Reevaluation of Cell and Tissue Biological Age Determination Based on Epigenetic Modifications

Researchers have recently discovered that determining the biological age of cells and tissues based on epigenetic modifications may not be as accurate as previously believed. Our cells carry a genetic code that directs the production of essential proteins for survival. Over time, small changes occur in this genetic code, acting as 'genetic switches' that influence how cells interpret these instructions without altering the code itself.

The biological age of our cells and tissues is commonly determined by adding up these changes. However, recent research has shown that these changes can fluctuate throughout the day. This means that tests based on a single tissue sample may not provide the most precise estimate of biological age.

In a study conducted over 72 hours, researchers examined multiple blood samples from a 52-year-old man, analyzing 17 different epigenetic clocks within each sample of white blood cells. They observed significant variations in 13 out of the 17 epigenetic clocks throughout the day, with cells appearing 'younger' in the early morning and 'older' around midday. These variations were equivalent to approximately 5.

5 years' worth of changes, highlighting the importance of considering the time of day when assessing biological age. According to statistician Karolis Koncevičius from Vilnius University and colleagues, most aging studies utilizing epigenetic clocks focus on whole blood as the tissue of interest. However, research has shown that counts and proportions of white blood cell subtypes fluctuate throughout the day.

This suggests that a single epigenetic test at a specific time may not provide an accurate reflection of biological age. While studying samples from a single individual allowed the researchers to focus on specific changes, they also observed age variations when analyzing blood samples from a small group over a five-hour period. This suggests that variations in epigenetic clocks may be influenced by factors such as the presence of different white blood cell types in the blood at different times of the day.

To obtain a more accurate assessment of cellular age, future studies may need to collect multiple samples at different times of day. A comprehensive analysis of the epigenetic age range could enhance predictions of the risk of age-related conditions in individuals. In conclusion, determining the biological age of cells and tissues based on epigenetic modifications is a complex process that requires careful consideration of factors such as the time of day and variability in white blood cell types.

By conducting comprehensive studies that take these factors into account, researchers can gain a better understanding of cellular aging and its implications for age-related diseases.