The differential regulation of placenta trophoblast bisphosphoglycerate mutase in fetal growth restriction: preclinical study in mice and observational histological study of human placenta
- Immunology and Regenerative Biology, Weizmann Institute of Science, Israel
- Chemical Research Support Weizmann Institute of Science, Israel
- Veterinary Resources, Weizmann Institute of Science, Israel
- Life Science Core Facilities, Weizmann Institute of Science, Israel
- OBGYN, Meir Medical Center, Israel
- Tel Aviv University, School of Medicine, Israel
Figures
Figure 1
Gestational hypoxia elevates maternal hemoglobin, hematocrit and blood acidity, and recapitulates FGR phenotype in mice.
(A–B) Graphs showing hematocrit and hemoglobin levels in maternal venous blood. (C) Graph shows pH levels in maternal venous blood. (D–F) Graphs showing litter size, fetal weight and placental weight. (G) Representative picture of fetuses and placentae (E16.5) from control and gestational hypoxia groups. (H–I) Analysis of the percentage of small for gestational age (SGA, weight less than the 10th percentile) fetuses and placentae, large for gestational age (LGA, weight greater than the 90th percentile) fetuses and placentae, and appropriate for gestational age (AGA, weight between the 10th and 90th percentiles) fetuses and placentae at E16.5. Scale bars: 1 cm. Data displayed as mean ± SD and are from 49 to 62 fetuses and placentae from 6 to 7 dams per group (8–9 conceptuses per litter used). Ordinary one-way ANOVA test was used for statistical analysis.
Figure 2
Maternal hypoxia during gestation results in enlarged spiral arteries, increased RBC levels and decreased placental labyrinth area.
(A, B) Placentae of hypoxic chamber groups have significantly smaller labyrinth area in comparison to the control group. (C, D), (E, F) Placentae of hypoxic chamber groups display enlarged spiral arteries and increased RBC levels in the labyrinth. Scale bars: 40 μm. Data are from 3 control, 4 chronic hypoxia and 4 acute hypoxia dams, 5–7 placentae per dam and presented as mean ± SD values. Ordinary one-way ANOVA test was used for statistical analysis.
Figure 3 with 4 supplements
Effects of maternal hypoxia during gestation on R2* values following hyperoxia-hypoxia challenge.
(A–H) Graphs show that hypoxic challenge results in elevation in R2* values in maternal aortas of chronic hypoxia chamber group, while no differences are observed in the respective placentae and fetuses. (I) Representative R2* images of control and hypoxic chamber group show several fetuses and their placenta (P), heart (H) and liver (L). Scale bars: 0.5 cm. (J) Representative R2* maps inside the placenta of control, acute hypoxia (AH) and chronic hypoxia (CH) chamber groups at E16.5 show distribution of R2* values following hyperoxia-hypoxia challenge. Data are from 8 control, 6 acute hypoxia and 7 chronic hypoxia per dams presented as mean ± SD values. R2* values of embryonic tissues and placentae are calculated as the median per mother, 5–8 embryos per each mother. Ordinary one-way ANOVA test was used for statistical analysis.
Figure 3—figure supplement 1
Effects of maternal hypoxia during gestation on R2* values following hyperoxia-hypoxia challenge.
(A) Representative R2* images of control and hypoxic chamber group show several dams and their liver (L), aorta (A) and vena cava (V). Scale bars: 0.5 cm.
Figure 3—video 1
MR imaging of mother, embryos, and placentae: Representative MRI scan videos of control dams.
Figure 3—video 2
MR imaging of mother, embryos, and placentae: Representative MRI scan videos of acute hypoxia dams.
Figure 3—video 3
MR imaging of mother, embryos, and placentae: Representative MRI scan videos of chronic hypoxia dams.
Figure 4 with 2 supplements
Maternal hypoxia during gestation results in elevated placental BPGM expression levels.
(A) Representative images of BPGM, SynI, and SynII expression and co-localization (arrows) in the placental labyrinth at E16.5. Scale bars: 5 μm. (B,E) Representative images and quantification of BPGM expression in the placental labyrinth at E16.5 of control and hypoxic chamber groups. Scale bars: 30 μm. (C,D,F) Trophoblast cells lining the arteries show an increase of BPGM expression in chronic hypoxia group. The expression of BPGM is restricted to the apical trophoblast cell side facing the arterial lumen. Scale bars: 30 μm. (C), 10 μm (D). Data are from 3 control, 4 chronic hypoxia and 4 acute hypoxia dams, 2–3 placentae per group and presented as mean ± SD values. Ordinary one-way ANOVA test was used for statistical analysis.
Figure 4—figure supplement 1
BPGM expression in a control murine placenta.
BPGM expression is restricted to the labyrinth area.
Figure 4—figure supplement 2
Negative controls for the BPGM IHC.
The positive signal comes from the RBC auto fluorescence.
Figure 5 with 1 supplement
Hif1a is upregulated in acute hypoxic placentae.
(A,D) Representative images and quantification of Hif1a and Hif2a expression in the placental labyrinth at E16.5 of control and hypoxic chamber groups. Scale bars: 10 μm (A,C). Data are from two to three placentae per group, each from different litter and presented as mean + SD values. Ordinary one-way ANOVA test was used for statistical analysis.
Figure 5—figure supplement 1
Murine BPGM promoter analysis, showing potential Hif1a binding sites.
Figure 6
Patient selection flow chart.
16 Pregnant women were recruited from the Meir and Wolfson Medical Centers.
Figure 7
Human FGR placentae exhibit lower BPGM and 2,3 BPG levels.
(A, B) Representative images of BPGM expression in control and FGR placentae. Scale bars: 30 μm. (C) Graph representing intensity of BPGM expression in control and FGR placentae. (D–F) Levels of 2,3 BPG in maternal and cord serum of control and FGR placentae. Data are from 9 control and 7 FGR women and presented as mean ± SD values. Unpaired t test was used for statistical analysis.
Figure 8
Proposed model of placental adaptation to oxygen transfer during the course of gestation.
Expression of BPGM, a key enzyme affecting the release of oxygen from hemoglobin, is augmented in the murine placenta challenged by gestational hypoxia in mice, while its expression is attenuated in placenta of human FGR. The placental upregulation of BPGM might be mediated via Hif1a.
Author response image 1
Author response image 2
Maternal visceral adipose tissue levels.
(A-C) Representative images of the maternal VAT (arrows), atE16.5 of control and hypoxic chamber groups. (D) VAT width in control and hypoxia groups, Ordinary one-way ANOVA test was used for statistical analysis.
Tables
Table 1
Clinical parameters of women included in the study.
Clinical parameters did not differ among the groups, except for birthweight, which was significantly lower in the FGR group (Unpaired t-test, p=0.0004).
| Parameter | Controln=9 | FGRn=7 | p value |
|---|---|---|---|
| Maternal age, mean ±SD, years | 30.2±5.6 | 29.14±5.6 | 0.7291 |
| Gestational age, mean ±SD, weeks | 38.2±1 | 37.5±0.6 | 0.1644 |
| Preterm delivery (<37), n (%) | 0 | 0 | |
| Pregravid BMI (kg/m2), mean ±SD | 22.8±4.5 | 27.1±3.6 | 0.2598 |
| Gravidity, median (IQR) | 2.3 (1.5) | (2) | |
| Parity, median (IQR) | 1.2 (1.5) | 1 (2) | |
| Maternal comorbidities, n (%) | |||
| Hypertensive disorders | 0 | 0 | |
| Diabetes or gestational diabetes | 1 (11) | 1 (14) | |
| Asthma | 0 | 0 | |
| Thyroid disease | 0 | 0 | |
| Smoker | 5 | 3 | |
| Infant sex, n (%) | |||
| Male | 7 (77) | 4 (57) | |
| Female | 2 (23) | 3 (43) | |
| Birthweight, mean ±SD, grams | 3167±494 | 2189.4±189 | ***0.0004 |
| NICU, n (%) | 0 | 1 (14) |
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The differential regulation of placenta trophoblast bisphosphoglycerate mutase in fetal growth restriction: preclinical study in mice and observational histological study of human placenta
eLife 13:e82631.
https://doi.org/10.7554/eLife.82631
