title: Free fatty acids normalize a rosiglitazone-induced visfatin release.
abstract: The detrimental effect of elevated free fatty acids (FFAs) on insulin sensitivity can be improved by thiazolidinediones (TZDs) in patients with type 2 diabetes mellitus. It is unknown whether this salutary action of TZD is associated with altered release of the insulin-mimetic adipocytokine visfatin. In this study, we investigated whether visfatin concentrations are altered by FFA and TZD treatment. In a randomized, double-blind, placebo-controlled, parallel-group study 16 healthy volunteers received an infusion of triglycerides/heparin to increase plasma FFA after 3 wk of treatment with rosiglitazone (8 mg/day, n = 8) or placebo (n = 8), and circulating plasma visfatin was measured. As a corollary, human adipocytes were incubated with synthetic fatty acids and rosiglitazone to assess visfatin release in vitro. The results were that rosiglitazone treatment increased systemic plasma visfatin concentrations from 0.6 +/- 0.1 to 1.7 +/- 0.2 ng/ml (P < 0.01). Lipid infusion caused a marked elevation of plasma FFA but had no effect on circulating visfatin in controls. In contrast, elevated visfatin concentrations in subjects receiving rosiglitazone were normalized by lipid infusion. In isolated adipocytes, visfatin was released into supernatant medium by acute addition and long-term treatment of rosiglitazone. This secretion was blocked by synthetic fatty acids and by inhibition of phosphatidylinositol 3-kinase or Akt. In conclusion, release of the insulin-mimetic visfatin may represent a major mechanism of metabolic TZD action. The presence of FFA antagonizes this action, which may have implications for visfatin bioactivity.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: Dominik G
authors.initials: DG
authors.lastname: Haider
authors.forename: Friedrich
authors.initials: F
authors.lastname: Mittermayer
authors.forename: Georg
authors.initials: G
authors.lastname: Schaller
authors.forename: Michaela
authors.initials: M
authors.lastname: Artwohl
authors.forename: Sabina M
authors.initials: SM
authors.lastname: Baumgartner-Parzer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Prager
authors.forename: Michael
authors.initials: M
authors.lastname: Roden
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000187:drug effects; D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage; D002478:Cells, Cultured; D016207:Cytokines / Q000097:blood*; D004347:Drug Interactions; D005230:Fatty Acids, Nonesterified / Q000008:administration & dosage* / Q000097:blood*; D006493:Heparin / Q000008:administration & dosage; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007333:Insulin Resistance; D008297:Male; D054409:Nicotinamide Phosphoribosyltransferase; D000077154:Rosiglitazone; D015398:Signal Transduction / Q000187:drug effects; D045162:Thiazolidinediones / Q000008:administration & dosage*; D014280:Triglycerides / Q000008:administration & dosage / Q000097:blood
chemical_list: D000925:Anticoagulants; D016207:Cytokines; D005230:Fatty Acids, Nonesterified; D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D014280:Triglycerides; D000077154:Rosiglitazone; D006493:Heparin; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human