August 10th, 2026
Technically, even very small effects can be classed as rejuvenation if they move the right markers, if they in some way reduce the burden of damage and dysfunction of aging. Exercise probably rejuvenates to some degree, by any reasonable definition. Yet we know the bounds of the possible when it comes to exercise and other widely used interventions, and the outcomes are nowhere near as large as we would like. Fit people are still aging to death, and end up frail in the later stages of life.
In the matter of restoring lost function to the hematopoietic stem cell populations of the bone marrow that are responsible for generating the cells that make up the immune system, there are a number of interventions that have been shown to outperform the effects of exercise in mice. One of the more interesting examples is the results of a single treatment of CASIN, which improves stem cell function globally, improves immune function, and extends life. Restored immune function is an important goal in the treatment of aging, given the sizable influence the immune system has over the course of aging.
Aged hematopoietic stem cells (HSCs) are characterized by increased phenotypic number, decreased self-renewal and long-term reconstitution capacity, myeloid-biased differentiation, and clonal hematopoiesis. In this review, we summarize the life cycle of HSCs, integrate recent advances in understanding the cell-intrinsic and extrinsic mechanisms that drive HSC aging, and highlight innovative rejuvenation strategies that could be harnessed to delay HSC and systemic aging.
