Does 2D-Histologic identification of villous types of human placentas at birth enable sensitive and reliable interpretation of 3D structure?
BACKGROUND
The villous tree of human placentas is a complex three-dimensional (3D) structure which enables fetomaternal exchange. Current concepts of microscopic analyses are based on the analysis of two-dimensional (2D) histologic sections. For this approach, the assessment of the stromal core of sectioned villi is of key importance. The classification of stromal properties of sectioned villi allows allocation of villous sections to villous types which are named by their expected position in villous trees (terminal, intermediate, and stem villi).


METHODS
The present study takes these current concepts of placental histology as hypothesis and validates them against predetermined 3D positions of branches of villous trees. The 3D positions were determined prior to histologic sectioning using a recently introduced 3D-microscopic approach. Individual histologic sections of villi were classified by their stromal structures and inter rater variability of these histologic assessments were determined.
Inter rater variability was high and indicates substantial observer influence on the outcome of histologic assessments. Cross-match of villous types with the predetermined positions of villous branches of villous trees revealed substantial mismatch between the outcome of stromal classification and 3D-position of the sectioned villi in the placental villous trees.
Ludwig-Maximilians-University, Department of Anatomy II, Munich, Germany.
Eva
E
Haeussner
Ludwig-Maximilians-University, Department of Anatomy II, Munich, Germany.
Beate
B
Aschauer
University of Cambridge, Department of Physiology, Development and Neuroscience, Cambridge, UK.
Graham J
GJ
Burton
Medical University of Graz, Institute of Cell Biology, Histology and Embryology, Graz, Austria.
Berthold
B
Huppertz
Clinic for Obstetrics and Gynecology, Dritter Orden, Munich, Germany.
Franz
F
Edler von Koch
Ludwig-Maximilians-University, Department of Anatomy II, Munich, Germany.
Jens
J
Müller-Starck
Placental Analytics LLC, Larchmont, USA; New York Methodist Hospital, Department of Obstetrics and Gynecology and Pediatrics, NY, USA.
Carolyn
C
Salafia
Ludwig-Maximilians-University, Department of Anatomy II, Munich, Germany.
Christoph
C
Schmitz
Ludwig-Maximilians-University, Department of Anatomy II, Munich, Germany. Electronic address: hans-georg.frank@med.uni-muenchen.de.
Hans-Georg
HG
Frank
D002824:Chorionic Villi / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D010920:Placenta / Q000033:anatomy & histology*; D011247:Pregnancy
3D structure; Anatomy; Branching pattern; Classification; Placenta; Villous tree