Rheumatoid Arthritis In Postmenopausal Women Research Articles

Enhanced susceptibility to low‐dose collagen‐induced arthritis in CR1/2‐deficient female mice—possible role of estrogen on CR1 expression

The influence of complement receptor 1 and 2 (CR1/2) was investigated on the susceptibility to low-dose collagen-induced arthritis (CIA) in wild-type (WT) and CR1/2-deficient DBA/1 mice. Significantly enhanced CIA was observed in female CR1/2-deficient mice compared with WT female mice, while male mutant and WT mice showed similar arthritis development. The enhanced CIA was accompanied with higher complement levels and a prolonged IgM anti-collagen type II response. When investigating whether estrogen contributed to the different arthritis susceptibility, we found that ovariectomy rendered WT females more sensitive to low-dose CIA and to the same extent as CR1/2-deficient females, while CR1/2-deficient mice were unaffected by ovariectomy. Notably, the ovariectomized WT mice displayed reduced CR1(+) B220(+) B-cell numbers and CR1 expression compared with sham-operated WT mice, suggesting a stimulatory effect of estrogen on CR1. In accordance, a significant correlation was observed between reduced CR1 expression in B cells and increased age in healthy female blood donors but not in male donors. Our findings demonstrate an important role of CR1/2 in suppressing CIA in female mice under low-antigen conditions. The data suggest that estrogen promote CR1 expression in B cells. These findings provide insight to the increased frequency of rheumatoid arthritis in postmenopausal women.

Forearm bone mineral density in postmenopausal women with rheumatoid arthritis.

Osteoporosis in cases of rheumatoid arthritis (RA) is multifactorial, and the pathogenesis of bone loss induced by RA in postmenopausal women is not fully understood. The purpose of the present study was to determine the factors that affect forearm bone mineral density (BMD) in postmenopausal women with RA. In total, 839 postmenopausal women aged 46-90 years, were enrolled in the study; 470 patients with RA and 369 healthy controls (CON). Forearm (distal radius) BMD, measured by DXA using a DTX-200 (Osteometer, MediTech, CA, USA), was significantly lower in the RA group than in the CON group (P < 0.0001), even when adjusted for age, height, body weight, body mass index, and years since menopause (YSM) (P < 0.01). On multiple regression analysis, in the CON group, age and YSM were significantly correlated with BMD (P < 0.01 and P < 0.05, respectively). On the other hand, in the RA group, in addition to YSM, anatomic grade in the wrist, modified health assessment questionnaire (HAQ) score for the upper extremities, and erythrocyte sedimentation rate were each significantly correlated with BMD (P < 0.0001, P < 0.001, P < 0.0001, and P < 0.001, respectively), whereas functional class, duration of disease, dose of prednisolone used, modified HAQ score for the lower extremities, and the levels of c-reactive protein and rheumatoid factor were not. The present study with a large number of subjects shows that in addition to YSM, disuse (anatomic grade) of the wrist, arm function, and disease activity appear to be significant determinants of forearm BMD in postmenopausal women with RA.