The Result of Renal Allograft which Lymphocyte Crossmatch is Negatively Converted by Pretransplant Plasmapheresis and 4 γ-globulin

Purpose: Many patients who have an acceptable living-kidney donor do not undergo transplantation because of the presence of antibodies against the donor cells resulting in a positive lymphocyte-crossmatch (LCX). Recently, the combination therapy of plasmapheresis, intravenous gamma-globulin and potent immunosuppression to induce negative conversion of LCX in patients who had positive LCX to their living donors was reported. Our institute gave these patients the combination therapy and reported the results of follow-up done 1~3 years after kidney transplantation. Methods: Eleven patients, who showed positive LCX to their living donors, underwent the conversion trials between January 1, 2002 and March 31, 2004. Combination therapy consisting of plasmapheresis, intravenous gamma globulin injection, tacrolimus, mycophenolate mofetil (MMF) and steroids was used. Plasmapheresis had been done every other day up to 6 times. Kidney transplantations were performed immediately after negative conversion was achieved. Five to ten day-courses of ATG (or OKT3) were used as an induction immunosuppression and tacrolimus, MMF, and steroids as a maintenance immunosuppression. Results: Negative conversions in ten out of eleven patients were achieved. Kidney transplantations in these 10 patients were successfully performed. No hyperacute rejection transpired, although four patients developed acute rejection, whose grafts were all rescued with steroid pulse therapy. Serum creatinine level was 1.57±0.12 ㎎/㎗ (mean±SD) during follow-up periods except for one whose graft was lost to Polyoma virus nephropathy. Conclusion: Nine of the 10 grafts are functioning well for 15~41 months after transplantations. Our results suggest that selected crossmatch positive patients can be transplanted successfully with living donor kidney allograft.ope

Curative Ex Vivo Hepatocyte-Directed Gene Editing in a Mouse Model of Hereditary Tyrosinemia Type 1

Hereditary tyrosinemia type 1 (HT1) is an autosomal recessive disorder caused by deficiency of fumarylacetoacetate hydrolase (FAH). It has been previously shown that ex vivo hepatocyte-directed gene therapy using an integrating lentiviral vector to replace the defective Fah gene can cure liver disease in small- and large-animal models of HT1. This study hypothesized that ex vivo hepatocyte-directed gene editing using CRISPR/Cas9 could be used to correct a mouse model of HT1, in which a single point mutation results in loss of FAH function. To achieve high transduction efficiencies of primary hepatocytes, this study utilized a lentiviral vector (LV) to deliver both the Streptococcus pyogenes Cas9 nuclease and target guide RNA (LV-Cas9) and an adeno-associated virus (AAV) vector to deliver a 1.2 kb homology template (AAV-HT). Cells were isolated from Fah-/- mice and cultured in the presence of LV and AAV vectors. Transduction of cells with LV-Cas9 induced significant indels at the target locus, and correction of the point mutation in Fah-/- cells ex vivo using AAV-HT was completely dependent on LV-Cas9. Next, hepatocytes transduced ex vivo by LV-Cas9 and AAV-HT were transplanted into syngeneic Fah-/- mice that had undergone a two-thirds partial hepatectomy or sham hepatectomy. Mice were cycled on/off the protective drug 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC) to stimulate expansion of corrected cells. All transplanted mice became weight stable off NTBC. However, a significant improvement was observed in weight stability off NTBC in animals that received partial hepatectomy. After 6 months, mice were euthanized, and thorough biochemical and histological examinations were performed. Biochemical markers of liver injury were significantly improved over non-transplanted controls. Histological examination of mice revealed normal tissue architecture, while immunohistochemistry showed robust repopulation of recipient animals with FAH+ cells. In summary, this is the first report of ex vivo hepatocyte-directed gene repair using CRISPR/Cas9 to demonstrate curative therapy in an animal model of liver disease.ope

Current Status of Deceased Donor Liver Transplantation for Alcoholic Liver Disease in Korea in MELD Era

The organ allocation system should be fair and efficient to predict the prognosis of patients with end-stage organ failure. The liver allocation system in Korea was changed to the model for end-stage liver disease (MELD) score system from Child-Turcotte-Pugh score-based status system in 2016. Since then, there have been some changes in matching liver graft to recipients in deceased liver transplantation. The severity of sickness of the end-stage liver failure patients has been increased in the MELD era than before. Since 2013, liver transplantation for alcoholic liver disease has been gradually increasing in Korea. We should take proper evaluation into consideration when we decide early liver transplantation particularly for patients with severe alcoholic hepatitis, who have a high MELD score. Above all, overcoming organ shortage, it is necessary for us to try to increase the number of deceased donors to meet the need for liver transplantation for end-stage liver disease patients.ope

Sustained Perfusion of Revascularized Bioengineered Livers Heterotopically Transplanted Into Immunosuppressed Pigs

Implanted bioengineered livers have not exceeded three days of continuous perfusion. Here we show that decellularized whole porcine livers revascularized with human umbilical vein endothelial cells and implanted heterotopically into immunosuppressed pigs whose spleens had been removed can sustain perfusion for up to 15 days. We identified peak glucose consumption rate as a main predictor of the patency of the revascularized bioengineered livers (rBELs). Heterotopic implantation of rBELs into pigs in the absence of anticoagulation therapy led to sustained perfusion for three days, followed by a pronounced immune responses directed against the human endothelial cells. A 10 day steroid-based immunosuppression protocol and a splenectomy at the time of rBEL implantation reduced the immune responses and resulted in continuous perfusion of the rBELs for over two weeks. We also show that the human endothelial cells in the perfused rBELs colonize the liver sinusoids and express sinusoidal endothelial markers similar to those in normal liver tissue. Revascularized liver scaffolds that can maintain blood perfusion at physiological pressures might eventually help to overcome the chronic shortage of transplantable human livers.ope

Functional characterization of a bioengineered liver after heterotopic implantation in pigs

Organ bioengineering offers a promising solution to the persistent shortage of donor organs. However, the progression of this technology toward clinical use has been hindered by the challenges of reconstituting a functional vascular network, directing the engraftment of specific functional cell types, and defining appropriate culture conditions to concurrently support the health and phenotypic stability of diverse cell lineages. We previously demonstrated the ability to functionally reendothelialize the vasculature of a clinically scaled decellularized liver scaffold with human umbilical vein endothelial cells (HUVECs) and to sustain continuous perfusion in a large animal recovery model. We now report a method for seeding and engrafting primary porcine hepatocytes into a bioengineered liver (BEL) scaffold previously reendothelialized with HUVECs. The resulting BELs were competent for albumin production, ammonia detoxification and urea synthesis, indicating the presence of a functional hepatocyte compartment. BELs additionally slowed ammonia accumulation during in vivo perfusion in a porcine model of surgically induced acute liver failure. Following explant of the graft, BEL parenchyma showed maintenance of canonical endothelial and hepatocyte markers. Taken together, these results support the feasibility of engineering a clinically scaled functional BEL and establish a platform for optimizing the seeding and engraftment of additional liver specific cells.ope

Organ procurement in a deceased donor

With the increasing demand for organ transplantation, organ procurement from a deceased donor is an essential step for deceased donor organ transplantation. A proper surgical technique for the procurement of an organ graft from a deceased donor must be carried out to avoid any damage to it. Moreover, how to manage deceased donors until they enter the operating room in a stable condition is a critical point to be considered. The establishment of a surgical technique and preoperative management for organ procurement is encouraged to achieve a nationwide standard and consistency for organ graft sharing among the transplant units.ope

Diagnostic Role of Tumor Markers for Hepatocellular Carcinoma in Liver Transplantation Candidates: An Analysis Using the Korean Organ Transplantation Registry Database

BACKGROUND This study analyzed pretransplant alpha-fetoprotein (AFP) and proteins induced by vitamin K absence or antagonist-II (PIVKA-II) in liver transplantation (LT) candidates. MATERIAL AND METHODS A total of 3,273 LT recipients enrolled at the Korean Organ Transplantation Registry were divided according to hepatocellular carcinoma (HCC) status and background liver disease, and AFP and PIVKA-II were compared. RESULTS In all patients, the median AFP and PIVKA-II were 6.3 ng/mL and 29 mAU/mL in the viable-HCC group and 3.3 ng/mL and 35 mAU/mL, respectively, in the no-HCC group (P<0.001 for AFP and p=0.037 for PIVKA-II). In patients with hepatitis B virus infection, they were 6.0 ng/mL and 26 mAU/mL in the HCC group and 3.2 ng/mL and 21 mAU/mL in the no-HCC group, respectively (P<0.001 and P<0.001). In patients with hepatitis C virus infection, they were 10.7 ng/mL and 37 mAU/mL in the HCC group and 2.6 ng/mL and 21 mAU/mL in the no-HCC group, respectively (P<0.001 and P=0.117). In alcoholic liver disease patients, they were 5.2 ng/mL and 61 mAU/mL in the HCC group and 6.4 ng/mL and 75 mAU/mL in the no-HCC group, respectively (P<0.001 and P=0.419). In patients with other diseases, they were 7.1 ng/mL and 32 mAU/mL in the HCC group and 3.3 ng/mL and 28 mAU/mL in the no-HCC group, respectively (P<0.001 and P=0.822). CONCLUSIONS The results of the present study indicate that pretransplant serum AFP and PIVKA-II were highly variably expressed in LT candidates with end-stage liver diseases; therefore, their values should be cautiously interpreted because their role in HCC diagnosis is limited.ope

Efficacy and safety of a switch from twice-daily tacrolimus to once-daily generic tacrolimus in stable liver transplant patients

Background: Once-daily tacrolimus reduces non-compliance relative to twice-daily tacrolimus. However, little is known about the safety and efficacy of conversion from twice-daily tacrolimus to generic once-daily tacrolimus in liver transplantation (LT). Herein, we investigated the efficacy and safety of a switch from twice-daily tacrolimus to generic once-daily tacrolimus in patients with stable liver graft function. Methods: This prospective, multicenter, open-label, single-arm study was conducted in 17 medical centers for 1 year from July 2019 to July 2020 (NCT04069065). Primary endpoint was the incidence of biopsy-proven acute rejection (BPAR) for 24 weeks after conversion. Secondary endpoints were graft failure, patient death, and adverse events (AEs). Results: Of 151 screened LT patients, 144 patients were enrolled. BPAR, graft failure, and patient death did not occur in this patient population. There were no statistical differences in blood tests, liver function tests, or biochemical tests between visits in any of the patients. Median tacrolimus trough level decreased abruptly from 4.7 ng/mL to 3.2 ng/mL after generic once-daily tacrolimus conversion, but median tacrolimus dose increased due to low tacrolimus trough level. Ninety-two adverse events occurred in 54 patients. Liver enzyme levels increased in seven patients (4.9%) after the switch to generic once-daily tacrolimus, but the liver function tests of these patients normalized thereafter. There were three cases of severe AEs not related to investigational drug. Conclusions: Present study suggests that conversion from twice-daily tacrolimus to generic once-daily tacrolimus is effective and safe in stable LT patients.ope

Long-Term Effects of Everolimus-Facilitated Tacrolimus Reduction in Living-Donor Liver Transplant Recipients with Hepatocellular Carcinoma

BACKGROUND The study objective was to evaluate the effect of everolimus (EVR) in combination with reduced tacrolimus (rTAC) compared with a standard TAC (sTAC) regimen on hepatocellular carcinoma (HCC) recurrence in de novo living-donor liver transplantation recipients (LDLTRs) with primary HCC at liver transplantation through 5 years after transplantation. MATERIAL AND METHODS In this multicenter, non-interventional study, LDLTRs with primary HCC, who were previously randomized to either everolimus plus reduced tacrolimus (EVR+rTAC) or standard tacrolimus (sTAC), and who completed the 2-year core H2307 study, were followed up. Data were collected retrospectively (end of core to the start of follow-up study), and prospectively (during the 3-year follow-up study). RESULTS Of 117 LDLTRs with HCC at LT in the core H2307 study (EVR+rTAC, N=56; sTAC, N=61), 86 patients (EVR+rTAC, N=41; sTAC, N=45) entered the follow-up study. Overall HCC recurrence was lower but statistically non-significant in the EVR+rTAC group (3.6% vs 11.5% in sTAC; P=0.136) at 5 years after LT. There was no graft loss or chronic rejection. Acute rejection and death were comparable between treatment groups. Higher mean estimated glomerular filtration rate in the EVR+rTAC group (76.8 vs 65.8 mL/min/1.73 m² in sTAC) was maintained up to 5 years. Reported adverse events were numerically lower in the EVR+rTAC group (41.0% vs 53.5% sTAC) but not statistically significant. CONCLUSIONS Although statistically not significant, early EVR initiation reduced HCC recurrence, with comparable efficacy and safety, and better long-term renal function, than that of sTAC treatment.ope

Invasive fungal infection in liver transplant recipients in a prophylactic era: A multicenter retrospective cohort study in Korea

The epidemiology of invasive fungal infections (IFIs) after liver transplantation (LT) is continuing to evolve in the current era of antifungal prophylactic therapy. This multicenter retrospective cohort study aimed to evaluate the epidemiology, risk factors, and outcomes of IFIs among LT recipients in the current era.We analyzed a total of 482 LT recipients aged 18 years and older who were admitted to 3 tertiary hospitals in Korea between January 2009 and February 2012.Twenty-four episodes of IFIs occurred in 23 patients (4.77%; 23/482). Of these episodes, 20 were proven cases and 4 were probable cases according to EORTC/MSG criteria. Among these cases, IFI developed within 30 days of transplantation in 47.8% of recipients, from 31 to 180 days in 34.8% of recipients, and from 181 to 365 days in 17.4% of recipients. The most common isolates were Candida species (n = 12, 52.2%; Candida albicans, 6 cases; Candida tropicalis, 1 case; Candida glabrata, 1 case; Candida parapsilosis, 1 case; and unspecified Candida species, 1 case) and Aspergillus species (n = 7, 30.4%). The mortality in patients with IFIs was significantly higher than that in patients without IFIs (47.83% [11/23] vs 7.18% [33/459], P < .001). The incidence of late-onset IFIs is increasing in the antifungal prophylactic era, and fluconazole-resistant non-albicans Candida species have not yet emerged in Korea.ope