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Crohn's disease (CD) is a chronic inflammatory bowel disease that may involve the whole gut. Marked intestinal T cell and macrophage activation is a key feature of the disease. Polymorphonuclear cell infiltration is also observed in the diseased gut, mainly during active inflammation. Scintigraphic detection of granulocytes and activated lymphocytes infiltrating the gut wall may be useful in identifying a subgroup of patients with clinically inactive CD who are undergoing early clinical relapse. The aims of the present study were (a) to compare the effectiveness of scintigraphy with (99m)Tc-labelled interleukin-2 ((99m)Tc-IL2) and with (99m)Tc-HMPAO labelled granulocytes ((99m)Tc-WBC) in detecting the presence and extent of bowel inflammation in patients with long-term inactive CD (12 months) and (b) to assess the accuracy of these techniques in predicting future disease relapse. We studied 29 patients with ileal and/or colonic CD in stable clinical remission (Crohn's Disease Activity Index150 for at least 12 months) using both (99m)Tc-IL2 and (99m)Tc-WBC scintigraphy in order to evaluate the extent of acute and chronic inflammation in the bowel. Planar and single-photon emission tomography images were acquired in each patient at 1 h p.i. For quantitative analysis of (99m)Tc-IL2 uptake, the abdomen was divided into 32 regions of interest. Despite the absence of symptoms, 18 patients (62%) showed a positive (99m)Tc-IL2 and 18 (62%) a positive (99m)Tc-WBC scan. Only 12 patients (41.4% of the total group) were positive on both scans, and the sites of IL2 and granulocyte bowel uptake were usually located in different segments, indicating that in CD, acute and chronic inflammation can be present in different sites. As far as the prognostic role of the two scans in predicting future disease relapse is concerned, both (99m)Tc-IL2 and (99m)Tc-WBC scintigraphy showed a high negative predictive value (1.00 and 0.91, respectively) but a weak positive predictive value (0.44 and 0.39, respectively). Nevertheless, Kaplan-Meier curves generated between scintigraphic findings and time free from disease relapse were statistically different only for (99m)Tc-IL2 scintigraphy (log-rank test, P=0.013). These results indicate that (99m)Tc-IL2 scintigraphy can be useful in selecting CD patients in clinical remission who could benefit from preventive therapy to avoid disease relapse.

We have evaluated morphologic alterations and epithelial cell apoptosis and proliferation of colonic mucosa in the acute and chronic phases of DSS-induced colitis. Colitis was induced in Sprague-Dawley rats by 7 days of 4% DSS oral administration followed by 7 days of tap water for one, two, and three cycles. Control rats receved tap water only. Morphological changes in colonic mucosa were evaluated and scored by light and scanning electron microscopy. Apoptosis was studied by TUNEL assay and cell proliferation by Ki-67 immunoreaction. The expression of both proapoptotic (Fas, FasL, Bax, p53) and antiapoptotic (Bcl2) cellular proteins was determined by immunohistochemistry. Morphologic assessment showed the most severe colonic epithelial lesions and inflammation in the distal colon with a trend to increasing severity from the first to the third DSS cycle. In DSS rats, the epithelial apoptotic index increased 20-fold after the first cycle and 120-fold after the second and third cycles compared with the controls; in the same way, the expression index of proapoptotic proteins (Fas, FasL, Bax, p53) dramatically increased. The proliferative index increased about 40 to 60-fold compared to controls, with no difference among the three DSS cycles. In conclusion, DSS-induced colitis in rats, which has many structural and ultrastructural features similar to those seen in human ulcerative colitis, is a suitable model for studying increased epithelial apoptosis and proliferation. Further studies employing this model will permitt two hypotheses to be tested. (1) Increased apoptosis may lead to a breakdown of the epithelial barrier function and facilitate the mucosal invasion of intraluminal microorganisms and/or antigens. (2) Abnormal and persistent epithelial hyperproliferation could be causally related to the development of colorectal cancers in the setting of chronic colonic inflammation.

Butyrate represents the main source of energy for colonic epithelial cells; however, its availabilty/utilization is impaired in ulcerative colitis (UC). In the present randomized, double-blind, placebo-controlled pilot study, the safety and efficacy of colonic targeted oral sodium butyrate tablets, coated with a pH-dependent soluble polymer, have been evaluated in ulcerative colitis. Thirty patients with mild to moderate colitis underwent a six-week course of oral sodium butyrate (4 g/day) plus oral mesalazine (2.4 g/day), (Group A) or of oral mesalazine plus placebo (Group B). Clinical, endoscopic, and histologic data were collected at the beginning and the end of the study. Twenty-five patients completed the study (12 in group A, 13 in group B). No untoward side effects were reported. In group A, seven patients underwent remission and four improved; in Group B the numbers were 5 and 5, respectively. After treatment, all clinical parameters had significantly improved in both treatment arms compared to pretreatment findings. The UC disease activity index (UCDAI) score decreased from 7.27 ± 2.02 to 2.58 ± 2.19 (P < 0.05) in the combined treatment group and from 6.07 ± 1.60 to 3.46 ± 1.98 (P < 0.05) in group B. The endoscopic and histologic scores also significantly improved after treatment in both groups (P < 0.05). The difference between the two treatment arms was not significant, but a significantly better improvement vs baseline values (P < 0.05) was observed in the combined treatment group vs the mesalazine group, when considering both the clinical index (Δ9.58 ± 4.19 vs 5.92 ± 3.48) and the UCDAI score (Δ4.67 ± 2.19 vs 2.54 ± 2.18). A more favorable trend, although not significant, was observed for all individual parameters in group A. In conclusion, results of the present pilot study indicate that oral butyrate is safe and well tolerated. These data also suggest that oral butyrate may improve the efficacy of oral mesalazine in active ulcerative colitis and prompt the need of a large scale investigation to confirm the present findings.

Aim of this study was to assess the structural,ultrastructural, immunohistochemical, and clinicalaspects in Sprague-Dawley rats with dextrane sulfatesodium (DSS)-induced colitis. Colitis was induced in Sprague-Dawley rats by seven days of DSSoral administration followed by seven days of tap wateronly (for one, two and three cycles). Controls were fedwith water only. Segments of proximal, mid-, and distal colon of each animal were adequatelyprepared for light and scanning electron microscopeobservations. The severity of the lesions was scoredhistologically. For immunohistochemical study, acocktail of S-100, NSE, and antineurofilament antibodieswas used. Symptoms such as weight, feces consistency,diarrhea, hematochezia were recorded daily. From aclinical point of view symptoms appeared significantly later after the first cycle than after thesecond and third cycles and lasted significantly longerin the second and third cycles. Treated rats showed aslower weight gain rate by 20% compared to controls, and the whole colon length appeared to besignificantly shorter after colitis induction comparedto controls. Structural observations by light microscopyshowed prominent involvement of the distal colon. Immunohistochemical study of both submucosaland myoenteric nerve plexuses was similar to controls.Scanning electron microscope observations of the colonicmucosal surface in colitis rats showed a complete subversion of its architecture, characterizedby dilatations of gland crypt openings, dropout ofgoblet cells, and inhomogeneous distribution or lack ofmicrovilli. These were most evident after the third cycle. In conclusion, experimental DSS colitisin SD rats appeared to be highly reproducible and sharedmost features with human UC, not only from a structuraland clinical but also from an ultrastructural point of view.

Ulcerative colitis (UC) is associated with low intracolonic pH and unbalanced transmucosal ionic exchanges. Along the gastrointestinal tract carbonic anhydrase isoenzyme I (CA-I) is specifically expressed in colon epithelium and is involved in mucosal control of ion, fluid, and acid-base balance. Since altered CA-I expression may play some role in UC, CA-I was measured at the mRNA and protein level and carbonic anhydrase (CA) enzyme activity was determined in colon biopsies of 14 UC patients (6 remission, 4 mild, 4 moderate UC) and of 12 healthy subjects. Patients with mild or moderate UC showed a significant reduction of CA-I mRNA and protein and of total CA activity in the inflamed mucosa compared to controls. Patients with UC in remission showed a pattern of CA-I expression and CA activity similar to controls. This is the first report showing a reduction in the expression of CA-I in active UC.

Mature goblet cells filled with mucin ready for secretion represent about one third of the cells in primary cultures of human colonocytes. In the present study characterization of the mucins produced by cultured human colonocytes was made by histochemical methods by lectin and monoclonal antibody binding. Two monoclonal antibodies and three lectins (Dolichos biflorus (DBA), Helix pomatia (HPA) and Arachis hypogea (PNA) recognizing epitopes or sugar haptens characteristic of different stages of mucin glycoprotein maturation, were employed. The reactivity to these probes was tested both on cultured colonocytes and on tissue sections of the normal colon mucosa. The results show that the mucins produced in culture are glycosylated to the mature form, as they show the same reactivity to lectins and antibodies of the mucins expressed in tissue sections of the normal colon mucosa. In addition, it is demonstrated that cultured human colonocytes do not express mucins reactive to PNA, which are characteristic of tumors. Since the cultured colonocytes maintain the expression of differentiated functions for at least three days, they may offer a useful model to study metabolism, function and regulation of colon mucins in health and disease.

Nine patients with distal ulcerative colitis refractory to standard therapy were treated with intrarectal instillation of a sodium butyrate solution and 5-ASA. A marked clinical, endoscopical and, to a smaller extent, histological improvement was observed in seven of nine patients. The clinical improvement usually occurred within the second week of therapy, and thus earlier than in previous cases treated with butyrate alone. This preliminary experience suggests that the combined butyrate-5-ASA treatment may prove a useful therapeutic tool in refractory distal ulcerative colitis and possibly increase the effectiveness of the individual therapeutic regimens.

Colon cells from patients with ulcerative colitis utilize short-chain fatty acids inefficiently and may be exposed to decreased concentrations of these compounds. To test whether irrigation of the inflamed mucosa with short-chain fatty acids is useful, we conducted a six-week preliminary trial in 12 patients with distal colitis. Each patient used twice daily rectal irrigations with 100 ml of a solution containing acetate (80 mM), propionate (30 mM), and butyrate (40 mM). Two patients stopped at three weeks, one because of no improvement and the other because of complete resolution of symptoms. Of the 10 who completed the trial, nine were judged to be at least much improved and showed a change in a mean disease activity index score from 7.9 +/- 0.3 (SE) to 1.8 +/- 0.6 (SE) (P less than or equal to 0.002) and in a mucosal histology score from 7.7 +/- 0.7 (SE) to 2.6 +/- 0.7 (SE) (P less than or equal to 0.002). Thus, ulcerative colitis patients appear to benefit from increased contact with or higher than usual levels of these critical energy substrates.