Fetal growth restriction induces heterogeneous effects on vascular biomechanical and functional properties in guinea pigs (Cavia porcellus)

Abstract

Aim: Fetal growth restriction (FGR) is associated with a variety of cardiometabolicdiseases in adulthood which could involve remodeling processes of the vascular wallsthat could start in the fetal period. However, there is no consensus whether thisremodeling affects in a similar way the whole vascular system.We aimed to determine theeffects of FGR on the vasoactive and biomechanical properties of umbilical and systemicvessels in fetal guinea pigs.Methods: FGR was induced by implanting ameroid occluders atmid-gestation in uterinearteries of pregnant guinea pigs, whilst the control group was exposed to simulatedsurgery. At the term of gestation, systemic arteries (aorta, carotid and femoral) andumbilical vessels were isolated to determine ex vivo contractile and biomechanicalresponses (stretch-stress until rupture) on a wire myograph, as well as opening angleand residual stresses. Histological characteristics in tissue samples were measured byvan Gieson staining.Results: Aorta and femoral arteries from FGR showed an increased in biomechanicalmarkers of stiffness (p < 0.01), contractile capacity (p < 0.05) and relative mediathickness (p < 0.01), but a reduced internal diameter (p < 0.001), compared withcontrols. There were no differences in the biomechanical properties of carotid andumbilical from control and FGR fetuses, but FGR umbilical arteries had a decreasedcontractile response to KCl (p < 0.05) along with a reduced relative media thickness(p < 0.05).Conclusion: Altogether, these changes in functional, mechanical and morphologicalproperties suggest that FGR is associated with a heterogeneous pro-constrictive vascular remodeling affecting mainly the lower body fetal arteries. These effects wouldbe set during a pathologic pregnancy in order to sustain the fetal blood redistributionin the FGR and may persist up to adulthood increasing the risk of a cardiovasculardisease.