Video capsule endoscopy in inflammatory bowel disease.

Video capsule endoscopy (VCE) has evolved to become an important tool for the non-invasive examination of the small bowel, which hitherto had been relatively inaccessible to direct visualisation. VCE has been shown to play a role in monitoring the activity of small bowel Crohn's disease and can be used to assess the response to anti-inflammatory treatment in Crohn's disease. For those patients with Crohn's disease who have undergone an intestinal resection, VCE has been assessed as a tool to detect post-operative recurrence. VCE may also aid in the reclassification of patients with a diagnosis of Inflammatory Bowel Disease Unclassified to Crohn's disease. The evolution of colon capsule endoscopy (CCE) has expanded the application of this technology further. The use of CCE to assess the activity of ulcerative colitis has been described. This advance in capsule technology has also fuelled interest in its potential role as a minimally invasive tool to assess the whole of GI tract opening the possibility of its use for the panenteric assessment of Crohn's disease. VCE is a safe procedure. However, the risk of a retained capsule is higher in patients with suspected or confirmed Crohn's disease compared with patients having VCE examination for other indications. A retained video capsule is rare after successful passage of a patency capsule which may be utilised to pre-screen patients undergoing VCE. This paper describes the use of VCE in the assessment of inflammatory bowel disease.

Strategies for detecting colon cancer and dysplasia in patients with inflammatory bowel disease.

The risk of colorectal cancer in patients with long-standing ulcerative colitis or colonic Crohn's disease is increased. Patients with long-standing ulcerative colitis are offered enrollment into programs of endoscopic surveillance. Although direct evidence for a protective effect of surveillance against death from colorectal cancer is limited, colorectal cancer is detected at an earlier stage and the corresponding prognosis is better. Targeting biopsies using pancolonic chromoendoscopy is superior to taking multiple random biopsies for the detection of dysplasia at colonoscopy.

Colon cancer: a civilization disorder.

Colorectal cancer arises in individuals with acquired or inherited genetic predisposition who are exposed to a range of risk factors. Many of these risk factors are associated with affluent Western societies. More than 95% of colorectal cancers are sporadic, arising in individuals without a significant hereditary risk. Geographic variation in the incidence of colorectal cancer is considerable with a higher incidence observed in the West. Environmental factors contribute substantially to this variation. A number of these risk factors are associated with a Western lifestyle and could be considered a product of 'civilization'. Recently, smoking has been recognized as a risk factor. Energy consumption also influences colorectal cancer risk, with obesity increasing risk and exercise reducing risk. However, the strongest contribution to environmental risk for colorectal cancer is dietary. Consumption of fat, alcohol and red meat is associated with an increased risk. Fresh fruit and vegetables and dietary fibre may be protective. Much has been learnt recently about the molecular pathogenesis of colorectal cancer. Colorectal cancer always arises in the context of genomic instability. There is inactivation of the tumour suppressor genes adenomatous polyposis coli, p53, transforming growth factor-ß, activation of oncogene pathways including K-ras, and activation of the cyclooxygenase-2, epidermal growth factor receptor and vascular endothelial growth factor pathways. The mechanisms by which some environmental factors modify the mutation risk in these pathways have been described.

The role of the eosinophil-selective chemokine, eotaxin, in allergic and non-allergic airways inflammation

Blood eosinophilia and tissue infiltration by eosinophils are frequently observed in allergic inflammation and parasitic infections. This selective accumulation of eosinophils suggested the existence of endogenous eosinophil-selective chemoattractants. We have recently discovered a novel eosinophil-selective chemoattractant which we called eotaxin in an animal model of allergic airways disease. Eotaxin is generated in both allergic and non-allergic bronchopulmonary inflammation. The early increase in eotaxin parallel eosinophil infiltration in the lung tissue in both models. An antibody to IL-5 suppressed lung eosinophilia, correlating with an inhibition of eosinophil release from bone marrow, without affecting eotaxin generation. This suggests that endogenous IL-5 is important for eosinophil migration but does not appear to be a stimulus for eotaxin production. Constitutive levels eotaxin observed in guinea-pig lung may be responsible for the basal lung eosinophilia observed in this species. Allergen-induced eotaxin was present mainly in the epithelium and alveolar macrophages, as detected by immunostaining. In contrast, there was no upregulation of eotaxin by the epithelial cells following the injection of Sephadex beads and the alveolar macrophage and mononuclear cells surrounding the granuloma were the predominant positive staining cells. Eotaxin and related chemokines acting through the CCR3 receptor may play a major role in eosinophil recuitment in allergic inflammation and parasitic diasease and thus offer an attractive target for therapeutic intervention.