筋痛性脳脊髄炎／慢性疲労症候群の脳科学研究

Brain Science on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

筋痛性脳脊髄炎/慢性疲労症候群（ME/CFS）は，原因不明の激しい疲労・倦怠感とともに，労作後に増悪する極度の倦怠感，微熱，疼痛，脱力，認知機能障害，睡眠障害などの多彩な症状が長期にわたり継続し，日常生活や社会生活に支障をきたす疾患である。私たちは，この疾患に対し，血液因子や機能検査による客観的な疾患バイオマーカーを探索するとともに，PETやMRI，MEGなどを用いたイメージング研究により，ME/CFSの脳科学を推進してきた。

Abstract

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disease characterized by chronic, profound, disabling, and unexplained fatigue. A variety of studies have been performed to establish objective biomarkers of the disease, including positron emission tomography (PET) molecular imaging and neuro-functional imaging using magnetic resonance imaging (MRI) and magnetoencephalogram (MEG). In this chapter, we summarize the results from PET, MRI, and MEG imaging. Regional cerebral blood flow and glucose utilization rates are decreased in patients with ME/CFS as compared with age- and sex-matched healthy subjects. Acetyl-L-carnitine uptake into the releasable pool of glutamate and serotonin transporters densities are decreased in a few specific brain regions, mostly in the anterior cingulate in the patients. Although it is hypothesized that brain inflammation is involved in the pathophysiology of ME/CFS, there was no direct evidence of neuroinflammation in patients. Our recent PET study successfully demonstrated that neuroinflammation is present in widespread brain areas in ME/CFS patients, and is associated with the severity of neuropsychological symptoms. Evaluation of neuroinflammation in patients with ME/CFS may be essential for understanding the core pathophysiology, as well as for developing objective diagnostic criteria and effective medical treatments for ME/CFS. By using specific neurological features of these patients such as prefrontal cortical atrophies and the over-guarding phenomenon were found using MRI and functional MRI, respectively. We here describe related pathophysiological findings and topics in order to aid in the development of future therapies for ME/CFS patients.