Clinical Hemorheology and Microcirculation - Volume 51, issue 1

Authors: de Almeida, J.P. Lopes | Oliveira, S. | Saldanha, C.

Article Type: Review Article

Abstract: The erythrocytes ability of sensing the local oxygen gradient through the hemoglobin conformation, along with changes in nitric oxide mobilization and vasomotor repercussions at the microcirculation, were reviewed in detail in this article. Different approachs trying to explain the erythrocyte death were additionally documented. Also, the influence of several types of molecules (vasoactive, oxidant/reductor) on the erythrocyte roles as sensor of (i) oxygen tissue needs, (ii) blood viscosity and myogenic environment, (iii) and inflammatory conditions were mentioned in order to highlight its physiologycal function and substitute the erroneous idea of the erythrocyte being simply a hemoglobin sac content.

DOI: 10.3233/CH-2011-1512

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 1-20, 2012

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

Article Type: Research Article

Abstract: Insulin resistance is associated with a mild hyperviscosity syndrome, which is more closely related to insulin resistance than to the clinical scoring of the metabolic syndrome. In studies using the intravenous glucose tolerance test with minimal model analysis we reported that low insulin sensitivity (SI) is associated with increased erythrocyte aggregability (EA). Actually, this issue is confusing because insulin resistance is often associated with compensatory hyperinsulinemia (insulin being a hormone with reported hemorheologic effects) and that a decline in insulin secretion has marked metabolic effects that modify blood rheology. From the intravenous glucose tolerance test (IVGTT) the minimal model allows …the calculation of SI, insulin response, and an overall glucose tolerance parameter termed “disposition index” (DI) that measures whether insulin response is adequate or not for the level of insulin sensitivity. In this study we assessed SI, insulin response, and DI during an IVGTT in 335 subjects of both genders (age 8–77 yr; BMI 14–67 kg/m2 ). SI was only correlated (negatively) with EA (Myrenne M r = −0.285; p = 0.0001; M1 r = −0.240 p = 0.003). Fasting insulin was also correlated (positively) with EA (Myrenne M r = 0.233, 0.00880; M1 r = 0.320 p = 0.0003; SEFAM TA r = −0.342 p = 0.04; SEFAM S60 r = 0.419 p = 0.01) and SEFAM RBC disaggregation thresholds (γS = r = 0.372 p = 0.025; γD = r = 0.504 p = 0.002). Fasting DI (SI × fasting insulin) is negatively correlated to M (r = −0.274; p = 0.002) and M1 (r = −0.225; p = 0.01) but also positively to whole blood viscosity (r = 0.168; p = 0.01) and hematocrit (r = 0.142; p = 0.05). Stimulatory DI (SI × insulin peak) fails to be correlated with any parameter of EA but is negatively correlated to whole blood viscosity (r = −0.150; p = 0.02) and plasma viscosity (r = −0.163; p = 0.01). This study confirms that red cell aggregability is associated with insulin resistance and hyperinsulinemia, but plasma viscosity seems to be more related to overall glucose tolerance than to either SI or insulinemia. Show more

Keywords: Insulin sensitivity, minimal model, hemorheology, erythrocyte deformability, blood viscosity, erythrocyte aggregation

DOI: 10.3233/CH-2011-1425

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 21-27, 2012

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

Article Type: Research Article

Abstract: In studies using the intravenous glucose tolerance test with minimal model analysis we reported that low insulin sensitivity (SI ) is associated with increased erythrocyte aggregability and plasma viscosity, that appeared to be markers of insulin resistance. Recently, development of modelling has made available a new approach of insulin sensitivity from oral glucose tolerance test data (oral minimal model). We aimed at determining in 111 subjects (51 men, 62 women, age 11–77 yr), insulin sensitivity with this approach together with blood viscosity parameters. With this approach the Myrenne indexes of red cell aggregation were negatively correlated to SI (M; …r = −0.456; p = 0.0007; M1; r = −0.397; p = 0.004) while plasma viscosity was not. Correlations with fasting insulin levels (Ib) were weaker (M; r = 0.2711; p = 0.05; M1; r = 0.373; p = 0.007). Accordingly, a stepwise regression analysis selects M as the best correlate of SI and M1 as the best correlate of Ib. With this approach plasma viscosity does not exhibit any clear relationship with SI. This study supports the concept that RBC hyperaggregability is the prominent hemorheologic symptom of insulin resistance. Show more

Keywords: Hemorheology, red cell aggregability, insulin resistance, insulin sensitivity, plasma viscosity, minimal model

DOI: 10.3233/CH-2011-1426

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 29-34, 2012

Authors: Irace, Concetta | Carallo, Claudio | Scavelli, Faustina | Loprete, Antonio | Merante, Valentina | Gnasso, Agostino

Article Type: Research Article

Abstract: Objective: A direct relationship between blood pressure and viscosity has frequently been reported, although clear data are not available. To better understand the relationship between these two variables, we evaluated blood viscosity and blood pressure in a group of healthy subjects without cardiovascular risk factors. Methods: Healthy subjects were selected from participants in a campaign of prevention of cardiovascular disease (n = 103). They underwent blood sampling for measurement of plasma and blood viscosity, haematocrit, blood lipids and glucose. The quantity and distribution of body fat was assessed by body mass index and waist/hip ratio, respectively. Results: Systolic blood pressure …(SBP) correlated significantly with age (r = 0.222) and waist/hip ratio (r = 0.374). Diastolic blood pressure (DBP) correlated significantly with waist/hip ratio (r = 0.216), haematocrit (r = 0.333) and blood viscosity (r = 0.258). Multiple linear regression analyses demonstrated that the only variable significantly associated with SBP was age, while haematocrit was the only variable significantly associated with DBP. Blood viscosity was closely related to waist/hip ratio. Conclusion: These findings show that SBP, in healthy subjects, is not influenced by haematocrit and blood viscosity. In contrast, DBP is related to the values of haematocrit. Among classical cardiovascular risk factors, waist/hip ratio is closely related to blood viscosity. Show more

Keywords: Blood viscosity, blood pressure, CHD risk factors

DOI: 10.3233/CH-2011-1506

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 35-41, 2012

Authors: Nemeth, Norbert | Miko, Iren | Furka, Andrea | Kiss, Ferenc | Furka, Istvan | Koller, Akos | Szilasi, Maria

Article Type: Research Article

Abstract: Acid-base equilibrium and pH of blood have important clinical consequences in numerous diseases and pathophysiological conditions. The micro-rheological parameters of blood, such as red blood cell deformability and red blood cell aggregation are influenced by several metabolic factors, and provide information regarding inflammatory, septic and tissue or organ ischemia-reperfusion processes. Despite the anticipated logical relation of the blood acid-base condition, blood gas parameters and pH to red blood cell deformability and aggregation, controversial data can be found in the literature. Furthermore, related to ischemia-reperfusion hemorheological studies little is known about this issue. In this paper we aimed to thought-provokingly overview …some aspect of acid-base changes, blood pH and hemorheological parameters, discussing certain results from ischemia-reperfusion experimental surgical models (local versus systemic changes), laboratory technical and experimental design protocols related to in vitro and in vivo studies. Show more

Keywords: Acid-base changes, blood pH, micro-rheological parameters, red blood cell aggregation, red blood cell deformability

DOI: 10.3233/CH-2011-1507

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 43-50, 2012

Authors: Vayá, Amparo | Calvo, Javier | Alcalá, Carmen | Micó, Luisa | Todolí, Jose | Ricart, Jose M.

Article Type: Research Article

Abstract: Systemic lupus erythematosus (SLE) is characterised by increased venous and arterial thrombotic risk. Nevertheless, how hemorheological alterations contribute to thrombotic risk remains a question of debate. We aimed to determine the rheological profile in 105 patients with SLE (24 with a thrombotic event) and 105 healthy controls. We determined blood viscosity and erythrocyte aggregation along with plasma lipids and fibrinogen. Although SLE patients showed lower blood viscosity at 230 s−1 at a native hematocrit when compared with controls (p < 0.001), differences disappeared after adjusting the hematocrit to 45% (p = 0.095). When comparing SLE patients with and without …thrombotic events, no differences in any rheological parameter were found (p > 0.05), except in fibrinogen which was higher in patients with thrombosis (p = 0.013). No differences in the rheological parameters were observed when venous and arterial thrombotic events were compared, although a tendency for higher fibrinogen was observed in patients with venous thrombosis (p = 0.053). Only hematocrit, fibrinogen and triglycerides were independent predictors of native blood viscosity in the multivariate regression analysis, even after adjusting for continuous variables and for tobacco and hypertension: beta coefficient: 0.727 p < 0.001; beta coefficient: 0.152 p = 0.003 and beta coefficient: 0.133 p = 0.015, respectively. The logistic regression analysis revealed that neither increased native blood viscosity (BVn > 4.33) nor increased erythrocyte aggregation (EA1 > 7.85) increased thrombotic risk: OR 0.636, CI 0.313–3.12, p = 0.578 and OR 2.01, CI 0.77–5.20, p = 0.152, respectively. However, hyperfibrinogenemia (Fbg > 342 mg/dL) increased thrombotic risk by around three times: OR 3.44 CI 1.32–8.96, p = 0.011. Our results suggest that the role of blood viscosity and erythrocyte aggregation in thrombotic risk in SLE patients fails to demonstrate any association. Show more

Keywords: Systemic lupus erythematosus, thrombosis, hemorheology

DOI: 10.3233/CH-2011-1508

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 51-58, 2012

Authors: Li, Guolin | Hu, Hui | Shi, Wang | Li, Ye | Liu, Li | Chen, Yaqin | Hu, Xiaofei | Wang, Jun | Gao, Jun | Yin, Dazhong

Article Type: Research Article

Abstract: Background and aim: Hematocrit is an important hemorheological parameter. Both hematocrit and nonalcoholic fatty liver disease (NAFLD) are strongly correlated with cardiovascular disease. However, there is no study to explore the direct relationship of hematocrit with NAFLD. Methods: Hematocrit levels were analyzed from 1,821 Chinese Han adults, and questionnaire and physical examination were administered to know and suspect the relationship with NAFLD. Results: NAFLD morbidity was positively correlated with hematocrit levels in both male and female. Multivariate-adjusted odds ratio illustrated that, compared with the lowest quartile of hematocrit, the highest quartile subjects had a 185% and 386% increased risk for …developing NAFLD in male and female, respectively. Further receiver operating characteristic analysis showed that the optimal cutoff value of hematocrit for detecting NAFLD was 42.75 in male and 37.55 in female. Unhealthy lifestyles had similar effects on NAFLD and hematocrit. Conclusions: The prevalence of NAFLD is positively associated with hematocrit levels. Though the cause-effect relationship between NAFLD and hematocrit still needs further investigation to clarify, the elevated hematocrit in NAFLD patients may be of significance to link NAFLD and cardiovascular disease. Show more

Keywords: Nonalcoholic fatty liver disease (NAFLD), hematocrit, cardiovascular disease

DOI: 10.3233/CH-2011-1509

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 59-68, 2012

Authors: Klonizakis, Markos

Article Type: Research Article

Abstract: This study investigated changes incurred in cutaneous skin blood flux (SKBF) in the superficial veins of the lower limb by upper limb exercise training in the form of arm-cranking in 14 healthy participants over the age of 50 years. Changes in cutaneous microvascular function of the lower leg were assessed using laser Doppler Flowmetry (LDF) during a 30-minute exercise session undertaken over 4-exercise periods. Both SKBF and Time to reach Peak Perfusion (Tmax) were improved significantly during the 2nd (e.g. 121 (± 107.2) vs 280 (± 269.1) and 171 (± 34.4) vs. 247 (± 38.3) respectively) when compared to the …first exercise period, while values approaching initial levels in the following stages. The results indicate that the thermoregulatory and vasodilation mechanisms observed during exercise in middle-aged and older healthy people are different to the one appearing in younger age groups, suggesting a more extensive effect of the age-related structural changes than it was previously thought. Show more

Keywords: Skin blood flow, arm-cranking exercise, cutaneous microcirculation, perfusion, skin temperature

DOI: 10.3233/CH-2011-1510

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 69-75, 2012

Authors: Cheung, A.T.W. | Hu, B.S. | Wong, S.A. | Chow, J. | Chan, M.S. | To, W.J. | Li, J. | Ramanujam, S. | Chen, P.C.Y.

Article Type: Research Article

Abstract: Soft contact lenses are commonly used to improve vision acuity or in cosmetic enhancement. We hypothesize that contact lens use can cause inadvertent damage to either the conjunctival microcirculation via direct vasoocclusion when the lens physically interacts with or damages the underlying vessels, or to the bulbar conjunctiva itself when the lens rests unevenly on the surface of the bulbar conjunctiva. Computer-assisted intravital microscopy was utilized to document (via video recording) and objectively quantify (via image analysis) real-time microvascular abnormalities resulting from changes and vessel remodeling in the conjunctival microcirculation in long-term (>2 yrs) contact lens users (n = 102), …with non-users serving as control subjects (n = 29). A severity index (SI) – computed as the arithmetic sum of the abnormalities found in the conjunctival microcirculation in each contact lens user – was established for objective comparison with control subjects and critical interpretation. Contact lens user SI was significantly higher than control SI (user = 6.21 ± 1.26; control = 2.31 ± 1.49; p < 0.05), indicative of severe vasculopathy arising from contact lens use. The users also had significantly wider conjunctival vessel diameter (user = 71.25 ± 12.09 μm; control = 52.20 ± 5.10 μm; p < 0.05). Additional abnormalities, including damaged vessels, hemosiderin deposits (from damaged vessels or injury to the surface of the bulbar conjunctiva), vessel sludging, intermittent blood flow, and vessel tortuosity were commonly found in or adjacent to locations where the contact lens physically rested on the underlying conjunctival vessels. These results strongly suggest that microvascular abnormalities and remodeling changes occurred as a result of the inadvertent physical interaction of the lenses with either the underlying conjunctival vessels or the surface of the bulbar conjunctiva in contact lens users. Show more

Keywords: Contact lens, conjunctival microcirculation, bulbar conjunctiva, intravital microscopy

DOI: 10.3233/CH-2011-1513

Citation: Clinical Hemorheology and Microcirculation, vol. 51, no. 1, pp. 77-86, 2012