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Neurogastroenterology and Motility Nov 2023Early-life events impact maturation of the gut microbiome, enteric nervous system, and gastrointestinal motility. We examined three regions of gastric tissue to...
BACKGROUND
Early-life events impact maturation of the gut microbiome, enteric nervous system, and gastrointestinal motility. We examined three regions of gastric tissue to determine how maternal separation and gut microbes influence the structure and motor function of specific regions of the neonatal mouse stomach.
METHODS
Germ-free and conventionally housed C57BL/6J mouse pups underwent timed maternal separation (TmSep) or nursed uninterrupted (controls) until 14 days of life. We assessed gastric emptying by quantifying the progression of gavaged fluorescein isothiocyanate (FITC)-dextran. With isolated rings of forestomach, corpus, and antrum, we measured tone and contractility by force transduction, gastric wall thickness by light microscopy, and myenteric plexus neurochemistry by whole-mount immunostaining.
KEY RESULTS
Regional gastric sampling revealed site-specific differences in contractile patterns and myenteric plexus structure. In neonatal mice, TmSep prolonged gastric emptying. In the forestomach, TmSep increased contractile responses to carbachol, decreased muscularis externa and mucosa thickness, and increased the relative proportion of myenteric plexus nNOS+ neurons. Germ-free conditions did not appreciably alter the structure or function of the neonatal mouse stomach and did not impact the changes caused by TmSep.
CONCLUSIONS AND INFERENCES
A regional sampling approach facilitates site-specific investigations of murine gastric motor physiology and histology to identify site-specific alterations that may impact gastrointestinal function. Delayed gastric emptying in TmSep is associated with a thinner muscle wall, exaggerated cholinergic contractile responses, and increased proportions of inhibitory myenteric plexus nNOS+ neurons in the forestomach. Gut microbes do not profoundly affect the development of the neonatal mouse stomach or the gastric pathophysiology that results from TmSep.
Topics: Mice; Animals; Animals, Newborn; Gastroparesis; Maternal Deprivation; Mice, Inbred C57BL; Stomach; Myenteric Plexus; Disease Models, Animal; Gastric Emptying
PubMed: 37772676
DOI: 10.1111/nmo.14676 -
Scientific Reports Dec 2023Previously, the presence of a blood-myenteric plexus barrier and its disruption was reported in experimentally induced colitis via a macrophage-dependent process. The...
Previously, the presence of a blood-myenteric plexus barrier and its disruption was reported in experimentally induced colitis via a macrophage-dependent process. The aim of this study is to reveal how myenteric barrier disruption and subsequent neuronal injury affects gut motility in vivo in a murine colitis model. We induced colitis with dextran sulfate sodium (DSS), with the co-administration of liposome-encapsulated clodronate (L-clodronate) to simultaneously deplete blood monocytes contributing to macrophage infiltration in the inflamed muscularis of experimental mice. DSS-treated animals receiving concurrent L-clodronate injection showed significantly decreased blood monocyte numbers and colon muscularis macrophage (MM) density compared to DSS-treated control (DSS-vehicle). DSS-clodronate-treated mice exhibited significantly slower whole gut transit time than DSS-vehicle-treated animals and comparable to that of controls. Experiments with oral gavage-fed Evans-blue dye showed similar whole gut transit times in DSS-clodronate-treated mice as in control animals. Furthermore, qPCR-analysis and immunofluorescence on colon muscularis samples revealed that factors associated with neuroinflammation and neurodegeneration, including Bax1, Hdac4, IL-18, Casp8 and Hif1a are overexpressed after DSS-treatment, but not in the case of concurrent L-clodronate administration. Our findings highlight that MM-infiltration in the muscularis layer is responsible for colitis-associated dysmotility and enteric neuronal dysfunction along with the release of mediators associated with neurodegeneration in a murine experimental model.
Topics: Mice; Animals; Clodronic Acid; Colitis; Inflammation; Macrophages; Colon; Dextran Sulfate; Mice, Inbred C57BL; Disease Models, Animal
PubMed: 38105266
DOI: 10.1038/s41598-023-50059-7 -
The Journal of Pathology Jun 2022SARS-CoV-2, the causative agent of COVID-19, typically manifests as a respiratory illness, although extrapulmonary involvement, such as in the gastrointestinal tract and...
SARS-CoV-2, the causative agent of COVID-19, typically manifests as a respiratory illness, although extrapulmonary involvement, such as in the gastrointestinal tract and nervous system, as well as frequent thrombotic events, are increasingly recognised. How this maps onto SARS-CoV-2 organ tropism at the histological level, however, remains unclear. Here, we perform a comprehensive validation of a monoclonal antibody against the SARS-CoV-2 nucleocapsid protein (NP) followed by systematic multisystem organ immunohistochemistry analysis of the viral cellular tropism in tissue from 36 patients, 16 postmortem cases and 16 biopsies with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 status from the peaks of the pandemic in 2020 and four pre-COVID postmortem controls. SARS-CoV-2 anti-NP staining in the postmortem cases revealed broad multiorgan involvement of the respiratory, digestive, haematopoietic, genitourinary and nervous systems, with a typical pattern of staining characterised by punctate paranuclear and apical cytoplasmic labelling. The average time from symptom onset to time of death was shorter in positively versus negatively stained postmortem cases (mean = 10.3 days versus mean = 20.3 days, p = 0.0416, with no cases showing definitive staining if the interval exceeded 15 days). One striking finding was the widespread presence of SARS-CoV-2 NP in neurons of the myenteric plexus, a site of high ACE2 expression, the entry receptor for SARS-CoV-2, and one of the earliest affected cells in Parkinson's disease. In the bone marrow, we observed viral SARS-CoV-2 NP within megakaryocytes, key cells in platelet production and thrombus formation. In 15 tracheal biopsies performed in patients requiring ventilation, there was a near complete concordance between immunohistochemistry and PCR swab results. Going forward, our findings have relevance to correlating clinical symptoms with the organ tropism of SARS-CoV-2 in contemporary cases as well as providing insights into potential long-term complications of COVID-19. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
Topics: COVID-19; Humans; Megakaryocytes; Myenteric Plexus; Neurons; SARS-CoV-2
PubMed: 35107828
DOI: 10.1002/path.5878 -
Oncology Letters May 2021Gastrointestinal schwannoma is a rare, slow-growing and benign tumor that mostly originates in the Auerbach myenteric nerve plexus in the gastrointestinal tract. The... (Review)
Review
Gastrointestinal schwannoma is a rare, slow-growing and benign tumor that mostly originates in the Auerbach myenteric nerve plexus in the gastrointestinal tract. The clinical manifestations may be associated with the location, size, differentiation type, and degree of malignancy of the tumor. Endoscopy, ultrasound and imaging examinations serve an important auxiliary role in the clinical identification, diagnosis and differential diagnosis of lesions; assessment of risk; and preparation for surgery. S-100 positivity is a hallmark of schwannoma. CD34, CD117, discovered on GIST-1, P53, ALK, β-catenin, smooth muscle actin and Desmin negativity are helpful for the identification of other gastrointestinal stromal tumors. Surgical removal of the tumor is the main treatment for schwannoma. Benign gastrointestinal schwannoma has a good prognosis without recurrence and metastasis; malignant transformation is extremely rare and has a poor prognosis.
PubMed: 33777207
DOI: 10.3892/ol.2021.12645 -
Anatomical Record (Hoboken, N.J. : 2007) Sep 2023The enteric nervous system, a major subdivision of the autonomic nervous system, is known for its neurochemical heterogeneity and complexity. The myenteric plexus, one...
The enteric nervous system, a major subdivision of the autonomic nervous system, is known for its neurochemical heterogeneity and complexity. The myenteric plexus, one of its two principal components, primarily controls peristalsis and its dysfunction may lead to a number of gastrointestinal motility disorders. The myenteric neurons have been described to use a wide variety of neurotransmitters although no evidence has been reported for the existence of adrenergic neurons in the hindgut. This study aims at elucidating the chemical coding of neurons in the myenteric plexus of the rat colon and anorectal region with particular emphasis on cholinergic and the so-called nonadrenergic, noncholinergic (NANC) transmitter systems. The immunostaining for choline acetyltransferase revealed an intense staining of the myenteric ganglia with clear delineation of their neuronal cell bodies and without local distributional differences in the colonic region. The myenteric ATPergic structures were mostly limited to fiber bundles surrounding unstained myenteric neurons and penetrating the two muscle layers. We also observed an abundance of intensely stained varicose substance P-immunopositive fibers, ensheathing the immunonegative myenteric neuronal cell bodies in a basket-like manner. Applying NADPH-diaphorase histochemistry and nitric oxide synthase immunohistochemistry, we were able to demonstrate numerous nitrergic somata of myenteric neurons with Dogiel Type I morphology. Apart from the observed nitrergic distributional patterns, no distinct variations were found in the staining intensity or distribution of myenteric structures in the colon and anorectal area. Our results suggest that myenteric neurons in the distal intestinal portion utilize a broad spectrum of enteric transmitters, including classical and NANC transmitters.
Topics: Animals; Rats; Myenteric Plexus; Enteric Nervous System; Neurons; Intestines; Nitric Oxide Synthase; Colorectal Neoplasms
PubMed: 35716375
DOI: 10.1002/ar.25019 -
Autonomic Neuroscience : Basic &... Nov 2021The enteric nervous system controls much of the mixing and propulsion of nutrients along the digestive tract. Enteric neural circuits involve intrinsic sensory neurons,... (Review)
Review
The enteric nervous system controls much of the mixing and propulsion of nutrients along the digestive tract. Enteric neural circuits involve intrinsic sensory neurons, interneurons and motor neurons. While the role of the excitatory motor neurons is well established, the role of the enteric inhibitory motor neurons (IMNs) is less clear. The discovery of inhibitory transmission in the intestine in the 1960's in the laboratory of Geoff Burnstock triggered the search for the unknown neurotransmitter. It has since emerged that most neurons including the IMNs contain and may utilise more than one transmitter substances; for IMNs these include ATP, the neuropeptide VIP/PACAP and nitric oxide. This review distinguishes the enteric neural pathways underlying the 'standing reflexes' from the pathways operating physiologically during propulsive and non-propulsive movements. Morphological evidence in small laboratory animals indicates that the IMNs are located in the myenteric plexus and project aborally to the circular muscle, where they act by relaxing the muscle. There is ongoing 'tonic' activity of these IMNs to keep the intestinal muscle relaxed. Accommodatory responses to content further activate enteric pathways that involve the IMNs as the final neural element. IMNs are activated by mechanical and chemical stimulation induced by luminal contents, which activate intrinsic sensory enteric neurons and the polarised interneuronal ascending excitatory and descending inhibitory reflex pathways. The latter relaxes the muscle ahead of the advancing bolus, thus facilitating propulsion.
Topics: Animals; Enteric Nervous System; Gastrointestinal Motility; Intestine, Small; Motor Neurons; Myenteric Plexus
PubMed: 34329834
DOI: 10.1016/j.autneu.2021.102854 -
Science (New York, N.Y.) Nov 2023Glial cells in the gut are specialized to fine-tune intestinal function.
Glial cells in the gut are specialized to fine-tune intestinal function.
Topics: Neuroglia; Intestines; Animals; Mice; Myenteric Plexus
PubMed: 37917691
DOI: 10.1126/science.adk3883 -
Brain Research Jul 2021This study aims to explore the effect of chronic central neuropeptide-S (NPS) treatment on gastrointestinal dysmotility and the changes of cholinergic neurons in the...
This study aims to explore the effect of chronic central neuropeptide-S (NPS) treatment on gastrointestinal dysmotility and the changes of cholinergic neurons in the dorsal motor nucleus of the vagus (DMV) of a Parkinson's disease (PD) rat model. The PD model was induced through a unilateral medial forebrain bundle (MFB) administration of the 6-hydroxydopamine (6-OHDA). Locomotor activity (LMA), solid gastric emptying (GE), and gastrointestinal transit (GIT) were measured 7 days after the surgery. NPS was daily administered (1 nmol, icv, 7 days). In substantia nigra (SN), dorsal motor nucleus of the vagus (DMV), and gastric whole-mount samples, changes in tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS), glial fibrillary acidic protein (GFAP), NPS receptor (NPSR), and alpha-synuclein (Ser129) were examined by immunohistochemistry. Cuprolinic blue staining was used to evaluate the number of neuronal cells in myenteric ganglia. The GIT rate, the total number of myenteric neurons, and the expressions of ChAT, nNOS, TH, and GFAP in the myenteric plexus were not changed in rats that received the 6-OHDA. Chronic NPS treatment reversed 6-OHDA-induced impairment of the motor performance, and GE, while preventing the loss of dopaminergic and cholinergic neurons in SN and DMV, respectively. NPS attenuated 6-OHDA-induced α-syn (Ser129) pathology both in SN and DMV. Additionally, expression of NPSR protein was detected in gastro-projecting cells in DMV. Taken together, centrally applied NPS seems to prevent 6-OHDA-induced gastric dysmotility through a neuroprotective action on central vagal circuitry.
Topics: Animals; Choline O-Acetyltransferase; Gastric Emptying; Gastrointestinal Motility; Injections, Intraventricular; Locomotion; Male; Neuropeptides; Oxidopamine; Rats; Rats, Wistar; Receptors, Neuropeptide; Tyrosine 3-Monooxygenase; Vagus Nerve
PubMed: 33753063
DOI: 10.1016/j.brainres.2021.147442 -
The American Journal of Gastroenterology Aug 2019Involvement of the gastrointestinal (GI) tract is an infrequent extrathoracic presentation of sarcoidosis. We reviewed 305 cases of GI involvement reported in 238... (Review)
Review
Involvement of the gastrointestinal (GI) tract is an infrequent extrathoracic presentation of sarcoidosis. We reviewed 305 cases of GI involvement reported in 238 patients, in whom GI sarcoidosis was the first sign of the disease in half the cases. The disease does not affect the GI tract uniformly, with a clear oral-anal gradient (80% of reported cases involved the esophagus, stomach, and duodenum). Clinicopathological mechanisms of damage may include diffuse mucosal infiltration, endoluminal exophytic lesions, involvement of the myenteric plexus, and extrinsic compressions. Ten percent of patients presented with asymptomatic or subclinical disease found on endoscopy. The diagnosis is relevant clinically because 22% of cases reviewed presented as life threatening. In addition, initial clinical/endoscopic findings may be highly suggestive of GI cancer. The therapeutic approach is heterogeneous and included wait-and-see or symptomatic approaches, glucocorticoid/immunosuppressive therapy, and surgery. Sarcoidosis of the gut is a heterogeneous, potentially life-threatening condition that requires a multidisciplinary approach and early clinical suspicion to institute personalized therapeutic management and follow-up.
Topics: Deglutition Disorders; Duodenal Diseases; Endoscopy, Gastrointestinal; Esophageal Achalasia; Esophageal Diseases; Esophageal Mucosa; Gastrointestinal Diseases; Glucocorticoids; Humans; Ileal Diseases; Immunosuppressive Agents; Jejunal Diseases; Lymphadenopathy; Mediastinum; Myenteric Plexus; Myotomy; Polyps; Proton Pump Inhibitors; Sarcoidosis; Stomach Diseases
PubMed: 30865014
DOI: 10.14309/ajg.0000000000000171 -
Cells May 2024Intestinal homeostasis results from the proper interplay among epithelial cells, the enteric nervous system (ENS), interstitial cells of Cajal (ICCs), smooth muscle...
Intestinal homeostasis results from the proper interplay among epithelial cells, the enteric nervous system (ENS), interstitial cells of Cajal (ICCs), smooth muscle cells, the immune system, and the microbiota. The disruption of this balance underpins the onset of gastrointestinal-related diseases. The scarcity of models replicating the intricate interplay between the ENS and the intestinal epithelium highlights the imperative for developing novel methods. We have pioneered a sophisticated tridimensional in vitro technique, coculturing small intestinal organoids with myenteric and submucosal neurons. Notably, we have made significant advances in (1) refining the isolation technique for culturing the myenteric plexus, (2) enhancing the isolation of the submucosal plexus-both yielding mixed cultures of enteric neurons and glial cells from both plexuses, and (3) subsequently co-culturing myenteric and submucosal neurons with small intestinal organoids. This co-culture system establishes neural innervations with intestinal organoids, allowing for the investigation of regulatory interactions in the context of gastrointestinal diseases. Furthermore, we have developed a method for microinjecting the luminal space of small intestinal organoids with fluorescently labeled compounds. This technique possesses broad applicability such as the assessment of intestinal permeability, transcytosis, and immunocytochemical and immunofluorescence applications. This microinjection method could be extended to alternative experimental setups, incorporating bacterial species, or applying treatments to study ENS-small intestinal epithelium interactions. Therefore, this technique serves as a valuable tool for evaluating the intricate interplay between neuronal and intestinal epithelial cells (IECs) and shows great potential for drug screening, gene editing, the development of novel therapies, the modeling of infectious diseases, and significant advances in regenerative medicine. The co-culture establishment process spans twelve days, making it a powerful asset for comprehensive research in this critical field.
Topics: Animals; Mice; Coculture Techniques; Gastrointestinal Tract; Intestine, Small; Myenteric Plexus; Neurons; Organoids; Submucous Plexus
PubMed: 38786037
DOI: 10.3390/cells13100815