Wall Shear Stress Alteration: a Local Risk Factor of Atherosclerosis

Multidimensional excavation of the current status and trends of mechanobiology in cardiovascular homeostasis and remodeling within 20 years

Mechanobiology is essential for cardiovascular structure and function and regulates the normal physiological and pathological processes of the cardiovascular system. Cells in the cardiovascular system are extremely sensitive to their mechanical environment, and once mechanical stimulation is abnormal, the homeostasis mechanism is damaged or lost, leading to the occurrence of pathological remodeling diseases. In the past 20 years, many articles concerning the mechanobiology of cardiovascular homeostasis and remodeling have been published. To better understand the current development status, research hotspots and future development trends in the field, this paper uses CiteSpace software for bibliometric analysis, quantifies and visualizes the articles published in this field in the past 20 years, and reviews the research hotspots and emerging trends. The regulatory effects of mechanical stimulation on the biological behavior of endothelial cells, smooth muscle cells and the extracellular matrix, as well as the mechanical-related remodeling mechanism in heart failure, have always been research hotspots in this field. This paper reviews the research advances of these research hotspots in detail. This paper also introduces the research status of emerging hotspots, such as those related to cardiac fibrosis, homeostasis, mechanosensitive transcription factors and mechanosensitive ion channels. We hope to provide a systematic framework and new ideas for follow-up research on mechanobiology in the field of cardiovascular homeostasis and remodeling and promote the discovery of more therapeutic targets and novel markers of mechanobiology in the cardiovascular system.

Anti?atherosclerotic effect of aged garlic extract: Mode of action and therapeutic benefits (Review)

Atherosclerosis, a chronic inflammatory disease characterized by plaque buildup within the arteries that obstructs blood flow and significantly increases the morbidity and mortality rates associated with cardiovascular diseases caused by impaired blood flow due to vascular stenosis or occlusion, such as angina and myocardial infarction. The development of atherosclerosis involves a complex interplay of endothelial dysfunction, accumulation of oxidized low-density lipoprotein and macrophage-driven inflammation. The risk factors for atherosclerosis include chronic inflammation, hyperlipidemia and hypertension. Effective management of these risk factors can prevent and delay the onset and progression of atherosclerosis. Garlic and its processed preparations have previously been utilized to mitigate cardiovascular risk factors and continue to be used in traditional medicine in several countries. Among these preparations, aged garlic extract (AGE) has been shown to improve atherosclerosis in clinical trials and animal studies. AGE contains various compounds with potential anti-atherosclerotic properties, such as S-1-propenylcysteine, S-allylcysteine and other sulfur-containing constituents, which may help prevent the development and progression of atherosclerosis. The present manuscript reviewed and discussed the anti-atherogenic effect of AGE and its constituents by highlighting their mode of action and potential benefits for prevention and therapy in the management of atherosclerosis.

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.

Effect of plaque micro-watershed changes on carotid atherosclerosis

OBJECTIVE

The study aims to elucidate the mechanisms underlying plaque growth by analyzing the variations in hemodynamic parameters within the plaque region of patients' carotid arteries before and after the development of atherosclerotic lesions.

METHODS

The study enrolls 25 patients with common carotid artery stenosis and 25 with tandem carotid artery stenosis. Based on pathological analysis, three-dimensional models of the actual blood vessels before and after the lesion are constructed for two patients within a two-year period. Computational fluid dynamics is employed to conduct unsteady periodic non-Newtonian fluid numerical simulations, enabling an in-depth investigation into the changes in the micro-environment of blood flow.

RESULTS

During the systolic phase of the cardiac cycle, vortex regions are particularly prone to developing at the bifurcation point between the common carotid artery and the distal end of the internal carotid artery. In the early diastolic phase, blood reflux phenomena can be observed within the carotid artery. Towards the end of diastole, there is an expansion of vortex regions at the bifurcation point of the carotid artery. The shoulder region of initial small plaques within the blood vessel is susceptible to developing a low-speed recirculation zone, characterized by significantly reduced shear stress compared to the surrounding areas. Following vascular stenosis, the wall shear stress within the plaque domain generally increases; however, it maintains a consistent pattern of high central values and low upper shoulder values. The shear stress at the upper shoulder of the plaque of tandem carotid stenosis is below 0.4 Pa, whereas the central and lower shoulder regions exhibit shear stress exceeding 40 Pa.

CONCLUSIONS

The dynamic parameters of the blood flow micro-environment exhibit variations throughout the cardiac cycle, and temporal disparities exist in local lesions within the carotid artery. Both common and tandem carotid artery stenosis are particularly prone to developing lesions at the shoulder of initial small plaques. The micro-flow characteristics within the plaque domain undergo alterations prior to and following the onset of carotid artery disease. Furthermore, the occurrence of restenosis and rupture is associated with the location of plaque growth.

Influence of Geometric Parameters on the Hemodynamic Characteristics of the Vertebral Artery

The carotid arteries (CAs) and vertebral arteries (VAs) are principal conduits for cerebral blood supply and are common sites for atherosclerotic plaque formation. To date, there has been extensive clinical and hemodynamic reporting on carotid arteries; however, studies focusing on the hemodynamic characteristics of the VA are notably scarce. This article presents a systematic analysis of the impact of VA diameter and the angle of divergence from the subclavian artery (SA) on hemodynamic properties, facilitated by the construction of an idealized VA geometric model. Research indicates that the increase in the diameter of the VA is associated with a corresponding increase in the complexity of the vortex structures at the bifurcation with the SA. When the VA diameter is constant, a 30 deg VA-SA angle yields better hemodynamic capacity than 45 deg and 60 deg angles, and the patterns of blood flow and helicity values are consistent across different angles. Elevated oscillatory shear index (OSI) zones are mainly at the origin of the VA, with an elliptical low OSI region within. As the diameter increases, the high OSI region spreads downstream. Increasing the bifurcation angle decreases OSI values in and below the elliptical low OSI region. These findings are valuable for studying the physiological and pathological mechanisms of VA atherosclerosis.

Association of Subclavian Steal Phenomenon with Prevalence of Contralateral Vertebral Artery Atherosclerotic Stenosis: A Hospital-Based Cohort Study

AIMS

It is uncertain if there is a connection between subclavian steal phenomenon (SSP) and atherosclerotic stenosis in the opposite vertebral artery (VA). We aimed to explore the association between SSP and the incidence of contralateral vertebral artery stenosis (VAS) in vivo.

METHODS

In this prospective registry study, we included patients diagnosed with ＞50% stenosis of proximal subclavian artery (SA) or innominate artery (INA) by digital subtraction angiography (DSA) from our comprehensive stroke center between 2011 and 2022. VAS and SSP was diagnosed by DSA in the resting state. Propensity score matching (PSM) was conducted among all participants and subgroups with a 1:1 ratio according to the presence of SSP. We further conducted sensitivity analysis by dividing all participants into subgroups according to the degree of stenosis and type of SSP. Binomial logistic regression analysis was applied to investigate the association of SSP with contralateral VAS.

RESULTS

A total of 774 patients were included in this study and 309 (39.9%) were found with SSP. After PSM, presence of SSP was associated with lower prevalence of contralateral VAS among all participants (OR 0.45; 95% CI 0.31-0.65; p＜0.001). In subgroup analysis, the association was respectively found within left subclavian (LSA) stenosis group (OR 0.43; 95% CI 0.29-0.65; P＜0.001) and right subclavian artery (RSA) / INA stenosis group (OR 0.36; 95% CI 0.19-0.69; P=0.002).

CONCLUSIONS

SSP is associated with lower prevalence of contralateral VAS.

Recent Advances in Micro/Nanomotor for the Therapy and Diagnosis of Atherosclerosis

Atherosclerotic cardiovascular disease poses a significant global public health threat with a high incidence that can result in severe mortality and disability. The lack of targeted effects from traditional therapeutic drugs on atherosclerosis may cause damage to other organs and tissues, necessitating the need for a more focused approach to address this dilemma. Micro/nanomotors are self-propelled micro/nanoscale devices capable of converting external energy into autonomous movement, which offers advantages in enhancing penetration depth and retention while increasing contact area with abnormal sites, such as atherosclerotic plaque, inflammation, and thrombosis, within blood vessel walls. Recent studies have demonstrated the crucial role micro/nanomotors play in treating atherosclerotic cardiovascular disease. Hence, this review highlights the recent progress of micro/nanomotor technology in atherosclerotic cardiovascular disease, including the effective promotion of micro/nanomotors in the circulatory system, overcoming hemorheological barriers, targeting the atherosclerotic plaque microenvironment, and targeting intracellular drug delivery, to facilitate atherosclerotic plaque localization and therapy. Furthermore, we also describe the potential application of micro/nanomotors in the imaging of vulnerable plaque. Finally, we discuss key challenges and prospects for treating atherosclerotic cardiovascular disease while emphasizing the importance of designing individualized management strategies specific to its causes and microenvironmental factors.

Hemodynamics are associated with subsequent lumen remodeling and clinical maturation of hemodialysis arteriovenous fistula

The pathogenesis of arteriovenous fistula (AVF) maturation failure is unclear. We evaluated the associations of wall shear stress (WSS) with subsequent AVF remodeling and clinical maturation using regression models in this prospective cohort study. Participants underwent duplex ultrasound at postoperative Day 1, Week 2, and Week 6 to measure AVF blood flow rate and diameter of the draining vein and proximal artery. The median vein WSS of 602 participants decreased from Day 1 to Week 6 (from 33.4 to 21.6 dyne/cm2) but did not change noticeably for the artery (from 58.4 to 55.1 dyne/cm2). WSS was positively associated with subsequent lumen expansion, with doubling of Day-1 WSS presaging a 9% (95% confidence interval (CI) 5%-14%; P < 0.001) greater Day 1-to-Week 6 increase in vein lumen cross-sectional area and a 5% (95% CI: 1%-10%; P = 0.020) greater increase in artery lumen area. The odds of unassisted clinical maturation increased by 45% (95% CI: 11%-89%; P = 0.006) with each doubling of Day-1 vein WSS, and by 82% (95% CI: 39%-250%; P < 0.001) with each doubling of Day-1 artery WSS. These findings show that WSS was positively associated with subsequent lumen expansion and AVF unassisted clinical maturation.

Evaluation of Carotid Stenosis in a High-Stroke-Risk Population by Hemodynamic Dual-Parameters Based on Ultrasound Vector Flow Imaging

OBJECTIVE

This study explored the feasibility of using high-frame-rate ultrasound vector flow imaging (VFI) to quantitatively assess hemodynamics in atherosclerotic internal carotid artery stenosis (ICAS) by evaluating dual-parameters, turbulence index (Tur), and wall shear stress (WSS). Their efficacy in evaluating carotid artery stenosis was also analyzed.

METHODS

Fifty-nine patients with ICAS were enrolled. B-mode ultrasound and V Flow (a high-frame-rate VFI) were performed using the Resona R9 system. The stenosis rate was measured in grayscale mode, whereas the time-averaged Tur index, the time-averaged WSS (WSSmean), and maximum WSS (WSSmax) around stenosis were measured. The combined diagnostic efficacy of Tur inand WSS was also investigated.

RESULTS

Compared to proximal to stenosis (Tur index, 2.88% ± 3.65%), highly disordered blood flow was observed in the stenotic (23.17% ± 15.52%, p < 0.001) and distal segment (25.86% ± 17.29%, p < 0.001). WSSmax ([11.91 ± 6.73] vs. [4.43 ± 5.4] Pa, p < 0.001) and WSSmean ([3.42 ± 2.67] vs. [0.86 ± 1.21] Pa, p < 0.001) were significantly bigger in stenotic than those in the distal segment. The differences in the ratio WSSmax/Tur or WSSmean/Tur among different segments around stenosis were statistically significant (p < 0.001). The combination of Tur index and WSS had the best diagnostic performance in ICAS (AUC, 0.899).

CONCLUSION

The application of Tur index and WSS for quantitative assessment of ICAS hemodynamic changes is feasible, with the combined evaluation of these two parameters providing incremental diagnostic value for carotid artery stenosis. VFI-based dual quantitative parameters may offer promising noninvasive diagnostic tools for carotid artery stenosis in high-stroke-risk populations.

Predicting vulnerable carotid plaques by detecting wall shear stress based on ultrasonic vector flow imaging

OBJECTIVE

Carotid plaque vulnerability is a significant factor in the risk of cardiocerebrovascular events, with intraplaque neovascularization (IPN) being a crucial characteristic of plaque vulnerability. This study investigates the value of ultrasound vector flow imaging (V-flow) for measuring carotid plaque wall shear stress (WSS) in predicting the extent of IPN.

METHODS

We enrolled 140 patients into three groups: 53 in the plaque group (72 plaques), 23 in the stenosis group (27 plaques), and 64 in the control group. V-flow was used to measure WSS parameters, including the average WSS (WSS mean) and the maximum WSS (WSS max), across three plaque locations: mid-upstream, maximum thickness, and mid-downstream. Contrast-enhanced ultrasound examination was used in 76 patients to analyze IPN and its correlation with WSS parameters.

RESULTS

WSS max in the stenosis group was significantly higher than that in the control and plaque groups at the maximum thickness part (P < .05) and WSS mean in the stenosis group was significantly lower than that in the control group at the mid-upstream and mid-downstream segments (P < .05). WSS mean in the plaque group was significantly lower than that of the control group at all three locations (P < .05). Contrast-enhanced ultrasound examination revealed that plaques with neovascularization enhancement exhibited significantly higher WSS values (P < .05), with a positive correlation between WSS parameters and IPN enhancement grades, particularly WSS max at the thickest part (r = 0.508). Receiver operating characteristic curve analysis of WSS parameters for evaluating IPN showed that the efficacy of WSS max in evaluating IPN was better than that of WSS mean (P < .05), with an area under the curve of 0.7762 and 0.6973 (95% confidence intervals, 0.725-0.822 and 0.642-0.749, respectively). The cut-offs were 4.57 Pa and 1.12 Pa, sensitivities were 74.03% and 63.64%, and specificities were 75.00% and 68.18%.

CONCLUSIONS

V-flow effectively measures WSS in carotid plaques. WSS max provides a promising metric for assessing IPN, offering potential insights into plaque characteristics and showing some potential in predicting plaque vulnerability.

Targeted Delivery of Nanoparticles to Blood Vessels for the Treatment of Atherosclerosis

Atherosclerosis is a common form of cardiovascular disease, which is one of the most prevalent causes of death worldwide, particularly among older individuals. Surgery is the mainstay of treatment for severe stenotic lesions, though the rate of restenosis remains relatively high. Current medication therapy for atherosclerosis has limited efficacy in reversing the formation of atherosclerotic plaques. The search for new drug treatment options is imminent. Some potent medications have shown surprising therapeutic benefits in inhibiting inflammation and endothelial proliferation in plaques. Unfortunately, their use is restricted due to notable dose-dependent systemic side effects or degradation. Nevertheless, with advances in nanotechnology, an increasing number of nano-related medical applications are emerging, such as nano-drug delivery, nano-imaging, nanorobots, and so forth, which allow for restrictions on the use of novel atherosclerotic drugs to be lifted. This paper reviews new perspectives on the targeted delivery of nanoparticles to blood vessels for the treatment of atherosclerosis in both systemic and local drug delivery. In systemic drug delivery, nanoparticles inhibit drug degradation and reduce systemic toxicity through passive and active pathways. To further enhance the precise release of drugs, the localized delivery of nanoparticles can also be accomplished through blood vessel wall injection or using endovascular interventional devices coated with nanoparticles. Overall, nanotechnology holds boundless potential for the diagnosis and treatment of atherosclerotic diseases in the future.

Evaluafion of the efficacy of wall shear stress in carotid artery stenting

Objective

To characterize the value of carotid wall shear stress (WSS) following carotid artery stenting (CAS) in patients with carotid stenosis.

Methods

Twenty-eight patients with carotid stenosis treated with CAS between March 2021 to May 2022 in the eighth medical center of the PLA General Hospital were selected for our study. Carotid ultrasound was performed before the operation, one week post-operation, and six months post-operation. Carotid artery WSS was detected by blood flow vector imaging, and the changes in WSS before and after the operation were collected. Genetic testing of drugs was detected for patients with restenosis.

Results

Pre-operative WSS of the proximal, narrowest region, and distal carotid arteries in patients with ischemic carotid artery stenosis was 7.88 ± 3.18Pa, 14.36 ± 6.66Pa, and 1.55 ± 1.15Pa, respectively. Comparatively, pre-operative WSS of the proximal, narrowest region and distal carotid arteries in patients without ischemic symptoms was 5.02 ± 1.99Pa, 9.68 ± 4.23Pa, and 1.10 ± 0.68Pa, respectively, with a significant difference between the two groups (p < 0.001). Overall WSS of the proximal, narrowest region, and distal carotid arteries in patients before CAS was 6.68 ± 3.0Pa, 12.47 ± 5.98Pa, and 1.39 ± 0. 96Pa. WSS of the proximal, narrowest region, and distal carotid was 4.15 ± 1.42Pa, 6.71 ± 2.64Pa, and1.86 ± 1.13Pa one week after CAS, compared to 4.44 ± 1.91Pa, 7.90 ± 4.38Pa, and 2. 36 ± 1.09Pa six months after CAS. WSS of the proximal and narrowest region of the carotid artery was reduced after carotid stenting, and the difference was statistically significant (p < 0.001). There was no statistically significant difference in WSS between one week and six months after stenting (P > 0.05).

Conclusion

We employed early carotid WSS as a means of evaluating the efficacy of carotid artery stenting. Changes in carotid WSS are closely associated with carotid artery stenosis, providing valuable hemodynamic information for CAS treatment. This technique holds great application value in pre-operative evaluation and long-term follow-up.

A dual-targeting therapeutic nanobubble for imaging-guided atherosclerosis treatment

Atherosclerosis is a cardiovascular disease that seriously endangers human health. Low shear stress (LSS) is recognized as a vital factor in causing chronic inflammatory and further inducing the occurrence and development of atherosclerosis. Targeting imaging and treatment are of substantial significance for the diagnosis and therapy of atherosclerosis. On this ground, a kind of ultrasound (US) imaging-guided therapeutic polymer nanobubbles (NBs) with dual targeting of magnetism and antibody was rationally designed and constructed for the efficiently treating LSS-mediated atherosclerosis. Under the combined targeting effect of an external magnetic field and antibodies, the drug-loaded therapeutic NBs can be effectively accumulated in the inflammatory area caused by LSS. Upon US irradiation, the NBs can be selectively disrupted, leading to the rapid release of the loaded drugs at the targeted site. Notably, the US irradiation generates a cavitation effect that induces repairable micro gaps in nearby cells, thereby enhancing the uptake of released drugs and further improving the therapeutic effect. The prominent US imaging, efficient anti-inflammatory effect and treatment outcome of LSS-mediated atherosclerosis had been verified in vivo on a surgically constructed LSS-atherosclerosis animal model. This work showcased the potential of the designed NBs with multifunctionality for in vivo imaging, dual-targeting, and drug delivery in the treatment of atherosclerosis.

Numerical simulation of cellular blood flow in curved micro-vessels with saccular aneurysms: Effect of curvature degree and hematocrit level

The dynamics of cellular blood flow in curved vessels considerably differ from those in straight vessels. It is reported that clotting development is significantly affected by vessel shape irregularities. Thus, the current study aims to investigate the effect of curvature degree and hematocrit level on cellular blood flow in a curved micro-vessel with a saccular aneurysm. Accordingly, a three-dimensional numerical simulation is performed using a validated code developed for cellular blood flow problems. The obtained results show that the cell-free layer thickness is highly dependent on the curvature degree and hematocrit level, which may have a remarkable impact on the apparent viscosity of blood as well as the dynamics of other particles such as drug particulates. The near-wall region exhibits the highest degree of cell deformation, whereas the red blood cells within the aneurysm zone remain nearly undeformed. Meanwhile, the velocity of the red blood cells decreases with the increase in curvature degree, which can affect the quality of the oxygenation process. Because of the saccular aneurysm, a considerable decrease in plasma velocity is predicted. Moreover, no secondary flows are detected in the curved vessel except in the aneurysm zone. An increase in the curvature degree is expected to reduce the blood flow rate by about 10%. Furthermore, low wall shear stress values are predicted in the straight case compared to the values at the apex of the curved vessel, which may affect the structure and function of the endothelial cells of the vessel wall and, hence, increase the aneurysm rupture possibility.

Biomechanics-mediated endocytosis in atherosclerosis

Biomechanical forces, including vascular shear stress, cyclic stretching, and extracellular matrix stiffness, which influence mechanosensitive channels in the plasma membrane, determine cell function in atherosclerosis. Being highly associated with the formation of atherosclerotic plaques, endocytosis is the key point in molecule and macromolecule trafficking, which plays an important role in lipid transportation. The process of endocytosis relies on the mobility and tension of the plasma membrane, which is sensitive to biomechanical forces. Several studies have advanced the signal transduction between endocytosis and biomechanics to elaborate the developmental role of atherosclerosis. Meanwhile, increased plaque growth also results in changes in the structure, composition and morphology of the coronary artery that contribute to the alteration of arterial biomechanics. These cross-links of biomechanics and endocytosis in atherosclerotic plaques play an important role in cell function, such as cell phenotype switching, foam cell formation, and lipoprotein transportation. We propose that biomechanical force activates the endocytosis of vascular cells and plays an important role in the development of atherosclerosis.

Structural and Mechanical Properties of Human Superficial Femoral and Popliteal Arteries

The femoropopliteal artery (FPA) is the main artery in the lower limb. It supplies blood to the leg muscles and undergoes complex deformations during limb flexion. Atherosclerotic disease of the FPA (peripheral arterial disease, PAD) is a major public health burden, and despite advances in surgical and interventional therapies, the clinical outcomes of PAD repairs continue to be suboptimal, particularly in challenging calcified lesions and biomechanically active locations. A better understanding of human FPA mechanical and structural characteristics in relation to age, risk factors, and the severity of vascular disease can help develop more effective and longer-lasting treatments through computational modeling and device optimization. This review aims to summarize recent research on the main biomechanical and structural properties of human superficial femoral and popliteal arteries that comprise the FPA and describe their anatomy, composition, and mechanical behavior under different conditions.

Increased Cardiovascular Risk in Young Patients with CKD and the Role of Lipid-Lowering Therapy

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with a significantly increased risk of cardiovascular disease (CVD). This review summarizes known risk factors, pathophysiological mechanisms, and current therapeutic possibilities, focusing on lipid-lowering therapy in CKD.

RECENT FINDINGS

Novel data on lipid-lowering therapy in CKD mainly stem from clinical trials and clinical studies. In addition to traditional CVD risk factors, patients with CKD often present with non-traditional risk factors that include, e.g., anemia, proteinuria, or calcium-phosphate imbalance. Dyslipidemia remains an important contributing CVD risk factor in CKD, although the mechanisms involved differ from the general population. While statins are the most commonly used lipid-lowering therapy in CKD patients, some statins may require dose reduction. Importantly, statins showed diminished beneficial effect on cardiovascular events in patients with severe CKD and hypercholesterolemia despite high CVD risk and effective reduction of LDL cholesterol. Ezetimibe enables the reduction of the dose of statins and their putative toxicity and, in combination with statins, reduces CVD endpoints in CKD patients. The use of novel drugs such as PCSK9 inhibitors is safe in CKD, but their potential to reduce cardiovascular events in CKD needs to be elucidated in future studies.

The differences between carotid web and carotid web with plaque: based on multimodal ultrasonic and clinical characteristics

OBJECTIVE

This study aimed to examine the clinical and multimodal ultrasonic characteristics differences between carotid web (CW) and CW with plaque as well as the potential risk factors for stroke caused by CW.

METHODS

We retrospectively enrolled patients diagnosed with CW by CTA or high-resolution MRI (HRMRI) and simultaneously underwent contrast enhanced ultrasound (CEUS) and superb microvascular imaging examinations from January 2015 to October 2022. The CW angle was measured using computer-aided software. The variations between CW and CW with plaque were evaluated, and univariable and multivariable logistic regressions were utilized to identify possible risk predictors for stroke caused by CW.

RESULTS

Two hundred ninety-nine patients with an average age of 60.85 (± 8.77) years were included. Sex, age, history of smoking, alcohol, hypertension, diabetes mellitus, homocysteine level, and treatment, as well as web length and thickness, luminal stenosis, location wall, number, CW angle, and CEUS enhancement, were quite different among CW and CW with plaque patients (p < 0.05). The logistic regression analysis showed that web length was an independent predictor of luminal stenosis in CW patients. For patients with CW and plaque, plaque and web thickness, as well as plaque enhancement, were associated with stenosis. Furthermore, luminal stenosis and plaque length were risk factors for symptoms.

CONCLUSION

The multimodal ultrasonic and clinical manifestations of CW and CW with plaque are quite different. Web length is an independent risk factor for carotid artery stenosis in CW patients, whereas luminal stenosis and plaque length were risk factors for symptoms in CW with plaque patients.

CRITICAL RELEVANCE STATEMENT

Exploring the similarities and differences between the carotid web and the carotid web with plaque, based on the stereo-geometric spatial position relationship and hemodynamic changes, may provide further insights into the underlying mechanisms of stroke occurrence caused by the carotid web.

KEY POINTS

1. Multimodal ultrasonic and clinical manifestations of carotid web and carotid web with plaque are substantially different. 2. A thin triangular endoluminal defect is identified as a typical feature of the web on superb microvascular imaging, and two kinds of typical ultrasonic features of CW with plaque are also identified. 3. Web length is an independent risk factor for carotid stenosis in carotid web patients, whereas luminal stenosis and plaque length are risk factors for symptoms in patients with CW and plaque.

In silico hemodynamical simulations show additional benefits of artery wall softening induced by antihypertensive drugs

BACKGROUND AND OBJECTIVES

Age-related arterial stiffening increases peripheral resistance and decreases arterial distensibility, thus contributing to hypertension, an important risk factor of atherosclerosis. It causes abnormal blood flow, endothelial dysfunction, higher pulse wave velocity, and consequently elevated pressure wave amplitude.

METHODS

This paper presents the influence of these changes via multiscale 3D-0D transient computational fluid dynamics simulations of blood flow in five patient-specific geometries of human carotid bifurcation using archetypal flow waveforms for young and old subjects.

RESULTS

The proposed model shows a significant decrease in the time-averaged wall shear stress (TAWSS) for the old archetypal flow waveform. This is in good agreement with clinical data on a straight segment of common carotid arteries available for young and old subjects. Moreover, our study showed that the decrease of area-averaged TAWSS related to the old flow waveform is much more pronounced (2.5 ÷ 4.5 times higher) at risk areas (areas showing TAWSS below its threshold value of 0.48 Pa) than in straight segments commonly considered in clinical studies.

CONCLUSIONS

Since arterial stiffness can be lowered through long-term usage of any of the five basic groups of antihypertensives, possible benefits of such medical therapy could be not only lowering blood pressure and peripheral resistance but also in increasing the TAWSS and thus attenuating an important mechanism of the atherosclerotic process.

Impact of craniocervical junction abnormality on vertebral artery hemodynamics: based on computational fluid dynamics analysis

Background and purpose

A three-dimensional reconstruction and data analysis of the vertebral artery (VA) with craniocervical junction abnormality (CJA) was performed by computational fluid dynamics (CFD) based on images to assess the impact of CJA on vertebral artery hemodynamics.

Methods

Retrospective analysis of combined head and neck computed tomography angiography (CTA) images of 60 patients with CJA and 60 normal patients admitted to our department from January 2018 to June 2022. The VA was reconstructed in three dimensions using CFD-related software, and the results were visualized to derive vertebral artery lumen diameter (D), peak systolic velocity (PSV), mean blood flow velocity (MV), wall pressure (P), wall shear stress (WSS), normalized WSS (NWSS), etc. Statistical analysis was used to analyze whether the data related to hemodynamics in the CJA group and the control group were statistically significant.

Results

The lumen diameter of the vertebral artery in the CJA group were less than the control group, and the difference was statistically significant (3.354 ± 0.562 vs. 3.744 ± 0.520, p < 0.05); the PSV, MV, P, WSS, and NWSS of the CJA group were increased compared with the control group, and the difference was statistically significant (1.235 ± 0.182 vs. 1.104 ± 0.145, 0.339 ± 0.063 vs. 0.307 ± 0.042, 24576.980 ± 7095.836 vs. 20824.281 ± 6718.438, 34.863 ± 6.816 vs. 31.080 ± 5.438, 0.272 ± 0.075 vs. 0.237 ± 0.067, p < 0.05).

Conclusion

In the complex CJA, the possibility of hemodynamic variation in the VAs is higher than in the normal population. The hemodynamic aspects of the vertebral artery in patients with CJA, such as diameter, flow velocity, flow, wall pressure and shear force, differ from those in the normal population and may lead to the occurrence of clinical symptoms, such as dizziness, so preoperative examinations such as combined head and neck CTA should be performed to clarify the vascular abnormalities.

Local carotid stiffness, hemodynamic forces and blood viscosity in patients with cerebral lacunar infarctions

OBJECTIVE

The carotid stiffness is an important factor in the pathogenesis of cerebrovascular small vessel disease. Our study aimed to evaluate the relation of the local arterial stiffness of the common carotid artery (CCA) to the hemodynamic forces and blood viscosity in patients with cerebral lacunar infarctions (LI).

METHODS

Twenty-two patients with chronic LI and 15 age-matched controls were examined. An ultrasound examination of the CCA intima-media thickness (IMT), the parameters of local CCA stiffness: distensibility (DC) and compliance coefficients (CC), α and β stiffness indices and pulse wave velocity (PWV) was performed. The local hemodynamic forces were calculated: circumferential wall tension (CWT) and wall shear stress (WSS). Whole blood viscosity (WBV) and shear stresses at shear rates of 0.277 s- 1 to 94.5 s- 1 were measured in patients and controls.

RESULTS

Higher values of IMT, a significant decrease of DC and CC and an increase of α and β stiffness indices and PWV in the LI patients compared to the controls were obtained. A parallel significant increase in CWT and a decrease in WSS was found. An increase in WBV and a significant increase in shear stresses were detected. In the LI patients, the increased stiffness indices were associated with an increase in age, cholesterol and WBV at higher shear rates in the left CCA. In the controls, the IMT and stiffness indices correlated significantly with the hemodynamic factors and WBV in both CCAs, while the stiffness indices correlated with the hemodynamic forces in the left CCA.

CONCLUSION

The results of the present study demonstrate different associations of the local carotid stiffness indices with the hemodynamic forces and WBV in patients with LI and controls.

Apolipoprotein E-depletion accelerates arterial fat deposition in the spontaneously hypertensive rat

Hypertension and atherosclerosis are often found in one patient causing serious cardiovascular events. An animal model simultaneously expressing hypertension and atherosclerosis would be useful to study such a complex risk status. We therefore attempted to introduce a null mutation of the apolipoprotein E (ApoE) gene into the spontaneously hypertensive rat (SHR) using CRISPR/Cas9 to establish a genetic model for atherosclerosis with hypertension. We successfully established SHRApoE(-/-) having a 13-bps deletion in the 5'-end of ApoE gene. Deletion of ApoE protein was confirmed by Western blotting. Blood pressure of SHRApoE(-/-) was comparable to that of SHR. Feeding the rats with high fat high cholesterol diet (HFD) caused a significant increase in LDL cholesterol as well as in triglyceride in SHRApoE(-/-). After 8 weeks of HFD loading, superficial fat deposition was observed both in the aorta and the mesenteric arteries of SHRApoE(-/-) instead of mature atheromatous lesions found in humans. In addition, a null mutation of peroxiredoxin 2 (Prdx2) was introduced into SHRApoE(-/-) to examine the effect of increased oxidative stress on the development of atherosclerosis. SHR with the double depletion of ApoE and Prdx2 did not show mature atheroma either. Further, salt loading did not promote development of atheroma although it accelerated the development of fat deposition. These results indicated that when compared with ApoE-knockout mice, SHRApoE(-/-) was more resistant to atherosclerosis even though they have severe hypertension.

Characteristics and evaluation of atherosclerotic plaques: an overview of state-of-the-art techniques

Atherosclerosis is an important cause of cerebrovascular and cardiovascular disease (CVD). Lipid infiltration, inflammation, and altered vascular stress are the critical mechanisms that cause atherosclerotic plaque formation. The hallmarks of the progression of atherosclerosis include plaque ulceration, rupture, neovascularization, and intraplaque hemorrhage, all of which are closely associated with the occurrence of CVD. Assessing the severity of atherosclerosis and plaque vulnerability is crucial for the prevention and treatment of CVD. Integrating imaging techniques for evaluating the characteristics of atherosclerotic plaques with computer simulations yields insights into plaque inflammation levels, spatial morphology, and intravascular stress distribution, resulting in a more realistic and accurate estimation of plaque state. Here, we review the characteristics and advancing techniques used to analyze intracranial and extracranial atherosclerotic plaques to provide a comprehensive understanding of atheroma.

Microfluidic-to-macrofluidic: A simple in vitro model of atherosclerosis induced by fluidic stimulation

Atherosclerosis is the narrowing of the arteries due to the formation of fatty plaques, which is the main cause of myocardial infarction and stroke. It is important to develop an in vitro model that can combine multiple-type cell co-culture, vessel wall-like structure, and fluid condition to simulate the processes of atherosclerosis. Herein, we used a simple microfluidic chip made of three polydimethylsiloxane layers to co-culture endothelial and smooth muscle cells in a flat rectangular microchannel. After being connected with a circulating culture medium driven by a peristaltic pump, the flat microchannel was deformed to a tunnel-like macrochannel. The fluid pressure and shear stress applied on the cells in the deformed macrochannel can be varied by adjusting the circulating flow rate and the thickness of the middle layer. Under three levels of the pressure (65, 131, and 196 mm Hg) or shear stress (0.99, 4.78, and 24 dyne/cm2) conditions, a series of atherosclerosis-related events, including endothelial cell junction, pro-inflammatory cytokine secretion, monocyte adhesion, and lipid accumulation, were investigated. The atherosclerosis-related results showed that the medium pressure or shear stress exhibited a relatively weak pro-atherosclerotic effect in a V-shaped trend. To demonstrate the potential in drug screen, the effects of three well-known anti-atherosclerotic drugs (atorvastatin, tetramethylpyrazine, and high-density lipoprotein) on the lipid accumulation and pro-inflammatory cytokine secretion were evaluated under a strong pro-atherosclerotic fluid condition (65 mm Hg, 0.99 dyne/cm2). This in vitro model of atherosclerosis has shown great potential in drug screen application.

Associations of plaque morphology and location with Intraplaque neovascularization in the carotid artery by contrast-enhanced ultrasound imaging

Objective

Intraplaque neovascularization (IPN) is a known indicator of plaque vulnerability, and is thus considered a predictor of stroke. The morphology and location of the carotid plaque may be correlated with plaque vulnerability. Therefore, our study aimed to examine the associations of carotid plaque morphology and location with IPN.

Methods

A total of 141 patients with carotid atherosclerosis (mean age, 64.99 ± 10.96 years) who underwent carotid contrast-enhanced ultrasound (CEUS) between November 2021 and March 2022 were retrospectively analyzed. IPN was graded according to the presence and location of microbubbles within the plaque. The association of IPN grade with carotid plaque morphology and location was evaluated using ordered logistic regression.

Results

Of the 171 plaques, 89 (52%) were IPN Grade 0, 21 (12.2%) were Grade 1, and 61 (35.6%) were Grade 2. IPN grade significantly associated with both plaque morphology and location, with higher grades observed among Type III morphology and common carotid artery plaques. Significant negative association was further shown between IPN grade and serum high-density lipoprotein cholesterol (HDL-C) level. Plaque morphology and location, and HDL-C remained significantly associated with IPN grade after adjusting for confounding factors.

Conclusion

The location and morphology of carotid plaques were significantly associated with the IPN grade on CEUS, and therefore show potential as biomarkers for plaque vulnerability. Serum HDL-C was also identified as a protective factor against IPN, and may play a role in the management of carotid atherosclerosis. Our study provided a potential strategy for identification of vulnerable carotid plaques and elucidated the important imaging predictors of stroke.

Modularized dynamic cell culture platform for efficient production of extracellular vesicles and sequential analysis

Extracellular vesicles (EVs) are nanometer-sized particles naturally secreted by cells for intercellular communication that encapsulate bioactive cargo, such as proteins and RNA, with a lipid bilayer. Tumor cell-derived EVs (tdEVs) are particularly promising biomarkers for cancer research because their contents reflect the cell of origin. In most studies, tdEVs have been obtained from cancer cells cultured under static conditions, thus lacking the ability to recapitulate the microenvironment of cells in vivo. Recent developments in perfusable cell culture systems have allowed oxygen and a nutrient gradient to mimic the physiological and cellular microenvironment. However, as these systems are perfused by circulating the culture medium within the unified structure, independently harvesting cells and EVs at each time point for analysis presents a limitation. In this study, a modularized cell culture system is designed for the perfusion and real-time collection of EVs. The system consists of three detachable chambers, one each for fresh medium, cell culture, and EV collection. The fresh medium flows from the medium chamber to the culture chamber at a flow rate controlled by the hydraulic pressure injected with a syringe pump. When the culture medium containing EVs exceeds a certain volume within the chamber, it overflows into the collection chamber to harvest EVs. The compact and modularized chambers are highly interoperable with conventional cell culture modalities used in the laboratory, thus enabling various EV-based assays.

The role of the blood-brain barrier during neurological disease and infection

A healthy brain is protected by the blood-brain barrier (BBB), which is formed by the endothelial cells that line brain capillaries. The BBB plays an extremely important role in supporting normal neuronal function by maintaining the homeostasis of the brain microenvironment and restricting pathogen and toxin entry to the brain. Dysfunction of this highly complex and regulated structure can be life threatening. BBB dysfunction is implicated in many neurological diseases such as stroke, Alzheimer's disease, multiple sclerosis, and brain infections. Among other mechanisms, inflammation and/or flow disturbances are major causes of BBB dysfunction in neurological infections and diseases. In particular, in ischaemic stroke, both inflammation and flow disturbances contribute to BBB disruption, leading to devastating consequences. While a transient or minor disruption to the barrier function could be tolerated, chronic or a total breach of the barrier can result in irreversible brain damage. It is worth noting that timing and extent of BBB disruption play an important role in the process of any repair of brain damage and treatment strategies. This review evaluates and summarises some of the latest research on the role of the BBB during neurological disease and infection with a focus on the effects of inflammation and flow disturbances on the BBB. The BBB's crucial role in protecting the brain is also the bottleneck in central nervous system drug development. Therefore, innovative strategies to carry therapeutics across the BBB and novel models to screen drugs, and to study the complex, overlapping mechanisms of BBB disruption are urgently needed.

A non-linear relationship between lesion length and risk of recurrent cerebral ischemia after stenting for symptomatic intracranial stenosis with hemodynamic impairment

Background

Stent placement can be an effective treatment for patients with symptomatic intracranial stenosis (sICAS) and hemodynamic impairment (HI). However, the association between lesion length and the risk of recurrent cerebral ischemia (RCI) after stenting remains controversial. Exploring this association can help predict patients at higher risk for RCI and develop individualized follow-up schedules.

Method

In this study, we provided a post-hoc analysis of a prospective, multicenter registry study on stenting for sICAS with HI in China. Demographics, vascular risk factors, clinical variables, lesions, and procedure-specific variables were recorded. RCI includes ischemic stroke and transient ischemic attack (TIA), from month 1 after stenting to the end of the follow-up period. Smoothing curve fitting and segmented Cox regression analysis were used to analyze the threshold effect between lesion length and RCI in the overall group and subgroups of the stent type.

Results

The non-linear relationship between lesion length and RCI was observed in the overall population and subgroups; however, the non-linear relationship differed by subgroup of stent type. In the balloon-expandable stent (BES) subgroup, the risk of RCI increased 2.17-fold and 3.17-fold for each 1-mm increase in the lesion length when the lesion length was <7.70 mm and >9.00 mm, respectively. In the self-expanding stent (SES) subgroup, the risk of RCI increased 1.83-fold for each 1-mm increase in the lesion length when the length was <9.00 mm. Nevertheless, the risk of RCI did not increase with the length when the lesion length was >9.00mm.

Conclusion

A non-linear relationship exists between lesion length and RCI after stenting for sICAS with HI. The lesion length increases the overall risk of RCI for BES and for SES when the length was <9.00 mm, while no significant relationship was found when the length was >9.00 mm for SES.

Distribution and regional variation of wall shear stress in the curved middle cerebral artery using four-dimensional flow magnetic resonance imaging

BACKGROUND

To investigate the distribution and regional variation of wall shear stress (WSS) in the curved middle cerebral artery (MCA) in healthy individuals using four-dimensional (4D) flow magnetic resonance imaging (MRI).

METHODS

A total of 44 healthy participants (18 males; mean ages: 27.16±5.69 years) were included in this cross-sectional study. The WSS parameters of mean, minimum, and maximum values, the coefficient of variation of time-averaged WSS (TAWSSCV), and the maximum values of the oscillatory shear index (OSI) were calculated and compared in the curved proximal (M1) segments. Three cross-sectional planes were selected: the location perpendicular to the beginning of the long axis of the curved M1 segment of the MCA (proximal section), the most curved M1 location (curved M1 section), and the location before the insular (M2) segment bifurcation (distal section). The WSS and OSI parameters of the proximal, curved, and distal sections of the curved M1 segment were compared, including the inner and outer curvatures of the curved M1 section.

RESULTS

Of the curved M1 segments, the curved M1 section had significantly lower minimum TAWSS values than the proximal (P=0.031) and distal sections (P=0.002), and the curved M1 section had significantly higher maximum OSI values than the distal section (P=0.001). The TAWSSCV values at the curved M1 section were significantly higher than the proximal (P=0.001) and distal sections (P<0.001). At the curved M1 section, the inner curvature showed a significantly lower minimum TAWSS (P=0.013) and higher maximum OSI values (P=0.002) than the outer curvature.

CONCLUSIONS

There are distribution variation of WSS and OSI parameters at the curved M1 section of the curved MCA, and the inner curvature of the curved M1 section has the lowest WSS and highest OSI distribution. The local hemodynamic features of the curved MCA may be related to the predilection for atherosclerotic plaque development.

Junctional Adhesion Molecules: Potential Proteins in Atherosclerosis

Junctional adhesion molecules (JAMs) are cell-cell adhesion molecules of the immunoglobulin superfamily and are involved in the regulation of diverse atherosclerosis-related processes such as endothelial barrier maintenance, leucocytes transendothelial migration, and angiogenesis. To combine and further broaden related results, this review concluded the recent progress in the roles of JAMs and predicted future studies of JAMs in the development of atherosclerosis.