New insights in the etiology and pathophysiology of irritable bowel syndrome : Contribution of neonatal stress models

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, characterized by abdominal pain and disturbed defecation that cannot be explained by structural abnormalities. Although IBS symptoms (visceral pain, increased gut permeability, motility alterations) are clearly established, the etiology of this pathology is loosely understood. Nevertheless, clinical studies have reported that some early abuse (physical and psychological) is often associated with IBS development. Thus, loss and separation in the family during childhood may contribute to the IBS development. The recent development of animal models has pointed out the importance of early traumatic experiences in favoring the occurrence of IBS in adult life. Among these different models, neonatal maternal deprivation (NMD), neonatal colonic irritation (inflammatory stimuli), and neonatal colonic pain (rectal distension) have been described to mimic some cardinal features of IBS. The purpose of this review is 3-fold. First, to present the different neonatal stress models. Second, to review the literature on the influence of these early traumatic experiences on the gastrointestinal tract disturbances observed in adult life. Finally, we will also present the mediators and mechanisms involved in gut dysfunction triggered by NMD and probably in IBS.