Defense Date


Document Type


Degree Name

Doctor of Philosophy


Pharmaceutical Sciences

First Advisor

Masahiro Sakagami


Pulmonary emphysema is a serious worldwide illness, causing progressive and irreversible alveolar wall loss and difficulty in breathing. It is caused mostly by cigarette smoking. However, its unresolved complex and multiple pathogenic mechanisms have left this disease without effective pharmacotherapy. This project hypothesized that cinnamic acid-based dehydropolymers (DHPs), originally discovered as novel anti-coagulants, protect against emphysema through their potent triple inhibitory actions against oxidative stress, inflammation and elastase, some of the pathogenic mechanisms associated with this disease. Three in vitro inhibitory activity assays for oxidative stress, lung inflammation and neutrophil elastase (NE) were developed and used to identify the most potent triple inhibitor DHP. These activities were determined by chromogenic free radical generation in chemical oxidation, lung epithelial (Calu-3) repression of pro-inflammatory nuclear factor κB (NFκB) upon its plasmid transfection and chromogenic substrate NE hydrolysis, respectively. The sulfated caffeic acid DHP, CDS was shown to be the most potent in all three assessments, yielding the half-maximal inhibitory concentrations of 3.52, ~10 and 0.43 µM, respectively. CDS was tested with pulmonary delivery in an in vivo rat model of emphysema induced by elastase and cigarette smoke extract (HSE/CSE). CDS at 5 and 30 μg/kg was instilled into the lung at 2 h prior to HSE/CSE instillation. The lung tissues and bronchoalveolar lavage fluids (BALFs) were taken 1 or 48 h post-HSE/CSE instillation to determine the tissue reduced glutathione (rGSH), airway infiltration of inflammatory neutrophils and airway luminal elastase alongside lung hemorrhage. The HSE/CSE instillation significantly caused 43.0 % decrease in rGSH, 104.8-fold greater neutrophil infiltration, 2.8-fold higher elastase activity and 9.3-fold increased lung hemorrhage, compared to the saline (negative) control. However, all these inductions were significantly protected by CDS at 30 μg/kg, exhibiting 92.9, 76.6, 59.7 and 70.4 % inhibition, respectively; reduced effects were seen at 5 μg/kg, showing its dose-related responses. As a result, the HSE/CSE-induced airspace enlargement assessed on 28th day was also prevented by CDS at 30 μg/kg, yet not at 5 μg/kg. In conclusion, this study has demonstrated the in vitro and in vivo effectiveness of CDS for its possible use in the protection against emphysema development, specifically via inhalation.


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