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：我们的目标是改善患有先天性巨结肠症 (HSCR) 的儿童的生活，这是一种致命的疾病肠道末端缺乏肠神经系统 (ENS) 的威胁性出生缺陷。 ENS 调节肠道功能的大部分方面，缺乏 ENS 的“神经节”肠道无法正常工作。症状包括顽固性便秘、胆汁性呕吐、腹胀、生长障碍和 HSCR- 相关性小肠结肠炎 (HAEC) 是除肠道外最危险的问题。炎症期间，HAEC 期间，细菌可能会穿过肠上皮，导致致命的败血症。 HSCR 的主要治疗方法是拉穿手术，切除无神经节肠并重新连接含有 ENS 的肠管不幸的是，大约 35% 的儿童在拉出后仍然存在问题。手术，包括 HAEC，一个长期存在的谜团是为什么症状的出现和严重程度差异如此之大。特别是患有 HSCR 的儿童，有些儿童从未患有 HAEC，但其他儿童则重复出现 HAEC。拉穿手术前后的发作情况、神经节缺失的长度、遗传差异和手术细节。饮食、肠道微生物等非遗传因素的影响无疑会影响 HAEC 风险和 HSCR 结果。肠道内的小分子几乎没有在 HSCR 或使用 Piebald 模型中进行过研究。致死性 sl/sl 小鼠，一种成熟的 HSCR 模型，我们发现两种小鼠的生存率存在 5 倍差异小鼠设施的存活率差异与无神经节肠的长度、不同的遗传学或死亡原因，并且我们不进行手术，相反，生存差异反映了基本方面。 HSCR 病理生理学可被环境中的非遗传因素改变。由于 sl/sl 小鼠喂食不同类型的食物并且具有不同的肠道，因此出现 5 倍的生存差异每个机构的微生物差异可能会改变肠道内的小分子。许多小分子，包括食物中的营养素和微生物代谢物，都会以多种方式影响肠屏障功能目标 1 检验饮食和微生物通过交换饮食影响生存的假设。各机构sl/sl，制作无菌小鼠，并利用粪便将粪便移植到无菌小鼠体内来自各个机构的新初步数据表明，简单地改变饮食即可显着改变 sl/sl 的生存率。目标 2 使用解剖学和功能学定义了机构间肠屏障 sl/sl 的差异。接近并识别穿过肠上皮导致脓毒症的微生物，目标 3 定义了粘膜。肠腔内可能影响屏障功能的相关微生物和小分子。完成这项研究后，我们将知道是否可以通过控制饮食或肠道微生物来提高 HSCR 患者的生存率模型并将具有改变脓毒症风险的明确机制，然后可以利用这些数据进行设计。人体临床试验旨在改善 HSCR 儿童的预后并减少 HAEC 的发生。