A new study published in Cell on July 25 sheds light on how the human body undergoes distinct biological shifts as it ages, pinpointing a major transition around the age of 50.

The research, led by Guanghui Liu of the Chinese Academy of Sciences, provides one of the most comprehensive analyses to date of how proteins evolve across different organs over time.

Rather than progressing gradually, the ageing process appears to involve sudden accelerations, according to the findings.

By examining tissue samples from 76 individuals aged 14 to 68 who died from accidental brain injuries, the team identified key molecular changes across eight major organ systems, including the cardiovascular and immune systems.

Ageing Pivot

One of the most notable shifts occurred in the aorta, where a specific protein was found to trigger signs of premature ageing when introduced into mice.

Liu and his colleagues observed significant changes in protein expression between the ages of 45 and 55, reinforcing the idea that midlife may represent a turning point in the ageing process.

The study also points to earlier signs of ageing in the adrenal gland, around age 30, indicating that different organs age at different rates.

Liu suggests that blood vessels may play a central role in transmitting age-promoting molecules throughout the body, acting as "a conduit" for systemic ageing.

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While other studies have proposed various ages, such as 44, 60, or even 80, as potential points of accelerated ageing, discrepancies may stem from differences in sample types, populations, and methodologies.

Liu believes that as more detailed longitudinal data become available, researchers will begin to identify common molecular patterns.