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1.
Front Physiol ; 15: 1386650, 2024.
Article in English | MEDLINE | ID: mdl-38983719

ABSTRACT

Background: The increasing popularity of hypoxic training as a training method to improve physical performance indicates the need to study the effects of this type of intervention on blood morphological and rheological indices, since the adaptive changes that follow such training mainly affect blood indices. In this study, the effects of a 4 weeks of intermittent hypoxic training on blood morphological and rheological indicators in physically active men were assessed. Methods: Forty-eight young, physically active men, participated in the study. Participants were randomly divided into three groups: two training groups and a control group without intervention (CTRL). Each group consisted of 16 participants. Training groups performed interval training (three times per week, 4 weeks, 12 workouts) under different conditions: in hypoxia (IHT; fraction of inspired oxygen (FiO2) = 14.4%) or in normoxia (NT; FiO2 = 20.9%). The control group performed only two workouts 4 weeks apart. Blood was taken during the first and last training session at rest, and 3 minutes after training. Results: After the last training session, there was a significant increase in mean corpuscular volume and a decrease in mean corpuscular haemoglobin concentration measured at rest only in the IHT group. There was also a significant decrease in resting aggregation amplitude for the IHT and CTRL groups. There was no difference in change of post-exercise plasma volume between first and last training session. Conclusion: The applied intermittent interval training in conditions of normoxia and hypoxia had no significant impact on resting aggregation parameters. This suggest that training under hypoxic conditions does not cause adverse rheological changes.

2.
Sci Rep ; 14(1): 8554, 2024 04 12.
Article in English | MEDLINE | ID: mdl-38609397

ABSTRACT

Cold water immersion (CWI) involves rapid cooling of the body, which, in healthy individuals, triggers a defence response to an extreme stimulus, to which the body reacts with stress. The aim of the study was to determine the effect of CWI on hemorheological blood indicators. The study group consisted of 13 young males. Blood samples were collected before and after CWI. The assessed parameters included the complete blood count, fibrinogen, hs-C-reactive protein (CRP), proteinogram, and blood rheology factors, such as erythrocyte elongation index (EI), half-time of total aggregation, and aggregation index. Additionally, the effect of reduced temperature on primary human vascular endothelium was investigated in vitro. CWI resulted in the decrease of body temperature to 31.55 ± 2.87 °C. After CWI, neutrophil count and mean corpuscular volume (MCV) were significantly increased in the study group, while lymphocyte count was significantly decreased. Significantly higher levels of total blood protein and albumin concentration were detected after the immersion. Among hemorheological characteristics, erythrocyte EIs at shear stress values ranging from 2.19 to 60.30 Pa were significantly lower after CWI. No significant changes in other rheological, morphological or biochemical parameters were observed. In vitro, human umbilical vein endothelial cells responded to 3 h of temperature decrease to 25 °C with unchanged viability, but increased recruitment of THP-1 monocytic cells and changes in cell morphology were observed. This was the first study to evaluate the effect of single CWI on rheological properties of blood in healthy young men. The results indicate that a single CWI may increase blood protein concentrations and worsen erythrocyte deformability parameters.


Subject(s)
Hemorheology , Immersion , Male , Humans , Leukocyte Count , C-Reactive Protein , Human Umbilical Vein Endothelial Cells
3.
Biorheology ; 59(3-4): 63-80, 2024.
Article in English | MEDLINE | ID: mdl-38461497

ABSTRACT

Leukocytes and platelets must adhere to the wall of blood vessels to carry out their protective functions in inflammation and haemostasis. Recruitment is critically dependent on rheological variables (wall shear rate and stress, red cell aggregation and haematocrit) which affect delivery to the vessel wall as well as velocities and forces experienced there. Leukocyte recruitment is efficient only up to wall shear rates of about 300 s-1 and usually restricted to low-shear post-capillary venules in inflammation. Being smaller, platelets experience lower velocities and shear forces adjacent to the wall and can adhere at much higher shear rates for haemostasis in arteries. In addition, we found quite different effects of variations in haematocrit or red cell aggregation on attachment of neutrophils or platelets, which also assist their separate recruitment in venules or arteries. However, it has become increasingly evident that inflammatory and thrombotic responses may occur together, with platelets promoting the adhesion and activation of neutrophils and monocytes. Indeed, it is 30 years since we demonstrated that platelets could cause neutrophils to aggregate in suspension and, when attached to a surface, could support selectin-mediated rolling of all leukocytes. Thrombin-activated platelets could further induce neutrophil activation and immobilisation. In some conditions, platelets could bind to intact endothelial monolayers and capture neutrophils or monocytes. Subsequently, we found that extracellular vesicles released by activated platelets (PEV) fulfilled similar functions when deposited on surfaces or bound to endothelial cells. In murine models, platelets or PEV could act as bridges for monocytes in inflamed vessels. Thus, leukocytes and platelets are rheologically adapted for their separate functions, while novel thrombo-inflammatory pathways using platelets or PEV may underlie pathogenic leukocyte recruitment.


Subject(s)
Erythrocyte Aggregation , Platelet Adhesiveness , Humans , Animals , Mice , Platelet Adhesiveness/physiology , Endothelial Cells , Blood Platelets/physiology , Leukocytes/physiology , Neutrophils , Rheology , Inflammation/metabolism , Cell Adhesion , P-Selectin/metabolism
4.
Sci Rep ; 14(1): 4260, 2024 02 21.
Article in English | MEDLINE | ID: mdl-38383860

ABSTRACT

Multiple myeloma (MM) is considered to be one of the hematological malignancies formed by excessive and abnormal proliferation of plasmocytes. Among other parameters, several blood tests are used to diagnose multiple myeloma. The hemorheological profile in multiple myeloma is not widely studied. Hemorheology includes the study of measuring the deformability and aggregation of erythrocytes, blood viscosity, and sedimentation rate. The degree of deformability of blood cells is necessary to maintain proper vital functions. Proper deformability of red blood cells ensures proper blood circulation, tissue oxidation and carbon dioxide uptake. The aim of the study was to compare morphology and blood rheology parameters in patients with MM and healthy individuals. The study included 33 patients with MM, and 33 healthy subjects of the same age. The hematological blood parameters were evaluated using ABX MICROS 60 hematology analyzer. The LORCA Analyzer to study erythrocyte aggregation and deformability. Patients with MM had lower red blood cells count (RBC) (9.11%) (p < 0.001) and half time of total aggregation (T1/2) (94.29%) (p < 0.001) values and higher mean corpuscular volume (MCV) (5.50%) (p < 0.001), aggregation index (AI) (68.60%) (p < 0.001), total extent of aggregation (AMP) (87.92%) (p < 0.001) values than the healthy control group. Aggregation in patients with MM is different compared to healthy individuals. It was observed that the percentage of cell aggregation is almost 50% higher than in the control group. The study of morphology, aggregation and deformability of erythrocytes in patients with suspected MM may be helpful in making clinical decisions.


Subject(s)
Erythrocyte Deformability , Multiple Myeloma , Humans , Hemorheology , Erythrocytes , Erythrocyte Aggregation , Rheology , Blood Viscosity , Blood Sedimentation
5.
Rev Med Interne ; 44(4S1): 4S18-4S23, 2023 Nov.
Article in French | MEDLINE | ID: mdl-38049242

ABSTRACT

Sickle cell anemia is a genetic disorder that affects hemoglobin leading to the production of an abnormal hemoglobin, called HbS. HbS has the property to polymerize under deoxygenated conditions, causing a mechanical distortion of red blood cells; a phenomenon called sickling. These sickle red blood cells are more fragile and rigid, leading to chronic hemolytic anemia and painful vaso-occlusive crises, as well as chronic vascular complications that can affect many organs. The abnormal functional properties of these sickle red blood cells are responsible for a wide range of clinical expression of the disease. HbS polymerization can be influenced by many factors, such as the hydration state of the red blood cells or the affinity of hemoglobin for oxygen. Moreover, the rheological characteristics of red blood cells, including their deformability and aggregation properties, are associated with specific clinical phenotypes. The pro-inflammatory and pro-oxidant state, as well as the repeated polymerization of HbS, accelerate the senescence of sickle red blood cells, promoting the release of microparticles and contributing to vascular dysfunction. Patients' red blood cells also have molecular characteristics that promote their adhesion to the endothelium and other circulating cells, contributing to the onset of vascular complications. Massive intravascular hemolysis, due to increased erythrocyte fragility, is also responsible for chronic vascular complications. These different alterations are privileged therapeutic targets, leading to the emergence of new specific treatments. © 2023 Société nationale française de médecine interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.


Subject(s)
Anemia, Sickle Cell , Humans , Anemia, Sickle Cell/complications , Anemia, Sickle Cell/epidemiology , Anemia, Sickle Cell/therapy , Hemolysis , Erythrocytes, Abnormal/metabolism , Oxygen , Hemoglobins/metabolism
6.
Presse Med ; 52(4): 104202, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37944640

ABSTRACT

Sickle cell disease (SCD) is an hereditary disorder characterized by the production of an abnormal hemoglobin called hemoglobin S (HbS). HbS may polymerize in deoxygenated conditions, which leads to red blood cell (RBC) sickling. Sickled RBCs are more rigid and fragile, and prone to lysis. SCD patients exhibit various acute and/or chronic complications, which may affect several organs. The clinical presentation of SCD is highly variable from one patient to another and cannot be only explained by RBC sickling. Increased blood viscosity, caused by the presence of RBCs with abnormal deformability and aggregation, may increase vascular resistance and increase the risk of acute and chronic vascular complications. Chronic hemolysis results in decreased nitric oxide (NO) bioavailability which may compromise vasodilation and participate to the development of chronic vasculopathy. Furthermore, chronic hemolysis is responsible for increased inflammation and oxidative stress, which affect the vascular system and may promote the adhesion of circulating cells to endothelial cells. Extracellular vesicles and especially RBC microparticles (massively released in the context of SCD) are also at the origin of vascular damages and increased white blood cells adhesion to the endothelium, which may trigger vaso-occlusive crisis and other vascular-related complications. This review highlights the fact that SCD should not only be considered as a hematological disorder but also as a vascular disease.


Subject(s)
Anemia, Sickle Cell , Vascular Diseases , Humans , Hemolysis , Endothelial Cells/metabolism , Anemia, Sickle Cell/complications , Anemia, Sickle Cell/metabolism , Hemoglobin, Sickle/metabolism , Vascular Diseases/complications
7.
Int J Mol Sci ; 24(19)2023 Oct 06.
Article in English | MEDLINE | ID: mdl-37834401

ABSTRACT

Several studies have indicated that COVID-19 can lead to alterations in blood rheology, including an increase in red blood cell aggregation. The precise mechanisms behind this phenomenon are not yet fully comprehended. The latest findings suggest that erythrocyte aggregation significantly influences microcirculation, causes the formation of blood clots in blood vessels, and even damages the endothelial glycocalyx, leading to endothelial dysfunction. The focus of this research lies in investigating the cellular factors influencing these changes in aggregation and discussing potential causes and implications in the context of COVID-19 pathophysiology. For this purpose, the aggregation of erythrocytes in a group of 52 patients with COVID-19 pneumonia was examined in a 70 kDa Dextran solution, which eliminates the influence of plasma factors. Using image analysis, the velocities and sizes of the formed aggregates were investigated, determining their porosity. This study showed that the process of erythrocyte aggregation in COVID-19 patients, independent of plasma factors, leads to the formation of more compact, denser, three-dimensional aggregates. These aggregates may be less likely to disperse under circulatory shear stress, increasing the risk of thrombotic events. This study also suggests that cellular aggregation factors can be responsible for the thrombotic disorders observed long after infection, even when plasma factors have normalized. The results and subsequent broad discussion presented in this study can contribute to a better understanding of the potential complications associated with increased erythrocyte aggregation.


Subject(s)
COVID-19 , Erythrocyte Aggregation , Humans , Dextrans , Erythrocytes/physiology , Plasma
8.
Stomatologiia (Mosk) ; 102(4): 22-26, 2023.
Article in Russian | MEDLINE | ID: mdl-37622296

ABSTRACT

THE AIM OF THE STUDY: To evaluate the change in the level of concentration of the antibacterial drug Vancomycin registered in the purulent focus area (facial vein) and in the peripheral blood flow (cubital vein) in patients with phlegmon of the maxillofacial region (MFR). MATERIALS AND METHODS: The clinical material of the study was 12 patients with phlegmon of MFR who were being treated in the maxillofacial department of the N.I. Pirogov State Clinical Hospital No. 1 of the Moscow Medical Center. The drainage of phlegmons was performed on the day of admission of the patient 2-3 days after the onset of the disease. The phlegmons involved two or more spaces of the MFR. As an antimicrobial drug, 500 mg of Vancomycin in 400 ml of saline solution was used intravenously. Quantitative registration of Vancomycin was carried out 2 hours after intravenous infusion. Blood sampling was carried out from the cubital and facial veins in an amount of 7-8 ml intraoperatively at the opening of the phlegmon, under endotracheal anesthesia. The concentration of the antibiotic was determined by high-performance liquid crystal chromatography. RESULTS AND DISCUSSION: The study found that the concentration of Vancomycin in the facial vein exceeds similar indicators obtained from the cubital vein. The difference in the percentage ratio averaged 19.2±7.3%. In 10 patients with phlegmons of various localization, it was found that the penetration of the antibacterial drug into the tissues of the inflammatory focus is higher compared to the periphery. However, in a number of patients, the concentration of the drug did not exceed the minimum suppressive concentration recommended for obtaining a therapeutic effect (for Vancomycin, it is at least 2 mcg / ml). CONCLUSION: To achieve the therapeutic effect of phlegmon treatment, it is necessary to select an individual dose of the drug for each patient.


Subject(s)
Drug Monitoring , Vancomycin , Humans , Cellulitis/drug therapy , Anti-Bacterial Agents , Head
9.
Biomech Model Mechanobiol ; 22(4): 1447-1457, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37389735

ABSTRACT

Hemodynamics play a vital role for the risk of thrombosis in the left atrial appendage (LAA) and left atrium (LA) for patients with atrial fibrillation. Accurate prediction of hemodynamics in the LA can provide important guidance for assessing the risk of thrombosis in the LAA. Patient specificity is a crucial factor in representing the true hemodynamic fields. In this study, we investigated the effects of blood rheology (as a function of hematocrit and shear rate), as well as patient-specific mitral valve (MV) boundary conditions (MV area and velocity profiles measured by ultrasound) on the hemodynamics and thrombosis potential of the LAA. Four scenarios were setup with different degrees of patient specificity. Though using a constant blood viscosity can classify the thrombus and non-thrombus patients for all the hemodynamic indicators, the risk of thrombosis was underestimated for all patients compared with patient-specific viscosities. The results with least patient specificities showed that patients prone to thrombosis predicted by three hemodynamic indicators were inconsistent with clinical observations. Moreover, though patients had the same MV inlet flow rate, different MV models lead to different trends in the risk of thrombosis in different patients. We also found that endothelial cell activation potential and relative residence time can effectively distinguish thrombus and non-thrombus patients for all the scenarios, relatively insensitive to patient specificities. Overall, the findings of this study provide useful insights on patients-specific hemodynamic simulations of the LA.


Subject(s)
Atrial Appendage , Atrial Fibrillation , Thrombosis , Humans , Mitral Valve , Blood Viscosity , Hemodynamics , Computer Simulation
10.
Biomech Model Mechanobiol ; 22(4): 1193-1207, 2023 Aug.
Article in English | MEDLINE | ID: mdl-36947349

ABSTRACT

One of the effective treatment options for intracranial aneurysms is stent-assisted coiling. Though, previous works have demonstrated that stent usage would result in the deformation of the local vasculature. The effect of simple stent on the blood hemodynamics is still uncertain. In this work, hemodynamic features of the blood stream on four different ICA aneurysm with/without interventional are investigated. To estimate the relative impacts of vessel deformation, four distinctive ICA aneurysm is simulated by the one-way FSI technique. Four hemodynamic factors of aneurysm blood velocity, wall pressure and WSS are compared in the peak systolic stage to disclose the impact of defamation by the stent in two conditions. The stent usage would decrease almost all of the mentioned parameters, except for OSI. Stenting reduces neck inflow rate, while the effect of interventional was not consistent among the aneurysms. The deformation of an aneurysm has a strong influence on the hemodynamics of an aneurysm. This outcome is ignored by most of the preceding investigations, which focused on the pre-interventional state for studying the relationship between hemodynamics and stents. Present results show that the application of stent without coiling would improve most hemodynamic factors, especially when the deformation of the aneurysm is high enough.


Subject(s)
Hemodynamics , Intracranial Aneurysm , Humans , Stents , Treatment Outcome
11.
Article in English | MEDLINE | ID: mdl-36982070

ABSTRACT

The aim of this study was to analyze the selected hematological and rheological indices in female rowers during the competitive season. The study included 10 female rowers (aged 21.2 ± 2.6) and the control group consisted of 10 woman of corresponding age (non-athletes). The examination of athletes took place two times: at the beginning of the season during high endurance low intensity training period in January (baseline) and at the end of the competitive season in October (after). Blood samples taken from all woman were analyzed for hematological and rheological parameters. The training period of rowers during the 10 months resulted in decrease in red blood cell count and RBC deformability, in contrast to an improvement in some rheological functions such a decrease in fibrinogen concentration, plasma viscosity and aggregation index. The training program practice in rowing modulated some hematological and rheological indices. Some of them positively influenced the cardiovascular system and reduced potential risks connected with hard training and dehydration, but others may have followed from overtraining or not enough relaxation time between training units.


Subject(s)
Endurance Training , Water Sports , Humans , Female , Rheology/methods , Athletes , Fibrinogen , Blood Viscosity
12.
Stomatologiia (Mosk) ; 102(1): 73-77, 2023.
Article in Russian | MEDLINE | ID: mdl-36800790

ABSTRACT

The article focuses on the clinical manifestation of inflammatory and destructive lesions of the bones of the midface, nose and paranasal sinuses as a long-term complication of COVID-19 with clinical examples provided.


Subject(s)
COVID-19 , Osteonecrosis , Humans , COVID-19/complications , Face , Necrosis , Facial Bones
13.
Int J Numer Method Biomed Eng ; 39(4): e3576, 2023 04.
Article in English | MEDLINE | ID: mdl-35099851

ABSTRACT

Computational hemodynamics has received increasing attention recently. Patient-specific simulations require questionable model assumptions, for example, for geometry, boundary conditions, and material parameters. Consequently, the credibility of these simulations is much doubted, and rightly so. Yet, the matter may be addressed by a rigorous uncertainty quantification. In this contribution, we investigated the impact of blood rheological models on wall shear stress uncertainties in aortic hemodynamics obtained in numerical simulations. Based on shear-rheometric experiments, we compare the non-Newtonian Carreau model to a simple Newtonian model and a Reynolds number-equivalent Newtonian model. Bayesian Probability Theory treats uncertainties consistently and allows to include elusive assumptions such as the comparability of flow regimes. We overcome the prohibitively high computational cost for the simulation with a surrogate model, and account for the uncertainties of the surrogate model itself, too. We have two main findings: (1) The Newtonian models mostly underestimate the uncertainties as compared to the non-Newtonian model. (2) The wall shear stresses of specific persons cannot be distinguished due to largely overlapping uncertainty bands, implying that a more precise determination of person-specific blood rheological properties is necessary for person-specific simulations. While we refrain from a general recommendation for one rheological model, we have quantified the error of the uncertainty quantification associated with these modeling choices.


Subject(s)
Aorta , Hemodynamics , Humans , Bayes Theorem , Uncertainty , Rheology , Stress, Mechanical , Models, Cardiovascular , Blood Flow Velocity , Computer Simulation
14.
Clin Hemorheol Microcirc ; 83(3): 279-286, 2023.
Article in English | MEDLINE | ID: mdl-36565109

ABSTRACT

OBJECTIVE: assessment of the effect of a series of 20 whole-body cryotherapy sessions on the morphological and rheological indicators of blood in healthy people. METHODS: The experimental group consisted of 15 women and 15 men who underwent a series of whole-body cryotherapy treatments. The control group consisted of 15 women and 15 men - without intervention. For the analysis of blood biochemical parameters, venous blood was collected twice: Study 1: on the day of the commencement of whole body cryotherapy / from the control group; and Study 2: after a series of 20 cryotherapy sessions / from the control group (4 weeks). RESULTS: After whole-body cryotherapy a statistically significant decrease in RBC, HGB, HCT, MCV, EI 0.30 and an increase in MCHC and EI 2.19-60.30 were observed in women, as well as a decrease in MCV, MCH, AI and an increase in PLT, EI 0.30-60.30, AMP, T1/2 in men. CONCLUSIONS: The use of whole-body cryotherapy causes changes in blood counts in various directions and has a positive effect on the rheological properties of blood in women and men - it increases the elongation index and reduces the aggregation index.


Subject(s)
Cryotherapy , Erythrocyte Deformability , Erythrocytes , Female , Humans , Male , Cryotherapy/adverse effects , Healthy Volunteers , Rheology
15.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-979470

ABSTRACT

With the improvement of people's living standards and the increasing aging population, the incidence of cardiovascular diseases has sharply risen, making it the leading cause of death and a major "killer" for humans. The prevention and treatment of cardiovascular diseases still face severe challenges. Shenmai injection (SMI), a Chinese medicinal preparation, is widely used in the prevention and treatment of cardiovascular diseases because of its individualized advantages in syndrome differentiation and definite efficacy. Meanwhile, its pharmacological effects and related mechanism are becoming increasingly clear. Modern research shows that SMI can exert cardioprotective effects by reducing myocardial inflammatory response, alleviating oxidative stress, inhibiting myocardial cell apoptosis, improving microcirculatory dysfunction after myocardial ischemia-reperfusion, protecting mitochondrial structure and function, inhibiting ventricular remodeling, reducing drug-induced cardiotoxicity, and possessing antiviral properties. Additionally, it can produce cardiovascular protection by relaxing blood vessels, protecting endothelial cells, and promoting angiogenesis. Furthermore, SMI can lower blood viscosity and lipid levels, thus improving blood rheology. In the future, more clinical trials and basic research are needed to clarify its therapeutic efficacy and target mechanism to further confirm the effectiveness and safety of its clinical application.

16.
Biology (Basel) ; 11(10)2022 Oct 15.
Article in English | MEDLINE | ID: mdl-36290417

ABSTRACT

The study assessed the effect of 3-week intermittent hypoxic training on blood biochemical indicators (blood morphology, fibrinogen), blood rheological properties (erythrocyte deformability, aggregation), erythrocyte enzymatic activity (acetylcholinesterase), and maximal oxygen uptake in competitive rowers. Fourteen male rowers were divided into two equal groups: experimental, training on ergometers under normobaric hypoxia (FiO2 = 16.0%), and control, training on ergometers under normoxia (FiO2 = 21%). Fasting blood was taken before and after training. A significant between-group difference in neutrophil levels before training was noted and a significant decrease in white blood cells in the hypoxia group. Both groups exhibited an increase in elongation index. In the normoxia group, a significant increase in erythrocyte aggregation amplitude was revealed. No significant changes occurred in the other biochemical indicators or those evaluating erythrocyte metabolic activity. Normobaric hypoxia increased erythrocyte deformability, improving blood rheological properties. Maximal oxygen uptake significantly increased only in the experimental group.

17.
Front Physiol ; 13: 993287, 2022.
Article in English | MEDLINE | ID: mdl-36117690
18.
Comput Methods Programs Biomed ; 219: 106757, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35338884

ABSTRACT

BACKGROUND AND OBJECTIVE: Treatment of intracranial aneurysms with flow-diverting stents prevents rupture by reducing blood flow and creating thrombosis within the aneurysm. This paper aims to assess the hemodynamic effect of placing stents with different struts (0, 3, 5, 7 struts) on intracranial aneurysms and to propose a simple prediction model of thrombosis zone without any further computational cost. METHOD: Lattice Boltzmann method with different rheological models (Newtonian, Carreau-Yasuda, KL) of blood are used to study the hemodynamic effect of flow-diverting stents in the aneurysm. Pulsatile flow boundary conditions were applied in the inlet of the artery. The average Reynolds number was resulting Re = 111. The Lagrangian tracking of the particle was developed to assess the intra-aneurysmal blood stagnation. To predict the probable thrombose zone induced by flow-diverting stents, the shear rate threshold is utilized to determine the nodes of fluid to clot. RESULTS: The results show that the flow patterns into the aneurysmal sac develop a vortex, decreasing after stent placement until disappearance for the stent with seven struts (porosity 71.4%). Velocity, shear rate, shear stress, trajectory, path length, and occlusion rate are compared before and after stent placement. These parameters decrease inversely with the porosity of the stent. The three models yield a closes result of the (velocity, shear rate, occlusion rate). Tracking the fluid-particle trajectory shows that the length of the particle paths decreases with the number of struts causing fluid to slow down and increase, consequently, the residence time into the sac. CONCLUSION: The flow-diverting stents placement cause the reduction of dynamic flow within aneurysm. The reduction effect is almost the same below five struts (80% of porosity). The results show that, if our objective is restricted to estimating the hemodynamic effect, measured by (velocity, shear rate, occlusion rate), the differences between rheological behavior models are, practically, not significant, and the models can be used indifferently.


Subject(s)
Intracranial Aneurysm , Thrombosis , Blood Flow Velocity , Hemodynamics/physiology , Humans , Intracranial Aneurysm/surgery , Rheology , Stents , Thrombosis/prevention & control
19.
Biomimetics (Basel) ; 7(1)2022 Jan 13.
Article in English | MEDLINE | ID: mdl-35076493

ABSTRACT

Diabetes mellitus, a metabolic disease characterized by chronically elevated blood glucose levels, affects about 29 million Americans and more than 422 million adults all over the world. Particularly, type 2 diabetes mellitus (T2DM) accounts for 90-95% of the cases of vascular disease and its prevalence is increasing due to the rising obesity rates in modern societies. Although multiple factors associated with diabetes, such as reduced red blood cell (RBC) deformability, enhanced RBC aggregation and adhesion to the endothelium, as well as elevated blood viscosity are thought to contribute to the hemodynamic impairment and vascular occlusion, clinical or experimental studies cannot directly quantify the contributions of these factors to the abnormal hematology in T2DM. Recently, computational modeling has been employed to dissect the impacts of the aberrant biomechanics of diabetic RBCs and their adverse effects on microcirculation. In this review, we summarize the recent advances in the developments and applications of computational models in investigating the abnormal properties of diabetic blood from the cellular level to the vascular level. We expect that this review will motivate and steer the development of new models in this area and shift the attention of the community from conventional laboratory studies to combined experimental and computational investigations, aiming to provide new inspirations for the development of advanced tools to improve our understanding of the pathogenesis and pathology of T2DM.

20.
Article in English | MEDLINE | ID: mdl-34303334

ABSTRACT

BACKGROUND: Insulin resistance is a well-known predictor and risk factor for type 2 diabetes mellitus (T2DM). Higher hematocrit induced by higher insulin resistance affects blood rheology. OBJECTIVE: This study intended to reveal the association between indices of insulin resistance and hemorheological parameters during a 75 g oral glucose tolerance test (75-g OGTT). METHODS: A total of 575 healthy young Japanese participants took 75-g OGTT. We then analyzed the association between insulin resistance indices and hematological parameters. RESULTS: The Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was significantly correlated with hematocrit (Ht), hemoglobin (Hb), red blood cell (RBC), white blood cell (WBC), platelet count, lipid parameters and body mass index (BMI). The Matsuda index was negatively correlated with RBC count, WBC count, platelet count, total cholesterol (TC), low-density lipoprotein- cholesterol (LDL-C), triglyceride (TG), and positively correlated with high-density lipoprotein- cholesterol (HDL-C). The disposition index was negatively correlated with Hb, RBC count, LDL-C and BMI, and positively correlated with HDL-C. The Homeostasis Model Assessment of beta cell (HOMA-ß) was positively correlated with WBC count, platelet count, TC, LDL-C and TG. The insulinogenic index was positively correlated with WBC count, platelet count and TC. Multiple regression analysis revealed that HOMA-IR was independently associated with TG, and the Matsuda index was independently associated with TG, WBC count, and platelet count. The insulinogenic index was independently associated with WBC count. CONCLUSION: Cardinal rheological parameters reflected insulin resistance and release even in young healthy Japanese individuals within the physiological range of glycemic control.


Subject(s)
Blood Circulation/physiology , Blood Glucose/metabolism , Insulin Resistance/physiology , Adult , Erythrocyte Count , Female , Glucose Tolerance Test , Healthy Volunteers , Hematocrit , Humans , Insulin Secretion/physiology , Japan , Leukocyte Count , Male , Platelet Count , Rheology , Young Adult
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