Ultrastructural features of a human placenta with acute chorioamnionitis

Abstract

Portions of several human placentas were processed for light and transmission electron microscopy at the OSU‐CHS electron microscopy lab. Such placentas were characterized as 120g with acute placental abruption, acute chorioamnionitis, increased fetal nucleated red blood cells, villous edema and focal acute intravillous hemorrhages. In our study of the placenta, we were able to define the various parts of the placenta: decidual basal plate, chorionic plate, and chorion frondosum. The chorionic plate is the extra‐embryonic mesoderm of the chorion, bordering the amnionic cavity and lined by the amnion. The chorionic plate represents the embryonic contribution to the placenta. The chorionic plate is the site of histological abnormalities or pathology in these cases. This area was infiltrated with structures having a dark center and a clear surrounding area as revealed by light microscopy. These structures varied in size from 2–4 μm. Macrophages and neutrophils contained several dense spherical structures ranging in size from 0.2–0.5 μm. Several aggregates of these dense spherical bodies were observed. Some larger granular vesicles measured about l μm in size. Literature studies indicate a strong correlation with stages of the parachlamidiae organism. Further ultrastructural and histochemical analysis of these placental structures is currently in progress. OSU‐CHS Intramural Funding