Rectal potential differences in irritable bowel syndrome and in inflammatory bowel diseases in man

Abstract

We have studied rectal potential difference (pd) in 200 subjects: 30 healthy volunteers or control patients, 46 patients with irritable bowel syndrome (IBS) and painless diarrhoea (group I), 60 IBS patients without diarrhoea (group II) and 64 patients with inflammatory bowel disease (IBD) with (group III, n = 41) or without (group IV, n = 23) rectal involvement. Pd measurement used a rectal perfused probe and a subcutaneous needle both connected, via agar-KCl bridges, to calomel electrodes and a millivoltmeter. Statistical analysis used Student's t-test for paired and unpaired data and Mann-Whitney U-test as appropriate. Mean rectal pd values were, respectively -43.5 +/- 8.7 mV in control group, -32.9 +/- 10.2 mV in IBS-group I patients (P less than 0.001), -41.3 +/- 12 mV in IBS-group II patients (NS), -21.4 +/- 14.1 mV in IBD patients with rectal involvement (P less than 0.001), and -45.1 +/- 14.3 mV in IBD-group IV patients (NS). A histological examination was performed in 36 IBS patients; mean rectal pd was significantly decreased in patients showing abnormal patterns (n = 27, pd = -31.8 +/- 9 mV) compared to patients with normal mucosa (n = 9, pd = -41.1 +/- 6.5 mV; P less than 0.01). These results show that: (1) potential difference is significantly decreased in patients with ulcerative and rectal involvement; (2) in patients with Crohn's disease, normal rectal pd values do not assess the appearance of colonic mucosa above; (3) patients with IBS and diarrhoea also present a significant diminution in mean rectal pd. Although the mechanisms involved remain unclear, rectal pd measurement appears to be an objective test for intestinal mucosae weakness in functional or inflammatory diseases of the large intestine and rectum.

Persistent epithelial barrier alterations in a rat model of postinfectious gut dysfunction

“…Interestingly, IgE‐induced responses in Isc were attenuated in previously infected animals. This, together with the increased tonic activity of MMCs, might suggest the presence of desensitization mechanisms to MMC mediators, as previously described in patients of gastrointestinal disorders associated with mastocitosis 21 . Alternatively, reduced secretory responses to MMC mediators, together with the alterations in epithelial and neural responses discussed previously, might represent the interplay of feedback regulatory mechanisms aiming to minimize a state of continuous epithelial overstimulation.…”

“…In addition, Ussing chamber studies performed to evaluate this postinfectious phase demonstrated EBF disruptions which resemble to a certain extent findings in patients with functional gastrointestinal disorders 20–23 . In particular, alterations in electrical conductance and passage of fluorescent tracers revealed a significant jejunal permeability defect during the postinfectious phase in the rat.…”

Protease‐activated receptor 2 and gut permeability: a review

“…Even though until now, no correlation has been established between fecal level of serine‐protease activity and the intensity/frequency of symptoms, it is tempting to speculate, based on animal data, that such activity contributes to the genesis of symptoms and particularly abdominal pain in these patients. Interestingly, a decreased colonic potential difference, corresponding to an increase in permeability, has been found in IBS‐D 49 and UC 50 patients compared with healthy subjects. We can speculate that this decreased potential difference is linked to the elevated protease activity found in these patients through an activation of PAR‐2.…”

Elevated motility‐related transmucosal potential difference in the upper small intestine in the irritable bowel syndrome

“…The importance of the colon in relation to bowel habits is illustrated by the fact that constipation occasionally occurs also in patients with celiac disease. 24 A concomitant disturbance in colonic mucosal function may indeed occur in d-IBS, as Pienkowski et al 33 have shown that a group of d-IBS patients had a decreased colonic PD compared with controls, a pattern similar to that in ulcerative colitis, 34,35 although of lower magnitude. When interpreting the current data, one should regard the motility-related PD signal as a marker for submucous plexus activity at the measuring site only.…”