1. Effects of Maternal Sildenafil Treatment on Vascular Function in Growth-Restricted Fetal Sheep.
- Author
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Inocencio IM, Polglase GR, Miller SL, Sehgal A, Sutherland A, Mihelakis J, Li A, and Allison BJ
- Subjects
- Acetylcholine pharmacology, Animals, Birth Weight drug effects, Brain drug effects, Brain embryology, Cardiac Output drug effects, Cerebrovascular Circulation drug effects, Female, Fetal Blood chemistry, Fetal Development drug effects, Fetal Growth Retardation physiopathology, Guanylate Cyclase analysis, Male, Muscle, Smooth, Vascular drug effects, Muscle, Smooth, Vascular enzymology, Nitric Oxide physiology, Nitroprusside pharmacology, Organ Size drug effects, Placenta blood supply, Placenta drug effects, Pregnancy, Prenatal Injuries physiopathology, Sheep, Sildenafil Citrate blood, Vasodilation drug effects, Fetal Growth Retardation chemically induced, Prenatal Injuries chemically induced, Sildenafil Citrate toxicity, Vasodilator Agents toxicity
- Abstract
Objective- The objective of this study was to investigate the effect of intravenous maternal sildenafil citrate (SC) administration on vascular function in growth-restricted fetal sheep. Approach and Results- Fetal growth restriction (FGR) results in cardiovascular adaptations that redistribute cardiac output to optimize suboptimal intrauterine conditions. These adaptations result in structural and functional cardiovascular changes, which may underlie postnatal neurological and cardiovascular sequelae. Evidence suggests SC, a potent vasodilator, may improve FGR. In contrast, recent clinical evidence suggests potential for adverse fetal consequence. Currently, there is limited data on SC effects in the developing fetus. We hypothesized that SC in utero would improve vascular development and function in an ovine model of FGR. Preterm lambs (0.6 gestation) underwent sterile surgery for single umbilical artery ligation or sham (control, appropriately grown) surgery to replicate FGR. Ewes received continuous intravenous SC (36 mg/24 h) or saline from surgery until 0.83 gestation. Fetuses were delivered and immediately euthanized for collection of femoral and middle cerebral artery vessels. Vessel function was assessed via in vitro wire myography. SC exacerbated growth restriction in growth-restricted fetuses and resulted in endothelial dysfunction in the cerebral and femoral vasculature, irrespective of growth status. Dysfunction in the cerebral circulation is endothelial, whereas smooth muscle in the periphery is the origin of the deficit. Conclusions- SC crosses the placenta and alters key fetal vascular development. Extensive studies are required to investigate the effects of SC on fetal development to address safety before additional use of SC as a treatment.
- Published
- 2019
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