Expression of ectopic trypsin in atherosclerotic plaques and the effects of aprotinin on plaque stability

Aprotinin-Drug against Respiratory Diseases

Aprotinin (APR) was discovered in 1930. APR is an effective pan-protease inhibitor, a typical "magic shotgun". Until 2007, APR was widely used as an antithrombotic and anti-inflammatory drug in cardiac and noncardiac surgeries for reduction of bleeding and thus limiting the need for blood transfusion. The ability of APR to inhibit proteolytic activation of some viruses leads to its use as an antiviral drug for the prevention and treatment of acute respiratory virus infections. However, due to incompetent interpretation of several clinical trials followed by incredible controversy in the literature, the usage of APR was nearly stopped for a decade worldwide. In 2015-2020, after re-analysis of these clinical trials' data the restrictions in APR usage were lifted worldwide. This review discusses antiviral mechanisms of APR action and summarizes current knowledge and prospective regarding the use of APR treatment for diseases caused by RNA-containing viruses, including influenza and SARS-CoV-2 viruses, or as a part of combination antiviral treatment.

Multifactorial Traits of SARS-CoV-2 Cell Entry Related to Diverse Host Proteases and Proteins

The most effective way to control newly emerging infectious disease, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, is to strengthen preventative or therapeutic public health strategies before the infection spreads worldwide. However, global health systems remain at the early stages in anticipating effective therapeutics or vaccines to combat the SARS-CoV-2 pandemic. While maintaining social distance is the most crucial metric to avoid spreading the virus, symptomatic therapy given to patients on the clinical manifestations helps save lives. The molecular properties of SARS-CoV-2 infection have been quickly elucidated, paving the way to therapeutics, vaccine development, and other medical interventions. Despite this progress, the detailed biomolecular mechanism of SARS-CoV-2 infection remains elusive. Given virus invasion of cells is a determining factor for virulence, understanding the viral entry process can be a mainstay in controlling newly emerged viruses. Since viral entry is mediated by selective cellular proteases or proteins associated with receptors, identification and functional analysis of these proteins could provide a way to disrupt virus propagation. This review comprehensively discusses cellular machinery necessary for SARS-CoV-2 infection. Understanding multifactorial traits of the virus entry will provide a substantial guide to facilitate antiviral drug development.

Delineation of the healthy rabbit lung by immunohistochemistry - a technical note

Investigation and studies of pulmonary diseases and injuries require pre-clinical animal models. The rabbit lung model is widely used and allows for a diverse set of readouts. Among them, histology and immunohistochemistry are of invaluable merit because qualitative and quantitative information about tissue morphology and composition can be easily obtained. In this technical note, we performed several histological and immunohistochemical stainings in the rabbit healthy naïve lung tissue. Overnight formalin fixation with subsequent paraffin embedding was compared to cryopreservation with a subsequent 10-minute formalin fixation prior to staining. Antigen retrieval (AR) for paraffin embedded sections proved to enhance the corresponding signals compared to analogous staining without AR. Advantages and disadvantages of chromogenic versus immunofluorescence stainings were discussed. In addition, several morphological structures, such as the intrapulmonary bronchus with its mucosal folds, the pulmonary artery, the alveoli and the lymph nodes, were stained with various stainings at the same site in order to give a comprehensive picture of their composition. Besides Haematoxylin&Eosin and Elastica van Gieson staining, collagen I, collagen III, fibronectin, α-SMA, ki-67 and protease-activated receptor-2 (PAR-2) immunohistochemistry was performed. Collagen I, collagen III and fibronectin expression was positive at the outer rim of the pulmonary arteries, while the inner rim was collagen III positive. Moreover, the fibronectin staining in the intrapulmonary bronchus showed an opposite trend when compared to the collagen III staining. The alveoli exhibited PAR-2 expression, while PAR-2 was not expressed in lymph nodes of the healthy rabbit lung.