NEW APPROACH TO ENDOTHELIAL CLEFT STRUCTURE

内皮裂隙结构的新方法

• 批准号: 3363272
• 负责人: FITZ-ROY E CURRY
• 金额: $ 28.79万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-05-01 至 1994-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3363272
• 关键词: Anura; body water; capillary; extracellular matrix; freeze etching; immunocytochemistry; mathematical model; membrane structure; model design /development; pore forming protein; protein structure function; solute; vascular endothelium permeability

The overall aim of our research is to develop a combined engineering, ultrastructural and biophysical approach to the mechanisms whereby endothelial cells and the clefts between the cells modulate microvessel permeability. Freeze fracture studies and ultrathin serial sections have demonstrated that endothelial cells are joined by an array of junctional strands which are interrupted at intervals allowing passage of water and solutes. Cytochemical and permeability studies also indicate that all or part of the cleft may be filled with a fibrous matrix. We describe novel experiments guided by a new conceptual theoretical framework to relate permeability properties of segments of individually perfused microvessels, having known permeability properties, to the ultrastructure of the junctional strands between adjacent endothelial cells and a fiber matrix within the cleft. The specific aims of the proposal are 1) to evaluate the proposal that the permeability properties of microvessel walls to water and small solutes are determined by the frequency of small discontinuities in the junctional strand; and 2) to evaluate the relative contribution of structures associated with the junctional strand and the fiber matrix to the molecular filter at the microvessel wall. The primary focus of our new approach is the analysis of the three-dimensional convective-diffusive spread of tracer molecules on the albuminal side of the interruptions in the junction strand arrays. This spread is analogous to the growth of a wake on the downstream side of a small object at very low Reynolds numbers. Preliminary results from serial sections by Dr. Adamson indicate that this approach is necessary to investigate the geometry and distribution of hypothetical small pores or slits in the junction strands which cannot be resolved by conventional 30-40nm sections. The combined theoretical and experimental approach adopted herein takes advantage of a recently developed highly accurate analytic solution by Dr. Weinbaum for the three-dimensional viscous flow in a cleft, which contains junction strands with discrete pores and slender cross-bridging fiber components. The model is needed to interpret the three-dimensional distribution of tracer in the wake experiments proposed in Specific Aim 1, and to analyze the results of the experiments with larger solute molecules proposed in Specific Aim 2. In both experimental designs measurements will be performed on individual perfused microvessels of precisely known permeability properties using techniques that have been extensively developed in Dr. Curry's laboratory. We believe this combined theoretical and experimental approach goes far beyond past and current attempts to delineate the junction and fiber matrix structures which modulate microvessel permeability. These studies are the most direct approach to a new understanding of the nature of the resistances which determine microvessel permeability in normal tissue and during recovery from injury.

我们研究的总体目标是开发一种组合工程， 超微结构和生物物理方法的机制 内皮细胞和细胞之间的缝隙调节微血管 渗透性。 冷冻断裂研究和超薄连续切片 证明内皮细胞通过一系列连接 每隔一段时间打断的股线允许水通过和 溶质。 细胞化学和渗透性研究还表明，所有或 部分裂隙可能被纤维基质填充。 我们描述小说 以新的概念理论框架为指导的实验将 单独灌注的微血管节段的渗透性特性， 具有已知的渗透特性，对超微结构 相邻内皮细胞和纤维基质之间的连接链 裂缝之内。 该提案的具体目标是 1) 评估 建议微血管壁对水的渗透特性和 小溶质由小不连续性的频率决定 连接链； 2）评估相对贡献 与连接股和纤维基质相关的结构 微血管壁上的分子过滤器。 我们新的主要关注点 方法是三维对流-扩散分析 示踪分子在中断的白蛋白侧的扩散 连接链阵列。 这种传播类似于 在雷诺数非常低的小物体的下游侧唤醒。 Adamson 博士的系列切片的初步结果表明， 方法对于研究几何形状和分布是必要的 假设的小孔或缝隙在连接线中，不能被 通过传统的 30-40nm 切片可以解决。 综合理论和 本文采用的实验方法利用了最近的 Weinbaum 博士针对以下问题开发了高精度分析解决方案 裂缝中的三维粘性流，其中包含连接链 具有离散的孔隙和细长的交叉桥接纤维成分。 型号 需要解释示踪剂的三维分布 具体目标 1 中提出的尾流实验，并分析结果 具体目标 2 中提出的使用较大溶质分子的实验。 在这两种实验设计中，测量都将在个体上进行 使用精确已知渗透特性的灌注微血管 库里博士实验室已广泛开发的技术。 我们相信这种理论和实验相结合的方法会走得很远 超越过去和当前描绘连接处和纤维矩阵的尝试 调节微血管通透性的结构。 这些研究是 对事物本质有新认识的最直接方法 决定正常组织中微血管通透性的阻力 受伤恢复期间。