Aims: The aim of this minireview is to describe the potential mechanisms of action of synbiotics in the treatment of ulcerative colitis by analyzing several in vitro, animal and human studies.
Background: Inflammatory bowel diseases, namely Crohn's disease and ulcerative colitis, are currently considered multifactorial pathologies in which various combined environmental factors act on a genetic background, giving rise to a chronic inflammation of the gastrointestinal tract. Ulcerative colitis is a chronic inflammation of the colon caused by a dysregulated immune response to host intestinal microbiota in genetically susceptible subjects. Ulcerative colitis has a strong impact on patients' quality of life, as well as high costs for the health-care system. A wide interest on the role in intestinal microbiota modulation in ulcerative colitis is emerging.
Objective: In this review, we discuss results from human and animal studies on the use of synbiotics for the treatment of UC, with particular attention to their ability to influence microbiota and the immune system.
Method: Analyzing of the most relevant in vitro, animal and human studies.
Result: Synbiotics are more effective than probiotics or prebiotics. Synbiotics are able to selectively stimulate bacteria already resident in the gut rather than probiotics alone, which should compete with the bacteria presents in host microbiota.
Conclusion: The mechanism of actions in synbiotics supplementation is still unclear and needs more investigation although there are a wide number of data indicating that the synergism between probiotics and prebiotics is able to modulate the inflammatory response through cytokine expression and immune cell modulation induced by probiotic bacteria, that are also able to favour the production of SCFA by prebiotics digestion. SCFA are involved in mucosal barrier stabilization, regulatory T cell induction, promotion of anti-inflammatory cytokines secretion and inhibition of inflammatory factors such as TNF-α.
Other: An urgent need is to create a panel of markers of inflammation, such as endoscopic or histologic scores and inflammatory markers that can give an accurate picture of UC progression/amelioration if used in a standard way in every study, as well as the use of an inflammatory bowel questionnaire to provide gastrointestinal symptom rating scale.