Function and clinical implications of short-chain fatty acids in patients with mixed refractory constipation

The present study was designed to investigate the function and clinical implications of stool short-chain fatty acids (SCFAs) in patients with mixed refractory constipation.

Ascending colon specimens obtained from 30 patients with ascending colon cancer were regarded as the control group. Ascending colon specimens obtained from patients with mixed refractory constipation were regarded as the experimental group and were divided into three subgroups, according to Wexner scores [A constipation scoring system to simplify evaluation and management of constipated patients. Dis Colon Rectum 1996; 39: 681-5] of 16-20, 21-25 and 26-30, with 30 patients in each group. The stool SCFAs were extracted and quantitatively analysed using gas chromatography-mass spectrometry (GC-MS). The expression of G protein-coupled receptor 43 (GPR43) and of choline acetyltransferase (ChAT) were detected by immunofluorescence, reverse transcription-polymerase chain reaction (RT-PCR) and western blotting of colon samples.

The levels of acetate, propionate and butyrate were significantly lower in the experimental group than in the control group (P < 0.05). Compared with the control group, the densitometric quantification and mean density of GPR43 and ChAT proteins, and expression of GPR43 and CHAT genes, were significantly decreased in the patients with mixed refractory constipation (P < 0.05).

In the patients with mixed refractory constipation, the levels of stool SCFAs, including acetate, propionate and butyrate, as well as the levels of GPR43 and ChAT expressed in the colon, which were all negatively correlated with the Wexner score, were decreased and may be associated with the pathogenesis of mixed refractory constipation.