Advances in bone turnover markers

Long-term effects of s-KL treatment in wild-type mice: Enhancing longevity, physical well-being, and neurological resilience

Aging is a major risk factor for pathologies including sarcopenia, osteoporosis, and cognitive decline, which bring suffering, disability, and elevated economic and social costs. Therefore, new therapies are needed to achieve healthy aging. The protein Klotho (KL) has emerged as a promising anti-aging molecule due to its pleiotropic actions modulating insulin, insulin-like growth factor-1, and Wnt signaling pathways and reducing inflammatory and oxidative stress. Here, we explored the anti-aging potential of the secreted isoform of this protein on the non-pathological aging progression of wild-type mice. The delivery of an adeno-associated virus serotype 9 (AAV9) coding for secreted KL (s-KL) efficiently increased the concentration of s-KL in serum, resulting in a 20% increase in lifespan. Notably, KL treatment improved physical fitness, related to a reduction in muscle fibrosis and an increase in muscular regenerative capacity. KL treatment also improved bone microstructural parameters associated with osteoporosis. Finally, s-KL-treated mice exhibited increased cellular markers of adult neurogenesis and immune response, with transcriptomic analysis revealing induced phagocytosis and immune cell activity in the aged hippocampus. These results show the potential of elevating s-KL expression to simultaneously reduce the age-associated degeneration in multiple organs, increasing both life and health span.

Characterization of Trivalently Crosslinked C-Terminal Telopeptide of Type I Collagen (CTX) Species in Human Plasma and Serum Using High-Resolution Mass Spectrometry

With an aging population, the increased interest in the monitoring of skeletal diseases such as osteoporosis led to significant progress in the discovery and measurement of bone turnover biomarkers since the 2000s. Multiple markers derived from type I collagen, such as CTX, NTX, PINP, and ICTP, have been developed. Extensive efforts have been devoted to characterizing these molecules; however, their complex crosslinked structures have posed significant analytical challenges, and to date, these biomarkers remain poorly characterized. Previous attempts at characterization involved gel-based separation methods and MALDI-TOF analysis on collagen peptides directly extracted from bone. However, using bone powder, which is rich in collagen, does not represent the true structure of the peptides in the biofluids as it was cleaved. In this study, our goal was to characterize plasma and serum CTX for subsequent LC-MS/MS method development. We extracted and characterized type I collagen peptides directly from human plasma and serum using a proteomics workflow that integrates preparative LC, affinity chromatography, and HR-MS. Subsequently, we successfully identified numerous CTX species, providing valuable insights into the characterization of these crucial biomarkers.

Effects of key physiological parameters on cardiovascular disease and osteoporosis risk in perimenopausal and postmenopausal women

The essential cause of menopause is ovarian failure, which can cause decline in sex hormones (especially estrogen) that can increase the risk of metabolic diseases, such as cardiovascular disease and osteoporosis. This study screened 1511 eligible patients from 2148 perimenopausal and postmenopausal women, measuring various physiological and biochemical indicators to analyze differences among age groups (40-44, 45-49, and 50-54 years) with laboratory techniques. The study found no significant difference in the incidence of cardiovascular disease betweenperimenopausal and postmenopausal women. But the incidence of osteoporosis was higher in postmenopausal women and was associated with age (p < 0.05). Additionally, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), total cholesterol (TC), lumbar spine bone mineral density (BMD) (T1), right femoral BMD (T2) and femoral neck BMD were significantly correlated in both groups. Significant differences were observed in FSH, LH, E2, TC, low-density lipoprotein (LDL), L2-L4, T1, femoral neck reduction and T2 among women in different age groups. Correlation analysis indicated that age increased the risk of cardiovascular disease and osteoporosis in bothperimenopausal and postmenopausal women. This study contributes to a deeper understanding of the pathogenesis of cardiovascular disease and osteoporosis in perimenopausal and menopausal women.

Hormonal Contraception and Bone Metabolism: Emerging Evidence from a Systematic Review and Meta-Analysis of Studies on Post-Pubertal and Reproductive-Age Women

BACKGROUND/OBJECTIVES

This study aims to assess the effects of combined hormonal contraceptives (CHCs) on bone metabolism markers. It primarily measures osteocalcin and additionally examines other bone health markers, seeking to determine their responses to estrogen-progestogen treatments.

METHODS

This study involved a comprehensive evaluation of the pertinent literature and a meta-analysis explicitly conducted on data describing women of reproductive age. The analysis encompassed accessible papers ranging to December 2024 (i.e., those listed in PubMed/Medline, Embase, Scopus, the Cochrane Database, International Clinical Trials Registry, and ClinicalTrials.gov). We examined published randomized controlled trials (RCTs) and prospective studies. The quality of the studies was assessed using the Cochrane tool for RCTs and the Newcastle-Ottawa Scale for prospective studies. The selected indicators for primary and secondary outcomes were ascertained by standardized mean change (SMC), displaying the difference between conditions before and after treatment. Trends were evaluated using meta-regressions.

RESULTS

Ultimately, 34 articles out of 1924 identified items met the inclusion criteria, covering 33 unique studies. In EE/E4 combinations, osteocalcin dropped significantly (SMC -0.54 (CI.95 -0.64/-0.43) and -0.43 (CI.95 -0.76/-0.10)). Similar effects were observed for other bone-formation and reabsorption markers, with less significant reductions observed in E2-containing CHC (e.g., alkaline phosphatase (bone) EE combinations, SMC -0.39 (CI.95 -0.67/-0.11); P1NP E2 combination, 0.12 (CI.95 -0.10/0.33); and EE combinations, -0.55 (CI.95 -0.83/-0.26)). The reduction patterns also exhibited differences according to the women's age (e.g., osteocalcin in EE combinations ≤21, SMC -0.63 (CI.95 -0.77/-0.49) and >21, SMC -0.42 (CI.95 -0.61/-0.24); alkaline phosphatase (bone) EE combinations ≤21, SMC -0.55 (CI.95 -0.86/-0.24) and >21, SMC -0.06 (CI.95 -0.47/0.35)). This analysis found that CHC maintains or reduces bone turnover in childbearing women, with effects varying by age and hormone combination. Moreover, bone-formation and reabsorption markers correlated positively to pro-androgenic progestins (p < 0.05). Thus, estrogen-progestogen combinations reduce bone turnover less when weak estrogens and a pro-androgenic or neutral progestin are present.

CONCLUSIONS

This study found that CHCs reduce bone turnover, with natural estrogens and androgenic progestins appearing to be more beneficial than EE and anti-androgenic types. These findings would potentially influence decisions relevant to CHC prescriptions during a woman's reproductive phases, emphasizing the need for additional research to tailor CHC usage to bone health.

IGF-1 c.258 A > G synonymous mutation ameliorates senile osteoporosis

Senile osteoporosis (SOP) is a multifactorial, age-related progressive phenomenon with a considerable morbidity and mortality. IGF-1 is an important regulator of bone reconstruction and metabolism throughout life. Nevertheless, our previous study unexpectedly found there is no change in the peak bone mass with a altered IGF-1 gene expression leaded by IGF-1 c.258 A > G synonymous mutation. Considering its involvement in the cellular senescence, we suspected c.258 A > G may participate in SOP. Therefore, the effect of IGF-1 c.258 A > G on SOP was firstly detected, the changes of bone formation and bone resorption index in SOP mice with two genotypes indicated it improved SOP. Then, the in vitro study confirmed the mutation ameliorates SOP by promoting the growth and development of senescent osteoblasts. At last, co-culture of osteoblast and osteoclast further verified the mutation prevents SOP by increasing the bone formation capacity of senescent osteoblasts. Collectively, this study illuminated the role of IGF-1 c.258 A > G in ameliorating SOP.

Association of Changes in Relevant Indicators With Cardiovascular Disease and Osteoporosis in Perimenopausal and Postmenopausal Women

The essence of menopause is ovarian failure, decreased estrogen volatility, and deficiency leading to multiple related symptoms and an increased risk of metabolic disease in women, such as cardiovascular disease and osteoporosis. This study screened 773 eligible postmenopausal and perimenopausal women from an initial pool of 1187 participants, and various physiological and biochemical indices were measured and analyzed to assess differences across three age groups (40-44 years, 45-49 years, 50-54). We found no significant difference in the rate of cardiovascular disease between postmenopausal and perimenopausal women, while the rate of osteoporosis was higher in postmenopausal women compared to perimenopausal women. The disease of osteoporosis in postmenopausal women was associated with age (p < 0.05). We also found that postmenopausal women and perimenopausal women had significant effects on follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), total cholesterol (TC), lumbar spine BMD (T1), femoral neck BMD, The bone density (T2) of the right femur was significantly affected. There are significant differences in FSH, LH, E2, TC, low-density lipoprotein (LDL), L2-L4, T1, Neck of femur decrease, and T2 in women of different ages. Furthermore, the correlation analysis between age and E2 and metabolic indicators showed that age has a greater impact on the risk of postmenopausal and perimenopausal females. This study can help further understand the mechanisms of cardiovascular disease and osteoporosis in perimenopausal and menopausal women.

The influence of radiation-induced collagen chain fragmentation, crosslinking, and sequential irradiation on the high-cycle fatigue life of human cortical bone

Both high-cycle fatigue life and fatigue crack propagation resistance of human cortical bone allograft are radiation dose-dependent between 0 and 25 kGy such that higher doses exhibit progressively shorter lifetimes. Recently, we have shown that collagen chain fragmentation and stable crosslink accumulation may contribute to the radiation dose-dependent loss in fatigue crack propagation resistance of human cortical bone. To our knowledge, the influence of these mechanisms on high-cycle fatigue life of cortical bone have not been established. Sequential irradiation has also been shown to mitigate the loss of fatigue life of tendons, however, whether this mitigates losses in fatigue life of cortical bone has not been explored. Our objectives were to evaluate the influence of radiation-induced collagen chain fragmentation and crosslinking on the high-cycle fatigue life of cortical bone in the dose range of 0-15 kGy, and to evaluate the capability of sequential irradiation at 15 kGy to mitigate the loss of high-cycle fatigue life and radiation-induced collagen damage. High-cycle fatigue life specimens from four male donor femoral pairs were divided into 5 treatment groups (0 kGy, 5 kGy, 10 kGy, 15 kGy, and 15 kGy sequentially irradiated) and subjected to high-cycle fatigue life testing with a custom rotating-bending apparatus at a cyclic stress of 35 MPa. Following fatigue testing, collagen was isolated from fatigue specimens, and collagen chain fragmentation and crosslink accumulation were quantified using SDS-PAGE and a fluorometric assay, respectively. Both collagen chain fragmentation (p = 0.006) and non-enzymatic crosslinking (p < 0.001) influenced high-cycle fatigue life, which decreased with increasing radiation dose from 0 to 15 kGy (p = 0.016). Sequential irradiation at 15 kGy did not offer any mitigation in high-cycle fatigue life (p = 0.93), collagen chain fragmentation (p = 0.99), or non-enzymatic crosslinking (p ≥ 0.10) compared to a single radiation dose of 15 kGy. Taken together with our previous findings on the influence of collagen damage on fatigue crack propagation resistance, collagen chain fragmentation and crosslink accumulation both contribute to radiation-induced losses in notched and unnotched fatigue life of cortical bone. To maximize the functional lifetime of radiation sterilized structural cortical bone allografts, pathways other than sequential radiation should be explored to mitigate collagen matrix damage.

Butea monosperma bark extract: a natural boost for osteogenesis via Wnt/β-catenin pathway activation in adipose-derived mesenchymal stem cells

PURPOSE

To investigate the impact of Butea monosperma (BM) bark extract on the osteogenic differentiation potential of rat adipose-derived mesenchymal stem cells (rADMSCs) and to elucidate the involvement of Wnt/β-catenin pathway in mediating this osseous effect.

METHODS

Characterizations (antioxidant assays, FTIR and LC/MS analyses) and docking studies (in silico) were performed to evaluate the presence of phytochemicals in the BM extract and their binding capacity to that of the frizzled receptor. rADMSCs were isolated and characterised for its differentiation potential of osteogenesis for stemness. Dose fixation, cytotoxicity, osteogenic differentiation (calcium, mineral deposition, alkaline phosphatase and osteocalcin) and gene expression (osteocalcin, Col1, osteonectin, Bmp2, Runx2, Wnt2, and β-catenin-14 and 28 days) of the extract were also evaluated in vitro.

RESULTS

FTIR and LC/MS analyses unveiled the phytochemicals in the extract and with docking studies confirmed their interaction with the frizzled receptor of Wnt/β-catenin pathway. rADMSCs were isolated and differentiated in the presence of the osteogenic induction medium. Dose fixation studies, cytotoxicity and cell viability assessments demonstrated the phytochemicals concentration-dependent cytotoxicity. The presence of specific bone markers highlighted the osteogenic differentiation potential of the phytochemicals. Furthermore, gene expression studies of rADMSCs depicted a heightened bone-forming capacity potentially facilitated by the activation of Wnt/β-catenin pathway.

CONCLUSION

 The phytochemicals of BM promoted the osteogenic differentiation of rADMSCs through the activation of the signalling Wnt/β-Catenin pathway, as evidenced by the significant upregulation of early and late bone markers. The phytochemicals may therefore be positioned as promising therapeutic agents for enhancing bone regeneration, offering new avenues for regenerative medicine.

Titanium micro-nano textured surface with strontium incorporation improves osseointegration: an in vivo and in vitro study

OBJECTIVES

This study aimed to investigate the osseointegration of titanium (Ti) implants with micro-nano textured surfaces functionalized with strontium additions (Sr) in a pre-clinical rat tibia model.

METHODOLOGY

Ti commercially pure (cp-Ti) implants were installed bilaterally in the tibia of 64 Holtzman rats, divided into four experimental groups (n=16/group): (1) Machined surface - control (C); (2) Micro-nano textured surface treatment (MN); (3) Micro-nano textured surface with Sr2+ addition (MNSr); and (4) Micro-nano textured surface with a higher complementary addition of Sr2+ (MNSr+). In total, two experimental euthanasia periods were assessed at 15 and 45 days (n=8/period). The tibia was subjected to micro-computed tomography (μ-CT), histomorphometry with the EXAKT system, removal torque (TR) testing, and gene expression analysis by PCR-Array of 84 osteogenic markers. Gene expression and protein production of bone markers were performed in an in vitro model with MC3T3-E1 cells. The surface characteristics of the implants were evaluated by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and laser scanning confocal microscopy.

RESULTS

SEM, confocal, and EDS analyses demonstrated the formation of uniform micro-nano textured surfaces in the MN group and Sr addition in the MNSr and MNSr+ groups. TR test indicated greater osseointegration in the 45-day period for treated surfaces. Histological analysis highlighted the benefits of the treatments, especially in cortical bone, in which an increase in bone-implant contact was found in groups MN (15 days) and MNSr (45 days) compared to the control group. Gene expression analysis of osteogenic activity markers showed modulation of various osteogenesis-related genes. According to the in vitro model, RT-qPCR and ELISA demonstrated that the treatments favored gene expression and production of osteoblastic differentiation markers.

CONCLUSIONS

Micro-nano textured surface and Sr addition can effectively improve and accelerate implant osseointegration and is, therefore, an attractive approach to modifying titanium implant surfaces with significant potential in clinical practice.

Dose-dependent effects of gamma radiation sterilization on the collagen matrix of human cortical bone allograft and its influence on fatigue crack propagation resistance

Fatigue crack propagation resistance and high-cycle S-N fatigue life of cortical bone allograft tissue are both negatively impacted in a radiation dose-dependent manner from 0 to 25 kGy. The standard radiation sterilization dose of 25-35 kGy has been shown to induce cleavage of collagen molecules into smaller peptides and accumulation of stable crosslinks within the collagen matrix, suggesting that these mechanisms may influence radiation-induced losses in cyclic fracture resistance. The objective of this study was to determine the radiation dose-dependency of collagen chain fragmentation and crosslink accumulation within the dose range of 0-25 kGy. Previously, cortical bone compact tension specimens from two donor femoral pairs were divided into four treatment groups (0 kGy, 10 kGy, 17.5 kGy, and 25 kGy) and underwent cyclic loading fatigue crack propagation testing. Following fatigue testing, collagen was isolated from one compact tension specimen in each treatment group from both donors. Radiation-induced collagen chain fragmentation was assessed using SDS-PAGE (n = 5), and accumulation of pentosidine, pyridinoline, and non-specific advanced glycation end products were assessed using a fluorometric assay (n = 4). Collagen chain fragmentation increased progressively in a dose-dependent manner (p < 0.001). Crosslink accumulation at all radiation dose levels increased relative to the 0 kGy control but did not demonstrate dose-dependency (p < 0.001). Taken together with our previous findings on fatigue crack propagation behavior, these data suggest that while collagen crosslink accumulation may contribute to reduced notched fatigue behavior with irradiation, dose-dependent losses in fatigue crack propagation resistance are mainly influenced by radiation-induced chain fragmentation.

Cedrol alleviates postmenopausal osteoporosis in rats through inhibiting the activation of the NF-κB signaling pathway

Pharmacological studies have shown that Cedrol (CE) exhibits extensive biological activities, including anti-inflammatory and analgesic. Moreover, it can inhibit the NF-κB pathway and the expression of various associated proteins. This study aimed to investigate the role of CE in postmenopausal osteoporosis. The results showed that intragastric administration of CE (10 and 20 mg/kg) significantly improved the bone microstructure damage and increased bone mineral density, trabecular bone volume, and bone trabecular thickness in ovariectomized (OVX) rats (p < 0.05). CE treatment additionally made a well-organized arrangement of bone trabeculae and improved its thickness and density. Compared with the OVX group, the levels of tartrate-resistant acid phosphatase from 5b and C-terminal telopeptide of type I collagen were significantly reduced by 42.75% and 49.27% in the OVX + CE rats (p < 0.05). TRAP staining visually showed that the number of osteoclasts in the femur tissue of CE-treated rats was less than that of the OVX group. The expressions of nuclear factor of activated T-cells, cytoplasmic 1, acid phosphatase 5, and cathepsin K in OVX + CE rats were significantly decreased by 51.61%, 46.07%, and 50.34% compared to the OVX group (p < 0.01). In addition, CE intervention effectively reduced the phosphorylation levels of P65 and IκBα and inhibited the NF-κB signaling pathway. Meanwhile, CE diminished the number of multinucleated osteoclasts induced by receptor activator for nuclear factor-κB ligand and hindered cell fusion as well as nuclear translocation of osteoclast precursor cells P65. In conclusion, CE inhibits osteoclastogenesis by suppressing the activation of the NF-κB signaling pathway, thereby alleviating postmenopausal osteoporosis.

The microalga Volvox carteri as a cell supportive building block for tissue engineering

Background

V. carteri f. nagariensis constitutes, in its most simplified form, a cellularized spheroid built around and stabilised by a form of primitive extracellular matrix (ECM).

Methods

We developed a modular approach to soft tissue engineering, by compact stacking V. carteri-based building blocks. This approach is made possible by the structure and cell adhesive properties of these building blocks, which results from the composition of their algal ECM.

Results

A primary biocompatibility assessment demonstrated the cytocompatibility of the algal suspension, its histogenesis-promoting properties, and that it did not induce an inflammatory response in vitro. These results allowed us to consider the use of this algal suspension for soft tissue augmentation, and to initiate an in vivo biocompatibility study. V. carteri exhibited cellular fate-directing properties, causing (i) fibroblasts to take on an alkaline phosphatase+ stem-cell-like phenotype and (ii) both human adipose-derived stem cells and mouse embryonic stem cells to differentiate into preadipocytes to adipocytes. The ability of V. carteri to support histogenesis and adipogenesis was also observed in vivo by subcutaneous tissue augmentation of athymic mice, highlighting the potential of V. carteri to support or influence tissue regeneration.

Conclusions

We present for the first time V. carteri as an innovative and inspiring biomaterial for tissue engineering and soft tissue regeneration. Its strategies in terms of shape, structure and composition can be central in the design of a new generation of bio-inspired heterogeneous biomaterials recapitulating more appropriately the complexity of body tissues when guiding their regeneration.

Efficient three-dimensional (3D) human bone differentiation on quercetin-functionalized isotropic nano-architecture chitinous patterns of cockroach wings

Developing cost-effective, biocompatible scaffolds with nano-structured surface that truthfully replicate the physico-(bio)chemical and structural properties of bone tissue's extracellular matrix (ECM) is still challenging. In this regard, surface functionalization of natural scaffolds to enhance capability of mimicking 3D niches of the bone tissue has been suggested as a solution. In the current study, we aimed to investigate the potential of chitin-based cockroach wings (CW) as a natural scaffold for bone tissue engineering. To raise the osteogenic differentiation capacity of such a scaffold, a quercetin coating was also applied (hereafter this scaffold is referred as QCW). Moreover, the QCW scaffold exhibited effective antibacterial properties against gram-positive S. aureus bacteria. With respect to bone regeneration, the QCW scaffold optimally induced the differentiation of adipose-derived human mesenchymal stem cells (AD-hMSCs) into osteoblasts, as validated by mineralization assays, alkaline phosphatase (ALP) activity measurements, expression of pre-osteocyte marker genes, and immunocytochemical staining. Confirmation of the potent biocompatibility and physicochemical characteristics of the QCW scaffold through a series of in vitro and in vivo analysis revealed that surface modification had significant effect on multi-purpose features of obtained scaffold. Altogether, surface modification of QCW made it as an affordable bioinspired scaffold for bone tissue engineering.

Correlation between bone mineral density and bone metabolic markers in postmenopausal women with osteoporotic fractures at different C-terminal telopeptide of type 1 collagen levels: a retrospective analysis study

OBJECTIVE

This study aimed to analyze the correlation between bone mineral density (BMD) and bone resorption markers in postmenopausal women with osteoporosis fractures and identify risk factors for second fractures.

METHODS

This retrospective analysis of 1,239 older women with fractures with a median age of 70 years who attended Shanghai General Hospital from January 2007 to December 2016, included a first fracture group (1,008 cases) and a second fractures group (231 cases). The risk factors for fractures were analyzed by comparing these groups on clinical characteristics, BMD, and bone metabolism markers stratified by quartiles of serum C-terminal telopeptide of type 1 collagen (CTX). Binary logistic regression analysis was used to identify risk factors for second fractures.

RESULTS

In the whole sample, BMD was negatively correlated with age and serum osteocalcin and positively correlated with body mass index (BMI). In women with first fractures, those in the highest quartile of serum CTX had the lowest spine and hip BMD. Second fractures were significantly associated with BMI, lower spine and hip BMD, and higher serum osteocalcin but not CTX. Binary logistic regression analysis showed that high BMI (odds ratio [OR], 1.08 [95% CI, 1.03-1.14]; P = 0.001), low lumbar BMD (OR, 0.24 [95% CI, 0.07-0.82]; P = 0.023), low total hip BMD (OR, 0.05 [95% CI, 0.00-0.88]; P = 0.041), and lack of antiosteoporosis treatment (OR, 2.71 [95% CI, 2.71-4.08]; P < 0.001) were independent risk factors for second fractures.

CONCLUSIONS

In older women with fractures, BMD was significantly lower in women with second fractures than in those with first fractures. Higher levels of serum CTX and osteocalcin, which indicates increased bone resorption, were negatively correlated with BMD. In women with a first fracture, serum CTX higher than 605 pg/mL was negatively correlated with BMD, whereas no correlation was found between different CTX and BMD in women with second fractures. High BMI and low BMD as well as not receiving antiosteoporosis treatment were independent risk factors for second fractures.

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.

Bavachinin selectively modulates PPAR γ and maintains bone homeostasis in Type 2 Diabetes

Full peroxisome proliferator-activated receptor (PPAR) γ agonists, Thiazolidinediones (TZDs), effectively prevent the process of Type 2 Diabetes Mellitus (T2DM), but their side effects have curtailed use in the clinic, including weight gain and bone loss. Here, we identified that a selective PPAR γ modulator, Bavachinin (BVC), isolated from the seeds of Psoralea Corylifolia L., could potently regulate bone homeostasis. MC3T3-E1 pre-osteoblast cells and C3H10T1/2 mesenchymal stem cells were assessed for osteogenic differentiation activities, and receptor activator of NF-κB ligand (RANKL)-induced RAW 264.7 cells were assessed osteoclasts formation. Leptin receptor-deficient mice and diet-induced obesity mice were applied to evaluate the effect of BVC on bone homeostasis in vivo. Compared to full PPAR γ agonist rosiglitazone, BVC significantly increased the osteogenesis differentiation activities under normal and high glucose conditions in MC3T3-E1 cells. Moreover, BVC could alleviate osteoclast differentiation in RANKL-induced RAW 264.7 cells. In vivo, synthesized BVC prodrug (BN) has been applied to improve water solubility, increase the extent of oral absorption of BVC and prolong its residence time in blood circulation. BN could prevent weight gain, ameliorate lipid metabolism disorders, improve insulin sensitivity, and maintain bone mass and bone biomechanical properties. BVC, a unique PPAR γ selective modulator, could maintain bone homeostasis, and its prodrug (BN) exhibits insulin sensitizer activity while circumventing the side effects of the TZDs, including bone loss and undesirable weight gain.

Diosmin mitigates dexamethasone-induced osteoporosis in vivo: Role of Runx2, RANKL/OPG, and oxidative stress

Secondary osteoporosis is commonly caused by long-term intake of glucocorticoids (GCs), such as dexamethasone (DEX). Diosmin, a natural substance with potent antioxidant and anti-inflammatory properties, is clinically used for treating some vascular disorders. The current work targeted exploring the protective properties of diosmin to counteract DEX-induced osteoporosis in vivo. Rats were administered DEX (7 mg/kg) once weekly for 5 weeks, and in the second week, vehicle or diosmin (50 or 100 mg/kg/day) for the next four weeks. Femur bone tissues were collected and processed for histological and biochemical examinations. The study findings showed that diosmin alleviated the histological bone impairments caused by DEX. In addition, diosmin upregulated the expression of Runt-related transcription factor 2 (Runx2) and phosphorylated protein kinase B (p-AKT) and the mRNA transcripts of Wingless (Wnt) and osteocalcin. Furthermore, diosmin counteracted the rise in the mRNA levels of receptor activator of nuclear factor-kB ligand (RANKL) and the reduction in osteoprotegerin (OPG), both were induced by DEX. Diosmin restored the oxidant/antioxidant equilibrium and exerted significant antiapoptotic activity. The aforementioned effects were more pronounced at the dose level of 100 mg/kg. Collectively, diosmin has proven to protect rats against DEX-induced osteoporosis by augmenting osteoblast and bone development while hindering osteoclast and bone resorption. Our findings could be used as a stand for recommending supplementation of diosmin for patients chronically using GCs.

A narrative review of diabetic bone disease: Characteristics, pathogenesis, and treatment

Recently, the increasing prevalence of diabetes mellitus has made it a major chronic illness which poses a substantial threat to human health. The prevalence of osteoporosis among patients with diabetes mellitus has grown considerably. Diabetic bone disease is a secondary osteoporosis induced by diabetes mellitus. Patients with diabetic bone disease exhibit variable degrees of bone loss, low bone mineral density, bone microarchitecture degradation, and increased bone fragility with continued diabetes mellitus, increasing their risk of fracture and impairing their ability to heal after fractures. At present, there is extensive research interest in diabetic bone disease and many significant outcomes have been reported. However, there are no comprehensive review is reported. This review elaborates on diabetic bone disease in the aspects of characteristics, pathogenesis, and treatment.

Risk factors of primary and recurrent fractures in postmenopausal osteoporotic Chinese patients: A retrospective analysis study

BACKGROUND

As postmenopausal osteoporotic fractures can cause higher rates of disability and mortality in women; it is essential to analyze the factors associated with primary and recurrent fractures in postmenopausal osteoporosis (PMOP) patients.

METHODS

Retrospective analysis of 2478 PMOP patients aged ≥ 50 years who attended the Shanghai General Hospital from January 2007 to December 2016, including 1239 patients with no fractures and 1239 patients with histories of fractures (1008 in the primary fracture group and 231 in the re-fracture group). All patients' basic clinical data, serum biochemical and bone metabolic markers, bone mineral density (BMD), and other indicators were recorded uniformly. Comparing the differences between the clinical characteristics of patients with primary and recurrent fractures, as well as the differences in the clinical characteristics of patients with primary and recurrent fractures in combination with different diseases, further analyses the risk factors for primary and recurrent fractures in PMOP patients. SPSS.26 was used for statistical analysis.

RESULTS

Compared to the unfractured group, the fractured group was older and had lower height and bone mineral density (all P < 0.01), with the re-fractured group having lower BMD at each key site than the primary fracture group (all P < 0.01). Analysis of the combined disease subgroups showed that serum BGP levels were lower in the primary and re-fracture patients with diabetes than in the non-diabetic subgroup (P < 0.05), and serum CTX levels were lower in the re-fracture group with diabetes than in the primary fracture group with diabetes (P < 0.05). Patients with recurrent fractures with cardio-vascular diseases had lower BMD than the subgroup without cardio-vascular diseases (P < 0.05) and also had lower BMD than the group with primary fractures with cardio-vascular diseases (P < 0.05). Multiple logistic regression analysis showed that advanced age, overweight, low lumbar spine and total hip BMD were risk factors for primary and recurrent fractures; and comorbid chronic liver and kidney diseases were risk factors for primary fractures.

CONCLUSION

PMOP patients with advanced age, overweight, low bone mineral density, and comorbid chronic liver and kidney diseases are at greater risk of fractures and require early intervention to reduce fractures occurrence. Moreover, those who are elderly, overweight, and have low bone density should also be aware of the risk of re-fractures.

Crossing Phylums: Butterfly Wing as a Natural Perfusable Three-Dimensional (3D) Bioconstruct for Bone Tissue Engineering

Despite the advent of promising technologies in tissue engineering, finding a biomimetic 3D bio-construct capable of enhancing cell attachment, maintenance, and function is still a challenge in producing tailorable scaffolds for bone regeneration. Here, osteostimulatory effects of the butterfly wings as a naturally porous and non-toxic chitinous scaffold on mesenchymal stromal cells are assessed. The topographical characterization of the butterfly wings implied their ability to mimic bone tissue microenvironment, whereas their regenerative potential was validated after a 14-day cell culture. In vivo analysis showed that the scaffold induced no major inflammatory response in Wistar rats. Topographical features of the bioconstruct upregulated the osteogenic genes, including COL1A1, ALP, BGLAP, SPP1, SP7, and AML3 in differentiated cells compared to the cells cultured in the culture plate. However, butterfly wings were shown to provide a biomimetic microstructure and proper bone regenerative capacity through a unique combination of various structural and material properties. Therefore, this novel platform can be confidently recommended for bone tissue engineering applications.