Fibroblast mitogenic activity of lung lavage fluid from infants with chronic lung disease of prematurity.

BACKGROUND

Lung fibrosis is thought to be important in chronic lung disease of prematurity (CLD).

METHODS

Fibroblast proliferative activity was assessed in 207 bronchoalveolar lavage fluid (BALF) samples from 43 infants. Sixteen developed CLD (birth weight 765 g (630-1230), gestation 26.5 weeks (23-29)), 18 developed respiratory distress syndrome (RDS) (birth weight 1415 g (430-4160), gestation 31 weeks (23-39)), and nine control infants (birth weight 2110 g (900-3720), gestation 32 weeks (26-41)) received mechanical ventilation for non-pulmonary reasons.

RESULTS

The fibroblast proliferative activity relative to 10% fetal calf serum was 64-75% in infants with CLD, 55-86% in the RDS group, and 42-68% in control infants during the first 5 weeks of life. Only at day 3 was there a difference between the groups (CLD 72% v control 42%, p < 0.01; RDS 63% v control 42%, p < 0.05). With the use of neutralising antibodies, platelet derived growth factor BB (PDGF-BB) and epidermal growth factor were undetectable, and insulin-like growth factor I (IGF-I) accounted for 14% (p < 0.05) and 11% (p < 0.005) of BALF mitogenic activity from the RDS and CLD groups respectively.

CONCLUSIONS

The mitogenic activity of BALF was similar in the three groups studied and was only partially accounted for by IGF-I. Growth factors other than PDGF-BB and IGF-I contribute significantly to this process.