Amelioration of bleomycin-induced pulmonary fibrosis in a mouse model by a combination therapy of bosentan and imatinib

Unilateral Bleomycin-induced Interstitial Pneumonitis Mouse Model With Both a Healthy and a Diseased Lung

BACKGROUND/AIM

A standard mouse model of pulmonary fibrosis has been created by intratracheal or intraperitoneal administration of bleomycin. However, a difficulty presented by this traditional method is its high mortality rate of more than 50% after bleomycin administration. In this study, we aimed to establish a unilateral lung disease model and to assess its feasibility and usefulness.

MATERIALS AND METHODS

After 6-week-old C57BL/6 mice were anesthetized, a 1.7Fr microcatheter was advanced into the trachea using an otoscope. Then, 1.0 mg/kg of bleomycin was injected into bilateral lung at the trachea (n=13) or unilateral lung (n=14) after advancing the microcatheter to the left main bronchus under fluoroscopy. Body weight change and survival of bilateral and unilateral lung disease group mice at day 28 were compared using Mann-Whitney and log-rank tests. Lungs were extracted and evaluated using Masson trichrome staining.

RESULTS

Body weights decreased 75.7%±14.0% in the bilateral lung disease group, but were greater, 94.1%±11.4%, in the unilateral lung disease group (p=0.03). Overall survival rates at day 28 were 30.8% and 85.7% in the bilateral and unilateral lung disease groups, respectively. Survival was significantly better in the unilateral lung disease model (p=0.01). Histological evaluation confirmed collagen deposition only in the bleomycin injected lung in the unilateral lung disease model.

CONCLUSION

Establishing both a healthy and a diseased lung in the same individual model was feasible, achieving lessened body weight loss and more favorable survival. This technique allows for a more efficacious research design, where both the efficacy and adverse effects of a pharmaceutical agent can be evaluated in a single animal.

Efficacy of umbelliferone-loaded nanostructured lipid carrier in the management of bleomycin-induced idiopathic pulmonary fibrosis: experimental and network pharmacology insight

Idiopathic pulmonary fibrosis (IPF) is a severe and progressive lung disorder with an average survival rate of 3 to 5 years. IPF presents a significant challenge in clinical management, necessitating novel therapeutic approaches. Nanostructured lipid carriers (NLCs) have proven to be promising vehicles for targeted drug delivery to the lung tissues. This research focuses on formulating and evaluating umbelliferone (UMB)-loaded NLCs for the treatment of IPF. UMB-NLC was formulated using the hot emulsion ultrasonication method and was characterized. The formulation was then tested for its efficacy in a bleomycin-induced IPF mice model. Leukocyte infiltration and interleukin-6 were estimated in the bronchoalveolar lavage fluid (BALF). Various antioxidant activities were also assessed for the formulation, followed by histopathological analysis. Furthermore, an in silico mechanistic approach using network pharmacology was carried out to obtain genes of interest. Particle size analysis revealed a mean size of 174.9 ± 3.66 nm for UMB-NLC, ideal for lung tissue targeting. Zeta potential measurements indicated good stability (-34.3 ± 1.35 mV) for long-term storage. Fourier transform infrared spectroscopy (FTIR) confirmed the successful encapsulation of UMB within the lipid matrix of NLCs. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) demonstrated the amorphous state of UMB-NLC, indicating enhanced solubility and bioavailability. Field emission scanning electron microscopy (FESEM) revealed uniform, spherical particles in the nanometer range. Drug entrapment efficiency (EE%) and loading capacity (DL%) were found to be 85.03 ± 2.36% and 17.01 ± 0.48%, respectively, indicating efficient drug incorporation. In vitro release study showed uniform sustained drug release over 48 h, indicating the potential for prolonged therapeutic effect. In vivo studies using UMB-NLC demonstrated significant improvements in bleomycin-induced IPF. A restoration in body weight and lung/body-weight (L/B) ratio was observed compared to disease controls. BALF analysis revealed reduced leukocyte infiltration and decreased inflammatory cytokine IL-6 levels (**p < 0.01). Biochemical assays showed enhanced antioxidant status and reduced oxidative stress in lung tissues. Hydroxyproline content (HPO, **p < 0.01), malondialdehyde (MDA, ***p < 0.001), and total protein content (**p < 0.01) were significantly reduced, while glutathione (GSH, ***p < 0.001), superoxide dismutase (SOD, **p < 0.01), and catalase (CAT, **p < 0.01) were elevated. Histopathological analysis confirmed the attenuation of lung fibrosis with maintained alveolar architecture and reduced fibrotic deposition. Furthermore, network pharmacology identified UMB targets and IPF-related genes with a Venn diagram, and cytoHubba analysis revealed key hub genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment demonstrated UMB's involvement in IPF-related pathways, highlighting its therapeutic potential. Therefore, UMB-NLC may exhibit promising therapeutic potential in the treatment of IPF, offering targeted drug delivery, enhanced bioavailability, and improved efficacy in alleviating pulmonary inflammation and fibrosis.

Flavonoids for treating pulmonary fibrosis: Present status and future prospects

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with an unknown underlying cause. There is no complete cure for IPF; however, two anti-fibrotic agents (Nintedanib and pirfenidone) are approved by the USFDA to extend the patient's life span. Therefore, alternative therapies supporting the survival of fibrotic patients have been studied in recent literature. The abundance of phenolic compounds, particularly flavonoids, has gathered attention due to their potential health benefits. Various flavonoids, like naringin, quercetin, baicalin, baicalein, puerarin, silymarin, and kaempferol, exhibit anti-inflammatory and anti-oxidant properties, which help decrease lung fibrosis. Various databases, including PubMed, EBSCO, ProQuest, and Scopus, as well as particular websites, such as the World Health Organisation and the National Institutes of Health, were used to conduct a literature search. Several mechanisms of action of flavonoids are reported with the help of in vivo and cell line studies emphasizing their ability to modulate oxidative stress, inflammation, and fibrotic processes in the lungs. They are reported for the restoration of biomarkers like hydroxyproline, cytokines, superoxide dismutase, malondialdehyde and others associated with IPF and for modulating various pathways responsible for the progression of pulmonary fibrosis. Yet, flavonoids have some drawbacks, such as poor solubility, challenging drug loading, stability issues, and scarce bioavailability. Therefore, novel formulations of flavonoids are explored, including liposomes, solid lipid microparticles, polymeric nanoparticles, nanogels, and nanocrystals, to enhance the therapeutic efficacy of flavonoids in pulmonary fibrosis. This review focuses on the role of flavonoids in mitigating idiopathic pulmonary fibrosis, their mode of action and novel formulations.

Endothelial cell-derived MMP19 promotes pulmonary fibrosis by inducing E(nd)MT and monocyte infiltration

BACKGROUND

Matrix metalloproteinases (MMPs) play important roles in remodeling the extracellular matrix and in the pathogenesis of idiopathic pulmonary fibrosis (IPF). MMP19, which is an MMP, was significantly upregulated in hyperplastic alveolar epithelial cells in IPF lung tissues and promoted epithelial-mesenchymal transition (EMT). Recent studies have demonstrated that endothelial-to-mesenchymal transition (E(nd)MT) contributes to pulmonary fibrosis. However, the role of MMP19 in pulmonary vascular injury and repair and E(nd)MT remains unclear.

METHODS

To determine the role of MMP19 in E(nd)MT and pulmonary fibrosis. MMP19 expressions were determined in the lung endothelial cells of IPF patients and bleomycin (BLM)-induced mice. The roles of MMP19 in E(nd)MT and endothelial barrier permeability were studied in the MMP19 cDNA-transfected primary human pulmonary microvascular endothelial cells (HPMECs) and MMP19 adenoassociated virus (MMP19-AAV)-infected mice. The regulatory mechanism of MMP19 in pulmonary fibrosis was elucidated by blocking its interacting proteins SDF1 and ET1 with AMD3100 and Bosentan, respectively.

RESULTS

In this study, we found that MMP19 expression was significantly increased in the lung endothelial cells of IPF patients and BLM-induced mice compared to the control groups. MMP19 promoted E(nd)MT and the migration and permeability of HPMECs in vitro, stimulated monocyte infiltration into the alveolus, and aggravated BLM-induced pulmonary fibrosis in vivo. SDF1 and Endothelin-1 (ET1) were physically associated with MMP19 in HPMECs and colocalized with MMP19 in endothelial cells in IPF patient lung tissues. AMD3100 and bosentan alleviated the fibrosis induced by MMP19 in the BLM mouse model.

CONCLUSION

MMP19 promoted E(nd)MT by interacting with ET1 and stimulated monocyte infiltration into lung tissues via the SDF1/CXCR4 axis, thus aggravating BLM-induced pulmonary fibrosis. Vascular integrity regulated by MMP19 could be a promising therapeutic target for suppressing pulmonary fibrosis. Video abstract.

The potential benefit of endothelin receptor antagonists' therapy in idiopathic pulmonary fibrosis: A meta-analysis of results from randomized controlled trials

BACKGROUND

Fibrotic diseases take a very heavy toll in terms of morbidity and mortality equal to or even greater than that caused by metastatic cancer. This meta-analysis aimed to evaluate the effect of endothelin receptor antagonists on idiopathic pulmonary fibrosis.

METHOD

A systematic search of the clinical trials from the Medline, Google Scholar, Cochrane Library, and PubMed electronic databases was performed. Stata version 12.0 statistical software (Stata Crop LP, College Station, TX) was adopted as statistical software.

RESULT

A total of 5 studies, which included 1500 participants. Our analysis found there is no significant difference between using the endothelin receptor antagonists' group and placebo groups regarding the lung function via estimating both the change of forced vital capacity from baseline and DLco index. Exercise capacity and serious adverse effects are taken into consideration as well; however, there is still no significant change between the 2 groups.

CONCLUSION

This meta-analysis provides insufficient evidence to support that endothelin receptor antagonists' administration provides a benefit among included participants who encounter idiopathic pulmonary fibrosis.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Role of epithelial-endothelial cell interaction in the pathogenesis of SARS-CoV-2 infection

Background

The coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to threaten public health globally. Patients with severe COVID-19 disease progress to acute respiratory distress syndrome, with respiratory and multiple organ failure. It is believed that dysregulated production of proinflammatory cytokines and endothelial dysfunction contribute to the pathogenesis of severe diseases. However, the mechanisms of SARS-CoV-2 pathogenesis and the role of endothelial cells are poorly understood.

Methods

Well-differentiated human airway epithelial cells were used to explore cytokine and chemokine production after SARS-CoV-2 infection. We measured the susceptibility to infection, immune response, and expression of adhesion molecules in human pulmonary microvascular endothelial cells (HPMVECs) exposed to conditioned medium from infected epithelial cells. The effect of imatinib on HPMVECs exposed to conditioned medium was evaluated.

Results

We demonstrated the production of interleukin-6, interferon gamma-induced protein-10, and monocyte chemoattractant protein-1 from the infected human airway cells after infection with SARS-CoV-2. Although HPMVECs did not support productive replication of SARS-CoV-2, treatment of HPMVECs with conditioned medium collected from infected airway cells induced an upregulation of proinflammatory cytokines, chemokines, and vascular adhesion molecules. Imatinib inhibited the upregulation of these cytokines, chemokines, and adhesion molecules in HPMVECs treated with conditioned medium.

Conclusions

We evaluated the role of endothelial cells in the development of clinical disease caused by SARS-CoV-2 and the importance of endothelial cell–epithelial cell interaction in the pathogenesis of human COVID-19 diseases.

The importance of interventional timing in the bleomycin model of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a complex disease of unknown aetiology, which makes drug development challenging. Single administration of bleomycin directly to the lungs of mice is a widely used experimental model for studying pulmonary fibrogenesis and evaluating the effect of therapeutic antifibrotic strategies. The model works by inducing an early inflammatory phase, which transitions into fibrosis after 5-7 days. This initial inflammation makes therapeutic timing crucial. To accurately assess antifibrotic efficacy, the intervention should inhibit fibrosis without impacting early inflammation.Studies published between 2008 and 2019 using the bleomycin model to investigate pulmonary fibrosis were retrieved from PubMed, and study characteristics were analysed. Intervention-based studies were classified as either preventative (starting <7 days after bleomycin installation) or therapeutic (>7 days). In addition, studies were cross-referenced with current major clinical trials to assess the availability of preclinical rationale.A total of 976 publications were evaluated. 726 investigated potential therapies, of which 443 (61.0%) were solely preventative, 166 (22.9%) were solely therapeutic and 105 (14.5%) were both. Of the 443 preventative studies, only 70 (15.8%) characterised inflammation during the model's early inflammatory phase. In the reported 145 IPF clinical trials investigating 93 compounds/combinations, only 25 (26.9%) interventions had any preclinical data on bleomycin available on PubMed.Since 2008, we observed a shift (from <5% to 37.4%) in the number of studies evaluating drugs in the therapeutic setting in the bleomycin model. While this shift is encouraging, further characterisation of early inflammation and appropriate preclinical therapeutic testing are still needed. This will facilitate fruitful drug development in IPF, and more therapeutic strategies for patients with this devastating disease.

Arg mediates LPS-induced disruption of the pulmonary endothelial barrier

Acute Respiratory Distress Syndrome (ARDS) is a devastating disease process that involves dysregulated inflammation and decreased alveolar-capillary barrier function. Despite increased understanding of the pathophysiology, no effective targeted therapies exist to treat ARDS. Recent preclinical studies suggest that the multi-tyrosine kinase inhibitor, imatinib, which targets the Abl kinases c-Abl and Arg, has the potential to restore endothelial dysfunction caused by inflammatory agonists. Prior work demonstrates that imatinib attenuates LPS (lipopolysaccharide)-induced vascular leak and inflammation; however, the mechanisms underlying these effects remain incompletely understood. In the current study, we demonstrate that imatinib inhibits LPS-induced increase in the phosphorylation of CrkL, a specific substrate of Abl kinases, in human pulmonary endothelial cells. Specific silencing of Arg, and not c-Abl, attenuated LPS-induced pulmonary vascular permeability as measured by electrical cellular impedance sensing (ECIS) and gap formation assays. In addition, direct activation of Abl family kinases with the small molecule activator DPH resulted in endothelial barrier disruption that was attenuated by Arg siRNA. In complementary studies to characterize the mechanisms by which Arg mediates endothelial barrier function, Arg silencing was found to inhibit LPS-induced disruption of adherens junctions and phosphorylation of myosin light chains (MLC). Overall, these results characterize the mechanisms by which imatinib protects against LPS-induced endothelial barrier disruption and suggest that Arg inhibition may represent a novel strategy to enhance endothelial barrier function.

Imatinib-loaded gold nanoparticles inhibit proliferation of fibroblasts and macrophages from systemic sclerosis patients and ameliorate experimental bleomycin-induced lung fibrosis

Interstitial lung involvement in Systemic Sclerosis (SSc-ILD) is a complication with high morbidity and mortality. Specifically, engineered gold nanoparticles (GNPs) are proposed as targeted delivery system increasing efficacy of drugs with antifibrotic effect, such as tyrosine kinases. We aimed to test in vitro and in vivo the activity of targeted Imatinib (Im)-loaded GNP on SSc-ILD patients derived cells and in experimental model of lung fibrosis. GNPs functionalized with anti-CD44 and loaded with Im (GNP-HCIm) were synthesized. Lung fibroblasts (LFs) and alveolar macrophages from bronchoalveolar lavage fluids of SSc-ILD patients were cultured in presence of nanoparticles. GNP-HCIm significantly inhibited proliferation and viability inducing apoptosis of LFs and effectively reduced IL-8 release, viability and M2 polarization in alveolar macrophages. Anti-fibrotic effect of tracheal instilled GNP-HCIm was evaluated on bleomycin lung fibrosis mouse model comparing effect with common route of Im administration. GNP-HCIm were able to reduce significantly lung fibrotic changes and collagen deposition. Finally, electron microscopy revealed the presence of GNPs inside alveolar macrophages. These data support the use of GNPs locally administered in the development of new therapeutic approaches to SSc-ILD.

Effect of dermatan sulphate on a C57-mouse model of pulmonary fibrosis

OBJECTIVE

To test the antifibrotic effect of dermatan sulphate in a bleomycin-induced mouse model of pulmonary fibrosis.

METHODS

C57 mice were randomly divided into four experimental groups: saline-treated control group, bleomycin-induced fibrosis group, prednisolone acetate group and dermatan sulphate group. Lungs were assessed using the lung index, and the extent of interstitial fibrosis was graded using histopathological observation of haematoxylin & eosin-stained lung tissue. Lung tissue hydroxyproline levels and blood fibrinogen levels were measured using a hydroxyproline colorimetric kit and the Clauss fibrinogen assay, respectively. Tissue-type plasminogen activator (tPA) was measured using a chromogenic tPA assay kit.

RESULTS

Lung index values were significantly lower in the dermatan sulphate group versus the fibrosis group. Histopathological analyses revealed that dermatan sulphate treatment ameliorated the increased inflammatory cell infiltration, and attenuated the reduction in interstitial thickening, associated with bleomycin-induced fibrosis. Hydroxyproline and fibrinogen levels were decreased in the dermatan sulphate group versus the fibrosis model group. Dermatan sulphate treatment was associated with increased tPA levels versus controls and the fibrosis group.

CONCLUSIONS

Damage associated with bleomycin-induced pulmonary fibrosis was alleviated by dermatan sulphate.

Imatinib may reduce chemotherapy-induced pneumonitis. A report on four cases from the SWENOTECA

BACKGROUND

An increasing number of anticancer drugs have been reported to cause pneumonitis. Chemotherapy-induced pneumonitis may cause severe morbidity and event death. As there has been a lack of effective treatment, new treatment strategies are needed. A previous case report has indicated that imatinib may be useful.

PATIENT AND METHODS

The SWENOTECA experience of four cases with severe life-threatening chemotherapy-induced pneumonitis treated with imatinib is presented.

RESULTS

All four patients responded to treatment with imatinib.

CONCLUSIONS

Imatinib appears to be an effective treatment of severe chemotherapy-induced pneumonitis in germ cell cancer patients.

Lung Oxidative Stress, DNA Damage, Apoptosis, and Fibrosis in Adenine-Induced Chronic Kidney Disease in Mice

It is well-established that there is a crosstalk between the lung and the kidney, and several studies have reported association between chronic kidney disease (CKD) and pulmonary pathophysiological changes. Experimentally, CKD can be caused in mice by dietary intake of adenine. Nevertheless, the consequence of such intervention on the lung received only scant attention. Here, we assessed the pulmonary effects of adenine (0.2% w/w in feed for 4 weeks)-induced CKD in mice by assessing various physiological histological and biochemical endpoints. Adenine treatment induced a significant increase in urine output, urea and creatinine concentrations, and it decreased the body weight and creatinine clearance. It also increased proteinuria and the urinary levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. Compared with control group, the histopathological evaluation of lungs from adenine-treated mice showed polymorphonuclear leukocytes infiltration in alveolar and bronchial walls, injury, and fibrosis. Moreover, adenine caused a significant increase in lung lipid peroxidation and reactive oxygen species and decreased the antioxidant catalase. Adenine also induced DNA damage assessed by COMET assay. Similarly, adenine caused apoptosis in the lung characterized by a significant increase of cleaved caspase-3. Moreover, adenine induced a significant increase in the expression of nuclear factor erythroid 2–related factor 2 (Nrf2) in the lung. We conclude that administration of adenine in mice induced CKD is accompanied by lung oxidative stress, DNA damage, apoptosis, and Nrf2 expression and fibrosis.

Reduced expression of BMP3 contributes to the development of pulmonary fibrosis and predicts the unfavorable prognosis in IIP patients

Idiopathic pulmonary fibrosis (IPF) and idiopathic nonspecific interstitial pneumonia (INSIP) are two related diseases involving varying degrees of pulmonary fibrosis with no effective cure. Bone morphogenetic protein 3 (BMP3) is a member of the transforming growth factor-β (TGF-β) super-family, which has not been implicated in pulmonary fibrosis previously. In this study, we aimed to investigate the potential role of BMP3 playing in pulmonary fibrosis from clinical diagnosis to molecular signaling regulation. RNA sequencing was performed to explore the potential biomarker of IIP patients. The expression of BMP3 was evaluated in 83 cases of IPF and INSIP by immunohistochemistry. The function of BMP3 was investigated in both fibroblast cells and a bleomycin-induced murine pulmonary fibrosis model. The clinical relevance of BMP3 expression were analyzed in 47 IIP patients, which were included in 83 cases and possess more than five-year follow-up data. Both RNA-sequencing and immunohistochemistry staining revealed that BMP3 was significantly down-regulated in lung tissues of patients with IPF and INSIP. Consistently, lower expression of BMP3 also was found in pulmonary fibrotic tissues of bleomycin-induced mice model. Up-regulation of BMP3 prevented pulmonary fibrosis processing through inhibiting cellular proliferation of fibroblasts as well as TGF-β1 signal transduction. Finally, the relatively higher expression of BMP3 in IPF patients was associated with less/worse mortality. Intravenous injection of recombinant BMP3. Taken together, our results suggested that the low expression level of BMP3 may indicate the unfavorable prognosis of IPF patients, targeting BMP3 may represent a novel potential therapeutic method for pulmonary fibrosis management.