Changes in intragraft gene expression secondary to ischemia reperfusion after cardiac transplantation.
BACKGROUND
Ischemia-reperfusion (I/R) injury in transplanted tissue is associated with changes in intragraft cytokines, chemokines, and adhesion molecules. The aim of this study was to perform a comprehensive analysis of gene expression in cardiac grafts secondary to I/R using microarray technology.


METHODS
Heterotopic brown Norway rat cardiac isografts were removed on postoperative day (POD) 3, 5, and 7. RNA was extracted, hybridized on U34A-Affymetrix high-density gene expression arrays, and compared with nontransplanted hearts using the log-average ration (LAR) and Student test.


RESULTS
Of the approximately 8,799 transcripts tested on each chip, 557 were significantly increased by POD5, with fewer induced transcripts observed on POD3 (46) and POD7 (32). The most significantly induced transcripts included MHC class II molecules, interferon-gamma inducing factor, apolipoprotein E, and cathepsin S. In contrast, the highest number of down-regulated transcripts was seen on POD3 (746) with fewer transcripts down-regulated by POD5 (162) and POD7 (298). Down-regulated transcripts included those involved in cellular metabolism: monoamine oxidase-A, mitochondrial-A synthase complex, and cytochrome oxidase subunit. By POD7, oxidative stress inducible protein tyrosine phosphatase and vascular endothelial cell growth factor were significantly decreased in transplanted isografts. Reverse-transcriptase polymerase chain reaction (RT-PCR) data on 10 transcripts agreed with the microarray results.


CONCLUSIONS
Microarrays using LAR analyses generally agree with previous data regarding intragraft changes during I/R injury but provide a larger number of molecules for future study. Although the largest number of down-regulated genes was seen early, the I/R effect may be continuing in that many transcripts remain down-regulated 7 days after transplantation.
Stegall
Mark D
MD
Department of Surgery, Division of Transplantation, Mayo Foundation and Clinic, Rochester, MN 55905, USA. stegall.mark@mayo.edu
Park
Walter D
WD
Kim
Dean Y
DY
Covarrubias
Marco
M
Khair
Anis
A
Kremers
Walter K
WK
D000818:Animals; D015870:Gene Expression; D016027:Heart Transplantation / Q000502:physiology*; D008297:Male; D017202:Myocardial Ischemia / Q000235:genetics*; D015428:Myocardial Reperfusion Injury / Q000235:genetics*; D009206:Myocardium / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D011184:Postoperative Period; D051381:Rats; D011914:Rats, Inbred BN; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors