Clinical Hemorheology and Microcirculation - Volume 64, issue 1

Authors: Gyawali, Prajwal | Richards, Ross S. | Tinley, Paul | Nwose, Ezekiel Uba | Bwititi, Phillip T.

Article Type: Research Article

Abstract: The present study compares the association of Metabolic Syndrome (MetS) with hemorheological parameters, oxidative stress, inflammation and peripheral arterial disease markers. 100 participants were recruited and participants were divided into three groups on the basis of absence or presence of MetS and its components. Odds ratio for correctly predicting MetS was highest for erythrocyte aggregation followed by erythrocyte deformability. ROC curve analysis demonstrated that all the hemorheological components significantly classified MetS participants. Area Under Curve was higher for the hemorheological parameters (erythrocyte aggregation and erythrocyte deformability) than for the oxidative stress, inflammation and peripheral arterial disease markers. The possibilities of …the hemorheological components to be identified as better cardiovascular risk markers due to their strong association with MetS cannot be precluded from the present findings. Show more

Keywords: Hemorheology, oxidative stress, inflammation, ROC curve

DOI: 10.3233/CH-152033

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 1-5, 2016

Authors: Caimi, G. | Montana, M. | Canino, B. | Calandrino, V. | Lo Presti, R. | Hopps, E.

Article Type: Research Article

Abstract: Considering that obstructive sleep apnea syndrome (OSAS) is usually associated with endothelial dysfunction, atherosclerosis and cardiovascular disorders, our aim was to examine the erythrocyte deformability and the oxidative status in a group of OSAS subjects. We consecutively enrolled 48 subjects with OSAS defined after a 1-night cardiorespiratory sleep study, subsequently subdivided according to the apnea/hypopnea index (AHI) value in two subgroups: Low (L = 21 subjects with AHI<30) and High (H = 27 subjects with AHI>30). We evaluated the erythrocyte deformability, expressed as elongation index (EI) and the parameters of the oxidative status, such as lipid peroxidation (expressed as thiobarbituric …acid-reactive substances – TBARS) and protein oxidation (measured as carbonyl groups – PC). In the entire group and in the two subgroups of OSAS subjects we found a decreased erytrocyte deformability at all shear stresses, not correlated with the plasmatic oxidative stress nor with the polysomnographic parameters. Lipid peroxidation was increased in the whole group and in the H subgroup of OSAS while protein oxidation showed a different trend. As in OSAS the osmotic fragility and the metabolism of the red cells seem to be not impaired, the oxidative damage to the red cell membrane proteins might be responsible for the reduced erythrocyte deformability. This rheological alteration, in addition to the increase in whole blood and plasma viscosity and to the erythrocyte hyperaggregation, could influence the microcircolatory profile in OSAS subjects. Show more

Keywords: Erythrocyte deformability, lipid peroxidation, protein oxidation, OSAS

DOI: 10.3233/CH-152034

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 7-14, 2016

Authors: Fontana, Francesco | Ballestri, Marco | Cappelli, Gianni

Article Type: Research Article

Abstract: Uremic patients undergoing dialysis (HD) present a cardiovascular risk of death 10–20 fold higher than general population, but also kidney transplantation keeps considerable cardiovascular burden. Hemorheologic profile alterations have been described in HD; comprehensive data on kidney transplant recipients (KT) are missing. Aim of our study is to characterize the hemorheological profile in KT, and to compare these data with HD and healthy volunteers (HV). We investigated 47 HV, 90 HD and 108 KT. We confirm hemorheological alterations in HD. KT, when compared to HD, normalizes many parameters: plasma viscosity, whole blood viscosity at 1-Hz and 200-Hz …shear rate, erythrocyte aggregation index and yield stress. KT show a markedly lower erythrocyte deformability (ED). We found no differences among hemorheological parameters between the different classes of immunosuppressive drugs used. In conclusion, HD show various hemorheological defects; this could support the high incidence of cardiovascular complications. KT improves most hemorheological alterations; nevertheless, ED is reduced in KT, maintaining a detrimental injury at microcirculatory level and leading to the progression of fibrosis till to end-stage injury. Impaired ED in KT could also contribute to progression of interstitial fibrosis and tubular atrophy (IF/TA) in grafts. Show more

Keywords: Kidney transplantation, hemorheology, erythrocyte deformability

DOI: 10.3233/CH-152036

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 15-20, 2016

Authors: Tarasev, M. | Chakraborty, S. | Light, L. | Davenport, R.

Article Type: Research Article

Abstract: Susceptibility of red blood cells (RBC) to hemolysis under mechanical stress is represented by RBC mechanical fragility (MF), with different types or intensities of stress potentially emphasizing different perturbations of RBC membranes. RBC membrane mechanics were shown to depend on cell environment, with many details not yet understood. Here, stress was applied to RBC using a bead mill with oscillation up to 50 Hz, over durations up to 50 minutes. MF profiles plot percent lysis upon stresses of progressive durations. Supplementing media with polyethylene glycol (PEG) which interacts with the cell membrane, but not Dextran which does not, resulted in higher …resistance to hemolysis. Albumin, and to a lesser extent fibrinogen and globulins (at physiological concentrations), significantly increased cell ability to withstand mechanical stress versus with un-supplemented buffer solution and with PEG. This is partly due to changes in rheology, per tests done including (PEG) and Dextran, but is mostly due to cell-protein interaction, noting the effect of pH on RBC MF with albumin but not with buffer. Presence of lipids reduced RBC resistance to potentially hemolytic stress with lypemic plasma effecting lower “protection” from induced hemolysis than essentially fatty-acid free plasma. This effect was less dependent on incubation than on fatty-acid presence during stressing. The reduced propensity for hemolysis afforded by plasma proteins also depended markedly on the speed of the bead, potentially reflecting changes from a predominantly Von Karman trail at lower frequencies to an increasingly disorganized turbulent wake at higher frequencies. Show more

Keywords: Red Blood Cells, mechanical fragility, hemolysis, albumin, fibrinogen, gamma-globulin, fatty acid, plasma, blood storage

DOI: 10.3233/CH-152037

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 21-33, 2016

Authors: Majumder, B. | Koganti, S. | Lowdell, M.W. | Rakhit, R.D.

Article Type: Research Article

Abstract: INTRODUCTION: Platelet Monocyte Complexes (PMCs) are commonly expressed in coronary artery disease but their pathologic significance in ST elevation myocardial infarction (STEMI) is unclear. This study evaluates the relationship between locally activated PMCs and intracoronary inflammation in stable and unstable coronary disease. MATERIAL AND METHODS: Micro catheter aspirated blood samples of 15 STEMI and 7 stable angina patients are collected from the coronary artery (CA), aorta (AO) and right atrium (RA). Samples are labelled with monoclonal antibodies and prepared for flow cytometry. CD 14 and CD 61 double positive cells are identified as PMC. P-selectin expression is …identified by additional CD62P positivity and TF expression by additional CD142 positivity. Plasma TNF-alpha and IL-6 are measured using ELISA and CRP is measured in plasma using a high sensitivity automated microparticle enhanced latex turbidimetric immunoassay. RESULTS: No site-specific difference is seen in overall PMC expression in STEMI or stable angina. Surface P-selectin expression in STEMI [median (IQR)] is significantly higher in CA [35.01 (23.15–56.99)] compared with AO [15.99 (10.3–18.85)] or RA [14.02 (10.42–26.08)] (p  = 0.003). Intracoronary PMC correlates significantly with intracoronary TNF-alpha (r  = 0.87, p  = 0.001) and intracoronary IL-6 (r  = 0.76, p  = 0.03). Bound monocytes within P-selectin positive and tissue factor positive complexes correlate positively with intracoronary TNF-alpha (r  = 0.81, p  = 0.008 & r  = 0.80, p  = 0.009 respectively) and IL-6 (r  = 0.54, p  = 0.16 & r  = 0.71, p  = 0.05 respectively). No such correlation is observed in the peripheral circulation of STEMI and stable angina patients. CONCLUSION: Inflammation is not attributable to PMC formation per se. However, increased intracoronary P-selectin expression by activated platelets and tissue factor expression by activated monocytes within the complexes are determinants of local intracoronary inflammatory burden in STEMI. Show more

Keywords: Platelet monocyte complex, platelet and monocyte activation status, intracoronary inflammation, ST elevation myocardial infarction

DOI: 10.3233/CH-162040

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 35-46, 2016

Authors: Mozar, Anaïs | Connes, Philippe | Collins, Bianca | Hardy-Dessources, Marie-Dominique | Romana, Marc | Lemonne, Nathalie | Bloch, Wilhelm | Grau, Marijke

Article Type: Research Article

Abstract: Sickle cell anemia (SCA) is an inherited red blood cells (RBC) disorder characterized by significantly decreased RBC deformability. The present study aimed to assess whether modulation of RBC Nitric Oxide Synthase (RBC-NOS) activation could affect RBC deformability in SCA. Blood of twenty-five SCA patients was treated for 1 hour at 37°C with Phosphate Buffered Saline (PBS) or PBS containing 1% of Dimethylsulfoxyde as control, L-arginine or N(5)-(1-Iminoethyl)-L-ornithine (L-NIO) to directly stimulate or inhibit RBC-NOS, insulin or wortmannin to indirectly stimulate or inhibit RBC-NOS through their effects on the PI3 Kinase/Akt pathway, and sodium nitroprusside (SNP) and 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) as …NO donor and NO scavenger, respectively. RBC deformability was measured by ektacytometry at 3 Pa. RBC deformability significantly increased after insulin treatment and significantly decreased after L-NIO and wortmannin incubation. The other conditions did not affect deformability. Significantly increased nitrotyrosine levels, a marker of enhanced free radical generation, were detected by immunohistochemistry in SNP and insulin treated samples. These data suggest that RBC deformability of SCA can be modulated by RBC-NOS activity but also that oxidative stress may impair effectiveness of RBC-NOS produced NO. Show more

Keywords: Sickle cell disease, red blood cell rheology, nitric oxide

DOI: 10.3233/CH-162042

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 47-53, 2016

Authors: Totsimon, Kinga | Nagy, Alexandra | Sandor, Barbara | Biro, Katalin | Csatho, Arpad | Szapary, Laszlo | Toth, Kalman | Marton, Zsolt | Kenyeres, Peter

Article Type: Research Article

Abstract: BACKGROUND: Carotid artery stenosis (CAS) is not only an important risk factor of cerebrovascular events but it can also indicate generalized atherosclerosis. Hemorheological parameters are altered in CAS and in chronic cerebrovascular disorders as well, but it is controversial if hemorheological parameters could be markers of stenosis or atherosclerosis. METHODS: 107 patients were investigated, 40% of them had stroke or TIA in case history and 48% had CAS. Routine lab parameters were determined and hemorheological variables were measured: hematocrit, plasma viscosity, whole blood viscosity, red blood cell aggregation, and deformability. RESULTS: In the stenotic group …whole blood viscosity and red blood cell aggregation were deteriorated (p  < 0.05). Whole blood and plasma viscosity were higher and red blood cell deformability was lower in the symptomatic group (p  < 0.05). Plasma viscosity and red blood cell deformability were altered in the evolving atherosclerosis group and the CAS groups compared to patients having no signs of stenosis (p  < 0.05), but there was no difference among the CAS groups. CONCLUSION: Although hemorheological parameters are impaired both in CAS and chronic cerebrovascular disorders, the severity of stenosis cannot be detected based on hemorheological parameters. Our investigation suggests that alteration of hemorheological parameters could indicate carotid atherosclerosis. Show more

Keywords: Carotid artery stenosis, hematocrit, viscosity, red blood cell aggregation, red blood cell deformability

DOI: 10.3233/CH-162043

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 55-63, 2016

Authors: Potočnik, N. | Lenasi, H.

Article Type: Research Article

Abstract: This study investigated the responses of skin blood flow (SkBF) in glabrous and nonglabrous skin to graded submaximal dynamic exercise and its recovery. We enrolled eight healthy young men with comparable maximal oxygen uptake (VO2max ). Laser-Doppler flux (LDF) was assessed on the finger pulp (glabrous site) and the volar forearm (nonglabrous site) simultaneously with skin temperature, heart rate and blood pressure; cutaneous vascular conductance (CVC) was calculated. Subjects were monitored before (baseline), during and 25 minutes after incremental cycling. CVC in the pulp decreased with the onset of exercise (0.53±0.09AUmmHg– 1 vs. baseline 1.23±0.25AUmmHg–1 , p  = 0.006), and persisted …low until exercise cessation, whereas CVC in the forearm started to increase at 60% of subjects’ VO2max , attaining its maximum at the highest exercise load (0.44±0.11AUmmHg–1 vs. baseline 0.12±0,03AUmmHg–1 , p  = 0.017). In the recovery, CVC in the pulp attained a higher plateau value compared to baseline (1.51±0.22AUmmHg–1 , p  = 0.021), interrupted by abrupt transient falls of CVC. On the forearm, CVC subsequently returned to its baseline. SkBF of glabrous and nonglabrous sites adjust in an opposite manner to graded exercise load and also differ during recovery. Show more

Keywords: Skin microcirculation, laser Doppler fluxmetry, arterio-venous anastomoses, submaximal graded exercice, recovery to exercise, glabrous skin, nonglabrous skin, cutaneous vascular conductance

DOI: 10.3233/CH-162045

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 65-75, 2016

Authors: Rasche, S. | Trumpp, A. | Waldow, T. | Gaetjen, F. | Plötze, K. | Wedekind, D. | Schmidt, M. | Malberg, H. | Matschke, K. | Zaunseder, S.

Article Type: Research Article

Abstract: BACKGROUND: Camera-based photoplethysmography (cbPPG) is an optical measurement technique that reveals pulsatile blood flow in cutaneous microcirculation from a distance. cbPPG has been shown to reflect pivotal haemodynamic events like cardiac ejection in healthy subjects. In addition, it provides valuable insight into intrinsic microcirculatory regulation as it yields dynamic, two-dimensional perfusion maps. In this study, we evaluate the feasibility of a clinical cbPPG application in critical care patients. METHODS: A mobile camera set-up to record faces of patients at the bed site was constructed. Videos were made during the immediate recovery after cardiac surgery under standard critical …care conditions and were processed offline. Major motion artefacts were detected using an optical flow technique and suitable facial regions were manually annotated. cbPPG signals were highpass filtered and Fourier spectra out of consecutive 10s signal segments calculated for heart rate detection. Signal-to-noise ratios (SNR) of the Fourier spectra were derived as a quality measure. Reference data of vital parameters were synchronously acquired from the bed site monitoring system. RESULTS: Seventy patient videos of an average time of 28.6±2.8 min were analysed. Heart rate (HR) was detected within a ±5 bpm range compared to reference in 83% of total recording time. Low SNR and HR detection failure were mostly, but not exclusively, attributed to non-physiological events like patient motion, interventions or sudden changes of illumination. SNR was reduced by low arterial blood pressure, whereas no impact of other perioperative or disease-related parameters was identified. CONCLUSION: Cardiac ejection is detectable by cbPPG under pathophysiologic conditions of cardiovascular disease and perioperative medicine. cbPPG measurements can be seamlessly integrated into the clinical work flow of critical care patients. Show more

Keywords: Camera-based Photoplethysmography, critical care patients, cutaneous microcirculation

DOI: 10.3233/CH-162048

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 77-90, 2016

Authors: Taeger, Christian D. | Friedrich, Oliver | Drechsler, Caroline | Weigand, Annika | Hobe, Frieder | Geppert, Carol I. | Münch, Frank | Birkholz, Torsten | Buchholz, Rainer | Horch, Raymund E. | Präbst, Konstantin

Article Type: Research Article

Abstract: In the field of free flap transfer in reconstructive surgery, the trans- or replanted tissue always undergoes cell damage during ischemia to a more or less strong extent. In previous studies we already showed that conserving muscle transplants by means of extracorporeal perfusion over a period of 6 hours by using a crystalloid solution for perfusion. However, we observed significant edema formation. In this study we aimed at reducing the edema formation by using an iso-oncotic colloid as perfusion solution. This way we wanted to evaluate a possible new application of hydroxyl-ethyl starch in an extracorporeal setup to exploit potential …benefits of the colloid. Examined parameters include the muscles’ functionality with external field stimulation, histological examination and edema formation. Perfused muscles showed a statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, as perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. Substituting the electrolyte perfusion solution with a colloidal one shows the tendency to reduce the edema formation however without statistical significance. Show more

Keywords: Extracorporeal perfusion, hydroxyethyl starch, free flap, ischemia, transplantation

DOI: 10.3233/CH-162049

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 91-103, 2016

Authors: Mihor, Ana | Gergar, Maša | Gaberšček, Simona | Lenasi, Helena

Article Type: Research Article

Abstract: Hypothyroidism is associated with impaired vascular function; however, little is known about its impact on microcirculation. We aimed to determine skin microvascular reactivity in hypothyroidism focusing on endothelial function and the sympathetic response. We measured skin laser Doppler (LD) flux (LDF) on the volar forearm and the finger pulp using LD flowmetry in hypothyroid patients (N  = 13) and healthy controls (N  = 15). Skin microvascular reactivity was assessed by a three-minute occlusion of the brachial artery, inducing postocclusive reactive hyperaemia (PRH), and by a four-minute local cooling of the hand. An electrocardiogram (ECG), digital artery blood pressure and skin temperature at …the measuring sites were recorded. Baseline LDF, the digital artery blood pressure and the heart rate were comparable between patients and controls. On the other hand, patients exhibited significantly longer PRH duration, significantly higher blood pressure during cooling (unpaired t -test, p <0.05) and lower, albeit not significant, LDF in the ipsilateral finger pulp during cooling compared to controls. Unexpectedly, the results of the present study point to an increased vasodilator capacity of skin microcirculation and an apparent increase in sympathetic reactivity after local cooling in hypothyroid patients. Hypothyroidism induces subtle changes of some haemodynamic parameters in skin microcirculation implying altered endothelial function and altered sympathetic reactivity. Show more

Keywords: Hypothyroidism, skin microvascular reactivity, laser Doppler flowmetry, endothelial function, postocclusive reactive hyperaemia, local cooling, sympathetic response

DOI: 10.3233/CH-162062

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 1, pp. 105-114, 2016