[Prevention of elderly pneumonia by pneumococcal, influenza and BCG vaccinations].

Pneumonia is a major cause of morbidity and mortality in elderly people, especially in those with chronic medical conditions such as chronic heart and lung diseases. We prospectively examined the effect of influenza and pneumococcal vaccinations on the rate of hospitalization for and complications of pneumonia, all respiratory tract conditions and mortality in elderly bedridden patients and found that both febrile days and pneumonia cases decreased. Thus, these results show that it is valuable to vaccinate for influenza elderly people even if they are confined to bed. Furthermore, the tuberculin skin test is an easy method to check the cell-mediated immunity in the elderly people. In the tuberculin skin test, all Japanese over 65 years old should have positive status. A negative result indicates depressed cell-mediated immunity. We undertook a trial to vaccinate tuberculin negative elderly people with BCG vaccine and found that the risk of pneumonia is decreased to a similar degree to that in subjects with positive tuberculin test results. We conclude that vaccination might be an effective strategy for the prevention of pneumonia in elderly people with limited activities of daily living.

Retinoic acid inhibits elastase-induced injury in human lung epithelial cell lines.

The protective effects of retinoic acid on elastase-induced lung epithelial cell injury were studied using elastase extracted from purulent human sputum, the BEAS-2B human bronchial epithelial cell line, A549 human type II lung cell line, and primary cultures of human tracheal epithelial cells. Elastase decreased viability of BEAS-2B cells, A549 cells, and human tracheal epithelial cells in concentration- and time-dependent fashions. Elastase also induced apoptosis of BEAS-2B cells, A549 cells, and the tracheal epithelial cells detected with cell death detection enzyme-linked immunosorbent assay and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) methods. Retinoic acid alone did not affect the viability of BEAS-2B cells, A549 cells, or the tracheal epithelial cells, and did not induce apoptosis of the cells. However, retinoic acid prevented the decreases in the viability and reduced apoptosis of BEAS-2B cells, A549 cells, and the tracheal epithelial cells induced by elastase. Likewise, retinoic acid inhibited caspase 3 activity in BEAS-2B cells and A549 cells induced by elastase, as well as proteolytic activity of elastase. Furthermore, caspase 3 inhibitor inhibited the elastase-induced apoptosis of the cells. These findings suggest that retinoic acid may inhibit elastase-induced lung epithelial cell injury partly through the inhibition of proteolytic activity of elastase and through the inhibition of caspase 3 activity by elastase. Retinoic acid may, therefore, have protective effects against the elastase-induced lung injury and subsequent development of pulmonary emphysema.