Endothelial cell protection against ischemia/reperfusion injury by lecithinized superoxide dismutase.
BACKGROUND
Organs used for transplantation may experience long periods of cold ischemic preservation and consequently oxygen free radical-mediated damage following reperfusion. Lecithinized superoxide dismutase (lec-SOD) is a novel free radical scavenger that has been shown to bind with high affinity to cell membranes. The aim of this study was to determine whether lec-SOD bound to endothelial cells under organ preservation conditions to mediate direct antioxidant activity at the endothelial cell surface and thus offer protection against the harmful effects of ischemia/reperfusion injury.


METHODS
An in vitro study was performed on large vessel endothelial cells (HUVEC) and a human microvascular endothelial cell line HMEC-1, to investigate the potential therapeutic benefits of incorporating lec-SOD into organ preservation solution. A cold hypoxia/reoxygenation system was developed to examine lec-SOD binding affinity to endothelial cells, protection against hypoxia/reoxygenation-induced cell death, and neutrophil adhesion.


RESULTS
Lec-SOD bound to endothelial cells with higher affinity than unmodified recombinant human superoxide dismutase (rhSOD) and significantly protected both HUVEC and HMEC-1 from cell death following 27 hours of cold hypoxia (P < 0.01). Furthermore, neutrophil adhesion to the endothelium stimulated by hypoxia and reoxygenation was significantly inhibited by treatment with lec-SOD but not by lecithin or rhSOD (P < 0.01). Analysis by flow cytometry demonstrated that E-selectin and ICAM-1 were up-regulated by hypoxia/reoxygenation that was inhibited in part by lec-SOD.


CONCLUSIONS
The results from this study suggest that incorporation of lec-SOD into organ preservation solutions provides effective protection to endothelial cells against cold ischemia and reperfusion injury following transplantation.
Koo
D D
DD
Nuffield Department of Surgery, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Welsh
K I
KI
West
N E
NE
Channon
K M
KM
Penington
A J
AJ
Roake
J A
JA
Morris
P J
PJ
Fuggle
S V
SV
D000975:Antioxidants / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D015925:Cryopreservation; D019040:E-Selectin / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects*; D005434:Flow Cytometry; D005609:Free Radicals; D006801:Humans; D006982:Hypertonic Solutions / Q000737:chemistry / Q000494:pharmacology; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D016030:Kidney Transplantation; D009504:Neutrophils / Q000166:cytology; D019188:Organ Preservation Solutions / Q000737:chemistry / Q000494:pharmacology; D010713:Phosphatidylcholines / Q000494:pharmacology*; D015427:Reperfusion Injury / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology
D000975:Antioxidants; D019040:E-Selectin; D005609:Free Radicals; D006982:Hypertonic Solutions; C054581:Marshall's citrate solution; D019188:Organ Preservation Solutions; D010713:Phosphatidylcholines; D018799:Intercellular Adhesion Molecule-1; D013482:Superoxide Dismutase; C434045:lecithinized superoxide dismutase