Pulmonary administration of 1,25-dihydroxyvitamin D3 to the lungs induces alveolar regeneration in a mouse model of chronic obstructive pulmonary disease

Am80-Encapsulated Lipid Nanoparticles, Developed with the Aim of Achieving Alveolar Regeneration, Have an Improvement Effect on Pulmonary Emphysema

Chronic obstructive pulmonary disease (COPD) is characterized by chronic bronchitis and emphysema, and current drug treatments target its symptoms. Thus, the development of a therapeutic drug to repair alveolar destruction is urgently needed. Our previous research revealed that the synthetic retinoic acid Am80 (1.0 mg/kg) showed a repairing effect on collapsed alveoli in a mouse model of elastase-induced emphysema. However, a further reduction in the dose is desirable to facilitate the development of a powder inhalation formulation for clinical application. We, therefore, focused on SS-OP to deliver Am80 efficiently. As a result, 0.01 mg/kg of Am80-encapsulated SS-OP nanoparticles repaired collapsed alveoli and improved the respiratory function in the mouse model of elastase induced emphysema. The results suggested that, with the use of SS-OP, the Am80 dose could be reduced. This could contribute to the development of a powder inhalation system as a curative medicine for COPD.

Effects of Fdft 1 gene silencing and VD3 intervention on lung injury in hypoxia-stressed rats

BACKGROUND

Hypoxia can induce lung injury such as pulmonary arterial hypertension and pulmonary edema. And in the rat model of hypoxia-induced lung injury, the expression of Farnesyl diphosphate farnesyl transferase 1 (Fdft 1) was highly expressed and the steroid biosynthesis pathway was activated. However, the role of Fdft 1 and steroid biosynthesis pathway in hypoxia-induced lung injury remains unclear.

OBJECTIVE

The study aimed to further investigate the relationship between Fdft1 and steroid biosynthesis pathway with hypoxia-induced lung injury.

METHODS

A rat model of lung injury was constructed by hypobaric chamber with hypoxic stress, the adenovirus interference vector was used to silence the expression of Fdft 1, and the exogenous steroid biosynthesis metabolite Vitamin D3 (VD3) was used to treat acute hypoxia-induced lung injury in rats.

RESULTS

Sh-Fdft 1 and exogenous VD3 significantly inhibited the expression of Fdft 1 and the activation of the steroid pathway in hypoxia-induced lung injury rats, which showed a synergistic effect on the steroid activation pathway. In addition, sh-Fdft 1 promoted the increase of pulmonary artery pressure and lung water content, the decrease of oxygen partial pressure and oxygen saturation, and leaded to the increase of lung cell apoptosis and the aggravation of mitochondrial damage in hypoxia-stressed rats. And VD3 could significantly improve the lung injury induced by hypoxia and sh-Fdft 1 in rats.

CONCLUSIONS

Fdft 1 gene silencing can promote hypoxic-induced lung injury, and exogenous supplement of VD3 has an antagonistic effect on lung injury induced by Fdft 1 gene silencing and hypoxic in rats, suggesting that VD3 has a preventive and protective effect on the occurrence and development of hypoxia-induced lung injury.

Impaired Alveolar Re-Epithelialization in Pulmonary Emphysema

Alveolar type II (ATII) cells are progenitors in alveoli and can repair the alveolar epithelium after injury. They are intertwined with the microenvironment for alveolar epithelial cell homeostasis and re-epithelialization. A variety of ATII cell niches, transcription factors, mediators, and signaling pathways constitute a specific environment to regulate ATII cell function. Particularly, WNT/β-catenin, YAP/TAZ, NOTCH, TGF-β, and P53 signaling pathways are dynamically involved in ATII cell proliferation and differentiation, although there are still plenty of unknowns regarding the mechanism. However, an imbalance of alveolar cell death and proliferation was observed in patients with pulmonary emphysema, contributing to alveolar wall destruction and impaired gas exchange. Cigarette smoking causes oxidative stress and is the primary cause of this disease development. Aberrant inflammatory and oxidative stress responses result in loss of cell homeostasis and ATII cell dysfunction in emphysema. Here, we discuss the current understanding of alveolar re-epithelialization and altered reparative responses in the pathophysiology of this disease. Current therapeutics and emerging treatments, including cell therapies in clinical trials, are addressed as well.

Optimization of Very Low-Dose Formulation of Vitamin D3 with Lyophilizate for Dry Powder Inhalation System by Simple Method Based on Time-of-Flight Theory

It has been previously reported that active vitamin D3 (VD3) is a candidate drug that can repair alveolar damage in chronic obstructive pulmonary disease at a very low dose. We herein report the optimization of a very low-dose formulation of VD3 for dry powder inhalation by a simple method based on time-of-flight (TOF) theory. As the preparation content of VD3 is very low, aerodynamic particle size distribution cannot be measured by pharmacopeial methods that require quantification of the main drug. Thus, a simple method based on TOF theory, which can measure aerodynamic particle size distribution without quantification, was used. The optimized formulation for an inhalation system using a lyophilized cake contained phenylalanine as the excipient (VD3 1 μg/vial + phenylalanine 0.3 mg/vial) and showed high performance with fine particle fraction ≤ 3 μm = 47.2 ± 4.4%. The difference between the results of pharmacopeial methods and simple method was examined using the formulation containing 10 µg/vial of VD3 and was within 5.0%. The preparation is expected to efficiently deliver VD3 to the lungs. Our simple method can optimize dry powder inhalation formulations more easily and rapidly even when the content of the main drug in a preparation is very low.

A Comprehensive Review on Vitamin D as a Novel Therapeutic Agent in Chronic Obstructive Pulmonary Disease

Vitamin D has been playing an important role in the treatment of lung diseases. The non-calcemic effects of this vitamin and its role in chronic obstructive pulmonary disease (COPD) has drawn significant attention recently. Many studies have been conducted to explore the relationship between the two. We tested the hypothesis that vitamin D can act as an effective therapeutic agent for COPD by reviewing the correlation between the two and effectiveness along with the safety of supplemental vitamin D when used to treat chronic bronchitis and emphysema through clinical trials. An electronic search was conducted using combinations of keywords “vitamin D” and “COPD” from PubMed and Google scholar. Only relevant, human studies of all types were included from the last decade. A total of 36 articles were selected for review. Observational studies indicate a correlation between low serum 25(OH)D levels and obstructive lung disease pathology as well as clinical outcomes. Moreover, clinical trials were aimed to understand the impact of the use of vitamin D in improving disease indexes. These clinical trials used different drug regimes, mode of administration, and intervention duration with contrasting outcomes.

Hypovitaminosis D is a common and harmful variant of this group of obstructive lung diseases, and correcting this deficiency can improve exacerbations, inflammation, lung functions, symptoms, and quality of life. These benefits are more prevalent in patients with low baseline serum 25 hydroxyvitamin D(25(OH)D) levels. Peroral is the most frequently used route of drug administration, however, further work is required to explore the pharmacological properties of vitamin D. There was not enough literature available about the safety of the drug of intervention.

Low Vitamin D Status Is Associated with Inflammation in Patients with Chronic Obstructive Pulmonary Disease

Vitamin D deficiency is associated with increased risks of chronic obstructive pulmonary disease (COPD). Nevertheless, the mechanisms remain unknown. This study analyzed the correlations between vitamin D levels and inflammation in COPD patients. One hundred and one patients with COPD and 202 control subjects were enrolled. Serum 25(OH)D level and inflammatory cytokines were detected. Serum 25(OH)D was decreased and inflammatory cytokines were increased in COPD patients. According to forced expiratory volume in 1 s, COPD patients were divided into three grades. Furthermore, serum 25(OH)D was gradually decreased in COPD patients ranging from grade 1-2 to 4. Serum 25(OH)D was inversely associated with inflammatory cytokines in COPD patients. Further analysis found that NF-κB and AP-1 signaling were activated in COPD patients. Besides, inflammatory signaling was gradually increased in parallel with the severity of COPD. By contrast, pulmonary nuclear vitamin D receptor was decreased in COPD patients. In vitro experiments showed that 1,25(OH)₂D₃ inhibited LPS-activated inflammatory signaling in A549 cells (human lung adenocarcinoma cell). Mechanically, 1,25(OH)₂D₃ reinforced physical interactions between vitamin D receptor with NF-κB p65 and c-Jun. Our results indicate that vitamin D is inversely correlated with inflammatory signaling in COPD patients. Inflammation may be a vital mediator of COPD progress in patients with low vitamin D levels.

Contemporary Formulation Development for Inhaled Pharmaceuticals

Pulmonary delivery has gained increased interests over the past few decades. For respiratory conditions, targeted drug delivery directly to the site of action can achieve a high local concentration for efficacy with reduced systemic exposure and adverse effects. For systemic conditions, the unique physiology of the lung evolutionarily designed for rapid gaseous exchange presents an entry route for systemic drug delivery. Although the development of inhaled formulations has come a long way over the last few decades, many aspects of it remain to be elucidated. In particular, a reliable and well-understood method for in vitro-in vivo correlations remains to be established. With the rapid and ongoing advancement of technology, there is much potential to better utilise computational methods including different types of modelling and simulation approaches to support inhaled formulation development. This review intends to provide an introduction on some fundamental concepts in pulmonary drug delivery and inhaled formulation development followed by discussions on some challenges and opportunities in the translation of inhaled pharmaceuticals from preclinical studies to clinical development. The review concludes with some recent advancements in modelling and simulation approaches that could play an increasingly important role in modern formulation development of inhaled pharmaceuticals.

Impact of the Local Inflammatory Environment on Mucosal Vitamin D Metabolism and Signaling in Chronic Inflammatory Lung Diseases

Vitamin D plays an active role in the modulation of innate and adaptive immune responses as well as in the protection against respiratory pathogens. Evidence for this immunomodulatory and protective role is derived from observational studies showing an association between vitamin D deficiency, chronic airway diseases and respiratory infections, and is supported by a range of experimental studies using cell culture and animal models. Furthermore, recent intervention studies have now shown that vitamin D supplementation reduces exacerbation rates in vitamin D-deficient patients with chronic obstructive pulmonary disease (COPD) or asthma and decreases the incidence of acute respiratory tract infections. The active vitamin D metabolite, 1,25-dihydroxy-vitamin D (1,25(OH)₂D), is known to contribute to the integrity of the mucosal barrier, promote killing of pathogens (via the induction of antimicrobial peptides), and to modulate inflammation and immune responses. These mechanisms may partly explain its protective role against infections and exacerbations in COPD and asthma patients. The respiratory mucosa is an important site of local 1,25(OH)₂D synthesis, degradation and signaling, a process that can be affected by exposure to inflammatory mediators. As a consequence, mucosal inflammation and other disease-associated factors, as observed in e.g., COPD and asthma, may modulate the protective actions of 1,25(OH)₂D. Here, we discuss the potential consequences of various disease-associated processes such as inflammation and exposure to pathogens and inhaled toxicants on vitamin D metabolism and local responses to 1,25(OH)₂D in both immune- and epithelial cells. We furthermore discuss potential consequences of disturbed local levels of 25(OH)D and 1,25(OH)₂D for chronic lung diseases. Additional insight into the relationship between disease-associated mechanisms and local effects of 1,25(OH)₂D is expected to contribute to the design of future strategies aimed at improving local levels of 1,25(OH)₂D and signaling in chronic inflammatory lung diseases.

The effects of 1α,25-dihydroxyvitamin D3 on alveolar repair and bone mass in adiponectin-deficient mice

Chronic obstructive pulmonary disease (COPD) is a major cause of death worldwide. However, no drugs can regenerate lung tissue in COPD patients, and differentiation-inducing drugs that can effectively treat damaged alveoli are needed. In addition, the presence of systemic comorbidities is also considered problematic. Our previous study revealed that a retinoic acid derivative improved emphysema in elastase-induced COPD model mice at a dose of 1.0 mg/kg, whereas 1α,25-dihydroxyvitamin D3 (1,25(OH)₂D₃) showed an emphysema-improving effect in the same model at 0.1 μg/kg. Elastase-induced COPD model mice do not exhibit a systemic disease state, so evaluation in a model that better reflects the human disease state is considered necessary. To solve this problem, we focused on the adiponectin-deficient mouse and examined the effects of 1,25(OH)₂D₃ on alveolar regeneration. Fifty-week-old adiponectin-deficient mice were treated with 1,25(OH)₂D₃ (0.1 μg/kg) twice a week, for 30 weeks. The effects of pulmonary administration on alveolar repair were evaluated according to the distance between alveolar walls (Lm values) and computed tomography (CT) parameters. Bone density was evaluated based on CT. The administration of 1,25(OH)₂D₃ was confirmed to show a significant therapeutic effect. The Lm values in the control and 1,25(OH)₂D₃-treated groups were 98 ± 4 μm and 63 ± 1 μm, respectively. However, on CT, the average CT value and % of low attenuation area showed no significant change. In adiponectin-deficient mice, the reduction of bone density (cortical, spongy, and total bone), which is a systemic symptom of COPD, was significantly suppressed by 1,25(OH)₂D₃ at 80 weeks of age. The present study suggests that 1,25(OH)₂D₃ could be a potential candidate drug that may provide a radical cure for the lung disease and comorbidities of COPD patients. This work can lead to the development drugs that may provide a radical cure for COPD.

Development of a DNA Vaccine for Melanoma Metastasis by Inhalation Based on an Analysis of Transgene Expression Characteristics of Naked pDNA and a Ternary Complex in Mouse Lung Tissues

The present study investigated a pulmonary delivery system of plasmid DNA (pDNA) and its application to melanoma DNA vaccines. pCMV-Luc, pEGFP-C1, and pZsGreen were used as a model pDNA to evaluate transfection efficacy after inhalation in mice. Naked pDNA and a ternary complex, consisting of pDNA, dendrigraft poly-l-lysine (DGL), and γ-polyglutamic acid (γ-PGA), both showed strong gene expression in the lungs after inhalation. The transgene expression was detected in alveolar macrophage-rich sites by observation using multi-color deep imaging. On the basis of these results, we used pUb-M, which expresses melanoma-related antigens (ubiquitinated murine melanoma gp100 and tyrosinase-related protein 2 (TRP2) peptide epitopes), as DNA vaccine for melanoma. The inhalation of naked pUb-M and its ternary complex significantly inhibited the metastasis of B16-F10 cells, a melanoma cell line, in mice. The levels of the inflammatory cytokines, such as TNF-α, IFN-γ, and IL-6, which enhance Th1 responses, were higher with the pUb-M ternary complex than with naked pUb-M and pEGFP-C1 ternary complex as control. In conclusion, we clarified that the inhalation of naked pDNA as well as its ternary complex are a useful technique for cancer vaccination.

Quantitative comparison of three widely-used pulmonary administration methods in vivo with radiolabeled inhalable nanoparticles

Pulmonary formulations have been attracting much attention because of their direct effects on respiratory diseases, but also their non-invasive administration for the treatment of systemic diseases. When developing such formulations, they are typically first investigated in mice. As there are various pulmonary administration methods, the researcher has to decide on the best quantitative method for their preclinical investigations among candidate methods, both for total delivery and distribution within the lung lobes. In this study, we investigated the deposition and distribution of siRNA loaded PLGA nanoparticles (NPs) in the different lung lobes via three widely used pulmonary administration methods: intratracheal instillation, intratracheal spraying and intranasal instillation. The NPs were radiolabeled with ¹¹¹In, administered and a single photon emission computed tomography (SPECT/CT) whole body scan performed. Quantitative image volume of interest (VOI) analysis of all inhalation related organs was performed, plus sub-organ examinations using dissection and gamma counting. Intratracheal instillation and intratracheal spraying deposited >95% and >85% of radiolabeled NPs in the lung, respectively. However, the lung lobe distribution of the NPs was inhomogeneous. Intranasal instillation deposited only ~28% of the dose in the lungs, with even larger inhomogeneity and individual variation between animals. Furthermore, there was a high deposition of the NPs in the stomach. Intratracheal instillation and intratracheal spraying deposit a large number of NPs in the lungs, and are thus useful to test therapeutic effects in preclinical animal studies. However, the inhomogeneous distribution of formulation between lung lobes needs to be considered in the experimental design. Intranasal instillation should not be used as a means of pulmonary administration.

Gestational vitamin D deficiency impairs fetal lung development through suppressing type II pneumocyte differentiation

Gestational vitamin D deficiency is associated with pulmonary diseases. This study aimed to investigate the effect of gestational vitamin D deficiency on fetal lung development in mice. Absolute and relative weights of fetal lungs were reduced in vitamin D deficient (VDD) group. Incrassate mesenchyme, measured by septal wall thickness, accompanied by lessened saccular space, was shown in VDD group. Numerous immature type II pneumocytes, as determined by PAS staining, were observed in VDD group. Moreover, increased Ki67-positive cells, a marker of cell proliferation, was detected in VDD group. The additional experiments showed that Sftpa, Sftpb, Sftpc and Sftpd, four surfactant genes, were downregulated and pro-surfactant protein B was reduced in VDD group. FoxA1, FoxA2 and TTF-1, three transcription factors that regulate surfactant genes, and VEGF, a key regulator for pulmonary maturation, were downregulated in VDD group. These results suggest that gestational vitamin D deficiency impairs fetal lung development partially through suppressing type II pneumocyte differentiation.

Structural development of non-secosteroidal vitamin D receptor (VDR) ligands without any asymmetric carbon

Non-secosteroidal VDR ligands without any assymmetric carbon were designed and synthesized based on the structure of the previously reported non-secosteroidal VDR agonist LG190178. The VDR-agonistic activity of all synthesized compounds was evaluated, and 7b emerged as a potent agonist activity with an EC₅₀ value of 9.26 nM. Moreover, a docking simulation analysis was also performed to determine the binding mode of 7b with VDR-LBD.

Pulmonary administration of curcumin inhibits B16F10 melanoma lung metastasis and invasion in mice

PURPOSE

Curcumin is expected to have beneficial effects including an anti-cancer effect. However, its lower bioavailability is a critical concern and limits the utility of curcumin in clinical practice. In this study, we investigated whether transpulmonary delivery of curcumin is pharmacologically effective along with improving its bioavailability in mice with lung metastasis.

METHODS

C57BL/6J mice were injected with B16F10 melanoma cells via their tail vein and given curcumin by pulmonary administration every other day. The lung tissue of the vehicle-treated mice on day 17 was covered by nodules of metastatic melanoma.

RESULTS

Pulmonary curcumin administration significantly and dose-dependently protected the lung metastasis of melanoma. The phosphorylation of JNK (c-Jun NH2 terminal kinase) and HLJ1 expression levels in the lung metastatic nodules of the melanoma were significantly increased by pulmonary curcumin administration. The anti-metastatic effect of curcumin was blunted in mice injected with HLJ1 knocked-down B16F10 melanoma. Systemic bioavailability after pulmonary administration was 61-times higher than after oral administration. Additionally, the curcumin concentration in the lung tissue was sustained to a high level until 24 h after pulmonary administration.

CONCLUSIONS

This study showed the usefulness of curcumin to suppress lung metastasis of melanoma by pulmonary administration, a method that may overcome the low-bioavailability of curcumin.

Effect of 4-[(5,6,7,8-Tetrahydro-5,5,8,8-Tetramethyl-2-Naphthalenyl)Carbamoyl]Benzoic Acid (Am80) on Alveolar Regeneration in Adiponectin Deficient-Mice Showing a Chronic Obstructive Pulmonary Disease-Like Pathophysiology

Chronic obstructive pulmonary disease (COPD) is an intractable pulmonary disease that causes widespread and irreversible alveolar collapse. Although COPD occurs worldwide, only symptomatic therapy is currently available. Our objective is the development of therapeutic agents to eradicate COPD. Therefore, we focused on 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl) carbamoyl] benzoic acid (Am80), which is a derivative of all-trans retinoic acid. We evaluated the effects of Am80 on alveolar repair in a novel COPD model of adiponectin-deficient mice. This mouse model has more symptoms similar to human COPD than the classic elastase-induced emphysema mouse model. Lung volume, computed tomography (CT) values, low-attenuation area ratios, and bone and fat mass were measured by CT. However, the administration of Am80 did not affect these results. To examine the degree of destruction in the alveoli, the mean linear intercept of the alveolar walls was calculated, and assessment of this value confirmed that there was a significant difference between the control (46.3 ± 2.3 μm) and 0.5 mg/kg Am80-treated group (34.4 ± 1.7 µm). All mice survived the treatment, which lasted for more than 6 months, and we did not observe any abnormalities in autopsies performed at 80 weeks of age. These results suggested that Am80 was effective as a novel therapeutic compound for the treatment of COPD.