Alcohol Clin Exp Res. 2021 Sep 15. doi: 10.1111/acer.14712. Online ahead of print.
ABSTRACT
BACKGROUND: Chronic alcohol consumption is associated with structural brain changes and increased inflammatory signaling throughout the brain and body. Increased inflammation in the brain has been associated with structural brain damage. Recent studies have also shown that neurofilament light polypeptide (NfL) is released into circulation following neuronal damage. NfL has thus been proposed as a biomarker for neurodegenerative diseases but has not been explored in connection with alcohol use disorder. For this secondary data analysis, we proposed a conceptual model linking alcohol consumption, the pro-inflammatory cytokine IL-6, brain structure and NfL in heavy-drinking participants.
METHODS: Of the 182 individuals enrolled in this study, 81 participants had useable gray matter (GM) data and 80 had useable white matter (WM) data. A subset of these had NfL (n = 78) and IL-6 (n = 117) data. GM thickness was extracted from middle frontal brain regions using Freesurfer. Mean WM diffusivity values were extracted from Tract Based Spatial Statistics. NfL and IL-6 were measured from blood. Regression models were used to test individual linkages in the conceptual model. Based on significant regression results, we created a simplified conceptual model which was tested using path analysis.
RESULTS: In regressions, negative relationships emerged between GM and both drinks per drinking day (DPDD) (p = .018) and NfL (p = .004). A positive relationship emerged between WM diffusivity and DPDD (p =.033). IL-6 was not significantly associated with alcohol use, GM or WM. The final path model demonstrated adequate fit to the data and showed significant, negative associations between DPDD and middle frontal gyrus (MFG) Thickness and between MFG Thickness and NfL, but a non-significant association between DPDD and NfL.
CONCLUSIONS: Data suggest that drinking is associated with lower GM thickness and higher WM diffusivity and that lower GM thickness is associated with higher circulating NfL. This is the first study to demonstrate an association between brain structure and NfL in a sample of heavy drinkers.
PMID:34523725 | DOI:10.1111/acer.14712
