Source: Gastroenterology  |  Posted 9 years ago

Inflammation and neuronal degeneration in the myenteric plexus are involved in the pathogenesis of irritable bowel syndrome (IBS), Swedish researchers suggest.

Investigators from the Karolinska Institute in Stockholm and the University of Lund at Malmo University Hospital in Malmo came to this conclusion after investigating full-thickness bowel biopsy specimens in 10 patients (two men, eight women) with severe IBS.

Few studies have looked for histopathological changes in the gut in IBS patients, the researchers note, and those that have only examined biopsy specimens from intestinal mucosa.

They used light microscopy to investigate tissue samples through routine stainings and immunohistochemical techniques. Horizontal sectioning provided visualisation of large areas of the myenteric plexus.

Autopsy specimens acted as controls for the myenteric plexus. Colorectal adenoma control came from terminal ileum biopsy and full-thickness jejunal biopsy specimens from patients with degenerative enteric neuropathy.

Results indicate low-grade infiltration of lymphocytes in the myenteric plexus in nine of the IBS patients. The lymphocytes had both peri- and intra-ganglionic locations. Mean number per ganglion ranged from 1.9 to 7.1 per patient, with an overall mean of 3.4.

No intra-ganglionic and only a few peri-ganglionic lymphocytes were found in controls, however.

There was neuron degeneration in six of the nine IBS patients with ganglionic lymphocyte infiltration and in the one patient without ganglionic lymphocyte infiltration, the investigators point out.