Effect of intravenous amino acids on interdigestive antroduodenal motility and small bowel transit time

Background—Patients on totalparenteral nutrition have an increased risk of developing gallstonesbecause of gall bladder hypomotility. High dose amino acids may preventbiliary stasis by stimulating gall bladder emptying.
Aims—To investigate whetherintravenous amino acids also influence antroduodenal motility.
Methods—Eight healthy volunteersreceived, on three separate occasions, intravenous saline (control),low dose amino acids (LDA), or high dose amino acids (HDA).Antroduodenal motility was recorded by perfusion manometry andduodenocaecal transit time (DCTT) using the lactulose breath hydrogen test.
Results—DCTT was significantlyprolonged during LDA and HDA treatment compared with control. Theinterdigestive motor pattern was maintained and migrating motor complex(MMC) cycle length was significantly reduced during HDA compared withcontrol and LDA due to a significant reduction in phase II duration.Significantly fewer phase IIIs originated in the gastric antrum duringLDA and HDA compared with control. Duodenal phase II motility index was significantly reduced during HDA, but not during LDA, compared with control.
Conclusions—Separate intravenousinfusion of high doses of amino acids in healthy volunteers: (1)modulates interdigestive antroduodenal motility; (2) shortens MMC cyclelength due to a reduced duration of phase II with a lower contractileincidence both in the antrum and duodenum (phase I remains unchangedwhereas the effect on phase III is diverse: in the antrum phase III is suppressed and in the duodenum the frequency is increased); and (3)prolongs interdigestive DCTT.

Keywords:amino acids; antroduodenal motility; small boweltransit time; total parenteral nutrition