Graft-derived cfDNA Monitoring in Plasma and Bile During Normothermic Machine Perfusion in Liver Transplantation Is Feasible and a Potential Tool for Assessing Graft Viability.

BACKGROUND: Ex vivo normothermic machine perfusion (NMP) is an organ preservation technique that enables an extended assessment of graft suitability before liver transplantation (LT). Established monitoring protocols used during NMP vary significantly in their assessment of transplant suitability when applied to the same grafts. Graft-derived cell-free DNA (gdcfDNA) analysis is an emerging tool for monitoring graft health post-transplantation. We investigated the feasibility of monitoring gdcfDNA during NMP for LT in a proof-of-concept, observational study. METHODS: Serial plasma and bile samples were collected during NMP for 10 consecutive grafts, at 15 min post-machine reperfusion and then 2-h intervals. Digital polymerase chain reaction was used to quantify gdcfDNA at each time point. RESULTS: Five grafts were suitable for LT, there were no cases of primary nonfunction or death in the recipients. gdcfDNA was quantified in all bile and plasma samples (n > 100). In plasma, gdcfDNA concentrations climbed post-machine reperfusion until 4.25 h (median 2.25 h = 15.98 × 10 6 copies/mL, 4.25 h = 40.21 × 10 6 copies/mL). gdcfDNA levels then diverged significantly when comparing the viable and non-viable graft groups (6.25 h, median viable: 117.15 × 10 6 copies/mL versus non-viable: 16.72 × 10 6 copies/mL, P = 0.01). These opposing trends correlated in each graft and in all cases with the viable/non-viable outcome. There was a trend of gradual decline in bile gdcfDNA from viable grafts post-machine reperfusion; discarded grafts showed more variable patterns of release. CONCLUSIONS: gdcfDNA analysis during NMP is a feasible and potential tool to inform viability assessment during NMP for LT. Bile gdcfDNA monitoring offers the prospect of an objective means to assess the degree of biliary injury associated with organ procurement.

Graft-Derived Cell-Free DNA Quantification following Liver Transplantation Using Tissue-Specific DNA Methylation and Donor-Specific Genotyping Techniques: An Orthogonal Comparison Study.

Background: Graft-derived cell-free DNA (gdcfDNA) analysis has shown promise as a non-invasive tool for monitoring organ health following solid organ transplantation. A number of gdcfDNA analysis techniques have been described; however, the majority rely on sequencing or prior genotyping to detect donor-recipient mis-matched genetic polymorphisms. Differentially methylated regions of DNA can be used to identify the tissue-of-origin of cell-free DNA (cfDNA) fragments. In this study, we aimed to directly compare the performance of gdcfDNA monitoring using graft-specific DNA methylation analysis and donor-recipient genotyping techniques in a pilot cohort of clinical samples from patients post-liver transplantation. Results: 7 patients were recruited prior to LT, 3 developed early, biopsy-proven TCMR in the first 6 weeks post-LT. gdcfDNA was successfully quantified in all samples using both approaches. There was a high level of technical correlation between results using the two techniques (Spearman testing, rs = 0.87, p < 0.0001). gdcfDNA levels quantified using the genotyping approach were significantly greater across all timepoints in comparison to the tissue-specific DNA methylation-based approach: e.g., day 1 post-LT median 31,350 copies/mL (IQR 6731-64,058) vs. 4133 copies/mL (IQR 1100-8422), respectively. Qualitative trends in gdcfDNA levels for each patient were concordant between the two assays. Acute TCMR was preceded by significant elevations in gdcfDNA as quantified by both techniques. Elevations in gdcfDNA, using both techniques, were suggestive of TCMR in this pilot study with a 6- and 3-day lead-time prior to histological diagnosis in patients 1 and 2. Conclusions: Both the graft-specific methylation and genotyping techniques successfully quantified gdcfDNA in patients post-LT with statistically significant concordance. A direct comparison of these two techniques is not only important from a technical perspective for orthogonal validation, but significantly adds weight to the evidence that gdcfDNA monitoring reflects the underlying biology. Both techniques identified LT recipients who developed acute TCMR, with several days lead-time in comparison to conventional diagnostic workflows. Whilst the two assays performed comparably, gdcfDNA monitoring based on graft-specific DNA methylation patterns in cfDNA offers major practical advantages over the donor-recipient genotyping, and hence enhances the potential to translate this emerging technology into clinical practice.

Donor-specific cell-free DNA as a biomarker in liver transplantation: A review.

Due to advances in modern medicine, liver transplantation has revolutionised the prognosis of many previously incurable liver diseases. This progress has largely been due to advances in immunosuppressant therapy. However, despite the judicious use of immunosuppression, many liver transplant recipients still experience complications such as rejection, which necessitates diagnosis via invasive liver biopsy. There is a clear need for novel, minimally-invasive tests to optimise immunosuppression and improve patient outcomes. An emerging biomarker in this ''precision medicine'' liver transplantation field is that of donor-specific cell free DNA. In this review, we detail the background and methods of detecting this biomarker, examine its utility in liver transplantation and discuss future research directions that may be most impactful.

Case of nivolumab-induced sclerosing cholangitis: lessons from long-term follow-up.

Nivolumab is an immune checkpoint inhibitor used to treat multiple solid-organ malignancies. While many of its immune-related adverse events are well established, nivolumab-induced sclerosing cholangitis remains poorly characterised, with no defined diagnostic criteria. Moreover, data regarding long-term outcomes are particularly lacking. We present a biopsy-proven case of nivolumab-induced sclerosing cholangitis, which uniquely captures 18 months of follow-up post-treatment. Our case highlights key features of intrahepatic subtype sclerosing cholangitis and suggests durable response to corticosteroid therapy.

Epidemiology and outcomes of acute liver failure in Australia.

BACKGROUND: Acute liver failure (ALF) is a life-threatening syndrome with varying aetiologies requiring complex care and multidisciplinary management. Its changing incidence, aetiology and outcomes over the last 16 years in the Australian context remain uncertain. AIM: To describe the changing incidence, aetiology and outcomes of ALF in South Eastern Australia. METHODS: The database of the Victorian Liver Transplant Unit was interrogated to identify all cases of ALF in adults (> 16 years) in adults hospitalised between January 2002 and December 2017. Overall, 169 patients meeting criteria for ALF were identified. Demographics, aetiology of ALF, rates of transplantation and outcomes were collected for all patients. Transplant free survival and overall survival (OS) were assessed based on survival to discharge from hospital. Results were compared to data from a historical cohort from the same unit from 1988-2001. RESULTS: Paracetamol was the most common aetiology of acute liver failure, accounting for 50% of cases, with an increased incidence compared with the historical cohort (P = 0.046). Viral hepatitis and non-paracetamol drug or toxin induced liver injury accounted for 15% and 10% of cases respectively. Transplant free survival (TFS) improved significantly compared to the historical cohort (52% vs 38%, P = 0.032). TFS was highest in paracetamol toxicity with spontaneous recovery in 72% of cases compared to 31% of non-paracetamol ALF (P < 0.001). Fifty-nine patients were waitlisted for emergency liver transplantation. Nine of these died while waiting for an organ to become available. Forty-two patients (25%) underwent emergency liver transplantation with a 1, 3 and 5 year survival of 81%, 78% and 72% respectively. CONCLUSION: Paracetamol toxicity is the most common aetiology of ALF in South-Eastern Australia with a rising incidence over 30 years. TFS has improved, however it remains low in non-paracetamol ALF.

Continuous terlipressin infusion is associated with improved diet intake and muscle strength in patients awaiting liver transplant.

BACKGROUND & AIMS: Portal hypertension contributes to the pathogenesis of malnutrition and sarcopenia in cirrhosis via multiple mechanisms. Terlipressin is a vasopressin analogue that we administer via continuous outpatient infusion, as a bridge to transplantation in patients with hepatorenal syndrome or refractory ascites. We describe, for the first time, the impact of outpatient terlipressin on nutritional and muscle parameters. METHODS: Nutrition (subjective global assessment), handgrip strength, dietary intake (energy, protein), frequency of paracentesis and severity of liver disease (model for end-stage liver disease score) were prospectively recorded at terlipressin commencement and follow-up (transplantation, cessation or census date). RESULTS: Nineteen patients were included (89% male, median age 59.6 years, median model for end-stage liver disease score 24), of whom 12 had hepatorenal syndrome and 7 had refractory ascites. All patients were malnourished at baseline, 63% (n = 12) had sarcopenic-range grip strength, and mean paracentesis frequency was 2.86 ± 1.62/month. Median duration of terlipressin was 51 days (interquartile range 29-222). Fourteen patients (74%) were transplanted, 2 delisted (10%) and 3 (16%) continued terlipressin. Energy and protein intake improved significantly following terlipressin, from 17.94 ± 5.43 kcal/kg to 27.70 ± 7.48 kcal/kg, and 0.74 ± 0.28 g/kg to 1.16 ± 0.31 g/kg, respectively (both p < 0.001). Handgrip strength increased from 25.36 ± 8.13 kg to 28.49 ± 7.63 kg (p = 0.001). Linear regression analysis demonstrated hand grip strength increased 0.075% for every 1-day of terlipressin (p = 0.005). The frequency of large-volume paracentesis reduced by 46%, to 1.57 ± 1.51/month (p = 0.001). CONCLUSION: Continuous terlipressin infusion reduces the complications of portal hypertension and is associated with an improvement in nutritional and muscle parameters in patients on the liver transplant waiting list, in whom such characteristics usually demonstrate progressive decline. This validates both the aetiological role of portal hypertension in malnutrition and represents a promising new anabolic therapy. LAY SUMMARY: Malnutrition and poor muscle strength are common in liver disease and often get worse while patients await liver transplant. Terlipressin is a medication used to treat portal hypertension in patients with hepatorenal syndrome. It is usually given for a few days or weeks in patients confined to hospital. Our centre provides outpatient terlipressin for weeks to months as a bridge to liver transplant. In patients treated with terlipressin at our hospital, we observed a substantial increase in their dietary intake and muscle strength, which may improve their quality of life and outcomes after liver transplant.