Prematurity predisposes to cardiovascular disease; however the underlying mechanisms remain
elusive. Disturbance of the endothelial glycocalyx (EG), an important regulator of vessel function,
is thought to contribute to vascular pathology. Here, we studied the EG with respect to gestational
and postnatal age in preterm and term neonates. The Perfused Boundary Region (PBR), an inverse
measure of glycocalyx thickness, was measured postnatally in 85 term and 39 preterm neonates.
Preterm neonates were further analyzed in two subgroups i.e., neonates born < 30 weeks gestational age (group A) and neonates born ≥ 30 weeks (group B). In preterm neonates, weekly follow‑up measurements were performed if possible. PBR differed significantly between preterm and term neonates with lowest values representing largest EG dimension in extremely premature infants possibly reflecting its importance in fetal vascular development. Linear regression revealed a dependence of PBR on both, gestational age and postnatal age. Furthermore, hematocrit predicted longitudinal PBR changes. PBR measured in group A at a corrected age of > 30 weeks was significantly
higher than in group B at birth, pointing towards an alteration of intrinsic maturational effects by
extrinsic factors. These changes might contribute to the increased cardiovascular risk associated with