||Researchers at the University
of Pennsylvania School of Medicine have found that hair follicles
in adult mice regenerate by re-awakening genes once active
only in developing embryos.
||In this study, researchers found that
wound healing in a mouse model created an “embryonic
window” of opportunity. Dormant embryonic molecular
pathways were awakened, sending stem cells to the area of
injury. Unexpectedly, the regenerated hair follicles originated
from non-hair-follicle stem cells.
||These findings provide unequivocal evidence
for the first time that, like other animals such as newts
and salamanders, mammals have the power to regenerate.
||These findings are published in the May
17 issue of Nature.
A note from George Cotsarelis to individuals interested in treatments based on this research (posted June 2009) :
Thank you for your interest in my research. Rest assured that we are continuing our work on hair follicle stem cells and hair follicle regeneration in the hopes of better understanding hair growth and developing treatments for hair loss. The Follica website (http://www.follicabio.com/) will have information regarding upcoming clinical trials. We are not performing any clinical trials at this time.
(PHILADELPHIA) – Researchers at the University
of Pennsylvania School of Medicine have found that hair
follicles in adult mice
regenerate by re-awakening genes once active only in developing
embryos. These findings provide unequivocal evidence for the first
time that, like other animals such as newts and salamanders, mammals
have the power to regenerate. These findings are published in the
May 17 issue of Nature.
Growth of regenerated hair follicles over
45 days. Arrow indicates hair shaft.
Click on thumbnail
to view full-size image
A better understanding of this process could lead to novel treatments
loss, other skin and hair disorders, and wounds.
“We showed that wound healing triggered an embryonic state
in the skin which made it receptive to receiving instructions from
wnt proteins,” says senior author George
Associate Professor of Dermatology. “The wnts are a network
of proteins implicated in hair-follicle development.”
Researchers previously believed that adult mammal skin could not
regenerate hair follicles. In fact, investigators generally believe
that mammals had essentially no true regenerative qualities. (The
liver can regenerate large portions, but it is not de
some of the original liver has to remain so that it can regenerate.)
In this study, researchers found that wound healing in a mouse
model created an “embryonic window” of opportunity.
Dormant embryonic molecular pathways were awakened, sending stem
cells to the area of injury. Unexpectedly, the regenerated hair
follicles originated from non-hair-follicle stem cells.
“We’ve found that we can influence wound healing with
wnts or other proteins that allow the skin to heal in a way that
has less scarring and includes all the normal
structures of the skin, such as hair follicles and oil glands, rather than just a
scar,” explains Cotsarelis.
By introducing more wnt proteins to the wound, the researchers
found that they could take advantage of the embryonic genes to
promote hair-follicle growth, thus making skin regenerate instead
of just repair. Conversely by blocking wnt proteins, they also
found that they could stop the production of hair follicles in
Increased wnt signaling doubled the number of new hair follicles.
This suggests that the embryonic window created by the wound-healing
process can be used to manipulate hair-follicle regeneration, leading
to novel ways to treat hair loss and hair overgrowth.
These findings go beyond just a possible treatment for male-pattern
baldness. If researchers can effectively control hair growth, then
they could potentially find cures for people with hair and scalp
disorders, such as scarring alopecia where the skin scars, and
This research was funded in part by the National
Institute of Arthritis, Musculoskelatal and Skin Diseases and
the Pennsylvania Department
of Health. Other co-authors in addition
to Cotsarelis are Mayumi Ito, Zaixin Yang, Thomas Andl, Chunhua
Cui, Noori Kim, and Sarah E. Millar, all from Penn.
Cotsarelis and Ito are listed as inventors on a patent application
related to hair-follicle neogenesis and owned by the University
of Pennsylvania. Cotsarelis also serves on the scientific advisory
board and has equity in Follica, a start-up company that has licensed
the patent from the University of Pennsylvania. Cotsarelis was
also a co-founder of Follica.
PENN Medicine is a $2.9 billion enterprise
dedicated to the related missions of medical education, biomedical
research, and high-quality patient care. PENN Medicine consists
of the University of Pennsylvania School of Medicine (founded in
1765 as the nation's first medical school) and the University of
Pennsylvania Health System.
Penn's School of Medicine is ranked #2 in the nation for receipt
of NIH research funds; and ranked #3 in the nation in U.S. News
& World Report's most recent ranking of top research-oriented
medical schools. Supporting 1,400 fulltime faculty and 700 students,
the School of Medicine is recognized worldwide for its superior
education and training of the next generation of physician-scientists
and leaders of academic medicine.
The University of Pennsylvania Health System includes three hospitals,
all of which have received numerous national patient-care honors [Hospital
of the University of Pennsylvania; Pennsylvania Hospital, the nation's
first hospital; and Penn Presbyterian Medical Center]; a faculty practice
plan; a primary-care provider network; two multispecialty satellite
facilities; and home care and hospice.
Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $7.8 billion enterprise.
The Perelman School of Medicine has been ranked among the top medical schools in the United States for more than 20 years, according to U.S. News & World Report’s survey of research-oriented medical schools. The School is consistently among the nation’s top recipients of funding from the National Institutes of Health, with $405 million awarded in the 2017 fiscal year.
The University of Pennsylvania Health System’s patient care facilities include: The Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center — which are recognized as one of the nation’s top “Honor Roll” hospitals by U.S. News & World Report — Chester County Hospital; Lancaster General Health; Penn Medicine Princeton Health; Penn Wissahickon Hospice; and Pennsylvania Hospital – the nation’s first hospital, founded in 1751. Additional affiliated inpatient care facilities and services throughout the Philadelphia region include Good Shepherd Penn Partners, a partnership between Good Shepherd Rehabilitation Network and Penn Medicine, and Princeton House Behavioral Health, a leading provider of highly skilled and compassionate behavioral healthcare.
Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2017, Penn Medicine provided $500 million to benefit our community.