2023-12-06 18:00:04
A study of 5,678 people, led by Stanford Medicine researchers, has shown that our organs age at different ratesand when the age of an organ is especially advanced compared to that of other people of the same age, the person who carries it has a increased risk of both diseases associated with that organ as dying.
About 1 in 5 reasonably healthy adults aged 50 or older has at least one organ that is aging at a very rapid rate, according to the study.
The positive part is that it is possible for a simple blood test can indicate which organs in a person’s body, if any, are aging rapidly, guiding therapeutic interventions long before clinical symptoms manifest.
«We can estimate the biological age of an organ in an apparently healthy person. That, in turn, predicts a person’s risk of suffering from diseases related to that organ,” says the study’s lead author, Tony Wyss-Coray, PhD, doctor and professor of neurology.
Hamilton Oh and Jarod Rutledge, graduate students in Wyss-Coray’s lab, are lead authors of the study, which is published this Wednesday in Nature.
Biological VS Chronological Age
“Numerous studies have produced single figures that represent the biological age of individuals (the age implied by a sophisticated set of biomarkers) as opposed to their chronological age, the actual number of years that have passed since their birth,” notes Wyss-Coray. , who is also director of the Phil and Penny Knight Initiative for Brain Resilience.
The new study went a step further and obtained different numbers for each of 11 key organs, organ systems or tissues: heart, fat, lung, immune system, kidney, liver, muscle, pancreas, brain, vascular system and intestine .
“When we compared the biological age of each of these organs for each individual with their counterparts among a large group of people without obvious serious diseases, we found that 18.4% of people aged 50 years or older had at least one organ that aged significantly faster than average. And we found that these individuals have a higher risk of disease in that particular organ in the next 15 years,” says Wyss-Coray.
Only about 1 in 60 people in the study had two organs aging at that rapid rate. But, Wyss-Coray warns, “they had 6.5 times the risk of mortality than someone without any clearly aged organs.”
Using commercially available technologies and an algorithm of their own design, they began by checking the levels of almost 5,000 proteins in the blood of just under 1,400 healthy people between 20 and 90 years old, but mainly in middle and late stages of life, and noted all proteins whose genes were four times more activated in one organ compared to any other organ. They found almost 900 organ-specific proteins, which they reduced to 858 for reliability reasons.
To do this, they trained a machine learning algorithm to guess the age of people depending on the levels of those almost 5,000 proteins. The scientists verified the accuracy of the algorithm by evaluating the ages of approximately 4,000 other people who were somewhat representative of the US population.
They then used the proteins they had identified to zero in on each of the 11 organs they had selected for analysis, measuring the levels of each organ-specific protein within each individual’s blood.
While there was a modest synchrony of aging between separate organs within any person’s body, that person’s individual organs largely followed separate paths along the aging pathway.
For each of the 11 organs, Wyss-Coray’s team came up with an ‘age gap’: the difference between an organ’s actual age and its estimated age based on the algorithm’s calculations based on proteins specific to each organ. The researchers found that age differences identified for 10 of the 11 organs studied (with the sole exception of the intestine) were significantly associated with the future risk of death from all causes during 15 years of follow-up.
Having an accelerated aging organ carried a 15% to 50% higher risk of mortality in the following 15 years, depending on the organ affected.
People with accelerated cardiac aging but who initially had no active disease or clinically abnormal biomarkers had a 2.5 times higher risk of heart failure than people with normally aging hearts, the study showed.
Those with older brains were 1.8 times more likely to show a cognitive decline in five years than those with young brains. Accelerated aging of the brain or vascular system (either) predicted the risk of Alzheimer’s disease progression as well as the currently best-used clinical biomarkers.
There were also strong associations between a kidney extreme aging score and hypertension and diabetes, as well as between a cardiac extreme aging score and both atrial fibrillation and heart attack.
“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 could find organs that are undergoing accelerated aging and perhaps we can treat people before they get sick«Advances Wyss-Coray.
Identifying the organ-specific proteins that best indicate excessive organ aging and, consequently, elevated disease risk could also lead to new drug targets, he notes.
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