The challenges and potential of microRNA-based therapy for patients with liver failure syndromes and hepatocellular carcinoma.

INTRODUCTION: Morbidity and mortality from liver disease continues to rise worldwide. There are currently limited curative treatments for patients with liver failure syndromes, encompassing acute liver failure and decompensated cirrhosis states, outside of transplantation. Whilst there have been improvements in therapeutic options for patients with hepatocellular carcinoma (HCC), there remain challenges necessitating novel therapeutic agents. microRNA have long been seen as potential therapeutic targets but there has been limited clinical translation. AREAS COVERED: We will discuss the limitations of conventional non-transplant management of patients with liver failure syndromes and HCC. We will provide an overview of microRNA and the challenges in developing and delivering microRNA-based therapeutic agents. We will finally provide an overview of microRNA-based therapeutic agents which have progressed to clinical trials. EXPERT OPINION: microRNA have great potential to be developed into therapeutic agents due to their association with critical biological processes which govern health and disease. Utilizing microRNA sponges to target multiple microRNA associated with specific biological processes may improve their therapeutic efficacy. However, there needs to be significant improvements in delivery systems to ensure the safe delivery of microRNA to target sites and minimize systemic distribution. This currently significantly impacts the clinical translation of microRNA-based therapeutic agents.

The challenges and potential in developing microRNA associated with regeneration as biomarkers to improve prognostication for liver failure syndromes and hepatocellular carcinoma.

INTRODUCTION: Determining the need for liver transplantation remains critical in the management of hepatocellular carcinoma (HCC) and liver failure syndromes (including acute liver failure and decompensated cirrhosis states). Conventional prognostic models utilize biomarkers of liver and non-liver failure and have limitations in their application. Novel biomarkers which predict regeneration may fulfil this niche. microRNA are implicated in health and disease and are present in abundance in the circulation. Despite this, they have not translated into mainstream clinical biomarkers. AREAS COVERED: We will discuss current challenges in the prognostication of patients with liver failure syndromes as well as for patients with HCC. We will discuss biomarkers implicated with liver regeneration. We then provide an overview of the challenges in developing microRNA into clinically tractable biomarkers. Finally, we will provide a scoping review of microRNA which may have potential as prognostic biomarkers in liver failure syndromes and HCC. EXPERT OPINION: Novel biomarkers are needed to improve prognostic models in liver failure syndromes and HCC. Biomarkers associated with liver regeneration are currently lacking and may fulfil this niche. microRNA have the potential to be developed into clinically tractable biomarkers but a consensus on standardizing methodology and reporting is required prior to large-scale studies.

The positive impact of the COVID 19 pandemic on organ utilisation in liver transplantation.

Background: As the world recovers from the aftermath of devastating waves of an outbreak, the ongoing Coronavirus disease 2019 pandemic has presented a unique perspective to the transplantation community of ''organ utilisation'' in liver transplantation, a poorly defined term and ongoing hurdle in this field. To this end, we report the key metrics of transplantation activity from a high-volume liver transplantation centre in the United Kingdom over the past two years. Methods: Between March 2019 and February 2021, details of donor liver offers received by our centre from National Health Service Blood & Transplant, and of transplantation were reviewed. Differences in the activity before and after the outbreak of the pandemic, including short term post-transplant survival, have been reported. Results: The pandemic year at our centre witnessed a higher utilisation of Donation after Cardiac Death livers (80.4% vs. 58.3%, p = 0.016) with preserved United Kingdom donor liver indices and median donor age (2.12 vs. 2.02, p = 0.638; 55 vs. 57 years, p = 0.541) when compared to the pre-pandemic year. The 1- year patient survival rates for recipients in both the periods were comparable. The pandemic year, that was associated with increased utilisation of Donation after Cardiac Death livers, had an ischaemic cholangiopathy rate of 6%. Conclusions: The pressures imposed by the pandemic led to increased utilisation of specific donor livers to meet patient needs and minimise the risk of death on the waiting list, with apparently preserved early post-transplant survival. Optimum organ utilisation is a balancing act between risk and benefit for the potential recipient, and technologies like machine perfusion may allow surgeons to increase utilisation without compromising patient outcomes.

Satellite liver transplant centres significantly improve transplant assessment outcomes for patients with chronic liver disease but not hepatocellular carcinoma: a retrospective cohort study.

Introduction: Liver transplantation (LT) remains integral to the management of end-stage chronic liver disease (CLD). However, referral thresholds and assessment pathways remain poorly defined. Distance from LT centre has been demonstrated to impact negatively on patient outcomes resulting in the development of satellite LT centres (SLTCs). We aimed to evaluate the impact of SLTCs on LT assessment in patients with CLD and hepatocellular carcinoma (HCC). Methods: A retrospective cohort study was undertaken including all patients with CLD or HCC assessed for LT at King's College Hospital (KCH) between October 2014 and October 2019. Referral location, social, demographic, clinical and laboratory data were collected. Univariable and multivariable analyses (MVA) were performed to assess the impact of SLTCs on patients being accepted as LT candidates and contraindications being identified. Results: 1102 and 240 LT assessments were included for patients with CLD and HCC, respectively. MVA demonstrated significant associations with; patients living greater than 60 min from KCH/SLTCs and LT candidacy acceptance in CLD, and less deprived patients and LT candidacy acceptance in HCC. However, neither variable was associated with identification of LT contraindications. MVA demonstrated that referrals from SLTCs were more likely to result in acceptance of LT candidacy and less likely to result in a contraindication being identified in CLD. However, such associations were not demonstrated in HCC. Conclusion: SLTCs improve LT assessment outcomes in CLD but not HCC reflecting the standardised HCC referral pathway. Developing a formal regional LT assessment pathway across the UK would improve equity of access to transplantation.

The optimal immunosuppression management to prevent early rejection after liver transplantation: A systematic review of the literature and expert panel recommendations.

BACKGROUND: The optimal immunosuppression protocol to prevent early acute cellular rejection (ACR) after liver transplantation (LT) avoiding prolonged hospitalization and early hospital readmission is undefined. OBJECTIVES: To identify the most suitable immunosuppression regimen for inclusion in ERAS programs in order to minimize early ACR after LT and to provide expert panel recommendations DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Studies from January 2000 onward focusing on early ACR were included. Rates of early renal dysfunction and infection were evaluated. CRD42021245586 RESULTS: Thirty-seven studies met inclusion criteria; 23 randomized controlled trials, 14 retrospective or prospective observational comparative or noncomparative studies. Several sources of biases which potentially confound conclusions were identified: heterogeneity in immunosuppression protocols, higher serum tacrolimus levels than currently used in clinical practice, differences in the definition of ACR. CONCLUSIONS: Tacrolimus is the standard immunosuppression after LT and can be used in combination with other drugs such as corticosteroids and MMF, and in association with anti-IL2 receptor antibody (IL2Ra) induction. (Quality of Evidence; Low | Grade of Recommendation; Strong). Low dose or delayed introduction of tacrolimus in association with corticosteroids and MMF and/or anti-IL2Ra induction can be used to reduce acute kidney injury. (Quality of Evidence; Low | Grade of Recommendation; Strong). Use of tacrolimus in association with corticosteroids and MMF and/or anti-IL2Ra induction does not lead to increased infection rates. (Quality of Evidence; Low | Grade of Recommendation; Weak).

Liver transplantation for HCC: validation of prognostic power of the RETREAT score for recurrence in a UK cohort.

BACKGROUND: The Risk Estimation of Tumor Recurrence After Transplant (RETREAT) score as a prognostic index for recurrence has been reported previously and has not been validated outside the USA. Our study has validated the score in a single center UK cohort of patients being transplanted for HCC. METHODS: LT for HCC between 2008 and 2018 at our center were analyzed. Recurrence-free survival (RFS) was compared by the RETREAT score and validated using Net Reclassification Improvement (NRI) by comparing it to Milan criteria. RESULTS: 346 adult HCC patients were transplanted of whom 313 were included. 28 (8.9%) had a recurrence. Summation of largest diameter and total number of viable tumors (HR = 1.19, p < 0.001), micro-/macro-vascular invasion (HR = 3.74, p = 0.002) and AFP>20 ng/ml (HR = 3.03, p = 0.005) were associated with recurrence on multivariate analysis. RFS decreased with increasing RETREAT score (log-rank p = 0.016). RETREAT performed better than Milan with significant NRI at 1- and 2-years post-transplant (0.43 (p = 0.004) and 0.38 (p = 0.03) respectively). CONCLUSION: LT outcomes using the revised UK criteria are equivalent to Milan criteria. Further, RETREAT score was validated as a prognostic index for the first time in a UK cohort and may assist risk stratification, selection for adjuvant therapies and guide surveillance.

Regeneration linked miRNA modify tumor phenotype and can enforce multi-lineage growth arrest in vivo.

Regulated cell proliferation is an effector mechanism of regeneration, whilst dysregulated cell proliferation is a feature of cancer. We have previously identified microRNA (miRNA) that regulate successful and failed human liver regeneration. We hypothesized that these regulators may directly modify tumor behavior. Here we show that inhibition of miRNAs -503 and -23a, alone or in combination, enhances tumor proliferation in hepatocyte and non-hepatocyte derived cancers in vitro, driving more aggressive tumor behavior in vivo. Inhibition of miRNA-152 caused induction of DNMT1, site-specific methylation with associated changes in gene expression and in vitro and in vivo growth inhibition. Enforced changes in expression of two miRNA recapitulating changes observed in failed regeneration led to complete growth inhibition of multi-lineage cancers in vivo. Our results indicate that regulation of regeneration and tumor aggressiveness are concordant and that miRNA-based inhibitors of regeneration may constitute a novel treatment strategy for human cancers.

A novel microRNA-based prognostic model outperforms standard prognostic models in patients with acetaminophen-induced acute liver failure.

BACKGROUND & AIMS: Acetaminophen (APAP)-induced acute liver failure (ALF) remains the most common cause of ALF in the Western world. Conventional prognostic models, utilising markers of liver injury and organ failure, lack sensitivity for mortality prediction. We previously identified a microRNA signature that is associated with successful regeneration post-auxiliary liver transplant and with recovery from APAP-ALF. Herein, we aimed to use this microRNA signature to develop outcome prediction models for APAP-ALF. METHODS: We undertook a nested, case-control study using serum samples from 194 patients with APAP-ALF enrolled in the US ALF Study Group registry (1998-2014) at early (day 1-2) and late (day 3-5) time-points. A microRNA qPCR panel of 22 microRNAs was utilised to assess microRNA expression at both time-points. Multiple logistic regression was used to develop models which were compared to conventional prognostic models using the DeLong method. RESULTS: Individual microRNAs confer limited prognostic value when utilised in isolation. However, incorporating them within microRNA-based outcome prediction models increases their clinical utility. Our early time-point model (AUC = 0.78, 95% CI 0.71-0.84) contained a microRNA signature associated with liver regeneration and our late time-point model (AUC = 0.83, 95% CI 0.76-0.89) contained a microRNA signature associated with cell-death. Both models were enhanced when combined with model for end-stage liver disease (MELD) score and vasopressor use and both outperformed the King's College criteria. The early time-point model combined with clinical parameters outperformed the ALF Study Group prognostic index and the MELD score. CONCLUSIONS: Our findings demonstrate that a regeneration-linked microRNA signature combined with readily available clinical parameters can outperform existing prognostic models for ALF in identifying patients with poor prognosis who may benefit from transplantation. LAY SUMMARY: While acute liver failure can be reversible, some patients will die without a liver transplant. We show that blood test markers that measure the potential for liver recovery may help improve identification of patients unlikely to survive acute liver failure who may benefit from a liver transplant.

Validation of a Capillary Dry Blood Sample MITRA-Based Assay for the Quantitative Determination of Systemic Tacrolimus Concentrations in Transplant Recipients.

BACKGROUND: Tacrolimus is a narrow therapeutic index medication, which requires therapeutic drug monitoring to optimize dosing based on systemic exposure. MITRA microsampling offers a convenient, minimally invasive approach for the collection of capillary blood samples from a finger prick versus conventional venous blood sampling for quantitation of tacrolimus blood concentrations. However, the suitability of MITRA microsampling for the determination of tacrolimus concentrations requires assessment in clinical settings. METHODS: Paired venous (2 mL) and capillary (10 µL) blood samples were collected pre-tacrolimus dose and 1 and 3 hours postdose during routine outpatient visits from stable adult liver or kidney transplant patients receiving prolonged-release tacrolimus. Tacrolimus concentrations were determined by liquid chromatography-tandem mass spectrometry, and the concentrations obtained by the 2 sampling methods were compared by linear regression and Bland-Altman agreement analyses. RESULTS: Samples were available for 82 transplant recipients (kidney, n = 41; liver, n = 41). A high correlation was observed between tacrolimus concentrations in capillary and venous blood samples (Pearson correlation coefficient, 0.97; Lin concordance coefficient, 0.87; slope of the fitted line, >1.0). Tacrolimus concentrations in capillary samples were 22.5% higher on average than in the corresponding venous blood samples (95% limits of agreement, 0.5%-44.6%). Similar results were observed in both transplant subgroups. CONCLUSIONS: MITRA finger prick sampling provides a convenient alternative to venipuncture for therapeutic drug monitoring in transplant recipients maintained on prolonged-release tacrolimus. When using the finger prick MITRA method, the positive bias in tacrolimus concentrations observed with this technique, when compared with venipuncture, needs to be taken into consideration.

Risk-adjusted survival in liver transplant patients assessed and managed by a non-transplanting centre: South West Liver Unit experience.

BACKGROUND: Liver transplant services remain a scarce resource not reflective of geography or burden of liver disease within the UK. To address geographical concerns in the South West (SW), a devolved network model of care for liver transplantation was established in 2004 between the SW Liver Unit (SWLU) at Derriford Hospital, Plymouth and King's College Hospital, London. The SWLU has evolved to deliver both pre-transplant and post-transplant care for patients across the SW Peninsula. We determined whether risk-adjusted survival in patients assessed and managed at the SWLU compared with existing UK transplant centres. DESIGN: Retrospective analysis of records at National Health Service Blood and Transplant (NHSBT) for patients ≥18 years listed or undergoing first liver only deceased donor transplantation from 1 January 2006 to 31 December 2017. Data collected and used were in accordance with standard NHSBT outcome measures. RESULTS: We identified 8492 patients registered for first liver only transplant and 6140 patients who subsequently underwent transplantation. Of these, 215 patients listed and 172 patients transplanted were registered at the SWLU. The 1-year, 5-year and 10-year risk-adjusted post-listing survival for patients registered at the SWLU were 86%, 75% and 67%, respectively, with 1-year and 5-year risk-adjusted post-transplant survival 94.9% and 84.4%, respectively. CONCLUSIONS: Risk-adjusted post-listing 1-year, 5-year and 10-year survival outcomes and risk-adjusted 1-year and 5-year post-transplant survival outcomes at the SWLU are good and comparable with the seven UK transplant centres. These outcomes provide assurance that care delivered by our regional programme is equivalent to well-established liver transplant programmes.

Serum MicroRNA Signatures in Recovery From Acute and Chronic Liver Injury and Selection for Liver Transplantation.

We previously demonstrated a distinct hepatic microRNA (miRNA) signature (down-regulation of miRNA-23a, -150, - 200b, -503, and -663 and up-regulation of miRNA-20a) is associated with successful regeneration in auxiliary liver transplantation (ALT). This study aimed to evaluate whether the serum expression of this regeneration-linked miRNA signature is associated with clinical outcomes in acute and chronic liver disease. These were represented by patients with acetaminophen-induced acute liver failure (ALF; n = 18) and patients with hepatitis C virus (HCV) undergoing treatment with direct-acting antivirals (n = 56), respectively. Patients were grouped depending on their clinical outcome. Global serum miRNA expression was analyzed using polymerase chain reaction (PCR) arrays and selected miRNA expression using targeted PCR. We demonstrate that specific regeneration-linked miRNAs discriminate outcomes in both clinical scenarios. We further show that miRNA-20a, -23a, -150, -200b, -503, and -663 undergo concordant changes in expression in 3 distinct clinical settings: liver regeneration accompanying successful ALT, clinical recovery after ALF, and clinical recompensation after cure of HCV. This miRNA signature represents a potentially novel biomarker to predict outcome and optimize patient selection for liver transplantation in both acute and chronic liver disease.

Sequential Cohort Analysis After Liver Transplantation Shows de Novo Extended Release Tacrolimus Is Safe, Efficacious, and Minimizes Renal Dysfunction.

The use of once-daily extended-release tacrolimus (ERT) is associated with improved long-term graft and patient survival when compared with twice-daily tacrolimus (BDT), but the underlying reasons for differential survival are unclear. The aim of the study was to compare clinical outcomes known to impact on posttransplant survival for de novo BDT and ERT in liver transplantation (LT) recipients. METHODS: We conducted a single-center, prospective sequential cohort analysis of adult patients undergoing LT during a change in protocol from de novo BDT to ERT, with a 6-month post-LT follow-up. RESULTS: A total of 160 transplanted patients were evaluated; 82 were in the BDT group and 78 were in the ERT group. The cohorts were matched for standard variables and a similar proportion in each group received induction interleukin-2 receptor antibody (36% and 31%). There were no significant differences in the measured outcomes of patient and graft survival, biopsy-proven acute rejection episodes, post LT diabetes, and toxicity. A significantly lower number of patients developed chronic kidney disease Stage3-4 in the ERT cohort compared with BDT cohort. In patients with pre-LT renal dysfunction who received antibody induction, estimated glomerular filtration rate decreased significantly in the BDT but not the ERT group. CONCLUSIONS: We show that once-daily ERT is as safe and efficacious as BDT in de novo LT but optimally conserves renal function post-LT.