Molecular mechanisms underlying lineage bias in aging hematopoiesis

Although hematopoietic stem cells (HSCs) have traditionally been thought to possess the ability to give rise to all the mature cell types in the hematopoietic system, this conception of hematopoiesis was typically based on evaluation of hematopoietic output from large numbers of HSCs using transplantation models.   More recent studies evaluating HSCs at the clonal or near-clonal level, both in transplantation studies and during in situ hematopoiesis, have established that individual HSCs can exhibit lineage bias, giving rise to myeloid-biased, lymphoid-biased, or more balanced differentiation, with the prop ortion of myeloid-biased HSCs increasing with age.  This age-associated shift in lineage potential is associated with decreased cellular immunity and increased incidence of diseases with prominent inflammatory components, including atherosclerosis, autoimmunity, neurodegenerative disease, and carci nogenesis.
Source: Seminars in Hematology - Category: Hematology Authors: Source Type: research