Because older donor age is a major concern when considering kidneys for potential transplantation, we explored the actual impact of donor age on the features of kidneys that have been transplanted. We studied the correlations of donor age with molecular injury and rejection scores in 4502 kidney transplant biopsies assessed by microarrays, as well as function and postbiopsy survival. We used multivariable analyses to correct for the correlations of donor age with other predictive variables: recipient age, time of biopsy posttransplant, and deceased vs. living donors. Older donor age correlated with lower GFR and increased acute and chronic injury transcripts, but had no effect on rejection, which anti-correlated with recipient age. Acute injury transcripts peaked immediately posttransplant and regressed. Older donor age had little effect on acute molecular injury immediately posttransplant but strongly increased molecular injury scores at later times, peaking about 1-year posttransplant, indicating that older age does not increase molecular injury but increases failed repair post-injury. As expected, older donor age correlated with increased chronic injury and lower GFR, evident from the earliest time posttransplant, pre-transplant aging. However, despite significant age-related effects, the quantitative contribution of donor aging to molecular injury, function, and survival was very small.
Madill-Thomsen et al. (Thu,) studied this question.