Background

In humans, maternal obesity has been linked to greater placental mitochondrial content and lipotoxicity which may contribute to altered offspring outcomes. Thus, interventions to improve maternal health during pregnancy are needed. In a RCT, we compared placental mitochondrial respiration of obese women who consumed probiotics (PR, B. Lactis bb 12® and L. rhamnosus GG, n=12) vs. placebo (PL, n=7) from gestation week 12 until delivery.

Methods

Mitochondrial respiration was measured using high resolution respirometry (HRR). A protocol that provides information on the fatty oxidation pathway (FAO) was applied: 1) Octanoylcarnitine + Malate (OctM). 2) Complex (C) I-linked substrates (pyruvate and glutamate, FAO&CI). 3) CII-linked substrate (Succinate, FAO&CI&CII). 4) Glycerophosphate (Gp, FAO&CI&CII&Gp): 5) FCCP obtained electron transport capacity (ET, uncoupled ET state). 6) Rotenone and antimycin-A measured residual oxygen consumption (ROX). Data were normalized per mg of tissue, and with flux control ratios (FCR) to account for potential differences in mitochondrial content. Data presented as mean±SEM. HRR data presented in pmol O2•s-1•mg-1.

Results

BMI (PR=36±1 vs. PL=36±2 kg/m2) at enrollment, and gestational age at delivery (PR=39± 0.4 vs. PL=39± 0.3 wk) were comparable between groups. FAO (PR=3.4±0.6 vs. PL=5.3±0.6, p=0.062); FAO&CI (PR=5.0±0.4 vs. PL=8.0±0.9, p=0.009); FAO&CI&CII (PR=11.9±1.1 vs. PL=17.5±1.4, p=0.009); FAO&CI&CII&Gp (PR=13.9±1.3 vs. PL=19.5±1.7, p=0.025); ET (PR=22.8±2.1 vs. PL=29.7±2.2, p=0.043); ROX (PR=1.8±0.8 vs. PL=6.4±5.7, p=0.023) decreased with PR supplementation. When FCR were created no differences were seen between groups suggesting a mediation via altered mitochondrial content.

Conclusions

Placental mitochondrial respiration of obese women decreases with probiotic supplementation during pregnancy potentially through a decrease in placenta mitochondrial content. The mechanisms involved will be further investigated. NIH-P20GM109096, USDA-ARS 6026-51000-010-05S