Ileal resection: effect of cimetidine and taurine on intrajejunal bile acid precipitation and lipid solubilisation.

We have investigated whether pH-dependent bile acid precipitation limits lipid solubilisation after ileal resection, and whether treatment with cimetidine, or taurine improves solubilisation. Nine ileal resection patients were treated with placebo, cimetidine and taurine in random order for two weeks each. Upper jejunal content was aspirated and pooled according to pH for three hours after a standard Lundh test meal. On placebo, 50% of the bile acids were precipitated at pH less than 5, compared with only 26% at pH greater than 6, whilst aqueous-phase lipid concentration tended to be lower at pH less than 5 than at pH greater than 6 (5.1 vs 8.2 mmol/l). On cimetidine mean pH rose, particularly during the third hour (6.6 vs 5.8, p less than 0.05), associated with a reduction in bile acid precipitation (13.9 vs 33.1%, p less than 0.05), and an increase in aqueous-phase lipid concentration (10.4 vs 6.6 mmol/l, p less than 0.05). On taurine, the proportion of taurine conjugated bile acids increased (67 vs 22%, p less than 0.01), but there was no significant change in bile acid precipitation or lipid solubilisation. Lower jejunal samples were aspirated similarly from five of these patients on no treatment, and all were at pH greater than 6; apparent 'precipitation' was reduced (16.4 vs 28.1%), but lipid solubilisation did not improve. These findings suggest that pH dependent bile acid precipitation can limit lipid solubilisation within the jejunum after ileal resection, and that these effects can be reduced by cimetidine but not by taurine. Cimetidine may have a role in ileal resection patients with severe steatorrhoea unresponsive to dietary fat restriction.