Inflammation-induced bone loss: can it be prevented?

Defects in osteoblast function but no changes in long-term repopulating potential of hematopoietic stem cells in a mouse chronic inflammatory arthritis model

Recent studies support the notion that there is an intricate relationship between hematopoiesis and bone homeostasis in normal steady states. Using mice undergoing chronic inflammatory arthritis, we investigated the relationship between hematopoiesis and bone homeostasis in pathologic conditions. We demonstrate that mice undergoing chronic inflammatory arthritis displayed osteoporosis resulting from a severe defect in osteoblast function. Despite the defective osteoblast function, however, the hematopoietic stem cells from these mice exhibited normal properties in either long-term repopulation or cell cycling. Therefore, the bone-forming capacity of osteoblasts is distinct from their ability to maintain hematopoietic stem cells in chronic inflammatory conditions.

Association between osteoporosis and rheumatoid arthritis in women: a cross-sectional study

CONTEXT AND OBJECTIVES

Osteoporosis has frequently been observed in patients with rheumatoid arthritis. The present study was undertaken in order to evaluate factors associated with osteoporosis among women with rheumatoid arthritis.

DESIGN AND SETTING

Cross-sectional study, carried out in a public hospital in São Paulo.

METHODS

The participants were 83 women with rheumatoid arthritis (53.7 +/- 10.0 years old). Bone mineral density (BMD) and body composition were measured by dual energy X-ray absorptiometry. The patients were divided into three groups according to BMD: group 1, normal BMD (n = 24); group 2, osteopenia (n = 38); and group 3, osteoporosis (n = 21). Tests were performed to compare differences in means and correlations, with adjustments for age, duration of disease and cumulative corticosteroid. The relationships between clinical factors, physical activity score, dietary intake, body composition and biochemical parameters were analyzed using linear regression models.

RESULTS

Mean calcium, vitamin D and omega-6 intakes were lower than the recommendations. Associations were found between BMD and age, disease duration, parathyroid hormone concentration and fat intake. The linear regression model showed that being older, with more years of disease and lower weight were negatively correlated with BMD [Total femur = 0.552 + 0.06 (weight) + 0.019 (total physical activity) - 0.05 (age) - 0.003 (disease duration); R(2) = 48.1; P < 0.001].

CONCLUSION

The present study indicates that nutritional factors and body composition are associated with bone mass in women with rheumatoid arthritis.

Adalimumab therapy reduces hand bone loss in early rheumatoid arthritis: explorative analyses from the PREMIER study

OBJECTIVE

The effect of adalimumab on hand osteoporosis was examined and related to radiographic joint damage in the three treatment arms of the PREMIER study: adalimumab plus methotrexate, adalimumab and methotrexate monotherapy. Predictors of hand bone loss were also searched for.

METHODS

768 patients (537 fulfilled 2 years) with rheumatoid arthritis (RA) for less than 3 years, never treated with methotrexate, were included. Hand bone loss was assessed by digital x ray radiogrammetry (DXR) on the same hand radiographs scored with modified Sharp score at baseline, 26, 52 and 104 weeks. For DXR, metacarpal cortical index (MCI) was the primary bone measure.

RESULTS

At all time points the rate of percentage DXR-MCI loss was lowest in the combination group (-1.15; -2.16; -3.03) and greatest in the methotrexate monotherapy group (-1.42; -2.87; -4.62), with figures in between for the adalimumab monotherapy group (-1.33; -2.45; -4.03). Significant differences between the combination group and the methotrexate group were seen at 52 (p = 0.009) and 104 weeks (p<0.001). The order of hand bone loss across the three treatment arms was similar to the order of radiographic progression. Older age, elevated C-reactive protein and non-use of adalimumab were predictors of hand bone loss.

CONCLUSION

This study supports a similar pathogenic mechanism for hand bone loss and erosions in RA. The combination of adalimumab and methotrexate seems to arrest hand bone loss less effectively than radiographic joint damage. Quantitative measures of osteoporosis may thus be a more sensitive tool for assessment of inflammatory bone involvement in RA.

Toll gates to periodontal host modulation and vaccine therapy

Toll-like receptors (TLRs) are central mediators of innate antimicrobial and inflammatory responses and play instructive roles in the development of the adaptive immune response. Thus when stimulated by certain agonists, TLRs serve as adjuvant receptors that link innate and adaptive immunity. However, when excessively activated or inadequately controlled during an infection, TLRs may contribute to immunopathology associated with inflammatory diseases, such as periodontitis. Moreover, certain microbial pathogens appear to exploit aspects of TLR signalling in ways that enhance their adaptive fitness. The diverse and important roles played by TLRs suggest that therapeutic manipulation of TLR signalling may have implications in the control of infection, attenuation of inflammation, and the development of vaccine adjuvants for the treatment of periodontitis. Successful application of TLR-based therapeutic modalities in periodontitis would require highly selective and precisely targeted intervention. This would in turn necessitate precise characterization of TLR signalling pathways in response to periodontal pathogens, as well as development of effective and specific agonists or antagonists of TLR function and signalling. This review summarizes the current status of TLR biology as it relates to periodontitis, and evaluates the potential of TLR-based approaches for host-modulation therapy in this oral disease.

Effect of tumor necrosis factor alpha inhibition on bone density and turnover markers in patients with rheumatoid arthritis and spondyloarthropathy

OBJECTIVES

Anti-tumor necrosis factor-alpha (TNFalpha) therapy has proven efficacious in improving both disease activity and focal bone erosions in patients with rheumatoid arthritis (RA) and spondyloarthopathies. We review the current literature reporting on the effect of anti-TNFalpha on bone density as measured by dual energy radiograph absorptiometry at the lumbar spine and hip, as well as markers of bone turnover and resorption, in patients using anti-TNFalpha for rheumatic disease indications.

METHODS

A PubMed search, as well as manual search of related articles and references of articles retrieved, was performed to identify all studies pertaining to the effect of anti-TNFalpha therapy on bone mineral density (BMD) and bone turnover markers.

RESULTS

In RA, 4 studies (238 patients) showed a stabilization or increase of BMD at the spine (up to 2.8%) or hip (up to 13.1%), with only 1 negative study in 48 patients (decline of 3.2% at the spine and 2.7% at the hip). In spondyloarthopathies, 3 studies (75 patients) all demonstrated an increase in BMD at the lumbar spine (3.2-3.6%) and at the hip (1.8-2.2%). Changes in markers of bone formation and bone resorption were heterogeneous but in general represented a modest increase in formation and decline in resorption.

CONCLUSIONS

In general, anti-TNFalpha therapy has a beneficial effect on bone density and bone turnover markers. Retrieved studies were heterogeneous with regards to patients studied, underlying risks for osteoporosis, and supplemental therapy, which may limit the findings of the true effect of anti-TNFalpha therapy on bone.

An update on glucocorticoid-induced osteoporosis

PURPOSE OF REVIEW

Glucocorticoids are widely used, often long term, and a major side effect is osteoporosis and increased risk of fracture. This review considers how common is the problem, the patients who are most at risk, our current understanding of mechanisms, and how to prevent and effectively treat glucocorticoid-induced osteoporosis. The actions currently being undertaken in clinical practice are reviewed.

RECENT FINDINGS

Glucocorticoid-induced osteoporosis is an increasing problem that occurs not only in those on high-dose therapy. Advances in our knowledge of the cellular and cytokine mechanisms of bone turnover and glucocorticoid mechanisms of action are leading to a better understanding of how glucocorticoids affect bone cells and novel ways of prevention. Although there are effective treatments to prevent and control glucocorticoid-induced osteoporosis as well as guidelines for their use, they are still not being applied in routine clinical practice.

SUMMARY

Glucocorticoid-induced osteoporosis is a significant problem. Although our understanding of effective prevention and treatment strategies is improving, there needs to be better implementation of these strategies.