It has been a long held belief in the scientific community that nerve cells, or possibly the heart, are the oldest cells in the body. This is due to the fact that the brain and heart are the first organs that begin to develop in the womb. Nerve cells have an average lifespan of approximately 80 years without the need of generating new cells. It has been difficult to determine the approximate age of other organs such as the liver and pancreas in the body until now.

Dr. Rafael Arrojo e Drigo and Dr. Martin Hetzer, scientists at the Salk Institute, have discovered a population of cells that reside in the mouse brain, liver, and pancreas that have extremely long lifespans. In some cases, some of these cells were the same age as the animal they were found in. The scientists used a complex labeling and imaging procedure to determine cell age in a mouse model.

Furthermore, the scientists also found that the brain, liver, and pancreas in the mice contain a mixture of “old” and “young” cells, like a mosaic painting composed of small, different colored pieces. They called this phenomenon age mosaicism, referring to the population of identical cells that could only be distinguished by lifespan.

Their method could be applied to other types of tissue in the body, which could provide valuable information, such as the lifelong function of non-dividing cells and how cells lose control over the quality and integrity of important cell structures during aging. The answers to these questions play a key role in understanding ways to prevent the age-related degeneration of organs, such as the brain in Alzheimer’s Disease or the pancreas in Type II Diabetes.

In a press release, Dr. Hetzer is quoted as saying that,

“Determining the age of cells and subcellular structures in adult organisms will provide new insights into cell maintenance and repair mechanisms and the impact of cumulative changes during adulthood on health and development of disease. The ultimate goal is to utilize these mechanisms to prevent or delay age-related decline of organs with limited cell renewal such as the brain, pancreas and heart.”

The full results of the study were published in Cell Metabolism.

You can also see a youtube video below of Dr. Rafael Arrojo e Drigo and Dr. Martin Hetzer discussing their findings.