Common biostructure of the colonic microbiota in neuroendocrine tumors and Crohn's disease and the effect of therapy.

BACKGROUND

The aims were to comparatively investigate the biostructure of colonic microbiota in patients with neuroendocrine tumors and Crohn's disease (CD) and to study the response of the microbiota to therapy.

METHODS

Sections of fecal cylinders from 66 patients with neuroendocrine tumors (NET; 25 foregut, 30 midgut, 11 hindgut), 50 patients with CD (Crohn's Disease Activity Index [CDAI] ≥150), and 30 patients with chronic idiopathic diarrhea seen at the Charité Hospital and 25 healthy controls were investigated using fluorescence in situ hybridization with probes specific for five bacterial groups: Faecalibacterium prausnitzii, Clostridium group XIVa / Roseburia group, Bacteroides, Enterobacteriaceae, and Bifidobacteriaceae.

RESULTS

We found a striking F. prausnitzii (Fprau) depletion in the stool of patients with NET of the midgut and patients with CD. The changes of the microbiota in the two other NET groups were uncharacteristic and similar to those observed in patients with chronic idiopathic diarrhea. Fprau depletion was reversible with chemotherapy and with interferon alpha-2b treatment in patients with midgut NET. Somatostatin analogs had no influence on Fprau concentrations.

CONCLUSIONS

Patients with NET and CD show similarities in their abnormalities of the fecal biostructure. Interferon alpha and systemic chemotherapy significantly improved the fecal biostructure in patients with midgut NET.