Mucosal Gene Expression in Pediatric and Adult Patients With Ulcerative Colitis Permits Modeling of Ideal Biopsy Collection Strategy for Transcriptomic Analysis.

Background: Transcriptional profiling has been performed on biopsies from ulcerative colitis patients. Limitations in prior studies include the variability introduced by inflammation, anatomic site of biopsy, extent of disease, and medications. We sought to more globally understand the variability of gene expression from patients with ulcerative colitis to advance our understanding of its pathogenesis and to guide clinical study design. Methods: We performed transcriptional profiling on 13 subjects, including pediatric and adult patients from 2 hospital sites. For each patient, we collected 6 biopsies from macroscopically inflamed tissue and 4 biopsies from macroscopically healthy-appearing tissue. Isolated RNA was used for microarray gene expression analysis utilizing Affymetrix Human Primeview microarrays. Ingenuity pathway analysis was used to assess over-representation of gene ontology and biological pathways. RNAseq was also performed, and differential analysis was assessed to compare affected vs unaffected samples. Finally, we modeled the minimum number of biopsies required to reliably detect gene expression across different subject numbers. Results: Transcriptional profiles co-clustered independently of the hospital collection site, patient age, sex, and colonic location, which parallels prior gene expression findings. A small set of genes not previously described was identified. Our modeling analysis reveals the number of biopsies and patients per cohort to yield reliable results in clinical studies. Conclusions: Key findings include concordance, including some expansion, of previously published gene expression studies and similarity among different age groups. We also established a reliable statistical model for biopsy collection for future clinical studies.

Sequential Combination Therapy Versus Monotherapy: A Lack of Benefit in Time to Inflammatory Bowel Disease-Related Surgery.

BACKGROUND: The benefits of combination therapy with infliximab and azathioprine have been demonstrated in clinical trials of patients with ulcerative colitis (UC) and Crohn's disease (CD). Concerns remain regarding the ideal duration and benefits of adding therapies in a sequential manner. AIMS: We aim to compare long-term outcomes among patients with inflammatory bowel disease (IBD) treated with sequentially added combination therapy or monotherapy strategies . METHODS: We performed a retrospective cohort study involving adult patients with UC and CD. One cohort included patients treated with infliximab, adalimumab, or a thiopurine as monotherapy. A second cohort included patients treated with sequentially added combination therapy including infliximab or adalimumab and a thiopurine. The primary outcome was the rate of IBD-related surgery. RESULTS: Among 462 patients, 181 (39 %) were treated with combination therapy. 12 % of patients treated with combination therapy underwent an IBD-related surgery compared to 18 % of patients treated with monotherapy (p = 0.091), with no overall difference in time to IBD-related surgery demonstrated (log-rank test, p = 0.063). When evaluating the subtypes of IBD, there was a significant benefit in time to IBD-related surgery among patients with CD treated with sequentially added combination therapy (HR 0.46, 95 % CI 0.25-0.85) but not UC (HR 0.82, 95 % CI 0.30-2.22). CONCLUSIONS: The benefits of sequentially added combination therapy seem blunted when evaluating long-term clinical outcomes. This may be due to a decreased effectiveness of sequential combination therapy, a loss of benefit over time, or a differential effect between subtypes of IBD.

An inflammation-targeting hydrogel for local drug delivery in inflammatory bowel disease.

There is a clinical need for new, more effective treatments for chronic and debilitating inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Targeting drugs selectively to the inflamed intestine may improve therapeutic outcomes and minimize systemic toxicity. We report the development of an inflammation-targeting hydrogel (IT-hydrogel) that acts as a drug delivery system to the inflamed colon. Hydrogel microfibers were generated from ascorbyl palmitate, an amphiphile that is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration. IT-hydrogel microfibers loaded with the anti-inflammatory corticosteroid dexamethasone (Dex) were stable, released drug only upon enzymatic digestion, and demonstrated preferential adhesion to inflamed epithelial surfaces in vitro and in two mouse colitis models in vivo. Dex-loaded IT-hydrogel enemas, but not free Dex enemas, administered every other day to mice with colitis resulted in a significant reduction in inflammation and were associated with lower Dex peak serum concentrations and, thus, less systemic drug exposure. Ex vivo analysis of colon tissue samples from patients with ulcerative colitis demonstrated that IT-hydrogel microfibers adhered preferentially to mucosa from inflamed lesions compared with histologically normal sites. The IT-hydrogel drug delivery platform represents a promising approach for targeted enema-based therapies in patients with colonic IBD.