely CD4(+) T-cell dependent and mostly a result of interferon-gamma (IFN-gamma) secretion. Synovial T cells contribute to synovitis by secreting IFN-gamma and interleukin (IL)-17 as well as directly interacting with macrophages and fibroblasts through cell-to-cell contact mechanisms. Activated synovial T cells express both membrane-bound and soluble forms of receptor activator of NF-kappaB ligand (RANKL). In rheumatoid synovium, fibroblasts also provide an abundant source of RANKL. Furthermore, TNF-alpha and IL-1 target stromal-osteoblastic cells to increase IL-6, IL-11, and parathyroid hormone-related protein (PTHrP) production as well as expression of RANKL. In the presence of permissive levels of RANKL, TNF-alpha acts directly to stimulate osteoclast differentiation of macrophages and myeloid progenitor cells. In addition, TNF-alpha induces IL-1 release by synovial fibroblasts and macrophages, and IL-1, together with RANKL, is a major survival and activation signal for nascent osteoclasts. Consequently, TNF-alpha and IL-1, acting in concert with RANKL, can powerfully promote osteoclast recruitment, activation, and osteolysis in RA. The most convincing support for this hypothesis has come from in vivo studies of animal models. Protection of bone in the presence of continued inflammation in arthritic rats treated with osteoprotegerin (OPG) supports the concept that osteoclasts mediate bone loss, providing further evidence that OPG protects bone integrity by downregulating osteoclastogenesis and promoting osteoclast apoptosis. Modulation of the RANKL/OPG equilibrium in arthritis may provide additional skeletal benefits, such as chondroprotection. The nexus between T-cell activation, TNF-alpha overproduction, and the RANKL/OPG/RANK ligand-receptor system points to a unifying paradigm for the entire spectrum of skeletal pathology in RA. Strategies that address osteoclastic bone resorption w

Topics: Arthritis, Rheumatoid; Glycoproteins; Humans; Osteoclasts; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tumor Necrosis Factor-alpha

Topics: Arthritis, Rheumatoid; Bone Density; Bone Resorption; Calcium, Dietary; Cholecalciferol; Cytokines; Glycoproteins; Humans; Methotrexate; Osteoclasts; Osteoporosis; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Synovial Membrane

Topics: Alveolar Bone Loss; Animals; Arthritis, Rheumatoid; Bone Resorption; Cell Differentiation; Glycoproteins; Humans; Lipoproteins; Macrophages; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Osteoclasts; Osteoprotegerin; p38 Mitogen-Activated Protein Kinases; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Animals; Arthritis, Rheumatoid; Glycoproteins; Humans; Ligands; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Animals; Arthritis, Rheumatoid; Bone Diseases, Metabolic; Bone Neoplasms; Carrier Proteins; Cytokines; Female; Glycoproteins; Humans; Hyperparathyroidism; Ligands; Male; Membrane Glycoproteins; Mice; Mice, Knockout; Mice, Transgenic; Middle Aged; Osteitis Deformans; Osteoclasts; Osteoporosis; Osteoporosis, Postmenopausal; Osteoprotegerin; RANK Ligand; Rats; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tumor Necrosis Factor-alpha

Topics: Animals; Arthritis, Rheumatoid; Carrier Proteins; Glycoproteins; Humans; Membrane Glycoproteins; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

To explore the mechanism of. The B cell subgroups in RA patients were correlated with the RANKL/RANK/OPG system. Treatment with

Topics: Arthritis, Rheumatoid; Drugs, Chinese Herbal; Humans; Methotrexate; Osteoclasts; Osteoprotegerin; RANK Ligand; Tartrate-Resistant Acid Phosphatase

Periodontal disease (PD) and rheumatoid arthritis (RA) are bone pathologies mediated through immuno-inflammatory mechanisms. The aim of this study was to investigate the serum markers osteopontin (OPN), tumor necrosis factor receptors 1 (TNFR1) and 2 (TNFR2) receptor activator of nuclear factor-kappa B ligand (RANKL) and RANKL/ osteoprotegerin (OPG) ratio and compare them in PD and RA groups.. RA (with PD = 19 and without PD = 19), PD (n = 38) and 14 healthy subjects underwent bleeding on probing (BOP) and probing pocket depth (PPD) measurement. PD was defined as PPD measuring ≥5mm registered in ≥3 sites. Marginal bone loss (MBL) for premolars and molars was measured on digital panoramic radiographs. Serum samples were collected from all subjects. OPN, TNFR1, TNFR2 and RANKL were measured by enzyme-linked immunosorbent assays (ELISAs). OPG was measured as part of a multiplex proximity extension assay (PEA).. OPN, TNFR1, TNFR2 and RANKL serum levels were the highest in the RA group with PD, while the RA group without PD were comparable to PD subjects only. The RANKL/OPG ratios were comparable between PD group and both RA groups with (p = 0.051) and without PD (p = 0.37). Serum RANKL levels were associated with MBL (p = 0.008) and PPD ≥ 5mm (p = 0.01).. Peripheral osteoclastogenesis is a feature of periodontal disease with systemic levels of osteoclastogenic markers comparable to the effects observed in rheumatoid arthritis.

Topics: Adult; Arthritis, Rheumatoid; Biomarkers; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Osteoprotegerin; Periodontal Diseases; RANK Ligand; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II

The present study aimed to evaluate proinflammatory cytokine and vitamin D levels in rheumatoid arthritis (RA) and chronic periodontitis (CP) patients and healthy individuals before and after initial periodontal treatment. Overall, 17 CP patients with RA (RA + CP), 18 systemically healthy CP patients (CP), and 18 healthy controls (C) were included. Clinical periodontal measurements were recorded and gingival crevicular fluid (GCF) and blood samples were recorded. RA + CP and CP patients received nonsurgical periodontal treatment. Vitamin D, tumor necrosis factor (TNF)-α, receptor activator of nuclear factor-KB ligand (RANKL), and OPG levels were determined in GCF and serum. Baseline clinical parameters were similar in all periodontitis groups (P > 0.05) but were higher than that in controls (P < 0.05). Periodontal treatment improved clinical parameters in all periodontitis groups (P < 0.05). GCF vitamin D levels were higher in RA + CP and CP groups than in healthy controls, but these levels decreased in the RA + CP group after periodontal treatment (P < 0.05). Serum RANKL and GCF TNF-α levels in RA patients decreased after periodontal treatment (P < 0.05). Within the limitations of this study, the results suggested that GCF vitamin D levels are increased in RA patients and decrease after periodontal treatment; therefore, local vitamin D levels might be an important indicator of periodontal bone loss.

Topics: Adult; Arthritis, Rheumatoid; Case-Control Studies; Female; Gingival Crevicular Fluid; Humans; Male; Middle Aged; Osteoprotegerin; Periodontitis; RANK Ligand; Tumor Necrosis Factor-alpha; Vitamin D

Objective To observe the efficacy of Hebi Formula (HF) combined Methotrexate (MTX) on early rheumatoid arthritis (RA) patients with disharmony of Gan and Pi syndrome (DGPS) and its effects on matrix metalloproteinase-3 (MMP-3) activator of nuclear factor-KB/receptor activator of nu- clear factor-KB/osteoprotegerin (RANK/RANKL/OPG). Methods Totally 72 early RA patients with DGPS were assigned to the treatment group and the control group according to random digit table, 36 in each group. Patients in the control group took MTX, while those in the treatment group additionally took HF. MTX dose was increased from 7. 5 mg to 12. 5 mg gradually, once per week, and the course of treatment was 24 weeks. Efficacy for Chinese medicine (CM) syndromes, ACR20 improvement rate, laboratory re- lated indices [ rheumatoid factor ( RF ) , erythrocyte sedimentation rate ( ESR ) , C-reactive protein (CRP) , anti-cyclic citrullinated peptide antibody (CCP)], serum levels of MMP-3, OPG, RANKL, and adverse reactions were observed. Results The standard arriving rate of ACR20 was 82. 86% (2935) in the treatment group, higher than that in the control group [51. 52% (173) ;P <0. 05). The effective rate of CM syndrome was 85. 7% (30f35) in the treatment group, higher than that in the control group [63. 6% (21/33) ;P <0. 05). Compared with before treatment in the same group, levels of RF,ESR,CRP,MMP-3, and RANKL decreased, the OPG level increased in the two groups after treatment (P <0. 05, P <0. 01). Compared with the control group, levels of RF, ESR, CRP, and RANKL all decreased with statistical difference (P <0. 01 , P <0. 05). Liver dysfunction occurred in 1 case of the treatment group. Leucopenia occurred in 1 case and liver dysfunction occurred in 2 cases of the control group. Conclusion HF com- bined MTX could improve symptoms of early RA patients with DGPS, and regulate bone destruction in- duced by RANK/RANKL/OPG systems.

Topics: Antirheumatic Agents; Arthritis, Rheumatoid; Blood Sedimentation; Drugs, Chinese Herbal; Humans; Matrix Metalloproteinase 3; Methotrexate; Osteoprotegerin; RANK Ligand; Rheumatoid Factor; Syndrome

Osteoprotegerin (OPG) is considered an important biomarker in cardiovascular (CV) disease. CV disease is the most common cause of mortality in patients with rheumatoid arthritis (RA), a consequence of accelerated atherosclerosis. The present study aimed to evaluate the relationship of serum OPG levels to arterial stiffness, carotid intima-media thickness (CIMT), and clinical and laboratory indices in RA patients.. Included in the study were 68 RA patients with no history or signs of CV disease and 48 healthy subjects Disease activity was assessed by the 28-joint disease activity score (DAS28) in RA patients. Serum OPG level was measured using enzyme-linked immunosorbent assay (ELISA). Carotid femoral pulse wave velocity (PWV) was measured as an index of arterial stiffness and CIMT was evaluated by carotid ultrasonography.. The mean serum OPG level was significantly higher in RA patients than controls (p < 0.001). Mean PWV and CIMT were also significantly increased in RA patients compared to controls (both p < 0.001). In RA patients, serum OPG level was significantly correlated with PWV and CIMT, as well as rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody; but not with DAS28, high-sensitivity C-reactive protein (hsCRP), or erythrocyte sedimentation rate.. Serum OPG levels were increased and correlated with CIMT and PWV in RA patients. In addition to PWV and CIMT, OPG may be a useful biomarker for CV risk management in RA patients.

Topics: Arthritis, Rheumatoid; Carotid Artery Diseases; Carotid Intima-Media Thickness; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Osteoprotegerin; Pulse Wave Analysis; Reproducibility of Results; Sensitivity and Specificity; Statistics as Topic; Vascular Stiffness

Osteoprotegerin (OPG), a member of the tumor necrosis factor receptor family, has been identified as a critical regulator of bone resorption. Considering the possible role of OPG in rheumatoid arthritis (RA) and in the osteoclastogenesis suppression effects of statins, the present study aims to investigate the effects of fluvastatin on serum levels OPG and disease activity score (DAS) in patients with RA. Forty patients with RA were randomized in a placebo-controlled trial to receive 40 mg fluvastatin or placebo as an adjunct to existing disease-modifying antirheumatic drug (DMARD) therapy (methotrexate, leflunomide, hydroxychloroquine). Patients were followed up over 12 weeks. OPG and disease activity variables were measured at baseline and after 12 weeks of treatment. After 12 weeks, the OPG level was significantly increased in the fluvastatin group compared to the placebo group. DAS-28 was significantly decreased in the fluvastatin group compared to the placebo group. C-reactive protein (CRP), morning stiffness, swollen joint count (SJC), and tender joint count (TJC) were significantly decreased in the fluvastatin group compared to the placebo group; however, erythrocyte sedimentation rate (ESR), modified health assessment questionnaire (MHAQ), and visual analogue screen (VAS) were not changed significantly. In conclusion, fluvastatin administration could increase the OPG levels and improve disease activity variables in patients with RA. Therefore, fluvastatin may serve a potential benefit in the treatment of RA patients.

Topics: Adult; Antirheumatic Agents; Arthritis, Rheumatoid; C-Reactive Protein; Double-Blind Method; Drug Therapy, Combination; Fatty Acids, Monounsaturated; Female; Fluvastatin; Health Status; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Indoles; Male; Middle Aged; Osteoprotegerin; Pain Measurement; Treatment Outcome

To analyze the association between circulating osteoprotegerin (OPG) and Dickkopf-related protein 1 (DKK-1) and radiological progression in patients with tightly controlled rheumatoid arthritis (RA).. Serum levels of OPG and DKK-1 were measured in 97 RA patients who were treated according to a treat-to-target strategy (T2T) aimed at remission (DAS28<2.6). Radiologic joint damage progression was assessed by changes in the total Sharp-van der Heijde score (SHS) on serial radiographs of the hands and feet. The independent association between these biomarker levels and the structural damage endpoint was examined using regression analysis.. The mean age of the 97 RA patients (68 women) at the time of the study was 54 ± 14 years, and the median disease duration was 1.6 ± 1.5 years. Most patients were seropositive for either RF or ACPA, and the large majority (76%) were in remission or had low disease activity. After a median follow-up time of 3.3 ± 1.5 years (range, 1-7.5 yrs.), the mean total SHS annual progression was 0.88 ± 2.20 units. Fifty-two percent of the patients had no progression (defined as a total SHS of zero). The mean serum OPG level did not change significantly over the study period (from 3.9 ± 1.8 to 4.07 ± 2.23 pmol/L), whereas the mean serum DKK-1 level decreased, although not significantly (from 29.9 ± 10.9 to 23.6 ± 18.8 pmol/L). In the multivariate analysis, the predictive factors increasing the likelihood of total SHS progression were age (OR per year = 1.10; p = 0.003) and a high mean C-reactive protein level over the study period (OR = 1.29; p = 0.005). Circulating OPG showed a protective effect reducing the likelihood of joint space narrowing by 60% (95% CI: 0.38-0.94) and the total SHS progression by 48% (95% CI: 0.28-0.83). The DKK-1 levels were not associated with radiological progression.. In patients with tightly controlled RA, serum OPG was inversely associated with progression of joint destruction. This biomarker may be useful in combination with other risk factors to improve prediction in patients in clinical remission or low disease activity state.

Topics: Adult; Aged; Arthritis, Rheumatoid; Biomarkers; Female; Follow-Up Studies; Humans; Intercellular Signaling Peptides and Proteins; Joints; Longitudinal Studies; Male; Middle Aged; Osteoprotegerin; Prospective Studies

We aimed to investigate the expression and therapeutic modulation of the receptor activator of the NF-κB ligand (RANKL) system in early-untreated rheumatoid arthritis (RA).. In this study, 15 patients with newly diagnosed RA (median symptom duration 7 months) were started on methotrexate (MTX) 20 mg weekly. Synovial biopsies were obtained by needle arthroscopy at baseline and 8 weeks after initiation of therapy. X-rays of the hands and feet were obtained at baseline and 1 year after diagnosis. Immunohistochemistry was performed to detect RANKL, receptor activator of nuclear factor-κB (RANK) and osteoprotegerin (OPG) in the synovial biopsies. The in vitro effect of MTX was tested on RA-derived primary fibroblasts and the osteoblasts-like osteosarcoma cell line (rtPCR, Western blot and ELISA) and in osteoclasts (tartrate-resistant acid phosphatase staining and dentine pit formation assay).. MTX decreased synovial cellularity as well as RANK expression and the RANKL/OPG ratio. We confirmed this effect by a decrease of the mRNA and protein RANKL/OPG ratio in synovial-derived fibroblasts and osteoblasts-like tumoral cells exposed in vitro to methotrexate. Supernatants from MTX treated osteoblasts-like tumoral cells prevented pre-osteoclast formation in the absence of exogenous RANKL. Furthermore, MTX blocked osteoclastogenesis from peripheral blood mononuclear cells despite the presence of macrophage colony stimulating factor and RANKL, which indicates that MTX directly inhibits osteoclastogenesis.. The synovial membrane of early-untreated RA is characterized by a high RANKL/OPG ratio that can be reversed by methotrexate.

Topics: Adult; Aged; Arthritis, Rheumatoid; Blotting, Western; Bone Resorption; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunohistochemistry; Immunosuppressive Agents; Male; Methotrexate; Middle Aged; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Reverse Transcriptase Polymerase Chain Reaction; Synovial Membrane

To study the effects of low-dose prednisolone on the osteoclast-regulating proteins osteoprotegerin (OPG) and RANK ligand (RANKL) and on markers of bone resorption, 1CTP generated by MMPs and CTX-1 generated by cathepsin K, in patients with early RA in relation to inflammation and joint destruction.. In 225 patients, who at the start of the first DMARD had been randomized to 7.5 mg prednisolone daily for 2 years, the P-group, or no prednisolone, the NoP-group, OPG and RANKL were analysed at 0-24 months and 1CTP and CTX-1 at 0-12 months. Radiographs of hands and feet were assessed at 0, 1 and 2 years using the modified Sharp-van der Heijde score and radiological progression defined as increase in total Sharp score above 5.8. Data were analysed with a mixed linear model and by the GENMOD procedure.. In the P-group, RANKL and the ratio OPG/RANKL were stable between baseline and 24 months, whereas in the NoP-group, RANKL increased and the ratio OPG/RANKL decreased. CTX-1 decreased significantly more in the P-group. 1CTP decreased over time in both groups, but more in the P-group, P < 0.001, a difference also present in the subgroups of patients in remission. The decrease in 1CTP was associated with less radiological progression after 2 years and displayed a significant interaction with treatment.. Low-dose prednisolone may inhibit progression of joint destruction by interfering with MMP activity, seen as a marked decrease in 1CTP, as well as by impairing osteoclast activation, shown by a stable OPG/RANKL ratio.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid; Bone Resorption; Collagen Type I; Disease Progression; Female; Follow-Up Studies; Glucocorticoids; Humans; Male; Matrix Metalloproteinases; Middle Aged; Osteoclasts; Osteoprotegerin; Peptides; Prednisolone; Prospective Studies; Radiography; RANK Ligand; Remission Induction; Young Adult

To examine how rituximab may result in the inhibition of joint destruction in rheumatoid arthritis (RA) patients.. Twenty-eight patients with active RA were treated with rituximab. Radiographs of hands and feet before and 1 year after therapy were assessed using the Sharp-van der Heijde score (SHS). Expression of bone destruction markers was evaluated by immunohistochemistry and immunofluorescence of synovial biopsies obtained before and 16 weeks after the initiation of treatment. Serum levels of osteoprotegerin, receptor activator of nuclear factor κB ligand (RANKL), osteocalcin and cross-linked N-telopeptides of type I collagen (NTx) were measured by ELISA before and 16 weeks post-treatment.. After 1 year, the mean (SD) change in total SHS was 1.4 (10.0). Sixteen weeks after treatment there was a decrease of 99% in receptor activator of nuclear factor κB-positive osteoclast precursors (p=0.02) and a decrease of 37% (p=0.016) in RANKL expression in the synovium and a trend towards reduced synovial osteoprotegerin expression (25%, p=0.07). In serum, both osteoprotegerin (20%, p=0.001) and RANKL (40%, p<0.0001) levels were significantly reduced 16 weeks after treatment, but the osteoprotegerin/RANKL ratio increased (157%, p=0.006). A trend was found towards an increase of osteocalcin levels (p=0.053), while NTx concentrations did not change.. Rituximab treatment is associated with a decrease in synovial osteoclast precursors and RANKL expression and an increase in the osteoprotegerin/RANKL ratio in serum. These observations may partly explain the protective effect of rituximab on the progression of joint destruction in RA.

Topics: Adult; Aged; Antibodies, Monoclonal, Murine-Derived; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Bone Resorption; Disease Progression; Female; Follow-Up Studies; Foot Joints; Hand Joints; Humans; Male; Middle Aged; Osteocalcin; Osteoclasts; Osteogenesis; Osteoprotegerin; Radiography; RANK Ligand; Rituximab; Synovial Membrane; Young Adult

To explore the potential role of Dickkopf-1 (DKK-1) in rheumatoid arthritis (RA) and to evaluate the effect of a tumor necrosis factor-α (TNF-α) inhibitor (infliximab) and an interleukin 1 receptor antagonist (IL-1Ra; anakinra) on DKK-1 secretion in patients with RA.. Serum samples were collected from 100 patients with RA, 100 patients with other rheumatic diseases (e.g., osteoarthritis and ankylosing spondylitis), and 40 healthy controls. DKK-1 and osteoprotegerin (OPG) levels in serum were detected by ELISA. Serum C-reactive protein (CRP) levels, erythrocyte sedimentation rates (ESR), rheumatoid factor (RF) titers, and anti-cyclic citrullinated peptide antibody were also measured in patients with RA.. The serum level of DKK-1 was significantly higher in patients with RA than in healthy controls and those with other rheumatic diseases (p < 0.01); the serum DKK-1 level was correlated with levels of CRP (r = 0.488, p = 0.003) and ESR (r = 0.458, p = 2.4 x 10(-4)) and the Sharp score of radiologic change (r = 0.449, p = 0.001) in RA. In contrast to the increasing level of OPG, DKK-1 was significantly decreased in RA patients treated with TNF-α inhibitor (p < 0.01). DKK-1 was significantly decreased in RA patients treated with IL-1Ra (p < 0.01).. DKK-1, as an important mediator, was correlated with bone erosion and inflammation in RA. The change of DKK-1 level may serve as a biomarker of disease activity and bone erosion.

Topics: Adult; Aged; Arthritis, Rheumatoid; Bone Resorption; C-Reactive Protein; Enzyme-Linked Immunosorbent Assay; Female; Humans; Inflammation; Intercellular Signaling Peptides and Proteins; Interleukin 1 Receptor Antagonist Protein; Male; Middle Aged; Osteoprotegerin; Tumor Necrosis Factor-alpha; Young Adult

The objective of the study was to evaluate synovial tissue receptor activator of nuclear factor-κβ ligand (RANKL) and osteoprotegerin (OPG) as biomarkers of disease activity, progressive joint damage, and therapeutic response, during cytokine blockade in rheumatoid arthritis (RA). Patients with active RA entered a randomized open-label 12-month study of anakinra 100 mg/day, administered as monotherapy or in combination with pegsunercept 800 μg/kg twice weekly. Arthroscopic synovial tissue biopsies were obtained at baseline, at 4 weeks and at the final time point. Following immunohistochemical staining, RANKL and OPG expression was quantified using digital image analysis. Radiographic damage was evaluated using the van der Heijde modification of the Sharp scoring system. Twenty-two patients were randomized. Baseline expression of RANKL, but not OPG, correlated significantly with baseline CRP levels (r = 0.61, P < 0.01). While a significant reduction in OPG expression following treatment was observed in clinical responders at the final time point (P < 0.05 vs. baseline), RANKL levels did not change, and the RANKL:OPG ratio remained unaltered, even at the highest levels of clinical response. When potential predictors of radiographic outcome were evaluated, baseline RANKL expression correlated with erosive progression at 1 year (r = 0.71, P < 0.01). Distinct, though related, pathophysiologic processes mediate joint inflammation and destruction in RA. Elevated synovial tissue RANKL expression is associated with progressive joint erosion, and may be independent of the clinical response to targeted therapy. The potential therapeutic importance of modulating RANKL in RA is highlighted, if radiographic arrest is to be achieved.

Topics: Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Biopsy; Disease Progression; Drug Therapy, Combination; Female; Health Status; Humans; Image Processing, Computer-Assisted; Interleukin 1 Receptor Antagonist Protein; Knee Joint; Male; Middle Aged; Osteoprotegerin; Radiography; RANK Ligand; Severity of Illness Index; Synovial Membrane

Soluble receptor activator of nuclear factor-kappa B ligand (sRANKL) to osteoprotegerin ratio is designated as a bone metabolism equation in many rheumatologic disorders and would be modified with fish oil (FO) supplementation.. Eighty-three females with rheumatoid arthritis were divided randomly to 40 and 43 patients treated with (1 g/day) or without FO for 3 months accompanied with conventional drugs, respectively. Osteoprotegerin, sRANKL, tumor necrosis factor alpha (TNFalpha) serum levels were measured before and after treatment.. Serum levels of osteoprotegerin increased, although sRANKL, TNFalpha and sRANKL/osteoprotegerin ratio decreased with FO therapy. A significant positive correlation was observed between sRANKL/osteoprotegerin ratio and TNFalpha levels (r=0.327, p=0.040) in the FO-treated group.. FO could decrease the inflammatory response by lowering of serum TNFalpha levels and sRANKL/osteoprotegerin ratio.

Topics: Adolescent; Adult; Aged; Arthritis, Rheumatoid; Bone and Bones; Dietary Supplements; Double-Blind Method; Down-Regulation; Female; Fish Oils; Humans; Middle Aged; Osteoprotegerin; Placebos; RANK Ligand; Solubility; Young Adult

To determine to what extent baseline measurements of the ratio receptor activator of nuclear factor-kappaB ligand (RANKL):osteoprotegerin (OPG) and C-terminal cross linking of type-I and type-II (CTX-I and CTX-II), in addition to traditional markers of disease severity, could predict annual radiological progression.. A cohort of 155 patients with early, active, untreated rheumatoid arthritis (RA) who participated in the Combination Therapy in Early Rheumatoid Arthritis trial (COBRA trial) was followed up for 11 years. Urine was sampled at baseline and after 3 months from the start of treatment and analysed for CTX-I and CTX-II. Baseline serum samples were analysed for RANKL and OPG. Available traditional markers of disease severity included baseline measurements of erythrocyte sedimentation rate, rheumatoid factor and baseline radiological damage. A digital database of frequent radiographs was available, scored according to the Sharp/van der Heijde method. Individual annual progression rates were calculated and used as outcome variable. Multiple linear regression analyses identified the strongest predictors of annual radiological progression.. In multivariable analyses the RANKL:OPG ratio and CTX-I or CTX-II proved to be independent predictors of annual radiological damage over 11 years. The prediction of annual radiological progression was strongest when the RANKL:OPG ratio and CTX-I or CTX-II were evaluated in the same model (36-39% explained variance). Adding the effect of treatment at 3 months to the baseline models improved the predictive ability of the models up to 44-46%.. Unfavourable baseline levels of the RANKL:OPG ratio as well as CTX-I and CTX-II in patients with early, active, untreated RA are strong independent predictors of rapid and persistent damage progression over the 11-year follow-up. Early improvement in bone markers by treatment predicts a better outcome.

Topics: Adult; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Bone Resorption; Cartilage Diseases; Collagen Type I; Collagen Type II; Disease Progression; Double-Blind Method; Drug Therapy, Combination; Female; Follow-Up Studies; Humans; Male; Middle Aged; Osteoprotegerin; Peptide Fragments; Peptides; Procollagen; Prognosis; RANK Ligand

To investigate histological evidence of bone remodeling in response to infliximab for rheumatoid arthritis (RA), bone marrow tissues were extracted from ten RA patients at the time of total knee arthroplasty after treatment of infliximab for an average of 16 months (range, 8-24 months). The patients had a mean age of 65.3 years (range, 57-76 years) with 4.8 mg/week of methotrexate (MTX; 4-6 mg) and 3.8 mg/day of prednisolone (2-5 mg). Control samples were obtained from ten RA patients who did not undergo infliximab therapy. These patients had an average age of 67.6 years (range, 59-78 years) and received 5.2 mg/week of MTX (4-6 mg) and 4.0 mg/day of prednisolone (2-5 mg). Histological examination of structural differences between the infliximab and control groups in bone marrow was performed using hematoxylin and eosin (H & E) to evaluate differences. In immunohistochemical examination, the expressions of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), receptor activator of nuclear (kappa) B ligand (RANKL), osteoprotegerin (OPG), and osteopontin (OPN) were compared between both groups. H & E staining revealed that the bone marrow tissues of the RA patients who underwent infliximab therapy demonstrated newly formed thickness of interstitial septum among the trabeculae as compared with the control group. Moreover, immunohistochemical examinations revealed that TNF-alpha, IL-6, RANKL, OPG, and OPN were expressed in this newly formed bone after infliximab therapy. Therefore, treatment with infliximab improved the histological changes with respect to bone metabolism in the newly formed bone marrow tissues.

Topics: Aged; Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Bone Marrow; Dose-Response Relationship, Drug; Female; Humans; Infliximab; Interleukin-6; Male; Middle Aged; Osteogenesis; Osteopontin; Osteoprotegerin; RANK Ligand; Tumor Necrosis Factor-alpha

To investigate the effects of vitamin K2 (Vit K2) alone or in combination with etidronate and risedronate on bone loss, osteoclast induction, and inflammation in patients with rheumatoid arthritis (RA).. Subjects comprised 79 patients with RA who were receiving prednisolone, divided into 3 groups: Group K, Vit K2 alone; Group KE, Vit K2 plus etidronate; and Group KR, Vit K2 plus risedronate. During a 24-month treatment and followup period, levels of N-terminal telopeptide of type I collagen (NTx) and bone alkaline phosphatase were measured. Bone mineral density (BMD) of the 3 groups was measured using dual-energy x-ray absorptiometry. Damage score to fingers on radiographic findings were measured according to the Larsen method. Serum levels of receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) were measured.. Falls in rate of change of BMD decreased after 18 months in groups KR and KE. Larsen damage scores indicated a significant difference between Group KE and other groups. Significant decreases in serum NTx were observed in groups KE and KR at all timepoints, but not in Group K. Levels of RANKL decreased significantly in all 3 groups.. Vit K2 alone or in combination with bisphosphonates for treatment of osteoporosis in patients with RA may inhibit osteoclast induction via decreases in levels of RANKL.

Topics: Aged; Alkaline Phosphatase; Arthritis, Rheumatoid; Bone Density; Bone Density Conservation Agents; Cohort Studies; Collagen Type I; Drug Therapy, Combination; Etidronic Acid; Female; Humans; Male; Middle Aged; Osteoclasts; Osteoporosis; Osteoprotegerin; Peptides; Prednisolone; Prospective Studies; RANK Ligand; Risedronic Acid; Vitamin K 2

To examine whether treatment with anti-tumour necrosis factor (TNF) alpha prevents loss of bone mineral density (BMD) at the spine and hip (generalised) and in the hands (local) of patients with rheumatoid arthritis, and to study the changes in markers of bone metabolism, including receptor activator of the NFkappaB ligand (RANKL) and osteoprotegerin (OPG), during anti-TNF treatment.. 102 patients with active rheumatoid arthritis, who were treated with infliximab during 1 year, were included in this open cohort study. The BMD of the spine and hip (dual x ray absorptiometry) and hands dual x ray radiogrammetry was measured before the start of treatment and after 1 year. Changes in osteocalcin formation, beta-isomerised carboxy terminal telopeptide of type 1 collagen (beta-CTx, resorption), RANKL and OPG were determined at 0, 14, 30 and 46 weeks.. The BMD of the spine and hip was unchanged during treatment with infliximab, whereas BMD of the hand decreased significantly by 0.8% (p<0.01). The BMD of the hip in patients with a good European League Against Rheumatism response showed a favourable change compared with patients not achieving such a response. Serum beta-CTx and RANKL were both considerably decreased compared with baseline at all time points. The decrease in beta-CTx was associated with the decrease in Disease Activity Score of 28 joints and C reactive protein during the 0-14 weeks interval.. In patients with rheumatoid arthritis treated with infliximab, spine and hip bone loss is arrested, whereas metacarpal cortical hand bone loss is not stopped. The outcome of the study also supports a relationship between clinical response, in terms of reduced inflammatory activity, and changes in bone loss of the spine, hip and hands.

Topics: Adult; Aged; Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Bone and Bones; Bone Density; Carrier Proteins; Female; Glycoproteins; Hand Bones; Hip Joint; Humans; Infliximab; Ligands; Male; Membrane Glycoproteins; Middle Aged; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Severity of Illness Index; Spine; Tumor Necrosis Factor-alpha

Rheumatoid arthritis (RA) is a chronic inflammatory disease that may result in debilitating joint deformities with destruction of bone and cartilage. Inflammation is still considered the pivotal inducer of both components of joint damage. Results of recent animal studies suggested a prominent contribution of osteoclastic bone resorption that could be dissociated from inflammation. RANKL and its natural decoy receptor, osteoprotegerin (OPG), play key roles in osteoclast activation. In a group of patients with early RA not treated with disease-modifying drugs, we tested the hypothesis that osteoclast activation, reflected by the serum OPG:RANKL ratio at baseline, is negatively associated with progression of bone damage, independent of inflammation.. OPG and RANKL levels, together with a parameter of inflammation (first-year time-averaged erythrocyte sedimentation rate [tESR]), were measured in 92 patients with newly diagnosed early active RA who were participants in a randomized study. The tESR and the OPG:RANKL ratio were evaluated for the ability to predict 5-year radiographic progression of joint damage.. The first-year tESR and the OPG:RANKL ratio, as measured at baseline, independently predicted 5-year radiographic progression of joint damage (both P < or = 0.001). Progression of radiographic damage was greatest in patients with a high tESR and a low OPG:RANKL ratio and was lowest in patients with a low tESR and a high OPG:RANKL ratio.. This study in patients with early untreated RA is the first to confirm the findings in animal models of arthritis, that radiographic progression of the bone component of joint destruction is dependent on both inflammation (tESR) and osteoclast activation (the OPG:RANKL ratio).

Topics: Arthritis, Rheumatoid; Arthrography; Blood Sedimentation; Carrier Proteins; Disease Progression; Female; Glycoproteins; Humans; Joints; Male; Membrane Glycoproteins; Middle Aged; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

To evaluate the role of serum osteoprotegerin (OPG) as a biochemical marker for disease activity assessment and drug monitoring in patients with rheumatoid arthritis (RA) treated with cyclical etidronate.. Forty patients (35 women and 5 men) with RA of <5 years duration were randomized to receive intermittent cyclical etidronate therapy in conjunction with anti-rheumatic therapy or anti-rheumatic therapy alone (without etidronate) in a 2-year, open-label protocol.. Radiographs of hands and feet and serum samples for the determination of OPG, amino terminal propeptide (PINP), cross-linked C-telopeptide (ICTP) and amino terminal telopeptid of type I collagen were obtained at baseline and at 24 months.. Etidronate treatment had no effect on circulating OPG levels, although the significant decline in PINP and ICTP (P=0.001 and P=0.04 respectively) reflected the efficacy of the anti-resorptive therapy. At baseline and at study termination, serum OPG correlated significantly with age (r=0.45; P=0.003 and r=0.56; P=0.0002 respectively). OPG was not related to biochemical markers of bone metabolism, indices of disease activity or radiographic disease progression. At baseline, the mean serum OPG was higher in patients receiving 5-10 mg/day prednisone (82.8+/-4.0 pg/ml, n=16) compared with those receiving <5 mg/day or with no prednisone (69.7+/-4.7 pg/ml, n=23) (P=0.05).. Our results suggested that serum OPG measurement, perhaps because of the complexity of the regulation of the OPG, may be difficult to utilize in the evaluation of anti-resorptive therapy. Moreover, low dose corticosteroid-associated osteoporosis is probably not mediated by inhibition of OPG.

Topics: Adult; Aged; Arthritis, Rheumatoid; Arthrography; Collagen Type I; Disease Progression; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Etidronic Acid; Female; Glycoproteins; Humans; Male; Middle Aged; Osteoprotegerin; Peptide Fragments; Peptides; Prednisone; Procollagen; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Hormone replacement therapy (HRT) modulates the imbalance in bone remodeling, thereby decreasing bone loss. Sex hormones are known to influence rheumatic diseases. The aim of this study was to investigate the effects of HRT on the serum levels of hormones and cytokines regulating bone turnover in 88 postmenopausal women with active rheumatoid arthritis (RA) randomly allocated to receive HRT plus calcium and vitamin D3 or calcium and vitamin D3 alone for 2 years. An increase in estradiol (E2) correlated strongly with improvement of bone mineral density in the hip (P < 0.001) and lumbar spine (P < 0.001). Both baseline levels and changes during the study of IL-6 and erythrocyte sedimentation rate were correlated positively (P < 0.001). HRT for 2 years resulted in an increase of the bone anabolic factor, insulin-like growth factor 1 (IGF-1) (P < 0.05) and a decrease of serum levels of soluble IL-6 receptor (sIL-6R) (P < 0.05), which is known to enhance the biological activity of IL-6, an osteoclast-stimulating and proinflammatory cytokine. Baseline levels of IL-6 and IGF-1 were inversely associated (P < 0.05), and elevation of IGF-1 was connected with decrease in erythrocyte sedimentation rate (P < 0.05) after 2 years. Interestingly, increase in serum levels of E2 was associated with reduction of sIL-6R (P < 0.05) and reduction of sIL-6R was correlated with improved bone mineral density in the lumbar spine (P < 0.05). The latter association was however not significant after adjusting for the effect of E2 (P = 0.075). The influences of IGF-1 and the IL-6/sIL-6R pathways suggest possible mechanisms whereby HRT may exert beneficial effects in RA. However, to confirm this hypothesis future and larger studies are needed.

Topics: Aged; Arthritis, Rheumatoid; Cytokines; Estrogen Replacement Therapy; Female; Follow-Up Studies; Glycoproteins; Humans; Insulin-Like Growth Factor I; Middle Aged; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Interleukin-6; Receptors, Tumor Necrosis Factor

In chronic arthropathies, there are several mechanisms of joint destruction. In recent years, studies have reported the implication of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in the process of activation and differentiation of osteoclasts, a key cell in the development of bone erosion. The RANKL/OPG ratio is increased in the serum of patients with malignant diseases and lytic bone disease, as well as rheumatoid arthritis (RA). The objective of this study was to measure and compare the concentrations of OPG and RANKL in the synovial fluid (SF) of patients with rheumatoid arthritis, spondyloarthritis (SpA) and osteoarthritis (OA).. This was an observational and cross-sectional study with 83 patients, 33 with RA, 32 with SpA and 18 with OA, followed up regularly in the outpatient clinics of the Rheumatology Department of the Clinics Hospital of the Ribeirão Preto Medical School-USP. All patients were assessed for indications for arthrocentesis by the attending physicians at the time of SF collection and were evaluated for demographic variables and medication use. Disease activity was assessed in individuals with RA and SpA. The quantification of SF OPG and RANKL levels was performed by ELISA, and the correlations of the results with clinical, laboratory and radiological parameters were assessed.. We found no statistically significant difference in the RANKL and OPG levels among the groups. Patients with RA showed a positive correlation between the SF cell count and RANKL level (r = 0.59; p < 0.05) and the RANKL/OPG ratio (r = 0.55; p < 0.05). Patients with OA showed a strong correlation between C-reactive protein (CRP) and the RANKL/OPG ratio (r = 0.82; p < 0.05). There was no correlation between the OPG and RANKL levels and markers of inflammatory activity or the disease activity index in patients with RA or SpA.. Within this patient cohort, the RANKL/OPG ratio was correlated with the SF cell count in patients with RA and with serum CRP in patients with OA, which may suggest a relationship with active inflammation and more destructive joint disease.

Topics: Arthritis, Rheumatoid; Cross-Sectional Studies; Humans; Ligands; NF-kappa B; Osteoarthritis; Osteoprotegerin; Spondylarthritis

Bone erosion in rheumatoid arthritis (RA) is partly caused by excessive activation of osteoclasts. Osteoclasts can be derived from RA synovium and their differentiation can be inhibited by osteoprotegerin (OPG), a decoy receptor of the osteoclastogenesis-promoting cytokine receptor activator of nuclear factor κB ligand (RANKL). Fibroblast-like synoviocytes (FLSs) are the main stromal cells in the synovium that can secret OPG. The OPG secretion of FLSs can be modulated by various cytokines. Interleukin (IL)-13 can alleviate bone erosion in RA mouse models, but the mechanisms remain unclear. Therefore, we aimed to investigate whether IL-13 can induce OPG secretion by RA-FLSs, thus ameliorating bone destruction in RA by inhibiting osteoclast differentiation.. OPG, RANKL, and IL-13 receptors expression by RA-FLSs were evaluated by RT-qPCR. OPG secretion was determined by ELISA. Western blot was performed to analyse OPG expression and the activation of the STAT6 pathway. IL-13 and (or) OPG siRNA pre-treated RA-FLSs conditioned medium were used in osteoclast induction to test if IL-13 can inhibit osteoclastogenesis by up-regulating OPG in RA-FLSs. Micro-CT and immunofluorescence were performed to determine if IL-13 can induce OPG expression and alleviate bone erosion in vivo.. IL-13 can promote OPG expression of RA-FLSs, and the promotion can be overcome by IL-13Rα1 or IL-13Rα2 siRNA transfection, or STAT6 inhibitor. Osteoclast differentiation can be inhibited by IL-13 pre-treated RA-FLSs conditioned medium. The inhibition can be reversed by OPG siRNA transfection. IL-13 injection can increase OPG expression in the joints while reducing bone destruction in collagen-induced arthritis mice.. IL-13 can inhibit osteoclastogenesis by up-regulating OPG in RA-FLSs through IL-13 receptors via the STAT6 pathway, thus may ameliorate bone erosion in RA.

Topics: Animals; Arthritis, Rheumatoid; Cells, Cultured; Culture Media, Conditioned; Cytokines; Fibroblasts; Interleukin-13; Mice; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptors, Interleukin-13; RNA, Small Interfering; Synoviocytes

Nigella glandulifera Freyn et Sint. (N. glandulifera) seeds are widely used in traditional Uyghur medicine for a variety of immuno-inflammatory diseases. The total saponins from N. glandulifera seeds (TSNGS) have been shown to have analgesic, antioxidant, and anti-inflammatory effects that can alleviate joint pain and swelling.. Rheumatoid arthritis (RA) is a chronic and progressive, debilitating autoimmune disease for which current treatments are not sufficiently effective and result in unsatisfactory side effects. This study aimed to mechanistically investigate the therapeutic effects of TSNGS on RA.. Qualitative analysis of TSNGS was performed using ultra-high-performance liquid chromatography-Q-Orbitrap-high-resolution mass spectrometry. Rats with collagen-induced arthritis (CIA), IL-1β-induced HFLS-RAs, and VEGF-induced HUVECs were analyzed to determine the efficacy and mechanism of TSNGS on RA.. It was established that TSNGS provides a therapeutic effect on RA by alleviating synovitis, bone degeneration, and angiogenesis via the OPG/RANKL/NF-κB and Ang/Tie-2 pathways and may be used for the treatment of RA.

Topics: Angiopoietins; Animals; Antirheumatic Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Dose-Response Relationship, Drug; Female; Male; NF-kappa B; Nigella; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Receptor, TIE-2; Saponins; Seeds

We aimed to explore whether the rs2073618 variant (G1181C) of the osteoprotegerin (OPG) gene and the methylenetetrahydrofolate reductase (MTHFR) rs1801131 (A1298AC) and rs1801133 (C677T) gene polymorphisms contribute to rheumatoid arthritis (RA) susceptibility and RA related subclinical atherosclerosis. Overall 283 RA patients and 595 healthy controls (HC) were genotyped for common variants of the OPG and MTHFR genes using PCR based assays. Clinical and laboratory parameters were recorded following thorough chart review. Surrogate markers of subclinical atherosclerosis (Carotid/Femoral intima media thickness/plaque formation) along with traditional risk factors for atherosclerosis were assessed in all RA patients and 280HC. Increased prevalence of the CC genotype of the rs2073618 variant was detected in RA patients vs HC (42.4% vs. 33%, p-value: 0.04). RA patients with high serum titers of rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP) antibodies displayed increased prevalence of the CC genotype of the rs2073618 variant of the OPG gene compared to HC (48.6% and 47.5 vs 33.3%, p-values: 0.0029and 0.0077 respectively). Of interest, this genotype turned to be associated with higher carotid IMT scores (0.872 ± 0.264 vs 0.816 ± 0.284, p-value: 0.01) and marginally with higher rates of carotid plaque formation (66% vs 54.1%, p = 0.06). The MTHFR 1298CC genotype was more prevalent only in the anti-CCP positive group compared to HC, with no associations detected with markers of subclinical atherosclerosis, following adjustment for traditional cardiovascular (CVD) risk factors. Reduced rates of carotid/femoral plaque formation were detected among RA patients harboring the MTHFR TT genotype (52.4 vs 72.7, p-value: 0.009, respectively). This association remained significant following adjustment for classical CVD risk factors (OR [95% CI 0.364 [0.173-0.765], p-value: 0.008). Genetic variations of the osteoprotegerin and MTHFR genes seem to increase susceptibility for seropositive RA and potentially contribute to subclinical atherosclerosis linked to RA. Larger studies are needed to confirm these findings.

Topics: Arthritis, Rheumatoid; Atherosclerosis; Biomarkers; Carotid Intima-Media Thickness; Disease Susceptibility; Humans; Methylenetetrahydrofolate Reductase (NADPH2); Osteoprotegerin; Risk Factors

Rheumatoid arthritis (RA) is a systemic autoimmune disease that often results in joint destruction. Ershiwuwei Lvxue Pill (ELP), a prescription of Tibetan medicine, has been used for centuries for the clinical treatment of RA in Tibet, China. In a previous study, we reported that ELP could ameliorate RA symptoms in CIA rats by inhibiting the inflammatory response and inducing apoptosis in synovial tissues. It is still needed further to clarify the mechanisms of action of ELP in mitigating RA.. In this study, we aim to elucidate the mechanism of action of ELP to improve RA joint damage and explore the changes in the intestinal flora and host metabolites.. Firstly, we analyzed the main absorbed constituents of ELP in the serum of rats by ultra-performance liquid chromatography quadrupole-time-flight mass spectrometry (UPLC-Q-TOF/MS). Then, we verified the alleviating effects of ELP on cartilage injury and bone erosion as well as the inflammatory response in CIA rats by microCT, H&E staining, safranin-O staining, and ELISA. Moreover, we investigated the main factors that mediate joint damage, including the production of matrix metalloproteinases (MMPs) and osteoclast activity in the ankle of rats by immunohistochemistry and tartrate-resistant acid phosphatase (TRAP) staining. Further, we explored the molecular mechanisms of the MMPs production and osteoclast activity in CIA rats treated with ELP through various experiments such as ELISA, qRT-PCR, western blotting, and immunofluorescence assay. Besides, we investigated gut microbiota composition by 16S rDNA sequencing and serum metabolites through untargeted metabolomics. In addition, we analyzed the correlation between gut microbiota and metabolites by Spearman correlation analysis.. In this study, we identified 20 compounds from rat serum samples, which could be the ELP components that improve RA. Moreover, we found that ELP could alleviate cartilage and bone injury by reducing MMP-1, MMP-3, and MMP-13 expression and osteoclast activity in CIA rats. Further studies demonstrated that ELP could reduce joint damage by inhibiting osteoprotegerin (OPG)/receptor activator for nuclear factor-κB ligand (RANKL) /nuclear factor-κB (NF-κB) and extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinases (JNK) signal pathways. The 16S rDNA sequencing analysis indicated that there was a significant difference in the gut microbiota composition between the normal and CIA rats, and these differences were changed after ELP administration. ELP could alter the gut microbiota by increasing the abundance of the genus Lactobacillus and decreasing the abundance of Dorea, [Eubacterium]_ventriosum_group, Anaerostipes, Collinsella, Coprococcus_1, Ruminiclostridium_5, Ruminococcus_1, Family_XIII_UCG-001, Butyricicoccus, Erysipelotrichaceae_UCG-003, Lachnoclostridium, Faecalibacterium, Lachnospiraceae_UCG-010, Roseburia, Rs-E47_termite_group_norank, Treponema_2 genera. Non-targeted metabolomics analysis showed that ELP reduced arachidonic acid levels. The serum arachidonic acid level was significantly correlated with the abundance of 41 genera, particularly Collinsella and Lactobacillus.. Our study shows that ELP can improve RA joint damage by inhibiting MMPs production and osteoclast activity, and regulating intestinal flora and host metabolites, which provides a novel insight into the ELP in alleviating RA.

Topics: Animals; Arachidonic Acid; Arthritis, Experimental; Arthritis, Rheumatoid; DNA, Ribosomal; Extracellular Signal-Regulated MAP Kinases; Gastrointestinal Microbiome; Ligands; Matrix Metalloproteinase 1; Matrix Metalloproteinase 13; Matrix Metalloproteinase 3; NF-kappa B; Osteoprotegerin; Rats; Tartrate-Resistant Acid Phosphatase

Lamiophlomisrotata (Benth.) Kudo. has been used to treat trauma bleeding, rheumatism, yellow water disease in traditional Chinese medicine.. The aim of this work was to evaluate the anti-rheumatoid arthritis (RA) activities and underlying mechanisms of the total iridoid glucosides (TIG) from Lamiophlomisrotata (Benth.) Kudo.. The chemical constituents of TIG was analyzed by high-performance liquid chromatography (HPLC) with seven reference compounds (penstemonoside, chlorotuberside, shanzhiside methyl ester, phloyoside, 7-epliamalbide, phlorigidoside C and lamalbide). The anti-rheumatoid arthritis effects of TIG were investigated by arthritis indexes and paw swelling degrees, as well as histopathological and Micro-CT analysis in adjuvant-induced arthritis (AIA) rats. The impacts of TIG on the level of inflammatory cytokines (IL-1β, TNF-α, IL-6, IFN-γ, IL-17 and IL-10), and the regulation of OPG/RANKL/NF-κB pathways were determined by the ELISA and western blot, respectively.. TIG significantly reduced the arthritis indexes and paws swelling in AIA rats, attenuated the inflammation and bone destruction in joint tissues, reduced the generation of pro-inflammatory cytokines IL-1β, TNF-α, IL-6, IFN-γ and IL-17, as well as increased the generation of anti-inflammatory cytokine IL-10 in serum. Moreover, TIG markedly inhibited the expression of p-IKK-α, p-IκB and p-p65, and decreased the ratio of OPG/RANKL in the synovial tissues.. TIG possessed significant anti-RA activities on adjuvant-induced arthritis, which might be ascribed to the regulation of inflammatory cytokines IL-1β, TNF-α, IL-6, IFN-γ IL-17 and IL-10, as well as inhibition of OPG/RANKL/NF-κB signaling pathways.

Topics: Animals; Antirheumatic Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Cytokines; Female; Inflammation; Iridoid Glycosides; Lamiaceae; NF-kappa B; Osteoprotegerin; RANK Ligand; Rats; Rats, Sprague-Dawley; Signal Transduction

About half of RA patients treated with TNFα inhibitors either do not respond or lose their initial therapeutic response over time. The clinical response is measured by reduction in DAS28, which primarily reflects inflammation. However, other effects of TNFα inhibitors, such as impact on bone erosion, are not assessed by DAS28. We aimed to examine the effect of TNFα inhibitors on bone density, bone biomarkers and cytokine production in responder and non-responder patients and assessed mechanisms of action.. BMD in the lumbar spine and femur neck of 117 RA patients was measured by DEXA scan. Bone turnover biomarkers CTX, osteoprotegerin (OPG), osteocalcin and RANKL were measured by ELISA. Levels of 16 cytokines in plasma and in tissue culture supernatants of ex vivo T cells were measured by multiplex assays and ELISA. The effect of treatment with TNFα inhibitors on blood mononuclear cell (MNC) differentiation to osteoclast precursors (OCP) was measured flow cytometry and microscopy.. TNFα inhibitors improved lumbar spine BMD but had modest effects on blood bone biomarkers, irrespective of patients' clinical response. Blood OCP numbers and the ability of monocytes to differentiate to OCP in vitro declined after treatment. Treatment also reduced RANK expression and IL-20 production. BMD improvement correlated with reduced levels of IL-20 in responder patients.. This study reveals that TNFα inhibitors reduce lumbar spine bone loss in RA patients irrespective of changes in DAS28. The reduction in bone loss is associated with reduction in IL-20 levels in responder patients.

Topics: Absorptiometry, Photon; Adult; Arthritis, Rheumatoid; Bone Remodeling; Bone Resorption; Cell Differentiation; Female; Humans; Interleukins; Lumbar Vertebrae; Male; Osteocalcin; Osteoprotegerin; Patient Acuity; Treatment Outcome; Tumor Necrosis Factor Inhibitors

To analyze the association between serum levels of osteoprotegerin (OPG) and Dickkopf-related protein 1 (DKK-1) and the annual percent change (Δ%) in bone mineral density (BMD) in patients with tightly controlled rheumatoid arthritis (RA).. Observational mixed-study. RA patients followed-up with a tight-control strategy were included. Bone densitometries were performed at baseline (T0) and follow-up (T1) and serum levels of OPG and DKK-1 were measured by ELISA also in T0 and T1; additional clinical variables included disease activity measures, and treatment for RA and osteoporosis. Descriptive bivariate and multivariate analyses, stratified by gender, were performed.. We included 97 RA patients (70% female, with a mean age of 53 years, and 76% with low activity by DAS28); 95% were treated with DMARDs and 37% with anti-osteoporotic drugs. Mean time between T0 and T1 was 2.7 years. Most patients had their BMD improved. The mean Δ%BMD was +0.42% for lumbar spine, +0.15% for femoral neck and +0.91% for total femur. In men, baseline OPG was significantly associated with higher BMD loss (β coefficient -0.64) at the femoral neck. In women, DKK-1 was associated with higher BMD loss at the femoral neck (β coefficient -0.09), and total femur (β coefficient -0.11); however, DKK-1 was associated with lower BMD loss at the lumbar spine (β coefficient 0.06).. In tightly controlled RA patients, we have found no evidence of bone loss. The role of DKK1 and OPG seems small and might be related to sex and location.

Topics: Adult; Aged; Arthritis, Rheumatoid; Bone Density; Female; Humans; Intercellular Signaling Peptides and Proteins; Male; Middle Aged; Osteoprotegerin

Objective To investigate the therapeutic effect of Bushentongluo recipe (BSTL) on bone destruction and its inhibiting effect on NF-κB/RANK/RANKL pathway in collagen-induced arthritis (CIA) rats. Methods SD rats were randomly divided into blank control group, CIA model group, methotrexate (MTX, 1 mg/kg) group, BSTL 0.5 g/kg and 2 g/kg groups, with 10 rats in each. Except the control group, the other rats were injected subcutaneously with type 2 collagen(Col2) at the base of the tail to establish CIA models. After exposure to MTX or BSTL recipe for consecutive 28 days, the pathological change of joint tissues was examined by HE staining. Immunohistochemistry was used to detect NF-κB p65 expression in synovial tissues. The cytokines and anti-Col2 levels were analyzed by ELISA. Western blotting was used to detect the expression of RANKL, RANK and osteoprotegerin (OPG) proteins. Results Compared with the CIA model group, the rats treated with 2 g/kg BSTL for 28 days had lower paw volume, arthritis index (AI), serum levels of IL-1β, IL-18, TNF-α, anti-Col2-IgG, anti-Col2-IgG2a, RANK and RANKL, and higher level of serum OPG. Besides, Western blotting showed that the expression of NF-κB p65, RANK and RANKL proteins decreased, but the expression of OPG protein increased in BSTL 2 g/kg group. Conclusion BSTL can alleviate the rheumatoid arthritis by down-regulating the expression of NF-κB p65, RANKL, RANK proteins, up-regulating OPG protein, and inhibiting systemic inflammation.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; NF-kappa B; Osteoprotegerin; RANK Ligand; Rats; Rats, Sprague-Dawley; Synovial Membrane

Interleukin (IL)-17A signaling pathway plays a critical role in the initiation and progression of rheumatoid arthritis (RA) and represents a viable target for RA therapy. Cyanidin, a flavonoid compound, is a novel inhibitor of IL-17A/IL-17RA (receptor subunit A) interaction in several inflammatory diseases. However, the therapeutic efficacy of cyanidin on IL-17A cytokine signaling induced monocyte migration and fibroblast-like synoviocytes (FLS) released RANKL mediated osteoclastogenesis in RA has not yet been deciphered. In the present study, cyanidin impeded IL-17A induced migration of monocytes isolated from adjuvant-induced arthritic (AA) rats. At the molecular level, cyanidin blocked the activation of p38MAPK signaling in response to IL-17A. Importantly, cyanidin downregulated IL-17A induced expression of HSP27, CXCR4, and CCR7 in AA monocytes via modulating IL-17/p38 MAPK signaling axis. Alternatively, cyanidin significantly suppressed the formation of matured osteoclasts and bone resorption in a coculture system consisting of IL-17 treated AA-FLS and rat bone marrow-derived monocytes/macrophages. Further, cyanidin significantly inhibited the expression of RANKL and increased the expression of OPG in AA-FLS via blunted activation of IL-17A/STAT-3 signaling cascade. Interestingly, cyanidin impaired IL-17A induced overexpression of IL-17RA. Taken together, our study proposes a novel therapeutic function of cyanidin towards targeted inhibition of IL-17A/IL-17RA signaling mediated disease severity and bone erosion in RA.

Topics: Animals; Anthocyanins; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Cell Differentiation; Cell Movement; Cell Survival; Down-Regulation; Female; HSP27 Heat-Shock Proteins; Interleukin-17; Male; Mice; Models, Biological; Monocytes; Osteoclasts; Osteogenesis; Osteoprotegerin; p38 Mitogen-Activated Protein Kinases; Phosphorylation; RANK Ligand; Rats, Wistar; Receptors, CCR7; Receptors, CXCR4; Receptors, Interleukin-17; Signal Transduction; Small Molecule Libraries; STAT3 Transcription Factor

Fibroblast-derived exosomes have been reported to transfer microRNAs to recipient cells, where they regulate target gene expression, which is of interest for understanding the basic biology of inflammation, tissue homeostasis, and development of therapeutic approaches. Initial microarray-based analysis carried out in this study identified the rheumatoid arthritis (RA)-related differentially expressed gene pyruvate dehydrogenase kinase 4 (PDK4). Subsequently, the upstream regulatory microRNA-106b (miR-106b) of PDK4 was predicted with bioinformatic analyses. A collagen-induced arthritis (CIA)-induced mouse model was established, and exosomes were isolated from synovial fibroblasts (SFs) and transferred into chondrocytes to identify the role of exosomes in rheumatoid arthritis (RA). We found that PDK4 was poorly expressed in RA cartilage tissues and chondrocytes, while miR-106b was highly expressed in RA SFs and SF-derived exosomes. Notably, PDK4 was confirmed as a target gene of miR-106b. Over-expression of PDK4 promoted the proliferation and migration abilities of chondrocytes and inhibited their apoptosis as well as affected the receptor activator of nuclear factor kappa B ligand (RANKL)/RANK/osteoprotegerin (OPG) system. Meanwhile, miR-106b was delivered from SFs to chondrocytes through exosomes, which suppressed chondrocyte proliferation and migration and accelerated apoptosis as well as affected the RANKL/RANK/OPG system via down-regulation of PDK4. Furthermore, in vivo results validated that miR-106b inhibition could relieve CIA-induced RA. Taken together, SF-derived exosomal miR-106b stimulates RA initiation by targeting PDK4, indicating a physiologically validated potential approach for the prevention and treatment of RA. KEY MESSAGES: PDK4 is decreased in chondrocytes of RA, while miR-106b is increased in SFBs. PDK4 promotes proliferation and migration of chondrocytes. miR-106b could target 3'UTR of PDK4 gene. SFB-exosomal miR-106b inhibits proliferation and migration of chondrocytes. Inhibition of miR-106b attenuates RA progression in a CIA mouse model.

Topics: Animals; Ankle Joint; Arthritis, Experimental; Arthritis, Rheumatoid; Cartilage, Articular; Cell Movement; Cell Proliferation; Cells, Cultured; Chondrocytes; Coculture Techniques; Down-Regulation; Exosomes; Fibroblasts; Humans; Male; Mice, Inbred DBA; MicroRNAs; Osteoprotegerin; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Synovial Membrane

Optineurin (OPTN) is an autophagy adaptor/receptor that acts as an intrinsic negative regulator of osteoclast differentiation. RANKL expressed by rheumatoid arthritis synovial fibroblasts (RASFs) is primarily responsible for the development of bone erosions in patients with RA. The aim of the present study was to explore the role of OPTN in the pathogenesis of joint destruction in RA.. RASFs were left untreated or incubated with tumor necrosis factor (TNF) or interferon-γ (IFNγ), and expression of OPTN by RASFs was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Expression of RANKL and osteoprotegerin (OPG) was evaluated in cultures of OPTN-reduced RASFs with or without TNF or IFNγ treatment. OPTN-reduced RASFs were cocultured with monocytes and stained for tartrate-resistant acid phosphatase (TRAP). IκBα, NF-κB1, and RelA protein levels were measured to evaluate NF-κB signaling. Expression of messenger RNA (mRNA) for matrix metalloproteinase 3 (MMP3), interleukin-6 (IL6), GATA binding protein 3 (GATA3), carbohydrate sulfotransferase 15 (CHST15), hyaluronan synthase 1 (HAS1), and GATA1 was analyzed by RT-qPCR.. In RASFs incubated with TNF or IFNγ, OPTN expression was up-regulated and RANKL expression was increased, and these effects were further pronounced in OPTN-reduced RASFs (all P < 0.05 versus controls). OPG mRNA levels remained unchanged. Monocytes cocultured with OPTN-reduced RASFs differentiated to a greater extent into TRAP+ multinucleated cells compared to monocytes cocultured with control RASFs (P < 0.05). IκBα degradation and nuclear NF-κB1 expression following TNF treatment were both prolonged in OPTN-reduced RASFs (each P < 0.05 versus controls). MMP3 mRNA levels were up-regulated, while GATA3, CHST15, and HAS1 mRNA levels were down-regulated in OPTN-reduced RASFs (each P < 0.05 versus controls).. OPTN plays a protective role in RA when it is up-regulated in RASFs in the presence of proinflammatory cytokines. Absence of OPTN might worsen RA by generating a joint-destructive state, as indicated by evidence of increased RANKL expression on RASFs and subsequent osteoclast differentiation.

Topics: Arthritis, Rheumatoid; Blotting, Western; Cell Cycle Proteins; Cell Differentiation; Coculture Techniques; Fibroblasts; GATA1 Transcription Factor; GATA3 Transcription Factor; Humans; Hyaluronan Synthases; Interferon-gamma; Interleukin-6; Matrix Metalloproteinase 3; Membrane Glycoproteins; Membrane Transport Proteins; Monocytes; NF-kappa B p50 Subunit; NF-KappaB Inhibitor alpha; Osteoprotegerin; RANK Ligand; Reverse Transcriptase Polymerase Chain Reaction; Sulfotransferases; Synovial Membrane; Tartrate-Resistant Acid Phosphatase; Transcription Factor RelA; Tumor Necrosis Factor-alpha

To detect the effect of interleukin (IL)-34 on the secretion of Receptor activator of nuclear factor kappa-B ligand (RANKL)/Osteoprotegerin (OPG) and Matrix metalloproteinase (MMP)-3 by fibroblast-like synoviocytes (FLS) and peripheral blood mononuclear cells (PBMCs) of rheumatoid arthritis (RA) patients and to investigate whether the effect is mediated by IL-17.. RA-FLS and RA-PBMCs were stimulated with recombinant human (rh) IL-34, with or without the IL-17 inhibitor Plumbagin. The supernatant of the culture medium was collected and the levels of RANKL, OPG, and MMP-3 were detected by enzyme-linked immunosorbent assay (ELISA).. RhIL-34 promoted RANKL secretion and inhibited OPG secretion in RA-FLS. The effect was weakened by the addition of the IL-17 inhibitor. In contrast, rhIL-34 had no significant effect on MMP-3 secretion by FLS. RhIL-34 elevated the secretion of RANKL by RA-PBMCs but not by healthy-PBMCs. Furthermore, the secretion of RANKL by RA-PBMCs reduced after the addition of the IL-17 inhibitor. OPG secretion by both RA-FLS and FLS from healthy controls was inhibited by rhIL-34, but were elevated after the addition of the IL-17 inhibitor. RhIL-34 had no significant effect on MMP-3 secretion by both RA-PBMCs and healthy-PBMCs.. IL-34 enhances RANKL/OPG expression by RA-FLS and RA-PBMCs, and this effect is, indirectly, mediated by IL-17. This cytokine is therefore likely to to play an important role in local joint destruction and systemic osteoporosis in RA, and is therefore a potential therapeutic target for the treatment of this disease.

Topics: Arthritis, Rheumatoid; Female; Fibroblasts; Humans; Interleukin-17; Interleukins; Leukocytes, Mononuclear; Male; Matrix Metalloproteinase 3; Middle Aged; Osteoprotegerin; RANK Ligand; Synoviocytes

The present study evaluated the protective effects of pseurotin A against inflammation and the destruction of cartilage in a rat model of rheumatoid arthritis (RA). RA was induced by intradermal injections of Freund's complete adjuvant (1 mg/mL), and the treatment with pseurotin A (50 and 100 mg/kg, p.o.) was administered over 1 week. The effects of pseurotin A were assessed by estimating hind paw volume (HPV) and determining the levels of inflammatory mediators in the serum and synovial fluid of collagen-induced arthritis (CIA)-induced RA rats. Western blot and histopathological assays were performed to assess changes in synovial tissues. Additionally, in vitro analyses of receptor activator of nuclear factor-kappa-Β ligand (RANKL)-stimulated RAW264.7 cells treated with pseurotin A at different concentrations (1, 10, and 100 µg/mL) were conducted to assess the effects of pseurotin A on apoptosis ratio, real-time polymerase chain reaction data, and tartrate-resistant acid phosphatase staining. Compared to the RA group, treatment with pseurotin A significantly decreased HPV and reduced the levels of inflammatory mediators in the synovial fluid and blood. Additionally, pseurotin A ameliorated the protein expressions of osteoprotegerin, nuclear factor of activated T-cells, nuclear factor-kappa beta (NF-κB), IκBα, extracellular signal regulated kinase, and P38 as well as histopathological changes in the synovial tissue of CIA-induced RA rats. The in vitro findings revealed that pseurotin A treatment did not alter the apoptosis ratio in RANKL-stimulated RAW264.7 cells but significantly reduced the mRNA expressions of calcitonin receptor, NF-κB, and matrix metallopeptidase-9. The present findings suggest that pseurotin A ameliorated the differentiation of osteoclasts and the destruction of cartilage in RA rats via regulation of the mitogen-activated protein kinase/RANKL/NF-kB pathway.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cartilage; Cell Differentiation; Cytokines; Dinoprostone; Disease Models, Animal; Joints; Male; Mice; Mitogen-Activated Protein Kinases; Osteoclasts; Osteoprotegerin; Protective Agents; Pyrrolidinones; RANK Ligand; Rats, Sprague-Dawley; RAW 264.7 Cells; Signal Transduction

Patients with rheumatoid arthritis (RA) may display atypical CD21

Topics: Animals; Arthritis, Rheumatoid; Ataxia Telangiectasia Mutated Proteins; B-Lymphocytes; Bone Density; Bone Resorption; Cell Survival; Humans; Immunoglobulins; Joints; Lymphocyte Count; Mice; Middle Aged; Osteogenesis; Osteoprotegerin; Phenotype; RANK Ligand; Receptors, Complement 3d; Recombination, Genetic

The mechanisms responsible for increased cardiovascular risk in patients with rheumatoid arthritis (RA) involve local and systemic inflammatory processes. We aimed to compare inflammatory markers and mortality risk in patients with acute coronary syndrome (ACS) with and without RA. The study involved 95 ACS patients (46 with RA and 49 without RA) and 40 healthy controls. Serum levels of Receptor Activator of Nuclear Factor Kappa B Ligand (sRANKL), Osteoprotegerin (sOPG), high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity Tropinin I (hs-TnI) were tested in all participants. Additionally, ACS patients were assessed on RANKL expression (exRANKL) on coronary arteries and mortality risk on the Global Registry of Acute Coronary Events scale (GRACE). exRANKL was established in 35 (76%) ACS patients with RA, vs. 19 (39%) patients without RA, p < 0.001. RA patients had significantly higher levels of sRANKL and sOPG at 24 h and 48 h compared to ACS patients without RA and healthy controls (sRANKL 24 h: 121.33 vs. 51.67 vs. 36.94, p = 0.019; sRANKL 48 h: 89.21 vs. 36.95 vs. 36.94, p = 0.004; sOPG 24 h: 207.71 vs. 69.39 vs. 111.91, p < 0.001; sOPG 48 h: 143.36 vs. 69.38 vs. 111.91, p < 0.001). RA patients had significantly higher RANKL:OPG ratio at 48 h (0.062 vs. 0.53 vs. 0.33, p < 0.001), hs-CRP (28.82 vs. 23.67 vs. 2.60, p < 0.001) and hs-TnI (0.90 vs. 0.76 vs. 0.012). GRACE risk score was significantly higher in RA patients vs. those without RA (140.45 vs. 125.50, p = 0.030) and correlated with exRANKL, RANKL:OPG, hs-CRP, and hs-TnI. Our results indicate that exRANKL, inflammatory markers and mortality risk are amplified in ACS patients with RA compared to ACS patients without RA.

Topics: Acute Coronary Syndrome; Aged; Arthritis, Rheumatoid; Biomarkers; C-Reactive Protein; Case-Control Studies; Female; Humans; Inflammation Mediators; Male; Middle Aged; Osteoprotegerin; Prognosis; RANK Ligand; Risk Assessment; Risk Factors; Troponin I

BACKGROUND Osteoprotegerin (OPG) inhibits bone resorption and binds with strong affinity to receptor activator of NF κB ligand (RANKL), thereby preventing RANKL from binding to its receptor RANK. Osteoclasts have documented effects on bone erosion of rheumatoid arthritis (RA). The aim of this study was to examine the role of miR-145-5p in the regulation of RA osteoclast differentiation and bone erosion. MATERIAL AND METHODS Expression of microRNA-145-5p in human peripheral blood mononuclear cells (PBMC) and synovial tissue was assayed by real-time polymerase chain reaction (RT-PCR). OPG, RANK, and RANKL expression in RAW-264.7 cells was examined by RT-PCR and Western blot analysis. Osteoclast formation was detected by tartrate-resistant acid phosphatase (TRAP) staining. The effect of miR-145-5p on predicted target mRNAs was examined by luciferase reporter assays. Collagen-induced arthritis (CIA) was induced by injecting DBA/1 mice with bovine type II collagen (CII), and miR-145-5p agomir was administered by intravenous injection. Morphological changes in the CIA joint were assessed by micro-computed tomography (CT) and histopathology. RESULTS miR-145-5p levels significantly increased in RA PBMC and synovial tissue compared with normal PBMC and osteoarthritis (OA) tissue. After transfection of RAW-264.7 cells with miR-145-5p, RANK and RANKL expression increased significantly, while OPG expression decreased significantly. TRAP staining results showed osteoclast numbers increased. Micro-CT analysis of the arthritic joints showed that the miR-145-5p agomir caused bone erosion in mice, and histopathological analysis revealed that miR-145-5p agomir aggravates cartilage erosion. CONCLUSIONS Our findings indicate that administration of miR-145-5p aggravates joint erosion in CIA mice. This suggests that miR-145-5p is a potential target for the treatment of RA.

Topics: Adult; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Cattle; Collagen Type II; Female; Humans; Male; Mice; Mice, Inbred DBA; MicroRNAs; Middle Aged; Osteoclasts; Osteoprotegerin; RANK Ligand; RAW 264.7 Cells; Receptor Activator of Nuclear Factor-kappa B; Synovial Membrane; Transfection; Young Adult

Tartrate-resistant acid phosphatase (TRACP)-5b and osteoprotegerin (OPG) are specific and sensitive markers of bone resorption in patients with rheumatoid arthritis (RA) and chronic kidney disease (CKD). The TRACP-5b level is associated with the severity of RA and CKD, while the OPG level is associated with the severity of coronary atherosclerosis and calcification, and can predict a poor outcome in patients with coronary artery disease (CAD). However, the impact of TRACP-5b on coronary atherosclerosis in CAD patients remains unclear.. A total of 71 CAD patients (57 men, 14 women; mean age: 69.0±9.7 years) and 28 age- and gender- matched healthy subjects were investigated. The number of diseased vessels (a marker of the severity of coronary atherosclerosis) and the Gensini score (a marker of the extent of coronary atherosclerosis), as well as the OPG and TRACP-5b levels were measured in CAD patients. The TRACP-5b levels were classified into quartiles.. The TRACP-5b levels were significantly higher in CAD patients than in healthy subjects. Patients with higher TRACP-5b levels had higher OPG levels and Gensini scores than those with lower TRACP-5b levels. Higher TRACP-5b levels were associated with an increased number of diseased vessels. A multivariate linear regression analysis showed that the OPG level and the number of diseased vessels or the Gensini score were significantly and independently associated with the TRACP-5b level.. These data indicate that the TRACP-5b level is significantly associated with the OPG level and with the severity and extent of coronary atherosclerosis in CAD patients.

Topics: Aged; Arthritis, Rheumatoid; Biomarkers; Calcinosis; Case-Control Studies; Coronary Artery Disease; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Multivariate Analysis; Osteoprotegerin; Smoking; Tartrate-Resistant Acid Phosphatase; Treatment Outcome

Osteoporosis (OP) is highly prevalent in rheumatoid arthritis (RA) and is influenced by genetic factors. Single-nucleotide polymorphism (SNP) rs2073618 in the

Topics: Age Factors; Aged; Alleles; Arthritis, Rheumatoid; Bone Density; Case-Control Studies; Female; Genotype; Humans; Mexico; Middle Aged; Osteoporosis; Osteoprotegerin; Polymorphism, Single Nucleotide

To investigate the effect of boldine isolated from Litsea cubeba on collagen-induced arthritis (CIA) rats and explore the molecular mechanism predicted by network pharmacology.. CIA rats were orally administered with boldine. The bone destruction of paws was analyzed by histologic examination, tartrate-resistant acid phosphatase (TRACP) staining and micro-computed tomography. Prediction of signal pathway associated with boldine network molecules and CIA genes was applied by the network pharmacology analysis. The expressions of osteoprotegerin (OPG), receptor activator of nuclear factor-κB (RANK) and its ligand (RANKL) in the ankle were detected by immunohistochemistry. In vitro osteoclasts were cultured in the presence of variable doses of boldine and the RANK expressions were evaluated using Real-time polymerase chain reaction and western blot.. Boldine reduced ankle swelling, alleviated pathological damage and significantly prevented bone destruction in CIA rats. Consistent with this, enzyme linked immunosorbent assay revealed boldine decreased serum TRACP5b levels and osteoclast number in the ankle region by TRACP staining from CIA rats. The network pharmacology analysis indicated that RANK signaling in osteoclasts was the most significant canonical pathway associated with boldine network molecules and CIA genes, which was verified by the increased expression of OPG, reduced expression of RANK, RANKL and RANKL/OPG in boldine-treated CIA rats. The in vitro study further confirmed that boldine inhibited osteoclastogenesis by inhibiting the RANKL/RANK signaling pathway.. Taken together, our study first indicates that boldine from Litsea cubeba suppresses osteoclastogenesis, improves bone destruction by down-regulating the OPG/RANKL/RANK signal pathway and may be a potential therapeutic agent for rheumatoid arthritis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aporphines; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Cells, Cultured; Disease Models, Animal; Humans; Litsea; Male; Mice; Mice, Inbred C57BL; Osteogenesis; Osteoprotegerin; RANK Ligand; Rats; Rats, Sprague-Dawley; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction

In rheumatoid arthritis (RA), a disease characterized by bone loss, increased levels of serotonin have been reported. Recent studies have demonstrated a role for circulating serotonin as a regulator of osteoblastogenesis, inhibiting bone formation. Thus, we measured serum serotonin levels (SSL) in a Portuguese sample of 205 RA patients and related these to anthropometric variables, disease parameters, serum bone biomarkers, and bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry at several sites (total proximal femur, lumbar spine, left hand, and left second proximal phalange). SSL were inversely associated with body mass index (BMI) in RA women (r = - 0.218; p = 0.005), independent of exposure to biologics and/or bisphosphonates. Among biologic naïves, there was an inverse association between SSL and osteoprotegerin in RA women (r = - 0.260; p = 0.022). Serum β-CTX and dickkopf-1 were strongly associated with SSL in RA men not treated with bisphosphonates (r = 0.590; p < 0.001/r = 0.387; p = 0.031, respectively). There was also an inverse association between SSL and sclerostin in RA men (r = - 0.374; p < 0.05), stronger among biologic naïve or bisphosphonates-unexposed RA men. In crude models, SSL presented as a significant negative predictor of total proximal femur BMD in RA women as well as in postmenopausal RA women. After adjustment for BMI, disease duration, and years of menopause, SSL remained a significant negative predictor of total proximal femur BMD only in postmenopausal RA women. Our data reinforce a role, despite weak, for circulating serotonin in regulating bone mass in RA patients, with some differences in terms of gender and anatomical sites.

Topics: Arthritis, Rheumatoid; Body Mass Index; Bone Density; Female; Humans; Male; Osteoprotegerin; Serotonin

Bone erosion is a central feature of rheumatoid arthritis (RA) that is characterized by the infiltration of the synovial lining by osteoclasts and lymphocytes. In the present study, swertiamarin a major secoiridoid glycoside was evaluated for anti-osteoclastogenic property to prevent bone erosion in Freund's complete adjuvant (FCA) induced in-vivo model, in-vitro osteoblast and osteoclasts as well as in co-culture system and in-silico molecular docking analysis. The swertiamarin treatment decreased the expression of TRAP, RANKL, and RANK levels and increased the levels of OPG levels significantly in both in vitro and in vivo models. In in vitro, the compound treatment significantly increased the cell proliferation and ALP levels in osteoblast cells; the high proliferation (153.8600±5.23%) and ALP release (165.6033±4.13%) were observed at 50μg/ml concentration of swertiamarin treatment. At the same time the treatment decreased the TRAP positive cells in osteoclast cells; the high reductions of TRAP positive cells (39.32±3.19%) were observed at 50μg/ml of swertiamarin treatment. The treatment modulated the levels of pro-inflammatory cytokines, MMPs and NF-κB levels in osteoblast and osteoclast co-culture system. In in silico analysis swertiamarin had affinity towards the proteins RANK, RANKL and OPG residues with low binding energy -4.5, -3.92 and -5.77kcal/mol respectively. Thus, the results of this study revealed the anti-osteoclastogenic activity of swertiamarin on the prevention of bone destruction.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Cell Proliferation; Cells, Cultured; Cytokines; Disease Models, Animal; Female; Humans; Inflammation Mediators; Iridoid Glucosides; Lymphocytes; Mice; Osteoclasts; Osteoprotegerin; Phytosterols; Protein Binding; Pyrones; RANK Ligand; Rats; Rats, Sprague-Dawley; Receptor Activator of Nuclear Factor-kappa B; Synovial Membrane

Astragalus membranaceus Bunge is one of the oldest and most frequently used crude herbs in traditional Chinese medicine. The total flavonoids of Astragalus (TFA) are the main active components isolated from Astragalus membranaceus Bunge. Our recent study has shown its potential immunomodulatory and anti-inflammatory effects in vivo and in vitro. However, its anti-arthritic effects and mechanisms of action involved have not been elucidated. The aim of this study was to evaluate the protective effects and possible mechanisms of TFA on Freund's complete adjuvant (FCA)-induced arthritis in rats.. Wistar rats were intradermally injected FCA into the right hind metatarsal footpads to establish adjuvant-arthritic model. The rats were intragastrically administered daily with TFA at 25, 50 and 100mg/kg for 28days after FCA induction. Body weight, primary paw swelling, arthritis index, thymus and spleen indices were measured. The levels of serum tumor necrosis factor (TNF)-α, interleukin (IL)-1β, prostaglandin (PG)E. These results suggest that TFA exerts potential protective effects against FCA-induced arthritis in rats by regulating OPG/RANKL/NF-κB pathway.

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Astragalus Plant; Dinoprostone; Flavonoids; Humans; Interleukin-1beta; Male; Medicine, Chinese Traditional; NF-kappa B; Osteoprotegerin; RANK Ligand; Rats; Rats, Wistar; Synovial Membrane; Tumor Necrosis Factor-alpha

Topics: Adult; Aged; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Female; Humans; Male; Middle Aged; Osteoprotegerin; Prognosis; Remission Induction

To determine mechanisms involved in endothelial dysfunction (ED) during the course of arthritis and to investigate the link between cytokines, chemokines and osteoprotegerin.. Experiments were conducted on aortic rings at day 4 (preclinical), day 11 (onset of disease), day 33 (acute disease) and day 90 (chronic disease) after adjuvant-induced arthritis (AIA) in Lewis rats. At day 4, the unique vascular abnormality was a reduced norepinephrine-induced constriction. At day 11, endothelial function assessed by the relaxation to acetylcholine was normal despite increased cyclo-oxygenase-2 activity (COX-2) and overproduction of superoxide anions that was compensated by increased nitric oxide synthase (NOS) activity. At day 33, ED apparition coincides with the normalization of NOS activity. At day 90, ED was only observed in rats with a persisting imbalance between endothelial NOS and COX-2 pathways and higher plasma levels of IL-1β and TNFα. Plasma levels of IL-1β, TNFα and MIP-1α negatively correlated with Ach-induced relaxation throughout the course of AIA.. Our data identified increased endothelial NOS activity as an important compensatory response that opposes the ED in the early arthritis. Thereafter, a cross-talk between endothelial COX-2/NOS pathways appears as an important element for the occurrence of ED. Our results encourage determining the clinical value of IL-1β, TNFα and MIP-1α as biomarkers of ED in RA.

Topics: Acetylcholine; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Biomarkers; Chemokines; Cyclic N-Oxides; Cyclooxygenase 2; Disease Progression; Endothelium, Vascular; Immunization; Inflammation; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase Type III; Nitrobenzenes; Nitroprusside; Osteoprotegerin; Radiography; Rats, Inbred Lew; Spin Labels; Sulfonamides; Superoxides; Time Factors; Vasoconstriction; Vasodilation

Secondary osteoporosis is a frequent complication of rheumatoid arthritis (RA) and the result of an imbalance of catabolic and anabolic mechanisms of bone metabolism. The effects of serial low-dose radon and hyperthermia (LDRnHT) exposure in a therapeutic adit (12 applications in 3 weeks) on the serum levels of the cytokines osteoprotegerin (OPG), receptor activator of NF kappa-B ligand (RANKL), tumor necrosis factor-α (TNF-α), and also on the RANKL/OPG ratio were investigated in 25 RA patients and an age-matched control of 24 patients with osteoarthritis (OA). Cytokine measurements were performed at baseline and after completion of LDRnHT. Anti-CCP antibodies (ACPA) were measured in RA patients in parallel. Medication in both groups was limited to non-steroidal anti-inflammatory drugs, and low-dose prednisolone (16 of 24 RA patients) as needed. RA and OA patients showed a significant decrease of TNF-α levels (p < 0.001). Both groups showed significantly decreased levels of RANKL (RA: p < 0.001, OA: p < 0.01). Only the RA patients presented a significant increase of OPG (p < 0.01) and decrease of the RANKL/OPG ratio (p < 0.01), and the ACPA levels (p < 0.001). LDRnHT results in a reduction of osteocatabolic and an increase of osteoanabolic cytokines, which represents the molecular basis for inhibiting osteoclastic activity in secondary osteoporosis and explains in part the effect of LDRnHT this physical therapy modality in a key inflammatory disease. Although reduced ACPA levels were observed under the therapy and although this could potentially contribute to an osteoprotective effect, in this case, it is rather uncertain as the reduction was only minor in magnitude.

Topics: Aged; Arthritis, Rheumatoid; Female; Humans; Hyperthermia, Induced; Male; Middle Aged; Osteoarthritis; Osteoprotegerin; Radon; RANK Ligand; Treatment Outcome; Tumor Necrosis Factor-alpha

To evaluate the effect of anti-TNF treatments on bone mineral density (BMD), bone remodelling markers (BRM) and receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG) in patients with chronic inflammatory joint diseases.. A longitudinal prospective study was performed under clinical practice conditions on 31 patients diagnosed of rheumatoid arthritis, psoriatic arthropathy and ankylosing spondylitis who had received treatment with anti-TNF alpha drugs for one year. BMD, OPG and RANKL soluble form (sRANKL) were studied at the onset and end of the study. During the study (0, 3, 6, 9 and 12 month), disease activity (SDAI, BASDAI and CRP), functional capacity (HAQ, BASFI), BRM and vitamin D were studied.. BMD was not modified after one year of treatment. The patients who took corticosteroids had a mean bone mass loss of 3% in the lumbar spine (±1.6, P=.02). In regards to the BRM, did not experience significant changes over the course of the study. Disease activity, both SDAI (P=.002) and BASDAI (P=.002), decreased. OPG was maintained without changes during the year of treatment while both the sRANKL (0.28±0.22, P=.013) and sRANKL/OPG ratio significantly decreased (0.04±0.03, P=.031).. The patients being treated with anti-TNF did not present with a significant loss of DMO during the study (one year), at the same time experiencing an improvement in disease activity. This protection has been clearer in the responding patients.

Topics: Adalimumab; Adult; Aged; Anti-Inflammatory Agents; Arthritis, Psoriatic; Arthritis, Rheumatoid; Biomarkers; Bone Density; Bone Remodeling; Chronic Disease; Etanercept; Female; Humans; Infliximab; Longitudinal Studies; Male; Middle Aged; Osteoprotegerin; Prospective Studies; RANK Ligand; Spondylitis, Ankylosing; Treatment Outcome; Tumor Necrosis Factor-alpha

Osteoprotegerin (OPG), receptor activator of nuclear factor-ΚB ligand (RANKL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) have been involved in rheumatoid arthritis (RA) pathophysiology. In this study, we assessed messenger RNA (mRNA) expression of these molecules by qPCR in peripheral blood from 26 patients with RA (12 of them with ischemic heart disease -IHD) and 10 healthy controls. Correlation coefficients between OPG, RANKL and TRAIL expression levels in RA patients and their clinical and demographic characteristics were also evaluated. Whereas OPG and OPG/TRAIL ratio expression were significantly increased in RA patients compared to controls (fold change = 1.79, p = 0.013 and 2.07, p = 0.030, respectively), RANKL/OPG ratio was significantly decreased (fold change = 0.50, p = 0.020). No significant differences were found between patients and controls in RANKL and TRAIL expression. Interestingly, TRAIL expression was significantly higher in RA patients with IHD compared to those without IHD (fold change = 1.46, p = 0.033). Moreover, biologic disease-modifying antirheumatic drugs (DMARDs) significantly decreased RANKL expression in RA patients (p = 0.016). Our study supports an important role of OPG and TRAIL in RA. Furthermore, it highlights an effect of biologic DMARDs in the modulation of RANKL.

Topics: Antirheumatic Agents; Arthritis, Rheumatoid; Female; Gene Expression Regulation; Humans; Male; Myocardial Ischemia; Osteoprotegerin; RANK Ligand; TNF-Related Apoptosis-Inducing Ligand

Cytokines play a key role in the bone destruction of rheumatoid arthritis (RA). Interleukin-21 (IL-21) promotes osteoclastogenesis in RA in a receptor activator of nuclear factor-κB ligand (RANKL)-dependent way. Whether IL-21 is capable of promoting osteoclastogenesis directly in the absence of RANKL remains unknown. In the present study, we examined the osteoclastogenic activity of IL-21 in RAW264.7 cells in the absence of RANKL. We found that IL-21 enhanced osteoclastogenesis and this was demonstrated by increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive stained, multinucleated cells compared with the negative control. Western blot analysis and immunocytochemistry showed the positive expression of calcitonin receptor (CTR) in the IL-21 group. RT-PCR and RT-qPCR also verified the increased mRNA expression of CTR and cathepsin K in the IL-21 group compared with the negative control. The scanning electronic microscope images showed a few resorption pits on the bone slices cultured with IL-21. The phosphoinositide 3-kinase (PI3K)/AKT pathway inhibitor LY294002 significantly suppressed IL-21-induced osteoclastogenesis. Taken together, these findings suggest that IL-21 has direct osteoclastogenic potential independently of RANKL. IL-21 may promote osteoclastogenesis through the PI3K/AKT signaling pathway. Therapy targeting IL-21 may be of value in preventing bone erosions in patients with RA.

Topics: Adult; Animals; Arthritis, Rheumatoid; Bone Resorption; Cathepsin K; Female; Humans; Interleukins; Leukocytes, Mononuclear; Male; Mice; Osteoclasts; Osteogenesis; Osteoprotegerin; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; RANK Ligand; RAW 264.7 Cells; Receptor Activator of Nuclear Factor-kappa B; Receptors, Calcitonin; Receptors, Interleukin; Signal Transduction

The receptor activator of nuclear factor κB ligand (RANKL)/receptor activator of nuclear factor κB (RANK)/osteoprotegerin (OPG) system plays a key role in rheumatoid arthritis (RA)-associated bone erosion. The upregulation of the RANKL/OPG ratio promotes bone erosion. The objective of this study is to explore the effects of iguratimod, a small-molecule disease-modifying antirheumatic drug (DMARD), alone or in combination with methotrexate (MTX), on RANKL and OPG expression in RA. We performed an enzyme-linked immunosorbent assay (ELISA) to investigate the modulatory effects of iguratimod, MTX, or their combination on serum RANKL and OPG levels of patients with RA before and after treatment for 12 and 24 weeks. Furthermore, fibroblast-like synoviocytes (FLS) from patients with RA were interleukin (IL)-1β-stimulated and then treated with different concentrations of iguratimod, MTX, or both, and RANKL and OPG expressions were investigated by using ELISA, quantitative real-time polymerase chain reaction (qPCR) and western blot analysis. We found that RANKL levels and the RANKL/OPG ratio significantly decreased in both serum and IL-1β-induced RA FLS after treatment. Moreover, combination therapy with iguratimod and MTX showed an even stronger inhibition than each drug alone did. Our results suggest that iguratimod and MTX, especially in combination, efficaciously protected against bone erosion by suppressing the production of RANKL.

Topics: Adult; Arthritis, Rheumatoid; Blotting, Western; Chromones; Enzyme-Linked Immunosorbent Assay; Female; Fibroblasts; Humans; Interleukin-1beta; Male; Methotrexate; Middle Aged; Osteoprotegerin; RANK Ligand; Real-Time Polymerase Chain Reaction; RNA, Messenger; Sulfonamides; Synoviocytes

To investigate the association of osteoproterin (OPG) gene polymorphisms 163A/G (rs3102735), 245T/G (rs3134069) with susceptibility to rheumatoid arthritis (RA) in Chinese Han population.. To study the correlation between the disease of rheumatoid arthritis (RA) in Chinese Han group and the association of osteoproterin (OPG) gene polymorphisms 163A/G(rs3102735) and 245T/G (rs3134069). Approaches: 205 RA patients and 171 healthy control subjects were participated into this study. Genotype analysis was conducted by polymerase chain reaction-based restriction fragment length polymorphism and was subsequently confirmed by DNA sequencing. Odd ration (OR) and 95% confidence intervals (95% CI) were calculated for the risk of genotype and allele.. OPG gene polymorphisms 163A/G, 245T/G conformed to the Hardy-Weinberg equilibrium. The statistical differences in genotype of AA, AG, GG at 163A/G locus were founded in RA and controls. The G allele was associated with an increased risk of RA, with OR 1.219 (95% CI: 1.066-2.339). According to the observation, there are no significant differences between the RA and control groups with respect to genotype and allele frequencies of OPG gene 245T/G (χ(2)=0.734, 0.518, p>0.05).. The OPG gene 163A/G SNP may be associated with the susceptibility of RA, G allele may be the risk factor for the development of RA.

Topics: Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid; Case-Control Studies; China; Female; Gene Frequency; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Humans; Male; Middle Aged; Osteoprotegerin; Polymorphism, Single Nucleotide; Risk; Young Adult

We earlier found that TNFα but not interleukin (IL)-17 is indispensable in the pathogenesis of spontaneously occurring rheumatoid arthritis (RA)-like disease in our newly established FcγRIIB-deficient C57BL/6 (B6) mouse model, designated KO1. Here, we examined the role of IL-6 in the pathogenesis of RA features in KO1, with particular reference to cartilage and bone destruction in arthritic joints.. To evaluate the preventive effect of MR16-1, a rat anti-mouse IL-6 receptor (IL-6R) mAb, 4-month-old preclinical KO1 mice were divided into three groups: the first treated with MR16-1 for 6 months, the second treated with normal rat IgG, as a control, and the third left untreated. The incidence and severity of arthritis, immunological abnormalities, and transcription levels of receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), and inflammatory cytokines/chemokines in ankle joint tissues were compared among the three groups. The therapeutic effect of MR16-1 was examined by treating 7-month-old KO1 mice in the early stages of arthritis for 2 months.. Compared with the findings in the KO1 mice left untreated or treated with normal rat IgG, the development of arthritis was markedly suppressed in mice with MR16-1 treatment started from preclinical stages. The suppression was associated with the decrease in production of autoantibodies, rheumatoid factors (RF), and anti-cyclic citrullinated peptide (CCP). Histologically, marked synovitis, pannus formation, and cartilage and bone destruction associated with the increase in tartrate-resistant acid phosphatase (TRAP)-positive osteoclast generation were evident in the two control groups; however, these findings were virtually absent in MR16-1-treated mice. Real-time PCR analysis revealed that the up-regulated expression levels of MCP-1, IL-6, and TNFα, and the aberrantly high RANKL/OPG expression ratio in synovial joint tissues from the two control groups of mice with overt arthritis were significantly suppressed in MR16-1-treated mice. In mice with therapeutic MR16-1 treatment, there was no progression in arthritis score and the RANKL/OPG ratio in joint tissues was significantly suppressed.. Administration of an anti-IL-6R mAb ameliorated spontaneously occurring RA-like disease features, indicating that IL-6, as well as TNFα, plays a pivotal role in the pathogenesis of RA in KO1 mice. Current studies showed that, in addition to the role in enhancing autoantibody production, IL-6 promotes synovial tissue inflammation and osteoclastogenesis, leading to the severe synovitis with pannus formation and the progressive cartilage and bone destruction in multiple joints.

Topics: Animals; Antibodies, Monoclonal; Arthritis, Rheumatoid; Autoantibodies; Cytokines; Disease Models, Animal; Joints; Mice; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, IgG; Receptors, Interleukin-6; Severity of Illness Index

We determined whether osteoprotegerin (OPG) concentrations are associated with established cardiovascular disease (CVD) among patients with rheumatoid arthritis (RA).. OPG concentrations were measured by ELISA in 151 patients with RA (54 with CVD) and 62 age-matched control subjects without CVD. Established CVD was composed of documented ischemic heart disease, cerebrovascular disease, and peripheral artery disease.. In patients with RA, age, body mass index (BMI), rheumatoid factor (RF) positivity, anticyclic citrullinated peptide (anti-CCP) antibody positivity, and joint erosion status were associated with OPG concentrations [partial R (p) = 0.175 (0.03), -0.277 (0.0009), 0.323 (< 0.0001), 0.217 (0.008), and 0.159 (0.05), respectively]. Median (interquartile range) OPG concentrations increased from 6.38 (3.46-9.31) to 7.07 (5.04-10.65) and 8.64 (6.00-11.52) ng/ml in controls and patients with RA who had CVD and those who did not, respectively (p = 0.0002). Upon adjustment for age, sex, traditional risk factors, and BMI in mixed regression models, OPG concentrations remained lower in controls compared to patients with RA without CVD (p = 0.05) and in the latter compared to those with CVD (p = 0.03); the association of OPG concentrations with CVD among patients with RA also persisted after additional adjustment for RF and anti-CCP antibody positivity, and erosion status (p = 0.04).. OPG concentrations are associated with disease severity and CVD prevalence in patients with RA. Whether consideration of OPG concentrations can improve CVD risk stratification in RA merits future longitudinal investigation.

Topics: Aged; Aged, 80 and over; Arthritis, Rheumatoid; Cardiovascular Diseases; Female; Humans; Male; Middle Aged; Osteoprotegerin; Risk Factors; Severity of Illness Index

Patients with rheumatoid arthritis (RA) have accelerated atherosclerosis, but there is limited information about the genetic contribution to atherosclerosis in this population. Therefore, we examined the association between selected genetic polymorphisms and coronary atherosclerosis in patients with RA.. Genotypes for single-nucleotide polymorphisms (SNPs) in 152 candidate genes linked with autoimmune or cardiovascular risk were measured in 140 patients with RA. The association between the presence of coronary artery calcium (CAC) and SNP allele frequency was assessed by logistic regression with adjustment for age, sex, and race. To adjust for multiple comparisons, a false discovery rate (FDR) threshold was set at 20%.. Patients with RA were 54±11 years old and predominantly Caucasian (89%) and female (69%). CAC was present in 70 patients (50%). A variant in rs2073618 that encodes an Asn3Lys missense substitution in the osteoprotegerin gene (OPG, TNFRSF11B) was significantly associated with the presence of CAC (OR=4.09, p<0.00026) and withstands FDR correction.. Our results suggest that a polymorphism of the TNFRSF11B gene, which encodes osteoprotegerin, is associated with the presence of coronary atherosclerosis in patients with RA. Replication of this finding in independent validation cohorts will be of interest.

Topics: Adult; Aged; Arthritis, Rheumatoid; Atherosclerosis; Coronary Artery Disease; Female; Genetic Association Studies; Genetic Predisposition to Disease; Humans; Male; Middle Aged; Osteoprotegerin; Polymorphism, Single Nucleotide; White People

Proinflammatory cytokines and growth factors, which regulate mutual interactions between immune system cells and bone tissue cells, play a major role in the formation of bone changes in rheumatoid arthritis (RA). The aim of the work was to assess serum concentration of osteoprotegerin (OPG), RANKL, Dkk-1 and sclerostin in RA patients compared to a control group and to analyze changes of these concentrations during methotrexate (MTX) therapy. Patients enrolled in the study were 30 women of Caucasian origin aged 30-74 years with RA. Patients with active form of the disease were administered recommended doses of MTX for at least 6 months. The study group was divided into subgroup I-patients with improvement; and subgroup II-patients with no improvement. The control group consisted of 12 healthy women in the age of 41-73. Before MTX therapy, RA patients had higher levels of RANKL (644.97 ± 477.13 vs. 255.19 ± 130.26 pmol/l), lower values of OPG/RANKL (0.01 ± 0.0101 vs. 0.02 ± 0.0078) and higher levels of Dkk-1 protein (1821.32 ± 1060.28 vs. 548.52 ± 36.35 pg/ml) compared to the control group. In the analyzed group of patients (all patients receiving MTX regardless of responder non responder status) after 6 months of therapy, a statistically significant increase in the ratio of OPG/RANKL was found (0.0118 ± 0.0102 vs. 0.0141 ± 0.0118; p = 0.02). The index value of OPG/RANKL differed significantly depending on the resultant effect of treatment (0.01702 ± 0.01274 in the subgroup of improvement vs. 0.00675 ± 0.00289 in the subgroup without improvement). The difference in the mean concentrations of Dkk-1 before and after treatment with MTX between subgroups I and II was statistically significant (p = 0.002). In subgroup I, mean concentration of Dkk-1 decreased after 6 months of treatment with MTX (2054.72 ± 1004.74 vs. 1831.70 ± 851.70 pg/ml); while in subgroup II, the mean concentration of Dkk-1 increased (1214.48 ± 738.32 vs. 2275.01 ± 1385.23 pg/ml). There were no statistically significant changes in the mean concentrations of sclerostin before and after treatment with MTX (in whole group treatment with MTX, in subgroup I, and in subgroup II). The results confirm the presence of disorders of bone metabolism in patients with RA. Treatment with MTX affects the value of the ratio of OPG/RANKL and concentration of Dkk-1.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers, Pharmacological; Bone and Bones; Bone Morphogenetic Proteins; Disease Progression; Female; Genetic Markers; Humans; Intercellular Signaling Peptides and Proteins; Methotrexate; Middle Aged; Osteoprotegerin; RANK Ligand

The aim of this study was to investigate the regulative activity of (5R)-5-hydroxytriptolide (LLDT-8) on receptor activator of nuclear factor κ-B ligand (RANKL)/receptor activator of nuclear factor κ-B (RANK)/Osteoprotegerin (OPG) system in rheumatoid arthritis (RA) and its anti-osteoclastogenesis mechanism.. The expression of OPG, RANK and RANKL in CD3(+) T leukomonocytes in both peripheral blood and synovial fluid of RA patients was evaluated by flow cytometry. The levels of interleukin (IL) 1β, IL-6, IL-10, IL-21 and IL-23 in the supernatants of peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were assayed by ELISA. Tartaric acid phosphatase (TRAP) staining was used to identify the osteoclast-like cells derived from RAW264.7. Western blotting analysis was used to check the downstream molecules of RANKL.. LLDT-8 increased the rate of OPG expression in CD3(+) T leukomonocytes in peripheral blood as well as the ratio of OPG/RANKL in both peripheral blood and synovial fluid. LLDT-8 inhibited IL-1β, IL-6, IL-21 and IL-23 secretion, but promoted the secretion of IL-10 in the supernatants of PBMCs and SFMCs. In addition, LLDT-8 decreased the number of TRAP-positive cells derived from RAW264.7 in the presence of RANKL and M-CSF. Furthermore, LLDT-8 also inhibited the expression of p-IκB, a key regulator of RANKL signaling pathway.. LLDT-8 exerts its anti-osteoclastogenesis effect in RA probably through regulating RANKL/RANK/OPG system and its downstream signaling pathway as well as cytokine productions.

Topics: Adult; Aged; Animals; Arthritis, Rheumatoid; Cell Differentiation; Diterpenes; Drugs, Chinese Herbal; Female; Humans; Interleukin-10; Interleukin-6; Interleukins; Leukocytes, Mononuclear; Macrophage Colony-Stimulating Factor; Male; Membrane Glycoproteins; Mice; Middle Aged; NF-kappa B; Osteoclasts; Osteoprotegerin; Phytotherapy; RANK Ligand; RAW 264.7 Cells; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction

To investigate the correlation of the receptor activator of nuclear factor kappa-B ligand (RANKL)/serum osteoprotegerin (OPG) system, Dickkopf-1 (DKK-1) and bone marrow edema (BME) in rheumatoid arthritis (RA) with the complaint of knee pain.. The clinical data of 50 cases of RA with the complaint of knee pain were collected. According to MRI finding, half of them (25 cases) had bone marrow edema (BME). Each patient received the measurement of serum OPG, RANKL, DKK-1, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), anti cyclic citrullinated peptide antibody (CCP), rheumatoid factort(RF). The clinical symptoms, disease activity score 28 (DAS28), were compared between BME and non-BME griups, and the correlation between RANKL/OPG system, DKK-1 and BME of RA was analyzed.. Compared with non BME group, BME group had shorter course (P=0.000), higher DAS28 score (P=0.009), CRP (P=0:000), RF (P=0.033) and CCP (P=0.012). lower level of serum OPG (P=0.000), higher level of RANKL (P=0.000), RANKL/OPG (P=0.000), and DKK-1 (P=0.001). The severity of bone marrow edema was correlated with the serum RANKL (volume r(s)=0.31, P=0.027; degree r(s)=0.33, P=0.022), RANKL/OPG (volume r(s)=0.29, P=0.039; degree r(s)=0.28, P=0.043), DKK-1 (volume r(s)=0.33, P=0.021; degree r(s)=0.34, P=0.019).. BME is one of the early signs of bone erosion in RA, there were more active inflammation, autoantibodies, and osteocasts in RA patients with BME.

Topics: Arthralgia; Arthritis, Rheumatoid; Autoantibodies; Bone Marrow; C-Reactive Protein; Edema; Humans; Intercellular Signaling Peptides and Proteins; Knee Joint; Osteoprotegerin; RANK Ligand; Rheumatoid Factor

Topics: Aged; Arthritis, Rheumatoid; Autoantibodies; Bone Resorption; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Osteoprotegerin

Bone disease in rheumatoid arthritis (RA) is a complex phenomenon where genetic risk factors have been partially evaluated. The system formed by receptor activator for nuclear factor-κB (RANK), receptor activator for nuclear factor-κB ligand (RANKL), and osteoprotegerin (OPG): RANK/RANKL/OPG is a crucial molecular pathway for coupling between osteoblasts and osteoclasts, since OPG is able to inhibit osteoclast differentiation and activation. We aim to evaluate the association between SNPs C950T (rs2073617), C209T (rs3134069), T245G (rs3134070) in the TNFRSF11B (OPG) gene, and osteoporosis in RA. We included 81 women with RA and 52 healthy subjects in a cross-sectional study, genotyped them, and measured bone mineral density (BMD) at the lumbar spine and the femoral neck. Mean age in RA was 50 ± 12 with disease duration of 12 ± 8 years. According to BMD results, 23 (33.3%) were normal and 46 (66.7%) had osteopenia/osteoporosis. We found a higher prevalence of C allele for C950T SNP in RA. Polymorphisms C209T and T245G did not reach statistical significance in allele distribution. Further studies including patients from other regions of Latin America with a multicenter design to increase the sample size are required to confirm our findings and elucidate if C950T SNP could be associated with osteoporosis in RA.

Topics: Adult; Aged; Alleles; Arthritis, Rheumatoid; Bone Density; Case-Control Studies; Cross-Sectional Studies; Female; Genotype; Humans; Mexico; Middle Aged; Osteoporosis; Osteoprotegerin; Polymorphism, Single Nucleotide; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Risk Factors; Young Adult

In order to investigate the association between osteoprotegerin (OPG) gene polymorphisms and rheumatoid arthritis (RA), we studied OPG rs3102735 T/C and rs2073618 G/C polymorphisms in a Chinese Han population comprising 574 patients with RA and 804 controls. Genotyping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was conducted. Our data indicated that OPG rs3102735 T/C and rs2073618 G/C polymorphisms were not associated with the risk of RA. However, among older patients (≥55 years), patients with the OPG rs3102735 TC (TC vs TT: OR = 0.68, 95%CI = 0.49‑0.96, P = 0.029) and TC/CC (TC+CC vs TT: OR = 0.69, 95%CI = 0.49‑0.96, P = 0.026) genotypes showed a significantly lower risk of RA than patients with the TT genotype, while patients with the OPG rs2073618 GC (GC vs GG: OR = 1.53, 95%CI = 1.13‑2.07, P = 0.006) and GC/CC (GC+CC vs GG: OR = 1.43, 95%CI = 1.07‑1.92, P = 0.015) genotypes showed a significantly higher risk of RA than patients with the GG genotype. We also found a significantly increased risk of RA associated with the OPG rs2073618 GC (GC vs GG: OR = 1.44, 95%CI = 1.07‑1.93, P = 0.018) and GC/CC (GC+CC vs GG: OR = 1.39, 95%CI = 1.04‑1.86, P = 0.024) genotypes among functional class III+IV patients. Our results were obtained from only a moderate-sized sample and, thus, a larger study with a more diverse ethnic population is needed to confirm these results.

Topics: Adult; Aged; Alleles; Arthritis, Rheumatoid; Asian People; Female; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Humans; Male; Middle Aged; Osteoprotegerin; Polymorphism, Single Nucleotide

Polymers of similar molecular weights and chemical constitution but varying in their macromolecular architectures were conjugated to osteoprotegerin (OPG) to determine the effect of polymer topology on protein activity in vitro and in vivo. OPG is a protein that inhibits bone resorption by preventing the formation of mature osteoclasts from the osteoclast precursor cell. Accelerated bone loss disorders, such as osteoporosis, rheumatoid arthritis, and metastatic bone disease, occur as a result of increased osteoclastogenesis, leading to the severe weakening of the bone. OPG has shown promise as a treatment in bone disorders; however, it is rapidly cleared from circulation through rapid liver uptake, and frequent, high doses of the protein are necessary to achieve a therapeutic benefit. We aimed to improve the effectiveness of OPG by creating OPG-polymer bioconjugates, employing reversible addition-fragmentation chain transfer polymerization to create well-defined polymers with branching densities varying from linear, loosely branched to densely branched. Polymers with each of these architectures were conjugated to OPG using a "grafting-to" approach, and the bioconjugates were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The OPG-polymer bioconjugates showed retention of activity in vitro against osteoclasts, and each bioconjugate was shown to be nontoxic. Preliminary in vivo studies further supported the nontoxic characteristics of the bioconjugates, and measurement of the bone mineral density in rats 7 days post-treatment via peripheral quantitative computed tomography suggested a slight increase in bone mineral density after administration of the loosely branched OPG-polymer bioconjugate.

Topics: Animals; Arthritis, Rheumatoid; Bone Density; Bone Resorption; Humans; Osteoclasts; Osteoporosis; Osteoprotegerin; Polymers; Rats

We previously reported that low ratio of osteoprotegerin (OPG) to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was associated with Disease Activity Score in 28 joints (DAS28) remission at 6 months in patients with early rheumatoid arthritis (RA). Here, we aimed to evaluate the value of baseline OPG/TRAIL ratio in predicting clinical and radiological outcomes in patients with early RA in the ESPOIR cohort.. OPG and TRAIL serum concentrations were assessed in the ESPOIR cohort patients. Patients with definite RA were included in this study. Patients were excluded if they had high erosion score at baseline (>90(th) percentile) or received biological therapy during the first 2 years of follow-up. Data were analyzed by univariate analysis and multivariate logistic regression to predict 1-year DAS28 remission and 2-year radiographic disease progression.. On univariate analysis of 399 patients, OPG/TRAIL ratio at baseline was significantly lower in patients with than without remission at 1 year (p = 0.015). On multivariate logistic regression including age, gender, body mass index and DAS28, low OPG/TRAIL ratio was independently associated with remission at 1 year (odds ratio 1.68 [95 % confidence interval 1.01-2.79]). On univariate analysis, high OPG/TRAIL ratio at baseline was associated with rapid progression of erosion at 2 years (p = 0.041), and on multivariate logistic regression including age, anti-citrullinated protein antibody positivity and C-reactive protein level, OPG/TRAIL ratio independently predicted rapid progression of erosion at 2 years.. OPG/TRAIL ratio at baseline was an independent predictor of 1-year remission and 2-year rapid progression of erosion for patients with early rheumatoid arthritis. Thus, OPG/TRAIL ratio could be included in matrix prediction scores to predict rapid radiographic progression. Further confirmation in an independent cohort is warranted.

Topics: Adult; Arthritis, Rheumatoid; Biomarkers; Cohort Studies; Female; Humans; Male; Middle Aged; Osteoprotegerin; Prognosis; Prospective Studies; TNF-Related Apoptosis-Inducing Ligand

We designed OP3-4 (YCEIEFCYLIR), a cyclic peptide, to mimic the soluble osteoprotegerin (OPG), and was proven to bind to RANKL (receptor activator of NF-κB ligand), thereby inhibiting osteoclastogenesis. We recently found that another RANKL binding peptide, W9, could accelerate bone formation by affecting RANKL signaling in osteoblasts. We herein demonstrate the effects of OP3-4 on bone formation and bone loss in a murine model of rheumatoid arthritis.. Twenty-four seven-week-old male DBA/1J mice were used to generate a murine model of collagen-induced arthritis (CIA). Then, vehicle or OP3-4 (9 mg/kg/day or 18 mg/kg/day) was subcutaneously infused using infusion pumps for three weeks beginning seven days after the second immunization. The arthritis score was assessed, and the mice were sacrificed on day 49. Thereafter, radiographic, histological and biochemical analyses were performed.. The OP3-4 treatment did not significantly inhibit the CIA-induced arthritis, but limited bone loss. Micro-CT images and quantitative measurements of the bone mineral density revealed that 18 mg/kg/day OP3-4 prevented the CIA-induced bone loss at both articular and periarticular sites of tibiae. As expected, OP3-4 significantly reduced the CIA-induced serum CTX levels, a marker of bone resorption. Interestingly, the bone histomorphometric analyses using undecalcified sections showed that OP3-4 prevented the CIA-induced reduction of bone formation-related parameters at the periarticular sites.. The peptide that mimicked OPG prevented inflammatory bone loss by inhibiting bone resorption and stimulating bone formation. It could therefore be a useful template for the development of small molecule drugs for inflammatory bone loss.

Topics: Amino Acid Sequence; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Density; Bone Resorption; Cartilage, Articular; Cell Differentiation; Cells, Cultured; Collagen Type I; Enzyme-Linked Immunosorbent Assay; Infusions, Subcutaneous; Male; Mice, Inbred DBA; Oligopeptides; Osteoblasts; Osteoclasts; Osteogenesis; Osteoprotegerin; Peptides; Protein Binding; RANK Ligand; Tibia; X-Ray Microtomography

Anemone flaccida Fr. Schmidt is used in the clinical compound prescription for the treatment of rheumatoid arthritis (RA) in China and has the traditional use of draining dampness, diminishing swelling, and relieving pain. Total saponins (TS) are the characteristic components and also the main active ingredients of A. flaccida. Previous reports indicated that TS possess anti-inflammatory and immunoregulatory properties; however, the effects of TS on bone destruction of RA have not been evaluated. In this study, our data first showed the therapeutic effects of TS on severity of arthritis and arthritis progression in collagen-induced arthritis (CIA) rats. Then, by microfocal computed tomography (CT) quantification, TS significantly increased bone mineral density, bone volume fraction, and trabecular thickness and decreased trabecular separation of inflamed joints both at peri-articular and extra-articular locations. TS also diminished the level of the bone resorption marker CTX-I and simultaneously increased the bone formation marker osteocalcin in sera of CIA rats. Interestingly, TS prevented bone destruction by reducing the number of osteoclasts in inflamed joints, reducing the expression of receptor activator of nuclear factor-κF (RANK) ligand (RANKL) and RANK, increasing the expression of osteoprotegerin (OPG), at both mRNA and protein levels, and decreasing the ratio of RANKL to OPG in inflamed joints and sera of CIA rats. This was further confirmed in the co-culture system of human fibroblast-like synovial and peripheral blood mononuclear cells. In addition, TS inhibited the levels of pro-inflammatory cytokines implicated in bone resorption, such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNFα), IL-6, IL-17, and IL-23 in sera and joints. These findings offer convincing evidence that TS attenuate RA partially by preventing both focal bone destruction and systemic bone loss. This anti-erosive effect results in part from inhibiting osteoclastogenesis by regulating the RANKL/RANK/OPG signaling pathway. The suppression of systemic and local pro-osteoclastogenic cytokines by TS was also highly effective.

Topics: Anemone; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone and Bones; Bone Resorption; Coculture Techniques; Cytokines; Disease Progression; Fibroblasts; Humans; Inflammation Mediators; Joints; Leukocytes, Mononuclear; Male; Osteoclasts; Osteogenesis; Osteoprotegerin; RANK Ligand; Rats, Sprague-Dawley; Saponins; Severity of Illness Index; Signal Transduction

Rheumatoid arthritis is a systemic autoimmune disease characterized by joint erosions, progressive focal bone loss, and chronic inflammation.. 20 female patients with moderate-to-severe rheumatoid arthritis were treated with anti-TNF-antibody adalimumab in addition to concomitant antirheumatic therapies. Patients were assessed for overall disease activity using the DAS28 score, and neopterin, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) concentrations as well as osteoprotegerin (OPG) and soluble receptor activator of NF-κB ligand (sRANKL) concentrations were determined before therapy and at week 12. Neopterin as well as OPG and sRANKL were determined by commercial ELISAs.. Before anti-TNF therapy patients presented with high disease activity and elevated concentrations of circulating inflammatory markers. OPG concentrations correlated with neopterin (rs = 0.494, p = 0.027), but not with DAS28. OPG concentrations and disease activity scores declined during anti-TNF-treatment (both p < 0.02). Patients who achieved remission (n = 7) or showed a good response according to EULAR criteria (n = 13) presented with initially higher baseline OPG levels, which subsequently decreased significantly during treatment (p = 0.018 for remission, p = 0.011 for good response).. Adalimumab therapy was effective in modifying disease activity and reducing proinflammatory and bone remodelling cascades.

Topics: Adalimumab; Adult; Antirheumatic Agents; Arthritis, Rheumatoid; Drug Therapy, Combination; Female; Humans; Middle Aged; Neopterin; Osteoprotegerin; RANK Ligand

Osteoprotegerin (OPG) may contribute to the link between systemic inflammation and increased cardiovascular risk. We investigated the relationship of OPG concentrations with endothelial activation and carotid atherosclerosis in rheumatoid arthritis (RA).. OPG concentrations and those of endothelial activation molecules were measured by using ELISA in 34 patients who were treated with infliximab (IFX), both immediately before and after an IFX infusion. Carotid intima-media thickness (CIMT) and plaque were determined by ultrasound in 27 of the study participants.. Median (interquartile range) OPG concentrations decreased from 4.8 pmol/l (2.8-6.5) to 4.4 pmol/l (2.9-6.1; p = 0.04) upon IFX infusion. Baseline OPG concentrations were inversely associated with those of total and low-density lipoprotein (LDL) cholesterol (partial R = -0.50, p = 0.004, and R = -0.48, p = 0.007, respectively). Prior to IFX administration, OPG concentrations were associated with those of intercellular adhesion molecule (ICAM)-1 (partial R = 0.34, p = 0.05), CIMT (partial R = 0.51 to 0.52, p < 0.009), and plaque (OR = 1.52, 95% CI 1.01-2.29 to OR = 1.61, 95% CI 1.03-2.51; p < 0.04), independent of conventional risk factors and C-reactive protein concentrations or disease activity. Except for the OPG concentrations-plaque association (p = 0.09), these relationships remained significant subsequent to IFX administration (p < 0.05). Reductions in OPG levels related to those in vascular cell adhesion molecule (VCAM)-1 concentrations (partial R = 0.35, p = 0.04) and had borderline significance (p = 0.09) with those in ICAM-1 (partial R = 0.29) concentrations.. OPG concentrations are independently associated with endothelial activation and carotid atherosclerosis in RA. Reductions in OPG concentrations upon IFX administration are associated with decreased endothelial activation. OPG may be involved in increased cardiovascular disease risk and may improve its stratification in patients with RA.

Topics: Aged; Arthritis, Rheumatoid; Atherosclerosis; Carotid Artery Diseases; Endothelium, Vascular; Female; Humans; Male; Middle Aged; Osteoprotegerin

to analyze the correlation between Receptor activator of nuclear factor-κβ ligand (RANKL), Osteoprotegrin (OPG) serum level with cartilage oligomeric matrix protein (COMP) serum level as a marker of cartilage degradation in rheumatoid arthritis patients.. a cross-sectional study was conducted on the subjects who came to the outpatient clinic of rheumatology in Cipto Mangunkusumo Hospital. Patients were diagnosed based on the American College of Rheumatology (ACR) 1987 revised criteria. All numerical data, both primary data and data transformation were not normally distributed, so we did bivariate analysis with Spearman correlation test.. we collected the data of 60 RA patients with majority of the subject had active disease activity (78.3%). Methotrexate was the most widely disease modifying anti-rheumatoid drug (DMARD) used, either as a single drug (51.7%) or in combination with another DMARD (25.1%). Bivariate analysis was revealed that RANKL, OPG, and OPG/RANKL serum level have no significantly correlation with COMP serum level (p=0.52; p=0.25; p=0.2, respectively).. RANKL and OPG serum level, had no correlation with cartilage degradation in rheumatoid arthritis patients.

Topics: Adolescent; Adult; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Cartilage; Cartilage Oligomeric Matrix Protein; Cross-Sectional Studies; Female; Humans; Methotrexate; Middle Aged; Osteoprotegerin; RANK Ligand; Young Adult

To identify how the gp130-signaling cytokine oncostatin M (OSM), acting alone or in concert with IL-1β or TNFα, affects synovial fibroblast expression of genes relevant to inflammation and bone erosion in inflammatory arthritis.. Synovial fibroblasts (SFs) were isolated from non-arthritic wild type (WT) or OSM receptor deficient (OSMR(-/-)) mice and stimulated with OSM, IL-1β or TNFα and their combinations. Cytokine gene expression was assessed by quantitative RT-PCR. ELISA, flow cytometry and immunohistochemistry identified protein expression. Gene expression patterns were confirmed in SFs isolated from patients with osteoarthritis (OASFs) and rheumatoid arthritis (RASFs).. Expression of OSM and its receptors, gp130, OSMR and LIFR, was increased in synovial tissue from the mouse antigen-induced arthritis model. In isolated WT mouse synovial fibroblasts OSM alone, or in synergy with IL-1β, or together with TNFα, potently induced expression of the pro-inflammatory cytokine IL-6. OSM also induced a sustained increase in mRNA levels of the pro-osteoclastic cytokine RANKL. Combining OSM with IL-1β, but not with TNFα, further increased RANKL expression. Importantly these effects of OSM were all dependent on the expression of OSMR. Furthermore, OSM also increased expression of its own receptors, gp130 and OSMR and the IL-1 receptor, IL1-R1; the latter effects were also observed in both human OASFs and RASFs.. Together our data suggests that OSM signaling via OSMR in SFs has the potential to contribute significantly to joint destruction in inflammatory arthritis. It not only induces expression of pro-inflammatory and pro-osteoclastic cytokines but can also augment its own actions and that of IL-1 by inducing expression of OSMR and IL-1R1.

Topics: Animals; Arthritis, Rheumatoid; Fibroblasts; Gene Expression Regulation; Humans; Interleukin-1beta; Mice, Inbred C57BL; Oncostatin M; Osteoprotegerin; RANK Ligand; Receptors, Interleukin-1; Receptors, Oncostatin M; RNA, Messenger; Synovial Membrane; Tumor Necrosis Factor-alpha

To estimate endothelial dysfunction in patients with rheumatoid arthritis (RA) of short duration in relation to disease activity based on the assessment of 28 joints (DAS28).. We studied 29 patients (22 women, mean age 41 (SD, 9) years) with RA of short duration and 29 healthy controls. The RA subjects were divided into those with low (DAS28: 2.6-5.1, n = 18) or high (DAS28 > 5.1, n = 11) disease activity. Exclusion criteria included clinically overt atherosclerosis and other coexistent diseases. Biochemical markers of inflammatory activation and endothelial dysfunction were measured.. There were no significant intergroup differences in the majority of classical cardiovascular risk factors. High-sensitivity C-reactive protein, tumor necrosis factor- α , and interleukin-6 were increased in RA subjects. Compared to the controls, levels of soluble vascular cell adhesion molecule-1, von Willebrand factor, and pentraxin-3 were significantly elevated in RA subjects with low disease activity, exhibiting no further significant rises in those with high disease activity. Asymmetric dimethyl-L-arginine, soluble E-selectin, monocyte chemotactic protein-1, and osteoprotegerin were increased only in RA patients with high disease activity.. Our findings might suggest a dissociation of pathways governing generalized and joint-specific inflammatory reactions from those involved in endothelial activation and inflammation within the vascular wall.

Topics: Adult; Arginine; Arthritis, Rheumatoid; Biomarkers; C-Reactive Protein; E-Selectin; Female; Humans; Interleukin-6; Male; Middle Aged; Osteoprotegerin; Risk Factors; Serum Amyloid P-Component; Vascular Cell Adhesion Molecule-1; von Willebrand Factor

Progression of joint destruction in rheumatoid arthritis (RA) is partly heritably; 45 to 58% of the variance in joint destruction is estimated to be explained by genetic factors. The binding of RANKL (Receptor Activator for Nuclear Factor κ B Ligand) to RANK results in the activation of TRAF6 (tumor necrosis factor (TNF) receptor associated factor-6), and osteoclast formation ultimately leading to enhanced bone resorption. This bone resorption is inhibited by osteoprotegerin (OPG) which prevents RANKL-RANK interactions. The OPG/RANK/RANKL/TRAF6 pathway plays an important role in bone remodeling. Therefore, we investigated whether genetic variants in OPG, RANK, RANKL and TRAF6 are associated with the rate of joint destruction in RA.. 1,418 patients with 4,885 X-rays of hands and feet derived from four independent data-sets were studied. In each data-set the relative increase of the progression rate per year in the presence of a genotype was assessed. First, explorative analyses were performed on 600 RA-patients from Leiden. 109 SNPs, tagging OPG, RANK, RANKL and TRAF6, were tested. Single nucleotide polymorphisms (SNPs) significantly associated in phase-1 were genotyped in data-sets from Groningen (Netherlands), Sheffield (United Kingdom) and Lund (Switzerland). Data were summarized in an inverse weighted variance meta-analysis. Bonferonni correction for multiple testing was applied.. We found that 33 SNPs were significantly associated with the rate of joint destruction in phase-1. In phase-2, six SNPs in OPG and four SNPs in RANK were associated with progression of joint destruction with P-value <0.05. In the meta-analyses of all four data-sets, RA-patients with the minor allele of OPG-rs1485305 expressed higher rates of joint destruction compared to patients without these risk variants (P = 2.35x10-4). This variant was also significant after Bonferroni correction.. These results indicate that a genetic variant in OPG is associated with a more severe rate of joint destruction in RA.

Topics: Adult; Aged; Arthritis, Rheumatoid; Disease Progression; Female; Gene Frequency; Genetic Predisposition to Disease; Genotype; Haplotypes; Humans; Joint Diseases; Male; Meta-Analysis as Topic; Middle Aged; Osteoprotegerin; Polymorphism, Single Nucleotide; Radiography; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Risk Factors; TNF Receptor-Associated Factor 6

Patients with rheumatoid arthritis (RA) have a higher prevalence of osteoporosis and hip fracture than healthy individuals. Multiple genetic loci for osteoporotic fracture were identified in recent genome-wide association studies. The purpose of this study was to identify genetic variants associated with the occurrence of hip fracture in Japanese patients with RA.. DNA samples from 2,282 Japanese patients with RA were obtained from the DNA collection of the Institute of Rheumatology Rheumatoid Arthritis cohort (IORRA) study. Six single nucleotide polymorphisms (SNPs) that have been reported to be associated with fractures in recent studies were selected and genotyped. Forty hip fractures were identified with a maximum follow-up of 10 years. The genetic risk for hip fracture was examined using a multivariate Cox proportional hazards regression model.. The risk analyses revealed that patients who are homozygous for the major allele of SNP rs6993813, in the OPG locus, have a higher risk for hip fracture (hazard ratio [95% CI] = 2.53 [1.29-4.95], P = 0.0067). No association was found for the other SNPs.. Our results indicate that an OPG allele is associated with increased risk for hip fracture in Japanese patients with RA.

Topics: Aged; Arthritis, Rheumatoid; Asian People; Cohort Studies; Female; Genome-Wide Association Study; Hip Fractures; Humans; Japan; Male; Middle Aged; Osteoprotegerin; Polymorphism, Single Nucleotide; Proportional Hazards Models; Risk

Rheumatoid arthritis is an inflammatory disease with high incidence of cardiovascular disease due to accelerated atherosclerosis. Osteoprotegerin (OPG) has been associated with increased risk of atherosclerotic disease in the general population. Several polymorphisms in the OPG gene with functional effects on cardiovascular disease in non-rheumatic individuals have been described. Therefore, we aimed to analyze the effect of three of these functional OPG polymorphisms on the risk of cardiovascular disease in a large and well-characterized cohort of Spanish patients with rheumatoid arthritis.. Three OPG gene variants (rs3134063, rs2073618 and rs3134069) were genotyped by TaqMan assays in 2027 Spanish patients with rheumatoid arthritis. Anti-cyclic citrullinated peptide (anti-CCP) antibody testing was positive in 997 of 1714 tested. Also, 18.3% of the whole series had experienced cardiovascular events, including 5.4% with cerebrovascular accidents. The relationship between OPG variants and cardiovascular events was assessed using Cox regression.. No association between OPG gene variants and cardiovascular disease was observed in the whole group of rheumatoid arthritis patients or in anti-CCP positive patients. Nevertheless, a protective effect of CGA haplotype on the risk of cardiovascular disease in general, and specifically in the risk of cerebrovascular complications after adjusting for sex, age at disease diagnosis and traditional cardiovascular risk factors was disclosed in anti-CCP negative patients (HR = 0.54; 95%CI: 0.31-0.95; p = 0.032 and HR = 0.17; 95%CI: 0.04-0.78; p = 0.022, respectively).. Our results indicate a protective effect of the OPG CGA haplotype on cardiovascular risk, mainly due to a protective effect against cerebrovascular events in anti-CCP negative rheumatoid arthritis patients.

Topics: Adult; Aged; Arthritis, Rheumatoid; Autoantibodies; Cerebrovascular Disorders; Female; Haplotypes; Humans; Male; Middle Aged; Osteoprotegerin; Peptides, Cyclic; Polymorphism, Single Nucleotide; Spain

To study effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on RANKL signaling pathway and pathway-associated cytokines in patients with rheumatoid arthritis (RA).. Receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), IFN- γ , IL-6, TNF- α , IL-17, and IL-4 were examined in 54 patients with incipient RA using a cytometric bead array (CBA) or an enzyme-linked immunosorbent assay (ELISA).. After 72 hours of incubation of peripheral blood mononuclear cells (PBMCs) with 1,25(OH)2D3 in RA patients, the levels of RANKL, TNF- α , IL-17 and IL-6 significantly decreased compared to those of the control. 1,25(OH)2D3 had no significantly impact on the levels of OPG, RANKL/OPG, and IL-4.. The present study demonstrated that 1,25(OH)2D3 reduced the production of RANKL and the secretion of TNF- α , IL-17, and IL-6 in PBMCs of RA patients, which indicated that 1,25(OH)2D3 might be able to decrease damage of cartilage and bone in RA patients by regulating the expression of RANKL signaling pathway and pathway-associated cytokines.

Topics: Adult; Aged; Arthritis, Rheumatoid; Bone and Bones; Calcitriol; Cartilage; Female; Gene Expression Regulation; Humans; Interleukin-17; Interleukin-4; Interleukin-6; Leukocytes, Mononuclear; Male; Middle Aged; Osteoprotegerin; RANK Ligand; Signal Transduction; Tumor Necrosis Factor-alpha

Leukocyte-associated immunoglobulin-like receptor-1 is an inhibitory receptor primarily expressed by immune cells. This study was undertaken to define the role of this molecule in osteoclast differentiation and rheumatoid arthritis.. In vitro osteoclast assays were performed to characterize the role of Leukocyte-associated immunoglobulin-like receptor-1 in murine and human osteoclastogenesis. Human Leukocyte-associated immunoglobulin-like receptor-1 expression was assessed by immunohistochemistry staining in the synovium of patients with rheumatoid arthritis. The levels of soluble Human Leukocyte-associated immunoglobulin-like receptor-1 were determined by enzyme-linked immunosorbent assay.. We found that multinucleated osteoclast formation from mouse bone marrow cells was inhibited by treatment with a monoclonal antibody against mouse Leukocyte-associated immunoglobulin-like receptor-1 in vitro. By immunohistochemistry, we found that Leukocyte-associated immunoglobulin-like receptor-1 was mainly expressed by macrophages in the inflamed synovial tissue of rheumatoid arthritis patients. In addition, serum and synovial fluid levels of soluble Leukocyte-associated immunoglobulin-like receptor-1 were higher in rheumatoid arthritis patients compared to healthy controls or osteoarthritis patients. Moreover, overexpression of Leukocyte-associated immunoglobulin-like receptor-1 in CD14+ monocytes from healthy volunteers also inhibited human osteoclastogenesis.. Collectively, these data demonstrate for the first time that Leukocyte-associated immunoglobulin-like receptor-1 inhibits osteoclastogenesis. Therefore, these results may have therapeutic implications for the treatment of rheumatoid arthritis.

Topics: Adult; Aged; Animals; Arthritis, Rheumatoid; Bone Marrow Cells; Cell Differentiation; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; Humans; Immunohistochemistry; Lipopolysaccharide Receptors; Male; Mice; Middle Aged; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptors, Immunologic; Synovial Membrane

Total glucosides of paeony (TGP) is a biologically active compound extracted from Paeony root. TGP has been used in rheumatoid arthritis therapy for many years. However, the mechanism by which TGP prevents bone loss has been less explored.. TGP was orally administered for 3 months to New Zealand rabbits with antigen-induced arthritis (AIA). Digital x-ray knee images and bone mineral density (BMD) measurements of the subchondral knee bone were performed before sacrifice. Chondrocytes were observed using transmission electron microscopy (TEM). Histological analysis and mRNA expression of receptor activator of nuclear factor-B ligand (RANKL) and osteoprotegerin (OPG) were evaluated in joint tissues.. The BMD value in TGP rabbits was significantly higher compared with that seen in the AIA model rabbits. In addition, the subchondral bone plate was almost completely preserved by TGP treatment, while there was a decrease in bone plate integrity in AIA rabbits. There was less damage to the chondrocytes of the TGP treated group. Immunohistochemical examination of the TGP group showed that a higher percentage of TGP treated chondrocytes expressed OPG as compared to the chondrocytes isolated from AIA treated animals. In contrast, RANKL expression was significantly decreased in the TGP treated group compared to the AIA group. In support of the immunohistochemistry data, the expression of RANKL mRNA was decreased and OPG mRNA expression was enhanced in the TGP group when compared to that of the AIA model group.. These results reveal that TGP suppresses juxta-articular osteoporosis and prevents subchondral bone loss. The decreased RANKL and increased OPG expression seen in TGP treated animals could explain how administration of TGP maintains higher BMD.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Density; Bone Resorption; Chondrocytes; Glucosides; Knee Joint; Osteoporosis; Osteoprotegerin; Paeonia; Phytotherapy; Plant Extracts; Plant Roots; Rabbits; RANK Ligand; RNA, Messenger

Receptor activator of nuclear factor κ B ligand (RANKL) plays a crucial role in the bone erosion of rheumatoid arthritis (RA) by prompting osteoclastogenesis. Considering that 1,25(OH)2D3 has been suggested as a potent inducer of RANKL expression, it should clarify whether vitamin D supplement could result in RANKL overexpression and thereby facilitate excessive osteoclastogenesis and bone resorption in RA. Here, we investigated modulatory effect of 1,25(OH)2D3 on the expression of RANKL and its decoy receptor osteoprotegerin (OPG) in an inflammatory condition of human rheumatoid synoviocyte MH7A. MH7A cells were stimulated with IL1 β and then treated with different concentrations of 1,25(OH)2D3 for 48 h. A significantly elevated OPG/RANKL ratio and markedly decreased levels of IL-6 and TNF β mRNA expression in cells and IL-6 protein in supernatants were observed in IL1 β -induced MH7A in the presence of 1,25(OH)2D3 compared with those in the absence of it. Osteoclast formation was obviously decreased when RAW264.7 cells were treated with both 1,25(OH)2D3 and IL1 β . In summary, although it has a biological function to induce RANKL expression, 1,25(OH)2D3 could upregulate OPG/RANKL ratio and mediate anti-inflammatory action in an inflammatory milieu of synoviocyte, contributing to the inhibition of inflammation-induced osteoclastogenesis in RA.

Topics: Animals; Arthritis, Rheumatoid; Bone Resorption; Cell Line; Dose-Response Relationship, Drug; Fibroblasts; Gene Expression Regulation; Humans; Interleukin-1beta; Interleukin-6; Mice; Osteoclasts; Osteoprotegerin; RANK Ligand; Synovial Membrane; Tumor Necrosis Factor-alpha; Vitamin D

Osteoprotegerin (OPG), a regulator of bone resorption, is involved in the pathogenesis of rheumatoid arthritis (RA) and atherosclerosis. OPG is elevated in patients with coronary artery disease, and high OPG levels are associated with cardiac disease severity and mortality in the general population. The purpose of this study was to investigate the relationship of serum OPG levels, traditional coronary risk factors, and RA-related factors to carotid atherosclerosis in RA patients.. Ninety-one RA patients were studied (85 % women, age 60 ± 10 years). Serum OPG levels were measured by an enzyme-linked immunosorbent assay. The prevalence of carotid plaque was assessed by ultrasonographic imaging in all patients. The relationship between various clinical characteristics, OPG, and carotid plaque was examined.. Serum OPG levels were significantly higher in patients with carotid plaque than in those without plaque (median level 1,397 vs. 887 pg/mL, respectively; P = 0.006). There were no significant differences between RA patients with and without carotid plaque with respect to sex, duration of RA, blood pressure, body mass index, smoking, low-density lipoprotein cholesterol, Disease Activity Score-28, van der Heijde-modified Sharp score, and prednisolone dose. After adjusting for age, sex, and C-reactive protein, elevated levels of OPG were still associated with a higher prevalence of carotid plaque in patients with RA (P = 0.038).. RA patients suffer from accelerated atherosclerosis and also have increased levels of OPG. The serum OPG level is independently associated with carotid plaque.

Topics: Adult; Aged; Arthritis, Rheumatoid; Atherosclerosis; Carotid Artery Diseases; Female; Humans; Male; Middle Aged; Osteoprotegerin; Plaque, Atherosclerotic; Risk Factors; Ultrasonography

Recent data have demonstrated the importance of IL-18 in the induction and perpetuation of chronic inflammation in experimental arthritis. The aim of the present study was to elucidate whether IL-18 has any indirect effects on osteoclastogenesis by regulating the production of molecules from fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA). Human FLS were isolated from RA synovial tissue and cultured in vitro for three to five passages. The expression of IL-18 receptor was determined by RT-PCR. The levels of soluble receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), macrophage colony-stimulating factor (M-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in culture supernatants were determined by ELISA. Membrane-bound RANKL expression was analyzed by flow cytometry. Both α and β chains of IL-18 receptor were confirmed in cultured FLS. IL-18 upregulated membrane-bound RANKL expression and soluble RANKL production by FLS in both time- and dose-dependent manners. In addition, IL-18 enhanced production of M-CSF, GM-CSF, and OPG from cultured FLS in a dose-dependent manner. IL-18 also increased the ratio of RANKL/OPG, suggesting that the net effect of IL-18 on FLS favors for the induction of osteoclast formation and bone resorption. In conclusion, IL-18 upregulates the production of key regulators of osteoclastogenesis from FLS in RA.

Topics: Arthritis, Rheumatoid; Bone Resorption; Cells, Cultured; Female; Gene Expression; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Inflammation; Interleukin-18; Interleukin-18 Receptor alpha Subunit; Interleukin-18 Receptor beta Subunit; Macrophage Colony-Stimulating Factor; Middle Aged; Osteoclasts; Osteogenesis; Osteoprotegerin; RANK Ligand; Synovial Membrane; Up-Regulation

The aim was to further characterize the SKG model of rheumatoid arthritis (RA) and its potential for studying intervention treatments, with special focus on bone targeting therapies. Three individual studies were conducted, using a total of 71 SKG mice, comparing arthritis induction with mannan versus zymosan A, female versus male mice, and the effect of dexamethasone intervention treatment initiated at different time points after arthritis induction. Hind paws were embedded undecalcified in methyl methacrylate, and sections were stained with Masson-Goldner trichrome. Areal Bone Mineral Density (aBMD) of the femora was determined with pDXA. RNA was extracted from the hind paws followed by the quantification by reverse transcriptase PCR. SKG mice stimulated with mannan presented a higher arthritis score than mice stimulated with zymosan A. Female SKG mice developed a more severe arthritis than male SKG mice. Dexamethasone inhibited arthritis clinically as well as histologically when the treatment was initiated prophylactically or within the first week of arthritis. Femoral aBMD was lower in animals with arthritis than in control animals. The RANKL RNA expression was elevated in arthritic mice, whereas OPG RNA expression was unchanged. The results suggest mannan as arthritis inductor and female instead of male mice in experiments as well as an optimal time window for the initiation of treatment. Systemic bone loss as well as local up regulation of RANKL was present early in SKG arthritis. These results demonstrate that SKG arthritis is a suitable new model for evaluating therapies in RA.

Topics: Absorptiometry, Photon; Animals; Antirheumatic Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Biomechanical Phenomena; Bone and Bones; Bone Density; Bone Remodeling; Dexamethasone; Female; Gene Expression Regulation; Male; Mannans; Mice; Mice, Inbred BALB C; Mice, Mutant Strains; Osteoprotegerin; Point Mutation; RANK Ligand; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Severity of Illness Index; Time Factors; ZAP-70 Protein-Tyrosine Kinase; Zymosan

1α,25-Dihydroxyvitamin D3 upregulates the expression of the receptor activator of nuclear factor kB ligand (RANKL), and downregulates osteoprotegerin (OPG) expression. We tested the effects of polymorphisms in the vitamin D receptor gene (VDR), and OPG gene in rheumatoid arthritis (RA) patients and healthy controls and their relationship to bone mineral density (BMD) and development of osteoporosis. Three hundred and fifty women were evaluated, 200 women having RA and 150 healthy control. The subjects were genotyped for polymorphism at BsmI in VDR and A163G in OPG genes by polymerase chain reaction followed by restriction fragment length polymorphism analysis. BMD was also measured. In A163G, the G allele increased the risk for RA and for the development of osteoporosis. We found a significant association between lower hip (BMD-h) and genotype variants of VDR (BsmI) and OPG A163G in RA patients with osteoporosis. Our results suggested that OPG A163G polymorphism was associated with RA susceptibility and with the development of osteoporosis in these patients. Also, VDR and OPG genes are important candidates for osteoporosis in RA patients.

Topics: Adult; Alleles; Arthritis, Rheumatoid; Bone Density; Case-Control Studies; Egypt; Female; Genotype; Humans; Middle Aged; Osteoporosis; Osteoprotegerin; Polymorphism, Genetic; Receptors, Calcitriol

This study is performed to evaluate gingival crevicular fluid (GCF) and serum levels of soluble receptor activator of nuclear factor-κB ligand (sRANKL), interleukin (IL)-17A, IL-17E, IL-17F, IL-17A/F, and osteoprotegerin (OPG) in women with rheumatoid arthritis (RA), osteoporosis (OPR), and those who are systemically healthy (SH), all with periodontal disease.. GCF and serum samples were obtained before any periodontal intervention from 17 women with RA, 19 with OPR, and 13 who were SH with periodontitis. Full-mouth clinical periodontal measurements were recorded. sRANKL, OPG, and IL-17 levels were determined by enzyme-linked immunosorbent assay.. Clinical periodontal measurements were similar in the three study groups. Although the total amounts of GCF albumin, OPG, IL-17A, and IL-17A/F were similar in the study groups, there were statistically significant differences in GCF concentrations of sRANKL, OPG, IL-17A, IL-17E, IL-17F, and IL-17A/F. The sRANKL/OPG ratios were significantly higher in the RA group than in the OPR and SH groups (P <0.05). Serum sRANKL, sRANKL/OPG, and IL-17A/IL-17E ratios were significantly higher, whereas OPG concentrations were significantly lower in the RA group compared to other groups (P <0.05). Serum IL-17A concentrations were significantly higher in the RA and OPR groups than in the SH group (P <0.05).. Increased inflammatory mediator levels in patients with RA, despite the long-term use of various anti-inflammatory drugs, suggest that these patients may have a propensity to overproduce these inflammatory mediators.

Topics: Adult; Aged; Albumins; Arthritis, Rheumatoid; Female; Gingival Crevicular Fluid; Humans; Inflammation Mediators; Interleukin-17; Male; Middle Aged; Osteoporosis; Osteoprotegerin; Periodontal Attachment Loss; Periodontal Index; Periodontal Pocket; Periodontitis; RANK Ligand

Peptides designed from osteoprotegerin (OPG) have previously been shown to inhibit receptor activator of NF-κB ligand (RANKL) and prevent bone loss without significantly inhibiting inflammation. The objective of this study was to develop a novel peptide with dual inhibitory activity against bone loss and inflammation using site-directed mutagenesis. Out of the three putative sites (i.e., Tyr70-Asp78, Tyr82-Glu96, and Leu113-Arg122) available on OPG for RANKL binding, Leu113-Arg122 was used as a template for peptide synthesis. Peptide mutants of the template sequence (112YLEIEFCLKHR122) were synthesized and initially screened for their inhibitory effect on RANK-RANKL binding by competitive ELISA. The most active peptide was further evaluated in vitro for RANKL induced osteoclastogenesis in mouse macrophage cells, and in vivo for Freund's complete adjuvant induced arthritis (AIA) in Lewis rats. The efficacy of the candidate peptide was compared with that of the standard drug celecoxib. The peptide YR-11 (YLEIEFSLKHR), obtained by direct substitution of cysteine with a serine residue in the template sequence, significantly (p<0.05) inhibited RANK-RANKL binding, and RANKL induced TRAP activity and formation of multinucleated osteoclasts without any cytotoxicity. Administration of YR-11 peptide at the dose of 30mg/kg (i.p.) ameliorated both bone loss and inflammation in AIA rats. To elucidate the mechanism for inhibition of inflammation in arthritic rats, serum and tissue cytokines (TNF-α, IL-1β, and IL-6) were analyzed by ELISA and RT-PCR methods. Results confirmed that YR-11 peptide inhibited pro-inflammatory cytokines in the sera and hind paw tissues of AIA rats through its suppressive effect on RANKL induced nuclear translocation of NF-κB. The results obtained in this study substantiate the therapeutic benefit of this novel peptide in the prevention of bone loss and inflammation in rheumatoid arthritis with reduced side effects.

Topics: Amino Acid Sequence; Amino Acid Substitution; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Cell Line; Cell Proliferation; Cytokines; Down-Regulation; Fibroblasts; Male; Mice; Molecular Targeted Therapy; Mutagenesis, Site-Directed; NF-kappa B; Osteoclasts; Osteoprotegerin; Peptide Fragments; Protein Binding; RANK Ligand; Rats; Rats, Sprague-Dawley; Receptor Activator of Nuclear Factor-kappa B; RNA, Messenger; Synovial Membrane

The objective of this study is to investigate the relationship between soluble components of the interleukin 6 (IL-6) system mediating and modifying IL-6 trans-signaling and the RANKL-RANK-osteoprotegerin system in postmenopausal women with rheumatoid arthritis (RA). The following parameters were investigated in 126 postmenopausal women with RA: IL-6, soluble IL-6-receptor (sIL-6R), soluble glycoprotein 130 (sgp130), sRANKL, osteoprotegerin (OPG), osteocalcin, erythrocyte sedimentation rate and C-reactive protein in sera, pyridinolin and desoxypyridinolin crosslinks in the morning urine. Bone mineral density (BMD) was measured by dual X-ray absorptiometry at the lumbar spine (BMD-LS) and at the femoral neck (BMD-FN). Predictors of RANKL/OPG ratio and BMD were evaluated by multiple linear regression analysis. The following determinants of the RANKL/OPG ratio were identified: sIL-6R/sgp130 ratio and daily glucocorticoid (GC) dose as positive determinants in the whole group (R (2) = 0.56; P = 0.001), sIL-6R/sgp130 ratio as the exclusive positive determinant in patients with GC therapy (R (2) = 0.48; P = 0.001) and sgp130 as negative determinant in patients without GC (R (2) = 0.42; P = 0.031). Sgp130 was highly significantly positively correlated with OPG in the whole group (P < 0.001) as well as in patients with (n = 70; P < 0.05) and without GC therapy (n = 56; P < 0.01). sIL-6R was the main negative predictor of BMD-LS (R (2) = 0.41; P = 0.019). High sIL-6R/sgp130 ratio and/or low sgp130 are associated with a high sRANKL/OPG ratio in sera of postmenopausal women with RA indicating the critical significance of IL-6 trans-signaling for an increase in the RANKL/OPG ratio and of bone resorption. Inhibition of IL-6 trans-signaling may be an effective bone-protecting principle in postmenopausal women with RA.

Topics: Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid; Biomarkers; Bone Density; Cytokine Receptor gp130; Female; Glucocorticoids; Humans; Interleukin-6; Linear Models; Middle Aged; Osteoporosis, Postmenopausal; Osteoprotegerin; Postmenopause; Predictive Value of Tests; RANK Ligand; Receptors, Interleukin-6; Risk Factors; Signal Transduction

The aim of this study was to investigate histological changes of bone marrow in response to tocilizumab for rheumatoid arthritis (RA). After tocilizumab therapy, bone marrow tissues were extracted from ten RA patients at the time of total knee arthroplasty (TKA). Control samples were obtained from ten RA patients who underwent MTX mono-therapy. Histological examination of structural differences between the tocilizumab and control groups in bone marrow was performed using hematoxylin and eosin (H&E) to evaluate differences. In immunohistochemical examination, the expression of seven molecules including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), CD68, osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL), CD4 and osteopontin (OPN) were compared between two groups. NTx was significantly low at 44.5 ± 2 nM BCE/mM Cr compared with control at 73.2 ± 8 nM BCE/mM Cr. Immunohistochemical examination revealed that the bone marrow tissues of the RA patients who underwent tocilizumab therapy demonstrated significant positive OPG as compared with the control. However, immunohistochemical examinations after tocilizumab revealed that TNF-α, IL-6, CD68, CD4, OPN and RANKL were not significantly different with control of MTX in bone marrow. Therefore, treatment with tocilizumab increased the expression of OPG as the histological changes with respect to inhibit RANKL-related bone resorption of bone marrow in RA.

Topics: Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Bone Marrow; Case-Control Studies; Humans; Interleukin-6; Methotrexate; Middle Aged; Osteopontin; Osteoprotegerin; RANK Ligand; Receptors, Interleukin-6; Tumor Necrosis Factor-alpha

Osteoporosis represents an important cause of morbidity in adult rheumatoid arthritis (RA) patients who exhibit increased fracture risk. It is thought that osteoclast and its dysfunction which mediated by many cytokines are the principal pathogenesis of this bone disease, although the mechanisms are still not fully understood. Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B ligand (RANKL) have been revealed in the pathogenesis of primary osteoporosis and other metabolic bone diseases. Thus, the aim of this study was to investigate the possible role of the OPG/RANKL system in RA-related bone loss. A total of 64 Chinese patients with RA and 60 healthy control subjects were involved. Serum levels of OPG and RANKL were measured by ELISA. BMD of nondominant forearm, lumbar spine(L(1-4)) and proximal femur, including femoral neck, Wards triangle, greater trochanter were assessed using dual-energy X-ray absorptiometry. RA patients had a higher incidence of osteoporosis (23/64, 35.9%) than that in healthy controls (9/60, 15.0%) (P < 0.0001). They displayed lower BMD values than controls at positions of all detected region. Compared with healthy controls, RA group showed significantly higher serum levels of RANKL (48.4 ± 12.5 vs. 23.0 ± 11.2 pmol/l, P < 0.0001), lower serum levels of OPG (106.2 ± 40.6 vs. 231.6 ± 65.6 pg/ml, P < 0.0001), and OPG/RANKL ratio (2.4 ± 0.7 vs. 7.0 ± 1.1, P < 0.0001). Multiple linear regression analysis revealed that in RA group, plasma rheumatoid factor concentration (β = -0.187, P = 0.031), swollen joint count (β = 0.567, P = 0.029), BMD at forearm (β = 0.324, P = 0.002), femoral Wards triangle (β = 0.370, P < 0.0001), and lumbar spine (β = 0.313, P = 0.003) were the contributors for serum OPG (R ( 2 ) = 0.718, P < 0.0001). Age (β = 0.241, P = 0.042) and BMD at femoral Wards triangle (β = -0.441, P < 0.0001) and lumbar spine (β = -0.320, P = 0.013) were the determinants for serum RANKL (R ( 2 ) = 0.616, P < 0.0001), while swollen joint count (β = 1.029, P = 0.019) and BMD at femoral neck (β = 0.285, P = 0.042) for serum OPG/RANKL ratio (R ( 2 ) = 0.279, P < 0.011). Analysis of logistic regression showed age (P = 0.004, OR = 1.156, 95% CI: 1.047-1.276) and the level of C-reactive protein (P = 0.028, OR = 1.019, CI 95%: 1.002-1.036) in peripheral blood of RA were the risk factors for the occurrence of osteoporosis in RA, while OPG/RANKL ratio (P = 0.007, OR = 0.035, CI 95%: 0.003-0.400) was the unique protective f

Topics: Adult; Aged; Arthritis, Rheumatoid; Bone Density; Female; Femur; Humans; Lumbar Vertebrae; Male; Middle Aged; Osteoporosis; Osteoprotegerin; Radiography; RANK Ligand

MTHFR polymorphisms C677T and A1298C are associated with reduced MTHFR enzyme activity and hyperhomocysteinemia, which has been associated with osteoporosis. The A163G polymorphism in osteoprotegerin (OPG) has been studied in osteoporosis with controversial results. The objective of the present study was to investigate the association(s) among MTHFR C677T, MTHFR A1298C, and OPG A163G polymorphisms in Mexican patients with rheumatoid arthritis and osteoporosis. The femoral neck and lumbar spine bone mineral densities (BMDs) were measured in 71 RA patients, and genotyping for the three polymorphisms was performed via restriction fragment length polymorphism analysis. Patients with osteoporosis/osteopenia exhibited statistically significant differences in the genotype frequencies of MTHFR C677T as well as an association with femoral neck BMD; TT homozygotes had lower BMDs than patients with the CT genotype, and both of these groups had lower BMDs than patients with the CC genotype. The associations of the MTHFR C677T polymorphism with osteoporosis/osteopenia and femoral neck BMD suggest that these polymorphisms confer a risk of developing osteoporosis in patients with rheumatoid arthritis, a risk that may be reduced with folate and B complex supplementation.

Topics: Adult; Aged; Arthritis, Rheumatoid; Bone Density; Female; Femur Neck; Genetic Association Studies; Haplotypes; Humans; Methylenetetrahydrofolate Reductase (NADPH2); Mexico; Middle Aged; Osteoporosis; Osteoprotegerin; Polymorphism, Restriction Fragment Length; Polymorphism, Single Nucleotide; Statistics, Nonparametric

The receptor activator nuclear factor-kappaB ligand (RANKL) diffuses from articular cartilage to subchondral bone. However, the role of chondrocyte-synthesized RANKL in rheumatoid arthritis-associated juxta-articular bone loss has not yet been explored. This study aimed to determine whether RANKL produced by chondrocytes induces osteoclastogenesis and juxta-articular bone loss associated with chronic arthritis.. Chronic antigen-induced arthritis (AIA) was induced in New Zealand (NZ) rabbits. Osteoarthritis (OA) and control groups were simultaneously studied. Dual X-ray absorptiometry of subchondral knee bone was performed before sacrifice. Histological analysis and protein expression of RANKL and osteoprotegerin (OPG) were evaluated in joint tissues. Co-cultures of human OA articular chondrocytes with peripheral blood mononuclear cells (PBMCs) from healthy donors were stimulated with macrophage-colony stimulating factor (M-CSF) and prostaglandin E2 (PGE2), then further stained with tartrate-resistant acid phosphatase.. Subchondral bone loss was confirmed in AIA rabbits when compared with controls. The expression of RANKL, OPG and RANKL/OPG ratio in cartilage were increased in AIA compared to control animals, although this pattern was not seen in synovium. Furthermore, RANKL expression and RANKL/OPG ratio were inversely related to subchondral bone mineral density. RANKL expression was observed throughout all cartilage zones of rabbits and was specially increased in the calcified cartilage of AIA animals. Co-cultures demonstrated that PGE2-stimulated human chondrocytes, which produce RANKL, also induce osteoclasts differentiation from PBMCs.. Chondrocyte-synthesized RANKL may contribute to the development of juxta-articular osteoporosis associated with chronic arthritis, by enhancing osteoclastogenesis. These results point out a new mechanism of bone loss in patients with rheumatoid arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Blotting, Western; Cartilage, Articular; Cell Differentiation; Chondrocytes; Humans; Immunohistochemistry; Knee Joint; Leukocytes, Mononuclear; Male; Osteoclasts; Osteoprotegerin; Rabbits; RANK Ligand

Bone destruction is a common feature of inflammatory arthritis and is mediated by osteoclasts, the only specialized cells to carry out bone resorption. Aberrant expression of receptor activator of nuclear factor kappa β ligand (RANKL), an inducer of osteoclast differentiation has been linked with bone pathology and the synovial fibroblast in rheumatoid arthritis (RA). In this manuscript, we challenge the current concept that an increase in RANKL expression governs osteoclastogenesis and bone destruction in autoimmune arthritis. We isolated human fibroblasts from RA, pyrophosphate arthropathy (PPA) and osteoarthritis (OA) patients and analyzed their RANKL/OPG expression profile and the capacity of their secreted factors to induce osteoclastogenesis. We determined a 10-fold increase of RANKL mRNA and protein in fibroblasts isolated from RA relative to PPA and OA patients. Peripheral blood mononuclear cells (PBMC) from healthy volunteers were cultured in the presence of RA, PPA and OA synovial fibroblast conditioned medium. Osteoclast differentiation was assessed by expression of tartrate-resistant acid phosphatase (TRAP), vitronectin receptor (VNR), F-actin ring formation and bone resorption assays. The formation of TRAP(+), VNR(+) multinucleated cells, capable of F-actin ring formation and lacunar resorption in synovial fibroblast conditioned medium cultures occured in the presence of osteoprotegerin (OPG) a RANKL antagonist. Osteoclasts did not form in these cultures in the absence of macrophage colony stimulating factor (M-CSF). Our data suggest that the conditioned medium of pure synovial fibroblast cultures contain inflammatory mediators that can induce osteoclast formation in human PBMC independently of RANKL. Moreover inhibition of the TNF or IL-6 pathway was not sufficient to abolish osteoclastogenic signals derived from arthritic synovial fibroblasts. Collectively, our data clearly show that alternate osteoclastogenic pathways exist in inflammatory arthritis and place the synovial fibroblast as a key regulatory cell in bone and joint destruction, which is a hallmark of autoimmune arthritis.

Topics: Acid Phosphatase; Actins; Arthritis, Rheumatoid; Bone Resorption; Cell Differentiation; Cells, Cultured; Chondrocalcinosis; Culture Media, Conditioned; Fibroblasts; Gene Expression Regulation; Humans; Integrin alphaVbeta3; Interleukin-6; Isoenzymes; Leukocytes, Mononuclear; Osteoarthritis; Osteoclasts; Osteoprotegerin; RANK Ligand; Signal Transduction; Synovial Fluid; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor-alpha

The immunoreceptor tyrosine-based activation motif (ITAM) pathway provides osteoclast co-stimulatory signals and regulates proliferation, survival and differentiation of effector immune cells. In the osteoclast, the receptors Triggering Receptor Expressed on Myeloid cells 2 (TREM2) and Osteoclast Associated Receptor (OSCAR) and their respective adaptor proteins, DAP12 and FcRγ mediate ITAM signals and induce calcium signaling and the crucial transcription factor, NFATc1. In rheumatoid arthritis (RA), OSCAR expression by monocytes is inversely correlated with disease activity. Additionally, serum levels of OSCAR are reduced in RA patients versus healthy controls suggesting that expression and secretion or cleavage of soluble (s) OSCAR is immune modulated. Recent data suggest that endothelial cells may also be a source of OSCAR.. ITAM receptors, their adaptor proteins, and NFATc1 and cathepsin K were detected in human synovial tissues by immunohistochemistry. Synovial tissues from patients with active RA were compared with tissue from patients in remission, osteoarthritis (OA) patients and healthy individuals. OSCAR was measured by immunoassay in synovial fluids recovered from active RA and OA patients. Endothelial cells were cultured with or without 5 ng/mL TNF-α or IL-1β over 72 hours. Temporal expression of OSCAR mRNA was assessed by qRT PCR and OSCAR protein in the supernatant was measured by ELISA.. Significantly higher (P < 0.05) NFATc1-positive inflammatory cell aggregates were found in active RA tissues than in healthy synovial tissue. Similarly, the percentage of OSCAR, FcRγ, DAP12 and TREM2 positive cells was significantly higher in active RA tissues compared to the healthy synovial tissue. Notably, OSCAR was strongly expressed in the microvasculature of the active RA tissues (9/9), inactive RA (8/9) weakly in OA (4/9) but only in the lumen of healthy synovial tissue (0/8). OSCAR levels were detected in synovial fluids from both RA (47 to 152 ng/mL) and OA (112 to 145 ng/mL) patients. Moreover, OSCAR mRNA expression and soluble OSCAR release was stimulated by TNF-α and IL1-β in cultured endothelial cells.. Increased levels of ITAM related factors were present in synovial tissue from active RA joints compared to OA and healthy joints. OSCAR was strongly expressed by the vasculature of active RA patients and membrane bound and soluble OSCAR was stimulated by inflammatory mediators in endothelial cells in vitro.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Aged, 80 and over; Antirheumatic Agents; Arthritis, Rheumatoid; Cells, Cultured; Endothelial Cells; Female; Gene Expression; Humans; Immunohistochemistry; Interleukin-1beta; Joints; Male; Membrane Glycoproteins; Membrane Proteins; Microscopy, Confocal; Middle Aged; NFATC Transcription Factors; Osteoprotegerin; Receptors, Cell Surface; Receptors, Fc; Receptors, Immunologic; Reverse Transcriptase Polymerase Chain Reaction; Synovial Membrane; Tumor Necrosis Factor-alpha

TSG-6 (the product of tumor necrosis factor [TNF]-stimulated gene 6) has a potent inhibitory effect on RANKL-mediated bone erosion. The aim of this study was to compare the activity of TSG-6 with that of osteoprotegerin (OPG) and to investigate its role as an autocrine modulator of cytokine-mediated osteoclast formation/activation. We also determined TSG-6 expression in inflammatory joint disease.. The effects of TSG-6, OPG, and the inflammation mediators TNFα, interleukin-1 (IL-1), and IL-6 on the formation of osteoclasts from peripheral blood mononuclear cells and synovial fluid (SF) macrophages were determined by tartrate-resistant acid phosphatase staining. Lacunar resorption and filamentous actin ring formation were measured as indicators of osteoclast activity. The amount of TSG-6 in culture media or SF was quantified by enzyme-linked immunosorbent assay, and expression of TSG-6 in synovial tissue was assessed by immunohistochemistry.. TSG-6 acted in synergy with OPG to inhibit RANKL-mediated bone resorption and was produced by osteoclast precursors and mature osteoclasts in response to TNFα, IL-1, and IL-6. Expression of TSG-6 correlated with inhibition of lacunar resorption; this effect was ameliorated by an anti-TSG-6 antibody. The level of TSG-6 protein was determined in SF from patients with various arthritides; it was highest in patients with inflammatory conditions such as rheumatoid arthritis, in which it correlated with the amount of TSG-6 immunostaining in the synovium. TSG-6 inhibited the activation but not the formation of osteoclasts from SF macrophages.. In the presence of inflammatory cytokines, osteoclasts produced TSG-6 at concentrations that are sufficient to inhibit lacunar resorption. This may represent an autocrine mechanism to limit the degree of bone erosion during joint inflammation.

Topics: Aged; Arthritis, Psoriatic; Arthritis, Rheumatoid; Autocrine Communication; Bone Resorption; Cell Adhesion Molecules; Cell Differentiation; Cells, Cultured; Female; Humans; Interleukin-1; Interleukin-6; Macrophages; Male; Osteoarthritis, Knee; Osteoclasts; Osteoprotegerin; Tumor Necrosis Factor-alpha

Results of studies in mice suggest a protective role for TRAIL in arthritis. The aim of this study was to investigate the role of TRAIL in patients with rheumatoid arthritis (RA).. In the present study, we compared RA fibroblast-like synoviocytes (FLS) that were resistant or sensitive to TRAIL-induced apoptosis and the expression of TRAIL receptors in these cells, and also investigated the clinical features of the patients from whom the FLS were derived. Furthermore, we evaluated the levels of TRAIL and its soluble decoy receptor osteoprotegerin (OPG) in patients with RA, patients with osteoarthritis (OA), and patients with spondylarthritis (SpA).. Sensitivity to TRAIL-induced apoptosis varied in FLS from different patients, and the severity of disease in patients with RA was inversely correlated with the susceptibility of their FLS to TRAIL-induced apoptosis. TRAIL-sensitive cells expressed significantly lower levels of TRAILR-1, and silencing of TRAILR-1 increased TRAIL-induced apoptosis in RA FLS. TRAIL levels were elevated in the arthritic joints of patients with established RA, and TRAIL levels in the synovial fluid of these patients were elevated compared with levels in the synovial fluid of patients with OA or SpA. At baseline, a low OPG-to-TRAIL ratio in the sera of patients with early RA was associated with a better evolution of disease activity, but high serum levels of TRAIL at followup were associated with joint damage.. These findings suggest that TRAIL has a dual role in RA, and that the resistance of RA FLS to TRAIL-induced apoptosis is associated with a disease-promoting activity of TRAIL in RA.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Apoptosis; Arthritis, Rheumatoid; Female; Fibroblasts; Humans; Interleukin-6; Interleukin-8; Male; Middle Aged; Osteoarthritis; Osteoprotegerin; Severity of Illness Index; Spondylarthritis; Synovial Membrane; TNF-Related Apoptosis-Inducing Ligand; Young Adult

The role of B cells in inflammatory bone formation and resorption is controversial. We investigated this in patients with rheumatoid arthritis (RA) treated with rituximab, a B-cell depleting antibody. We found a significant suppression in bone turnover, possibly a direct effect or as a consequence of a reduction in inflammation and disease activity.. RA is the most prevalent inflammatory joint disease, in which B cells play an important role. However, the role of B cells in bone turnover is controversial and RA subjects treated with rituximab, a B-cell depleting monoclonal antibody, provide an ideal model for determining the role of B cells in inflammatory bone resorption.. Serum from 46 RA patients, collected pre- and post-rituximab therapy, was analysed for biomarkers of bone turnover (procollagen type I amino-terminal propeptide [P1NP], osteocalcin, β-isomerised carboxy-terminal telopeptide of type 1 collagen [βCTX] and osteoprotegerin [OPG]).. A significant decrease in bone resorption was observed 6 months after rituximab (median change βCTX -50 ng/L, 95%CI -136, -8 p < 0.001, this equates to -37%; 95%CI -6, -49), mirrored by a reduction in disease activity. Similarly, there was a significant increase in P1NP, a marker of bone formation (median change P1NP 5.0 μg/L, 95%CI -1.0, 11.2, p = 0.02; 13%; 95%CI -3, 39), but no significant change in osteocalcin or OPG levels. The percentage change from baseline of βCTX in a subgroup of patients (not on prednisolone or bisphosphonate) was significantly correlated with the percentage reduction in DAS28 score (r (s) = 0.570, p = 0.014).. In conclusion, we have found that B-cell depletion increases bone formation and decreases bone resorption in RA patients; this may be a direct effect on osteoblasts and osteoclasts, respectively, and be at least partially explained by the decreased inflammation and disease activity.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Murine-Derived; Antirheumatic Agents; Arthritis, Rheumatoid; B-Lymphocytes; Bone Regeneration; Bone Remodeling; Collagen Type I; Female; Humans; Male; Middle Aged; Osteoprotegerin; Peptide Fragments; Peptides; Procollagen; Rituximab

To demonstrate that posttranslational modification of type II collagen (CII) by reactive oxygen species (ROS), which are known to be present in inflamed arthritic joints, can give rise to epitopes specific to damaged cartilage in rheumatoid arthritis (RA) and osteoarthritis (OA) and to establish a proof of concept that antibodies specific to ROS-modified CII can be used to target therapeutics specifically to inflamed arthritic joints.. We used a semisynthetic phage display human antibody library to raise single-chain variable fragments (scFv) specific to ROS-modified CII. The specificity of anti-ROS-modified CII scFv to damaged arthritic cartilage was assessed in vitro by immunostaining articular cartilage from RA and OA patients and from normal controls. The in vivo targeting potential was tested using mice with antigen-induced arthritis, in which localization of anti-ROS-modified CII scFv in the joints was determined. The therapeutic effect of anti-ROS-modified CII scFv fused to soluble murine tumor necrosis factor receptor II-Fc fusion protein (mTNFRII-Fc) was also investigated.. The anti-ROS-modified CII scFv bound to damaged arthritic cartilage from patients with RA and OA but not to normal preserved cartilage. When systemically administered to arthritic mice, the anti-ROS-modified CII accumulated selectively at the inflamed joints. Importantly, when fused to mTNFRII-Fc, it significantly reduced inflammation in arthritic mice, as compared with the effects of mTNFRII-Fc alone or of mTNFRII-Fc fused to an irrelevant scFv.. Our findings indicate that biologic therapeutics can be targeted specifically to arthritic joints and suggest a new approach for the development of novel treatments of arthritis.

Topics: Animals; Arthritis, Rheumatoid; Cartilage; Cartilage, Articular; Cattle; Disease Models, Animal; Epitopes; Humans; Immunoglobulin Fc Fragments; Immunohistochemistry; Mice; Mice, Inbred C57BL; Osteoarthritis; Osteoprotegerin; Reactive Oxygen Species; Single-Chain Antibodies

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation of the joints, which may lead to structural damage of the cartilage and bone. The receptor activator of nuclear factor-kappaB (RANK) and the osteoprotegerin (OPG) cascade system have been reported to be essential in osteoclastogenesis. Genetic variations in the genes coding for RANK, RANK ligand (RANKL), and OPG are thought to play roles in the susceptibility to RA.. In our case-control study, genomic DNA was obtained from 534 patients with RA who fulfilled the American College of Rheumatology 1987 criteria and 516 healthy control blood donors (HC). We studied 7 single-nucleotide polymorphisms (SNP) in the genes of RANK (2 SNP: rs1805034, rs35211496), OPG (2 SNP: rs3102735, rs2073618), and RANKL (3 SNP: rs9533156, rs2277438, rs1054016) using TaqMan assay-guided polymerase chain reaction. Genotype and allelic frequencies comparing RA patients with HC were analyzed by chi-square test for 2 x 3 and 2 x 2 tables, respectively.. Genotype distributions of the SNP rs35211496 in the RANK gene as well as the SNP rs2277438 in the RANKL gene differed significantly between patients with RA and HC. The frequency of the minor allele of rs9533156 of RANKL was significantly higher in patients with RA than in HC (OR 0.84, 95% CI 0.71-0.99, p = 0.047). Multivariate analysis adjusted to sex and investigating SNP demonstrated a significantly elevated risk for RA associated with the major allele in the RANK SNP rs35211496 (p = 0.0231) and with the minor allele in the RANKL SNP rs2277438 (p = 0.0092). No significantly increased risk was detected in the other SNP.. The minor allele of the RANK SNP rs35211496 may be protective against RA, while the minor alleles of the RANKL SNP rs2277438 may increase susceptibility to RA.

Topics: Adolescent; Adult; Aged; Alleles; Arthritis, Rheumatoid; Case-Control Studies; Chi-Square Distribution; Female; Genetic Predisposition to Disease; Genetic Variation; Genotype; Humans; Male; Middle Aged; Osteoprotegerin; Polymerase Chain Reaction; Polymorphism, Single Nucleotide; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Regression Analysis

To investigate the influence of a combined therapy consisting of dexamethasone and osteoprotegerin (OPG) on bone alterations and disease activity in antigen-induced arthritis (AIA) in the rat.. AIA rats received dexamethasone (0.25 mg kg(-1) day(-1), i.p.), OPG (2.5 mg kg(-1) day(-1), i.p.), or a combination of both at regular intervals for 21 consecutive days. At the end of the treatment, bone structure was analyzed by histomorphometry. Primary spongiosa was measured using linear scanning.. AIA led to significant periarticular and axial bone loss. Dexamethasone monotherapy substantially suppressed joint swelling without inhibiting bone loss of the secondary spongiosa, whereas OPG monotherapy showed no anti-inflammatory effect. Despite reduction of bone resorption, OPG did not inhibit AIA-induced bone loss. In contrast, the combination of dexamethasone and OPG not only produced an anti-inflammatory effect, but also resulted in inhibition of periarticular and axial bone loss. OPG increased trabecular number of the primary spongiosa whilst combination therapy led to an increase in both trabecular number and trabecular width.. The principle of combining a glucocorticoid together with inhibition of the receptor activator of NF-kappaB ligand (RANKL) may be an effective bone-saving therapy in rheumatoid arthritis.

Topics: Animals; Antigens; Arthritis, Experimental; Arthritis, Rheumatoid; Bone and Bones; Bone Resorption; Dexamethasone; Drug Therapy, Combination; Female; Knee Joint; NF-kappa B; Osteoprotegerin; Radiography; RANK Ligand; Rats; Rats, Inbred Lew

To assess the relationship between serum concentrations of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and osteoprotegerin (OPG) and the therapeutic response to disease-modifying antirheumatic drugs (DMARD) in patients with early rheumatoid arthritis (RA).. Circulating levels of TRAIL and its soluble receptor OPG were measured by ELISA in paired serum samples obtained from 66 patients with early RA at their first visit (baseline) and after 1 year of therapy. Levels of TRAIL and OPG were analyzed in relation to the clinical response, defined by the 28-joint count Disease Activity Score (DAS28).. Both serum TRAIL and OPG increased after DMARD therapy. Baseline levels of TRAIL, but not OPG, were significantly higher (p < 0.05) in the patients that achieved a clinical response by DAS28 after 1 year of therapy, versus patients without clinical response to DMARD. Baseline serum levels of TRAIL were higher (p < 0.01) in rheumatoid factor-negative patients.. Our data suggest that the basal level of circulating TRAIL is an important determinant in the therapeutic response to DMARD in patients with early RA.

Topics: Aged; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Disease Progression; Female; Humans; Middle Aged; Osteoprotegerin; Severity of Illness Index; TNF-Related Apoptosis-Inducing Ligand; Treatment Outcome

Rheumatoid arthritis (RA) is characterized by inflammation of the synovial membrane, leading to invasion of synovial tissue into the adjacent cartilage matrix with degradation of articular cartilage and bone as a consequence. Dickkopf-1 (DKK-1) and osteoprotegerin (OPG) have been demonstrated to be key molecules involved in bone erosion and bone remodeling. The aim of this study was to explore the potential role of DKK-1 and OPG in different stage of RA.. The protein levels of DKK-1 and OPG were detected by ELISA. The serum samples were collected from 300 patients with RA and 60 healthy controls. Of which, 150 RA patients were defined as early RA (disease duration < or = 1 year), and other 150 RA patients were defined as longlasting RA (disease duration > or = 5 years). At the time of serum sampling, various clinical and laboratory parameters were assessed. The correlations of DKK-1 or OPG and clinical/laboratory parameters were analyzed.. The serum level of DKK-1 was elevated in patients with longstanding RA compared with healthy controls, while no significant difference was observed between the two groups in the level of OPG. In contrast, in early RA patients, the circulating OPG was elevated, while there was no significant difference between the two groups in expression of DKK-1. The serum DKK-1 was correlated with Sharp score and DAS28 in longstanding RA patients. In early RA, age was the only parameter that was significantly related to serum OPG.. There was a cross-talk between DKK-1 and OPG, which involved in bone destruction in RA. In different stage of RA, DKK-1 and OPG may play different roles in the pathogenesis of RA.

Topics: Adult; Arthritis, Rheumatoid; Enzyme-Linked Immunosorbent Assay; Female; Humans; Intercellular Signaling Peptides and Proteins; Male; Middle Aged; Osteoprotegerin; Time Factors

In chronic arthritis cartilage and bone destruction occur as a consequence of synovial inflammation. It is mainly mediated by matrix metalloproteinases and RANKL-OPG pathways. Data on synovial fluid levels of these mediators in enthesitis related arthritis subtype (ERA) of JIA are not available. MMP-1, MMP-3, TIMP, sRANKL and OPG levels were measured in synovial fluid from patients with ERA and compared with other arthritides, polyarticular (Poly) JIA, RA and osteoarthritis (OA). sRANKL was detectable in 25/41 of ERA patients, 4/16 of Poly JIA patients. Median SF sRANKL level in patients with ERA was higher as compared to OA (p < 0.001) and poly JIA (p < 0.05) but were comparable to RA. The median OPG level in ERA was lower as compared to OA (p < 0.001), comparable to RA but was higher than poly JIA (p < 0.001). sRANKL/OPG ratio was significantly higher in ERA and Poly JIA compared to OA (p < 0.0001, p < 0.0001 respectively). The median MMP3 levels in ERA (74 microg/ml) was lower as compared to poly JIA (410 microg/ml; p < 0.0001) and RA (340 ug/ml; p < 0.0001) but was comparable to OA (107 microg/ml). The median level of ProMMP1 in ERA (0.70 microg/ml) was lower as compared to RA (2.9 microg/ml; p < 0.0001) and poly JIA but was elevated as compared to OA patients (0.1 microg/ml; p < 0.0001). TIMP1 levels in ERA were higher than poly JIA and RA patients. MMP3/TIMP1 ratio was lower in ERA compared to polyarticular JIA patients (p < 0.05). Ours is the first study reporting elevated sRANKL and reduced OPG levels and elevated sRANKL/OPG ratio in SF of children with JIA resulting in a mileu associated with bone loss. In addition, ERA patients had lower MMP level as well as MMP/TIMP ratio as compared to poly JIA which may partly explain lesser degree of joint damage seen in ERA as compared to poly JIA.

Topics: Adolescent; Adult; Aged; Arthritis, Juvenile; Arthritis, Rheumatoid; Child; Child, Preschool; Female; Humans; Male; Matrix Metalloproteinases; Middle Aged; Osteoarthritis; Osteoprotegerin; RANK Ligand; Synovial Fluid; Tissue Inhibitor of Metalloproteinase-1

The objective of this study is to determine the effects of adrenomedullin (AM) on IL-1- and TNF-alpha-induced rheumatoid synovial fibroblasts (RASFs)-mediated osteoclastogenesis. The formation of osteoclasts in co-cultures of RASFs and peripheral blood mononuclear cells was evaluated by tartrate-resistant acid phosphatase and resorption pit formation assay. The expression of RANKL, OPG, p-ERK, p-p38, and p-JNK was examined by immunoblotting and quantitative reverse transcription-polymerase chain reaction. AM (1-52) inhibits IL-1- and TNF-alpha-induced RASFs-mediated osteoclastogenesis. AM affected IL-1-, TNF-alpha-induced RANKL and OPG expression in RASFs. AM also inhibits IL-1 and TNF-alpha-induced phosphorylation of ERK-1/2, p38 MAPK, and JNK. Inhibitor of AM (AM 22-52) inhibits the effects of AM on the osteoclastogenesis. These results suggest that AM might be involved in the inflammatory cytokines-mediated osteoclastogenesis and thus bone damage, and indicate that it can be a new therapeutic strategy against joint destruction in RA.

Topics: Acid Phosphatase; Adrenomedullin; Arthritis, Rheumatoid; Coculture Techniques; Fibroblasts; Humans; Interleukin-1; Isoenzymes; Leukocytes, Mononuclear; Mitogen-Activated Protein Kinases; Osteoclasts; Osteoprotegerin; RANK Ligand; Recombinant Proteins; RNA, Messenger; Synovial Membrane; Tartrate-Resistant Acid Phosphatase; Time Factors; Tumor Necrosis Factor-alpha

As current predictors of joint destruction have low specificity, serological biomarkers reflecting bone and cartilage destruction have been proposed as tools in assessing prognosis of rheumatoid arthritis (RA). We examined whether serum concentrations of a panel of biomarkers could predict radiographic progression in patients with RA.. A cohort of 238 patients with RA was followed longitudinally for 10 years with collection of clinical data and serum samples. These analyses focus on the 136 patients with radiographs of the hands available at baseline and at 5 and/or 10 years. Radiographs were scored according to the van der Heijde-modified Sharp score (SHS). Baseline sera were analyzed for receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), human cartilage glycoprotein-39 (YKL-40), C2C, collagen cross-linked C-telopeptide (CTX-I), and cartilage oligomeric matrix protein (COMP). Multivariate linear and logistic regression analyses were used to identify predictors of radiographic progression.. Baseline CTX-I levels were higher in progressors [0.41 ng/ml (interquartile range 0.31-0.75)] than in nonprogressors [0.32 ng/ml (IQR 0.21-0.49)], and were independently associated with 10-year change in radiographic damage score [ss = 16.4 (IQR 5.7-27.1)]. We found no association between radiographic progression and baseline serum levels of RANKL, OPG, C2C, YKL-40, or COMP.. This longterm followup study of patients with RA indicates a relationship between elevated CTX-I levels in serum and subsequent joint destruction. This association was, however, weak, and our study does not support that serum CTX-I or any of the other tested biomarkers will serve as more useful prognostic markers than current predictors such as anti-cyclic citrullinated peptide, radiographic damage early in the disease course, and signs of inflammation.

Topics: Adipokines; Adult; Aged; Arthritis, Rheumatoid; Arthrography; Biomarkers; Bone and Bones; Cartilage; Cartilage Oligomeric Matrix Protein; Chitinase-3-Like Protein 1; Cohort Studies; Collagen Type I; Disease Progression; Extracellular Matrix Proteins; Female; Glycoproteins; Humans; Lectins; Longitudinal Studies; Male; Matrilin Proteins; Middle Aged; Osteoprotegerin; Peptides; RANK Ligand; Severity of Illness Index; Time Factors

Complement activation products contribute to a large number of inflammatory diseases, including RA. We have investigated whether osteoprotegerin (OPG) may concur with the soluble terminal complement complex (SC5b-9) to the inflammatory cascade characterizing RA.. Levels of SC5b-9 and OPG in the plasma and SF of patients with active RA were determined by ELISA. The presence of SC5b-9 and OPG in RA synovial lesions was analysed by immunohistochemistry. Cultured endothelial cells were used for in vitro leucocyte/endothelial cell adhesion assays. In addition, endothelial cells were exposed to SC5b-9 in order to evaluate the effects on the production of OPG protein, as well as the activation of the OPG promoter.. Patients affected by active RA are characterized by elevated levels of both SC5b-9 and OPG in plasma and/or SF. Of note, we have observed a co-localization of SC5b-9 and OPG in endothelial cells of post-capillary venules of RA synovial lesions. Data on endothelial cell cultures showed that exposure to SC5b-9 induced the up-regulation of OPG expression/release, stimulating the transcriptional activity of the OPG promoter, and synergized with TNF-alpha in up-regulating OPG production.. Our findings demonstrate that SC5b-9 induces OPG production by endothelial cells and we propose that the SC5b-9-mediated up-regulation of OPG may be an important mechanism whereby complement contributes in promoting and/or enhancing the inflammation in RA.

Topics: Adult; Aged; Arthritis, Rheumatoid; Cell Adhesion; Cells, Cultured; Complement Membrane Attack Complex; Dose-Response Relationship, Drug; Endothelial Cells; Endothelium, Vascular; Female; Humans; Male; Middle Aged; Neutrophil Infiltration; Neutrophils; Osteoprotegerin; Synovial Membrane; Up-Regulation

Mesenchymal stem cells (MSCs) are characterized by their hematopoiesis-supporting and immunosuppressive capacity, while osteoclasts are main cell components in the endosteal hematopoietic stem cell niche and pivotal players in osteoimmunology. To clarify the association of these 2 kinds of cells, mouse CD11b(+) monocytes were cultured onto MSC layers in the presence or absence of macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL). The results showed that MSCs independently supported osteoclast development and this effect was enhanced by M-CSF and RANKL. Interestingly, tumor necrosis factor-alpha (TNF-alpha)-stimulated MSCs turned to inhibit osteoclast formation and protect tusk slices from osteoclastic resorption. Real-time PCR and ELISA assays demonstrated that osteoprotegerin expression at both mRNA and protein levels in TNF-alpha-stimulated MSCs was up-regulated, at least partially by activating the mitogen-activated protein kinase pathway. Furthermore, TNF-alpha-stimulated MSCs maintained their immunophenotypic, multipotential differentiation and immunosuppressive characteristics. Moreover, MSCs treated with synovial fluid from rheumatoid arthritis patients modulated osteoclast generation in close relation with the TNF-alpha levels. This study suggests that MSCs exhibit dual modulatory function on osteoclasts and the result might shed light on understanding the involvement of MSCs in the inflammatory diseases.

Topics: Animals; Arthritis, Rheumatoid; CD11b Antigen; Cell Differentiation; Enzyme Activation; Female; Humans; Immune Tolerance; Immunophenotyping; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Monocytes; Multipotent Stem Cells; Osteoclasts; Osteoprotegerin; RNA, Messenger; Solubility; Synovial Fluid; Tumor Necrosis Factor-alpha; Up-Regulation

Topics: Arthritis, Rheumatoid; Cells, Cultured; Drug Interactions; Fibroblasts; Humans; Osteoprotegerin; Recombinant Proteins; Synovial Membrane; TNF-Related Apoptosis-Inducing Ligand

Rat adjuvant-induced arthritis (AIA) and collagen-induced arthritis (CIA) feature bone loss and systemic increases in TNFalpha, IL-1beta, and receptor activator of NF-kappaB ligand (RANKL). Anti-IL-1 or anti-TNFalpha therapies consistently reduce inflammation in these models, but systemic bone loss often persists. RANKL inhibition consistently prevents bone loss in both models without reducing joint inflammation. Effects of these therapies on systemic markers of bone turnover and inflammation have not been directly compared.. Lewis rats with established AIA or CIA were treated for 10 days (from day 4 post onset) with either PBS (Veh), TNFalpha inhibitor (pegsunercept), IL-1 inhibitor (anakinra), or RANKL inhibitor (osteoprotegerin (OPG)-Fc). Local inflammation was evaluated by monitoring hind paw swelling. Bone mineral density (BMD) of paws and lumbar vertebrae was assessed by dual X-ray absorptiometry. Markers and mediators of bone resorption (RANKL, tartrate-resistant acid phosphatase 5b (TRACP 5B)) and inflammation (prostaglandin E2 (PGE2), acute-phase protein alpha-1-acid glycoprotein (alpha1AGP), multiple cytokines) were measured in serum (day 14 post onset).. Arthritis progression significantly increased paw swelling and ankle and vertebral BMD loss. Anti-TNFalpha reduced paw swelling in both models, and reduced ankle BMD loss in AIA rats. Anti-IL-1 decreased paw swelling in CIA rats, and reduced ankle BMD loss in both models. Anti-TNFalpha and anti-IL-1 failed to prevent vertebral BMD loss in either model. OPG-Fc reduced BMD loss in ankles and vertebrae in both models, but had no effect on paw swelling. Serum RANKL was elevated in AIA-Veh and CIA-Veh rats. While antiTNFalpha and anti-IL-1 partially normalized serum RANKL without any changes in serum TRACP 5B, OPG-Fc treatment reduced serum TRACP 5B by over 90% in both CIA and AIA rats. CIA-Veh and AIA-Veh rats had increased serum alpha1AGP, IL-1beta, IL-8 and chemokine (C-C motif) ligand 2 (CCL2), and AIA-Veh rats also had significantly greater serum PGE2, TNFalpha and IL-17. Anti-TNFalpha reduced systemic alpha1AGP, CCL2 and PGE2 in AIA rats, while anti-IL-1 decreased systemic alpha1AGP, IL-8 and PGE2. In contrast, RANKL inhibition by OPG-Fc did not lessen systemic cytokine levels in either model.. Anti-TNFalpha or anti-IL-1 therapy inhibited parameters of local and systemic inflammation, and partially reduced local but not systemic bone loss in AIA and CIA rats. RANKL inhibition prevented local and systemic bone loss without significantly inhibiting local or systemic inflammatory parameters.

Topics: Animals; Antirheumatic Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Density; Enzyme-Linked Immunosorbent Assay; Immunohistochemistry; Inflammation; Interleukin 1 Receptor Antagonist Protein; Interleukin-1; Osteoprotegerin; RANK Ligand; Rats; Rats, Inbred Lew; Tumor Necrosis Factor-alpha

To demonstrate the effect of treatment with disease-modifying agents on the expression of osteoprotegerin (OPG) and RANKL in the synovial tissue from rheumatoid arthritis (RA) patients and to correlate these changes with radiologic damage measured on sequential radiographs of the hands and feet.. Synovial biopsy specimens were obtained at arthroscopy from 25 patients with active RA (16 of whom had a disease duration <12 months) before and at 3-6-month intervals after starting treatment with a disease-modifying agent. Immunohistologic analysis was performed using monoclonal antibodies to detect OPG and RANKL expression, with staining quantitated using computer-assisted image analysis and semiquantitative analysis techniques. Serial radiographs of the hands and feet were analyzed independently by 2 radiologists and a rheumatologist using the van der Heide modification of the Sharp scoring method.. Thirteen patients achieved a low disease state as defined by a disease activity score <2.6 while 19 patients achieved an American College of Rheumatology response >20% after disease-modifying antirheumatic drug (DMARD) treatment. Successful DMARD treatment resulted in an increase in OPG expression and a decrease in RANKL expression at the synovial tissue level, which correlated with a reduction in erosion scores measured on annual radiographs of the hands and feet.. Successful treatment-induced modulation of OPG and RANKL expression at the synovial tissue level, resulting in a reduction in the RANKL:OPG ratio, is likely to have a significant impact on osteoclast formation and joint damage in patients with active RA.

Topics: Aged; Aged, 80 and over; Antirheumatic Agents; Arthritis, Rheumatoid; Female; Follow-Up Studies; Humans; Knee Joint; Male; Middle Aged; Osteoprotegerin; Radiography; RANK Ligand; Severity of Illness Index; Synovial Membrane

Topics: Aged; Arthritis, Rheumatoid; Biomarkers; Case-Control Studies; Female; Humans; Male; Middle Aged; Osteoprotegerin; Prognosis; RANK Ligand; TNF-Related Apoptosis-Inducing Ligand

To determine whether proinflammatory cytokine treatment or the complete absence of select cytokines modulates the expression of RANKL and osteoprotegerin (OPG) in synovial fibroblasts.. Fibroblasts were isolated from normal and rheumatoid human synovium and from normal or arthritic joints of wild-type and cytokine gene-deficient (interleukin-4-knockout [IL-4 (-/-)] and interferon-gamma-knockout [IFNgamma (-/-)]) mice. Fibroblasts were stimulated with proinflammatory cytokines (tumor necrosis factor alpha [TNFalpha], IL-1beta, and IL-17) or antiosteoclastogenic cytokines (IL-4 and IFNgamma), alone or in combination, and the expression of RANKL and OPG was measured.. Proinflammatory cytokine-stimulated fibroblasts from rheumatoid and arthritic mouse joints expressed higher levels of RANKL and OPG than those from normal joints. IL-4 suppressed RANKL expression and increased OPG expression, IFNgamma reduced the production of both RANKL and OPG, and IL-17 had only a modest effect on the expression of RANKL or OPG. Additive effects of combination treatment (TNFalpha/IL-17 or IL-1beta/IL-17) were observed only in the human system. Extensive destruction was observed in the arthritic joints of IL-4 (-/-) mice, with a corresponding upward shift of the RANKL:OPG ratios. However, an IL-17 deficiency did not attenuate arthritis or reduce bone resorption.. Proinflammatory cytokines induce the expression of RANKL and OPG in both human and murine synovial fibroblasts. The RANKL:OPG ratios are shifted in favor of bone protection by IL-4 treatment, and, to a lesser extent, by IFNgamma treatment. Unexpectedly, an IL-17 deficiency alone does not induce reduced inflammatory bone destruction. Our results suggest that synovial fibroblasts may significantly contribute to bone resorption through modulation of RANKL and OPG production in a cytokine-rich milieu of inflamed joints.

Topics: Animals; Arthritis, Rheumatoid; Bone Resorption; Cells, Cultured; Cytokines; Dose-Response Relationship, Drug; Fibroblasts; Humans; Interferon-gamma; Interleukin-17; Interleukin-1beta; Interleukin-4; Mice; Mice, Inbred BALB C; Mice, Knockout; Osteoprotegerin; RANK Ligand; Synovial Membrane; Tumor Necrosis Factor-alpha

The mechanisms of osteoclast maturation and the role of rheumatoid arthritis (RA) synovial fibroblasts in the control of osteoclastogenesis remain unclear. The purpose of this study was to determine the humoral factors that influence osteoclast differentiation resulting from mutual interactions between osteoclast progenitor cells and synovial fibroblasts.. The cloned mouse macrophage cell line RAW 264.7 or isolated human CD14+ monocytes were cocultured with RA or osteoarthritis (OA) synovial fibroblasts in the presence of RANKL. Osteoclasts were visualized by staining for tartrate-resistant acid phosphatase (TRAP), and their functions were evaluated by bone resorption assay. Transforming growth factor beta (TGFbeta) and osteoprotegerin (OPG) levels were measured by enzyme-linked immunosorbent assay. Expression of pSmad2 and Smad7 was analyzed by Western blotting.. RANKL-mediated osteoclast formation was observed in cocultures of RAW cells with RA synovial cells, but not with OA synovial cells. This formation was inhibited by TGFbeta receptor kinase inhibitor or neutralizing TGFbeta antibody. Human CD14+ monocytes showed the same results with RAW 264.7, and bone resorption activity was consistent with osteoclast formation. RA synovial fibroblasts produced TGFbeta in response to cell-cell contact with RAW cells in a RANKL-dependent manner. TGFbeta reduced OPG production by RA synovial fibroblasts, but dose-dependently increased OPG secretion in OA synovial fibroblasts. TGFbeta decreased the expression of pSmad2 and increased the expression of Smad7 in RA synovial fibroblasts, but not OA synovial fibroblasts.. Suppression of OPG production by down-regulation of TGFbeta/Smad2 signaling may contribute to RANKL-mediated osteoclastogenesis from RA synovial fibroblasts.

Topics: Animals; Arthritis, Rheumatoid; Bone Resorption; Cell Differentiation; Cell Line; Cloning, Organism; Down-Regulation; Fibroblasts; Humans; Mice; Monocytes; Osteoarthritis; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad7 Protein; Synovial Membrane; Transforming Growth Factor beta

Topics: Antirheumatic Agents; Arthritis, Rheumatoid; Drug Therapy, Combination; Gene Expression Regulation; Glucocorticoids; Humans; Osteoprotegerin; RANK Ligand; Severity of Illness Index; Synovial Membrane; Tumor Necrosis Factor-alpha

To examine the effects of infliximab on bone resorption by osteoclast precursor cells (OCPs) in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) and to compare the results with changes in disease activity.. Before and during 24 weeks of infliximab treatment, peripheral blood mononuclear cells of 9 RA and 10 AS patients were seeded onto ivory wafers and adherent cells, including OCPs, were grown in medium promoting osteoclast differentiation. Bone resorption was evaluated morphometrically and correlated to disease activity. A total of 19 healthy individuals were studied in parallel. In addition, biochemical bone markers were assessed in all patients at baseline and after 24 weeks.. OCPs from RA patients showed a higher bone resorption at baseline when compared to AS patients. Blocking of tumour necrosis factor (TNF)alpha with infliximab resulted in a strong reduction of bone resorption by OCPs in both cohorts and occurred faster in RA compared to AS patients. This inhibition coincided with a reduction of clinical disease activity in both patient cohorts and with an increase of serum osteocalcin levels and a relative decrease of collagen crosslinks in RA compared to AS patients.. These results provide an explanation on the cellular level for the anticatabolic effect of TNF neutralisation on bone. The variation in the kinetics of bone resorption by the OCPs in patients with RA and AS suggests disease-specific differences in the type or in the preactivation of OCPs.

Topics: Adult; Aged; Amino Acids; Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Bone Resorption; Case-Control Studies; Cells, Cultured; Female; Humans; Infliximab; Male; Middle Aged; Osteocalcin; Osteoclasts; Osteoprotegerin; RANK Ligand; Spondylitis, Ankylosing; Tumor Necrosis Factor-alpha

Osteoprotegerin (OPG) and soluble receptor activator of NF-kappa B ligand (sRANKL) together regulate the bone metabolism among other cytokines, whereby cathepsin K has a potent collagen-degrading activity. An imbalance of this system may be partly responsible for the skeletal complications of RA. Expanding on a previous study, we investigated the relationship between OPG, sRANKL and cathepsin K levels in the serum of patients with longstanding RA. We measured serum levels of OPG, sRANKL and cathepsin K of 100 patients with active, longstanding RA. We detected elevated serum levels of cathepsin K (median 54.8 pmol/l) and OPG (median 4.8 pmol/l), but normal sRANKL levels (median 0.2 pmol/l). Cathepsin K did not show a correlation with the overexpressed OPG (P=0.64) and sRANKL (P=0.81). The radiological destruction correlates significantly with cathepsin K (P=0.004) and OPG (P=0.007). We speculate that the increased levels of OPG are effective in compensating the action of sRANKL, but do not directly prevent bone degradation, as reflected by the elevated serum levels of cathepsin K.

Topics: Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid; Biomarkers; Cathepsin K; Cathepsins; Humans; Middle Aged; Osteoprotegerin; RANK Ligand

To elucidate the role of the synovium in bone destruction by osteoclasts in rheumatoid arthritis (RA), primary synovial cells isolated from RA patients were cultured and characterized. The cultured primary cells did not produce RANKL (TRANCE/ODF/OPGL/TNFSF11/CD254), an inducer of osteoclast differentiation, but constitutively produced its inhibitor, osteoprotegerin (OPG). Addition of TNF-alpha to the primary cultures of synovial cells reduced the cell viability and strongly suppressed OPG production. We then established nine synovial cell clones, including SYM-1, responsible for OPG production from primary synovial cell cultures. TNF-alpha induced apoptosis of SYM-1 cells within 24h and decreased OPG levels, while infliximab, a chimerical form of the anti-TNF-alpha antibody drug, suppressed the apoptosis and restored OPG levels. These results suggest the existence of fibroblastic cells producing OPG in the synovium, while TNF-alpha suppresses OPG production by inducing apoptosis in those cells. Further, infliximab is considered to inhibit bone destruction through restoration of OPG levels in RA.

Topics: Adult; Aged; Antibodies, Monoclonal; Antirheumatic Agents; Apoptosis; Arthritis, Rheumatoid; Cell Differentiation; Cell Survival; Cells, Cultured; Female; Fibroblasts; Humans; Infliximab; Male; Middle Aged; Osteoclasts; Osteoprotegerin; RANK Ligand; Synovial Membrane; Tumor Necrosis Factor-alpha

The aim of this study was to investigate sRANKL and OPG levels in serum and synovial fluid (SF) and to evaluate their relations in patients with RA in comparison to those with non-erosive arthritis (NEA). The study included 45 unselected RA patients with knee joint effusions and 27 patients with knee joint effusions because of NEA. Serum and SF samples were investigated isochronously. OPG and sRANKL were measured by ELISA assays. In RA, sRANKL levels were higher in serum than in SF (P = 0.007). In contrast, the NEA revealed higher sRANKL in SF compared to the serum (P = 0.001). Though in RA the average levels of sRANKL(ser) were 5.6 times and of sRANKL(syn) 1.5 times higher than in NEA, the differences were not significant. The free (unbound) OPG in SF was not significantly different in RA compared to NEA. Also in serum, the measured free OPG was only slightly higher in RA. There were no significant differences between RA and NEA concerning ESR and CRP. Significant correlations could be found between sRANKL(syn )and CRP (r = 0.453; P = 0.005) as well as ESR (r = 0.362; P = 0.033) in RA. Nearly a positive correlation was evident also between sRANKL(syn) and CRP in NEA (r = 0.520; P = 0.08). RA and NEA differ in particular concerning their power and intensity to destruct the juxtaarticular bone. This is the most remarkable finding of this study, that in RA a high part of sRANKL seems to be OPG bound and cleared by the blood stream, but the sRANKL neutralizing capacity of produced OPG in opposite to NEA is not sufficient to prevent osteoclast activation and bone destruction in the RA joint.

Topics: Adult; Arthritis, Rheumatoid; Biomarkers; Blood Sedimentation; C-Reactive Protein; Chronic Disease; Female; Humans; Inflammation; Male; Middle Aged; Osteoprotegerin; RANK Ligand; Solubility; Synovial Fluid

Spondylarthritis (SpA) and rheumatoid arthritis (RA) have different patterns of bone damage, with more pronounced bone erosions in RA. The RANK/RANKL/osteoprotegerin (OPG) system plays a central role in bone resorption by promoting the maturation and activation of osteoclasts. To assess the potential role of this system in the distinct bone phenotype, we studied the synovial expression of these mediators in SpA and RA peripheral synovitis.. Synovial biopsy specimens were obtained from the actively inflamed peripheral joints of 35 patients with SpA and 19 patients with RA. Paired synovial biopsy samples were obtained from 24 patients with SpA after tumor necrosis factor alpha (TNFalpha) blockade. Synovial tissue sections were immunostained for RANKL, OPG, RANK, and TRAP and assessed by semiquantitative scoring and digital image analysis.. After extensive validation of the reactivity and specificity of the antibodies, we demonstrated the abundant expression of RANKL and OPG in SpA synovitis. RANKL was expressed by both fibroblast-like synoviocytes and sublining T lymphocytes. RANK-positive osteoclast precursors but no mature TRAP-positive osteoclasts were present in the inflamed tissue. The expression of these mediators was not different between patients with nonpsoriatic SpA, patients with psoriatic SpA, and patients with RA, was not related to the degree of systemic or local inflammation, and was not significantly modulated by highly effective treatment with TNFalpha blockers. Only the subset of patients with the best systemic response to TNFalpha blockade had decreased RANKL expression in the intimal lining layer.. The relative protection against bone erosions in SpA cannot be explained by qualitative or quantitative differences in the synovial expression of RANKL, OPG, and RANK. The abundant expression of these factors in SpA peripheral synovitis is largely disconnected from systemic and local inflammation.

Topics: Adult; Aged; Arthritis, Rheumatoid; Biopsy; Bone and Bones; Female; Humans; Inflammation; Male; Middle Aged; Osteoblasts; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Spondylarthritis; Synovial Membrane; Tumor Necrosis Factor-alpha

Topics: Arthritis, Rheumatoid; Biopsy; Bone and Bones; Humans; Osteoblasts; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Spondylarthritis; Synovial Membrane

The effects of soluble TNF-alpha receptor, etanercept, on bone metabolism were investigated in patients with rheumatoid arthritis (RA). Thirty RA patients were administered etanercept once or twice a week for more than 6 months. We evaluated clinical and laboratory parameters and measured urinary excretion levels of pyridinoline (PYD), deoxypyridinoline (DPD), cross-linked N-telopeptides of type I collagen (NTX), and serum levels of bone alkaline phosphatase (BAP), osteoprotegerin (OPG), and soluble receptor activator of NFkappaB ligand (sRANKL) at the baseline and at 3 and 6 months after initial treatment with etanercept. Etanercept treatment resulted in an improvement of symptoms due to RA and in a reduction of urinary excretion levels of PYD and DPD as well as serum sRANKL levels, with a significant difference at 6 months, and an increase of serum BAP levels at 3 and 6 months after the initial treatment with etanercept. Urinary NTX and serum OPG levels did not show a significant change at 3 and 6 months after the initial treatment, but serum OPG levels did show a reverse correlation with serum CRP levels, suggesting that the regulation of inflammation in RA may result in an induction of OPG production. Etanercept may have the ability to reduce the levels of bone resorption markers and to increase the levels of a bone formation marker while reducing sRANKL formation in RA patients.

Topics: Alkaline Phosphatase; Amino Acids; Arthritis, Rheumatoid; Biomarkers; Bone and Bones; Collagen Type I; Etanercept; Female; Humans; Immunoglobulin G; Male; Middle Aged; Osteoprotegerin; Peptides; RANK Ligand; Receptors, Tumor Necrosis Factor

Functional links between bone remodeling and the immune system in chronic inflammatory arthritis are mediated, in part, by the ligand of receptor activator of nuclear factor-kappa-B (RANK-L). Because neutrophils play a crucial role in chronic inflammation, the goal of this study was to determine whether proteins of the RANK/RANK-L pathway are expressed by synovial fluid (SF) neutrophils from patients with rheumatoid arthritis (RA) and to characterize this pathway in normal human blood neutrophils. The expression of RANK-L, osteoprotegerin (OPG), RANK, and tumor necrosis factor receptor-associated factor 6 (TRAF6) was determined by polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and cytofluorometry. RANK signaling was analyzed by the degradation of inhibitor of kappaB-alpha (I-kappaB-alpha). SF neutrophils from patients with RA express and release OPG and express the membrane-associated forms of RANK-L and RANK. In contrast, normal blood neutrophils express only the membrane-associated form of RANK-L. They do not express the mRNAs encoding OPG and RANK. SF neutrophils from RA patients and normal blood neutrophils release no soluble RANK-L. They express the mRNA for TRAF6. The expression of OPG and RANK by normal human blood neutrophils, however, can be induced by interleukin-4 + tumor necrosis factor-alpha and by SFs from patients with RA. In contrast, SFs from patients with osteoarthritis do not induce the expression of OPG and RANK. Moreover, the addition of RANK-L to normal blood neutrophils pretreated by SF from patients with RA decreased I-kappaB-alpha, indicating that RANK signaling by neutrophils stimulated with SF is associated with nuclear factor-kappa-B activation. In summary, RANK-L is expressed by inflammatory and normal neutrophils, unlike OPG and RANK, which are expressed only by neutrophils exposed to an inflammatory environment. Taken together, these results suggest that neutrophils may contribute to bone remodeling at inflammatory sites where they are present in significantly large numbers.

Topics: Arthritis, Rheumatoid; Blotting, Western; Bone Remodeling; Enzyme-Linked Immunosorbent Assay; Female; Humans; I-kappa B Proteins; Inflammation; Male; Middle Aged; Neutrophils; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synovial Fluid; TNF Receptor-Associated Factor 6

The aim of our study was to investigate determinants of bone mineral density (BMD) measured by dual X-ray absorptiometry at the lumbar spine (BMD-LS) and at the femoral neck (BMD-FN) in patients with rheumatoid arthritis (RA) with special respect to bone resorbing proinflammatory cytokines and their physiological antagonists. In 142 RA patients the following parameters were measured in parallel with BMD: serum levels of soluble receptor activator of nuclear factor kappa-B-ligand (sRANKL), osteoprotegerin (OPG), interleukin (IL)-6, soluble glycoprotein 130 (sgp130), 25-hydroxyvitamin D3 (25OHD(3)), 1,25-dihydroxyvitamin D3 (1,25[OH](2)D(3)), intact parathyroid hormone, osteocalcin, ionized calcium, renal excretion of pyridinolin and deoxypyridinolin, C-reactive protein, and erythrocyte sedimentation rate (ESR). No significant differences of sRANKL, OPG, IL-6, and spg130 were found between patients with osteoporosis (47.9% of patients), osteopenia (36.6%), and normal BMD (15.5%). However, total sRANKL was significantly higher in postmenopausal women with osteoporosis at FN than in those without (p < 0.05) and showed a negative correlation with BMD-LS in patients older than 60 years (p = 0.01). BMD-LS and BMD-FN (p < 0.001) and total sRANKL (p < 0.01) were negatively related with the age of the patients. Only IL-6 (positive correlation, p < 0.001) and 1,25(OH)(2)D(3) (negative correlation, p < 0.001) but not sRANKL, OPG, and sgp130 were related to disease activity. Using multiple linear regression analysis, menopause was identified as the crucial negative determinant of BMD-LS (R (2) = 0.94, p = 0.001), whereas cumulative glucocorticoid dose (beta = -0.80, p = 0.001) and ESR (beta = -0.44, p = 0.016) were the negative determinants of BMD-FN (R (2) = 0.86, p = 0.001). The results indicate that influences of age and gender must be considered in investigations on the relationship between BMD and sRANKL in RA and that high serum levels of sRANKL seems to be associated with osteoporosis only in subgroups of RA patients.

Topics: Absorptiometry, Photon; Adolescent; Adult; Aged; Aged, 80 and over; Arthritis, Rheumatoid; Biomarkers; Bone Density; Bone Resorption; Disease Progression; Female; Humans; Incidence; Male; Middle Aged; Osteoprotegerin; Prognosis; RANK Ligand; Severity of Illness Index

Osteoprotegerin (OPG), a soluble decoy receptor for receptor activator of nuclear factor kappaB ligand, is implicated in the pathogenesis of atherosclerosis. Patients with rheumatoid arthritis (RA) have inflammation and increased atherosclerosis. We examined the hypothesis that OPG concentrations are increased in patients with RA and are associated with coronary-artery atherosclerosis. Serum OPG concentrations were measured by ELISA and coronary-artery calcification by electron-beam computer tomography in 157 patients with RA and 87 control subjects. OPG concentrations were higher in patients with long-standing RA (n=67) [median (interquartile range)]: [1895 (1337-2847) pg/mL, and early RA (n=90): [1340 (1021-1652) pg/mL, than controls 1068 (692-1434) pg/mL; (p<0.001)]. In patients with RA, OPG concentrations were associated with erythrocyte sedimentation rate (p<0.001), homocysteine (p=0.001), disease duration (p=0.02), coronary calcium score (p=0.03), and cumulative dose of corticosteroids (p=0.04) after adjustment for age and sex. In patients with long-standing RA, OPG was associated with coronary-artery calcification independently of cardiovascular risk factors and disease activity [OR for every increase in 500 pg/mL of OPG=2.22 (1.43-3.34), p<0.001]. In conclusion, OPG concentrations are increased in patients with RA and are associated with inflammation. In patients with long-standing disease, OPG is independently associated with coronary-artery calcification.

Topics: Adult; Aged; Arthritis, Rheumatoid; Biomarkers; Calcinosis; Case-Control Studies; Coronary Artery Disease; Female; Humans; Male; Middle Aged; Osteoprotegerin; Radiography; Time Factors

The objective of this study was to investigate whether baseline receptor activator for nuclear factor kappaB ligand (RANKL) and osteoprotegerin (OPG) serum (s) levels can predict the therapeutic response to TNF antagonists (a-TNF).. We studied 75 rheumatoid arthritis patients (81% female) with a longstanding refractory disease. The variables of disease activity, physical function and sRANKL and sOPG levels were determined before and after both 12-14 and 28-30 weeks of a-TNF therapy (65 adalimumab, 10 infliximab). Remission was defined by a 28 joint count disease activity score (DAS28) /=1.2 at both 3- and 7-month follow-up visits.. In most patients, disease activity was severe, as reflected by a baseline DAS28 score of 5.9+/-1 (mean+/-SD), an HAQ of 1.6 (1.1 to 2.1) (median (interquartile range (IQR))) and a CRP 15 mg/l (IQR: 9 to 24). The sRANKL levels and RANKL/OPG ratio in patients that achieved remission were significantly lower at baseline than in the remaining patients at both 3 and 7 months of follow-up. The sOPG levels correlated with the HAQ and the physician's disease assessment and diminished significantly after a-TNF treatment. However, no significant association was detected between the therapeutic response profile and sOPG levels.. These data suggest that in patients receiving a-TNF treatment, lower serum levels of RANKL and RANKL/OPG ratio may serve to predict remission.

Topics: Adalimumab; Adult; Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antirheumatic Agents; Arthritis, Rheumatoid; Biomarkers; Female; Humans; Infliximab; Joints; Logistic Models; Male; Middle Aged; Osteoprotegerin; Prognosis; RANK Ligand; Remission Induction; Tumor Necrosis Factor-alpha

We examined associations between human leukocyte antigen DRB1 (HLA-DRB1) shared epitope (SE), receptor activator of nuclear factor-kappaB (RANK), RANK ligand (RANKL), osteoprotegerin (OPG), and interleukin 17 (IL-17) genotypes with age of disease onset and radiographic progression in Japanese patients with early rheumatoid arthritis (RA). HLA-DRB1 genotypes were evaluated in 123 patients with early RA (98 female, 25 male) within 1 year of symptom onset. In 72 patients, radiographic progression over a 2-year period was evaluated using Larsen's methods, and genotypes of three polymorphic sites in RANK, five sites in RANKL, two sites in OPG, and three sites in IL-17 were determined by direct polymerase chain reaction sequencing. Possession of an SE allele was significantly associated with earlier disease onset in females (median 46.9 vs 51.9 years in SE- patients; P = 0.04). Single nucleotide polymorphisms (SNPs) in RANKL (rs2277438, P = 0.028) and IL-17 (rs3804513, P = 0.049) were significantly associated with radiographic progression at 2 years. RANKL-G-, SE- patients (n = 12) had significantly less joint damage than did RANKL-G+, SE- patients (n = 11; P = 0.0038), RANKL-G-, SE+ patients (n = 21; P = 0.0018) and RANKL-G+, SE+ patients (n = 28; P = 0.0024). In Japanese RA patients, HLA-DRB1 SE alleles are associated with disease onset at an earlier age, as has been observed in Caucasian RA patients. In addition, SNPs in RANKL and IL-17 may be associated with radiographic progression in Japanese patients with early RA.

Topics: Adult; Alleles; Arthritis, Rheumatoid; Disease Progression; DNA; Female; Follow-Up Studies; Genetic Predisposition to Disease; Genotype; HLA-DR Antigens; HLA-DRB1 Chains; Humans; Interleukin-17; Male; Middle Aged; Osteoprotegerin; Phenotype; Polymerase Chain Reaction; Polymorphism, Genetic; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Retrospective Studies

Treatment of rheumatoid arthritis (RA) with tumor necrosis factor (TNF)-blocking agents, including etanercept and infliximab, has resulted in reductions in the radiographic progression of RA. However, the exact mechanism by which this protection occurs has not been determined. In order to add to such knowledge, we investigated the effect of anti-TNF therapy on the expression of osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (RANKL) in synovial tissue.. The expression of OPG and RANKL in synovial biopsy specimens was evaluated by immunohistochemistry. Serial synovial biopsy specimens were obtained from 18 patients with RA, before and after treatment with etanercept (9 patients) or infliximab (9 patients). Biopsy specimens were evaluated by double-blind semiquantitative analysis and image analysis. The in vitro effect of TNF antagonists on the RANKL/OPG expression in osteoblasts and endothelial cells was evaluated by Western blotting. Statistical analysis was performed using Wilcoxon's signed rank test, followed by the Bonferroni correction for multiple comparisons of paired samples. The results of in vitro experiments were evaluated by one-way analysis of variance, with Tukey's post hoc test.. Treatment with both infliximab and etanercept increased the expression of OPG in synovial tissue. After 8 weeks of treatment, neither infliximab nor etanercept influenced RANKL expression. In both groups of patients, the RANKL:OPG ratio decreased following therapy. In vitro, both of the TNF antagonists mimicked the in vivo effect, inducing a decrease in the RANKL:OPG ratio in TNF-primed osteoblasts and endothelial cells.. Therapy with TNF antagonists in RA modulates the OPG/RANKL system, a potential mechanism that could explain the retardation of radiographic damage observed following anti-TNF therapy.

Topics: Adult; Aged; Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Carrier Proteins; Etanercept; Female; Glycoproteins; Humans; Immunoglobulin G; Infliximab; Male; Membrane Glycoproteins; Middle Aged; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Synovial Membrane; Tumor Necrosis Factor-alpha

Topics: Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Glycoproteins; Humans; Membrane Glycoproteins; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) have been demonstrated to be critical regulators of osteoclast generation and activity. In addition, RANKL has been implicated as an important mediator of bone erosion in rheumatoid arthritis (RA). However, the expression of RANKL and OPG at sites of pannus invasion into bone has not been examined. The present study was undertaken to further elucidate the contribution of this cytokine system to osteoclastogenesis and subsequent bone erosion in RA by examining the pattern of protein expression for RANKL, OPG and the receptor activator of NF-kappaB (RANK) in RA at sites of articular bone erosion.. Tissues from 20 surgical procedures from 17 patients with RA were collected as discarded materials. Six samples contained only synovium or tenosynovium remote from bone, four samples contained pannus-bone interface with adjacent synovium and 10 samples contained both synovium remote from bone and pannus-bone interface with adjacent synovium. Immunohistochemistry was used to characterize the cellular pattern of RANKL, RANK and OPG protein expression immediately adjacent to and remote from sites of bone erosion.. Cellular expression of RANKL protein was relatively restricted in the bone microenvironment; staining was focal and confined largely to sites of osteoclast-mediated erosion at the pannus-bone interface and at sites of subchondral bone erosion. RANK-expressing osteoclast precursor cells were also present in these sites. OPG protein expression was observed in numerous cells in synovium remote from bone but was more limited at sites of bone erosion, especially in regions associated with RANKL expression.. The pattern of RANKL and OPG expression and the presence of RANK-expressing osteoclast precursor cells at sites of bone erosion in RA contributes to the generation of a local microenvironment that favours osteoclast differentiation and activity. These data provide further evidence implicating RANKL in the pathogenesis of arthritis-induced joint destruction.

Topics: Adolescent; Adult; Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Cell Differentiation; Child; Child, Preschool; Glycoproteins; Humans; Immunohistochemistry; Joints; Membrane Glycoproteins; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Synovial Membrane

Our objective was to clarify the heterogeneity in response to infliximab treatment in rheumatoid arthritis (RA); to this end, a bioassay was designed to explore the contribution of circulating tumour necrosis factor (TNF)-alpha bioactivity and its possible link to response. The bioassay is based on the induction of IL-6 and osteoprotegerin (OPG) production by synoviocytes in response to TNF-alpha. RA synoviocytes were cultured with TNF-alpha (5 ng/ml) and 42 RA plasma samples collected just before starting therapy. Levels of IL-6 and OPG were measured in supernatants. In 20 of the patients, plasma samples collected before and 4 hours after the first and the ninth infusions were tested in the same way. Plasma concentrations of TNF-alpha and p55 and p75 soluble receptors were measured using ELISA. TNF-alpha induced IL-6 and OPG production by synoviocytes, which was further increased with patient plasma dilutions and inhibited by infliximab. With plasma samples obtained before the first infusion, the IL-6-induced production was greater in patients with a good clinical response than in the poor responders (44.4 +/- 23.3 ng/ml versus 27.4 +/- 20.9 ng/ml; P = 0.05). This high circulating TNF-alpha bioactivity was strongly inhibited with the first infliximab infusion. The difference between IL-6 levels induced with plasma samples obtained before and 4 hours after the first infusion was greater in patients with a good clinical response (40.0 +/- 23.7 ng/ml versus 3.4 +/- 10.0 ng/ml; P = 0.001). Similar findings were obtained for OPG production (7.0 +/- 6.2 ng/ml versus 0.0 +/- 3.0 ng/ml; P < 0.05). Levels of circulating TNF-alpha bioactivity were predictive of clinical response to TNF-alpha inhibition, confirming a key role for TNF-alpha in these RA patients.

Topics: Adult; Aged; Antibodies, Monoclonal; Arthritis, Rheumatoid; Autoimmune Diseases; Biological Assay; Cells, Cultured; Female; Gene Expression Regulation; Glycoproteins; Humans; Individuality; Infliximab; Infusions, Intravenous; Interleukin-6; Male; Middle Aged; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Synovial Membrane; Treatment Outcome; Tumor Necrosis Factor-alpha

We studied the effects of estrogen on human fibroblast-like synovial cells in rheumatoid arthritis (RA-FLS) focusing on receptor activator of NF-kappaB ligand (RANKL) and its decoy receptor osteoprotegerin (OPG), the osteoclast formation and function regulators that have a substantial role in bone erosion of RA. Estrogen influences osteoporosis and the onset of RA clinically. The cellular responses of RA-FLS to estrogen are initiated via two high-affinity estrogen receptors (ERs). Culture of RA-FLS in the presence of 10(-6) M 17beta-estradiol (E2) increased expression of estrogen receptor (ER)-alpha, but not ER-beta. OPG mRNA expression was significantly increased, whereas RANKL mRNA was unaffected. E2 treatment also significantly increased the amount of OPG released in the culture supernatant. The increase of OPG and ER-alpha was specifically antagonized by the pure estrogen antagonist ICI 182780. Tamoxifen, a selective ER moderator, did not increase OPG. The results indicate that estrogen stimulates secretion of OPG from RA-FLS by acting on ER-alpha, which likely prevents bone erosion in RA.

Topics: Arthritis, Rheumatoid; Carrier Proteins; Cells, Cultured; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogen Receptor Modulators; Estrogens; Fibroblasts; Fulvestrant; Glycoproteins; Humans; Membrane Glycoproteins; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Synovial Membrane; Tamoxifen; Up-Regulation

We examined OPG and soluble RANKL in the serum (sOPG, sRANKL) and synovial fluid (synOPG, synRANKL) in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). OPG and RANKL were measured in 85 patients (44 with RA, 41 patients with OA) in serum and synovial fluid as well. For measuring of OPG and RANKL ELISA tests were used. The results of OPG and RANKL were compared with clinical and radiological scores. We found a negative correlation for OPG and RANKL in synovial fluids: not only for the whole group of patients (P < 0.003, r = -0.32), but also for the subgroups (RA: P < 0.04, r = -0.28, OA: P < 0.002, r = -0.54). SRANKL and synRANKL were positively correlated in the whole group (P < 0.01, r = 0.25) and in the OA group (P < 0.02, r = 0.35); the RA group was showing a trend (P < 0.063, r = 0.24), however. Serum OPG was lower in RA, synOPG higher in OA. The difference between the two patient groups was only significant for synOPG (P < 0.03, r = 0.056), but not for sOPG (P < 0.09, r = 0.19), sRANKL (P < 0.43, r = 0.85) or synRANKL (P < 0.11, r = 0.22). The synOPG:synRANKL ratio was significantly correlated with the Larsen score (P < 0.004, r = 0.38). Synovial OPG is significantly decreased in rheumatoid joints, whereby synovial RANKL is increased. Lower synOPG could reflect a lower protective effect on bone, thus leading to an earlier and more pronounced bone destruction in RA. However, the effect of different mediators for joint destruction in RA and OA seems not to be important to the pathophysiological changes in the joints. The upregulation of serum OPG might be the result of the inflammation; in contrast, an upregulation of RANKL could not be found in the serum of patients with RA and OA.

Topics: Aged; Aged, 80 and over; Arthritis, Rheumatoid; Carrier Proteins; Enzyme-Linked Immunosorbent Assay; Female; Glycoproteins; Humans; Male; Membrane Glycoproteins; Middle Aged; Osteoarthritis; Osteoprotegerin; Radiography; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Severity of Illness Index; Synovial Fluid

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease involving the breakdown of cartilage and juxta-articular bone, which is often accompanied by decreased bone mineral density (BMD) and increased risk of fracture. Anti-inflammatory omega-3 fatty acids may prevent arthritis and bone loss in MRL/lpr mice model of arthritis and in humans.. In this study, the effect of long term feeding of 10% dietary n-3 (fish oil (FO)) and n-6 (corn oil (CO)) fatty acids begun at 6 weeks of age on bone mineral density (BMD) in different bone regions in an MRL/lpr female mouse model of RA was measured at 6, 9, and 12 months of age by dual energy x-ray absorptiometry (DEXA). After sacrificing the mice at 12 months of age, antioxidant enzyme activities were measured in spleen, mRNA for receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) was measured by RT-PCR in lymph nodes, and synovitis was measured in leg joints.. At 6, 9 and 12 months of age, BMD was significantly higher (p < 0.05) in distal femur, proximal tibia, and lumbar spine of FO fed mice than those of CO fed mice. Spleen catalase (CAT) and superoxide dismutase (SOD) activities were also significantly higher (p < 0.01) in FO fed mice than in CO fed mice. Histology of knee joints revealed mild synovitis in CO fed mice, which was not present in FO fed mice. RT-PCR analysis of lymph nodes revealed decreased RANKL mRNA (p < 0.001) expression and enhanced OPG mRNA expression (p < 0.01) in FO fed mice compared to CO fed mice.. These results suggest beneficial effects of long-term FO feeding in maintaining higher BMD and lower synovitis in this mouse model. These beneficial effects may be due, in part, to increased activity of antioxidant enzymes, decreased expression of RANKL, and increased expression of OPG in FO fed mice thereby altering the RANKL/OPG ratio. These significant beneficial effects on BMD suggest that FO may serve as an effective dietary supplement to prevent BMD loss in patients with RA.

Topics: Absorptiometry, Photon; Animals; Arthritis, Rheumatoid; Autoimmune Diseases; Bone Density; Carrier Proteins; Catalase; Corn Oil; Disease Models, Animal; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Female; Fish Oils; Glycoproteins; Membrane Glycoproteins; Mice; Mice, Inbred MRL lpr; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Superoxide Dismutase; Synovitis; Time Factors

Heme oxygenase 1 (HO-1) plays an important role in vascular disease, transplantation, and inflammation. In animal models of acute and chronic inflammation, induction of HO-1 has anti-inflammatory and cytoprotective properties. Since inflammation is an important trigger of osteoclastogenesis, we hypothesized that HO-1 might influence osteoclastogenesis. We investigated the effects of induction of HO-1 on osteoclast formation in vitro and in vivo. Furthermore, we addressed the role of HO-1 in inflammatory bone loss in humans. When HO-1 was induced by hemin in vitro, a significant dose-dependent inhibition of osteoclastogenesis was observed. Up-regulation of HO-1 was mediated by activation of MAPK and primarily prevented differentiation of osteoclast precursors to osteoclasts, whereas it did not affect mature osteoclasts. Anti-osteoclastogenic properties of hemin were based on a down-regulation of c-fms, RANK, TRAF-6, and c-fos. In addition, induction of HO-1 inhibited TNF-triggered osteoclast differentiation in vitro as well as LPS-driven inflammatory bone loss in vivo. Furthermore, HO-1 induction suppressed osteoclastogenesis and bone destruction in a TNF-mediated arthritis. In line, assessment of synovial tissue from rheumatoid arthritis patients revealed that osteoclasts are usually HO-1 negative. Moreover, serum levels of bilirubin, a metabolite of HO-1, were elevated in rheumatoid arthritis patients without bone damage, suggesting HO-1 affects bone loss in humans. In summary, these data indicate that HO-1 negatively regulates osteoclastogenesis, leading to a positive net balance of bone.

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Rheumatoid; Bilirubin; Bone and Bones; Bone Resorption; Cell Nucleus; Dose-Response Relationship, Drug; Down-Regulation; Enzyme Activation; Glycoproteins; Heme Oxygenase-1; Hemin; Humans; In Vitro Techniques; Inflammation; Lipopolysaccharides; Mice; Models, Biological; Osteoclasts; Osteoprotegerin; Proto-Oncogene Proteins c-fos; Receptor, Macrophage Colony-Stimulating Factor; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Spleen; TNF Receptor-Associated Factor 6; Up-Regulation

Osteoprotegerin (OPG) is a secreted member of the TNF receptor superfamily. OPG is made by osteoblastic cells and is expressed in a wide variety of cell and tissue types. It acts as a decoy receptor by binding the receptor activator of nuclear factors kB (RANKL) and preventing RANKL-induced osteoclast formation and differentiation. Numerous cytokines and hormones (TGF-beta, PTH, vitamin D, glucocorticoids and oestrogens) exert their effects on osteoclastogenesis by regulating the production of OPG.. In the present study we compared serum OPG and RANKL concentrations in a group of normal children (1-14 years old) with those of pair-aged children affected by different diseases [Turner's syndrome (TS), early/precocious puberty (PP) and rheumatoid arthritis (RA)]. OPG and RANKL concentrations were measured by an enzyme immunoassay method using a commercial kit.. Mean (+/- SD) OPG level in normal children was 4.05 +/- 1.63 pmol/l with no difference between males and females. OPG values in children 1-4 years old (5.87 +/- 2.22 pmol/l) were significantly higher than in children 4-14 years old (3.55 +/- 0.97 pmol/l). OPG levels in children with RA were significantly higher than in controls (6.33 +/- 2.57 pmol/l vs. 4.05 +/- 1.63 pmol/l, P < 0.01); patients with TS or PP had OPG levels superimposable to those of controls (2.61 +/- 0.67 pmol/l and 3.99 +/- 0.85 pmol/l, respectively), but in TS OPG levels were significantly lower than in age-matched females. Mean RANKL concentration in normal subjects was 0.81 +/- 1.55 pmol/l; there was a slight decline in RANKL levels with age. RANKL concentrations in subjects with TS, PP, RA and controls did not differ significantly, and did not differ from those published in adult normal subjects.. It appears from our data that OPG serum levels in healthy children aged > 4 years are similar to those present in young adult men, with higher levels in the first 4 years of life. Although the meaning of the alterations of OPG levels observed in pathological conditions is still obscure, they appear potentially interesting in view of a key role played by this protein in bone homeostasis.

Topics: Aging; Arthritis, Rheumatoid; Carrier Proteins; Case-Control Studies; Child; Child, Preschool; Female; Glycoproteins; Homeostasis; Humans; Infant; Male; Membrane Glycoproteins; Osteoprotegerin; Puberty, Precocious; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reference Values; Turner Syndrome

Topics: Adult; Arthritis, Rheumatoid; Carrier Proteins; Female; Glycoproteins; Humans; Joints; Male; Membrane Glycoproteins; Middle Aged; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

The aims of this study were to evaluate the in vivo effects of estrogen deficiency in MRL/lpr mice as a model for rheumatoid arthritis and to analyze the possible relationship between immune dysregulation and receptor activator of nuclear factor-kappaB ligand (RANKL)-mediated osteoclastogenesis. Experimental studies were performed in ovariectomized (Ovx)-MRL/lpr, Ovx-MRL+/+, sham-operated-MRL/lpr, and sham-operated-MRL+/+ mice. Severe autoimmune arthritis developed in younger Ovx-MRL/lpr mice until 24 wk of age, whereas these lesions were entirely recovered by pharmacological levels of estrogen administration. A significant elevation in serum rheumatoid factor, anti-double-stranded DNA, and anti-type II collagen was found in Ovx-MRL/lpr mice and recovered in mice that underwent estrogen administration. A high proportion of CD4(+) T cells bearing RANKL was found, and an enhanced expression of RANKL mRNA and an impaired osteoprotegerin mRNA was detected in the synovium. An increase in both osteoclast formation and bone resorption pits was found. These results indicate that estrogen deficiency may play a crucial role in acceleration of autoimmune arthritis associated with RANKL-mediated osteoclastogenesis in a murine model for rheumatoid arthritis.

Topics: Animals; Arthritis; Arthritis, Rheumatoid; Autoimmune Diseases; Bone Resorption; Carrier Proteins; Cytokines; Disease Models, Animal; Estrogens; Female; Gene Expression; Glycoproteins; Joints; Matrix Metalloproteinase 3; Matrix Metalloproteinase 9; Membrane Glycoproteins; Mice; Osteoclasts; Osteoprotegerin; Ovariectomy; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

To investigate the efficacy of single and combined blockade of tumor necrosis factor (TNF), interleukin-1 (IL-1), and RANKL pathways on synovial inflammation, bone erosion, and cartilage destruction in a TNF-driven arthritis model.. Human TNF-transgenic (hTNFtg) mice were treated with anti-TNF (infliximab), IL-1 receptor antagonist (IL-1Ra; anakinra), or osteoprotegerin (OPG; an OPG-Fc fusion protein), either alone or in combinations of 2 agents or all 3 agents. Synovial inflammation, bone erosion, and cartilage damage were evaluated histologically.. Synovial inflammation was inhibited by anti-TNF (-51%), but not by IL-1Ra or OPG monotherapy. The combination of anti-TNF with either IL-1Ra (-91%) or OPG (-81%) was additive and almost completely blocked inflammation. Bone erosion was effectively blocked by anti-TNF (-79%) and OPG (-60%), but not by IL-1Ra monotherapy. The combination of anti-TNF with IL-1Ra, however, completely blocked bone erosion (-98%). Inhibition of bone erosion was accompanied by a reduction of osteoclast numbers in synovial tissue. Cartilage destruction was inhibited by anti-TNF (-43%) and was weakly, but not significantly, inhibited by IL-1Ra, but was not inhibited by OPG monotherapy. The combination of anti-TNF with IL-1Ra was the most effective double combination therapy in preventing cartilage destruction (-80%). In all analyses, the triple combination of anti-TNF, IL-1Ra, and OPG was not superior to the double combination of anti-TNF and IL-1Ra.. Articular changes caused by chronic overexpression of TNF are not completely blockable by monotherapies that target TNF, IL-1, or RANKL. However, combined approaches, especially the combined blockade of TNF and IL-1 and, to a lesser extent, TNF and RANKL, lead to almost complete remission of disease. Differences in abilities to block synovial inflammation, bone erosion, and cartilage destruction further strengthen the rationale for using combined blockade of more than one proinflammatory pathway.

Topics: Animals; Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Bone and Bones; Carrier Proteins; Cartilage; Drug Synergism; Drug Therapy, Combination; Etanercept; Glycoproteins; Humans; Immunoglobulin G; Infliximab; Interleukin 1 Receptor Antagonist Protein; Interleukin-1; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sialoglycoproteins; Synovitis; Tumor Necrosis Factor-alpha

Topics: Arthritis, Rheumatoid; Carrier Proteins; Cells, Cultured; Fibroblasts; Glycoproteins; Humans; Knee Joint; Membrane Glycoproteins; Osteoarthritis, Knee; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synovial Membrane

To clarify the regulation of osteoprotegerin (OPG) expression in rheumatoid synovial fibroblasts by investigating the effect of tumor necrosis factor-alpha (TNF-alpha) and the mechanism of TNF-alpha-induced OPG expression.. OPG expression was examined by Northern blot hybridization and reverse transcriptase-polymerase chain reaction in synovial fibroblasts from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and subjects with no inflammatory condition. Amounts of OPG in conditioned medium were determined by ELISA. The effect of OPG on TNF-alpha-induced osteoclastogenesis was investigated in primary cultures of RA synovial cells.. OPG was highly expressed in RA synovial fibroblasts compared to OA and noninflammatory synovial fibroblasts. Different levels of OPG expression were found among patients with RA. TNF-alpha induced OPG expression in all synovial fibroblasts, even OA and noninflammatory fibroblasts, and expression occurred to a remarkable degree in RA fibroblasts. The OPG expression was upregulated by TNF-alpha in a time- and dose-dependent manner. TNF-alpha-induced OPG expression was inhibited by hymenialdisine, a nuclear factor-kappaB inhibitor, in a dose-dependent manner, and expression was inhibited by soluble TNF receptor/Fc fusion protein I (TNFs-RI/Fc), not by TNFs-RII/Fc. In contrast, TNF-alpha-induced osteoclastogenesis in primary cultures of RA synovial cells was inhibited by the addition of OPG.. These results suggest that OPG is highly expressed and is upregulated by TNF-alpha in rheumatoid synovial fibroblasts. TNF-alpha-induced OPG expression is mediated predominantly through TNF-RI. Although TNF-alpha is known to stimulate bone destruction, TNF-alpha-induced upregulation of OPG may contribute to self-protection from the bone destruction in RA.

Topics: Adult; Aged; Antigens, CD; Arthritis, Rheumatoid; Calcitriol; Carrier Proteins; Cells, Cultured; Female; Fibroblasts; Glycoproteins; Humans; Membrane Glycoproteins; Middle Aged; Osteoarthritis, Knee; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II; Synovial Membrane; Tumor Necrosis Factor-alpha

Topics: Arthritis, Rheumatoid; Glycoproteins; Humans; Immunologic Factors; Interferon-alpha; Interleukin 1 Receptor Antagonist Protein; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sialoglycoproteins; Synovial Membrane

Osteoclasts, specialised bone resorbing cells regulated by RANKL and M-CSF, are implicated in rheumatoid joint erosion. Lymphocyte-monocyte interactions activate bone resorption, this being attributed to tumour necrosis factor alpha (TNFalpha) and interleukin 1 beta (IL1beta) enhanced osteoblast expression of RANKL. In animal studies, TNF potently increases osteoclast formation in the presence of RANKL. RANKL-independent osteoclastogenesis also occurs, though IL1 is required for resorptive function in most studies. These inflammatory cytokines have a pivotal role in rheumatoid arthritis,. To study the interactions of TNFalpha and IL1beta with RANKL, particularly the time course of the interactions and the role of lymphocytes.. Cultures of lymphocytes and monocytes (osteoclast precursors) or of purified CD14(+) cells alone (osteoclast precursors) were exposed to various combinations of TNFalpha, RANKL, and IL1beta or the inhibitors osteoprotegerin, IL1 receptor antagonist, or neutralising antibodies to RANKL or to IL1. Osteoclastogenesis and resorptive activity were assessed on microscopy of dentine slices.. TNFalpha potently increased osteoclast proliferation/differentiation in the presence of RANKL. This effect was greatest when RANKL was present before but not after exposure of osteoclast precursor cells to TNFalpha. The resorptive activity of osteoclasts generated by TNFalpha in the absence of RANKL was critically dependent upon IL1, which was expressed by lymphocyte-monocyte interaction.. TNFalpha potently enhances RANKL mediated osteoclast activity. Interactions between TNFalpha and IL1 also result in osteoclastic activity independently of RANKL. These findings will inform therapeutic approaches to the prevention of joint erosion in rheumatoid arthritis.

Topics: Arthritis, Rheumatoid; Bone Resorption; Cell Division; Cells, Cultured; Flow Cytometry; Glycoproteins; Humans; Interleukin-1; Joints; Lipopolysaccharide Receptors; Lymphocytes; Osteoclasts; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Time Factors; Tumor Necrosis Factor-alpha

To determine the contribution of IL-1beta, tumor necrosis factor alpha (TNF-alpha) and IL-17 to AP-1, NF-kappaB and Egr-1 activation in rheumatoid arthritis, the effect of the cytokines used alone or in combination was measured on TF expression in rheumatoid synoviocytes. Effects on mRNA expression were measured by RT-PCR and effects on nuclear translocation were measured by immunocytochemistry. To assess the functional consequences of cytokine induction, osteoprotegerin levels were measured in synoviocyte supernatants.IL-1beta and TNF-alpha alone at optimal concentration (100 pg/ml) induced the nuclear translocation of NF-kappaB and almost all AP-1 members, except JunB and Egr-1 for IL-1beta and except Fra-2 and Egr-1 for TNF-alpha. IL-17 was clearly less potent since no nuclear translocation was observed, except for a weak activation of Fra-1 and NF-kappaB. More importantly, when these cytokines were used at low concentrations, their combination showed a synergistic effect on almost all the TFs, except for Egr-1, with a particular effect on Fra-1 and NF-kappaB. Increased recruitment of additional factors was induced when the three cytokines were combined. IL-1 and TNF-alpha induced mRNA expression of c-jun while IL-17 had no effect. A synergistic effect was seen with their combination. A similar synergistic effect was observed for osteoprotegerin production when these three cytokines were combined at low concentrations.AP-1 and NF-kappaB pathways were highly sensitive to the combination through synergistic mechanisms. These effects observed in rheumatoid arthritis synoviocytes may reflect the conditions found in the rheumatoid arthritis joint and may contribute to the mode of action of cytokine inhibitors.

Topics: Active Transport, Cell Nucleus; Arthritis, Rheumatoid; Cells, Cultured; DNA-Binding Proteins; Early Growth Response Protein 1; Glycoproteins; Humans; Immediate-Early Proteins; Inflammation; Interleukin-1; Interleukin-17; NF-kappa B; Osteoprotegerin; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Synovial Membrane; Transcription Factor AP-1; Transcription Factors; Tumor Necrosis Factor-alpha

We examined the role of osteoprotegerin (OPG) on tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in rheumatoid fibroblast-like synovial cells (FLS). OPG protein concentrations in synovial fluid from patients with rheumatoid arthritis (RA) correlated with those of interleukin (IL)-1beta or IL-6. A similar correlation was present between IL-1beta and IL-6 concentrations. Rheumatoid FLS in vitro expressed both death domain-containing receptors [death receptor 4 (DR4) and DR5] and decoy receptors [decoy receptor 1 (DcR1) and DcR2]. DR4 expression on FLS was weak compared with the expression of DR5, DcR1 and DcR2. Recombinant TRAIL (rTRAIL) rapidly induced apoptosis of FLS. DR5 as well as DR4 were functional with regard to TRAIL-mediated apoptosis induction in FLS; however, DR5 appeared be more efficient than DR4. In addition to soluble DR5 (sDR5) and sDR4, OPG administration significantly inhibited TRAIL-induced apoptogenic activity. OPG was identified in the culture supernatants of FLS, and its concentration increased significantly by the addition of IL-1beta in a time-dependent manner. Neither IL-6 nor tumour necrosis factor (TNF)-alpha increased the production of OPG from FLS. TRAIL-induced apoptogenic activity towards FLS was reduced when rTRAIL was added without exchanging the culture media, and this was particularly noticeable in the IL-1beta-stimulated FLS culture; however, the sensitivity of FLS to TRAIL-induced apoptosis itself was not changed by IL-1beta. Interestingly, neutralization of endogenous OPG by adding anti-OPG monoclonal antibody (MoAb) to FLS culture restored TRAIL-mediated apoptosis. Our data demonstrate that OPG is an endogenous decoy receptor for TRAIL-induced apoptosis of FLS. In addition, IL-1beta seems to promote the growth of rheumatoid synovial tissues through stimulation of OPG production, which interferes with TRAIL death signals in a competitive manner.

Topics: Antibodies, Monoclonal; Apoptosis; Arthritis, Rheumatoid; Cells, Cultured; Fibroblasts; Glycoproteins; Humans; Interleukin-1; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor; Synovial Fluid; Tumor Necrosis Factor-alpha

To further understand the role of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANK-L) in rheumatoid arthritis (RA), we studied the levels of RANK-L and OPG mRNA in peripheral blood mononuclear cells (PBMC) and synovial tissue of patients with RA and controls.. RANK-L and OPG mRNA levels were measured in PBMC and CD4+/CD8+ T cell subsets of patients with chronic RA, osteoarthritis (OA), and healthy controls, using quantitative real-time polymerase chain reaction. OPG and RANK-L mRNA levels were measured in paired blood and synovial tissue samples of patients with early, untreated RA at 2 timepoints with an interval of 16 weeks.. RANK-L mRNA levels were significantly higher in PBMC of patients with early and chronic RA compared to healthy controls. Contrary to healthy controls, RANK-L mRNA levels in patients with chronic RA were mainly of CD4+ T cell origin. OPG mRNA was observed in the blood of all (17/17) early RA patients, but could not be detected in chronic RA patients (0/14) or in patients with OA (0/8). Three out of 17 healthy controls showed measurable levels of OPG mRNA. The OPG/RANK-L ratio tended to be higher in the synovium than in the PBMC of early RA patients. RANK-L mRNA in synovial tissue was mainly of non-T cell origin.. Since RANK-L and OPG mRNA levels are elevated in PBMC of RA patients, and CD4+ T cells are the major contributors to RANK-L mRNA expression, mononuclear cells in patients with RA may be involved in the pathways that regulate bone metabolism.

Topics: Adult; Aged; Arthritis, Rheumatoid; Carrier Proteins; Case-Control Studies; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Female; Glycoproteins; Humans; Lymphocyte Activation; Male; Membrane Glycoproteins; Middle Aged; Monocytes; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Synovial Membrane

Topics: Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Glycoproteins; Humans; Membrane Glycoproteins; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Synovial Membrane; T-Lymphocyte Subsets

To determine whether IL18 has any indirect effects on osteoclastogenesis mediated by T cells in RA synovium, and compare its effects with those of IL1 beta and TNF alpha.. Resting T cells were isolated from peripheral blood of healthy donors, and stimulated with 2 microg/ml phytohaemagglutinin (PHA) and 0.5 ng/ml IL2 for 24 hours. Synovial T cells were isolated from RA synovial tissue. The levels of soluble receptor activator of the NF-kappa B ligand (RANKL), osteoprotegerin (OPG), IFN gamma, M-CSF, and GM-CSF were determined by ELISA. Membrane bound RANKL expression was analysed by flow cytometry. Commercially available human osteoclast precursors were cocultured with T cells to induce osteoclast formation, which was determined with tartrate resistant acid phosphatase staining and pit formation assay.. In PHA prestimulated T cells or RA synovial T cells, IL18, IL1 beta, or TNFalpha increased soluble RANKL production and membrane bound RANKL expression in a dose dependent manner. IL18, IL1 beta, and TNF alpha did not induce M-CSF, GM-CSF, IFN gamma, or OPG production in PHA prestimulated T cells or RA synovial T cells. IL18 increased the number of osteoclasts and bone resorption area on dentine slices in the coculture of human osteoclast precursors with PHA prestimulated T cells or RA synovial T cells; its ability was equivalent to that of IL1 beta, but less potent than that of TNF alpha. In the coculture system, OPG completely blocked osteoclast induction by IL18 or IL1 beta, and greatly inhibited induction by TNF alpha.. IL18, IL1 beta, or TNF alpha can indirectly stimulate osteoclast formation through up regulation of RANKL production from T cells in RA synovitis; IL18 is as effective as IL1 beta, but less potent than TNF alpha.

Topics: Analysis of Variance; Arthritis, Rheumatoid; Bone Resorption; Carrier Proteins; Cells, Cultured; Flow Cytometry; Glycoproteins; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Interferon-gamma; Interleukin-1; Interleukin-18; Lymphocyte Activation; Macrophage Colony-Stimulating Factor; Membrane Glycoproteins; Mitogens; Osteoclasts; Osteoprotegerin; Phytohemagglutinins; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Synovial Membrane; T-Lymphocytes; Tumor Necrosis Factor-alpha

To demonstrate the effects of disease-modifying antirheumatic drugs and antiinflammatory cytokines on human osteoclastogenesis through their effects on receptor activator of nuclear factor kappaB (RANK), osteoprotegerin (OPG), and RANK ligand (RANKL).. Peripheral blood mononuclear cells (PBMCs) and rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) were cocultured in the presence of macrophage colony-stimulating factor, 1,25-dihydroxyvitamin D(3), and various concentrations of methotrexate (MTX), sulfasalazine (SSZ), hydroxychloroquine (HCQ), anti-tumor necrosis factor alpha monoclonal antibody (infliximab), interleukin-4 (IL-4), and IL-10. Osteoclast formation was assayed by counting cells after staining for tartrate-resistant acid phosphatase. RANKL expression in RA FLS and RANK expression in PBMCs were assayed by Western blotting, reverse transcription-polymerase chain reaction (RT-PCR), and real-time PCR. OPG expression was measured by enzyme-linked immunosorbent assay, RT-PCR, and real-time PCR in cultures of RA FLS.. MTX, SSZ, infliximab, and IL-4, but not IL-10 and HCQ, each inhibited osteoclast formation in a dose-dependent manner. We observed no evidence of synergistic inhibition of osteoclast formation by IL-4 and IL-10. High doses of infliximab suppressed the expression of RANK in PBMCs. MTX, SSZ, infliximab, and IL-4 each inhibited the expression of RANKL in RA FLS in a dose-dependent manner, and also increased the secretion of OPG in RA FLS supernatants.. MTX, SSZ, infliximab, and IL-4 inhibit human osteoclastogenesis by modulating the interaction of RANKL, RANK, and OPG. These results are indicative of the underlying mechanisms of the antiresorptive effects of these 4 agents.

Topics: Acid Phosphatase; Antirheumatic Agents; Arthritis, Rheumatoid; Blotting, Western; Carrier Proteins; Cell Survival; Coculture Techniques; Cytokines; Dose-Response Relationship, Drug; Fibroblasts; Glycoproteins; Humans; Isoenzymes; Leukocytes, Mononuclear; Membrane Glycoproteins; Osteoclasts; Osteogenesis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synovial Membrane; Tartrate-Resistant Acid Phosphatase

To demonstrate the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB ligand (RANKL) in synovial tissue from rheumatoid arthritis (RA) patients, establish the cell lineage expressing OPG and compare the expression of OPG in RA, spondyloarthropathies, osteoarthritis and normal synovial tissue.. Synovial biopsy specimens were obtained at arthroscopy from 16 RA and 12 spondyloarthropathy patients with active synovitis of a knee joint, six RA patients with no evidence of active synovitis, 10 patients with osteoarthritis and 18 normal subjects. Immunohistological analysis was performed using monoclonal antibodies (mAb) to detect OPG and RANKL expression. In addition, dual immunohistochemical evaluation was performed with lineage-specific monoclonal antibodies (macrophages, fibroblasts and endothelial cells) and OPG to determine the cell lineages expressing OPG. The sections were evaluated by computer-assisted image analysis and semiquantitative analysis.. Two patterns of OPG expression were seen, one exclusively in endothelial cells and one expressed predominantly in macrophages in the synovial lining layer. Both patterns of OPG staining could be blocked with excess recombinant OPG. Endothelial and synovial lining expression of OPG was seen in all synovial tissues except those from patients with active RA. In contrast, RANKL expression was seen predominantly in synovial tissue from patients with active disease, mainly in sublining regions, particularly within areas of lymphocyte infiltration.. OPG expression on macrophage type synovial lining cells as well as endothelial cells is deficient in RA patients with active synovitis, in contrast to that seen in spondyloarthropathy patients with active synovitis. This deficiency in OPG expression in the inflamed joint of RA patients may be important in the development of radiologically defined joint erosions.

Topics: Acute Disease; Adult; Aged; Arthritis; Arthritis, Rheumatoid; Arthroscopy; Blotting, Western; Carrier Proteins; Case-Control Studies; Endothelium; Female; Glycoproteins; Humans; Image Processing, Computer-Assisted; Immunohistochemistry; Knee Joint; Macrophages; Male; Membrane Glycoproteins; Middle Aged; Osteoarthritis, Knee; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Spondylarthropathies; Statistics, Nonparametric; Synovial Membrane

To evaluate the therapeutic potential of interferon-a (IFN-a) in osteoarthritis (OA) and rheumatoid arthritis (RA) by examining regulation of cytokine antagonist expression.. Expression of interleukin 1 receptor antagonist (IL-1Ra) and soluble tumor necrosis factor receptor (sTNFR) was examined by ELISA in cells from freshly isolated synovial fluids (SF) and synovial tissues (ST) from patients with OA or RA, either left untreated or treated with IFN-a. Single (7) and paired (5) SF and ST cells from OA and RA patients were examined. As well, the ability of IFN-a to regulate gene expression levels for osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) was examined in freshly isolated SF cells from patients with RA, by reverse transcriptase polymerase chain reaction.. IL-1Ra and sTNFR were found to be constitutively expressed in OA and RA SF and ST cells. IFN-a treatment resulted in an increase in both IL 1Ra and sTNFR production. Freshly isolated RA SF cells exhibited constitutive OPGL gene expression in both the non-T and T cell fractions of the SF. In contrast, OPG gene expression levels were undetectable or low. IFN-a treatment of RA SF cells resulted in upregulation of OPG gene expression in the T cell fraction of the RA SF cells, whereas OPGL gene expression remained unaffected.. These in vitro data suggest a therapeutic role for IFN-a in the treatment of arthritis through upregulation of critical cytokine antagonists.

Topics: Adult; Arthritis, Rheumatoid; Carrier Proteins; Etanercept; Gene Expression; Glycoproteins; Humans; Immunoglobulin G; Immunologic Factors; In Vitro Techniques; Interferon-alpha; Interleukin 1 Receptor Antagonist Protein; Membrane Glycoproteins; Osteoarthritis; Osteoprotegerin; Pilot Projects; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sialoglycoproteins; Synovial Fluid; Synovial Membrane; Up-Regulation

To investigate the role of tumor necrosis factor (TNF) in systemic bone loss of chronic inflammatory conditions, such as rheumatoid arthritis (RA), and to address the therapeutic potential of osteoclast blockade.. We investigated systemic bone changes in human TNF transgenic (hTNFtg) mice, which spontaneously developed severe inflammatory arthritis.. Osteodensitometry revealed a significant decrease in trabecular bone mineral density (BMD) (-37%) in hTNFtg mice, and histomorphometry revealed a dramatic loss of bone volume (-85%) compared with wild-type controls. Osteoclast-covered bone surface and serum levels of deoxypyridinoline crosslinks were significantly elevated, suggesting increased osteoclast-mediated bone resorption in hTNFtg mice. Osteoprotegerin (OPG) completely blocked TNF-mediated bone loss by increasing BMD (+89%) and bone volume (+647%). Most strikingly, formation of primary spongiosa was dramatically increased (+563%) in hTNFtg mice after OPG treatment. Osteoclast-covered bone surface and serum levels of deoxypyridinoline crosslinks were significantly decreased by OPG, suggesting effective blockade of osteoclast-mediated bone resorption. OPG did not influence levels of hTNF, TNF receptor I (TNFRI), interleukin-1beta (IL-1beta), and IL-6. However, OPG decreased bone formation parameters (osteoblast-covered bone surface and serum osteocalcin levels), which were elevated in hTNFtg mice. In contrast to OPG, bisphosphonates and anti-TNF treatment did not affect generalized bone loss in hTNFtg mice. Anti-TNF, however, did not affect levels of TNF and TNFRI at the concentrations tested. These data indicate that generalized bone loss due to increased TNF can be blocked by OPG.. OPG may represent a potent tool for preventing generalized loss of bone mass in chronic inflammatory disorders, especially RA.

Topics: Animals; Arthritis, Rheumatoid; Bone Density; Bone Resorption; Chronic Disease; Glycoproteins; Mice; Mice, Transgenic; Osteoclasts; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tumor Necrosis Factor-alpha

A recent Italian study found that homozygosity for the G allele of the +196 single nucleotide polymorphism (SNP) of the tumor necrosis factor receptor II (TNFRSF1B) gene was more prevalent in patients with severe rheumatoid arthritis (RA). We investigated whether this particular SNP, and also one at position +36 in exon 1 of the TNF receptor I (TNFRSF1A) gene, are associated with disease severity.. A group of 181 Caucasian patients with RA was studied. DNA was isolated from patient blood samples and subsequently used to genotype both the exon 1 TNFRSF1A SNP and the exon 6 TNFRSF1B SNP by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. Radiographic damage was measured by the Larsen score, and functional outcome was assessed by the Health Assessment Questionnaire (HAQ). Data were analyzed by multiple regression analysis, with correction for age, sex, and disease duration.. The mean Larsen and HAQ scores did not differ significantly between each of the genotypes from the 2 TNFR SNP. No significant associations between the +36 TNFRSF1A SNP or the +196 TNFRSF1B SNP genotypes and disease severity were found after correcting for age, sex, and disease duration.. Our data suggest that neither the +36 TNFRSF1A SNP nor the +196 TNFRSF1B SNP is associated with RA severity in a population of Caucasian patients with RA.

Topics: Antigens, CD; Arthritis, Rheumatoid; Disability Evaluation; DNA; Female; Genotype; Glycoproteins; Health Status; Humans; Male; Middle Aged; Osteoprotegerin; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Polymorphism, Single Nucleotide; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II; Severity of Illness Index

To assess the interpatient, interbiopsy, and intrabiopsy variability of receptor activator of nuclear factor kB ligand (RANKL) and osteoprotegerin (OPG) immunostaining within synovial tissue from rheumatoid knee joints with active synovitis, using digital image analysis.. Synovial biopsy specimens were obtained from patients with rheumatoid arthritis (RA) and active synovitis. Immunohistologic analysis was performed on frozen synovial tissue biopsy specimens from 6 patients using a monoclonal antibody (Mab) to detect RANKL (626) or OPG (805 or 8051). Patients with a minimum of 4 synovial biopsies were included in the study. Sections were evaluated by computer assisted image analysis to assess between-patient, between-biopsy, and intra-biopsy variability of OPG and RANKL protein expression. The study was designed to deliberately maximize the variability.. Computerized image analysis of staining with Mab to RANKL and OPG revealed variance for each antibody across the 3 components of the total variability.. Our study shows that variability in synovial immunostaining of RANKL and OPG protein is a significant and complex problem. We discuss methods to reduce this variability and suggest that the auspices of OMERACT may be employed to advance the study of synovium in collaborative international studies.

Topics: Aged; Antibodies, Monoclonal; Arthritis, Rheumatoid; Carrier Proteins; Color; Female; Glycoproteins; Humans; Image Processing, Computer-Assisted; Immunohistochemistry; Male; Membrane Glycoproteins; Middle Aged; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Staining and Labeling; Synovial Membrane

To test the hypotheses that 1) proinflammatory cytokines affect osteoprotegerin (OPG) and soluble receptor activator of nuclear factor kappa B ligand (sRANKL) production and therefore the OPG and sRANKL levels differ in rheumatoid arthritis (RA) patients in comparison with healthy individuals; and 2) anti-tumor necrosis factor alpha (anti-TNF alpha) therapy influences OPG and sRANKL levels.. Sera were obtained from healthy individuals or RA patients receiving the combination of infliximab and methotrexate. Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were isolated from RA patients. Fibroblast-like synoviocytes (FLS) were isolated from synovial tissue obtained at total knee replacement in RA patients. Supernatants from cells stimulated with cytokines were collected after culture in vitro. Concentrations of OPG and sRANKL were determined by enzyme-linked immunosorbent assays.. A strong positive correlation between OPG concentration and age was observed in healthy individuals but not in RA patients. The OPG and sRANKL levels were higher in RA patients than in healthy controls. Cultured FLS spontaneously secreted much higher amounts of OPG than PBMCs or SFMCs. Proinflammatory cytokines enhanced OPG production. Anti-TNF alpha treatment resulted in the normalization of serum OPG and sRANKL levels in RA patients without influencing the OPG:sRANKL ratio.. Although higher serum levels of OPG and sRANKL are present in RA patients than in healthy individuals, the ratio of OPG:sRANKL is similar. There is an age-dependent increase of OPG but not sRANKL levels in healthy subjects. Anti-TNF alpha treatment results in the normalization of elevated levels of OPG and sRANKL in RA patients.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Antibodies, Monoclonal; Antirheumatic Agents; Arthritis, Rheumatoid; Enzyme-Linked Immunosorbent Assay; Glycoproteins; Humans; Infliximab; Methotrexate; Middle Aged; Neoplasm Proteins; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type II; Synovial Fluid; Tumor Necrosis Factor Decoy Receptors

To compare receptor activator of NF-kappaB ligand (RANKL) production in the synovial tissue from patients with active rheumatoid arthritis (RA), inactive RA, spondyloarthropathies (SpA), osteoarthritis, and from normal subjects. In addition, to establish the cell lineages expressing RANKL in these tissues.. Immunohistological analysis of frozen synovial tissue biopsy specimens was performed using a monoclonal antibody (mAb) to detect RANKL. Sections were evaluated by computer assisted image analysis and semiquantitative analysis to compare RANKL expression between groups. Dual and sequential labelling with mAb RANKL and cell lineage specific monoclonal antibodies were used to determine the types of cells expressing RANKL.. Higher levels of RANKL were expressed in tissues from patients with active RA and SpA than in tissues from patients with inactive RA, osteoarthritis, and from normal subjects. RANKL protein was associated with CD3 antigen-positive lymphocytes and some macrophages. RANKL was predominantly associated with activated, memory T cells (CD45Ro positive cells) in patients with active RA and spondyloarthropathy (SpA).. The highest levels of RANKL were detected in patients with RA with active synovitis and in some patients with SpA. An increase in RANKL in the inflamed joint of patients with RA, produced by infiltrating activated T cells and macrophages, is likely to be an important cause of joint erosions in RA.

Topics: Adult; Aged; Arthritis, Rheumatoid; CD3 Complex; Female; Glycoproteins; Humans; Immunoenzyme Techniques; Leukocytes, Mononuclear; Lymphocytes; Macrophages; Male; Middle Aged; Osteoarthritis; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Spondylarthropathies; Synovial Fluid

To elucidate the direct role of human T cells in the induction of osteoclastogenesis in rheumatoid arthritis (RA), by studying human monocytes and the pathogenetic roles of receptor activator of nuclear factor kappaB ligand (RANKL), RANK, and osteoprotegerin (OPG).. Synovial tissue obtained at total knee replacement was stained immunohistologically using anti-RANKL, CD3, and CD4 antibodies. Synovial fluid was obtained from patients with RA, osteoarthritis (OA), gout, or trauma. Concentrations of the soluble form of RANKL (sRANKL) and OPG in the synovial fluid were measured by enzyme-linked immunosorbent assay. Activated T cells from peripheral blood mononuclear cells (PBMC) of healthy volunteers were cultured with human monocytes from PBMC.. Immunostaining of the synovial tissue of RA patients demonstrated that RANKL-positive cells were detected in a subset of fibroblast-like synoviocytes and infiltrating mononuclear cells. Double immunostaining revealed that RANKL-positive cells were detected in a subset of CD3+ cells and CD4+ cells. An increased concentration of sRANKL and a decreased concentration of OPG were detected in synovial fluid from RA patients. The ratio of the concentration of sRANKL to that of OPG was significantly higher in synovial fluid of RA patients than in synovial fluid of patients with OA or gout. The activated T cells expressing RANKL induced osteoclastogenesis from autologous peripheral monocytes. The role of RANKL in this osteoclastogenetic process was confirmed by dose-dependent inhibition by OPG.. The present study is the first to demonstrate osteoclastogenesis using human-derived T cells and monocytes. In addition, the present findings suggest that excess production of RANKL by activated T cells increases the level of sRANKL in synovial fluid and may contribute to osteoclastic bone resorption in RA patients.

Topics: Antibodies; Arthritis, Rheumatoid; Carrier Proteins; CD3 Complex; CD4 Antigens; CD4-Positive T-Lymphocytes; Coculture Techniques; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression; Glycoproteins; Gout; Humans; In Situ Hybridization; Lymphocyte Activation; Male; Membrane Glycoproteins; Monocytes; Osteoarthritis; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Synovial Fluid

Topics: Arthritis, Rheumatoid; Bone Density; Carrier Proteins; Cytokines; Glycoproteins; Humans; Membrane Glycoproteins; Osteoblasts; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

This study investigated the involvement of the recently identified regulators of osteoclast formation RANKL [receptor activator of nuclear factor kappaB (RANK) ligand, osteoclast differentiation factor, TRANCE, osteoprotegerin ligand] and its natural inhibitor, osteoprotegerin (OPG), in the bone erosion of rheumatoid arthritis (RA).. mRNA was extracted from cells isolated from the pannus and synovial membrane regions of joints of 11 RA patients. Semiquantitative reverse transcription-polymerase chain reaction was carried out, and the isolated cells were also cultured to determine their ability to form osteoclasts.. mRNAs encoding RANKL, RANK, OPG and macrophage-colony stimulating factor were expressed by cells isolated from RA joints. In addition, mRNA encoding for tumour necrosis factor apoptosis-inducing ligand and the osteoclast markers tartrate-resistant acid phosphatase and calcitonin receptor were also often expressed. Osteoclasts capable of forming resorption lacunae were generated from cells in the RA joints. At 50 ng/ml, recombinant OPG completely inhibited the resorptive activity of these cells. There was a significant correlation between the ratio of RANKL mRNA to OPG mRNA and the number of resorption pits produced (P = 0.028).. These data suggest that RANKL is an essential factor for osteoclast formation by cells in the rheumatic joint and that OPG may prevent the bone erosion seen in RA joints.

Topics: Adult; Aged; Arthritis, Rheumatoid; Carrier Proteins; Female; Glycoproteins; Humans; Male; Membrane Glycoproteins; Middle Aged; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Rheumatic diseases are often associated with changes in bone metabolism. Excessive production and release of cytokines and other growth factors due to inflammation, e.g. tumor necrosis factor-alpha (TNF-alpha), receptor activator of NF-kappaB ligand (RANKL), interleukins such as IL-1 and IL-6, may cause alterations in bone homeostasis leading to bone degradation. Other components such as osteoprotegerin (OPG) and possibly the ligand-receptor pair hepatocyte growth factor (HGF) and c-met may counteract this destruction, we have measured the levels of OPG, and HGF c-met, in serum, synovial fluid (SF), and cartilage from patients with rheumatoid arthritis (RA) and other arthritides. We found a) elevated levels of both OPG and HGF in SF from RA patients relative to arthritides of other causes, b) increased levels of both OPG and HGF in SF from seropositive RA patients (RA+) compared to seronegative RA patients (RA-), c) elevated levels or both OPG and HGF in serum from RA patients compared to healthy controls, d) no correlation between severity of inflammation and levels of OPG or HGF, and e) presence of HGF c-met in both cartilage and synovial tissue. The most significant elevations of OPG and HGF were found in patients with RA, the rheumatic disease most frequently associated with the development of secondary osteoporosis.

Topics: Adult; Arthritis, Rheumatoid; Cartilage, Articular; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique, Indirect; Glycoproteins; Hepatocyte Growth Factor; Humans; Male; Middle Aged; Osteoarthritis; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Spondylitis, Ankylosing; Synovial Fluid

To understand the involvement of osteoclastogenesis inhibitory factor (OCIF), also called osteoprotegerin (OPG), in the pathogenesis of bone destruction in rheumatoid arthritis (RA), we investigated the cytokine network involved in the production of OCIF by human fibroblast-like synovial (HFLS) cells from a patient with RA. Inflammatory cytokines, such as interleukin (IL)-1beta, IL-6 plus soluble IL-6 receptor (sIL-6R), IL-17, and tumor necrosis factor (TNF)-alpha, which are elevated in synovial fluid in RA, upregulated the production of OCIF to a level (5-20 ng/ml) sufficient to inhibit osteoclastogenesis in vitro. These inflammatory cytokines (except for IL-6 plus sIL-6R) stimulate OCIF production directly or indirectly through stimulation of prostaglandin E2 (PGE2) synthesis. In contrast to the findings with inflammatory cytokines, basic fibroblast growth factor (bFGF) inhibited the production of OCIF by the cells in a dose-dependent manner. While bFGF enhanced both the inflammatory cytokine-mediated release of PGE2 and the PGE2-mediated OCIF production, it significantly suppressed OCIF production by negating the direct stimulatory effect of the inflammatory cytokines. These findings suggest that bFGF in the synovial fluid of patients with RA may lead to severe joint destruction by suppressing the production of OCIF by HFLS cells.

Topics: Arthritis, Rheumatoid; Bone Resorption; Cells, Cultured; Culture Media, Conditioned; Dinoprostone; Fibroblast Growth Factor 2; Gene Expression Regulation; Glycoproteins; Humans; Interleukin-1; Nitrobenzenes; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sulfonamides; Synovial Membrane

To clarify the mechanism by which osteoclasts are formed in culture of rheumatoid synoviocytes by exploring the involvement of receptor activator of nuclear factor kappaB ligand (RANKL)/osteoclast differentiation factor (ODF).. Osteoclast formation was evaluated in cocultures of rheumatoid synovial fibroblasts and peripheral blood mononuclear cells (PBMC) in the presence of macrophage colony stimulating factor and 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) utilizing separating membrane filters. RANKL/ODF expression was examined by Northern blotting in synovial tissues from 5 rheumatoid arthritis (RA) patients and tissues from patients with giant cell tumor (GCT), osteosarcoma (OS), and osteoarthritis (OA). RANKL/ODF expression and the ability of synovial fibroblasts to support osteoclastogenesis were investigated in coculture with PBMC in the presence or absence of 1,25(OH)2D3, and soluble RANKL/ODF and osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF) were measured by enzyme-linked immunosorbent assay. The effects of OPG/OCIF on the osteoclastogenesis in the primary culture of rheumatoid synoviocytes and the coculture system were determined.. Synovial fibroblasts did not induce osteoclastogenesis when separately cocultured with PBMC. Northern blotting revealed that RANKL/ODF was highly expressed in all tissues from RA and GCT patients, but not from OA or OS patients. Cultured rheumatoid synovial fibroblasts efficiently induced osteoclastogenesis in the presence of 1,25(OH)2D3, which was accompanied by up-regulated expression of RANKL/ODF and decreased production of OPG/OCIF. Osteoclastogenesis from synoviocytes was dose-dependently inhibited by OPG/OCIF.. RANKL/ODF expressed on synovial fibroblasts is involved in rheumatoid bone destruction by inducing osteoclastogenesis and would therefore be a good therapeutic target.

Topics: Arthritis, Rheumatoid; Blotting, Northern; Carrier Proteins; Cell Communication; Coculture Techniques; Fibroblasts; Fluorescent Antibody Technique; Glycoproteins; Humans; Membrane Glycoproteins; Osteoclasts; Osteogenesis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Synovial Membrane