Treatment of bleomycin-induced pulmonary fibrosis by inhaled tacrolimus-loaded chitosan-coated poly(lactic-co-glycolic acid) nanoparticles

Mechanisms of Bleomycin-induced Lung Fibrosis: A Review of Therapeutic Targets and Approaches

Pulmonary toxicity is a serious side effect of some specific anticancer drugs. Bleomycin is a well-known anticancer drug that triggers severe reactions in the lungs. It is an approved drug that may be prescribed for the treatment of testicular cancers, Hodgkin's and non-Hodgkin's lymphomas, ovarian cancer, head and neck cancers, and cervical cancer. A large number of experimental studies and clinical findings show that bleomycin can concentrate in lung tissue, leading to massive oxidative stress, alveolar epithelial cell death, the proliferation of fibroblasts, and finally the infiltration of immune cells. Chronic release of pro-inflammatory and pro-fibrotic molecules by immune cells and fibroblasts leads to pneumonitis and fibrosis. Both fibrosis and pneumonitis are serious concerns for patients who receive bleomycin and may lead to death. Therefore, the management of lung toxicity following cancer therapy with bleomycin is a critical issue. This review explains the cellular and molecular mechanisms of pulmonary injury following treatment with bleomycin. Furthermore, we review therapeutic targets and possible promising strategies for ameliorating bleomycin-induced lung injury.

Chitosan-coated nanoparticles in innovative cancer bio-medicine

In the recent decade, nanoparticles (NPs) have had enormous implications in cancer biomedicine, including research, diagnosis, and therapy. However, their broad application still faces obstacles due to some practical limitations and requires further development. Recently, there has been more interest in the coated class of nanoparticles to address those challenges. Chitosan-coated NPs are simple to produce, biodegradable, biocompatible, exhibit antibacterial activity, and have less cytotoxicity. This study provides an updated and comprehensive overview of the application of chitosan-coated NPs as a promising class of NPs in cancer biomedicine. Additionally, we discussed chitosan-coated lipid, metal, and polymer-based nanoparticles in biomedical applications. Furthermore, different coating methods and production/characterization procedures were reviewed. Moreover, the biological and physicochemical advantages of chitosan-coated NPs, including facilitated controlled release, greater physicochemical stability, improved cell/tissue interaction, and enhanced bioavailability of medications, were highlighted. Finally, the prospects of chitosan-coated NPs in cancer biomedicine were discussed.

Novel inhalation therapy in pulmonary fibrosis: principles, applications and prospects

Pulmonary fibrosis (PF) threatens millions of people worldwide with its irreversible progression. Although the underlying pathogenesis of PF is not fully understood, there is evidence to suggest that the disease can be blocked at various stages. Inhalation therapy has been applied for lung diseases such as asthma and chronic obstructive pulmonary disease, and its application for treating PF is currently under consideration. New techniques in inhalation therapy, such as the application of microparticles and nanoparticles, traditional Chinese medicine monomers, gene therapy, inhibitors, or agonists of signaling pathways, extracellular vesicle interventions, and other specific drugs, are effective in treating PF. However, the safety and effectiveness of these therapeutic techniques are influenced by the properties of inhaled particles, biological and pathological barriers, and the type of inhalation device used. This review provides a comprehensive overview of the pharmacological, pharmaceutical, technical, preclinical, and clinical experimental aspects of novel inhalation therapy for treating PF and focus on therapeutic methods that significantly improve existing technologies or expand the range of drugs that can be administered via inhalation. Although inhalation therapy for PF has some limitations, the advantages are significant, and further research and innovation about new inhalation techniques and drugs are encouraged.

Inhalation Lenalidomide-Loaded Liposome for Bleomycin-Induced Pulmonary Fibrosis Improvement

Idiopathic pulmonary fibrosis (IPF) is a progressive, fibrotic interstitial lung disease with unclear etiology and increasing prevalence. Pulmonary administration can make the drug directly reach the lung lesion location and reduce systemic toxic and side effects. The effectiveness of lenalidomide (Len) liposomal lung delivery in idiopathic pulmonary fibrosis was investigated. Len liposomes (Len-Lip) were prepared from soybean lecithin, cholesterol (Chol), and medicine in different weight ratios by thin film hydration method. The Len-Lip were spherical in shape with an average size of 226.7 ± 1.389 nm. The liposomes with a higher negative zeta potential of around - 34 mV, which was conducive to improving stability by repelling each other. The drug loading and encapsulation rate were 2.42 ± 0.07% and 85.47 ± 2.42%. Len-Lip had little toxicity at the cellular level and were well taken up by cells. At bleomycin-induced pulmonary fibrosis model mice, inhalation Len-Lip could improve lung function and decrease lung hydroxyproline contents, and alleviate pulmonary fibrosis state. Inhalation Len-Lip provided a reference for the treatment of idiopathic pulmonary fibrosis.

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.

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.

Tacrolimus ameliorates bleomycin-induced pulmonary fibrosis by inhibiting M2 macrophage polarization via JAK2/STAT3 signaling

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease of unknown cause and characterized by excessive proliferation of fibroblasts and the irregular remodeling of extracellular matrix (ECM), which ultimately cause the severe distortion of the alveolar architecture. The median survival of IPF patients is 2-5 years. IPF patients are predominantly infiltrated by M2 macrophages during the course of disease development and progression. Predominantly accumulation of M2 macrophages accelerates fibrosis progression by secreting multiple cytokines that promote fibroblast to myofibroblast transition. In the process of M2 macrophage polarization, JAK2/STAT3 signaling plays a key role, thus, targeting activated macrophages to inhibit the pro-fibrotic phenotype is considered as an approach to the potential treatment of IPF. Tacrolimus is a macrolide antibiotic that as a specific inhibitor of T-lymphocyte function and has been used widely as an immunosuppressant in human organ transplantation. In this study we explored the potential effect and mechanism of tacrolimus on pulmonary fibrosis in vivo and vitro. Here, we found that tacrolimus is capable of suppressing M2 macrophages polarization by inhibiting pro-fibrotic factors secreted by M2 macrophages. This effect further alleviates M2-induced myofibroblast activation, thus resulting in a decline of collagen deposition, pro-fibrotic cytokines secretion, recovering of lung function, ultimately relieving the progression of fibrosis in vivo. Mechanistically, we found that tacrolimus can inhibit the activation of JAK2/STAT3 signaling by targeting JAK2. Our findings indicate a potential anti-fibrotic effect of tacrolimus by regulating macrophage polarization and might be meaningful in clinical settings.

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.

An Update on Advancements and Challenges in Inhalational Drug Delivery for Pulmonary Arterial Hypertension

A lethal condition at the arterial–alveolar juncture caused the exhaustive remodeling of pulmonary arterioles and persistent vasoconstriction, followed by a cumulative augmentation of resistance at the pulmonary vascular and, consequently, right-heart collapse. The selective dilation of the pulmonary endothelium and remodeled vasculature can be achieved by using targeted drug delivery in PAH. Although 12 therapeutics were approved by the FDA for PAH, because of traditional non-specific targeting, they suffered from inconsistent drug release. Despite available inhalation delivery platforms, drug particle deposition into the microenvironment of the pulmonary vasculature and the consequent efficacy of molecules are influenced by pathophysiological conditions, the characteristics of aerosolized mist, and formulations. Uncertainty exists in peripheral hemodynamics outside the pulmonary vasculature and extra-pulmonary side effects, which may be further exacerbated by underlying disease states. The speedy improvement of arterial pressure is possible via the inhalation route because it has direct access to pulmonary arterioles. Additionally, closed particle deposition and accumulation in diseased tissues benefit the restoration of remolded arterioles by reducing fallacious drug deposition in other organs. This review is designed to decipher the pathological changes that should be taken into account when targeting the underlying pulmonary endothelial vasculature, especially with regard to inhaled particle deposition in the alveolar vasculature and characteristic formulations.

Nanotechnology-based therapeutics for targeting inflammatory lung diseases

The physiochemical properties of drugs used in treating inflammation-associated lung diseases (i.e., asthma, chronic obstructive pulmonary disease, pulmonary fibrosis) play an important role in determining the effectiveness of formulations. Most commonly used drugs are associated with low solubility, low stability and rapid clearance, thus resulting in low bioavailability and therapeutic index. This review focuses on current trends and development of drugs (i.e., corticosteroids, long-acting β-agonists and biomacromolecules such as DNA, siRNA and mRNA) employed to treat inflammatory lung diseases. In addition, this review includes the current challenges of and future perspective with regard to nanotechnology in the treatment of inflammatory lung diseases.

Emerging drug delivery strategies for idiopathic pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) is a debilitating and fatal condition that causes severe scarring of the lungs. While the pathogenesis of IPF continues to be extensively studied and several factors have been considered, an exact cause has yet to be established. With inadequate treatment options and no cure available, overall disease prognosis is still poor. Existing oral therapies, pirfenidone and nintedanib, may attempt to improve the patients' quality of life by mitigating symptoms and slowing disease progression, however chronic doses and systemic deliveries of these drugs can lead to severe side effects. The lack of effective treatment options calls for further investigation of restorative as well as additional palliative therapies for IPF. Nanoparticle-based sustained drug delivery strategies can be utilized to ensure targeted delivery for site-specific treatment as well as long-acting therapy, improving overall patient compliance. This review provides an update on promising strategies for the delivery of anti-fibrotic agents, along with an overview of key therapeutic targets as well as relevant emerging therapies currently being evaluated for IPF treatment.

Bleomycin-Loaded pH-Sensitive Polymer⁻Lipid-Incorporated Liposomes for Cancer Chemotherapy

Cancer chemotherapeutic systems with high antitumor effects and less adverse effects are eagerly desired. Here, a pH-sensitive delivery system for bleomycin (BLM) was developed using egg yolk phosphatidylcholine liposomes modified with poly(ethylene glycol)-lipid (PEG-PE) for long circulation in the bloodstream and 2-carboxycyclohexane-1-carboxylated polyglycidol-having distearoyl phosphatidylethanolamine (CHexPG-PE) for pH sensitization. The PEG-PE/CHexPG-PE-introduced liposomes showed content release responding to pH decrease and were taken up by tumor cells at a rate 2.5 times higher than that of liposomes without CHexPG-PE. BLM-loaded PEG-PE/CHexPG-PE-introduced liposomes exhibited comparable cytotoxicity with that of the free drug. Intravenous administration of these liposomes suppressed tumor growth more effectively in tumor-bearing mice than did the free drug and liposomes without CHexPG-PE. However, at a high dosage of BLM, these liposomes showed severe toxicity to the spleen, liver, and lungs, indicating the trapping of liposomes by mononuclear phagocyte systems, probably because of recognition of the carboxylates on the liposomes. An increase in PEG molecular weight on the liposome surface significantly decreased toxicity to the liver and spleen, although toxicity to the lungs remained. Further improvements such as the optimization of PEG density and lipid composition and the introduction of targeting ligands to the liposomes are required to increase therapeutic effects and to reduce adverse effects.

Compatibility of PEGylated Polymer Nanoparticles with the Biophysical Function of Lung Surfactant

To minimize an unwanted interference of colloidal drug delivery vehicles with the biophysical functionality of lung surfactant, the surface of polymer nanoparticles was modified with poly(ethylene glycol) (PEGylation). Plain poly(lactide) nanoparticles provoked a statistically relevant decrease in the surface activity of the naturally derived lung surfactant, Alveofact. By contrast, the extent of lung surfactant inhibition induced by PEGylated polymer nanoparticles was significantly attenuated. Here, escalations of the PEG coating layer thickness (>3 nm, with a chain-to-chain distance of ≤4 nm) on the colloidal surface were capable of circumventing bioadverse effects. Accordingly, polymer nanoparticles equipped with PEG chains with a molecular weight above 2-5 kDa were compatible with the biophysical function of Alveofact. Overall, PEGylation of polymer nanoparticles presents a promising approach for the development of inhalation nanomedicines revealing negligible effects on the surface activity of the lining layer present in the deep lungs.