Electronic microscopic specifications of decidual spilla in a woman with placenta previa

Abstract

The objective: a study of the electronic microscopic features of the decidual membrane in pregnant women with placenta previa. Materials and methods. 122 pregnant women with atypical location of the placenta were examined and delivered within 36 weeks+6 days and 38-39 weeks of gestation in Kyiv Perinatal Center during 2014–2020. Electronic microscopy of the decidual membrane was performed in 10 pregnant women with placenta previa. Decidual membrane biopsy was performed directly from the site of placenta previa and from the uterine body outside the placenta previa. Results. By placenta previa the endometrial glands penetrate deep into the myometrium in the border zone of the endometrium with the myometrium, some of them lose the basement membrane in the epithelium, and the enlarged tubules of the granular endoplasmic reticulum are located in its cytoplasm. Most of them are without ribosomes, which formed autophagosomes in the cytoplasm or outside it. A large number of dictyosomes were found. In most of the epithelial cells, the plasma membrane is not preserved and the cytoplasm is in direct contact with the myometrium or connective tissue or is lysed.Examination of the decidual membrane in the body of the uterus outside the placenta previa demonstrated that the decidual cells are surrounded by a basement membrane, have a polygonal shape, contain many glycogen inclusions in the form of small dense granules – beta-particles and granules which form the clusters in the form of rosettes – alpha-particles. Their content is washed out of fat inclusions, and the cytoplasm of decidual cells, in the late period of observation, loses the content of trophic inclusions and, accordingly, energy supply. The lumens of blood vessels are filled with electronic dense content or are completely obstructed by accumulations of blood plasma proteins, fibrin, cellular detritus of blood cells, which contributes to the formation of blood clots. The smooth muscle cells of these vessels are compacted and located in the clefts of the basement membranes of epitheliocytes and their own basement membranes. Conclusions. In the decidual membrane directly in the area of ​​placenta previa in the lower segment of the uterus, the foci of decidualization significantly expand and push the endometrial glands into the myometrium. The basement membrane of the endometrial epithelium is lysed, its structural organization is disrupted and its contents are homogenized, which leads to an increase in the permeability of the decidual membrane. Blood-forming elements, in particular leukocytes, cellular detritus and the significant growth of collagen and elastic fibers impede interstitial transport of the intercellular substance that leads to the systemic disorganization of connective tissue, damage of vessels of a hemomicrocirculatory channel and the increase in immunopathological processes. In turn, the loss of the inclusions by the decidual cells leads to a disorder of trophic decidual membrane in the uterine body by placenta previa in the lower segment of the uterus.