The immune-enhancing enteral agents arginine and glutamine differentially modulate gut barrier function following mesenteric ischemia/reperfusion.
BACKGROUND
Immune-enhancing enteral diets have been shown to improve patient outcome. One contributing mechanism may be via maintenance of gut barrier function. While recent data has shown that glutamine is beneficial, arginine may be harmful. We therefore hypothesized that the immune-enhancing agents, glutamine and arginine, differentially modulate gut barrier function.


METHODS
At laparotomy, rats had jejunal sacs filled with 10 mmol/L glutamine, arginine, fructose, or magnesium sulfate (osmotic control) followed by 60 minutes of superior mesenteric artery occlusion and 2 hours of reperfusion. Jejunum was harvested for histology, deconvolution microscopy, F:G actin, ATP, and permeability measurements.


RESULTS
Glutamine and fructose minimized mucosal injury compared with controls and arginine. Deconvolution microscopy confirmed that glutamine and fructose preserved the actin cytoskeleton but there was disruption by arginine which correlated with F:G actin ratios and tissue ATP levels. Permeability was enhanced by arginine compared with the other groups.


CONCLUSIONS
Arginine resulted in worsened mucosal injury, disruption of the actin cytoskeleton, decreased tissue ATP and enhanced permeability compared with glutamine which appeared protective. The immune-enhancing agent arginine results in breakdown of gut barrier function which may have important implications for critically injured patients.
Kozar
Rosemary A
RA
Departments of Surgery, University of Texas-Houston, Houston, Texas, USA. Rosemary.A.Kozar@uth.tmc.edu
Verner-Cole
Elizabeth
E
Schultz
Stanley G
SG
Sato
Nario
N
Bick
Roger J
RJ
Desoignie
Roland
R
Poindexter
Brian J
BJ
Moore
Frederick A
FA
D000199:Actins / Q000378:metabolism; D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000704:Analysis of Variance; D000818:Animals; D001120:Arginine / Q000627:therapeutic use*; D002463:Cell Membrane Permeability / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects; D004750:Enteral Nutrition / Q000379:methods*; D005973:Glutamine / Q000627:therapeutic use*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D008297:Male; D008641:Mesenteric Vascular Occlusion; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000276:immunology / Q000473:pathology / Q000628:therapy*
D000199:Actins; D000276:Adjuvants, Immunologic; D005973:Glutamine; D001120:Arginine