BDNF and inflammatory bowel disease: The clinical relevance of BDNF has been demonstrated in several inflammatory pathologies of the gut; the neurotrophin is downregulated in the brain of a murine model of inflammatory bowel disease [17], whereas it appeared to be upregulated in the intestinal mucosa [18], as well as in the serum [19] of patients suffering from diarrhea-predominant irritable bowel syndrome.