Non-invasive magnetic resonance imaging assessment of myocardial changes and the effects of angiotensin-converting enzyme inhibition in diabetic rats

• Published in: The Journal of physiology Vol. 538; no. 2; pp. 541 - 553
• Main Authors: Al‐Shafei, Ahmad I. M., Wise, R. G., Gresham, G. A., Bronns, G., Carpenter, T. A., Hall, L. D., Huang, Christopher L.‐H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK The Physiological Society 15-01-2002; Blackwell Publishing Ltd; Blackwell Science Inc
• Subjects: Angiotensin-Converting Enzyme Inhibitors - pharmacology; Animals; Captopril - pharmacology; Diabetes Mellitus, Experimental - pathology; Diabetes Mellitus, Experimental - physiopathology; Heart - drug effects; Heart - physiopathology; Hypertrophy, Left Ventricular - prevention & control; Hypertrophy, Right Ventricular - prevention & control; Magnetic Resonance Imaging, Cine; Male; Myocardium - pathology; Organ Size - drug effects; Rats; Rats, Wistar; Research Papers
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/jphysiol.2001.012856

A non-invasive cine magnetic resonance imaging (MRI) technique was developed to allow, for the first time, detection and characterization
of chronic changes in myocardial tissue volume and the effects upon these of treatment by the angiotensin-converting enzyme
(ACE) inhibitor captopril in streptozotocin (STZ)-diabetic male Wistar rats. Animals that had been made diabetic at the ages
of 7, 10 and 13 weeks and a captopril-treated group of animals made diabetic at the age of 7 weeks were scanned. The findings
were compared with the results from age-matched controls. All animal groups ( n = 4 animals in each) were consistently scanned at 16 weeks. Left and right ventricular myocardial volumes were reconstructed
from complete data sets of left and right ventricular transverse sections which covered systole and most of diastole using
twelve equally incremented time points through the cardiac cycle. The calculated volumes remained consistent through all twelve
time points of the cardiac cycle in all five experimental groups and agreed with the corresponding post-mortem determinations.
These gave consistent myocardial densities whose values could additionally be corroborated by previous reports, confirming
the validity of the quantitative MRI results and analysis. The myocardial volumes were conserved in animals whose diabetes
was induced at 13 weeks but were significantly increased relative to body weight in animals made diabetic at 7 and 10 weeks.
Captopril treatment, which was started immediately after induction of diabetes, prevented the development of this relative
hypertrophy in both the left and right ventricles. We have thus introduced and validated quantitative MRI methods in a demonstration,
for the first time, of chronic myocardial changes in both the right and left ventricles of STZ-diabetic rats and their prevention
by the ACE inhibitor captopril.