Mesenchymal stem cells (MSCs) not only possess the basic characteristics of stem cells, including self-renewal and multi-lineage differentiation potential, but also exhibit hematopoietic [1], [2] and immunomodulatory function [3]–[6]. Neonatal tissue is rich in MSCs derived from Wharton’s jelly in the umbilical cord and from the deciduae, which form the maternal part of the placenta. The placentome is customarily discarded as a medical waste, and there is no ethical controversy in obtaining MSCs from this tissue. There may be many similarities between MSCs from the above two sources. Nevertheless, they play different roles during fetal development, and so have their own characteristics. The placenta and fetal membranes function as immunological barriers between the mother and the developing fetus during pregnancy. The placenta can be conceptually divided into the fetal side, consisting of the amnion and chorion, and the maternal side, consisting of the decidua. As placental tissues are conventionally discarded after delivery, these tissues are readily available for research and clinical applications. The decidua is a membrane of maternal origin that plays an important role in immune tolerance, since maternal and fetal immune cells come into direct contact with each other at this site [5]. Wharton’s jelly is the embryonic mucous connective tissue found between the amniotic epithelium and the umbilical vessels; it is a rich source of MSCs [7]. MSCs from Wharton’s jelly (WJ-MSCs) exhibit greater proliferation than adult MSCs from the bone marrow [6].
Most often MSCs are transplanted for tissue repair and regeneration. Due to their immunomodulatory properties, MSCs have garnered increasing research attention in recent years. MSCs have been used for treating graft-versus-host disease [5], [8]–[10]. MSCs from the bone marrow, which were first described by Fridenstein et al. [11] in 1976, were the earliest stem cells to be detected and, currently, are the most used stem cells in clinical trials. However, their limited availability hindered their development in research and clinical applications. The use of neonatal tissue can overcome this shortcoming. In our study, we compared MSCs derived from Wharton’s jelly in the umbilical cord and from the decidual stroma in the maternal-origin placenta to understand their similarities and differences. The morphology and immunophenotype (assessed using flow cytometry) were analyzed. Karyotype analysis was carried out to determine the origin of the MSCs. Growth kinetics were evaluated using the population doubling time (PDT) and cell cycle. Immunosuppressive function was analyzed using mixed lymphocyte culture.