Human amniotic membrane: a potential tissue and cell source for cell therapy and regenerative medicine

Abstract

[Abstract] The human amniotic membrane (HAM) is the innermost membrane surrounding the fetus. HAM is a highly abundant and readily available tissue that is becoming appreciated as an alternative to adult bone marrow mesenchymal stem cells (BM-MSCs) useful for cell therapy and regenerative medicine. This tissue provides high efficiency in noninvasive and safe MSC recovery with no intrusive procedures. HAM contains two cell types from different embryological origins: human amnion epithelial cells (hAECs), derived from the embryonic ectoderm, and human amnion mesenchymal stromal cells (hAMSCs), derived from the embryonic mesoderm. hAMSCs and hAECs are immune-privileged cells that can be isolated without the sacrifice of human embryos, avoiding immunological rejection problems and the ethical conflict of using human embryonic stem cells (hESCs). Regarding their immunophenotype, both cell types demonstrate the expression of the common well-defined human mesenchymal and embryonic stem cell markers and the absence of hematopoietic markers. Moreover, both cell populations have similar multipotential for in vitro differentiation into all three germ layers: ectoderm, mesoderm, and endoderm lineages. Indeed, the potential application of amnion-derived cells in a variety of diseases, in particular those associated with degenerative processes, is under clinical or preclinical investigation. The HAM has other biological properties important for tissue engineering, including anti-fibrosis, anti-inflammatory, anti-scarring, antimicrobial, as well as adequate mechanical properties and low immunogenicity. Therefore, amnion allografts are widely applied in ophthalmology, plastic surgery, dermatology, and gynecology. In this chapter, the localization, isolation, characterization, and differentiation potential of amnion-derived cells are discussed. Moreover, the potential clinical applications of either amnion-derived cells or the whole HAM are also reviewed.