In a groundbreaking study that challenges long-standing beliefs about aging and hair loss, Dr. Rui Yi, a professor of pathology at Northwestern University, has uncovered a novel phenomenon. 

As reported by Gina Kolata in The New York Times in October 2021, this study reveals that the key to understanding hair loss with age might lie in the behavior of stem cells.

The Discovery

Dr. Yi and his team observed something remarkable: Contrary to the accepted hypothesis that stem cells in hair follicles are depleted and die off as part of the aging process.

In aging animals, these stem cells don’t just die; they actively escape from their follicular structures. “It’s a new way of thinking about aging,” commented Dr. Cheng-Ming Chuong, a professor of pathology at the University of Southern California, underscoring the significance of this finding, published in the journal Nature Aging.

Research Methodology and Findings

To observe this phenomenon, Dr. Yi and his graduate student, Chi Zhang, employed a novel approach. They used a long-wavelength laser to monitor the growth of individual hair follicles in mice, marking the follicles with a green fluorescent protein for visibility.

This method allowed them to observe, in real-time, the surprising behavior of stem cells escaping their niches in the follicles as the mice aged.

Implications and Future Directions

This escape of stem cells led to the discovery of two genes, FOXC1 and NFATC1, which were less active in older follicular cells. These genes play a role in keeping stem cells within the follicle. This finding opens up new avenues for potential treatments to prevent hair loss by targeting these genetic pathways.

Expert Perspectives

Charles K.F. Chan, a stem cell researcher at Stanford University, lauded the study as “very important,” recognizing the complex challenge of understanding aging. Sarah Millar, director of the Black Family Stem Cell Institute at the Icahn School of Medicine at Mount Sinai, explained the growth cycle of hair and the role of stem cells, adding context to the importance of this discovery.