Interface Focus

This study demonstrates the feasibility of using a Teflon-AF-based tube-in-tube saturator for fast and precise adjustment of oxygen concentrations in liquids, extending its relevance to human cell culture applications beyond organ-on-chip systems. The system achieves high, near-saturation oxygen concentrations of the liquid phase, with performance influenced by various parameters such as temperature, volume flow rate, and tube length. We demonstrate that the tube-in-tube saturator exhibits high sensitivity to variations in these parameters at low oxygen concentrations, whereas this sensitivity diminishes as saturation is approached. To elucidate the underlying mass transfer processes, kinetic experiments were combined with computational fluid dynamics simulations. The simulation results are in good agreement with the experimental data, and the developed model enables a reliable prediction of oxygen concentrations in the liquid phase under varying operating conditions. Owing to its design, performance, versatility, and portability, this system introduces a new approach for the precise and rapid control of oxygen concentrations in liquids for microscale and macroscale human cell culture applications, offering seamless integration with natural vascular or artificial perfusion networks.

Maternal thermal strain is associated with adverse pregnancy outcomes, yet fetal temperatures cannot currently be directly measured, limiting quantification of fetal thermal strain. Here, we develop two steady-state models for estimating internal temperatures in a near-term fetus. First, we improve the only previously published human fetal thermoregulation model, deriving a closed-form solution within its simplified uniform-cylinder representation. Second, we introduce a multilayer, anatomically segmented model that resolves tissue-specific temperatures. Both couple the fetal body to central blood pool and amniotic fluid compartments and incorporate a new placenta-umbilical cord heat-exchanger representation. Predictions agree with available intrauterine scalp measurements, with fetal core and head-center temperatures approximately 0.5{degrees}C and 0.8{degrees}C above maternal core, respectively. Physiologically plausible changes in umbilical cord heat-exchanger effectiveness or blood flow increased fetal temperatures by approximately 0.3{degrees}C. These models enable estimation of otherwise inaccessible temperatures, while the multilayer formulation lays a foundation for transient, coupled maternal-fetal thermoregulation modeling.

Background Tumor hypoxia and abnormal vasculature are closely associated with aggressiveness in solid tumors. Therefore, noninvasive assessment of these features in primary breast cancer is needed. Photoacoustic (PA) imaging is an emerging modality that enables real-time visualization of vascular architecture and hemoglobin oxygenation. Methods Breast PA imaging was performed in patients with primary breast cancer using a bed-type PA imaging system equipped with a hemispherical sensor and a flat specimen holder enabling mild breast compression. Three independent evaluators assessed predefined characteristics of tumor-associated vasculature: centripetal/disrupted vessels and intratumoral vessel-like signals. Oxygenation (S-factor) of tumor-associated vessels was estimated using dual-wavelength laser irradiation at 756 and 797 nm. Results PA imaging was performed in 9 tumors from 8 patients. Eight tumors were evaluable, after the exclusion of 1 tumor with segmental bloody discharge. Centripetal/disrupted vessels were identified in 7 tumors (87.5%). Intratumoral vessel-like signals were observed in all tumors (100%), with higher signal density than in surrounding tissue in 5 lesions (62.5%). Increased intratumoral signal density was associated with a higher Ki67-labeling index (two-sided P = .01). Mean intratumoral S-factor level (76.9% {+/-} 9.1%) was significantly lower than that of peritumoral vessels at 5 mm (86.4% {+/-} 5.9%) and 20 mm (88.5% {+/-} 4.9%) from the tumor margin (two-sided P < .01). Conclusion PA imaging with a flat specimen holder enables noninvasive visualization of tumor-associated vasculature with reduced oxygenation in primary breast cancer. This approach may provide a novel imaging platform for the early detection and functional assessment of breast cancer.

In the United States, roughly 550,000 people receive routine hemodialysis for end-stage renal disease. This treatment requires an arteriovenous access, most commonly a brachiocephalic fistula. However, these accesses often fail due to stenosis in the cephalic arch (CA), a common complication whose underlying causes remain unclear (Bennet et al., 2015). To characterize the hemodynamic environment in the CA, we employed patient-specific millifluidic models that were perfused with blood-mimicking fluid containing fluorescently labelled beads to visualize flow behaviors. We perfused our models across physiologic (28-45 mL/min) and elevated (60-423 mL/min) flow rates and quantified wall shear stress (WSS) and streamline angle as a measure of flow disturbance. Our findings show that the bulk curvature and remodeled wall topography each create regions of persistently low WSS, consistent with prior clinical observations (Hammes et al., 2016). Moreover, remodeled wall topography promotes disturbed flow at elevated flow rates, a hemodynamic profile associated with various vascular pathologies (Chiu & Chien, 2011). Independently performed computational fluid dynamics (CFD) modeling complements these results, showing that remodeled wall topography promotes vortex formation at elevated flow rates, as assessed by Q-criterion. Collectively, our experimental and computational results provide strong evidence for geometry-driven disturbed flow in the CA at elevated flow rates. Notably, we observed disturbed flow at flow rates as low as 81 mL/min, far below the 600 mL/min required for hemodialysis. Disturbed flow thus offers a plausible mechanism that relates access flow rates to the vascular pathologies that precede access failure. Significance StatementHemodialysis requires an arteriovenous fistula (AVF) that must remodel and mature to withstand chronically elevated blood flow rates. However, how remodeled vessel geometry interplays with elevated flow to shape local hemodynamics remains poorly understood. Here, we used millifluidic models of the cephalic arch (CA) to show that vessel geometry and elevated flow rates promote regions of low wall shear stress and disturbed flow. Notably, geometry-driven disturbed flow is observed at flow rates above physiologic levels but well below 600 mL/min, the flow rate necessary for adequate dialysis. Because disturbed flow is injurious to the endothelium, our findings are the first to show that vascular damage begins before fistula maturation.

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.

IntroductionPreeclampsia is characterized by a pro-inflammatory, anti-migratory and anti-angiogenic placental phenotype. Impaired spiral artery remodeling stemming from trophoblast dysfunction is a key pathogenic mechanism. Little is known about the processes that govern trophoblast function normally and in preeclampsia. In preeclampsia, placental Let-7b-5p is reduced. The objectives of this study were to determine the normal function of Let-7b-5p in human trophoblast cells, to examine whether the ssRNA sensors, Toll-like receptor (TLR) 7 and/or TLR8 are mediators of trophoblast Let-7b-5p function, and whether disruption of this pathway promotes a preeclampsia-like phenotype in the trophoblast. MethodsThe human first trimester trophoblast cell line, Sw.71, was transfected with a Let-7b- 5p mimic, a Let-7b-5p inhibitor, or scramble control. Cells were treated with or without the TLR7 inhibitor IRS661 or the TLR8 inhibitor CUCPT9a. Trophoblast migration was measured using a two-chamber assay and interactions with human endometrial endothelial cells (HEECs) was measured using a 3D matrigel model. Trophoblast anti-angiogenic sFlt-1 release was measured by ELISA and sFLT1 mRNA measured by RT-qPCR. ResultsTransfection of trophoblast cells with a Let-7b-5p mimic elevated migration through activation of TLR7 and TLR8, while in a TLR7-dependent manner, the Let-7b-5p mimic negatively regulated sFlt-1 production. Furthermore, inhibition of trophoblast Let-7b-5p reduced migration, elevated FLT1 mRNA expression and sFlt-1 release, and reduced trophoblast-endometrial endothelial cell interactions. ConclusionsThis study highlights a role for TLR7/TLR8-activating Let-7b-5p in promoting normal trophoblast function and endothelial interactions and that disruption in this miR-driven signaling pathway may be relevant to processes driving a pre-eclamptic placental phenotype. HighlightsTrophoblast migration is positively driven by Let-7b-5p activating TLR7 and TLR8 Let-7b-5p, via TLR7, negatively regulates trophoblast anti-angiogenic sFlt-1 production. Inhibition of trophoblast Let-7b-5p reduces trophoblast migration and normal interactions with endometrial endothelial cells, while sFlt-1 production is elevated. TLR7/TLR8-activating Let-7b-5p promotes normal trophoblast function and endothelial interactions and disruption in this miR-driven signaling pathway may promote a preeclamptic placental phenotype.

Direct experimental analysis of the mammalian oviduct is constrained by limited tissue access and the short lifespan of ex vivo preparations. Extracellular matrix-embedded three-dimensional epithelial organoids provide longer-term in vitro models. However, their inward-facing apical surface and the absence of supporting stromal cells limit physiological studies of the oviduct, including ciliary activity and maternal-embryonic interactions. Here, we provide a step-wise protocol detailing the generation of mouse and human oviductal assembloids in which epithelial cells form an outward-facing (apical-out) layer around a stromal core. Epithelial and stromal cells from adult mouse oviducts or human Fallopian tubes are isolated, expanded separately, and subsequently aggregated in a rotational culture system. The protocol also outlines morphological and immunostaining criteria for confirming cellular organization, whole-mount detection of external cilia, measurement of ciliary beat frequency, and co-culture of mouse assembloids with preimplantation embryos. Mouse and human assembloids retained epithelial and stromal identity and displayed cilia at the accessible outer surface. In a proof-of-concept experiment, embryos co-cultured with the assembloids developed to blastocysts at a rate similar to that of in vivo-derived blastocysts. This reductionist system provides a straightforward and tractable model to investigate oviduct physiology and embryo-maternal communication while allowing direct manipulation and observation of the epithelial interface. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/743297v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@1917a7borg.highwire.dtl.DTLVardef@41d7org.highwire.dtl.DTLVardef@e2bf98org.highwire.dtl.DTLVardef@90c9f3_HPS_FORMAT_FIGEXP M_FIG C_FIG SummaryThe protocol for generating mouse and human oviductal assembloids by combining epithelial and stromal cells for studying oviductal function in an in vitro setting.

Known for their rapid water surface locomotion, whirligig beetles (Gyrinidae) are also fast divers. They can transition from the surface to underwater swimming in under 100 ms. Diving requires them to generate sufficient hydrodynamic torque to break the water surface and reorient the body. However, the mechanism by which whirligigs create the necessary pitch-down torque is unknown. Here, we show that their diving is achieved by bending the abdomen. The inertial hydrodynamic pressure on the flexed abdomen generates the torque necessary for surface breaking and body rotation. The torque is maximized at an abdominal angle of 45{degrees}, whereas for effective diving, whirligigs display a preferential abdominal angle of around 28{degrees}, closely aligning with the angle that maximizes the torque-to-drag ratio. This abdominal angle is optimized by balancing torque generation with the drag penalty. Our findings inspire a mechanism for surface-to-underwater transition, offering design principles for multimodal robots capable of locomotion across the air-water interface.

Cancer survival rates increase with earlier diagnosis. However, many cancers are diagnosed only after symptoms develop, in the later stages of cancer progression. We need a diagnostic tool that can detect cancer earlier. Circulating tumour cells (CTCs) are cells that detach from the main tumour and can enter the bloodstream. The capture and analysis of CTCs can provide an early indicator of cancer. However, rarity of CTCs in blood makes their efficient capture challenging. Inertial microfluidics can be utilised for a label-free separation of CTCs from white blood cells (WBCs) by manipulating cells in the microchannel based on cell properties, achieving good separation performance. Inertial microfluidic devices mainly rely on size-based separation. However, residual WBC carryover limits complete separation. Here, we show that cell mechanical heterogeneity plays a large role in the separation process and should be considered in the design of these devices. We simulate the migration dynamics of CTCs and WBCs in a straight microchannel using a 3D lattice-Boltzmann-immersed-boundary-finite-element solver. Our results demonstrate that WBC migration behaviour changes depending on the deformability of a CTC. The size and deformability of the cells have been shown to determine the cell-specific heteroclinic orbits leading to different interaction types, these interactions alter WBC migration resulting in more/less WBC carryover. This work highlights that both cell-specific heteroclinic orbits and single cell migration rates should be considered in the design of inertial microfluidics for separation.

Non-genetic adaptation enables cancer cells to alter their phenotype under stress without requiring new mutations. However, the mechanisms by which electrical, mechanical, and hypoxic cues combine to shape this process in 3D tissues remain poorly understood. This work presents an agent-based tumor model that integrates vascular oxygen supply, a globally imposed electric field, mechanically mediated crowding and compression cues, phenotype transitions, cell growth, mitosis, death, and inheritance of adaptive memory across division. The simulated tumors exhibit a three-stage trajectory consisting of necrosis onset, transient collapse of live mass, and partial regrowth accompanied by progressive accumulation of adapted cells. Continuous electrical stimulation produces a dose-dependent reduction in live mass while markedly increasing the adapted fraction, with comparatively limited changes in final necrotic burden. This response is strongly conditioned by mechanics and reshapes (and is reshaped by) adaptive capacity. Pulsed stimulation further shows that, in the model, electric field amplitude and temporal schedule jointly determine memory phenomena, phenotypic diversification, and growth recovery. These results show that coupling local oxygen availability, mechanical constraints, electrical forcing, and history-dependent phenotype transitions can generate distinct tissue-level patterns of phenotypic heterogeneity. Both stimulus magnitude and temporal protocol influenced the resulting population structure, suggesting that the history of physical stress may be an important determinant of adaptive dynamics in spatially organized tumor models.

Objective: Tumor protein D52 (TPD52) is aberrantly expressed in various malignancies; however, its systematic expression profile, prognostic significance, tumor microenvironment associations, and functional mechanisms in breast cancer remain poorly defined. Methods: GEO and TCGA breast cancer expression datasets were integrated to identify differentially expressed genes (DEGs). We evaluated the diagnostic performance of TPD52 via protein-protein interaction (PPI) network analysis, GO/KEGG enrichment analysis and eleven machine learning algorithms. Immunohistochemistry verified TPD52 protein expression in clinical specimens, and Kaplan-Meier analysis assessed its prognostic significance. Analysis of single-cell transcriptomic data (GSE176078) revealed the cell-type-specific distribution of TPD52 and its intercellular communication network in the breast cancer microenvironment. Weighted gene co-expression network analysis (WGCNA) explored relationships between TPD52 and tumor microbiome, hypoxia signatures as well as microsatellite instability. Moreover, TPD52 was knocked down by siRNA in MCF7 cells, and its impacts on cell migration, invasion, proliferation and the MAPK/ERK signaling pathway were examined through wound healing, Transwell, CCK-8 and Western blot assays. Results: TPD52 was significantly overexpressed in breast cancer tissues at both the mRNA and protein levels. A random forest-based diagnostic model demonstrated high accuracy across multiple datasets. Kaplan-Meier analysis revealed that elevated TPD52 expression was associated with longer overall survival in specific subgroups, including the basal-like subtype, invasive lobular carcinoma, and N0/N1 stages. Single-cell analysis showed that TPD52 was predominantly expressed in tumor epithelial cells, which occupied a central position within the intercellular communication network. WGCNA further identified a positive correlation between TPD52 and a hypoxia-associated microbial module, as well as a negative correlation with a microsatellite instability module. In vitro functional assays confirmed that TPD52 knockdown significantly suppressed the migration, invasion, and proliferation of MCF7 cells, and led to reduced p-ERK1/2 protein levels. Conclusion: TPD52 promotes the malignant phenotypes of breast cancer cells through activation of the MAPK/ERK signaling pathway, yet its prognostic significance is subtype- and microenvironment-dependent. These findings establish TPD52 as both a diagnostically valuable biomarker and a mechanistically defined potential therapeutic target.

In breast cancer, collagen fiber alignment and the second harmonic generation forward-to-backward ratio (F/B), an optical measurement sensitive to fibril-scale organization within collagen fibers, have each been associated with metastatic outcome. Although both are measured at the tumor-stromal interface, in vitro studies have largely examined them separately, because experimental systems have not allowed the two to be varied independently. To address this technical gap, we used a microfluidic biofabrication approach to generate paired aligned and unaligned regions within 3D collagen hydrogels via extensional strain and varied measured F/B across gels by changing the pre-gel pH. The resulting library covered alignment values reported in breast tumors and F/B values associated with poorer metastatic outcome in invasive ductal carcinoma at matched matrix stiffness, pore diameter, and fiber fraction. In MDA-MB-231 cells, alignment biased migration along the fiber axis without changing migration speed, as expected, but the magnitude of the contact guidance response varied with measured F/B. In contrast, MCF-7 cells showed little overall contact guidance, yet migrated ~30% faster in high F/B than low F/B gels in both aligned and unaligned regions. Together, these results show that cells migrated differently in matrices with similar fiber alignment. Thus, including measured F/B may provide additional information to help anticipate how cells migrate in collagen environments that appear similar based on alignment alone.

Background: The Central Brain Tumor Registry of the United States (CBTRUS) uses a histology grouping model based on the World Health Organization (WHO) to classify cancer registry records for clinically relevant statistical reporting. Methods: CBTRUS, together with its consulting neuropathologists, reviewed and aligned its histology groupings with the 2021 WHO Classification update. Obsolete histology nomenclature along with their International Classification of Diseases for Oncology 3rd edition (ICD-O-3) codes were identified, currently included histologies were reclassified as appropriate, and new codes found in 2021 WHO were incorporated. An evaluation was conducted of the frequency of histology codes affected in the reclassification process, as well as incidence and survival pre- and post- reclassification of CBTRUS Tumor Type Groupings. Results: After review of the CBTRUS grouping scheme, 205 codes were reclassified and 2 new codes were incorporated. Tumor type groups most affected were those classified as glioma. Reclassification resulted in 167,038 of 491,804 (34%) cases having a grouping reclassification or reporting change, indicating that the 2021 revision of the WHO Classification has significantly impacted the collection and reporting of primary b CNS tumors. Conclusion: This work demonstrates the need to be responsive to changes in classification and coding for statistics to reflect real-world clinical use. This will require collaboration from all parties to have the ability to reconcile clinical practices and surveillance requirements.

Solid tumors are known to be refractory to treatment due to a poorly perfused microenvironment that blocks immune cell infiltration and effective drug delivery. Histotripsy is a non-invasive focused ultrasound modality that generates cavitation microbubbles to mechanically disrupt solid tumors, resulting in decreased hypoxia and stimulation of tumor-targeted adaptive immune responses. In this study, we aim to investigate whether post-histotripsy hypoxia reduction and cytotoxic immune cell infiltration are associated with normalization of tumor vasculature and enhanced perfusion. Structural analysis of both treated and contralateral off-target tumors following partial histotripsy revealed significant vascular remodeling, enhanced vascular integrity, and decreased vascular leakage indicative of vascular normalization in multiple in vivo models of melanoma, hepatocellular carcinoma, and pancreatic adenocarcinoma. These effects appeared antigen-specific, as no remodeling was observed in contralateral off-target tumors of discordant pathology. Mechanistically, CXCR3+CD8+ T cells played a role in mediating these vascular changes, as genetic knockout of CD8 and pharmacological antagonism of CXCR3 impaired both remodeling and normalization. Additionally, significant changes in endothelial CXCR4 and Angiopoietin-1 and -2 expressions were observed following histotripsy, indicating their potential involvement in promoting vascular normalization and remodeling. Significant vascular remodeling was accompanied by enhanced tumor perfusion and intratumoral delivery of chemotherapeutic agents and therapeutic monoclonal antibodies. These findings suggest that histotripsy not only creates a more favorable microenvironment for immunotherapy, but also optimizes drug delivery into solid tumors. Combinatorial approaches using histotripsy with chemotherapy or immunotherapy may be a novel therapeutic strategy to overcome current limitations of conventional solid tumor therapies.

Devireddy et al. [1] previously showed that an enthalpy-based, macroscale model simulated tissue freezing histories are in close agreement with a coupled model incorporating cellular water transport and intracellular ice formation (IIF). That comparison, however, was performed for a limited set of tissue geometries, cooling conditions, and biophysical parameters. Here, we revisit that conclusion by reimplementing the published model from its governing equations and systematically expanding the parameter space to determine when microscale processes alter the predicted macroscale freezing response. We incorporate both surface catalyzed nucleation (SCN) and volume catalyzed nucleation (VCN) of intracellular ice with cellular osmotic dehydration and examine a broad range of tissue dimensions, cooling rates, convective boundary conditions, membrane permeabilities, cell sizes, activation energies, intracellular water fractions, and nucleation rates. Linearization of the cellular water transport equation about osmotic equilibrium yields an osmotic relaxation timethat can be compared with the local residence time of tissue undergoing phase change. Their ratio defines a dimensionless group, that organizes the transition between regimes in which the uncoupled enthalpy formulation and the coupled micro and macroscale formulation produce similar or substantially different results. Across the one-dimensional parameter space examined here, the two models remain within a prescribed thermal-error bound for the dimensionless group below approximately 0.1, whereas the discrepancy increases systematically above this threshold. Model divergence also depends on intracellular ice nucleation, i.e., when nucleation is sufficiently slow, cellular water transport can become rate limiting for latent heat release. Conversely, sufficiently rapid intracellular ice formation reduces the macroscopic discrepancy by providing an additional pathway for latent-heat release. Multidimensional simulations further show that geometry alone can move a nominally conventional freezing protocol into the coupled regime. In particular, multidirectional cooling can reduce the local residence time sufficiently to produce substantial differences in predicted frozen volume even when the corresponding thermal histories appear similar. Finally, we formulate an inverse approach for estimating IIF parameters from tissue scale thermal histories. Synthetic simulations indicate that parameter recovery is feasible within a finite range of cooling conditions, providing a testable strategy for future experimental measurements. Together, these results provide a mechanistic criterion for deciding when microscale biophysical processes must be retained in macroscale tissue-freezing models.

Healing of the gastrointestinal (GI) tract following surgical interventions is governed by coupled mechanobiological processes and may lead to severe complications such as perforation or stricture formation. A first comprehensive mechanobiological modeling framework of GI healing is herein proposed. The framework addresses two clinically relevant applications of bioprinting: endoscopic treatment of GI tissue defects and bioprinting-assisted surgical anastomosis. Tissue remodeling is based upon a hyperelastic material model with fiber dispersion coupling the spatiotemporal reaction diffusion dynamics of fibroblasts and cytokines with collagen deposition, reorientation, and plastic deformation. An active stress formulation drives fibroblasts and myofibroblast contraction while a multiplicative decomposition approach is adopted for collagen remodeling as a permanent change. The governing equations are discretised in time with an implicit Euler scheme, finite element in space and solved by a staggered algorithm implemented in the open-source platform FEniCS. Numerical simulations show that the initial collagen fibers content and orientation strongly influence fibroblast infiltration and scar contracture formation. The study quantifies the advantage of having a collagen bioprinted architecture aligned with tissue fibers, to reduce structural remodeling distortion. The model also predicts a strong correlation between collagen deposition and luminal burst pressure during the recovery of mechanical integrity in GI anastomosis.

The tumor microenvironment plays a pivotal role in tumor development, harboring elements such as endothelial cells, immune cells, fibroblasts, and soluble factors such as transforming growth factor-{beta} (TGF-{beta}) family. TGF-{beta} family regulates cell development and promotes tumor invasion, metastasis, angiogenesis, and endothelial-to-mesenchymal transition (EndoMT). Here, we investigate the effects of TGF-{beta} signaling on vascular remodeling using a three-dimensional (3D) vascular network in a microfluidic device. Using both a co-culture (3D-Co) and simplified endothelial monoculture (3D-CM), we demonstrate that TGF-{beta} signaling reduces the quality and functionality of the vasculature by regressing them. In addition, we observed the upregulation of EndoMT-related markers in mRNA and protein expressions, suggesting the induction of EndoMT in 3D vascular networks. The increased vascular permeability stimulated by TGF-{beta}2 also supports the loss of endothelial identity in the 3D-Co. Transcriptomic analysis revealed the coordinated activation of pathways associated with cell migration and EndoMT, along with the suppression of cell cycle progression. A comparative analysis of two-dimensional (2D) and 3D cultures revealed a fundamentally distinct endothelial response to TGF-{beta}2 in the 3D context, including metabolic reprogramming. These findings demonstrate that the 3D microenvironment critically modulates endothelial responses to TGF-{beta} and enables the emergence of vascular phenotypes not captured in 2D systems. This study provides a more physiologically relevant platform to investigate endothelial dysfunction and vascular remodeling.

Pericytes (PCs) have recently emerged as critical regulators of cerebral blood flow (CBF) and represent a promising therapeutic target for various cerebrovascular pathologies. Given the complex array of biochemical and mechanical stimuli these cells integrate, a multiscale modeling framework is essential to quantify the impact of selective interventions on pericyte contractile machinery and blood flow restoration. Here, we introduce a computational framework to evaluate capillary pericyte responses across diverse experimental interventions and conditions (ex vivo and in vivo). To capture pharmacological modulation of the contractile apparatus, we developed a homogeneous intracellular model that incorporates key properties of robust control systems. In this framework, vascular tone generation depends strictly on intracellular calcium concentration (Ca2+), which emerges from a complex electrochemical equilibrium established by transmembrane ion (Na+, K+, Cl-) gradients, luminal mechanical forces, and external ligand concentrations. The resulting fraction of phosphorylated cross-bridges generates contractility, which is integrated into the strain energy function governing the constitutive behavior of the vascular wall. The model was successfully validated across four distinct experimental and pharmacological interventions (including pinacidil, high external K+, U46619, and nimodipine), demonstrating close agreement with observed ex vivo and in vivo vascular responses. By establishing a quantitative bridge between pericyte electrophysiology and microvascular mechanics, this framework provides a valuable foundation for evaluating targeted therapeutic strategies to alleviate tissue ischemia in stroke and vascular dementia.

Biochemical Systems Theory (BST) represents nonlinear biochemical rate laws by local power-law approximations in logarithmic concentration coordinates. First-order coefficients are elasticities, whereas higher-order derivatives describe local log-synergism and its variation. Ordinary higher derivatives, however, are not tensorial under nonlinear reparameterizations and can mix biochemical response structure with coordinate artifacts. We formulate a covariant hierarchy, cBST1-cBST3, on a positive operating-point space equipped with a declared reference connection. cBST1 recovers classical elasticities in a flat logarithmic chart, cBST2 is the covariant Hessian of the log-response, and cBST3 is the symmetrized covariant derivative of cBST2. The framework is quantitatively evaluated using three representative rate laws from the curated yeast glycolysis model BIOMD0000000064: glucose transport, glucose phosphorylation, and phosphofructokinase. For 10,000 finite log-concentration perturbations at each of five radii, cBST2 reduced the cBST1 log-rate root-mean-square error by 96.6-98.6% at the largest tested radius, and cBST3 provided a further 68.4-98.1% reduction. The contracted cBST2 and cBST3 terms strongly predicted the corresponding lower-order truncation errors. Under the nonlinear transformation qi = sinh(ui), covariant contractions agreed across coordinates to within a 95th-percentile relative error of 1.2 x 10-13, whereas ordinary higher derivatives showed order-unity coordinate mismatches. Supplementary analytic tests recovered the expected second-, third-, and fourth-order truncation-error scaling. These results show that cBST1-cBST3 are not only coordinate-consistent descriptors but also practical diagnostics of where local power-law approximations require higher-order correction.

Cellular systems must act robustly to maintain organismal health, including maintaining biophysical properties that allow for appropriate cellular function, and adapting these properties through changes such as those that occur during cell division. However, we still lack tools to measure many of these physical properties with precision in the living cell. For example, the mechanical properties of the nucleoplasm, the fluid-like substance that fills the nucleus, have not been fully characterized. To investigate these properties, we have turned to the fission yeast Schizosaccharomyces pombe (S. pombe), a well-established, genetically tractable model organism that has been used extensively for studying a variety of cell biophysical processes and structures, including the cytoskeleton and cell division. It is an apt system for studying how the nucleus adapts over the course of the cell cycle, since it undergoes closed mitosis, where the nuclear envelope remains intact during cell division. Studying nucleoplasm properties over the course of closed mitosis may help reveal how nuclear volume, shape, surface area expansion, and chromosome segregation are linked and coordinated. To measure nucleoplasm material properties in S. pombe, we have paired Fluorescence Correlation Spectroscopy (FCS) with a photoswitchable fluorophore, enabling fine control over fluorescent intensity inside live cells. We infer material properties from FCS measurements, while the photoswitchable probe enables confocal imaging in conjunction with these measurements, yielding corresponding information about cellular state and dynamics. Interestingly, we find that nucleoplasm material properties do not vary significantly over the cell cycle. Future studies will use this tool to examine how diverse molecular and genetic perturbations alter nucleoplasmic properties, providing insight into how these properties maintain nuclear function and protect genomic integrity over the cell cycle and during development.