Methylprednisolone and tacrolimus prevent hypothermia-induced endothelial dysfunction.
BACKGROUND
Hypothermia is used to preserve organs for transplantation and is the oldest method to protect organs during complex pediatric cardiac surgery. Loss of tissue function and tissue edema are common complications in children undergoing corrective cardiac surgery and heart transplantation. The present study was designed to examine the effects of methylprednisolone and tacrolimus on endothelial cell function and morphology after deep hypothermia and rewarming.


METHODS
Human umbilical vein endothelial cells were pre-treated with methylprednisolone or tacrolimus, or both, incubated within a specially designed bioreactor or in monolayers, and then exposed to a dynamic cooling and rewarming protocol. Immunocytochemistry, time-lapse video microscopy, cell permeability and adherence assays, and Western blot analysis were performed.


RESULTS
Confluent endothelial cells exposed to hypothermia displayed elongated cell shapes with intercellular gap formation, increased endothelial cell-layer permeability, and loss in adherence. Upon rewarming, however, endothelial cell integrity was restored. Opening and closing of intercellular gaps was dependent on extracellular signal-regulated kinase 1 and 2 (ERK 1/2) activation and connexin 43 expression. The combined treatment with methylprednisolone and tacrolimus inhibited these hypothermia-induced changes.


CONCLUSIONS
These results suggest that methylprednisolone and tacrolimus inhibit hypothermia-induced endothelial gap formation by phosphorylated ERK 1/2 inhibition and connexin 43 stabilization. Application of combined drugs that affect multiple targets may therefore be considered as a possible new therapeutic strategy to prevent endothelial dysfunction after hypothermia and rewarming.
Diestel
Antje
A
Department of Pediatric Cardiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Billecke
Nils
N
Roessler
Joerg
J
Schmitt
Boris
B
Troeller
Silke
S
Schwartlander
Ruth
R
Berger
Felix
F
Sauer
Igor Maximilian
IM
Schmitt
Katharina Rose Luise
KR
D002448:Cell Adhesion / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000503:physiopathology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D007035:Hypothermia / Q000150:complications*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007365:Intercellular Junctions / Q000187:drug effects; D008775:Methylprednisolone / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016559:Tacrolimus / Q000494:pharmacology*
D018031:Connexin 43; D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D016559:Tacrolimus; D008775:Methylprednisolone