Understanding the multiscale basis of solute transport in the cartilage endplate

了解软骨终板中溶质转运的多尺度基础

• 批准号: 10701756
• 负责人: Jae-Young Jung
• 金额: $ 7.61万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10701756
• 关键词: 3-Dimensional; Advanced Glycosylation End Products; Affect; Age; Aging; Anisotropy; Area; Biochemical; Biochemistry; Biological Assay; Biological Response Modifier Therapy; Cadaver; Cartilage; Cells; Characteristics; Charge; Chronic low back pain; Clinical; Collagen; Collagen Fibril; Data; Data Set; Deposition; Disease; Electron Microscopy; Equilibrium; Face; Freezing; Genes; Grant; Growth Factor; Guidelines; Harvest; Human; Hydration status; Impairment; In Vitro; Incubated; Investigation; Ions; Knowledge; Length; Link; Low Back Pain; Measurement; Measures; Medical; Minerals; Modeling; Modification; Musculoskeletal; Nanoporous; Nature; Nutrient; Operative Surgical Procedures; Outcome; Penetration; Permeability; Play; Porosity; Property; Proteoglycan; Research; Role; Sampling; Scanning Electron Microscopy; Series; Structure; Swelling; Testing; Thick; Tissues; Training; Transmission Electron Microscopy; Variant; Water; Work; aggrecan; crosslink; disability; disc regeneration; driving force; experimental study; glucose uptake; intervertebral disk degeneration; microscopic imaging; millimeter; nano; nanometer; nanoscale; novel; nucleus pulposus; nutrition; patient response; preservation; pressure; soft tissue; solute; treatment response; uptake

PROJECT ABSTRACT Low back pain is the leading cause of disability and linked to disc degeneration. Existing treatments for disc degeneration are surgical in nature, and thus, there is an unmet need for non-surgical alternatives. Intradiscal therapy looks promising but it requires high nutrition supply. Nutrients and metabolites entering and exiting the nucleus pulposus must penetrate the cartilage endplate (CEP) and its permeability depends on matrix biochemical composition (matrix quantity) and structure, for example, increased deposition of mineral, proteoglycans, or collagen limits the physical pore space available for solutes to pass, while a dense and damaged CEP matrix from degenerated discs might impair nutrient transport than an intact CEP. Indeed, a prior study from our lab showed that higher AGE content in the CEP associates with lower solute uptake for a given amount of matrix. Despite a general understanding of how matrix quantity and quality impact bulk CEP transport properties, knowledge about transport in relation to the multiscale organization of the CEP matrix constituents is lacking. These gaps motivate my main hypotheses that 1) higher glucose uptake is positively correlated with structural characteristics across multiple length scales, including greater pore network connectivity and a higher degree of matrix organization, and 2) low CEP transport properties correlate with higher AGEs, independent of matrix quantity. These hypotheses will be tested through the following two aims. In Aim 1, I will discover the structural organization of the CEP matrix across millimeter to nanometer, and how these hierarchical structure affects solute transport properties. A total of 126 samples of human CEP tissue (from 15 cadavers) will be harvested and then ordered as three groups by the rank of nutrient transport (high, middle, and low uptake). Then, these will be related to biochemical compositions, tissue hydration, and bulk material properties (porosity and thickness). Local material properties (micro- and nano- porosity and pore size/distribution) will be measured and compared with the other quanfiable data, such as pore connectivity, pore size distribution, and collagen/matrix anisotropy. A series of 2D dataset will be obtained, segmented, and reconstructed to quantify pore area/volume and in 3D. These structural outcomes will be related to biochemical composition, hydration, and porosity. In Aim 2, I will identify nanostructural and biochemical changes altered by the effect of in-vitro ribosylation assay. Previous studies showed that negatively charged sGAG attracts water, while increased levels of AGEs negatively correlated to tissue hydration. I will develop an in-vitro ribosylation assay and a glucose uptake assay to measure the variation AGE contents (control vs. incubated) of the CEP samples. Lastly, the obtained data will be related to the changes of matrix charge distribution, nanoporosity, and collagen D-period spacing. These studies will clarify and characterize the effect of hierarchical structure and matrix quality modification of CEP tissue on solute transport.

项目摘要 腰痛是残疾的主要原因，并与椎间盘变性有关。现有的治疗方法 椎间盘衰减本质上是手术性的，因此，对非手术替代方案有未满足的需求。 验证疗法看起来很有希望，但需要高营养供应。营养和代谢物进入和 退出原子核必须穿透软骨端板（CEP），其渗透性取决于基质 生化组成（基质数量）和结构，例如，矿物的沉积增加， 蛋白聚糖或胶原蛋白限制可用于溶质的物理孔隙空间，而密集和密集 与完整的CEP相比，退化的圆盘受损的CEP基质可能会损害营养转运。确实，先验 我们实验室的研究表明，在给定 矩阵的量。尽管对矩阵数量和质量如何影响大量CEP运输有一般了解 属性，有关CEP矩阵成分多尺度组织的运输知识是 缺乏。这些差距激发了我的主要假设，即1）较高的葡萄糖吸收与 多个长度尺度之间的结构特性，包括更大的孔网连接和更高的 矩阵组织的程度和2）低CEP传输特性与较高的年龄相关，独立于 矩阵数量。这些假设将通过以下两个目标进行检验。在AIM 1中，我会发现 CEP基质的结构组织跨毫米至纳米，以及这些等级结构如何 影响溶质传输特性。总共126个人类CEP组织（来自15个尸体）将是 通过养分运输（高，中和低吸收）的等级收获，然后以三组订购。 然后，这些将与生化成分，组织水合和块状材料特性有关（孔隙率 和厚度）。将测量局部材料特性（微观和纳米孔隙度以及孔径/分布） 并与其他可量化数据（例如孔连接性，孔径分布和）相比 胶原蛋白/基质各向异性。将获得一系列2D数据集，进行分割和重建以量化 孔区/体积和3D。这些结构结果将与生化成分，水合， 和孔隙率。在AIM 2中，我将确定因体外影响而改变的纳米结构和生化变化 核糖基化测定。先前的研究表明，带负电荷的SGAG吸引水，而水平增加 与组织水合有负相关的年龄。我将开发一个体外核糖基化测定法和葡萄糖 测量CEP样品的变异年龄含量（对照与孵育）的摄取测定。最后， 获得的数据将与矩阵电荷分布，纳米孔和胶原蛋白D-Period的变化有关 间距。这些研究将阐明和表征层次结构和基质质量的影响 在溶质转运上修饰CEP组织。