Effects of cardiopulmonary bypass on endothelin-1-induced contraction and signaling in human skeletal muscle microcirculation.
BACKGROUND
We investigated the effects of cardiopulmonary bypass (CPB) on the contractile response of human peripheral microvasculature to endothelin-1 (ET-1), examined the role of specific ET receptors and protein kinase C-alpha (PKC-α), and analyzed ET-1-related gene/protein expression in this response.


RESULTS
Human skeletal muscle arterioles (90 to 180 μm in diameter) were dissected from tissue harvested before and after CPB from 30 patients undergoing cardiac surgery. In vitro contractile response to ET-1 was assessed by videomicroscopy, with and without an endothelin-A (ET-A) receptor antagonist, an endothelin-B (ET-B) antagonist, or a PKC-α inhibitor. The post-CPB contractile response of peripheral arterioles to ET-1 was significantly decreased compared with pre-CPB response. The response to ET-1 was significantly inhibited in the presence of the ET-A antagonist BQ123 but unchanged in the presence of the ET-B receptor antagonist BQ788. Pretreatment with the PKC-α inhibitor safingol reversed ET-1-induced response from contraction to relaxation. The total protein levels of ET-A and ET-B receptors were not altered after CPB. Microarray analysis showed no significant changes in the gene expression of ET receptors, ET-1-related proteins, and protein kinases after CPB.


CONCLUSIONS
CPB decreases myogenic contractile function of human peripheral arterioles in response to ET-1. The contractile response to ET-1 is through activation of ET-A receptors and PKC-α. CPB has no effects on ET-1-related gene/protein expression. These results provide novel mechanisms of ET-1-induced contraction in the setting of vasomotor dysfunction after cardiac surgery.
Feng
Jun
J
Division of Cardiothoracic Surgery, Department of Surgery, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI 02903, USA.
Chu
Louis M
LM
Robich
Michael P
MP
Clements
Richard T
RT
Khabbaz
Kamal R
KR
Hagberg
Robert
R
Liu
Yuhong
Y
Osipov
Robert M
RM
Sellke
Frank W
FW
D000368:Aged; D000959:Antihypertensive Agents / Q000494:pharmacology; D002315:Cardiopulmonary Bypass; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism / Q000503:physiopathology; D020411:Oligonucleotide Array Sequence Analysis; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D051571:Protein Kinase C-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017466:Receptors, Endothelin / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology
D000959:Antihypertensive Agents; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D047428:Protein Kinase Inhibitors; D017466:Receptors, Endothelin; C086539:BQ 788; D051571:Protein Kinase C-alpha; D013110:Sphingosine; C005682:safingol; C072247:cyclo(Trp-Asp-Pro-Val-Leu)