Biorheology - Volume 56, issue 1

Authors: Pries, Axel R.

Article Type: Research Article

Abstract: The hemodynamics of the microcirculation reflect system properties of the involved components. The blood itself is a complex suspension of water, small and large molecules and different cell types. Under most conditions, its rheologic properties are dominated by the different behaviour of fluid and cellular compartments. When perfused through small-bore tubes or vessels, the suspension exhibits specific emergent properties. The Fahraeus-effect and the Fahreaeus-Lindqvist-effect result from the interaction of cellular particles with each other and with the vessel wall. Additional phenomena occur in vascular networks due to the uneven distribution of blood cells and blood plasma at divergent microvascular bifurcations. …In order to understand microvascular hemodynamics in vivo but also in artificial microfluidic geometries it is thus necessary to recognize the pertinent system properties on the level of the blood, the microvessels and the microvascular networks or perfused structures. Show more

Keywords: Fahraeus effect, Fahreaeus-Lindqvist-effect, phase separation, microvascular networks, microvascular bifurcation, model simulation

DOI: 10.3233/BIR-190207

Citation: Biorheology, vol. 56, no. 1, pp. 1-13, 2019

Authors: Alanazi, Asma | Munir, Hafsa | Alassiri, Mohammed | Ward, Lewis S.C. | McGettrick, Helen M. | Nash, Gerard B.

Article Type: Research Article

Abstract: BACKGROUND: Mesenchymal stem cells (MSC) are used in therapy, often by injection into the blood. OBJECTIVE: We aimed to compare the adhesive and migratory properties of MSC from umbilical cords (UCMSC), bone marrow (BMMSC) or trabecular bone (TBMSC), which might influence delivery to injured tissue. METHODS: MSC were perfused through glass capillaries coated with matrix proteins, collagen or fibronectin, or albumin. Adherent cells were counted microscopically and their spreading analysed over time. MSC migration through 8 μm pore filters coated with the same proteins was analysed. RESULTS: The number of MSC adhering to collagen was …greater than fibronectin, decreased as wall shear rate increased from 17 to 70 s−1 , and was in the order UCMSC>BMMSC>TBMSC. Conversely, spreading was more effective on fibronectin and was in the order BMMSC>TBMSC≥UCMSC. Migration was promoted by coating the lower surface of filters with either matrix protein, with UCMSC migrating more efficiently than BMMSC. CONCLUSIONS: MSC show origin-dependent variations in their efficiency of capture from flow and subsequent spreading or ability to migrate on matrix proteins. UCMSC showed most efficient capture from flow, which was followed by less spreading, but more rapid migration. These responses might be associated with more effective delivery from the circulation into damaged tissue. Show more

Keywords: Mesenchymal stem cells, cell adhesion, cell migration, collagen, fibronectin, umbilical cord, bone marrow

DOI: 10.3233/BIR-180185

Citation: Biorheology, vol. 56, no. 1, pp. 15-30, 2019

Authors: Yoon, Won Ho | Lee, Keyong Ho

Article Type: Research Article

Abstract: BACKGROUND: Tamarind seed polysaccharide (TSP) is used as a texturizing agent and a thickener in food and pharmaceutical products. There are no publications describing the addition of TSP to intra-articular injection formulations for arthritis. OBJECTIVE: The purpose of this study was to investigate the rheology and efficacy of the formulation of TSP with hyaluronic acid (HA) as a new material for injection for arthritis. METHODS: We investigated the viscoelastic properties of formulations of HA and TSP as potential lubricants for arthritis, and tested the improvement of right/left paw weight distribution in monosodium iodoacetate-induced arthritis in the …rat. RESULTS: HA formulations with 3% and 4% TSP showed improved rheological characteristics and were protected against changes induced by heat sterilization. Addition of TSP also reduced pain in the arthritis model, as evidenced by normalization of the distribution of paw weight. CONCLUSIONS: TSP is a potential material as a substitute for HA or in combination with HA for intra-articular injection for arthritis. Show more

Keywords: Hyaluronic acid, tamarind seed polysaccharide, storage modulus, loss modulus, arthritis

DOI: 10.3233/BIR-190208

Citation: Biorheology, vol. 56, no. 1, pp. 31-38, 2019

Authors: Kilbride, Peter | Rull, Marina Vazquez | Townsend, Adam | Wilson, Helen | Morris, John

Article Type: Research Article

Abstract: BACKGROUND: The rheology of shear thickening fluids is well characterized for many physical applications, however the literature surrounding biologically or cryobiologically compatible shear thickening fluids is less well understood. OBJECTIVE: This study examined fluids consisting of corn-derived hydroxyethyl starch with a variety of sugars and cryoprotectants to characterize their shear-rate viscosity relationship. The objective was to establish if cryobiologically relevant materials could be used to afford biologics protection through shear-thickening. RESULTS: Fluids consisting of 50% hydroxyethyl starch by weight exhibited shear thickening with a variety of cryoprotectants. Lowering the temperature of the fluid both reduced critical …shear rates and enhanced thickening magnitude. Starch derived from corn, wheat, and rice all exhibited non-Newtonian shear-dependent viscosity behaviour at 50% by weight in water. Between the starch sources however, the shear-rate viscosity relationship varied widely, with wheat-derived starch shear thinning, and the remaining starches forming shear thickening fluids. Different starch sources had different baseline viscosities, critical shear rates, and rates of viscosity increase. CONCLUSIONS:  This study established that shear thickening is compatible with cryobiologically relevant agents, particularly so at lower temperatures. This forms the basis for harnessing these phenomena in biological processes such as cryopreservation. Show more

Keywords: Cryopreservation, shear-thickening, starch, colloids, temperature-dependence

DOI: 10.3233/BIR-180196

Citation: Biorheology, vol. 56, no. 1, pp. 39-50, 2019

Authors: Bilgi, Coşkun | Atalık, Kunt

Article Type: Research Article

Abstract: BACKGROUND: Previous studies on aneurysm modeling have focused on the blood rheology and vessel elasticity separately. The combined effects of blood shear thinning properties and wall elasticity need to be revealed. OBJECTIVE: To provide insights on how pulsatile hemodynamics vary with blood rheology and vessel elasticity for a developed abdominal aortic aneurysm (AAA). METHOD: An Arbitrary Lagrangian-Eulerian fluid-solid interaction method is adopted with the Newtonian and the shear thinning Carreau constitutive models for the fluid with the linearly elastic and the hyperelastic Yeoh models for the vessel. Finite element based numerical solver is used to simulate …the blood flow in the AAA. RESULTS: Newtonian model overestimates the velocity values compared to the Carreau model and the difference in the velocity field increases as the shear rate decreases at the instances of the cardiac cycle. The rigid walled simulations display higher deviations in the velocity and wall shear stress with the fluid rheology. The risk indicators show that Newtonian assumption combined with the linearly elastic model may overlook degeneration risk of arterial tissue. CONCLUSIONS: Newtonian assumption for the blood as well as modelling the arterial wall as linearly elastic lead to significant differences in oscillatory hemodynamic properties with respect to the use of Carreau fluid together with hyperelastic vessel model, even in large vessel aneurysms. Show more

Keywords: Pulsatile hemodynamics, fluid-solid interaction (FSI), abdominal aortic aneurysm (AAA), blood rheology, blood vessel modeling, oscillatory shear index (OSI)

DOI: 10.3233/BIR-180202

Citation: Biorheology, vol. 56, no. 1, pp. 51-71, 2019