Progressive alcohol-related liver fibrosis is characterised by imbalanced collagen formation and degradation

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

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.

Noninvasive assessment of hepatic decompensation

Noninvasive tests (NITs) are used in all aspects of liver disease management. Their most prominent break-through since the millennium has been in advancing early detection of liver fibrosis, but their use is not limited to this. In contrast to the symptom-driven assessment of decompensation in patients with cirrhosis, NITs provide not only opportunities for earlier diagnoses but also accurate prognostication, targeted treatment decisions, and a means of monitoring disease. NITs can inform disease management and decision-making based on validated cutoffs and standardized interpretations as a valuable supplement to clinical acumen. The Baveno VI and VII consensus meetings resulted in tangible improvements to pathways of care for patients with compensated and decompensated advanced chronic liver disease, including the combination of platelet count and transient elastography to diagnose clinically significant portal hypertension. Furthermore, circulating NITs will play increasingly important roles in assessing the response to interventions against ascites, variceal bleeding, HE, acute kidney injury, and infections. However, due to NITs' wide availability, there is a risk of inaccurate use, leading to a waste of resources and flawed decisions. In this review, we describe the uses and pitfalls of NITs for hepatic decompensation, from risk stratification in primary care to treatment decisions in outpatient clinics, as well as for the in-hospital management of patients with acute-on-chronic liver failure. We summarize which NITs to use when, for what indications, and how to maximize the potential of NITs for improved patient management.

Markers of Collagen Formation and Degradation in Serum and Pancreatic Fluid Collections in Patients With Acute and Chronic Pancreatitis

OBJECTIVES

Current knowledge on the fibro-inflammatory process underlying chronic pancreatitis originates from animal studies or human studies based on circulating biomarkers. To provide new insight into the underlying fibro-inflammatory processes, we simultaneously assessed fibrosis biomarkers in pancreatic fluid collections and the systemic circulation.

MATERIALS AND METHODS

This prospective observational cross-sectional study included patients with acute and chronic pancreatitis undergoing drainage of pancreatic fluid collections, as well as 20 healthy controls (only serum levels). PRO-C3, PRO-C11 and PRO-C19 (markers of collagen formation), and C3M and C4M (markers of collagen degradation) were evaluated for both compartments (serum and fluid collection).

RESULTS

Forty-three patients were included: 26 with walled-off necrosis and 17 with pseudocyst. Serum levels of all 5 fibrosis biomarkers were elevated in patients as compared to controls (all P < 0.001). PRO-C3 levels were significantly higher in pancreatic fluid vs serum (280.6 vs 20.8 ng/mL, P < 0.001). In contrast, levels of C3M (20.5 vs 13.1 ng/mL, P = 0.003), PRO-C19 (64.9 vs 14.3 nM, P < 0.001), and C4M (55.6 vs 20.4 ng/mL, P < 0.001) were significantly higher in serum vs pancreatic fluid.

CONCLUSIONS

The high serum levels in patients suggest increased overall fibrotic activity in pancreatitis patients as compared to healthy controls. PRO-C3 elicited higher levels in the pancreatic fluid, indicating localized fibrotic activity.

Umbilical cord mesenchymal stem cell-derived exosomal Follistatin inhibits fibrosis and promotes muscle regeneration in mice by influencing Smad2 and AKT signaling

BACKGROUND

Promoting muscle regeneration through stem cell therapy has potential risks. We investigated the effect of umbilical cord mesenchymal stem cells (UMSCs) Exosomes (Exo) Follistatin on muscle regeneration.

METHODS

The Exo was derived from UMSCs cells and was utilized to affect the mice muscle injury model and C2C12 cells myotubes atrophy model. The Western blot, qRT-PCR and IF were utilized to determine the effects of Exo on the levels of Follistatin, MyHC, MyoD, Myostatin, MuRF1, MAFbx, α-SMA, Collagen I, Smad2, and AKT. In addition, HE and Masson staining were used to assess muscle tissue damage in mice.

RESULTS

The level of Follistatin in Exo was significantly higher than that in UMSCs. UMSCs-Exo increased the levels of Follistatin, MyHC, MyoD, and p-Smad2 and decreased the levels of Myostatin, MuRF1, MAFbx, α-SMA, Collagen I, p-AKT, and p-mTOR in mice or C2C12 cells. In addition, UMSCs-Exo decreased levels of inflammation and fibrosis in mice. However, UMSCs-Exo-si-Follistatin reversed the effect of UMSCs-Exo. Transfection of oe-Smad2 up-regulated the protein levels of Collagen I, α-SMA, and changed the ratio of p-Smad2/Smad2 expression to 0.33, and 0.34, 0.73. LY294002 decreased the levels of MyHC, MyoD, and the ratio of p-AKT/AKT and p-mTOR/mTOR expression to 0.12, 0.17, 0.33, and 0.41, increased the levels of MuRF1 and MAFbx to 0.36 and 0.34.

CONCLUSION

This study demonstrated that Follistatin in UMSCs-Exo inhibits fibrosis and promotes muscle regeneration in mice by regulating Smad and AKT signaling.

The possible pathogenesis of liver fibrosis: therapeutic potential of natural polyphenols

Liver fibrosis is the formation of a fibrous scar resulting from chronic liver injury, independently from etiology. Although many of the mechanical details remain unknown, activation of hepatic stellate cells (HSCs) is a central driver of liver fibrosis. Extracellular mechanisms such as apoptotic bodies, paracrine stimuli, inflammation, and oxidative stress are critical in activating HSCs. The potential for liver fibrosis to reverse after removing the causative agent has heightened interest in developing antifibrotic therapies. Polyphenols, the secondary plant metabolites, have gained attention because of their health-beneficial properties, including well-recognized antioxidant and anti-inflammatory activities, in the setting of liver fibrosis. In this review, we present an overview of the mechanisms underlying liver fibrosis with a specific focus on the activation of resident HSCs. We highlight the therapeutic potential and promising role of natural polyphenols to mitigate liver fibrosis pathogenesis, focusing on HSCs activation. We also discuss the translational gap from preclinical findings to clinical treatments involved in natural polyphenols in liver fibrosis.

Digital pathology with artificial intelligence analysis provides insight to the efficacy of anti-fibrotic compounds in human 3D MASH model

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe liver disease characterized by lipid accumulation, inflammation and fibrosis. The development of MASH therapies has been hindered by the lack of human translational models and limitations of analysis techniques for fibrosis. The MASH three-dimensional (3D) InSight™ human liver microtissue (hLiMT) model recapitulates pathophysiological features of the disease. We established an algorithm for automated phenotypic quantification of fibrosis of Sirius Red stained histology sections of MASH hLiMTs model using a digital pathology quantitative single-fiber artificial intelligence (AI) FibroNest™ image analysis platform. The FibroNest™ algorithm for MASH hLiMTs was validated using anti-fibrotic reference compounds with different therapeutic modalities-ALK5i and anti-TGF-β antibody. The phenotypic quantification of fibrosis demonstrated that both reference compounds decreased the deposition of fibrillated collagens in alignment with effects on the secretion of pro-collagen type I/III, tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-3 and pro-fibrotic gene expression. In contrast, clinical compounds, Firsocostat and Selonsertib, alone and in combination showed strong anti-fibrotic effects on the deposition of collagen fibers, however less pronounced on the secretion of pro-fibrotic biomarkers. In summary, the phenotypic quantification of fibrosis of MASH hLiMTs combined with secretion of pro-fibrotic biomarkers and transcriptomics represents a promising drug discovery tool for assessing anti-fibrotic compounds.

Non-invasive markers of inflammation in alcohol-associated liver disease: A scoping review

Clinical manifestations of liver inflammation in alcohol-associated liver disease (ALD) can range from asymptomatic to severe alcoholic hepatitis. While biopsy is the gold standard for identifying liver inflammation, it is an invasive procedure with risks of bleeding, visceral damage, and infection. We aim to establish the state of the current literature on non-invasive markers of inflammation in ALD. We searched Ovid MEDLINE, Embase, and the Cochrane Library for original studies on the association between one or more non-invasive biomarker(s) and histological inflammation or hepatitis in ALD patients. Exclusion criteria were lack of histological data, abstract only, non-English-language articles, and animal studies. Two independent reviewers screened abstracts, reviewed full texts, and extracted data from included papers. Our search identified 8051 unique studies. Title and abstract screening resulted in 563 studies, and full-text screening resulted in 31 studies for final inclusion. The majority were single-center observational cohorts with an average sample size of 124. Review of these studies identified 44 unique biomarkers and 8 calculated scores associated with histological inflammation and/or hepatitis, in addition to a metabolomic panel of 468 metabolites. Six studies examined diagnostic accuracy for histological inflammation and/or hepatitis. The highest area under the receiver operating characteristic curve was 0.932 using a model based on four metabolites. This review highlights the available literature on non-invasive markers of inflammation in ALD. There is a dearth of studies that evaluate the diagnostic accuracy of these biomarkers, and larger studies are needed to confirm findings identified in small cohorts.

Decellularization Techniques for Tissue Engineering: Towards Replicating Native Extracellular Matrix Architecture in Liver Regeneration

The process of tissue regeneration requires the utilization of a scaffold, which serves as a structural framework facilitating cellular adhesion, proliferation, and migration within a physical environment. The primary aim of scaffolds in tissue engineering is to mimic the structural and functional properties of the extracellular matrix (ECM) in the target tissue. The construction of scaffolds that accurately mimic the architecture of the extracellular matrix (ECM) is a challenging task, primarily due to the intricate structural nature and complex composition of the ECM. The technique of decellularization has gained significant attention in the field of tissue regeneration because of its ability to produce natural scaffolds by removing cellular and genetic components from the extracellular matrix (ECM) while preserving its structural integrity. The present study aims to investigate the various decellularization techniques employed for the purpose of isolating the extracellular matrix (ECM) from its native tissue. Additionally, a comprehensive comparison of these methods will be presented, highlighting their respective advantages and disadvantages. The primary objective of this study is to gain a comprehensive understanding of the anatomical and functional features of the native liver, as well as the prevalence and impact of liver diseases. Additionally, this study aims to identify the limitations and difficulties associated with existing therapeutic methods for liver diseases. Furthermore, the study explores the potential of tissue engineering techniques in addressing these challenges and enhancing liver performance. By investigating these aspects, this research field aims to contribute to the advancement of liver disease treatment and management.

Biomarkers of Type IV Collagen Turnover Reflect Disease Activity in Patients with Early-Stage Non-Alcoholic Fatty Liver (NAFL)

BACKGROUND

Identification of progressive liver disease necessitates the finding of novel non-invasive methods to identify and monitor patients in need of early intervention. Investigating patients with early-liver injury may help identify unique biomarkers. Early-liver injury is characterized by remodeling of the hepatocyte basement membrane (BM) of the extracellular matrix. Thus, we quantified biomarkers targeting two distinct neo-epitopes of the major BM collagen, type IV collagen (PRO-C4 and C4M), in patients spanning the non-alcoholic fatty liver disease (NAFLD) spectrum.

METHODS

We evaluated PRO-C4 and C4M in a cross-sectional study with 97 patients with NAFLD confirmed on histology. Serological levels of PRO-C4 and C4M were quantified using validated competitive enzyme-linked immunosorbent assays (ELISA). Using the fatty liver inhibition of progression (FLIP) algorithm, we stratified patients into two groups: non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Biomarker levels were investigated in the two groups in patients stratified by the NAFLD activity score (NAS). In both groups, biomarker measurements were analyzed in relation to histological scorings of steatosis, inflammation, ballooning, and fibrosis.

RESULTS

Patients had a body mass index (BMI) of 30.9 ± 5.6 kg/m2, age of 53 ± 13 years and a NAS range of 1-8. Upon stratification by FLIP, the NASH patients had higher platelets, ALT, and AST levels than the NAFL group. Both PRO-C4 (p = 0.0125) and C4M (p = 0.003) increased with increasing NAS solely within the NAFL group; however, a large variability was present in the NASH group. Furthermore, both markers were significantly associated with lobular inflammation (p = 0.020 and p = 0.048) and steatosis (p = 0.004 and p = 0.015) in patients with NAFL.

CONCLUSIONS

This study found that type IV collagen turnover increased with the increase in NAS in patients with NAFL; however, this was not the case in patients with NASH. These findings support the assessments of the BM turnover using biomarkers in patients with early-disease development. These biomarkers may be used to track specific processes involved in the early pathobiology of NAFL.

PRO-C3 is a predictor of clinical outcomes in distinct cohorts of patients with advanced liver disease

Background & Aims

Fibroblast activity is a key feature of fibrosis progression and organ function loss, leading to liver-related complications and mortality. The fibrogenesis marker, PRO-C3, has been shown to have prognostic significance in relation to fibrosis progression and as a treatment efficacy marker. We investigated whether PRO-C3 was prognostic for clinical outcome and mortality in two distinct cohorts of compensated cirrhosis.

Methods

Cohort 1 was a rapid fibrosis progression cohort including 104 patients with HCV and biopsy-proven Ishak fibrosis stage ≥3 without prior clinical events. Cohort 2 was a prospective cohort including 172 patients with compensated cirrhosis of mixed aetiology. Patients were assessed for clinical outcomes. PRO-C3 was assessed in serum at baseline in cohorts 1 and 2, and compared with model for end-stage liver disease and albumin-bilirubin (ALBI) scores.

Results

In cohort 1, a 2-fold increase in PRO-C3 was associated with 2.7-fold increased hazard of liver-related events (95% CI 1.6-4.6), whereas a one unit increase in ALBI score was associated with a 6.5-fold increased hazard (95% CI 2.9-14.6). In cohort 2, a 2-fold increase in PRO-C3 was associated with a 2.7-fold increased hazard (95% CI 1.8-3.9), whereas a one unit increase in ALBI score was associated with a 6.3-fold increased hazard (95% CI 3.0-13.2). A multivariable Cox regression analysis identified PRO-C3 and ALBI as being independently associated with the hazard of liver-related outcomes.

Conclusions

PRO-C3 and ALBI were independent prognostic factors for predicting liver-related clinical outcomes. Understanding the dynamic range of PRO-C3 might enhance its use for both drug development and clinical practice.

Impact and Implications

We tested novel proteins of liver scarring (PRO-C3) in two groups of liver patients with advanced disease to see if they could predict clinical events. We found that this marker and an established test called ALBI were both independently associated with future liver-related clinical outcomes.

Validation of scores of PRO-C3 to predict liver-related events in alcohol-related liver disease

BACKGROUND AND AIMS

Risk prediction in alcohol-related liver disease (ArLD) is an unmet need. We aimed to assess PRO-C3 models to predict liver-related events (LRE) in patients with a history of excessive alcohol use without an established diagnosis of chronic liver disease.

METHODS

A prospective cohort study of 462 patients with ArLD, split into a derivation cohort of 221 secondary care patients and a validation cohort of 241 primary care patients. Baseline variables, including fibrogenesis marker PRO-C3, were used to develop a prediction model. Prognostic accuracy was compared to enhanced liver fibrosis (ELF), fibrosis-4-index (FIB-4), transient elastography (TE) and ADAPT.

RESULTS

In the derivation and validation cohorts, 67 (30%) and 19 (8%) experienced an LRE during a median follow-up of 5.2 years (IQR: 3.2-6.8) and 4.0 years (IQR: 2.7-5.6). On top of PRO-C3 and ADAPT score, we generated a model (ALPACA) of independent predictors of LREs (PRO-C3, AST/ALT, platelets). ALPACA had high prognostic accuracy with a C-statistic of 0.85 in the derivation cohort, comparable to ELF (0.83) and TE (0.84) and significantly higher than FIB-4 (0.78), PRO-C3 (0.80) and ADAPT (0.81). In the validation cohort, all tests had comparable C-statistics. Compared to low-risk patients (ALPACA ≤11), high-risk patients (>11) had a subhazard ratio for LREs of 12.6 (95% CI 5.9-26.8, p < .001) and higher cumulative incidence (57% vs. 7%, p < .001; derivation cohort). We observed similar subhazard ratio in the validation cohort.

CONCLUSIONS

PRO-C3-based scores are reliable tools to predict LREs in ArLD patients and are suitable for risk stratification in primary and secondary care.

Matrix metalloproteinases induce extracellular matrix degradation through various pathways to alleviate hepatic fibrosis

Liver fibrosis is the common consequence of various chronic liver injuries and is mainly characterized by the imbalance between the production and degradation of extracellular matrix, which leads to the accumulation of interstitial collagen and other matrix components. Matrix metalloproteinases (MMPs) and their specific inhibitors, that is, tissue inhibitors of metalloproteinases (TIMPs), play a crucial role in collagen synthesis and lysis. Previous in vivo and in vitro studies of our laboratory found repressing extracellular matrix (ECM) accumulation by restoring the balance between MMPs and TIMPs can alleviate liver fibrosis. We conducted a review of articles published in PubMed and Science Direct in the last decade until February 1, 2023, which were searched for using these words "MMPs/TIMPs" and "Hepatic Fibrosis." Through a literature review, this article reviews the experimental studies of liver fibrosis based on MMPs/TIMPs, summarizes the components that may exert an anti-liver fibrosis effect by affecting the expression or activity of MMPs/TIMPs, and attempts to clarify the mechanism of MMPs/TIMPs in regulating collagen homeostasis, so as to provide support for the development of anti-liver fibrosis drugs. We found the MMP-TIMP-ECM interaction can result in better understanding of the pathogenesis and progression of hepatic fibrosis from a different angle, and targeting this interaction may be a promising therapeutic strategy for hepatic fibrosis. Additionally, we summarized and analyzed the drugs that have been found to reduce liver fibrosis by changing the ratio of MMPs/TIMPs, including medicine natural products.

Mechanical homeostasis imbalance in hepatic stellate cells activation and hepatic fibrosis

Chronic liver disease or repeated damage to hepatocytes can give rise to hepatic fibrosis. Hepatic fibrosis (HF) is a pathological process of excessive sedimentation of extracellular matrix (ECM) proteins such as collagens, glycoproteins, and proteoglycans (PGs) in the hepatic parenchyma. Changes in the composition of the ECM lead to the stiffness of the matrix that destroys its inherent mechanical homeostasis, and a mechanical homeostasis imbalance activates hepatic stellate cells (HSCs) into myofibroblasts, which can overproliferate and secrete large amounts of ECM proteins. Excessive ECM proteins are gradually deposited in the Disse gap, and matrix regeneration fails, which further leads to changes in ECM components and an increase in stiffness, forming a vicious cycle. These processes promote the occurrence and development of hepatic fibrosis. In this review, the dynamic process of ECM remodeling of HF and the activation of HSCs into mechanotransduction signaling pathways for myofibroblasts to participate in HF are discussed. These mechanotransduction signaling pathways may have potential therapeutic targets for repairing or reversing fibrosis.

Damaged collagen detected by collagen hybridizing peptide as efficient diagnosis marker for early hepatic fibrosis

Liver fibrosis is characterized by excessive synthesis and deposition of extracellular matrix (ECM) in liver tissues. However, it still has been lacking of early detection and diagnosis methods. The collagen hybridizing peptide (CHP) is a novel synthetic peptide that enables detection of collagen damage and tissue remodeling. Here, we showed that obvious CHP-positive staining could be detected in the liver while given CCl₄ for only 3 days, which was significantly enhanced while given CCl₄ for 7 days. However, H&E staining showed no significant changes in fibrous tissue, and sirius red-positive staining could only be observed while given CCl₄ for 14 days. Moreover, CHP-positive staining enhanced initially at portal area which further extended into the hepatic lobule, which was increased more significantly than sirius red-positive staining in the model of 10 and 14 days. Further proteomic analysis of CHP-positive staining revealed that pathways associated with ECM remodeling were significantly increased, while retinol metabolism was downregulated. Meanwhile, proteins enriched in cellular gene transcription and signal transduction involved in fibrogenesis were also upregulated, suggesting that fibrosis occurred in CHP-positive staining. Our study provided evidence that CHP could detect the collagen damage in liver, which might be an efficient indicator for the diagnosis of liver fibrosis at a very early stage.

Collagen matrix scaffolds: Future perspectives for the management of chronic liver diseases

Approximately 1.5 billion chronic liver disease (CLD) cases have been estimated worldwide, encompassing a wide range of liver damage severities. Moreover, liver disease causes approximately 1.75 million deaths per year. CLD is typically characterized by the silent and progressive deterioration of liver parenchyma due to an incessant inflammatory process, cell death, over deposition of extracellular matrix proteins, and dysregulated regeneration. Overall, these processes impair the correct function of this vital organ. Cirrhosis and liver cancer are the main complications of CLD, which accounts for 3.5% of all deaths worldwide. Liver transplantation is the optimal therapeutic option for advanced liver damage. The liver is one of the most common organs transplanted; however, only 10% of liver transplants are successful. In this context, regenerative medicine has made significant progress in the design of biomaterials, such as collagen matrix scaffolds, to address the limitations of organ transplantation (e.g., low donation rates and biocompatibility). Thus, it remains crucial to continue with experimental and clinical studies to validate the use of collagen matrix scaffolds in liver disease.

Identification of biomarkers co-associated with M1 macrophages, ferroptosis and cuproptosis in alcoholic hepatitis by bioinformatics and experimental verification

Backgrounds

Alcoholic hepatitis (AH) is a major health problem worldwide. There is increasing evidence that immune cells, iron metabolism and copper metabolism play important roles in the development of AH. We aimed to explore biomarkers that are co-associated with M1 macrophages, ferroptosis and cuproptosis in AH patients.

Methods

GSE28619 and GSE103580 datasets were integrated, CIBERSORT algorithm was used to analyze the infiltration of 22 types of immune cells and GSVA algorithm was used to calculate ferroptosis and cuproptosis scores. Using the "WGCNA" R package, we established a gene co-expression network and analyzed the correlation between M1 macrophages, ferroptosis and cuproptosis scores and module characteristic genes. Subsequently, candidate genes were screened by WGCNA and differential expression gene analysis. The LASSO-SVM analysis was used to identify biomarkers co-associated with M1 macrophages, ferroptosis and cuproptosis. Finally, we validated these potential biomarkers using GEO datasets (GSE155907, GSE142530 and GSE97234) and a mouse model of AH.

Results

The infiltration level of M1 macrophages was significantly increased in AH patients. Ferroptosis and cuproptosis scores were also increased in AH patients. In addition, M1 macrophages, ferroptosis and cuproptosis were positively correlated with each other. Combining bioinformatics analysis with a mouse model of AH, we found that ALDOA, COL3A1, LUM, THBS2 and TIMP1 may be potential biomarkers co-associated with M1 macrophages, ferroptosis and cuproptosis in AH patients.

Conclusion

We identified 5 potential biomarkers that are promising new targets for the treatment and diagnosis of AH patients.

Novel potential biomarkers for severe alcoholic liver disease

Background

Alcoholic liver disease (ALD) is a leading cause of advanced liver disease; however, minor clinical symptoms in the early stage frequently result in delayed diagnosis and therapy. Invasive liver biopsy, the gold standard for diagnosing ALD, is unsuitable for repetitive analysis. This study aims to identify potential serum biomarkers that could contribute to non-invasive disease screening and monitoring.

Methods

Label-free LC-MS/MS quantitative proteomics analysis was performed to identify differentially expressed proteins in the discovery cohort, followed by bioinformatics analysis based on the KEGG, GO, and String databases. Prioritized proteins were validated subsequently by quantitative assays. The area under the receiver operating characteristic curve (AUROC) was used to assess the diagnosis performance of potential biomarkers.

Results

A total of 161 differentially expressed proteins were identified in the discovery cohort, of which 123 were up-regulated and 38 were down-regulated. B2M, IGFALS, and IGFBP3 were evaluated, and all demonstrated excellent diagnosis performance with AUROCs of over 0.9 when distinguishing patients with severe ALD from healthy controls. The AUROC values of B2M, IGFBP3, and IGFALS were 0.7131, 0.8877, and 0.9896 for differentiating severe ALD from non-severe ALD to indicate disease severity. B2M could distinguish patients with non-severe ALD and HC participants with an AUROC value of 0.8985. The efficiency of multiple combinations of these biomarkers was superior to that of the existing liver fibrosis evaluation indices used to monitor disease progression, with AUROC values of over 0.9. IGFALS showed a positive correlation with ALT/AST (r=0.4648, P=0.0009) and may be developed as a therapeutic target.

Conclusion

This proteomic study identified three novel candidate proteins as promising circulating biomarkers for clinical diagnosis and disease progression and also provided the proteomic atlas for ALD pathophysiological mechanisms.

Noninvasive proteomic biomarkers for alcohol-related liver disease

Alcohol-related liver disease (ALD) is a major cause of liver-related death worldwide, yet understanding of the three key pathological features of the disease-fibrosis, inflammation and steatosis-remains incomplete. Here, we present a paired liver-plasma proteomics approach to infer molecular pathophysiology and to explore the diagnostic and prognostic capability of plasma proteomics in 596 individuals (137 controls and 459 individuals with ALD), 360 of whom had biopsy-based histological assessment. We analyzed all plasma samples and 79 liver biopsies using a mass spectrometry (MS)-based proteomics workflow with short gradient times and an enhanced, data-independent acquisition scheme in only 3 weeks of measurement time. In plasma and liver biopsy tissues, metabolic functions were downregulated whereas fibrosis-associated signaling and immune responses were upregulated. Machine learning models identified proteomics biomarker panels that detected significant fibrosis (receiver operating characteristic-area under the curve (ROC-AUC), 0.92, accuracy, 0.82) and mild inflammation (ROC-AUC, 0.87, accuracy, 0.79) more accurately than existing clinical assays (DeLong's test, P < 0.05). These biomarker panels were found to be accurate in prediction of future liver-related events and all-cause mortality, with a Harrell's C-index of 0.90 and 0.79, respectively. An independent validation cohort reproduced the diagnostic model performance, laying the foundation for routine MS-based liver disease testing.

Diagnostic challenges in patients with alcohol-related liver disease

Alcohol is globally the leading risk factor for cirrhosis and is subsumed under the term alcohol-related liver disease (ALD). However, only ca. 10% of people with harmful alcohol consumption (>40 gram alcohol per day) develop cirrhosis, while 15% have normal liver histology. Unfortunately, laboratory parameters and ultrasound hold little value to neither rule-in nor rule out alcohol related liver fibrosis. While several indices with combinations of liver associated markers such as FIB4 seem to be promising, non-invasive test strategies are urgently needed with cut-off's that can be applied to guide clinical decision making. The aims of this review article are to highlight novel developments for the diagnosis of ALD and to identify topics of controversy and potential future directions. In the last 15 years, elastography to measure liver stiffness (LS) has significantly improved our screening strategies for cirrhosis. LS values below 6 kPa are considered as normal and exclude ALD. LS of 8 and 12.5 kPa represent generally accepted cut-off values for F3 and F4 fibrosis. Especially, transient elastography (TE) has been assessed in numerous studies, but similar performance can be obtained with point shear wave elastography, 2 SD shear wave elastography or MR elastography. Important confounders of elevated LS such as inflammation should also be considered and alcohol withdrawal not only improves liver inflammation but also LS. Liver stiffness measurement has signficiantly improved early diagnosis and follow-up of fibrosis in patients with ALD and patients with diagnosed manifest but clinically compensated cirrhosis should undergo further clinical examinations to rule out complications of portal hypertension. In addition, surveillance for the occurrence of hepatocellular carcinoma is recommended in all cirrhotic patients.

Binge drinking induces an acute burst of markers of hepatic fibrogenesis (PRO-C3)

BACKGROUND & AIMS

Binge drinking is associated with an increased risk of liver disease. Morbidity and mortality of alcohol-related liver disease (ALD) is associated with collagen deposition in the hepatic extracellular matrix (ECM). However, the acute effects of binge drinking on ECM turnover are unknown. We aimed to investigate the effects on hepatic ECM turnover following a binge drinking episode.

METHODS

We performed a pathophysiological intervention study with 15 non-alcoholic fatty liver disease (NAFLD) patients, 15 ALD patients and 10 healthy controls. We used 40% ethanol in 9 mg/mL NaCl administered through a nasogastric tube to simulate binge drinking. Hepatic vein catheterisation allowed simultaneous hepatic- and systemic vein sampling. Markers of ECM formation and degradation were measured with competitive ELISA.

RESULTS

The interstitial matrix formation marker PRO-C3 increased by 1.2 ng/mL (10%, P < .001) 24 hours after binge drinking. In participants with existing liver fibrosis determined by elevated baseline PRO-C3, hepatic levels increased by 0.09 ng/mL (95% CI: 0.03-0.15, P = .005) while systemic PRO-C3 decreased 0.11 ng/mL (95% CI: -0.15 to -0.06, P < .001) in 3 hours. PRO-C8 increased by 30% (+0.9 ng/mL, P = .014) in liver-diseased patients with F0-F1 but not in any other group. Twenty-four-hour changes in systemic C3M and PRO-C3 were not associated (P = .911).

CONCLUSIONS

Binge drinking induced an acute burst of PRO-C3 in healthy individuals and patients with liver disease. Markers of ECM degradation were not correlated to markers of ECM formation, suggesting that even a single episode of binge drinking promotes excessive hepatic fibrogenesis.