Galectin-3 is overexpressed in advanced cirrhosis and predicts post-liver transplant infectious complications

Effect of GB1107, a novel galectin-3 inhibitor on pro-fibrotic signalling in the liver

BACKGROUND AND PURPOSE

Galectin-3 (Gal-3) is a pro-fibrotic β-galactoside binding lectin highly expressed in fibrotic liver and implicated in hepatic fibrosis. GB1107 is a novel orally active Gal-3 small molecule inhibitor that has high affinity for Gal-3 >1000-fold selectively over other galectins. The aim of this study was to characterise GB1107 and galectin-3 in vitro and in vivo in the context of fibrosis signalling and liver disease.

EXPERIMENTAL APPROACH

Liver fibrosis was induced by administration of CCl4 twice weekly by intraperitoneal injection in mice for 8 weeks. GB1107 was orally administered once daily (10 mg/kg) for the last 4 weeks of CCl4 treatment. Fibrosis was assessed by picrosirius red staining of FFPE sections. Liver enzymes, Gal-3 and downstream biomarkers were assessed in liver and plasma. Paired-end sequencing was performed on the NextSeq 2000 platform. Pathway enrichment analysis was performed to determine enrichment of differentially expressed genes (DEGs) within Reactome pathways and Gene Ontology (GO) terms.

KEY RESULTS

GB1107 significantly reduced plasma transaminases and liver Gal-3 and reduced liver fibrosis. RNAseq analysis of whole liver showed that 1,659 DEGs were identified with CCl4 treatment compared to control. Pathways enriched in up-regulated genes in the CCl4 group included those related to the extracellular matrix, collagen biosynthesis and assembly, cell cycle and the immune system. Comparing GB1107 treatment with CCl4 control 1147 DEGs were identified. GB1107 effectively reversed the majority of the CCl4 induced gene changes.

CONCLUSIONS AND IMPLICATIONS

GB1107 attenuated liver fibrosis and highlights Gal-3 as a therapeutic target for hepatic fibrosis.

Serum Galectin-3 as a Non-Invasive Marker for Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a serious liver disease associated with inflammatory bowel disease (IBD). Galectin-3, an inflammatory and fibrotic molecule, has elevated circulating levels in patients with chronic liver disease and inflammatory bowel disease (IBD). This study aims to clarify whether galectin-3 can differentiate between patients with IBD, PSC, and PSC-IBD. Our study measured serum galectin-3 levels in 38 healthy controls, 55 patients with IBD, and 22 patients with PSC (11 patients had underlying IBD and 11 patients did not), alongside the urinary galectin-3 of these patients and 18 controls. Serum and urinary galectin-3 levels in IBD patients were comparable to those in controls. Among IBD patients, those with high fecal calprotectin, indicating severe disease, exhibited lower serum and elevated urinary galectin-3 levels compared to those with low calprotectin levels. Serum galectin-3 levels were inversely correlated with C-reactive protein levels. PSC patients displayed higher serum and urinary galectin-3 levels than IBD patients, with the highest serum levels observed in PSC patients with coexisting IBD. There was no correlation between serum and urinary galectin-3 levels and laboratory indicators of liver injury in both IBD and PSC patients. In conclusion, this study demonstrates that serum and urinary galectin-3 levels can distinguish IBD from PSC patients, and also reveals higher serum galectin-3 levels in PSC-IBD patients compared to those with isolated PSC.

Galectin-3 in biliary atresia and other pediatric cholestatic liver diseases

AIMS

Biliary atresia (BA) is characterized by intrahepatic inflammation and rapid progression of liver fibrosis. Galectin-3, a beta-galactoside binding protein, is a key regulator of inflammation and fibrosis. The aim of this study was to characterize circulating and hepatic Galectin-3 levels in children with BA.

METHODS

Plasma and liver samples were obtained from children with early BA at time of Kasai hepatoportoenterostomy, late BA at time of transplant, early and late other cholestatic liver diseases (CLD), and controls. Plasma Galectin-3 was measured using standard enzyme-linked immunoassay. Liver tissue was analyzed with multiplex immunohistochemistry and quantified using whole slide analysis. Statistical comparisons were made using nonparametric testing.

RESULTS

Plasma Galectin-3 in late BA was significantly higher than in early BA (20.82 [12.45-30.46] vs. 11.30 [8.74-16.83] ng/mL, p = 0.0096). Galectin-3 levels correlated with markers of disease severity and interleukin-6. There were significantly more Galectin-3+ M2 macrophages in late BA in comparison to late other CLD (162 [157-233] vs. 49 [33-59] cells/mm2, p = 0.03). The number of Galectin-3+ M2 macrophages correlated with the number of activated hepatic stellate cells and bile duct proliferation.

CONCLUSIONS

Plasma Galectin-3 is higher in late BA at time of transplant in comparison to early BA at time of Kasai. The number of Galectin-3 expressing M2 macrophages in late BA is elevated relative to late other CLD and was associated with other prognostic histological findings. Galectin-3 targeted therapy may be beneficial in slowing disease progression to cirrhosis in children with BA.

Cigarette smoke-induced galectin-3 as a diagnostic biomarker and therapeutic target in lung tissue remodeling

Galectin-3 (Gal-3), a multifunctional carbohydrate-binding lectin, has emerged as a key player in various biological processes including inflammation, cancer, cardiovascular diseases and fibrotic disorders, however it remains unclear if Gal-3 is a bystander or drives lung tissue remodeling (LTR). Persistent exposure to cigarette smoke (CS) is the leading cause of oxidative and inflammatory damage to the lung tissues. CS-induced pathological increase in Gal-3 expression has been implicated in the pathogenesis of various respiratory conditions, such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and lung cancer. We and others have reported that CS induces Gal-3 synthesis and secretion, which modulates the pathological signaling pathways in lung epithelial cells implicating Gal-3 as a novel diagnostic marker and a factor driving LTR in CS-exposed lungs. Therefore, pharmacological interventions targeting Gal-3 and its upstream and downstream signaling pathways can help combat CS-induced LTR. Excitingly, preclinical models have demonstrated the efficacy of interventions such as Gal-3 expression inhibition, Gal-3 receptor blockade, and signaling pathways modulation open up promising avenues for future therapeutic interventions. Furthermore, targeting extracellular vesicles-mediated Gal-3 release and the potential of microRNA-based therapy are emerging as novel therapeutic approaches in CS-induced LTR and have been discussed in this article.

Evaluation of right ventricular diastolic function, systolic function, and circulating galectin-3 concentrations in dogs with pulmonary stenosis

BACKGROUND

Cardiovascular diseases with increased right ventricular (RV) afterload induce RV diastolic and systolic dysfunction, and myocardial fibrosis in humans. Studies in dogs with pulmonary stenosis (PS) evaluating RV diastolic function and markers of myocardial fibrosis are lacking.

HYPOTHESIS/OBJECTIVES

Dogs with PS have echocardiographic evidence of RV diastolic and systolic dysfunction and increased serum concentrations of galectin-3 (Gal-3), a surrogate biomarker for myocardial fibrosis.

ANIMALS

Forty client-owned dogs (10 controls, 30 with PS).

METHODS

Prospective study. All dogs had systemic blood pressure measurement, serum biochemical analysis, echocardiography, and measurement of serum Gal-3 concentration performed.

RESULTS

Variables of RV diastolic function were obtained in 39/40 dogs. Trans-tricuspid flow velocity in early diastole to trans-tricuspid flow velocity in late diastole ratios (RV E/A) were lower (P < .001) in dogs with PS (median, 0.94; range, 0.62-2.04) compared to controls (1.78; 1.17-2.35). Trans-tricuspid flow velocity in early diastole to tricuspid annular myocardial velocity in early diastole ratios (RV E/e') were higher (P < .001) in dogs with PS (11.55; 4.69-28) compared to control (6.21; 5.16-7.21). Variables of RV systolic function were lower in dogs with PS (P = <.001). Serum Gal-3 concentration was higher (P = .002) in dogs with PS (285.1 pg/mL; 94.71-406.97) compared to control dogs (162.83 pg/mL; 52.3-232.82).

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with PS have RV diastolic and systolic dysfunction, and increased Gal-3 concentrations. These findings suggest the presence of RV myocardial fibrosis in dogs with PS, which could impact clinical management.

Insights into the Role of Galectin-3 as a Diagnostic and Prognostic Biomarker of Atrial Fibrillation

Atrial fibrillation (AF) is an irregular atrial activity and the most prevalent type of arrhythmia. Although AF is easily diagnosed with an electrocardiogram, there is a keen interest in identifying an easy-to-dose biomarker that can predict the prognosis of AF and its recurrence. Galectin-3 (Gal-3) is a beta-galactoside binding protein from the lectin family with pro-fibrotic and -inflammatory effects and a pivotal role in a variety of biological processes, cell proliferation, and differentiation; therefore, it is implicated in the pathogenesis of many cardiovascular (e.g., heart failure (HF)) and noncardiovascular diseases. However, its specificity and sensitivity as a potential marker in AF patients remain debated and controversial. This article comprehensively reviewed the evidence regarding the interplay between Gal-3 and patients with AF. Clinical implications of measuring Gal-3 in AF patients for diagnosis and prognosis are mentioned. Moreover, the role of Gal-3 as a potential biomarker for the management of AF recurrence is investigated. The association of Gal-3 and AF in special populations (coronary artery disease, HF, metabolic syndrome, chronic kidney disease, and diabetes mellitus) has been explored in this review. Overall, although further studies are needed to enlighten the role of Gal-3 in the diagnosis and treatment of AF, our study demonstrated the high potential of this molecule to be used and focused on by researchers and clinicians.

Galectin-3: therapeutic targeting in liver disease

INTRODUCTION

The rising incidence of liver diseases is a worldwide healthcare concern. However, the therapeutic options to manage chronic inflammation and fibrosis, the processes at the basis of morbidity and mortality of liver diseases, are very limited. Galectin 3 (Gal-3) is a protein implicated in fibrosis in multiple organs. Several Gal-3 inhibitors are currently in clinical development.

AREAS COVERED

This review describes our current understanding of the role of Gal-3 in chronic liver diseases, with special emphasis on fibrosis. Also, we review therapeutic advances based on Gal-3 inhibition, describing drug properties and their current status in clinical research.

EXPERT OPINION

Currently, the known effects of Gal-3 point to a direct activation of the NLRP3 inflammasome leading to its activation in liver macrophages and activated macrophages play a key role in tissue fibrogenesis. However, more research is needed to elucidate the role of Gal-3 in the different activation pathways, dissecting the intracellular and extracellular mechanisms of Gal-3, and its role in pathogenesis. Gal-3 could be a target for early therapy of numerous hepatic diseases and, given the lack of therapeutic options for liver fibrosis, there is a strong pharmacologic potential for Gal-3-based therapies.

Treatment of liver fibrosis: Past, current, and future

Liver fibrosis accompanies the progression of chronic liver diseases independent of etiologies, such as hepatitis viral infection, alcohol consumption, and metabolic-associated fatty liver disease. It is commonly associated with liver injury, inflammation, and cell death. Liver fibrosis is characterized by abnormal accumulation of extracellular matrix components that are expressed by liver myofibroblasts such as collagens and alpha-smooth actin proteins. Activated hepatic stellate cells contribute to the major population of myofibroblasts. Many treatments for liver fibrosis have been investigated in clinical trials, including dietary supplementation (e.g., vitamin C), biological treatment (e.g., simtuzumab), drug (e.g., pegbelfermin and natural herbs), genetic regulation (e.g., non-coding RNAs), and transplantation of stem cells (e.g., hematopoietic stem cells). However, none of these treatments has been approved by Food and Drug Administration. The treatment efficacy can be evaluated by histological staining methods, imaging methods, and serum biomarkers, as well as fibrosis scoring systems, such as fibrosis-4 index, aspartate aminotransferase to platelet ratio, and non-alcoholic fatty liver disease fibrosis score. Furthermore, the reverse of liver fibrosis is slowly and frequently impossible for advanced fibrosis or cirrhosis. To avoid the life-threatening stage of liver fibrosis, anti-fibrotic treatments, especially for combined behavior prevention, biological treatment, drugs or herb medicines, and dietary regulation are needed. This review summarizes the past studies and current and future treatments for liver fibrosis.

Galectin-3 inhibition as a potential therapeutic target in non-alcoholic steatohepatitis liver fibrosis

Nonalcoholic fatty liver disease continues to be one of the major health challenges facing the world, with estimates of non-alcoholic steatohepatitis (NASH) prevalence in over 25 percent of the world’s population. NASH represents a spectrum of disease that may lead to hepatic fibrosis and eventual cirrhosis, with the risk of cirrhosis decompensation, and hepatocellular carcinoma. New therapies are desperately needed for NASH, especially for later stages of fibrosis and cirrhosis. Galectin-3 inhibition is being explored as a new liver antifibrotic therapy. This concise review will outline the state of the art of this new therapeutic target.

Liver transplantation is beneficial regardless of cirrhosis stage or acute-on-chronic liver failure grade: A single-center experience

BACKGROUND

Liver transplantation for the most critically ill remains controversial; however, it is currently the only curative treatment option.

AIM

To assess immediate posttransplant outcomes and compare the short (1 year) and long-term (6 years) posttransplant survival among cirrhotic patients stratified by disease severity.

METHODS

We included cirrhotic patients undergoing liver transplantation between 2015 and 2019 and categorized them into compensated cirrhosis (CC), decompensated cirrhosis (DC), and acute-on-chronic liver failure (ACLF). ACLF was further divided into severity grades. Our primary outcomes of interest were total days of intensive care unit (ICU) and hospital stay, development of complications and posttransplant survival at 1 and 6 years.

RESULTS

235 patients underwent liver transplantation (CC = 11, DC = 129 and ACLF = 95). Patients with ACLF had a significantly longer hospital stay [8.0 (6.0-13.0) vs CC, 6.0 (3.0-7.0), and DC 7.0 (4.5-10.0); P = 0.01] and developed more infection-related complications [47 (49.5%), vs CC, 1 (9.1%) and DC, 38 (29.5%); P < 0.01]. Posttransplant survival at 1- and 6-years was similar among groups (P = 0.60 and P = 0.90, respectively). ACLF patients stratified according to ACLF grade [ACLF-1 n = 40 (42.1%), ACLF-2 n = 33 (34.7%) and ACLF-3 n = 22 (23.2%)], had similar ICU and hospital stay length (P = 0.68, P = 0.54), as well as comparable frequencies of overall and infectious post-transplant complications (P = 0.58, P = 0.80). There was no survival difference between ACLF grades at 1 year and 6 years (P = 0.40 and P = 0.15).

CONCLUSION

Patients may benefit from liver transplantation regardless of the cirrhosis stage. ACLF patients have a longer hospital stay and frequency of infectious complications; however, excellent, and comparable 1 and 6-year survival rates support their enlisting and transplantation including those with ACLF-3.

Spotlight on liver macrophages for halting liver disease progression and injury

INTRODUCTION

Over the past two decades, understanding of hepatic macrophage biology has provided astounding details of their role in the progression and regression of liver diseases. The hepatic macrophages constitute resident macrophages, Kupffer cells, and circulating bone marrow monocyte-derived macrophages, which play a diverse role in liver injury and repair. Imbalance in the macrophage population leads to pathological consequences and is responsible for the initiation and progression of acute and chronic liver injuries. Further, distinct populations of hepatic macrophages and their high heterogeneity make their complex role enigmatic. The unique features of distinct phenotypes of macrophages have provided novel biomarkers for defining the stages of liver diseases. The distinct mechanisms of hepatic macrophages polarization and recruitment have been at the fore front of research. In addition, the secretome of hepatic macrophages and their immune regulation has provided clinically relevant therapeutic targets.

AREAS COVERED

Herein we have highlighted the current understanding in the area of hepatic macrophages, and their role in the progression of liver injury.

EXPERT OPINION

It is essential to ascertain the physiological and pathological role of evolutionarily conserved distinct macrophage phenotypes in different liver diseases before viable approaches may see a clinical translation.