PET points to neuroinflammation in chronic fatigue syndrome

The symptoms experienced by those who suffer from chronic fatigue may be related to acute inflammation in the brain, according to a PET study published March 24 in the Journal of Nuclear Medicine.

Yasuhito Nakatomi, MD, from the department of metabolism, endocrinology and molecular medicine at Osaka City University Graduate School of Medicine in Osaka, Japan, and colleagues wanted to confirm suspected neuroinflammation in the pathophysiology of patients with chronic fatigue/myalgic encephalomyelitis (CFS/ME). They evaluated a small group of subjects with the disorder with a biomarker targeting activated migroglia or astrocytes, a hallmark of neuroinflammation. The imaging agent used in this study is able to capture activated microglia or astrocytes by narrowing in on a translocator protein expressed when these are activated.

For this study, the researchers administered the targeted C-11 (R)-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carbox-amide (C-11 (R)-PK11195) in a total of 19 subjects, nine of whom were diagnosed with CFS/ME. Results of the study showed anywhere from 45 percent to a staggering 199 percent higher uptake of C-11 (R)-PK11195 in patients with CFS/ME compared to healthy controls.

“Neuroinflammation is present in widespread brain areas in CFS/ME patients and was associated with the severity of neuropsychologic symptoms,” wrote the authors. “Evaluation of neuroinflammation in CFS/ME patients maybe essential for understanding the core pathophysiology and for developing objective diagnostic criteria and effective medical treatments.”

Participants were asked to fill out a questionnaire on levels of fatigue, sensation, pain, depression and cognitive impairment. Areas of the brain that showed significantly more tracer uptake included the cingulate cortex, hippocampus, amygdala, thalamus, midbrain and pons. Uptake in the amygdala, thalamus and midbrain were linked to reports of cognitive impairment and pain score was associated with uptake in the cingulate cortex and thalamus, whereas depression score was correlated with uptake in the hippocampus.