Scientists from the University of Geneva (UNIGE) have found that some organs, such as the liver and kidneys, age faster than others due to the active accumulation of mutations in their DNA. The results are published in the journal Cell.
Scientists explained that not all organs and tissues age at the same rate. Aging, characterized by an increase in cells that are unable to divide and have lost their functions, affects the liver or kidneys faster than the skin or intestines. To find out what mechanisms underlie this effect, scientists studied the organs and tissues of laboratory mice.
The scientific community generally believes that aging is caused by damage to genetic material (DNA) that accumulates in the body with age. DNA molecules contain coding regions (genes that code for proteins) and non-coding regions that participate in mechanisms that regulate or organize the genome.
Errors that occur in coding regions are detected when genes are activated. Errors in non-coding regions occur during cell renewal, which requires a new copy of the genome to be created each time through DNA replication. However, cell renewal occurs at different rates depending on the type of tissue or organ.
The researchers specified that tissues and organs that are in constant contact with the external environment, such as the skin or intestines, renew their cells (and therefore reproduce their DNA) more often than once or twice a week. Liver and kidney cells replicate themselves only a few times a year. Because of this, damage accumulates in their DNA, wearing out the organs. This process “gains momentum” in old age.
Scientists hope that their discovery will eventually lead to new therapies that “rejuvenate” organs, most likely by correcting DNA errors before replication begins.
