The volume of villi with γ-sm-actin positive perivascular cells correlates with placental weight and thickness.

Introduction: The classification of histologically stained villous cross sections in villous types (terminal, intermediate and stem villi) by stromal peculiarities is known to be observer predicated. Therefore, quantitative histology of villous trees has not become a routine endpoint of studies on the role of the placenta in prenatal programming, as opposed to the gross placental parameters weight and thickness. The classification of villous cross sections in central (stem) and peripheral (terminal) parts based on the presence or absence, respectively, of immunohistochemical detection of myofibroblasts in perivascular position is less observer dependent.

Novel 3D microscopic analysis of human placental villous trees reveals unexpected significance of branching angles.

The villous trees of human placentas delineate the fetomaternal border and are complex three-dimensional (3D) structures. Thus far, they have primarily been analyzed as thin, two-dimensional (2D) histological sections. However, 2D sections cannot provide access to key aspects such as branching nodes and branch order.