Clinical Hemorheology and Microcirculation - Volume 35, issue 1-2

Authors: Pais, Eszter | Alexy, Tamas | Holsworth, Jr., Ralph E. | Meiselman, Herbert J.

Article Type: Research Article

Abstract: The vegetable cheese-like food, natto, is extremely popular in Japan with a history extending back over 1000 years. A fibrinolytic enzyme, termed nattokinase, can be extracted from natto; the enzyme is a subtilisin-like serine protease composed of 275 amino acid residues and has a molecular weight of 27.7 kDa. In vitro and in vivo studies have consistently demonstrated the potent pro-fibrinolytic effect of the enzyme. However, no studies to date have evaluated the effects of nattokinase on various hemorheological parameters and thus we have begun to assess the effects of the enzyme on RBC aggregation and blood viscosity. Blood samples …were incubated with nattokinase (final activities of 0, 15.6, 31.3, 62.5 and 125 units/ml) for 30 minutes at 37°C. RBC aggregation was measured using a Myrenne MA-1 aggregometer and blood viscosity assessed over 1–1000 s−1 with a computer controlled scanning capillary rheometer (Rheolog® ). Our in vitro results showed a significant, dose-dependent decrease of RBC aggregation and low-shear viscosity, with these beneficial effects evident at concentrations similar to those achieved in previous in vivo animal trials. Our preliminary data thus indicate positive in vitro hemorheological effects of nattokinase, and suggest its potential value as a therapeutic agent and the need for additional studies and clinical trials. Show more

Keywords: Nattokinase, red blood cell, aggregation, hemorheology

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 139-142, 2006

Authors: Yerer, M. Betül | Aydoğan, Sami

Article Type: Research Article

Abstract: The hormone melatonin, secreted from the pineal gland at night and suppressed during the day, provides a circadian and seasonal signal to the organism. The impact of pharmacological doses of melatonin on erythrocyte deformability was investigated by our group in several studies in both in vitro and in vivo conditions. The aim of this study was to investigate the effects of alterations in the physiological melatonin levels via the circadian rhythm on erythrocyte deformability. 50 male rats weighing 250–300 g were divided in 5 groups. The rats were subjected to 12/12, 24/0, 0/24, 16/8 and 8/16 h of Light/Dark (L/D) …cycle, respectively. The elongation indexes (EI) of the erythrocytes were measured by a laser diffractometer (Myrenne Rheodyne SSD) by using 30 μl of whole blood suspended in 2 ml of Dextran 60. There was no significant difference in the EI of the 24/0 h L/D group compared to the control (12/12), whereas the decrease of EI was statistically important in the 0/24 h L/D group (p=0.009). This decrease in EI was also significant when this group was compared to the 24/0 h L/D group (p=0.05). Furthermore, the EI was affected significantly by alterations in the circadian rhythm, compared to control (16/8, 8/16 h L/D; p=0.05 and p=0.007, respectively). As a result, the alterations in physiological melatonin levels via different circadian rhythms have significant impacts on the deformability of erythrocytes, which therefore may cause important cardiovascular implications in the people who are exposed to different light dark cycles. Furthermore, these data represents a new and a quite crucial open-field to be investigated and taken into account in in vivo hemorheological studies. Show more

Keywords: Erythrocyte deformability, shear stress, melatonin, circadian rhythm

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 143-147, 2006

Authors: Cicco, Giuseppe | Vetrugno, Michele | Rotelli, Maria Teresa | Sborgia, Giancarlo | Pennetta, Massimiliano | Vico, Pier Paolo | Memeo, Vincenzo | Nitti, Luigi | Sborgia, Carlo

Article Type: Research Article

Abstract: Background: Glaucoma is currently attributed to two different possible pathogenetic mechanisms: mechanical (the ocular damage is induced by physical injury), and vascular (the ocular damage is sustained by ischemia of the optic nerve head). Aim: We considered the possibility that several anti-glaucoma drugs (β-blockers, carbonic anhydrase inhibitors and prostaglandins) could have an influence on optic nerve head hemorheology and oxygen supply. Materials and method: We studied 4 groups of 10 subjects each: a control group, and 3 primary open angle glaucoma (POAG) groups, treated with topical β-blockers, (10 patients), carbonic anhydrase inhibitors (CAI), and prostaglandin analogs (PG), respectively. In these …4 groups we investigated the RBC surface AchE and cytosolic calcium levels in order to assess their possible influence on the hemorheology and microcirculation in optic nerve head blood perfusion. Results: A significant correlation (p<0.048) was found between the RBC surface acetylcholinesterase and RBC intracytosolic calcium values in patients with POAG treated with β-blockers. We found no significant correlation (p=n.s.) between the same patterns in the other Groups or in Controls. Conclusion: These data indicate that CAI and PG drugs do not interfere with AchE in POAG patients, whereas β-blockers negatively affect the RBC deformability. Show more

Keywords: Hemorheology, glaucoma, β-blockers, carbonic anhydrase inhibitors, prostaglandins

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 149-154, 2006

Authors: Velcheva, Irena | Antonova, Nadia | Dimitrova, Valentina | Dimitrov, Nikolay | Ivanov, Ivan

Article Type: Research Article

Abstract: It is known that plasma lipids could increase the cerebrovascular risk through alteration of the hemorheological profile. The aim of the study was to evaluate the relationship between blood viscosity parameters and plasma lipids in patients with cerebrovascular disease (CVD). The study included 43 patients with transient ischemic attacks (TIAs), 53 patients with chronic unilateral cerebral infarctions (UCI) and 57 patients with risk factors (RF) for CVD. Whole blood viscosity (WBV) at different shear rates by Couette rotational viscometer Contraves Low Shear 30, plasma viscosity (PV) with capillary viscometer, hematocrit (Hct), fibrinogen (Fib), Cholesterol (Chol), triglycerides (Tg) and high-density lipoproteins …(HDL) were examined in all patients and in a control group of 56 presumed healthy subjects. The hemorheological results showed increase of Hct, Fib, WBV and PV in the patients with TIAs and UCI; it was more pronounced in the UCI patients. Significant increase of Hct and WBV in the group with RF for CVD was also found. The elevation of Chol and Tg predominated in the patients with UCI and in the subjects with RF for CVD. These lipid variables correlated significantly with PV in the TIAs and RF for CVD groups. Conclusion is drawn about the significance of plasma Tg for decrease of blood fluidity and for impairment of the cerebral circulation in CVD. Show more

Keywords: Cerebrovascular disease, plasma lipids, blood and plasma viscosity

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 155-157, 2006

Authors: Ahmadizad, Sajad | El-Sayed, Mahmoud S. | MacLaren, Donald P.M.

Article Type: Research Article

Abstract: The present study was designed to investigate the effects of resistance exercise and recovery on platelet activation and function. Twenty one healthy male subjects (27.9±4.8 years) completed three sets of five to seven repetitions of six exercises at an intensity corresponding to 80% of one repetition maximum (1RM), which was followed by 30 minutes recovery. Venous blood samples (20 ml) were obtained before, immediately after exercise and at the end of recovery and were analysed for platelet indices, platelet aggregation using collagen and various final concentrations of adenosine-5′-diphosphate (ADP), and beta thromboglobulin (B-TG). Resistance exercise was followed by a significant …increase in corrected platelet count, corrected plateletcrit, and B-TG. These increases were transient and decreased to pre-exercise level at the end of recovery. When plasma samples were not corrected for changes in platelet count, exercise was followed by a significant increase (P<0.05) in platelet aggregation using high concentration of ADP. With corrected samples, platelet aggregation and B-TG were not altered after exercise and recovery. It was concluded that heavy resistance exercise induces in vivo activation of platelets as manifested by an increase in platelet aggregation and a rise in B-TG and that these changes could be explained partially by changes in plasma volume and platelet count induced by exercise. Show more

Keywords: Resistance exercise, recovery, platelet function, B-TG, platelet count

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 159-168, 2006

Authors: Gori, Tommaso | Di Stolfo, Giuseppe | Sicuro, Silvia | Dragoni, Saverio | Parker, John D. | Forconi, Sandro

Article Type: Research Article

Abstract: Although microvascular dysfunction is of critical importance in the pathophysiology of myocardial ischemic syndromes, no study has investigated whether there are differences in the sensitivity to ischemia and reperfusion injury between microvessels and conduit arteries. Ten healthy young nonsmoking male volunteers (age range 24–45) were enrolled. Parameters measured included radial (conduit) artery (endothelium-dependent) flow-mediated dilation, microvascular cutaneous reactive hyperemia (using laser Doppler) and acetylcholine-induced microvascular vasodilation (laser Doppler iontophoresis). Data were acquired before and after ischemic injury (15 minutes of ischemia of the brachial artery followed by 15 minutes reperfusion) and analyzed in a randomized, blinded fashion. Conduit artery FMD …was significantly blunted after ischemia (before: 7.5±1.1%; after: 2.9±1.0%, P<0.05). Conversely, ischemia had no effect on microvascular reactive hyperemia (P=ns) and acetylcholine-induced vasodilation (P=ns). Using a human in vivo model, we demonstrate that microvessels are more resistant to ischemic injury as compared to conduit arteries. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 169-173, 2006

Authors: Mannini, Lucia | Marcucci, Rossella | Paniccia, Rita | Antonucci, Emilia | Giglioli, Cristina | Valente, Serafina | Gori, Anna Maria | Prisco, Domenico | Gensini, Gian Franco | Abbate, Rosanna

Article Type: Research Article

Abstract: Recently the phenomenon of aspirin resistance has been object of several studies, but no data are available on the possible role of the haemorheologic parameters in affecting platelet function and resistance to antiplatelet agents. Aim of our study was to evaluate platelet function and haemorheology in patients with acute coronary syndromes (ACS), receiving double antiplatelet therapy with aspirin and clopidogrel. The study population included 301 (231M/70F; age: 66±13 yrs) consecutive adult patients admitted to the Coronary Care Unit of the Azienda Ospedaliero-Universitaria Careggi, with diagnosis of acute myocardial infarction or unstable angina. We assessed: whole blood viscosity (WBV) at shear …rates of 0.512 s−1 and 94.5 s−1 , plasma viscosity (PLV) at 94.5 s−1 shear rate, erythrocyte deformability index (DI) and PFA-100 closure times with ADP (PFA/ADP) and epinephrine (PFA/EPI). We considered any PFA-100-EPI result <203 sec (95th percentile of control distribution) to be indicative of aspirin resistance. 104/301 patients (34.5%) had PFA/EPI CTs in the reference range (group 1) whereas the remaining had values higher than 203 sec (group 2). WBV at 94.5 sec −1 s.r. was similar in group 1 and 2 (WBV: 4.43±0.25 vs 4.45±0.61 mPa·sec, respectively). PLV and WBV at 0.512 sec −1 s.r. were slightly higher, but not significantly, in group 1 than in group 2 (PLV: 1.47±0.13 vs 1.44±0.15 mPa·sec; p=0.08 and WBV: 23.37±4.6 vs 22.54±3.90 mPa·sec; p=0.07). DI was significantly lower in group 1 with respect to group 2 (4.05±2.93 vs 5.71±3.30, p<0.0001). White blood count (WBC) was significantly higher in group 1 than in group 2 (11464±3504 vs 7867±2162, p<0.0001). In conclusion, these results demonstrate that in patients with acute coronary syndromes the antiaggregant effect of aspirin is modulated not only by the direct action on platelets, but also by erythrocyte deformability and white blood cell count. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 175-181, 2006

Authors: Cortinovis, A. | Crippa, A. | Cavalli, R. | Corti, M. | Cattaneo, L.

Article Type: Research Article

Abstract: As known, at the arteriolar level there is the highest resistance to the flow due to the section and to the velocity with an average pressure fall of 50 mmHg (from 85 to 35 mmHg). This resistance is expressed in sec−1 by the ratio W/2r. This ratio is very high with an average value of 332 sec−1 and viscosity at this high shear-rate is negligible. At the capillary level the pressure fall is 11.5 mmHg but the vascular resistance W/2r is much lower, on average 32 sec−1 . We can say that if a resistance of 333 sec−1 …corresponds with a pressure fall of 50 mmHg, then a resistance of 32 sec−1 should correspond with a pressure fall of 4.8 mmHg. The highest pressure fall is due to another kind of resistance which we can define as “Capillary Blood Viscosity” because it depends on the rheological and structural characteristics of the blood. Our instrument reproduces the structure of the capillary district in an experimental model and measures the General Blood Viscosity (GBV) and the Capillary Blood Viscosity (CBV) at the same shear-rate and in particular at the low shear-rate when in non-Newtonian fluids the highest increase in viscosity appears. Consequently, at the capillary, viscosity is dominant with respect to the other geometric and physical resistances. Moreover, the percentage ratio between the GBV and the CBV gives a physical measure of erythrocyte deformability. Knowing viscosity at shear-rate present in the circulatory system, we can obtain the size of RBCs aggregates in the different circulatory districts and their characteristics expressed like “aggregation bond”. Changes in CBV are the only possibility in clinical practice to improve the circulatory flow in the capillary district because it is not sure that changes in the arteriolar section can improve the capillary flow or rather open arterio-venous anastomosis. Moreover, in the systemic circulation the aggregate size allows us to point out the phenomenon of cell adhesion because the presence of several receptors involves also the other blood cells. Finally the size and the stability of the RBCs aggregates can modify the endothelial thrombo-resistance. Show more

Keywords: General blood viscosity, capillary blood viscosity, erythrocyte deformability, erythrocyte aggregation, microcirculation

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 183-192, 2006

Authors: Velcheva, Irena | Antonova, Nadia | Titianova, Ekaterina | Damianov, Petar | Dimitrov, Nikolay | Ivanov, Ivan

Article Type: Research Article

Abstract: The study aimed to follow the relationship between some hemorheological variables and the main risk factors (RF) for carotid atherosclerosis (CA). Carotid atherosclerosis was evaluated by color duplex sonography of the carotid arteries in 18 patients with RF for CA, 31 patients with transient ischemic attacks (TIAs), 21 patients with chronic unilateral cerebral infarctions (UCI) and 11 healthy subjects without RF for CA. The examined hemorheological variables were whole blood and plasma viscosity, hematocrit and fibrinogen. They were correlated with intima-media thickness (IMT) of the common carotid and the internal carotid arteries and with other main RF for CA: hypertension, …diabetes mellitus, coronary heart disease, and hyperlipidemia. The hemorheological investigation showed an increase in blood and plasma viscosity at different shear rates and it was more expressed in the group with UCI. The neurosonographic investigation revealed an increase in the IMT and carotid artery stenoses in the patients' groups with CVD. These were also more frequent in the patients with UCI. Different correlations were established between the hemorheological parameters, the IMT of the carotid arteries and other RF for CA. In the group with UCI, the hematocrit and the whole blood viscosity correlated significantly with the IMT, arterial blood pressure and cholesterol values. These data confirm the influence of the hemorheological parameters on carotid blood vessel walls and on blood flow in patients with CVD. Show more

Keywords: Blood and plasma viscosity, risk factors, carotid atherosclerosis, carotid intima media thickness

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 195-198, 2006

Authors: Lo Presti, Rosalia | Tozzi Ciancarelli, Maria Giuliana | Canino, Baldassare | Carollo, Caterina | Lucido, Daniela | Amodeo, Gabriella | Romano, Adele | Caimi, Gregorio

Article Type: Research Article

Abstract: An abnormal activation state of polymorphonuclear leukocytes (PMN) plays a key role in organ injury induced by vascular atherosclerotic disease (VAD) and diabetes mellitus (DM). PMN membrane fluidity and cytosolic Ca2+ content can be considered markers of PMN activation. In this research we evaluated the PMN membrane fluidity and cytosolic Ca2+ content in VAD subjects with and without type 2 DM and examined the association between these parameters and the mono- or polyvascular localization. We enrolled 155 VAD subjects, including 92 non-diabetic (group A: mean age 63.6±9.2 years) and 63 diabetic patients (group B: mean age 65.4±7.8 years). …Among group A 63 patients had monovascular and 29 polyvascular disease; among group B 30 patients had monovascular and 22 polyvascular disease. In each patient we evaluated the PMN membrane fluidity labelling the cells with the fluorescent probe 1,4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH) and the PMN cytosolic Ca2+ content marking the cells with the fluorescent probe Fura 2-AM. PMN membrane fluidity did not discriminate normal subjects from diabetic and non-diabetic VAD subjects, while cytosolic Ca2+ content was increased in both groups. PMN membrane fluidity did not distinguish normal subjects from mono- or polyvascular VAD patients with and without type 2 DM. PMN cytosolic Ca2+ content was increased especially in monovascular VAD patients; both mono- and polyvascular VAD subjects with DM had a PMN cytosolic Ca2+ content higher than normals. Our results show the presence of an increased PMN cytosolic Ca2+ content in diabetic and non-diabetic VAD subjects but no association was observed between this increase and the mono- or polyvascular localization. Show more

Keywords: Vascular atherosclerotic disease, type 2 diabetes mellitus, polymorphonuclear leukocyte membrane fluidity, polymorphonuclear leukocyte Ca$^{2+}$ content

Citation: Clinical Hemorheology and Microcirculation, vol. 35, no. 1-2, pp. 199-201, 2006