Platelet activation in septic shock

描述（由申请人提供）：迈克尔Puskarich，医学博士，在密西西比医学中心的急诊医学系的大学助理教授，将利用这个K-23奖过渡到一个独立的面向患者的研究人员。Puskarich博士在同行评审期刊上发表了18篇论文，在获得K-23奖之前，他将完成德雷克塞尔大学的临床研究硕士学位课程。他的职业目标是成为一名领先的临床科学家，在转化急救医学研究方面拥有全国公认的专业知识。为候选人Michael Puskarich博士制定的指导计划在本质上是全面的，旨在适应Puskarich博士在该奖项项目期间向独立研究调查员的过渡。他的指导团队包括一个主要的导师，艾伦E。Jones，MD;共同导师，乔治戴尔，博士;和学员咨询委员会，由乔纳森霍尔瑟，博士，杰弗里克莱恩，医学博士，梅里林赛，博士和理查德萨默斯，医学博士。他们共同拥有广泛的专业知识和经验，为候选人提供专业发展所需的工具。Puskarich博士与他的导师一起确定了他成功职业发展的几个目标。这些包括（1）提高他在临床和转化脓毒症研究方面的专业知识和经验;（2）提高他的转化研究技术;（3）提高他对血小板，微循环和线粒体生理学的知识;（4）获得更多的科学和资助写作经验;（5）提高他作为学术领袖的地位;（6）成为他人的有效导师。Puskarich博士将通过严格的职业发展计划来实现这些目标，该计划包括正式课程，专业培训，参加研讨会和研讨会，积极参与专业协会和大学委员会，定期与他的导师和他的学员咨询委员会成员举行会议，并完成他的研究。已确定Puskarich博士每项职业发展活动的里程碑和估计分配的专业时间。Puskarich博士提出的研究项目是一项辅助研究， 一个正在进行的NIGMS资助的项目（R 01 GM 103799 -01），Puskarich博士的主要导师担任PI。辅助研究已获得母研究DSMB的批准，支持函包含在人类受试者保护章节中。母研究的主要目的，左旋卡尼汀治疗血管加压素依赖性脓毒性休克”（更常见的是称为快速管理的左旋卡尼汀sEpsis或RACE研究）是评估是否左旋卡尼汀减少累积器官衰竭和预测概率的死亡率与脓毒性休克患者。研究设计是一项随机、双盲、安慰剂对照、剂量/疗效探索试验，采用贝叶斯自适应方法和反应自适应随机化。在诊断为感染性休克的24小时内，患者被随机分配至12小时输注三种剂量的L-肉毒碱（6、12或18克）或安慰剂中的一种，并随访结果。来自美国10家医院的多达250名患者将参与，该研究目前正处于患者招募的第一年。Puskarich博士将能够利用母研究的基础设施，探索母研究中未包括的调查领域;特别是，高度活化（HA）血小板在脓毒症中的作用;血小板线粒体功能改变在脓毒症发病机制中的意义;以及L-肉毒碱对细胞呼吸和HA血小板形成的影响。本研究旨在 实现三个具体目标：目标一：确定与匹配的对照组相比，脓毒症患者体外DA刺激后产生的HA血小板百分比是否增加，并确定该百分比是否与微循环血流指数（MFI）和序贯器官衰竭评估（SOFA）评分相关。假设是脓毒症增加了血小板在体外用凝血酶和惊厥素（一种胶原模拟物）双重激动剂（DA）刺激后高度活化的倾向。这种体外测量反映了脓毒症的体内环境，其特征在于高循环凝血酶和内皮损伤，以及内皮下胶原蛋白的暴露。由于HA血小板是高度促凝的，其形成的增加将促进微循环血栓形成和器官衰竭。目标二：:确定与匹配对照相比，脓毒症患者体外SA刺激后生成的HA血小板百分比是否增加，是否与漏气呼吸相关，以及是否与MFI和SOFA评分相关。该假设是，血小板的一个子集是准备的HA转换后，SA刺激凝血酶单独继发于败血症诱导的活性氧（ROS）损伤，证明了泄漏呼吸增加。血小板的这一亚群进而进一步导致微循环血栓形成和器官衰竭。目标3：测试与安慰剂相比，左旋卡尼汀治疗是否显著降低漏呼和SA刺激的HA血小板形成，并伴随MFI和SOFA评分的改善。假设L-肉毒碱治疗将减少SA刺激的HA血小板形成，但不会减少DA刺激的HA血小板形成，同时减少血栓形成和器官衰竭。左旋卡尼汀降低脓毒症诱导的ROS损伤，减少SA刺激的HA血小板的形成。这种减少反过来又减轻了微循环血栓形成和器官衰竭。

DESCRIPTION (provided by applicant): Michael Puskarich, MD, an Assistant Professor in the University of Mississippi Medical Center's Department of Emergency Medicine, will utilize this K-23 Award to transition into an independent patient-oriented researcher. Author of 18 publications in peer-reviewed journals, Dr. Puskarich will have completed Drexel University's Master's degree program in Clinical Research prior to receipt of his K-23 Award. His career goal is to be a leading clinician scientist with nationally recognized expertise in translational emergency medicine research. The Mentoring Plan developed for the candidate, Michael Puskarich, MD, is comprehensive in nature and designed to accommodate Dr. Puskarich's transition to an independent research investigator during this award's project period. His mentoring team includes a Primary Mentor, Alan E. Jones, MD; a Co-Mentor, George Dale, PhD; and a Mentee Advisory Committee, consisting of Jonathan Holser, PhD, Jeffrey Kline, MD, Merry Lindsey, PhD, and Richard Summers, MD. Together, they have the breadth of expertise and experience to provide the candidate with the tools he needs for his professional development. Together with his mentors, Dr. Puskarich has identified several objectives for his successful career development. These include (1) advancing his expertise and experience in clinical and translational sepsis research; (2) enhancing his translational research techniques; (3) advancing his knowledge of platelet, microcirculatory, and mitochondrial physiology; (4) gaining additional experience in scientific and grant writing; (5) enhancing his standing as an academic leader; and (6) becoming an effective mentor to others. Dr. Puskarich will accomplish these objectives through a rigorous career development plan that includes formal coursework, specialized training, attendance at workshops and seminars, active participation in professional societies and on university-wide committees, regular scheduled meetings with his mentors and members of his Mentee Advisory Committee, and completion of his research study. Milestones and estimated allocation of Dr. Puskarich's professional time for each of his career development activities have been identified. Dr. Puskarich's proposed research project is an ancillary study of an ongoing NIGMS-funded project (R01GM103799-01), for which Dr. Puskarich's primary mentor serves as PI. The ancillary study has been approved by the parent study's DSMB, and a letter of support is included in the Protection of Human Subjects section. The primary aim of the parent study, L-Carnitine Treatment for Vasopressor Dependent Septic Shock" (more commonly referred to as the Rapid Administration of Carnitine in sEpsis-or RACE Study) is to assess whether L-carnitine reduces cumulative organ failure and predicted probability of mortality in patients with septic shock. The study design is that of a randomized, double-blind, placebo-controlled, dose/efficacy-finding trial that utilizes a Bayesian adaptive approach and response-adaptive randomization. Within 24 hours of the diagnosis of septic shock, patients are randomized to a 12 hour infusion of one of three doses of L-carnitine (6, 12, or 18 grams) or placebo and followed to outcome. Up to 250 patients from 10 hospitals throughout the U.S. will be participating, and the study is currently in its first year of patient enrollment. Dr. Puskarichwill be able to take advantage of the infrastructure of the parent study and explore areas of inquiry not included in the parent study; specifically, the role of highly activated (HA) platelets in sepss; the significance of altered platelet mitochondrial function in the pathogenesis of sepsis; and the effects of L- carnitine on cellular respiration and HA platelet formation. The study is designed to achieve three specific aims: Aim #1: Determine if the percentage of HA platelets generated following DA stimulation in vitro is increased in patients with sepsis compared to matched controls, and determine if this percentage is associated with microcirculatory flow index (MFI) and Sequential Organ Failure Assessment (SOFA) score. The hypothesis is that sepsis increases the propensity for platelets to become highly activated following dual-agonist (DA) stimulation with thrombin and convulxin (a collagen mimetic) in vitro. This in vitro measurement reflects the in vivo environment in sepsis, which is characterized by high circulating thrombin and endothelial damage, with exposure of subendothelial collagen. As HA platelets are highly procoagulant, an increase in their formation will promote microcirculatory thrombosis and organ failure. Aim #2: : Determine if the percentage of HA platelets generated following SA stimulation in vitro is increased in patients with sepsis compared to matched controls, is associated with leak respiration, and is associated with MFI and SOFA score. The hypothesis is that a subset of platelets is primed for a HA transition following SA-stimulation with thrombin alone secondary to sepsis-induced reactive oxygen species (ROS) injury, evidenced by increased leak respiration. This subset of platelets, in turn, further contributes to microcirculatory thrombosis and organ failure. Aim #3: Test if L-carnitine treatment significantly decreases leak respiration and SA-stimulated HA platelet formation compared to placebo, with concomitant improvements in MFI and SOFA score. The hypothesis is that L-carnitine treatment will decrease SA-stimulated, but not DA-stimulated HA platelet formation, with concomitant decreases in thrombosis and organ failure. L-carnitine decreases sepsis-induced ROS damage, decreasing formation of SA-stimulated HA platelets. This decrease, in turns, mitigates microcirculatory thrombosis and organ failure.