Effect of temperature in long-term preservation of vascular endothelial and smooth muscle function

BACKGROUND. In clinical transplantation the donor organ is perfused with a cold preservation solution to obtain quick core cooling and a suitable environment for the tissue cells. Without good preservation of the vasculature, progressive deterioration of the blood flow during reperfusion may ultimately lead to the no-reflow phenomenon, even though the function of the other cells in the organ may be adequately preserved. The aim of this study was to find the optimal storage temperature for preservation of the vasculature. METHODS. The infrarenal aorta of 126 Sprague-Dawley rats were studied in organ baths: as fresh controls, after 36 hours of storage at 0.5 degrees C, 4 degrees C, 8.5 degrees C, and 22 degrees C in University of Wisconsin solution, and after 36-hour storage followed by transplantation and a lapse of 2 hours, 24 hours, and 7 days. The thromboxane analogue U-46619 was used to test contractility. Acetylcholine was used to elicit endothelium-dependent relaxation (EDR), and papaverine to elicit endothelium-independent relaxation. RESULTS. Storing the vessels at 0.5 degree C proved best regarding preservation of contractility, with a nonsignificant decrease, whereas storage at 4 degrees C and 8.5 degrees C resulted in a significant decrease after 36 hours. The contractility did not recover within 24 hours of in vivo reperfusion, but full recovery was seen after 7 days. Regardless of the preservation temperature used, a significant impairment in EDR was seen after 36 hours of storage. Two hours after transplantation, vessels stored at 4 degrees C and 8.5 degrees C showed no significant impairment in EDR, whereas those stored at 0.5 degrees C demonstrated a significant loss of EDR. After 24 hours and after 7 days, EDR was normal in all groups. CONCLUSIONS. Endothelium-dependent relaxing factor function is best preserved at 4 degrees C and 8.5 degrees C, whereas preservation of vascular smooth muscle function is best preserved at 0.5 degrees C.