Significance of Serum Bile Acids in Small Bowel Allograft Rejection in Pigs

Abstract

To examine changes in individual bile acids in serum in a pig model of allogenic small bowel transplantation. Seventeen pigs were divided into two groups: group 1 (n=10), controls; group 2 (n=7), allotransplantation, nonimmunosuppressed recipients. Both groups received a segmental intestine. Intestinal specimens for histologic studies were obtained at the end of cold flushing (T0) and on postoperative day 8 (T1). Total and individual bile acid concentrations were measured in serum samples taken at T0 and T1. All animals survived until the end of the study. In group 1, intestinal histology revealed no significant changes between T0 and T1 specimens. In contrast, in group 2, graft histology revealed moderate to severe rejection at T1 in all specimens. In contrast to group 1, serum levels of total bile acids increased significantly in group 2 at T1 compared with baseline (P=0.001). The increase was due to secondary bile acids which were significantly higher at T1 compared with baseline (P=0.0003). In contrast, secondary bile acids increased but not significantly at T1 in group 1 compared with baseline (P=0.056). Our study suggests that total and secondary serum bile acids may be a useful diagnostic tool for the diagnosis of acute intestinal rejection.