High maternal BMI and low maternal blood BDNF may determine the limit of detection of amniotic fluid BDNF throughout gestation: Analysis of mother-fetus trios and literature review

Anne Flöck,Ramona Dolscheid-Pommerich,Brigitte Strizek,Alexandru Odainic,Marie Therese Puth,Waltraut Maria Merz,Susanne Schmidt,Anna Katharina Diedrich,Birgit Stoffel-Wagner,Ulrich Gembruch,Michael Robert Jaskolski,Pal Bela Szecsi

doi:10.1371/journal.pone.0265186

Abstract

ObjectiveAn increasing number of studies show the importance of brain-derived neurotrophic factor (BDNF) acting at the feto-placental interface, however, only a few studies describe BDNF levels in amniotic fluid (AF).MethodsIn this cross-sectional, prospective study, 109 maternal blood-amniotic fluid pairs (including 66 maternal blood-fetal-blood-amniotic fluid trios) were analyzed. BDNF concentrations were measured with a commercially available immunoassay.ResultsIn 71 AF from 109 samples, AF-BDNF concentrations were below the lowest limit of Quantitation (LLoQ) of 1.19 pg/ml (group A), leaving 38 samples with measurable BDNF concentrations (group B). Patients in group A showed significantly higher maternal BMI before pregnancy (mean±SD 26.3± 6.7 (kg/m2) vs. 23.8 ±4.5 (kg/m2) p = 0.04) and lower maternal blood BDNF concentrations than the other group (mean±SD 510.6 ± 554.7 pg/ml vs. mean±SD 910.1± 690.1 pg/ml; p<0.0001). Spearman correlation showed a negative correlation between maternal BMI before pregnancy and maternal BDNF concentrations (r = -0.25, p = 0.01).ConclusionOur study is the first to correlate AF-BDNF samples with the corresponding maternal and fetal blood-BDNF samples. The significant negative correlation between maternal BMI before pregnancy and maternal BDNF and AF-BDNF concentrations below the limit of detection has to be evaluated in further studies.

Highlights

Brain-derived neurotrophic factor (BDNF) is involved in energy metabolism [1,2] and various CNS functions [3,4]
In 71 Amniotic fluid (AF) from 109 samples, AF-brain-derived neurotrophic factor (BDNF) concentrations were below the lowest limit of Quantitation (LLoQ) of 1.19 pg/ml, leaving 38 samples with measurable BDNF concentrations
Spearman correlation showed a negative correlation between maternal BMI before pregnancy and maternal BDNF concentrations (r = -0.25, p = 0.01)

Summary

Introduction

Brain-derived neurotrophic factor (BDNF) is involved in energy metabolism [1,2] and various CNS functions [3,4]. Reduction in brain-derived neurotrophic factor (BDNF) expression in the brain as well as mutations in BDNF gene or its receptor are associated with obesity in human and animal models [5]. An increasing number of studies show the importance of BDNF acting at the feto-placental interface and a key role for BDNF in fetal growth and development is assumed [6–8]. BDNF promotes implantation and placental development [9]; levels rise with gestational age (GA) [10,11]. Investigations in mice and rats suggest that maternal BDNF reaches the fetal brain through the utero-placental barrier and may contribute to its development [12–14]. Amniotic fluid (AF) is a complex composition of fetal and maternal fluid and cellular components. BDNF in maternal serum predominantly reflects levels in platelets [20], but the source of AF-BDNF is unknown. BDNF has been found in urine of healthy individuals, but likewise its source has yet to be identified [21,22]

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Results

Conclusion