Mesalamine in Pediatric Inflammatory Bowel Disease: A 10-Year Experience:

Obesity and the microbiome in atopic dermatitis: Therapeutic implications for PPAR-γ agonists

Atopic dermatitis (AD) is an inflammatory skin disease characterized by epidermal barrier disruption, Th2 immune responses to skin allergens and microbial dysbiosis within affected lesions. Studies within the past decade have revealed genetic and environmental factors contributing to AD in children. Obesity is a metabolic disorder that often manifests early in life and is associated with reduced bacterial diversity, leading to skin colonization with lipophilic bacteria and intestinal colonization with pro-inflammatory species. These changes impair epithelial barriers and promote Th17 responses, which may worsen the severity of AD symptoms. While few studies have examined the contribution of microbiota in obesity-induced allergies, there is emerging evidence that PPAR-γ may be an effective therapeutic target. This review discusses the microbiome in pediatric AD, treatment with probiotics, how disease is altered by obesity and potential therapeutic effects of PPAR-γ agonists. While healthy skin contains diverse species adapted for specific niches, lesional skin is highly colonized with Staphylococcus aureus which perpetuates the inflammatory reaction. Treatments for AD should help to restore microbial diversity in the skin and intestine, as well as epithelial barrier function. Pre-clinical models have shown that PPAR-γ agonists can suppress Th17 responses, IgE production and mast cell function, while improving the epidermal barrier and microbial homeostasis. Overall, PPAR-γ agonists may be effective in a subset of patients with AD, and future studies should distinguish their metabolic and anti-inflammatory effects in order to inform the best therapies.

Hepatic Issues and Complications Associated With Inflammatory Bowel Disease: A Clinical Report From the NASPGHAN Inflammatory Bowel Disease and Hepatology Committees

Hepatobiliary disorders are common in patients with inflammatory bowel disease (IBD), and persistent abnormal liver function tests are found in approximately 20% to 30% of individuals with IBD. In most cases, the cause of these elevations will fall into 1 of 3 main categories. They can be as a result of extraintestinal manifestations of the disease process, related to medication toxicity, or the result of an underlying primary hepatic disorder unrelated to IBD. This latter possibility is beyond the scope of this review article, but does need to be considered in anyone with elevated liver function tests. This review is provided as a clinical summary of some of the major hepatic issues that may occur in patients with IBD.

Infliximab for the treatment of pediatric ulcerative colitis

Ulcerative colitis is a chronic, idiopathic, inflammatory disease of the colon and rectum that may be associated with growth failure, nutritional derangements and psychosocial ramifications in affected children. Multiple medical options are available to achieve disease remission; however, some of these medications can have unwanted side effects, especially in younger patients. With increased understanding of the etiology of the disease, newer therapeutic alternatives have arisen in the form of biologic therapies, namely monoclonal antibodies targeted to a specific protein or receptor. Specifically, infliximab, an anti-TNF-α agent, has been shown to be safe and effective for the treatment of moderate-to-severe pediatric ulcerative colitis.

The genetics of inflammatory bowel disease: diagnostic and therapeutic implications

BACKGROUND

The genetics of inflammatory bowel diseases (IBD) has brought new insight into the spectrum of disease phenotypes that are collectively labeled as either Crohn's disease or ulcerative colitis. In concert with the pharmacogenomics of drug therapy, it has led clinicians to develop the notion of a more tailored approach to therapy.

DATA SOURCES

Articles were searched from PubMed (1995-2010) with key words "inflammatory bowel diseases", "Genetics", "pharmacogenomics".

RESULTS

Among all the putative susceptibility loci, the NOD2 gene has been the most studied and linked to an aggressive form of stricturing and perforating disease of the ileum. Other potential gene polymorphisms, including those encoding for the interleukin-23 receptor, have lent themselves to the recent development of potential novel immunosuppressive therapies. While the linkage of a number of autophagy genes with either Crohn's disease or ulcerative colitis has provided insight into the innate adaptive immune pathway's response to commensual intestinal bacteria. Pharmacogenetic polymorphisms of azathioprine metabolism have been shown to predict toxicity to anti-metabolite therapy. Patients with absent thiopurine methyl transferase enzyme activity are at risk for irreversible bone marrow suppression, and are not considered good candidates for either 6-mercaptopurine (6-MP) or azathioprine therapy.

CONCLUSIONS

Ultimately, the correlation between these genotypes and clinical phenotype of disease will inevitably lead to an improved understanding of disease natural history and a more tailored approach to therapy. Although there is ongoing debate as to whether these inherent differences in enzyme activity can predict responsiveness to anti-metabolite therapy, some gastroenterologists do find value in 6-MP metabolite testing as a means of monitoring patient compliance and tailoring the dose of anti-metabolite therapy based on a perceived therapeutic window. In the future, patients with IBD will ultimately be categorized based on their genomic imprint to allow for a better delineation of disease phenotype. Furthermore, the application pharmacogenomics of drug therapy into clinical practice will be pivotal in maximizing treatment response while avoiding untoward side-effects.

Systematic review of the evidence base for the medical treatment of paediatric inflammatory bowel disease

OBJECTIVE

To systematically review the evidence base for the medical (pharmaceutical and nutritional) treatment of paediatric inflammatory bowel disease.

METHODS

Key clinical questions were formulated regarding different treatment modalities used in the treatment of paediatric (not adult-onset) IBD, in particular the induction and maintenance of remission in Crohn disease and ulcerative colitis. Electronic searches were performed from January 1966 to December 2006, using the electronic search strategy of the Cochrane IBD group. Details of papers were entered on a dedicated database, reviewed in abstract form, and disseminated in full for appraisal. Clinical guidelines were appraised using the AGREE instrument and all other relevant papers were appraised using Scottish Intercollegiate Guidelines Network methodology, with evidence levels given to all papers.

RESULTS

A total of 6285 papers were identified, of which 1255 involved children; these were entered on the database. After critical appraisal, only 103 publications met our criteria as evidence on medical treatment of paediatric IBD. We identified 3 clinical guidelines, 1 systematic review, and 16 randomised controlled trials; all were of variable quality, with none getting the highest methodological scores.

CONCLUSIONS

This is the first comprehensive review of the evidence base for the treatment of paediatric IBD, highlighting the paucity of trials of high methodological quality. As a result, the development of clinical guidelines for managing children and young people with IBD must be consensus based, informed by the best-available evidence from the paediatric literature and high-quality data from the adult IBD literature, together with the clinical expertise and multidisciplinary experience of paediatric IBD experts.

Current therapy of inflammatory bowel disease in children

Ulcerative colitis (UC) and Crohn disease (CD) are chronic intestinal inflammatory diseases that can present as bloody diarrhea, abdominal pain, and malnutrition. Collectively, these disorders are referred to as inflammatory bowel disease (IBD). All patients with IBD share a common pathophysiology. However, there are a number of developmental, psychosocial, and physiologic issues that are unique to the approximate, equals 20% of patients that present during childhood or adolescence. These include the possibility of disease-induced delays in linear growth or physical development, differences in drug dosing, and the changes in social and cognitive development that occur as children move from school-age years into adolescence and early adulthood. Gastroenterologists caring for these children must therefore develop an optimal regimen of pharmacologic therapies, nutritional management, psychologic support, and properly timed surgery (when necessary) that will maintain disease remission, minimize disease and drug-induced adverse effects, and optimize growth and development. This article reviews current approaches to the management of patients with UC and CD and highlights issues specific to the treatment of children with IBD. The principal medical therapies used to induce disease remission in patients with UC are aminosalicylates (for mild disease), corticosteroids (for moderate disease), and cyclosporine (ciclosporin) (for severe disease). If a patient responds to the induction regimen, maintenance therapies that are used to prevent disease relapse include aminosalicylates, mercaptopurine, and azathioprine. Colectomy with creation of an ileal pouch anal anastomosis (J pouch) has become the standard of care for patients with severe or refractory colitis and results in an improved quality of life in most patients. Therefore, the risks associated with using increasingly potent immunosuppressant agents must be balanced in each case against a patient's desire to retain their colon and avoid a temporary or potentially permanent ileostomy. Decisions about drug therapy in the management of patients with CD are more complex and depend on both the location (e.g. gastroduodenal vs small intestinal vs colonic), as well as the behavior of the disease (inflammatory/mucosal vs stricturing vs perforating) in a given patient. Induction therapies for CD typically include aminosalicylates and antibiotics (for mild mucosal disease), nutritional therapy (including elemental or polymeric formulas), corticosteroids (for moderate disease), and infliximab (for corticosteroid-resistant or fistulizing disease). Aminosalicylates, mercaptopurine, azathioprine, methotrexate, and infliximab can be used as maintenance therapies. Because surgical treatment of CD is not curative, it is typically reserved for those patients either with persistent symptoms and disease limited to a small section of the intestine (e.g. the terminal ileum and cecum) or for the management of complications of the disease including stricture or abdominal abscess. When surgery is necessary, maintenance medications administered postoperatively will postpone recurrence. Patients with UC and CD are at risk for the development of micronutrient deficiencies (including folate, iron, and vitamin D deficiencies) and require close nutritional monitoring. In addition, patients with UC and CD involving the colon are at increased risk of developing colon cancer, and should be enrolled into a colonoscopy surveillance program after 8-10 years of disease duration.

Pharmacokinetics of mesalazine pellets in children with inflammatory bowel disease

Mesalazine is a first-line drug in pediatric inflammatory bowel disease (IBD), and is customarily used to induce and maintain remission in mild to moderate disease. In children, pharmacokinetic data are scarce, and dosage recommendations are largely extrapolated from studies in adults. Aim of the study was to obtain the pharmacokinetic profile of a new mesalazine pellet formulation in children with ulcerative colitis and Crohn's colitis. A single oral dose of 20 mg/kg mesalazine was administered to 13 patients (age 6-16 years). Serial blood and urine sampling for determination of mesalazine and acetylmesalazine was performed before and during 24 hours following ingestion. Maximum plasma concentration of mesalazine (Cmax) was 1332 ng/mL (geometric mean, geometric coefficient of variation [CV]: 0.57), obtained 3.7 hours (tmax; CV: 0.31) after drug administration. Systemic exposure as determined by area under the plasma concentration-time curve (AUC(0-infinity) ) was 8712 ng/ml*h (CV: 0.44). Terminal half-life of elimination of mesalazine was 3.5 hours (t(1/2); CV: 1.43). This study presents extensive pharmacokinetic data on mesalazine in children with mild-moderately active ulcerative colitis and Crohn's colitis. In comparison with previous experience in adults, pharmacokinetics of mesalazine administered as pellets appear to be similar in both populations.