Clinical Hemorheology and Microcirculation - Volume 30, issue 3-4

Authors: Binzen, E. | Lendlein, A. | Kelch, S. | Rickert, D. | Franke, R.P.

Article Type: Research Article

Abstract: Biomaterial research is expected to forward new materials to be used as, e.g., implant materials or as scaffolds for tissue engineering. It is central for such a scaffold material to create the track on which those cells can inhabitate the scaffold needed to rebuild functional tissue substitutes. For the biointegration of the implant with the native cellular tissue this must be able to grow on the material surface. For the elimination of the degradation products and the adeqaute transport of nutrients/gases within the newly formed tissue the angiogenesis of new blood vessels is thought to play an important role. …In the present study, a new biomaterial, a non‐porous polymeric AB‐network based on oligo (ε‐hydroxycaproat) and oligobutylacrylat, was implanted in animals. Male NMRI mice were implanted subcutaneously for one week to nine weeks. Immediately after the explantation, the probes were examined histologically. Already one week after implantation, there was a strong tissue‐integration of the polymer. Importantly, blood vessels appeared at the polymer surface. At nine weeks after implantation the tissue integration was stronger than after one week and blood vessels were still observed in the periimplant tissue. The mechanism of the early integration of the polymer is not clear. The relationship between the new periimplant vessels and the integration of the polymer has to be studied. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 283-288, 2004

Authors: Turchetti, V. | Boschi, L. | Donati, G. | Borgogni, G. | Coppola, D. | Dragoni, S. | Bellini, M.A. | Sicuro, S. | Mastronuzzi, V.M.A. | Forconi, S.

Article Type: Research Article

Abstract: Hemorheological alterations which can be found in ischaemic vascular diseases are well known and widely studied; less clear is the relationship between these alterations and endothelial function. Our studies showed that modifications in endothelial function caused by physical stress are associated with a worsening in hemorheological parameters mainly in patients affected by ischaemic vascular diseases: major vascular alterations have been found in patients with very high levels of plasma markers endothelial dysfunction. The control of the basal tone of the vessels is given by the complex interaction between vasoconstrictor and vasodilator endothelial factors and when this equilibrium is broken we …have the endothelial dysfunction. From a methodological point of view we can find an endothelial dysfunction index determining the various substances produced by the endothelium, but it is very difficult to have a value which clearly identifies the real state of the endothelial alteration. The function of the NO, which is one of the more powerful endogenous vasodilators and whose synthesis is catalysed by nitric oxide synthase (NOS), can be determined by the ratio between blood concentrations of citrulline and arginine (the co‐product and the precursor of the way of NO synthesis), which represents the level of activity of the enzyme. A very affordable index of the endothelial dysfunction is the asymmetric dimethylarginine (ADMA), a powerful endogenous inhibitor of NOS; in fact several studies demonstrated a strong relationship between ischaemic vascular diseases and high levels of plasma ADMA. Evaluation of these parameters is measured by means of high performance liquid chromatography (HPLC): this technique provides very affordable results and allows to obtain evaluations of substances in very small concentrations, like ADMA. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 289-295, 2004

Authors: Le Dévéhat, C. | Vimeux, M. | Khodabandehlou, T.

Article Type: Research Article

Abstract: Blood rheology is now receiving increasing attention as an important potential contributory factor to diabetic angiopathy. This study was designed to provide evidence for and against early hemorheological abnormalities in diabetes mellitus (DM). For this purpose, blood viscosity, RBC aggregation, hematocrit, and plasma protein's levels of both fibrinogen and albumin were measured in 86 uncomplicated patients with DM (45 type 1 and 41 type 2). Patients with HbA1c < 7.5% were considered as having good glycemic control (GGC), while those with HbA1c > 8.5% as having poor glycemic control (PGC). Patients with type 1 DM showed normal blood viscosity at …both shear rates high and low, while native hematocrit, fibrinogen, and RBC aggregation were significantly elevated and albumin significantly reduced when compared with healthy volunteers. Patients with type 2 DM showed more marked impairments associated with an increased low shear rate blood viscosity, when compared with patients with type 1 DM. Comparison between two subgroups of patients, both of which with type 1 DM and of similar disease duration of <5 yrs, with GGC or PGC showed that impaired blood rheology does depend on the quality of glycemic control. Differences were attenuated after a disease duration of >15 yrs. These findings suggest that early hemorheological impairments in patients with type 1 DM are dependent upon the glycemic control. In contrast, hemorheological impairments appear to be inevitable after a mean disease duration of 15 yrs even if there is a GGC. Aggravation of hemorheological abnormalities in patients with type 2 DM might depend upon the hemorheological effects of other metabolic abnormalities related to insulin resistance rather than the quality of glycemic control. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 297-300, 2004

Authors: Cicha, I. | Suzuki, Y. | Tateishi, N. | Maeda, N.

Article Type: Research Article

Abstract: Atherogenic diets rich in saturated fat and cholesterol influence the blood viscosity and red blood cell (RBC) aggregability, the parameters associated with increased risk of circulatory disorders. However, little is known about the effect of triglycerides, which are the major dietary lipid form in humans, on blood rheology. Therefore, we studied the effects of postprandial plasma triglyceride levels on human RBC indices, hematological parameters, RBCs aggregation velocity and whole blood viscosity. For this purpose, whole blood was collected 2 hours after high‐fat or low‐fat meal. Proteins, triglycerides and cholesterol levels of plasma were analysed, and RBCs rouleaux formation rate was …measured in 70% autologous plasma using a low‐shear rheoscope. There were no significant differences in hematological parameters, RBC indices, whole blood viscosity, plasma protein and cholesterol content between high‐fat and low‐fat blood samples. However, a significant increase in rouleaux formation rate was observed in samples with high postprandial triglyceride levels, when compared with low‐triglyceride samples. Plasma triglyceride levels correlated significantly with rouleaux formation rate. In conclusion, these results suggest that diet‐dependent alterations of plasma triglyceride levels as well as possible changes in the cell membrane lipid composition lead to RBC hyperaggregability. Show more

Keywords: Triglycerides, blood rheology, RBC aggregation

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 301-305, 2004

Authors: Khodabandehlou, T. | Boisseau, M.R. | Le Dévéhat, C.

Article Type: Research Article

Abstract: During chronic venous insufficiency (CVI), several microvascular functional abnormalities, due to venous hypertension, develop. To look for blood rheological consequences of venous hypertension “VH”, whole blood viscosity and its main determinants were measured in 11 normal controls and 36 patients with CVI exposed to a short‐term experimental VH. Patients were subdivided into 2 groups according to the severity of their disease. Blood was taken from a foot vein before and after VH, which was induced by appling a pneumatic tourniquet to 100 mmHg for 15 minutes. Whole blood viscosity at low and high shear rates, red blood cell (RBC) aggregation, …RBC rigidity, plasma viscosity and proteins as well as red and white blood cell (WBC) counts were recorded. Patients at baseline, i.e., before application of the tourniquet, showed several hemorheological abnormalities such as an increased RBC aggregation, increased low shear rate viscosity, and a significant elevation in plasma fibrinogen level. Patients with more severe CVI had more marked hemorheological changes. The short term VH in patients led to further aggravation of these changes. There were also at baseline lower values, however not significantly, of hematocrit and RBC count, suggesting that hemoconcentration is not a feature of CVI. These same parameters were slightly, however not significantly, increased after VH, indicating a fluid escape into the extravascular space. A significant fall in WBC count was also observed after VH, in keeping with the white cell trapping hypothesis. In conclusion, even a short‐term VH is able to induce several hemorheological impairments, which are probably involved in the failure of the microcirculation and hence the initiation of tissue damage in patients with CVI. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 307-312, 2004

Authors: Di Massimo, C. | Scarpelli, P. | Tozzi‐Ciancarelli, M.G.

Article Type: Research Article

Abstract: In this study, we have attempted to verify whether a single bout of strenuous exercise performed by sedentary healthy individuals may interfere with the mechanisms controlling platelet sensitivity through exercise‐related modifications of plasma oxidant/antioxidant equilibrium. Strenuous exercise resulted in an increased ADP‐ and collagen‐evoked platelet aggregation associated with modified membrane fluidity and ion homeostasis. We also observed an enhanced plasma accumulation of secondary products of lipid peroxidation together with an increased susceptibility of low density lipoprotein (LDL) to in vitro oxidation and a decreased total plasma antioxidant potential. Notably, an acute elevation of nitrite/nitrate (NOx ) amount was detected in …plasma, whilst a decreased NOx content was measured in platelets. Findings of the current study suggest that oxidative stress induced by acute strenuous exertion may interfere with platelet responsiveness by promoting ox‐LDL‐mediated platelet activation and by decreasing platelet‐derived nitric oxide bioactivity. Show more

Keywords: Exercise, oxidative stress, ox‐LDL, nitric oxide, human blood platelets

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 313-316, 2004

Authors: Aydogan, Sami | Yerer, M. Betul | Yapislar, Hande

Article Type: Research Article

Abstract: Erythrocyte deformability is one of the most important charactheristics of erythrocytes for an effective microcirculatory function and is affected from a number of factors, including the oxidative‐damage‐induced by nitric oxide (NO). This study was performed to investigate the effects of in vitro melatonin incubation on the antioxidant status and deformability of erythrocytes in sodium nitroprusside (SNP), a nitric oxide donor, induced oxidative stress. 40 blood samples taken from the adult healthy people were divided into 4 groups randomly and incubated with saline, SNP (1 mM), melatonin (MEL, 1 mM), MEL + SNP and SNP + L‐NAME (5 mM) respectively. Relative …filtration rate (RFR), relative filtration time (RFT) and relative resistance (Rrel) were determined as the indexes of erythrocyte filterability. In addition, malondialdehyde (MDA, as an index of lipid peroxidation) and the antioxidant activities of glutathione peroxidase (GSH‐Px), superoxide dismutase (SOD) and catalase (CAT) were also determined in the red blood cells of all groups revealing the oxidant–antioxidant activity. RFT and the Rrel of the erythrocytes incubated with SNP increased significantly (p<0.05) whereas the RFR of the erythrocytes decreased (p<0.05) in comparison to all groups. This reduction in RFR was prevented with both L‐NAME or MEL incubation. Furthermore, MEL was found to be significantly efficient in preventing the erythrocytes from lipid peroxidation in these groups. In addition, GSH‐Px and SOD activities were elevated with SNP incubation reflecting the oxidative stress in erythrocytes, whereas the CAT activity remained unchanged. Melatonin has no significant effect on the GSH‐Px and CAT activity but, it caused a significant decrease in SOD activity (p<0.05). These results reveal that, melatonin can protect the erythrocytes from impaired deformability in SNP‐induced oxidative stress due to antioxidant effects as revealed by lipid peroxidation and antioxidant enzyme activities. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 317-322, 2004

Authors: Yerer, M. Betul | Aydogan, Sami

Article Type: Research Article

Abstract: Reactive oxygen species avidly reacts with nitric oxide (NO) producing cytotoxic reactive nitrogen species capable of nitrating proteins and damaging other molecules which leads to the reduction of erythrocyte deformability. The aim of this investigation was to assess the importance of α‐tocopherol (Vit‐E) in the total antioxidant status of the erythrocytes in sodium nitroprusside (SNP), a nitric oxide donor, induced oxidative stress and its relation to erythrocyte deformability. Male Swiss Albino rats were used in 4 groups, comprising of 10 animals in each group. The first group was the control, and the other groups were administered SNP (10 mg/kg, i.p.), …Vit‐E (10 mg/kg, i.p.) + SNP, and SNP + L‐NAME (10 mg/kg, i.p.), respectively. Relative filtration rate (RFR), relative filtration time (RFT) and relative resistance (Rrel) were determined as the indexes of erythrocyte deformability. In addition, malondialdehyde (MDA, as an index of lipid peroxidation) and nitric oxide levels and the antioxidant activities of glutathione peroxidase (GSH‐Px), superoxide dismutase (SOD) and catalase (CAT) were also determined in the red blood cells of all groups revealing the oxidant‐antioxidant activity. RFT and the Rrel of the erythrocytes of the SNP‐treated rats increased significantly (p<0.05) whereas the RFR of the erythrocytes decreased (p<0.05) in comparison to all groups reflecting the impaired deformability. This reduction in RFR was prevented with both L‐NAME or Vit‐E incubation. Vit‐E has also reduced the Rrel of the erythrocyte which reveals that it has improved the erythrocyte deformability. Lipid peroxidation was suppressed by Vit‐E and L‐NAME significantly, where the red blood cell deformability was improved. Furthermore, SOD and CAT activities were significantly stimulated with SNP treatment (p<0.05), where as GSH‐Px remained unchanged. In the contrary, GSH‐Px activity was triggered significantly by Vit‐E administration, whereas the SOD and CAT activities were reduced (p<0.05). As a result, these data reveal that Vit‐E improves the erythrocyte deformability in SNP‐induced oxidative stress by its antioxidant effects on the lipid peroxidation and antioxidant enzyme activities. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 323-329, 2004

Authors: Varlet‐Marie, Emmanuelle | Brun, Jean‐Frederic

Article Type: Research Article

Abstract: Blood lactate increases during exercise. Although this increase was classically interpreted as a “Pasteur‐like effect” resulting from anaerobiosis, it is now clear that it mostly results from a shift in the balance of oxidation of substrates in the muscle, with carbohydrate becoming the predominant fuel. However, we have repeatedly observed that the rise in blood lactate during exercise is correlated to blood viscosity and red cell aggregation. More recently we investigated this issue with the modelling of postexercise lactate kinetics, that allows a fair evaluation of lactate production by muscles (γ1) and lactate disappearance (γ2). Postexercise red cell aggregation (Myrenne …M1) appears to be correlated to γ2. Thus microcirculatory adaptations influenced by red cell aggregation may influence lactate disposal, adding its effect to that of the balance between carbohydrates and fat. On the other hand, the rise in blood lactate seems to induce some alterations in erythrocyte rheology at exercise. Correlations between its concentrations during exercise and erythrocyte rigidity support the concept that lactate, at least when it rises above the 4 mmol.l−1 threshold impairs red cell deformability. Moreover, it seems that endurance training influences erythrocyte response to lactate. While lactate did not in vitro affect erythrocyte aggregation, it impaired (as expected) erythrocyte deformability in sedentary subjects but it (unexpectedly) improved it in trained subjects. This difference may be due to training‐induced adaptations in erythrocyte metabolism, including transmembrane transfer via monocarboxylate transporters which show marked alterations in this context. This specific training‐induced pattern of response to lactate may provide an alternative explanation to the exercise‐induced arterial hypoxemia that occurs in such athletes. Show more

Keywords: Blood viscosity, plasma viscosity, hemorheology, erythrocyte deformability, erythrocyte aggregability, exercise, lactate, cossover concept, anaerobic threshold

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 331-337, 2004

Authors: Brun, Jean‐Frédéric | Varlet‐Marie, Emmanuelle | Cassan, Delphine | Manetta, Jérôme | Mercier, Jacques

Article Type: Research Article

Abstract: We previously reported in rugbywomen correlations between RBC deformability and the ability to oxidize at exercise more lipids. This surprising finding might of course be spurious, or reflect the importance of the balance of substrates at exercise on baseline parameters that regulate blood rheology. Actually, the capacity of skeletal muscle to utilize either lipid or carbohydrate as fuels strongly influences whole body metabolism both at rest and during exercise. While the healthy skeletal muscle has substantial metabolic flexibility and is able to switch from predominantly lipid o oxidation during fasting or endurance exercise to increased glucose oxidation in conditions of …insulin stimulation, obese individuals and those with type 2 diabetes manifest higher lipid oxidation during insulin‐stimulated conditions despite lower rates of lipid oxidation during fasting or prolonged exercise. A low ability to oxidize and to periodically deplete triglyceride in muscle is associated with raised blood lipids. In addition, high carbohydrate oxidation rates in the mitochondrion are likely to promote more free radical generation. An increase in either blood lipids or free radicals is likely to induce profound hemorheological effects. We present here hemorheological studies in various populations with the use of exercise calorimetry in order to assess this switch of substrates. These studies further evidence negative correlations between the ability to oxidize lipids at exercise and parameters of blood viscosity. Correlations found between RBC deformability and the ability to oxidize at exercise more lipids may be due to effects of endurance training on lipid oxidation which may in turn modify both lipid metabolism and free radical generation, thus influencing RBC rheology. Show more

Keywords: Blood viscosity, hemorheology, erythrocyte deformability, erythrocyte aggregability, substrate oxidation, mitochon‐ drion, crossover concept

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 339-343, 2004