Biophysical Modeling of Solute Transport in Human IVD

描述（由申请人提供）：腰痛是这个国家主要的社会经济问题。虽然腰痛的确切原因尚不清楚，但椎间盘退行性改变（IVD）已被认为是可能的主要病因。营养供应不足被认为是椎间盘退变的机制之一。由于材料的独特组成和结构以及IVD组织中机械-电化学耦合现象的复杂性，对人体IVD的运输特性缺乏了解，也缺乏系统研究IVD中营养物质运输的合适理论模型。本申请的目的是确定人体ivd的输运特性和这些特性的本构模型，以便在随后的拨款申请中开发新的机械-电化学输运理论和有限元模型。该项目的长远目标是：(1)阐明椎间盘退变的病因，(2)帮助制定恢复组织功能或延缓进一步椎间盘退变的策略，以及(3)开发新的、微创的椎间盘退变诊断工具。在本研究中，我们将确定人体腰椎IVD组织的机械、物理化学和运输特性（Specific Aims #1-#5），并开发和验证运输特性的新本构模型（Specific Aims #6 & #7）。基于机械电化学原理的新技术将用于测试IVD组织的传输特性，包括应变依赖的水力渗透性，应变依赖的固定电荷密度，应变依赖的电导率，以及人体腰椎间盘中离子和营养物质（氧和葡萄糖）的应变依赖的扩散率。这些特性将与组织的组成有关，并将用于发展新的组织结构理论，以研究人体静脉血管的营养供应。材料特性和技术方面的理论、知识和技术的进步将对椎间盘退变的病因以及其他研究领域（如生物组织中的药物输送）产生重大影响。还包括分享和传播本研究中开发的理论、技术和数据的计划。

DESCRIPTION (provided by applicant): Low back pain is a major socio-economic concern in this country. Although the exact cause for low back pain is unclear, the degenerative changes of the intervertebral disc (IVD) have been implicated as a possible primary etiologic factor. Poor nutritional supply is believed to be one of the mechanisms for disc degeneration. Due to the unique composition and structure of the materials and the complexity of the mechano-electrochemical coupling phenomena in IVD tissues, there is a lack of knowledge on transport properties of human IVDs or appropriate theoretical models for investigating nutrient transport in IVD systematically. The purpose of this application is to determine the transport properties and the constitutive models for these properties in human IVDs required for the development of a new mechano-electrochemical transport theory and finite element model in a subsequent grant application. The broad, long-term objectives of this project are to (1) elucidate the etiology of disc degeneration, (2) help develop strategies for restoring tissue function or retarding further disc degeneration, and (3) develop novel, less-invasive diagnostic tools for disc degeneration. In this research, we will determine the mechanical, physicochemical, and transport properties of human lumbar IVD tissues (Specific Aims #1-#5) and develop and validate new constitutive models for transport properties (Specific Aims #6 & #7). New technologies, based on mechano-electrochemical principles, will be developed for testing transport properties of IVD tissues, including strain-dependent hydraulic permeability, strain-dependent fixed charge density, strain-dependent electrical conductivity, and strain-dependent diffusivity of ions and nutrients (oxygen and glucose) in human lumbar discs. These properties will be correlated to the composition of the tissue, and will be used in developing the new constitutive theories in the research of nutritional supply in human IVDs. The advance in theory, knowledge on material properties, and techniques will have a significant impact on understanding the etiology of disc degeneration as well as on other areas of research, such as drug delivery in biological tissues. A plan for sharing and disseminating the theory, techniques, and data developed in this research is also included.