Rheumatoid Arthritis: Caetano-Lopes J

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).

Abdulghani S, Caetano-Lopes J, Canhão H, Fonseca JE. · Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal. · Autoimmun Rev. · Pubmed #19223022 No free full text.

Abstract: Inflammatory diseases, such as rheumatoid arthritis (RA), influence the bone remodelling process and increase the risk of fracture. Bone can be viewed as a composite material comprising of two phases: the organic phase, constituted predominantly by collagen type I, and the mineral phase, composed primarily by calcium phosphate, in the form of mineral crystals. The mineral component confers bone with strength and stiffness while the organic phase is responsible for bone toughness and ductility and acts as a scaffold for the mineralisation process. The efficacy of bone as a structural material depends on the balance between these different bone components and their biomechanical properties. The main determinants of mechanical properties of bone are the amount of mineral, the collagen content, the orientation of the collagen fibers and minerals and the accumulation of microcracks in the bone matrix. In a mice model of arthritis mechanical testing has shown that arthritic femurs have a significantly lower Young's modulus, yield stress and work until ultimate stress. This evidence suggests that one of the major explanations for the increased fracture risk in RA is related to the changes on bone components induced by inflammation that result in compromised biomechanical properties.

Mourão AF, Caetano-Lopes J, Costa P, Canhão H, Santos MJ, Pinto P, Brito I, Nicola P, Cavaleiro J, Teles J, Sousa A, Gomes JM, Branco J, da Costa JT, Pedro JG, de Queiroz MV, Fonseca JE. · Rheumatology Research Unit, Instituto de Medicina Molecular, Edifício Egas Moniz, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal. · J Rheumatol. · Pubmed #19208590 No free full text.

Abstract: OBJECTIVE: Considering the relevance of tumor necrosis factor-alpha (TNF-alpha) in the pathophysiology of juvenile idiopathic arthritis (JIA), it is likely that polymorphisms in its promoter area may be relevant in disease susceptibility and activity. We investigated if clinical measures of JIA activity and TNF-alpha serum concentrations were associated with TNF-alpha -308 genotypes. METHODS: Portuguese patients with JIA in 5 pediatric rheumatology centers were recruited consecutively, along with a control group of healthy subjects. Demographic and clinical data and blood samples were collected from each patient. DNA was extracted for analysis of TNF-alpha gene promoter polymorphisms at position -308 by restriction fragment-length polymorphism. RESULTS: One hundred fourteen patients and 117 controls were evaluated; 57% of patients presented the oligoarticular subtype, 25% the polyarticular subtype, 8% the systemic subtype, and 9% had enthesitis-related arthritis and 5% psoriatic arthritis. Twenty-four percent of the patients presented the -308 GA/AA genotypes and 76% the -308 GG genotype, similar to findings in controls. Patients with the -308 GA/AA genotype had higher degree of functional impairment, erythrocyte sedimentation rate, 100-mm visual analog scale score for disease activity, and TNF-alpha levels compared to those with the -308 GG genotype. CONCLUSION: TNF-alpha -308 GA/AA genotypes were found to be related to higher inflammatory activity and worse measures of disease activity in Portuguese patients with JIA. They were not associated with susceptibility to JIA.

Canhao H, Fonseca JE, Caetano-Lopes J, Saldanha C, Queiroz MV. · Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Edifício Egas Moniz. Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal. · Clin Rheumatol. · Pubmed #17684700 No free full text.

Abstract: The aim of this study was to identify and evaluate laboratory parameters associated with normal bone mineral density (BMD) and to test if -308 tumour necrosis factor (TNF) alpha gene promoter polymorphisms could influence BMD. We performed a comparative cross-sectional study of four main groups: young healthy individuals (20-30 years); subjects aged 50 years or over with normal BMD; osteoporotic subjects aged 50 years or over; osteoporotic women with active rheumatoid arthritis. Variables assessed included anthropometric features, diet intake, lifestyle, calcium-phosphorus balance, markers of bone turnover, sexual hormones, hormones related with body mass and growth, cytokines involved in inflammation and bone turnover, and -308 TNF alpha gene promoter polymorphisms. One hundred fifty-nine subjects were evaluated. Across the four groups, zinc serum levels were higher in men as compared to women. In addition, zinc serum levels were also higher in individuals with normal BMD as compared to osteoporotic subjects. Serum calcium levels were higher in normal BMD group. On the other hand, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were significantly higher in normal bone mass postmenopausal women and men as compared to age-matched osteoporotic groups. Finally, leptin was significantly lower in men, after correcting these results for body mass index values. The remaining variables assessed had a similar distribution among the different studied groups. In our population, low serum levels of leptin and high serum levels of zinc, calcium, FSH, and LH were associated with a higher BMD.

Fonseca JE, Cavaleiro J, Teles J, Sousa E, Andreozzi VL, Antunes M, Amaral-Turkman MA, Canhão H, Mourão AF, Lopes J, Caetano-Lopes J, Weinmann P, Sobral M, Nero P, Saavedra MJ, Malcata A, Cruz M, Melo R, Braña A, Miranda L, Patto JV, Barcelos A, da Silva JC, Santos LM, Figueiredo G, Rodrigues M, Jesus H, Quintal A, Carvalho T, da Silva JA, Branco J, Queiroz MV. · Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av, Professor Egas Moniz, 1649-028, Lisboa, Portugal. · Arthritis Res Ther. · Pubmed #17408492 links to  free full text

Abstract: The objective of this study was to assess whether clinical measures of rheumatoid arthritis activity and severity were influenced by tumor necrosis factor-alpha (TNF-alpha) promoter genotype/haplotype markers. Each patient's disease activity was assessed by the disease activity score using 28 joint counts (DAS28) and functional capacity by the Health Assessment Questionnaire (HAQ) score. Systemic manifestations, radiological damage evaluated by the Sharp/van der Heijde (SvdH) score, disease-modifying anti-rheumatic drug use, joint surgeries, and work disability were also assessed. The promoter region of the TNF-alpha gene, between nucleotides -1,318 and +49, was sequenced using an automated platform. Five hundred fifty-four patients were evaluated and genotyped for 10 single-nucleotide polymorphism (SNP) markers, but 5 of these markers were excluded due to failure to fall within Hardy-Weinberg equilibrium or to monomorphism. Patients with more than 10 years of disease duration (DD) presented significant associations between the -857 SNP and systemic manifestations, as well as joint surgeries. Associations were also found between the -308 SNP and work disability in patients with more than 2 years of DD and radiological damage in patients with less than 10 years of DD. A borderline effect was found between the -238 SNP and HAQ score and radiological damage in patients with 2 to 10 years of DD. An association was also found between haplotypes and the SvdH score for those with more than 10 years of DD. An association was found between some TNF-alpha promoter SNPs and systemic manifestations, radiological progression, HAQ score, work disability, and joint surgeries, particularly in some classes of DD and between haplotypes and radiological progression for those with more than 10 years of DD.