Prolonged Cold Preservation Research Articles

Cellular Cytosolic Energy Replenishment Increases Vascularized Composite Tissue Tolerance to Extended Cold Ischemia Time.

Vascularized composite allotransplantation (VCA) is a restorative surgical procedure to treat whole or partially disfiguring craniofacial or limb injuries. The routine clinical use of this VCA surgery is limited using compromised allografts from deceased donors and by the failure of the current hypothermic preservation protocols to extend the allograft's cold ischemia time beyond 4 h. We hypothesized that the active replenishment of the cellular cytosolic adenosine-5`-triphosphate (ATP) stores by means of energy delivery vehicles (ATPv) encapsulating high-energy ATP is a better strategy to improve allograft's tolerance to extended cold ischemia times. We utilized established rat model of isolated bilateral in-situ non-cycled perfusions of both hind limbs. Ipsilateral and contralateral limbs in the anesthetized animal were randomized for simultaneous perfusions with either the University of Wisconsin (UW) solution, with/without O2 supplementation (control), or with the UW solution supplemented with the ATPv, with/without O2 supplementation (experimental). Following perfusion, the hind limbs were surgically removed and stored at 4°C for 12, 16, or 24 hours as extended cold ischemia times. At the end of each respective storage time, samples of skin, and soleus, extensor digitalis longus, and tibialis anterior muscles were recovered for assessment using tissue histology and tissue lysate studies. Control muscle sections showed remarkable microvascular and muscle damage associated with loss of myocyte transverse striation and marked decrease in myocyte nucleus density. A total of 1,496 nuclei were counted in 179 sections of UW-perfused control muscles in contrast to 1,783 counted in 130 sections of paired experimental muscles perfused with the ATPv-enhanced perfusate. This yielded 8 and 13 nuclei/field for the control and experimental muscles, respectively (P < .004). Oxygenation of the perfusion solutions before use did not improve the nucleus density of either the control or experimental muscles (n = 7 animals, P > .05). Total protein isolated from the muscle lysates was similar in magnitude regardless of muscle type, perfusion protocol, or duration of cold ischemia time. Prolonged static cold preservation of the hind limbs completely degraded the composite tissue's Ribonucleic acid (RNA). This supplementary result confirms the notion that that reverse transcription-Polymerase Chain Reaction, enzyme-linked immunosorbent assay, or the respiratory complex II enzyme activity techniques should not be used as indices of graft quality after prolonged static cold storage. In conclusion, this study demonstrates that active cellular cytosolic ATP replenishment increases hind limb composite tissue tolerance to extended cold ischemia times. Quality indicators and clinically relevant biomarkers that define composite tissue viability and function during static cold storage are warranted.

5-Aminolevulinate improves metabolic recovery and cell survival of the liver following cold preservation.

Rationale: Hibernating thirteen-lined ground squirrels (GS; Ictidomys tridecemlineatus) are naturally adapted to prolonged periods of ultraprofound hypothermia (body temperature < 5 ºC) during torpor, and drastic oscillations of body temperature and ischemia/reperfusion-like stress during their short euthermic interbout arousals. Thus, their superior adaptability may hold tremendous promise for the advancement of donor organ cold preservation and subsequent organ transplantation. However, bridging hibernation research and translational medicine has been impeded by a dearth of in vitro research tools, till the recent establishment of the GS induced pluripotent stem cells (iPSCs). In this study, we reported the generation of functional hepatocyte-like cells (HLCs) from GS iPSCs. As temperature and oxygen supply affect cellular metabolism, we hypothesized that the GS HLCs can metabolically counter drastic temperature and oxygen supply changes. Differentially regulated metabolites can be evaluated and included into the preservation solution to mitigate temperature and ischemia/reperfusion-associated damage to donor livers.Methods: A protocol has been developed to produce GS iPSCs-derived HLCs. Comparative metabolomic analysis on GS HLCs and human donor liver samples revealed changes in metabolites caused by cold storage and rewarming. Human embryonic stem cell (ESC)-derived HLCs and ex vivo cold preservation and reperfusion of isolated rat livers were used to assess candidate metabolites that may have protective effects against preservation-related injuries.Results: GS iPSCs were efficiently differentiated into expandable, cryopreservation-compatible and functional HLCs. Metabolomic analysis unveiled distinct changes of mitochondrial metabolites between GS and human cells following cold storage and rewarming. GS and human HLC-based experiments indicated that the metabolism of 5-aminolevulinate (5-ALA) is key to restricting free radical production during rewarming. Survival of human HLCs was significantly increased following cold exposure and rewarming, as supplemented 5-ALA enhanced Complex III activity and improved mitochondrial respiration. Further, 5-ALA mitigated damage in rat livers following 48-h cold preservation and ex vivo reperfusion. Metabolomic and transcriptomic analyses revealed that supplemented 5-ALA promoted both anabolic and catabolic activities while alleviating cell death, inflammation, hypoxia and other stress responses in isolated perfused rat livers.Conclusion: In the liver, rewarming from ultraprofound hypothermia imposes complex metabolic challenges and stresses on the mitochondria. Metabolites such as 5-ALA can help alleviate mitochondrial stress. Supplementing 5-ALA to the liver preservation solution can substantially improve the functional recovery of rat livers following prolonged cold preservation, rewarming and reperfusion.

Custodiol-N Is Superior to Custodiol® Solution in Experimental Rat Uterus Preservation.

Uterus transplantation (UTx) is the first and only available treatment for women with absolute uterine factor infertility. However, clinical application is limited by the lack of organs, ischemia/reperfusion injury, as well as immunosuppression after UTx. Several different preservation solutions are used in experimental and clinical UTx, including Custodiol® solution. Recently, the novel Custodiol-N solution was developed with superior results in organ preservation. However, the solution was not tested yet in UTx. Therefore, the aims of this study were to evaluate the effect of Custodiol-N in uterus prolonged cold preservation time (8 and 24 h), compared to Custodiol® solution. Uterus tissue samples were obtained from adult Sprague Dawley rats (n = 10/group). Cold ischemic injury was estimated by histology, including immunohistochemistry, and biochemical tissue analyses. After 8 h of cold ischemia, higher percentage of tissue edema, necrosis signs and myeloperoxidase expression, as well as lower superoxide dismutase activity were found in Custodiol® compared to Custodiol-N (p < 0.05). These differences were more pronounced after 24 h of cold preservation time (p < 0.05). This study demonstrated that Custodiol-N protects uterus grafts from cold ischemic injury better than standard Custodiol® most likely via inhibition of oxidative stress and tissue edema. It seems that iron chelators in the composition of Custodiol-N play an important protective role against cold ischemia.

Myocardial protection by propolis during prolonged hypothermic preservation

Oxidative stress is involved in the pathogenesis of ischemia-reperfusion during myocardial transplantation. Therefore, graft preservation solutions may be improved by supplementation with antioxidants to minimize graft dysfunction caused by cold ischemic injury. Propolis is a polyphenol-rich substance which has an important antioxidant activity. The protective effect of propolis against oxidative stress induced by prolonged cold preservation of heart was investigated. Mice were subjected to a hypothermic model of ischemia in which hearts were preserved for 24 h at 4 °C in Krebs-Hensleit (KH) solution in the absence or presence of propolis concentrations (50, 150 and 250 μg/ml). Levels of released Lactate dehydrogenase (LDH), Creatine phosphokinase (CPK) and Troponine-I (Trop I) were assessed in the preservation solution and histological assessement of heart ischemia injuries was performed. Oxidative stress biomarkers malondialdehyde (MDA) and advanced oxidation protein products (AOPP) and antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were assessed in cardiac tissue. Mitochondria were isolated from stored hearts and production of reactive oxygen species (ROS) was tested. Propolis supplementation protected efficiently hearts during preservation by reducing significantly levels of lipids and proteins oxidation and restoring activities of antioxidant enzymes. Also, propolis preserved tissue integrity altered by hypothermic ischemia in a concentration-dependent manner. Propolis reduced significantly the rate of H2O2 produced by mitochondrial respiration, the best antioxidant effect being obtained at the highest propolis concentration (250 μg/ml). Algerian propolis is a non-temperature sensitive scavenger that protects heart from oxidative damage induced by prolonged hypothermic ischemia.

Direct comparison of the infarct-limiting and hemodynamic effects of various necroptosis inhibitors in the model of prolonged static cold storage of the donor rat heart

Objective . To investigate the effects of various necroptosis inhibitors on the morphological and functional characteristics of the myocardium in the model of prolonged cold preservation of the donor rat heart. Design and methods. Thirty eight Wistar rats were divided into the following groups: 1) control (n = 7), 2) dimethylsulfoxide (DMSO) (n = 7), 3) necrostatin-1s (n = 6), 4) necrosulfonamide (n = 6), 5) necrostatin-5 (n = 6), 6) necrostatin-1 (n = 6). Necroptosis inhibitors were administered by intraperitoneal injection 1 hour prior to the start of the experiment, previously dissolved in DMSO. HTK solution cooled to 4 °C was used as a preservative solution. The functional state of the myocardium was assessed by continuous recording of intraventricular pressure, heart rate and coronary flow velocity. Morphological changes in the myocardium were assessed by the size of myocardial necrosis, measured planimetrically after the end of 8-hour ischemia and 2-hour reperfusion. Results. All investigated necroptosis inhibitors significantly improved the morphological and functional state of the myocardium, which manifested itself in a significantly smaller amount of myocardial necrosis in the groups of necroptotic inhibitors in comparison with control groups and DMSO. Thus, in the groups of necrosulfonamide and necrostatin-1s, myocardial necrosis size was 31 ± 8,7 % and 27 ± 8,2 %, respectively; in necrostatin-5 and necrostatin-1 groups — 37 ± 9,2 % and 34 ± 7,8, respectively, which is lower than in control groups and DMSO (58 ± 8,6 % and 60 ± 7,6 %, respectively, p < 0,05). Also, diastolic intraventricular pressure was lower and pulse intraventricular pressure and coronary flow velocity were higher during the reperfusion period in the groups of necroptosis inhibitors compared to control group and DMSO group (p < 0,05). We did not find any significant differences between necroptosis inhibitors regarding cardioprotective activity in the model of prolonged cold preservation of the donor heart. Conclusions. All inhibitors of necroptosis equally improved the morphological and functional state of the myocardium in the model of prolonged static cold storage of the donor heart.

CARDIOPROTECTIVE EFFECTS OF NECROSTATIN‑1S AND NECROSULFONAMIDE IN THE MODEL OF PROLONGED STATIC COLD STORAGE OF THE DONOR RAT HEART

Objective . To investigate the effects of necroptosis inhibitors — necrosulfonamide and necrostatin‑1s — on morphofunctional characteristics of the myocardium in the model of prolonged cold preservation of the donor rat heart. Design and methods . The study was performed on 27 Wistar rats. The animals were divided into the following groups: 1) control (n = 7), 2) dimethylsulfoxide (DMSO, n = 6), 3) necrostatin‑1s (n = 8), 4) necrosulfonamide (n = 6). All test compounds were administered intraperitoneally 1 hour before the start of the experiment. Histidine-tryptophan-ketoglutarate (HTK) solution cooled to 4 °C was used as a preservative agent. DMSO was used as a solvent for necrostatin‑1s and necrosulfonamide. During the experiment, left ventricular pressure, heart rate and coronary flow were recorded. At the end of 8‑hour of ischemia and 2‑hour of reperfusion, myocardial infarct size was planimetrically evaluated. Results . Necrostatin-1s and necrosulfonamide show cardioprotective effects, as evidenced by the significantly lower levels of myocardial necrosis in these groups, as well as the best indices of intracardiac hemodynamics during reperfusion. In the groups of necrosulfonamide and necrostatin‑1s, myocardial infarct size was 32,2 ± 9,6 and 29,0 ± 9,2 %, respectively, which is significantly lower than in control groups and DMSO (54,4 ± 6,6 and 59,2 ± 5,6 %, respectively, p < 0,05). During reperfusion in necrosulfonamide and necrostatin‑1s groups, higher values of pulse intraventricular pressure and coronary flow rates were recorded, as well as lower diastolic intraventricular pressure, compared to control group and DMSO (p < 0,05). Conclusions . Necroptosis inhibitors necrostatin‑1s and necrosulfonamide improve morphofunctional characteristics of the myocardium state during prolonged cold preservation of the donor heart.

Hydrogen Gas Ameliorates Hepatic Reperfusion Injury After Prolonged Cold Preservation in Isolated Perfused Rat Liver.

Hydrogen gas reduces ischemia and reperfusion injury (IRI) in the liver and other organs. However, the precise mechanism remains elusive. We investigated whether hydrogen gas ameliorated hepatic I/R injury after cold preservation. Rat liver was subjected to 48-h cold storage in University of Wisconsin solution. The graft was reperfused with oxygenated buffer with or without hydrogen at 37° for 90 min on an isolated perfusion apparatus, comprising the H2 (+) and H2 (-) groups, respectively. In the control group (CT), grafts were reperfused immediately without preservation. Graft function, injury, and circulatory status were assessed throughout the perfusion. Tissue samples at the end of perfusion were collected to determine histopathology, oxidative stress, and apoptosis. In the H2 (-) group, IRI was indicated by a higher aspartate aminotransferase (AST), alanine aminotransferase (ALT) leakage, portal resistance, 8-hydroxy-2-deoxyguanosine-positive cell rate, apoptotic index, and endothelial endothelin-1 expression, together with reduced bile production, oxygen consumption, and GSH/GSSG ratio (vs. CT). In the H2 (+) group, these harmful changes were significantly suppressed [vs. H2 (-)]. Hydrogen gas reduced hepatic reperfusion injury after prolonged cold preservation via the maintenance of portal flow, by protecting mitochondrial function during the early phase of reperfusion, and via the suppression of oxidative stress and inflammatory cascades thereafter.

Ex vivo lung perfusion with adenosine A2A receptor agonist allows prolonged cold preservation of lungs donated after cardiac death

ObjectiveEx vivo lung perfusion has been successful in the assessment of marginal donor lungs, including donation after cardiac death (DCD) donor lungs. Ex vivo lung perfusion also represents a unique platform for targeted drug delivery. We sought to determine whether ischemia-reperfusion injury would be decreased after transplantation of DCD donor lungs subjected to prolonged cold preservation and treated with an adenosine A2A receptor agonist during ex vivo lung perfusion. MethodsPorcine DCD donor lungs were preserved at 4°C for 12 hours and underwent ex vivo lung perfusion for 4 hours. Left lungs were then transplanted and reperfused for 4 hours. Three groups (n = 4/group) were randomized according to treatment with the adenosine A2A receptor agonist ATL-1223 or the dimethyl sulfoxide vehicle: Infusion of dimethyl sulfoxide during ex vivo lung perfusion and reperfusion (DMSO), infusion of ATL-1223 during ex vivo lung perfusion and dimethyl sulfoxide during reperfusion (ATL-E), and infusion of ATL-1223 during ex vivo lung perfusion and reperfusion (ATL-E/R). Final Pao2/Fio2 ratios (arterial oxygen partial pressure/fraction of inspired oxygen) were determined from samples obtained from the left superior and inferior pulmonary veins. ResultsFinal Pao2/Fio2 ratios in the ATL-E/R group (430.1 ± 26.4 mm Hg) were similar to final Pao2/Fio2 ratios in the ATL-E group (413.6 ± 18.8 mm Hg), but both treated groups had significantly higher final Pao2/Fio2 ratios compared with the dimethyl sulfoxide group (84.8 ± 17.7 mm Hg). Low oxygenation gradients during ex vivo lung perfusion did not preclude superior oxygenation capacity during reperfusion. ConclusionsAfter prolonged cold preservation, treatment of DCD donor lungs with an adenosine A2A receptor agonist during ex vivo lung perfusion enabled Pao2/Fio2 ratios greater than 400 mm Hg after transplantation in a preclinical porcine model. Pulmonary function during ex vivo lung perfusion was not predictive of outcomes after transplantation.

The mitochondria-targeted anti-oxidant MitoQ decreases ischemia-reperfusion injury in a murine syngeneic heart transplant model

BackgroundFree radical production and mitochondrial dysfunction during cardiac graft reperfusion is a major factor in post-transplant ischemia-reperfusion (IR) injury, an important underlying cause of primary graft dysfunction. We therefore assessed the efficacy of the mitochondria-targeted anti-oxidant MitoQ in reducing IR injury in a murine heterotopic cardiac transplant model.MethodsHearts from C57BL/6 donor mice were flushed with storage solution alone, solution containing the anti-oxidant MitoQ, or solution containing the non–anti-oxidant decyltriphenylphosphonium control and exposed to short (30 minutes) or prolonged (4 hour) cold preservation before transplantation. Grafts were transplanted into C57BL/6 recipients and analyzed for mitochondrial reactive oxygen species production, oxidative damage, serum troponin, beating score, and inflammatory markers 120 minutes or 24 hours post-transplant.ResultsMitoQ was taken up by the heart during cold storage. Prolonged cold preservation of donor hearts before IR increased IR injury (troponin I, beating score) and mitochondrial reactive oxygen species, mitochondrial DNA damage, protein carbonyls, and pro-inflammatory cytokine release 24 hours after transplant. Administration of MitoQ to the donor heart in the storage solution protected against this IR injury by blocking graft oxidative damage and dampening the early pro-inflammatory response in the recipient.ConclusionsIR after heart transplantation results in mitochondrial oxidative damage that is potentiated by cold ischemia. Supplementing donor graft perfusion with the anti-oxidant MitoQ before transplantation should be studied further to reduce IR-related free radical production, the innate immune response to IR injury, and subsequent donor cardiac injury.

Trps1 regulates biliary epithelial-mesenchymal transition and has roles during biliary fibrosis in liver grafts: a preliminary study.

ObjectiveTo investigate the role(s) of Trps1 in non-anastomotic biliary stricture (NABS) following liver transplantation.MethodsImmunohistochemical and histological techniques were used to detect Trps1, E-cadherin, CK19, vimentin, α-SMA, and collagen deposition. Human intrahepatic biliary epithelial cells (HIBECs) were infected with a Trps1 adenovirus, or transfected with Trps1 short-interfering RNAs (siRNAs). Reverse transcription polymerase chain reaction (RT-PCR) assays and western blotting were used to determine expression levels of epithelial and mesenchymal markers, and Trps1 in HIBECs.ResultsExpression of Trps1 and epithelial markers was down-regulated or absent in NABS liver samples. Mesenchymal markers were seen in biliary epithelial cells (BECs), with collagen deposited around the bile duct. Trps1 expression positively correlated with epithelial markers. Expression of epithelial marker mRNAs and proteins in HIBECs decreased with prolonged cold preservation (CP), while mesenchymal marker expression increased. A 12-h CP period led to increased Trps1 mRNA and protein levels. Expression of E-cadherin was increased in HIBECs following Trps1 adenovirus infection and CP/reperfusion injury (CPRI), with vimentin expression levels reduced and CPRI-mediated epithelial-mesenchymal transition (EMT) inhibited. Transfection of HIBECs with Trps1 siRNAs in conjunction with CPRI revealed that E-cadherin expression was decreased, vimentin expression was increased, and CPRI-mediated EMT was promoted.ConclusionTrps1 is involved in NABS pathogenesis following liver transplantation and negatively correlates with BEC EMT and biliary fibrosis in liver grafts. Trps1 demonstrates antagonistic effects that could reverse EMT.

Dopamine Treatment of Brain-Dead Fisher Rats Improves Renal Histology But Not Early Renal Function in Lewis Recipients After Prolonged Static Cold Storage

BackgroundBrain death (BD) and cold preservation are major risk factors for an unfavorable transplantation outcome. Although donor dopamine treatment in brain-dead rats improves renal function and histology in allogeneic recipients, it remains to be assessed if this also holds true for the combinations of BD and prolonged static cold preservation. MethodsBD was induced in F344 donor rats, which were subsequently treated with NaCl 1 mL/h (BD, n = 11), NaCl/hydroxy ethyl starch (BD-norm, n = 10), or 10 μg/min/kg dopamine (BD-dopa, n = 10). Renal grafts were harvested 4 h after BD and transplanted into bilateral nephrectomized Lewis recipients 6 h after cold preservation in University of Wisconsin solution. Renal function was evaluated by use of serum creatinine and urea concentrations at days 0, 1, 3, 5, and 10. Ten days after transplantation, recipients were killed and the renal allografts were processed for light microscopy and immune histology. ResultsSerum urea concentrations at days 5 and 10 were significantly lower in recipients that received a renal graft from dopamine-treated rats; for serum creatinine, only a trend was observed at day 10. Immune histology revealed a lower degree of ED1-positive cells in the donor dopamine-treated group. Under light microscopy, Banff classification revealed significantly less intimal arteritis in these grafts (P < .05). ConclusionsAlthough donor dopamine treatment clearly improves renal histology in this model, the beneficial effect on early renal function was marginal. It remains to be assessed if donor dopamine treatment has a beneficial effect on renal function in long-term follow-up.

Activation of Transient Receptor Potential Vanilloid Type 1 Channels by N-octanoyl Dopamine Improves Renal Function after Warm Ischemia but Not after Prolonged Cold Preservation.

Aim: N-octanoyl dopamine (NOD) improves renal function, when applied shortly before induction of acute kidney injury (AKI). It remains to be assessed how NOD convey its renoprotective properties, if NOD also protects after AKI induction, and if renal allograft recipients also benefit from NOD treatment. Methods: AKI was induced by clamping the left renal artery (45min) in unilateral nephrectomized Lewis or Spaque Dawley (SD), wild type (WT) and TRPV1-/- rats. Transplantations were performed in the Fisher to Lewis model using a standardized cold ischemia time of 20 hrs. Treatment was installed directly after restoration of organ perfusion. Renal function, histology and perfusion were assessed, by serum creatinine, microscopy and magnetic resonance imaging (MRI) using arterial spin labeling (ASL). Results: NOD significantly improved renal function in AKI in WT Lewis and SD rats, but not in TRPV1-/- SD rats. Improved renal function was paralleled by reduced renal inflammation, yet no differences were found in the expression of inflammatory mediators (adhesion molecules and cytokines). Although MRI-ASL showed a significant lower cortical perfusion in ischemic as compared to non-ischemic kidneys, no influence of NOD was observed. Even though prolonged cold storage did not abrogate TRPV1 activation by NOD, treatment of renal allograft recipients did not show a salutary effect. Conclusions: While NOD treatment improves renal function after warm ischemia induced AKI, it does not so after prolonged cold ischemia. Since the renoprotective effect of NOD depends on TRPV1 activation, it remains to be assessed why its salutary effect is lost after prolonged cold ischemia.

Pretreatment of the Donor with AICAR Significantly Protects Rat Heart Graft from Prolonged Cold Ischemia/Reperfusion Injury in an Isolated Model.

Purpose: To investigate whether pretreat donor rat with AMP-activated protein kinase (AMPK) activator AICAR can reduce heart graft injury after static, prolonged cold preservation and reperfusion in an isolated model. Methods: Eighteen Sprague-Dawley(SD) heart donor rats were equally divided into two groups: AICAR pretreatment group(AICAR group, n=9) and normal saline pretreatment group(Vehicle group, n=9). After the hearts were arrested with Histidine-Tryptophan-Ketoglutarate(HTK) solution, they were excised and preserved in HTK solution for 8 hours at 4 <sup style=“font-family: Arial, sans-serif;”>o[/sup]C. After cold preservation, hearts were reperfused for 1hr in an Langendorff model, concerned parameters were examined during and after reperfusion. Result: AICAR pretreated heart showed significantly higher left ventricular developing pressure(LVDP), heart rate(HR), coronary flow(CF) than vehicle pretreated group. Caspase 3 activity and percentage of TUNEL-positive cells were significantly reduced in AICAR pretreated group. Oxidative parameter 8-hydroxy-2′-deoxyguanosine(8-OHdG) and malondialdehyde (MDA) were also significantly decreased in AICAR pretreated group. Moreover, AICAR pretreatment significantly diminished cystolic cytochrome C release. Conclusion: Pretreatment of the donor with AICAR significantly protects heart grafts from prolonged cold ischemia/reperfusion injury. This protocol may be useful and feasible in clinical heart transplantation.

Global gene expression changes induced by prolonged cold ischemic stress and preservation method of breast cancer tissue

BackgroundTissue handling can alter global gene expression potentially affecting the analytical performance of genomic signatures, but such effects have not been systematically evaluated. MethodsTissue samples from 11 previously untreated breast tumors were minced and aliquots were either snap frozen or placed in RNAlater immediately or after 20, 40, 60, 120 or 180 min at room temperature. RNA was profiled on Affymetrix HG-U133A arrays. We used probe-set-wise hierarchical models to evaluate the effect of preservation method on transcript expression and linear mixed effects models to assess the effect of cold ischemic delay on the expression of individual probe sets. Gene set enrichment analysis identified pathways overrepresented in the affected transcripts. We combined the levels of 41 most sensitive transcripts to develop an index of ischemic stress. ResultsConcordance in global gene expression between the baseline and 40 min delay was higher for samples preserved in RNAlater (average concordance correlation coefficient CCC = 0.92 compared to 0.88 for snap frozen). Overall, 481 transcripts (3%) were significantly affected by the preservation method, most of them involved in processes important in cancer. Prolonged cold ischemic delay of up to 3 h induced marginal global gene expression changes (average CCC = 0.90 between baseline and 3 h delay). However 41 transcripts were significantly affected by cold ischemic delay. Among the induced transcripts were stress response genes, apoptotic response genes; among the downregulated were genes involved in metabolism, protein processing and cell cycle regulation. An index combining the expression levels of these genes was proportional to the cold ischemic delay. ConclusionsProlonged cold ischemia induces significant transcriptional changes in a small subset of transcripts in the tissue. Furthermore, the expression level of about 3% of the transcripts is affected by the preservation method. These sensitive transcripts should not be included in genomic signatures for more reliable analytical performance.

Pathological changes in primary cilia: A novel mechanism of graft cholangiopathy caused by prolonged cold preservation in a rat model of orthotopic liver transplantation.

To study the impairment of cholangiocyte primary cilia caused by prolonged cold preservation and its correlation with graft cholangiopathy after orthotopic liver transplantation (OLT). Subjects were 60 male Wistar rats that were divided into 2 groups: a control group (n = 30) receiving a donor liver preserved for 1 h and a study group (n = 30) receiving a donor liver preserved for 12 h. A two-cuff method was used to establish the OLT model, and the hepatic artery and bile ducts were reconstructed using stents. Samples were collected 2, 8, and 16 weeks after surgery, and 5 samples were collected from each group at each time point. Serum biochemical indicators were measured, morphological changes in intrahepatic bile ducts and cholangiocyte primary cilia were observed using an optical microscope and scanning electronic microscope, respectively, and the ciliary marker (α-tubulin) and membrane proteins (PC-1, TRPV4, and P2Y12) were detected using immunofluorescence analysis and Western blotting. In the study group, phlogocytes infiltrated around bile ducts and bile ducts proliferated markedly at 8 weeks. At 16 weeks, the biliary structures were indistinct and some bile ducts disappeared, a large amount of collagen was deposited, numerous phlogocytes infiltrated around ducts, some biliary epithelial cells (BECs) were deformed or dead, and primary cilia disappeared. In the control group, the intrahepatic bile ducts and BECs were nearly intact and the primary cilia were present. In the study group, the expression of α-tubulin, polycystin-1 (PC-1), TRPV4, and P2Y12 in bile ducts disappeared completely after 8 weeks. In the control group, expression of the marker and proteins decreased at 2 weeks and increased slightly after 8 weeks. These results suggest that the study group had dysfunctional primary cilia at the start of OLT and that this dysfunction was irreversible. In the control group, the primary cilia defects and subsequent biliary injury were temporary. Thus, prolonged cold preservation of a donor liver may cause graft cholangiopathy by altering the integrity and functions of cholangiocyte primary cilia.

A novel method of preserving cardiac grafts using a hydrogen-rich water bath

Exogenously administered hydrogen exerts cytoprotective effects through anti-oxidant, anti-inflammatory, and anti-apoptotic mechanisms in various disease settings, including organ transplantation. Our objective in this study was to evaluate the efficacy of a novel cold storage device equipped with a hydrogen-rich water bath. The study used an established rat heterotopic transplantation model. Syngeneic heart grafts from elderly donors (60- to 70-week-old Lewis rats) or allografts from adult donors (12-week-old Brown Norway rats) were exposed to prolonged cold preservation. The cardiac grafts were stored in plastic bags containing Celsior, which were immersed in the cold water bath equipped with an electrolyzer to saturate the water with hydrogen. The cardiac grafts then were heterotopically engrafted into Lewis rat recipients. In both experimental settings, serum troponin I and creatine phosphokinase were markedly elevated 3 hours after reperfusion in the control grafts without hydrogen treatment. The grafts exhibited prominent inflammatory responses, including neutrophil infiltration and the upregulation of messenger RNAs for pro-inflammatory cytokines and chemokines. Myocardial injury and inflammatory events were significantly attenuated by organ storage in the hydrogen-rich water bath. The grafts stored using the hydrogen-rich water bath also exhibited less mitochondrial damage and a higher adenosine triphosphate content. Hydrogen delivery to cardiac grafts during cold preservation using a novel hydrogen-supplemented water bath efficiently ameliorated myocardial injury due to cold ischemia and reperfusion. This new device to saturate organs with hydrogen during cold storage merits further investigation for possible therapeutic and preventative use during transplantation.

Protein Kinase C Inhibition Ameliorates Posttransplantation Preservation Injury in Rat Renal Transplants

Prolonged cold preservation frequently causes delayed renal graft function resulting from tubular epithelial injury. Inhibition of signal transduction downstream from protein kinase C (PKC) may reduce renal ischemia-reperfusion injury and confer renal graft protection. We therefore evaluated the effect of sotrastaurin, a small-molecule inhibitor of Ca²⁺-dependent and Ca²⁺-independent PKC isoforms, in comparison with mycophenolic acid (MPA) on rat renal transplants with prolonged cold preservation. Donor kidneys from male Lewis rats were cold stored in University of Wisconsin solution for 24 hr before syngeneic grafting. Recipients received sotrastaurin (30 mg/kg twice daily), MPA (20 mg/kg/day), or vehicle through gavage starting 1 hr after surgery. Renal function was evaluated by serum creatinine and histology on day 2 (acute injury) and day 7 (repair phase) after transplantation. Postreperfusion inflammation was determined by real-time polymerase chain reaction of proinflammatory genes and histology. Signaling mechanisms were studied by Western blotting and immunohistochemistry. Sotrastaurin enhanced immediate transplant function, attenuated epithelial injury, and accelerated renal function recovery compared with MPA. Despite the stronger anti-inflammatory capacity of MPA, only sotrastaurin treatment achieved significant cellular protection with persisting reduced apoptosis of tubular epithelial cells. Decreased phosphorylation of extracellular signal-regulated protein kinase and p66Shc adaptor protein, both involved in cellular stress and apoptosis, were likely the responsible mechanism of action. The PKC inhibitor sotrastaurin effectively ameliorated ischemia-reperfusion organ damage and promoted cytoprotection in a clinically relevant model of extended renal cold preservation followed by transplantation. Pharmacologic targeting of PKC may be beneficial for recipients receiving renal transplants at risk for delayed graft function.

The impact of prolonged cold preservation on the graft function and gene expression levels in an experimental lung transplantation model

Ischemia reperfusion injury (IRI) remains a significant cause of morbidity and mortality after lung transplantation. Early growth response-1 (EGR1) drives the expression of inflammatory mediators and has an important role in IRI. We hypothesized that the severe IRI caused by a long preservation induces a specific expression pattern of EGR1 and its target genes which would correlate with the lung graft function. SD rat lungs were preserved at 4 °C for 3 or 18 h, then transplanted and reperfused. Pulmonary grafts were evaluated for the blood gas oxygenation and pathological findings. The intra-graft mRNA levels of EGR1 and its downstream target genes were measured by real-time PCR. A Western blotting analysis of the EGR1 expression was used to validate the changes in the protein level. There was upregulation of EGR1, MIP-2 and PAI-1 when there was prolonged hypothermic preservation. The expression levels of MIP-2 and PAI-1 were observed to increase for up to 4 h in the 18 h preserved lungs. There were no differences in the expression levels of IL-1β and ICAM-1 between the lungs subjected to short and long periods of ischemia. Our data showed that prolonged hypothermic graft preservation deteriorates the pulmonary graft function, which was associated with the induction of EGR1 and its downstream target genes, which may aggravate IRI following lung transplantation.

Successful transplantation of rat hearts subjected to extended cold preservation with a novel preservation solution

Since prolonged cold preservation of the heart deteriorates the outcome of heart transplantation, a more protective preservation solution is required. We therefore developed a new solution, named Dsol, and examined whether Dsol, in comparison to UW, could better inhibit myocardial injury resulting from prolonged cold preservation. Syngeneic heterotopic heart transplantation in Lewis rats was performed after cold preservation with UW or Dsol for 24 or 36 h. In addition to graft survival, myocardial injury, ATP content, and Ca(2+) -dependent proteases activity were assessed in the 24-h preservation group. The cytosolic Ca(2+) concentration of H9c2 cardiomyocytes after 24-h cold preservation was assessed. Dsol significantly improved 7-day graft survival after 36-h preservation. After 24-h preservation, Dsol was associated with significantly faster recovery of ATP content and less activation of calpain and caspase-3 after reperfusion. Dsol diminished graft injury significantly, as revealed by the lower levels of infarction, apoptosis, serum LDH and AST release, and graft fibrosis at 7-day. Dsol significantly inhibited Ca(2+) overload during cold preservation. Dsol inhibited myocardial injury and improved graft survival by suppressing Ca(2+) overload during the preservation and the activation of Ca(2+) -dependent proteases. Dsol is therefore considered a better alternative to UW to ameliorate the outcome of heart transplantation.

Atorvastatin donor pre-treatment in a model of brain death and allogeneic kidney transplantation in rat

The aim of the present study was to evaluate the effect of donor pre-treatment with atorvastatin in a model of brain death followed by prolonged cold preservation and allogeneic kidney transplantation in rats. Donor rats were pre-treated with atorvastatin or vehicle 2 days prior to induction of brain death. After a brain death period of 6h kidneys were explanted and stored for 24 h at 4°C in UW solution and transplanted into allogeneic recipients. Non brain dead rats treated with vehicle were ventilated for 6h prior to explantation and served as controls. Grafts were harvested after 10 days. Donor treatment of brain dead organ donors with atorvastatin had no influence on renal histology (Banff score) or renal inflammation compared to vehicle treated brain dead rats 10 days after cold preservation and allogeneic transplantation. Grafts from brain dead organ donors showed severe signs of vasculopathy compared to grafts from non brain dead organ donors 10 days after prolonged cold preservation and allogeneic kidney transplantation. Kidneys harvested after brain death before cold preservation and allogeneic transplantation showed an increased infiltration of ED1 and MHCII positive cells compared to kidneys of non-brain dead animals (NBD). Atorvastatin donor pre-treatment of brain dead organ donors combined with 24h of cold preservation has no influence on graft rejection and infiltration with ED1 or MHCII positive cells in an allogeneic rat renal transplantation model. The detrimental combination of brain death and cold preservation might have overcome the possible protective effect of atorvastatin donor pre-treatment.