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Sildenafil therapy for fetal cardiovascular dysfunction during hypoxic development: studies in the chick embryo.

Accepted version
Peer-reviewed

Type

Article

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Authors

Itani, Nozomi 
Skeffington, Katie L 
Beck, Christian 

Abstract

KEY POINTS: Common complications of pregnancy, such as chronic fetal hypoxia, trigger a fetal origin of cardiovascular dysfunction and programme cardiovascular disease in later life. Sildenafil treatment protects placental perfusion and fetal growth, but whether the effects of sildenafil transcend the placenta to affect the fetus is unknown. Using the chick embryo model, here we show that sildenafil treatment directly protects the fetal cardiovascular system in hypoxic development, and that the mechanisms of sildenafil protection include reduced oxidative stress and increased nitric oxide bioavailability; Sildenafil does not protect against fetal growth restriction in the chick embryo, supporting the idea that the protective effect of sildenafil on fetal growth reported in mammalian studies, including humans, is secondary to improved placental perfusion. Therefore, sildenafil may be a good candidate for human translational antioxidant therapy to protect the chronically hypoxic fetus in adverse pregnancy. ABSTRACT: There is a need for developing clinically translatable therapy for preventing fetal origins of cardiovascular disease in pregnancy complicated by chronic fetal hypoxia. Evidence shows that sildenafil protects placental perfusion and fetal growth. However, whether beneficial effects of sildenafil transcend onto the fetal heart and circulation in complicated development is unknown. We isolated the direct effects of sildenafil on the fetus using the chick embryo and hypothesised that sildenafil also protects fetal cardiovascular function in hypoxic development. Chick embryos (n = 11 per group) were incubated in normoxia or hypoxia (14% O2 ) from day 1 and treated with sildenafil (4 mg kg-1  day-1 ) from day 13 of the 21-day incubation. Hypoxic incubation increased oxidative stress (4-hydroxynonenal, 141.1 ± 17.6% of normoxic control), reduced superoxide dismutase (60.7 ± 6.3%), increased phosphodiesterase type 5 expression (167 ± 13.7%) and decreased nitric oxide bioavailability (54.7 ± 6.1%) in the fetal heart, and promoted peripheral endothelial dysfunction (70.9 ± 5.6% AUC of normoxic control; all P < 0.05). Sildenafil treatment after onset of chronic hypoxia prevented the increase in phosphodiesterase expression (72.5 ± 22.4%), protected against oxidative stress (94.7 ± 6.2%) and normalised nitric oxide bioavailability (115.6 ± 22.3%) in the fetal heart, and restored endothelial function in the peripheral circulation (89.8 ± 2.9%). Sildenafil protects the fetal heart and circulation directly in hypoxic development via mechanisms including decreased oxidative stress and enhanced nitric oxide bioavailability. Sildenafil may be a good translational candidate for human antioxidant therapy to prevent fetal origins of cardiovascular dysfunction in adverse pregnancy.

Description

Keywords

Antioxidant, endothelial function, fetus, sildenafil, Animals, Chick Embryo, Cyclic Nucleotide Phosphodiesterases, Type 5, Heart, Hematocrit, Hypoxia, Nitric Oxide, Oxidative Stress, Phosphodiesterase 5 Inhibitors, Sildenafil Citrate, Superoxide Dismutase

Journal Title

J Physiol

Conference Name

Journal ISSN

0022-3751
1469-7793

Volume Title

595

Publisher

Wiley
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/E002668/1)
British Heart Foundation (None)
British Heart Foundation (None)
British Heart Foundation (None)
British Heart Foundation (None)
British Heart Foundation (None)
British Heart Foundation.