Follicle-Stimulating Hormone Increases the Risk of Postmenopausal Osteoporosis by Stimulating Osteoclast Differentiation

Neuroendocrinology of bone

The past decade has witnessed significant advances in our understanding of skeletal homeostasis and the mechanisms that mediate the loss of bone in primary and secondary osteoporosis. Recent breakthroughs have primarily emerged from identifying disease-causing mutations and phenocopying human bone disease in rodents. Notably, using genetically-modified rodent models, disrupting the reciprocal relationship with tropic pituitary hormone and effector hormones, we have learned that pituitary hormones have independent roles in skeletal physiology, beyond their effects exerted through target endocrine glands. The rise of follicle-stimulating hormone (FSH) in the late perimenopause may account, at least in part, for the rapid bone loss when estrogen is normal, while low thyroid-stimulating hormone (TSH) levels may contribute to the bone loss in thyrotoxicosis. Admittedly speculative, suppressed levels of adrenocorticotropic hormone (ACTH) may directly exacerbate bone loss in the setting of glucocorticoid-induced osteoporosis. Furthermore, beyond their established roles in reproduction and lactation, oxytocin and prolactin may affect intergenerational calcium transfer and therefore fetal skeletal mineralization, whereas elevated vasopressin levels in chronic hyponatremic states may increase the risk of bone loss.. Here, we discuss the interaction of each pituitary hormone in relation to its role in bone physiology and pathophysiology.

Bone mineral density, turnover, and microarchitecture assessed by second-generation high-resolution peripheral quantitative computed tomography in patients with Sheehan's syndrome

Sheehan's syndrome (SS) is a rare but well-characterized cause of hypopituitarism. Data on skeletal health is limited and on microarchitecture is lacking in SS patients.

PURPOSE

We aimed to explore skeletal health in SS with bone mineral density (BMD), turnover, and microarchitecture.

METHODS

Thirty-five patients with SS on stable replacement therapy for respective hormone deficiencies and 35 age- and BMI-matched controls were recruited. Hormonal profile and bone turnover markers (BTMs) were measured using electrochemiluminescence assay. Areal BMD and trabecular bone score were evaluated using DXA. Bone microarchitecture was assessed using a second-generation high-resolution peripheral quantitative computed tomography.

RESULTS

The mean age of the patients was 45.5 ± 9.3 years with a lag of 8.3 ± 7.2 years prior to diagnosis. Patients were on glucocorticoid (94%), levothyroxine (94%), and estrogen-progestin replacement (58%). None had received prior growth hormone (GH) replacement. BTMs (P1NP and CTX) were not significantly different between patients and controls. Osteoporosis (26% vs. 16%, p = 0.01) and osteopenia (52% vs. 39%, p = 0.007) at the lumbar spine and femoral neck (osteoporosis, 23% vs. 10%, p = 0.001; osteopenia, 58% vs. 29%, p = 0.001) were present in greater proportion in SS patients than matched controls. Bone microarchitecture analysis revealed significantly lower cortical volumetric BMD (vBMD) (p = 0.02) at the tibia, with relative preservation of the other parameters.

CONCLUSION

Low areal BMD (aBMD) is highly prevalent in SS as compared to age- and BMI-matched controls. However, there were no significant differences in bone microarchitectural measurements, except for tibial cortical vBMD, which was lower in adequately treated SS patients.

Antiosteoporosis effect of bryodulcosigenin on ovariectomy-induced osteoporosis in experimental rats

PURPOSE

Osteoporosis is a bone disease which commonly occurred in postmenopausal women. Almost 10 percent of world population and approximately 30% of women (postmenopausal) suffer from this disease. Alternative medicine has great success in the treatment of osteoporosis disease. Bryodulcosigenin, a potent phytoconstituent, already displayed the anti-inflammatory and antioxidant effect. In this study, we made effort to analyze the antiosteoporosis effect of bryodulcosigenin against ovariectomy (OVX) induced osteoporosis in rats.

METHODS

Swiss albino Wistar rats were grouped into fIve groups and given an oral dose of bryodulcosigenin (10, 20 and 30 mg/kg) for eight weeks. Body weight, uterus, bone mineral density, cytokines, hormones parameters, transforming growth factor (TGF)-β, insulin-like growth factor (IGF), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), and its ratio were estimated.

RESULTS

Bryodulcosigenin significantly (p < 0.001) suppressed the body weight and enhanced the uterine weight and significantly (p < 0.001) increased the bone mineral density in whole femur, caput femoris, distal femur and proximal femur. Bryodulcosigenin significantly (P < 0.001) altered the level of biochemical parameters at dose dependent manner, significantly (P < 0.001) improved the level of estrogen and suppressed the level of follicle stimulating hormone and luteinizing hormone. Bryodulcosigenin significantly (P < 0.001) improved the level of OPG and suppressed the level of RANKL.

CONCLUSIONS

Bryodulcosigenin reduced the cytokines level and suppressed the TGF-β and IGF. We concluded that bryodulcosigenin is an antiosteoporosis medication based on the findings.

Pituitary crosstalk with bone, adipose tissue and brain

Traditional textbook physiology has ascribed unitary functions to hormones from the anterior and posterior pituitary gland, mainly in the regulation of effector hormone secretion from endocrine organs. However, the evolutionary biology of pituitary hormones and their receptors provides evidence for a broad range of functions in vertebrate physiology. Over the past decade, we and others have discovered that thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone, prolactin, oxytocin and arginine vasopressin act directly on somatic organs, including bone, adipose tissue and liver. New evidence also indicates that pituitary hormone receptors are expressed in brain regions, nuclei and subnuclei. These studies have prompted us to attribute the pathophysiology of certain human diseases, including osteoporosis, obesity and neurodegeneration, at least in part, to changes in pituitary hormone levels. This new information has identified actionable therapeutic targets for drug discovery.

Association of follicle-stimulating hormone with bone turnover markers and bone mineral density in Chinese women across the menopausal transition

BACKGROUND

Elevated follicle-stimulating hormone (FSH) is associated with an increased risk of postmenopausal osteoporosis. This study investigated the association of serum FSH with bone turnover markers (BTMs) and bone mineral density (BMD) in healthy women undergoing menopausal transition.

METHODS

A total of 487 healthy women (age 35-65 years, 50 ± 8.5 years) were enrolled in this study. Serum FSH, BTMs, and BMD at lumbar spine and total hip were measured in these subjects.

RESULTS

Follicle-stimulating hormone was positively correlated with various BTMs (r = 0.339-0.583, all p < 0.001) and negatively correlated with lumbar spine and total hip BMD (r = -0.629 and -0.514, all p < 0.001). After adjusting for age and body mass index, the partial correlation coefficients of FSH with BTMs and BMD remained significant. Estimating from the regression equation, for every 10 IU/L increase in serum FSH, BTMs increased by 0.38-3.6 units, and BMD decreased by 0.03-0.05 g/cm2 , respectively. Multiple linear regression analysis showed that FSH was a positive factor for serum bone-specific alkaline phosphatase, osteocalcin, and N-telopeptide of collagen type 1 (β = 0.188-0.403, all p < 0.001), and a negative factor for lumbar spine BMD and serum C-telopeptide of collagen type 1 (β = -0.629 and -0.183, all p < 0.001).

CONCLUSIONS

This study suggests that serum FSH levels are an independent risk factor for BTMs and BMD in menopause-transitioning women, particularly for serum BAP and lumbar spine BMD.

Bones and Hormones: Interaction between Hormones of the Hypothalamus, Pituitary, Adipose Tissue and Bone

The bony skeleton, as a structural foundation for the human body, is essential in providing mechanical function and movement. The human skeleton is a highly specialized and dynamic organ that undergoes continuous remodeling as it adapts to the demands of its environment. Advances in research over the last decade have shone light on the various hormones that influence this process, modulating the metabolism and structural integrity of bone. More recently, novel and non-traditional functions of hypothalamic, pituitary, and adipose hormones and their effects on bone homeostasis have been proposed. This review highlights recent work on physiological bone remodeling and discusses our knowledge, as it currently stands, on the systemic interplay of factors regulating this interaction. In this review, we provide a summary of the literature on the relationship between bone physiology and hormones including kisspeptin, neuropeptide Y, follicle-stimulating hormone (FSH), prolactin (PRL), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), leptin, and adiponectin. The discovery and understanding of this new functionality unveils an entirely new layer of physiologic circuitry.

The non-linear associations of serum follicle-stimulating hormone levels with bone mineral density and the risk of osteoporosis during menopausal transition: an analysis of National Health and Nutrition Examination Survey data

PURPOSE

To explore the non-linear associations of serum FSH levels with BMD and the risk of osteoporosis in pre- and postmenopausal women.

METHODS

Data analyzed in this study were derived from the National Health and Nutrition Examination Survey (NHANES) III and the NHANES from 1999 to 2002. Women aged from 35 to 60 years with complete data of serum FSH levels and BMD were eligible. Serum FSH levels were assayed using the Microparticle Enzyme Immunoassay technology. Lumbar spine and femur neck BMD were measured using a dual energy X-ray absorptiometry. Osteoporosis was assessed according to BMD of lumbar spine, total femur, and femur neck.

RESULTS

This study included 3743 women. A significant non-linear association of serum FSH levels with lumbar spine BMD was observed only in postmenopausal women (P for non-linear association = 0.013) but not in premenopausal women (P for non-linear association = 0.092). The results of femur neck BMD were comparable with those of lumbar spine BMD. Meanwhile, there was significant non-linear association of serum FSH levels with the risk of osteoporosis only in postmenopausal women (P for non-linear association = 0.050).

CONCLUSION

Non-linear associations of serum FSH levels with BMD at lumbar spine and femur neck were observed only in postmenopausal women. Meanwhile, serum FSH levels were non-linearly associated with the risk of osteoporosis in postmenopausal women.

Follicle-stimulating hormone is associated with low bone mass in postmenopausal women

We evaluated the influence of two endogenous hormones on bone health in older women. Higher FSH was associated with bone disease, especially in lower estradiol environments. FSH attenuated the relationship between estradiol and bone. This may provide a mechanism through which future clinical research intervenes on bone loss.

INTRODUCTION/PURPOSE

Despite preclinical evidence for an inverse association of follicle-stimulating hormone (FSH) and bone mineral density (BMD), no large epidemiologic studies have evaluated the separate and joint influences of FSH and estradiol on bone in postmenopausal women.

METHODS

In a cross-sectional study of 675 postmenopausal women, we evaluated associations of serum FSH and dual X-ray absorptiometry (DXA)-classified areal BMD as well as low bone mass or osteoporosis (T-score <  - 1.0) of the femoral neck and total hip. We stratified this analysis by serum estradiol (cut at the median). We tested whether FSH mediates the association of estradiol and BMD using the Sobel test.

RESULTS

In linear regression models, there was a significant inverse association of serum FSH with both femoral neck and total hip BMD (both p < 0.01) when adjusted for age, hormone therapy (HT) use, and diabetes. In fully adjusted logistic regression models, women in the highest FSH tertile had higher odds of low bone mass/osteoporosis at the femoral neck (OR = 2.98; 95% CI = 1.86-4.77) and at the total hip (OR = 1.74; 95% CI = 1.06-2.84) compared to those in the lowest FSH tertile. We report evidence of effect modification by estradiol in stratified models and an interaction term. FSH met all criteria of a mediator, including an estimated 70% attenuation of the estradiol-BMD relationship (Sobel p value < 0.001).

CONCLUSIONS

FSH is associated with higher odds of having low bone mass/osteoporosis even after accounting for HT use. FSH is a mediator of the relationship between estradiol and BMD in healthy postmenopausal women. Larger, prospective studies of FSH concentrations and bone health are needed.

Non-reproductive effects of follicle-stimulating hormone in young men

OBJECTIVE

Follicle-stimulating hormone (FSH) receptor expression has been reported in many extra-gonadal tissues, raising the question of non-reproductive effects of FSH. Because of increasing usage of FSH in treatment of male infertility, deeper knowledge of possible harmful off-target effects of FSH is warranted.

METHODS

In total, 33 healthy young men (mean age 30 years) were included in the study. All received an s.c. injection of gonadotropin-releasing hormone (GnRH) antagonist and n = 16 were randomized to 300 IU recombinant FSH (300 IE 3 times/week) for 5 weeks at first visit (V1) whereas n = 17 served as controls. Blood samples were taken at (V1), after 3 weeks (V2), and after 5 weeks (V3), when the study ended. At V2, all subjects received 1000 mg testosterone undecanoate i.m. A standard set of bio- and inflammatory markers were compared between the groups using the Mann-Whitney test adjusted for multiple testing.

RESULTS

As compared to controls, the FSH treated men had higher SHBG and albumin concentrations at V2 (p = 0.024 and 0.027, respectively), and lower levels of alanine aminotransferase (p = 0.026) and magnesium (p = 0.028) at V3. However, none of the results remained statistically significant after Bonferroni correction (p > 0.0011).

CONCLUSIONS

FSH had no significant effects on non-reproductive organs when given in standard therapeutic doses to young men for 5 weeks. Therefore, the FSH treatment can be considered safe in otherwise healthy young men, constituting candidates for the infertility treatment with FSH.

Reduction of Osteoclastic Differentiation of Raw 264.7 Cells by EMF Exposure through TRPV4 and p-CREB Pathway

In this study, we investigated the effect of EMF exposure on the regulation of RANKL-induced osteoclast differentiation in Raw 264.7 cells. In the EMF-exposed group, the cell volume did not increase despite RANKL treatment, and the expression levels of Caspase-3 remained much lower than those in the RANKL-treated group. TRAP and F-actin staining revealed smaller actin rings in cells exposed to EMF during RANKL-induced differentiation, indicating that EMF inhibited osteoclast differentiation. EMF-irradiated cells exhibited reduced mRNA levels of osteoclastic differentiation markers cathepsin K (CTSK), tartrate-resistant acid phosphatase (TRAP), and matrix metalloproteinase 9 (MMP-9). Furthermore, as measured by RT-qPCR and Western blot, EMF induced no changes in the levels of p-ERK and p-38; however, it reduced the levels of TRPV4 and p-CREB. Overall, our findings indicate that EMF irradiation inhibits osteoclast differentiation through the TRPV4 and p-CREB pathway.

Alzheimer's Disease and Impaired Bone Microarchitecture, Regeneration and Potential Genetic Links

Alzheimer's Disease (AD) and osteoporosis are both age-related degenerative diseases. Many studies indicate that these two diseases share common pathogenesis mechanisms. In this review, the osteoporotic phenotype of AD mouse models was discussed, and shared mechanisms such as hormonal imbalance, genetic factors, similar signaling pathways and impaired neurotransmitters were identified. Moreover, the review provides recent data associated with these two diseases. Furthermore, potential therapeutic approaches targeting both diseases were discussed. Thus, we proposed that preventing bone loss should be one of the most important treatment goals in patients with AD; treatment targeting brain disorders is also beneficial for osteoporosis.

Bone circuitry and interorgan skeletal crosstalk

The past decade has seen significant advances in our understanding of skeletal homeostasis and the mechanisms that mediate the loss of bone integrity in disease. Recent breakthroughs have arisen mainly from identifying disease-causing mutations and modeling human bone disease in rodents, in essence, highlighting the integrative nature of skeletal physiology. It has become increasingly clear that bone cells, osteoblasts, osteoclasts, and osteocytes, communicate and regulate the fate of each other through RANK/RANKL/OPG, liver X receptors (LXRs), EphirinB2-EphB4 signaling, sphingolipids, and other membrane-associated proteins, such as semaphorins. Mounting evidence also showed that critical developmental pathways, namely, bone morphogenetic protein (BMP), NOTCH, and WNT, interact each other and play an important role in postnatal bone remodeling. The skeleton communicates not only with closely situated organs, such as bone marrow, muscle, and fat, but also with remote vital organs, such as the kidney, liver, and brain. The metabolic effect of bone-derived osteocalcin highlights a possible role of skeleton in energy homeostasis. Furthermore, studies using genetically modified rodent models disrupting the reciprocal relationship with tropic pituitary hormone and effector hormone have unraveled an independent role of pituitary hormone in skeletal remodeling beyond the role of regulating target endocrine glands. The cytokine-mediated skeletal actions and the evidence of local production of certain pituitary hormones by bone marrow-derived cells displays a unique endocrine-immune-skeletal connection. Here, we discuss recently elucidated mechanisms controlling the remodeling of bone, communication of bone cells with cells of other lineages, crosstalk between bone and vital organs, as well as opportunities for treating diseases of the skeleton.

Independent Skeletal Actions of Pituitary Hormones

Over the past years, pituitary hormones and their receptors have been shown to have non-traditional actions that allow them to bypass the hypothalamus-pituitary-effector glands axis. Bone cells-osteoblasts and osteoclasts-express receptors for growth hormone, follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin, and vasopressin. Independent skeletal actions of pituitary hormones on bone have been studied using genetically modified mice with haploinsufficiency and by activating or inactivating the receptors pharmacologically, without altering systemic effector hormone levels. On another front, the discovery of a TSH variant (TSH-βv) in immune cells in the bone marrow and skeletal action of FSHβ through tumor necrosis factor α provides new insights underscoring the integrated physiology of bone-immune-endocrine axis. Here we discuss the interaction of each pituitary hormone with bone and the potential it holds in understanding bone physiology and as a therapeutic target.

Roles of Follicle-Stimulating Hormone on Bone Metabolism in Late Postmenopausal Women

BACKGROUND

The effects of elevated follicle-stimulating hormone (FSH) levels on physiological changes in the bone remain unclear. This study aimed to clarify the association between FSH concentrations and bone mineral density (BMD) and bone turnover markers (BTM) in late postmenopausal women.

METHODS

A total of 169 Korean women were enrolled. The participants' ages ranged from 60 to 84 years (mean age, 69.0±5.1) and reported a mean duration of 19.4±6.6 years since menopause (YSM). The participants showed an average body mass index (BMI) of 24.4±2.8 kg/m2. Age, YSM, estradiol, testosterone, and BMI were confounders in the Pearson's partial correlation. A test for trends across the quartiles of FSH levels was performed for each variable.

RESULTS

The mean FSH and estradiol concentrations were 61.5 IU/L and 2.9 pg/mL, respectively. Serum FSH concentration was not significantly associated with BMD (lumbar, r=0.09, P=0.30; total hip, r=0.00, P=0.96; and femoral neck, r=0.05, P=0.62). BTM across the FSH quartiles did not show any trend association (bone-specific alkaline phosphate, P=0.31; crosslinked C-terminal telopeptide of type I collagen, P=0.90). Instead, FSH levels were negatively correlated with BMI (r=-0.34, P=0.00). In the multivariate regression model adjusted for age, testosterone, and estradiol, only BMI showed a negative value across the FSH quartiles (β coefficient -0.11, P=0.00).

CONCLUSIONS

This study identified that high FSH concentrations were not associated with bone loss or high bone turnover in women in the late postmenopausal period.

Micro-computed tomography assessment of bone structure in aging mice

High-resolution computed tomography (CT) is widely used to assess bone structure under physiological and pathological conditions. Although the analytic protocols and parameters for micro-CT (μCT) analyses in mice are standardized for long bones, vertebrae, and the palms in aging mice, they have not yet been established for craniofacial bones. In this study, we conducted a morphometric assessment of craniofacial bones, in comparison with long bones, in aging mice. Although age-related changes were observed in the microarchitecture of the femur, tibia, vertebra, and basisphenoid bone, and were more pronounced in females than in males, the microarchitecture of both the interparietal bone and body of the mandible, which develop by intramembranous ossification, was less affected by age and sex. By contrast, the condyle of the mandible was more affected by aging in males compared to females. Taken together, our results indicate that mouse craniofacial bones are uniquely affected by age and sex.

Sexual dimorphism in the relation between sex hormones and osteoporosis in patients with type 2 diabetes mellitus

INTRODUCTION

To investigate the association between sex hormones and osteoporosis in type 2 diabetic mellitus (T2DM) patients.

MATERIALS AND METHODS

We performed a retrospective study in patients with T2DM. The patients were assigned into three groups (normal bone mineral density, osteopenia, and osteoporosis) in both sexes. The clinical characteristics, bone metabolic markers, and sex hormones were compared. The relationship between the sex hormones and osteoporosis was analyzed by ordinary regression analysis. Statistical analysis was performed using SPSS 26.0.

RESULTS

A total of 795 T2DM patients (446 men ≥ 50 years old and 349 postmenopausal women) were identified and analyzed. The osteoporosis group had the lowest estradiol level in men (P = 0.013) and the highest follicle-stimulating hormone (FSH) level in women (P = 0.042). In the multivariate analysis, men with lower estradiol levels (< 87.96 pmol/L) had a nearly 1.6-fold increased risk for osteoporosis than those with the higher estradiol levels (> 122.82 pmol/L). In addition, women with lower FSH (< 41.17 IU/L) had nearly 0.6-fold for osteoporosis compared to those with higher FSH (> 60.83 IU/L) after adjusting for age, duration of T2DM, body mass index, pulse pressure, creatinine clearance, glycosylated hemoglobin, fasting C-peptide, and estradiol (in FSH) or FSH (in estradiol).

CONCLUSION

In T2DM, the estrogen level was negatively correlated with osteoporosis in men, and the FSH level was positively correlated with the osteoporosis in women.

Follicle-stimulating hormone and blood lead levels with bone mineral density and the risk of fractures in pre- and postmenopausal women

BACKGROUND

The conclusions on the associations of serum follicle-stimulating hormone (FSH) and blood lead levels with bone mineral density (BMD) were controversial. Furthermore, little was known on the impacts of co-existence of serum FSH and blood lead levels on BMD and the risk of fractures in premenopausal and postmenopausal women. Therefore, the present study aimed to examine the associations of serum FSH and blood lead levels with BMD and the risk of fractures in premenopausal and postmenopausal women.

METHODS

Data were derived from the National Health and Nutrition Examination Survey. FSH is assayed using the Microparticle Enzyme Immunoassay technology. Blood lead levels were measured using atomic absorption spectrometry. BMD was measured using dual energy X-ray absorptiometry. Fractures were defined as subjects with fractures in any site of hip, wrist, and spine.

RESULTS

This study included 3798 participants. Elevated blood lead levels were associated with increased serum FSH levels (β= 48.22, 95% CI: 40.21~ 56.22). Serum FSH levels were negatively associated with total femur BMD in pre- and postmenopausal women. However, elevated serum FSH levels were associated with a lower lumbar spine BMD and a higher risk of fractures only in postmenopausal women (β= -0.0010, 95% CI: -0.0015~ -0.0006; OR: 1.007, 95% CI: 1.000~1.014, respectively).

CONCLUSIONS

Serum lead levels were associated with serum FSH levels. Serum FSH levels were associated with a lower BMD and a higher risk of fractures.

The prevalence of vertebral fractures among Indian perimenopausal women and its association with ovarian biomarkers

INTRODUCTION

There is dearth of data on prevalent vertebral fractures in perimenopausal women in India and limited literature on the utility of FSH, AMH and estradiol in evaluating bone health them. The objective was to study the prevalence of vertebral fractures (VF) and to assess the utility of FSH, estradiol and AMH in predicting them in Indian perimenopausal women MATERIALS AND METHODS: It was a cross-sectional study. Perimenopausal women aged 40-49 years underwent assessment for prevalent vertebral fractures, bone mineral density (BMD) and trabecular bone score (TBS). Utility of serum FSH, estradiol and AMH in predicting prevalent vertebral fractures was also assessed.

RESULTS

A total of 300 perimenopausal women with mean (SD) age of 43.2 (2.8) years was recruited and 18% had moderate-severe VF. Mean (SD) serum AMH was lower in perimenopausal women with VF as compared to those without fractures [0.752 (0.594) vs 1.023 (0.704) P = 0.006]. AMH showed significant positive correlation with TBS (r = 0.3; P < 0.001) and BMD at the femoral neck (r = 0.2; P < 0.001) and lumbar spine (r = 0.3; P < 0.001).On ROC analysis, AMH demonstrated good performance in predicting prevalent VF with an AUC of 0.800 (95% CI 0.705-0.880) and a sensitivity of 85% and specificity of 60% at a cut-off of 1.12 ng/mL. On an exploratory multivariate logistic regression analysis, AMH significantly predicted prevalent fractures with an adjusted OR (OR) of 1.85 (95% CI: 1.03-3.00; P = 0.04). The performance of FSH and estradiol in predicting prevalent fractures was sub-optimal.

CONCLUSION

About one-fifth of the study subjects had prevalent vertebral fractures. AMH may be a menstrual cycle independent biomarker and may reflect bone loss in perimenopausal women. Further prospective studies are needed to validate these findings.

Bone mineralization and immediate function of six dental implants in patients with Klinefelter syndrome

Patients with Klinefelter syndrome face many challenges in oral treatment and bone mineralization due to multiple systemic dysfunctions. This case report follows the geometrical treatment with immediate implant loading of an adult male patient with Klinefelter syndrome. Satisfactory results were demonstrated in clinical follow-up.

FSH Level and Changes in Bone Mass and Body Composition in Older Women and Men

CONTEXT

FSH may have independent actions on bone remodeling and body fat regulation. Cross-sectionally, we have shown that serum FSH is associated with bone mineral density (BMD) and body fat in older postmenopausal women, but it remains unknown whether FSH predicts bone and fat changes.

OBJECTIVE

We examined whether baseline FSH level is associated with subsequent bone loss or body composition changes in older adults.

SETTING, DESIGN, PARTICIPANTS

We studied 162 women and 158 men (mean age 82 ± 4 years) from the Age, Gene/Environment Susceptibility (AGES)-Bone Marrow Adiposity cohort, a substudy of the AGES-Reykjavik Study of community-dwelling older adults. Skeletal health and body composition were characterized at baseline and 3 years later.

MAIN OUTCOMES

Annualized change in BMD and body composition by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). Models were adjusted for serum estradiol and testosterone levels.

RESULTS

There was no evidence for an association between baseline FSH level and change in BMD or body composition by DXA or QCT. For femoral neck areal BMD, adjusted mean difference (95% CI) per SD increase in FSH was 1.3 (-0.7 to 3.3) mg/cm2/y in women, and -0.2 (-2.6 to 2.2) mg/cm2/y in men. For visceral fat, adjusted mean difference (95% CI) per SD increase in FSH was 1.80 (-0.03 to 3.62) cm2/y in women, and -0.33 (-3.73 to 3.06) cm2/y in men.

CONCLUSIONS

Although cross-sectional studies and studies in perimenopausal women have demonstrated associations between FSH and BMD and body composition, in older adults, FSH level is not associated with bone mass or body composition changes.

The impact of leuprolide acetate-loaded calcium phosphate silicate cement to bone regeneration under osteoporotic conditions

Osteoporosis is detrimental to the health of skeletal structure and significantly increases the risks of bone fracture. Moreover, bone regeneration is adversely impaired by increased osteoclastic activities as a result of osteoporosis. In this study, we developed a novel formulation of injectable bone cement based on calcium phosphate silicate cement (CPSC) and leuprolide acetate (LA). Several combinations of LA-CPSC bone cement were characterized and, it is found that LA could increase the setting time and compressive strength of CPSC in a concentration-dependent manner. Moreover, thein vitroresults revealed that LA-CPSC was biocompatible and able to encourage the osteoblast proliferation via the mTOR signalling pathway. Furthermore, the LA-CPSC was implanted in the osteoporotic rats to evaluate its effectiveness to repair bone fractures under the osteoporotic conditions. The biomarker study and micro-CT analyses indicated that LA-CPSC could effectively reduce the osteoclast activities and promote the bone regeneration. In conclusion, our study demonstrated that LA-CPSC injectable bone cement should be a viable solution to repair bone fractures under the osteoporotic conditions.

Effects of Soy Isoflavones on Biochemical Markers of Bone Metabolism in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This systematic review and meta-analysis of randomized controlled trials was performed to more completely assess potential changes in bone turnover marker levels in postmenopausal women during the intake of soy isoflavones. PubMed (Medline) and EMBASE were searched for relevant studies, and their quality was evaluated according to Cochrane criteria. The levels of markers were evaluated in a total of 1114 women who ingested mean daily doses of 98.2 mg (30.9 to 300) of soy isoflavones for 3 to 24 months, in comparison to those of 1081 subjects who used a placebo. Ten, eighteen, eight, and fourteen comparison studies were finally selected for an estimation of the effects on osteocalcin (OC), bone alkaline phosphatase (BAP), pyridinoline (PYD), and deoxypyridinoline (DPD), respectively. A summary of the results of intervention was as follows: 4.16%, 95% CI: -7.72-16.04, p = 0.49 for OC; 5.50%, 95% CI: -3.81-14.82, p = 0.25 for BAP; -12.09%, 95% CI: -25.37-1.20, p = 0.07 for PYD; and -7.48%, 95% CI: -15.37-0.41, p = 0.06 for DPD. The meta-analysis of the included studies revealed some statistically insignificant observations that soy isoflavones intake is associated with a trend in increased levels of OC and BAP, as well as a trend in reduced levels of PYD and DPD. Soy isoflavones may have a beneficial effect on bone formation markers, but this requires extensive multi-center research.

Recent advances in understanding gonadotropin signaling

Gonadotropins are glycoprotein sex hormones regulating development and reproduction and bind to specific G protein–coupled receptors expressed in the gonads. Their effects on multiple signaling cascades and intracellular events have recently been characterized using novel technological and scientific tools. The impact of allosteric modulators on gonadotropin signaling, the role of sugars linked to the hormone backbone, the detection of endosomal compartments supporting signaling modules, and the dissection of different effects mediated by these molecules are areas that have advanced significantly in the last decade. The classic view providing the exclusive activation of the cAMP/protein kinase A (PKA) and the steroidogenic pathway by these hormones has been expanded with the addition of novel signaling cascades as determined by high-resolution imaging techniques. These new findings provided new potential therapeutic applications. Despite these improvements, unanswered issues of gonadotropin physiology, such as the intrinsic pro-apoptotic potential to these hormones, the existence of receptors assembled as heteromers, and their expression in extragonadal tissues, remain to be studied. Elucidating these issues is a challenge for future research.

Do We Use Methylation of NFATC1 and FOS Genes As a Biomarker for Postmenopausal Osteoporosis?

Genetic and epigenetic factors have an important role during the development of osteoporosis. Receptor activator of nuclear factor-κ B (NF-κB) (RANK)/receptor activator of NF-κB ligand (RANKL) pathway is important for the bone remodeling, and NFATC1 and FOS are the downtargets of this pathway. Here, we report methylation status of NFATC1 and FOS genes in post- and premenopausal women. In this study, 30 premenopausal and 35 postmenopausal women were included. Methylation sensitive-high resolution melting (MS-HRM) analysis was used for identification of NFATC1 and FOS genes methylation. The NFATC1 gene was methylated in 11 of the 35 postmenopausal women, and the FOS gene was methylated in six of the postmenopausal women (p >0.005). Here, we found statistically significant association between unmethylation of the NFATC1 gene and postmenopausal status. This result explains the epigenetic regulation of osteoclasts during the menopausal transition, and for the first time, our results can be used for epigenetic explanation of postmenopausal osteoporosis in the literature. However, the limited number of studies in this field makes our results crucial. Our results showed great value of epigenetic profiles of postmenopausal women.

Thyroid-stimulating hormone decreases the risk of osteoporosis by regulating osteoblast proliferation and differentiation

BACKGROUND

As the incidence of secretory osteoporosis has increased, bone loss, osteoporosis and their relationships with thyroid-stimulating hormone (TSH) have received increased attention. In this study, the role of TSH in bone metabolism and its possible underlying mechanisms were investigated.

METHODS

We analyzed the serum levels of free triiodothyronine (FT3), free thyroxine (FT4), and TSH and the bone mineral density (BMD) levels of 114 men with normal thyroid function. In addition, osteoblasts from rat calvarial samples were treated with different doses of TSH for different lengths of time. The related gene and protein expression levels were investigated.

RESULTS

A comparison of the BMD between the high-level and low-level serum TSH groups showed that the TSH serum concentration was positively correlated with BMD. TSH at concentrations of 10 mU/mL and 100 mU/mL significantly increased the mRNA levels of ALP, COI1 and Runx2 compared with those of the control (P < 0.05, P < 0.01). Bone morphogenetic protein (BMP)2 activity was enhanced with both increased TSH concentration and increased time. The protein levels of Runx2 and osterix were increased in a dose-dependent manner.

CONCLUSIONS

The circulating concentrations of TSH and BMD were positively correlated with normal thyroid function in males. TSH promoted osteoblast proliferation and differentiation in rat primary osteoblasts.

A Novel Hypothesis: A Role for Follicle Stimulating Hormone in Abdominal Aortic Aneurysm Development in Postmenopausal Women

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta, which can potentially be fatal due to exsanguination following rupture. Although AAA is less prevalent in women, women with AAA have a more severe AAA progression compared to men as reflected by enhanced aneurysm growth rates and a higher rupture risk. Women are diagnosed with AAA at an older age than men, and in line with increased osteoporosis and cardiovascular events, the delayed AAA onset has been attributed to the reduction of the protective effect of oestrogens during the menopausal transition. However, new insights have shown that a high follicle stimulating hormone (FSH) level during menopause may also play a key role in those diseases. In this report we hypothesize that FSH may aggravate AAA development and progression in postmenopausal women via a direct and/or indirect role, promoting aorta pathology. Since FSH receptors (FSHR) are reported on many other cell types than granulosa cells in the ovaries, it is feasible that FSH stimulation of FSHR-bearing cells such as aortic endothelial cells or inflammatory cells, could promote AAA formation directly. Indirectly, AAA progression may be influenced by an FSH-mediated increase in osteoporosis, which is associated with aortic calcification. Also, an FSH-mediated decrease in cholesterol uptake by the liver and an increase in cholesterol biosynthesis will increase the cholesterol level in the circulation, and subsequently promote aortic atherosclerosis and inflammation. Lastly, FSH-induced adipogenesis may lead to obesity-mediated dysfunction of the microvasculature of the aorta and/or modulation of the periaortic adipose tissue. Thus the long term increased plasma FSH levels during the menopausal transition may contribute to enhanced AAA disease in menopausal women and could be a potential novel target for treatment to lower AAA-related events in women.

Follicle-Stimulating Hormone Induces Lipid Droplets via Gαi/o and β-Arrestin in an Endometrial Cancer Cell Line

Follicle-stimulating hormone (FSH) and its G protein-coupled receptor, FSHR, represents a paradigm for receptor signaling systems that activate multiple and complex pathways. Classically, FSHR activates Gαs to increase intracellular levels of cAMP, but its ability to activate other G proteins, and β-arrestin-mediated signaling is well documented in many different cell systems. The pleiotropic signal capacity of FSHR offers a mechanism for how FSH drives multiple and dynamic downstream functions in both gonadal and non-gonadal cell types, including distinct diseases, and how signal bias may be achieved at a pharmacological and cell system-specific manner. In this study, we identify an additional mechanism of FSH-mediated signaling and downstream function in the endometrial adenocarcinoma Ishikawa cell line. While FSH did not induce increases in cAMP levels, this hormone potently activated pertussis toxin sensitive Gαi/o signaling. A selective allosteric FSHR ligand, B3, also activated Gαi/o signaling in these cells, supporting a role for receptor-mediated activation despite the low levels of FSHR mRNA. The low expression levels may attribute to the lack of Gαs/cAMP signaling as increasing FSHR expression resulted in FSH-mediated activation of the Gαs pathway. Unlike prior reports for FSH-mediated Gαs/cAMP signaling, FSH-mediated Gαi/o signaling was not affected by inhibition of dynamin-dependent receptor internalization. While chronic FSH did not alter cell viability, FSH was able to increase lipid droplet size. The β-arrestins are key adaptor proteins known to regulate FSHR signaling. Indeed, a rapid, FSH-dependent increase in interactions between β-arrestin1 and Gαi1 was observed via NanoBiT complementation in Ishikawa cells. Furthermore, both inhibition of Gαi/o signaling and siRNA knockdown of β-arrestin 1/2 significantly reduced FSH-induced lipid droplet accumulation, implying a role for a Gαi/o/β-arrestin complex in FSH functions in this cell type. As FSH/FSHR has been implicated in distinct hormone-dependent cancers, including endometrial cancer, analysis of the cancer genome database from 575 human endometrial adenocarcinoma tumors revealed that a subpopulation of samples expressed FSHR. Overall, this study highlights a novel mechanism for FSHR signal pleiotropy that may be exploited for future personalized therapeutic approaches.

Monitoring and maintaining bone health in patients with Turner syndrome

INTRODUCTION

Subjects affected with Turner Syndrome (TS) suffer low bone mineral density and high risk of fracture from a young age. Estrogen deficiency is considered the main risk factor but other factors, such as intrinsic bone abnormalities, enhanced osteoclastogenesis, vitamin D deficiency and other comorbidities may contribute to the exalted bone fragility.

AREAS COVERED

The authors performed a literature search in PubMed and EMBASE, using selected key words. They focused their search on pathogenetic mechanisms of osteoporosis in TS and updated the diagnosis, prevention and therapeutic interventions.

EXPERT OPINION

Bone health is a concern in subjects with TS, and strategies to prevent osteoporosis and fractures should be considered from childhood. Advice on how to live a healthy lifestyle, including physical activity and correct nutrition, should be given during childhood in order to prevent bone impairment later in life. The screening for vitamin D deficiency should be performed between the ages of 9 and 11, and every 2-3 years thereafter. Early initiation of estrogen replacement therapy (ERT) between 11-12 years of age, prompt titration to the adult dose after 2 years, and long-term follow-up to guarantee compliance with ERT, are the key points of osteoporosis prevention in women with TS.

First-in-class humanized FSH blocking antibody targets bone and fat

Blocking the action of FSH genetically or pharmacologically in mice reduces body fat, lowers serum cholesterol, and increases bone mass, making an anti-FSH agent a potential therapeutic for three global epidemics: obesity, osteoporosis, and hypercholesterolemia. Here, we report the generation, structure, and function of a first-in-class, fully humanized, epitope-specific FSH blocking antibody with a K _D of 7 nM. Protein thermal shift, molecular dynamics, and fine mapping of the FSH-FSH receptor interface confirm stable binding of the Fab domain to two of five receptor-interacting residues of the FSHβ subunit, which is sufficient to block its interaction with the FSH receptor. In doing so, the humanized antibody profoundly inhibited FSH action in cell-based assays, a prelude to further preclinical and clinical testing.

Fusion Potential of Human Osteoclasts In Vitro Reflects Age, Menopause, and In Vivo Bone Resorption Levels of Their Donors-A Possible Involvement of DC-STAMP

It is well established that multinucleation is central for osteoclastic bone resorption. However, our knowledge on the mechanisms regulating how many nuclei an osteoclast will have is limited. The objective of this study was to investigate donor-related variations in the fusion potential of in vitro-generated osteoclasts. Therefore, CD14⁺ monocytes were isolated from 49 healthy female donors. Donor demographics were compared to the in vivo bone biomarker levels and their monocytes’ ability to differentiate into osteoclasts, showing that: (1) C-terminal telopeptide of type I collagen (CTX) and procollagen type I N-terminal propeptide (PINP) levels increase with age, (2) the number of nuclei per osteoclast in vitro increases with age, and (3) there is a positive correlation between the number of nuclei per osteoclast in vitro and CTX levels in vivo. Furthermore, the expression levels of the gene encoding dendritic cell-specific transmembrane protein (DCSTAMP) of osteoclasts in vitro correlated positively with the number of nuclei per osteoclast, CTX levels in vivo, and donor age. Our results furthermore suggest that these changes in gene expression may be mediated through age-related changes in DNA methylation levels. We conclude that both intrinsic factors and age-induced increase in fusion potential of osteoclasts could be contributing factors for the enhanced bone resorption in vivo, possibly caused by increased expression levels of DCSTAMP.

Roles of follicle stimulating hormone and its receptor in human metabolic diseases and cancer

Follicle stimulating hormone (FSH) and its receptor (FSHR) play an important role in human metabolic diseases and cancer. Evidence showed that FSHR is not only distributed in ovary and testis but also in other cells or organs such as osteoclast, adipocytes, liver, pituitary cancer and so forth. Moreover, FSH is associated with lipogenesis, inflammation, insulin sensitivity, thermogenesis, skeletal metabolism, osteogenesis and ovarian cancer, all of which have been confirmed closely related to metabolic diseases or metabolic-related cancer. Therefore, FSH and FSHR may be potential therapeutic targets for metabolic diseases and metabolic-related cancer. Epidemiological researches revealed close relationship between FSH/FSHR and metabolic diseases or cancer. Experimental studies elucidated the underlying mechanism both in vivo and in vitro. We reviewed the recent researches and present an integrated framework of FSH/FSHR and metabolic diseases and cancer, which provides potential targets for the treatments of metabolic diseases and cancer.

Aging and menopause reprogram osteoclast precursors for aggressive bone resorption

Women gradually lose bone from the age of ~35 years, but around menopause, the rate of bone loss escalates due to increasing bone resorption and decreasing bone formation levels, rendering these individuals more prone to developing osteoporosis. The increased osteoclast activity has been linked to a reduced estrogen level and other hormonal changes. However, it is unclear whether intrinsic changes in osteoclast precursors around menopause can also explain the increased osteoclast activity. Therefore, we set up a protocol in which CD14+ blood monocytes were isolated from 49 female donors (40-66 years old). Cells were differentiated into osteoclasts, and data on differentiation and resorption activity were collected. Using multiple linear regression analyses combining in vitro and in vivo data, we found the following: (1) age and menopausal status correlate with aggressive osteoclastic bone resorption in vitro; (2) the type I procollagen N-terminal propeptide level in vivo inversely correlates with osteoclast resorption activity in vitro; (3) the protein level of mature cathepsin K in osteoclasts in vitro increases with age and menopause; and (4) the promoter of the gene encoding the dendritic cell-specific transmembrane protein is less methylated with age. We conclude that monocytes are "reprogrammed" in vivo, allowing them to "remember" age, the menopausal status, and the bone formation status in vitro, resulting in more aggressive osteoclasts. Our discovery suggests that this may be mediated through DNA methylation. We suggest that this may have clinical implications and could contribute to understanding individual differences in age- and menopause-induced bone loss.

FSH-metabolic circuitry and menopause

FSH has a primary function in procreation, wherein it induces estrogen production in females and regulates spermatogenesis in males. However, in line with our discoveries over the past decade of non-unitary functions of pituitary hormones, we and others have described hitherto uncharacterized functions of FSH. Through high-affinity receptors, some of which are variants of the ovarian FSH receptor (FSHR), FSH regulates bone mass, adipose tissue function, energy metabolism, and cholesterol production in both sexes. These newly described actions of FSH may indeed be relevant to the pathogenesis of bone loss, dysregulated energy homeostasis, and disordered lipid metabolism that accompany the menopause in females and aging in both genders. We are therefore excited about the possibility of modulating circulating FSH levels toward a therapeutic benefit for a host of age-associated diseases, including osteoporosis, obesity and dyslipidemia, among other future possibilities.

Osteoporosis from an Endocrine Perspective: The Role of Hormonal Changes in the Elderly

Introduction: Osteoporosis is increasingly prevalent in the elderly, with fractures mostly occurring in women and men who are older than 55 and 65 years of age, respectively. The aim of this review was to examine the evidence regarding the influence of hormones on bone metabolism, followed by clinical data of hormonal changes in the elderly, in the attempt to provide possible poorly explored diagnostic and therapeutic candidate targets for the management of primary osteoporosis in the aging population. Material and methods: An extensive Medline search using PubMed, Embase, and Cochrane Library was performed. Results: While the rise in Thyroid-stimulating hormone (TSH) levels has a protective role on bone mass, the decline of estrogen, testosterone, Insulin-like growth factor 1 (IGF1), and vitamin D and the rise of cortisol, parathyroid hormone, and follicle-stimulating hormone (FSH) favor bone loss in the elderly. Particularly, the AA rs6166 FSH receptor (FSHR) genotype, encoding for a more sensitive FSHR than that encoded by the GG one, is associated with low total body mass density (BMD), independently of circulating estrogen. A polyclonal antibody with a FSHR-binding sequence against the β-subunit of murine FSH seems to be effective in ameliorating bone loss in ovariectomized mice. Conclusions: A complete hormonal assessment should be completed for both women and men during bone loss evaluation. Novel possible diagnostic and therapeutic tools might be developed for the management of male and female osteoporosis.

FSH Beyond Fertility

The traditional view of follicle-stimulating hormone (FSH) as a reproductive hormone is changing. It has been shown that FSH receptors (FSHRs) are expressed in various extra-gonadal tissues and mediate the biological effects of FSH at those sites. Molecular, animal, epidemiologic, and clinical data suggest that elevated serum FSH may play a significant role in the evolution of bone loss and obesity, as well as contributing to cardiovascular and cancer risk. This review summarizes recent data on FSH action beyond reproduction.

Sex hormone levels by presence and severity of cirrhosis in women with chronic hepatitis C virus infection

Cirrhosis is associated with hormonal dysregulation, as evidenced by secondary amenorrhoea in reproductive-aged women, and feminization of cirrhotic men. Whether hormone levels vary by severity of cirrhosis in women is not known. If identified, such changes may have important clinical relevance, particularly, as low sex hormone binding globulin (SHBG) and follicle stimulating hormone (FSH) are known to promote metabolic and cardiovascular disease in women. In a cohort of post-menopausal women with chronic hepatitis C virus (HCV) infection, we compared comprehensive sex hormone levels by presence of cirrhosis, as well as across Child-Turcotte-Pugh (CTP) class. Results: There were n = 18 cirrhotic and n = 21 noncirrhotic women with a median age of 57 years (interquartile range [IQR] 53-62). Compared to noncirrhotics, cirrhotic women had higher oestradiol (11.0 vs 6.0 pg/mL, P = 0.05) and oestrone levels (32.0 vs 8.0 ng/mL, P < 0.001), and lower sex hormone binding globulin (SHBG) (69.2 vs 155.6 nmol/L, P = 0.001), and FSH levels (4.9 vs 89.6 mIU/mL, P < 0.001). Among cirrhotic women, there was a progressive decline in FSH and SHBG and concurrent rise in oestrone levels from CTP class A to C (test of trend, P values ≤0.02). Cirrhosis is associated with lower FSH and SHBG levels in cirrhotic compared to noncirrhotic women with HCV infection. In cirrhotic women, these levels demonstrate steady decline by disease severity. Given known associations of low SHBG and FSH with cardio-metabolic disease, the clinical implications of hormonal changes by cirrhosis severity in HCV-infected women warrants investigation.

Screening pathways and hub genes involved in osteoclastogenesis by gene expression analysis of circulating monocytes based on Gibbs sampling

Differential expression pathways and hub genes in circulating monocytes from healthy Chinese women with high peak bone mass (PBM) vs. low PBM were explored using a Markov chain Monte Carlo (MCMC) algorithm. Human circulating monocytes transcription profiling (containing 14 samples with high PBM and 12 samples with low PBM) and KEGG pathways were all downloaded from the public database. Initial state of all the pathways were constructed and Gibbs sampling was performed to obtain a Markov chain and the posterior values of all the pathways were calculated. The probability (α) of occurrence of each pathway was calculated based on the posterior value and it was adjusted by taking gene expression variation into account. Pathways with α_adj >0.8 were considered as differentially expressed pathways. Then, these steps were performed again on all the genes in the differentially expressed pathways to find the hub genes in the differential pathways. After Gibbs sampling, neuroactive ligand-receptor interaction (hsa04080) with α_adj = 0.986 was screened out as the differentially expressed pathway. Analyzing the genes in this pathway, three genes (neurotensin, tachykinin receptor 3 and follicle-stimulating hormone receptor) with α_adj >0.8 were identified as hub genes in circulating monocytes which may associate with osteoporosis development. One pathway and three genes which may possess close relationship with osteoporosis development were found in this study. These results provide insights into our understanding of the role of circulating monocytes in osteoporosis development.

FSH, Bone Mass, Body Fat, and Biological Aging

The Study of Women's Health Across the Nation has taught us that impending ovarian failure during late perimenopause is associated with a sharp rise in serum FSH, which coincides with the most rapid rate of bone loss and the onset of visceral adiposity. At this time in a woman's life, serum estrogen levels are largely unaltered, so the hypothesis that hypoestrogenemia is the sole cause of bone loss and visceral obesity does not offer a full explanation. An alternative explanation, arising from animal models and human data, is that both physiologic aberrations, obesity and osteoporosis, arise at least in part from rising FSH levels. Here, we discuss recent findings on the mechanism through which FSH exerts biological actions on bone and fat and review clinical data that support a role for FSH in causing osteoporosis and obesity. We will also provide a conceptual framework for using a single anti-FSH agent to prevent and treat both osteoporosis and obesity in women across the menopausal transition.

Effect of Black Tea Extract and Thearubigins on Osteoporosis in Rats and Osteoclast Formation in vitro

Background: Osteoporosis is a major health problem that is closely related to substantial morbidity, mortality and decline in life quality for the aging population. Although previous studies and epidemiological evidence have demonstrated an association between black tea consumption and the prevention of bone loss, the underlying mechanism remains unclear. So, the effect of black tea extract (BTE) and thearubigins (TRs) on osteoporosis in rats and osteoclast formation in vitro were investigated.

Methods:In vivo, ovariectomized (OVX) rats were used to establish osteoporosis models. To validate the model and study the effects of BTE and TRs on osteoporosis, the female Wistar rats were divided into a sham-operated group and five OVX groups including model, Xian-Ling-Gu-Bao (XLGB) (as a positive control), BTE, TRs low-dose, and TRs high-dose group. The rats in the four treatment groups were given the corresponding test sample for 12 weeks. Then, the body weight, femur indices, and serum biomarkers were examined and analyzed. In vitro, RAW264.7 murine macrophages were used as model of osteoclast formation. The effects of BTE and TRs on osteoclasts formation and the specific genes and protein levels of osteoclasts were determined.

Results: Although there was no significant effect on the OVX-induced body weight gain by BTE or TRs, the levels of maximum bending force, cortical bone thickness and biomarker of bone resorption (acid phosphatase) can be significantly ameliorated by BTE or TRs in OVX rats. Furthermore, both of BTE and TRs can inhibit the osteoclastogenesis and diminish the expression levels of the related genes and proteins.

Actions of pituitary hormones beyond traditional targets

Studies over the past decade have challenged the long-held belief that pituitary hormones have singular functions in regulating specific target tissues, including master hormone secretion. Our discovery of the action of thyroid-stimulating hormone (TSH) on bone provided the first glimpse into the non-traditional functions of pituitary hormones. Here we discuss evolving experimental and clinical evidence that growth hormone (GH), follicle-stimulating hormone (FSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin and arginine vasopressin (AVP) regulate bone and other target tissues, such as fat. Notably, genetic and pharmacologic FSH suppression increases bone mass and reduces body fat, laying the framework for targeting the FSH axis for treating obesity and osteoporosis simultaneously with a single agent. Certain 'pituitary' hormones, such as TSH and oxytocin, are also expressed in bone cells, providing local paracrine and autocrine networks for the regulation of bone mass. Overall, the continuing identification of new roles for pituitary hormones in biology provides an entirely new layer of physiologic circuitry, while unmasking new therapeutic targets.

Structure-Function Relationships of the Follicle-Stimulating Hormone Receptor

The follicle-stimulating hormone receptor (FSHR) plays a crucial role in reproduction. This structurally complex receptor is a member of the G-protein coupled receptor (GPCR) superfamily of membrane receptors. As with the other structurally similar glycoprotein hormone receptors (the thyroid-stimulating hormone and luteinizing hormone-chorionic gonadotropin hormone receptors), the FSHR is characterized by an extensive extracellular domain, where binding to FSH occurs, linked to the signal specificity subdomain or hinge region. This region is involved in ligand-stimulated receptor activation whereas the seven transmembrane domain is associated with receptor activation and transmission of the activation process to the intracellular loops comprised of amino acid sequences, which predicate coupling to effectors, interaction with adapter proteins, and triggering of downstream intracellular signaling. In this review, we describe the most important structural features of the FSHR intimately involved in regulation of FSHR function, including trafficking, dimerization, and oligomerization, ligand binding, agonist-stimulated activation, and signal transduction.

The Relationship between Follicle-stimulating Hormone and Bone Health: Alternative Explanation for Bone Loss beyond Oestrogen?

Bone loss in women commences before the onset of menopause and oestrogen deficiency. The increase of follicle-stimulating hormone (FSH) precedes oestrogen decline and may be a cause for bone loss before menopause. This review summarizes the current evidence on the relationship between FSH and bone derived from cellular, animal and human studies. Cellular studies found that FSH receptor (FSHR) was present on osteoclasts, osteoclast precursors and mesenchymal stem cells but not osteoblasts. FSH promoted osteoclast differentiation, activity and survival but exerted negligible effects on osteoblasts. Transgenic FSHR or FSH knockout rodents showed heterogenous skeletal phenotypes. Supplementation of FSH enhanced bone deterioration and blocking of FSH action protected bone of rodents. Human epidemiological studies revealed a negative relationship between FSH and bone health in perimenopausal women and elderly men but the association was attenuated in postmenopausal women. In conclusion, FSH may have a direct action on bone health independent of oestrogen by enhancing bone resorption. Its effects may be attenuated in the presence of overt sex hormone deficiency. More longitudinal studies pertaining to the effects of FSH on bone health, especially on fracture risk, should be conducted to validate this speculation.

Complex Association of Sex Hormones on Left Ventricular Systolic Function: Insight into Sexual Dimorphism

BACKGROUND

Normal values of left ventricular ejection fraction (LVEF) and absolute values of global longitudinal strain (GLS) are lower in men than in women. Data concerning the association of sex hormone levels on these left ventricular systolic function surrogates are scarce. The aim of this study was to determine the association of sex hormones with systolic left ventricular function in healthy subjects and patients with congenital adrenal hyperplasia (CAH) as a model of testosterone dysregulation.

METHODS

Eighty-four adult patients with CAH (58 women; median age, 27 years; interquartile range, 23-36 years) and 84 healthy subjects matched for sex and age were prospectively included. Circulating concentrations of sex hormones were measured within 48 hours of echocardiography with assessment of LVEF and left ventricular longitudinal, radial, and circumferential strain.

RESULTS

LVEF and GLS were higher in healthy women than in healthy men (63.9 ± 4.2% vs 60.9 ± 5.1% [P < .05] and 20.0 ± 1.9% vs 17.9 ± 2.4% [P < .001], respectively), while there was no difference in LVEF or GLS between women and men with CAH (63.9 ± 4.5% vs 63.0 ± 4.6% [P = NS] and 19.4 ± 2.2% vs 18.3 ± 1.8% [P = NS], respectively). Bioavailable testosterone levels were higher in women with CAH than in female control subjects (0.08 ng/mL [interquartile range, 0.04-0.14 ng/mL] vs 0.16 ng/mL [interquartile range, 0.04-0.3 ng/mL], P < .001) and lower in men with CAH than in male control subjects (2.3 ng/mL [interquartile range, 1.3-3 ng/mL] vs 2.9 ng/mL [interquartile range, 2.5-3.4 ng/mL], P < .05). In men, LVEF and GLS were negatively correlated with bioavailable testosterone levels (r = -0.3, P ≤ .05, and r = -0.45, P < .01, respectively), while midventricular radial strain was positively correlated with bioavailable testosterone level (r = 0.38, P < .05). The absolute value of circumferential strain was positively correlated with follicle-stimulating hormone (r = 0.65, P < .0001).

CONCLUSIONS

These data support that the existence of sex dimorphism concerning left ventricular systolic cardiac function is significantly associated with testosterone levels.

The relationship between postmenopausal women's sclerostin levels and their bone density, age, body mass index, hormonal status, and smoking and consumption of coffee and dairy products

PURPOSE

To investigate the relationship between postmenopausal women's sclerostin levels and bone density and the factors that may affect this relationship.

MATERIALS AND METHODS

135 postmenopausal patients' ages, BMIs, hormonal statuses, BMD values, and smoking, and consumption of coffee and dairy products were compared with their sclerostin levels.

RESULTS

No statistical relationship was found between sclerostin level and age in the group with osteoporosis (p = 0.204, r = -0.305). There was a positive, high-level relationship between sclerostin levels and BMI in the osteoporosis group and it was found to be statistically significant (p < 0.001, r = 0.786). No statistical relationship was found between sclerostin level and age in the non-osteoporosis group with (p = 0.496, r = -0.88). There was a positive, moderate relationship between sclerostin levels and BMI in the non-osteoporosis group and it was found to be statistically significant (p < 0.001, r = 0.505). No statistically significant relationship could be found between sclerostin levels and vitamin D (p = 0.723), PTH (p = 0.112), FSH (p = 0.795), E₂ (p = 0.627), TSH (p = 0.517), T₃ (p = 0.788), and T₄ (p = 0.664) blood levels. No significant difference was found among the groups formed by smoking, consumption of coffee and milk, and dairy products, either (p = 0.405; p = 0.626; p = 0.234, respectively). It was monitored that sclerostin's negative effect observed on BMD scores was independent from age; however, it had a positive correlation with BMI.

CONCLUSION

As blood sclerostin levels increase, bone mineral density decreases. This negative effect of sclerostin on bone density increases as BMI increases, too. Effects of sclerostin levels on bone density are independent from age, and they are not affect by levels of vitamin D: PTH, FSH, E₂ and thyroid hormones, and daily activities, such as smoking and consumption of coffee and milk and dairy products, either.

Featured Article: Transcriptional landscape analysis identifies differently expressed genes involved in follicle-stimulating hormone induced postmenopausal osteoporosis

Osteoporosis is a disorder associated with bone tissue reorganization, bone mass, and mineral density. Osteoporosis can severely affect postmenopausal women, causing bone fragility and osteoporotic fractures. The aim of the current study was to compare blood mRNA profiles of postmenopausal women with and without osteoporosis, with the aim of finding different gene expressions and thus targets for future osteoporosis biomarker studies. Our study consisted of transcriptome analysis of whole blood serum from 12 elderly female osteoporotic patients and 12 non-osteoporotic elderly female controls. The transcriptome analysis was performed with RNA sequencing technology. For data analysis, the edgeR package of R Bioconductor was used. Two hundred and fourteen genes were expressed differently in osteoporotic compared with non-osteoporotic patients. Statistical analysis revealed 20 differently expressed genes with a false discovery rate of less than 1.47 × 10-4 among osteoporotic patients. The expression of 10 genes were up-regulated and 10 down-regulated. Further statistical analysis identified a potential osteoporosis mRNA biomarker pattern consisting of six genes: CACNA1G, ALG13, SBK1, GGT7, MBNL3, and RIOK3. Functional ingenuity pathway analysis identified the strongest candidate genes with regard to potential involvement in a follicle-stimulating hormone activated network of increased osteoclast activity and hypogonadal bone loss. The differentially expressed genes identified in this study may contribute to future research of postmenopausal osteoporosis blood biomarkers.

Estrogen Receptor β as a Pharmaceutical Target

A major issue in clinical endocrinology today is how to use hormones to achieve the health benefits that they clearly can provide but avoid the negative side effects, that is, how to develop more precise medicines. This problem of how to use hormones is pervasive in clinical endocrinology. It is true for estrogen, progesterone, androgen, vitamin D, and thyroid hormone, and the problem is amplified in the case of new ligands for the more recently discovered nuclear receptors. Selective targeting of hormone receptor subtypes is one attractive way to harness the beneficial effects of hormones while reducing unwanted side effects. Here, we focus on estrogen receptor (ER)β, which has promise as a selective target in hormone replacement therapy, and in breast and prostate cancers.

Follicle-stimulating hormone enhances alveolar bone resorption via upregulation of cyclooxygenase-2

This study aimed to investigate whether follicle-stimulating hormone (FSH)-induced alveolar bone resorption was mediated by a cyclooxygenase 2 (COX-2) enzyme related mechanism. Experimental periodontitis was induced in bilateral ovariectomized (OVX) rats, some of which were injected with triptorelin, an FSH inhibitor. After mandibles were collected, we performed micro-computed tomography to evaluate alveolar bone loss and immunohistochemical staining to assess COX-2 expression. As well, human periodontal ligament cells (PDLCs) were treated with FSH (30 ng/ml), and the COX-2 mRNA and protein expression levels were measured by quantitative real-time polymerase chain reaction (qPCR) and Western blotting, respectively; prostaglandin E2 (PGE₂) levels were measured by enzyme-linked immunosorbent assay (ELISA). The results indicated that FSH significantly increased alveolar bone resorption and the expression of COX-2 in the bilateral OVX + Ligatured rats compared with the other treatment groups. FSH also increased the mRNA and protein expression of COX-2 and PGE₂ (P < 0.01) in human PDLCs. Further, the analysis of signaling pathways revealed the activation of COX-2-mediated pathways including Erk, p38, and Akt. These data suggest that FSH aggravates alveolar bone loss via a COX-2-upregulation mechanism and that the Erk, p38, and Akt pathways are involved in this pathological process.

FSH Levels Predict Bone Loss in Premenopausal Women Treated for Breast Cancer More Than One Year After Treatment

CONTEXT

Biomarkers to predict bone loss in premenopausal women after breast cancer treatment have not been examined.

OBJECTIVE

To determine whether baseline FSH predicts subsequent bone loss.

DESIGN

Secondary data analysis of the Exercise for Bone Health: Young Breast Cancer Survivors study, in which women were randomized to a 12-month exercise program or monthly health newsletter.

SETTING

Community dwelling women.

PARTICIPANTS

A total of 206 women age less than or equal to 55 years at breast cancer diagnosis who had received adjuvant chemotherapy and were at least 1 year after diagnosis.

INTERVENTION

Serum collected at baseline (an average of 302 ± 148 d after completing chemotherapy) was analyzed for FSH.

MAIN OUTCOME MEASURE

Change in bone mineral density.

RESULTS

In linear regression models, baseline FSH levels predicted bone loss over the ensuing 12 months at the lumbar spine and femoral neck including after adjustment for age, ethnicity, treatment group (exercise vs control), baseline bone density, and high-sensitivity C-reactive protein (P < .001). In multiply adjusted models, the 12-month rate of change in bone density was +0.007% in the lowest tertile of FSH (FSH = 9 ± 7 IU/L, mean ± SD), -0.96% in the middle tertile (mean FSH = 41 ± 11 IU/L), and -2.2% in the highest tertile (mean FSH = 86 ± 19 IU/L), P for trend <.001.

CONCLUSIONS

Among premenopausal women with breast cancer treated with chemotherapy, baseline FSH levels are strongly associated with subsequent bone loss. Further studies are needed to establish the optimal timing of FSH measurement in relation to breast cancer treatment and to investigate potential strategies to prevent bone loss.

Bone Mineral Status in Children and Adolescents with Klinefelter Syndrome

Objective. Klinefelter syndrome (KS) has long-term consequences on bone health. However, studies regarding bone status and metabolism during childhood and adolescence are very rare. Patients. This cross-sectional study involved 40 (mean age: 13.7 ± 3.8 years) KS children and adolescents and 80 age-matched healthy subjects. For both patient and control groups, we evaluated serum levels of ionised and total calcium, phosphate, total testosterone, luteinising hormone, follicle stimulating hormone, parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline concentrations. We also calculated the z-scores of the phalangeal amplitude-dependent speed of sound (AD-SoS) and the bone transmission time (BTT). Results. KS children and adolescents showed significantly reduced AD-SoS (p < 0.005) and BTT (p < 0.0005) z-scores compared to the controls. However, KS patients presented significantly higher PTH (p < 0.0001) and significantly lower 25(OH)D (p < 0.0001), osteocalcin (p < 0.05), and bone alkaline phosphatase levels (p < 0.005). Interestingly, these metabolic bone disorders were already present in the prepubertal subjects. Conclusions. KS children and adolescents exhibited impaired bone mineral status and metabolism with higher PTH levels and a significant reduction of 25-OH-D and bone formation markers. Interestingly, this impairment was already evident in prepubertal KS patients. Follow-ups should be scheduled with KS patients to investigate and ameliorate bone mineral status and metabolism until the prepubertal ages.