An essential role of Ffar2 (Gpr43) in dietary fibre-mediated promotion of healthy composition of gut microbiota and suppression of intestinal carcinogenesis

Composition of the gut microbiota has profound effects on intestinal carcinogenesis. Diet and host genetics play critical roles in shaping the composition of gut microbiota. Whether diet and host genes interact with each other to bring specific changes in gut microbiota that affect intestinal carcinogenesis is unknown. Ability of dietary fibre to specifically increase beneficial gut microbiota at the expense of pathogenic bacteria in vivo via unknown mechanism is an important process that suppresses intestinal inflammation and carcinogenesis. Free fatty acid receptor 2 (FFAR2 or GPR43) is a receptor for short-chain fatty acids (acetate, propionate and butyrate), metabolites of dietary fibre fermentation by gut microbiota. Here, we show FFAR2 is down modulated in human colon cancers than matched adjacent healthy tissue. Consistent with this, Ffar2(-/-) mice are hypersusceptible to development of intestinal carcinogenesis. Dietary fibre suppressed colon carcinogenesis in an Ffar2-dependent manner. Ffar2 played an essential role in dietary fibre-mediated promotion of beneficial gut microbiota, Bifidobacterium species (spp) and suppression of Helicobacter hepaticus and Prevotellaceae. Moreover, numbers of Bifidobacterium is reduced, whereas those of Prevotellaceae are increased in human colon cancers than matched adjacent normal tissue. Administration of Bifidobacterium mitigated intestinal inflammation and carcinogenesis in Ffar2(-/-) mice. Taken together, these findings suggest that interplay between dietary fibre and Ffar2 play a key role in promoting healthy composition of gut microbiota that stimulates intestinal health.

Monitoring for Extra-Intestinal Cancers in IBD

Multiple studies have demonstrated an increased risk for extra-intestinal cancers in inflammatory bowel disease (IBD) patients, mainly from treatment modalities. Prominent cancers that are related to IBD treatment include the following: lymphoproliferative disorders associated with thiopurine use, hepatosplenic T cell lymphoma primarily in younger male patients on thiopurines and anti-tumor necrosis factor (TNF) agents, non-melanoma skin cancers in patients treated with thiopurines and anti-TNF agents, and melanomas in patients who are on monotherapy with anti-TNF agents. In addition, women with IBD may have higher rates of cervical dysplasia and cervical cancer. The focus of this review is to provide a comprehensive overview on extra-intestinal cancers in IBD patients and how to monitor for these malignancies.

Neurological events with tumour necrosis factor alpha inhibitors reported to the Food and Drug Administration Adverse Event Reporting System

BACKGROUND

The association between inhibition of tumour necrosis factor alpha (TNF-α) and new onset of neurological adverse events (AEs) is unclear.

AIMS

To evaluate neurological AEs with TNF-α inhibitors reported to the Food and Drug Administration Adverse Event Reporting System (FAERS) utilising a standardised scoring tool for drug-induced AEs.

METHODS

A search of FAERS for neurological AEs (January 1, 2000 to December 31, 2009) reported with infliximab, adalimumab, certolizumab and etanercept was performed. Full-text reports were accessed using the Freedom of Information Act and scored using Naranjo score, while accounting for temporal association, previous conclusive reports of the neurological AE with any TNF-α inhibitor, and alternate explanations including underlying disease, concomitant medications and comorbidities, such as diabetes mellitus.

RESULTS

There were 772 reports. Most were in patients who had rheumatoid arthritis (393, 50.9%) followed by inflammatory bowel disease (140, 18.1%). No significant differences in age or gender were seen between IBD patients compared with rheumatological diseases (P = 0.584 and P = 0.055 respectively). Etanercept was reported most (327, 42.4%) followed by infliximab (276, 35.8%) (P = 0.008). Peripheral neuropathy was the most common neurological AE (296 reports, 38.3%) followed by central nervous system and/or spinal cord demyelination (153 reports, 19.8%). Majority (551, 71.4%) of the reports were of 'possible' AE with the remaining 'probable' AE and none identified as 'definite' AE.

CONCLUSION

While several neurological AEs have been described, definite association between de novo development of these AEs and exposure to TNF-α inhibitors was not established using the Naranjo score.