Sex-related effects of nutritional supplementation of Escherichia coli: Relevance to eating disorders

Objectives: The biological background of sex-related differences in the development of eating disorders (EDs) is unknown. Recent data showed that gut bacteria Escherichia coli induce autoantibodies against anorexigenic alpha-melanocyte-stimulating hormone (alpha-MSH) associated with psychopathology in ED. The aim of this study was to compare the effects of E. coli on feeding and autoantibodies against alpha-MSH and adrenocorticotropic hormone (ACTH), between female and male rats. Methods: Commensal E. coli K12 were given in a culture medium daily to adult Wistar rats by intragastric gavage over a 3-wk period; control rats received culture medium only. Results: Before gavage, E. coli 1(12 DNA was detected in feces of female but not male rats. E. coli provision was accompanied by an increase in body weight gain in females, but a decrease in body weight gain and food intake in males. Independent of E. coli treatment, plasma levels of anti-alpha-MSH and ACTH immunoglobulin (Ig)G were higher in female than male rats. Females responded to E. coli by increasing alpha-MSH IgG levels and affinity, but males by increasing alpha-MSH IgM levels. Affinity of IgG for ACTH was increased in both E. coli-treated females and males, although with different kinetics. IgG from females stimulated more efficiently alpha-MSH-induced cyclic adenosine monophosphate production by melanocortin 4 receptor-expressing cells compared with IgG from males. Discussion: Sex-related response to how E. coli affects feeding and anti-melanocortin hormone antibody production may depend on the presence of these bacteria in the gut before E. coli supplementation. These data suggest that sex-related presence of certain gut bacteria may represent a risk factor for ED development. (C) 2015 Elsevier Inc. All rights reserved.