title: Vagal stimulation modulates inflammation through a ghrelin mediated mechanism in traumatic brain injury.
abstract: Traumatic brain injury (TBI) releases a cascade of inflammatory cytokines. Vagal nerve stimulation (VNS) and ghrelin have known anti-inflammatory effects; furthermore, ghrelin release is stimulated by acetylcholine. We hypothesized VNS decreases post-TBI inflammation through a ghrelin-mediated mechanism. TBI was created in five groups of mice: sham, TBI, TBI/ghrelin, TBI/VNS, and TBI/VNS/ghrelin receptor antagonist (GRa). Serum and tissue ghrelin, and serum TNF-α were measured. Ghrelin increased following VNS 2 h post-TBI compared to sham or TBI. At 6 h, TBI and TBI/VNS/GRa had increased TNF-α compared to sham while TBI/VNS and TBI/ghrelin had TNF-α level comparable to sham. The highest ghrelin was measured in stomach where TBI decreased ghrelin in contrast to an increase by VNS. In conclusion, VNS increased serum ghrelin and decreased TNF-α following TBI. This was abrogated with GRa. Our data suggests that ghrelin plays an important role in the anti-inflammatory effects of VNS following TBI.
authors.affiliation: Department of Surgery, Division of Trauma, Surgical Critical Care and Burns, University of California San Diego, 200 W. Arbor Drive #8896, San Diego, CA 92103, USA. v3bansal@ucsd.edu
authors.forename: Vishal
authors.initials: V
authors.lastname: Bansal
authors.forename: Seok Yong
authors.initials: SY
authors.lastname: Ryu
authors.forename: Nicole
authors.initials: N
authors.lastname: Lopez
authors.forename: Sarah
authors.initials: S
authors.lastname: Allexan
authors.forename: Michael
authors.initials: M
authors.lastname: Krzyzaniak
authors.forename: Brian
authors.initials: B
authors.lastname: Eliceiri
authors.forename: Andrew
authors.initials: A
authors.lastname: Baird
authors.forename: Raul
authors.initials: R
authors.lastname: Coimbra
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001930:Brain Injuries / Q000378:metabolism*; D004195:Disease Models, Animal; D054439:Ghrelin / Q000097:blood / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism / Q000628:therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D054440:Receptors, Ghrelin / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D055536:Vagus Nerve Stimulation
chemical_list: D054439:Ghrelin; D054440:Receptors, Ghrelin; D014409:Tumor Necrosis Factor-alpha; D000109:Acetylcholine