Research examined the behavior of adult stem cells, it’s about aging and a sense of smell. In normal aging process, older adults repeatedly experience failure in their olfactory function. This results in complete loss of smell because of aging, medication or illness which affects the sense of taste. It is published in the Cell Stem Cell.

Stem cells are undifferentiated, or unspecialized; they are highly potent and able to generate many different types of cells. Embryonic stem cells can give rise to any cell type in the body, while adult or tissue stem cells have a more limited potency. Adult stem cells are responsible for maintaining the structure of the tissue in which they are found and repairing it after injury.

Adult stem cells regenerated in mice with injured nasal tissue. When those adult stem cells were transplanted into other mice, they could regenerate all the different cell types in the nasal tissue, also called the olfactory epithelium. This expansion of the stem cell population improved when the researchers swabbed a pharmaceutical preparation into the nose; the drug combination pushed progenitor cells to remain upstream as adult stem cells.

Yamanaka's approach was designed to replace stem cells lost to aging by inducing cells taken from adult tissues to behave like embryonic stem cells, by forcing them to express four genes that are usually expressed in embryonic stem cells.

The research team from Tufts determined that only two of the four factors used by Yamanaka to artificially reprogram adult cells into iPSCs are critical to the process of pushing the olfactory cells to become more stem cell-like.

Brian Lin said, "We are the first researchers to gain insight into the molecular mechanism responsible for allowing these adult progenitor cells to become more potent. We were intrigued that the process shared such a core similarity with iPSC technology, which provides a potential explanation and natural origin for the mechanism that the scientific community has harnessed to great effect."

Jim Schwob said, "The direct restoration of adult stem cells has implications for many types of tissue degeneration associated with aging, though we are several years away from designing actual therapies based on this work. The olfactory epithelium is a singularly powerful model for understanding how tissues regenerate or fail to do so."

Population of stem cells in the olfactory epithelium, by administering the proper drug as a nasal pray. It is possible to prevent deterioration in the sense of smell.