Platelet activation in septic shock

描述(由申请人提供)：迈克尔·普斯卡里奇，医学博士，密西西比大学医学中心急诊医学系助理教授，将利用这一K-23奖转变为一名独立的以患者为导向的研究人员。Puskarich博士在同行评议的期刊上发表了18篇论文，在获得K-23奖之前，他将完成德雷塞尔大学临床研究硕士学位课程。他的职业目标是成为一名在转化性急救医学研究方面拥有国家公认专业知识的领先临床科学家。为候选人、医学博士Michael Puskarich制定的指导计划本质上是全面的，旨在适应Puskarich博士在该奖项的项目期间向独立研究调查员的过渡。他的导师团队包括一位主要导师Alan E.Jones医学博士、一位共同导师George Dale博士和一个由Jonathan Holser博士、Jeffrey Kline医学博士、Merry Lindsey博士和Richard Summers医学博士组成的学员咨询委员会。他们共同拥有广泛的专业知识和经验，为应聘者提供其职业发展所需的工具。普斯卡里奇博士和他的导师们一起，为他成功的职业发展确定了几个目标。这些包括(1)提高他在临床和翻译性脓毒症研究方面的专业知识和经验；(2)提高他的翻译研究技巧；(3)提高他在血小板、微循环和线粒体生理学方面的知识；(4)获得更多的科学和拨款撰写经验；(5)提高他作为学术领袖的地位；以及(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，其中包括正式的课程、专门的培训、参加研讨会和研讨会、积极参与专业协会和大学范围内的委员会、定期与他的导师和他的学员咨询委员会成员举行会议，以及完成他的研究研究。已经确定了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博士提议的研究项目是对 一个正在进行的由NIGMS资助的项目(R01GM103799-01)，Puskarich博士的主要导师担任PI。这项辅助研究已经得到了母研究的dsmb的批准，并在人类受试者保护部分包括了一封支持信。母研究L-卡尼汀治疗血管加压药依赖型败血症休克的主要目的是评估L-卡尼汀能否降低感染性休克患者的累积器官衰竭和预测死亡率。这项研究设计是一项随机、双盲、安慰剂对照、剂量/疗效寻找试验，利用贝叶斯适应性方法和反应适应性随机化。在感染性休克诊断的24小时内，患者被随机分为三种剂量的L-卡尼汀(6克、12克或18克)或安慰剂中的一种12小时输注，并跟踪观察结果。来自全美10家医院的多达250名患者将参与其中，这项研究目前正处于患者登记的第一年。Puskarich博士将能够利用母研究的基础设施，探索未包括在母研究中的研究领域；具体地说，高激活(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-卡尼汀对细胞呼吸和HA血小板形成的影响。这项研究旨在 实现三个具体目标：目标1：确定脓毒症患者体外DA刺激后产生的HA血小板百分比是否高于对照组，并确定这一百分比是否与微循环血流指数(MFI)和序贯器官衰竭评估(SOFA)评分有关。假设脓毒症增加了血小板在凝血酶和惊厥毒素(一种胶原蛋白模拟物)双重激动剂(DA)刺激下高度激活的倾向。这一体外测量反映了脓毒症的体内环境，其特点是循环中的凝血酶和内皮损伤较高，并暴露于内皮下胶原。由于HA血小板是高度促凝剂，其形成的增加将促进微循环血栓形成和器官衰竭。目的#2：确定脓毒症患者体外SA刺激后产生的HA血小板百分比是否高于对照组，是否与漏气呼吸相关，并与MFI和SOFA评分相关。假设在脓毒症引起的活性氧(ROS)损伤后，仅用凝血酶进行SA刺激后，一部分血小板准备发生HA转变，这是漏氧呼吸增加的证据。这部分血小板反过来又进一步导致微循环血栓形成和器官衰竭。目的#3：测试与安慰剂相比，L-卡尼汀治疗是否显著减少漏气呼吸和SA刺激的HA血小板形成，并伴随MFI和SOFA评分的改善。假设L-卡尼汀治疗将减少SA刺激的HA血小板的形成，但不减少DA刺激的HA血小板的形成，并伴随着血栓形成和器官衰竭的减少。L-卡尼汀可减轻脓毒症引起的ROS损伤，减少SA刺激的HA血小板的形成。这种减少反过来可以减轻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.