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。这将使肾移植每年增加20%。为了利用这些肾脏，需要针对WI肾脏的新的保存方法。在这项研究中，我们将开发保护WI肾的方法。我们将使用一个供体模型（脑死亡狗）来模拟临床情况。特异性目的1将确定脑死亡（BD）与移植生存能力之间的关系，包括BD时间、保存方法和保存时间等变量。特异性目的2将确定在肾移植模型中，BD和WI是否比WI本身对肾脏造成更大的损伤。这些研究将明确定义完成本研究所需的模型。特异性目的3将定义BD、WI和保存损伤对肾血管（内皮细胞和平滑肌细胞）和实质细胞代谢的机制。我们的假设是，BD和WI结合冷保存2导致内皮细胞和实质细胞的钙依赖性细胞代谢中断，导致活性氧代谢物（ROM）生成增加，细胞骨架变化导致细胞活力丧失。我们将在体外使用血管和实质细胞模型验证这一假设。我们将研究改变钙代谢、ROM生成和细胞骨架变化的药物如何影响暴露于BD、WI和保存的肾脏血管和实质细胞的活力和功能。我们认为，持续的低温机器灌注肾脏可以逆转BD和WI引起的不可逆损伤的一些后果，比简单的冷藏更好。在Specific Aim 4中，我们将使用肾脏移植模型来开发一种改进的方法来保存WI后BD供者的肾脏。我们的方法将基于Specific Aim 3中开发的灌注修饰，该修饰在我们的体外模型中被证明可以改善肾脏的保存。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，也适用于低血压或老年供者的肾脏。这将增加可用于移植的肾脏数量，并减少健康和不理想供体肾脏移植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.