Gaby
Researchers at City of Hope found that waistlines expand with age because aging stem cells become more active.
Many people face this age-related change, which can be disheartening. But it’s more than a cosmetic issue. Belly fat speeds up biological aging and slows metabolism, raising the risk of diabetes, heart disease, and other chronic conditions.
Still, exactly how age turns six-pack abs into a soft belly wasn’t clear.
A preclinical study from City of Hope uncovered a cellular reason for the age-related accumulation of belly fat and offered new insight into why our midsections grow as we get older.
The team found that “as people age, they often lose muscle mass and gain fat, even if their weight remains unchanged.” They also found that aging “triggers the emergence of a new type of adult stem cell and ramps up the body’s production of new fat cells, particularly in the abdominal area.”
What Else Did the Team Find?
The team, led by Guan Wang and Haoyan Li, ran experiments in mice and later confirmed the results in human cells. They focused on white adipose tissue (WAT), the fat linked to age-related weight gain, Medical Xpress reports.
Fat cells are known to grow larger with age, but the researchers suggest WAT also expands because the body keeps making new fat cells—potentially giving it near-unlimited growth potential.
To test that idea, they focused on adipocyte precursor cells (APCs) — stem cells in white adipose tissue that mature into fat cells.
First, the team transplanted APCs from young and old mice into a separate group of young mice. APCs from older animals quickly generated a large number of fat cells.
When the researchers transplanted APCs from young mice into older mice, those stem cells did not produce many new fat cells. The results showed that old APCs are programmed to generate new fat cells on their own, regardless of the host’s age.
Using single-cell sequencing, the team compared APC activity in young and old mice. APCs were barely active in young mice but became roughly twice as active in middle-aged mice and began producing 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 team wrote in their report. Understanding these processes will help scientists develop new medical solutions to combat belly fat and improve health later in life.
The study’s results were published in the journal Science.
