Analogs of cyclic nucleotides in rat liver preservation.
BACKGROUND
Cyclic nucleotides mediate intracellular signal transduction of several vasodilators. In addition to its vascular relaxant effects, cAMP is known to protect endothelial cells and to suppress Kupffer cell activation. On the other hand, cGMP potently ameliorates adhesion of leukocytes and platelets. We tested the effects of two analogs of cyclic nucleotides (8bromo cyclic adenosine monophosphate [8br-cAMP] and 8bromo cyclic guanosine monophosphate [8br-cGMP]) in rat liver preservation.


METHODS
In experiment 1, either analog (0.1-1.0 mM) alone was added to University of Wisconsin (UW) solution in a survival study. In experiment 2, donors and recipients were also treated with 8br-cAMP or 8br-cGMP, with the following three groups tested: group 1=control; group 2=administration of 8br-cAMP to donors, UW solution, and recipients; group 3=administration of 8br-cGMP to donors, UW solution, and recipients. Experiment 3 tested combined treatments: group 4=administration of 8br-cGMP to donors and UW solution, and cAMP to recipients; group 5=administration of 8br-cAMP to donors and UW solution, and 8br-cGMP to recipients. To elucidate the roles of each nucleotide, two further groups were tested: group 6=administration of 8br-cAMP to donors and UW solution; group 7=administration of 8br-cGMP to recipients. In experiment 4, rats in groups 1, 5, 6, and 7 were killed at several time points after reperfusion, and percent graft blood flow (%BF), number of accumulated neutrophils, plasma levels of tumor necrosis factor-alpha and interleukin-1, and serum alanine aminotransferase levels were examined.


RESULTS
In experiments 1 and 2, no significant effect was observed on animal survival. In experiment 3, a significant increase in animal survival was observed only in group 5 (100%, 7/7, P=0.0004 vs. group 1: 16.7%, 2/12). In group 5, no improvement of %BF was observed during the early phase of reperfusion (15 and 30 min) compared with that in group 1. On the other hand, the %BF of group 5 was significantly higher in the later phase (6 hr), consistent with the decrease in accumulation of neutrophils observed then. Production of tumor necrosis factor-alpha and serum alanine aminotransferase levels were also reduced with this treatment. Histologically, the bleeding and segmental necrosis, observed in group 1, were completely prevented in group 5.


CONCLUSIONS
We conclude that restoration of grafts with cAMP and administration of cGMP to recipients led to successful transplantation, and that the two analogs acted synergistically in opposing preservation and reperfusion injury without improvement of graft blood flow during the early phase of reperfusion. The effect was due to their regulation of neutrophil activation and sequestration.
Maeda
T
T
Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pennsylvania 15213, USA.
Murase
N
N
Subbotin
V
V
Sakamoto
T
T
Yamada
T
T
Terakura
M
M
Todo
S
S
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000241:Adenosine / Q000494:pharmacology; D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D004338:Drug Combinations; D004357:Drug Synergism; D005978:Glutathione / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007375:Interleukin-1 / Q000097:blood; D008099:Liver / Q000187:drug effects* / Q000473:pathology; D008102:Liver Circulation / Q000187:drug effects; D008297:Male; D009926:Organ Preservation / Q000379:methods*; D019188:Organ Preservation Solutions / Q000494:pharmacology; D011184:Postoperative Period; D011887:Raffinose / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D015427:Reperfusion Injury / Q000517:prevention & control; D014019:Tissue Donors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D004338:Drug Combinations; D007328:Insulin; D007375:Interleukin-1; D019188:Organ Preservation Solutions; D014409:Tumor Necrosis Factor-alpha; C055206:University of Wisconsin-lactobionate solution; D015124:8-Bromo Cyclic Adenosine Monophosphate; C016276:8-bromocyclic GMP; D000493:Allopurinol; D005978:Glutathione; D006152:Cyclic GMP; D000241:Adenosine; D011887:Raffinose