Simon Lal

Expression of cannabinoid CB1 receptors by vagal afferent neurons is inhibited by cholecystokinin

Both inhibitory (satiety) and stimulatory (orexigenic) factors from the gastrointestinal tract regulate food intake. In the case of the satiety hormone cholecystokinin (CCK), these effects are mediated via vagal afferent neurons. We now report that vagal afferent neurons expressing the CCK-1 receptor also express cannabinoid CB1 receptors. Retrograde tracing established that these neurons project to the stomach and duodenum. The expression of CB1 receptors determined by RT-PCR, immunohistochemistry and in situ hybridization in rat nodose ganglia was increased by withdrawal of food for ≥12 hr. After refeeding of fasted rats there was a rapid loss of CB1 receptor expression identified by immunohistochemistry and in situ hybridization. These effects were blocked by administration of the CCK-1 receptor antagonist lorglumide and mimicked by administration of CCK to fasted rats. Because CCK is a satiety factor that acts via the vagus nerve and CB1 agonists stimulate food intake, the data suggest a new mechanism modulating the effect on food intake of satiety signals from the gastrointestinal tract.

Modifiable factors associated with nonadherence to maintenance medication for inflammatory bowel disease.

Background: Poor adherence frequently impaired the efficacy of therapy to maintain remission from inflammatory bowel diseases (IBD). There is a lack of practical and effective interventions to improve adherence. This study aimed to identify modifiable risk factors, which may yield targets for new interventions. Methods: Participants with IBD were recruited from hospital outpatient clinics and office-based gastroenterologists. Demographic and disease-related data were recorded by means of self-administered questionnaires. Modifiable risk factors were assessed with the validated Belief about Medicine Questionnaire, Hospital Anxiety and Depression Score, and short inflammatory bowel disease questionnaire. Adherence was assessed separately for 5-aminosalicylates, thiopurines, and biological agents using the validated Medicine Adherence Report Scale (good adherence defined as >16). Results: Nonadherence occurred in 102 of 356 participants (28.7%). Adherence increased significantly with more aggressive therapies (median Medicine Adherence Report Scale: 5-aminosalicylates 18, thiopurines 19, biological 20; P < 0.0001). Nonadherence was not associated with anxiety and depression or disease-related patient knowledge. Adherent patients had significantly higher belief of necessity for medication (P < 0.0001) and a trend toward lower concerns about medication (P = 0.08). Membership of an IBD patient organization was associated with better adherence (P < 0.0001). Concerns about medication rose significantly with more aggressive therapies (P = 0.009), but belief of necessity was similar for all medications. Conclusions: Nonadherence occurs most frequently with 5-aminosalicylates. Belief of necessity may prove the key target for future interventions, although general IBD education is unlikely to yield an adherence benefit. Patient organization membership should be encouraged.

Defining the role of cholecystokinin in the lipid-induced human brain activation matrix.

BACKGROUND & AIMS In human beings, as in most vertebrates, the release of the intestinal peptide cholecystokinin (CCK) by ingested food plays a major role both in digestion and the regulation of further food intake, but the changes in brain function and their underlying activation mechanisms remain unknown. Our aim was to explore, using a novel physiologic magnetic resonance imaging approach, the temporospatial brain activation matrix, in response to ingestion of a lipid meal and, by use of a CCK-1 receptor antagonist, to define the role of CCK in this activation. METHODS We studied, in 19 healthy subjects, the brain activation responses to ingested lipid (dodecanoic acid) or saline (control) with magnetic resonance imaging. Gallbladder volume, plasma CCK levels, and subjective hunger and fullness scores were also recorded. The experiment was then repeated, with and without prior administration of the CCK-1 receptor antagonist dexloxiglumide (600 mg orally) with a controlled, randomized order, latin-square design. RESULTS Ingested lipid activated bilaterally a matrix of brain areas, particularly the brain stem, pons, hypothalamus, and also cerebellum and motor cortical areas. These activations were abolished by dexloxiglumide, indicating a CCK-mediated pathway, independent of any nutrient-associated awareness cues. CONCLUSION The identification of these activations now defines the lipid-activated brain matrix and provides a means by which the gut-derived homeostatic mechanisms of food regulation can be distinguished from secondary sensory and hedonic cues, thereby providing a new approach to exploring aberrant human gastrointestinal responses and eating behavior.

Nutritional management of Crohn's disease.

Nutritional care and therapy forms an integral part of the management of patients with Crohn’s disease (CD). Nutritional deficiencies result from reduced oral intake, malabsorption, medication side effects and systemic inflammation due to active disease. Enteral nutrition has a role in support for the malnourished patient, as well as in primary therapy to induce and maintain remission. The use of parenteral nutrition in CD is mainly limited to the preoperative setting or for patients with intestinal failure, but does not offer any additional advantage over EN in disease control. Dietary modifications, including elimination–reintroduction diets and a low fermentable, oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet may improve symptoms but there are currently no data to suggest that these approaches have any role in the induction or maintenance of remission.

Patients' knowledge of pregnancy‐related issues in inflammatory bowel disease and validation of a novel assessment tool (‘CCPKnow’)

Inflammatory bowel diseases (IBD) require complex therapeutic decisions and life choices concerning pregnancy, but little is known about patients knowledge of IBD and its treatment before and during pregnancy.

Better disease specific patient knowledge is associated with greater anxiety in Inflammatory Bowel Disease

BACKGROUND Inflammatory bowel disease (IBD)-related knowledge not only empowers patients, but may also engender anxiety. The study aimed to identify predictors of anxiety in IBD and examine the interplay between anxiety and disease-related patient knowledge. The effect of anxiety on quality of life was also explored. METHODS Ambulatory IBD patients provided data on demographics, their IBD and Crohns Colitis Association (CCA) membership status. Disease-related knowledge was assessed using the validated Crohns and Colitis Knowledge score (CCKnow) and disease related QOL using the short IBD questionnaire (SIBDQ). Anxiety and depression were assessed with the Hospital Anxiety and Depression Scores. RESULTS Of the 258 patients 19.4% had a potential anxiety and a further 22.4% had a probable anxiety disorder. Females (P=0.003), tertiary care patients (P=0.014) and non-Caucasian patients (P=0.037) had significantly higher anxiety levels. CCA members had marginally higher levels of anxiety (P=0.07). Anxiety was associated with significantly better patient knowledge (P=0.016) and increased depression (P<0.001). Disease related quality of life was significantly lower in patients with anxiety (P<0.001). CONCLUSIONS This is the first study to demonstrate that better patient knowledge is associated with higher anxiety levels. The reason for this is unclear: educating patients about their disease might trigger anxiety, but, equally, anxious patients might seek out information and hence have better knowledge. It is thus noteworthy that an educational intervention may not necessarily reduce anxiety. Further work is needed to evaluate the association between anxiety and knowledge and to develop targeted interventions that will improve knowledge and simultaneously reduce anxiety.

Central Venous Catheter Salvage in Home Parenteral Nutrition Catheter-Related Bloodstream Infections Long-Term Safety and Efficacy Data

BACKGROUND Catheter-related bloodstream infections (CRBSIs) are a serious complication in the provision of home parenteral nutrition (HPN). Antibiotic salvage of central venous catheters (CVCs) in CRBSI is recommended; however, this is based on limited reports. We assessed the efficacy of antibiotic salvage of CRBSIs in HPN patients. MATERIALS AND METHODS All confirmed CRBSIs occurring in patients receiving HPN in a national intestinal failure unit (IFU), between 1993 and 2011, were analyzed. A standardized protocol involving antibiotic and urokinase CVC locks and systemic antibiotics was used. RESULTS In total, 588 patients were identified with a total of 2134 HPN years, and 297 CRBSIs occurred in 137 patients (65 single and 72 multiple CRBSIs). The overall rate of CRBSI in all patients was 0.38 per 1000 catheter days. Most (87.9%) infections were attributable to a single microorganism. In total, 72.5% (180/248) of CRBSIs were salvaged when attempted (coagulase-negative staphylococcus, 79.8% [103/129], Staphylococcus aureus, 56.7% [17/30]; polymicrobial infections, 67.7% [21/30]; and miscellaneous, 66.1% [39/59]). CVC salvage was not attempted in 49 episodes because of life-threatening sepsis (n = 18), fungal infection (n = 7), catheter problems (n = 20), and CVC tunnel infection (n = 4). Overall, the CVC was removed in 33.7% (100/297) of cases. There were 5 deaths in patients admitted to the IFU for management of the CRBSI (2 severe sepsis at presentation, 3 metastatic infection). CONCLUSIONS This is the largest reported series of catheter salvage in CRBSIs and demonstrates successful catheter salvage in most cases when using a standardized protocol.

Enteroendocrine cells in gastrointestinal pathophysiology

Enteroendocrine cells in the gastrointestinal tract play an important role in the regulation of appetite and digestive responses through the secretion of peptides. Their involvement in gastrointestinal diseases has been acknowledged, but relatively few studies have sought to clearly define their role in the pathogenesis or as therapeutic targets. Recent, but still limited, work has identified new roles for EEC in GI diseases.

Replication and meta-analysis of 13,000 cases defines the risk for interleukin-23 receptor and autophagy-related 16-like 1 variants in Crohn's disease.

BACKGROUND/OBJECTIVE Variants in the interleukin-23 receptor (IL23R) and the autophagy-related 16-like 1 (ATG16L1) genes have been associated with an increased risk of Crohns disease (CD). Both genes were identified through genome-wide association scans and subsequent studies have validated these associations. To assess the effect size of these variants, an independent case-control association study and meta-analysis were performed. METHODS British Caucasian subjects with inflammatory bowel disease (n=500) and 877 ethnically matched controls were genotyped for the disease-associated variants in IL23R and ATG16L1. In addition, meta-analyses of 12,991 patients and 14,598 controls, and 11,909 patients and 15,798 controls, were conducted on independently published data for the associations between IL23R and ATG16L1 variants and CD, respectively. RESULTS In the present cohort, both susceptibility variants showed highly significant associations, including IL23R (rs11209026, P=0.0006; OR 0.37; 95% CI 0.21 to 0.67) and ATG16L1 (rs2241880, P=0.0017; OR 1.36; 95% CI 1.12 to 1.66). The meta-analysis based on the random effects model showed similar combined effects for rs11209026 (n=26, OR 0.41; 95% CI 0.37 to 0.46) and rs2241880 (n=25, OR 1.33; 95% CI 1.28 to 1.39). There was no statistically significant gene-gene interaction between caspase recruitment domain (CARD15) variants and the IL23R or ATG16L1 polymorphisms (P=0.44 and P=0.24, respectively). CONCLUSION The present cohort and meta-analysis provides strong evidence that, in addition to CARD15, polymorphisms in both IL23R and ATG16L1 alter susceptibility to CD and that these effects are consistent across all populations of European ancestry; however, only ATG16L1 is relevant to inflammatory bowel disease in the Asian population.

Antibiotic therapy for Crohn's disease: A review

Increasing evidence suggests that gut bacteria play a pathogenic role in Crohns disease (CD), providing a rationale for the use of antibiotics in the primary treatment of the disease. While there are data to suggest that antibiotics may be effective in treating active luminal, particularly colonic, and/or perianal CD, evidence for their use in these settings is hampered by the lack of well-designed, adequately powered, placebo-controlled trials. Furthermore, although nitroimidazole antibiotics have been shown to reduce postoperative recurrence following ileocolonic resection, their use is limited by side effects. There is a current need for rigorous multicentre studies looking into the role of antibiotics in treating perianal and luminal CD, as well as a need for the large-scale assessment of novel antibiotics, with low systemic absorption, which may improve patient tolerance.