The role of carbamylation in uremia associated heart disease

求职者：我是一名内科科学家，致力于寻找糖尿病和肾脏疾病的诊断解决方案。我完成了一个博士学位，研究脂联素在肝脏胰岛素敏感性中的作用。我对糖尿病的诊断挑战的兴趣使我成为临床病理学的住院医师，以获得临床分析开发方面的专业知识。我已经开发了血清脂联素、生物可利用的25-羟基维生素D和血清氨基甲酸白蛋白(%C-Alb)的分析方法，它们的值与血尿素相关，可以预测透析患者的死亡率。我是贝丝以色列女执事医学中心病理部的助理医务主任，也是哈佛医学院的病理学讲师；我的大部分时间都是为了研究而保护的。我的临床地位与我的研究目标是独一无二的协同。我的短期目标是通过K08项目进行一段时间的密集研究培训，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来支持独立研究奖的申请。我的长期目标是继续在分析开发方面进行转化性研究，专注于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、预防和管理方面的挑战。我的长期职业目标将需要额外的临床调查培训，以便我成为一名有效的翻译调查员。我已经与Ananth Karumachi博士和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著名的高级调查人员。环境：我与BIMDC和哈佛医学院的合作使我处于一流的研究环境中。我的部门为我的项目提供了独立的实验室空间和质谱仪仪器，用于执行分析开发和性能测试，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，我将在那里学习人类受试者研究和生物统计学方面的培训。我可以获得的资源包括哈佛CTSC的支持。如果我被授予K08支持，我将有资格注册临床 通过哈佛大学公共卫生学院的临床有效性暑期项目进行研究，并攻读公共卫生硕士学位。我的系主任杰弗里·萨菲兹不遗余力地为年轻的研究人员提供了一个有教养的研究环境。研究：尿素衍生氰酸盐对蛋白质的氨甲基化可能导致慢性和终末期肾病(ESRD)的并发症。我们假设蛋白质的氨甲酰化是由时间平均尿素浓度和氰酸盐清除剂(如游离氨基酸)之间的平衡决定的。在这里，我们报告了在人血清白蛋白中发现了一个特定的氨甲酰化位点，并报道了用液相色谱和串联质谱仪测定氨基甲酸化白蛋白(%C-Alb)的方法。当我们分析患者样本中的%C-Alb时，我们发现在血液透析第一年死亡的终末期肾病患者的%C-Alb水平高于幸存者，并且%C-Alb水平的升高与全因死亡率显著相关(风险比3.76P=0.0002)。虽然%C-Alb水平与预期的平均血尿素浓度呈正相关，但我们发现%C-Alb水平与许多血清氨基酸浓度呈同样强烈的负相关。提示维持性血液透析患者体内氨基酸缺乏可能与蛋白质氨甲基化有关，氨基酸补充剂可用于血液透析患者的治疗，以抑制蛋白质氨甲基化及其后遗症。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，但尚不清楚这是否源于氨甲酰化。以前的研究也表明，氨甲酰化可以抑制硫醇抗氧化剂的作用。氧化应激增加与慢性肾脏疾病、动脉粥样硬化和尿毒症心肌病有关，但目前尚不清楚氨甲酰化是否与尿毒症相关的氧化应激及其心血管病理有关。我们最近在《科学》杂志上发表了这些结果。地中海医院。和CJASN，我们目前正在通过一项试点临床试验来跟踪这些研究，测试氨基酸氨基甲酰化清除剂对血液透析患者蛋白质氨基甲基化的影响。在这项建议中，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“高氨甲基化”治疗方法。具体目标1将使用肾功能衰竭和动脉粥样硬化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将利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。特殊目标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并改善尿毒症相关的心脏病。具体目标4将测试一种硫醇抗氧化剂--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.