Shear stress-initiated signaling and its regulation of endothelial function

Fluid Shear Stress-Regulated Vascular Remodeling: Past, Present, and Future

The vascular system remodels throughout life to ensure adequate perfusion of tissues as they grow, regress, or change metabolic activity. Angiogenesis, the sprouting of new blood vessels to expand the capillary network, versus regression, in which endothelial cells die or migrate away to remove unneeded capillaries, controls capillary density. In addition, upstream arteries adjust their diameters to optimize blood flow to downstream vascular beds, which is controlled primarily by vascular endothelial cells sensing fluid shear stress (FSS) from blood flow. Changes in capillary density and small artery tone lead to changes in the resistance of the vascular bed, which leads to changes in flow through the arteries that feed these small vessels. The resultant decreases or increases in FSS through these vessels then stimulate their inward or outward remodeling, respectively. This review summarizes our knowledge of endothelial FSS-dependent vascular remodeling, offering insights into potential therapeutic interventions. We first provide a historical overview, then discuss the concept of set point and mechanisms of low-FSS-mediated and high-FSS-mediated inward and outward remodeling. We then cover in vivo animal models, molecular mechanisms, and clinical implications. Understanding the mechanisms underlying physiological endothelial FSS-mediated vascular remodeling and their failure due to mutations or chronic inflammatory and metabolic stresses may lead to new therapeutic strategies to prevent or treat vascular diseases.

KLF10 Induced by Hypothermic Machine Perfusion Alleviates Renal Inflammation Through BIRC2 /Noncanonical NF-κB Pathway

BACKGROUND

Hypothermic machine perfusion (HMP) is becoming the main preservation method for donation after circulatory death (DCD) kidneys. It can provide continuous flow and form shear stress (SS) upon endothelial cells (ECs), thereby regulating EC injury. Krüppel-like factor 10 (KLF10) has been shown to lessen vascular damage. However, how SS and KLF10 impact HMP-regulated injury is unclear.

METHODS

In this study, we investigated the influences of KLF10 on HMP in animal models and human renal biopsy and explored how SS affected KLF10 expression in a parallel-plate flow chamber system. Chromatin Immunoprecipitation sequencing and luciferase assay were performed to seek the target genes of KLF10. The influences of KLF10 on HMP-regulated injury were investigated by transfecting si-KLF10 adeno-associated virus serotype 9 into rat kidneys. The molecular expression was examined using immunofluorescence staining, Western blotting, and quantitative polymerase chain reaction.

RESULTS

Our results show KLF10 expression was augmented in human, rabbit, and rat DCD kidneys after HMP. HMP improved ECs and tubule injury and attenuated inflammation; however, the knockdown of KLF10 reversed this effect. SS regulated KLF10 expression in ECs by affecting F-actin, and KLF10 could maintain ECs homeostasis. Chromatin Immunoprecipitation sequencing and luciferase assay revealed that baculoviral inhibitor of apoptosis protein repeat-containing 2 (BIRC2) is a target gene of KLF10. Furthermore, BIRC2 linked to nuclear factor kappa B (NF-κB)-inducing kinase, induced NF-κB)-inducing kinase ubiquitination, and resulted in inhibiting the noncanonical NF-κB pathway.

CONCLUSIONS

SS can mediate KLF10 expression, whereas HMP can protect against warm ischemic injury by reducing inflammation via KLF10/BIRC2/noncanonical NF-κB pathway. Therefore, KLF10 might be a novel target for improving DCD kidney quality.

Computational construction and design optimization of a novel tri-tube heart valve

A finite-element-based algorithm for the in silico construction of a novel tri-tube heart valve was developed to facilitate optimization of the leaflet geometry. An anisotropic hyperelastic model fitted to high-strain rate planar equibiaxial tension and compression data was used to approximate the nonlinear and anisotropic material behavior of biologically-engineered tubes and simulate valve closure under steady back pressure and steady forward flow. Four metrics were considered to evaluate valve performance in simulated closure: coaptation area, regurgitation area, pinwheel index, and prolapse area. Response surfaces revealed competing objectives between metrics for a valve of target 24 mm diameter in terms of two design parameters, tube diameter and leaflet height. A multi-objective genetic algorithm determined an intermediate tube diameter and leaflet height (16 mm and 11 mm, respectively) of the design space as optimal. Additionally, steady flow simulations were performed using two-way fluid-structure interaction with selected designs to examine washout behind leaflets with particle tracking. One design close to the optimal point for valve closure indicated washout for particles initially distributed behind leaflets. Though comprehensive valve design optimization requires flow analysis over multiple valve cycles to capture all effects associated with flow, this methodology based on diastolic state geometry optimization followed by steady washout analysis reduces the space of design variables for further optimization.

Impacts of Physical Inactivity Models on Endothelial Function: A Systematic Review

BACKGROUND

Endothelial dysfunction is associated with cardiovascular disease and cardiac events. Numerous studies demonstrate that a reduction in physical activity/exercise levels are associated with poor endothelial function. Yet, these studies use a plethora of models to mimic reduced activity levels which may have widely different results on endothelial function. It is pertinent to collectively review these articles to provide a comprehensive understanding of the impact of reduced activity on vascular health, as endothelial function is one of many factors that influences vascular tone.

OBJECTIVE

The purpose of this systematic review is to examine and synthesize the current literature regarding the effects of acutely (≤ ~ 2 months) reducing physical activity on endothelial function.

METHODS

This systematic review contains a search of two databases (PubMed, Web of Science) conducted by two reviewers. After screening and review, the search yielded 20 studies that were appraised and reviewed.

RESULTS

Articles were separated into four categories based on the type of inactivity intervention: reduction in daily physical activity interventions, detraining (removal of exercise) interventions, bed rest interventions, and immobilization interventions. Acute physical inactivity interventions were largely shown to reduce upper and lower limb artery flow-mediated dilation and lower limb microvascular function.

CONCLUSION

The results indicate that those studies with increased time spent in inactivity, as well as increased severity of inactivity, were more likely to have negative endothelial function outcomes. Future research should examine differences in the severity of physical inactivity interventions regarding endothelial function.

METTL3 mediates atheroprone flow-induced glycolysis in endothelial cells

Atheroprone flow-increased glycolysis in vascular endothelial cells (ECs) is pivotal in EC dysfunction and the initiation of atherosclerosis. Methyltransferase 3 (METTL3) is a major m6A methyltransferase for RNA N6-mehtyladenosine (m6A) modifications to regulate epitranscriptome and cellular functions. With the atheroprone flow upregulating METTL3 and m6A RNA hypermethylation, we investigate the role of METTL3 in atheroprone flow-induced glycolysis in ECs in vitro and in vivo. Compared to pulsatile shear stress (PS, atheroprotective flow), oscillatory shear stress (OS, atheroprone flow) increases METTL3 expression to enhance the m6A modifications of mRNAs encoding HK1, PFKFB3, and GCKR, which are rate-limiting enzymes of glycolysis. These augmented m6A modifications increase the expressions of HK1 and PFKFB3 while decreasing GCKR, resulting in elevated EC glycolysis, as revealed by seahorse analysis. Moreover, a stimulated Raman scattering (SRS) imaging study demonstrates the elevation of glucose incorporation into de novo synthesized lipids in ECs under atheroprone flow in vitro and in vivo. Empagliflozin, a sodium-glucose cotransporter-2 inhibitor (SGLT2i) drug, represses METTL3 expression, thereby mitigating OS-induced glycolysis in ECs. These data suggest mechanisms by which METTL3 links EC mechanotransduction with metabolic reprogramming under atherogenic conditions.

Probing Shear-Induced Endothelial Activation in Vascular Conditions Using On-Chip Models

Hemodynamic fluctuations at vessel bifurcation impact the development of atherosclerosis and aneurysms. A novel glass capillary tube-based lithography-free technique was used for fabricating vessel bifurcations with stenosis and aneurysm at the junction of bifurcation to determine the endothelial response to arterial shear rates in vitro. At variable shear rates of 1-2000 s-1, representative of conditions in the aorta, the endothelial cell responses under flow disturbances encountered in stenosed and aneurysmal vessels were modeled. Mechanical disturbances induce greater endothelial activation at stenosis, while increased VE-cadherin expression deters activation at dilations. The endothelial responses to disturbed flow were better observed at the area of bifurcation, where the increase in shear forces and reduced pressure marginally compensated for cellular activation. The comparative model was established using an image analysis approach for the assessment of endothelial responses toward disease progression at bifurcations. No significant differences in endothelial markers were observed under inflammatory stress and physiologically relevant mechanical stresses due to compensatory effects of inflammatory cytokines inducing NF-κβ activation, as seen using this frugal approach.

High Hcy regulates fluid shear stress pathway activity through histone H3K79 homocysteinylation in hyperhomocysteinemia-related child hypertension

BACKGROUND

The rise of hypertension in children has been increasingly associated with hyperhomocysteinemia (HHcy), which is recognized as a major risk factor. However, the underlying mechanisms linking homocysteine and hypertension (termed HHYP) are not fully understood.

METHODS

This study utilized plasma samples from 27 control children and 27 children with HHYP (aged 8 ~ 16 years) for TMT6-labeled proteomic quantification, identifying significant altered proteins. Bioinformatics analysis revealed pathway alterations. Verification was carried out via parallel reaction monitoring (PRM) and western blot (WB) analyses. Additionally, a rat model of HHYP induced by high methionine diets, and umbilical vein endothelial cell models exposed to high homocysteine (hcy) levels were developed to investigate the molecular underpinnings further. Protein expression changes and epigenetic modifications were assessed using WB, immunohistochemistry (IHC), and ChIP-qPCR techniques.

RESULTS

Key findings indicated that 357 proteins and 69 pathways were altered in children with HHYP. Specifically, 12 proteins within the fluid shear stress and atherosclerosis (FSSA) pathway showed differential expression, including the downregulation of TRX1 and GPX1 and the upregulation of ICAM1. The same expression patterns were noted in both the HHYP rat aortic tissues and the high hcy cultured endothelial cells. Moreover, elevated H3K79hcy modification levels were observed alongside epigenetic regulation of genes related to the FSSA pathway. Importantly, folic acid (FA), a medication frequently used in the clinical treatment of HHYP, has been demonstrated to effectively reverse H3K79hcy modifications and restore the disrupted FSSA pathway in both animal models and cell cultures.

CONCLUSIONS

The present study suggests that HHcy may contribute to hypertension through the epigenetic dysregulation of the FSSA pathway mediated by H3K79hcy. Furthermore, the pediatric proteomics data gleaned from this study offer new clinical insights into the pathophysiology of HHYP in children.

Nailfold capillary patterns in ballgame and endurance athletes

Purpose

Nailfold capillary patterns can be observed noninvasively using light microscopy. Nailfold capillaries are straight, U-shaped, and densely looped in healthy individuals and may be altered by disease or lifestyle factors, such as diet. However, the effects of daily physical activity and exercise training on nailfold capillary patterns remain unclear. This study aimed to examine the effects of exercise training on nailfold capillary patterns by investigating these patterns in endurance athletes, ballgame athletes, and sedentary healthy men.

Methods

Five healthy men participated in nailfold capillary pattern measurements on three consecutive days to test the reproducibility and bilateral differences in the nailfold capillary loop density, length, and width measured using light microscopy and a commercial analysis system. The nailfold capillaries of 10 endurance athletes (endurance group; eight long-distance runners and two triathletes), 10 ballgame athletes (ballgame group; seven soccer players and three basketball players), and nine sedentary healthy men (sedentary group) were then examined using light microscopy.

Results

The day-to-day coefficient of variation for the nailfold capillary loop density, length, and width were 4.9% ± 1.6%, 7.5% ± 1.3%, and 4.2% ± 1.5%, respectively. No significant differences in these measurements were observed between the dominant and non-dominant hands. Nailfold capillary density was greater in the ballgame group than in the endurance and sedentary groups. Capillary loop length was shorter in the ballgame group than in the endurance and sedentary groups. No significant differences in capillary loop density and length were observed between the endurance and sedentary groups. No significant intergroup differences were observed in capillary loop width.

Conclusion

These results suggest that the nailfold capillary patterns of male ballgame athletes differ from those of endurance athletes and sedentary healthy men. Ballgame training may affect nailfold capillary patterns in sedentary healthy men.

Differential expression of endothelial derived galectins in response to shear stress

BACKGROUND

Endothelial cells function as mechanosensors, dynamically altering their functional response based on varying shear stress/flow patterns to maintain vascular homeostasis. Disturbed flow leads to endothelium dysfunction, promoting conditions such as atherosclerosis. Understanding the molecular impact of flow is crucial for the development of new therapeutic targets for vascular diseases. Galectins have been implicated in vascular diseases, specifically their role in inflammation. However, the regulation of endothelial galectins by shear stress remains unexplored.

METHODS

Galectin gene and protein expression were analysed from publicly available datasets or in human umbilical endothelial cells (HUVEC) and human arterial endothelial cells (HAEC) cultured under either shear stress induced by orbital shaking or static conditions by qPCR, immunofluorescence imaging and ELISA.

RESULTS

Laminar shear stress upregulated LGALS9 and downregulated LGALS1, while disturbed flow reversed these effects. Complex shear environments significantly increased Gal-3 and Gal-9 expression at both gene and protein levels, with distinct variations in surface expression and secretion. In vivo single-cell RNA sequencing (scRNAseq) revealed reduced Lgals9 expression in endothelial cells exposed to disturbed flow in carotid artery ligation models compared to laminar flow.

SIGNIFICANCE

These findings highlight that endothelial galectin expression is shear-regulated, which has significant implications for understanding galectin biology and there potential as therapeutic targets in vascular diseases influenced by shear stress.

Fluid-structure-growth modeling in ascending aortic aneurysm: capability to reproduce a patient case

Predicting the evolution of ascending aortic aneurysm (AscAA) growth is a challenge, complicated by the intricate interplay of aortic geometry, tissue behavior, and blood flow dynamics. We investigate a flow-structural growth and remodeling (FSG) model based on the homogenized constrained mixture theory to simulate realistic AscAA growth evolution. Our approach involves initiating a finite element model with an initial elastin insult, driven by the distribution of Time-Averaged Wall Shear Stress (TAWSS) derived from computational fluid dynamics simulations. Through FSG simulation, we first calibrate the growth and remodeling material parameters to reproduce the growth observed on a patient-specific case. Then, we explore the influence of two critical parameters: the direction of the inlet jet flow, which affects the zone of significant TAWSS, and prestretch, which impacts the tissue homeostatic state. Our results show that calibrating material parameters, inlet flow direction, and prestretch allows to reproduce the observed growth, and that prestretch calibration and inlet flow direction significantly influence the simulated growth pattern. Our workflow can be applied to additional patient cases to confirm these tendencies and progress toward a predictive tool for clinical decision support.

Multifaceted Role of Notch Signaling in Vascular Health and Diseases

Notch signaling is evolutionarily conserved from Drosophila to mammals and it functions as an essential modulator of vascular growth and development by directing endothelial cell specification, proliferation, migration, arteriovenous differentiation, inflammation, and apoptosis. The interplay between Notch and other signaling pathways plays a homeostatic role by modulating multiple vascular functions, including permeability regulation, angiogenesis, and vascular remodeling. This review explores current knowledge on Notch signaling in vascular development, homeostasis, and disease. It also discusses recent developments in understanding how endothelial Notch signaling affects vascular inflammation via cytokines or aberrant shear stress in endothelial cells while addressing the reciprocal relationship between Notch signaling and inflammation.

Biophysical and Biochemical Roles of Shear Stress on Endothelium: A Revisit and New Insights

Hemodynamic shear stress, the frictional force exerted by blood flow on the endothelium, mediates vascular homeostasis. This review examines the biophysical nature and biochemical effects of shear stress on endothelial cells, with a particular focus on its impact on cardiovascular pathophysiology. Atherosclerosis develops preferentially at arterial branches and curvatures, where disturbed flow patterns are most prevalent. The review also highlights the range of shear stress across diverse human arteries and its temporal variations, including aging-related alterations. This review presents a summary of the critical mechanosensors and flow-sensitive effectors that respond to shear stress, along with the downstream cellular events that they regulate. The review evaluates experimental models for studying shear stress in vitro and in vivo, as well as their potential limitations. The review discusses strategies targeting shear stress, including pharmacological approaches, physiological means, surgical interventions, and gene therapies. Furthermore, the review addresses emerging perspectives in hemodynamic research, including single-cell sequencing, spatial omics, metabolomics, and multiomics technologies. By integrating the biophysical and biochemical aspects of shear stress, this review offers insights into the complex interplay between hemodynamics and endothelial homeostasis at the preclinical and clinical levels.

Harnessing native blueprints for designing bioinks to bioprint functional cardiac tissue

Cardiac tissue lacks regenerative capacity, making heart transplantation the primary treatment for end-stage heart failure. Engineered cardiac tissues developed through three-dimensional bioprinting (3DBP) offer a promising alternative. However, reproducing the native structure, cellular diversity, and functionality of cardiac tissue requires advanced cardiac bioinks. Major obstacles in CTE (cardiac tissue engineering) include accurately characterizing bioink properties, replicating the cardiac microenvironment, and achieving precise spatial organization. Optimizing bioink properties to closely mimic the extracellular matrix (ECM) is essential, as deviations may result in pathological effects. This review encompasses the rheological and electromechanical properties of bioinks and the function of the cardiac microenvironment in the design of functional cardiac constructs. Furthermore, it focuses on improving the rheological characteristics, printability, and functionality of bioinks, offering valuable perspectives for developing new bioinks especially designed for CTE.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

The application of computational fluid dynamics in hepatic portal vein haemodynamics research: a narrative review

Background and Objective

The diagnosis and treatment of many liver diseases are related to the assessment of the hepatic portal vein (PV). Noninvasive methods (medical imaging) and invasive methods (hepatic vein catheterization) are commonly used to analyse the haemodynamic information of the PV. In recent years, computational fluid dynamics (CFD) has emerged as a transformative tool in haemodynamics research, revolutionizing the understanding of blood flow behaviour, especially in various artery systems. The purpose of this review is the following: (I) introduce clinicians to CFD as a novel tool and describe its role in PV assessment; and (II) for clinicians and researchers who already use CFD, outline the progress in the application of CFD to the PV.

Methods

The English-language literature published from 1987 (when the first study supporting the study's aim appeared) to 2024 was selected for inclusion in a narrative review.

Key Content and Findings

This narrative review commences with an overview of principles of CFD and methods in PV studies, which involve model establishment, grid partitioning, boundary condition formulation, and error analysis. The focus then shifts to CFD's impact on the examination of the PV under different conditions such as portal hypertension in liver cirrhosis, PV thrombosis, post-transjugular intrahepatic portosystemic shunt (TIPS) procedure, and evaluation of the PV after liver transplantation. Finally, challenges and future directions about the CFD application in PV are outlined.

Conclusions

CFD has potential application value in PV haemodynamics, but of the few studies available, most involve only small samples. Therefore, more research is needed to clarify the feasibility and reliability of this new tool.

Fast simulation of hemodynamics in intracranial aneurysms for clinical use

BACKGROUND

A widely accepted tool to assess hemodynamics, one of the most important factors in aneurysm pathophysiology, is Computational Fluid Dynamics (CFD). As current workflows are still time consuming and difficult to operate, CFD is not yet a standard tool in the clinical setting. There it could provide valuable information on aneurysm treatment, especially regarding local risks of rupture, which might help to optimize the individualized strategy of neurosurgical dissection during microsurgical aneurysm clipping.

METHOD

We established and validated a semi-automated workflow using 3D rotational angiographies of 24 intracranial aneurysms from patients having received aneurysm treatment at our centre. Reconstruction of vessel geometry and generation of volume meshes was performed using AMIRA 6.2.0 and ICEM 17.1. For solving ANSYS CFX was used. For validational checks, tests regarding the volumetric impact of smoothing operations, the impact of mesh sizes on the results (grid convergence), geometric mesh quality and time tests for the time needed to perform the workflow were conducted in subgroups.

RESULTS

Most of the steps of the workflow were performed directly on the 3D images requiring no programming experience. The workflow led to final CFD results in a mean time of 22 min 51.4 s (95%-CI 20 min 51.562 s-24 min 51.238 s, n = 5). Volume of the geometries after pre-processing was in mean 4.46% higher than before in the analysed subgroup (95%-CI 3.43-5.50%). Regarding mesh sizes, mean relative aberrations of 2.30% (95%-CI 1.51-3.09%) were found for surface meshes and between 1.40% (95%-CI 1.07-1.72%) and 2.61% (95%-CI 1.93-3.29%) for volume meshes. Acceptable geometric mesh quality of volume meshes was found.

CONCLUSIONS

We developed a semi-automated workflow for aneurysm CFD to benefit from hemodynamic data in the clinical setting. The ease of handling opens the workflow to clinicians untrained in programming. As previous studies have found that the distribution of hemodynamic parameters correlates with thin-walled aneurysm areas susceptible to rupture, these data might be beneficial for the operating neurosurgeon during aneurysm surgery, even in acute cases.

Quantification of Blood Flow in the Carotid Bifurcation of Healthy Subjects

Locally disturbed blood flow patterns are known to create an atherogenic environment, particularly in the presence of other cardiovascular risk factors. Given the geometry of a healthy carotid artery, complex flow patterns are expected to be present. This study aims to characterize (complex) blood flow patterns and estimate flow-derived parameters in the carotid bifurcation of healthy subjects. Ultrasound-based velocity vector imaging (US-VVI) was acquired in the carotid bifurcation of 20 healthy subjects. Hemodynamic parameters, including temporal velocity profile, vector complexity (VC), vortex presence, and wall shear stress (WSS), were derived and compared between two age groups (20-30 and 65-75 years). Lower velocities and higher VC values were observed in the older age group for all timepoints. The highest presence of vortices was observed during the systolic deceleration, which was more exposed in younger subjects (5 out of 10) compared to older subjects (3 out of 9). A quick build-up and consequent resolving of the vortices was reflected by the relatively short vortex duration, with a vortex presence of 11.4% (7.9-15.6) and 13.1% (5.9-18.6) as a percentage of the cardiac cycle in younger and older subjects, respectively. Larger WSS estimates, represented as median along the complete vessel wall, were found in the younger subjects at all timestamps, except at systolic deceleration. In conclusion, the presence of complex flow patterns was confirmed in healthy subjects and multiple flow-derived hemodynamic parameters were evaluated in two age groups, providing an insight into age-related differences in hemodynamics. Aging seemed to result in higher vector complexities, whereas the presence of recirculating flow is less in older subjects.

Integrating microfluidics, hydrogels, and 3D bioprinting for personalized vessel-on-a-chip platforms

Thrombosis, a major cause of morbidity and mortality worldwide, presents a complex challenge in cardiovascular medicine due to the intricacy of clotting mechanisms in living organisms. Traditional research approaches, including clinical studies and animal models, often yield conflicting results due to the inability to control variables in these complex systems, highlighting the need for more precise investigative tools. This review explores the evolution of in vitro thrombosis models, from conventional polydimethylsiloxane (PDMS)-based microfluidic devices to advanced hydrogel-based systems and cutting-edge 3D bioprinted vascular constructs. We discuss how these emerging technologies, particularly vessel-on-a-chip platforms, are enabling researchers to control previously unmanageable factors, thereby offering unprecedented opportunities to pinpoint specific clotting mechanisms. While PDMS-based devices offer optical transparency and fabrication ease, their inherent limitations, including non-physiological rigidity and surface properties, have driven the development of hydrogel-based systems that better mimic the extracellular matrix of blood vessels. The integration of microfluidics with biomimetic materials and tissue engineering approaches has led to the development of sophisticated models capable of simulating patient-specific vascular geometries, flow dynamics, and cellular interactions under highly controlled conditions. The advent of 3D bioprinting further enables the creation of complex, multi-layered vascular structures with precise spatial control over geometry and cellular composition. Despite significant progress, challenges remain in achieving long-term stability, incorporating immune components, and translating these models to clinical applications. By providing a comprehensive overview of current advancements and future prospects, this review aims to stimulate further innovation in thrombosis research and accelerate the development of more effective, personalized approaches to thrombosis prevention and treatment.

Uncovering pre-cytokinetic block in cancer cells under shear stress using a disturbed flow-generating device

During metastasis, cancer cells navigate through harsh conditions, including various mechanical forces in the bloodstream, highlighting the need to understand the impact of mechanical and shear stresses on cancer cells. To overcome the current methodological limitations of such research, here we present a new device that replicates similar conditions by applying shear stress on cultured cells. The device provides a less complex, easily accessible alternative to traditional fluidics while generating fluid shear stress values comparable to those in human veins and capillaries. The device allows analyses of large cell numbers in standard cell culture flasks and incubators. Using this device to explore the shear stress-induced responses of various human cell lines, we discovered a previously unknown, reversible pre-cytokinetic block occurring in cells that lose anchorage during mitosis and are kept under constant shear stress. Notably, some cancer cell lines appear to bypass this unorthodox cell-cycle block, suggesting its role as a safety checkpoint to restrict the proliferation of cancer cells in the bloodstream and their overall spreading potential. These findings provide new insights into the diverse responses of normal and cancer cells to shear stress and highlight the potential of our technology for research on circulating tumor cells and metastatic spread.

Molecular mechanisms in liver repair and regeneration: from physiology to therapeutics

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

Hepatic Arterial Flow-Induced Portal Tract Fibrosis in Portal Hypertension: The Role of VCAM-1 and Osteopontin-Expressing Macrophages

Background

The liver undergoes significant hemodynamic changes during surgery, transplantation, or cirrhosis with portal hypertension(PH). The hepatic artery buffer response(HABR), which compensates for reduced portal venous flow by increasing hepatic artery(HA) flow, is hypothesized to induce pathological portal tract remodeling. This study investigates the molecular mechanisms underlying this process.

Methods

PH was induced in Sprague-Dawley rats via partial portal vein ligation(PPVL). Structural evaluation(microCT), immune cell profiling, hemodynamic measurements, and transcriptomic analysis in macrophages(Mϕ) from sham or PPVL rats were conducted.

Results

MicroCT revealed decreased portal vein flow and increased HA flow correlated with portal pressure(r=0.799, p<0.01). A 2-fold increase in portal tract fibrosis(p<0.001) was observed with increased α-SMA+ myofibroblasts in PPVL rats. CD68+ Mϕ peaked at 10 days post-PPVL, and their depletion significantly reduced fibrosis(p<0.001), indicating critical roles of Mϕ in portal tract remodeling. VCAM-1 was elevated in HA endothelium and portal fibroblasts (PFs); VCAM-1 neutralization reduced collagen accumulation(p<0.05), CD68+ Mϕ(46.3%, p<0.01), and CD3+ T cells(18%, p<0.05). Mϕ-conditioned medium increased VCAM-1 in PFs(8-fold, p<0.001) and enhanced PF migration, while VCAM-1 knockdown reduced this effect (p<0.01). Single-cell RNA sequencing data(GSE171904) and RNA-FISH revealed increased interactions between osteopontin (Spp1)+ Mϕ and PFs, with Spp1+ Mϕ driving fibrosis. Spp1 knockdown in Mϕ co-culture reduced PF fibrogenic markers, while recombinant Spp1 upregulated Col1a1, Fn1, and Acta2 expression in PFs.

Conclusion

Increased VCAM-1 in arterial endothelial cells and PFs facilitates the recruitment of Spp1+ Mϕ, which drive HA flow-mediated vascular remodeling and portal tract fibrosis. These findings highlight arterial flow-induced fibrosis as a key mechanism in PH, potentially contributing to disease progression and decompensation.

Synopsis

Liver hemodynamic changes in portal hypertension drive extracellular matrix accumulation and portal tract remodeling via Spp1+ macrophages. This study highlights how altered blood flow induces fibrosis, and its potential role in decompensation, and identifies therapeutic targets for advanced liver disease.

The LINC complex in blood vessels: from physiology to pathological implications in arterioles

The LINC (linker of nucleoskeleton and cytoskeleton) complex is a critical component of the cellular architecture that bridges the nucleoskeleton and cytoskeleton and mediates mechanotransduction to and from the nucleus. Though it plays important roles in all blood vessels, it is in arterioles that this complex plays a pivotal role in maintaining endothelial cell integrity, regulating vascular tone, forming new microvessels and modulating responses to mechanical and biochemical stimuli. It is also important in vascular smooth muscle cells and fibroblasts, where it possibly plays a role in the contractile to secretory phenotypic transformation during atherosclerosis and vascular ageing, and in fibroblasts' migration and inflammatory responses in the adventitia. Physiologically, the LINC complex contributes to the stability of arteriolar structure, adaptations to changes in blood flow and injury repair mechanisms. Pathologically, dysregulation or mutations in LINC complex components can lead to compromised endothelial function, vascular remodelling and exacerbation of cardiovascular diseases such as atherosclerosis (arteriolosclerosis). This review summarizes our current understanding of the roles of the LINC complex in cells from arterioles, highlighting its most important physiological functions, exploring its implications for vascular pathology and emphasizing some of its functional characteristics in endothelial cells. By elucidating the LINC complex's role in health and disease, we aim to provide insights that could improve future therapeutic strategies targeting LINC complex-related vascular disorders.

Hemodynamic disturbance and mTORC1 activation: Unveiling the biomechanical pathogenesis of thoracic aortic aneurysms in Marfan syndrome

Thoracic aortic aneurysm (TAA) significantly endangers the lives of individuals with Marfan syndrome (MFS), yet the intricacies of their biomechanical origins remain elusive. Our investigation delves into the pivotal role of hemodynamic disturbance in the pathogenesis of TAA, with a particular emphasis on the mechanistic contributions of the mammalian target of rapamycin (mTOR) signaling cascade. We uncovered that activation of the mTOR complex 1 (mTORC1) within smooth muscle cells, instigated by the oscillatory wall shear stress (OSS) that stems from disturbed flow (DF), is a catalyst for TAA progression. This revelation was corroborated through both an MFS mouse model (Fbn1 +/C1039G) and clinical MFS specimens. Crucially, our research demonstrates a direct linkage between the activation of the mTORC1 pathway and the intensity in OSS. Therapeutic administration of rapamycin suppresses mTORC1 activity, leading to the attenuation of aberrant SMC behavior, reduced inflammatory infiltration, and restoration of extracellular matrix integrity-collectively decelerating TAA advancement in our mouse model. These insights posit the mTORC1 axis as a strategic target for intervention, offering a novel approach to manage TAAs in MFS and potentially pave insights for current treatment paradigms.

Transcriptional profile of the rat cardiovascular system at single-cell resolution

We sought to characterize cellular composition across the cardiovascular system of the healthy Wistar rat, an important model in preclinical cardiovascular research. We performed single-nucleus RNA sequencing (snRNA-seq) in 78 samples in 10 distinct regions, including the four chambers of the heart, ventricular septum, sinoatrial node, atrioventricular node, aorta, pulmonary artery, and pulmonary veins, which produced 505,835 nuclei. We identified 26 distinct cell types and additional subtypes, with different cellular composition across cardiac regions and tissue-specific transcription for each cell type. Several cell subtypes were region specific, including a subtype of vascular smooth muscle cells enriched in the large vasculature. We observed tissue-enriched cellular communication networks, including heightened Nppa-Npr1/2/3 signaling in the sinoatrial node. The existence of tissue-restricted cell types suggests regional regulation of cardiovascular physiology. Our detailed transcriptional characterization of each cell type offers the potential to identify novel therapeutic targets and improve preclinical models of cardiovascular disease.

Sodium-Glucose-Cotransporter-2 Inhibitor Therapy and Intermitted Fasting in Cardiorenal Syndrome: The Role of Glucose-Mediated Oxidative Stress

Cardiorenal syndrome (CRS) is a complex clinical disorder characterized by the interplay between heart and kidney dysfunction. This condition is exacerbated by comorbidities such as diabetes mellitus, which contribute to glucose-mediated oxidative stress, further complicating the management of CRS. The management of CRS has evolved with the discovery of sodium-glucose-cotransporter-2 (SGLT2) inhibitors, which have been established as effective agents in reducing hyperglycemia and demonstrated cardiorenal protective effects. Concurrently, intermittent fasting has gained attention as an intervention without pharmacological treatment for its metabolic benefits, including improved glucose metabolism and insulin regulation and sensitivity, both with a potential reduction in oxidative stress. This review provides a summary of current findings on the roles of SGLT2 inhibitors and intermittent fasting in managing CRS, with a particular focus on glucose-mediated oxidative stress. We evaluate the mechanisms by which these interventions exert their effects, identify gaps in current research, and offer recommendations for future studies. While both SGLT2 inhibitors and intermittent fasting demonstrate potential in managing CRS, more research is needed to elucidate their long-term efficacy, safety, and potential synergistic effects.

Design, fabrication, and application of bioengineering vascular networks based on microfluidic strategies

Vascularization is a critical component of tissue engineering research and is essential for enhancing the success rate of tissue construction and function. Over the past decade, researchers have explored various methods to construct in vitro vascular networks, including 3D printing, cell sphere technology, and microfluidics. Microfluidic technology has garnered significant attention due to its notable advantages in precision, controllability, flexibility, and applicability. It can be primarily classified into two modes: (i) the pre-designed mode, which involves creating vascular networks by pre-designing vascular channels and seeding endothelial cells, encompassing microfluidic chips and microfluidic spinning technologies; and (ii) the self-assembly mode, where cell spheres are fabricated using microfluidic technology and subsequently self-assemble into vascular networks. In this review, we first provide a brief overview of the normal physiological and pathological characteristics of vascular networks, followed by a discussion of the factors to be considered in designing in vitro vascular networks, and conclude with an examination of the classification of technologies for the preparation of microfluidic vascular networks and recent advancements. It is anticipated that in vitro vascular network models will soon be successfully applied in regenerative medicine and drug development.

Wall shear stress modulates metabolic pathways in endothelial cells

INTRODUCTION

Hemodynamic forces play a crucial role in modulating endothelial cell (EC) behavior, significantly influencing blood vessel responses. While traditional in vitro studies often explore ECs under static conditions, ECs are exposed to various hemodynamic forces in vivo. This study investigates how wall shear stress (WSS) influences EC metabolism, focusing on the interplay between WSS and key metabolic pathways.

OBJECTIVES

The aim of this study is to examine the effects of WSS on EC metabolism, specifically evaluating its impact on central carbon metabolism and glycolysis using transcriptomics and tracer metabolomics approaches.

METHODS

ECs were exposed to WSS, and transcriptomic analysis was performed to assess gene expression changes related to metabolic pathways. Tracer metabolomics was used to track metabolic fluxes, focusing on glutamine and glycolytic metabolism. Additionally, chemical inhibition of glutamate dehydrogenase was conducted to evaluate its role in EC fitness under WSS.

RESULTS

Transcriptomic data revealed upregulation of glutamine and glutamate pathways, alongside downregulation of glycolytic activity in ECs exposed to WSS. Tracer metabolomics confirmed that WSS promotes glutamine anaplerosis into the Krebs cycle, while decreasing glycolytic metabolism. Suppression of glutamate dehydrogenase impaired EC fitness under WSS conditions.

CONCLUSION

Our findings illuminate that ECs subjected to WSS exhibit a preference for glutamine as a key nutrient source for central carbon metabolism pathways, indicating diminished reliance on glycolysis. This study elucidates the nutritional predilections and regulatory mechanisms governing EC metabolism under WSS in vitro, underscoring the pivotal role of physical stimuli in shaping EC metabolic responses.

Repeated Ischemic Stroke due to in situ Thrombus at the Middle Cerebral Artery in a Patient with Essential Thrombocythemia

Essential thrombocythemia (ET) is a myeloproliferative neoplasm that is a rare cause of ischemic stroke. We herein report a 70-year-old man with JAK2 V617F mutation-positive ET who experienced ischemic stroke twice in 1 month due to transient stenosis. In both events, transient stenosis formed at the same curvature of the right middle cerebral artery, and the thrombus disappeared with the initiation of antiplatelet agents. The formation of in situ thrombus at the curvature of the intracranial vessels may be a unique characteristic of JAK2 V617F mutation-positive ET patients.

Increased serum galectin-3 level is associated with endothelial dysfunction and cardiovascular events in patients with hypertension

Background

Endothelial dysfunction can lead to various harmful cardiovascular complications. The importance of galectin-3 (Gal-3) has been proposed in some cardiac diseases related to chronic inflammation. However, its role in hypertension-induced endothelial dysfunction remains unclear.

Methods

We enrolled 120 patients with hypertension, assessed their baseline characteristics, and monitored their 7-year cardiovascular outcomes. We performed an enzyme-linked immunosorbent assay to measure serum Gal-3 levels. The vascular reactivity index (VRI) was examined by digital thermal monitoring. Patients with VRI <1.0, 1.0 to <2.0, and ≥2.0 were defined as having poor, intermediate, and good vascular reactivity, respectively.

Results

Among the recruited patients, 12 had poor vascular reactivity, 57 had intermediate vascular reactivity, and 51 had good vascular reactivity. Older age, higher total cholesterol levels, higher low-density lipoprotein cholesterol levels, lower estimated glomerular filtration rate, and higher Gal-3 levels were associated with poor endothelial dysfunction. Multivariate linear regression analysis showed that age and Gal-3 levels were correlated with VRI. During the 7-year follow-up period, patients with higher Gal-3 levels had more cardiovascular events.

Conclusions

Higher Gal-3 levels are associated with endothelial dysfunction and unfavorable cardiovascular outcomes in patients with hypertension, suggesting its potential role in the hypertension-induced endothelial dysfunction.

The effects of enhanced external counter-pulsation on post-acute sequelae of COVID-19: A narrative review

Some of the millions of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have developed new sequelae after recovering from the initial disease, termed post-acute sequelae of coronavirus disease 2019 (PASC). One symptom is anxiety, which is likely due to three etiologies: brain structural changes, neuroendocrine disruption, and neurotransmitter alterations. This review provides an overview of the current literature on the pathophysiological pathways linking coronavirus disease 2019 to anxiety, as well as the possible mechanisms of action in which an increasingly scrutinized treatment method, enhanced external counter-pulsation (EECP), is able to alleviate anxiety. SARS-CoV-2 triggers increased inflammatory cytokine production, as well as oxidative stress; these processes contribute to the aforementioned three etiologies. The potential treatment approach of EECP, involving sequenced inflation and deflation of specifically-placed airbags, has become of increasing interest, as it has been found to alleviate PASC-associated anxiety by improving patient cardiovascular function. These functional improvements were achieved by EECP stimulating anti-inflammatory and pro-angiogenic processes, as well as improving endothelial cell function and coronary blood flow, partially via counteracting against the negative effects of SARS-CoV-2 infection on the renin-angiotensin-aldosterone system. Therefore, EECP could promote both psychosomatic and cardiac rehabilitation. Further research, though, is still needed to fully determine its benefits and mechanism of action.

The interdependent hemodynamic influence between abdominal aortic aneurysm and renal artery stenosis

Cardiovascular diseases remain a leading cause of morbidity and mortality worldwide with abdominal aortic aneurysm (AAA) and renal artery stenosis (RAS) standing out as significant contributors to the vascular pathology spectrum. While these conditions have traditionally been approached as distinct entities, emerging evidence suggests a compelling interdependent relationship between AAA and RAS, challenging the conventional siloed understanding. The confluence of AAA and RAS represents a complex interplay within the cardiovascular system, one that is often overlooked in clinical practice and research. Here, we reveal a bidirectional consequential impact between these two diseases. The location of the AAA sac was investigated for its specific influence on the risk of RAS development. Although studies have shown a higher coincidence between the suprarenal AAA and RAS, our findings demonstrated that the presence of a suprarenal AAA correlated with the lowest risk of RAS development among the three investigated AAA locations. Notably, we also highlighted that the pre-existence of stenosis in the renal artery poses an elevated risk for the formation of suprarenal AAA, assessed by an increased wall shear stress gradient on the aortic wall. Our findings prompt a paradigm shift in the understanding and treatment of AAA and RAS in clinical practice.

Flow-Dependent Modulation of Endothelial Ca2+ Dynamics by Small Conductance Ca2+-Activated K+ Channels in Mouse Carotid Arteries

BACKGROUND

Small conductance Ca2+ activated K+ channels (KCa2.3) are important regulators of vascular function. They provide Ca2+-dependent hyperpolarization of the endothelial membrane potential, promoting agonist-induced vasodilation. Another important mechanism of influence may occur through positive feedback regulation of endothelial Ca2+ signals, likely via amplification of influx through membrane cation channels. KCa2.3 channels have recently been implicated in flow-mediated dilation of the arterial vasculature and may contribute to the crucial homeostatic role of shear stress in preventing vascular wall remodeling and progressive vascular disease (i.e., atherosclerosis). The impact of KCa2.3 channels on endothelial Ca2+ signaling under physiologically relevant shear stress conditions remains unknown.

METHODS

In the current study, we employ mice expressing an endothelium-specific Ca2+ fluorophore (cdh5-GCaMP8) to characterize the KCa2.3 channel influence on the dynamic Ca2+ signaling profile along the arterial endothelium in the presence and absence of shear-stress.

RESULTS

Our data indicate KCa2.3 channels have a minimal influence on basal Ca2+ signaling in the carotid artery endothelium in the absence of flow, but they contribute substantially to amplification of Ca2+ dynamics in the presence of flow and their influence can be augmented through exogenous positive modulation.

CONCLUSIONS

The findings suggest a pivotal role for KCa2.3 channels in adjusting the profile of homeostatic dynamic Ca2+ signals along the arterial intima under flow.

SMOC2, OGN, FCN3, and SERPINA3 could be biomarkers for the evaluation of acute decompensated heart failure caused by venous congestion

Background

Venous congestion (VC) sets in weeks before visible clinical decompensation, progressively increasing cardiac strain and leading to acute heart failure (HF) decompensation. Currently, the field lacks a universally acknowledged gold standard and early detection methods for VC.

Methods

Using data from the GEO database, we identified VC's impact on HF through key genes using Limma and STRING databases. The potential mechanisms of HF exacerbation were explored via GO and KEGG enrichment analyses. Diagnostic genes for acute decompensated HF were discovered using LASSO, RF, and SVM-REF machine learning algorithms, complemented by single-gene GSEA analysis. A nomogram tool was developed for the diagnostic model's evaluation and application, with validation conducted on external datasets.

Results

Our findings reveal that VC influences 37 genes impacting HF via 8 genes, primarily affecting oxygen transport, binding, and extracellular matrix stability. Four diagnostic genes for HF's pre-decompensation phase were identified: SMOC2, OGN, FCN3, and SERPINA3. These genes showed high diagnostic potential, with AUCs for each gene exceeding 0.9 and a genomic AUC of 0.942.

Conclusions

Our study identifies four critical diagnostic genes for HF's pre-decompensated phase using bioinformatics and machine learning, shedding light on the molecular mechanisms through which VC worsens HF. It offers a novel approach for clinical evaluation of acute decompensated HF patient congestion status, presenting fresh insights into its pathogenesis, diagnosis, and treatment.

The impact of different degrees of stenosis on platelet deposition in the left anterior descending branch of the coronary artery

BACKGROUND AND OBJECTIVE

This study aimed to investigate the impact of different stenotic degrees on platelet deposition in the left anterior descending branch of the coronary artery.

METHODS

The idealized model of coronary artery stenosis of 30 %, 40 %, 50 %, 60 %, 70 % and four patient-specific models of 22.17 %, 34.88 %, 51.23 % and 62.96 % were established. A discrete phase model was used to calculate the deposition of platelet particles in blood.

RESULTS

(1) As the stenotic degree increased from 30 % to 70 %, the maximum deposition rates were 4.23e-2 kg/(m2 ·s), 3.47e-2 kg/(m2 ·s), 0.14 kg/(m2 ·s), 0.15 kg/(m2 ·s), and 0.38 kg/(m2 ·s), respectively. (2) The greater the stenotic degree, the more points of platelet deposition. (3) Platelets were mainly deposited at the proximal segment of mild stenosis. When the stenotic degree exceeded 50 %, the deposition position moved to the distal segment of the stenosis. (4) The results in the real coronary artery models were similar to those in the idealized model.

CONCLUSION

The study suggests that the location and number of platelet deposition are related to the degree of stenosis. Moderate to severe stenosis is more likely to spread downstream.

Force-sensing protein expression in response to cardiovascular mechanotransduction

Force-sensing biophysical cues in microenvironment, including extracellular matrix performances, stretch-mediated mechanics, shear stress and flow-induced hemodynamics, have a significant influence in regulating vascular morphogenesis and cardiac remodeling by mechanotransduction. Once cells perceive these extracellular mechanical stimuli, Piezo activation promotes calcium influx by forming integrin-adhesion-coupling receptors. This induces robust contractility of cytoskeleton structures to further transmit biomechanical alternations into nuclei by regulating Hippo-Yes associated protein (YAP) signaling pathway between cytoplasmic and nuclear translocation. Although biomechanical stimuli are widely studied in cardiovascular diseases, the expression of force-sensing proteins in response to cardiovascular mechanotransduction has not been systematically concluded. Therefore, this review will summarize the force-sensing Piezo, cytoskeleton and YAP proteins to mediate extracellular mechanics, and also give the prominent emphasis on intrinsic connection of these mechanical proteins and cardiovascular mechanotransduction. Extensive insights into cardiovascular mechanics may provide some new strategies for cardiovascular clinical therapy.

Prognostic value of morphology and hemodynamics in moyamoya disease for long-term outcomes and disease progression

To explore the relationship between morphological and hemodynamic parameters, baseline characteristics, and long-term outcomes in patients with moyamoya disease (MMD) using a computational fluid dynamics model. We retrospectively reviewed 129 patients at Beijing Tiantan hospital between July 2020 and December 2021. Perioperative clinical variables and Suzuki stage were recorded. Logistic regression analysis was employed to identify the risk factors for unfavorable long-term outcomes. The association between morphological, CT perfusion parameters, hemodynamic parameters and the Suzuki stage, clinical variables of MMD was also analyzed. Patients with high relative Wall Shear Stress (rWSS) were older and had more cases with higher Suzuki stage and worse follow-up mRS scores (p < 0.05). High rWSS at the terminal ICA and diabetes mellitus were identified as independent predictors of unfavorable long-term outcomes [OR = 3.039(1.191-7.754), p = 0.020; OR = 3.164(1.141-8.723), p = 0.027, respectively]. ROC analysis demonstrated that predictive models incorporating rWSS improved AUC values, with the highest AUC in Model 2 (AUC = 0.889). High rWSS was significantly associated with future TIA and stroke events (p = 0.032). We speculated that high rWSS and diabetes mellitus were independent risk factors for unfavorable long-term outcomes in patients with MMD. rWSS and morphological parameters are crucial for predicting MMD progression and understanding its pathogenesis.

Engineered Biomimetic Nanoparticles-Mediated Targeting Delivery of Allicin Against Myocardial Ischemia-Reperfusion Injury by Inhibiting Ferroptosis

Background

Cardiac microvascular damage is substantially related with the onset of myocardial ischaemia-reperfusion (IR) injury. Reportedly, allicin (AL) effectively protects the cardiac microvascular system from IR injury. However, the unsatisfactory therapeutic efficacy of current drugs and insufficient drug delivery to the damaged heart are major concerns. Here, inspired by the natural interaction between neutrophils and inflamed cardiac microvascular endothelial cells (CMECs), a neutrophil membrane-camouflaged nanoparticle for non-invasive active-targeting therapy for IR injury by improving drug delivery to the injured heart is constructed.

Methods

In this study, we engineered mesoporous silica nanoparticles (MSNs) coated with a neutrophil membrane to act as a drug delivery system, encapsulating AL. The potential of the nanoparticles (named AL@MSNs@NM) for specific targeting of infarcted myocardium was assessed using small animal vivo imaging system. The cardiac function of AL@MSNs@NM after treatment was evaluated by Animal Ultrasound Imaging system, HE staining, and Laser Speckle Imaging System. The therapeutic mechanism was analyzed by ELISA kits, immunofluorescence, and PCR.

Results

We discovered that AL@MSNs@NM significantly improves cardiac function index, reduced infarct size and fibrosis, increased vascular perfusion in ischemic areas, and also promoted the function of CMECs, including migration, tube formation, shear stress adaptation, and nitric oxide production. Further research revealed that AL@MSNs@NM have cardio-protective functions in IR rats by inhibiting CMEC ferroptosis and increasing platelet endothelial cell adhesion molecule-1 (PECAM-1) expression.

Conclusion

Our results indicated that AL@MSNs@NM significantly reversed CMEC ferroptosis and increased PECAM-1 expression, enhanced cardiac function, and reduced myocardial infarction size. Therefore, this strategy demonstrates that engineered biomimetic nanotechnology effectively delivers AL for targeted therapy of myocardial infarction.

High Blood Pressure and Impaired Brain Health: Investigating the Neuroprotective Potential of Magnesium

High blood pressure (BP) is a significant contributor to the disease burden globally and is emerging as an important cause of morbidity and mortality in the young as well as the old. The well-established impact of high BP on neurodegeneration, cognitive impairment, and dementia is widely acknowledged. However, the influence of BP across its full range remains unclear. This review aims to explore in more detail the effects of BP levels on neurodegeneration, cognitive function, and dementia. Moreover, given the pressing need to identify strategies to reduce BP levels, particular attention is placed on reviewing the role of magnesium (Mg) in ageing and its capacity to lower BP levels, and therefore potentially promote brain health. Overall, the review aims to provide a comprehensive synthesis of the evidence linking BP, Mg and brain health. It is hoped that these insights will inform the development of cost-effective and scalable interventions to protect brain health in the ageing population.

Identification of molecular targets of Hypericum perforatum in blood for major depressive disorder: a machine-learning pharmacological study

BACKGROUND

Major depressive disorder (MDD) is one of the most common psychiatric disorders worldwide. Hypericum perforatum (HP) is a traditional herb that has been shown to have antidepressant effects, but its mechanism is unclear. This study aims to identify the molecular targets of HP for the treatment of MDD.

METHODS

We performed differential analysis and weighted gene co-expression network analysis (WGCNA) with blood mRNA expression cohort of MDD and healthy control to identify DEGs and significant module genes (gene list 1). Three databases, CTD, DisGeNET, and GeneCards, were used to retrieve MDD-related gene intersections to obtain MDD-predicted targets (gene list 2). The validated targets were retrieved from the TCMSP database (gene list 3). Based on these three gene lists, 13 key pathways were identified. The PPI network was constructed by extracting the intersection of genes and HP-validated targets on all key pathways. Key therapeutic targets were obtained using MCODE and machine learning (LASSO, SVM-RFE). Clinical diagnostic assessments (Nomogram, Correlation, Intergroup expression), and gene set enrichment analysis (GSEA) were performed for the key targets. In addition, immune cell analysis was performed on the blood mRNA expression cohort of MDD to explore the association between the key targets and immune cells. Finally, molecular docking prediction was performed for the targets of HP active ingredients on MDD.

RESULTS

Differential expression analysis and WGCNA module analysis yielded 933 potential targets for MDD. Three disease databases were intersected with 982 MDD-predicted targets. The TCMSP retrieved 275 valid targets for HP. Separate enrichment analysis intersected 13 key pathways. Five key targets (AKT1, MAPK1, MYC, EGF, HSP90AA1) were finally screened based on all enriched genes and HP valid targets. Combined with the signaling pathway and immune cell analysis suggested the effect of peripheral immunity on MDD and the important role of neutrophils in immune inflammation. Finally, the binding of HP active ingredients (quercetin, kaempferol, and luteolin) and all 5 key targets were predicted based on molecular docking.

CONCLUSIONS

The active constituents of Hypericum perforatum can act on MDD and key targets and pathways of this action were identified.

A nanoporous hydrogel-based model to study chemokine gradient-driven angiogenesis under luminal flow

The growth of new blood vessels through angiogenesis is a highly coordinated process, which is initiated by chemokine gradients that activate endothelial cells within a perfused parent vessel to sprout into the surrounding 3D tissue matrix. While both biochemical signals from pro-angiogenic factors, as well as mechanical cues originating from luminal fluid flow that exerts shear stress on the vessel wall, have individually been identified as major regulators of endothelial cell sprouting, it remains unclear whether and how both types of cues synergize. To fill this knowledge gap, here, we created a 3D biomimetic model of chemokine gradient-driven angiogenic sprouting, in which a micromolded tube inside a hydrogel matrix is seeded with endothelial cells and connected to a perfusion system to control fluid flow rates and resulting shear forces on the vessel wall. To allow for the formation of chemokine gradients despite the presence of luminal flow, a nanoporous synthetic hydrogel that supports angiogenesis but limits the interstitial flow proved crucial. Using this system, we find that luminal flow and resulting shear stress is a major regulator of the speed and morphogenesis of angiogenic sprouting, whose action is mediated through changes in vascular permeability.

Exploring the relationship between hemodynamics and the immune microenvironment in carotid atherosclerosis: Insights from CFD and CyTOF technologies

Carotid atherosclerosis is a major cause of stroke. Hemodynamic forces, such as shear stress and oscillatory shear, play an important role in the initiation and progression of atherosclerosis. The alteration of the immune microenvironment is the fundamental pathological mechanism by which diverse external environmental factors impact the formation and progression of plaques. However, Current research on the relationship between hemodynamics and immunity in atherosclerosis still lack of comprehensive understanding. In this study, we combined computational fluid dynamics (CFD) and Mass cytometry (CyTOF) technologies to explore the changes in the immune microenvironment within plaques under different hemodynamic conditions. Our results indicated that neutrophils were enriched in adverse flow environments. M2-like CD163+CD86+ macrophages were predominantly enriched in high WSS and low OSI environments, while CD163-CD14+ macrophages were enriched in low WSS and high OSI environments. Functional analysis further revealed T cell pro-inflammatory activation and dysregulation in modulation, along with an imbalance in M1-like/M2-like macrophages, suggesting their potential involvement in the progression of atherosclerotic lesions mediated by adverse flow patterns. Our study elucidated the potential mechanisms by which hemodynamics regulated the immune microenvironment within plaques, providing intervention targets for future precision therapies.

An Endothelial Cell Is Not Simply an Endothelial Cell

Endothelial cells (ECs) are a multifaceted component of the vascular system with roles in immunity, maintaining tissue fluid balance, and vascular tone. Dysregulation or dysfunction of ECs can have far-reaching implications, leading pathologies ranging from cardiovascular diseases, such as hypertension and atherosclerosis, ischemia, chronic kidney disease, blood-brain barrier integrity, dementia, and tumor metastasis. Recent advancements in regenerative medicine have highlighted the potential of stem cell-derived ECs, particularly from induced pluripotent stem cells, to treat ischemic tissues, as well as models of vascular integrity. This review summarizes what is known in the generation of ECs with an emphasis on tissue-specific ECs and EC subphenotypes important in the development of targeted cell-based therapies for patient treatment.

Mechanical strategies to promote vascularization for tissue engineering and regenerative medicine

Vascularization is a major challenge in the field of tissue engineering and regenerative medicine. Mechanical factors have been demonstrated to play a fundamental role in vasculogenesis and angiogenesis and can affect the architecture of the generated vascular network. Through the regulation of mechanical factors in engineered tissues, various mechanical strategies can be used to optimize the preformed vascular network and promote its rapid integration with host vessels. Optimization of the mechanical properties of scaffolds, including controlling scaffold stiffness, increasing surface roughness and anisotropic structure, and designing interconnected, hierarchical pore structures, is beneficial for the in vitro formation of vascular networks and the ingrowth of host blood vessels. The incorporation of hollow channels into scaffolds promotes the formation of patterned vascular networks. Dynamic stretching and perfusion can facilitate the formation and maturation of preformed vascular networks in vitro. Several indirect mechanical strategies provide sustained mechanical stimulation to engineered tissues in vivo, which further promotes the vascularization of implants within the body. Additionally, stiffness gradients, anisotropic substrates and hollow channels in scaffolds, as well as external cyclic stretch, boundary constraints and dynamic flow culture, can effectively regulate the alignment of vascular networks, thereby promoting better integration of prevascularized engineered tissues with host blood vessels. This review summarizes the influence and contribution of both scaffold-based and external stimulus-based mechanical strategies for vascularization in tissue engineering and elucidates the underlying mechanisms involved.

Low or oscillatory shear stress and endothelial permeability in atherosclerosis

Endothelial shear stress is a tangential stress derived from the friction of the flowing blood on the endothelial surface of the arterial wall and is expressed in units of force/unit area (dyne/cm2). Branches and bends of arteries are exposed to complex blood flow patterns that generate low or oscillatory endothelial shear stress, which impairs glycocalyx integrity, cytoskeleton arrangement and endothelial junctions (adherens junctions, tight junctions, gap junctions), thus increasing endothelial permeability. The lipoproteins and inflammatory cells penetrating intima due to the increased endothelial permeability characterizes the pathological changes in early stage of atherosclerosis. Endothelial cells are critical sensors of shear stress, however, the mechanisms by which the complex shear stress regulate endothelial permeability in atherosclerosis remain unclear. In this review, we focus on the molecular mechanisms of the endothelial permeability induced by low or oscillatory shear stress, which will shed a novel sight in early stage of atherosclerosis.

Acute effects of static stretching exercise-induced decrease in arterial stiffness on maximal aerobic capacity

BACKGROUND

We recently have reported that individual day-to-day arterial stiffness variations are associated with maximal aerobic capacity. However, the evidence of this phenomenon was not provided sufficiently. The present study aimed to examine whether a decrease in arterial stiffness through static stretching exercise could enhance maximal aerobic capacity.

METHODS

Twelve healthy young men (age 22±2 years, mean and standard deviation) participated in this study and underwent two separate sessions in a randomized controlled crossover design: a single session of a whole-body static stretching exercise protocol that involved the trunk, upper limb, and lower limb (stretch condition), and sedentary control where they rested in the exercise room. Brachial-ankle pulse wave velocity (baPWV) was measured as an index of systemic arterial stiffness before, immediately after and at 30 min after both conditions. Maximal oxygen uptake (V̇O2max) was assessed using a graded power test on an electronically braked cycle ergometer after these measurements.

RESULTS

As we expected, there was a significant decrease in the baPWV at 30 min after the stretch trial compared to baseline values (P=0.01). The baPWV in the stretch condition was lower than that of the control condition, while V̇O2max in the stretch condition was higher than that of the control condition (P=0.03).

CONCLUSIONS

Based on these findings, it can be inferred that an acute reduction in arterial stiffness may contribute to change in maximal aerobic capacity.

Oxidative stress and vascular dysfunction: Potential therapeutic targets and therapies in peripheral artery disease

Peripheral artery disease (PAD) is the manifestation of atherosclerosis characterized by the accumulation of plaques in the arteries of the lower limbs. Interestingly, growing evidence suggests that the pathology of PAD is multifaceted and encompasses both vascular and skeletal muscle dysfunctions, which contributes to blunted physical capabilities and diminished quality of life. Importantly, it has been suggested that many of these pathological impairments may stem from blunted reduction-oxidation (redox) handling. Of note, in those with PAD, excessive production of reactive oxygen species (ROS) outweighs antioxidant capabilities resulting in oxidative damage, which may have systemic consequences. It has been suggested that antioxidant supplementation may be able to assist in handling ROS. However, the activation of various ROS production sites makes it difficult to determine the efficacy of these antioxidant supplements. Therefore, this review focuses on the common cellular mechanisms that facilitate ROS production and discusses how excessive ROS may impair vascular and skeletal muscle function in PAD. Furthermore, we provide insight for current and potential antioxidant therapies, specifically highlighting activation of the Kelch-like ECH-associated protein 1 (Keap1) - Nuclear Factor Erythroid 2-related factor 2 (Nrf2) pathway as a potential pharmacological therapy to combat ROS accumulation and aid in vascular function, and physical performance in patients with PAD. Altogether, this review provides a better understanding of excessive ROS in the pathophysiology of PAD and enhances our perception of potential therapeutic targets that may improve vascular function, skeletal muscle function, walking capacity, and quality of life in patients with PAD.

Tracer-based metabolomics for profiling nitric oxide metabolites in a 3D microvessels-on-chip model

Endothelial dysfunction, prevalent in cardiovascular diseases (CVDs) and linked to conditions like diabetes, hypertension, obesity, renal failure, or hypercholesterolemia, is characterized by diminished nitric oxide (NO) bioavailability-a key signaling molecule for vascular homeostasis. Current two-dimensional (2D) in vitro studies on NO synthesis by endothelial cells (ECs) lack the crucial laminar shear stress, a vital factor in modulating the NO-generating enzyme, endothelial nitric oxide synthase (eNOS), under physiological conditions. Here we developed a tracer-based metabolomics approach to measure NO-specific metabolites with mass spectrometry (MS) and show the impact of fluid flow on metabolic parameters associated with NO synthesis using 2D and 3D platforms. Specifically, we tracked the conversion of stable-isotope labeled NO substrate L-Arginine to L-Citrulline and L-Ornithine to determine eNOS activity. We demonstrated clear responses in human coronary artery endothelial cells (HCAECs) cultured with 13C6, 15N4-L-Arginine, and treated with eNOS stimulator, eNOS inhibitor, and arginase inhibitor. Analysis of downstream metabolites, 13C6, 15N3 L-Citrulline and 13C5, 15N2 L-Ornithine, revealed distinct outcomes. Additionally, we evaluated the NO metabolic status in static 2D culture and 3D microvessel models with bidirectional and unidirectional fluid flow. Our 3D model exhibited significant effects, particularly in microvessels exposed to the eNOS stimulator, as indicated by the 13C6, 15N3 L-Citrulline/13C5, 15N2 L-Ornithine ratio, compared to the 2D culture. The obtained results indicate that the 2D static culture mimics an endothelial dysfunction status, while the 3D model with a unidirectional fluid flow provides a more representative physiological environment that provides a better model to study endothelial dysfunction.

Vascular endothelial effects of dibutyl phthalate: In vitro and in vivo evidence

Dibutyl phthalate (DBP) is widely used in many consumer and personal care products. Here, we report vascular endothelial response to DBP in three different exposure scenarios: after short-term exposure (24 h) of human endothelial cells (ECs) EA.hy926 to 10-6, 10-5, and 10-4 M DBP, long-term exposure (12 weeks) of EA.hy926 cells to 10-9, 10-8, and 10-7 M DBP, and exposure of rats (28 and 90 days) to 100, 500, and 5000 mg DBP/kg food. We examined different vascular functions such as migration of ECs, adhesion of ECs to the extracellular matrix, tube formation, the morphology of rat aorta, as well as several signaling pathways involved in controlling endothelial function. Short-term in vitro exposure to DBP increased migration of ECs through G protein-coupled estrogen receptor, extracellular signal-regulated kinase 1/2, and nitric oxide (NO) signaling and decreased adhesion to gelatin. Long-term in vitro exposure to DBP transiently increased EC migration and had a bidirectional effect on EC adhesion to gelatin and tube formation. These effects were accompanied by a sustained increase in NO production and endothelial NO synthase (eNOS) and Akt activity. In vivo, exposure to DBP for 90 days decreased the aortic wall-to-lumen ratio and increased eNOS and Akt phosphorylation in ECs of rat aorta. This comparative investigation has shown that exposure to DBP may affect vascular function by altering EC migration, adhesion to gelatin, and tube formation after short- and long-term in vitro exposure and by decreasing the aortic wall-to-lumen ratio in vivo. The eNOS-NO and Akt signaling could be important in mediating the effects of DBP in long-term exposure scenarios.

Potential role of endothelial progenitor cells in the pathogenesis and treatment of cerebral aneurysm

Cerebral aneurysm (CA) is a significant health concern that results from pathological dilations of blood vessels in the brain and can lead to severe and potentially life-threatening conditions. While the pathogenesis of CA is complex, emerging studies suggest that endothelial progenitor cells (EPCs) play a crucial role. In this paper, we conducted a comprehensive literature review to investigate the potential role of EPCs in the pathogenesis and treatment of CA. Current research indicates that a decreased count and dysfunction of EPCs disrupt the balance between endothelial dysfunction and repair, thus increasing the risk of CA formation. Reversing these EPCs abnormalities may reduce the progression of vascular degeneration after aneurysm induction, indicating EPCs as a promising target for developing new therapeutic strategies to facilitate CA repair. This has motivated researchers to develop novel treatment options, including drug applications, endovascular-combined and tissue engineering therapies. Although preclinical studies have shown promising results, there is still a considerable way to go before clinical translation and eventual benefits for patients. Nonetheless, these findings offer hope for improving the treatment and management of this condition.

Liposomal nanocarriers of preassembled glycocalyx restore normal venular permeability and shear stress sensitivity in sepsis: assessed quantitatively with a novel microchamber system

The endothelial glycocalyx (EG), covering the luminal side of endothelial cells, regulates vascular permeability and senses wall shear stress. In sepsis, EG undergoes degradation leading to increased permeability and edema formation. We hypothesized that restoring EG integrity using liposomal nanocarriers of preassembled glycocalyx (LNPG) will restore normal venular permeability in lipopolysaccharide (LPS)-induced sepsis model of mice. To test this hypothesis, we designed a unique perfusion microchamber in which the permeability of isolated venules could be assessed by measuring the concentration of Evans blue dye (EBD) in microliter samples of extravascular solution (ES). Histamine-induced time- and dose-dependent increases in EBD in the ES could be measured, confirming the sensitivity of the microchamber system. Notably, the histamine-induced increase in permeability was significantly attenuated by histamine receptor (H1) antagonist, triprolidine hydrochloride. Subsequently, mice were treated with LPS or LPS + LNPG. When compared with control mice, venules from LPS-treated mice showed a significant increased permeability, which was significantly reduced by LNPG administration. Moreover, in the presence of wall shear stress, intraluminal administration of LNPG significantly reduced the permeability in isolated venules from LPS-treated mice. We have found no sex differences. In conclusion, our newly developed microchamber system allows us to quantitatively measure the permeability of isolated venules. LPS-induced sepsis increases permeability of mesenteric venules that is attenuated by in vivo LNPG administration, which also reestablished endothelial responses to shear stress. Thus, LNPG presents a promising therapeutic potential for restoring EG function and thereby mitigating vasogenic edema due to increased permeability in sepsis.NEW & NOTEWORTHY In sepsis, the degradation of the endothelial glycocalyx leads to increased venular permeability. In this study, we developed a potentially new therapeutic approach by in vivo administration of liposomal nanocarriers of preassembled glycocalyx to mice, which restored venular sensitivity to wall shear stress and permeability in lipopolysaccharide-induced sepsis, likely by restoring the integrity of the endothelial glycocalyx. Using a new microchamber system, the permeability of Evans blue dye could be quantitatively determined.