Clinical Hemorheology and Microcirculation - Volume 46, issue 1

Authors: Hazer, Derya Burcu | Berker, Mustafa | Narin, Firat | Ileri-Gurel, Esin | Basak, Ahmet Tulgar | Seringec, Nurten | Kaymaz, Figen | Dikmenoglu, Neslihan | Tuncel, Murvet

Article Type: Research Article

Abstract: Pravastatin has neuroprotective effects against aging but its role in brain injury remains unclear. This study evaluated the effects of pravastatin on the ultrastructural changes and hemorheological parameters in rats after traumatic brain injury (TBI) of right parietal cortical contusion by a controlled weight-dropping method. There were three groups: (I) Sham operated group; (II) TBI + vehicle (saline) group; and (III) TBI + pravastatin group. Right parietal craniectomy was performed in all groups. In TBI + pravastatin group, pravastatin was administered orally at a dose of 1 mg/kg every day for 7 days starting at 24 hours after the injury. …Plasma viscosity, erythrocyte deformability and erythrocyte aggregation were measured from blood samples of all rats on 2nd, 7th and 15th days. At the same time electron microscopic study was done on designated days for groups II and III. Treatment with pravastatin markedly increased aggregation amplitude and γIsc max values and significantly decreased erythrocyte deformability but did not change plasma viscosity in 2 weeks time. Ultrastructural parameters such as perinuclear edema, mitochondrial swelling and intraneuronal vacuoles were detected in lower degree in the statin group when compared to the saline group, especially decreased demyelinization and endothelial detachment was prominent. As a result, the hyperviscosity state with increased erythrocyte aggregation and decreased erythrocyte deformability induced by pravastatin in this study was accompanied by an improvement of the ultrastructural findings in TBI. This hyperviscosity state may be a compensatory mechanism to increase the oxygenation of the injured tissue by inducing the release of antiaggregant and vasodilatory substances by increasing shear stress. Therefore, we suggest that prolonged pravastatin usage may exert affirmative effects on traumatic brain injury conditions by increasing blood viscosity. Show more

Keywords: pravastatin, brain injury, erythrocyte aggregation, erythrocyte deformability, cellular ultrastructure, plasma viscosity

DOI: 10.3233/CH-2010-1328

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 1-11, 2010

Authors: El-Sayed, Mahmoud S. | Omar, Ayad Abuelgasem | Ali, Nagia

Article Type: Research Article

Abstract: To ascertain the effects of environmental temperature on blood rheology, ten subjects performed two exercise trials, in random order, at approximately 60% VO2 max for 45-min. One trial was conducted in thermoneutral environment (20 ± 1°C), while the other was performed in hot dry condition (36 ± 1°C). Venous blood was removed at rest; following exercise and recovery. Blood was measured for lactate, haematocrit, and hemoglobin, while plasma was measured for viscosity, and fibrinogen. Plasma volume changes were estimated from Hct and Hb readings. Exercise was followed by a significant (P < 0.05) reduction in plasma volume in both …test trials. Lactate increased significantly (P < 0.05) following exercise with no difference being observed between trials. When post exercise raw data were not adjusted for plasma volume changes, a significant increase (P < 0.05) in plasma viscosity (PV) and plasma fibrinogen (Fb) was found with no difference between thermoneutral and hot trials. When the raw data post exercise for PV and Fb were adjusted for plasma volume changes, no significant difference between rest and post exercise was demonstrated. Rheological variables returned to the pre-exercise level at the end of recovery. In conclusion, vigorous exercise transiently increased PV and Fb, and the added heat stress did not affect these responses more than exercise alone. The mechanism responsible for the increase in PV and Fb in response to vigorous exercise appears to be related to plasma shifts from intravascular to the extravascular spaces rather than plasma volume loss. Show more

Keywords: Exercise, heat, plasma viscosity, plasma fibrinogen, plasma volume

DOI: 10.3233/CH-2010-1329

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 13-21, 2010

Authors: Heinle, H. | Tober, C. | Zhang, D. | Jäggi, R. | Kuebler, W.M.

Article Type: Research Article

Abstract: Vertigo of various and often unknown aetiologies has been associated with and attributed to impaired microvascular perfusion in the inner ear or the vertebrobasilar system. Vertigoheel is a low-dose combination preparation of proven value in the symptomatic treatment of vertigo. In the present study we tested the hypothesis that Vertigoheel’s anti-vertiginous properties may in part be due to a vasodilatory effect exerted via stimulation of the adenylate and/or guanylate cyclase pathways. Thus, the influence of Vertigoheel or its single constituents on synthesis and degradation of cyclic nucleotides was measured. Furthermore, vessel myography was used to observe the effect of Vertigoheel …on the vasoreactivity of rat carotid arteries. Vertigoheel and one of its constituents, Anamirta cocculus, stimulated adenylate cyclase activity, while another constituent, Conium maculatum, inhibited phosphodiesterase 5, suggesting that the individual constituents of Vertigoheel contribute differentially to a synergistic stimulation of cyclic nucleotide signalling pathways. In rat carotid artery rings, Vertigoheel counteracted phenylephrine-induced tonic vasoconstriction. The present data demonstrate a vasorelaxant effect of Vertigoheel that goes along with a synergistic stimulation of cyclic nucleotide pathways and may provide a mechanistic basis for the documented anti-vertiginous effects of this combination preparation. Show more

Keywords: Vertigo, Vertigoheel, Vasoregulation, Vasorelaxation, signalling pathways, cyclic nucleotides, adenylate cyclase, phosphodiesterase 5, myography

DOI: 10.3233/CH-2010-1330

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 23-35, 2010

Authors: Richter, Joern | Zhou, Juan | Pavlovic, Dragan | Scheibe, Ricardo | Bac, Vo Hoai | Blumenthal, Johanna | Hung, Orlando | Murphy, Michael F. | Whynot, Sara | Lehmann, Christian

Article Type: Research Article

Abstract: Background: Antibiotic treatment represents a key component of therapy for severe sepsis. Apart from their antimicrobial efficacy, when choosing antibiotics in septic conditions, vasomodulatory effects should also be taken into account. Objectives: Aim of this study was to evaluate the vasomodulatory effects of vancomycin (VANCO) and tobramycin (TOBRA) in experimental endotoxemia by using intravital microscopy (IVM) of the intestinal microcirculation and measurements of the arterial contractility in vitro. Methods: Endotoxemia was induced in rats by intravenous administration of lipopolysaccharide (LPS). VANCO or TOBRA were given immediately after LPS administration. Intestinal functional capillary density (FCD) and leukocyte-endothelial interactions were evaluated by …IVM 2 hrs after LPS challenge. The effects of the antibiotics on the motility of aortal rings were examined in vitro. Results: Leukocyte adhesion was significantly potentiated in the LPS group and in both antibiotic groups as compared to control group. Roller flow in V1 and V3 venules increased in antibiotic treated groups as compared to untreated LPS animals. FCD in the longitudinal muscular and mucosal layers decreased significantly in either endotoxemia or antibiotics treated rats. However, administration of VANCO ameliorated FCD in endotoxemic rats. Both antibiotics, in higher concentration, produced moderate relaxation of the arterial smooth muscle. Conclusion: Tobramycin and vancomycin did not affect the interaction between leukocytes and microvascular endothelium while vancomycin increased functional capillary density in the intestinal wall. Both antibiotics had direct relaxing effects on the vascular smooth muscle. Therefore, vancomycin and to lesser extent tobramycin may influence vascular tone and thereby affect microcirculation in endotoxemia and sepsis. Show more

Keywords: Vancomycin, tobramycin, sepsis, microcirculation, smooth muscle

DOI: 10.3233/CH-2010-1331

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 37-49, 2010

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

Article Type: Research Article

Abstract: In the present article the authors make an approach over the applications of dithiothreitol (DTT) in its different clinical-laboratory, potential and up-to-date sources. Dithiothreitol is a chemical reagent with a wide actuation spectrum not only from a laboratorial view but also from a therapeutic standpoint, more clinical and practical. DTT (i) is frequently used in a variety of experiences that involve proteins or peptides, protecting sulfhydryl groups from oxidation and reducing disulfide bonds between cysteines; (ii) is also used in the study of disulfide exchange reactions of protein disulfides; (iii) is able to keep glutathione in the reduced state; (iv) …acts as an “antidote” enabling the activity of detoxification systems; (v) participates in cellular mechanisms such as vesiculation, cell morphology, signal transduction pathways (hormone-‘like’ role), etc.; (vi) can be used in the treatment approach of diseases like cystinosis or medical conditions resulting from ion or metal toxicity. In erythrocytes, there’s literature pointing that DTT may trigger changes on the normal discoid shape following metabolic depletion, and additionally modulate the exovesiculation kinetics as demonstrated by us. The present article dissects in detail recent findings in our Unit concerning the DTT influence on human erythrocytes. Show more

Keywords: Dithiothreitol, erythrocyte, redox status, thiols

DOI: 10.3233/CH-2010-1332

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 51-56, 2010

Authors: Simmonds, Michael J. | Sabapathy, Surendran | Gass, Gregory C. | Marshall-Gradisnik, Sonya M. | Haseler, Luke J. | Christy, Rhys M. | Minahan, Clare L.

Article Type: Research Article

Abstract: Impaired heart rate variability (HRV)and haemorheology are independently associated with cardiovascular disease and diabetic complications. The aim of the present study was to investigate the relationships between parameters of HRV,and red blood cell (RBC) aggregation and deformability, in older women with type 2 diabetes. Twenty women (age 69 ± 2 yr) with uncomplicated type 2 diabetes and twenty controls (age 69 ± 3 yr) participated in the study. Beat-to-beat cardiac (RR) intervals over 5 min were analysed for HRV parameters in the time and frequency domains. Blood was sampled for RBC deformability, as well as RBC aggregation in two suspending …mediums: haematocrit adjusted plasma and 3% dextran 70. RBC aggregation was increased and HRV was impaired for those with type 2 diabetes when compared with control. RBC aggregation was negatively related to low frequency power of HRV, and was positively related to high frequency power of HRV, for subjects with type 2 diabetes. RBC deformability was positively related to HRV only for those with type 2 diabetes. Impaired haemorheology is associated with reduced HRV in older women with type 2 diabetes, suggesting changes in the microcirculation may result in impaired modulation of cardiac cycles. Show more

Keywords: Aggregation, autonomic, deformability, elderly, erythrocyte, red blood cell

DOI: 10.3233/CH-2010-1333

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 57-68, 2010

Authors: Chew, Stanley H. | Meighan (Smith) Tomic, M. | Cheung, Anthony T.W.

Article Type: Research Article

Abstract: Context: The etiology of Alzheimer’s disease (AD) is inconclusive. Treatments targeting amyloid have largely been unsuccessful. There is increasing evidence that vasculopathy may play an important pathogenic role in AD. Objective: Longitudinal measurements of whole blood viscosity (WBV) using a computer-assisted hemorheologic protocol and characterization of microvascular abnormalities using computer-assisted intravital microscopy (CAIM) are two objective methods adopted in this laboratory to noninvasively quantify vasculopathy in AD patients. A correlation of increased disease severity with worsened vasculopathy would further bolster a cause and effect relationship. A case report (Case 1) is presented to illustrate the usefulness of following an AD …patient with these noninvasive techniques to correlate disease progression with vasculopathy. Design: Patients were selected from a private practice setting who met the Diagnostic and Statistical Manual of Mental Disorders criteria for AD. The Rheolog™ , a computer-assisted scanning rheometer, was used to obtain longitudinal measurements of WBV. The microvascular abnormalities in the bulbar conjunctiva were quantified using a severity index (SI, scale 0–15). The patient was observed over a 4 year period from 2005 to 2008. Conclusion: This case study shows a correlation of disease progression in an AD patient with worsened vasculopathy. It illustrates the usefulness of WBV and CAIM as tools to quantify vasculopathy in AD patients and additionally suggests a pathogenetic role vasculopathy may play in concert with the amyloid hypothesis. Show more

DOI: 10.3233/CH-2010-1356

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 69-73, 2010

Article Type: Correction

DOI: 10.3233/CH-2010-1359

Citation: Clinical Hemorheology and Microcirculation, vol. 46, no. 1, pp. 75-75, 2010