Study offers insight into how long-term inflammation may contribute to cognitive decline

The King's College London study, published in Nature Communications, offers insight into how long-term inflammation may contribute to cognitive decline in disorders such as Alzheimer's disease, aging, depression, and the lingering neurological effects of viral infections.

The scientists discovered that adding a molecule, that is involved in the inflammatory response, to stem cells from the hippocampus prevents the development of new neurons. The formation of new neurons in this region, known as hippocampal neurogenesis, is essential for learning, memory and mood regulation. It is one of the few parts of the human brain where new neurons are made in adults. Altered adult hippocampal neurogenesis is associated with aging, neurodegeneration, and mood disorders such as depression.

The study focused on cytokines, which are chemical signals that are released by the body in response to a threat, such as a viral infection. Cytokines ultimately act as triggers for the rest of the immune response, which helps the body fight the infection. High cytokine levels are also a hallmark of chronic inflammation.

Viral infection has previously been linked to changes in the ability to create new neurons in part of the hippocampus. However, how exactly infection and inflammatory cytokines affect creation of new neurons was previously unknown.