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Background Normothermic machine perfusion (NMP) bears the potential for significant prolongation of liver preservation before transplantation. Although safety and feasibility have been recently published, no data are available describing the significant challenges of establishing NMP programs outside clinical studies. We herein present our experience and propose a multidisciplinary approach for liver NMP in the clinical routine. Methods In February 2018, liver NMP was introduced for routine use in marginal organs, logistic challenges, and complex recipients at our institution. In a multidisciplinary effort among transplant coordinators, perfusionists, transplant surgeons, anesthesia, nurses, blood bank as well as laboratory staff, a clinical routine was established and 34 NMP cases were performed without critical incidents or organ loss. Results Nine livers were discarded due to poor organ quality and function observed during NMP. Twenty-five livers were successfully transplanted after preservation of up to 38 h. The extended criteria donors rate was 100% and 92% in discarded and transplanted livers, respectively. Nighttime procedures and parallel transplantations were eventually omitted. Graft and patient survival was 88% at 20 mo. No cholangiopathy was observed despite the use of extended criteria donor organs in 92% of cases. Conclusions NMP in a multidisciplinary approach enables a safe prolongation of liver preservation and overnight organ care. A first field test of NMP indicates safety and benefit of this approach.

Normothermic machine perfusion (NMP) has become a clinically established tool to preserve livers in a near-physiological environment. However, little is known about the predictive value of perfusate parameters toward the outcomes after transplantation.Fifty-five consecutive NMP livers between 2018 and 2019 were included. All of the livers were perfused on the OrganOx metra device according to an institutional protocol. Transplant and perfusion data were collected prospectively.Forty-five livers were transplanted after NMP. Five livers stem from donors after circulatory death and 31 (68.9%) from extended criteria donors. Mean (SD) cold ischemia time was 6.4 (2.3) h; mean (SD) total preservation time was 21.4 (7.1) h. Early allograft dysfunction (EAD) occurred in 13 of 45 (28.9%) patients. Perfusate aspartate aminotransferase (P = 0.008), alanine aminotransferase (P = 0.006), lactate dehydrogenase (P = 0.007) and their development over time, alkaline phosphatase (P = 0.013), and sodium (P = 0.016) correlated with EAD. Number of perfusate platelets correlated with cold ischemia time duration and were indicative for the occurrence of EAD. Moreover, von Willebrand Factor antigen was significantly higher in perfusates of EAD livers (P 0.001), and Δ von Willebrand factor antigen correlated with EAD. Although perfusate lactate and glucose had no predictive value, EAD was more likely to occur in livers with lower perfusate pH (P = 0.008). ΔPerfusate alkaline phosphatase, Δperfusate aspartate aminotransferase, Δperfusate alanine aminotransferase, and Δperfusate lactate dehydrogenase correlated closely with model for early allograft function but not liver graft assessment following transplantation risk score. Bile parameters correlated with extended criteria donor and donor risk index.Biomarker assessment during NMP may help to predict EAD after liver transplantation. The increase of transaminases and lactate dehydrogenase over time as well as platelets and vWF antigen are important factors indicative for EAD.

Introduction: Early graft dysfunction (EAD) complicates liver transplantation (LT). The aim of this analysis was to discriminate between the weight of each variable as for its predictive value toward patient and graft survival.Methods: We reviewed all LT performed at the Medical University of Innsbruck between 2007 and 2018. EAD was recorded when one of the following criteria was present: (i) aspartate aminotransferase (AST) levels >2,000 IU/L within the first 7 days, (ii) bilirubin levels ≥10mg/dL or (iii) international normalized ratio (INR) ≥1.6 on postoperative day 7.Results: Of 616 LT, 30.7% developed EAD. Patient survival did not differ significantly (P = 0.092; log rank-test = 2.87), graft survival was significantly higher in non-EAD patients (P = 0.008; log rank-test = 7.13). Bilirubin and INR on postoperative day 7 were identified as strong mortality predictors (Bilirubin HR = 1.71 [1.34, 2.16]; INR HR = 2.69 [0.51, 14.31]), in contrast to AST (HR = 0.91 [0.75, 1.10]). Similar results were achieved for graft loss estimation. A comparison with the Model for Early Allograft Function (MEAF) and the Liver Graft Assessment Following Transplantation (L-GrAFT) score identified a superior discrimination potential but lower specificity.Conclusion: Contrarily to AST, bilirubin and INR have strong predictive capacity for patient and graft survival. This fits well with the understanding, that bile duct injury and deprivation of synthetic function rather than hepatocyte injury are key factors in LT.

Liver transplantation (LT) survival rates have continued to improve over the last decades, mostly due to the reduction of mortality early after transplantation. The advancement is facilitating a liberalization of access to LT, with more patients with higher risk profiles being added to the waiting list. At the same time, the persisting organ shortage fosters strategies to rescue organs of high-risk donors. This is facilitated by novel technologies such as machine perfusion. Owing to these developments, reconsideration of the current and emerging endpoints for the assessment of the efficacy of existing and new therapies is warranted. While conventional early endpoints in LT have focused on the damage induced to the parenchyma, the fate of the bile duct and the recurrence of the underlying disease have a stronger impact on the long-term outcome. In light of this evolving landscape, we here attempt to reflect on the appropriateness of the currently used endpoints in the field of LT trials.

Chronic immunosuppression is associated with an increased risk of malignancy. The main objective of this study is to evaluate the incidence and effect of post-transplant malignancies (PTMs) following pancreas transplantation. The 348 first pancreas transplants performed between 1985 and 2015 were retrospectively analyzed in this study. Incidences of PTMs, as well as patient and graft survival, were evaluated. Out of 348 patients, 71 (20.4%) developed a PTM. Median time to diagnosis was 130 months. Thirty-six patients (50.7%) developed skin cancers (four patients with melanoma, 32 with NMSCs). Solid organ malignancy occurred in 25 (35.2%), hematologic malignancy in ten patients (14.1%). Affected patients were transplanted earlier [2000 (IQR 1993−2004) vs. 2003 (IQR 1999−2008), p &lt, 0.001]. No differences in induction therapy were seen, both groups demonstrated comparable patient and graft survival. Pancreas transplant recipients with solid organ and hematologic malignancies had a three- and six-fold increased hazard of death compared to those with skin cancers [aHR 3.04 (IQR 1.17–7.91), p = 0.023, aHR 6.07 (IQR 1.87–19.71), p = 0.003]. PTMs affect every fifth patient following pancreas transplantation. Skin cancers are the most common malignancies accounting for 50% of all PTMs. These results underscore the importance of close dermatologic follow-up.

In contrast to well-published data with acceptable long-term results in large cohorts of single renal transplant recipients aged >65 y (lit.), combined pancreas-kidney transplantation in recipients >50 y is discussed controversially. Some groups have identified older recipients as a high-risk group, demonstrating decreased patient and graft survival in this population.1-4 Nevertheless, several centers have reported results for pancreatic transplantation in older patients as being comparable to those for younger recipients with the age cutoff ranging from 50 to 60 y.5-10 At our center, we have long-term experience with a total of 655 pancreas transplants performed between 1979 and August 2020, whereby 21 recipients were over 60 y of age; the oldest was age 69 and in remarkably good general condition with good mental adherence and a strong wish to undergo simultaneous kidney-pancreas transplantation (SPK). We retrospectively analyzed patient, pancreas, and kidney graft survival, graft function, and complications at month 38 posttransplant.

Summary Donor cardiac arrest and cardiopulmonary resuscitation (CACPR) has been considered critically because of concerns over hypoperfusion and mechanical trauma to the donor organs. We retrospectively analyzed 371 first simultaneous pancreas–kidney transplants performed at the Medical University of Innsbruck between 1997 and 2017. We evaluated short‐ and long‐term outcomes from recipients of organs from donors with and without a history of CACPR. A total of 63 recipients received a pancreas and kidney graft from a CACPR donor. At 1, and 5‐years, patient survival was similar with 98.3%, and 96.5% in the CACPR and 97.0%, and 90.2% in the non‐CACPR group (log rank P = 0.652). Death‐censored pancreas graft survival was superior in the CACPR group with 98.3%, and 91.4% compared to 86.3%, and 77.4% (log rank P = 0.028) in the non‐CACPR group, which remained statistically significant even after adjustment [aHR 0.49 (95% CI 0.24–0.98), P = 0.044]. Similar relative risks for postoperative complications Clavien Dindo > 3a, pancreatitis, abscess, immunologic complications, delayed pancreas graft function, and relative length of stay were observed for both groups. Donors with a history of CACPR are, in the current practice, safe for transplantation. Stringent donor selection and short CPR durations may allow for outcomes surpassing those of donors without CACPR.

BACKGROUND Sarcopenia is an established risk factor predicting survival in chronically ill and trauma patients. We herein examine the assessment and clinical implication of sarcopenia in liver transplantation (LT). METHODS Computerized tomography scans from 172 patients waitlisted for LT were analyzed by applying 6 morphometric muscle scores, including 2 density indices (psoas density [PD] and skeletal muscle density [SMD]) and 4 scores based on muscle area (total psoas area, psoas muscle index, skeletal muscle area, and skeletal muscle index). RESULTS The prevalence of sarcopenia in our cohort ranged from 7.0% to 37.8%, depending on the score applied. Only sarcopenia as defined by the density indices PD and SMD (but not total psoas area, psoas muscle index, skeletal muscle area, or skeletal muscle index) revealed clinical relevance since it correlates significantly with postoperative complications (≥Grade III, Clavien-Dindo classification) and sepsis. Furthermore, sarcopenia predicted inferior patient and graft survival, with low muscle density (PD

The aim of our prospective clinical trial was to test a tissue staining technique (real-time confocal analysis [RTCA]) as a rapid assessment tool for donor kidney quality and function in human kidney transplantation.Tools for objective graft tissue viability assessment before kidney transplantation are lacking. RTCA has recently been established and tested in a pilot study using rodent kidneys.RTCA was performed in kidney biopsies stained with SYTO16/PI and WGA. A score between -3 (100% nonviable) and +3 (100% viable) describes the sum of viable cells divided by the number of nonviable cells per examined area (glomerulus, proximal, and distal tubules). The primary study endpoint was the delayed graft function (DGF).Seventy-one kidney transplant recipients were transplanted. The median recipient and donor age were 58.5 and 57 years, respectively. Cold ischemia time was 13.6 ± 4.7 hours; anastomosis time was 30.8 ± 8.7 minutes (mean ± SD). Overall, 23 (33.8%) patients developed DGF. The RTCA score was significantly lower in kidneys developing DGF -0.43 ± 1.78 versus no DGF 0.91 ± 2.17, P = 0.01. The Remuzzi score did not differ between DGF and no DGF, P = 0.13. Remuzzi score and RTCA score correlate inversely significantly; P = 0.004. In the multivariate analysis, solely RTCA score was revealed as a significant independent factor predicting DGF; P = 0.015, Wald = 5.95, odds ratio = 0.72, 95% confidence interval = 0.55 to 0.94.Our data demonstrate that RTCA is feasible and clinically meaningful. The RTCA score predicts DGF and is a valid option to be applied in renal transplantation.

Despite technical advances in surgical resection and postoperative management of the pancreas, surgical procedures of the pancreas are associated with a high rate of complications, resulting in a relevant morbidity and mortality. Early diagnosis and management of complications associated with pancreas surgery is mandatory, favoring a multidisciplinary approach. Interventional radiology offers minimal invasive techniques to manage post-surgical complications. These procedures are highlighted in this review, including percutaneous drainage of fluid collections, percutaneous transhepatic biliary interventions, arterial embolisation and fistula embolisation. Post-surgical complications of pancreatic surgery are effectively managed by radiological procedures, offering a feasible and safe treatment with low morbidity rates. Accurate patient selection is key to an effective management of clinical situations where these interventions represent the first line approach. Radiologic procedures allow for minimal invasive treatment of postoperative complications after pancreatic surgery, reducing the time of hospitalization and the time of recovery.

Despite clear advances in decreasing postoperative mortality below 4% after pancreatic resections in experienced centres, specific morbidity according to standardized definitions still remains high. While some recent multicentre studies have reported on complications after pancreatic surgery in Austria, detailed outcome data from single high-volume centres over longer time-periods are scarce. This study provides an in-depth picture of patient characteristics, indications, morbidity and mortality after pancreatic surgery in an Austrian tertiary referral centre. All patients undergoing curative intent resection between 2010 and 2017 at the Medical University of Innsbruck were evaluated. Patient characteristics and procedural details, overall and specific complications including postoperative pancreatic fistula (POPF), delayed gastric emptying (DGE) and post-pancreatectomy haemorrhage (PPH) rates according to accepted definitions are reported. Outcomes after pancreatic head resections, distal pancreatectomy and other types of resections are compared. Factors associated with severe and overall morbidity are evaluated by logistic regression modelling. A total of 343 patients underwent pancreatic resection, at a median of 64 years (53% males). Most common indications were pancreatic or bile-duct carcinoma (52%), benign/precursor lesions (22%) and neuroendocrine tumours (11%). The 90-day mortality was 2%; 90-day overall/severe morbidity was 66.2%/22.4%. POPF grade B/C occurred in 19.3%, PPH in 17.5% and DGE in 14.3%. Male gender was associated with severe morbidity, body mass index and procedures other than distal resections with overall morbidity. POPF and PPH were major causes for relaparotomy. Pancreatic resections in our centre are performed with low mortality, although morbidity still represents a relevant clinical problem, especially POPF and PPH.

BACKGROUND Early biliary complications (EBC) constitute a burden after pediatric liver transplantation frequently requiring immediate therapy. We aimed to assess the impact of EBC on short- and long-term patient and graft survival as well as post-transplant morbidity. METHODS We analyzed 121 pediatric liver transplantations performed between 1984 and 2019 at the Medical University of Innsbruck for the occurrence of early (

High alpha-fetoprotein levels after liver transplantation in hepatoblastoma: Does it matter?Hetzer Benjamin, M.D.1, Oberhuber Rupert, M.D.2, Entenmann Andreas, M.D.1, Schneeberger Stefan, M.D.2, Crazzolara Roman, M.D.1,*1Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria2Department of Visceral, Transplant and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria*Correspondence to:Roman Crazzolara, M.D., Department of Pediatrics, Anichstrasse 35, 6020 Innsbruck, Austria; Tel.: 0043-512-504-23600; Fax: 0043-512-504-24934; Email: roman.crazzolara@i-med.ac.at

BACKGROUND In an experimental murine liver clamping model, we aimed to investigate the efficacy of real-time confocal microscopy (RCM) in assessing viability of steatotic livers in comparison to standard assessment tools, including histopathological evaluation. METHODS C57Bl/6 mice were subjected to a methionine-choline-deficient diet causing nonalcoholic fatty liver disease or to Lieber DeCarli diet causing ethanol-induced liver injury. Untreated animals served as controls. Liver biopsies were analyzed following challenge with 45 min of warm ischemia time and either 4 h of reperfusion or 24 h of cold storage. Organ quality assessment was performed at defined time points by RCM, histological staining, measurement of serum alanine aminotransferase activity, and expression analyses of proinflammatory cytokines. Additionally, survival analysis was performed. RESULTS Cold as well as warm ischemia time resulted in a significant decrease in cell viability when compared with naive livers as well as nonischemic-challenged steatotic livers (P

The coronavirus disease 2019 (COVID-19) pandemic has changed life on a global scale. The numbers of transplantations have plummeted as a result of fear of disease transmission, recipient coronavirus disease 2019 infection, priority shift, and resource limitations. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) complicates transplantation because donor testing, (re)allocation of limited resources, and recipient testing may exceed permissible ischemia times. Normothermic machine perfusion (NMP) helps safely prolong liver preservation up to 38 hours. Additional time is essential under the current circumstances. Here we present the case of a 29-year-old liver transplant recipient in whom prolonged liver preservation required for SARS-CoV-2 screening was accomplished through NMP. Donor and recipient test results for SARS-CoV-2 were negative, and intensive care unit capacity was eventually available. The surgical procedure and postoperative course were uneventful. NMP can extend preservation times in liver transplantation while awaiting SARS-CoV-2 test results and available intensive care unit capacity.

Hypothermic machine perfusion (HMP) has been introduced as an alternative to static cold storage (SCS) in kidney transplantation, but its true benefit in the clinical routine remains incompletely understood. The aim of this study was to assess the effect of HMP vs. SCS in kidney transplantation. All kidney transplants performed between 08/2015 and 12/2019 (n = 347) were propensity score (PS) matched for cold ischemia time (CIT), extended criteria donor (ECD), gender mismatch, cytomegalovirus (CMV) mismatch, re-transplantation and Eurotransplant (ET) senior program. A total of 103 HMP and 103 SCS instances fitted the matching criteria. Prior to PS matching, the CIT was longer in the HMP group (17.5 h vs. 13.3 h, p &lt, 0.001), while the delayed graft function (DGF) rates were 29.8% and 32.3% in HMP and SCS, respectively. In the PS matched groups, the DGF rate was 64.1% in SCS vs. 31.1% following HMP: equivalent to a 51.5% reduction of the DGF rate (OR 0.485, 95% CI 0.318&ndash, 0.740). DGF was associated with decreased 1- and 3-year graft survival (100% and 96.3% vs. 90.8% and 86.7%, p = 0.001 and p = 0.008) or a 4.1-fold increased risk of graft failure (HR = 4.108, 95% CI: 1.336&ndash, 12.631, p = 0.014). HMP significantly reduces DGF in kidney transplantation. DGF remains a strong predictor of graft survival.

Organ transplantation is undergoing profound changes. Contraindications for donation have been revised in order to better meet the organ demand. The use of lower-quality organs and organs with greater preoperative damage, including those from donation after cardiac death (DCD), has become an established routine but increases the risk of graft malfunction. This risk is further aggravated by ischemia and reperfusion injury (IRI) in the process of transplantation. These circumstances demand a preservation technology that ameliorates IRI and allows for assessment of viability and function prior to transplantation. Oxygenated hypothermic and normothermic machine perfusion (MP) have emerged as valid novel modalities for advanced organ preservation and conditioning. Ex vivo prolonged lung preservation has resulted in successful transplantation of high-risk donor lungs. Normothermic MP of hearts and livers has displayed safe (heart) and superior (liver) preservation in randomized controlled trials (RCT). Normothermic kidney preservation for 24 h was recently established. Early clinical outcomes beyond the market entry trials indicate bioenergetics reconditioning, improved preservation of structures subject to IRI, and significant prolongation of the preservation time. The monitoring of perfusion parameters, the biochemical investigation of preservation fluids, and the assessment of tissue viability and bioenergetics function now offer a comprehensive assessment of organ quality and function ex situ. Gene and protein expression profiling, investigation of passenger leukocytes, and advanced imaging may further enhance the understanding of the condition of an organ during MP. In addition, MP offers a platform for organ reconditioning and regeneration and hence catalyzes the clinical realization of tissue engineering. Organ modification may include immunological modification and the generation of chimeric organs. While these ideas are not conceptually new, MP now offers a platform for clinical realization. Defatting of steatotic livers, modulation of inflammation during preservation in lungs, vasodilatation of livers, and hepatitis C elimination have been successfully demonstrated in experimental and clinical trials. Targeted treatment of lesions and surgical treatment or graft modification have been attempted. In this review, we address the current state of MP and advanced organ monitoring and speculate about logical future steps and how this evolution of a novel technology can result in a medial revolution.

Retrospective analysis of the long-term results of a randomized controlled trial comparing alemtuzumab (ALEM) and antithymocyte globulin (ATG) as induction therapy in simultaneous pancreas-kidney transplantation (SPK) to address individualized long-term immunosuppression. Between 2006 and 2010 a total of 30 SPKs were randomized to treatment with ALEM plus tacrolimus (TAC) monotherapy (Group A, n=14) versus ATG induction plus TAC, mycophenolate mofetil (MMF) and steroids (Group B, n=16), followed by individualized long-term immunosuppression. We here present the long-term results for graft survival, graft function, and major complications. The 9-year patient survival rates in Groups A and Group B were 92.9% and 86.7% respectively; pancreas graft survival was 75.0% and 65.0% respectively; renal graft survival was 83.1% and 93.8% respectively. Long-term graft function was excellent with a creatinine of 1.5 mg/dL and 1.4 mg/dL, fasting glycemia of 104 mg/dL and 102 mg/dL, hemoglobin (Hb) A1c of 5.4 g% and 5.6 g% in Group A and Group B, respectively. Major complications were comparable in both groups. Good long-term results for patient, pancreas graft and kidney graft survival were achieved in both groups with individually adapted maintenance immunosuppression. ALEM is a valid induction therapy.

While both living donation and donation after circulatory death provide alternative opportunities for organ transplantation, donation after donor brain death (BD) still represents the major source for solid transplants. Unfortunately, the irreversible loss of brain function is known to induce multiple pathophysiological changes, including hemodynamic as well as hormonal modifications, finally leading to a systemic inflammatory response. Models that allow a systematic investigation of these effects in vivo are scarce. We present a murine model of BD induction, which could aid investigations into the devastating effects of BD on allograft quality. After implementing intra-arterial blood pressure measurement via the common carotid artery and reliable ventilation via a tracheostomy, BD is induced by steadily increasing intracranial pressure using a balloon catheter. Four hours after BD induction, organs may be harvested for analysis or for further transplantation procedures. Our strategy enables the comprehensive analysis of donor BD in a murine model, therefore allowing an in-depth understanding of BD-related effects in solid organ transplantation and potentially paving the way to optimized organ preconditioning.

Primary focal segmental glomerulosclerosis (FSGS) recurs in up to 55% of patients after kidney transplantation. Herein we report the successful management of recurrent FSGS. A 5‐year‐old boy with primary FSGS received a deceased donor renal transplant. Immediate and fulminant recurrence of FSGS caused anuric graft failure that was resistant to plasmapheresis and rituximab. After exclusion of structural or immunologic damage to the kidney by repeated biopsies, the allograft was retrieved from the first recipient on day 27 and transplanted into a 52‐year‐old second recipient who had vascular nephropathy. Immediately after retransplantation, the allograft regained function with excellent graft function persistent now at 3 years after transplant. After 2 years on hemodialysis, the boy was listed for kidney retransplantation. To prevent FSGS recurrence, pretreatment with ofatumumab was performed. Nephrotic range proteinuria still occurred after the second transplantation, which responded, however, to daily plasma exchange in combination with ofatumumab. At 8 months after kidney retransplantation graft function is good. The clinical course supports the hypothesis of a circulating permeability factor in the pathogenesis of FSGS. Successful ofatumumab pretreatment implicates a key role of B cells. Herein we provide a description of successful management of kidney failure by FSGS, carefully avoiding waste of organs., Successful management of recurrent primary focal segmental glomerulosclerosis after kidney transplantation includes retransplantation of an allograft that failed in the first recipient due to disease recurrence into a second recipient and ofatumumab pretreatment before kidney retransplantation in the patient with fulminant recurrence of focal segmental glomerulosclerosis in the first graft.

Background: Heart failure (HF) survival has improved, and nowadays, many patients with HF die of noncardiac causes, including cancer. Our aim was to investigate whether a causal relationship exists between HF and the development of cancer. Methods: HF was induced by inflicting large anterior myocardial infarction in APC min mice, which are prone to developing precancerous intestinal tumors, and tumor growth was measured. In addition, to rule out hemodynamic impairment, a heterotopic heart transplantation model was used in which an infarcted or sham-operated heart was transplanted into a recipient mouse while the native heart was left in situ. After 6 weeks, tumor number, volume, and proliferation were quantified. Candidate secreted proteins were selected because they were previously associated both with (colon) tumor growth and with myocardial production in post–myocardial infarction proteomic studies. Myocardial gene expression levels of these selected candidates were analyzed, as well as their proliferative effects on HT-29 (colon cancer) cells. We validated these candidates by measuring them in plasma of healthy subjects and patients with HF. Finally, we associated the relation between cardiac specific and inflammatory biomarkers and new-onset cancer in a large, prospective general population cohort. Results: The presence of failing hearts, both native and heterotopically transplanted, resulted in significantly increased intestinal tumor load of 2.4-fold in APC min mice (all P P =0.002 and P =0.016, respectively). We identified several proteins (including serpinA3 and A1, fibronectin, ceruloplasmin, and paraoxonase 1) that were elevated in human patients with chronic HF (n=101) compared with healthy subjects (n=180; P Conclusions: We demonstrate that the presence of HF is associated with enhanced tumor growth and that this is independent of hemodynamic impairment and could be caused by cardiac excreted factors. A diagnosis of HF may therefore be considered a risk factor for incident cancer.

Summary Background Owing to remarkable improvements of surgical techniques and associated specialities, liver surgery has become the standard of care for hepatocellular carcinoma and cholangiocarcinoma. Although applied with much greater safety, hepatic resections for primary liver tumours remain challenging and need to be integrated in a complex multidisciplinary treatment approach. Methods This literature review gives an update on the recent developments regarding basics of open and laparoscopic liver surgery and surgical strategies for primary liver tumours. Results Single-centre reports and multicentre registries mainly from Asia and Europe dominate the surgical literature on primary liver tumours, but the numbers of randomized trials are slowly increasing. Perioperative outcomes of open liver surgery for hepatocellular and cholangiocellular carcinoma have vastly improved over the last decades, accompanied by some progress in terms of oncological outcome. The laparoscopic approach is increasingly being applied in many centres, even for patients with underlying liver disease, and may result in decreased morbidity. Liver transplantation represents a cornerstone in the treatment of early hepatocellular carcinoma and is indispensable to achieve long-term survival. In contrast, resection remains the gold standard for cholangiocarcinoma in most countries, but interventional techniques are on the rise. Conclusion Liver surgery for primary tumours is complex, with a need for high expertise in a multidisciplinary team to achieve acceptable outcomes. Technical developments and clinical stratification tools have optimized individual care, but further improvements in oncological survival will likely require enhanced pre- and postoperative systemic and local treatment options.

Mitochondria sense changes resulting from the ischemia and subsequent reperfusion of an organ and mitochondrial reactive oxygen species (ROS) production initiates a series of events, which over time result in the development of full-fledged ischemia-reperfusion injury (IRI), severely affecting graft function and survival after transplantation. ROS activate the innate immune system, regulate cell death, impair mitochondrial and cellular performance and hence organ function. Arresting the development of IRI before the onset of ROS production is currently not feasible and clinicians are faced with limiting the consequences. Ex vivo machine perfusion has opened the possibility to ameliorate or antagonize the development of IRI and may be particularly beneficial for extended criteria donor organs. The molecular events occurring during machine perfusion remain incompletely understood. Accumulation of succinate and depletion of adenosine triphosphate (ATP) have been considered key mechanisms in the initiation; however, a plethora of molecular events contribute to the final tissue damage. Here we discuss how understanding mitochondrial dysfunction linked to IRI may help to develop novel strategies for the prevention of ROS-initiated damage in the evolving era of machine perfusion.

Background Several studies in solid organ transplantation have shown a correlation between donor and recipient sex mismatch and risk of graft loss. In this study, we aimed to analyze the impact of donor and recipient sex matching on patient and pancreas graft survival in a large single‐center cohort. Methods We retrospectively analyzed all first simultaneous pancreas‐kidney transplants performed between 1979 and 2017 at the Medical University of Innsbruck. Results Of 452 patients, 54.6% (247) received a sex‐matched transplant. Patient survival (P = .86), death‐censored pancreas graft survival (dcPGS, P = .26), and death‐censored kidney graft survival (dcKGS, P = .24) were similar between the sex‐matched and sex‐mismatched groups. Patient survival and dcPGS at 1, 5, and 15 years were 95.9%, 90.0%, and 62.1% and 86.1%, 77.1%, and 56.7% in the sex‐matched group and 93.6%, 86.2%, and 62.4% and 83.1%, 73.3%, and 54.3% in the sex‐mismatched group. Sex matching led to a lower odds of severe postoperative complications (41.2% vs 49.0%; OR 0.57, 95%CI 0.33‐0.97; P = .038); however, no increased odds of other adverse postoperative outcomes was detected. Conclusion Our study demonstrates that sex matching reduced the odds of postoperative complications but did not impact other early and late outcome parameters in our cohort.

OBJECTIVES Ischaemia and subsequent reperfusion during heart transplantation inevitably result in donor organ injury. Toll-like receptor (TLR)-3 is a pattern recognition receptor activated by viral and endogenous RNA released by injured cells. We hypothesized that ischaemia/reperfusion injury (IRI) leads to RNA release with subsequent TLR3 activation in transplanted hearts. METHODS Human endothelial cells were subjected to IRI and treated with TLR3 agonist polyinosinic–polycytidylic acid or a TLR3/double-stranded RNA complex inhibitor. TLR3 activation was analysed using reporter cells. Gene expression profiles were evaluated via next-generation sequencing. Neutrophil adhesion was assessed in vitro. Syngeneic heart transplantation of wild-type or Tlr3−/− mice was performed following 9 h of cold ischaemia. Hearts were analysed for inflammatory gene expression, cardiac damage, apoptosis and infiltrating leucocytes. RESULTS IRI resulted in RNA release with subsequent activation of TLR3. Treatment with a TLR3 inhibitor abrogated the inflammatory response upon IRI. In parallel, TLR3 stimulation caused activation of the inflammasome. Endothelial IRI resulted in TLR3-dependent adhesion of neutrophils. Tlr3−/− animals showed reduced intragraft and splenic messenger ribonucleic acid (mRNA) expression of proinflammatory cytokines, resulting in decreased myocardial damage, apoptosis and infiltrating cells. Tlr3 deficiency protected from cardiac damage, apoptosis and leucocyte infiltration after cardiac transplantation. CONCLUSIONS We uncover the release of RNA by injured cells with subsequent activation of TLR3 as a crucial pathomechanism of IRI. Our data indicate that TLR3 represents a novel target in the prevention of IRI in solid organ transplantation.

Transplantation represents the treatment of choice for many end-stage diseases but is limited by the shortage of healthy donor organs. Ex situ normothermic machine perfusion (NMP) has the potential to extend the donor pool by facilitating the use of marginal quality organs such as those from donors after cardiac death (DCD) and extended criteria donors (ECD). NMP provides a platform for organ quality assessment but also offers the opportunity to treat and eventually regenerate organs during the perfusion process prior to transplantation. Due to their anti-inflammatory, immunomodulatory and regenerative capacity, mesenchymal stem cells (MSCs) are considered as an interesting tool in this model system. Only a limited number of studies have reported on the use of MSCs during ex situ machine perfusion so far with a focus on feasibility and safety aspects. At this point, no clinical benefits have been conclusively demonstrated, and studies with controlled transplantation set-ups are urgently warranted to elucidate favorable effects of MSCs in order to improve organs during ex situ machine perfusion.

Donor organ quality affects long term outcome after renal transplantation. A variety of prognostic molecular markers is available, yet their validity often remains undetermined. A network-based molecular model reflecting donor kidney status based on transcriptomics data and molecular features reported in scientific literature to be associated with chronic allograft nephropathy was created. Significantly enriched biological processes were identified and representative markers were selected. An independent kidney pre-implantation transcriptomics dataset of 76 organs was used to predict estimated glomerular filtration rate (eGFR) values twelve months after transplantation using available clinical data and marker expression values. The best-performing regression model solely based on the clinical parameters donor age, donor gender, and recipient gender explained 17% of variance in post-transplant eGFR values. The five molecular markers EGF, CD2BP2, RALBP1, SF3B1, and DDX19B representing key molecular processes of the constructed renal donor organ status molecular model in addition to the clinical parameters significantly improved model performance (p-value = 0.0007) explaining around 33% of the variability of eGFR values twelve months after transplantation. Collectively, molecular markers reflecting donor organ status significantly add to prediction of post-transplant renal function when added to the clinical parameters donor age and gender.

A comparative analysis of inflammation between solid organs following donor brain death (BD) is still lacking and the detailed influence of BD accelerating ischaemia-reperfusion injury (IRI) post-transplantation remains to be addressed. Applying a murine model of BD, we demonstrated that 4 h after BD organs were characterized by distinct inflammatory expression patterns. For instance, lipocalin 2 (LCN2), a marker of acute kidney injury, was selectively induced in BD livers but not in kidneys. BD further resulted in significantly reduced frequencies of CD3(+) CD4(+) , CD3(+) CD8(+) T cells and NKp46(+) NK cells in the liver, whereas BD kidneys and hearts were characterized by significantly lower frequencies of conventional dendritic cells (cDCs). Syngeneic models of kidney (KTx) and heart transplantation (HTx) illustrated stronger gene expression in engrafted BD hearts only, but 20 h post-transplantation both organs displayed comparable intragraft lymphocyte frequencies, except for NK cells and graft function. Moreover, the complement factor C3d deposit detected in small vessels and capillaries in cardiac syngrafts did not significantly differ between BD and sham-transplanted groups. Finally, no further influence of donor BD on graft survival was detected in an allogeneic heart transplantation setting (C57BL/6 grafts into BALB/c recipients). We show for the first time that BD organs are characterized by a varying inflammatory profile; however, BD does not accelerate IRI in syngeneic KTx and HTx. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Background— Organ transplantation has seen an increased use of organs from older donors over the past decades in an attempt to meet the globally growing shortage of donor organs. However, inferior transplantation outcomes when older donor organs are used represent a growing challenge. Methods and Results— Here, we characterize the impact of donor age on solid-organ transplantation using a murine cardiac transplantation model. We found a compromised graft survival when older hearts were used. Shorter graft survival of older hearts was independent of organ age per se, because chimeric young or old organs repopulated with young passenger leukocytes showed comparable survival times. Transplantation of older organs triggered more potent alloimmune responses via intragraft CD11c + dendritic cells augmenting CD4 + and CD8 + T-cell proliferation and proinflammatory cytokine production, particularly that of interleukin-17A. Of note, depletion of donor CD11c + dendritic cells before engraftment, neutralization of interleukin-17A, or transplantation of older hearts into IL-17A −/− mice delayed rejection and reduced alloimmune responses to levels observed when young hearts were transplanted. Conclusions— These results demonstrate a critical role of old donor CD11c + dendritic cells in mounting age-dependent alloimmune responses with an augmented interleukin-17A response in recipient animals. Targeting interleukin-17A may serve as a novel therapeutic approach when older organs are transplanted.

Despite a continuously growing knowledge of the impact of factors on kidney graft function, such as donor age, body mass index, and cold ischemia time, few data are available regarding anastomosis time (AT) and its impact on long-term results. We investigated whether surgical AT correlates with patient and graft survival after kidney transplantation performing a retrospective analysis of 1245 consecutive deceased donor kidney transplantations between 01/2000 and 12/2010 at Innsbruck Medical University. Kaplan-Meier and log-rank analyses were carried out for 1- and 5-year patient and graft survival. AT was defined as time from anastomosis start until reperfusion. Median AT was 30 min. Five-year survival of allografts with an AT >30 min was 76.6% compared with 80.6% in the group with AT

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the availability of the widest range of molecular probes and reagents to perform in vivo as well as in vitro studies. Based on our experience with various murine transplantation models, we developed a heterotopic pancreas transplantation model in mice with the intent to analyze mechanisms underlying severe ischemia reperfusion injury-associated early graft damage. In contrast to previously described techniques using suture techniques, herein we describe a new procedure using a non-suture cuff technique. In recent years, we have performed more than 300 pancreas transplantations in mice with an overall success rate of >90%, a success rate never described before in mouse pancreas transplantation. The backbone of this non-suture cuff technique for graft revascularization consists of two major steps: (I) pulling the recipient vessel over a polyethylene/polyamide cuff and fixing it with a circumferential ligature, and (II) placing the donor vessel over the everted recipient vessel and fixing it with a second circumferential ligature. The resultant continuity of the endothelial layer results in less thrombogenic lesions with high patency rates and, finally, high success rates. In this model, arterial anastomosis is achieved by pulling the abdominal aorta of the donor graft over the everted common carotid artery of the recipient animal. Venous drainage of the graft is achieved by pulling the portal vein of the graft over the everted external jugular vein of the recipient. This manuscript provides details and crucial steps of the organ recovery and organ implantation procedures, which will allow researchers with microsurgical skills to perform the transplantation successfully in their laboratories.

Background Bile leakage (BL) is a frequent and severe complication following liver surgery. The aim of this study was to evaluate risk factors for BL, related other complications and association with long-term survival. Methods This study included all patients undergoing hepatectomy in a single centre from 2005 to 2016. Perioperative risk factors related to BL were identified using univariable and multivariable analysis. Kaplan-Meier method was used for survival analysis. Results BL occurred in 48 of 458 patients (11%). BLs were more frequent in patients after major hepatectomy (p = 0.001). Portal vein embolization, bilioenteric-anastomosis, lymphadenectomy, vascular reconstruction and operative time were significant factors for developing BL. Comparing patients with or without BL, BL was more commonly associated with other postoperative complications (p = 0.001), especially acute kidney failure and surgical-site-infections. There was no difference in 90-day-mortality (p = 0.124). The median disease-free survival was comparable (17 vs. 15 months, p = 0.976), also no difference was observed when stratifying for different tumour entities. There was no difference in median overall survival (OS) among malignant disease (35 vs. 47 months, p = 0.200) and in 3-year OS (46% vs. 59%). Multivariate analysis confirmed that postoperative liver failure and major hepatectomy were risk factors for reduced OS (p = 0.010). Conclusions Many concerns have been raised regarding tumour progression after major complications. In this study, we only found a relevant influence of BL on OS in pCC, whereas no association was seen in other cancer types, indicating that tumour progression might be triggered by BL in cancer types arising from the bile ducts itself.

Ischemia and reperfusion contribute to substantial organ damage in transplantation. Clinically feasible measures for the prevention thereof are scarce. We tested whether rinsing rodent hearts with the antioxidant bilirubin ameliorates ischemia reperfusion injury (IRI). Left ventricular end-diastolic pressure (LVEDP), left ventricular developed pressure (LVDevP), rate per pressure product (RPP), coronary flow, maximum (+dP/dt) and minimum (-dP/dt) rate of contraction were analyzed in Lewis rat hearts rinsed with bilirubin prior to reperfusion on a Langendorff apparatus after 12 h of cold ischemia. In vivo, isogenic C57Bl/6 mouse hearts rinsed with bilirubin were transplanted after 12 h of cold ischemia. Cardiac function and apoptosis were assessed 24 h after reperfusion. Heart lysates recovered 15 min after reperfusion were probed for the total and the phosphorylated forms of extracellular signal-related protein kinases (ERK), JNK, p38-MAPK, and Akt. In isolated perfused hearts, bilirubin rinse resulted in significantly lower LVEDP and improved LVDevP, RPP, coronary flow, +dP/dt and -dP/dt. In vivo, after reperfusion, all mitogen-activated protein kinases (MAPKs) were suppressed significantly by bilirubin pretreatment. Bilirubin rinse improved cardiac scores (3.4 ± 0.5 vs. 2.0 ± 1.0 in controls, P < 0.05) and significantly suppressed apoptosis. Ex vivo administration of bilirubin to heart grafts prior reperfusion ameliorates IRI and provides a simple and effective tool to ameliorate outcome in heart transplantation.

BACKGROUND Allogeneic bone marrow transplantation is under investigation for a range of nonmalignant indications, including tolerance induction through mixed chimerism. This strategy has so far been tested experimentally only in young recipients. Due to immunosenescence, older patients have an increase in memory T cells (TMEM) as well as other alterations to their immune system, which may influence the potential to induce tolerance. We therefore investigated the impact of immunosenescence on chimerism-based tolerance induction. METHODS Groups of young (2 months) and old (12 months) C57BL/6 recipients received BALB/c bone marrow under nonmyeloablative (3 Gy) and minimal (1 Gy) total body irradiation and treatment with costimulation blockade, T-cell depletion, or rapamycin. Multilineage chimerism, clonal deletion, and lymphocyte subsets were analyzed by flow cytometry. Tolerance was assessed by skin and heart grafts and enzyme-linked immunospot, intracellular cytokine, and mixed lymphocyte reaction assays. RESULTS Unexpectedly, chimerism and tolerance were established in old recipients with comparable-and in some cases increased-efficacy as in young recipients employing costimulation blockade-based or T-cell depletion-based conditioning with 1 or 3 Gy total body irradiation. TMEM reactivity in (naive) old mice was augmented in response to polyclonal but not to allogeneic stimulation, providing a mechanistic underpinning for the susceptibility to chimerism induction despite increased TMEM frequencies. Tolerance in old recipients was associated with peripheral and central clonal deletion and a higher frequency of regulatory T cells. CONCLUSION Advanced age does not impair bone marrow engraftment, thereby widening the clinical potential of experimental protocols inducing transplantation tolerance through mixed chimerism.

Ischemia-reperfusion injury is a primarily non-allospecific event leading to the depletion of the essential nitric oxide synthase cofactor and potent antioxidant tetrahydrobiopterin. Suboptimal concentrations of tetrahydrobiopterin result in a reduced biosynthesis of nitric oxide leading to vascular endothelial dysfunction. Tetrahydrobiopterin supplementation has been shown to protect from this pathological state in a plethora of cardiovascular diseases including transplant-related ischemia-reperfusion injury. Even though still controversially discussed, there is increasing evidence emerging from both human as well as animal studies that tetrahydrobiopterin-mediated actions rely on its nitric oxide synthase cofactor activity rather than on its antioxidative properties. Herein, we review the current literature regarding the role of tetrahydrobiopterin in ischemia-reperfusion injury including our experience acquired in a murine pancreas transplantation model.

BACKGROUND Simultaneous pancreas-kidney (SPK) transplantation is widely accepted as an optimal therapeutic option for patients with type 1 diabetes mellitus (T1DM) and end-stage renal disease, but the indication for patients with type 2 diabetes mellitus (T2DM) is still controversially discussed. METHODS Twenty-one T2DM recipients of a first combined pancreas-kidney graft performed at our center during a 9-year period were retrospectively analyzed with regard to demographic characteristics; cardiovascular risk factors; surgical, immunological, and infectious complications; and patient and graft survivals and compared with T1DM recipients (n=195) and 32 T2DM patients who received a kidney transplant alone (KTA) during the same period. RESULTS Patient survival at 1 and 5 years was 96.9% and 91.6% for the T1DM group, 90.5% and 80.1% for the T2DM group, and 87.1% and 54.2% for the T2DM KTA group, respectively (P

The inferiority of organs from brain dead donors is reflected by impaired graft survival and patient outcome. Brain death effects hemodynamic stability, hormonal changes, and neuroimmunologic effects and unleashes a cascade of inflammatory events. Despite considerable efforts in experimental and clinical research, most of the mechanisms linked to brain death are only appreciated on a descriptive level. This overview presents our current understanding of the pathophysiology and consequences of brain death on organ injury and summarizes available therapeutic interventions.

Tetrahydrobiopterin (BH4) is an essential cofactor for the nitric oxide (NO) synthases and represents a critical determinant of NO production. BH4 depletion during ischemia leads to the uncoupling of the synthases, thus contributing to reperfusion injury due to increased superoxide formation. To examine whether BH4 supplementation attenuates ischemia–reperfusion injury, we clamped the left renal arteries of male Lewis rats immediately following right-side nephrectomy. BH4 tissue levels significantly decreased after 45 min of warm ischemia compared with levels in non-ischemic controls. Histopathology demonstrated significant tubular damage and increased peroxynitrite formation. Intravital fluorescent microscopy found perfusion deficits in the microvasculature and leakage of the capillary mesh. Supplemental BH4 treatment before ischemia significantly reduced ischemia-induced renal dysfunction, and decreased tubular histologic injury scores and peroxynitrite generation. BH4 also significantly improved microcirculatory parameters such as functional capillary density and diameter. These protective effects of BH4 on microvasculature were significantly correlated with its ability to abolish peroxynitrite formation. We suggest that BH4 significantly protects against acute renal failure following ischemia reperfusion. Whether BH4 has a therapeutic potential will require more direct testing in humans.

Transplant vasculopathy (TV) represents a major obstacle to long-term graft survival and correlates with severity of ischemia reperfusion injury (IRI). Donor administration of the nitric oxide synthases (NOS) co-factor tetrahydrobiopterin has been shown to prevent IRI. Herein, we analysed whether tetrahydrobiopterin is also involved in TV development. Using a fully allogeneic mismatched (BALB/c to C57BL/6) murine aortic transplantation model grafts subjected to long cold ischemia time developed severe TV with intimal hyperplasia (α-smooth muscle actin positive cells in the neointima) and endothelial activation (increased P-selectin expression). Donor pretreatment with tetrahydrobiopterin significantly minimised these changes resulting in only marginal TV development. Severe TV observed in the non-treated group was associated with increased protein oxidation and increased occurrence of endothelial NOS monomers in the aortic grafts already during graft procurement. Tetrahydrobiopterin supplementation of the donor prevented all these early oxidative changes in the graft. Non-treated allogeneic grafts without cold ischemia time and syngeneic grafts did not develop any TV. We identified early protein oxidation and impaired endothelial NOS homodimer formation as plausible mechanistic explanation for the crucial role of IRI in triggering TV in transplanted aortic grafts. Therefore, targeting endothelial NOS in the donor represents a promising strategy to minimise TV.

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice(1-3). This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates(4). Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient(5). Herein, we provide additional details of this technique to supplement the video.

Objective: Aim of this study was to identify the nitric oxide synthase (NOS) isoform involved in early microcirculatory derangements following solid organ transplantation. Background: Tetrahydrobiopterin donor treatment has been shown to specifically attenuate these derangements following pancreas transplantation, and tetrahydrobiopterin-mediated protective effects to rely on its NOS-cofactor activity, rather than on its antioxidant capacity. However, the NOS-isoform mainly involved in this process has still to be defined. Methods: Using a murine pancreas transplantation model, grafts lacking one of the three NOS-isoforms were compared to grafts from wild-type controls. Donors were treated with either tetrahydrobiopterin or remained untreated. All grafts were subjected to 16 h cold ischemia time and transplanted into wild-type recipients. Following 4 h graft reperfusion, microcirculation was analysed by confocal intravital fluorescence microscopy. Recipient survival was monitored for 50 days. Results: Transplantation of the pancreas from untreated wild-type donor mice resulted in microcirculatory damage of the transplanted graft and no recipient survived more than 72 h. Transplanting grafts from untreated donor mice lacking either endothelial or inducible NOS led to similar outcomes. In contrast, donor treatment with tetrahydrobiopterin prevented microcirculatory breakdown enabling long-term survival. Sole exception was transplantation of grafts from untreated donor mice lacking neuronal NOS. It resulted in intact microvascular structure and long-term recipient survival, either if donor mice were untreated or treated with tetrahydrobiopterin. Conclusion: We demonstrate for the first time the crucial involvement of neuronal NOS in early microcirculatory derangements following solid organ transplantation. In this model, protective effects of tetrahydrobiopterin are mediated by targeting this isoform.

Summary Tetrahydrobiopterin has been shown to efficiently abrogate ischemia reperfusion injury (IRI). However, it is unclear, whether its beneficial action relies on cofactor activity of one of the five known tetrahydrobiopterin-dependent reactions or on its antioxidative capacity. We therefore compared tetrahydrobiopterin with the pterin derivate tetrahydroneopterin (similar biochemical properties, but no nitric oxide synthase cofactor activity) and the antioxidants vitamin C and 5-methyltetrahydrofolate. Donor mice were pretreated with tetrahydrobiopterin, tetrahydroneopterin, vitamin C, or 5-methyltetrahydrofolate. Pancreatic grafts were subjected to 16-h cold ischemia time and implanted in syngeneic recipients. Untreated and nontransplanted animals served as controls. Following 2-h reperfusion, microcirculation was analyzed by intravital fluorescence microscopy. Graft damage was assessed by histology and nitrotyrosine immunostaining, and tetrahydrobiopterin levels were determined by HPLC. Recipient survival served as ultimate readout. Prolonged cold ischemia time resulted in microcirculatory breakdown. Only tetrahydrobiopterin pretreatment succeeded to preserve the capillary net, whereas all other compounds showed no beneficial effects. Along with increased intragraft tetrahydrobiopterin levels during recovery and implantation, only tetrahydrobiopterin pretreatment led to significant reduction of IRI-related parenchymal damage enabling recipient survival. These results show a striking superiority of tetrahydrobiopterin in preventing lethal IRI compared with related compounds and suggest nitric oxide synthases as treatment target.