Acta Biomaterialia

The foreign body response (FBR) is an immune mediated event that occurs with every material implant. The extent of the fibrosis is dependent on many factors including the biomaterial design, tissue location, and host factors such as age, sex, ancestry, diet. There are known clinical outcomes of implants dependent on age and sex, including increased fibrosis and implant failure in aged and female patients. As the population ages, there is a growing need to understand how aging affects the FBR, and how preclinical models can capture this to guide biomaterial design. Here, we investigated how chronic fibrosis in a murine model of the FBR is altered by two biological factors: age and sex. We investigated changes in fibrosis using a volumetric muscle loss (VML) injury model coupled with polycaprolactone (PCL) or polyethylene (PE) microparticle implants. Fibrosis was quantified through gene expression, microscopic analysis of histologic sections, and the corresponding immune response measured via gene expression and flow cytometry data. We found gene expression differences with immune pathways enriched in female mice, and microscopy revealed collagen birefringence area increased in young male mice. Both the innate and adaptive immune response were altered by age and sex via T cell and macrophage phenotype, and the effects of aging differed between sexes. These results reveal both variables contribute to discrepant outcomes in both fibrosis and the local immune response to synthetic material implants. This demonstrates a clear need to understand and account for the influence of biological factors in biomaterial design.

Purpose: Fibrotic remodeling of the uterus, associated with aging, disease, and environmental exposures, alters collagen organization and tissue stiffness, yet how these changes influence organ-level mechanical behavior remains poorly understood. Glutaraldehyde (GA)-induced collagen crosslinking was used as a controlled surrogate for fibrotic remodeling to determine whether image-informed inverse finite element analysis (iFEA), combined with inflation testing and micro-computed tomography (microCT), could detect and quantify the resulting changes in uterine constitutive behavior. Methods: Murine uteri (n = 6 untreated, n = 6 GA-crosslinked) underwent volume-controlled balloon inflation with simultaneous microCT imaging to quantify deformation of the inner and outer wall boundaries for iFEA. Specimen-specific Gasser-Ogden-Holzapfel (GOH) finite element models were optimized by adjusting model parameters to reproduce experimentally measured wall contours throughout inflation. Model performance was evaluated using contour root mean square error (RMSE), and parameter identifiability was assessed through sensitivity analyses. Results: GA treatment significantly increased inflation work, linear stiffness, and maximum inflation resistance (p < 0.001). The iFEA framework accurately reproduced experimental deformation (RMSE < 3%) and revealed significant increases in the estimated GOH parameters C10 (9.2-fold), k1 (2.0-fold), and k2 (2.7-fold), consistent with increased effective tissue stiffness and a shift toward earlier collagen fiber recruitment. Sensitivity analyses demonstrated unique, well-defined minima for all parameter combinations. Conclusion: Image-informed iFEA provides a quantitative framework for relating collagen remodeling to organ-level uterine mechanics through specimen-specific constitutive parameter estimation. This approach establishes a foundation for investigating the mechanical consequences of uterine fibrosis and other remodeling processes.

Osteochondral repair requires restoration of zonally organised articular cartilage and subchondral bone, yet translatable implants rarely reproduce this spatial complexity. Here, we developed an off-the-shelf, cell-free multilayer scaffold comprising a superficial 2% (w/v) articular cartilage extracellular matrix (AC-ECM) phase, an intermediate 5% AC-ECM phase and a basal 6% bone ECM (BN-ECM) phase. The scaffold formed continuous interfaces, displayed regionally distinct pore sizes and resisted permanent deformation during cyclic compression. In vitro, constructs seeded with caprine mesenchymal stromal and articular cartilage progenitor cells supported cell expansion and the accumulation of sulfated glycosaminoglycan- and collagen-rich matrix, with regional differences in collagen I, II and X deposition. Following eight weeks of subcutaneous implantation, cell-seeded scaffolds contained more collagenous matrix than unseeded controls, while vascularisation preferentially localised to the BN-ECM phase. The scaffold was then evaluated against empty defects in a caprine osteochondral model for six months. Scaffold treatment significantly improved macroscopic and histological repair, increased chondral tissue fill (~60% versus ~40%), limited cartilage-like tissue extension into the subchondral region and generated a more native-like superficial collagen organisation. Repair tissue further exhibited greater collagen II immunoreactivity, increased ACAN and COL2A1 expression and reduced COL1A2 expression relative to empty defects, although deeper bone repair was not significantly improved. These findings demonstrate that tissue-specific ECM layering can spatially guide endogenous repair and substantially improve cartilage restoration without exogenous cells or growth factors in a clinically relevant large-animal model, while identifying subchondral bone regeneration as the remaining design challenge for complete osteochondral repair.

Tympanic membrane perforations remain a common clinical problem, and although surgical intervention through tympanoplasty achieves high success rates, it is associated with donor-site morbidity, surgical complexity and limited restoration of the native radial and circumferential collagen architecture. In this study, 3D extrusion printing was utilized to create an active scaffold and attempt to promote collagen organization through shear-mediated structural alignment. An alginate-carboxymethyl cellulose (CMC) hydrogel with bovine SIS-dECM was prepared and investigated for its suitability as a bioink alternative to tympanoplasty grafts. The physiochemical, rheological and printability characteristics of the hydrogel were assessed. Successful decellularization was confirmed by histological analysis. The incorporation of the SIS-dECM into the hydrogel led to increased swelling, lower apparent viscosity, yield stress and flow stress while maintaining favourable printability and filament stability. Polarized optical microscopy was also used to study the influence of printing speed on the alignment of collagen to mimic the native tympanic membrane radial collagen architecture. Compared with the cast controls, the printed samples presented stronger birefringence signals. Biological evaluation demonstrated that the 15% dECM hydrogel exhibited the highest live cell area percentage and live/dead ratio after 48 h. In addition, the chick chorioallantoic membrane assay demonstrated that the dECM-containing hydrogels improved vascular density. The findings establish a printable, biologically active dECM bioink capable of generating bulk collagen organization through extrusion printing as a platform for tympanic membrane regeneration.

During tumor growth and progression, cancer cells are exposed to sustained physical confinement and volumetric compression that can alter cell volume, cytoskeletal organization, mechanotransduction, and invasive behavior. However, whether breast cancer cells retain a compression-induced mechanical memory after release from sustained volumetric compression, and how this memory influences subsequent migration and invasion, remains poorly understood. Here, by controlling cell volume using PEG - mediated volumetric compression, we investigated the compression and post-compression recovery responses of MCF-7 breast cancer cells. Cells were compressed for four days, followed by four days of recovery after PEG removal, and analyzed using daily morphological tracking, single-cell time-lapse imaging, F-actin and YAP staining, wound healing assays, and 3D spheroid invasion assays. We show that sustained volumetric compression shifts MCF-7 cells into a compact, jammed-like, low-motility state characterized by reduced morphodynamic remodeling, suppressed collective migration, and limited spheroid invasion. In contrast, post-compression recovery induces a distinct mechanobiological state marked by increased cell area and perimeter, altered single-cell trajectories, heterogeneous F-actin remodeling, enhanced YAP nuclear localization in enlarged recovered cells, accelerated wound closure, and increased spheroid invasion and cell dissemination. These findings suggest that prior volumetric compression can prime breast cancer cells for enhanced migration and invasion after stress release, supporting post-compression recovery as a form of mechanical memory that may contribute to tumor dissemination.

Collagen, a major component of the extracellular matrix, regulates cellular behaviors, such as adhesion, differentiation, and angiogenesis. These functions are mediated by interactions between specific amino acid motifs within the collagen triple-helical structure and collagen-binding biomolecules. These include cell-surface receptors, such as integrins, discoidin domain receptors (DDRs), and syndecans, a family of transmembrane heparan sulfate proteoglycans (HSPGs). Signals mediated by these receptors are integrated to regulate cell fate. However, native collagen simultaneously presents multiple receptor-binding motifs, making it difficult to isolate receptor-specific functions and to evaluate receptor crosstalk. Here, we introduce a composition-controlled artificial collagen matrix platform that enables independent tuning of multiple receptor-binding motifs within a constant triple-helical scaffold. This material was produced by disulfide crosslinking of chemically synthesized collagen-like triple-helical peptides, each bearing a single defined receptor-binding sequence. By varying the mixing ratios of these peptides before crosslinking, we systematically controlled the composition of receptor-binding motifs within the matrices. We applied this platform to nerve growth factor-dependent neuronal differentiation of PC12 cells, a process supported by collagen. Matrices containing only integrin-binding sequences were sufficient to support this differentiation. Incorporation of an HSPG-binding sequence had little additional effect, whereas incorporation of a DDR-binding sequence suppressed integrin-mediated differentiation and coincided with DDR phosphorylation. These results reveal opposing roles of collagen-binding integrins and DDRs in regulating PC12 cell differentiation. Composition-controlled artificial collagen provides a versatile matrix platform for dissecting functional crosstalk among collagen receptors.

Tessellated calcified cartilage (TCC) is a hallmark of the chondrichthyan skeleton, yet its development early in ontogeny across the four major groups (batoids, galeomorphs, squalomorphs, and holocephalans) remains poorly understood. Specialised traits of TCC, such as multi-layered TCC and internal mineralised trabeculae, typically develop in response to feeding mechanics. In this study, we evaluated TCC morphology in the jaws of 12 representative taxa to observe its structure at an early ontogenetic stage to determine whether these specialised features had yet developed. Batoids consistently exhibited well-developed, homogeneous, polygonal tesserae early in ontogeny regardless of jaw morphology or feeding habit. In contrast, galeomorphs displayed high morphological heterogeneity. Notably, we document the first report of an extensive internal trabecular network in a non-batoid elasmobranch, observed in Ginglymostoma cirratum, which may serve to resist the mechanical pressures of specialised suction feeding. Furthermore, we identified voussoir tesserae in galeomorphs for the first time, extending their documented presence across all elasmobranch groups, where they display an inverted aspect ratio (wider than tall) compared to mature forms. The durophagous Mustelus mustelus exhibited surprisingly poor TCC development despite being a durophagous feeder, pointing to a pronounced ontogenetic lag. In Squatina oculata, TCC was characterised by large and thick tesserae and extensive fused tesseral regions which may relate to its explosive ambush predation mode, whereas the holocephalan Chimaera exhibited a poorly mineralized, mesh-like structure without resolvable discrete tesserae or trabeculae-matching findings from previous studies. Across all specimens, multi-layered TCC was absent, confirming that multi-layering develops later in ontogeny. These results demonstrate that generalised models of TCC development based on one group or a few taxa fail to capture the broader diversity of TCC morphology. It also opens up many exciting avenues for further study, and forms the basis for comparisons with fossil chondrichthyans, to investigate the evolution of TCC.

Neurodegenerative diseases are increasingly associated with vascular dysfunction beyond progressive neuronal degeneration, yet how vascular pathology contributes to disease progression remains poorly understood, largely due to the lack of a neurodegenerative disease model capable of capturing neuronal pathology alongside associated vascular dysfunction. Here, we developed a microengineered 3D vascularized brain tissue model that integrates neurospheroids with a self-assembled, perfusable vascular network to recapitulate key features of the neurovascular interface. Using this model, we investigated the vascular contribution to Parkinson's disease pathology by introducing -synuclein preformed fibrils into the engineered vasculature. Intravascular -syn fibril exposure induced endothelial barrier disruption, vascular leakage, inflammation, and vascular regression. Notably, this vascular insult was accompanied by intraneuronal -synuclein aggregation within neurospheroids, suggesting that vascular dysfunction may facilitate the exposure of neural tissue to pathogenic -synuclein. Our neurodegenerative disease modeling approach establishes a versatile and tractable platform for investigating vascular contributions to neurodegenerative disease progression.

Successful cartilage repair remains one of the most significant challenges in the musculoskeletal field. Microfracture (MFx), a form of marrow stimulation, remains the predominant repair technique, but it exhibits routine failure due to inadequate defect fill and inferior fibrotic tissue formation. Whereas current strategies focus on augmenting MFx with scaffolds and bioactive factors, the potential to target the MFx clot itself and use the capabilities of this dynamic environment to guide MFx repair remains largely unexplored. We verified that MFx contraction and fibrosis hinder repair success in minipigs and become evident as early as one week in multiple animal models. Therefore, our objective was to investigate and direct microenvironmental interactions in the MFx clot to promote volumetric maintenance and reprogram cells from a fibrotic to more chondrogenic phenotype. Extracellular control of cell-environment interactions, through fibrinogen augmentation or anti-fibrinolytic treatment, limited contraction but had no effect on or even exacerbated the fibrotic susceptibility of marrow-derived cells (MDCs). Intracellular control of microenvironmental interactions, through modulation of the Rho-ROCK pathway, drove TGF-{beta}3 activity of MDCs along a "chondro-fibro axis". In particular, treatment with the ROCK inhibitor Fasudil drove TGF-{beta}3-treated cells away from a myofibroblast phenotype and towards chondrogenesis. Short-term Fasudil treatment prevented TGF-{beta}3-driven macroscale clot contraction and enhanced cartilage-specific matrix deposition in vitro. In a pilot rat study, this combination treatment improved GAG deposition and better protected surrounding cartilage. These findings suggest that Rho-ROCK modulates TGF-{beta} signaling along this chondro-fibro axis and its precise control could be the key to promoting precise and volumetric cartilage repair through microenvironmental interactions.

Disruption of the wound healing cascade can result in pathological outcomes, including fibrosis due to myofibroblast-mediated contraction and collagen deposition. Despite the clinical significance, effective treatments for fibrosis remain limited as current therapies often show inconsistent efficacy, adverse effects, and patient discomfort. Combinatorial therapeutic strategies integrating biomaterial scaffolds with gene delivery have shown promise in regenerative healing. MicroRNAs (miRNAs) are key regulators of fibrotic signalling in cells, including fibroblasts and myofibroblasts. Specifically, miRNA-29b is notable for downregulating pro-fibrotic genes, including collagen type I, reducing ECM accumulation, and limiting fibroblast/myofibroblast overactivation. In this context, the present work develops a collagen-GAG (CG) scaffold platform for delivery of miRNA-29b complexed GET nanoparticles to inhibit fibrosis. Initially, bioinformatic analysis of miRNA-29b validated its involvement in ECM-associated pathways and processes, followed by successful nanoparticle internationalisation in primary dermal fibroblasts. The anti-fibrotic efficacy of the optimised miRNA-29b nanoparticles was subsequently demonstrated by significant reductions in collagen deposition and -SMA expression, both key indicators of myofibroblast differentiation and fibrosis. The optimised miRNA-29b formulation was then incorporated into 3D porous collagen-GAG (CG) scaffolds, which modulated fibrotic gene expression while preserving scaffold structure conducive to fibroblast/myofibroblast infiltration and proliferation. Finally, functional outcomes of seeded TGF-{beta}-stimulated fibroblasts, including reduced matrix contraction, -SMA expression, and ECM deposition, were comparable to those observed in non-fibrotic conditions, thereby confirming the therapeutic potential of scaffold-mediated miRNA-29b delivery. Together, these findings demonstrate that scaffold-mediated miRNA-29b delivery represents a promising anti-fibrotic strategy for wound healing by mitigating myofibroblast activation, limiting matrix contraction, and preventing pathological ECM accumulation.

Embedded extrusion printing can process collagen-rich bioinks, but their low viscosity and slow fibrillogenesis compromise print fidelity and post-deposition stability. Here, we developed a collagen fibril-inducing support bath (FIB) that combines mechanical support for embedded printing with biochemical induction of collagen assembly. Microfibrillated or nanofibrillated cellulose was incorporated into a fibril-inducing buffer, and formulations were screened at 37 degrees Celsius for rheological behaviour and optical transparency. The selected FIB was evaluated by printing 1% and 5% (w/v) articular cartilage-derived extracellular matrix (ECM) inks at 10-20 mm/s and compared with a cellulose-only control bath. FIB exhibited yield-stress, shear-thinning and rapid recovery behaviour that supported reproducible filament deposition. Unlike the control bath, FIB enabled intact construct retrieval following stabilisation and promoted the formation of fibrillar collagen within the printed strands. Scanning electron microscopy revealed D-banded collagen fibrils preferentially oriented along the deposition direction, with dominant orientation peaks within +/- 10-15 degrees. The platform supported the fabrication of 15 x 15 x 1.5 mm sheets and 6 x 6 x 6 mm scaffolds whose macroscopic dimensions were retained after processing. Constructs produced from 5% ECM inks exhibited approximately fourfold higher ramp and relaxation moduli than those produced from 1% ECM inks. Extracts from both formulations caused no detectable reduction in cell metabolic activity after 24 h or 72 h. Mesenchymal stem/stromal cells (MSCs) seeded onto printed sheets became markedly elongated and aligned by day 3, with approximately 80% of cells having an aspect ratio exceeding 1.5, significantly greater than cells seeded onto casted ECM controls, with a mean deviation of ~9 degrees from the filament print direction. These findings establish FIB as a bioactive support bath that couples embedded printability with collagen fibrillogenesis, enabling recoverable collagen-rich constructs with aligned fibrillar architecture that directs early cellular organisation.

Low-density lipoprotein (LDL) is a major atherogenic lipoprotein, yet its potential to directly modify the fibrin scaffold of blood clots is incompletely understood. Here, we investigated how LDL alters plasma fibrin network architecture and internal fibrinolysis across defined fibrinogen/thrombin conditions. Pooled normal human plasma was supplemented with LDL and clotted with controlled concentrations of fibrinogen and thrombin. Fibrin architecture was visualized by confocal microscopy and quantified by pore-size analysis; clot formation and lysis were monitored turbidimetrically in the presence of tissue plasminogen activator (tPA). Increasing LDL produced a pronounced reduction in fibrin-network pore size across the tested fibrinogen/thrombin conditions. The LDL dependence of pore diameter was well described by a power-law relationship, D_pore=(6.54 +/- 0.11)[LDL]^(-0.12 +/- 0.02) , (R^2 = 0.90), with a significant negative LDL exponent (p = 4 x 10^5). Increasing LDL also prolonged clot lysis time and altered turbidity kinetics. These findings extend epidemiologic and clinical associations between ApoB-containing lipoproteins and hypofibrinolytic clot phenotypes by demonstrating, in a controlled plasma system, that LDL itself can modify fibrin network architecture and fibrinolytic susceptibility. The results support a structure-function role for LDL within the fibrin biomaterial and motivate direct tests of LDL incorporation, protofibril packing, fibrinolytic-protein binding, and single-fiber mechanics.

Cell therapies involving human adipose-derived stromal cells (hASCs) have shown promise for a range of clinical applications due to their ability to stimulate angiogenesis and dampen inflammation via paracrine mechanisms. However, a major barrier to the successful clinical translation of hASC-based therapies is that standard culture methods for expansion on rigid 2D tissue-culture polystyrene under static conditions diminish the pro-regenerative functionality of the cells. To address these limitations, the current project focused on the development of an in vitro bioreactor system for preconditioning hASCs to augment their capacity to stimulate regeneration through paracrine mechanisms. Specifically, the combined effects of decellularized adipose tissue (DAT) coatings, shear-stress stimulation, and varying oxygen tensions on hASC expansion and paracrine factor secretion were assessed. Additional studies were performed to characterize the effects of stimulating hASCs within the rocking bioreactor system using the pro-inflammatory cytokines IFN-{gamma} and TNF-. Expansion in the bioreactor under all conditions supported hASC growth with no observable morphological differences. However, dynamic culture on DAT coatings enhanced intracellular indoleamine 2,3-dioxygenase (IDO) expression in hASCs cultured under 20% O2. Moreover, culturing under dynamic conditions and/or on DAT coatings significantly increased secretion of the pro-angiogenic factors VEGF, HGF, and angiogenin. When pro-inflammatory cytokine priming was introduced, the expression of all tested paracrine factors was enhanced, particularly the immunomodulatory factors IL-6, IL-8 and MCP-1. Overall, a novel bioreactor system was developed for hASC expansion and preconditioning, demonstrating that the cell microenvironment can be tuned to modulate hASC paracrine factor secretion.

Amyloid fibrils are highly ordered protein aggregates characterized by a conserved cross-{beta}-sheet architecture despite originating from structurally diverse precursor proteins. Growing evidence suggests that interactions between different amyloidogenic proteins can modulate aggregation pathways through heterologous cross-seeding; however, the influence of seed polymorphism on the structure and biological properties of cross-seeded fibrils remains poorly understood. Here, we investigated the cross-seeding of native human insulin by two structurally distinct polymorphs of hen egg-white lysozyme (HEWL): flexible fibrils (FFs) and rigid fibrils (RFs). Native insulin remained stable under physiological conditions and underwent spontaneous fibrillation only under acidic conditions. In contrast, both HEWL polymorphs efficiently induced insulin aggregation at physiological pH, bypassing the nucleation barrier. Thioflavin T fluorescence, circular dichroism spectroscopy, and transmission electron microscopy revealed that lysozyme FFs templated the formation of insulin flexible fibrils (IFFs), whereas lysozyme RFs produced insulin rigid fibrils (IRFs), demonstrating that the structural characteristics of the parental HEWL polymorphs were propagated during heterologous cross-seeding. The toxicity of the resulting insulin fibrils was evaluated in SH-SY5Y neuronal cells and CCF-STTG1 astrocytes. IFFs exhibited minimal cytotoxicity and only subtle morphological alterations, whereas IRFs caused modest reductions in cell viability accompanied by more pronounced cellular damage. These findings demonstrate that the structural polymorphism of HEWL fibrils governs both the architecture and biological activity of cross-seeded insulin fibrils, highlighting amyloid polymorphism as an important determinant of heterologous amyloid propagation and a potential design principle for engineering functional amyloid-based biomaterials and protein delivery platforms.

Sensory and motor neurons differ significantly in their morphology, structural organization, functional properties, and mode of action. However, despite this heterogeneity, many in vitro studies focus only on a single neuronal subtype, mainly being sensory neurons, limiting the translational potential and relevance of these studies for the evaluation of therapeutic options for spinal cord injury. In this study, we investigate the differentiation, maturation, and neuronal outgrowth of human induced pluripotent stem cell (iPSC)-derived motor and sensory neurospheres using polyethylene glycol (PEG)-microgels with various bioactive coatings. Our results show subtype-specific responses to the PEG-microgel scaffolds, with respect to motor and sensory neurosphere morphology and size. Furthermore, we compare the formation of the PEG-microgel/scaffolds when starting from iPSCs-derived precursor neuron spheres versus undifferentiated iPSCs. We observe notable differences in structural organization, maturity, and neuronal outgrowth between the two approaches, as well as between motor and sensory neurospheres. Together, these results underline the importance of studying motor and sensory neurons separately and highlight the need for a controlled, tunable culture platform to assess the impact of the microenvironment and to improve the physiological relevance of in vitro platforms for neuron-based research.

Decellularized extracellular matrix (dECM) scaffolds are increasingly used in regenerative medicine, yet the extent to which processed placental dECM retains properties capable of influencing cellular responses remains unclear. This study combines functional cell assays with deep learning-enabled quantitative imaging to determine how dehydrated placental ECM regulates cellular behavior across multiple human cell lineages. Human dermal fibroblasts, cardiac fibroblasts, and osteoblasts were cultured on dehydrated placental ECM or standard cell culture surfaces and assessed for cell attachment, viability, extracellular matrix production, and nuclear morphology. Placental dECM supported attachment and survival across all three cell types, while Pro-Collagen I Alpha 1 secretion varied by cell lineage relative to negative controls. To identify structural responses associated with scaffold culture, an automated imaging pipeline combining Cellpose-based nuclear segmentation with nuclear morphometric analysis was used to quantify nuclear area, eccentricity, and circularity. Quantitative profiling of hundreds of nuclei revealed scaffold-dependent remodeling of nuclear morphology that was not apparent by conventional microscopy. Cells cultured on placental dECM exhibited reduced nuclear area and increased nuclear eccentricity, while cardiac fibroblasts and osteoblasts showed alterations in nuclear circularity. These lineage-dependent morphological responses demonstrate that placental dECM provides more than a permissive substrate for cell attachment and is associated with measurable changes in cellular architecture following processing. Together, these findings support the biological relevance of processed placental dECM as a regenerative biomaterial and demonstrate the utility of quantitative single-cell morphometric analysis for detecting cell-material interactions that may not be apparent through qualitative imaging alone, guiding the rational design of regenerative therapies.

Musculoskeletal symptoms are frequently reported following silicone breast implantation. However, the biological mechanisms linking implant-derived silicone exposure to skeletal muscle alterations remain poorly understood, partly because the biological effects of silicone have long been debated in the context of its biocompatibility. Here, we chemically characterized the low-molecular-weight fraction of the breast implant silicone exposome, readily released from implant gel through gel bleed, and investigated its potential biological consequences using an integrated approach combining analytical chemistry, clinical transcriptomics and histology, and controlled in vitro muscle experiments. Transcriptomic analyses of periprosthetic tissues associated with silicone implant rupture revealed unexpected myogenic and neuromuscular signatures in tissue conventionally regarded as predominantly fibrous, together with alterations in lipid metabolism and transport. These findings were supported by histological evidence of close interactions between periprosthetic tissue and skeletal muscle. Chemical analysis of the implant-gel extract detected linear siloxane L2 and cyclic siloxanes D3-D8, with tentative assignment of D9. In vitro, C2C12 cells exposed to the implant-gel extract showed up to 30% reduced viability and decreased expression of key neuromyogenic genes. Together, these findings provide convergent chemical, clinical, and experimental evidence that low-molecular-weight constituents of the breast implant silicone exposome may constitute a biologically active exposure capable of affecting skeletal muscle. The associated alterations in lipid metabolism and transport further provide a mechanistic framework for investigating the cellular handling and potential tissue distribution of hydrophobic silicone-derived species. These findings position silicone gel bleed as a biologically relevant source of chemical exposure rather than solely a material-integrity phenomenon.

Living myocardial slices (LMS) are a highly relevant ex vivo model for investigating cardiac physiology and disease, as they preserve the native three-dimensional architecture, cellular diversity, and extracellular matrix of the heart. In addition, LMS enable longitudinal functional and molecular analyses. In this study, we established and compared two LMS culture approaches: an air-liquid interface system and a biomimetic culture system. We further examined how different slicing techniques affect tissue quality and longevity within the biomimetic setup. To develop a fibrosis model, LMS were stimulated with transforming growth factor-beta1 (TGF-beta1) and/or exposed to increased mechanical load. Tissue viability was assessed using LIVE/DEAD staining and the MTT assay, while cytotoxicity was evaluated with the LDH-Glo-TM Cytotoxicity assay. Contractile function was measured, and fibrotic remodelling was analysed using RT-qPCR, ELISA, and immunohistochemistry. Our results demonstrate that LMS cultured in the biomimetic system exhibit superior viability, structural integrity, and functional performance compared with those maintained at the air-liquid interface. Mouse LMS could be stably cultured for up to one week in the biomimetic system. Importantly, sample preparation, particularly the slicing method, had a significant impact on tissue quality and culture duration. While TGF-beta1 stimulation alone did not consistently induce fibrosis, combining TGF-beta1 treatment with increased mechanical load led to more pronounced fibrotic remodelling in LMS. These findings highlight the importance of biomechanical cues in modelling cardiac fibrosis ex vivo and support the biomimetic system as a robust platform for functional and disease-relevant studies.

Cerebral aneurysms are abnormal outpouchings of arteries within the brain and occur in [~]1 in 30 adults. Their initiation, growth, and rupture have been linked to focal blood flow abnormalities--often termed "disturbed" or "hostile" hemodynamics--but commonly-used hemodynamic metrics yield conflicting associations with pathology and lack a unifying mechanistic interpretation. Building on a theoretically-grounded link between wall shear stress and near-wall vorticity, we hypothesized that a topology-based description of near-wall flow can operationalize the concept of hostile hemodynamics in a reproducible way. Inspired by atmospheric tornadic phenomena, we sought a principled taxonomy of coherent near-wall fluid structures with potential mechanobiological and clinical implications. Using high-fidelity computational fluid dynamics simulations in anatomically realistic geometries, we identified coherent near-wall fluid structures whose organization mirrors well-studied atmospheric phenomena: tornado-like columnar rotating cores; downburst-like nonrotating wall-impinging jets with tangential outflow, roll-cloud-like tangential vortices; and mixed configurations. These tornadic events on the aneurysm luminal surface were identified from wall shear stress topology, consistent with its theoretical connection to near-wall vorticity kinematics. The presence of tornadic phenomena--and their imprints on the aneurysm wall--was independently observed in vivo using 4D flow magnetic resonance imaging. By translating concepts from atmospheric physics into vascular biomechanics, this topology-based framework yields a unified mechanistic language for describing near-wall hemodynamics, resolving blood flow complexity into interpretable and reproducible coherent fluid structures, enabling standardized hemodynamic phenotyping, and supporting hypothesis-driven studies of aneurysms and other cardiovascular diseases where greater fluid-mechanical specificity and interpretability may strengthen links between mechanobiology and clinical risk.

Rhizomorphs are specialised, root-like fungal structures whose hierarchical organisation may offer a route to reinforcing mycelium-based materials, yet the environmental regulation of their network formation remains poorly understood. Here, we develop an image-based framework to characterise the longitudinal growth and organisation of Armillaria gallica rhizomorphs under varying nutrient availability and light exposure. Time-lapse imaging was combined with image segmentation, skeleton-based network analysis, optical measurements and Gompertz growth modelling. Nutrient availability produced a distinctly non-monotonic response. Moderate nutrient limitation (0.5 x standard concentration) favoured rapid and coherent exploratory growth, whereas intermediate enrichment (1.5 x) produced the greatest eventual network extent, reaching approximately 975 mm total strand length; network extent and radial expansion differed significantly across nutrient levels (padj = 0.0012). Further enrichment maintained substantial fungal coverage without additional network elaboration, consistent with a shift from long-range exploration towards more locally consolidating growth. By contrast, exclusion of ambient light produced no significant differences after multiple-testing correction. These results reveal a resource-dependent trade-off between exploration and network elaboration, demonstrate that fungal coverage and organised network formation are distinct outcomes, and provide a quantitative basis for controlling self-organised biological architectures for bio-derived material design.