Defining non-genetic mechanisms that prevent death in a Hirschsprung disease mouse model

定义预防先天性巨结肠症小鼠模型死亡的非遗传机制

基本信息

批准号：
10277960
负责人：
ROBERT O HEUCKEROTH
金额：
$ 57.63万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-27 至 2025-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10277960
关键词：
Abdomen Affect Anatomy Bacteria Biological Assay Cause of Death Cell physiology Cessation of life Child Clinical Trials Colon Complex Congenital Abnormality Congenital Megacolon Constipation Dangerousness Data Defect Diet Dietary Component Disease Distal Enteric Nervous System Enterocolitis Environment Epithelial Epithelial Cells Excision Exclusive Breastfeeding Failure Feces Food Functional disorder Genetic Germ-Free Goals Growth Human In Vitro Inbreeding Inflammation Institution Intestines Length Life Microbe Modeling Mucins Mucous body substance Mus Nervous system structure Nutrient Operative Surgical Procedures Outcome Pediatric Hospitals Philadelphia Piebaldism Positioning Attribute Postoperative Period Probiotics Property Proteins Quebec RNA Recurrence Risk Sepsis Severities Symptoms Testing Time Transition zone of anal mucous membrane Transplantation Universities Vomiting antimicrobial peptide beneficial microorganism design fecal transplantation feeding gut microbes human data improved improved outcome in vivo innovation microbial mouse model mucosal microbiota non-genetic novel therapeutic intervention premature prevent small molecule

项目摘要

Project Summary: Our goal is to improve the lives of children with Hirschsprung disease (HSCR), a life- threatening birth defect where the enteric nervous system (ENS) is absent from the end of the bowel. Because the ENS regulates most aspects of bowel function, “aganglionic” bowel that lacks ENS does not work well. Symptoms include intractable constipation, bilious vomiting, abdominal distension, growth failure and HSCR- associated enterocolitis (HAEC). HAEC is the most dangerous problem because in addition to bowel inflammation, during HAEC, bacteria may move across the bowel epithelium causing sepsis that can be fatal. Primary treatment for HSCR is pull-through surgery to remove aganglionic bowel and re-attach ENS-containing bowel to near the anal verge. Unfortunately, ~35% of children continue to have problems after pull-through surgery, including HAEC. One long-standing mystery is why symptom onset and severity differ so much among children with HSCR. In particular, some children never have HAEC, but other children have repeated HAEC episodes before and after pull-through surgery. Length of aganglionosis, genetic differences, and surgical details undoubtedly impact HAEC risk and HSCR outcomes. The impact of non-genetic factors like diet, gut microbes and small molecules inside the bowel have barely been investigated in HSCR or in HSCR models. Using Piebald lethal sl/sl mice, a well-established HSCR model, we discovered a 5-fold difference in survival between two mouse facilities. The survival difference is not related to the length of aganglionic bowel, distinct genetics, or cause of death, and we do not perform surgery. Instead, the survival difference reflects fundamental aspects of HSCR pathophysiology that can be altered by non-genetic factors in the environment. We hypothesized that the 5-fold survival difference occurs because sl/sl mice are fed different types of food and have different bowel microbes at each institution. Differences in diet and gut microbes can alter small molecules within the bowel. Many small molecules including nutrients in food and microbial metabolites impact bowel barrier function in ways that affect sepsis risk. Aim 1 tests the hypothesis that diet and microbes affect survival by swapping diets fed to sl/sl at each institution, making germ-free mice, and performing fecal transplant into germ-free mice using stool from each institution. New preliminary data suggest that simply changing diet markedly alters survival in sl/sl mice. Aim 2 defines how the bowel barrier differs in sl/sl between institutions using anatomic and functional approaches and identifies microbes that cross bowel epithelium to cause sepsis. Aim 3 defines mucosa- associated microbes and small molecules within the bowel lumen that could affect barrier function. At the completion of this study we will know if diet or gut microbes can be manipulated to improve survival in HSCR models and will have defined mechanisms that alter sepsis risk. These data can then be leveraged to design human clinical trials to improve outcomes in children with HSCR and reduce HAEC occurrence.

项目摘要：我们的目标是改善Hirschsprung病儿童（HSCR）的生活，这是一种生活 - 肠道末端不存在肠神经系统（ENS）的威胁性出生缺陷。因为 ENS调节了肠功能的大多数方面，缺乏ENS的“ Aganglionic”肠道无法正常工作。症状包括棘手的便秘，胆汁呕吐，腹部膨胀，生长衰竭和hscr- 相关的小肠结肠炎（HAEC）。 HAEC是最危险的问题，因为除了碗炎症，在HAEC期间，细菌可能在肠上皮上移动，导致败血症可能致命。 HSCR的主要治疗方法是拉伸手术，以去除伴齿轮的肠和重新连接肠道到肛门边缘附近。不幸的是，〜35％的儿童在拉起后继续遇到问题手术，包括Haec。一个长期存在的神秘是为什么症状发作和严重程度如此之大 HSCR的孩子。特别是，有些孩子从来没有Haec，但其他孩子重复了HAEC 拉伸手术前后发作。剧本病，遗传差异和手术细节的长度无疑会影响HAEC风险和HSCR结果。饮食，肠道微生物等非遗传因素的影响在HSCR或HSCR模型中，几乎没有研究肠内的小分子。使用Piebald 致命的SL/SL小鼠是一种良好的HSCR模型，我们发现了两种生存率差异5倍鼠标设施。生存差异与Aganglionic肠的长度，不同的遗传学或死亡原因，我们不进行手术。相反，生存差异反映了可以通过环境中的非遗传因素改变的HSCR病理生理学。我们假设由于SL/SL小鼠被喂养不同类型的食物，并且有不同的肠子，因此发生了5倍生存差异每个机构的微生物。饮食和肠道微生物的差异会改变肠内的小分子。许多小分子，包括食物和微生物代谢物中的营养，以肠屏障的功能以方式 AIM 1检验了饮食和微生物通过交换饮食来影响生存的假设每个机构的SL/SL，制造无菌小鼠，并使用粪便进行粪便移植到无菌小鼠中来自每个机构。新的初步数据表明，简单地改变饮食会显着改变SL/SL的生存老鼠。 AIM 2定义了使用解剖和功能的机构之间的肠屏障在SL/SL中的区别接近和识别横断肠上皮引起败血症的微生物。 AIM 3定义粘膜 - 肠腔内可能影响屏障功能的相关微生物和小分子。在这项研究的完成，我们将知道是否可以操纵饮食或肠道微生物以提高HSCR的生存模型并将具有改变败血症风险的机制。然后可以利用这些数据来设计人类的临床试验可改善HSCR儿童的结局并减少HAEC的发生。