(P04-016-24) Maternal Nitrate Supplementation As Adjuvant Therapy During a Hypertensive Pregnancy on Body Composition and Oxidative Stress

Objectives: Hypertension during pregnancy leads to excessive oxidative stress (OS), risk for fetal growth restriction, and altered body composition throughout life partially due to inadequate placental perfusion resulting from OS. Dietary nitrate is known to reduce blood pressure and OS in adults; however, little is known regarding its impact on expectant women and their offspring. This study assessed concomitant nitrate supplementation with an anti-hypertensive medication on spontaneously hypertensive rat (SHR) dams and their offspring on oxidative stress and body composition.

Methods: Twenty-week-old female SHR were randomized to control SHR (n=4), nitrate (N) (21 mg/day) (n=4), labetalol (L) (20 mg/kg/day) (n=4), or nitrate and labetalol (N+L) (n=4) for four weeks prior to mating and continued through weaning. OS was assessed as thiobarbituric acid reactive substances in SHR dams at necropsy (postnatal day 40 (P40)) and offspring at P40 and P60 in serum. Body weight (BW) was assessed along with body composition (% lean and fat mass) via bioimpedance spectroscopy for offspring at P25, P40, and P60.

Results: At P25, control pups had lower BW than N (p=0.026) and N+L pups (p=0.029). Control also had less lean mass than N (p=0.019) and L pups (p=0.020) but more lean mass than N+L pups (p=0.027). At P40, control pups had higher BW than L pups (p=0.045) while N pups had greater BW than L (p=0.048) and N+L pups (p=0.033). Additionally, control pups had less fat mass than N pups (p=0.023). Also at P40, control SHR dams had significantly greater OS than L (p=0.036) and N+L dams (p=0.039). At P40, control pups had greater OS than N, L, and N+L pups (p < 0.001). N also had greater OS than N+L (p=0.012) and L had greater OS than N+L pups (p=0.025). At P60, control pups had greater lean mass than N (p=0.001), L (p=0.039), and N+L (p=0.028) pups. At P60, control had greater OS than L (p=0.046) and N+L pups (p=0.024) with no other between group significance.

Conclusions: Maternal nitrate supplementation with labetalol imparts beneficial impacts on maternal and offspring OS. Further, nitrate supplementation had varying impact on offspring body composition across the lifespan. Additional research is warranted to evaluate the epigenetic mechanisms that underpin the maternal and offspring effects of nitrate during pregnancy.

Funding Sources: American Heart Association and Academy of Nutrition and Dietetics