Clinical Hemorheology and Microcirculation - Volume 64, issue 4

Authors: Gori, Tommaso | Jung, Friedrich

Article Type: Editorial

DOI: 10.3233/CH-168005

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 507-508, 2016

Authors: Antonova, Nadia

Article Type: Research Article

Abstract: The lecture was presented during the Fåhraeus award ceremony for 2016 at the University of Lisbon. It summarizes the main results and some of the more important hemorheological contributions achieved in the Laboratory of Biodynamics and Biorheology of the Institute of Mechanics to BAS and in collaboration with other laboratories of the research group, involved in many studies explaining hemorheological disturbances in various clinical conditions. An original method for the study of microstructural changes in the biological fluids by measuring the electrical conductivity simultaneously with the the rheological properties of red blood cells (RBC) in the whole blood and red …blood cell suspensions in a viscometric flow was suggested. The influence of the disturbed hemorheological parameters on the common carotid artery and cerebral blood flow was studied. Analysis of blood flow in the common carotid artery bifurcation with stenosis was done. This lecture does not claim to be a comprehensive review, and many important studies were not cited. The author would like to acknowledge the valuable collaboration of all those cited in the reference list. Show more

Keywords: Hemorheology, cerebrovascular disease, diabetes mellitus type 2, electrorheological method, blood conductivity, common carotid artery hemodynamics, common carotid artery bifurcation, stenosis, numerical analysis

DOI: 10.3233/CH-168001

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 509-515, 2016

Authors: Saldanha, Carlota

Article Type: Research Article

Abstract: Nitric oxide (NO) produced by endothelial cells interacts with erythrocyte through band 3 protein, being scavenged by haemoglobin. A signal transduction mechanism involving protein Gi and protein band 3 stimulates erythrocyte NO efflux when acetylcholine (ACh) binds to erythrocyte membrane acetylcholinesterase. Binding of normal plasma fibrinogen (Fib) levels, to erythrocyte membrane CD47 decreases the NO efflux. When high Fib concentration and ACh were present the efflux of NO from erythrocytes was normalized. The increased NO efflux from erythrocytes in presence of high Fib concentration and band 3 phosphorylation is reinforced in the presence of 4N1K an agonist peptide of CD47. …When both Fib and 4N1K are present the NO efflux from erythrocytes is higher or not affected according lower or high levels of cAMP. Erythrocyte NO efflux in patients with systemic lupus erythematous and rheumatoid attrite was significantly negative associated with carotid intima-media thickness. In patients with amyotrophic lateral sclerosis erythrocyte NO content is preserved and an inverse association between respiratory function and NO efflux from the erythrocyte was verified. Sepsis patients before dead at 24 h showed higher efflux of NO from erythrocytes that worsening the blood sub lingual microcirculation observed by high unequal blood flow and high microvascular flow index. The in vivo animal models either of inflammation or of hypertension evidenced that the NO efflux from erythrocyte decrease as a compensatory mechanism. All studies conducted since 2000 where we demonstrated the existence NO inside the erythrocyte by fluorescence microscopy, and after their signaling pathway needs more development translational research for news therapeutics and further application in not invasive therapy to vascular inflammatory diseases. Show more

Keywords: Nitric oxide, erythrocyte, fibrinogen, signal transduction, inflammation, vascular diseases

DOI: 10.3233/CH-168028

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 517-520, 2016

Authors: Gori, Tommaso

Article Type: Research Article

Abstract: Vascular homeostasis involves endothelial function, smooth muscle function, central hemodynamics, and their interactions with blood. In this complex balance, the role of hemorheological parameters still needs to be defined, particularly with regards to its clinical implications. While the importance of microcirculation is being increasingly appreciated, the mechanisms of hemorheology and their implications are still not. This will be the challenge of our Society for the next years.

Keywords: Coronary slow flow, endothelial function, viscosity, hematocrit, platelets

DOI: 10.3233/CH-168017

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 521-524, 2016

Authors: Stoltz, J.F.

Article Type: Research Article

Abstract: The word “Biorheology” was introduced in 1948 during the first international congress on Rheology but “hemorheology” was first employed in 1951 during a meeting of the American Institute of Physics. Basically this science is related to physics and mechanics. The first international conference devoted to hemorheology was organized by AL Copley in Reykjavik (Iceland) in July 1969 and an International Society on Hemorheology was created. But after Reykjavik this society was named “International Society of Biorheology”. The term “Clinical Hemorheology” was proposed in Nancy in 1979 which was named “First European Symposium on Clinical Hemorheology” and an European Coordinating Committee …on Clinical Hemorheology (ECCCH) was created. The European Society on Clinical Hemorheology and Microcirculation was in fact created in Frankfurt in 1990 initiated by Albrecht Ehrly. In Nancy it was also decided to create a European Award named “Fahraeus Medal”. After Nancy, the ECCCH and the European Society organized symposia in London, Baden Baden, Sienna, Frankfurt, Bordeaux,  ...  , Sofia  ...   and now Lisboa. Now it is necessary to give new directions for the development of Hemorheology and Clinical Hemorheology. Different ways can be considered: – Development of new theoretical models which take into account the heterogeneity of blood and blood vessel – Research on cell mechanobiology and mechanotransduction (leucocyte, endothelial and smooth muscle cells) – Study of cellular interactions (aggregation, adhesion,  ...) and intracellular transport – Membrane rheology and concept of molecular fluidity – Dynamic blood coagulation in relation with molecular reactions – Development of metrology for clinical hemorheology Development of new theoretical models which take into account the heterogeneity of blood and blood vessel Research on cell mechanobiology and mechanotransduction (leucocyte, endothelial and smooth muscle cells) Study of cellular interactions (aggregation, adhesion,  ...) and intracellular transport Membrane rheology and concept of molecular fluidity Dynamic blood coagulation in relation with molecular reactions Development of metrology for clinical hemorheology Show more

Keywords: Hemorheology, history, mechanobiology, cellular interactions

DOI: 10.3233/CH-168035

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 525-539, 2016

Authors: Rampling, M.W.

Article Type: Research Article

Abstract: An obvious candidate for the seminal event in the history of haemorheology is Harvey’s presentation of the concept of the circulation of the blood. Prior to this, the ideas concerning the movement of blood were based, in Europe and Middle East, largely on the principles laid down by Galen, and these had been, in effect, dogma for nearly a millennium and a half. These principles were basically that blood is formed in the liver, thence it travels to the bodily organs and is consumed –hence there is one-way flow and no circulation of the blood at all. Harvey’s revolutionary idea …that blood circulates repeatedly around the cardiovascular system laid the foundation for haemorheology because once that idea was accepted then the fluidity of the blood immediately became potentially of crucial importance – and haemorheology was conceived. In this paper the ideas that preceded Harvey will be presented, i.e. those of Galen, Ibn al-Nafis, Vesalius, Fabricius and Colombo etc. Harvey’s awareness of this background, due mainly to time spent in Padua, triggered his many experimental investigations and discoveries. Ultimately, these led to his astonishing insights published in De Mortu Cordis in 1628 which changed the understanding of the cardio-vascular system forever. Show more

DOI: 10.3233/CH-168031

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 541-549, 2016

Authors: Vaz Carneiro, António

Article Type: Research Article

Abstract: Clinicians are used to treat individual patients, and therefore may feel that clinical trials and systematic reviews do not give information for optimal treatment of the single patient. Evidence Based Medicine (EBM) is the integration of research evidence (from clinically relevant studies conducted using sound methodology) with clinical expertise (clinician’s cumulated experience) and patient values (personal preferences and unique concerns and expectations). The practical steps of EBM include: 1) assess the patient, 2) ask the clinical question, 3) acquire the evidence, 4) critically appraise the evidence, 5) apply the results to the patient and 6) self-evaluate one’s practice. Clinical studies in clinical hemorheology …include – among other – interventions in vascular medicine: coronary disease, stroke, peripheral vascular disease, venous insufficiency and thrombosis, etc. Of these, we will present some practical steps on how to apply therapy results of stroke studies to the individual patient (this addresses step number 5 in the previous definition of EBM practice). We will do this by discussing the differences between internal and external validity of clinical trials, and defining the importance of baseline risks to choose therapy using the data from the best and most useful studies available. In the end, clinicians will understand how to use evidence effectively. Show more

Keywords: Hemorheology, evidence-based medicine, external validity of clinical trials, stroke treatment

DOI: 10.3233/CH-168043

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 551-555, 2016

Authors: Barbacena, Pedro | Carvalho, Joana R. | Franco, Claudio A.

Article Type: Research Article

Abstract: In this ESCHM 2016 conference talk report, we summarise two recently published original articles Franco et al. PLoS Biology 2015 and Franco et al. eLIFE 2016. The vascular network undergoes extensive vessel remodelling to become fully functional. Is it well established that blood flow is a main driver for vascular remodelling. It has also been proposed that vessel pruning is a central process within physiological vessel remodelling. However, despite its central function, the cellular and molecular mechanisms regulating vessel regression, and their interaction with blood flow patterns, remain largely unexplained. We investigated the cellular process governing developmental vascular remodelling in …mouse and zebrafish. We established that polarised reorganization of endothelial cells is at the core of vessel regression, representing vessel anastomosis in reverse. Moreover, we established for the first time an axial polarity map for all endothelial cells together with an in silico method for the computation of the haemodynamic forces in the murine retinal vasculature. Using network-level analysis and microfluidics, we showed that endothelial non-canonical Wnt signalling regulates endothelial sensitivity to shear forces. Loss of Wnt5a/11 renders endothelial cells more sensitive to shear, resulting in axial polarisation at lower shear stress levels. Collectively our data suggest that non-canonical Wnt signalling stabilizes forming vascular networks by reducing endothelial shear sensitivity, thus keeping vessels open under low flow conditions that prevail in the primitive plexus. Show more

Keywords: Endothelial cells, vascular remodelling, shear stress, non-canonical Wnt signalling

DOI: 10.3233/CH-168006

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 557-563, 2016

Authors: Toth, Andras | Sandor, Barbara | Marton, Zsolt | Kesmarky, Gabor | Szabados, Eszter | Kehl, Daniel | Juricskay, Istvan | Czopf, Laszlo | Toth, Kalman

Article Type: Research Article

Abstract: During the past decades, our group have investigated the hemorheological parameters (HPs) of more than 1,000 patients with various forms of ischemic heart disease (IHD). Our data indicate that HPs are altered in patients with IHD and the extent of the alterations is in good correlation with the clinical severity of the disease. Our findings have also proven that HPs play a critical role in the pathogenesis of myocardial ischemia. The lack of regular exercise is an important cardiovascular risk factor. Regular physical activity – as part of the cardiovascular rehabilitation training program (CRP) – is recommended for the …treatment of IHD and the prevention of first or further cardiovascular events. To estimate the beneficial hemorheological effects of CRP, compared to patients after a coronary event or intervention and not participating in CRP, the data of four of our prospective studies (three non-CRP and one CRP-participating) were evaluated. Hematocrit (Hct), plasma and whole blood viscosity (WBV), Hct/WBV ratio significantly (p  < 0.05) increased in the non-CRP groups during the 6–12 months follow-up, while in the CRP group they significantly decreased (p  < 0.05). Red blood cell aggregation decreased in a much greater manner in the CRP group. Our results indicate that CRP has beneficial hemorheological effects and is able to reverse the deterioration of HPs after coronary events or intervention. Show more

Keywords: Ischemic heart disease, cardiovascular prevention, acute coronary syndrome, percutaneous coronary intervention, hemorheological parameters

DOI: 10.3233/CH-168038

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 565-574, 2016

Authors: Reinhart, Walter H.

Article Type: Research Article

Abstract: The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50–60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5–70μ m channels the optimum Hct was 60–70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values. In healthy, well trained athletes …an increase of the Hct to supra-normal levels can increase exercise performance. These data with healthy individuals suggest that the optimum Hct for oxygen transport may be higher than the physiological range (35–40% in women, 39–50% in men). This is in contrast to clinical observations. Large clinical studies have repeatedly shown that a correction of anemia in a variety of disorders such as chronic kidney disease, heart failure, coronary syndrome, oncology, acute gastrointestinal bleeding, critical care, or surgery have better clinical outcomes when restrictive transfusion strategies are applied. Actual guidelines, therefore, recommend a transfusion threshold of 7–8 g/dL hemoglobin (Hct 20–24%) in stable, hospitalized patients. The discrepancy between the optimum Hct in health and disease may be due to factors such as decreased perfusion pressures (low cardiac output, vascular stenoses, change in vascular tone), endothelial cell dysfunction, leukocyte adhesion and others. Show more

Keywords: Erythrocyte, hematocrit, viscosity, oxygen transport, microcirculation

DOI: 10.3233/CH-168032

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 575-585, 2016

Authors: Priezzhev, A. | Lee, K.

Article Type: Research Article

Abstract: Laser trapping and manipulation of blood cells without mechanical contact have become feasible with implication of laser tweezers. They open up new horizons for the hemorheologic researches, offer new possibilities for studying live cells interactions on individual cell level under the influence of different endogenous and exogenous factors. The operation principle of laser tweezers is based on the property of strongly focused laser beam to act on a dielectric microparticle located in the vicinity of the beam waist with a force that drives the particle to the equilibrium location and holds it there. If the beam waist position is manipulated, …so is the position of the particle. The displacement of the particle from the equilibrium position by external forces can be calibrated so that these forces can be precisely measured in the range ca. 0.1–100 pN. This is the range of forces of elastic deformation of blood cells and of their interaction with each other and with vessel walls. Being able to measure these forces without mechanical contact allows for studying on single cell level the mechanisms of interactions that was impossible earlier. Here we discuss the basic features of these techniques and give some examples of challenging hemorheologic studies. Show more

Keywords: Red blood cell, interaction, aggregation, critical shear stress, temperature, shearing-geometry, single-cell level measurements, optical tweezers, microfluidic flow

DOI: 10.3233/CH-168030

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 587-592, 2016

Authors: Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Fédou, Christine | Raynaud de Mauverger, Eric

Article Type: Research Article

Abstract: Equations of blood viscosity provide a prediction of the ‘optimal’ hematocrit’ (hct) as the hct resulting in the highest value of the bell-shaped curve of hematocrit/viscosity ratio h/η. We investigated if overweight and obesity have an influence on these parameters. We compared 32 normal weight subjects, 40 overweight (BMI 25–30) and 38 obese subjects. There was no difference in the theoretical curve of h/η. The actual h/η is the same in the 3 groups but is always higher than the theoretical h/η in all groups. The actual h/η is lower in overweight than controls (p  = 0.011). Modeling yields the same value …of theoretical optimal hct across BMI classes. The 3 groups have the same values of actual hct, but actual is significantly lower than optimal in all cases (p  < 0.001). Hematocrit is lower than predicted due to a discrepancy between predicted and actual h/η which is due to the inter-subject variability of RBC rigidity ...   The discrepancy between optimal and actual h/η is negatively correlated to RBC rigidity indexes even if the model uses a fixed value of these indexes. Thus keeping in mind that the optimal hct should not be the same in the various parts of the vascular bed, its theoretical prediction with Quemada's equation appears to predict a value higher than actual hematocrit but well correlated to it, and the agreement between optimal and actual hct is dependent on RBC flexibility. This leads to think that the body sets hematocrit below its ideal value in sedentary subjects in order to cope with the need of increasing blood viscosity factors in case of exercise without impairing O2 supply to tissues. Show more

Keywords: Blood viscosity, hematocrit, exercise, erythrocyte deformability, obesity

DOI: 10.3233/CH-168013

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 593-601, 2016

Authors: Varlet-Marie, Emmanuelle | Joré, Céline | Brun, Jean-Frédéric

Article Type: Research Article

Abstract: Bioelectrical impedancemetry (BIA) has been used to evaluate hematocrit and red cell aggregability in vitro but whole body impedance measurements are also correlated to some hemorheologic factors, suggesting a relationship between viscosity factors and electric properties of blood. We repeatedly reported correlations with whole body BIA and hematocrit, whole blood viscosity and plasma viscosity, red cell rigidity and RBC aggregation. The SBIA Inbody 770 modelizes body as 5 cylinders and measures impedance at 1, 5, 50, 250, 500, and 1000 kHz. With the SBIA we found that hematocrit is best correlated to leg reactance at 50 kHz but also to leg …impedance at 1 and 5 kHz and trunk reactance. RBC aggregation “M” is best correlated to arm reactance at 5 kHz but also to most measurements of segmental impedance (28 correlations found). RBC aggregation “M1” is best correlated to arm reactance at 5 kHz and to 19 other impedance measurements. A predictive equation for “M” from the mean between the two arm reactances at 5 kHz (maXc5) is found: M = 2.1845maXc5-23.958 (r  = 0.665, p  < 0.001) that provides a satisfactory Bland-Altman plot (mean difference: 0.000524 range [–1.6;+1.6]. This study suggests that previously reported correlations between BIA and viscosity factors were not spurious, and that in a narrow cylinder such as the arm the structure of circulating blood (hematocrit, red cell aggregation) may influence the passage of an electric current by increasing reactance. Show more

Keywords: Segmental bioelectrical impedance, hematocrit, myrenne aggregometer, red blood cell aggregation, electrical conductance, light transmission

DOI: 10.3233/CH-168041

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 603-611, 2016

Authors: Stoltz, J.-F. | Bensoussan, D. | De Isla, N. | Zhang, L. | Han, Z. | Magdalou, J. | Huselstein, C. | Ye, J.S. | Leballe, B. | Decot, V. | Reppel, L.

Article Type: Research Article

Abstract: Most human tissues do not regenerate spontaneously, which is why “cell therapy” are promising alternative treatments. The Principe is simple: patients’ or donors’ cells are collected and introduced into the injured tissues or organs directly or in a porous 3D material, with or without modification of their properties. This concept of regenerative medicine is an emerging field which can be defined as “the way to improve health and quality of life by restoring, maintaining, or enhancing tissue and organ functions ”. There is an extraordinarily wide range of opportunities for clinical applications: artheropathies, diabetes, cartilage defects, bone repair, …burns, livers or bladder regeneration, organs reconstruction (lung, heart, liver ...) neurodegenerative disorders, sepsis ...   Different stem cells (SC) with different potential can be used and characterised (totipotent, mesenchymal of different origins, especially those present in tissues...). Today it is undeniable that cells like bone marrow, adipose tissue or Wharton Jelly stem cells, are of potential interest for clinical applications because they are easily separated and prepared and no ethical problems are involved in their use. In this paper some potential clinical applications in the vascular field are considered: peripheral arteriopathy in diabetic patients, cardiac insufficiency, traitment of erectile dysfunction, or organ regeneration with liver as example. But the regeneration of tissue or organ is and will remain a challenge for the future development of cell therapy. Many problems remain to be solved that could lead to the development of innovative strategies to facilitate cell differentiation, increase the yield of cells and ensure a standardised product, overcome the risks of teratogenic effects and/or immune reactions, enable grafting via direct cell or biotissue transplantation and avoid legal issues involved in national regulations. Show more

DOI: 10.3233/CH-168036

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 613-633, 2016

Authors: Tikhomirova, Irina | Petrochenko, Elena | Malysheva, Yulia | Ryabov, Mihail | Kislov, Nikolay

Article Type: Research Article

Abstract: Cancer progression is associated with activation of blood coagulation. Blood coagulation process, platelet hemostasis and hemorheological properties were evaluated in patients with solid tumors (n  = 27) before and after surgery and in healthy control (n  = 20). The main features of blood coagulation process in cancer patients were elevated intensity and shortened period of contact phase of coagulation and inhibited fibrinolysis stage. Such prothrombotic state was fixed before surgery as well as in early postoperative period in spite of preventing thromboprophylactic treatment. Platelets depletion within the high level of spontaneous and ADP-induced platelet aggregation was fixed in cancer. The main cause …of blood viscosity decrease in cancer patients was dramatic fall of Hct, because blood viscosity adjusted by Hct 40% was increased owing to the rise of plasma viscosity and substantially worsened RBC microrheological properties. The results of our study indicated close correlation between hemorheological and hemostasis parameters; these interrelations were more numerous and strong in cancer. In cancer patients the combination of a high aggregation activity of platelets, reduced number of erythrocytes (Hct), an increase of RBC aggregation and plasma viscosity caused impairment of blood oxygen transportation efficacy that provoke hypoxia in the microcirculation favoring thrombosis, settlement of tumor and metastasis. Show more

Keywords: Hemorheology, blood coagulation, platelet hemostasis, cancer, surgery

DOI: 10.3233/CH-168037

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 635-644, 2016

Authors: das Graças Coelho de Souza, Maria | Kraemer-Aguiar, Luiz Guilherme | Bouskela, Eliete

Article Type: Research Article

Abstract: Obesity is a crescent epidemic in the world, affecting more than half a billion of adults worldwide. Obesity is associated to main cardiovascular risk factors, such as insulin resistance, type 2 diabetes mellitus, high blood pressure and dyslipidemia. The excessive adiposity causes a dysregulation of adipokines secretion by adipose tissue, upregulating the expression of pro-inflammatory adipokines and downregulating the anti-inflammatory ones. This scenario contributes for the appearance of atherosclerosis. Since endothelium dysfunction is considered the earliest known marker of the atherosclerotic process, several methods to assess precociously the manifestations of endothelial dysfunction in microvessels, such as venous occlusion plethysmography, laser …Doppler flowmetry and nailfold videocapillaroscopy, have been developed. Clinical and experimental studies have shown an impairment of microvascular function, capillary rarefaction and increase in inflammatory status in obesity and the introduction of lifestyle modifications, mainly physical activity and diet, constitute effective interventions to restore microvascular function in obesity. Show more

Keywords: Obesity, adipokines, inflammation, endothelial dysfunction, microvascular function assessment, cardiovascular risk

DOI: 10.3233/CH-168018

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 645-654, 2016

Authors: Lehmann, Christian | Fisher, Nicholas B. | Tugwell, Barna | Szczesniak, Anna | Kelly, Mel | Zhou, Juan

Article Type: Research Article

Abstract: BACKGROUND: Destruction of the insulin-producing beta cells in type 1 diabetes (T1D) is induced by invasion of immune cells causing pancreatic inflammation. Cannabidiol (CBD), a phytocannabinoid, derived from the plant, Cannabis sativa, was shown to lower the incidence of diabetes in non-obese diabetic (NOD) mice, an animal model of spontaneous T1D development. OBJECTIVE: The goal of this study was to investigate the impact of experimental CBD treatment on early pancreatic inflammation in T1D by intravital microscopy (IVM) in NOD mice. METHODS: Seven-week-old female NOD mice were prophylactically administered daily 5 mg/kg CBD or control vehicle …i.p. five times weekly for ten weeks. Animals underwent IVM following confirmation of T1D diagnosis by blood glucose testing. Leukocyte activation and functional capillary density (FCD) were quantified via IVM. RESULTS: CBD-treated NOD mice developed T1D later and showed significantly reduced leukocyte activation and increased FCD in the pancreatic microcirculation. CONCLUSIONS: Experimental CBD treatment reduced markers of inflammation in the microcirculation of the pancreas studied by intravital microscopy. Show more

Keywords: Type 1 diabetes, inflammation, intravital microscopy, leukocyte adherence, functional capillary density, cytokines, adhesion molecules

DOI: 10.3233/CH-168021

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 655-662, 2016

Authors: Lenasi, Helena | Klonizakis, Markos

Article Type: Research Article

Abstract: Diabetes mellitus (DM) is associated with cardiovascular complications. Impairment of glycemic control induces noxious glycations, an increase in oxydative stress and dearangement of various metabolic pathways. DM leads to dysfunction of micro- and macrovessels, connected to metabolic, endothelial and autonomic nervous system. Thus, assessing vascular reactivity might be one of the clinical tools to evaluate the impact of harmful effects of DM and potential benefit of treatment; skin and skeletal muscle microcirculation have usually been tested. Physical exercise improves vascular dysfunction through various mechanisms, and is regarded as an additional effective treatment strategy of DM as it positively impacts glycemic …control, improves insulin sensitivity and glucose uptake in the target tissues, thus affecting glucose and lipid metabolism, and increases the endothelium dependent vasodilation. Yet, not all patients respond in the same way so titrating the exercise type individualy would be desirable. Resistance training has, apart from aerobic one, been shown to positively correlate to glycemic control, and improve vascular reactivity. It has been prescribed in various forms or in combination with aerobic training. This review would assess the impact of different modes of exercise, the mechanisms involved, and its potential positive and negative effects on treating patients with Type I and Type II DM, focusing on the recent literature. Show more

Keywords: Diabetes, exercise, aerobic training, resistance training, high intensity interval training, microcirculation, laser Doppler fluxmetry

DOI: 10.3233/CH-168022

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 663-678, 2016

Authors: Carelli-Alinovi, Cristiana | Dinarelli, Simone | Girasole, Marco | Misiti, Francesco

Article Type: Research Article

Abstract: Our attention is focused on the study of a new model based on the red blood cell (RBC) and on its interaction with amyloid beta peptide 1-42 (Aβ). RBC are highly deformable to assist blood flow in the microcirculation. For this reasons RBC abnormalities could contribute to Alzheimer’s disease (AD) by obstructing oxygen delivery to brain, causing hypoxia. In our work, considering that RBC membrane contains, among blood elements, higher acetylcholinesterase (AChE) levels, we can assume that in blood occurs a mechanism similar to the one which occurs at the neuronal level leading to an increase of Aβ toxicity mediated …by its binding with AChE, located on the RBC external face. Furthermore, since mechanical properties of RBC membrane are regulated by a number of molecular components of signalling and/or regulatory pathways, of these, particular interest has been addressed toward Nitric Oxide (NO) metabolism, due to its dependence to AChE. Show more

Keywords: Amyloid beta peptide, red blood cell, nitric oxide synthase, acetylcholinesterase, NO metabolites, Alzheimer disease

DOI: 10.3233/CH-168047

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 679-687, 2016

Authors: Pfister, Karin | Kasprzak, Piotr M. | Jung, Ernst M. | Müller-Wille, René | Wohlgemuth, Walter | Kopp, Reinhard | Schierling, Wilma

Article Type: Research Article

Abstract: PURPOSE: To evaluate the organ microvascularization after operative versus endovascular treatment of visceral artery aneurysms (VAAs) by contrast-enhanced ultrasound (CEUS) and colour-coded duplex sonography (CCDS). METHOD AND MATERIALS : Between April 1995 to January 2016, 168 patients (78 males, 90 females; median age: 62 years) were diagnosed with VAAs at our hospital site. 60/168 patients (36%) fulfilled treatment criteria and had either open (29/60, 48%) or endovascular (31/60, 52%) aneurysm repair. Patients’ characteristics and presentations were consecutively reviewed. Technical success and organ microvascularization were determined by CCDS/CEUS and correlated to computed tomography angiography (CTA) or magnetic resonance imaging …(MRI). RESULTS: 18/60 patients (30%) presented with acute bleeding. 16/18 emergency patients (89%) were treated by endovascular means. After emergency treatment, two patients showed segmental liver malperfusion by CEUS and CTA. One small bowel resection had to be performed. 42/60 patients (70%) were electively treated. 27/42 patients (64%) had open and 15/42 (36%) endovascular aneurysm repair. There were no liver or bowel infarctions after elective treatment of hepatic or mesenteric artery aneurysms (n  = 13) in CCDS/CEUS and in CTA. Treatment of patients with splenic or renal artery aneurysms led to partial or complete organ loss in 42% (8/19) after operative and in 50% (5/10) after endovascular treatment (p  < 0.05). CONCLUSION: The endovascular approach is the preferred therapeutic option in emergency to control bleeding. In contrast to hepatic or mesenteric procedures, patients for elective splenic or renal artery aneurysm repair have to be evaluated very carefully because of a high rate of partial or complete organ loss demonstrated by CEUS – either after open or endovascular aneurysm repair. Show more

Keywords: Visceral artery aneurysms, open repair, endovascular treatment, contrast-enhanced ultrasound, organ microvascularization

DOI: 10.3233/CH-168003

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 689-698, 2016

Authors: Schulz, Christian | Vukićević, Radovan | Krüger-Genge, Anne | Neffe, Axel T. | Lendlein, Andreas | Jung, Friedrich

Article Type: Research Article

Abstract: The formation of a functionally-confluent and shear-resistant endothelial cell (EC) monolayer on cardiovascular implants is a promising strategy to prevent thrombogenic processes after implantation. On the basis of existing studies with arterial endothelial cells adhering after two hours on gelatin-based hydrogels in marked higher numbers compared to tissue culture plates, we hypothesized that also venous endothelial cells (HUVEC) should be able to adhere and form an endothelial monolayer on these hydrogels after days. Furthermore, variation of the hydrogel composition, which slightly influences the materials elasticity and even more the degradation behaviour, should have no considerable effect on HUVEC. Therefore, the …monolayer formation and shear resistance of HUVEC were explored on two gelatin-based hydrogels differing in their elasticity (Young’s moduli between 35 and 55 kPa) in comparison to a positive control (HUVEC on glass cover slips) and a negative control (HUVEC on glass cover slips activated with interleukin-1β) after 9 days of culturing. HUVEC density after 9 days of culturing under static conditions was lower on the hydrogels compared to both controls (p  < 0.05 each). On G10_LNCO8 slightly more EC adhered than on G10_LNCO5. Staining of the actin cytoskeleton and VE-cadherin revealed a pronounced cell-substrate interaction while the cell-cell interaction was comparable to the controls (HUVEC on glass). The secretion of vasoactive and inflammatory mediators did not differ between the hydrogels and the controls. Adherent HUVEC seeded on the hydrogels were able to resist physiological shear forces and the release of cyto- and chemokines in response to the shear forces did not differ from controls (HUVEC on glass). Therefore, both gelatin-based hydrogels are a suitable substrate for EC and a promising candidate for cardiovascular applications. Show more

Keywords: Endothelial cells, biomaterial, gelatin, hydrogel, shear stress

DOI: 10.3233/CH-168007

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 699-710, 2016

Authors: Zimmermann, H. | Rübenthaler, J. | Paprottka, P. | Paprottka, K.J. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: Currently methods to reduce radiation and contrast media application in endovascular repair of aortic aneurysms (EVAR) are investigated. First positive results for real-time contrast medium–enhanced ultrasonography (CEUS) guided endovascular aortic repair have been reported. A combination with image fusion of CEUS and preoperative multi-slice computed tomography (MS-CT) might offer added safety regarding stent-graft positioning and sealing of the landing zones. EVAR was performed in a patient with an asymptomatic infrarenal aortic aneurysm and a penetrating aortic ulcer in the neck region. The precise placement of the stent-graft was performed with CEUS using image fusion and native intraprocedural angiographic fluoroscopy and confirmed with …digital subtraction angiography (DSA) using iondinated contrast media. At follow-up, CEUS was used to exclude endoleaks and stent-graft failure or malposition. The precise CEUS-guided placement of the stent-graft was technically successful. No artifacts due to electrical noise and metallic parts of the operating table and surgical instruments occurred. The amount of iodinated contrast media was reduced as intraoperative follow-up was performed using CEUS. CEUS with image fusion combined with intraprocedural angiographic fluoroscopy enables accurate stent-graft placement without use of any nephrotoxic contrast media. This allows EVAR in patients with renal insufficiency or allergic reactions to contrast media. Show more

DOI: 10.3233/CH-168045

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 711-719, 2016

Authors: Marcon, J. | Trottmann, M. | Rübenthaler, J. | Stief, C.G. | Reiser, M.F. | Clevert, D.A.

Article Type: Research Article

Abstract: INTRODUCTION: Shear wave elastography (SWE) is a recent technique in the assessment of tissue elasticity. Different elastography techniques have been described over the years. Acoustic Radiation Force Impulse Imaging (ARFI) uses mechanical excitation of tissue to create detectable shear waves, a higher shear wave velocity being associated with an increased tissue stiffness. The Virtual Touch Tissue Imaging Quantification (VTIQ) method uses a mechanical push pulse as well, additionally creating a colour-coded map, in which tissue stiffness can be measured within a stored map on the ultrasound device after measurement. ARFI has been used in determining standard …values in testes of a healthy study collective, VTIQ has already been used in the evaluation of unclear scrotal masses. Both techniques allow an operator-independent examination without application of mechanical pressure. The aim of this study was to determine whether there is a statistically significant difference between shear wave velocity values of both techniques in a healthy collective. MATERIAL AND METHODS: Twenty patients without known testicular pathology underwent standard B-mode sonography and additional shear wave elastography in the ARFI mode as well as the VTIQ technique of both testes using the Siemens Acuson S2000™ and S3000™ ultrasound devices (Siemens HealthCare, Erlangen, Germany). Measurements of shear wave velocity were performed in the upper pole, the central portion and the lower pole separately for each testis. Values were described in m/s. Statistical evaluation was performed using paired t -test analysis. RESULTS: We measured a mean shear wave velocity of 0.81 m/s using ARFI and 1.07 m/s with VTIQ. Shear wave velocities determined by VTIQ were all significantly higher than values gained in the ARFI mode. (p  < 0.001 to p  = 0.007). Values were between 0.22 and 0.29 m/s higher, when the examination was performed using VTIQ. CONCLUSION: ARFI and VTIQ elastography modes both proved to be feasible techniques in the assessment of testicular tissue elasticity. Consideration of higher values for VTIQ is important, when different elastography measurement results are compared, especially for the application of devices in a clinical setting, e.g. in the work-up of scrotal masses. A calculable factor for a comparison between both devices is desirable, but to be further assessed in largerstudies. Show more

Keywords: Testis, ARFI, VTIQ, shear wave elastography, ultrasonography

DOI: 10.3233/CH-168052

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 721-728, 2016

Authors: Trottmann, M. | Rübenthaler, J. | Marcon, J. | Stief, C.G. | Reiser, M.F. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To investigate the difference of standard values of Supersonic shear imaging (SSI) and Acoustic Radiation Force Impulse (ARFI) technique in the evaluation of testicular tissue stiffness in vivo . MATERIALS AND METHODS: 58 healthy male testes were examined using B-mode sonography and ARFI and SSI. B-mode sonography was performed in order to scan the testis for pathologies followed by performance of real-time elastography in three predefined areas (upper pole, central portion and lower pole) using the SuperSonic® Aixplorer ultrasound device (SuperSonic Imagine, Aix-en-Provence, France). Afterwards a second assessment of the same testicular regions by elastography …followed using the ARFI technique of the Siemens Acuson 2000™ ultrasound device (Siemens Health Care, Germany). Values of shear wave velocity were described in m/s. Parameters of elastography techniques were compared using paired sample t -test. RESULTS: The values of SSI were all significantly higher in all measured areas compared to ARFI (p  < 0.001 to p  = 0.015). Quantitatively there was a higher mean SSI wave velocity value of 1,1 compared to 0.8 m/s measured by ARFI. CONCLUSION: SSI values are significantly higher than ARFI values when measuring the stiffness of testicular tissue and should only be compared with caution. Show more

Keywords: Testis, shear-wave elastography, ultrasonography

DOI: 10.3233/CH-168039

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 729-733, 2016

Authors: Platz Batista da Silva, N. | Schauer, M. | Hornung, M. | Lang, S. | Beyer, L.P. | Wiesinger, I. | Stroszczynski, C. | Jung, E.M.

Article Type: Research Article

Abstract: OBJECTIVE: To evaluate the efficacy of strain elastography (SE) using semi-quantitative measurement methods compared to constrast enhanced ultrasound during liver tumor surgery (Io-CEUS) for dignity assessment of focal liver lesions(FLL). MATERIAL AND METHODS: Prospective data acquisition and retrospective analysis of US data of 100 patients (116 lesions) who underwent liver tumor surgery between 10/2010 and 03/2016. Retrospective reading of SE color patterns was performed establishing groups depending on dominant color (>50% blue = stiff, inhomogenous, >50% yellow/red/green = soft tissue). Semi-quantitative analysis was performed by Q-analysis based on a scale from 0 (soft) to 6 (stiff). 2 ROIs were placed centrally, …5 ROIs in the lesion’s surrounding tissue. Io-CEUS was performed by bolus injection of 5–10 ml sulphurhexaflourid microbubbles evaluating wash-in- and -out- kinetics in arterial, portal venous and late phase. Histopathology after surgical resection served as goldstandard. RESULTS: 100 patients (m: 65, f: 35, mean age 60.5 years) with 116 liver lesions were included. Lesion’s size ranged from 0.5 to 8.4 cm (mean 2.42 cm SD±1.44 cm). Postoperative histology showed 105 malignant and 11 benign lesions. Semi-quantitative analysis showed central indurations of >2.5 in 76/105 cases suggesting malignancy. 7 benign lesions displayed no central indurations correctly characterized benign by SE. ROC-analysis and Youden index showed a sensitivity of 72.4% and specificity of 63.6% assuming a cut-off of 2.5. Io-CEUS correctly characterized 103/105 as malignant. Sensitivity was 98%, specificity 72.7%. CONCLUSION: Strain elastography is a valuable tool for non-invasive characterization of FLLs. Semi-quantitative intratumoral stiffness values of >2.5 suggested malignancy. However, sensitivity of Io-CEUS in detecting malignant lesions was higher compared to SE. In conclusion SE should be considered for routine use during intraoperative US in addition to Io-CEUS for optimization of curative liver surgery. Show more

Keywords: Ultrasound, elastography, surgery, CEUS, strain elastography

DOI: 10.3233/CH-168029

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 735-745, 2016

Authors: Wiesinger, I. | Kroiss, E. | Zausig, N. | Hornung, M. | Zeman, F. | Stroszczynski, C. | Jung, E.M.

Article Type: Research Article

Abstract: AIM: To determine different perfusion characteristics of histo-pathologically proven adenomas and carcinomas of the thyroid gland with CEUS and perfusion software. MATERIAL AND METHODS: Retrospective perfusion analysis of 25 patients with carcinomas and 41 cases of adenomas of the thyroid gland (30 males, 36 females; aged 18 – 85 years, mean 56 years). All cases were histologically analyzed. Perfusion analysis was independently performed using external perfusion software (VueBox® ). TTP, mTT, Peak and Rise time were calculated. RESULTS: Lesions’ sizes ranged from 0.2 to 10.2 cm in carcinomas (mean 2.18 cm), and from 0.6 to 5.0 cm in …adenomas (mean 2.25 cm). In 20 out of 25 carcinomas that were evaluated with CEUS, a complete wash-out in the late venous phase was found. Adenomas showed wash-out at the border. Perfusion analysis in VueBox® revealed some parameters which tend to show differences between adenomas and carcinomas, however did not reach the level of significance. Median Peak in carcinomas was highest at the margins (2945 rU), and lowest in the surroundings (1110 rU). Mean Transit Time (mTT) values showed no differences between center, margin and surrounding. In adenomas healthy tissue showed higher mTT values compared to the center (24.6 vs. 20.7 sec). Median Peak was highest in the surrounding tissue and lowest in the margins (1999 vs. 1129 rU). No statistical differences could be found in the comparisons. CONCLUSION: CEUS with perfusion analysis offers new possibilities for the dynamic evaluation of micro-vascularization in thyroid adenomas and carcinomas. Using VueBox® the perfusion analysis of the arterial phase provides new parameters that help determine a lesion’s malignancy or benignity. However a final assessment regarding malignancy and benignity of thyroid lesions using only CEUS and perfusion analysis of the arterial phase is not yet possible. Show more

Keywords: Thyroid, CEUS, perfusion, micro-vascularization

DOI: 10.3233/CH-168044

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 747-755, 2016

Authors: Rübenthaler, J. | Paprottka, K. | Marcon, J. | Hameister, E. | Hoffmann, K. | Joiko, N. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To compare the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI) in the evaluation of unclear renal lesions to the histopathological outcome. MATERIALS AND METHODS: A total of 36 patients with a single unclear solid renal lesion with initial imaging studies between 2005 and 2015 were included. CEUS and MRI were used for determining malignancy or benignancy and initial findings were correlated with the histopathological outcome. Out of the 36 renal masses a total of 28 lesions were malignant (77.8%) and 8 were found to be benign (22.2%). Diagnostic accuracy was testes …by using the histopathological diagnosis as the gold standard. RESULTS: CEUS showed a sensitivity of 96.4%, a specificity of 100.0%, a positive predictive value (PPV) of 100.0% and a negative predictive value (NPV) of 88,9%. MRI showed a sensitivity of 96.4%, a specificity of 75.0%, a PPV of 93.1% and a NPV of 85.7%. Out of the 28 malignant lesions a total of 18 clear cell renal carcinomas, 6 papillary renal cell carcinomas and 4 other malignant lesions, e.g. metastases, were diagnosed. Out of the 8 benign lesions a total 3 angiomyolipomas, 2 oncocytomas, 1 benign renal cyst and 2 other benign lesions, e.g. renal adenomas were diagnosed. Using CEUS, 1 lesion was falsely identified as benign. Using MRI, 2 lesions were falsely identified as benign and 1 lesion was falsely identified as malignant. CONCLUSION: CEUS is an useful method which can be additionally used to clinically differentiate between malignant and benign renal lesions. CEUS shows a comparable sensitivity, specificity, PPV and NPV to MRI. In daily clinical routine, patients with contraindications for other imaging modalities can particularly benefit using this method. Show more

Keywords: Contrast-enhanced ultrasound (CEUS), magnetic resonance imaging (MRI), solid renal lesions

DOI: 10.3233/CH-168034

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 757-763, 2016

Authors: Nemeth, Norbert | Peto, Katalin | Deak, Adam | Sogor, Viktoria | Varga, Gabor | Tanczos, Bence | Balog, Klaudia | Csiszko, Adrienn | Godo, Zoltan | Szentkereszty, Zsolt

Article Type: Research Article

Abstract: BACKGROUND: Abdominal compartment syndrome (ACS) is a life-threatening condition, of which pathomechanism hasn’t been completely clarified, yet. Furthermore, surgical therapy still needs optimization. OBJECTIVE: We aimed to investigate microcirculatory and micro-rheological alterations in ACS, using various temporary abdominal closure methods, including three settings of vacuum-assisted closure technique (negative pressure wound therapy, NPWT). METHODS: On anesthetized pigs, by intraabdominally placed and filled-up silicone bags, intraabdominal pressure at 30 mmHg was maintained for 3 hours, and afterwards, decompressive laparotomy happened. In different experimental groups Bogota-bag or Vivano abdominal sets were applied (–50, –100, –150 mmHg) for 2 hours. Pressure monitoring was …done by implanted sensors, hemorheological parameters were determined, and laser Doppler flowmetry tests were performed on the surface of intraabdominal organs. RESULTS: Treatment with Bogota-bag and –150 mmHg vacuum increased erythrocyte aggregation, while deformability declined. Blood viscosity increased after treatment with –150 mmHg vacuum. The microcirculatory parameters of the NPWT groups were better in small intestine. CONCLUSIONS: ACS resulted in impairment of macro- and micro-rheological parameters and abdominal organs’ microcirculation. All of the used techniques improved the results, however, applying Bogota-bag or –150 mmHg vacuum set showed worse microcirculatory and micro-rheological data than the settings at –100 or –50 mmHg. Show more

Keywords: Abdominal compartment syndrome, negative pressure wound therapy, microcirculation, hemorheology

DOI: 10.3233/CH-168027

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 765-775, 2016

Authors: Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Raynaud de Mauverger, Eric

Article Type: Research Article

Abstract: The hemorheological theory of optimal hematocrit suggests that the best value of hematocrit (hct) should be that which results in the highest value of the hematocrit/viscosity (h/η) ratio. Trained athletes compared to sedentary subjects have a lower hct, but a higher h/η, and endurance training reduces the discrepancy between the actual hct and the ⪡ideal⪢ hct that can be predicted with a theoretical curve of h/η vs hct constructed with Quemada’s model. In this study we investigated what becomes this homeostasis of h/η and hct during acute exercise in 19 athletes performing a 25 min exercise test. VO2max is …negatively correlated to resting hct and positively correlated to discrepancy between actual and ideal resting hct which is correlated to the maximal rise in hct during exercise. Predicted and actual values of the h/η were fairly correlated (r  = 0.970 p  < 0.001) but the actual value was lower at rest and this discrepancy vanished at 25 min exercise. Exercise-induced decrease in discrepancy between actual and theoretical h/η was negatively correlated with the score of overtraining. All these findings suggest that h/η is a regulated parameter and that its model-predicted ⪡optimal⪢ values yield a ⪡theoretical optimal⪢ hct which is close to the actual value and even closer when athletes are well trained. In addition, acute exercise sets h/η closer from its predicted ideal value and this adaptation is impaired when athletes quote elevated scores on the overtraining questionnaire. Show more

Keywords: Blood viscosity, hematocrit, exercise, erythrocyte deformability, hematocrit/viscosity ratio

DOI: 10.3233/CH-168012

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 777-787, 2016

Authors: Brun, Jean-Frédéric | Boulot, Pierre | Varlet-Marie, Emmanuelle

Article Type: Research Article

Abstract: Physiological studies on fetal blood in narrow glass tubes have suggested that fetal optimal hematocrit (hct) might be as high as 60%. A theoretical ‘ideal’ hct can also be predicted with a theoretical curve of hematocrit/viscosity (h/η ) ratio vs hct constructed with Quemada’s model. We used the database of one of our previous papers on fetal hemorheology to reinterpret its results with this concept. A series of 28 intrauterine cord punctures (between 19 and 33 weeks gestation) with doppler measurements of resistance in umbilical arteries was studied. The theoretical ‘optimal hematocrit’ was well correlated to actual (r  = 0.857, p  < 0.01) but …systematically lower (Bland-Altman plot +12.1[8.52–15.7]) than the actual one. Umbilical artery resistance index is correlated with actual hematocrit (r  = 0.407, p  < 0.05), the discrepancy between ideal and actual (r  = – 0.542, p  < 0.05) but not predicted ideal hematocrit, suggesting that the discrepancy between ideal and actual may reflect an adaptative decrease aiming at reducing vascular resistance. These findings indicate that prediction of ideal hematocrit with Quemada’s equation makes sense in fetal blood, and suggest that a ‘viscoregulatory mechanism’ maintains hematocrit below this theoretical value in order to avoid excess vascular resistance. Show more

Keywords: Blood viscosity, hematocrit, exercise, fetus, erythrocyte deformability

DOI: 10.3233/CH-168016

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 789-797, 2016

Authors: Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Fédou, Christine | Raynaud de Mauverger, Eric

Article Type: Research Article

Abstract: We investigated to what extent a prediction of the ‘ideal’ hematocrit based on individual hemorheological profile with an equation of viscosity is relevant in trained athletes, and how the agreement between theoretical and actual values is modified by changes in training volume and performance. Elite soccer players (national level: 18–32 yr, weight 61–83 kg, body mass index 20.9–25.8 kg/m2 ) were seen twice at one year interval. Hemorheologic parameters were measured with the MT90 viscometer and the Myrenne aggregometer the theoretical bell-shaped curve of hematocrit/viscosity ratio as a function of hematocrit was reconstructed with Quemada’s equation using actual plasma viscosity and red cell rigidity to …predict hematocrit/viscosity at various hematocrit levels. RBC aggregation is correlated at baseline with fat mass (M1 = 0.552 p  < 0.02) and changes in aggregation are related to changes in fat mass (M = 0.652, p  < 0.05; M1 = 0.647, p  < 0.05). Predicted and actual hematocrit are correlated (r  = 0.644, p  < 0.05) but exhibit discrepancies (mean difference –1% range [3.24 to 1.24]) and those discrepancies are inversely correlated to the level of predicted hematocrit (r  = –0.912, p  < 0.01), to systolic blood pressure (r  = –0.626, p  < 0.05), and to the overtraining score (r  = –0.693, p  < 0.05). After one year changes in hematocrit are a close reflect of the change in training volume (r  = –0.877, p  < 0.01) but are not correlated to fitness changes. Therefore in these athletes i) systemic hematocrit is close to its predicted ‘ideal value”, suggesting the accuracy of the prediction; ii) red cell aggregation is correlated to fat mass even in nonobese subjects; iii) hematocrit is lower than predicted by the model when markers of sympathetic tone (systolic blood pressure, overtraining score) are increased; iv) weekly training volume appears the main determinant of the reduction of hematocrit. Show more

Keywords: Exercise, soccer, hematocrit/viscosity ratio, hemorheology, erythrocyte aggregation

DOI: 10.3233/CH-168014

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 799-808, 2016

Authors: Joré, Céline | Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle

Article Type: Research Article

Abstract: Erythropoietin (EPO) is a major regulator of blood viscosity. Its long lasting action analogue methoxy polyethylene glycol-epoetin-β (MIRCERA® ) seems to be also employed in modern doping. We took the opportunity of a study aiming at developing a detection of recent MIRCERATM injection in the context of doping detection to assess the effects of this EPO analogue on red blood cells (RBC) aggregation. A single dose 200 μg of MIRCERA® was injected to 10 male volunteers and blood samplings were drawn over 24 days. After injection a decrease in mean corpuscular volume at day 2 (p  < 0.01) and day 10 (p  < 0.02), a rise …in reticulocyte count (p  < 0.001) between day 4 and day 17 and a decrease in ferritin a day 5 (p  < 0.05) was observed. Hemoglobin decreased at day 4 (p  < 0.005). Hematocrit was unchanged. There was a dramatic (+67%) increase in RBC aggregation index “M” (from 9.49±1.01 to 17.66±1.8, p  < 0.01). A decrease in systolic blood pressure was observed during the period from day 4 to day 17 (at day 10: –11.90±2.28 mmHg, p  < 0.001; at day 17: –15.80±2.83, p  < 0.001). There was also a decrease in diastolic blood pressure, mean and pulse pressure. Correlations between this decrease in blood pressure and “M” did not reach significance but pulse pressure was positively correlated to “M” (r  = 0.743, p  < 0.05). These data show that the long acting erythropoietin analogue MIRCERA® strongly increases RBC aggregation parallel to a decrease in blood pressure, but a possible causative link between the two events is not clearly evidenced. Show more

Keywords: Blood viscosity, hematocrit, exercise, erythrocyte deformability

DOI: 10.3233/CH-168015

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 809-816, 2016

Authors: Varlet-Marie, Emmanuelle | Brun, Jean-Frédéric | Raynaud de Mauverger, Eric | Fédou, Christine

Article Type: Research Article

Abstract: We investigated whether the concept of hematocrit/viscosity (h/η ) ratio explains the “paradox of hematocrit in athletes”, by calculating a “theoretical optimal hematocrit” (i.e., associated with the higher h/η value predicted with Quemada’s equation from plasma viscosity, and erythrocyte rigidity index) before and after exercise. 14 rugby players (19–31 yr; weight 65.8–109.2 kg; height 1.7–1.96 m; BMI 21.7–33.1 kg/m2 ) underwent a standardized submaximal exercise session on cycloergometer corresponding to 225 kjoules over 30 min. The rheologic response to exercise was measured with the MT90 viscometer and the Myrenne aggregometer. After exercise there was an increase in whole blood viscosity (p  < 0.05) …and hematocrit (p  < 0.005) and a decrease in h/η ratio (from 14.7±0.34 to 12.9±0.37, p  < 0.005). There was an increase in viscometric RBC rigidity indexes “Tk” and “k” in 9/14 subjects. Predicted and actual h/η are fairly well correlated (preexercise r  = 0.998, p  < 0.001; postexercise r  = 0.985 p  < 0.001) but actual h/η was lower than predicted (preexercise p  = 0.005; postexercise p  = 0.02). This discrepancy between predicted and measured hematocrit was not correlated to dehydration or plasma viscosity but was correlated to red cell rigidity (r  = 0.774, p  < 0.01) and its exercise-induced change (r  = 0.858, p  < 0.01). This study suggests that h/η , although it is not directly correlated to parameters of exercise performance, is precisely regulated during exercise according to the classic concept of “viscoregulation”, and that the prediction of the theoretical optimal values of h/η and hematocrit by models may help to interpret the actual values of these parameters. However, these models need to be more extendedly tested and improved. Show more

Keywords: Blood viscosity, hematocrit, exercise, rugby, erythrocyte deformability

DOI: 10.3233/CH-168042

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 817-826, 2016

Authors: Ahmadizad, Sajad | Bassami, Minoo | Hadian, Mohsen | Eslami, Maryam

Article Type: Research Article

Abstract: BACKGROUND: Acute effects of continuous exercise on the markers of blood fluidity have been addressed in different populations and the changes are intensity related. However, the effect of different high intensity interval exercise (HIIE) on these variables is unclear. OBJECTIVE: This study is designed to determine the effects of two different HIIE with different work/rest ratios but the same energy expenditure on the main determinants of blood fluidity. METHODS: Ten overweight men (age, 26.3±1.7 yrs) completed two HIIE protocols on two separate occasions with one week intervening. The two HIIE encompassed performing: 1) 6 intervals …of 2 min activity at 85% of VO2max interspersed by 2 min active recovery at 30% of VO2max (ratio 1 to 1, HIIE1/1 ), and 2) 6 intervals of 30 s activity at 110% of VO2max interspersed by 4 min active recovery at 40% of VO2max (ratio 1 to 8, HIIE1/8 ). Each exercise trial was followed by 30 min rest. Venous blood samples were obtained before exercise, immediately after exercise and after recovery and analyzed for blood and plasma viscosity, fibrinogen and red blood cell indices. RESULTS: The HIIE1/1 protocol led to higher reduction (P  < 0.01) in plasma volume changes compared to HIIE1/8 (9.9% vs 5.7%). Moreover, increases in blood viscosity, plasma viscosity, hematocrit, RBC count and mean arterial blood pressure observed following HIIE1/1 were significantly (P  < 0.05) higher than HIIE1/8 ; whereas, the changes in fibrinogen concentration neither were significant in response to both trials nor were significantly different between two protocols (P  > 0.05). However, the changes in all variables during exercise were transient and returned to the baseline levels after 30 min recovery. CONCLUSIONS: It is concluded that the HIIE protocol with lower intensity and shorter rest intervals (higher work to rest ratio) clearly results in more physiological strain than HIIE with higher intensity but longer rest intervals (lower work to rest ratio) in overweight individuals, and that the work to rest ratio could be as important as exercise intensity when considering the hemorheological variables during HIIE. Show more

Keywords: Interval exercise, exercise intensity, blood viscosity, fibrinogen

DOI: 10.3233/CH-168009

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 827-835, 2016

Authors: Antonova, N. | Tsiberkin, K. | Podtaev, S. | Paskova, V. | Velcheva, I. | Chaushev, N.

Article Type: Research Article

Abstract: The aim of the study is to investigate the changes of the skin blood flow responses to cold stress in patients with diabetes mellitus type 2 through wavelet analysis of the peripheral skin temperature oscillations and to estimate their relationship with the blood viscosity values. The amplitudes of the skin temperature pulsations (ASTP) were monitored by “Microtest” device (“FM-Diagnostics”, Russia); the whole blood viscosity and the shear stresses were measured by Contraves LS30 viscometer (Switzerland) at a steady flow in 9 healthy subjects and in 30 patients with type 2 diabetes mellitus. Power law and Herschel-Bulkley (HB) equations were applied …to describe the blood rheology. Both models include consistency (k ) and flow index (m ), and the HB also gives the yield stress (τ 0 ). The Spearman rank correlations between these parameters and the ASTP in the frequency ranges, corresponding to the myogenic, neurogenic and endothelial mechanisms of the microcirculation tone regulation were calculated. The ASTP values decreased when the blood viscosity increased. The correlation analysis revealed good ASTP–m (r  > 0.5) and ASTP–k (r  < –0.5) relationships in the endothelial range, while the ASTP–τ 0 correlation was weaker (r ≈–0.4). These correlations became lower for the ASTP during the cold stress. The results prompt manifestation of endothelial dysfunction in patients with type 2 diabetes. Show more

Keywords: Diabetes mellitus type 2, skin temperature oscillations, contralateral cold test, microcircular tone regulation, blood viscosity, hemorheological equations

DOI: 10.3233/CH-168000

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 837-844, 2016

Authors: Jovtchev, S. | Alexandrov, S. | Hristova-Avakumova, N. | Miteva, S. | Traikov, L. | Gerasimova, D. | Stoeff, S.

Article Type: Research Article

Abstract: BACKGROUND: Different colloids are used as a part of solutions for fluid resuscitation and organ preservation: hydroxyethyl starches (HES), dextran (Dx), polyethylene glycols (PEG), polyvinyl pyrrolidone (PVP). Some of the problems associated with their application are addressed to alteration in erythrocyte (ERY) rheology. OBJECTIVE: We intended to estimate in vitro and compare the aggregation power (AP) of these molecules related to ERY interactions. METHODS: Washed human ERY are used during the study. The zeta sedimentation technique is used to quantify the cell aggregation. Zeta sedimentation ratio (ZSR) based indices (AI) are calculated. The hydrodynamic …radius (Rh ) of the polymer molecules is determined using viscometry. RESULTS: For all polymers tested a linear range in the relationship AI – concentration was found. The slope of the calculated line was interpreted as measure of the molecule’s AP. The following ranking was obtained: PEG >PVP >DX >HES. Within the same chemical type of polymer, increasing Rh of the molecules leads to elevated AI. Comparison of the AP of molecules with similar Rh reveals a significant dependence on their chemical nature. CONCLUSIONS: Our results show that molecule’s AP is significantly dependent on their chemical nature – i.e. not only molecular size does matter. Show more

Keywords: Erythrocyte, aggregation, polymer, Zeta sedimentation ratio, hydrodynamic radius

DOI: 10.3233/CH-168019

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 845-851, 2016

Authors: Lee, K. | Priezzhev, A. | Shin, S. | Yaya, F. | Meglinski, I.

Article Type: Research Article

Abstract: BACKGROUND: The novel measure of the red blood cells (RBC) aggregation (RBC-A) – the critical (minimum) shear stress (CSS) to prevent the cells from aggregation was found to be a promising clinically significant parameter. However, the absolute values of this parameter were found to change significantly depending on the shearing geometry (cup-and-bob, cone-plate or microchannel-flow) and have different temperature dependences along with it. The direct confirmation of these dependences aimed to find out the correct values is still pending. OBJECTIVE: In this work, we aim to assess the absolute values of CSS at different temperatures. METHODS: …The single cell level measurements of CSS were performed using optical tweezers. The measurements were carried out in heavily diluted suspensions of RBCs in plasma. RESULTS: The temperature dependent changes in CSS were measured at the points (22 and 38°C), in which the cup-and-bob and cone-plate systems yielded about 1.5-fold different values, while the microchannel-flow system yielded a constant value. The single cell CSS were found to be 362±157 mPa (22°C) and 312±57 mPa (38°C). CONCLUSIONS: Our results prove that the microfluidic-flow approach is reflecting the RBC-A correctly. While the CSS values measured with other systems show the temperature dependent effect of the shearing geometry. Show more

Keywords: Red blood cell, aggregation, critical shear stress, temperature, shearing-geometry, single-cell level measurements, optical tweezers, microfluidic flow

DOI: 10.3233/CH-168020

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 853-857, 2016

Authors: Silva, Marisa | Vargas, Sofia | Coelho, Andreia | Dias, Alexandra | Ferreira, Teresa | Morais, Anabela | Maia, Raquel | Kjöllerström, Paula | Lavinha, João | Faustino, Paula

Article Type: Research Article

Abstract: Sickle cell anemia (SCA) is an autosomal recessive disease caused by the HBB:c.20A>T mutation that leads to hemoglobin S synthesis. The disease presents with high clinical heterogeneity characterized by chronic hemolysis, recurrent episodes of vaso-oclusion and infection. This work aimed to characterize by in silico studies some genetic modulators of severe hemolysis and stroke risk in children with SCA, and understand their consequences at the hemorheological level. Association studies were performed between hemolysis biomarkers as well as the degree of cerebral vasculopathy and the inheritance of several polymorphic regions in genes related with vascular cell adhesion and vascular …tonus in pediatric SCA patients. In silico tools (e.g. MatInspector ) were applied to investigate the main variant consequences. Variants in vascular adhesion molecule-1 (VCAM1 ) gene promoter and endothelial nitric oxide synthase (NOS3 ) gene were significantly associated with higher degree of hemolysis and stroke events. They potentially modify transcription factor binding sites (e.g. VCAM1 rs1409419_T allele may lead to an EVI1 gain) or disturb the corresponding protein structure/function. Our findings emphasize the relevance of genetic variation in modulating the disease severity due to their effect on gene expression or modification of protein biological activities related with sickled erythrocyte/endothelial interactions and consequent hemorheological abnormalities. Show more

Keywords: Sickle cell anemia, VCAM1, NOS3, genetic modulators, in silico analysis

DOI: 10.3233/CH-168048

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 859-866, 2016

Authors: Krüger-Genge, A. | Fuhrmann, R. | Jung, F. | Franke, R.P.

Article Type: Research Article

Abstract: The endothelialization of cardiovascular prostheses is known to improve their haemocompatibility. As such body-foreign materials often do not endothelialize spontaneously. A lot of in vitro studies are ongoing how endothelialization of biomaterials can be improved. In this study the influence of different components of a tissue-typical extracellular matrix (ECM) like laminin, fibronectin or gelatin on the formation of an endothelial cell monolayer and on the shear resistance of adherent cells on these substrates was studied. The study revealed that the density of human venous endothelial cells (HUVEC) monolayers differed markedly between cells grown on a natural ECM and …cells grown on singularized components of an ECM (p  < 0.001). Only HUVEC grown on laminin showed similar densities and a stress fiber pattern comparable to HUVEC grown on the ECM. HUVEC grown on gelatin- or fibronectin-coated coverslips were less firmly attached to the substrate; frequently individual HUVEC and even groups of cells detached. Concluding it seems that coating of implants with laminin supports the formation of shear resistant endothelial cell (EC) monolayer - superior to other ECM components. Show more

Keywords: HUVEC, extracellular matrix, laminin, fibronectin, gelatin

DOI: 10.3233/CH-168051

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 867-874, 2016

Authors: Rozanovic, Martin | Csontos, Csaba | Bogár, Lajos | Szélig, Lívia | Bocskai, Tímea | Kovács, Patrícia | Matancic, Marianna | Miseta, Attila | Loibl, Csaba

Article Type: Research Article

Abstract: BACKGROUND: In polytrauma and burn injury Systemic Inflammatory Response Syndrome (SIRS) develops. SIRS is presented in many hospitalized patients, including those who never develop infection or sepsis. Both in SIRS and sepsis the leukocyte activation occurs. In acute phase reaction leukocytes’ upward flotation i.e. leukocyte antisedimentation rate (LAR) can indicate infectious origin. OBJECTIVE: To evaluate the predictive power of LAR, serum C-reactive protein (CRP) and procalcitonin (PCT) levels regarding mortality risk and development of septic complications. METHODS: In a prospective, observational study, 36 patients were followed for 5 days (T1-T5) after admission to a critical …care unit immediately with severe polytrauma or burn injury. Eleven patients developed septic complications, their LAR, CRP and PCT levels were analyzed before and after 3 days of sepsis was declared. RESULTS: Ten patients died due to septic complications. In survivors LAR at T1 (p  < 0.001) and T2 (p  < 0.001) as well as CRP at T1 (p  < 0.05) were significantly higher compared to controls and non survivors. In septic patients LAR (p  < 0.05) and CRP (p  < 0.05) showed a significant drop one day before sepsis was declared. PCT levels failed to predict this. CONCLUSIONS: Drop in LAR and CRP levels may be warning signs regarding the onset of septic complications after severe polytrauma and burn injury. Show more

Keywords: Mechanical and heat trauma, inflammatory response, leukocyte antisedimentation rate, C-reactive protein, procalcitonin

DOI: 10.3233/CH-168024

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 875-885, 2016

Authors: Paprottka, Karolin J. | Waggershauser, Tobias | Rübenthaler, Johannes | Paprottka, Felix J. | Clevert, Dirk A. | Reiser, Maximilian F. | Paprottka, Philipp M.

Article Type: Research Article

Abstract: OBJECTIVE: To evaluate various embolization particles on their physical properties with special regard on morphological variability and elasticity. METHODS: 8 embolization particles (EmboCept® , Contour SE® Microspheres, Embosphere® Micorspheres 400 μm, 500 μm, 1300 μm, Embozene® Microspheres, DC Beads® , Embozene Tandem® ) were evaluated and graduated from 1–6 microscopically due to morphologic changes in vitro before, during and after their catheter passage by 4 blinded reviewers. To facilitate comparison, microscopic images were provided with a scale. RESULTS: All tested particles showed a homogenous shape and morphology before passage through the …simulation catheter. During the passage all particles were elastically deformable, where necessary. After the catheter passage no loss of basic shape was seen. Changes in size were found in 5/8 particles. Grading of morphologic changes varied between mean value of 1.0 and 3.0. No complete destruction or loss of function was seen. CONCLUSION: All tested embolization particles are, regarding their morphological properties in sense of homogenous shape and deformation after catheter passage, a safe treatment option. Tested in vitro no less of functionality regarding physical properties should be expected. Show more

Keywords: Embolization particles, physical properties, morphology, elasticity, catheter passage

DOI: 10.3233/CH-168002

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 887-898, 2016

Authors: Roch, Toralf | Kratz, Karl | Ma, Nan | Lendlein, Andreas

Article Type: Research Article

Abstract: Although frequently used as implants materials, both polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) are often associated with adverse effects including foreign body responses. Dendritic cells (DC) are crucial for the initiation of immune reactions and could also play a role in foreign body associated inflammations. Therefore, the interaction of DC with PDMS and PTFE was investigated regarding their capacity to induce undesired cell activation. Medical grade PDMS and PTFE films were embedded into polystyrene PS inserts via injection molding to prevent the DC from migrating below the substrate and thereby, interacting not only with the test sample but also with the …culture vessel material. The viability, the expression of co-stimulatory molecules, and the cytokine/chemokine profiles were determined after 24 hours incubation of the DC with PDMS or PTFE. Blank PS inserts and tissue culture polystyrene (TCP) served as reference materials. The viability of DC was not substantially influenced after incubation with PDMS and PTFE. However, both polymers induced DC activation indicated by the upregulation of co-stimulatory molecules. The release profiles of 14 soluble inflammatory mediators showed substantial differences between PDMS, PTFE, PS, and TCP. This study showed the potential of PTFE and PDMS to activate primary human dendritic cells, which could be an explanation for the often observed inflammatory events associated with the implantation of these polymers. Show more

Keywords: Biomaterials, dendritic cells, polydimethylsiloxane, polytetrafluoroethylene, cell culture devices

DOI: 10.3233/CH-168033

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 899-910, 2016

Authors: Ahmadizad, Sajad | Nouri-Habashi, Akbar | Rahmani, Hiwa | Maleki, Majid | Naderi, Nasim | Lotfian, Sara | Salimian, Morteza

Article Type: Research Article

Abstract: BACKGROUND: The effects of high intensity interval training (HIIT) on inflammatory markers and endothelial function have been extensively shown. However, the acute effect of HIIT on platelet activation and function in patients with recent revascularization is unclear. OBJECTIVE: The purpose of present study was to compare the responses of platelet activation (CD62P) and function (platelet aggregation) to high intensity interval exercise (HIIE) and moderate continuous exercise (MCE) in coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI) patients. METHODS: Thirty patients who had CABG or PCI were randomly divided into HIIE, MCE and control …groups. After determining the VO2peak , subjects in the MCE group carried out 30 min of continuous exercise at 60% of VO2peak , whereas, the subjects in HIIE group performed an interval protocol consisted of 8 repetitions of 2 min activity (running on treadmill) at 90% of VO2peak interspersed by 2 min of active recovery between repetitions at 30% of VO2peak .  Subjects in control group were seated and had no activity for the same period of time. Two blood samples were collected before and immediately after exercise and were analyzed for markers of platelet activation and function. RESULTS: Data analyzes revealed that increases in platelet aggregation induced by ADP and corrected for increases in platelet count in response to MCE trial was significantly lower than HIIE group (P  < 0.05). In addition, responses of CD62P to MCE trial was significantly lower compared to HIIE group (P  < 0.05). Changes in plateletcrit and platelet distribution width were significantly different among the three trials where the PCT and PDW following the HIIE were higher than MCE. Platelet count increased significantly (P  < 0.05) by 13% following HIIE trial. CONCLUSIONS: Based on the findings of the present study it could be concluded that the risk of exercise-induced thrombosis is higher during HIIE than MCE in patients with recent revascularization. Show more

Keywords: Interval exercise, acute exercise, platelet aggregation, p-selectin, CD62P

DOI: 10.3233/CH-168010

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 911-919, 2016

Authors: Basarab, M.A. | Basarab, D.A. | Konnova, N.S. | Matsievskiy, D.D. | Matveev, V.A.

Article Type: Research Article

Abstract: OBJECTIVE: The aim of this work was to develop a novel technique for digital processing of Doppler ultrasound blood flow sensor data from noisy blood flow velocity waveforms. METHODS: To evaluate the fluctuating blood flow parameters, various nonlinear dynamics methods and algorithms are often being used. Here, for identification of chaotic and noise components in a fluctuating coronary blood flow, for the first time the Allan variance technique was used. Analysis of different types of noises (White, Brownian, Flicker) was carried out and their strong correlation with fractality of time series (the Hurst exponent) was revealed. …RESULTS: Based on a specialized software realizing the developed technique, numerical experiments with real clinical data were carried out. Recommendations for identification of noisy patterns of coronary blood flow in normal and pathological states were developed. CONCLUSION: The methodology gives us the possibility for the more detailed quantitative and qualitative analysis of a noisy fluctuating blood flow data. Show more

Keywords: Blood flow, Doppler flowmetry, Allan variance, Hurst exponent, nonlinear dynamics, Alavar

DOI: 10.3233/CH-168011

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 921-930, 2016

Authors: Kumar, Reddi K. | Basu, Sayantani | Lemke, Horst-Dieter | Jankowski, Joachim | Kratz, Karl | Lendlein, Andreas | Tetali, Sarada D.

Article Type: Research Article

Abstract: Accumulated uremic toxins like indoxyl sulphate, hippuric acid and p-cresyl sulphates in renal failure patients stimulate proinflammatory effects, and consequently kidney and cardiovascular diseases. Low clearance rate of these uremic toxins from the blood of uremic patients by conventional techniques like hemodialysis is due to their strong covalent albumin binding (greater than 95%) and hydrophobic nature, which led to alternatives like usage of hydrophobic adsorber’s in removing these toxins from the plasma of kidney patients. Polymers like polyethylene, polyurethane, polymethylmethacrylate, cellophane and polytetrafluoroethylene were already in use as substitutes for metal devices as dialysis membranes. Among new synthetic polymers, one …such ideal adsorber material are highly porous microparticles of poly(ether imide) (PEI) with diameters in the range from 50–180μ m and a porosity around 88±2% prepared by a spraying and coagulation process. It is essential to make sure that these synthetic polymers should not evoke any inflammatory or apoptotic response during dialysis. Therefore in our study we evaluated in vitro effect of PEI microparticle extracts in human aortic endothelial cells (HEACs) concerning toxicity, inflammation and apoptosis. No cell toxicity was observed when HAECs were treated with PEI extracts and inflammatory/apoptotic markers were not upregulated in presence of PEI extracts. Our results ensure biocompatibility of PEI particles and further hemocompatibility of particles will be tested. Show more

Keywords: Poly(ether imide) (PEI), biomaterial, inflammation, apoptosis, medical devices, Tumor necrosis factor-alpha(TNF-α)

DOI: 10.3233/CH-168046

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 931-940, 2016

Authors: Tzoneva, Rumiana | Uzunova, Veselina | Apostolova, Sonia | Krüger-Genge, Anne | Neffe, Axel. T. | Jung, Friedrich | Lendlein, Andreas

Article Type: Research Article

Abstract: Angiogenesis is one of the key processes during development, wound healing and tumor formation. Prerequisite for its existence is the presence of endogenous electrical fields (EFs) generated by active ion transport across polarized epithelia and endothelia, and appearance of the transcellular potentials. During angiogenesis cellular factor as endothelial growth factor (VEGF), synthesis of adhesive proteins and membrane metalloproteinases (MMPs) govern the angiogenic response to different external stimuli as biomaterials interactions and/or exogenous EF. Gelatin-based hydrogels with elasticities comparable to human tissues have shown to influence cell behavior as well as cell attachment, protein synthesis, VEGF and MMP’s production after the …application of EF. Gelatin-based matrices with 3 (G10_LNCO3), 5 (G10_LNCO5), and 8 (G10_LNCO8) fold excess of isocyanate groups per mol of amine groups present in gelatin were used. Human umbilical endothelial cells (HUVEC) (Lonza Basel, Switzerland) and highly invasive breast cancer MDA-MB-231 cells (ATCC®HTB-26TM ) were used. For an estimation of the amount of VEGF released from cells a commercially available VEGF ELISA (Thermo Fisher Scientific, Germany) kit was used. Fibronectin (FN) enzyme immunoassay (EIA) was used to analyze the secreted amount of FN by cells seeded on the materials. Secreted MMPs were analyzed by zymography. Gelatin-based hydrogels attracted HUVEC adhesion and diminished the adhesion of MDA-MB-231 cells. The applied direct current (DC) EF induced an almost 5–fold increase in VEGF production by HUVEC seeded on gelatin-based hydrogels, while in contrast, the applied EF decreased the production of VEGF by cancer cells. FN synthesis was elevated in HUVEC cells seeded on gelatin-based materials in comparison to FN synthesis by cancer cells. HUVEC seeded on gelatin hydrogels showed an expression mainly of MMP-2. The application of EF increased the production of MMP-2 in HUVEC seeded on gelatin materials. In contrast, for MDA-MB-231 the production of MMPs on gelatin materials was lower compared to control materials. With the application of EF the levels of MMP-9 decreased but MMP-2 expression raised significantly for gelatin materials. Overall, the results showed that studied gelatin materials suppressed attachment of cancerous cells, as well as suppressed their angiogenic potential revealed by decreased VEGF and MMP production. Thus, this study approved gelatin-based hydrogels with proper elasticity characteristics and different degradation behavior as useful matrices for use in vascular tissue regeneration or in restriction of tumor growth after tumor resection. Show more

Keywords: Angiogenesis, gelatin hydrogels, VEGF production, FN synthesis, MMPs expression

DOI: 10.3233/CH-168040

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 941-949, 2016

Authors: Duarte, Catarina | Napoleão, Patrícia | Freitas, Teresa | Saldanha, Carlota

Article Type: Research Article

Abstract: INTRODUCTION: Acetylcholinesterase (AChE) is located on outer surface of erythrocyte membrane. Gender-related differences in erythrocyte AChE enzyme activity had been verified in young adults. It is also known that binding of acetylcholine (ACh) with AChE on erythrocyte membrane initiates a signal transduction mechanism that stimulates nitric oxide (NO) efflux. AIMS: This ex vivo study was done to compare the amount of NO efflux obtained from erythrocytes of healthy donors in males and females. METHODS: We included 66 gender age-matched healthy donors (40–60 years old). We performed quantification of erythrocyte NO efflux from erythrocytes and …of the membrane AChE enzyme activity. RESULTS: There are no significant differences in NO efflux from erythrocytes between men and women. Regarding AChE enzyme activity values, in this range of age, no differences between genders were obtained. However, the values of AChE enzyme activity in the third quartile of NO efflux values were significantly higher (p  < 0.05) in women than in men. CONCLUSIONS: The efflux of NO from erythrocyte of healthy humans did not change with gender. For the same range of values of NO efflux from erythrocytes, in both gender, it was verified higher values of AChE enzyme activity in women. Show more

Keywords: Gender, erythrocyte, nitric oxide, acetylcholinesterase

DOI: 10.3233/CH-168023

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 951-955, 2016

Authors: Aguiar, Laura | Matos, Andreia | Gil, Ângela | Afonso, Conceição | Almeida, Salomé | Braga, Lígia | Lavinha, João | Kjollerstrom, Paula | Faustino, Paula | Bicho, Manuel | Inácio, Ângela

Article Type: Research Article

Abstract: BACKGROUND: Sickle cell anemia (SCA) is an inherited blood disorder. SCA patients present clinical and hematologic variability that cannot be only explained by the single mutation in the beta-globin gene. Others genetic modifiers and environmental effects are important for the clinical phenotype. SCA patients present arginine deficiency that contributes to a lower nitric oxide (NO) bioactivity. OBJECTIVE: The aim of this work is to determine the association between hematological and biochemical parameters and genetic variants from eNOS gene, in pediatric SCA patients. METHODS: 26 pediatric SCA patients were genotyped using polymerase chain reaction (PCR) …and restriction fragment length polymorphism (RFLP) techniques in three important eNOS gene polymorphisms - rs2070744, rs1799983 and intron 4 VNTR. RESULTS: Results from this study show a significant statistical association between some parameters and genetic variants: an increased reticulocyte count and high serum lactate dehydrogenase levels were associated with both the rs2070744_TT and the rs1799983_GG genotypes at eNOS gene and high levels of neutrophils were associated with the eNOS4a allele at intron 4 VNTR. CONCLUSIONS: Our results reinforce the importance of NO bioactivity in SCA. We presume that NO, and its precursors might be used as therapy to improve the quality of life of SCA patients. Show more

Keywords: Sickle cell anemia, genetic modifiers, nitric oxide

DOI: 10.3233/CH-168008

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 957-963, 2016

Authors: Napoleão, Patrícia | Potapova, Ekaterina | Moleirinho, Sara | Saldanha, Carlota | Messias, António

Article Type: Research Article

Abstract: AIM: Soluble CD40 ligand (sCD40L) has been considered as a marker of thrombosis and inflammation in several diseases, including sepsis. Recent studies challenge this view and point to a role of sCD40L in vascular and endothelial function. An indication of that association in sepsis has not been obtained so far. Therefore, herein we evaluated association between sCD40L and markers of hemorheology and inflammation on context of septic shock. METHODS: Time-changes of sCD40L levels over 72 hours of Intensive Care Unit (ICU) internment were assessed in 22 patients with septic shock and compared with 36 healthy volunteers. Association of sCD40L …levels with erythrocyte deformability and aggregation (as markers of hemorheology), plasma concentrations of haemoglobin (Hb, as markers of endothelial function) and white blood cells (WBC) count (as marker of low-grade inflammation) were assessed in patients with septic shock. RESULTS: At ICU admission, sCD40L concentrations in patients with septic shock were lower (p  = 0.024) than levels of healthy volunteers. However, sCD40L did not change over 72 hours of internment (F = 2.1, p  = 0.137). Soluble CD40L levels in patients with septic shock at ICU admission correlate with concentrations of Hb (r  = 0.61, p  = 0.00) and WBC count (r  = 0.63, p  = 0.00), but not to erythrocyte deformability (r ≥0.157, p ≤0.235) and aggregation (r ≥–0.109, p ≤0.192). CONCLUSIONS: These results seem to highlight a possible association of sCD40L to endothelial function and inflammation in septic shock context. Show more

Keywords: Sepsis, sCD40L, haemoglobin, inflammation, hemorheology

DOI: 10.3233/CH-168026

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 965-970, 2016

Authors: Napoleão, Patrícia | Freitas, Teresa | Saldanha, Carlota

Article Type: Research Article

Abstract: AIMS: Oxidized low density lipoprotein (ox-LDL) has been reported as an inhibitor of nitric oxide (NO)-mediated dilatation in microcirculation. Oxidized LDL effect on NO metabolism of erythrocytes is not known. Therefore, this study aims to evaluate the effect of ox-LDL on erythrocytes NO metabolism. METHODS: The effect of different concentrations of human purified ox-LDL (25, 50 and 100 μg/mL) on NO metabolism was evaluated on blood of healthy subjects. RESULTS: An inhibitory effect of higher concentrations of ox-LDL on erythrocyte NO efflux levels was verified. Concentrations of NO efflux from erythrocytes were lower as consequence …of treatments with 50 μg/mL ox-LDL treatment (1.6±0.27 nM) and 100 μg/mL ox-LDL treatment (1.3±0.22 nM) than control (1.9±0.28 nM). Opposite, ox-LDL incubation has a positive effect on GSNO content of erythrocytes. That effect is proportional to concentrations of ox-LDL treatments (10.8±1.4 nM for 25 μg/mL, 12.9±1.5 nM for 50 μg/mL and 12.1±1.9 nM for 100 μg/mL) and is significant relative to control (8.56±0.76 μM) and ACh (8.9±0.52 μM) aliquots. CONCLUSIONS: Presence of oxidized LDL in erythrocyte NO metabolism induces a decrease of NO efflux amount and an increase on intra-erythrocyte GSNO concentrations. These results suggest a role of ox-LDL in mobilization of NO between NO derivatives molecules in dependence of oxidized LDL concentration. An anti - reactive nitrogene role can be attributed to ox-LDL for its contribution in the erythrocyte scavenged ability for nitric oxide. Show more

Keywords: Oxidized LDL, erythrocyte, nitric oxide, S-nitrosoglutathione

DOI: 10.3233/CH-168025

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 971-975, 2016