ABSTRACT
Chronic obstructive pulmonary disease (COPD) and bronchial asthma are the most common inflammatory lung diseases and share various clinical manifestations in terms of their pathophysiology and treatment. Oxidative stress attracts increasing attention in aging, inflammatory diseases including COPD and asthma. The role of oxidative stress was investigated by the administration of tomato juice containing plenty of lycopene, a carotenoid with a powerful antioxidant activity. To investigate COPD, the senescence-accelerated mouse 476(Sam) was used. This is a naturally occurring animal model for accelerated aging after normal development and maturation. The SAMP1 strain shows age-related structural and functional changes in the lung and is considered to be a mouse model of the senile lung. Aging of the lung is postulated to be an important intrinsic process for the development of emphysema so that even a short period of cigarette smoke exposure may be able to generate emphysema in SAMP1 mice. When SAMP1 mice were exposed to cigarette smoke for 8 wk from the age of 12 to 20 wk, the mean liner intercepts (MLI) and destructive index (DI) of the lung were significantly increased (control air vs. smoke (mean ± SEM); MLI, 68.8 ± 0.7 vs. 75.3 ± 1.7 mm, p < 0.05 and DI, 8.6 ± 0.4 vs. 16.2 ± 1.5%, p < 0.05), whereas no significant changes were observed in SAMR1, control mice that show normal aging. In contrast, smoke-induced emphysema was completely prevented by concomitant ingestion of lycopene given as tomato juice (MLI: smoke with or without lycopene (mean ± SEM), 62.9 ± 0.8 vs. 66.9 ± 1.3 µm, p < 0.05). Smoke exposure increased the apoptosis of the airway and alveolar septal cells and reduced vascular endothelial cell growth factor (VEGF) in lung tissues, but tomato juice ingestion significantly reduced apoptosis and increased the tissue VEGF level. SAMP1 is a useful model for cigarette smoke-induced emphysema and a valuable tool to explore how aging influences the development of lung diseases, and both pathophysiologic mechanisms and the effect of therapeutic intervention on smoke-induced emphysema.
The antioxidative state was analyzed in both healthy subjects and asthma patients by determining the serum concentration of carotenoids. The results demonstrated that the serum lycopene concentration was significantly lower in asthma patients than in healthy subjects. On the other hand, no significant difference has been detected in other carotenoid concentrations. Accordingly, an additional study was conducted in patients with asthma who continued to take tomato juice every day for 12 mon to evaluate its effect on peak flow rate (PEFR), daily variation of PEFR, daily symptoms, and quality of life. After a year of daily tomato juice ingestion, the best PEFR value increased from 352 ± 19 to 399 ± 21 (L/min) after 12 mon (p < 0.01). Decrease of the daily variation of PEFR value was also observed (p < 0.01). Atopic patients with asthma responded better than non-atopic patients. Most patients had a positive impression on daily tomato juice intake since asthma patients realized the improvements of quality of life and asthmatic symptoms. No obvious adverse effect was observed throughout the study. Although the precise mechanism(s) and the active ingredient(s) responsible for these results must be elucidated in detail, the daily intake of tomato juice could therefore be a new candidate of controller for asthma patients.
