Impact of resveratrol‐mediated increase in uterine artery blood flow on fetal haemodynamics, blood pressure and oxygenation in sheep

Abstract

High placental vascular resistance hinders uterine artery (UtA) blood flow and fetal substrate delivery. In the same group of animals as the present study, we have previously shown that resveratrol (RSV) increases UtA blood flow, fetal weight and oxygenation in an ovine model of human pregnancy. However, the mechanisms behind changes in growth and the effects of increases in UtA blood flow on fetal circulatory physiology have yet to be investigated. Twin-bearing ewes received s.c. vehicle (VEH, n = 5) or RSV (n = 6) delivery systems at 113 days of gestation (term = 150 days).Magnetic resonance imaging was performed at 123−124 days to quantify fetal volume, blood flow and oxygen saturation of major fetal vessels. At 128 days, i.v. infusions of sodium nitroprusside and phenylephrine were administered to study the vascular tone of the fetal descending aorta. Maternal RSV increased fetal body volume (P = 0.0075) and weight (P = 0.0358), with no change in brain volume or brain weight. There was a positive relationship between absolute UtA blood flow and umbilical vein oxygen saturation, absolute fetal oxygen delivery and combined fetal twin volume (all P ≤ 0.05).There were no differences between groups in fetal haemodynamics or blood pressure regulation except for higher blood flow to the lower body in RSV fetuses (P = 0.0170).

Placental MRI Predicts Fetal Oxygenation and Growth Rates in Sheep and Human Pregnancy

“…A 3D steady‐state free procession of the uterus ( T E = 1.6 ms; repetition time [ TR ] = 3.38 ms; slice thickness = 2 mm; number of slices = 100–120; number of averages = 1; matrix size = 272 × 272; field of view (FOV) = 430 × 430 mm; average acquisition time ≈9 min) was acquired and segmented using ITK‐SNAP (version 3.8) to measure fetal volume. [ 71 ] Overall fetal volume and brain volume were used to estimate both fetal weight and brain weight using a previously described conversion factor. [ 72 ]…”

Impact of the Addition of a Centrifugal Pump in a Preterm Miniature Pig Model of the Artificial Placenta

“…Nevertheless, it seems likely that the fetal deterioration we observed on both pumped and pumpless AP circuits was more likely to be a consequence of abnormal cardiac loading than fetal hyperglycemia. Although we observed no change in lactate between controls and animals on the AP, it should be noted that both glucose and lactate are higher in pigs than sheep fetuses (Darby et al, 2019(Darby et al, , 2021Aujla et al, 2021;Charest-Pekeski et al, 2021;Schrauben et al, 2021). Mean blood pressure in the UV is 6-8 mmHg in near-term sheep and human fetuses (Rudolph, 2009;Acharya et al, 2016).…”

Acute-on-chronic: using magnetic resonance imaging to disentangle the haemodynamic responses to acute and chronic fetal hypoxaemia

“…A three-dimensional steady-state free procession of the uterus ( T E = 1.45 ms; repetition time (TR) = 3.38 ms; flip angle: 35 deg; in-plane resolution: 1.5 × 1.5 mm; slice thickness = 2 mm; number of slices = 100–120; number of averages = 1; base resolution: 272; FOV = 400 mm; average acquisition time 4–5 min) was acquired and segmented using ITK-SNAP (version 3.8 ( 60 )) to measure fetal and brain volumes ( 39 ). Fetal and brain volumes were used to estimate fetal and brain weights using previously described tissue specific conversion factors ( 61 , 62 ).…”