ORGAN PRESERVATION FOR TRANSPLANTATION

肾脏的短缺限制了有效的国家肾移植计划。 一种解决方案是使用现在不适合移植的肾脏，即供体中暴露于热缺血（WI）的肾脏。 这可能会使肾移植每年增加20%。 为了利用这些肾脏，需要专门针对WI肾脏的新的保存方法。 在这项研究中，我们将开发的方法来保存WI肾。 我们将使用供体模型（脑死亡犬）来模拟临床情况。 具体目标1将确定脑死亡（BD）和移植存活率之间的关系，包括BD时间，保存方法和保存时间等变量。 具体目标2将确定在肾移植模型中，BD和WI对肾脏的损伤是否大于WI本身。 这些研究将明确界定完成这项研究所需的模式。 具体目标3将明确BD、WI和保存损伤对肾血管（内皮和平滑肌细胞）和实质细胞代谢的机制。 我们的假设是，BD和WI，与冷保存2相结合，导致内皮细胞和实质细胞的细胞代谢的钙依赖性破坏，导致活性氧代谢产物（ROM）的产生增加，细胞骨架的变化，导致细胞活力的丧失。 我们将使用血管和实质细胞模型在体外测试这一假设。 我们将研究如何代理修改钙代谢，ROM的产生，和细胞骨架的变化影响的活力和功能的血管和实质细胞从肾脏暴露于BD，WI和保存。 我们认为，对肾脏进行持续低温机器灌注将扭转BD和WI造成不可逆转损伤的一些后果，比简单的冷藏更好。 在具体目标4中，我们将使用肾移植模型来开发一种改进的方法，以在WI后保存BD供体的肾脏。 我们的方法将基于特定目标3中开发的灌注液修改，这些修改显示出在我们的体外模型中改善了肾脏的保存。 我们的目标是开发一种新的肾脏保存方法，不仅适用于WI肾脏，而且适用于肥胖或老年供体的肾脏。 这将增加可用于移植的肾脏数量，并减少健康和不太理想的供体肾脏中移植肾功能延迟和原发性无功能的发生率。

The shortage of kidneys is limitation for an effective national renal transplant program. One solution is to use kidneys not now suitable for transplantation, i.e. those exposed to warm ischemia (WI) in the donor. This could increase renal transplants by 20 percent/year. To utilize these kidneys requires new preservation methods specific for WI kidneys. In this study we will develop methods to preserve the WI kidney. We will use a donor model (brain dead dog) to mimic the clinical situation. Specific Aim 1 will determine the relationship between brain death (BD) and transplant viability, including variables such as time of BD, preservation method, and length of preservation. Specific Aim 2 will determine if, in a renal transplant model, BD and WI cause greater injury to the kidney than WI by itself. These studies will define clearly the model necessary for the completion of this study. Specific Aim 3 will define the mechanisms of BD, WI, and preservation injury on the renal vascular (endothelial and smooth muscle cells) and parenchymal cell metabolism. Our hypothesis is that BD and WI, combined with cold preservation 2causes a Ca-dependent disruption of cell metabolism in both endothelial and parenchymal cells leading to increased reactive oxygen metabolite (ROM) generation, and cytoskeletal changes leading to loss of cell viability. We will test this hypothesis in vitro using vascular and parenchymal cell models. We will study how agents that modify Ca metabolism, ROM generation, and cytoskeleton changes affect viability and functions of vascular and parenchymal cells from kidneys exposed to BD, WI, and preservation. We propose that continuous hypothermic machine perfusion of kidneys will reverse some of the consequences of BD and WI that cause irreversible injury, better than simple cold storage. In Specific Aim 4, we will use the renal transplant model to develop an improved method to preserve the kidney from the BD donor after WI. Our method will be based upon perfusate modifications developed in Specific Aim 3 that are shown to improve preservation of the kidney in our in vitro models. Our goal will be to develop a new method of renal preservation, appropriate for not only the WI kidney, but also kidneys from hypotensive or older donors. This will increase the number of kidneys available for transplantation, and reduce the incidence of delayed graft function and primary nonfunction in both healthy and less-than-ideal donor kidneys.