The Impact of Vertical Sleeve Gastrectomy on Behavioral and Reward-Related Outcomes

Vertical sleeve gastrectomy (VSG) is widely recognized as an effective metabolic surgery for achieving durable weight loss and improving obesity-related comorbidities. However, some patients experience deteriorating mental health post-surgery, prompting investigation into underlying mechanisms.

This study examined diet-induced obese C57BL/6J male mice that underwent either VSG or sham surgery, as well as a cohort of high-fat diet-fed male mice subsequently transitioned to a low-fat diet (LFD), compared to chow-fed controls. We assessed metabolic parameters (body weight, food intake, glucose tolerance, and body composition), interscapular temperature, a proxy measure of thermogenic activity via transponder-monitored activity and temperature in brown and white adipose tissue and behavioral outcomes related to hedonic processing, anxiety-like behavior, motivation, and cognitive flexibility.

VSG produced rapid and sustained reductions in body weight, transient decreases in food intake, reduced adiposity, trends toward improved glucose regulation, and increased interscapular adipose tissue temperature, suggesting increased brown adipose tissue thermogenic activity. Preferences for sucrose and saccharin remained unchanged in the low-fat diet-fed cohort. VSG reduced responding to rewards under high-fat diet conditions, an effect not observed in a separate cohort of mice transitioned to a LFD post-surgery but did not significantly enhance cognitive flexibility. In contrast, sham-operated low-fat diet-fed mice demonstrated improved cognitive flexibility. Anxiety-like behaviors were unaffected by VSG.

These findings confirm the robust metabolic benefits of VSG. Exploratory comparisons between independent dietary cohorts suggest that dietary context may influence reward-related and cognitive outcomes following VSG. However, these findings are based on comparisons between separate dietary cohorts and should be interpreted cautiously. Further studies are required to determine whether dietary context contributes to long-term behavioral outcomes following VSG.