Researchers develop tool to measure biological age in individual cell types

A new priority research paper, featured as the cover of Aging (listed by MEDLINE/PubMed as "Aging (Albany NY)" and "Aging-US" by Web of Science) Volume 16, Issue 22, was published on December 29, 2024. The paper is titled "Cell-type specific epigenetic clocks to quantify biological age at cell-type resolution."

Researchers from the Chinese Academy of Sciences and Monash University developed a new way to measure biological aging in individual cell types. This new tool offers a more detailed understanding of how cells age, providing insights into diseases such as Alzheimer's and liver pathologies, leading the way for more precise health assessments and targeted therapies.

Biological age refers to how old a person's body is biologically, which may differ from their actual age in years. Typically, biological age is estimated using "epigenetic clocks," which rely on DNA methylation patterns-;chemical marks linked to aging. Standard methods analyze all the cells from a specific tissue at once, making it difficult to understand the aging processes in the different cell types that constitute the tissue.

To address this, researchers Huige Tong, Xiaolong Guo, Macsue Jacques, Qi Luo, Nir Eynon, and Andrew E Teschendorff analyzed DNA samples from human brain and liver tissues to create a new analysis tool. With the help of advanced computer models, they studied changes in DNA methylation in samples from healthy and diseased individuals. By isolating biological aging within specific cell types, the team could better understand how these changes contribute to diseases like Alzheimer's or liver conditions.

The study revealed that certain brain cells, like neurons and glia, age faster in people with Alzheimer's disease, suggesting that the aging of specific cell types plays a critical role in neurodegeneration. In liver diseases, such as fatty liver disease and obesity, the clock for liver cells showed signs of accelerated aging, making it a better tool than previous methods for detecting liver problems.

"We find that neuron and glia specific clocks display biological age acceleration in Alzheimer's Disease with the effect being strongest for glia in the temporal lobe." 

This new approach distinguishes the aging process within individual cell types from changes in the overall composition of cells in a tissue, offering a clearer view of how aging affects each specific cell type. This is crucial for identifying which cells are most affected by aging in certain diseases, guiding the development of targeted therapies.

In conclusion, this study highlights the critical importance of precision in aging research, allowing deeper insights into the aging process and significant advancements in the prevention, diagnosis, and treatment of age-related diseases.