Project description:Ischemia reperfusion (I/R) injury is an unavoidable event occurring during heart transplantation, leading to graft failures and lower long-term survival rate of the recipient. microRNAs are major regulators of genes. IR causes apoptosis/death of cardiomyocytes, resulting from up-regulation of apoptotic genes and down-regulation of anti-apoptotic genes which are regulated by microRNA. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. We perserved donor hearts with university of Wisconsin solution for 18h at 4C degree before being implanted into recipients to create ischemia reperfusion injury. The preserved hearts were implanted into a syngeneic recipient mice. 24h after transplantation, heart grafts were harvested for microRNA extraction.
Project description:Hepatic ischemia reperfusion injury is a dynamic process consisting of two stages: ischemia and reperfusion, and triggers a cascade of physiological and biochemical events. Given the important role of microRNAs in regulating gene expression, we analyzed gene expression changes in mouse livers at sham control, ischemia stage, and reperfusion stage. We generated global expression profiles of microRNA and mRNA genes in mouse livers subjected to ischemia reperfusion injury at the three stages, respectively. Comparison analysis showed that reperfusion injury had a distinct expression profile whereas the ischemia sample and the sham control were clustered together. Consistently, there are 69 differentially expressed microRNAs between the reperfusion sample and the sham control whereas 28 differentially expressed microRNAs between the ischemia sample and the sham control. We further identified two modes of microRNA expression changes in ischemia reperfusion injury. Functional analysis of both the differentially expressed microRNAs in the two modes and their target mRNAs revealed that ischemia injury impaired mitochondria function, nutrient consumption, and metabolism process. In contrast, reperfusion injury led to severe tissue inflammation that is predominantly an innate-immune response in the ischemia reperfusion process. Our staged analysis of gene expression profiles provides new insights into regulatory mechanisms of microRNAs in mouse hepatic ischemia reperfusion injury.
Project description:Ischemia reperfusion (I/R) injury is an unavoidable event occurring during heart transplantation, leading to graft failures and lower long-term survival rate of the recipient. IR causes apoptosis / death of cardiomyocytes, resulting from up-regulation of apoptotic genes and down-regulation of anti-apoptotic genes. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. We used microarrays to detect gene expression profile of ischemia reperfusion injured hearts and identified distinct classes of up-regulated and down regulated genes during this I/R.
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: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:Hepatic ischemia reperfusion injury is a dynamic process consisting of two stages: ischemia and reperfusion, and triggers a cascade of physiological and biochemical events. Given the important role of microRNAs in regulating gene expression, we analyzed gene expression changes in mouse livers at sham control, ischemia stage, and reperfusion stage. We generated global expression profiles of microRNA and mRNA genes in mouse livers subjected to ischemia reperfusion injury at the three stages, respectively. Comparison analysis showed that reperfusion injury had a distinct expression profile whereas the ischemia sample and the sham control were clustered together. Consistently, there are 69 differentially expressed microRNAs between the reperfusion sample and the sham control whereas 28 differentially expressed microRNAs between the ischemia sample and the sham control. We further identified two modes of microRNA expression changes in ischemia reperfusion injury. Functional analysis of both the differentially expressed microRNAs in the two modes and their target mRNAs revealed that ischemia injury impaired mitochondria function, nutrient consumption, and metabolism process. In contrast, reperfusion injury led to severe tissue inflammation that is predominantly an innate-immune response in the ischemia reperfusion process. Our staged analysis of gene expression profiles provides new insights into regulatory mechanisms of microRNAs in mouse hepatic ischemia reperfusion injury.
Project description:Ischemia reperfusion (I/R) injury is an unavoidable event occurring during heart transplantation, leading to graft failures and lower long-term survival rate of the recipient. microRNAs are major regulators of genes. IR causes apoptosis/death of cardiomyocytes, resulting from up-regulation of apoptotic genes and down-regulation of anti-apoptotic genes which are regulated by microRNA. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process.
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 Exiqon miRCURY microRNA array.
Project description:This SuperSeries is composed of the following subset Series: GSE21405: MicroRNA Profiling In Ischemia-Reperfusion Injury Of The Gracilis Muscle In Rats GSE21406: Potential Target Genes of MicroRNA-21 In Ischemia-Reperfusion Injury Of The Gracilis Muscle In Rats Refer to individual Series