Microfluidics-based study on the damage pattern of red blood cells and VWF / 国际生物医学工程杂志

Objective:To investigate the effects of shear stress magnitude and exposure time on the damage of blood component erythrocytes and von willebrand factor (VWF) based on microfluidic technology.Methods:A blood shear platform was built based on a microfluidic chip, samples were prepared under different shear stress magnitudes and exposure time lengths, free hemoglobin assay experiments were performed on blood samples, the hemolysis indices of different samples were measured, and the relative molecular masses of different samples of VWF were analyzed by immunoblotting and chemiluminescence imaging.Results:The quantitative relationships between the hemolysis index and the degradation rate of high relative molecular mass VWF with shear stress and exposure time followed the power function model well.Conclusions:The microfluidic experimental platform has the advantages of a precise and controllable internal microenvironment and easy and rapid detection, which can be used for the quantitative study of blood damage patterns.

Application of Biomechanical Stress from Coronary Computed Tomography Angiography in Coronary Plaque Assessment and Prediction of Adverse Cardiovascular Events / 医用生物力学

Long-term exposure to risk factors will lead to coronary atherosclerosis, which will lead to the formation and progression of coronary plaque. Early identification of high-risk plaque characteristics will help prevent plaque rupture or erosion, thus avoiding the occurrence of acute cardiovascular events. Biomechanical stress plays an important role in progression and rupture of atherosclerotic plaques. In recent years, non-invasive coronary computed tomography angiography (CCTA) computational fluid dynamics (CFD) modeling has made it possible to acquire the corresponding biomechanical stress parameters. These coronary biomechanical stress parameters, especially wall shear stress (WSS), will aid in the development of a more accurate clinical model for predicting plaque progression and major adverse cardiovascular events ( MACE ). In this review, the biomechanical stress and the role of WSS from CCTA in atherosclerosis were introduced, and the researches on the relationship between biomechanical stress from CCTA and coronary artery diseases were discussed.

Analysis of the Inhibitory Effect of Tirofiban on Shear-Induced Platelet Aggregation by Microfluidic Technique / 医用生物力学

Objective To observe the inhibitory effect of Tirofiban on different shear-induced platelet aggregation, and to provide medication suggestions for the treatment of thrombosis in different hemodynamic environment. Methods Polydimethylsiloxane ( PDMS)-glass microchannel chips were fabricated by soft lithography. The whole blood of healthy volunteers anticoagulated with sodium citrate was collected and incubated with different concentrations of Tirofiban in vitro. The blood flowed through the straight microchannel or channel with 80% narrow for 150 seconds at the speed of 11 μL/ min and 52 μL/ min, respectively. The wall shear stress rates in straight channel at 11 μL/ min and 52 μL/ min were 300 s-1 and 1 500 s-1, respectively. The maximum wall shear rates in the channel with 80% occlusion at 11 μL/ min and 52 μL/ min were 1 600 s-1 and 7 500 s-1, respectively. The adhesion and aggregation images of fluorescent labeled platelets on glass surface were photographed with the microscope, and the fluorescent images were analyzed with Image J. The platelet surface coverage ratio was used as a quantitative index of platelet aggregation behavior, and the IC50 of Tirofiban for platelet inhibition was calculated under different shear rates. Flow cytometry was used to detect the platelet activation index (CD62P, PAC-1) in the whole blood at 52 μL/ min in channel with 80% occlusion. Results Tirofiban inhibited platelet aggregation in a dose-dependent manner, and the inhibitory effect was related to the shear rate. Under the shear rates of 11 μL/ min and 52 μL/ min, the aggregation was almost completely inhibited when the concentration in straight channel reached 100 nmol / L. When the concentration in channels with 80% occlusion reached 1 μmol / L, the aggregation was almost completely inhibited. IC50 values at 11 μL/ min and 52 μL/ min in straight channel were 2. 3 nmol / L and 0. 5 nmol / L, respectively. IC50 values at 11 μL/ min and 52 μL/ min in channels with 80% occlusion were 20. 73 nmol / L and 4. 5 nmol / L. Pathologically high shearforce induced an increase in platelet activation, which could be inhibited by Tirofiban. Conclusions Tirofiban can effectively inhibit shear-induced platelet aggregation, and different concentrations of Tirofiban should be given according to the thrombus formed in different shear force environment in clinic practice

Mir-199a-3p Mediates Fluid Shear Stress-Induced Osteoblast Proliferation by Targeting CABLES-1 / 医用生物力学

Objective To explore the role of miR-199a-3p in osteoblast proliferation induced by fluid shear stress (FSS) and the potential molecular mechanism. Methods Osteoblast MC3T3-E1 was treated with 1. 2 Pa FSS with time gradients of 0, 15, 30, 45, 60, 75 and 90 min, respectively. MC3T3-E1 cells were transfected with miR-199a-3p mimic or miR-199a-3p inhibitor. MC3T3-E1 cells were transfected with miR-199a-3p mimic and itsnegative control and then treated with 1. 2 Pa FSS for 45 min. The pc DNA NC, pc DNA-CABLES -1, si RNA NC and si RNA CABLES-1 were transfected into MC3T3-E1 cells. The pc DNA-CABLES-1 and mir-199a-3p mimic and SI NA-cables-1 and miR-199a-3p inhibitor were co-transfected, respectively. Cell activity was detected by CCK-8 assay. Real-time quantitative PCR (RT-qPCR) was used to detect expression levels of CABLES-1, miR-199a-3p, CDK 6, Cyclin D1 and PCNA. Luciferase reporting assay was used to detect targeting relationship between CABLES-1 and miR-199a-3p. Immunofluorescence was used to detect protein expression of CABLES-1.Western blot was used to detect protein expression of CABLES-1, CDK 6, PCNA and Cyclin D1. Results Mir- 199a-3p in MC3T3-E1 cells was significantly down-regulated by FSS. Over-expressed miR-199a-3p inhibitedosteoblast proliferation, and down-regulated miR-199a-3p expression promoted osteoblast proliferation. miR-199a- 3p could reverse the FSS-induced proliferation in osteoblasts. Dual luciferase assay showed that miR-199a-3p targeted to CABLES-1 and over-expressed miR-199a-3p inhibited expression of CBALES-1 protein. CABLES-1 could promote proliferation of osteoblasts. miR-199a-3p inhibited osteoblast proliferation induced by FSS through CABLES-1. Conclusions FSS-induced osteoblast proliferation can be realized by down-regulated miR-199a-3p expression via targeting CABLES-1. The findings in this study provide new direction for researches on mechanism of FSS-induced osteoblast proliferation, as well as new ideas for future research on clinical application of mechanical loading in the treatment of bone and joint diseases.

CD44-HA Mediate Adhesion of MDA-MB-231 Cells and HL60 Cells under Fluid Shear Flow / 医用生物力学

Objective To explore how hyaluronic acid ( HA) in extracellular matrix regulates the adhesion ofCD44+tumor cells. Methods MDA-MB-231 cells or HL60 cells were perfused in a parallel plate chamber. Themovement of cells over immobilized HA was observed and analyzed to obtain the characteristics of cell adhesionand rolling. Results The adhesion number of MDA-MB-231 cells on HA substrate was positively regulated by HAconcentration, but not by HA molecular weight. Compared with physically adsorbed HA, immobilized HA byavidin-biotin could significantly improve the cell adhesion ratio. With the increase of shear stress in the range of30-50 mPa, the rolling velocity of cells increased and the adhesion ratio decreased, but the tether lifetime of cellswas not affected. In the same flow field, compared with MDA-MB-231 cells, HL60 cells with low expression ofCD44 rolled more quickly on immobilized HA, with shorter tether lifetime and much lower adhesion ratio(<1. 5% ). Conclusions Fluid shear stress might mediate the rolling velocity of MDA-MB-231 cells by regulatingthe CD44-HA association rate rather than their dissociation rate. The interaction between CD44 and HA is involved in the initial adhesion of HL60 cells, but it does not play a major role. This study will provide references for the design of anti-tumor drugs.

Fluid-Structure Interaction Simulation of Carotid Plaque / 医用生物力学

Objective To propose a two-way fluid-structure interaction (FSI) method based on real patients with carotid artery stenosis, and analyze the hemodynamic parameters of carotid plaques with different types at the lesion as well as deformation and stress changes of the plaque itself. Methods Three-dimensional ( 3D) modeling was performed based on computed tomography angiography ( CTA) data of patients with moderate carotid artery stenosis. The carotid artery wall model and plaque model were separated, and transient fluid structure coupling calculation was performed. The situation from early stage of carotid atherosclerosis to formation of the plaque was simulated. The plaque types were divided into thickened plaques, lipid plaques, mixed plaques and calcified plaques, among which thickened plaques were regarded as non-plaque conditions for representing the thickening of vascular intima-media. The stenotic carotid arteries with different plaque types were compared and analyzed. Results The plaques with different types had little effect on the overall blood flow, but the wall shear stress of lipid plaques at the lesion was lower than that of other plaques. With thickened plaques as a control, concurrence of the plaque would inhibit artery expansion, and lipid plaques were the most obvious. Calcified plaques had the highest average plaque structure stress, while lipid plaques had the lowest average plaque structure stress. Conclusions The method proposed in this study can analyze fluid area and solid area at the same time. The results can contribute to better understanding the influence of different plaque types on carotid artery diseases.

Establishment of large animal model of bicuspid aortic valve / 中国胸心血管外科临床杂志

@#Objective    To discuss the feasibility of establishment of animal model of "functional" bicuspid aortic valve with swine and observe its effect on the wall shear stress inside the aorta. Methods    Four common Shanghai White Swine with body weight between 50 kg to 55 kg were selected. Under general anesthesia and cardiopulmonary bypass, the aortic transverse incision approach was used, continuous suture with 6-0 polypropylene to align the left and right coronary valve leaflets to create a bicuspid valve morphology. After the operation, echocardiography was used to observe the aortic valve morphology and the hemodynamic changes of the aortic valve orifice. The effect on the wall shear stress inside the aorta was studied with 4D-Flow magnetic resonance imaging (MRI). Results    A total of 4 swine "functional" bicuspid aortic valve models were established, with a success rate of 100.0%. Echocardiography showed that the blood flow velocity of the aortic valve orifice was faster than that before the operation (0.96 m/s vs. 1.80 m/s). 4D-Flow MRI showed abnormally increased wall shear stress and blood flow velocity in the aorta of the animal models. After the surgery, in model animals, the maximal wall shear stress inside the ascending aorta was greater than 1.36 Pa, and the maximum blood flow velocity was greater than 1.4 m/s. Conclusion    Establishment of the animal model of "functional" bicuspid aortic valve in swine is feasible, scientific and reliable. It can be used in researches on evaluating the pathophysiological changes.

VWF Damage Based on Novel Maglev Taylor-Couette Blood-Shearing Circulation Platform / 医用生物力学

Objective To study von Willebrand factor(VWF) damage based on a novel Maglev Taylor-Couette blood-shearing device. Methods The magnetic levitation (maglev) Taylor-Couette blood-shearing device was designed, and the blood-shearing platform was built. Fresh porcine blood was tested in circulation loop for 1 hour at laminar flow state. VWF damage was assessed by analyzing sample through Western blot and enzyme-linked immunosorbent assay. Results With the increase of exposure time and shear stress, a large number of high molecular weight VWF multimers were degraded into low molecular weight VWF. The maximum rate of degradation was 569%. When the shear stress increased from 18 Pa to 55 Pa, the ratio of VWF-Rco to VWF-Ag decreased from 45.7% to 32.8%. ConclusionsCompared with initial sample, the VWF damage was mainly manifested by the decrease of high molecular weight VWF and the decrease of VWF activity, and VWF-Ag did not change significantly. The novel maglev Taylor-Couette blood-shearing device can quantitatively control the flow parameters (exposure time and shear stress), and be used for blood damage research in vitro, thus providing references for the design and optimization of extracorporeal membrane oxygenation and blood pump.

Biomechanical Environment Regulates Biomimetic Mineralization of Bone Matrix / 医用生物力学

Bone defects have always been an important cause of threat to human health, and artificial biomimetic bone repair replacement materials are currently one of the most effective and feasible solution approaches to treat bone damage. To develop artificial bone biomimetic materials, an in vitro biomimetic mineralization system must be constructed first to study in vitro biomimetic mineralization mechanism of natural bone matrix. Collagen is a template for mineralization, and its properties such as crosslinking degree, diameter, osmotic pressure, and surface charge can all directly affect mineralization progress. The biochemical and mechanical environments in which mineralization occurs are also quite distinct in their effects on mineralization process, particularly noncollagenous proteins and fluid shear stress (FSS). FSS is considered to be the main mechanical stimulation of bone tissues in micro-environment, which is of great significance to bone growth, repair and health maintenance. FSS at different levels and loading regimes has significant effects on transformation of amorphous calcium phosphate to bone apatite, self-assembly and directional alignment of collagen fibrils, and formation of hierarchical intrafibrillar mineralization. In this paper, the factors affecting collagen mineralization and their mechanism were summarized, with focus on regulation of FSS on collagen mineralization, and development direction in future was also prospected.

Correlation between vascular wall shear stress and stenosis degree and plaque characteristics in patients with atherosclerotic stenosis in the middle brain / 中华神经科杂志

Objective:To investigate the relationship between wall shear stress (WSS) and the degree of lumen stenosis and plaque characteristics in patients with atherosclerotic stenosis in the middle brain.Methods:Thirty-four patients with moderate to severe unilateral middle cerebral artery stenosis in Nanjing First Hospital from June 2020 to June 2021 were analyzed retrospectively. All patients underwent routine magnetic resonance imaging and vascular wall imaging to obtain plaque parameters such as plaque area, remodeling mode and remodeling index. Based on magnetic resonance angiography, a computational fluid dynamics model was established to simulate the local hemodynamics near the lesion and quantify WSS. The patients were divided into high WSS group and low WSS group according to the median WSS. The differences of clinical baseline data, degree of lumen stenosis and plaque characteristics between the two groups were compared. Pearson correlation analysis was used to calculate the correlation between WSS and lumen stenosis and plaque characteristics.Results:A total of 34 patients were included in this study, 17 in the high WSS group and 17 in the low WSS group. Compared with the low WSS group, the plasma homocysteine level in the high WSS group was lower [(11.10±4.96) μmol/L vs (16.97±6.98) μmol/L, t=-2.83, P=0.010], the degree of stenosis was lower (0.56±0.05 vs 0.66±0.08, t=-4.54, P<0.001), and the proportion of positive lumen remodeling was higher (12/17 vs 4/17, P=0.015). Pearson correlation analysis showed that the degree of lumen stenosis was negatively correlated with WSS ( r=-0.44, P=0.011), and the plaque area was not correlated with WSS. Conclusions:WSS in middle cerebral artery stenosis is related to the degree of lumen stenosis and the mode of vascular remodeling. Higher WSS has poor stability, but lower WSS is more likely to cause lumen stenosis.

Influence of bionic texture coronary stent on hemodynamics after implantation / 生物医学工程学杂志

To explore the influence of bionic texture coronary stents on hemodynamics, a type of bioabsorbable polylactic acid coronary stents was designed, for which a finite element analysis method was used to carry out simulation analysis on blood flow field after the implantation of bionic texture stents with three different shapes (rectangle, triangle and trapezoid), thus revealing the influence of groove shape and size on hemodynamics, and identifying the optimal solution of bionic texture groove. The results showed that the influence of bionic texture grooves of different shapes and sizes on the lower wall shear stress region had a certain regularity. Specifically, the improvement effect of grooves above 0.06 mm on blood flow characteristics was poor, and the effect of grooves below 0.06 mm was good. Furthermore, the smaller the size is, the better the improvement effect is, and the 0.02 mm triangular groove had the best improvement effect. Based on the results of this study, it is expected that bionic texture stents have provided a new method for reducing in-stent restenosis.

Effect of Danggui Buxuetang on Functional Activity of Endothelial Progenitor Cells Exposed to Shear Stress / 中国实验方剂学杂志

Objective:To investigate the effect of Danggui Buxuetang（DGBX）on the functional activity of rat endothelial progenitor cells（EPCs）exposed to different luminar shear stress （SS）. Method:EPCs isolated from rat bone marrow were incubated on a parallel plate flow chamber at a steady SS of 0， 0.12， 1.2， 2.4 Pa for 6 h，then the cells exposed to different SS were randomly divided into 8 groups： control group （perfused with serum free medium），simvastatin group（0.1 μmol·L^-1simvastatin），3 DGBX groups（low，medium，high-dose DGBX）and 3 inhibitor groups（3 DGBX groups with LY294002）. After 12 h，the samples were collected for the detection of cell proliferation ，migration，tubule formation ，the secretion of nitric oxide （NO） ，and the expressions of endothelial nitric oxide synthase（eNOS） mRNA and protein kinase B（Akt），respectively. Result:Compared with the control group，simvastatin and DGBX（high-dose）could both promote the functional activities and NO secretion，and up-regulate the expressions of eNOS mRNA and Akt protein in EPCs exposed to different SS（<italic>P</italic><0.05），while DGBX（mid-dose）could do these only at 0 Pa. However，LY294002 could inhibit all effects of DGBX on EPCs. Conclusion:SS seems to play an important role in the effect of DGBX on EPCs，and DGBX could promote the functional activity of EPCs exposed to SS by up-regulating the expressions of NO/eNOS/Akt.

Effect of Fluid Sheer Stress on Atherosclerosis and Progress of Research on Treatment of Sheer Stress Injury with Traditional Chinese Medicine： A Review / 中国实验方剂学杂志

Cells in the arterial wall are constantly subjected to the shear stress generated by the blood flow. Shear stress plays a pivotal role in the formation of atherosclerosis. The endothelial cells located between the blood and the vessel wall have a unique response to the shear stress of the blood flow， which can convert mechanical stimulation into intracellular signals， thereby affecting the pathological process of atherosclerosis. Endothelial function is not only regulated by hormones， growth factors and other biochemical substances， but also affected by mechanical forces such as blood flow shear stress. Physiologically， shear stress can play an anti-atherosclerotic role in maintaining the homeostasis of endothelial cells. Pathological shear stress will lead to endothelial dysfunction and promote the progression of atherosclerosis. Under the mediation of different shear stress， the endothelial function can be regulated through epigenetic pathways or mechanically sensitive cation channels. Therefore， it is necessary to understand how various signal transduction pathways are affected by pathological shear stress， so as to cause endothelial dysfunction and atherosclerosis. Traditional Chinese medicine（TCM） has been increasingly recognized for its curative effect in treating atherosclerosis， with the advantages of few side effects， multiple targets and multiple mechanisms. In recent years， the understanding of the anti-atherosclerosis mechanism of TCM mediated by shear stress has gradually deepened. This review will take endothelial function as the breakthrough point， systematically sort out the influence of shear stress on the pathological process of atherosclerosis and the related molecular mechanisms. Meanwhile， it is the first time to summarize the latest research progress of Chinese medicine against shear stress damage by sorting out the existing literature. This article mainly clarify the relationship between shear stress， endothelial function， atherosclerosis and TCM， in order to provide a theoretical basis for the clinical treatment and pathological mechanism of atherosclerosis.

Evaluation on Mechanical Damage of vWF Induced by Shear Stress in BPX-80 Centrifugal Blood Pump / 医用生物力学

Objective To evaluate the damage of von Willebrand factor (vWF) induced by shear stress in BPX-80 centrifugal blood pump, and determine whether it can be used as a reference pump for vWF damage research. Methods An in vitro hemolysis test platform was established according to the ASTM standards. The BPX-80 centrifugal blood pump was tested for 8 hours by using fresh porcine blood. The hemolysis level and vWF damage of hourly blood samples were then evaluated and compared with the static control group. ResultsThe hemolysis index of BPX-80 was stable and low during the test; vWF polymer with high molecular weight had a small amount of degradation, and showed no significant difference compared with the static control group; there was no significant change in the concentration of vWF antigen, which was basically consistent with the trend of the static control group. Conclusions BPX-80 centrifugal blood pump has good blood compatibility and can be used as the reference pump for vWF damage and hemolysis evaluation, thereby providing guidance for the design and optimization of new blood pumps.

The Influence of Skull Thickness on Intracranial Biomechanical Response / 医用生物力学

Objective To study the influence of skull thickness on intracranial biomechanical parameters by finite element method. Methods The female head at 5th percentile was selected for CT scanning to construct finite element model of the head with high biofidelity,and the model was verified by reconstructed cadaver test. The finite element model of the head with different skull thickness was established, and multiple groups of tests were carried out to compare the intracranial mechanical parameters. Results The negative value of intracranial pressure was significantly affected by the decrease in skull thickness under the same head size, while the negative value of intracranial pressure was slightly affected, with an increasing trend. The shear stress and von Mises stress of brain tissues were significantly increased with skull thickness increasing. Conclusions Under the same head size, the skull thickness will affect head injury to a certain extent, and people with small skull thickness are more likely to be injured than those with large skull thickness.

Effect of electroacupuncture on choroidal blood flow and the expression of endothelin-1 and its receptor in lens-induced myopic guinea pigs / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To observe the changes of the vessel density of choriocapillaris in lens-induced myopia in guinea pigs, and to explore choroidal endothelin-1(ET-1), endothelin receptor A(ETAR)and receptor B(ETBR)expression changes and the effect of electroacupuncture. <p>METHODS: Fifty-four guinea pigs were randomly divided into normal control(NC), lens-induced myopia(LIM)and LIM+electroacupuncture(LIM+EA). The NC group was fed normally without intervention and the right eye in LIM group and LIM+EA group was coverd with a -6.00D lens to establish a myopia model. At 2 and 4wk, the refraction, axial length and the vessel density of choriocapillaris in groups were measured. The expression and protein content of ET-1, ETAR and ETBR mRNA in groups were detected by the real-time fluorescent quantitative PCR(quantitative polymerase chain reaction, q-PCR), enzyme-linked immunosorbent assay(ELISA)and immunohistochemistry. <p>RESULTS: At 2 and 4wk, compared with the the NC group, refraction and axial length in LIM group and LIM+EA group had significantly increased(all <i>P</i><0.001). Compared with the LIM group, the refraction and axial length in LIM+EA group were decreased(all <i>P</i><0.05). At 2 and 4wk, compared with the NC group,the vessel density of choriocapillaris was decreased(<i>P</i><0.001)and the ET-1, ETAR and ETBR mRNA and protein levels in choroid were increased(all <i>P</i><0.05)in LIM group. At 2 and 4wk, compared with the LIM group,the vessel density of choriocapillaris was decreased(<i>P</i><0.01)and the ET-1, ETAR and ETBR mRNA and protein levels in choroid were increased in LIM+EA group.<p>CONCLUSION:In LIM guinea pigs, the choroidal blood flow decreased with the increased of refraction and axial length, which may affect ET-1 and its receptors through vascular shear force during the development of myopia. At the same time, electroacupuncture can improve choroidal blood flow through neuromodulation and affects the vascular shear stress to down-regulate the content of ET-1 and its receptor to delay the development of myopia.

Chemokine CXCL12-Induced Calcium Response of Jurkat T Cells under Fluid Shear Stress / 医用生物力学

Objective To investigate the mechanism of mechano-chemical coregulation in chemokine-induced calcium response of Jurkat T cells under fluid shear stress (FSS). Methods By using parallel-plate flow chamber combined with fluorescence microscope, the calcium response of Jurkat T cells on CXCL12 was observed to extract the corresponding characteristic parameters under static or flow state, with or without extracellular Ca2+, respectively. Results Immobilized CXCL12 could induce firm adhesion of the circulating Jurkat T cells, and the arrested cells increased with the increase of CXCL12 concentration. Force could trigger the calcium response of Jurkat T cells and sharply raised the activation ratio from 4% up to 75% when the FSS increased from 0 to 20 mPa. Under 20 mPa FSS, extracellular Ca2+ could stimulate quickly the calcium response by shortening the delay time (about 23 s), and enhance calcium intensity by prolonging the climbing time (about 7 s) and half time (about 20 s). Conclusions The cooperation between FSS and extracellular Ca2+ would accelerate and enhance CXCL12-mediated-calcium response of Jurkat T cells, which indicated a fast mechanosensitive pathway through ‘extracellular calcium influx-intracellular calcium store release’. The research results would contribute to understanding the process of T cells activation and providing the clue for relevant pathological and drug research.

Hemodynamic Analysis on Anomalous Origin of the Right Coronary Artery from the Left Coronary Artery Sinus / 医用生物力学

Objective To analyze the hemodynamic parameters of anomalous origin of the right coronary artery from the left coronary artery sinus (AORL) based on computational fluid dynamics (CFD), so as to make an evaluation of the disease. Methods A normal right coronary artery (RCA) case and an AORL case were selected. Two models were reconstructed in Mimics software and imported into ANSYS CFX software for hemodynamics simulation. The hemodynamics of normal RCA model and AORL model were compared. Results AORL model had a smaller volume flow (9.35 cm3/s), which might lead to insufficient blood supply downstream of the RCA; the pressure at the acute corner of AORL model (13.78 kPa) was lower than normal RCA model (14.9 kPa); the wall shear stress (WSS) of AORL model (12.83 Pa) was larger than that of normal RCA model (9.74 Pa); the total deformation of AORL model was relatively large. Conclusions The entrance velocity and pressure of AORL were lower than those of normal RCA, which might lead to ischemic symptoms. The research findings are of theoretical significance for the effective evaluation of ischemia and other diseases in clinic.

Hemodynamic Characteristics of Pulmonary Arterial Hypertension Related to Congenital Heart Disease / 医用生物力学

Objective Hemodynamic disorder of the pulmonary artery (PA) is the main cause of pulmonary arterial hypertension related to congenital heart disease (PAH-CHD). To study the hemodynamic characteristics of PA, so as to understand biomechanical factors in the occurrence and development of PAH-CHD. Methods Clinical and imaging data were collected in five PAH-CHD patients and five matched controls (Non-PAH) to reconstruct subject-specific three-dimensional (3D) PA models. Computational fluid dynamics (CFD) was performed to compare the hemodynamic difference of flow patterns, wall shear stress (WSS) and normalized energy loss (E·) in the two groups. Results Hemodynamics-related parameters showed that the velocity and WSS were higher in the left and right PA branches of PAH-CHD patients, with significantly lower WSS in the main PA. The E· significantly increased in PAH-CHD patients and positively correlated with normalized PA diameter and inflow. Conclusions Compared with Non-PAH subjects, PAH-CHD patients have obviously higher velocity and WSS in PA branches, lower WSS in main PA and greater E·, indicating these hemodynamic parameters are related with the PAH-CHD, which can be used as potential biomechanical factors for the clinical evaluation of PAH-CHD.

On shear-induced platelet aggregation and its therapy / 药学学报

It is now widely accepted that platelet aggregation plays an important role in physiological hemostasis and pathological thrombosis associated with cardiovascular and cerebrovascular diseases. Anti-platelet aggregation drug research is also a hot spot of current research. The biggest challenge of antiplatelet therapy has been the molecular overlap of the hemostasis and thrombosis, leading to a serious risk of bleeding. Recent studies have emphasized the importance of shear stress generated from blood flow, which will primarily drive platelet activation and aggregation in thrombosis. So if we can take advantage of the differences between the physiological and pathological vascular blood flow environment, the development of selective anti-platelet therapy may be a safer treatment for cardiovascular and cerebrovascular diseases. In this review, we discuss the underlying mechanisms of shear-induced platelet activation. Later, we summarize the effects and mechanisms of compounds and traditional Chinese medicine on shear-induced platelet activation. The aim is to provide a reference for the study of biological pharmacology of traditional Chinese medicine for promoting blood circulation and removing blood stasis.