Breast milk may provide longer-term benefits than previously thought, extending even into adulthood. A study at the University of Western Australia found that in mice, stem cells received during infancy from a mother's breast milk were present in several tissues all around the body, including in the brain, blood, kidneys, and pancreas, throughout life.
Some of the stem cells even integrated into organs to become functional cells, including neurons and insulin-producing cells in the pancreas. The findings might suggest a new direction for research on therapeutic uses of stem cells.
Unlike embryonic stem cells - the gold standard of stem cell research - stem cells from breast milk do not present any ethical concerns. They also lack the same capacity for unlimited cell division that embryonic stem cells possess, meaning that they might not induce tumors to form when injected into patients. If they prove to be functional, stem cells from breast milk may even be used in cell therapies and tissue replacement.
The procedure that the researchers, led by Foteini Hassiotou, used involved glowing mice, which were genetically modified to express a gene called tdTomato that causes cells to fluoresce red under ultraviolet light. These mice were mated, and their babies were swapped with the pups of another, unmodified mother mouse. The new pups suckled the modified mouse and, as a result, obtained glowing red stem cells from the breast milk.
These methods, of course, cannot be replicated in humans, so it's not clear yet if the findings apply to humans as well as mice. However, the results of the study are a jumping-off point for future research on human breast milk stem cells and their possible application in stem cell therapies.