title: Obesity affects myocardial vasoreactivity and coronary flow response to insulin.
abstract: OBJECTIVE
  Obesity is associated with increased risk for cardiovascular diseases and peripheral endothelial dysfunction. We examined whether myocardial vasoreactivity and coronary-flow response to insulin stimulation are altered in obesity.
  
  
  METHODS
  Myocardial blood flow was quantitated in 10 obese men (body mass index, 33.6 +/- 1.9 kg/m(2)) and 10 healthy matched non-obese men (body mass index, 24.2 +/- 1.9 kg/m(2)), using positron emission tomography and oxygen-15-labeled water. The measurements were performed basally and during adenosine infusion (140 microg/kg per minute), with or without simultaneous physiological (1 mU/kg per minute) and supraphysiological (5 mU/kg per minute) hyperinsulinemia.
  
  
  RESULTS
  Basal myocardial blood flow was not significantly different between obese and non-obese subjects. Adenosine-stimulated flow was blunted in obese (3.2 +/- 0.6 mL/g per minute) when compared with non-obese subjects (4.0 +/- 1.1 mL/g per minute, p < 0.05). Simultaneous physiological hyperinsulinemia increased adenosine-stimulated myocardial flow significantly in both groups (to 4.03 +/- 1.24 and 4.85 +/- 1.04 mL/g per minute in obese and non-obese men, respectively; p < 0.05 vs. adenosine). Supraphysiological hyperinsulinemia further enhanced the adenosine-stimulated flow in non-obese subjects (to 5.56 +/- 0.98 mL/g per minute; p < 0.05) but not in obese subjects.
  
  
  CONCLUSIONS
  Young obese, healthy men have reduced myocardial vasoreactivity, which may represent an early precursor of future coronary artery disease. Additionally, insulin-induced enhancement of myocardial blood flow is blunted in obesity. Thus, endothelial dysfunction seems to also characterize myocardial vasculature of obese subjects.
authors.affiliation: Turku PET Centre, Department of Medicine, Turku University, Turku, Finland. jan.sundell@utu.fi
authors.forename: Jan
authors.initials: J
authors.lastname: Sundell
authors.forename: Hanna
authors.initials: H
authors.lastname: Laine
authors.forename: Matti
authors.initials: M
authors.lastname: Luotolahti
authors.forename: Kari
authors.initials: K
authors.lastname: Kalliokoski
authors.forename: Olli
authors.initials: O
authors.lastname: Raitakari
authors.forename: Pirjo
authors.initials: P
authors.lastname: Nuutila
authors.forename: Juhani
authors.initials: J
authors.lastname: Knuuti
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D000328:Adult; D001783:Blood Flow Velocity; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D001823:Body Composition; D015992:Body Mass Index; D003326:Coronary Circulation / Q000187:drug effects*; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate; D006801:Humans; D006946:Hyperinsulinism; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D010104:Oxygen Radioisotopes; D014055:Tomography, Emission-Computed; D014867:Water
chemical_list: D001786:Blood Glucose; D007328:Insulin; D010104:Oxygen Radioisotopes; D014867:Water; D000241:Adenosine