According to American scientists involved in the City of Hope research project, waistlines are expanding over the years because aging stem cells are “switching to heightened activity.”
Many people face this age-related change, which can be disheartening. However, this issue is not just about visual appeal. Belly fat accelerates aging and slows metabolism, increasing the risk of developing diabetes, heart problems, and other chronic diseases.
Yet, how exactly age transforms six-pack abs into a soft belly has remained unclear.
The preclinical study from City of Hope has uncovered a cellular reason for the age-related accumulation of belly fat and provided new insights into why our midsections grow as we age.
Researchers noted that “as people age, they often lose muscle mass and gain fat, even if their weight remains unchanged.” They discovered that “aging triggers the emergence of a new type of adult stem cell and enhances the body’s mass production of new fat cells, particularly in the abdominal area.”
What Else Did Scientists Discover?
The team, led by Guan Wang and Haoyan Li, conducted a series of experiments on mice, the results of which were later confirmed in human cells. The scientists focused on white adipose tissue (WAT), which is responsible for age-related weight gain, as reported by Medical Xpress.
While it is well-known that fat cells grow larger with age, the researchers suggested that white adipose tissue also expands “thanks to” the production of new cells. This means it may have unlimited growth potential.
To test their hypothesis, the researchers focused on adipocyte precursor cells (APCs) – a group of stem cells in white adipose tissue that evolve into fat cells.
Initially, the team transplanted APCs from young and old mice into a second group of young mice. The APCs from older animals quickly generated a massive number of fat cells.
However, when the team transplanted APCs from young mice into older mice, the stem cells did not produce many new fat cells. The results confirmed that old APCs are programmed to independently generate new fat cells, regardless of the age of their host.
Using single-cell sequencing, the scientists compared the activity of the APC gene in young and old mice. While barely active in young mice, APCs awakened with double the strength in middle-aged mice and began churning out new fat cells.
“While the ability of most adult stem cells to grow diminishes with age, the opposite occurs with APCs – aging unleashes these cells’ capacity to develop and proliferate,” said Professor Adolfo García-Ocana, a participant in the City of Hope study. “This is the first evidence that our bellies expand with age due to the large number of new fat cells produced by APCs,” he added.
“Our findings highlight the importance of controlling the formation of new fat cells to address the issue of age-related obesity,” the researchers wrote in their report. Understanding these processes will help scientists develop new medical solutions to combat belly fat, thereby improving health in later years.
The study’s results were published in the journal Science.