Phagocytosis of human cytotrophoblast cell invading into decidual tissue in early stage of gestation.

Abstract

To elucidate the mechanism of trophoblastic invasion, further electron microscopic observation of human implantation sites, described in a preliminary paper, were performed. The cytotrophoblast cells invaded decidual tissue have taken in many cells and absorbed many materials. In this paper, the authors specifically report the phagocytotic function of the cytotrophoblast cell. It was clarified by criteria, described in preliminary papers, for judgement of cells composing the feto-maternal junctional zone that almost all cells phagocytized by the cytotrophoblast cells were decidual cells which showed significant ultrastructural changes in various degrees; some cells still had intrinsic features by which the cells could be clearly identified as decidual cell, and some cells were considered as a strongly altered degenerated decidual cells. Moreover, even though these phagocytized cells had not so many lysosome that these cells can autolysis, the cytotrophoblast cells had many lysosome having strong activity of acid phosphatase. After the cytotrophoblast cells contact decidual cells by means of many patterns, the cytotrophoblast cells can phagocytized the inactivated cell and can intracytoplasmically digest the cell actively.