Integrated use of genomics, metabolomics, and cytokine profiling to validate the use of 'dirty' mice to study sepsis pathophysiology

每年约有200万成年美国人患上败血症，近27万美国人死于败血症。 2009年，在美国退伍军人管理局卫生系统中，超过35，000名退伍军人因败血症住院，约80%的人存活至 出院（目前的数字可能更高）。退伍军人的再入院率也很高 脓毒症之后与治疗脓毒症相关的医院费用超过240亿美元/年，使其成为最 面对昂贵而繁重的病人护理， 以更好地了解这些患者所经历的病理生理状态，从而提供有针对性的护理。小鼠 是生物医学研究中最重要的工具之一，部分原因是它们能够模拟复杂的 人体的生理系统。然而，环境微生物暴露是一个重要的区别 在使用小鼠模型时必须考虑的基本人类和实验室小鼠生物学之间的差异， 评估免疫系统的适应性人类自然地暴露于肠道和病原微生物 每种微生物从出生起每天都在生长，成年人的免疫系统也是由每种微生物训练和塑造的。在 相比之下，实验室小鼠通常被饲养在无特定病原体（SPF）的条件下。SPF住房具有 有助于提高实验的可重复性，但同时也进一步疏远了 小鼠模型，主要是因为SPF小鼠的生活与有限的微生物接触。我们 该提案将利用一种新型的小鼠模型，该模型模拟了人类免疫系统的关键方面， 暴露于多个正在进行和已解决的感染是常态。我们将整合转录组学， 代谢组学、蛋白质组学和细胞因子谱分析，以确定病理生理学的分子基础， 脓毒症消退。 拟议的验证研究将是支持使用微生物经验丰富的“脏”小鼠的关键， 败血症研究。目前还没有关于脏脓毒症小鼠与人类免疫反应的直接比较的报道 患者我们认为，直接比较脓毒症患者的急性反应与脏鼠脓毒症模型， 显示出比人类和SPF小鼠之间的比较更密切的相关性。有人认为啮齿动物 模型不类似于人类败血症的病理生理学，这一假设得到了声称 在人脓毒症中观察到的分子变化不同于在啮齿动物中观察到的分子变化。然而， 系统是一个宝贵的工具，以促进目前的理解免疫系统，将产生 重要的信息，了解脓毒症病理学，并提供线索，寻求方法，以改善 条件关于脏老鼠的主要担忧是， 以及他们遇到的致病微生物。如果一个新的小鼠模型用于生物医学的意图 研究是为了更好地模拟具有不同微生物经历的人类，然后使用具有类似微生物经历的小鼠。 不同的微生物暴露史必须被视为一种优势。重要的是要强调脏老鼠是 这意味着作为一种新的补充，而不是取代，SPF小鼠通常用于脓毒症研究。 我们认为脏小鼠是发现新的有效脓毒症疗法的有价值的工具， 微生物暴露后的环境扰动。

Each year ~2 million adult Americans develop sepsis and nearly 270,000 Americans die as a result of sepsis. In the U.S. VA health system in 2009, >35,000 Veterans were hospitalized with sepsis, and ~80% survived to hospital discharge (current numbers are likely higher). Veterans also have a high rate of hospital readmission following sepsis. Hospital costs associated with treating sepsis exceed $24B/year, making it the most expensive medical condition treated in the U.S. Faced with costly and burdensome patient care, it is imperative to better understand the pathophysiologic states experienced by these patients to deliver targeted care. Mice are one of the most important tools used in biomedical research, due in part to their ability to model complex physiological systems in humans. However, environmental microbial exposure is an important difference between basic human and laboratory mouse biology that must be considered when using mouse models to evaluate immune system fitness. Humans are naturally exposed to both commensal and pathogenic microbes daily from birth, and the immune system of adult humans has been trained and shaped by each microbe. In contrast, laboratory mice are often housed under specific pathogen-free (SPF) conditions. SPF housing has been instrumental in increasing experimental reproducibility, but it has simultaneously further distanced the mouse model from humans, largely because SPF mice live their lives with limited microbial exposure. Our proposal will leverage a novel mouse model that mimics critical aspects of the human immune system – where exposure to multiple ongoing and resolved infections is the norm. We will integrate transcriptomics, metabolomics, proteomics, and cytokine profiling to define the molecular basis of the pathophysiology and resolution of sepsis. The proposed validation studies will be key for supporting the use of microbially-experienced ‘dirty’ mice in sepsis research. There are no reported direct comparisons of immune responses in dirty septic mice to human patients. We posit that direct comparison of acute response in septic patients to sepsis models in dirty mice will show a closer correlation than the comparison between human and SPF mice. It has been argued that rodent models do not resemble the pathophysiology of human sepsis, an assumption boosted by studies claiming the molecular changes observed in human sepsis are different from the ones observed in rodents. Yet, the rodent system is an invaluable tool to advance current understanding of the immune system that will produce important information to understand septic pathology and provide clues for seeking ways to ameliorate the conditions. The main concern raised about dirty mice is the potential of increased variability in the commensal and pathogenic microbes they have encountered. If one intention of new mouse models for biomedical research is to better model humans with a diverse microbial experience, then using mice with a similarly diverse microbial exposure history must be viewed as a strength. It is important to emphasize dirty mice are meant to serve as a novel complement to, rather than replace, the SPF mice typically used in sepsis research. We see dirty mice as a valuable tool for discovering new efficacious sepsis therapies that may be sensitive to the environmental perturbations after microbial exposure.