The role of carbamylation in uremia associated heart disease

描述（由申请人提供）：候选人：我是一名医生，科学家寻求发现诊断解决方案的问题，糖尿病和肾脏疾病。我完成了博士学位。研究脂联素在肝脏胰岛素敏感性中的作用。我对糖尿病诊断挑战的兴趣使我成为临床病理学的住院医师，以获得临床检测开发方面的专业知识。我开发了血清脂联素、生物可利用的25-羟基维生素D和血清氨甲酰化白蛋白（%C-Alb）的测定方法，该方法类似于“尿毒症血红蛋白A1 c”，其值与血尿素相关，可预测透析患者的死亡率。 我是贝斯以色列女执事医学中心病理学系的助理医学主任，也是哈佛医学院的病理学讲师;我的大部分时间都用于研究。我的临床地位是独一无二的 与我的研究目标相一致。我的短期目标是通过K 08项目进行密集的研究培训，利用这段时间完成我的分析项目，获得动物模型实验和临床研究课程的经验，并获得足够的初步数据，以支持申请独立研究奖。我的长期目标是继续在检测开发方面的转化研究，重点是了解尿毒症的病理生理学，并解决肾脏疾病和糖尿病的诊断，预防和管理的挑战。我的长期职业目标将需要额外的临床研究培训，以使我成为一个有效的翻译研究者。我与Ananth Karumanchi和Ravi Thadhani博士建立了指导关系，他们是先兆子痫和肾脏疾病领域的两位杰出高级研究人员。环境：我与BIMDC和哈佛医学院的关系使我处于一个首屈一指的研究环境中。我的部门为我提供了独立的实验室空间和质谱仪仪器，用于执行我的项目的测定开发和性能，我的临床和研究实验室位于波士顿朗伍德医疗区内的BIDMC主要医院综合体。朗伍德也是哈佛公共卫生学院的所在地，我将在那里接受人体研究和生物统计学方面的培训。在我可用的资源中包括来自哈佛CTSC的支持。如果我获得K 08支持，我将有资格参加临床研究 通过哈佛公共卫生学院的临床有效性暑期项目进行研究课程，并攻读公共卫生硕士学位。我的系主任杰弗里·萨菲茨（Jeffrey Saffitz）竭尽全力为年轻的研究人员提供一个培养研究环境。研究：尿素衍生的氰酸盐引起的蛋白质氨甲酰化可能导致慢性和终末期肾病（ESRD）的并发症。我们假设蛋白质氨甲酰化是由时间平均尿素浓度和氰酸清除剂如游离氨基酸之间的平衡决定的。在这里，我们报告发现一个特定的氨甲酰化位点的人白蛋白和方法来测量氨甲酰化白蛋白（%C-Alb），使用液相色谱和串联质谱。当我们分析患者样本中的%C-Alb时，我们发现与存活者相比，在血液透析第一年期间死亡的ESRD患者的%C-Alb升高，并且升高的%C-Alb水平与全因死亡率显著相关（风险比3.76，P=0.0002）。虽然%C-Alb水平与平均血尿素浓度正相关，正如预期的那样，我们发现%C-Alb和许多血清氨基酸浓度之间同样强烈的负相关性。这些结果表明，血液透析患者的氨基酸缺乏可能有助于蛋白质氨甲酰化，氨基酸补充剂可用于治疗血液透析患者，以抑制蛋白质氨甲酰化及其后遗症。以前的动物模型研究表明，尿素直接导致动脉粥样硬化和尿毒症心肌病，但尚不清楚这是否是由于氨甲酰化。以前的研究也表明，氨甲酰化抑制巯基抗氧化剂的作用。氧化应激增加与慢性肾脏疾病、动脉粥样硬化和尿毒症性心肌病有关，但氨甲酰化是否是尿毒症相关氧化应激及其心血管病理学的重要因素尚不清楚。我们最近将这些结果发表在《Science Trans. Med.》和《CJEAN》杂志上，我们目前正在通过一项试验性临床试验对这些研究进行跟踪，该试验旨在测试氨基酸氨甲酰化清除剂对血液透析患者蛋白质氨甲酰化的影响。在这个建议中，我们试图进一步了解尿素对心脏的影响，并测试各种特定的治疗“超氨甲酰化。“具体目标1将使用肾衰竭和动脉粥样硬化形成的小鼠模型来测试氨甲酰化是否直接导致动脉粥样硬化。具体目标2将使用肾衰竭大鼠模型测试氨甲酰化是否直接导致心肌纤维化、肥大和重塑，以及尿素是否激活心肌细胞氧化应激信号通路。具体目标3将测试氨基酸补充剂或其他氨甲酰化清除剂是否可以减少氨甲酰化和改善尿毒症相关的心脏病。具体目标4将测试硫醇抗氧化剂α-硫辛酸是否可以减少氨甲酰化和氧化应激，并改善尿毒症相关的心脏病。

DESCRIPTION (provided by applicant): Candidate: I am a physician-scientist seeking to discover diagnostic solutions to the problems of diabetes mellitus and kidney disease. I completed a Ph. D. working on the role of adiponectin in hepatic insulin sensitivity. My interest i the diagnostic challenges of diabetes mellitus led me to a residency in clinical pathology to gain expertise in clinical assay development. I have developed assays for serum adiponectin, bioavailable 25-hydroxyvitamin D, and serum carbamylated albumin (%C-Alb) that is akin to "hemoglobin A1c for uremia," whose values are correlated to blood urea and are predictive of mortality in patients on dialysis. I am the Assistant Medical Director in the Department of Pathology at Beth Israel Deaconess Medical Center and an Instructor of Pathology at Harvard Medical School; the majority of my time is protected for research. My clinical position is uniquely synergistic with my research goals. My short term goals are to pursue an intensive period of research training through the K08 program, use this time to complete my assay project, gain experience in animal model experiments and coursework in clinical investigation, and obtain sufficient preliminary data to support application for an independent research award. My long-term goals are to continue translational research in assay development, focusing on understanding the pathophysiology of uremia, and addressing the challenges of diagnosis, prevention, and management of kidney disease and diabetes mellitus. My long-term career goals will require additional training in clinical investigation in order for me to become an effective translational investigator. I have established mentoring relationships with Drs. Ananth Karumanchi and Ravi Thadhani, two prominent senior investigators in the fields of preeclampsia and kidney disease. Environment: My affiliations with BIMDC and Harvard Medical School place me within a research environment that is second to none. My department has provided me with independent laboratory space and mass spectrometer instrumentation for the execution of assay development and performance for my project, my clinical and research laboratories are located in the BIDMC main hospital complex within the Longwood Medical Area of Boston. Longwood is also home to the Harvard School of Public Health where I will pursue training in human subjects research and biostatistics. Among the resources available to me include support from the Harvard CTSC. If I am granted K08 support I will be eligible to enroll in clinical research coursework through the Harvard School of Public Health's Summer Program in Clinical Effectiveness and pursue an MPH degree. My departmental chair Jeffrey Saffitz has gone to great lengths to provide a nurturing research environment for young investigators. Research: Protein carbamylation by urea-derived cyanate may contribute to the complications of chronic and end stage kidney disease (ESRD). We hypothesized that protein carbamylation is determined by the balance between time-averaged urea concentrations and cyanate scavengers such as free amino acids. Here, we report discovery of a specific carbamylation site in human albumin and methods to measure carbamylated albumin (%C-Alb) using liquid chromatography and tandem mass spectrometry. When we analyzed %C-Alb in patient samples we found that %C-Alb was elevated in ESRD patients who died during the first year of hemodialysis compared to survivors, and elevated %C-Alb levels were significantly associated with all-cause mortality (hazard ratio 3.76, P=0.0002). Although %C-Alb levels were positively correlated to average blood urea concentrations as expected, we found equally strong negative correlations between %C-Alb and concentrations of many serum amino acids. These results suggested that amino acid deficiencies in hemodialysis patients may contribute to protein carbamylation, and that amino acid supplements could be used in the treatment of hemodialysis patients in order to inhibit protein carbamylation and its sequelae. Previous animal model studies have shown that urea contributes directly to atherosclerosis and uremic cardiomyopathy, but it is unknown whether this is due to carbamylation. Previous studies have also shown that carbamylation inhibits the actions of thiol antioxidants. Increased oxidative stress has been linked to chronic kidney disease, atherosclerosis, and uremic cardiomyopathy, but it is unknown whether carbamylation is a significant contributor to uremia-associated oxidative stress and its cardiovascular pathology. We recently published these results in the journals Science Trans. Med. And CJASN, and we are currently following up on these studies through a pilot clinical trial testing the effects of amino acid carbamylation scavengers on protei carbamylation in hemodialysis patients. In this proposal we seek to further our understanding of the effects of urea on the heart, and test various specific treatments for "hypercarbamylation." Specific Aim 1 will test whether carbamylation directly contributes to atherosclerosis using a mouse model of kidney failure and atherogenesis. Specific Aim 2 will test whether carbamylation directly contributes to myocardial fibrosis, hypertrophy, and remodeling using a rat model of kidney failure, and whether urea activates cardiomyocyte oxidative stress signaling pathways. Specific Aim 3 will test whether amino acid supplements or other carbamylation scavengers can reduce carbamylation and ameliorate uremia-associated heart disease. Specific Aim 4 will test whether a thiol antioxidant, alpha lipoic acid, can reduce carbamylation and oxidative stress, and ameliorate uremia-associated heart disease.