Amniotic Membrane Stem Cell Populations

Abstract

Amnion membrane has long been used to facilitate wound healing and repair. However, the recent recognition that the fetal membranes, both amnion and chorion, contain a variety of cell populations with stem cell or stem cell-like properties has led to renewed interest in the regenerative medicine potential of these tissues that are otherwise regarded as medical waste. There are two main populations of stem cell-like cells in the amnion—amnion mesenchymal stem cells and amnion epithelial cells. While they possess similar properties there are also some important differences that may be important for future clinical applications. Studies using these cells to date have been mainly limited to experimental animal work but have addressed diverse applications such as lung disease, diabetes, neurological disorders, liver disease, ischaemic disorders. It would appear that for most of these applications the cells are not implanting and differentiating into niche lineages to effect organ repair but rather are targeting host immune responses to injury to drive these towards reparative pathways. Specifically, the cells appear to critically modulate host macrophage and T cell responses. Most recently, it has been shown that the cells themselves may not be required to effect repair but that cell-conditioned media may be sufficient. Exploring what cell secreted products effect the reparative actions is now an urgent focus of attention. These insights will likely better direct translation of the experimental research into clinical trials, many of which are poised to begin.