Inflammatory related changes in bone mineral content in adults with cystic fibrosis.

BACKGROUND: Proinflammatory cytokines stimulate osteoclast activity and this could lead to increased bone resorption in patients with cystic fibrosis. The aim of this study was to determine whether markers of systemic inflammation are related to changes in bone mineral content (BMC) in adults with cystic fibrosis. METHODS: Total body BMC was assessed by dual energy x ray absorptiometry in 100 patients (54 male) of mean (SD) age 25.6 (7.1) years and forced expiratory volume in 1 second (FEV(1)) 61.8 (24.1)% predicted on recruitment to the study and 1 year later. Blood was also taken at these time points to measure markers of systemic inflammation. RESULTS: After 1 year BMC had reduced by 16.1 (62.1) g, p = 0.01; (0.6 (2.8)%). The change in BMC was related to mean levels of interleukin (IL)-6 (r(s) = -0.39, p<0.001) and C reactive protein (r(s) = -0.34, p = 0.002), intravenous antibiotic use (r(s) = -0.27, p = 0.006) and oral corticosteroid use (r(s) = -0.20, p = 0.045). Urinary markers of osteoclast activity were also related to IL-6 (r(s) = 0.27, p = 0.02). Multiple linear regression revealed that IL-6 (coefficient -2.2 (95% CI -3.4 to -1.0) per pg/ml, p = 0.001), colonisation with Burkholderia cepacia (coefficient -46.8 (95% CI -75.5 to -18.1), p = 0.002), and annual change in BMI (coefficient 15.4 (95% CI 3.6 to 27.2) per kg/m(2), p = 0.011) were independently significant predictors of annual change in BMC. CONCLUSIONS: These data suggest a pathophysiological mechanism by which chronic pulmonary infection results in bone loss in patients with cystic fibrosis.

A prospective study of change in bone mineral density over one year in adults with cystic fibrosis.

BACKGROUND: Low bone mineral density (BMD) is prevalent in adults with cystic fibrosis. To identify appropriate therapeutic strategies and the optimal time for intervention, it is necessary to document the natural history of cystic fibrosis related low BMD. METHODS: 114 adults with cystic fibrosis underwent bone densitometry a median (25-75% interquartile range) of 12 (12-13) months after initial assessment of bone density. BMD was measured in the lumbar spine, femoral neck, total hip, and distal forearm on recruitment to the trial and at follow up. RESULTS: In patients or=25 years of age (n=59, mean (SD) age 30.3 (5.4) years) in whom no annual change in BMD would normally be expected, BMD decreased by 1.9% (95% CI -2.9 to -0.8) per year in the femoral neck (p<0.001), by 1.5% (95% CI -2.4 to -0.6) per year in the total hip (p=0.001), and by 0.8% (95% CI -1.5 to -0.1) per year in the distal forearm (p=0.026). There was no significant annual change in lumbar spine BMD in either patient cohort. CONCLUSIONS: Reduced rates of bone accretion and accelerated rates of bone loss explain the high prevalence of low BMD in adults with cystic fibrosis.

Bisphosphonates in the treatment of Charcot neuroarthropathy: a double-blind randomised controlled trial.

AIMS/HYPOTHESIS: The management of charcot neuroarthropathy, a severe disabling condition in diabetic patients with peripheral neuropathy, is currently inadequate with no specific pharmacological treatment available. We undertook a double-blind randomised controlled trial to study the effect of pamidronate, a bisphosphonate, in the management of acute diabetic Charcot neuroarthropathy. METHODS: Altogether 39 diabetic patients with active Charcot neuroarthropathy from four centres in England were randomised in a double-blind placebo-controlled trial. Patients received a single infusion of 90 mg of pamidronate or placebo (saline). Foot temperatures, symptoms and markers of bone turnover (bone specific alkaline phosphatase and deoxypyridinoline crosslinks) were measured over the 12 months, in 10 visits. All patients also had standard treatment of the Charcot foot. RESULTS: Mean age of the study group (59 % Type II (non-insulin-dependent) diabetes mellitus) was 56.3 +/- 10.2 years. The mean temperature difference between active and control groups was 3.6 +/- 1.7 degrees C and 3.3 +/- 1.4 degrees C, respectively. There was a fall in temperature of the affected foot in both groups after 2 weeks with a further reduction in temperature in the active group at 4 weeks (active and placebo vs baseline; p = 0.001; p = 0.01, respectively), but no difference was seen between groups. An improvement in symptoms was seen in the active group compared with the placebo group (p < 0.001). Reduction in bone turnover (means +/- SEM) was greater in the active than in the control group. Urinary deoxypyridinoline in the pamidronate treated group fell to 4.4 +/- 0.4 nmol/mmol creatinine at 4 weeks compared with 7.1 +/- 1.0 in the placebo group (p = 0.01) and bone-specific alkaline phosphatase fell to 14.1 +/- 1.2 u/l compared with 18.6 +/- 1.6 u/l after 4 weeks, respectively (p = 0.03). CONCLUSION/INTERPRETATION: The bisphosphonate, pamidronate, given as a single dose leads to a reduction in bone turnover, symptoms and disease activity in diabetic patients with active Charcot neuroarthropathy.

Effect of intravenous pamidronate on bone mineral density in adults with cystic fibrosis.

BACKGROUND: Low bone mineral density (BMD) is prevalent in adults with cystic fibrosis. The aim of this study was to assess the effect of intravenous pamidronate on BMD in these subjects. METHODS: Patients were invited to participate if they had a BMD Z score of -2 or less in the lumbar spine, proximal femur, or distal forearm. Patients were randomised to receive either 30 mg intravenous pamidronate every 3 months + 1 g calcium daily (pamidronate group) or 1 g calcium daily (control group). All pancreatic insufficient patients were prescribed oral vitamin D supplements. RESULTS: After 6 months of treatment the pamidronate group (n=13) showed a significant increase in absolute BMD compared with the control group (n=15) in the lumbar spine (mean difference 5.8% (CI 2.7% to 8.9%)) and total hip (mean difference 3.0% (CI 0.3% to 5.6%)). However, the pamidronate group showed a reduction in BMD compared with the control group in the distal forearm (mean difference -1.7% (CI -3.7% to 0.3%)). The use of pamidronate was associated with a high incidence of bone pain in non-corticosteroid treated individuals. CONCLUSION: Intravenous pamidronate increases axial BMD in adults with cystic fibrosis, but the high incidence of bone pain associated with this treatment might limit its use.

Localization of estrogen receptor beta protein expression in adult human bone.

Evidence suggests that the newly described estrogen receptor beta (ER-beta) may be important for estrogen (17beta-estradiol) action on the skeleton, but its cellular localization in adult human bone requires clarification. We addressed this by using indirect immunoperoxidase with a novel affinity purified polyclonal antibody to human ER-beta, raised to hinge domain (D) sequences from the human receptor. Bone was demineralized in 20% EDTA and all biopsy specimens were formalin-fixed and wax-embedded. Vigorous retrieval was essential for ER-beta detection. In sections (5 microm) of benign prostate hyperplasia, used as positive control, clear nuclear immunoreactivity was seen in glandular epithelial cells, with a 1:500 dilution of ER-beta40. For bone sections, optimal antibody dilutions were 1:100-1:250. We found that in normal bone (from graft operations), in fracture callus from both men and women (>25 years old), pagetic bone, osteophytes, and secondary hyperparathyroid bone, all from older patients, ER-beta was expressed clearly in osteoclast nuclei, with little cytoplasmic immunoreactivity. Nuclear immunoreactivity was still prominent in osteoclasts, with antibody diluted 1:500, although it faded in other cells. Osteoblasts, in areas of active bone formation or bone remodeling, also expressed ER-beta, as did some osteocytes. However, hypertrophic chondrocytes were negative, unlike mesenchymal cells, adjacent to the osteogenesis. Megakaryocytes and some capillary blood vessels cells were receptor positive. All ER-beta expression was blocked totally by preincubation of antibody with antigen. We conclude that ER-beta is expressed in cells of osteoblast lineage and in osteoclasts. The latter appear relatively abundant in this receptor and this might provide a means for direct action of estrogen on osteoclasts.

A negative search for a paramyxoviral etiology of Paget's disease of bone: molecular, immunological, and ultrastructural studies in UK patients.

Paget's disease of bone is a common bone disease characterized by increased and disorganized bone remodeling at focal sites throughout the skeleton. The etiology of the disease is unresolved. A persistent viral infection has long been suggested to cause the disease. Antigen and/or nucleic acid sequences of paramyxoviruses (in particular measles virus [MV], canine distemper virus [CDV], and respiratory syncytial virus [RSV]) have been reported in pagetic bone by a number of groups; however, others have been unable to confirm this and so far no virus has been isolated from patients. Here, we reexamined the question of viral involvement in Paget's disease in a study involving 53 patients with established disease recruited from seven centers throughout the United Kingdom. Thirty-seven patients showed clear signs of active disease by bone scan and/or histological assessment of the bone biopsy specimens and 12 of these had not received any therapy before samples were taken. Presence of paramyxovirus nucleic acid sequences was sought in bone biopsy specimens, bone marrow, or peripheral blood mononuclear cells using reverse-transcription polymerase chain reaction (RT-PCR) with a total of 18 primer sets (7 of which were nested), including 10 primer sets (including 3 nested sets) specifically for MV or CDV. For each patient at least one sample was tested with all primer sets by RT-PCR and no evidence for the presence of paramyxovirus RNA was found in any patient. In 6 patients, bone biopsy specimens with clear histological evidence of active disease tested negative for presence of measles and CDV using immunocytochemistry (ICC) and in situ hybridization (ISH). Intranuclear inclusion bodies, similar to those described by others previously, were seen in pagetic osteoclasts. The pagetic inclusions were straight, smooth tubular structures packed tightly in parallel bundles and differed from nuclear inclusions, known to represent MV nucleocapsids, in a patient with subacute sclerosing panencephalitis (SSPE) in which undulating, diffuse structures were found, arranged loosely in a nonparallel fashion. In the absence of amplification of viral sequences from tissues that contain frequent nuclear inclusions and given that identical inclusions are found in other bone diseases with a proven genetic, rather than environmental, etiology, it is doubtful whether the inclusions in pagetic osteoclasts indeed represent viral nucleocapsids. Our findings in this large group of patients recruited from throughout the United Kingdom do not support a role for paramyxovirus in the etiology of Paget's disease.

Progestins abrogate estrogen-induced changes in the insulin-like growth factor axis.

OBJECTIVE: We sought to investigate the effect of oral progestins on estrogen-mediated changes in the insulin-like growth factor axis in the peripheral circulation. STUDY DESIGN: Oral conjugated equine estrogen alone or in combination with medroxyprogesterone acetate, desogestrel, or norethindrone was given in a randomized triple-crossover fashion to 10 healthy postmenopausal women, and the effects on the insulin-like growth factor axis were determined. RESULTS: Baseline circulating insulin-like growth factor I levels were significantly reduced by conjugated equine estrogen (359 +/- 54 vs 225 +/- 44 ng/mL; P =.0001). This effect was reversed by progestins (medroxyprogesterone acetate, 254 +/- 44 ng/mL; desogestrel, 266 +/- 50 ng/mL; norethindrone, 286 +/- 48 ng/mL; F = 12.2; P =.0015). Free insulin-like growth factor I was reduced by conjugated equine estrogen (1.00 +/- 0.15 ng/mL vs 2.10 +/- 0.39 ng/mL; P =.004), but addition of progestogens had no further effect. Insulin-like growth factor II and insulin levels were unaffected by conjugated equine estrogen or progestins. Plasma insulin-like growth factor binding protein 1 concentration increased significantly from baseline with conjugated equine estrogen alone (44.1 +/- 6.0 vs 154 +/- 30 microg/L; P =.003). This rise was opposed by progestins of increasing androgenicity (medroxyprogesterone acetate, 130 +/- 26 microg/L; desogestrel, 100 +/- 16 microg/L; norethindrone, 78.0 +/- 12 microg/L; F = 12.5; P =.0015). Insulin-like growth factor binding protein 3 levels fell with conjugated equine estrogen, and this was reversed by progestins (conjugated equine estrogen, 2.17 +/- 0.13 mg/L; vs norethindrone and conjugated equine estrogen, 2.41 +/- 0.12 mg/L; F = 7.6; P =.01). Insulin-like growth factor binding protein 4 levels increased with conjugated equine estrogen with or without progestins, whereas insulin-like growth factor binding protein 2 levels were unchanged. CONCLUSIONS: Coadministration of androgenic progestins abrogates estrogen-related changes in circulating insulin-like growth factor I, insulin-like growth factor binding protein 1, and insulin-like growth factor binding protein 3. Such hormone replacement therapy-induced changes may have significant consequences for the development of cardiovascular disease and osteoporosis and implications for the use of insulin-like growth factor I in monitoring growth hormone replacement.

Preliminary report of impaired oestrogen receptor-alpha expression in bone, but no involvement of androgen receptor, in male idiopathic osteoporosis.

In western countries, osteoporosis affects at least 1 in 12 of all adult males and a third of osteoporotic men have idiopathic disease (MIO). Both oestrogen and testosterone are now known to be important to the male skeleton. As normal oestrogen levels have been found in younger MIO cases, it is hypothesized that, in bone, their responses to gonadal steroids may be defective, through impaired receptor expression. This study therefore compared oestrogen receptor (ER)-alpha and androgen receptor (AR) expression, by indirect immunofluorescence and semi-quantitative image analysis, in undecalcified fresh frozen bone sections from MIO patients (33-56 years), age-matched control men (n=7), and, for reference, ovarian steroid-replete (n=7) and -deficient women (n=6). In normal men, 23%+/-SEM 6% osteoblasts and 14%+/-SEM 2% osteocytes expressed ERalpha protein, similar to hormone-replete women. Although receptor expression decreased in hormone-deficient women, loss of ERalpha protein in MIO patients was more severe (1%+/-SEM 0.5% osteocytes, 2%+/-SEM 1% osteoblasts expressed receptor). In all four groups, there was little osteocyte AR expression, but in the women, a proportion of osteoblasts were receptor-positive. Deficient osteoblast and osteocyte ERalpha protein expression could explain the bone loss in these MIO patients.

Is a calculated total hip BMD of clinical use?

The diagnosis of osteoporosis is based on bone mass measurement. To avoid the errors associated with the measurement of spinal bone density the total hip has been accepted as the standard measurement site. This information is not available for many early measurements. We have assessed whether it is possible to derive clinically useful information about total hip bone mineral density (BMD) from measurements at other hip sites. The bone mass measurements of 46 patients participating in a current trial of therapy for osteoporosis were reviewed. The total hip BMD as directly measured was compared with that obtained from the formula: Total hip BMD = 0.48 x Neck BMD + 0.62 x Trochanteric BMD + 0.03. In 30 patients with follow-up data the rate of change in hip BMD over a year was also determined by both methods. In the pretreatment state there was good agreement between the two measures (r2 = 0.96, SEE 0.012 g/cm2). If the formula was used to compute a change in total hip BMD, the agreement between both methods remained good. However, the standard error of the estimate of the change represented 59% of the observed change. This indicates that the error associated with this estimate is too great to allow clinically meaningful conclusions to be drawn from calculated total hip BMD. We conclude that, whilst it may be possible to obtain reasonable point estimates of total hip BMD from other measures in the hip, these estimates are too imprecise to allow conclusions about change in BMD to be made.

Bone histomorphometry in adult patients with cystic fibrosis.

STUDY OBJECTIVE: Low bone mineral density is a common complication of cystic fibrosis (CF), and recent studies have implicated vitamin D insufficiency as a significant etiologic factor. The aim of this study was to establish whether there was bone biopsy evidence of vitamin D deficiency osteomalacia in patients with CF and to document the general histomorphometric characteristics of CF bone. PATIENTS AND METHODS: A retrospective descriptive and histomorphometric study of postmortem L2/L3 vertebral bone biopsy specimens was undertaken on tissue from 11 posttransplant CF patients and 4 nontransplanted CF patients. Control data were derived from postmortem bone specimens from 15 young adults. RESULTS: Bone from all CF patients was characterized by severe osteopenia in both trabecular and cortical bone. At the cellular level, there was decreased osteoblastic and increased osteoclastic activity. The reduction in osteoblastic activity was due to both a decrease in osteoblast number and a decrease in the biosynthetic potential of osteoblasts. The osteoclastic changes were due to an increase in the number of osteoclasts. The increase in osteoclasis and the uncoupling of osteoblastic and osteoclastic activity resulted in an increase in resorptive surfaces. Although there were few significant differences between the transplanted and nontransplanted CF groups, both cortical and trabecular bone mass tended to be lower after transplantation. None of the CF undecalcified biopsy specimens showed osteoid parameters characteristic of vitamin D deficiency osteomalacia. CONCLUSIONS: CF patients have an unusual and complex pattern of cellular changes within bone that are not typical of vitamin D deficiency osteomalacia.

Do men and women fracture bones at similar bone densities?

When the World Health Organization (WHO) guidelines for the definition of osteoporosis in postmenopausal women were identified similar proposals were not developed for men as there was insufficient evidence about the relationship between bone density and fracture in men. We have therefore examined the relationship between bone density and vertebral fracture in men and women attending for assessment of possible osteoporosis. Two hundred and sixty-four women (age 64 [SD 10] years) and 37 men (age 55 [10] years) were studied. Bone density was measured in the lumbar spine and femoral neck by dual-energy X-ray absorptiometry and expressed both as bone mineral density (BMD; g/cm2) and as T-scores. In both sexes there was a sigmoid relationship between the cumulative frequency of vertebral fracture and bone density at both sites. There was a linear relationship between the log odds of fracture and bone mass for both sexes and both sites (r = 0.97-0.99; p < 0.0001). The slope of these lines was significantly steeper for men than women. The BMD at which there was 50% risk of fracture was higher in men than women (0.908 vs 0.844 g/cm2). The difference between the slopes was similar when the bone mass was expressed as a T-score. However, the T-score associated with 50% prevalence of fracture was similar in the two sexes (F: -2.77 vs M: -2.60). We conclude that although there is a different relationship between bone density and fracture in the two sexes the current WHO definition of osteoporosis in postmenopausal women can be appropriately applied to men.

Corticosteroids do not alter the threshold for vertebral fracture.

Corticosteroid use is one of the most important secondary causes of osteoporosis. Generally, it has been believed that in addition to its effect on bone mineral density (BMD), it also causes an alteration in bone quality that means that fractures occur at a lower BMD than might be expected. To establish if this is the case, we have compared the relationship between BMD and vertebral fracture in patients receiving corticosteroids with that in patients who had never received such therapy. Information was gathered on those patients who had been referred to the participating centers and had both BMD measurements and lateral thoracolumbar radiographs. In all, 452 patients (391 female) were identified; of these 82 (63 female) were receiving corticosteroids. There was no significant difference in BMD between the patients on corticosteroids and those with other suspected causes of osteoporosis. Vertebral fractures were present in 53% of patients on steroids compared with 35% of those who had no such treatment (p = 0.0035). The fractures were more likely to be multiple in patients on corticosteroids (p = 0.0042). However, if the relationship between bone density and fracture is investigated by plotting the cumulative prevalence of fracture against the bone density, measured by T score, the median BMD for fractures actually was marginally lower in patients on steroids, -2.74 (95% confidence interval [CI], -2.77 to -2.70) compared with -2.65 (95% CI, -2.66 to -2.65) in those who had not received steroids. Our results fail to support the notion that the fracture threshold is altered in patients on long-term steroids and suggest that the same diagnostic criteria should be used for osteoporosis in patients whether or not they are taking corticosteroid therapy.

Hip fracture and bone histomorphometry in a young adult with cystic fibrosis.

A 25-yr-old male with cystic fibrosis sustained a fragility fracture of the left femoral neck, which required surgical correction. He had several risk factors for the development of low bone density and despite treatment with an oral bisphosphonate, his bone mineral density reduced further. The patient died 2 yrs after sustaining the fracture. Bone specimens obtained at post mortem demonstrated severe cortical and trabecular osteopenia, but the histological features were not typical of osteoporosis or osteomalacia. Osteoporosis is thought to be a common complication of cystic fibrosis. The novel histomorphometric appearances reported here suggest that the bone disease of cystic fibrosis may be more complex and possibly unique. Labelled bone biopsies are required to clarify the bone defect leading to low bone density in cystic fibrosis patients so that appropriate therapeutic strategies can be developed.

Low bone mineral density in adults with cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis have several risk factors for the development of low bone mineral density (BMD). To identify the prevalence and clinical correlates of low BMD in adult patients with cystic fibrosis, densitometry was performed in 151 patients (83 men) aged 15-52 years. METHODS: BMD was measured in the lumbar spine (L1-4) using dual energy x ray absorptiometry (DXA) and quantitative computed tomography (QCT). It was also measured in the proximal femur (total hip and femoral neck) using DXA, and in the distal and ultra distal forearm using single energy x ray absorptiometry (SXA). Biochemical markers of bone turnover, vitamin D levels, parathyroid hormone levels, and a variety of anthropometric variables were also assessed. RESULTS: The mean (SD) BMD Z score was -0.73 (0.85) in the distal forearm, -0.31 (0.92) in the ultra distal forearm, -1.21 (1. 18) in the lumbar spine using DXA, -0.56 (1.36) in the lumbar spine using QCT, -1.25 (1.30) in the femoral neck, and -1.01 (1.14) in the total hip. 34% of patients had a BMD Z score of -2 or less at one or more skeletal sites. Body mass index (0.527, p = 0.01), percentage predicted forced expiratory volume in one second (0.388, p = 0.01), and physical activity (0.249, p = 0.05) were positively related to the mean BMD Z score. Levels of C reactive protein (-0.328, p = 0. 01), parathyroid hormone (-0.311, p = 0.01) and biochemical markers of bone turnover (osteocalcin -0.261 and bone specific alkaline phosphatase -0.249, p = 0.05) were negatively related to the mean BMD Z score. Vitamin D insufficiency (25-hydroxyvitamin D <15 ng/ml) was prevalent (53/139 patients, 38%) despite supplementation with 900 IU vitamin D per day. CONCLUSIONS: Low bone density is prevalent in adult patients with cystic fibrosis. Current levels of vitamin D supplementation appear to be inadequate.