NF-kappaB in tracheal lavage fluid from intubated premature infants: association with inflammation, oxygen, and outcome.

OBJECTIVES

To determine if tracheal lavage concentrations of the transcription factor NF-kappaB, which is activated by risk factors associated with bronchopulmonary dysplasia (BPD) and induces expression of cytokines associated with BPD, is related to BPD in premature infants.

DESIGN

Serial tracheal lavage samples from intubated premature infants were analysed for cell count and concentrations of interleukin (IL)8 and NF-kappaB, corrected for dilution by secretory component concentrations.

SETTING

Level III university hospital neonatal intensive care unit.

PATIENTS

Thirty three intubated infants (mean (SD) birth weight 903 (258) g, median gestation 27 weeks (range 24-31)) in the first 14 days of life.

MAIN OUTCOME MEASURES

Tracheal effluent NF-kappaB, IL8, and cell counts, corrected for dilution by secretory component measurement.

RESULTS

Square root transformed NF-kappaB concentrations were significantly related to signs of inflammation (cell count, p = 0.002; IL8, p = 0.019) and to simultaneous fraction of inspired oxygen in samples from the first 3 days of life (r = 0.512, p<0.003). Of the 32 subjects with samples in the first 3 days of life, the half who either died or had BPD had higher NF-kappaB concentrations than those without BPD (square root concentration 0.097 (0.043) v 0.062 (0.036) microg/microg protein/microg secretory component, p = 0.018).

CONCLUSIONS

Tracheobronchial lavage NF-kappaB concentrations are related to lung inflammation, oxygen exposure, and pulmonary outcome in intubated preterm infants. NF-kappaB activation may be an early critical step leading to BPD.