AO Foundation

Biomaterials play an increasing role in intervertebral disc regeneration and require preclinical testing, typically performed using organ culture and invitro models. Native human discs are limited, and animal models often fail to mimic human disc degeneration. Thus, enzymes like chondroitinase ABC (chABC) and papain are used to simulate degenerative tissue changes and enable biomaterial injection. In previous work, we characterized the biomechanical and morphological effects of papain, which forms cavities in the disc. In contrast, chABC does not form cavities, but its biomechanical effects remain insufficiently characterized. This study aims to evaluate the macroscopic and biomechanical effects of chABC-specifically, range of motion (ROM), neutral zone (NZ), and disc height-in a bovine organ culture model, and assess the distribution of an injected hydrogel, comparing the results to published papain data. Four groups of fresh bovine tail segments were prepared (n ≥ 10) and three received injections of chABC, papain, or PBS, followed by 7 days of culture. For papain and PBS, published data were supplemented with new specimens. Complex simulated physiological loading was applied to diminish disc swelling. The maximum volume of a serum-albumin-hydrogel was injected into all four groups. ROM, NZ, and disc height were measured before and after enzyme treatment, loading, and injection. Post-injection, microCT scans visualized material distribution within the discs. ChABC increased ROM by up to 92.1%, NZ by up to 79.4%, and decreased disc height by 2.1 mm. Hydrogel injection decreased ROM and NZ but increased disc height in all groups while enzyme treatments allowed more hydrogel injection (0.6 mL for chABC). Exemplary scans showed cloud-like hydrogel spread for chABC and a round-shaped degradation defect for papain. The findings indicate that chABC better simulates disc degeneration, whereas papain better models nucleotomies, and both enzymes preserve annulus integrity-providing valuable models for biomechanical testing.

Modern nutrition science still lacks a comprehensive, machine-readable map linking diet to molecular composition and biological effects. Here we present FoodAtlas, a large-scale knowledge graph that links 1430 foods to 3610 chemicals, 2181 diseases, and 958 flavor descriptors through 96,981 provenance-tracked edges. A transformer-based text-mining pipeline extracted 48,474 quantitative food-chemical associations from 125,723 literature sentences (F1 = 0.67) and integrated them with 23,211 chemical-disease assertions from the Comparative Toxicogenomics Database, 15,222 chemical-bioactivity records from ChEMBL, 3645 flavor annotations from FlavorDB and PubChem, and 6429 taxonomic relationships. Graph embeddings revealed six dietary modules whose signature metabolites delineate distinct, multisystem disease-risk trajectories. Models built on FoodAtlas demonstrate practical utility: a bioactivity predictor achieved strong correlation with antioxidant assays (R² = 0.52; ρ = 0.72), and a substitution engine reduced simulated total disease risk by 11.9%.

Injectable platelet-rich fibrin (i-PRF) is often used in maxillofacial surgery in combination with commercially available materials, but until now no study has compared biological and mechanical interactions between i-PRF and different composition biomaterial scaffolds. This study investigated how biomaterials - Collacone® (Biotiss), Bio-Oss® Collagen (90% Geistlich Bio-Oss®/10% porcine collagen, Geistlich), and CeraForm® (65% hydroxyapatite/35% β-tricalcium phosphate, Teknimed) - interact with i-PRF and influence material degradation, growth factor release, osteoblastogenesis, and osteoclastogenesis. Blood from three healthy donors was centrifuged at 700rpm for 5min to prepare i-PRF. Materials were impregnated with i-PRF and allowed to coagulate for 30min. Surface properties were examined by scanning electron microscopy, and material degradation was monitored for 50days. Growth factor release (IL-6, IL-8, EGF, PDGF, TGF-β1) was quantified by ELISA over 14days. Osteoblastogenesis was evaluated using CellTiter-Blue®, and osteoclastogenesis was assessed through resorption assays on simulated body fluid/collagen type I-coated plates via image analysis and qPCR for differentiation markers. Data was analysed using ANOVA. i-PRF delays the degradation of collagen-containing biomaterials. Impregnation of studied biomaterials with i-PRF only reduced growth factor release during the first 6h. TGF-β1 release increased significantly after platelet activation by foreign surfaces, while collagen-based biomaterials triggered rapid IL-6 and IL-8 release. Composites with i-PRF promoted earlier activation of both osteoclasts and osteoblasts. i-PRF showed different synergetic responses based on collagen and calcium phosphate composition in materials it was combined with. Meaning that these findings provide guidance for optimizing biomaterial and i-PRF combinations in surgical applications and inform the design of next-generation PRF-material composites.

BackgroundKnowledge translation (KT) interventions are essential for implementing evidence-based practices in healthcare. However, despite their proven effectiveness in addressing global health challenges, KT strategies in surgery remain challenging to apply. This scoping review examines KT strategies in surgery, their effectiveness, and key barriers and enablers to their implementation.MethodsThis scoping review followed the Arksey and O’Malley and Levac et al. frameworks, integrating the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) and the PRISM (Practical Robust Implementation Sustainability Model) models to evaluate the effectiveness of knowledge translation interventions in surgical practice change and associated contextual barriers and facilitators. A systematic search was conducted across MEDLINE (PubMed, OVID), CINAHL (EBSCO), and PsycINFO (ProQuest). Articles were screened using predefined selection criteria, emphasizing experimental and quasi-experimental studies. Data extraction categorized KT interventions: knowledge diffusion, dissemination, and implementation approaches.ResultsA total of 34 studies met the inclusion criteria. Most were hospital-based (88%) and focused on guideline adherence. The review identified three primary KT strategies: (i) educational materials and educational outreach, (ii) reminders and prompts, and (iii) audit and feedback systems. The most effective KT strategies used a combination of these interventions to maximize impact. Barriers included physician resistance, limited leadership support, financial constraints, and workflow disruptions, while enablers included institutional leadership, structured training programs, financial incentives, and interdisciplinary collaboration. A notable finding was the lack of standardized validation processes for adopting changes in the surgical setting, which often burdens individual surgeons and their institutions, thereby constraining both capacity and motivation for practice change.ConclusionsFindings suggest that layered, interdisciplinary KT strategies are the most effective for driving surgical practice change and overcoming institutional barriers. The integrated application of RE-AIM and PRISM frameworks proved valuable in assessing the interventions’ sustainability and real-world effectiveness. This comprehensive analysis contributes to the growing body of knowledge on effective implementation strategies in surgical settings and provides a foundation for future practice improvement initiatives. Future research should focus on refining KT methodologies, expanding implementation frameworks, and addressing barriers to sustainability across diverse surgical settings.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12913-025-13369-2.

Primary stability of pedicle screws is critical for successful spinal fixation, particularly in osteoporotic patients, where screw loosening occurs in over 50% of cases. This study combined experimental and numerical approaches to evaluate the primary stability of carbon fibre-reinforced polyether-ether-ketone (CF/PEEK) screws under toggling loading conditions. Fifteen human cadaveric vertebrae with low bone mineral density were tested using a multidirectional loading setup with custom-designed, 3D-printed guides for accurate screw placement. Toggling tests were conducted under displacement-controlled linear loading-unloading ramps with increasing displacements (1, 2, and 4mm). To complement the experiments, a sample-specific, explicit non-linear micro-finite element (μFE) model was developed to simulate the toggling tests. Experimental and numerical peak forces and tangential stiffnesses were compared at different displacement levels. Experimentally, no significant correlation was found between mean bone volume fraction in the vicinity of the screw and peak forces. Similarly, volumetric bone mineral density did not show significant correlation with the experimental biomechanical variables. However, μFE-derived peak forces showed significant correlation with experimental measurements at all displacement levels (R2=0.67, R2=0.60, R2=0.59at 1mm, 2mm and 4mm displacement, respectively), with the model slightly overestimating the experimental values at higher displacements (e.g., 4mm). Across all data points, μFE and experimental peak forces strongly correlated (R2=0.92), following a power-law relationship. This study demonstrates that non-linear μFE models can reliably predict the primary stability of pedicle screws, offering potential for optimizing screw designs and reducing clinical failure rates associated with loosening.

ABSTRACT Immune regulation plays a crucial role during the regeneration process, and it determines the fate of inflammation after tissue injury or infection. Neutrophils serve as the primary immune cells recruited to the site of inflammation, initiating and directing the subsequent inflammatory cascade following implantation. This study investigated the effects of the in vitro standard foetal bovine serum (FBS), either in the culture medium or as a surface coating, as well as type I collagen coating on responses of neutrophils isolated from human peripheral blood using 3D-printed polycaprolactone (PCL) scaffolds. Neutrophil activity was evaluated by assessing metabolic activity and metabolomic profiles, reactive oxygen species (ROS) production, and inflammation-related markers via high throughput proximity extension assay. Type I collagen coating modified the metabolomic profile of neutrophils and MMP-9 release but had minimal effect on ROS generation. In contrast, the presence of FBS in the culture medium significantly influenced neutrophil behavior, leading to significant changes in metabolic activity, cytotoxicity, and the secretion of inflammation-associated molecules, even at concentrations as low as 1% (v/v). These findings highlight the importance of assessing the use of FBS in neutrophil culture models, particularly those isolated from humans, and emphasize the development of alternative platforms for investigating neutrophil–cell interactions in a more physiologically relevant manner. Highlights Neutrophil response to FBS(1–10%) and collagen coatings on PCL scaffolds was tested. FBS impacts neutrophil activation and alters metabolite composition of the medium. FBS increased the release of inflammation-related molecules such as NE, IL-8 and VEGFA. Collagen changed neutrophil metabolites and decreased MMP-9 release. Results addressed the FBS bias and the need for physiologically relevant culture models. Abstract Figure