Reperfusion In Transplantation Research Articles

REmote preconditioning for Protection Against Ischaemia–Reperfusion in renal transplantation (REPAIR): a multicentre, multinational, double-blind, factorial designed randomised controlled trial

BackgroundLong-term kidney allograft survival has remained unchanged in recent years despite immunosuppressive and surgical advances. Ischaemia–reperfusion (IR) injury sustained at transplantation contributes to kidney damage that limits allograft lifespan. Interventions to reduce IR injury may prolong graft life, delaying the need for a return to dialysis. Remote ischaemic preconditioning (RIPC), in which brief episodes of non-lethal ischaemia applied to the limb activate a systemic protective reflex against subsequent damaging IR injury, has been reported to cause cardiac, renal and neurological protection in small-scale trials.ObjectivesThe REmote preconditioning for Protection Against Ischaemia–Reperfusion in renal transplantation (REPAIR) trial investigated whether RIPC improves kidney function and other outcomes following living-donor renal transplantation.DesignMulticentre, multinational, double-blind, 2 × 2 factorial designed randomised controlled trial.SettingThirteen tertiary care hospitals in the UK, the Netherlands, Belgium and France.ParticipantsThe REPAIR trial recruited 406 live donor–recipient pairs aged ≥ 18 years. Patients on adenosine triphosphate (ATP)-sensitive potassium channel opening or blocking drugs, on ciclosporin, with a known iodine sensitivity or with ABO incompatibility or those requiring human leucocyte antigen (HLA) antibody removal therapy were excluded.InterventionsEach pair was randomised using a factorial design to one of four groups: sham RIPC, early RIPC (immediately before surgery), late RIPC (24 hours before surgery) and dual RIPC (early and late RIPC). The donor and recipient received the same intervention (active RIPC or sham RIPC) at the two time points.Main outcome measuresThe primary outcome was glomerular filtration rate (GFR) 12 months after transplantation measured by iohexol clearance. Important secondary outcomes were estimated GFR (eGFR) (using routine clinical assessment), safety, inflammatory cytokine profile and biological mechanisms.ResultsIn total, 406 donor–recipient pairs were randomised: 99 to sham RIPC, 102 to early RIPC, 103 to late RIPC and 102 to dual RIPC. Early RIPC resulted in a small but clinically important increase in iohexol GFR (ml/minute/1.73 m2) at 12 months, although the evidence is weak [58.3 vs. 55.9; adjusted difference 3.08, 95% confidence interval (CI) –0.89 to 7.04;p = 0.13], likely because of the higher than expected variability in the iohexol measurements. There was stronger evidence for a treatment effect when eGFR was used and missing values imputed (adjusted difference 3.41, 95% CI –0.21 to 7.04;p = 0.065) and when eGFR was used to assess kidney function (adjusted difference 4.98, 95% CI 1.13 to 8.29;p = 0.011). Late RIPC had no effect on renal outcomes, there was no benefit of combining early and late RIPC and RIPC had no effect on the inflammatory response to surgery. RIPC was safe and well tolerated by recipients and donors.ConclusionsRIPC is a safe intervention in living-donor transplantation. The evidence for an effect of RIPC on GFR (primary outcome) was weak, but other measures of GFR (in our secondary analysis) provided persuasive evidence of a clinically meaningful improvement in kidney function after transplantation. Future work should investigate the role of RIPC in deceased-donor kidney transplantation.Trial registrationCurrent Controlled Trials ISRCTN30083294.FundingThis project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council and National Institute for Health Research partnership.

Results of the REPAIR Randomised Controlled Trial - Renal Protection Against Ischaemia Reperfusion in Transplantation.

Results of the REPAIR Randomised Controlled Trial - Renal Protection Against Ischaemia Reperfusion in Transplantation.

Predictive Factors of Vasopressor Weaning After Reperfusion in Liver Transplantation.

Predictive Factors of Vasopressor Weaning After Reperfusion in Liver Transplantation.

Predictive factors associated with the development of arrhythmia after reperfusion in liver transplantation

Asan Medical Center, University of Ulsan College of Medicine, Dept of Anaesthesiology & Pain Medicine, Seoul, Korea, Republic of

Epsilon‐aminocaproic Acid Improves Postrecirculation Hemodynamics by Reducing Intraliver Activated Protein C Consumption in Orthotopic Liver Transplantation

Activated protein C (APC) is related to regulating the inflammatory response and hemodynamic stability upon reperfusion in cardiac operations and orthotopic liver transplantation (OLT). Epsilon-aminocaproic acid (EACA) is frequently used to treat fibrinolysis during OLT. It also has inhibitory effects related to the inflammatory response. However, it remains to be determined whether EACA can attenuate intraliver APC consumption and improve hemodynamic stability after reperfusion during OLT. Fifty-nine recipients were randomized to receive either EACA (150 mg kg(-1) given intravenously prior to incision, followed by 15 mg kg(-1) h(-1) infusion until 2 h after the graft reperfusion) or the same volume of saline. Blood samples to assess plasma APC and protein C were obtained immediately before and after reperfusion from the inferior caval effluent or the portal veins for calculation of transliver differences (Δ). Hemodynamics and vasoactive medication use during the reperfusion period were observed in both groups. No transhepatic changes in protein C were found in either group. Immediately after reperfusion, a marked intraliver consumption of APC was noted in all recipients (P < 0.001), and intraliver consumption of APC in the control group was greater than that in the EACA-treated group (P < 0.05). Fewer requirements for vasoactive medication use after reperfusion and better initial graft function were noted in the EACA-treated group (P < 0.05). EACA can attenuate intraliver APC consumption and improve hemodynamic stability after reperfusion and initial graft function during OLT.

High prevalence of vitamin A deficiency and vitamin D deficiency in patients evaluated for liver transplantation

Deficiencies in vitamins A, D, and E have been linked to night blindness, bone health, and post–liver transplant reperfusion injury. The aim of this study was to determine the prevalence and predictive factors of fat-soluble vitamin deficiencies in liver transplant candidates. We reviewed the medical records of liver transplant candidates at our center from January 2008 to September 2011. The etiology of cirrhosis, Model for End-Stage Liver Disease score, Child-Pugh class, body mass index (BMI), and vitamin A, vitamin E, and vitamin 25-OH-D levels were recorded. Patients were excluded for incomplete laboratory data, short gut syndrome, celiac disease, pancreatic insufficiency, or prior liver transplantation. Sixty-three patients were included. The most common etiologies of liver disease were alcohol (n = 23), hepatitis C virus (n = 19), and nonalcoholic steatohepatitis (n = 5). Vitamin A and D deficiencies were noted in 69.8% and 81.0%, respectively. Only 3.2% of the patients were vitamin E–deficient. There were no documented cases of night blindness. Twenty-five of the 55 patients with bone density measurements had osteopenia, and 10 had osteoporosis. Four patients had vertebral fractures. There was 1 case of posttransplant reperfusion injury in a patient with vitamin E deficiency. In a multivariate analysis, there were no statistically significant predictors for vitamin D deficiency. The Child-Pugh class [odds ratio (OR) = 6.84, 95% confidence interval (CI) = 1.52-30.86, P = 0.01], elevated total bilirubin level (OR = 44.23, 95% CI = 5.02-389.41, P < 0.001), and elevated BMI (OR = 1.17, 95% CI = 1.00-1.36, P = 0.045) were found to be predictors of vitamin A deficiency. In conclusion, the majority of liver disease patients evaluated for liver transplantation at our center had vitamin A and D deficiencies. The presence or absence of cholestatic liver disease did not predict deficiencies, whereas Child-Pugh class, bilirubin level, and elevated BMI predicted vitamin A deficiency. Liver Transpl 19:627–633, 2013. © 2013 AASLD.

Timing of Hepatic Artery Reperfusion and Biliary Strictures in Liver Transplantation

During orthotopic liver transplantation (OLT), biliary tract perfusion occurs with hepatic artery reperfusion (HARP), commonly performed after the portal vein reperfusion (PVRP). We examined whether the average time interval between PVRP and HARP impacted on postoperative biliary strictures occurrence. Patients undergoing OLT from 2007 to 2009 were included if they were ≥18 years old, had survived 3 months postoperatively, and had data for PVRP and HARP. Patients receiving allografts from DCD donors were excluded. Patients were followed for 6 months post-OLT. Seventy-five patients met the study inclusion criteria. Of these, 10 patients had a biliary stricture. There was no statistical difference between those with and without biliary stricture in age, gender, etiology, MELD score, graft survival, and time interval between PVRP and HARP. Ninety percent of patients with biliary stricture had a PVRP-HARP time interval >30 minutes, as opposed to 77% of patients without biliary stricture. However, this was not statistically significant. The cold ischemia time was significantly different between the two groups. Time interval for HARP after PVRP did not appear to affect the development of biliary strictures. However, 30 minutes may be suggested as a critical time after which there is an increase in biliary stricture occurrence.

Podocyte Foot Process Effacement in Postreperfusion Allograft Biopsies Correlates With Early Recurrence of Proteinuria in Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a relatively prevalent glomerular disorder that often progresses to end-stage renal disease. Thirty to 80% of kidney transplant (KT) recipients with FSGS will experience recurrence characterized by proteinuria and podocyte damage. We hypothesized that the degree of podocyte foot process (FP) effacement in postreperfusion transplant biopsies can be used to predict the development of clinical recurrence of FSGS. Nineteen pairs of pre- and postreperfusion biopsy specimens were studied. We evaluated the degree of FP effacement in postreperfusion KT biopsies by counting the number of widened FP per capillary loop. Early recurrence of FSGS was defined as development of nephrotic range proteinuria between days 3 and 30 posttransplant. Early recurrence occurred in 7 of 19 grafts (36.8%) at a mean of 4.29±1.89 days. The mean score of FP effacement in postreperfusion allograft biopsies was 0.72±0.31 and 1.35±0.63 in the nonrecurrent and recurrent group, respectively (P=0.039). There was an association between FP effacement and proteinuria (P = 0.04). The FP effacement score predicts early recurrence with a sensitivity of 71.4% and specificity of 91.7%. FP effacement can be observed within minutes after reperfusion in renal transplantation of recipients with FSGS that will ultimately develop recurrent FSGS. This suggests a key role for the podocyte injury in the pathogenesis of recurrent FSGS and further supports the presence of circulating factors causing FP effacement. The FP effacement score in the postreperfusion KT biopsy may become a useful predictive test if validated in larger studies.

The effects of magnesium pretreatment on reperfusion injury during living donor liver transplantation

BackgroundIschemia reperfusion (IR) injury is a complex phenomenon that leads to organ dysfunction and causes primary liver failure following liver transplantation. We investigated whether an intravenous administration of magnesium before reperfusion can prevent or reduce IR injury.MethodsFifty-nine living donor liver transplant recipients were randomly assigned to an MG group (n = 31) or an NS group (n = 28). Each group was also divided in two groups based on the preoperative magnesium levels (normal: ≥ 0.70 mmol/L, low: < 0.70 mmol/L). The MG groups received 25 mg/kg of MgSO4 mixed in 100 ml normal saline intravenously before reperfusion and the NS groups received an equal volume of normal saline. The levels of lactate, pH, arterial oxygen tension, and base excess were measured to assess reperfusion injury at five specific times, which were 10 min after the beginning of anhepatic phase, and 10, 30, 60 and 120 min after reperfusion. To evaluate postoperative organ function, the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin and creatinine levels were measured at preoperative day 1, postoperative day 1 and 5.ResultsThe blood lactate levels were significantly lower at 10, 30, 60 and 120 min after reperfusion in the MG groups compared to the NS groups. In addition, significantly higher blood lactate levels were observed in the NS group with preoperative hypomagnesemia than in MG groups.ConclusionsMagnesium administration before reperfusion of liver transplantation significantly reduces blood lactate levels. These findings suggest that magnesium treatment may have protective effects on IR injury during living donor liver transplantation.

Hypotension after Reperfusion in Liver Transplantation: Histidine-Tryptophan-Ketoglutarate versus University of Wisconsin Solution

The greatest hemodynamic instability during orthotopic liver transplantation occurs at graft reperfusion. Many factors have been implicated. To compare hemodynamic changes after reperfusion in grafted livers preserved with histidine-tryptophan-ketoglutarate (HTK) solution versus grafted livers preserved with University of Wisconsin (UW) solution. In this prospective study, we randomly divided 89 patients who underwent deceased donor liver transplantation into 2 groups: the UW group and the HTK group. The HTK group was further divided into 2 subgroups: flushed and not flushed before reperfusion. The patients were monitored with hemodynamic and metabolic parameters at 3 times: after the skin incision, 5 minutes before reperfusion, and 5 minutes after reperfusion. Hemodynamic parameters in the UW group had not changed significantly at 5 minutes before reperfusion or 5 minutes after reperfusion (P = .45), and the incidence of hypotension after reperfusion in the UW group was 20%. In both HTK groups, the mean arterial pressure 5 minutes after reperfusion was significantly lower than at 5 minutes before reperfusion (P = .002); the incidence of hypotension after reperfusion in the nonflushed HTK group was 83.3% and in the flushed HTK group, 65.5%. The incidence of hypotension after reperfusion is greater if HTK solution rather than UW solution is used. Flushing of grafted livers preserved with HTK solution might eliminate some vasoactive substances found in HTK solution.

Hypotension after reperfusion in liver transplantation: histidine-tryptophan-ketoglutarate versus University of Wisconsin solution

The greatest hemodynamic instability during orthotopic liver transplantation occurs at graft reperfusion. Many factors have been implicated. To compare hemodynamic changes after reperfusion in grafted livers preserved with histidine-tryptophan-ketoglutarate (HTK) solution versus grafted livers preserved with University of Wisconsin (UW) solution. In this prospective study, we randomly divided 89 patients who underwent deceased donor liver transplantation into 2 groups: the UW group and the HTK group. The HTK group was further divided into 2 subgroups: flushed and not flushed before reperfusion. The patients were monitored with hemodynamic and metabolic parameters at 3 times: after the skin incision, 5 minutes before reperfusion, and 5 minutes after reperfusion. Hemodynamic parameters in the UW group had not changed significantly at 5 minutes before reperfusion or 5 minutes after reperfusion (P = .45), and the incidence of hypotension after reperfusion in the UW group was 20%. In both HTK groups, the mean arterial pressure 5 minutes after reperfusion was significantly lower than at 5 minutes before reperfusion (P = .002); the incidence of hypotension after reperfusion in the nonflushed HTK group was 83.3% and in the flushed HTK group, 65.5%. The incidence of hypotension after reperfusion is greater if HTK solution rather than UW solution is used. Flushing of grafted livers preserved with HTK solution might eliminate some vasoactive substances found in HTK solution.

Inducible NO synthase expression in endomyocardial biopsies after heart transplantation in relation to the postoperative course

Ischemia and reperfusion during heart transplantation cause damage to cardiomyocytes and endothelial cells and may initiate later acute rejection. Free oxygen radicals generated by iNOS are widely accepted to be responsible for ischemic injury. Increased iNOS expression on cardiac tissue may represent a more intensive tissue injury during ischemia and reperfusion in heart transplantation. The aim of this study was, therefore, to test the hypothesis that increased iNOS expression in early postoperative endomyocardial biopsies correlates with rejection or infection episodes in the later postoperative course. Right ventricular endomyocardial biopsies were obtained from heart transplantation recipients at transplantation and during the first 2 weeks postoperatively. The recipients were divided into three groups depending on the postoperative course during the first year after transplantation: patients in group 1 had an uncomplicated postoperative course, patients in group 2 developed significant signs of postoperative infection, while patients in group 3 presented with acute rejection (< or =grade 2R ISHLT). The expression was analyzed in a semi-quantitative score. iNOS expression was found in cardiomyocytes, endothelial cells, infiltrating cells, and vascular smooth muscle cells. At the time of heart transplantation, the expression was significantly increased in the rejection group compared to the other groups. This increase was even more pronounced in week 2. The present study shows that an increased iNOS expression at the time of heart transplantation could precede an acute rejection in the later postoperative course. Thus, measurements of iNOS expression may be of predictive value for an increased rejection risk and therefore offer the possibility of earlier therapeutic intervention.

Tissue thiamine deficiency as potential cause of delayed graft function after kidney transplantation: Thiamine supplementation of kidney donors may improve transplantation outcome

Delayed graft function is an important medical problem after renal transplantation. It occurs in approximately 30% of cases, and is not only associated with more prolonged and complicated hospitalisation, but also with earlier graft loss on the long-term. Delayed graft function is the consequence of acute tubular necrosis caused by ischaemia-reperfusion injury, with insufficiently opposed toxic effects of reactive oxygen species and insufficient ATP regeneration. An optimal tissue thiamine status is pivotal for scavenging of reactive oxygen species and regeneration of ATP. There are several reasons to suppose that tissue thiamine availability is suboptimal in donor kidneys prior to reperfusion in transplantation. These reasons include a high prevalence of untreated thiamine deficiency at admission of donors to intensive care units, quick exhaustion of body thiamine stores during periods of non-feeding or inappropriate feeding during hospital stays of donors, and loss of the water-soluble vitamin into water-based organ preservation solutions. We therefore hypothesize that a suboptimal tissue thiamine status is a cause of delayed graft function after renal transplantation, and that it can be prevented with thiamine supplementation.

Cytokine Profile After Lung Transplantation: Correlation With Allograft Injury

Post-lung transplant reperfusion edema (PLTRE) and its more severe form, primary graft failure (PGF), occur in 10% to 60% of lung transplant recipients. We hypothesized that PLTRE and PGF would be associated with an elevated proinflammatory cascade and that the allograft would be the source of cytokine appearance in the circulation. Pulmonary arterial and systemic arterial samples were obtained at baseline and at 4, 8, and 24 hours after reperfusion. Post-lung transplant reperfusion-edema and PGF were defined as PaO2/FiO2 less than 300 with a mild or moderate infiltrate, or less than 200 with a severe infiltrate and ventilator dependence after 72 hours, respectively. Tumor necrosis factor alpha (TNFalpha), interleukin (IL)-6, IL-8, and IL-10 concentrations were determined by immunoassay. Fifteen single and 6 bilateral lung recipients were studied. Six (29%) had PLTRE and 4 (19%) had PGF; these patients had an overall elevation in plasma IL-6, IL-8, and IL-10 concentrations (all p < 0.05). Subgroup analysis revealed a significantly greater elevation in IL-6, IL-8, and IL-10 levels in PGF patients (all p < 0.01) versus PLTRE. In the PGF group, TNFalpha and IL-10 concentrations were significantly greater in the systemic versus the pulmonary arterial samples (p < 0.05). Patients with PLTRE and PGF exhibited graded increases in IL-6, IL-8, and IL-10 concentrations. The PGF patients had higher TNFalpha and IL-10 systemic arterial concentrations overall, consistent with the allograft being a source of this cytokine production.

S-nitroso Human Serum Albumin Attenuates Ischemia/Reperfusion Injury After Cardioplegic Arrest in Isolated Rabbit Hearts

Depletion of nitric oxide (NO) is associated with ischemia/reperfusion injury. The novel NO donor, S-nitroso human serum albumin (S-NO-HSA), could bridge NO depletion during reperfusion in cardiac transplantation and minimize ischemia/reperfusion injury. In an isolated erythrocyte-perfused working heart model, rabbit hearts were randomly assigned after assessment of hemodynamic baseline values to receive S-NO-HSA (0.2 micromol/100 ml, n = 8), L-arginine (10 mmol/100 ml, n = 8) or albumin (control) (0.2 micromol/100 ml, n = 8). After 20 minutes of infusion, the hearts were arrested and stored in Celsior (4 degrees C) enriched with respective drugs for 6 hours, followed by 75 minutes of reperfusion. Hemodynamic values were assessed and biopsy specimens were taken to determine calcium-ionophore stimulated release of NO and superoxide. During early reperfusion, recovery of cardiac output (75% +/- 6% vs 49% +/- 5%, p < 0.05) and coronary flow (99% +/- 8% vs 70% +/- 5%, p < 0.05) were higher, and myocardial oxygen consumption was reduced in the S-NO-HSA Group compared with Control (4.08 +/- 0.46 ml/min/0.1 kg vs 6.78 +/- 0.38 ml/min/0.1 kg, p < 0.01). At the end of the experiment cardiac output (53% +/- 5% vs 27% +/- 5%, p < 0.01) was higher and left atrial pressure (115% +/- 9% vs 150% +/- 8%, p < 0.05) was lower in the S-NO-HSA Group compared with Control. NO release was increased (1,040 +/- 50 nmol/liter and 1,070 +/- 60 nmol/liter vs 860 +/- 10 nmol/liter, p < 0.01) and superoxide release diminished (31 +/- 5 nmol/liter and 38 +/- 5 nmol/liter vs 64 +/- 5 nmol/liter, p < .01) in the S-NO-HSA and L-arginine Groups compared with Control. S-NO-HSA improved hemodynamic functions after prolonged hypothermic cardiac arrest by supplementing NO and thereby decreasing ischemia/reperfusion injury.

Benefit of Kupffer cell modulation with glycine versus Kupffer cell depletion after liver transplantation in the rat: effects on postischemic reperfusion injury, apoptotic cell death graft regeneration and survival*

Inhibition or destruction of Kupffer cells (KC) may protect against ischemia-reperfusion (IR) induced primary graft nonfunction (PNF) in liver transplantation. Besides KC activation, PNF is characterized by microvascular perfusion failure, intrahepatic leukocyte accumulation, cell death and hepatocellular dysfunction. KCs can be inactivated by different agents including gadolinium chloride (GdCl3), methyl palmitate (MP) and glycine. The effects of three KC inactivators on IR-injury after rat liver transplantation were compared in the present study. Lewis liver donors were treated with GdCl3, MP, glycine or saline (control). Liver grafts were transplanted following 24 h storage (UW solution). KC populations and IR damage were assessed by histologic analysis, quantitative real-time polymerase chain reaction (RT-PCR) and intravital microscopy. The number of hepatic ED-1 positive macrophages was diminished after GdCl3 (114.8+/-4.4/mm2 liver tissue) and MP treatment (176.0+/-5.0), versus the glycine (263.9+/-5.5) and control (272.1+/-5.6) groups. All three treatment modalities downregulated phagocytic activity for latex particles, paralleled by reduced microvascular injury (acinar perfusion index, GdCl3: 0.75+/-0.03; MP: 0.83+/-.03; glycine: 0.84+/-0.03; 0.63+/-0.03). Quantitative RT-PCR revealed elevated myeloperoxidase mRNA after glycine versus GdCl3 and MP pretreatment (3.2- and 3.4-fold, P=0.011, respectively), without difference to controls (2.9-fold of glycine). TNFalpha-mRNA was reduced after glycine- (5.2-fold), GdCl3- (19.7-fold), MP-treatment (39.5-fold) compared with controls. However, profound prevention of intrahepatic cell death and liver graft failure was solely achieved with glycine preconditioning. Different than GdCl3 and MP, glycine modulates rather than destroys KCs. Glycine appears to preserve cell viability and to TNFalpha/leukocyte dependent organ regeneration capacity, which is related to increase graft survival following liver transplantation.

The Effect of Low Dose Aprotinin on Postreperfusion Fibrinolysis in Liver Transplantation

Background: The patients with end-staged liver failure are subjected to various and complex coagulopathies during liver transplantation. Particularly, fibrinolysis can occur preoperatively and is more prominent and aggravated right after reperfusion to the donated liver. It becomes the main cause of bleeding intraoperatively and postoperatively. We examined the effect of low dose aprotinin on the fibrinolysis and the transfusion amount of the packed red cell during operation. Methods: We divided the patients into an experimental group, administrating aprotinin (n = 20) and a control group, administrating same volume of normal saline (n = 28). Heparinase-guided thromboelastograph (h-TEG) of preanhepatic 60 minutes was done as basic value. Then we administrated 1 million KIU aprotinin for 20 minutes and infused 0.25 million KIU /hr aprotinin for 3 hours of preanhepatic period in the experimental group. Just after the reperfusion to donated liver, another h-TEG of postanhepatic 10 minutes was done. We obtained CL 60 (clot lysis 60) and MA (maximum amplitude) among the TEG parameters and counted the total number of packed red cell transfused before and after the reperfusion period. Results: The results showed that the experimental group had significantly higher value of CL 60 and MA in the h-TEG of postanhepatic 10 minutes and lower amount of packed red cell transfusion during the period after the reperfusion. Conclusions: The administration of low dose aprotinin during preanhepatic period reduced the activation of fibrinolysis and the total packed red blood cell transfusion after the reperfusion in liver transplantation.

Factors affecting metabolic and electrolyte changes after reperfusion in liver transplantation

Background The metabolic and electrolyte changes were evaluated after various durations of cold and warm ischemia times to correlate ASA status with hemodynamic changes that may affect the severity of the reperfusion syndrome. Patients and methods Sixty-one patients who underwent liver transplantation (OLT) were monitored by arterial pH, PaO 2, PaCO 2, HCO 3, BE, K +, Ca 2+, Na +, GL, and serial Ht at three specific times: after the skin incision (baseline), 10 minutes before reperfusion (T 2), and 10 minutes after reperfusion (T 3). Changes in metabolic parameters were correlated with ASA status, hemodynamic changes, time of OLT, as well as cold and warm ischemia times. Results The pH in ASA IV patients was significantly lower at T 1 and T 3, and PCO 2 higher in ASA V at T 1. A significant correlation was observed between pH, PaCO 2, HCO 3 −, BE, Na +, Ca 2+, and glucose with the phase of the procedure. The pH and HCO 3 − decreased significantly from T 1 and T 2, increasing during T 3. Ca 2+ fell from T 1 to T 2 increasing in T 3. Mean glucose and sodium levels increase from T 1 to T 3. Mean BE dropped from T 1 to T 2 and increased at T 3 without a significant correlation between the metabolic parameters in any phase of the study and the cold or warm ischemia times. Patients with a high ASA status showed an increased risk for cardiovascular collapse after reperfusion. Conclusions Patients with advanced ASA status are more prone to metabolic and acid-base disturbances during reperfusion, without any relation to the cold or warm ischemia times. High ASA status shows an increased risk for cardiovascular collapse after reperfusion.

Response: Adenovirus-Mediated Gene Transfer to the Rat Heart Graft

Ogata et al. (1) demonstrate interesting findings regarding the expression of the luciferase gene after adenoviral transfection in rat hearts. The fact that gene expression was detected supports our technique of retrograde aortic injection at the time of donor heart procurement as a method of selective gene manipulation in the perioperative period (2). It is true that adenoviral vectors can cause an inflammatory response that could confound the results of any study using this vector. This is the reason that we selected null adenovirus controls for our experiments. Because of the use of these controls, we believe that the effects we demonstrated on reperfusion injury and graft coronary artery disease were due to the single altered variable, that is, the upregulation of bcl-2. Regarding our use of the syngeneic-allogeneic retransplantation technique, the main purpose of this method is to allow for maximal translation of the bcl-2 gene product at the time of allogeneic transplant reperfusion. As Kita et al. (3) demonstrated, this gene expression occurs at detectable levels over a course of approximately 7 days, and according to our unpublished preliminary data, this expression was optimal at 4 days after the syngeneic transplant. Another way of conceptualizing this double-transplant technique is that the syngeneic recipient essentially acts as a stable environment for bcl-2 gene upregulation, or a relatively inert means by which to house the genetically altered graft until the appropriate time for retransplantation. We did not observe any episodes of cardiac arrest attributed to adenoviral therapy. Regarding the concern that our model is not immediately clinically applicable, we agree. Our purpose was to demonstrate the potential importance of bcl-2 in the short and long-term function of heart allografts, and our model happened to incorporate the use of adenovirus to prove our hypothesis. The issues involved with the use of adenovirus in humans are many, and we do not expect to see adenoviral vectors utilized in the human transplant setting in the near future. However, a variety of pharmacological agents are utilized during the organ procurement process and, considering our data, it would be of interest to see how these agents affect the expression of bcl-2. Douglas N. Miniati Robert C. Robbins Department of Cardiothoracic Surgery Stanford University Stanford, CA

Polyclonal anti-thymocyte globulins influence apoptosis in reperfused tissues after ischaemia in a non-human primate model

Abstract Reperfusion triggers the expression of inflammatory cytokines and adhesion molecules that increase the rate of apoptosis in the reperfused tissues after ischaemia, thus worsening the outcome of the grafts. Polyclonal anti-thymocyte globulins (pATGs) are able to reduce the number of lymphocytes as well as block adhesion molecules and induce apoptosis in T-lymphocytes through Fas-ligand. The aims of this study were to investigate the influence of pATGs on the prevention of apoptosis of reperfused tissues after ischaemia and to monitor their capability to enhance lymphocyte apoptosis thus decreasing the deleterious effects of ischaemia/reperfusion injury (IRI). Extremities of cynomolgus monkeys (n= 8) were flushed via either the femoral or the brachial artery. After 60 min of ischaemia the limbs were reperfused with human blood. ATG was added to the blood in a therapeutic dose 20 min prior to reperfusion of the extremities. Surgically available limbs (n= 20) were assigned to the following groups: ATG group (n= 10) and control group (without ATG; n= 10). DNA fragmentation analysis was performed in situ to detect apoptosis at the single-cell level. Our study shows an increased rate of muscle and connective tissue apoptosis in the control group compared with the ATG-treated group. Cells found in the vascular areas present different rates of apoptosis, with enhanced cellular death of endothelium and connective perivascular areas being observed in the control group. The group treated with ATG shows an increased rate of white blood cell (WBC) apoptosis in vascular and perivascular areas. Previous studies have shown that pATGs are able to induce apoptosis as well as complement-mediated cell death in peripheral T-lymphocytes in vitro. Our results confirm that pATGs not only increase the rate of apoptosis of WBCs in vivo but also have a protective effect on the reperfused tissue. This may alleviate the damage after reperfusion of solid-organ transplantation.