A controlled study of faecal distribution in ulcerative colitis and proctitis

Characterization of ulcerative colitis-associated constipation syndrome (proximal constipation)

BACKGROUND

The syndrome of constipation with other abdominal symptoms ("proximal constipation") in ulcerative colitis (UC) is commonly recognized by practitioners but is poorly described, with no recognized definition and little understanding with regard to prevalence and effect of therapies on disease outcomes. This study aimed to address these issues in a cross-sectional, consecutive series of patients with UC.

METHODS

A working definition of proximal constipation was established. Consecutive patients were recruited, and their disease activity, recent medications, and investigations plus abdominal symptoms were assessed at a study visit. Relevant clinical data were also extracted from medical records.

RESULTS

Of 125 patients with UC, (mean age 47, range 14-84 years, 61 male), 58 (46%) fulfilled the definition of proximal constipation. The main symptoms were reduced stool frequency (69%), hard stools (43%), abdominal pain (40%), excessive flatus (29%), straining (24%), and sensation of incomplete emptying (14%). Proximal constipation was associated with female gender (OR 3.45 [1.45-8.24]), left-sided (OR 2.84 [1.14-7.11]) and concurrently active disease (OR 5.56 [1.96-16.67]), but not age, disease duration or therapy. A total of 88% had an increase in anti-inflammatory therapy, with the use of laxatives or fiber supplements in 63% compared with 1.4% of those without proximal constipation.

CONCLUSIONS

Proximal constipation is common, and its risk increases in active and distal disease, especially in women. Validation of its definition and evaluation of therapeutic strategies are needed. A new term "ulcerative colitis-associated constipation syndrome" is proposed to more accurately depict its nature.

Simulated comparison of topical and oral formulations of 5-aminosalicylate for the treatment of ulcerative colitis

BACKGROUND

5-Aminosalicylate (5-ASA) formulations are approved for the treatment of ulcerative colitis (UC). Determination of the colonic pharmacokinetics of 5-ASA is challenging. A dynamic model of 5-ASA colonic amounts after oral delayed-release 5-ASA (Asacol), oral extended delayed-release 5-ASA (Lialda), 5-ASA enema (Rowasa), foam and suppositories (Canasa) was developed to determine the colonic kinetics of these agents.

METHODS

We created a model with Stella software. Colonic 5-ASA in the right, transverse, descending, sigmoid colon, and rectum were estimated for adults after recommended doses of the above formulations. Simulations of active mild/moderate UC and in remission were performed and compared using Student's t-test for differences in means.

RESULTS

For UC in remission, the highest amounts of 5-ASA were from Asacol in the right and transverse colon (P < 0.01), Lialda in the descending and sigmoid colon (P < 0.01), and Rowasa in the rectum (P < 0.01). For active UC, sigmoid amounts were highest with foam (P < 0.01), and rectal amounts highest with Rowasa (P < 0.01). Differences in rectosigmoid amounts of 5-ASA from enemas and suppositories for UC in remission occurred based on the relationship between the timing of administration relative to the daily bowel movement (P < 0.01).

CONCLUSIONS

Compared to Asacol, Lialda results in higher 5-ASA amounts in the left colon. Asacol with Rowasa provides highest 5-ASA amounts across the entire colon. Higher 5-ASA amounts from topical formulations occur when the insertion occurs soon after the daily bowel movement. This model provides a rationale for further investigation.

A dynamic model of colonic concentrations of delayed-release 5-aminosalicylic acid (Asacol)

BACKGROUND

5-ASA in a pH sensitive tablet (Asacol) is administered as three doses/day to treat ulcerative colitis. Once daily dosing may improve patient adherence. Simulation of colonic levels of 5-ASA can be used to compare dosing regimens.

AIM

To create a dynamic model of colonic concentrations of delayed-release 5-aminosalicylic acid (Asacol).

METHODS

Using published data, we created a computer model with STELLA software to simulate amounts of colonic 5-ASA in the total colon, right, transverse, descending and sigmoid/rectum after daily and three time/day Asacol.

RESULTS

The model predicted similar total and regional amounts of 5-ASA with both regimens. Distribution of 5-ASA was 38% in the right colon, 33% in the transverse colon and 14% each in the descending and sigmoid/rectal colon. Simulated increases in colonic motility and defecation rate exaggerated this 5-ASA distribution, resulting in negligible amounts of 5-ASA in the sigmoid/rectal region.

CONCLUSIONS

This computer model suggests that Asacol can be administered as a single daily dose. The model supports experimental and clinical observations that alternate dose or route of administration may be necessary to achieve adequate 5-ASA amounts in the distal colon during acute exacerbations of ulcerative colitis. This simulation cannot account for all sources of variability in the clinical setting, but provides a rationale for further investigation.

Colorectal motor and sensitivity features in patients affected by ulcerative proctitis with constipation: a radiological and manometric controlled study

BACKGROUND AND AIM

Constipation may be present in ulcerative proctitis (UP), but its pathogenesis has not yet been evaluated. The aim of this article is to investigate functional and morphologic features of the anorectal region in patients with UP and constipation.

MATERIALS AND METHODS

Eleven patients with quiescent clinical, endoscopic, and histological UP and constipation and 10 patients with functional constipation (FC) underwent radiologic evaluation of intestinal transit time, anorectal manometry, and defecography. Transit time was measured with radiograms at 72 h after ingestion of radiopaque markers. Manometry was carried out using a continuous perfused catheter and a balloon inflated with increasing volumes of air. Defecography was performed after the injection of a barium-sulfate solution in the rectum, with the registration of videotapes during straining, squeezing, and evacuation.

RESULTS

Manometry showed in UP significantly lower values of rectal compliance than those in FC (3.10 and 5 mL/mmHg, respectively) (P = 0.03). Rectal sensitivity threshold was increased but without significant differences in UP and FC (30 and 50 mL air, respectively). At defecography, the median value of rectosacral space was increased in UP in comparison with FC (1.30 vs 0.8; P = 0.002). Lateral rectal diameter in UP was lower than in FC (6 and 8.8 cm, respectively; P = 0.016). Nonsymptomatic rectocele, mucosal prolapse, descending perineum, and abdominopelvic dyssynergy were equally present in UP and FC. The majority of UP patients showed a prolonged intestinal transit time similar to FC patients, and, more frequently, they showed low transit in the left colon in comparison with the right colon in comparison with FC patients.

CONCLUSIONS

This study suggests that constipation in UP may be correlated with rectal fibrosis, which reduces the transit of stools from the left colon. The concomitance of asymptomatic anorectal organic or functional alteration may contribute to worsen constipation.

Limited exposure of the healthy distal colon to orally-dosed formulation is further exaggerated in active left-sided ulcerative colitis

BACKGROUND

Active distal ulcerative colitis is often resistant to topically acting oral formulations. We speculated that the left side of the colon is underexposed to orally-dosed topical agents in patients with active distal colitis.

METHODS

Twenty-two healthy volunteers (12 males, aged 22-47 years), and 10 patients (6 males, aged 33-73 years) with active left-sided ulcerative colitis ingested a Eudragit-coated gelatine capsule containing 111In-labelled amberlite resin on four successive days. Regional colonic distribution, transit times and percentage of daily dose resident were calculated from the average of four serial gamma camera images on the 4th day.

RESULTS

(mean [95% CI]). When compared to controls, patients with colitis had significantly faster total colon transit (24.3 h [9.5-39.1] vs. 51.7 h [41.1-62.3]) as well as faster proximal colon transit (18.7 h [9.1-28.3] vs. 36.7 [28.5-44.9]), and distal colon transit (3.1 h [-0.5 to 6.8] vs. 15.0 h [10.5-19.5]), respectively (all P < 0.01). Material was asymmetrically distributed in health (proximal colon 69% [63-76] vs. distal colon 31% [24-37]). This asymmetry was more extreme in colitis, with corresponding values of 91% [85-96] vs. 9% [4-15]. As a result colitics had less material in the left-sided colon (9% [4-15] vs. 31% [24-37]), P < 0. 001. Colitics had a significantly lower percentage of the daily dose resident within the left side of the colon compared to controls (13% [-2 to 28] vs. 63% [44-81]), P < 0.01.

CONCLUSIONS

Delayed release oral formulation is asymmetrically distributed within the colon in health. This asymmetry is exaggerated in active left-sided ulcerative colitis and, together with faster colonic transit, results in reduced exposure of the distal colon to orally-dosed topical agents.

Comparative bioavailability of 5-aminosalicylic acid from a controlled release preparation and an azo-bond preparation

BACKGROUND

Knowledge of the bioavailability of 5-aminosalicylic acid (5-ASA, mesalazine) from the different 5-ASA-containing drugs is important for rational therapy of inflammatory bowel diseases.

METHODS

The local and systemic bioavailability of 5-ASA from a controlled release 5-ASA preparation (Pentasa--2, 4 or 6 g/day) was investigated and compared with the azo-bond 5-ASA preparation olsalazine (Dipentum--2 g/day) in 13 healthy volunteers during steady state conditions.

RESULTS

The therapeutically relevant parameter of 5-ASA at the rectal level, expressed as the mean concentration in faecal water, showed a significant trend towards higher concentrations with increasing Pentasa dose: 9.2 mmol/L, 19.0 mmol/L and 24.4 mmol/L, respectively. The concentration of olsalazine 2 g/day was 16.0 mmol/L. The concentration of the metabolite N-acetyl-5-aminosalicylic acid (Ac-5-ASA) did not rise with increasing Pentasa dose, indicating saturable presystemic acetylating capacity of 5-ASA. Total urinary excretion of 5-ASA and Ac-5-ASA, as a percentage of the daily ingested 5-ASA dose, remained constant on the three Pentasa doses, but there was a significant increase in the 5-ASA fraction. Mean steady state plasma concentrations of 5-ASA and Ac-5-ASA were significantly higher on Pentasa 4 g/day and 6 g/day than on 2 g/day. Values on Pentasa 2 g/day were comparable with those on olsalazine 2 g/day.

CONCLUSIONS

The study confirmed that 5-ASA is released from Pentasa in a predictable manner, the amount released increasing with dose. Olsalazine is an excellent generator of 5-ASA in the colon.

Bioavailability of 5-aminosalicyclic acid from slow release 5-aminosalicyclic acid drug and sulfasalazine in normal children

The bioavailability of a controlled release 5-aminosalicyclic acid preparation (Pentasa) was investigated in nine healthy children after a medication period of six days (1000 mg/day) and compared with sulfasalazine (Salazopyrin) (2000 mg/day). The local bioavailability in the distal gut lumen, reflected by the 5-aminosalicylic acid concentration in the fecal water, showed comparable values after Pentasa (4.44 mmol/liter) and Salazopyrin (6.25 mmol/liter). The concentration of N-acetyl-5-ASA was significantly higher after Pentasa, reflecting the more proximal release of 5-aminosalicyclic acid compared with Salazopyrin. No relation was found between the 5-aminosalicylic acid fecal water concentration water concentration and the 5-aminosalicylic acid dose per kilogram of body weight. The urinary excretion of 5-aminosalicylic acid and N-acetyl-5-aminosalicylic acid was higher after Pentasa than after Salazopyrin (32% vs 25%). Dose interval plasma concentration curves showed low values after both preparations. Based on the concept that the fecal water concentration is decisive for the efficacy of 5-aminosalicylic acid in distal inflammatory bowel disease, Pentasa treatment offers a relevant alternative in cases of Salazopyrin intolerance or allergy in children. The higher systemic bioavailability from Pentasa warrants monitoring of the renal function.

Prevalence of proximal faecal stasis in active ulcerative colitis

Proximal faecal stasis may occur when faecal matter accumulates in the uninflamed colon above an area of active ulcerative colitis. This phenomenon is thought to be the cause of symptoms in some patients with distal disease. It is not known, however, how often patients with active distal colitis exhibit slow colonic transit. Fifty two consecutive patients with active ulcerative colitis each ingested 10 radio-opaque markers nightly for 14 days. Minimum colonic transit times were derived from counts of retained markers shown by plain abdominal radiography on the 15th day. The transit times for each patient were related to their disease extent and bowel frequency. Four patients had colonic transit times greater than one week and two others had evidence of relative stasis. The results indicate that approximately 10% of attacks of distal colitis are associated with faecal stasis.

Disposition of 5-aminosalicylic acid from 5-aminosalicylic acid-delivering drugs during accelerated intestinal transit in healthy volunteers

In eight healthy volunteers accelerated intestinal transit time was induced with bisacodyl, and urinary and faecal excretion of sulphasalazine, olsalazine, 5-aminosalicylic acid (5-ASA), and acetyl-5-ASA was studied after a single oral dose of 3.3 mmol sulphasalazine, olsalazine, Pentasa, and Salofalk and 2.6 mmol of Asacol. The faecal and urinary excretion of acetyl-5-ASA was lowest after intake of sulphasalazine and olsalazine and highest after intake of Pentasa and Salofalk. The figures for Asacol were intermediate. This indicates insufficient release of 5-ASA from sulphasalazine and olsalazine. When the results of this study are compared with those of a previous study without accelerated transit time, the disposition of 5-ASA from all the 5-ASA-delivering drugs is influenced unfavourably by an accelerated gut transit but most pronounced in the case of sulphasalazine, olsalazine, and Asacol. The impaired release from the azo compounds sulphasalazine and olsalazine is a result of far less complete splitting of the diazo bond.