Aging of the Hematopoietic System: Mechanisms, Consequences, and Systemic Interactions.

The aging of the hematopoietic system is central to physiological aging, with profound consequences for immune competence, tissue regeneration, and systemic health. Age-related changes manifest as altered blood cell composition, functional decline in hematopoietic stem cells (HSCs), and deterioration of the bone marrow niche. Beyond hematologic dysfunction, hematopoietic aging acts as a systemic amplifier of age-related diseases through clonal hematopoiesis and inflammatory remodeling. This review integrates recent insights into the mechanisms and systemic impacts of hematopoietic aging, reframing it as a modifiable axis of systemic aging. We highlight emerging rejuvenation strategies-senolytics(definition), metabolic reprogramming, and microbiota-targeted therapies-that aim to restore hematopoietic and immune function, offering promising avenues to improve healthspan(definition) and reduce age-related multimorbidity.