Review article: exploration of the genetic aetiology of inflammatory bowel disease--implications for diagnosis and therapy

Small bowel capsule endoscopy in ulcerative colitis: the capcolitis study: a prospective observational study

BACKGROUND

Clinical phenotypes in inflammatory bowel disease (IBD) patients include ulcerative colitis (UC) and Crohn's disease (CD). Moreover, genetic aetiology studies suggest a continuum of phenotypes from exclusively ileal to left-sided colonic disease.

PATIENTS AND METHODS

A nationwide registry (BioColitis Registry) prospectively recorded ∼900 UC-patients in Germany and in the CapColitis substudy, small bowel capsule endoscopy (SBCE) was consecutively offered at participating centres. The primary objective was to investigate the presence of small bowel lesions. In total, 127 UC-patients were included.

RESULTS

SBCE was evaluable in 125 of 127 UC-patients. Small bowel lesions were found in 16/125 (13%) patients, of which nine were classified as clinically significant [backwash ileitis (n=4) or lesions suggestive of CD (n=5)], and seven were not significant [biopsy-induced lesions (n=3) or single small bowel lesions (n=4)]. The SBCE results prompted diagnostic workups in all patients with clinically relevant lesions, and all patients with lesions suggestive for CD (4%) were re-classified as CD by the treating physicians.

CONCLUSION

Systematic examination of 125 consecutive UC-patients failed to confirm a clinically important phenotype overlap with CD, as suggested by genetic aetiology studies. In five patients (4%) with small bowel lesions, the diagnosis was changed to CD.

Irritable bowel syndrome: A disease still searching for pathogenesis, diagnosis and therapy

Irritable bowel syndrome (IBS) is the most frequently diagnosed functional gastrointestinal disorder in primary and secondary care. It is characterised by abdominal discomfort, pain and changes in bowel habits that can have a serious impact on the patient’s quality of life. The pathophysiology of IBS is not yet completely clear. Genetic, immune, environmental, inflammatory, neurological and psychological factors, in addition to visceral hypersensitivity, can all play an important role, one that most likely involves the complex interactions between the gut and the brain (gut-brain axis). The diagnosis of IBS can only be made on the basis of the symptoms of the Rome III criteria. Because the probability of organic disease in patients fulfilling the IBS criteria is very low, a careful medical history is critical and should pay particular attention to the possible comorbidities. Nevertheless, the severity of the patient’s symptoms or concerns sometimes compels the physician to perform useless and/or expensive diagnostic tests, transforming IBS into a diagnosis of exclusion. The presence of alarming symptoms (fever, weight loss, rectal bleeding, significant changes in blood chemistry), the presence of palpable abdominal masses, any recent onset of symptoms in patient aged over 50 years, the presence of symptoms at night, and a familial history of celiac disease, colorectal cancer and/or inflammatory bowel diseases all warrant investigation. Treatment strategies are based on the nature and severity of the symptoms, the degree of functional impairment of the bowel habits, and the presence of psychosocial disorders. This review examines and discusses the pathophysiological aspects and the diagnostic and therapeutic approaches available for patients with symptoms possibly related to IBS, pointing out controversial issues and the strengths and weaknesses of the current knowledge.

ESPEN Guidelines on Parenteral Nutrition: gastroenterology

Undernutrition as well as specific nutrient deficiencies has been described in patients with Crohn's disease (CD), ulcerative colitis (UC) and short bowel syndrome. In the latter, water and electrolytes disturbances may be a major problem. The present guidelines provide evidence-based recommendations for the indications, application and type of parenteral formula to be used in acute and chronic phases of illness. Parenteral nutrition is not recommended as a primary treatment in CD and UC. The use of parenteral nutrition is however reliable when oral/enteral feeding is not possible. There is a lack of data supporting specific nutrients in these conditions. Parenteral nutrition is mandatory in case of intestinal failure, at least in the acute period. In patients with short bowel, specific attention should be paid to water and electrolyte supplementation. Currently, the use of growth hormone, glutamine and GLP-2 cannot be recommended in patients with short bowel.

Management of Crohn's disease in adults

Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research, derived from extensive review of published literature. When data that will withstand objective scrutiny are not available, a recommendation may be made based on a consensus of experts. Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of choices in any health-care problem, the physician should select the course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee. Expert opinion is solicited from the outset for the document. The quality of evidence upon which a specific recommendation is based is as follows: Grade A: Homogeneous evidence from multiple well-designed randomized (therapeutic) or cohort (descriptive) controlled trials, each involving a number of participants to be of sufficient statistical power. Grade B: Evidence from at least one large well-designed clinical trial with or without randomization, from cohort or case-control analytic studies, or well-designed meta-analysis. Grade C: Evidence based on clinical experience, descriptive studies, or reports of expert committees. The Committee reviews guidelines in depth, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time.

-137 (G/C) IL-18 promoter polymorphism in patients with inflammatory bowel disease

OBJECTIVE

There is strong evidence that genetic factors contribute to the susceptibility for inflammatory bowel diseases (IBD). Recently, IL-18 promoter polymorphisms were characterized as risk factors for inflammatory diseases such as sepsis, asthma and adult-onset Still's disease. The aim of this study was to determine whether the -137 (G/C) IL-18 promoter polymorphism was associated with IBD susceptibility.

MATERIAL AND METHODS

For association analysis, 470 patients with Crohn's disease (CD), 235 unrelated patients with ulcerative colitis (UC) and 347 controls were enrolled. Furthermore, 233 UC and 470 CD trios were included for segregation analysis. Genotyping was performed by application of the TaqMan MGB biallelic discrimination system.

RESULTS

When comparing genotype frequencies of CD and UC patients versus controls, no significant difference was found (p=0.089 and p=0.078, respectively). However, the Cochran-Armitage trend test revealed a rising probability for CD and UC with increasing number of G alleles (p=0.030 and 0.028, respectively) for the case-control analysis. On the contrary, the family-based transmission disequilibrium test (TDT) did not show an association of the G allele with CD or UC in 470 CD and 233 UC trios (p=0.53 and p=0.79, respectively).

CONCLUSION

The -137 (G/C) IL-18 promoter polymorphism is not a susceptibility factor for IBD in a German cohort.

Cytokines and growth factor modulators in intestinal inflammation and repair

Breakdown in gastrointestinal mucosal integrity may be due to increased aggressive factors, including an excessive inflammatory response, decreased mucosal defence or a combination of the two. Our understanding of the control processes underlying these changes has rapidly expanded over the last decade and it is becoming clear that rather than being distinct elements, inflammation and repair are interrelated processes mediated by common cytokines and growth factors, with the division of factors as being a cytokine or a growth factor being somewhat artificial. The use of biological therapies, such as antibodies that cause receptor blockade or administering recombinant growth factors, has now progressed from the laboratory to the clinical arena. This review summarizes current thoughts on the use of these factors in general, but with particular emphasis on inflammatory bowel disease.