Biological characteristics of mesenchymal stem cells from adult and extraembryonic tissues.
Study of amniotic membrane-derived mesenchymal and epithelial stem cell potential.
Mesenchymal stem cells from amniotic membrane: establishment of in vitro model for angiogenic differentiation evaluation.
Serum-free culture approach for stem cell-based therapy.
Application of amniotic membrane stem cells for in vitro pancreatic islet building.
Evaluation of tolerogenic molecules in Placental stem cell-mediated immunomodulation.
The amniotic membrane - the innermost layer of fetal membranes, is made up of two cell constituents, namely an epithelial layer, from which amniotic epithelial cells (AECs) may be obtained, and a connective stroma, from which mesenchymal cells (AM-MSCs) can be isolated. The former cell population is able to acquire both phenotype and functionality as secreting cells, the latter is a candidate for the in vitro engineering of pancreatic islets on the basis of its angiogenic potential and their trophic and immunomodulatory properties. Both amniotic-derived cell populations have a well-known differentiation potential, as they may be induced to differentiate as adipocytes, osteocytes, chondrocytes, cardiomyocytes, hepatocytes and vascular cells. In particular, the ability of AM-MSCs to differentiate in angiogenic cells may be exploited to supply the vascular moiety for the engineered pancreatic islets to be transplanted. Grafting pancreatic islets obtained by in vitro differentiation of amnion-derived stem cells is a well-grounded alternative to grafting donor-derived islets, as it possibly outcomes most limitations of such methodology. In fact, the amniotic membrane is an attractive source of stem cells, since it is widely available, it is generally discarded and its utilization is devoid of ethical problems. Moreover, grafts of amniotic-derived cells do not cause rejection in the host, since they are endowed of interesting immunomodulatory properties, namely, they can inhibit the activation and the proliferation of T, B, and Natural Killer cells and can block the activation and the maturation of dendritic cells, while activating regulatory T cells. Because of this, amnion-derived stem cells negatively modulate the immune response and determine a tolerogenic effect, thus reducing the risk of post-transplantation rejection.
Amniotic membrane-derived cells, alone or combined with native endocrine progenitors, may allow the development of novel therapeutic tools for diabetes.