An analysis of hundreds of biological features strengthens the evidence that some organs and body systems can age faster than others. Tracking the biological age of different parts of the body could help doctors predict the onset of disease more accurately.
We already knew that the condition of cells in the body can be interpreted to give someone a biological age that is older or younger than their age measured in years. In other words, cell condition – which varies depending on genetic and lifestyle factors – determines the pace of the ageing process.
Now, work by Brian Kennedy at the National University of Singapore and his colleagues supports the idea that the various organs and systems in the body – such as the cardiovascular or immune system – can age at different rates within the same individual.
“It confirms previous studies that there are diverse ageing rates among organs and systems, and people’s ageing patterns are different,” says Wenyu Zhou at Tempus, a precision medicine company based in Chicago. “This further calls for personalised health assessments that holistically consider various ageing processes.”
Kennedy’s team collected stool and blood samples from about 480 people aged between 20 and 45 and measured a total of 403 biological features in each individual.
The team classified these biomarkers into nine categories to assess the biological age of the kidneys, liver, gut microbiome, cardiovascular system, immune system, metabolic system and sex hormone system. The team also assessed biological age using physical fitness tests and by analysing photographs of participants’ faces.
Out of the nine systems and organs assessed, the biological age of an individual’s cardiovascular system correlated the most with the people’s age in years – their “chronological age”. The biological age of the gut microbiome showed the weakest link with chronological age. Meanwhile, the biological age of the liver and sex hormone systems varied the most between individuals. This confirmed that distinct parts of the body have different biological ages.
The team also discovered that the biological age of the liver could be used to predict which people had non-alcoholic fatty liver disease – a risk factor for type 2 diabetes – and the severity of the condition. This suggested that tracking the biological ages of individual organs could help predict disease risk in those areas.
“There are still many steps before translating the findings to real-world applications,” says Zhou. For instance, it is still unclear if there are interventions that could slow down the ageing process for a specific organ or system, she says.
Journal reference: Cell Reports, DOI: 10.1016/j.celrep.2022.110459
Article amended on 22 March 2022
We clarified Wenyu Zhou’s affiliation
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