A neuroimaging investigation into the role of peripheral metabolic biomarkers in the anticipation of reward in alcohol use

Abstract

Background: The relationship between alcohol use and metabolism has focused on the effects of alcohol use on metabolic factors. Metabolic factors, such as triglycerides, cholesterol, and glucose, have been shown to be associated with increased risk for heavy alcohol consumption and alcohol use disorder (AUD). It's been suggested that changes in metabolic factors may play a role in reward seeking behaviors and pathways. Studies on feeding behavior and obesity revealed the role of triglycerides in neural response to food cues in neurocircuitry regulating reward and feeding behaviors. This study aimed to explore the relationship of peripheral metabolism, alcohol use, and reward processing in individuals that use alcohol.

Methods: Ninety participants from a previously collected dataset were included in the analysis. Participants were treatment seeking, detoxified individuals with AUD and healthy individuals without AUD, with the following metabolic biomarkers: triglyceride, glucose, high- and low-density cholesterol, and HbA1c levels. Participants completed a neuroimaging version of the Monetary Incentive Delay task (MID).

Results: Correlations on peripheral metabolic biomarkers, alcohol use, and neural activity during reward anticipation and outcome during the MID task were not significant. Mediation models revealed triglycerides and high-density cholesterol had significant effects on left anterior insula during anticipation of potential monetary loss and this effect was not mediated by alcohol use.

Conclusion: Limbic recruitment by anticipation of monetary rewards revealed an independent relationship with peripheral metabolism and was not affected by individual differences in alcohol use, despite the effects of alcohol use on metabolic markers and reward processing neural circuitry.

Keywords: Alcohol use disorder; Peripheral metabolism; Resting State; Triglycerides; fMRI.

Figure 1.. Mediation model of the Relationship between Metabolism, Alcohol Use and Reward Anticipation.

Mediation models evaluated the total, controlled and nature direct, and natural indirect effects of each of the metabolic biomarkers on neural activation in each ROI during reward anticipation and outcome conditions of the MID task. Alcohol use was investigated as a mediator of these relationships. All mediations were controlled for age, race, gender, education, BMI, impulsivity, alcohol craving, and smoking status.