New research shows that measuring proteins in the blood may predict both health and lifespan. The research was published in Nature Medicine with support from a grant from Cure Alzheimer’s Fund. Tony Wyss-Coray, PH.D. and a team of scientists have used advances in protein profiling technology to measure thousands of proteins in the plasma throughout the human lifespan in order to evaluate the profiles associated with healthy aging and with disease.
Blood has cells that transport oxygen, fight infectious disease, and carry messenger molecules with information across organ systems. The blood contains hormone-like factors that promote growth and survival; the composition of these factors changes during aging and with disease. The hormone-like factors involved in cell injury, repair, and inflammation increase during aging while those involved in the maintenance and development of tissue decrease with age. Blood tests are beginning to be used as a prognosis for many diseases including cancer, brain trauma, and heart failure, as well as amyloid plaque levels in the brain.
Using a technology called SOMAmer the researcher team measured the levels of nearly 3,000 different plasma proteins from more than 4,000 healthy individuals age 18 – 95. As a key part of the study, the team identified 373 proteins in the blood that consistently changed throughout the lifespan of both mice and humans. Through machine learning techniques, evaluation of these proteins accurately predicted the biological age of the participants in the study. The technology predicted that some individuals were younger than their true chronological age and these individuals were found to be healthier, both cognitively and physically, than subjects who had a different protein profile. The authors hope that this proteomic clock could be applied to identify individuals at risk for disease.
If we look at how the blood changes during aging and in Alzheimer’s disease, could we learn something about the brain?
As we get older, our brains have a harder time with the learning and memory tasks that used to be performed with ease. With age, the connections between neurons break down impairing neuronal communication. During aging, the brain begins to shrink, and neurons die. There is also increased susceptibility to neurodegenerative diseases such as Alzheimer’s disease.
Because the brains of living people cannot be studied in detail, understanding the brain at a molecular level has been difficult. Scientists can perform sophisticated neuroimaging studies and assess cognitive abilities, but it is through an autopsy that most insights into how the brain changes at the molecular level occur during aging.