Stem cells hold great therapeutic promise because of their ability to turn into any cell type in the body, including their potential to generate replacement tissues and organs. While scientists are adept at growing stem cells in a lab dish, once these cells are on their own - transplanted into a desired spot in the body - they have trouble thriving. The new environment is complex and poorly understood, and implanted stem cells often die or don't integrate properly into the surrounding tissue. Researchers created a hydrogel several years ago as a kind of a bubble wrap to hold cells together during transport and delivery into a transplant site. "This study goes one step further, showing that the hydrogels do more than just hold stem cells together; they directly promote stem cell survival and integration. This brings stem-cell based therapy closer to reality."
In addition to examining how the stem cells benefit from life in hydrogels, the researchers also showed that these new cells could help restore function that was lost due to damage or disease. The team injecting hydrogel-encapsulated photoreceptors, grown from stem cells, into the eyes of blind mice. Photoreceptors are the light sensing cells responsible for vision in the eye. With increased cell survival and integration in the stem cells, they were able to partially restore vision. "After cell transplantation, our measurements showed that mice with previously no visual function regained approximately 15% of their pupillary response. Their eyes are beginning to detect light and respond appropriately."
In another part of the study, researchers injected the stem cells into the brains of mice who had recently suffered strokes. "After transplantation, within weeks we started seeing improvements in the mice's motor coordination." The team now wants to carry out similar experiments in larger animals, such as rats, who have larger brains that are better suited for behavioral tests, to further investigate how stem cell transplants can help heal a stroke injury.