Endothelial colony forming cell administration promotes neurovascular unit development in growth restricted and appropriately grown fetal lambs

Abstract

Background Fetal growth restriction (FGR) is associated with deficits in the developing brain, including neurovascular unit (NVU) dysfunction. Endothelial colony forming cells (ECFC) can mediate improved vascular stability, and have demonstrated potential to enhance vascular development and protection. This investigation examined whether ECFCs from human umbilical cord blood (UCB) enhanced NVU development in FGR and appropriate for gestational age (AGA) fetal sheep. Methods Twin-bearing ewes had surgery performed at 88–90 days’ gestation, inducing FGR in one fetus. At 113 days, ECFCs (1 × 107 cells) cultured from human UCB were administered intravenously to fetal sheep in utero. At 127 days, ewes and their fetuses were euthanised, fetal brains collected, and NVU components analysed by immunohistochemistry. Results Twenty-four fetal lambs, arranged in four groups: AGA (n = 7), FGR (n = 5), AGA + ECFC (n = 6), and FGR + ECFC (n = 6), were included in analyses. FGR resulted in lower body weight than AGA (P = 0.002) with higher brain/body weight ratio (P = 0.003). ECFC treatment was associated with increased vascular density throughout the brain in both AGA + ECFC and FGR + ECFC groups, as well as increased vascular–astrocyte coverage and VEGF expression in the cortex (P = 0.003, P = 0.0006, respectively) and in the subcortical white matter (P = 0.01, P = 0.0002, respectively) when compared with the untreated groups. Conclusions ECFC administration enhanced development of NVU components in both the AGA and FGR fetal brain. Further investigation is required to assess how to optimise the enhanced angiogenic capabilities of ECFCs to provide a therapeutic strategy to protect the developing NVU against vulnerabilities associated with FGR.

Effects of fetal growth restriction on the perinatal neurovascular unit and possible treatment targets

“…A recent investigation found ECFC treatment enhanced NVU development across several domains in both AGA and FGR fetal lambs. 113 ECFCs used in this study were derived from human UCB and administered intravenously to preterm fetal lambs in utero, with results providing evidence to support the vasculogenic capacity of the cells in the perinatal brain. In particular, ECFC administration was associated with increased vascular density, an effect that was largely attributable to increased vessel sizes.…”

“…In particular, ECFC administration was associated with increased vascular density, an effect that was largely attributable to increased vessel sizes. 113 This outcome was seen in both AGA and FGR preterm fetal lambs, occurring throughout each of the grey and white matter regions investigated. ECFC administration also led to increases in vascular astrocyte coverage and angiogenic signalling within cortical grey matter and SCWM, reinforcing the potential of ECFC-based treatments in enhancing perinatal NVU development and protection.…”

“…3 ). The lamb trials exploring UCBC and ECFC treatment study early onset FGR, 45 , 113 induced at 88 days gestation, which correlates to 25 weeks in human pregnancies while the lamb trial exploring MLT treatment induced FGR at 105 days gestation, which correlates closer to late-onset FGR in humans. 44 It is worth noting that the piglets being trialled did not have surgically induced FGR, which means no data regarding the timing of FGR onset is available from piglets.…”

“…ECFC administration also led to increases in vascular astrocyte coverage and angiogenic signalling within cortical grey matter and SCWM, reinforcing the potential of ECFC-based treatments in enhancing perinatal NVU development and protection. 113 …”

The Temporal Relationship between Blood–Brain Barrier Integrity and Microglial Response following Neonatal Hypoxia Ischemia

“…Glucose transporters (Glut1+ staining), astrocytes (GFAP+), tight-junction markers (claudin-5), and basal lamina (laminin+) staining density in the somatosensory cortex were analyzed using QuPath and Image J software, as described previously [19,20]. Density was averaged between selected regions of interest per animal, and a mean was calculated for each animal.…”