According to a study, a simple blood can detect a protein called p16INK4a, the molecular biomarker of ageing in humans which is present in cells called T-lymphocytes (T-cells).
In 2004, researchers at the University of North Carolina found that as cells and tissues age, the expression of p16INK4a dramatically increases in most mammalian organs.
Being a tumor suppressor protein, p16INK4a has interested cancer researchers for its potential role in cellular aging and cancer prevention.
And now, the new research has proven that the same biomarker is present in human blood, and is strongly correlated both with chronological age and behaviors like tobacco use and physical inactivity, which are known to accelerate the ageing process.
Now, the researchers have claimed that they have solved technical hurdles to develop a simple blood test to detect p16INK4a expression in T-cells.
"This is a major step toward a practical tool to clinically determine a person's actual molecular, as opposed to just their chronological age," said Dr. Norman Sharpless, the senior author of the study.
The researchers validated the test by obtaining blood from two groups of healthy human volunteers, totaling 170 subjects, who also filled out a questionnaire about current and past health status and health behaviors.
They observed that the expression of the biomarker strongly correlated with the donor's chronological age, and increased exponentially with age.
Besides, increased levels were independently associated with tobacco use and physical inactivity as well as with biomarkers of human frailty.
"We found a very weak correlation between the biomarker and obesity, as measured by body mass index (BMI), despite other data suggesting that caloric restriction slows aging. The data suggest the possibility that reduced exercise may actually be worse with regard to molecular age than a higher BMI," said Sharpless.
He added: "Although we don't know whether this test is a good reflection of cellular age in all types of human tissues, we believe it is a first step toward a better understanding of issues like the suitability of organs for transplantation, how well patients are likely to recover after surgery or the future toxicity of chemotherapy for cancer patients."
The study has been published online ahead of print in the journal Aging Cell.