Liraglutide Reduces CNS Activation in Response to Visual Food Cues Only After Short-term Treatment in Patients With Type 2 Diabetes

OBJECTIVE: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are associated with reduced appetite and body weight. We investigated whether these effects could be mediated by the central nervous system (CNS).

RESEARCH DESIGN AND METHODS: We performed a randomized crossover study in obese patients with type 2 diabetes (n = 20, mean age 59.3 ± 4.1 years, mean BMI 32 ± 4.7 kg/m(2)), consisting of two periods of 12-week treatment with either liraglutide 1.8 mg or insulin glargine. Using functional MRI, we determined the effects of treatment on CNS responses to viewing food pictures in the fasted condition and 30 min after meal intake.

RESULTS: After 12 weeks, the decrease in HbA1c was larger with liraglutide versus insulin glargine (Δ-0.7% vs. -0.2%, P < 0.001). Body weight decreased during liraglutide versus insulin glargine (Δ-3.3 kg vs. 0.8 kg, P < 0.001). After 10 days, patients treated with liraglutide, compared with insulin glargine, showed decreased responses to food pictures in insula and putamen (P ≤ 0.02). In addition, liraglutide enhanced the satiating effect of meal intake on responses in putamen and amygdala (P ≤ 0.05). Differences between liraglutide and insulin glargine were not observed after 12 weeks.

CONCLUSIONS: Compared with insulin, liraglutide decreased CNS activation significantly only after short-term treatment, suggesting that these effects of GLP-1RA on the CNS may contribute to the induction of weight loss, but not necessarily to its maintenance, in view of the absence of an effect of liraglutide on CNS activation in response to food pictures after longer-term treatment.