Stem cells in the blood can retain a molecular 'memory' of inflammation that may increase the risk of age-related disease, according to a new study led by researchers at the University of Toronto and the University of Oxford. The study is published today in Nature.
The researchers found that some blood stem cells can hold a durable imprint of inflammatory stress long after the initial trigger has passed. This "inflammatory memory" may accumulate across a lifetime, contributing to differences in how people age, recover from severe infection, and develop blood-related conditions.
Blood stem cells sit at the top of the blood and immune system, producing the many cell types that the body needs throughout life including immune cells that respond to infection and injury. While inflammation is essential for fighting infection and repairing damage, repeated or severe inflammatory stress can also have lasting effects on health.
The study identifies a distinct type of blood stem cell, now termed HSC-iM (haematopoietic stem cell inflammatory memory), which showed lasting molecular changes following inflammatory challenge. The researchers drew on experimental models of inflammation and recovery, single-cell genomic technologies to identify stem cells carrying signals associated with inflammation, ageing, severe infection, sickle cell disease, and clonal haematopoiesis. Clonal haematopoeisis is an age-related condition in which some blood stem cell clones expand disproportionately, raising the risk of blood cancers and other chronic diseases.
Read the full story on the Nuffield Department of Population Health website.