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Nature Protocols Aug 2022The enteric nervous system (ENS) is an extensive network of enteric neurons and glial cells that is intrinsic to the gut wall and regulates almost all aspects of... (Review)
Review
The enteric nervous system (ENS) is an extensive network of enteric neurons and glial cells that is intrinsic to the gut wall and regulates almost all aspects of intestinal physiology. While considerable advancement has been made in understanding the genetic programs regulating ENS development, there is limited understanding of the molecular pathways that control ENS function in adult stages. One of the limitations in advancing the molecular characterization of the adult ENS relates to technical difficulties in purifying healthy neurons and glia from adult intestinal tissues. To overcome this, we developed novel methods for performing transcriptomic analysis of enteric neurons and glia, which are based on the isolation of fluorescently labeled nuclei. Here we provide a step-by-step protocol for the labeling of adult mouse enteric neuronal nuclei using adeno-associated-virus-mediated gene transfer, isolation of the labeled nuclei by fluorimetric analysis, RNA purification and nuclear RNA sequencing. This protocol has also been adapted for the isolation of enteric neuron and glia nuclei from myenteric plexus preparations from adult zebrafish intestine. Finally, we describe a method for visualization and quantification of RNA in myenteric ganglia: Spatial Integration of Granular Nuclear Signals (SIGNS). By following this protocol, it takes ~3 d to generate RNA and create cDNA libraries for nuclear RNA sequencing and 4 d to carry out high-resolution RNA expression analysis on ENS tissues.
Topics: Animals; Cell Lineage; Enteric Nervous System; Mice; Neuroglia; RNA; Zebrafish
PubMed: 35676375
DOI: 10.1038/s41596-022-00697-4 -
World Journal of Diabetes Jun 2021This article is an extensive review that provides an update on the pathophysiology, symptoms, diagnosis, and treatment of diabetic gastroenteropathy. There is no... (Review)
Review
This article is an extensive review that provides an update on the pathophysiology, symptoms, diagnosis, and treatment of diabetic gastroenteropathy. There is no reported prevalence, but it has been described that patients with type 1 diabetes have a cumulative incidence at 10 years of 5.2%, and type 2 patients, 1%. Also, in the group of type 1 diabetes, it has been observed that women are more likely to present this condition (5.8% 3.5%). Many factors are associate with its development (, hyperglycemia, vagal dysfunction, loss of expression of neural nitric oxide synthase in the myenteric plexus, alterations in the Cajal interstitial cell network, and oxidative stress). Gastrointestinal discomfort could be perceived 70% higher in diabetic patients, describing that 25% of diabetic patients experience gastrointestinal symptoms. Diabetic enteropathy could affect any portion of the gastrointestinal tract, but esophageal alterations were described in more than 60% of diabetic patients, also 60% of them present constipation, and 20%, diarrhea. Gastric emptying scintigraphy is useful to evaluate gastroparesis, therefore, gastric retention of more than 60% at 2 h has a sensitivity of 100% and specificity of 20% for diagnosis; however, other studies such as breath tests, with a sensitivity of 89% and a specificity of 80%, or the endoscopic capsule contribute to the diagnosis. There is no cure; however, management must be multidisciplinary, focused on slowing the progression of diabetic gastroenteropathy, reducing symptoms, and restoring function; that includes nutritional recommendation, maintain glucose levels kept below 180 mg/dL, use of prokinetics, anti-emetics; nowadays, it has been special interest in surgical treatment, such as pyloroplasty, also gastric electrical stimulation appears to be another alternative.
PubMed: 34168729
DOI: 10.4239/wjd.v12.i6.794 -
The Journal of Pathology Nov 2022SARS-CoV-2 virus, the cause of COVID-19 disease, establishes infection in the human body via interaction with the angiotensin-converting enzyme 2 (ACE2) receptor on cell...
SARS-CoV-2 virus, the cause of COVID-19 disease, establishes infection in the human body via interaction with the angiotensin-converting enzyme 2 (ACE2) receptor on cell membranes. The lung is the major organ affected, and all respiratory epithelium from nose to alveolus is infectable. A recent study published in The Journal of Pathology looked at a wide range of other human tissues, mostly autopsy-derived, to identify susceptible cells. The virus (associated with ACE2) is found in all endothelial cells (an important finding), renal and biliary epithelium, in megakaryocytes, and occasionally in hepatocytes. It was not found in heart myofibres or brain neurones but is present in gut myenteric plexus cells. This work confirms previous work on SARS-CoV-2-infectable cells, and so supports investigations into the pathogenesis of COVID-19 disease as it affects (or does not directly affect) the different organs. © 2022 The Pathological Society of Great Britain and Ireland.
Topics: Angiotensin-Converting Enzyme 2; COVID-19; Endothelial Cells; Humans; SARS-CoV-2; Viral Tropism
PubMed: 36002997
DOI: 10.1002/path.6003 -
Current Neurology and Neuroscience... Oct 2020To review the peripheral neurological complications of the acute hepatic porphyrias, as well as the latest advances in their pathophysiology and management. (Review)
Review
PURPOSE OF REVIEW
To review the peripheral neurological complications of the acute hepatic porphyrias, as well as the latest advances in their pathophysiology and management.
RECENT FINDINGS
The diagnosis of porphyric neuropathy remains challenging as varying neuropathic patterns are encountered depending on disease stage, including a non-length-dependent distribution pattern. The major pathophysiologic mechanism is δ-aminolevulinic acid (ALA)-induced neurotoxicity. The less restrictive blood-nerve barrier in the autonomic ganglia and myenteric plexus may explain the frequency of dysautonomic manifestations. Recently, a prophylactic small interfering RNA (siRNA)-based therapy that reduces hepatic ALA Synthase-1 mRNA was approved for patients with recurrent neuro-visceral attacks. Neurologists should appreciate the varying patterns of porphyric neuropathy. As with most toxin-induced axonopathies, long-term outcomes depend on early diagnosis and treatment. While the short-term clinical and biochemical benefits of siRNA-based therapy are known, its long-term effects on motor recovery, chronic pain, and dysautonomic manifestations are yet to be determined.
Topics: Humans; Peripheral Nervous System Diseases; Polyneuropathies; Porphobilinogen Synthase; Porphyrias, Hepatic
PubMed: 33026560
DOI: 10.1007/s11910-020-01078-8 -
Journal of Thoracic Disease Aug 2019Achalasia is an uncommon disorder that results from the degeneration of ganglion cells of the myenteric plexus in the lower esophageal wall. It is manifested by a loss... (Review)
Review
Achalasia is an uncommon disorder that results from the degeneration of ganglion cells of the myenteric plexus in the lower esophageal wall. It is manifested by a loss of peristalsis in the lower part of the esophagus and failure of the lower esophageal sphincter (LES) to relax. Peroral endoscopic myotomy (POEM) is a minimally invasive intervention that aims to treat achalasia. It is regarded as the endoscopic equivalent of Heller myotomy. POEM is a form of natural orifice transluminal endoscopic surgery that is completed by creating a submucosal tunnel in the lower part of esophagus to reach the inner circular muscle bundles of the LES to perform myotomy, while preserving the outer longitudinal muscle bundles. The result is decreased resting pressure of the LES, facilitating the passage of ingested material. POEM was initially introduced to treat achalasia by targeting the LES. POEM has expanded to include gastric POEM (G-POEM), myotomy of the pyloric sphincter to treat gastroparesis, and per rectal endoscopic myotomy to treat adult Hirschsprung's disease.
PubMed: 31489229
DOI: 10.21037/jtd.2019.07.84 -
Dysphagia Jun 2021Chagas disease, caused by the infection of the protozoan parasite Trypanosoma cruzi, has clinical consequences in the heart and digestive tract. The most important... (Review)
Review
Chagas disease, caused by the infection of the protozoan parasite Trypanosoma cruzi, has clinical consequences in the heart and digestive tract. The most important changes in the digestive tract occur in the esophagus (megaesophagus) and colon (megacolon). Esophageal dysfunction in Chagas disease results from damage of the esophageal myenteric plexus, with loss of esophageal peristalsis, partial or absent lower esophageal sphincter relaxation, and megaesophagus, which characterizes secondary esophageal achalasia. The treatment options for the disease are similar to those for idiopathic achalasia, consisting of diet and behavior changes, drugs, botulinum toxin, peroral endoscopic myotomy (POEM), pneumatic dilation of the lower esophageal sphincter, laparoscopic Heller myotomy, and esophagectomy. Chagas disease causes a life-threatening cardiopathy, and this should be considered when choosing the most appropriate treatment for the disease. While some options are palliative, for temporary relief of dysphagia (such as drugs, botulinum toxin, and pneumatic dilation), other therapies provide a long-term benefit. In this case, POEM stands out as a modern and successful strategy, with good results in more than 90% of the patients. Esophagectomy is the option in Chagas disease patients with advanced megaesophagus, despite the increased risk of complications. In these cases, peroral endoscopic myotomy may be an option, which needs further evaluation.
Topics: Chagas Disease; Deglutition Disorders; Esophageal Achalasia; Esophageal Sphincter, Lower; Humans; Treatment Outcome
PubMed: 33855597
DOI: 10.1007/s00455-021-10297-1 -
The Journal of Histochemistry and... Jun 2023Gastrointestinal symptoms are common health problems found during aging and neurodegenerative diseases. Trimethyltin-induced rat is known as an animal model of...
Gastrointestinal symptoms are common health problems found during aging and neurodegenerative diseases. Trimethyltin-induced rat is known as an animal model of hippocampal degeneration with no data on enteric neurodegeneration. This study aimed to investigate the effect of trimethyltin (TMT) induction on the gastrointestinal tract. A 28-day animal study with male Sprague-Dawley rats (3 months old, 150-200 g) given a single TMT injection (8 mg/kg body weight, intraperitoneal) was conducted. The number of neurons in the colonic myenteric plexus was measured using stereological estimation. Histological scoring of colon inflammation, immunohistochemistry of tumor necrosis factor-α (TNF-α), and quantitative PCR were conducted. This study showed neuronal loss in the colonic myenteric plexus of TMT-induced rat model of neurodegeneration. Minor colon inflammation characterized by inflammatory cell infiltration and slightly higher expression of TNF-α in the colon mucosa were observed in the TMT-induced rat. However, the gut microbiota composition of the TMT-induced rat was not different from that of the control rats. This study demonstrates that TMT induces colonic myenteric plexus neurodegeneration and minor colon inflammation, which suggests the potential of this animal model to elucidate the communication between the gastrointestinal tract and central nervous system in neurodegenerative diseases.
Topics: Rats; Male; Animals; Myenteric Plexus; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha; Colon; Inflammation
PubMed: 37322890
DOI: 10.1369/00221554231182195 -
Physiological Reports Feb 2021Obesity is associated with the development of insulin resistance (IR) and type-2 diabetes mellitus (T2DM); however, not all patients with T2DM are obese. The... (Comparative Study)
Comparative Study
BACKGROUND
Obesity is associated with the development of insulin resistance (IR) and type-2 diabetes mellitus (T2DM); however, not all patients with T2DM are obese. The Goto-Kakizaki (GK) rat is an experimental model of spontaneous and non-obese T2DM. There is evidence that the intestine contributes to IR development in GK animals. This information prompted us to investigate small intestine remodeling in this animal model.
METHODS
Four-month-old male Wistar (control) and GK rats were utilized for the present study. After removing the small intestine, the duodenum, proximal jejunum, and distal ileum were separated. We then measured villi and muscular and mucosa layer histomorphometry, goblet cells abundance, total myenteric and submucosal neuron populations, and inflammatory marker expression in the small intestinal segments and intestinal transit of both groups of animals.
KEY RESULTS
We found that the GK rats exhibited decreased intestinal area (p < 0.0001), decreased crypt depth in the duodenum (p = 0.01) and ileum (p < 0.0001), increased crypt depth in the jejunum (p < 0.0001), longer villi in the jejunum and ileum (p < 0.0001), thicker villi in the duodenum (p < 0.01) and ileum (p < 0.0001), thicker muscular layers in the duodenum, jejunum, and ileum (p < 0.0001), increased IL-1β concentrations in the duodenum and jejunum (p < 0.05), and increased concentrations of NF-κB p65 in the duodenum (p < 0.01), jejunum and ileum (p < 0.05). We observed high IL-1β reactivity in the muscle layer, myenteric neurons, and glial cells of the experimental group. GK rats also exhibited a significant reduction in submucosal neuron density in the jejunum and ileum, ganglionic hypertrophy in all intestinal segments studied (p < 0.0001), and a slower intestinal transit (about 25%) compared to controls.
CONCLUSIONS
The development of IR and T2DM in GK rats is associated with small intestine remodeling that includes marked alterations in small intestine morphology, local inflammation, and reduced intestinal transit.
Topics: Animals; Blood Glucose; Cytokines; Diabetes Mellitus, Type 2; Disease Models, Animal; Duodenum; Gastrointestinal Transit; Ileum; Inflammation Mediators; Insulin Resistance; Intestine, Small; Jejunum; Male; Myenteric Plexus; Rats, Wistar; Submucous Plexus; Rats
PubMed: 33580916
DOI: 10.14814/phy2.14755 -
World Journal of Gastroenterology Aug 2022The enteric nervous system (ENS) is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large...
BACKGROUND
The enteric nervous system (ENS) is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large intestines. The ENS consists of neurons, glial cells, and nerves assembled into ganglia, surrounded by telocytes, interstitial cells of Cajal, and connective tissue. Owing to the complex spatial organization of several interconnections with nerve fascicles, the ENS is difficult to examine in conventional histological sections of 3-5 μm.
AIM
To examine human ileum full-thickness biopsies using X-ray phase-contrast nanotomography without prior staining to visualize the ENS.
METHODS
Six patients were diagnosed with gastrointestinal dysmotility and neuropathy based on routine clinical and histopathological examinations. As controls, full-thickness biopsies were collected from healthy resection ileal regions after hemicolectomy for right colon malignancy. From the paraffin blocks, 4-µm thick sections were prepared and stained with hematoxylin and eosin for localization of the myenteric ganglia under a light microscope. A 1-mm punch biopsy (up to 1 cm in length) centered on the myenteric plexus was taken and placed into a Kapton tube for mounting in the subsequent investigation. X-ray phase-contrast tomography was performed using two custom-designed laboratory setups with micrometer resolution for overview scanning. Subsequently, selected regions of interest were scanned at a synchrotron-based end-station, and high-resolution slices were reported. In total, more than 6000 virtual slices were analyzed from nine samples.
RESULTS
In the overview scans, the general architecture and quality of the samples were studied, and the myenteric plexus was localized. High-resolution scans revealed details, including the ganglia, interganglional nerve fascicles, and surrounding tissue. The ganglia were irregular in shape and contained neurons and glial cells. Spindle-shaped cells with very thin cellular projections could be observed on the surface of the ganglia, which appeared to build a network. In the patients, there were no alterations in the general architecture of the myenteric ganglia. Nevertheless, several pathological changes were observed, including vacuolar degeneration, autophagic activity, the appearance of sequestosomes, chromatolysis, and apoptosis. Furthermore, possible expulsion of pyknotic neurons and defects in the covering cellular network could be observed in serial slices. These changes partly corresponded to previous light microscopy findings.
CONCLUSION
The analysis of serial virtual slices could provide new information that cannot be obtained by classical light microscopy. The advantages, disadvantages, and future possibilities of this method are also discussed.
Topics: Enteric Nervous System; Eosine Yellowish-(YS); Hematoxylin; Humans; Ileum; Myenteric Plexus; Paraffin; X-Rays
PubMed: 36157532
DOI: 10.3748/wjg.v28.i29.3994 -
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