Based on preclinical findings that sacral neuromodulation (SNM) reduces intestinal epithelial barrier (IEB) permeability, we conducted a clinical study in a cohort of patients with fecal incontinence to assess the impact of SNM upon ex vivo IEB permeability (rectal biopsies) and whether its variations could be predictive of therapeutic response.

In patients treated by SNM for fecal incontinence, rectal biopsies were harvested before, at the end of the test-period and after 6 months of stimulation for patients implanted. IEB permeability was assessed by measuring sulfonic acid flux across the rectal mucosa in ussing chambers (ex-vivo assessment).

Ten patients (median age 67 years) suffering from fecal incontinence underwent SNM test. Following the test-period of 3 weeks long, 6 (60 %) patients were considered responders and were implanted. We noticed an increase of paracellular permeability among non-responders between baseline and the end of the test-period. Paracellular permeability was also found to be higher in the group of responders as compared to non-responders at baseline but the difference did not reach statistical significance due to small sample size. There were no complications related to rectal biopsies.

These data that need to be confirmed in a larger set of patients suggest that functional study of the rectal mucosa in FI patients can putatively predict the therapeutic response to SNM and can be used as a biomarker of response.