Project description:Ischemia/reperfusion injury (IRI) has a major impact on the long-term outcome of renal allografts. However, the mechanisms of IRI related to chronic allograft nephropathy (CAN) are still poorly understood. To address this issue, in a F344 to Lewis transplantation model of the rat, kidneys were either subjected to 20 min. or 24 hours of cold ischemia. A customized cDNA microarray representing 737 immune related genes was used for gene expression analysis after 12 hours and 6 months of engraftment. Thereby showing the 6-month graft function and histology were only moderately deteriorated following short cold ischemic time (20 min.), while prolonged ischemia (24 hrs) accelerated CAN development. Following prolonged cold ischemia already 12 hrs after engraftment about 30 genes were differentially expressed up to >20-fold. This included adhesion molecules, heat shock proteins, transcription factors and chemokines (CXCL10) associated with a strong CD68+ macrophage infiltration. Furthermore we observed a remarkable up-regulation of immunoproteasomes implying a re-organisation of the proteasome complex. This data might explain the higher incidence of alloreactivity following enhanced IRI. After 6 months, the prolonged cold ischemia of 24 hours revealed the significant induction of 4 genes: clusterin, C4, and the CCR7 ligands CCL19/21. This supported the observation of enhanced vasculopathy, humoral alloreactivity and increased tracking of MHC-II+ antigen presenting cells during CAN suggesting them as suitable novel targets for combating IRI. Keywords: transplantation, cold ischemia, inflammation, gene expression profiling
Project description:Ischemia/reperfusion injury (IRI) has a major impact on the long-term outcome of renal allografts. However, the mechanisms of IRI related to chronic allograft nephropathy (CAN) are still poorly understood. To address this issue, in a F344 to Lewis transplantation model of the rat, kidneys were either subjected to 20 min. or 24 hours of cold ischemia. A customized cDNA microarray representing 737 immune related genes was used for gene expression analysis after 12 hours and 6 months of engraftment. Thereby showing the 6-month graft function and histology were only moderately deteriorated following short cold ischemic time (20 min.), while prolonged ischemia (24 hrs) accelerated CAN development. Following prolonged cold ischemia already 12 hrs after engraftment about 30 genes were differentially expressed up to >20-fold. This included adhesion molecules, heat shock proteins, transcription factors and chemokines (CXCL10) associated with a strong CD68+ macrophage infiltration. Furthermore we observed a remarkable up-regulation of immunoproteasomes implying a re-organisation of the proteasome complex. This data might explain the higher incidence of alloreactivity following enhanced IRI. After 6 months, the prolonged cold ischemia of 24 hours revealed the significant induction of 4 genes: clusterin, C4, and the CCR7 ligands CCL19/21. This supported the observation of enhanced vasculopathy, humoral alloreactivity and increased tracking of MHC-II+ antigen presenting cells during CAN suggesting them as suitable novel targets for combating IRI. Keywords: transplantation, cold ischemia, inflammation, gene expression profiling Renal allografts from F344 donors were transplanted into unmodified LEW recipients. Before harvesting, grafts were perfused with University of Wisconsin solution at 4°C undergoing 20 min. (group A) or 24 hrs (group B) cold ischemia. Engrafted organs were either removed after 12 hrs (group I-A (n=3) and I-B (n=2)) or after 6 months (group II-A (n=3) and II-B (n=2)). Recipient animals of the group II received CyA treatment for 10 days at a dosage of 1.5 mg/kg. Untreated normal kidneys from F344 rats served as control. RNA from transplanted and untreated (control) rat kidneys were labeled by reverse transcription with Cy5 and Cy3 fluorescence, respectively.
Project description:Cold ischemia-reperfusion induced injury contributes to poor lung transplant outcomes. We used transcriptome sequencing to study the biological response of mouse lungs to the cold ischemia-reperfusion process. Mouse orthotopic left LTx was performed with standard cuff techniques. Briefly, the donor lungs were recovered after being flushed with 10ml low potassium dextran (LPD) solution and inflated with 50% oxygen. Cold ischemia was induced by storing donor lungs in 20ml LPD at 4°C for 24 hours. Then, the left donor lung was cuffed and implanted into recipients within 45 minutes. After the 4-hour reperfusion, the recipient mice were sacrificed and the transplanted lungs were collected.
Project description:<br><br>Annual heart allograft failure in humans rates about 3-5%. The main reason after the first postoperative year is chronic rejection. Myointimal hyperplasia, the hellmark of chronic rejection, results in a specific type of ischemic heart disease. The lack of angina pectoris symptoms allow ventricular arrythmias, sudden cardiac death or heart failure to occur without warning. In addition, diagnostic tools such as endomyocardial biopsy, coronary angiography or intracoronary ultrasound fail to predict the individual risk for myocardial dysfunction.<br><br>The mechanisms responsible for chronic rejection are predominantly alloimmune mediated with activated T cells, macrophages, B cell mediated antibody formation and secreted cytokines responding to HLA and other endothelial cell antigens. In addition, non immunologic risk factors such as recipient age, metabolic factors, hypertension and ischemia contribute to development of this disease. Previous studies have demonstrated that ischemia has a profound influence on short term allograft survival but the underlaying mechanisms remain largely unknown. Apoptosis seems to play a crucial role in ischemia/reperfusion injury and several mechanisms for programmed cell death have been described. However, consequences on long term cell function of viability have not been investigated. <br><br>The aim of this study was to investigate the implication and the mechanism of prolonged cold organ storage as a non immunologic risk factor in the pathogenesis of chronic rejection in a cardiac allograft model. <br><br>We aimed for answering the following specific questions:<br><br>How does cold ischemia affect the alloimmue response short and long term? <br><br>How does prolonged cold ischemia affect gene expression at later time points after transplantation? <br><br>Does it influence gene expression during chronic rejection?<br><br><br><br>
Project description:We carried out the transcriptome analysis to explore expression profiles differences and identify the key genes involved in pear seed dormancy release, by comparing callery pear (Pyrus calleryana Decne) seeds at three different stages of cold stratification
Project description:Time course experiments involving bilateral renal ischemia reperfusion injury (IRI) in C57BL/6J mice (0 hr control, 20 min bilateral ischemia without reperfusion, 4, 16, 24, 36, 48, and 72 hrs post IRI). This dataset also includes IRI at 48 hrs and 72 hrs in Azin1 A-to-I locked and Azin1 A-to-I uneditable mice.
Project description:The control of pre-analytical-factors in human biospecimens collected for health research is currently required. Only two previous reports using post-mortem brain samples have tried to address the impact of cold-ischemia on tissue pH. Here we report pH variations according to time (third-order polynomial model) in mice for liver, kidney and lung samples. Tissue alkalosis in cold-ischemia time may be an underlying mechanism of gene expression changes. Therefore, tissue-pH regulation after organ removal may minimize biological stress in human tissue samples.
Project description:The purpose of the present study was to investigate time-dependent changes in the expression profile of miRNAs, 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 5 time points (0h, 2h, 24h, 48h and 7day) with total of 60 samples.