Fibrin-Type Fibrinoid in Human Placenta: A Stereological Analysis of Its Association With Intervillous Volume and Villous Surface Area

Abstract

Stereological methods were used to examine fibrin-type fibrinoid deposition in the intervillous spaces of human placentas collected during gestation (12-41 weeks) and from term pregnancies at low (400 m) and high (3.6 km) altitude. The main aim was to test predictions about the relationships between fibrinoid deposits and either the volume of intervillous space or the surface area of (intermediate + terminal) villi. Fields of view on Masson trichrome-stained paraffin sections were selected as part of a systematic sampling design which randomised section location and orientation. Relative and absolute volumes were estimated by test point counting and surfaces by intersection counting. Apparent differences were tested by analyses of variance and relationships by correlation and regression analysis. Fibrinoid volume increased during gestation and correlated positively with intervillous volume and villous surface area. However, relative to intervillous volume, the main increase in fibrinoid occurred towards term (36-41 weeks). At high altitude, placentas contained more intervillous space but less fibrinoid. At both altitudes, there were significant correlations between fibrinoid volume and villous surface area. In all cases, changes in fibrinoid volume were commensurate with changes in villous surface area. Whilst findings lend support to the notion that fibrinoid deposition during normal gestation is influenced by the quality of vascular perfusion, they also emphasise that the extent of the villous surface is a more generally important factor. The villous surface may influence the steady state between coagulation and fibrinolysis since some pro-coagulatory events operate at the trophoblastic epithelium. They occur notably at sites of trophoblast de-epithelialisation and these arise following trauma or during the extrusion phase of normal epithelial turnover.

Histomorphometric parameters of normal full term placenta of Sudanese women

“…Furthermore, values of 13 M 2 and 11 M 2 were reported for two Brazilian ethnic groups [24] . Similar values were found in the normal placenta of Bolivian and Bosnian women [ 31 , 32 ]. The increase in the surface density of the villi in the human placenta indicates morphologically a more profuse branching of the villi [8] .…”

Prediction of Maternal and Fetoplacental Concentrations of Cefazolin, Cefuroxime, and Amoxicillin during Pregnancy Using Bottom-Up Physiologically Based Pharmacokinetic Models

“…Where PSA is polar surface area and HBD is the Hydrogen bond donor of the compound, while PVSA is the placenta villus surface area at term (PVSA =11 m 2 (Boyd, 1984;Teasdale and Jean-Jacques, 1985;Mayhew, 2001)), Vol.Placenta is the placenta volume at term in mL (665 mL) and 3.6 is a unit conversion scalar. The placental permeability clearance input in the model is in mL/min/mL of placental volume unit.…”

Mechanistic Framework to Predict Maternal‐Placental‐Fetal Pharmacokinetics of Nifedipine Employing Physiologically Based Pharmacokinetic Modeling Approach

“…The nifedipine apparent permeability across Caco‐2 cells (52.3 × 10 −6 cm/s) 28 was used to estimate the effective permeability (5.39 × 10 −4 cm/s). This value was further adjusted by the placental villi surface area 29 of 11.8 m 2 and then divided by the placental volume of 670 mL at term, 30 resulting in CL PD of 0.33848 L/h/mL placenta. This CL PD was used as a model input parameter for determining passive diffusion clearances on both sides of the placenta, under the assumption of a placental density of 1 g/mL.…”