Infants With Bronchopulmonary Dysplasia Have Fewer Pro-Angiogenic Circulating Progenitor Cells And Decreased Pulmonary Diffusion RS Tepper, C Tiller, J Mund, J Case, DA Ingram Divisions of Pediatric Pulmonology and Neonatology, Wells Center for Pediatric Research, Riley Children’s Hospital, Indiana University School of Medicine.

Premature Birth and new BPD

Role of Vasculature in BPD Abman et al., AJRCCM 2007

Pulmonary Diffusion Capacity/Alveolar Volume (DLCO/VA) Balinotti et al AJRCCM 2010

Endothelial colony-forming cells (ECFC) and BPD Endothelial colony-forming cells (ECFC) assessed from cord blood are low at extremely low gestational ages and increase with increasing gestation; extremely preterm infants who display lower numbers of ECFC at birth have an increased risk of developing BPD. Borghesi et al. AJRCCM 2009

Capillary Vessel Formation In human studies we have identified primitive pro-angiogenic myeloid cells, which are defined as circulating progenitor cells (CPCs). Co-culture of CPCs with pulmonary endothelial cells accelerates blood vessel formation in vitro. Endothelial Colony Forming Cells Endothelial Colony Forming Cells + Circulating Progenitor Cells (CPC)

HYPOTHESIS Infants and toddlers who were born prematurely have fewer CPCs and lower pulmonary diffusing capacity compared to subjects born fullterm. In addition, fewer CPCs are associated with lower pulmonary diffusing capacity.

Methods: Pulmonary Diffusing Capacity (DLCO) and Alveolar Volume (VA): Following chloral hydrate sedation, measurements were obtained using single breath-hold maneuver at elevated lung volume (airway pressure of 30 cmH2O) with a test gas containing 0.3% CO and 4% He. (Castillo et al Peds Pulm 2006). Circulating Progenitor Cells: 2 ml. of blood were obtained for 5-color polychromatic flow cytometry of mononuclear cells using antibodies directed against cell surface antigens, CD34, CD133, CD31, and CD45, as well as a viability marker, CD41a, and glycophorin A for the exclusion of dead cells, platelets, and red blood cells, respectively. The frequency of CPCs was analyzed using an LSR II flow cytometer and FlowJo software. (Estes et al. Cytometry 2010).

SUBJECTS Fullterm Premature without BPD Premature with BPD P value Number of Subjects 13 8 23 Gestational Age @ birth (weeks) 39.4 31.8 26.0 < 0.001 Age - corrected at Testing (months) 12.4 12.0 13.7 NS Length at Testing (cm) 72.6 73.5 74.2 Mechanical Ventilation (days) - 0.8 21.4 Oxygen (days) 5.1 44.2 CPAP (days) 1.5 15.7

Circulating Progenitor Cells Born Fullterm Born Premature with BPD

Circulating Progenitor Cells

Circulating Progenitor Cells vs. GA

Alveolar Volume

Alveolar Volume (VA ) VA P value Length (cm) < 0.0001 Fullterm Premature Non-BPD Premature BPD 0.747 CPC/nonCPC 0.958

Pulmonary Diffusion Capacity/Alveolar Volume DLCO/VA

Circulating Progenitor Cells and DLCO/VA

CONCLUSIONS Speculation Our findings suggest that infants and toddlers who were born prematurely have fewer CPCs and lower pulmonary diffusing capacity compared to subjects born fullterm. In addition, fewer CPCs are associated with lower pulmonary diffusing capacity. Speculation Increasing the number of CPC early in life may promote vascular development of the lung parenchyma in infants born extremely premature.