Role of functional brain imaging in gastroenterology in health and disease

The efficacy of probiotics in IBS

The clear delineation of a postinfective variety of irritable bowel syndrome (IBS), and the description, in a number of studies, of evidence of low-grade inflammation and immune activation in IBS, suggest a role for a dysfunctional relationship between the indigenous flora and the host in IBS and, accordingly, provide a clear rationale for the use of probiotics in this disorder. Other modes of action, including bacterial displacement and alterations in luminal contents, are also plausible. Although clinical evidence of efficacy is now beginning to emerge, a review of available trials emphasizes the importance of clear definition of strain selection, dose, and viability. The possible roles of cotherapy or sequential therapy with antibiotics, probiotics, prokinetics, or other agents, also deserve further study. The role of the enteric flora is evidently an area of great potential in IBS; we are on the threshold of a new era of research and therapy for this common disorder.

Probiotics in irritable bowel syndrome: an immunomodulatory strategy?

The clear delineation of a post-infective variety of IBS, as well as the description, in a number of studies, of evidence of low-grade inflammation and immune activation in IBS, suggest a role for a dysfunctional relationship between the indigenous flora and the host in IBS and, accordingly, provide a clear rationale for the use of probiotics in this disorder. Other modes of action, including bacterial displacement and alterations in luminal contents, are also plausible. While clinical evidence of efficacy is now beginning to emerge, a review of available trials emphasizes the importance of a clear definition of strain selection, dose and viability. The possible roles of co-therapy or sequential therapy with antibiotics, probiotics, prokinetics, or other agents also deserves further study. The role of the enteric flora is evidently an area of great potential in IBS; we are on the threshold of a new era of research and therapy for this common disorder.

Functional dyspepsia: The role of visceral hypersensitivity in its pathogenesis

Functional, or non-ulcer, dyspepsia (FD) is one of the most common reasons for referral to gastroenterologists. It is associated with significant morbidity and impaired quality of life. Many authorities believe that functional dyspepsia and irritable bowel syndrome represent part of the spectrum of the same disease process. The pathophysiology of FD remains unclear but several theories have been proposed including visceral hypersensitivity, gastric motor dysfunction, Helicobacter pylori infection and psychosocial factors. In this review, we look at the evidence, to date, for the role of visceral hypersensitivity in the aetiology of FD.

Disturbances of motility and visceral hypersensitivity in irritable bowel syndrome: biological markers or epiphenomenon

Motility and visceral hypersentitivity are regarded as the primary mechanisms of symptom development in irritable bowel syndrome(IBS). While a variety of motor abnormalities have been described throughout the gastrointestinal tract in IBS, their specificity and relationship to symptoms remain unclear. Visceral hypersensitivity is ubiquitous in functional gastrointestinal disease and is especially common in IBS. Again, however, its specificity for IBS has been questioned. Many factors, including stress and psychopathology,complicate the interpretation of these phenomena and new re-search suggests that mucosal inflammation and luminal factors may be more fundamental to the etiology of this common disorder.

Current concepts of the irritable bowel syndrome

The irritable bowel syndrome is one of the most common clinical problems encountered by the generalist and gastroenterologist. The goal of this review is to critically evaluate, based on available peer-reviewed literature, the current status of our understanding of the pathophysiology of the irritable bowel syndrome. The epidemiology of this disorder, including the characteristics of its presentation, natural history and associated phenomena, have been clarified. Differences between those who seek specialist care ('the consulters') and those in the community are now recognized. While, in both, symptoms may be similar in nature and severity; 'the consulters' are differentiated by how they react to their complaints. In terms of pathophysiology, the focus has moved to visceral sensation and central perception and has led to the identification of visceral hypersensitivity, visceral hyperalgesia and abnormal central perception of visceral events. This is not to dismiss dysmotility; subtle abnormalities in gas transit may be closely associated with the induction of certain symptoms. On the psychological front, attention now focuses on such complex issues as somatosization, abuse and response to major life events. Interactions between enteric flora, mucosal inflammation, immune phenomena and the enteric neuro-muscular apparatus also attract interest; the entity of post-infectious irritable bowel is now clearly recognized and there is experimental evidence to suggest a role for inflammation. While the precise aetiology of irritable bowel syndrome remains uncertain, considerable progress has been made, with recent advances in pathophysiology offering hope for the development of new therapeutic approaches.