Christian D. Stone

A key role for autophagy and the autophagy gene Atg16l1 in mouse and human intestinal Paneth cells

Susceptibility to Crohn’s disease, a complex inflammatory disease involving the small intestine, is controlled by over 30 loci. One Crohn’s disease risk allele is in ATG16L1, a gene homologous to the essential yeast autophagy gene ATG16 (ref. 2). It is not known how ATG16L1 or autophagy contributes to intestinal biology or Crohn’s disease pathogenesis. To address these questions, we generated and characterized mice that are hypomorphic for ATG16L1 protein expression, and validated conclusions on the basis of studies in these mice by analysing intestinal tissues that we collected from Crohn’s disease patients carrying the Crohn’s disease risk allele of ATG16L1. Here we show that ATG16L1 is a bona fide autophagy protein. Within the ileal epithelium, both ATG16L1 and a second essential autophagy protein ATG5 are selectively important for the biology of the Paneth cell, a specialized epithelial cell that functions in part by secretion of granule contents containing antimicrobial peptides and other proteins that alter the intestinal environment. ATG16L1- and ATG5-deficient Paneth cells exhibited notable abnormalities in the granule exocytosis pathway. In addition, transcriptional analysis revealed an unexpected gain of function specific to ATG16L1-deficient Paneth cells including increased expression of genes involved in peroxisome proliferator-activated receptor (PPAR) signalling and lipid metabolism, of acute phase reactants and of two adipocytokines, leptin and adiponectin, known to directly influence intestinal injury responses. Importantly, Crohn’s disease patients homozygous for the ATG16L1 Crohn’s disease risk allele displayed Paneth cell granule abnormalities similar to those observed in autophagy-protein-deficient mice and expressed increased levels of leptin protein. Thus, ATG16L1, and probably the process of autophagy, have a role within the intestinal epithelium of mice and Crohn’s disease patients by selective effects on the cell biology and specialized regulatory properties of Paneth cells.

Risk of arterial thrombotic events in inflammatory bowel disease.

OBJECTIVES:Patients with inflammatory bowel disease (IBD) have an increased risk of venous thrombotic events. The risk of arterial thrombotic events in IBD, however, has been less well characterized. We explored whether Crohns disease (CD) and ulcerative colitis (UC) are associated with a higher risk for thrombotic events involving the mesenteric, cardiac, or cerebral arteries.METHODS:Using the Thomson Reuters MarketScan Research claims database, we conducted a retrospective cohort study of IBD patients observed for the occurrence of pre-defined thrombotic events. For comparison, four non-IBD controls were age-, sex-, and index date–matched to each IBD case. The outcomes of interest were acute mesenteric ischemia, transient ischemic attack, cerebrovascular occlusion, atherosclerosis, peripheral vascular disease, and myocardial infarction. We performed a multivariate analysis adjusting for potential confounders for thrombotic events, including hypertension, diabetes, hyperlipidemia, and, in women, the use of contraceptives. We calculated the adjusted hazard ratios (HRs) for each event by comparing IBD patients with controls and used the log-rank test to determine statistical significance.RESULTS:The study included 17,487 IBD patients and 69,948 controls. Overall, IBD patients had a markedly increased risk of acute mesenteric ischemia (HR=11.2, P<0.001). IBD patients as a whole did not have an increased risk of other arterial thrombotic events, including myocardial infarction and transient ischemic attack, when compared with controls. However, women with IBD who were over the age of 40 years had a higher risk of myocardial infarction (HR=1.6, P=0.003). In addition, women with IBD below the age of 40 years who showed a significantly higher risk for stroke (HR=2.1, P=0.04). For all events, the risks in CD and UC were similar.CONCLUSIONS:Patients with IBD have a markedly increased risk of acute mesenteric ischemia. Subgroup analysis reveals that women over the age of 40 years with IBD are at increased risk of myocardial infarction, whereas those below the age of 40 years exhibit a two-fold higher risk for stroke. In contrast, men with IBD did not share these same risks for arterial thrombotic events.

Risk Factors for Surgical Recurrence after Ileocolic Resection of Crohn's Disease

PurposeWe evaluated the effect of potential clinical factors on surgical recurrence of ileal Crohn’s disease after initial ileocolic resection.MethodsOne hundred seventy-six patients with ileal Crohn’s disease who underwent an ileocolic resection with anastomosis were identified from our database. The outcome of interest was time from first to second ileocolic resection. Survival analysis was used to assess the significance of the Montreal phenotype classification, smoking habit, a family history of inflammatory bowel disease and other clinical variables.ResultsIn our final Cox model, a family history of inflammatory bowel disease (hazard ratio 2.24, 95 percent confidence interval 1.16–4.30, P = 0.016), smoking at time of initial ileocolic resection (hazard ratio 2.08, 95 percent confidence interval 1.11–3.91, P = 0.023) was associated with an increased risk of a second ileocolic resection while postoperative prescription of immunomodulators (hazard ratio 0.40, 95 percent confidence interval 0.18–0.88, P = 0.022) was associated with a decreased risk of a second ileocolic resection.ConclusionsBoth a family history of inflammatory bowel disease and smoking at the time of the initial ileocolic resection are associated with an increased risk of a second ileocolic resection. Postoperative prescription of immunomodulators is associated with a reduced risk of surgical recurrence. This study supports the concept that both genetic and environmental factors influence the risk of surgical recurrence of ileal Crohn’s disease.

Patients With Late-Adult-Onset Ulcerative Colitis Have Better Outcomes Than Those With Early Onset Disease

BACKGROUND & AIMS The influence of age on the presentation, clinical course, and therapeutic response of patients with adult-onset ulcerative colitis (UC) is understudied. Given potential age-related differences in risk factors and immune function, we sought to determine if disease behavior or clinical outcomes differed between patients diagnosed with UC in later versus earlier stages of adulthood. METHODS We performed a retrospective cohort study of 295 patients with UC seen at a tertiary care center from 2001 to 2008. Adult subjects newly diagnosed with UC between the ages of 18 and 30 years were defined as early onset, those newly diagnosed at age 50 or older were defined as late onset. The 2 groups were analyzed for differences in medication use and clinical end points, including disease extent, severity at the time of diagnosis, and steroid-free clinical remission at 1 year after disease onset. RESULTS Disease extent and symptom severity were similar between groups at the time of diagnosis. One year after diagnosis, more patients in the late-onset group achieved steroid-free clinical remission (64% vs 49%; P = .01). Among those who required systemic steroid therapy, more late-onset patients achieved steroid-free remission by 1 year (50% vs 32%; P = .01). Former smoking status was a more common risk factor in the late-onset cohort (P < .001), whereas more early onset patients had a positive family history (P = .008). CONCLUSIONS Patients with early and late-adult-onset UC have similar initial clinical presentations, but differ in disease risk factors. Late-onset patients have better responses to therapy 1 year after diagnosis.

Reactive hemophagocytic syndrome complicating the treatment of inflammatory bowel disease

Background and Aims: Reactive hemophagocytic syndrome (RHS) is a rare disease in which inappropriately activated macrophages consume bone marrow‐derived cells. Most cases are associated with infection in the setting of immunodeficiency. The widespread use of immunosuppressive therapy in the treatment of inflammatory bowel disease (IBD) places patients with Crohns disease and ulcerative colitis at risk of this complication. No concerted effort has been made to alert gastroenterologists of this condition, and treatment recommendations are lacking. The aims of this study were to describe the clinical and laboratory features of RHS associated with IBD and to review diagnostic criteria, treatment options, and pathogenesis. Materials and Methods: Clinical and laboratory data were pooled from the clinical practice of the investigators and from published cases. Descriptive statistics were performed. Results and Conclusions: Seven cases of RHS complicating the treatment of IBD were identified. All patients were on immunosuppressive therapy, with nearly half taking >1 agent. All patients presented with fever, leukopenia, anemia, and hyperferritinemia. Infection by a member of the herpesvirus family or an intracellular pathogen precipitated RHS in 6 of 7 patients. The mortality rate was 29%. The diagnosis of RHS should be considered in patients with IBD taking immunosuppressive therapy who present with fever and cytopenia. Evaluation should begin with a serum ferritin. In patients with a serum ferritin ≥10,000 ng/mL, a bone marrow biopsy should be performed to confirm hemophagocytosis. If the initial evaluation is negative, then clinical suspicion should be maintained until the episode resolves.

Practice of gastroenterologists in treating flaring inflammatory bowel disease patients with clostridium difficile: antibiotics alone or combined antibiotics/immunomodulators?

Background: The optimal management of Clostridium difficile infection (CDI) in flaring inflammatory bowel disease (IBD) patients has not been defined. Limited data suggest that coadministration of immunomodulators (IM) with antibiotics (AB) results in a worse outcome. We investigated the prevalent practice among North American gastroenterologists in this scenario. Methods: A structured questionnaire presented the clinical cases of two hospitalized patients with ulcerative colitis and concomitant CDI, either with or without prior IM treatment. The questionnaire was distributed to a sample of gastroenterologists at medical centers across North America. Respondents were requested to denote their therapeutic choices for these patients. Results: The survey included 169 gastroenterologists, 122 from the US and 47 from Canada, with an average of 12 ± 10 years of experience in gastroenterology. Forty‐two (25%) of the respondents were IBD experts. Seventy‐seven (46%) respondents elected to add an IM in combination with AB, whereas 82/169 (54%) treated the flare with AB alone (P = NS). The rate of administering combined AB+IM was similar for the IBD experts and the non‐IBD experts. Only 11% of respondents withdrew maintenance azathioprine upon the diagnosis of CDI. More IBD experts stopped azathioprine treatment compared to the non‐IBD experts (12/42 versus 6/127, P < 0.001). Overall, 65% of surveyed gastroenterologists stated they believe these patients are afflicted by two simultaneous but separate disease processes. Conclusions: There is significant disagreement among gastroenterologists on whether combination AB+IM or AB alone should be given to IBD patients with CDI‐associated flares. Controlled trials are needed to investigate the optimal management approach to this clinical dilemma. (Inflamm Bowel Dis 2010;)

NOD2 status and human ileal gene expression.

Background: NOD2 single nucleotide polymorphisms have been associated with increased risk of ileal Crohns disease (CD). This exploratory study was conducted to compare ileal mucosal gene expression in CD patients with and without NOD2 risk alleles. Methods: Ileal samples were prospectively collected from 18 nonsmoking CD patients not treated with anti‐TNF‐&agr; biologics and 9 nonsmoking control patients without inflammatory bowel disease undergoing initial resection and genotyped for the 3 major NOD2 risk alleles (Arg702Trp, Gly908Arg, Leu1007fs). Microarray analysis was performed in samples from 4 NOD2R (at least 1 risk allele) CD patients, 4 NOD2NR (no risk alleles) CD patients, and 4 NOD2NR controls. Candidate genes selected by significance analysis of microarrays (SAM) were confirmed by quantitative reverse transcriptase polymerase chain reaction (qRT‐PCR) assays of all the samples. Results: SAM detected upregulation of 18 genes in affected ileum in NOD2R compared to NOD2NR CD patients, including genes related to lymphocyte activation. SAM also detected altered ileal gene expression in unaffected NOD2NR ileal mucosal CD samples compared to NOD2NR control samples. qRT‐PCR conducted on all the samples confirmed that increased CD3D expression in affected samples was associated with NOD2R status, and that increased MUC1, DUOX2, DMBT1 and decreased C4orf7 expression in unaffected samples was associated with CD, independent of NOD2 status. Conclusions: The results support the concept that NOD2 risk alleles contribute to impaired regulation of inflammation in the ileum. Furthermore, altered ileal gene expression, independent of NOD2 status, is detected in the unaffected proximal margin of resected ileum from CD patients. (Inflamm Bowel Dis 2010)

Celiac Disease Unmasked After Pancreaticoduodenectomy

A report of profound diarrhea, weight loss, and malnutrition secondary to celiac disease that manifested after pancreaticoduodenectomy (Whipple surgery). The patient had no prior diarrhea or other symptoms of celiac disease and the diagnosis was unsuspected for months. A review of this underappreciated presentation of celiac disease is provided.

Combination of corticosteroids and 5-aminosalicylates or corticosteroids alone for patients with moderate-severe active ulcerative colitis: A global survey of physicians' practice

AIM To examine treatment decisions of gastroenterologists regarding the choice of prescribing 5-aminosalycilates (5ASA) with corticosteroids (CS) versus corticosteroids alone for patients with active ulcerative colitis (UC). METHODS A cross-sectional questionnaire exploring physicians’ attitude toward 5ASA + CS combination therapy vs CS alone was developed and validated. The questionnaire was distributed to gastroenterology experts in twelve countries in five continents. Respondents’ agreement with stated treatment choices were assessed by standardized Likert scale. Background professional characteristics of respondents were analyzed for correlation with responses. RESULTS Six hundred and sixty-four questionnaires were distributed and 349 received (52.6% response rate). Of 340 eligible respondents, 221 (65%) would continue 5ASA in a patient hospitalized for intravenous CS treatment due to a moderate-severe UC flare, while 108 (32%) would stop the 5ASA (P < 0.001), and 11 (3%) are undecided. Similarly, 62% would continue 5ASA in an out-patient starting oral CS. However, only 140/340 (41%) would proactively start 5ASA in a hospitalized patient not receiving 5ASA before admission. Most (94%) physicians consider the safety profile of 5ASA as very good. Only 52% consider them inexpensive, 35% perceive them to be expensive and 12% are undecided. On multi-variable analysis, less years of practice and perception of a plausible additive mechanistic effect of 5ASA + CS were positively associated with the decision to continue 5ASA with CS. CONCLUSION Despite the absence of data supporting its benefit, most gastroenterologists endorse combination of 5ASA + CS for patients with active moderate-to-severe UC. Randomized controlled trials are needed to assess if 5ASA confer any benefit for these patients.

More bad news on Clostridium difficile in inflammatory bowel disease

Recently, several reports have documented an alarming rise in the incidence and severity of Clostridium difficile infections, also known as C. difficile-associated disease (CDAD), both in general and in the subpopulation of patients with inflammatory bowel disease (IBD). Observations over the past several years in single-center, tertiary referral centers describe a tripling of the incidence of C. difficile in ulcerative colitis (UC), less so in Crohn’s disease (CD).1,2 This is well above the increases noted in the non-IBD population. The goal of the study by Nguyen et al3 was to expand upon these previous reports by examining the trend of C. difficile infections across a variety of healthcare centers throughout the United States, not just in single center, referral-based hospitals. To do this, they used the Nationwide Inpatient Sample (NIS), an immense database that represents a stratified sampling of 20% of inpatient admissions in the US. They compared temporal patterns between 1998 and 2004 of C. difficile infection between hospitalized IBD patients and non-IBD patients at national and population-based levels, identifying the comparison groups and C. difficile infections by means of ICD-9 coding within the NIS. Their major finding is that, indeed, there is a nationwide, statistically significant rising trend of C. difficile infections in IBD, with the most pronounced increase seen in UC. Furthermore, the authors have shown an association between C. difficile and increased mortality, length of stay (LOS), and hospital charges, but the higher mortality, a nearly 4-fold increase, was observed only in UC and not CD. They examined several factors in a multivariate model to attempt to identify characteristics that might confer a higher risk for CDAD in IBD. They found, for example, a difference in the rates of C. difficile infection depending on the anatomical location of CD: those with colonic CD were diagnosed with CDAD 3.5 times more often than those with only small bowel CD, after adjustment for age, gender, comorbidity, calendar year, and hospital setting. This confirms the previous finding that colonic disease is an independent predictor of C. difficile infection in CD patients.2 Not surprisingly, in the Nguyen et al study IBD patients were more likely to be admitted to teaching hospitals. It was also noted that there was seasonal variation in CDAD in IBD, with 20% higher rates in non-summer months, although the underlying reasons for this remain unclear.