Management of Biliary Complications in Liver Transplant Recipients

Detection of inflammasome activation in liver tissue during the donation process as potential biomarker for liver transplantation

Deceased donor liver transplantation (LT) is a crucial lifesaving option for patients with end-stage liver diseases. Although donation after brain death (DBD) remains the main source of donated organs, exploration of donation after circulatory death (DCD) addresses donor scarcity but introduces challenges due to warm ischemia. While technical advances have improved outcomes, challenges persist, with a 13% mortality rate within the first year. Delving into liver transplantation complexities reveals the profound impact of molecular signaling on organ fate. NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation play a pivotal role, influencing inflammatory responses. The NLRP3 inflammasome, found in hepatocytes, contributes to inflammation, fibrosis, and liver cell death. This study explores these dynamics, shedding light on potential biomarkers and therapeutic targets. Samples from 36 liver transplant patients were analyzed for ASC specks detection and inflammasome-related gene expression. Liver biopsies, obtained before and after cold ischemia storage, were processed for immunofluorescence, qRT-PCR, and Western blot. One year post-LT clinical follow-up included diagnostic procedures for complications, and global survival was assessed. Immunofluorescence detected activated inflammasome complexes in fixed liver tissues. ASC specks were identified in hepatocytes, showing a trend toward more specks in DCD livers. Likewise, inflammasome-related gene expression analysis indicated higher expression in DCD livers, decreasing after cold ischemia. Similar results were found at protein level. Patients with increased ASC specks staining exhibited lower overall survival rates, correlating with IL1B expression after cold ischemia. Although preliminary, these findings offer novel insights into utilizing direct detection of inflammasome activation in liver tissue as a biomarker. They suggest its potential impact on post-transplant outcomes, potentially paving the way for improved diagnostic approaches and personalized treatment strategies in LT.

Cell-specific Extracellular Vesicles and Their miRNA Cargo Released Into the Organ Preservation Solution During Cold Ischemia Storage as Biomarkers for Liver Transplant Outcomes

BACKGROUND

Liver transplantation (LT) is crucial for end-stage liver disease patients, but organ shortages persist. Donation after circulatory death (DCD) aims to broaden the donor pool but presents challenges. Complications like acute rejection, hepatic artery thrombosis, and biliary issues still impact posttransplant prognosis. Biomarkers, including extracellular vesicles (EVs) and microRNAs (miRNAs), show promise in understanding and monitoring posttransplant events. This study explores the role of EVs and their miRNA cargo in LT, including their potential as diagnostic tools.

METHODS

EVs from intrahepatic end-ischemic organ preservation solution (eiOPS) in 79 donated livers were detected using different techniques (nanosight tracking analysis, transmission electron microscopy, and flow cytometry). EV-derived miRNAs were identified by quantitative real time-polymerase chain reaction. Bioinformatics analysis was performed using the R platform.

RESULTS

Different-sized and origin-specific EVs were found in eiOPS, with significantly higher concentrations in DCD compared with donation after brain death organs. Additionally, several EV-associated miRNAs, including let-7d-5p, miR-28-5p, miR-200a-3p, miR-200b-3p, miR-200c-3p, and miR-429, were overexpressed in DCD-derived eiOPS. These miRNAs also exhibited differential expression patterns in liver tissue biopsies. Pathway analysis revealed enrichment in signaling pathways involved in extracellular matrix organization and various cellular processes. Moreover, specific EVs and miRNAs correlated with clinical outcomes, including survival and early allograft dysfunction. A predictive model combining biomarkers and clinical variables showed promise in acute rejection detection after LT.

CONCLUSIONS

These findings provide new insights into the use of EVs and miRNAs as biomarkers and their possible influence on posttransplantation outcomes, potentially contributing to improved diagnostic approaches and personalized treatment strategies in LT.

Number of Local Regional Therapies for Hepatocellular Carcinoma and Peri-Operative Outcomes after Liver Transplantation

The wait times for patients with hepatocellular carcinoma (HCC) listed for liver transplant are longer than ever, which has led to an increased reliance on the use of pre-operative LRTs. The impact that multiple rounds of LRTs have on peri-operative outcomes following transplant is unknown. This was a retrospective single center analysis of 298 consecutive patients with HCC who underwent liver transplant (January 2017 to May 2021). The data was obtained from two institution-specific databases and the TransQIP database. Of the 298 patients, 27 (9.1%) underwent no LRTs, 156 (52.4%) underwent 1-2 LRTs, and 115 (38.6%) underwent ≥3 LRTs prior to LT. The patients with ≥3 LRTs had a significantly higher rate of bile leak compared to patients who received 1-2 LRTs (7.0 vs. 1.3%, p = 0.014). Unadjusted and adjusted regression analyses demonstrated a significant association between the total number of LRTs administered and bile leak, but not rates of overall biliary complications. The total number of LRTs was not significantly associated with any other peri-operative or post-operative outcome measure. These findings support the aggressive use of LRTs to control HCC in patients awaiting liver transplant, with further evaluation needed to confirm the biliary leak findings.

Interventional endoscopy for abdominal transplant patients

Interventional endoscopy can play a significant role in the care and management of children pre-and post- abdominal solid organ transplantation. Such procedures primarily include endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound (EUS), and balloon-assisted enteroscopy (BAE), though additional interventions are available using standard endoscopes (gastroscopes, colonoscopes) for therapeutics purposes such as endoscopic hemostasis. The availability of pediatric practitioners with the advanced training to effectively and safely perform these procedures are most often limited to large tertiary care pediatric centers. These centers possess the necessary resources and ancillary staff to provide the comprehensive multi-disciplinary care needed for these complex patients. In this review, we discuss the importance of interventional endoscopy in caring for transplant patients, during their clinical course preceding the potential need for solid organ transplantation and inclusion of a discussion related to endoscopic post-surgical complication management. Given the highly important role of interventional endoscopy in patients with recurrent and chronic pancreatitis, we also include a discussion related to this complex disease process leading up to those patients that may need pancreas surgery including total pancreatectomy with islet autotransplantation (TPIAT).