Using a blood test to determine the biological age of a person’s organs could help treat them before they get sick, as well as predict the progression of conditions such as Alzheimer’s disease, researchers have suggested.
A study by academics in the US found that people whose organs age faster than the rest of their body have a greater risk of developing diseases in that particular organ within 15 years.
The team, led by academics from Stanford University in California, used machine learning to determine the protein levels in human blood.
The study focused on 11 organs, organ systems or tissues, including the brain, heart, lung, kidney, liver, pancreas and intestine, as well as the immune system, muscle, fat and vasculature.
To train their algorithm, the team checked the levels of nearly 5,000 proteins in the blood of 1,398 healthy patients at Knight Alzheimer’s Research Center. They ranged in age from 20 to 90, but were mostly in the middle to late stages of life.
Researchers marked all the proteins in which the genes were activated four times more in one organ compared to others. They found 858 organ-specific proteins and trained the algorithm to guess a person’s age based on them.
The study’s senior author, Tony Wyss-Coray, a professor of neurology and the DH Chen Professor II at Stanford University, said: “We can estimate the biological age of an organ in an apparently healthy person. This predicts in turn, a person’s risk for disease related to that organ.”
Overall, the team tested their algorithm on 5,676 patients in five cohorts. The study room, published in Nature, revealed that nearly 20% of patients showed strongly accelerated aging in one organ, while 1.7% showed aging in multiple organs. Researchers said that accelerated organ aging carries a 20%–50% higher risk of death.
Those with accelerated cardiac aging were 250% more likely to have heart failure, while accelerated brain and vascular aging may better predict Alzheimer’s progression than the best current blood-based biomarker.
Wyss-Coray said: “If we can reproduce this finding in 50,000 or 100,000 individuals, it will mean that by monitoring the health of individual organs in apparently healthy people, we may be able to find organs that show accelerated aging in people’s bodies undergo, and we might be able to treat people before they get sick.”
Commenting on the study, Dr Leah Mursaleen, the head of research at Alzheimer’s Research UK, said: “The diseases that cause dementia, such as Alzheimer’s, can start in the brain decades before symptoms appear.
“New treatments on the horizon have been shown to work only in the early stages of Alzheimer’s disease, so we need to find simple methods to accurately identify those most at risk of developing the disease.
“This study suggests that looking at what’s in our blood can provide an important ‘window’ to look at what’s happening deeper in our body – including at the level of individual organs such as the brain.”
Mursaleen said this shows markers in the blood can measure brain and blood vessel aging and potentially be used to predict Alzheimer’s progression and its progression.
“While this science is at an early stage, it has the potential to add to our growing toolkit of blood-based detection methods, many of which are moving closer to routine use,” she said. “It is likely that we will see the first blood tests for Alzheimer’s arrive on the NHS within the next five years.
“Developing even more accurate and less invasive methods to detect signs of age-related diseases, including the earliest signs and progression of Alzheimer’s disease, will bring us closer to curing them. Further work in this area is needed to develop and validate tools like this, to help us get a step ahead of dementia.”
