Bonemarrow Age

When compared to younger patients, the bone marrow of older patients has a higher quantity of fat and a reduced overall mass, which limits the functional reserve of hematopoietic cells.  In addition, hematopoietic progenitor cell diversity and the response to stimulatory cytokines (eg, stem-cell factor, granulocyte macrophage colony-stimulating factor) are also impaired, thereby limiting the generation of new cells in response to stress.  Because of these changes, older individuals cannot rapidly generate new blood cells.