Different subsets of circulating angiogenic cells do not predict bronchopulmonary dysplasia or other diseases of prematurity in preterm infants

Cellular and humoral biomarkers of Bronchopulmonary Dysplasia

The pathogenesis of Bronchopulmonary Dysplasia (BPD) is multifactorial and the clinical phenotype of BPD is extremely variable. Predicting BPD is difficult, as it is a disease with a clinical operational definition but many clinical phenotypes and endotypes. Most biomarkers studied over the years have low predictive accuracy, and none are currently used in routine clinical care or shown to be useful for predicting longer-term respiratory outcome. Targeted cellular and humoral biomarkers and novel systems biology 'omic' based approaches including genomic and microbiomic analyses are described in this review.

Endothelial Progenitor Cells as Prognostic Markers of Preterm Birth-Associated Complications

Preterm birth is associated with alteration of the vascular tree that can result in disease states such as bronchopulmonary dysplasia and retinopathy of prematurity during the neonatal period and emphysema and hypertension in adulthood. Studies have suggested a potential role for endothelial progenitor cells in the pathophysiology of prematurity-related complications involving blood vessels; however, this knowledge has never been synthesized. We conducted a systematic review of the published data to examine the characteristics of endothelial progenitor cells in relation to preterm birth in humans. Preterm infants compared with term controls displayed similar or increased circulating/cord blood endothelial progenitor cell counts. However, the preterm endothelial progenitor cells were more vulnerable to exogenous factors such as oxidative stress. A reduced number, in particular of endothelial colony-forming cells, was associated with bronchopulmonary dysplasia. No studies have examined endothelial progenitor cells beyond the neonatal period. These findings could prove useful in the identification of biomarkers for prognostication or therapeutic strategies for vascular-related diseases in preterm-born individuals. Stem Cells Translational Medicine 2017;6:7-13.

Lung parenchymal development in premature infants without bronchopulmonary dysplasia

RATIONALE

While infants who are born extremely premature and develop bronchopulmonary dysplasia (BPD) have impaired alveolar development and decreased pulmonary diffusion (DLCO), it remains unclear whether infants born less premature and do not develop BPD, healthy premature (HP), have impaired parenchymal development. In addition, there is increasing evidence that pro-angiogenic cells are important for vascular development; however, there is little information on the relationship of pro-angiogenic cells to lung growth and development in infants.

OBJECTIVE

and Methods Determine among healthy premature (HP) and fullterm (FT) infants, whether DLCO and alveolar volume (VA) are related to gestational age at birth (GA), respiratory support during the neonatal period (mechanical ventilation [MV], supplemental oxygen [O2], continuous positive airway pressure [CPAP]), and pro-angiogenic circulating hematopoietic stem/progenitor cells (CHSPCs). We measured DLCO, VA, and CHSPCs in infants between 3-33 months corrected-ages; HP (mean GA = 31.7 wks; N = 48,) and FT (mean GA = 39.3 wks; N =88).

RESULT

DLCO was significantly higher in HP than FT subjects, while there was no difference in VA , after adjusting for body length, gender, and race. DLCO and VA were not associated with GA, MV and O2; however, higher values were associated with higher CHSPCs, as well as treatment with CPAP.

CONCLUSION

Our findings suggest that in the absence of extreme premature birth, as well as BPD, prematurity per se, does not impair lung parenchymal development.

Impaired pulmonary vascular development in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD), the chronic lung disease associated with preterm birth, results from the disruption of normal pulmonary vascular and alveolar growth. Though BPD was once described as primarily due to postnatal injury from mechanical ventilation and oxygen therapy after preterm birth, it is increasingly appreciated that BPD results from antenatal and perinatal factors that interrupt lung development in infants born at the extremes of prematurity. The lung in BPD consists of a simplified parenchymal architecture that limits gas exchange and leads to increased cardiopulmonary morbidity and mortality. This review outlines recent advances in the understanding of pulmonary vascular development and describes how the disruption of these mechanisms results in BPD. We point to future therapies that may augment postnatal vascular growth to prevent and treat this severe chronic lung disease.