title: Immunization against active ghrelin using virus-like particles for obesity treatment.
abstract: Ghrelin is a gut hormone that stimulates food intake. In physiological conditions, ghrelin plasma levels rise with fasting and decrease after meals. Obese individuals have low fasting ghrelin levels that rise after food restriction, which is pointed out as a reason for the difficulty in maintaining weight loss. Some bariatric surgery procedures prevent rise in ghrelin levels with weight loss and this has been hypothesised to contribute to the long-term success of the treatment. The main goal of this study was to develop a safe and effective anti-ghrelin vaccine for obesity, through the chemical conjugation of ghrelin with a virus like particle, namely NS1 protein tubules from the Bluetongue Virus (BTV) using a hetero-bifunctional cross linker. Male adult C57BL/6 mice, with a normal weight and with diet-induced obesity (DIO), were randomized into six weight matched groups (n=6/group) and each group of mice received three intra-peritoneal injections with two weeks intervals, containing either 75 μg of ghrelin- NS1 immunoconjugate, 75 μg of NS1 or PBS. Our data show that immunized animals present increasing titres of anti-ghrelin antibodies, while their cumulative food intake significantly decreased and energy expenditure was significantly enhanced, although there were no significative changes in body weight.Vaccinated DIO mice also displayed significant decrease of NPY gene expression in the basal hypothalamus reflecting a decrease in central orexigenic signals. This study suggests that this anti-ghrelin vaccine has a positive impact on energy homeostasis and may be an additional therapeutical tool to be used with diet and exercise for obesity treatment.
authors.affiliation: Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal. mpmonteiro@icbas.up.pt.
authors.forename: Sara
authors.initials: S
authors.lastname: Andrade
authors.forename: Filipa
authors.initials: F
authors.lastname: Pinho
authors.forename: Andreia M
authors.initials: AM
authors.lastname: Ribeiro
authors.forename: Marcos
authors.initials: M
authors.lastname: Carreira
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Casanueva
authors.forename: Polly
authors.initials: P
authors.lastname: Roy
authors.forename: Mariana P
authors.initials: MP
authors.lastname: Monteiro
mesh_terms: D000818:Animals; D001835:Body Weight; D004435:Eating; D004734:Energy Metabolism; D054439:Ghrelin / Q000008:administration & dosage*; D006728:Hormones / Q000097:blood; D007114:Immunization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000097:blood / Q000235:genetics / Q000628:therapy*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D058425:Vaccines, Virus-Like Particle / Q000627:therapeutic use*; D017361:Viral Nonstructural Proteins / Q000502:physiology*
chemical_list: D054439:Ghrelin; D006728:Hormones; C078966:NS1 protein, bluetongue virus; D012333:RNA, Messenger; D058425:Vaccines, Virus-Like Particle; D017361:Viral Nonstructural Proteins