Mechanism and endoscopic-treatment-induced evolution of biliary non-anastomotic stricture after liver transplantation revealed by single-cell RNA sequencing.

BACKGROUND: Biliary complications, especially non-anastomotic stricture (NAS), are the main complications after liver transplantation. Insufficient sampling and no recognized animal models obstruct the investigation. Thus, the mechanisms and alterations that occur during endoscopic treatment (ET) of NAS remain unclear. METHODS: Samples were obtained with endoscopic forceps from the hilar bile ducts of NAS patients receiving continuous biliary stent implantation after diagnosis. Retrospective analysis of multiple studies indicated that the duration of ET for NAS was approximately 1-2 years. Thus, we divided the patients into short-term treatment (STT) and long-term treatment (LTT) groups based on durations of less or more than 1 year. Samples were subjected to single-cell RNA sequencing. Transcriptomic differences between STT and normal groups were defined as the NAS mechanism. Similarly, alterations from STT to LTT groups were regarded as endoscopic-treatment-induced evolution. RESULTS: In NAS, inflammation and immune-related pathways were upregulated in different cell types, with nonimmune cells showing hypoxia pathway upregulation and immune cells showing ATP metabolism pathway upregulation, indicating heterogeneity. We confirmed a reduction in bile acid metabolism-related SPP1+ epithelial cells in NAS. Increases in proinflammatory and profibrotic fibroblast subclusters indicated fibrotic progression in NAS. Furthermore, immune disorders in NAS were exacerbated by an increase in plasma cells and dysfunction of NK and NKT cells. ET downregulated multicellular immune and inflammatory responses and restored epithelial and endothelial cell proportions. CONCLUSIONS: This study reveals the pathophysiological and genetic mechanisms and evolution of NAS induced by ET, thereby providing preventive and therapeutic insights into NAS. HIGHLIGHTS: For the first time, single-cell transcriptome sequencing was performed on the bile ducts of patients with biliary complications. scRNA-seq analysis revealed distinct changes in the proportion and phenotype of multiple cell types during Nonanastomotic stricture (NAS) and endoscopic treatment. A reduction in bile acid metabolism-related SPP1+ epithelial cells and VEGFA+ endothelial cells, along with explosive infiltration of plasma cells and dysfunction of T and NK cells in NAS patients. SPP1+ macrophages and BST2+ T cells might serve as a surrogate marker for predicting endoscopic treatment.

Adequate cumulative exposure to tacrolimus and low tacrolimus variability decrease the incidence of biliary complications after liver transplantation.

BACKGROUND: Nonearly biliary complications (BCs) after liver transplantation (LT) are highly associated with immunological status. Tacrolimus is the main immunosuppressant. Whether and how tacrolimus bioavailability affects BCs is unclear. METHODS: LT recipients receiving tacrolimus-free immunosuppressants or developing BCs within 3 months after LT were excluded. Tacrolimus-related variables included trough concentration (C0), variability and cumulative exposure to tacrolimus (CET). Receiver operating characteristic (ROC) curves defined cutoff values of CET and variability. The values divided patients into adequate and low CET groups, also high and low-variability groups. Inverse probability of treatment weighting (IPTW) was used to reduce bias. Logistic regression identified risk factors. Kaplan-Meier curves were generated for survival comparison. RESULTS: 409 patients were enrolled, and 39 (9.5 %) suffered from BCs. The mean C0 values were 6.9 and 7.2 ng/mL in the BCs and BCs-free groups, respectively. CET within 3 postoperative months was 550.0 and 608.6 ng.day/mL, while the tacrolimus variability was 0.4 and 0.3, respectively. The cutoff values for CET within 3 months and variability predicting BCs were 660.5 and 0.54, respectively. Multivariable logistic regression revealed that low CET within 3 months (p = 0.005, p = 0.002) and high variability (p < 0.001, p < 0.001) were associated with BCs before and after IPTW. Appropriate CET and low variability were associated with better overall survival (p = 0.009 and 0.029). Subgroup analysis indicated that long cold ischemia time (CIT), high bilirubin and low CET had a higher relative risk and raised the incidence of BCs. CONCLUSIONS: Adequate CET and low variability of tacrolimus ameliorated nonearly BCs incidence and improved survival.

Elevated preoperative CA125 levels predicts poor prognosis of hilar cholangiocarcinoma receiving radical surgery.

BACKGROUND: Preoperative serum carbohydrate antigen 125 (CA125) is used to judge the diagnosis and prognosis of various tumors. However, the relationship between preoperative serum CA125 and prognosis of hilar cholangiocarcinoma (HCCA) has not been proven. This study aims to evaluate preoperative serum CA125 in predicting the prognosis of HCCA after resection. METHODS: A total of 233 patients after radical resection of HCCA were included. The associations between the levels of preoperative serum CA125 and the clinicopathological characteristics of patients were analyzed. Survival curves were calculated using the Kaplan-Meier method. Univariate and multivariate Cox regression models were used to identify independent risk factors associated with recurrence-free survival (RFS) and overall survival (OS). RESULTS: Among 233 patients, 198 (84.97%) with normal CA125 levels (≤35 U/mL) had better OS and RFS than 35 (15.02%) patients with higher CA125 levels (>35 U/mL). Preoperative serum CA125 was significantly correlated with tumor size, Bismuth-Corlette classification, microvascular invasion and carcinoembryonic antigen (CEA) (p < 0.001, p = 0.040, p = 0.019 and p = 0.042, respectively). The results of multivariable Cox regression showed that preoperative serum CA125 >35 U/mL (p = 0.002, HR = 1.910 for OS; p = 0.006, HR = 1.755 for RFS), tumor classification (p < 0.001, HR = 2.110 for OS; p = 0.006, HR = 1.730 for RFS), lymph node metastasis (p < 0.001, HR = 1.795 for OS; p < 0.001, HR = 1.842 for RFS) and major vascular invasion (p = 0.002, HR = 1.639 for OS; p = 0.005, HR = 1.547 for RFS) were independent risk factors for both OS and RFS. CONCLUSIONS: Preoperative serum CA125 is a good tumor marker for predicting prognosis after radical surgery for HCCA.

Low preoperative prealbumin predicts the prevalence of complications following liver transplantation.

BACKGROUND: As a nutritional index, preoperative serum prealbumin highly correlates with surgical complications. However, the correlation between preoperative prealbumin and postoperative complications remains unclear in liver transplantation (LT). METHODS: A total of 191 patients who underwent LT between 2015 and 2019 were included in the retrospective analysis. According to a cut-off value calculated from a receiver operating characteristic (ROC) curve, the patients were divided into normal and low preoperative prealbumin groups. Univariable and multivariable logistic regression analyses were used to identify independent risk factors for postoperative complications. In addition, patients were divided into subgroups by Model for End-stage Liver Disease (MELD) score, and the association between preoperative prealbumin and postoperative complications was also assessed in each group. RESULTS: A total of 111 (58.1%) patients were included in the low prealbumin group based on a cut-off value of 120 mg/L. The area under the ROC curve (AUC) was 0.754 (95% confidence interval [CI] 0.678-0.832). Low prealbumin (95% CI 1.51-12.8, P = 0.007) was identified as a predictor for postoperative complications based on multivariable regression. In the low and normal prealbumin groups, the prevalence rates of postoperative complications were 27.5% and 8.0% (P = 0.003) in the MELD score ≤ 15 subgroup and 53.3% and 20.0% (P = 0.197) in the MELD score > 15 subgroup, respectively. CONCLUSIONS: Preoperative prealbumin was associated with postoperative complications in LT, and preoperative nutritional support benefitted postoperative recovery, especially for patients with low MELD scores.