Rheumatoid Arthritis: Gomez R

Otero M, Lago R, Gomez R, Dieguez C, Lago F, Gómez-Reino J, Gualillo O. · Santiago University Clinical Hospital, Research Laboratory 4 (NEIRID LAB, Laboratory of Neuro Endocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago de Compostela, Spain. · Rheumatology (Oxford). · Pubmed #16720637 links to  free full text

Abstract: Leptin is a 16 kDa adipocyte-secreted hormone that regulates weight centrally and links nutritional status with neuroendocrine and immune function. Since its cloning in 1994, leptin's role in regulating immune and inflammatory response has become increasingly evident. Actually, the increase of leptin production that occurs during infection and inflammation strongly suggests that leptin is a part of the cytokines loop which governs the inflammatory-immune response and the host defence mechanism. Indeed, leptin stimulates the production of pro-inflammatory cytokines from cultured monocytes and enhances the production of Th1 type cytokines from stimulated lymphocytes. Several studies have implicated leptin in the pathogenesis of autoimmune inflammatory conditions such as type 1 diabetes, rheumatoid arthritis and chronic bowel disease. Obesity is characterized by elevated circulating leptin levels which might contribute significantly to the so called low-grade systemic inflammation, making obese individuals more susceptible to the increased risk of developing cardiovascular diseases, type II diabetes or inflammatory articular degenerative disease such as osteorathritis (OA). As a matter of fact, a key role for leptin in OA has been recently demonstrated since leptin exhibits, in synergy with other pro-inflammatory cytokines, a detrimental effect on articular cartilage cells by promoting nitric oxide synthesis. This review will focus prevalently on the complex relationships existing among leptin, inflammatory response and immunity, trying to provide surprising insights into leptin's role and to discuss challenges and prospects for the future.

Lago R, Gomez R, Otero M, Lago F, Gallego R, Dieguez C, Gomez-Reino JJ, Gualillo O. · Santiago University Clinical Hospital, Research Laboratory 4, NeuroEndocrine Interactions in Rheumatology and Inflammatory Diseases Laboratory, Santiago de Compostela, Spain. · Osteoarthritis Cartilage. · Pubmed #18261936 No free full text.

Abstract: OBJECTIVE: Recent studies revealed a close connection between adipose tissue, adipokines and articular degenerative inflammatory diseases such as rheumatoid arthritis (RA) and osteoarthritis (OA). The goal of this work was to investigate the activity of adiponectin in human and murine chondrocytes and to study its functional role in the modulation of nitric oxide synthase type II (NOS2). For completeness, interleukin (IL)-6, IL-1beta, matrix metalloproteinase (MMP)-2, MMP-3, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, prostaglandin E2 (PGE2), leukotriene B4 (LTB4), tumor necrosis factor alpha (TNF)-alpha and monocyte chemoattractant protein-1 (MCP-1) accumulation have been evaluated in adiponectin-stimulated chondrocytes cell culture supernatants. METHODS: Murine ATDC5 cell line, C28/I2, C20A4, TC28a2 human immortalized chondrocytes, and human cultured chondrocytes were used. Nitrite accumulation was determined by Griess reaction. Adiponectin receptors (AdipoRs) expression was evaluated by immunofluorescence microscopy and confirmed by reverse transcriptase-polymerase chain reaction. NOS2 expression was evaluated by Western blot analysis whereas cytokines, prostanoids and metalloproteinases production was evaluated by specific enzyme-linked immunosorbent assays. RESULTS: Human and murine chondrocytes express functional AdipoRs. Adiponectin induces NOS2. This effect is inhibited by aminoguanidine, dexamethasone and by a selective inhibitor of phosphatidylinositol 3-kinase. In addition, adiponectin is able to increase IL-6, MMP-3, MMP-9 and MCP-1 by murine cultured chondrocytes whereas it was unable to modulate TNF-alpha, IL-1beta, MMP-2, TIMP-1, PGE2 and LTB4 release. CONCLUSIONS: These results bind more closely the interactions between fat-derived adipokines and articular inflammatory diseases, and suggest that adiponectin is a novel key element in the maintenance of cartilage homeostasis which might be considered as a potential therapeutical target in joint degenerative diseases.

Otero M, Lago R, Gomez R, Lago F, Dieguez C, Gómez-Reino JJ, Gualillo O. · NEIRID (NeuroEndocrine Interactions in Rheumatology and Inflammatory Diseases) Laboratory, Santiago University Clinical Hospital, Spain. · Ann Rheum Dis. · Pubmed #16414972 No free full text.

Abstract: BACKGROUND: Rheumatoid arthritis is a chronic autoimmune inflammatory condition characterised by polyarthritis and severe change in body mass and neuroendocrine environment. OBJECTIVES: To investigate plasma levels of adipocytokines (leptin, adiponectin, visfatin and resistin) in patients with rheumatoid arthritis and to compare them with levels in healthy controls. METHODS: Adiponectin, resistin, visfatin and leptin concentrations were measured in 31 patients with rheumatoid arthritis and 18 healthy controls by using specific enzyme-linked immunosorbent assays. RESULTS: Patients with rheumatoid arthritis showed considerably higher plasma levels of leptin, adiponectin and visfatin than healthy controls. No marked difference was observed in resistin levels between patients and controls. CONCLUSION: A marked increase in plasma levels of leptin, adiponectin and visfatin was noted in patients with rheumatoid arthritis, whereas resistin levels were similar to those observed in healthy controls. Coordinated roles for adiponectin, leptin and visfatin are suggested in the modulation of the inflammatory environment in patients with rheumatoid arthritis, whereas the lack of modulation in resistin levels is predictive of an irrelevant role for this peptide, suggesting that resistin level is probably not one of the main signals associated with the pathogenesis of this disease.