Hepatology Communications最新文献

Background: The liver plays a critical role in metabolism and immune function, yet the contributions of its heterogeneous cell types to these processes remain unclear. While most liver studies focus on adults, pediatric liver diseases often present differently, underscoring the need for age-specific research.

Methods: To better understand cellular drivers of childhood liver diseases, we generated single-cell RNA-sequencing maps of the normal pediatric liver and used this map to examine disease-related populations in biopsies from pediatric patients with intestinal failure-associated liver disease (IFALD).

Results: The normal pediatric liver map consists of 42,660 cells from 9 donors under 17 years of age. Compared with normal adult liver (26,372 cells; 7 donors, age 26-69), pediatric livers exhibited differences in myeloid populations. Specifically, pediatric Kupffer-like cells (MARCO+C1QA+VSIG4+) exhibited higher expression of immune activation genes, including CCL4, CCL3, and IL1B. In vitro stimulation confirmed more IL-1β-secreting myeloid cells in pediatric versus adult livers, supporting these findings. Using the pediatric atlas as a reference, we analyzed 3 IFALD biopsies (11,969 cells; 3 donors, under 9 y of age) and identified increased expression of fibrosis-associated genes (eg, LY96) in Kupffer-like cells. In addition, mesenchymal cells in IFALD showed fibrotic gene modules resembling adult liver cells more than healthy pediatric cells. These signatures, undetectable when comparing IFALD to adult liver alone, highlight the value of a pediatric map.

Conclusion: Taken together, our healthy pediatric liver atlas reveals distinct age-related signatures and provides a background against which to interpret pediatric liver disease data.

Background: Primary hepatocytes are commonly used in vitro to model liver metabolism, but prolonged culturing results in dedifferentiation and potentially limits the applicability of this model.

Methods: We characterized the transcriptome and proteome of full liver and primary hepatocytes as either freshly isolated cells or after 24 hours of 2D-culturing.

Results: We found that 2D-culturing for 24 hours changes more than 10,000 genes and 3000 proteins compared with freshly isolated cells, accompanied by a decrease in transcriptional heterogeneity and a loss of zonal markers. Moreover, there were changes in proteins associated with the extracellular matrix, in mitochondrial and ribosomal protein abundances, as well as an increase in the abundance of acute-phase response proteins.

Conclusion: Collectively, primary mouse hepatocytes in culture rewire the transcriptome and proteome, which may affect the utility of this model to study physiological and molecular mechanisms related to the liver. We developed the Shiny app "Hepamorphosis" (https://cbmr.ku.dk/research/resources/shiny-apps/), which allows users to explore RNA/protein correlations, zonation profiles, and cell-type-specific transcription in full liver and cultured hepatocytes.

Background: Primary sclerosing cholangitis (PSC) is a cholestatic liver disease that can cause uneven fibrosis throughout the liver. Spatial heterogeneity in liver stiffness (LS) by magnetic resonance elastography (MRE) was compared in patients with PSC and metabolic dysfunction-associated steatotic liver disease (MASLD).

Methods: Variability of LS was defined as the difference between the maximum and minimum LS divided by the maximum LS. The coefficient of variation (CoV) was calculated as the SD of LS divided by the mean of LS. MREs were classified as homogenous or heterogenous if the variability of LS was less than or greater than the mean variability, respectively.

Results: A total of 105 patients (PSC: n=66, MASLD: n=39) were included. In both PSC and MASLD, the variability of LS increased with increasing mean LS (r=0.31, p=0.01 and r=0.57, p=0.0002, respectively). CoV correlated with mean LS in patients with MASLD (r=0.34, p=0.03), but not PSC (r=0.19, p=0.12). Among patients with PSC, neither variability nor CoV of LS were predictors of transplant-free survival (TFS) or hepatic decompensation (HD). Mean LS was a significant predictor of TFS (HR 1.52, p=0.004) and HD (HR 1.94, p<0.0001), independent of LS variability or CoV.

Conclusions: Spatial heterogeneity of LS increases with progressive disease but is not associated with clinical outcomes in PSC. Mean LS predicts clinical outcomes in patients with PSC independent of LS spatial heterogeneity.

Background: Cirrhosis and cirrhosis-related deaths have risen in the United States in recent years. Ascites is a common complication, often requiring large-volume paracentesis (LVP). The American Association for the Study of Liver Diseases (AASLD) recommends the administration of albumin in conjunction with LVP to prevent further complications of cirrhosis. Emerging research in cirrhosis care reveals significant variations in outcomes among different demographics. Therefore, we assessed the use of guideline-adherent albumin and outcomes in U.S. patients undergoing LVPs, particularly at the intersection of race, ethnicity, socioeconomic disparities, and cirrhosis.

Methods: This retrospective study utilized Cerner Real World Data to identify adults with cirrhosis and ascites undergoing LVP between January 2016 and June 2022. We assessed albumin utilization patterns across racial and ethnic groups and payor types, and their overall impact on acute kidney injury (AKI)-related hospitalization using an adjusted generalized linear model (aGLM).

Results: We identified 736 patients: 301 in the LVP + albumin group and 435 in the LVP-only group. Despite clinical recommendations, only 41% undergoing LVPs received albumin. White patients and commercially insured patients received albumin at higher rates (p=0.042 and p=0.009, respectively). The overall rate of AKI-related admissions within the 30-day post-procedure period was 26%. However, patients who received albumin during LVP had a 36% lower risk of short-term AKI-related hospitalization (OR: 0.64; p=0.03).

Conclusions: These findings indicate a potential for broader albumin utilization in U.S. patients with refractory ascites undergoing repeated LVPs to reduce AKI-related admissions.

Background: Pediatric cholestatic liver diseases can be characterized by rapidly progressive fibrosis. A multicenter cross-sectional analysis of vibration-controlled elastography in biliary atresia (BA), alpha-1 antitrypsin deficiency (A1AT), and Alagille syndrome (ALGS) was leveraged to interrogate the plasma proteome relative to liver stiffness measurements (LSM).

Methods: Slow off-rate modified aptamer scanning profiling of >7000 proteins in plasma from 187 children with BA (n=93), A1AT (n=31), ALGS (n=46), and healthy pediatric controls (n=17) was performed, and correlations with LSM were undertaken.

Results: There was an abundance of LSM correlated proteins (BA n=2720, A1AT n=694, ALGS n=5968). Interestingly, a distinct plasma proteome was found in ALGS relative to BA and A1AT. Weighted Correlation Network Analysis identified groups of proteins with strong LSM correlation (eg, in a BA module of interest, Pearson correlation coefficient 0.79, p=5´0-21). Machine learning developed models predicting LSM as a continuous variable (median R2=0.62 for BA). For BA, time to transplant could be predicted equally well by the proteome or clinical parameters (elastic net models achieved a C-index using proteome 0.91, clinical parameters 0.91, proteome and clinical parameters 0.90). Single-cell transcriptomics predicted the potential hepatic cell of origin for the most informative proteins, which included macrophage, mesenchymal, mesothelial, and endothelial cells. The epithelial-to-mesenchymal transition pathway was enriched in LSM correlated proteins in all 3 diseases.

Conclusions: The plasma proteome is highly correlated in a disease-specific fashion with LSM in BA, A1AT, and ALGS. These correlations provide unique opportunities to identify biomarkers and focus attention on epithelial-to-mesenchymal transition in pediatric cholestasis.

Background: Treatment goals in primary biliary cholangitis (PBC) are increasingly aspirational, aiming for normal serum liver tests. One of the add-on therapies to ursodeoxycholic acid (UDCA) is with the approved farnesoid X receptor (FXR) agonist obeticholic acid (OCA), alongside off-label use of fibrates (peroxisome proliferator-activated receptor [PPARs]). We report our experience of synergistic FXR-PPAR-UDCA combination therapy in PBC.

Methods: A review of patients with PBC seen between July 2022 and July 2023 was performed across the autoimmune liver disease programme at the Toronto Centre for Liver Disease. Univariate and multivariate analyses were performed.

Results: Four hundred seventy patients with PBC were seen, of which 71% were treated with UDCA only, 7% UDCA-OCA, 11.3% UDCA-fibrates, and 10.6% UDCA-OCA-fibrates. Among 50 patients on triple therapy, 82% had OCA as the first add-on therapy. Most patients (92%) received bezafibrate, while 8% had fenofibrate. Forty-eight patients were included in the final analysis. The mean follow-up time after triple therapy was 17.4 months. Triple therapy demonstrated median ALP reductions after 6 months of 33.3% (95% CI: 27.9%-37.6%) and 39.1% (95% CI: 30.7%-46.2%) at the last follow up; 30.2% of the patients had a normal serum ALP at 6 months, while 11.9% had normal ALP, AST, ALT, and bilirubin. Subgroup analysis of 28 patients followed for at least 12 months showed a 44.7% (95% CI: 33.3%-50.9%) median reduction in ALP. Liver stiffness remained relatively stable throughout the follow-up. Out of 34 patients with self-reported pruritus before triple therapy, 64.7% reported improvement, 11.8% worsened, and 23.5% had no change in itching intensity. On multivariable analysis, only older age at diagnosis (OR=1.12; 95% CI: 1.02-1.22) positively impacted ALP normalization.

Conclusions: Our data confirm that FXR-PPAR-UDCA triple therapy significantly improves ALP with normalization for 30% of patients with PBC at 6 months.

Background: Hereditary intrahepatic cholestasis is caused by variants of various genes involved in enterohepatic bile circulation, metabolization, and conjugation. Originally classified into 3 groups, the number of contributing genes is still increasing, underlining the need for a deeper understanding of the molecular interaction during intrahepatic cholestasis.

Methods: In the present study, we investigate the interplay of heterozygous variants in 3 cholestasis-associated genes (ABCB11, ABCB4, and MYO5B) by exploiting iPSC-based hepatic organoids from a patient suffering from recurrent intrahepatic cholestasis.

Results: Functional characterization of MRP2-mediated cholyl-lysyl-fluorescein (CLF) and BSEP-mediated Tauro-nor-THCA-24-DBD transport demonstrated a marked reduction of transport in MYO5B-deficient organoids, in comparison to unaffected control organoids. Moreover, iPSC-based organoids derived from the patient carrying 3 heterozygous variants in ABCB11, ABCB4, and MYO5B also exhibited absence of BSEP-mediated Tauro-nor-THCA-24-DBD transport, but functional MRP2-mediated CLF-transport. Interestingly, CRISPR/Cas9-mediated correction of the mutated ABCB11 allele could not restore the impaired BSEP function, suggesting the heterozygous MYO5B variant as the main driver of the transport deficiency. In fact, CRISPR/Cas-mediated correction of the MYO5B variant finally resulted in a restoration of the BSEP-mediated Tauro-nor-THCA-24-DBD transport.

Conclusions: iPSC-based organoids serve as an authentic model for functional assessment of the hepatobiliary transport with fluorescent substrates. This allows the characterization of variants of uncertain significance and other variants in cholestasis-associated genes and revealed that a heterozygous MYO5B variant increases the susceptibility to defective hepatobiliary BSEP-mediated transport.

Background: Tissue-nonspecific alkaline phosphatase (TNAP) expression increases after liver injury, but its role in liver fibrosis remains unclear. This study investigated the effect of TNAP on liver fibrosis and its mechanism in regulating TGF-β1 signaling.

Methods: Human liver samples and a CCl4-induced liver fibrosis mouse model with adv-TNAP and a TNAP inhibitor (tetramisole, Tetra) were used to study the function of TNAP in liver fibrosis. Primary HSCs were used to study the mechanism of TNAP in regulating the TGF-β1 signal.

Results: Elevated TNAP expression was observed in human and murine fibrotic liver tissues, correlating with increased fibrotic markers. In vivo experiments using TNAP overexpression and inhibition in a CCl4-induced liver fibrosis mouse model demonstrated that TNAP exacerbated, while its inhibition alleviated, liver fibrosis. In vitro studies revealed that TNAP regulated TGF-β1 conversion and HSCs activation through the TGF-β1/SMAD pathway. TNAP facilitated TGF-β1 conversion by promoting the interaction between CD47 and thrombospondin-1 (TSP1). Membrane expression of CD47 modulated by TNAP might contribute to the binding effect of CD47 and TSP1.

Conclusions: TNAP plays a critical regulatory role in TGF-β1-mediated liver fibrosis, probably by promoting the binding of CD47/TSP1. Targeting TNAP-mediated pathways may offer new therapeutic strategies for liver fibrosis.