Comparison of University of Wisconsin and St. Thomas' Hospital solutions on endothelium-derived hyperpolarizing factor-mediated function in coronary micro-arteries

Background. It is controversial whether coronary endothelial function is im paired after cold exposure to University of Wisconsin (UW) or St. Thomas' H ospital (ST) solution during heart transplantation, We therefore examined t he effects of cold storage of coronary micro-arteries with UW or ST solutio n on endothelium-derived hyperpolarizing factor (EDHF)-mediated function. Methods. Porcine and human coronary arteries were immersed in either UW or ST solution at 4 degrees C for 4 hr and then normalized in a wire myograph, Results. In the rings (normalized diameter: 200-500 mu M) precontracted by U-46619, EDHF-mediated relaxation and hyperpolarization were initiated by b radykinin (BK) or A(23187) in the presence of indomethacin and N-G-nitro-L- arginine. In the human coronary arteries, the EDHF-mediated relaxation to B K was reduced by UW solution from 53.2+/-5.6% to 24.0+/-2.7% (P=0.006), The reduced EDHF-mediated relaxation occurred concurrently with the decreased hyperpolarization to BK (17.0+/-1.5 vs. 10.5+/-1.1 mV, n=10, P=0.004) or A( 23187) in porcine coronary arteries. In the control arteries, K+ channel bl ockers, either glybenclamide or tetraethylammonium reduced the EDHF-mediate d relaxation, After exposure to UW solution, the EDHF-mediated relaxation w as further significantly inhibited. In contrast, ST solution did not affect , these responses. Conclusions. These results show that in coronary micro-arteries, UW, but no t ST, solution impairs the EDHF-mediated function and inhibits the Ca2+-act ivated and ATP-sensitive K+ channels. Our comparative study suggests that S T solution may be superior to Um solution in preserving the EDHF-related en dothelial function of coronary micro-arteries.