Histological Outcomes and Predictive Value of Faecal Markers in Moderately to Severely Active Ulcerative Colitis Patients Receiving Infliximab.

BACKGROUND AND AIMS: Histological healing has emerged as a promising therapeutic goal in ulcerative colitis. This is especially important in the context of biological therapies. The objectives of the present study were to investigate the ability of infliximab to induce histological remission in ulcerative colitis [UC] patients and to explore the utility of faecal calprotectin and lactoferrin in predicting histological activity. METHODS: Multi-centre, single-cohort, open-label, 52-week trial including moderately to severely biological-naïve UC patients receiving intravenous infliximab [5mg/kg]. The primary outcome was the proportion of patients with histological remission [Geboes index ≤ 3.0] after 8 weeks of treatment, scored by two independent pathologists. RESULTS: Twenty patients were included. The rate of histological remission increased from 5% at baseline to 15% and 35% at Week 8 and Week 52, respectively. At Week 8, 40% of patients were in clinical remission [Mayo ≤ 2] and 45% achieved mucosal healing [Mayo endoscopy subscore 0-1]. At Week 52, 25% of patients had clinical, endoscopic and histological remission. Faecal calprotectin and lactoferrin showed the highest correlation with histological activity at Week 8 (area under the curve [AUC] 94%, p = 0.017; and 96%, p = 0.013, respectively) and both markers revealed an excellent positive predictive value for this outcome at this time point [100%, p = 0.017; and 94%, p = 0.013, respectively]. CONCLUSIONS: Infliximab was able to induce histological remission. There was a good agreement between histology and faecal biomarkers. Faecal calprotectin and lactoferrin were good predictors of histological remission. Our data support inclusion of histology as a treatment target complementary to endoscopy in clinical trials when evaluating therapeutic response in UC.

The influence of inulin on the absorption of nitrogen and the production of metabolites of protein fermentation in the colon.

In the present study, the production and fate of bacterial metabolites in the colon were investigated in a direct way using two substrates labelled with stable isotopes: lactose [(15)N,(15)N]ureide as a source of labelled ammonia and egg proteins intrinsically labelled with [(2)H4]tyrosine as a precursor of [(2)H4]p-cresol. Both ammonia and phenolic compounds are believed to be carcinogenic. Stimulation of carbohydrate fermentation in order to prevent accumulation of these toxic metabolites was induced by inclusion of inulin in a test meal or by addition of inulin to the daily diet, allowing us to distinguish between changes induced by the actual presence of a fermentable carbohydrate and effects caused by a long-term dietary intervention. When a single dose of inulin was administered together with the labelled substrates, a significant increase in faecal (15)N excretion, accompanied by a proportional decrease in urinary (15)N excretion was observed, probably reflecting an enhanced uptake of ammonia for bacterial biosynthesis, since an increased concentration of labelled N in bacterial pellets was found. A statistically significant reduction of urinary [(2)H4]p-cresol excretion was also noted. Upon supplementation of inulin to the daily diet during 4 weeks, however, only a tendency towards decreased urinary excretion of both labelled and unlabelled p-cresol was noted. Further studies are warranted to confirm these results in a larger cohort.

Medical therapy for Crohn's disease strictures.

Intestinal fibrostenosis is a frequent and debilitating complication of Crohn's disease (CD), not only resulting in small bowel obstruction, but eventually in repeated bowel resection and short bowel syndrome. Over one third of patients with CD have a clear stenosing disease phenotype, often in the absence of luminal inflammatory symptoms. Intestinal fibrosis is a consequence of chronic transmural inflammation in CD. As in other organs and tissues, phenotypic transformation and activation of resident mesenchymal cells, such as fibroblasts and smooth muscle cells, underlie fibrogenesis in the gut. The molecular mechanisms and growth factors involved in this process have not been identified. However, it is clear that inflammatory mediators may have effects on mesenchymal cells in the submucosa and the muscle layers that are profoundly different from their action on leukocytes or epithelial cells. Transforming growth factor-beta (TGF-beta), for instance, has profound anti-inflammatory activity in the mucosa and probably serves to keep physiologic inflammation at bay, but at the same time it appears to be driving the process of fibrosis in the deeper layers of the gut. Tumor necrosis factor, on the other hand, has antifibrotic bioactivity and pharmacologic inhibition of this cytokine carries a theoretical risk of enhanced stricture formation. Endoscopic management of intestinal strictures with balloon dilation is an accepted strategy to prevent or postpone repeated surgery, but careful patient selection is of paramount importance to ensure favorable long-term outcomes. Specific medical therapy aimed at preventing or reversing intestinal fibrosis is not yet available, but candidate molecules are emerging from research in the liver and in other organs.

Anti-tumor necrosis factor treatment restores the gut barrier in Crohn's disease.

OBJECTIVES: A primary defect of the tight junctions and, hence, increased intestinal epithelial permeability has been proposed as a basic pathogenic event in Crohn's disease. Challenge of the mucosal immune system by the commensal gut flora would then result in chronic inflammation. Alternatively, increased permeability could be the result of inflammation. Our aim was to study intestinal permeability in refractory Crohn's disease before and after treatment with monoclonal chimeric antibodies directed against tumor necrosis factor (TNF) to investigate whether the abnormal permeability persists after control of inflammation. METHODS: Twenty-three patients with active Crohn's disease were evaluated before and 4 wk after a single infusion of 5 mg/kg infliximab. Intestinal permeability was studied by measurement of urinary excretion of 51Cr-EDTA after oral intake. RESULTS: The increased permeation of 51Cr-EDTA through the small intestine (1.63% interquartile range [IQR] 1.06-2.07) and the overall permeation (3.27% IQR 2.40-4.38) before therapy decreased significantly after infliximab infusion to values (1.04% IQR 0.74-1.54 and 2.42% IQR 2.03-2.80, respectively) in the range of those found in normal volunteers (1.12% IQR 0.85-1.58 and 2.28% IQR 1.88-2.86, respectively). CONCLUSION: Inhibiting the proinflammatory cytokine tumor necrosis factor dramatically reduces gut inflammation and largely restores the gut barrier in Crohn's disease. Our data confirm the central role of TNF in gut barrier modulation in inflammatory conditions in vivo.