Effects of storage and reperfusion oxygen content on substrate metabolism in the isolated rat lung.
BACKGROUND
Lung transplantation requires a period of storage and ischemia; we examined the largely unknown effects of that period on intermediary metabolism.


METHODS
Two groups of isolated rat lung blocks (n = 16 each) were flushed with Euro-Collins solution and harvested. The lung blocks were immediately ventilated and either perfused for 30 minutes with an erythrocyte-based solution containing carbon 13 labeled substrates (group 1) or stored for 6 hours at 1 degree C and then reperfused (group 2). Half of each group was reperfused at a physiologic Po2 the other half at high Po2. Analysis of carbon 13 isotopomers was performed to determine substrate utilization through aerobic pathways in lung tissue.


RESULTS
Lungs from both groups oxidized all major substrates. The contribution of fatty acids to acetylcoenzyme acid oxidized in the citric acid cycle was significantly higher in group 2 than in group 1 (31.3% +/- 2.2% versus 22.0% +/- 2.1%, p < 0.05). Perfusate Po2 did not affect substrate preference. Gas exchange was worse in stored lungs.


CONCLUSIONS
After a period of hypothermic ischemia and storage, substrate preference in lung tissue exhibits a switch towards fatty acids. As fatty acid oxidation occurring after ischemia is deleterious in other organs, strategies to inhibit this process in stored lungs may warrant further investigation.
Meyer
P E
PE
Department of Surgery, University of Texas Southwestern Medical Center at Dallas, and the Dallas Veterans Affairs Medical Center, 75235, USA. dan.meyer@email.swmed.edu
Jessen
M E
ME
Patel
J B
JB
Chao
R Y
RY
Malloy
C R
CR
Meyer
D M
DM
D000818:Animals; D066298:In Vitro Techniques; D019194:Ischemic Preconditioning; D008168:Lung / Q000378:metabolism*; D016040:Lung Transplantation; D008297:Male; D009926:Organ Preservation; D010100:Oxygen / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion
D010100:Oxygen