Glutamine and Intestinal Immune Cells in Humans

Abstract

Background: Total parenteral nutrition (TPN) is associated with depletion of intestinal immune cells and increased gut permeability (GP). Adding glutamine (GLN) to TPN preserves GP by an unknown mechanism. Intestinal immune cells situated between the enterocytes (intraepithelial lymphocytes, [IEL]) influence GP in vitro. To obtain insight into the underlying mechanism of GLN on GP, we investigated the effects of GLN-supplemented TPN on IEL, immunoglobulin A (IgA) plasma cells and goblet cells, and enterocyte proliferation in intestinal biopsies. Methods: Twenty patients randomly received GLN-enriched TPN (GT) or isonitrogenous standard TPN (ST). Proliferation and number of immune cells were measured in intestinal biopsies obtained before and after 10 days of TPN. Results: No change in proliferative activity or in number of IgA plasma cells was observed. Goblet cells increased in the ST group, whereas the change seen in the GT group did not reach significance. In the GT group, IEL decreased, whereas in the ST group, no change in the number of IEL was observed. Conclusions: TPN was not associated with changes in proliferative activity or with depletion of gut immune cells. The data indicate that GLN-supplemented TPN has a different effect on intestinal immune cells compared with standard TPN. (Journal of Parenteral and Enteral Nutrition 21:310-315, 1997)