Characterization of hepatic steatosis using controlled attenuation parameter and MRI-derived proton density fat fraction in living donor liver transplantation.

BACKGROUND: The increasingly favorable outcomes of live donor liver transplant warrant development of screening techniques to expand current donor pool. Transient elastography (TE) with controlled attenuation parameter (CAP) is accessible and has promising diagnostic performance in non-obese individuals. Here, we demonstrate its utility in grading donor steatosis for risk assessment in living liver donors (LLD). STUDY DESIGN: In a prospective study of LLD and recipients, accuracy was determined using MRI-derived proton density fat fraction (PDFF) as reference. RESULTS: One hundred and one LLD underwent TE, 95 of whom had available PDFF. Median CAP and MRI-PDFF were 233 dB/m (206-270) and 2.9% (2.3-4.0), respectively. A CAP threshold of 270 dB/m captured all steatosis which was present in 13 (13%) LLD (AUROC .942, 100% sensitivity and 83% specificity). Performance further improved when excluding obese LLD and limiting analysis to M-probe (AUROC .971 and .974, respectively, with 87% specificity). There was no difference in CAP and MRI-PDFF between LLD and nondonors (P = .26 and .21, respectively). Early allograft dysfunction was observed in one recipient (CAP 316, PDFF 9.5%), zero underwent retransplant, and one died from sepsis. CONCLUSION: The specific role of CAP in living liver donation warrants further study, beginning with its use as screening tool across peripheral clinics.

Treprostinil Supplementation Ameliorates Hepatic Ischemia Reperfusion Injury and Regulates Expression of Hepatic Drug Transporters: An Isolated Perfused Rat Liver (IPRL) Study.

PURPOSE: IR injury is an unavoidable consequence in deceased donor liver transplantation. Cold preservation and warm reperfusion may change the expression and function of drug transporters in the liver due to vasoconstriction, infiltration of neutrophils and release of cytokines. We hypothesize that vasodilation, anti-platelet aggregation and proinflammatory downregulation activities of treprostinil will diminish the IR injury and its associated effects. METHODS: Livers obtained from male SD rats (n = 20) were divided into 1) Control, 2) IR, 3) Treprostinil-1 (preservation only), and 4) Treprostinil-2 (preservation and reperfusion) groups. Control livers were procured and immediately reperfused. Livers in the other groups underwent preservation for 24 h and were reperfused. All the livers were perfused using an Isolated Perfused Rat Liver (IPRL) system. Periodic perfusate, cumulative bile samples and liver tissue at the end of perfusion were collected. Liver injury markers, bile flow rates, m-RNA levels for uptake and efflux transporters (qRT-PCR) were measured. RESULTS: Cold preservation and warm reperfusion significantly increased the release of AST and ALT in untreated livers. Treprostinil supplementation substantially reduced liver injury. Bile flow rate was significantly improved in treprostinil-2 group. m-RNA levels of Slc10a1, Slc22a1, and Slc22a7 in liver were increased and m-RNA levels of Mdr1a were decreased by IR. Treprostinil treatment increased Abcb11 and Abcg2 m-RNA levels and maintained Slc22a1m-RNA similar to control livers. CONCLUSIONS: Treprostinil treatment significantly reduced liver injury. IR injury changed expression of both uptake and efflux transporters in rat livers. Treprostinil significantly altered the IR injury mediated changes in m-RNA expression of transporters.

Poor Outcomes of Patients With NAFLD and Moderate Renal Dysfunction or Short-Term Dialysis Receiving a Liver Transplant Alone.

The outcomes of patients with moderate renal impairment and the impact of liver disease etiology on renal function recovery after liver transplant alone (LTA) are largely unknown. We explored whether NAFLD patients with pre-LTA moderate renal dysfunction (GFR 25-45 ml/min/1.73 m2) may be more susceptible to develop post-LTA severe renal dysfunction (GFR<15 ml/min/1.73 m2) than ALD patients, as well as other overall outcomes. Using the UNOS/OPTN database, we selected patients undergoing liver transplant for NAFLD or ALD (2006-2016), 15,103 of whom received LTA. NAFLD patients with moderate renal dysfunction were more likely to develop subsequent GFR<15 ml/min/1.73 m2 than ALD patients (11.1% vs. 7.38%, p < 0.001). Patients on short-term dialysis pre-LTA (≤12 weeks) were more likely to develop severe renal dysfunction (31.7% vs. 18.1%), especially in NAFLD patients, and were more likely to receive a further kidney transplant (15.3% vs. 3.7%) and had lower survival (48.6% vs. 50.4%) after LTA (p < 0.001 for all). NAFLD was an independent risk factor for post-LTA severe renal dysfunction (HR = 1.2, p = 0.02). NAFLD patients with moderate renal dysfunction and those receiving short-term dialysis prior to LTA are at a higher risk of developing subsequent severe renal dysfunction. Underlying etiology of liver disease may play a role in predicting development and progression of renal failure in patients receiving LTA.

Prehabilitation-Driven Changes in Frailty Metrics Predict Mortality in Patients With Advanced Liver Disease.

INTRODUCTION: Frailty is a predictor of morbidity and mortality in cirrhosis. Although evidence for prehabilitation is promising, the data for liver transplant (LT) candidates are limited. The primary aim of this study was to evaluate the effect of a novel prehabilitation strategy on changes in frailty metrics and survival in LT candidates. The secondary aim was to determine liver-related and extrahepatic conditions associated with frailty. METHODS: In this ambispective cohort study, all patients underwent frailty assessment using the liver frailty index (LFI), 6-minute walk test, and gait speed test performed by a dedicated physical therapist. Home-based exercise prescription was individualized to each patient's baseline physical fitness. RESULTS: We included 517 patients (59% men, median age 61 years, and a model for end-stage liver disease score of 12) evaluated during 936 PT visits. Frailty metrics were affected by age, sex, and liver-related parameters, but not by model for end-stage liver disease. Patients with nonalcoholic fatty liver disease and alcohol-related cirrhosis had worse frailty metrics by all tools. We demonstrated the feasibility of prehabilitation in improving both LFI and 6-minute walk test, particularly in adherent patients. A median LFI improvement of 0.3 in frail patients was associated with improved survival in univariate analysis. Compliance with physical therapist visits (hazards ratio = 0.35 [0.18-0.67] for 2 visits and hazards ratio = 0.54 [0.31-0.94] for ≥3 visits) was independently associated with increased survival. DISCUSSION: Prehabilitation improves frailty metrics in LT candidates and is associated with a survival advantage. Our findings provide a framework for the standardized prehabilitation program in LT candidates while prioritizing compliance, adherence, and on-training LFI goal accomplishment.

Introducing EL-FIT (Exercise and Liver FITness): A Smartphone App to Prehabilitate and Monitor Liver Transplant Candidates.

Preserved physical function is key for successful liver transplantation (LT); however, prehabilitation strategies are underdeveloped. We created a smartphone application (app), EL-FIT (Exercise and Liver FITness), to facilitate exercise training in end-stage liver disease (ESLD). In this feasibility study, we tested EL-FIT app usage and the accuracy of physical activity data transfer and obtained feedback from initial users. A total of 28 participants used the EL-FIT app and wore a physical activity tracker for 38 ± 12 days (age, 60 ± 8 years; 57% males; Model for End-Stage Liver Disease-sodium, 19 ± 5). There was fidelity in data transfer from the tracker to the EL-FIT app. Participants were sedentary (1957 [interquartile range, 873-4643] steps/day) at baseline. Level of training assigned by the EL-FIT app agreed with that from a physical therapist in 89% of cases. Participants interacted with all app features (videos, perceived exertion, and gamification/motivational features). We rearranged training data to generate heart rate-validated steps as a marker of performance and showed that 35% of the participants had significant increases in their physical performance. Participants emphasized their interest in having choices to better engage in exercise, and they appreciated the sense of community the EL-FIT app generated. We showed that patients with ESLD are able to use and interact with the EL-FIT app. This novel smartphone app has the potential of becoming an invaluable tool for home-based prehabilitation in LT candidates.

Biodegradation of Volatile Chemicals in Soil: Separating Volatilization and Degradation in an Improved Test Setup (OECD 307).

During environmental risk assessments of chemicals, higher-tier biodegradation tests in soil, sediment, and surface-water systems are required using OECD standards 307, 308, and 309 guidelines, respectively. These guidelines are not suitable for testing highly volatile chemicals, and a biometer closed-incubation setup is recommended for testing slightly volatile chemicals. In this setup, the degradation kinetics of highly volatile chemicals can largely be influenced by volatilization. Additionally, guidelines lack sufficient information on test-system geometry and guidance on how to measure and maintain aerobic conditions during the test. Our objectives were (1) to design a closed test setup for biodegradation tests in soil in which the maintaining and measuring of aerobic conditions was possible without the loss of volatile test chemicals and (2) to suggest data-treatment measures for evaluating the degradation kinetics of volatile test chemicals. With the new setup, full-scale OECD 307 tests were performed using the volatile 14C-labeled chemicals decane and tetralin. For both test chemicals, reproducible complete mass balances were observed, and the new setup ensured that the volatilization losses were kept below the mineralized fraction. Based on the obtained data, an extended model was developed that enabled consideration of the volatilization in the modeling of degradation kinetics.

Toxicological and ecotoxicological properties of gas-to-liquid (GTL) products. 2. Ecotoxicology.

Gas-to-liquid (GTL) products are synthetic hydrocarbons produced from natural gas using a catalytic process known as the Fischer-Tropsch process. This process yields a synthetic crude oil that consists of saturated hydrocarbons which can subsequently be refined to a range of products analogous to those obtained from petroleum refining. However, in contrast to their petroleum-derived analogs, GTL products are essentially free of unsaturated or aromatic compounds and do not contain any sulfur-, oxygen-, or nitrogen-containing compounds. Under new chemical substance notification requirements, an extensive testing program covering the entire portfolio of GTL products has been undertaken to assess their hazardous properties to human health and environment. The results of these studies have been summarized in a two-part review. Part 1 provides an overview of the mammalian toxicity hazardous properties of the various GTL products. This second part of the review focuses on the aquatic, sediment, terrestrial, and avian toxicity studies which assess the ecotoxicological hazard profile of the GTL products. Many challenges were encountered during these tests relating to dosing, analysis and interpretation of results. These are discussed with the intent to share experiences to help inform and shape future regulatory mandates for testing of poorly soluble complex substances. As was the case with the mammalian toxicology review, there were a few cases where adverse effects were found, but overall the GTL products were found to exert minimal adverse ecotoxicological effects and these were less severe than effects observed with their conventional, petroleum-derived analogs.

Predicting Hydrocarbon Primary Biodegradation in Soil and Sediment Systems Using System Parameterization and Machine Learning.

Technical complexity associated with biodegradation testing, particularly for substances of unknown or variable composition, complex reaction products, or biological materials (UVCB), necessitates the advancement of non-testing methods such as quantitative structure-property relationships (QSPRs). Models for describing the biodegradation of petroleum hydrocarbons (HCs) have been previously developed. A critical limitation of available models is their inability to capture the variability in biodegradation rates associated with variable test systems and environmental conditions. Recently, the Hydrocarbon Biodegradation System Integrated Model (HC-BioSIM) was developed to characterize the biodegradation of HCs in aquatic systems with the inclusion of key test system variables. The present study further expands the HC-BioSIM methodology to soil and sediment systems using a database of 2195 half-life (i.e., degradation time [DT]50) entries for HCs in soil and sediment. Relevance and reliability criteria were defined based on similarity to standard testing guidelines for biodegradation testing and applied to all entries in the database. The HC-BioSIM soil and sediment models significantly outperformed the existing biodegradation HC half-life (BioHCWin) and virtual evaluation of chemical properties and toxicities (VEGA) quantitative Mario Negri Institute for Pharmacological Research (IRFMN) models in soil and sediment. Average errors in predicted DT50s were reduced by up to 6.3- and 8.7-fold for soil and sediment, respectively. No significant bias as a function of HC class, carbon number, or test system parameters was observed. Model diagnostics demonstrated low variability in performance and high consistency of parameter usage/importance and rule structure, supporting the generalizability and stability of the models for application to external data sets. The HC-BioSIM provides improved accuracy of Persistence categorization, with correct classification rates of 83.9%, and 90.6% for soil and sediment, respectively, demonstrating a significant improvement over the existing BioHCWin (70.7% and 58.6%) and VEGA (59.5% and 18.5%) models. Environ Toxicol Chem 2024;43:1352-1363. © 2024 Concawe. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Unconventional Strategies for Solid Organ Transplantation and Special Transplantation Scenarios.

Solid organ transplantation is the only long-term therapeutic option for patients with end-organ failure but cadaveric and living donor transplant pools are unable to meet the demand for organ transplantation. Newer techniques, innovative strategies and altruistic donors can help bridge this wide gap between the number of organ donors and recipients. Domino liver transplantation, paired organ donation, and ABO incompatible transplants are some of the ways to ensure increased transplant organ availability. Split liver transplantation and ex vivo liver resection and auto transplantation are considered surgically challenging but are being done at tertiary transplant centers.

Ultrasound-Targeted Microbubble Cavitation During Machine Perfusion Reduces Microvascular Thrombi and Graft Injury in a Rat Liver Model of Donation After Circulatory Death.

BACKGROUND: Ischemic cholangiopathy is a process of bile duct injury that might result from peribiliary vascular plexus (PBP) thrombosis and remains a dreaded complication in liver transplantation from donors after circulatory death (DCD). The aim of this study was to propose a mechanical method of clot destruction to clear microvascular thrombi in DCD livers before transplantation. METHODS: Sonothrombolysis (STL) is a process by which inertial cavitation of circulating microbubbles entering an ultrasound field create a high-energy shockwave at a microbubble-thrombus interface, causing mechanical clot destruction. The effectiveness of STL in DCD liver treatment remains unclear. We carried out STL treatment during normothermic, oxygenated, ex vivo machine perfusion (NMP), introducing microbubbles into the perfusate with the liver enveloped in an ultrasound field. RESULTS: The STL livers showed reduction in hepatic arterial and PBP thrombus and decreases in hepatic arterial and portal venous flow resistance, reduced parenchymal injury as measured by aspartate transaminase release and oxygen consumption, and improved cholangiocyte function. Light and electron microscopy showed reduction of hepatic arterial and PBP thrombus in STL livers compared with controls and preserved hepatocyte structure, sinusoid endothelial morphology, and biliary epithelial microvilli. CONCLUSION: In this model, STL improved flow and functional measures in DCD livers undergoing NMP. These data suggest a novel therapeutic approach to treat PBP injury in DCD livers, which may ultimately increase the pool of grafts available to patients awaiting liver transplantation.

Improved closed test setup for biodegradation testing of slightly volatile substances in water-sediment systems (OECD 308).

Standardized biodegradation testing methods, like the OECD 308 Aerobic and Anaerobic Transformation in Aquatic Sediment Systems, generate data on biodegradation required during environmental risk and hazard assessment of chemicals under different European and international regulations. However, difficulties arise when applying the OECD 308 guideline for testing hydrophobic volatile chemicals. Especially the use of a co-solvent (like acetone) as a measure to facilitate the application of the test chemical in combination with a closed setup to reduce losses due to volatilization tend to deplete/restrict the amount of oxygen in the test system. The result is a low oxygen or even anoxic water column in the water-sediment system. Thus, the degradation half-lives of the chemical generated from such tests are not directly comparable to the regulatory half-life values for Persistence assessment of the test chemical. The aim of this work was to further develop the closed setup to improve and maintain aerobic conditions in the water phase of the water-sediment systems for testing slightly volatile hydrophobic test chemicals. This improvement was attained by optimizing the test system geometry and agitation technique to maintain aerobic conditions in the water phase in a closed test setup, investigating appropriate co-solvent application strategy, and trialing the resulting test setup. This study shows that when using a closed test setup for OECD 308 tests, agitation of the water phase overlaying the sediment and the test item application using low co-solvent volume is critical for maintaining an aerobic water layer.

Use of a Mobile-Assisted Telehealth Regimen to Increase Exercise in Transplant Candidates: A Home-Based Prehabilitation Pilot and Feasibility Trial.

INTRODUCTION: Physical fitness assessed by the Liver Frailty Index (LFI) and 6-minute walk test (6MWT) informs the prognosis of liver transplant candidates, although there are limited data on its reversibility after prehabilitation. On a home-based exercise trial, we aimed to improve LFI and 6MWT and to investigate trial feasibility and intervention adherence. METHODS: Liver transplant candidates with cirrhosis wore a personal activity tracker and used Exercise and Liver FITness app for 14 weeks, including a 2-week technology acclimation run-in. The 12-week intervention consisted of Exercise and Liver FITness app plus personal activity tracker and 15-/30-minute weekly calls with a physical activity coach aiming to complete ≥2 video-training sessions/week, or ≥500 step/d baseline increase for ≥8 weeks. We defined feasibility as ≥66% of subjects engaging in the intervention phase and adherence as ≥50% subjects meeting training end point. RESULTS: Thirty-one patients (61 ± 7 years, 71% female, model for end-stage liver disease 17 ± 5, ∼33% frail) consented and 21 (68%) started the intervention. In the 15 subjects who completed the study, LFI improved from 3.84 ± 0.71 to 3.47 ± 0.90 ( P = 0.03) and 6MWT from 318 ± 73 to 358 ± 64 m ( P = 0.005). Attrition reasons included death (n = 4) and surgery (n = 2). There was 57% adherence, better for videos than for walking, although daily steps significantly increased (3,508 vs baseline: 1,260) during best performance week. One adverse event was attributed to the intervention. DISCUSSION: Our clinical trial meaningfully improved LFI by 0.4 and 6MWT by 41 m and met feasibility/adherence goals. In-training daily step increase supported physical self-efficacy and intervention uptake, but maintenance remained a challenge despite counseling.

Liver transplantation: current and future.

PURPOSE: The aim of this paper is to summarize the allocation challenges facing the field of liver transplantation while providing examples of the expansion of indications for the procedure. METHODS: UNOS allocation policy was reviewed as well as the recent literature describing expanded criteria for recipient candidate selection. RESULTS: Liver allocation policy changes for deceased-donor organs remain gridlocked in legal and bureaucratic red tape. Meanwhile, the indications for liver transplantation are being expanded to include acute alcoholic hepatitis, intrahepatic cholangiocarcinoma, and colorectal metastasis, previously viewed as absolute contraindications, but under strict selection criteria. CONCLUSIONS: Attempting to meet the demand for livers, transplant centers are increasingly turning to living donor liver transplantation, protocols such as HCV-positive to HCV-negative transplants, and machine perfusion of marginal organs.

Hepatic Resection for Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of 7226 Patients.

Objective: To systematically review and compare the overall (OS) and disease-free (DFS) survival after hepatic resections for hepatocellular carcinoma (HCC) of patients with nonalcoholic fatty liver disease (NAFLD) versus other risk factors. Background: Different clinical and tumor characteristics are associated with HCC in the setting of NAFLD in comparison to other risk factors. It is still unclear whether these differences impact patient survival after radical hepatectomies. Methods: Randomized controlled trials and observational studies published in the English literature between July 1980 and June 2020 were searched using multiple databases. Patients' baseline characteristics and the hazard ratios (HRs) of the OS and DFS were extracted and meta-analyses were performed. Results: Fifteen retrospective cohort studies with a total of 7226 patients were included. Among them, 1412 patients (19.5%) had NAFLD and 5814 (80.4%) had other risk factors (eg, viral hepatitis B or C, alcoholic cirrhosis, or cryptogenic cirrhosis). Summary statistics showed that patients with NAFLD had better DFS (HR = 0.81; 95% CI: 0.70-0.94; P = 0.006) and OS (HR = 0.78; 95% CI: 0.67-0.90; P = 0.001) than the control group. Subgroups analyses also indicated that the OS favored NAFLD patients versus patients with viral hepatitis B or C (HR = 0.80; 95% CI: 0.67-0.96; P = 0.017) or alcoholic and cryptogenic cirrhosis (HR = 0.68; 95% CI: 0.47-1.0; P = 0.05). Conclusion: After hepatic resections for HCC, NAFLD patients have better DFS and OS than patients with other risk factors. Subgroup analysis and meta-regression suggested that the survival advantage of NAFLD patients was more pronounced in studies published after 2015 and from Asian centers.

HCV recurrence in HIV-infected patients after liver transplant.

Patients coinfected with hepatitis C virus (HCV) and HIV undergoing liver transplantation (LT) are at risk of early, aggressive HCV recurrence. This study investigates the use of frequent protocol-driven biopsies to identify HCV recurrence post LT in coinfected patients. Five consecutive HIV/HCV-coinfected patients underwent LT. Liver biopsies were obtained post LT at 1 hour; days 7, 120, and 365; then annually; and as clinically indicated. Stage 2 (Ishak) or higher fibrosis occurred in 4 of the 5 patients by 60, 120, 270, and 365 days. Two patients died of HCV recurrence and liver failure at 6 and 35 months post LT. Three patients survived more than 4 years after LT, 2 having sustained virologic responses to anti-HCV treatment. Another has histologic recurrence not responding to treatment. Hepatitis C virus recurrence can be rapid and aggressive after LT in HIV-coinfected patients. Serial biopsies identify recurrence early, allowing for prompt initiation of treatment.

Biodegradation testing of volatile hydrophobic chemicals in water-sediment systems - Experimental developments and challenges.

Degradation data are crucial for the persistence assessment of chemicals and they are generated using standard OECD guidelines. The OECD 308 describes a simulation biodegradation test of chemicals in water-sediment systems. This guideline is not applicable for testing highly volatile chemicals and recommends a closed biometer test setup for testing slightly volatile chemicals. However, proper details on system geometries, construction and monitoring of aerobic conditions are not provided. The choice of system geometry and sediment:water ratio influences the partitioning of test chemicals between different compartments (water, sediment and headspace) and can therefore affect their degradation. The guideline recommends the addition of test chemical via aqueous solutions, which however is not possible for hydrophobic volatile chemicals due to their volatilization losses and low solubility. Thus, the use of a co-solvent is necessary for the application of such chemicals but its effects in a closed setup has not been studied. We recently developed an improved closed test setup for testing volatile chemicals in soil. The objective was to adapt this improved test setup to conduct OECD 308 tests using 14C labelled chemicals with different volatilities. Using the adapted test setup it was possible to obtain a complete mass balance even for n-decane and tetralin having the highest Henry's constants of the tested chemicals. However, the use of co-solvent affected the oxygen levels, which in turn affected microbial activity and likely also the degradation of test chemicals. Therefore, the adapted test setup needs further developments for the testing of volatile hydrophobic chemicals.

Biodegradability assessment of complex, hydrophobic substances: Insights from gas-to-liquid (GTL) fuel and solvent testing.

The assessment of substances of Unknown or Variable composition, Complex reaction products or Biological materials (UVCBs) presents significant challenges when determining biodegradation potential and environmental persistence for regulatory purposes. An example of UVCBs is the gas-to-liquid (GTL) products, which are synthetic hydrocarbons produced from natural gas using a catalytic process known as the Fischer-Tropsch process. These synthetic hydrocarbons are fractionated into a wide array of products equivalent in function to their petroleum-derived analogues. Here we summarise the results of an extensive testing program to assess the biodegradability of several GTL products. This program highlights the challenges associated with UVCBs and provides a case study for the assessment of such substances that are also poorly soluble and volatile. When tested with the appropriate methods, all the GTL products assessed in this study were found to be readily biodegradable indicating they are not likely to be persistent in the environment.