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.

Subtotal colectomy with antiperistaltic cecoproctostomy for selected patients with slow transit constipation-from Chinese report

BACKGROUND AND AIMS

Total abdominal colectomy with ileorectal anastomosis (TAC-IRA) is recommended widely for the patients with severe, refractory slow transit constipation (STC). Subtotal colectomy with end-to-end antiperistaltic cecorectal anastomosis (Sarli procedure), an alternative for STC, has been paid particular attention. The purpose of this study was to retrospectively compare alterations of clinical functions and qualities of life between TAC-IRA and Sarli procedure.

METHODS

Seventeen patients with STC who underwent Sarli procedure and 20 patients with STC who underwent TAC-IRA were chosen for this study. Patient characteristics, operative data, postoperative data, alterations of clinical function, and quality of life were compared. The gastrointestinal quality of life index (GIQLI) survey was used to evaluate postoperative qualities of life.

RESULTS

At the mean 4-year follow-up (range 2-6 years), the frequency of daily bowel movement in the Sarli group was significantly less than that in the TAC-IRA group (2.4 +/- 0.9 vs. 3.4 +/- 0.8; P = 0.0014), and the Wexner continence scores were significantly lower in the Sarli group compared to the TAC-IRA group (4.3 +/- 1.8 vs. 5.8 +/- 1.9; P = 0.0223). However, the GIQLI score in Sarli group was higher than the TAC-IRA group (119.8 +/- 7.5 vs. 111.1 +/- 12.0, P = 0.0455). Post subtotal colectomy barium enema showed a sign of "reservoir" at the residual ascending colon and cecum.

CONCLUSIONS

Compared to the TAC-IRA, subtotal colectomy with end-to-end antiperistaltic cecoproctostomy for appropriately selected patients with STC resulted in relief of constipation, satisfactory functional outcome, and improved qualities of life.

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.

Radiologic evaluation of pelvic floor disorders

Several imaging modalities are available ranging from fluoroscopic techniques to ultrasonography and MRI for the evaluation of patients with pelvic floors disorders. High-resolution ultrasonography and MRI not only provide superior delineation of the pelvic floor anatomy but also reveal pathology and functional changes. This article focuses on standard imaging procedures including defecography, ultrasonography, and MRI and discusses its use in clinical practice by illustrating both normal and abnormal patterns.

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.

Pathophysiology of constipation in the older adult

This review provides information on the definition of constipation, normal continence and defecation and a description of the pathophysiologic mechanisms of constipation. In addition, changes in the anatomy and physiology of the lower gastrointestinal tract associated with aging that may contribute to constipation are described. MEDLINE (1966-2007) and CINAHL (1980-2007) were searched. The following MeSH terms were used: constipation/etiology OR constipation/physiology OR constipation/physiopathology) AND (age factors OR aged OR older OR 80 and over OR middle age). Constipation is not well defined in the literature. While self-reported constipation increases with age, findings from a limited number of clinical studies that utilized objective measures do not support this association. Dysmotility and pelvic floor dysfunction are important mechanisms associated with constipation. Changes in GI function associated with aging appear to be relatively subtle based on a limited amount of conflicting data. Additional research is warranted on the effects of aging on GI function, as well as on the timing of these changes.

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.

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.

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.

Chromosomal study of enteric glial cells and neurons by fluorescence in situ hybridization in slow transit constipation

The pathogenesis of slow transit constipation is still elusive. However, a genetic basis may be present. We investigated possible chromosomal abnormalities in enteric neurons and glial cells in patients with slow transit constipation. Colonic specimens from 22 patients with slow transit constipation undergoing surgery for intractable symptoms were obtained, and investigated by fluorescence in situ hybridization (FISH) for chromosomal abnormalities (chromosomes 1, 8, 17 and XY). These specimens were compared with of those obtained in 12 control subjects. Data analysis showed that 45.5% of patients displayed significant (>10%) aneusomy of chromosome 1 in enteric neurons. Aneusomy <10% for the same chromosome, but less than the cutoff suggested (10%), was found in enteric glial cells in 45.4% of the same patients. One patient had <10% aneusomy in enteric neurons for chromosome 8. No other abnormalities were found for the remaining probes, and no abnormalities were found in controls. We concluded that in a subgroup of patients with slow transit constipation a genetic basis may be present.

Pacemaker activity and inhibitory neurotransmission in the colon of Ws/Ws mutant rats

The aim of this study was to characterize the pacemaker activity and inhibitory neurotransmission in the colon of Ws/Ws mutant rats, which harbor a mutation in the c-kit gene that affects development of interstitial cells of Cajal (ICC). In Ws/Ws rats, the density of KIT-positive cells was markedly reduced. Wild-type, but not Ws/Ws, rats showed low- and high-frequency cyclic depolarization that were associated with highly regular myogenic motor patterns at the same frequencies. In Ws/Ws rats, irregular patterns of action potentials triggered irregular muscle contractions occurring within a bandwidth of 10-20 cycles/min. Spontaneous activity of nitrergic nerves caused sustained inhibition of muscle activity in both wild-type (+/+) and Ws/Ws rats. Electrical field stimulation of enteric nerves, after blockade of cholinergic and adrenergic activity, elicited inhibition of mechanical activity and biphasic inhibitory junction potentials both in wild-type and Ws/Ws rats. Apamin-sensitive, likely purinergic, inhibitory innervation was not affected by loss of ICC. Variable presence of nitrergic innervation likely reflects the presence of direct nitrergic innervation to smooth muscle cells as well as indirect innervation via ICC. In summary, loss of ICC markedly affects pacemaker and motor activities of the rat colon. Inhibitory innervation is largely maintained but nitrergic innervation is reduced possibly related to the loss of ICC-mediated relaxation.

Interstitial Cajal-like cells in human gallbladder

We describe here an interstitial Cajal-like cell type (ICLC) in human gallbladder, resembling the archetypal enteric interstitial cells of Cajal. Gallbladder ICLC were demonstrated in fresh preparations (tissue cryosections) using methylene-blue, and fixed specimens in Epon semi-thin sections stained with toluidine blue or transmission electron microscopy (TEM). The positive diagnosis of gallbladder ICLC was further verified by immunohistochemistry: CD117/c-kit, CD34, and another 16 antigens: vimentin, desmin, nestin, alpha-smooth muscle actin, NK-1, S-100, PGP-9.5, tau protein, chromogranin A, NSE, GFAP, CD1a, CD62-P, CD68, estrogen and progesterone receptors. Double immunostaining was performed for CD117, CD34 and CD117 and nestin, respectively. In fresh specimens, the spatial density of gallbladder ICLC was 100-110 cells/mm(2). ICLC mainly appeared beneath the epithelium and in muscularis (about 7%, and approximately 5%, respectively). In toto, ICLC represent in gallbladder approximately 5.5% of subepithelial cells. TEM showed that diagnostic criteria were fulfilled by ICLC. Moreover, TEM indicated that the main ultrastructural distinctive feature for ICLC, the cell processes, develop into the characteristic shape at a relatively early stage of development. It remains to be established if, in humans, ICLC are involved in gallbladder (dis)functions (e.g. pace-making, secretion (auto-, juxta- and/or paracrine), intercellular signaling, or stone formation).

The enteric nervous system in chagasic and idiopathic megacolon

Chagas disease frequently causes megacolon. We investigated the enteric nervous systems in patients with chagasic megacolon compared to idiopathic megacolon and controls. Surgical specimens were obtained from 12 patients with chagasic megacolon (1 woman, 11 men, age range 41 to 72 y) and 9 patients with idiopathic megacolon (3 women, 6 men, age range 39 to 68 y), undergoing surgery for intractable constipation. A control group of 10 patients (9 women, 1 man, age range 43 to 75 y) undergoing left hemicolectomy for nonobstructing colorectal cancer was also studied. Colonic sections were investigated by conventional and immunohistochemical methods, also taking into consideration the presence of lymphocytes. Compared to controls, the 2 megacolon groups showed a decrease of enteric neurons (not due to increased apoptosis) and of enteric glial cells (all more important in chagasic patients). The interstitial cells of Cajal subtypes were decreased but not absent in megacolons, although an increase of the intramuscular subtype was found, suggesting a possible compensative mechanism. An increased amount of fibrosis was found in the smooth muscle and the myenteric plexus of chagasic patients compared to the idiopathic megacolon and the control group. A mild lymphocytic infiltration of the enteric plexuses (more evident in Chagas disease) was also found in megacolons but not in controls. Patients with chagasic megacolon display important abnormalities of several components of the enteric nervous system. Similar alterations, although of lesser severity, may be found in patients with idiopathic megacolon.

Submucosal endoscopy with mucosal flap safety valve

BACKGROUND

There is no reliable endoscopic method to selectively resect deeper layers of the gut wall or to access the peritoneal cavity and prevent peritoneal soiling.

OBJECTIVES

To determine the technical feasibility and safety of submucosal endoscopy with mucosal flap (SEMF) in accessing the peritoneal cavity through a large full-thickness gastric-muscle-wall resection.

DESIGN

Ex vivo feasibility exploration and survival animal study.

SETTINGS

Ex vivo samples were obtained from fresh harvested organs. In vivo procedures were conducted with the pigs under standard general anesthesia.

INTERVENTIONS

High-pressure carbon dioxide (CO(2)) injection and balloon dissection created a large submucosal working space for insertion of a cap-fitted endoscope. By using the EMR cap, a full-thickness resection of the muscularis propria was performed. This full-thickness defect was sealed with the overlying mucosal flap and the use of hemoclips or tissue anchors.

RESULTS

By using the SEMF technique in the ex vivo experiment, the gastric wall was successfully traversed in each stomach after submucosal dissection and full-thickness resection of the musclaris. Similarly, by using the SEMF technique in the in vivo procedures, the peritoneal cavity was successfully accessed and the defect was completely sealed by using the mucosal flap. All animals survived 1 week after the procedure. Ulceration was noted in 3 pigs, and a small bowel injury was noted in 1 pig. Leak testing was negative in all stomachs.

CONCLUSIONS

By using the SEMF technique, submucosal space endoscopy and deep-layer gastric-wall resection were successfully performed. Furthermore, the mucosa overlying the dissected submucosal space served as a safe flap valve, preventing peritoneal leakage.

Apoptotic phenomena are not a major cause of enteric neuronal loss in constipated patients with dementia

Chronic constipation is a frequent symptom in patients with dementia, especially in those institutionalized. However, few data are available on the neuropathological aspects of the colon in such patients. We investigated the enteric neuropathology of the colon in two patients with longstanding dementia and intractable constipation, requiring surgery to alleviate symptoms. The results were compared to those obtained in 10 controls. No abnormalities were found at conventional histological examination, except for the presence of melanosis coli. Immunohistochemical evaluation revealed no important difference between patients and controls, except for a decreased number of enteric neurons in patients. However, this neuronal decrease was not associated to apoptotic phenomena, as observed in patients with severe idiopathic constipation. We concluded that in severely constipated patients with dementia the neuropathological abnormalities might be reconducted to a physiological neuronal decrease as a result of aging, and that the pathophysiological aspects of constipation in these subjects differ from those found in idiopathic constipation.

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.

Diagnostic testing in patients with chronic constipation

During the past few years, significant developments have taken place in the understanding and diagnosis of defecation disorders. Several innovative manometric, neurophysiologic, and radiologic techniques have been discovered, which have improved the accuracy of identifying the neuromuscular and pathophysiologic mechanisms of chronic constipation. Such approaches have led to improved management of these patients. In this review, we summarize and highlight recent advances in the utility of diagnostic testing of chronic constipation.

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.

Is pseudomelanosis coli a marker of colonic neuropathy in severely constipated patients?

AIMS

To study relationships between the number of pseudomelanosis coli cells and that of colonic enteric neurons and interstitial cells of Cajal, which are significantly reduced compared with controls in severely constipated patients. Pseudomelanosis coli is frequent in patients using anthraquinone laxatives. It is not known whether the prolonged use of these compounds damages the enteric nervous system in constipated patients.

PATIENTS AND METHODS

The relationship between the number of pseudomelanosis coli cells and that of colonic enteric neurons (as well as that of apoptotic enteric neurons) and of interstitial cells of Cajal was assessed by histological and immunohistochemical methods in 16 patients with chronic use of anthraquinone laxatives undergoing surgery for severe constipation unresponsive to medical treatment. No relationship was found between the number of pseudomelanosis coli cells and that of enteric neurons (and that of the apoptotic ones), nor of interstitial cells of Cajal, in either the submucosal or the myenteric plexus.

CONCLUSION

The use of anthraquinone laxatives, leading to the appearance of pseudomelanosis coli, is probably not related to the abnormalities of the enteric nervous system found in severely constipated patients.

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.

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.

Neural gastrointestinal electrical stimulation enhances colonic motility in a chronic canine model of delayed colonic transit

Neural gastrointestinal electrical stimulation (NGES) induces sequential contractions and enhances emptying in acute canine gastric and colonic models. This study was set to determine (i) the effect of NGES in a chronic canine model of delayed colonic transit and (ii) possible mechanism of action. Four pairs of electrodes were implanted in the distal colon of nine mongrel dogs. Delayed colonic transit was induced by diphenoxylate/atropine and alosetron. Transit was fluoroscopically determined by the rate of evacuation of radiopaque markers, and was tested twice in each dog, in random order, on and off stimulation. Two stimulation sequences, separated by 1 min, were delivered twice a day via exteriorized electrodes. Colonic manometry during stimulation was performed before and after intravenous (i.v.) injection of 1 mg of atropine. Complete evacuation of all markers was significantly shortened by NGES, from 4 days to 2 days, interquartile range 3-4 days vs 2-3 days, respectively, P = 0.016. NGES induced strong sequential contractions that were significantly diminished by atropine: 190.0 +/- 14.0 mmHg vs 48.7 +/- 19.4 mmHg, respectively (P < 0.001). NGES induces strong sequential colonic contractions and significantly accelerates movement of content in a canine model of delayed colonic transit. The effect is atropine sensitive.

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.

Downregulation of two novel genes in Sl/Sld and W(LacZ)/Wv mouse jejunum

Interstitial cells of Cajal (ICC) are the so-called pacemaker cells of the gut. W(LacZ)/Wv and Sl/Sld mice lack ICC surrounding the myenteric plexus (MP) in the jejunum. We compared the gene expression profile of wild type (WT) and W(LacZ)/Wv and Sl/Sld mice using suppression subtractive hybridization (SSH), generating a cDNA library of 1303 clones from which 48 unique sequences were differentially expressed with Southern blot. Among them, we identified heme oxygenase2, TROY, and phospholamban in ICC using immunohistochemistry. Using RT-qPCR, c-Kit and two new transcripts Dithp and prenylcysteine oxidase1 were significantly lower expressed in Sl/Sld and W(LacZ)/Wv versus WT. Prenylcysteine oxidase1 appeared cytotoxic for COS-7 cells and was highly expressed in liver while Dithp was mainly expressed in small intestine. The combination of SSH, Southern blot, RT-qPCR, and immunohistochemistry turned out to be a useful approach to identify rarely expressed genes and genes with small differences in expression.

Review article: uncomplicated diverticular disease of the colon

Diverticular disease of the colon is the fifth most important gastrointestinal disease in terms of direct and indirect health care costs in western countries. Uncomplicated diverticular disease is defined as the presence of diverticula in the absence of complications such as perforation, fistula, obstruction and/or bleeding. The distribution of diverticula along the colon varies worldwide being almost always left-sided and directly related to age in western countries and right-sided where diet is rich in fibre. The pathophysiology of diverticular disease is complex and relates to abnormal colonic motility, changes in the colonic wall, chronic mucosal low-grade inflammation, imbalance in colonic microflora and visceral hypersensitivity. Moreover, there can be genetic factors involved in the development of colonic diverticula. The use of non-absorbable antibiotics is the mainstay of therapy in patients with mild to moderate symptoms, and the effect of fibre-supplementation alone does not appear to be significantly different from placebo, although no definite data are available. More recently, alternative treatments have been reported. Mesalazine acts as a local mucosal immunomodulator and has been shown to improve symptoms and prevent recurrence of diverticulitis. In addition, probiotics have also been shown to be beneficial by re-establishing a normal gut microflora. In this study, the current literature on uncomplicated diverticular disease of the colon is reviewed.

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.

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.

Interstitial cells of Cajal, enteric nerves, and glial cells in colonic diverticular disease

BACKGROUND

Colonic diverticular disease (diverticulosis) is a common disorder in Western countries. Although its pathogenesis is probably multifactorial, motor abnormalities of the large bowel are thought to play an important role. However, little is known about the basic mechanism that may underlie abnormal colon motility in diverticulosis.

AIMS

To investigate the interstitial cells of Cajal (the gut pacemaker cells), together with myenteric and submucosal ganglion and glial cells, in patients with diverticulosis.

PATIENTS

Full thickness colonic samples were obtained from 39 patients undergoing surgery for diverticulosis. Specimens from tumour free areas of the colon in 10 age matched subjects undergoing surgery for colorectal cancer served as controls.

METHODS

Interstitial cells of Cajal were assessed using anti-Kit antibodies; submucosal and myenteric plexus neurones and glial cells were assessed by means of anti-PGP 9.5 and anti-S-100 monoclonal antibodies, respectively.

RESULTS

Patients with diverticulosis had normal numbers of myenteric and submucosal plexus neurones compared with controls (p = 0.103 and p = 0.516, respectively). All subtypes of interstitial cells of Cajal were significantly (p = 0.0003) reduced compared with controls, as were glial cells (p = 0.0041).

CONCLUSIONS

Interstitial cells of Cajal and glial cells are decreased in colonic diverticular disease, whereas enteric neurones appear to be normally represented. This finding might explain some of the large bowel motor abnormalities reported to occur in this condition.

C-kit immunopositive interstitial cells (Cajal-type) in human myometrium

Previous reports describing Cajal-like interstitial cells in human uterus are contradictory in terms of c-kit immunoreactivity: either negative (but vimentin-positive) in pregnant myometrium, or positive, presumably in the endometrium. The aim of this study was to verify the existence of human myometrial Cajal-like interstitial cells (m-CLIC). Six different, complementary approaches were used: 1) methylene-blue supravital staining of tissue samples (cryosections), 2) methylene blue and Janus green B vital staining (m-CLIC and mitochondrial markers, respectively), and 3) extracellular single-unit electrophysiological recordings in cell cultures, 4) non-conventional light microscopy on glutaraldehyde/osmium fixed, Epon-embedded semi-thin sections (less than 1 microm) stained with toluidine blue (TSM), 5) transmission electron microscopy (TEM), and 6) immunofluorescence (IF). We found m-CLIC in myometrial cryosections and in cell cultures. In vitro, m-CLIC represented approximately 7% of the total cell number. m-CLIC had 2-3 characteristic processes which were very long (approximately 60 microm), very thin (< or =0.5 microm) and moniliform. The dilated portions of processes usually accommodated mitochondria. In vitro, m-CLIC exhibited spontaneous electrical activity (62.4+/-7.22 mV membrane potentials, short duration: 1.197+/-0.04 ms). Moreover, m-CLIC fulfilled the usual TEM criteria, the so-called 'gold' or 'platinum' standards (e.g. the presence of discontinuous basal lamina, caveolae, endoplasmic reticulum, and close contacts between each other, with myocytes, nerve fibers and/or capillaries etc.). IF showed that m-CLIC express CD117/c-kit, sometimes associated with CD34, with vimentin along their processes. In conclusion, we describe myometrial Cajal-like interstitial cells that have affinity for methylene blue and Janus green B vital dyes, fulfill (all) TEM criteria, express CD117/c-kit and have spontaneous electric activity.

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.

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

BACKGROUND AND AIMS

The c-kit protooncogene receptor and its ligand stem cell factor regulate the proliferation and survival of germ cells as well as interstitial cells of Cajal (ICCs). Decreased numbers of ICCs and defects in its networks have been reported in the colon of patients with slow transit constipation (STC). However, little information about the c-kit messenger ribonucleic acid (mRNA) and protein expression in the constipated colon is available. The aim of this study was to determine whether the expression of c-kit mRNA and c-kit protein declined in the colon in STC.

PATIENTS AND METHODS

The sigmoid colonic samples from 12 patients with STC and from eight age-matched patients with non-obstructed colorectal cancer were used for this study. Expression of c-kit mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and expression of c-kit protein was detected by Western blot analysis.

RESULTS

Decreased expression of c-kit mRNA was demonstrated in the STC group compared with the control group. The ratio of c-kit and beta-actin was 1.26+/-0.32 in controls and 1.17+/-0.41 in the STC group (U=0.500, P=0.029). c-kit protein expression significantly declined in the STC group. The mean value of optical density was 162.97+/-5.43 in the control group and 96.64+/-8.80 in the STC group (U=0.000, P=0.021).

CONCLUSIONS

The data indicate that the expression of c-kit mRNA and c-kit protein significantly decreased in the colon of STC, suggesting that the c-kit signal pathway may play an important role in ICC reduction in STC.