COVID-19 and the lung: from interstitial pneumonia to pulmonary fibrosis

The novel coronavirus-induced disease led to a pandemic that poses a global threat to human health. The most common cause of hospitalisation for COVID-19 is interstitial pneumonia that may be complicated by Acute Respiratory Distress Syndrome (ARDS). The monitoring of patients who have recovered from COVID-associated pneumonia demonstrates that the significant reduction in diffuse lung capacity and associated fibrotic signs in the lung parenchyma are factors associated with a negative prognosis. Thus, the long-term consequences of COVID-19 appear crucial. Risk factors, histopathological characterization, prevalence, and management of post-COVID-19 pulmonary fibrosis are poorly understood. This review addresses underlying pathobiological mechanisms and the possible predictors which might lead to the development of fibrotic lung remodeling. Potential therapeutic modalities include anti-fibrotic drugs, prolonged use of corticosteroids, other anti-inflammatory and immunosuppressive drugs, spironolactone, azithromycine, with further multiple novel compounds under investigation. Copyright © 2022, SOLEN s.r.o.. All rights reserved.

Endogenous reparative pluripotent Muse cells with a unique immune privilege system: Hint at a new strategy for controlling acute and chronic inflammation.

Multilineage-differentiating stress enduring (Muse) cells, non-tumorigenic endogenous pluripotent stem cells, reside in the bone marrow (BM), peripheral blood, and connective tissue as pluripotent surface marker SSEA-3(+) cells. They express other pluripotent markers, including Nanog, Oct3/4, and Sox2 at moderate levels, differentiate into triploblastic lineages, self-renew at a single cell level, and exhibit anti-inflammatory effects. Cultured mesenchymal stromal cells (MSCs) and fibroblasts contain several percent of SSEA-3(+)-Muse cells. Circulating Muse cells, either endogenous or administered exogenously, selectively accumulate at the damaged site by sensing sphingosine-1-phosphate (S1P), a key mediator of inflammation, produced by damaged cells and replace apoptotic and damaged cells by spontaneously differentiating into multiple cells types that comprise the tissue and repair the tissue. Thus, intravenous injection is the main route for Muse cell treatment, and surgical operation is not necessary. Furthermore, gene introduction or cytokine induction are not required for generating pluripotent or differentiated states prior to treatment. Notably, allogenic and xenogenic Muse cells escape host immune rejection after intravenous injection and survive in the tissue as functioning cells over 6 and ∼2 months, respectively, without immunosuppressant treatment. Since Muse cells survive in the host tissue for extended periods of time, therefore their anti-inflammatory, anti-fibrotic, and trophic effects are long-lasting. These unique characteristics have led to the administration of Muse cells via intravenous drip in clinical trials for stroke, acute myocardial infarction, epidermolysis bullosa, spinal cord injury, neonatal hypoxic ischemic encephalopathy, amyotrophic lateral sclerosis, and COVID-19 acute respiratory distress syndrome without HLA-matching or immunosuppressive treatment.

Pirfenidone and post-Covid-19 pulmonary fibrosis: invoked again for realistic goals.

Pirfenidone (PFN) is an anti-fibrotic drug with significant anti-inflammatory property used for treatment of fibrotic conditions such as idiopathic pulmonary fibrosis (IPF). In the coronavirus disease 2019 (Covid-19) era, severe acute respiratory syndrome 2 (SARS-CoV-2) could initially lead to acute lung injury (ALI) and in severe cases may cause acute respiratory distress syndrome (ARDS) which is usually resolved with normal lung function. However, some cases of ALI and ARDS are progressed to the more severe critical stage of pulmonary fibrosis commonly named post-Covid-19 pulmonary fibrosis which needs an urgent address and proper management. Therefore, the objective of the present study was to highlight the potential role of PFN in the management of post-Covid-19 pulmonary fibrosis. The precise mechanism of post-Covid-19 pulmonary fibrosis is related to the activation of transforming growth factor beta (TGF-ß1), which activates the release of extracellular proteins, fibroblast proliferation, fibroblast migration and myofibroblast conversion. PFN inhibits accumulation and recruitment of inflammatory cells, fibroblast proliferation, deposition of extracellular matrix in response to TGFß1 and other pro-inflammatory cytokines. In addition, PFN suppresses furin (TGFß1 convertase activator) a protein effector involved in the entry of SARS-CoV-2 and activation of TGFß1, and thus PFN reduces the pathogenesis of SARS-CoV-2. Besides, PFN modulates signaling pathways such as Wingless/Int (Wnt/ß-catenin), Yes-Associated Protein (YAP)/Transcription Co-Activator PDZ Binding Motif (TAZ) and Hippo Signaling Pathways that are involved in the pathogenesis of post-Covid-19 pulmonary fibrosis. In conclusion, the anti-inflammatory and anti-fibrotic properties of PFN may attenuate post-Covid-19 pulmonary fibrosis.

Anti-fibrotic agents could be the game-changer for post-COVID-19 pulmonary fibrosis treatment

More than 220 countries and territories are globally affected by the recent pandemic COVID-19 which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There is possibility of third wave of this pandemic as per epidemiological and public health experts. Besides that post-COVID-19 complications are alarming matter to look upon. Post-COVID-19 complications include several symptoms like as persistent fever;cough;fatigue;headache;attention disorder;dyspnea;anosmia;ageusia;chest pain discomfort;various respiratory illness;acute respiratory distress syndrome (ARDS) etc., and here the things to worry about is the development of pulmonary fibrosis after COVID-19. In some COVID-19 patients, hyperinflammation in the form of 'cytokine storm' along with dysregulated immune response, alveolar epithelial tissue injury and wound repair collectively cause this secondary pulmonary fibrosis. Therefore, using antifibrotic agents e.g. pirfenidone, nintedanib and other natural compounds could be meaningful in these circumstances although their efficacy in treating COVID-19 is subject to more detailed laboratory research works. In this review article, we have discussed the progression of pulmonary fibrosis development which is triggered by COVID-19;probable solutions with anti-fibrotic agents including anti-fibrotic drugs, some wellknown natural compounds, combined anti-fibrotic therapies;and the current challenges of this field. [ FROM AUTHOR] Copyright of European Journal of Biological Research is the property of Journal of Biology & Earth Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Drug Targeting and Nanomedicine: Lessons Learned from Liver Targeting and Opportunities for Drug Innovation.

Drug targeting and nanomedicine are different strategies for improving the delivery of drugs to their target. Several antibodies, immuno-drug conjugates and nanomedicines are already approved and used in clinics, demonstrating the potential of such approaches, including the recent examples of the DNA- and RNA-based vaccines against COVID-19 infections. Nevertheless, targeting remains a major challenge in drug delivery and different aspects of how these objects are processed at organism and cell level still remain unclear, hampering the further development of efficient targeted drugs. In this review, we compare properties and advantages of smaller targeted drug constructs on the one hand, and larger nanomedicines carrying higher drug payload on the other hand. With examples from ongoing research in our Department and experiences from drug delivery to liver fibrosis, we illustrate opportunities in drug targeting and nanomedicine and current challenges that the field needs to address in order to further improve their success.

Virus infection induced pulmonary fibrosis.

Pulmonary fibrosis is the end stage of a broad range of heterogeneous interstitial lung diseases and more than 200 factors contribute to it. In recent years, the relationship between virus infection and pulmonary fibrosis is getting more and more attention, especially after the outbreak of SARS-CoV-2 in 2019, however, the mechanisms underlying the virus-induced pulmonary fibrosis are not fully understood. Here, we review the relationship between pulmonary fibrosis and several viruses such as Human T-cell leukemia virus (HTLV), Human immunodeficiency virus (HIV), Cytomegalovirus (CMV), Epstein-Barr virus (EBV), Murine γ-herpesvirus 68 (MHV-68), Influenza virus, Avian influenza virus, Middle East Respiratory Syndrome (MERS)-CoV, Severe acute respiratory syndrome (SARS)-CoV and SARS-CoV-2 as well as the mechanisms underlying the virus infection induced pulmonary fibrosis. This may shed new light on the potential targets for anti-fibrotic therapy to treat pulmonary fibrosis induced by viruses including SARS-CoV-2.