Placenta-targeted treatment with nMitoQ prevents an endothelin receptor-A pathway cardiac phenotype observed in adult male offspring exposed to hypoxia in utero.

Prenatal hypoxia is associated with enhanced susceptibility to cardiac ischemia-reperfusion (I/R) injury in adult offspring, however, the mechanisms remain to be fully investigated. Endothelin-1 (ET-1) is a vasoconstrictor that acts via endothelin A (ET _A ) and endothelin B (ET _B ) receptors and is essential in maintaining cardiovascular (CV) function. Prenatal hypoxia alters the ET-1 system in adult offspring possibly contributing to I/R susceptibility. We previously showed that ex vivo application of ET _A antagonist ABT-627 during I/R prevented the recovery of cardiac function in prenatal hypoxia-exposed males but not in normoxic males nor normoxic or prenatal hypoxia-exposed females. In this follow-up study, we examined whether placenta-targeted treatment with a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ) during hypoxic pregnancies could alleviate this hypoxic phenotype observed in adult male offspring. We used a rat model of prenatal hypoxia where pregnant Sprague-Dawley rats were exposed to hypoxia (11% O ₂ ) from gestational days ( GD ) 15-21 after injection with 100 μL saline or nMitoQ (125 μM) on GD15 . Male offspring were aged to 4 mo and ex vivo cardiac recovery from I/R was assessed. Offspring born from hypoxic pregnancies and treated with nMitoQ had increased cardiac recovery from I/R in the presence of ABT-627 compared with their untreated counterparts where ABT-627 prevented recovery. Cardiac ET _A levels were increased in males born from hypoxic pregnancies with nMitoQ treatment compared with saline controls (Western blotting). Our data indicate a profound impact of placenta-targeted treatment to prevent an ET _A receptor cardiac phenotype observed in adult male offspring exposed to hypoxia in utero. NEW & NOTEWORTHY In this follow-up study, we showed a complete lack of recovery from I/R injury after the application of an ET _A receptor antagonist (ABT-627) in adult male offspring exposed to hypoxia in utero while maternal treatment with nMitoQ during prenatal hypoxia exposure prevented this effect. Our data suggest that nMitoQ treatment during hypoxic pregnancies may prevent a hypoxic cardiac phenotype in adult male offspring.