Insulin-like growth factor-1 is associated with bone formation markers, PTH and bone mineral density in healthy premenopausal women

Bone mass in Saudi women aged 20-40 years: the association with obesity and vitamin D deficiency

This study describes that low bone density is prevalent in premenopausal Saudi women, especially women of normal weight and vitamin D deficiency. Although BMD is higher in obese young women, this may not be beneficial later in life in conjunction with persistent vitamin D deficiency.

INTRODUCTION

Not attaining peak bone mass is one crucial factor contributing to the risk of developing osteoporosis and suffering fractures in later life. The objectives of this study were to describe the normal range of bone mineral density (BMD) and bone mineral content (BMC) in premenopausal Saudi women in relation to obesity and vitamin D insufficiency.

METHODS

A cross-sectional study involving 312 healthy Saudi women aged 20-40. All women were clinically examined. BMD (g/cm²) and BMC (g) assessed at total body (TB), femoral neck (FN) and lumbar spine (LS) were performed using dual-energy X-ray absorptiometry (DXA). Obesity was defined as BMI ≥ 30 kg/m² and vitamin D deficiency defined as 25(OH)D < 50 nmol/L.

RESULTS

Almost half of the studied women were obese, and the majority (86.2%) were deficient in vitamin D. Mean BMD in TB 1.060 ± 0.091, FN 0.918 ± 0.153 and LS 1.118 ± 0.123 g/cm², while TB-BMC 2077 ± 272 g. When classified by BMI, the proportion with low bone density was 2-3 times higher among the normal weight compared to the obese women, p < 0.001. In the cohort overall, ~ 19% of these young premenopausal women had osteopenia or osteoporosis at the femoral neck, but 26% in normal weight, vitamin D deficient women.

CONCLUSION

This study shows low bone density in premenopausal Saudi women, particularly those with normal weight. While obesity appears to confer some protection against vitamin D deficiency at this age, this is assumed to change in later life.

Insulin-like growth factor-1 positively associated with bone formation markers and creatine kinase in adults with general physical activity

BACKGROUND

The Insulin-like growth factor-1 (IGF-1) is primarily synthesized by hepatocytes in a growth hormone (GH)-dependent manner, it is also produced by bone and muscle. The effects of exercise on the associations between IGF-1 levels and bone turnover markers (BTM) were found in the previous studies. However, the associations between the levels of IGF-1 and BTM, liver function tests, and skeletal muscle markers in adults with general physical activity were not clear.

METHODS

Ninety-four participants were recruited from healthy survey. Blood samples were collected to analyze the levels of IGF-1, total protein (TP), albumin (Alb), total bilirubin (T-Bil), direct bilirubin (D-Bil), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bone alkaline phosphatase (BALP), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine (CRTN), and glucose. Urine samples were collected to analyze the CRTN and deoxypyridinoline (Dpd) levels.

RESULTS

The positively significant associations were found between the IGF-1 levels and the levels of ALP, BALP, and CK, respectively. No significant associations were found between the IGF-1 levels and the levels of TP, Alb, A/G, T-Bil, D-Bil, AST, ALT, LDH, glucose, urinary CRTN, urinary Dpd, and Dpd/CRTN ratios, respectively.

CONCLUSION

The serum IGF-1 levels associated with the levels of skeletal muscle and bone formation markers (BFM), not the bone resorption markers under general physical activity in the healthy adults. The physician needs to consider the effects of bone formation and skeletal muscle markers on the IGF-1 levels in the management of IGF-1-related disorders.

Food Versus Pharmacy: Assessment of Nutritional and Pharmacological Strategies to Improve Bone Health in Energy-Deficient Exercising Women

PURPOSE OF REVIEW

The review aims to summarize our current knowledge surrounding treatment strategies aimed at recovery of bone mass in energy-deficient women suffering from the Female Athlete Triad.

RECENT FINDINGS

The independent and interactive contributions of energy status versus estrogen status on bone density, geometry, and strength have recently been reported, highlighting the importance of addressing both energy and estrogen in treatment strategies for bone health. This is supported by reports that have identified energy-related features (low body weight and BMI) and estrogen-related features (late age of menarche, oligo/amenorrhea) to be significant risk factors for low bone mineral density and bone stress injury in female athletes and exercising women. Nutritional therapy is the recommended first line of treatment to recover bone mass in energy-deficient female athletes and exercising women. If nutritional therapy fails after 12 months or if fractures or significant worsening in BMD occurs, pharmacological therapy may be considered in the form of transdermal estradiol with cyclic oral progestin (not COC).

Bone mineral density and breast cancer risk: Results from the Vorarlberg Health Monitoring & Prevention Program and meta-analysis

We investigated the association between bone mineral density (BMD) and breast cancer risk in a large prospective cohort and quantified the evidence in a meta-analysis of prospective studies.

Baseline BMD has been measured by dual energy X-ray absorptiometry (DXA, N = 1418). Data on medication and lifestyle has been collected by questionnaire. Cox proportional Hazards models were applied to calculate Hazard Ratios for breast cancer. In addition, a meta-analysis on categorical and dose-response values including the current results has been performed applying random-effects models.

During mean follow-up of 16.3 (SD 3.3) years of 1380 women (mean age 55.5 ± 6.3 years), 52 cases of invasive breast cancer were identified. We found no statistically significant association of BMD with breast cancer risk (per one z-score increase, HR 0.91, 95% CI 0.67–1.23).

In the meta-analysis, however, breast cancer risk increased by 15% and 16% per 0.1 g/m² increase in BMD at the lumbar spine (95% CI 0.99–1.33) and at the femoral neck (95% CI 1.02–1.32), respectively. Compared to the lowest, the HRs for breast cancer were statistically significant for the highest BMD category, i.e. 1.49 (95% CI 1.04–2.13) at the lumbar spine and 1.66 (95% CI 1.26–2.18) at the femur.

We found no association between BMD (DXA) and breast cancer risk in our cohort. However, overall the present meta-analysis extends and confirms the statistically significant association between increasing BMD and increased breast cancer risk.

•

In the VHM&PP BMD (DXA) was not associated with breast cancer risk.

•

A meta-analysis showed a positive association between BMD and breast cancer risk in postmenopausal women.

•

Per 0.1 g/m² increase in BMD breast cancer risk increased by 15% at the lumbar spine and 16% at the femoral neck.

Effect of Surgery Versus Observation: Skeletal 5-Year Outcomes in a Randomized Trial of Patients With Primary HPT (the SIPH Study)

Mild primary hyperparathyroidism (PHPT) is known to affect the skeleton, even though patients usually are asymptomatic. Treatment strategies have been widely discussed. However, long-term randomized studies comparing parathyroidectomy to observation are lacking. The objective was to study the effect of parathyroidectomy (PTX) compared with observation (OBS) on bone mineral density (BMD) in g/cm² and T-scores and on biochemical markers of bone turnover (P1NP and CTX-1) in a prospective randomized controlled study of patients with mild PHPT after 5 years of follow-up. Of 191 patients with mild PHPT randomized to either PTX or OBS, 145 patients remained for analysis after 5 years (110 with validated DXA scans). A significant decrease in P1NP (p < 0.001) and CTX-1 (p < 0.001) was found in the PTX group only. A significant positive treatment effect of surgery compared with observation on BMD (g/cm² ) was found for the lumbar spine (LS) (p = 0.011), the femoral neck (FN) (p < 0.001), the ultradistal radius (UDR) (p = 0.042), and for the total body (TB) (p < 0.001) but not for the radius 33% (Rad33), where BMD decreased significantly also in the PTX group (p = 0.012). However, compared with baseline values, there was no significant BMD increase in the PTX group, except for the lumbar spine. In the OBS group, there was a significant decrease in BMD (g/cm² ) for all compartments (FN, p < 0.001; Rad33, p = 0.001; UDR, p = 0.006; TB, p < 0.001) with the exception of the LS, where BMD was stable. In conclusion, parathyroidectomy improves BMD and observation leads to a small but statistically significant decrease in BMD after 5 years. Thus, bone health appears to be a clinical concern with long-term observation in patients with mild PHPT. © 2017 American Society for Bone and Mineral Research.

Bone mineral density in people living with HIV: a narrative review of the literature

Bone health status is largely absent in South Africa, the main reasons being the absence and cost-effectiveness of specific screening equipment for assessing bone mineral density (BMD). Various risk factors seem to play a role, some of which can be modified to change bone health status. Urbanisation is also a public health concern. Changing nutritional, as well as social behaviour, play integral roles in the prevalence and incidence of decreased BMD. Furthermore, human immunodeficiency virus (HIV) specifically, has a negative impact on BMD and although highly active antiretroviral therapy increases the prognosis for HIV-infected individuals, BMD still seem to decrease further. Dual energy X-ray absorptiometry is considered the gold standard for BMD assessment; however, recent developments have provided more cost-effective screening methods, among which heel quantitative ultrasound appears to be the most widely used in resource limited countries such as South Africa.

Z-score discordance and contributing factors in healthy premenopausal women with low bone mineral density: the Korean National Health and Nutrition Examination Survey 2008-9

The premenopausal period is important for bone health and prevention of future fractures, but measuring bone mineral density (BMD) at only one site may not be sufficient to determine therapeutic strategies for low BMD in premenopausal women due to the presence of Z-score discordance. In this study, we investigated Z-score discordance in addition to contributing factors of idiopathic low BMD in healthy premenopausal Korean women. We studied 3003 premenopausal women aged 18-50 years, without secondary causes for low BMD and history of fragility fracture, who had participated in the Fourth Korean National Health and Nutrition Examination Surveys (2008-2009). Low body mass index (BMI), low vitamin D level, and low body muscle mass were associated with low BMD even in premenopausal women. Risk factors differed depending on the anatomic site. Low BMI and low vitamin D level were risk factors for low femoral neck BMD (FN-BMD), but not for low lumbar spine BMD (LS-BMD). Only total muscle mass had a slight effect on low LS-BMD. Z-score discordance was much higher than expected, in 75 and 73.8 % of the low LS-BMD and low FN-BMD groups, respectively. Our findings suggest the need to consider BMD discordance in premenopausal women and also to provide information on correctable factors affecting low BMD in younger populations. Long-term follow-up is needed to evaluate the possible effect of Z-score discordance on the prognosis of osteoporosis and subsequent fracture risk.

Long-term glucocorticoid effect on bone mineral density in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

INTRODUCTION

Patients with 21-hydroxylase deficiency (21OHD) assume a lifelong glucocorticoid (GC) therapy. Excessive GC treatment increases the risk of osteoporosis and bone fractures, even though the role of substitutive therapy is not fully established: we analyzed the effect of GC dose on bone metabolism and bone mineral density (BMD) over time in patients with 21OHD.

METHODS

We studied bone metabolism markers and BMD in 38 adult patients with 21OHD (19-47 years, 24 females and 14 males) and 38 matched healthy control. In 15 patients, BMD data were available at both baseline and after a long-term follow-up.

RESULTS

BMD was lower in patients than in controls at lumbar spine (0.961±0.1g/cm(2) vs 1.02±0.113g/cm(2), P=0.014) and femur neck (0.736±0.128g/cm(2) vs 0.828±0.103g/cm(2), P=0.02); otherwise, after height correction, only femoral neck BMD was lower in patients (0.458±0.081g/cm(2) vs 0.498±0.063g/cm(2), P=0.028). In those 21OHD subjects with at least 10 years follow-up, we observed an increase in lumbar BMD (P=0.0429) and a decrease in femur neck BMD values (P=0.004). Cumulative GC dose was not related to bone metabolism or BMD. No patient experienced clinical fragility fractures.

CONCLUSIONS

BMD values are decreased in patients with 21OHD, which are in part explained by decreased height, but not by the dose of glucocorticoids. Nevertheless, bone status should be carefully monitored in patients with 21OHD.

The association between circulating IGF1, IGFBP3, and calcium: results from NHANES III

BACKGROUND

Despite mounting evidence linking both calcium and IGF1, there is a lack of studies investigating any association between circulating levels of IGF1 and serum calcium.

METHODS

Serum calcium, IGF1, and IGF-binding protein 3 (IGFBP3) were measured for 5368 participants in NHANES III. We calculated multivariable-adjusted geometric means of serum concentrations of IGF1, IGFBP3, and IGF1/IGFBP3 by categories of calcium (lowest 5% (<1.16 mmol/l), mid 90%, and top 5% (≥1.31 mmol/l)). We also performed stratified analyses by sex, age, ethnicity, BMI, serum levels of vitamin D, and bone mineral density (BMD).

RESULTS

Overall, we found that circulating calcium was positively associated with circulating levels of IGF1 and IGFBP3, but not their molar ratio (i.e., geometric mean of IGF1 by increasing calcium categories: 237.63, 246.51, and 264.22 ng/nl; Ptrend: 0.43; Pfirst vs third category: 0.01). In particular, these associations were observed in women, people aged <60, non-Hispanic whites, those with vitamin D levels above the mean, and those with low BMD. In contrast, there was an inverse association with the molar ratio for those with BMI ≥30 kg/m(2).

CONCLUSION

We found an overall positive association between circulating levels of IGF1 and IGFBP3 and serum calcium. However, stratification by potential effect-modifiers did not support all suggested hypotheses. Our findings provide more insight into the interplay between calcium and IGF1, which in the future can be investigated in larger observational studies allowing for additional stratifications based on a combination of the different effect-modifiers investigated here.

Topical Treatment with Xiaozheng Zhitong Paste (XZP) Alleviates Bone Destruction and Bone Cancer Pain in a Rat Model of Prostate Cancer-Induced Bone Pain by Modulating the RANKL/RANK/OPG Signaling

To explore the effects and mechanisms of Xiaozheng Zhitong Paste (XZP) on bone cancer pain, Wistar rats were inoculated with vehicle or prostate cancer PC-3 into the tibia bone and treated topically with inert paste, XZP at 15.75, 31.5, or 63 g/kg twice per day for 21 days. Their bone structural damage, nociceptive behaviors, bone osteoclast and osteoblast activity, and the levels of OPG, RANL, RNAK, PTHrP, IGF-1, M-CSF, IL-8, and TNF-α were examined. In comparison with that in the placebo group, significantly reduced numbers of invaded cancer cells, decreased levels of bone damage and mechanical threshold and paw withdrawal latency, lower levels of serum TRACP5b, ICTP, PINP, and BAP, and less levels of bone osteoblast and osteoclast activity were detected in the XZP-treated rats (P<0.05). Moreover, significantly increased levels of bone OPG but significantly decreased levels of RANL, RNAK, PTHrP, IGF-1, M-CSF, IL-8, and TNF-α were detected in the XZP-treated rats (P<0.05 for all). Together, XZP treatment significantly mitigated the cancer-induced bone damage and bone osteoclast and osteoblast activity and alleviated prostate cancer-induced bone pain by modulating the RANKL/RANK/OPG pathway and bone cancer-related inflammation in rats.

Breast cancer and osteoporosis

PURPOSE OF REVIEW

Over the past few years, a number of studies have examined the relationship between breast cancer and osteoporosis, the effect of breast cancer treatment on bone health, and the effect of osteoporosis therapies on aromatase inhibitor-induced bone loss and breast cancer recurrence. New guidelines have been released on the prevention of osteoporotic fractures in women with breast cancer who are on aromatase inhibitors for adjuvant therapy.

RECENT FINDINGS

Despite common factors linking high bone mineral density and increased risk of breast cancer, women with breast cancer are not protected from osteoporosis or osteoporotic fractures. Recent data suggest that aromatase inhibitors have a detrimental effect on bone mineral density and can increase the risk of fractures. Bisphosphonate therapy not only preserves aromatase inhibitor-induced bone loss, but may also improve disease-free survival and decrease risk of death in select women with breast cancer (i.e., postmenopausal women).

SUMMARY

Osteoporosis and breast cancer are common in women, especially in postmenopausal women. Current guidelines suggest that we need to pay special attention to those on aromatase inhibitors to prevent adverse bone outcomes.

Fracture in asian women with breast cancer occurs at younger age

Background

Western breast cancer survivors have an increased risk of osteoporosis and bone fracture. Breast cancer occurs 10 to 20 years earlier in Asian women than in Western women. We investigated if younger Asian women with breast cancer also have increased risk of fracture.

Methods

We used the universal insurance claims data from 2000 to 2003 to identify 22,076 patients with breast cancer and 88,304 women without cancer, frequency matched with age and index date (the date for a health care visit). The incidence of fracture in both cohorts and the hazard ratios (HRs) of fracture in the cancer cohort were estimated by the end of 2009.

Results

The incidence of all types of fracture was higher in the breast cancer cohort than in the comparison cohort (46.72 vs. 42.52 per 10,000 person-years), with adjusted HRs (aHRs) of 1.18 (95% confidence intervals [CI], 1.03–1.35) for hip fractures, 1.12 (95% CI, 0.98–1.28) for forearm fractures and 1.24 (95% CI, 1.04–1.48) for vertebral fractures. The aHRs were significant in both non-traumatic fractures (1.29; 95% CI, 1.11–1.51) and traumatic fractures (1.12; 95% CI, 1.01–1.23). The age-specific aHR was higher for younger breast cancer patients, and was significant for <50 years old patients in both traumatic (aHR 1.35; 95% CI 1.08–1.68) and non-traumatic (aHR, 1.72; 95% CI, 1.21–2.44) fractures.

Conclusion

This study suggests that Asian women with breast cancer might have an increased risk of fracture.

The association between insulin-like growth factor I and bone turnover markers in the general adult population

OBJECTIVES

Growth hormone (GH) and its main mediator, insulin-like growth factor I (IGF-I), play a fundamental role in human metabolism. Previous epidemiological studies investigating the association of IGF-I and bone turnover markers (BTMs) yielded conflicting results and were limited by study design or sample size. Therefore, we aimed to investigate the associations between serum levels of IGF-I or the IGF-I/IGF binging protein 3 (IGFBP-3) ratio and levels of BTMs including procollagen type 1 N-terminal propeptide (PINP), C-terminal telopeptides of type 1 collagen (CTX), and bone-specific alkaline phosphatase (BAP).

METHODS

Data from 1463 men and 1481 women who participated in the first follow-up of the Study of Health in Pomerania were used. IGF-I and IGFBP-3 levels were measured using chemiluminescent immunometric assays on an Immulite 2500 analyzer. BTM levels were measured on the IDS-iSYS Multi-Discipline Automated Analyser. Analyses of variance (ANOVA) and quantile regression models were calculated.

RESULTS

In men <55 years and premenopausal women ANOVA and quantile regression analyses revealed positive associations between IGF-I or even stronger the IGF-I/IGFBP-3 ratio and PINP [per unit increase in IGF-I/IGFBP-3 ratio in men: beta (95%-CI) 2.33 ng/ml (0.91; 3.75), p < 0.01; women: 3.63 ng/ml (2.31; 4.95), p < 0.01] or CTX [men: 20.8 ng/l (3.5; 38.0), p = 0.02; women: 12.0 ng/l (-1.2; 25.2), p = 0.07]. Furthermore in postmenopausal women, IGF-I and the IGF-I/IGFBP-3 ratio were inversely related with CTX levels, whereas an inverse U-shaped relation between IGF-I/IGFBP-3 ratio and PINP was found. Regarding BAP, we observed borderline significant associations with IGF-I or the IGF-I/IGFBP-3 ratio in older subjects only.

CONCLUSION

IGF-I levels and particularly free IGF-I, estimated by the IGF-I/IGFBP-3 ratio, are positively related with PINP as a bone formation marker and CTX as a bone resorption marker in healthy adult men younger than 55 years and premenopausal women. In older subjects the found positive as well as negative relations with BTMs have to be further investigated.

Osteoporosis in young adults: pathophysiology, diagnosis, and management

Postmenopausal osteoporosis is mainly caused by increased bone remodeling resulting from estrogen deficiency. Indications for treatment are based on low areal bone mineral density (aBMD, T-score  ≤ -2.5), typical fragility fractures (spine or hip), and more recently, an elevated 10-year fracture probability (by FRAX®). In contrast, there is no clear definition of osteoporosis nor intervention thresholds in younger individuals. Low aBMD in a young adult may reflect a physiologically low peak bone mass, such as in lean but otherwise healthy persons, whereas fractures commonly occur with high-impact trauma, i.e., without bone fragility. Furthermore, low aBMD associated with vitamin D deficiency may be highly prevalent in some regions of the world. Nevertheless, true osteoporosis in the young can occur, which we define as a T-score below -2.5 at spine or hip in association with a chronic disease known to affect bone metabolism. In the absence of secondary causes, the presence of fragility fractures, such as in vertebrae, may point towards genetic or idiopathic osteoporosis. In turn, treatment of the underlying condition may improve bone mass as well. In rare cases, a bone-specific treatment may be indicated, although evidence is scarce for a true benefit on fracture risk. The International Osteoporosis Foundation (IOF) convened a working group to review pathophysiology, diagnosis, and management of osteoporosis in the young, excluding children and adolescents, and provide a screening strategy including laboratory exams for a systematic approach of this condition.

Cellular and molecular changes in orthodontic tooth movement

Tooth movement induced by orthodontic treatment can cause sequential reactions involving the periodontal tissue and alveolar bone, resulting in the release of numerous substances from the dental tissues and surrounding structures. To better understand the biological processes involved in orthodontic treatment, improve treatment, and reduce adverse side effects, several of these substances have been proposed as biomarkers. Potential biological markers can be collected from different tissue samples, and suitable sampling is important to accurately reflect biological processes. This paper covers the tissue changes that are involved during orthodontic tooth movement such as at compression region (involving osteoblasts), tension region (involving osteoclasts), dental root, and pulp tissues. Besides, the involvement of stem cells and their development towards osteoblasts and osteoclasts during orthodontic treatment have also been explained. Several possible biomarkers representing these biological changes during specific phenomenon, that is, bone remodelling (formation and resorption), inflammation, and root resorption have also been proposed. The knowledge of these biomarkers could be used in accelerating orthodontic treatment.

An old friend in a new light: the role of osteocalcin in energy metabolism

Accumulating evidence suggests interactions between bone and energy metabolism, which may affect the risk of cardiovascular disease. Recent animal studies indicate that osteocalcin (OC) plays a key role in the coordinated regulation of glucose and insulin metabolism while insulin receptors on osteoblasts may regulate bone turnover and circulating OC levels. Association studies, weight loss interventions, and observational data lend some support to the existence and relevance of these mechanisms in humans. However, corroborating evidence from pharmacologic interventions in either bone or glucose metabolism is limited by the number, design, and complex pharmacological effects of the drugs used. Furthermore, such clinical trials are complicated by the alteration of metabolic feedback mechanisms in the insulin resistant state. Purpose-designed studies are needed to further establish the existence and significance of the role of OC and its subfractions in human insulin metabolism. In this review we summarize existing animal evidence regarding the role of OC and its subfractions in bone and energy metabolism and assess current clinical trial evidence relating to the significance and consequences of this relationship in humans.

[Identification and quantification of fat compartments with CT and MRI and their importance]

In addition to being overweight, as defined by the BMI, the distribution, composition and biological activity of adipose tissue are key elements in the cardiovascular risk stratification of patients. Several non-invasive techniques have been developed to quantify local fat depots, whereby computed tomography (CT) and magnetic resonance imaging (MRI) are the most important. In general adipose tissue is subdivided into subcutaneous and visceral compartments and although both are associated with cardiovascular risk factors and disease, visceral fat has on average a stronger association and a clearly higher biological activity independent of traditional risk factors. This maybe explained by the higher endocrine activity and secretion of pro-inflammatory cytokines by visceral fat. Especially pericardial adipose tissue, a local visceral fat depot surrounding the coronary arteries, is associated with the presence, extent and severity of coronary artery disease. However, several other local fat depots have been identified and associations with various diseases have been established. This article gives an overview over the current methods for the identification and quantification of local fat depots and summarizes the hypothesized and known associations. Furthermore, it gives an overview of the potential significance of individual local fat depots for cardiovascular risk stratification.

Effects of diosgenin on myometrial matrix metalloproteinase-2 and -9 activity and expression in ovariectomized rats

Diosgenin, a traditional Yam extraction, has been used in hormone replacement for menopausal women. We aimed to investigate the influences of diosgenin administration upon the MMP-2 and -9 activity and expression and reproductive hormones of ovariectomized (OVX) rats, a model of menopausal status. Seven-week old female Wistar rats with bilateral OVX or sham operation (controls) were divided and administered different dosages of diosgenin (0, 10, 50, or 100 mg/kg/day) for 8 weeks. Serum was then sampled for progesterone (P4) and estradiol (E2) assay and uterine horns harvested. Myometrial MMP-2 and -9 activity and expression were surveyed and myometrial collagen expression was also assayed. The results show higher body weight in OVX rats across the 8 weeks post surgery and no significant differences were noted among OVX or Sham rats with diosgenin supplements. There were lower P4 and E2 concentrations in OVX rats compared to Sham rats, and higher P4 concentration of Sham rats post diosgenin supplement. MMP-2 and -9 mRNA expression and activity was lower in OVX rats, although higher MMP-2 and lower MMP-9 activity/mRNA expression was observed in OVX rats post diosgenin supplementation. Collagen mRNA expression was higher in OVX rats compared to Sham controls, and diosgenin administration decreased collagen mRNA expression in OVX rats. In conclusion, diosgenin is associated with gelatinase expression and collagen metabolism in OVX rats. Diosgenin administration can partially reverse the effects of OVX upon MMP functions and hormone status. Adequate diosgenin supplement might modulate myometrial gelatinase expression and collagen metabolism in menopausal subjects.

Determinants of bone mineral density in obese premenopausal women

Despite being a risk factor for cardiovascular disease and diabetes mellitus, obesity has been thought to protect against osteoporosis. However, recent studies have demonstrated a differential impact of specific fat compartments on bone mineral density (BMD) with visceral adipose tissue (VAT) having potential detrimental effects on BMD. Visceral obesity is also associated with dysregulation of the GH/IGF-1 axis, an important regulator of bone homeostasis. The purpose of our study was to evaluate the differential effects of abdominal fat depots and muscle, vitamin D, and hormonal determinants, including insulin-like growth factor-1 (IGF-1), testosterone, and estradiol, on trabecular BMD of the lumbar spine. We studied 68 healthy obese premenopausal women (mean BMI, 36.7±4.2 kg/m(2)). Quantitative computed tomography (QCT) was used to assess body composition and lumbar trabecular BMD. There was an inverse association between BMD and VAT, independent of age and BMI (p=0.003). IGF-1 correlated positively with BMD and negatively with VAT and, in stepwise multivariate regression modeling, was the strongest predictor of BMD and procollagen type 1 amino-terminal propeptide (P1NP). Thigh muscle cross sectional area (CSA) and thigh muscle density were also associated with BMD (p<0.05), but 25-hydroxyvitamin D [25(OH)D], testosterone, free testosterone, and estradiol levels were not. 25(OH)D was associated inversely with BMI, total, and subcutaneous abdominal adipose tissue (p<0.05). These findings support the hypothesis that VAT exerts detrimental effects, whereas muscle mass exerts positive effects on BMD in premenopausal obese women. Moreover, our findings suggest that IGF-1 may be a mediator of the deleterious effects of VAT on bone health through effects on bone formation.

Vitamin D, disease and therapeutic opportunities

The discovery of the vitamin D endocrine system and a receptor for the hormonal form, 1α,25-dihydroxyvitamin D(3), has brought a new understanding of the relationship between vitamin D and metabolic bone diseases, and has also established the functions of vitamin D beyond the skeleton. This has ushered in many investigations into the possible roles of vitamin D in autoimmune diseases, cardiovascular disorders, infectious diseases, cancers and granuloma-forming diseases. This article presents an evaluation of the possible roles of vitamin D in these diseases. The potential of vitamin D-based therapies in treating diseases for which the evidence is most compelling is also discussed.

Influence of gene variants related to calcium homeostasis on biochemical parameters of women with polycystic ovary syndrome

PURPOSE

The purpose of this study was to evaluate the associations between polymorphisms in vitamin D receptor (VDR), parathyroid hormone (PTH), calcium sensing receptor (CASR), insulin receptor (INSR), and adiponectin (ADIPOQ) genes and biochemical characteristics of women with polycystic ovary syndrome (PCOS).

METHODS

Serum levels of LH, FSH, estradiol, testosterone, prolactin, SHBG, glucose, IGF-1, IGFBP-1, calcium, phosphorus, PTH, 25(OH)D, and 1,25(OH)(2) D were measured in 56 women with PCOS. Furthermore, genotyping five, one, one, two, and two polymorphisms of the VDR, PTH, CASR, INSR, and ADIPOQ genes, respectively, were performed.

RESULTS

The VDR TaqI "CC" genotype was associated with elevated serum levels of LH (p = 0.011). There were significant associations between decreased levels of SHBG and both VDR BsmI "GG" (p = 0.009) and ADIPOQ BsmI "CC" (p = 0.016) genotypes. Furthermore, patients with CaSR Hin1I "TG" genotype showed higher HoMA-IR (p = 0.008). All these associations remained significant after Bonferroni correction. In addition, phosphorus correlated negatively with estradiol (r =  -0.298, P = 0.026) and positively with glucose (r = 0.287, P = 0.032).

CONCLUSIONS

These data indicated for the first time that it is possible that the VDR and CASR gene variants through their effects on LH and SHBG levels, and insulin resistance are involved in pathogenesis of PCOS.

Investigational anabolic therapies for osteoporosis

IMPORTANCE OF THE FIELD

Anabolic therapy, or stimulating the function of bone-forming osteoblasts, is the preferred pharmacological intervention for osteoporosis.

AREAS COVERED IN THIS REVIEW

We reviewed bone anabolic agents currently under active investigation. The bone anabolic potential of IGF-I and parathyroid hormone-related protein is discussed in the light of animal data and human studies. We also discuss the use of antagonists of the calcium-sensing receptor (calcilytics) as orally administered small molecules capable of transiently elevating serum parathyroid hormone (PTH). Further, we reviewed novel anabolic agents targeting members of the wingless tail (Wnt) signaling family that regulate bone formation including DKK-1, sclerostin, Thp1, and glycogen synthase kinase 3beta. We have also followed up on the promise shown by beta-blockers in modulating the activity of sympathetic nervous system, thus affecting bone anabolism. We give critical consideration to neutralizing the activity of activin A, a negative regulator of bone mass by soluble activin receptor IIA, as a strategy to promote bone formation.

WHAT THE READER WILL GAIN

Update on various strategies to promote osteoblast function currently under evaluation.

TAKE HOME MESSAGE

In spite of favorable results in experimental models, none of these strategies has yet achieved the ultimate goal of providing an alternative to injectable PTH, the sole anabolic therapy in clinical use.

Reference intervals of biochemical bone turnover markers for Saudi Arabian women: a cross-sectional study

Biochemical bone turnover markers (BTMs) provide important information on the diagnosis, therapy and monitoring of metabolic bone diseases including osteoporosis. One goal of antiresorptive therapy in women is to decrease biochemical BTMs to the lower half of reference intervals for healthy pre-menopausal counterparts, using newly developed automated assays of such markers. The main objectives of the present study were to: (1) establish reference interval values for the following biochemical BTMs: serum osteocalcine (s-OC), bone alkaline phosphatase (s-bone ALP), procollagen type 1 N-terminal propeptide (s-PINP), crosslinked C-terminal telopeptide of Type 1 collagen (s-CTX), tartarate-resistant acid phosphatase isoform 5b (s-TRACP-5b) and urinary: CTX (u-CTX), N-telopeptides of type 1 collagen (u-NTX), pyridinoline (u-PYD) and deoxypyridinoline (u-DPD) in randomly selected Saudi healthy pre-menopausal women; (2) study the changes in biochemical BTMs in relation to age in pre- and post-menopausal women and the factors reported to influence bone turnover and (3) determine the effect of menopausal status on BTMs. A total of 2125 women were studied [including (n=1557) pre-, and (n=568) post-menopausal women, respectively, aged 20-79 years]. A total of 765 healthy pre-menopausal women (aged 35-45 years) were used to establish reference intervals for biochemical BTMs. All women studied were medically examined and had their bone mineral density (BMD) values obtained for the lumbar spine (L(1)-L(4)) and femoral neck according to detailed inclusion criteria. In all women, values of biochemical BTMs, decreased with increasing age up to the age of 45 years, increased steeply among women in their 50s and remained increased in post-menopausal women. Significant increases were evident in all biochemical BTMs in post-menopausal women with >5 years since menopause with the exception of s-OC, u-DPD, and u-PYD. Using stepwise multiple linear regression analysis, several variables were identified (depending on the BTM) as determinants of BTMs including age, BMI, parity, FSH, LH, PTH, s-Ca, s-Mg, s-PO(4) and 25(OH)D. In the reference intervals group, there are no significant correlations between any of the biochemical BTMs and age of menarche, day of menstrual cycle, physical activity, total daily dietary calcium and caffeine intakes and parity. It is recommended that the age range 35-45 years should be used when establishing biochemical BTMs reference intervals in Saudi Arabian pre-menopausal women.