Organ-specific aging clocks measure each organ separately

The review in Nature Aging discusses how aging clocks have evolved from a single whole-body measurement of biological age into organ-specific readouts. These newer clocks combine data from genomics (reading the complete genetic information), imaging techniques, and other measurements to calculate a separate aging rate for each organ.

Classical aging clocks measure chemical changes to DNA, known as methylation. They produce an estimate of the biological age of the whole body. But that estimate conceals large differences between organs. Some organs age faster than others, and that rate varies between individuals. This has direct consequences for disease risk. A kidney ageing faster than expected predicts different health problems than a brain doing the same.

More detail, more insight into disease

Organ-specific clocks provide information that whole-body clocks cannot. They reveal which organs are most vulnerable in a given individual. This opens the possibility of targeting preventive measures or treatments more precisely. If someone’s heart is biologically ten years older than the rest of the body, cardiovascular risks are already present before any symptoms appear.

The researchers also note limitations. The clocks are not yet standardised, which makes comparison across studies difficult. And for some organs, finding measurement methods applicable to large populations remains a challenge.

Directions for future research

Researchers are now prioritising clocks that combine multiple data types, such as blood measurements together with imaging of the organ itself. They are also seeking clocks sensitive to changes from lifestyle or treatment, so they can measure not just aging but the effect of intervention. Organ-specific clocks are therefore a potentially useful tool for both research and, eventually, clinical practice.

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