Alyssa M. Parian

Compartment-specific immunity in the human gut: properties and functions of dendritic cells in the colon versus the ileum

Objective Dendritic cells (DC) mediate intestinal immune tolerance. Despite striking differences between the colon and the ileum both in function and bacterial load, few studies distinguish between properties of immune cells in these compartments. Furthermore, information of gut DC in humans is scarce. We aimed to characterise human colonic versus ileal DC. Design Human DC from paired colonic and ileal samples were characterised by flow cytometry, electron microscopy or used to stimulate T cell responses in a mixed leucocyte reaction. Results A lower proportion of colonic DC produced pro-inflammatory cytokines (tumour necrosis factor-α and interleukin (IL)-1β) compared with their ileal counterparts and exhibited an enhanced ability to generate CD4+FoxP3+IL-10+ (regulatory) T cells. There were enhanced proportions of CD103+Sirpα− DC in the colon, with increased proportions of CD103+Sirpα+ DC in the ileum. A greater proportion of colonic DC subsets analysed expressed the lymph-node-homing marker CCR7, alongside enhanced endocytic capacity, which was most striking in CD103+Sirpα+ DC. Expression of the inhibitory receptor ILT3 was enhanced on colonic DC. Interestingly, endocytic capacity was associated with CD103+ DC, in particular CD103+Sirpα+ DC. However, expression of ILT3 was associated with CD103− DC. Colonic and ileal DC differentially expressed skin-homing marker CCR4 and small-bowel-homing marker CCR9, respectively, and this corresponded to their ability to imprint these homing markers on T cells. Conclusions The regulatory properties of colonic DC may represent an evolutionary adaptation to the greater bacterial load in the colon. The colon and the ileum should be regarded as separate entities, each comprising DC with distinct roles in mucosal immunity and imprinting.

Short Bowel Syndrome and Intestinal Failure in Crohn's Disease.

Abstract:Crohns disease is a chronic and progressive inflammatory disorder of the gastrointestinal tract. Despite the availability of powerful immunosuppressants, many patients with Crohns disease still require one or more intestinal resections throughout the course of their disease. Multiple resections and a progressive reduction in bowel length can lead to the development of short bowel syndrome, a form of intestinal failure that compromises fluid, electrolyte, and nutrient absorption. The pathophysiology of short bowel syndrome involves a reduction in intestinal surface area, alteration in the enteric hormonal feedback, dysmotility, and related comorbidities. Most patients will initially require parenteral nutrition as a primary or supplemental source of nutrition, although several patients may eventually wean off nutrition support depending on the residual gut anatomy and adherence to medical and nutritional interventions. Available surgical treatments focus on reducing motility, lengthening the native small bowel, or small bowel transplantation. Care of these complex patients with short bowel syndrome requires a multidisciplinary approach of physicians, dietitians, and nurses to provide optimal intestinal rehabilitation, nutritional support, and improvement in quality of life.

Older Age and Steroid Use Are Associated with Increasing Polypharmacy and Potential Medication Interactions Among Patients with Inflammatory Bowel Disease

Background:Comorbidity and polypharmacy, more prevalent among older persons, may impact the treatment of patients with inflammatory bowel disease (IBD). The aims of this study were to assess the frequency of polypharmacy and medication interactions within a cohort of older patients with IBD and describe IBD treatment patterns. Methods:Cohort study of 190 patients with IBD 65 years or older followed at a tertiary IBD referral center from 2006 to 2012. Data collected included demographics, IBD-specific characteristics including disease activity, and comorbidity. Medication histories were extracted from medical records, and data were used to classify polypharmacy, frequency, and severity of potential medication interactions and inappropriate medication use. Results:Older patients with IBD were prescribed an average of 9 routine medications. Severe polypharmacy (≥10 routine medications) was present in 43.2% of studied patients and associated with increasing age, greater comorbidity, and steroid use. Overall, 73.7% of patients had at least 1 potential medication interaction, including 40% of patients with potential IBD medication-associated interactions. Chronic steroids were prescribed to 40% of the older patients including 24% who were in remission or with mild disease activity. Only 39.5% of patients were on immunomodulators and 21.1% on biologics. Approximately, 35% of patients were given at least 1 Beers inappropriate medication and almost 10% were receiving chronic narcotics. Conclusions:Older patients with IBD are at increased risk for severe polypharmacy and potential major medication interactions especially with increasing comorbidity and chronic steroid use. Steroid-maintenance therapies are prevalent among the older patients with IBD with lower utilization of steroid-sparing regimens.

Appendectomy does not decrease the risk of future colectomy in UC: results from a large cohort and meta-analysis.

Objectives Early appendectomy is inversely associated with the development of UC. However, the impact of appendectomy on the clinical course of UC is controversial, generally favouring a milder disease course. We aim to describe the effect appendectomy has on the disease course of UC with focus on the timing of appendectomy in relation to UC diagnosis. Design Using the National Institute of Diabetes and Digestive and Kidney Diseases Inflammatory Bowel Disease Genetics Consortium database of patients with UC, the risk of colectomy was compared between patients who did and did not undergo appendectomy. In addition, we performed a meta-analysis of studies that examined the association between appendectomy and colectomy. Results 2980 patients with UC were initially included. 111 (4.4%) patients with UC had an appendectomy; of which 63 were performed prior to UC diagnosis and 48 after diagnosis. In multivariable analysis, appendectomy performed at any time was an independent risk factor for colectomy (OR 1.9, 95% CI 1.1 to 3.1), with appendectomy performed after UC diagnosis most strongly associated with colectomy (OR 2.2, 95% CI 1.1 to 4.5). An updated meta-analysis showed appendectomy performed either prior to or after UC diagnosis had no effect on colectomy rates. Conclusions Appendectomy performed at any time in relation to UC diagnosis was not associated with a decrease in severity of disease. In fact, appendectomy after UC diagnosis may be associated with a higher risk of colectomy. These findings question the proposed use of appendectomy as treatment for UC.

Oral Diets and Nutrition Support for Inflammatory Bowel Disease: What Is the Evidence?

Inflammatory bowel disease (IBD), which primarily includes Crohns disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract. The mechanisms of IBD pathogenesis are not well understood at this time, but likely involve an interaction between genetic, gut microbial, immune, and environmental factors. Emerging epidemiologic studies have suggested a relationship between specific dietary nutrients as an environmental factor and IBD risk. Clinical trials have also shown oral diets to have variable efficacy in affecting clinical outcomes for IBD. This review discusses the key studies that evaluated the use of various oral diets as well as nutrition support in the management of IBD.

Who and how to screen for cancer in at-risk inflammatory bowel disease patients

Inflammatory bowel diseases (IBDs) include both Crohn’s disease and ulcerative colitis and both diseases are marked by inflammation within the gastrointestinal tract. Due to long-standing inflammation, IBD patients are at increased risk of colorectal cancer, especially patients with chronic inflammation, pancolitis, co-diagnosis of primary sclerosing cholangitis and a longer duration of disease. Small bowel inflammation places Crohn’s patients at an increased risk of small bowel cancer. A higher risk of skin cancers, lymphomas and cervical abnormalities is also seen in IBD patients; this is likely related to both disease factors and the presence of immunosuppressive medication. This article reviews which patients are at an increased risk of IBD-associated or IBD treatment-associated cancers, when to begin screening and which screening methods are recommended.

Dietary Supplement Therapies for Inflammatory Bowel Disease: Crohn's Disease and Ulcerative Colitis.

Inflammatory bowel disease (IBD) including ulcerative colitis and Crohns disease are chronic relapsing and remitting chronic diseases for which there is no cure. The treatment of IBD frequently requires immunosuppressive and biologic therapies which carry an increased risk of infections and possible malignancy. There is a continued search for safer and more natural therapies in the treatment of IBD. This review aims to summarize the most current literature on the use of dietary supplements for the treatment of IBD. Specifically, the efficacy and adverse effects of vitamin D, fish oil, probiotics, prebiotics, curcumin, Boswellia serrata, aloe vera and cannabis sativa are reviewed.

Effects of Vedolizumab Therapy on Extraintestinal Manifestations in Inflammatory Bowel Disease

BackgroundApproximately 15–20% of ulcerative colitis patients and 20–40% of those with Crohn’s disease experience extraintestinal manifestations (EIMs) of their inflammatory bowel disease (IBD). Clinicians who treat IBD must manage EIMs affecting multiple organs that variably correlate with intestinal disease activity. Vedolizumab is a monoclonal antibody for the treatment of IBD with a gut-selective mechanism of action.AimsThis report evaluates whether vedolizumab is an effective treatment of EIMs, given its gut-specific mechanism of action.MethodsWe report 8 case studies of patients with various EIMs, including pyoderma gangrenosum, peripheral arthralgia/arthritis, axial arthropathies, erythema nodosum, and uveitis, who received vedolizumab therapy.ResultsVedolizumab therapy was effective for pyoderma gangrenosum in ulcerative colitis, uveitis, erythema nodosum, polyarticular arthropathy, and ankylosing spondylitis/sacroiliitis but did not provide sustained benefit for the treatment of pyoderma gangrenosum in a patient with Crohn’s disease.ConclusionsThese cases demonstrate the potential of vedolizumab as a treatment of EIMs in patients with IBD.

Role of Vitamin D in Inflammatory Bowel Disease

Vitamin D is a secosteroid hormone that possesses immunomodulatory properties and has been demonstrated to potentially influence inflammatory bowel disease (IBD) pathogenesis and activity. Epidemiologic data have associated vitamin D deficiency with an increased risk of IBD, hospitalizations, surgery, and loss of response to biologic therapy. Conversely, IBD itself can lead to vitamin D deficiency. This bidirectional relationship between vitamin D and IBD suggests the need for monitoring and repletion of vitamin D, as needed, in the IBD patient. This review discusses the role of vitamin D in IBD and provides practical guidance on vitamin D repletion.

Smoking and Inflammatory Bowel Disease: A Comparison of China, India, and the USA

AbstractBackgroundCigarette smoking is thought to increase the risk of Crohn’s disease (CD) and exacerbate the disease course, with opposite roles in ulcerative colitis (UC). However, these findings are from Western populations, and the association between smoking and inflammatory bowel disease (IBD) has not been well studied in Asia. AimsWe aimed to compare the prevalence of smoking at diagnosis between IBD cases and controls recruited in China, India, and the USA, and to investigate the impact of smoking on disease outcomes.MethodsWe recruited IBD cases and controls between 2014 and 2018. All participants completed a questionnaire about demographic characteristics, environmental risk factors and IBD history.ResultsWe recruited 337 participants from China, 194 from India, and 645 from the USA. In China, CD cases were less likely than controls to be current smokers (adjusted odds ratio [95% CI] 0.4 [0.2–0.9]). There was no association between current or former smoking and CD in the USA. In China and the USA, UC cases were more likely to be former smokers than controls (China 14.6 [3.3–64.8]; USA 1.8 [1.0–3.3]). In India, both CD and UC had similar current smoking status to controls at diagnosis. Current smoking at diagnosis was significantly associated with greater use of immunosuppressants (4.4 [1.1–18.1]) in CD cases in China.ConclusionsWe found heterogeneity in the associations of smoking and IBD risk and outcomes between China, India, and the USA. Further study with more adequate sample size and more uniform definition of smoking status is warranted.