Abstract
Background
Elevated blood neurofilament light chain (NFL) concentrations are indicative of neurodegeneration, while elevated kynurenine pathway (KP) metabolites are indicative of neuroinflammation. NFL and KP metabolites have independently been reported to be associated with neurodegenerative diseases, however the association between NFL and the KP metabolites have not been investigated previously. Therefore, the current study aimed to investigate whether an association between NFL and KP metabolites was present in elderly individuals to provide insight on the association between blood markers of neurodegeneration and neuroinflammation.
Methods
Plasma NFL concentrations were correlated with KP metabolites using Pearson's correlation coefficient in elderly individuals, aged 65–90 years, with normal global cognition (Mini Mental State Examination Score≥26) from the Kerr Anglican Retirement Village Initiative in Ageing Health cohort.
Results
A significant association between NFL and kynurenine to tryptophan ratio, reflecting 2,3-indoleamine dioxygenase activity was observed (K/T, r=.451, p<.0001). A positive correlation was also observed between NFL and kynurenine (r=.364, p<.0005), kynurenic acid (r=.384, p<.0001), 3-hydroxykynurenine (r=.246, p=.014), anthranilic acid (r=.311, p=.002) and quinolinic acid (r=.296, p=.003).
Conclusions
Observations from the current study suggest that an association between neurodegeneration and neuroinflammation manifests in the periphery.