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

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.

Decreased density of interstitial cells of Cajal and neuronal cells in patients with slow-transit constipation and acquired megacolon

BACKGROUND

The pathophysiology of constipation is not clearly identified as yet, and the interstital cells of Cajal (ICC), known to generate the slow wave activity and to be involved in intestinal neurotransmission and the enteric nervous system (ENS), are suspected to play an important role. The aims of the present study were to assess the distribution of ICC and neuronal cells of ENS in patients with slow-transit constipation and acquired megacolon.

METHODS

Sigmoid colon specimens were obtained from patients who underwent colectomy due to slow-transit constipation (n = 10), acquired megacolon (n = 9) and non-obstructive colon cancer (n = 10) as a control group. The ICC were visualized by c-Kit immunohistochemistry and neuronal cells of the ENS were demonstrated by protein gene product (PGP) 9.5. Density of cells stained by c-Kit and PGP 9.5 was calculated as percent area (area stained/area of X-Y plane) x 100, when images were collected at a magnification of x40 objective, with maximum area examined in the horizontal X-Y plane of 400 microm x 400 microm using an image analyzer.

RESULTS

The densities of ICC and PGP 9.5 reactive neuronal structures were significantly decreased in all layers of sigmoid colon specimens in patients with slow-transit constipation and acquired megacolon, compared with that of the control group. However, there was no statistically significant difference in either the density of ICC or that of neuronal structures between the patients with slow-transit constipation and acquired megacolon.

CONCLUSIONS

Slow-transit constipation and acquired megacolon were associated with alteration of ICC and neuronal cells of ENS in the sigmoid colon.

Ambulatory 24-hour colonic manometry in slow-transit constipation

BACKGROUND

The colonic neuromuscular dysfunction in patients with constipation and the role of colonic manometry is incompletely understood.

AIM

To study prolonged colonic motility and assess its clinical significance.

METHODS

Twenty-four-hour ambulatory colonic manometry was performed in 21 patients with slow-transit constipation and 20 healthy controls by placing a 6-sensor solid-state probe up to the hepatic flexure. Quantitative and qualitative manometric analysis was performed in 8-h epochs. Patients were followed up for 1 yr.

RESULTS

Constipated patients showed fewer pressure waves and lower area under the curve (p < 0.05) than controls during daytime, but not at night. Colonic motility induced by waking or meal was decreased (p < 0.05) in patients. High-amplitude propagating contractions (HAPCs) occurred in 43% of patients compared to 100% of controls and with lower incidence (1.7 vs 10.1, p < 0.001) and propagation velocity (p < 0.04). Manometric features suggestive of colonic neuropathy were seen in 10, myopathy in 5, and normal profiles in 4 patients. Seven patients with colonic neuropathy underwent colectomy with improvement. The rest were managed conservatively with 50% improvement at 1 yr.

CONCLUSIONS

Patients with slow-transit constipation exhibited either normal or decreased pressure activity with manometric features suggestive of colonic neuropathy or myopathy as evidenced by absent HAPC or attenuated colonic responses to meals and waking. In refractory patients, colonic manometry may be useful in characterizing the underlying pathophysiology and in guiding therapy.

Abnormality of peptide YY and pancreatic polypeptide immunoreactive cells in colonic mucosa of patients with colonic inertia

The etiopathology of colonic inertia remains unclear. Current studies show that pancreatic polypeptide-fold family members can serve as regulators of colonic motility and transit. Thus, the cells containing these peptides on colonic mucosa could be abnormal in patients with colonic inertia. We aimed to evaluate the immunocytochemical staining of peptide YY (PYY) and pancreatic polypeptide (PP) immunoreactive cells, and detect if alteration of these cells relates to an increase in enterochromaffin cells (EC) demonstrated by chromogranin A (CgA), in the colonic mucosa of patients with colonic inertia. Nineteen consecutive patients (18 female, 1 male; age, 43.7+/-11.5 years) who underwent subtotal colectomy for colonic inertia were assessed. The control group consisted of 15 patients (all female; age, 50.7+/-12.5 years) who underwent colonoscopic biopsies from the right and left colon for indications other than constipation, inflammatory bowel diseases, diarrhea, or neoplasm. Hollande's-fixed, paraffin-embedded tissues of both right and left colons were collected. Immunocytochemical staining of PYY, PP, or CgA was performed on 4-microm tissue sections with the respective primary rabbit antibody, the biotinylated secondary antibody, and enzyme-labeled streptavidin. The average number of positive cells per microscopic field (200x) was calculated. Positive cells were classified as strongly, moderately, and weakly staining. The proportion of the variously stained cells is expressed as the percentage of the entire positive cell population. On both sides of the colon, the percentages of strongly and moderately stained PYY positive cells were higher in the patient group compared to the controls (right side, 10.6 and 27.3 vs. 6.1 and 18.7%, respectively; left side, 9.4 and 23.9 vs. 6.2 and 23.1%, respectively) (P < 0.01). Furthermore, in the patients with colonic inertia, the percentages of strongly and moderately stained PYY-positive cells were higher in the right-side colon than in the left (P < 0.01). There was no difference in the number of PYY-positive cells between the patients and the controls. PP-positive cells were very rare in all specimens and were found in 7 of 19 cases (36.84%) in the right-side colon and 16 of 19 (84.21%) in the left-side colon in the patient group (P < 0.01, left vs. right). In contrast, the number of EC in the left colon of patients (16.8+/-10.2) was significantly higher than that in the right side (9.4+/-6.0) (P < 0.01) or that in the left side in the control group (10.4+/-6.0) (P < 0.05). We conclude that in the colonic mucosa of patients with colonic inertia, PYY-positive cells present with higher immunoreactivity, indicating that they may contain more hormones, especially on the right side of the colon. However, the PPY- and PP-positive cells did not relate to the increased EC. and It is therefore suggested that the altered PYY in the colonic mucosa may partially contribute to the etiopathology of colonic inertia.

Human enteric neuropathies: morphology and molecular pathology

The aim of this study is to review current understanding of the molecular and morphological pathology of the enteric neuropathies affecting motor function of the human gastrointestinal tract and to evaluate the described pathological entities in the literature to assess whether a new nosology may be proposed. The authors used PUBMED and MEDLINE searches to explore the literature pertinent to the molecular events and pathology of gastrointestinal motility disorders including achalasia, gastroparesis, intestinal pseudo-obstruction, colonic inertia and megacolon in order to characterize the disorders attributable to enteric gut neuropathies. This scholarly review has shown that the pathological features are not readily associated with clinical features, making it difficult for a patient to be classified into any specific category. Individual patients may manifest more than one of the morphological and molecular abnormalities that include: aganglionosis, neuronal intranuclear inclusions and apoptosis, neural degeneration, intestinal neuronal dysplasia, neuronal hyperplasia and ganglioneuromas, mitochondrial dysfunction (syndromic and non-syndromic), inflammatory neuropathies (caused by cellular or humoral immune mechanisms), neurotransmitter diseases and interstitial cell pathology. The pathology of enteric neuropathies requires further study before an effective nosology can be proposed. Carefully studied individual cases and small series provide the basic framework for standardizing the collection and histological evaluation of tissue obtained from such patients. Combined clinical and histopathological studies may facilitate the translation of basic science to the clinical management of patients with enteric neuropathies.

Anismus: a marker of multi-site functional disorders?

PURPOSE

This study was undertaken to assess the clinical significance of anismus in patients who complain of constipation.

PATIENTS AND METHODS

Thirty control subjects and 93 consecutive patients complaining of functional constipation took part in the study. Colonic transit time study and anorectal manometry were performed. Questions about depression and urinary and sexual diseases were added to a questionnaire based on the Rome II criteria, and visual analog scales about four items (constipation, diarrhoea, abdominal bloating and abdominal pain).

RESULTS

Constipated patients have lower threshold sensation volume, lower constant sensation volume, and lower maximum tolerable volume than controls. Thirty-seven patients (40%) were found to have anismus, based on anorectal manometry. No significant difference was found between constipated patients with anismus and constipated patients without anismus, using anorectal manometry. Constipated patients had longer colorectal transit time than controls, but neither total nor segmental colonic transit time was correlated with the presence or absence of anismus. In patients with anismus, a higher frequency of oesophageal symptoms, dysmotility-like dyspepsia, aerophagia, functional bowel disorders, functional abdominal pain, soiling, and dyschezia was found. In addition, a higher frequency of urinary complaints, sexual complaints, and depression was found. Anismus was associated with increased awareness of constipation, abdominal bloating, and abdominal pain, but not with diarrhoea.

Gallbladder and gastric motility in patients with idiopathic slow-transit constipation

OBJECTIVE

Idiopathic slow-transit constipation (STC) has been suggested to be a pangastrointestinal motility disorder. We investigated scintigraphically whether motility in the gallbladder and stomach was impaired in slow-transit constipation.

METHODS

Twenty-four patients with STC were studied. Colon transit time, gallbladder motility, and solid-phase gastric emptying were measured by scintigraphy.

RESULTS

Gallbladder dysmotility was observed in 8 of 18 (44.4%) patients. Mean gallbladder ejection fraction was 41.6 +/- 13.6% (range, 16.3-67.0%). Gastric emptying was delayed in 9 of 18 (50%) patients. Mean solid-phase gastric half-emptying time was 75 minutes. STC may be associated with impaired function of other gastrointestinal organs. Approximately half of patients with STC presented gallbladder or gastric dysmotility.

CONCLUSION

STC may not be a pure colonic abnormality; it may be a component of a pangastrointestinal tract motility disorder involving several organs.

Colonic motor activity in slow-transit idiopathic constipation as identified by 24-h pancolonic ambulatory manometry

Colorectal motor activity in slow-transit idiopathic constipation has not been fully evaluated under physiological conditions. The aim of this study was to evaluate colorectal motor activity in chronic idiopathic constipation using 24-h ambulant pancolonic manometry. Ten healthy volunteers (six females) 19-31 years of age, and eight females 25-46 years of age with slow-transit idiopathic constipation were studied. Motor activity was measured using two custom-made silicone-coated catheters, each with five solid-state pressure transducers. Bowel preparation or sedation was not used. Frequency of high-amplitude propagated contractions was reduced in chronic idiopathic constipation, median 1.9/24 h vs 6/24 h (P = 0.01). Contractile frequency of low-amplitude complexes was reduced throughout the colon in slow-transit idiopathic constipation (P < 0.0001). The interval between contractile complexes was reduced in the transverse colon and splenic flexure (P < 0.0001). This study demonstrates that colonic motor activity is abnormal in slow-transit idiopathic constipation; decreased motor activity leads to a reduction in propulsion of intraluminal contents.

Chronic idiopathic slow transit constipation: pathophysiology and management

OBJECTIVE

Patients with idiopathic slow-transit constipation comprise a small proportion of the total population complaining of constipation. The purpose of this review is to present an update of pathophysiology of this disorder and its application in clinical management.

METHODS

Medline was used to search English language articles published up to the end of September 2002 on the subject of slow-transit constipation.

RESULTS AND CONCLUSIONS

Patients with idiopathic slow-transit constipation can be divided into 2 subgroups: 1. patients with normal proximal gastrointestinal motility and with onset of constipation in connection with childbirth or pelvic surgery. This subgroup may benefit from consideration of surgical treatment; 2. patients who have a dysfunctional enteric nervous/neuroendocrine system and exhibit colonic dysmotility as part of a generalised gastrointestinal dysmotility. Surgical approach in this subgroup seems to be unhelpful and medical treatment appears to be a better approach.

Fecoflowmetric evaluation of anorectal function and ability to defecate in children with idiopathic chronic constipation

Idiopathic chronic constipation (ICC) is one of the most common clinical conditions in children. The pathophysiology is multifactorial and differs from case to case. To investigate the relationship between anorectal motility (ARM) and clinical course in children with ICC, anorectal function was evaluated using fecoflowmetry in nine children aged 2-14 years (mean 6.1). Three were boys and six were girls. Pressure fluctuations in the rectum and anal canal were simultaneously recorded during saline (250-500 ml) infusion into the rectum. The dynamics of defecation were evaluated using recordings of the saline evacuation curve from the rectum in each patient. Seven patients showed periodic contractions of the rectum accompanied (five) or unaccompanied (two) by relaxations of the anal canal during saline infusion. These patients achieved comfortable spontaneous defecation during follow-up periods ranging from 5 to 20 months. The other two exhibited no rectal contractions in spite of relaxations of the anal canal, and did not respond well to long-term medical management. In eight patients segmental fecoflowmetric curves showed a significantly lower flow rate and longer evacuation time than those of controls. Fecoflowmetry is a simple and non-invasive technique for evaluation of the ability to defecate. Disturbances of ARM may play an important role in patients with severe ICC. When evaluating anorectal function in children with chronic constipation, more attention should be paid to ARM and fecodynamics.

Constipation: evaluation and treatment

Constipation is a common clinical problem that comprises a constellation of symptoms that include excessive straining, hard stools, feeling of incomplete evacuation, use of digital maneuvers, or infrequent defecation. Although many conditions, such as metabolic problems, fiber deficiency, anorectal problems, and drugs, can cause constipation, when excluded functional constipation consists of two subtypes: slow-transit constipation and dyssynergic defecation. Some patients with irritable bowel syndrome may exhibit features of both types of constipation. The Rome criteria for functional constipation together with modifications proposed here for dyssynergic defecation may serve as useful guidelines for making a diagnosis. Recent advances in technology, together with a better understanding of the underlying mechanisms, have led to real progress in the diagnosis of this condition. Management options are limited, however, and evidence to support these treatments is only modest. The treatment is primarily medical; surgical options should be reserved for refractory disease and after careful diagnostic work-up. Although laxatives remain the mainstay of therapy, prokinetics that are colon-selective are optimal for treating patients with slow-transit constipation, but they are not yet available for clinical use. Recent controlled trials, however, are promising. Biofeedback therapy is the preferred treatment for patients with dyssynergia, but is not widely available. In the near future, user-friendly biofeedback programs including home therapy may facilitate wider use of these methods for patients with dyssynergic defecation.

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Is chronic use of stimulant laxatives harmful to the colon?

Although stimulant laxatives cause structural damage to surface epithelial cells that is of uncertain functional significance, there is no convincing evidence that their chronic use causes structural or functional impairment of enteric nerves or intestinal smooth muscle. Nor are there reliable data to link chronic use of stimulant laxatives to colorectal cancer and other tumors. The risks of laxative abuse have been overemphasized, and this has minimized their rational use by physicians. Stimulant laxatives may be used chronically when patients fail to respond adequately to bulk or osmotic laxatives alone. These can be combined with bulk or osmotic laxatives in sufficient amounts to soften the stool, or they can be used alone, according to clinical circumstances. The dose of such agents should be titrated to effect. Bisacodyl may be used if anthraquinone laxatives are unsatisfactory.

Enteric nerves and interstitial cells of Cajal are altered in patients with slow-transit constipation and megacolon

BACKGROUND & AIMS

A variety of gastrointestinal motility disorders have been attributed to alterations of interstitial cells of Cajal and malformations of the enteric nervous system. This study evaluates both the distribution of interstitial cells of Cajal and the pathohistology of the enteric nervous system in 2 severe human colorectal motility disorders.

METHODS

Colonic specimens obtained from patients with slow-transit constipation (n = 11), patients with megacolon (n = 6), and a control group (n = 13, nonobstructing neoplasia) were stained with antibodies against c-kit (marker for interstitial cells of Cajal) and protein gene product 9.5 (neuronal marker). The morphometric analysis of interstitial cells of Cajal included the separate registration of the number and process length within the different regions of the muscularis propria. The structural architecture of the enteric nervous system was assessed on microdissected whole-mount preparations.

RESULTS

In patients with slow-transit constipation, the number of interstitial cells of Cajal was significantly decreased in all layers except the outer longitudinal muscle layer. The myenteric plexus showed a reduced ganglionic density and size (moderate hypoganglionosis) compared with the control group. Patients with megacolon were characterized by a substantial decrease in both the number and the process length of interstitial cells of Cajal. The myenteric plexus exhibited either complete aganglionosis or severe hypoganglionosis.

CONCLUSIONS

The enteric nervous system and interstitial cells of Cajal are altered concomitantly in slow-transit constipation and megacolon and may play a crucial role in the pathophysiology of colorectal motility disorders.

Long-term response to subtotal colectomy in colonic inertia

The purpose of this study was to determine the long-term outcome of patients who had previously undergone subtotal colectomy for severe idiopathic constipation at the University of Florida between 1983 and 1987. In addition, we aimed to determine whether preoperative motility abnormalities of the upper gastrointestinal tract are more common among those patients who have significant postoperative complications after subtotal colectomy. We evaluated 13 patients who underwent subtotal colectomy for refractory constipation between 1983 and 1987 at the University of Florida. Preoperatively, all patients exhibited a pattern consistent with colonic inertia as demonstrated by means of radiopaque markers. Each patient was asked to quantitate the pain intensity and frequency of their bowel movements before and after surgery. In seven patients an ileosigmoid anastomosis was performed, whereas in six patients an ileorectal anastomosis was used. Abdominal pain decreased after subtotal colectomy. Patients with abnormal upper gastrointestinal motility preoperatively experienced greater postoperative pain than those with normal motility regardless of the type of anastomosis. In addition, the number of postoperative surgeries was similar in those patients with abnormal upper motility compared to those with normal motility. Overall, the total number of bowel movements per week increased from 0.5 +/- 0.03 preoperatively to 15 +/- 4.5 (P < 0.007) postoperatively. The results of our study suggest that patients with isolated colonic inertia have a better long-term outcome from subtotal colectomy than patients with additional upper gastrointestinal motility abnormalities associated with their colonic inertia.

Variability in serotonin and enterochromaffin cells in patients with colonic inertia and idiopathic diarrhoea as compared to normal controls

AIM: To evaluate differences in distribution, density and staining intensity of enterochromaffin cells (EC) and serotonin cells (SC) in the colonic mucosa of patients with colonic inertia (CI), idiopathic diarrhoea (ID) and a control group. METHODS: Three groups were studied: 19 patients' colons after subtotal colectomy for CI, and 17 patients' biopsies for diarrhoea (>3 bowel movements/day) with histological findings of normal mucosa (excluding microscopic, eosinophillic and collagenous colitis). The third group included 15 patients who underwent colonoscopy and biopsy for indications other than constipation, inflammatory bowel disease, diarrhoea or neoplasm (control group). Specimen blocks were obtained in each case from the right and left colon. Immunohistochemical staining for EC and SC were done on 4 micro m sections from Hollandes fixed, paraffin embedded tissues with primary rabbit antibody against chromagranin A or serotonin, and biotynylated secondary antibody and enzyme labelled streptavidin. RESULTS: The number of EC in the mucosa of the left colon in patients with CI (16.8 +/- 10.2) and ID (19.9 +/- 9.7) were significantly higher than they were on the right side (CI: 9.4 +/- 6.0, ID: 12.1 +/- 5.3). However, there were no significant differences between the left and right sides in the control group (L: 10.3 +/- 5.3; R: 13.4 +/- 7.6). Although the quantity of EC in the left colon in both patients with CI (P < 0.05) and ID (P < 0.01) were significantly higher than in the controls, there was no significant difference between CI and ID. In both the right and left colon, the percentage of EC with low positive density was significantly higher (P < 0.01) while those cells with moderate or low staining intensity were significantly lower in patients with CI than in either patients with ID or control group. In patients with CI, the quantity of SC in the mucosa of the left colon (12.1 +/- 6.4) was higher than in the right (CI: 7.9 +/- 3.6; control 4.6 +/- 3.3; ID 4.6 +/- 2.9) (P = 0.0057). In contrast there was no significant difference in SC in either the ID or control groups. The quantity of SC in both sides of the colon was significantly higher both in patients with CI as compared to the control group (P < 0.01) and patients with CI vs. patients with ID (L = P < 0.01; R = P < 0.05). There was a significantly positive correlation between the numbers of EC and SC in patients with CI (L: r = 0.5425, P < 0.05; R: r = 0.745, P < 0.01). CONCLUSION: In patients with CI, EC increases possibly due to an increase in SC. Conversely, in patients with ID, the EC increase results from peptides other than SC. Our results suggest that different aetiological factors contribute to ID and CI.

Study of the motile activity of the colon in rectal inertia constipation

BACKGROUND

We have recently demonstrated that rectal distension effected left colonic contraction, which probably acts to feed the rectum with fecal matter each time the rectum distends and evacuates its contents. This effect was postulated to occur through the recto-colic reflex. As the colonic status in rectal inertia constipation was scarcely addressed in the literature, we investigated this point.

METHODS

The response of the colonic pressure to rectal balloon distension in increments of 10 mL of water was studied in 38 patients with rectal inertia constipation (IC) (age 42.6 +/- 14.3 years, 29 women) and 12 healthy volunteers (40.9 +/- 12.2 years, nine women). The rectal and colonic pressures were measured by saline-perfused tubes connected to a pneumohydraulic infusion system. The rectum was distended by a condom applied to the end of a 10-F catheter.

RESULTS

The rectal and left colonic resting pressures were significantly lower in the patients than in the controls (P < 0.5, P < 0.05, respectively). In the healthy volunteers, rectal distension up to first rectal sensation produced no significant rectal or colonic pressure changes (P > 0.05, P > 0.05). At urge, rectal and left colonic pressures increased significantly (P < 0.001, P < 0.001, respectively), but there were no changes in the right colonic pressure (P > 0.05). The colonic response lasted as long as the rectum was distended. In IC, patients did not perceive the first rectal or urge sensation up to a rectal balloon filling of 300 mL; there was no rectal or colonic pressure response (P > 0.05, P > 0.05).

CONCLUSION

In normal subjects, left colonic contraction on rectal distension probably acts to feed the rectum with fecal material. In IC, the low left colonic resting pressure assumedly points to left colonic hypotonia which appears to aggravate the constipation produced by the inertic rectum. Furthermore, non-response of the left colon to rectal distension probably impedes rectal feeding with fecal matter and enhances constipation.

Enteric glial cells. An upstream target for induction of necrotizing enterocolitis and Crohn's disease?

As a direct consequence of the sophisticated arrangement of its intrinsic neurons, the gastrointestinal tract is unique among peripheral organs, in its ability to mediate its own reflexes. Neurons of the enteric nervous system are intimately associated with enteric glial cells. These supporting cells do not resemble Schwann cells, the glial cell found in all other parts of the peripheral nervous system, but share many similarities with astrocytes of the central nervous system. Ablation of enteric glial cells in adult transgenic mice has demonstrated that these cells are essential to maintain the integrity of the small intestine. Acute loss of enteric glial cells induces massive pathological changes with similarities to necrotizing enterocolitis (NEC) and early Crohn's disease. These human conditions share some mechanistic similarities. Identification of enteric glial cell dysfunction/loss as sufficient to induce necrotic/inflammatory bowel disease may be important to understand the pathogenesis of both NEC and Crohn's disease.

Altered serotonin immunoreactivities in the left colon of patients with colonic inertia

BACKGROUND: Serotonin is an important positive regulator of colonic motility and transit. Its quantity and distribution in the left colon could be abnormal in patients with colonic inertia (CI) and contribute to the disease. AIM: To evaluate serotonin positive cells and immuno-reactivities in the mucosa, submucosa and muscularis propria of the left colon from patients with CI was compared to a control group. PATIENTS AND METHODS: Nineteen patients who underwent subtotal colecotomy for CI were assessed. The control group consisted of 15 patients who underwent left hemicolectomy for colonic cancer; histologically normal tissue specimens were used. Immunohistochemical staining for serotonin was performed. In the mucosa, the average number of serotonin positive cells per microscopic field (200 x ) was determined. The positively stained area (square pixels) in the mucosa, submucosa and muscularis propria per microscopic field (200 x ) was calculated utilizing a computer image analysis program. RESULTS: In the mucosa, both the number of serotonin positive cells and positively stained area were significantly higher in the patient group than in controls (P < 0.05). The difference in serotonin positive area in the submucosa in the CI group compared to the control group was not statistically significant. There was a very significant correlation between the serotonin positive area in the submucosa and muscularis propria in controls (r=0.65, p < 0.01), but not in patients with CI. CONCLUSION: The increased serotonin level in patients with CI may contribute to the disease or be an adaptive response to some other pathology. The lack of a positive correlation in serotonin levels between the submucosa and muscularis propria in CI patients suggests that the coordinated distribution of serotonin may be disrupted in CI.

Results after colectomy for colonic inertia: a sixteen-year experience

BACKGROUND

Colonic inertia (CI) is a disturbance of colonic motility characterized by severe constipation and abdominal pain. This study was conducted to assess the results of total abdominal colectomy (TAC) in the management of CI.

METHODS

A retrospective chart review of 55 patients who underwent TAC for CI was conducted.

RESULTS

Forty-eight patients (87%) were female with an average age of 40; severe constipation existed 2 years prior to surgery. Symptoms included severe constipation (100%) and abdominal pain (84%); diagnostic workup included sitz marker study, anal manometry, and Gastrografin enema. In all cases, sitz marker studies were abnormal and anal manometry was normal. Histologically, no patient had absence of neuroenteric plexuses. Complications included prolonged ileus (24%) and small bowel obstruction (8%). Some 49 patients (89%) had "good" or "excellent" results and 6 patients (11%) had "poor" results. Postoperative stool frequency was 5, 4, and 3 per day at 1, 2, and 12 months, respectively.

CONCLUSIONS

TAC results in resolution of constipation in most patients. We conclude that TAC is effective treatment in patients with CI.

Altered periodic rectal motor activity: a mechanism for slow transit constipation

The pathophysiology of slow transit constipation is poorly understood. Both decreased and increased distal colonic motility have been reported. In healthy humans, a 3 cycles per minute (cpm), periodic rectal motor activity (PRMA) has been described. Our aim was to investigate the characteristics of PRMA and to assess its role in the pathogenesis of constipation. A six-sensor solid-state probe was placed with the tip sensor in the mid-transverse colon, without sedation, and prolonged colonic motility was recorded in nine patients with slow transit constipation (1M, 8F) and in 11 healthy subjects (3M, 8F). Subjects were free to ambulate. We examined the frequency, nocturnal vs. diurnal variation, and characteristics of PRMA, and its relationship to proximal colonic motility. All subjects showed PRMA. The rhythm was similar (2.5-4 cpm) in both groups. However, constipated patients exhibited a greater (P < 0.001) number of PRMA cycles than controls. The duration of each cycle and amplitude of pressure waves during PRMA were also greater (P < 0.05) at night in patients compared with controls. In patients, 40% of PRMA cycles were associated with a proximal colonic motor event compared with 81% in controls (P < 0.02). The area under the curve of all colonic pressure waves and incidence of specialized propagating pressure waves was lower (P < 0.05) in patients during daytime. When compared with controls, constipated patients exhibited reduced daytime colonic pressure waves and a higher frequency of PRMA. Most of the PRMA was unrelated to proximal colonic activity in constipated patients in contrast with findings in control patients. In addition to decreased colonic motility, this excessive and unco-ordinated phasic rectal activity may further impede stool transport and contribute to the pathogenesis of slow transit constipation.

Slow transit constipation in children

Patients with chronic constipation that fails to respond to treatment remain a challenge for paediatricians and surgeons. Ongoing work in our institution suggests that a number of children with intractable symptoms have slow transit constipation, which has only been described recently in paediatrics. Common features of slow transit are: delayed passage of the first meconium stool beyond 24 h of age, symptoms of severe constipation within a year, or treatment-resistant 'encopresis' at 2-3 years, soft stools despite infrequent bowel actions, and delay in colonic transit on a transit study. A proportion of children with slow transit constipation have an abnormality of intestinal innervation associated with the dysfunctional colonic motility, recognized as intestinal neuronal dysplasia (IND). Intestinal neuronal dysplasia type B, the most common variant of IND, is defined on rectal biopsy by hyperplasia of the submucosal plexus. On laparoscopic colon muscle biopsy, many specimens show reduced numbers of excitatory substance P-immunoreactive nerve fibres in the circular muscle. Functional markers of the nerves allow new diagnostic criteria to be developed which may also allow a more rational approach to treatment. The aetiology remains obscure and the optimal management poorly defined, although subtotal colectomy, proximal colostomy or appendicostomy (for antegrade enemas) have been tried. Once the anatomy and physiology of the colon in children with slow colonic transit is better understood, we will have defined not only a new form of constipation, but also will be able to consider new therapies.

Enteric nervous system disorders: genetic and molecular insights for the neurogastroenterologist

The goals of this review are to summarize some of the novel observations on the genetic and molecular basis of enteric nervous system disorders, with particular emphasis on the relevance of these observations to the practicing neurogastroenterologist. In the last two decades, there has been a greater understanding of genetic loci involved in congenital forms of pseudo-obstruction and Hirschsprung's disease; and the contribution of endothelins and nuclear transcription factors to the development of the enteric nervous system. In addition, clarification of the molecules involved in the activation of the peristaltic reflex, the disorders of the interstitial cells of Cajal, the clinical manifestations of mitochondrial cytopathies affecting the gut, and the application of neurotrophic factors for disorders of colonic function have impacted on practical management of patients with gut dysmotility.

Adverse effects of laxatives

Laxatives are among the most commonly used drugs or additives. Most are quite safe when used judiciously, intermittently when possible, and in the absence of contraindications. Bulking agents and nonabsorbable compounds such as lactulose can cause bloating but have very few serious adverse effects except for the allergic reaction to psyllium preparations. Osmotic laxatives containing poorly absorbable ions such as magnesium or phosphate can cause metabolic disturbances, particularly in the presence of renal impairment. However, if taken intermittently, in the absence of conditions such as ileus or bowel obstruction, they have few adverse effects. Polyethylene glycol solutions are emerging as an effective and safe mode of treatment for chronic constipation. Of stimulant laxatives, senna compounds and bisacodyl are the most commonly used. Although there are data to support the neoplastic potential of this class of drugs in in vitro studies, epidemiologic data in humans so far has not established a clear link between these laxatives and colonic neoplasia. The link between stimulant laxatives and structural changes, such as the "cathartic colon" or enteric nerve damage, is not well established either. Danthron compounds should be avoided because of hepatotoxicity.

Neuropathology of paediatric chronic intestinal pseudo-obstruction and related animal models

Chronic intestinal pseudo-obstruction (CIP) in paediatric patients is due to heterogeneous aetiologies that include primary disorders of the enteric nervous system. These conditions are poorly delineated by contemporary diagnostic approaches, in part because the complex nature of the enteric nervous system may shelter significant physiological defects behind subtle or quantitative anatomical changes. Until recently, relatively few experimental animal models existed for paediatric CIP. However, the availability of rodent models, particularly novel mutants created in the last few years by genetic manipulations, has brought unprecedented opportunities to investigate molecular, cellular, physiological, and histological details of enteric neuropathology. Information gleaned from studies of these animals is likely to change diagnostic and therapeutic approaches to paediatric CIP and related conditions.

Gastrointestinal transit and anorectal manometry in children with colonic substance P deficiency

BACKGROUND AND AIMS

Severe intractable constipation in children may be associated with a reduction of substance P (SP)- containing fibers in colonic circular muscle. The aim of this study was to characterize gastrointestinal transit (GIT), anorectal manometry (ARM) and electromyographic (EMG) changes in these children.

METHODS

Seromuscular laparoscopic biopsies of the colon were obtained from 35 children with severe constipation. Immunofluorescent staining for SP and vasoactive intestinal peptide (VIP) were then performed on these specimens. The cohort of patients studied included a SP-deficient group (SPD, n = 25) who had reduced numbers of SP-immunoreactive nerve fibers. The other group consisted of patients with normal staining for both SP and VIP (SPN, n = 10). Gastrointestinal transit studies (gastric emptying, orocecal and colonic transit) suitable for analysis were available for 17 patients (SPD, n = 9 and SPN, n = 8). The colon was divided into segments and radioactivity counts in each segment were expressed as a percentage of the total colonic count at each time point (6, 24, 32 and 48 h). The geometric center (GC), ARM, EMG, clinical and demographic data characteristics of both groups of patients were compared.

RESULTS

There were no differences in demographic data, gastric emptying, orocecal transit or geometric center of transit in the colon between the two patient groups. The ARM and EMG studies suggested that the SPN group have a higher mean threshold volume of balloon distension required to initiate a rectoanal inhibitory reflex, and a higher incidence of anismus; however, this did not reach statistical significance.

CONCLUSIONS

These data suggest a trend that the SPN patients have a greater problem with obstructive defecation and abnormal rectal sensation than those with SPD. We were unable to confirm any defect in colonic transit in the SPD patients compared with the SPN group.

Smooth muscle inclusion bodies in slow transit constipation

Slow transit constipation (STC) is a disorder of intestinal motility of unknown aetiology. Myopathies, including those characterized by the finding of inclusion bodies, have been described in enteric disorders. Amphophilic inclusion bodies have been reported in the muscularis externa of the colon of STC patients. This study formally tested the hypothesis that these represent a primary muscle disorder, specific to STC. In a systematic, blinded, dual observer qualitative and quantitative analysis, colonic and ileal tissue from patients with STC (n=36) were compared with selected control populations: total colonic aganglionosis (n=10), Chagas' disease (n=6), isolated rectal evacuation disorders (n=6), and a control population of a range of ages (n=80). All sections were stained with haematoxylin and eosin and periodic acid Schiff. Further immunostains were used in an attempt to determine inclusion body composition. Round or ovoid (4-22 microm diameter) amphophilic inclusions increased in number in normal subjects with age. Inclusions were more frequent in idiopathic STC than in age-matched controls or rectal evacuation disorders [ileum (33% vs. 9%), ascending (50% vs. 19%, p<0.05), and sigmoid colon (43% vs. 20%)] and were very frequent in the sigmoid (71%) of patients with STC arising after pelvic surgery. The number of inclusions per unit area was significantly higher in patients with STC (p<0.001). Inclusions were found in all Chagas' patients, but not with aganglionosis. It was not possible to determine inclusion body composition, despite the use of a wide range of conventional and immunostains. This study demonstrates that inclusion body myopathy is identifiable in patients with STC and that it may arise secondary to denervation.

Slow transit constipation

Slow transit constipation is a clinical syndrome predominantly affecting young women, characterized by constipation and delayed colonic transit, occasionally associated with pelvic floor dysfunction. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but who are otherwise indistinguishable from irritable bowel syndrome patients at one extreme, to patients with colonic inertia or chronic megacolon at the other extreme. Potential mechanisms for impaired colonic propulsion include fewer colonic HAPCs or a reduced colonic contractile response to a meal. The cause of the syndrome is unclear. The treatment is primarily medical; surgery is reserved for patients with severe disease or colonic inertia. Recognition and treatment of pelvic floor dysfunction is crucial for patients treated medically or surgically. Collaborative studies are necessary to determine the pathophysiology of this disorder and to ascertain the efficacy of novel prokinetic agents.

Surgical treatment of constipation and fecal incontinence

Fecal incontinence is a disabling and distressing condition. Many patients are reluctant to discuss the condition with a physician. A thorough history, good physical examination, and detailed anorectal physiologic investigations can help in the therapeutic decision-making algorithm. Patients with isolated anterior sphincter defects are candidates for overlapping repair. In the presence of unilateral or bilateral pudendal neuropathy, the patient should be counseled preoperatively regarding a [table: see text] lower anticipation of success. If the injury occurred shortly before the planned surgery and neuropathy is present, it may be prudent to wait because neuropathy sometimes can resolve within 6 to 24 months of the injury. Pudendal nerve study may help determine surgical timing. An anterior sphincter defect combined with a rectovaginal fistula can be approached by overlapping sphincter repair and a concomitant transanal advancement flap. Patients who had undergone multiple such procedures may benefit from concomitant fecal diversion at the time of repeat sphincter repair. Patients with global or multifocal sphincter injury may be candidates for a neosphincter procedure. The stimulated graciloplasty and artificial bowel sphincter are reasonable options. In the absence of the availability of these techniques or because of financial constraints, consideration could be given to bilateral gluteoplasty or unilateral or bilateral nonstimulated graciloplasty. The postanal repair still serves a role in patients with isolated decreased resting pressures with or without neuropathy or external sphincter injury with minimal degrees of incontinence. Biofeedback and the Procon device may play a role in these patients. Lastly, fecal diversion must be considered as a means of improving the quality of life because the patient can participate in the activities of daily living without the fear of fecal incontinence.

Abnormal contractile properties of rectal smooth muscle in chronic ulcerative colitis

BACKGROUND

Patients with ulcerative colitis have abnormal rectal motility.

AIM

To compare the contractile properties of rectal smooth muscle from patients with ulcerative colitis and controls.

METHODS

Rectal smooth muscle strips from patients undergoing resection for ulcerative colitis or cancer (control) were mounted in an organ bath. The effects of carbachol (receptor-mediated) and potassium (causes membrane depolarization) were studied. Acetylcholinesterase histochemistry was performed and nerve counts compared.

RESULTS

Ulcerative colitis (n=41) and control (n=34) strips contracted in response to potassium and carbachol. Mean (S.E. M.) maximum response to potassium in the control and ulcerative colitis groups was 1.07 (0.06) g/mg and 1.02 (0.09) g/mg tissue, respectively (P=N.S.). EC50s (concentrations required to give 50% of maximal response) were 75 (1) mM and 73 (1) mM, respectively (P=N.S. ). Although maximum responses to carbachol were similar, 2.12 (0.12) g/mg and 1.95 (0.12) g/mg tissue (P=N.S.), ulcerative colitis strips exhibited an increased sensitivity to carbachol, EC50s: 5.05 x 10-6 (0.55 x 10-6) M vs. 8.36 x 10-6 (0.88 x 10-6) M, P=0.002). There was no significant difference in nerve counts between the tissues, as assessed by staining for acetylcholinesterase.

CONCLUSIONS

Ulcerative colitis tissue has an increased sensitivity to carbachol and this is not due to denervation; it may result from increased calcium release from intracellular stores since contraction due to membrane depolarization is not altered. Modulation of this pathway could potentially be used to alter rectal motility in patients with ulcerative colitis.

Effect of colectomy on gastric emptying in idiopathic slow-transit constipation

INTRODUCTION

Gastric emptying is delayed in patients with idiopathic slow-transit constipation (ISTC). Gastric emptying was measured before and after colectomy and ileorectal anastomosis in patients with ISTC to determine whether the abnormality persists after operation.

METHODS

Twelve patients undergoing colectomy for severe ISTC had solid-phase gastric emptying measured after an overnight fast. All 12 had an uncomplicated subtotal colectomy and ileorectal anastomosis; 11 had an excellent functional outcome. In ten of these patients gastric emptying was repeated within 3 months of operation. Seven patients (including the remaining two) had the study performed at 1 year.

RESULTS

All 12 patients had severely delayed gastric emptying before operation. Gastric emptying remained delayed in the ten patients who underwent an early postoperative gastric emptying study. Six of seven patients assessed at 1 year had improved gastric emptying, of whom four had returned to normal. Functional outcome did not relate to gastric emptying.

CONCLUSION

Patients with ISTC have delayed gastric emptying. In some patients this returns to normal after colectomy, but is persistent in others. This may have implications for our understanding of ISTC.

Differential effects of maturation on nicotinic- and muscarinic receptor-induced ion secretion in guinea pig distal colon

The incidence of constipation increases with age. This has been linked to age-related changes in the structure and function of myenteric neurons regulating intestinal motility; however, the role of submucous neurons is unknown. The aim of this study was to determine the effect of maturation on cholinergic receptor-induced ion secretion in guinea pig colon. Changes in the short-circuit current (Isc) and tissue conductance were monitored in muscle-stripped colonic segments from young (3-4-month-old) and mature (12-15-month-old) male guinea pigs. Thirty-one percent of colonic segments from young guinea pigs exhibited ongoing neural activity, which was absent in mature animals. Baseline Isc was significantly higher only in young guinea pig tissues with ongoing activity. Tissue conductance was similar in all tissues. Electrical field stimulation caused a biphasic increase in the Isc. At 15 V/10 Hz, only Peak 1 was attenuated, whereas both peaks were reduced in mature guinea pigs at 10 V/5Hz. 1,1, dimethyl-4-phenyl-piperazinium(DMPP)-induced ion secretion was blunted in mature guinea pigs. Atropine reduced the 1,1, dimethyl-4-phenyl-piperazinium response only in young guinea pigs. Carbachol-induced ion secretion was similar in tissues from both age groups. In conclusion, nicotinic receptor-induced secretion mediated by both cholinergic and noncholinergic secretomotor neurons was blunted; however, epithelial muscarinic receptor activity was unaltered during maturation.

Enterochromaffin and serotonin cells are abnormal for patients with colonic inertia

PURPOSE

In recent studies, serotonin and several gut peptides have been shown to serve as regulators of colonic transit. Thus, the distribution, density, and intensity of cells secreting serotonin or certain gut peptides could be abnormal in patients with colonic inertia. The aim of this study was to evaluate the distribution, density, and staining intensity of enterochromaffin and serotonin cells in the colonic mucosa of patients with colonic inertia compared with a control group.

METHODS

Between 1993 and 1998 tissue blocks from the right and left side of the colon were obtained in 19 consecutive patients (18 females; mean age, 43.7 +/- 11.5 years) who underwent subtotal colectomy for colonic inertia. The control group consisted of colonoscopic biopsies from the right and left colon of 15 patients (all females; mean age, 52.7 +/- 16.5 years) for indications other then constipation, inflammatory bowel diseases, or carcinoma. Immunocytochemical staining of enterochromaffin and serotonin cells were performed on 4 microm tissue sections with the primary rabbit antibody against chromogranin A or serotonin, and the biotinylated secondary antibody and enzyme-labeled-streptavidin. The average cell number per microscopic field (x200) was calculated and the proportion of cells with various staining distribution was expressed as the percentage of the entire positive cell population as low, moderate, and high intensity. Student's t-test and chi-squared test were used for statistical analysis, with significance level set at P < 0.05.

RESULTS

The quantity of both enterochromaffin cells (16.8 +/- 10.2) and serotonin cells (12.1 +/- 6.4) in the mucosa of the left colon in patients with colonic inertia was significantly higher when compared with the right side of the colon (enterochromaffin cells, 9.4 +/- 6.0; serotonin cells, 7.8 +/- 3.6; P < 0.01). The percentage of both types of cells with low staining intensity was increased, whereas the cells with high and moderate staining intensity were decreased (P < 0.01) in the left colon as compared with the right. The number of enterochromaffin cells in left-sided colonic mucosa was significantly higher in the colonic inertia group than in the control group (16.8 +/- 10.1 vs. 10.4 +/- 6.0; P < 0.05). Moreover, the numbers of serotonin cells in both the right and left colon was also significantly higher in the colonic inertia group than in the control group (right, 7.8 +/- 3.6 vs. 4.1 +/- 2.4; left, 12.1 +/- 6.4 vs. 5.8 +/- 3.7; P < 0.01). In both sides of the colon, the percentage of enterochromaffin and serotonin cells with low staining was significantly higher, whereas percentage of those cells with high or moderate staining was significantly lower in the colonic inertia group than in the control group. In the colonic inertia group there was a significantly positive correlation between numbers of enterochromaffin and serotonin cells (right side, P < 0.01; left side, P < 0.05).

CONCLUSION

In patients with colonic inertia, the number of both enterochromaffin and serotonin cells are significantly increased in the colonic mucosa, especially in the left colon. As indicated by staining distribution, enterochromaffin and serotonin cells contain significantly less hormone than do the same cells in the control group.

Idiopathic slow-transit constipation is not associated with mutations of the RET proto-oncogene or GDNF

PURPOSE

Idiopathic slow-transit constipation is a severe disorder of unknown cause. The onset in early childhood and history of constipation or Hirschsprung's disease in close family relatives suggest that slow-transit constipation could have a genetic basis. Several germline mutations have been described in Hirschsprung's disease, including mutations of RET and the gene encoding its ligand glial cell-derived neurotrophic factor. The aim of this study was to screen a panel of 16 cases of familial idiopathic slow-transit constipation, including 4 families in which there were relatives with Hirschsprung's disease, for RET and glial cell-derived neurotrophic factor mutations previously identified in Hirschsprung's disease.

METHODS

Genomic DNA from 16 patients with slow-transit constipation and four relatives with Hirschsprung's disease was analyzed using single strand and heteroduplex conformation polymorphism analysis at two conditions and by direct DNA sequencing using the fluorescent dideoxy terminator method.

RESULTS

Although common sequence polymorphisms were demonstrated with a frequency comparable with published data, no published or new mutation was seen in any of the exons of RET or glial cell-derived neurotrophic factor.

CONCLUSIONS

Mutation of RET or glial cell-derived neurotrophic factor is not a frequent cause of idiopathic slow-transit constipation.

Interstitial cells of Cajal in slow transit constipation and megabowel

OBJECTIVE

Disordered gut motor activity is a feature of patients with chronic idiopathic constipation. Interstitial cells of Cajal (ICC) are thought to modulate gut motility. The aim of this study was to test the hypothesis that there is an abnormality of the density of distribution of ICC in slow transit constipation and megabowel.

PATIENTS AND METHODS

ICC were identified by immunohistochemistry using an anti-c-kit antibody. Six patients (slow transit constipation n=3; megabowel n=3) were compared with normal controls. The density of distribution of ICC was assessed in the longitudinal and circular muscle layers, and in the intermuscular plane of the colon. Statistical analysis was performed using Fisher's exact test and χ(2) test.

RESULTS

No consistent pattern of difference in the density of ICC could be identified between the constipated and control groups.

CONCLUSION

The density of ICC in the constipated patients was not significantly different from normal colon. The results in these patients suggest that if ICC have a role in the causation of slow transit idiopathic constipation or megabowel then an abnormality of function rather than distribution is implicated.

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

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

Opioid Type and Other Clinical Predictors of Laxative Dose in Advanced Cancer Patients: A Retrospective Study

BACKGROUND

Constipation is a frequent and underdiagnosed complication in patients with advanced cancer. Constipation in this population is multifactorial, but the use of opioids is one of the main causes. The purpose of this retrospective study was to establish the association between opioid type and laxative dose, as well as the contribution of other clinical factors in advanced cancer patients admitted to a palliative care unit.

METHODS

The records of consecutive patients admitted to the Acute Palliative Care Unit at the Grey Nuns Hospital between December 1995 and January 1997 were reviewed. Criteria of eligibility were the presence of cancer pain treated by opioids (oral and subcutaneous morphine and hydromorphone, oral methadone), oral laxative treatment capable of achieving at least one bowel movement every 3 days, and the absence of bowel obstruction or colostomy. During period(s) of stable analgesic doses, the charts were reviewed for demographic and clinical characteristics, average number of bowel movements, daily laxative doses, doses and type of opioid, laxative/opioid dose ratio (LOR) (calculated by dividing the total laxative dose by the total opioid dose), functional and cognitive status, food intake, and level of calcium, albumin, and potassium.

RESULTS

Forty-nine evaluable patients were identified. The LOR in patients receiving oral opioids was 0.15 +/- 0.19 vs. 0.18 +/- 0.17 in patients on parenteral opioids (p > 0.2). The LOR in patients receiving methadone was 0.025 +/- 0.027 as compared to 0.24 +/- 0.23 in patients receiving morphine and 0.17 +/- 0.13 in patients on hydromorphone (p < 0.0001). We found a strong association between LOR and abdominal involvement (p < 0.0006), opioid type (p < 0.0001), age (p < 0.0001), and female gender (p < 0.034). There were no significant correlation between LOR and functional status, cognitive status, food intake, and level of calcium or potassium.

CONCLUSION

We conclude that laxative dose needs to be titrated on an individualized basis. The LOR is lower in patients receiving methadone and in those of male gender, younger age, and absence of abdominal involvement.

Rectal pacing: pacing parameters required for rectal evacuation of normal and constipated subjects

BACKGROUND AND PURPOSE

Our previous studies have demonstrated that rectal electric waves start at the rectosigmoid junction (RSJ) and spread caudad along the rectum. A rectosigmoid pacemaker was postulated to exist at the RSJ. We also demonstrated that electric waves in rectal inertia are so scarce that a "silent" electrorectogram is recorded; the myoelectric activity in such cases was stimulated by an artificial pacemaker placed at the RSJ. For this article we investigated the pacing parameters necessary for rectal evacuation in rectal inertia patients.

METHODS

The study comprised 24 patients with rectal inertia divided into two groups: study group (10 women, 6 men; mean age, 38.9 +/- 10.6 years) and control group (6 women, 2 men; mean age, 36.3 +/- 9.8 years). The main complaint was infrequent defecation and straining at stools. Eight healthy volunteers (6 women, 2 men; mean age, 37.2 +/- 9.4 years) with normal stool frequency were included in the study. Through a sigmoidoscope, an electrode was hooked to the RSJ (stimulating) and two electrodes were hooked to the rectal mucosa (recording). Rectal electric activity was recorded before (basal activity) and during electric stimulation of the RSJ electrode with an electrical stimulator delivering constant electric current of 5-mA amplitude and 200-ms pulse width.

RESULTS

In the healthy volunteers, rectal pacing effected increases in frequency, amplitude, and velocity from a mean of 2.3 +/- 0.9 to 6.2 +/- 1.8 cycles/min (P < 0.01), 1.2 +/- 0.6 to 1.7 +/- 0.8 mV (P < 0.05), and 4.1 +/- 1. 2 to 6.3 +/- 1.7 cm/s (P < 0.05), respectively. No waves were recorded from rectal inertia patients at rest. Rectal pacing of the study group showed pacesetter potentials with a mean frequency of 2. 1 +/- 1.2 cycles/min, amplitude of 0.9 +/- 0.1 mV, and velocity of 3. 3 +/- 1.6 ms. The control group, in whom the pacemaker was not activated, showed no electric activity.

CONCLUSIONS

Rectal pacing succeeded in producing myoelectric activity in patients with rectal inertia. It is therefore suggested that this method be applied for rectal evacuation in patients with inertia constipation.

Decreased interstitial cell of cajal volume in patients with slow-transit constipation

BACKGROUND & AIMS

The cause of slow-transit constipation is incompletely understood. Recent observations suggest a central role for interstitial cells of Cajal in the control of intestinal motility. The aim of this study was to determine the volume of interstitial cells of Cajal in the normal sigmoid colon and in the sigmoid colon from patients with slow transit constipation.

METHODS

Sigmoid colonic samples were stained with antibodies to protein gene product 9.5, c-Kit, and alpha-smooth muscle actin. Three-dimensional reconstruction of regions of interest was performed using consecutive images collected on a laser scanning confocal microscope and ANALYZE software.

RESULTS

Volume of interstitial cells of Cajal was significantly decreased in all layers of sigmoid colonic specimens from patients with slow-transit constipation compared with normal controls. Neuronal structures within the colonic circular smooth muscle layer were also decreased.

CONCLUSIONS

A decrease in the volume of interstitial cells of Cajal may play an important role in the pathophysiology of slow-transit constipation.

Operative Management of Severe Constipation

This report investigates the concept that severe constipation requiring major abdominal surgery may result from one of three common causes: 1) colonic inertia, 2) pelvic hiatal hernia, or 3) both colonic inertia and pelvic hernia. This study evaluates the symptoms, anatomy and outcome in 201 patients with severe surgical constipation treated by a single surgeon. In 2042 patients with constipation referred to one colon and rectal surgeon, 211 major abdominal surgical procedures were performed on 201 patients for severe constipation between 1989 and 1999. There were 187 women and 14 men. Mean age was 49 years (range, 9–84). Five high-risk patients had ileostomy; 196 had major colonic surgery for anatomic or physiologic causes of constipation, excluding malignancy, diverticular disease, and inflammatory bowel disease. Pelvic hiatal hernia was defined as the herniation of bowel through the hiatus of the pelvic diaphragm seen on pelvic videofluoroscopy or physical examination. Of these 196 patients, 44 per cent had pelvic hiatal hernia repair (PHHR), 27 per cent had total abdominal colectomy and ileorectal anastomosis for colonic inertia, and 29 per cent had surgery for both colonic inertia and pelvic hiatal hernia. Of the 144 patients undergoing PHHR, 95 had Gore-Tex® patch (W. L. Gore and Associates, Inc., Phoenix, AZ) sacral colpopexy. PHHR for pelvic hiatal hernia without colonic inertia included sigmoid resection, rectopexy, and Gore-Tex patch sacral colpopexy. Mean duration of follow-up was 20 months. Symptoms noted preoperatively included abdominal pain (84%), straining at stool (90%), incomplete rectal emptying (85%), painful bowel movements (74%), pelvic pain (69%), vaginal bulge (55%), digital assistance with evacuation (35%), and incontinence of stool (38%). Outcome assessed by symptom relief was successful in 89.1 per cent of patients. 8.6 per cent of patient conditions were unchanged, and 2.3 per cent were unsatisfied with the outcome. There were no postoperative deaths. The complication rate was 6.1 per cent (small bowel obstruction, 7; anastomotic leak, 2; ureteral stenosis, 2; and patch erosion, 1). In our experience, severe surgical constipation can be due to colonic inertia, pelvic hiatal hernia, or both. Careful preoperative evaluation identifies these disorders, and surgical therapy aimed at correction of anatomic and physiologic defects results in high patient satisfaction and improvement in bowel function.

Outcome of colectomy for slow transit constipation

OBJECTIVE

To review the outcome data for colectomy performed for patients with slow transit constipation (STC).

BACKGROUND

The outcome of surgical intervention in patients with STC is unpredictable. This may be a consequence of the lack of effectiveness of such interventions or may reflect heterogeneity within this group of patients.

METHODS

The authors reviewed the data of all series in the English language that document the outcome of colectomy in > or = 10 patients in the treatment of STC.

RESULTS

Thirty-two series fulfilled the entry criteria. There was widespread variability in patient satisfaction rates after colectomy (39% to 100%), reflecting large differences in the incidence of postoperative complications and in long-term functional results. Outcome was dependent on several clinical and pathophysiologic findings and on the type of study, the population studied, and the surgical procedure used.

CONCLUSIONS

It may be possible to predict outcome on the basis of preoperative clinical and pathophysiologic findings. This review suggests a rationale for the selection of patients for colectomy.

Colonic motility in man: features in normal subjects and in patients with chronic idiopathic constipation

The human colon is still a relatively unknown viscus, especially concerning its motor activity. However, in recent years, techniques have been perfected that allow a better understanding of colonic motility, especially through prolonged recording periods. In this way, it has been demonstrated that the viscus contracts according to a circadian trend, is responsive to physiological stimuli (meals, sleep), and features high amplitude, propulsive contractions that are part of the complex dynamic of the defecatory process. These physiological properties and their alterations in patients with chronic idiopathic constipation are reviewed in this article.