Good news! Towards more effective boosting of the immune system with age!
"A new study has discovered why a key immune organ, the thymus, declines with age. The findings could help scientists boost ageing or depleted immune systems one day. ...
“The number of new T cells produced in the body significantly declines after puberty, irrespective of how fit you are. By age 65, the thymus has virtually retired,” ..."
"... A new study has been able to visualise, for the first time, how two cell types drive this ageing process and cause the thymus to lose its function and regeneration abilities over time. ...
In a world-first, the researchers discovered these clusters also formed ‘scars’ in the thymus which prevented the organ from restoring itself after damage. ..."
These cells, which appeared only in the defective thymus of older mice and humans, were found to form clusters around T cell growth areas, impairing the organ’s ability to make these important immune cells.
From the abstract:
"The thymus is essential for establishing adaptive immunity yet undergoes age-related involution that leads to compromised immune responsiveness. The thymus is also extremely sensitive to acute insult and although capable of regeneration, this capacity declines with age for unknown reasons. We applied single-cell and spatial transcriptomics, lineage-tracing and advanced imaging to define age-related changes in nonhematopoietic stromal cells and discovered the emergence of two atypical thymic epithelial cell (TEC) states. These age-associated TECs (aaTECs) formed high-density peri-medullary epithelial clusters that were devoid of thymocytes; an accretion of nonproductive thymic tissue that worsened with age, exhibited features of epithelial-to-mesenchymal transition and was associated with downregulation of FOXN1. Interaction analysis revealed that the emergence of aaTECs drew tonic signals from other functional TEC populations at baseline acting as a sink for TEC growth factors. Following acute injury, aaTECs expanded substantially, further perturbing trophic regeneration pathways and correlating with defective repair of the involuted thymus. These findings therefore define a unique feature of thymic involution linked to immune aging and could have implications for developing immune-boosting therapies in older individuals."
New clue into the curious case of our ageing immune system (original news release)
Fig. 1: Emergence of atypical epithelial populations with age.
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