Rabbit heart can be "preconditioned" via transfer of coronary effluent.
Brief myocardial ischemia not only evokes a local cardioprotective or "preconditioning" effect but also can render remote myocardium resistant to sustained ischemia. We propose the following hypotheses: remote protection is initiated by a humoral trigger; brief ischemia-reperfusion will result in release of the humoral trigger (possibly adenosine and/or norepinephrine) into the coronary effluent; and transfer of this effluent to a virgin acceptor heart will elicit cardioprotection. To test these concepts, effluent was collected during normal perfusion from donor-control hearts and during preconditioning ischemia-reperfusion from donor-preconditioned (PC) hearts. After reoxygenation occurred and aliquots for measurement of adenosine and norepinephrine content were harvested, effluent was transfused to acceptor-control and acceptor-PC hearts. All hearts then underwent 40 min of global ischemia and 60 min of reperfusion, and infarct size was delineated by tetrazolium staining. Mean infarct size was smaller in both donor- and acceptor-PC groups (9% of left ventricle) than in donor- and acceptor-control groups (36% and 34%; P < 0.01). Protection in acceptor-PC hearts could not, however, be attributed to adenosine or norepinephrine. Thus preconditioning-induced cardioprotection can be transferred between rabbit hearts by transfusion of coronary effluent. Although adenosine and norepinephrine are apparently not responsible, these results suggest that remote protection is initiated by a humoral mechanism.
Dickson
E W
EW
Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA. eric.dickson@banyan.ummed.edu
Lorbar
M
M
Porcaro
W A
WA
Fenton
R A
RA
Reinhardt
C P
CP
Gysembergh
A
A
Przyklenk
K
K
D000241:Adenosine / Q000097:blood*; D000818:Animals; D001803:Blood Transfusion; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000502:physiology*; D066298:In Vitro Techniques; D019194:Ischemic Preconditioning / Q000379:methods*; D008955:Models, Cardiovascular; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control; D017202:Myocardial Ischemia / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D009638:Norepinephrine / Q000097:blood*; D010477:Perfusion; D011817:Rabbits; D013997:Time Factors; D016277:Ventricular Function, Left
D000241:Adenosine; D009638:Norepinephrine