Association of metabolic parameters and rs726344 in FNDC5 with serum irisin concentrations

• Published in: International Journal of Obesity 2016-02, Vol.40 (2), p.260-265
• Main Authors: Ebert, T, Kralisch, S, Wurst, U, Scholz, M, Stumvoll, M, Kovacs, P, Fasshauer, M, Tönjes, A
• Format: Article
• Language: English
• Subjects: 13/21; 38/23; 631/208/2489; 631/443/163; 631/443/319/1642/2037; 631/45/127; 692/308/174; 692/499; 692/699/317; Adipocytes; Adult; Analysis; Blood Glucose - metabolism; Body fat; Body Fat Distribution; Care and treatment; Diabetes; Diabetes mellitus; Diabetes mellitus (non-insulin dependent); Dyslipidemia; Endocrinology; Enzyme-Linked Immunosorbent Assay; Epidemiology; Fasting; Female; Fibronectin; Fibronectins; Fibronectins - blood; Fibronectins - genetics; Gene Expression Regulation - genetics; Gene Frequency; Genetic diversity; Genetic Predisposition to Disease - epidemiology; Germany - epidemiology; Glucose; Glucose metabolism; Glucose tolerance; Glucose tolerance test; Health Promotion and Disease Prevention; Humans; Insulin; Insulin resistance; Insulin Resistance - genetics; Internal Medicine; Investigations; Lipid metabolism; Lipids; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolic disorders; Metabolic syndrome; Metabolic Syndrome - blood; Metabolic Syndrome - epidemiology; Metabolic Syndrome - genetics; Metabolism; Middle Aged; Nephrology; Obesity; original-article; Parameters; Phenotypes; Physiological aspects; Proteins; Public Health; Regression analysis; Regression models; Renal function; Reproducibility of Results; Risk factors; Serum levels; Type 2 diabetes
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/ijo.2015.157

Background/Objectives: Irisin has been suggested as a novel myokine with beneficial effects in rodents. However, previous data in humans showed conflicting results regarding its association with metabolic phenotypes and regulation of secretion. Furthermore, although an association of rs726344 in FNDC5 (fibronectin type III domain containing 5) coding for irisin with insulin sensitivity was reported, the effects of genetic variation at this locus on irisin serum levels have not been investigated, so far. Therefore, we investigated circulating irisin and the associations with rs726344 in a cohort of >1000 subjects. Subjects/Methods: Irisin serum concentrations were measured with enzyme-linked immunosorbent assay. Associations with metabolic parameters including renal function, glucose and lipid metabolism, inflammation, as well as adipokine profiles, were assessed in regression models. Dynamic changes of serum irisin were investigated during oral glucose tolerance test (OGTT) in a subset of the cohort ( n =136). rs726344 was genotyped in all subjects and analyzed for associations with serum irisin and traits of the metabolic syndrome. Results: Irisin was negatively associated with fat mass, fasting glucose and dyslipidemia but not with other adipokines. Moreover, irisin decreased during an OGTT in a subcohort comprising subjects with normal glucose tolerance, impaired fasting glucose, impaired glucose tolerance and type 2 diabetes mellitus. rs726344 was not associated with serum irisin levels or with other anthropometric and biochemical parameters. Conclusions: Circulating irisin levels are associated with a beneficial metabolic profile but not with other adipokines and not with rs726344 in our cohort. Our data suggest a potential favorable role of irisin in the regulation of metabolism.