The Hematopoietic stem cell population resident in bone marrow is responsible for generating blood cells and immune cells. Like all stem cell populations, their activity alters and declines with aging. This is one of the causes of the progressive disarray of the immune system in older individuals. If we want to rejuvenate the immune system, then restoring the youthful activity of hematopoietic stem cells is one of the items on the to-do list, alongside regrowth of the thymus, and clearing out the accumulation of exhausted, senescent, and misconfigured immune cells.

The protein osteopontin appears to have a sizable role in maintaining the hematopoietic stem cell population, but levels fall in older individuals. Researchers have demonstrated, in mice, that restoring high levels osteopontin can also restore a significant degree of hematopoietic stem cell activity. This is promising because it is comparatively simple to achieve and package as a therapy, but equally it isn't addressing whatever root causes underlie this narrow view of the picture. The open access paper here continues the investigation of osteopontin in the context of hematopoietic aging in mice, adding further evidence for its relevance.

Link: https://doi.org/10.1038/s41598-018-21324-x