Clinical Hemorheology and Microcirculation - Volume 54, issue 1

Authors: Fasano, Antonio | Pavlova, Jevgenija | Sequeira, Adélia

Article Type: Research Article

Abstract: Modeling blood coagulation has taken various directions in recent years, depending on the aspects that authors wish to emphasize. In this paper we want to address an issue that has been systematically ignored in the relevant literature, namely the effect of blood slip at the vessels wall. The presence of a slip results in an increased supply of activated platelets to the clotting site. We calculate such a contribution showing that, in extreme cases, it can be even dominant. Indeed, raising the concentration of activated platelets induces an acceleration of thrombin production and eventually of the whole clot progression. The …model explains the difference between arterial and venous thrombi. We confine to the coagulation stage known as “propagation phase” in the context of the so called cell based model. The paper is preparatory for a deeper analysis in which the clotting process is coupled to blood rheology and that will be carried out in the future by the same authors. At the present stage, the extremely complex biochemistry has been simplified adopting a leaner, though virtual, system of diffusion-convection-reaction equations, in the optics of providing “modular” models, that can be reduced or enlarged so to meet specific modeling requirements. Show more

Keywords: Blood rheology, blood clot, platelets, chemical cascade, slip boundary conditions

DOI: 10.3233/CH-2012-1558

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 1-14, 2013

Authors: Ucak, Sema | Basat, Okcan | Çetinkaya, Emel

Article Type: Research Article

Abstract: BACKGROUND AND AIM: Plasma viscosity, which is affected by plasma lipid and protein composition, is a hemorheological parameter accepted as an early cardiovascular risk factor. In this study we aimed to investigate the alterations in plasma viscosity in patients with metabolic syndrome since both are early predictors of CVD. MATERIAL AND METHODS: A total number of 70 patients aged between 25–55 years with the diagnosis of metabolic syndrome according to IDF 2005 criteria and 32 age and sex matched healthy subjects were allocated consecutively in the study. Body mass index (BMI), arterial blood pressure, blood glucose, total cholesterol, HDL and …triglyceride levels were measured and plasma viscosity was measured. The results of patients with MS and healthy subjects were compared. Correlation between components of the Metabolic Syndrome and plasma viscosity was assessed. RESULTS: BMI, systolic and diastolic blood pressure, waist circumference, serum lipid and glucose levels and plasma viscosity levels were higher in patient group (p < 0.001). A positive correlation was determined between plasma viscosity and waist circumference, hypertension and serum lipid levels (r = 0.401, p = 0.003). CONCLUSION: Plasma viscosity is increased in patients with metabolic syndrome and it is associated with waist circumference, hypertension and plasma lipid levels. Show more

Keywords: Plasma viscosity, metabolic syndrome

DOI: 10.3233/CH-2012-1559

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 15-22, 2013

Authors: Olatunji, Lawrence Aderemi | Oyeyipo, Ibukun Peter | Usman, Taofeek Oluwamayowa

Article Type: Research Article

Abstract: Oral contraceptive (OC) use and increased fructose feeding have been associated with altered cardiometabolic effects. The effect of increased dietary fructose during OC use on cardiometabolic parameters is unknown. We investigated the effects of a high-fructose diet on body weight gain, fasting blood glucose, glucose tolerance, plasma lipid and hemorheological parameters in female rats treated with a combination of OC steroids (norgestrel/ethinyl estradiol; NEE). Rats were given (p.o.) vehicle, high-dose NEE (10.0 μg norgestrel/1.0 μg ethinyl estradiol) or low-dose NEE (1.0 μg norgestrel/0.1 μg ethinyl estradiol) with or without high dietary fructose daily for 6 weeks. Results demonstrated that high-dose …NEE but not low-dose NEE treatment led to significant increases in hematocrit, blood viscosity, and decreases in body weight gain, glucose tolerance, and plasma HDL-cholesterol level. Both NEE treatments resulted in significant increases in plasma viscosity and triglyceride. Increased dietary fructose without NEE treatment produced significant increases in fasting blood glucose, hematocrit, blood and plasma viscosities, while increased dietary fructose significantly potentiated the effects on blood and plasma viscosities observed during NEE treatment. Conversely, the effects of NEE treatment on body weight gain, glucose tolerance, plasma triglyceride and HDL-cholesterol were significantly attenuated. In conclusion, the results indicate that increase in dietary fructose may worsen abnormal blood rheology. The results also demonstrate that increased dietary fructose may not impact negatively on glucose and lipid metabolisms during OC use. The findings imply that fructose-enriched diet might be an important consideration during OC use regarding blood rheological properties. Show more

Keywords: Dietary fructose, glucose tolerance, hemorheology, lipoprotein, oral contraceptive, triglyceride

DOI: 10.3233/CH-2012-1561

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 23-31, 2013

Authors: Ruiz, Carolina | Hernandez, Glenn | Andresen, Max | Ince, Can | Bruhn, Alejandro

Article Type: Research Article

Abstract: A 60-year women was admitted to ICU because seizures, poor peripheral perfusion and acute renal failure. In laboratory tests an hyperproteinemia was detected, and therefore an electrophoresis and a bone marrow biopsy were performed, confirming a Waldenström Macroglobulinemia with severe hyperviscosity. Sublingual microcirculation was assessed with videomicroscopy, finding sluggish and intermittent microvascular flow, despite normal lactate and mixed venous O2 saturation. Promptly plasmapheresis was started, with viscosity decrease in parallel with improvement in microvascular flow and clinical status. Three days after the first plasmapheresis the patient was discharged from ICU. This case shows the critical role of viscosity on microcirculatory …flow. Show more

Keywords: Microcirculation, hyperviscosity, videomicroscopy

DOI: 10.3233/CH-2012-1562

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 33-38, 2013

Authors: Lo Presti, Rosalia | Canino, Baldassare | Montana, Maria | Caimi, Gregorio

Article Type: Research Article

Abstract: Our aim was to investigate the effects of an exercise test on some indices of oxidative status and endothelial function, in trained and untrained subjects. We examined lipid peroxidation, nitric oxide metabolites (NOx) and their ratio before and after a cardiopulmonary test, using a cycloergometer. We enrolled 60 male subjects who practiced sport unprofessionally, subdivided in two groups (A and B) according to the values of VO2 max. Group A included sportsmen with poor or fair aerobic fitness (VO2 max <39 ml/Kg/min), group B sportsmen with average to excellent aerobic fitness (VO2 max >39 ml/Kg/min). The control group included 19 …male sedentary subjects. Lipid peroxidation was evaluated by detection of the thiobarbituric acid-reactive substances (TBARS); the NOx were evaluated employing the Griess reagent. At rest, in comparison with sedentary controls, an increase in TBARS, NOx and TBARS/NOx ratio was found in all sportsmen and partially in the two groups. After the cardiopulmonary test, the increase of TBARS and TBARS/NOx ratio was significantly more evident in sedentary controls than in sportsmen. No variation was observed for NOx in any group. These data suggest that sportsmen are protected against the acute oxidative stress induced by an exercise test, and that protection is not strictly dependent on the aerobic fitness. Show more

Keywords: Lipid peroxidation, nitric oxide metabolism, sportsmen

DOI: 10.3233/CH-2012-1563

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 39-49, 2013

Authors: Ricart, José Maria | España, Francisco | Navarro, Silvia | Todolí, José | Miguel De la Fuente, José | Vayá, Amparo

Article Type: Research Article

Abstract: Behçet's disease (BD) is a chronic inflammatory disorder in which thrombosis and posterior ocular involvement occur in about 30% of patients, whose ethiology is unknown. It has not been established whether mean platelet volume (MPV), a marker of platelet activation, is involved in the pathogenesis of thrombotic events and posterior uveitis in these patients. We aimed to analyze whether there are differences in MPV in BD patients when compared with controls and its relation with the presence of thrombosis and posterior uveitis. We determined MPV and platelet count, along with C-reactive protein (CRP) and cardiovascular risk factors (because of their …influence on MPV) in 89 BD patients (of which 24 had thrombosis and 23 had posterior uveitis) and 89 sex- and age-matched healthy controls. BD patients showed statistically higher MPV than controls: 10.98 ± 1.19 fL vs. 10.60 ± 1.21 fL (P = 0.044) and higher CRP: 5.9 ± 8.9 mg/L vs. 1.4 ± 1.7 mg/L (P = 0.001). The percentage of hyperlipemia and diabetes was higher in cases than in controls (P = 0.032, P = 0.013, respectively). No differences in MPV were observed when comparing: patients with and without thrombosis: 11.8 ± 1.27 fL vs. 10.94 ± 1.28 fL (P = 0.654); with and without posterior uveitis: 10.76 ± 1.18 fL vs. 11.03 ± 1.30 fL P = 0.398; with CRP and cardiovascular risk factors (P > 0.05). MPV correlated negatively with platelet count (r = −308, P < 0.01), but not with CRP (r = −0.22, P = 0.772). MPV seems to relate to neither thrombosis nor posterior uveitis in BD patients. Show more

Keywords: Behçet's disease, mean platelet volume, thrombosis, posterior uveitis

DOI: 10.3233/CH-2012-1564

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 51-57, 2013

Authors: Kaiser, Ralf | Grotemeyer, Katharina | Kälsch, Thorsten | Gräber, Stefan | Wilkens, Heinrike | Elmas, Elif

Article Type: Research Article

Abstract: BACKGROUND: TSP-1 is a vasoconstrictive protein, which is released from both endothelium and cardiomyocytes during ischemia and promotes platelet aggregation and adhesion to subendothelial layers in atherosclerotic lesions. During myocardial ischemia and reperfusion, TSP-1 disturbs local microcirculation by disrupting both NO-signaling as well as VEGF-pathways by activation of CD47 and CD36. Furthermore, activation of TGF-ß might induce excessive fibrosis after infarction. It was assumed that TSP-1 is washed out after successful coronary reperfusion. In this study, we examined circulating TSP-1 post emergency PCI as a risk factor for major adverse cardiac events after STEMI with and without ventricular fibrillation. METHODS: …TSP-1 levels in platelet poor plasma were measured in 54 patients after ST-elevation myocardial infarction. Major adverse cardiac events were monitored for 426 days. RESULTS: Patients with decreased TSP levels after coronary stenting showed a significantly higher risk for MACE than patient with higher TSP levels (TSP-1[d0]: n = 46, no MACE = 16.38 ± 1.98 ug/mL vs. MACE 7.11 ± 1.54 ug/mL; p = 0.003). Kaplan-Meyer-analysis for MACE showed a better outcome above 10 ug/mL (p = 0.02). For MACE later than 3 months post-STEMI, the corresponding Kaplan-Meier-analysis yielded a p-value of 0.01. The number needed to diagnose for late MACE was 2.158. CONCLUSION: Low plasma levels of TSP1 after PCI are associated with MACE. Due to its procoagulant effects and dysregulation of microvascular tone, adequately powered prospective studies are warranted to test the impact of TSP-1 on cardiac microcirculation, endothelial function and remodeling. TSP-1 might serve as a new diagnostic and therapeutic approach in cardiovascular disease. Show more

Keywords: Thrombospondin-1, ST-elevation myocardial infarction, major adverse cardiac events, percutaneous coronary intervention

DOI: 10.3233/CH-2012-1565

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 59-73, 2013

Authors: Quitter, Felix | Figulla, Hans R. | Ferrari, Markus | Pernow, John | Jung, Christian

Article Type: Research Article

Abstract: OBJECTIVES: Heart failure (HF) is defined as the incapability of the heart to serve the tissues adequately with blood. This includes changes in microvascular perfusion. A mechanism aggravating perfusion disturbances in HF is endothelial dysfunction by reduced bioavailability of nitric oxide (NO). A mechanism possibly contributing to low NO bioavailability is the upregulation of arginase. Therefore, we investigated circulating arginase levels in patients with HF and its consequences for microvascular perfusion. METHODS: A first group consisted of eighty patients with chronic HF. Patients were characterized by echocardiography and laboratory values. Arginase 1 levels were determined using a commercially available ELISA. …A second experimental group included eight patients with severe heart failure. Using sidestream darkfield intravital microscopy sublingual microcirculation was quantified before and after the topical incubation of nor-NOHA as arginase inhibitor and L-NMMA as NO synthase inhibitor. RESULTS: Circulating arginase-1 levels were significantly higher in patients with heart failure compared to controls (p < 0.001). Patients with severe heart failure (NYHA III/IV) had significantly higher arginase-1 levels compared to patients with mild heart failure (p < 0.01, NYHA I/II). Sublingual perfused capillary density increased significantly (p < 0.01) following incubation with nor-NOHA. However, this effect was abolished when nor-NOHA was co-incubated with L-NMMA. Conclusions: In conclusion, circulating arginase 1 levels are elevated in patients with HF. A topical inhibition of arginase in these patients leads to improved microcirculation by a NO dependent mechanism. Inhibition of arginase is a possible therapeutic target to rescue microcirculation in patients with HF. Show more

Keywords: Microcirculation, arginase, heart failure, SDF, intravital microscopy

DOI: 10.3233/CH-2012-1617

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 75-85, 2013

Authors: Salgado, Diamantino Ribeiro | Favory, Raphaël | Rocco, José Rodolfo | Silva, Eliézer | Ortiz, Julian Arias | Donadello, Katia | Creteur, Jacques | Vincent, Jean-Louis | De Backer, Daniel

Article Type: Research Article

Abstract: CONTEXT: The renin-angiotensin system is activated in patients with acute severe heart failure, and increased levels of angiotensin II could contribute to microcirculatory defects in these patients. OBJECTIVE: To evaluate the microcirculatory effects of angiotensin II antagonists in critically ill patients with severe heart failure. METHODS: After Ethics Committee approval and signed consent, we conducted a prospective observational study using sidestream darkfield (SDF) imaging to evaluate changes in the sublingual microcirculation of 25 adult patients with severe heart failure (ejection fraction < 40% or cardiac index < 2.5 L/min.m2 ) who received angiotensin inhibitors during their ICU stay. SDF images …and global hemodynamic data were obtained immediately before and 4 h, 24 h, and 48 h after the first administration of the drug. RESULTS: Already 4 h after administration, there was a significant improvement in the proportion of perfused small (<20 μm) vessels (PPV) (from 78 [72–84] to 89 [82–94]%, P < 0.05) and the microvascular flow index (MFI) (from 2.25 [1.95–2.50] to 2.80 [2.39–2.95] points, P < 0.05), which persisted over subsequent hours. Large vessel perfusion remained constant. There was no correlation between changes in the PPV and changes in the mean arterial pressure (R2 0.02, P = 0.50), cardiac output (R2 0.004, P = 0.85), or central or mixed venous oxygen saturation (R2 0.03, P = 0.53). CONCLUSIONS: In patients with severe heart failure, introduction of angiotensin antagonist therapy was associated with an early improvement in the microcirculation that persisted over subsequent hours. The microcirculatory effects were independent of global hemodynamic variables. The improvement in microcirculatory perfusion observed with angiotensin inhibitors in patients with severe heart failure may partially explain the beneficial clinical effects of this intervention in such patients. Show more

Keywords: Heart failure, angiotensin II, rennin, angiotensin-converting enzyme antagonists, critically ill

DOI: 10.3233/CH-2012-1569

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 87-98, 2013

Authors: Baskurt, Oguz K. | Meiselman, Herbert J.

Article Type: Research Article

Abstract: Laser-diffraction ektacytometry is a generally accepted technique for measuring RBC deformability induced by fluid shear stress (SS) and yields paired elongation index-SS data at several levels of stress. Unfortunately, comparison of results is hindered by the lack of simple indices that accurately characterize these data. Several mathematical models have been proposed, including those developed for analysis of enzyme kinetics (Lineweaver-Burk, Eadie-Hofstee) and curve fitting (Streekstra-Bronkhorst). All of these analytical approaches provide a value for cell deformation at infinite stress (EImax ) and the shear stress required to achieve one-half of this deformation (SS1/2 ); the use of non-linear regression is …essential when calculating these parameters. While the current models provide equivalent results for normal RBC if used with non-linear regression, EImax and SS1/2 are not always concordant for cells with abnormal mechanical behavior. This technical note examines such differences for three conditions: glutaraldehyde treatment, mechanical stress and non-isotonic media. It was found that none of the models yield completely satisfactory values for EImax and SS1/2 , especially if there are large changes of EImax . However, the ratio of SS1/2 to EImax (SS1/2 /EImax ) is much less affected by these problems, has similar power (i.e., standardized difference) as SS1/2 and EImax and is more robust in reflecting alterations of deformability. We thus conclude that the SS1/2 /EImax ratio can be used when reporting and comparing various populations of RBC or cells obtained from subjects having different clinical states. Show more

Keywords: Red blood cell deformability, hemorheology, data reduction, ektacytometry

DOI: 10.3233/CH-2012-1616

Citation: Clinical Hemorheology and Microcirculation, vol. 54, no. 1, pp. 99-107, 2013