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Frontiers in Physiology 2023A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are... (Review)
Review
A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.
PubMed: 37711458
DOI: 10.3389/fphys.2023.1239278 -
Nature Communications Aug 2023Achalasia is a rare motility disorder of the esophagus caused by the gradual degeneration of myenteric neurons. Immune-mediated ganglionitis has been proposed to...
Achalasia is a rare motility disorder of the esophagus caused by the gradual degeneration of myenteric neurons. Immune-mediated ganglionitis has been proposed to underlie the loss of myenteric neurons. Here, we measure the immune cell transcriptional profile of paired lower esophageal sphincter (LES) tissue and blood samples in achalasia and controls using single-cell RNA sequencing (scRNA-seq). In achalasia, we identify a pattern of expanded immune cells and a specific transcriptional phenotype, especially in LES tissue. We show C1QC macrophages and tissue-resident memory T cells (T), especially ZNF683 CD8 T and XCL1 CD4 T, are significantly expanded and localized surrounding the myenteric plexus in the LES tissue of achalasia. C1QC macrophages are transcriptionally similar to microglia of the central nervous system and have a neurodegenerative dysfunctional phenotype in achalasia. T also expresses transcripts of dysregulated immune responses in achalasia. Moreover, inflammation increases with disease progression since immune cells are more activated in type I compared with type II achalasia. Thus, we profile the immune cell transcriptional landscape and identify C1QC macrophages and T as disease-associated immune cell subsets in achalasia.
Topics: Humans; Esophageal Achalasia; Esophageal Sphincter, Lower; Neurons; Inflammation; Macrophages
PubMed: 37542039
DOI: 10.1038/s41467-023-39750-5 -
Alimentary Pharmacology & Therapeutics Jun 2024Hirschsprung's disease (HD) is a rare congenital disease that is characterised by the absence of ganglion cells in the myenteric plexus starting in the distal bowel....
BACKGROUND
Hirschsprung's disease (HD) is a rare congenital disease that is characterised by the absence of ganglion cells in the myenteric plexus starting in the distal bowel. This results in distal functional obstruction and may lead to complications like enterocolitis. The treatment is surgical and requires the resection of the aganglionic segment, and the pull-through of normal intestine into the anal opening. However, even after successful surgery, patients may continue to have symptoms.
AIM
Discuss current surgical techniques and management strategies for patients with postoperative symptoms after surgical correction of Hirschsprung's disease.
METHODS
A review of the literature was done through PubMed, with a focus on clinical management and approach.
RESULTS
We describe the clinical problems that can occur after surgical correction. These include obstructive symptoms, enterocolitis, or faecal incontinence. A systematic approach for the evaluation of these patients includes the exclusion of anatomic, inflammatory, behavioural or motility related factors. Depending on the severity of the symptoms, the evaluation includes examination under anaesthesia, the performance of contrast studies, endoscopic studies, measurement of anal sphincter function and colonic motility studies. The treatment is focused towards addressing the different pathophysiological mechanisms, and may include medical management, botulinum toxin to the anal sphincter or rarely redo-operation.
CONCLUSIONS
Patients with Hirschsprung's disease need to have surgical correction, and their postoperative long-term management is complex given a variety of associated problems that can occur after surgery. A systematic evaluation is necessary to provide appropriate therapy.
PubMed: 38922939
DOI: 10.1111/apt.18068 -
Journal of Crohn's & Colitis Jan 2024Pain is a cardinal symptom in inflammatory bowel disease [IBD]. An important structure in the transduction of pain signalling is the myenteric plexus [MP]. Nevertheless,...
BACKGROUND AND AIMS
Pain is a cardinal symptom in inflammatory bowel disease [IBD]. An important structure in the transduction of pain signalling is the myenteric plexus [MP]. Nevertheless, IBD-associated infiltration of the MP by immune cells lacks in-depth characterisation. Herein, we decipher intra- and periganglionic immune cell infiltrations in Crohn´s disease [CD] and ulcerative colitis [UC] and provide a comparison with murine models of colitis.
METHODS
Full wall specimens of surgical colon resections served to examine immune cell populations by either conventional immuno-histochemistry or immunofluorescence followed by either bright field or confocal microscopy. Results were compared with equivalent examinations in various murine models of intestinal inflammation.
RESULTS
Whereas the MP morphology was not significantly altered in IBD, we identified intraganglionic IBD-specific B cell- and monocyte-dominant cell infiltrations in CD. In contrast, UC-MPs were infiltrated by CD8+ T cells and revealed a higher extent of ganglionic cell apoptosis. With regard to the murine models of intestinal inflammation, the chronic dextran sulphate sodium [DSS]-induced colitis model reflected CD [and to a lesser extent UC] best, as it also showed increased monocytic infiltration as well as a modest B cell and CD8+ T cell infiltration.
CONCLUSIONS
In CD, MPs were infiltrated by B cells and monocytes. In UC, mostly CD8+ cytotoxic T cells were found. The chronic DSS-induced colitis in the mouse model reflected best the MP-immune cell infiltrations representative for IBD.
Topics: Animals; Mice; Colitis, Ulcerative; Crohn Disease; Myenteric Plexus; Inflammatory Bowel Diseases; Colitis; Neurotransmitter Agents; Pain; Inflammation
PubMed: 37565754
DOI: 10.1093/ecco-jcc/jjad122 -
Seminars in Neurology Aug 2023Nervous system disorders may be accompanied by gastrointestinal (GI) dysfunction. Brain lesions may be responsible for GI problems such as decreased peristalsis (e.g.,... (Review)
Review
Nervous system disorders may be accompanied by gastrointestinal (GI) dysfunction. Brain lesions may be responsible for GI problems such as decreased peristalsis (e.g., lesions in the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (e.g., lesions in the parabrachial nucleus), hiccupping and vomiting (e.g., lesions in the area postrema), and appetite loss (e.g., lesions in the hypothalamus). Decreased peristalsis also may be caused by lesions of the spinal long tracts or the intermediolateral nucleus projecting to the myenteric plexus. This review addresses GI dysfunction caused by multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein-associated disorder. Neuro-associated GI dysfunction may develop concurrently with brain or spinal cord dysfunction or may predate it. Collaboration between gastroenterologists and neurologists is highly desirable when caring for patients with GI dysfunction related to nervous system disorders, particularly since patients with these symptoms may visit a gastroenterologist prior to the establishment of a neurological diagnosis.
Topics: Humans; Multiple Sclerosis; Gastrointestinal Diseases; Myelin-Oligodendrocyte Glycoprotein; Basal Ganglia; Brain
PubMed: 37703888
DOI: 10.1055/s-0043-1771462 -
The Journal of Comparative Neurology Nov 2023Nociceptive afferent axons innervate the stomach and send signals to the brain and spinal cord. Peripheral nociceptive afferents can be detected with a variety of...
Nociceptive afferent axons innervate the stomach and send signals to the brain and spinal cord. Peripheral nociceptive afferents can be detected with a variety of markers (e.g., substance P [SP] and calcitonin gene-related peptide [CGRP]). We recently examined the topographical organization and morphology of SP-immunoreactive (SP-IR) axons in the whole mouse stomach muscular layer. However, the distribution and morphological structure of CGRP-IR axons remain unclear. We used immunohistochemistry labeling and applied a combination of imaging techniques, including confocal and Zeiss Imager M2 microscopy, Neurolucida 360 tracing, and integration of axon tracing data into a 3D stomach scaffold to characterize CGRP-IR axons and terminals in the whole mouse stomach muscular layers. We found that: (1) CGRP-IR axons formed extensive terminal networks in both ventral and dorsal stomachs. (2) CGRP-IR axons densely innervated the blood vessels. (3) CGRP-IR axons ran in parallel with the longitudinal and circular muscles. Some axons ran at angles through the muscular layers. (4) They also formed varicose terminal contacts with individual myenteric ganglion neurons. (5) CGRP-IR occurred in DiI-labeled gastric-projecting neurons in the dorsal root and vagal nodose ganglia, indicating CGRP-IR axons were visceral afferent axons. (6) CGRP-IR axons did not colocalize with tyrosine hydroxylase or vesicular acetylcholine transporter axons in the stomach, indicating CGRP-IR axons were not visceral efferent axons. (7) CGRP-IR axons were traced and integrated into a 3D stomach scaffold. For the first time, we provided a topographical distribution map of CGRP-IR axon innervation of the whole stomach muscular layers at the cellular/axonal/varicosity scale.
Topics: Animals; Mice; Calcitonin Gene-Related Peptide; Stomach; Axons; Neurons; Nerve Fibers
PubMed: 37694767
DOI: 10.1002/cne.25519 -
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