• Marie François, Swapnali Barde, Romain Legrand, Nicolas Lucas, Saida Azhar, Mohammed El Dhaybi, Charlène Guerin, Tomas Hökfelt, Pierre Déchelotte, Moise Coëffier, and Sergueï O Fetissov.
• Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen, France.
• Nutrition. 2016 Jun 1; 32 (6): 709-15.

ObjectivesMechanisms of high-fat diet (HFD)-induced obesity may involve ghrelin, an orexigenic and adipogenic hormone secreted by the stomach. Previous studies showed that obese subjects may display higher numbers of ghrelin-producing cells and increased affinity of plasma immunoglobulins (Ig) for ghrelin, protecting it from degradation. The aim of this study was to determine if a HFD in mice would increase the number of ghrelin-expressing cells and affinity of ghrelin-reactive IgG.MethodsObesity in mice was induced by consumption of a 13-wk HFD. The number of preproghrelin mRNA-expressing cells in the stomach was analyzed by in situ hybridization and compared with chow-fed, nonobese controls and with genetically obese ob/ob mice. Affinity of ghrelin-reactive IgG was analyzed using surface plasmon resonance. Plasma levels of ghrelin and des-acyl ghrelin were measured.ResultsHFD resulted in 30% of body fat content versus only 8% in controls (P < 0.001). The number of preproghrelin mRNA-producing cells was 15% (P < 0.05) higher in HFD-fed mice than in controls, contrasting with ob/ob mice, having a 41% (P < 0.001) decrease. Both models of obesity had normal plasma levels of ghrelin but a decrease of its des-acylated form. Ghrelin-reactive IgG affinity was found in the micromolar range with mean values of the dissociation equilibrium constant 1.5-fold (P < 0.05) lower in HFD-fed versus control mice.ConclusionResults from the present study showed that HFD in mice induces obesogenic changes, including increased numbers of ghrelin precursor-expressing cells and increased affinity of ghrelin-reactive IgG. Such changes may contribute to the mechanisms of HFD-induced obesity.Copyright © 2016 Elsevier Inc. All rights reserved.

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