n-butyrate rectal transport in cirrhotic patients

Data about colonic mucosa transport of short-chain fatty acids in cirrhotic patients are still lacking. The aim of the present study was to compare th e rectal mucosa transport of n-butyrate and its effect on transport of othe r electrolytes and endoluminal pH in normal subjects and in cirrhotic patie nts by using a rectal dialysis technique. Thirteen subjects with normal hep atic function tests and 17 cirrhotic patients were enrolled. Dialysis bags containing 80 mmol/liter of butyrate in a neutral pH (6.8) electrolyte solu tion were placed in the rectum of enrolled subjects for 60 min. Net transpo rt rate was calculated for butyrate, sodium, chloride., potassium, and bica rbonate. The differences in pH between initial and final dialysis solutions was also evaluated in the two groups in the study. Net butyrate absorption was significantly lower in cirrhotic patients than in controls (65.2 +/- 3 8.6 vs 101.2 +/- 45.3 nmol/min/cm(2), respectively; P = 0.02). Furthermore, cirrhotic patients showed a lower HCO3 secretion than controls (-26.9 +/- 19.9 vs -45.1 +/- 20.0, respectively; P = 0.01). No differences were found in transport of the other electrolytes. The pH in the final dialysis soluti on in cirrhotic patients was not significantly lower than in the controls ( 7.15 vs 7.35; P = 0.1). In conclusion, the impairment of butyrate absorptio n and the concurrent reduction of bicarbonate secretion observed in cirrhot ic patients may suggest a selective hypoactivity of apical HCO3-/SCFA(-) an tiport located at the colonocyte apical membrane.