Megacolon

BackgroundHirschsprung's disease (HSCR) is a serious congenital bowel disorder with a prevalence of 1/5000. Currently, there is a lack of systematically developed guidelines to assist clinical decision-making regarding diagnostics and management.AimsThis guideline aims to cover the diagnostics and management of rectosigmoid HSCR up to adulthood. It aims to describe the preferred approach of ERNICA, the European Reference Network for rare inherited and congenital digestive disorders.MethodsRecommendations within key topics covering the care pathway for rectosigmoid HSCR were developed by an international workgroup of experts from 8 European countries within ERNICA European Reference Network from the disciplines of surgery, medicine, histopathology, microbiology, genetics, and patient organization representatives. Recommendation statements were based on a comprehensive review of the available literature and expert consensus. AGREE II and GRADE approaches were used during development. Evidence levels and levels of agreement are noted.ResultsThirty-three statements within 9 key areas were generated. Most recommendations were based on expert opinion.ConclusionIn rare or low-prevalence diseases such as HSCR, there remains limited availability of high-quality clinical evidence. Consensus-based guidelines for care are presented.

Hirschsprung's disease is a neurocristopathy, caused by defective migration, proliferation, differentiation and survival of neural crest cells, leading to gut aganglionosis. It usually manifests rapidly after birth, affecting 1 in 5000 live births around the globe. In recent decades, there has been a significant improvement in the understanding of its genetics and the association with other congenital anomalies, which share the pathomechanism of improper development of the neural crest. Apart from that, several cell populations which do not originate from the neural crest, but contribute to the development of Hirschsprung's disease, have also been described, namely mast cells and interstitial cells of Cajal. From the diagnostic perspective, researchers also focused on "Variants of Hirschsprung's disease", which can mimic the clinical signs of the disease, but are in fact different entities, with distinct prognosis and treatment approaches. The treatment of Hirschsprung's disease is usually surgical resection of the aganglionic part of the intestine, however, as many as 30-50% of patients experience persisting symptoms. Considering this fact, this review article also outlines future hopes and perspectives in Hirschsprung's disease management, which has the potential to benefit from the advancements in the fields of cell-based therapy and tissue engineering.

The development of the enteric nervous system (ENS) is highly modulated by the synchronized interaction between the enteric neural crest cells (ENCCs) and the neural stem cell niche comprising the gut microenvironment. Genetic defects dysregulating the cellular behaviour(s) of the ENCCs result in incomplete innervation and hence ENS dysfunction. Hirschsprung disease (HSCR) is a rare complex neurocristopathy in which the enteric neural crest-derived cells fail to colonize the distal colon. In addition to ENS defects, increasing evidence suggests that HSCR patients may have intrinsic defects in the niche impairing the extracellular matrix (ECM)-cell interaction and/or dysregulating the cellular niche factors necessary for controlling stem cell behaviour. The niche defects in patients may compromise the regenerative capacity of the stem cell-based therapy and advocate for drug- and niche-based therapies as complementary therapeutic strategies to alleviate/enhance niche-cell interaction. Here, we provide a summary of the current understandings of the role of the enteric neural stem cell niche in modulating the development of the ENS and in the pathogenesis of HSCR. Deciphering the contribution of the niche to HSCR may provide important implications to the development of regenerative medicine for HSCR.

Hirschsprung disease (HSCR) is a congenital condition characterized by the improper migration of enteric neural crest cells, leading to aganglionosis most commonly in the rectosigmoid colon. This severe and life-threatening disorder often results in the development of Hirschsprung-associated enterocolitis (HAEC), which can occur either before or after surgical resection of the affected bowel segment. Using colonic tissue from patients with HSCR alongside the well-established endothelin receptor B knockout mouse model, we investigated epithelial regeneration dynamics and stromal-epithelial cross-talk in the distal ganglionic colon, a critical site for HAEC development. In individuals with HSCR but without epithelial damage, the distal ganglionic colon displayed impaired epithelial regeneration and alteration of intestinal stem cell dynamics, characterized by the reduction of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5+) epithelial stem cells. This phenomenon was consistent in the mouse model, where impaired regenerative ability preceded HAEC when epithelial damage occurred on site. Patients with HSCR also exhibited remodeling in stromal cells in this distal ganglionic colon region, with fewer primary sources of Wingless-related integration site (Wnt) signal-releasing stromal cells and the exclusive presence of proinflammatory (matrix metalloproteinase 1+) stromal cells. Stromal cells from the HSCR distal ganglionic colon failed to sustain the growth of colonic organoids. However, ibuprofen suppressed the proinflammatory stromal cells, leading to effective restoration of epithelial organoid growth. These observations underscore the crucial role of impaired stromal-epithelial cross-talk in HSCR and the pathogenesis of HAEC and suggest potential therapeutic targets for the prevention or treatment of the condition.