Severe idiopathic constipation is associated with a distinctive abnormality of the colonic myenteric plexus

Upper gastrointestinal endoscopic findings in functional constipation and irritable bowel syndrome diagnosed using the Rome IV criteria: a cross-sectional survey during a medical check-up in Japan

BACKGROUND

The Rome IV criteria have been established as an international standard for diagnosing disorders of gut-brain interaction. In this study, we aimed to examine the upper gastrointestinal (GI) endoscopic findings and symptoms of subjects with functional constipation (FC) and irritable bowel syndrome (IBS) of individuals undergoing a medical check-up.

METHODS

A total of 13,729 subjects underwent a medical check-up at Osaka City University-affiliated clinic, MedCity21, between April 2018 and March 2019. Among the 5,840 subjects who underwent screening upper GI endoscopy and completed a questionnaire based on the Rome IV criteria, 5,402 subjects were consecutively enrolled after excluding subjects with a large amount of gastric residue (n = 6), those who had previously undergone partial or total gastrectomy (n = 40), or those with daily use of low-dose aspirin (n = 82), nonsteroidal anti-inflammatory drugs (n = 63), or acid secretion inhibitors (n = 308).

RESULTS

Robust Poisson regression analyses adjusted for age, sex, Helicobacter pylori infection status, alcohol intake, and smoking habits showed a significant association between FC and corpus erosion (adjusted prevalence ratio [aPR], 2.93; 95% confidence interval [CI], 1.51-5.67; p < 0.01) and red streaks (aPR, 3.83; 95% CI, 2.53-5.79; p < 0.01), whereas IBS was significantly associated with erosive gastritis (aPR, 8.46; 95% CI, 4.89-14.67; p < 0.01) and duodenitis (aPR, 7.28; 95% CI, 3.64-14.59; p < 0.01). Red streaks tended to be associated with IBS (aPR, 1.96; 95% CI, 1.00-3.83; p = 0.05). Subjects with IBS were the most to complain of both upper and lower GI symptoms and psychological symptoms, followed by those with FC and controls. IBS subjects with erosive gastritis or duodenitis had significantly more complaints of stomachache and feeling stressed than those without erosive gastritis or duodenitis (54.5% vs. 18.8%; p = 0.03 and 66.7% vs. 25.0%; p = 0.01).

CONCLUSIONS

Subjects with FC and IBS had a variety of upper GI and psychological symptoms. In the upper GI endoscopic findings, corpus erosion and red streaks were associated with FC, and erosive gastritis, duodenitis, and possibly red streaks were associated with IBS.

Use of radiographic and histologic scores to evaluate cats with idiopathic megacolon grouped based on the duration of their clinical signs

Since the duration of clinical signs could be used to identify cases of chronic constipation, in addition, prolonged duration is often associated with irreversible changes. Thus, the main objective of this study was to determine whether the duration of clinical signs of idiopathic megacolon in cats affected their diagnosis and prognosis after treatment. Medical records of cats that either had confirmed megacolon for an unknown cause (cat patients) or with normal bowels (control cats) were reviewed. Cat patients were grouped based on the duration of their clinical signs (constipation/obstipation) to cats <6 months and ≥6 months. For all feline patients, abdominal radiographs (for colonic indexes) and resected colon specimens (for histology) were assessed vs. control cats. Treatment applied to cat patients was also evaluated. Cat patients were older (p = 0.0138) and had a higher maximum colon diameter (MCD; mean 41.25 vs. 21.67 mm, p < 0.0001) and MCD/L5L ratio (1.77 vs. 0.98, p < 0.0001) than controls. Compared to cats with <6 months, cats ≥6 months showed a higher MCD (43.78 vs. 37.12 mm, p < 0.0001) and MCD/L5L ratio (1.98 vs. 1.67, p < 0.0001). Histologically, increased thickness of the smooth muscularis mucosa (54.1 vs. 22.33 μm, p < 0.05), and inner circular (743.65 vs. 482.67 μm, p < 0.05) and outer longitudinal (570.68 vs. 330.33 μm, p < 0.05) smooth muscular layers of the muscularis externa was noted only in cat patients with ≥6 months compared to controls. Similarly, fewer ganglion cells (0.93 vs. 2.87, p < 0.005) and more necrotized myocytes (2.25 vs. 0.07, p < 0.005) were observed in cats with ≥6 months. In contrast to <6 months, the majority of cats (94.4%) with ≥6 months duration did not show any response to medical treatment and therefore underwent surgery with favorable results. In conclusion, this study suggests that the duration of clinical signs should be considered in conjunction with maximal colon scores to evaluate cats for idiopathic megacolon and determine the level of treatment. Functional abnormalities of the colonic smooth muscles may be a possible cause of idiopathic megacolon in cats.

Chronic constipation in adults: Contemporary perspectives and clinical challenges. 1: Epidemiology, diagnosis, clinical associations, pathophysiology and investigation

BACKGROUND

Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled "Current perspectives in chronic constipation: a scientific and clinical symposium." In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting.

PURPOSE

This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular "hot topics" and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.

Characterization of gut contractility and microbiota in patients with severe chronic constipation

Chronic constipation (CC) is one of the most common gastrointestinal disorders worldwide. Its pathogenesis, however, remains largely unclear. The purpose of the present work was to gain an insight into the role of contractility and microbiota in the etiology of CC. To this end, we studied spontaneous and evoked contractile activity of descending colon segments from patients that have undergone surgery for refractory forms of CC. The juxta-mucosal microbiota of these colon samples were characterized with culture-based and 16S rRNA sequencing techniques. In patients with CC the spontaneous colonic motility remained unchanged compared to the control group without dysfunction of intestinal motility. Moreover, contractions induced by potassium chloride and carbachol were increased in both circular and longitudinal colonic muscle strips, thus indicating preservation of contractile apparatus and increased sensitivity to cholinergic nerve stimulation in the constipated intestine. In the test group, the gut microbiota composition was assessed as being typically human, with four dominant bacterial phyla, namely Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, as well as usual representation of the most prevalent gut bacterial genera. Yet, significant inter-individual differences were revealed. The phylogenetic diversity of gut microbiota was not affected by age, sex, or colonic anatomy (dolichocolon, megacolon). The abundance of butyrate-producing genera Roseburia, Coprococcus, and Faecalibacterium was low, whereas conventional probiotic genera Lactobacillus and Bifidobacteria were not decreased in the gut microbiomes of the constipated patients. As evidenced by our study, specific microbial biomarkers for constipation state are absent. The results point to a probable role played by the overall gut microbiota at the functional level. To our knowledge, this is the first comprehensive characterization of CC pathogenesis, finding lack of disruption of motor activity of colonic smooth muscle cells and insufficiency of particular members of gut microbiota usually implicated in CC.

The feasibility of laparoscopic subtotal colectomy with cecorectal anastomosis in community practice for slow transit constipation

BACKGROUND

The objective of this paper is to demonstrate if slow transit constipation (STC) can be accurately diagnosed, selecting patients appropriate for surgery, and safely perform laparoscopic subtotal colectomy with cecorectal anastomosis (CRA) with acceptable short and long-term outcomes in the setting of medically complex patients in a community practice.

METHODS

A retrospective study was performed at a private community surgical practice. Cohort involved 10 patients with up to 10 years in follow-up care with a diverse range of ages, body mass index (BMI) and medical conditions. Pre-operative work-up followed a comprehensive algorithm designed to rule out organic conditions and dyssynergistic defecation. The Sitz Mark Colon Transit Study was used to confirm STC. Laparoscopic subtotal colectomy with CRA techniques were used in all cases. Frequency of BMs and patient satisfaction over the study period were tabulated.

RESULTS

Average post-operative length of stay (LOS) was five days. One early major post-operative complication occurred, however there were no perioperative deaths, anastomotic leaks or revisions of the original surgery after discharge from the hospital. Two patients died due to non-bowel related causes. An incisional hernia was the single long-term complication. Initial post-operative BMs averaged several per day. In the 1-5 year follow-up, BMs tapered down from 1 to 2/day with some laxative use. By the 5th to 10th year follow-up, constipation occurred with 2-3 BMs/week, all requiring an osmotic laxative. Most patients, however, were satisfied with their bowel pattern.

CONCLUSION

Surgical candidates with severe STC can be accurately diagnosed and treated with minimally invasive surgery in community practice with acceptable outcomes as compared to outcomes published in the literature.

Clinical practice guidelines from the French National Society of Coloproctology in treating chronic constipation

Chronic constipation is a common symptom that regularly affects the quality of life of adult patients. Its treatment is mainly based on dietary rules, laxative drugs, perineal rehabilitation and surgical treatment. The French National Society of Coloproctology offers clinical practice recommendations on the basis of the data in the current literature, including those on recently developed treatments. Most are noninvasive, and the main concepts include the following: stimulant laxatives are now considered safe drugs and can be more easily prescribed as a second-line treatment; biofeedback therapy remains the gold standard for the treatment of anorectal dyssynergia that is resistant to medical treatment; transanal irrigation is the second-line treatment of choice in patients with neurological diseases, but it may also be proposed for patients without neurological diseases; and although interferential therapy may be a new promising treatment, it needs further evaluation.

Simultaneous degeneration of myenteric plexuses and pelvic parasympathetic colonic nerve in slow transit constipation: A case report

RATIONALE

Slow transit constipation (STC) is a common disease of which the etiology is still not clear. Multiple hypotheses have been proposed to explain STC, including autonomic neuropathy, disorders of the enteric nervous system and so forth. Morphological abnormalities of the enteric nerves of the colon in patients with STC have been extensively reported, while there have been no morphological reports focusing on extrinsic extramural fibers from the pelvic plexus to the distal colon (i.e., pelvic parasympathetic colonic nerve) in patients with STC.

PATIENT CONCERNS

Whether morphological changes of pelvic parasympathetic colonic nerve coexist with abnormalities of the enteric nerves of the colon in the patient with STC.

DIAGNOSIS

Slow transit constipation (STC).

INTERVENTIONS

The patient with STC underwent a partial colectomy (sigmoid colon and partial descending colon). The fibers of the myenteric plexuses within the removed colon and the myelinated fibers of the pelvic parasympathetic colonic nerve were observed under optical and electron-microscope.

OUTCOMES

The fibers of the myenteric plexuses showed vacuolated degeneration between the muscularis propria layer under optical microscope. Myelinated fibers of the pelvic parasympathetic colonic nerve showed obvious vacuolated degeneration under electron-microscopic examination.

LESSONS

Such a simultaneous neuropathy in both myenteric plexuses and extrinsic extramural nerves has not been documented previously. Our finding supports the notion that neuropathy remains the most plausible explanation for STC, in which nerve dysfunction might occur by way of a degenerative process.

Gastrointestinal Manifestations of Eating Disorders

Individuals with eating disorders, including anorexia nervosa and bulimia nervosa, may present with a range of gastrointestinal (GI) manifestations. The oral cavity, salivary glands, GI tract, pancreas, and liver can be impacted by nutritional restrictive and binge/purging behaviors. Complications are often reversible with appropriate nutritional therapy. At times, however, the complications in these disorders may be severe, irreversible and even life threatening. Given the often covert nature of eating disorders, the practitioner must be attentive to subtle clues that may indicate their presence. Extensive diagnostic evaluations of the GI manifestations of eating disorders should be used only when nutritional rehabilitation does not remedy the problems.

Clinical aspects of neurointestinal disease: Pathophysiology, diagnosis, and treatment

The enteric nervous system (ENS) is involved in the regulation of virtually all gut functions. Conditions referred to as enteric neuropathies are the result of various mechanisms including abnormal development, degeneration or loss of enteric neurons that affect the structure and functional integrity of the ENS. In the past decade, clinical and molecular research has led to important conceptual advances in our knowledge of the pathogenetic mechanisms of these disorders. In this review we consider ENS disorders from a clinical perspective and highlight the advancing knowledge regarding their pathophysiology. We also review current therapies for these diseases and present potential novel reparative approaches for their treatment.

Bowel Disorders

Functional bowel disorders are highly prevalent disorders found worldwide. These disorders have the potential to affect all members of society, regardless of age, gender, race, creed, color or socioeconomic status. Improving our understanding of functional bowel disorders (FBD) is critical as they impose a negative economic impact to the global health care system in addition to reducing quality of life. Research in the basic and clinical sciences during the past decade has produced new information on the epidemiology, etiology, pathophysiology, diagnosis and treatment of FBDs. These important findings created a need to revise the Rome III criteria for FBDs, last published in 2006. This manuscript classifies the FBDs into five distinct categories: irritable bowel syndrome (IBS); functional constipation (FC); functional diarrhea (FDr); functional abdominal bloating/distention (FAB/D); and unspecified FBD (U-FBD). Also included in this article is a new sixth category, opioid induced constipation (OIC) which is distinct from the functional bowel disorders (FBDs). Each disorder will first be defined, followed by sections on epidemiology, rationale for changes from prior criteria, clinical evaluation, physiologic features, psychosocial features and treatment. It is the hope of this committee that this new information will assist both clinicians and researchers in the decade to come.

Sonographic evaluation of gallbladder motility in children with chronic functional constipation

Background/Aims

Studies in adults suggest that constipation may not be a purely colonic pathology and may be a component of a generalized gastrointestinal (GI) motor disorder in which proximal GI motility can be impaired. Pediatric data are scarce, and the natural history of the disorder remains undefined. We aimed to evaluate gallbladder motility in a subset of Asian children with chronic functional constipation.

Methods

Abdominal ultrasound was performed on 105 children, including 55 patients (aged 3 to 13 years) with chronic functional constipation who met the inclusion criteria and 50 age- and gender-matched controls. The gallbladder contractility index was calculated based on the preprandial and postprandial gallbladder areas. Preprandial and postprandial values for gallbladder volume and wall thickness were evaluated.

Results

The mean value of the contractility index for the patients (15.77±24.68) was significantly lower than the mean value for the controls (43.66±11.58) (p=0.001). The mean postprandial gallbladder volumes and areas were larger in children with gallbladder hypomotility (p<0.05). The mean duration of constipation (4.8 months) was significantly higher (p=0.004) in the children with gall-bladder hypomotility.

Conclusions

Gallbladder motility is significantly impaired in children with chronic functional constipation. This study contributes to the understanding of the underlying pathophysiology, which will enable advancement in and improved management of children with chronic constipation and associated gallbladder hypomotility.

Efficacy and Safety of Prucalopride in Chronic Constipation: An Integrated Analysis of Six Randomized, Controlled Clinical Trials

BACKGROUND

Prucalopride, a selective, high-affinity 5-hydroxytryptamine 4 receptor agonist, stimulates gastrointestinal and colonic motility and alleviates common symptoms of chronic constipation (CC) in adults. The relative efficacy by gender has not been evaluated.

AIM

To evaluate the global efficacy and safety of prucalopride 2 mg daily in men and women with CC using data from six large, randomized, controlled clinical trials.

METHODS

Data were combined from six phase 3 and 4, double-blind, randomized, placebo-controlled, parallel-group trials. The primary efficacy endpoint was the percentage of patients with a mean of ≥3 spontaneous complete bowel movements (SCBMs) per week over 12 weeks of treatment. Safety was assessed throughout all the trials.

RESULTS

Overall, 2484 patients (597 men; 1887 women; prucalopride, 1237; placebo, 1247) were included in the integrated efficacy analysis and 2552 patients were included in the integrated safety analysis. Significantly more patients achieved a mean of ≥3 SCBMs/week over the 12 weeks of treatment in the prucalopride group (27.8 %) than in the placebo group [13.2 %, OR 2.68 (95 % CI 2.16, 3.33), p < 0.001]. Prucalopride had a favorable safety and tolerability profile. Efficacy and safety outcomes were not significantly different between men and women.

CONCLUSION

The integrated analysis demonstrates the efficacy and safety of prucalopride in the treatment of CC in men and women.

Factors predictive of treatment-emergent adverse events of prucalopride: an integrated analysis of four randomized, double-blind, placebo-controlled trials

Background/Aims

This integrated analysis aimed to identify the factors associated with the most frequently reported treatment-emergent adverse events (TEAEs) in Asian and non-Asian patients with chronic constipation (CC) who receive prucalopride or placebo over 12 weeks.

Methods

Pooled data from four randomized, double-blind, placebo-controlled, multicenter, phase III studies (NCT00488137, NCT00483886, NCT00485940, and NCT01116206) on patients treated with prucalopride 2 mg or placebo were analyzed. The associations between predictors and TEAEs were evaluated based on a logistic regression model.

Results

Overall, 1,821 patients (Asian, 26.1%; non-Asian, 73.9%) were analyzed. Prucalopride treatment was significantly associated with diarrhea, headache, and nausea (p<0.001), but not with abdominal pain, compared with placebo. Differences in the prevalence of TEAEs between prucalopride and placebo decreased greatly after the first day of treatment. Compared with non-Asians, Asians were more likely to experience diarrhea and less likely to develop abdominal pain, headache, and nausea. Prior laxative use, CC duration, and body weight were not predictive of any of these TEAEs.

Conclusions

Prucalopride treatment was positively associated with diarrhea, headache, and nausea. Asian patients tended to have a higher frequency of diarrhea but lower frequencies of headache, abdominal pain, and nausea compared with non-Asians.

Histological Findings in Resected Bowel of Motility-disordered Patients

Gastrointestinal (GI) motility disorders are prevalent conditions associated with pain and bowel dysfunction. Some motility-disordered patients with intractable symptoms have undergone bowel resection aimed at palliating their symptoms. Our objective was to describe a population of motility-disordered patients with histopathological abnormalities identified in full-thickness surgical biopsies. A retrospective cohort study using prospectively collected clinical data and pathology reports was conducted. All adult patients referred to a tertiary motility clinic from 1996 to 2011 who had bowel resection for motility disorder were consecutively sampled. Fisher's exact test was used. Ninety-seven patients were referred for motility disorder during this time and pathology reports were available for 62 patients (63.9%). Hypertrophy or hyperplasia of the myenteric plexus was reported in 13 patients (21.0%). These patients were predominantly females with constipation-dominant symptoms. They were more likely to have objective evidence of colonic inertia ( P = 0.01) than patients without myenteric plexus hypertrophy/hyperplasia. Consistent histopathologic abnormalities of myenteric plexus hypertrophy/hyperplasia were described in 21 per cent of patients with refractory GI motility disorders referred for surgical management. Our findings contrast with the hypoganglionosis reported in the slow transit constipation literature. Future studies are needed to systematically investigate these novel histologic findings through a follow-up immunohistochemical study of stored bowel specimens.

Chagasic megacolon: enteric neurons and related structures

Megacolon, the irreversible dilation of a colonic segment, is a structural sign associated with various gastrointestinal disorders. In its hereditary, secondary form (e.g. in Hirschsprung's disease), dilation occurs in an originally healthy colonic segment due to an anally located, aganglionic zone. In contrast, in chronic Chagas' disease, the dilated segment itself displays pathohistological changes, and the earliest and most prominent being found was massive loss of myenteric neurons. This neuron loss was partial and selective, i.e. some neurons containing neuronal nitric oxide synthase and/or vasoactive intestinal peptide (VIP) were spared from neuron death. This disproportionate survival of inhibitory neurons, however, did not completely correlate with the calibre change along the surgically removed, megacolonic segments. A better correlation was observed as to potentially contractile muscle tissue elements and the interstitial cells of Cajal. Therefore, the decreased densities of α-smooth muscle actin- and c-kit-immunoreactive profiles were estimated along resected megacolonic segments. Their lowest values were observed in the megacolonic zones itself, whereas less pronounced decreases were found in the non-dilated, transitional zones (oral and anal to dilation). In contrast to the myenteric plexus, the submucosal plexus displayed only a moderate neuron loss. Neurons co-immunoreactive for VIP and calretinin survived disproportionately. As a consequence, these neurons may have contributed to maintain the epithelial barrier and allowed the chagasic patients to survive for decades, despite their severe disturbance of colonic motility. Due to its neuroprotective and neuroeffectory functions, VIP may play a key role in the development and duration of chagasic megacolon.

Chronic constipation and treatment options (Review)

Chronic constipation (CC) is a highly prevalent heterogeneous disorder. Although CC is not known to be associated with the development of serious disease or with excess mortality, it considerably reduces the patients quality of life. In addition, it represents an economic burden to patients and society. The majority of patients with CC successfully manage the disorder by dietary management and the use of laxatives. Patients with functional CC (slow‑transit and non‑slow transit constipation) do not respond to laxatives and are a small fraction of the total population complaining of constipation. Regardless of the low number of these patients, the intractability of their symptoms causes psychological and social stress and greatly impairs their quality of life. Furthermore, these patients consume a disproportionate quantity of medical resources. It appears that these patients have a disturbance in the serotonin transmission system, which results in a cascade of alterations in a number of gut neuroendocrine hormones/transmitters. The effect of prucalopride, a serotonin receptor agonist, in this category of patients appears to be not only a pharmacological prokinetic action, but also a correction of a pre‑existing disturbance. Linaclotide, a member of the guanylin peptide family, binds to the ligand‑binding region of guanylate cyclase‑C on the luminal surface of gastrointestinal epithelia resulting in increased fluid secretion. This drug has also been found to be effective for the treatment of functional CC. In addition, biofeedback and sacral nerve stimulation are effective in the treatment of CC caused by pelvic floor disorders.

New perspectives in the diagnosis and management of enteric neuropathies

Chronic disturbances of gastrointestinal function encompass a wide spectrum of clinical disorders that range from common conditions with mild-to-moderate symptoms to rare diseases characterized by a severe impairment of digestive function, including chronic pain, vomiting, bloating and severe constipation. Patients at the clinically severe end of the spectrum can have profound changes in gut transit and motility. In a subset of these patients, histopathological analyses have revealed abnormalities of the gut innervation, including the enteric nervous system, termed enteric neuropathies. This Review discusses advances in the diagnosis and management of the main clinical entities--achalasia, gastroparesis, intestinal pseudo-obstruction and chronic constipation--that result from enteric neuropathies, including both primary and secondary forms. We focus on the various evident neuropathologies (degenerative and inflammatory) of these disorders and, where possible, present the specific implications of histological diagnosis to contemporary treatment. This knowledge could enable the future development of novel targeted therapeutic approaches.

Surgical management of colonic inertia

For the select small number of constipated patients that cannot be managed medically, surgical options should be considered. Increases in our knowledge of colorectal physiology and experience have fostered improvements in patient evaluation and surgical management. Currently, patients with refractory colonic inertia are offered total abdominal colectomy and ileorectal anastomosis, often with laparoscopic techniques. With proper patient selection, the results have been excellent for resolving the frequency and quality of bowel movements. However, symptoms such as bloating and abdominal pain, which may be related to irritable bowel syndrome rather than the colonic inertia, may persist.

An assessment of enteric nervous system and estroprogestinic receptors in obstructed defecation associated with rectal intussusception

BACKGROUND

The pathophysiological basis of obstructed defecation (OD) is still incompletely understood. In particular, few or no data are available concerning the enteric nervous system (ENS) in this condition. We investigated ENS abnormalities in patients with OD, undergoing surgery, together with the presence of estrogen (α and β) and progesterone receptors, and compare the results with those obtained in controls.

METHODS

Full-thickness rectal samples were obtained from 17 patients undergoing stapled transanal rectal resection for OD associated with rectal intussusception. Samples were analyzed by immunohistochemistry for enteric neurons, enteric glial cells, interstitial cells of Cajal (ICC), and for estrogen and progesterone receptors. Data were compared with those obtained in 10 controls.

KEY RESULTS

No differences between patients and controls were found for enteric neurons, whereas (compared with controls) OD patients displayed a significant decrease of enteric glial cells in both the submucous (P = 0.0006) and the myenteric (P < 0.0001) plexus. ICC were significantly increased in patients in the submucosal surface (P < 0.0001) and the myenteric area (P < 0.0001). Concerning estroprogestinic receptors, both were present on ICC in patients and controls. Estrogen receptors α and progesterone receptors were absent on enteric neurons and enteric glial cells in patients and controls, whereas estrogen receptors β were present in all controls and in 69% of patients' enteric neurons (P = 0.18) and in 12% of patients' glial cells (P = 0.0001).

CONCLUSIONS & INFERENCES

Patients with OD associated to rectal intussusception display abnormalities of the ENS and of estrogen receptors β.

Enteric neuromuscular pathology update

The recent development of consensus guidelines for the preparation and staining of tissues, the publication of the London Classification, and reviews of what is normal in the enteric neuromusculature have been significant steps forward in this field. Increased accessibility to full-thickness biopsies of the bowel wall facilitated by advances in laparoscopic surgery have also played a part in making the decision to ask for a tissue diagnosis easier. Better antibodies for immunohistochemistry and a better understanding of disease processes at work, such as those seen in filamin mutations, all help inform the range of information that can be gleaned from what is usually a very limited sample. Clinical phenotyping remains difficult in many patients, but the availability of specialist pathologic review and the standardization of staining between laboratories are leading to better defined histologic phenotypes, that inform, in turn, possible biological processes at work in these patients. In many instances, a diagnosis may come to light only after some time, and the retention of pathologic samples in paraffin wax, as is standard practice in most laboratories, is of great value in reassessing samples, often after many years, in the light of new advances. The highest quality information, and the best answer for the patient, is, as ever, achieved by close working relationships and excellent communication between clinicians and pathologists.

Diagnosis and treatment of chronic constipation--a European perspective

BACKGROUND

Although constipation can be a chronic and severe problem, it is largely treated empirically. Evidence for the efficacy of some of the older laxatives from well-designed trials is limited. Patients often report high levels of dissatisfaction with their treatment, which is attributed to a lack of efficacy or unpleasant side-effects. Management guidelines and recommendations are limited and are not sufficiently current to include treatments that became available more recently, such as prokinetic agents in Europe.

PURPOSE

We present an overview of the pathophysiology, diagnosis, current management and available guidelines for the treatment of chronic constipation, and include recent data on the efficacy and potential clinical use of the more newly available therapeutic agents. Based on published algorithms and guidelines on the management of chronic constipation, secondary pathologies and causes are first excluded and then diet, lifestyle, and, if available, behavioral measures adopted. If these fail, bulk-forming, osmotic, and stimulant laxatives can be used. If symptoms are not satisfactorily resolved, a prokinetic agent such as prucalopride can be prescribed. Biofeedback is recommended as a treatment for chronic constipation in patients with disordered defecation. Surgery should only be considered once all other treatment options have been exhausted.

Beyond hematoxylin and eosin: the importance of immunohistochemical techniques for evaluating surgically resected constipated patients

Chronic constipation requiring surgical ablation for intractability is often a frustrating condition from the pathologist's point of view. In fact, limiting the histological examination to only hematoxylin-eosin staining usually yields only the information that there are no abnormalities. By employing some simple and widely available immunohistochemical methods, discussed in this review, it is possible to gather data that may help in explaining the pathophysiological basis of constipation in these patients.

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.

Can "functional" constipation be considered as a form of enteric neuro-gliopathy?

Constipation has been traditionally viewed and classified as a functional or idiopathic disorder. However, evidence has been accumulating that suggests how constipation might be considered as due to abnormalities of the enteric nervous system, since alterations of this system, not evident in conventional histological examination, may be present in these patients. These abnormalities often consist in decrease or loss of the enteric glial cells, a pathological finding present in most types of constipation so far investigated. In this article we will discuss these evidences, and will try to consider constipation no more as a simple functional or idiopathic disorder but as a form of enteric neuro-gliopathy.

Partial, selective survival of nitrergic neurons in chagasic megacolon

One frequent chronic syndrome of Chagas’ disease is megacolon, an irreversible dilation of a colonic segment. Extensive enteric neuron loss in the affected segment is regarded as key factor for deficient motility. Here, we assessed the quantitative balance between cholinergic and nitrergic neurons representing the main limbs of excitatory and inhibitory colonic motor innervation, respectively. From surgically removed megacolonic segments of four patients, each three myenteric wholemounts (from non-dilated oral, megacolonic and non-dilated anal parts) was immunohistochemically triple-stained for choline acetyltransferase, neuronal nitric oxide synthase (NOS) and the panneuronal human neuronal protein Hu C/D. Degenerative changes were most pronounced in the megacolonic and anal regions, e.g. bulked, honeycomb-like ganglia with few neurons which were partly enlarged or atrophic or vacuolated. Neuron counts from each 15 ganglia of 12 megacolonic wholemounts were compared with those of 12 age- and region-matched controls. Extensive neuron loss, mainly in megacolonic and anal wholemounts, was obvious. In all three regions derived from megacolonic samples, the proportion of NOS-positive neurons (control: 55%) was significantly increased: in non-dilated oral parts to 61% (p = 0.003), in megacolonic regions to 72% (p < 0.001) and in non-dilated anal regions to 78% (p < 0.001). We suggest the chronic dilation of megacolonic specimens to be due to the preponderance of the nitrergic, inhibitory input to the intestinal muscle. However, the observed neuronal imbalance was not restricted to the dilated regions: the non-dilated anal parts may be innervated by ascending, cholinergic axons emerging from less affected, more anally located regions.

Therapy-refractory gastrointestinal motility disorder in a child with c-kit mutations

Constipation and fecal impaction are frequent and distressing complaints in pediatric gastroenterology. Especially in neurologically handicapped children, treatment of severe forms of slow-transit constipation (STC) can be difficult. In the majority of cases, STC is of unknown etiology. However, in recent years, there is growing evidence that interstitial cells of Cajal (ICCs), which serve as electrical pacemakers and generate spontaneous electrical slow waves in the gastrointestinal tract, might play an important role in the pathophysiology of STC. It remains unclear whether morphological ICC alterations seen in affected patients are based on congenital developmental anomalies, or whether they are a consequence of long-term constipation with secondary damage of the gastrointestinal nervous system. To the best of our knowledge, we present the first case of a patient with histological alterations in ICC morphology who displayed multiple alterations of c-kit at the level of mRNA. The protein encoded by c-kit is the receptor tyrosine kinase Kit (CD117), which is crucial for development and function of ICCs. Therefore, these findings provide a new explanation for congenital alterations of ICC development that result in gastrointestinal motility disorders.

Surgical management of constipation

For the select small number of constipated patients who cannot be managed medically, surgical options should be considered. Increases in our knowledge of colorectal physiology and experience have fostered improvements in evaluation and surgical management of patients. Currently, patients with refractory colonic inertia are offered total abdominal colectomy and ileorectal anastomosis. With proper selection of patients, the results have been excellent for resolving the frequency and quality of bowel movements. However, symptoms such as bloating and abdominal pain, which may be related to irritable bowel syndrome rather than the colonic inertia, may persist.

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

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

Mucosal nerve deficiency in chronic childhood constipation: a postmigration defect?

PURPOSE

Idiopathic chronic childhood constipation (ICCC) includes children who are severely constipated and who are resistant to behavioral or medical treatments. These children are distinguished from those with Hirschsprung's disease (HSCR) by the presence of enteric ganglia in rectal biopsy specimens. We investigated potential autonomic dysfunction by examining nerves in rectal mucosa.

METHODS

Immunostaining, confocal microscopy, and nerve analysis were performed on formalin-fixed and on Zamboni-fixed rectal biopsy specimens from children who were severely constipated. A computer-assisted neuron tracing technique was used to determine mucosal nerve density in Zamboni-fixed biopsy sections.

RESULTS

Nerves in Zamboni-fixed biopsy specimens were better stained than in formalin-fixed biopsy specimens. Regardless of fixation method, a deficiency of mucosal nerves was observed in ICCC when compared to children who are not constipated. Analysis of autotraced mucosal nerves confirmed the deficiency in ICCC biopsy specimens. Mucosal nerves were also severely deficient in patients with HSCR, even in transitional segments that contained ganglia.

CONCLUSIONS

Most patients with ICCC had decreased innervation of the rectal mucosa. Because mucosal nerves are critical for the peristaltic reflex, water secretion, and absorption, their deficiency can be related to patient constipation. Mucosal nerve density provides a pathologic basis for diagnosis of dysfunction in children who do not have HSCR but are chronically constipated. The study validates the neuron tracing method for objective evaluation of mucosal innervation.

Clinical trial: the efficacy, impact on quality of life, and safety and tolerability of prucalopride in severe chronic constipation--a 12-week, randomized, double-blind, placebo-controlled study

BACKGROUND

Chronic constipation may result in disabling symptoms, is often unsatisfactorily treated by laxatives and negatively impacts quality of life (QoL).

AIM

A randomized, double-blind, placebo-controlled, phase III trial to evaluate the efficacy and safety of a selective, high-affinity 5-HT(4) receptor agonist, prucalopride, in patients with chronic constipation [<or=2 spontaneous complete bowel movements (SCBMs)/week].

METHODS

Placebo, 2 or 4 mg prucalopride was administered orally once daily, for 12 weeks. The primary efficacy endpoint was the proportion of patients with >or=3 SCBMs/week, averaged over 12 weeks. Other assessments included BM frequency, constipation-related QoL and symptoms and tolerability.

RESULTS

Among 641 patients, significantly more patients taking prucalopride 2 or 4 mg (24%) than placebo (12%), achieved the primary efficacy endpoint (>or=3 SCBMs/week) or an increase of >or=1 SCBMs/week; 43% and 47% vs. 28% respectively. Prucalopride-treated patients also achieved significantly greater satisfaction with treatment and bowel function, and improved perception of constipation severity and constipation-related QoL, compared with placebo. Most frequent treatment-related adverse events were headache, abdominal pain, nausea and diarrhoea (mainly during day 1). There were no differences in comparison to placebo in the incidence of serious adverse effects or cardiovascular events.

CONCLUSION

Over 12 weeks, prucalopride was effective and well tolerated in chronic constipation.

Basic and clinical aspects of gastrointestinal pain

The gastrointestinal (GI) tract is a system of organs within multicellular animals which facilitates the ingestion, digestion, and absorption of food with subsequent defecation of waste. A complex arrangement of nerves and ancillary cells contributes to the sensorimotor apparatus required to subserve such essential functions that are with the exception of the extreme upper and lower ends of the GI tract normally subconscious. However, it also has the potential to provide conscious awareness of injury. Although this function can be protective, when dysregulated, particularly on a chronic basis, the same system can lead to considerable morbidity. The anatomical and molecular basis of gastrointestinal nociception, conditions associated with chronic unexplained visceral pain, and developments in treatment are presented in this review.

New techniques in the tissue diagnosis of gastrointestinal neuromuscular diseases

Gastrointestinal neuromuscular diseases are a clinically heterogeneous group of disorders of children and adults in which symptoms are presumed or proven to arise as a result of neuromuscular (including interstitial cell of Cajal) dysfunction. Common to most of these diseases are symptoms of impaired motor activity which manifest as slowed or obstructed transit with or without evidence of transient or persistent radiological visceral dilatation. A variety of histopathological techniques and allied investigations are being increasingly applied to tissue biopsies from such patients. This review outlines some of the more recent advances in this field, particularly in the most contentious area of small bowel disease manifesting as intestinal pseudo-obstruction.

[Fiber intake and colonic transit time in functional constipated patients]

BACKGROUND

Patients with functional constipation presenting no response to treatment using fibers supplement represents important clinical issue.

AIMS

To evaluate the relations among the amount of ingested fiber, the constipation intensity and the colonic transit time in patients with functional constipation.

METHODS

We evaluated 30 patients, presenting no response to treatment using fibers supplement, and 18 healthy volunteers conducting individual inquiry into fibers intake, constipation intensity and the total and segmental colonic transit evaluation using radiopaque markers.

RESULTS

In the constipated, despite the good level of fiber intake (26.3 +/- 12.9 g, constipated x 9.3 +/- 5,2 g, control), the symptoms of constipation was serious (score = 21.3 +/- 4.07). Mean total colonic transit was 58.8h. The colonic transit was slower in the constipated group (41.0 +/- 22.8 hours, constipated x 21.8 +/- 18.5h, control). In constipated patients with slow colonic transit (>58.8h) there were colonic inertia (eight), outlet constipation (one) and slow transit in left colon (one), and among constipated patients with normal colonic transit (<58.8h), there were isolated slow transit, in the right colon (nine), left colon (three) and in the rectosigmoid segment (eight). There were no relation among the amount of ingested fiber, constipation intensity and the colon transit.

CONCLUSIONS

In the functional constipation the gravity of symptoms does not depend only on the dietary fibers intake, which is not the only responsible for the differences in the colonic transit. The colonic transit can differentiate normal from constipated patients and, among them, those with altered transit that demand approaches distinct of fiber supplementation.

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.

Review article: molecular, pathological and therapeutic features of human enteric neuropathies

BACKGROUND

Considerable information has been gathered on the functional organization of enteric neuronal circuitries regulating gastrointestinal motility. However, little is known about the neuropathophysiological mechanisms underlying gastrointestinal motor disorders.

AIM

To analyse the most important pathological findings, clinical implications and therapeutic management of idiopathic enteric neuropathies.

METHODS

PubMed searches were used to retrieve the literature inherent to molecular determinants, pathophysiological bases and therapeutics of gastrointestinal dysmotility, such as achalasia, gastroparesis, chronic intestinal pseudo-obstruction, Hirschsprung's disease and slow transit constipation, to unravel advances on digestive disorders resulting from enteric neuropathies.

RESULTS

Current data on molecular and pathological features of enteric neuropathies indicate that degenerative and inflammatory abnormalities can compromise the morpho-functional integrity of the enteric nervous system. These alterations lead to a massive impairment in gut transit and result in severe abdominal symptoms with associated high morbidity, poor quality of life for patients and established mortality. Many pathophysiological aspects of these severe conditions remain obscure, and therefore treatment options are quite limited and often unsatisfactory.

CONCLUSIONS

This review of enteric nervous system abnormalities provides a framework to better understand the pathological processes underlying gut dysmotility, to translate this knowledge into clinical management and to foster the development of targeted therapeutic strategies.

Enteric neurodegeneration in ageing

The objective of this article is to review the clinical presentation and neurobiology of degeneration of the enteric nervous system with emphasis on human data where available. Constipation, incontinence and evacuation disorders are frequently encountered in the ageing population. Healthy lower gastrointestinal function is essential for successful ageing as it is critical to maintaining independence and autonomy to pursue further activity. One clinical expression of enteric neurodegeneration is constipation. However, the aetiology may be multifactorial as disturbances of epithelial, muscle or neural function may all result from neurodegeneration. There is evidence of loss of excitatory (e.g. cholinergic) enteric neurons and interstitial cells of Cajal, whereas inhibitory (including nitrergic) neurons appear unaffected. Understanding neurodegeneration in the enteric nervous system is key to developing treatments to reverse it. Neurotrophins have been shown to accelerate colonic transit and relieve constipation in the medium term; they are also implicated in maintenance programmes in adult enteric neurons through a role in antioxidant defence. However, their effects in ageing colon require further study. There is evidence that 5-HT(2) and 5-HT(4) mechanisms are involved in development, maintenance and survival of enteric neurons. Further research is needed to understand and potentially reverse enteric neurodegeneration.

Enteric neurodegeneration in ageing

The objective of this article is to review the clinical presentation and neurobiology of degeneration of the enteric nervous system with emphasis on human data where available. Constipation, incontinence and evacuation disorders are frequently encountered in the ageing population. Healthy lower gastrointestinal function is essential for successful ageing as it is critical to maintaining independence and autonomy to pursue further activity. One clinical expression of enteric neurodegeneration is constipation. However, the aetiology may be multifactorial as disturbances of epithelial, muscle or neural function may all result from neurodegeneration. There is evidence of loss of excitatory (e.g. cholinergic) enteric neurons and interstitial cells of Cajal, whereas inhibitory (including nitrergic) neurons appear unaffected. Understanding neurodegeneration in the enteric nervous system is key to developing treatments to reverse it. Neurotrophins have been shown to accelerate colonic transit and relieve constipation in the medium term; they are also implicated in maintenance programmes in adult enteric neurons through a role in antioxidant defence. However, their effects in ageing colon require further study. There is evidence that 5-HT(2) and 5-HT(4) mechanisms are involved in development, maintenance and survival of enteric neurons. Further research is needed to understand and potentially reverse enteric neurodegeneration.

Constipation

Chronic constipation is a common disorder manifested by a variety of symptoms. Assessments of colonic transit and anorectal functions are used to categorize constipated patients into three groups, i.e., normal transit or irritable bowel syndrome, pelvic floor dysfunction (i.e., functional defaecatory disorders) and slow transit constipation. 'Slow transit' constipation is a clinical syndrome attributed to ineffective colonic propulsion and/or increased resistance to propagation of colonic contents. Defaecatory disorders are caused by insufficient relaxation of the pelvic floor muscles or a failure to generate adequate propulsive forces during defaecation. Colonic transit is often delayed in patients with functional defaecatory disorders. Normal and slow transit constipation are generally managed with medications; surgery is necessary for a minority of patients with slow transit constipation. Functional defaecatory disorders are primarily treated with pelvic floor retraining using biofeedback therapy.

Ncx (Enx, Hox11L.1) is required for neuronal cell death in enteric ganglia of mice

BACKGROUND/PURPOSE

Ncx (Enx, Hox11L.1)-deficient (Ncx-/-) mice develop mega-ileo-ceco-colon with a larger number of neuronal cells in the enteric ganglia. We investigated mechanisms related to this abnormality and directed our attention to the effects on gastrointestinal tract functions.

METHODS

The number of NADPH diaphorase or cuprolinic blue-positive neuronal cells in the enteric ganglia was examined during growth of the mice. Neuronal cell death of enteric ganglia was assayed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling. Function of the gastrointestinal tract was determined by measuring excretion time of the barium chloride given into the stomach.

RESULTS

The number of neuronal cells decreased in control mice older than 2 weeks, and neuronal cell death was evident in the ganglia. However, the number of neuronal cells did not decrease in Ncx-/- mice, and cell death was rare. Excretion time of barium chloride was prolonged in all Ncx-/- mice examined and was improved by the administration of an inhibitor of nitric oxide synthase.

CONCLUSIONS

Ncx participates in cell death of enteric neurons. Motor abnormality of the gastrointestinal tract in Ncx-/- mice may be attributed to the large number of neuronal cells.

Idiopathic megacolon

This leading article refers to the paper by Meier-Ruge WA, Muller-Lobeck H, Stoss F, Bruder E. The pathogenesis of idiopathic megacolon. Eur J Gastroenterol Hepatol 2006; 18:1209-1215. We apologise to all concerned for the dissociation between the two papers, which was due to an administrative error. The pathogenesis of idiopathic megacolon is still unclear. Besides abnormalities of the enteric nervous system, alterations in the function of intestinal smooth muscle cells and connective tissue elements might play an important role. A permanent extension of the bowel diameter without concrete hints to its aetiology is termed idiopathic megacolon. Evidence exists that idiopathic megacolon comprises a heterogeneous group of conditions characterized by alterations of the enteric nervous system, smooth muscle cells and/or connective tissue. Innovative molecular techniques are needed to get further insights into the pathogenesis of these intestinal motility disorders.

The pathogenesis of idiopathic megacolon

BACKGROUND

Even today, the pathogenesis of idiopathic megacolon is still a subject of controversy. Anomalies of the gastrointestinal autonomous nervous system or of the smooth muscle of the muscularis propria are being considered.

METHODS

Sixty-three idiopathic megacolon resections between 1997 and June 2004 were investigated. The native specimens were coiled caudo-cranially and cryostat-cut. Connective tissue was stained with picric acid/Sirius red after Delauney fixation. Immunohistochemistry was performed for collagen types I, II, III and IV, as well as smooth muscle actin, vimentin, desmin fibronectin and CD117 for interstitial cells of Cajal. The enteric nervous system was examined by enzyme histochemistry for acetylcholine-esterase, lactate dehydrogenase, succinic dehydrogenase and nitroxide synthase.

RESULTS

Histologically, idiopathic megacolon was characterized by a total atrophy of the collagenous tendinous connective tissue membrane of the myenteric plexus and the tendinous collagen fibre net of the muscularis propria. Immunohistochemically, mainly collagen type III was missing in the muscularis propria. Interestingly, the incidence of idiopathic megacolon in those of the female sex was seven times more frequent than in the male sex. The myenteric plexus was normal in the majority of patients. Interstitial cells of Cajal, collagen II and IV, as well as smooth muscle actin, desmin and fibronectin showed no consistent alteration.

CONCLUSION

A normally structured tendinous fibre net of muscularis propria is an essential prerequisite for effective gut peristalsis. Atrophy of the tendinous fibre net abolishes peristalsis and allows for unlimited distension of the colon. A diagnosis of idiopathic megacolon can reliably be made on a collagen stain. The normal findings of myenteric plexus support the hypothesis that a primary metabolic defect of muscularis propria may be the underlying cause of idiopathic megacolon.

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 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.

Interstitial cells of cajal in patients with constipation due to total colonic inertia

Colonic wall contains interstitial cells of Cajal. In view of studies demonstrating that Cajal cells generate electric waves which are presumably responsible for colonic motor activity, and that these waves are absent in total colonic inertia, we investigated the hypothesis that colonic Cajal cells might be disordered in patients with total colonic inertia. The study comprised 28 patients (age 41.6 +/- 8.2 SD years, 19 women, 9 men) with total colonic inertia in whom total colectomy was performed. Colonic specimens obtained from normal segments of the excised colon of 24 cancer patients acted as controls. Specimens were subjected to c-kit immunohistochemistry. Controls for antisera specificity consisted of tissue incubated with normal rabbit serum that had been substituted for the primary antiserum. C-kit-positive branched Cajal-like cells were detected in the musculature of the normal colonic segments. They were distinguishable from the C-kit-negative smooth muscle cells and the C-kit-positive but unbranched mast cells. No Cajal cells were detected in colon of total colonic inertia patients. The absence of Cajal cells in patients with total colonic inertia can be assumed to explain the absence of electric waves and motile activity previously reported in these patients. Further studies are needed to investigate the cause of Cajal-cell absence.

Possible involvement of muscularis resident macrophages in impairment of interstitial cells of Cajal and myenteric nerve systems in rat models of TNBS-induced colitis

Resident macrophages are distributed in the network of interstitial cells of Cajal (ICC) and the myenteric nerve within the myenteric plexus. We evaluated changes in chemoattractant protein mRNA expression in macrophages and neutrophils, the ICC, nerve and macrophages in the myenteric plexus of model rats with TNBS-induced colitis. Chemoattractant proteins, MCP-1, GRO, MIP-2 and CINC-2alpha were upregulated in the colonic muscle layer after inflammation. Leukocyte infiltration and MPO activity were increased in the muscle layer. Electron microscopy indicated an irregular contour of the myenteric ganglia into which numerous macrophages had penetrated. Macrophages were also distributed near the ICC in the inflamed myenteric plexus. Immunohistochemistry showed that the ICC network and myenteric nerve system had disappeared from the inflamed region, whereas the number of resident macrophages was increased. TTX-insensitive, possibly ICC-mediated, rhythmic contractions of circular smooth muscle strips and enteric neuron-mediated TTX-sensitive peristalsis in the whole proximal colon tissue were significantly inhibited in the inflamed colon, indicating that the ICC-myenteric nerve system was dysfunctional in the inflamed muscle layer. Their accumulation around the myenteric nerve plexus and the ICC network suggests that macrophages play an important role in inducing intestinal dysmotility in gut inflammation.

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.