Isolation of Tracheal Aspirate Mesenchymal Stromal Cells Predicts Bronchopulmonary Dysplasia

Abstract

Background We have isolated mesenchymal stromal 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. Patients and Methods Eighty-four infants born at gestational age <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 infants 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 died and 25 developed BPD, as defined by a requirement for supplemental O2 at 36 wks post-menstrual age. In the ‘no MSC’ group, 6 infants died and 1 developed BPD. Accounting for the 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 over 21-fold (95% confidence intervals: 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.

Mesenchymal Stromal Cells from Neonatal Tracheal Aspirates Demonstrate a Pattern of Lung-Specific Gene Expression

“…Thin black lines signify 1.5-fold change based on average probe signal. BPD at a significantly higher rate than patients from whom these cells were not isolated [9]. In the present study, study subjects again demonstrated a high prevalence of BPD; 60% developed BPD, compared with the reported 25% of very low birth weight premature infants [1].…”

“…Our laboratory has previously isolated plastic-adherent, fibroblast-like cells from the tracheal aspirates of premature infants undergoing mechanical ventilation for respiratory distress [7][8][9]. These cells possess colony-forming potential, surface markers, and differentiation potential typically found in mesenchymal stem cells.…”

“…Since we have not thoroughly tested the clonogenicity or in vivo self-renewal of neonatal lung mesenchymal cells, we now refer to them as MSCs, which have a more restricted differentiation potential. Patients from whom MSCs are isolated require more days of mechanical ventilation and supplemental oxygen, and are more likely to develop BPD, than patients from whom these cells are not isolated [7,9]. MSCs differentiate to myofibroblasts in vitro [8].…”

“…We hypothesized that MSCs isolated from neonatal lungs express specific genes indicative of a lung origin. Further, based on the association of neonatal lung MSCs with adverse clinical outcomes [7,9], we hypothesized that, compared with structural lung mesenchymal cells, neonatal lung MSCs possess a pro-inflammatory phenotype. To address these hypotheses, we compared the gene expression pattern of neonatal lung MSCs to cord blood MSCs and diploid fetal and neonatal lung fibroblasts.…”

Pulmonary Hypertension in Preterm Infants with Bronchopulmonary Dysplasia

“…[55][56][57][58] However, airway-derived MSCs are increased in BPD, suggesting that the tissue of origin (e.g., blood, vascular endothelial wall, bone marrow, airway epithelium) plays a critical and yet undefined role in the pathogenesis of BPD. 59 Further studies are needed to describe more clearly how progenitor cell-mediated vasculogenesis is disrupted to cause PVD in BPD and whether progenitor cell therapy will prevent or treat cardiopulmonary disease in preterm infants. Small clinical trials with the most severely affected neonates are the most likely setting in which such novel therapies will be translated into clinical practice.…”