Expression of intermediate filament proteins and neuronal markers in the human fetal gut.

The human enteric nervous system (ENS) derives from migrating neural crest cells (NCC) and is structured into different plexuses embedded in the gastrointestinal tract wall. During development of the NCC, a rearrangement of various cytoskeletal intermediate filaments such as nestin, peripherin, or alpha-internexin takes place. Although all are related to developing neurons, nestin is also used to identify neural stem cells. Until now, information about the prenatal development of the human ENS has been very restricted, especially concerning potential stem cells. In this study the expression of nestin, peripherin, and alpha-internexin, but also of neuronal markers such as protein gene product (PGP) 9.5 and tyrosine hydroxylase, were investigated in human fetal and postnatal gut. The tissue samples were rapidly removed and subsequently processed for immunohistochemistry or immunoblotting. Nestin could be detected in all samples investigated with the exception of the 9th and the 12th week of gestation (WOG). Although the neuronal marker PGP9.5 was coexpressed with nestin at the 14th WOG, this could no longer be observed at later time points. Alpha-internexin and peripherin expression also did not appear before the 14th WOG, where they were coexpressed with PGP9.5. This study reveals that the intermediate filament markers investigated are not suitable to detect early neural crest stem cells.

Isolation and cultivation of neuronal precursor cells from the developing human enteric nervous system as a tool for cell therapy in dysganglionosis.

BACKGROUND: The human enteric nervous system (ENS) descends from migrating neural crest cells (NCC) and is structured into different plexuses embedded in the gastrointestinal tract wall. The development of this entity strongly depends on the supply of an appropriate support with trophic factors during organogenesis. The lack of important factors, such as glial cell line-derived neurotrophic factor, leads to severe disturbances in the ENS and, thus, to motility disorders in children. The isolation of neuronal precursor cells as well as their transplantation after expansion in vitro is therefore a hopeful new approach concerning all forms of dysganglionosis in children. METHODS: We therefore established a way to isolate and expand precursor cells from the developing and postnatal human ENS. Bowel samples were obtained from human fetuses and children (from the 9th week of gestation to 5 years postnatal). Myenteric plexus was isolated by enzymatical digestion and cultivated until spheroid aggregates, the so-called neurospheres, developed. These neurospheres could be differentiated and also be transplanted after dissociation into aganglionic bowel in vitro. RESULTS: Enteric neurospheres could be grown from different gestational ages, including postmortem material. Undifferentiated proliferating precursor cells were kept in culture for up to 72 days and could be differentiated in neurons and glial cells in vitro. CONCLUSION: The first results using isolated enteric neurospheres in aganglionic bowel are quite promising and are a basis to develop an appropriate cell therapy for all kinds of dysganglionosis, especially for cases where a surgical approach is not sufficient or not even possible.