Normothermic Recirculation Research Articles

Long-term intraperitoneal access with description of a new access catheter.

Intraperitoneal chemotherapy can be administered as a single dose associated with hyperthermia (HIPEC) or in successive doses under normothermic conditions, such as early postoperative intraperitoneal chemotherapy (EPIC) or normothermic intraperitoneal chemotherapy (NIPEC or NIPEC-LT). Repetitive administration of intraperitoneal chemotherapy over a prolonged period may be associated with catheter-related complications, which are the primary cause of treatment interruption. This study aims to introduce and evaluate an innovative catheter system designed to mitigate these issues. Using a porcine experimental model, we tested a new catheter for long-term intraperitoneal access. Sixteen animals underwent catheter implantation followed by normothermic recirculation of peritoneal dialysis solution. Catheter functionality and any complications were monitored throughout successive treatment cycles. The new catheter system demonstrated optimal recirculation and maintained its functionality throughout successive treatments, without complications. Catheter replacement with a guidewire was successful, ensuring continued efficacy. The innovative catheter system shows promise in reducing complications and improving compliance in successive intraperitoneal chemotherapy doses, justifying further clinical trials to confirm its efficacy in patients.

Comparison of thermal variations in post-retrieval graft conditioning on rat livers.

Machine perfusion was found an effective tool to recover organ grafts from ischemic insults during preservation. It could be observed that organ integrity is significantly affected by abrupt temperature shifts during hypothermic storage and implantation periods. Studies showed that a gentle and controlled rise of the temperature during oxygenated machine perfusion prior to implantation can protect the tissue from reperfusion injury. Now, the possible role of temperature kinetics upon retrieval of the graft and prior to later cold storage should be investigated. Rat livers were retrieved after cardiac arrest and subjected to a brief ex situ machine perfusion with either hypothermic resuscitation (HR) at 8°C, near-normothermic resuscitation (NR) at 30°C or progressive resuscitation with lowering the temperature in a controlled fashion from 30°C to 8°C (PR). After cold storage (CS), liver functional parameters were evaluated by an established ex vivo reperfusion system. NR and PR resulted in significantly lower release of hepatic enzymes and less production of tumor necrosis factor upon reperfusion compared to CS while HR had a far less protective effect. An increase in bile production was only observed in the PR group, which also significantly increased the recovery of tissue adenosine triphosphate, the amount of which was, however, nearly paralleled by the NR protocol. Within the limitations of this model, it seems that normothermic recirculation appears to be a superior approach for the restitution of warm-ischemically injured liver grafts than immediate hypothermic machine perfusion.

Renal Warm Ischemia in Organ Donors After Circulatory Death

Chronic kidney disease is the most common type of organ failure worldwide, with a prevalence of 13.4% for all stages. Organ transplant is the only curative option for end-stage kidney failure. However, the shortage of organ donors remains a major obstacle in organ transplant, with donation after circulatory death being the most viable path to increasing the donor pool. The circumstances that surround this type of donation are different from donation after brain death, namely concerning warm ischemia times, which are longer and may preclude a successful transplant. This article describes the pathophysiology of warm ischemia and summarizes recent developments in technological and methodological practices that mitigate the mechanisms of warm ischemia. Anoxia, mitochondrial dysfunction, calcium overload, oxidative and nitrosative stress, immune response, and no reflow are the main mechanisms by which ischemia leads to cell death and organ dysfunction. In situ oxygenated recirculation, abdominal normothermic organ recirculation, abdominal hypothermic organ recirculation, and ex vivo machine perfusion ensure continued organ perfusion and prevent prolonged warm ischemia in organ donation. These practices, coupled with optimizations in the identification and assessment of potential donors after circulatory death, may lead to a significant increase in the number and success rates of organ transplant worldwide.

Defining the optimal duration for normothermic regional perfusion in the kidney donor: A porcine preclinical study.

Kidneys from donation after circulatory death (DCD) are highly sensitive to ischemia-reperfusion injury and thus require careful reconditioning, such as normothermic regional perfusion (NRP). However, the optimal NRP protocol remains to be characterized. NRP was modeled in a DCD porcine model (30minutes of cardiac arrest) for 2, 4, or 6hours compared to a control group (No-NRP); kidneys were machine-preserved and allotransplanted. NRP appeared to permit recovery from warm ischemia, possibly due to an increased expression of HIF1α-dependent survival pathway. At 2hours, blood levels of ischemic injury biomarkers increased: creatinine, lactate/pyruvate ratio, LDH, AST, NGAL, KIM-1, CD40 ligand, and soluble-tissue-factor. All these markers then decreased with time; however, AST, NGAL, and KIM-1 increased again at 6hours. Hemoglobin and platelets decreased at 6hours, after which the procedure became difficult to maintain. Regarding inflammation, active tissue-factor, cleaved PAR-2 and MCP-1 increased by 4-6hours, but not TNF-α and iNOS. Compared to No-NRP, NRP kidneys showed lower resistance during hypothermic machine perfusion (HMP), likely associated with pe-NRP eNOS activation. Kidneys transplanted after 4 and 6hours of NRP showed better function and outcome, compared to No-NRP. In conclusion, our results confirm the mechanistic benefits of NRP and highlight 4hours as its optimal duration, after which injury markers appear.

Uncontrolled donation after circulatory death: comparison of two kidney preservation protocols on graft outcomes

BackgroundKidney transplantation following uncontrolled donation after circulatory death (uDCD) presents a high risk of delayed graft function due to prolonged warm ischemia time. In order to minimise the effects of ischemia/reperfusion injury during warm ischemia, normothermic recirculation recently replaced in situ perfusion prior to implantation in several institutions. The aim of this study was to compare these preservation methods on kidney graft outcomes.MethodsThe primary endpoint was the one-year measured graft filtration rate (mGFR). We collected retrospective data from 64 consecutive uDCD recipients transplanted over a seven-year period in a single centre.ResultsThirty-two grafts were preserved by in situ perfusion and 32 by normothermic recirculation. The mean ± SD mGFR at 1 year post-transplantation was 43.0 ± 12.8 mL/min/1.73 m2 in the in situ perfusion group and 53.2 ± 12.8 mL/min/1.73 m2 in the normothermic recirculation group (p = 0.01). Estimated GFR levels were significantly higher in the normothermic recirculation group at 12 months (p = 0.01) and 24 months (p = 0.03) of follow-up. We did not find any difference between groups regarding patient and graft survival, delayed graft function, graft rejection, or interstitial fibrosis.ConclusionsFunction of grafts preserved by normothermic recirculation was better at 1 year and the results suggest that this persists at 2 years, although no difference was found in short-term outcomes. Despite the retrospective design, this study provides an additional argument in favour of normothermic recirculation.

Uncontrolled non-heartbeating donors (types I–II) with normothermic recirculation vs. heartbeating donors: Evaluation of functional results and survival

ObjectiveNon-heartbeating donors (NHBD) are an alternative to heartbeating donors (HBD). Our objective was to compare functional results and kidney survival from NHBDs and HBDs. Material and methodsA retrospective study comparing the results of 236 normothermically preserved kidneys from type I and type II NHBDs with the results of 250 from HBDs that were transplanted in our center between 2005 and 2012. Homogeneity between groups was tested and we evaluated the presence of delayed graft function (DGF) associated with pretransplant variables of the donor and recipient. ResultsBoth groups show homogeneity in pretransplant characteristics in terms of: age, HLA incompatibilities, and recipient hemodialysis time. Average follow-up time was 33 months (range 0–87) for NHBDs and 38 months (range 0–90) for HBDs. 5.5% of NHBDs showed primary non-function (PNF) vs. 4% of HBDs (p=0.42) and 80.9% of DGF vs. 46.8% of HBDs (p<0.001). At the end of the follow-up, there were no statistically significant differences in the survival of grafts (92.8% for NHBD vs. 93.6% for HBD, p=0.71) and recipients (99.1% NHBD vs. 98.6% HBD, p=0.28). ConclusionsAlthough the DGF percentage was greater for NHBDs, final creatinine as well as graft and recipient survival were similar for both groups. Therefore, in our experience, kidneys from NHBDs have similar results to those from HBDs and are an excellent source of organs for transplantation.

Prélèvement rénal sur donneur décédé par arrêt cardiaque (DDAC) : organisation dans un centre hospitalier non universitaire

In 2011 in France, all kidneys from patients with brain death and from living donors cannot meet the demand for renal transplants. Since 2006, sampling protocols kidneys from non-heart-beating donors (NHBD) are developed to increase the number of renal transplants. The objective was to describe the organization of a protocol NHBD in a non-university hospital. Patients with inclusion criteria of protocol NHBD of the Agency of Biomedicine were prospectively included between 1st July 2011 and 31 December 2012. The protocol data were comparable to national data. Vascular canulation was performed by urologists. The epidemiological, clinical and biological characteristics of patients included, the different times and deadlines of the protocol, and data of renal transplantation were collected and analyzed. Over the period of 18 months, 16 patients were included in the protocol NHBD, with a median age of 42 years, and 87.5% of males; 93.8% of patients made a cardiac arrest outside the hospital. The median duration of no-flow was 4.3 minutes (0; 23), the median time between the cardiac arrest and admission to hospital was 90 minutes (0; 116), the median time between the cardiac arrest and the start of the normothermic recirculation was 139 minutes (40; 150), and the median duration of normothermic recirculation was 212 minutes (186; 240). For urologists, the median duration of mobilization was 178 minutes and 97 minutes after 20 h. Twenty-four kidneys were collected (75%) and 22 kidneys were transplanted (91.7%). The median duration of cold ischemia was 9 h 12 (5 h 25; 18 h 02). No primary non-function of graft was observed. Delayed graft function was observed in 50% of cases and the median duration of dialysis was 2 days (0; 19). After 12 months of inclusion, our center accounted for 8% of the national census and 16% of transplanted kidneys NHBD. The involvement of rescue, coordination, anesthesiologists and urologists, and the concentration of jobs in our center have helped to minimize response times NHBD in the protocol for maximum quality of kidneys taken with transplant rates and results are very encouraging.

The effect of normothermic recirculation before cold preservation on post-transplant injury of ischemically damaged donor kidneys

Kidneys recovered from donation after cardiac death (DCD) are increasingly used to enlarge the deceased donor pool. Such renal grafts, especially those derived from uncontrolled DCD, have inevitably sustained profound warm ischemic injury, which compromises post-transplant function. Normothermic recirculation (NR) of the deceased donor's body before organ cooling could be an interesting approach to mitigate the detrimental effect of warm ischemia. To date, however, there is no evidence coming from preclinical studies to support the principle of NR in kidney transplantation. In this study, we subjected 48 Lewis rat kidneys to 15 or 30 min of warm ischemia, and subsequently 0, 1, or 2 h of NR. After 24 h cold storage, kidneys were transplanted into a recipient animal and 24 h later we measured the percentage of cortical necrosis, and determined gene expression of heme oxigenase-1, heat shock protein-70, transforming growth factor-β, kidney injury molecule-1, interleukin-6, hypoxia inducible factor-1α, monocyte chemoattractant protein-1, and α-smooth muscle actin in kidney tissue. We found that NR had no significant influence on any of these markers. Therefore, we conclude that this animal study by no means supports the presumed beneficial effect of NR on kidneys that have been severely damaged by warm ischemia.

Organ Procurement From Donors Deceased From Cardiac Death: A Single-Center Efficiency Assessment

Organ donation after cardiac death has been used for kidney and liver procurement in France since 2006. Until recently, most teams relied on in situ cold perfusion to prepare the donor before organ retrieval. Our team has used since 2007 normothermic abdominal recirculation. While this technique is presumed to be more difficult to implement, it also ensures a lower rate of primary nonfunction when compared to in situ cold perfusion. We present the efficiency results of our organ donation after cardiac death program. After 3 years, we have been able to establish a program in which we use normothermic abdominal recirculation in 97% of donors after cardiac death. The yearly efficiency of this program is comparable to the national efficiency of organ procurement from conventional deceased donors in France.

In-vivo normothermic recirculation: an update

The use of nonheart-beating donors (NHBD), as a source for liver grafts, is the only way to objectively increase the activity in liver transplantation. Through the use of more strict criteria, 1-year graft survival has increased from 50% in initial series to 84-100%. With respect to type II NHBD (failure of cardiopulmonary resuscitation) we believe that the use of normothermic recirculation provides the possibility to obtain good quality grafts for transplantation. Our recent experience shows a 66% and 73% graft and patient survival respectively. However, the incidence of biliary tract complications (ischemic type), as well as the relative low number of grafts procured that are finally transplanted, makes this methodology difficult to develop. The use of a 'normothermic machine perfusion' (once the liver is procured), added to the already described method, may actually increase the efficacy and safety of the whole procedure. Recent experience by our group as well as others have shown that the liver so perfused is able to recover from the warm ischemic lesion and at the same time the procedure allows the possibility to evaluate the quality of the potential graft. NHBD are the only source that may objectively increased the number of liver transplant. The use of normothermic recirculation has proved to be effective and well tolerated. The addition of the 'normothermic machine perfusion' to the whole procedure may significantly increase the number of transplants.

Antioxidant Patterns (Superoxide Dismutase, Glutathione Reductase, and Glutathione Peroxidase) in Kidneys From Non–Heart-Beating-Donors: Experimental Study

Introduction The evolution of renal antioxidant concentrations in the different phases of a non–heart-beating donor (NHBD) transplant after prolonged warm ischemia (40 and 90 minutes) and the effect of normothermic extracorporeal recirculation (37°C) for 30 minutes were evaluated on antioxidant tissue concentrations in the kidney. Methods Forty pairs of pigs, were divided into groups of 10 as follows: group 0, control donor with beating heart; group 1, 40 minutes of warm ischemia without recirculation by cardiopulmonary bypass pump (groups 2 and 3); group 2, 40 minutes of warm ischemia and recirculation for 30 minutes at 37°C; and group 3, 90 minutes of warm ischemia and recirculation for 30 minutes at 37°C. The concentrations of superoxide dismutase (SOD), glutathione peroxidase, and glutathione reductase were determined at the tissue level by biopsy at baseline the end of warm ischemia, the end of recirculation, at the end of cold ischemia, and 1 hour after reperfusion. Results SOD was consumed at the end of the cold ischemia phase ( P < .009) and increased during reperfusion ( P < .02). Glutathione reductase was consumed during the cold ischemia phase ( P < .04). In kidneys submitted to 40 minutes of warm ischemia, SOD was consumed during the cold ischemia phase ( P < .04) and increased with reperfusion ( P < .03). In kidneys undergoing 90 minutes of hot ischemia, SOD was consumed during cold ischemia ( P < .04) and glutathione reductase during extracorporeal recirculation ( P < .01). Conclusions Recirculation increased the tissue level of SOD at the end of the cold ischemia period.

The Effect of Normothermic Recirculation is Mediated by Ischemic Preconditioning in NHBD Liver Transplantation

We have evaluated the involvement of hepatic preconditioning mediators (adenosine, adenosine A1 and A2 receptors) during normothermic recirculation (NR) in a model of liver transplantation from non-heart-beating donor (NHBD) pigs. Application of NR after 20 min of warm ischemia (WI) reversed the lethal injury associated with transplantation of NHBD livers (achieving 5-day survival and diminishing glutathione S-transferase (GST), aspartate aminotransferase (AST) and hyaluronic acid (HA)). Adenosine administration prior to WI simulated the effect of NR. Measuring adenosine, we found that during NR, hepatic adenosine levels increased and xanthine levels decreased. Then when we blocked A2 receptors the effect of NR was abolished, whereas the blocking of A1 receptors further protected the liver. Furthermore, A2 blocking improved hepatic perfusion during NR whereas A1 blocking reduced it. The study suggests that NR has a preconditioning effect by maintaining adequate adenosine and xanthine levels. During NR, adenosine protects the liver through A2 activation and damages it through A1 activation although simultaneous stimulation of both receptors exerts a clear beneficial effect. The possible relation of NR mechanism with other preconditioning mediators such as cAMP and nitric oxide synthesis are discussed.

Hepatic preconditioning after prolonged warm ischemia by means of S-adenosyl-L-methionine administration in pig liver transplantation from non-heart-beating donors.

This study ascertained the effect of S-adenosyl-L-methionine (SAMe) administration on the ischemia-reperfusion injury associated with pig liver transplantation from non-heart-beating donors (NHBDs) after prolonged warm ischemia. Twenty-five animals underwent transplantation with an allograft from an NHBD. After donor cardiac arrest, cardiopulmonary bypass and normothermic recirculation (NR) were performed for 30 min. Ten animals were given SAMe during NR. Donors were cooled to 15 degrees C, and liver procurement was performed. SAMe reduced histologic liver damage 5 days after transplantation. The necrotic area affected 15.9%+/-14.5% of the liver biopsies in controls and 7.4%+/-9% in SAMe livers. Six of eight controls and only one of eight survivors in the SAMe group developed ischemic cholangitis. SAMe reduced apoptosis of hepatocytes 5 days after transplantation and apoptosis of sinusoidal endothelial cells at reperfusion and at 5 days. SAMe increased energy charge at the end of NR and favored the balance between adenosine and xanthine. It was also associated with higher portal blood flow (740+/-59.2 vs. 475.2+/-65.0 mL/min-1/m-2), hepatic hyaluronic acid extraction (132+/-72.2 vs. -205.8+/-64.6 microg/L), and lower levels of alpha-glutathione-S-transferase after reperfusion (2,601%+/-581% with respect to baseline vs. 6,488%+/-5,612%). SAMe administration during liver procurement from NHBDs prevents liver endothelial, parenchymal, and biliary tract damage. The protective role of SAMe may be partially mediated by the effect of adenosine during liver procurement.

Hepatic xanthine levels as viability predictor of livers procured from non-heart-beating donor pigs.

The aim of the present study was to evaluate hepatic content of adenine nucleotides and their degradation products in non-heart-beating donor (NHBD) pigs and its relationship with recipient survival. Thirty animals were transplanted with an allograft from NHBDs. After warm ischemia (WI) time (20, 30, or 40 min), cardiopulmonary bypass and normothermic recirculation (NR) were run for 30 min. Afterward, the animals were cooled to 15 degrees C and liver procurement was performed. Survival rate was 100% in the 20WI, 70% in the 30WI, and 50% in the 40WI. Livers from non-surviving animals had higher levels of xanthine after NR than livers from surviving animals. Logistic regression analysis revealed that xanthine at the end of NR was the only variable able to predict survival with a calculated sensitivity of 80% and a specificity of 60%. Prolongation of warm ischemic period leaded to a greater xanthine accumulation as well as increased plasma alpha-glutathione S-transferase levels at reperfusion. Xanthine at NR and alpha-glutathione S-transferase at reperfusion significantly correlated, indicating that donor xanthine contributes to some extent to the severity of the lesion by ischemia-reperfusion. It is suggested that xanthine content in the donor is able to predict survival after transplantation. Xanthine is significantly involved in the hepatic lesion elicited by warm ischemia and subsequent ischemia-reperfusion associated to liver transplantation from a NHBD.

Non Beating Heart Donors as a Possible Source for Liver Transplantation

Organ shortage for liver transplantation continues to be a major problem. Non heart beating donors (NHBD) are gaining increasing importance as a potential source of transplantable organs for clinical use, mainly in kidney transplantation. Up to now, the experience in liver transplantation with this type of donors has been limited and has only been considered in donors in whom cardiac arrest (CA) has occured at a known given time. This is due to the high risk of primary non-function and late complications related to intrahepatic biliary lesions when warm ischemia time (WIT) is not controlled. The method of retrieval of these organs should offer the possibility to stop liver injury, revert hisologic lesions appeared after WIT, and to assess the quality of the potential donor liver. Based on the experience of kidney transplantation, total body cooling achieved by extracorporal cardiopulmonary bypass seems to be the best method. Moreover it allows the inclusion of a time for tissue oxygenation at 37°C (Normothermic Recirculation, NR) prior to body cooling which has been shown to improve graft viability, and also allows a time to measure organ quality before transplantation. In our experience, we demonstrated that liver transplantation from NHBD is feasible; NR has beneficial effect on liver viability improving endothelial cell damage, hepatocyte energy charge and histological changes at 5 days. We also showed that time of cardiac arrest is determinant of graft viability; even if hepatocellular function is preserved after 40 minutes of CA using NR, irreversible intrahepatic biliary lesions are always present and burden longterm survival. Moreover, bypass pump and blood flows are directly related to WIT and the achievement of better pump flows may predict survival during NR. In animals with 40 minutes of CA, we also reported the possibility to manipulate the potential graft during NR with L-Arginine, Glycine and S-Adenosyl-Methyonine, which minimize endothelial and hepatocellular damage as well as lesions at 5 days. Further research needs to be done in order to confirm our experimental data.

L-arginine reduces liver and biliary tract damage after liver transplantation from non-heart-beating donor pigs.

To evaluate whether L-arginine reduces liver and biliary tract damage after transplantation from non heart-beating donor pigs. Twenty-five animals received an allograft from non-heart-beating donors. After 40 min of cardiac arrest, normothermic recirculation was run for 30 min. The animals were randomly treated with L-arginine (400 mg x kg(-1) during normothermic recirculation) or saline (control group). Then, the animals were cooled and their livers were transplanted after 6 hr of cold ischemia. The animals were killed on the 5th day, liver damage was assessed on wedged liver biopsies by a semiquantitative analysis and by morphometric analysis of the necrotic areas, and biliary tract damage by histological examination of the explanted liver. Seventeen animals survived the study period. The histological parameters assessed (sinusoidal congestion and dilatation, sinusoidal infiltration by polymorphonuclear cells and lymphocytes, endothelitis, dissociation of liver cell plates, and centrilobular necrosis) were significantly worse in the control group. The necrotic area affected 15.9 +/- 14.5% of the liver biopsies in the control group and 3.7 +/- 3.1% in the L-arginine group (P<0.05). Six of eight animal in the control group and only one of eight survivors in the L-arginine group developed ischemic cholangitis (P<0.01). L-Arginine administration was associated with higher portal blood flow (676.9 +/- 149.46 vs. 475.2 +/- 205.6 ml x min x m(-2); P<0.05), higher hepatic hialuronic acid extraction at normothermic recirculation (38.8 +/- 53.7% vs. -4.2 +/- 18.2%; P<0.05) and after reperfusion (28.6 +/- 55.5% vs. -10.9 +/- 15.5%; P<0.05) and lower levels of alpha-glutation-S-transferase at reperfusion (1325 +/- 1098% respect to baseline vs. 6488 +/- 5612%; P<0.02). L-Arginine administration during liver procurement from non heart beating donors prevents liver and biliary tract damage.

Normothermic recirculation reduces primary graft dysfunction of kidneys obtained from non-heart-beating donors

Normothermic recirculation reduces primary graft dysfunction of kidneys obtained from non-heart-beating donors

11 Normothermic recirculation in liver procurement from non heart beating donors: Is it a mechanism of preconditioning?

11 Normothermic recirculation in liver procurement from non heart beating donors: Is it a mechanism of preconditioning?

Evaluation of Ischemic Injury during Liver Procurement from Non-Heart-Beating Donors

The aim of this study was to assess liver viability after different periods of cardiac arrest and the predictive value of two markers of ischemia-reperfusion injury. Methods: A pig liver transplantation model of non-heart-beating donors was studied. Four donor groups were designed; three groups were submitted to different periods of cardiac arrest (20, 30 and 40 min), and the fourth group served as the control group (without cardiac arrest). In the non-heart-beating donor groups, normothermic recirculation was established 30 min prior to total body cooling. Aminotransferase, α-glutathione-S-transferase, and hyaluronic acid determinations as well as liver biopsies, were serially performed. Results: Although hepatocellular function could be preserved after 40 min of cardiac arrest, histological lesions at 5 days were considered irreversible due to the presence of a necrotic biliary tract. An overall significant relationship was found between the time period of cardiac arrest (20, 30 or 40 min) and the levels of hyaluronic acid (p = 0.004) or α-glutathione-S-transferase (p = 0.01) obtained during liver procurement and transplantation. Conclusions: The period of cardiac arrest is the determinant factor of liver viability after liver transplantation from non-heart-beating donors. As early markers of endothelial or hepatocellular damage, hyaluronic acid or α-glutathione-S-transferase levels may help to evaluate the ischemic injury of a potential donor.

NORMOTHERMIC RECIRCULATION IN LIVER PROCUREMENT FROM NON HEART BEATING DONORS: IS IT A MECHANISM OF PRECONDITIONING?

181 We have previously shown in an experimental model of liver transplantation (LTx) from non heart beating donors (NHBD), the beneficial effect of the use of normothermic recirculation (NR) during liver procurement. However, the mechanism through which NR is useful is unknown. It has also been stablished that brief periods of ischemia-reperfusion previous to long ischemia ameliorates the ischemia reperfusion injury and that this preconditioning effect is mediated by an increase in extracellular adenosine levels. AIM: The aim of this study was to investigate whether NR has a certain effect of conditioning and therefore its action would be mediated by an increase in extracellular adenosine (ADE) levels. MM: Fifteen out-bread weanling pigs (±30 Kg) were transplanted (LTx) from a NHBD with the following characteristics: Control group (CG, n=5): After a period of 20′ of cardiac arrest (KCl) liver was procured and transplantation performed after six hours of cold ischemia in an standard manner. Adenosine group (AG, n=5): as CG but adenosine was administered as a continous infusion (350μg/Kg/min) before cardiac arrest. Normothermic Recirculation Group (NRG, n=5): as CG but normothermic recirculation (NR) by using cardiopulmonary bypass (CPB) was performed during 30 minutes after cardiac arrest. Blood samples to determine hepatocellular (AST, α-GST), and endothelial damage (hyaluronic acid, HA) were taken (in the donor) at the beginning (BL), after cardiac arrest (CA), after 30′ of NR; (in the recipient): at the end of total ischemia (TI) one hour after reperfusion (RP); and five (5D) days after Ltx. Values were expressed as percentage of baseline. HA clearance (marker of endothelial cell function) was calculated as follows: (systemic HA- suprahepatic vein HA)*100/ systemic HA. Liver biopsies were obtained at the same time as blood to determine tissue adenine nucleotides and adenosine levels by High Performance Liquid Chromatography (HPLC). RESULTS: Survivals were 1/5(CG), 4/5 (AG) and 5/5 (NRG). At the end of organ procurement ADE levels were significantly higher in AG and NRG than in CG (126.22±31.7; 193.3±154.6 vs. 48.4±16, p<0.05). Throughout the study ASAT increase was higher in CG than in AG and NRG, reaching statistical significance at 2D post LTx between CG and AG (6732±3365 vs. 1390±889, p=0.03). α-GST increase was also higher throughout the study in CG; being the values in AG and NRG similar in all phases studied. HA clearance at RP was negative in CG, slightly negative or near to zero in NRG, and positive values were only obtained in AG animals, indicating a better endothelial cells function in this group. CONCLUSION: Preliminary results suggests that adenosine administration seems to obtain the same beneficial effect as normothermic recirculation during liver procurement in terms of survival, parenchymal and endothelial damage. Normothermic recirculation produces adenosine levels at the end of organ procurement similar to those obtained by adenosine administration. Therefore, donor conditioning may be the mechanism through which normothermic recirculation works.