Reversal of experimental diabetes in mice by transplantation of neo-islets generated from human amnion-derived mesenchymal stromal cells using immuno-isolatory macrocapsules.

BACKGROUND AIMS: The ethical and biologic limitations with current sources of stem cells have resulted in a quest to look for alternative sources of multipotent stem cells of human origin. Amniotic membrane is of interest as a source of cells for regenerative medicine because of its ease of availability, plasticity and inexhaustible source that does not violate the sanctity of independent life. Although researchers have shown the stem cell-like potential of human amniotic epithelial cells, the mesenchymal part of amnion has remained less explored.
METHODS: We established a long-term culture of mesenchymal-like stem cells derived from full-term human amniotic membrane and their differentiation into functional pancreatic lineage.
RESULTS: The amnion-derived mesenchymal-like stem cells expressed various mesenchymal markers and demonstrated multilineage differentiation capacity. We also observed that these cells could form islet-like clusters (ILC) on exposure to serum-free defined media containing specific growth factor and differentiating agents. Differentiated ILC showed expression of human insulin, glucagon and somatostatin by immunocytochemistry, while quantitative reverse transcription/real-time-polymerase chain reaction (qRT-PCR) data demonstrated the expression of insulin, glucagon, somatostatin, Ngn3 and Isl1. Moreover, encapsulation of the ILC in polyurethane-polyvinyl pyrrolidone macrocapsules and their subsequent transplantation in experimental diabetic mice resulted in restoration of normoglycemia, indicating their ability to respond to high glucose without immunorejection.
CONCLUSIONS: Our results demonstrate that amnion-derived mesenchymal stromal cells can undergo islet neogenesis, indicating amnion as an alternative source of islets for cell replacement therapy in diabetes.