Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels.
Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels.
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DOI：
10.3233/ch-151924
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发表时间：
2015
影响因子：
2.1
通讯作者：
Hawkins K
中科院分区：
文献类型：
--
作者：
Badiei N;Sowedan AM;Curtis DJ;Brown MR;Lawrence MJ;Campbell AI;Sabra A;Evans PA;Weisel JW;Chernysh IN;Nagaswami C;Williams PR;Hawkins K
采用可控应力平行叠加（CSPS）和小振幅振荡剪切（SAOS）流变技术研究了全血和纤维蛋白凝胶的初始凝块形成。单向剪切应力对初始凝块的微观结构，形成动力学和弹性的影响报告的纤维蛋白网络的分形维数（df），凝胶网络形成时间（TGP）和剪切弹性模量，分别。CSPS的这第一个血液流变学应用的结果揭示了早期凝块微观结构对生理学相关水平的剪切应力的显著敏感性，这些是一个数量级低于先前由SAOS研究的。CSPS试验显示，将形成的凝块暴露于增加水平的剪切应力会产生相应的df升高，这与单向流动下更紧密、更紧凑的凝块微观结构的形成一致。记录到剪切弹性的相应增加。纤维蛋白凝块和全血的剪切弹性和DF之间建立的比例关系证实了纤维蛋白网络的主要微观结构组成部分的早期凝块在其施加的应力的响应。通过流变仪和显微镜对纤维蛋白凝块形成的补充研究揭示了增加DF所需的大量额外网络质量，并提供证据支持单向剪切下血液凝块的微观结构变化可能归因于流动增强凝血酶生成和活化的假设。CSPS还确定了单向剪切应力的阈值，高于该阈值时，无法检测到早期凝块形成。CSPS被证明是一个有价值的血液流变学工具的生理和病理水平的剪切凝块性能的影响的研究。
Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (df) of the fibrin network, the gel network formation time (TGP) and the shear elastic modulus, respectively. The results of this first haemorheological application of CSPS reveal the marked sensitivity of incipient clot microstructure to physiologically relevant levels of shear stress, these being an order of magnitude lower than have previously been studied by SAOS. CSPS tests revealed that exposure of forming clots to increasing levels of shear stress produces a corresponding elevation in df, consistent with the formation of tighter, more compact clot microstructures under unidirectional flow. A corresponding increase in shear elasticity was recorded. The scaling relationship established between shear elasticity and df for fibrin clots and whole blood confirms the fibrin network as the dominant microstructural component of the incipient clot in terms of its response to imposed stress. Supplementary studies of fibrin clot formation by rheometry and microscopy revealed the substantial additional network mass required to increase df and provide evidence to support the hypothesis that microstructural changes in blood clotted under unidirectional shear may be attributed to flow enhanced thrombin generation and activation. CSPS also identified a threshold value of unidirectional shear stress above which no incipient clot formation could be detected. CSPS was shown to be a valuable haemorheological tool for the study of the effects of physiological and pathological levels of shear on clot properties.