Plasma fibronectin levels in extremely preterm infants in the first 8 weeks of life

Abstract Fibronectin has in the past been considered to function simply as a non‐specific plasma opsonin. However, recent studies have demonstrated that this molecule plays an important role in fundamental components of the immune response, for example, neutrophil adhesion, T cell activation and endothelial function. Additionally, fibronectin is important in lung homeostasis where it contributes to alveolar epithelial integrity. In this study plasma fibronectin levels were measured longitudinally in a group of extremely preterm infants, mean gestational age 27 weeks. Plasma fibronectin levels at birth were significantly lower in the preterm study group than in term controls (mean 91±33 μg/mL compared with 214±62 μg/mL in the term controls, P<0.0001). The preterm cohort demonstrated a more than two‐fold rise in plasma fibronectin on days one and two; levels fell almost to baseline values by day three with a subsequent slow rise to a plateau by day 28. No further increase was seen by day 56. This sequence of early changes in fibronectin levels mirrored closely the time course of respiratory distress syndrome. Infants of mothers with pre‐eclampsia had significantly lower peak fibronectin levels than in those without (P= 0.016), and those infants with bronchopulmonary dysplasia showed a trend towards lower basal fibronectin levels (P= 0.07) and a greater difference between peak and basal levels (P= 0.05). Neonates, particularly those born preterm, have blunted immunological responses to infection. Fibronectin plays a key role in immunological responsiveness. The significant changes in fibronectin levels after birth in the preterm neonate are likely to have important pathophysiological consequences. The relationship between alterations in fibronectin after birth, endothelial and epithelial cell function, and respiratory distress syndrome (RDS) remain to be explored.