title: Plasma interleukin-6 levels are independently associated with insulin secretion in a cohort of Italian-Caucasian nondiabetic subjects.
abstract: We have investigated the relationships between plasma interleukin-6 (IL-6) levels and insulin sensitivity and insulin secretion in a cohort of Italian-Caucasian glucose-tolerant subjects. Insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp, and first-phase insulin secretion was measured by intravenous glucose tolerance test. Fasting plasma IL-6 concentration was negatively correlated with the rate of insulin-stimulated glucose disposal (M) (P = 0.001). The correlation remained statistically significant, while attenuated, after adjusting for sex, age, and BMI (P < 0.03); after an additional adjustment for free fatty acids (FFAs), a further attenuation was observed, but statistical significance was maintained (P < 0.044). Fasting plasma IL-6 concentration was positively correlated with first-phase insulin secretion assessed as acute insulin response (AIR) (P = 0.001). The correlation remained significant after adjusting for sex, age, and BMI (P = 0.003). To estimate the independent contribution of plasma IL-6 levels to AIR, we carried out forward stepwise linear regression analysis in a model that included sex, age, BMI, waist-to-hip ratio, FFAs, and insulin-stimulated glucose disposal. Only insulin sensitivity and plasma IL-6 concentration were independently associated with AIR, accounting, respectively, for 19.0 and 5.2% of its variation. These data indicate that IL-6 is associated in a reciprocal manner with the two pathophysiological components of type 2 diabetes, i.e., insulin resistance and insulin secretion.
authors.affiliation: Dipartimento di Medicina Sperimentale e Clinica, Policlinico Mater Domini-Via Tommaso Campanella 88100, Catanzaro, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Andreozzi
authors.forename: Emanuela
authors.initials: E
authors.lastname: Laratta
authors.forename: Marina
authors.initials: M
authors.lastname: Cardellini
authors.forename: Maria A
authors.initials: MA
authors.lastname: Marini
authors.forename: Renato
authors.initials: R
authors.lastname: Lauro
authors.forename: Marta L
authors.initials: ML
authors.lastname: Hribal
authors.forename: Francesco
authors.initials: F
authors.lastname: Perticone
authors.forename: Giorgio
authors.initials: G
authors.lastname: Sesti
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D015331:Cohort Studies; D005215:Fasting; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D007333:Insulin Resistance; D000078790:Insulin Secretion; D015850:Interleukin-6 / Q000097:blood*; D007558:Italy; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D044465:White People
chemical_list: D001786:Blood Glucose; D007328:Insulin; D015850:Interleukin-6