Butyrate absorption and lactate secretion in ulcerative colitis

Area of Science:

• Gastroenterology and Colorectal Research
• Molecular and Cellular Biology of the Gut
• Inflammatory Bowel Disease Pathophysiology

Background:

• Ulcerative colitis (UC) is associated with altered fecal electrolyte and organic anion concentrations, indicating changes in colon epithelial transport.
• Limited information exists regarding mucosal butyrate absorption in active ulcerative proctosigmoiditis.

Purpose of the Study:

• To investigate and quantify the net absorption rates of butyrate and L-lactate in the rectum of patients with active and quiescent ulcerative colitis.
• To compare rectal butyrate and electrolyte absorption in UC patients with healthy controls.

Main Methods:

• Rectal dialysis bags containing butyrate solution were used to measure net absorption/secretion rates.
• Measurements included butyrate, L-lactate, and electrolytes in 12 active UC patients, 10 quiescent UC patients, and 10 healthy controls.

Main Results:

• Butyrate absorption rates were comparable across active UC (7.5 ± 0.4 µmol/cm²/h), quiescent UC (6.6 ± 0.4 µmol/cm²/h), and healthy controls (6.3 ± 0.5 µmol/cm²/h).
• Sodium absorption was significantly reduced in active UC (11.5 ± 1.4 µmol/cm²/h) compared to quiescent UC (15.4 ± 1.0 µmol/cm²/h) and controls (18.7 ± 0.8 µmol/cm²/h).
• Significant L-lactate secretion was observed in active UC patients (0.9 ± 0.2 µmol/cm²/h) compared to quiescent UC and controls (both ≈0.2 µmol/cm²/h).

Conclusions:

• Rectal butyrate absorption is preserved in ulcerative colitis, supporting the potential efficacy of butyrate enema therapies.
• The inflamed colonic mucosa in UC actively secretes L-lactate, explaining elevated fecal lactate levels.
• Compromised sodium absorption in active UC highlights epithelial transport dysfunction beyond butyrate handling.