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

每年约有200万美国成年人患上败血症，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，35,000名退伍军人因败血症住院，其中约80%的人存活到 出院(目前的数字可能更高)。退伍军人的再住院率也很高 在脓毒症之后。与治疗脓毒症相关的医院费用超过240亿美元/年，使其成为世界上 在美国治疗昂贵的疾病面对昂贵和负担沉重的患者护理，势在必行 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。老鼠 是生物医学研究中使用的最重要的工具之一，部分原因是它们能够对复杂的 人类的生理系统。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小鼠生物学之间的关系 评估免疫系统的健康状况。人类自然地接触到共生微生物和致病微生物。 从出生起，成年人类的免疫系统就受到每种微生物的训练和塑造。在……里面 相比之下，实验室小鼠通常被关在特定的无病原体(SPF)条件下。SPF住房有 有助于提高实验的重复性，但它同时也进一步疏远了 来自人类的小鼠模型，很大程度上是因为SPF小鼠在有限的微生物暴露下生活。我们的 该计划将利用一种新的小鼠模型，模拟人类免疫系统的关键方面--其中 暴露在多种持续和已消除的感染中是常态。我们将整合转录学， 代谢组学、蛋白质组学和细胞因子图谱，以确定病理生理学和 脓毒症消退。 拟议的验证研究将是支持使用具有微生物经验的“脏”小鼠的关键 败血症研究。没有报道直接比较肮脏的脓毒症小鼠和人类的免疫反应。 病人。我们假设，将脓毒症患者的急性反应与肮脏的小鼠的脓毒症模型进行直接比较将 显示出比人类和SPF小鼠之间的比较更密切的相关性。有观点认为，啮齿动物 模型与人类脓毒症的病理生理学并不相似，这一假设得到了研究的支持，研究声称 在人类败血症中观察到的分子变化与在啮齿类动物中观察到的不同。然而，啮齿类动物 系统是一个宝贵的工具，可以促进目前对免疫系统的理解，从而产生 了解败血症病理的重要信息，并为寻求改善脓毒症的方法提供线索 条件。对脏老鼠提出的主要担忧是共生关系中变异性增加的可能性。 以及他们所遇到的致病微生物。如果一种新的小鼠模型用于生物医学 这项研究是为了更好地模拟具有不同微生物体验的人类，然后使用具有类似 不同的微生物接触史必须被视为一种优势。需要强调的是，肮脏的老鼠是 旨在作为一种新的补充，而不是取代通常用于脓毒症研究的SPF小鼠。 我们将肮脏的老鼠视为发现新的有效败血症疗法的宝贵工具，这些疗法可能对 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.