Project description:Heart disease remains the leading cause of death globally. Although reperfusion following myocardial ischemia can prevent death by restoring nutrient flow, ischemia/reperfusion injury can cause significant heart damage. The mechanisms that drive ischemia/reperfusion injury are not well understood; currently, few methods can predict the state of the cardiac muscle cell and its metabolic conditions during ischemia. Here, we explored the energetic sustainability of cardiomyocytes, using a model for cellular metabolism to predict the levels of ATP following hypoxia. We modeled glycolytic metabolism with a system of coupled ordinary differential equations describing the individual metabolic reactions within the cardiomyocyte over time. Reduced oxygen levels and ATP consumption rates were simulated to characterize metabolite responses to ischemia. By tracking biochemical species within the cell, our model enables prediction of the cell’s condition up to the moment of reperfusion. The simulations revealed a distinct transition between energetically sustainable and unsustainable ATP concentrations for various energetic demands. Our model illustrates how even low oxygen concentrations allow the cell to perform essential functions. We found that the oxygen level required for a sustainable level of ATP increases roughly linearly with the ATP consumption rate. An extracellular O2 concentration of ~0.007 mM could supply basic energy needs in non-beating cardiomyocytes, suggesting that increased collateral circulation may provide an important source of oxygen to sustain the cardiomyocyte during extended ischemia. Our model provides a time-dependent framework for studying various intervention strategies to change the outcome of reperfusion.
Project description:Profile the microRNA expression in the Gracilis muscle of rat after 4h ischemia and 24 h reperfusion Following 4 h of ischemia and subsequent reperfusion for 4 h of the gracilis muscles, the specimens were analyzed with an Agilent rat miRNA array to detect the expressed miRNAs in the experimental muscles compared to those from the sham-operated controls. Two-condition experiment, Gracilis muscle after 4h ischemia and reperfusion injury for 24 h v.s. Gracilis muscle (sham control), Biological replicates: 2 control replicates, 2 experiement replicates
Project description:Ischemia-reperfusion injury (IRI) is a major cause of morbidity and mortality following conventional lung transplantation and warm ischemia may limit success of transplanting lungs from non-heart-beating donors. We sought to determine alterations in gene expression in rat lung tissue subjected to warm ischemia in vivo followed by reperfusion. Keywords: time course
Project description:The purpose of the present study was to investigate time-dependent changes in gene expression, following induction of IR in the rat retina, and to characterize the affected pathways, networks and processes. 6 biological replicates with two treatments (Sham control and Ischemia reperfusion) and 3 time points (0h, 24h and 7day)
Project description:Transcriptional profiling of rat gracilis muscle after ischemia 4h and reperfusion for 1d, 3d, 7d and 14d v.s. sham control, and correlate the downregulated transcripts to the computational predicted gene targets of ron-miR-21 Following 4 h of ischemia and subsequent reperfusion for 4 h of the gracilis muscles, three miRNAs (miR-21, miR-200c, and miR-205) of 350 tested rat miRNAs were found to have an increased expression in the miRNA array.The expression of the mRNA in the muscle specimens after 4 h of ischemia and reperfusion for 1, 3, 7, and 14 d were detected with the Agilent Whole Rat Genome 4 Ã 44 k oligo microarray. A combined approach using a computational prediction algorithm that included miRanda, PicTar, TargetScanS, MirTarget2, RNAhybrid, and the whole genome microarray experiment was performed by monitoring the mRNA:miRNA association to identify potential target genes. Four-condition experiment, Gracilis muscle after ischemia-reperfusion injury for 1d, 3d, 7d and 14d v.s.Gracilis muscle (sham control), Biological replicates: 1 control replicate, 1 experiement replicate (each condition).
Project description:Ischemic preconditioning is effective in limiting subsequent ischemic acute kidney injury in experimental models. microRNAs are an important class of post-transcriptional regulator and show promise as biomarkers of kidney injury. An evaluation was performed of the time- and dose-dependent effects of ischemic preconditioning in a rat model of functional (bilateral) ischemia-reperfusion injury. A short, repetitive sequence of ischemic preconditioning resulted in optimal protection from subsequent ischemia-reperfusion injury. A detailed characterization of microRNA expression in ischemic preconditioning/ischemia-reperfusion injury was performed by small RNA-Seq.