Expression of c-kit messenger ribonucleic acid and c-kit protein in sigmoid colon of patients with slow transit constipation

The Potential Application of Aloe Barbadensis Mill. as Chinese Medicine for Constipation: Mini-Review

Aloe barbadensis Mill. has a long history of medicinal use in the annals of traditional Chinese medicine, wherein it has garnered considerable renown. Its multifaceted therapeutic properties, characterized by its anti-inflammatory and antibacterial attributes, alongside its established efficacy as a laxative agent, have been extensively documented. This review commences with an exploration of the nomenclature, fundamental characteristics, and principal constituents of Aloe barbadensis Mill. responsible for its laxative effects. Subsequently, we delve into an extensive examination of the molecular mechanisms underlying Aloe barbadensis Mill.'s laxative properties, types of constipation treatments, commercially available preparations, considerations pertaining to toxicity, and its clinical applications. This review aims to serve as a comprehensive reference point for healthcare professionals and researchers, fostering an enhanced understanding of the optimal utilization of Aloe barbadensis Mill. in the treatment of constipation.

Research progress in the treatment of slow transit constipation by traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Slow transit constipation (STC) is a common gastrointestinal disorder seriously impacting patients' quality of life. At present, although conventional chemical drugs effectively control STC symptoms in the short term, the long-term effects are poor, and the side effects are significant. In this regard, traditional Chinese medicine (TCM) offers an opportunity for STC treatment. Many pharmacological and clinical studies have confirmed this efficacy of TCM with multiple targets and mechanisms.

AIM OF THE STUDY

This review attempted to summarize the characteristics of TCM (compound prescriptions, single Chinese herbs, and active ingredients) for STC treatment and discussed their efficacy based on analyzing the pathogenesis of STC.

MATERIALS AND METHODS

The information was acquired from different databases, including PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang databases. We then focused on the recent research progress in STC treatment by TCM. Finally, the future challenges and trends are proposed.

RESULTS

TCM has good clinical efficacy in the treatment of STC with multi-mechanisms. Based on the theory of syndrome differentiation, five kinds of dialectical treatment for STC by compound TCM prescriptions were introduced, namely: Nourishing Yin and moistening the intestines; Promoting blood circulation and removing blood stasis; Warming Yang and benefiting Qi; Soothing the liver and regulating Qi; and Benefiting Qi and strengthening the spleen. In addition, six single Chinese herbs and eight active ingredients also show good efficacy in STC treatment.

CONCLUSIONS

TCM, especially compound prescriptions, has bright prospects in treating STC attributed to its various holistic effects.

Prokinetic effects of diatrizoate meglumine (Gastrografin®) in a zebrafish for opioid-induced constipation model

Constipation is a common disease that reduces life quality. Drugs of various mechanisms are being developed to resolve this affliction. Intestinal motility can be easily monitored in zebrafish, and so we selected this organism to develop a constipation model to measure drug-induced prokinetic effects. In this study, intestinal motility was monitored in zebrafish by tracking intestinal transit using fluorescence, after which an opioid-induced constipation model was established using loperamide. We then evaluated the prokinetic effect of diatrizoate meglumine (Gastrografin®), which has been empirically used to treat post-operative ileus or adhesive small bowel obstructions. Diatrizoate meglumine was effective in promoting bowel movements in an opioid-induced zebrafish constipation model and its prokinetic effect was associated with an increased expression of interstitial cells of Cajal (ICC) markers. Therefore, the loperamide-induced zebrafish constipation model developed herein is a promising tool to evaluate novel constipation therapies.

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.

miR-222 regulates cell growth, apoptosis, and autophagy of interstitial cells of Cajal isolated from slow transit constipation rats by targeting c-kit

BACKGROUND

Excessive autophagy and apoptosis of the interstitial cells of Cajal (ICC) have been identified in gastrointestinal (GI) motility disorders including slow transit constipation (STC). MicroRNA 222 (miR-222) has been shown to affect GI motility. This study aimed to explore whether miR-222 influences apoptosis and excessive autophagy of isolated ICC.

METHODS

miR-222, c-kit, and stem cell factor (SCF) were evaluated in colon tissues in STC rats compared with normal control by qRT-PCR and western blot analysis. The condition of autophagy of colon tissue was observed by transmission electron microscope. ICC were isolated from the colon of STC rats. Cell Counting Kit-8 (CCK-8) assay and wound healing assay were carried out to examine the cell viability and migration rate. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and Annexin V-Flourescein Isothiocyanate/Propidine Iodide (FITC/PI) apoptosis detection kit. Western blot analysis was performed to detect the c-kit and SCF expression; apoptosis-related proteins Bcl-2, Bax, caspase-3, and pro-caspase-3; and autophagy-related proteins LC3B and Beclin-1. The connection between miR-222 and c-kit was detected by bioinformatics and luciferase activity analysis.

RESULTS

miR-222 expression was significantly higher, whereas c-kit and SCF expressions were markedly lower in STC rats' colon tissue compared with normal control. Meanwhile, STC rats exhibited excessive autophagy in colon tissue than normal control. Inhibition of miR-222 expression promoted cell proliferation as well as migration and inhibited autophagy, whereas upregulation of miR-222 had the opposite effect. In addition, miR-222 upregulation induced apoptosis and excessive autophagy compared with normal controls (NC). Western blot analysis showed that miR-222 overexpression caused decreased c-kit and SCF protein levels compared with NC. Bioinformatics and luciferase activity analysis revealed that miR-222 could be a predictive regulator of c-kit.

CONCLUSION

miR-222 induces apoptosis and excessive autophagy of ICC and may serve as potential biomarker for ICC loss in STC.

Curative Effect and Mechanism of Guiren Runchang Granules on Morphine-Induced Slow Transit Constipation in Mice

Recent studies have identified the curative effects of traditional Chinese medicine for constipation. The mechanism of action of Guiren Runchang granules (GRGs) in the treatment of slow transit constipation (STC) was evaluated in this study. Here, we assessed the efficacy of GRG by comparing the differences in fecal characteristics, stool weight, and intestinal transit rate (ITR) among 6 groups (n = 12/group), which were administered three concentrations of GRG, mosapride, and saline. The influence of GRG on the SCF/c-kit pathway, AQP4, and serum motilin of mice was assessed through ELISA, western blot, and immunohistochemical analysis. The dry weight of mouse feces at 24 hr and ITR in the MD (medium-dose GRG; 9.44 g/kg/d) and HD (high-dose GRG; 18.88 g/kg/d) groups was higher than that in the MC (model control) group. The serum motilin of morphine-induced mice level was lower in the MC group than in the NC (normal control) group, and this condition was improved in the HD group. The HD group expressed significantly higher levels of SCF and c-kit protein but lower levels of AQP4 and simultaneously presented more SCF-positive and c-kit-positive cells. However, no differences in the serum SCF level were found among the six groups. Certain concentrations of GRG are effective in STC mice, the potential mechanism of which may be associated with repairing the SCF/c-kit pathway and reducing the expression of AQP4 in the colon. GRG improved the serum motilin level but had no influence on the serum SCF level.

Astragaloside IV alleviates mouse slow transit constipation by modulating gut microbiota profile and promoting butyric acid generation

Gut microbiota and short‐chain fatty acids (SCFAs) are associated with the development of various human diseases. In this study, we examined the role of astragaloside IV in modulating mouse gut microbiota structure and the generation of SCFAs, as well as in slow transit constipation (STC). An STC model was established by treating mice with loperamide, in which the therapeutic effects of astragaloside IV were evaluated. The microbiota community structure and SCFA content were analysed by 16S rRNA gene sequencing and gas chromatography‐mass spectrometry, respectively. The influence of butyrate on STC was assessed using a mouse model and Cajal cells (ICC). Astragaloside IV promoted defecation, improved intestinal mobility, suppressed ICC loss and alleviated colonic lesions in STC mice. Alterations in gut microbiota community structure in STC mice, such as decreased Lactobacillus reuteri diversity, were improved following astragaloside IV treatment. Moreover, astragaloside IV up‐regulated butyric acid and valeric acid, but decreased isovaleric acid, in STC mouse stools. Butyrate promoted defecation, improved intestinal mobility, and enhanced ICC proliferation by regulating the AKT–NF‐κB signalling pathway. Astragaloside IV promoted intestinal transit in STC mice and inhibited ICC loss by regulating the gut microbiota community structure and generating butyric acid.

Manipulation of intestinal dysbiosis by a bacterial mixture ameliorates loperamide-induced constipation in rats

Constipation has a significant influence on quality of life. Patients with constipation have slow waves in their gastrointestinal smooth muscles and less faecal water contents, which are closely associated with down-regulation of the interstitial cells of Cajal (ICC) in the gastrointestinal muscles and the aquaporin protein AQP3 expressed in colon epithelial cells. Recent studies supported that patients with constipation have altered intestinal microbial structures compared with healthy controls. Intestinal dysbiosis might be one possible pathophysiological mechanism causing constipation. Bacterial strains, such as Lactobacillus spp., have shown many beneficial effects on the amelioration of constipation. However, few studies reported the structural changes of intestinal microbiota post-intervention of probiotics. In this study, a bacterial mixture was administrated to rats with loperamide-induced constipation. Effects of the bacterial mixture on small intestine transit (SIT), faecal water content, and the intestinal microbiome in rats were evaluated. Meanwhile, we investigated several factors involved in signalling pathways that regulate function of ICC and expression of AQP3 to discuss the possible underlying molecular mechanisms. Intervention of the bacterial mixture improved SIT and faecal water content in constipated rats. The up-regulation of C-kit/SP signalling pathways in ICC and AQP3 significantly contributed to improvements. These changes were closely associated with the manipulation of intestinal dysbiosis in constipated rats. Furthermore, our results revealed the important role of intestinal microbiota in affecting gut motility through regulation of serotonin biosynthesis. This monoamine neurotransmitter, secreted from enterochromaffin cells, up-regulated both substance P/neurokinin 1 receptors pathway of ICC and the expression of AQP3 in intestinal epithelial cells. Our study suggested that the disrupted microbiome in patients could be a potential therapeutic target for the improvement of constipation.

Searching for a definition for pharmacologically refractory constipation: A systematic review

BACKGROUND AND AIM

Surgery and other non-pharmacological treatments such as sacral nerve stimulation are used for the treatment of difficult-to-treat chronic constipation. Novel pharmacological therapeutic agents are also being introduced. To evaluate the efficacy of these treatments, it is imperative to have a consistent definition of pharmacologically refractory constipation. A systematic review of studies on refractory, difficult-to-treat or surgically treated constipation was carried out to determine the criteria that various authors used to define this group of patients.

METHODS

A systematic review was performed for literature published from June 2005 to June 2015 using PubMed, Cochrane, and Scopus databases, as well as manual searches. Studies on patients with refractory or intractable constipation were extracted. Criteria used for defining refractory constipation, as well as pharmacological agents tried including dosage, frequency, and duration, were reviewed.

RESULTS

Sixty-one studies were included in this review. Forty-eight involved surgical treatment of constipation, while 13 examined non-surgical therapies for refractory constipation. There is no generally accepted definition of refractory constipation. Authors consider constipation to be refractory when response to management is suboptimal, but there is no consensus on the choice of drug, order of usage, and dosage or treatment duration. Prior medical therapy was not mentioned at all in five studies.

CONCLUSIONS

There is need for a detailed definition of pharmacologically refractory constipation before submitting patients to invasive treatments and to evaluate new pharmacological agents.

Comparison of Changes in the Interstitial Cells of Cajal and Neuronal Nitric Oxide Synthase-positive Neuronal Cells With Aging Between the Ascending and Descending Colon of F344 Rats

Background/Aims

Neuronal degeneration and changes in interstitial cells of Cajal (ICCs) are important mechanisms of age-related constipation. This study aims to compare the distribution of ICCs and neuronal nitric oxide synthase (nNOS) with regard to age-related changes between the ascending colon (AC) and descending colon (DC) in 6-, 31-, and 74-week old and 2-year old male Fischer-344 rats.

Methods

The amount of fecal pellet and the bead expulsion times were measured. Fat proportion in the muscle layer of the colon was analyzed by hematoxylin and eosin staining. Proto-oncogene receptor tyrosine kinase (KIT) and neuronal nitric oxide synthase (nNOS) expression were analyzed with Western blotting and immunohistochemistry. Isovolumetric contractile measurements and electrical field stimulation were used to assess smooth muscle contractility.

Results

Colon transit and bead expulsion slowed with senescence. Fat in the muscle layer accumulated with age in the AC, but not in the DC. The proportion of KIT-immunoreactive ICCs in the submucosal and myenteric plexus was higher in the DC than in the AC, and it declined with age, especially in the AC. In contrast, the proportion of NOS-immunoreactive neurons in the myenteric plexus was higher in the AC than in the DC, and both decreased in older rats. Nitric oxide levels declined with age in the DC. Muscle strip experiments showed that the inhibitory response mediated by nitric oxide in the circular direction of the DC was reduced in 2-year old rats.

Conclusion

The AC and DC differ in their distribution of ICCs and nNOS, and age-related loss of nitrergic neurons more severely affects the DC than the AC.

Nicotinamide adenine dinucleotide replenishment rescues colon degeneration in aged mice

Susceptibility of gastrointestinal dysmotility increases with age-associated colonic degeneration. A paucity of remedies reversing colonic degeneration per se hinders the fundamental relief of symptoms. Here we discovered the correlation between colon degeneration and altered nicotinamide adenine dinucleotide (NAD) level in aged mice. Compared to 3-month-old young controls, 2-year-old mice showed a spectrum of degenerative colonic phenotypes and exhibited a significant elongated transit time and slowed stool frequency in the context of Lomotil-induced slow-transit constipation. Despite upregulated colonic tryptophan hydroxylases expression, serotonin release and expression of colon-predominant type IV serotonin receptor, reduced viability of interstitial cells of Cajal while enhanced aquaporins (Aqp1, 3 and 11) led to a less colonic motility and increased luminal dehydration in aged mice. Notably, this colonic degeneration was accompanied with reduced key NAD⁺-generating enzyme expression and lowered NAD⁺/NADH ratio in aged colon. Three-month continuous administration of beta nicotinamide mononucleotide, a NAD⁺ precursor, elevated colonic NAD⁺ level and improved defecation in aged mice. In contrast, pharmacological inhibition of nicotinamide phosphoribosyltransferase, the rate-limiting enzyme for NAD⁺ biosynthesis, induced a reduction in colonic NAD content and impaired gastrointestinal function in young mice. Taken together, these findings suggest the beneficial effect of NAD⁺ in maintaining colonic homoeostasis and reactivating NAD⁺ biosynthesis may represent a promising strategy to counteract age-related gastrointestinal degeneration.

Evaluation of interstitial cells of Cajal in patients with severe colonic inertia requiring surgery: a clinical-pathological study

AIM

Subtotal colectomy is the treatment of last resort in patients with severe colonic inertia (SCI) refractory to laxatives. Some studies have reported hypoplasia of the interstitial cells of Cajal (ICC) using a semi-quantitative analysis. The aims of this study were first to investigate if semi-quantitative analysis or morphometry is better at the quantification of colonic ICC and second to determine whether there is a relationship between the number of ICC and the severity of constipation.

METHOD

Clinical and pathological data from patients with subtotal colectomy for SCI were collected. Quantification of ICC using CD117 immunohistochemistry and morphometric methods was performed at three different colonic sites in patients and controls.

RESULTS

Twenty patients had a colectomy for SCI. All were considered to have failed maximal medical treatment and 45% were hospitalized at least once for colonic obstruction due to faecaloma. Using a semi-quantitative methodology, 30% of patients displayed ICC hypoplasia (< 7 per high power field) and all controls had normal ICC. Using morphometry, the percentage of colonic ICC was significantly less in patients compared with controls with no significant differences between the ascending, transverse and descending colonic segments. Overall 60% of patients had ICC hypoplasia (< 1% vs 20% of controls, P = 0.009). The severity of constipation was not related to the quantity of ICC.

CONCLUSION

In patients with SCI, morphometric analysis is more sensitive than semi-quantitative analysis in the detection of ICC hypoplasia. The severity of constipation was not related to the quantity of ICC.

Total Glucosides of Paeony Promote Intestinal Motility in Slow Transit Constipation Rats through Amelioration of Interstitial Cells of Cajal

Objectives

Using an atropine-diphenoxylate-induced slow transit constipation (STC) model, this study explored the effects of the total glucosides of paeony (TGP) in the treatment of STC and the possible mechanisms.

Study Design

A prospective experimental animal study.

Methods

The constipation model was set up in rats with an oral gavage of atropine-diphenoxylate and then treated with the TGP. The volume and moisture content of the faeces were observed and the intestinal kinetic power was evaluated. Meanwhile, the colorimetric method and enzyme linked immunosorbent assay (ELISA) were employed to determine the changes of nitric oxide (NO), nitric oxide synthase (NOS), vasoative intestinal peptide (VIP) and the P substance (SP) in the serum, respectively. The protein expressions of c-kit and stem cell factor (SCF) were assessed by immunohistochemical analysis and western blot, respectively, and the mRNA level of c-kit was measured by a reverse transcription polymerase chain reaction (RT-PCR).

Results

The TGP attenuated STC responses in terms of an increase in the fecal volume and moisture content, an enhancement of intestinal transit rate and the reduction of NO, NOS and VIP in the serum. In addition, the c-kit, a labeling of interstitial cells of Cajal (ICC) increased at both protein and mRNA levels. SCF, which serves as a ligand of c-kit also increased at protein level.

Conclusion

The analysis of our data indicated that the TGP could obviously attenuate STC through improving the function of ICC and blocking the inhibitory neurotransmitters such as NO, NOS and VIP.

Fat deposition in the tunica muscularis and decrease of interstitial cells of Cajal and nNOS-positive neuronal cells in the aged rat colon

Little is known about the time course of aging on interstitial cells of Cajal (ICC) of colon. The aim of this study was to investigate the change of morphology, ICC, and neuronal nitric oxide synthase (nNOS)-immunoreactive cells in the aged rat. The proximal colon of 344 Fischer rats at four different ages (6, 31, 74 wk, and 2 yr) were studied. The immunoreactivity of c-Kit, nNOS, anti-protein gene product 9.5, and synaptophysin were counted after immunohistochemistry. The c-kit, stem cell factor (ligand of Kit), and nNOS mRNA were measured by real-time PCR. c-Kit and nNOS protein were assessed by Western blot. Isovolumetric contractile force measurement and electrical field stimulation (EFS) were conducted. The area of intramuscular fat deposition significantly increased with age after 31 wk. c-Kit-immunoreactive ICC and nNOS-immunoreactive neurons and nerve fibers significantly declined with age. mRNA and protein expression of c-kit and nNOS decreased with aging. The functional study showed that the spontaneous contractility was decreased in aged rat, whereas EFS responses in the presence of atropine and L-NG-Nitroarginine methyl ester were increased in aged rat. In conclusion, the decrease of proportion of proper smooth muscle, the density of ICC and nNOS-immunoreactive neuronal fibers, and the number of nNOS-immunoreactive neurons during the aging process may explain the aging-associated colonic dysmotility.

The KIT gene is associated with the english spotting coat color locus and congenital megacolon in Checkered Giant rabbits (Oryctolagus cuniculus)

The English spotting coat color locus in rabbits, also known as Dominant white spotting locus, is determined by an incompletely dominant allele (En). Rabbits homozygous for the recessive wild-type allele (en/en) are self-colored, heterozygous En/en rabbits are normally spotted, and homozygous En/En animals are almost completely white. Compared to vital en/en and En/en rabbits, En/En animals are subvital because of a dilated (“mega”) cecum and ascending colon. In this study, we investigated the role of the KIT gene as a candidate for the English spotting locus in Checkered Giant rabbits and characterized the abnormalities affecting enteric neurons and c-kit positive interstitial cells of Cajal (ICC) in the megacolon of En/En rabbits. Twenty-one litters were obtained by crossing three Checkered Giant bucks (En/en) with nine Checkered Giant (En/en) and two en/en does, producing a total of 138 F1 and backcrossed rabbits. Resequencing all coding exons and portions of non-coding regions of the KIT gene in 28 rabbits of different breeds identified 98 polymorphisms. A single nucleotide polymorphism genotyped in all F1 families showed complete cosegregation with the English spotting coat color phenotype (θ = 0.00 LOD  = 75.56). KIT gene expression in cecum and colon specimens of En/En (pathological) rabbits was 5–10% of that of en/en (control) rabbits. En/En rabbits showed reduced and altered c-kit immunolabelled ICC compared to en/en controls. Morphometric data on whole mounts of the ascending colon showed a significant decrease of HuC/D (P<0.05) and substance P (P<0.01) immunoreactive neurons in En/En vs. en/en. Electron microscopy analysis showed neuronal and ICC abnormalities in En/En tissues. The En/En rabbit model shows neuro-ICC changes reminiscent of the human non-aganglionic megacolon. This rabbit model may provide a better understanding of the molecular abnormalities underlying conditions associated with non-aganglionic megacolon.

Cellular and molecular basis of chronic constipation: Taking the functional/idiopathic label out

In recent years, the improvement of technology and the increase in knowledge have shifted several strongly held paradigms. This is particularly true in gastroenterology, and specifically in the field of the so-called “functional” or “idiopathic” disease, where conditions thought for decades to be based mainly on alterations of visceral perception or aberrant psychosomatic mechanisms have, in fact, be reconducted to an organic basis (or, at the very least, have shown one or more demonstrable abnormalities). This is particularly true, for instance, for irritable bowel syndrome, the prototype entity of “functional” gastrointestinal disorders, where low-grade inflammation of both mucosa and myenteric plexus has been repeatedly demonstrated. Thus, researchers have also investigated other functional/idiopathic gastrointestinal disorders, and found that some organic ground is present, such as abnormal neurotransmission and myenteric plexitis in esophageal achalasia and mucosal immune activation and mild eosinophilia in functional dyspepsia. Here we show evidence, based on our own and other authors’ work, that chronic constipation has several abnormalities reconductable to alterations in the enteric nervous system, abnormalities mainly characterized by a constant decrease of enteric glial cells and interstitial cells of Cajal (and, sometimes, of enteric neurons). Thus, we feel that (at least some forms of) chronic constipation should no more be considered as a functional/idiopathic gastrointestinal disorder, but instead as a true enteric neuropathic abnormality.

Involvement of interstitial cells of Cajal in experimental severe acute pancreatitis in rats

AIM: To observe the changes in interstitial cells of Cajal (ICC) in rats with experimental severe acute pancreatitis (SAP).

METHODS: A total of twenty-four SD rats were randomly divided into two groups (n = 12), namely the sham (S) group and the SAP group; the SAP rat model was established by retrograde injection of 5% sodium taurocholate (1.0 mL/kg) into the pancreatic duct. Twenty-four hours later intestinal motility was assessed by testing small intestinal propulsion rate, and then the rats were sacrificed. The pancreas and jejunum were resected and underwent routine pathologic examination. Immunohistochemical staining was used to detect c-kit-positive cells in the jejunum. Expression of c-kit mRNA was detected by real-time polymerase chain reaction, and the expression of c-kit protein was evaluated by Western blotting. Ultrastructure of ICC was evaluated by transmission electron microscopy.

RESULTS: There was bleeding, necrosis and a large amount of inflammatory cell infiltration in pancreatic tissue in the SAP group, while in jejunal tissue we observed a markedly denuded mucosal layer, loss of villous tissue and a slightly dilated muscular layer. The small intestinal propulsion rate was 68.66% ± 2.66% in the S group and 41.55% ± 3.85% in the SAP group. Compared with the S group, the rate of the SAP group decreased sharply. The density of c-kit-positive cells in the SAP group was significantly lower than in the S group; the respective mean densities were 88.47 ± 10.49 in the S group and 56.11 ± 7.09 in the SAP group. The levels of c-kit protein and mRNA were 0.36 ± 0.04 and 1.29 ± 0.91 in the SAP group, respectively, which were significantly lower than those in the S group (0.53 ± 0.06, 0.64 ± 0.33, respectively). In the SAP group, ICC profiles showed the same change tendency, such as vacuolation of mitochondria, irregular vacuoles and loosened desmosome-like junctions.

CONCLUSION: Decreased c-kit-positive cells and ultrastructural changes in ICC resulting from blockade of the c-kit signaling pathway are involved in the intestinal dysmotility associated with SAP.

Progress in understanding mechanisms underlying the regulatory effect of acupuncture on functional constipation

Functional constipation is a common and frequently-occurring disease whose etiology and pathogenesis are still not very clear. Experimental studies using animal models of cathartic colon have shown abnormalities in ultrastructural plexus of enteric nervous system (ENS), expression of multiple receptors, and interstitial cells of Cajal (ICC). Currently, there has been no consensus reached yet with regard to the mechanisms underlying the regulatory effect of acupuncture therapy on functional constipation, and the interaction among different regulatory mechanisms is not examined in depth. Future research should address this issue to better understand how acupuncture exerts therapeutic effects against functional constipation.

Gastrointestinal neuromuscular pathology in chronic constipation

Some patients with chronic constipation may undergo colectomy yielding tissue appropriate to diagnosis of underlying neuromuscular pathology. The analysis of such tissue has, over the past 40 years, fueled research that has explored the presence of neuropathy, myopathy and more recently changes in interstitial cells of Cajal (ICC). In this chapter, the data from these studies have been critically reviewed in the context of the significant methodological and interpretative issues that beset the field of gastrointestinal neuromuscular pathology. On this basis, reductions in ICC appear to a consistent finding but one whose role as a primary cause of slow-transit constipation requires further evaluation. Findings indicative of significant neuropathy or myopathy are variable and in many studies subject to considerable methodological bias. Methods with practical diagnostic utility in the individual patient have rarely been employed and require further validation in respect of normative data.

Adenovirus-mediated stem cell leukemia gene transfer induces rescue of interstitial cells of Cajal in ICC-loss mice

OBJECTIVE

Interaction of c-Kit and its ligand stem cell factor (SCF) is necessary for appropriate development and survival of interstitial cells of Cajal (ICC) in the intestine. Blockade of c-Kit will cause ICC loss in vivo. Stem cell leukemia (SCL) gene acts as a positive regulator of upstream transcription of c-Kit expression. This study aimed to explore whether the restoration of c-Kit expression promoted by SCL gene transfer could rescue ICC in vivo.

MATERIALS AND METHODS

A modified ICC-loss mouse model was created by continual administration of anti-c-Kit antibody (ACK2) to obtain a steady status of ICC loss, and a recombinant adenovirus vector containing SCL gene (Ad-SCL) was designed to rescue ICC in these mice. Western blot analysis and immunofluorescence labeling assays were performed to analyze the SCL and c-Kit expression in vitro and in vivo. The distribution and configuration of ICC were observed with immunohistochemistry and electromicroscope.

RESULTS

Western blot analysis and immunofluorescence labeling assays showed that SCL gene was successfully delivered to cultured HeLa and ICC cells in vitro. Moreover, significantly increased c-Kit expression could be detected in the colon of Ad-SCL-infected ICC-loss mice. Furthermore, rescue of the ICC network and ICC with typical ultrastructural features could be detected in Ad-SCL-infected ICC-loss mice at day 37.

CONCLUSIONS

Ad-SCL was able to enhance c-Kit expression, reactivate the c-Kit/SCF pathway, and rescue ICC in ICC-loss mice. Since loss and defects of ICC are associated with many human gut motility disorders, Ad-SCL may be of potential use in gene therapy of these patients.

Diagnostic challenges of motility disorders: optimal detection of CD117+ interstitial cells of Cajal

AIMS

Several gastrointestinal motility diseases are associated with altered numbers of interstitial cells of Cajal (ICC), and testing for alterations in numbers of ICC has been proposed as one way to improve routine diagnosis in motility diseases. However, the protocols currently used to visualize ICC in formalin-fixed paraffin-embedded (FFPE) tissue using antibodies to CD117 have not been optimized for studying motility disorders. The aims of this study were therefore to determine the optimal protocol using FFPE tissue, determine normal values for ICC in non-neoplastic human colon, and compare results with those obtained using immunofluorescence (IF).

METHODS AND RESULTS

Non-neoplastic tissue was collected from patients undergoing resection for colonic cancer and fixed for both light (FFPE) and IF testing. Sections were processed for standard immunohistochemistry using different primary antibodies in conjunction with variations in antigen retrieval [ethylenediamine tetraacetricacid (EDTA), citrate], antibody dilution, blocking and detection (Mach2, Mach3, Envision+). Best results were obtained with EDTA retrieval, the DAKO CD117 antibody and Mach3 detection.

CONCLUSIONS

The optimized protocol presented improved CD117 detection in FFPE tissues and showed good concordance with overall localization of CD117-immunoreactive ICC as detected by IF. As such, this protocol may be more useful than current diagnostic procedures in motility disorders.

The nervous system and gastrointestinal function

The enteric nervous system is an integrative brain with collection of neurons in the gastrointestinal tract which is capable of functioning independently of the central nervous system (CNS). The enteric nervous system modulates motility, secretions, microcirculation, immune and inflammatory responses of the gastrointestinal tract. Dysphagia, feeding intolerance, gastroesophageal reflux, abdominal pain, and constipation are few of the medical problems frequently encountered in children with developmental disabilities. Alteration in bowel motility have been described in most of these disorders and can results from a primary defect in the enteric neurons or central modulation. The development and physiology of the enteric nervous system is discussed along with the basic mechanisms involved in controlling various functions of the gastrointestinal tract. The intestinal motility, neurogastric reflexes, and brain perception of visceral hyperalgesia are also discussed. This will help better understand the pathophysiology of these disorders in children with developmental disabilities.

Interstitial cells of Cajal in the gut - A gastroenterologist’s point of view

Alterations of normal function of interstitial cells of Cajal (ICC) are reported in many intestinal disorders. Diagnosis of their involvement is rare (infrequent), but necessary to propose a specific treatment. This article reviews the place of ICC in the pathogenesis of achalasia, gastroesophageal reflux disease, infantile hypertrophic pyloric stenosis, chronic intestinal pseudo-obstruction and slow transit constipation. Moreover we discuss the role of the Cajal cells in the development of stromal tumors of the gastrointestinal tract.

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.

Electrogastrography: Poor correlation with antro-duodenal manometry and doubtful clinical usefulness in adults

AIM: To investigate if there is a correlation between electrical activity measured by electrogastrography (EGG) and contractile activity of the stomach as measured by antroduodenal manometry (ADM). We also studied whether the underlying motility disorder could be predicted from EGG parameters.

METHODS: We compared 21 parameters measured from EGG with 8 parameters measured from ADM. The ability of EGG to identify the underlying diagnosis was tested by comparing EGG parameters for each diagnosis group against other patients. The study comprised recordings from 148 patients and 125 females. Their median age was 45 (range 17-76) years.

RESULTS: We found few and weak correlations between EGG and ADM. Specifically the correlation between parameters reflecting the response to meal was poor (r = -0.07, P = 0.39). The discriminatory power of EGG for underlying motility disorder was also low. Patients with slow transit constipation (STC) showed a lower postprandial power in normogastric (3.7 ± 0.5 vs 4.0 ± 0.5) and tachygastric (3.5 ± 0.4 vs 3.7 ± 0.4) regions, a lower percentage of time with normogastria [87.2 (56.5-100)% vs 95.7 (0-100)%], and a higher percentage of time with tachygastria [9.3 (0-33)% vs 3.5 (0-100)%] and bradygastria [1.8 (0-20)% vs 0 (0-17.1)%]. Patients with irritable bowel syndrome had a higher percentage of time with normogastria [96.5 (62.5-100)% vs 93.3 (0-100)%] and a less unstable dominant frequency as measured by the instability coefficient [15 (3-77) vs 24 (2-72)].

CONCLUSION: EGG and ADM seem to measure different aspects of gastric motor activity but cannot show a spatial correlation. The diagnostic value of EGG is poor, but EGG may have some value for the identification of patients with STC.

Gastrointestinal motility disorders in adolescent patients: transitioning to adult care

A wide spectrum of gastrointestinal motility disorders present in childhood. Some are unique to children, especially congenital disorders including certain pseudo-obstruction disorders or those associated with anatomic developmental defects, whereas others are common adult disorders, such as achalasia, that rarely manifest in children. This article reviews the pediatric presentations and sequelae of childhood gastrointestinal motility disorders and then discusses long-term management issues for these children as they progress into adulthood. The goal is to optimize medical care and ensure the adequate nutritional status essential for neurocognitive and psychosocial development of the child. Multidisciplinary care from specialists, including gastroenterologists, psychologists, and pain specialists, is often required to optimize the lives of these patients.

Myoelectric activity and motility of the Roux limb after cut or uncut Roux-en-Y gastrojejunostomy

AIM: To explore the mechanisms of uncut Roux-en-Y gastrojejunostomy, which is used to decrease the occurrence of Roux stasis syndrome.

METHODS: The changes of myoelectric activity, mechanic motility and interstitial cells of Cajal (ICC) of the Roux limb after cut or uncut Roux-en-Y gastrojejunostomy were observed.

RESULTS: When compared with the cut group, the amplitude (1.15 ± 0.15 mV vs 0.48 ± 0.06 mV, P < 0.05) and frequency (14.4 ± 1.9 cpm vs 9.5 ± 1.1 cpm, P < 0.01) of slow waves and the incidence (98.2% ± 10.4% vs 56.6% ± 6.4%, P < 0.05) and amplitude (0.58 ± 0.08 mV vs 0.23 ± 0.06 mV, P < 0.01) of spike potential of the Roux limb in the uncut group were significantly higher. The migrating myoelectric complexes (MMC) phase III duration in the uncut group was significantly prolonged (6.5 ± 1.1 min vs 4.4 ± 0.8 min, P < 0.05), while the MMC cycle obviously shortened (42.5 ± 6.8 vs 55.3 ± 8.2 min, P < 0.05). Both gastric emptying rate (65.5% ± 7.9% vs 49.3% ± 6.8%, P < 0.01) and intestinal impelling ratio (53.4% ± 7.4% vs 32.2% ± 5.4%, P < 0.01) in the uncut group were significantly increased. The contractile force index of the isolated jejunal segment in the uncut group was significantly higher (36.8 ± 5.1 vs 15.3 ± 2.2, P < 0.01), and the expression of c-kit mRNA was significantly increased in the uncut group (0.82 ± 0.11 vs 0.35 ± 0.06, P < 0.01).

CONCLUSION: Uncut Roux-en-Y gastrojejunostomy may lessen the effects of operation on myoelectric activity such as slow waves, spike potential, and MMC, decrease the impairment of gastrointestinal motility, and remarkably increase the expression of c-kit mRNA.

Tobacco smoking: a factor of early onset of colorectal cancer

PURPOSE

Tobacco smoking is associated with a higher risk of developing colorectal cancer. This study was designed to assess the role of smoking in early onset of colorectal pathology.

METHODS

This was a prospective cross-sectional study of 997 patients with colorectal cancer. Age of colorectal cancer diagnosis was studied in two groups of patients, i.e., smokers (>10 pack-years) and nonsmokers. Confounding factors, such as alcohol drinking, obesity, and gender, also were studied using a correlation analysis and multivariate logistic regression analysis.

RESULTS

Of the 997 patients, 852 had sufficient data for analysis and were included. Baseline analysis showed that excluded patients had similar demographic characteristics. Smokers (n=108) reported symptoms related to colorectal cancer at an earlier mean age (64.1 (standard deviation, 11.7) years) than nonsmokers (69.6 (standard deviation, 12.6) years; mean difference, 5.5 (standard deviation, 1.2 years); P<0.001). Impact of smoking according to the bowel segment involved was significant for slow-transit segments (transverse and sigmoid colon and rectum). Multivariate analysis revealed that tobacco smoking was the only independent risk factor of early onset of colorectal cancers.

CONCLUSIONS

Tobacco smoking could be a factor of early onset of colorectal cancers especially for slow-transit bowel segments. If these findings are confirmed in larger studies, screening for colorectal cancer should not involve a simple sigmoidoscopy but also an exploration of transverse colon in smokers.

Slow transit constipation: A functional disorder becomes an enteric neuropathy

Slow transit constipation has been traditionally considered and classified as a functional disorder. However, clinical and manometric evidence has been accumulating that suggests how most of the motility alterations in STC might be considered of neuropathic type.In addition, further investigations showed that subtle alterations of the enteric nervous system, not evident to conventional histological examination, may be present in these patients. In the present article we will discuss these evidences, and will try to put them in relation with the abnormal motor function of the large bowel documented in this pathological condition.

The role of glial cells and apoptosis of enteric neurones in the neuropathology of intractable slow transit constipation

BACKGROUND

Idiopathic slow transit constipation is one of the most severe and often intractable forms of constipation. As motor abnormalities are thought to play an important pathogenetic role, studies have been performed on the colonic neuroenteric system, which rules the motor aspects of the viscus.

AIMS

We hypothesised that important neuropathological abnormalities of the large bowel are present, that these are not confined to the interstitial cells of Cajal and ganglion cells, and that the previously described reduction of enteric neurones, if confirmed, might be related to an increase in programmed cell death (apoptosis).

PATIENTS AND METHODS

Surgical specimens from 26 severely constipated patients were assessed by conventional and immunohistochemical methods. Specific staining for enteric neurones, glial cells, interstitial cells of Cajal, and fibroblast-like cells associated with the latter were used. In addition, gangliar cell apoptosis was evaluated by means of indirect and direct techniques. Data from patients were compared with those obtained in 10 controls.

RESULTS

Severely constipated patients displayed a significant decrease in enteric gangliar cells, glial cells, and interstitial cells of Cajal. Fibroblast-like cells associated with the latter did not differ significantly between patients and controls. Patients had significantly more apoptotic enteric neurones than controls.

CONCLUSION

Severely constipated patients have important neuroenteric abnormalities, not confined to gangliar cells and interstitial cells of Cajal. The reduction of enteric neurones may in part be due to increased apoptotic phenomena.

Novel type of interstitial cell (Cajal-like) in human fallopian tube

We describe here--presumably for the first time--a Cajal-like type of tubal interstitial cells (t-ICC), resembling the archetypal enteric ICC. t-ICC were demonstrated in situ and in vitro on fresh preparations (tissue cryosections and primary cell cultures) using methylene-blue, crystal-violet, Janus-Green B or MitoTracker-Green FM Probe vital stainings. Also, t-ICC were identified in fixed specimens by light microscopy (methylene-blue, Giemsa, trichrome stainings, Gomori silver-impregnation) or transmission electron microscopy (TEM). The positive diagnosis of t-ICC was strengthened by immunohistochemistry (IHC; CD117/c-kit+ and other 14 antigens) and immunofluorescence (IF; CD117/c-kit+ and other 7 antigens). The spatial density of t-ICC (ampullar-segment cryosections) was 100-150 cells/mm2. Non-conventional light microscopy (NCLM) of Epon semithin-sections revealed a network-like distribution of t-ICC in lamina propria and smooth muscle meshwork. t-ICC appeared located beneath of epithelium, in a 10-15 microm thick 'belt', where 18+/-2% of cells were t-ICC. In the whole lamina propria, t-ICC were about 9%, and in muscularis approximately 7%. In toto, t-ICC represent ~8% of subepithelial cells, as counted by NCLM. In vitro, t-ICC were 9.9+/-0.9% of total cell population. TEM showed that the diagnostic 'gold standard' (Huizinga et al., 1997) is fulfilled by 'our' t-ICC. However, we suggest a 'platinum standard', adding a new defining criterion- characteristic cytoplasmic processes (number: 1-5; length: tens of microm; thickness: < or =0.5 microm; aspect: moniliform; branching: dichotomous; organization: network, labyrinthic-system). Quantitatively, the ultrastructural architecture of t-ICC is: nucleus, 23.6+/-3.2% of cell volume, with heterochromatin 49.1+/-3.8%; mitochondria, 4.8+/-1.7%; rough and smooth endoplasmic-reticulum (1.1+/-0.6%, 1.0+/-0.2%, respectively); caveolae, 3.4+/-0.5%. We found more caveolae on the surface of cell processes versus cell body, as confirmed by IF for caveolins. Occasionally, the so-called 'Ca2+-release units' (subplasmalemmal close associations of caveolae+endoplasmic reticulum+mitochondria) were detected in the dilations of cell processes. Electrophysiological single unit recordings of t-ICC in primary cultures indicated sustained spontaneous electrical activity (amplitude of membrane potentials: 57.26+/-6.56 mV). Besides the CD117/c-kit marker, t-ICC expressed variously CD34, caveolins 1&2, alpha-SMA, S-100, vimentin, nestin, desmin, NK-1. t-ICC were negative for: CD68, CD1a, CD62P, NSE, GFAP, chromogranin-A, PGP9.5, but IHC showed the possible existence of (neuro)endocrine cells in tubal interstitium. We call them 'JF cells'. In conclusion, the identification of t-ICC might open the door for understanding some tubal functions, e.g. pace-making/peristaltism, secretion (auto-, juxta- and/or paracrine), regulation of neurotransmission (nitrergic/purinergic) and intercellular signaling, via the very long processes. Furthermore, t-ICC might even be uncommitted bipotential progenitor cells.