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Background: Increased reactive oxygen species and estrogen deficiency contribute to the pathophysiology of postmenopausal osteoporosis. Reactive oxygen species contribute to bone degradation and is necessary for RANKLinduced osteoclast differentiation. In postmenopausal bone loss, reactive oxygen species can also activate immune cells to further enhance bone resorption. Here, we investigated the role of reactive oxygen species in ovariectomyinduced osteoporosis in mice deficient in Ncf1, a subunit for the NADPH oxidase 2 and a well-known regulator of the immune system. Methods: B10.Q wild-type (WT) mice and mice with a spontaneous point mutation in the Ncf1-gene (Ncf1*/*) were ovariectomized (ovx) or sham-operated. After 4 weeks, osteoclasts were generated ex vivo, and bone mineral density was measured using peripheral quantitative computed tomography. Lymphocyte populations, macrophages, pre-osteoclasts and intracellular reactive oxygen species were analyzed by flow cytometry. Results: After ovx, Ncf1*/*-mice formed fewer osteoclasts ex vivo compared to WT mice. However, trabecular bone mineral density decreased similarly in both genotypes after ovx. Ncf1*/*-mice had a larger population of preosteoclasts, whereas lymphocytes were activated to the same extent in both genotypes. Conclusion: Ncf1*/*-mice develop fewer osteoclasts after ovx than WT mice. However, irrespective of genotype, bone mineral density decreases after ovx, indicating that a compensatory mechanism retains bone degradation after ovx. [ABSTRACT FROM AUTHOR]

Background: Cardiac conduction disturbances are common in spondyloarthropathies such as ankylosing spondylitis (AS). Whether their occurrence can be linked to signs and symptoms of rheumatic disease activity is an unsettled issue addressed in this study. Methods: In this cross-sectional study patients with AS according to modified New York criteria but without psoriasis, inflammatory bowel disease, dementia, pregnancy, other severe diseases such as malignancy and difficulties in answering questionnaires were invited; and 210 participated (120 men), mean age 49 years (SD 13; range: 16-77). Questionnaires, physical examination, ECG, and laboratory tests were performed at the same visit. Results: Cardiac conduction disturbances were common and diagnosed in 10-33%, depending on if conservative or less conservative predefined criteria were applied. They consisted mostly of 1st degree atrio-ventricular block and prolonged QRS duration, but one patient had a pacemaker and 7 more had complete bundle branch blocks. Conduction abnormalities were associated mainly with age, male gender and body weight, and not with laboratory measures of inflammation or with Bath Ankylosing Spondylitis Disease Activity Index. Neither were they associated with the presence of HLA B27, which was found in 87% of all patients; the subtype B270502 dominated in all patients. Conclusions: Cardiac conduction abnormalities are common in AS, but not associated with markers of disease activity or specific B27 subtypes. Even relatively mild conduction system abnormalities might, however, indirectly affect morbidity and mortality. [ABSTRACT FROM AUTHOR]

Background: Collagen-induced arthritis (CIA) is an often-used murine model for human rheumatoid arthritis (RA). Earlier studies have shown potent anti-arthritic effects with the female sex hormone estradiol and the selective estrogen receptor modulator (SERM) raloxifene in CIA in DBA/1-mice. B10.Q-ncf1*/*mice are B10.Q mice with a mutated Ncf1 gene. In B10.Q-ncf1*/*mice, CIA develops as a chronic relapsing disease, which more accurately mimics human RA. We investigated the role of endogenous and exogenous sex steroids and raloxifene in the course of this model of chronic arthritis. We also examined whether treatment would prevent the development of inflammation-triggered generalized osteoporosis. Methods: Female B10.Q-ncf1*/*mice were sham-operated or ovariectomized, and CIA was induced. 22 days later, when 30% of the mice had developed arthritis, treatment with raloxifene, estradiol or vehicle was started, and the clinical disease was evaluated continuously. Treatment was continued until day 56 after immunization. At termination of the experiment (day 73), bone mineral density (BMD) was analyzed, paws were collected for histological examination, and sera were analyzed for markers of cartilage turnover and pro-inflammatory cytokines. Results: Raloxifene and estradiol treatment, as well as endogenous estrogen, decreased the frequency of arthritis, prevented joint destruction and countered generalized osteoporosis. These effects were associated with lower serum levels of the pro-inflammatory cytokine IL-6. Conclusions: This is the first study to show that raloxifene and estradiol can ameliorate established erosive arthritis and inflammation-triggered osteoporosis in this chronic arthritis model. We propose that treatment with raloxifene could be a beneficial addition to the treatment of postmenopausal RA. [ABSTRACT FROM AUTHOR]

Background: Estrogens and androgens have extensive effects on the immune system, for example they suppress both T and B lymphopoiesis in thymus and bone marrow. Submandibular glands are sexually dimorphic in rodents, resulting in larger granular convoluted tubules in males compared to females. The aim of the present experiments was to investigate the estrogenic and androgenic effects of 4-estren-3 α ,17β-diol (estren) on thymus, bone marrow and submandibular glands, and compare the effects to those of 17β-estradiol (E2) and 5 α -dihydrotestosterone (DHT), respectively. Estrogen receptors (ERs) were blocked by treatment of mice with the ER-antagonist ICI 182,780; also, knock-out mice lacking one or both ERs were used. Results: As expected, the presence of functional ERs was mandatory for all the effects of E2. Similar to DHT-treatment, estren-treatment resulted in decreased thymus weight, as well as decreased frequency of bone marrow B cells. Treatment with estren or DHT also resulted in a shift in submandibular glands towards an androgen phenotype. All the effects of estren and DHT were independent of ERs. Conclusion: Our study is the first to show that estren has similar effects as the androgen DHT on lymphopoiesis in thymus and bone marrow, and on submandibular glands, and that these effects are independent of estrogen receptors. This supports the hypothesis of estren being able to signal through the androgen receptor. [ABSTRACT FROM AUTHOR]

Background: Collagen-induced arthritis (CIA) is an often-used murine model for human rheumatoid arthritis (RA). Earlier studies have shown potent anti-arthritic effects with the female sex hormone estradiol and the selective estrogen receptor modulator (SERM) raloxifene in CIA in DBA/1-mice. B10.Q-ncf1*/*mice are B10.Q mice with a mutated Ncf1 gene. In B10.Q-ncf1*/*mice, CIA develops as a chronic relapsing disease, which more accurately mimics human RA. We investigated the role of endogenous and exogenous sex steroids and raloxifene in the course of this model of chronic arthritis. We also examined whether treatment would prevent the development of inflammation-triggered generalized osteoporosis.Methods: Female B10.Q-ncf1*/*mice were sham-operated or ovariectomized, and CIA was induced. 22 days later, when 30% of the mice had developed arthritis, treatment with raloxifene, estradiol or vehicle was started, and the clinical disease was evaluated continuously. Treatment was continued until day 56 after immunization. At termination of the experiment (day 73), bone mineral density (BMD) was analyzed, paws were collected for histological examination, and sera were analyzed for markers of cartilage turnover and pro-inflammatory cytokines.Results: Raloxifene and estradiol treatment, as well as endogenous estrogen, decreased the frequency of arthritis, prevented joint destruction and countered generalized osteoporosis. These effects were associated with lower serum levels of the pro-inflammatory cytokine IL-6.Conclusions: This is the first study to show that raloxifene and estradiol can ameliorate established erosive arthritis and inflammation-triggered osteoporosis in this chronic arthritis model. We propose that treatment with raloxifene could be a beneficial addition to the treatment of postmenopausal RA. [ABSTRACT FROM AUTHOR]

Introduction: Staphylococcus aureus is a common cause of bacterial arthritis, which is associated with progressive bone loss in affected joints. We recently showed that S. aureus infection also induces a significant systemic bone loss in mice. This study was performed to assess the effect of estradiol treatment on the clinical course and outcome of S. aureus arthritis and on infection-induced bone loss in experimental S. aureus infection., Methods: Mice were ovariectomized, treated with estradiol or placebo, and S. aureus infection was established by intravenous inoculation of bacteria., Results: Estradiol treatment was found to decrease significantly the frequency and clinical severity of S. aureus arthritis, a finding that was accompanied with significantly higher serum levels of interleukin-10 in estradiol-treated mice. Estradiol was also highly protective against S. aureus-induced systemic trabecular, and cortical bone loss. Lack of endogenous estrogens and S. aureus infection had additive effects on trabecular bone loss. The S. aureus-infected, ovariectomized mice lost as much as 76% of their trabecular bone mass., Conclusions: Treatment with estradiol ameliorates S. aureus arthritis and is protective against infection-induced systemic bone loss in experimental S. aureus infection.

Background: The aims were to explore bone mineral density (BMD) by digital X-ray radiogrammetry (DXR) in postmenopausal women with long-lasting rheumatoid arthritis (RA) in relation to dual x-ray absorptiometry (DXA)-BMD, joint destruction by conventional radiographs and disease related variables in a cross-sectional study., Methods: Seventy-five postmenopausal women with RA were examined by DXA measuring DXA-BMD of the forearm, total hip and lumbar spine, by scoring joint destruction on plain radiographs by the method of Larsen and by DXR-BMD in metacarpals two to four. The DXR-BMD results of the RA women were compared with an age and sex-matched reference database. A function of DXR-BMD in relation to age and disease duration was created. Associations were investigated by bivariate and multiple linear regression analyses., Results: DXR-BMD was strongly decreased in RA patients compared to the reference database (p < 0.001). Calculations showed that DXR-BMD was not markedly influenced the first years after diagnosis of RA, but between approximately 5-10 years of disease there was a steep decline in DXR-BMD which subsequently levelled off. In multiple regression analyses disease duration, CRP and DXR-BMD were independent variables associated with Larsen score (R2= 0.64). Larsen score and BMD forearm were independent determinants of DXR-BMD (R2 = 0.79)., Conclusions: DXR-BMD was strongly reduced and associated with both Larsen score and DXA-BMD forearm in these postmenopausal women with RA implying that DXR-BMD is a technique that reflects both the erosive process and bone loss adjacent to affected joints.

Introduction: Postmenopausal patients with rheumatoid arthritis (RA) are often treated with corticosteroids. Loss of estrogen, the inflammatory disease and exposure to corticosteroids all contribute to the development of osteoporosis. Therefore, our aim was to investigate if addition of the selective estrogen receptor modulator raloxifene, or estradiol, could prevent loss of bone mineral density in ovariectomized and dexamethasone treated mice with collagen-induced arthritis (CIA)., Methods: Female DBA/1-mice were ovariectomized or sham-operated, and CIA was induced. Treatment with dexamethasone (Dex) (125 μg/d), estradiol (E2) (1 μg/d) or raloxifene (Ral) (120 μg/day) alone, or the combination of Dex + E2 or Dex + Ral, was started after disease onset, and continued until termination of the experiments. Arthritic paws were collected for histology and one of the femoral bones was used for measurement of bone mineral density., Results: Dex-treatment alone protected against arthritis and joint destruction, but had no effect on osteoporosis in CIA. However, additional treatment with either Ral or E2 resulted in completely preserved bone mineral density., Conclusions: Addition of raloxifene or estradiol to dexamethasone-treatment in experimental postmenopausal polyarthritis prevents generalized bone loss.

Introduction: Our objective was to determine the frequency of and factors associated with prevalent vertebral compression fractures in female systemic lupus erythematosus (SLE) patients attending rheumatologists in western Sweden., Methods: In this cross sectional study 150 women were included. They were examined with x-ray of thoracic and lumbar spine (Th4 to L4). A reduction of at least 20% of any vertebral height, assessed by Genant's semiquantitative method, was defined as a fracture. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DXA)., Results: Median patient age was 47 years (20 to 82) and disease duration 11 years (1 to 41). Only 6 (4%) women had a history of clinical compressions whereas 43 (29%) had at least one radiological fracture each. The patients with at least one fracture at any site were characterized by older age (P < 0.001), being postmenopausal (P < 0.01), higher Systemic Lupus International Collaborative Clinics Damage Index (P < 0.05), lower BMD total hip and femoral neck (P < 0.05), more peripheral fractures (P < 0.01), medication with bisphosphonates (P <0.05) and calcium and vitamin D3 (P < 0.05). There were no significant differences regarding current or cumulative glucocorticosteroid dose between the groups. In logistic regression analyses high age remained as a risk factor of at least one vertebral fracture at any site whereas low BMD in total hip was associated with vertebral fracture in the lumbar spine., Conclusions: Radiological compression fractures are common but seldom diagnosed in SLE patients. High age and low BMD in total hip, but not in spine, was associated with vertebral fractures.

Introduction: Resistin is a cystein-rich secretory adipokine. It is proposed to have proinflammatory properties in humans. The aim of this study was to determine associations between serum levels of resistin and markers of inflammation and bone mineral density (BMD) in female patients with systemic lupus erythematosus (SLE)., Methods: One hundred sixty-three female patients with SLE (20 to 82 years old) were examined in a cross-sectional study. Venous blood samples were analyzed for resistin, erythrocyte sedimentation rate (ESR), C-reactive protein, creatinine, fasting lipids, complements, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, sIL-6R (soluble IL-6 receptor), ICTP (C-terminal telopeptide of type I collagen), and PINP (N-terminal propeptide of type I procollagen). Simple and multiple regression analyses as well as logistic regression analyses were performed. Resistin in serum was compared with 42 healthy female controls with respect to age., Results: Serum resistin levels in controls were similar to those of patients with SLE. Markers of inflammation and current dose of glucocorticosteroids correlated positively to resistin in serum. Markers of renal function, number of prevalent vertebral fractures, and BMD were also significantly associated with resistin. In a multiple regression model, ESR, creatinine, C3, current glucocorticosteroid dose, high-density lipoprotein, and BMD radius remained significantly associated with resistin. In logistic regression analyses with resistin as the independent variable, a significant association was found with ESR (normal or elevated) but not with S-creatinine or z score for hip and radius total., Conclusion: Although resistin measurements did not differ between patients and controls, resistin was clearly associated with general inflammation, renal disease, treatment with glucocorticosteroids, and bone loss. We hypothesize that resistin has proinflammatory and disease-promoting properties in SLE. Further studies are needed to elucidate the mechanism behind these associations.

Generalized osteoporosis in postmenopausal rheumatoid arthritis (RA) is caused both by estrogen deficiency and by the inflammatory disease. The relative importance of each of these factors is unknown. The aim of this study was to establish a murine model of osteoporosis in postmenopausal RA, and to evaluate the relative importance and mechanisms of menopause and arthritis-related osteoporosis. To mimic postmenopausal RA, DBA/1 mice were ovariectomized, followed by the induction of type II collagen-induced arthritis. After the mice had been killed, paws were collected for histology, one femur for bone mineral density (BMD) and sera for analyses of markers of bone resorption (RatLaps; type I collagen cross-links, bone formation (osteocalcin) and cartilage destruction (cartilage oligomeric matrix protein), and for the evaluation of antigen-specific and innate immune responsiveness. Ovariectomized mice displayed more severe arthritis than sham-operated controls. At termination of the experiment, arthritic control mice and non-arthritic ovariectomized mice displayed trabecular bone losses of 26% and 22%, respectively. Ovariectomized mice with arthritis had as much as 58% decrease in trabecular BMD. Interestingly, cortical BMD was decreased by arthritis but was not affected by hormonal status. In addition, markers of bone resorption and cartilage destruction were increased in arthritic mice, whereas markers of bone formation were increased in ovariectomized mice. This study demonstrates that the loss of endogenous estrogen and inflammation contribute additively and equally to osteoporosis in experimental postmenopausal polyarthritis. Markers of bone remodeling and bone marrow lymphocyte phenotypes indicate different mechanisms for the development of osteoporosis caused by ovariectomy and arthritis in this model.