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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, RESULTS. Meshes: Animals, Apoptosis, Aryl Hydrocarbon Receptor Nuclear Translocator, Caspase 8, Coronary Vessels, Deoxyuracil Nucleotides, Echocardiography, Heat-Shock Proteins, Ischemic Postconditioning, Myocardial Contraction, Myocardial Reperfusion Injury, Phosphatidylinositol 3-Kinases, Proteome, Proteomics, Proto-Oncogene Proteins c-bcl-2, Random Allocation, Receptors, Aryl Hydrocarbon, Signal Transduction, Sus scrofa, Systems Biology, TOR Serine-Threonine Kinases.
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Is reperfusion-triggered stress protein response in the myocardium blocked by post-conditioning . Systems biology pathway analysis highlights the key role of the canonical aryl-hydrocarbon receptor pathway? Context: Ischaemic post-conditioning (IPost-Co) exerts cardioprotection by diminishing ischaemia/reperfusion injury. Yet, the mechanisms involved in such protection remain largely unknown. We have investigated the effects of IPost-Co in cardiac cells and in heart performance using molecular, proteomic and functional approaches. Pigs underwent 1.5 h mid-left anterior descending balloon occlusion and then were sacrificed without reperfusion (ischaemia; n= 7), subjected to 2.5 h of cardiac reperfusion and sacrificed (n= 5); or subjected to IPost-Co before reperfusion and sacrificed 0.5 h (n= 4) and 2.5 h (n= 5) afterwards. A sham-operated group was included (n= 4). Ischaemic and non-ischaemic myocardium was obtained for molecular/histological analysis. Proteomic analysis was performed by two-dimensional electrophoresis followed by matrix-assisted laser desorption/ionization-time-of-flight identification. Potential protein networks involved were identified by bioinformatics and Ingenuity Pathway Analysis (IPA). Cardiac function was assessed by echocardiography. IPost-Co diminished (up to 2.5 h) reperfusion-induced apoptosis of both the intrinsic and extrinsic pathways whereas it did not affect reperfusion-induced Akt/mammalian target of rapamycin (mTOR)/P70S6K activation. Proteomic studies showed that IPost-Co reverted 43% of cardiac cytoplasmic protein changes observed during ischaemia and ischaemia + reperfusion. Systems biology assessment revealed significant changes in the aryl-hydrocarbon receptor (AhR) pathway (cell damage related). Bioinformatic data were confirmed since the expression of HSP90, AhR, ANRT, and β-tubulin (involved in AhR-signalling transduction) were accordingly modified after IPost-Co. IPost-Co rescued 52% of the left ventricle-at-risk compared with reperfusion alone and resulted in a ≈30% relative improvement in left ventricular ejection fraction (P <0.05).
assistant
IPost-Co improves cardiac function post-myocardial infarction and reduces reperfusion-induced cell damage by down-regulation of the AhR-signalling transduction pathway ultimately leading to infarct size reduction. Final Decision: yes