Inhibiting connexin channels protects against cryopreservation-induced cell death in human blood vessels.
OBJECTIVE
Cryopreserved blood vessels are being increasingly employed in vascular reconstruction procedures but freezing/thawing is associated with significant cell death that may lead to graft failure. Vascular cells express connexin proteins that form gap junction channels and hemichannels. Gap junction channels directly connect the cytoplasm of adjacent cells and may facilitate the passage of cell death messengers leading to bystander cell death. Two hemichannels form a gap junction channel but these channels are also present as free non-connected hemichannels. Hemichannels are normally closed but may open under stressful conditions and thereby promote cell death. We here investigated whether blocking gap junctions and hemichannels could prevent cell death after cryopreservation.


METHODS
Inclusion of Gap27, a connexin channel inhibitory peptide, during cryopreservation and thawing of human saphenous veins and femoral arteries was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assays and histological examination.


RESULTS
We report that Gap27 significantly reduces cell death in human femoral arteries and saphenous veins when present during cryopreservation/thawing. In particular, smooth muscle cell death was reduced by 73% in arteries and 71% in veins, while endothelial cell death was reduced by 32% in arteries and 51% in veins.


CONCLUSIONS
We conclude that inhibiting connexin channels during cryopreservation strongly promotes vascular cell viability.
Department of Basic Medical Sciences - Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, Ghent 9000, Belgium.
M
M
Bol
C
C
Van Geyt
S
S
Baert
E
E
Decrock
N
N
Wang
M
M
De Bock
A K
AK
Gadicherla
C
C
Randon
W H
WH
Evans
H
H
Beele
R
R
Cornelissen
L
L
Leybaert
D000328:Adult; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D016009:Chi-Square Distribution; D018031:Connexin 43 / Q000037:antagonists & inhibitors / Q000378:metabolism; D017630:Connexins / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005263:Femoral Artery / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000637:transplantation; D006801:Humans; D020287:In Situ Nick-End Labeling; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009842:Oligopeptides; D012501:Saphenous Vein / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000637:transplantation; D000097003:Gap Junction alpha-5 Protein; D000097006:Gap Junction alpha-4 Protein
D018031:Connexin 43; D017630:Connexins; D003451:Cryoprotective Agents; D009842:Oligopeptides; D000097003:Gap Junction alpha-5 Protein; D000097006:Gap Junction alpha-4 Protein; C455880:gap 27 peptide