Thrombin and factor Xa link the coagulation system with Liver fibrosis

Background: Thrombin activates hepatic stellate cells via protease-activated receptor-1. The role of Factor Xa (FXa) in hepatic fibrosis has not been elucidated. We aimed to evaluate the impact of FXa and thrombin in vitro on stellate cells and their respective inhibition in vivo using a rodent model of hepatic fibrosis. Methods: HSC-LX2 cells were incubated with FXa and/or thrombin in cell culture, stained for αSMA and relative gene expression and gel contraction calculated. C57BL/6 J mice were administered thioacetamide (TAA) for 8 weeks with Rivaroxaban (n = 15) or Dabigatran (n = 15). Control animals received TAA alone (n = 15). Fibrosis was scored and quantified using digital image analysis and hepatic tissue hydroxyproline estimated. Results Stellate cells treated with FXa and thrombin demonstrated upregulation of procollagen, TGF-beta, αSMA and significant cell contraction (43.48%+/− 4.12) compared to culturing with FXa or thrombin alone (26.90%+/− 8.90, p = 0.02; 13.1%+/− 9.84, p < 0.001). Mean fibrosis score, percentage area of fibrosis and hepatic hydroxyproline content (2.46 vs 4.08, p = 0.008; 2.02% vs 3.76%, p = 0.012; 276.0 vs 651.3, p = 0.0001) were significantly reduced in mice treated with the FXa inhibitor compared to control mice. FXa inhibition was significantly more effective than thrombin inhibition in reducing percentage area of fibrosis and hepatic hydroxyproline content (2.02% vs 3.70%,p = 0.031; 276.0 vs 413.1,p = 0.001). Conclusions: FXa promotes stellate cell contractility and activation. Early inhibition of coagulation using a FXa inhibitor significantly reduces TAA induced murine liver fibrosis and may be a viable treatment for liver fibrosis in patients

The PDGFRα-laminin B1-keratin 19 cascade drives tumor progression at the invasive front of human hepatocellular carcinoma

Human hepatocellular carcinomas (HCCs) expressing the biliary/hepatic progenitor cell marker keratin 19 (K19) have been linked with a poor prognosis and exhibit an increase in platelet-derived growth factor receptor a (PDGFR alpha) and laminin beta 1 (LAMB1) expression. PDGFR alpha has been reported to induce de novo synthesis of LAMB1 protein in a Sjogren syndrome antigen B (La/SSB)-dependent manner in a murine metastasis model. However, the role of this cascade in human HCC remains unclear. This study focused on the functional role of the PDGFR alpha-La/SSB-LAMB1 pathway and its molecular link to K19 expression in human HCC. In surgical HCC specimens from a cohort of 136 patients, PDGFR alpha expression correlated with K19 expression, microvascular invasion and metastatic spread. In addition, PDGFR alpha expression in pre-operative needle biopsy specimens predicted poor overall survival during a 5-year follow-up period. Consecutive histological staining demonstrated that the signaling components of the PDGFR alpha-La/SSB-LAMB1 pathway were strongly expressed at the invasive front. K19-positive HCC cells displayed high levels of alpha 2 beta 1 integrin (ITG) receptor, both in vitro and in vivo. In vitro activation of PDGFR alpha signaling triggered the translocation of nuclear La/SSB into the cytoplasm, enhanced the protein synthesis of LAMB1 by activating its internal ribosome entry site, which in turn led to increased secretion of laminin-111. This effect was abrogated by the PDGFR alpha-specific inhibitor crenolanib. Importantly LAMB1 stimulated ITG-dependent focal adhesion kinase/Src proto-oncogene non-receptor tyrosine kinase signaling. It also promoted the ITG-specific downstream target Rho-associated coiled-coil containing protein kinase 2, induced K19 expression in an autocrine manner, invadopodia formation and cell invasion. Finally, we showed that the knockdown of LAMB1 or K19 in subcutaneous xenograft mouse models resulted in significant loss of cells invading the surrounding stromal tissue and reduced HepG2 colonization into lung and liver after tail vein injection. The PDGFR alpha-LAMB1 pathway supports tumor progression at the invasive front of human HCC through K19 expression

Handling Overlapping Asymmetric Data Sets—A Twice Penalized P-Spline Approach

\ua9 2024 by the authors.Aims: Overlapping asymmetric data sets are where a large cohort of observations have a small amount of information recorded, and within this group there exists a smaller cohort which have extensive further information available. Missing imputation is unwise if cohort size differs substantially; therefore, we aim to develop a way of modelling the smaller cohort whilst considering the larger. Methods: Through considering traditionally once penalized P-Spline approximations, we create a second penalty term through observing discrepancies in the marginal value of covariates that exist in both cohorts. Our now twice penalized P-Spline is designed to firstly prevent over/under-fitting of the smaller cohort and secondly to consider the larger cohort. Results: Through a series of data simulations, penalty parameter tunings, and model adaptations, our twice penalized model offers up to a 58% and 46% improvement in model fit upon a continuous and binary response, respectively, against existing B-Spline and once penalized P-Spline methods. Applying our model to an individual’s risk of developing steatohepatitis, we report an over 65% improvement over existing methods. Conclusions: We propose a twice penalized P-Spline method which can vastly improve the model fit of overlapping asymmetric data sets upon a common predictive endpoint, without the need for missing data imputation

How effective are experienced hepatologists at staging fibrosis using non-invasive fibrosis tests in patients with metabolic dysfunction-associated steatotic liver disease?

\ua9 2024 The Author(s). Alimentary Pharmacology &amp; Therapeutics published by John Wiley &amp; Sons Ltd. Background: Sequential use of non-invasive fibrosis tests (NITs) to identify patients with advanced hepatic fibrosis is recommended. However, it remains unclear how reliable clinicians are staging liver fibrosis using combinations of NITs. Aim: Our aim was to assess concordance between NIT-based ‘clinician fibrosis assessment (CFA)’ and histology in patients with metabolic dysfunction-associated steatotic liver disease (MASLD) and compare this with established algorithmic approaches. Methods: Six experienced hepatologists independently staged 230 MASLD patients for advanced fibrosis (F0-2 vs F3-4) using FIB-4, FIB-4+ELF, FIB-4+ vibration controlled transient elastography (VCTE; Fibroscan™) and FIB-4+ELF+VTCE. Concordance between histology and CFA or algorithmic approaches were assessed. Results: A total of 230 patients were included (median age 54 [22–78] years; 55% female; median FIB-4 1.21 [IQR: 0.78–1.91]; ELF 9.3 [IQR: 8.6–10.2]; VCTE 9.4 [IQR: 6.3–14.3]; 41% F0-1, 22% F2, 21% F3 and 16% F4). Overall, area under the receiver operator curves for histologic F3-4 for the raw tests were 0.84 for FIB-4, 0.86 for ELF and 0.86 for VCTE. Concordance between the hepatologists was good (FIB4, κ = 0.64; FIB-4+ELF, κ = 0.70; FIB-4+VCTE, κ = 0.69; FIB-4+ELF+VCTE, κ = 0.70). Concordance between individual CFA and histology was variable, which was reflected in variability in sensitivity (44%–84%) and specificity (76%–94%). Concordance with histology was better when clinicians used NIT combinations. Purely algorithmic approaches, particularly sequential use of FIB-4 then VCTE, tended to perform better than the CFA. Conclusions: Adhering to the recommended algorithmic approaches using NITs to stage fibrosis tended to perform more accurately than less-structured clinician NIT-based assessments conducted by experienced hepatologists

Hot and cold fibrosis: The role of serum biomarkers to assess immune mechanisms and ECM-cell interactions in human fibrosis

\ua9 2025 The Author(s)Fibrosis is a pathological condition characterised by excessive accumulation of extracellular matrix (ECM) components, particularly collagens, leading to tissue scarring and organ dysfunction. In fibrosis, an imbalance between collagen synthesis (fibrogenesis) and degradation (fibrolysis) results in the deposition of fibrillar collagens disrupting the structural integrity of the ECM and, consequently, tissue architecture. Fibrosis is associated with a wide range of chronic diseases, including cirrhosis, kidney fibrosis, pulmonary fibrosis, and autoimmune diseases. Recently, the concept of “hot” and “cold” fibrosis has emerged, referring to the immune status within fibrotic tissues and the nature of fibrogenic signalling. Hot fibrosis is characterised by active immune cell infiltration and inflammation, while cold fibrosis is associated with auto- and paracrine myofibroblast activation, immune cell exclusion and quiescence. In this article, we explore the relationship between hot and cold fibrosis, the role of various types of collagens and their biologically active fragments in modulating the immune system, and how serological ECM biomarkers can help improve our understanding of the disease-relevant interactions between immune and mesenchymal cells in fibrotic tissues. Additionally, we draw lessons from immuno-oncology research in solid tumours to shed light on potential strategies for fibrosis treatment and highlight the advantage of having a “hot fibrotic environment” to treat fibrosis by enhancing collagen degradation through modulation of the immune system