BACKGROUND & AIMS:Endothelial cell (EC) damage is an initiating event in acute cellular rejection after liver transplantation (LT). However, the origin and characteristics of post-transplant neonatal ECs remain controversial. We aimed to uncover the mechanisms underlying EC-T cell interactions after transplantation and to develop an EC-targeted strategy to alleviate transplant rejection. METHODS:Leveraging single-cell RNA sequencing from 13 human and 4 murine liver allografts, we mapped the functional atlas of ECs. Allogeneic orthotopic LT in CAG;R26-tdTomato and Cd34-CreERT2;R26-tdTomato mice confirmed the cellular origin of ECs. We used CellChat, multiplex immunohistochemistry, and in vitro co-culture models to investigate the mechanism of EC-T cell interactions. Using a platelet-based bio-delivery system, we achieved targeted delivery of a CXCL12 monoclonal antibody (αCXCL12). RESULTS:ECs in transplanted livers exhibited a dual origin, being derived from both donor and recipient cells. Recipient-derived ECs were characterized by high CD34 expression, high stemness, and pro-inflammatory characteristics. Using genetic lineage-tracing mice combined with an orthotopic LT model, we found that recipient CD34+ cell-derived ECs peaked at 2 weeks post-LT and declined by 4 weeks, consistent with the temporal pattern of rejection. We further identified that CD34+ ECs recruit and potentiate Th1 and cytotoxic CD8+ T cells via the CXCL12-CXCR4 axis and co-stimulatory molecules. In turn, cytotoxic CD8+ T cells induced pyroptosis of CD34+ cell-derived ECs through the Caspase1-GSDMD pathway. Platelets loaded with αCXCL12 specifically targeted ECs in the transplanted liver, reducing T-cell infiltration and mitigating rejection. CONCLUSIONS:We identified a population of recipient-derived CD34+ ECs that exacerbates acute rejection by activating T cells through the CXCL12-CXCR4 axis. We further developed a platelet-based delivery strategy that precisely targets EC-derived CXCL12 and effectively prevents acute cellular rejection. IMPACT AND IMPLICATIONS:We integrated single-cell transcriptomic data from human and murine liver allografts to delineate the dual cellular origins and functional atlas of endothelial cells. Using lineage-tracing mice in an allogeneic orthotopic liver transplantation model, we tracked the fate of CD34+ cells and demonstrated the contribution of recipient-derived CD34-lineage endothelial cells to liver allograft angiogenesis. These CD34-lineage endothelial cells recruited T cells through the CXCL12-CXCR4 axis and activated them via co-stimulatory molecules. Furthermore, a platelet-based biological delivery strategy targeting CXCL12 in CD34-lineage endothelial cells alleviated T cell-mediated rejection. This study provides an endothelial cell-centered perspective and proposes a potential novel immunosuppressive strategy for liver transplantation.

To evaluate the association between coronary computed tomography angiography (CCTA)-based parameters and major adverse cardiovascular events (MACEs) in liver transplantation (LT) recipients and assess the incremental prognostic value of CCTA over the cardiovascular risk in orthotopic liver transplantation (CAR-OLT) score. A dual-center 395 LT recipients were enrolled. The endpoints were 1-year MACE and MACE after LT. The CAR-OLT score was calculated. An imaging model for predicting 1-year MACE after LT was constructed based on the independent CCTA-based predictors. A combined model was established by integrating the independent imaging predictors with the CAR-OLT score. Coronary artery disease-reporting and data system (CAD-RADS) score (odds ratio [OR], 3.15; P = .020) and CT-derived translesional fractional flow reserve gradient across the lesion with the highest-grade stenosis (ΔFFRCT) (OR 2.23, P = .001) were identified as the independent imaging predictors for 1-year MACE after LT. The combined model outperformed the CAR-OLT score with a higher area under the curve value for predicting 1-year MACE after LT (0.793 vs 0.668, P = .044) and a higher C-index for predicting MACE after LT (0.766 vs 0.659, P < .001). CAD-RADS score and ΔFFRCT can predict MACE after LT and provide incremental value to the CAR-OLT score.

Background:Pyroptosis, a type of programmed cell death, exerts direct influence on inflammatory processes and immune response. A previous study suggests that miltirone exhibits notable anti-tumor activities and has been shown to induce tumor cell pyroptosis. Nevertheless, the therapeutic value of miltirone in kidney renal clear cell carcinoma (KIRC) remains underexplored. Methods and results:Using TCGA pan-cancer data, we uncovered widely expressed pyroptosis-related genes (NLRP3 and AIM2). Mechanistically, the genomic amplification alteration and high CNV percentages in pan-cancer induced an abnormal expression. StromalScore analysis suggested that NLRP3 and AIM2 were activated by the tumor immune microenvironment in KIRC. Enrichment analysis indicated that NLRP3 and AIM2 regulated the inflammatory response and were related to immune infiltration in KIRC. Furthermore, Kaplan-Meier curve and ROC analysis indicated that a high expression of AIM2 was associated with a worse prognosis of KIRC patients. MTT assays and flow cytometry revealed that miltirone treatment induced KIRC cell pyroptosis and inhibited cell proliferation, with changes in the expression level of NLPR3, AIM2, caspase-3, and GSDMD. The enhancement of cell pyroptosis and the release of IL-1β and IL-18 cytokines were reversed by pretreatment with the pyroptosis inhibitor VX-765. Conclusions:Our study revealed the prognostic value of NLRP3 and AIM2 in KIRC. Miltirone treatment inhibited KIRC cell proliferation and enhanced cell pyroptosis via the NLRP3/AIM2/GSDMD axis. This study provides a novel molecular mechanism and potential therapeutic targets in KIRC progression.

Background and Aims:Liver transplant rejection significantly affects patient prognosis. Myeloid-derived suppressor cells (MDSCs), known for their potent immunoregulatory functions, represent a promising target for managing liver transplant rejection. This study aimed to systematically characterize the diversity of MDSC subsets and their context-dependent functions, particularly within the context of transplant tolerance. Methods:We analyzed clinical and murine liver transplants using single-cell RNA sequencing, bulk RNA sequencing, flow cytometry, multiplex immunohistochemistry, and co-culture assays to phenotype MDSC subsets. Results:Single-cell RNA sequencing analysis of human and murine samples revealed MDSC involvement in transplant rejection. In mice, MDSC scores followed a normal distribution during the first week post-transplant and correlated with clinical flow cytometry data at one month. A distinct LDLR+ monocytic MDSC (M-MDSC) subset was identified and confirmed through spatial mapping by multiplex immunohistochemistry. Flow cytometry demonstrated dynamic changes in LDLR+ M-MDSCs across tissues (liver, spleen, peripheral blood, bone marrow, and lymph nodes), with a peak during acute rejection. Co-culture experiments showed that LDLR-/- M-MDSCs exhibited reduced Arg-1/iNOS expression and an impaired capacity to induce inhibitory receptors (TIGIT, PD1, CTLA-4) or suppress effector molecules (GZMB, IFN-γ, IL-2) in CD8+ T cells. Conclusions:These findings highlight the critical role of MDSCs in liver transplant rejection. LDLR+ M-MDSCs exhibited enhanced immunosuppressive properties, underscoring their potential clinical relevance in mitigating rejection and promoting immune tolerance.

Ischemia-reperfusion injury (IRI) and subsequent rejection remain the paramount pathological barriers to long-term graft survival following liver transplantation. Traditionally viewed as mere ‘first responders’ in the acute inflammation of IRI, neutrophils are now recognized, based on recent advances, as pivotal regulators that bridge innate and adaptive immunity throughout the entire post-transplant course. This review aims to systematically delineate the dual pathological mechanisms of neutrophils in both IRI and rejection post-LT. During the initial phase of IRI, we focus on the robust activation of neutrophils, driven by damage-associated molecular patterns (DAMPs), with a particular emphasis on the formation of neutrophil extracellular traps (NETs). NETs act not only as key effectors causing sinusoidal microcirculatory dysfunction and direct hepatocellular injury, but their released histones and proteases also serve as potent danger signals, amplifying the local inflammatory cascade. The central thesis of this review is that the inflammatory microenvironment, orchestrated by neutrophils during IRI, provides the essential immunological substrate for subsequent rejection. We delve into the mechanisms by which neutrophils bridge to adaptive immunity: NETs serve as a scaffold for autoantigens, activating B cells and promoting the production of donor-specific antibodies (DSA), thereby driving antibody-mediated rejection (AMR). Concurrently, chemokines released by neutrophils efficiently recruit effector T cells and, through interactions with antigen-presenting cells, exacerbate cell-mediated rejection (CMR). Finally, we prospect future therapeutic directions, emphasizing that targeting common pathways within this ‘injury-immunity’ axis—such as inhibiting DAMP release, blocking NET formation, or employing pro-resolving mediators to actively terminate inflammation—represents a pivotal strategy to break the vicious cycle of IRI and rejection and achieve long-term immune tolerance.

In experimental liver transplantation, the rat model is the gold standard for investigating transplant immunology and metabolic processes; however, reconstructing the exceedingly fine hepatic artery (~0.5 mm) presents a formidable technical challenge. To circumvent this, the simplified non-arterialized rat liver transplantation (NArLT) model is widely utilized. Unfortunately, severe biliary complications-such as bile leakage and ischemic cholangitis-arising from arterial deprivation frequently restrict the long-term survival of recipients. This obstacle significantly limits research on key topics, including long-term host-graft immunocompatibility and chronic rejection. Herein, we present an optimized protocol for the NArLT model that incorporates critical technical refinements to successfully overcome these ischemic biliary injuries. Key improvements include a significantly shortened anhepatic phase, a "no-touch" biliary dissection technique, thorough biliary tract flushing, and an optimized internal biliary stenting method. After implementing this improved procedure, the recipient survival rate exceeded 94% during the 100-day observation period. Ultimately, this optimized protocol provides a highly reproducible and robust platform to investigate the mechanisms underlying long-term transplant tolerance, thereby supporting the development of novel therapeutic strategies in transplantation medicine.

Abstract The liver immune microenvironment is a complex system regulated by the interaction between circulating immune cells and resident immune cell populations. In recent years, liver resident immune cells (LRICs) have received increasing attention as an important cell population for regulating liver pathology. These types of non‐circulating liver cells have unique adaptability, not only meeting the metabolic needs of the liver but also maintaining its immune homeostasis. The advancement of high‐throughput technology has enabled in‐depth research on the unique origin, developmental pathways, and functional plasticity of LRICs. LRICs can initiate rapid, strong, and long‐lasting tissue‐specific immune responses to effectively curb disease progression. However, these powerful abilities may translate into pathogenic factors in specific situations: triggering tissue damage in the autoimmune environment and mediating graft rejection after liver transplantation. This article systematically reviews the current understanding of these key resident immune cell populations, details their multidimensional and often paradoxical mechanisms of action in a variety of major liver pathologies, and discusses the prospects of emerging therapeutic strategies for these key cell players.

BACKGROUND:The aim of this study was to evaluate the efficacy of nonbiological artificial liver (NBAL) in the treatment of acute liver failure (ALF) and to screen prognostic predictors. METHODS:This study was a single-center retrospective observational study that included 186 ALF patients treated with NBAL (plasma exchange alone, DPMAS alone, or combination therapy). Laboratory parameters (TBil, INR, Cr, etc.) before and after 24 hours of treatment and 28-day and 90-day survival data were collected. Prognostic features were screened by XGBoost and Random Forest, independent risk factors were analyzed by Cox regression, and column-line plots were constructed. RESULTS:The 90-day poor prognosis group (mortality/liver transplantation) presented a significant high-risk phenotype as evidenced by a higher MELD score (34.46 vs. 29.84, p < 0.001), greater severity of hepatic encephalopathy (64.6% vs. 38.8% share of grades III - IV, p < 0.001), and concomitant overall deterioration in the indicators of hepatic and renal impairment (TBil, INR, and Cr) (all p < 0.001). The machine learning model further validated the predictive value of the dynamic metrics, with TBil% on day 1 of treatment with a decision-tree significance of 26.3%, significantly outperforming traditional baseline metrics (e.g., MELD score and TBil). Risk stratification based on median TBil% (14.26%) showed a 28-day all-cause mortality rate of 46.24% (vs. 10.75% in the low-risk group, p < 0.001) in the high-risk group and a 90-day survival of only 36.6% (vs. 75.3% in the low-risk group, p < 0.0001). Each 1% decrease in 24-hour TBil% increased the risk of mortality by 7% (HR = 0.93, p < 0.001), while baseline MELD score (HR = 1.07, p < 0.001) and 24-hour INR (HR = 1.70, p < 0.001) were independent risk factors. CONCLUSIONS:Early TBil clearance in ALF treated with NBAL is a strong predictor of 90-day survival, and baseline MELD score and post-treatment INR are also independent risk factors.

Liver cancer remains one of the leading causes of cancer-related death worldwide, and its immunologically "cold" tumor microenvironment continues to undermine the efficacy of immunotherapy. Among the many stroma-derived factors, C-X-C motif chemokine ligand 12 (CXCL12) is regarded as a central regulator of immune exclusion, mediating limited effector T cell infiltration and promoting tumor progression through C-X-C chemokine receptor type (CXCR) 4 and CXCR7. This review summarizes the latest understanding of the CXCL12-CXCR4/CXCR7 axis in liver cancer, with particular emphasis on the new perspective that cancer-associated fibroblast (CAF) heterogeneity shapes distinct CXCL12 niches, and that CXCL12 constructs a spatial barrier at the tumor margin to reinforce immune privilege. We further evaluate therapeutic strategies targeting this axis, including antagonists, neutralizing antibodies, and novel delivery systems, and explore their combination with immune checkpoint inhibitors (ICIs), emerging immunotherapies, and anti-angiogenic treatments. In addition, we propose the clinical potential of CXCL12-CXCR4/CXCR7 axis-related molecules as predictive biomarkers, highlighting the translational value of resistance mechanisms and immune re-sensitization. Through these new perspectives, this review provides an innovative summary and future research directions for understanding the key role of CXCL12 in the liver cancer immune microenvironment and for developing targeted combination immunotherapy strategies.

Split liver transplantation addresses organ shortage; however, the outcomes of and risk factors for full-right/full-left split liver transplantation (FR/FLSLT) require validation using multicenter data. This retrospective multicenter study included 132 FR/FLSLT recipients from 5 Chinese centers (May 2016 to November 2024). Risk factors affecting survival were analyzed, stratified by graft-to-recipient weight ratio (GRWR) and risk factors. The overall 3-year recipient and graft survival rates were 84.1% and 81.8%, respectively. Recipients with a GRWR ≤1.15 exhibited significantly lower 3-year survival vs GRWR >1.15 (58.1% vs 91.7% recipient survival; 55.3% vs 89.8% graft survival; P < .001). Multivariate analysis identified recipient age >52 years and model for end-stage liver disease score >15 as independent mortality risk factors. In patients without risk factors, no mortality or graft-loss events were observed in the GRWR ≤1.15 group, but the small sample size (n = 3) limits the interpretation. However, with ≥1 risk factor, a GRWR ≤1.15 significantly increased mortality (hazard ratio 8.81, P < .001) and graft loss (hazard ratio 7.50, P < .001). FR/FLSLT with GRWR >1.15 demonstrated favorable outcomes. GRWR ≤1.15 grafts may be considered for recipients without identified risk factors (age ≤52 years, model for end-stage liver disease score ≤15), and this requires further multicenter validation.

Tissue-resident memory T cells (TRMs) are a non-circulating subset of memory T cells that reside long-term in peripheral tissues. Once considered passive sentinels, TRMs are now recognized as active regulators of transplant immunity. This review summarizes their phenotypic and functional characteristics across key transplanted organs, including kidney, liver, lung, intestine, skin, and heart. Depending on their activation state and microenvironment, TRMs can promote rejection and modulate local immune balance. Advances in single-cell and spatial profiling have revealed TRM heterogeneity, donor–recipient dynamics, and distinct transcriptional programs. We also highlight therapeutic targets such as NKG2D, IL-15, RORγt, and PD-1, and discuss their potential as biomarkers and immunomodulatory tools. Understanding TRMs as both drivers and regulators of alloimmunity offers new strategies for improving transplant outcomes.