Glucose intolerance induces anxiety-like behaviors independent of obesity and insulin resistance in a novel model of nutritional metabolic stress
Type 2 diabetes (T2D) and its comorbidities are a major public health concern. In addition to peripheral tissues, T2D also impacts the central nervous system leading to neurocognitive impairments, including memory deficits, anxiety, and depression. The metabolic determinants of these neurocognitive impairments remain unidentified. Here, we used a novel proprietary high-fat diet, in which glucose intolerance precedes weight gain, to decipher the metabolic determinants of neurocognitive affects. We show that this model exhibits anxiety-like behaviors, without eliciting depression nor recognition memory deficits. Long-term feeding leads to weight gain, brain glucose hypometabolism and impaired recognition memory alongside the early onset anxiety-like behavior. Using an established genetic model of T2D (db/db) and of diet-induced obesity we show that additional insulin resistance and obesity are associated with depressive-like behaviors and recognition memory deficits. Our findings indicate that glucose intolerance alone can elicit anxiety-like behaviors. Through this study we also provide a novel nutritional model to characterize the discrete effects of glucose intolerance on cognition, behavior, and the physiology of metabolic disease.