Circulating Immune and Endocrine Markers in Currently Drinking and Abstinent Individuals With Alcohol Use Disorder and Controls

Alcohol use disorder (AUD) is associated with changes in endocrine and immune system function. This study is a secondary analysis aimed at investigating changes in circulating immune and endocrine biomarkers in blood samples from three groups: (1) healthy controls (HC, N = 12), (2) AUD-currently drinking, nontreatment seeking (CD, N = 9), and (3) AUD-abstinent, treatment-seeking (AB, N = 10; abstinent for at least 6 weeks). We hypothesized that both immune and endocrine biomarker concentrations would be different in AUD groups compared to healthy controls. Immune biomarkers included IL-8, IL-18, CCL2, TNF-α, IL-1RA, IL-6, and IL-10. Endocrine biomarkers included brain-derived neurotrophic factor (BDNF), glucagon-like peptide 1 (GLP-1), ghrelin, gastric inhibitory peptide (GIP), growth hormone, leptin, and insulin. Biomarker concentrations were compared between the three groups while controlling for age and sex, and associations between biomarker concentrations and behavioral measures were explored. IL-8 concentrations were elevated in AB compared to CD and HC (F(2,29) = 6.33, p = 0.006, ƞ_p ² = 0.318). BDNF concentrations were lower in AB compared to HC (F(2,30) = 4.34, p = 0.02, ƞ_p ² = 0.266). GLP-1 concentrations were higher in AB compared to HC (F(2,25) = 4.22, p = 0.03, ƞ_p ² = 0.287). Exploratory analyses in combined groups showed that measures of past drinking, AUD severity, and anxiety/depression positively correlated with IL-18 and TNF-α and negatively correlated with BDNF. These results demonstrate that circulating concentrations of both immune and endocrine proteins are altered in abstinent individuals with a history of severe AUD (AB group) compared to healthy controls. In contrast, no group differences were observed for any biomarker between the nontreatment seeking, currently drinking people with AUD and the HC group. Our findings highlight the importance of accounting for AUD severity, comorbidities, and treatment-seeking status, especially when studying alcohol-related biomarkers.