Potentiating the benefit of vascular-supplied glutamine during small bowel storage: importance of buffering agent.
BACKGROUND
Glutamine (gln)-supplemented University of Wisconsin (UW) solution improves overall small bowel (SB) preservation. Sustained gln metabolism in a system devoid of hepatic detoxification will necessarily result in the accumulation of pH active end products leading to nonphysiologic pH shifts. We hypothesized that simultaneous addition of N,N-bis[2-hydroxyethyl]-2-aminoethane sulfonic acid (BES), a known buffering agent, would potentiate the beneficial effect of gln supplementation by addressing the fundamental metabolic principle of pH homeostasis.


METHODS
Sprague-Dawley SB rats were administered a vascular flush with one of four solutions: UW; UW+90 mM BES (UWB); UW+2% gln (UWG); or UW+2% gln+90 mM BES (UWBG). Indices of energetics, barrier function, gln catabolism, and histology (light and electron microscopy) were assessed over a 10-hr cold storage time course.


RESULTS
Superior gln utilization in the UWBG group was indicated by elevated levels of key catabolites (glutamate, aspartate, glycine, ammonia). The addition of BES and gln resulted in significantly higher levels of all energetic parameters (ATP, total adenylates) at 10 hr compared with UW, UWB, and/or UWG. Barrier function was markedly improved after 10 hr storage in the UWBG group; mannitol permeability was 169 nmol/cm2/hr versus 572 and 445 nmol/cm(2)/hr (for UW and UWG, respectively). Histologic injury at 10 hr was 5.5, 7.5, and 8 (Park's grade) for UWBG, UWG, and UW. Ultrastructural damage was markedly reduced with UWBG, as assessed by grade of mitochondria damage.


CONCLUSIONS
This study strongly supports that the beneficial effects of gln-enriched UW solution can be amplified when combined with an effective buffering agent such as BES.
Olson
David W
DW
Surgical-Medical Research Institute, University of Alberta, Edmonton, Alberta, Canada T6G 2N8.
Fujimoto
Yasuhiro
Y
Madsen
Karen L
KL
Stewart
Brian G
BG
Carle
Michelle
M
Zeng
Janice
J
Jewell
Laurence
L
Sheasgreen
Jennifer L
JL
Chong
Feng T
FT
Kneteman
Norman M
NM
Bigam
David L
DL
Churchill
Thomas A
TA
D000241:Adenosine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000032:analysis; D000493:Allopurinol / Q000494:pharmacology*; D000818:Animals; D002952:Citric Acid Cycle; D005973:Glutamine / Q000378:metabolism / Q000494:pharmacology*; D005978:Glutathione / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000494:pharmacology*; D007421:Intestine, Small / Q000473:pathology / Q000637:transplantation* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D009926:Organ Preservation; D019188:Organ Preservation Solutions; D010539:Permeability; D011887:Raffinose / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D007328:Insulin; D019188:Organ Preservation Solutions; C055206:University of Wisconsin-lactobionate solution; D005973:Glutamine; D000493:Allopurinol; D000255:Adenosine Triphosphate; D005978:Glutathione; D000241:Adenosine; D011887:Raffinose