Development Of Bone Loss Research Articles

Bone mineral density and oxidative stress in adolescent girls with anorexia nervosa

Oxidative stress appears to be involved in the pathogenesis of osteoporosis-a serious complication of anorexia nervosa (AN). We evaluated the oxidative status in adolescent girls with AN and its potential relationship with bone mineral density (BMD). Girls with AN (n = 43) and age-matched healthy controls (n = 20) underwent anthropometric and BMD examination. Markers of bone turnover, oxidative stress, and antioxidant status were measured. Participants with AN and controls did not differ in BMD at the lumbar spine (p = 0.17) and total body less head BMD (p = 0.08). BMD at the total hip was lower (p < 0.001) in the AN group compared with the controls. Levels of antioxidant status markers-ferric reduction antioxidant power, total antioxidant capacity, and reduced and oxidized glutathione ratio (all p < 0.001)-were significantly lower, whereas those of advanced oxidation protein products (AOPP), fructosamines, and advanced glycation end products (AGEs) (all p < 0.001) were higher in AN patients than in healthy controls. BMD and bone turnover markers were positively correlated with antioxidant status markers, while they were negatively correlated with AOPP, fructosamines, and AGEs levels. Conclusion: This is the first study to assess a potential association between oxidative status and BMD in adolescents with AN. We demonstrated that in young girls, the imbalance of oxidative status and reduced BMD are concurrently manifested at the time of the diagnosis of AN. Disturbance of oxidative status could play a pathogenetic role in AN-associated decreased BMD. What is Known: • Osteoporosis is a serious complication of AN, and in affected adolescents may result in a permanent deficit in bone mass. • Oxidative and carbonyl stress may be involved in the development of bone loss. What is New: • Adolescents girls with AN have impaired antioxidant defense and increased oxidative damage to biomolecules. • Disturbance of oxidative status could affect bone loss and could contribute to decreased BMD in adolescent females with AN.

Pathogenic effects of anti-citrullinated protein antibodies in rheumatoid arthritis - role for glycosylation.

The identification in 1998 of the main antigenic substrate recognized by autoantibodies was a dramatic turning point in our understanding of rheumatoid arthritis (RA) biology. Now, two decades later, antibodies to citrullinated proteins are viewed no longer as mere biomarkers for RA, but also as major pathophysiological factors involved in the development of bone loss and joint pain. These pathogenic effects are ascribable to abnormal autoantibody glycosylation via a pathway involving the Th17T cells. In the future, abnormal autoantibody glycosylation may serve as a disease activity biomarker and suggest novel treatment strategies.

Strain-specific differences in the development of bone loss and incidence of osteonecrosis following glucocorticoid treatment in two different mouse strains

ObjectiveGlucocorticoids (GCs) are commonly prescribed as treatment for chronic inflammatory diseases. Prolonged use of GCs is a common cause of atraumatic osteonecrosis (ON) and secondary osteoporosis. Currently, there is no effective treatment for this disease; therefore, a reliable animal model would be useful to study both the pathology and novel treatment strategies for patients with the disease. The aim of this study was to establish a validated, reproducible model of GC-induced ON and bone loss in two different mouse strains (BALB/c and C57BL/6). MethodsSeven-week-old male BALB/c (n = 32) and male C57BL/6 mice (n = 32) were randomised into placebo or GC groups and treated with daily 4 mg/L oral dexamethasone in drinking water for 90 days. Study outcome measures included histologic assessment of ON of the distal femur, bone mass and mechanical strength of tibia and lumbar vertebral body, osteoclast number, biochemical measure of bone formation and bone marrow fat quantitation. ResultsGC-induced ON lesions were observed in the distal femur in 47% of the male BALB/c mice and 25% of the male C57BL/6 mice. GC treatment decreased the trabecular bone volume and serum pro-collagen type 1N-protease (P1NP) in BALB/c mice compared with the placebo (p < 0.05) and reduced tibial bone strength in both BALB/c and C57BL/6 mice. GC-treated BALB/c mice had significantly greater marrow fat levels compared to the placebo group. ConclusionGC-induced ON was more prevalent in the male BALB/c mice compared to the male C57BL/6 mice. GC treatment significantly reduced bone mass, bone formation measured by P1NP, bone strength and increased marrow fat levels in male BALB/c mice. Therefore, the use of male BALB/c mice strain is recommended for both diagnostic and therapeutic studies for the prevention and treatment of ON and bone loss following prolonged treatment with GCs. The Translational Potential of this ArticleGCs are commonly used to treat patients with various chronic inflammatory diseases, and this is associated with both the development of ON and bone loss. Our study confirmed that the BALB/c mouse strain treated for 90 days with GC may be useful for developing novel treatments for ON.

Early use of alendronate as a protective factor against the development of glucocorticoid-induced bone loss in childhood-onset rheumatic diseases: a cross-sectional study

BackgroundBisphosphonates are recommended for use as first-line therapy for the prevention and treatment of glucocorticoid-induced osteoporosis in adults. However, the appropriate usage of bisphosphonates for the prevention or treatment of glucocorticoid-induced osteoporosis in children remains unclear.MethodsWe performed a cross-sectional study to clarify the factors associated with the development of glucocorticoid-induced bone loss and osteoporosis in patients with childhood-onset rheumatic disease and to investigate the impact of the early use of alendronate. We recruited 39 patients with childhood-onset rheumatic disease who were evaluated to detect bone loss or osteoporosis at 3 months to 1.5 years after the initiation of treatment. The primary outcome of the study was the presence of bone loss or osteoporosis at the initial evaluation of the bone mineral density after at least 3 months of glucocorticoid therapy.ResultsBone loss and a history of fracture were found in 56 and 18% of the participants, respectively. Weekly oral alendronate therapy (median, 25.4 mg/m2) had been started by the time of the evaluation of osteoporosis in 46% of the participants and within 3 months after the start of glucocorticoid in 31% of the participants. There were no significant differences between the participants with bone loss (wBL group) and without bone loss (w/oBL group) in terms of gender, primary disease, or the age at the onset of primary disease. In terms of glucocorticoid use, there was no significant difference in the age at the start of glucocorticoid therapy, the length of glucocorticoid use, or the dose of glucocorticoids. The proportion of patients in the w/oBL group who received alendronate within 3 months after the start of glucocorticoid therapy was significantly greater than that in the wBL group. In the logistic regression analysis, only “alendronate therapy within 3 months after the start of glucocorticoid therapy” had a statistically significant effect on the development of bone loss (OR, 0.08; 95% CI, 0.02–0.43). The analysis did not reveal any factors associated with the development of osteoporosis.ConclusionsThe early use of alendronate may have a preventive effect against the development of bone loss in glucocorticoid-treated patients with childhood-onset rheumatic disease.

Directly measured free 25-hydroxy vitamin D levels show no evidence of vitamin D deficiency in young Swedish women with anorexia nervosa.

Anorexia nervosa (AN) is an eating disorder characterized by low fat mass complicated by osteoporosis. The role of circulating vitamin D in the development of bone loss in AN is unclear. Fat mass is known to be inversely associated with vitamin D levels measured as serum levels of total, protein-bound 25-hydroxyvitamin D, but the importance of directly measured, free levels of 25(OH)D has not been determined in AN. The aim of this study was to investigate vitamin D status, as assessed by serum concentrations of total and free serum 25(OH)D in patients with AN and healthy controls. In female AN patients (n=20), and healthy female controls (n=78), total 25(OH)D was measured by LC-MS/MS, and free 25(OH)D with ELISA. In patients with AN bone mineral density (BMD) was determined with DEXA. There were no differences between patients and controls in total or free S-25(OH)D levels (80±31 vs 72±18nmol/L, and 6.5±2.5 vs 5.6±1.8pg/ml, respectively), and no association to BMD was found. In the entire group of patients and controls, both vitamin D parameters correlated with BMI, leptin, and PTH. The current study did not demonstrate a vitamin D deficiency in patients with AN and our data does not support vitamin D deficiency as a contributing factor to bone loss in AN. Instead, we observed a trend toward higher vitamin D levels in AN subjects compared to controls. Measurement of free vitamin D levels did not contribute to additional information.

ICOS-Ligand Triggering Impairs Osteoclast Differentiation and Function In Vitro and In Vivo.

Osteoblasts, osteocytes, and osteoclasts (OCs) are involved in the bone production and resorption, which are crucial in bone homeostasis. OC hyperactivation plays a role in the exaggerated bone resorption of diseases such as osteoporosis, rheumatoid arthritis, and osteolytic tumor metastases. This work stems from the finding that OCs can express B7h (ICOS-Ligand), which is the ligand of the ICOS T cell costimulatory molecule. Because recent reports have shown that, in endothelial, dendritic, and tumor cells, B7h triggering modulates several activities of these cells, we analyzed the effect of B7h triggering by recombinant ICOS-Fc on OC differentiation and function. The results showed that ICOS-Fc inhibits RANKL-mediated differentiation of human monocyte-derived OC-like cells (MDOCs) by inhibiting the acquirement of the OC morphology, the CD14- cathepsin K+ phenotype, and the expression of tartrate-resistant acid phosphatase, OSCAR, NFATc1, and DC-STAMP. Moreover, ICOS-Fc induces a reversible decrease in the sizes of cells and nuclei and cathepsin K expression in mature MDOCs. Finally, ICOS-Fc inhibits the osteolytic activities of MDOCs in vitro and the development of bone loss in ovariectomized or soluble RANKL-treated mice. These findings open a novel field in the pharmacological use of agonists and antagonists of the ICOS-B7h system.

Spontaneous Alveolar Bone Loss Development by Alloxan-induced Diabetes Mellitus in Rats

Diabetes mellitus is associated with the occurrence and severity of alveolar bone loss. This study evaluated the effect of alloxan-induced diabetes mellitus on the percentage of remaining periodontal bone support (PBS) and periodontal bone loss (PBL) in adult rats. Twenty female rats were injected with alloxan diluted at 0.2% in a 0.05 M citrate buffer, pH 4.5 (150 mg/kg, i.p.) and eight of them became diabetic. The glycaemic indexes were investigated weekly. After 42 days, the rats were euthanized and left mandibles were radiographed to measure the PBS. The same left mandibles were defleshed and stained and PBL was evaluated morphometrically by measuring the distance between the cementoenamel junction and alveolar bone crest. The comparison between the diabetic and control groups showed that the induced diabetes provoked statistically lower percentage of PBS and higher periodontal bone destruction (p<0.05). In conclusion, the induction of diabetes mellitus in adult rats may cause alveolar bone loss and reduce the remaining periodontal bone support.

Bone mineral density and vitamin D status in Parkinson’s disease patients

Bone loss is more common in Parkinson's disease (PD) than in the general population. Several factors may be involved in the development of bone loss, including malnutrition, immobilization, low body mass index, decreased muscle strength, vitamin D deficiency and medication use. This study investigates the prevalence of osteoporosis and possible risk factors associated with bone loss in early stage PD. In 186 PD patients (Hoehn and Yahr stage 1-2.5, mean age 64.1years, 71% men) bone mineral density (BMD) measurements were performed with DEXA. T- and Z-scores were calculated. Univariate linear regression analysis was performed to identify variables that contributed to BMD. 25-OH-vitamin D status of PD patients was compared with 802 controls (mean age 63.3years, 50% men) using linear regression analysis. Osteoporosis (11.8%) and osteopenia (41.4%) were common in PD patients. Mean Z-score for the hip was 0.24 (SD 0.93), and for the lumbar spine 0.72 (SD 1.91). Female gender, low weight, and low 25-OH-vitamin D were significantly correlated with BMD of the hip and lumbar spine. PD patients had lower 25(OH)D serum levels than controls (B=-10, p=0.000). More than half of the patients with early stage PD had an abnormal BMD. Female gender, low weight, and low vitamin D concentration were associated with bone loss. Furthermore, vitamin D concentrations were reduced in PD patients. These results underscore the importance of proactive screening for bone loss and vitamin D deficiency, even in early stages of PD.

Evaluation of bone mineral density in Turkish children with severe haemophilia A: Ankara hospital experience

This study was conducted to understand the pathogenetic mechanisms that are involved in the development of bone loss in children with severe haemophilia A (HA). Fourty-four children with severe HA and 40 age- and gender-matched healthy control subjects were enrolled in this study. Markers of bone remodelling and osteoclast regulation including serum bone specific alkaline phosphatase, parathormone, 25-hydroxy-vitamin D(3) (25HOvitD(3)), osteocalcin and calcitonin levels were studied. Bone mineral density (BMD) was also studied in all children. The measurement of markers of bone remodelling and osteoclast regulation suggested increased osteoclast-mediated resorption activity in children with severe HA. Although serum parathormone levels were significantly increased, serum 25HOvitD(3) and osteocalcin levels were significantly reduced. BMD was significantly reduced in severe haemophilics compared with healthy controls. There was also significant inverse correlation between BMD z-score and total joint scores, and insignificant inverse correlation between BMD z-score and single joint scores. There were also significant inverse correlation between 25HOvitD(3) and osteocalcin levels and total joint scores. Children with severe HA could have significantly reduced BMD, compared with gender- and age-matched healthy control subjects. Our results of the markers of bone remodelling and osteoclast regulation suggested that increased osteoclast-mediated resorption and decreased osteoblastic activity in children with severe HA. All children with severe HA should be routinely screened in terms of BMD.

Early decrements in bone density after completion of neoadjuvant chemotherapy in pediatric bone sarcoma patients

BackgroundBone mineral density (BMD) accrual during childhood and adolescence is important for attaining peak bone mass. BMD decrements have been reported in survivors of childhood bone sarcomas. However, little is known about the onset and development of bone loss during cancer treatment. The objective of this cross-sectional study was to evaluate BMD in newly diagnosed Ewing's and osteosarcoma patients by means of dual-energy x-ray absorptiometry (DXA) after completion of neoadjuvant chemotherapy.MethodsDXA measurements of the lumbar spine (L2-4), both femora and calcanei were performed perioperatively in 46 children and adolescents (mean age: 14.3 years, range: 8.6-21.5 years). Mean Z-scores, areal BMD (g/cm2), calculated volumetric BMD (g/cm3) and bone mineral content (BMC, g) were determined.ResultsLumbar spine mean Z-score was -0.14 (95% CI: -0.46 to 0.18), areal BMD was 1.016 g/cm2 (95% CI: 0.950 to 1.082) and volumetric BMD was 0.330 g/cm3 (95% CI: 0.314 to 0.347) which is comparable to healthy peers. For patients with a lower extremity tumor (n = 36), the difference between the affected and non-affected femoral neck was 12.1% (95% CI: -16.3 to -7.9) in areal BMD. The reduction of BMD was more pronounced in the calcaneus with a difference between the affected and contralateral side of 21.7% (95% CI: -29.3 to -14.0) for areal BMD. Furthermore, significant correlations for femoral and calcaneal DXA measurements were found with Spearman-rho coefficients ranging from ρ = 0.55 to ρ = 0.80.ConclusionsThe tumor disease located in the lower extremity in combination with offloading recommendations induced diminished BMD values, indicating local osteopenia conditions. However, the results revealed no significant decrements of lumbar spine BMD in pediatric sarcoma patients after completion of neoadjuvant chemotherapy. Nevertheless, it has to be taken into account that bone tumor patients may experience BMD decrements or secondary osteoporosis in later life. Furthermore, the peripheral assessment of BMD in the calcaneus via DXA is a feasible approach to quantify bone loss in the lower extremity in bone sarcoma patients and may serve as an alternative procedure, when the established assessment of femoral BMD is not practicable due to endoprosthetic replacements.

Evaluation of Bone Disease in Morbidly Obese Women After Gastric Bypass and Risk Factors Implicated in Bone Loss

In patients undergoing gastric bypass, massive weight loss and impairment of calcium intake and absorption in the duodenum and proximal jejunum may increase the risk of bone mass loss and fractures. However, few data are available regarding the impact of this surgery on the skeleton. The aim of our study was to examine the skeletal changes in a cohort of morbidly obese Caucasian women during the first year after gastric bypass and to analyse the factors implicated in the development of bone loss. Sixty-two morbidly obese white women aged 45.3 +/- 8.9 years were studied. Anthropometric measurements, bone mineral density (BMD) screening using dual-energy X- ray absorptiometry and plasma determinations of calcium, phosphorus, parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH) D(3)] and insulin-like growth factor-I (IGF-I) were made prior to and 12 months after surgery. A year after surgery, BMD significantly decreased at the femoral neck (10.2 +/- 5.7%) and at the lumbar spine (3.2 +/- 4.4%). In the follow-up, 16.1% of women had osteopenia at the femoral neck and 19.3% at the lumbar spine, and 1.6% developed osteoporosis at the lumbar spine. Patients with bone disease were significantly older; the percentage of women with menopause was greater in this group and had lower initial and final values of lean mass. However, no differences in body mass index, weight loss, fat mass, calcium, PTH, 25(OH) D(3) or IGF-I values were found between groups. In the logistic regression analysis, lean mass 12 months after surgery and menopause were found to be the main determinants of osteopenia after adjusting for age with odds ratios of 0.82 and 9.13, respectively. There is a significant BMD loss at the femoral neck and lumbar spine a year after gastric bypass. Menopausal patients and those with greater lean mass loss are at greater risk and, consequently, should be closely followed up with periodic densitometries.

Follicle-stimulating hormone does not directly regulate bone mass in human beings: evidence from nature

To evaluate the effect of FSH levels in the development of human osteoporosis. Case-series study. Gynecology department in a teaching hospital. A total of 8 women diagnosed with Kallman syndrome (KS) were compared with 11 with Turner syndrome and 11 with pure gonadal dysgenesia (GD, karyotype 46,XX). We assessed the pituitary-gonadal axis, bone turnover markers, bone mass, and patient characteristics. Bone mineral density as assessed by dual-energy X-ray absorptiometry, plasma FSH, LH, E(2), osteocalcin (BGP), and urinary type I collagen cross-linked N-telopeptide. Other biochemical markers included 25-hydroxyvitamin D, as well as parathyroid hormone and urine concentration of calcium and creatinine. In girls with Turner syndrome and GD, FSH (64.03 +/- 29.2 and 90.08 +/- 22.41 mIU/mL, respectively) and LH (45.29 +/- 11.90 and 48.83 +/- 12.44 mIU/mL, respectively) levels were significantly higher compared with those observed in girls with KS (FSH: 1.87 +/- 0.64 and LH: 1.02 +/- 0.57), whereas no differences were detected in E(2) or bone marker levels. Bone mineral density correlated positively with FSH levels but not with E(2); however, after adjusting for previous growth-hormone therapy, these differences were not found. In addition, bone mineral density in spine and total hip was significantly lower in patients with KS. Follicle-stimulating hormone does not appear to have a major role in the development of bone loss in young women with primary amenorrhea.

Posttransplant bone disease

Abstract Kidney transplantation reverses some of the disturbances of mineral and bone metabolism. However, the reversal or degree of improvement is often incomplete. The well-documented bone loss, especially in the early posttransplant period, contributes to an increased incidence of fractures in kidney transplant recipients. To better understand the mechanism of bone loss posttransplant, we need to take in consideration both bone quantity (density) and quality (bone microarchitecture, turnover rate). In addition to bone density, which is a measure of bone quantity, there are other invasive and noninvasive tools that provide information about the bone architecture and turnover and may be helpful in evaluating kidney transplant recipients at risk of fractures. There are several factors that contribute to the development of bone loss in the posttransplant period. Among these, the use of glucocorticoids, as part of the posttransplant immunosuppressive regimen, remains the single most important risk factor for bone loss post–kidney transplant. Interventions for evaluation and management of bone disease posttransplant are described and discussed. Some of these measures have been shown to increase bone density, but so far, none have demonstrated an ability to reduce the fracture incidence.

Effect of High Molecular Weight Water-Soluble Chitosan on the Trabecular Bone and Thickness in Ovariectomized Rats

High molecular weight water-soluble chitosan(WSC), having an average molecular weight of 300,000 Da and a degree of deacethylation over 90%, can be produced using a simple multi-step membrane separation process. In this study, the trabecular bone area and thickness in ovariectomized(OVX) rats decreased by almost 50% from those in sham-operated rats. WSC was evaluated for inhibition of the progress of bone loss induced by OVX rats. We measured bone histomorphometry in sham, OVX or WSC-administered OVX rats. From light microscopic analyses, a porous or erosive appearances were observed on the surface of trabecular bone of tibia in OVX rats, whereas those of the same bone in sham-operated rats were composed of fine particles. The trabecular bone area and trabecular thickness in OVX rats decreased by 50% from those in sham rats, these decreases were completely inhibited by administration of WSC at a concentration of 15 mg/kg/daily for 7 weeks. In this study, the mechanical strength in femur neck was significantly enhanced by the treatment of WSC for 7 weeks. In OVX rats, free T3 was normal in all cases, whereas free T4 was significantly increased. Although there was no difference between OVX and WSC-administered rats in T3 level, we have found significant difference between them in T4 level. These results strongly suggest that WSC is effective in preventing the development of bone loss induced by OVX in rats.

Placenta Hominis Protects Osteoporosis in Ovariectomized Rats

In China, Japan, and Korea, placenta hominis extracts (PHEs) are used clinically for the treatment of osteoporosis. The anti-osteoporotic effect of PHEs was studied. The trabecular bone area and thickness in OVX rats decreased by 50% from those in sham-operated rats; these decreases were completely inhibited by administration of PHEs for 7 weeks. Osteoclast numbers and the osteoblast surface were enhanced in OVX rats, but PHEs had no effect on these phenomena. Serum phosphorus and alkaline phosphatase in OVX rats increased compared to those in sham-operated rats, but the increases were not affected by the administration of PHEs. Thyroxine (T4) level was stimulated in OVX rats. The extracts inhibited the T4 level in the OVX rats. These results strongly suggest that PHEs be effective in preventing the development of bone loss induced by OVX in rats.

Osteoporosis in Sickle Cell/β-Thalassemia Is Primarily Caused by an Imbalance at the RANKL/OPG Pathway.

Bone involvement is the commonest clinical manifestation of sickle cell disease (SCD) including chronic disorders, such as osteopenia/osteoporosis. The aim of the present study is to evaluate the bone mineral density (BMD) of patients with SCD/β-thalassemia (S/β-th) in parallel with markers of bone turnover in an attempt to better understand the pathophysiology of bone loss in these patients. We studied 52 patients with S/β-th (23M/29F; median age 40 y). The BMD of the lumbar spine (L) and femoral neck (F) was evaluated by DEXA. Bone remodeling was assessed using the following serum indices: (a) bone resorption markers [C-telopeptide of type-I collagen (CTX), tartrate-resistant acid phosphatase isoform-5b (TRACP-5b)], (b) bone formation markers [bone-alkaline phosphatase (bALP), osteocalcin (OC), and C-terminal propeptide of collagen type-I (CICP)], and (c) osteoclast stimulating factors [soluble receptor activator of nuclear factor κB ligand (sRANKL), and osteoprotegerin (OPG)]. Moreover, all patients had a thorough evaluation of their renal function (creatinine clearance, and cystatin-C serum levels), bone marrow expansion (soluble transferin receptors, sTfR), serum erythropoietin (Epo) and parathyroid hormone (PTH) levels. The same biochemical parameters were also determined in 25 age- and gender-matched controls. According to WHO criteria, 17 patients (32.6%; 8M/9F, median age 45 y) had osteopenia or osteoporosis (median L/T-score: −2.26; L/BMD: 0.9 g/cm2; F/T-score: −1.86; F/BMD: 0.68 g/cm2). In contrast, 30 patients (57.6%; 12M/18F, median age 40 y) had osteosclerosis (median L/T-score: +3.15; L/BMD: 1550.5 g/m2; F/T-score: +0.52; F/BMD: 1113.5 g/cm2). Renal function, Epo, Hb and sTfR levels and the number of crises/year were similar between both groups. All patients displayed increased levels of OPG, bALP, and CICP compared with controls (p<0.02). CTX levels in the osteosclerotic patients were significantly lower than those of both controls (p<0.0001) and osteopenic/osteoporotic patients (p<0.003); this finding implies a diminished bone resorption. Moreover, bALP and PTH in the osteopenia/osteoposis group were higher than those of the osteosclerosis group (p<0.01, and <0.03, respectively). BMD of the osteopenic/osteoporotic patients showed a strong correlation with OPG and CTX levels (p=0.01, and 0.008, respectively). This result, in combination with the significant correlations observed between OPG and sRANKL, TRACP-5b, and bALP in these patients suggests that osteopenia/osteoporosis in S/β-th results mainly from an imbalance at the RANKL/OPG axis. Conversely, considering the absence of correlation between BMD and sTfR in the same patient group, the potential contribution of bone marrow expansion in the development of osteopenia appears much weaker. No correlation between BMD and bone indices observed in osteosclerotic group. In conclusion, this study suggests that the development of bone loss in S/β-th patients is mainly due to an imbalance in RANKL/OPG pathway. Novel agents that target this system, as well as bisphosphonates, maybe useful in the management of this common SCD complication.

Bone Densitometry in Premenopausal Women: Synthesis and Review

Abstract Bone loss prior to menopause is being increasingly identified in women. Clearly, low bone mineral density (BMD) is a significant risk factor for fracture in the estrogen-deficient female postmenopause. The significance of low bone density prior to menopause needs to be addressed. Low bone density in the premenopausal female may reflect attainment of a lower peak bone mass. It may also be secondary to progressive bone loss following achievement of peak bone density. The etiology of low bone density in the premenopausal female needs to be clarified with meticulous exclusion of secondary causes of bone loss. Menstrual status is an important determinant of peak bone mass as well as the development of bone loss in women prior to the onset of menopause. Subclinical decreases in circulating gonadal steroids may be associated with a lower peak bone mass as well as progressive bone loss in otherwise reproductively normal women. Elevations of follicle-stimulating hormone (FSH) of greater than 20 miu/L are associated with evidence of increased bone turnover marker activity and correlate with progressive bone loss in perimenopausal women. This transitional period requires further study with respect to the magnitude of bone loss experienced and the potential benefits of antiresorptive therapy. Detailed assessment of menstrual status is necessary in the evaluation of low bone density in premenopausal women. The majority of the cross-sectional and longitudinal studies completed evaluating BMD in the premenopausal years suggest that minimal bone loss does occur prior to menopause after attainment of peak bone mass. The magnitude of premenopausal bone loss, however, is controversial and may be site-dependent. More rapid rates of bone loss are seen in the transitional period beginning 2–3 yr prior to the onset of menopause. Prospective data are needed to understand further the relationship between BMD and fracture in the premenopausal period. Women with steroid-induced bone loss as well as other secondary causes of osteoporosis respond to antiresorptive therapy with documented improvements in BMD. Biomarkers can identify perimenopausal women with increased bone turnover. Lifestyle modification can improve BMD in the pre- and the perimenopausal period. Antiresorptive therapy has not been evaluated in pre- or perimenopausal women with low BMD in the absence of secondary causes of osteoporosis. As new treatment options are evaluated and become available, biomarker assessment may be of value in identifying women at risk of fracture. This paper provides a review of the literature and recommendations with respect to management of low bone density in the premenopausal female.

Prevention of Bone Loss in Ovariectomized Rats: The Effect of Salvia miltiorrhiza Extracts

The preventive effect of Salvia miltiorrhiza extracts (SMEs) on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. We measured body weight and bone histomorphometry in sham, OVX or SMEs‐administered OVX rats. From light microscopic analyses, a porous or erosive appearances were observed on the surface of trabecular bone of tibia in OVX rats, whereas those of the same bone in sham rats and in SMEs‐administered rats were composed of fine particles. The trabecular bone area and trabecular thickness in OVX rats decreased by 50% from those in sham rats, these decreases were completely inhibited by administration of SMEs for 7 weeks. In this study, the mechanical strength in femur neck was significantly enhanced by the treatment of SMEs for 7 weeks. In OVX rats, free T3 was normal in all cases, whereas free T4 was significantly increased. Although there was no difference between OVX and SMEs‐administered rats in T3 level, we have found significant difference between them in T4 level. These results strongly suggest that SMEs are effective in preventing the development of bone loss induced by OVX in rats.

Inhibitory Activity of Drynariae rhizoma Extracts on Cathepsin Having Bone Resorption Activity

Effects of traditional Korean (Hanbang) medicine, Drynariae rhizoma (DR), on the protease activity of bone loss‐initiation in rats and mice were investigated. Ethanol extracts‐DR (EE‐DR) and water extracts‐DR (WE‐DR) were identified as potent inhibitor of cathepsins K and L. The original WE‐DR inhibits cathepsins K and L with IC50 values of 3.7 µg/ml and 4.5 µg/ml, respectively. EE‐DR was more potent than that of WE‐DR, because the inhibitions of cathepsin K and L increased to 0.5 µg/ml and 0.8 µg/ml, respectively. The EE‐DR was proved to be the most potent. EE‐DR was found to be a potent inhibitor of cathepsins K with a Ki value of 5.0 µg/ml for cathepsin K. The activity was increased by 10‐fold when the assay is performed in the presence of glutathione at pH 7.0, which favors the formation of a GSH thiolate anion. Thus, it is suggested that this increase in potency is probably due to an enhanced chemical reactivity of the extract mixtures toward the thiolate of the active site of the enzyme. WE‐DR exhibited time‐dependet inhibition which allowed us to determine the association and dissociation rate constants with cathepsin K. Finally, EE‐DR inhibits bone resorption in an in vitro assay involving mouse osteoclasts and bovine bone with an IC50 value of 70 µg/ml. WE‐DR represents a new herbal formulation inhibiting cathepsin K and L activity and proteolysis of bone collagen. These results strongly suggest that DR is effective for preventing the development of bone loss induced by cathepsin K. This result also suggested that the DR is effective for bone resorptive action in bone cells.

Antiosteoporotic activity of Dae-Bo-Won-Chun in Ovariectomized rats

The preventive effect of the herbal formulation, "Dae-Bo-Won-Chun" (DBWC), on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. From light microscope analyses, porous or erosive appearances were observed on the surface of trabecular bone of tibia in ovariectomized rats, whereas those of the same bone in sham-operated rats were composed of fine particles. The trabecular bone area and trabecular thickness in ovariectomized rats decreased by 50% from those in sham-operated rats, these decreases were completely inhibited by administration of DBWC at a concentration of 10 mg/kg per day for 7 weeks. The mechanical strength of the neck of the femur was decreased by ovariectomy, and this was significantly suppressed by the administration of DBWC. Serum phosphorus, alkaline phosphatase and thyroxine levels in ovariectomized rats increased compared with those in sham-operated rats, and increases were completely inhibited by the administration of DBWC. These results strongly suggest that DBWC is effective in preventing the development of bone loss induced by ovariectomy in rats.