Effects of ageing and smoking on SP-A and SP-D levels in bronchoalveolar lavage fluid

Tomoko Betsuyaku, Y. Kuroki, K. Nagai, Y. Nasuhara, M. Nishimura

Research output: Contribution to journalArticlepeer-review

92 Citations (Scopus)


Surfactant protein (SP)-A and SP-D are collagen-like glycoproteins that are synthesized in the distal pulmonary epithelium. This study examined the effects of ageing and long-term smoking on SP-A and SP-D in the lungs. The possible links to the development of pulmonary emphysema were also investigated. Sequential lavage was performed in young and middle-aged or elderly nonsmokers and asymptomatic current smokers with various smoking histories. Middle-aged or elderly smokers were further categorised according to the presence of emphysema by high-resolution computed tomography. Levels of SP-A and SP-D in bronchial lavage (BL) fluid and in bronchoalveolar lavage (BAL) fluid were quantified by ELISA. Significant decreases in SP-A were seen with age in nonsmokers in BL fluid, but not in BAL fluid. Middle-aged or elderly smokers with emphysema had lower levels of SP-A in both BL and BAL fluids when compared with young subjects, and in BL fluid when compared with middle-aged or elderly smokers without emphysema. SP-D did not change with age alone, however, it was decreased in middle-aged or elderly smokers when compared with similarly aged nonsmokers. In conclusion, surfactant protein-A may decrease with age alone or due to the cumulative effects of long-term smoking and development of emphysema, while surfactant protein-D decreases due to long-term smoking.

Original languageEnglish
Pages (from-to)964-970
Number of pages7
JournalEuropean Respiratory Journal
Issue number6
Publication statusPublished - 2004 Dec
Externally publishedYes


  • Ageing
  • Chronic obstructive pulmonary disease
  • Collectin
  • Pulmonary mephysema
  • Sequential bronchoalveolar lavage
  • Smoking

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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