Isolation of tracheal aspirate mesenchymal stromal cells predicts bronchopulmonary dysplasia.

Background: We have isolated mesenchymal stem cells (MSCs) from tracheal aspirates of premature infants with respiratory distress. Under the influence of transforming growth factor β, MSCs differentiate into α-smooth-muscle actin-expressing myofibroblasts. Myofibroblasts are increased in the lungs of patients with bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurely born infants.
Objective: We tested whether isolation of MSCs from tracheal aspirates of premature infants with respiratory distress during the first week of life correlates with BPD.
Methods: Eighty-four infants born at a gestational age of <33 weeks and requiring mechanical ventilation were studied. Aspirates were collected during suctioning and centrifuged. Cell pellets were resuspended in culture medium and plated. Adherent cells were grown to confluence.
Results: MSCs were isolated from the tracheal aspirates of 56 infants; 28 aspirate samples showed no MSCs. There was no statistical difference in gestational age or birth weight between the MSC and no-MSC groups. In the MSC group, 12 infants died and 25 developed BPD, as defined by a requirement for supplemental oxygen at 36 weeks' postmenstrual age. In the no-MSC group, 6 infants died and 1 developed BPD. Accounting for potential influences of gender, birth weight, gestational age, number of tracheal aspirate samples taken, and the duration of endotracheal intubation (up to 7 days), isolation of MSCs increased the adjusted odds ratio of BPD more than 21-fold (95% confidence interval: 1.82-265.85).
Conclusions: Isolation of tracheal aspirate MSCs predicts the development of BPD, which suggests that MSCs play an important role in the pathogenesis of this disease.