Placental metabolite profiles in late gestation for healthy mice

Differential impact of perfluorooctanoic acid and fluorotelomer ethoxylates on placental metabolism in mice

Poly- and perfluoroalkyl substances (PFAS) are a group of compounds with uses in industry and many consumer products. Concerns about the potential health effects of these compounds resulted in regulation by the Stockholm Convention on the use of three of the most common PFAS, including perfluorooctanoic acid (PFOA). Thousands of PFAS remain in production that are unregulated and for which their toxicity is unknown. Our group recently identified a new class of PFAS, fluorotelomer ethoxylates (FTEOs), in indoor dust and industrial wastewater. In this study, we investigated the effect of PFAS on placental metabolism by exposing healthy, pregnant CD-1 mice to PFOA or FTEOs at one of three concentrations (0 ng/L (controls), 5 ng/L, 100 ng/L) (n = 7-8/group). While PFOA is banned and PFOA concentrations in human blood are decreasing, we hypothesize that FTEOs will cause adverse pregnancy outcomes similar to PFOA, the compounds they were meant to replace. Placental tissue samples were collected at embryonic day 17.5 and 1H solid-state magic angle spinning nuclear magnetic resonance spectroscopy was used to determine the relative concentration of placental metabolites (n = 18-20/group). At the highest concentration, the relative concentrations of glucose and threonine were increased and the relative concentration of creatine was decreased in the PFOA-exposed placentas compared to controls (p < 0.05). In contrast, the relative concentrations of asparagine and lysine were decreased and the relative concentration of creatine was increased in the FTEOs-exposed placentas compared to controls (p < 0.05). Partial least squares - discriminant analysis showed the FTEOs-exposed and control groups were significantly separated (p < 0.005) and pathway analysis found four biochemical pathways were perturbed following PFOA exposure, while one pathway was altered following FTEOs exposure. Maternal exposure to PFOA and FTEOs had a significant impact on the placental metabolome, with the effect depending on the pollutant. This work motivates further studies to determine exposure levels and evaluate associations with adverse outcomes in human pregnancies.

Maternal exposure to polystyrene nanoplastics alters fetal brain metabolism in mice

INTRODUCTION

Plastics used in everyday materials accumulate as waste in the environment and degrade over time. The impacts of the resulting particulate micro- and nanoplastics on human health remain largely unknown. In pregnant mice, we recently demonstrated that exposure to nanoplastics throughout gestation and during lactation resulted in changes in brain structure detected on MRI. One possible explanation for this abnormal postnatal brain development is altered fetal brain metabolism.

OBJECTIVES

To determine the effect of maternal exposure to nanoplastics on fetal brain metabolism.

METHODS

Healthy pregnant CD-1 mice were exposed to 50 nm polystyrene nanoplastics at a concentration of 106 ng/L through drinking water during gestation. Fetal brain samples were collected at embryonic day 17.5 (n = 18-21 per group per sex) and snap-frozen in liquid nitrogen. Magic angle spinning nuclear magnetic resonance was used to determine metabolite profiles and their relative concentrations in the fetal brain.

RESULTS

The relative concentrations of gamma-aminobutyric acid (GABA), creatine and glucose were found to decrease by 40%, 21% and 30% respectively following maternal nanoplastic exposure when compared to the controls (p < 0.05). The change in relative concentration of asparagine with nanoplastic exposure was dependent on fetal sex (p < 0.005).

CONCLUSION

Maternal exposure to polystyrene nanoplastics caused abnormal fetal brain metabolism in mice. The present study demonstrates the potential impacts of nanoplastic exposure during fetal development and motivates further studies to evaluate the risk to human pregnancies.

Identifying placental metabolic biomarkers of preterm birth using nuclear magnetic resonance of intact tissue samples

INTRODUCTION

Our understanding of the etiology of preterm birth (PTB) is incomplete; however, recent evidence has found a strong association between placental dysfunction and PTB. Altered placental metabolism may precede placental dysfunction and therefore the study of placental metabolic profiles could identify early biomarkers of PTB. In this study, we evaluated the placental metabolome in PTB in intact tissue samples using nuclear magnetic resonance (NMR) and spectral editing.

METHODS

Placental tissue samples were collected from nine term pregnancies and nine preterm pregnancies (<37 weeks' gestation). 1H NMR experiments on unprocessed tissue samples were performed using a high field magnet (500 MHz spectrometer) and a comprehensive multiphase NMR probe. The relative concentrations of 23 metabolites were corrected for gestational age and compared between groups.

RESULTS

The relative concentration of valine, glutamate and creatine were significantly decreased while alanine, choline and glucose were elevated in placentas from PTB pregnancies compared to controls (p < 0.05). Multivariate analysis using principal component analysis showed the PTB and control groups were significantly separated (p < 0.0001) and pathway analysis identified perturbations in the glycine, serine and threonine metabolism, aminoacyl-tRNA biosynthesis and valine, leucine and isoleucine biosynthesis pathways.

CONCLUSION

PTB is associated with significant alterations in placental metabolism. This study helps improve our understanding of the etiology of PTB. It also highlights the potential for small molecule metabolites to serve as placental metabolic biomarkers to aid in the prediction and diagnosis of PTB. The results can be translated to clinical use via in utero magnetic resonance spectroscopy.

Maternal exposure to polystyrene microplastics alters placental metabolism in mice

INTRODUCTION

The rapid growth in the worldwide use of plastics has resulted in a vast accumulation of microplastics in the air, soil and water. The impact of these microplastics on pregnancy and fetal development remains largely unknown. In pregnant mice, we recently demonstrated that exposure to micro- and nanoplastics throughout gestation resulted in significant fetal growth restriction. One possible explanation for reduced fetal growth is abnormal placental metabolism.

OBJECTIVES

To evaluate the effect of maternal exposure to microplastics on placental metabolism.

METHODS

In the present study, CD-1 pregnant mice were exposed to 5 μm polystyrene microplastics in filtered drinking water at one of four concentrations (0 ng/L (controls), 10² ng/L, 10⁴ ng/L, 10⁶ ng/L) throughout gestation (n = 7-11/group). At embryonic day 17.5, placental tissue samples were collected (n = 28-44/group). Metabolite profiles were determined using ¹ H high-resolution magic angle spinning magnetic resonance spectroscopy.

RESULTS

The relative concentration of lysine (p = 0.003) and glucose (p < 0.0001) in the placenta were found to decrease with increasing microplastic concentrations, with a significant reduction at the highest exposure concentration. Multivariate analysis identified shifts in the metabolic profile with MP exposure and pathway analysis identified perturbations in the biotin metabolism, lysine degradation, and glycolysis/gluconeogenesis pathways.

CONCLUSION

Maternal exposure to microplastics resulted in significant alterations in placental metabolism. This study highlights the potential impact of microplastic exposure on pregnancy outcomes and that efforts should be made to minimize exposure to plastics, particularly during pregnancy.