Rheumatoid Arthritis: Shalley G

Dalbeth N, Smith T, Gray S, Doyle A, Antill P, Lobo M, Robinson E, King A, Cornish J, Shalley G, Gao A, McQueen FM. · Bone Research Group, Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland, New Zealand. · Ann Rheum Dis. · Pubmed #18765428 No free full text.

Abstract: OBJECTIVES: Magnetic resonance imaging (MRI) bone oedema is an important predictor of bone erosion in rheumatoid arthritis (RA). This study aimed to determine the cellular components of MRI bone oedema, and clarify the relationship between bone erosion and MRI bone oedema. METHODS: Twenty-eight bones from 11 patients with RA undergoing orthopaedic surgery were analysed by quantitative and semi-quantitative immunohistochemistry. Pre-operative contrast-enhanced MRI scans were analysed for bone oedema. RESULTS: The density of osteoclasts was higher in those samples with MRI bone oedema than those without MRI bone oedema (p = 0.01). Other cells identified within bone marrow included macrophages and plasma cells, and these were more numerous in samples with MRI bone oedema (p = 0.02 and 0.05 respectively). B cells were present in lower numbers, but B cell aggregates were identified in some samples with MRI bone oedema. There was a trend to increased RANKL expression in samples with MRI bone oedema (p = 0.09). Expression of RANKL correlated with the number of osteoclasts (r = 0.592, p = 0.004). CONCLUSIONS: The increased number of osteoclasts and RANKL expression in samples with MRI bone oedema supports the hypothesis that bone erosion in RA occurs through activation of local bone resorption mechanisms within subchondral bone as well as through synovial invasion into bone.

McQueen FM, Gao A, Ostergaard M, King A, Shalley G, Robinson E, Doyle A, Clark B, Dalbeth N. · Department of Molecular Medicine and Pathology, Faculty of Medicine and Health Sciences, University of Auckland, Park Rd, Private Bag 92019 Auckland, New Zealand. · Ann Rheum Dis. · Pubmed #17491098 No free full text.

Abstract: OBJECTIVES: MRI bone oedema has been observed in early and advanced RA and may represent a cellular infiltrate (osteitis) in subchondral bone. We studied MRI scans from RA patients undergoing surgery, seeking to identify regions of bone oedema and examine its histopathological equivalent in resected bone. METHODS: Preoperative contrast-enhanced MRI scans were obtained in 11 RA patients scheduled for orthopaedic surgery to the hands/wrists or feet. In 9, MRI scans were scored by 2 readers for bone oedema (RAMRIS system). Its distribution with respect to surgical site was investigated. In 4 patients, 7 bone samples were examined for a cellular infiltrate, and this was compared with MRI bone oedema, scored for spatial extent and intensity. RESULTS: Inter-reader intraclass correlation coefficients for bone oedema were 0.51 (all sites) and 0.98 (bone samples for histology). Bone oedema was observed at 60% of surgical sites vs 38% of non-surgical sites. High-grade bone oedema (score >/=50% maximum) was strongly associated with the surgical field (OR 9.3 (3.5 to 24.2), p<0.0001). Bone oedema scores correlated with pain (r = 0.67, p = 0.048) and CRP (r = 0.86, p = 0.01). In 4 of the 7 bone samples, there was concordance between bone oedema and subchondral osteitis. In 3, there was no MRI bone oedema, and osteitis was "slight". CONCLUSION: High-grade MRI bone oedema was common within the field of intended surgery and associated with pain. There was concordance between the presence and severity of MRI bone oedema and osteitis on histology, with an MRI threshold effect due to differences in image resolution.