Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.645
Filtrar
1.
Biophys J ; 120(21): 4663-4671, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34619119

RESUMO

Because of their compromised deformability, heat denatured erythrocytes have been used as labeled probes to visualize spleen tissue or to assess the ability of the spleen to retain stiff red blood cells (RBCs) for over three decades, e.g., see Looareesuwan et al. N. Engl. J. Med. (1987). Despite their good accessibility, it is still an open question how heated RBCs compare to certain diseased RBCs in terms of their biomechanical and biorheological responses, which may undermine their effective usage and even lead to misleading experimental observations. To help answering this question, we perform a systematic computational study of the hemorheological properties of heated RBCs with several physiologically relevant static and hemodynamic settings, including optical-tweezers test, relaxation of prestretched RBCs, RBC traversal through a capillary-like channel and a spleen-like slit, and a viscometric rheology test. We show that our in silico RBC models agree well with existing experiments. Moreover, under static tests, heated RBCs exhibit deformability deterioration comparable to certain disease-impaired RBCs such as those in malaria. For RBC traversal under confinement (through microchannel or slit), heated RBCs show prolonged transit time or retention depending on the level of confinement and heating procedure, suggesting that carefully heat-treated RBCs may be useful for studying splenic- or vaso-occlusion in vascular pathologies. For the rheology test, we expand the existing bulk viscosity data of heated RBCs to a wider range of shear rates (1-1000 s-1) to represent most pathophysiological conditions in macro- or microcirculation. Although heated RBC suspension shows elevated viscosity comparable to certain diseased RBC suspensions under relatively high shear rates (100-1000 s-1), they underestimate the elevated viscosity (e.g., in sickle cell anemia) at low shear rates (<10 s-1). Our work provides mechanistic rationale for selective usage of heated RBC as a potentially useful model for studying the abnormal traversal dynamics and hemorheology in certain blood disorders.


Assuntos
Anemia Falciforme , Temperatura Alta , Fenômenos Biomecânicos , Deformação Eritrocítica , Eritrócitos , Hemorreologia , Humanos
2.
Soft Matter ; 17(37): 8446-8458, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34514478

RESUMO

The crucial role of the hemorheological characteristics of blood in a range of diagnoses, treatments and drug delivery mechanisms is widely accepted. Nonetheless, the literature on blood rheology remains inconclusive and sometimes even contradictory. This is in part due to natural variance of blood samples from one study to another, but also stems from fundamental differences in the consequences of the choice of rheometric flow employed. Here, and using a detailed and accurate computational scheme, we thoroughly study the role of flow type in measurement of blood viscosity. Performing these in silico measurements, we isolate the role of flow type and geometry at different hematocrit levels. We show that flow curves obtained in pressure-driven flows relevant to laminar circulatory flows deviate greatly from ones obtained in drag flow at the same hematocrit level. Our numerical platform also allows for the yield stress to be measured under quiescent conditions and without imposing any flow for different hematocrits. We discuss the scaling of the yield stress with the hematocrit level, and show that the differences in pressure vs. drag flows stem from the Red Blood Cell (RBC) orientation at different flow rates as well as the existence of a cell free layer close to the walls.


Assuntos
Viscosidade Sanguínea , Hemorreologia , Simulação por Computador , Eritrócitos , Hematócrito
3.
Front Public Health ; 9: 664841, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34222174

RESUMO

Background: Coronary heart disease (CHD) is one of the most common diseases in clinical cardiovascular practice, mainly afflicting the middle-aged and elderly. It will greatly affect elderly quality of life, and even affect their psychological and physical health. At present, CHD is treated with western drugs alone, but this can produce drug dependency. In recent years, Traditional Chinese Medicine (TCM) combine western drugs has been used as a complementary and alternative therapy, and its effectiveness and safety have been proven, attracting the attention of numerous researchers. Objective: Our study aimed to compare the efficacy of Aspirin with Combined Compound Danshen Dropping Pills had a superior effect on the treatment of Hemorheology and Blood Lipids in Middle-aged and Elderly Patients with CHD. Determine the effectiveness and safety of Aspirin with Combined Compound Danshen Dropping Pills in the treatment of CHD, and obtain high quality clinical evidence. Methods: Based on the PRISMA Statement, inclusion and exclusion criteria were formulated. Randomized controlled trials (RCTs) on the Effects of Aspirin with Combined Compound Danshen Dropping Pills on Hemorheology and Blood Lipids in Middle-aged and Elderly Patients with CHD were found following a search of 4 mainstream medical databases. RCTs found to meet the study's requirement were included; data information was then extracted, and the quality assessed using the Cochrane bias risk assessment tool. Through RevMan software, Meta analysis was carried out for overall TC, TG, HDL-C, LDL-C hematocrit, high shear viscosity, low shear viscosity, plasma viscosity, PAGM, and TXB2 effective rate. The relative risk (RR) and 95% confidence interval (95% CI) were calculated; heterogeneity was tested and its source found; publication bias was assessed through the Egger and Begg tests, and by means of funnel plots. Result: 22 RCTs were found, involving 1,987 cases. The results of the Meta analysis showed that, compared to drug therapy alone, Aspirin with Combined Compound Danshen Dropping Pills had a superior effect on the treatment of Hemorheology and Blood Lipids in Middle-aged and Elderly Patients with CHD. The meta analysis results show the effects on TC [MD = -0.91, 95% CI (-1.09, -0.73)], on TG [MD = -0.94, 95% CI (-1.22, -0.66)], on HDL-C [MD = 0.40, 95% CI (0.27, 0.53)], on LDL-C [MD = -0.99, 95% CI (-1.24, -0.74)], on hematocrit [MD = -2.69, 95% CI (-3.73, -1.65)], on high shear blood viscosity [MD = -1.11, 95% CI (-2.18, -0.05)], on low shear viscosity [MD = -0.79, 95% CI (-0.89, -0.68)], on plasma viscosity [MD = -0.26, 95% CI (-0.52, 0.01)], on PAMG [MD = -10.75, 95% CI (-16.84, -4.67)], and on TXB2 [MD = -11.84, 95% CI (-14.75, -8.92)]. The source of heterogeneity might be related to the state of patient, efficacy of drugs in the control group and difference in judgment criteria for efficacy. The Egger test and Begg test showed that publication bias did not occur in our study. Conclusions: The combination of compound dropping pill DSP with aspirin has some therapeutic effect on blood lipids and hemorheology in patients with CHD, ince some of the RCTs featured a very small sample size, the reliability and validity of our study's conclusion may have been affected as well; therefore, the explanation should be treated with some caution. In the future, a large number of higher-quality RCTs are still needed to confirm the results of our study.


Assuntos
Doença das Coronárias , Salvia miltiorrhiza , Idoso , Aspirina , Doença das Coronárias/tratamento farmacológico , Hemorreologia , Humanos , Lipídeos , Pessoa de Meia-Idade
4.
Biophys J ; 120(13): 2723-2733, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34087210

RESUMO

Hyperviscosity syndrome (HVS) is characterized by an increase of the blood viscosity by up to seven times the normal blood viscosity, resulting in disturbances to the circulation in the vasculature system. HVS is commonly associated with an increase of large plasma proteins and abnormalities in the properties of red blood cells, such as cell interactions, cell stiffness, and increased hematocrit. Here, we perform a systematic study of the effect of each biophysical factor on the viscosity of blood by employing the dissipative particle dynamic method. Our in silico platform enables manipulation of each parameter in isolation, providing a unique scheme to quantify and accurately investigate the role of each factor in increasing the blood viscosity. To study the effect of these four factors independently, each factor was elevated more than its values for a healthy blood while the other factors remained constant, and viscosity measurement was performed for different hematocrits and flow rates. Although all four factors were found to increase the overall blood viscosity, these increases were highly dependent on the hematocrit and the flow rates imposed. The effect of cell aggregation and cell concentration on blood viscosity were predominantly observed at low shear rates, in contrast to the more magnified role of cell rigidity and plasma viscosity at high shear rates. Additionally, cell-related factors increase the whole blood viscosity at high hematocrits compared with the relative role of plasma-related factors at lower hematocrits. Our results, mapped onto the flow rates and hematocrits along the circulatory system, provide a correlation to underpinning mechanisms for HVS findings in different blood vessels.


Assuntos
Viscosidade Sanguínea , Hemorreologia , Biofísica , Simulação por Computador , Hematócrito
5.
Sci Rep ; 11(1): 13144, 2021 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-34162963

RESUMO

Tumor progression and metastatic dissemination are driven by cell-intrinsic and biomechanical cues that favor the growth of life-threatening secondary tumors. We recently identified pro-metastatic vascular regions with blood flow profiles that are permissive for the arrest of circulating tumor cells. We have further established that such flow profiles also control endothelial remodeling, which favors extravasation of arrested CTCs. Yet, how shear forces control endothelial remodeling is unknown. In the present work, we aimed at dissecting the cellular and molecular mechanisms driving blood flow-dependent endothelial remodeling. Transcriptomic analysis of endothelial cells revealed that blood flow enhanced VEGFR signaling, among others. Using a combination of in vitro microfluidics and intravital imaging in zebrafish embryos, we now demonstrate that the early flow-driven endothelial response can be prevented upon specific inhibition of VEGFR tyrosine kinase and subsequent signaling. Inhibitory targeting of VEGFRs reduced endothelial remodeling and subsequent metastatic extravasation. These results confirm the importance of VEGFR-dependent endothelial remodeling as a driving force of CTC extravasation and metastatic dissemination. Furthermore, the present work suggests that therapies targeting endothelial remodeling might be a relevant clinical strategy in order to impede metastatic progression.


Assuntos
Endotélio Vascular/fisiologia , Hemorreologia , Migração Transendotelial e Transepitelial , Animais , Animais Geneticamente Modificados , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Embrião não Mamífero/irrigação sanguínea , Embrião não Mamífero/fisiologia , Regulação Neoplásica da Expressão Gênica , Ontologia Genética , Células Endoteliais da Veia Umbilical Humana , Humanos , Técnicas In Vitro , Microscopia Intravital , Microfluídica , Microscopia Confocal , Células Neoplásicas Circulantes , Quinazolinas/farmacologia , Quinazolinas/uso terapêutico , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Transdução de Sinais/fisiologia , Sunitinibe/farmacologia , Sunitinibe/uso terapêutico , Migração Transendotelial e Transepitelial/efeitos dos fármacos , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/fisiologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/fisiologia , Peixe-Zebra/embriologia
6.
Life Sci ; 280: 119714, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34146554

RESUMO

BACKGROUND: Altered red blood cell (RBC) deformability has been reported in Veterans with Gulf War Illness (GWI) who endorse exercise-induced symptom exacerbation and fatigue. However, it is unknown whether altered RBC deformability is worsened secondary to exercise. OBJECTIVE: To evaluate RBC deformability in response to maximal exercise in individuals with and without GWI. METHODS: Seventeen Veterans with GWI and 11 controls performed maximal exercise and provided blood samples (pre-, immediately post- and 60-min post-exercise). We calculated RBC deformation at infinite stress (EIMAX), shear stress for half-deformation (SS1/2) and their ratio (SS1/2/EIMAX) via repeated measures ANOVA with group and time as factors. RESULTS: A moderate interaction effect (p = 0.08, η2p = 0.10), large main effect for group (p = 0.02, η2p = 0.19) and moderate main effect for time (p = 0.20, η2p = 0.06) were observed for EIMAX, but only the main effect for group reached statistical significance. Changes in SS1/2 and SS1/2/EIMAX over time were similar between cases and controls as were main effects. CONCLUSIONS: Veterans with GWI had more deformable RBCs in comparison to controls that was unaffected by maximal exercise. Future studies to confirm our findings and identify associated mechanisms are warranted.


Assuntos
Exercício Físico , Hemorreologia , Síndrome do Golfo Pérsico/sangue , Contagem de Células Sanguíneas , Deformação Eritrocítica , Eritrócitos/citologia , Eritrócitos/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome do Golfo Pérsico/patologia , Veteranos
7.
Biomed Mater Eng ; 32(5): 295-308, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33998529

RESUMO

BACKGROUND: Embolization degree acts as an important factor affecting recurrence of aneurysm. OBJECTIVE: To analyze the role of hemodynamics parameters of different degrees of embolization in the occurrence, development and post-treatment of aneurysms, and to determine the specific factors causing the occurrence and recurrence of aneurysms after hemodynamics treatment. Our study provides a theoretical basis for the prevention and treatment of aneurysms. METHODS: Computed tomography angiography data of a patient with cerebral aneurysm was used to model 0%, 24%, 52%, 84% and 100% of endovascular embolization, respectively. The time average wall shear stress, time average wall shear stress, oscillatory shear index, hemodynamics formation index and relative retentive time were used to analyze the changes of hemodynamics indexes in different embolic models. RESULTS: With the increase of embolic rate, the values of time average wall shear stress, time average wall shear stress grade and aneurysm index formation gradually increased, and the values of relative retention time gradually decreased. Oscillatory shear index was higher in patients with incomplete embolization and decreased in patients with complete embolization. CONCLUSIONS: As the degree of embolization increased, the blood flow tended to stabilize, reducing the risk of cerebral aneurysm rupture, and finding that the wall of the vessel junction was susceptible to injury.


Assuntos
Aneurisma Roto , Embolização Terapêutica , Aneurisma Intracraniano , Simulação por Computador , Hemodinâmica , Hemorreologia , Humanos , Hidrodinâmica , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/terapia
8.
Ultrasonics ; 115: 106457, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33991980

RESUMO

Mechanical circulatory support systems (MCSSs) are crucial devices for transplants in patients with heart failure. The blood flowing through the MCSS can be recirculated or even stagnated in the event of critical blood flow issues. To avoid emergencies due to abnormal changes in the flow, continuous changes of the flowrate should be measured with high accuracy and robustness. For better flowrate measurements, a more advanced ultrasonic blood flowmeter (UFM), which is a noninvasive measurement tool, is needed. In this paper, we propose a novel UFM sensor module using a novel algorithm (Xero) that can exploit the advantages of both conventional cross-correlation (Xcorr) and zero-crossing (Zero) algorithms, using only the zero-crossing-based algorithm. To ensure the capability of our own developed and optimized ultrasonic sensor module for MCSSs, the accuracy, robustness, and continuous monitoring performance of the proposed algorithm were compared to those of conventional algorithms after application to the developed sensor module. The results show that Xero is superior to other algorithms for flowrate measurements under different environments and offers an error rate of at least 0.92%, higher robustness for changing fluid temperatures than conventional algorithms, and sensitive responses to sudden changes in flowrates. Thus, the proposed UFM system with Xero has a great potential for flowrate measurements in MCSSs.


Assuntos
Algoritmos , Fluxômetros , Hemorreologia , Ultrassom/instrumentação , Desenho de Equipamento , Humanos
9.
Ann Cardiol Angeiol (Paris) ; 70(3): 161-167, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33958189

RESUMO

PURPOSE: Spontaneous coronary artery dissection (SCAD) may occur in middle age population without any cardiovascular risk factor. We retrospectively evaluated anatomic features of 11 patients with SCAD using a coronary arteries computed tomography (CCT), compared to age and sex balanced patients who underwent CCT. MATERIAL AND METHODS: CCT was performed in 11 patients (7 females and 4 males) as follow-up in patients with SCAD (left anterior descending - LAD or circumflex artery - Cx) and compared, using the propensity score matching analysis, with 11 healthy patients. Several anatomic features were evaluated: Left main (LM) length, angle between descending coronary artery (LAD) and its first branch, angle between LAD and LM, distance from the annulus to RCA (a-RCA distance) and LM (a-LM distance) ostia and their ratio; ratio between LM length and length a-LM and tortuosity score of the vessel with SCAD. A fluid dynamic analysis has been performed to evaluate the effects on shear stress of vessels wall. RESULTS: LM length was significantly shorter in patients with SCAD versus healthy subjects (P=0.01) as well as LM length/a-LM (P=0.03) and the angle between LAD and the first adjacent branch was sharper (P<0.01). Tortuosity score showed a statistically significant difference between groups (P<0.001). Fluid dynamic analysis demonstrates that, in SCAD group, an angle<90 degree is present at the first bifurcation and it can be a cause of increased strain on vessel wall in patients with high tortuosity of coronary artery. CONCLUSION: Tortuosity and angle between the LAD and the adjacent arterial branch combined may determine increased shear stress on the vessel wall that increases the risk of SCAD.


Assuntos
Angiografia por Tomografia Computadorizada , Angiografia Coronária/métodos , Anomalias dos Vasos Coronários/diagnóstico por imagem , Pontuação de Propensão , Doenças Vasculares/congênito , Fatores Etários , Estudos de Casos e Controles , Anomalias dos Vasos Coronários/etiologia , Anomalias dos Vasos Coronários/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/patologia , Vasos Coronários/fisiopatologia , Feminino , Hemorreologia/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores Sexuais , Doenças Vasculares/diagnóstico por imagem , Doenças Vasculares/etiologia , Doenças Vasculares/fisiopatologia
10.
Zhen Ci Yan Jiu ; 46(4): 289-94, 2021 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-33931993

RESUMO

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the hemorheology and hepatic microcirculation in mice with chronic alcoholic liver injury (cALI), so as to explore the microcirculation mechanism of EA underlying regulating liver function in cALI mice. METHODS: Forty Kunming mice were randomly assigned to control, model, acupoint EA and non-acupoint EA groups, with 10 mice in each group. The cALI model was established by gavage with 50% ethanol (15 mL/kg,2 times per day with 8 hours' interval) for 28 d. Mice in the acupoint EA group received EA at bilateral "Zusanli" (ST36) and "Ganshu"(GB11) for 20 min, once daily for 14 d. And mice in the non-acupoint EA group received EA the spot about 1 cm lateral to GB11 and 0.5 cm lateral to ST36 respectively for 20 min, once daily for 14 d. The hepatic blood perfusion (HBP) of mice was detected by laser speckle perfusion imaging. The index of hemorheology, serum markers of liver function and hepatic histology in mice were observed by automatic blood rheometer, automatic bio-analysis machine and H.E. staining, respectively. RESULTS: Compared with the control group, the HBP of the model group was significantly decreased (P<0.05); the low-cut whole blood viscosity, plasma viscosity, and erythrocyte sedimentation level were significantly increased (P<0.05), and the red blood cell deformation index was significantly decreased (P<0.05); serum alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) increased significantly (P<0.05) in the model group. Hepatocyte steatosis accompanied by inflammatory cell infiltration and focal necrosis was observed in the model group. After EA at ST36 and GB11, and in comparison with the model group showed that the HBP was significantly increased (P<0.05); the low-cut whole blood viscosity, plasma viscosity, erythrocyte sedimentation rate and serum GGT were significantly decreased (P<0.05), and the red blood cell deformation index was significantly increased (P<0.05); the degree of fatty degeneration in the liver tissue was reduced, and the focal necrosis was reduced. The plasma viscosity, erythrocyte sedimentation rate were significantly decreased (P<0.05), and the red blood cell deformation index was significantly increased in the non-acupoint EA group relevant to the model group (P<0.05). The erythrocyte sedimentation rate and the red blood cell deformation index of the acupoint EA group was significantly lower than that of the non-acupoint EA group (P<0.05). CONCLUSION: EA at ST36 and GB11 could improve the hemorheological disorder and the hepatic microcirculation, and inhibit the deve-lopment of liver injury in cALI mice.


Assuntos
Eletroacupuntura , Pontos de Acupuntura , Animais , Hemorreologia , Fígado , Camundongos , Microcirculação , Ratos , Ratos Sprague-Dawley
11.
Soft Matter ; 17(18): 4766-4774, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33870399

RESUMO

Recent advances in hemorheology are extended to study blood rheology across species, which has important clinical implications particularly in intravenous drug scaleup as drugs undergoing clinical trials are first tested in animals. Some of the first hemorheological measurements from seven different species under both steady and transient shear conditions are presented and modeled using a rheological model developed and validated on human blood rheology fit to 20 different donors. Despite similar physiological properties across the blood samples from different species, significant differences are observed, particularly at low shear rates. Blood from species that form rouleaux exhibit a yield-like behavior and enhanced viscoelasticity at low shear rates, while blood from species without rouleaux exhibit nearly Newtonian behavior at similar shear rates. Viscoelasticity due to blood cell deformation is evident for all species at high shear rates. Novel, unidirectional large amplitude oscillatory shear measurements differentiate species. Using the newly acquired data in combination with previous literature data, a new allometric scaling relation is suggested for the low-shear blood viscosity for various mammalian evolutionary orders. Using an established model for arterial branching across species, it is conjectured that the observed hemorheological scaling across species is driven by maintaining a constant wall shear stress in arterial vessels.


Assuntos
Viscosidade Sanguínea , Hemorreologia , Animais , Humanos , Reologia , Estresse Mecânico , Viscosidade
12.
Int J Mol Sci ; 22(5)2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33800818

RESUMO

This work presents a semi-quantitative spectroscopic approach, including FTIR-ATR and Raman spectroscopies, for the biochemical analysis of red blood cells (RBCs) supported by the biochemical, morphological and rheological reference techniques. This multi-modal approach provided the description of the RBC alterations at the molecular level in a model of accelerated aging induced by administration of D-galactose (D-gal), in comparison to natural aging. Such an approach allowed to conclude that most age-related biochemical RBC membrane changes (a decrease in lipid unsaturation and the level of phospholipids, or an increase in acyl chain shortening) as well as alterations in the morphological parameters and RBC deformability are well reflected in the D-gal model of accelerated aging. Similarly, as in natural aging, a decrease in LDL level in blood plasma and no changes in the fraction of glucose, creatinine, total cholesterol, HDL, iron, or triglycerides were observed during the course of accelerated aging. Contrary to natural aging, the D-gal model led to an increase in cholesterol esters and the fraction of total esterified lipids in RBC membranes, and evoked significant changes in the secondary structure of the membrane proteins. Moreover, a significant decrease in the phosphorous level of blood plasma was specific for the D-gal model. On the other hand, natural aging induced stronger changes in the secondary structures of the proteins of the RBCs' interior. This work proves that research on the aging mechanism, especially in circulation-related diseases, should employ the D-gal model with caution. Nonetheless, the D-gal model enables to imitate age-related rheological alterations in RBCs, although they are partially derived from different changes observed in the RBC membrane at the molecular level.


Assuntos
Senilidade Prematura/induzido quimicamente , Envelhecimento/sangue , Modelos Animais de Doenças , Membrana Eritrocítica/química , Galactose/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Senilidade Prematura/sangue , Animais , Citosol/química , Envelhecimento Eritrocítico/efeitos dos fármacos , Deformação Eritrocítica/efeitos dos fármacos , Índices de Eritrócitos/efeitos dos fármacos , Membrana Eritrocítica/efeitos dos fármacos , Radicais Livres/toxicidade , Galactose/farmacologia , Hemorreologia/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fósforo/sangue , Projetos de Pesquisa
13.
Clin Hemorheol Microcirc ; 78(2): 187-198, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33579832

RESUMO

BACKGROUND: Red blood cell (RBC) aggregation plays an important role in the physiological processes of the microcirculation. The complete mechanism of aggregation is still unclear, and it is influenced by several cellular and plasmatic factors. One of these factors is the hematocrit (Hct). OBJECTIVE: We hypothesized that the relation of RBC aggregation and Hct differs between species. METHODS: From anticoagulated blood samples of healthy volunteers, rats, dogs, and pigs, 20, 40, and 60 %Hct RBC, autologous plasma suspensions were prepared. Hematological parameters and RBC aggregation was determined by light-transmission and light-reflection method. RESULTS: Suspensions at 20%and 60%Hct expressed lower RBC aggregation than of 40%Hct suspensions, showing inter-species differences. By curve fitting the Hct at the highest aggregation value differed in species (human: 45.25%- M 5 s, 40.86%- amp; rat: 44.44 %- M1 10 s, 39.37%- amp; dog: 42.48%- M 5 s, 44.29%- amp; pig: 47.63%- M 5 s, 52.8%- amp). CONCLUSION: RBC aggregation - hematocrit relation shows inter-species differences. Human blood was found to be the most sensitive for hematocrit changes. The more obvious differences could be detected by M 5 s by light-transmission method and amplitude parameter using light-reflection method.


Assuntos
Agregação Eritrocítica , Eritrócitos/fisiologia , Hematócrito , Hemorreologia , Adulto , Animais , Coagulação Sanguínea , Viscosidade Sanguínea , Cães , Eritrócitos/citologia , Humanos , Masculino , Microcirculação , Ratos , Suínos
14.
Oxid Med Cell Longev ; 2021: 8891544, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33628394

RESUMO

Background: Resveratrol (RSV), one of the SIRT1 agonists, has the ability of alleviating severe acute pancreatitis (SAP); however, the concrete protective mechanism remains unknown. It is noteworthy that microcirculation disturbance plays a vital role in SAP, and the SIRT1/FOX1 axis can regulate microcirculation. Therefore, this study is aimed at ascertaining what is the underlying mechanism of the protective effect of RSV on SAP, and whether it is associated with alleviating microcirculation disturbance by regulating the SIRT1/FOX1 axis. Method: The model of SAP was induced by retrograde injection of sodium taurodeoxycholate into the bile duct of the rats. The pancreatic wet/dry weight, ET/NO, and TXB2/6-keto-PGF1α ratios; microcirculatory function; and SIRT1 activity were examined. ELISA was used to examine the serum level of lipase, amylase, hemorheology, ET, NO, TXB2, and 6-keto-PGF1α and the content of SIRT1, VEGF, Ang I, and Ang II in the pancreas. RT-PCR was used to examine the mRNA level of VEGF, Ang I, and Ang II. Western blotting was used to detect SIRT1, FOXO1, and acetyl-FOXO1. Immunoprecipitation was used to examine the interaction of SIRT1 and FOXO1. Results: Resveratrol can significantly decrease the expression of lipase, amylase, acetyl-FOXO1, VEGF, Ang II, ET, NO, TXB2, and 6-keto-PGF1α and the ratio of wet/dry weight, ET/NO, and TXB2/6-keto-PGF1α by improving microcirculatory dysfunction and blood viscosity in SAP. Moreover, resveratrol can also promote the interaction of SIRT1 and FOXO1 and increase SIRT1 activity and the expression of SIRT1 and Ang I. The SIRT1 inhibitor, Sirtinol (EX527), obliviously reversed the effects of RSV on SAP. Conclusion: Resveratrol can protect rats against SAP, and its protective mechanism is associated with suppressing microcirculation disturbance through activating SIRT1-FOXO1 axis.


Assuntos
Microcirculação , Proteínas do Tecido Nervoso/metabolismo , Pancreatite/tratamento farmacológico , Pancreatite/fisiopatologia , Resveratrol/uso terapêutico , Sirtuína 1/metabolismo , Amilases/sangue , Animais , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Hemorreologia/efeitos dos fármacos , Lipase/sangue , Masculino , Microcirculação/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Pâncreas/patologia , Pancreatite/sangue , Pancreatite/enzimologia , Ligação Proteica/efeitos dos fármacos , Ratos Sprague-Dawley , Resveratrol/química , Resveratrol/farmacologia
15.
Sci Rep ; 11(1): 2800, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33531664

RESUMO

Cancer is a leading cause of death and disease worldwide. However, while the survival for patients with primary cancers is improving, the ability to prevent metastatic cancer has not. Once patients develop metastases, their prognosis is dismal. A critical step in metastasis is the transit of cancer cells in the circulatory system. In this hostile microenvironment, variations in pressure and flow can change cellular behavior. However, the effects that circulation has on cancer cells and the metastatic process remain unclear. To further understand this process, we engineered a closed-loop fluidic system to analyze molecular changes induced by variations in flow rate and pressure on primary tumor-derived lung adenocarcinoma cells. We found that cancer cells overexpress epithelial-to-mesenchymal transition markers TWIST1 and SNAI2, as well as stem-like marker CD44 (but not CD133, SOX2 and/or NANOG). Moreover, these cells display a fourfold increased percentage of side population cells and have an increased propensity for migration. In vivo, surviving circulatory cells lead to decreased survival in rodents. These results suggest that cancer cells that express a specific circulatory transition phenotype and are enriched in side population cells are able to survive prolonged circulatory stress and lead to increased metastatic disease and shorter survival.


Assuntos
Adenocarcinoma de Pulmão/secundário , Hemorreologia , Neoplasias Pulmonares/patologia , Células-Tronco Neoplásicas/patologia , Células da Side Population/patologia , Células A549 , Adenocarcinoma de Pulmão/irrigação sanguínea , Animais , Movimento Celular , Sobrevivência Celular , Simulação por Computador , Transição Epitelial-Mesenquimal , Feminino , Humanos , Pulmão/irrigação sanguínea , Pulmão/patologia , Neoplasias Pulmonares/irrigação sanguínea , Técnicas Analíticas Microfluídicas , Ratos , Estresse Mecânico , Microambiente Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Sci Rep ; 11(1): 2642, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514847

RESUMO

Aggregation of human red blood cells (RBC) is central to various pathological conditions from bacterial infections to cancer. When left at low shear conditions or at hemostasis, RBCs form aggregates, which resemble stacks of coins, known as 'rouleaux'. We experimentally examined the interfacial dielectric dispersion of aggregating RBCs. Hetastarch, an RBC aggregation agent, is used to mimic conditions leading to aggregation. Hetastrach concentration is incrementally increased in blood from healthy donors to measure the sensitivity of the technique. Time lapse electrical impedance measurements were conducted as red blood cells form rouleaux and sediment in a PDMS chamber. Theoretical modeling was used for obtaining complex permittivity of an effective single red blood cell aggregate at various concentrations of hetastarch. Time response of red blood cells' impedance was also studied to parametrize the time evolution of impedance data. Single aggregate permittivity at the onset of aggregation, evolution of interfacial dispersion parameters, and sedimentation kinetics allowed us to distinguish differential aggregation in blood.


Assuntos
Sedimentação Sanguínea/efeitos dos fármacos , Agregação Eritrocítica/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Derivados de Hidroxietil Amido/farmacologia , Agregação Eritrocítica/fisiologia , Eritrócitos/fisiologia , Hemorreologia , Hemostasia/efeitos dos fármacos , Humanos , Cinética , Modelos Teóricos , Fenômenos Físicos
17.
Clin Hemorheol Microcirc ; 77(4): 395-410, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33386795

RESUMO

BACKGROUND: Calcium, vitamin D and insulin resistance are linked to osteoporosis and cardiovascular disease in menopause. OBJECTIVE: Determine if hemorheological parameters related to blood viscosity in microcirculation are linked to calcium metabolism and insulin resistance in menopause. METHODS: 25-Hydroxyvitamin D (25(OH)D)), 1, 25-dihydroxyvitamin D3 (1, 25(OH)2D), parathyroid hormone, ionized calcium, glucose, insulin and hemoglobin A1c were measured in blood from 43 volunteers. Red blood cells (RBC) aggregation, RBC deformability and whole blood viscosity were also performed. RESULTS: 25(OH)D showed a positive correlation with RBC deformability 0.60 Pa. Subjects with 25(OH)D≤29.00 ng/mL had lower RBC deformability 0.60 Pa, and higher RBC aggregation and higher HOMA-IR. Ionized calcium showed a negative correlation with RBC aggregation. Subjects with ionized calcium ≤1.24 mmol/L showed higher RBC aggregation. There was a positive correlation between HOMA-IR and RBC aggregation and HOMA-IR showed a negative correlation with RBC deformability 0.30 Pa. Subjects with HOMA-IR <1.80 showed lower RBC aggregation and higher RBC deformability at 0.30 Pa, 0.60 Pa, 1.20 Pa, 3.0 Pa and 6.0 Pa. CONCLUSION: Low 25(OH)D, low ionized calcium and high HOMA-IR are related to impaired hemorheology in menopause. RBC aggregation and deformability can be used as biomarkers of calcium metabolism and insulin resistance in menopause.


Assuntos
Biomarcadores/sangue , Cálcio/metabolismo , Doenças Cardiovasculares/sangue , Hemorreologia/genética , Resistência à Insulina/genética , Idoso , Deformação Eritrocítica , Feminino , Humanos , Pessoa de Meia-Idade , Pós-Menopausa
18.
IEEE Rev Biomed Eng ; 14: 327-341, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32746370

RESUMO

Blood flow in the human vascular system is a complex to understand example of fluid dynamics in a closed conduit. Any irregularities in the hemodynamics may lead to lethal cardiovascular disease like heart attack, heart failure and ischemia. Numerical simulation of hemodynamics in the blood vessel can facilitate a thorough understanding of blood flow and its interaction with the adjacent vessel wall. A good simulation approach for blood flow can be helpful in early prediction and diagnosis of the mentioned disease. The simulation outcomes may also provide decision support for surgical planning and medical implants. This study reports an extensive review of various approaches adopted to analyze the influence of blood rheological characteristics in a different class of blood vessels. In particular, emphasis was given on the identification of best possible rheological model to effectively solve the hemodynamics inside different blood vessels. The performance capability of different rheological models was discussed for different classes and conditions of vessels and the best/poor performing models are listed out. The Carreau, Casson and generalized power-law models were appeared to be superior for solving the blood flow at all shear rates. In contrast, power law, Walburn-Scheck and Herchel-Bulkley model lacks behind in the purpose.


Assuntos
Vasos Sanguíneos/fisiologia , Hemorreologia/fisiologia , Modelos Cardiovasculares , Circulação Sanguínea/fisiologia , Viscosidade Sanguínea/fisiologia , Simulação por Computador , Humanos , Masculino
19.
Med Sci Sports Exerc ; 53(3): 479-486, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32925494

RESUMO

PURPOSE: In healthy adults, the impairment of vascular function associated with prolonged sitting can be mitigated with intermittent brief bouts of activity. It is unknown whether these benefits extend to women with polycystic ovary syndrome (PCOS), in whom vascular function is typically impaired and sitting time is high. We examined the acute effect of regularly interrupting sitting time with brief simple resistance activities (SRA) on vascular function in PCOS. METHODS: In a randomized crossover trial, 13 physically inactive women with PCOS (18-45 yr) completed two 3.5-h conditions: 1) uninterrupted sitting (SIT) and 2) sitting interrupted by 3-min bouts of SRA every 30 min. Femoral artery flow-mediated dilation (FMD), resting shear rate, and resting blood flow were measured at 0, 1, and 3.5 h. RESULTS: Mean resting femoral shear rate, averaged across the 3.5 h, significantly increased in the SRA condition relative to the SIT condition (40.1 ± 6.1 vs 62.8 ± 6.1 s-1, P < 0.0001). In addition, mean resting blood flow also significantly increased across the 3.5 h for SRA relative to SIT (45.0 ± 9.8 vs 72.8 ± 9.9 mL·min-1, P < 0.0001). There were no differences between conditions in the temporal change in femoral artery FMD across 3.5 h (Ptime-condition > 0.05 for all). CONCLUSION: Frequently interrupting sitting with SRA acutely increased resting shear rate and blood flow in women with PCOS but did not alter FMD. With sedentary behavior increasing in prevalence, longer-term studies of similar interventions to reduce and break up sitting time are warranted.


Assuntos
Endotélio Vascular/fisiopatologia , Síndrome do Ovário Policístico/fisiopatologia , Treinamento de Força/métodos , Postura Sentada , Adulto , Estudos Cross-Over , Feminino , Artéria Femoral/fisiologia , Hemorreologia/fisiologia , Humanos , Fluxo Sanguíneo Regional , Comportamento Sedentário , Fatores de Tempo , Vasodilatação/fisiologia
20.
Clin Hemorheol Microcirc ; 77(2): 183-194, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32925001

RESUMO

BACKGROUND: Diabetic ketoacidosis (DKA) is a medical emergency with a high mortality rate and is associated with severe metabolic acidosis and dehydration. DKA patients have an increased risk of arterial and venous thromboembolism, however little is known about this metabolic derangement in the first 24 hours of admission and to assess its effect on coagulation. We therefore utilised a novel functional marker of clot microstructure (fractal dimension - df) to assess these changes within the first 24 hours. METHODS: Prospective single centre observational study to demonstrate whether the tendency of blood clot formation differs in DKA patients. RESULTS: 15 DKA patients and 15 healthy matched controls were recruited. Mean df in the healthy control group was 1.74±0.03. An elevated df of 1.78±0.07 was observed in patients with DKA on admission. The mean pH on admission was 7.14±0.13 and the lactate was 3.6±2.0. df changed significantly in response to standard treatment and was significantly reduced to 1.68±0.09 (2-6& h) and to 1.66±0.08 at 24& h (p < 0.01 One-way ANOVA). df also correlated significantly with lactate and pH (Pearson correlation coefficient 0.479 and -0.675 respectively, p < 0.05). CONCLUSIONS: DKA patients at presentation have a densely organising less permeable thrombogenic clot microstructure as evidenced by high df. These structural changes are due to a combination of dehydration and a profound metabolic acidosis, which was reversed with treatment. These changes were not mirrored in standard clinical markers of thromboge-nicity.


Assuntos
Biomarcadores/sangue , Cetoacidose Diabética/tratamento farmacológico , Hemorreologia/fisiologia , Trombose/tratamento farmacológico , Estudos de Casos e Controles , Cetoacidose Diabética/sangue , Feminino , Fractais , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...