Biorheology - Volume 40, issue 1-3

Authors: Blondel, Walter C.P.M. | Lehalle, Bertrand | Lercher, Marie‐Noëlle | Dumas, Dominique | Bensoussan, Danielle | Stoltz, Jean‐François

Article Type: Research Article

Abstract: The aim of this study was to determine the comparative three‐dimensional mechanical properties of healthy and atherosclerotic muscular human arteries. Using a previously developed experimental system, in vitro inflation tests were performed on twelve segments of arteries, in static conditions. Two different initial states were used to carry the mechanical study through (large deformation, thick‐walled). Main significant differences between healthy and atherosclerotic tested segments are observed for axial traction force whatever the initial state and radial and circumferencial strains referenced to longitudinally pre‐stretched state. We showed that strain energy allows to differentiate between both types of arteries only when absolute …values of transversal components were considered. Differential values of energy were not discriminating. Our results also show the potential interest of studying arteries in vivo at low transmural pressure. Show more

Keywords: Wall rheology, inflation tests, unloaded state, human artery, atherosclerosis

Citation: Biorheology, vol. 40, no. 1-3, pp. 369-376, 2003

Authors: van de Lest, Chris H.A. | Brama, Pieter A.J. | van Weeren, P.R.

Article Type: Research Article

Abstract: This study aimed at the determination of the influence of exercise on the levels of a number of bone morphogenic enzymes in subchondral bone and at the comparison of these data with other (subchondral) bone‐related parameters that have been investigated in the same experimental population. Forty‐three foals were reared until weaning at 5 months of age under similar conditions, except for the type and amount of exercise. Fifteen foals remained at pasture (Pasture group and also control group), 14 foals were kept in box stalls (Box group) and 14 foals were kept in the same box stalls but were …subjected daily to an increasing number of gallop sprints (Training group). After weaning 8 foals from each group were euthanised. All remaining 19 animals were housed together in a loose box with access to a small paddock to study a possible reversibility of exercise‐induced effects. Post mortem subchondral bone samples were collected from the femoropatellar joint and analysed for the bone morphogenic enzymes alkaline phosphatase (ALP), tartrate resistant acid phosphatase (TRAP) and lysyl oxidase (LO). Data were compared to calcium content, numbers of collagen cross‐links, bone mineral density (BMD) and cross‐sectional area (CSA) collected in other bone‐related studies in the same group of experimental animals. At 5 months of age, ALP levels were significantly lower and TRAP levels higher in both the Box and the Training group, making the ALP : TRAP ratio reversed in relation to the Pasture group. LO levels were lower in the Box group only. The ALP and TRAP data corresponded with changes in CSA, but not with calcium and BMD, the levels of which were the same in the Training and Pasture groups. The LO levels corresponded nicely with hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) cross‐links. At 11 months of age ALP and TRAP levels had reached similar levels in most groups, normalising the ALP : TRAP ratio. TRAP levels in the former Training group lagged somewhat behind. LO levels were still significantly lower in the former Box rest group. It is concluded that the overall increase in bone mass (characterised by the change in CSA) is apparently related to continuous, evenly distributed exercise as in the Pasture group (natural situation). This process seems to be related with ALP and TRAP levels and their ratio. For normal cross‐link levels and BMD, short heavy bouts of exercise superimposed on a basic rest regimen seem sufficient. However, both data from this study and from earlier studies suggest that this latter exercise regimen might have a long‐term deleterious effect. Show more

Citation: Biorheology, vol. 40, no. 1-3, pp. 377-382, 2003

Authors: Bouten, Carlijn V.C. | Breuls, Roel G.M. | Peeters, Emiel A.G. | Oomens, Cees W.J. | Baaijens, Frank P.T.

Article Type: Research Article

Abstract: Skeletal muscle tissue is highly susceptible to sustained compressive straining, eventually leading to tissue breakdown in the form of pressure sores. This breakdown begins at the cellular level and is believed to be triggered by sustained cell deformation. To study the relationship between compressive strain‐induced muscle cell deformation and damage, and to investigate the role of cell–cell interactions, cell–matrix interactions and tissue geometry in this process, in vitro models of single cells, monolayers and 3D tissue analogs under compression are being developed. Compression is induced using specially designed loading devices, while cell deformation is visualised with confocal microscopy. Cell damage …is assessed from viability tests, vital microscopy and histological or biochemical analyses. Preliminary results from a 3D cell seeded agarose model indicate that cell deformation is indeed an important trigger for cell damage; sustained compression of the model at 20% strain results in a significant increase in cell damage with time of compression, whereas damage in unstrained controls remains constant over time. Show more

Citation: Biorheology, vol. 40, no. 1-3, pp. 383-388, 2003

Authors: Traoré, Mariama | Jialing, Hong | Chunling, Xu

Article Type: Research Article

Abstract: Objective: To further establish a definite basic of the application value of sodium ferulate (SF) for prevention and cure of acute coronary heart disease, we examined the effects of SF on LDL oxidation and lipid accumulation in rabbit aortic smooth muscle cells induced by modified‐LDL. Methods: LDL oxidation was carried out in the presence and absence of SF. Cultured rabbit aortic smooth muscle cells were used as the model. To investigate the effects of SF on intracellular lipid accumulation, cells were incubated with Ox‐LDL and SF. The lipid content (cholesterol and triglycerides) of the cells were determined. Results: …Intracellular cholesterol and triglycerides were significantly increased in cell‐modified LDL group. The enhancements of above indexes were decreased after addition of SF (200 μg/ml). On the other hand, incubation of LDL with SF resulted in a significant decrease in TBARS activity and electrophoretic mobility. Conclusion: The results indicated that SF assume significance both in the protection of LDL against oxidation and inhibition of cell‐modified LDL effects on intracellular lipid with the potential to prevent cell foamation. Show more

Keywords: Oxidized low density lipoproteins, foam cells, atherosclerosis, sodium ferulate

Citation: Biorheology, vol. 40, no. 1-3, pp. 389-394, 2003

Authors: Jing‐ping, Ou‐yang | Baohua, Wang | Yongming, Liu | Lei, Wei | Jingwei, Yang

Article Type: Research Article

Abstract: The aim of this article was to examine the protective effect of Chinese traditional medicine angelica on human umbilical vein endothelial cells (HUVECs, ECV304 ) from injury induced by hyperlipidemic serum (HLS) and to study the underlying mechanism. Spectrophotometer and immunocytochemical methods were used to detect the content of nitric oxide (NO) in suspension and expression of intercellular adhesion molecule‐1 (ICAM‐1), transforming growth factor β1 (TGFβ1 ), basic fibroblast growth factor (bFGF) on the cell surface, respectively. After incubated with 50 μl/ml HLS for 24 hours, expression of ICAM‐1 and bFGF in ECs was significantly increased, while expression of …TGFβ1 and the release of NO from ECs were significantly decreased. All these effect of HLS on ECs can be reversed by angelica significantly. The above effect of angelica may be related to its anti‐atherosclerotic action. Our findings provided experimental basement for the clinical application of angelica to prevent the development of atherosclerosis. Show more

Keywords: Angelica, vascular endothelial cell, ICAM‐1, TGF$\beta_{1}$, bFGF, NO, atherosclerosis

Citation: Biorheology, vol. 40, no. 1-3, pp. 395-399, 2003

Authors: Lusardi, Theresa A. | Smith, Douglas H. | Wolf, John A. | Meaney, David F.

Article Type: Research Article

Abstract: In this study, we examine the response of cultured hippocampal neurons to mechanical stretch. To measure the immediate response, we measured the response of a calcium sensitive fluorescent dye (Fura‐2AM) prior to and for five minutes following stretch. In separate experiments, we measured the viability of the cells using propidium iodide labeling at 24 hours following a single stretch. Results show that cytosolic calcium increases immediately following stretch to levels much higher than those associated with maximal chemical agonist (NMDA) stimulation. Moreover, the calcium response data indicate a loss in calcium regulation in the neurons at the most severe level …of stretch. Finally, at the highest levels of stretch, the cell survivability decreases at 24 hrs following the stretch injury. These data show the association between loss in calcium regulation and early signs of neuronal cell death. Show more

Citation: Biorheology, vol. 40, no. 1-3, pp. 401-409, 2003

Authors: Tran, Nguyen | Li, Yan | Bertrand, Sylvie | Bangratz, Sébastien | Carteaux, Jean‐Pierre | Stoltz, Jean‐François | Villemot, Jean‐Pierre

Article Type: Research Article

Abstract: The promising concept of cell transplantation and cardiac tissue engineering has been developed in the last few years and focused on strategies attempting to replace dysfunctional, necrotic, and/or apoptotic cardiomyocytes with new cells of mesodermal origin. Transplantation of autologous cells minimizes the risk of neoplasia and avoids immune rejection associated with allogenic or xenogenic cells and recent data hold enormous hopes for short term clinical practices. Tissue engineering represents another promising approach that makes possible the creation of new functional tissues to replace the lost or failing one. Three‐dimensional polymeric scaffolds provide the mechanical support for the candidate cells until …the formation of cardiac‐like tissue prior to surgical repair of the infarcted myocardium. For ultimate clinical applications, further investigations have to select the appropriate cell types, to determine the sufficient number of grafted cells and to provide the long term evaluation of these strategies in the global improvements of cardiac function (neoangiogenesis, synchronous contraction and extracellular matrix remodelling). Show more

Keywords: Cell transplantation, autologous cell, tissue engineering, heart failure

Citation: Biorheology, vol. 40, no. 1-3, pp. 411-415, 2003

Authors: Richardson, Peter D.

Article Type: Research Article

Abstract: Relatively little attention has been given to vessel wall mechanics in interaction with the pulsatile fluid motion of blood in the epicardial coronary arteries which are prone to atherosclerotic plaque development. Theories for lipid transport by convective effects, while appealing in many ways, do not serve to explain the predominantly bounded, elliptic profiles of atherosclerotic plaques when examined en face at gross autopsy. This paper outlines how structural–mechanical concepts relating to plaque shapes (starting from the shapes available even with isometric shell peeling to create the cavities typical of early plaques) can be combined with understanding of the blood pressure …distribution which develops in the vicinity of a predominantly T‐junction in a blood vessel to modulate and interact in shape formation by cyclic, local flexure. This provides a foundation for a rational hypothesis to be tested in vivo with bi‐plane angiography and vessel wall imaging, e.g., intravascular ultrasound, to better assess the roles of solid and fluid mechanics in the localization of plaques. Show more

Citation: Biorheology, vol. 40, no. 1-3, pp. 417-421, 2003

Authors: Remuzzi, Andrea | Ene‐Iordache, Bogdan | Mosconi, Lidia | Bruno, Simona | Anghileri, Abramo | Antiga, Luca | Remuzzi, Giuseppe

Article Type: Research Article

Abstract: It has been extensively documented that changes in blood flow induce vascular remodeling and this phenomenon seems to be correlated to the shear forces imposed on the vessel wall by motion of blood. Wall shear stress, the tractive force that acts on the endothelium, has been shown to influence endothelial cell function. To study changes in wall shear stress that develop on the vessel wall upon changes of blood flow, we set up a technique that allows estimation of shear stress in the radial artery of patients on chronic hemodialysis therapy. The technique is based on color‐flow Doppler examination of …the radial artery before and after surgical creation of radiocephalic fistula for hemodialysis. Calculation of time function wall shear stress and blood flow rate in the radial artery is performed on the basis of arterial diameter, center‐line velocity waveform and blood viscosity, using a numerical method developed according to Womersley's theory for pulsatile flow in tubes. The results presented confirm that the model developed is suitable for calculation of the wall shear stress that develops in the radial artery of patients before and after surgical creation of an arteriovenous fistula for hemodialysis. This methodology was developed for characterization of wall shear stress in the radial artery but may be well applied to other vessels that can be examined by echo‐Doppler technique. Show more

Citation: Biorheology, vol. 40, no. 1-3, pp. 423-430, 2003