Emerging drug delivery strategies for idiopathic pulmonary fibrosis treatment

Development and characterization of AD-214, an anti-CXCR4 i-body-Fc fusion for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease characterized by scarring and tissue remodeling. Current treatments have limited efficacy and significant side effects. To address these limitations, we developed AD-214, an anti-CXCR4-Fc-fusion protein composed of an anti-CXCR4 i-body (AD-114) tethered at its C terminus to constant domains 2 and 3 of the Fc region of a mutated human IgG1 lacking effector function. AD-214 binds with high affinity and specificity to CXCR4, modulates intracellular signaling, and inhibits key fibrotic pathways. Using fibrosis models, we demonstrate that AD-214 treatment significantly reduces collagen deposition and lung remodeling and has a unique mode of action. In Phase 1 clinical trials, intravenous infusion of AD-214 led to high and sustained CXCR4 receptor occupancy (RO), but whether RO and efficacy are causally linked remained to be determined. Herein, we demonstrate that CXCR4 RO by AD-214 inhibits primary human leukocyte migration, a model fibrotic process, and that migration inhibition is achievable at concentrations of AD-214 present in the serum of healthy human volunteers administered AD-214. Taken together, these data provide proof of concept for AD-214 as a novel treatment strategy for IPF and suggest that clinically feasible dosing regimens may be efficacious.

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.

"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.

Formononetin-Loaded PLGA Large Porous Microparticles via Intratracheal Instillation for Bleomycin-Induced Pulmonary Fibrosis Treatment

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease of unknown cause, with few effective therapies available and high mortality rates. Our preceding research indicated that formononetin (FMN) could improve the symptoms of the bleomycin-induced pulmonary fibrosis and be a promising drug against IPF. In this study, an inhalable formononetin-loaded poly(lactic-co-glycolic) acid (PLGA) large porous microspheres (FMN-PLGA-MSs) was prepared by the method of emulsion solvent evaporation. SEM showed that FMN-PLGA-MSs were loose particles existing many pores on the surfaces, and the measured mean geometric diameter was more than 10 µm. The encapsulation efficiency (EE) and drug loading efficiency (DL) were 87.72 ± 6.34% and 4.18 ± 0.30%. FMN in FMN-PLGA-MSs could be rapidly released within 2 h and sustainably released for 21 d. Cell tests and q-RT-PCR tests showed that FMN could inhibit the activation of fibroblasts and the deposition of extracellular matrix (ECM) by acting on the TGF-β1/Smad3 signaling pathway. FMN-PLGA-MSs showed higher antifibrotic effects than free FMN oral administration in the pulmonary fibrosis models of mice, remarkably improving pulmonary function, decreasing hydroxyproline levels, and attenuating lung injuries. By formulating formononetin into microsphere preparations, its solubility can be significantly enhanced, enabling effective pulmonary drug delivery. This approach not only improves lung targeting but also reduces systemic toxicity. Additionally, it facilitates superior lung deposition and extends the retention time of the formononetin within the lungs. Taken together, FMN-PLGA-MSs may be a promising inhaled medication for the treatment of IPF.

Sustained Release of Antifibrotic Nintedanib from Polymer Microparticles Reduces Dosing Frequency While Reducing Inflammation in Murine Idiopathic Pulmonary Fibrosis

PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a life-threatening, progressive lung disease with limited therapeutic options, often resulting in poor patient outcomes. Current treatments, such as Nintedanib (NTB) and Pirfenidone (PFD), require frequent administration, leading to adverse effects and low patient adherence. The purpose of this study was to investigate a sustained-release drug delivery system utilizing microparticles (MPs) composed of insoluble beta-cyclodextrin (β-CD) polymers to enhance the bioavailability and extend the release of NTB and PFD.

METHODS

A multidisciplinary approach, including in silico modeling, in vitro assays, and in vivo studies, was employed to assess the efficacy of β-CD-polymer MPs as drug carriers.

RESULTS

Molecular docking simulations and surface plasmon resonance studies demonstrated a stronger binding affinity of NTB to β-CD-polymer MPs compared to PFD, suggesting an extended delivery profile for NTB over PFD. Pharmacokinetic analysis in healthy mice confirmed sustained-release profiles for both drugs, with NTB maintaining therapeutic plasma concentrations for over 70 h. In a bleomycin-induced IPF mouse model, NTB-loaded β-CD-polymer MPs significantly reduced pro-inflammatory markers and required fewer injections than the standard daily NTB regimen.

CONCLUSION

These findings indicate that β-CD-polymer MPs may serve as a promising platform for reducing dosing frequency of NTB and enhancing therapeutic outcomes in the treatment of IPF.

Enhanced delivery of azithromycin using asymmetric polyethersulfone membrane modified with KIT-6 mesoporous material: Optimization and mechanistic studies

This study presents the development of a novel drug delivery system designed for improving the release profile and sustained delivery of azithromycin (AZI), particularly aimed at applications requiring localized infection control and improved tissue compatibility. The system employs an asymmetric polyethersulfone (PES) membrane modified with KIT-6 mesoporous material, offering improved drug release performance and biocompatibility over conventional delivery platforms. Membrane optimization was achieved by systematically varying parameters such as thickness (150-600 µm), drug concentration (500-1500 mg/L), polymer content (13-21 % PES), pore maker percentage (0-4 % polyvinylpyrrolidone), and KIT-6 modifier percentage (0.5-2 %). Characterization included scanning electron microscopy, water contact angle measurements, porosity, tensile strength evaluation, and comprehensive bioactivity testing (cytotoxicity, antimicrobial efficacy, blood compatibility, and a novel tissue integrity assay). The optimized formulation (17 % PES, 2 % PVP, 1 % KIT-6) achieved a controlled and sustained release profile with improved drug availability (464 mg/L) compared to unmodified membranes (252 mg/L), with a sustained release profile governed by the Higuchi model. Additionally, the membrane demonstrated superior biocompatibility (-90 % cell viability, low hemolysis at 1.2 %) and preserved tissue integrity better than unmodified counterparts, as evidenced by in vitro and ex vivo studies. Notably, the system showed robust reusability over prolonged use, indicating its potential as an effective, sustainable, and biocompatible solution for localized AZI delivery. These advantages position this system as a promising alternative for medical applications requiring precise drug release and minimal tissue disruption.

Advancements in nanotechnology for targeted drug delivery in idiopathic pulmonary fibrosis: a focus on solid lipid nanoparticles and nanostructured lipid carriers

OBJECTIVE

This review aims to explore innovative therapeutic strategies, with a particular focus on recent advancements in drug delivery systems using bioinspired nanomaterials such as solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) for the idiopathic pulmonary fibrosis (IPF).

SIGNIFICANCE OF THE REVIEW

Current treatments for IPF, including the FDA-approved anti-fibrotic agents pirfenidone and nintedanib, primarily aim to slow disease progression rather than reverse fibrosis. Bioinspired nanomaterials like SLNs and NLCs have shown promise in enhancing the efficacy of anti-fibrotic agents by improving drug solubility, stability, and targeted delivery. These systems not only minimize systemic side effects but also maximize therapeutic impact in lung tissues, offering a new hope for improved patient management and outcomes in this debilitating disease.

KEY FINDINGS

SLNs facilitate sustained drug release and have demonstrated potential in delivering phosphodiesterase type 5 inhibitors effectively to lung cells. NLCs, on the other hand, exhibit superior biocompatibility and controlled release properties, making them suitable for pulmonary applications. Studies indicate that both SLNs and NLCs can enhance the bioavailability of drugs like ciprofloxacin and montelukast, thereby improving treatment outcomes in pulmonary conditions.

CONCLUSION

The integration of nanotechnology into anti-fibrotic therapy represents a significant advancement in addressing the challenges posed by IPF. By leveraging the unique properties of SLNs and NLCs, there is potential to overcome the limitations of current treatments and provide new therapeutic options that offer better management and improved outcomes for patients suffering from this debilitating disease.

Treatment of Bleomycin-induced Pulmonary Fibrosis by Intratracheal Instillation Administration of Ellagic Acid-Loaded Chitosan Nanoparticles

Idiopathic Pulmonary Fibrosis (IPF) is a rare and serious chronic interstitial lung disease that may endanger the lives of patients. The median survival time of patients with idiopathic pulmonary fibrosis is short, and the mortality rate is higher than that of many types of cancer. At present, pirfenidone (PFD) and nintedanib (NDNB) have been approved by FDA for IPF, but they can only delay the process of pulmonary fibrosis and cannot cure the disease. Therefore, it is urgent to develop other drugs with the effect of improving pulmonary fibrosis. Ellagic acid (EA) can inhibit the Wnt-signaling pathway and has an effect in treating pulmonary fibrosis induced by bleomycin (BLM) in mice. However, its solubility is poor, resulting in its low bioavailability and limited therapeutic benefits, so its clinical application has been limited. Herein, based on the characteristics of nano-drug lung delivery system, chitosan (CS) was selected as the carrier, and ellagic acid-loaded chitosan nanoparticles (EA-CS-NPs) were prepared by ionic gelation method. The EE% and DL% of prepared EA-CS-NPs was 73.73 ± 4.52% and 6.23 ± 1.09%, the particle size was 119.6 ± 5.51 nm (PDI = 0.234 ± 0.017), the zeta potential was 29.833 ± 0.503 mV. The morphology of the nanoparticles was observed by TEM microscope, which was round, uniform dispersion, indicating that the preparation process is stable and feasible. The toxicity experiment showed that EA-CS-NPs maintained 80% cell viability, significantly higher than that of the NDNB group, indicating lower toxicity and better inhibitory effects on TGF-β1-stimulated MLg and NIH-3T3 cells. Wound healing assay results showed that the inhibitory effect of EA-CS-NPs on cell migration was more pronounced than that of EA in the same amount of EA-containing drugs. Drug uptake experiments revealed that EA-CS-NPs significantly enhanced drug uptake in MLg and NIH-3T3 cells. In vivo, Cy7-CS-NPs exhibited higher fluorescence intensity in rat lungs compared to Cy7 solution, indicating better lung retention. The in vivo efficacy test showed that compared with the EA group, EA-CS-NPs could better reduce the area of pulmonary fibrosis and collagen deposition, improve lung function, and have a longer retention time in the lung. In summary, our results revealed that EA-CS-NPs may be a good choice for the treatment of pulmonary fibrosis.

Beyond the pill: incrimination of nuclear factor-kappa B and their targeted phytomedicine for pulmonary fibrosis

Pulmonary fibrosis (PF) is a slow and irreparable damage of the lung caused by the accumulation of scar tissue, which eventually results in organ dysfunction and fatality from gas exchange failure. One of the extensively studied inflammatory pathways in PF is the NF-κB signalling pathway, which is reportedly involved in epithelial-mesenchymal transition, myofibroblast differentiation, and other cellular processes. Additionally, studies have evidence that NF-κB signalling pathways can be employed as a potential target for developing therapeutic agents against PF. In the current scenario, FDA-approved drugs, nintedanib and pirfenidone, have been used for the treatment of PF with potential side effects. Recently, the usage of bioactive compounds has attracted attention in the treatment of PF. This review focuses on the involvement of the NF-κB signalling pathway in PF and the significance of phytocompounds in regulating the NF-κB pathway. Both the in vitro and in vivo studies reveal that NF-κB-targeted plant-based bioactive compounds significantly ameliorate the PF condition as well as improve the health condition. Databases such as Scopus, PubMed, and Web of Science were used to conduct literature surveys and compile data on all the bioactive compounds. In conclusion, the plant-derived bioactive compounds are potent enough to target the NF-κB with its biological properties, and this could be a highly effective therapeutic strategy for PF in the future.

In silico, in vitro, and in vivo assessment of chitosan-diltiazem nanoparticles against pulmonary fibrosis

AIMS

Diltiazem (DIL), a calcium channel blocker, has demonstrated potential ininhibiting fibrosis-related processes, including TGF-β activation, collagen production, and epithelial-mesenchymal transition, making it a promising candidate for idiopathic pulmonary fibrosis (IPF). This study evaluates the anti-fibrotic efficacy of DIL-loaded chitosan (DIL-CHT) and trimethyl chitosan (DIL-TMC) nanoparticles through molecular and experimental approaches.

METHODS

DIL-CHT and DIL-TMC nanoformulations were developed and analyzed particle size, ζ-potential, entrapment efficiency, and in vitro release. Antifibrotic efficacy in bleomycin (BLM)-induced IPF rat model, was tested at subtherapeutic doses (3 mg/kg/day, i.t.) and DIL alone (10 mg/kg/day, p.o.). DFT (B3LYP/6-31 G**) optimization and molecular docking were conducted to assess electronic properties and interactions among CHT, TMC, and DIL.

RESULTS

DIL-TMC and DIL-CHT nanoparticles were 175.6 nm and 267.8 nm, with entrapment efficiencies of 81.72% and 66.0%, respectively; TMC showed a superior 24-hour sustained release. TMC's larger HOMO-LUMO gap (ΔE = -0.260 eV vs. -0.253 eV for CHT) suggests greater stability, supporting its enhanced interaction with DIL. TMC nanoparticles significantly reduced BLM-induced IPF symptoms, i.e. BLM induced increased lung index, hydroxyproline accumulation, oxidative stress in lung tissue, and blood pressure.

CONCLUSIONS

These findings indicate the strong therapeutic potential of DIL-TMC for IPF with minimal cardiovascular side effects.

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.

Modulating NLRP3 Inflammasomes in Idiopathic Pulmonary Fibrosis: A Comprehensive Review on Flavonoid-Based Interventions

Idiopathic Pulmonary Fibrosis (IPF) is a severe, rapidly advancing disease that drastically diminishes life expectancy. Without treatment, it can progress to lung cancer. The precise etiology of IPF remains unknown, but inflammation and damage to the alveolar epithelium are widely thought to be pivotal in its development. Research has indicated that activating the NLRP3 inflammasome is a crucial mechanism in IPF pathogenesis, as it triggers the release of pro-inflammatory cytokines such as IL-1β, IL-18, and TGF-β. These cytokines contribute to the myofibroblast differentiation and extracellular matrix (ECM) accumulation. Currently, treatment options for IPF are limited. Only two FDA-approved medications, pirfenidone and nintedanib, are available. While these drugs can decelerate disease progression, they come with a range of side effects and do not cure the disease. Additional treatment strategies primarily involve supportive care and therapy. Emerging research has highlighted that numerous flavonoids derived from traditional medicines can inhibit the critical regulators responsible for activating the NLRP3 inflammasome. These flavonoids show promise as potential therapeutic agents for managing IPF, offering a new avenue for treatment that targets the core inflammatory processes of this debilitating condition.

The beneficial effects of Akkermansia muciniphila and its derivatives on pulmonary fibrosis

Pulmonary fibrosis (PF) is a progressive and debilitating respiratory condition characterized by excessive deposition of extracellular matrix proteins and scarring within the lung parenchyma. Despite extensive research, the pathogenesis of PF remains incompletely understood, and effective therapeutic options are limited. Emerging evidence suggests a potential link between gut microbiota dysbiosis and the development of PF, highlighting the gut-lung axis as a promising therapeutic target. Akkermansia muciniphila (A. muciniphila), a mucin-degrading bacterium residing in the gut mucosal layer, has garnered considerable interest due to its immunomodulatory and anti-inflammatory properties. This study investigates the therapeutic potential of live and pasteurized A. muciniphila, as well as its extracellular vesicles (EVs), in mitigating inflammation and fibrosis in a murine model of carbon tetrachloride (CCl4)-induced PF exacerbated by a high-fat diet (HFD). Male C57BL/6 mice were divided into groups receiving either a normal diet or an HFD, with or without CCl4 administration. The mice were then treated with live or pasteurized A. muciniphila, or its EVs. Lung tissue was analyzed for the expression of inflammatory markers and fibrosis markers using real-time PCR and ELISA. Administration of live and pasteurized A. muciniphila, as well as its EVs, significantly downregulated the expression of inflammatory and fibrosis markers in the lung tissue of CCl4-induced PF mice. Furthermore, these treatments ameliorated the increased production of IL-6 and reduced IL-10 levels observed in the HFD and CCl4-treated groups. These findings suggest that A. muciniphila and its derivatives exert protective effects against pulmonary inflammation and fibrosis, potentially through modulation of the gut-lung axis. The study highlights the therapeutic potential of A. muciniphila and its derivatives as novel interventions for the management of PF, warranting further preclinical and clinical investigations.

MiR-125b-5p alleviates pulmonary fibrosis by inhibiting TGFβ1-mediated epithelial-mesenchymal transition via targeting BAK1

This study explores the role and potential mechanisms of microRNA-125b-5p (miR-125b-5p) in pulmonary fibrosis (PF). PF is a typical outcome of many chronic lung diseases, with poor prognosis and the lack of appropriate medical treatment because PF's molecular mechanisms remain poorly understood. In this study, using in vitro and in vivo analyses, we find that miR-125b-5p is likely a potent regulator of lung fibrosis. The findings reveal that, on the one hand, miR-125b-5p not only specifically decreases in the epithelial-mesenchymal transition (EMT) of lung epithelial cells, but also shows a downregulation trend in the lung tissues of mice with PF. On the other hand, overexpression of miR-125b-5p on the cellular and animal levels downregulates EMT and fibrotic phenotypes, respectively. To clarify the molecular mechanism of the "therapeutic" effect of miR-125b-5p, we use the target prediction tool combined with a dual luciferase assay and complete a rescue experiment by constructing the overexpression vector of the target gene Bcl-2 homologous antagonist/ killer (BAK1), thus confirming that miR-125b-5p can effectively inhibit EMT and fibrosis process by targeting BAK1 gene. MiR-125b-5p inhibits the EMT in lung epithelial cells by negatively regulating BAK1, while overexpression of miR-125b-5p can alleviate lung fibrosis. The findings suggest that MiR-125b-5p/BAK1 can serve as a potential treatment target for PF.

Unravelling the toxicity of carbon nanomaterials - From cellular interactions to mechanistic understanding

The application of carbon nanomaterials in diverse fields has substantially increased their demand for commercial usage. Within the earliest decade, the development of functional materials has further increased the significance of this element. Despite the advancements recorded, the potential harmful impacts of embracing carbon nanomaterials for biological applications must be balanced against their advantages. Interestingly, many studies have neglected the intriguing and dynamic cellular interaction of carbon nanomaterials and the mechanistic understanding of their property-driven behaviour, even though common toxicity profiles have been reported. Reiterating the toxicity issue, several researchers conclude that these materials have minimal toxicity and may be safe for contact with biological systems at certain dosages. Here, we aim to provide a report on the significance of some of the properties that influence their toxicity. After that, a description of the implication of nanotoxicology in humans and living systems, revealing piece by piece their exposure routes and possible risks, will be provided. Then, an extensive discussion of the mechanistic puzzle modulating the interface between various human cellular systems and carbon nanomaterials such as carbon nanotubes, carbon dots, graphene, fullerenes, and nanodiamonds will follow. Finally, this review also sheds light on the organization that handles the risk associated with nanomaterials.

Navigating Drug-Induced Lung Disease (DILD): A Comprehensive Review on Management and Prevention Strategies

Drug-induced lung disease (DILD) is a significant and often overlooked adverse effect of pharmacological treatments, encompassing a range of pulmonary disorders triggered by medications. This review provides a comprehensive overview of DILD, focusing on its definition, pathophysiology, and clinical implications. We explore the epidemiology of DILD, highlighting the prevalence of various drugs associated with pulmonary toxicity and the factors influencing susceptibility. The review details the clinical presentation of DILD, including common symptoms and diagnostic challenges, and outlines diagnostic modalities such as imaging, pulmonary function tests, and invasive procedures. Management strategies are discussed, emphasizing the importance of timely drug discontinuation, supportive care, and the role of corticosteroids and novel therapies. Preventive measures, including pre-treatment evaluations and ongoing monitoring, are also addressed. The review concludes by examining future research directions and emerging therapies, aiming to enhance the understanding and management of DILD. This review is intended to aid healthcare professionals in recognizing, managing, and preventing drug-induced lung diseases, ultimately improving patient outcomes and safety.

Preparation and evaluation of inhalable S-allylmercapto-N-acetylcysteine and nintedanib co-loaded liposomes for pulmonary fibrosis

Orally marketed products nintedanib (NDNB) and pirfenidone (PFD) for pulmonary fibrosis (PF) are administered in high doses and have been shown to have serious toxic and side effects. NDNB can cause the elevation of galectin-3, which activates the NF-κB signaling pathway and causes the inflammatory response. S-allylmercapto-N-acetylcysteine (ASSNAC) can alleviate the inflammation response by inhibiting the TLR-4/NF-κB signaling pathway. Therefore, we designed and prepared inhalable ASSNAC and NDNB co-loaded liposomes for the treatment of pulmonary fibrosis. The yellow, spheroidal co-loaded liposomes with a particle size of 98.32±1.98 nm and zeta potential of -22.5 ± 1.58 mV were produced. The aerodynamic fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) of NDNB were >50 % (81.14 %±0.22 %) and <5 μm (1.79 μm±0.06 μm) in the nebulized liposome solution, respectively. The results showed that inhalation improved the lung deposition and retention times of both drugs. DSPE-PEG 2000 in the liposome formulation enhanced the mucus permeability and reduced phagocytic efflux mediated by macrophages. ASSNAC reduced the mRNA over-expressions of TLR-4, MyD88 and NF-κB caused by NDNB, which could reduce the NDNB's side effects. The Masson's trichrome staining of lung tissues and the levels of CAT, TGF-β1, HYP, collagen III and mRNA expressions of Collagen I, Collagen III and α-SMA in lung tissues revealed that NDNB/Lip inhalation was more beneficial to alleviate fibrosis than oral NDNB. Although the dose of NDNB/Lip was 30 times lower than that in the oral group, the inhaled NDNB/Lip group had better or comparable anti-fibrotic effects to those in the oral group. According to the expressions of Collagen I, Collagen III and α-SMA in vivo and in vitro, the combination of ASSNAC and NDNB was more effective than the single drugs for pulmonary fibrosis. Therefore, this study provided a new scheme for the treatment of pulmonary fibrosis.

Mendelian randomization study on the causal effect of herpes simplex virus infection on idiopathic pulmonary fibrosis

BACKGROUND

Previous observational studies have shown that past infection of herpes simplex virus (HSV) is associated with idiopathic pulmonary fibrosis (IPF). The present study aims to identify the causal link between HSV infection (exposure factor) and IPF (outcome factor).

RESEARCH DESIGN AND METHODS

To date, the largest publicly available genome-wide association study (GWAS) for HSV infection (1,595 cases and 211,856 controls from Finnish ancestry) and for IPF (1,028 cases and 196,986 controls from Finnish ancestry) were used to perform this two-sample Mendelian randomization (MR) study.

RESULTS

We found no significant pleiotropy or heterogeneity of all selected nine HSV infection-associated genetic instrumental variants (IVs) in IPF GWAS dataset. Interestingly, we found that as HSV infection genetically increased, IPF risk increased based on an inverse-variance weighted (IVW) analysis (odds ratio [OR] = 1.280, 95% confidence interval [CI]: 1.048-1.563; p = 0.015) and weighted median (OR = 1.321, 95% CI: 1.032-1.692; p = 0.027).

CONCLUSIONS

Our analysis suggests a causal effect of genetically increased HSV infection on IPF risk. Thus, HSV infection may be a potential risk factor for IPF.

A prognostic model of idiopathic pulmonary fibrosis constructed based on macrophage and mitochondria-related genes

BACKGROUND

Studies have shown that mitochondrial function and macrophages may play a role in the development of idiopathic pulmonary fibrosis (IPF). However, the understanding of the interactions and specific mechanisms between mitochondrial function and macrophages in pulmonary fibrosis is still very limited.

METHODS

To construct a prognostic model for IPF based on Macrophage- related genes (MaRGs) and Mitochondria-related genes (MitoRGs), differential analysis was performed to achieve differentially expressed genes (DEGs) between IPF and Control groups in the GSE28042 dataset. Then, MitoRGs, MaRGs and DEGs were overlapped to screen out the signature genes. The univariate Cox analysis and the least absolute shrinkage and selection operator (LASSO) algorithm were implemented to achieve key genes. Furthermore, the independent prognostic analysis was employed. The ingenuity pathway analysis (IPA) was employed to further understand the molecular mechanisms of key genes.Next, the immune infiltration analysis was implemented to identify differential immune cells between two risk subgroups.

RESULTS

There were 4791 DEGs between IPF and Control groups. Furthermore, 26 signature genes were achieved by the intersection processing. Three key genes including ALDH2, MCL1, and BCL2A1 were achieved, and the risk model based on the key genes was created. In addition, a nomogram for survival forecasting of IPF patients was created based on riskScore, Age, and Gender, and we found that key genes were associated with classical pathways including 'Apoptosis Signaling', 'PI3K/AKT Signaling', and so on. Next, two differential immune cells including Monocytes and CD8 T cells were identified between two risk subgroups. Moreover, we found that MIR29B2CHG and hsa-mir-1-3p could regulate the expression of ALDH2.

CONCLUSION

We achieved 3 key genes including ALDH2, MCL1,, and BCL2A1 associated with IPF, providing a new theoretical basis for clinical treatment of IPF.

Revolutionizing the Treatment of Idiopathic Pulmonary Fibrosis: From Conventional Therapies to Advanced Drug Delivery Systems

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease that has been well-reported in the medical literature. Its incidence has risen, particularly in light of the recent COVID-19 pandemic. Conventionally, IPF is treated with antifibrotic drugs-pirfenidone and nintedanib-along with other drugs for symptomatic treatments, including corticosteroids, immunosuppressants, and bronchodilators based on individual requirements. Several drugs and biologicals such as fluorofenidone, thymoquinone, amikacin, paclitaxel nifuroxazide, STAT3, and siRNA have recently been evaluated for IPF treatment that reduces collagen formation and cell proliferation in the lung. There has been a great deal of research into various treatment options for pulmonary fibrosis using advanced delivery systems such as liposomal-based nanocarriers, chitosan nanoparticles, PLGA nanoparticles, solid lipid nanocarriers, and other nanoformulations such as metal nanoparticles, nanocrystals, cubosomes, magnetic nanospheres, and polymeric micelles. Several clinical trials are also ongoing for advanced IPF treatments. This article elaborates on the pathophysiology of IPF, its risk factors, and different advanced drug delivery systems for treating IPF. Although extensive preclinical data is available for these delivery systems, the clinical performance and scale-up studies would decide their commercial translation.

Designing inhaled small molecule drugs for severe respiratory diseases: an overview of the challenges and opportunities

INTRODUCTION

Inhaled drugs offer advantages for the treatment of respiratory diseases over oral drugs by delivering the drug directly to the lung, thus improving the therapeutic index. There is an unmet medical need for novel therapies for lung diseases, exacerbated by a multitude of challenges for the design of inhaled small molecule drugs.

AREAS COVERED

The authors review the challenges and opportunities for the design of inhaled drugs for respiratory diseases with a focus on new target discovery, medicinal chemistry, and pharmacokinetic, pharmacodynamic, and toxicological evaluation of drug candidates.

EXPERT OPINION

Inhaled drug discovery is facing multiple unique challenges. Novel biological targets are scarce, as is the guidance for medicinal chemistry teams to design compounds with inhalation-compatible features. It is exceedingly difficult to establish a PK/PD relationship given the complexity of pulmonary PK and the impact of physical properties of the drug substance on PK. PK, PD and toxicology studies are technically challenging and require large amounts of drug substance. Despite the current challenges, the authors foresee that the design of inhaled drugs will be facilitated in the future by our increasing understanding of pathobiology, emerging medicinal chemistry guidelines, advances in drug formulation, PBPK models, and in vitro toxicology assays.

Epithelial IL5RA promotes epithelial-mesenchymal transition in pulmonary fibrosis via Jak2/STAT3 cascade

Pulmonary fibrosis is a progressive and debilitating lung disease characterized by the excessive accumulation of extracellular matrix (ECM) components within the lung parenchyma. However, the underlying mechanism remains largely elusive, and the treatment options available for pulmonary fibrosis are limited. Interleukin 5 receptor, alpha (IL5RA) is a well-established regulator of eosinophil activation, involved in eosinophil-mediated anti-parasitic activities and allergic reactions. Recent studies have indicated additional roles of IL5RA in lung epithelium and fibroblasts. Nevertheless, its involvement in pulmonary fibrosis remains unclear. In present study, we employed single-cell analyses alongside molecular and cellular assays to unveil the expression of IL5RA in lung epithelial cells. Moreover, using both in vitro and in vivo models, we demonstrated a notable upregulation of epithelial IL5RA during the progression of pulmonary fibrosis. This upregulated IL5RA expression subsequently promotes epithelial-mesenchymal transition (EMT), leading to the generation of mesenchymal phenotype with augmented capability for ECM production. Importantly, our findings uncovered that the pro-fibrotic function of IL5RA is mediated by Jak2/STAT3 signaling cascades. Inhibiting IL5RA has the potential to deactivate Jak2/STAT3 and suppress the downstream EMT process and ECM production, thereby offering a promising therapeutic strategy for pulmonary fibrosis.

Mefloquine improves pulmonary fibrosis by inhibiting the KCNH2/Jak2/Stat3 signaling pathway in macrophages

Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease characterized by severe pulmonary fibrosis, for which there is an urgent need for effective therapeutic agents. Mefloquine (Mef) is a quinoline compound primarily used for the treatment of malaria. However, high doses (>25 mg/kg) may lead to side effects such as cardiotoxicity and psychiatric disorders. Here, we found that low-dose Mef (5 mg/kg) can safely and effectively treat IPF mice. Functionally, Mef can improve the pulmonary function of IPF mice (PIF, PEF, EF50, VT, MV, PENH), alleviating pulmonary inflammation and fibrosis by inhibiting macrophage activity. Mechanically, Mef probably regulates the Jak2/Stat3 signaling pathway by binding to the 492HIS site of Potassium voltage-gated channel subfamily H member 2 (KCNH2) protein in macrophages, inhibiting the secretion of macrophage inflammatory and fibrotic factors. In summary, Mef may inhibit macrophage activity by binding to KCNH2 protein, thereby slowing down the progress of IPF.

Pulmonary fibrosis: Emerging diagnostic and therapeutic strategies

Fibrosis is the concluding pathological outcome and major cause of morbidity and mortality in a number of common chronic inflammatory, immune-mediated and metabolic diseases. The progressive deposition of a collagen-rich extracellular matrix (ECM) represents the cornerstone of the fibrotic response and culminates in organ failure and premature death. Idiopathic pulmonary fibrosis (IPF) represents the most rapidly progressive and lethal of all fibrotic diseases with a dismal median survival of 3.5 years from diagnosis. Although the approval of the antifibrotic agents, pirfenidone and nintedanib, for the treatment of IPF signalled a watershed moment for the development of anti-fibrotic therapeutics, these agents slow but do not halt disease progression or improve quality of life. There therefore remains a pressing need for the development of effective therapeutic strategies. In this article, we review emerging therapeutic strategies for IPF as well as the pre-clinical and translational approaches that will underpin a greater understanding of the key pathomechanisms involved in order to transform the way we diagnose and treat pulmonary fibrosis.

Pulmonary Fibrosis: Unveiling the Pathogenesis, Exploring Therapeutic Targets, and Advancements in Drug Delivery Strategies

Idiopathic pulmonary fibrosis (IPF) is an ailment with no cure and a very high rate of progression that ultimately leads to death. The exact reason for this disease is still not acknowledged. Many underlying mechanisms of wound healing and various types of stimuli that trigger the pathogenesis of IPF continue to be intensively explored. The exact therapy for the reversal of this disease is not yet known and is constantly in progress. Existing treatments only slow down the process or mitigate the symptoms to enhance the patient's healthcare system. The only two Food and Drug Administration-approved oral medications include pirfenidone and nintedanib whose high dose and systemic circulation can have side effects to a greater extent. Further research on restorative and extra-curative therapies for IPF is necessary due to the absence of viable therapeutic choices. To assure minimum off-targeted site delivery and longer duration of action, techniques that offer a sustainable release of the drug, better bioavailability, and patient compliance can be used.The work is an overview of the main therapeutic targets and pertinent developing therapies for the management of IPF. This study is an attempt to focus on various drug delivery systems that are responsible for showing effectiveness in defense mechanisms against IPF.

Inhaled nano-based therapeutics for pulmonary fibrosis: recent advances and future prospects

It is reported that pulmonary fibrosis has become one of the major long-term complications of COVID-19, even in asymptomatic individuals. Currently, despite the best efforts of the global medical community, there are no treatments for COVID-induced pulmonary fibrosis. Recently, inhalable nanocarriers have received more attention due to their ability to improve the solubility of insoluble drugs, penetrate biological barriers of the lungs and target fibrotic tissues in the lungs. The inhalation route has many advantages as a non-invasive method of administration and the local delivery of anti-fibrosis agents to fibrotic tissues like direct to the lesion from the respiratory system, high delivery efficiency, low systemic toxicity, low therapeutic dose and more stable dosage forms. In addition, the lung has low biometabolic enzyme activity and no hepatic first-pass effect, so the drug is rapidly absorbed after pulmonary administration, which can significantly improve the bioavailability of the drug. This paper summary the pathogenesis and current treatment of pulmonary fibrosis and reviews various inhalable systems for drug delivery in the treatment of pulmonary fibrosis, including lipid-based nanocarriers, nanovesicles, polymeric nanocarriers, protein nanocarriers, nanosuspensions, nanoparticles, gold nanoparticles and hydrogel, which provides a theoretical basis for finding new strategies for the treatment of pulmonary fibrosis and clinical rational drug use.

A fibroblastic foci-targeting and hypoxia-cleavable delivery system of pirfenidone for the treatment of idiopathic pulmonary fibrosis

The progressive formation of fibroblastic foci characterizes idiopathic pulmonary fibrosis (IPF), and excessive oral doses of approved pirfenidone (PFD) always cause gastrointestinal side effects. The fibrotic response driven by activated fibroblasts could perpetuate epithelial damage and promote abnormal extracellular matrix (ECM) deposition. When modified nanoparticles reach their target, it is important to ensure a responsive release of PFD. Hypoxia is a determining factor in IPF, leading to alveolar dysfunction and deeper cellular fibrosis. Herein, a fibroblastic foci-targeting and hypoxia-cleavable drug delivery system (Fn-Azo-BSA@PEG) was established to reprogram the fibrosis in IPF. We have modified the FnBAP5 peptide to enable comprehensive fibroblastic foci targeting, which helps BSA nanoparticles recognize and accumulate at fibrotic sites. Meantime, the hypoxia-responsive azobenzene group allowed for efficient and rapid drug diffusion, while the PEGylated BSA reduced system toxicity and increased circulation in vivo. As expected, the strategy of the fibronectin-targeting-modification and hypoxia-responsive drug release synergistically inhibited activated fibroblasts and reduced the secretion of the fibrosis-related protein. Fn-Azo-BSA@PEG could accumulate in pulmonary tissue and prolong the survival time in bleomycin-induced pulmonary fibrosis mice. Together, the multivalent BSA nanoparticles offered an efficient approach for improving lung architecture and function by regulating the fibroblastic foci and hypoxia. STATEMENT OF SIGNIFICANCE: We established fibroblastic foci-targeting and hypoxia-cleavable bovine serum albumin (BSA) nanoparticles (Fn-Azo-BSA@PEG) to reprogramme the fibroblastic foci in idiopathic pulmonary fibrosis (IPF). Fn-Azo-BSA@PEG was designed to actively target fibroblasts and abnormal ECM with the FnBPA5 peptide, delivering more FDA-approved pirfenidone (PFD) to the cross-talk within the foci. Once the drug reached fibroblastic foci, the azobenzene group acted as a hypoxia-responsive linker to trigger effective and rapid drug release. Hypoxic responsiveness and FnBAP5-modification of Fn-Azo-BSA@PEG synergistically inhibited the secretion of proteins closely related to fibrogenesis. BSA's inherent transport and metabolic pathways in the pulmonary reduced the side effects of the main organs. The multivalent BSA nanoparticles efficiently inhibited IPF-fibrosis progress and preserved the lung architecture by regulating the fibroblastic foci and hypoxia.

Sparganii Rhizoma alleviates pulmonary fibrosis by inhibiting fibroblasts differentiation and epithelial-mesenchymal transition mediated by TGF-β1/ Smad2/3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Pulmonary fibrosis (PF), a lethal lung disease, can lead to structural destruction of the alveoli until death. Sparganii Rhizoma (SR), primarily distributed in East Asia, has been used clinically for hundreds of years against organ fibrosis and inflammation.

AIM OF THE STUDY

We intended to verify the effect of SR alleviate PF and further explore mechanisms.

METHODS

Murine model of PF was established by endotracheal infusion of bleomycin. We detected the anti-PF effect of SR through lung coefficient, hydroxyproline content, lung function and pathological staining. Then, we used Western Blot and RT-PCR to verify the mechanism. In vitro experiments, MRC-5 and BEAS-2B were induced to phenotypic transformation by TGF-β1 and then RT-PCR, WB and IF were conducted to verify the effect of SR.

RESULTS

SR significantly reduced BLM-induced PF in mice, improved lung function, slowed the degree of lung tissue lesions, and reduced collagen deposition. SR alleviated PF by inhibiting fibroblasts differentiation and epithelial-mesenchymal transition. In vivo studies explored the mechanism and found that it was related to TGF-β1/Smad2/3 pathway.

CONCLUSIONS

Our research proved SR could effectively treat PF, providing a fresh idea and approach for the treatment of PF with traditional Chinese medicine.

Magnetic liposome as a dual-targeting delivery system for idiopathic pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) is the most common form of idiopathic interstitial pneumonia, where M2 macrophages play an irreplaceable role in the anti-inflammatory progress. Targeting M2 macrophages and regulating their polarization may be a potential treatment strategy for IPF. Herein, we designed a magnetic liposome based dual-targeting delivery system for the IPF treatment, constructed by mannose-modified magnetic nanoparticles (MAN-MNPs) loaded on the surface of the liposome (MAN-MNPs@LP). The delivery system is capable of responding to a static magnetic field (SMF) and then recognizing in situ of M2 macrophages through the mannose receptor-dependent internalization. Firstly, a series of physical and chemical assays were used to characterize these nanoparticles. Subsequently, magnetic liposomes accumulation in the damaged lung with/without mannose modification and SMF were compared by in vivo imaging system. Finally, the reduction of M2 macrophages and inhibition of their polarization confirmed that the development of IPF was retarded due to the in situ release of encapsulated dexamethasone (Dex) in lungs under the SMF. Further investigation demonstrated that the expression of α-SMA and collagen deposition was reduced. Altogether, this dual-targeting delivery system can effectively deliver Dex into M2 macrophages in the lung, making it a novel and promising therapeutic system for the IPF treatment.

Inhaled Lipid Nanoparticles Alleviate Established Pulmonary Fibrosis

Pulmonary fibrosis, a sequela of lung injury resulting from severe infection such as severe acute respiratory syndrome-like coronavirus (SARS-CoV-2) infection, is a kind of life-threatening lung disease with limited therapeutic options. Herein, inhalable liposomes encapsulating metformin, a first-line antidiabetic drug that has been reported to effectively reverse pulmonary fibrosis by modulating multiple metabolic pathways, and nintedanib, a well-known antifibrotic drug that has been widely used in the clinic, are developed for pulmonary fibrosis treatment. The composition of liposomes made of neutral, cationic or anionic lipids, and poly(ethylene glycol) (PEG) is optimized by evaluating their retention in the lung after inhalation. Neutral liposomes with suitable PEG shielding are found to be ideal delivery carriers for metformin and nintedanib with significantly prolonged retention in the lung. Moreover, repeated noninvasive aerosol inhalation delivery of metformin and nintedanib loaded liposomes can effectively diminish the development of fibrosis and improve pulmonary function in bleomycin-induced pulmonary fibrosis by promoting myofibroblast deactivation and apoptosis, inhibiting transforming growth factor 1 (TGFβ1) action, suppressing collagen formation, and inducing lipogenic differentiation. Therefore, this work presents a versatile platform with promising clinical translation potential for the noninvasive inhalation delivery of drugs for respiratory disease treatment.

Enhancement of suppression oxidative stress and inflammation of quercetin by nano-decoration for ameliorating silica-induced pulmonary fibrosis

Silicosis is a life-threatening lung fibrotic disease caused by excessive inhalation of environmental exposure to crystalline silica-containing dust, whereas achieving therapeutic cures are constrained. Antioxidation and anti-inflammation are currently recognized as effective strategies to counteract organ fibrosis. Using naturally occurring phytomedicines quercetin (Qu) has emerged in antagonizing fibrotic disorders involving oxidative stress and inflammation, but unfortunately the hydrophilicity deficiency. Herein, chitosan-assisted encapsulation of Qu in nanoparticles (Qu/CS-NPs) was first fabricated for silicosis-associated fibrosis treatment by pulmonary delivery. Qu/CS-NPs with spherical diameters of ~160 nm, demonstrated a high Qu encapsulated capability, excellent hydrophilic stability, fantastic oxidation radical scavenging action, and outstanding controlled as well as slow release Qu action. A silicosis rat model induced by intratracheal instillation silica was established to estimate the anti-fibrosis effect of Qu/CS-NPs. After intratracheal administration, CS-NPs markedly enhanced Qu anti-fibrotic therapy efficacy, accompanying the evident changes in reducing ROS and MDA production to mitigate oxidative stress, inhibiting IL-1β and TNF-α release, improving lung histological architecture, down-regulating α-SAM levels and suppressing ECM deposition, and thereby ameliorating silica-induced pulmonary fibrosis. Results manifested that the augmented antioxidant and anti-inflammatory activities of Qu by CS-NPs delivery was a result of achieving this remarkable improvement in curative effects. Combined with negligible systemic toxicity, nano-decorated Qu may provide a feasible therapeutic option for silicosis therapy.

Arctiin-encapsulated DSPE-PEG bubble-like nanoparticles inhibit alveolar epithelial type 2 cell senescence to alleviate pulmonary fibrosis via the p38/p53/p21 pathway

Background: Idiopathic pulmonary fibrosis is a severe and deadly form of diffuse parenchymal lung disease and treatment options are few. Alveolar epithelial type 2 (AEC2) cell senescence is implicated in the pathogenies of IPF. A major bioactive compound from the traditional Chinese medicine Fructus arctii, arctiin (ARC) has robust anti-inflammatory, anti-senescence, and anti-fibrosis functions. However, the potential therapeutic effects of ARC on IPF and the underlying mechanisms involved are still unknown.

Methods: First of all, ARC was identified as an active ingredient by network pharmacology analysis and enrichment analysis of F. arctii in treating IPF. We developed ARC-encapsulated DSPE-PEG bubble-like nanoparticles (ARC@DPBNPs) to increase ARC hydrophilicity and achieve high pulmonary delivery efficiency. C57BL/6 mice were used to establish a bleomycin (BLM)-induced pulmonary fibrosis model for assessing the treatment effect of ARC@DPBNPs on lung fibrosis and the anti-senescence properties of AEC2. Meanwhile, p38/p53 signaling in AEC2 was detected in IPF lungs, BLM-induced mice, and an A549 senescence model. The effects of ARC@DPBNPs on p38/p53/p21 were assessed in vivo and in vitro.

Results: Pulmonary route of administration of ARC@DPBNPs protected mice against BLM-induced pulmonary fibrosis without causing significant damage to the heart, liver, spleen, or kidney. ARC@DPBNPs blocked BLM-induced AEC2 senescence in vivo and in vitro. The p38/p53/p21 signaling axis was significantly activated in the lung tissues of patients with IPF, senescent AEC2, and BLM-induced lung fibrosis. ARC@DPBNPs attenuated AEC2 senescence and pulmonary fibrosis by inhibiting the p38/p53/p21 pathway.

Conclusion: Our data suggest that the p38/p53/p21 signaling axis plays a pivotal role in AEC2 senescence in pulmonary fibrosis. The p38/p53/p21 signaling axis inhibition by ARC@DPBNPs provides an innovative approach to treating pulmonary fibrosis in clinical settings.

An evolving perspective on novel modified release drug delivery systems for inhalational therapy

INTRODUCTION

Drugs delivered via the lungs are predominantly used to treat various respiratory disorders, including asthma, chronic obstructive pulmonary diseases, respiratory tract infections and lung cancers, and pulmonary vascular diseases such as pulmonary hypertension. To treat respiratory diseases, targeted, modified or controlled release inhalation formulations are desirable for improved patient compliance and superior therapeutic outcome.

AREAS COVERED

This review summarizes the important factors that have an impact on the inhalable modified release formulation approaches with a focus toward various formulation strategies, including dissolution rate-controlled systems, drug complexes, site-specific delivery, drug-polymer conjugates, and drug-polymer matrix systems, lipid matrix particles, nanosystems, and formulations that can bypass clearance via mucociliary system and alveolar macrophages.

EXPERT OPINION

Inhaled modified release formulations can potentially reduce dosing frequency by extending drug's residence time in the lungs. However, inhalable modified or controlled release drug delivery systems remain unexplored and underdeveloped from the commercialization perspective. This review paper addresses the current state-of-the-art of inhaled controlled release formulations, elaborates on the avenues for developing newer technologies for formulating various drugs with tailored release profiles after inhalational delivery and explains the challenges associated with translational feasibility of modified release inhalable formulations.

Phosphodiesterase 4B inhibition: a potential novel strategy for treating pulmonary fibrosis

Patients with interstitial lung disease can develop a progressive fibrosing phenotype characterised by an irreversible, progressive decline in lung function despite treatment. Current therapies slow, but do not reverse or stop, disease progression and are associated with side-effects that can cause treatment delay or discontinuation. Most crucially, mortality remains high. There is an unmet need for more efficacious and better-tolerated and -targeted treatments for pulmonary fibrosis. Pan-phosphodiesterase 4 (PDE4) inhibitors have been investigated in respiratory conditions. However, the use of oral inhibitors can be complicated due to class-related systemic adverse events, including diarrhoea and headaches. The PDE4B subtype, which has an important role in inflammation and fibrosis, has been identified in the lungs. Preferentially targeting PDE4B has the potential to drive anti-inflammatory and antifibrotic effects via a subsequent increase in cAMP, but with improved tolerability. Phase I and II trials of a novel PDE4B inhibitor in patients with idiopathic pulmonary fibrosis have shown promising results, stabilising pulmonary function measured by change in forced vital capacity from baseline, while maintaining an acceptable safety profile. Further research into the efficacy and safety of PDE4B inhibitors in larger patient populations and for a longer treatment period is needed.

Novel drug delivery systems and disease models for pulmonary fibrosis

Pulmonary fibrosis (PF) is a serious and progressive lung disease which is possibly life-threatening. It causes lung scarring and affects lung functions including epithelial cell injury, massive recruitment of immune cells and abnormal accumulation of extracellular matrix (ECM). There is currently no cure for PF. Treatment for PF is aimed at slowing the course of the disease and relieving symptoms. Pirfenidone (PFD) and nintedanib (NDNB) are currently the only two FDA-approved oral medicines to slow down the progress of idiopathic pulmonary fibrosis, a specific type of PF. Novel drug delivery systems and therapies have been developed to improve the prognosis of the disease, as well as reduce or minimize the toxicities during drug treatment. The drug delivery routes for these therapies are various including oral, intravenous, nasal, inhalant, intratracheal and transdermal; although this is dependent on specific treatment mechanisms. In addition, researchers have also expanded current animal models that could not fully restore the clinicopathology, and developed a series of in vitro models such as organoids to study the pathogenesis and treatment of PF. This review describes recent advances on pathogenesis exploration, classifies and specifies the progress of drug delivery systems by their delivery routes, as well as an overview on the in vitro and in vivo models for PF research.

The Antifibrotic Effects of Inhaled Treprostinil: An Emerging Option for ILD

Interstitial lung diseases (ILD) encompasses a heterogeneous group of parenchymal lung diseases characterized by variable amounts of inflammation and fibrosis. The targeting of fibroblasts and myofibroblasts with antifibrotic treatments is a potential therapeutic target for these potentially fatal diseases. Treprostinil is unique among the prostacyclin mimetics in that it has distinct actions at additional prostaglandin receptors. Preclinical and clinical evidence suggests that treprostinil has antifibrotic effects through the activation of the prostaglandin E receptor 2 (EP₂), the prostaglandin D receptor 1 (DP₁), and peroxisome proliferator-activated receptors (PPAR). In vivo studies of EP₂ and the DP₁ have found that administration of treprostinil resulted in a reduction in cell proliferation, reduced collagen secretion and synthesis, and reduced lung inflammation and fibrosis. In vitro and in vivo studies of PPARβ and PPARγ demonstrated that treprostinil inhibited fibroblast proliferation in a dose-dependent manner. Clinical data from a post hoc analysis of the INCREASE trial found that inhaled treprostinil improved forced vital capacity in the overall population as well as in idiopathic interstitial pneumonia and idiopathic pulmonary fibrosis subgroups. These preclinical and clinical findings suggest a dual benefit of treprostinil through the amelioration of both lung fibrosis and pulmonary hypertension.

Advances in the design of new types of inhaled medicines

Inhalation of small molecule drugs has proven very efficacious for the treatment of respiratory diseases due to enhanced efficacy and a favourable therapeutic index compared with other dosing routes. It enables targeted delivery to the lung with rapid onset of therapeutic action, low systemic drug exposure, and thereby reduced systemic side effects. An increasing number of pharmaceutical companies and biotechs are investing in new modalities-for this review defined as therapeutic molecules with a molecular weight >800Da and therefore beyond usual inhaled small molecule drug-like space. However, our experience with inhaled administration of PROTACs, peptides, oligonucleotides (antisense oligonucleotides, siRNAs, miRs and antagomirs), diverse protein scaffolds, antibodies and antibody fragments is still limited. Investigating the retention and metabolism of these types of molecules in lung tissue and fluid will contribute to understanding which are best suited for inhalation. Nonetheless, the first such therapeutic molecules have already reached the clinic. This review will provide information on the physiology of healthy and diseased lungs and their capacity for drug metabolism. It will outline the stability, aggregation and immunogenicity aspects of new modalities, as well as recap on formulation and delivery aspects. It concludes by summarising clinical trial outcomes with inhaled new modalities based on information available at the end of 2021.

Engineering of Stimulus-Responsive Pirfenidone Liposomes for Pulmonary Delivery During Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterized by progressive and irreversible loss of lung function. Clinically safe and efficacious drug treatments for IPF are lacking. Pirfenidone (an anti-inflammatory, antioxidant and anti-fibrotic small-molecule drug) is considered a promising treatment for IPF. Unfortunately, several disadvantages of pirfenidone caused by traditional administration (e.g., gastrointestinal reactions, short elimination half-life) hinder its implementation. We designed pirfenidone pH-sensitive liposomes (PSLs) to target the acidic microenvironment of IPF and act directly at the disease site through pulmonary administration. Pirfenidone was encapsulated in liposomes to extend its half-life, and modified with polyethylene glycol on the surface of liposomes to improve the permeability of the mucus layer in airways. In vitro, the cytotoxicity of pirfenidone PSLs to pulmonary fibroblasts was increased significantly at 48 h compared with that using pirfenidone. In a murine and rat model of bleomycin-induced pulmonary fibrosis, pirfenidone PSLs inhibited IPF development and increased PSL accumulation in the lungs compared with that using pirfenidone solution or phosphate-buffered saline. Pirfenidone PSLs had potentially fewer side effects and stronger lung targeting. These results suggest that pirfenidone PSLs are promising preparations for IPF treatment.

Efficacy of Qingfei oral liquid for idiopathic pulmonary fibrosis in rats and related network pharmacology study

To investigate the therapeutic effect and mechanism of Qingfei oral liquid in idiopathic pulmonary fibrosis. Seventy-two male SD rats were divided into control group, model group, pirofenidone group and Qingfei group with 18 animals in each group. The idiopathic pulmonary fibrosis was induced in last three groups by intratracheal injection of bleomycin; pirofenidone group was given oral administration of pirofenidone b.i.d for 21 d, and Qingfei group was given Qingfei oral liquid 3.6 mL/kg q.d for Lung tissues were obtained for HE staining, Masson staining and transforming growth factor (TGF)-β immunohistochemical staining. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were detected in tissue homogenates. The BATMAN-TCM database was used to retrieve the chemical components and their corresponding targets of Qingfei oral solution by network pharmacology method, and then the component-target-disease network diagram was constructed. Finally, the pathway enrichment analysis was carried out to explore the molecular mechanism of Qingfei oral liquid against idiopathic fibrosis. Histopathology results showed that Qingfei oral liquid had a similar relieving effect on pulmonary fibrosis as the positive drug pirfenidone; TGF-β secretion had a significant reduction in lung tissues of Qingfei group; and Qingfei oral liquid had better regulatory effect on SOD, MDA and GSH than pirfenidone. The results of component-target-disease network and pathway enrichment analysis showed that the related molecular pathways were concentrated in inflammation, extracellular matrix and cytokines. Qingfei oral liquid has a good therapeutic effect on idiopathic pulmonary fibrosis in rats via regulation of inflammation, extracellular matrix and cytokines.

Idiopathic pulmonary fibrosis: Current and future treatment

Objectives

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease characterized by dry cough, fatigue, and progressive exertional dyspnea. Lung parenchyma and architecture is destroyed, compliance is lost, and gas exchange is compromised in this debilitating condition that leads inexorably to respiratory failure and death within 3–5 years of diagnosis. This review discusses treatment approaches to IPF in current use and those that appear promising for future development.

Data Source

The data were obtained from the Randomized Controlled Trials and scientific studies published in English literature. We used search terms related to IPF, antifibrotic treatment, lung transplant, and management.

Results

Etiopathogenesis of IPF is not fully understood, and treatment options are limited. Pathological features of IPF include extracellular matrix remodeling, fibroblast activation and proliferation, immune dysregulation, cell senescence, and presence of aberrant basaloid cells. The mainstay therapies are the oral antifibrotic drugs pirfenidone and nintedanib, which can improve quality of life, attenuate symptoms, and slow disease progression. Unilateral or bilateral lung transplantation is the only treatment for IPF shown to increase life expectancy.

Conclusion

Clearly, there is an unmet need for accelerated research into IPF mechanisms so that progress can be made in therapeutics toward the goals of increasing life expectancy, alleviating symptoms, and improving well‐being.

Inhaled B7 alleviates bleomycin-induced pulmonary fibrosis in mice

Treatment options for the progression of pulmonary fibrosis (PF), which ultimately causes respiratory failure, are limited. According to recent studies, recombinant human relaxin is potentially therapeutic against fibrosis and contraction during pulmonary damage. However, the production of recombinant H2 relaxin is laborious and expensive, limiting its extensive application. Thankfully, alternative research has revealed that treatment with a single-chain peptide of relaxin attenuates organ fibrosis in rodent models too, with the production of a single-chain peptide of relaxin simple and cheap; it could be therapeutic against idiopathic pulmonary fibrosis. Here, we explored the probable inhibiting effects of B7, a B chain of recombinant human relaxin, on bleomycin-induced pulmonary inflammation. Inhaled B7 efficiently reduced the number of inflammatory leukocytes and neutrophils in the bronchoalveolar lavage fluid of mice with bleomycin-induced PF, significantly improved the structure of the damaged alveolar, reduced collagen deposition, suppressed the main pathological features of idiopathic pulmonary fibrosis, i.e. the expression of both pulmonary α-smooth muscle actin and pulmonary vimentin, and inhibited the transcription of inflammation and collagen deposition-related mRNAs, including fibronectin, α-smooth muscle actin (α-SMA), interleukin-1β (IL-1β), interleukin-6 (IL-6), and alpha-1 type 1 collagen (Col-1a), and the expression of inflammation-related proteins, such as IL-1β, IL-6, chemokines (KC), TIMP metallopeptidase inhibitor 1 (TIMP-1), and hydroxyproline (Hyp). Overall, our findings suggest that inhaled B7 exerts beneficial effects against pulmonary fibrosis via attenuating inflammation. It could be developed into a simple, highly effective therapeutic approach for pulmonary fibrosis.