Differences in enteric neuronal density in the NSE-Noggin mouse model across institutes

The enteric nervous system (ENS) is a large and complex part of the peripheral nervous system, and it is vital for gut homeostasis. To study the ENS, different hyper- and hypo-innervated model systems have been developed. The NSE-Noggin mouse model was described as one of the few models with a higher enteric neuronal density in the colon. However, in our hands NSE-Noggin mice did not present with a hyperganglionic phenotype. NSE-Noggin mice were phenotyped based on fur appearance, genotyped and DNA sequenced to demonstrate transgene and intact NSE-Noggin-IRES-EGFP construct presence, and RNA expression of Noggin was shown to be upregulated. Positive EGFP staining in the plexus of NSE-Noggin mice also confirmed Noggin protein expression. Myenteric plexus preparations of the colon were examined to quantify both the overall density of enteric neurons and the proportions of enteric neurons expressing specific subtype markers. The total number of enteric neurons in the colonic myenteric plexus of transgenic mice did not differ significantly from wild types, nor did the proportion of calbindin, calretinin, or serotonin immunoreactive myenteric neurons. Possible reasons as to why the hyperinnervated phenotype could not be observed in contrast with original studies using this mouse model are discussed, including study design, influence of microbiota, and other environmental variables.</p

The emerging role of nerves and glia in colorectal cancer

The role of the nervous system as a contributor in the tumor microenvironment has been recognized in different cancer types, including colorectal cancer (CRC). The gastrointestinal tract is a highly innervated organ system, which is not only innervated by the autonomic nervous system, but also contains an extensive nervous system of its own; the enteric nervous system (ENS). The ENS is important for gut function and homeostasis by regulating processes such as fluid absorption, blood flow, and gut motility. Dysfunction of the ENS has been linked with multiple gastrointestinal

In vivo transplantation of enteric neural crest cells into mouse gut; Engraftment, functional integration and long-term safety

Objectives: Enteric neuropathies are severe gastrointestinal disorders with unsatisfactory outcomes. We aimed to investigate the potential of enteric neural stem cell therapy approaches for such disorders by transplanting mouse enteric neural crest cells (ENCCs) into ganglionic and aganglionic mouse gut in vivo and analysing functional integration and long-term safety. Design: Neurospheres gene

Neuronal Distribution in Colorectal Cancer:Associations With Clinicopathological Parameters and Survival

Over the past years, insights in the cancer neuroscience field increased rapidly, and a potential role for neurons in colorectal carcinogenesis has been recognized. However, knowledge on the neuronal distribution, subtypes, origin, and associations with clinicopathological characteristics in human studies is sparse. In this study, colorectal tumor tissues from the Netherlands Cohort Study on diet and cancer (n = 490) and an in-cohort validation population (n = 529) were immunohistochemically stained for the pan-neuronal markers neurofilament (NF) and protein gene product 9.5 (PGP9.5) to study the association between neuronal marker expression and clinicopathological characteristics. In addition, tumor and healthy colon tissues were stained for neuronal subtype markers, and their immunoreactivity in colorectal cancer (CRC) stroma was analyzed. NF-positive and PGP9.5-positive nerve fibers were found within the tumor stroma and mostly characterized by the neuronal subtype markers vasoactive intestinal peptide and neuronal nitric oxide synthase, suggesting that inhibitory neurons are the most prominent neuronal subtype in CRC. NF and PGP9.5 protein expression were not consistently associated with tumor stage, sublocation, differentiation grade, and median survival. NF immunoreactivity was associated with a worse CRC-specific survival in the study cohort (P = .025) independent of other prognostic factors (hazard ratio, 2.31; 95% CI, 1.33-4.03; P = .003), but these results were not observed in the in-cohort validation group. PGP9.5, in contrast, was associated with a worse CRC-specific survival in the in-cohort validation (P = .046) but not in the study population. This effect disappeared in multivariate analyses (hazard ratio, 0.81; 95% CI, 0.50-1.32; P = .393), indicating that this effect was dependent on other prognostic factors. This study demonstrates that the tumor stroma of CRC patients mainly harbors inhibitory neurons and that NF as a single marker is significantly associated with a poorer CRC-specific survival in the study cohort but necessitates future validation.</p

Chronic intra-uterine Ureaplasma parvum infection induces injury of the enteric nervous system in ovine fetuses

Background: Chorioamnionitis, inflammation of the fetal membranes during pregnancy, is often caused by intra-amniotic (IA) infection with single or multiple microbes. Chorioamnionitis can be either acute or chronic, and is associated with adverse postnatal outcomes of the intestine, including necrotizing enterocolitis (NEC). Neonates with NEC have structural and functional damage to the intestinal mucosa and the enteric nervous system (ENS), with loss of enteric neurons and glial cells. Yet, the impact of acute, chronic or repetitive antenatal inflammatory stimuli on the development of the intestinal mucosa and ENS has not been studied. The aim of this study is therefore to investigate the effect of acute, chronic and repetitive microbial exposure on the intestinal mucosa, submucosa and ENS in premature lambs. Materials and Methods: A sheep model of pregnancy was used in which the ileal mucosa, submucosa and ENS were assessed following IA exposure to lipopolysaccharide (LPS) for 2 or 7 days (acute), Ureaplasma parvum (UP) for 42 days (chronic) or repetitive microbial exposure (42 days UP with 2 or 7 days LPS). Results: IA LPS exposure for 7 days or IA UP exposure for 42 days caused intestinal injury and inflammation in the mucosal and submucosal layer of the gut. Repetitive microbial exposure did not further aggravate injury of the terminal ileum. Chronic IA UP exposure caused significant structural ENS alterations characterized by loss of PGP9.5 and S100β immunoreactivity whereas these changes were not found after re-exposure of chronic UP-exposed fetuses to LPS for 2 or 7 days. Conclusion: The in utero loss of PGP9.5 and S100β immunoreactivity following chronic UP exposure corresponds with intestinal changes in neonates with NEC, and may therefore form a novel mechanistic explanation for the association of chorioamnionitis and NEC

Tuning the activity of the enteric nervous system, a role for both endogenous and exogenous mediators

Om de verschillende gastro-intestinale functies min of meer onafhankelijk van het centraal zenuwstelsel te kunnen coördineren bezit ons spijsverteringskanaal een eigen bezenuwing. Dit enterisch zenuwstelsel (EZS) is gelegen in de darmwand en bevat verschillende types enterische zenuwcellen die georganiseerd zijn in speciale circuits. Klassiek gezien, worden deze netwerken geactiveerd via het prikkelen van intrinsieke sensorische neuronen die de zogenoemde intestinale reflex starten en zodoende de typische motiliteitspatronen initiëren. Recent onderzoek geeft echter aan dat enterische neuronale circuits multifunctionele netwerken zijn die naast input van intrinsiek sensorische neuronen ook nog andere informatie ontvangen. De output van deze circuits blijkt bovendien grotendeels bepaald te worden door het geïntegreerde activiteitsniveau van verschillende populaties enterische neuronen die communiceren via multi-synaptische contacten. Onze hypothese was dan ook dat het moduleren van courante netwerk activiteit en synaptische communicatie door zowel endogene als exogene mediatoren een belangrijke rol speelt in het bepalen van de output van het EZS. Met behulp van beeldvorming van intracellulaire Ca2+ huishouding en synaptische activiteit in enterische neuronen, konden we aantonen dat zowel intrinsieke als extrinsieke mediatoren het potentieel hebben om het activiteitsniveau van het EZS te beïnvloeden. We vonden dat de bezenuwing van ons spijsverteringsstelsel een endogeen cannabinoid systeem bevat dat het activiteitsniveau van het enterisch zenuwstelsel mee helpt bepalen. Verder stelden we vast dat de neuronale groeifactor brain-derived neurotrophic factor in tegenstelling tot zenuwcellen van de hippocampus, enterische neuronen niet direct activeert, maar eerder de signaaloverdracht tussen enterische neuronen onderling bevordert. Het lijkt daarom aannemelijk dat deze modulerende effecten de oorzaak zijn van het stimulerend effect op gastro-intestinale motiliteit. Naast intrinsieke mediatoren, kunnen ook stoffen afkomstig van planten, die mogelijk werken door het activeren van TRP kanalen, invloed hebben op enterische zenuw activiteit. Van bepaalde bestanddelen die aanwezig zijn in onze voeding, zoals menthol, is het immers geweten dat ze gastro-intestinale motiliteit beïnvloeden. Onze data geven aan dat het effect van zulke stoffen op enterische zenuwcellen en synaptische transmissie misschien wel één van de onderliggende mechanismen zou kunnen zijn. We concluderen dat de regulatie van EZS activiteit door zowel endogene als exogene mediatoren de uiteindelijke output van het enterische zenuwstelsel sterk kan bepalen. Verder onderzoek zal moeten uitwijzen of dergelijke mechanismen een gelijkaardige rol spelen in de humane gastro-intestinale fysiologie en of het interfereren met deze mechanismen kan gebruikt worden voor therapeutische doeleinden.status: publishe