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Placental transfer of the polybrominated diphenyl ethers BDE-47, BDE-99 and BDE-209 in a human placenta perfusion system: an experimental study.

Frederiksen M, Vorkamp K, Mathiesen L, Mose T, Knudsen LE - Environ Health (2010)

Bottom Line: PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour.Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue.Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Environment & Health, Institute of Public Health, University of Copenhagen, Oester Farimagsgade 5, DK-1014 Copenhagen K, Denmark.

ABSTRACT

Background: Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in consumer products. PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour. Thus, in utero exposure is of very high concern due to critical windows in fetal development.

Methods: A human ex vivo placenta perfusion system was used to study the kinetics and extent of the placental transfer of BDE-47, BDE-99 and BDE-209 during four-hour perfusions. The PBDEs were added to the maternal circulation and monitored in the maternal and fetal compartments. In addition, the perfused cotyledon, the surrounding placental tissue as well as pre-perfusion placental tissue and umbilical cord plasma were also analysed. The PBDE analysis included Soxhlet extraction, clean-up by adsorption chromatography and GC-MS analysis.

Results and discussion: Placental transfer of BDE-47 was faster and more extensive than for BDE-99. The fetal-maternal ratios (FM-ratio) after four hours of perfusion were 0.47 and 0.25 for BDE-47 and BDE-99, respectively, while the indicative permeability coefficient (IPC) measured after 60 minutes of perfusion was 0.26 h-1 and 0.10 h-1, respectively. The transport of BDE-209 seemed to be limited. These differences between the congeners may be related to the degree of bromination. Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue.

Conclusion: The transport of BDE-47 and BDE-99 indicates in utero exposure to these congeners. Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable. Our study demonstrates fetal exposure to PBDEs, which should be included in risk assessment of PBDE exposure of women of child-bearing age.

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Placenta perfusion of BDE-47 and BDE-99. Concentration (ng/ml) and standard deviation of four hour placenta perfusions of a) BDE-47 and b) BDE-99 after addition of 1 ng/mL of each congener to the maternal compartment at t = 0. (0-60 min: n = 5; 130-240 min: n = 4).
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Figure 1: Placenta perfusion of BDE-47 and BDE-99. Concentration (ng/ml) and standard deviation of four hour placenta perfusions of a) BDE-47 and b) BDE-99 after addition of 1 ng/mL of each congener to the maternal compartment at t = 0. (0-60 min: n = 5; 130-240 min: n = 4).

Mentions: In total, 89 samples of maternal and fetal perfusate, placental tissue and umbilical cord plasma from the five perfusions were analysed for PBDEs. The details of the five placenta perfusions are given in Table 1. The cotyledon of perfusion no. 3 was leaking towards the end of the perfusion, therefore only data from the first 60 min of this perfusion have been used. All experiments meet the success criteria on minimal leakage of fetal media (< 0.05 mL/min) and a fetal/maternal ratio (FM-ratio) for antipyrine transfer of at least 0.75 (Table 1). The oxygen transfer, glucose consumption and lactate production were monitored during the perfusion, and pH was kept in the physiological range (data not shown) [23]. It is realised that the final sampled volume of 42 ml removed from each reservoir may give a slightly different picture of transport when looking at exact values as in figures 1 and 2. As the exact same amount was removed from the fetal and maternal reservoir at the same time-points and the resulting concentration is unchanged by removal; the large sample-volume demanded by the analysis protocol for PBDE was allowed in these perfusions.


Placental transfer of the polybrominated diphenyl ethers BDE-47, BDE-99 and BDE-209 in a human placenta perfusion system: an experimental study.

Frederiksen M, Vorkamp K, Mathiesen L, Mose T, Knudsen LE - Environ Health (2010)

Placenta perfusion of BDE-47 and BDE-99. Concentration (ng/ml) and standard deviation of four hour placenta perfusions of a) BDE-47 and b) BDE-99 after addition of 1 ng/mL of each congener to the maternal compartment at t = 0. (0-60 min: n = 5; 130-240 min: n = 4).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2908602&req=5

Figure 1: Placenta perfusion of BDE-47 and BDE-99. Concentration (ng/ml) and standard deviation of four hour placenta perfusions of a) BDE-47 and b) BDE-99 after addition of 1 ng/mL of each congener to the maternal compartment at t = 0. (0-60 min: n = 5; 130-240 min: n = 4).
Mentions: In total, 89 samples of maternal and fetal perfusate, placental tissue and umbilical cord plasma from the five perfusions were analysed for PBDEs. The details of the five placenta perfusions are given in Table 1. The cotyledon of perfusion no. 3 was leaking towards the end of the perfusion, therefore only data from the first 60 min of this perfusion have been used. All experiments meet the success criteria on minimal leakage of fetal media (< 0.05 mL/min) and a fetal/maternal ratio (FM-ratio) for antipyrine transfer of at least 0.75 (Table 1). The oxygen transfer, glucose consumption and lactate production were monitored during the perfusion, and pH was kept in the physiological range (data not shown) [23]. It is realised that the final sampled volume of 42 ml removed from each reservoir may give a slightly different picture of transport when looking at exact values as in figures 1 and 2. As the exact same amount was removed from the fetal and maternal reservoir at the same time-points and the resulting concentration is unchanged by removal; the large sample-volume demanded by the analysis protocol for PBDE was allowed in these perfusions.

Bottom Line: PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour.Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue.Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Environment & Health, Institute of Public Health, University of Copenhagen, Oester Farimagsgade 5, DK-1014 Copenhagen K, Denmark.

ABSTRACT

Background: Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in consumer products. PBDEs may affect thyroid hormone homeostasis, which can result in irreversible damage of cognitive performance, motor skills and altered behaviour. Thus, in utero exposure is of very high concern due to critical windows in fetal development.

Methods: A human ex vivo placenta perfusion system was used to study the kinetics and extent of the placental transfer of BDE-47, BDE-99 and BDE-209 during four-hour perfusions. The PBDEs were added to the maternal circulation and monitored in the maternal and fetal compartments. In addition, the perfused cotyledon, the surrounding placental tissue as well as pre-perfusion placental tissue and umbilical cord plasma were also analysed. The PBDE analysis included Soxhlet extraction, clean-up by adsorption chromatography and GC-MS analysis.

Results and discussion: Placental transfer of BDE-47 was faster and more extensive than for BDE-99. The fetal-maternal ratios (FM-ratio) after four hours of perfusion were 0.47 and 0.25 for BDE-47 and BDE-99, respectively, while the indicative permeability coefficient (IPC) measured after 60 minutes of perfusion was 0.26 h-1 and 0.10 h-1, respectively. The transport of BDE-209 seemed to be limited. These differences between the congeners may be related to the degree of bromination. Significant accumulation was observed for all congeners in the perfused cotyledon as well as in the surrounding placental tissue.

Conclusion: The transport of BDE-47 and BDE-99 indicates in utero exposure to these congeners. Although the transport of BDE-209 was limited, however, possible metabolic debromination may lead to products which are both more toxic and transportable. Our study demonstrates fetal exposure to PBDEs, which should be included in risk assessment of PBDE exposure of women of child-bearing age.

Show MeSH
Related in: MedlinePlus