Which metal is associated with destruction of type 1 alveolar epithelial cells in the lungs and increased resistance to certain bacterial infections?

Which metal is associated with destruction of type 1 alveolar epithelial cells in the lungs and increased resistance to certain bacterial infections?

• A. Cadmium
• B. Lead
• C. Mercury
• D. Arsenic

Answer: (A)

Cadmium inhalation is a classic cause of toxic lung injury. It directly affects the alveolar lining, with type I alveolar epithelial cells (the thin, gas-exchange surface) being particularly susceptible. When these cells are damaged or destroyed, the alveolar–capillary barrier loses integrity, fluid leaks into the air spaces, and gas exchange becomes impaired—leading to pulmonary edema and diffuse alveolar damage. Cadmium exposure also disrupts local immune defenses in the lung, including alveolar macrophage function, which can alter how the lung responds to inhaled bacteria. In some contexts, this immune modulation has been described as changes in resistance to certain bacterial infections, but the overall effect of cadmium tends to impair host defense rather than reliably increase resistance. Among the metals listed, cadmium is the one most strongly linked to injury of the alveolar type I cells, whereas lead, mercury, and arsenic primarily affect other organs or systems (nervous system, kidneys, carcinogenic and systemic effects) rather than causing targeted destruction of the type I pneumocytes.

Cadmium inhalation is a classic cause of toxic lung injury. It directly affects the alveolar lining, with type I alveolar epithelial cells (the thin, gas-exchange surface) being particularly susceptible. When these cells are damaged or destroyed, the alveolar–capillary barrier loses integrity, fluid leaks into the air spaces, and gas exchange becomes impaired—leading to pulmonary edema and diffuse alveolar damage. Cadmium exposure also disrupts local immune defenses in the lung, including alveolar macrophage function, which can alter how the lung responds to inhaled bacteria. In some contexts, this immune modulation has been described as changes in resistance to certain bacterial infections, but the overall effect of cadmium tends to impair host defense rather than reliably increase resistance. Among the metals listed, cadmium is the one most strongly linked to injury of the alveolar type I cells, whereas lead, mercury, and arsenic primarily affect other organs or systems (nervous system, kidneys, carcinogenic and systemic effects) rather than causing targeted destruction of the type I pneumocytes.