Ex ‐ Vivo MRI of the Normal Human Placenta: Structural–Functional Interplay and the Association With Birth Weight

Fifty normal human placentae from various gestations were analyzed for total DNA, RNA, and protein content. The data indicate that, although weight, RNA, and protein continue to increase linearly until term, the rate of increase in DNA rapidly declines when the placenta reaches about 300 gm or the fetus 2,300 gm. When these data are interpreted in terms of number and size of cells they suggest that cell division stops in human placenta about 1 month prior to term. The latter portion of placental growth is by enlargement of already existing cells. These data establish normal values for human placenta from 26 through 42 weeks and provide a base line to compare placentae of abnormal pregnancies.

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Human placental vitamin B6 (pyridoxal) transport: normal characteristics and effects of ethanol

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1992.262.6.r966 ◽

1992 ◽

Vol 262 (6) ◽

pp. R966-R974 ◽

Cited By ~ 4

Author(s):

S. Schenker ◽

R. F. Johnson ◽

J. D. Mahuren ◽

G. I. Henderson ◽

S. P. Coburn

Keyword(s):

Human Placenta ◽

Binding Sites ◽

Vitamin B6 ◽

Passive Transport ◽

Short Term ◽

Placental Transport ◽

Normal Human ◽

Important Form ◽

Composite Data ◽

In Pregnancy

The aims of this study were to define normal human placental transport of pyridoxal, an important form of vitamin B6 in pregnancy, and to determine the effect of short-term alcohol on this process. Our studies used the isolated single cotyledon from the term placenta. Pyridoxal crossed the human placenta readily in both directions, but the transfer was a little less than half that of antipyrine and was significantly greater in the direction of the fetus. Pyridoxine appeared to have a similar clearance from the maternal compartment as pyridoxal, but transport of intact pyridoxal 5'-phosphate was much smaller. There was no saturable transfer of pyridoxal, and it was not transferred from the maternal to fetal compartments against a concentration gradient. Placental concentration of pyridoxal exceeded both maternal and fetal perfusate pyridoxal concentrations, but this concentration was equal for both perfusion directions. These composite data are most suggestive of passive transport of pyridoxal across the placenta, binding of the vitamin in the placenta as an explanation for its concentration there, and greater phosphorylation of pyridoxal in the placenta when the compound is transferred in the fetal direction, possibly displacing pyridoxal from its binding sites and permitting its greater release into the fetal compartment. Alcohol, 400-250 mg/dl over 2.5 h, inhibited the transport of pyridoxal from the maternal to fetal compartments by approximately 42% (P = 0.03) and resulted in a lower transfer of pyridoxal 5'-phosphate into the fetal perfusate (P = 0.02).

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Plasma proteins facilitates placental transfer of polystyrene particles

Journal of Nanobiotechnology ◽

10.1186/s12951-020-00676-5 ◽

2020 ◽

Vol 18 (1) ◽

Cited By ~ 1

Author(s):

Michael M. Gruber ◽

Birgit Hirschmugl ◽

Natascha Berger ◽

Magdalena Holter ◽

Snježana Radulović ◽

...

Keyword(s):

Human Plasma ◽

Human Placenta ◽

Plasma Proteins ◽

Placental Transfer ◽

Ex Vivo ◽

Biological Fluids ◽

Protein Corona ◽

Human Albumin ◽

Placental Perfusion ◽

The Impact

Abstract Background Nanoparticles, which are exposed to biological fluids are rapidly interacting with proteins and other biomolecules forming a corona. In addition to dimension, charge and material the distinct protein corona influences the interplay of nanoparticles with tissue barriers. In this study we were focused on the impact of in situ formed human plasma protein corona on the transfer of 80 nm polystyrene nanoparticles (PS-particles) across the human placenta. To study materno-to fetal PS transfer we used the human ex vivo placental perfusion approach, which represents an intact and physiological tissue barrier. To analyze the protein corona of PS particles we performed shotgun proteomics of isolated nanoparticles before and after tissue exposure. Results Human plasma incubated with PS-particles of 80 nm and subsequent formed protein corona enhanced the transfer across the human placenta compared to PS-corona formed by bovine serum albumin and dextran which served as a control. Quantitative and qualitative changes of plasma proteins determined the changes in PS transfer across the barrier. Based on the analysis of the PS-proteome two candidate proteins, namely human albumin and immunoglobulin G were tested if these proteins may account for the enhanced PS-transfer across the placenta. Interestingly, the protein corona formed by human albumin significantly induced the transfer of PS-particles across the tissue compared to the formed IgG-corona. Conclusion In total we demonstrate the PS corona dynamically and significantly evolves upon crossing the human placenta. Thus, the initial composition of PS particles in the maternal circulation is not predictive for their transfer characteristics and performance once beyond the barrier of the placenta. The precise mechanism of these effects remains to be elucidated but highlights the importance of using well designed biological models when testing nanoparticles for biomedical applications.

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