Bone turnover: Biology and assessment tools

A non-invasive measure of bone growth in mammals: Validating urinary CTX-I as a bone resorption marker through long-bone growth velocity in bonobos

Assessing bone growth trajectories in mammals is crucial for understanding life history dynamics, but the quantification of bone growth in natural settings can be challenging. Bone resorption markers that can be measured in urine, such as C-telopeptide of type I collagen (CTX-I), offer a non-invasive solution to assess bone growth. Although measurement of urinary CTX-I levels has been applied extensively in human studies, its use in other species is so far limited to a few clinical studies. To validate urinary CTX-I as a bone resorption marker under less controlled conditions, we investigated within-individual day-to-day variation, diurnal patterns, and sex and age-specific variation in zoo-housed bonobos (Pan paniscus). We then also correlated urinary CTX-I levels with forearm growth velocity measures. We found a day-to-day variability in urinary CTX-I levels of around 25%, comparable to human variation. Diurnally, CTX-I levels decreased, aligning with observations in humans and other species. Both sexes showed an age-related decline in urinary CTX-I levels, with a steady decrease after the age of 10 years. Additionally, we found a positive correlation between forearm growth velocity and urinary CTX-I levels across age in female, but not in male, bonobos. Our results demonstrate that urinary CTX-I levels are a meaningful measure of bone growth and highlight its potential to examine bone growth trajectories also in wild populations to investigate life history dynamics.

FGF21 agonists: An emerging therapeutic for metabolic dysfunction-associated steatohepatitis and beyond

The worldwide epidemics of obesity, hypertriglyceridemia, dyslipidaemia, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) represent a major economic burden on healthcare systems. Patients with at-risk MASH, defined as MASH with moderate or significant fibrosis, are at higher risk of comorbidity/mortality, with a significant risk of cardiovascular diseases and/or major adverse liver outcomes. Despite a high unmet medical need, there is only one drug approved for MASH. Several drug candidates have reached the phase III development stage and could lead to several potential conditional drug approvals in the coming years. Within the armamentarium of future treatment options, FGF21 analogues hold an interesting position thanks to their pleiotropic effects in addition to their significant effect on both MASH resolution and fibrosis improvement. In this review, we summarise preclinical and clinical data from FGF21 analogues for MASH and explore additional potential therapeutic indications.

Efficacy and safety of zoledronic acid in the treatment of osteoporosis: A meta-analysis of randomized controlled trials

Purpose

Zoledronic acid can inhibit the activity of osteoclasts, and thus, may slow or inhibit bone loss. The purpose of this study was to systematically evaluate the efficacy and safety of zoledronic acid in the treatment of osteoporosis.

Methods

Four databases, PubMed, Embase, Cochrane Library, and Web of Science, were systematically searched up to December 26, 2022. The primary outcomes included bone mineral density (BMD), carboxy-terminal cross-linked telopeptide of type 1 collagen (CTX), bone-specific alkaline phosphatase (BSAP), procollagen type 1 N-terminal prope-ptide (P1NP), adverse events, and fracture. Secondary outcomes included serum sclerostin level, Visual Analogue Scale (VAS) score, and Oswestry Disability Index (ODI).

Results

A total of 22 randomized controlled trials were included in this meta-analysis. Meta-analysis results showed that zoledronic acid was effective in increasing BMD of the lumbar spine, femoral neck, trochanter and serum sclerostin level; and reduced CTX, BSAP, P1NP, VAS score, and ODI in patients with osteoporosis. Regarding safety, zoledronic acid could reduce the incidence of fractures but had relatively more adverse events.

Conclusion

Zoledronic acid can significantly improve BMD of the lumbar spine, femoral neck and trochanter, and effectively reduce incidence of fracture in patients with osteoporosis, thereby significantly improving patients' quality of life. However, the incidence of adverse events was higher than that of patients treated with placebo.

The specificities, influencing factors, and medical implications of bone circadian rhythms

Physiological processes within the human body are regulated in approximately 24-h cycles known as circadian rhythms, serving to adapt to environmental changes. Bone rhythms play pivotal roles in bone development, metabolism, mineralization, and remodeling processes. Bone rhythms exhibit cell specificity, and different cells in bone display various expressions of clock genes. Multiple environmental factors, including light, feeding, exercise, and temperature, affect bone diurnal rhythms through the sympathetic nervous system and various hormones. Disruptions in bone diurnal rhythms contribute to the onset of skeletal disorders such as osteoporosis, osteoarthritis and skeletal hypoplasia. Conversely, these bone diseases can be effectively treated when aimed at the circadian clock in bone cells, including the rhythmic expressions of clock genes and drug targets. In this review, we describe the unique circadian rhythms in physiological activities of various bone cells. Then we summarize the factors synchronizing the diurnal rhythms of bone with the underlying mechanisms. Based on the review, we aim to build an overall understanding of the diurnal rhythms in bone and summarize the new preventive and therapeutic strategies for bone disorders.

Bone: A Neglected Endocrine Organ?

Bone has traditionally been viewed in the context of its structural contribution to the human body. Foremost providing necessary support for mobility, its roles in supporting calcium homeostasis and blood cell production are often afterthoughts. Recent research has further shed light on the ever-multifaceted role of bone and its importance not only for structure, but also as a complex endocrine organ producing hormones responsible for the autoregulation of bone metabolism. Osteocalcin is one of the most important substances produced in bone tissue. Osteocalcin in circulation increases insulin secretion and sensitivity, lowers blood glucose, and decreases visceral adipose tissue. In males, it has also been shown to enhance testosterone production by the testes. Neuropeptide Y is produced by various cell types including osteocytes and osteoblasts, and there is evidence suggesting that peripheral NPY is important for regulation of bone formation. Hormonal disorders are often associated with abnormal levels of bone turnover markers. These include commonly used bone formation markers (bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide) and commonly used resorption markers (serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen, and tartrate-resistant acid phosphatase type 5b). Bone, however, is not exclusively comprised of osseous tissue. Bone marrow adipose tissue, an endocrine organ often compared to visceral adipose tissue, is found between trabecula in the bone cortex. It secretes a diverse range of hormones, lipid species, cytokines, and other factors to exert diverse local and systemic effects.

Osteoking prevents bone loss and enhances osteoblastic bone formation by modulating the AGEs/IGF-1/β-catenin/OPG pathway in type 2 diabetic db/db mice

Type 2 diabetic osteoporosis (T2DOP) is a skeletal metabolic syndrome characterized by impaired bone remodeling due to type 2 diabetes mellitus, and there are drawbacks in the present treatment. Osteoking (OK) is widely used for treating fractures and femoral head necrosis. However, OK is seldom reported in the field of T2DOP, and its role and mechanism of action need to be elucidated. Consequently, this study investigated whether OK improves bone remodeling and the mechanisms of diabetes-induced injury. We used db/db mice as a T2DOP model and stimulated MC3T3-E1 cells (osteoblast cell line) with high glucose (HG, 50 mM) and advanced glycation end products (AGEs, 100 µg/mL), respectively. The effect of OK on T2DOP was assessed using a combined 3-point mechanical bending test, hematoxylin and eosin staining, and enzyme-linked immunosorbent assay. The effect of OK on enhancing MC3T3-E1 cell differentiation and mineralization under HG and AGEs conditions was assessed by an alkaline phosphatase activity assay and alizarin red S staining. The AGEs/insulin-like growth factor-1(IGF-1)/β-catenin/osteoprotegerin (OPG) pathway-associated protein levels were assayed by western blot analysis and immunohistochemical staining. We found that OK reduced hyperglycemia, attenuated bone damage, repaired bone remodeling, increased tibial and femoral IGF-1, β-catenin, and OPG expression, and decreased receptor activator of nuclear kappa B ligand and receptor activator of nuclear kappa B expression in db/db mice. Moreover, OK promoted the differentiation and mineralization of MC3T3-E1 cells under HG and AGEs conditions, respectively, and regulated the levels of AGEs/IGF-1/β-catenin/OPG pathway-associated proteins. In conclusion, our results suggest that OK may lower blood glucose, alleviate bone damage, and attenuate T2DOP, in part through activation of the AGEs/IGF-1/β-catenin/OPG pathway.

Correlation study between bone metabolic markers, bone mineral density, and sarcopenia

OBJECTIVE

To investigate the correlation between bone metabolism markers, bone mineral density (BMD), and sarcopenia.

METHODS

A total of 331 consecutive patients aged ≥ 60 years who were hospitalized between November 2020 and December 2021 were enrolled. Participants were divided into sarcopenia and non-sarcopenia groups according to the Asian Working Group on Sarcopenia criteria (AWGS, 2019). The clinical data, bone metabolism markers (β-CTX, N-MID, and TP1NP), and BMD were compared between the two groups.

RESULTS

Age, β-CTX, and N-MID of the sarcopenia group were higher than those of the non-sarcopenia group (P < 0.05), but the BMD T values were lower than those of the non-sarcopenia group (P < 0.05). Binary logistic regression analysis showed that increased femoral neck BMD (FNBMD) was a protective factor for sarcopenia, while increased β-CTX was a risk factor. Pearson/Spearman correlation analysis showed that the diagnostic indices of sarcopenia were positively correlated with FNBMD and negatively correlated with β-CTX and N-MID. Multiple linear regression analysis revealed that BMI and FNBMD significantly positively affected muscle strength and appendicular skeletal muscle mass (ASM). The FNBMD significantly positively affected physical performance, while β-CTX significantly negatively affected muscle strength, ASM, and physical performance.

CONCLUSION

Increased FNBMD may be a protective factor against sarcopenia, and increased β-CTX may be a risk factor. The FNBMD significantly positively affected the diagnostic indices of sarcopenia, while β-CTX significantly negatively affected them. BMD and bone metabolism marker levels may be considered in early screening for sarcopenia.

Immunosenescence and inflammaging: Conspiracies against alveolar bone turnover

OBJECTIVE

Inflammaging and immunosenescence are characteristics of senescent immune system alterations. This review provides insights into inflammaging and immunosenescence in periodontitis and focuses on the innerlink of inflammaging and immunosenescence in alveolar bone turnover from a perspective of cell-cell interaction.

METHODS

This review is conducted by a narrative approach to discuss the effect of inflammaging and immunosenescence in aging-related alveolar bone loss. A comprehensive literature research in PubMed and Google was applied to identify reports in English.

RESULTS

Inflammaging is concerned with abnormal M1 polarization and increasing circulating inflammatory cytokines, while immunosenescence involves reduced infection and vaccine responses, depressed antimicrobial function, and infiltration of aged B cells and memory T cells. TLR-mediated inflammaging and altered adaptive immunity significantly affect alveolar bone turnover and aggravate aging-related alveolar bone loss. Besides, energy consumption also plays a vital role in aged immune and skeletal system of periodontitis.

CONCLUSIONS

Senescent immune system exerts a significant function in aging-related alveolar bone loss. Inflammaging and immunosenescence interact functionally and mechanistically, which affects alveolar bone turnover. Therefore, further clinical treatment strategies targeting alveolar bone loss could be based on the specific molecular mechanism connecting inflammaging, immunosenescence, and alveolar bone turnover.

Composite PCL Scaffold With 70% β-TCP as Suitable Structure for Bone Replacement

OBJECTIVES

The purpose of this work was to optimise printable polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP) biomaterials with high percentages of β-TCP endowed with balanced mechanical characteristics to resemble human cancellous bone, presumably improving osteogenesis.

METHODS

PCL/β-TCP scaffolds were obtained from customised filaments for fused deposition modelling (FDM) 3D printing with increasing amounts of β-TCP. Samples mechanical features, surface topography and wettability were evaluated as well as cytocompatibility assays, cell adhesion and differentiation.

RESULTS

The parameters of the newly fabricated materila were optimal for PCL/β-TCP scaffold fabrication. Composite surfaces showed higher hydrophilicity compared with the controls, and their surface roughness sharply was higher, possibly due to the presence of β-TCP. The Young's modulus of the composites was significantly higher than that of pristine PCL, indicating that the intrinsic strength of β-TCP is beneficial for enhancing the elastic modulus of the composite biomaterials. All novel composite biomaterials supported greater cellular growth and stronger osteoblastic differentiation compared with the PCL control.

CONCLUSIONS

This project highlights the possibility to fabricat, through an FDM solvent-free approach, PCL/β-TCP scaffolds of up to 70 % concentrations of β-TCP. overcoming the current lmit of 60 % stated in the literature. The combination of 3D printing and customised biomaterials allowed production of highly personalised scaffolds with optimal mechanical and biological features resembling the natural structure and the composition of bone. This underlines the promise of such structures for innovative approaches for bone and periodontal regeneration.

Genetic disruption of Ano5 leads to impaired osteoclastogenesis for gnathodiaphyseal dysplasia

OBJECTIVES

Gnathodiaphyseal dysplasia (GDD; OMIM#166260) is a rare skeletal genetic disorder characterized by sclerosis of tubular bones and cemento-osseous lesions in mandibles. TMEM16E/ANO5 gene mutations have been identified in patients with GDD. Here, Ano5 knockout (Ano5-/-) mice with enhanced osteoblastogenesis were used to investigate whether Ano5 disruption affects osteoclastogenesis.

SUBJECTS AND METHODS

The maturation of osteoclasts, formation of F-actin ring and bone resorption were detected by immunohistochemistry, TRAP, phalloidin staining and Coming Osteo assays. The expression of osteoclast-related factors was measured by qRT-PCR. Early signaling pathways were verified by western blot.

RESULTS

Ano5-/- mice exhibited inhibitory formation of multinucleated osteoclasts with a reduction of TRAP activity. The expression of Nfatc1, c-Fos, Trap, Ctsk, Mmp9, Rank and Dc-stamp was significantly decreased in bone tissues and bone marrow-derived macrophages (BMMs) of Ano5-/- mice. Ano5-/- osteoclasts manifested disrupted actin ring and less mineral resorption. RANKL-induced early signaling pathways were suppressed in Ano5-/- osteoclasts and Ano5 knockdown RAW264.7 cells. Moreover, the inhibitory effects of NF-κB signalling pathway on osteoclastogenesis were partially attenuated with NF-κB signalling activator.

CONCLUSIONS

Ano5 deficiency impairs osteoclastogenesis, which leads to enhanced osteogenic phenotypes mediated by bone homeostasis dysregulation.

Anti-osteoporotic effects of Yi Mai Jian on bone metabolism of ovariectomized rats

Yi Mai Jian herbal formula (YMJ) is formulated with Eucommiae Folium, Astragali Radix, Ligustri Lucidi Fructus, and Elaeagnus Fructus to improve bone function in traditional Chinese medicine. The anti-osteoporotic effects of YMJ in bone metabolism were evaluated in ovariectomized (OVX) rats. The skeletal structure of the femur and vertebrae was analyzed after treating OVX rats with YMJ for 114 days. The results showed that YMJ significantly increased the bone mineral density (BMD) and trabecular number (Tb. N) of the femur and 5th lumbar vertebrae and reduced trabecular separation (Tb. Sp). Moreover, trabecular bone volume/total tissue volume (BV/TV), bone stiffness, and maximum femur load were significantly increased. The serum concentrations of NTX1 and PYD were significantly decreased. According to these results, YMJ could ameliorate osteoporosis in ovariectomized rats. Eucommiae Folium and Elaeagnus Fructus inhibited osteoclast differentiation, Ligustri Lucidi Fructus inhibited calcium reabsorption, Astragali Radix stimulated osteoblast proliferation, and Astragali Radix and Eucommiae Folium stimulated mineralization. Therefore, the combination of the four herbs into one formula, YMJ, could alleviate bone remodeling caused by low estrogen levels. We suggest that YMJ could be a healthy food candidate for preventing post-menopausal osteoporosis.

METTL3-mediated m6A modification of SOX4 regulates osteoblast proliferation and differentiation via YTHDF3 recognition

N6-methyladenosine (m6A), the most prevalent internal modification in mRNA, is related to the pathogenesis of osteoporosis (OP). Although methyltransferase Like-3 (METTL3), an m6A transferase, has been shown to mitigate OP progression, the mechanisms of METTL3-mediated m6A modification in osteoblast function remain unclear. Here, fluid shear stress (FSS) induced osteoblast proliferation and differentiation, resulting in elevated levels of METTL3 expression and m6A modification. Through Methylated RNA Immunoprecipitation Sequencing (MeRIP-seq) and Transcriptomic RNA Sequencing (RNA-seq), SRY (Sex Determining Region Y)-box 4 (SOX4) was screened as a target of METTL3, whose m6A-modified coding sequence (CDS) regions exhibited binding affinity towards METTL3. Further functional experiments demonstrated that knockdown of METTL3 and SOX4 hampered osteogenesis, and METTL3 knockdown compromised SOX4 mRNA stability. Via RNA immunoprecipitation (RIP) assays, we further confirmed the direct interaction between METTL3 and SOX4. YTH N6-Methyladenosine RNA Binding Protein 3 (YTHDF3) was identified as the m6A reader responsible for modulating SOX4 mRNA and protein levels by affecting its degradation. Furthermore, in vivo experiments demonstrated that bone loss in an ovariectomized (OVX) mouse model was reversed through the overexpression of SOX4 mediated by adeno-associated virus serotype 2 (AAV2). In conclusion, our research demonstrates that METTL3-mediated m6A modification of SOX4 plays a crucial role in regulating osteoblast proliferation and differentiation through its recognition by YTHDF3. Our research confirms METTL3-m6A-SOX4-YTHDF3 as an essential axis and potential mechanism in OP.

Icariin promotes bone marrow mesenchymal stem cells osteogenic differentiation via the mTOR/autophagy pathway to improve ketogenic diet-associated osteoporosis

BACKGROUND

Icariin, a traditional Chinese medicine, has demonstrated anti-osteoporotic properties in ovariectomized mice. However, its effectiveness in preventing bone loss induced by ketogenic diet (KD), which mimics osteoporosis in human, remains unexplored. This study aims to investigate icariin's impact on KD-induced bone loss in mice.

METHODS

Thirty mice were divided into: sham, KD, and KD + icariin groups. Post a 12-week intervention, evaluation including bone microstructures, serum concentrations of tartrate-resistant acid phosphatase (TRAP) and bone-specific alkaline phosphatase (ALP), and femoral tissue expression levels of osteocalcin (OCN) and TRAP. The expression levels of mammalian target of rapamycin (mTOR), ALP, peroxisome proliferator-activated receptor gamma (PPAR-γ), phosphorylated mTOR (p-mTOR), and the autophagy adaptor protein (p62) were also analyzed. Alizarin granule deposition and cellular ALP levels were measured following the induction of bone marrow mesenchymal stem cells (BMSCs) into osteogenesis.

RESULTS

The study found that KD significantly impaired BMSCs' osteogenic differentiation, leading to bone loss. Icariin notably increased bone mass, stimulated osteogenesis, and reduced cancellous bone loss. In the KD + icariin group, measures such as bone tissue density (TMD), bone volume fraction (BV/TV), trabecular number (Tb.N), and trabecular thickness (Tb.Th) were significantly higher than in the KD group. Additionally, bone trabecular separation (Tb.Sp) was markedly lower in the KD + icariin group. Moreover, icariin increased OCN and ALP levels while suppressing PPAR-γ, TRAP, p62, and p-mTOR. In cellular studies, icariin encouraged osteogenic development in BMSCs under KD conditions.

CONCLUSIONS

Icariin effectively counteracts bone thinning and improves bone microstructure. Its mechanism likely involves stimulating BMSCs osteogenic differentiation and inhibiting bone resorption, potentially through mTOR downregulation. These findings suggest icariin's potential as an alternative treatment for KD-induced bone loss.

Denosumab improves trabecular bone score in relationship with decrease in fracture risk of women exposed to aromatase inhibitors

PURPOSE

Trabecular bone score (TBS) is a gray-level textural metric that has shown to correlate with risk of fractures in several forms of osteoporosis. The value of TBS in predicting fractures and the effects of bone-active drugs on TBS in aromatase inhibitors (AIs)-induced osteoporosis are still largely unknown. The primary objective of this retrospective study was to assess the effects of denosumab and bisphosphonates (BPs) on TBS and vertebral fractures (VFs) in women exposed to AIs.

METHODS

241 consecutive women (median age 58 years) with early breast cancer undergoing treatment with AIs were evaluated for TBS, bone mineral density (BMD) and morphometric VFs at baseline and after 18-24 months of follow-up. During the study period, 139 women (57.7%) received denosumab 60 mg every 6 months, 53 (22.0%) BPs, whereas 49 women (20.3%) were not treated with bone-active drugs.

RESULTS

Denosumab significantly increased TBS values (from 1.270 to 1.323; P < 0.001) accompanied by a significant decrease in risk of VFs (odds ratio 0.282; P = 0.021). During treatment with BPs, TBS did not significantly change (P = 0.849) and incidence of VFs was not significantly different from women untreated with bone-active drugs (P = 0.427). In the whole population, women with incident VFs showed higher decrease in TBS vs. non-fractured women (P = 0.003), without significant differences in changes of BMD at any skeletal site.

CONCLUSIONS

TBS variation predicts fracture risk in AIs treated women. Denosumab is effective to induce early increase of TBS and reduction in risk of VFs.

Assessment of Biochemical Bone Turnover Markers in Polish Healthy Children and Adolescents

BACKGROUND

Assessing bone turnover in paediatric populations is crucial for understanding the physiological changes occurring during skeletal development and identifying potential abnormalities. The objective of this study was to assess osteocalcin (OC), bone alkaline phosphatase (BALP), and C-terminal telopeptide of type I collagen (CTX-I) levels reflecting bone formation and resorption for age and sex in Polish healthy children and adolescents.

MATERIALS AND METHODS

A total of 355 healthy normal-weight children and adolescents (46.5% girls) aged 1-18 years old were recruited. Total body less head (TBLH) and spine L1-L4 were used in children to assess bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Bone marker concentrations were determined by immunoenzymatic methods.

RESULTS

Bone marker levels in girls and boys started with higher values in the first year of life and subsequently decreased until reaching a nadir during the prepubertal period. The pubertal peak values of bone markers were reached at 11-13 years old in boys and at 9-11 years old in girls. After puberty, the adolescents showed a gradual decline in bone marker concentrations to the values observed in adults. We found positive correlations between OC level and TBLH-BMD (r = 0.329, p = 0.002), TBLH-BMD Z-score (r = 0.245, p = 0.023), and L1-L4 BMD (r = 0.280, p = 0.009) in the prepubertal group.

CONCLUSIONS

We showed serum levels of bone turnover markers-BALP, OC, and CTX-I-in relation to age and sex in healthy Polish children and adolescents. The age intervals of these markers for girls and boys aged 1-18 years old may be clinically useful in the assessment of bone metabolism in individuals with skeletal disorders.

Gallium-doped thermochemically treated titanium reduces osteoclastogenesis and improves osteodifferentiation

Excessive bone resorption is one of the main causes of bone homeostasis alterations, resulting in an imbalance in the natural remodeling cycle. This imbalance can cause diseases such as osteoporosis, or it can be exacerbated in bone cancer processes. In such cases, there is an increased risk of fractures requiring a prosthesis. In the present study, a titanium implant subjected to gallium (Ga)-doped thermochemical treatment was evaluated as a strategy to reduce bone resorption and improve osteodifferentiation. The suitability of the material to reduce bone resorption was proven by inducing macrophages (RAW 264.7) to differentiate to osteoclasts on Ga-containing surfaces. In addition, the behavior of human mesenchymal stem cells (hMSCs) was studied in terms of cell adhesion, morphology, proliferation, and differentiation. The results proved that the Ga-containing calcium titanate layer is capable of inhibiting osteoclastogenesis, hypothetically by inducing ferroptosis. Furthermore, Ga-containing surfaces promote the differentiation of hMSCs into osteoblasts. Therefore, Ga-containing calcium titanate may be a promising strategy for patients with fractures resulting from an excessive bone resorption disease.

Inositol 1,4,5-trisphosphate receptor type 2 is associated with the bone-vessel axis in chronic kidney disease-mineral bone disorder

Objective: The pathogenesis of renal osteopathy and cardiovascular disease suggests the disordered bone-vessel axis in chronic kidney disease-mineral bone disorder (CKD-MBD). However, the mechanism of the bone-vessel axis in CKD-MBD remains unclear.Methods: We established a CKD-MBD rat model to observe the pathophysiological phenotype of the bone-vessel axis and performed RNA sequencing of aortas to identify novel targets of the bone-vessel axis in CKD-MBD.Results: The microarchitecture of the femoral trabecular bone deteriorated and alveolar bone loss was aggravated in CKD-MBD rats. The intact parathyroid hormone and alkaline phosphatase levels increased, 1,25-dihydroxyvitamin D3 levels decreased, and intact fibroblast growth factor-23 levels did not increase in CKD-MBD rats at 16 weeks; other bone metabolic parameters in the serum demonstrated dynamic characteristics. With calcium deposition in the abdominal aortas of CKD-MBD rats, RNA sequencing of the aortas revealed a significant decrease in inositol 1,4,5-trisphosphate receptor type 2 (ITPR2) gene levels in CKD-MBD rats. A similar trend was observed in rat aortic smooth muscle cells. As a secretory protein, ITPR2 serum levels decreased at 4 weeks and slightly increased without statistical differences at 16 weeks in CKD-MBD rats. ITPR2 serum levels were significantly increased in patients with vascular calcification, negatively correlated with blood urea nitrogen levels, and positively correlated with serum tartrate-resistant acid phosphatase 5b levels.Conclusion: These findings provide preliminary insights into the role of ITPR2 in the bone-vessel axis in CKD-MBD. Thus, ITPR2 may be a potential target of the bone-vessel axis in CKD-MBD.

Bone turnover biomarkers predict one-year all-cause mortality and walking ability in geriatric hip fracture patients

PURPOSE

To investigate the utility of serum C-terminal cross-linking telopeptides (β-CTX) and procollagen type I N propeptide (PINP) for predicting one-year mortality and walking ability in Chinese geriatric hip fracture patients who underwent surgical interventions.

METHOD

Elderly patients (≥ 60 years) who underwent surgical interventions for unilateral low-energy hip fracture from 2015 to 2020 in our center were included. Demographic data was retrospectively retrieved from the electronic medical database. The PINP and β-CTX concentrations were measured before the surgery. The patients were divided into two groups according to the outcome of mortality and walking ability after hip surgery, respectively. β-CTX and PINP were divided into four grades based on quartiles [Quartile(Q)1-4] for further analysis. All the variables with p < 0.1 in univariable analysis were included in a multivariable model.

RESULTS

In univariable analysis, the levels of serum β-CTX (p = 0.007) and PINP (p = 0.025) was associated with one-year mortality, while the association between levels of serum β-CTX (p = 0.072) or PINP (p = 0.055) with one-year disability was marginally significant. After adjustment for confounders, the relative risk [OR (95 % CI), Q4 v sQ1, p-value] of one-year mortality and one-year disability were 7.28 (2.08-29.78, p = 0.003) and 3.97 (1.44-11.69, p = 0.009) for β-CTX and 5.87 (1.70-23.80, p = 0.008) and 3.48 (1.30-9.93, p = 0.016) for PINP, respectively. The coefficient of determination, AUC and bias-corrected C-index of predictive models based on previously reported predictors were significantly improved after integrating β-CTX or PINP.

CONCLUSION

Higher serum β-CTX and PINP are independently associated with an increased risk of one-year mortality and disability in patients with hip fractures. The application of BTMs improves the performance of currently available predictive models.

Conjugated linoleic acid and glucosamine supplements may prevent bone loss in aging by regulating the RANKL/RANK/OPG pathway

The skeleton is a living organ that undergoes constant changes, including bone formation and resorption. It is affected by various diseases, such as osteoporosis, osteopenia, and osteomalacia. Nowadays, several methods are applied to protect bone health, including the use of hormonal and non-hormonal medications and supplements. However, certain drugs like glucocorticoids, thiazolidinediones, heparin, anticonvulsants, chemotherapy, and proton pump inhibitors can endanger bone health and cause bone loss. New studies are exploring the use of supplements, such as conjugated linoleic acid (CLA) and glucosamine, with fewer side effects during treatment. Various mechanisms have been proposed for the effects of CLA and glucosamine on bone structure, both direct and indirect. One mechanism that deserves special attention is the regulatory effect of RANKL/RANK/OPG on bone turnover. The RANKL/RANK/OPG pathway is considered a motive for osteoclast maturation and bone resorption. The cytokine system, consisting of the receptor activator of the nuclear factor (NF)-kB ligand (RANKL), its receptor RANK, and its decoy receptor, osteoprotegerin (OPG), plays a vital role in bone turnover. Over the past few years, researchers have observed the impact of CLA and glucosamine on the RANKL/RANK/OPG mechanism of bone turnover. However, no comprehensive study has been published on these supplements and their mechanism. To address this gap in knowledge, we have critically reviewed their potential effects. This review aims to assist in developing efficient treatment strategies and focusing future studies on these supplements.

Effect of SGLT2 inhibitors on fractures, BMD, and bone metabolism markers in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

This meta-analysis aims to evaluate the impact of Sodium Glucose Transporter 2 (SGLT2) inhibitors on fractures, bone mineral density (BMD), and bone metabolism markers in type 2 diabetes mellitus (T2DM) patients. Pooled relative risk (RR) with 95% confidence interval (CI) assessed the relationship between SGLT2 inhibitors and fracture risk. Weighted mean difference (WMD) with 95% CI explored the correlation between SGLT2 inhibitors and BMD, as well as bone metabolism markers. A total of 20 randomised controlled trials (RCTs) involving 12,764 patients were analysed. No significant association emerged between SGLT2 inhibitor use and elevated fracture risk (pooled RR = 1.21, 95% CI [0.95, 1.54], I2 = 22%). Furthermore, SGLT2 inhibitors exhibited no substantial effects on BMD changes at the lumbar spine (WMD = -0.02, 95% CI [-0.38, 0.34]), femoral neck (WMD = 0.11, 95% CI [-0.28, 0.50]), total hip (WMD = -0.20, 95% CI [-0.41, 0.01]), and distal forearm (WMD = -0.20, 95% CI [-0.62, 0.22]). Similarly, no notable impact of SGLT2 inhibitors on bone metabolism markers, including CTX (WMD = 0.04, 95% CI [-0.02, 0.09]), P1NP (WMD = 1.06, 95% CI [-0.44, 2.57]), PTH (WMD = 0.34, 95% CI [-0.07, 0.75]), calcium (WMD = 0.01, 95% CI [-0.02, 0.04]), and phosphate (WMD = 2.37, 95% CI [-0.76, 5.49]). The findings suggest that the utilization of SGLT2 inhibitors is not significantly linked to an elevated risk of fractures in individuals with T2DM. However, further clinical investigations and extended follow-up periods are warranted to establish more conclusive determinations.

Safety and efficacy of once-weekly efruxifermin versus placebo in non-alcoholic steatohepatitis (HARMONY): a multicentre, randomised, double-blind, placebo-controlled, phase 2b trial

BACKGROUND

Fibroblast growth factor 21 (FGF21) regulates metabolism and protects cells against stress. Efruxifermin is a bivalent Fc-FGF21 analogue that replicates FGF21 agonism of fibroblast growth factor receptor 1c, 2c, or 3c. The aim of this phase 2b study was to assess its efficacy and safety in patients with non-alcoholic steatohepatitis (NASH) and moderate (F2) or severe (F3) fibrosis.

METHODS

HARMONY is a multicentre, randomised, double-blind, placebo-controlled, 96-week, phase 2b trial that was initiated at 41 clinics in the USA. Adults with biopsy-confirmed NASH, defined by a non-alcoholic fatty liver disease activity score (NAS) of 4 or higher and scores of 1 or higher in each of steatosis, ballooning, and lobular inflammation, with histological stage F2 or F3 fibrosis, were randomly assigned (1:1:1), via an interactive response system, to receive placebo or efruxifermin (28 mg or 50 mg), subcutaneously once weekly. Patients, investigators, pathologists, site staff, and the sponsor were masked to group assignments during the study. The primary endpoint was the proportion of patients with improvement in fibrosis of at least 1 stage and no worsening of NASH, based on analyses of baseline and week 24 biopsies (liver biopsy analysis set [LBAS]). A sensitivity analysis evaluated the endpoint in the full analysis set (FAS), for which patients with missing biopsies were considered non-responders. This trial is registered with ClinicalTrials.gov, NCT04767529, and is ongoing.

FINDINGS

Between March 22, 2021, and Feb 7, 2022, 747 patients were assessed for eligibility and 128 patients (mean age 54·7 years [SD 10·4]; 79 [62%] female and 49 male [38%]; 118 [92%] white; and 56 [41%] Hispanic or Latino) were enrolled and randomly assigned to receive placebo (n=43), efruxifermin 28 mg (n=42; two randomised patients were not dosed because of an administrative error), or efruxifermin 50 mg (n=43). In the LBAS (n=113), eight (20%) of 41 patients in the placebo group had an improvement in fibrosis of at least 1 stage and no worsening of NASH by week 24 versus 15 (39%) of 38 patients in the efruxifermin 28 mg group (risk ratio [RR] 2·3 [95% CI 1·1-4·8]; p=0·025) and 14 (41%) of 34 patients in the efruxifermin 50 mg group (2·2 [1·0-5·0]; p=0·036). Based on the FAS (n=128), eight (19%) of 43 patients in the placebo group met this endpoint versus 15 (36%) of 42 in the efruxifermin 28 mg group (RR 2·2 [95% CI 1·0-4·8]; p=0·033) and 14 (33%) of 43 in the efruxifermin 50 mg group (1·9 [0·8-4·3]; p=0·123). The most frequent efruxifermin-related adverse events were diarrhoea (16 [40%] of 40 patients in the efruxifermin 28 mg group and 17 [40%] of 43 patients in efruxifermin 50 mg group vs eight [19%] of 43 patients in the placebo group; all events except one were grade 1-2) and nausea (11 [28%] patients in the efruxifermin 28 mg group and 18 [42%] patients in the efruxifermin 50 mg group vs ten [23%] patients in the placebo group; all grade 1-2). Five patients (two in the 28 mg group and three in the 50 mg group) discontinued due to adverse events. Serious adverse events occurred in four patients in the 50 mg group; one was defined as drug related (ulcerative esophagitis in a participant with a history of gastro-oesophageal reflux disease). No deaths occurred.

INTERPRETATION

Efruxifermin improved liver fibrosis and resolved NASH over 24 weeks in patients with F2 or F3 fibrosis, with acceptable tolerability, supporting further assessment in phase 3 trials.

FUNDING

Akero Therapeutics.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

Bone is a tissue that is active throughout the lifespan, and its physiological activities, such as growth, development, absorption, and formation, are always ongoing. All types of stimulation that occur in sports play an important role in regulating the physiological activities of bone. Here, we track the latest research progress locally and abroad, summarize the recent, relevant research results, and systematically summarize the effects of different types of exercise on bone mass, bone strength and bone metabolism. We found that different types of exercise have different effects on bone health due to their unique technical characteristics. Oxidative stress is an important mechanism mediating the exercise regulation of bone homeostasis. Excessive high-intensity exercise does not benefit bone health but induces a high level of oxidative stress in the body, which has a negative impact on bone tissue. Regular moderate exercise can improve the body's antioxidant defense ability, inhibit an excessive oxidative stress response, promote the positive balance of bone metabolism, delay age-related bone loss and deterioration of bone microstructures and have a prevention and treatment effect on osteoporosis caused by many factors. Based on the above findings, we provide evidence for the role of exercise in the prevention and treatment of bone diseases. This study provides a systematic basis for clinicians and professionals to reasonably formulate exercise prescriptions and provides exercise guidance for patients and the general public. This study also provides a reference for follow-up research.

Multi-omics analysis of bone marrow mesenchymal stem cell differentiation differences in osteoporosis

Osteoporosis is a systemic skeletal disease characterized by low bone mass and degradation of bone tissue microarchitecture, leading to enhanced bone fragility and increased fracture risk. However, the pathogenesis of osteoporosis is unclear. Our results showed that BMSCs dervied from ovariectomized rats had a higher capacity for osteogenesis and lipogenic differentiation compared to the control group. In the meantime, we identified a total of 205 differentially expressed proteins and 2294 differentially expressed genes in BMSCs isolated from ovariectomized rats by proteomics analysis and transcriptome sequencing, respectively. These differentially expressed proteins and genes were mainly involved in ECM-receptor interaction signaling pathway. We speculate that BMSCs derived from ovariectomized rats have a higher potential for bone formation because expression of ECM collagen or genes encoding collagen in the bone ECM in BMSCs isolated from ovariectomized rats are increased compared with that from control group, which provided the prerequisite for the increased bone turnover effect. To conclusion, our results may provid new ideas for further research on the pathogenesis of osteoporosis.

The mechanism of metformin combined with total flavonoids of Rhizoma Drynariae on ovariectomy-induced osteoporotic rats

The present study evaluated the in vitro effect of metformin (Met) and total flavonoids of Rhizoma Drynariae (TFRD) on osteoclasts, osteocytes, and osteoblasts at different stages. We also assessed the effect and mechanism of treatment with Met combined with TFRD on ovariectomy (OVX)-induced osteoporosis in rats. The results showed that Met combined with TFRD significantly promoted the migration of osteoprogenitor cells and stimulated the differentiation and maturation of osteoblast precursor cells. Furthermore, Met combined with TFRD treatment significantly inhibited the osteogenic inhibitor sclerostin (SOST)/dickkopf 1 (DKK1) protein expression and the osteoclast differentiation factor receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) ratio in osteocytes. In the in vivo study, Met combined with TFRD effectively reduced bone resorption markers levels, including type-I collagen carboxy-terminal peptide (CTX-1) and tartrate-resistant acid phosphatase (TRAP), and remarkably increased the bone formation marker propeptide of type I procollagen (PINP) level in the serum of rats with osteoporosis. Met combined with TFRD treatment improved bone mineral density (BMD), trabecular microstructure, and mechanical properties of osteoporotic rats. Mechanistically, Met combined with TFRD downregulated SOST and DKK1 levels, and upregulated Wnt10b, β-catenin, runt-related transcription factor 2 (Runx2) et al. Meanwhile, Met combined with TFRD treatment reduced the RANKL/OPG ratio, and reduced the receptor activator of nuclear factor-κB (RANK), nuclear factor of activated T cells c1 (NFATC1), and TRAP levels. In conclusion, Met combined with TFRD ameliorated bone mass in osteoporotic rats through regulating Wnt/β-catenin signaling pathway and OPG/RANKL/RANK axis.

Lipid Peroxidation as a Possible Factor Affecting Bone Resorption in Obese Subjects-Preliminary Research

Oxidative stress, which promotes bone catabolism, also affects the quality of bone tissue. We aimed to assess the impact of metabolic disorders and oxidant-antioxidant imbalance associated with primary obesity on bone resorption and formation processes. Anthropometric parameters, metabolic variables, oxidative stress indicators (malondialdehyde, vitamins A and E, uric acid, superoxide dismutase, catalase, glutathione peroxidase, type 1 paraoxonase, iron-reducing plasma antioxidant power) and markers of bone turnover (type I procollagen N-terminal propeptide and the type I collagen C-terminal cross-linked telopeptide; P1NP and CTX) were assessed in 108 Polish participants. Under the influence of oxidative stress, both enzymatic and non-enzymatic defense mechanisms were stimulated in obese subjects, especially in women, who had increased lipid peroxidation and activity of catalase (particularly in first-degree obesity) and decreased vitamin E concentration. The process of lipid peroxidation, as well as the weakening of the bone formation, was strongly manifested in women at a BMI range of 35.0-39.9 kg/m² but not at BMI > 40.0 kg/m², but it had a comprehensive negative impact on bone turnover in obese men. Obesity and its degree of advancement significantly affected the decrease in the concentration of the marker of bone formation-P1NP-only in the plasma of women. Excessive body weight had no effect on the value of the bone resorption marker in plasma, regardless of gender. Our results confirm the existence of the "obesity paradox" in the aspect of bone tissue metabolism and suggest that a specific body weight threshold changed the molecular response of the tissue.

Bone Turnover Markers in Adults with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Objective

Previous studies suggested that the level of bone turnover markers (BTMs) could be altered in patients with nonalcoholic fatty liver disease (NAFLD). We aim to provide a comprehensive understanding on the associations between BTMs and NAFLD in adults with a meta-analysis.

Methods

Articles published up to January 31, 2023, were systematically searched in PubMed, Web of Science, Cochrane database, Embase, and CNKI. The search formula is as follows: "nonalcoholic fatty liver disease" combined with the terms that bone turnover markers such as "osteocalcin," "collagen type I trimeric cross-linked peptide," and "procollagen type I N-terminal peptide." Stata 15.0 software was used to calculate the pooled OR (95% CI) and perform the heterogeneity test, sensitivity analysis, and publication bias.

Results

We identified 18 studies with a total of 12,310 participants. Statistical differences were found between patients with NAFLD compared to the control group for osteocalcin (n = 15 studies; SMD: -0.69; 95% CI: -0.73--0.64; P=0.002), procollagen type I N-terminal propeptide (n = 5 studies; SMD: -0.40; 95% CI: -0.80--0.00; P=0.049), and collagen type I cross-linked C-telopeptide (n = 7 studies; SMD: -0.16; 95% CI: -0.23--0.09); P < 0.001).

Conclusion

Bone turnover markers were lower in patients with NAFLD compared to the control group.

Non-Alcoholic Fatty Liver Disease and Bone Tissue Metabolism: Current Findings and Future Perspectives

Non-alcoholic fatty liver disease (NAFLD) is reaching epidemic proportions worldwide. Moreover, the prevalence of this liver disease is expected to increase rapidly in the near future, aligning with the rise in obesity and the aging of the population. The pathogenesis of NAFLD is considered to be complex and to include the interaction between genetic, metabolic, inflammatory, and environmental factors. It is now well documented that NAFLD is linked to the other conditions common to insulin resistance, such as abnormal lipid levels, metabolic syndrome, and type 2 diabetes mellitus. Additionally, it is considered that the insulin resistance may be one of the main mechanisms determining the disturbances in both bone tissue metabolism and skeletal muscles quality and functions in patients with NAFLD. To date, the association between NAFLD and osteoporosis has been described in several studies, though it worth noting that most of them included postmenopausal women or elderly patients and originated from Asia. However, taking into account the health and economic burdens of NAFLD, and the increasing prevalence of obesity in children and adolescents worldwide, further investigation of the relationship between osteopenia, osteoporosis and sarcopenia in NAFLD, including in young and middle-aged patients, is of great importance. In addition, this will help to justify active screening and surveillance of osteopenia and osteoporosis in patients with NAFLD. In this review, we will discuss various pathophysiological mechanisms and possible biologically active molecules that may interplay between NAFLD and bone tissue metabolism.

Biochemical Markers of Bone Fragility in Patients with Diabetes. A Narrative Review by the IOF and the ECTS

CONTEXT

The risk of fragility fractures is increased in both type 1 and type 2 diabetes. Numerous biochemical markers reflecting bone and/or glucose metabolism have been evaluated in this context. This review summarizes current data on biochemical markers in relation to bone fragility and fracture risk in diabetes.

METHODS

Literature review by a group of experts from the International Osteoporosis Foundation (IOF) and European Calcified Tissue Society (ECTS) focusing on biochemical markers, diabetes, diabetes treatments and bone in adults.

RESULTS

Although bone resorption and bone formation markers are low and poorly predictive of fracture risk in diabetes, osteoporosis drugs seem to change bone turnover markers in diabetics similarly to non-diabetics, with similar reductions in fracture risk. Several other biochemical markers related to bone and glucose metabolism have been correlated with BMD and/or fracture risk in diabetes, including osteocyte-related markers such as sclerostin, HbA1c and advanced glycation end products (AGEs), inflammatory markers and adipokines, as well as IGF-1 and calciotropic hormones.

CONCLUSION

Several biochemical markers and hormonal levels related to bone and/or glucose metabolism have been associated with skeletal parameters in diabetes. Currently, only HbA1c levels seem to provide a reliable estimate of fracture risk, while bone turnover markers could be used to monitor the effects of anti-osteoporosis therapy.

Early renal impairment affects hormonal regulators of calcium and bone metabolism and Wnt signalling and the response to vitamin D supplementation in healthy older adults

Bone and renal metabolism are regulated by common factors and there is extensive cross-talk between these organs (the 'renal-bone-axis'). Ageing is associated with physiological changes including reduced bone mass, renal function and tissue sensitivity to regulatory hormones, impacting the renal-bone axis. We aimed to investigate the influence of estimated Glomerular Filtration Rate (eGFR) on plasma concentrations of vitamin D metabolites, Wnt signalling and bone metabolism in a dose ranging vitamin D₃ RCT (12,000 IU, 24,000 IU, 48,000 IU/month for 1 year; n = 379, >70 y) with a baseline eGFR > 30 mL/min/1.73 m². Participants were categorised on basis of eGFR (≥60 or mL/min/1.73 m²) based on 5 commonly used algorithms for eGFR. Differences between eGFR categories were tested with ANCOVA. Before supplementation commenced, a lower eGFR was associated with significantly higher concentrations of c-terminal and intact Fibroblast Growth Factor-23 (cFGF23; iFGF23), intact Parathyroid Hormone (iPTH) and Sclerostin (SOST) and lower Klotho, 1,25-dihydroxy Vitamin D (1,25(OH)₂D) and Dickkopf-related Protein 1 (DKK1) concentrations. Differences between eGFR groups in 25-hydroxy Vitamin D (25(OH)D), 24,25-dihydroxy Vitamin D (24,25(OH)₂D) and iPTH were only detected with eGFR based on Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification in Diet for Renal Disease (MDRD-4) algorithms. Differences in Bone Mineral Density and Content (BMD; BMC) and bone turnover markers were detected only with Cockcroft-Gault (CG). Pre- and post- supplementation comparisons showed differences in the response to supplementation by eGFR group. Plasma 25(OH)D, 24,25(OH)₂D, 1,25(OH)₂D and DKK1 increased and iPTH and C-terminal telopeptide (CTX) decreased in both groups. Plasma iFGF23, bone specific alkaline phosphatase (BAP) and Procollagen 1 intact N-terminal Propeptide (PINP) increased and phosphate decreased only in the group with eGFR ≥ 60 mL/min/1.73 m². Findings were largely consistent across all eGFR algorithms. Post-supplementation, cFGF23, iFGF23, iPTH and SOST remained significantly higher in the lower eGFR group. Plasma 1,25(OH)₂D and Klotho did no longer differ between eGFR groups. This was found for all eGFR algorithms, with the exception of iPTH and iFGF23, which were not significantly different with eGFR based on CG. Differences in BMD and BMC were detected with CKD-EPI-creatinine and MDRD-4 but not GC. This study showed that even a moderate decline in eGFR is associated with alterations in vitamin D metabolism, Wnt signalling and bone turnover markers. Renal function influenced the response to vitamin D supplementation. Supplementation increased Vitamin D metabolites in the group with moderate renal impairment to concentrations comparable to those found in the group with normal renal function. However, although CTX decreased, an increase in bone formation markers was not found in the group with eGFR 60 mL/min/1.73 m². In conclusion, vitamin D supplementation had beneficial effects on markers of the renal-bone axis in older people with both normal and impaired renal function.

Predisposing factors for a second fragile hip fracture in a population of 1130 patients with hip fractures, treated at Oulu University Hospital in 2013-2016: a retrospective study

OBJECTIVE

The life-time risk of a second fragile hip fracture is 8.4%, but the risk factors that predispose to a second hip fracture remain unresolved. This study aimed to define risk factors that predisposed patients to a second hip fracture.

METHODS

For this retrospective study, we retrieved clinical data on 1130 patients with fragile hip fractures (67.2% female, mean age: 79.3 years) that underwent surgery at the Oulu University Hospital in 2013-2016. These data included the fracture risk assessment score (measured with the FRAX tool), the bone-mass T-score, laboratory values, ambulatory capacity, and the time of death.

RESULTS

In this population, 12.4% of patients sustained a second hip fracture. The predisposing factors for a second hip fracture were: female (p = 0.016), a high FRAX score (p = 0.020), and low physical capacity (p < 0.001). The vitamin D level recommended for treating osteoporosis (i.e., vitamin D > 75 nmol/l) was observed in only 24% of patients, and 42% of patients had ionized calcium levels below the reference range. According to the level of the cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), 37% of patients did not have high bone turnover. We found a positive correlation between age and ICTP (p = 0.001). The risk of death was higher after the second hip fracture (p = 0.005), but we found no difference in age between patients with first and second hip fractures (p = 0.11).

CONCLUSION

After a hip fracture, a second hip fracture is a well-known risk. Nevertheless, we found that only one-third of patients with a second hip fracture had used anti-osteoporosis medication at any time previously. These findings suggested that second hip fractures were most likely to occur in patients with osteopenic T-score values, in women more often than men, and in patients with high FRAX scores and low ambulatory capacity.

Establishment of Reference Intervals for Bone Turnover Markers in Healthy Chinese Older Adults

BACKGROUND

Reference ranges for bone turnover markers (BTMs) are still lacking in the healthy Chinese population.

AIM

To establish reference intervals for BTMs and to investigate the correlations between BTMs and BMD in Chinese older adults.

SUBJECTS AND METHODS

A community-based cross-sectional study was conducted among 2,511 Chinese subjects aged over 50 yrs residing in Zhenjiang, Southeast China. Reference intervals for BTMs (i.e., procollagen type I N-terminal propeptide, P1NP; β cross-linked C-terminal telopeptide of type I collagen, β-CTX) were calculated as the central 95% range of all measurements in Chinese older adults.

RESULTS

The reference intervals of P1NP, β-CTX and P1NP/β-CTX were 15.8-119.9 ng/mL, 0.041-0.675 ng/mL and 49.9-1261.5 for females and 13.6-111.4 ng/mL, 0.038-0.627 ng/mL and 41.0-1269.1 for males, respectively. In the multiple linear regression analysis, only β-CTX was negatively associated with BMD after adjusting for age and body mass index (BMI) in both sex-stratified groups (all P < 0.05).

CONCLUSION

This study established age- and sex-specific reference intervals for BTMs in a large sample of healthy Chinese participants ≥ 50 and < 80 years of age and explored the correlations between BTMs and BMD, which provides an effective reference for the assessment of bone turnover in the clinical practice of osteoporosis.

A Novel Prenylflavonoid Icariside I Ameliorates Estrogen Deficiency-Induced Osteoporosis via Simultaneous Regulation of Osteoblast and Osteoclast Differentiation

Regulation of osteoblast-mediated bone formation and osteoclast-mediated bone resorption is crucial for bone health. Currently, most clinical drugs for osteoporosis treatment such as bisphosphonates are commonly used to inhibit bone resorption but unable to promote bone formation. In this study, we discovered for the first time that icariside I (GH01), a novel prenylflavonoid isolated from Epimedium, can effectively ameliorate estrogen deficiency-induced osteoporosis with enhancement of trabecular and cortical bone in an ovariectomy (OVX) mouse model. Mechanistically, our in vitro results showed that GH01 repressed osteoclast differentiation and resorption through inhibition of RANKL-induced TRAF6-MAPK-p38-NFATc1 cascade. Simultaneously, we also found that GH01 dose-dependently promoted osteoblast differentiation and formation by inhibiting adipogenesis and accelerating energy metabolism of osteoblasts. In addition, both in vitro and in vivo studies also suggested that GH01 is not only a non-toxic natural small molecule but also beneficial for restoration of liver injury in OVX mice. These results demonstrated that GH01 has great potential for osteoporosis treatment by simultaneous regulation of osteoblast and osteoclast differentiation.

The Gut-Bone Axis in Diabetes

PURPOSE OF REVIEW

To describe recent advances in the understanding of how gut-derived hormones regulate bone homeostasis in humans with emphasis on pathophysiological and therapeutic perspectives in diabetes.

RECENT FINDINGS

The gut-derived incretin hormone glucose-dependent insulinotropic polypeptide (GIP) is important for postprandial suppression of bone resorption. The other incretin hormone, glucagon-like peptide 1 (GLP-1), as well as the intestinotrophic glucagon-like peptide 2 (GLP-2) has been shown to suppress bone resorption in pharmacological concentrations, but the role of the endogenous hormones in bone homeostasis is uncertain. For ambiguous reasons, both patients with type 1 and type 2 diabetes have increased fracture risk. In diabetes, the suppressive effect of endogenous GIP on bone resorption seems preserved, while the effect of GLP-2 remains unexplored both pharmacologically and physiologically. GLP-1 receptor agonists, used for the treatment of type 2 diabetes and obesity, may reduce bone loss, but results are inconsistent. GIP is an important physiological suppressor of postprandial bone resorption, while GLP-1 and GLP-2 may also exert bone-preserving effects when used pharmacologically. A better understanding of the actions of these gut hormones on bone homeostasis in patients with diabetes may lead to new strategies for the prevention and treatment of skeletal frailty related to diabetes.

Bone Turnover Markers in Children: From Laboratory Challenges to Clinical Interpretation

Bone turnover markers (BTMs) have been developed many years ago to study, in combination with imaging techniques, bone remodeling in adults. In children and adolescents, bone metabolism differs from adults since it implies both growth and bone remodeling, suggesting an age- and gender-dependent BTM concentration. Therefore, specific studies have evaluated BTMs in not only physiological but also pathological conditions. However, in pediatrics, the use of BTMs in clinical practice is still limited due to these many children-related specificities. This review will discuss about physiological levels of BTMs as well as their modifications under pathological conditions in children and adolescents. A focus is also given on analytical and clinical challenges that restrain BTM usefulness in pediatrics.

Alpinetin alleviates osteoporosis by promoting osteogenic differentiation in BMSCs by triggering autophagy via PKA/mTOR/ULK1 signaling

Osteoporosis, a systemic bone disease that is characterized by a reduction in bone mass and destruction of bone microstructure, is becoming a serious problem worldwide. Bone marrow mesenchymal stem cells (BMSCs) can differentiate into bone-forming osteoblasts, and play an important role in maintaining homeostasis of bone metabolism, thus being a potential therapeutic target for osteoporosis. Although the phytochemical alpinetin (APT) has been reported to possess a variety of pharmacological activities, it is still unclear whether APT can influence the osteogenic differentiation of on BMSCs and if it can improve osteoporosis. In this study, we found that APT treatment was able to enhance osteogenic differentiation levels of human BMSCs in vitro and mouse ones in vivo as revealed by multiple osteogenic markers including increased alkaline phosphatase activity and osteocalcin expression. Mechanistically, the protein kinase A (PKA)/mTOR/ULK1 signaling was involved in the action of APT to enhance the osteogenic differentiation of BMSCs. In addition, oral administration of APT significantly mitigated the bone loss in a dexamethasone-induced mouse model of osteoporosis through strengthening PKA signaling and autophagy. Altogether, these data demonstrate that APT promotes osteogenic differentiation in BMSCs by augmenting the PKA/mTOR/ULK1 autophagy signaling, highlighting its potential therapeutic application for treating osteoporotic diseases.

Role of MOTS-c in the regulation of bone metabolism

MOTS-c, a mitochondrial-derived peptide (MDP), is an essential regulatory mediator of cell protection and energy metabolism and is involved in the development of specific diseases. Recent studies have revealed that MOTS-c promotes osteoblast proliferation, differentiation, and mineralization. Furthermore, it inhibits osteoclast production and mediates the regulation of bone metabolism and bone remodeling. Exercise effectively upregulates the expression of MOTS-c, but the specific mechanism of MOTS-c regulation in bone by exercise remains unclear. Therefore, this article reviewed the distribution and function of MOTS-c in the tissue, discussed the latest research developments in the regulation of osteoblasts and osteoclasts, and proposed potential molecular mechanisms for the effect of exercise on the regulation of bone metabolism. This review provides a theoretical reference for establishing methods to prevent and treat skeletal metabolic diseases.

Vertebral Fractures in Acromegaly: A Systematic Review

INTRODUCTION

Acromegaly is characterized by a very particular alteration of bone microarchitecture, leading to increased vertebral fragility. However, due to inconsistent and insufficient evidence, no guidelines are available for the evaluation of this osteopathy.

METHODS

We performed a literature review of studies published between 1968 and January 2022 on the PubMed and SCOPUS databases using the terms "acromegaly" and "vertebral fractures". Twenty-four studies were found eligible for inclusion, published between June 2005 and November 2021. Included studies evaluated acromegaly patients, who were assessed for the presence of vertebral fractures. We excluded case reports, reviews, meta-analyses, letters to the editor, articles not written in English, and research performed on the same set of patients without significant differences in study design. Risk of bias was avoided by following the ROBIS risk of bias recommendations. We executed rigorous data collection, and the results are depicted as a narrative overview, but also, as statistical synthesis. Limitations of the evidence presented in the study include study heterogeneity, small sample sizes, and a small number of prospective studies with short follow-up.

FINDINGS

Data regarding vertebral fractures (VFs) in acromegaly and their influencing factors are variable. Twenty-four studies were included, nine out of which had a prospective design. The smallest group of acromegaly patients had 18 subjects and the largest included 248 patients. Prevalence ranges between 6.5% and 87.1%, although most studies agree that it is significantly higher than in controls. VFs also have a higher incidence (between 5.6% and 42%) and are more frequently multiple (between 46.15% and 71%). Evidence shows that disease activity and active disease duration are influencing factors for the prevalence and incidence of VFs. Nonetheless, hypogonadism does not seem to influence the frequency of VFs. While reports are conflicting regarding the use of bone mineral density in acromegaly, evidence seems to be slightly in favor of it not being associated with VFs. However, trabecular bone score is significantly lower in fractured patients, although no prospective studies are available.

INTERPRETATION

Vertebral fractures evaluation should be performed with regularity in all acromegalic patients, especially in the presence of active disease. Disease activity is an important determinant of vertebral fracture incidence and prevalence, although hypogonadism is less so. To clarify the predictive value of both BMD and TBS for vertebral fractures, additional, larger, prospective studies are necessary.

The utility of dried blood spot measurement of bone turnover markers in biological anthropology

OBJECTIVES

Bone is a dynamic organ under continual turnover influenced by life history stage, energy dynamics, diet, climate, and disease. Bone turnover data have enormous potential in biological anthropology for testing evolutionary and biocultural hypotheses, yet few studies have integrated these biomarkers. In the present article we systematically review the current availability, future viability, and applicability of measuring bone turnover markers (BTMs) in dried blood spot (DBS) samples obtained from finger prick whole blood.

METHODS

Our review considers clinical and public health relevance, biomarker stability in DBS, assay availability, and cost. We consider biomarkers of bone formation such as osteocalcin (bone matrix protein), PINP (N-terminal propeptide of type I collagen), and alkaline phosphatase (osteoblast enzyme), as well as biomarkers of bone resorption such as CTX (marker of collagen breakdown) and TRACP5b (tartrate-resistant acid phosphatase 5b; osteoclast enzyme).

RESULTS

Two BTMs have been validated for DBS: osteocalcin (formation) and TRACP5b (resorption). Prime candidates for future development are CTX and PINP, the formation and resorption markers used for clinical monitoring of response to osteoporosis treatment.

CONCLUSION

BTMs are a field-friendly technique for longitudinal monitoring of skeletal biology during growth, reproduction and aging, combining minimized risk to study participants with maximized ease of sample storage and transport. This combination allows new insights into the effects of energy availability, disease, and physical activity level on bone, and questions about bone gain and loss across life history and in response to environmental factors; these issues are important in human biology, paleoanthropology, bioarchaeology, and forensic anthropology.

Downregulation of METTL14 improves postmenopausal osteoporosis via IGF2BP1 dependent posttranscriptional silencing of SMAD1

Osteoporosis (OP) tends to occur in postmenopausal women, making them prone to fractures. N6-methyladenosine (m6A) methylation plays a crucial role in OP. Herein, we aimed to explore the effects of METTL14 on osteogenesis and the underlying mechanism. Osteogenic differentiation was assessed through osteoblast markers expression, cell proliferation, ALP activity, and mineralization, which were detected by qRT-PCR, CCK-8, EdU assay, ALP staining assay, and ARS staining assay, respectively. Osteoporosis was evaluated in OVX mice using qRT-PCR, microcomputed tomography, and H&E staining assay. The levels of METTL14 and SMAD1 were measured using qRT-PCR and western blot, and their interaction was assessed using RIP and luciferase reporter assay. M6A methylation was analyzed using the Me-RIP assay. The results indicated that m6A, METTL14, and SMAD1 levels were downregulated in patients with OP and OVX mice, and upregulated in osteogenic BMSCs. Knockdown of METTL14 suppressed osteogenesis of BMSCs and reduced bone mass of OVX mice. Moreover, silencing of METTL14 positively related to SMAD1 and inhibited m6A modification of SMAD1 by suppressing its stability. IGF2BP1 was identified as the methylation reader, and which knockdown reversed the upregulation induced by SMAD1. Overexpression of SMAD1 reversed the suppression of osteogenic differentiation induced by METTL14 knockdown. In conclusion, interference with METTL14 inhibited osteogenic differentiation of BSMCs by m6A modification of SMAD1 in an IGFBP1 manner, suggesting that METTL14 might be a novel approach for improving osteoporosis.

The Impact of an Adapted Physical Activity Program on Bone Turnover, Physical Performance and Fear of Falling in Osteoporotic Women with Vertebral Fractures: A Quasi-Experimental Pilot Study

Physical activity has been indicated as a potential strategy to counteract osteoporosis (OP). This study of post-menopausal women with osteoporotic vertebral fractures investigated the effect of an adapted physical activity (APA) program on two serum bone turnover biomarkers (Bone Alkaline Phosphatase, B-ALP and C-terminal telopeptide of type 1 collagen, CTX-1), functional capacity (6-Minutes Walking Test, 6MWT), and risk and fear of falls (Tinetti and Falls Efficacy scale). The APA group (n = 12) performed a 1-h group session twice per week for 6 months whereas the control group (n = 9) was asked to maintain their current lifestyle. The exercise program did not affect the serum concentrations of B-ALP and CTX-1 biomarkers measured at the baseline and after 6 months in women of the APA group. Moreover, at the end of intervention no significant differences in serum concentrations for either biomarker was observed between the two study groups. Interestingly, when compared to the control group, women in the APA group showed significant improvement in the functional capacity measures by 6MWT (p = 0.037) and a decrease of the risk and fear of falls as indicated by the Tinetti test (p = 0.043). Based on these findings, exercise could provide new perspectives for the care and management of OP.

Effects of physical training on physical and functional fitness, physical activity level, endothelial function, hemodynamic variables, bone metabolism, and quality of life of post-bariatric patients: study protocol for a randomized controlled trial

BACKGROUND

Evidence of the benefits induced from resistance exercise on health markers of post-bariatric patients is limited. The study will investigate the effects of a resistance training (RT) program on muscle mass and strength, bone metabolism biomarkers, bone mineral density (BMD), bone microarchitecture, and endothelial function of patients subjected to Roux-en-Y gastric bypass.

METHODS/DESIGN

This randomized controlled trial will include 60 post-bariatric patients, physically inactive, aging 18 to 50 years, with a post-surgery period ≥ 12 months. They will be randomly assigned into two groups: (i) the non-exercised control group, which will receive the standard clinical follow-up, or (ii) the intervention group which will consist of RT (60 min/session; 3 times/week, for 6 months). The primary outcomes will include muscle mass and strength, bone metabolism biomarkers, BMD, and bone microarchitecture. The secondary outcomes will be anthropometry, hemodynamic measurements, cardiovascular risk factors, health-related quality of life (QoL), and endothelial function. Outcomes will be assessed by blood biomarkers of bone formation and reabsorption, dual X-ray absorptiometry, repetition maximum and handgrip strength tests, high-resolution peripheral quantitative computed tomography, 36-Item Short-Form Health Survey, venous occlusion plethysmography, and nailfold videocapillaroscopy.

DISCUSSION

It is expected that there are greater benefits from the RT program, possibly improving muscle mass and strength, bone metabolism, density and microarchitecture, QoL, and cardiovascular risk.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04193397. Registered on 7 December 2019.

A randomized, double-blind, placebo-controlled phase IIa trial of efruxifermin for patients with compensated NASH cirrhosis

Background & Aims

Efruxifermin has shown clinical efficacy in patients with non-alcoholic steatohepatitis (NASH) and F1-F3 fibrosis. The primary objective of the BALANCED Cohort C was to assess the safety and tolerability of efruxifermin in patients with compensated NASH cirrhosis.

Methods

Patients with NASH and stage 4 fibrosis (n = 30) were randomized 2:1 to receive efruxifermin 50 mg (n = 20) or placebo (n = 10) once-weekly for 16 weeks. The primary endpoint was safety and tolerability of efruxifermin. Secondary and exploratory endpoints included evaluation of non-invasive markers of liver injury and fibrosis, glucose and lipid metabolism, and changes in histology in a subset of patients who consented to end-of-study liver biopsy.

Results

Efruxifermin was safe and well-tolerated; most adverse events (AEs) were grade 1 (n = 7, 23.3%) or grade 2 (n = 19, 63.3%). The most frequent AEs were gastrointestinal, including transient, mild to moderate diarrhea, and/or nausea. Significant improvements were noted in key markers of liver injury (alanine aminotransferase) and glucose and lipid metabolism. Sixteen-week treatment with efruxifermin was associated with significant reductions in non-invasive markers of fibrosis including Pro-C3 (least squares mean change from baseline [LSMCFB] -9 μg/L efruxifermin vs. -3.4 μg/L placebo; p = 0.0130) and ELF score (-0.4 efruxifermin vs. +0.4 placebo; p = 0.0036), with a trend towards reduced liver stiffness (LSMCFB -5.7 kPa efruxifermin vs. -1.1 kPa placebo; n.s.). Of 12 efruxifermin-treated patients with liver biopsy after 16 weeks, 4 (33%) achieved fibrosis improvement of at least one stage without worsening of NASH, while an additional 3 (25%) achieved resolution of NASH, compared to 0 of 5 placebo-treated patients.

Conclusions

Efruxifermin appeared safe and well-tolerated with encouraging improvements in markers of liver injury, fibrosis, and glucose and lipid metabolism following 16 weeks of treatment, warranting confirmation in larger and longer term studies.

Lay summary

Cirrhosis resulting from non-alcoholic steatohepatitis (NASH), the progressive form of non-alcoholic fatty liver disease, represents a major unmet medical need. Currently there are no approved drugs for the treatment of NASH. This proof-of-concept randomized, double-blind clinical trial demonstrated the potential therapeutic benefit of efruxifermin treatment compared to placebo in patients with cirrhosis due to NASH.

Clinical Trial Number

NCT03976401.

Effects of ultra-low dose hormone therapy on biochemical bone turnover markers in postmenopausal women: A randomized, placebo-controlled, double-blind trial

Objective

Evaluate the effects of ultra-low-dose hormone therapy (Ultra-LD HT) with 17β-estradiol 0.5 mg and norethisterone acetate 0.1 mg (E2 0.5/NETA 0.1) versus placebo on bone turnover markers (BTM) in postmenopausal women.

Study Design

A multicenter, double-blind, randomized, placebo-controlled study was performed with 107 participants who received one tablet daily of E2 0.5/NETA 0.1 or placebo for 24-weeks. Bone formation markers-N-terminal propeptide of type I procollagen (PINP) and Bone-specific alkaline phosphatase (BSAP), and bone resorption markers-C-telopeptide of type I collagen (CTX-I) and N-telopeptide crosslinked of type I collagen (NTX) were assessed before and at 12 and 24-weeks of treatment.

Results

Women treated with E2 0.5/NETA 0.1 had a significant reduction in the PINP marker from baseline (58.49 ± 21.12 μg/L) to week 12 (48.31 ± 20.99 μg/L) and week 24 (39.16 ± 16.50 μg/L). Placebo group, the PINP marker did not differ significantly. The analysis of the BSAP indicated a significant increase in the placebo group (13.8 ± 5.09 μg/L and 16.29 ± 4.3 μg/L, at baseline and week 24, respectively), whereas in the treatment group the values did not change. The analysis of the NTX marker showed a significant reduction only in the treatment group (43.21 ± 15.26 nM/mM and 33.89 ± 14.9 nM/mM, at baseline and week 24, respectively). CTX-I had a significant decrease in the treatment group from baseline (0.3 ± 0.16 ng/L) to week 12 (0.21 ± 0.14 ng/L) and week 24 (0.21 ± 0.12 ng/L).

Conclusion

Women receiving E2 0.5/NETA 0.1 experienced reductions in bone resorption and formation markers, an expected effect during the anti-resorptive therapy, suggesting a protective bone effect with the Ultra-LD HT.

Collagen Turnover Biomarkers Associate with Active Psoriatic Arthritis and Decrease with Guselkumab Treatment in a Phase 3 Clinical Trial (DISCOVER-2)

INTRODUCTION

Guselkumab, a novel interleukin-23p19 subunit monoclonal antibody, has been shown to effectively improve the diverse manifestations of active psoriatic arthritis (PsA) in two phase 3 trials (DISCOVER-1, DISCOVER-2). Serum concentrations of extracellular matrix (ECM) biomarkers at baseline and following treatment with guselkumab were evaluated in patients with active PsA, and the relationship of these biomarkers with baseline PsA characteristics and clinical response to guselkumab treatment was explored.

METHODS

Serum samples were collected at weeks 0, 4, 24, and 52 from a selected subset (N = 260) of the 739 biologic-naïve patients with PsA treated with guselkumab 100 mg every 4 or 8 weeks or placebo in DISCOVER-2. Demographically matched healthy controls (N = 76) were used for comparison. The samples were analyzed for ECM biomarkers associated with collagen degradation (C1M, C2M, C3M, C4M, C6M, C10C) and collagen formation (PRO-C1, PRO-C2, PRO-C3, PRO-C4, PRO-C6).

RESULTS

Baseline concentrations of collagen degradation biomarkers C1M, C3M, C4M, and C6M and collagen formation biomarkers PRO-C3 and PRO-C6 were significantly higher (i.e., ≥ 1.25-fold and false discovery rate adjusted p < 0.05) in PsA patients than in healthy controls. Serum C1M, C3M, C4M, and C6M levels declined from baseline in guselkumab-treated patients in both dosing regimens. In addition, guselkumab-treated ACR20 responders (≥ 20% improvement in American College of Rhematology response criteria) had significantly lower C1M levels than ACR20 nonresponders.

CONCLUSION

These data demonstrate that serum collagen biomarkers are elevated in patients with PsA compared with healthy controls and that treatment with guselkumab decreases levels of C1M, C3M, C4M, and C6M. Importantly, C1M serves as a biomarker that associates with improvement of joint signs and symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03158285.

The effect of Cissus quadrangularis L. on delaying bone loss in postmenopausal women with osteopenia: A randomized placebo-controlled trial

BACKGROUND

Osteopenia refers to bone density that is not normal but also not as low as that noted in osteoporosis. Osteopenia leads to osteoporosis and increases the risk of fractures. Current research is focused on agents that will prevent or slow the progression of bone loss. On the basis of published evidence, Cissus quadrangularis (CQ) might potentially provide a novel natural treatment for osteopenia.

PURPOSE

To determine the effect of 24 weeks of consecutive treatment with CQ on delaying bone loss and safety in postmenopausal women (PMW) with osteopenia.

METHODS

This study is a randomized, placebo-controlled trial. Here, 134 enrolled PMW with osteopenia (> 40 years and having no period for 1-10 years) received CQ at 1.2 (CQ1.2) or 1.6 g/day (CQ1.6) or placebo. The %change in bone mineral density (BMD) at the lumbar spine (L1-L4), femoral neck, and total hip served as the primary outcome. The %change in bone turnover markers (BTMs), including C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 amino-terminal propeptide (P1NP), was the secondary outcome. These outcomes were compared between the CQ vs. placebo group at weeks 12 and 24. The least significant change (LSC) was used to monitor clinical changes. The adverse events (AE) were monitored.

RESULTS

A total of 108 participants completed this study. The %BMD changes in the CQ-treated groups did not differ at any site after 24 weeks compared to the placebo. Statistically significant differences were detected in CQ1.6 at the lumbar spine (0.011 ± 0.025 g/cm², p = 0.008) and CQ1.2 at the femoral neck (-0.015 ± 0.036 g/cm², p = 0.024) compared to baseline, but these changes did not exceed the LSC. Reduced bone remodeling activity was detected in both CQ-treated groups. Compared to the placebo, the %P1NP change was significantly reduced in CQ1.6 (-2.46 ± 26.05%; p < 0.01) at week 12 and in CQ1.2 (-3.36 ± 29.47%; p < 0.01) and CQ1.6 (-9.95 ± 22.22%; p < 0.01) at week 24. These results correlated with the within-group comparison, which showed a continuously significant increase in both BTMs in the placebo group. However, a stable CTX and a significant reduction in P1NP (p < 0.05) were detected in both CQ-treated groups. This reduction exceeded the LSC of P1NP. The incidence of adverse events did not differ among the three groups.

CONCLUSION

This is the first clinical report that showed a promising effect on delaying bone loss of orally administration of CQ for 24 weeks, as indicated by a slower bone remodeling process via a reduction in BTMs. However, no change in BMD was observed.

Association between bone turnover markers and periodontitis: A population-based cross-sectional study

AIM

To examine the associations between bone turnover markers and periodontitis in two cross-sectional population-based studies.

MATERIALS AND METHODS

We used data from two independent adult samples (N = 4993), collected within the Study of Health in Pomerania project, to analyse cross-sectional associations of N-procollagen type 1 amino-terminal propeptide (P1NP), C-terminal cross-linking telopeptide, osteocalcin, bone-specific alkaline phosphatase (BAP), fibroblast growth factor 23, wingless-type mouse mammary tumour virus integration site family member 5a (WNT5A), and sclerostin values with periodontitis. Confounder-adjusted gamma and fractional response regression models were applied.

RESULTS

Positive associations were found for P1NP with mean pocket probing depth (PPD; e β = 1.008 ; 95% confidence interval [CI]: 1.001-1.015), mean clinical attachment loss (mean CAL; e β = 1.027 ; 95% CI: 1.011-1.044), and proportion of sites with bleeding on probing (%BOP; e β = 1.055 ; 95% CI: 1.005-1.109). Similar associations were seen for BAP with %BOP ( e β = 1.121 ; 95% CI: 1.042-1.205), proportion of sites with PPD ≥4 mm (%PPD4) ( e β = 1.080 ; 95% CI: 1.005-1.161), and sclerostin with %BOP ( e β = 1.308 ; 95% CI: 1.005-1.704). WNT5A was inversely associated with mean PPD ( e β = 0.956 ; 95% CI: 0.920-0.993) and %PPD4 ( e β = 0.794 ; 95% CI: 0.642-0.982).

CONCLUSIONS

This study revealed scattered associations of P1NP, BAP, WNT5A, and sclerostin with periodontitis, but the results are contradictory in the overall context. Associations reported in previous studies could not be confirmed.

The clinical utility of TRACP-5b to monitor anti-resorptive treatments of osteoporosis

TRACP-5b can be used to monitor the response of treatments in osteoporosis. We investigated the effect of feeding on levels of TRACP-5b and how these markers perform in a clinical setting. After feeding, there was no effect on levels TRACP-5b. It has similar diagnostic accuracy to CTX and PINP.

INTRODUCTION

Bone turnover markers (BTMs) can be used to monitor response to osteoporosis treatment. However, some are affected by food intake and are not suitable to measure in a clinical setting. An assay is available which is capable of detecting the active isoform 5b of tartrate resistance acid phosphatase (TRACP-5b) and it may have minimal biological variation. Our aims were to investigate the effect of feeding on levels of TRACP-5b and compare this to CTX and PINP and then to compare the diagnostic accuracy of TRACP-5b to CTX and PINP in patients with osteoporosis given commonly used treatments.

METHODS

Eighteen patients were recruited to investigate the effect of feeding on BTMs. Ninety-seven patients (74 females and 23 males) receiving 5 mg annual intra-venous zoledronate (mean age 70) and 97 patients receiving no treatment were recruited as group-matched controls. Sixteen patients receiving 60 mg subcutaneous denosumab every 6 months, (mean age 76) and 16 matched controls were recruited. Seventy-six patients were receiving oral bisphosphonates: 70 mg alendronate weekly, 35 mg risedronate and 150 mg monthly ibandronate (4%). Thirty of these patients had BMD measured at the total hip and lumbar spine. An estimate of compliance was not determined. Eighty patients receiving no treatment were recruited as group-matched controls. TRACP-5b (ELISA, Nittobo) and CTX and PINP were measured in serum in the non-fasting state between 0800 and 1700.

RESULTS

After feeding, there was no effect on levels TRACP-5b and significant reductions in CTX and PINP, 29% and 10%, respectively (p < 0.001). In the zoledronate and denosumab groups, there were no differences in the areas under the curves (AUCs) between TRACP-5b, PINP and CTX. In the oral bisphosphonates group, the AUCs between TRACP-5b and PINP and TRACP-5b and CTX were significantly different, p < 0.01 and p = 0.001, respectively. TRACP-5b was negatively correlated with BMD.

CONCLUSION

TRACP-5b is not affected by food intake, unlike CTX and PINP. All three BTMs correlate with change in BMD at the lumbar spine and total hip. TRACP-5b has similar diagnostic accuracy to CTX and PINP with commonly used treatments for osteoporosis with the exception of oral bisphosphonate therapy.

Prevalence of Vertebral Fractures in Adults With Type 1 Diabetes: DenSiFy Study (Diabetes Spine Fractures)

CONTEXT

Vertebral fracture (VF) prevalence up to 24% has been reported among young people with type 1 diabetes (T1D). If this high prevalence is confirmed, individuals with T1D could benefit from preventative VF screening.

OBJECTIVE

We compared the prevalence of VFs between adults with T1D and nondiabetic controls.

METHODS

This cross-sectional study included 127 adults with T1D, and 65 controls with a similar age, sex, and BMI distribution, from outpatient clinics of 2 tertiary care centers. Vertebral fracture assessment (VFA) by dual-energy x-ray absorptiometry (DXA) was used for prevalent VFs. The modified algorithm-based qualitative (mABQ) method was applied. Bone mineral density (BMD) and trabecular bone score (TBS) were assessed by DXA. Serum bone turnover markers and sclerostin were measured in a subgroup of participants.

RESULTS

Participants with T1D (70 women, 57 men) had a mean age of 42.8 ± 14.8 years, median diabetes duration of 25.8 (15.8-34.4) years, mean BMI of 26.6 ± 5.4 kg/m2 and mean HbA1c over the past 3 years of 7.5 ± 0.9%. Controls (35 women, 30 men) had mean age of 42.2 ± 15.9 years and mean BMI of 26.1 ± 5.1 kg/m2. VF prevalence was comparable between groups (2.4% vs 3.1%, P = 0.99). TBS, BMD at the total hip and femoral neck, and bone formation and resorption markers were lower while sclerostin levels were similar in participants with T1D vs controls.

CONCLUSION

Our VFA results using the mABQ method do not confirm increased prevalence of VFs in men and women with relatively well-controlled T1D.

Tanshinone Ameliorates Glucocorticoid-Induced Bone Loss via Activation of AKT1 Signaling Pathway

Purpose: Osteoporosis, a common disorder especially prevalent in the postmenopausal women and the elderly, is becoming a worldwide public health problem. Osteoporosis can cause severe joint pain, fragility fractures, and other symptoms, which can seriously impair the daily lives of affected patients. Currently, no gold-standard drug is available that can completely cure osteoporosis. Tanshinone is a traditional Chinese medicine, which can exhibit multiple biological activities. It might also display a protective effect on osteoporosis. However, the molecular mechanism through which tanshinone can improve osteoporosis remain unclear. The objective of our study is to explore the underlying mechanism behind the protective actions of tanshinone. Methods: The common KEGG pathways of tanshinone-targeted genes and osteoporosis were analyzed by using bioinformatics analysis. The bioinformatics analysis results were further validated both by in vitro and in vivo experiments. Results: 21 common KEGG pathways were identified between osteoporosis and tanshinone-targeted genes. It was further found that tanshinone could induce expression of AKT1, promote the proliferation of MSCs, and ultimately suppress their apoptosis. Conclusion: Taken together, our findings indicate that tanshinone can alleviate osteoporosis, its effect was potentially mediated through modulating AKT1 expression. Thus, tanshinone could serve as a promising treatment option for osteoporosis.

Vitamin D Supplementation for 12 Months in Older Adults Alters Regulators of Bone Metabolism but Does Not Change Wnt Signaling Pathway Markers

Vitamin D status and supplementation regulates bone metabolism and may modulate Wnt signaling. We studied the response of hormonal regulators of bone metabolism, markers of Wnt signaling and bone turnover and bone mineral density (BMD) and bone mineral content (BMC) in a randomized vitamin D intervention trial (12,000 IU, 24,000 IU, 48,000 IU/mo for 1 year; men and women aged >70 years; n = 379; ISRCTN35648481). Associations with total and free 25(OH)D concentrations were analyzed by linear regression. Baseline vitamin D status was (mean ± SD) 25(OH)D: 40.0 ± 20.1 nmol/L. Supplementation dose-dependently increased total and free 25(OH)D concentrations and decreased plasma phosphate and parathyroid hormone (PTH) (all p < 0.05). The procollagen 1 intact N-terminal (PINP)/C-terminal telopeptide (CTX) ratio, C-terminal fibroblast growth factor-23 (cFGF23), and intact FGF23 (iFGF23) significantly increased with no between-group differences, whereas Klotho was unchanged. 1,25(OH)₂D and PINP significantly increased in the 24 IU and 48,000 IU groups. Sclerostin (SOST), osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL), BMD, BMC, and CTX remained unchanged. Subgroup analyses with baseline 25(OH)D <25 nmol/L (n = 94) provided similar results. Baseline total and free 25(OH)D concentrations were positively associated with 1,25(OH)₂D, 24,25(OH)₂D (p < 0.001), vitamin D binding protein (DBP) (p < 0.05), BMD, and BMC (p < 0.05). Associations with PTH (p <0.001), cFGF23 (p < 0.01), and BAP (p < 0.05) were negative. After supplementation, total and free 25(OH)D concentrations remained positively associated only with 24,25(OH)₂D (p < 0.001) and DBP (p < 0.001) and negatively with estimated glomerular filtration rate (eGFR) (p < 0.01). PTH and SOST were significantly associated only with free 25(OH)D. There were no significant relationships with BMD and BMC after supplementation. The decrease in PTH and increase in PINP/CTX ratio suggest a protective effect of supplementation on bone metabolism, although no significant effect on BMD or pronounced changes in regulators of Wnt signaling were found. The increase in FGF23 warrants caution because of its negative association with skeletal and cardiovascular health. Associations of total and free 25(OH)D with biomarkers were similar and known positive associations between vitamin D status and BMD were confirmed. The change in associations after supplementation might suggest a threshold effect. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.