Background: Pre-transplant prediction of post-transplant renal function and outcome is
extremely challenging, particularly when applied to older and marginal donor organs. We
and others have demonstrated previously that allograft bio-age, as determined by CDKN2A
expression level, is a superior prognostic and predictive marker for post transplant
function. The CDKN2 locus is complex, comprising a series of developmentally and
epigenetically regulated transcript isoforms. Transcriptional regulation of these isoforms
incorporates a broad range of MicroRNAs (miRNA), non-coding, single-stranded RNA
molecules that are involved in the regulation of a variety of biological processes, including
embryogenesis, differentiation, and senescence. We have sought to investigate whether
CDKN2 associated miRNAs expression profile in „zero hour‟ pre-transplant renal allograft
biopsies are linked to clinico-pathological and functional characteristics post-transplant.
Methods: MicroRNA profiles were determined in „zero hour‟ allograft biopsies using microfluidic
TaqMan® MicroRNA arrays (Applied Biosystem) and were analysed in relation to
clinical data including serum creatinine (SC), cold ischaemia time (CIT), donor age and
acute rejection. Data were analysed using StatMiner® (Integromics). Furthermore,
MicroRNA data were validated using individual assays.
Results: 19miRNAs showed pre transplant expression levels that correlated with levels of
SC at 6 months post-transplantation and CIT. Significantly, linear regression analyses in
the cohort (n=43) revealed that pre-transplant expression of five miRNAs (hsa-miR-125b,
hsa-miR-505, hsa-miR-125a-5p, hsa-miR-96 and hsa-miR-1275) were associated with
acute rejection episodes (p<0.01).With the exception of hsa-miR-505, these miRNAs also
demonstrated an association with CIT.
Conclusions: This data indicates that miRNA profiling has clear potential to be used for
pre transplant assessment of post transplant allograft function. It offers the potential for
prediction of rejection episodes or other complications. Furthermore, there are also clear
links with donor bio-age, which may further enhance the diagnostic possibilities