Active site inhibited factor VIIa attenuates myocardial ischemia/reperfusion injury in mice.
BACKGROUND
Inhibition of specific coagulation pathways such as the factor VIIa-tissue factor complex has been shown to attenuate ischemia/reperfusion (I/R) injury, but the cellular mechanisms have not been explored.


OBJECTIVE
To determine the cellular mechanisms involved in the working mechanism of active site inhibited factor VIIa (ASIS) in the protection against myocardial I/R injury.


METHODS
We investigated the effects of a specific mouse recombinant in a mouse model of myocardial I/R injury. One hour of ischemia was followed by 2, 6 or 24 h of reperfusion. Mouse ASIS or placebo was administered before and after induction of reperfusion.


RESULTS
ASIS administration reduced myocardial I/R injury by more than 40% at three reperfusion times. Multiplex ligation dependent probe amplification (MLPA) analysis showed reduced mRNA expression in the ischemic myocardium of CD14, TLR-4, interleukin-1 (IL-1) receptor-associated kinase (IRAK) and IkappaBalpha upon ASIS administration, indicative of inhibition of toll-like receptor-4 (TLR-4) and subsequent nuclear factor-kappaB (NF-kappaB) mediated cell signaling. Levels of nuclear activated NF-kappaB and proteins influenced by the NF-kappaB pathway including tissue factor (TF) and IL-6 that were increased after I/R, were attenuated upon ASIS administration. After 6 and 24 h of reperfusion, neutrophil infiltration into the area of infarction was decreased upon ASIS administration. There was, however, no evidence of an effect of ASIS on apoptosis (Tunel staining and MLPA analysis).


CONCLUSIONS
We conclude that the diminished amount of myocardial I/R injury after ASIS administration is primarily due to attenuated inflammation-related lethal I/R injury, probably mediated through the NF-kappaB mechanism.
Loubele
S T B G
ST
Department of Internal Medicine, Laboratory for Clinical Thrombosis and Haemostasis, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands. sarah.loubele@bioch.unimaas.nl
Spek
C A
CA
Leenders
P
P
van Oerle
R
R
Aberson
H L
HL
van der Voort
D
D
Hamulyák
K
K
Petersen
L C
LC
Spronk
H M H
HM
ten Cate
H
H
D000818:Animals; D015942:Factor VIIa / Q000008:administration & dosage / Q000494:pharmacology*; D007249:Inflammation; D051379:Mice; D017202:Myocardial Ischemia / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000517:prevention & control*; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics
D016328:NF-kappa B; D012333:RNA, Messenger; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D015942:Factor VIIa