New research in the FASEB Journal uncovers
metabolic flexibility: 30 percent of cells that
appear to be white fat cells rapidly turn into brown
fat cells after cold stress.
The roles that white fat and brown fat play in
metabolism is well documented, but new research
published in the January 2015 issue of the FASEB
Journal presents a new wrinkle: each type of fat may
change into the other, depending on the temperature.
In particular, cold temperatures may encourage "unhealthy"
white fat to change into "healthy" brown fat.
"Fat cells can adopt a range of metabolic phenotypes,
depending on physiological conditions and location
in the body," said James G. Granneman, Ph.D., a
researcher involved in the work from the Center for
Integrative Metabolic and Endocrine Research at the
Wayne State University School of Medicine in
Detroit, MI. "Our long-term goal is to harness this
cellular and metabolic flexibility for the treatment
of metabolic disorders linked to dysfunctional fat,
such as type 2 diabetes."
Scientists used techniques that allowed them to tag
specific cell populations (undifferentiated
progenitors or differentiated adipocytes) in mice
before exposure to cold. Mice were then exposed to
mild cold stress, and researchers traced whether
these cells became brown adipocytes in various
adipose tissues in the body.
Results suggested that in classic brown adipose
tissue, tagged progenitors divide and become new
brown adipocytes. This process required neural
activation of the tissue and was mediated by a
specific receptor subtype.
In contrast, the vast majority of brown adipocytes
that appear in white adipose tissue were tagged
previously with a marker of mature fat cells.
The study indicated that about 30 percent of cells
that appear to be white adipocytes before cold
stress can rapidly turn on the brown adipocyte
program following cold stress.
"If you want to rev up your metabolism, don't throw
out your winter coat just yet," said Gerald
Weissmann, M.D., Editor-in-Chief of the FASEB
Journal. "We still need know if this holds true in
humans. What's more, the important part of this
research is that one type of fat can change to
another, and that cold triggers cellular mechanisms
that lead to the formation of more brown fat. The 'switch'
that controls what type of fat is created may be a
promising drug target for a variety of
Cool Temperature Alters Human Fat and Metabolism
Newly isolated 'beige fat' cells could help fight
For more information
Details: Yun-Hee Lee, Anelia P. Petkova, Anish A.
Konkar, and James G. Granneman
Cellular origins of cold-induced brown adipocytes in
FASEB J. January 2015 29:286-299;