Treatment Of Donor Organs Research Articles

Ex vivo perfusion in lung transplantation and removal of HCV: the next level.

The large gap between high demand and low availability of lungs is still a limiting factor for lung transplantation which leads to important mortality rates on the waiting list. In the last years, with the advent of potent direct-acting antivirals (DAAs), donors carrying active hepatitis C (HCV) infection became an important source in expanding the donor pool. Recent clinical trials exploring different treatment regimens post-transplantation when using HCV-positive abdominal and thoracic organs into HCV-negative recipients have shown encouraging results. Although early data shows no toxicity and similar survival rates when compared to non-HCV organ transplantation, long-term outcomes evaluating the effect of either the transmission of HCV into the recipients or the deliberate use of DAAs to treat the virus remains absent. An important and innovative strategy to overcome this limitation is the possibility of mitigating viral transmission with the use of ex vivo donor organ treatment prior to transplantation. Recent pre-clinical and clinical studies explore the use of ex vivo perfusion and the removal of HCV prior to transplantation with the addition of other innovative therapies, which will be reviewed in this article.

Prevention of viral transmission during lung transplantation with hepatitis C-viraemic donors: an open-label, single-centre, pilot trial

A substantial proportion of organ donors test positive for hepatitis C virus (HCV) infection. To date, only a few studies have evaluated the safety of using lungs from these donors for transplantation, and no direct interventions to donor organs have been done with the aim of preventing HCV transmission via organ transplantation. We aimed to assess the safety and efficacy of lung transplantation in humans from HCV-positive donors to HCV-negative recipients after application of ex-vivo lung perfusion (EVLP) plus ultraviolet C (UVC) perfusate irradiation. We did a single centre, prospective, open-label, non-randomised trial in which donor lungs from HCV-viraemic donors (HCV-positive) were transplanted into HCV-negative recipients at Toronto General Hospital, University Health Network (Toronto, ON, Canada). Donors were younger than 65 years old and tested positive for HCV by nucleic acid testing. Donors who tested positive for hepatitis B virus, HIV, human T-lymphotropic virus 1 or 2 were excluded. Recipients were on the lung transplant waiting list without significant liver disease (stage 2 fibrosis or higher were excluded) or active HCV infection. Before implantation, all HCV-positive donor lungs were treated with EVLP with or without UVC perfusate irradiation to reduce the concentration of HCV RNA and infectivity. For the first week after transplantation, patients' HCV RNA blood concentrations were measured once daily, then once per week for 12 weeks. All patients received 12 weeks of oral sofosbuvir 400 mg plus velpatasvir 100 mg, starting at least 2 weeks after transplantation. The primary endpoint was a composite of survival and HCV-free status at 6 months after transplantation in all patients who received HCV-positive lungs. Patient outcomes such as survival, time in hospital, and incidence of acute rejection were compared between those receiving HCV-positive lungs and all patients who received HCV-negative lung transplants during the study period. The study is registered with ClinicalTrials.gov, NCT03112044. From Oct 1, 2017, to Nov 1, 2018, 209 patients had a transplantation; of 27 donors who were HCV-positive and initially considered, 22 were suitable for transplantation. The remaining 187 donors were HCV-negative. Before implantation, 11 of the HCV-positive donor lungs were treated with EVLP alone and the other 11 were treated with EVLP plus UVC. Lung disease, urgency status, and positive donor-recipient HLA crossmatch were similar between the patients who received HCV-positive and HCV-negative lungs. 20 (91%) patients in the HCV-positive group developed HCV viraemia within the first week after transplantation and had sofosbuvir plus velpatasvir treatment, starting at a median of 21 days after transplantation (IQR 16·76-24·75). Donor organ treatment with EVLP plus UVC was associated with significantly lower recipient viral loads in blood within the first week after transplantation than with EVLP alone (median of 167 IU/mL [IQR 20-12 000] vs 4390 IU/mL [1170-112 000] at day 7; p=0·048) and prevented transmission in two (18%) of 11 patients. All 20 infected patients achieved negative HCV PCR within 6 weeks of treatment initiation. The primary endpoint of survival and HCV-free status at 6 months after transplantation was achieved in 19 (86%) of 22 patients in the HCV-positive group. 6-month survival was 95% in recipients receiving lungs from HCV-viraemic donors versus 94% in recipients receiving lungs from HCV-negative donors. The most common grade 3-4 adverse events in the HCV-positive group were respiratory complications (five [23%]) and infections (four [18%]). Serious adverse events requiring admission to hospital occurred in ten (45%) patients. One (5%) patient who did not develop HCV infection died at day 31 from multiorgan failure related to pseudomonas sepsis. Two patients presented with HCV relapse within 3 months after sofosbuvir plus velpatasvir completion and required retreatment. Early and intermediate clinical outcomes were not significantly different between patients receiving viraemic HCV donor lungs and HCV-negative donor lungs. Donor organ treatment with UVC perfusate irradiation during EVLP significantly decreased HCV viral loads within the first 7 days after transplantation and shows the proof-of-concept for a novel approach of minimising viral load ex vivo before transplantation, with intent of preventing donor-recipient transmission. Canadian Institutes of Health Research.

Lung Transplantation Using Hepatitis C Viremic Donors: An Open-Label Single Center Pilot Trial of Prevention of Viral Transmission

Background: A significant proportion of organ donors currently test positive for hepatitis C virus (HCV) infection. To date, only a few studies have evaluated the safety of using lungs from these donors for transplantation, and no direct interventions to donor organs have been performed with the aim of preventing HCV transmission via organ transplantation. Methods: We performed a single center prospective non-randomized trial where donor lungs from HCV viremic donors were transplanted into HCV negative (HCV-ve) recipients. Outcomes of study recipients were compared to patients receiving HCV-ve donors. Primary endpoints were survival and HCV status at 6 months after transplantation. Prior to implantation, all donor lungs were treated with ex vivo lung perfusion (EVLP) with (n=11) or without (n=11) ultraviolet C (UVC) perfusate irradiation to reduce HCV RNA levels and infectivity. All patients becoming viremic received 12 weeks of sofosbuvir/velpatasvir (S/V) starting at least 2 weeks after transplantation. Findings: During the 13-month study period, 22 patients were transplanted using viremic HCV donors and 187 with HCV-ve donors. Recipient age, lung disease, urgency status and positive donor-recipient HLA crossmatch were similar between the 2 groups. Post-transplant outcomes such as primary graft dysfunction grades, ICU and hospital length of stay, and survival were similar between the 2 groups. Twenty patients (91%) developed HCV viremia within the first week after transplantation and underwent S/V treatment starting at a median of 21 days after transplantation (range 14-71 days). Donor organ treatment with EVLP+UVC was associated with significantly lower recipient viral loads in blood within the first week after transplantation, and prevention of transmission in 2/11 patients. All infected patients achieved negative HCV PCR within 6 weeks of treatment initiation. Two patients presented with HCV relapse within 3 months after S/V completion requiring retreatment. Interpretation: Early and intermediate-term clinical outcomes using viremic HCV donors were similar to patients receiving HCV-ve donor lungs. Donor organ treatment using UVC perfusate irradiation during EVLP showed a significant impact in decreasing HCV viral loads within the first 7 days after transplantation. Trial Registration Number: The trial was registered at clinicaltrials.gov (NCT03112044). Funding Statement: This study was an investigator-initiated study funded by an operating grant from the Canadian Institutes of Health Research (CIHR). Gilead Sciences provided S/V (Epclusa) for all patients in the study. XVIVO perfusion (Gothenburg, Sweden) provided Steen solution for EVLP Declaration of Interests: Dr. Cypel, Waddell and Keshavjee are co-founders of Perfusix Canada, XOR Labs Toronto, and consultants for Lung Bioengineering (United Therapeutics). Ethics Approval Statement: This study was approved by the Research Ethics Board of University Health Network and subjects provided written informed consent while on the transplant waiting list prior to the offer of HCV+ve donor lungs.

MP29-17 HYDROGEN SULFIDE TREATMENT MITIGATES DONOR TISSUE NECROSIS DURING PROLONGED COLD STORAGE AND IMPROVES SURVIVAL FOLLOWING ALLOGENEIC RENAL TRANSPLANTATION.

You have accessJournal of UrologyTransplantation & Vascular Surgery: Renal Transplantation & Vascular Surgery I1 Apr 2016MP29-17 HYDROGEN SULFIDE TREATMENT MITIGATES DONOR TISSUE NECROSIS DURING PROLONGED COLD STORAGE AND IMPROVES SURVIVAL FOLLOWING ALLOGENEIC RENAL TRANSPLANTATION. Ian Lobb, Weihua Liu, Jifu Jiang, Dameng Lian, and Alp Sener Ian LobbIan Lobb More articles by this author , Weihua LiuWeihua Liu More articles by this author , Jifu JiangJifu Jiang More articles by this author , Dameng LianDameng Lian More articles by this author , and Alp SenerAlp Sener More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1101AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Organ procurement is inherently associated with ischemia-reperfusion injury (IRI), resulting from loss and subsequent restoration of blood flow, which is detrimental to short- and long-term graft function and survival. Treatment of donor organs with small molecules such as hydrogen sulfide (H2S) is a novel method of modulating prolonged IRI during transplantation. We postulated that H2S treatment during prolonged cold storage could mitigate IRI-induced renal allograft injury following allogeneic renal transplantation (RTx). METHODS Following bilateral native nephrectomy, recipient Lewis rats underwent RTx with kidneys obtained from Brown Norway donor rats that were flushed with either University of Wisconsin preservation solution (UW group; n=8) or UW + 150 µM NaHS (H2S group; n=5) and stored for 24 hours at 4°C in the same solution. Sham surgeries (midline incision only; n=5) were also performed and animals were monitored for 14 days to assess allograft function and survival. An additional subset of donor kidneys in each treatment group (n=8 per group) were perfused with 5 μM Ethidium Homodimer-1 (EthD-1) immediately following cold storage and analyzed via fluorescent microscopy for in situ characterization of tissue necrosis. ATP levels were also measured to assess the metabolic state of donor kidneys following cold storage. RESULTS H2S treated animals exhibited significantly improved (p<0.05) survival and markedly decreased serum creatinine compared to UW treatment alone. Donor kidneys supplemented with H2S exhibited significantly decreased (p<0.05) EthD-1 staining and markedly improved ATP levels compared to UW treated kidneys immediately following cold storage. CONCLUSIONS H2S treatment mitigates IRI associated with prolonged cold storage and acutely improves subsequent allograft function and survival. H2S appears to limit tissue necrosis and may maintain cellular metabolism during prolonged cold storage. H2S treatment could represent a novel and cost-effective method of protecting kidneys during transplantation and improving clinical transplant outcomes. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e386-e387 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Ian Lobb More articles by this author Weihua Liu More articles by this author Jifu Jiang More articles by this author Dameng Lian More articles by this author Alp Sener More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

720 Analysis of de novo urologic cancer in kidney transplant recipients: Single center study of 3,951 cases

from loss and subsequent restoration of blood flow, which is detrimental to shortand long-term graft function and survival. Treatment of donor organs with small molecules such as hydrogen sulfide (H2S) is a novel method of modulating prolonged IRI during transplantation. We postulated that H2S treatment during prolonged cold storage could mitigate IRI-induced renal allograft injury following allogeneic renal transplantation (RTx). METHODS: Following bilateral native nephrectomy, recipient Lewis rats underwent RTx with kidneys obtained from Brown Norway donor rats that were flushed with either University of Wisconsin preservation solution (UWgroup; n1⁄48) or UW+150 mMNaHS (H2Sgroup; n1⁄45) and stored for 24 hours at 4 C in the same solution. Sham surgeries (midline incision only; n1⁄45) were also performed and animals were monitored for 14 days to assess allograft function and survival. An additional subset of donor kidneys in each treatment group (n1⁄48 per group) were perfused with 5 mM Ethidium Homodimer-1 (EthD-1) immediately following cold storage and analyzed via fluorescent microscopy for in situ characterization of tissue necrosis. ATP levels were also measured to assess the metabolic state of donor kidneys following cold storage. RESULTS: H2S treated animals exhibited significantly improved (p<0.05) survival and markedly decreased serum creatinine compared to UW treatment alone. Donor kidneys supplemented with H2S exhibited significantly decreased (p<0.05) EthD-1 staining and markedly improved ATP levels compared to UW treated kidneys immediately following cold storage. CONCLUSIONS: H2S treatment mitigates IRI associated with prolonged cold storage and acutely improves subsequent allograft function and survival. H2S appears to limit tissue necrosis and may maintain cellular metabolism during prolonged cold storage. H2S treatment could represent a novel and cost-effective method of protecting kidneys during transplantation and improving clinical transplant outcomes.

P31 Hydrogen sulfide treatment improves graft function and survival following prolonged cold ischemia and allogeneic renal transplantation

Organ procurement is inherently associated with ischemia–reperfusion injury (IRI), resulting from loss and subsequent restoration of blood flow, and is detrimental to graft function and survival. Treatment of donor organs with small molecules such as hydrogen sulfide (H 2 S) may be a novel method of mitigating IRI during transplantation. We postulated that H 2 S treatment could mitigate IRI during cold organ storage and subsequent genetically mismatched (allogeneic) renal transplantation (RTx), improving allograft function and survival. Following bilateral native nephrectomy, recipient Lewis rats underwent RTx with kidneys obtained from Brown Norway donor rats that were flushed with either University of Wisconsin preservation solution (UW group) or UW + H 2 S (150 μM NaHS; H 2 S group) and stored for 24 h at 4°C in the same solution. Serum was obtained on subsequent post-operative (PO) days and creatinine was used as a surrogate marker of graft function. H 2 S treated animals exhibited significantly improved survival compared to UW animals ( p < 0.01), with UW animals exhibiting 0% survival by PO day 4 and H 2 S treated animals retaining 20% survival by PO day 14 (end of time course). As well, UW treated animals exhibited markedly increased serum creatinine levels at both PO days 2 and 4 compared to H 2 S animals. These findings indicate that H 2 S treatment can mitigate graft injury following prolonged periods of cold IRI, improving initial graft function and possibly delaying graft rejection. H 2 S treatment could represent a novel method of mitigating IRI during transplantation, thereby improving clinical outcomes.

P57 Hydrogen sulfide treatment reduces activation of ischemia–reperfusion injury-induced tissue inflammatory processes and resultant recipient adaptive immune response to donor tissue during allogeneic renal transplantation

Background Organ procurement is inherently associated with ischemia–reperfusion injury (IRI), resulting from loss and subsequent restoration of blood flow and is detrimental to short- and long-term graft function and survival. Treatment of donor organs with endogenously produced gasotransmitters such as hydrogen sulfide (H 2 S) is a novel method of mitigating IRI during transplantation, as previously shown in a model of murine syngeneic renal transplantation (RTx) [1] . The protective effects of H 2 S against IRI during allogeneic RTx, in which genetically dissimilar grafts are targeted by the recipient immune system causing organ rejection, have not yet been studied. Since H 2 S is known to exhibit anti-inflammatory actions during tissue IRI, we postulated that H 2 S treatment during allogeneic RTx could reduce graft inflammation and modulate the resultant recipient immune response against donor tissue. Methods Following bilateral native nephrectomy, recipient Lewis rats underwent RTx with left kidneys obtained from Brown Norway donor rats that were flushed, at the time of procurement, with either cold (4°C) University of Wisconsin standard preservation solution (UW group) or cold UW + H 2 S donor molecule (150 μ M NaHS) (H 2 S group) and stored for 6 h at 4°C in the same solution. Sham animals were also followed. Renal grafts were obtained at post-operative day 2 and RNA was isolated from renal homogenates for gene microarray analysis (Affymetrix Rat Gene 1.0 ST Microarray). Additionally, serum was collected post-operatively at day 1 to 2 and at time of sacrifice to determine the relative abundance of allo-reactive serum antibodies. TIB-120 cells (ATCC), a rat B-cell line heterozygous for Brown Norway and Lewis alleles, were incubated with serum from transplant recipients in each treatment group, stained for bound rat IgG/M antibodies and analyzed via flow cytometry. Results Upon microarray analysis both treatment groups exhibited significant enrichment in genes involved in inflammatory and innate immune responses as well as cytokine signaling and antigen processing at day 2 compared to Sham (p 2 S treated grafts had markedly reduced enrichment scores in each of these pro-inflammatory processes compared to UW. Upon allo-antibody binding analysis both UW and H 2 S treatment groups exhibited similar trends, with more cells unbound by allo-antibodies at day 1 to 2 and few unbound cells at time of sacrifice. However, while cells incubated with UW serum at day 1 to 2 exhibited markedly more allo-antibody binding (27% unbound cells) compared to cells incubated with naive Sham serum (37% unbound cells), cells incubated with H 2 S serum at day 1 to 2 exhibited similar levels of allo-antibody binding (40% cells unbound) as those incubated with Sham serum. These findings indicate that H 2 S treated animals experienced less acute graft inflammation, leading to a delayed induction of adaptive immune response to donor tissue compared to UW alone. Conclusions These findings are the first to report that H 2 S treatment may modulate the recipient immune response to donor tissue during allogeneic RTx. This phenomenon could represent an important underlying mechanism of H 2 S-mediated protection against renal injury early in the transplant curriculum, ultimately prolonging the survival and function renal allografts.

P1 Hydrogen sulfide improves renal graft function and survival in a model of allogeneic renal transplantation

Organ procurement is inherently associated with ischemia–reperfusion injury (IRI), resulting from loss and subsequent restoration of blood flow and leading to increased rates of delayed graft function, acute graft rejection and early graft loss. Additionally, genetically dissimilar grafts are targeted by the recipient immune system causing rejection of the donor organ. Treatment of donor organs with endogenously produced gasotransmitters such as hydrogen sulfide (H 2 S) during preservation is a novel method for improving early graft function and survival, as has been previously illustrated in a model of murine syngeneic renal transplantation (RTx). The protective effects of H 2 S against IRI in renal allografts have not yet been studied. We aimed to characterize the protective role of H 2 S in a clinically applicable murine model of allogeneic RTx involving immunosuppressive therapy. Following bilateral native nephrectomy, recipient Lewis rats underwent RTx with left kidneys obtained from Brown Norway donor rats that were flushed, at the time of procurement, with 15 mL of either cold (4 °C) University of Wisconsin (UW group) or cold UW + H 2 S donor molecule (150 μM NaHS) (H 2 S group) solution and stored for 6 h at 4 °C in 50 mL of the same solution. Rats were monitored for 14 days or until time of sacrifice. Post-operatively, a subset of animals from the UW group were treated with the immunosuppressant Tacrolimus (Prograf®, 0.3 mg/kg; UW + TAC) daily. Blood was analyzed periodically for serum creatinine and blood urea nitrogen (BUN) concentrations as markers of kidney function, as well as serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentration as markers of systemic inflammation. Post-operative survival of rats was markedly improved in H 2 S treated animals compared to animals treated with UW alone ( Fig. 1 ). Treatment with tacrolimus further enhanced survival, with UW + TAC and H 2 S + TAC exhibiting 50% and 100% survival, respectively, at day 14. Whereas UW treated animals exhibited high serum creatinine and BUN levels that remained elevated until time of death, H 2 S treated animals initially exhibited reduced serum creatinine and BUN levels compared to UW that gradually increased until death later in the time course ( Fig. 2 ). H 2 S + TAC treatment and UW + TAC groups both showed a reduction in serum creatinine and BUN to normal levels by day 7, though this reduction occurred sooner in the H 2 S + TAC group. Serum levels of ALT and AST were initially elevated in all treatment groups. However, whereas these levels were decreased in both tacrolimus treated groups by day 4 until the end of the time course, H 2 S treated animals exhibited a surge of serum ALT and AST near the time of death (day 8.5). These findings are the first to report that H 2 S protects kidney allograft survival and function. H 2 S treatment appears to delay the onset of graft rejection associated with allogeneic transplantation, most likely mediated by anti-inflammatory actions of H 2 S. Further investigation into the effect of H 2 S on the innate and adaptive immune system may elucidate potential mechanisms behind these protective effects.

Hydrogen-Enriched Preservation Protects the Isogeneic Intestinal Graft and Amends Recipient Gastric Function During Transplantation

Inhaled hydrogen gas exerts antioxidant and anti-inflammatory effects in rat intestinal transplantation. Here, we investigated whether ex vivo donor organ treatment with dissolved hydrogen would prevent intestinal graft injury. Isogeneic intestinal transplantation was performed in Lewis rats with vascular flush, luminal preservation, and cold graft storage in nitrogen-bubbled (SITxN2) or hydrogen-bubbled (SITxH2) preservation solution. Lactated Ringer's solution and 3-hr cold ischemia time were used for mechanistic investigations, whereas survival experiments were performed with University of Wisconsin solution and 6-hr cold ischemia time. During the early phase of ischemia-reperfusion injury, hydrogen-enriched solution significantly preserved mucosal graft morphology, diminished graft malondialdehyde levels demonstrating substantial reduction potential and blunted proinflammatory molecular responses (early growth response gene [EGR-1], interleukin [IL]-6, IL-1ß, and inducible nitric oxide synthase) within the reperfused intestinal graft muscularis. During the late phase of ischemia-reperfusion injury, circulating IL-6 protein and lactate dehydrogenase levels were significantly ameliorated in SITxH2 animals, which were associated with a favorable functional outcome in in vivo liquid gastrointestinal transit and recipient solid gastric emptying of chrome steel balls, and marked prevention of the posttransplant associated suppression of in vitro muscarinic jejunal contractility. Reflecting improved graft preservation, hydrogen preloading of grafts increased recipient survival rates from 41% to 80%. Anti-inflammatory and antiapoptotic heme oxygenase-1 was significantly upregulated in the hydrogen-treated graft muscularis but not mucosa before reperfusion. Graft preloading with hydrogen demonstrated superior morphologic and functional graft protection in rodent intestinal transplantation, ultimately facilitating recipient survival. Antioxidant capacity and muscularis heme oxygenase-1 upregulation are possible protective mechanisms.

RHuEPo Reduces Ischemia-Reperfusion Injury and Improves Survival After Transplantation of Fatty Livers in Rats

The scarcity of appropriate donor organs remains to be a major problem in transplantation surgery today. This has led to increased acceptance of so-called marginal grafts, incorporating the increased risk of poor posttransplant function. Erythropoietin has been shown to reduce ischemia-reperfusion injury in transplanted rat livers. We investigated whether these capacities may contribute to improve marginal organ function. One hundred and forty Lewis rats were used. Fatty liver (>or=50% steatosis) was induced by a special diet in 70 donor animals. Seventy recipients received liver transplantation after donor organ treatment with 1000 IU rhuEpo or saline injection (controls) into portal veins (cold ischemia 6 hr, University of Wisconsin solution). Recipients were allocated to two groups which received 1000 IU rHuEpo at reperfusion or an equal amount of saline (control). Analysis of liver enzymes, histology (hematoxylin-eosin and periodic acid Schiff stain), immunostaining (terminal deoxynucleotide transferase- mediated dUTP nick-end labeling, hypoxyprobe, and tumor necrosis factor-alpha), and reverse transcriptase-polymerase chain reaction of cytokine messenger RNA (interleukin-1, interleukin-6, hypoxia induced factor-1 alpha, vascular endothelial growth factor, and hepatocyte growth factor) were performed at defined time points (2, 4.5, 24, 48 hr, and 7 days postoperatively). Alanine aminotransferase values were significantly reduced for epo-treated rats 48 hr after reperfusion; however, at all other time points enzyme levels were without significant differences. Terminal deoxynucleotide transferase-mediated dUTP nick-end labeling and hypoxyprobe analysis and necrotic index evaluation displayed significant reduction of apoptosis and hypoxic cells in rHuEpo-treated graft livers. Overall survival was significantly improved among epo-treated rats. Erythropoietin improves marginal graft function and recipient survival after transplantation of fatty livers in rats.

Erythropoietin reduces ischemia-reperfusion injury after liver transplantation in rats

Human recombinant Erythropoietin (rHuEpo) has recently been shown to be a potent protector of ischemia- reperfusion injury in warm-liver ischemia. Significant enhancement of hepatic regeneration and survival after large volume partial hepatic resection has also been demonstrated. It was the aim of this study to evaluate the capacities of rHuEpo in the setting of rat liver transplantation. One-hundred-and-twenty Wistar rats were used: 60 recipients received liver transplantation following donor organ treatment (60 donors) with either 1000 IU rHuEpo or saline injection (controls) into portal veins (cold ischemia 18 h, University of Wisconsin (UW) solution). Recipients were allocated to two groups, which either received 1000 IU rHuEpo at reperfusion or an equal amount of saline (control). Animals were sacrificed at defined time-points (2, 4.5, 24, 48 h and 7 days postoperatively) for analysis of liver enzymes, histology [hematoxylin-eosin (HE) staining, periodic acid Schiff staining (PAS)], immunostaining [terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Hypoxyprobe] and real-time polymerase chain reaction (RT-PCR) of cytokine mRNA (IL-1, IL-6). Lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) values were significantly reduced among the epo-treated animals 24 and 48 h after liver transplantation (LT). The TUNEL and Hypoxyprobe analyses as well as necrotic index evaluation displayed significant reduction of apoptosis and necrosis in rHuEpo-treated graft livers. Erythropoietin reduces ischemia-reperfusion injury after orthotopic liver transplantation in rats.

Wound Healing in the Biliary Tree of Liver Allografts

An increasing need for liver transplantation requires evaluation and triage of organs harvested from "extended criteria" donors. Although there is currently no widely accepted definition, most would agree that "extended criteria" includes organs donated by individuals that are old (>65 years), obese, infected with HBV or HCV, non-heart beating (NHBD), or had an unstable blood pressure before harvesting or the organ experienced a long cold ischemic time. These organs carry a statistical risk of dysfunction early after transplantation, but in the majority of recipients, hepatic parenchymal function recovers. Later, however, a small but significant percentage of extended criteria donors develop biliary strictures within several months after transplantation. The strictures occur primarily because of preservation injury that leads to "ischemic cholangitis" or deep wounding of the bile duct wall. Subsequent partial wound healing and wound contraction, but failed restitution of the biliary epithelial cell (BEC) lining, result in biliary tract strictures that cause progressive biliary fibrosis, increased morbidity, and decreased organ half-life. Better understanding of the pathophysiologic mechanisms that lead to biliary strictures in extended criteria donors provides an ideal proving ground for regenerative medicine; it also can provide insights into other diseases, such as extrahepatic biliary atresia and primary sclerosing cholangitis, that likely share certain pathogenic mechanisms. Possible points of therapeutic intervention include limiting cold and warm ischemic times, donor and/or donor organ treatment, ex vivo, to minimize the ischemic/preservation injury, maximize blood flow after transplantation, promote BEC wound healing, and limit myofibroblasts activation and proliferation in the bile duct wall. The pathobiology of biliary wound healing and therapeutic potential of interleukin-6 (IL-6) are highlighted.

Nontransgenic Hyperexpression of a Complement Regulator in Donor Kidney Modulates Transplant Ischemia/Reperfusion Damage, Acute Rejection, and Chronic Nephropathy

Complement activation during ischemia and reperfusion contributes to the development of tissue injury with severe negative impact on outcomes in transplantation. To counter the effect of complement, we present a strategy to deliver a novel complement regulator stabilized on cell surfaces within donor organs. The membrane-bound complement regulator is able to inhibit complement activation when the donor organ is revascularized and exposed to host-circulating complement. Application of this construct to donor kidneys protected transplanted tissues from ischemia/reperfusion injury and reduced the deposition of activated complement and histological signs of damage under conditions in which a nontargeted control construct was ineffective. Treatment of donor organs in this way improved graft performance in the short and long term. An analysis of the immune response in allograft recipients showed that reducing graft damage at the time of transplantation through complement regulation also modulated the alloresponse. Additionally, the results of perfusion studies with human kidneys demonstrated the feasibility of targeting endothelial and epithelial surfaces with this construct, to allow investigation in clinical transplantation.

Selective transplantation. An emerging concept.

The purpose of this paper is to call attention to a number of approaches that have recently become attractive for the treatment of donor organs or tissues prior to transplantation in such a way that they succeed better as transplants thereafter. These treatments are designed to select from an organ or tissue those cellular elements required for the express purposes of the transplant. Three sets of examples of "selective transplantation" are offered; those that focus upon the maintenance of mechanical functions of the donor tissue, those in which metabolic properties of the graft are paramount, and those in which immunological considerations are primary. Although it is predicted that the selective approach described will prove to be useful in a variety of clinical settings, the full extent of its applicability remains to be demonstrated.