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Osteoclastogenesis in iliac bone marrow of patients with rheumatoid arthritis
Y Toritsuka1, N Nakamura, S B Lee
1Department of Orthopaedic Surgery, Osaka University Medical School, Japan.
Insights
Rheumatoid arthritis (RA) patients, particularly those with severe RA, show increased bone resorption and osteoclastogenesis. These findings suggest a link between RA and generalized osteoporosis.
Area of Science:
- Rheumatology
- Osteoporosis Research
- Cell Biology
Background:
- Osteoporosis is a significant health concern, particularly in patients with rheumatoid arthritis (RA).
- Understanding the cellular mechanisms driving bone loss in RA is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate osteoclastogenesis in bone marrow cells from patients with rheumatoid arthritis (RA).
- To identify specific factors contributing to generalized osteoporosis in RA patients.
Main Methods:
- Bone marrow blood was collected from 59 women (36 with RA, 23 without).
- Pyridinoline crosslinked telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase positive multinucleated cells (TRAP positive MNC) were measured to assess bone resorption and osteoclastogenesis.
Main Results:
- Elevated ICTP concentrations and increased TRAP positive MNC were observed in the bone marrow supernatant of some severe RA patients.
- These markers of bone resorption and osteoclastogenesis were not enhanced in control groups.
Conclusions:
- Increased bone resorption and osteoclastogenesis are specifically linked to the iliac bone marrow of RA patients, especially those with severe disease.
- These cellular changes are considered to be associated with generalized osteoporosis in rheumatoid arthritis.
Objective:
To investigate osteoclastogenesis in bone marrow cells from patients with various pathogenic backgrounds known to induce osteoporosis, to identify specific factors that may cause generalized osteoporosis in patients with rheumatoid arthritis (RA).
Methods:
Bone marrow blood was obtained from 59 women, 36 with RA and 23 without RA. Patients with RA were classified as severe (26) and mild RA (10: 5 patients with and 5 without corticosteroid therapy). The non-RA subjects were divided into 3 groups, premenopausal (7), menopausal (8), and elderly (8). As a marker of bone resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP) concentration in the bone marrow supernatant was measured by radioimmunoassay. The bone marrow cells were cultured 14 days in the presence or absence of autologous bone marrow supernatant; then the number of tartrate resistant acid phosphatase positive multinucleated cells (TRAP positive MNC) was counted as an indicator of osteoclastogenesis.
Results:
ICTP concentration of the bone marrow supernatant and the number of TRAP positive MNC showed remarkable enhancement in some patients with severe RA, but these features were not observed in the 3 control groups.
Conclusion:
Increased bone resorption and enhanced osteoclastogenesis were specifically observed in the iliac bone marrow of patients with RA, especially those with severe RA. These phenomena can be considered to accompany generalized osteoporosis in RA.