Cardiac remodelling hinders activation of cyclooxygenase-2, diminishing protection by delayed pharmacological preconditioning: role of HIF1 alpha and CREB.
OBJECTIVE
We tested whether delayed pharmacologic preconditioning elicited by isoflurane is protective in infarct-remodelled hearts.


RESULTS
Male Wistar rats were treated with the preconditioning drug isoflurane 6 weeks after permanent ligation of the left anterior descending coronary artery. Twenty-four and 48 h later, hearts were perfused on the Langendorff system and treated with cyclooxygenase-2 or 12-lipoxygenase inhibitors before exposure to 40 min of ischaemia followed by 90 min of reperfusion. Infarct size was determined by triphenyltetrazolium chloride staining and lactate dehydrogenase release. Cyclooxygenase-2 expression and activity were measured by Western blotting and colorimetric assay. Nuclear translocation of cyclooxygenase-2-inducing transcription factors HIF1alpha, CREB, STAT3, and NFkappaB was determined. Post-infarct, remodelled hearts exhibit alterations in cellular signalling, time course and extent of isoflurane-induced late protection. While remodelled, preconditioned hearts exhibited protection exclusively at 24 h, healthy hearts showed sustained protection for up to 48 h, which correlated with cyclooxygenase-2 protein expression and enzymatic activity. The cyclooxygenase-2 inhibitors celecoxib and NS-398, but not the 12-lipoxygenase inhibitor cinnamyl-3,4-dihydroxycyanocinnamate, abolished delayed protection in both healthy and remodelled hearts, identifying cyclooxygenase-2 as a key mediator of late protection in both models. Isoflurane induced nuclear translocation of HIF1alpha in all hearts, but CREB was exclusively activated in healthy but not remodelled myocardium, which expressed higher levels of the CREB antagonist ICER. Delayed protection by isoflurane in remodelled hearts was more vulnerable to inhibition by celecoxib.


CONCLUSIONS
Isoflurane failed to mobilize cyclooxygenase-2-inducing CREB in ICER-overexpressing, remodelled hearts, which was associated with a shortening of the second window of protection.
Feng
Jianhua
J
Cardiovascular Anesthesia Research Laboratory, Center of Clinical Research, Institute of Anesthesiology, E-HOF, University Hospital Zurich, Rämistrasse 100, Zurich CH-8091, Switzerland.
Lucchinetti
Eliana
E
Fischer
Gregor
G
Zhu
Min
M
Zaugg
Kathrin
K
Schaub
Marcus C
MC
Zaugg
Michael
M
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D015153:Blotting, Western; D002317:Cardiovascular Agents / Q000494:pharmacology*; D003124:Colorimetry; D051786:Cyclic AMP Response Element Modulator / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004195:Disease Models, Animal; D004789:Enzyme Activation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007530:Isoflurane / Q000494:pharmacology*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000201:enzymology / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050796:STAT3 Transcription Factor / Q000378:metabolism; D013997:Time Factors; D020257:Ventricular Remodeling
D002317:Cardiovascular Agents; C497412:Crem protein, rat; D017362:Cyclic AMP Response Element-Binding Protein; D016861:Cyclooxygenase Inhibitors; C497444:Hif1a protein, rat; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016859:Lipoxygenase Inhibitors; D016328:NF-kappa B; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D051786:Cyclic AMP Response Element Modulator; D007530:Isoflurane; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat