Low APP levels linked to MS fatigue

A new study has found that multiple sclerosis (MS) patients with fatigue have lower levels of amyloid precursor protein (APP) in the cerebrospinal fluid compared with both MS patients without fatigue and healthy people.

APP is a molecule involved in nerve cell function. Cerebrospinal fluid is what bathes the brain and spinal cord.

MS fatigue affects around 80 per cent of people with MS and is the condition’s main cause of disability. But the current measurements for assessing fatigue are subjective questionnaires which cannot distinguish between different types. Researchers said there is therefore a need “for objective biomarkers of fatigue in MS.”

They analysed cerebrospinal fluid and clinical parameters from 31 people with MS who had a mean age of 38.6, along with 17 healthy people with a mean average age of 26.9.

Fatigue was assessed with the Fatigue Severity Scale (FSS) and insomnia, which is associated with fatigue, with the Insomnia Severity Index (ISI). Based on the FSS score, 19 MS patients were found to have fatigue, while 12 were not.

MS patients with both with fatigue and without it had higher levels of neurofilament light chain, which is a marker of neuronal damage, compared with healthy controls. But those with fatigue had much lower levels of APP than the non-fatigued and the healthy controls. “To the best of our knowledge, this study is the first to find lower APP levels in a patient group, and the first to investigate the relationship of APP and fatigue in any disease,” the researchers wrote.