Pulmonary fibrosis and COVID-19: the potential role for antifibrotic therapy

Targeting endothelial cells: A novel strategy for pulmonary fibrosis treatment

Endothelial cells (ECs) are a monolayer of flat cells lining the inner surfaces of blood and lymphatic vessels. They play a key role in many physiological and pathological processes. Specifically, they maintain vascular permeability and structural stability and participate in immune responses, inflammation, coagulation, and other vital functions. ECs play a decisive role in various age-related diseases; however, their involvement in pulmonary fibrosis (PF) remains poorly understood. PF refers to a group of chronic interstitial lung diseases characterised by progressive scarring of the pulmonary parenchyma, primarily caused by aberrant tissue repair mechanisms. These changes lead to irreversible loss of lung function. Although the exact pathophysiological mechanism underlying PF has not yet been elucidated, recent studies have indicated that ECs may play a pivotal role in PF. This review outlines the involvement of pulmonary vascular ECs in PF, focusing on the regulation of vascular remodelling and endothelial barrier integrity and on the maintenance of angiogenesis through EC-specific markers, such as vascular endothelial growth factor. This review also explores processes such as endothelial-to-mesenchymal transition, immune cell interactions, anti-EC antibody reactions, metabolic dysregulation, and cellular senescence. By elucidating recent advancements in understanding the role of ECs in PF and examining drugs targeting ECs for the treatment of PF, this study provides novel insights into the pathological mechanisms of PF and the development of endothelium-based therapeutic agents.

MBD2 promotes epithelial-to-mesenchymal transition (EMT) and ARDS-related pulmonary fibrosis by modulating FZD2

OBJECTIVE

To investigate the role and underlying mechanism of Methyl-CpG binding domain protein 2 (MBD2) in the pathogenesis of acute respiratory distress syndrome (ARDS)-related pulmonary fibrosis.

METHODS

Murine models for ARDS-related pulmonary fibrosis were established in wildtype or MBD2 knockout mice, expressions of MBD2 were determined with immunohistochemistry (IHC), immunofluorescence, and western blot. Epithelial-to-mesenchymal transition (EMT) was detected with determined with decreased expression of E-cadherin and increased expressions of N-cadherin, Vimentin, and α-smooth muscle actin (α-SMA). Transforming growth factor β (TGF-β) treated mouse lung epithelial-12 (MLE-12) cells and primary human type II alveolar epithelial cells were applied to establish in vitro model for EMT. Transcriptional sequencing with RNA-Seq and Chromatin immunoprecipitation (ChIP) assay were used to explore the potential targets of MBD2. Single cell sequencing data and Human pulmonary fibrosis samples were analyzed.

RESULTS

Bleomycin (BLM) and lipopolysaccharide (LPS) induced EMT, pulmonary fibrosis, and increased expression of MBD2 in alveolar epithelial cells of mice, and MBD2 knockout significantly alleviated BLM- and LPS-induced pulmonary fibrosis and EMT. TGF-β induced EMT and elevated MBD2 expressions in alveolar epithelial cells, which was mitigated by MBD2 knockdown and aggravated by MBD2 overexpression. Frizzled 2 (FZD2) was found to be the potential target of MBD2. Single-cell sequencing analysis of ARDS patients suggested elevated expression of MBD2 in alveolar epithelial cells, and MBD2 expression was elevated in the lungs of patients with pulmonary fibrosis.

CONCLUSION

Our results indicated that MBD2 could promote EMT and ARDS-related pulmonary fibrosis, potentially by modulating the expression of FZD2.

Cardiopulmonary function alterations in mild and moderate SARS-CoV-2 patients: a longitudinal comparison of pre-infection and early recovery phases

The purpose of this study is to compare and analyze the changes of CPET and pulmonary function indexes in patients with mild and moderate SARS-CoV-2 before infection and in the early recovery period, and to explore the influence of SARS-CoV-2 on cardiopulmonary fitness and its pathogenesis. Clinical data of 39 cases are collected, and paired analyses of CPET and pulmonary ventilation parameters before and after infection are performed using software SPSS. Bivariate correlations are analyzed for days post-infection, VO2peak decline rate, VO2peak/kg after infection, AHRR decline rate, and residual symptom count. The results show that VO2peak, VO2peak/kg, and AT significantly decreased after infection. The VE/VCO2 slope increased, while PetCO2, VEpeak, and VE/VCO2 minimum showed reductions. FVC, FEV1, and FEV1/FVC remained unchanged. OUES significantly declined, along with AHRR and HRpeak, although no significant differences are observed in HRrest, HRR-1 min, and HRR-2 min. The number of residual symptoms is significantly correlated with VO2peak/kg and its decline rate, but not with infection duration. Additionally, the decline rate of VO2peak/kg is strongly associated with post-infection time and post-infection VO2peak/kg. VO2/HR and power also decreased significantly. Moreover, after SARS-CoV-2 infection, cardiopulmonary function, including cardiac chronotropic and muscle function, is significantly impaired in mild and moderate patients. Residual symptoms are closely linked to cardiopulmonary function. Given the large proportion of mild and moderate cases, these findings offer valuable insights for developing targeted interventions to prevent further symptom progression and improve cardiopulmonary health in this population.

Post-COVID-19 lung disease: utility of biochemical and imaging markers in uncovering residual lung inflammation and monitoring anti-inflammatory therapy, a prospective study

PURPOSE

Post-COVID-19 lung disease (PCLD) is a significant concern following the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. PCLD encompasses persistent debilitating respiratory symptoms and radiological changes beyond the acute disease phase. It highlights the ongoing search to identify and manage lingering diseases. This prospective study utilizes F18-Fludeoxyglucose (FDG) PET/CT to identify residual inflammatory lung lesions in PCLD. Treatment response was assessed after anti-inflammatory and antifibrotic therapies.

MATERIALS AND METHODS

Thirty patients post-severe COVID-19 pneumonia enrolled. They underwent baseline 18F-FDG PET/CT scans to unveil residual lung inflammation lesions on FDG and CT. They received antifibrotic (Pirfenidone) and anti-inflammatory (Methylprednisolone) drugs for 6-12 weeks. They were followed up for clinical, biochemical, and imaging treatment responses.

RESULTS

Baseline 18F-FDG PET/CT revealed ongoing lung inflammation in all PCLD (mean SUVmax: 3.8 ± 2.3 and number of segments: 8±3 ). The mean CT severity score was 17.7 ± 3.4 with moderate (n = 16) or severe (n = 14) disease involvement. Mild, moderate, and severe 18F-FDG PET/CT categories were noted in the 8, 14, and 8 patients, respectively. Following treatment, a PET scan showed a significant decrease in disease extent (segments) and severity (FDG uptake) and an improvement in disease grading on imaging (97% of patients). In PET concordance, there was a significant clinical and radiological improvement with a fall in inflammatory markers (p < 0.005). Serum Ferritin and total leukocyte counts were significantly associated with PCLD severity on 18F-FDG PET/CT(p < 0.05).

CONCLUSION

This prospective study identifies and quantifies ongoing significant residual lung inflammation in PCLD on 18F-FDG PET/CT. Anti-inflammatory and antifibrotic drug therapy led to clinical and radiological improvement. 18F-FDG PET/CT as a non-invasive biomarker helped manage and follow up PCLD patients.

CLINICAL TRIAL NUMBER

Not applicable.

Pulmonary fibrosis: from mechanisms to therapies

Pulmonary fibrosis (PF) is a chronic, progressive interstitial lung disease characterized by excessive deposition of extracellular matrix (ECM) and abnormal fibroblast proliferation, which is mainly caused by air pollution, smoking, aging, occupational exposure, environmental pollutants exposure, and microbial infections. Although antifibrotic agents such as pirfenidone and nintedanib, approved by the United States (US) Food and Drug Administration (FDA), can slow the decline in lung function and disease progression, their side effects and delivery inefficiency limit the overall prognosis of PF. Therefore, there is an urgent need to develop effective therapeutic targets and delivery approaches for PF in clinical settings. This review provides an overview of the pathogenic mechanisms, therapeutic drug targeting signaling pathways, and promising drug delivery strategies for treating PF.

Inhalable myofibroblast targeting nanoparticles for synergistic treatment of pulmonary fibrosis

Pulmonary fibrosis (PF) is a life-threatening interstitial lung disease, characterized by excessive fibroblast activation and collagen deposition, leading to progressive pulmonary function decline and limited therapeutic efficacy. Here, the inhalable, myofibroblast-targeted, and pH-responsive liposomes (FL-NI) were developed for effective codelivery of nintedanib, a mainstream antifibrotic drug in clinic, and siIL11, a small interfering RNA that silences the key profibrosis cytokine IL-11. Notably, FL-NI achieved a 117.8% increase in pulmonary drug delivery by noninvasive inhalation and a 71.5% increase in delivery specifically to fibroblast activation protein-positive myofibroblasts while reducing nonspecific immune cell and epithelial uptake by 29.8 and 55.8%, respectively. The accurate inhalation codelivery of nintedanib and siIL11 into myofibroblasts achieved synergistic effects, effectively enhanced myofibroblast deactivation, reduced pathological collagen deposition by 50.8%, and promoted epithelial tissue repair. FL-NI remodeled the aberrant immune microenvironment without inducing systemic toxicities. Therefore, this work demonstrated the notable potential for this pluripotent strategy for improving PF outcomes and its promising clinical translation.

Runt-related transcription factors: from pathogenesis to therapeutic targets in multiple-organ fibrosis

Fibrosis is a partially manageable process that leads to scarring and tissue hardening by prompting myofibroblasts to deposit significant amounts of extracellular matrix (ECM) following injury. It results in detrimental consequences and pathological characteristics, which hinder the functioning of associated organs and increase mortality rates. Runt-related transcription factors (RUNX) are part of a highly conserved family of heterodimer transcription factors, comprising RUNX1, RUNX2, and RUNX3. They are involved in several biological processes and undergo various forms of post-translational modification. RUNX regulates multiple targets and pathways to impact fibrosis, indicating promise for clinical application. Therefore, its significance in the fibrosis process should not be disregarded. The review begins with an objective description of the structure, transcriptional mechanism, and biological function of RUNX1, RUNX2, and RUNX3. A subsequent analysis is made of their physiological relationship with heart, lung, kidney, and liver, followed by a focus on the signaling mechanism of RUNX in regulating fibrosis of these organs. Furthermore, potential agents or drugs targeting RUNX for treating organ fibrosis are summarized, along with an evaluation of the therapeutic prospects and potential value of RUNX in fibrosis. Further research into RUNX could contribute to the development of novel therapeutic approaches for fibrosis.

"Capture and kill" circulating fibrocytes by cisplatin prodrug loaded albumin disrupt the progress of pulmonary fibrosis in mice

Pulmonary fibrosis (PF) is a progressive chronic disease characterized by a continuous decline in lung function, for which effective therapies remain elusive. Increasing evidence suggests that the recruitment of fibrocytes from the circulatory system to lungs plays a pivotal role in the pathogenesis of PF. Once into the lungs, these fibrocytes differentiate into myofibroblasts, the primary producers of extracellular collagen. Given the difficulty in reversing the disease course, targeting this key mechanism in the early stages of the disease presents a promising therapeutic strategy. To this end, we engineered a plerixafor (CXCR4 antagonist)-modified serum albumin delivery system loaded with a cisplatin prodrug (Cpro@P-SA). This system is specifically designed to target CXCR4-positive circulating fibrocytes after intravenous administration, enhance cellular uptake of Cpro@P-SA, and facilitate the intracellular conversion of cisplatin prodrug to exert its cytotoxic effects, thereby inducing fibrocytes apoptosis. Utilizing a bleomycin-induced PF mouse model, we have demonstrated that Cpro@P-SA maintains prolonged circulation, enabling it to selectively identify and eradicate recruiting fibrocytes with an optimized treatment regimen. Our results confirm that Cpro@P-SA can effectively reduce fibrocyte levels in the circulatory system, thereby mitigating PF symptoms and controlling disease progression, as evidenced by key biochemical markers and histological analyses. Furthermore, the safety of this designed system was validated through multiple evaluations. Consequently, Cpro@P-SA offers a novel and promising therapeutic approach for the treatment of early PF.

Macrophage Polarization in Lung Diseases: From Mechanisms to Therapeutic Strategies

Macrophages are pivotal immune cells involved in maintaining immune homeostasis and defending against pathogens. They exhibit significant plasticity and heterogeneity, enabling polarization into pro-inflammatory M1 or anti-inflammatory M2 phenotypes in response to distinct microenvironmental cues. The process of macrophage polarization is tightly regulated by complex signaling pathways and transcriptional networks. This review explores the factors influencing macrophage polarization, the associated signaling pathways, and their roles in the pathogenesis of lung diseases, including fibrosis, cancer, and chronic inflammatory conditions. By summarizing recent advances, we aim to provide insights into the immunoregulatory functions of macrophages and their therapeutic potential. Based on our review, it is believed that targeting macrophage polarization emerges as a promising approach for developing effective treatments for lung diseases, balancing inflammation and repair while mitigating disease progression.

A Novel Polysaccharide from the Flowers of Lilium lancifolium Alleviates Pulmonary Fibrosis In Vivo and In Vitro

Lily flowers are widely used in China for lung nourishment; however, their active ingredients remain unknown. To address this question, we isolated a novel polysaccharide (L005-B) from the flowers of Lilium lancifolium. Its backbone is comprised of Glcp, Galp, and 1,2-linked α-Rhap. The branch is composed of Xyl and T-α-Glcp residues substituted at the C-4 position of Rhap, along with portions of Glcp, Galp, Araf, and GlcpA residues substituted at the C-4 position of glucose or the C-3 position of galactose. Bioactivity study showed that L005-B alleviated fibrosis-associated protein (fibronectin, collagen, α-SMA) expression in TGF-β1-induced human fibroblast cells (MRC-5). Moreover, L005-B significantly inhibited the epithelial-mesenchymal transition of the human alveolar type II epithelial cell. More importantly, L005-B dramatically improved bleomycin-induced histopathological changes and attenuated the pulmonary index and hydroxyproline contents. Taken together, our findings revealed that L005-B may serve as a promising leading compound for the development of novel antipulmonary fibrosis therapeutics.

Analysis of screen-detected pulmonary nodules before and after the novel coronavirus epidemic: a multicenter retrospective cohort study

Objective

To analyze the screening results for pulmonary nodules before and after the COVID-19 epidemic to understand the influence of the COVID-19 epidemic on the detection rate of pulmonary nodules and the detection rate of high-risk pulmonary nodules.

Methods

A total of 18,906 chest CT scans were performed between March and November 2022 and between March and November 2023. Subjects from March to December 2022 were divided into the pre-epidemic group, and subjects from March to December 2023 were divided into the post-epidemic group. The detection rates of lung nodules, high risk nodules, different age groups, and gender groups were analyzed.

Results

A total of 11513 lung nodules were detected during screening. A total of 841 high risk nodules were detected, and the detection rate of solid nodules was significantly higher in the postepidemic group than in the pre-epidemic group. The detection rate of fibrotic changes was significantly higher in the postepidemic group than in the pre-epidemic group. The detection rate of pulmonary nodules is significantly higher in those aged > 51 years compared to those aged 50 years and below.

Conclusion

In the post-COVID-19 period, there has been a significant increase in the detection of solid pulmonary nodules. This increased detection rate is predominantly observed in medical patients over 51 years of age. However, the COVID-19 epidemic has not resulted in an increased detection rate of high risk nodules.

Understanding of Patients with Severe COVID-19 Using Lung Ultrasound

BACKGROUND

Lung ultrasound (LUS) has proven valuable in the initial assessment of coronavirus disease 2019 (COVID-19), but its role in detecting pulmonary fibrosis following intensive care remains unclear. This study aims to assess the presence of pulmonary sequelae and fibrosis-like changes using LUS in survivors of severe COVID-19 pneumonia one month after discharge.

METHODS

We prospectively enrolled patients with severe COVID-19 who required mechanical ventilation in the intensive care unit (ICU) and conducted LUS assessments from admission to the outpatient visit after discharge. We tracked changes in key LUS findings and applied our proprietary LUS scoring system. To evaluate LUS accuracy, we correlated measured LUS values with computed tomography scores.

RESULTS

We evaluated B-line presence, pleural thickness, and consolidation in 14 eligible patients. The LUS scores exhibited minimal changes, with values of 19.1, 19.2, and 17.5 at admission, discharge, and the outpatient visit, respectively. Notably, the number of B-lines decreased significantly, from 1.92 at admission to 0.56 at the outpatient visit (p<0.05), while pleural thickness increased significantly, from 2.05 at admission to 2.48 at the outpatient visit (p≤0.05).

CONCLUSION

This study demonstrates that LUS can track changes in lung abnormalities in severe COVID-19 patients from ICU admission through to outpatient follow-up. While pleural thickening and B-line patterns showed significant changes, no correlation was found between LUS and high-resolution computed tomography fibrosis scores. These findings suggest that LUS may serve as a supplementary tool for assessing pulmonary recovery in severe COVID-19 cases.

Determination of both the expression and serum levels of epidermal growth factor and transforming growth factor β1 genes in COVID-19

We aimed to evaluate the effects of both the expression and serum levels of Epidermal growth factor (EGF) and Transforming growth factor-β1 (TGF-β1) genes in patients with different degrees of cellular damage as mild, moderate, severe, and critical illness that can lead to fibrosis caused by SARS-CoV-2. Totally 45 individuals (male: 21(46.67%); female: 24(53.33%)) with COVID-19 infection were included in this study. Four groups were constituted as mild (n = 16)], moderate (n = 10), severe (n = 10), and critical (n = 9) according to the severity of the disease. Blood samples were drawn from the patients, and all of the hemograms, EGF and TGFβ1 gene expression, and serum levels were evaluated. The mean age of individuals was 57.311 ± 18.383 (min: 28, max: 94). Significant differences were found among the groups for PLT (χ2 = 9.955; p = 0.019), CRP (χ2 = 7.693; p = 0.053), Ferritin (χ2 = 22.196; p < 0.001), D-dimer (χ2 = 21.982; p = 0.000), LDH (χ2 = 21.807; p < 0.001) and all these parameters (exclude PLT in severe groups) was increased depending on the severity of the disease. Additionally, significant differences were detected for EGF (χ2 = 29.528; p < 0.001), TGFB1 (χ2 = 28.981; p < 0.001) expression (that increased depending on the disease severity), and EGF (χ2 = 7.84; p = 0.049), TGFB1 (χ2 = 17.451; p = 0.001) serum concentration levels (that decreased depending on the disease severity). This study found statistically significant differences for both EGF 2-ΔΔCt. TGFβ1 2-ΔΔCt and EGF, TGFβ1 serum concentration values among all patient groups. As disease severity increased, EGF 2-ΔΔCt. TGFβ1 2-ΔΔCt levels increased, while EGF and TGFβ1 serum concentration levels decreased. Perhaps this study will be useful in managing COVID-19 infection severity and pulmonary fibrosis cases secondary to COVID-19.

Increased circulating levels of SP-D and IL-10 are associated with the development of disease severity and pulmonary fibrosis in patients with COVID-19

Background

Patients with severe COVID-19 can rapidly develop acute respiratory distress syndrome (ARDS), which further increases the risk of developing pulmonary fibrosis. The exact role of macrophage polarization and different cytokine production in the pathophysiology associated with COVID-19 induced ARDS or pulmonary fibrosis is unknown. It is necessary to identify potential biomarkers that can predict the progress of pulmonary fibrosis or other adverse consequences.

Methods

We analyze the plasma samples obtained from healthy individuals and COVID-19 patients who were stratified according to the disease severity and fibrotic-like changes on chest computed tomography (CT) scans. Surfactant Protein D (SP-D), Matrix Metalloproteinase 8 (MMP8), Krebs von den lungen-6 (KL-6), Angiotensin-Converting Enzyme 2 (ACE2), and macrophage polarization-related biomarkers were determined by ELISA. Data were collected and evaluated using regression models and receiver operating characteristic (ROC) curves.

Results

The plasma levels of SP-D, MMP8 in patients with ARDS were higher than those of non-ARDS patients. Patients with pulmonary fibrosis had higher plasma levels of SP-D compared to those without fibrotic changes. Among the biomarkers indicative of macrophage polarization, compared to non-ARDS patients, a significant increase in IL-10, Inducible nitric oxide synthase (iNOS), and Arginase-1 (Arg-1) were observed in ARDS patients, while Tumor necrosis factor-α (TNF-α) was decreased. The plasma level of IL-10 was also elevated in patients with fibrotic changes on CT, and was positively correlated with ACE2 and Arg-1. ROC curve results uncovered that SP-D showed higher efficacy in predicting pulmonary fibrosis and ARDS compared to other inflammatory markers. And IL-10 had similar predictive value with traditional inflammatory indicators such as CRP and PCT.

Conclusion

SP-D and IL-10 exhibited certain predictive abilities for the development of ARDS and pulmonary fibrosis in patients with COVID-19. The determination of these cytokines upon admission is crucial for evaluating the prognosis of COVID-19 patients.

COVID-19 related complications

The COVID-19 pandemic has significantly impacted global healthcare systems, revealed vulnerabilities and prompted a re-evaluation of medical practices. Acute complications from the virus, including cardiovascular and neurological issues, have underscored the necessity for timely medical interventions. Advances in diagnostic methods and personalized therapies have been pivotal in mitigating severe outcomes. Additionally, Long COVID has emerged as a complex challenge, affecting various body systems and leading to respiratory, cardiovascular, neurological, psychological, and musculoskeletal problems. This broad spectrum of complications highlights the importance of multidisciplinary management approaches that prioritize therapy, rehabilitation, and patient-centered care. Vulnerable populations such as paediatric patients, pregnant women, and immunocompromised individuals face unique risks and complications, necessitating continuous monitoring and tailored management strategies to reduce morbidity and mortality associated with COVID-19.

Citrus pectin-coated inhalable PLGA nanoparticles for treatment of pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic interstitial disorder of the respiratory system that can be debilitating as it progresses and has experienced a slow rise in incidence in past years. Treatment is complicated by the complex aetiology of the disease and the off-target effects of the two FDA-approved therapeutics available on the market: pirfenidone and nintedanib. In this work, we propose a multipurpose nanoparticle system consisting of poly(lactic-co-glycolic) acid polymer (PLGA) and a coating of citrus pectin (CP) for galectin-3 targeting and anti-fibrotic therapy. Pectin from citrus peels has been observed to have anti-fibrotic activity in a range of fibrotic tissues, causing a decrease in the expression and activity of galectin-3: a key, upregulated marker of fibrosis. We show that the CP-PLGA nanoparticles (NPs) have an average diameter of 340.5 ± 10.6 nm, compatible with inhalation and retention in the deep lung, and that CP constitutes, on average, 40.3% of the final CP-PLGA formulation. The NPs are well-tolerated by MRC-5 lung fibroblasts up to 2 mg mL-1. We demonstrate the NPs' ability to target transforming growth factor β (TGFβ)-treated fibrotic MRC-5 cells in a specific, dose-dependent manner, saturating at approx. 250 μg mL-1in vitro, and that our NPs have potent anti-fibrotic activity in vivo in particular, reversing bleomycin-induced fibrosis in mouse lungs, accompanied by marked reduction in profibrotic markers including collagen 1, fibronectin, α-smooth muscle actin, β-catenin and galectin-3. In all, we present an inherently therapeutic inhalable nanocarrier for galectin-3 targeting and anti-fibrotic therapy. We envision this carrier to be doubly effective against fibrotic lung tissue when combined with an encapsulated anti-fibrotic drug, improving overall/total therapeutic efficacy and patient compliance via the reduction of off-target effects and additive therapeutic effects.

Global research landscape on nanotechnology in acute lung injury: a bibliometric analysis

Background

Acute lung injury is a common respiratory emergency that seriously affects the life, health and quality of life of patients, especially after the global COVID-19 pneumonia. The application of nanotechnology in acute lung injury is promising. In response to the knowledge explosion resulting from rapid publication growth, we applied bibliometric analysis to explore the research profile and thematic trends in the field.

Methods

Articles and reviews related to nanotechnology in acute lung injury from 2004 to 2023 were searched. Java-based Citespace, VOSviewer, and R software-based Bibiometrix were used to systematically evaluate publications by spatiotemporal distribution, author distribution, subject categories, topic distribution, references, and keywords.

Results

A total of 1,347 publications were included. The number of papers related to nanotechnology in acute lung injury has grown exponentially over the past 20 years. China was the most productive country out of all 53 countries, followed by the United States. The Chinese Academy of Sciences was the most productive institution with 76 papers. PARTICLE AND FIBRE TOXICOLOGY was the most productive journal. The top five high-frequency keywords were inflammation, oxidative stress, toxicity, in vitro, respiratory-distress-syndrome. And the top five emerging keywords were delivery, covid-19, extracellular vesicles, therapy, sars-cov-2. Drug delivery are the focus of current research. Two emerging research areas represented the development trends: novel nanocarriers with higher efficiency and lower biotoxicity, and the other is research related to impact of nanomaterials in the progression of acute lung injury.

Conclusion

The field of nanotechnology in acute lung injury has been in a period of rapid development in the last three years. Delivery,targeted delivery and exosm have been the focus of current research in this field. Two emerging research areas represented the development trends:novel nanocarriers with higher efficiency and lower biotoxicity such as extracellular vesicles, exosomes and solid lipid nanoparticles, and the other is research related to impact of nanomaterials in the progression of acute lung injury.

Effect of Alpinia officinarum Rhizome extract on experimentally induced lung fibrosis: The pertinent role of Sirt1 and Nrf2 antioxidant pathways

BACKGROUND

Pulmonary fibrosis (PF) is a frequently reported COVID-19 sequela. It is a progressive disorder characterized by respiratory failure and death. The properties of Alpinia officinarum Rhizomes (AO) make it a highly potent antioxidant, anti-inflammatory, and antifibrotic agent. This study has evaluated AO's protective effects on bleomycin-induced PF in rats and investigated the underlying mechanisms.

MATERIAL AND METHODS

Bleomycin (5mg/kg, intratracheally) was used to induce PF in albino rats, and then, AO extract (200mg/kg/daily, orally) was administrated for 28days post-bleomycin-instillation. After euthanizing the rats, the biochemical, quantitative real-time polymerase chain reaction (qPCR) and histopathological examination of lung tissue were determined.

RESULTS

Findings have revealed that bleomycin significantly increased the tissue level of malondialdehyde, tumor necrosis factor-alpha, and interleukin-6, Silent information regulator 1 (Sirt1), and nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA levels. Furthermore, the total antioxidant capacity level decreased in the lungs of bleomycin-instilled rats. However, AO extract significantly decreased histopathological injuries in hematoxylin & eosin, Masson's trichrome-stained sections, inducible nitric oxide synthase and α-smooth muscle actin, transforming growth factor beta 1 immunoexpression.

CONCLUSION

Alpinia officinarum Rhizomes extract appears to protect against bleomycin-induced PF, possibly due to its antioxidant, anti-inflammatory, and antifibrotic properties.

Regorafenib as a potential drug for severe COVID-19: inhibition of inflammasome activation in mice

SARS-CoV-2 infection can lead to severe COVID-19, particularly in elderly individuals and those with compromised immunity. Cellular senescence has been implicated as a key pathogenic mechanism. This study investigated the therapeutic potential of regorafenib, a previously characterized senomorphic drug, for severe COVID-19. SARS-CoV-2 virus-infected K18-hACE2 mice, overexpressing the human ACE2 receptor, exhibited 100% mortality by 10 days post infection. Regorafenib treatment significantly improved survival rates, approximately 43% remaining alive. Mechanistically, regorafenib effectively suppressed type I and II interferon and cytokine signaling. Notably, regorafenib inhibited NLR family pyrin domain containing 3 (NLRP3) inflammasome activation, a key driver of the cytokine storm associated with severe COVID-19. Our findings elucidate the molecular mechanisms underlying therapeutic effects of regorafenib and suggest its potential use as a promising treatment option for severe COVID-19.

Droplet microfluidics: unveiling the hidden complexity of the human microbiome

The human body harbors diverse microbial communities essential for maintaining health and influencing disease processes. Droplet microfluidics, a precise and high-throughput platform for manipulating microscale droplets, has become vital in advancing microbiome research. This review introduces the foundational principles of droplet microfluidics, its operational capabilities, and wide-ranging applications. We emphasize its role in enhancing single-cell sequencing technologies, particularly genome and RNA sequencing, transforming our understanding of microbial diversity, gene expression, and community dynamics. We explore its critical function in isolating and cultivating traditionally unculturable microbes and investigating microbial activity and interactions, facilitating deeper insight into community behavior and metabolic functions. Lastly, we highlight its broader applications in microbial analysis and its potential to revolutionize human health research by driving innovations in diagnostics, therapeutic development, and personalized medicine. This review provides a comprehensive overview of droplet microfluidics' impact on microbiome research, underscoring its potential to transform our understanding of microbial dynamics and their relevance to health and disease.

Presence and Evolution of Radiological Changes at 6 and 12 Months After COVID-19 Pneumonia and Their Risk Factors

Background and Objectives: The pulmonary sequelae of COVID-19 and their evolution are of interest to the scientific community. We aimed to determine the radiological changes at 6 and 12 months after COVID-19 pneumonia, its evolution and its risk factors. Materials and Methods: This retrospective longitudinal study included adults admitted for COVID-19 pneumonia from 1 March 2020 to 30 April 2021 who had a high-resolution computed tomography (HRCT) scan at 6 months and 12 months after hospital discharge. The primary outcome was the appearance of radiological abnormalities on HRCT and the number of lung segments affected by them at 6 and 12 months, while the main explanatory variables were about the disease course, analytical parameters and treatment. Results: This study included n = 108 patients, with a mean age of 64 years. There was a decrease in the percentage of patients presenting parenchymal (93.5% to 88.9%, p < 0.001) and reticular (63% to 62%, p < 0.001) patterns on HRCT at 12 months compared to 6, and an increase in those presenting a fibrotic pattern (62% to 63.9%, p < 0.001). Ground-glass opacities were the most frequent radiological change at 6 and 12 months (91.7% and 87%, respectively). There was a significant reduction in the total number of lung segments with ground-glass opacities (445 to 382, p < 0.001) and consolidation (158 to 136, p = 0.019) and an increase in those with bronchiectasis (66 to 80, p = 0.033) between the two moments. After multivariate analysis, high-flow oxygen therapy (HFOT), highest ferritin levels, hypertension and ≥71 years showed an association with the development of subpleural parenchymal bands, consolidation, bronchiectasis and septal thickening at 6 and 12 months. Conclusions: Parenchymal patterns seem to be more frequent than reticular and fibrotic patterns after COVID-19 pneumonia. The fibrotic pattern was the only one that worsened significantly over time, with bronchiectasis being the only change that increased at 12 months. Older age, hypertension, the need for HFOT, and high levels of ferritin may be directly associated with worse radiological outcomes after COVID-19 pneumonia.

Integrating Metabolomics and Network Analyses to Explore Mechanisms of Geum japonicum var. chinense Against Pulmonary Fibrosis: Involvement of Arachidonic Acid Metabolic Pathway

Pulmonary fibrosis (PF) emerges as a significant pulmonary sequelae in the convalescent phase of coronavirus disease 2019 (COVID-19), with current strategies neither specifically preventive nor therapeutic. Geum japonicum var. chinense (GJC) is used as a traditional Chinese medicine to effectively treat various respiratory conditions. However, the protective effects of GJC against PF remains unclear. In the present study, the anti-PF effect of GJC aqueous extract was studied using a PF mouse model induced by bleomycin (BLM). To characterize the metabolite changes related to PF and reveal therapeutic targets for GJC aqueous extract, we performed metabolomic and network analysis on mice lungs. Finally, key targets were then validated by Western blotting. GJC aqueous extract effectively alleviated the onset and progression of lung fibrosis in PF mice by inhibiting inflammatory responses and regulating oxidative stress levels. Integrating serum metabolomics and network analyses showed the arachidonic acid (AA) pathway to be the most important metabolic pathway of GJC aqueous extract against PF. Further validation of AA pathway protein levels showed a significant rise in the levels of ALOX5, PTGS2, CYP2C9, and PLA2G2A in PF lungs. GJC aqueous extract treatment regulated the above changes in metabolic programming. In conclusion, GJC is a promising botanical drug to delay the onset and progression of PF mice. The primary mechanism of action is associated with the comprehensive regulation of metabolites and protein expression related to the AA metabolic pathway.

Muribaculum intestinale-derived 3-hydroxybutyric acid from Heterophyllin B attenuated pulmonary fibrosis through IDO1-mediated ferroptosis

Pulmonary fibrosis (PF) is a fatal disease with increasing incidence, poor prognosis, and unclear pathogenesis. Our previous research demonstrated the beneficial effects of the natural cyclopeptide Heterophyllin B (HB) in PF. However, the precise mechanism by which HB exerts its effects in PF remains unclear. Our study revealed HB's beneficial effects in alleviating PF symptoms and restoring the intestinal mucosal barrier. Subsequently, the microbiota-dependent antifibrotic efficacy of HB was verified using various delivery routes, antibiotic treatments, and faecal microbiota transplantation. Functionally, 16S rRNA sequencing, untargeted metabolomics, and co-incubation experiments revealed that the antifibrotic efficacy of HB was primarily contingent on the enrichment of Muribaculum intestinale and its metabolite, 3-hydroxybutyric acid. Mechanistically, indoleamine 2,3- dioxygenase 1 (IDO1)-mediated ferroptosis was identified as a pivotal process in initiating PF, and the anti-fibrotic efficacy of HB relies on suppressing IDO1-mediated ferroptosis. Conversely, IDO1 deficiency alleviated the symptoms of bleomycin-induced PF and ferroptosis in mice. Coincidentally, both IDO1 overexpression and ferroptosis were observed in the pulmonary tissue of patients with idiopathic PF. Collectively, this study revealed that HB alleviates PF by eliminating intestinal microecology and metabolism and highlights the feasibility of targeting IDO1 for PF treatment.

Anti-PL-7/PL-12 antisynthetase syndrome associated with interstitial lung disease following SARS-COV-2 infection and vaccination: A case study review

Cumulative evidence suggests a link between specific autoimmune diseases (AD), including idiopathic inflammatory myopathies (IIM), and SARS-CoV-2 infection or COVID-19 vaccination. Anti-synthetase syndrome (ASS), a subset of IIM, is defined by the presence of autoantibodies against aminoacyl-tRNA synthetase (anti-ARS) and is strongly associated with interstitial lung disease (ILD), a major contributor to severe complications and reduced survival. We present four clinical cases of patients who developed autoantibodies against threonyl (PL-7) and alanyl (PL-12) synthetases associated with ASS-ILD shortly after SARS-CoV-2 infection or COVID-19 vaccination. Anti-ARS autoantibodies were identified using three complementary methods: immunoblotting, western blotting (WB) and the method considered the gold standard, immunoprecipitation (IP), which ensures accurate interpretation of results. The study highlights the clinical and pathogenic overlap between ASS-ILD and SARS-CoV-2-related lung involvement.Both conditions share similar high-resolution computed tomography (HRCT) patterns, including inflammation and pulmonary fibrosis (PF), driven by IFN-γ signaling, which complicates accurate diagnosis. Our results provide novel insights into the temporal association of SARS-CoV-2 and vaccine exposure with ASS-ILD, focusing on possible molecular mimicry between viral proteins and ARS molecules as a potential mechanism. Understanding the involvement of specific anti-ARS autoantibodies (PL-7 and PL-12) and the identification of genetic predispositions (HLA-B∗08:01 and HLA-DRB1∗03:01) in these patients may be key to underpinning these autoimmune manifestations. The study underscores the importance of a multidisciplinary approach and vigilant follow-up to optimize diagnosis and management. Further research is essential to elucidate the causal relationships and molecular mechanisms behind these observations.

Exploring TβRI inhibitors from Arenaria kansuensis based on 3D-QSAR, molecular docking and molecular dynamics simulation methods and its anti-pulmonary fibrosis molecular mechanism validation

ETHNOPHARMACOLOGICAL RELEVANCE

Pulmonary fibrosis (PF) is a kind of interstitial lung disease that seriously threatens human life and health. Up to now, there is no specifically therapeutic drug. Arenaria kansuensis, a typical Tibetan medicine, has been previously proved to have anti-PF pharmacological activity by our group. However, the specific target and molecular mechanism of pharmacological active ingredients from it are still unknown.

AIM OF THE STUDY

This study aimed to explore the molecular mechanism and specific target of pharmacological active ingredients from A. kansuensis for treating PF.

MATERIALS AND METHODS

Virtual screening including 3D-QSAR, molecular docking and molecular dynamics simulation were used to screen TβRI inhibitor. CETSA experiment was used to verify the interaction between GAK (a β-carboline alkaloid isolated from A. kansuensis) and TβRI. Cell and molecular experiments including observation of cell morphology and Western blot were applied to investigate the molecular mechanism of action of GAK for treating PF. Animal experiments including physiological index, immunohistochemistry and ELISA were used to comprehensively evaluate the anti-PF effect of GAK and explore the corresponding mechanism of action.

RESULTS

Results of 3D-QSAR experiment indicated that GAK is a much stronger potential TβRI inhibitor, molecular mechanism study showed that 30 μM GAK could significantly keep TβRI more stable which indicated that the direct binding interaction between GAK and TβRI, it targetedly inhibited TβRI through forming hydrogen bonds with LYS232, SER280 and ASP351 and the binding energies is -56.05 kcal/mol. In vitro experiment showed GAK could suppress downstream signal pathways of TβRI including MAPK, PI3K/AKT and NF-κB pathways during EMT process. In vivo experiment showed that GAK could improve the survival rate and body weight of PF mice, alleviate the symptoms of histopathological severity, inflammatory cell infiltration and collagen deposition in lung tissue of PF mice through inhibiting EMT process of PF.

CONCLUSIONS

This work not only provided evidence to support GAK as a novel TβRI inhibitor for treating PF through multiple pathways, but also reveal the specific target and molecular mechanism of β-carboline alkaloids from A. kansuensis for treating PF.

The Relationship Between Differential Expression of Non-coding RNAs (TP53TG1, LINC00342, MALAT1, DNM3OS, miR-126-3p, miR-200a-3p, miR-18a-5p) and Protein-Coding Genes (PTEN, FOXO3) and Risk of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a rapidly progressive interstitial lung disease of unknown pathogenesis with no effective treatment currently available. Given the regulatory roles of lncRNAs (TP53TG1, LINC00342, H19, MALAT1, DNM3OS, MEG3), miRNAs (miR-218-5p, miR-126-3p, miR-200a-3p, miR-18a-5p, miR-29a-3p), and their target protein-coding genes (PTEN, TGFB2, FOXO3, KEAP1) in the TGF-β/SMAD3, Wnt/β-catenin, focal adhesion, and PI3K/AKT signaling pathways, we investigated the expression levels of selected genes in peripheral blood mononuclear cells (PBMCs) and lung tissue from patients with IPF. Lung tissue and blood samples were collected from 33 newly diagnosed, treatment-naive patients and 70 healthy controls. Gene expression levels were analyzed by RT-qPCR. TaqMan assays and TaqMan MicroRNA assay were employed to quantify the expression of target lncRNAs, mRNAs, and miRNAs. Our study identified significant differential expression in PBMCs from IPF patients compared to healthy controls, including lncRNAs MALAT1 (Fold Change = 3.809, P = 0.0001), TP53TG1 (Fold Change = 0.4261, P = 0.0021), and LINC00342 (Fold Change = 1.837, P = 0.0448); miRNAs miR-126-3p (Fold Change = 0.102, P = 0.0028), miR-200a-3p (Fold Change = 0.442, P = 0.0055), and miR-18a-5p (Fold Change = 0.154, P = 0.0034); and mRNAs FOXO3 (Fold Change = 4.604, P = 0.0032) and PTEN (Fold Change = 2.22, P = 0.0011). In lung tissue from IPF patients, significant expression changes were observed in TP53TG1 (Fold Change = 0.2091, P = 0.0305) and DNM3OS (Fold Change = 4.759, P = 0.05). Combined analysis of PBMCs expression levels for TP53TG1, MALAT1, miRNA miR-126-3p, and PTEN distinguished IPF patients from healthy controls with an AUC = 0.971, sensitivity = 0.80, and specificity = 0.955 (P = 6 × 10-8). These findings suggest a potential involvement of the identified ncRNAs and mRNAs in IPF pathogenesis. However, additional functional validation studies are needed to elucidate the precise molecular mechanisms by which these lncRNAs, miRNAs, and their targets contribute to PF.

Airway Basal Stem Cells Inflammatory Alterations in COVID-19 and Mitigation by Mesenchymal Stem Cells

SARS-CoV-2 infection and the resultant COVID-19 pneumonia cause significant damage to the airway and lung epithelium. This damage manifests as mucus hypersecretion, pulmonary inflammation and fibrosis, which often lead to long-term complications collectively referred to as long COVID or post-acute sequelae of COVID-19 (PASC). The airway epithelium, as the first line of defence against respiratory pathogens, depends on airway basal stem cells (BSCs) for regeneration. Alterations in BSCs are associated with impaired epithelial repair and may contribute to the respiratory complications observed in PASC. Given the critical role of BSCs in maintaining epithelial integrity, understanding their alterations in COVID-19 is essential for developing effective therapeutic strategies. This study investigates the intrinsic properties of BSCs derived from COVID-19 patients and evaluates the modulatory effects of mesenchymal stem cells (MSCs). Through a combination of functional assessments and transcriptomic profiling, we identified key phenotypic and molecular deviations in COVID-19 patient-derived BSCs, including goblet cell hyperplasia, inflammation and fibrosis, which may underlie their contribution to PASC. Notably, MSC co-culture significantly mitigated these adverse effects, potentially through modulation of the interferon signalling pathway. This is the first study to isolate BSCs from COVID-19 patients in the Chinese population and establish a COVID-19 BSC-based xenograft model. Our findings reveal critical insights into the role of BSCs in epithelial repair and their inflammatory alterations in COVID-19 pathology, with potential relevance to PASC and virus-induced respiratory sequelae. Additionally, our study highlights MSC-based therapies as a promising strategy to address respiratory sequelae and persistent symptoms.

Engineering Lipid Nanoparticles to Enhance Intracellular Delivery of Transforming Growth Factor-Beta siRNA (siTGF-β1) via Inhalation for Improving Pulmonary Fibrosis Post-Bleomycin Challenge

Background/Objectives: Transforming Growth Factor-beta (TGFβ1) plays a core role in the process of pulmonary fibrosis (PF). The progression of pulmonary fibrosis can be alleviated by siRNA-based inhibiting TGF-β1. However, the limitations of naked siRNA lead to the failure of achieving therapeutic effect. This study aimed to design lipid nanoparticles (LNPs) that can deliver siTGF-β1 to the lungs for therapeutic purposes. Methods: The cytotoxicity and transfection assay in vitro were used to screen ionizable lipids (ILs). Design of Experiments (DOE) was used to obtain novel LNPs that can enhance resistance to atomization shear forces. Meanwhile, the impact of LNPs encapsulating siTGF-β1 (siTGFβ1-LNPs) on PF was investigated. Results: When DLin-DMA-MC3 (MC3) was used as the ILs, the lipid phase ratio was MC3:DSPC:DMG-PEG2000:cholesterol = 50:10:3:37, and N/P = 3.25; the siTGFβ1-LNPs could be stably delivered to the lungs via converting the siTGFβ1-LNPs solution into an aerosol (atomization). In vitro experiments have confirmed that siTGFβ1-LNPs have high safety, high encapsulation, and can promote cellular uptake and endosomal escape. In addition, siTGFβ1-LNPs significantly reduced inflammatory infiltration and attenuated deposition of extracellular matrix (ECM) and protected the lung tissue from the toxicity of bleomycin (BLM) without causing systemic toxicity. Conclusions: The siTGFβ1-LNPs can be effectively delivered to the lungs, resulting in the silencing of TGF-β1 mRNA and the inhibition of the epithelial-mesenchymal transition pathway, thereby delaying the process of PF, which provides a new method for the treatment and intervention of PF.

Mucosal immune response in biology, disease prevention and treatment

The mucosal immune system, as the most extensive peripheral immune network, serves as the frontline defense against a myriad of microbial and dietary antigens. It is crucial in preventing pathogen invasion and establishing immune tolerance. A comprehensive understanding of mucosal immunity is essential for developing treatments that can effectively target diseases at their entry points, thereby minimizing the overall impact on the body. Despite its importance, our knowledge of mucosal immunity remains incomplete, necessitating further research. The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has underscored the critical role of mucosal immunity in disease prevention and treatment. This systematic review focuses on the dynamic interactions between mucosa-associated lymphoid structures and related diseases. We delve into the basic structures and functions of these lymphoid tissues during disease processes and explore the intricate regulatory networks and mechanisms involved. Additionally, we summarize novel therapies and clinical research advances in the prevention of mucosal immunity-related diseases. The review also addresses the challenges in developing mucosal vaccines, which aim to induce specific immune responses while maintaining tolerance to non-pathogenic microbes. Innovative therapies, such as nanoparticle vaccines and inhalable antibodies, show promise in enhancing mucosal immunity and offer potential for improved disease prevention and treatment.

Traditional Chinese Medicine Ion Introduction Therapy Reduces the Incidence of Acute Exacerbation of Idiopathic Pulmonary Fibrosis: A Prospective Cohort Study

Objective

To evaluate the effectiveness and safety of traditional Chinese medicine (TCM) ion introduction therapy in the treatment of patients with acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF).

Methods

This study adopts a prospective cohort study design, with 60 AE-IPF patients as the research subjects. Divided into an exposed group and a non exposed group, with 30 cases in each group, based on the frequency of TCM ion introduction treatment as the exposure factor. Follow-up for 1 year to observe the acute exacerbation of the patient. The main indicator is the annual incidence of acute exacerbation, and the secondary indicators are hospitalization time, readmission rate, time to first acute exacerbation, mortality rate, all-cause mortality rate, inflammatory indicators, quality of life, etc.

Results

51 patients completed a one-year clinical observation, including 27 in the exposed group and 24 in the non exposed group. Compared to the non exposed group, significant differences were observed in the annual incidence of acute exacerbation [incidence rate ratios (IRR) = 0.556, 95% CI: 0.315, 0.980; P = 0.035] and hospitalization time (P = 0.040), readmission rate (IRR = 0.533, 95% CI: 0.288, 0.988; P = 0.037), time to first acute exacerbation (P = 0.045), and quality of life (P < 0.05). However, there was no statistically significant difference in mortality rate and all-cause mortality rate between the two groups (P > 0.05).

Conclusion

Compared to the non exposed group, TCM ion introduction can reduce the annual incidence of acute exacerbation of IPF patients. Hospitalization time, readmission rate, time to first acute exacerbation, quality of life improved, but mortality rate and all-cause mortality rate did not improve.

Targeting Fibrosis: From Molecular Mechanisms to Advanced Therapies

As the final stage of disease-related tissue injury and repair, fibrosis is characterized by excessive accumulation of the extracellular matrix. Unrestricted accumulation of stromal cells and matrix during fibrosis impairs the structure and function of organs, ultimately leading to organ failure. The major etiology of fibrosis is an injury caused by genetic heterogeneity, trauma, virus infection, alcohol, mechanical stimuli, and drug. Persistent abnormal activation of "quiescent" fibroblasts that interact with or do not interact with the immune system via complicated signaling cascades, in which parenchymal cells are also triggered, is identified as the main mechanism involved in the initiation and progression of fibrosis. Although the mechanisms of fibrosis are still largely unknown, multiple therapeutic strategies targeting identified molecular mechanisms have greatly attenuated fibrotic lesions in clinical trials. In this review, the organ-specific molecular mechanisms of fibrosis is systematically summarized, including cardiac fibrosis, hepatic fibrosis, renal fibrosis, and pulmonary fibrosis. Some important signaling pathways associated with fibrosis are also introduced. Finally, the current antifibrotic strategies based on therapeutic targets and clinical trials are discussed. A comprehensive interpretation of the current mechanisms and therapeutic strategies targeting fibrosis will provide the fundamental theoretical basis not only for fibrosis but also for the development of antifibrotic therapies.

Unraveling the pathogenesis of viral-induced pulmonary arterial hypertension: Possible new therapeutic avenues with mesenchymal stromal cells and their derivatives

Pulmonary hypertension (PH) is a severe condition characterized by elevated pressure in the pulmonary artery, where metabolic and mitochondrial dysfunction may contribute to its progression. Within the PH spectrum, pulmonary arterial hypertension (PAH) stands out with its primary pulmonary vasculopathy. PAH's prevalence varies from 0.4 to 1.4 per 100,000 individuals and is associated with diverse conditions, including viral infections such as HIV. Notably, recent observations highlight an increased occurrence of PAH among COVID-19 patients, even in the absence of pre-existing cardiopulmonary disorders. While current treatments offer partial relief, there's a pressing need for innovative therapeutic strategies, among which mesenchymal stromal cells (MSCs) and their derivatives hold promise. This review critically evaluates recent investigations into viral-induced PAH, encompassing pathogens like human immunodeficiency virus, herpesvirus, Cytomegalovirus, Hepatitis B and C viruses, SARS-CoV-2, and Human endogenous retrovirus K (HERKV), with a specific emphasis on mitochondrial dysfunction. Furthermore, we explore the underlying rationale driving novel therapeutic modalities, including MSCs, extracellular vesicles, and mitochondrial interventions, within the framework of PAH management.

Idiopathic Pulmonary Fibrosis Is Associated With Type 1 Diabetes: A Two-Sample Mendelian Randomization Study

BACKGROUND

The pathogenesis of idiopathic pulmonary fibrosis (IPF) remains unclear; previous studies revealed the underlying connection between IPF and diabetes, but there is no consensual opinion. This study is aimed at examining the association between Type 1 diabetes (T1D) and IPF using Mendelian randomization (MR).

METHOD

In our two-sample MR study, we selected single nucleotide polymorphisms (SNPs) that are strongly associated with T1D in a genome-wide association study (GWAS) from IEU (dataset: ebi-a-GCST005536) and obtained their corresponding effect estimates on T1D risk in an IPF GWAS from IEU (dataset: finn-b-IPF). We conducted a multivariable Mendelian randomization (MVMR) analysis to eliminate the interference of aging.

RESULT

In the outcome of inverse-variance weighted (IVW) method, T1D showed a promoting effect on IPF (odds ratio (OR): 1.132, p = 0.005). The statistics passed the MR-PRESSO test, and no outliers were observed (global test p = 0.238). MVMR study was performed, and the aging-adjusted result remains almost the same (OR = 1.132, OR_95% CI: 1.034-1.239, p = 0.007).

CONCLUSION

Our study shows a causal relation between T1D and IPF; further investigation should be conducted.

The Cyclin-Dependent Kinase 8 Inhibitor E966-0530-45418 Attenuates Pulmonary Fibrosis In Vitro and In Vivo

Pulmonary fibrosis (PF) is a high-mortality lung disease with limited treatment options, highlighting the need for new therapies. Cyclin-dependent kinase 8 (CDK8) is a promising target due to its role in regulating transcription via the TGF-β/Smad pathway, though CDK8 inhibitors have not been thoroughly studied for PF. This study aims to evaluate the potential of E966-0530-45418, a novel CDK8 inhibitor, in mitigating PF progression and explores its underlying mechanisms. We discovered that CDK8 is upregulated in lung tissues from idiopathic pulmonary fibrosis patients and in a bleomycin-induced PF mouse model. Our study further revealed that E966-0530-45418 inhibits PF progression by attenuating the activity of the transcription factor Smad3, which is involved in TGF-β1/Smad signaling, along with RNA polymerase II to downregulate fibrosis-associated protein expression in alveolar epithelia and lung fibroblasts and consequently mitigate myofibroblast differentiation and collagen deposition. E966-0530-45418 also blocks STAT3 signaling to obstruct M2 macrophage polarization, further suppressing PF progression. Moreover, E966-0530-45418 administration ameliorated lung function deterioration and lung parenchymal destruction in the bleomycin-induced PF mouse model. These findings indicate that E966-0530-45418 holds promise as a pioneering CDK8 inhibitor for treating PF.

Persistent microbial infections and idiopathic pulmonary fibrosis - an insight into non-typeable Haemophilus influenza pathogenesis

Interstitial lung disease (ILD) is characterized by chronic inflammation and scarring of the lungs, of which idiopathic pulmonary fibrosis (IPF) is the most devastating pathologic form. Idiopathic pulmonary fibrosis pathogenesis leads to loss of lung function and eventual death in 50% of patients, making it the leading cause of ILD-associated mortality worldwide. Persistent and subclinical microbial infections are implicated in the acute exacerbation of chronic lung diseases. However, while epidemiological studies have highlighted pollutants, gastric aspirate, and microbial infections as major causes for the progression and exacerbation of IPF, the role of persistent microbial infections in the pathogenesis of IPF remains unclear. In this review, we have focused on the role of persistent microbial infections, including viral, bacterial, and fungal infections, and their mechanisms of action in the pathogenesis of IPF. In particular, the mechanisms and pathogenesis of the Gram-negative bacteria Non-typeable Haemophilus influenzae (NTHi) in ILDs are discussed, along with growing evidence of its role in IPF, given its unique ability to establish persistent intracellular infections by leveraging its non-capsulated nature to evade host defenses. While antibiotic treatments are presumably beneficial to target the extracellular, interstitial, and systemic burden of pathogens, their effects are significantly reduced in combating pathogens that reside in the intracellular compartments. The review also includes recent clinical trials, which center on combinatorial treatments involving antimicrobials and immunosuppressants, along with antifibrotic drugs that help mitigate disease progression in IPF patients. Finally, future directions focus on mRNA-based therapeutics, given their demonstrated effectiveness across a wide range of clinical applications and feasibility in targeting intracellular pathogens.

Surviving COVID-19 and Battling Fibrosis: A Retrospective Cohort Study Across Three Pandemic Waves

BACKGROUND/OBJECTIVES

We aimed to characterize the fibrosis following COVID-19 pneumonia, using quantitative analysis, after three months and subsequently, after two years of patients' release from the hospital, and to identify the risk factors for pulmonary fibrosis.

METHODS

We performed a retrospective, observational cohort study on 420 patients with severe forms of COVID-19. For all patients, we registered demographic, inflammatory and biochemical parameters, complete blood count and D-dimers; all patients underwent three computed tomography scans (at admittance, at 3 months and at 2 years).

RESULTS

We found fibrosis in 67.9% of patients at the 3-month evaluation and in 42.4% of patients at the 2-year evaluation, registering a significant decrease in the severe and moderate fibrosis cases, with a slight increase in the mild fibrosis cases. The risk of fibrosis was found to be proportional to the values of age, duration of hospital stay, inflammatory markers (ESR, fibrinogen), cytolytic markers (LDH, AST) and D-dimers. The highest correlations with lung fibrosis were registered for interstitial pulmonary involvement (for the 3-month evaluation) and total pulmonary involvement (for the 2-year evaluation).

CONCLUSIONS

Lung fibrosis represents a significant post-COVID-19 complication found in 42% of patients with severe forms of pneumonia at the 2-year evaluation. A significant overall decrease in the severity of lung fibrosis was registered at the 2-year evaluation compared to the 3-month evaluation. We consider that the amount of interstitial pulmonary involvement represents the optimal parameter to estimate the risk of lung fibrosis following SARS-CoV-2 pneumonia.

Prolonged corticosteroid therapy and lung abnormalities in patients after severe COVID-19 pneumonia

BACKGROUND

Some of the hospitalized patients after severe COVID-19 pneumonia experience significant fall in peripheral saturation despite optimal treatment. Because of immune dysregulation in COVID-19 there are indications that prolonged corticosteroids could be considered in treating patients for persistent radiological sequelae and respiratory symptoms.

OBJECTIVES

to investigate lung function and lung sequelae on high-resolution CT (HRCT) im COVID-19 patients who were treated with glucocorticoid therapy in two dose regimens with a control group of patients who did not receive additional glucocorticoid therapy.

METHODS

In this prospective cohort research we studied patients who suffered from prolonged respiratory insufficiency after severe COVID-19 pneumonia. Patients received corticosteroid therapy in two dose regimens: for 14 days and for 3 months after discharge from the hospital. Control group of patients did not receive additional corticosteroid therapy. Lung function, post-COVID-19 symptoms, and lung abnormalities on CT scans were analyzed in three months follow-up and compared with the control group of patients.

RESULTS

Patients who received prolonged corticosteroid therapy for three months did not have better CT findings of lung abnormalities, lung function, or symptoms recovery in comparison to the patients with 14 days of therapy and control group of patients. Onwards, control group had significantly fewer dyspnea symptoms (Chi-square test, p=0,04) and higher DLCO (Kruskal Wallis test, p=0,03).

CONCLUSIONS

Supplementary corticosteroid therapy for patients after severe pneumonia and prolonged respiratory insufficiency with lung abnormalities after COVID-19 did not improve lung function or lung lesions on CT.

Comparison of methotrexate and methylprednisolone as addition to antifibrotic therapy in progressive pulmonary fibrosis due to COVID-19

BACKGROUND

Post-covid pulmonary fibrosis (PCPF) is an essential cause of hypoxic respiratory failure, especially in patients with severe COVID-19 infection. In our study, we aimed to compare the effectiveness of methylprednisolone and methotrexate treatments in patients diagnosed with PCPF and in whom progression was observed despite nintedanib treatment.  Methods: Forty-eight patients diagnosed with PCPF between April 2022 and February 2023 were followed up in our study. Progressive pulmonary fibrosis was observed in 18 of these patients despite nintedanib treatment. Nintedanib + methylprednisolone treatment was started in Group 1 patients, and nintedanib + methotrexate treatment was started in Group 2 patients, and after three months, a respiratory function test (PFT), 6-minute walk test (6MWT), saturation, pulse, and side effect levels were compared.

RESULTS

In comparing the groups at the end of the 3rd month, the change in PFT parameters was higher in Group 2 patients than in Group 1 patients. However, there was no statistically significant difference. However, the increase in fingertip saturation, 6MWT levels, and decrease in pulse levels were statistically significantly different in Group 2 patients compared to Group 1 patients (p=0.001 for all).  It was observed that complaints of muscle and joint pain, weight gain, and atrophy in peripheral extremities in Group 1 patients were statistically significantly higher than in Group 2 patients (p=0.001, 0.002, 0.001, respectively).

CONCLUSION

Methotrexate can be used as an alternative to methylprednisolone in PCPF due to its low side effect profile and its effectiveness in PFT, 6MWT, and saturation levels.

Equivocating and Deliberating on the Probability of COVID-19 Infection Serving as a Risk Factor for Lung Cancer and Common Molecular Pathways Serving as a Link

The COVID-19 infection caused by SARS-CoV-2 in late 2019 posed unprecedented global health challenges of massive proportions. The persistent effects of COVID-19 have become a subject of significant concern amongst the medical and scientific community. This article aims to explore the probability of a link between the COVID-19 infection and the risk of lung cancer development. First, this article reports that SARS-CoV-2 induces severe inflammatory response and cellular stress, potentially leading to tumorigenesis through common pathways between SARS-CoV-2 infection and cancer. These pathways include the JAK/STAT3 pathway which is activated after the initiation of cytokine storm following SARS-CoV-2 infection. This pathway is involved in cellular proliferation, differentiation, and immune homeostasis. The JAK/STAT3 pathway is also hyperactivated in lung cancer which serves as a link thereof. It predisposes patients to lung cancer through myriad molecular mechanisms such as DNA damage, genomic instability, and cell cycle dysregulation. Another probable pathway to tumorigenesis is based on the possibility of an oncogenic nature of SARS-CoV-2 through hijacking the p53 protein, leading to cell oxidative stress and interfering with the DNA repair mechanisms. Finally, this article highlights the overexpression of the SLC22A18 gene in lung cancer. This gene can be overexpressed by the ZEB1 transcription factor, which was found to be highly expressed during COVID-19 infection.

ZIF-8 as efficient carriers for polysaccharide from Tetrastigma Hemsleyanum Diels et Gilg in acute lung injury induced by lipopolysaccharides

Acute lung injury (ALI) is a critical respiratory syndrome significantly impacting patient health. Tetrastigma hemsleyanum Diels et Gilg (Sanyeqing, SYQ) is a traditional Chinese medicine and its polysaccharides (SYQP) have demonstrated efficacy in counteracting lipopolysaccharide-induced ALI. This study characterized the structure of SYQP and synthesized the SYQP@ZIF-8 composite using biomimetic mineralization, evaluating encapsulation and release efficiency. The biocompatibility of SYQP@ZIF-8 in vitro was assessed by the CCK-8 colorimetric assay and hemolytic activity. Inflammatory cytokine was measured to evaluate the therapeutic effect. The efficacy of SYQP@ZIF-8 in lung injury was assessed using a mice ALI model. Characterization showed SYQP as a homogeneous α-type polysaccharide, comprising galactose, mannose, glucuronide, glucose, galacturonide, and arabinose, with a molecular weight of 516.94 kDa. SYQP@ZIF-8 exhibited high encapsulation rate (> 90 %), rapid pH-responsive release (within 60 min up to ~100 %), low toxicity and favorable hemolytic characteristics. Furthermore, it demonstrated reduced inflammatory cytokine secretion compared to SYQP, along with a superior inhibitory effect. The outcomes of in vivo experiments, including a decrease in the W/D ratio and LDH activity, further confirmed the efficacy of SYQP@ZIF-8 in treating LPS-induced ALI. In conclusion, SYQP@ZIF-8 released SYQP in acidic inflammatory conditions, outperforming SYQP alone in treating ALI.

Discovery of highly potent phosphodiesterase-1 inhibitors by a combined-structure free energy perturbation approach

Accurate receptor/ligand binding free energy calculations can greatly accelerate drug discovery by identifying highly potent ligands. By simulating the change from one compound structure to another, the relative binding free energy (RBFE) change can be calculated based on the theoretically rigorous free energy perturbation (FEP) method. However, existing FEP-RBFE approaches may face convergence challenges due to difficulties in simulating non-physical intermediate states, which can lead to increased computational costs to obtain the converged results. To fundamentally overcome these issues and accelerate drug discovery, a new combined-structure RBFE (CS-FEP) calculation strategy was proposed, which solved the existing issues by constructing a new alchemical pathway, smoothed the alchemical transformation, increased the phase-space overlap between adjacent states, and thus significantly increased the convergence and accelerated the relative binding free energy calculations. This method was extensively tested in a practical drug discovery effort by targeting phosphodiesterase-1 (PDE1). Starting from a PDE1 inhibitor (compound 9, IC50 = 16.8 μmol/L), the CS-FEP guided hit-to-lead optimizations resulted in a promising lead (11b and its mesylate salt formulation 11b-Mesylate, IC50 = 7.0 nmol/L), with ∼2400-fold improved inhibitory activity. Further experimental studies revealed that the lead showed reasonable metabolic stability and significant anti-fibrotic effects in vivo.

Modulating Fibrotic Mechanical Microenvironment for Idiopathic Pulmonary Fibrosis Therapy

Idiopathic pulmonary fibrosis (IPF) is exacerbated by injurious mechanical forces that destabilize the pulmonary mechanical microenvironment homeostasis, leading to alveolar dysfunction and exacerbating disease severity. However, given the inherent mechanosensitivity of fibrotic lungs, where type II alveolar epithelial cells (AEC IIs) are subjected to persistent stretching and overactivated myofibroblasts experience malignant interactions during mechanotransduction, it becomes imperative to develop effective strategies to modulate the pulmonary mechanical microenvironment. Herein, cyclo (RGDfC) peptide-decorated zeolitic imidazolate framework-8 nanoparticles (named ZDFPR NPs) are constructed to target and repair the aberrant mechanical force levels in pathological lungs. Specifically, reduces mechanical tension in AEC IIs by pH-responsive ZDFPR NPs that release zinc ions and 7, 8-dihydroxyflavone to promote alveolar repair and differentiation. Meanwhile, malignant interactions between myofibroblast contractility and extracellular matrix stiffness during mechanotransduction are disrupted by the fasudil inhibition ROCK signaling pathway. The results show that ZDFPR NPs successfully restored pulmonary mechanical homeostasis and terminated the fibrosis process in bleomycin-induced fibrotic mice. This study not only presents a promising strategy for modulating pulmonary mechanical microenvironment but also pioneers a novel avenue for IPF treatment.

Discovery of Selective PDE1 Inhibitors with Anti-pulmonary Fibrosis Effects by Targeting the Metal Pocket

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with no ideal drugs. Our previous research demonstrated that phosphodiesterase 1 (PDE1) could be a promising target for the treatment of IPF. However, only a few selective PDE1 inhibitors are available, and the mechanism of recognition between inhibitors and the PDE1 protein is not fully understood. This study carried out a step-by-step optimization of a dihydropyrimidine hit Z94555858. By targeting the metal pocket of PDE1, a lead compound 3f was obtained, exhibiting an IC50 value of 11 nM against PDE1, moderate selectivity over other PDEs, and significant anti-fibrotic effects in bleomycin-induced pulmonary fibrosis rats. The structure-activity relationship study aided by molecular docking revealed that forming halogen bonds with water in the metal pocket greatly enhanced the PDE1 inhibition, providing a novel strategy for further rational design of PDE1 inhibitors.

Insights into SARS-CoV-2: Small-Molecule Hybrids for COVID-19 Treatment

The advantages of a treatment modality that combines two or more therapeutic agents with different mechanisms of action encourage the study of hybrid functional compounds for pharmacological applications. Molecular hybridization, resulting from a covalent combination of two or more pharmacophore units, has emerged as a promising approach to overcome several issues and has also been explored for the design of new drugs for COVID-19 treatment. In this review, we presented an overview of small-molecule hybrids from both natural products and synthetic sources reported in the literature to date with potential antiviral anti-SARS-CoV-2 activity.

Mechanisms of mechanical stimulation in the development of respiratory system diseases

During respiration, mechanical stress can initiate biological responses that impact the respiratory system. Mechanical stress plays a crucial role in the development of the respiratory system. However, pathological mechanical stress can impact the onset and progression of respiratory diseases by influencing the extracellular matrix and cell transduction processes. In this article, we explore the mechanisms by which mechanical forces communicate with and influence cells. We outline the basic knowledge of respiratory mechanics, elucidating the important role of mechanical stimulation in influencing respiratory system development and differentiation from a microscopic perspective. We also explore the potential mechanisms of mechanical transduction in the pathogenesis and development of respiratory diseases such as asthma, lung injury, pulmonary fibrosis, and lung cancer. Finally, we look forward to new research directions in cellular mechanotransduction, aiming to provide fresh insights for future therapeutic research on respiratory diseases.

Liberation from extracorporeal membrane oxygenation in a patient with severe COVID-19-associated acute respiratory distress syndrome using traditional Chinese medicine: A case report

INTRODUCTION

Due to the continued threat to public health posed by SARS-CoV-2 and the ongoing emergence of novel variants, the integration of traditional Chinese medicine (TCM) with Western medicine provides a novel alternative management for critically ill patients.

CASE PRESENTATION

This case report describes a 54-year-old male with severe COVID-19-associated acute respiratory distress syndrome (ARDS) who required extracorporeal membrane oxygenation (ECMO) support. Despite standard treatment, ECMO liberation was unsuccessful, and complications such as pneumothorax and hemothorax ensued. However, upon initiating combined TCM therapy on the 19th day of ECMO support, the patient exhibited gradual improvements in oxygenation and ventilation, leading to successful ECMO liberation on the 31st day.

CONCLUSION

This case underscores the potential of integrating TCM with conventional therapies for severe COVID-19 cases, offering a valuable treatment option amidst the evolving landscape of SARS-CoV-2 variants.

Influenza, SARS-CoV-2, and Their Impact on Chronic Lung Diseases and Fibrosis: Exploring Therapeutic Options

Respiratory tract infections represent a significant global public health concern, disproportionately affecting vulnerable populations such as children, the elderly, and immunocompromised individuals. RNA viruses, particularly influenza viruses and coronaviruses, significantly contribute to respiratory illnesses, especially in immunosuppressed and elderly individuals. Influenza A viruses (IAVs) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to pose global health threats due to their capacity to cause annual epidemics, with profound implications for public health. In addition, the increase in global life expectancy is influencing the dynamics and outcomes of respiratory viral infections. Understanding the molecular mechanisms by which IAVs and SARS-CoV-2 contribute to lung disease progression is therefore crucial. The aim of this review is to comprehensively explore the impact of IAVs and SARS-CoV-2 on chronic lung diseases, with a specific focus on pulmonary fibrosis in the elderly. It also outlines potential preventive and therapeutic strategies and suggests directions for future research.

Tetrahedral Framework Nucleic Acids Delivery of Pirfenidone for Anti-Inflammatory and Antioxidative Effects to Treat Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible lung disease, and developing an effective treatment remains a challenge. The limited therapeutic options are primarily delivered by the oral route, among which pirfenidone (PFD) improves pulmonary dysfunction and patient quality of life. However, its high dose and severe side effects (dyspepsia and systemic photosensitivity) limit its clinical value. Intratracheal aerosolization is an excellent alternative method for treating lung diseases because it increases the concentration of the drug needed to reach the focal site. Tetrahedral framework nucleic acid (tFNA) is a drug delivery system with exceptional delivery capabilities. Therefore, we synthesized a PFD-tFNA (Pt) complex using tFNA as the delivery vehicle and achieved quantitative nebulized drug delivery to the lungs via micronebulizer for lung fibrosis treatment. In vivo, Pt exhibited excellent immunomodulatory capacity and antioxidant effects. Furthermore, Pt reduced mortality, gradually restored body weight and improved lung tissue structure. Similarly, Pt also exhibited superior fibrosis inhibition in an in vitro fibrosis model, as shown by the suppression of excessive fibroblast activation and epithelial-mesenchymal transition (EMT) in epithelial cells exposed to TGF-β1. Conclusively, Pt, a complex with tFNA as a transport system, could enrich the therapeutic regimen for IPF via intratracheal aerosolization inhalation.

Bioinformatics analysis based on extracted ingredients combined with network pharmacology, molecular docking and molecular dynamics simulation to explore the mechanism of Jinbei oral liquid in the therapy of idiopathic pulmonary fibrosis

Objective

Jinbei oral liquid (JBOL), which is derived from a traditional hospital preparation, is frequently utilized to treat idiopathic pulmonary fibrosis (IPF) and has shown efficacy in clinical therapy. However, there are now several obstacles facing the mechanism inquiry, including target proteins, active components, and the binding affinity between crucial compounds and target proteins. To gain additional insight into the mechanisms underlying JBOL in anti-IPF, this study used bioinformation technologies, including network pharmacology, molecular docking, and molecular dynamic simulation, with a substantial amount of data based on realistic constituents.

Methods

Using network pharmacology, we loaded 118 realistic compounds into the SwissTargetPrediction and SwissADME databases and screened the active compounds and target proteins. IPF-related targets were collected from the OMIM, DisGeNET, and GeneCards databases, and the network of IPF-active constituents was built with Cytoscape 3.10.1. The GO and KEGG pathway enrichment analyses were carried out using Metascape, and the protein-protein interaction (PPI) network was constructed to screen the key targets with the STRING database. Finally, the reciprocal affinity between the active molecules and the crucial targets was assessed through the use of molecular docking and molecular dynamics simulation.

Results

A total of 122 targets and 34 tested active compounds were summarized in this investigation. Among these, kaempferol, apigenin, baicalein were present in high degree. PPI networks topological analysis identified eight key target proteins. AGE-RAGE, EGFR, and PI3K-Akt signaling pathways were found to be regulated during the phases of cell senescence, inflammatory response, autophagy, and immunological response in anti-IPF of JBOL. It was verified by molecular docking and molecular dynamics simulation that the combining way and binding energy between active ingredients and selected targets.

Conclusions

This work forecasts the prospective core ingredients, targets, and signal pathways of JBOL in anti-IPF, which has confirmed the multiple targets and pathways of JBOL in anti-IPF and provided the first comprehensive assessment with bioinformatic approaches. With empirical backing and an innovative approach to the molecular mechanism, JBOL is being considered as a potential new medication.

Proteomics of severe SARS-COV-2 infection and paraquat poisoning in human lung tissue samples: comparison of microbial infected and toxic pulmonary fibrosis

Introduction

Pulmonary fibrosis (PF) encompasses a spectrum of lung conditions characterized by the abnormal accumulation of scar tissue in the lungs, leading to impaired respiratory function. Various conditions can result in severe PF, among which viral infections have emerged as significant triggers. In addition to viral infections, exposure to toxic substances such as paraquat represents another significant risk factor for PF. Therefore, this study aimed to explore the dissimilarities and similarities between PF triggered by viral infections and chemical toxicants, using the mechanism of PF in IPF as a reference.

Methods

Data-independent acquisition proteomics technology was employed to identify COVID-19 and paraquat-induced PF from the autopsy of lung tissue samples obtained from individuals who died due to PF. Bioinformatics was employed for differential protein analysis, and selected indicators were validated on pathological sections.

Results

Our results showed that the differential proteins associated with the two causes of PF were enriched in similar lung fibrosis-related signaling pathways, such as the Wnt signaling pathway. However, differences were observed in proteins such as CACYBP, we verified the consistency of the results with proteomics using the IHC approach.

Conclusion

This study illuminates distinct protein-level differences by investigating pulmonary fibrosis pathways in severe COVID-19 and paraquat poisoning. Although both conditions activate lung-protective and repair pathways, COVID-19 shows limited phosphorylation-independent ubiquitination of β-catenin compared to paraquat toxicity. These findings shed light on potential therapeutic targets for PF induced via diverse factors.