Diffusion characteristics of placental preparations affect the digoxin passage across the isolated placental lobule.
Our aim was to evaluate the isolated placental lobule to study maternofetal transplacental digoxin transfer and accumulation in placental tissue in vitro. Digoxin passage across the isolated lobule of 10 human placentas was calculated from repeated fetal and maternal perfusate samples, and placental tissue digoxin concentrations were measured at the end of the experiments. To determine the degree of overlap of the fetal and the maternal circulation, the antipyrine clearance was used. Digoxin disappearance from the maternal circuit was not significantly affected by the degree of overlap. In contrast, the increase of digoxin in the fetal compartment was significantly higher in "well-perfused" placentas (antipyrine clearance > 1.60 ml/min; n = 5) than in "malperfused" placentas (antipyrine clearance < 1.50 ml/min; n = 5) (end-feto to initial maternal digoxin ratio 0.44 +/- 0.08 vs. 0.30 +/- 0.08; p < 0.05), whilst the accumulation in placental tissue was higher in the latter group (0.45 +/- 0.07 vs. 0.62 +/- 0.10 ng/mg protein; p < 0.05). We conclude that the isolated placental lobule is suitable to quantify transplacental digoxin transfer in vitro, but the diffusion characteristics of each preparation have to be considered.
Schmolling
J
J
Department of Obstetrics and Gynecology, University of Bonn, Germany.
Jung
S
S
Reinsberg
J
J
Schlebusch
H
H
D000889:Anti-Arrhythmia Agents / Q000378:metabolism*; D000983:Antipyrine / Q000378:metabolism; D004058:Diffusion; D004077:Digoxin / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008431:Maternal-Fetal Exchange; D010477:Perfusion; D010920:Placenta / Q000098:blood supply / Q000378:metabolism*; D011247:Pregnancy
D000889:Anti-Arrhythmia Agents; D004077:Digoxin; D000983:Antipyrine