Abnormal colonic interstitial cells of Cajal in children with anorectal malformations

Interstitial Cells of Cajal and Ganglion Cell Distribution in Sigmoid Stomal Limbs and Distal Rectum after Stoma Formation in Male Anorectal Malformation Patients Undergoing Staged Repair

Introduction

This study was undertaken to assess the distribution of ganglion cells (GCs) and interstitial cells of Cajal (ICCs) across different points of distal rectal pouch in anorectal malformation (ARM) patients over the three stages of repair. We hypothesize that along with the surgical factors, there could be intrinsic factors as well which can be the cause of dysmotility in these patients after surgical repair.

Methodology

Full-thickness colonic biopsy specimens were taken from the proximal stoma, distal stoma, and distal rectal pouch of 21 boys aged 0-8 months undergoing 3 staged repair of ARM at our tertiary care center between August 2022 and December 2023. There was an interstage interval of approximately 12-14 weeks. All underwent high-divided sigmoid colostomy in stage 1. Biopsy specimens for GC and ICC number were routinely processed, and immunohistochemistry was done for CD117. The data was assessed and compared with respect to location and stage of surgery.

Results

Both GC and ICC showed a gradual decrease in mean number over three stages for both proximal and distal ends of colostomy. For proximal stoma, the distribution of either cell type did not differ across the stages, but for distal stoma, the number of cells was significantly lower in the second stage (following colostomy, before posterior sagittal anorectoplasty). However, no difference was noted between the second and third stages. This indicates that factors during/just after colostomy itself must be responsible for decrease in ICC/GC.

Conclusion

Lesser number of GC and/or ICC in the distal pouch from stage 2 onward may point toward its association with projected hypomotility in ARM patients. Apart from innate distribution, we also infer that this could be consequent to vascular insult which may occur at the time of divided colostomy. Loop stoma may be a better alternative as vascularity is uninterrupted in loop colostomy.

The Effect of Shaoyao Gancao Decoction on Sphincter of Oddi Dysfunction in Hypercholesterolemic Rabbits via Protecting the Enteric Nervous System-Interstitial Cells of Cajal-Smooth Muscle Cells Network

Objective

This study observes the morphological changes in the enteric nervous system (ENS) – interstitial cells of Cajal (ICC) – smooth muscle cells (SMC) network in sphincter of Oddi dysfunction (SOD) in hypercholesterolemic rabbits following treatment with Shaoyao Gancao decoction (SGD), as well as the apoptosis of the ICC.

Methods

In this study, 48 healthy adult New Zealand rabbits are randomly divided into three groups (n = 16 in each group): the control, the model, and the SGD treatment groups. The hypercholesterolemic rabbit model is established. Hematoxylin and eosin staining, transmission electron microscopy, immunofluorescence, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, immunohistochemistry, Western blot analysis, and reverse transcription-polymerase chain reaction are used to detect the morphological changes in the ENS–ICC–SMC network, the expression of apoptosis-related proteins in the ICC, and to observe the curative effect of SGD after treatment.

Results

Compared with the control group, the morphology and the ultrastructure of the SO are destroyed in the model group. In addition, the protein gene product 9.5 (PGP9.5), nitric oxide (NO), the SMCs, and the ICC all significantly decreased while substance P (SP) significantly increased. Compared with the model group, the SO morphology and ultrastructure are repaired in the SGD group. In addition, the PGP9.5, NO, the SMCs, and the ICC significantly increased while SP decreased. In addition, SGD may activate the stem cell factor (SCF)/c-Kit signaling pathway to treat SO dysfunction by up-regulating the expression of c-Kit and SCF. Similarly, this pathway restores SO by up-regulating the expression of Bcl2 and inhibiting cleaved caspase-3, Bax, and the tumor necrosis factor.

Conclusion

Shaoyao Gancao decoction can promote the recovery of sphincter of Oddi dysfunction in hypercholesterolemic rabbits by protecting the ENS–ICC–SMC network.

Histopathologic and immunohistochemical findings in congenital anorectal malformations

It remains controversial whether the distal rectal pouch should be either resected or used for reconstruction in anorectoplasty for the treatment of anorectal malformations (ARMs). Hence the aim of this study was to investigate whether ARMs were associated with a global neuromuscular maldevelopment of the terminal rectum specimens.There were 36 cases of ARMs (25 recto-bulbar fistula and 11 recto-prostatic fistula) and 10 healthy controls. The hematoxylin and eosin and Masson trichrome stain were used to conduct the histologic examination. The immunohistochemistry (IHC) and Western blot were conducted to analyze the neuron-specific enolase (NSE), S-100 protein, interstitial cells of Cajal marker (C-kit) within the rectal specimens in control group and ARM group.The most frequently observed histologic findings in mucosa were inflammation, congestion, eroded, and hemorrhage in the ARM cases. Submucosal inflammation and congestion were the most common submucosal findings in the ARM cases. Disrupted muscularis propria was observed in 60% of ARM cases. Mature ganglionic cells were reduced and muscularis propria showed reduced and patchy positivity for NSE, S-100, and C-kit protein in ARM group compared to that in control group according to IHC. Western blotting showed the expression levels of NSE, S-100, and C-kit were lower in the ARM group than that in the control group (P < .01).Histopathologic and IHC findings suggest that the distal rectal pouch has distinct defects in the neuromusculature. So it suggested that ARMs are abnormally developed tissue and need to be resected for better functional outcomes of the remaining gut.

Motility disorders in infants

Gastrointestinal motility disorders are common in the pediatric population and may affect the entire gastrointestinal tract and can vary from mild to severe conditions. They may clinically manifest as gastro-esophageal reflux symptoms, feeding difficulties and failure to thrive, constipation and diarrhea amongst others. This review first highlights the embryologic development of the gastrointestinal tract, after which the prenatal and neonatal development of gastrointestinal motility is discussed. Normal motility patterns as seen in (preterm) infants are described as a background for the discussion of the most common congenital and acquired motility disorders in infancy. This review specifically focuses on the role of preterm birth on the development of these disorders.

Anorectal Malformations: Histomorphological and Immunohistochemical Evaluation of Neuronal Dysfunction

Objective :

The patients with anorectal malformations (ARM) have been identified with specific and non-specific pathological changes. The present study was conducted with the aim to study histomorphological changes and various immunohistochemical (IHC) markers (calretinin, S-100, CD117) in intestinal wall specimens to assess neuronal dysfunction in ARM patients.

Material and methods :

Thirty children having ARM were included in our study. In all the cases, a representative biopsy was received. The tissue sections were processed and wax blocks were prepared. Various histopathological changes were examined on routine H&E. Representative sections were further subjected to IHC staining for ganglion cells (calretinin), interstitial cells of Cajal (CD117) and nerve bundles (S-100 protein). Descriptive variables were analyzed to assess neuronal dysfunction in cases of ARM. Chi-square was used to compare the categorical values. P-value <0.05 was accepted as statistically significant.

Results :

Biopsies were studied for histological changes using H&E stain. The most frequently observed histological finding in mucosa was inflammation and congestion in 87% and 67% of cases respectively. Disrupted muscularis mucosa was observed in 60%, eroded mucosa in 57%, and hemorrhage in 40% of cases. Submucosal inflammation and congestion were most common finding observed in submucosa in 87% and 80% cases respectively. CD117 was used to demonstrate altered density and distribution of interstitial cells of Cajal (ICC) in cases of ARM. Majority of them belong to grade 2+ category (n=17, 57%) followed by grade 1+ (n=8, 17%) for ICC cells. Altered density and distribution of ICC was observed in ARM which was statistically significant (p=0.02).

Conclusion :

The malformed segments in ARM show various specific and non-specific histomorphological changes. Examination of H&E sections along with IHC stains evaluation can minimize need for repeated biopsies and unnecessary radical treatment. CD117 immunohistochemistry is reliable adjunctive test in evaluation of ICC in motility disorders of bowel. Calretinin is good marker for identification of ganglion cells. In ARM, density and distribution of ICCs is significantly altered which can explain postoperative dysmotility.

Mechanisms of Electrical Activation and Conduction in the Gastrointestinal System: Lessons from Cardiac Electrophysiology

The gastrointestinal (GI) tract is an electrically excitable organ system containing multiple cell types, which coordinate electrical activity propagating through this tract. Disruption in its normal electrophysiology is observed in a number of GI motility disorders. However, this is not well characterized and the field of GI electrophysiology is much less developed compared to the cardiac field. The aim of this article is to use the established knowledge of cardiac electrophysiology to shed light on the mechanisms of electrical activation and propagation along the GI tract, and how abnormalities in these processes lead to motility disorders and suggest better treatment options based on this improved understanding. In the first part of the article, the ionic contributions to the generation of GI slow wave and the cardiac action potential (AP) are reviewed. Propagation of these electrical signals can be described by the core conductor theory in both systems. However, specifically for the GI tract, the following unique properties are observed: changes in slow wave frequency along its length, periods of quiescence, synchronization in short distances and desynchronization over long distances. These are best described by a coupled oscillator theory. Other differences include the diminished role of gap junctions in mediating this conduction in the GI tract compared to the heart. The electrophysiology of conditions such as gastroesophageal reflux disease and gastroparesis, and functional problems such as irritable bowel syndrome are discussed in detail, with reference to ion channel abnormalities and potential therapeutic targets. A deeper understanding of the molecular basis and physiological mechanisms underlying GI motility disorders will enable the development of better diagnostic and therapeutic tools and the advancement of this field.

The importance of interstitial cells of cajal in the gastrointestinal tract

Gastrointestinal (GI) motility function and its regulation is a complex process involving collaboration and communication of multiple cell types such as enteric neurons, interstitial cells of Cajal (ICC), and smooth muscle cells. Recent advances in GI research made a better understanding of ICC function and their role in the GI tract, and studies based on different types of techniques have shown that ICC, as an integral part of the GI neuromuscular apparatus, transduce inputs from enteric motor neurons, generate intrinsic electrical rhythmicity in phasic smooth muscles, and have a mechanical sensation ability. Absence or improper function of these cells has been linked to some GI tract disorders. This paper provides a general overview of ICC; their discovery, subtypes, function, locations in the GI tract, and some disorders associated with their loss or disease, and highlights some controversial issues with regard to the importance of ICC in the GI tract.

Abnormal development of intrinsic innervation in murine embryos with anorectal malformations

INTRODUCTION

Constipation, soiling, and incontinence are common problems after definitive repair of anorectal malformations (ARMs) in children. We studied the expression of substance P (SP), vasoactive intestinal peptide (VIP), and c-kit in the rectum of murine embryos with or without ARMs at later developmental stages.

METHODS

On the 9th embryonic day (E9), pregnant Institute of Cancer Research mice were fed etretinate, a synthetic vitamin A analogue (60 mg/kg), whereas controls were fed only with sesame oil. Embryos were excised between E14 and E18, and prepared for histological examination. The SP, VIP, and c-kit expressions were examined by immunohistochemical staining for the SP, VIP, and c-kit antigens, respectively.

RESULTS

On E14 and E15, the expression levels of the anti-SP and anti-VIP antibodies in the rectum did not differ between the control and etretinate-treated group. However, as compared to the controls, a decreased SP and VIP immunoreactivity was observed in the circular muscle layer of the rectum between E16 and E18. On the other hand, on E14 and E15, the expression of anti-c-kit antibody in the rectum did not differ between the etretinate-treated and control group. However, c-kit immunoreactivity was slightly higher in the circular muscle layer of the rectum in the controls on E16 and E17, and considerably higher on E18 than that of the muscle layer in the etretinate-treated group.

CONCLUSION

At later developmental stages, the expression levels of SP, VIP, and c-kit reduced in the circular muscle layer of the rectum in mice with etretinate-induced ARMs. This result indicates that reduced SP, VIP, and c-kit expression levels in the circular muscle layer may cause severe constipation in children who develop severe ARMs after definitive surgery.

Constipation in childhood

Constipation in children is an often long-lasting pediatric functional gastrointestinal disorder with a worldwide prevalence varying between 0.7% and 29.6%, and estimated health-care costs of US$3.9 billion per year in the USA alone. The pathophysiology of childhood constipation is multifactorial and remains incompletely understood; however, withholding of stools, starting after an experience of a hard, painful, or frightening bowel movement is the most common cause found in children. A thorough medical history and physical examination, including a rectal examination in combination with a bowel diary, is sufficient in the majority of cases to diagnose constipation. The current standard treatment consists of education, toilet training, disimpaction, maintenance therapy and long-term follow-up. In the past decade, well-designed treatment trials in the pediatric population have emerged and long-term outcome studies have been completed. This Review summarizes the current knowledge of the clinical aspects of childhood constipation, including pathogenesis, diagnosis and treatment, with particular emphasis on the latest available data.

The interstitial cells of Cajal of the equine gastrointestinal tract: what we know so far

Gastrointestinal motility disorders are a serious problem in both veterinary and human medicine and may represent a dysfunction of the neural, muscular or pacemaker components (interstitial cells of Cajal) of bowel control. The interstitial cells of Cajal are considered to be the pacemakers and mediators of certain forms of neurotransmission in the gastrointestinal tract. These cells have been implicated, either primarily or secondarily, in the pathogenesis of gastrointestinal disease processes in which there is a prominent element of disturbance to intestinal motility. In the horse, their involvement has been implicated in large intestinal obstructive colic and grass sickness (equine dysautonomia). This review highlights the properties of the interstitial cells of Cajal and the role these cells play in orchestrating gastrointestinal motility patterns. In addition, it examines their role in intestinal motility disorders and summarises our current understanding of their importance in the equine gastrointestinal tract.

Ultrastructural changes in interstitial cells of Cajal in the gastric antrum of rats undergoing water immersion-restraint stress

AIM: To investigate the impact of chronic water immersion-restraint stress on the ultrastructure of interstitial cells of Cajal (ICC) in the gastric antrum of rats.

METHODS: Forty-eight male Sprague-Dawley rats were randomly and equally divided into six groups: three experimental groups and three matched control groups. The three experimental groups underwent water immersion-restraint stress for one hour daily for 3, 7 and 14 days, respectively, while the three control groups were allowed free access to food and water. On days 4, 15 and 28, the rats in both the experimental and control groups were sacrificed. Two pieces of antrum tissues were taken from each rat and fixed in 3% glutaraldehyde for electron microscopic examination.

RESULTS: ICC were normal in all the control groups but showed visible injuries in the three experimental groups. With the prolongation of the stress, the morphological damage became more evident in ICC, especially in inter-muscular ICC (ICC-MY) and intramuscular ICC (ICC-IM). Major ultrastructural changes in ICC included reduced number of gap junctions and organelles.

CONCLUSION: Chronic water immersion-restraint stress can lead to ultrastructural damage in ICC in the gastric antrum of rats.

Constipation in 44 patients implanted with an artificial bowel sphincter

PURPOSE

Constipation with or without obstructed defecation (OD) is frequent in patients with artificial bowel sphincter (ABS). The aims of this study were (1) to evaluate the functional outcome of ABS based on postoperative constipation and (2) to assess pre-implantation data to predict post-implantation constipation.

MATERIALS AND METHODS

Thirteen men and 31 women were followed up. Both fecal incontinence and constipation with and without OD were assessed after implantation. Pre-implantation characteristics were compared in patients with and without postoperative constipation.

RESULTS

After implantation, nine patients (20.4%) had constipation without OD, 16 patients (36.4%) had OD, and 19 patients (43.2%) had neither of these. Incontinence was significantly more frequent in patients with postoperative constipation with or without OD. In these patients, an increase in preoperative constipation, anismus, and ultraslow waves was noted.

CONCLUSION

Constipation with and without OD is frequent after implantation and interfere with the functional outcome of ABS.

Interstitial cells of Cajal reduce in number in recto-sigmoid Hirschsprung's disease and total colonic aganglionosis

Interstitial cells of Cajal (ICCs) play a key role in regulating gastrointestinal tract motility. The pathophysiological basis of colonic aperistalsis in Hirschsprung's disease (HD) is still not fully understood. Many studies reported that decreased numbers or disrupted networks of ICCs were associated with HD. Little information is available on the distribution of different subtypes of ICCs in HD. The aim of this study was to determine the alterations in density of different subtypes of ICC in colonic specimens of patients with total colonic and recto-sigmoid HD. Full thickness colonic specimens were obtained from five children with total colonic aganglionosis (TCA), sixteen with recto-sigmoid HD and seven controls. ICCs were visualized in frozen sections by c-Kit (CD117) fluorescent staining. In the control colon, c-Kit positive ICCs formed a dense network surrounding the myenteric plexus (IC-MY), along the submucosal surface of the circular muscle layer (IC-SM) and in the circular and longitudinal muscle layer (IC-IM). In the aganglionic region of the colon of the patients affected by HD, the number of ICCs (especially IC-IM and IC-SM) was markedly reduced and IC-MY networks were disrupted. Nearly total lack of three subtypes of ICCs was observed in the TCA specimens. This study demonstrated the altered distribution of different subtypes of ICCs in the resected colon of patients with recto-sigmoid HD and TCA. These findings suggest that the reduction of each subtype of ICCs may play an important role in the etiology of HD.

Apoptotic cell death of human interstitial cells of Cajal

Interstitial cells of Cajal (ICC) are specialized mesenchyme-derived cells that regulate contractility and excitability of many smooth muscles with loss of ICC seen in a variety of gut motility disorders. Maintenance of ICC numbers is tightly regulated, with several factors known to regulate proliferation. In contrast, the fate of ICC is not established. The aim of this study was to investigate whether apoptosis plays a role in the regulation of ICC numbers in the normal colon. ICC were identified by immunolabelling for the c-Kit receptor tyrosine kinase and by electron microscopy. Apoptosis was detected in colon tissue by immunolabelling for activated caspase-3, terminal dUTP nucleotide end labelling and by ultrastructural changes in the cells. Apoptotic ICC were identified and counted in double-labelled tissue sections. They were identified in all layers of the colonic muscle. In the muscularis propria 1.5 +/- 0.2% of ICC were positive for activated caspase-3 and in the circular muscle layer 2.1 +/- 0.9% of ICC were positive for TUNEL. Apoptotic ICC were identified by electron microscopy. Apoptotic cell death is a continuing process in ICC. The level of apoptosis in ICC in healthy colon indicates that these cells must be continually regenerated to maintain intact networks.

C-kit receptor in the human vas deferens: distinction of mast cells, interstitial cells and interepithelial cells

The molecular mechanisms underlying the regulation of vas deferens (VD) motility and semen emission are still poorly understood. Interstitial cells of Cajal (ICC), which harbour the c-kit receptor (CD117), provide the basis of coordinated gut motility. We investigated whether c-kit receptor-positive cells also exist in the normal human VD. Enzyme and fluorescence immunohistochemical techniques were applied on serial sections of human proximal, middle, and distal VD segments (n=49) employing 13 different monoclonal and polyclonal antibodies recognizing the c-kit receptor. The c-kit receptor was detected in either round- or spindle-shaped cells. On account of their antigenic profile, the round- and oval-shaped c-kit receptor-positive cells were identified as mast cells (MC) occurring in all layers of the VD except the epithelium. In contrast, two distinct populations of exclusively c-kit receptor-positive spindle-shaped cells were found within the lamina propria and, rarely, in the inner and outer smooth muscle layers, as well as within the epithelium. Different shaped c-kit receptor-positive MC and IC were present in all layers of the human VD. Our findings demonstrate the presence of different c-kit receptor-positive cells also in the human VD. Their rather ubiquitous distribution within the lamina propria and muscle layers suggests that IC and MC may modulate the neuromuscular transmission and the propagation of electrical signals in multiple systems involved in the draining of fluids. The importance of the c-kit receptor-positive interepithelial cells remains unclear.

C-Kit receptor (CD117) in the porcine urinary tract

C-Kit positive interstitial cells of Cajal (ICC) play an important role in the regulation of the smooth muscle motility, acting as internal pacemakers to provide the slow wave activity within various luminal organs. Recently c-Kit-(CD117)-positive interstitial cells (IC) have been shown in the genitourinary tract, but systematic studies on the distribution and density of IC within the urinary tract are still lacking. Therefore the aim of the present study was to analyze systematically the localization and distribution of the c-Kit receptor in the urinary tract of the pig using immunohistochemical and molecular methods. Tissue samples were harvested from the porcine urinary tract including renal calices and pelvis, ureteropelvic junction, proximal, middle and distal ureter, ureteral orifice, fundus, and corpus of the bladder and the internal urethral orifice. Small and large intestine specimen served as controls. Immunohistochemistry (APAAP, IF) was applied on serial frozen sections using four monoclonal and polyclonal antibodies recognizing CD117. Whole mounts of the porcine upper urinary tract were prepared and investigated using conventional and confocal fluorescence microscopy followed by three-dimensional reconstruction. UV-laser microdissection and RT-PCR were applied to confirm the immunohistochemical results. CD117-immunoreactivity labeled bipolar IC and round-shaped mast cells (MC) throughout the adventitia, tunica muscularis and submucosa within the whole porcine urinary tract. While MC were found continuously in all investigated segments, a gradient of bipolar IC was evident. The whole mount preparations gave a detailed cytomorphology of IC within the various layers of the porcine urinary tract. Whole mount preparations revealed closed apposition of bi- and tripolar c-Kit positive IC parallel to the smooth muscle bundles and to veins of the tunica muscularis and adventitia. In the urothelium single CD117-positive interepithelial cells were found. The highest density of CD117-positive cells was found at the ureteropelvic junction, however the differences in between the segments were minimal. Microdissection and RT-PCR confirmed the results uncovered by immunohistochemistry. The ubiquitous distribution of IC and their close relationship to smooth muscle provides strong evidence that IC could contribute to the intrinsic pacemaker activity within the porcine (upper and lower) urinary tract. The role of the interepithelial CD117-positive cells as mechanosensors or as a precursor cell in the regeneration of the urothelium, is conceivable.

Morphology of the interstitial cells of Cajal of the human ileum from foetal to neonatal life

The so-called interstitial cells of Cajal myenteric plexus (ICC-MP), interstitial cells of Cajal intramuscular (ICC-IM) and interstitial cells of Cajal deep muscular plexus (ICC-DMP) are the three types of ICC endowed within the intestinal muscle coat where they play different roles in gut motility. Studies on ICC ontogenesis showed ICC-MP in the human ileum by 7-9 weeks while information on ICC-IM and ICC-DMP in foetuses and newborns are not exhaustive. Functional recordings in the fasting state of prematurely born babies aged 28-37 weeks showed immature ileal motility. To gain more information on the time of appearance of the three ICC types in the human ileum and on the steps of the acquisition of mature features, we studied by c-kit immuno-histochemistry foetuses aged 17-27 weeks and newborns aged 36-41 weeks. In parallel, the maturative steps of enteric plexuses and muscle layers were immunohistochemically examined by using anti-neuron specific enolase (NSE), anti-S-100 and anti-alpha smooth muscle actin (alphaSMA) antibodies. The appearance and differentiation of all the ICC types were seen to occur in concomitance with those of the related nerve plexuses and muscle layers. ICC-MP appeared first, ICC-IM and ICC-DMP later and their differentiation was incomplete at birth. In conclusion, the ICC-MP, the intestinal pacemaker cells, in spite of absence of food intake, are already present during the foetal life and the ICC-IM appear by pre-term life, thus ensuring neurotransmission. The ICC-DMP and their related nerve plexus and smooth muscle cells, i.e. the intestinal stretch receptor, begin to differentiate at birth. These findings might help in predicting neonatal ileal motor behaviour and in interpreting the role of ICC abnormalities in the pathophysiology of intestinal motile disorders of neonates and young children.

Morphological and physiological changes of interstitial cells of Cajal after small bowel transplantation in rats

Intestinal dysmotility has been reported to be associated with a decreased number of interstitial cells of Cajal (ICCs). However, the chronological changes in ICCs after small bowel transplantation (SBT) have not yet been elucidated. In this study, we aimed to evaluate the chronological change of ICCs after SBT. Orthotopic syngeneic SBT was performed in rats. Graft specimens were obtained at postreperfusion, and on 1, 3, 7, 14, and 30 postoperative day (POD). Thereafter, immunohistochemical staining was performed and the spontaneous contractions measured. During the initial period after SBT, the temporal impairment of ICCs was found. In an immunohistochemical study, c-Kit-positive cells appeared to decrease on POD 0, 1, and 3. Thereafter, the number of cells increased gradually up to POD 7. In contrast, the recovery of the spontaneous contractile amplitude took more time. The frequency of the electrical signal was preserved at almost exactly the same levels throughout this experimental period. Although the network of ICCs was found to be temporarily impaired after SBT in an immunohistochemical examination, this change was reversible. Moreover, the recovery of the function of the intestinal motility associated with ICCs was delayed after the early postoperative period.

Enteric nervous system and developmental abnormalities in childhood

ENS consists of a complex network of neurons, organised in several plexuses, which interact by means of numerous neurotransmitters. It is capable of modulating the intestinal motility, exocrine and endocrine secretions, microcirculation and immune and inflammatory responses within the gastrointestinal tract, independent of the central nervous system. Though the embryological development of various plexuses are completed by mid-way of gestation, the maturation of neurons and nerve plexuses appear to continue well after birth. Therefore, any histological or functional abnormalities related to the gastrointestinal function must be investigated with the ongoing maturational processes in mind.

Scintigraphic evaluation of colonic motility in patients with anorectal malformations and constipation

BACKGROUND AND PURPOSE

Constipation is one of the major sequelae in patients after correction of anorectal anomalies (ARAs). The aim of the present work has been to assess the colonic transit time, using radioisotope scintigraphy, in patients operated for ARA and experiencing constipation in the follow-up. The results were compared with transit time from children with true functional constipation.

METHODS

Twelve or 32 patients operated for ARA during the period 1994-2003 experienced mild or severe constipation (6 with high or intermediate form of ARA and 6 with low type) at follow-up. The mean age of this group was 5.8 years. Eighteen patients, mean age 6.7 years, with true functional constipation were studied as well. Colonic transit times were investigated using radioisotope scintigraphy. Normal values for colonic transit time were derived from historical controls. Radioisotope diethylenetriamine pentaacetic acid labelled with indium 111 was administered orally to determine a segmental colonic transit. Images of the abdomen have been taken at 6, 24, 48, and again at 72 hours, if radioactivity was not cleared from the colon. To quantify colonic transit, we calculated the geometric centre (GC) dividing the colon into anatomic regions.

RESULTS

According to normal controls, 2 different type of delayed transit can be observed: (a) slow-transit constipation if GC at 48 hours is less than 4.1; (b) functional rectosigmoid obstruction (FRSO) if GC at 48 hours is 4.1 or more but less than 6.1 at 72 hours. Patients with functional constipation were divided into 2 groups: (a) slow-transit constipation in 12 patients with a GC at 48 hours of 3.7 +/- 0.5; (b) FRSO in 6 patients with a GC of 4.7 +/- 0.04 and 5.02 at 48 and 72 hours, respectively. Patients operated for high ARA had values characteristic of FRSO with GC at 48 hours of 5.1 +/- 0.8 and 4.75 +/- 0.5 at 72 hours. In low ARA, the transit times were similar to the ones observed in patients with high ARA at 48 hours with a GC of 4.9 +/- 0.5.

CONCLUSIONS

Patients with ARA frequently have functional sequelae in the postoperative period such as constipation. According to our results, constipation seems to be secondary to segmental motility disorders limited to the rectosigmoid area, similar to constipated children with FRSO. No evidence of more generalised motility disturbance, as previously postulated, could be recorded.

Cajal-like cells in the upper urinary tract: comparative study in various species

The interstitial cells of Cajal (ICC) play an important role in the control of gut motility. The recognition that the ICC cell membrane harbors the c-kit receptor (CD117) sparked rapid advancement in ICC research on the gut and certain pathologies using immunochemical and molecular methods. The question arises whether ICC exist in the upper urinary tract (UUT) and trigger motility. The present study analyzed the distribution of the c-kit receptor in the normal human UUT compared with various species. Immunohistochemistry (alkaline-phosphatase-anti-alkaline-phosphatase technique, immunofluorescence) was applied on serial sections using monoclonal and polyclonal antibodies recognizing the c-kit receptor. C-kit staining was compared with standard endothelial, epithelial, neurogenic, histiocytic, mast cell, and smooth muscle markers, as well as a negative control. Normal proximal, middle, and distal ureter segments were analyzed in rodents, carnivores, porcines, cow, and humans. In all species the c-kit receptor was detected in either round or spindle-shaped cells. Because of their antigenic profile, the round cells were identified as mast cells occurring in all layers of the ureteral wall except the urothelium and were more frequent in humans. In contrast, the population of spindle-shaped cells was marked only by anti-c-kit receptor antibodies, thus resembling ICC. These ICC-like cells were found among the inner and outer smooth muscle layers and in the lamina propria of all species. In humans, spindle-shaped cells were also found vertically oriented within the urothelium. Our morphological data present for the first time the distribution of ICC in the UUT of various species. The ubiquitous distribution in the entire pyeloureteral complex provides strong evidence that ICC generate electrical pacemaker activity within the UUT as an intrinsic system. Animal studies may help to understand the physiological importance of these ICC-like cells. The significance of these findings needs to be evaluated by functional studies and investigations of certain congenital pathologies with disturbance of the urinary outflow.

Paediatric constipation for adult surgeons - article 2: new microscopic abnormalities and therapies

Chronic constipation is a common condition in both adults and children. Children with chronic constipation frequently have symptoms that continue into adulthood. In the second part of the review we describe advances in the identification of abnormalities in the control of motility. The role of neurotransmitters in both paediatric and adult constipation is examined and the radical rethink of colonic dysmotility caused by the re-emergence of interstitial cells of Cajal is discussed. The recognition of chronic constipation as an heterogenous condition has led to the introduction of new therapies. Antegrade washouts through appendix stomas and an exciting new treatment with electrical interferential therapy may, in the future, result in a less invasive approach to the management of chronic constipation. An improved understanding of the assessment and management of chronic constipation in childhood is also likely to reduce the frequency and morbidity of chronic constipation in adults.

Aberrations of the intrinsic innervation of the anorectum in fetal rats with anorectal malformations

BACKGROUND

Fecal accumulation, constipation, soiling, and incontinence are common sequelae after repair of anorectal malformations (ARMs) in children. It is believed that besides the abnormalities of sacral roots, certain inherent abnormalities of the myenteric plexuses may play an important role in the final outcome after definitive repair.

METHODS

This study was conducted to investigate the distribution of neuron-specific enolase (NSE), vasoactive intestinal peptide (VIP), and substance P (SP)-100 neurotransmitters in the rectosigmoid and fistulous tract of the ethylenethiourea-treated rat with ARMs.

RESULTS

ARMs were induced by administering 1% ethylenethiourea (125 mg/kg) on gestational day 10, and the litter was harvested on gestational day 21 by cesarean section. Forty-eight controls and 63 with ARMs (46 high-type and 17 low-type) were recovered. Whole-mount preparations of each rectosigmoid and fistulous communication between the rectum and genitourinary tract were stained with fluorescent antibodies against NSE, VIP, and SP-100. The tissues were counterstained with Eriochrome black-T and methyl green dyes to improve the visualization of the myenteric plexuses.

CONCLUSIONS

The immunoreactivity of NSE, VIP, and SP-100 was markedly reduced in the rectum and fistulous tract of high-type ARMs and slightly reduced in low-type ARMs compared with controls. Intramural nerves stained by VIP and SP-100 antisera were decreased in both types of ARM, indicating that both inhibitory and excitatory motor neural elements were affected, and this may explain the distal colonic dysmotility seen postoperatively in both high and low ARMs.

Development of the enteric nervous system, smooth muscle and interstitial cells of Cajal in the human gastrointestinal tract

The generation of functional neuromuscular activity within the pre-natal gastrointestinal tract requires the coordinated development of enteric neurons and glial cells, concentric layers of smooth muscle and interstitial cells of Cajal (ICC). We investigated the genesis of these different cell types in human embryonic and fetal gut material ranging from weeks 4-14. Neural crest cells (NCC), labelled with antibodies against the neurotrophin receptor p75NTR, entered the foregut at week 4, and migrated rostrocaudally to reach the terminal hindgut by week 7. Initially, these cells were loosely distributed throughout the gut mesenchyme but later coalesced to form ganglia along a rostrocaudal gradient of maturation; the myenteric plexus developed primarily in the foregut, then in the midgut, and finally in the hindgut. The submucosal plexus formed approximately 2-3 weeks after the myenteric plexus, arising from cells that migrated centripetally through the circular muscle layer from the myenteric region. Smooth muscle differentiation, as evidenced by the expression of alpha-smooth muscle actin, followed NCC colonization of the gut within a few weeks. Gut smooth muscle also matured in a rostrocaudal direction, with a large band of alpha-smooth muscle actin being present in the oesophagus at week 8 and in the hindgut by week 11. Circular muscle developed prior to longitudinal muscle in the intestine and colon. ICC emerged from the developing gut mesenchyme at week 9 to surround and closely appose the myenteric ganglia by week 11. By week 14, the intestine was invested with neural cells, longitudinal, circular and muscularis mucosae muscle layers, and an ICC network, giving the fetal gut a mature appearance.

Chronic constipation in children: organic disorders are a major cause

Diagnostic tools for paediatric chronic constipation have been limited, leading to over 90% of patients with treatment-resistant constipation being diagnosed with chronic idiopathic constipation, with no discernible organic cause. Work in our institution suggests that a number of children with intractable symptoms actually have slow colonic transit leading to slow transit constipation. This paper reviews recent data suggesting that a significant number of the children with chronic treatment-resistant constipation may have organic causes (slow colonic transit and outlet obstruction) and suggests new approaches to the management of children with chronic treatment-resistant constipation.

Gastroschisis in the rat model is associated with a delayed maturation of intestinal pacemaker cells and smooth muscle cells

BACKGROUND

A pacemaker system is required for peristalsis generation. The interstitial cells of Cajal (ICC) are considered the intestinal pacemaker, and are identified by expression of the c-kit gene--encoded protein. Gastroschisis is characterized by a severe gastrointestinal dysmotility in newborns. In spite of this clinical picture, few studies have focused on smooth muscle cells (SMC) morphology and none on ICC. Therefore, their morphology has been studied in fetuses at term in the rat model of gastroschisis.

METHODS

At 18.5 day's gestation (E18.5), 10 rat fetuses were killed, 10 underwent surgical creation of gastroschisis, and 10 underwent manipulation only. The small intestine of the latter 2 groups was harvested at E21.5. Specimens were processed for H&E, c-kit and actin (alpha smooth muscle antibody [alpha-SMA]) immunohistochemistry, and transmission electron microscopy (TEM).

RESULTS

In the controls, SMC were c-kit+ and alpha-SMA+, with labeling intensity increasing by age. At E21.5, some cells around the Auerbach's plexus were more intensely c-kit+, and differentiating ICC were seen under TEM at this level. Gastroschisis fetuses had no c-kit+ cells referable to ICC. In the more damaged loops, SMC were very faintly c-kit+ and alpha-SMA+. Under TEM, there were few differentiated SMC and no presumptive ICC. In the less-damaged loops, SMC were faintly c-kit+ and alpha-SMA+ and had ultrastructural features intermediate between those of E18.5 and E21.5 controls; ICC were very immature.

CONCLUSIONS

ICC and SMC differentiation is delayed in gastroschisis with the most damaged loops showing the most incomplete picture. These findings might help in understanding the delayed onset of peristalsis and the variable time-course of the recover seen in babies affected by gastroschisis.

The development and distribution of the interstitial cells of Cajal in the intestine of the equine fetus and neonate

This study set out to determine the pattern of development and distribution of the interstitial cells of Cajal (ICC) in the intestinal tract of the equine fetus and neonate. Intestinal tissue samples from 12 naturally aborted equine fetuses and three euthanized neonates were collected and fixed in formalin prior to applying standard immunohistochemical labelling techniques targeting the c-Kit protein of the ICC. At 6 months of gestation, a network of ICC was present in the myenteric plexus region of both the small and the large intestine. ICC were also present within the circular muscle layer. In the large intestine, a proximal to distal gradient of distribution was evident, with few ICC observed in the more distal parts of the large intestine in the younger fetuses compared with the near-term animals. A transmural gradient of distribution was also evident within the large intestine, with the most luminal part of the muscularis externa being the last area to be colonized by ICC. This region did not appear fully developed until the early neonatal period. An increased density of ICC was noted throughout the large intestine in the regions of the taenial bands in all animals. This study is the first to describe ICC development and distribution in the equine fetus and neonate.

Cajal-like cells in the human upper urinary tract

PURPOSE

Interstitial cells of Cajal (ICCs) have an important role in the regulation of gut motility as they are responsible for the slow wave activity of smooth muscle. It is still unknown if ICCs also occur in the human upper urinary tract. Since these cells express and are marked by the c-kit receptor CD117, we investigated its occurrence and distribution along the human upper urinary tract.

MATERIALS AND METHODS

Tissues from 56 human ureters, spanning proximal, middle and distal ureter segments, were analyzed by indirect immunohistochemistry using the alkaline phosphatase-anti-alkaline phosphatase method and double labeling immunofluorescence on consecutive tissue sections. Several monoclonal and polyclonal antibodies to c-kit receptor were used in combination with various cell markers for histiocytic, mast cell, endothelial, epithelial, neuronal, smooth muscle and stem cell differentiation.

RESULTS

The c-kit receptor was found in 3 cell types of the ureter and in round or spindle-shaped cells. Due to their antigenic profile the first one was revealed as mast cells occurring in all layers of the ureteral wall except the urothelium. In contrast, the population of spindle-shaped cells was only marked by c-kit receptor, thus, resembling ICCs. These ICC-like cells were found among the inner and outer smooth muscle layers, and in the lamina propria. They showed a slight decrease from proximal to distal ureteral segments. However, unlike intestinal ICCs their cytomorphology differed and some cells, representing the third group of c-kit receptor positive cells, were found within the urothelium.

CONCLUSIONS

Our data demonstrate the presence of ICC-like cells and their ubiquitous distribution in the human ureter. The physiological importance and pathological significance of these findings must be evaluated by functional studies and investigations of certain pathological with urinary outflow disturbance conditions.

Distribution of interstitial cells of Cajal in the internal anal sphincter of patients with internal anal sphincter achalasia and Hirschsprung disease

CONTEXT

Interstitial cells of Cajal (ICCs) are pacemaker cells in the smooth muscles of the gut. The internal anal sphincter (IAS) is the most caudal part of gastrointestinal tract. It has the important function of maintaining fecal continence. It has been proposed that ICCs in the IAS mediate the inhibitory innervation of the recto-anal reflexes.

OBJECTIVE

To investigate the distribution of ICCs in the normal IAS and in the IAS of children diagnosed with internal anal sphincter achalasia (IASA) and Hirschsprung disease (HD).

METHODS

At the time of IAS myectomy, specimens of the IAS were taken from 8 patients with IASA, 4 patients with HD, and 4 normal controls. All specimens were examined using anti-c-Kit and antiperipherin antibodies; immunolocalization was detected with light microscopy. Density of the ICCs was graded by computerized image analysis.

RESULTS

There was strong peripherin immunoreactivity in the ganglia cells and nerve fibers in the normal IAS. The number of peripherin-positive nerve fibers was markedly reduced in the IAS in patients with IASA. In HD patients, there was lack of peripherin immunoreactivity in the IAS, but hypertrophic nerve trunks stained strongly. Many c-Kit-positive ICCs were present among the muscle fibers and between the muscle bundles in the normal IAS. In HD and IASA patients, ICCs were absent or markedly reduced.

CONCLUSION

Altered distribution of ICCs in the internal sphincter in IASA and HD may contribute to motility dysfunction in these patients.

Delayed maturation of interstitial cells of Cajal in meconium obstruction

BACKGROUND/PURPOSE

The etiology of meconium obstruction without cystic fibrosis is unclear. Interstitial cells of Cajal (ICC) function as pacemakers in gut motility and may play a role in the pathophysiology of the disease.

METHODS

The ICC were examined by immunohistochemical staining with anti-c-kit antibody in the bowel walls of 6 neonates who had meconium obstruction without cystic fibrosis, and the results were compared with specimens from normal neonates (n = 2).

RESULTS

Six patients underwent ileostomy between 2 and 15 days after birth, and 5 of them presented with microcolon. Ganglion cells were present in the ileum and colon. Whereas ICC were evenly distributed in the control specimens, they were not seen at the time of ileostomy in the colons of 2 patients, and the other 4 showed scanty distribution in muscle layers. However, ileum showed normal distribution of ICC in all patients. The ileostomies were closed between 39 and 104 days of age, and the ICC distribution was changed to a normal pattern in the colons of all 6 patients. Their bowel movements were restored to normal after closure.

CONCLUSION

The findings of this study suggest that delayed maturity of ICC may be a cause of meconium obstruction without cystic fibrosis.

Understanding and controlling the enteric nervous system

The enteric nervous system or the 'Little Brain' of the gut controls gastrointestinal motility and secretion, and is involved in visceral sensation. In this chapter, new developments in understanding the function of the enteric nervous system are described. In particular, the interaction of this system with the interstitial cells of Cajal, the pacemaker cells of the gut, is highlighted. The importance of the interaction between the enteric nervous system and the immune system is discussed, especially in relation to functional bowel disorders and post-operative ileus. Evidence is also provided that neurones can change their function and phenotype, a phenomenon called neuronal plasticity, which contributes to the pathogenesis of visceral hypersensitivity. Finally, new developments in stem cell transplantation are described. All these new insights should lead to a better understanding of the enteric nervous system and hopefully to better ways of controlling it.

Presence of in vitro electrical activity in the ileum of horses with enteric nervous system pathology: equine dysautonomia (grass sickness)

Equine dysautonomia (grass sickness) is a frequently fatal disease of horses characterised by intestinal stasis. Interstitial cells of Cajal (ICC) are the pacemakers and mediators of neurotransmission in the gastrointestinal tract. Impaired ICC-mediated control of motility has been implicated in intestinal disorders in laboratory mammals, humans and in equine grass sickness. The aim of this study was to compare the in vitro electrical properties of ileum from grass sickness cases with horses free from gastrointestinal disease. Intracellular microelectrode recordings were made from smooth muscle cells in cross-sectional preparations of equine ileum, superfused in vitro. Samples were taken from six horses with grass sickness and from eight horses free from gastrointestinal disease, all euthanised on humane grounds. Ileal tissues were processed for haematoxylin and eosin histology, and c-Kit immunohistochemistry. Membrane potential oscillations were recorded in the ileal preparations from four of the six horses with grass sickness and from all of the normal horses. A waxing and waning pattern of the membrane potential oscillation activity was noted in some cells. In comparison to the normal horses, the membrane potential oscillations in grass sickness horses had a significantly reduced frequency (P = 0.0001) and increased duration (P = 0.0002). Immunohistochemistry revealed the presence but reduction of ICC in grass sickness. Histological assessment of the same tissues used for analysis of the ICC showed the depletion and pathology of the enteric neurons in grass sickness. Therefore, the majority of ileal preparations from grass sickness-affected horses exhibited prominent membrane potential oscillation activity suggesting that, although the neural elements are damaged severely, the ICC-mediated pacemaker function remains intact.

The interstitial cells of Cajal and a gastroenteric pacemaker system

In spite of a claim by Kobayashi (1990) that they do not correspond to the cells originally depicted by CAJAL, a particular category of fibroblast-like cells have been identified in the gut by electron microscopy (Faussone-Pellegrini, 1977; Thuneberg, 1980) and by immunohistochemistry for Kit protein (Maeda et al., 1992) under the term of the "interstitial cells of Cajal (ICC)". Generating electrical slow waves, the ICC are intercalated between the intramural neurons and the effector smooth muscular cells, to form a gastroenteric pacemaker system. ICC at the level of the myenteric plexus (IC-MY) are multipolar cells forming a reticular network. The network of IC-MY which is believed to be the origin of electrical slow waves is morphologically independent from but associated with the myenteric plexus. On the other hand, intramuscular ICC (IC-IM) usually have spindle-shaped contours arranged in parallel with the bulk smooth muscle cells. Associated with nerve bundles and blood vessels, the IC-IM possess receptors for neurotransmitters and such circulating hormones as cholecystokinin, suggesting their roles in neuromuscular and hormone-muscular transmissions. In addition, gap junctions connect the IC-MY and IC-IM, thereby realizing the electrically synchronized integrity of ICC as a pacemaker system in the gut. The smooth muscle cells are also coupled with ICC via gap junctions, and the functional unit thus formed enables rhythmically synchronized contractions and relaxations. It has recently been found that a lack of Kit-expressing cells may induce hyper-contractility of the tunica muscularis in vitro, whereas a decrease in Kit expression within the muscle wall causes dysmotility-like symptoms in vivo. The pacemaker system in the gut thus seems to play a critical role in the maintenance of both moderate and normal motility of the digestive tract. A loss of Kit positive cells has been detected in several diseases with an impaired motor activity, including diabetic gastroenteropathy. Pathogenesis of these diseases is thought to be accounted for by impaired slow waves and neuromuscular transmissions; a pacemaker disorder may possibly induce a dysmotility-like symptom called 'gastroenteric arrhythmia'. A knowledge of the structure and function of the ICC and the pacemaker system provides a basis for clarifying the normal mechanism and the pathophysiology of motility in the digestive tract.

Loss of interstitial cells of Cajal and development of electrical dysfunction in murine small bowel obstruction

1. Partial obstruction of the murine ileum led to changes in the gross morphology and ultrastructure of the tunica muscularis. Populations of interstitial cells of Cajal (ICC) decreased oral, but not aboral, to the site of obstruction. Since ICC generate and propagate electrical slow waves in gastrointestinal muscles, we investigated whether the loss of ICC leads to loss of function in partial bowel obstruction. 2. Changes in ICC networks and electrical activity were monitored in the obstructed murine intestine using immunohistochemistry, electron microscopy and intracellular electrophysiological techniques. 3. Two weeks following the onset of a partial obstruction, the bowel increased in diameter and hypertrophy of the tunica muscularis was observed oral to the obstruction site. ICC networks were disrupted oral to the obstruction, and this disruption was accompanied by the loss of electrical slow waves and responses to enteric nerve stimulation. These defects were not observed aboral to the obstruction. 4. Ultrastructural analysis revealed no evidence of cell death in regions where the lesion in ICC networks was developing. Cells with a morphology intermediate between smooth muscle cells and fibroblasts were found in locations that are typically populated by ICC. These cells may have been the redifferentiated remnants of ICC networks. 5. Removal of the obstruction led to the redevelopment of ICC networks and recovery of slow wave activity within 30 days. Neural responses were partially restored in 30 days. 6. These data describe the plasticity of ICC networks in response to partial obstruction. After obstruction the ICC phenotype was lost, but these cells regenerated when the obstruction was removed. This model may be an important tool for evaluating the cellular/molecular factors responsible for the regulation and maintenance of the ICC phenotype.

Loss of interstitial cells of Cajal and development of electrical dysfunction in murine small bowel obstruction

1. Partial obstruction of the murine ileum led to changes in the gross morphology and ultrastructure of the tunica muscularis. Populations of interstitial cells of Cajal (ICC) decreased oral, but not aboral, to the site of obstruction. Since ICC generate and propagate electrical slow waves in gastrointestinal muscles, we investigated whether the loss of ICC leads to loss of function in partial bowel obstruction. 2. Changes in ICC networks and electrical activity were monitored in the obstructed murine intestine using immunohistochemistry, electron microscopy and intracellular electrophysiological techniques. 3. Two weeks following the onset of a partial obstruction, the bowel increased in diameter and hypertrophy of the tunica muscularis was observed oral to the obstruction site. ICC networks were disrupted oral to the obstruction, and this disruption was accompanied by the loss of electrical slow waves and responses to enteric nerve stimulation. These defects were not observed aboral to the obstruction. 4. Ultrastructural analysis revealed no evidence of cell death in regions where the lesion in ICC networks was developing. Cells with a morphology intermediate between smooth muscle cells and fibroblasts were found in locations that are typically populated by ICC. These cells may have been the redifferentiated remnants of ICC networks. 5. Removal of the obstruction led to the redevelopment of ICC networks and recovery of slow wave activity within 30 days. Neural responses were partially restored in 30 days. 6. These data describe the plasticity of ICC networks in response to partial obstruction. After obstruction the ICC phenotype was lost, but these cells regenerated when the obstruction was removed. This model may be an important tool for evaluating the cellular/molecular factors responsible for the regulation and maintenance of the ICC phenotype.

A reduction in interstitial cells of Cajal in horses with equine dysautonomia (grass sickness)

Equine dysautonomia (grass sickness) is a common, frequently fatal disease of horses characterised by dysfunction of the gastrointestinal tract. Interstitial cells of Cajal are the c-Kit-immunoreactive cells responsible for the generation of pacemaker activity in gastrointestinal smooth muscle. Impairment of this pacemaker action has been implicated in several motility disorders in humans and laboratory mammals. The aim of this study was to test the hypothesis that changes in interstitial cells of Cajal may be involved in the pathophysiology of the intestinal dysfunction observed in equine grass sickness. Interstitial cells of Cajal were identified using immunohistochemical labelling with an anti-c-Kit antibody and their density was assessed using a semi-quantitative grading system. Segments of ileum were examined from 24 horses free from gastrointestinal disease and compared to tissues from 28 horses with grass sickness. Segments of the pelvic flexure region of the large colon were examined from 13 horses free from gastrointestinal disease and compared to tissues from 10 horses with grass sickness. In horses with grass sickness, interstitial cells of Cajal were significantly decreased in both the myenteric plexus and circular muscle regions of both ileum and pelvic flexure compared to normal animals. Therefore, it is possible that the decline in interstitial cells of Cajal may be an important factor in the development of intestinal dysmotility observed in grass sickness.

Posterior sagittal approach: megasigmoid resection and anal reconstruction for severe constipation and fecal incontinence after anoplasty

PURPOSE

The aim of this study was to present the technique of megasigmoid resection and anal reconstruction by complete posterior sagittal approach for the children with severe constipation and fecal incontinence after anoplasty.

METHODS

Six patients (age, 2 to 18 years) born with imperforate anus and originally treated with perineal anoplasty suffered from intractable constipation and fecal incontinence. Contrast enema showed massive dilated and aperistaltic rectosigmoid colon with fecal impaction. Resection of the dilated bowel and anal reconstruction were completely performed by posterior sagittal approach.

RESULTS

The mean operating time was 205 minutes (range, 125 to 265 minutes) and the average length of resected colon was 23.3 cm (range, 10 to 40 cm). There were no intraoperative or postoperative complications. By 2 to 4 months after the operation, all patients obtained voluntary bowel movement. On follow-up at 6 to 24 months postoperative, no patient had constipation or required use of the laxatives again. Four of 6 patients suffered from grade 1 soiling, and the other 2 had grade greater than 1 soiling. None had urinary retention or incontinence after the procedure.

CONCLUSION

Resection of dilated rectosigmoid colon and anal reconstruction for the patients with severe constipation and fecal incontinence after anoplasty can be performed successfully using a posterior sagittal approach.

Idiopathic gastric perforation in neonates and abnormal distribution of intestinal pacemaker cells

BACKGROUND/PURPOSE

The etiology of idiopathic gastric perforation (IGP) in neonates is unclear. Interstitial cells of Cajal (ICC) express tyrosine kinase receptor C-kit, and act as gastrointestinal pacemaker cells. Stem cell factor (SCF) is a C-kit ligand and plays an important role in immune system homeostasis in the gastrointestinal tract. The authors hypothesized that abnormal distribution of ICC or SCF in the gastric wall (ie, abnormal motility or impaired immunity) could predispose the stomach to IGP.

METHODS

Stomachs obtained at postmortem from neonates who died of IGP (n = 7) and other causes (control group; n = 10) were used. Biopsy sections were taken at random from various sites in the stomach, including macroscopically intact areas, and labeled immunohistochemically using antibodies to C-kit(a marker for ICC) and SCF.

RESULTS

In all control specimens, ICC were present between the muscle layers and around the myenteric plexuses of the stomach wall. In contrast, ICC were absent in all biopsy sections from 3 of the 7 IGP stomachs. In the remaining 4 IGP stomachs, there were fewer ICC in the muscle layers compared with controls, and ICC were absent around the myenteric plexuses. The distribution of SCF immunoreactivity in IGP and control specimens was similar.

CONCLUSION

The findings suggest that a lack of ICC (ie, gastric hypomotility) may be implicated in the etiology of IGP in neonates.

Slow transit constipation: a model of human gut dysmotility. Review of possible aetiologies

Slow transit constipation is a severe condition of gut dysmotility that predominantly affects young women and may result in surgical intervention. Current medical treatments for STC are often ineffective, and the outcome of surgery is unpredictable. STC was first described almost a century ago. Since this time, progress in improving therapy for this condition has been complicated by a lack of understanding of the aetiology, and great variation in the methods and criteria used for the study of patients with this debilitating disorder. It is difficult to find unequivocal data, and harder still to give a definitive picture of the cause or causes of STC. Here we consider the evidence for various aetiologies of STC, in the light of the physiological and pathological findings.

Comparative morphology of interstitial cells of Cajal: ultrastructural characterization

The shape, distribution, and ultrastructural features of interstitial cells of Cajal (ICC) of different tissue layers and organs of the rat and guinea-pig digestive tract were described and compared with the corresponding cells in other species including mice, dogs, and humans, as reported in the literature. By light microscopy, the best marker for ICC appeared to be immunoreactivity for c-Kit. Ultrastructurally, ICC were characterized by the presence of many mitochondria, bundles of intermediate filaments, and gap junctions, which linked ICC with each other. However, ICC were morphologically heterogeneous and had particular features, depending on their tissue and organ location and species. ICC in the deep muscular plexus of the small intestine and in the submuscular plexus of the colon were the most like smooth muscle cells, and had a distinct basal lamina and numerous caveolae. In contrast, ICC of Auerbach's plexus at all levels of the gastrointestinal tract were the least like smooth muscle cells. They most closely resembled unremarkable fibroblasts. ICC within the circular muscle layer were intermediate in form. In addition to the tissue specificity, some organ and species specificity could be distinguished. The structural differences between ICC may be determined by their microenvironment, including the effects of mechanical force, type of nerve supply, and spacial relationship with smooth muscle cells.

Interstitial cells of Cajal in human gut and gastrointestinal disease

This paper reviews the distribution of interstitial cells of Cajal (ICC) in the human gastrointestinal (GI) tract, based on ultrastructural and immunohistochemical evidence. The distribution and morphology of ICC at each level of the normal GI tracts is addressed from the perspective of their functional significance. Alterations of ICC reported in achalasia of cardia, infantile hypertrophic pyloric stenosis, chronic intestinal pseudoobstruction, Hirschsprung's disease, inflammatory bowel diseases, slow transit constipation, and some other disorders of GI motility as well as in gastrointestinal stromal tumors are reviewed, with emphasis on the place of ICC in the pathophysiology of disease.

Heme oxygenase-2 distribution in anorectum: colocalization with neuronal nitric oxide synthase

Recent investigations have suggested carbon monoxide (CO) as a putative messenger molecule. Although several studies have implicated the heme oxygenase (HO) pathway, responsible for the endogenous production of CO, in the neuromodulatory control of the internal anal sphincter (IAS), its exact role is not known. Nitric oxide, produced by neuronal nitric oxide synthase (nNOS) of myenteric neurons, is an important inhibitory neural messenger molecule mediating nonadrenergic noncholinergic (NANC) relaxation of the IAS. The present studies were undertaken to investigate in detail the presence and coexistence of heme oxygenase-2 (HO-2) with nNOS in the opossum anorectum. In perfusion-fixed, frozen-sectioned tissue, HO-2 immunoreactive (IR) and nNOS IR nerves were identified using immunocytochemistry. Ganglia containing HO-2 IR neuronal cell bodies were present in the myenteric and submucosal plexuses throughout the entire anorectum. Colocalization of HO-2 IR and nNOS IR was nearly 100% in the IAS and decreased proximally from the anal verge. In the rectum, colocalization of HO-2 IR and nNOS IR was approximately 70%. Additional confocal microscopy studies using c-Kit staining demonstrated the localization of HO-2 IR and nNOS IR in interstitial cells of Cajal (ICC) of the anorectum. From the high rate of colocalization of HO-2 IR and nNOS IR in the IAS as well as the localization of HO-2 IR and nNOS IR in ICC in conjunction with earlier studies of the HO pathway, we speculate an interaction between HO and NOS pathways in the NANC inhibitory neurotransmission of the IAS and rectum.

New insights into neural injury, repair, and adaptation in visceral afferents and the enteric nervous system

In this brief review, we focus on some of the proposed mechanisms of injury in peripheral visceral afferents (sensory) pathways and the enteric nervous system, including the interstitial cells of Cajal. Injury involving afferent neurons is discussed because of the relevance of these neurons to the pathophysiology of pain syndromes. The effect of various noxious stimuli on sensory and enteric neural function is examined. Finally, we discuss recent data on the role of autoimmune antibodies in neuronal injury in systemic diseases, such as diabetes mellitus and the Lambert-Eaton myasthenic syndrome. Neither central nervous system manifestations of peripheral nerve injury nor functional bowel disorders are addressed in this review. An improved understanding of the pathophysiology of peripheral neuronal dysfunction will probably result in new treatment strategies for a broad range of gastrointestinal disorders, including constipation, pseudo-obstruction, ileus, and inflammatory bowel disorders.

Interstitial cells of Cajal in human gut and gastrointestinal disease

This paper reviews the distribution of interstitial cells of Cajal (ICC) in the human gastrointestinal (GI) tract, based on ultrastructural and immunohistochemical evidence. The distribution and morphology of ICC at each level of the normal GI tracts is addressed from the perspective of their functional significance. Alterations of ICC reported in achalasia of cardia, infantile hypertrophic pyloric stenosis, chronic intestinal pseudoobstruction, Hirschsprung's disease, inflammatory bowel diseases, slow transit constipation, and some other disorders of GI motility as well as in gastrointestinal stromal tumors are reviewed, with emphasis on the place of ICC in the pathophysiology of disease.

Guide to the identification of interstitial cells of Cajal

The interstitial cell of Cajal, abbreviated ICC, is a specific cell type with a characteristic distribution in the smooth muscle wall throughout the alimentary tract in humans and laboratory mammals. The number of publications relating to ICC is rapidly increasing and demonstrate a rich variation in the structure and organization of these cells. This variation is species-, region-, and location-dependent. We have chosen to define a "reference ICC," basically the ICC in the murine small intestine, as a platform for discussion of variability. The growing field of ICC markers for light and electron microscopy is reviewed. Although there is a rapidly increasing number of approaches applicable to bright field and fluorescence microscopy, the location of markers by electron microscopy still suffers from inadequate preservation of ultrastructural detail. Finally, we summarize evidence related to ICC ultrastructure under conditions differing from those of the normal, adult individual (during differentiation, in pathological conditions, transplants, mutants, and in cell culture).

Comparative morphology of interstitial cells of Cajal: ultrastructural characterization

The shape, distribution, and ultrastructural features of interstitial cells of Cajal (ICC) of different tissue layers and organs of the rat and guinea-pig digestive tract were described and compared with the corresponding cells in other species including mice, dogs, and humans, as reported in the literature. By light microscopy, the best marker for ICC appeared to be immunoreactivity for c-Kit. Ultrastructurally, ICC were characterized by the presence of many mitochondria, bundles of intermediate filaments, and gap junctions, which linked ICC with each other. However, ICC were morphologically heterogeneous and had particular features, depending on their tissue and organ location and species. ICC in the deep muscular plexus of the small intestine and in the submuscular plexus of the colon were the most like smooth muscle cells, and had a distinct basal lamina and numerous caveolae. In contrast, ICC of Auerbach's plexus at all levels of the gastrointestinal tract were the least like smooth muscle cells. They most closely resembled unremarkable fibroblasts. ICC within the circular muscle layer were intermediate in form. In addition to the tissue specificity, some organ and species specificity could be distinguished. The structural differences between ICC may be determined by their microenvironment, including the effects of mechanical force, type of nerve supply, and spacial relationship with smooth muscle cells.

Development and plasticity of interstitial cells of Cajal

Interstitial cells of Cajal (ICC) are the pacemakers in gastrointestinal (GI) muscles, and these cells also mediate or transduce inputs from the enteric nervous system. Different classes of ICC are involved in pacemaking and neurotransmission. ICC express specific ionic conductances that make them unique in their ability to generate and propagate slow waves in GI muscles or transduce neural inputs. Much of what we know about the function of ICC comes from developmental studies that were made possible by the discoveries that ICC express c-kit and proper development of ICC depends upon signalling via the Kit receptor pathway. Manipulating Kit signalling with reagents to block the receptor or downstream signalling pathways or by using mutant mice in which Kit or its ligand, stem cell factor, are defective has allowed novel studies into the specific functions of the different classes of ICC in several regions of the GI tract. Kit is also a surface antigen that can be used to conveniently label ICC in GI muscles. Immunohistochemical studies using Kit antibodies have expanded our knowledge about the ICC phenotype, the structure of ICC networks, the interactions of ICC with other cells in the gut wall, and the loss of ICC in some clinical disorders. Preparations made devoid of ICC have also allowed analysis of the consequences of losing specific classes of ICC on GI motility. This review describes recent advances in our knowledge about the development and plasticity of ICC and how developmental studies have contributed to our understanding of the functions of ICC. We have reviewed the clinical literature and discussed how loss or defects in ICC affect GI motor function.