NEW APPROACH TO ENDOTHELIAL CLEFT STRUCTURE

我们提出了一个新的假说来解释单独灌流中溶质和水交换的调节。 剪切应力作用于血管内皮细胞的微血管 薄膜。总体假设是内皮细胞的三维有序属性 使其能够作为血浆蛋白的初级分子筛的糖基化催化剂也决定了它的 作为剪应力传感器，调节内皮屏障的通透性。目标1是测量这两个小的 单独灌流微血管施加剪切时的溶质和大溶质渗透系数 应力是不同的，而糖萼的结构保持不变。跨血管水流量和有效率 将测量血浆蛋白的渗透压。具体的假设是，一个完整的糖萼 作为机械换能器和主分子筛，会增加小的溶质渗透率 对大分子的渗透性和选择性没有变化。在目标2中，糖萼的结构是 对其进行修改以减少其作为分子筛的作用，并允许剪切应力施加在更接近 内皮表面。具体的假设是，完整的糖萼通常保护切变感觉。 内皮细胞膜上调节水和ALL共同途径的机械换能器 溶质。目标3是在有和没有完整血管的情况下，以非常低的切变率长期灌流微血管。 糖萼。具体的假设是，需要持续的剪应力来维持内皮细胞。 剪切力急剧变化引起小溶质渗透性快速调节的表型， 水不变，溶质渗透率大。将指导实验设计和解释 根据我们目前的水和溶质通过糖萼和内皮间裂隙的运输模型，以及通过一个 从糖萼到皮质细胞骨架的力传递的新模型。合并后的 微灌注、生物物理、超微结构和建模方法将提供对 剪切力对正常微血管通透性的调节可能导致改善营养的策略 交付和增强受伤或手术后的组织恢复。我们的实验评估了常见的 调节水、溶质、白细胞和红细胞的内皮糖催化剂的机械性能 血管内皮细胞表面的通量。

We propose a new hypothesis to explain the regulation of solute and water exchange in individually perfused mammalian microvessels by shear stress applied to the endothelial cell glycocalyx and at the endothelial cell membrane. The overall hypothesis is that the three-dimensional ordered properties of the endothelial glycocalyx which enable it to function as the primary molecular sieve for plasma proteins also determine its function as a shear stress sensor to regulate endothelial barrier permeability. Aim 1 is to measure both small solute and large solute permeability coefficients in individually perfused microvessels when applied shear stress is varied, and the structure of the glycocalyx is maintained. Transvascular water flux and effective osmotic pressures of plasma proteins will be measured. The specific hypothesis is that an intact glycocalyx acting as a mechanotransducer and the principal molecular sieve will increase small solute permeability with no change in the permeability and selectivity to large molecules. In Aim 2 the structure of the glycocalyx is modified to reduce its action as a molecular sieve and to allow shear stress to be applied closer to the endothelial surface. The specific hypothesis is that the intact glycocalyx normally protects shear-sensing mechanotransducers at the endothelial cell membrane that regulate a common pathway for water and all solutes. Aim 3 is to perfuse microvessels for long periods at very low shear with and without an intact glycocalyx. The specific hypothesis is that continuous shear stress is required to maintain an endothelial phenotype in which an acute change in shear stress causes rapid regulation of small solute permeability, with no change in water and large solute permeability. Experimental design and interpretation will be guided by our current model of water and solute transport through the glycocalyx and inter-endothelial cleft and by a new model of force transduction from the glycocalyx to the cortical cytoskeleton. The combined microperfusion, biophysical, ultrastructural, and modeling approaches will provide new understanding of the permeability regulation by shear stress in normal microvessels and may lead to strategies to improve nutrient delivery and enhance tissue recovery after injury or surgery. Our experiments evaluate the common mechanical properties of the endothelial glycocalyx that modulate water, solute, leukocyte, and red cell fluxes at the endothelial cell surface.