title: Pioglitazone does not affect vascular or inflammatory responses after endotoxemia in humans.
abstract: PPARgamma agonists have been proposed to exert more than metabolic benefits, particularly by anti-inflammatory mechanisms. We hypothesized that pioglitazone might modulate inflammatory and vascular responses to lipopolysaccharide (LPS). In a placebo-controlled parallel-group study in 18 healthy male subjects, the E. coli endotoxin model of inflammation (20 IU/kg i. v.) was employed to test the effect of 60 mg pioglitazone over nine days on inflammatory cytokines. Macrovascular function and microvascular blood flow were assessed by brachial artery ultrasound and retinal blood flow parameters, respectively. Pioglitazone increased brachial artery diameter by 5.6% but had no effect on other outcome parameters under resting conditions. LPS increased cytokine levels to peak concentrations of 91.3+/-22.5 ng/ml (IL-6), 261.4+/-60.0 ng/ml (TNFalpha), and 524.5+/-15.3 ng/ml (VCAM-1). The endotoxin caused microvascular vasodilation and increased retinal white blood cell flux, while baseline brachial artery diameter remained unchanged. Pioglitazone had no effect on inflammatory cytokine or adhesion molecule release but mitigated LPS-induced hypotension (p<0.05). Neither brachial artery function nor microvascular blood flow was altered by pioglitazone. In conclusion, acute immune reactions to LPS are not affected by pioglitazone, which exerts subtle vascular effects alone and during endotoxemia. The anti-inflammatory properties of short-term pioglitazone to endotoxins in healthy subjects are therefore limited.
authors.affiliation: Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Schaller
authors.forename: J
authors.initials: J
authors.lastname: Kolodjaschna
authors.forename: J
authors.initials: J
authors.lastname: Pleiner
authors.forename: F
authors.initials: F
authors.lastname: Mittermayer
authors.forename: S
authors.initials: S
authors.lastname: Kapiotis
authors.forename: L
authors.initials: L
authors.lastname: Schmetterer
authors.forename: M
authors.initials: M
authors.lastname: Wolzt
mesh_terms: D000328:Adult; D001916:Brachial Artery / Q000033:anatomy & histology / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects; D019446:Endotoxemia / Q000188:drug therapy* / Q000473:pathology*; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007113:Immunity, Innate / Q000187:drug effects; D007249:Inflammation / Q000473:pathology*; D015850:Interleukin-6 / Q000097:blood; D017078:Laser-Doppler Flowmetry; D008070:Lipopolysaccharides; D008297:Male; D000077205:Pioglitazone; D012171:Retinal Vessels / Q000187:drug effects; D045162:Thiazolidinediones / Q000627:therapeutic use*; D014303:Trinitrotoluene / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood; D014657:Vasculitis / Q000473:pathology*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D007004:Hypoglycemic Agents; D015850:Interleukin-6; D008070:Lipopolysaccharides; D045162:Thiazolidinediones; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D014665:Vasodilator Agents; D014303:Trinitrotoluene; D000077205:Pioglitazone