Search Results (63)

Background and objectives: Occupational and environmental inhalation exposures, including high-aspect-ratio carbon nanotubes, can trigger pulmonary fibrosis (PF). The relationship between exposure-specific fibrogenic pathways (granulomatous inflammation versus diffuse epithelial injury) and lung microbiome dysbiosis remains incompletely understood. We therefore compared lung microbiome alterations in rat PF models induced by multi-walled carbon nanotubes (MWCNTs) and bleomycin. Materials and Methods: Female Wistar rats received a single intratracheal instillation of vehicle, MWCNTs (750 μg/rat), or bleomycin (1 mg/rat). At day 28, fibrosis and inflammation were evaluated by histopathology and bronchoalveolar lavage fluid (BALF) profiling. Lung microbial communities were characterized by 16S rRNA gene sequencing (V3–V4). Seventeen lung samples passed stringent quality control and were analyzed (control n = 5; bleomycin n = 7; MWCNT n = 5). Results: Both agents induced PF with increased profibrotic signaling, but with distinct pathological signatures: MWCNTs produced localized granulomatous lesions and a robust neutrophilic response (25% of BALF cells), whereas bleomycin caused diffuse interstitial remodeling. Bleomycin increased microbial richness (alpha diversity; p < 0.05) and significantly shifted community structure (beta diversity; p < 0.05), while MWCNT exposure showed comparatively limited changes in global diversity. The relative abundance of Pseudogracilibacillus (including P. marinus) was higher in the bleomycin group than in controls, whereas Facklamia tabacinasalis and Corynebacterium maris were more abundant in the MWCNT group. Across samples, Proteobacteria abundance was inversely correlated with BALF TGF-β, MCP-1, and neutrophil proportion. At the species level, Pseudogracilibacillus marinus was positively correlated with BALF TGF-β, while Facklamia tabacinasalis and Corynebacterium maris were positively correlated with MCP-1, CINC-3, and neutrophil proportion (Spearman; p < 0.05). Conclusions: Mechanistically distinct fibrogenic exposures generate exposure-linked lung microbiome signatures that track with host inflammatory and profibrotic responses. These signatures may support biomarker development for environmentally and occupationally relevant PF and motivate longitudinal and functional studies to clarify causality. Full article

Extremely preterm infants often require prolonged respiratory support due to lung immaturity and inflammation, placing them at high risk of lung injury and development of bronchopulmonary dysplasia (BPD). In many of these infants, systemic postnatal corticosteroids are used to reduce lung inflammation, facilitate mechanical ventilation (MV) weaning and extubation, and improve short-term pulmonary outcomes. However, despite decades of clinical use, substantial variation persists in timing, choice of agent and dosing. These inconsistencies reflect a lack of strong evidence and a limited understanding of the systemic and organ-specific effects of therapy for a highly heterogenous population usually exposed to this medication. This narrative review addresses these gaps by integrating current knowledge of the inflammatory and respiratory effects of postnatal corticosteroids in extremely preterm infants. We explore how corticosteroids modulate pulmonary inflammation, their effects on lung development, and how they affect key clinical outcomes such as extubation success and BPD severity. We also examine evolving approaches to corticosteroid administration and dosing, highlighting the importance of individualized strategies informed by developmental and disease-specific considerations. Comparative data from randomized controlled trials are reviewed, including the efficacy and side-effect profiles of commonly used regimens. Current evidence supports judicious use of late low-dose dexamethasone, while early prophylaxis with inhaled or intratracheal steroids remains experimental and is not routinely advised. In line with a physiology-driven approach, we also discuss emerging domain-specific monitoring tools that may enhance patient selection and optimize timing of intervention. By synthesizing mechanistic insights with clinical evidence, this review supports a more nuanced, individualized approach to postnatal corticosteroid therapy in extremely preterm infants, balancing therapeutic benefits with potential systemic trade-offs. Full article

Background/Objectives: This review summarizes and analyzes current data on the toxicological effects of cerium dioxide nanoparticles (nanoceria) on various anatomical and functional systems in healthy murine models, as reported in both in vivo and ex vivo experimental settings. Methods: This systematic review was conducted and reported in accordance with the PRISMA 2020 guidelines and was prospectively registered in PROSPERO (CRD42024503240). A systematic literature search was conducted using the PubMed and ScienceDirect databases for the period 2019–2025, with the inclusion of earlier publications having significant scientific relevance. The final search update was conducted in July 2025 to ensure inclusion of the most recent studies. Results and Conclusions: Only in vivo and ex vivo studies in healthy murine models were included. Risk of bias was evaluated using the OHAT tool for animal studies, and data were synthesized narratively due to heterogeneity among studies. A total of 29 studies met the inclusion criteria. The pharmacokinetic properties of nanoceria were considered, encompassing biodistribution, elimination pathways (including oral, intravenous, intraperitoneal, inhalation, intratracheal, and instillation routes), and the influence of physicochemical characteristics on bioavailability and toxicity. The toxicological impact (TI) was assessed across major organ systems—respiratory, digestive, urinary, visual, reproductive, nervous, cardiovascular, immune, hematopoietic, endocrine, musculoskeletal, and skin. The liver, spleen, lungs, and kidneys were identified as primary accumulation sites, with clearance dependent on particle size and coating. The TI spectrum ranged from the absence of morphological changes to inflammation, fibrosis, or organ dysfunction, depending on dose, exposure route, and physicochemical parameters. The main limitations include variability of nanoparticle formulations and incomplete toxicity reporting. In general, CeO₂ nanoparticles with sizes of 2–10 nm and doses ≤ 5 mg/kg showed no signs of systemic toxicity in short-term studies on healthy mice, provided that optimal coating and dosing intervals were used. Full article

Inhalation of multi-walled carbon nanotubes (MWCNTs) poses potential health risks due to their structural similarity to asbestos and their ability to induce chronic lung inflammation, fibrosis, and lung cancer in animal models. This study investigated the pulmonary inflammatory and transcriptomic responses of two distinct MWCNTs—NM-401 (long, rigid) and NM-403 (short, thin)—in rats and mice using intratracheal instillation at matched dose levels at two post-exposure time points. Both MWCNTs induced acute neutrophilic inflammation and dose-dependent transcriptomic alterations in both species, with NM-403 eliciting a stronger response. Transcriptomic profiling revealed a substantial overlap in differentially expressed genes across materials and species, particularly at the early time point. Fibrosis-associated genes were upregulated in both species, with more persistent expression observed in rats. Acute phase response genes, including Orosomucoid 1 and Lipocalin 2 were commonly induced, while Serum Amyloid A3 and Orosomucoid 2 were selectively upregulated in mice. Functional enrichment analyses showed conserved activation of immune and inflammatory pathways. Our findings show that even short, non-fiber-like MWCNTs can provoke potent and persistent pulmonary effects, challenging assumptions based solely on MWCNT properties. Despite differences in long-term responses, the overall inflammatory and transcriptional profiles showed strong interspecies concordance, suggesting that both rats and mice are relevant models for assessing MWCNT-induced pulmonary toxicity. Full article

Background: Microplastics (MPs) can be inhaled by people. However, the relationships between long-term exposure to inhaled MPs, pulmonary fibrosis, and mitochondrial dysfunction are not completely clear. Methods: SD rats were exposed to a 0.0125, 0.125, 0.31, or 1.25 mg/day dosage of mixed polystyrene MPs (PS-MPs), with the particle sizes ranging from 500 nm to 4 µm, via intratracheal administration, for 7 to 35 consecutive days. Results: PS-MPs with particle sizes ranging from 1 µm to 4 µm were deposited in the lungs. The contents of NFκB-mediated proinflammatory cytokines were increased in the lungs of the rats after 7 days of PS-MP exposure. After exposure to PS-MPs, the degree of collagen deposition and the expression of TGF-β1/Smad increased significantly, and the levels of phosphorylated Akt (p-Akt) and nuclear β-catenin decreased significantly. The number of healthy mitochondria decreased, the expression of mitochondrial fission and fusion proteins increased, and the level of PINK1/Parkin-mediated mitophagy decreased in the lungs of the rats after 7 days of PS-MP exposure. A benchmark dose (BMD) of 0.151 mg/day and a benchmark dose lower confidence limit (BMDL) of 0.031 mg/day were identified on the basis of the subchronic effects of the intratracheal administration of the PS-MPs. Conclusions: Our study provides an in-depth understanding of the potential impacts of MP pollution on respiratory diseases. Full article

In South Korea, issues have been raised regarding exposure to humidifier disinfectant products containing certain chemicals postulated to induce lung diseases in consumers. Several rodent studies utilizing whole-body inhalation, which comprises freely moving animals breathing through the nares, and intranasal instillation involving restraint, were conducted by various Korean Governmental Agencies on these products to investigate whether there is a causal relationship between these products and the development of lung diseases. In particular, the humidifier disinfectant product Kathon, containing chloromethylisothiazolinone and methylisothiazolinone (CMIT and MIT), when directly introduced into inhalation chambers at varying concentrations for up to 13 weeks, produced no significant histopathological alterations and no marked changes in pulmonary function parameters. Further, there was no evidence of cytotoxicity; total and differential cell counts did not differ from control. In addition, the levels of cytokine markers of inflammation were not markedly altered. In contrast to published papers utilizing intratracheal and intranasal instillation, where the animal is anesthetized and chemical bypasses the defense mechanisms in the respiratory tract, then reaches the pulmonary region, ignoring recommended dose levels was found to initiate fibrotic responses in mice and rats. However, the usefulness of experimental results to extrapolate to humans obtained following intratracheal and intranasal instillation studies is of limited value because the data generated did not use a realistic design and appropriate dosimetry. Therefore, these findings have significant drawbacks in their use to characterize an inhalation risk for pulmonary fibrosis in humans and cannot be used for the extrapolation of such risk to humans. It is thus evident that the inhalation data generated by the Korean Regulatory Agencies are more realistic and show that exposure to CMIT and MIT does not initiate pulmonary fibrosis. Although inhalation studies still do not fully replicate real-world human exposure scenarios and have limitations for direct extrapolation to humans, they are nevertheless more appropriate than intratracheal or intranasal instillation models. Full article

Background/Objectives: This study aimed to develop a dry powder inhalation (DPI) formulation of rivaroxaban (RVX) using a combination of bead milling (BM) and jet milling (JM) to enhance lung-targeted delivery for the effective treatment of pulmonary embolism while minimizing systemic exposure. Methods: A carrier-free DPI formulation of RVX was developed using sequential BM and JM, with L-leucine incorporated at various concentrations (1%, 5%, and 10%) as a force control agent. The formulations were characterized for particle morphology, size distribution, crystallinity, and thermal properties. The in-vitro aerodynamic performance was evaluated using a next-generation impactor, while ex-vivo studies assessed anticoagulant activity. Pharmacokinetic and tissue distribution studies were carried out in Sprague Dawley rats following intratracheal administration, and the effects of inhaled RVX were compared with those of oral administration. Results: The optimized BM-JM-5L formulation achieved a Dv50 of 2.58 ± 0.01 µm and a fine particle fraction of 72.10 ± 2.46%, indicating suitability for pulmonary delivery. The two-step milling effectively reduced particle size and enhanced dispersibility without altering RVX’s physicochemical properties. Ex-vivo anticoagulation tests confirmed maintained or improved activity. In-vivo studies showed that pulmonary administration (5 mg/kg) led to a 493-fold increase in lung drug concentration and 2.56-fold higher relative bioavailability vs. oral dosing, with minimal heart tissue accumulation, confirming targeted lung delivery. Conclusions: The two-step milled RVX DPI formulations, particularly BM-JM-5L with 5% leucine, demonstrated significant potential for pulmonary administration by achieving high local drug concentrations, rapid onset, and improved bioavailability at lower doses. These findings highlight the feasibility of RVX as a DPI formulation for pulmonary delivery in treating pulmonary embolism. Full article

Background: The preparation of antibodies in powder form without changing their physicochemical properties may enable their use in new drug delivery system therapies or non-refrigerated storage. The variable domain of heavy-chain antibodies (VHHs) is more suited for this purpose than that of conventional antibodies because of VHHs’ high thermal stability and ability to refold. Methods: In this report, the fine droplet drying (FDD) process was selected as the powderization technique because of its favorable features, such as mild drying conditions and the generation of uniform particle sizes. The aggregation, binding, particle, and in vitro inhalation properties of the prepared VHH powders (VHHps) were evaluated. Results: The amount of aggregated VHHs present in the VHHps depended on the flow temperature during the FDD process, with higher temperatures yielding a higher aggregation ratio. In contrast, no significant difference in binding activity was observed between each VHHp preparation and the native VHHs. However, this process degraded VHHs or inactivated their function, and ultimately, only about 30% of the original VHHs were functional, whereas the remaining VHHs that were not degraded showed little loss of functionality, even after storage at room temperature for more than two years. Analysis of the VHHp samples revealed that the particles were uniformly spherical with a single-micron size. The VHHps showed fine inhalation properties in the inhalation property test. Conclusions: These findings suggest that the FDD process affords various VHH powder formulations, including pharmaceutical formulations. Full article

Background/Objectives: Inhalation of environmental particulate air pollution has been reported to cause pulmonary and systemic events including coagulation disturbances, systemic inflammation, and oxidative stress. Nerolidol, a naturally occurring sesquiterpene alcohol, has effective antioxidant and anti-inflammatory effects. Hence, the aim in the present investigation was to evaluate the potential ameliorative effects of nerolidol on the coagulation and systemic actions induced by pulmonary exposure to diesel exhaust particles (DEPs). Methods: Nerolidol (100 mg/kg) was given to mice by oral gavage one hour before the intratracheal instillation of DEPs (0.5 mg/kg), and 24 h later various markers of coagulation and systemic toxicity were evaluated. Results: Nerolidol treatment significantly abrogated DEP-induced platelet aggregation in vivo and in vitro. Nerolidol has also prevented the shortening of the prothrombin time and activated plasma thromboplastin time triggered by DEP exposure. Likewise, while the concentrations of fibrinogen and plasminogen activator inhibitor-1 were increased by DEP administration, that of tissue plasminogen activator was significantly decreased. These effects were abolished in the group of mice concomitantly treated with nerolidol and DEP. Moreover, plasma markers of inflammation, oxidative stress, and endothelial dysfunction which were significantly increased in the DEP-treated group, returned to control levels in the nerolidol + DEP group. Nerolidol treatment significantly ameliorated the increase in the concentrations of hypoxia-inducible factor 1α, galectin-3, and neutrophil gelatinase-associated lipocalin induced by pulmonary exposure to DEP. The co-administration of nerolidol + DEPs significantly mitigated the increase in markers of oxidative DNA damage, 8-hydroxy-2-deoxyguanosine, and apoptosis, cleaved-caspase-3, induced by DEP. Conclusions: Collectively, our data demonstrate that nerolidol exert significant ameliorative actions against DEP-induced thrombotic events, endothelial dysfunction, systemic inflammation, oxidative stress, DNA damage, and apoptosis. Pending further pharmacological and toxicological studies, nerolidol could be a promising agent to alleviate the toxicity of inhaled DEPs and other pollutant particles. Full article

Background/Objectives: Inhaler devices have been developed for the effective delivery of inhaled medications used in the treatment of pulmonary diseases. However, differing operating procedures across the devices can lead to user errors and reduce treatment efficacy, especially when patients use multiple devices simultaneously. To address this, we developed a novel dry powder inhaler (DPI), combining fluticasone propionate (FP), salmeterol xinafoate (SX), and tiotropium bromide (TB) into a single device designed for bioequivalent delivery compared to existing commercial products in an animal model. Methods: The micronized FP/SX/TB-loaded capsule was prepared by sieving, blending, and filling capsules. Capsule suitability of the drugs was investigated from the comparison of the stability of drugs within various capsule formulations to that of commercial products. The particle size of the drugs was adjusted using spiral air jet milling, and the ratio of lactose hydrate carriers was optimized by comparing the aerodynamic particle size distribution (APSD) with that of commercial products. To investigate the bioequivalence of micronized FP/SX/TB-loaded DPI to commercial products, the dissolution profile of FP/SX/TB particles and pharmacokinetics in rats were evaluated and compared to commercial products. Results: Capsules with hydroxypropyl methylcellulose (HPMC) without a gelling agent showed superior stability of the drugs compared to commercial products. The deposition pattern was influenced by the particle size of the drugs, and fine particle mass exhibited a significant correlation with the amount of fine carrier. Micronized FP/SX/TB-loaded DPI gave a similar APSD and dissolution profile compared to the commercial products and showed dose uniformity by the DPI device. Furthermore, micronized FP/SX/TB-loaded DPI exhibited bioequivalence to commercial products, as evidenced by no significant differences in pharmacokinetic parameters following intratracheal administration in rats. Conclusions: A novel triple-combination DPI containing FP/SX/TB was successfully developed, demonstrating comparable pharmacological performance to commercial products. Optimized FP/SX/TB-loaded DPI with HPMC capsule achieved bioequivalence in rat studies, suggesting its potential for improved patient compliance and therapeutic outcomes. This novel single-device DPI offers a promising alternative for triple therapy in pulmonary diseases. Full article

Background/objectives: Idiopathic pulmonary fibrosis (IPF) is a prevalent interstitial lung disease that typically progresses gradually, leading to respiratory failure and ultimately death. IPF can be treated with the tyrosine kinase inhibitor, nintedanib (NTD), owing to its anti-fibrotic properties, which ameliorate the impairment of lung function. This study aimed to formulate, optimize, and assess NTD-loaded ufasomes (NTD-UFSs) as a nanosystem for its pulmonary targeting to snowball the bioavailability and therapeutic efficacy of the drug. Methods: To investigate the influence of numerous factors on NTD-UFSs assembly and to determine the optimal formulation, Box–Behnken statistical design was implemented with the assistance of Design-Expert^® software. The thin-film hydration strategy was employed to fabricate NTD-UFSs. The optimum NTD-UFSs formulation was subsequently selected and subjected to additional evaluations. Also, using a rat model, a comparative pharmacokinetic analysis was scrutinized. Results: The optimal NTD-UFSs elicited an accumulative release of 65.57% after 24 h, an encapsulation efficiency of 62.51%, a zeta potential of −36.07 mV, and a vesicular size of 364.62 nm. In addition, it disclosed remarkable stability and a continuous cumulative release pattern. In vivo histopathological studies ascertained the tolerability of NTD-UFSs administered intratracheally. According to the pharmacokinetic studies, intratracheal NTD-UFSs administration manifested a significantly higher AUC_0–∞ value than oral and intratracheal NTD suspensions, by approximately 5.66- and 3.53-fold, respectively. Conclusions: The findings of this study proposed that UFSs might be a promising nanoparadigm for the non-invasive pulmonary delivery of NTD. Full article

Objective: To establish and validate an LC-MS/MS method for the simultaneous determination of curcumin (CUR) as well as its glucuronide conjugate (COG) and sulfate conjugate (COS) in rat plasma. The method was employed to evaluate and compare the pharmacokinetic behaviors of curcumin following oral and intratracheal administration in rats. Methods: Rat plasma samples were separated by chromatography on a C18 column after protein precipitation with acetonitrile. Gradient elution with a mobile phase of 0.5 mM ammonium acetate in acetonitrile was utilized. Mass spectrometry detection incorporated an electrospray ionization (ESI) source, multiple reaction monitoring (MRM), and dual-mode (positive and negative) scanning for quantitative analysis. A total of 12 SD rats were randomly divided into two groups and were orally (20 mg/kg) or intratracheally (10 mg/kg) administrated curcumin, respectively. CUR, COG, and COS concentrations in plasma were measured to assess pharmacokinetic disparities. Results: The method demonstrated linearity within the ranges of 2–400 ng/mL for CUR and COS and 5–1000 ng/mL for COG. Intratracheal administration significantly elevated CUR plasma concentrations compared to oral administration. The exposure of COG was higher than COS following oral administration. Conversely, intratracheal administration resulted in markedly higher COS exposure, with no significant difference in COG exposure after dose normalization between oral and inhalation routes. Conclusions: The established LC-MS/MS method provides a reliable tool for the simultaneous measurement of CUR, COG, and COS in rat plasma, facilitating preclinical pharmacokinetic investigations. The study reveals distinct pharmacokinetic profiles for CUR following oral versus intratracheal administration, suggesting that inhalation may offer superior therapeutic efficacy. Full article

Pulmonary emphysema involves progressive destruction of alveolar walls, leading to enlarged air spaces and impaired gas exchange. While the precise mechanisms responsible for these changes remain unclear, there is growing evidence that the extracellular matrix plays a critical role in the process. An essential feature of pulmonary emphysema is damage to the elastic fiber network surrounding the airspaces, which stores the energy needed to expel air from the lungs. The degradation of these fibers disrupts the mechanical forces involved in respiration, resulting in distension and rupture of alveolar walls. While the initial repair process mainly consists of elastin degradation and resynthesis, continued alveolar wall injury may be associated with increased collagen deposition, resulting in a mixed pattern of emphysema and interstitial fibrosis. Due to the critical role of elastic fiber injury in pulmonary emphysema, preventing damage to this matrix component has emerged as a potential therapeutic strategy. One treatment approach involves the intratracheal administration of hyaluronan, a polysaccharide that prevents elastin breakdown by binding to lung elastic fibers. In clinical trials, inhalation of aerosolized HA decreased elastic fiber injury, as measured by the release of the elastin-specific cross-linking amino acids, desmosine, and isodesmosine. By protecting elastic fibers from enzymatic and oxidative damage, aerosolized HA could alter the natural history of pulmonary emphysema, thereby reducing the risk of respiratory failure. Full article

The widespread biomedical and commercial applications of silver nanoparticles (AgNPs) have increased their potential for human and environmental exposure and toxicity to human health. The bio-distribution and toxicity of AgNPs in rodents following inhalation, intratracheal instillation, and oral ingestion are well documented; however, little is known about the bio-distribution of intravenously (IV)-administered AgNPs and their organ-specific pathophysiological effects. Here, we investigate the pharmacokinetic pattern and tissue distribution of AgNPs in male rats following IV administration. The animals were humanely sacrificed after 10 min, 1 h, 6 h, 12 h, 24 h, and 168 h of AgNP administration, and the silver (Ag) content was measured from blood samples and various tissues following acid digestion. The AgNPs were readily absorbed and subsequently distributed into most organs predominantly in the colon, small intestine, kidney, and heart after 6 h; however, they were the highest in the spinal cord after 168 h. White blood cells (WBCs) were significantly increased (42–60%) in AgNP-administered animals at all time points except 10 min. Regarding platelets, all AgNP-administered animals showed counts 7.8–39.2% lower, with the lowest count at 168 h post-administration. In the case of lymphocytes (LYMs), the AgNP-treated animals exhibited a count 19.5–41% lower at 10 min and 1 h post-administration; however, the animals at 168 h post-administration showed a count 30.5% more. The mean corpuscular hemoglobin (MCH) counts from the AgNP-treated animals were decreased by 50–62%. The concentrations of aspartate transaminase (AST), urea, and creatinine were increased in the AgNP-treated animals. Taken together, the results suggest that the acute IV administration of AgNPs alters metabolic and hematological parameters in animals and may pose a health risk to humans. Full article

Guanidine disinfectants are important chemical agents with a broad spectrum of activity that are effective against most microorganisms. Chlorhexidine, one of the most used guanidine disinfectants, is added to shampoo and mouthwash and applied in medical device sterilization. During the use of chlorhexidine, aerosols with micron particle size may be formed, which may cause inhalation toxicity. To assess the toxicity of inhaled chlorhexidine aerosol, mice underwent the intratracheal instillation of different concentrations of chlorhexidine (0, 0.125%, 0.25%, 0.5%, and 1%) using a MicroSprayer Aerosolizer. The mice were exposed for eight weeks and then sacrificed to obtain lung tissue for subsequent experiments. Histopathology staining revealed damaged lung tissues and increased collagen exudation. At the same time, pulmonary function tests showed that chlorhexidine exposure could cause restrictive ventilatory dysfunction, consistent with pulmonary fibrosis. The results of transcriptome analyses suggest that chlorhexidine may trigger an inflammatory response and promote the activation of pathways related to extracellular matrix deposition. Further, we identified that chlorhexidine exposure might enhance mucus secretion by up-regulating Muc5b and Muc5ac genes, thereby inducing fibrosis-like injury. These findings underscore the need for standardized use of disinfectants and the assessment of their inhalation toxicity. Full article