Sex steroids and the construction and conservation of the adult skeleton

Effect of eccentric-based resistance exercise on bone (re)modelling markers across the menstrual cycle and oral contraceptive cycle

PURPOSE

To investigate the acute effects of eccentric-based resistance exercise and sex-hormone fluctuations on P1NP and β-CTX-1 concentrations in premenopausal females.

METHODS

Nine eumenorrheic females and ten oral contraceptive (OC) users performed eccentric-based resistance exercise, consisted of 10 × 10 repetitions of parallel back squats with a 4-s eccentric phase, in the early-follicular (EFP), late-follicular (LFP) and mid-luteal (MLP) phases of the menstrual cycle (MC) or in the withdrawal (WP) and active pill-taking (APP) phases of the OC cycle.

RESULTS

17β-oestradiol (pg·ml-1) was lower in EFP (36.63 ± 29.93) compared to LFP (224.81 ± 233.81; p ≤ 0.001) and MLP (161.45 ± 110.08; p < 0.001) and higher in WP (24.857 ± 29.428) compared to APP (12.72 ± 13.36; p = 0.004). Progesterone (ng·ml-1) was higher in MLP (8.30 ± 5.23) compared to EFP (0.33 ± 0.33; p < 0.001) and LFP (0.21 ± 0.18; p < 0.001), no significant differences were observed between the WP and APP. In eumenorrheic females, β-CTX-1 (ng·ml-1) was lower in MLP (0.395 ± 0.126) compared to LFP (0.472 ± 0.137; p = 0.044). Comparing MC vs OC phases, eumenorrheic females had higher P1NP levels (ng·ml-1) compared to OC users: EFP (62.54 ± 13.13) vs APP (50.69 ± 8.91; p = 0.034), LFP (67.32 ± 18.96) vs WP (52.16 ± 10.72; p = 0.047), LFP vs APP (p = 0.025), MLP (67.51 ± 19.34; p = 0.049) vs WP, MLPvsAPP (p = 0.027). Exercise time effect showed lower β-CTX-1 concentrations 2 h post-exercise (MC: 0.376 ± 0.114, p < 0.001; OC: 0.340 ± 0.156, p = 0.030) compared to pre-exercise (MC: 0.485 ± 0.137; OC: 0.428 ± 0.188) in all participants.

CONCLUSIONS

β-CTX-1 concentrations were lower in the mid-luteal phase, emphasising the importance of standardizing bone marker measurements to a specific MC phase. OC users exhibited reduced P1NP levels, underscoring the need to investigate synthetic and endogenous hormones' impact on long-term bone structure and strength. Trial registration The study was registered at Clinicaltrials.gov NCT04458662 on 2 July 2020.

L-shaped association of bone mineral density with all-cause mortality in individuals with osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a common joint disease that poses a significant public health burden, particularly in older adults. Despite research on its impact, the role of bone mineral density (BMD) in OA prognosis remains underexplored. This study investigates the association between BMD, measured using dual-energy X-ray absorptiometry (DXA), and all-cause mortality in individuals with OA using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

This retrospective cohort study utilized NHANES data from 1999 to 2018, including participants aged 20 years and older (n = 55,081). After excluding individuals with missing BMD or mortality data, 1,573 participants diagnosed with OA were analyzed.

RESULTS

The multivariate-adjusted hazard ratio (HR) for BMD and all-cause mortality was 0.344 (0.153, 0.774), indicating a protective effect of higher BMD. We observed an L-shaped relationship between BMD and mortality: a 1-unit decrease in BMD was associated with a 97.3% increased HR for mortality when BMD was below 1.216 g/cm² (HR 0.027, 95% CI 0.010-0.069). No significant association was found for higher BMD levels (HR 4.490, 95% CI 0.431-46.754). In age-stratified analysis, a significant association was found in both those under and over 50 years old.

CONCLUSIONS

This study reveals an L-shaped association between BMD and all-cause mortality in individuals aged 20 and older with OA, underscoring the importance of maintaining bone health in this population. These findings highlight BMD as a prognostic marker and suggest that monitoring BMD could improve clinical outcomes for OA patients.

CLINICAL TRIAL NUMBER

Not applicable.

The Determinants of Bone Health in Children With Autism Spectrum Disorder: A Systematic Narrative Review

Autism spectrum disorder (ASD) is a complex disorder associated with social and communication impairments and repetitive and restrictive behavioural patterns. Children with ASD often present with concurrent conditions, including poor bone health, which affect long-term health. Although there is compelling evidence to suggest that children with ASD have poorer bone traits than typically developing children, the primary factors associated with these differences are unclear. This review will explore the potential role that factors such as physical activity, nutrition (calcium, protein, vitamin C, vitamin D) and lifestyle (sleep, medication) play on bone health in children with ASD. Having a greater understanding of the influencing factors of low BMD and how these might interact in a synergistic manner in ASD children will provide an opportunity to develop targeted interventions to improve bone health aiming to avert attainment of suboptimal peak bone mass which may lead to early onset osteoporosis, fracture and muscle deconditioning in this paediatric population.

Comparative assessment of flavonoid content in banana pulp and peel and their role in mitigating bone loss conditions and promoting osteoblast differentiation

Banana fruit is widely grown and serves as a source of income across the tropics. It is known for its nutritional qualities and well-recognized medicinal applications. Given that banana pulp and peel are rich in flavonoids, such as naringenin, kaempferol, and quercetin, which are already known for their role in bone health, we hypothesize that banana pulp and peel can accelerate fracture healing, mitigate bone loss in post-menopausal conditions, and promote osteoblast differentiation. The current study was proposed to assess a comparative and parallel investigation of the differential flavonoid expression in banana pulp and peel and their concomitant bone anabolic effects. The pulp extract exhibited its osteogenic potential when administered orally for 2 weeks at doses of 250, 500 and 750 mg per kg per day in the osteotomy Balb/c mice model (n = 10), while the peel extract showed similar effects at comparatively much lower doses of 50, 100 and 250 mg per kg per day for the same duration. The effective lower doses in both cases, i.e., 250 mg per kg per day for the pulp and 50 mg per kg per day for the peel, were used to further investigate the anti-osteoporotic potential in vivo over a span of 8 weeks (n = 10). Banana pulp ameliorated the microarchitectural deterioration of the bones by increasing the rate of bone formation while simultaneously limiting exaggerated resorption, as assessed by micro-CT, calcein labelling, TRAP staining, bone strength parameters and measurement of bone formation and resorption markers in serum. Similar results were obtained with the banana peel extract at considerably lower doses. The osteogenic potential of the pulp and peel extracts was also tested in an in vitro setup. Osteoblast viability and differentiation, as assessed by MTT, ALP, mineralization and RT-PCR, demonstrated that bone formation potential was observed at 2.5 μg ml-1 and 5 μg ml-1 of the pulp extract, whereas in the case of the peel extract, it was observed at 0.625 μg ml-1 and 1.25 μg ml-1. These findings indicate that banana peel can exert similar osteogenic and osteoprotective effects as the pulp but at a much lower dose. This highlights banana peel as a prospective, sustainable feedstock for the healthcare sector, providing an alternative to its disposal.

The Role of Sex Steroid Hormones in the Association Between Manganese Exposure and Bone Mineral Density: National Health and Nutrition Examination Survey 2013-2018

This study investigates the association between blood Mn and bone mineral density (BMD), focusing on the mediating role of sex steroids, using data from 8617 participants in the National Health and Nutrition Examination Survey (NHANES) 2013-2018. Weighted multiple linear regression models were used to examine the association of blood Mn and total BMD, and mediation analyses were used to explored the roles of total testosterone (TT), estradiol (E2), and sex hormone-binding globulin (SHBG) in the Mn-BMD relationship, stratified by sex and menopausal status. Blood Mn was negatively associated with BMD in both sexes, with a pronounced effect in postmenopausal women. SHBG mediated 37.16% of the Mn-BMD association in men, whereas no mediating effects were found in women. E2 exhibited a significant indirect effect, suggesting that reduced E2 levels may amplify Mn's effect on BMD. These findings indicate that Mn exposure is associated with decreased BMD, potentially through alterations in sex steroids, highlighting the importance of considering hormone status when evaluating the impact of Mn exposure on BMD.

Associations between hormones, metabolic markers, and bone mass in perimenopausal and postmenopausal women

INTRODUCTION

To explore the associations between hormones, metabolic markers, and low bone mass in perimenopausal and postmenopausal women.

MATERIALS AND METHODS

A total of 198 women were enrolled in this study. The correlations between hormones, metabolic markers, and BMD were analyzed. Risk factors for bone loss were identified. Receiver operating characteristic (ROC) curves were used to display the predictive power of these risk factors.

RESULTS

The years since menopause and the levels of glucose (GLU), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were inversely correlated with BMD, while estrogen and testosterone were positively correlated with BMD. Age (odds ratio [OR] 1.232; 95% confidence interval [CI] 1.106-1.372; p < 0.001), GLU (OR 1.848; 95% CI 1.116-3.059; p = 0.017), and FSH (OR 1.089; 95% CI 1.003-1.182; p = 0.042) were identified as risk factors for bone loss. Age (AUC = 0.884, 95% CI 0.833-0.935), FSH (AUC = 0.824, 95% CI 0.760-0.888), and GLU (AUC = 0.683, 95% CI 0.599-0.768) demonstrated significant discrimination capability for bone loss. The combined application of these factors resulted in a better prediction effect (AUC = 0.930, 95% CI 0.893-0.967).

CONCLUSIONS

Age, FSH, and GLU were found to be specific risk factors for bone loss. The utilization of these factors offers compelling predictive power for bone loss in perimenopausal and postmenopausal women.

Risk Factors and Awareness of Bone Fragility in Inflammatory Bowel Disease in Taiwan: A Cross-Sectional Study

Background/Objectives: Patients with inflammatory bowel disease (IBD) are at a higher risk of developing bone disorders. Awareness and understanding of the disease are crucial for prevention and early diagnosis. Currently, there is no research on the risk factors and knowledge of bone fragility in the population with IBD in Taiwan. This study aimed to evaluate the risk factors and self-assessed knowledge levels of bone health among patients with IBD in Taiwan. Methods: This single-center cross-sectional study included 59 adult patients. Clinical data, blood tests, bone mineral density (BMD), T-score, Z-score, and questionnaires covering self-assessed knowledge, fracture risks, and physical activity were assessed. The patients were divided into normal and low BMD groups. Results: Of all participants, eighteen (30.5%) had low BMD: six (10.2%) had BMD below the expected range, ten (16.9%) had osteopenia, and two (3.4%) had osteoporosis. Vitamin D insufficiency and deficiency were observed in 26.3% and 66.6% of the patients, respectively. According to multivariate analysis, age and sex hormone deficiency are strongly associated with low BMD. Educational interventions significantly improved the patients' self-assessed knowledge levels. Conclusions: Age and sex hormone deficiency are significant factors contributing to low BMD in IBD patients. Not only women but also men with IBD who had symptoms of hypogonadism are at high risk for low BMD. Educational interventions improve self-assessment knowledge regarding the relationship between IBD and bone health.

Chr23-miR-200s and Dmrt1 Control Sexually Dimorphic Trade-Off Between Reproduction and Growth in Zebrafish

In animals, a trade-off exists between reproduction and growth, which are the most fundamental traits. Males and females exhibit profound differences in reproduction and growth in fish species. However, the precise molecular mechanism governing this phenomenon is still not clear. Here, we uncovered that chr23-miR-200s and dmrt1 knockout specifically caused an impairment in reproduction and an increase in body growth in female and male zebrafish, respectively. Chr23-miR-200s and Dmrt1 directly regulate the stat5b gene by targeting its 3'UTR and promoter. The loss of stat5b completely abolished the elevated growth performance in chr23-miR-200s-KO or dmrt1-/- zebrafish. Moreover, the dmrt1 transgenic zebrafish had significantly lower body length and body weight than the control males, accompanied by a significant reduction in stat5b expression in the liver of transgenic fish. In summary, our study proposes a regulatory model elucidating the roles of chr23-miR-200s and Dmrt1 in controlling the sexually dimorphic trade-off between reproduction and growth.

Chronic Kidney Disease-Mineral Bone Disorder (CKD-MBD) in Pediatric Kidney Transplant Recipients

Kidney transplantation remains the gold standard treatment for end-stage kidney disease (ESKD), effectively alleviating numerous comorbidities and offering a substantial survival advantage over long-term dialysis. Despite advancements in immunosuppressive regimens and improvements in graft and patient survival rates, extended patient longevity brings an accumulating burden and complexity of bone disease in this population, which often goes underrecognized. The present study reviews the pathophysiology of CKD-MBD in pediatric KTR, focusing on the progression of bone disease before and after transplantation. We aim to enhance understanding of available screening options, highlighting their advantages and limitations, to support more informed decision-making in CKD-MBD management.

Osteoporosis: Causes, Mechanisms, Treatment and Prevention: Role of Dietary Compounds

Osteoporosis is a chronic disease that is characterized by a loss of bone density, which mainly affects the microstructure of the bones due to a decrease in bone mass, thereby making them more fragile and susceptible to fractures. Osteoporosis is currently considered one of the pandemics of the 21st century, affecting around 200 million people. Its most serious consequence is an increased risk of bone fractures, thus making osteoporosis a major cause of disability and even premature death in the elderly. In this review, we discuss its causes, the biochemical mechanisms of bone regeneration, risk factors, pharmacological treatments, prevention and the effects of diet, focusing in this case on compounds present in a diet that could have palliative and preventive effects and could be used as concomitant treatments to drugs, which are and should always be the first option. It should be noted as a concluding remark that non-pharmacological treatments such as diet and exercise have, or should have, a relevant role in supporting pharmacology, which is the recommended prescription today, but we cannot ignore that they can have a great relevance in the treatment of this disease.

Endothelial BMAL1 decline during aging leads to bone loss by destabilizing extracellular fibrillin-1

The occurrence of aging is intricately associated with alterations in circadian rhythms that coincide with stem cell exhaustion. Nonetheless, the extent to which the circadian system governs skeletal aging remains inadequately understood. Here, we noticed that skeletal aging in male mice was accompanied by a decline in a core circadian protein, BMAL1, especially in bone marrow endothelial cells (ECs). Using male mice with endothelial KO of aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1), we ascertained that endothelial BMAL1 in bone played a crucial role in ensuring the stability of an extracellular structural component, fibrillin-1 (FBN1), through regulation of the equilibrium between the extracellular matrix (ECM) proteases thrombospondin type 1 domain-containing protein 4 (THSD4) and metalloproteinase with thrombospondin motifs 4 (ADAMTS4), which promote FBN1 assembly and breakdown, respectively. The decline of endothelial BMAL1 during aging prompted excessive breakdown of FBN1, leading to persistent activation of TGF-β/SMAD3 signaling and exhaustion of bone marrow mesenchymal stem cells. Meanwhile, the free TGF-β could promote osteoclast formation. Further analysis revealed that activation of ADAMTS4 in ECs lacking BMAL1 was stimulated by TGF-β/SMAD3 signaling through an ECM-positive feedback mechanism, whereas THSD4 was under direct transcriptional control by endothelial BMAL1. Our investigation has elucidated the etiology of bone aging in male mice by defining the role of ECs in upholding the equilibrium within the ECM, consequently coordinating osteogenic and osteoclastic activities and retarding skeletal aging.

Cushing's Syndrome in the Elderly

Management of Cushing's syndrome (CS) can be particularly challenging in older patients, compared with younger individuals, due to the lack of several clinical features associated with cortisol excess along with a greater burden of associated comorbidities. Moreover, the interpretation of diagnostic tests could be influenced by age-related physiological changes in cortisol secretion. While mortality is higher and quality of life is more impaired in the elderly with CS as compared with the younger, there is currently no agreement on the most effective therapeutic options in aged individuals, and safety data concerning medical treatment are scanty. In this review, we summarize the current knowledge about age-related differences in CS etiology, clinical presentation, treatment, and outcomes and describe the potential underlying mechanisms.

Sensing the future: A review on emerging technologies for assessing and monitoring bone health

Bone health is crucial at all stages of life. Several medical conditions and changes in lifestyle affect the growth, structure, and functions of bones. This may lead to the development of bone degenerative disorders, such as osteoporosis, osteoarthritis, rheumatoid arthritis, etc., which are major public health concerns worldwide. Accurate and reliable measurement and monitoring of bone health are important aspects for early diagnosis and interventions to prevent such disorders. Significant progress has recently been made in developing new sensing technologies that offer non-invasive, low-cost, and accurate measurements of bone health. In this review, we have described bone remodeling processes and common bone disorders. We have also compiled information on the bone turnover markers for their use as biomarkers in biosensing devices to monitor bone health. Second, this review details biosensing technology for bone health assessment, including the latest developments in various non-invasive techniques, including dual-energy X-ray absorptiometry, magnetic resonance imaging, computed tomography, and biosensors. Further, we have also discussed the potential of emerging technologies, such as biosensors based on nano- and micro-electromechanical systems and application of artificial intelligence in non-invasive techniques for improving bone health assessment. Finally, we have summarized the advantages and limitations of each technology and described clinical applications for detecting bone disorders and monitoring treatment outcomes. Overall, this review highlights the potential of emerging technologies for improving bone health assessment with the potential to revolutionize clinical practice and improve patient outcomes. The review highlights key challenges and future directions for biosensor research that pave the way for continued innovations to improve diagnosis, monitoring, and treatment of bone-related diseases.

Air Pollution and Osteoporosis

PURPOSE OF REVIEW

The purpose of this review is to provide a background of osteoporosis and air pollution, discussing increasing incidence of the disease with exposure to pollutants and the role that inflammation may play in this process.

RECENT FINDINGS

Osteoporosis-related fractures are one of the most pressing challenges for the ageing global population, with significant increases in mortality known to occur after major osteoporotic fractures in the elderly population. Recent studies have established a firm correlative link between areas of high air pollution and increased risk of osteoporosis, particularly alarming given the increasingly urban global population. While the culprit pollutants and molecular mechanisms underlying this phenomenon have not yet been elucidated, initial studies suggest a role for inflammatory cascades in this phenomenon. While much more research is required to identify the most damaging air pollutants and to delineate the specific inflammatory molecular mechanisms, it is clear from the literature that shedding light on these pathways would unveil potential therapeutic targets to treat bone diseases, including osteoporosis. Major deficiencies of current animal models highlight the need for complex human in vitro models such as organ-on-a-chip technology to better understand the impact of air pollution.

How Does Physical Activity Modulate Hormone Responses?

Physical activity highly impacts the neuroendocrine system and hormonal secretion. Numerous variables, both those related to the individual, including genetics, age, sex, biological rhythms, nutritional status, level of training, intake of drugs or supplements, and previous or current pathologies, and those related to the physical activity in terms of type, intensity, and duration of exercise, or environmental conditions can shape the hormonal response to physical exercise. The aim of this review is to provide an overview of the effects of physical exercise on hormonal levels in the human body, focusing on changes in concentrations of hormones such as cortisol, testosterone, and insulin in response to different types and intensities of physical activity. Regular monitoring of hormonal responses in athletes could be a potential tool to design individual training programs and prevent overtraining syndrome.

Gastrointestinal health and serum proteins are associated with BMD in postmenopausal women: a cross-sectional study

BACKGROUND

With increasing age, the social and economic burdens of postmenopausal osteoporosis are steadily increasing. This study aimed to investigate the factors that influence the development of postmenopausal osteoporosis.

METHODS

Postmenopausal women at the Affiliated Hospital of Jiangnan University from January 2023 to December 2023 were recruited for BMD examination. The patients were divided into a normal group, an osteopenia group and an osteoporosis group according to their T value. Questionnaires, including the Gastrointestinal Symptom Rating Scale and Short Form 12, were administered through face-to-face interviews. Bone turnover markers and serum protein levels of Fasting venous blood were detected.

RESULTS

A total of 222 postmenopausal women met the inclusion criteria were recruited. Univariate analysis revealed statistically significant differences in age, education, BMI, supplementation with soy products, supplementation with dairy products, supplementation with other nutritional supplements, exercise frequency, gastrointestinal symptom score, quality of life, 25(OH)D, total protein, albumin and prealbumin among the three groups (P < 0.05). Pearson correlation analysis revealed that gastrointestinal symptoms (r = -0.518, P < 0.01) was negatively correlated with BMD in postmenopausal women, while PCS (r = 0.194, P = 0.004), MCS (r = 0.305, P < 0.01), 25(OH)D (r = 0.531, P < 0.01), total protein (r = 0.324, P < 0.01), albumin (r = 0.341, P < 0.01) and prealbumin (r = 0.259, P < 0.01) were positively correlated with BMD. Logistic regression analysis revealed that both the gastrointestinal symptom score and serum 25(OH)D level were found to have a significant association with BMD (both P < 0.01). This association remained significant even after adjusting for age, BMI, education level, dietary habits, and exercise frequency.

CONCLUSION

Gastrointestinal symptoms and serum 25(OH)D elevel are associated with increased risk of osteoporosis in postmenopausal women and may be useful in predicting osteoporosis in postmenopausal women.

Loss of Bone Density in Patients with Anorexia Nervosa Food That Alone Will Not Cure

BACKGROUND

Anorexia Nervosa is a highly lethal illness that is also associated with many medical complications. Food restriction and weight loss define this illness. Most of its physical complications are reversible with weight restoration, with the notable exception of the loss of bone density, which is commonly present in anorexia nervosa.

METHODS

A comprehensive scientific literature review was performed in order to explore bone disease in anorexia nervosa.

RESULTS

The pathophysiology of the loss of bone mineral density in anorexia nervosa was elucidated, along with the diagnosis and treatment of osteoporosis in patients with anorexia nervosa, including the nutritional approach to weight restoration.

CONCLUSIONS

Loss of bone mineral density in anorexia nervosa is very aggressive. Nutritional rehabilitation is a cornerstone to treating this, along with medicinal considerations.

Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running

To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and β-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17β-oestradiol, progesterone, P1NP and β-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17β-oestradiol concentrations (pg·ml-1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p =  < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml-1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml-1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). β-CTX-1 concentrations (ng·ml-1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.

The role of neuroestrogens in the estrogen-induced gonadotropin surge in male monkeys

Neuroestrogens locally synthesized in the brain are known to play a role in sexual behaviors. However, the question of whether neuroestrogens are involved in the regulation of the gonadotropin-releasing hormone (GnRH) release is just emerging. Because previous studies in this lab indicate that neuroestradiol is also important for the pulsatile release as well as the surge release of GnRH in female rhesus monkeys, in the present study, we examined whether neuroestradiol plays a role in the estrogen-induced LH surge in orchidectomized (ORX) male rhesus monkeys. Unlike in rodents, it is known that a high dose of estrogen treatment can result in the LH surge in ORX male rhesus monkeys. Results that the administration of the aromatase inhibitor, letrozole, failed to attenuate the estrogen-induced LH surge, suggest that unlike in ovariectomized females, neuroestrogens do not play a role in the LH surge experimentally induced by the exogenous estrogen treatment in ORX male monkeys.

Prevalence and Associated Factors of Musculoskeletal Disorders among Older Patients Treated at Walailak University Physical Therapy Clinic in Thailand: A Retrospective Study

The prevalence of musculoskeletal disorders (MSDs) is high among older adults worldwide, significantly affecting their quality of life and overall health. Understanding the prevalence of MSDs and their associated factors is crucial to developing effective preventive and management strategies in Thailand. In this study, we aimed to investigate the prevalence of MSDs and their associated factors among older patients at Walailak University Physical Therapy Clinic. In this retrospective study, we analyzed the medical records of 396 older patients. Data on demographics, underlying diseases, career types, and treatments were collected and analyzed using descriptive statistics chi-squared tests, and logistic regression analysis to determine their associations with MSD prevalence. The overall prevalence of MSDs was 89.90%. MSD prevalence was higher among female patients than among male patients (p < 0.001). The most commonly affected body regions were the lower back, shoulders, and knees. Career type (p < 0.001) had the highest impact on the presence of MSDs after controlling for sex, age, and underlying diseases as covariates in a logistic regression model. Manual labor and heavy industry workers as well as pensioners showed an increased risk of MSDs. While older age was associated with a higher MSD prevalence using chi-squared statistics, it was removed from the logistic regression models. Pensioners were the most likely to receive treatment, indicating the need for targeted interventions for individuals with physically demanding occupations. These findings underscore the importance of targeted interventions and further research on socioeconomic factors, lifestyle behaviors, and comorbidities to manage MSDs among older adults in Thailand.

Bone Loss and Fractures in Post-Menopausal Women Living with HIV: A Narrative Review

INTRODUCTION

Post-menopausal women living with Human Immunodeficiency Virus (WLHIV) face an increased risk of bone fractures due to the relationship between HIV-related factors and menopause. This narrative review aims to summarise the current knowledge about fracture risk among post-menopausal WLHIV in particular looking at hormonal changes, combined antiretroviral therapy (cART), lifestyle factors, and psychosocial implications. We also profiled a summary of the significant, recent studies of post-menopausal WLHIV residing in low-income countries (LIC).

METHODS

A thorough search of the literature was performed across PubMed, Medline, Scopus, and Google Scholar, focussing on studies published between 2000 and 2024. Inclusion criteria entailed original research, reviews, and meta-analyses addressing bone mineral density (BMD), fracture incidence, and related risk factors in post-menopausal WLHIV.

RESULTS

The review identified 223 relevant studies. Post-menopausal WLHIV exhibit significantly lower BMD and higher fracture rates compared to both HIV-negative post-menopausal women and pre-menopausal WLHIV. cART, particularly tenofovir disoproxil fumarate (TDF), contributes to reduced BMD. Menopausal status exacerbates this risk through decreased oestrogen levels, leading to increased bone resorption. Moreover, lifestyle choices such as smoking, alcohol consumption, and low physical activity are more prevalent in PWHIV, which further elevates fracture risk. Different psychosocial factors may make WLWHIV more vulnerable at this stage of their life, such as depression, isolation, stigma, and housing and nutritional issues. Women living in LICs face a variety of challenges in accessing HIV care. There are gaps in research related to the prevalence of osteoporosis and bone loss in post-menopausal WLHIV in LICs.

CONCLUSION

Post-menopausal women living with HIV face a significantly higher risk of bone loss and fractures due to the combined effects of HIV and menopause. Antiretroviral therapy (particularly TDF), lifestyle factors, and psychosocial challenges exacerbate this risk. There is a need for careful selection of cART, hormone replacement therapy (HRT), and emerging treatments such as Abaloparatide. A holistic approach including lifestyle changes and psychosocial support is crucial to reduce fracture risk in WLHIV, especially in low-income countries.

Causal relationship between reproductive factors and female bone density: a univariate and multivariate mendelian randomization study

Objective

Observational studies have found associations between reproductive factors and bone density in women. However, the causal relationships are not well understood. This study aims to investigate whether various reproductive factors are causally related to bone density at different skeletal sites using both univariable and multivariable Mendelian randomization (MR) methods.

Methods

The study incorporated four reproductive factors, namely, age at menarche (AAM), age at first live birth (AFB), age at menopause (ANM), and age at last live birth (ALB), as well as five distinct skeletal sites, including bone mineral density (BMD), heel calcaneus BMD, ultradistal forearm bone mineral density (FA-BMD), lumbar spine bone mineral density (LS-BMD), and femoral neck bone mineral density (FN-BMD). Univariable two-sample MR and multivariable MR analyses were conducted using data from published genome-wide association studies (GWASs). A total of 150 single nucleotide polymorphisms (SNPs) associated with the four reproductive factors were extracted from GWAS databases. The primary statistical analysis method utilized in this study was the inverse variance weighted (IVW) method.

Results

In the univariate MR analysis, we observed causal connections between four reproductive factors and bone density. Specifically, AAM had a significant impact on BMD and heel calcaneus BMD. Age at first live birth was negatively associated with FA-BMD. Age at last live birth showed a negative correlation with BMD and heel calcaneus BMD. ANM exhibited positive associations with BMD, heel calcaneus BMD, FA-BMD, and LS-BMD. Subsequently, we performed a multivariable MR analysis to examine the combined effects of multiple variables, which confirmed the persistence of associations between age at menopause and bone density at various sites. Additionally, we found a negative correlation between age at last live birth and heel calcaneus BMD.

Conclusion

This study offers a fresh perspective on the prevention of osteoporosis in women, explicitly stating that reproductive factors such as early menopause and late childbirth play a significant predictive role in individual bone density decline. Therefore, when developing osteoporosis screening and management protocols, reproductive factors should be included for a more comprehensive guidance of clinical practice.

Hyperostosis frontalis interna on fluorine-18 sodium fluoride PET/computed tomography of obese cancer patients: a potential mimicker of metastasis

OBJECTIVE

The objective of this retrospective study was to identify the uptake patterns and suggest a quantitative method to detect hyperostosis frontalis interna (HFI) on fluorine-18 sodium fluoride ([ 18 F]NaF) PET/computed tomography (CT).

METHODS

Between January 2019 and December 2021, patients who underwent [ 18 F]NaF PET/CT with a BMI of 30 and above, were included. Three nuclear medicine consultants reviewed the studies to determine the presence and identify the uptake patterns of HFI. Quantitative evaluation was performed on PET images using the total number of counts over the frontal bone and the ratio of counts between the frontal bone and iliac crest.

RESULTS

A total of 105 out of 249 cases were included in this study. Among these scans, there were 67 positive HFI in [ 18 F]NaF PET scans representing 64% of the studied population. As for the [ 18 F]NaF PET uptake pattern, there were 53 with uniformly diffused and 14 with heterogeneous uptake pattern. There were 17 out of 67 with positive HFI in [ 18 F]NaF PET scans but negative CT scans.

CONCLUSION

HFI is a common finding on [ 18 F]NaF PET in obese patients and is probably underdiagnosed. HFI may present with a heterogeneous and diffuse pattern of uptake on [ 18 F]NaF PET. The proposed quantitative analysis using the count ratios is in agreement with the visual evaluation of [ 18 F]NaF PET images regardless of the CT findings. Awareness of this condition and its scintigraphic patterns is warranted since it can have clinical significance and may mimic other pathologies including metastasis in cancer patients.

The Case for Bisphosphonate Use in Astronauts Flying Long-Duration Missions

Changes in the structure of bone can occur in space as an adaptive response to microgravity and on Earth due to the adaptive effects to exercise, to the aging of bone cells, or to prolonged disuse. Knowledge of cell-mediated bone remodeling on Earth informs our understanding of bone tissue changes in space and whether these skeletal changes might increase the risk for fractures or premature osteoporosis in astronauts. Comparisons of skeletal health between astronauts and aging humans, however, may be both informative and misleading. Astronauts are screened for a high level of physical fitness and health, are launched with high bone mineral densities, and perform exercise daily in space to combat skeletal atrophy as an adaptive response to reduced weight-bearing function, while the elderly display cellular and tissue pathology as a response to senescence and disuse. Current clinical testing for age-related bone change, applied to astronauts, may not be sufficient for fully understanding risks associated with rare and uniquely induced bone changes. This review aims to (i) highlight cellular analogies between spaceflight-induced and age-related bone loss, which could aid in predicting fractures, (ii) discuss why overreliance on terrestrial clinical approaches may miss potentially irreversible disruptions in trabecular bone microarchitecture induced by spaceflight, and (iii) detail how the cellular effects of the bisphosphonate class of drugs offer a prophylactic countermeasure for suppressing the elevated bone resorption characteristically observed during long-duration spaceflights. Thus the use of the bisphosphonate will help protect the bone from structural changes while in microgravity either along with exercise or alone when exercise is not performed, e.g. after an injury or illness.

A Life-Stage Approach to Precision Nutrition: A Narrative Review

The concept of precision nutrition highlights the customization of nutrition to specific needs, emphasizing that a one-size-fits-all approach is not sufficient for either optimal nutrition or optimal health. Precision nutrition encompasses a range of factors, from broad strata of age and sex categories to personal characteristics such as lifestyle to an individual's unique genotype. This breadth of scope requires us to consider how precision nutrition can be implemented in an inclusive and appropriate way for individuals and groups within real-life populations. In this narrative review, we explore the potential of precision nutrition through a life-stage approach that emphasizes age- and gender-specific nutritional needs as these change across the lifespan. Focusing on adult life stages, we delineated trends in age-related conditions and health needs among Korean adults based on national-level survey data (KNHANES 2019-2021). We also reviewed the intake of nutrients associated with these health needs to better understand how life-stage guided approaches to nutrition and supplementation could support optimal health. Looking beyond preventing deficiency or disease, we discuss how tailored supplementation of essential vitamins, minerals, and certain bioactive substances could promote healthy functioning. Finally, we discuss the complexities and challenges of developing multivitamin/multimineral supplements (MVMS) to support life-stage appropriate nutrition while maximizing adherence. Future prospects include leveraging advancements in intelligent technologies and dietary assessments for tracking nutrient intake and health indicators and using these to optimize MVMS formulations in ways that are sensitive to a person's needs and priorities/preferences at different life stages. By adopting a life-stage guided approach to nutrition, we can better support health and well-being across the lifespan.

Irisin as an agent for protecting against osteoporosis: A review of the current mechanisms and pathways

BACKGROUND

Osteoporosis is recognized as a skeletal disorder characterized by diminished bone tissue quality and density. Regular physical exercise is widely acknowledged to preserve and enhance bone health, but the detailed molecular mechanisms involved remain unclear. Irisin, a factor derived from muscle during exercise, influences bone and muscle. Since its discovery in 2012, irisin has been found to promote bone growth and reduce bone resorption, establishing a tangible link between muscle exertion and bone health. Consequently, the mechanism by which irisin prevents osteoporosis have attracted significant scientific interest.

AIM OF THE REVIEW

This study aims to elucidate the multifaceted relationship between exercise, irisin, and bone health. Focusing on irisin, a muscle-derived factor released during exercise, we seek to understand its role in promoting bone growth and inhibiting resorption. Through a review of current research article on irisin in osteoporosis, Our review provides a deep dive into existing research on influence of irisin in osteoporosis, exploring its interaction with pivotal signaling pathways and its impact on various cell death mechanisms and inflammation. We aim to uncover the molecular underpinnings of how irisin, secreted during exercise, can serve as a therapeutic strategy for osteoporosis.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

Irisin, secreted during exercise, plays a vital role in bridging muscle function to bone health. It not only promotes bone growth but also inhibits bone resorption. Specifically, Irisin fosters osteoblast proliferation, differentiation, and mineralization predominantly through the ERK, p38, and AMPK signaling pathways. Concurrently, it regulates osteoclast differentiation and maturation via the JNK, Wnt/β-catenin and RANKL/RANK/OPG signaling pathways. This review further delves into the profound significance of irisin in osteoporosis and its involvement in diverse cellular death mechanisms, including apoptosis, autophagy, ferroptosis, and pyroptosis.

Denosumab Prevents Bone Loss and Microarchitectural Deterioration in Premenopausal Women With Breast Cancer Receiving Estradiol Suppression Therapy: A Randomized Controlled Trial

PURPOSE

Suppression of ovarian function and aromatase inhibition (AI) increases disease-free survival in premenopausal women with estrogen receptor (ER)-positive early-stage breast cancer but accelerates bone loss. We therefore hypothesized that suppressing bone remodeling using denosumab (DMAB) would prevent bone loss in these women.

METHODS

In a 12-month double-blind randomized trial, 68 women with ER-positive early-stage breast cancer commencing ovarian function suppression and AI were randomly assigned to 60 mg DMAB (n = 34) or placebo (PBO; n = 34) once every 6 months (at 0 and 6 months). Volumetric bone mineral density (BMD), microarchitecture, and estimated bone strength of the distal tibia and distal radius were measured using high-resolution peripheral quantitative computed tomography, and spine and hip BMD were measured using dual-energy X-ray absorptiometry at 0, 6, and 12 months. The primary end point and treatment effect was the mean adjusted between group difference (MAD; [95% CI]) in distal tibial total volumetric BMD over 12 months, with a single P value tested over all time points. The study is registered with the Australian New Zealand Clinical Trials Registry (anzctr.org.au; identifier: ACTRN12616001051437).

RESULTS

Intention-to-treat analysis included all 68 randomly assigned women. Over 12 months, compared with PBO, DMAB prevented the decrease in distal tibial total BMD (MAD, 20.8 mg HA/cm3 [95% CI, 17.3 to 24.2]), cortical BMD (42.9 mg HA/cm3 [95% CI, 32.1 to 53.9]), trabecular BMD (3.32 mg HA/cm3 [95% CI, 1.45 to 5.20], P = .004), estimated stiffness (11.6 kN/m [95% CI, 7.6 to 15.6]), and failure load (563 N [95% CI, 388 to 736]). Findings were similar at the distal radius. Decreases in BMD at the lumbar spine (MAD, 0.13 g/cm2 [95% CI, 0.11 to 0.15]), total hip (0.08 g/cm2 [95% CI, 0.07 to 0.09], and femoral neck (0.06 g/cm2 [95% CI, 0.05 to 0.07]) were also prevented. All P < .001 unless otherwise noted.

CONCLUSION

Treatment with DMAB at commencement of estradiol suppression therapy preserves BMD, bone microarchitecture, and estimated strength, and is likely to increase fracture-free survival.

The Effectiveness of a Lactobacilli-Based Probiotic Food Supplement on Bone Mineral Density and Bone Metabolism in Australian Early Postmenopausal Women: Protocol for a Double-Blind Randomized Placebo-Controlled Trial

Osteoporosis affects one in three women over the age of 50 and results in fragility fractures. Oestrogen deficiency during and after menopause exacerbates bone loss, accounting for higher prevalence of fragility fractures in women. The gut microbiota (GM) has been proposed as a key regulator of bone health, as it performs vital functions such as immune regulation and biosynthesis of vitamins. Therefore, GM modulation via probiotic supplementation has been proposed as a target for potential therapeutic intervention to reduce bone loss. While promising results have been observed in mouse model studies, translation into human trials is limited. Here, we present the study protocol for a double-blind randomized controlled trial that aims to examine the effectiveness of three lactobacilli strains on volumetric bone mineral density (vBMD), trabecular, and cortical microstructure, as measured using High Resolution peripheral Quantitative Computed Tomography (HR-pQCT). The trial will randomize 124 healthy early postmenopausal women (up to 8 years from menopause) to receive either probiotic or placebo administered once daily for 12 months. Secondary outcomes will investigate the probiotics' effects on areal BMD and specific mechanistic biomarkers, including bone metabolism and inflammatory markers. The trial is registered with Australian New Zealand Clinical Trials Registry (ACTRN12621000810819).

Hormonal contraceptive use is associated with altered bone structural and metabolic responses to military training in women: An observational cohort study

Military training increases tibial density and size. Female sex hormones may influence the adaption of bone to loading, but it is unknown if women using different hormonal contraceptives adapt similarly to military training. One hundred and sixteen women (57 women not using hormonal contraceptives [non-users], 38 combined oral contraceptive pill [COCP] users, 21 depot medroxyprogesterone acetate [DMPA] users) completed this study. Tibial volumetric bone mineral density (vBMD) and geometry were measured by peripheral quantitative computed tomography (4 %, 14 %, 38 %, and 66 % sites) at the start (week 1) and end (week 14) of British Army basic training. Circulating markers of bone and calcium metabolism were measured at weeks 1, 2, 4, 6, 10, and 14. Training increased trabecular vBMD at the 4 % site, periosteal perimeter at the 14 % and 66 % sites, and total area, cortical area, cortical thickness, and bone strength at all sites (0.1 to 1.6 %, p ≤ 0.009), with no differences between hormonal contraceptive groups (p ≥ 0.127). Trabecular vBMD increased at the 14 % site in non-users (0.8 %, p = 0.005), but not in COCP or DMPA users (p ≥ 0.205). Periosteal perimeter increased at the 38 % site in COCP (0.4 %, p < 0.001) and DMPA (0.5 %, p < 0.001) users, but not in non-users (p = 0.058). Training had no effect on periosteal perimeter at the 4 % site or cortical vBMD or endosteal perimeter at any site (p ≥ 0.168). βCTX decreased and PINP increased during training with no difference between hormonal contraceptive groups. Training increased iPTH in non-users, but not COCP or DMPA users. Hormonal contraceptives may exert site-specific effects on the mechanobiology of bone, with higher endogenous oestradiol promoting trabecularisation and inhibiting periosteal expansion in non-users compared with hormonal contraceptive users.

Characteristics of bone mineral density in patients with functional hypothalamic amenorrhoea and its association with reproductive hormones and body composition

OBJECTIVE

Bone mineral density (BMD) is typically reduced in patients with female athlete triad (FAT) and anorexia nervosa (AN). However, bone health in most patients with functional hypothalamic amenorrhoea (FHA), who may not suffer from severe energy deficiency, has not received adequate attention in clinical practice. This study aimed to investigate BMD and its association with clinical and endocrine features in individuals with FHA and to provide clinical evidence for improving bone loss and preventing osteoporosis in FHA.

DESIGN

To assess the bone status of patients with FHA and investigate its association with various clinical and endocrinological characteristics.

PATIENTS

We retrospectively analysed 80 patients with FHA who attended the Obstetrics and Gynecology Hospital of Fudan University from January 2022 to March 2023.

MEASUREMENTS

The levels of reproductive hormones, including luteinising hormone (LH), follicle-stimulating hormone, oestradiol (E2 ) and total testosterone (TT), were examined at the time of initial diagnosis, and a body composition analyser was used to measure body fat percentage (BF%), lean body mass (LBM) and segmental muscle/fat. Dual-emission X-ray absorptiometry was used to measure lumbar spine BMD and femoral neck BMD in patients with FHA, and the Z score was calculated.

RESULTS

The study cohort consisted of 80 female patients with FHA. The average age of the patients was 24.64 ± 6.02 years, and their body mass index (BMI) was 19.47 ± 2.86 kg/m2 . The duration of weight loss was 12 (6, 24) months, while the duration of oligo/amenorrhoea was 12 (4.5, 24) months. The mean degree of weight loss was 18.39 ± 9.53%. Low BMD were present in 15% of patients with FHA at the lumbar spine and/or femoral neck; 12.5% and 10% had low bone mass at the lumbar spine and femoral neck, respectively. The low bone mass group experienced a longer period of weight loss than the normal group [24 (16.5, 60) vs. 12 (4.5, 24) months, p = .037]. In addition, the abnormal group had a lower BMR (basal metabolic rate, BMR) [1158 ± 85 vs. 1231 ± 91 kcal/day, p = .011] and lower bone mineral content [2.15 ± 0.26 vs. 2.43 ± 0.31 kg, p = .009] than the normal group. Both LBMD and femoral neck BMD (Fn BMD) were positively correlated with BMI, BF%, LBM, and regional muscle/fat mass (all p < .05). There was also a positive correlation between LBMD and basal LH levels (p = .009) and waist-to-hip ratio (p = .034), whereas Fn BMD was positively correlated with TT levels (p = .029). Multiple linear regression analysis showed that LBM was positively associated with LBMD (β = .007, 95% confidence interval [CI] = 0.004-0.009, p < .001), while trunk muscle mass was positively associated with Fn BMD (β = .046, 95% CI = 0.013-0.080, p = .008).

CONCLUSION

Fifteen percent of the patients with FHA exhibited low bone mass, a condition associated with prolonged weight loss. The basal LH and TT levels showed positive correlations with LBMD and Fn BMD, respectively. Meanwhile, BMR levels, BMI, BF%, and muscle mass were all positively correlated with LBMD and Fn BMD. Clinically, we should be attentive to suboptimal bone health in patients with FHA and take early screening, diagnosis and intervention measures, especially appropriate muscle mass gain, to prevent the onset of osteoporosis and fragility fractures in the long term.

Using machine learning techniques to predict the risk of osteoporosis based on nationwide chronic disease data

Osteoporosis is a major public health concern that significantly increases the risk of fractures. The aim of this study was to develop a Machine Learning based predictive model to screen individuals at high risk of osteoporosis based on chronic disease data, thus facilitating early detection and personalized management. A total of 10,000 complete patient records of primary healthcare data in the German Disease Analyzer database (IMS HEALTH) were included, of which 1293 diagnosed with osteoporosis and 8707 without the condition. The demographic characteristics and chronic disease data, including age, gender, lipid disorder, cancer, COPD, hypertension, heart failure, CHD, diabetes, chronic kidney disease, and stroke were collected from electronic health records. Ten different machine learning algorithms were employed to construct the predictive mode. The performance of the model was further validated and the relative importance of features in the model was analyzed. Out of the ten machine learning algorithms, the Stacker model based on Logistic Regression, AdaBoost Classifier, and Gradient Boosting Classifier demonstrated superior performance. The Stacker model demonstrated excellent performance through ten-fold cross-validation on the training set and ROC curve analysis on the test set. The confusion matrix, lift curve and calibration curves indicated that the Stacker model had optimal clinical utility. Further analysis on feature importance highlighted age, gender, lipid metabolism disorders, cancer, and COPD as the top five influential variables. In this study, a predictive model for osteoporosis based on chronic disease data was developed using machine learning. The model shows great potential in early detection and risk stratification of osteoporosis, ultimately facilitating personalized prevention and management strategies.

The detection of Gper1 as an important gene promoting jawbone regeneration in the context of estrogen deficiency

Numerous studies have demonstrated that estrogen deficiency inhibit the proliferation and differentiation of pre-osteoblasts in skeleton by affecting osteogenic signaling, lead to decreased bone mass and impaired regeneration. To explore the mechanisms maintaining bone regeneration under estrogen deficiency, we randomly selected 1102 clinical cases, in which female patients aged between 18 and 75 have underwent tooth extraction in Stomatological Hospital of Tongji University, there is little difference in the healing effect of extraction defects, suggesting that to some extent, the regeneration of jawbone is insensitive to the decreased estrogen level. To illuminate the mechanisms promoting jawbone regeneration under estrogen deficiency, a tooth extraction defect model was established in the maxilla of female rats who underwent ovariectomy (OVX) or sham surgery, and jawbone marrow stromal cells (BMSCs) were isolated for single-cell sequencing. Further quantitative PCR, RNA interference, alizarin red staining, immunohistochemistry and western blotting experiments demonstrated that in the context of ovariectomy, maxillary defects promoted G protein-coupled estrogen receptor 1 (Gper1) expression, stimulate downstream cAMP/PKA/pCREB signaling, and facilitate cell proliferation, and thus provided sufficient progenitors for osteogenesis and enhanced the regeneration capacity of the jawbone. Correspondingly, the heterozygous deletion of the Gper1 gene attenuated the phosphorylation of CREB, led to decreased cell proliferation, and impaired the restoration of maxillary defects. This study demonstrates the importance of Gper1 in maintaining jawbone regeneration, especially in the context of estrogen deficiency.

PMAIP1, a novel diagnostic and potential therapeutic biomarker in osteoporosis

BACKGROUND

Osteoporosis is a common endocrine metabolic bone disease, which may lead to severe consequences. However, the unknown molecular mechanism of osteoporosis, the observable side effects of present treatments and the inability to fundamentally improve bone metabolism seriously restrict the impact of prevention and treatment. The study aims to identify potential biomarkers from osteoclast progenitors, specifically peripheral blood monocytes on predicting the osteoporotic phenotype.

METHODS

Datasets were obtained from Gene Expression Omnibus (GEO). Based on the differentially expressed genes (DEGs) and GSEA results, GO and KEGG analyses were performed using the DAVID database and Metascape database. PPI network, TF network, drug-gene interaction network, and ceRNA network were established to determine the hub genes. Its osteogenesis, migration, and proliferation abilities in bone marrow mesenchymal stem cells (BMSCs) were validated through RT-qPCR, WB, ALP staining, VK staining, wound healing assay, transwell assay, and CCK-8 assay.

RESULTS

A total of 63 significant DEGs were screened. Functional and pathway enrichment analysis discovered that the functions of the significant DEGs (SDEGs) are mainly related to immunity and metal ions. A comprehensive evaluation of all the network analyses, PMAIP1 was defined as osteoporosis's core gene. This conclusion was further confirmed in clinical cohort data. A series of experiments demonstrated that the PMAIP1 gene can promote the osteogenesis, migration and proliferation of BMSC cells.

CONCLUSIONS

All of these outcomes showed a new theoretical basis for further research in the treatment of osteoporosis, and PMAIP1 was identified as a potential biomarker for osteoporosis diagnosis and treatment.

Calcium Deficiency Decreases Bone Mass without Affecting Adiposity in Ovariectomized Rats Fed a High-Fat Diet

Obesity induced by a high-fat (HF) diet increases bone resorption and/or decreases bone formation, resulting in reduced bone mass and strength in various animal models. Studies showed that Ca intake is a modifiable factor for osteoporosis and obesity. This study investigated whether Ca deficiency affects bone structure and adiposity in ovariectomized (OVX) rats fed a HF diet. We hypothesized that Ca deficiency further decreases bone mass and increases fat mass in HF-fed OVX rats. Forty-seven OVX at 6-month-old were randomly assigned to four groups in a 2 × 2 factorial design: normal-fat (NF, 10% fat as energy) or HF (45% fat as energy) diet with either low Ca (LC, 1 g/4057 kcal) or normal Ca (NC, 6 g/4057 kcal). In addition, 12 sham-operated rats at 6 months old were fed a NFNC diet as a control for the OVX procedure. Rats were fed the respective diet for 4 months. Dietary Ca content did not affect body weight, fat mass, lean mass, food intake, energy intake, and serum cytokines. Compared to NC, LC resulted in lower tibial bone volume/total volume (BV/TV, p < 0.01), connectivity density (p < 0.01), trabecular number (Tb.N, p = 0.01), bone mineral density (BMD, p < 0.01), and femur weight (p < 0.01), femur content of Ca (p < 0.01), Cu (p = 0.03), Zn (p < 0.01), and greater trabecular separation (Tb.Sp, p < 0.01) at proximal tibia indicating bone structure deterioration. Compared to rats on the NF diet, animals fed the HF had lower BV/TV (p = 0.03) and Tb.N (p < 0.01) with greater body weight (p < 0.01), fat mass (p < 0.01), Tb.Sp (p = 0.01), the content of Ca, Cu, and Zn in the femur, and serum leptin (p < 0.01). There were no significant interactions between Ca and fat for body composition and bone structural parameters. Compared to Sham, OVX resulted in greater body weight and fat mass. The trabecular bone structure of the tibia, but not the cortical bone, was significantly impaired by the OVX procedure. These data indicate that inadequate Ca intake and a high-fat diet have independent negative effects on bone structure and that Ca deficiency does not affect adiposity in OVX rats.

Comparing a common clavicle maturation-based age estimation method to ordinary regression analyses with quadratic and sex-specific interaction terms in adolescents

Established methods of age estimation are based on correlating defined maturation stages of bony structures with tables representing the observed range of biological ages in the majority of cases. In this retrospective monocentric study in southwestern Germany, common age estimation methodology was assessed in n = 198 subjects at the age of 25 or younger by analyzing the influence of age, quadratic age, biological sex and age-sex interaction on the ossification stages of the medial epiphysis fugue. Three readers (ICC ≥ 0.81 for left/right side) evaluated routine care computed tomography images of the clavicle with a slice thickness of 1 mm. By using least square regression analyses, to determine the real biological age a quadratic function was determined corrected for the age estimated by established methods and sex (R2 = 0.6 each side), reducing the mean absolute error and root mean squared error in the age estimation of women (2.57 and 3.19) and men (2.57 and 3.47) to 1.54 and 1.82 for women, and 1.54 and 2.25 for men. In women, the medial clavicle epiphysis seem to fuse faster, which was particularly observable from approximately 18 years of age. Before that age, the estimation method was relatively close to the ideal correlation between assessed and real age. To conclude, the presented new method enables more precise age estimation in individuals and facilitates the determination and quantification of additional variables, quantifying their influence on the maturation of the medial clavicle epiphysis based on the established ossification stages.

Linoleic acid blunts early osteoblast differentiation and impairs oxidative phosphorylation in vitro

BACKGROUND

Linoleic acid (LNA), an essential polyunsaturated fatty acid (PUFA), plays a crucial role in cellular functions. However, excessive intake of LNA, characteristic of Western diets, can have detrimental effects on cells and organs. Human observational studies have shown an inverse relationship between plasma LNA concentrations and bone mineral density. The mechanism by which LNA impairs the skeleton is unclear, and there is a paucity of research on the effects of LNA on bone-forming osteoblasts.

METHODS

The effect of LNA on osteoblast differentiation, cellular bioenergetics, and production of oxidized PUFA metabolites in vitro, was studied using primary mouse bone marrow stromal cells (BMSC) and MC3T3-E1 osteoblast precursors.

RESULTS

LNA treatment decreased alkaline phosphatase activity, an early marker of osteoblast differentiation, but had no effect on committed osteoblasts or on mineralization by differentiated osteoblasts. LNA suppressed osteoblast commitment by blunting the expression of Runx2 and Osterix, key transcription factors involved in osteoblast differentiation, and other key osteoblast-related factors involved in bone formation. LNA treatment was associated with increased production of oxidized LNA- and arachidonic acid-derived metabolites and blunted oxidative phosphorylation, resulting in decreased ATP production.

CONCLUSION

Our results show that LNA inhibited early differentiation of osteoblasts and this inhibitory effect was associated with increased production of oxidized PUFA metabolites that likely impaired energy production via oxidative phosphorylation.

Controversial causal association between IGF family members and osteoporosis: a Mendelian randomization study between UK and FinnGen biobanks

Objectives

Osteoporosis, a prevalent skeletal disorder characterized by reduced bone strength, is closely linked to the IGF system, crucial for skeletal metabolism. However, the precise nature of this relationship remains elusive. In this study, we employed Mendelian randomization (MR) to unravel the associations between genetically predicted serum IGF system member levels and osteoporosis.

Methods

A two-sample MR approach was employed to investigate these causal associations based on two individual datasets. Predictions of 14 serum levels of IGF system members were made using 11,036,163 relevant Single Nucleotide Polymorphisms (SNPs) within a cohort of 4,301 individuals of European descent. Genetic association estimates for osteoporosis were derived from two publicly available GWAS consortia: the Finnish consortium from the FinnGen biobank, comprising 212,778 individuals of Finnish descent (3,203 cases and 209,575 controls), and the UK consortium from the UK Biobank, including 337,159 individuals of European descent (5,266 cases and 331,893 controls).

Results

According to the UK dataset, IGF-1 levels were associated with a reduced risk of osteoporosis, as indicated by the weighted median method (Odds Ratio [OR] = 0.998, 95% CI = 0.997-1.000, P = 0.032). Additionally, higher levels of IGFBP-3 were linked to a decreased risk of osteoporosis using the Inverse-Variance Weighted (IVW) method (OR = 0.999, 95% CI = 0.998-1.000, P = 0.019), and CTGF levels exhibited a negative association with osteoporosis, as determined by the weighted median method (OR = 0.998, 95% CI = 0.996-0.999, P = 0.004). In the FinnGen dataset, IGF-1 and IGFBP-3 were not identified to be associated with osteoporosis. While, IGF-LR1 levels displayed a negative association with osteoporosis, according to the MR-Egger method (OR = 0.886, 95% CI = 0.795-0.987, P = 0.036), while CYR61 was linked to an increased risk of osteoporosis based on both the weighted median and IVW methods (OR = 1.154, 95% CI = 1.009-1.319, P = 0.037, and OR = 1.115, 95% CI = 1.022-1.215, P = 0.014, respectively).

Conclusion

This study provides compelling evidence that certain IGF family members play a role in the pathogenesis of osteoporosis between different datasets, indicating population specific causal effects between IGF family and osteoporosis. Although the results from both datasets demonstrated that IGF family involved in the pathogenesis of osteoporosis, but the responding key molecules might be various among different population. Subsequent research is warranted to evaluate the potential of these biomarkers as targets for osteoporosis prevention and treatment in specific population.

Effects of Hormone Replacement Therapy on Bone Mineral Density in Korean Adults With Turner Syndrome

BACKGROUND

Turner syndrome (TS) is a common chromosomal abnormality, which is caused by loss of all or part of one X chromosome. Hormone replacement therapy in TS is important in terms of puberty, growth and prevention of osteoporosis however, such a study has never been conducted in Korea. Therefore, the purpose of our study was to determine relationship between the starting age, duration of estrogen replacement therapy (ERT) in TS and develop a hormone replacement protocol suitable for the situation in Korea.

METHODS

This is retrospective study analyzed the medical records in TS patients treated at the Severance hospital, Yonsei University College of Medicine, Seoul, Korea from 1997 to 2019. Total of 188 subjects who had received a bone density test at least once were included in the study. Korean National Health and Nutrition Examination Survey (KNHANES) was used for achieving bone mineral density (BMD) of normal control group. Student's t-test, Mann-Whitney U test, ANOVA and correlation analysis were performed using SPSS 18.0.

RESULTS

Each BMD measurement was significantly lower in women with TS than in healthy Korean women. Early start and longer duration of ERT is associated with higher lumbar spine BMD but not femur neck BMD. Femur neck BMD, but not lumbar spine BMD was significantly higher in women with mosaicism than 45XO group.

CONCLUSION

Early onset and appropriate duration of hormone replacement therapy is important for increasing bone mineral density in patients with Turner syndrome. Also, ERT affects differently to TS patients according to mosaicism.

Crosstalk Between the Neuroendocrine System and Bone Homeostasis

The homeostasis of bone microenvironment is the foundation of bone health and comprises 2 concerted events: bone formation by osteoblasts and bone resorption by osteoclasts. In the early 21st century, leptin, an adipocytes-derived hormone, was found to affect bone homeostasis through hypothalamic relay and the sympathetic nervous system, involving neurotransmitters like serotonin and norepinephrine. This discovery has provided a new perspective regarding the synergistic effects of endocrine and nervous systems on skeletal homeostasis. Since then, more studies have been conducted, gradually uncovering the complex neuroendocrine regulation underlying bone homeostasis. Intriguingly, bone is also considered as an endocrine organ that can produce regulatory factors that in turn exert effects on neuroendocrine activities. After decades of exploration into bone regulation mechanisms, separate bioactive factors have been extensively investigated, whereas few studies have systematically shown a global view of bone homeostasis regulation. Therefore, we summarized the previously studied regulatory patterns from the nervous system and endocrine system to bone. This review will provide readers with a panoramic view of the intimate relationship between the neuroendocrine system and bone, compensating for the current understanding of the regulation patterns of bone homeostasis, and probably developing new therapeutic strategies for its related disorders.

Daily supplement of sesame oil prevents postmenopausal osteoporosis via maintaining serum estrogen and aromatase levels in rats

Estrogen deficiency is one of the main causes of postmenopausal osteoporosis in elderly women. Hormone replacement therapy has been employed to manage postmenopausal osteoporosis; however, it has raised concerns related to heart attacks and breast cancer. Sesame oil has been reported to affect sex hormone status. The aim of the present study is to evaluate the effect of sesame oil supplement on postmenopausal osteoporosis in rats. We used female Sprague Dawley rats that underwent bilaterally ovariectomy (OVX) as an experimental postmenopausal osteoporosis animal model. These rats were orally administrated sesame oil (0.25 or 0.5 mL/kg/day) for four months as the therapeutic group. We assessed bone mineral density (BMD) and the levels of osteocalcin, procollagen-I C-terminal propeptide (PICP), collagen cross-linked N-telopeptide (NTx), estradiol, and aromatase in the sera. The daily supplementation of sesame oil significantly increased BMD, serum osteocalcin levels, and trabecular areas in the OVX-treated rats. Sesame oil also elevated serum PICP levels and decreased NTx levels in these rats. Furthermore, sesame oil effectively maintained serum estradiol and aromatase levels in the OVX-induced osteoporosis rats. In conclusion, daily supplementation of sesame oil prevents postmenopausal osteoporosis by maintaining serum estrogen and aromatase levels, while also modulating the imbalance between bone formation and resorption in osteoporosis rats.

New Emerging Aspect of Herbal Extracts for the Treatment of Osteoporosis: Overview

As the global population ages, osteoporosis is becoming a more common silent disease. Osteoporosis is characterized by decreased bone quality and strength, which increases the risk of fragility fractures in the elderly. According to estimates, 50% of women eventually suffer from an osteoporotic fracture. Due to increasing disability, more frequent hospital hospitalizations, and most critically, fragility fractures have been linked to a reduced quality of life. Osteoporotic fractures have been linked to an increased mortality risk; and must be considered in awareness as a serious health concern. There are anti-osteoporotic medications available that improve bone quality. Considering the availability of various treatment options, still there are a lot of underserved needs in the treatment of fractures and osteoporosis. For example, the application of natural products and herbal resources for fracture healing, because of the androgen-like and antioxidant characteristics of the plants, they can play a crucial for accelerating the repair of bone fractures. In this article, we'll discuss the herbal remedies that are essential for treating osteoporosis (bone disease).

The roles of sex hormones in the pathophysiology of age-related sarcopenia and frailty

Background

Sarcopenia is an age-related condition characterized by a progressive and systemic decline in skeletal muscle mass, quality, and strength. The incidence of sarcopenia contains sex-specific aspects, indicating the contribution of sex hormones to its pathophysiology. This review focuses on changing trends in sarcopenia, discusses alterations in definitions and diagnostic criteria, and emphasizes the association between sarcopenia and sex hormones.

Methods

A literature search was performed on PubMed for related articles published between 1997 and December 2023 using appropriate keywords.

Main Findings Results

Advances in research have emphasized the significance of muscle quality and strength over muscle mass, resulting in new diagnostic criteria for sarcopenia. Androgens demonstrated anabolic effects on skeletal muscles and played a significant role in the pathophysiology of sarcopenia. In clinical settings, androgen replacement therapy has exhibited certain positive outcomes for treating sarcopenia, despite concerns about potential side effects. Conversely, estrogen is involved in skeletal muscle maintenance, but the detailed mechanisms remain unclear. Moreover, results regarding the clinical application of estrogen replacement therapy for treating sarcopenia remained inconsistent.

Conclusion

The elucidation of molecular mechanisms that involve sex hormones is eagerly awaited for novel therapeutic interventions for sarcopenia.

Jiangu granules ameliorate postmenopausal osteoporosis via rectifying bone homeostasis imbalance: A network pharmacology analysis based on multi-omics validation

BACKGROUND

Postmenopausal osteoporosis (PMOP) is a series of reactions to bone homeostasis dysregulation mediated by estrogen deficiency in elderly women. Jiangu granules, a traditional Chinese medicine formula, has been proven as an effective treatment approach for PMOP, which still needs more research iin its complex regulatory mechanisms.

PURPOSE

Our study aimed to identify the putative targets and regulatory mechanisms of Jiangu granules in PMOP treating.

METHODS

We utilized the NHANES database to compare the clinical information of normal population and PMOP patients. Associated with transcriptomics and proteomic data, we identified the PMOP-related genes, and further studied them with bioinformatic methods including and prognosis model. Network pharmacology was applied for confirming the action targets of Jiangu granules in PMOP. We verified the safety and effectiveness in PMOP treatments of Jiangu granules, and also demonstrated our hypothesis in rats.

RESULTS

We discovered that the PMOP patients had higher monocytes than the normal women. Moreover, the transcriptomics and proteomic analysis suggested that the dysregulation of PMOP-related genes expression was associated with monocytes, and the Notch pathway were the critical targets representing bone homeostasis imbalance highly involved in the occurrence of PMOP. We also ascertained network pharmacology results further revealing that Jiangu granules might treat PMOP via recovering the bone homeostasis imbalance identified above. In vivo experiments, we confirmed the high efficacy which mainly resulted from function in mitigating the imbalance in bone homeostasis by recovering the normal expression of PMOP-related genes associated with monocytes, Notch, and steroid pathway in the rat models.

CONCLUSION

Our finding underscored the clinical potential of Jiangu granules in treating PMOP, and enriched the comprehension of the related pathogenic and therapeutic mechanisms.

Association between monocyte to high-density lipoprotein-cholesterol ratio and osteoporosis: An analysis of the National Health and Nutrition Examination Survey 2013-2014

The monocyte to high-density lipoprotein-cholesterol (HDL-C) ratio (monocyte-to-HDL-C ratio) was proposed as a marker of atherosclerosis. Osteoporosis and atherosclerosis share common risk factors and pathophysiological mechanisms. This study aimed to assess the relationship between monocyte-to-HDL-C ratio and osteoporosis. Participants aged ≥50 years with complete bone mineral density (BMD), monocyte, and HDL-C examination data from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were included. Descriptive analysis was performed separately according to males and females. Weight linear regression and weight logistic regression analyses were used to analyze the association between the monocyte-to-HDL-C ratio and BMD and osteopenia and osteoporosis and vertebral fracture. A total of 1804 participants were included. Among the participants with osteopenia, 398 (48.31%) were males and 466 (51.91%) were females. Among those with osteoporosis, 38 (2.77%) were males and 95 (9.50%) were females. In females, monocyte-to-HDL-C ratio was negatively associated with femoral neck BMD (regression coefficient (β) = -0.18; 95% confidence interval (CI): (-0.29, -0.07)) and high monocyte-to-HDL-C ratio was associated with higher odds of osteopenia (odds ratio (OR) = 1.22; 95% CI: (1.01, 1.47)) and osteoporosis (OR = 1.68; 95% CI: (1.13, 2.49)) after adjusting for confounders. In males, only monocyte-to-HDL-C ratio >0.35 was observed to be associated with higher odds of osteoporosis (OR = 1.96; 95% CI: (1.02, 3.79)). Stratified analyses showed that similar results were also found in different populations. This study showed that the monocyte-to-HDL-C ratio was negatively associated with BMD and the risk of osteopenia and osteoporosis in females. The monocyte-to-HDL-C ratio may be a new marker of osteoporosis or osteopenia.

Bone mineral density fall during aromatase inhibitor treatment may predict lower breast cancer recurrence

PURPOSE

Aromatase inhibitors (AIs) are associated with reduction in bone mineral density (BMD). The use of bone strengthening agents zoledronic acid and denosumab are associated with improved breast cancer outcomes for post-menopausal patients treated with AIs. This study investigates whether change in BMD with AI therapy is associated with breast cancer recurrence.

METHODS

A cohort of patients treated at a single institution diagnosed with hormone receptor-positive breast cancer with baseline BMD and subsequent BMD test while receiving adjuvant aromatase inhibitor therapy were studied. Demographic, treatment and outcome data was obtained. Simple and multiple linear regression analysis was performed to investigate predictors of annual percent BMD change at the LS and hip. Univariate and multivariate Cox proportional hazards modelling were undertaken to investigate predictors of breast cancer recurrence.

RESULTS

353 patients eligible patients were identified. In multivariate analysis of lumbar spine BMD change, the difference between those in quartile 1, which showed the greatest reduction in BMD, and quartile 3, with substantially less reduction, was significant (HR = 3.02, 95% CI 1.15-7.90 p = 0.025). Hip BMD reduction was also not significantly associated with breast cancer recurrence. The two quartiles with the least reduction in hip BMD showing a non-significant reduced risk of recurrence relative to the quartile with the greatest (p = 0.10).

CONCLUSIONS

The findings suggest an association may exist between lumbar spine BMD change and breast cancer recurrence for patients treated with adjuvant AI. Further research is required to determine whether BMD change can be utilised as a biomarker.

Estrogen receptor-mediated health benefits of phytochemicals: a review

Estrogen receptors (ERs) are transcription factors with two subtypes: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which are essential for the maintenance of human health and play a regulatory role in common diseases such as breast cancer, osteoporosis, neurodegenerative disorders, liver injuries and lung cancers. A number of phytochemicals extracted from various fruits and vegetables have been demonstrated to exhibit estrogenic effects and are termed phytoestrogens. As modulators of ERs, phytoestrogens can be involved in the prevention and treatment of multiple diseases as complementary or alternative therapeutic agents and have a variety of health benefits for humans. This article reviews the health benefits of phytoestrogens in clinical and epidemiologic studies for several diseases and also provides a detailed description of the molecular mechanisms of their action. A brief comparison of the advantages and disadvantages of natural phytochemicals compared to synthetic drugs is also presented. The role of phytoestrogens in the treatment of diseases and human health requires further research to fully realize their therapeutic potential.

The potential role of osteoporosis in unspecific [18F]PSMA-1007 bone uptake

AIM

Unspecific bone uptake is one of the main limitations of PET imaging with some PSMA-targeting radiopharmaceuticals, especially with [18F]PSMA-1007. We explored the potential association between osteoporosis and the occurrence of unspecific [18F]PSMA-1007 bone uptake investigating markers which might correlate with bone mineral density.

MATERIALS AND METHODS

We retrospectively analyzed treatment-naïve patients with a confirmed diagnosis of prostate adenocarcinoma who underwent staging [18F]PSMA-1007 positron emission tomography (PET). Qualitative image analysis was performed independently by three experienced nuclear medicine physicians. Patients were divided in two groups according to the presence/absence of unspecific bone uptake. Clinical information, blood count parameters (assessed within 3 months to the PET scan), body mass index (BMI), and bone density as estimated by computed tomography were collected. The Kruskal-Wallis and t-test were used to compare parameters.

RESULTS

We analyzed 77 patients: 29 of them (38%) had unspecific bone uptake at [18F]PSMA-1007 PET, most commonly in the pelvic bones (69%) and ribs (62%). We did not find any significant difference in clinical parameters in the two groups. In patients with unspecific bone uptake, white blood cell, and neutrophil counts were significantly higher; in the same group, we observed lower values of BMI and bone density, although not statistically different.

CONCLUSIONS

We observed unspecific bone uptake on [18F]PSMA-1007 PET in more than 1/3 of patients. In this exploratory analysis, we found a significant correlation between blood count parameters and unspecific [18F]PSMA-1007 bone uptake. We may speculate that [18F]PSMA-1007 unspecific bone uptake could be associated with osteoporosis. This hypothesis needs to be further investigated in larger populations and exploring more specific markers of osteoporosis.

Vitamin D and Calcium and Bioavailability of Calcium in Various Calcium Salts

Introduction

The active form of vitamin D, 1,25D3, plays an important function in the metabolism of calcium. The recommended daily INTAKE of Calcium varies from 1300 mg/day during adolescence to 1200 mg/day after the age of 50 years. Similarly, for vitamin D, the recommended daily intake varies from 400 IU/day during adolescence to 1000 IU/day after the age of 70 years. There is an intricate inter-play of homeostasis of calcium led by vitamin D and PTH at various sites like intestine, kidney, and bones. The increased fracture risk due to bone loss and osteoporosis creates a burden on the patient, healthcare provider as well as the health system. As the population grows old worldwide gradually, the long-term sequelae like pain, loss of independence, and institutionalized care will become more pervasive. Behavioral change to incorporate a healthy lifestyle, including optimal calcium and vitamin D intake and physical exercise in adolescence, form the important foundation in the program for osteoporosis prevention.

Conclusion

Increased emphasis on lifestyle modification and nutrition should be given during times of increased bone loss in old age and after menopause.

Ovariectomy induces hyperalgesia accompanied by upregulated estrogen receptor α and protein kinase B in the rat spinal cord

Hormone supplementation is one of the common therapies for menopause-related disorders. Among different tools, the ovariectomy (OVX) rodents are widely accepted as an appropriate menopausal pain model. Our previous study has showed that OVX produces a significant pain facilitation in both acute pain and tonic pain, however, the underlying mechanisms remain unclear. In this study, we examined the effects of OVX treatment and estradiol (E2) supplementation on formalin-induced nociceptive responses, and explored the associated spinal mechanisms. Female Sprague-Dawley rats underwent bilateral OVX, and E2 supplementation was given subcutaneously from the 5th week after surgery (30 μg/day for 7 days). Our results showed that formalin-induced nociceptive behaviors did not differ between diestrus and proestrus stages of the estrous in intact rats. However, OVX exacerbated formalin-evoked inflammatory pain, especially in the late phase at 4-5 weeks but not 2 weeks post-surgery. E2 supplementation significantly reversed the OVX-triggered hyperalgesia. Double immunofluorescence staining revealed that both ERα and ERβ in the spinal dorsal horn were co-labeled with the neuronal markers, but not with markers of astrocytes or microglia. The spinal ERα (but not ERβ) expression significantly increased in the OVX group, which was reversed by E2 supplementation. Moreover, the OVX individuals showed an increased protein kinase B (AKT) level in lumbar spinal cord, and E2 supplementation diminished the AKT expression in OVX rats. Finally, intrathecal injection Wortmannin, an inhibitor for AKT signaling, effectively reduced the nociceptive behaviors in the late phase and the number of c-fos positive cells. Together, our findings indicate that E2 supplementation alleviates the OVX-induced hyperalgesia, which might be involved in spinal ERα and AKT mechanisms.