title: Muscle Sympathetic Nerve Activity Is Associated with Liver Insulin Sensitivity in Obese Non-Diabetic Men.
abstract: Introduction:Muscle sympathetic nerve activity (MSNA) may play a role in insulin resistance in obesity. However, the direction and nature of the relationship between MSNA and insulin resistance in obesity remain unclear. We hypothesized that resting MSNA would correlate inversely with both muscle and liver insulin sensitivity and that it would be higher in insulin-resistant vs. insulin-sensitive subjects.Materials and methods:Forty-five non-diabetic obese subjects were studied. As no significant relationships were found in women, the data presented in on 22 men aged 48 ± 12 years. Two-step (15 and 80 mU/m2/min) hyperinsulinaemic-euglycaemic clamps were performed using deuterated glucose to determine liver and muscle insulin sensitivity. Clinical and metabolic parameters were assessed. MSNA was measured via a microelectrode inserted percutaneously into the common peroneal nerve.Results:MSNA burst frequency correlated inversely with liver insulin sensitivity (r= -0.53,P= 0.02) and positively with the hepatokines C-reactive protein (CRP) and fibroblast growth factor (FGF)-19 (r= 0.57,P= 0.006, andr= -0.47,P= 0.03, respectively). MSNA burst frequency was lower in Liversencompared to Liverres(27 ± 5 vs. 38 ± 2 bursts per minute;P= 0.03). Muscle insulin sensitivity was unrelated to MSNA.Discussion:Sympathetic neural activation is related to liver insulin sensitivity and circulating hepatokines CRP and FGF-19 in non-diabetic obese men. These results suggest a potential hepato-endocrine-autonomic axis. Future studies are needed to clarify the influence of MSNA on liver insulin sensitivity in men.
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical Research Sydney, NSW, Australia.
authors.forename: Daniel L T
authors.initials: DL
authors.lastname: Chen
authors.affiliation: School of Medicine, University of Western SydneySydney, NSW, Australia; Neuroscience Research AustraliaSydney, NSW, Australia.
authors.forename: Rachael
authors.initials: R
authors.lastname: Brown
authors.affiliation: Philips Healthcare Luebeckertordamm, Hamburg, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Liess
authors.affiliation: Bioanalytical Mass Spectrometry Facility, UNSW SydneySydney, NSW, Australia; School of Medical Sciences, UNSW SydneySydney, NSW, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Poljak
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, University of Hong Kong Hong Kong, Hong Kong.
authors.forename: Aimin
authors.initials: A
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, University of Hong Kong Hong Kong, Hong Kong.
authors.forename: Jialiang
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Movelab, Newcastle University Newcastle, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Trenell
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical ResearchSydney, NSW, Australia; School of Health Science, University of WollongongWollongong, NSW, Australia.
authors.forename: Arthur
authors.initials: A
authors.lastname: Jenkins
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical Research Sydney, NSW, Australia.
authors.forename: Donald
authors.initials: D
authors.lastname: Chisholm
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical ResearchSydney, NSW, Australia; School of Medical Sciences, UNSW SydneySydney, NSW, Australia.
authors.forename: Dorit
authors.initials: D
authors.lastname: Samocha-Bonet
authors.affiliation: School of Medicine, University of Western SydneySydney, NSW, Australia; Neuroscience Research AustraliaSydney, NSW, Australia.
authors.forename: Vaughan G
authors.initials: VG
authors.lastname: Macefield
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical ResearchSydney, NSW, Australia; Department of Endocrinology and Diabetes Center, St. Vincent's HospitalSydney, NSW, Australia.
authors.forename: Jerry R
authors.initials: JR
authors.lastname: Greenfield
keywords: insulin resistance; liver insulin sensitivity; men; muscle sympathetic nervous activity; obesity