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The study, published this week in Nature, identifies a previously unknown subset of blood stem cells that are shaped by past inflammatory events. These cells appear to accumulate over time and may influence how the immune system functions later in life.
Blood stem cells, found in the bone marrow, are responsible for producing all the body’s blood and immune cells. They must carefully balance two roles: generating new cells when needed – such as during infection – and preserving a stable pool of stem cells over decades.
While blood stem cells respond to short-term inflammation by stimulating production of more blood cells, repeated or chronic inflammation causes them to become dysfunctional and depleted. Inflammation has also been linked to stem cell ageing and to “clonal haematopoiesis” – an age-related condition where mutated blood stem cells expand over time, associated with a higher risk of leukaemia and other blood cancers. However, it has remained unclear precisely how human blood stem cells respond to inflammatory stress over time.
Researchers from the Vyas Group in the MRC Weatherall Institute of Molecular Medicine at the University of Oxford collaborated with the Dick and Xie labs at the University of Toronto and UHN’s Princess Margaret Cancer Centre to investigate how blood stem cells respond to and recover from inflammation. The team used experimental models alongside analysis of human bone marrow samples to show that blood stem cells do not respond uniformly. Instead, they identified two distinct groups.
Read the full story in the MRC Weatherall Institute of Molecular Medicine website.