Gut microbiota and microbial metabolites for osteoporosis

Osteoporosis is an age-related bone metabolic disease. As an essential endocrine organ, the skeletal system is intricately connected with extraosseous organs. The crosstalk between bones and other organs supports this view. In recent years, the link between the gut microecology and bone metabolism has become an important research topic, both in preclinical studies and in clinical trials. Many studies have shown that skeletal changes are accompanied by changes in the composition and structure of the gut microbiota (GM). At the same time, natural or artificial interventions targeting the GM can subsequently affect bone metabolism. Moreover, microbiome-related metabolites may have important effects on bone metabolism. We aim to review the relationships among the GM, microbial metabolites, and bone metabolism and to summarize the potential mechanisms involved and the theory of the gut‒bone axis. We also describe existing bottlenecks in laboratory studies, as well as existing challenges in clinical settings, and propose possible future research directions.

Causal associations of metabolic dysfunction-associated steatotic liver disease with gestational hypertension and preeclampsia: a two-sample Mendelian randomization study

BACKGROUND

Hypertensive disorders of pregnancy (HDPs), which include gestational hypertension (GH) and preeclampsia (PE), are the primary causes of maternal morbidity and mortality worldwide. Recent studies have found a correlation between metabolic dysfunction-associated steatotic liver disease (MASLD) and HDPs, but the causality of this association remains to be identified. Therefore, this study aims to evaluate the causal relationship between MASLD and HDPs through Mendelian randomization (MR) analysis.

METHODS

The summary statistics from genome-wide association studies were employed to conduct a two-sample MR analysis. Five complementary MR methods, including inverse variance weighting (IVW), MR-Egger, weighted median, simple mode and weighted mode were performed to assess the causality of MASLD on GH and PE. Furthermore, we conducted various sensitivity analyses to ensure the stability and reliability of the results.

RESULTS

Genetically predicted MASLD significantly increased the risk of GH (IVW: OR = 1.138, 95% CI: 1.062-1.220, p < 0.001), while there was little evidence of a causal relationship between MASLD and PE (IVW: OR = 0.980, 95% CI: 0.910-1.056, p = 0.594). The sensitivity analyses indicated no presence of heterogeneity and horizontal pleiotropy.

CONCLUSION

This MR study provided evidence supporting the causal effect of MASLD on GH. Our findings underscore the significance of providing more intensive prenatal care and early intervention for pregnant women with MASLD to prevent potential adverse obstetric outcomes.

Urinary pentosidine as a potential biomarker of impaired bone health: a systematic review and meta-analysis

Background

Urinary pentosidine, an advanced glycation end product (AGE), has been proposed as a potential biomarker for impaired bone health, especially in older adults and those with diabetes. This study aimed to systematically review and meta-analyze the association of urinary pentosidine with bone mineral density (BMD) and fracture risk.

Methods

A comprehensive search of Embase, PubMed, Scopus, and Web of Science databases was conducted and records were gathered from 1960 to February 2024. Relevant papers were screened and data were extracted by two independent reviewers. Hedges' g standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated to compare urinary pentosidine levels between patients with and without fractures.

Results

A total of 12 studies comprising 5,878 participants were included in the systematic review. The meta-analysis revealed that patients with fractures had significantly higher urinary pentosidine levels compared to those without fractures (SMD [95% CI] = 0.53 [0.39-0.68]; I² = 54%; P < 0.01). In patients with vertebral fractures, pentosidine levels were also elevated (SMD [95% CI] = 0.51 [0.32-0.70]; I² = 64%; P < 0.01). Additionally, some studies demonstrated that an increase in urinary pentosidine was significantly associated with fracture risk (aHR = 1.20 [95% CI = 1.07-1.33]; P = 0.001) and BMD reduction (β = -0.125 [95% CI = -0.248, -0.002]; P = 0.047). However, other studies showed inconsistent results, particularly regarding the association between pentosidine and BMD or fracture risk in non-diabetic populations (aRR [95%CI] = 1.08 [0.79-1.49]; P = 0.6). Diagnostic accuracy analyses revealed a sensitivity of 71.9% and specificity of 61.2% for urinary pentosidine in predicting vertebral fracture in patients with type 2 diabetes mellitus.

Conclusion

This systematic review and meta-analysis demonstrate that elevated urinary pentosidine levels are associated with an increased risk of fractures and, to a lesser extent, reduced bone mineral density. Its diagnostic accuracy improves when integrated with other clinical markers, such as BMD and bone turnover indices. However, due to the variability in results, further research is needed to standardize pentosidine's use as a reliable biomarker for impaired bone health in clinical practice.

Zebrafish navigating the metabolic maze: insights into human disease - assets, challenges and future implications

Zebrafish (Danio rerio) have become indispensable models for advancing our understanding of multiple metabolic disorders such as obesity, diabetes mellitus, dyslipidemia, and metabolic syndrome. This review provides a comprehensive analysis of zebrafish as a powerful tool for dissecting the genetic and molecular mechanisms of these diseases, focusing on key genes, like pparγ, lepr, ins, and srebp. Zebrafish offer distinct advantages, including genetic tractability, optical transparency in early development, and the conservation of key metabolic pathways with humans. Studies have successfully used zebrafish to uncover conserved metabolic mechanisms, identify novel disease pathways, and facilitate high-throughput screening of potential therapeutic compounds. The review also highlights the novelty of using zebrafish to model multifactorial metabolic disorders, addressing challenges such as interspecies differences in metabolism and the complexity of human metabolic disease etiology. Moving forward, future research will benefit from integrating advanced omics technologies to map disease-specific molecular signatures, applying personalized medicine approaches to optimize treatments, and utilizing computational models to predict therapeutic outcomes. By embracing these innovative strategies, zebrafish research has the potential to revolutionize the diagnosis, treatment, and prevention of metabolic disorders, offering new avenues for translational applications. Continued interdisciplinary collaboration and investment in zebrafish-based studies will be crucial to fully harnessing their potential for advancing therapeutic development.

Could point-of-care bioimpedance analysis be another tool in the prevention of osteoporotic fractures?

A treatment gap exists in osteoporosis, with people at risk of fracture often not identified. Dual X-Ray Absorptiometry is the gold standard technique for the identification of low bone mass, but it is not always easily accessible. Bioimpedance analysis (BIA) is a non-invasive, safe and portable technology, which can provide a calculated estimate of bone mass. However, the validity of using BIA in the assessment of bone health is largely unknown. The objective of this study was to examine BIA-derived bone mass (BBM) data from a local population, with the aim of exploring its potential for use as a preliminary osteoporosis screening tool. A convenience sample of 124 participants (40 males, 84 females) was recruited from the local population. BIA was performed on participants according to standard procedures. BBM data was analysed in relation to weight, height, sex, age and BMI. Data was analysed using ANOVA, hierarchial regression, and bivariate correlation as appropriate. Weight was strongly associated with BBM (R2 = 0.637, p < 0.001), providing the greatest contribution to variance, of the factors examined. BBM was also positively associated with height, in a model that included weight (ΔR2 = 0.218, p < 0.001). Females had a significantly lower bone mass than males, independent of weight and height (ΔR2 = 0.055, p < 0.001). There was a small negative association of BBM with age, in a model that included weight and sex (ΔR2 = 0.011; p = 0.002). A positive correlation between BMI and BBM was found in both males (r s (38) = 0.482, p = 0.002), and females (r s (82) = 0.565, p < 0.001). The finding that BBM values are associated with factors known to be relevant to fracture risk, provides a rationale to perform further studies to investigate if BBM values could have validity for point-of-care assessment of bone health.

Uncemented versus cemented humeral fixation during reverse total shoulder arthroplasty for proximal humerus fracture

Introduction

Over time, the use of reverse total shoulder arthroplasty (RTSA) treating proximal humerus fractures (PHFs) and fracture sequelae has grown significantly due to its demonstrated effectiveness over open reduction internal fixation (ORIF) and hemiarthroplasty (HA). Cemented humeral stems have been widely utilized in RTSA for PHF, however cementless alternatives have become increasingly popular. This study seeks to analyze outcomes and complications in patients undergoing RTSA for fracture with uncemented and cemented stems at mid-term follow-up.

Methods

Patient records were queried for all patients who underwent reverse total shoulder arthroplasty for fracture with between January 7, 2009 and January 10, 2019 and completed a minimum follow-up of 2 years. Demographics characteristics, post-operative functional measurements, complications, and radiographs were assessed. A 5-year Kaplan-Meier survival analysis was performed.

Results

A total of 23 patients encompassing 11 cemented and 12 uncemented stems met the inclusion criteria. The mean age of the uncemented cohort was 70.0 ± 9.8 years with a mean follow-up of 2.6 ± 1.3 years while the mean age of the cemented cohort was 68.9 ± 9.2 years with a mean follow-up of 2.9 ± 1.1 years. No differences in strength, range of motion, or survival between groups were observed. Two patients in the cemented cohort demonstrated humeral component loosening on follow-up radiographs.

Discussion

Uncemented and cemented humeral fixation during RTSA for proximal humerus fracture leads to similar outcomes, and thus both are safe and effective methods of achieving humeral fixation in fracture patients.

Visible light-induced simultaneous bioactive amorphous calcium phosphate mineralization and in situ crosslinking of coacervate-based injectable underwater adhesive hydrogels for enhanced bone regeneration

The field of bone tissue engineering is vital due to increasing bone disorders and limitations of traditional grafts. Injectable hydrogels offer minimally invasive solutions but often lack mechanical integrity and biological functionality, including osteoinductive capacity and structural stability under physiological conditions. To address these issues, we propose a coacervate-based injectable adhesive hydrogel that utilizes the dual functionality of in situ photocrosslinking and osteoinductive amorphous calcium phosphate formation, both of which are activated simultaneously by visible light irradiation. The developed hydrogel formulation integrated a photoreactive agent with calcium ions and phosphonodiol in a matrix of tyramine-conjugated alginate and RGD peptide-fused bioengineered mussel adhesive protein, promoting rapid setting, robust underwater adhesion, and bioactive mineral deposition. The hydrogel also exhibited superior mechanical properties, including enhanced underwater tissue adhesive strength and compressive resistance. In vivo evaluation using a rat femoral tunnel defect model confirmed the efficacy of the developed adhesive hydrogel in facilitating easy application to irregularly shaped defects through injection, rapid bone regeneration without the addition of bone grafts, and integration within the defect sites. This injectable adhesive hydrogel system holds significant potential for advancing bone tissue engineering, providing a versatile, efficient, and biologically favorable alternative to conventional bone repair methodologies.

Calcium phosphate nanoclusters modify periodontium remodeling and minimize orthodontic relapse

Orthodontic relapse is one of the most prevalent concerns of orthodontic therapy. Relapse results in patients' teeth reverting towards their pretreatment positions, which increases the susceptibility to functional problems, dental disease, and substantially increases the financial burden for retreatment. This phenomenon is thought to be induced by rapid remodeling of the periodontal ligament (PDL) in the early stages and poor bone quality in the later stages. Current therapies including fixed or removable retainers and fiberotomies have limitations with patient compliance and invasiveness. Approaches using biocompatible biomaterials, such as calcium phosphate polymer-induced liquid precursors (PILP), are an ideal translational approach for minimizing orthodontic relapse. Here, post-orthodontic relapse is reduced after a single injection of high concentration PILP (HC-PILP) nanoclusters by altering PDL remodeling in the early stage of relapse and improving trabecular bone quality in the later stage. HC-PILP nanoclusters are achieved by using high molecular weight poly aspartic acid (PASP, 14 kDa) and poly acrylic acid (PAA, 450 kDa), which resulted in a stable solution of high calcium and phosphate concentrations without premature precipitation. In vitro results show that HC-PILP nanoclusters prevented collagen type-I mineralization, which is essential for the tooth-PDL-bone interphase. In vivo experiments show that the HC-PILP nanoclusters minimize relapse and improve the trabecular bone quality in the late stages of relapse. Interestingly, HC-PILP nanoclusters also altered the remodeling of the PDL collagen during the early stages of relapse. Further in vitro experiments showed that HC-PILP nanoclusters alter the fibrillogenesis of collagen type-I by impacting the protein secondary structure and forming aggregates. These findings propose a new approach for treating orthodontic relapse and provide additional insight into the PILP nanocluster's structure and properties on collagenous structure repair.

Bone mineral density affects tumor growth by shaping microenvironmental heterogeneity

Breast cancer bone metastasis is a major cause of mortality in patients with advanced breast cancer. Although decreased mineral density is a known risk factor for bone metastasis, the underlying mechanisms remain poorly understood because studying the isolated effect of bone mineral density on tumor heterogeneity is challenging with conventional approaches. Moreover, mineralized biomaterials are commonly utilized for clinical bone defect repair, but how mineralized biomaterials affect the foreign body response and wound healing is unclear. Here, we investigate how bone mineral affects tumor growth and microenvironmental complexity in vivo by combining single-cell RNA-sequencing with mineral-containing or mineral-free decellularized bone matrices. We discover that the absence of bone mineral significantly influences fibroblast and immune cell heterogeneity, promoting phenotypes that increase tumor growth and alter the response to injury or disease. Importantly, we observe that the stromal response to bone mineral content depends on the murine tumor model used. While lack of bone mineral induces tumor-promoting microenvironments in both immunocompromised and immunocompetent animals, these changes are mediated by altered fibroblast phenotype in immunocompromised mice and macrophage polarization in immunocompetent mice. Collectively, our findings suggest that bone mineral density affects tumor growth by impacting microenvironmental complexity in an organism-dependent manner.

Regulatory T cells engineered with polyphenol-functionalized immunosuppressant nanocomplexes for rebuilding periodontal hard tissue under inflammation-challenged microenvironment

Global aging heightens the risk of oral disorders, among which periodontitis is the major cause of tooth loss in the aging population. The regeneration of damaged periodontal hard tissue is highly challenging due to the existence of the refractory local inflammation. Owing to the potent anti-inflammatory capabilities, regulatory T cells hold great promise in immunotherapies for tissue regeneration. However, the transferred regulatory T cells can alter their phenotypes and functions in local inflammatory milieu, significantly impairing their therapeutic efficacy. Herein, we introduce a novel regulatory T cell-based nanobiohybrid system bearing polyphenol-functionalized rapamycin nanocomplexes. The sustained in situ release of immunosuppressant rapamycin from the cell-attached nanocomplexes maintains the anti-inflammatory phenotype of regulatory T cells in the inflammatory milieu. The synergistic actions of the anti-inflammatory cytokines secreted and the immunosuppressant released guide a pro-resolving polarization of macrophages and enhance osteogenic differentiation of bone marrow-derived stromal cells. The stabilized phenotype of the regulatory T cells dramatically promoted the resolution of periodontal inflammation and the repair of the hard tissue (alveolar bone) in vivo. Overall, these studies highlight a potent regulatory T cell-based nanobiohybrid therapy to treat periodontitis by modulating periodontal immune microenvironment.

Who breaks their hip? A decade of traumatic hip fracture data

Aims & objectives

Hip fractures lead to significant morbidity, mortality, and healthcare costs, particularly in elderly populations. Understanding the mechanisms underlying these fractures is crucial for developing targeted prevention strategies and counseling patients.

Methods

The National Electronic Injury Surveillance System (NEISS) was utilized to identify a cohort of 25,068 hip fractures from 2013 to 2022. The inclusion criteria mandated classification as a lower trunk fracture and explicit mention of hip fracture in the narrative. Patient age, race, sex, incident location, the time of year, and associated consumer products were compared using 95% confidence intervals and Chi-Squared tests of independence.

Results

A total of 25,068 hip fracture patients were included in this study. Females were more likely to fracture their hip (P < .001) representing 68.4% (95% CI 67.8%-69.0%) of all fractures. Patients were most likely to injure themselves at home (P < .001), accounting for 62.0 % (95% CI 61.4%-62.6%) of fractures. Falls to the floor represented 36.0 % (95% CI 35.4%-36.6%) of fractures, while fractures related to beds, stairs, and chairs emerged as other prevalent mechanisms at 11.2% (95% CI 10.8%-11.6%), 7.9% (95% CI 7.5%-8.2%), and 5.4% (95% CI 5.1%-5.7%), respectively. In the 50-60 age group, stairs present a prominent risk, representing 12.4% (95% CI 10.6%-14.5%) of fractures. Younger individuals suffered fractures most commonly due to high energy activities, such as falls from ladders, bicycles, and stairs (P < .001).

Conclusion

While falls remain the chief cause of hip fractures, many of these injuries stem from overlooked mechanisms. The heightened risk associated with falls from beds and chairs in the elderly, stair-related injuries in middle-aged individuals, and high-force modalities in younger people, highlights the necessity for tailored preventive measures. Providers should counsel their patients on risk reduction measures within the home, while Medicare and other insurers must work to expand coverage for these same measures.

Multivariate analysis of Raman spectra for discriminating human collagens: In vitro identification of extracellular matrix collagens produced by an osteosarcoma cell line

BACKGROUND

The NHS spends £4.3 billion annually to address musculoskeletal conditions, encompassing age-related bone disorders like osteoarthritis and osteoporosis. Traditional X-ray diagnostic methods are commonly employed for bone disorder diagnosis, primarily assessing gross anatomical bone structure changes. However, these methods are unable to identify subtle biochemical alterations within the bone. More detailed information, particularly about protein changes, may lead to enhanced diagnostics and treatment. Raman spectroscopy is a non-invasive, laser-based technique capable of detecting changes in the collagen component of bone. Despite its long-standing application in discerning mineral and protein changes within bone, there is limited evidence on Raman spectral signatures of purified human collagens and their differentiation. This study aimed to test the hypothesis that Raman spectroscopy could detect different types of collagen in the human body.

RESULTS

A Raman microspectrometer with a 785 nm laser was used to measure unmineralized human collagens types I - VI and collagenous extracellular matrix (ECM) secreted by MG63 osteoblast-like cells. The results demonstrated the efficacy of Raman spectroscopy and subsequent multivariate analysis in distinguishing human collagen types I - VI. This implies that Raman spectroscopy, coupled with multivariate analysis, can identify pure human collagens and offers reference spectra similar to natural human collagen in the bone extracellular matrix.

SIGNIFICANCE

This study establishes Raman spectroscopy as a tool for identifying and characterizing human collagens, aiding in the diagnosis of connective tissue disorders. The creation of a spectral reference library for pure human collagen types I - VI holds potential for medical diagnostics, analytical chemistry, and materials science applications.

CCDC134 controls TLR biogenesis through the ER chaperone Gp96

Toll-like receptors (TLRs) are central to initiate immune responses against invading pathogens. To ensure host defense while avoiding aberrant activation leading to pathogenic inflammation and autoimmune diseases, TLRs are tightly controlled by multilevel regulatory mechanisms. Through a loss-of-function genetic screen in a reporter cell line engineered to undergo cell death upon TLR7-induced IRF5 activation, we identified here CCDC134 as an essential factor for TLR responses. CCDC134 deficiency impaired endolysosomal TLR-induced NF-κB, MAPK, and IRF5 activation, as well as downstream production of proinflammatory cytokines and type I interferons. We further demonstrated that CCDC134 is an endoplasmic reticulum (ER)-resident interactor of Gp96 (HSP90B1/Grp94), an ER chaperone essential for folding and trafficking of plasma membrane and endolysosomal TLRs. CCDC134 controlled Gp96 stability as its loss led to Gp96 hyperglycosylation and ER-associated protein degradation (ERAD)-mediated clearance. Accordingly, CCDC134 deficiency impaired the folding, maturation, and trafficking of TLRs, resulting in blunted inflammatory responses upon stimulation. Altogether, this study reveals CCDC134 as a central regulator of the chaperone Gp96, thereby controlling TLR biogenesis and responses.

Impact of stopping burosumab treatment at the end of skeletal growth in adolescents with X-linked hypophosphatemia (XLH)

Many adolescents with X-linked hypophosphatemia (XLH) currently have to stop treatment with burosumab at the end of skeletal growth. We describe the experience of a cohort of adolescents with XLH before, during, and after stopping burosumab (median treatment duration 37.5 months). Improvements in serum phosphate, pain, mobility, function, and quality of life noted during burosumab treatment were reversed after treatment cessation. Further real-world data are needed to explore the value of uninterrupted burosumab treatment in adolescents.

Reduction reactions dominate the interactions between Mg alloys and cells: Understanding the mechanisms

Magnesium (Mg) alloys are popular biodegradable metals studied for orthopedic and cardiovascular applications, mainly because Mg ions are essential trace elements known to promote angiogenesis and osteogenesis. However, Mg corrosion consists of oxidation and reduction reactions that produce by-products, such as hydrogen gas, reactive oxygen species, and hydroxides. It is still unclear how all these by-products and Mg ions concomitantly alter the microenvironment and cell behaviors spatially and temporally. This study shows that Mg corrosion can enhance cell proliferation by reducing intracellular ROS. However, Mg cannot decrease ROS and promote cell proliferation in simulated inflammatory conditions, meaning the microenvironment is critical. Furthermore, cells may respond to Mg ions differently in chronic or acute alkaline pH or oxidative stress. Depending on the corrosion rate, Mg modulates HIF1α and many signaling pathways like PI3K/AKT/mTOR, mitophagy, cell cycle, and oxidative phosphorylation. Therefore, this study provides a fundamental insight into the importance of reduction reactions in Mg alloys.

Multifaceted bone response to immunomodulatory magnesium implants: Osteopromotion at the interface and adipogenesis in the bone marrow

Orthopedic implants made of biodegradable magnesium (Mg) provide an alternative to nondegradable implants for fracture repair. Widely reported to be pro-osteogenic, Mg implants are also believed to be anti-inflammatory and anti-osteoclastic, but this is difficult to reconcile with the early clinical inflammation observed around these implants. Here, by surveying implant healing in a rat bone model, we determined the cellular responses and structural assembly of bone correlated with the surface changes of Mg implants inherent in degradation. We show that, compared to titanium, both high-purity (99.998 %) and clinical-grade, rare earth-alloyed (MgYREZr) Mg implants create an initial, transient proinflammatory environment that facilitates inducible nitric oxide synthase-mediated macrophage polarization, osteoclastogenesis, and neoangiogenesis programs. While this immunomodulation subsequently reinforces reparative osteogenesis at the surface of both Mg implants, the faster degradation of high-purity Mg implants, but not MgYREZr implants, elicits a compositional alteration in the interfacial bone and a previously unknown proadipogenic response with persistent low-grade inflammation in the surrounding bone marrow. Beyond the need for rigorous tailoring of Mg implants, these data highlight the need to closely monitor osseointegration not only at the immediate implant surface but also in the peri-implant bone and adjacent bone marrow.

Rapid assessment of the osteogenic capacity of hydroxyapatite/aragonite using a murine tibial periosteal ossification model

Biomaterials are widely used as orthopaedic implants and bone graft substitutes. We aimed to develop a rapid osteogenic assessment method using a murine tibial periosteal ossification model to evaluate the bone formation/remodelling potential of a biomaterial within 2-4 weeks. A novel hydroxyapatite/aragonite (HAA) biomaterial was implanted into C57BL/6 mice juxtaskeletally between the tibia and tibialis anterior muscle. Rapid intramembranous bone formation was observed at 14 days, with 4- to 8-fold increases in bone thickness and callus volume in comparison with sham-operated animals (p < 0.0001), followed by bone remodelling and a new layer of cortical bone formation by 28 days after implantation. The addition of zoledronate, a clinically-utilised bisphosphonate, to HAA, promoted significantly more new bone formation than HAA alone over 28 days (p < 0.01). The osteogenic potential of HAA was further confirmed by implanting into a 3.5 mm diameter femoral cancellous bone defect in rats and a 5 mm diameter femoral cortical bone defect in minipigs. To understand the biodegradation and the cellular activity at the cell/biomaterial interfaces, non-decalcified specimens were resin embedded and sections subjected to combined scanning electron microscopy (SEM)/electron backscatter diffraction (EBSD)/energy dispersive X-ray spectrometry (EDS) analysis. We conclude that murine tibial periosteal ossification is a novel method for rapid assessment of the interaction of bioactive materials with osteogenic tissues. This study also highlights that combining calcium carbonate with hydroxyapatite enhances biodegradation and osteogenesis.

Engineering soft-hard tissue interfaces in dental and craniofacial system by spatially controlled bioactivities

The interface between soft and hard tissues is constituted by a gradient change of cell types and matrix compositions that are optimally designed for proper load transmission and injury protection. In the musculoskeletal system, the soft-hard tissue interfaces at tendon-bone, ligament-bone, and meniscus-bone have been extensively researched as regenerative targets. Similarly, extensive research efforts have been made to guide the regeneration of multi-tissue complexes in periodontium. However, the other soft-hard tissue interfaces in the dental and craniofacial system have been somewhat neglected. This review discusses the clinical significance of developing regenerative strategies for soft-hard tissue interfaces in the dental and craniofacial system. It also discusses the research progress in the field focused on bioengineering approaches using 3D scaffolds equipped with spatially controlled bioactivities. The remaining challenges, future perspectives, and considerations for the clinical translation of bioactive scaffolds are also discussed.

MicroRNA-181a/b-1 enhances chondroprogenitor anabolism and downregulates aquaporin-9

Objective

Effective osteoarthritis treatments that enhance the anabolic/regenerative capacity of chondrocytes are needed. Studying cartilage development processes may inform us of approaches to control chondrocyte differentiation and anabolism and, ultimately, how to effectively treat OA. MicroRNAs are broad-acting epigenetic regulators known to affect many skeletal processes. Previous reports from our group indicated that miR-181a-1 is upregulated during chondrocyte differentiation. The goal of this study was to determine how the entire miR-181a/b-1 cluster regulates in vitro chondrogenesis.

Design

Precursor miR-181a/b-1 was over-expressed in cartilage progenitor cells using lentiviral technology Transduced cartilage progenitor cells were cultured as micromass pellets in hypoxic conditions and stimulated to undergo chondrogenic differentiation for five weeks. Bulk RNA-sequencing and immunostaining was applied to evaluate chondrogenic differentiation and matrix production.

Results

Immunostaining of cartilage pellet sections showed that miR-181a/b-1 increased mature type II collagen and decreased expression of the chondroprogenitor type IIA collagen isoform. Bulk RNA-Seq at day 7 of chondrogenesis revealed upregulation of pro-anabolic genes such as COL2A1, COL9A2/3, COL11A2 and SNORC. Of the genes significantly downregulated by miR-181a/b-1, aquaporin 9 (AQP9) was the top hit which decreased in expression by over 14-fold. While a predicted target of miR-181a/b, our data showed that this miRNA cluster likely suppresses AQP9 via an indirect targeting mechanism.

Conclusions

Our findings demonstrate a pro-differentiation/anabolic function for miR-181a/b-1 during in vitro chondrogenesis that may be due, in part, to suppression of AQP9. Future studies are needed to elucidate the role of this membrane channel protein in regulating chondrocyte differentiation and homeostasis.

Controlled lipid digestion in the development of functional and personalized foods for a tailored delivery of dietary fats

In recent decades, obesity and its associated health issues have risen dramatically. The COVID-19 pandemic has further exacerbated this trend, underscoring the pressing need for new strategies to manage weight. Functional foods designed to modulate lipid digestion and absorption rates and thereby reduce the assimilation of dietary fats have gained increasing attention in food science as a potentially safer alternative to weight-loss medications. This review provides insights into controlled lipid digestion and customized delivery of fats. The first section introduces basic concepts of lipid digestion and absorption in the human gastrointestinal tract. The second section discusses factors regulating lipid digestion and absorption rates, as well as strategies for modulating lipid assimilation from food. The third section focuses on applications of controlled lipid digestion in developing personalized foods designed for specific consumer groups, with particular emphasis on two target populations: overweight individuals and infants.

Association between body mass index and lumbar spine volumetric bone mineral density in diabetic and non-diabetic patients

BACKGROUND

The association between body mass index (BMI) and bone mineral density (BMD) has shown inconsistent results, varying by sex and skeletal site. Despite normal or elevated bone mass, individuals with type 2 diabetes have an increased risk of hip and vertebral fractures.

AIM

To assess lumbar spine trabecular volumetric BMD (vBMD) across different BMI categories in individuals with and without diabetes.

METHODS

This cross-sectional study included 966 men over 50 years old and 1001 postmenopausal women from the Pinggu Metabolic Disease Study. The vBMD of lumbar vertebrae 2 through 4 was measured using quantitative computed tomography. Total adipose tissue, subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and lumbar skeletal muscle area were also quantified.

RESULTS

In men with obesity (P = 0.038) and overweight (P = 0.032), vBMD was significantly higher in the diabetes group compared to non-diabetic men. After adjusting for age and sex, no significant saturation effect between BMI and BMD was found in participants with diabetes or in women without diabetes. However, a BMI threshold of 22.33 kg/m² indicated a saturation point for vBMD in non-diabetic men. Independent predictors of vBMD in men included age (r = -0.387, P < 0.001), BMI (r = 0.130, P = 0.004), and VAT (r = -0.145, P = 0.001). For women, significant predictors were age (r = -0.594, P < 0.001), BMI (r = 0.157, P = 0.004), VAT (r = -0.112, P = 0.001), and SAT (r = -0.068, P = 0.035).

CONCLUSION

The relationship between BMI and trabecular vBMD differs in individuals with and without diabetes. Overweight and obese men with diabetes exhibit higher vBMD.

Role of glutaminyl-peptide cyclo-transferase-like protein (QPCTL) in cancer: From molecular mechanisms to immunotherapy

Glutaminyl-peptide cyclotransferase-like protein (QPCTL) is a newly discovered enzyme that has sparked interest owing to its possible role in cancer genesis and progression. Initially discovered as a post-translational modification regulator of protein maturation, QPCTL has emerged as a key participant in cancer biology. Recent research has linked QPCTL to numerous essential cancer-related processes, including cell proliferation, migration, invasion, and apoptosis. Furthermore, QPCTL expression changes have been seen in a variety of cancer types, underlining its potential as a diagnostic and prognostic marker. The molecular mechanisms behind QPCTL's participation in cancer will be examined in this review. We investigate its involvement in the control of signaling pathways and the modification of cellular activities that are important in cancer. We also examine the clinical importance of QPCTL, including as its relationship with tumor development, metastasis, and response to treatment. We also discuss the possible therapeutic implications of targeting QPCTL in cancer therapy. QPCTL is a prospective target for the development of innovative anticancer treatments due to its participation in several cancer-associated pathways.

C2C12 myoblasts differentiate into myofibroblasts via the TGF-β1 signaling pathway mediated by Fibulin2

Myoblasts play a critical role in the regeneration of skeletal muscle following injury. It has been reported that local elevation of transforming growth factor-β1 (TGF-β1) after skeletal muscle injury induces differentiation of myoblasts into myofibroblasts. However, the mechanisms underlying this differentiation process remain incompletely understood. In this study, we found that Fibulin2 expression significantly increases in myoblasts in response to TGF-β1 stimulation. Elevated Fibulin2 levels enhance the expression of fibrotic markers. Conversely, downregulation of Fibulin2 in myoblasts inhibits the upregulation of fibrotic markers induced by TGF-β1 stimulation. Extracellular secretion of Fibulin2 activates the TGF-β1-Smad2 pathway, thereby promoting the upregulation of fibrotic markers. Hence, Fibulin2 and TGF-β1 form a positive feedback loop that facilitates differentiation of myoblasts into myofibroblasts.

3D-printed manganese dioxide incorporated scaffold promotes osteogenic-angiogenic coupling for refractory bone defect by remodeling osteo-regenerative microenvironment

The treatment of refractory bone defects is a major clinical challenge, especially in steroid-associated osteonecrosis (SAON), which is characterized by insufficient osteogenesis and angiogenesis. Herin, a microenvironment responsiveness scaffold composed of poly-L-lactide (PLLA), and manganese dioxide (MnO2) nanoparticles is designed to enhance bone regeneration by scavenging endogenous reactive oxygen species (ROS) and modulating immune microenvironment in situ. A catalase-like catalytic reaction between MnO2 and endogenous hydrogen peroxide (H2O2) generated at the bone defect area, which typically becomes acidic and ROS-rich, triggers on-demand release of oxygen and Mn2+, significantly ameliorating inflammatory response by promoting M2-type polarization of macrophages, reprograming osteoimmune microenvironment conducive to angiogenesis and osteogenesis. Furthermore, the fundamental mechanisms were explored through transcriptome sequencing analysis, revealing that PLLA/MnO2 scaffolds (PMns) promote osteogenic differentiation by upregulating the TGF-β/Smad signaling pathway in human bone marrow mesenchymal stem cells (hBMSCs). Overall, the PMns exhibit superior immunomodulatory, excellent osteogenic-angiogenic properties and promising candidates as bone graft substitutes for therapy clinical refractory bone defects.

Precision pore structure optimization of additive manufacturing porous tantalum scaffolds for bone regeneration: A proof-of-concept study

Currently, the treatment of bone defects in arthroplasty is a challenge in clinical practice. Nonetheless, commercially available orthopaedic scaffolds have shown limited therapeutic effects for large bone defects, especially for massiveand irregular defects. Additively manufactured porous tantalum, in particular, has emerged as a promising material for such scaffolds and is widely used in orthopaedics for its exceptional biocompatibility, osteoinduction, and mechanical properties. Porous tantalum has also exhibited unique advantages in personalised rapid manufacturing, which allows for the creation of customised scaffolds with complex geometric shapes for clinical applications at a low cost and high efficiency. However, studies on the effect of the pore structure of additively manufactured porous tantalum on bone regeneration have been rare. In this study, our group designed and fabricated a batch of precision porous tantalum scaffolds via laser powder bed fusion (LPBF) with pore sizes of 250 μm (Ta 250), 450 μm (Ta 450), 650 μm (Ta 650), and 850 μm (Ta 850). We then performed a series of in vitro experiments and observed that all four groups showed good biocompatibility. In particular, Ta 450 demonstrated the best osteogenic performance. Afterwards, our team used a rat bone defect model to determine the in vivo osteogenic effects. Based on micro-computed tomography and histology, we identified that Ta 450 exhibited the best bone ingrowth performance. Subsequently, sheep femur and hip defect models were used to further confirm the osteogenic effects of Ta 450 scaffolds. Finally, we verified the aforementioned in vitro and in vivo results via clinical application (seven patients waiting for revision total hip arthroplasty) of the Ta 450 scaffold. The clinical results confirmed that Ta 450 had satisfactory clinical outcomes up to the 12-month follow-up. In summary, our findings indicate that 450 μm is the suitable pore size for porous tantalum scaffolds. This study may provide a new therapeutic strategy for the treatment of massive, irreparable, and protracted bone defects in arthroplasty.

Periosteum-bone inspired hierarchical scaffold with endogenous piezoelectricity for neuro-vascularized bone regeneration

The development of scaffolds for repairing critical-sized bone defects heavily relies on establishing a neuro-vascularized network for proper penetration of nerves and blood vessels. Despite significant advancements in using artificial bone-like scaffolds infused with various agents, challenges remain. Natural bone tissue consists of a porous bone matrix surrounded by a neuro-vascularized periosteum, with unique piezoelectric properties essential for bone growth. Drawing inspiration from this assembly, we developed a periosteum-bone-mimicking bilayer scaffold with piezoelectric properties for regeneration of critical-sized bone defects. The periosteum-like layer of this scaffold features a double network hydrogel composed of chelated alginate, gelatin methacrylate, and sintered whitlockite nanoparticles, emulating the viscoelastic and piezoelectric properties of the natural periosteum. The bone-like layer is composed of a porous structure of chitosan and bioactive hydroxyapatite created through a biomineralization process. Unlike conventional bone-like scaffolds, this bioinspired bilayer scaffold significantly enhances osteogenesis, angiogenesis, and neurogenesis combined with low-intensity pulsed ultrasound-assisted piezoelectric stimulation. Such a scheme enhances neuro-vascularized bone regeneration in vivo. The results suggest that the bilayer scaffold could serve as an effective self-powered electrical stimulator to expedite bone regeneration under dynamic physical stimulation.

Bone Health following Spinal Cord Injury: A Clinical Guide to Assessment and Management

A marked decrease in bone mineral density is a well recognized, if not always fully addressed, spinal cord injury-related comorbidity. The bone loss starts shortly after paralysis onset, and the loss rate is steep. The diverse etiology includes mechanical, neurologic, endocrine, vascular, and pharmacologic factors. Dual x-ray absorptiometry is available and affordable to quantify the degree of bone loss and follow changes related to treatment. Fragility/low impact fractures occur frequently and can induce significant morbidity. Physical modalities and pharmacologic interventions can be employed to stave off and/or reverse bone loss with variable success rates.

Extracellular acidification stimulates OGR1 to modify osteoclast differentiation and activity through the Ca2+‑calcineurin‑NFATc1 pathway

The aim of the present study was to explore the role of ovarian cancer G protein-coupled receptor 1 (OGR1) in osteoclast differentiation and activity induced by extracellular acid. The impact of extracellular acidification on osteoclasts was investigated. Briefly, osteoclasts were generated from RAW 264.7 cells using 100 ng/ml receptor activator of nuclear factor-κB ligand in cell culture media at pH 6.8 or 7.4. Tartrate-resistant acid phosphatase (TRAP) staining and the bone resorption pit assay were used to detect the effects of extracellular acid on the number and absorptive capacity of osteoclasts. Intracellular Ca2+ levels were analyzed using laser scanning confocal microscopy. Reverse transcription-quantitative PCR was used to detect the expression levels of genes associated with osteoclast formation and bone erosion. The role of OGR1 in the acid-stimulated formation and bone resorption of osteoclasts was also investigated. The results showed that in the pH 6.8 medium group the number of osteoclasts was 511.2±54.72 and the area of bone absorption was 4,184.88±277.14 µm2; both were significantly higher than those in the pH 7.4 medium group (all P<0.01). Inhibition of OGR1 using copper ion (Cu2+) reduced the number of osteoclasts and the area of bone resorption in the pH 6.8 medium group (all P<0.05). Furthermore, extracellular acid (pH 6.8) was able to induce a transient increase of Ca2+ levels in osteoclasts; however, inhibition of OGR1 using Cu2+ effectively attenuated the acid-induced increase of Ca2+ in osteoclasts. In addition, the elevation in Ca2+ levels was inhibited when BAPTA, a cytoplasmic Ca2+ chelator with cellular permeability, was added to the cells; however, the extracellular Ca2+-chelating agent ethylene glycol tetraacetic acid did not inhibit the acid-stimulated increase in Ca2+. Treatment with the phospholipase C inhibitor U73122 also inhibited the acid-stimulated increase of Ca2+ in osteoclasts. Furthermore, the mRNA expression levels of TRAP, matrix metalloproteinase-9, osteoclast-related receptor, nuclear factor-activated T cell 1 (NFATc1), cathepsin K and integrin β3 were elevated in the pH 6.8 medium group compared with those in the pH 7.4 medium group (all P<0.05). By contrast, the inhibition of OGR1 using Cu2+ partially reduced the effects of the acidic environment on osteoclast differentiation and activity-related gene expression (all P<0.05). In addition, the mRNA and protein expression levels of calcineurin were increased in osteoclasts in the pH 6.8 group compared with those in the pH 7.4 group (P<0.05), whereas blocking OGR1 suppressed the expression of acid-induced calcineurin. The mRNA expression levels of NFATc1 in osteoclasts were also increased in the pH 6.8 medium group compared with those in the pH 7.4 medium group (P<0.05). By contrast, the specific calcineurin inhibitor cyclosporine A significantly inhibited the acid-induced expression of NFATc1 in osteoclasts. In conclusion, the present study revealed that extracellular acidification may increase osteoclast differentiation and bone resorption activity. Furthermore, OGR1-mediated Ca2+ elevation could have a crucial role in osteoclasts by regulating the Ca2+-calcineurin-NFATc1 signaling pathway and downstream signaling.

Bone-seeking tumor cells alter bone material quality parameters on the nanoscale in mice

Bone metastases related to breast and prostate cancer present with multiple challenges and skeletal related events like fragility fractures impair the quality of life of the patients significantly. To determine local alterations in bone material quality with bone metastasis, we subjected murine tibial specimens, generated after intratibial injections of either RM1 prostate cancer cells or EO771 breast cancer cells into male and female mice respectively, to high-resolution imaging modalities. Small and wide-angle X-ray scattering showed unaltered mineral characteristics in the more osteosclerotic prostate cancer model, while the quantification of calcium weight percentage via backscattered electron microscopy determined minor differences along the perilacunar bone matrix. Further analyses of mineral and collagen characteristics were performed using Raman spectroscopy and focused ion beam electron microscopy. Our study indicates that alterations in nanochannel properties occur due to the presence of bone seeking tumor cells with more prevalent nanopores in the perilacunar matrix.

The role of glial cells missing 2 in induced pluripotent stem cell parathyroid differentiation

Glial cells missing 2 (GCM2) has been identified as an essential factor for parathyroid differentiation, and GCM2 silencing in parathyroid cells decreases calcium-sensing receptor (CaSR) expression. However, the role of GCM2 in parathyroid differentiation from induced pluripotent stem cells (iPSCs) is unclear. Here, we investigated the role of GCM2 in parathyroid differentiation from iPSCs using the Tet-On 3 G system. We confirmed that iPS cells transfected with GCM2/TRE3G and pCMV-Tet3G vectors express GCM2 in a doxycycline-dependent manner. Though parathyroid glands derive from the endoderm and differentiate via the third pharyngeal arch (PPE), overexpression of GCM2 in iPSCs significantly abolished the suppression of OCT4 and SOX2, suggesting inhibition of endodermal differentiation. GCM2 overexpression at the stage of differentiation into the third PPE also increased the expression levels of CaSR and parathyroid hormone, and increased the number of CaSR+/EpCAM+ cells. These results suggest that GCM2 regulates parathyroid differentiation after endoderm differentiation rather than at an earlier stage.

Construction of bilayer biomimetic periosteum based on SLA-3D printing for bone regeneration

An ideal biomimetic periosteum should have excellent biocompatibility to promote osteoclast adhesion and improve osseointegration, which is significant in promoting bone regeneration. In this work, a bionic artificial periosteum printed by the SLA-3D printing was prepared, consisting of a poly (ethylene glycol) diacrylate (PEGDA)/chitosan/tricalcium phosphate (TCP) fibrous layer and a gelatin methacryloyl (GelMA)/ammonium molybdate (Mo) cambium layer. Distinct surface characteristics were achieved on both sides of the biomimetic periosteum. Among them, the fibrous layer has high mechanical properties and low porosity, which is conducive to preventing the pulling of muscle tissues and the invasion of soft tissues. The cambium layer has a porous structure and bioactive factors that can effectively promote osteogenic differentiation of preosteoblasts. Combined with mild photothermal therapy triggered by NIR light, the biomimetic periosteum could promote bone regeneration at both the chemical and physical levels. This 3D-printed bilayer hydrogel can provide a promising strategy for preparing advanced tissue-engineered periosteum with excellent physical and bone regeneration properties.

The effects of pre-operative anti-osteoporotic use on total joint arthroplasty complications: A national database study

Background

The current study aims to analyze the effect of pre-operative non-bisphosphonate anti-osteoporotic drugs on complication and revision rates following total joint arthroplasty (TJA).

Methods

A retrospective cohort analysis of the PearlDiver (PearlDiver Technologies, Colorado Springs, CO) database was performed. The database was queried to identify all patients who underwent total hip arthroplasty (THA) or total knee arthroplasty (TKA) with history of hip or knee osteoarthritis and either osteopenia or osteoporosis. The treatment groups consisted of patients prescribed non-bisphosphonate and bisphosphonate osteomodulatory agents for 1 year prior to and following surgery. The treatment groups were matched to control cohorts by age, gender, and comorbidities. Chi-square analyses were used to compare outcomes between paired cohorts.

Results

There were no statistically significant differences (p ≤ 0.05) in risk of aseptic loosening, broken prosthesis, dislocation of prosthetic joint, periprosthetic fracture, periprosthetic osteolysis, postoperative infection, full or partial revision, or stress fracture between both the non-bisphosphonate and bisphosphonate groups following THA or TKA. Comparisons between both groups and control cohort also yielded no significant differences.

Conclusion

The current study detected no significant differences in early post-operative complications following TJA between patients treated with different classes of anti-osteoporotic medications versus untreated osteopenic/osteoporotic patients. Further research is required to fully understand the impact of osteomodulatory medications on TJA outcomes. Analysis should continue to ensure a high-quality standard of care and aim to better understand outcomes for such patients requiring TJA.

Automatic AI tool for opportunistic screening of vertebral compression fractures on chest frontal radiographs: A multicenter study

Vertebral compression fractures (VCFs) are the most common type of osteoporotic fractures, yet they are often clinically silent and undiagnosed. Chest frontal radiographs (CFRs) are frequently used in clinical practice and a portion of VCFs can be detected through this technology. This study aimed to develop an automatic artificial intelligence (AI) tool using deep learning (DL) model for the opportunistic screening of VCFs from CFRs. The datasets were collected from four medical centers, comprising 19,145 vertebrae (T6-T12) from 2735 patients. Patients from Center 1, 2 and 3 were divided into the training and internal testing datasets in an 8:2 ratio (n = 2361, with 16,527 vertebrae). Patients from Center 4 were used as the external test dataset (n = 374, with 2618 vertebrae). Model performance was assessed using sensitivity, specificity, accuracy and the area under the curve (AUC). A reader study with five clinicians of different experience levels was conducted with and without AI assistance. In the internal testing dataset, the model achieved a sensitivity of 83.0 % and an AUC of 0.930 at the fracture level. In the external testing dataset, the model demonstrated a sensitivity of 78.4 % and an AUC of 0.942 at the fracture level. The model's sensitivity outperformed that of five clinicians with different levels of experience. Notably, AI assistance significantly improved sensitivity at the patient level for both junior clinicians (from 56.1 % without AI to 81.6 % with AI) and senior clinicians (from 65.0 % to 85.6 %). In conclusion, the automatic AI tool significantly increases clinicians' sensitivity in diagnosing fractures on CFRs, showing great potential for the opportunistic screening of VCFs.

Scurvy incidence trend among children hospitalised in France, 2015-2023: a population-based interrupted time-series analysis

Background

Scurvy, historically rare in-high income countries, has re-emerged as an indicator of socioeconomic and dietary disparities. Limited data exist on scurvy trends among European children, particularly following socioeconomic changes since the COVID-19 pandemic. This study analysed scurvy incidence trends among French children over a nine-year period, examining potential post-pandemic increases.

Methods

This cohort study used an interrupted time-series analysis of patient records from a national hospital-based French surveillance system. All children aged <18 years hospitalized with scurvy and malnutrition from January 2015 to November 2023 were included. The monthly incidence of hospitalized scurvy per 100,000 children was analysed using a segmented linear regression model with autoregressive error. Incidence of hospitalization for malnutrition was analysed as secondary outcome and for urinary tract infection and vitamin D deficiency as control outcomes.

Findings

A total of 888 children were hospitalized with scurvy (median age, 11 years; interquartile range [IQR], 4-15; 431 boys [48.5%]). The COVID-19 pandemic in March 2020 was associated with a significant increase in scurvy incidence (cumulative increase, 34.5%; 95% confidence interval [CI], 12.7-56.3; p = 0.002) and severe malnutrition (cumulative increase, 20.3%; 95% CI, 10.7-29.9; p < 0.001). The increased incidence of scurvy was correlated with the rise in the consumer price index. In contrast, no change was found for the two control outcomes.

Interpretation

This study identifies a significant increase in scurvy and severe malnutrition post-COVID-19, associated with inflation and socioeconomic instability, emphasizing the urgent need for targeted nutritional support for at-risk paediatric populations.

Funding

None.

ciBAR1 loss in mice causes laterality defects, pancreatic degeneration, and altered glucose tolerance

Bin/Amphiphysin/Rvs (BAR) domains are highly conserved domains found in all eukaryotes. BAR domain proteins form crescent-shaped dimers that sense and sculpt curved lipid membranes and play key roles in various cellular processes. However, their functions in mammalian development are poorly understood. We previously demonstrated that Chibby1-interacting BAR domain-containing 1 (ciBAR1, formerly known as FAM92A) localizes to the ciliary base and plays a critical role in ciliogenesis. Here, we report ciliopathy phenotypes of ciBAR1-KO mice. We found that ∼28% of ciBAR1-KO mice show embryonic lethality because of randomized left-right asymmetry; the rest survive into adulthood with no gross morphological abnormalities. Histological assessments of ciliated tissues revealed exocrine pancreatic lesions. Although overall endocrine islet morphology appeared to be normal, ciBAR1-KO mice showed impaired glucose tolerance. Examination of ductal and islet cilia revealed that cilia number and length were significantly reduced in ciBAR1-KO pancreata. ciBAR1-KO MEFs also exhibited ciliary defects. Our findings indicate that ciBAR1 plays a critical role in ciliogenesis depending on the tissue and cell type in mice.

MR Imaging of Tumors and Tumor-Like Conditions of the Hip

The hip joint is home to a diverse range of neoplasms, as well as many pseudo lesions, including post-traumatic, infectious, and degenerative processes. Through careful evaluation of the clinical context, location, and imaging features, these entities can be distinguished, enabling accurate and efficient diagnosis. While not exhaustive, this article reviews a selection of benign, malignant, and non-neoplastic lesions affecting the hip bones, cartilage, and soft tissues, focusing on their notable imaging and pathologic features.

Immune microenvironment of cancer bone metastasis

Bone is a common and frequent site of metastasis in cancer patients, leading to a significant reduction in quality of life and increased mortality. Bone marrow, the primary site of hematopoiesis, also serves as both a primary and secondary lymphoid organ. It harbors and supports a diverse array of immune cells, thereby creating a distinct immune microenvironment. These immune cells engage in a range of activities, including anti-tumor, pro-tumor, or a combination of both, which influence the development and progression of bone metastases. Rapid advances in cancer immunotherapy have underscored its potential to eradicate bone metastases. However, clinical outcomes have not yet met expectations. To improve the efficacy of immunotherapy, it is crucial to gain a comprehensive and in-depth understanding of the immune microenvironment within bone metastases. This review provides an overview of the current understanding of the role of different immune cells, their anti-tumor and pro-tumor activities, and their overall contribution to bone metastasis.

ART26.12, a novel fatty acid-binding protein 5 inhibitor, shows efficacy in multiple preclinical neuropathy models

BACKGROUND

Painful neuropathy is a pathological condition caused by numerous factors including diabetes, chemotherapy or cancer. ART26.12 is a novel fatty acid-binding protein 5 inhibitor, which our group showed could prevent and treat persistent pain in a preclinical model of oxaliplatin-induced peripheral neuropathy.

METHODS

In the current study, the efficacy of orally dosed ART26.12 was tested in multiple neuropathy models of different aetiology. Paw withdrawal threshold to von Frey monofilaments and latency to escape a cold plate were used as measurements of mechanical and cold sensitivity.

RESULTS

ART26.12 (25 and 50 mg/kg BID), dosed prior to the induction of paclitaxel-induced peripheral neuropathy (PIPN), reversed mechanical allodynia induced by paclitaxel in both male and female rats, and ART26.12 (50 mg/kg BID) prevented the induction of PIPN in female rats. ART26.12 (50 mg/kg BID) also had a protective effect on body weight in the PIPN model. ART26.12 (25 and 100 mg/kg BID) reversed mechanical allodynia when treating established streptozotocin-induced diabetic neuropathy in male rats. In a model of breast cancer-induced bone pain in female rats, ART26.12 (100 mg/kg BID) reversed mechanical allodynia within 1 h of dosing. In the same model, ART26.12 (25 mg/kg BID) reversed mechanical allodynia from day 4 of treatment.

CONCLUSION

Overall, these preclinical data suggest that ART26.12 is a safe and efficacious therapeutic drug for continued development towards the prevention and treatment of peripheral neuropathy.

SIGNIFICANCE STATEMENT

This work now shows that ART26.12, a novel and selective inhibitor of FABP5, can prevent and treat multiple preclinical models of peripheral neuropathy. Given its excellent safety profile, further work is warranted to develop ART26.12 as a potential therapeutic tool for pain management.

The evolution of nutritional care in children and young people with acute lymphoblastic leukaemia: a narrative review

BACKGROUND

Acute lymphoblastic leukaemia (ALL) is the most common paediatric malignancy in the world. Advances in treatment protocols have resulted in survival rates of >80% in most high-income countries (HIC); however, children and young people (CYP) with ALL continue to face significant nutrition-related challenges during treatment.

METHODS

This narrative review outlines the changing landscape of treatment and survivorship for CYP with ALL and the advances in nutrition knowledge that call for changes to clinical nutrition practice.

RESULTS

The incidence of ALL has remained stable in HIC; however, there have been significant advances in survival over the past 30 years. Overweight and obesity are increasingly prevalent in CYP with ALL at diagnosis, during treatment and in survivorship. Coupled with poor diet quality, high-energy and saturated fat intakes, altered eating behaviours and inactivity, this necessitates the need for a shift in nutrition intervention. Undernutrition remains a concern for CYP with high-risk treatment protocols where oral or enteral nutrition support remains a cornerstone of maintaining nutrition status.

CONCLUSIONS

With improved treatment protocols and high survival rates, a shift to focusing on diet quality, prevention of excessive weight gain and obesity during treatment and survivorship is necessary.

Influence of cholecalciferol supplementation on changes in total 25OHD, free 25OHD, and free 25OHD % in relation to calcium, bone, and glucose homeostasis in young, infertile men

BACKGROUND AND OBJECTIVE

While all types of vitamin D metabolites are bound to vitamin D binding protein and albumin leaving only a small fraction in its free active form, only serum concentrations of total 25-hydroxy vitamin D (25OHD) are used to determine vitamin D status in clinical practice. This study aimed to describe the association of total 25-hydroxy vitamin D (25OHD), calculated free 25OHD, and free 25OHD% (free 25OHD × 100 %/total 25OHD) with mineral, bone, and metabolic variables and assess the impact of cholecalciferol supplementation.

RESEARCH DESIGN AND METHODS

Secondary data from a single-center, double-blinded, randomized, placebo-controlled clinical trial (NCT01304927) in 307 infertile men. The treatment group (n = 151) initially received 300,000 IU cholecalciferol as a bolus followed by 1400 IU daily for 150 days and was compared to a placebo group (n = 156).

RESULTS

At baseline men with free 25OHD% > 0.03 % had lower serum triglycerides (mmol/L) (0.8 vs. 1.0; p = 0.002), lower LDL (mmol/L) (2.7 vs. 3.1; p = 0.003), lower fasting blood glucose (mmol/L) (4.9 vs. 5.2; p = 0.012), and lower PTH (pmol/L) (3.8 vs. 4.6; p = 0.015) compared to men with free 25OHD% < 0.02 %. When the study population was stratified according to total 25OHD or free 25OHD, the metabolic markers and bone variables did not show any differences. Cholecalciferol supplementation increased total 25OHD after 150 days compared to placebo and the difference was highest in men with lowest vitamin D status. Cholecalciferol supplementation did not change free 25OHD%.

CONCLUSION

The free 25OHD% is better associated with metabolic health markers such as serum triglycerides, LDL, and fasting blood glucose, but not bone or calciotrophic markers except parathyroid hormone. The free 25OHD% is not affected by cholecalciferol supplementation.

Intraoperative Parathyroid Hormone Kinetics are Variable: An In-Vivo Analysis

OBJECTIVES

Intraoperative parathyroid hormone (IOPTH) monitoring has become routine in parathyroid surgery to facilitate less invasive techniques to treat hyperparathyroidism. Despite this, little is known about in vivo IOPTH kinetics, which can greatly affect the reliability of its interpretation.

METHODS

A prospective cohort of patients undergoing routine parathyroidectomy was studied. During each case, IOPTH was measured frequently, during all key perioperative events. Qualitative, univariate, and multivariate analysis was performed to better understand the patterns of in vivo IOPTH kinetics.

RESULTS

The IOPTH increased from preoperative baseline in every case, but some patients had a rapid spike after gland manipulation while others had a more gradual increase. The IOPTH peak occurred prior to excision in almost every case. The IOPTH began to fall prior to excision, typically returning to preoperative baseline levels just before excision. The average in vivo half-life of parathyroid hormone (PTH) was 5.2 minutes.

CONCLUSION

There is substantial variation in the in vivo IOPTH kinetics and more research is needed to understand predictors of kinetic patterns and PTH half-life during parathyroidectomy.

The Effect of Medical Status on Long-Term Survival of Dental Implants

Successful dental implant therapy relies on a bone-implant interface that is mechanically strong and capable of dynamic remodeling in response to functional loads. There are a number of medical conditions or therapies that can affect either bone metabolism or the resistance of bone to infection. However, their effects are often mitigated by local factors or individual responses so the impact of these conditions is not clear-cut. This article will review a number of these conditions and therapies and describe existing studies that have studied these conditions to guide practitioners in their implant practice.

Osteoprotegerin secretion and its inhibition by RANKL in osteoblastic cells visualized using bioluminescence imaging

Bone remodeling is regulated by the interaction between receptor activator of nuclear factor kappa-B ligand (RANKL) and its receptor RANK on osteoblasts and osteoclasts, respectively. Osteoprotegerin (OPG) is secreted from osteoblasts and inhibits osteoclast differentiation by acting as a decoy receptor for RANKL. Despite its importance, the mechanism underlying the secretion of OPG remains poorly understood. Here, we applied a method of video-rate bioluminescence imaging using a fusion protein with Gaussia luciferase (GLase) and visualized the secretion of OPG from living mouse osteoblastic MC3T3-E1 cells. The bioluminescence imaging revealed that the secretion of OPG fused to GLase (OPG-GLase) occurred frequently and widely across the cell surface. Notably, co-expression of RANKL significantly reduced the secretion of OPG-GLase, indicating an inhibitory role of RANKL on OPG secretion within cells. Further imaging and biochemical analyses using deletion mutants of OPG and RANKL, as well as RANKL mutants that cause autosomal recessive osteopetrosis, demonstrated the essential role of protein-protein interaction between OPG and RANKL in the inhibition of OPG secretion. Treatment with proteasome inhibitors resulted in increased levels of OPG in both culture medium and cell lysates. However, the fold-increase of OPG was similar regardless of the presence or absence of RANKL, suggesting that the regulation of OPG secretion by RANKL is independent of proteasome activity. This report visualized the secretion of OPG from living cells and provided evidence for a novel intracellular inhibitory effect of RANKL on OPG secretion.

Genes involved in osteogenic differentiation induced by low‑intensity pulsed ultrasound in goldfish scales

The teleost scale is a unique calcified tissue that contains osteoclasts, osteoblasts, osteocytes and the bone matrix, similar to mammalian bone. Here, the effects of low-intensity pulsed ultrasound (LIPUS) on osteoblasts and osteoclasts in goldfish scales were investigated. Scales were treated with LIPUS, which is equivalent to use under clinical conditions (30 mW/cm2 for 20 min), then cultured at 15˚C. Alkaline phosphatase activity, a marker of osteoblasts, or tartrate-resistant acid phosphatase (TRAP) activity, a marker of osteoclasts was measured. The gene expression profile was examined using RNA-sequencing. Gene network and biological function analyses were performed using the Ingenuity® Pathways Knowledge Base. A single exposure of LIPUS significantly increased ALP activity but did not affect TRAP activity. These data indicated that LIPUS induced osteoblastic activation in goldfish scales. Using RNA-sequencing, numerous genes that were significantly and differentially expressed 3, 6, and 24 h after LIPUS exposure were observed. Ingenuity® pathway analysis demonstrated that three gene networks, GN-3h, GN-6h, and GN-24h, were obtained from upregulated genes at 3, 6 and 24 h culture, respectively, and included several genes associated with osteoblast differentiation, such as protein kinase D1, prostaglandin-endoperoxide synthase 2, TNFRSF11B (tumor necrosis factor receptor superfamily, member 11b) and WNT3A (Wnt family member 3A). A significant upregulation of expression levels of these genes in scales treated with LIPUS was confirmed by reverse transcription-quantitative polymerase chain reaction. These results contribute to elucidating the molecular mechanisms of osteoblast activation induced by LIPUS.

Prediction of vertebral failure under general loadings of compression, flexion, extension, and side-bending

Bone pathologies such as osteoporosis and metastasis can significantly compromise the load-bearing capacity of the spinal column, increasing the risk of vertebral fractures, some of which may occur during routine physical activities. Currently, there is no clinical tool that accurately assesses the risk of vertebral fractures associated with these activities in osteoporotic and metastatic spines. In this paper, we develop and validate a quantitative computed tomography-based finite element analysis (QCT/FEA) method to predict vertebral fractures under general load conditions that simulate flexion, extension, and side-bending movements, reflecting the body's activities under various scenarios. Initially, QCT/FEA models of cadaveric spine cohorts were developed. The accuracy and verification of the methodology involved comparing the fracture force outcomes to those experimentally observed and measured under pure compression loading scenarios. The findings revealed a strong correlation between experimentally measured failure loads and those estimated computationally (R2 = 0.96, p < 0.001). For the selected vertebral specimens, we examined the effects of four distinct boundary conditions that replicate flexion, extension, left side-bending, and right side-bending loads. The results showed that spine bending load conditions led to over a 62% reduction in failure force outcomes compared to pure compression loading conditions (p ≤ 0.0143). The study also demonstrated asymmetrical strain distribution patterns when the loading condition shifted from pure compression to spine bending, resulting in larger strain values on one side of the bone and consequently reducing the failure load. The results of this study suggest that QCT/FEA can be effectively used to analyze various boundary conditions resembling real-world physical activities, providing a valuable tool for assessing vertebral fracture risks.

Use of osteogenic bone matrix in patients with traumatic long bone defects: An open label, single center study

Background

Osteogenic Bone Matrix (Altis™ OBM) is a tissue-engineered, porcine-derived demineralized bone matrix prepared using a humanization processing technology that confers biocompatibility and improved osteoinductivity. The objective of this study was to determine the safety and efficacy of OBM in patients with traumatic long bone defects in an open-label, non-randomized single-center study.

Methods

Diagnosis and main criteria for inclusion were open long bone fractures graded as Gustilo-Anderson Grade II, IIIA or IIIB. 24 participants were enrolled from one center, of which 17 were assigned to the investigational group (OBM) and 7 to the standard of care (SOC) group. Participants were followed at intervals of one, two, six, and 13 weeks to undergo physical examinations and record adverse events, vital signs, electrocardiograms, hematology, blood biochemistry and circulating humoral antibodies against human and porcine Type I and II collagens. Efficacy of treatment over six months post-surgery was assessed by a panel of blinded radiologists to determine the proportion of subjects with radiographic bridging of fractures in both the OBM efficacy group and the SOC group. Limb function, weight-bearing, pain and mobility at the fracture site were assessed by the investigator. Patient satisfaction with the treatment and quality of life were assessed using the SF 36 quality of life questionnaire.

Results

14 OBM patients and five SOC patients completed the first three months of the safety investigation. 10 OBM patients and four SOC patients completed the full six months of the efficacy investigation. Biochemical and hematological parameters were within normal ranges. The efficacy evaluation at six months indicated that 70 % of participants in the OBM group had bridging of the bone defect and 80 % were weight-bearing versus 50 % in the SOC group. The quality of life study demonstrated an increased level of satisfaction as compared with the baseline. Histological analysis of a single biopsy specimen at three months revealed bone regeneration activity within the implanted OBM.

Conclusions

The study showed that treatment with OBM was well tolerated in participants and there was no evidence of clinically relevant toxicity or immunological, biochemical, hematological or adverse reaction due to the use of OBM. There was better bridging in the OBM group versus SOC. Pharmacoeconomic analysis showed OBM to be cost-effective versus standard of care.

Trial registration

Medicines Control Council of South Africa (MCC number N2/19/8/2).

Bone marrow lesions in osteoarthritis: biomarker or treatment target? A narrative review

Osteoarthritis (OA) is a leading cause of pain, functional impairment, and disability in older adults. However, there are no effective treatments to delay and reverse OA. Magnetic resonance imaging (MRI) can assess structural abnormalities of OA by directly visualizing damage and inflammatory reactions within the tissues and detecting abnormal signals in the subchondral bone marrow region. While some studies have shown that bone marrow lesions (BMLs) are one of the early signs of the development of OA and predict structural and symptomatic progression of OA, others claimed that BMLs are prevalent in the general population and have no role in the progression of OA. In this narrative review, we screened and summarized studies with different designs that evaluated the association of BMLs with joint symptoms and structural abnormalities of OA. We also discussed whether BMLs may serve as an imaging biomarker and a treatment target for OA based on existing clinical trials.

New players in the landscape of renal cell carcinoma bone metastasis and therapeutic opportunities

Approximately one-third of advanced renal cell carcinoma (RCC) patients develop osteolytic bone metastases, leading to skeletal complications. In this review, we first provide a comprehensive perspective of seminal studies on bone metastasis of RCC describing the main molecular modulators and growth factor signaling pathways most important for the RCC-stimulated osteoclast-mediated bone destruction. We next focus on newer developments revealing with in-depth details, the bidirectional interplay between renal cancer cells and the immune and stromal microenvironment that can through epigenetic reprogramming, profoundly affect the behaviors of transformed cells. Understanding their mechanistic interactions is of paramount importance for advancing both fundamental and translational research. These new investigations into the landscape of RCC-bone metastasis offer novel insights and identify potential avenues for future therapeutic interventions.