New therapeutic approaches against pulmonary fibrosis.

Pulmonary fibrosis is the end-stage change of a large class of lung diseases characterized by the proliferation of fibroblasts and the accumulation of a large amount of extracellular matrix, accompanied by inflammatory damage and tissue structure destruction, which also shows the normal alveolar tissue is damaged and then abnormally repaired resulting in structural abnormalities (scarring). Pulmonary fibrosis has a serious impact on the respiratory function of the human body, and the clinical manifestation is progressive dyspnea. The incidence of pulmonary fibrosis-related diseases is increasing year by year, and no curative drugs have appeared so far. Nevertheless, research on pulmonary fibrosis have also increased in recent years, but there are no breakthrough results. Pathological changes of pulmonary fibrosis appear in the lungs of patients with coronavirus disease 2019 (COVID-19) that have not yet ended, and whether to improve the condition of patients with COVID-19 by means of the anti-fibrosis therapy, which are the questions we need to address now. This review systematically sheds light on the current state of research on fibrosis from multiple perspectives, hoping to provide some references for design and optimization of subsequent drugs and the selection of anti-fibrosis treatment plans and strategies.

The mechanism of Qingwen Gupi decoction on pulmonary fibrosis based on metabolomics and intestinal flora.

AIMS: To evaluate the effects of the Qingwen Gupi decoction (QGT) in a rat model of bleomycin-induced pulmonary fibrosis (PF), and explore the underlying mechanisms by integrating UPLC-Q-TOF/MS metabolomics and 16S rDNA sequencing of gut microbiota. METHODS AND RESULTS: The animals were randomly divided into the control, PF model, pirfenidone-treated, and low-, medium-, and high-dose QGT groups. The lung tissues were examined and the expression of TGF-ß, SMAD-3, and SMAD-7 mRNAs in the lung tissues were analyzed. Metabolomic profiles were analyzed by UPLC-QTOF/MS, and the intestinal flora were examined by prokaryotic 16 rDNA sequencing. Pathological examination and biochemical indices revealed that QGT treatment improved the symptoms of PF by varying degrees. Furthermore, QGT significantly downregulated TGF-ß1 and Smad-3 mRNAs and increased the expression levels of Smad-7. QGT-L in particular increased the levels of 18 key metabolic biomarkers that were associated with nine gut microbial species and may exert antifibrosis effects through arachidonic acid metabolism, glycerophospholipid metabolism, and phenylalanine metabolism. CONCLUSIONS: QGT alleviated PF in a rat model through its anti-inflammatory, antioxidant, and anti-fibrotic effects, and by reversing bleomycin-induced gut dysbiosis.This study lays the foundation for further research on the pathological mechanisms of PF and the development of new drug candidates.

Therapeutic potency of compound RMY-205 for pulmonary fibrosis induced by SARS-CoV-2 nucleocapsid protein.

Pulmonary fibrosis is a typical sequela of coronavirus disease 2019 (COVID-19), which is linked with a poor prognosis for COVID-19 patients. However, the underlying mechanism of pulmonary fibrosis induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. Here, we demonstrated that the nucleocapsid (N) protein of SARS-CoV-2 induced pulmonary fibrosis by activating pulmonary fibroblasts. N protein interacted with the transforming growth factor ß receptor I (TßRI), to disrupt the interaction of TßRI-FK506 Binding Protein12 (FKBP12), which led to activation of TßRI to phosphorylate Smad3 and boost expression of pro-fibrotic genes and secretion of cytokines to promote pulmonary fibrosis. Furthermore, we identified a compound, RMY-205, that bound to Smad3 to disrupt TßRI-induced Smad3 activation. The therapeutic potential of RMY-205 was strengthened in mouse models of N protein-induced pulmonary fibrosis. This study highlights a signaling pathway of pulmonary fibrosis induced by N protein and demonstrates a novel therapeutic strategy for treating pulmonary fibrosis by a compound targeting Smad3.

Effects of Resveratrol on Pulmonary Fibrosis via TGF-ß/Smad/ERK Signaling Pathway.

Pulmonary fibrosis (PF) is a progressive pulmonary disease with no effective treatment and high mortality. Resveratrol has shown promising benefits in the treatment of PF. However, the probable efficacy and underlying mechanism of resveratrol in PF treatment remain unclear. This study investigates the intervention effects and potential mechanisms underpinning the treatment of PF with resveratrol. The histopathological analysis of lung tissues in PF rats showed that resveratrol improved collagen deposition and reduced inflammation. Resveratrol decreased the levels of collagen, glutathione, superoxide dismutase, myeloperoxidase, and hydroxyproline, lowered total anti-oxidant capacity, and suppressed the migration of TGF-[Formula: see text]1 and LPS-induced 3T6 fibroblasts. With resveratrol intervention, the protein and RNA expressions of TGF-[Formula: see text]1, a-SMA, Smad3/4, p-Smad3/4, CTGF, and p-ERK1/2 were markedly downregulated. Similarly, the protein and RNA expression levels of Col-1 and Col-3 were significantly downregulated. However, Smad7 and ERK1/2 were evidently upregulated. The protein and mRNA expression levels of TGF-[Formula: see text], Smad, and p-ERK correlated positively with the lung index, while the protein and mRNA expression levels of ERK correlated negatively with the lung index. These results reveal that resveratrol may have therapeutic effects on PF by reducing collagen deposition, oxidation, and inflammation. The mechanism is associated with the regulation of the TGF-[Formula: see text]/Smad/ERK signaling pathway.

The Effects of Statins on Respiratory Symptoms and Pulmonary Fibrosis in COVID-19 Patients with Diabetes Mellitus: A Longitudinal Multicenter Study.

The aim of this prospective cohort study was to explore the effect of statins on long-term respiratory symptoms and pulmonary fibrosis in coronavirus disease 2019 (COVID-19) patients with diabetes mellitus (DM). Patients were recruited from three tertiary hospitals, categorized into Statin or Non-statin groups, and assessed on days 0, 28, and 90 after symptoms onset to record the duration of symptoms. Pulmonary fibrosis was scored at baseline and follow-up time points by high-resolution computed tomography scans. Each group comprised 176 patients after propensity score matching. Data analysis revealed that the odds of having cough and dyspnea were significantly higher in the Non-statin group compared to the Statin group during the follow-up period. Overall, there was no significant difference in the change in pulmonary fibrosis score between groups. However, Non-statin patients with > 5 years of DM were more likely to exhibit a significantly higher fibrosis score during the follow-up period as compared to their peers in the Statin group. Our results suggest that the use of statins is associated with a lower risk of developing chronic cough and dyspnea in diabetic patients with COVID-19, and may reduce pulmonary fibrosis associated with COVID-19 in patients with long-term (> 5 years) DM.

Recent advances in ginsenosides against respiratory diseases: Therapeutic targets and potential mechanisms.

BACKGROUND: Respiratory diseases mainly include asthma, influenza, pneumonia, chronic obstructive pulmonary disease, pulmonary hypertension, lung fibrosis, and lung cancer. Given their high prevalence and poor prognosis, the prevention and treatment of respiratory diseases are increasingly essential. In particular, the development for the novel strategies of drug treatment has been a hot topic in the research field. Ginsenosides are the major component of Panax ginseng C. A. Meyer (ginseng), a food homology and well-known medicinal herb. In this review, we summarize the current therapeutic effects and molecular mechanisms of ginsenosides in respiratory diseases. METHODS: The reviewed studies were retrieved via a thorough analysis of numerous articles using electronic search tools including Sci-Finder, ScienceDirect, PubMed, and Web of Science. The following keywords were used for the online search: ginsenosides, asthma, influenza, pneumonia, chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH), lung fibrosis, lung cancer, and clinical trials. We summarized the findings and the conclusions from 176 manuscripts on ginsenosides, including research articles and reviews. RESULTS: Ginsenosides Rb1, Rg1, Rg3, Rh2, and CK, which are the most commonly reported ginsenosides for treating of respiratory diseases, and other ginsenosides such as Rh1, Rk1, Rg5, Rd and Re, all primarily reduce pneumonia, fibrosis, and inhibit tumor progression by targeting NF-κB, TGF-ß/Smad, PI3K/AKT/mTOR, and JNK pathways, thereby ameliorating respiratory diseases. CONCLUSION: This review provides novel ideas and important aspects for the future research of ginsenosides for treating respiratory diseases.

Role of vitamin D3 in selected pulmonary diseases with particular emphasis on lung fibrosis.

INTRODUCTION AND OBJECTIVE: For many years vitamin D3 was known only as a regulator of the calcium-phosphate and water-electrolyte balances. Recent studies have paid special attention to other biological effects of calcitriol (the bioactive form of vitamin D3) with particular emphasis on its influence on immune function. Thus, any alterations, especially deficiencies, in the physiological level of calcitriol have serious health consequences. The aim of the study was to summarise the current state of knowledge concerning the role of vitamin D3 in selected pulmonary diseases. REVIEW METHODS: The review was based on data obtained from articles published in PubMed between 2000-2022. Papers were reviewed for scientific merit and relevance. BRIEF DESCRIPTION OF THE STATE OF KNOWLEDGE: In the reviewed literature, much attention was paid to clinical studies focused on the role of vitamin D3 in the pathogenesis of selected respiratory diseases. As revealed in research over the last two decades, vitamin D3 deficiency increases the risk and worsens the course of asthma, cystic fibrosis, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, as well as COVID-19. Surprisingly, vitamin D supplementation has not always proved to be an effective therapeutic strategy. The review also presents the unique concept of the possibility of using vitamin D3 in the prevention and treatment of pulmonary fibrosis in the course of hypersensitivity pneumonitis. SUMMARY: Due to the multiplicity and variety of factors that affect the metabolism of vitamin D3, effective counteracting, and even more eliminating the negative consequences of disorders in the level and activity of calcitriol in the respiratory tract, seems to be a breakneck action. On the other hand, only a deep understanding of the role of calcitriol in the pathogenesis of lung diseases provides the chance to develop an effective therapy.

Ovatodiolide inhibits SARS-CoV-2 replication and ameliorates pulmonary fibrosis through suppression of the TGF-ß/TßRs signaling pathway.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection continues to pose threats to public health. The clinical manifestations of lung pathology in COVID-19 patients include sustained inflammation and pulmonary fibrosis. The macrocyclic diterpenoid ovatodiolide (OVA) has been reported to have anti-inflammatory, anti-cancer, anti-allergic, and analgesic activities. Here, we investigated the pharmacological mechanism of OVA in suppressing SARS-CoV-2 infection and pulmonary fibrosis in vitro and in vivo. Our results revealed that OVA was an effective SARS-CoV-2 3CLpro inhibitor and showed remarkable inhibitory activity against SARS-CoV-2 infection. On the other hand, OVA ameliorated pulmonary fibrosis in bleomycin (BLM)-induced mice, reducing inflammatory cell infiltration and collagen deposition in the lung. OVA decreased the levels of pulmonary hydroxyproline and myeloperoxidase, as well as lung and serum TNF-ɑ, IL-1ß, IL-6, and TGF-ß in BLM-induced pulmonary fibrotic mice. Meanwhile, OVA reduced the migration and fibroblast-to-myofibroblast conversion of TGF-ß1-induced fibrotic human lung fibroblasts. Consistently, OVA downregulated TGF-ß/TßRs signaling. In computational analysis, OVA resembles the chemical structures of the kinase inhibitors TßRI and TßRII and was shown to interact with the key pharmacophores and putative ATP-binding domains of TßRI and TßRII, showing the potential of OVA as an inhibitor of TßRI and TßRII kinase. In conclusion, the dual function of OVA highlights its potential for not only fighting SARS-CoV-2 infection but also managing injury-induced pulmonary fibrosis.

Qimai Feiluoping decoction inhibits mitochondrial complex I-mediated oxidative stress to ameliorate bleomycin-induced pulmonary fibrosis.

BACKGROUND: Qimai Feiluoping decoction (QM), a Traditional Chinese Medicine formula, has been included in rehabilitation program for functional disorders of discharged COVID-19 patients. QM has been proved to effectively improve the clinical symptoms and imaging signs of PF in COVID-19 convalescent patients. PURPOSE: This study to explore the pharmacological effect of QM against PF from the perspectives of imaging, pathological staining, and molecular mechanisms, and identify possible active components. METHODS: Micro-CT imaging and immunohistochemical staining were investigated to verify the therapeutic effect of QM in the bleomycin (BLM)-induced PF mouse model. The 4D-label-free proteomics analysis of lung tissues was then conducted to explore the novel mechanisms of QM against PF, which were further validated by a series of experiments. The possible components of QM in plasma and lung tissues were identified with UHPLC/IM-QTOF-MS analysis. RESULTS: The results from micro-CT imaging and pathological staining revealed that QM treatment can inhibit BLM-induced lung injury, extracellular matrix accumulation and TGF-ß expression in the mouse model with PF. The 4D-label-free proteomics analysis demonstrated that the partial subunit proteins of mitochondrial complex I and complex II might be potential targets of QM against PF. Furthermore, QM treatment can inhibit BLM-induced mitochondrial ROS content to promote ATP production and decrease oxidative stress injury in the mouse and cell models of PF, which was mediated by the inhibition of mitochondrial complex I. Finally, a total of 13 protype compounds and 15 metabolites from QM in plasma and lung tissues were identified by UHPLC/IM-QTOF-MS, and liquiritin and isoliquiritigenin from Glycyrrhizae radix et rhizoma could be possible active compounds against PF. CONCLUSION: It concludes that QM treatment could treat PF by inhibiting mitochondrial complex I-mediated mitochondrial oxidated stress injury, which could offer new insights into the pharmacological mechanisms of QM in the clinical application of PF patients.

Inositol Alleviates Pulmonary Fibrosis by Promoting Autophagy via Inhibiting the HIF-1α-SLUG Axis in Acute Respiratory Distress Syndrome.

The effective remission of acute respiratory distress syndrome- (ARDS-) caused pulmonary fibrosis determines the recovery of lung function. Inositol can relieve lung injuries induced by ARDS. However, the mechanism of myo-inositol in the development of ARDS is unclear, which limits its use in the clinic. We explored the role and mechanism of myo-inositol in the development of ARDS by using an in vitro lipopolysaccharide- (LPS-) established alveolar epithelial cell inflammation model and an in vivo ARDS mouse model. Our results showed that inositol can alleviate the progression of pulmonary fibrosis. More significantly, we found that inositol can induce autophagy to inhibit the progression pulmonary fibrosis caused by ARDS. In order to explore the core regulators of ARDS affected by inositol, mRNA-seq sequencing was performed. Those results showed that transcription factor HIF-1α can regulate the expression of SLUG, which in turn can regulate the key gene E-Cadherin involved in cell epithelial-mesenchymal transition (EMT) as well as N-cadherin expression, and both were regulated by inositol. Our results suggest that inositol activates autophagy to inhibit EMT progression induced by the HIF-1α/SLUG signaling pathway in ARDS, and thereby alleviates pulmonary fibrosis.

Amelioration of Lung Fibrosis by Total Flavonoids of Astragalus via Inflammatory Modulation and Epithelium Regeneration.

Idiopathic Pulmonary Fibrosis (IPF) is identifiable by the excessive increase of mesenchyme paired with the loss of epithelium. Total flavonoids of Astragalus (TFA), the main biologically active ingredient of the traditional Chinese medicine, Astragalus membranaceus (Huangqi), shows outstanding effects on treating pulmonary disorders, including COVID-19-associated pulmonary dysfunctions. This study was designed to evaluate the efficacy of TFA on treating pulmonary fibrosis and the possible mechanisms behind these effects. A549 cells were treated with TGF-[Formula: see text]1 and TFA to observe the potential effects of TFA on regulating alveolar epithelial cell proliferation, TGF-[Formula: see text]1-induced EMT, and the underlying mechanisms in vitro. Then, mouse pulmonary fibrosis was induced with a single intra-tracheal injection of bleomycin, and TFA was administrated by i.p. injection. Lung fibrosis was evaluated through histological and molecular analyses, and the possible mechanisms were explored using immunological methods. The results demonstrated that TFA could promote cell proliferation but inhibit TGF-[Formula: see text]1-induced EMT on A549 cells. TFA attenuated BLM-induced pulmonary fibrosis in mice by modulating inflammatory infiltration and M2 macrophage polarization; it furthermore modulated EMT through regulating the TGF-[Formula: see text]1/Smad pathway. In addition, TFA augmented the expression of the Wnt7b protein, which plays an important role in alveolar epithelium reparation. In conclusion, TFA alleviated bleomycin-induced mouse lung fibrosis by preventing the fibrotic response and increasing epithelium regeneration.

Cepharanthine Ameliorates Pulmonary Fibrosis by Inhibiting the NF-κB/NLRP3 Pathway, Fibroblast-to-Myofibroblast Transition and Inflammation.

Pulmonary fibrosis (PF) is one of the sequelae of Corona Virus Disease 2019 (COVID-19), and currently, lung transplantation is the only viable treatment option. Hence, other effective treatments are urgently required. We investigated the therapeutic effects of an approved botanical drug, cepharanthine (CEP), in a cell culture model of transforming growth factor-ß1 (TGF-ß1) and bleomycin (BLM)-induced pulmonary fibrosis rat models both in vitro and in vivo. In this study, CEP and pirfenidone (PFD) suppressed BLM-induced lung tissue inflammation, proliferation of blue collagen fibers, and damage to lung structures in vivo. Furthermore, we also found increased collagen deposition marked by α-smooth muscle actin (α-SMA) and Collagen Type I Alpha 1 (COL1A1), which was significantly alleviated by the addition of PFD and CEP. Moreover, we elucidated the underlying mechanism of CEP against PF in vitro. Various assays confirmed that CEP reduced the viability and migration and promoted apoptosis of myofibroblasts. The expression levels of myofibroblast markers, including COL1A1, vimentin, α-SMA, and Matrix Metallopeptidase 2 (MMP2), were also suppressed by CEP. Simultaneously, CEP significantly suppressed the elevated Phospho-NF-κB p65 (p-p65)/NF-κB p65 (p65) ratio, NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels, and elevated inhibitor of NF-κB Alpha (IκBα) degradation and reversed the progression of PF. Hence, our study demonstrated that CEP prevented myofibroblast activation and treated BLM-induced pulmonary fibrosis in a dose-dependent manner by regulating nuclear factor kappa-B (NF-κB)/ NLRP3 signaling, thereby suggesting that CEP has potential clinical application in pulmonary fibrosis in the future.

Thymol protects against bleomycin-induced pulmonary fibrosis via abrogation of oxidative stress, inflammation, and modulation of miR-29a/TGF-ß and PI3K/Akt signaling in mice.

Idiopathic pulmonary fibrosis is a terminal lung ailment that shares several pathological and genetic mechanisms with severe COVID-19. Thymol (THY) is a dietary compound found in thyme species that showed therapeutic effects against various diseases. However, the effect of THY against bleomycin (BLM)-induced lung fibrosis was not previously investigated. The current study investigated the ability of THY to modulate oxidative stress, inflammation, miR-29a/TGF-ß expression, and PI3K/phospho-Akt signaling in lung fibrosis. Mice were divided into Normal, THY (100 mg/kg, p.o.), BLM (15 mg/kg, i.p.), BLM + THY (50 mg/kg, p.o.), and BLM + THY (100 mg/kg, p.o.) groups and treated for four weeks. The obtained results showed that BLM + THY (50 mg/kg) and BLM + THY (100 mg/kg) reduced fibrotic markers; α-SMA and fibronectin, inflammatory mediators; TNF-α, IL-1ß, IL-6, and NF-kB and oxidative stress biomarkers; MDA, GSH, and SOD, relative to BLM group. Lung histopathological examination by H&E and Masson's trichrome stains confirmed the obtained results. Remarkably, expression levels of TGF-ß, PI3K, and phospho-Akt were decreased while miR-29a expression was elevated. In conclusion, THY effectively prevented BLM-induced pulmonary fibrosis by exerting significant anti-oxidant and anti-inflammatory effects. Our novel findings that THY upregulated lung miR-29a expression while decreased TGF-ß and PI3K/Akt signaling are worthy of further investigation as a possible molecular mechanism for THY's anti-fibrotic actions.

Shared mechanisms and crosstalk of COVID-19 and osteoporosis via vitamin D.

Recently accumulated evidence implicates a close association of vitamin D (VitD) insufficiency to the incidence and clinical manifestations of the COVID-19 caused by severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). Populations with insufficient VitD including patients with osteoporosis are more susceptible to SARS-COV-2 infection and patients with COVID-19 worsened or developed osteoporosis. It is currently unknown, however, whether osteoporosis and COVID-19 are linked by VitD insufficiency. In this study, 42 common targets for VitD on both COVID-19 and osteoporosis were identified among a total of 243 VitD targets. Further bioinformatic analysis revealed 8 core targets (EGFR, AR, ESR1, MAPK8, MDM2, EZH2, ERBB2 and MAPT) in the VitD-COVID-19-osteoporosis network. These targets are involved in the ErbB and MAPK signaling pathways critical for lung fibrosis, bone structural integrity, and cytokines through a crosstalk between COVID-19 and osteoporosis via the VitD-mediated conventional immune and osteoimmune mechanisms. Molecular docking confirmed that VitD binds tightly to the predicted targets. These findings support that VitD may target common signaling pathways in the integrated network of lung fibrosis and bone structural integrity as well as the immune systems. Therefore, VitD may serve as a preventive and therapeutic agent for both COVID-19 and osteoporosis.

When and how important is anti-fibrotic therapy in the post-COVID-19 period?

PURPOSE: In addition to the highly variable clinical presentation of acute COVID-19 infection, it can also cause various post-acute signs and symptoms. In our study, we aimed to examine the efficacy of anti-fibrotic therapy in patients who developed pulmonary fibrosis after COVID-19. METHODS: In total, 15 patients who applied to the Post-Covid Outpatient Clinic between May 2021 and August 2021 and were diagnosed with COVID-19 pneumonia, and whose cough, dyspnea, exertional dyspnea and low saturation continued to be present at least 12 weeks after the diagnosis, were included in the study. Off-label pirfenidone treatment was started according to the radiological findings, pulmonary function test parameters (PFT) and 6-minute walking test (6MWT) results. The patients were followed up for 12 weeks. RESULTS: While all of the FVC, FVC%, FEV1, FEV1%, DLCO%, DLCO/VA%, 6MWT, and room air saturation levels were observed to increase statistically significantly in the patients at the 12th week, it was determined that there was a statistically significant decrease in the pulse level in room air (p = 0.01, 0.01, 0.01, 0.01, 0.004, 0.001, 0.002, 0.001, and 0.002, respectively). In regression analysis based on radiological scoring, it was observed that the DLCO and room air saturation levels at the 12th week of the treatment were statistically significantly higher in patients with lower scores at the beginning (p = 0.04, 0.03). In addition, it was observed that anti-fibrotic treatment, which was started in the earliest period, i.e., 12 weeks after the diagnosis, resulted in an improvement in radiological, PFT and 6MWT parameters. CONCLUSION: Patients who still had dyspnea and low saturation 12 weeks after the diagnosis, defined as chronic COVID-19, should be evaluated for anti-fibrotic therapy after the necessary radiological and PFT evaluation. Early treatment commencement brings about, besides radiological improvement, a better response obtained in PFT and 6MWT (Tab. 2, Fig. 2, Ref. 21).

Human MIKO-1, a Hybrid Protein That Regulates Macrophage Function, Suppresses Lung Fibrosis in a Mouse Model of Bleomycin-Induced Interstitial Lung Disease.

Although interstitial lung disease (ILD) is a life-threatening pathological condition that causes respiratory failure, the efficiency of current therapies is limited. This study aimed to investigate the effects of human MIKO-1 (hMIKO-1), a hybrid protein that suppresses the abnormal activation of macrophages, on murine macrophage function and its therapeutic effect in a mouse model of bleomycin-induced ILD (BLM-ILD). To this end, the phenotype of thioglycolate-induced murine peritoneal macrophages co-cultured with hMIKO-1 was examined. The mice were assigned to normal, BLM-alone, or BLM + hMIKO-1 groups, and hMIKO-1 (0.1 mg/mouse) was administered intraperitoneally from day 0 to 14. The mice were sacrificed on day 28, and their lungs were evaluated by histological examination, collagen content, and gene expression levels. hMIKO-1 suppressed the polarization of murine macrophages to M2 predominance in vitro. The fibrosis score of lung pathology and lung collagen content of the BLM + hMIKO-1 group were significantly lower than those in the BLM-alone group. The expression levels of TNF-α, IL-6, IL-1ß, F4/80, and TIMP-1 in the lungs of the BLM + hMIKO-1 group were significantly lower than those in the BLM-alone group. These findings indicate that hMIKO-1 reduces lung fibrosis and may be a future therapeutic candidate for ILD treatment.

CFD simulation of porous microsphere particles in the airways of pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: Pulmonary fibrosis (PF) is a chronic progressive disease with an extremely high mortality rate and is a complication of COVID-19. Inhalable microspheres have been increasingly used in the treatment of lung diseases such as PF in recent years. Compared to the direct inhalation of drugs, a larger particle size is required to ensure the sustained release of microspheres. However, the clinical symptoms of PF may lead to the easier deposition of microspheres in the upper respiratory tract. Therefore, it is necessary to understand the effects of PF on the deposition of microspheres in the respiratory tract. METHODS: In this study, airway models with different degrees of PF in humans and mice were established, and the transport and deposition of microspheres in the airway were simulated using computational fluid dynamics. RESULTS: The simulation results showed that PF increases microsphere deposition in the upper respiratory tract and decreases bronchial deposition in both humans and mice. Porous microspheres with low density can ensure deposition in the lower respiratory tract and larger particle size. In healthy and PF humans, porous microspheres of 10 µm with densities of 700 and 400 kg/m³ were deposited most in the bronchi. Unlike in humans, microspheres larger than 4 µm are completely deposited in the upper respiratory tract of mice owing to their high inhalation velocity. For healthy and PF mice, microspheres of 6 µm with densities of and 100 kg/m³ are recommended. CONCLUSIONS: The results showed that with the exacerbation of PF, it is more difficult for microsphere particles to deposit in the subsequent airway. In addition, there were significant differences in the deposition patterns among the different species. Therefore, it is necessary to process specific microspheres from different individuals. Our study can guide the processing of microspheres and achieve differentiated drug delivery in different subjects to maximize therapeutic effects.

Pathophysiology of Pulmonary Fibrosis in the Context of COVID-19 and Implications for Treatment: A Narrative Review.

Pulmonary fibrosis (PF) is a feared outcome of many pulmonary diseases which results in a reduction in lung compliance and capacity. The development of PF is relatively rare, but it can occur secondary to viral pneumonia, especially COVID-19 infection. While COVID-19 infection and its complications are still under investigation, we can look at a similar outbreak in the past to gain better insight as to the expected long-term outcomes of COVID-19 patient lung function. In the current article, we review the literature relative to PF via PubMed. We also performed a literature search for COVID-related pathological changes in the lungs. Finally, the paper was reviewed and summarized based on the studies' integrity, relative, or power calculations. This article provides a narrative review that endeavors to elucidate the current understanding of the pathophysiological mechanisms underlying PF and therapeutic strategies. We also discussed the potential for preventing progression to the fibrotic state within the context of the COVID-19 pandemic. With the massive scale of the COVID-19 pandemic, we expect there should more instances of PF due to COVID-19 infection. Patients who survive severe COVID-19 infection may suffer from a high incidence of PF.

N-acetylcysteine as a therapeutic approach to post-COVID-19 pulmonary fibrosis adjunctive treatment.

OBJECTIVE: Growing interest is directed to the outcomes of COVID-19 in survivors, both in the convalescent period and in the long-term, which are responsible for morbidity and quality of life deterioration. This article aims to describe the mechanisms supporting the possible use of NAC as an adjuvant treatment for post-COVID-19 pulmonary fibrosis. MATERIALS AND METHODS: A search was performed in PubMed/MEDLINE. RESULTS: Interstitial changes have been observed in the CT scan of COVID-19 pneumonia. In patients with respiratory outcomes in the post-COVID-19 stage, glutathione (GSH) deficiency was found and interpreted as a reaction to the inflammatory cascade caused by the viral infection, while the pathophysiological process of pulmonary fibrosis involves numerous cytokines, such as TGF-ß, TNF-α, IL-1, PDGF and VEGF. NAC has a good tolerability profile, is easily administered orally and inexpensively, and has antioxidant and anti-inflammatory effects that may target the pathophysiologic mechanisms involved in pulmonary fibrosis. It may revert GSH deficiency, exerts direct and indirect antioxidant activity, anti-inflammatory activity and improves immune T-cell response. CONCLUSIONS: The mechanism of action of NAC suggests a role in the treatment of pulmonary fibrosis induced by COVID-19.

Pirfenidone ameliorates early pulmonary fibrosis in LPS-induced acute respiratory distress syndrome by inhibiting endothelial-to-mesenchymal transition via the Hedgehog signaling pathway.

Pulmonary vascular endothelial dysfunction is a key pathogenic mechanism in acute respiratory distress syndrome (ARDS), resulting in fibrosis in lung tissues, including in the context of COVID-19. Pirfenidone (PFD) has become a novel therapeutic agent for treating idiopathic pulmonary fibrosis (IPF) and can improve lung function, inhibit fibrosis and inhibit inflammation. Recently, endothelial-to-mesenchymal transition (EndMT) was shown to play a crucial role in various respiratory diseases. However, the role of PFD in the course of EndMT in LPS-induced ARDS remains poorly understood. The purpose of this study was to explore the anti-EndMT effects of PFD on pulmonary fibrosis after LPS-induced ARDS. First, we determined that PFD significantly reduced LPS-induced ARDS, as shown by significant pathological alterations, and alleviated the oxidative stress and inflammatory response in vitro and in vivo. Furthermore, PFD decreased pulmonary fibrosis in LPS-induced ARDS by inhibiting EndMT and reduced the expression levels of Hedgehog (HH) pathway target genes, such as Gli1 and α-SMA, after LPS induction. In summary, this study confirmed that inhibiting the HH pathway by PFD could decrease pulmonary fibrosis by downregulating EndMT in LPS-induced ARDS. In conclusion, we demonstrate that PFD is a promising agent to attenuate pulmonary fibrosis following ARDS in the future.