bluuebunny/crossref_metadata_2025_split huggingface dataset:
LATERAL RIM VARIABLE ANGLE LOCKED PLATING VERSUS TENSION BAND WIRING OF SIMPLE AND COMPLEX PATELLA FRACTURES: A BIOMECHANICAL STUDY
Authors: Zderic I. , Warner S. , Stoffel K. , Woodburn W. , Castle R. , Penman J. , Saura-Sanchez E. , Helfet D.L. , Gueorguiev B. , Sommer C. 
Published: January 2024

Treatment of both simple and complex patella fractures is a challenging clinical problem. The aim of this study was to investigate the biomechanical performance of recently developed lateral rim variable angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.Twelve pairs of human anatomical knees were used to simulate either two-part transverse simple AO/OTA 34C1 or five-part complex AO/OTA 34C3 patella fractures by means of osteotomies, with each fracture model created in six pairs. The complex fracture pattern was characterized by a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral, and an inferior fragment mimicking comminution around the distal patellar pole. The specimens with simple fractures were pairwise assigned for fixation with either tension band wiring through two parallel cannulated screws, or a lateral rim variable angle locking plate. The knees with complex fractures were pairwise treated with either tension band wiring through two parallel cannulated screws plus circumferential cerclage wiring, or a lateral rim variable angle locking plate.Each specimen was tested over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive knee flexion within the range of 90° flexion to full knee extension. Interfragmentary movements were captured via motion tracking.For both fracture types, the longitudinal and shear articular displacements measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following the lateral rim variable angle locked plating compared with tension band wiring, p<0.01.Lateral rim locked plating of both simple and complex patella fractures provides superior construct stability versus tension band wiring under dynamic loading.
GEOMETRIC CONTROL OF BONE TISSUE GROWTH AND ORGANIZATION
Authors: Callens S.J.P. , Burdis R. , Cihova M. , Kim J.A. , Lau Q.Y. , Stevens M. M. 
Published: January 2024

Cells typically respond to a variety of geometrical cues in their environment, ranging from nanoscale surface topography to mesoscale surface curvature. The ability to control cellular organisation and fate by engineering the shape of the extracellular milieu offers exciting opportunities within tissue engineering. Despite great progress, however, many questions regarding geometry-driven tissue growth remain unanswered.Here, we combine mathematical surface design, high-resolution microfabrication, in vitro cell culture, and image-based characterization to study spatiotemporal cell patterning and bone tissue formation in geometrically complex environments. Using concepts from differential geometry, we rationally designed a library of complex mesostructured substrates (101-103 µm). These substrates were accurately fabricated using a combination of two-photon polymerisation and replica moulding, followed by surface functionalisation. Subsequently, different cell types (preosteoblasts, fibroblasts, mesenchymal stromal cells) were cultured on the substrates for varying times and under varying osteogenic conditions. Using imaging-based methods, such as fluorescent confocal microscopy and second harmonic generation imaging, as well as quantitative image processing, we were able to study early-stage spatiotemporal cell patterning and late-stage extracellular matrix organisation. Our results demonstrate clear geometry-dependent cell patterning, with cells generally avoiding convex regions in favour of concave domains. Moreover, the formation of multicellular bridges and collective curvature-dependent cell orientation could be observed. At longer time points, we found clear and robust geometry-driven orientation of the collagenous extracellular matrix, which became apparent with second harmonic generation imaging after ∼2 weeks of culture.Our results highlight a key role for geometry as a cue to guide spatiotemporal cell and tissue organisation, which is relevant for scaffold design in tissue engineering applications. Our ongoing work aims at understanding the underlying principles of geometry-driven tissue growth, with a focus on the interactions between substrate geometry and mechanical forces.
IMMUNOMODULATORY POTENTIAL OF MAGNETICALLY ASSISTED CELL SHEET UNDER HYPOXIC ENVIRONMENTS UPON MAGNETIC STIMULATION
Authors: Vinhas A. , Rodrigues M.T. , Gonçalves A.I. , Gomes M.E. 
Published: January 2024

Common tendon injuries impair healing, leading to debilitation and an increased re-rupture risk. The impact of oxygen-sensing pathways on repair mechanisms, vital in regulating inflammation and fibrosis, remains unclear despite their relevance in tendon pathologies. Recent studies show that pulsed electromagnetic field (PEMF) reduce inflammation in human tendon cells (hTDCs) and in hypoxia-induced inflammation. We investigated the hypoxia's impact (1% and 2% oxygen tension) using magnetic cell sheet constructs (IL-1β-magCSs) primed with IL-1β. IL-1β-magCSs were exposed to low OT (1h, 4h,6h) in a hypoxic chamber. To confirm the role of PEMF (5Hz, 4mT, 50% duty cycle) on hypoxia modulation, IL-1β-magCSs, previously exposed to OT, were 1h-stimulated with PEMF. Our results show a significant increase in HIF- 1a and HIF-2a expression on IL-1β-magCSs after exposure to 2%-OT at all time points, compared to 1%- OT and normoxia. TNFa, IL-6, and IL-8 expression increased after 6 hours of 1%-OT exposure. PEMF stimulation of hypoxic IL-1β-magCSs led to decreased pro-inflammatory genes and increased anti-inflammatory (IL-4,IL-10) expression compared to unstimulated magCSs. IFN-g, TNF-α, and IL-6 release increased after 6 hours, regardless of %-OT, while IL-10 levels tended to rise after PEMF stimulation at 2%-OT. Also, NFkB expression was increased on IL-1β-magCSs exposed to 4 h and 6 h of 2%-OT, suggesting a link between NFkB and the production of pro-inflammatory factors. Moreover, PEMF stimulation showed a significantly decreased NFkB level in IL-1β-magCSs.Overall, low OT enhances expression of hypoxia-associated genes and inflammatory markers in IL-1β-magCSs with the involvement of NFkB. PEMF modulates the response of magCSs, previously conditioned to hypoxia and to inflammatory triggers, favouring expression of anti-inflammatory genes and proteins, supporting PEMF impact in pro-regenerative tendon strategies.Acknowledgements: ERC CoG MagTendon(No.772817), FCT under the Scientific Employment Stimulus-2020.01157.CEECIND. Thanks to Hospital da Prelada for providing tendon tissue samples (Portugal), and TERMRES Hub (Norte-01-0145-FEDER-022190).
FATIGUE LIFE PREDICTION OF 3D-PRINTED POROUS TITANIUM IMPLANTS USING VALIDATED FINITE ELEMENT ANALYSES
Authors: Vautrin A. , Aw J. , Attenborough E. , Varga P. 
Published: January 2024

Although 3D-printed porous dental implants may possess improved osseointegration potential, they must exhibit appropriate fatigue strength. Finite element analysis (FEA) has the potential to predict the fatigue life of implants and accelerate their development. This work aimed at developing and validating an FEA-based tool to predict the fatigue behavior of porous dental implants.Test samples mimicking dental implants were designed as 4.5 mm-diameter cylinders with a fully porous section around bone level. Three porosity levels (50%, 60% and 70%) and two unit cell types (Schwarz Primitive (SP) and Schwarz W (SW)) were combined to generate six designs that were split between calibration (60SP, 70SP, 60SW, 70SW) and validation (50SP, 50SW) sets.Twenty-eight samples per design were additively manufactured from titanium powder (Ti6Al4V). The samples were tested under bending compression loading (ISO 14801) monotonically (N=4/design) to determine ultimate load (Fult) (Instron 5866) and cyclically at six load levels between 50% and 10% of Fult (N=4/design/load level) (DYNA5dent). Failure force results were fitted to F/Fult = a(Nf)b (Eq1) with Nf being the number of cycles to failure, to identify parameters a and b. The endurance limit (Fe) was evaluated at Nf = 5M cycles. Finite element models were built to predict the yield load (Fyield) of each design. Combining a linear correlation between FEA-based Fyield and experimental Fult with equation Eq1 enabled FEA-based prediction of Fe.For all designs, Fe was comprised between 10% (all four samples surviving) and 15% (at least one failure) of Fult. The FEA-based tool predicted Fe values of 11.7% and 12.0% of Fult for the validation sets of 50SP and 50SW, respectively. Thus, the developed FEA-based workflow could accurately predict endurance limit for different implant designs and therefore could be used in future to aid the development of novel porous implants.Acknowledgements: This study was funded by EU's Horizon 2020 grant No. 953128 (I-SMarD). We gratefully acknowledge the expert advice of Prof. Philippe Zysset.
DOES LOWER EXTREMITY SKELETAL MUSCLE MASS DETERMINE OSTEOARTHRITIS RISK?
Authors: Özer Y.P. , Karaduman D. , Karanfil Y. , Çiftçi E. , Balci C. , Doğu B.B. , Halil M.G. , Cankurtaran M. , Korkusuz F. 
Published: January 2024

Osteoarthritis (OA) of the knee joint is a complex peripheral joint disorder with multiple risk factors. We aimed to examine the relationship between the grade of knee OA and anterior thigh length (ATL).A total of 64 geriatric patients who had no total hip or knee replacement with a BMI of ≥30 were evaluated. Patients' OA severity was determined by two independent experts from bilateral standing knee radiographs according to the Kellgren-Lawrence (KL) grade. Joint cartilage structure was assessed using ultrasonography (US). The ATL, the gastrocnemius medialis (GC), the rectus femoris (RF) and the rectus abdominis (RA) skeletal muscle thicknesses as well as the RF cross-sectional area (CSA) were measured with US. Sarcopenia was diagnosed using the handgrip strength (HGS), 5× sit-to-stand test (5xSST) and bioelectrical impedance analysis.The median (IQR) age of participants was 72 (65–88) years. Seventy-one per cent of the patients (n=46) were female. They were divided into the sarcopenic obese (31.3 %) and the non-sarcopenic obese (68.8%) groups. KL grade of all patients correlated negatively with the ATL (mm) and the thickness of GC (mm) (r= -0,517, p<0.001 and r= -0.456, p<0.001, respectively). In the sarcopenic obese and the non-sarcopenic obese groups, KL grade of the all patients was negatively correlated with ATL (mm) and thickness of GC (mm) (r= -0,986, p<0.001; r= -0.456, p=0.05 and r= -0,812, p=0.002; r= −0,427, p=0.006). KL grade negatively correlated with the RF thickness in the sarcopenic obese group (r= -0,928, p=0.008).In conclusion, OA risk may decrease as the lower extremity skeletal muscle mass increases.Acknowledgments: Feza Korkusuz MD is a member of the Turkish Academy of Sciences (TÜBA).
EXTRACELLULAR VESICLES SECRETED BY OSTEOGENIC-DIFFERENTIATED MESENCHYMAL STEM CELLS PROMOTE BONE FORMATION IN RAT CALVARIAL DEFECT
Authors: Al-Sharabi N. 
Published: January 2024

Growing evidence has suggested that paracrine mechanisms of Mesenchymal stem cell (MSC) may be involved in the underlying mechanism of MSC after transplantation, and extracellular vesicles (EVs) are an important component of this paracrine role. The aim of this study was to investigate the in vitro osteogenic effects of EVs derived from undifferentiated mesenchymal stem cells and from chemically induced to differentiate into osteogenic cells for 7 days. Further, the osteoinductive potential of EVs for bone regeneration in rat calvarial defects was assessed.We could isolate and characterize EVs from naïve and osteogenic-induced MSCs. Proteomic analysis revealed that EVs contained distinct protein profiles, with Osteo-EVs having more differentially expressed proteins with osteogenic properties. EVs were found to enhance the proliferation and migration of cultured MSC. In addition, the study found that Osteo-EVs/MEM combination scaffolds could enhance greater bone formation after 4 weeks as compared to native MEM loaded with serum-free media.The study suggests that EVs derived from chemically osteogenic-induced MSCs for 7 days can significantly enhance both the osteogenic differentiation activity of cultured hMSCs and the osteoinductivity of MEM scaffolds. The results indicate that Osteo-MSC-secreted nanocarriers-EVs combined with MEM scaffolds can be used for repairing bone defects.
INVESTIGATION OF INTERVERTEBRAL DISC HERNIATION THROUGH A HUMAN ANULUS FIBROSUS PRO-INFLAMMATORY MODEL
Authors: Castro A.L. , Barbosa M.A. , Gonçalves R.M. 
Published: January 2024

Intervertebral disc (IVD) herniation involves a chronic inflammatory process and failure of the annulus fibrosus (AF), in a process still under investigated. Inflammation can lead to disorganization of extracellular matrix (ECM) and fibrotic alterations, among others. Most of the ongoing research relies on in vivo or ex vivo models that do not truly mimic the human microenvironment. Here, we developed a 3D in vitro model aimed at recapitulating inflammation progression in human AF (hAF) to improve the understanding of AF failure.hAF of herniated samples from low back pain patients were collected and digested as previously established. hAF cells were cultured in 2D and 3D, embedded in collagen-type 1 hydrogels. hAF cells in 2D and 3D were then stimulated with IL-1β (10ng/mL), in acute (48h) and chronic (7days) conditions. After 7 days, cell morphology together with extracellular matrix (ECM) (collagen I and fibronectin) were assessed by immunofluorescence. Inflammatory cytokine secretion were analyzed by a protein array.2D experiments showed alteration of cell morphology, with cell area reduction upon inflammatory stimulation. The profile of inflammatory cytokines secreted showed that: i) IL-1α increases with time in culture, while TNF-α decreases; and ii) IL-1α and MIG/CXCL9 are increased in chronic vs acute inflammation. ECM analysis showed no differences. In 3D culture, AF cell morphologic alterations with inflammation were also observed. Concerning ECM production, collagen I production was reduced with chronic inflammation, while fibronectin remained unaltered. Collagen II and aggrecan appear to increase with chronic inflammation. Cytokine production from 3D culture is currently being assessed. ECM alterations are being complemented by characterization at biomechanical (nanoindentation) level.Our data show that chronic inflammation is crucial to understand AF failure mechanisms and improve the resemblance of human IVD herniation.
MONITORING IN VITRO AND EX VIVO INFLAMMATION USING SINGLE-WALLED CARBON NANOTUBES (SWCNTS) SENSOR TECHNOLOGY
Authors: Belcastro L. , Zubkovs V. , Markocic M. , Sajjadi S.H. , Peez C. , Tognato R. , Boghossian A. A. , Cattaneo S. , Grad S. , Basoli V. 
Published: January 2024

Osteoarthritis (OA) is a degenerative joint disease affecting millions worldwide. Early detection of OA and monitoring its progression is essential for effective treatment and for preventing irreversible damage. Although sensors have emerged as a promising tool for monitoring analytes in patients, their application for monitoring the state of pathology is currently restricted to specific fields (such as diabetes). In this study, we present the development of an optical sensor system for real-time monitoring of inflammation based on the measurement of nitric oxide (NO), a molecule highly produced in tissues during inflammation.Single-walled carbon nanotubes (SWCNT) were functionalized with a single-stranded DNA (ssDNA) wrapping designed using an artificial intelligence approach and tested using S-nitroso-N-acetyl penicillamine (SNAP) as a standard released-NO marker. An optical SWIR reader with LED excitation at 650 nm, 730 nm and detecting emission above 1000 nm was developed to read the fluorescence signal from the SWCNTs. Finally, the SWCNT was embedded in GelMa to prove the feasibility of monitoring the release of NO in bovine chondrocyte and osteochondral inflamed cultures (1–10 ng/ml IL1β) monitored over 48 hours. The stability of the inflammation model and NO release was indirectly validated using the Griess and DAF-FM methods. A microfabricated sensor tag was developed to explore the possibility of using ssDNA-SWCNT in an ex vivo anatomic set-up for surgical feasibility, the limit of detection, and the stability under dynamic flexion.The SWCNT sensor was sensitive to NO in both in silico and in vitro conditions during the inflammatory response from chondrocyte and osteochondral plug cultures. The fluorescence signal decreased in the inflamed group compared to control, indicating increased NO concentration. The micro-tag was suitable and stable in joints showing a readable signal at a depth of up to 6 mm under the skin.The ssDNA-SWCNT technology showed the possibility of monitoring inflammation continuously in an in vitro set-up and good stability inside the joint. However, further studies in vivo are needed to prove the possibility of monitoring disease progression and treatment efficacy in vivo.Acknowledgments: The project was co-financed by Innosuisse (grant nr. 56034.1 IP-LS)
TOWARDS UNDERSTANDING HOW NEUTROPHIL INSTRUCT THE IMMUNE RESPONSE TO BIOMATERIALS
Authors: Bektas E.I. , Wesdorp M. A. , Schwab A. , Stoddart M.J. , Mata A. , Van Osch G.J.V.M. , D'Este M. 
Published: January 2024

Biomaterials with mechanical or biological competence are ubiquitous in musculoskeletal disorders, and understanding the inflammatory response they trigger is key to guide tissue regeneration. While macrophage role has been widely investigated, immune response is regulated by other immune cells, including neutrophils, the most abundant leukocyte in human blood. As first responders to injury, infection or material implantation, neutrophils recruit other immune cells, and therefore influence the onset and resolution of chronic inflammation, and macrophage polarization. This response depends on the physical and chemical properties of the biomaterials, among other factors. In this study we report an in vitro culture model to describe the most important neutrophil functions in relation to tissue repair.We identified neutrophil survival and death, neutrophils extracellular trap formation, release of reactive oxygen species and degranulation with cytokines release as key functions and introduced a corresponding array of assays. These tests were suitable to identify clear differences in the response by neutrophils that were cultured on material of different origin, stiffness and chemical composition. Overall, substrates from biopolymers of natural origin resulted in increased survival, less neutrophil extracellular trap formation, and more reactive oxygen species production than synthetic polymers. Within the range of mechanical properties explored (storage modulus below 5 k Pa), storage modulus of covalently crosslinked hyaluronic acid hydrogels did not significantly alter neutrophils response, whereas polyvinyl alcohol gels of matching mechanical properties displayed a response indicating increased activation.Additionally, we present the effect of material stiffness, charge, coating and culture conditions in the measured neutrophils response. Further studies are needed to correlate the neutrophil response to tissue healing.By deciphering how neutrophils initiate and modulate the immune response to material implantation, we aim at introducing new principles to design immunomodulatory biomaterials for musculoskeletal disorders.AcknowledgmentsThis work was supported by the AO Foundation, AO CMF, grant AOCMF-21-04S.
ANTI-INFLAMMATORY EFFECTS OF PRECONDITIONED BONE MARROW MSC-DERIVED SECRETOME ON DEGENERATED HUMAN NUCLEUS PULPOSUS CELLS IN VITRO
Authors: Tilotta V. , Di Giacomo G. , Cicione C. , Ambrosio L. , Russo F. , Papalia R. , Vadalà G. , Denaro V. 
Published: January 2024

Invertebral disc degeneration (IDD) is a degenerative disease involving a variety of musculoskeletal and spinal disorders such as lower back pain (LBP). Secretome derived from mesenchymal stem cells (MSCs) have exerted beneficial effect on tissue regeneration. In this study, the goal was to investigate the paracrine and the anti-inflammatory effects of secretome from interleukin IL1β preconditioned Bone Marrow MSCs (BMSCs) on human nucleus pulposus cells (hNPCs) in a 3D in vitro model.Secretome was collected from BMSCs (BMSCs-sec) after preconditioning with 10 ng/mL IL1β. hNPCs were isolated from surgical specimens, culture expanded in vitro, encapsulated in alginate beads and treated with: growth medium; IL1β 10 ng/mL; IL1β 10 ng/mL for 24 hours and then BMSCs-sec. We examined: i) cell proliferation and viability (flow cytometry), ii) nitrite production (Griess assay) and ROS quantification (Immunofluorescence) iii) glycosaminoglycan (GAG) amount (DMBB) and iv) gene expression levels of extracellular matrix (ECM) components and inflammatory mediators (qPCR). One-way ANOVA analysis was used to compare the groups under exam and data were expressed as mean ± S.D.In vitro tests showed an enhancement of hNPCs proliferation after treatment with BMSCs-sec (p ≤ 0.05) compared to IL1β group. After 24 hours, the percentage of dead cells was higher in IL1β treated hNPCs compared to control group and decreased significantly in combined IL1β and BMSCs-sec sample group (p ≤ 0.01). Nitrite and ROS production were significantly mitigated and GAGs content was improved by preconditioned BMSCs-sec (p ≤ 0.05). Furthermore, gene expression levels were modulated by BMSCs-sec treatment compared to controls.Our results supported the potential use of BMSCs' secretome as a cell-free strategy for IDD, overcoming the side effects of cell-therapy. Moreover, secretome derived from IL1β preconditioned BMSCs was able to reduce hNPCs death, attenuate ECM degradation and oxidative stress counteracting IDD progression.Acknowledgements: Financial support was received from the “iPSpine” and “RESPINE” Horizon 2020 projects.