Steroid hormone abnormalities in women with severe idiopathic constipation

Tryptophan Metabolism in Postmenopausal Women with Functional Constipation

Constipation belongs to conditions commonly reported by postmenopausal women, but the mechanism behind this association is not fully known. The aim of the present study was to determine the relationship between some metabolites of tryptophan (TRP) and the occurrence and severity of abdominal symptoms (Rome IV) in postmenopausal women with functional constipation (FC, n = 40) as compared with age-adjusted postmenopausal women without FC. All women controlled their TRP intake in their daily diet. Urinary levels of TRP and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), and 3-indoxyl sulfate (indican, 3-IS), were determined by liquid chromatography/tandem mass spectrometry. Dysbiosis was assessed by a hydrogen-methane breath test. Women with FC consumed less TRP and had a lower urinary level of 5-HIAA, but higher levels of KYN and 3-IS compared with controls. The severity of symptoms showed a negative correlation with the 5-HIAA level, and a positive correlation with the 3-IS level. In conclusion, changes in TRP metabolism may contribute to FC in postmenopausal women, and dysbiosis may underlie this contribution.

HPA axis activity across the menstrual cycle - a systematic review and meta-analysis of longitudinal studies

Differential HPA axis function has been proposed to underlie sex-differences in mental disorders; however, the impact of fluctuating sex hormones across the menstrual cycle on HPA axis activity is still unclear. This meta-analysis investigated basal cortisol concentrations as a marker for HPA axis activity across the menstrual cycle. Through a systematic literature search of five databases, 121 longitudinal studies were included, summarizing data of 2641 healthy, cycling participants between the ages of 18 and 45. The meta-analysis showed higher cortisol concentrations in the follicular vs. luteal phase (d_SMC = 0.12, p =.004, [0.04 - 0.20]). Comparisons between more precise cycle phases were mostly insignificant, aside from higher concentrations in the menstrual vs. premenstrual phase (d_SMC = 0.17, [0.02 - 0.33], p =.03). In all included studies, nine samples used established cortisol parameters to indicate HPA axis function, specifically diurnal profiles (k = 4) and the cortisol awakening response (CAR) (k = 5). Therefore, the meta-analysis highlights the need for more rigorous investigation of HPA axis activity and menstrual cycle phase.

Diminished androgen levels are linked to irritable bowel syndrome and cause bowel dysfunction in mice

Functional gastrointestinal disorders (FGIDs) have prominent sex differences in incidence, symptoms, and treatment response that are not well understood. Androgens are steroid hormones present at much higher levels in males than females and could be involved in these differences. In adults with irritable bowel syndrome (IBS), a FGID that affects 5-10% of the population worldwide, we found that free testosterone levels were lower than those in healthy controls and inversely correlated with symptom severity. To determine how this diminished androgen signaling could contribute to bowel dysfunction, we depleted gonadal androgens in adult mice and found that this caused a profound deficit in gastrointestinal transit. Restoring a single androgen hormone was sufficient to rescue this deficit, suggesting that circulating androgens are essential for normal bowel motility in vivo. To determine the site of action, we probed androgen receptor expression in the intestine and discovered, unexpectedly, that a large subset of enteric neurons became androgen-responsive upon puberty. Androgen signaling to these neurons was required for normal colonic motility in adult mice. Taken together, these observations establish a role for gonadal androgens in the neural regulation of bowel function and link altered androgen levels with a common digestive disorder.

Constipation and diarrhea during the menopause transition and early postmenopause: observations from the Seattle Midlife Women's Health Study

OBJECTIVE

To assess the relationship of constipation and diarrhea severity during the menopause transition (MT) with age, MT stage, reproductive biomarkers, stress-related biomarkers, and stress-related perceptions.

METHODS

From 1990 to 1992, women aged 35 to 55 years were recruited from the greater Seattle area; 291 of them consented to ongoing (1990-2013) annual data collection by daily menstrual calendar, health diary, and annual health questionnaire. A subset (n = 131) provided a first morning voided urine specimen (1997-2013). These were assayed for levels of E1G, follicle-stimulating hormone, testosterone, cortisol, norepinephrine, and epinephrine. Mixed-effects modeling was used to identify how changes in constipation and diarrhea severity over time related to age, MT stage, reproductive biomarkers, stress-related biomarkers, and stress-related perceptions.

RESULTS

In a univariate model, age, late reproductive (LR) stage, tension, and anxiety were all significantly and positively related to constipation severity, whereas cortisol was significantly and negatively associated. In a multivariate model, only tension and cortisol remained significant predictors of constipation severity (P < 0.05). In a univariate model, age, LR stage, and estrone glucuronide were significantly and negatively associated with diarrhea severity, whereas tension, anxiety, and perceived stress were significantly and positively related. In a multivariate model, only tension and age remained significant predictors of diarrhea severity.

CONCLUSIONS

Key reproductive hormones do not play a significant role in constipation or diarrhea severity in the MT. In contrast, stress perception, tension, anxiety, and cortisol do. These factors should be evaluated in further research involving constipation and diarrhea.

Chronic severe constipation: current pathophysiological aspects, new diagnostic approaches, and therapeutic options

Chronic constipation is a considerable problem because it significantly affects the quality of a patient's life. Constipation can be diagnosed at every age and is more frequent in women and among the elderly. In epidemiological studies, its incidence is estimated at 2-27% in the general population. Chronic constipation may be primary or secondary. However, primary constipation (functional or idiopathic) can be classified into normal transit constipation, slow transit constipation, and pelvic outlet obstruction. In this review we make an attempt to present the current pathophysiological aspects and new therapeutic options for chronic idiopathic constipation, particularly highlighting the value of patient assessment for accurate diagnosis of the cause of the problem, thus helping in the choice of appropriate treatment.

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.

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.

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.

Is the DHEAS/cortisol ratio a potential filter for non-operable constipated cases?

Constipation is a significant manifestation of a number of psychological disorders. Published papers recommend using self-assessment questionnaires for discriminating psychological from non-psychological constipated patients before operating on them but reports from major surveys revealed that general practitioners failed to diagnose 70% of depressed patients using self-assessment questionnaires. Lower circulating concentrations of progesterone, 17-hydroxyprogesterone, cortisol, testosterone, androstenedione, and dehydroepiandrostenedione sulfate (DHEAS) during the follicular phase in constipated young women compared with respective controls were found during the follicular phase of the menstrual cycles. During the luteal phase of the cycle, reductions were identified in estriol, cortisol and testosterone in the constipated group. Likewise, circulating concentrations of DHEAS were found to be lower in depressed patients than comparable healthy controls. DHEAS/cortisol ratios in morning serum and salivary samples were lower than those retrieved during other times of the day in depressed patients. The idea of recognizing major depression in constipated patients by measuring DHEAS/cortisol ratios in saliva and serum may be plausible but this possibility needs to be confirmed in well-designed studies.

Overexpression of progesterone receptor B increases sensitivity of human colon muscle cells to progesterone

Colon muscle strips and cells from female patients with slow-transit constipation (STC) exhibit impaired motility, signal transduction abnormalities characterized by downregulation of Gq/11 and upregulation of Gs proteins, decreased cyclooxygenase (COX)-1 and thromboxane (Tx)B2 levels, increased COX-2 and PGE2 levels, and overexpression of progesterone receptors (PGR). Progesterone (P4) treatment of normal cells reproduced these motility and signal transduction abnormalities. The purpose of the study was to examine whether overexpression of PGR-B reproduces these abnormalities by rendering the cells more sensitive to physiological concentrations of P4. Cultured human colon muscle was transfected with a plasmid DNA expressing PGR-B. The mRNAs of PGR, COX-1, COX-2, and Gq/11 were determined by quantitative real-time PCR. Their protein expression was determined by Western blot, and prostaglandins were measured by radioimmunoassay. Cultured muscle cells maintained their phenotypic features determined with myosin light chain (MLC) and h-caldesmon antibodies. Control and transfected muscle cells responded to 10(-6) M P4. In contrast, muscle cells transfected with PGR-B responded to lower P4 concentration (10(-7) M). This P4 concentration reduced MLC phosphorylation induced by CCK-8 (10(-8) M), downregulated Gq/11, and decreased COX-1 and TxB2 levels. It upregulated Gs proteins. It also increased COX-2 and PGE2 levels. We conclude that overexpression of PGR-B renders the cells more sensitive to physiological concentrations of P4. These results are consistent with the hypothesis that overexpression of PGR-B contributes to the motility and signal transduction abnormalities observed in female patients with STC and normal serum levels of P4.

Constipation and pregnancy

Constipation is a common symptom during pregnancy. The majority of cases are simple constipation that occurs due to a combination of hormonal and mechanical factors affecting normal GI function. However, a number of women suffer from constipation prior to conception and find their symptoms worsen during pregnancy. Patients with simple constipation can usually be treated by explanation, reassurance and advice. Medications are best avoided but if necessary should be taken under supervision using best available evidence. It is important that all patients be evaluated by detailed history, physical examination and basic investigations to outrule GI pathology that may be present in a small number of cases. Those whose symptoms predated their pregnancy should be fully evaluated after the puerperium.

Abnormalities of prostaglandins and cyclooxygenase enzymes in female patients with slow-transit constipation

BACKGROUND AND AIMS

Chronic constipation due to slow transit (STC) is more common in female than in male patients. We have previously shown that these gender differences may be due to over expression of progesterone (PG) receptors that alter G protein patterns. We sought to elucidate the mechanisms responsible for the impaired basal colonic motility in female patients with STC.

METHODS

Muscle tissues from females with STC and controls with adeno-carcinoma of the colon were studied. Prostaglandins were determined by immunoassay, COX enzymes by Western blot and COX enzymes and progesterone receptors mRNA by RT-PCR.

RESULTS

STC patients had impaired colonic motility index, lower TxA(2) and PGF(2) and higher PGE(2) levels than controls. STC had lower COX-1 protein and mRNA levels and higher COX-2 protein and mRNA levels than controls. These abnormalities were reproduced in normal colonic muscle cells treated with PG for 6 h. STC patients had higher PG receptor protein expression and mRNA levels than controls suggesting over expression of these receptors.

CONCLUSIONS

These findings suggest that the impaired motility index of STC is due to abnormal levels of prostaglandin and COX enzymes, probably caused by an over expression of PG receptors that make muscle cells more sensitive to circulating levels of PG.

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

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

Effects of female steroid hormones on A-type K+ currents in murine colon

Idiopathic constipation is higher in women of reproductive age than postmenopausal women or men, suggesting that female steroid hormones influence gastrointestinal motility. How female hormones affect motility is unclear. Colonic motility is regulated by ion channels in colonic myocytes. Voltage-dependent K(+) channels serve to set the excitability of colonic muscles. We investigated regulation of Kv 4.3 channel expression in response to acute or chronic changes in female hormones. Patch clamp experiments and quantitative PCR were used to compare outward currents and transcript expression in colonic myocytes from male, non-pregnant, pregnant and ovariectomized mice. Groups of ovariectomized mice received injections of oestrogen or progesterone to investigate the effects of hormone replacement. The capacitance of colonic myocytes from non-pregnant females was larger than in males. Net outward current density in male and ovariectomized mice was higher than in non-pregnant females and oestrogen-treated ovariectomized mice. Current densities in late pregnancy were lower than in female controls. Progesterone had no effect on outward currents. A-type currents were decreased in non-pregnant females compared with ovariectomized mice, and were further decreased by pregnancy or oestrogen replacement. Kv 4.3 transcripts did not differ significantly between groups; however, expression of the potassium channel interacting protein KChIP1 was elevated in ovariectomized mice compared with female controls and oestrogen-treated ovariectomized mice. Delayed rectifier currents were not affected by oestrogen. In the mouse colon, oestrogen suppresses A-type currents, which are important for regulating excitability. These observations suggest a possible link between female hormones and altered colonic motility associated with menses, pregnancy and menopause.

Role of progesterone signaling in the regulation of G-protein levels in female chronic constipation

BACKGROUND & AIMS

Chronic constipation caused by slow transit is common in women with an F/M ratio of 9:1. The cause and mechanisms responsible for this syndrome are unknown. Progesterone has been suggested as a possible contributing factor. Our aim was to investigate the site and mechanisms responsible for this colonic motility disorder.

METHODS

Seven women with intractable constipation and slow transit time underwent colectomy and 6 women who underwent a left colectomy for adenocarcinoma (controls) were studied. Dissociated colonic circular muscle cells were obtained by enzymatic digestion. Changes in G-protein levels were measured by Western blot. The messenger RNA (mRNA) expression of Galpha q and progesterone receptors was determined by reverse-transcription polymerase chain reaction and Northern blot.

RESULTS

Muscle cells from patients with chronic constipation exhibited impaired contraction in response to receptor-G-protein-dependent agonists (cholecystokinin [CCK], acetylcholine) and in response to the direct G-protein activator guanosine 5'-O-(3-thiophosphate). Contraction was normal with receptor-G-protein-independent agonists (diacylglycerol and KCl). Western blot showed down-regulation of Galpha q/11 and up-regulation of Galpha s proteins in patients with chronic constipation. The mRNA expression of Galpha q was lower and the progesterone receptors were overexpressed in patients with chronic constipation compared with controls. These abnormalities were reproduced in vitro by pretreatment of normal colonic muscle cells with progesterone for 4 hours.

CONCLUSIONS

Slow transit chronic constipation in women may be caused by down-regulation of contractile G proteins and up-regulation of inhibitory G proteins, probably caused by overexpression of progesterone receptors.

Myths and misconceptions about chronic constipation

There are many strongly held beliefs about constipation that are not evidence based. The purpose of this review is to address these beliefs concerning various aspects of constipation. There is no evidence to support the theory that diseases may arise via "autointoxication," whereby poisonous substances from stools within the colon are absorbed. Dolichocolon, defined as an elongated colon, should not be seen as a cause of constipation. The role of sex hormones altering gut function during the menstrual cycle appears to be minimal. During pregnancy they may play a role in slowing gut transit. Hypothyroidism can cause constipation, but among patients presenting with constipation, hypothyroidism is rare. A diet poor in fiber should not be assumed to be the cause of chronic constipation. Some patients may be helped by a fiber-rich diet but many patients with more severe constipation get worse symptoms when increasing dietary fiber intake. There is no evidence that constipation can successfully be treated by increasing fluid intake unless there is evidence of dehydration. In the elderly constipation may correlate with decreased physical activity, but many cofactors are likely to play a role. Intervention programs to increase physical activity as part of a broad rehabilitation program may help. It is unlikely that stimulant laxatives at recommended doses are harmful to the colon. A proportion of patients with chronic constipation is dependent of laxatives to achieve satisfactory bowel function, but this is not the result of prior laxative intake. Tolerance to stimulant laxatives is uncommon. There is no indication for the occurrence of "rebound constipation" after stopping laxative intake. While laxatives may be misused, there is no potential for addiction.

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.

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.

The irritable bowel syndrome during pregnancy

The irritable bowel syndrome (IBS) is characterized by altered bowel habits and abdominal discomfort in the absence of organic disease. No markers exist for IBS, and the definition of IBS is based on the presence of specific symptoms. The Rome II criteria for defining IBS include abdominal pain or discomfort for 12 weeks or longer, which need not be continuous, over the past 12 months plus two of the following: (1) relief of discomfort with defecation; (2) association of discomfort with altered stool frequency; and (3) association of discomfort with altered stool form. Nine percent to 22% of the population report symptoms consistent with IBS. IBS is the most prevalent digestive disease, representing 12% of visits to primary care physicians and 28% of referrals to gastroenterologists.

Prucalopride, a systemic enterokinetic, for the treatment of constipation

BACKGROUND

Laxatives are frequently ineffective in treating constipation. An alternative therapeutic approach is to target serotonin-4 receptors, which are involved in initiating peristalsis.

AIM

In a double-blind, placebo-controlled trial, to assess the efficacy and safety of a systemically active serotonin-4 agonist, prucalopride.

METHODS

Seventy-four women with constipation were stratified into slow or normal transit groups, and each group was randomized to receive either placebo or 1 mg prucalopride daily for 4 weeks. A bowel function diary was maintained. Whole-gut and orocaecal transit, visceral sensitivity, quality of life and psychological state were assessed before and after treatment.

RESULTS

Prucalopride, not placebo, increased spontaneous stool frequency (P=0.008) and reduced time to first stool (P < 0.001). Prucalopride reduced the number of retained markers in all patients compared to placebo (P=0.004). Prucalopride reduced the mean number of retained markers in slow transit (P=0.069), but did not alter the marker count in normal transit (P=0.86). Orocaecal transit was accelerated by prucalopride, not placebo (P=0.004). Prucalopride, notplacebo, increased rectal sensitivity to distension (urge volume, P=0.01) and electrical stimulation (P=0.001). Prucalopride significantly improved several domains of the Short Form Health Status Survey and the disease-specific quality of life. Adverse effects were similar for prucalopride and placebo.

CONCLUSIONS

Prucalopride improves symptoms, upper gut transit and gut sensitivity in constipated patients with both slow and normal transit. It improves transit in patients with slow transit. These changes are associated with improved well-being.

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.

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.

Problems and challenges in the design of irritable bowel syndrome clinical trials: experience from published trials

The last two decades have seen many studies that are of inadequate design and power. This report focuses on what we have learned from the 25 randomized, controlled studies that included at least 30 patients during the period 1976-1998. The most important finding has been that the median placebo response was 47% (range, 0-84%), which is approximately three times the size of the difference between placebo and drug response, median 16% (range, -17-64%). This tells us the importance of reassurance and the powerful nonspecific therapeutic effects of entering patients into clinical trials in irritable bowel syndrome (IBS). Patients should be stratified according to the dominant symptoms that are relevant to the drug's intended effect. A randomized, double-blind, controlled, parallel group study appears the most robust design. Minimizing the placebo response reduces the numbers needed to detect a significant difference. The optimum length of trial is probably >3 months, because the placebo effect takes approximately 12 weeks to start to recede. Dose titration should maximize the chance of detecting a benefit.

Sensory and autonomic neuropathy in patients with idiopathic slow-transit constipation

BACKGROUND

Slow-transit constipation (STC) is a severe disorder of unknown aetiology, which may result from an autonomic or sensory neuropathy. This study aimed to investigate patients with STC for the presence of neural dysfunction, and relate the findings to other factors, including any familial associations.

METHODS

Thirty-three patients with STC were studied using standard neurophysiological tests and a range of quantitative sensory and autonomic tests. The findings were compared with those of 20 matched control subjects and nine diabetic patients with gastrointestinal symptoms.

RESULTS

Twenty of the 33 patients with STC gave a family history of constipation, including an affected identical twin and Hirschsprung's disease (n = 3). None had abnormalities on neurological examination or nerve conduction studies. Fifteen of the 33 patients had abnormalities on quantitative tests, including all six who required a colectomy. Eleven patients with STC had reduced axon-reflex sweating in the presence of normal sweat gland responses (P < 0.001, all patients with STC versus controls). Twelve patients with STC had small sensory fibre dysfunction, with significantly increased thermal thresholds (cool, P < 0.05; warm, P < 0.01); these included six of nine patients with STC and rectal hyposensation. There were similar findings on quantitative testing in diabetic patients.

CONCLUSION

Quantitative tests in patients with STC provide evidence of a small fibre neuropathy. The high incidence of a positive family history, particularly a possible association with Hirschsprung's disease, suggests a genetic basis, which deserves further investigation.

Idiopathic constipation: too few stools and too little knowledge

The precise abnormalities of colonic motility patterns in idiopathic constipation, and the alterations at the cellular, neural, myogenic and biochemical levels that underlie these patterns, are not yet understood. One promising approach in the treatment of constipation seems to be to design drugs that can stimulate GMCs to produce mass movements and consequently defaecation. This could possibly be achieved with the selective 5-HT4 receptor agonists prucalopride and SDZ HTF-919, which are currently in advanced clinical trials. Other mechanisms that provide a means to induce GMCs, such as NK1 receptor agonism, deserve further exploration.

Circulating gastrointestinal hormone abnormalities in patients with severe idiopathic constipation

OBJECTIVE

This study aimed to determine if there is an abnormality of circulating gastrointestinal hormones in patients with severe idiopathic constipation.

METHODS

Twelve patients, all female (median age 34 yr) and 12 healthy controls (eight female, median age 32 yr) were studied. A radioisotope-labeled solid/liquid meal was ingested, and the serum hormone response, as well as the relationship between serum hormones and rates of gastric emptying and small intestinal transit, were studied for 180 min postprandially.

RESULTS

Somatostatin levels were higher in patients with constipation (basal level, controls vs patients, 31 vs 57 pmol/L, p < 0.05, median values; peak level, 48 vs 60, p < 0.05). Patients showed a significantly lower somatostatin integrated incremental meal response (2182 vs 104, p < 0.05). No correlation was found between the somatostatin levels and rates of upper gastrointestinal transit in patients. Pancreatic glucagon was significantly decreased (p=0.04). Enteroglucagon levels were significantly lower (p > 0.05) in patients between 30 and 60 min after the meal. The peak found after the meal in normal subjects was absent. Basal levels of pancreatic glucagon correlated with small bowel transit by two different measures: head of meal (r=0.69, p=0.03) and cecal filling at the time of 50% gastric emptying (r=0.84, p=0.002). No significant differences between the two groups could be found for basal and peak levels at different times and integrated incremental response to the meal for insulin, gastric inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), gastrin, pancreatic polypeptide (PP), motilin, neurotensin, and peptide tyrosine tyrosine (PYY).

CONCLUSION

Patients with severe idiopathic constipation have specific abnormalities of circulating gut hormones that most likely play a role in gastrointestinal motility and that may be of pathophysiological significance.

Selective autonomic and sensory deficits in slow transit constipation

Chronic idiopathic constipation is likely to be a heterogeneous condition. Our previous studies on the stimulated sweating response suggested that autonomic dysfunction may be a cause in a subset of patients. Our aims were to test selectively the neural and sweat gland components of the sweat response and to test unmyelinated sensory fibres so as to determine whether a small fibre neuropathy is present. Twelve female patients with proven slow transit constipation and nineteen age-matched healthy volunteers took part in the study. The sensory tests included thermal thresholds and axon reflex vasodilatation in response to intradermal capsaicin, measured with a laser Doppler. Direct and axon reflex sweating was induced with intradermal methacholine and nicotine, respectively, and measured with an evaporimeter. Non-parametric tests were used for statistical comparison with a group of seven control subjects. Results are expressed as medians and range. All four patients who reported constipation from childhood had a selective deficit of unmyelinated afferent fibre function in the feet, with markedly elevated thresholds to warm sensation (controls 5.2; 4.3-10.6, patients 13.8; 11.8-16.1 delta T (degree C), P < 0.02) and heat pain (controls 10.6; 8.2-14.7, patients 18.1; 13.9-22.6 delta T (degree C), P < 0.05) and a reduced response to capsaicin (controls 47.0; 24-117, patients 13.5; 12-30 delta Flux (V), P < 0.005). In contrast, patients with adult onset constipation (n = 7) had a selective neural sweating deficit (controls 49.8; 32.0-61.8; patients 27.7; 7.3-44.3 g/m2 h, P < 0.05), indicating dysfunction of post-ganglionic sympathetic cholinergic fibres. Patients from both groups were shown to have normally functioning sweat glands in direct response to methacholine. Our findings suggest that patients with severe chronic idiopathic constipation may have selective small fibre neuropathies, of which constipation is a manifestation.

Motor abnormalities in the terminal ileum of patients with chronic idiopathic constipation

Abnormalities in oesophageal, gastric and jejunal motility have been described in patients with chronic idiopathic constipation, suggesting that this may be a panenteric disorder. To test the hypothesis that ileal motility is also abnormal in constipation, terminal ileal motility was studied in ten patients and six healthy controls by prolonged and ambulant manometry. Mean(s.e.m.) phase II activity was significantly prolonged in patients compared with controls, during wakefulness (61.6(7.3) versus 19.3(3.5) per cent, P < 0.001) and sleep (44.4(9.0) versus 1.1(0.8) per cent, P < 0.001). The mean(s.e.m.) duration of phase III fronts was shorter in patients (7.9(1.8) min) than in controls (13.2(1.3) min; P < 0.001). Retrograde propagation was seen in approximately 15 per cent of all phase IIIs in patients but not in control subjects. The mean(s.e.m.) duration of postprandial activity was significantly shorter in patients than in controls (30.1(6.2) versus 130.0(68.0) min, P < 0.001). Ileal motility is abnormal in patients with chronic idiopathic constipation. This may result from an abnormality of the enteric nervous system or abnormal modulation of this system by the central nervous system.

Constipation. Pathogenesis and management

Constipation is a collective term for different manifestations of different aetiology, pathology and treatment. It can be a symptom of organic disease or may disclose a colonic or anorectal functional disorder of unknown aetiology--this is called chronic idiopathic constipation (CIC). CIC could be due to colonic or anorectal dysmotility. The latter presents as rectal inertia or outlet obstruction. Outlet obstruction manifests with excessive straining (strainodynia), although stools are soft and bulky. Four types of strainodynia can be identified: band, sphincter, levator and detrusor. Idiopathic infrequent defecation (oligofaecorrhoea) is revealed by hypertrophy and degenerated nerve plexus of the internal anal sphincter. It presents clinically with 'cone anus'. The 'mass squeeze contraction' theory describes rectal motility; the wave starts at the rectosigmoid junction (RSJ) and spreads distally. A 'pacemaker' was suggested to exist at the RSJ, organising rectal motility. Indeed, studies on electromechanical rectal activity revealed pacesetter and action potentials originating at the RSJ. Faecoflowmetry and water enema tests are new methods for investigating anorectal dysmotility, and reflexometry is important in assessment. The treatment of CIC is problematic and controversial. However, the patient should be given the chance to try pharmacological treatment at the start before embarking on surgery. Biofeedback may be helpful, especially in outlet obstruction constipation. Sphincter myotomy and myectomy, partial rectal resection and colectomy have been used, with variable results. Medical treatment with a fibre-rich diet or orally or rectally administered laxative agents may be indicated in the treatment of constipation, especially when a cause can not be identified. However, it is important to stress that the untoward effects which may result from laxative abuse could be greater than those of constipation.

Idiopathic constipation: any movement?

Severe constipation now attracts considerable research interest. As a consequence, there have been recent advances in most aspects of this disorder. The epidemiology of this condition is now better appreciated, and subgroups of patients with different epidemiologies, symptom complexes, aetiologies, and treatments can now be distinguished. Radioisotopes enable detailed transit studies to be obtained of the entire gastrointestinal tract. Careful psychologic evaluation is an essential part of the evaluation. In young women with severe idiopathic constipation there is a decrease in propulsive mass movements, and specific colonic neurotransmitter abnormalities have been identified. Biofeedback therapy is an effective treatment for many of these patients. The variable results of surgery are now also clearly defined. Patients with chronic idiopathic intestinal pseudoobstruction can be categorized on the basis of their pathologic findings; detailed tissue studies may be required. The recognition that severe constipation encompasses various different conditions is leading to a more precise understanding of pathogenesis and treatment.