APOPTOSIS IN ISCHEMIA REPERFUSION INJURY OF HUMAN RENAL-ALLOGRAFTS/

Background. Ischemia/reperfusion injury of human renal allografts has a number of clinically significant consequences. A number of mechanism s of ischemia/ reperfusion injury have been elucidated, and there is e vidence that apoptosis may be a contributing factor. Methods. To exami ne immediate posttransplant events, fixed tissue sections from paraffi n-embedded wedge biopsy specimens taken before and after reperfusion o f human renal allografts were stained using terminal deoxytransferase- mediated dUTP nick-end labeling to detect the DNA fragmentation charac teristic of apoptosis. Thirty-six pairs of pre- and postreperfusion bi opsy specimens were examined, 11 from living-related donor renal trans plants and 25 from cadaveric donor transplants. Results. Quantitation of the terminal deoxytransferase-mediated dUTP nick-end labeling signa l showed that significantly more apoptosis occurred in postreperfusion compared with prereperfusion biopsy specimens from cadaveric donor tr ansplants, but a similar difference was not observed in living-related donor renal transplants. Furthermore, significantly more apoptosis wa s observed in postreperfusion biopsy specimens from cadaveric compared with living-related renal transplants. Postreperfusion biopsy specime ns from kidneys that were cold preserved longer than 30 hr had a highe r mean apoptosis score than those stored for less than 24 hr, but the result was not statistically significant. Conclusions. Thus, apoptosis occurs predominantly as a result of reperfusion after cold preservati on of cadaveric donor renal allografts and provides additional informa tion regarding the extent of ischemia/ reperfusion injury in an organ, The clinical value of this information remains to be determined.