Each year, approximately 170 babies in the UK are born with Hirschsprung's disease (HSCR). Affected babies develop an intestinal blockage, which can be life threatening, due to missing nerve cells in the lower part of their intestine (called 'aganglionic' intestine). Currently, the only treatment is surgical removal of the affected segment of the intestine. However, after surgery up to 75% of children with HSCR suffer from constipation or incontinence, and 10% of children require a permanent artificial opening of the intestine. Thus, there is a need to improve the treatment of babies and children with HSCR. We have isolated stem cells from normal segments of intestine, cultured them in a sterile dish and have shown that these cells can become nerve cells which are able to regulate bowel activity under laboratory conditions. Surprisingly, we have recently demonstrated that similar stem cells can also be found in the aganglionic segments of intestine of children with HSCR, which lack nerve cells. This novel finding opens up exciting new questions for treatment options: Is it possible to transplant the patient's own stem cells, after converting them in to nerve cells in the laboratory? Can the stem cells, while still present in the aganglionic segments of intestine, be stimulated to become new nerve cells? These possibilities could improve surgical outcomes or avoid surgery altogether. Based on these findings, the overarching aim of this project is to develop new approaches to treat patients with Hirschsprung's disease. As our previous observations showed that the stem cells present in the aganglionic intestine also give rise to nerves similar to those from normal gut, our current work is focussed on establishing to what extent the stem cells from the aganglionic intestine are the same as those from normal gut. It is also important to understand whether the stem cells isolated from aganglionic intestine can be controlled to make sure that they do not form tumours after they have been stimulated. Therefore, the main focus of the proposed project is to determine the mechanisms which regulate the behaviour of these new stem cells. This information is necessary before we can consider any use of the stem cells in therapies for patients. In this project we will isolate stem cells in the laboratory from tissue samples obtained at surgery from children with and without HSCR. Once the stem cells are isolated, they are cultured under laboratory conditions. The next step will be to assess whether the same mechanisms that regulate the behaviour of stem cells in normal bowel, also control the change of stem cells derived from aganglionic HSCR bowel in to functioning nerves in culture. Once we know what these mechanisms are, we will be able to use specific drugs to regulate the behaviour of the HSCR stem cells in order to convert them into the nerves necessary to restore normal function to the bowel. The information gained from this project is an essential prerequisite for clinical trials to test the efficacy of the stem cells isolated from aganglionic bowel to be used in stem cell therapies. Many children with Hirschsprung's disease face a lifetime of psychological, social and physical difficulties affecting them and their families. Improved outcomes from the proposed treatment have the potential to permanently change the lives of children and reduce the demands on health and social services.