Question

A 53-year-old man, who has been smoking for the past 35 years at a two-pack-a-day rate, visits his physician for a cough that will not go away, and for difficulty in breathing. A chest X-ray rules out cancer, but does display an increased anterior-posterior (AP) diameter, flattened diaphragms, and "air trapping." The patient is told that his condition will not improve, and that he needs to stop smoking to stop the progression of the disease. At the molecular level, this disease is due to which one of the following?

(A) Enhanced trypsin activity in the lung
(B) Decreased trypsin activity in the lung
(C) Enhanced α1-antitrypsin activity in the lung
(D) Decreased α1-antitrypsin activity in the lung
(E) Enhanced reduction of sulfhydryl groups in the lung
(F) Decreased reduction of sulfhydryl groups in the lung

Answer 1

Emphysema is caused by a deficiency in alpha-1 antitrypsin enzyme, which normally inhibits neutrophil elastase. Smoking increases activity of neutrophil elastase and decreases activity of alpha-1 antitrypsin, leading to emphysema.

Step-by-step explanation:

Emphysema is a disease in which the walls of the alveoli in the lungs are destroyed, leading to a decrease in the surface area available for gas exchange. This disease is caused by a deficiency in the enzyme alpha-1 antitrypsin, which normally inhibits the activity of the enzyme neutrophil elastase. The neutrophil elastase can destroy the elastin in the alveoli, resulting in the progression of emphysema. In the case of the 53-year-old man who has been smoking for 35 years, his smoking has contributed to the development of emphysema by increasing the activity of neutrophil elastase and decreasing the activity of alpha-1 antitrypsin.