Markers of Physical Integrity and Metabolic Viability of the Perfused Human Placental Lobule

Abstract

1. Peripheral lobules of term placentae obtained from healthy females at Caesarian section were perfused using separate maternal and fetal circulations for 6 h periods under either oxygenated or anoxic conditions. 2. Markers of physical integrity during setting-up and initial perfusion were establishment of dual perfusion within 25 min of placental delivery, pressure in the fetal capillary network less than 40 mmHg, leakage of perfusate from fetal to maternal compartments less than or equal to 2 ml/h, and overlap of maternal with fetal perfusion as indicated visually by appropriate blanching and verified by a fetal artery to vein oxygen gradient of greater than or equal to 90 mmHg. 3. Post-perfusion markers of metabolic viability were most reliably indicated by glucose consumption (oxygenated 7.8 +/- 1.5, anoxic 17.7 +/- 1.2 mmol/kg per h), lactate production (oxygenated 8.5 +/- 1.4, anoxic 33.9 +/- 2.5 mmol/kg per h) and human placental lactogen production (oxygenated 41.2 +/- 9.8, anoxic 12.2 +/- 3.4 mg/kg per h).

Human Placental Glucuronidation and Transport of 3′azido-3′-Deoxythymidine and Uridine Diphosphate Glucuronic Acid

“…Although the ␤-hCG production we observed was within one standard deviation of that reported for viable, oxygenated perfusion (Cannell et al, 1988), the standard deviations in previously published data were much larger than our figures. This is consistent with the findings of Boal et al (1997), who demonstrated that with 4 h of perfusion, AZT caused a significant reduction of ␤-hCG secretion compared with nonexposed placentas.…”

“…Biochemical and biophysical parameters of the perfusions presented in Table 1 are, in general, consistent with published values (Illsley et al, 1984;Cannell et al, 1988). Although the ␤-hCG production we observed was within one standard deviation of that reported for viable, oxygenated perfusion (Cannell et al, 1988), the standard deviations in previously published data were much larger than our figures.…”

“…Biochemical validation assays were performed by the Diagnostic Specimen Laboratory and National Testing Centre at Greenlane Hospital, Auckland, New Zealand. Viability was assessed according to the criteria described by Cannell et al (1988), such that establishment of both maternal and fetal circuits occurred within 30 min of delivery, pressure in the fetal circuit was Յ40 mm Hg, leakage of perfusate from fetal to maternal circuit was Ͻ2 ml/h, and tissue was blanched as perfusion proceeded. AZT transfer and metabolism was assessed in five placentas with samples (300 -400 l) collected from the maternal artery, maternal vein, fetal artery, and fetal vein at 0, 5, 10, 20, and 30 min and then at 1, 1.5, 2, 2.5, 3, 3.5, and 4 h, snap-frozen in liquid nitrogen, and stored at Ϫ80°C until analysis.…”

“…For transfer in the opposite direction, the inverse equation was used, where maternal arterial and venous concentration and flow rate were divided by the fetal concentration (Cannell et al, 1988). This equation is appropriate for compounds that reach equilibrium in the perfusion model.…”

“…Peripheral lobules from term placentas (n ϭ 5) were perfused using separate, recirculating maternal and fetal circuits. The procedure was based on the method of Cannell et al (1988) with some modifications. Briefly, a suitable artery/vein pair was selected, cannulated, and excised.…”