Submucosal Plexus Research Articles

Hirschsprung's disease

Hirschsprung's disease (HD) or congenital aganglionic megacolon is characterized by an absence of ganglion cells in the myenteric Auerbach's plexus, the deep submucosal Henle's plexus, and the submucosal Meissner's plexus in the distal colon. The usual presentation of Hirschsprung's disease can be demonstrated by the following clinical scenario. A 3-day-old male presented with failure to pass meconium within 48 h of birth and progressive abdominal distension. Barium study showed dilated colon with no specific zone of transition. The newborn was delivered at 40 weeks gestation after an otherwise normal pregnancy. Transanal rectal biopsy demonstrated the absence of ganglion cells on multiple sections and special staining. The patient underwent an exploratory laparotomy, upon which he was found to have markedly dilated small bowel and colon up to the area of sigmoid. A transverse loop colostomy was performed. The patient recovered well from the initial surgery and underwent definitive surgical therapy of the HD at a later time. The following core competencies are addressed in this article: Medical knowledge, Patient care. Republished with permission from: Prabhakaran S. Absite corner: Hirschsprung's disease. OPUS 12 Scientist 2009; 3(3):44-46.

Chronic gastric impaction and dilatation in horses: Clinical signs, diagnosis, treatment options and pathologic findings – A case series

The aim of this study was to summarize and evaluate clinical appearance, laboratory parameters, special ancillary diagnostic tests, treatments and post-mortem pathological findings of chronic gastric impaction and dilatation in horses. Chronic gastric impaction and dilatation is a rare, progressive disease, which is usually detected in its advanced stage. Its aetiology has not yet been fully clarified. Acute primary gastric impaction (from excess volume intake) and secondary gastric impaction (from reflux from the small intestine) must be differentiated from chronic gastric impaction and dilatation. Suspected causes of chronic gastric impaction and dilatation include pyloric stenosis, gastric ulcers, gastric tumours, indigestible feed, feed with high fibre content and dental problems. Motility disorders with resulting gastric impaction and dilatation have also been described in the context of liver diseases. Additional theories suggest damage to the vagus nerve or the intramural nervous system of the stomach and aplasia of the autonomous ganglia of the myenteric and submucosal plexus. It is a retrospective case study of four cases of chronic gastric impaction and dilatation between 2010 and 2013 concerning clinical appearance, laboratory parameters, ancillary diagnostic tests, treatment options and post-mortem pathological findings. For comparison, an additional case of delayed gastric emptying with successful conservative treatment is presented. In one case, nerve degeneration was confirmed and could possibly explain the chronic gastric impaction. A recurrent finding was the adaptive enlargement of the stomach with significant thinning of the muscularis, which was evident in all cases. This is likely to be the result of chronic dilation with a gradually prolonged filling of the stomach leading to 'stretching' of the stomach wall and therefore also a loss of motility, which could be equated to dilated cardiomyopathy, where cardiac output volume decreases with dilation. Gross pathology revealed greatly enlarged stomachs with dry impacted feed material of 43 kg, 46 kg and 108 kg. The treatment options for the disease, whether conservative or surgical depend on the severity and cause of the gastric impaction, and are said to have a very poor or unfavourable prognosis. Chronic gastric impaction can lead to a rupture of the stomach and therefore the prognosis is generally suspected to be grave. Perhaps early identification of delayed gastric emptying and chronic gastric impaction via repetitive gastroscopy could allow for a more successful treatment.

Development of Calbindin- and Calretinin-Immunopositive Neurons in the Enteric Ganglia of Rats.

Calbindin D28K (CB) and calretinin (CR) are the members of the EF-hand family of calcium-binding proteins that are expressed in neurons and nerve fibers of the enteric nervous system. CB and CR are expressed differentially in neuronal subpopulations throughout the central and peripheral nervous systems and their expression has been used to selectively target specific cell types and isolate neuronal networks. The present study presents an immunohistochemical analysis of CB and CR in the enteric ganglia of small intestine in rats of different ages (newborn, 10-day-old, 20-day-old, 30-day-old, 60-day-old, 1-year-old, and 2-year-old). The data obtained suggest a number of age-dependent changes in CB and CR expression in the myenteric and submucous plexuses. In the myenteric plexus, the lowest percentage of CB-immunoreactive (IR) and CR-IR neurons was observed at birth, after which the number of IR cells increased in the first 10days of life. In the submucous plexus, CB-IR and CR-IR neurons were observed from 10-day-old onwards. The percentage of CR-IR and CB-IR neurons increased in the first 2 months and in the first 20days, respectively. In all animals, the majority of the IR neurons colocalized CR and CB. From the moment of birth, the mean of the cross-sectional area of the CB-IR and CR-IR neuronal profiles was larger than that of CB- and CR-negative cells.

Expressions of glial cell line-derived neurotrophic factor and its tyrosine kinase receptor RET in the terminal rectum of fetal rats with congenital anorectal malformations at different gestational ages

Objective To explore the expressions and distributions of glial cell line-derived neurotrophic factor (GDNF) and itstyrosine kinase receptor RET in the terminal rectums of fetal rats with congenital anorectal malformations (ARM) at different gestationalage, and to explore their effects on the enteric nervous system in the terminal rectum of ARM fetal rats. Methods Thirty-five SD pregnancy rats were divided into a saline group (n=10) and an ethylenethiourea experiment group (n=25) by simple randomized study.The fetal rats were removed from the pregnant rats at the gestational 16 d, 18 d and 20 d. The fetal rats were divided into the saline control group, the ethylenethiourea control group (fetal rats without ARM) and the ethylenethiourea malformation group (ARM fetal rats) by the naked eye and dissecting microscope.HE staining was used to observe the morphology and the intestinal ganglion cells in the terminal rectum were counted.The immunohistochemical staining and Western blot methods were used to observe the distributions of GDNF and RET in the rectum at the gestational 16 d, 18 d and 20 d. The quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of GDNF mRNA in the fetal rats in the terminal rectum at the gestational 16 d, 18 d and 20 d. Results HE staining: the development of anorectal terminal in 3 groups of fetal rats was unclear at the gestational 16 d. A small amount of scattered nerve plexuses were observed in the muscular layer.The nuclei were small and sparse.The axons and cytoplasms were less.The serosal layer, muscular layer, submucosa, mucosal layer and glands in the terminal rectum were gradually clear in the saline control group and the ethylenethiourea control group at the gestational 18 d and 20 d. The intermuscular submucosal nerve plexuses increased gra-dually (11.400±3.134 and 11.200±3.425 at the gestational 18 d; 66.100±4.954 and 67.600±5.481 at the gestational 20 d). While, the layer was unclear in the ethylenethiourea malformation group and the nerve plexus was less (7.800±1.989 at the gestational 18 d, and 25.200±3.048 at the gestational 20 d), and the difference was statistically significant compared with 2 control groups (F=7.591, 271.833, all P 0.05); the expressions of GDNF and RET protein were 103.624±27.533 and 105.184±19.634 at the gestational 18 d; 151.496±33.622 and 150.738±21.423 at the gestational 20 d in 2 control groups.Compared with the ethylenethiourea malformation group (79.169±11.697 at the gestational 18 d; 94.873±11.309 at the gestational 20 d), and the difference were statistically significant (all P<0.05). Conclusions The expressions of GDNF and its tyrosine kinase receptor RET had a certain temporal correlation in the terminal rectum of normal fetal rats at different gestational ages and ARM.Moreover, the abnormal expressions of GDNF and its tyrosine kinase receptor RET in the distal rectum of ARM fetal rats can affect the development of enteric nervous system. Key words: Glial cell line-derived neurotrophic factor; RET; Signal pathway; Enteric nervous system; Congenital anorectal malformation

Opioid-Induced Constipation: A Comprehensive Overview

In the United States, 4.3 million adults are regularly taking opioid medications. Opioid-induced constipation (OIC) is underdiagnosed considering the prevalence of opioid use among Americans. This review is intended to clarify issues related to OIC. OIC is caused by opioids binding to specific receptors in the gastrointestinal system, resulting in various anatomic effects, including decreased gastric motility, increased sphincter tone, reduced intestinal secretions, and increased water absorption in the bowel. Various treatments include water and fiber consumption, laxatives, enemas, cessation of opioids, and central and peripheral opioid antagonists. OIC is treatable, but timely diagnosis and patient education are paramount for successful resolution. Key words: chronic pain; constipation; mu, delta, and kappa receptors; myenteric plexus; opioid; opioid-induced constipation; opioid receptor antagonists; submucosal plexus

Engineered human pluripotent-stem-cell-derived intestinal tissues with a functional enteric nervous system.

The enteric nervous system (ENS) of the gastrointestinal tract controls many diverse functions, including motility and epithelial permeability. Perturbations in ENS development or function are common, yet there is no human model for studying ENS-intestinal biology and disease. We used a tissue-engineering approach with embryonic and induced pluripotent stem cells (PSCs) to generate human intestinal tissue containing a functional ENS. We recapitulated normal intestinal ENS development by combining human-PSC-derived neural crest cells (NCCs) and developing human intestinal organoids (HIOs). NCCs recombined with HIOs in vitro migrated into the mesenchyme, differentiated into neurons and glial cells and showed neuronal activity, as measured by rhythmic waves of calcium transients. ENS-containing HIOs grown in vivo formed neuroglial structures similar to a myenteric and submucosal plexus, had functional interstitial cells of Cajal and had an electromechanical coupling that regulated waves of propagating contraction. Finally, we used this system to investigate the cellular and molecular basis for Hirschsprung's disease caused by a mutation in the gene PHOX2B. This is, to the best of our knowledge, the first demonstration of human-PSC-derived intestinal tissue with a functional ENS and how this system can be used to study motility disorders of the human gastrointestinal tract.

Role of oxidative stress in oxaliplatin-induced enteric neuropathy and colonic dysmotility in mice.

Background and PurposeOxaliplatin is a platinum‐based chemotherapeutic drug used as a first‐line therapy for colorectal cancer. However, its use is associated with severe gastrointestinal side‐effects resulting in dose limitations and/or cessation of treatment. In this study, we tested whether oxidative stress, caused by chronic oxaliplatin treatment, induces enteric neuronal damage and colonic dysmotility.Experimental ApproachOxaliplatin (3 mg·kg−1 per day) was administered in vivo to Balb/c mice intraperitoneally three times a week. The distal colon was collected at day 14 of treatment. Immunohistochemistry was performed in wholemount preparations of submucosal and myenteric ganglia. Neuromuscular transmission was studied by intracellular electrophysiology. Circular muscle tone was studied by force transducers. Colon propulsive activity studied in organ bath experiments and faeces were collected to measure water content.Key ResultsChronic in vivo oxaliplatin treatment resulted in increased formation of reactive oxygen species (O2ˉ), nitration of proteins, mitochondrial membrane depolarisation resulting in the release of cytochrome c, loss of neurons, increased inducible NOS expression and apoptosis in both the submucosal and myenteric plexuses of the colon. Oxaliplatin treatment enhanced NO‐mediated inhibitory junction potentials and altered the response of circular muscles to the NO donor, sodium nitroprusside. It also reduced the frequency of colonic migrating motor complexes and decreased circular muscle tone, effects reversed by the NO synthase inhibitor, Nω‐Nitro‐L‐arginine.Conclusion and ImplicationsOur study is the first to provide evidence that oxidative stress is a key player in enteric neuropathy and colonic dysmotility leading to symptoms of chronic constipation observed in oxaliplatin‐treated mice.

A model of the enteric neural circuitry underlying the generation of rhythmic motor patterns in the colon: the role of serotonin.

We discuss the role of multiple cell types involved in rhythmic motor patterns in the large intestine that include tonic inhibition of the muscle layers interrupted by rhythmic colonic migrating motor complexes (CMMCs) and secretomotor activity. We propose a model that assumes these motor patterns are dependent on myenteric descending 5-hydroxytryptamine (5-HT, serotonin) interneurons. Asynchronous firing in 5-HT neurons excite inhibitory motor neurons (IMNs) to generate tonic inhibition occurring between CMMCs. IMNs release mainly nitric oxide (NO) to inhibit the muscle, intrinsic primary afferent neurons (IPANs), glial cells, and pacemaker myenteric pacemaker interstitial cells of Cajal (ICC-MY). Mucosal release of 5-HT from enterochromaffin (EC) cells excites the mucosal endings of IPANs that synapse with 5-HT descending interneurons and perhaps ascending interneurons, thereby coupling EC cell 5-HT to myenteric 5-HT neurons, synchronizing their activity. Synchronized 5-HT neurons generate a slow excitatory postsynaptic potential in IPANs via 5-HT7 receptors and excite glial cells and ascending excitatory nerve pathways that are normally inhibited by NO. Excited glial cells release prostaglandins to inhibit IMNs (disinhibition) to allow full excitation of ICC-MY and muscle by excitatory motor neurons (EMNs). EMNs release ACh and tachykinins to excite pacemaker ICC-MY and muscle, leading to the simultaneous contraction of both the longitudinal and circular muscle layers. Myenteric 5-HT neurons also project to the submucous plexus to couple motility with secretion, especially during a CMMC. Glial cells are necessary for switching between different colonic motor behaviors. This model emphasizes the importance of myenteric 5-HT neurons and the likely consequence of their coupling and uncoupling to mucosal 5-HT by IPANs during colonic motor behaviors.

A Retrospective Cohort Study of Total Colonic Aganglionosis: Is the Appendix a Reliable Diagnostic Tool?

Background: Hirschsprung's disease (HD) is characterized by a lack of ganglion cells in the myenteric and submucosal plexus, associated with increased numbers of acetyl cholinesterase (AChE) positive nerve fibres. In approximately 10% of patients with HD the entire colon will be affected; a condition known as Total Colonic Aganglionosis (TCA). Aganglionosis of the appendix has long been considered to be an important finding in a patient in whom TCA is suspected, but its reliability for diagnosis has seldom been discussed. The aim of our study was to assess the reliability of the appendix as a histological specimen for the diagnosis of TCA, and to evaluate the long-term outcome of TCA. Methods: A retrospective cohort study was performed of all pathological specimens of patients with confirmed HD in our institution between March 2006 and April 2016. Results: Out of a total of 91 patients identified, 15 patients also had histopathological analysis of the appendix. Nine of these cases were confirmed as having TCA. The remaining 6 patients had HD involving the rest of the bowel up to the ascending colon, with normal ganglion present in the caecum. The appendix was removed in all the 15 cases. All 9 patients with confirmed TCA had aganglionosis of the appendix as well. The remaining 6 cases of short and long segment HD not involving the caecum, demonstrated normal ganglion cells within the appendix. Conclusion: Aganglionosis of the appendix is a reliable tool in the diagnosis of TCA. The authors recommend that at the time of levelling biopsies, if aganglionosis extends to the mid-transverse colon, an ileostomy be performed and appendix sent for definitive confirmation of TCA. However, at the time of definitive surgery, a frozen section of pull-through segment of bowel is recommended to confirm the presence of ganglion cells.

Gastrointestinal Dysfunction and Neuropathologic Correlations in Parkinson Disease.

Recently, an increasing interest to nonmotor symptoms of Parkinson disease (PD) has shown. Gastrointestinal dysfunction is a prominent nonmotor manifestation of PD and precedes motor symptoms for several years. Neuropathologic studies show early accumulation of α-synuclein (α-SYN) in Lewy neurites and Lewy body in the enteric nervous system (ENS) and dorsal motor nucleus of the vagus in PD. Our study aims to investigate relationship between α-SYN deposition in ENS and gastrointestinal dysfunction in PD. We conducted a study in Neurology Department of Charles Nicolle Hospital of Tunis during 2 years (2013 to 2014) including PD patients. Clinical data were analyzed. Digestive endoscopy with biopsies of upper digestive tract (UDT) and immunohistochemistry study were performed. Thirty patients (16♂/14♀) and 13 (7♂/6♀) controls were included. Average age was 65 years for patients and 63.5 years for controls. Gastrointestinal symptoms were the most frequent nonmotor symptoms occurring in 73%. Endoscopy showed motor dysfunction of upper digestive tract in 5 patients. Lesion load in α-SYN was significantly correlated with frequency and severity of gastrointestinal dysfunction and PD motor disability. Gastrointestinal disturbances are frequent in PD. ENS's synucleinopathy could entirely explain pathophysiology of digestive dysfunction and is correlated with severity of gastrointestinal symptoms in PD. Biopsies may show α-SYN aggregates in immunoreactive Lewy neurites in the submucosal and myenteric plexus. Thus, endoscopic and immunohistochemical exploration of ENS may be a biomarker for Parkinson enteropathy and for PD overall.

Experimental Cancer Cachexia Changes Neuron Numbers and Peptide Levels in the Intestine: Partial Protective Effects after Dietary Supplementation with L-Glutamine

Gastrointestinal dysmotility frequently occurs in cancer cachexia and may result from damage to enteric innervation caused by oxidative stress, especially due to glutathione depletion. We assessed the effect of dietary supplementation with 20 g/kg l-glutamine (a glutathione precursor) on the intrinsic innervation of the enteric nervous system in healthy and Walker 256 tumor-bearing Wistar rats during the development of experimental cachexia (14 days), in comparison with non-supplemented rats, by using immunohistochemical methods and Western blotting. The total neural population and cholinergic subpopulation densities in the myenteric plexus, as well as the total population and VIPergic subpopulation in the submucosal plexus of the jejunum and ileum, were reduced in cachectic rats, resulting in adaptive morphometric alterations and an increase in vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) expression, suggesting a neuroplastic response. l-glutamine supplementation prevented decrease in myenteric neuronal density in the ileum, morphometric alterations in the neurons and nerve fibers (in both the plexuses of the jejunum and ileum), and the overexpression of VIP and CGRP. Cancer cachexia severely affected the intrinsic innervation of the jejunum and ileum to various degrees and this injury seems to be associated with adaptive neural plasticity. l-glutamine supplementation presented partial protective effects on the enteric innervation against cancer cachexia, possibly by attenuating oxidative stress.

Colorectal cancer patients exhibit increased levels of galanin in serum and colon tissues.

Galanin (GAL) is a 30-amino acid neuropeptide that is expressed in both the central and peripheral nervous system, including the enteric nervous system (ENS). Increased GAL concentrations have been identified in the blood of colorectal cancer (CRC) patients. The aim of the present study was to assess whether sections of the colon wall containing ENS plexuses or CRC tumor are associated with increased GAL concentrations. Blood samples were collected from 68 CRC patients and 39 healthy volunteers. In addition, samples of CRC tumors and colon wall tissue in close proximity to and distant from the neoplastic tissue were obtained from 22 CRC patients. The GAL concentration of sera and tissue homogenates obtained from three sections of the colon wall (mucosa with submucosa, muscularis externa and CRC tumor) was analyzed by ELISA. The localization of GAL was evaluated using immunohistochemistry and morphometry was used to measure the distribution of GAL-immunoreactive (GAL-Ir) myenteric plexuses in the vicinity of cancer invasion and in sections of the colon wall distant from the tumor. The GAL serum concentration of CRC patients was 2.4 times higher than that of the control group. The GAL concentration was highest in the homogenates of neoplastic tissue and mucosa obtained from the control (distant) section of the intestinal wall, followed by that in the mucosa and muscularis externa proximal to the tumor. The lowest GAL concentrations were identified within the muscular layer of the colon wall located distant from the tumor. Strong GAL immunoreactivity was identified in the cancer cells, intestinal epithelium and the submucosal and myenteric plexuses. Morphometric analysis revealed that the GAL-Ir myenteric plexuses in the vicinity of tumor infiltration were significantly smaller in size than those in the intact section of the large intestine. Furthermore, no associations were identified between the clinicopathological characteristics of CRC patients and GAL serum and tissue concentration. The increased GAL serum concentrations observed in CRC patients in comparison to healthy controls may result from GAL secretion by CRC tumors, however, other sources of GAL cannot be excluded. The atrophy of myenteric plexuses within close proximity to the tumor may affect the colon function of CRC patients. In conclusion, investigation into the presence of GAL in the colon wall and serum of CRC patients revealed that serum and tissue GAL levels may present useful potential biomarkers in CRC patients.

Epithelial propionyl- and butyrylcholine as novel regulators of colonic ion transport.

The colonic surface epithelium produces acetylcholine, released after the binding of propionate to GPCRs for this short-chain fatty acid (SCFA). This epithelial acetylcholine then induces anion secretion via stimulation of acetylcholine receptors. The key enzyme responsible for acetylcholine synthesis, choline acetyltransferase, is known to be unselective as regards the fatty acid used for esterification of choline. As the colonic epithelium is permanently exposed to high concentrations of different SCFAs produced by bacterial fermentation, we investigated whether choline esters other than acetylcholine, propionylcholine and butyrylcholine, are produced by the colonic epithelium, too, and whether these 'atypical' esters are able to stimulate the acetylcholine receptors involved in the regulation of colonic ion transport. Desorption electrospray ionization mass spectroscopy (DESI-MS), Ussing chamber and Ca(2+) -imaging experiments were performed on rat distal colon. DESI-MS analyses revealed the production of acetylcholine, propionylcholine and butyrylcholine in the surface epithelium. Relative expression rates were 2-3% in comparison with acetylcholine. In Ussing chamber experiments, both atypical choline esters caused a concentration-dependent increase in short-circuit current, that is, stimulated anion secretion. Inhibitor experiments in the absence and presence of the submucosal plexus revealed the involvement of neuronal and epithelial acetylcholine receptors. While butyrylcholine obviously stimulated both nicotinic and muscarinic receptors, propionylcholine predominantly acted on muscarinic receptors. These results suggest a novel pathway for communication between intestinal microbes producing SCFA and the host via modification of epithelial production of choline esters involved in the paracrine regulation of the colonic epithelium.

Regenerative Capacity of the Enteric Nervous System after Ileoileal Anastomoses in a Rat Model.

Purpose The aim of the study was to investigate the regeneration and migration of neuronal progenitor cells of the enteric nervous system during wound healing after intestinal anastomosis in the rat ileum. Methods Experiments were performed in a rat model of ileoileal anastomosis. Rats were humanely killed on day 2 or day 10 after anastomosis, and the anastomotic region was compared with ileum of healthy rats. Immunofluorescent staining was performed with protein gene product 9.5, nestin, and S100 antibodies. Ganglia of the anastomotic region in both the myenteric and submucosal plexus were counted, and their diameters were measured and compared between groups. Results Analysis of number and diameter of ganglia in both myenteric and submucosal plexus showed individual alterations as a reaction to the surgical manipulation. Significantly less ganglia were found in the submucosal plexus in the operated groups at both day 2 (p < 0.01) and day 10 (p < 0.01) than in the control group. In the myenteric plexus in the operated group, there was a difference in the number of ganglia at day 2, but ganglia count had recovered at day 10 and was not significantly different from the control group. However, the diameter of ganglia in the myenteric plexus still significantly decreasing on day 10 after surgery than in the control group (p = 0.046). Nestin and S100 double-staining showed an increased expression of nestin around the anastomotic wound. Conclusion Our findings suggest a regenerative potential of the enteric nervous system after the surgical ileoileal anastomosis. The myenteric plexus appears to recover faster than the submucosal plexus. This recovery might be driven by nestin-positive neuronal progenitor cells.

Submucosal Plexitis as a Predictive Factor for Postoperative Endoscopic Recurrence in Patients with Crohn's Disease Undergoing a Resection with Ileocolonic Anastomosis: Results from a Prospective Single-centre Study.

Ileocolonoscopy allows early detection of recurrence after surgical resection for Crohn's disease [CD]. Plexitis, defined as presence of inflammatory cells in or around enteric ganglia or nerve bundles, in the proximal surgical margin has been associated with an increased overall recurrence risk. We investigated prospectively whether plexitis can predict endoscopic recurrence [ER] in a consecutive cohort of CD patients undergoing ileocolonic resection. All CD patients undergoing ileocolonic resection in our institution between October 2009 and December 2012 were eligible for this study. Clinical data were obtained prospectively from the patients' files, and biopsies from the proximal surgical margins were analysed immunohistochemically for inflammation at the myenteric and submucosal plexus [lymphocytes, mast cells, eosinophils]. The degree of plexitis was correlated with the presence of ER at 6 months, defined as a modified Rutgeerts' score of ≥ i2b. Multivariate models were developed and tested to predict posterior probability of ER. A total of 74 patients were included. Six months after ileocolonic resection, 50% showed ER. Known risk factors such as penetrating disease, previous resections, and active smoking, showed no relation with ER. On the other hand, submucosal lymphocytic plexitis was associated with ER [p = 0.020]. The predictive value of lymphocytic cell count increased with more extensive biopsy sampling and with application of immunohistochemistry. Submucosal lymphocytic plexitis in the proximal surgical margin was significantly related with a higher risk for ER after ileocolonic resection. These data support development of a postoperative prevention trial with vedolizumab, which may block lymphocytic trafficking in the postoperative bowel.

Effects of Oxaliplatin Treatment on the Enteric Glial Cells and Neurons in the Mouse Ileum.

Oxaliplatin, currently used for treatment of colorectal and other cancers, causes severe gastrointestinal side effects, including nausea, vomiting, diarrhea, and constipation that are attributed to mucosal damage. However, delayed onset and long-term persistence of these side effects suggest that damage to the enteric nervous system (ENS) regulating physiological function of the gastrointestinal tract may also occur. The ENS comprises myenteric and submucosal neurons and enteric glial cells (EGCs). This study aimed to investigate the effects of oxaliplatin treatment on enteric neurons and EGCs within the mouse ileum. BALB/c mice received repeated intraperitoneal injections of oxaliplatin (3 mg/kg, 3 injections/week). Tissues were collected 3, 7, 14, and 21 days from the commencement of treatment. Decreases in glial fibrillary acidic protein-immunoreactive (IR) EGCs and protein gene product 9.5/β-Tubulin III-IR neurons as well as increase in s100β-IR EGCs after chronic oxaliplatin administration were observed in both the myenteric and submucosal plexi. Changes in EGCs were further observed in cross-sections of the ileum at day 14 and confirmed by Western blotting. Alterations in EGCs correlated with loss of myenteric and submucosal neurons in the ileum from oxaliplatin-treated mice. These changes to the ENS may contribute to the mechanisms underlying gastrointestinal side effects associated with oxaliplatin treatment.

Distribution and trafficking of the μ-opioid receptor in enteric neurons of the guinea pig.

The μ-opioid receptor (MOR) is a major regulator of gastrointestinal motility and secretion and mediates opiate-induced bowel dysfunction. Although MOR is of physiological and therapeutic importance to gut function, the cellular and subcellular distribution and regulation of MOR within the enteric nervous system are largely undefined. Herein, we defined the neurochemical coding of MOR-expressing neurons in the guinea pig gut and examined the effects of opioids on MOR trafficking and regulation. MOR expression was restricted to subsets of enteric neurons. In the stomach MOR was mainly localized to nitrergic neurons (∼88%), with some overlap with neuropeptide Y (NPY) and no expression by cholinergic neurons. These neurons are likely to have inhibitory motor and secretomotor functions. MOR was restricted to noncholinergic secretomotor neurons (VIP-positive) of the ileum and distal colon submucosal plexus. MOR was mainly detected in nitrergic neurons of the colon (nitric oxide synthase positive, 87%), with some overlap with choline acetyltransferase (ChAT). No expression of MOR by intrinsic sensory neurons was detected. [d-Ala(2), MePhe(4), Gly(ol)(5)]enkephalin (DAMGO), morphiceptin, and loperamide induced MOR endocytosis in myenteric neurons. After stimulation with DAMGO and morphiceptin, MOR recycled, whereas MOR was retained within endosomes following loperamide treatment. Herkinorin or the δ-opioid receptor agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) did not evoke MOR endocytosis. In summary, we have identified the neurochemical coding of MOR-positive enteric neurons and have demonstrated differential trafficking of MOR in these neurons in response to established and putative MOR agonists.

Contralateral neck dissection in oral squamous cell carcinoma: when it shoud be done?

Oral cavity squamous cell carcinoma (OSCC) has a high incidence of cervical micrometastases and sometimes metastasizes bilaterally because of the rich lymphatics in the submucosal plexus, which freely communicate across the midline. The presence of contralateral pathologic lymph nodes has been reported previously as a critical factor influencing the survival of patients. There are a few reports in the literature with regard to the rates of contralateral neck disease and the factors that may be involved in the risk with them. An elective ipsilateral neck treatment is generally recommended for initial treatment in all OSCC. However, no consensus exists whether or not to perform an elective contralateral neck dissection or radiation. In this study, a systematic review has been performed in order to evaluate the predictive value of clinical-histopathologic factors potentially related to contralateral occult lymph node metastasis in squamous cell carcinomas of the oral cavity to form a rational basis for elective contralateral neck management.

Nanoscale titania takes scientists closer to sustainable hydrogen production

Parkinson's disease is the second most common neurodegenerative disorder, affecting 1–2% of the population over 65 years of age. The primary neuropathology is the loss of midbrain dopaminergic neurons, resulting in characteristic motor deficits, upon which the clinical diagnosis is based. However, a number of significant non-motor symptoms (NMS) are also evident that appear to have a greater impact on the quality of life of these patients.In recent years, it has become increasingly apparent that neurobiological processes can be modified by the bi-directional communication that occurs along the brain-gut axis. The microbiota plays a key role in this communication throughout different routes in both physiological and pathological conditions. Thus, there has been an increasing interest in investigating how microbiota changes within the gastrointestinal tract may be implicated in health and disease including PD.Interestingly α-synuclein-aggregates, the cardinal neuropathological feature in PD, are present in both the submucosal and myenteric plexuses of the enteric nervous system, prior to their appearance in the brain, indicating a possible gut to brain route of “prion-like” spread. In this review we highlight the potential importance of gut to brain signalling in PD with particular focus on the role of the microbiota as major player in this communication.

Decreased Nav1.9 channel expression in Hirschsprung's disease

AimVoltage-gated sodium channel subtype 9 (Nav1.9) are expressed in dorsal root ganglion neurons and are known to be involved in pain during inflammation. Animal studies have reported Nav1.9 channel expression in myenteric intrinsic primary afferent neurons (IPANs). More recently, a study involving Nav1.9 knockout mice showed clear evidence of colonic dysmotility. However, there are no data regarding the expression of these channels in the human intestine, thus, the aim of our study was to determine Nav1.9 channel expression within the human colon and to elucidate if Nav1.9 channel expression is altered in Hirschsprung's disease (HD). MethodsHD tissue specimens (n=10) were collected at the time of pull-through surgery, while normal controls were obtained at the time of colostomy closure in patients with imperforate anus (n=10). Nav1.9 immunofluorescence was visualized using confocal microscopy to assess the distribution of the protein. Western blot analysis was undertaken to determine Nav1.9 protein quantification. ResultsConfocal microscopy revealed Nav1.9-immunoreactive neurons within the submucosal and myenteric plexus in normal controls, with a reduction in the HD specimens. Calbindin double-labeling showed that Nav1.9-immunoreactive neurons were IPANs. Nav1.9 channels were also seen to be co-localized on smooth muscle cells in all tissues. Western blotting revealed high levels of Nav1.9 protein expression in normal controls, while there was a marked decrease in Nav1.9 protein expression in the HD tissue. ConclusionOur results show the expression of Nav1.9 channels within the human colon for the first time. Furthermore, Nav1.9 channel expression is decreased in HD versus normal controls.