Maintenance therapy for Crohn's disease

Persistent systemic inflammation and atypical enterocolitis in patients with NEMO syndrome

The NEMO syndrome is a primary immunodeficiency with immune and non-immune manifestations. The immune deficiency is heterogeneous showing defects in humoral, innate, and cell-mediated immunity. While the clinical aspects of the immunodeficiency are increasingly well understood, little is known about autoimmune manifestations in NEMO patients. We therefore sought to examine serologic markers of systemic inflammation and intestinal pathology in a kindred of patients with the NEMO syndrome. We observed persistent elevation of erythrocyte sedimentation rates in five patients, and two were symptomatic, with a chronic but atypical enterocolitis. Though pathologic lesions in these two patients were consistent with acute inflammation, sustained clinical improvement was only achieved with systemic and/or topical glucocorticoid therapy. Our data suggest that some patients with the NEMO syndrome exhibit persistent elevation of inflammatory markers similar to systemic autoimmune diseases and may subsequently develop an atypical enterocolitis.

Classification of genetic profiles of Crohn's disease: a focus on the ATG16L1 gene

Inflammatory bowel disease constitutes two related clinical entities, Crohn's disease (CD) and ulcerative colitis (UC), both of which have increased in prevalence over the last decade. Family and twin studies have strongly indicated that genetic factors play a large role in an individual's risk of developing inflammatory bowel disease. Despite this, it has proven difficult to isolate disease genes that confer susceptibility to this disease using classical candidate gene and linkage approaches, with the notable exception of the isolation of the caspase recruitment domain family, member 15 (CARD15) gene. However, over the last 2 years, genome-wide association (GWA) studies have become feasible, where modern high-throughput single nucleotide polymorphism (SNP) genotyping technologies can be applied to large and comprehensively phenotyped patient cohorts. Such approaches have enabled scientists to robustly associate specific variants with many complex diseases, including age-related macular degeneration, Type 2 diabetes, breast cancer and asthma. In the inflammatory bowel disease field, positive associations with CD and UC coming from GWA studies have been reported for an ever increasing number of genes. The most consistently and strongly associated variants have been in the CARD15, the interleukin 23 receptor (IL23R) and autophagy-related 16-like 1 (ATG16L1) genes. With respect to ATG16L1, the G allele of SNP rs2241880 has been shown in multiple association studies to confer strong risk for CD, although its association with UC remains more debatable. This SNP is in fact a common coding variant, specifically a threonine-to-alanine substitution at amino acid position 300 of the ATG16L1 protein (T300A), and appears to account for all of the disease risk conferred by this locus. This review addresses recent advances in GWA studies of inflammatory bowel disease, with specific focus on the growing evidence of the ATG16L1 gene's role in CD and how its protein product operating within the autophagic pathway makes autophagy an attractive therapeutic target for this debilitating disorder.

Pediatric inflammatory bowel disease: clinical and molecular genetics

Pediatric-onset inflammatory bowel disease (IBD) is characterized by distinct phenotypic differences compared to adult-onset IBD. This raises the question whether early (pediatric) onset IBD represents the same disease process occurring in adults but merely at an earlier age or does IBD in children have a very different etiology and pathogenesis but with the same clinical presentation as adults. The use of techniques such as whole genome association studies to perform broad, unbiased screening for the contributions of common genetic variations to complex disease has rapidly assisted in the identification of several novel susceptibility loci associated with pediatric-onset Crohn's disease such as IL23R and ATG16L1. These genes join the already confirmed IBD susceptibility genes such as NOD2/CARD15, IBD5, and DLG5. Therefore, there is hope that advances in the field of clinical and molecular genetics will assist in answering the fundamental question of whether pediatric IBD has a different etiology and pathogenesis compared to adult IBD. This review examines the current status of clinical and molecular genetics of pediatric IBD, and highlights the differences between pediatric and adult IBD in disease phenotypes and genotypes. Finally, the future directions of genetic investigations in pediatric IBD are discussed.

Does the initial location of Crohn's disease have an influence on the time-to-relapse in patients under maintenance treatment with oral mesalamine?

The aim of this study was to determine the possible influence of the initial location of Crohn's disease (CD) on the time-to-relapse in patients with quiescent CD treated only with oral mesalamine (5-ASA). We divided 74 consecutive patients in clinical remission into three groups according to the initial location of CD. Group A consisted of 30 cases with an ileal location; group B, 18 with ileocolonic location; and group C, 26 with a colonic location. The patients entered the study if they were in clinical and endoscopic remission for at least 3 months. Relapse was defined by CD Activity Index > or = 150, CD Endoscopic Index of Severity > or =4, and by an abnormal increase of C-reactive protein, white blood cell count, and erythrocyte sedimentation rate; moreover, if it was confirmed by x-ray and/or endoscopy. Time-to-relapse was defined as the interval between the date of enrollment and the date of relapse. The patients with an ileal location showed a relapse within 5 years, with a time-to-relapse of 1 year in 26% of cases, 2 years in 85%, 3 years in 92%, and 4 years in 96%. The patients with ileocolonic location showed a relapse within 4 years, with time-to-relapse of 1 year in 39% of cases, 2 years in 89%, and 3 years in 94%. The cases with a colonic location showed a relapse within 6 years, with time-to-relapse of 1 year in 33% of cases, 2 years in 71%, 3 years in 79%, and 4 years in 87%. Surgical treatment was necessary in 37% of the cases with an ileal location, in 44% with ileocolonic location, and 17% with a colonic location. In conclusion, even if our data lack a statistical significance, we have found that the initial anatomic involvement is not a valid parameter to predict the relapse risk in a homogeneous group under continuous treatment with oral 5-ASA, although ileocolonic location seems to have a more aggressive course.

[Significance of galenic preparations for luminal release of 5-aminosalicylic acid in human small intestinal lumen]

BACKGROUND

Sufficient intraluminal concentrations of 5-aminosalicylic acid (ASA) within inflamed regions of the intestine are required for therapeutic efficacy in inflammatory bowel disease. Various oral delayed release preparations have been developed to ensure that 5-ASA is set free in those parts of the gut, which are most frequently affected. However, resulting intraluminal concentrations within the small bowel are unknown. Therefore, we determined and compared 5-ASA release within different segments of the small bowel from an Eudragit L coated 5-ASA preparation (Salofalk) and from an ethylcellulose coated microsphere preparation (Pentasa).

METHODS

Twelve healthy subjects were intubated with an oro-ileal multilumen-tube for marker perfusion, duodenal, jejunal and ileal aspiration of chyme and intestinal manometry. Each subject received 500 mg 5-ASA (Salofalk, n = 6, or Pentasa, n = 6) together with a semiliquid test meal. Intestinal aspirates, blood and urine samples were obtained in regular intervals for 7 to 10 hours and were analysed for 5-ASA and its main metabolite acetyl-5-ASA by HPLC.

RESULTS

With Salofalk, gastric emptying of 5-ASA did not take place in the digestive, but in the subsequent interdigestive period. Luminal delivery of 5-ASA and acetyl-5-ASA increased from the duodenum (3% of dose) to the ileum (30% of dose). 10% of the dose administered were excreted in urine and about 90% reached the colon unreleased or solubilised. By contrast, with Pentasa, 5-ASA was delivered to the duodenum together with the test meal and released continuously throughout the small intestine (about 20% of dose solubilised at each intestinal site). Only 3.5% of the dose administered were excreted in urine. Deliver of 5-ASA to the colon was equal to Salofalk.

CONCLUSIONS

From both preparations, considerable amounts of 5-ASA are released during small intestinal transit thus explaining therapeutic efficacy in small intestinal Crohn's disease. Because of specific release patterns, Salofalk may be of use especially in terminal ileal disease, where as patients with extensive small intestinal disease including the proximal small intestine might benefit from Pentasa.

Oral budesonide as maintenance therapy in Crohn's disease--results of a 12-month study. Global Budesonide Study Group

BACKGROUND

Budesonide is a corticosteroid with high topical anti-inflammatory activity and low systemic activity due to rapid inactivation. We have assessed the efficacy and safety of an oral controlled ileal release (CIR) preparation of budesonide for maintenance of remission in patients with ileal or ileocaecal Crohn's disease.

METHODS

In a double-blind, multicentre trial, 75 patients in clinical remission (Crohn's Disease Activity Index, CDAI, < or = 150) were randomly assigned to receive placebo, budesonide 3 mg or budesonide 6 mg daily for 12 months. Trial drugs were given at a fixed dose and without concomitant medication. The primary outcome measure was relapse, defined as a CDAI > 150 together with an increase of at least 60 units from entry. A patient was also considered to have a relapse if withdrawn from the study due to clinical deterioration, whether or not a CDAI value could be calculated at that time.

RESULTS

There were no statistically significant differences in the relapse rate at any time-point throughout the study. By 12 months the proportion of patients having relapsed were 48, 46 and 60% in those patients treated with budesonide 6 mg, 3 mg and placebo, respectively (N.S.). Treatments were well tolerated, and the proportion of patients with suppressed adrenal function (according to predetermined criteria) were 50% (6 mg), 26% (3 mg) and 17% (placebo) (P = 0.096).

CONCLUSIONS

In the present study, relapse rate and time to relapse were similar in the patients treated with budesonide CIR, 6 mg daily or 3 mg daily or with placebo, throughout 12 months. This is in contrast to the two previous trials with identical design, where a significant effect of budesonide CIR in prolonging the median time to relapse was found. Possible reasons for the negative results of the present study include small sample size, and the fact that there was a high placebo response.