Hypertensive disorder in pregnancy is a major cause of maternal and perinatal mortality worldwide. Women who have had preeclampsia are at three to four times higher risk in later life of developing high blood pressure and heart disease. Soluble Flt-1 (sFlt-1) is elevated in preeclampsia and may remain high postpartum in women with a history of preeclampsia. Heme oxygenase-1 (Hmox1/HO-1) exerts protective effects against oxidative stimuli and is compromised in the placenta of pregnant women with preeclampsia. We hypothesized that sFlt-1 inhibits cardiac mitochondrial activity in HO-1 deficient mice. HO-1 haplo-insufficient mice (Hmox1+/-) were injected with adenovirus encoding sFlt-1 (Ad-sFlt-1) or control virus (Ad-CMV). Subsequently, they were treated daily with either placebo or MZe786 for six days, when the heart tissue was harvested to assess cardiac mitochondrial activity. Here, we show that the loss of HO-1 disturbed cardiac mitochondrial respiration and reduced mitochondrial biogenesis. The overexpression of sFlt-1 resulted in the inhibition of the cardiac mitochondrial activity in Hmox1+/- mice. The present study demonstrates that the hydrogen sulfide (H2S) releasing molecule, MZe786, rescues mitochondrial activity by stimulating cardiac mitochondrial biogenesis and antioxidant defense in Hmox1-/- mice and in Hmox1+/- mice exposed to a high sFlt-1 environment.

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