title: Insulin improves myocardial blood flow in patients with type 2 diabetes and coronary artery disease.
abstract: Insulin infusion improves myocardial blood flow (MBF) in healthy subjects. Until now, the effect of insulin on myocardial perfusion in type 2 diabetic subjects with coronary artery disease (CAD) has been unknown. We studied the effects of insulin on MBF in ischemic regions evaluated by single-photon emission-computed tomography and coronary angiography and in nonischemic regions in 43 subjects (ages 63 +/- 7 years) with type 2 diabetes (HbA(1c) 7.1 +/- 0.9%). MBF was measured at fasting and during a euglycemic-hyperinsulinemic clamp at rest (n = 43) and during adenosine-induced (140 mug . kg(-1) . min(-1) for 7 min) hyperemia (n = 26) using positron emission tomography and (15)O-labeled water. MBF was significantly attenuated in ischemic regions as compared with in nonischemic regions (P < 0.0001) and was increased by insulin as compared with in the fasting state (P < 0.0001). At rest, insulin infusion increased MBF by 13% in ischemic regions (P = 0.043) and 22% in nonischemic regions (P = 0.003). During adenosine infusion, insulin enhanced MBF by 20% (P = 0.018) in ischemic regions and 18% (P = 0.045) in nonischemic regions. In conclusion, insulin infusion improved MBF similarly in ischemic and nonischemic regions in type 2 diabetic subjects with CAD. Consequently, in addition to its metabolic effects, insulin infusion may improve endothelial function and thus increase the threshold for ischemia and partly contribute to the beneficial effects found in clinical trials in these subjects.
authors.affiliation: Turku PET Centre, Turku University Hospital, Finland. rimala@utu.fi
authors.forename: Riikka
authors.initials: R
authors.lastname: Lautamäki
authors.forename: K E Juhani
authors.initials: KE
authors.lastname: Airaksinen
authors.forename: Marko
authors.initials: M
authors.lastname: Seppänen
authors.forename: Jyri
authors.initials: J
authors.lastname: Toikka
authors.forename: Risto
authors.initials: R
authors.lastname: Härkönen
authors.forename: Matti
authors.initials: M
authors.lastname: Luotolahti
authors.forename: Ronald
authors.initials: R
authors.lastname: Borra
authors.forename: Jan
authors.initials: J
authors.lastname: Sundell
authors.forename: Juhani
authors.initials: J
authors.lastname: Knuuti
authors.forename: Pirjo
authors.initials: P
authors.lastname: Nuutila
mesh_terms: D000368:Aged; D003324:Coronary Artery Disease / Q000150:complications* / Q000188:drug therapy*; D003331:Coronary Vessels / Q000187:drug effects; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000188:drug therapy*; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use; D007328:Insulin / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000188:drug therapy; D014664:Vasodilation / Q000187:drug effects
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin