Intrahepatic biliary strictures after liver transplantation

Extrahepatic Bile Duct Organoids as a Model to Study Ischemia/Reperfusion Injury During Liver Transplantation

Biliary complications are still a major cause for morbidity and mortality after liver transplantation (LT). Ischemia/reperfusion injury (IRI) leads to disruption of the biliary epithelium. We introduce a novel model to study the effect of IRI on human cholangiocytes using extrahepatic cholangiocyte organoids (ECOs). Extrahepatic bile duct tissue was collected during LT at static cold storage and after reperfusion (n = 15); gallbladder tissue was used for controls (n = 5). ECOs (n = 9) were cultured from extrahepatic biliary tissue, with IRI induced in an atmosphere of 95% air (nitrogen), 1% O2 and 5% CO2for 48 h, followed by 24 h of reoxygenation. Qualitative and quantitative histology and qRT-PCR were performed to discern phenotype, markers of hypoxia, programmed cell death and proliferation. ECOs self-organized into circular structures resembling biliary architecture containing cholangiocytes that expressed EpCAM, CK19, LGR5 and SOX-9. After hypoxia, ECOs showed increased expression of VEGF A (p < 0.0001), SLC2A1 (p < 0.0001) and ACSL4 (p < 0.0001) to indicate response to hypoxic damage and subsequent programmed cell death. Increase in cyclin D1 (p < 0.0001) after reoxygenation indicated proliferative activity in ECOs. Therefore, ECO structure and response to IRI are comparable to that found in-vivo, providing a suitable model to study IRI of the bile duct in-vitro.

A case of hepaticojejunal anastomotic obstruction after a living-donor liver transplantation and recanalization using a high-frequency knife under the rendezvous technique

A 65-year-old woman underwent living-donor liver transplantation (left-lobe graft: GWRW ratio, 0.54) for cirrhosis caused by autoimmune hepatitis. At 68 years, she was diagnosed with obstructive cholangitis due to stricture during a hepaticojejunostomy following impaired liver function. Endoscopic balloon dilation of anastomosis and placement of a plastic stent resulted in improved liver function. However, at 72 years, the patient experienced a flare-up of liver damage. The plastic stent had fallen out, and although endoscopic stenotic dilation was attempted, the anastomotic site was obstructed completely. Therefore, recanalization of the hepaticojejunostomy was attempted using a rendezvous technique. A percutaneous transhepatic biliary drainage tube was inserted through the B3 bile duct, and the complete obstructed anastomosis was confirmed by percutaneous transhepatic and transjejunal approaches. The anastomosis was reopened by excising the scarred tissues from the jejunal side using a 1.5-mm high-frequency knife. A 14-Fr. catheter for the internal fistula tube was percutaneously placed at the opened anastomosis to achieve anastomotic site recanalization. The patient's liver damage improved after the re-internalization, and no symptom recurrence such as obstructive cholangitis developed for 1 year. There are few reports of recanalization of the hepaticojejunostomy with a high-frequency knife. Herein, we report the case with a literature review.

Early γGT and bilirubin levels as biomarkers for regeneration and outcomes in damaged bile ducts after liver transplantation

BACKGROUND

Early patient and allograft survival after liver transplantation (LT) depend primarily on parenchymal function, but long-term allograft success relies often on biliary-tree function. We examined parameters related to cholangiocyte damage that predict poor long-term LT outcomes after donation after brain death (DBD).

METHODS

Sixty bile ducts (BD) were assessed by a BD damage-score and divided into groups with "major" BD-damage (n = 33) and "no relevant" damage (n = 27) during static cold storage. Patients with "major" BD damage were further investigated by measuring biliary excretion parameters in the first 14 days post-LT (followed-up for 60-months).

RESULTS

Patients who received LT showing "major" BD damage had significantly worse long-term patient survival, versus grafts with "no relevant" damage (p = .03). When "major" BD damage developed, low bilirubin levels (p = .012) and high gamma-glutamyl transferase (GGT)/bilirubin ratio (p = .0003) were evident in the early post-LT phase (7-14 days) in patients who survived (> 60 months), compared to those who did not. "High risk" patients with bile duct damage and low GGT/bilirubin ratio had significantly shorter overall survival (p < .0001).

CONCLUSIONS

Once "major" BD damage occurs, a high GGT/bilirubin ratio in the early post-operative phase is likely indicator of liver and cholangiocyte regeneration, and thus a harbinger of good overall outcomes. "Major" BD damage without markers of regeneration identifies LT patients that could benefit from future repair therapies.

Safety and Efficacy of Living Donor Hepatectomy Without Systemic Heparinization: Short- and Long-Term Outcomes

There is no consensus regarding the use of systemic heparin, and long-term outcomes of living donor hepatectomy (LDH) without systemic heparinization have not yet been determined. This study was performed to determine whether systemic heparinization can be omitted during LDH, with a focus on donor safety and long-term outcomes. We retrospectively analyzed the outcomes of 175 cases of LDH performed in our institution between January 2011 and December 2014: group I (n = 79) received systemic heparinization, whereas group II (n = 96) did not, but liver graft was flushed with a heparinized perfusate. Postoperative bleeding requiring blood transfusion or intervention was more frequent in group I than in group II (P = .028). The decreases in donor hemoglobin and hematocrit levels, and platelet count during the early postoperative period, were greater in group I than in group II. In multivariate analysis, systemic heparin was the only independent risk factor for blood transfusion (odds ratio [OR] = 5.114; 95% confidence interval [CI]: 1.201-21.775; P = .027) and significant postoperative bleeding (OR = 7.731; 95% CI: 1.345-44.429; P = .022) after LDH. Most postoperative complications including graft vascular thrombosis were similar between the 2 groups, as was the survival rate, and neither graft loss due to vascular thrombosis nor non-anastomotic biliary stricture was evident. In conclusion, omission of systemic heparinization during LDH is a feasible and safe option without adverse effects.

Liver Preservation by Aortic Perfusion Alone Compared With Preservation by Aortic Perfusion and Additional Arterial Ex Situ Back-Table Perfusion With Histidine-Tryptophan-Ketoglutarate Solution: A Prospective, Randomized, Controlled, Multicenter Study

Background

Arterial ex situ back-table perfusion (BP) reportedly reduces ischemic-type biliary lesion after liver transplantation. We aimed to verify these findings in a prospective investigation.

Methods

Our prospective, randomized, controlled, multicenter study involved livers retrieved from patients in 2 German regions, and compared the outcomes of standard aortic perfusion to those of aortic perfusion combined with arterial ex situ BP. The primary endpoint was the incidence of ischemic-type biliary lesions over a follow-up of 2 years after liver transplantation, whereas secondary endpoints included 2-year graft survival, initial graft damage as reflected by transaminase levels, and functional biliary parameters at 6 months after transplantation.

Results

A total of 75 livers preserved via standard aortic perfusion and 75 preserved via standard aortic perfusion plus arterial BP were treated using a standardized protocol. The incidence of clinically apparent biliary lesions after liver transplantation (n = 9 for both groups; P = 0.947), the 2-year graft survival rate (standard aortic perfusion, 74%; standard aortic perfusion plus arterial BP, 68%; P = 0.34), and incidence of initial graft injury did not differ between the 2 perfusion modes. Although 33 of the 77 patients with cholangiography workups exhibited injured bile ducts, only 10 had clinical symptoms.

Conclusions

Contrary to previous findings, the present study indicated that additional ex situ BP did not prevent ischemic-type biliary lesions or ischemia-reperfusion injury after liver transplantation. Moreover, there was considerable discrepancy between cholangiography findings regarding bile duct changes and clinically apparent cholangiopathy after transplantation, which should be considered when assessing ischemic-type biliary lesions.

Liver ex situ machine perfusion preservation: A review of the methodology and results of large animal studies and clinical trials

Ex vivo machine perfusion (MP) is a promising way to better preserve livers prior to transplantation. Currently, no methodology has a verified benefit over simple cold storage. Before becoming clinically feasible, MP requires validation in models that reliably predict human performance. Such a model has been found in porcine liver, whose physiological, anatomical, and immunological characteristics closely resemble the human liver. Since the 1930s, researchers have explored MP as preservation, but only recently have clinical trials been performed. Making this technology clinically available holds the promise of expanding the donor pool through more effective preservation of extended criteria donor (ECD) livers. MP promises to decrease delayed graft function, primary nonfunction, and biliary strictures, which are all common failure modes of transplanted ECD livers. Although hypothermic machine perfusion (HMP) has become the standard for kidney ex vivo preservation, the precise settings and clinical role for liver MP have not yet been established. In research, there are 2 schools of thought: normothermic machine perfusion, closely mimicking physiologic conditions, and HMP, to maximize preservation. Here, we review the literature for porcine ex vivo MP, with an aim to summarize perfusion settings and outcomes pertinent to the clinical establishment of MP. Liver Transplantation 23 679-695 2017 AASLD.

Endoscopic approach for management of biliary strictures in liver transplant recipients: A systematic review and meta-analysis

The most common biliary complication after liver transplantation is anastomotic stricture (AS) and it can occur isolated or in combination with other complications. Liver graft from a cadaveric donor or a living donor has an influence on the incidence of biliary strictures as well as on the response to endoscopic treatment. Endoscopic treatment using balloon dilation and insertion of biliary stents by endoscopic retrograde cholangiopancreatography (ERCP) is the initial approach to these complications.

AIM

The aim of this article is to compare different endoscopic techniques to treat post-liver transplantation biliary strictures.

METHODS

The search was carried out on MEDLINE, EMBASE, Scielo-LILACS and Cochrane Library databases through June 2015. A total of 1100 articles were retrieved. Ten clinical trials were analyzed, and seven were included in the meta-analysis.

CONCLUSIONS

The endoscopic treatment of AS was equally effective when compared the use of fully covered self-expandable metal stents (FCSEMS) vs. plastic stents, but the use of FCSEMS was associated with a lower complication risk. The treatment of AS with balloon dilation or balloon dilation associated with plastic stents presented similar results. Deceased donor liver transplantation reduced the risk of biliary stenosis and the endoscopic treatment in these patients was more effective when compared with Living donor liver transplantation.

ABO-Incompatible Living Donor Liver Transplantation in Focus of Antibody Rebound

BACKGROUND

Living donor liver transplantation (LDLT) is an option to expand the donor organ pool for patients with life-threatening diseases who cannot be supplied with a cadaver organ. Next to the donor risks, complications after ABO-incompatible LDLT (ABOi LDLT) in the recipient are subject to controversial discussion. Improvement in ABOi graft survival rates have been achieved with plasma treatment procedures (PTP) and immunosuppression but antibody-mediated rejection (AMR) and graft loss still occur.

METHODS

Since 2008, we have prepared 10 patients for ABOi LDLT. Seven of the 10 patients for transplantation had hepatocellular carcinoma (HCC).

RESULTS

All patients underwent PTP before and after ABOi LDLT as well as immunosuppression according to the treatment schedule. We did not use anti-CD20 monoclonal antibodies in the transplant setting. We transplanted 6 of 10 preconditioned patients. After 3 years, 5 of the 6 transplanted patients were still alive.

CONCLUSION

Even if B-cell depletion with anti-CD 20 treatment in the setting of ABOi LDLT is commonly accepted, our center successfully administered only quadruple drug immunosuppression combined with PTP. Especially patients with HCC had a high titer increment also pre-transplantation and were at high risk for arterial thrombosis and graft loss.

Current techniques for AB0-incompatible living donor liver transplantation

For a long time, it was considered medical malpractice to neglect the blood group system during transplantation. Because there are far more patients waiting for organs than organs available, a variety of attempts have been made to transplant AB0-incompatible (AB0i) grafts. Improvements in AB0i graft survival rates have been achieved with immunosuppression regimens and plasma treatment procedures. Nevertheless, some grafts are rejected early after AB0i living donor liver transplantation (LDLT) due to antibody mediated rejection or later biliary complications that affect the quality of life. Therefore, the AB0i LDLT is an option only for emergency situations, and it requires careful planning. This review compares the treatment possibilities and their effect on the patients’ graft outcome from 2010 to the present. We compared 11 transplant center regimens and their outcomes. The best improvement, next to plasma treatment procedures, has been reached with the prophylactic use of rituximab more than one week before AB0i LDLT. Unfortunately, no standardized treatment protocols are available. Each center treats its patients with its own scheme. Nevertheless, the transplant results are homogeneous. Due to refined treatment strategies, AB0i LDLT is a feasible option today and almost free of severe complications.

Risk factors for and management of ischemic-type biliary lesions following orthotopic liver transplantation: A single center experience

INTRODUCTION

Biliary complications can cause morbidity, graft loss, and mortality after liver transplantation. The most troublesome biliary complications are ischemic-type biliary lesions (ITBL), which occur since transplants can now be performed after the donor has undergone circulatory death. The exact origin of this type of biliary complication remains unknown.

MATERIAL AND METHODS

A total of 528 patients were retrospectively analyzed following liver transplantation after excluding 30 patients with primary sclerosing cholangitis and those lost to follow-up from January 2007 to January 2014. The incidence of and risk factors for ITBL were evaluated.

RESULTS

Cold ischemia time (CIT) (P = 0.042) and warm ischemia time (WIT) (P = 0.006) were found to be independent risk factors for the development of ITBL. Use of the cytochrome P450 (CYP) 3A5 genotype assay to guide individualization of immunosuppressive medications resulted in significantly fewer ITBL (P = 0.027. Autoimmune hepatitis might be a risk factor for ITBL, as determined using univariate analysis (P = 0.047).

CONCLUSIONS

Efforts should be taken to minimize risk factors associated with ITBL, such as CIT and WIT. The CYP3A5 genotype assay should be used to guide selection of immunosuppressive therapy in an effort to reduce the occurrence of ITBL.

Liver Transplantation Using Donation After Brain and Cardiac Death: A Single-Center Experience in China

BACKGROUND

Liver transplantation (LTx) using donation after brain and cardiac death (DBCD) has increased steadily in China. The aims of this study were to evaluate the outcomes of DBCD LTx and to assess its feasibility to expand the donor pool.

METHODS

We retrospectively analyzed the clinical characteristics of DBCD donors and recipients, survival of allografts and recipients, and prognostic factors in DBCD LTx recipients from March 2010 to December 2014 in our institution.

RESULTS

DBCD LTx (n = 102) were performed in our institution during the research period, and the successful donation rate was 26.0%. Mean warm ischemia time and cold ischemia time were 14.39 minutes and 5.29 hours, respectively. The overall and biliary complication rates were 45.1% and 16.7%, respectively. Donor age (P = .043), intra-operative blood loss (P = .048), and operation time (P = .045) were significantly different between the complication and non-complication groups. The 1-, 2-, and 3-year survival rates of patients and grafts were 88.0%, 84.6%, 84.6%, and 85.7%, 78.6%, and 78.6%, respectively. The 1- and 2-year overall survival rates of hepatocellular carcinoma patients were 91.9% and 80.5%, respectively whereas the recurrence-free survival rates were 84.9% and 77.2%, respectively. The patient and graft survival rates were not statistically different between the <55-year and ≥55 year groups, but complication rate was higher in the older group than in the younger group (P = .003).

CONCLUSIONS

The outcome of DBCD LTx is favorable in our institution, with careful donor and recipient selection and careful peri-operative management. DBCD is an optimized solution for organ shortage in today's China.

ABO-incompatible liver transplantation for severe hepatitis B patients

Effect of ABO-incompatible liver transplantation on patients with severe hepatitis B (SHB) remains unclear. Herein, we summarized 22 cases with SHB in whom were performed emergency liver transplantation from ABO-incompatible donors. The immunosuppressive protocol consisted basiliximab, tacrolimus, steroids and mycophenolate mofetil. The mean MELD score was 35.2 ± 7.1. Major complications included rejection, infections, biliary complications, hepatic artery thrombosis or stenosis and portal vein thrombosis. Patient survival rates were 40.9%, 78.9% and 82.3% in 1 year, 29.2%, 66.8% and 72.9% in 3 years, and 21.9%, 60.1% and 62.5% in 5 years for ABO-incompatible, ABO-compatible and ABO-identical groups. Graft survival rates were 39%, 78.9% and 82.3% in 1 year, 27.8%, 66.4% and 71.1% in 3 years, and 20.9%, 57.9% and 61.0% in 5 years for incompatible, compatible and identical ABO graft-recipient match. The 1-, 3-, 5-year graft and patient survival rates of ABO-incompatible were distinctly lower than that of ABO-compatible group (P < 0.05). Our results suggested that ABO-incompatible liver transplantation might be a life-saving procedure for patients with SHB as a promising alternative operation when ABO-compatible donors are not available and at least bridges the second opportunity for liver retransplantation.

Outcome of duct-to-duct vs. Roux-en-Y hepaticojejunostomy biliary anastomoses in below 15-kg pediatric liver transplant recipients

The best type of biliary anastomosis to use in lower weight pediatric liver transplant recipients is debatable. In this study, we share a single center's experience comparing the rate of anastomotic biliary complications based on the type of biliary anastomosis performed in this population of patients. A retrospective review of pediatric liver transplants for recipients weighing <15 kg from 11/2003 till 12/2011 was performed. Patients were grouped based on the type of biliary anastomosis into two groups: duct-to-duct (d-d) and Roux-en-Y hepaticojejunostomy (h-j) anastomoses. A total of 24 patients (12 males, 12 females) with a mean age of 26 ± 20 months and a mean weight of 9.27 ± 2.63 kg (range = 5.3-13.9 kg) were studied. All anastomotic complications occurred in patients who received left lateral segments. No statistical differences were found in the post-operative biliary (p = 0.86) or vascular (p = 0.99) complications between the two groups. Acknowledging the limited sample size, our data suggest that duct-to-duct anastomosis can be performed safely in pediatric liver transplantation recipients weighing below 15 kg.

Aetiology and risk factors of ischaemic cholangiopathy after liver transplantation

Liver transplantation (LT) is the best treatment for end-stage hepatic failure, with an excellent survival rates over the last decade. Biliary complications after LT pose a major challenge especially with the increasing number of procured organs after circulatory death. Ischaemic cholangiopathy (IC) is a set of disorders characterized by multiple diffuse strictures affecting the graft biliary system in the absence of hepatic artery thrombosis or stenosis. It commonly presents with cholestasis and cholangitis resulting in higher readmission rates, longer length of stay, repeated therapeutic interventions, and eventually re-transplantation with consequent effects on the patient’s quality of life and increased health care costs. The pathogenesis of IC is unclear and exhibits a higher prevalence with prolonged ischaemia time, donation after circulatory death (DCD), rejection, and cytomegalovirus infection. The majority of IC occurs within 12 mo after LT. Prolonged warm ischaemic times predispose to a profound injury with a subsequently higher prevalence of IC. Biliary complications and IC rates are between 16% and 29% in DCD grafts compared to between 3% and 17% in donation after brain death (DBD) grafts. The majority of ischaemic biliary lesions occur within 30 d in DCD compared to 90 d in DBD grafts following transplantation. However, there are many other risk factors for IC that should be considered. The benefits of DCD in expanding the donor pool are hindered by the higher incidence of IC with increased rates of re-transplantation. Careful donor selection and procurement might help to optimize the utilization of DCD grafts.

Hypothermic oxygenated machine perfusion prevents arteriolonecrosis of the peribiliary plexus in pig livers donated after circulatory death

Background

Livers derived from donation after circulatory death (DCD) are increasingly accepted for transplantation. However, DCD livers suffer additional donor warm ischemia, leading to biliary injury and more biliary complications after transplantation. It is unknown whether oxygenated machine perfusion results in better preservation of biliary epithelium and the peribiliary vasculature. We compared oxygenated hypothermic machine perfusion (HMP) with static cold storage (SCS) in a porcine DCD model.

Methods

After 30 min of cardiac arrest, livers were perfused in situ with HTK solution (4°C) and preserved for 4 h by either SCS (n = 9) or oxygenated HMP (10°C; n = 9), using pressure-controlled arterial and portal venous perfusion. To simulate transplantation, livers were reperfused ex vivo at 37°C with oxygenated autologous blood. Bile duct injury and function were determined by biochemical and molecular markers, and a systematic histological scoring system.

Results

After reperfusion, arterial flow was higher in the HMP group, compared to SCS (251±28 vs 166±28 mL/min, respectively, after 1 hour of reperfusion; p = 0.003). Release of hepatocellular enzymes was significantly higher in the SCS group. Markers of biliary epithelial injury (biliary LDH, gamma-GT) and function (biliary pH and bicarbonate, and biliary transporter expression) were similar in the two groups. However, histology of bile ducts revealed significantly less arteriolonecrosis of the peribiliary vascular plexus in HMP preserved livers (>50% arteriolonecrosis was observed in 7 bile ducts of the SCS preserved livers versus only 1 bile duct of the HMP preserved livers; p = 0.024).

Conclusions

Oxygenated HMP prevents arteriolonecrosis of the peribiliary vascular plexus of the bile ducts of DCD pig livers and results in higher arterial flow after reperfusion. Together this may contribute to better perfusion of the bile ducts, providing a potential advantage in the post-ischemic recovery of bile ducts.

The influence of a contemporaneous portal and hepatic artery revascularization protocol on biliary complications after liver transplantation

BACKGROUND

We sought to compare the impact of sequential and contemporaneous revascularizations of portal vein and hepatic artery on biliary complications in patients undergoing liver transplantation.

METHODS

We reviewed 184 patients who underwent liver transplantation in our center, and categorized them into different groups based on the duration of time between the portal venous and hepatic arterial reperfusion: >10 minutes in the sequential portal and hepatic artery revascularization group (SPA; n = 56), and within 1 minute in the contemporaneous portal and hepatic artery revascularization group (CPA; n = 121).The other patients with an interval from 1-10 minutes (n = 7) were excluded. This study then compared the outcomes between the SPA and CPA groups.

RESULTS

Cold ischemic time (mean ± standard deviation) for the SPA and CPA groups were 561 ± 150 vs 577 ± 187 minutes, respectively (P = .53). The incidence of biliary complications for the SPA and CPA groups were 14/56 and 11/121, respectively (25% vs 9%; P = .005). By the Clavien-Dindo Classification of Surgical Complications, the biliary complications in SPA group tended to be more severe compared with the CPA group (grade I, 0% vs 0%; II, 14% vs 36%; IIIa, 71% vs 64%; IIIb, 7% vs 0%; IV, 7% vs 0%; P = .10). Among biliary complications, the incidence of nonanatomic strictures was greater in the SPA group (9% vs 2%; P = .03), whereas the difference was not significant for anastomotic strictures (P = .054). Except for a lower serum albumin level in the SPA group 1 day after liver transplantation (P < .001), there are no differences in post-transplant liver function or renal function at 1, 7, and 30 days after transplantation.

CONCLUSION

The CPA protocol can decrease the incidence of biliary complications substantially after liver transplantation and should replace the SPA protocol used by some centers in liver transplantation.

Chemokines in chronic liver allograft dysfunction pathogenesis and potential therapeutic targets

Despite advances in immunosuppressive drugs, long-term success of liver transplantation is still limited by the development of chronic liver allograft dysfunction. Although the exact pathogenesis of chronic liver allograft dysfunction remains to be established, there is strong evidence that chemokines are involved in organ damage induced by inflammatory and immune responses after liver surgery. Chemokines are a group of low-molecular-weight molecules whose function includes angiogenesis, haematopoiesis, mitogenesis, organ fibrogenesis, tumour growth and metastasis, and participating in the development of the immune system and in inflammatory and immune responses. The purpose of this review is to collect all the research that has been done so far concerning chemokines and the pathogenesis of chronic liver allograft dysfunction and helpfully, to pave the way for designing therapeutic strategies and pharmaceutical agents to ameliorate chronic allograft dysfunction after liver transplantation.

ABO-incompatible liver transplantation in acute liver failure: a single Portuguese center study

INTRODUCTION

ABO-incompatible liver transplantation (ABOi LT) is considered to be a rescue option in emergency transplantation. Herein, we have reported our experience with ABOi LT including long-term survival and major complications in these situations.

PATIENT AND METHODS

ABOi LT was performed in cases of severe hepatic failure with imminent death. The standard immunosuppression consisted of basiliximab, corticosteroids, tacrolimus, and mycophenolate mofetil. Pretransplantation patients with anti-ABO titers above 16 underwent plasmapheresis. If the titer was above 128, intravenous immunoglobulin (IVIG) was added at the end of plasmapheresis. The therapeutic approach was based on the clinical situation, hepatic function, and titer evolution. A rapid increase in titer required five consecutive plasmapheresis sessions followed by administration of IVIG, and at the end of the fifth session, rituximab.

RESULTS

From January 2009 to July 2012, 10 patients, including 4 men and 6 women of mean age 47.8 years (range, 29 to 64 years), underwent ABOi LT. At a mean follow-up of 19.6 months (range, 2 days to 39 months), 5 patients are alive including 4 with their original grafts. One patient was retransplanted at 9 months. Major complications were infections, which were responsible for 3 deaths due to multiorgan septic failure (2 during the first month); rejection episodes (4 biopsy-proven of humoral rejections in 3 patients and 1 cellular rejection) and biliary.

CONCLUSION

The use of ABOi LT as a life-saving procedure is justifiable in emergencies when no other donor is available. With careful recipient selection close monitoring of hemagglutinins and specific immunosuppression we have obtained acceptable outcomes.

Rewarming Machine Perfusion System for Liver Transplantation

The liver is one of the most essential organs, and transplantation is an established treatment for patients with end-stage disease who have lost their liver function. However, organ shortage is a critical problem in transplantation; thus, the development of an innovative preservation system to adopt critical grafts obtained from extended criteria donors or donation after cardiac death donors as viable organs for transplantation is necessary. We recently developed a novel rewarming machine perfusion preservation system for liver transplantation, and herein discuss this system, which allows the perfusion temperature to be controlled during the transition from hypothermic to subnormothermic conditions. This system has two functions: (1) the preservation and recovery of organ function and (2) screening the organ for viability. To achieve these functions, this system has three features: (1) temperature control of the preservation perfusate and liver graft, (2) dual-controlled perfusion of the portal vein and hepatic artery, and (3) real-time monitoring of the perfusion conditions, including the flow rate, perfusion pressure and temperature. This system was useful for liver preservation and for evaluating the graft viability and recovery of functions during machine perfusion before transplantation. This novel rewarming machine preservation system was tested in an experimental model using porcine liver grafts. We report that this system has certain advantages in liver preservation, and believe that this system will positively contribute to the expansion of the organ donor pool.

Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation

BACKGROUND & AIMS

The aim of this study was to examine the development of biliary epithelial damage between organ retrieval and transplantation and its clinical relevance for patients.

METHODS

Common bile duct samples during donor hepatectomy, after cold storage, and after reperfusion were compared to healthy controls by hematoxylin and eosin (H&E) staining and immunofluorescence for tight junction protein 1 and Claudin-1. A bile duct damage score to quantify biliary epithelial injury was developed and correlated with recipient and donor data and patient outcome.

RESULTS

Control (N=16) and donor hepatectomy bile ducts (N=10) showed regular epithelial morphology and tight junction architecture. After cold storage (N=37; p=0.0119), and even more after reperfusion (N=62; p=0.0002), epithelial damage, as quantified by the bile duct damage score, was markedly increased, and both tight junction proteins were detected with inappropriate morphology. Patients with major bile duct damage after cold storage had a significantly increased risk of biliary complications (relative risk 18.75; p<0.0001) and graft loss (p=0.0004).

CONCLUSIONS

In many cases, the common bile duct epithelium shows considerable damage after cold ischemia with further damage occurring after reperfusion. The extent of epithelial damage can be quantified by our newly developed bile duct damage score and is a prognostic parameter for biliary complications and graft loss. Possibly, in an intraoperative histological examination, this bile duct damage score may influence decision-making in transplantation surgery.

Crystalloid flush with backward unclamping may decrease post-reperfusion cardiac arrest and improve short-term graft function when compared to portal blood flush with forward unclamping during liver transplantation

During liver transplant (LT), the release of vasoactive substances into the systemic circulation is associated with severe hemodynamic instability that is injurious to the recipient and/or the post-ischemic graft. Crystalloid flush with backward unclamping (CB) and portal blood flush with forward unclamping (PF) are two reperfusion methods to reduce reperfusion-related cardiovascular perturbations in our center. The primary aim of this study was to compare these two methods. After institutional review board (IRB) approval, cadaveric whole LT cases performed between 2003 and 2008 were reviewed. Patients were divided into two groups based on reperfusion methods: CB or PF. After background matching with propensity score, the effect of each method on post-operative graft function was assessed in detail. In our cohort of 478 patients, CB was used in 313 grafts and PF in 165. Thirty-day graft survival was lower, and risk of retransplantation was higher in PF. Multivariable model showed that CB is an independent factor to reduce primary non-function, cardiac arrest and improve 30-d graft survival. Also, the incidence of ischemic-type biliary lesions was significantly higher in the PF group. Reperfusion methods affect intraoperative hemodynamics and post-transplant outcome. CB allows for control over temperature and composition of the perfusate, perfusion pressure, and the rate of infusion.

Endoscopic management of biliary complications following liver transplantation after donation from cardiac death donors

BACKGROUND

Previous studies have shown a higher incidence of biliary complications following donation after cardiac death (DCD) liver transplantation compared with donation after brain death (DBD) liver transplantation. The endoscopic management of ischemic type biliary strictures in patients who have undergone DCD liver transplants needs to be characterized further.

METHODS

A retrospective institutional review of all patients who underwent DCD liver transplant from January 2006 to September 2011 was performed. These patients were compared with all patients who underwent DBD liver transplantation in the same time period. A descriptive analysis of all DCD patients who developed biliary complications and their subsequent endoscopic management was also performed.

RESULTS

Of the 36 patients who received DCD liver transplants, 25% developed biliary complications compared with 13% of patients who received DBD liver transplants (P=0.062). All DCD allograft recipients who developed biliary complications became symptomatic within three months of transplantation. Ischemic type biliary strictures in DCD allograft recipients included disseminated biliary strictures in two patients, biliary strictures of the hepatic duct bifurcation in three patients and biliary strictures of the donor common hepatic duct in three patients.

CONCLUSIONS

There was a trend toward increasing incidence of total biliary complications in recipients of DCD liver allografts compared with those receiving DBD livers, and the rate of diffuse ischemic cholangiopathy was significantly higher. Focal ischemic type biliary strictures can be treated effectively in DCD liver transplant recipients with favourable results. Diffuse ischemic type biliary strictures in DCD liver transplant recipients ultimately requires retransplantation.

Establishment of a rat liver transplantation model with prolonged biliary warm ischemia time

AIM: To investigate the impact of different time points of secondary warm ischemia on bile duct in a rat autologous liver transplantation model with external bile drainage.

METHODS: One hundred and thirty-six male inbred SD rats were randomly assigned to one of four groups (I-IV) according to the secondary warm ischemia time of 0, 10, 20 and 40 min. A rat model of autologous liver transplantation with continuous external biliary drainage under ether anesthesia was established. Ten rats in each group were used to evaluate the one-week survival rate. At 6 h, 24 h, 3 d and 7 d after reperfusion of the hepatic artery, 6 rats were killed in each group to collect the blood sample via the infrahepatic vena cava and the median lobe of liver for assay. Warm ischemia time of liver, cold perfusion time, anhepatic phase, operative duration for biliary external drainage and survival rates in the four groups were analyzed for the establishment of models.

RESULTS: No significant difference was shown in warm ischemia time, anhepatic phase and operative duration for biliary external drainage among the four groups. Five of the 40 rats in this study evaluated for the one-week survival rate died, including three deaths of severe pulmonary infection in group IV. A significant decrease of one-week survival rate in group IV was noted compared with the other three groups. With the prolongation of the biliary warm ischemia time, the indexes of the liver function assessment were significantly elevated, and biliary epithelial cell apoptosis index also increased. Pathological examinations showed significantly aggravated inflammation in the portal area and bile duct epithelial cell injury with the prolonged secondary warm ischemia time. Microthrombi were found in the micrangium around the biliary tract in some sections from groups III and IV.

CONCLUSION: The relationship between secondary warm ischemia time and the bile duct injury degree is time-dependent, and 20 min of secondary warm ischemia time is feasible for the study of bile duct injury.

Effects of warm ischemia time on biliary injury in rat liver transplantation

AIM: To investigate the effect of different secondary warm ischemia time (SWIT) on bile duct injury in liver-transplanted rats.

METHODS: Forty-eight male inbred Sprague-Dawley rats were randomly assigned into four groups: a sham-operation group and three groups with secondary biliary warm ischemia time of 0 min, 10 min and 20 min. A rat model of autologous liver transplantation under ether anesthesia was established, and six rats were killed in each group and blood samples and the median lobe of the liver were collected for assay at 6 h and 24 h after hepatic arterial reperfusion.

RESULTS: With prolongation of biliary warm ischemia time, the level of vascular endothelial growth factor-A was significantly decreased, and the value at 24 h was higher than that at 6 h after hepatic arterial reperfusion, but with no significant difference. The extended biliary SWIT led to a significant increase in bile duct epithelial cell apoptosis, and a decrease in the number of blood vessels, the bile duct surrounding the blood vessels and bile duct epithelial cell proliferation in the early postoperative portal area. Pathologic examinations showed that inflammation of the rat portal area was aggravated, and biliary epithelial cell injury was significantly worsened.

CONCLUSION: A prolonged biliary warm ischemia time results in aggravated injury of the bile duct and the surrounding vascular plexus in rat autologous orthotopic liver transplantation.

Effects of autologous bone marrow mononuclear cells implantation on cholangiocytes apoptosis in model of intrahepatic ischemic type biliary lesion in rabbits

AIM

To investigate the effects of autologous bone marrow mononuclear cells (BM-MNCs) implantation on regulation of cholangiocyte apoptosis in a model of intrahepatic ischemic type biliary lesion (ITBL) in rabbits.

MATERIALS AND METHODS

Thirty Japanese white rabbits were divided randomly into 3 groups (10 per group) including controls (group A), ITBL model (group B), and BM-MNCs implantation groups (group C). All rabbits underwent the same surgical procedure to prepare the liver for graft removal during transplantation. Subsequently, no additional vascular intervention was performed in group A. In group B, the hepatic artery and common bile duct were clamped with microvascular clips for 2 hours, where after the clips were removed to recover the blood supply. Group C received, BM-MNCs (10(8) cells per rabbit) injected through the hepatic artery after removing the clips. The animals were killed 4 weeks after operation. The survival rate, histopathologic examination, cholangiocyte apoptosis with terminal uridine nick-end labeling (TUNEL) staining and expressions of Bcl-2 and Bax proteins were examined using immunohistochemical staining.

RESULTS

Group A animals showed a survival of 100%; the rates in groups B and C were both 90%. Histopathologic examination revealed normal intrahepatic cholangiocytes in group A, obviously damaged ones in group B, and alleviated damage in group C. TUNEL staining indicated apoptosis of cholangiocytes in group B was more serious than that in group A or group C. Immunohistochemical staining demonstrated significantly decreased Bcl-2 expression in group B compared with that in group A; Bcl-2 expression in group C returned to the level of group A. Simultaneously, the Bax expression presented adverse results; the ratios of Bcl-2/Bax were ranked as group A > group C > group B.

CONCLUSION

Implantation of autologous BM-MNCs significantly reduced apoptosis of intrahepatic cholangiocytes and prevented or abated intrahepatic ITBL.

Preexcisional artery reconstruction: a new strategy in multiple hepatic artery reconstruction for reducing ischemic injury of the liver

Multiple reconstructions of the hepatic arteries (HA) after cancer resection presents a surgical challenge, not only because it is technically demanding, but also because attention must be paid to potential ischemic injury to the liver caused by the prolonged ischemia. We present a novel "preexcisional artery reconstruction" method for minimizing ischemic injury of the liver. A 65-year-old woman presented with cholangiocarcinoma invading the HA. Pancreatoduodenectomy, resection, and multiple reconstruction of the HA were performed. First, the left hepatic artery (LHA) was reconstructed prior to the tumor resection. During this procedure, blood supply was maintained to most of the liver via the right hepatic artery (RHA). Then, resection of the tumor en bloc with the HA was performed, followed by reconstruction of the RHA. During this procedure, blood supply was maintained via the already-reconstructed LHA, thereby limiting the ischemic area. Use of this method allowed the ischemia time and region to be divided and minimized, thereby leading to a reduced risk of ischemia-related complications. We believe that this method may be one of the useful approaches in multiple HA reconstruction.

Simultaneous surgical repair for combined biliary and arterial stenoses after liver transplantation

After orthotopic liver transplantation (OLT), hepatic artery stenoses (HAS) and biliary strictures (BS) are frequent. These complications remain a significant cause of graft loss and patient death. The present study reported a group of 7 patients in whom both HAS and BS were identified and treated surgically in the same surgical session. The median times to diagnosis were 42 (range, 5-120) and 84 (range, 15-280) days after OLT for biliary and arterial stenosis, respectively. The mortality was nil. Two patients (28%) developed postoperative complications. The median hospital stay was 16 days (range, 10-42). All patients are alive; there was no graft loss. With a median of 76 months' follow-up (range, 38-132), only 1 patient (14%) developed recurrence of both BS and HAS. In patients with coincident biliary and artery stenosis, concomitant surgical repair is feasible, offering good long-term results.

Does arterialisation time influence biliary tract complications after orthotopic liver transplantation?

BACKGROUND

In the cardiac death donor era, many reports deal with biliary tract complications and concerns about ischemic reperfusion injury owing to the exclusive arterial vascularization of the biliary tree, the warm ischemia time has been implicated as responsible for biliary lesions during organ procurement. We defined the arterialization time as the second warm ischemia time. Our purpose was to study the correlation between the arterialization time during liver implantation and the appearance of biliary lesions.

METHODS

We retrospectively collected data from the last 5-years of orthotopic liver transplantation: namely, indications, cold perfusion fluid, cold ischemia time, operative procedure times, and acute rejection events. We excluded split-liver transplantations, retransplantations, pediatric patients, transplantations for cholestatic disease, cases where hepatic artery thrombosis happened before biliary complications, or patients with posttransplant cytomegalovirus infection. We defined 2 groups: A) without biliary complications; and B) with biliary complications. We compared the mean arterialization time using Student t test to define whether the warm ischemic time during implantation was responsible for biliary tract complications. A P value of <.05 was considered to be significant.

RESULTS

Between 2004 and the end of 2008, we grafted 402 patients among whom 243 met the inclusion criteria: 198 in group A and 45 in group B. Only the cold ischemia time was significantly different between the 2 groups (P = .039).

CONCLUSION

After the anhepatic time, the surgeon may take time for the arterial anastomosis without fearing increased biliary damage.

Steatosis of the hepatic graft as a risk factor for post-transplant biliary complications

BACKGROUND

Despite recent advances in organ preservation, immunosuppression, and surgical techniques, the biliary tree is still considered the Achilles' heel of liver transplantation. The aim of this study is to retrospectively analyze the incidence of biliary complications and identify risk factors that might predispose to the development of biliary problems.

METHODS

From January 2004 to December 2007, 117 consecutive liver transplantations were retrospectively analyzed for the development of biliary complications by the review of medical records. Patients were divided into group 1 with biliary complications (n = 43) and group 2 without biliary complications (n = 74).

RESULTS

The overall biliary complication rate was 36.8% (leakage 6% and stricture 30.8%). Univariate analysis indicated that significant predictors of biliary complications were the time interval between portal and arterial reperfusion (p = 0.037) and macrovacuolar steatosis of the graft > 25% (p = 0.004). Stepwise logistic regression model demonstrated that a macrosteatosis of the graft > 25% (OR = 5.21 CI 95% [1.79-15.15], p = 0.002) was the only independent risk factor predicting biliary complications after liver transplantation. No differences in patient's and graft's survival were noted between the two groups.

CONCLUSION

According to our experience, transplanting a liver with > 25% of steatosis is a risk factor for the development of biliary complication.

De novo cholangiocarcinoma after liver transplantation in a pediatric patient

To date, no child has been reported to develop de novo CCA after liver transplantation although patients with transplants have a significantly higher risk of malignancy than the general population. CCA is extremely rare in the pediatric age group, seen mostly in patients with a history of choledochal cysts, Caroli's disease, or PSC. We report the first case of pediatric de novo CCA in the liver allograft 12 yr after liver transplantation.

RhGH attenuates ischemia injury of intrahepatic bile ducts relating to liver transplantation

BACKGROUND

To study the effect of rhGH administration on intrahepatic cholangiocytes relating to liver transplantation with ischemia of hepatic artery, and ultimately, clarify pathologic mechanism of the injury.

METHODS

Rat orthotopic autologous liver transplantation was performed first. Three hours later, the rats were grouped as followed: HAL (hepatic artery ligation) group; HAL + rhGH (hepatic artery ligation followed by rhGH administration) group; CON (without hepatic artery ligation) group. Specimen was collected after 7 d. ALT and ALP of serum were measured. The pathologic changes of bile ducts of liver tissue were observed. The number of bile ducts and blood vessels in portal area were counted. Immunochemistry for VEGF, VEGFR-2, VEGFR-3, GHR, and IGF-1R of intrahepatic cholangiocytes was performed. Cholangiocytes apoptosis was evaluated by TUNEL analysis. Cholangiocytes proliferation was evaluated by PCNA immunolabeling.

RESULTS

ALT and ALP of HAL + rhGH group were significantly ameliorated compared with untreated animals (P < 0.05). ALT and ALP of HAL group were significantly higher compared with CON group (P < 0.05). In HAL group, the main injury of bile ducts was not reversible, whereas it was reversible in CON and rhGH groups. In HAL group, the number of bile ducts in portal area decreased, while the number of bile ducts not accompanying blood vessels increased (P < 0.05). In rhGH group, the number of bile ducts in portal area increased, while the number of bile ducts accompanying blood vessels increased compared with HAL group (P < 0.05). The expression of VEGF, VEGFR-2, VEGFR-3, GHR, and IGF-1R was significantly lower in HAL group than in CON group (P < 0.05). Following administration of rhGH to HAL rats, the expression of VEGF, VEGFR-2, VEGFR-3, IGF-1R, and GHR was significantly higher (P < 0.05). Administration of rhGH prevented increase in cholangiocytes apoptosis induced by HAL (P < 0.05). Administration of rhGH promoted increase in cholangiocytes proliferation held by HAL (P < 0.05).

CONCLUSIONS

Administration of rhGH appears to attenuate ischemia injury of intrahepatic bile ducts relating to liver transplantation. This function is partly related to the capacity that rhGH inhibits the apoptosis of intrahepatic cholangiocytes and prompts the proliferation and angiogenesis by increasing the expression of VEGF, VEGFR2, VEGFR3, GHR, and IGF1-R.

Endovascular treatment of hepatic artery thrombosis following liver transplantation

Hepatic artery thrombosis (HAT) is the most frequent vascular complication following orthotopic liver transplantation. Urgent retransplantation has been considered as the mainstay therapy. Surgical revascularization is an effective alternative in asymptomatic patients. Endovascular therapies including intra-arterial thrombolysis, percutaneous transluminal angioplasty (PTA), and stent placement have shown encouraging results in recent years; however, their use remains controversial because of potential risk of hemorrhage. Until June 2009, 69 cases were published in 16 reports describing therapeutic potential of endovascular modalities. Interventions were performed as early as within 4 h to as late as 120 days in patients ranging from 4 months to 64 years of age. Majority of published reports suggested the use of urokinase. Thrombolysis was successful in 47 out of 69 (68%) patients. Bleeding was the most common complication including fatal intra-abdominal hemorrhage in three patients. Twenty-nine out of 47 (62%) patients underwent further intervention in the form of PTA, stenting, or both. The follow-up patency ranged from 1 month to 26 months. In conclusion, whenever possible, efforts should be made to rescue the liver grafts through urgent revascularization (surgical and/or endovascular) depending on patient's condition and interventional expertise at the transplant center; reserving the option of retransplantation for failure, complications, and cases with severe clinical symptoms or allograft dysfunction.

Hepatobiliary scintigraphy for the assessment of biliary strictures after pediatric liver transplantation

HBS is used in the management of liver transplantation, a significant complication of which is biliary stricture. Strictures may be intraparenchymal within segments and main duct (non-anastomotic) or at the biliary-enteric anastomosis (anastomotic). Strictures are definitively diagnosed, and often managed, by PTC. This is invasive, technically challenging, and requires general anesthesia in young children. HBS may allow early detection of these complications and is non-invasive. The aim of this study was to review the scintigraphic pattern of biliary strictures using (99m)TcDISIDA HBS following pediatric orthotopic liver transplantation, and to assess its role in the diagnostic algorithm of suspected biliary strictures. All available hepatobiliary studies performed post-transplant in 101 episodes of liver transplantation in 92 pediatric patients were reviewed. Twenty-three (23%) patients had known biliary strictures. Twenty-two patients had adequate studies available for review; five had intrahepatic (non-anastomotic) strictures alone, nine had a stricture of the anastomosis alone, and eight had both intrahepatic and anastomotic strictures. HBS patterns (either segmental or global changes) correlated very highly with clinically significant biliary strictures. All patients with known strictures had abnormal HBS; hence, in patients with abnormal liver function tests post-liver transplant, a normal HBS makes strictures very unlikely. We propose that HBS can thus be used to determine if further investigation is required.

Long-term outcomes of emergency liver transplantation for acute liver failure

Acute liver failure continues to be associated with a high mortality rate, and emergency liver transplantation is often the only life-saving treatment. The short-term outcomes are decidedly worse in comparison with those for nonurgent cases, whereas the long-term results have not been reported as extensively. We report our center's experience with urgent liver transplantation, long-term survival, and major complications. From 1994 to 2007, 60 patients had emergency liver transplantation for acute liver failure. The waiting list mortality rate was 6%. The mean waiting time was 2.7 days. Post-transplantation, the perioperative mortality rate was 15%, and complications included neurological problems (13%), biliary problems (10%), and hepatic artery thrombosis (5%). The 5- and 10-year patient survival rates were 76% and 69%, respectively, and the graft survival rates were 65% and 59%. Recipients of blood group-incompatible grafts had an 83% retransplantation rate. Univariate analysis by Cox regression analysis found that cerebral edema and extended criteria donor grafts were associated with worse long-term survival. Severe cerebral edema on a computed tomography scan pre-transplant was associated with either early mortality or permanent neurological deficits. The keys to long-term success and continued progress in urgent liver transplantation are the use of good-quality whole grafts and a short waiting list time, both of which depend on access to a sufficient pool of organ donors. Severe preoperative cerebral edema should be a relative contraindication to transplantation.

Donor graft interferon regulatory factor-1 gene transfer worsens liver transplant ischemia/reperfusion injury

BACKGROUND

Liver ischemia and reperfusion (IR) injury is a phenomenon that leads to graft dysfunction after liver transplantation. Understanding the molecular mechanisms behind this process is crucial to developing strategies to prevent short- and long-term graft dysfunction. The purpose of this study was to explore the role of the transcription factor interferon regulatory factor-1 (IRF-1) in a model of orthotopic rat liver transplantation.

METHODS

Orthotopic syngeneic LEW rat liver transplantation (OLT) was performed after 18 or 3 hours preservation in cold University of Wisconsin solution. Adenovirus-expressing IRF-1 (AdIRF-1) or control gene vector (Adnull) was delivered to the liver by donor intravenous pretreatment 4 days before graft harvesting. Uninfected grafts also served as controls. Recipients were humanely killed 1-24 hours post-transplantation.

RESULTS

Rats that underwent OLT with long-term preserved grafts (18 hours) displayed increased hepatic nuclear expression of IRF-1 protein at 1 and 3 hours. Rats pretreated with AdIRF-1 before transplantation had elevated alanine aminotransferase levels and increased expression of interferon (IFN)-beta, IFN-gamma, interleukin-12, and inducible nitric oxide synthase in the short-term period (3 hours) when compared with donor livers pretreated with Adnull. AdIRF-1 pretreated donor livers also exhibited increased susceptibility to early apoptosis in the transplanted grafts as shown by increased terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) staining and expression of cleaved caspase-3. Additionally, AdIRF-1 pretreated donor livers had increased activation of the MAP kinase Jun N-terminal kinase as compared with Adnull pretreated donor livers.

CONCLUSION

IRF-1 is an important regulator of IR injury after OLT in rats. Targeting of IRF-1 may be a potential strategy to ameliorate ischemic liver injury after transplantation to minimize organ dysfunction.

Endoscopic management of biliary strictures after liver transplantation

Bile duct strictures remain a major source of morbidity after orthotopic liver transplantation (OLT). Biliary strictures are classified as anastomotic or non-anastomotic strictures according to location and are defined by distinct clinical behaviors. Anastomotic strictures are localized and short. The outcome of endoscopic treatment for anastomotic strictures is excellent. Non-anastomotic strictures often result from ischemic and immunological events, occur earlier and are usually multiple and longer. They are characterized by a far less favorable response to endoscopic management, higher recurrence rates, graft loss and need for retransplantation. Living donor OLT patients present a unique set of challenges arising from technical factors, and stricture risk for both recipients and donors. Endoscopic treatment of living donor OLT patients is less promising. Current endoscopic strategies for biliary strictures after OLT include repeated balloon dilations and placement of multiple side-by-side plastic stents. Lifelong surveillance is required in all types of strictures. Despite improvements in incidence and long term outcomes with endoscopic management, and a reduced need for surgical treatment, the impact of strictures on patients after OLT is significant. Future considerations include new endoscopic technologies and improved stents, which could potentially allow for a decreased number of interventions, increased intervals before retreatment, and decreased reliance on percutaneous and surgical modalities. This review focuses on the role of endoscopy in biliary strictures, one of the most common biliary complications after OLT.

Endogenous bile salts are associated with bile duct injury in the rat liver transplantation model

BACKGROUND

Nonanastomotic biliary strictures are a serious complication after orthotopic liver transplantation (OLT) and are difficult to cure. We examined the role of endogenous bile salt toxicity in the pathogenesis of bile duct injury after OLT.

MATERIALS AND METHODS

A total of 90 Sprague-Dawley rats were divided into three groups: Sham-operated group (Sham, n=30), OLT group with 1 hr donor liver preservation (OLT-1h, n=30), and OLT group with 12 hr donor liver preservation (OLT-12h, n=30). Bile was collected and analyzed biochemically. The histopathologic study was performed to determine the intrahepatic bile duct morphologic changes. Hepatic expressions of bile transporters Ntcp, Bsep, Mdr2, and Oatps were detected.

RESULTS

During the first 2 weeks after transplantation, bile salt secretion was not parallel with phospholipid secretion, resulting in high biliary bile salt-to-phospholipid (BS:PL) ratio. The expression of bile transporters was consistent with the change of bile composition. Bile duct injury correlated significantly with bile salt secretion and BS:PL ratio. Moreover, OLT group with longer donor liver preservation time (OLT-12h) had significantly lower Mdr2 messenger RNA/protein level, higher BS:PL ratio, and better correlation between BS:PL ratio and bile duct injury compared with those of OLT-1h.

CONCLUSIONS

The unparallel secretion of bile salts and phospholipids results in cytotoxic bile formation with high BS:PL ratio after liver transplantation. Longer donor liver preservation time will increase graft bile cytotoxicity. The results of this study suggest that endogenous bile salts play a role in the pathogenesis of bile duct injury after OLT.

Establishment of an animal model of ischemic type intrahepatic biliary lesion in rabbits

AIM

To explore a method to establish an animal model of ischemic type intrahepatic biliary lesion in rabbits.

METHODS

Forty Japanese white rabbits of clean grade were divided randomly into four groups (10 rabbits per group) including sham operation (SO) group, and artery-bile obstruction (ABO)-1 h group, ABO-2 h group and ABO-3 h group. All the rabbits in this study underwent the same initial surgical procedure in which the liver was prepared as for graft removal during liver transplantation. Subsequently in the SO group, no additional vascular intervention was performed, while in groups ABO-1 h, ABO-2 h and ABO-3 h, the animals underwent combined clamping of the hepatic artery and common bile duct with microvascular clips for 1, 2 and 3 h, respectively. After the scheduled occlusion time, the clip was removed to recover blood supply. The animals were killed 4 wk after operation. The survival rate, liver function, cholangiography and histopathological manifestation of the rabbits in each group were observed.

RESULTS

The survival rate was 100% in groups SO, ABO-1 h and ABO-2 h, while it was 60% in group ABO-3 h. At each observation time, the change degree of the indexes of liver function was proportional to the clamping time (ABO-3 h > ABO-2 h > ABO-1 h > SO, P < 0.05). Cholangiographical and histopathologic manifestations both showed that intrahepatic biliary lesion aggravated proportionally with the increase of the clamping time.

CONCLUSION

An animal model of ischemic type intrahepatic biliary lesion in rabbits is successfully established, which may provide a reliable technique for basic and clinical research into the etiology, development and prophylaxis of ischemic type intrahepatic biliary lesion after liver transplantation.

Artificial circulation of the liver: machine perfusion as a preservation method in liver transplantation

Due to the sharp increase in liver transplant candidates and the subsequent shortage of suitable donor livers, an extension of the current donor criteria is necessary. Simple cold storage, the current standard in organ preservation has proven to be insufficient to preserve extended criteria donor livers. Therefore a renewed interest grew toward alternative methods for liver preservation, such as hypothermic machine perfusion and normothermic machine perfusion. These "new" preservation methods were primarily assessed in rat models, and only a few clinically relevant large animal models have been described so far. This review will elaborate on these alternative preservation methods.

Preservation of non-heart-beating donor livers in extracorporeal liver perfusion and histidine-trytophan-ketoglutarate solution

AIM: To compare the preservation of non-heart-beating donor (NHBD) livers in cold histidine-trytophan-ketoglutarate (HTK) solution and extracorporeal liver perfusion (ECLP).

METHODS: Livers harvested from health pigs were stored for 10 h in cold HTK solution (group A, n = 4) or perfused with oxygenated autologous blood at body temperature (group B, n = 4). Both groups were then tested on the circuit for 4 h. Bile production, hemodynamic parameters, hepatocyte markers and reperfusion injury of extracorporeal livers were tested in each group. Liver tissues from each group were examined at the end of reperfusion.

RESULTS: At 1, 2, 3 and 4 h after reperfusion, bile production, hemodynamic parameters, hepatocyte markers and reperfusion injury of livers in group A were statistically different from those in group B (P < 0.05 or P < 0.01).

CONCLUSION: ECLP is better than HTK solution to preserve NHBD livers. ECLP can assess the graft viability before liver transplantation.