Systemic Galectin-3 in Smokers with Chronic Obstructive Pulmonary Disease and Chronic Bronchitis: The Impact of Exacerbations

Emerging Roles of Galectin-3 in Pulmonary Diseases

Galectin-3 is a multifunctional protein that is involved in various physiological and pathological events. Emerging evidence suggests that galectin-3 also plays a critical role in the pathogenesis of pulmonary diseases. Galectin-3 can be produced and secreted by various cell types in the lungs, and the overexpression of galectin-3 has been found in acute lung injury/acute respiratory distress syndrome (ALI/ARDS), pulmonary hypertension (PH), pulmonary fibrosis diseases, lung cancer, lung infection, chronic obstructive pulmonary disease (COPD), and asthma. Galectin-3 exerts diverse effects on the inflammatory response, immune cell activation, fibrosis and tissue remodeling, and tumorigenesis in these pulmonary disorders, and genetic and pharmacologic modulation of galectin-3 has therapeutic effects on the treatment of pulmonary illnesses. In this review, we summarize the structure and function of galectin-3 and the underlying mechanisms of galectin-3 in pulmonary disease pathologies; we also discuss preclinical and clinical evidence regarding the therapeutic potential of galectin-3 inhibitors in these pulmonary disorders. Additionally, targeting galectin-3 may be a very promising therapeutic approach for the treatment of pulmonary diseases.

Association between Galectin-13 Expression and Eosinophilic Airway Inflammation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) and asthma are chronic inflammatory diseases of the airways. Galectin-13 has recently been forwarded as a biomarker for airway eosinophilic inflammation in asthma. However, the association between galectin-13 and COPD remains unknown. To examine the changes in galectin-13 expression in acute exacerbations of COPD (AECOPD) and the stable phase of COPD and unveil the association between galectin-13 expression and eosinophilic inflammation in COPD, we measured plasma galectin-13 expression in different phases of COPD patients (n = 60, 44 AECOPD patients, and 16 stable COPD patients) and healthy controls (n = 15). Plasma levels of galectin-13 in 60 COPD patients were further analyzed and compared to systemic inflammation, airway eosinophilic inflammation, and lung function. The plasma galectin-13 level was markedly increased in subjects with AECOPD compared to stable COPD patients and healthy controls. Plasma galectin-13 levels in COPD subjects were positively correlated with serum CRP (r_s = 0.46, p = 0.0003), peripheral blood eosinophilia count (r_s = 0.57, p<0.0001), and FeNO (r_s = 0.46, p = 0.0002). In addition, the level of galectin-13 was negatively correlated with FEV₁ (r_s = -0.43, p = 0.0001), FEV₁ pred (%) (r_s = -0.544, p<0.0001), as well as FEV₁/FVC (r_s = -0.46, p<0.0001). Multiple linear regression analysis suggested that plasma galectin-13 levels were affected by FEV₁ pred (%), peripheral blood eosinophilia count, and FeNO. We concluded that galectin-13 levels were increased in COPD patients, and elevated galectin-13 expressions related to airway eosinophilic inflammation. Galectin-13 may facilitate the identification of COPD endotypes and may become a potential therapeutic target.

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.

Serum Galectin-3 and Aldosterone: potential biomarkers of cardiac complications in patients with COVID-19

BACKGROUND

Despite severe acute respiratory syndrome (SARS)-Coronavirus (CoV2) primarily targeting the lungs, the heart represents another critical virus target. Thus, the identification of SARS-CoV-2 disease of 2019 (COVID-19)-associated biomarkers would be beneficial to stratify prognosis and the risk of developing cardiac complications. Aldosterone and galectin-3 promote fibrosis and inflammation and are considered a prognostic biomarker of lung and adverse cardiac remodeling. Here, we tested whether galectin-3 and aldosterone levels can predict adverse cardiac outcomes in COVID-19 patients.

METHODS

To this aim, we assessed galectin-3 and aldosterone serum levels in 51 patients diagnosed with COVID-19, using a population of 19 healthy subjects as controls. In in vitro studies, we employed 3T3 fibroblasts to assess the potential roles of aldosterone and galectin-3 in fibroblast activation.

RESULTS

Serum galectin-3 levels were more elevated in COVID-19 patients than healthy controls and correlated with COVID-19 severity classification and cardiac Troponin-I (cTnI) serum levels. Furthermore, we observed an augmented secretion of aldosterone in COVID-19 patients. This adrenal hormone is a direct stimulator of galectin-3 secretion; therefore, we surmised that this axis could perpetrate fibrosis and adverse remodeling in these subjects. Thus, we stimulated fibroblasts with 10% of serum from COVID-19 patients. This challenge markedly rose the expression of smooth muscle alpha (α)-2 actin (ACTA2), a myofibroblast marker.

CONCLUSIONS

Our study suggests that COVID-19 can affect cardiac structure and function by triggering aldosterone and galectin-3 release that may serve as prognostic and therapeutic biomarkers while monitoring the course of cardiac complications in patients suffering from COVID-19.

Chronic Obstructive Pulmonary Disease: Epidemiology, Biomarkers, and Paving the Way to Lung Cancer

Chronic obstructive pulmonary disease (COPD), the frequently fatal pathology of the respiratory tract, accounts for half a billion cases globally. COPD manifests via chronic inflammatory response to irritants, frequently to tobacco smoke. The progression of COPD from early onset to advanced disease leads to the loss of the alveolar wall, pulmonary hypertension, and fibrosis of the respiratory epithelium. Here, we focus on the epidemiology, progression, and biomarkers of COPD with a particular connection to lung cancer. Dissecting the cellular and molecular players in the progression of the disease, we aim to shed light on the role of smoking, which is responsible for the disease, or at least for the more severe symptoms and worse patient outcomes. We summarize the inflammatory conditions, as well as the role of EMT and fibroblasts in establishing a cancer-prone microenvironment, i.e., the soil for ‘COPD-derived’ lung cancer. We highlight that the major health problem of COPD can be alleviated via smoking cessation, early diagnosis, and abandonment of the usage of biomass fuels on a global basis.