Loss of CD117 (c-kit)- and CD34-positive ICC and associated CD34-positive fibroblasts defines a subpopulation of chronic intestinal pseudo-obstruction

Ca2+ dynamics in interstitial cells: foundational mechanisms for the motor patterns in the gastrointestinal tract

The gastrointestinal (GI) tract displays multiple motor patterns that move nutrients and wastes through the body. Smooth muscle cells (SMCs) provide the forces necessary for GI motility, but interstitial cells, electrically coupled to SMCs, tune SMC excitability, transduce inputs from enteric motor neurons, and generate pacemaker activity that underlies major motor patterns, such as peristalsis and segmentation. The interstitial cells regulating SMCs are interstitial cells of Cajal (ICC) and PDGF receptor (PDGFR)α+ cells. Together these cells form the SIP syncytium. ICC and PDGFRα+ cells express signature Ca2+-dependent conductances: ICC express Ca2+-activated Cl- channels, encoded by Ano1, that generate inward current, and PDGFRα+ cells express Ca2+-activated K+ channels, encoded by Kcnn3, that generate outward current. The open probabilities of interstitial cell conductances are controlled by Ca2+ release from the endoplasmic reticulum. The resulting Ca2+ transients occur spontaneously in a stochastic manner. Ca2+ transients in ICC induce spontaneous transient inward currents and spontaneous transient depolarizations (STDs). Neurotransmission increases or decreases Ca2+ transients, and the resulting depolarizing or hyperpolarizing responses conduct to other cells in the SIP syncytium. In pacemaker ICC, STDs activate voltage-dependent Ca2+ influx, which initiates a cluster of Ca2+ transients and sustains activation of ANO1 channels and depolarization during slow waves. Regulation of GI motility has traditionally been described as neurogenic and myogenic. Recent advances in understanding Ca2+ handling mechanisms in interstitial cells and how these mechanisms influence motor patterns of the GI tract suggest that the term "myogenic" should be replaced by the term "SIPgenic," as this review discusses.

Prokinetic effects of Citrus reticulata and Citrus aurantium extract with/without Bupleurum chinense using multistress-induced delayed gastric emptying models

CONTEXT

Citrus aurantium L (Rutaceae) (Au) and Citrus reticulata Blanco (Rutaceae) (Ci) are commonly used as couplet prokinetics and Bupleurum chinense DC. (Umbelliferae) (Bup) is an herbal antidepressant in traditional Chinese medicine.

OBJECTIVE

This study evaluates the synergistic prokinetic effects of Bup with Au and Ci in mice suffering from multistress-induced delayed gastric emptying (DGE).

MATERIALS AND METHODS

Kunming mice were divided into four groups: control, DGE, AuCi and AuCiBup. Mice were gavaged with AuCi (14.25 g/kg) or AuCiBup (22.13 g/kg) extract for 12 days. Gastric reminder rate, intestinal driving ratio, sucrose preference and open field test were examined, and serotonin (5-HT), motilin (MTL), substance P (SP), 5-HT₄R and c-kit were assayed. Intracellular Ca²⁺ levels in primary cultured gastric smooth muscle cells (GSMCs) were determined.

RESULTS

Both AuCi and AuCiBup treatment significantly reduced gastric residual rate (39.5% and 67.7%, p < 0.01). Higher serum levels of 5-HT, MTL and SP were observed in treatment groups (AuCi: 0.060 mg/L, AuCiBup: 0.089 mg/L, DGE: 0.025 mg/L, p < 0.01). The expression of 5-HT₄R and c-kit in the antrum and duodenum was upregulated after treatment (AuCi and AuCiBup, 4.3-times, 2.8-times to DGE, p < 0.01). Medicated serums of AuCi and AuCiBup effectively increased the influx of Ca²⁺ into GSMCs in vitro (1.8-times, p < 0.01). In terms of 5-HT₄R expression, circulatory contents of 5-HT and SP and Ca²⁺ influx, AuCiBup demonstrated better prokinetic effects than AuCi.

CONCLUSIONS

These findings indicate the potential for developing combination therapy with antidepressants and prokinetics in gastrointestinal dysmotility management.

Interstitial cells of Cajal and human colon motility in health and disease

Our understanding of human colonic motility, and autonomic reflexes that generate motor patterns, has increased markedly through high-resolution manometry. Details of the motor patterns are emerging related to frequency and propagation characteristics that allow linkage to interstitial cells of Cajal (ICC) networks. In studies on colonic motor dysfunction requiring surgery, ICC are almost always abnormal or significantly reduced. However, there are still gaps in our knowledge about the role of ICC in the control of colonic motility and there is little understanding of a mechanistic link between ICC abnormalities and colonic motor dysfunction. This review will outline the various ICC networks in the human colon and their proven and likely associations with the enteric and extrinsic autonomic nervous systems. Based on our extensive knowledge of the role of ICC in the control of gastrointestinal motility of animal models and the human stomach and small intestine, we propose how ICC networks are underlying the motor patterns of the human colon. The role of ICC will be reviewed in the autonomic neural reflexes that evoke essential motor patterns for transit and defecation. Mechanisms underlying ICC injury, maintenance, and repair will be discussed. Hypotheses are formulated as to how ICC dysfunction can lead to motor abnormalities in slow transit constipation, chronic idiopathic pseudo-obstruction, Hirschsprung's disease, fecal incontinence, diverticular disease, and inflammatory conditions. Recent studies on ICC repair after injury hold promise for future therapies.

Dynamic slow-wave interactions in the rabbit small intestine defined using high-resolution mapping

BACKGROUND

The motility in the small intestine is governed in part by myogenic bio-electrical events, known as slow waves. High-resolution multi-electrode mapping has improved our understanding of slow-wave propagation in the small intestine but has been applied in a limited number of in vivo animal studies. This study applied high-resolution mapping to investigate slow waves in the rabbit small intestine.

METHODS

A high-resolution flexible printed circuit board array (256 electrodes; 4 mm spacing) was applied in vivo to the rabbit intestine. Extracellular slow-wave activity was acquired sequentially along the length of the intestine.

KEY RESULTS AND CONCLUSIONS

The majority of the slow waves propagated in the antegrade direction (56%) while retrograde patterns were primarily observed in the distal intestine (29%). Colliding slow-wave events were observed across the length of the small intestine (15%). The interaction of competing pacemakers was mapped in spatiotemporal detail. The frequency and velocity of the slow waves were highest in the duodenum compared to ileum (20.0 ± 1.2 cpm vs 10.5 ± 0.9 cpm, P < 0.001; 14.4 ± 3.4 mm/s vs 12.3 ± 3.4 mm/s; P < 0.05).

INFERENCES

In summary, extracellular serosal slow-wave activity was quantified spatiotemporally along the length of the rabbit intestine. In particular, the study provides evidence toward the presence and interaction of slow-wave pacemakers acting along the small intestine and how they may contribute to the slow-wave frequency gradient along the length of the intestine.

Effect of Chaihu Shugan Powder-Contained Serum on Glutamate-Induced Autophagy of Interstitial Cells of Cajal in the Rat Gastric Antrum

Gastrointestinal (GI) motility disorder is caused by excessive autophagy of the interstitial cells of Cajal (ICC). Chaihu Shugan Powder (CSP) is a traditional Chinese medicine with therapeutic benefits in GI motility disorders; however, the underlying mechanism of its therapeutic effect in GI disorders, especially autophagy of ICC, remains unclear. Thus, this study investigated the effects of CSP-contained serum on glutamate-induced autophagy in rat gastric ICC, exploring its underlying mechanism. In vitro cultured rat stomach ICC were identified by fluorescence microscopy and then stimulated with glutamate (5 mmol/L) for 3 h to establish the autophagy model. These cells were then treated with 10% CSP-containing serum or the autophagy inhibitor 3-methyladenine (3-MA; 5 mmol/L) for 24 h. The control group was cultured with only 10% serum containing physiological saline. The viability of ICC was measured by the CCK-8 assay. The ultrastructure and autophagosomes of ICC were observed using transmission electron microscopy. LC3 expression was detected by immunofluorescence, and LC3, Beclin1, Bcl2, and PI3KC3 expression was detected by western blot analysis. Transmission electron microscopy showed abundant endoplasmic reticulum, mitochondria, and other organelles in the control group, whereas the cells in the autophagy model control group had clear autophagic vacuoles, which were not apparent in both CSP and 3-MA groups. ICC viability was significantly increased by CSP and 3-MA interventions (P < 0.01), accompanied by a decrease in LC3 fluorescence (P < 0.01). Moreover, the expression levels of LC3II/I, Beclin1, and PI3KC3 were significantly decreased (all P < 0.01) with CSP and 3-MA treatment, while Bcl2 expression level was higher than that of the model group (P < 0.01). Thus, CSP can reduce autophagic damage by enhancing Bcl2 expression and downregulating the expression of LC3, Beclin1, and PI3KC3 to protect ICC. These results highlight the potential of CSP in the treatment of GI motility disorders.

Investigation of autophagy and differentiation of myenteric interstitial cells of Cajal in the pathogenesis of gastric motility disorders in rats with functional dyspepsia

Interstitial cells of Cajal (ICC), especially myenteric interstitial cells of Cajal (ICC-MY), are key to gastrointestinal motility. However, their role in the pathogenesis of functional dyspepsia (FD) is unclear. Therefore, autophagy and differentiation of ICC-MY were investigated to elucidate the pathogenesis of gastric motility disorder in FD. FD model was induced by chronic stress via tail clamping in rats, which was assessed by the vital signs of rats, gastric emptying rate result, and histology. The ultrastructure of ICC-MY was examined using transmission electron microscope. In ICC-MY, changes in autophagic biomarkers (Beclin1 and LC3B) and differentiation biomarkers (c-kit and SCF) were evaluated with in situ hybridization, quantitative real time PCR, immunofluorescence, and Western blot, respectively. The FD model was successfully induced in rats, as evidenced by the abnormal vital signs (such as loss of appetite, liquid excreta, less activity, and slower weight gain), the decrease in gastric emptying rates, and little pathological change in gastric antrum tissue. Compared with the control group, FD caused increased organelle denaturation or reduction and increase in vacuolization. FD also promoted generation of autophagosomes in ICC-MY. Moreover, increased the expression of Beclin1 and LC3B, but decreased expression of c-kit and SCF. Excessive autophagy and abnormal differentiation of ICC-MY may contribute to the pathogenesis of gastric motility disorder in FD.

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.

Nitric oxide-mediated injury of interstitial cells of Cajal and intestinal dysmotility under endotoxemia of mice

Gastrointestinal dysmotility is frequently observed under septic conditions, yet its precise mechanisms remain to be elucidated. In this study, we have investigated the mechanisms of intestinal dysmotility by lipopolysaccharides (LPS) and the role of the interstitial cells of Cajal (ICCs) in motility disorders using a mouse endotoxin model. The injection of LPS caused time- and dose-dependent decreases in the intestinal contractility, which was associated with similar time- and dose-dependent decreases in the number of KIT-positive fibroblast-like cells located in the intermuscular layer. iNOS inhibitors, L-NAME and aminoguanidine (AG), but not 7-nitroindazole (7NI), a specific nNOS inhibitor, inhibited the LPS-induced decreases in both the contractility and the number of KIT-positive cells. A spontaneous NO releaser, FK409, not only diminished spontaneous electrical potential and phasic contractions, but also decreased the number of KIT-positive cells. Pretreatment with gadolinium inhibited the activation of macrophages and the induction of iNOS in intestinal resident macrophages, and restored the number of KIT-positive cells and intestinal contractions. These results suggested that NO produced from intestinal macrophages via iNOS induced by LPS, may be involved in the ICCs injury and intestinal dysmotility under septic conditions.

Autoimmunity Links Vinculin to the Pathophysiology of Chronic Functional Bowel Changes Following Campylobacter jejuni Infection in a Rat Model

BACKGROUND

Acute gastroenteritis can precipitate irritable bowel syndrome (IBS) in humans. Cytolethal distending toxin is common to all pathogens causing gastroenteritis. Its active subunit, CdtB, is associated with post-infectious bowel changes in a rat model of Campylobacter jejuni infection, including small intestinal bacterial overgrowth (SIBO).

AIM

To evaluate the role of host antibodies to CdtB in contributing to post-infectious functional sequelae in this rat model.

METHODS

Ileal tissues from non-IBS human subjects, C. jejuni-infected and control rats were immunostained with antibodies to CdtB, c-Kit, S-100, PGP 9.5 and vinculin. Cytosolic and membrane proteins from mouse enteric neuronal cell lysates were immunoprecipitated with anti-CdtB and analyzed by mass spectrometry. ELISAs were performed on rat cardiac serum using CdtB or vinculin as antigens.

RESULTS

Anti-CdtB antibodies bound to a cytosolic protein in interstitial cells of Cajal (ICC) and myenteric ganglia in C. jejuni-infected and naïve rats and human subjects. Mass spectrometry identified vinculin, confirmed by co-localization and ELISAs. Anti-CdtB antibodies were higher in C. jejuni-infected rats (1.27 ± 0.15) than controls (1.76 ± 0.12) (P < 0.05), and rats that developed SIBO (2.01 ± 0.18) vs. rats that did not (1.44 ± 0.11) (P = 0.019). Vinculin expression levels were reduced in C. jejuni-infected rats (0.058 ± 0.053) versus controls (0.087 ± 0.023) (P = 0.0001), with greater reductions in rats with two C. jejuni infections (P = 0.0001) and rats that developed SIBO (P = 0.001).

CONCLUSIONS

Host anti-CdtB antibodies cross-react with vinculin in ICC and myenteric ganglia, required for normal gut motility. Circulating antibody levels and loss of vinculin expression correlate with number of C. jejuni exposures and SIBO, suggesting that effects on vinculin are important in the effects of C. jejuni infection on the host gut.

Telocytes are reduced during fibrotic remodelling of the colonic wall in ulcerative colitis

Ulcerative colitis (UC) is characterized by chronic relapsing intestinal inflammation finally leading to extensive tissue fibrosis and resulting in a stiff colon unable to carry out peristalsis or to resorb fluids. Telocytes, a peculiar type of stromal cells, have been recently identified in the human gastrointestinal tract. Several roles have been proposed for telocytes, including mechanical support, intercellular signalling and modulation of intestinal motility. The aim of the present work was to investigate the presence and distribution of telocytes in colonic specimens from UC patients compared with controls. Archival paraffin-embedded samples of the left colon from UC patients who underwent elective bowel resection and controls were collected. Tissue sections were stained with Masson's trichrome to detect fibrosis. Telocytes were identified by CD34 immunohistochemistry. In early fibrotic UC cases, fibrosis affected the muscularis mucosae and submucosa, while the muscularis propria was spared. In advanced fibrotic UC cases, fibrosis extended to affect the muscle layers and the myenteric plexus. Few telocytes were found in the muscularis mucosae and submucosa of both early and advanced fibrotic UC colonic wall. In the muscle layers and myenteric plexus of early fibrotic UC, telocytes were preserved in their distribution. In the muscularis propria of advanced fibrotic UC, the network of telocytes was reduced or even completely absent around smooth muscle bundles and myenteric plexus ganglia, paralleling the loss of the network of interstitial cells of Cajal. In UC, a loss of telocytes accompanies the fibrotic remodelling of the colonic wall and might contribute to colonic dysmotility.

Histopathologic findings in patients with idiopathic megacolon: a comparison between dilated and non-dilated loops

BACKGROUND

Idiopathic megacolon (IMC) is an intractable motility disorder in which chronic symptoms of colonic dysmotility appear with no mechanical cause. Although a pathological analysis is essential to understand the mechanism of IMC, no study has compared the histopathologic findings between dilated and non-dilated loops in IMC cases, and little is known about the proportion of each disease subtype.

METHODS

Fifty-three full-thickness samples (dilated loops, n = 31; non-dilated loops, n = 22) from 31 IMC cases and 16 samples (dilated loops; n = 8, non-dilated loops; n = 8) from eight controls were collected. All the samples were stained with hematoxylin-eosin (HE), Hu C/D antibody, and CD117 antibody to assess degenerative myopathy, degenerative neuropathy, inflammatory neuropathy, hypoganglionosis, and mesenchymopathy according to the London Classification. Findings of the dilated and non-dilated loop samples were compared, and the proportions of each subtype were analyzed.

KEY RESULTS

Based on a control study, <60 ganglion cells/cm was defined as hypoganglionosis in our series. Myopathy was observed in 11 patients (35.5%), neuropathy was in 19 patients (61.3%), and mesenchymopathy was in 10 patients (32.2%). An overlap between subtypes was observed in some cases. Surprisingly, the non-dilated loop samples exhibited very similar histopathologic abnormalities to those observed in the dilated loop samples in most cases.

CONCLUSIONS & INFERENCES

Our study is the first to compare the histopathologic findings between dilated and non-dilated loops in IMC patients. Histopathologic abnormalities precede the clinical manifestation of IMC, and may consequently lead to gradual colonic dilatation; however, detailed mechanism including dilation triggering factor needs further elucidation.

Review article: the assessment and management of chronic severe gastrointestinal dysmotility in adults

BACKGROUND

The characterisation and management of chronic severe gastrointestinal (GI) dysmotility are challenging. It may cause intestinal failure requiring home parenteral nutrition (HPN).

AIMS

To review the presentation, aetiology, characterisation, management and outcome of chronic severe GI dysmotility, and to suggest a pragmatic management algorithm.

METHODS

PubMed search was performed up to December 2012 using appropriate search terms, restricted to human articles and reviewed for relevance. Segmental dysmotility, acute ileus, functional syndromes and non-English articles were excluded. Evidence and recommendations were evaluated using the GRADE system.

RESULTS

In total, 721 relevant articles were reviewed. A coherent and definitive picture is hampered by overlapping classification systems using multi-modal characterisation methods, subject to pitfalls and some requiring further validation. The literature is confined to case series with no randomised trials. Fewer than 20% undergo full thickness jejunal biopsy, which are otherwise labelled idiopathic. However, in studies with up to 80% biopsy rates, neuromuscular abnormalities may be found in 90%. Between 14% and 50% will require HPN, comprising 8-14% of all HPN patients, of which 2/3 are primary/idiopathic and 1/3 secondary, with scleroderma being the leading secondary cause. Ten-year  mortality ranges from 13% to 35% and is worst in elderly scleroderma patients. Management includes limited treatments for secondary causes, prokinetics, symptom palliation, psychological support, nutrition, hydration and judicious surgery.

CONCLUSIONS

Severe dysmotility often remains idiopathic. It is rarely possible to alter disease trajectory; consequently, prognosis may be poor. Multi-disciplinary teams in a specialist setting can improve outcomes. Graded recommendations are enumerated and a pragmatic algorithm is suggested.

Alterations of the interstitial cells of Cajal and the microstructure of the gastrointestinal tract in KIT distal kinase mutant mice

The development and maintenance of interstitial cells of Cajal (ICC) are closely associated with SCF/KIT signal activity. In this study, we evaluate the distribution of ICC in KIT distal kinase domain mutant mice (Wads) and determine whether the loss-of-function mutations in KIT easily lead to gastrointestinal (GI) disorders. ICC were examined by anti-KIT immunohistochemistry and western blotting. The GI microstructure of wild-type (WT) and Wads mice in normal intestines and incomplete intestinal obstruction was evaluated by hematoxylin and eosin staining. The results in Wads(m/m) mice were as follows. Myenteric ICC were obviously decreased in the stomach and colon and were totally absent in the small intestine. Intramuscular ICC were nearly absent in the stomach and irregularly distributed in the colon. Moreover, the smooth muscle thickness of the small intestine was increased 1.3-fold in Wads(m/m), compared to WT and Wads(m/+) mice and the diameter of the intestinal lumen was also enlarged in Wads(m/m) mice. When constructing an incomplete intestinal obstruction model, the extent of distention involved was greater in Wads mice (1.6-fold in Wads(m/+) mice and 1.8-fold in Wads(m/m) mice vs. WT mice). Meanwhile, the intestinal lumen expansion and decrease in ICC were more pronounced in Wads mice than in WT mice. Our results suggest that the KIT distal kinase domain mutation leads to an ICC loss in a subtype and location-specific pattern in Wads(m/m) mice. The injury of the KIT signaling in mutant mice results in more serious pathological manifestations after being exposed to pathogenic factors.

Effect of repeated Campylobacter jejuni infection on gut flora and mucosal defense in a rat model of post infectious functional and microbial bowel changes

BACKGROUND

Campylobacter jejuni infection is a leading cause of gastroenteritis and post infectious irritable bowel syndrome (PI-IBS). Unanswered questions include the role of cytokines, effects on gut flora, and why IBS is not more prevalent in countries with higher gastroenteritis rates. Therefore, we determined the effects of early and repeat C. jejuni infections on post infectious phenotypes, gut flora, and cytokine levels in a rat model of functional bowel and microbial changes.

METHODS

Sprague-Dawley rats were gavaged with 10(8)  cfu C. jejuni as juveniles and again as adults (J+/A+), as adults only (J-/A+), or vehicle (controls). Stool consistency during acute colonization, post infectious stool wet weight, total bacteria and Methanobrevibacter smithii levels in bowel segments, and ileal cytokines were evaluated.

KEY RESULTS

C. jejuni colonization was longer for first exposures as juveniles (43.4 ± 1.7 days) vs. adults (30.4 ± 3.5 days) (P < 0.01) and shortest for second exposures (10.5 ± 1.7 days, P < 0.05). Small intestinal bacterial overgrowth (SIBO) was more prevalent in J+/A+ (47%) than J-/A+ rats (26%) (P = 0.019), but J-/A+ rats had greater stool consistency alterations (P < 0.01). Ileal β-defensin 2, TLR-4, IL-8, and β-defensin 6 levels were increased in J-/A+ rats and further increased in J+/A+ rats; TNF-α was highest and IL6 lowest in J-/A+ rats. Total bacteria increased, and M. smithii decreased, with successive infections.

CONCLUSIONS & INFERENCES

We conclude that C. jejuni infection results in long-term alterations in small bowel flora, including methanogens. Mucosal defense mediators appear related to the number of infections, but not to SIBO development or the development of functional bowel phenotypes.

Cells derived from the coelomic epithelium contribute to multiple gastrointestinal tissues in mouse embryos

Gut mesodermal tissues originate from the splanchnopleural mesenchyme. However, the embryonic gastrointestinal coelomic epithelium gives rise to mesenchymal cells, whose significance and fate are little known. Our aim was to investigate the contribution of coelomic epithelium-derived cells to the intestinal development. We have used the transgenic mouse model mWt1/IRES/GFP-Cre (Wt1^cre) crossed with the Rosa26R-EYFP reporter mouse. In the gastrointestinal duct Wt1, the Wilms’ tumor suppressor gene, is specific and dynamically expressed in the coelomic epithelium. In the embryos obtained from the crossbreeding, the Wt1-expressing cell lineage produces the yellow fluorescent protein (YFP) allowing for colocalization with differentiation markers through confocal microscopy and flow cytometry. Wt1^cre-YFP cells were very abundant throughout the intestine during midgestation, declining in neonates. Wt1^cre-YFP cells were also transiently observed within the mucosa, being apparently released into the intestinal lumen. YFP was detected in cells contributing to intestinal vascularization (endothelium, pericytes and smooth muscle), visceral musculature (circular, longitudinal and submucosal) as well as in Cajal and Cajal-like interstitial cells. Wt1^cre-YFP mesenchymal cells expressed FGF9, a critical growth factor for intestinal development, as well as PDGFRα, mainly within developing villi. Thus, a cell population derived from the coelomic epithelium incorporates to the gut mesenchyme and contribute to a variety of intestinal tissues, probably playing also a signaling role. Our results support the origin of interstitial cells of Cajal and visceral circular muscle from a common progenitor expressing anoctamin-1 and SMCα-actin. Coelomic-derived cells contribute to the differentiation of at least a part of the interstitial cells of Cajal.

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.

Platelet-derived growth factor receptor α (PDGFRα)-expressing "fibroblast-like cells" in diabetic and idiopathic gastroparesis of humans

BACKGROUND

Emerging evidence suggests that "fibroblast-like cells" (FLC) may play a role in the regulation of gastrointestinal (GI) motor function. FLC are ultrastructurally distinct from other interstitial cells, including interstitial cells of Cajal (ICC), and express small-conductance Ca(2+) -activated K(+) channels (SK3). In mice, platelet-derived growth factor receptor α (PDGFRα) antibody has also been shown to label FLC. The aims of this study were to determine the morphology and distribution of PDGFRα-immunoreactive (ir) FLC in human gastric muscle and to determine if FLC are altered in gastroparesis, where ICC are reduced.

METHODS

Full thickness gastric body biopsies from five healthy subjects, 10 diabetic, and 10 idiopathic gastroparesis patients were immunolabeled using SK3 and PDGFRα staining for FLC and Kit staining for ICC. Intramuscular FLC and ICC were quantified.

KEY RESULTS

Intramuscular PDGFRα-ir cells had slender cell bodies and long, thin processes and were more abundant in the longitudinal compared with the circular muscle. In the region of myenteric plexus, FLC had smaller, rounder cell bodies with 3-4 processes and formed networks, often around ganglia. All SK3-ir cell structures showed complete overlap with PDGFRα-ir. FLC were in close proximity to ICC, but their cell bodies did not overlap. No differences were seen in the distribution, morphology, or overall numbers of FLC in gastroparesis patients.

CONCLUSIONS & INFERENCES

In conclusion, PDGFRα identifies FLC in human gastric smooth muscle. FLC were not altered in distribution or overall numbers in gastroparesis. Additional studies are required to determine their role in human GI function.

Inflammation and microflora

Irritable bowel syndrome (IBS) is the most common gastrointestinal condition, affecting 10% to 20% of adults in developed countries. Over the last few years, growing evidence has supported a new hypothesis for IBS based on alterations in intestinal bacterial composition. This article reviews the evidence for a bacterial concept in IBS and begins to formulate a hypothesis of how these bacterial systems could integrate in a new pathophysiologic mechanism in the development of IBS. Data suggesting an interaction between this gut flora and inflammation in the context of IBS is also presented.

GLI3 repressor controls functional development of the mouse ureter

Obstructive and nonobstructive forms of hydronephrosis (increased diameter of the renal pelvis and calyces) and hydroureter (dilatation of the ureter) are the most frequently detected antenatal abnormalities, yet the underlying molecular mechanisms are largely undefined. Hedgehog (Hh) proteins control tissue patterning and cell differentiation by promoting GLI-dependent transcriptional activation and by inhibiting the processing of GLI3 to a transcriptional repressor. Genetic mutations that generate a truncated GLI3 protein similar in size to the repressor in humans with Pallister-Hall syndrome (PHS; a disorder whose characteristics include renal abnormalities) and hydroureter implicate Hh-dependent signaling in ureter morphogenesis and function. Here, we determined that Hh signaling controls 2 cell populations required for the initiation and transmission of coordinated ureter contractions. Tissue-specific inactivation of the Hh cell surface effector Smoothened (Smo) in the renal pelvic and upper ureteric mesenchyme resulted in nonobstructive hydronephrosis and hydroureter characterized by ureter dyskinesia. Mutant mice had reduced expression of markers of cell populations implicated in the coordination of unidirectional ureter peristalsis (specifically, Kit and hyperpolarization-activation cation-3 channel [Hcn3]), but exhibited normal epithelial and smooth muscle cell differentiation. Kit deficiency in a mouse model of PHS suggested a pathogenic role for GLI3 repressor in Smo-deficient embryos; indeed, genetic inactivation of Gli3 in Smo-deficient mice rescued their hydronephrosis, hydroureter, Kit and Hcn3 expression, and ureter peristalsis. Together, these data demonstrate that Hh signaling controls Kit and Hcn3 expression and ureter peristalsis.

Ulcerative colitis: ultrastructure of interstitial cells in myenteric plexus

Interstitial cells of Cajal (ICC) are key regulatory cells in the gut. In the colon of patients with severe ulcerative colitis (UC), myenteric ICC had myoid ultrastructural features and were in close contact with nerve terminals. In all patients as opposed to controls, some ICC profiles showed degenerative changes, such as lipid droplets and irregular vacuoles. Nerve terminals often appeared swollen and empty. Glial cells, muscle cells, and fibroblast-like cells (FLC) showed no alterations. FLC enclosed macrophages (MLC), which were in close contact with naked axon terminals. The organization and cytological changes may be of pathophysiological significance in patients with UC.

Reduction of interstitial cells of Cajal in esophageal atresia

OBJECTIVES

Postrepair esophageal dysmotility and gastroesophageal reflux are well-known consequences in patients with congenital esophageal atresia (EA) with or without distal tracheoesophageal fistula (TEF). The interstitial cells of Cajal (ICC), considered the intestinal pacemaker, are altered in congenital diseases with abnormal peristalsis, but no data are available for EA. Therefore, presence and maturation of ICC was verified in EA-TEF newborns.

PATIENTS AND METHODS

Fifteen full-term neonates underwent repair of EA-TEF. Control specimens were from 10 newborns who died of nonesophageal diseases. Specimens from upper pouch, fistula, proximal, and distal esophagus were processed for hematoxylin and eosin, c-kit immunohistochemistry for ICC identification, and transmission electron microscopy. Frequency of c-kit-positive cells was evaluated in 20 fields per slide using a visual score (absent, very low, low, medium, high, very high). Morphocytometry and statistical analysis were also performed.

RESULTS

In the proximal normal esophagus, ICC frequency was very high (3 cases), high (5), and medium (2); distally, it was high (4) and medium (6). In EA-TEF upper pouch, it was high (2) and medium (13); in the fistula, it was medium (5), low (6), very low (3), and absent (1). Morphocytometry confirmed these results. Comparison between pouch and fistula versus proximal and lower esophagus, respectively, showed statistically significant differences. Transmission electron microscopy demonstrated ICC immaturity in EA-TEF.

CONCLUSIONS

The significant lower ICC density in EA-TEF is in favor for the pathogenesis of esophageal dysmotility frequently observed in such patients.

ICC density predicts bacterial overgrowth in a rat model of post-infectious IBS

AIM: To investigate the interstitial cells of Cajal (ICC) number using a new rat model.

METHODS: Sprague-Dawley rats were assigned to two groups. The first group received gavage with Campylobacter jejuni (C. jejuni) 81-176. The second group was gavaged with placebo. Three months after clearance of Campylobacter from the stool, precise segments of duodenum, jejunum, and ileum were ligated in self-contained loops of bowel that were preserved in anaerobic bags. Deep muscular plexus ICC (DMP-ICC) were quantified by two blinded readers assessing the tissue in a random, coded order. The number of ICC per villus was compared among controls, Campylobacter recovered rats without small intestinal bacterial overgrowth (SIBO), and Campylobacter recovered rats with SIBO.

RESULTS: Three months after recovery, 27% of rats gavaged with C. jejuni had SIBO. The rats with SIBO had a lower number of DMP-ICC than controls in the jejunum and ileum. Additionally there appeared to be a density threshold of 0.12 DMP-ICC/villus that was associated with SIBO. If ileal density of DMP-ICC was < 0.12 ICC/villus, 54% of rats had SIBO compared to 9% among ileal sections with > 0.12 (P < 0.05). If the density of ICC was < 0.12 DMP-ICC/villus in more than one location of the bowel, 88% of these had SIBO compared to 6% in those who did not (P < 0.001).

CONCLUSION: In this post-infectious rat model, the development of SIBO appears to be associated with a reduction in DMP-ICC. Further study of this rat model might help understand the pathophysiology of post-infectious irritable bowel syndrome.

Depopulation of interstitial cells of cajal in chagasic megacolon: towards tailored surgery?

BACKGROUND: The mechanism of constipation in patients with Chagasic megacolon remains partially explained. In these patients, it was recently demonstrated a reduction in the population of interstitial cells of Cajal. AIM: To evaluate density of Cajal cells in the surgically resected colon of Chagasic patients in comparison to control patients, and to verify possible association between preoperative and postoperative bowel function of Chagasic patients and colonic cell count. METHOD: Sixteen patients with Chagasic megacolon were operated on. Clinical pre- and post-operative evaluation using the Cleveland Clinic Constipation Score was undertaken. Resected colons were examined. Cajal cells were identified by immunohistochemistry using anti-CD117 antibody. The mean cell number was compared to resected colons from 16 patients with non-obstructive sigmoid cancer. Association between pre-and post-operative constipation scores and cell count for megacolon patients was evaluated using the Pearson coefficient correlation test (r). RESULTS: A reduced number of Cajal cells [cells per field: 2.84 (0-6.6) vs. 9.68 (4.3-13) - p<0.001] was observed in the resected colon of Chagasic patients when compared to colon cancer patients. No correlation between constipation score before (r=-0.205; p=0.45) or after surgery (r=0,291; p=0.28) and cell count for megacolon patients was observed. CONCLUSIONS: Patients with Chagasic megacolon display marked reduction of interstitial cells of Cajal when compared to non-Chagasic patients. An association of constipation severity and Cajal cells depopulation in Chagasic megacolon could not be demonstrated.

The expression of Cajal cells at the obstruction site of congenital pelviureteric junction obstruction and quantitative image analysis

OBJECTIVE

The study aimed to analyze the expression and significance of interstitial cells of Cajal (ICC) at the obstruction site of congenital pelviureteric junction obstruction (PUJO).

METHODS

Specimens of the strictured segment of the PUJ were obtained from 24 patients who were diagnosed to have PUJO (without aberrant vessels and adhesive band compression of ureteral junction) intraoperatively. In the control group, PUJ specimens were taken from 21 patients who had Wilms' tumor. Pelviureteric junction tissues were confirmed to be free of tumor invasion by histology. Immunohistochemistry with c-kit antibody was performed to detect the expression of ICC in specimens of the 2 groups. Quantitative analysis was made using image analysis technique and statistical analysis was carried out.

RESULTS

Immunoreactivity to ICC was predominantly detected in the muscle layers of PUJ. The mean area of ICC expression in the PUJO group was 14.86 +/- 1.37 x 10(4)microm(2) , which was lower than that in the control group (16.80 +/- 1.68) x 10(4)microm(2) (P < .01). The mean density of ICC expression in the PUJO was 0.207 +/- 0.020, which was also lower than that in the control group (0.262 +/- 0.026) (P < .05).

CONCLUSIONS

A reduction of the number of ICC may play an important role in the etiology and pathogenesis of PUJO.

Gastrointestinal neuromuscular pathology: guidelines for histological techniques and reporting on behalf of the Gastro 2009 International Working Group

The term gastrointestinal neuromuscular disease describes a clinically heterogeneous group of disorders of children and adults in which symptoms are presumed or proven to arise as a result of neuromuscular, including interstitial cell of Cajal, dysfunction. Such disorders commonly have impaired motor activity, i.e. slowed or obstructed transit with radiological evidence of transient or persistent visceral dilatation. Whilst sensorimotor abnormalities have been demonstrated by a variety of methods in these conditions, standards for histopathological reporting remain relatively neglected. Significant differences in methodologies and expertise continue to confound the reliable delineation of normality and specificity of particular pathological changes for disease. Such issues require urgent clarification to standardize acquisition and handling of tissue specimens, interpretation of findings and make informed decisions on risk-benefit of full-thickness tissue biopsy of bowel or other diagnostic procedures. Such information will also allow increased certainty of diagnosis, facilitating factual discussion between patients and caregivers, as well as giving prognostic and therapeutic information. The following report, produced by an international working group, using established consensus methodology, presents proposed guidelines on histological techniques and reporting for adult and paediatric gastrointestinal neuromuscular pathology. The report addresses the main areas of histopathological practice as confronted by the pathologist, including suction rectal biopsy and full-thickness tissue obtained with diagnostic or therapeutic intent. For each, indications, safe acquisition of tissue, histological techniques, reporting and referral recommendations are presented.

Absence of the interstitial cell of Cajal network in mitochondrial neurogastrointestinal encephalomyopathy

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal-recessive multisystemic disorder with predominant gastrointestinal involvement, presenting with variable degrees of gut dysmotility up to frank chronic intestinal pseudoobstruction. Despite major advances in understanding its basic molecular pathogenesis in recent years, the distinct mechanisms and pathoanatomical substrate underlying MNGIE-associated gastrointestinal dysmotility are still widely unknown. As yet, though their critical role in proper gastrointestinal transit in terms of spontaneous pacemaker activity and enteric neurotransmission is well established, the population of the interstitial cells of Cajal (ICC) has not been investigated in MNGIE. Therefore, we examined small bowel samples of a well-characterized MNGIE patient by using conventional histology and immunohistochemistry techniques. The ICC network was studied by immunohistochemistry for the tyrosine kinase Kit (CD117), known to reliably detect ICCs, while mucosal mast cells served as an internal and normal small bowel specimen as external controls. At a light microscopic level, no gross structural alteration of the bowel wall composition and its neuromuscular elements was noted. However, a complete absence of Kit immunoreactive cells could be demonstrated in regions where ICCs are normally abundant, while internal and external controls retained strong Kit positivity. In conclusion, our preliminary results provide a first evidence for an alteration of the ICC network in MNGIE, and support the notion that ICC loss might be an early pathogenetic event in MNGIE-associated gut motor dysfunction before significant myopathic and/or neuropathic structural changes occur.

Long-term outcome of chronic intestinal pseudo-obstruction adult patients requiring home parenteral nutrition

OBJECTIVES

Chronic intestinal pseudo-obstruction (CIPO) is a rare, disabling disorder responsible for motility-related intestinal failure. Because it induces malnutrition, CIPO is a significant indication for home parenteral nutrition (HPN). The objective of the study was to evaluate long-term outcome of CIPO patients requiring HPN during adulthood.

METHODS

In total, 51 adult CIPO patients (18 men/33 women, median age at symptom occurrence 20 (0-74) years, 34/17 primary/secondary CIPO) followed up at our institution for HPN management between 1980 and 2006 were retrospectively studied for survival and HPN dependence rates using univariate and multivariate analysis.

RESULTS

Follow-up after diagnosis was 8.3 (0-29) years. Surgery was required in 84% of patients. The number of interventions was 3 +/- 3 per patient (mean +/- s.d.), leading to short bowel syndrome in 19 (37%) patients. Actuarial survival probability was 94, 78, 75, and 68% at 1, 5, 10, and 15 years, respectively. Multivariate analysis showed that lower mortality was associated with the ability to restore oral feeding at baseline (hazard ratio (HR) = 0.2 (0.06-0.65), P = 0.008) and symptom occurrence before the age of 20 years (HR=0.18 (0.04-0.88), P = 0.03). Higher mortality was associated with systemic sclerosis (HR=10.4 (1.6-67.9), P = 0.01). Actuarial HPN dependence was 94, 75, and 72% at 1, 2, and 5 years, respectively.

CONCLUSIONS

In this large cohort of CIPO adult patients with severe intestinal failure, i.e., those requiring HPN, we found a higher survival probability than previously reported. These results should be taken into account when considering intestinal transplantation.

Quantitative evaluation of myenteric ganglion cells in normal human left colon: implications for histopathological analysis

The analysis of myenteric neurons is becoming increasingly important for the assessment of enteric nervous system injury and degeneration occurring in motor disorders of the gut. Limited information is presently available on the quantitative estimation of myenteric neurons and glial cells in paraffin-embedded colonic sections; additional data would be useful for diagnostic purposes. In this morphometric study, we performed immunohistochemistry to count myenteric neurons and glial cells in paraffin sections of human colon. Serial cross sections of formalin-fixed paraffin-embedded full-thickness normal human left colon (n = 10, age-range: 50-72 years) were examined. HuC/D and S100beta antigens were found to be the best markers for the detection of neurons and glial cells, respectively. Significant correlations were noted between the numbers of neurons/glial cells and the respective myenteric ganglion areas. These findings suggest that HuC/D-S100beta-immunostained paraffin cross sections of human colon can be regarded as valuable tools for the quantitative estimation of myenteric neurons and glial cells. Based on the present method, only a limited number of paraffin sections are needed for reliable quantitative assessments of myenteric ganglion cells, thus allowing fast and simple approaches in the settings of the histopathological diagnosis of colonic motility disorders and retrospective evaluations of pathological archival tissue specimens.

Phenotypic alteration of interstitial cells of Cajal in idiopathic sigmoid megacolon

BACKGROUND

Interstitial cells of Cajal (ICCs) are detected as a pacemaker of gastrointestinal movement and express c-kit and CD34. Recently, ICCs have implicated pathogenesis in several human diseases presenting gastrointestinal motor dysfunction. This study was performed to clarify the role of ICCs in idiopathic sigmoid megacolon using histological and immunohistochemical examinations.

METHODS

Four adult patients with idiopathic sigmoid megacolon and 11 controls were studied. Histology and immunocytochemistry using NSE, S100, c-kit, and CD34 were performed in conjunction with quantitative analysis using the public domain NIH image program.

RESULTS

Little histological change in neuromuscular structures in megacolon was observed. Immunohistochemistry demonstrated remarkable decrease of c-kit expressing ICCs without reduction of CD34 expression in the similar interstitial cell population. This observation was further supported by quantitative assessment using public domain NIH image program.

CONCLUSIONS

A specific downregulation of c-kit in ICCs may be a cause of idiopathic sigmoid megacolon in adults.

Assessing interstitial cells of Cajal in slow transit constipation using CD117 is a useful diagnostic test

Slow transit constipation (STC) is a colonic motility disorder that is characterized by measurably delayed movement of stools through the colon. The pathophysiology of STC is unclear and both the interstitial cells of Cajal (ICC) and cells of the enteric nervous system are believed to play an important role. The aim of this study was to compare the number and distribution of ICC and cells of the enteric nervous system in patients with a control group by means of immunohistochemistry. Formalin-fixed paraffin-embedded colonic sections were obtained from 15 patients, aged between 23 and 52 (mean age=37 y), who underwent colectomy for STC. Forty-five cases of normal colon from age and sex-matched nonobstructive colorectal cancer patients were selected as controls. By using c-kit (CD117) and PGP 9.5 immunohistochemical studies, ICC and enteric neurofilaments were demonstrated, respectively. The number of cells were counted under 40 x high-power field (HPF) in 3 layers of the colonic muscularis propria, that is, the inner circular muscle layer, the myenteric plexus, and the outer longitudinal muscle layer in both test and control groups. The mean number of ICC and enteric neurofilaments were significantly reduced in all 3 layers of the muscularis propria from STC patients compared with controls. This reduction was most significant in the inner circular muscle layer (P<0.0001). A cutoff value of 7 ICC per HPF in the inner circular muscle layer can be used as a further confirmation to the clinical diagnosis of STC in resected specimens.

Alterations in the density of interstitial cells of Cajal in achalasia

The aim of this study was to assess the quantity of interstitial cells of Cajal (ICC) in the lower esophageal sphincter (LES) in achalasia. LES muscle was obtained from 11 achalasia and nine esophageal cancer (control) patients during surgery. Immunohistochemistry was performed and average cell counts per high-power field (HPF) were obtained. Overall, more ICC were observed in achalasia (median = 14.0 cells/HPF; range = 0-22.6 cells/HPF) as compared with controls (median = 6.2 cells/HPF; range = 1.6-10.8 cells/HPF) (P = 0.047). There were two subsets of findings within the achalasia group: 8/11(73%) had an increased quantity of ICC (median = 17.1 cells/HPF; range = 11.6-22.6; P = 0.015) as compared with controls, whereas the remaining 3/11(27%) had a paucity of ICC (median = 0 cells/HPF; range = 0-2; P = 0.02). ICC levels were positively correlated with age of the patient (P = 0.043). Our study demonstrates that subsets of abnormal ICC levels are observed in idiopathic achalasia of the esophagus.

Effect of stem cell factor on colon interstitial cells of Cajal in murine with diabetes mellitus

AIM: To investigated whether exogenous stem cell factor (SCF) can improve the diabetes-associated depletion of interstitial cells of Cajal (ICC) in mice with diabetes mellitus (DM).

METHODS: DM mice were intraperitoneally injected with streptozocin (STZ) to induce an experimental model. Male C57/BL6 mice were randomly divided into control group, DM group and DM + SCF group. The mice in DM + SCF group were given exogenous SCF (0.2 µg/kg per day, ip) for 6 wk, and the mice in control group and DM group were given the same amount of phosphate buffer (pH = 7.4). All the mice were sacrificed after 6 wk. ICC changes in the distal colon were assessed by immunohistochemistry, transmission electron microscopy and Western blot, and SCF expression in the distal colon was analyzed by Western blot.

RESULTS: The expression of SCF in the distal colon was significantly reduced in DM group as compared with that in the control group (178.97 ± 13.51 vs 200.25 ± 16.48, P < 0.05), accompanied with the depletion (72 ± 10 vs 102 ± 12, P < 0.05) and microscopic lesions of ICC in the distal colon. The expression of SCF in the distal colon was increased in DM + SCF group (210.14 ± 11.8, P < 0.05), along with the dramatic improvement of ICC quantity (87 ± 10, P < 0.05) and ultrastructure in the distal colon as compared with those in DM group.

CONCLUSION: Exogenous SCF may improve the DM-associated depletion of colon ICC.

CD34-positive interstitial cells of the human detrusor

Interstitial cells of Cajal (ICC) are well described in the bowel wall. They are c-kit positive and play a role as pacemaker cells. Similar c-kit-positive cells have recently been described in the human bladder. The aim of this study was to characterize interstitial cells of the bladder detrusor using a panel of antibodies directed against CD117/c-kit, CD34, CD31, S100, tryptase, neurofilament, NSE, Factor-VIII and GFAP. A striking finding was an interstitial type of cell which is CD34 immunoreactive (CD34-ir) but CD117/c-kit negative. The cells have a tentacular morphology, enveloping and intermingling with individual muscle fasicles. Morphologically and immunohistochemically, they show no neurogenic, endothelial or mast cell differentiation. Transmission electron microscopy (TEM) showed the presence of interstitial cells with a round-to-oval nucleus, sparse perinuclear cytoplasm and long flattened processes, ramifying primarily in a bipolar fashion. Using immunoelectron microscopy (I-TEM) it was possible to view CD34 gold labelling of cells corresponding to interstitial cells. Although similar CD34-positive cells have been demonstrated in the bowel wall, they have never been described in the detrusor. The ontogeny and function of CD34-ir, a kit-negative cell, is unknown, but it may be involved in smooth muscle contraction.

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.

Intestinal pseudo-obstruction: An uncommon condition with heterogeneous etiology and unpredictable outcome

Intestinal pseudo-obstruction (IPO) either acute or chronic is a condition including features of intestinal ileus in absence of mechanical obstruction. Our paper presents such a rare case of idiopathic IPO in a 53-year-old male patient with recurrent episodes of pseudo-obstruction, which were successfully resolved by anticholinesterase agents, motilin agonists or colonic decompression. However, the patient finally underwent total colectomy. Huge colonic dilatation was identified intraoperatively, while histology showed a neuropathic variant of chronic intestinal pseudo-obstruction. Etiologic mechanisms and current therapeutic methods are reviewed in this paper, which concludes that IPO is a condition in which conservative treatment usually fails. Total colectomy with ileoanal pouch may be the only solution in these situations.

Are interstitial cells of Cajal plurifunction cells in the gut?

The proposed functions of the interstitial cells of Cajal (ICC) are to 1) pace the slow waves and regulate their propagation, 2) mediate enteric neuronal signals to smooth muscle cells, and 3) act as mechanosensors. In addition, impairments of ICC have been implicated in diverse motility disorders. This review critically examines the available evidence for these roles and offers alternate explanations. This review suggests the following: 1) The ICC may not pace the slow waves or help in their propagation. Instead, they may help in maintaining the gradient of resting membrane potential (RMP) through the thickness of the circular muscle layer, which stabilizes the slow waves and enhances their propagation. The impairment of ICC destabilizes the slow waves, resulting in attenuation of their amplitude and impaired propagation. 2) The one-way communication between the enteric neuronal varicosities and the smooth muscle cells occurs by volume transmission, rather than by wired transmission via the ICC. 3) There are fundamental limitations for the ICC to act as mechanosensors. 4) The ICC impair in numerous motility disorders. However, a cause-and-effect relationship between ICC impairment and motility dysfunction is not established. The ICC impair readily and transform to other cell types in response to alterations in their microenvironment, which have limited effects on motility function. Concurrent investigations of the alterations in slow-wave characteristics, excitation-contraction and excitation-inhibition couplings in smooth muscle cells, neurotransmitter synthesis and release in enteric neurons, and the impairment of the ICC are required to understand the etiologies of clinical motility disorders.

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.

Interstitial cells of Cajal in health and disease. Part I: normal ICC structure and function with associated motility disorders

Ramon y Cajal (1852-1934) is considered to be one of the founders of the field of neuroscience. In 1911, he described interstitial neurons in the gut, noting that they were primitive accessory components that perhaps modify smooth muscle contraction, themselves subject to regulation from principle neurons. The accuracy of his description of their appearance and activities has led to these cells now being called the interstitial cells of Cajal (ICC). Thuneberg and Faussone-Pellegrini were instrumental in bringing these cells to the attention of gastroenterologists and pathologists in the early 1980s. Subsequently, the development of antibodies to c-kit has allowed routine identification of the ICC in pathology specimens. c-Kit is a transmembrane protein kinase which has as ligand stem cell factor and is involved in cell development in a variety of cell lineages. In the gut musculature, ICC and mast cells are the only cells that have prominent c-kit expression. The ICC are now known to play an important role in gut motility and absent or disordered ICC networks have been identified in a variety of motility disorders.

Interstitial Cells of Cajal and their Role in Veterinary Gastrointestinal Pathologies

This study highlights the importance of interstitial cells of Cajal (ICs) in gastrointestinal disease. Human research is already considering IC pathologies but in veterinary research IC pathologies are rarely studied. Nevertheless, recent studies of ICs show a growing interest in the pathophysiology of gastrointestinal diseases and emphasize the consideration of this cell type in the pathophysiology of veterinary gastrointestinal malfunctions.

Application of HapMap data to the evaluation of 8 candidate genes for pediatric slow transit constipation

BACKGROUND

Slow transit constipation (STC) affects up to 3% of all children and is an increasingly recognized cause of chronic constipation in children. We conducted a pilot study to investigate whether genes encoding neurotransmitters (TAC1, TAC3, VIP, NOS1) and receptors (TACR1, TACR2, TACR3, KIT) could be responsible for STC.

METHODS

One hundred seventeen tag single nucleotide polymorphisms (SNPs), distributed among the candidate genes, were selected from HapMap data and genotyped using Sequenom (San Diego, CA) technology in 35 affected families. Evaluation of association was performed by transmission disequilibrium test and multilocus analysis.

RESULTS

Five SNPs (rs3771863, rs4580655, rs11722288, rs4563545, and rs3782221) in the TACR1, TACR3, KIT, and NOS1 genes were found to be potentially associated with STC, although the significance of these results does not withstand correction for multiple testing.

CONCLUSIONS

Our data indicate that 5 SNPs in the NOS1, TACR1, TACR3, and KIT genes could be involved in STC, especially rs3771863 in intron 1 of TACR1, which showed the highest association.

Colonic neuropathological aspects in patients with intractable constipation due to obstructed defecation

One of the most frequent subtypes of constipation is represented by obstructed defecation, and it has recently been reported that these patients may have colonic motor abnormalities in addition to alterations of the anorectal area. However, it is unknown whether these patients display abnormalities of the enteric nervous system, as reported in other groups of constipated subjects. For this reason, we evaluated the neuropathologic aspects of the enteric nervous system in a homogeneous group of patients with obstructed defecation. Colonic specimens from 11 patients (nine women, age range 39-66 years) undergoing surgery for symptoms refractory to any therapeutic measure, including biofeedback training, were obtained and examined by means of conventional histological methods and immunohistochemistry (NSE, S100, c-Kit, formamide-mAb, Bcl-2, CD34, alfa-actin). Analysis of the specimens showed that the enteric neurons were significantly decreased only in the submucosal plexus of patients (P<0.0001 vs controls), whereas the enteric glial cells of constipated patients were reduced in both the myenteric (P=0.018 vs controls) and the submucosal plexus (P=0.004 vs controls). No difference between patients and controls were found concerning c-Kit and CD34 expression, and the number of apoptotic neurons. These findings support the concept that at least a subgroup of patients with obstructed defecation and severe, intractable symptoms display abnormalities of the enteric nervous system, mostly related to the enteric glial cells. These findings might explain some of the pathophysiological abnormalities, and help to better understand this condition.

Slow transit colon constipation is not related to the number of interstitial cells of Cajal

BACKGROUND AND AIMS

Recent studies have demonstrated decreased numbers of interstitial cells of Cajal in patients suffering from severe chronic constipation as measured by c-Kit (CD117) and CD34 immunohistology. In this study, we wished to determine whether there were abnormalities in the number of neurons of the Auerbach's plexus, their CD117 and CD34 immunoreactivity, or the thickness of colon wall sections in patients with refractory slow transit colonic constipation as compared with control subjects.

PATIENTS AND METHODS

Specimens from 13 patients who had undergone subtotal colectomy for severe chronic constipation refractory to medical treatment were compared with normal controls. Enteric neurons of Auerbach's plexus were counted, and thickness of the circular and longitudinal layer of the muscularis externa as well as total muscularis externa was measured. Quantitative assessment of anti-CD117 and anti-CD34 immunoreactivity was performed using an Automated Cellular Imaging System and expressed as fractional scores.

RESULTS

Except for a decreased circular muscle layer thickness in the constipated patients, no statistically significant differences were observed between the two groups. In particular, there was no relationship between CD117/CD34 fractional staining score and the duration or severity of disease, despite the selection of highly symptomatic individuals requiring colonic resection.

CONCLUSION

Using quantitative immunohistochemistry for CD117/CD34, we could not detect a relationship between fractional CD117/CD34 staining score and chronic constipation as compared to controls.

Enteric neuropathology of congenital intestinal obstruction: A case report

Experimental evidence indicates that chronic mechanical sub-occlusion of the intestine may damage the enteric nervous system (ENS), although data in humans are lacking. We here describe the first case of enteric degenerative neuropathy related to a congenital obstruction of the gut. A 3-year and 9-mo old girl began to complain of vomiting, abdominal distension, constipation with air-fluid levels at plane abdominal radiology. Her subsequent medical history was characterized by 3 operations: the first showed dilated duodeno-jejunal loops in the absence of occlusive lesions; the second (2 years later) was performed to obtain full-thickness biopsies of the dilated intestinal loops and revealed hyperganglionosis at histopathology; the third (9 years after the hyperganglionosis was identified) disclosed a Ladd's band which was removed and the associated gut malrotation was corrected. Repeated intraoperative full-thickness biopsies showed enteric degenerative neuropathy along with reduced interstitial cells of Cajal network in dilated loops above the obstruction and a normal neuromuscular layer below the Ladd's band. One year after the latest surgery the patient tolerated oral feeding and did well, suggesting that congenital (partial) mechanical obstruction of the small bowel in humans can evoke progressive adaptive changes of the ENS which are similar to those found in animal models of intestinal mechanical occlusion. Such ENS changes mimic neuronal abnormalities observed in intestinal pseudo-obstruction.

Enteric neuropathology of the terminal ileum in patients with intractable slow-transit constipation

Slow-transit constipation is usually considered a colonic motor disorder. However, there is some evidence that abnormalities may be present in locations other than the colon. In particular, several studies have reported abnormal motor activity of the small bowel in these patients. We evaluated the neuropathological aspects of the terminal ileum in patients with slow-transit constipation to see whether abnormalities are present that may explain an abnormal motility of the small intestine. Specimens of the terminal ileum were obtained from 16 female patients (age range, 42-76 years) with slow-transit constipation undergoing surgery for intractable symptoms. Fifteen age- and sex-matched controls were used for comparison. Histologic and immunohistochemical evaluation of the myenteric plexus and the smooth muscle of the proximal ileal resection margin was carried out by means of hematoxylin and eosin, trichrome and periodic acid-Schiff stain, neuron-specific enolase, S-100, CD117, CD34, anti-alpha-actin, desmin, and vimentin antibodies. The patient group displayed a significantly reduced number of glial cells, compared with controls, in both the submucosal and the myenteric plexus. Only 1 of the 3 populations of interstitial cells of Cajal (that associated with the deep muscular plexus) was decreased in patients. No differences were found between patients and controls concerning ganglia neurons, fibroblast-like cells, enteric neurons, apoptotic phenomena, and smooth muscle. Patients with slow-transit constipation display neuropathological abnormalities of the terminal ileum to a lesser extent than those we previously found in the colon, which might explain the abnormal motor aspects sometimes found in these patients.

Interstitial cells of Cajal in patients with chagasic megacolon originating from a region of old endemicity

Megacolon is the second most frequent and most important digestive manifestation of Chagas' disease. It is characterized by motor disorders and dilatation of the distal segments of the colon. Several theories have been presented to explain the physiopathology of chagasic megacolon, e.g. the plexus theory.

OBJECTIVE

In the present study the distribution of interstitial cells of Cajal (ICC) was evaluated in colon biopsies from chronic chagasic patients originating from a region of old endemicity for Trypanosoma cruzi and for comparison in subjects with other colon disorders. The chagasic patients had been submitted to colectomy for the investigation of other possible mechanisms underlying the physiopathogenesis of megacolons.

DESIGN STUDY

Twenty-two colon biopsies (15 from chagasic patients and 7 from nonchagasic patients) were examined. ICC were identified by immunohistochemistry by using the anti-CD117 antibody. The number of ICC was determined in longitudinal and circular muscle layers and in the myenteric plexus, and the results were analyzed by the Kruskal-Wallis and Student t-tests.

RESULTS

A reduced number of ICC was observed in all layers and in the myenteric plexus of patients with chagasic megacolon (P<0.05).

CONCLUSIONS

We conclude that the physiopathological manifestations observed in the large bowel of chagasic patients originate from alterations that occur in the ICC, which play an important role in the control of gut motility.