Which Organs of Yours are Ageing Faster? Scientists can Answer With Blood Tests to Facilitate Early Care

Ageing is a cellular and physiological process, often expressed by the onset of organ-specific disorders, like the weakening of the heart or the bones or the beginning of dementia or any other such issues. With normal ageing, some organs may start manifesting the disorders, while others remain on track. Researchers working on the science of ageing have unveiled many aspects of the process. But imagine where some blood tests, among people in or above their 50s, can tell about symptoms of fast ageing of some organs while others remain alright. Scientists now have a clue in this direction.

In a recent research paper published in Nature, scientists from Stanford University and other institutions claim they can monitor 11 crucial body organs like the heart, brain and lungs. With blood tests, they can predict which organ/organs are ageing faster than others.

Experts opine that this may facilitate early care. For example, if a person's heart is on the track of faster ageing than their other organs, this can be considered to start heart care. Moreover, in their research, the scientists claimed to have found that having one organ with unusually fast ageing increases the risk of premature death.

All 11 organs that the researchers studied can be subject to fast ageing. Moreover, among one-fifth of more than 5600 participants, the signs of accelerated ageing were present for at least one organ. The research suggests these organs are linked to a higher disease prevalence.

How did they do it? By combining blood-protein analyses with computer modelling techniques known as machine learning. Leaving the complicated computer technique aside, let us directly come to proteins in the blood and how they helped the researchers determine what they found.

Previous studies, like the one published in Cell early this year, identified certain hallmarks of ageing at the cellular level. These include the accumulation of damages and mutations (mutations are random changes) that occur in the DNA and also the changes in the epigenome. The epigenome is the collection of chemical compounds and proteins attached to DNA and direct actions like controlling the production of proteins or turning genes on or off, etc.

With the advancing technologies, especially in computer sciences, researchers could develop algorithms over the past decade exploiting this information to determine the biological age of a person, which can be different from the chronological age (or the age according to date of birth).

In addition to these, ageing also has another hallmark—a shift in the production of proteins within the cells. In the latest research with Hamilton Oh of Stanford University as the first author, the researchers analysed over 5000 proteins in the blood plasma (The straw-coloured component of blood where blood cells are absent but have proteins and other constituents) from around 1400 adults.

Among these proteins, they had 850 originating mainly from a single organ. Feeding these into a computer model, they could predict a person's age from the levels of the proteins. They validated the computer model with blood samples of another 4000 participants.

The analyses showed that an organ's biological age is linked to disease risk. Nearly 2% of the participants showed accelerated heart ageing manifested in the blood proteins related to heart ageing. Moreover, these people's blood proteins differ substantially from others of the same age. The researchers found that premature hearts are linked to a 250% increased risk of heart failure.

Commenting on the findings, Hamilton Ho was quoted to have said in an article about the research by Max Kozlov and published in Nature, "Tests for proteins related to organ age could help researchers to develop treatments for age-related health problems and could also guide personalised treatment plans. Physicians already monitor patients' levels of some proteins, and the authors' test would be expanding their toolkit."