Ghrelin-reactive immunoglobulins and anxiety, depression and stress-induced cortisol response in adolescents. The TRAILS study
Background. Ghrelin, a hunger hormone, has been implicated in the regulation of stress-response, anxiety and depression. Ghrelin-reactive immunoglobulins (Ig) were recently identified in healthy and obese humans showing abilities to increase ghrelin's stability and orexigenic effects. Here we studied if ghrelin-reactive Ig are associated with anxiety and depression and with the stress-induced cortisol response in a general population of adolescents. Furthermore, to test the possible infectious origin of ghrelin-reactive Ig, their levels were compared with serum IgG against common viruses. Methods. We measured ghrelin-reactive IgM, IgG and IgA in serum samples of 1199 adolescents from the Dutch TRAILS study and tested their associations with 1) anxiety and depression symptoms assessed with the Youth Self-Report, 2) stress-induced salivary cortisol levels and 3) IgG against human herpesvirus 1, 2, 4 and 6 and Influenza A and B viruses. Results. Ghrelin-reactive IgM and IgG correlated positively with levels of antibodies against Influenza A virus. Ghrelin-reactive IgM correlated negatively with antibodies against Influenza B virus. Ghrelin-reactive IgM correlated positively with anxiety scores in girls and ghrelin-reactive IgG correlated with stress-induced cortisol secretion, but these associations were weak and not significant after correction for multiple testing. Conclusion. These data indicate that production of ghrelin-reactive autoantibodies could be influenced by viral infections. Serum levels of ghrelin-reactive autoantibodies probably do not play a role in regulating anxiety, depression and the stress-response in adolescents from the general population.
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*contributed equally to this study