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Histochemistry and Cell Biology Nov 2023Short bowel syndrome (SBS) is a severe, life-threatening condition and one of the leading causes of intestinal failure in children. Here we were interested in changes in...
Short bowel syndrome (SBS) is a severe, life-threatening condition and one of the leading causes of intestinal failure in children. Here we were interested in changes in muscle layers and especially in the myenteric plexus of the enteric nervous system (ENS) of the small bowel in the context of intestinal adaptation. Twelve rats underwent a massive resection of the small intestine to induce SBS. Sham laparotomy without small bowel transection was performed in 10 rats. Two weeks after surgery, the remaining jejunum and ileum were harvested and studied. Samples of human small bowel were obtained from patients who underwent resection of small bowel segments due to a medical indication. Morphological changes in the muscle layers and the expression of nestin, a marker for neuronal plasticity, were studied. Following SBS, muscle tissue increases significantly in both parts of the small bowel, i.e., jejunum and ileum. The leading pathophysiological mechanism of these changes is hypertrophy. Additionally, we observed an increased nestin expression in the myenteric plexus in the remaining bowel with SBS. Our human data also showed that in patients with SBS, the proportion of stem cells in the myenteric plexus had risen by more than twofold. Our findings suggest that the ENS is tightly connected to changes in intestinal muscle layers and is critically involved in the process of intestinal adaptation to SBS.
Topics: Child; Rats; Humans; Animals; Short Bowel Syndrome; Nestin; Rats, Sprague-Dawley; Ileum; Disease Models, Animal; Neuronal Plasticity
PubMed: 37395792
DOI: 10.1007/s00418-023-02214-4 -
Cellular and Molecular Gastroenterology... 2023Gut functions including motility, secretion, and blood flow are largely controlled by the enteric nervous system. Characterizing the different classes of enteric neurons...
BACKGROUND AND AIMS
Gut functions including motility, secretion, and blood flow are largely controlled by the enteric nervous system. Characterizing the different classes of enteric neurons in the human gut is an important step to understand how its circuitry is organized and how it is affected by disease.
METHODS
Using multiplexed immunohistochemistry, 12 discriminating antisera were applied to distinguish different classes of myenteric neurons in the human colon (2596 neurons, 12 patients) according to their chemical coding. All antisera were applied to every neuron, in multiple layers, separated by elutions.
RESULTS
A total of 164 combinations of immunohistochemical markers were present among the 2596 neurons, which could be divided into 20 classes, with statistical validation. Putative functions were ascribed for 4 classes of putative excitatory motor neurons (EMN1-4), 4 inhibitory motor neurons (IMN1-4), 3 ascending interneurons (AIN1-3), 6 descending interneurons (DIN1-6), 2 classes of multiaxonal sensory neurons (SN1-2), and a small, miscellaneous group (1.8% of total). Soma-dendritic morphology was analyzed, revealing 5 common shapes distributed differentially between the 20 classes. Distinctive baskets of axonal varicosities surrounded 45% of myenteric nerve cell bodies and were associated with close appositions, suggesting possible connectivity. Baskets of cholinergic terminals and several other types of baskets selectively targeted ascending interneurons and excitatory motor neurons but were significantly sparser around inhibitory motor neurons.
CONCLUSIONS
Using a simple immunohistochemical method, human myenteric neurons were shown to comprise multiple classes based on chemical coding and morphology and dense clusters of axonal varicosities were selectively associated with some classes.
Topics: Humans; Myenteric Plexus; Enteric Nervous System; Neurons, Afferent; Motor Neurons; Colon
PubMed: 37355216
DOI: 10.1016/j.jcmgh.2023.06.010 -
Frontiers in Neuroanatomy 2023The distribution, morphology, and innervation of vasculature in different mouse colonic segments and layers, as well as spatial relationships of the vasculature with the...
The distribution, morphology, and innervation of vasculature in different mouse colonic segments and layers, as well as spatial relationships of the vasculature with the enteric plexuses, glia, and macrophages are far from being complete. The vessels in the adult mouse colon were stained by the cardiovascular perfusion of wheat germ agglutinin (WGA)-Alexa Fluor 448 and by CD31 immunoreactivity. Nerve fibers, enteric glia, and macrophages were immunostained in the WGA-perfused colon. The blood vessels entered from the mesentery to the submucosa and branched into the capillary networks in the mucosa and muscularis externa. The capillary net formed anastomosed rings at the orifices of mucosa crypts, and the capillary rings surrounded the crypts individually in the proximal colon and more than two crypts in the distal colon. Microvessels in the muscularis externa with myenteric plexus were less dense than in the mucosa and formed loops. In the circular smooth muscle layer, microvessels were distributed in the proximal, but not the distal colon. Capillaries did not enter the enteric ganglia. There were no significant differences in microvascular volume per tissue volume between the proximal and distal colon either in the mucosa or muscularis externa containing the myenteric plexus. PGP9.5-, tyrosine hydroxylase-, and calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers were distributed along the vessels in the submucosa. In the mucosa, PGP9.5-, CGRP-, and vasoactive intestinal peptide (VIP)-immunoreactive nerves terminated close to the capillary rings, while cells and processes labeled by S100B and glial fibrillary acidic protein were distributed mainly in the lamina propria and lower portion of the mucosa. Dense Iba1 immunoreactive macrophages were closely adjacent to the mucosal capillary rings. There were a few macrophages, but no glia in apposition to microvessels in the submucosa and muscularis externa. In conclusion, in the mouse colon, (1) the differences in vasculature between the proximal and distal colon were associated with the morphology, but not the microvascular amount per tissue volume in the mucosa and muscle layers; (2) the colonic mucosa contained significantly more microvessels than the muscularis externa; and (3) there were more CGRP and VIP nerve fibers found close to microvessels in the mucosa and submucosa than in the muscle layers.
PubMed: 37332321
DOI: 10.3389/fnana.2023.1130169 -
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 -
Gastro Hep Advances 2023Smooth muscle cells (SMCs), interstitial cells of Cajal (ICCs), and platelet-derived growth factor receptor alpha (PDGFR+) cells (PCs) form a functional syncytium in the...
Single Nucleus Sequencing of Human Colon Myenteric Plexus-Associated Visceral Smooth Muscle Cells, Platelet Derived Growth Factor Receptor Alpha Cells, and Interstitial Cells of Cajal.
BACKGROUND AND AIMS
Smooth muscle cells (SMCs), interstitial cells of Cajal (ICCs), and platelet-derived growth factor receptor alpha (PDGFR+) cells (PCs) form a functional syncytium in the bowel known as the "SIP syncytium." The SIP syncytium works in concert with the enteric nervous system (ENS) to coordinate bowel motility. However, our understanding of individual cell types that form this syncytium and how they interact with each other remains limited, with no prior single-cell RNAseq analyses focused on human SIP syncytium cells.
METHODS
We analyzed single-nucleus RNA sequencing data from 10,749 human colon SIP syncytium cells (5572 SMC, 372 ICC, and 4805 PC nuclei) derived from 15 individuals.
RESULTS
Consistent with critical contractile and pacemaker functions and with known enteric nervous system interactions, SIP syncytium cell types express many ion channels, including mechanosensitive channels in ICCs and PCs. PCs also prominently express extracellular matrix-associated genes and the inhibitory neurotransmitter receptor for vasoactive intestinal peptide (), a novel finding. We identified 2 PC clusters that differ in the expression of many ion channels and transcriptional regulators. Interestingly, SIP syncytium cells co-express 6 transcription factors (, , , , , and ) that may be part of a combinatorial signature that specifies these cells. Bowel region-specific differences in SIP syncytium gene expression may correlate with regional differences in function, with right (ascending) colon SMCs and PCs expressing more transcriptional regulators and ion channels than SMCs and PCs in left (sigmoid) colon.
CONCLUSION
These studies provide new insights into SIP syncytium biology that may be valuable for understanding bowel motility disorders and lead to future investigation of highlighted genes and pathways.
PubMed: 37206377
DOI: 10.1016/j.gastha.2022.12.004 -
Cells Apr 2023The enteric nervous system (ENS) is an intrinsic network of neuronal ganglia in the intestinal tube with about 100 million neurons located in the myenteric plexus and...
The enteric nervous system (ENS) is an intrinsic network of neuronal ganglia in the intestinal tube with about 100 million neurons located in the myenteric plexus and submucosal plexus. These neurons being affected in neurodegenerative diseases, such as Parkinson's disease, before pathological changes in the central nervous system (CNS) become detectable is currently a subject of discussion. Understanding how to protect these neurons is, therefore, particularly important. Since it has already been shown that the neurosteroid progesterone mediates neuroprotective effects in the CNS and PNS, it is now equally important to see whether progesterone has similar effects in the ENS. For this purpose, the RT-qPCR analyses of laser microdissected ENS neurons were performed, showing for the first time the expression of the different progesterone receptors (PR-A/B; mPRa, mPRb, PGRMC1) in rats at different developmental stages. This was also confirmed in ENS ganglia using immunofluorescence techniques and confocal laser scanning microscopy. To analyze the potential neuroprotective effects of progesterone in the ENS, we stressed dissociated ENS cells with rotenone to induce damage typical of Parkinson's disease. The potential neuroprotective effects of progesterone were then analyzed in this system. Treatment of cultured ENS neurons with progesterone reduced cell death by 45%, underscoring the tremendous neuroprotective potential of progesterone in the ENS. The additional administration of the PGRMC1 antagonist AG205 abolished the observed effect, indicating the crucial role of PGRMC1 with regard to the neuroprotective effect of progesterone.
Topics: Rats; Animals; Progesterone; Parkinson Disease; Neuroprotective Agents; Enteric Nervous System; Intestines
PubMed: 37190115
DOI: 10.3390/cells12081206 -
Current Issues in Molecular Biology Apr 2023The enteric nervous system (ENS) is organized into two plexuses-submucosal and myenteric-which regulate smooth muscle contraction, secretion, and blood flow along the... (Review)
Review
The enteric nervous system (ENS) is organized into two plexuses-submucosal and myenteric-which regulate smooth muscle contraction, secretion, and blood flow along the gastrointestinal tract under the influence of the rest of the autonomic nervous system (ANS). Interstitial cells of Cajal (ICCs) are mainly located in the submucosa between the two muscle layers and at the intramuscular level. They communicate with neurons of the enteric nerve plexuses and smooth muscle fibers and generate slow waves that contribute to the control of gastrointestinal motility. They are also involved in enteric neurotransmission and exhibit mechanoreceptor activity. A close relationship appears to exist between oxidative stress and gastrointestinal diseases, in which ICCs can play a prominent role. Thus, gastrointestinal motility disorders in patients with neurological diseases may have a common ENS and central nervous system (CNS) nexus. In fact, the deleterious effects of free radicals could affect the fine interactions between ICCs and the ENS, as well as between the ENS and the CNS. In this review, we discuss possible disturbances in enteric neurotransmission and ICC function that may cause anomalous motility in the gut.
PubMed: 37185756
DOI: 10.3390/cimb45040232 -
Saudi Pharmaceutical Journal : SPJ :... Mar 2023It has been reported diabetic gastroparesis is related to diabetic autonomic neuropathy of the gastrointestinal tract, and berberine (BBR) could ameliorate diabetic...
BACKGROUND
It has been reported diabetic gastroparesis is related to diabetic autonomic neuropathy of the gastrointestinal tract, and berberine (BBR) could ameliorate diabetic central and peripheral neuropathy. However, the influence of BBR on the function and motility of the gastric fundus nerve is unclear.
METHODS
A diabetic rat model was constructed, and HE staining was used to observe the morphological changes in the gastric fundus. The changes in cholinergic and nitrogen-related neurochemical indexes and the effects of BBR on them were measured using Elisa. The effects of BBR on the neural function and motility of gastric fundus were investigated by electric field stimulation (EFS) induced neurogenic response in vitro.
RESULTS
In the early stage of STZ-induced diabetic rats, the contractile response of gastric fundus induced by EFS was disorder, disturbance of contraction amplitude, and the cell bodies of neurons in the myenteric plexus of gastric fundus presented vacuolar lesions. Administration with BBR could improve the above symptoms. BBR further enhanced the contraction response in the presence of a NOS inhibitor or the case of inhibitory neurotransmitters removal. Interestingly, the activity of ACh could affect NO release directly and the enhancement of BBR on contractile response was canceled by calcium channel blockers completely.
CONCLUSIONS
In the early stage of STZ-induced diabetic rats, the neurogenic contractile response disorder of the gastric fundus is mainly related to cholinergic and nitrergic nerve dysfunction. BBR promotes the release of ACh mainly by affecting the calcium channel to improve the neurological dysfunction of the gastric fundus.
PubMed: 37026044
DOI: 10.1016/j.jsps.2023.01.010