Bloksgaard Maria, Thorsted Bjarne, Brewer Jonathan R, De Mey Jo G R
Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark;
Department of Biochemistry and Molecular Biology, University of Southern Denmark.
J Vis Exp. 2018 Apr 9(134):57451. doi: 10.3791/57451.
The pathogenic contribution of resistance artery remodeling is documented in essential hypertension, diabetes and the metabolic syndrome. Investigations and development of microstructurally motivated mathematical models for understanding the mechanical properties of human resistance arteries in health and disease have the potential to aid understanding how disease and medical treatments affect the human microcirculation. To develop these mathematical models, it is essential to decipher the relationship between the mechanical and microarchitectural properties of the microvascular wall. In this work, we describe an ex vivo method for passive mechanical testing and simultaneous label-free three-dimensional imaging of the microarchitecture of elastin and collagen in the arterial wall of isolated human resistance arteries. The imaging protocol can be applied to resistance arteries of any species of interest. Image analyses are described for quantifying i) pressure-induced changes in internal elastic lamina branching angles and adventitial collagen straightness using Fiji and ii) collagen and elastin volume densities determined using Ilastik software. Preferably all mechanical and imaging measurements are performed on live, perfused arteries, however, an alternative approach using standard video-microscopy pressure myography in combination with post-fixation imaging of re-pressurized vessels is discussed. This alternative method provides users with different options for analysis approaches. The inclusion of the mechanical and imaging data in mathematical models of the arterial wall mechanics is discussed, and future development and additions to the protocol are proposed.
阻力动脉重塑的致病作用在原发性高血压、糖尿病和代谢综合征中已有记载。研究并开发基于微观结构的数学模型，以了解健康和疾病状态下人体阻力动脉的力学特性，这有助于理解疾病和医学治疗如何影响人体微循环。为了开发这些数学模型，必须破译微血管壁力学特性与微观结构特性之间的关系。在这项工作中，我们描述了一种用于离体被动力学测试以及同时对分离的人体阻力动脉壁中的弹性蛋白和胶原蛋白微观结构进行无标记三维成像的方法。该成像方案可应用于任何感兴趣物种的阻力动脉。描述了图像分析方法，用于量化：i）使用Fiji软件测量压力引起的内弹性膜分支角度和外膜胶原直线度的变化；ii）使用Ilastik软件确定胶原蛋白和弹性蛋白的体积密度。最好所有力学和成像测量都在有活性、灌注的动脉上进行，不过，也讨论了一种替代方法，即使用标准视频显微镜压力肌动描记法结合重新加压血管的固定后成像。这种替代方法为用户提供了不同的分析方法选择。讨论了将力学和成像数据纳入动脉壁力学数学模型的问题，并提出了该方案未来的发展方向和补充内容。
