Scientists Discover New Type of Stem Cell That Triggers Belly Fat Accumulation with Age

Many people notice their waistline expanding with age, even when overall weight remains stable. Until now, the underlying biological cause for this shift in fat distribution was unclear. A team led by City of Hope, in collaboration with UCLA scientists, has uncovered a key mechanism.

Published in the journal Science, the study focused on adipocyte progenitor cells (APCs), a type of stem cell found in fat tissue. In experiments with mice, APCs from older animals were transplanted into young mice, resulting in a large number of new fat cells. Conversely, when APCs from young mice were placed into older mice, few new fat cells formed. This indicates that the fat-producing capacity is intrinsic to the aged APCs themselves.

Using single-cell RNA sequencing, the researchers identified that with aging, some APCs transform into a new stem cell population they named committed preadipocytes, age-specific (CP-As). These cells appear only during aging and are highly efficient at creating new fat cells. The study also pinpointed a key signaling pathway – leukemia inhibitory factor receptor (LIFR) – which in older mice drives CP-As to proliferate and develop into fat cells.

To test relevance in humans, the team analyzed tissue samples from people of different ages using the same sequencing technique. They found cells closely resembling CP-As, which were more abundant in middle-aged individuals. These human cells also showed a strong ability to generate new fat cells.

The discovery opens up potential new targets for treating age-related obesity. Future research will track CP-As in animal models, investigate their behavior in humans, and explore ways to block or eliminate them to prevent belly fat accumulation.