Date: April 4, 2014
Toward a clearer diagnosis of chronic fatigue syndrome
Researchers at the RIKEN Center for Life Science Technologies, in
collaboration with Osaka City University and Kansai University of
Welfare Sciences, have used functional PET imaging to show that levels
of neuroinflammation, or inflammation of the nervous system, are
higher in patients with chronic fatigue syndrome than in healthy people.
Chronic fatigue syndrome, which is also known as myalgic
encephalomyelitis, is a debilitating condition characterized by
chronic, profound, and disabling fatigue. Unfortunately, the causes
are not well understood.
Neuroinflammation - the inflammation of nerve cells - has been
hypothesized to be a cause of the condition, but no clear evidence has
been put forth to support this idea. Now, in this clinically important
study, published in The Journal of Nuclear Medicine, the researchers
found that indeed the levels of neuroinflammation markers are elevated
in CFS/ME patients compared to the healthy controls.
The researchers performed PET scanning on nine people diagnosed with
CFS/ME and ten healthy people, and asked them to complete a
questionnaire describing their levels of fatigue, cognitive
impairment, pain, and depression. For the PET scan they used a protein
that is expressed by microglia and astrocyte cells, which are known to
be active in neuroinflammation.
The researchers found that neuroinflammation is higher in CFS/ME patients than in healthy people. They also found that inflammation in certain areas of the brain - the cingulate cortex, hippocampus, amygdala, thalamus, midbrain, and pons - was elevated in a way that correlated with the symptoms, so that for instance, patients who reported impaired cognition tended to demonstrate neuroinflammation in the amygdala, which is known to be involved in cognition. This provides clear evidence of the association between neuroinflammation and the symptoms experienced by patients with CFS/ME.
Though the study was a small one, confirmation of the concept that PET
scanning could be used as an objective test for CFS/ME could lead to
better diagnosis and ultimately to the development of new therapies to
provide relief to the many people around the world afflicted by this
Dr. Yasuyoshi Watanabe, who led the study at RIKEN, stated, 'We plan
to continue research following this exciting discovery in order to
develop objective tests for CFS/ME and ultimately ways to cure and
prevent this debilitating disease.'
Yasuhito Nakatomi, Kei Mizuno, Akira Ishii, Yasuhiro Wada, Masaaki
Tanaka, Shusaku Tazawa, Kayo Onoe, Sanae Fukuda, Joji Kawabe, Kazuhiro
Takahashi, Yosky Kataoka, Susumu Shiomi, Kouzi Yamaguti, Masaaki
Inaba, Hirohiko Kuratsune, Yasuyoshi Watanabe, 'Neuroinflammation in
patients with chronic fatigue syndrome/myalgic encephalomyelitis: a
11C-(R)-PK11195 positron emission tomography study', The Journal of
Nuclear Medicine, vol.55, No.6, 2014, DOI: 10.2967/jnumed.113.131045
Pathophysiological and Health Science Team
Imaging Application Group
Division of Bio-Function Dynamics Imaging
RIKEN Center for Life Science Technologies
RIKEN Global Relations and Research Coordination Office
Tel: +81-(0)48-462-1225 / Fax: +81-(0)48-463-3687
(c) 2014 Riken