Ischemia- reperfusion injury and its influence on the epigenetic modification of the donor kidney genome.
BACKGROUND
In clinical transplantation, ischemia-reperfusion injury (I/RI) causes damage to DNA. We hypothesize that one form of damage is the demethylation of methylated cytosines in the donor genome caused by the oxidative environment created first by ischemia, and subsequently by reperfusion on transplantation. This study contributes to the understanding of how the short-lived and transient ischemic insult may influence chronic pathological changes that occur in clinical transplantation in the long term.


METHODS
A model of I/RI and chronic rejection; Fisher to Fisher kidney transplant rendered cold-ischemic for 4 hr before transplantation, to induce antigen-independent chronic nephropathy over a 6-month period, was used. Tissue was assessed by histopathology and methylation by pyrosequencing analysis.


RESULTS
An epigenetic map of the rat renal C3 promoter was produced, which identified methylated Cytosine phospho Guanine (CpG) sites coincident to cytokine response elements and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) binding sites. Pyrosequencing analysis showed that the tissue that had undergone 4 hr ischemia and reperfusion developed aberrant demethylation of cytosines in putative regulatory sites within the C3 promoter.


CONCLUSIONS
These findings may describe a newly recognized phenomena in the field of transplantation. Aberrant demethylation has long been linked to the development of tumors, and our data suggest a similar mechanism of gene dysregulation that may be initiated by I/RI with acute and chronic effects. These data may contribute to a further understanding of how the short lived and transient ischemic insult influences chronic pathological changes that occur even in the absence of major histocompatibility complex disparity in transplantation.
Parker
Marie D
MD
Leeds Institute of Molecular Medicine, St James's University Hospital, Leeds University, Leeds, United Kingdom.
Chambers
Philip A
PA
Lodge
J Peter A
JP
Pratt
Julian R
JR
D000818:Animals; D001483:Base Sequence; D003176:Complement C3 / Q000235:genetics; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005786:Gene Expression Regulation; D016678:Genome / Q000502:physiology*; D007668:Kidney / Q000502:physiology; D016030:Kidney Transplantation / Q000276:immunology / Q000502:physiology*; D008285:Major Histocompatibility Complex / Q000235:genetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D051381:Rats; D011916:Rats, Inbred F344 / Q000235:genetics*; D015427:Reperfusion Injury / Q000503:physiopathology*; D014185:Transplantation, Isogeneic / Q000502:physiology*
D003176:Complement C3; D004247:DNA