Cold ischemia induces endothelin gene upregulation in the preserved kidney.
BACKGROUND
Prolonged cold ischemia time (CIT) can lead to posttransplant renal dysfunction; however, the pathophysiology remains unclear. Endothelin (ET), a potent vasoconstrictive peptide, may play a role in this injury. The purpose of this study was to determine if cold ischemia could induce renal ET-1 gene upregulation and to localize ET-1 peptide expression in the hypothermic kidney.


METHODS
Kidneys from Lewis rats were perfused with Viaspan, harvested, and stored at 4 degrees C for varying periods of CIT: 0, 6, 24, and 48 h. Preproendothelin-1 (ppET-1) gene upregulation was measured using a reverse-transcription polymerase-chain reaction. ET-1 peptide expression was localized using immunohistochemistry.


RESULTS
Control kidneys (0 h CIT) had 0. 56 +/- 0.22 DU of ppET-1 mRNA. After 6 h of CIT, a 2.3-fold increase in this level was noted. Following 24 h of CIT, ppET-1 mRNA was significantly upregulated to 1.96 +/- 0.38 DU (P < 0.05). Immunohistochemistry revealed typical vascular ET-1 staining in control kidneys. At 6 h of CIT, a significant increase in the expression of ET-1 was noted in the peritubular capillaries and vasa recta. After 24 h, intense staining for ET-1 was seen in the medullary collecting ducts. After 48 h of CIT, early cellular necrosis was present along with global decreases in ET-1 expression and ppET-1 mRNA levels.


CONCLUSIONS
This study demonstrates that 24 h of cold preservation can induce significant upregulation of the renal ET-1 gene and increase expression of the ET-1 peptide localized to both vascular endothelial and tubular epithelial surfaces of the kidney. Consequently, prolonged cold ischemia prior to transplantation may lead to delayed renal function following revascularization via endothelin-induced vasoconstriction and/or tubular impairment.
Wilhelm
S M
SM
Department of Surgery, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
Simonson
M S
MS
Robinson
A V
AV
Stowe
N T
NT
Schulak
J A
JA
D000818:Animals; D003080:Cold Temperature; D015925:Cryopreservation; D019332:Endothelin-1 / Q000378:metabolism; D016232:Endothelins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology*; D007150:Immunohistochemistry; D007511:Ischemia / Q000235:genetics*; D007668:Kidney / Q000502:physiology*; D008297:Male; D009926:Organ Preservation; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution / Q000502:physiology
D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D012333:RNA, Messenger