PET Identifies Inflammation in Fibromyalgia Patients

Positron emission tomography (PET) can highlight areas of increased glial activation in the brain of patients with fibromyalgia (FM), claims a new study.

Researchers at Massachusetts General Hospital (MGH; Boston, USA) and the Karolinska Institutet (KI; Solna, Sweden) conducted a PET study using a tracer that binds to the translocator protein (TSPO), which is upregulated in activated microglia and astrocytes. The study included 31 FM patients and 27 healthy controls examined using PET. Standardized uptake values were normalized by occipital cortex signal (SUVR) and distribution volume (VT), as computed from the tracer data. PET imaging metrics were compared across groups, and when differing across groups, against clinical variables.

The results revealed that FM patients demonstrated widespread cortical elevations, and no decreases, which was most pronounced in the medial and lateral walls of the frontal and parietal lobes. The elevations in the tracer and SUVR were correlated both spatially, and, in several areas, also in terms of magnitude. In addition, higher subjective ratings of fatigue in FM patients were associated with higher tracer SUVR in the anterior and posterior middle cingulate cortices. The study was published on September 14, 2018, in Brain, Behavior and Immunity.

“We don’t have good treatment options for fibromyalgia, so identifying a potential treatment target could lead to the development of innovative, more effective therapies,” said senior author Marco Loggia, PhD, of the MGH Martinos Center for Biomedical Imaging. “Finding objective neurochemical changes in the brains of patients with fibromyalgia should help reduce the persistent stigma that many patients face, often being told their symptoms are imaginary and there’s nothing really wrong with them.”

Fibromyalgia is characterized by such symptoms as chronic widespread pain, sleep problems, fatigue, and problems with thinking and memory; the cause is unknown. Fibromyalgia affects around seven times as many women as men, and typically develops between the ages of 30 and 50, but can occur in people of any age, including children and the elderly. Some estimates suggest nearly 1 in 20 people may be affected by fibromyalgia to some degree.

Related Links:
Massachusetts General Hospital
Karolinska Institutet