title: Effect of streptozotocin-induced diabetes on myocardial blood flow reserve assessed by myocardial contrast echocardiography in rats.
abstract: The role of structural and functional abnormalities of small vessels in diabetes cardiomyopathy remains unclear. Myocardial contrast echocardiography allows the quantification of myocardial blood flow at rest and during dipyridamole infusion. The aim of the study was to determine the myocardial blood flow reserve in normal rats compared with streptozotocin-induced diabetic rats using contrast echocardiography.
  
  
  METHODS
  We prospectively studied 40 Wistar rats. Diabetes was induced by intravenous streptozotocin in 20 rats. All rats underwent baseline and stress (dipyridamole: 20 mg/kg) high power intermittent imaging in short axis view under anaesthesia baseline and after six months. Myocardial blood flow was determined and compared at rest and after dipyridamole in both populations. The myocardial blood flow reserve was calculated and compared in the 2 groups. Parameters of left ventricular function were determined from the M-mode tracings and histological examination was performed in all rats at the end of the study.
  
  
  RESULTS
  At six months, myocardial blood flow reserve was significantly lower in diabetic rats compared to controls (3.09 +/- 0.98 vs. 1.28 +/- 0.67 ml min-1 g-1; p < 0.05). There were also a significant decrease in left ventricular function and a decreased capillary surface area and diameter at histology in the diabetic group.
  
  
  CONCLUSIONS
  In this animal study, diabetes induced a functional alteration of the coronary microcirculation, as demonstrated by contrast echocardiography, a decrease in capillary density and of the cardiac systolic function. These findings may offer new insights into the underlying mechanisms of diabetes cardiomyopathy.
authors.affiliation: Cardiology Department, UZ Brussel, VUB, Brussels, Belgium. bcosyns@skynet.be
authors.forename: Bernard
authors.initials: B
authors.lastname: Cosyns
authors.forename: Steven
authors.initials: S
authors.lastname: Droogmans
authors.forename: Sophie
authors.initials: S
authors.lastname: Hernot
authors.forename: Céline
authors.initials: C
authors.lastname: Degaillier
authors.forename: Christian
authors.initials: C
authors.lastname: Garbar
authors.forename: Caroline
authors.initials: C
authors.lastname: Weytjens
authors.forename: Bram
authors.initials: B
authors.lastname: Roosens
authors.forename: Danny
authors.initials: D
authors.lastname: Schoors
authors.forename: Tony
authors.initials: T
authors.lastname: Lahoutte
authors.forename: Philippe R
authors.initials: PR
authors.lastname: Franken
authors.forename: Guy
authors.initials: G
authors.lastname: Van Camp