Active brown adipose tissue protects against 'pre-prediabetes'

Date:
May 5, 2022
Source:
Society of Nuclear Medicine and Molecular Imaging
Summary:
In a prospective study of young, lean adults, PET/CT imaging
revealed that higher levels of active brown adipose tissue (also
known as 'brown fat') are more prevalent in individuals who exhibit
very early indications of metabolic disorders. The study suggests
that active brown fat is recruited to counteract 'pre-prediabetic'
states, potentially serving as a first-line protective mechanism
against very early metabolic or hormonal abnormalities.



FULL STORY ==========================================================================
In a prospective study of young, lean adults, PET/CT imaging revealed
that higher levels of active brown adipose tissue (also known as
"brown fat") are more prevalent in individuals who exhibit very early indications of metabolic disorders. Published ahead of print in The
Journal of Nuclear Medicine, the study suggests that active brown fat is recruited to counteract "pre- prediabetic" states, potentially serving
as a first-line protective mechanism against very early metabolic or
hormonal abnormalities.


========================================================================== Brown fat is a type of fat that is activated when a person gets cold,
producing heat to warm the body. The presence of brown fat was initially recognized on oncologic FDG PET/CT scans, which are now the most commonly
used technique for the in vivo detection of brown fat. Studies using PET
with FDG and/or other fatty-acid tracers have demonstrated that brown
fat consumes glucose and fatty acids, making it a potential target for
the treatment of obesity and other metabolic disorders.

"The primary aim of this study was to assess if there are differences in baseline glucose, insulin, lipid, and other metabolite levels between
subjects with varying amounts of brown fat. We also examined patient
blood samples and lifestyles to assess their association with brown fat levels," noted John P.

Crandall, BS, clinical research coordinator at the Mallinckrodt Institute
of Radiology at Washington University School of Medicine in St. Louis, Missouri.

Thirty-four healthy adult volunteers between the ages of 18 and 35
and with a body mass index (BMI) between 18 and 25 were enrolled in
the study. Blood samples were taken, and lifestyle interviews were
performed. To activate the brown fat, participants wore cooling suits to
bring their body's temperature to just above the shivering point. After
two hours, subjects removed the cooling suits and were imaging with FDG
PET/CT. Post-cooling blood samples were also taken after removal of the
cooling suits.

Activated brown fat was analyzed for each subject, and glucose, insulin,
lipid and other metabolite levels were correlated with volume and
intensity of the active brown fat. Using a median cut-off, participants
were classified as having high brown fat levels or low brown fat levels.

A higher level of activated brown fat was associated with early metabolic dysfunction. Pre-cooling glucose, insulin, thyroid stimulating hormone and triglyceride levels were significantly higher in the high brown fat group
than the low brown fat group. In addition, a significant difference in
BMI was found, with subjects with high brown fat levels having a higher
BMI than subjects with low levels of brown fat. Those with low brown
fat levels were more likely to report observing a controlled diet and exercising regularly.

"Our study suggests brown adipose tissue may considerably influence (and
be influenced by) overall metabolic health. Molecular imaging with FDG
remains the most useful non-invasive method for studying brown fat in
humans," said Richard L. Wahl, MD, FACR, director of the Mallinckrodt
Institute of Radiology and chair of the Department of Radiology at
Washington University School of Medicine. "Our findings show that
molecular imaging potentially may be useful for identifying patients who
are at risk of developing metabolic disorders and suggests activation of
brown fat is a metabolic coping mechanism in 'pre-pre- diabetes.' Further studies in larger populations are warranted to confirm and expand upon
our findings." This study was made available online in April 2022.


========================================================================== Story Source: Materials provided by Society_of_Nuclear_Medicine_and_Molecular_Imaging. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. John Crandall, Tyler J Fraum, Richard L. Wahl. Brown adipose
tissue: a
protective mechanism in "pre-prediabetes"? Journal of Nuclear
Medicine, 2022; jnumed.121.263357 DOI: 10.2967/jnumed.121.263357 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/05/220505114712.htm

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