Disrupted BMP-9 Signaling Impairs Pulmonary Vascular Integrity in Hepatopulmonary Syndrome.

RATIONALE: Hepatopulmonary syndrome (HPS) is a severe complication of liver diseases characterized by abnormal dilatation of pulmonary vessels, resulting in impaired oxygenation. Recent research highlights the pivotal role of liver-produced bone morphogenetic protein (BMP)-9 in maintaining pulmonary vascular integrity. OBJECTIVES: This study aimed to investigate the involvement of BMP-9 in human and experimental HPS. METHODS: Circulating BMP-9 levels were measured in 63 healthy controls and 203 cirrhotic patients, with or without HPS. Two animal models of portal hypertension were employed: common bile duct ligation (CBDL) with cirrhosis and long-term partial portal vein ligation (PPVL) without cirrhosis. Additionally, the therapeutic effect of low-dose BMP activator FK506 was investigated, and the pulmonary vascular phenotype of BMP-9 knockout rats was analyzed. MEASUREMENTS AND MAIN RESULTS: Patients with HPS related to compensated cirrhosis demonstrated lower levels of circulating BMP-9 compared to patients without HPS. Severe cirrhosis patients exhibited consistently low levels of BMP-9. In animal models, HPS characteristics, including intrapulmonary vascular dilations (IPVDs) and alveolo-arterial gradient enlargement, were observed. HPS development in both rat models correlated with reduced intrahepatic BMP-9 expression, decreased circulating BMP-9 level and activity, and impaired pulmonary BMP-9 endothelial pathway. Daily treatment with FK506 for 2-weeks restored BMP pathway in the lungs, alleviating IPVDs, and improving gas exchange impairment. Furthermore, BMP-9 knockout rats displayed a pulmonary HPS phenotype, supporting its role in disease progression. CONCLUSION: The study findings suggest that portal hypertension-induced loss of BMP-9 signaling contributes to HPS development.

Clinical Application of Infrared Spectroscopy in Liver Transplantation for Rapid Assessment of Lipid Content in Liver Graft.

Liver transplantation (LT) is a major treatment for patients with end-stage liver diseases. Steatosis is a significant risk factor for primary graft nonfunction and associated with poor long-term graft outcomes. Traditionally, the evaluation of steatosis is based on frozen section examination to estimate the percentage of hepatocytes containing lipid vesicles. However, this visual evaluation correlates poorly with the true lipid content. This study aimed to address the potential of infrared (IR) microspectroscopy for rapidly estimating lipid content in the context of LT and assessing its impact on survival. Clinical data were collected for >20 months from 58 patients who underwent transplantation. For each liver graft, macrovacuolar steatosis and microvesicular steatosis were evaluated through histologic examination of frozen tissue section. Triglycerides (TG) were further quantified using gas phase chromatography coupled with a flame ionization detector (GC-FID) and estimated by IR microspectroscopy. A linear relationship and significant correlation were observed between the TG measured by GC-FID and those estimated using IR microspectroscopy (R2 = 0.86). In some cases, microvesicular steatosis was related to high lipid content despite low levels of macrovacuolar steatosis. Seven patients experienced posttransplantation liver failure, including 5 deceased patients. All patients underwent transplantation with grafts containing significantly high TG levels. A concentration of 250 nmol/mg was identified as the threshold above which the risk of failure after LT significantly increased, affecting 35% of patients. Our study established a strong correlation between LT outcomes and lipid content. IR microspectroscopy proved to be a rapid and reliable approach for assessing the lipid content in clinical settings.

Identification of liver transplant biopsy phenotypes associated with distinct liver biological markers and allograft survival.

The intricate association between histologic lesions and circulating antihuman leucocyte antigen donor-specific antibodies (DSA) in liver transplantation (LT) requires further clarification. We conducted a probabilistic, unsupervised approach in a comprehensively well-annotated LT cohort to identify clinically relevant archetypes. We evaluated 490 pairs of LT biopsies with DSA testing from 325 recipients transplanted between 2010 and 2020 across 3 French centers and an external cohort of 202 biopsies from 128 recipients. Unsupervised archetypal analysis integrated all clinico-immuno-histologic parameters of each biopsy to identify biopsy archetypes. The median time after LT was 1.17 (interquartile range, 0.38-2.38) years. We identified 7 archetypes distinguished by clinico-immuno-histologic parameters: archetype #1: severe T cell-mediated rejection (15.9%); #2: chronic rejection with ductopenia (1.8%); #3: architectural and microvascular damages (3.5%); #4: (sub)normal (55.9%); #5: mild T cell-mediated rejection (4.9%); #6: acute antibody-mediated rejection (6.5%); and #7: chronic rejection with DSA (11.4%). Cell infiltrates vary in the archetype. These archetypes were associated with distinct liver biological markers and allograft outcomes. These findings remained consistent when stratified using the patient's age or indications for LT, with good performance in the external cohort (mean highest probability assignment = 0.58, standard deviation ± 0.17). In conclusion, we have identified clinically meaningful archetypes, providing valuable insights into the intricate DSA-histology association, which may help standardize liver allograft pathology classification.

Long-term outcome following liver transplantation of patients with ACLF grade 3.

BACKGROUND AND AIMS: Utility, a major principle for allocation in the context of transplantation, is questioned in patients with acute-on chronic liver failure grade 3 (ACLF-3) who undergo liver transplantation (LT). We aimed to explore long-term outcomes of patients included the three-center retrospective French experience published in 2017. METHOD: All patients with ACLF-3 (n=73) as well as their transplanted matched controlled with ACLF-2 (n=145), 1 (n=119) and no ACLF (n=292) that have participated in the princeps study published in 2017 were included. We explored 5- and 10-year patient and graft survivals, causes of death and their predictive factors. RESULTS: Median follow-up of patients ACLF-3 patients was 7.5 years. At LT, median MELD was 40. In patients with ACLF-3, 2, 1 and no ACLF, 5-year patients' survivals were respectively 72.6% vs. 69.7% vs. 76.4% vs. 77.0% (p=0.31). Ten-year patients' survival ACLF-3 was 56.8% and was not different other groups (p=0.37) Leading causes of death in ACLF-3 patients were infections (33.3%), and cardiovascular events (23.3%). After exclusion of early death, UCLA futility risk score, age-adjusted Charlson comorbidity index and Chronic Liver Failure Consortium ACLF score were independently associated with 10-year patients' survival. Long-term grafts' survivals were not different across the groups. Clinical frailty scale and WHO performance status improved over time in patients alive after 5 years. CONCLUSION: 5- and 10-year patients' and grafts' survivals in ACLF-3 patients were not different from their controls. 5-year patients' survival is higher than that of the 50%-70% threshold defining the utility of liver graft. Efforts should focus on candidates' selection based on comorbidities as well as the prevention of infection and cardiovascular events standing as the main cause of death. IMPACT AND IMPLICATIONS: While short-term outcomes following liver transplantation in the most severely ill cirrhotic patients (ACLF-3) are known, long-term data are limited, raising questions about the utility of graft allocation in the context of scarce medical resources. This study provides a favorable long-term update, confirming no differences in 5- and 10-year patient and graft survival following liver transplantation in ACLF-3 patients compared to matched ACLF-2, ACLF-1, and no-ACLF patients. The study highlights the risk of dying from infection and cardiovascular causes in the long-term and identifies scores including comorbidities evaluation, such as the age-adjusted Charlson Comorbidity Index, as independently associated with long-term survival. Therefore, physicians should consider the cumulative burden of comorbidities when deciding to transplant these patients. Additionally, after transplantation, the study encourages mitigating infectious risk with tailored immunosuppressive regimens and managing tightly cardiovascular risk over time.

Use of HBsAg-positive donors in liver transplantation: An ILTS-EASL-AASLD multisociety survey.

The gap between organ supply and demand in liver transplantation remains large in most parts of the world. One strategy to increase the donor pool is to use grafts infected with HCV, HBV, and/or HIV viruses. We aimed to explore the current use of HBsAg-positive liver grafts worldwide. A prospective cross-sectional web-based survey was designed, with a total of 28 queries, assessing national and local regulations, center experience, and center-specific experience related to the topic, and sent to all members of International Liver Transplantation Society, European Association for the Study of the Liver, and American Association for the Study of the Liver, and promoted on social media. A total of 135 liver transplant centers answered the survey: 38% from WHO European Regions, 39% from American regions, and 9.7% from South-East Asian regions. Most of the participating centers (67.3%) had been performing liver transplantation for over 15 years, with a mean of 66.5 liver transplants per year, and 54% also performed living-donor liver transplants. HBV-related disease was the indication for liver transplantation in an average of 15% of all liver transplantation cases. Regarding national and/or regional regulations, 40% of the centers reported that the use of HBsAg-positive donors was permitted, and an additional 20% could use them under special circumstances. Thirty-two centers (31%) had previously used HBsAg-positive donors. Among these centers, 62.5% conducted living-donor liver transplants and showed an increased inclination toward the use of HBsAg-positive grafts in centers with elevated waitlist mortality. HBsAg-positive donors are underutilized worldwide. The use of HBsAg-positive liver grafts could help to increase the donor pool, particularly in highly endemic areas.

An international, multicenter, survey-based analysis of practice and management of acute liver failure.

Acute liver failure (ALF) is an acute liver dysfunction with coagulopathy and HE in a patient with no known liver disease. As ALF is rare and large clinical trials are lacking, the level of evidence regarding its management is low-moderate, favoring heterogeneous clinical practice. In this international multicenter survey study, we aimed to investigate the current practice and management of patients with ALF. An online survey targeting physicians who care for patients with ALF was developed by the International Liver Transplantation Society ALF Special-Interest Group. The survey focused on the management and liver transplantation (LT) practices of ALF. Survey questions were summarized overall and by geographic region. A total of 267 physicians completed the survey, with a survey response rate of 21.36%. Centers from all continents were represented. More than 90% of physicians specialized in either transplant hepatology/surgery or anesthesiology/critical care. Two hundred fifty-two (94.4%) respondents' institutions offered LT. A total of 76.8% of respondents' centers had a dedicated liver-intensive or transplant-intensive care unit ( p < 0.001). The median time to LT was within 48 hours in 12.7% of respondents' centers, 72 hours in 35.6%, 1 week in 37.6%, and more than 1 week in 9.6% ( p < 0.001). Deceased donor liver graft (49.6%) was the most common type of graft offered. For consideration of LT, 84.8% of physicians used King's College Criteria, and 41.6% used Clichy Criteria. Significant differences were observed between Asia, Europe, and North America for offering LT, number of LTs performed, volume of patients with ALF, admission to a dedicated intensive care unit, median time to LT, type of liver graft, monitoring HE and intracranial pressure, management of coagulopathy, and utilization of different criteria for LT. In our study, we observed significant geographic differences in the practice and management of ALF. As ALF is rare, multicenter studies are valuable for identifying global practice.

Recipient age influences survival after liver transplant: Results of the French national cohort 2007-2017.

BACKGROUND: In recent years, age at liver transplantation (LT) has markedly increased. In the context of organ shortage, we investigated the impact of recipient age on post-transplantation mortality. METHODS: All adult patients who received a first LT between 2007 and 2017 were included in this cross-sectional study. Recipients' characteristics at the time of listing, donor and surgery data, post-operative complications and follow-up of vital status were retrieved from the national transplantation database. The impact of age on 5-year overall mortality post-LT was estimated using a flexible multivariable parametric model which was also used to estimate the association between age and 10-year net survival, accounting for expected age- and sex-related mortality. RESULTS: Among the 7610 patients, 21.4% were aged 60-65 years, and 15.7% over 65. With increasing age, comorbidities increased but severity of liver disease decreased. Older recipient age was associated with decreased observed survival at 5 years after LT (p < .001), with a significant effect particularly during the first 2 years. The linear increase in the risk of death associated with age does not allow any definition of an age's threshold for LT (p = .832). Other covariates associated with an increased risk of 5-year death were dialysis and mechanical ventilation at transplant, transfusion during LT, hepatocellular carcinoma and donor age. Ten-year flexible net survival analysis confirmed these results. CONCLUSION: Although there was a selection process for older recipients, increasing age at LT was associated with an increased risk of death, particularly in the first years after LT.

Liver transplant selection criteria and outcomes in critically ill patients with ACLF.

Background & Aims: Retrospective studies have reported good results with liver transplantation (LTx) for acute-on-chronic liver failure (ACLF) in selected patients. The aim of this study was to evaluate the selection process for LTx in patients with ACLF admitted to the intensive care unit (ICU) and to assess outcomes. Methods: This prospective, non-interventional, single high-volume center study collected data on patients with ACLF admitted to the ICU between 2017-2020. Results: Among 200 patients (mean age: 55.0 ± 11.2 years and 74% male), 96 patients (48%) were considered potential candidates for LTx. Unfavourable addictology criteria (n = 76) was the main reason for LTx ineligibility. Overall, 69 patients were listed for LTx (34.5%) and 50 were transplanted (25% of the whole population). The 1-year survival in the LTx group was significantly higher than in the non-transplanted group (94% vs. 15%, p <0.0001). Among patients eligible for LTx, mechanical ventilation during the first 7 days of ICU stay and an increase in the number of organ failures at day 3 were associated with the absence of LTx or death (odds ratio 9.58; 95% CI 3.29-27.89; p <0.0001 for mechanical ventilation and odds ratio 1.87; 95% CI 1.08-3.24; p <0.027 for increasing organ failures). The probability of not being transplanted in patients with ACLF under mechanical ventilation is >85.4% in those experiencing an increase of 2 organ failures since admission or >91% if experiencing an increase >2 organ failures, at which point futility could be considered. Conclusion: This prospective analysis of outcomes of patients with ACLF admitted to the ICU highlights the drastic nature of selection in this setting. Unfavourable addictology criteria, mechanical ventilation and increasing number of organ failures since admission were predictive of absence of LTx, futility and death. Impact and implications: Liver transplantation (LT) is the best therapeutic option in selected cirrhotic patients admitted to the ICU with acute on chronic liver failure. However, the selection criteria are poorly described and based on retrospective studies. This is the first prospective study that aimed to describe the selection process for LT in a transplant center. Patients with ACLF should be admitted to the ICU and evaluated within a short period of time for LT. In the context of organ shortage, eligibility for LT and either absence of LT, futility of care or death are better clarified in our study. These are mainly determined by prolonged respiratory failure and worsening of organ failures since ICU admission. Considering worldwide variations in the etiology and definition of ACLF, transplant availability and a narrow therapeutic window for transplant further prospective studies are awaited.