Search Results (437)

Red blood cell (RBC) production from bone marrow hematopoietic stem cells (BMHSCs) in vitro overlooks the mechanical signals of the bone marrow niche and overly relies on growth factors. Considering that the fate of hematopoietic stem cells (HSCs) is determined by the natural bone marrow microenvironment, differences in mechanical microenvironments provide a reference for the regulation of HSC differentiation. This study seek to reveal the role of mechanobiology cues in erythropoiesis and provide a new perspective for the design of in vitro erythropoiesis platforms. The hydrogel platforms we designed simulate the stiffness gradient of the bone marrow niche to culture HSCs and induce their differentiation into the erythroid system. Cells on the low-stiffness scaffold have higher potential for erythrocyte differentiation and faster differentiation efficiency and promote erythrocyte differentiation after erythropoietin (EPO) restriction. In vivo transplantation experiments demonstrated that these cells have the ability for continuous proliferation and differentiation into mature erythrocytes. By combining mechanical cues with in vitro erythrocyte production, this method is expected to provide insights for in vitro hematopoietic design and offer a scalable cell manufacturing platform for transfusion medicine. Full article

Background: The relationship between spleen and bone marrow stiffness, and other features of abnormal myeloproliferation has long been described. However, the scientific knowledge in this area remains very superficial. This review evaluated the diagnostic effectiveness of various ultrasound (US) methods in the assessment of neoplastic myeloproliferation using spleen stiffness measurement (SSM). Aim: To explore the diagnostic accuracy of US techniques in assessing spleen stiffness, determining which of them may be suitable for the diagnosis of myeloproliferative diseases in adults. Methods: The review included original retrospective or prospective studies published in the last five years (2019–2024) in peer-reviewed medical journals that reported receiver operating characteristics (ROCs) for SSM and the articles concerning the relation between SSM values and neoplastic myeloproliferation. The studies were identified through PubMed searches on 1 July and 1 December 2024. Quality was assessed using the QUADAS-2 tool. Results were tabulated according to the diagnostic method separately for myeloproliferative neoplasms (MNs) and for other clinical findings. Results: The review included 52 studies providing ROCs for SSM or compatibility between operators, and five studies covering the relation between SSM values and MNs. Conclusions: Acoustic radiation force impulse (ARFI), two-dimensional shear wave elastography (2D-SWE), transient elastography (TE), and point shear wave elastography (p-SWE) are promising methods for measuring SSM that can be incorporated into the diagnosis, screening, and monitoring system in MNs. Full article

Background and Objectives: Magnesium (Mg)-based materials, such as the WE43 alloy, show potential in biomedical applications owing to their advantageous mechanical properties and biodegradability; however, their quick corrosion rate and hydrogen release restrict their general clinical utilization. This study aimed to develop a novel Mg-Zn-Ca alloy system based on WE43 alloy, evaluating the influence of Zn and Ca additions on microstructure, mechanical properties, cytocompatibility, and electrochemical behavior for potential use in biodegradable orthopedic applications. Materials and Methods: The WE43-Zn-Ca alloy system was developed by alloying standard WE43 (Mg–Y–Zr–RE) with 1.5% Zn and Ca concentrations of 0.2% (WE43_0.2Ca alloy) and 0.3% (WE43_0.3Ca alloy). Microstructural analysis was performed utilizing scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS), while the chemical composition was validated through optical emission spectroscopy and X-ray diffraction (XRD). Mechanical properties were assessed through tribological tests. Electrochemical corrosion behavior was evaluated using potentiodynamic polarization in a 3.5% NaCl solution. Cytocompatibility was assessed in vitro on MG63 cells using cell viability assays (MTT). Results: Alloys WE43_0.2Ca and WE43_0.3Ca exhibited refined, homogeneous microstructures with grain sizes between 70 and 100 µm, without significant structural defects. Mechanical testing indicated reduced stiffness and an elastic modulus similar to human bone (19.2–20.3 GPa), lowering the risk of stress shielding. Cytocompatibility tests confirmed non-cytotoxic behavior for alloys WE43_0.2Ca and WE43_0.3Ca, with increased cell viability and unaffected cellular morphology. Conclusions: The study validates the potential of Mg-Zn-Ca alloys (especially WE43_0.3Ca) as biodegradable biomaterials for orthopedic implants due to their favorable combination of mechanical properties, corrosion resistance, and cytocompatibility. The optimization of these alloys contributed to obtaining an improved microstructure with a reduced degradation rate and a non-cytotoxic in vitro outcome, which supports efficient bone tissue regeneration and its integration into the body for complex biomedical applications. Full article

Background/Objectives: Increasing evidence suggests that metabolic dysfunction-associated steatotic liver disease (MASLD) and hypertension (HTN), a well-established cardiometabolic risk factor, both negatively impact bone metabolism. This study aimed to investigate the associations between bone turnover markers (BTMs)—namely, osteopontin (OPN) and procollagen type 1 N-terminal propeptide (P1NP)—and metabolic health indicators, non-invasive measures of liver disease severity, as well as skeletal muscle mass (SMM), muscle strength, and bone mineral density (BMD) in patients with MASLD and HTN. Methods: We enrolled 117 patients diagnosed with MASLD and HTN and conducted anthropometric measurements, laboratory analyses, abdominal ultrasound, and point shear-wave elastography. Muscle strength was evaluated using grip strength measurements and the Five Times Sit-to-Stand Test (FTSST). SMM and BMD were quantified using dual-energy X-ray absorptiometry (DEXA). Serum OPN and P1NP concentrations were quantified using enzyme-linked immunosorbent assays (ELISAs). Results: Serum OPN concentrations below 2.89 ng/mL were associated with significantly elevated levels of AST (p = 0.001), ALT (p = 0.006), and GGT (p = 0.025), while serum P1NP concentrations above 47.5 pg/mL were associated only with significantly elevated GGT levels (p = 0.024). In addition, patients with MASLD and HTN with lower serum OPN levels had higher liver stiffness values (p = 0.003). Serum OPN concentrations were inversely associated with the following metabolic health indicators: waist circumference (WC, p < 0.001) and epicardial fat thickness (EFT, p = 0.001). In addition, they were significantly elevated in patients with MASLD and HTN who had decreased spinal BMD (p = 0.017). In turn, serum P1NP levels were reduced in patients with decreased SMM (p = 0.023). Conclusions: These findings in patients with MASLD and HTN suggest an association between serum P1NP levels and SMM, and between OPN levels and spinal BMD, indicating a potential interplay among liver function, muscle mass, and bone health. Furthermore, OPN appeared to be strongly associated with overall metabolic health indicators, such as WC and EFT, whereas P1NP exhibited a stronger association with muscle mass. Full article

Hepatosplenomegaly can occur in extrahepatic diseases such as Philadelphia-negative chronic myeloproliferative neoplasms (MPNs), which may involve the liver and vasculature. In myelofibrosis, extramedullary hematopoiesis can be present in the liver, even within hepatic sinusoids. Liver biopsies in MPN patients have shown platelet aggregates obstructing these sinusoids. Both liver and spleen stiffness are significantly higher in myelofibrosis, correlating with the severity of bone marrow fibrosis. Spleen stiffness is also elevated in myelofibrosis and polycythemia Vera compared to essential thrombocythemia. MPNs are a leading cause of splanchnic vein thrombosis in the absence of cirrhosis or local malignancy, especially in the presence of the JAK2V617F mutation. This mutation promotes thrombosis through endothelial dysfunction and inflammation. It is found in endothelial cells, where it enhances leukocyte adhesion and upregulates thrombogenic and inflammatory genes. Hepatic sinusoidal microthromboses in MPNs may contribute to portal hypertension and liver dysfunction. MPN therapies can also affect liver function. While hepatocytolysis has been reported, agents such as Hydroxycarbamide and Ruxolitinib exhibit antifibrotic hepatic effects in experimental models. Overall, MPNs are linked to chronic inflammation, increased thrombotic risk—particularly splanchnic thrombosis—and atherogenesis. Full article

Advancements in load-bearing tissue repair increasingly demand biomaterials that not only support structural integrity but also interact dynamically with the physiological environment. This review examines the latest progress in smart biomaterials designed for skeletal reconstruction, with emphasis on mechanoresponsive scaffolds, bioactive composites, and integrated microsensors for real-time monitoring. We explore material formulations that enhance osseointegration, resist micromotion-induced loosening, and modulate inflammatory responses at the bone–implant interface. Additionally, we assess novel fabrication methods—such as additive manufacturing and gradient-based material deposition—for tailoring stiffness, porosity, and degradation profiles to match host biomechanics. Special attention is given to sensor-augmented platforms capable of detecting mechanical strain, biofilm formation, and early-stage implant failure. Together, these technologies promise a new class of bioresponsive, diagnostic-capable constructs that extend beyond static support to become active agents in regenerative healing and post-operative monitoring. This multidisciplinary review integrates insights from materials science, mechanobiology, and device engineering to inform the future of implantable systems in skeletal tissue repair. Full article

Understanding the complex mechanical behavior of osteochondral tissues in silico is essential for improving experimental models and advancing research in joint health and degeneration. This review provides a comprehensive analysis of the constitutive models currently used to represent the different layers of the osteochondral region, from articular cartilage to subchondral bone, including intermediate regions such as the tidemark and the calcified cartilage layer. Each layer exhibits unique structural and mechanical properties, necessitating a layer-specific modeling approach. Through critical comparison of existing mathematical models, the viscoelastic model is suggested as a pragmatic starting point for modeling articular cartilage zones, the tidemark, and the calcified cartilage layer, as it captures essential time-dependent behaviors such as creep and stress relaxation while ensuring computational efficiency for initial coupling studies. On the other hand, a linear elastic model was identified as an optimal starting point for both the subchondral bone plate and the subchondral trabecular bone, reflecting their dense and stiff nature, and providing a coherent framework for early-stage multilayer integration. This layered modeling approach enables the development of physiologically coherent and computationally efficient representations of osteochondral region modeling. Furthermore, by establishing a layer-specific modeling approach, this review paves the way for modular in silico simulations through the coupling of computational models. Such an integrative framework supports scaffold design, in vitro experimentation, preclinical validation, and the mechanobiological exploration of osteochondral degeneration and repair. These efforts are essential for deepening our understanding of tissue responses under both physiological and pathological conditions. Ultimately, this work provides a robust theoretical foundation for future in silico and in vitro studies aimed at advancing osteochondral tissue regeneration strategies. Full article

Objective: Growth retardation in adolescents caused by nutritional deficiency requires effective intervention. A novel dietary supplement containing bamboo shoot extract, amino acids, and calcium citrate (Kidtal + Ca, KDTCa) was evaluated for its growth-promoting effects. Methods: After acclimatization, sixty-three 3-week-old male Sprague-Dawley (SD) rats were randomly divided into a normal control group and model groups. Growth retardation was induced in the modeling groups through calcium-deficient feeding, followed by administration of KDTCa, bamboo shoot extract and amino acids (Kidtal), or calcium citrate (CC). After 6 weeks of intragastric administration, the mechanical properties, microstructure, and growth plate development of bone were evaluated using three-point bending, micro-CT, and H&E staining, respectively. Bone calcium/phosphorus distribution and fecal calcium apparent absorption rate were measured by ICP-MS. Results: All inter-group differences were analyzed using one-way analysis of variance and checked using the Tuckey test. KDTCa treatment dose-dependently enhanced bone development in calcium-deficient rats. Compared to the model group, H-KDTCa significantly restored naso-anal length (p < 0.05) and body weight (p < 0.01). KDTCa supplementation significantly restored calcium and phosphorus levels in blood and bone. Three-point bending experiments showed that the stiffness and bending energy were increased by 142.58% and 384.7%. In bone microarchitecture, both bone mineral density (BMD) and microstructural parameters were significantly improved. These findings were consistent with the increased long bone length (p < 0.05) and decreased serum BALP/TRACP levels (p < 0.001). Dose-dependent IGF-1 elevation (p < 0.01) potentially mediated growth plate elongation by 35.34%. Notably, KDTCa increased calcium apparent absorption by 6.1% versus calcium-only supplementation at equal intake. Conclusions: KDTCa improves bone microstructure and strength, restores bone metabolism, and enhances growth plate height via promoting IGF-1 secretion to facilitate bone development. Further studies are needed to determine whether the components and calcium in Kidtal have a synergistic effect. Full article

Critical-sized bone defects or CSDs result from bone loss due to trauma, tumor removal, congenital defects, or degenerative diseases. Though autologous bone transplantation is the current gold standard in treating CSDs, its limitations include donor-site morbidity, unavailability of donor bone tissues, risk of infection, and mismatch between the bone geometry and the defect site. Customized scaffolds fabricated using 3D printing and biocompatible materials can provide mechanical integrity and facilitate osseointegration. Ti-6Al-4V (Ti64) is one of the most widely used commercial alloys in orthopedics. To avoid elastic modulus mismatch between bones and Ti64, it is imperative to use porous lattice structures. Ti64 scaffolds with diamond, cubic, and triply periodic minimal surface (TPMS) gyroid lattice architectures were fabricated using selective laser melting (SLM)with pore sizes ranging from 300 to 900 μm using selective laser melting and evaluated for mechanical and biological performance. Increasing pore size led to higher porosity (up to 90.54%) and reduced mechanical properties. Young’s modulus ranged from 13.18 GPa to 1.01 GPa, while yield stress decreased from 478.16 MPa to 14.86 MPa. Diamond and cubic scaffolds with 300–600 μm pores exhibited stiffness within the cortical bone range, while the 900 μm diamond scaffold approached trabecular stiffness. Gyroid scaffolds (600–900 μm) also showed modulus and yield strength within the cortical bone range but were not suitable for trabecular applications due to their higher stiffness. Cytocompatibility was confirmed through leachate analysis and DAPI-stained osteoblast nuclei. The biological evaluation reported maximum cell adherence in lower pore sizes, with gyroid scaffolds showing a statistically significant (p < 0.01) increase in cell proliferation. These findings suggest that 300–600 μm lattice scaffolds offer an optimal balance between mechanical integrity and biological response for load-bearing bone repair. Full article

The success of orthopedic implants critically depends on achieving mechanical and biological compatibility with bone tissue. Traditional titanium implants often suffer from high stiffness, which induces stress shielding, a phenomenon that compromises implant integration and accelerates prosthetic loosening. This study introduces an innovative approach to mitigate these limitations by engineering a porous titanium substrate with a controlled microstructure. Utilizing sodium chloride as a spacer holder, an elution and sintering process was applied at 1250 °C under high vacuum conditions to reduce the material’s elastic modulus. By manipulating NaCl volume fractions (20%, 25%, 30%, and 35%), porous titanium samples were created with elastic moduli between 16.37 and 22.56 GPa, closely matching cortical bone properties (4 to 20 GPa). A hydroxyapatite coating applied via plasma thermal spraying further enhanced osseointegration of the material. Comprehensive characterization through X-ray diffraction, scanning electron microscopy, and compression testing validated the material’s structural integrity. In vitro cytotoxicity assessments using osteoblast cells demonstrated exceptional cell viability exceeding 70%, confirming the material’s biocompatibility. These findings represent a significant advancement in biomaterial design, offering a promising strategy for developing next-generation joint prostheses with superior mechanical and biological adaptation to bone tissue. Full article

External fixators are frequently used to treat complex fractures with multiple bone fragments and soft tissue injuries. Inaccurate assessment of bone union and premature removal of the fixator may necessitate revisions and prolong treatment. The decision to remove an external fixator typically depends on an orthopedist’s experience. The accuracy of diagnosis can be improved by using a force sensor integrated into the modified external fixator according to Mitkovic. A sensor measuring axial compressive force is mounted between two vertical rods. Experiments with the modified external fixator were carried out using three different axial loads delivered by the universal electromechanical testing machine (UETM) and a sensor that detected the corresponding axial force. Springs with variable rigidity were used to simulate bone callus stiffness. Low rigidity springs represented a high elasticity callus, whereas high rigidity springs represented a callus with lower elasticity. The results show that the force detected by the sensor was nearly identical to the force delivered by the UETM while the callus did not form, decreased as spring rigidity increased, and eventually zeroed out as the leg healed. The findings indicated that using modified external fixator according to Mitkovic can help orthopedists assess bone healing more accurately. Full article

This study explores the rheological performance of bitumen modified with a synthetic polymer (styrene–butadiene–styrene, SBS) and two environmentally sustainable additives—animal bone ash (AB) and waste cooking oil (WCO)—to enhance durability and deformation resistance under dynamic loading. Frequency sweep and linear amplitude sweep (LAS) tests were conducted to evaluate viscoelastic and fatigue behavior. SBS at 5% showed the highest elasticity and fatigue life, making it optimal for heavily trafficked pavements. Among bio-waste additives, 6% AB provided the highest stiffness and rutting resistance in laboratory tests; however, 5% AB offered a better balance between structural integrity and cracking resistance, making it more suitable for general pavement applications. WCO-modified binders demonstrated improved flexibility, with 4% WCO achieving the best balance between elasticity and softening, ideal for low-load or temperate environments. These results highlight the potential of combining synthetic and bio-based waste materials to tailor bitumen properties for sustainable and climate-responsive pavement design. Full article

Background: Bone elasticity is one of the most important biomechanical parameters of the skeleton. It varies markedly with age, anatomical zone, bone type (cortical or trabecular) and bone marrow status. Methods: This review presents the result of a systematic review and analysis of 495 experimental and analytical papers on the elastic properties of bone tissue. The bone characteristics of hip, shoulder, skull, vertebrae as a function of the factors of age (young and old), sex (male and female), presence/absence of bone marrow and different test methods are examined. The Bayesian neural network (BNN) was used to estimate the uncertainty in some skeletal parameters (age, sex, and body mass index) in predicting bone elastic modulus. Results: It was found that the modulus of elasticity of cortical bone in young people is in the range of 10–30 GPa (depending on the type of bone), and with increasing age, this slightly decreases to 10–25 GPa, while trabecular tissue varies from 0.2 to 5 GPa and reacts more acutely to osteoporosis. Bone marrow, according to several studies, is able to partially increase stiffness under impact loading, but its contribution is minimal under slow deformations. Conclusions: BNN confirmed high variability, supplementing the predictions with confidence intervals and allowed the formation of equations for the calculation of bone tissue elastic modulus for the subsequent selection of the recommended elastic modulus of the finished implant, taking into account the biomechanical characteristics of bone tissue depending on age (young and old), sex (men and women) and anatomical zones of the human skeleton. Full article

Background: Stress shielding (SS) after total hip arthroplasty (THA) leads to proximal femoral bone loss and increases the risk of complications such as implant loosening and periprosthetic fracture. While various low-stiffness stems have been developed to prevent SS, they often compromise mechanical stability. A novel femoral stem composed of Ti-33.6Nb-4Sn (TNS) alloy offers a gradually decreasing Young’s modulus from proximal to distal regions, potentially improving load distribution and reducing SS. This study aimed to evaluate the mid-term clinical and radiographic outcomes of the TNS stem, with a particular focus on its effectiveness in suppressing SS. Methods: A prospective clinical study was conducted involving 35 patients who underwent THA using the TNS stem, with a minimum follow-up of 7 years. Twenty-one patients with Ti6Al4V metaphyseal-filling stems served as controls. Clinical outcomes were assessed using Japanese Orthopaedic Association (JOA) scores, and radiographic SS was graded using Engh’s classification and analyzed in Gruen zones. Inter-examiner reliability and statistical comparisons between groups were performed using appropriate tests. Results: The TNS group showed significantly higher preoperative JOA scores than the control group, but no significant difference in final scores. Both groups demonstrated significant improvement postoperatively. Third-degree SS occurred in the TNS group, although the overall SS grade distribution was significantly lower than in the control group (p = 0.03). SS frequency was significantly reduced in Gruen Zones 2, 3, and 6 in the TNS group. Conclusions: The TNS stem demonstrated a significant reduction in SS progression compared to conventional titanium stems over a 7-year period, with comparable clinical outcomes. However, the occurrence of third-degree SS indicates that material optimization alone may be insufficient, highlighting the need for further design improvements. Full article

Background/Objectives: Biomineral adhesive bone adhesives composed of phosphoserine combined with magnesium oxides or phosphates exhibit exceptional adhesive properties. This study evaluates two experimental mineral–organic cementitious adhesives in a clinical test setup, investigating their potential for fracture reduction and simultaneous defect filling. Methods: The two experimental adhesives (Groups B and C) and a standard hydroxyapatite cement (Group A, reference) underwent compressive strength testing, shear strength testing, and screw pullout tests as part of a first biomechanical characterization. Furthermore, all materials were tested in a porcine tibial split depression fracture model, where they served both for fracture reduction and for filling the metaphyseal bone defect, supplementary to plate osteosynthesis. Fracture stability was assessed under cyclic loading in a materials testing machine. Results: The OPLS (O-phospho-L-serine) containing adhesive (Group B) demonstrated the highest compressive strength as well as the highest shear strength. All three materials showed comparable maximum pullout forces. Both experimental adhesives (Groups B and C) exhibited higher pullout stiffness compared to the standard cement (Group A). In the fracture model, no significant differences in displacement under cyclic loading were observed between groups. Conclusions: The biomineral adhesive bone adhesives (Groups B and C) demonstrated biomechanical advantages in axial compression, adhesive (shear) strength, and screw fixation compared to the standard hydroxyapatite cement (Group A). Furthermore, they achieved comparable stabilization of metaphyseal fractures under clinically relevant dynamic loading conditions. Full article