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Article Chronic arthritis directly induces quantitative and qualitative bone disturbances leading to compromised biomechanical properties. 2009
Caetano-Lopes J, Henriques R, Canhão H, Duarte J, Amaral PM, Vale M, Moura RA, Pereira PA, Weinmann P, Abdulghani S, Souto-Carneiro M, Rego P, Monteiro J, Sakagushi S, Queiroz MV, Konttinen YT, Graça L, Vaz MF, Fonseca JE. · Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal. · Clin Exp Rheumatol. · Pubmed #19604441 No free full text.
Abstract: OBJECTIVES:Rheumatoid arthritis (RA) is associated with an increased risk of fragility fractures. In RA patients, the direct effect of inflammation on bone is difficult to study because their skeleton is also affected by medication with corticosteroids and other drugs as well as aging and menopause, which contribute to bone fragility. This study used an animal model of chronic arthritis to evaluate the direct impact of chronic inflammation on biomechanical properties and structure of bone.METHODS:In the SKG mouse chronic arthritis model three point bending tests were performed on femoral bones and compression tests on vertebral bodies. Collagen structure was analysed using second-harmonic generation (SHG) imaging with a two-photon microscope, ultramorphology by scanning electron microscopy (SEM) coupled with energy dispersive x-ray spectroscopy (EDS) and bone density using water pycnometer.RESULTS:Arthritic bones had poor biomechanical quality compared to control bones. SHG, SEM and pycnometry disclosed variable signs of impaired collagen organization, poor trabecular architecture and low bone density.CONCLUSION:Present data demonstrate for the first time that chronic inflammation per se, without confounding influence of drugs and aging, leads to impairment of bone biomechanics in terms of stiffness, ductility and ultimate strength (fracture).
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Article Delayed neutrophil apoptosis in very early rheumatoid arthritis patients is abrogated by methotrexate therapy. 2007
Weinmann P, Moura RA, Caetano-Lopes JR, Pereira PA, Canhão H, Queiroz MV, Fonseca JE. · Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal. · Clin Exp Rheumatol. · Pubmed #18173925 No free full text.
Abstract: OBJECTIVES: To analyse the activation state and apoptosis of circulating neutrophils in untreated very early rheumatoid arthritis (VERA) and after exposure to low dose corticosteroids and methotrexate (MTX). METHODS: Neutrophils were isolated from the peripheral blood of VERA patients at 3 different times: before any treatment was started, 2 weeks after starting a low dose of prednisone (5-10 mg) and 4 months after reaching more than 20mg/week of MTX. The expression of different activation markers (CD11b, CD64, CD86 and CD69) in freshly isolated neutrophils was analysed by flow cytometry. Apoptosis was measured by the loss of DNA content, which was analysed by flow cytometry using propidium iodide. RESULTS: Compared to neutrophils from healthy controls, we have found a delayed neutrophil apoptosis within 6 h and 22 h of cultured polymorphonuclear leukocytes (PMN) derived from VERA patients without any treatment or treated with corticosteroids. The delay of PMN apoptosis was restored to control levels after treatment with MTX. CONCLUSION: The treatment of VERA patients with corticosteroids did not affect the delay of neutrophil apoptosis. However, delayed apoptosis was restored to control levels after treatment with low dose MTX, which highlights the importance of early RA treatment with MTX.
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