New insights into the pathophysiology of irritable bowel syndrome: implications for future treatments.

Irritable bowel syndrome (IBS) is a multifactorial disorder characterized by abdominal pain and altered bowel habits. Chronic symptoms may occur due to changes in gastrointestinal motor function, enhanced perception of gut stimuli, and psychosocial factors. Recent data suggest that abnormal processing of afferent signals occurs in IBS patients. A newly recognized causative factor in a subset of IBS patients is post-infectious IBS. Altered transport of intestinal gas and bowel distention may contribute to abdominal discomfort, pain, and bloating. Changes in gut microflora have also been reported, but data remain scant. Advances have been made in our understanding of serotonin signaling and metabolism in IBS patients, in part due to the introduction of specific receptor agonists and antagonists. Finally, exciting data are emerging on genetic alterations that may contribute to the pathophysiology and treatment of IBS. Increasingly novel mechanisms are being identified that should aid in better understanding of the complex pathophysiology of IBS and developing new therapies.