Metabolism of the antioxidant micronutrient ergothioneine as a plasma biomarker of cognitive resilience in older people with Alzheimer's disease amyloid pathology.

BACKGROUND

Associations between dietary micronutrients and cognitive resilience to Alzheimer's disease (AD) amyloid pathology is currently unknown. We investigated whether plasma levels of L-ergothioneine (ET), its metabolite L-hercynine (HC), and their ratio (HC:ET, as an index of ET metabolism) affect known associations between biomarkers of amyloid pathology (p-Tau181 or p-Tau217) and cognitive decline.

METHODS

259 initially dementia-free participants recruited from memory clinics and the community in Singapore had baseline measurements of plasma p-Tau, ET, HC, as well as annual neuropsychological assessments for up to 5 years to derive cognitive trajectories based on Clinical Dementia Rating-Sum of Boxes (CDR-SB) slopes.

RESULTS

High HC:ET attenuated the positive correlations between plasma p-Tau and CDR-SB slopes. Compared with participants with low amyloid burden, participants with high amyloid burden had higher risk of cognitive decline when HC:ET was low (Hazard ratio [HR] = 2.33, p = 0.002), but not when HC:ET was high (HR = 1.47, p = 0.32).

CONCLUSION

The identification of ET metabolism as a novel biomarker of cognitive resilience supports further investigations into mechanisms underlying its neuroprotectant properties. ET should be further assessed as a potential candidate for countering amyloid pathology-associated cognitive decline.