Transcriptomic profiles of human livers undergoing rewarming machine perfusion before transplantation-first insights.

Machine perfusion by controlled oxygenated rewarming (COR) is feasible and safe in clinical application and result in a promising outcome. This study utilizes next-generation sequencing (NGS) to investigate the transcriptome of human liver tissue undergoing COR before liver transplantation. Cold-stored livers were subjected to machine-assisted slow COR for ~120 min before transplantation. Biopsies were taken before (preCOR) and after COR (postCOR) and 1 h after reperfusion (postRep). The samples were sequenced, using RNA-seq to analyze differential transcriptional changes between the different stages and treatments of the grafts. Comparison of differential gene expression preCOR and postCOR demonstrated 10 upregulated genes. postRep 97 and 178 genes were upregulated and 7 and 13 downregulated compared to preCOR and postCOR, respectively. A shift of gene expressions by machine perfusion to the TGF-beta pathway was observed. The present study demonstrates distinct transcriptome profiles associated with machine perfusion by COR and transplantation of human livers. Such data provide a deeper understanding of the molecular mechanisms of machine perfusion technology in human liver transplantation.

Kidney transplantation with allografts from infant donors-Small organs, big value.

BACKGROUND: Although infant organ donors remain a rare source of organs for transplantation, technical challenges have resulted in increased rates of complications and inferior graft function. The aim of the present study was to investigate the outcomes of kidneys procured from juvenile and infant donors. PATIENTS AND METHODS: We evaluated all kidney transplants from deceased donors < 16 years of age performed at our center between 01/2008 and 08/2019. We defined three groups based on quartiles of donor body weight: <13 kg (infant donors), 13-40 kg (juvenile donors), and > 40 kg (standard criteria donors). Clinical characteristics and outcomes were compared between groups. RESULTS: Ninety-two transplants were included in this study. Out of 92 recipients, there were 32 (34.8%) adult and 60 (65.2%) pediatric patients. All groups demonstrated excellent graft function and survival on both short and long-term follow-up. 1-year, 3-year, and 5-year graft survival rates for the standard criteria donor group were 100%, 95.2%, and 88.4%, respectively, compared with 95.8% for infant and 95% for juvenile donors at all times (P = .79). eGFR at 5 years was 98.9 ± 5.5, 74.1 ± 6.2, and 81.6 ± 6.9 mL/min/1.73 m2 for infant, juvenile, and standard criteria donors, respectively (P < .01). CONCLUSION: Infant donor allografts can be transplanted with excellent long-term outcomes in both pediatric and adult recipients. Implanting them as single allografts onto pediatric candidates allows for the transplantation of two patients. As such, pediatric recipients should be prioritized for these donor organs.

Risk Factors for High Mortality on the Liver Transplant Waiting List in Times of Organ Shortage: A Single-Center Analysis.

BACKGROUND Germany has the highest rate of patients dying or becoming unfit for transplant while waitlisted within the Eurotransplant region. Therefore, the aim of the current study was to analyze mortality as well as risk factors for mortality of candidates listed for liver transplantation at our center. MATERIAL AND METHODS Between 01/2011 and 12/2013, 481 adult patients were listed for primary liver transplantation (LT) at a single German center. Clinical and laboratory parameters were prospectively collected and retrospectively analyzed by univariable and multivariable logistic regression and Cox proportional hazards. RESULTS The mean model for end-stage liver disease (MELD) score of all liver transplant waitlist registrants (52.4 years, 60.1% male) was 16.9 (±10.2) at time of listing, with 10% of the listed patients having a MELD score of >32. After waitlisting, 133 (27.7%) candidates died within the follow-up period. Three-month-survival after listing for transplantation was 89% for patients ultimately receiving LT vs. 71.2% that did not receive LT (p<0.001). Multivariable analysis identified clinical parameters such as ICU treatment, preceding abdominal surgery, variceal bleeding, and ascites, as well as hydropic decompensation, as independent risk factors for waitlist mortality. CONCLUSIONS Consideration of independent risk factors of mortality within the MELD-based allocation system potentially improves assessment of individual urgency and might improve utilization of available organs.

All-In-One: Advanced preparation of Human Parenchymal and Non-Parenchymal Liver Cells.

BACKGROUND & AIMS: Liver cells are key players in innate immunity. Thus, studying primary isolated liver cells is necessary for determining their role in liver physiology and pathophysiology. In particular, the quantity and quality of isolated cells are crucial to their function. Our aim was to isolate a large quantity of high-quality human parenchymal and non-parenchymal cells from a single liver specimen. METHODS: Hepatocytes, Kupffer cells, liver sinusoidal endothelial cells, and stellate cells were isolated from liver tissues by collagenase perfusion in combination with low-speed centrifugation, density gradient centrifugation, and magnetic-activated cell sorting. The purity and functionality of cultured cell populations were controlled by determining their morphology, discriminative cell marker expression, and functional activity. RESULTS: Cell preparation yielded the following cell counts per gram of liver tissue: 2.0 ± 0.4 × 10(7) hepatocytes, 1.8 ± 0.5 × 10(6 )Kupffer cells, 4.3 ± 1.9 × 10(5) liver sinusoidal endothelial cells, and 3.2 ± 0.5 × 10(5) stellate cells. Hepatocytes were identified by albumin (95.5 ± 1.7%) and exhibited time-dependent activity of cytochrome P450 enzymes. Kupffer cells expressed CD68 (94.5 ± 1.2%) and exhibited phagocytic activity, as determined with 1 µm latex beads. Endothelial cells were CD146(+) (97.8 ± 1.1%) and exhibited efficient uptake of acetylated low-density lipoprotein. Hepatic stellate cells were identified by the expression of α-smooth muscle actin (97.1 ± 1.5%). These cells further exhibited retinol (vitamin A)-mediated autofluorescence. CONCLUSIONS: Our isolation procedure for primary parenchymal and non-parenchymal liver cells resulted in cell populations of high purity and quality, with retained physiological functionality in vitro. Thus, this system may provide a valuable tool for determining liver function and disease.

Oil Red O-assessed macrosteatosis in liver transplant donor biopsies predicts ischemia-reperfusion injury and clinical outcome.

Steatosis in donor livers is an accepted adverse prognostic factor after liver transplantation. While its semiquantitative assessment shows varying reproducibility, it is questioned as a standard method. Additionally, the influence of hepatic steatosis on ischemia/reperfusion injury (I/R injury) has not been evaluated in biopsies after reperfusion. We compared different staining and analyzing methods for the assessment of donor liver steatosis in order to predict I/R injury and clinical outcome after transplantation. To do this, 56 paired pre- and post-reperfusion liver biopsies were analyzed for macro- (MaS)/micro- (MiS) and total steatosis in cryo and permanent sections by special fat (Oil Red O or ORO) and standard stains. Computerized morphometrical analyses were compared to the semiquantitative assessment by a pathologist. I/R injury was determined histopathologically and by M30 immunohistochemistry. We found ORO to be more sensitive in detecting hepatic steatosis with higher reproducibility for MaS. Semiquantitative analyses were highly reproducible and not inferior to computerized morphometry. Categorized MaS as determined by ORO correlated with the extent of I/R injury, initial poor function, liver enzymes, and survival. Therefore fat stains like ORO are a reliable and easy method comprising significant advantages in the evaluation of hepatic steatosis and are thereby of prognostic value. Computerized analysis is a precise tool though not superior to semiquantitative analyses.