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.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.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.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.
Highlights
Diabetic cardiomyopathy is known to develop in humans in the absence of coronary or hypertensive disease [1]
Other symptoms frequently associated with diabetic state such as lower body weights, polyuria, polyphagia were observed in the diabetic rats
The percentage capillary area and capillary diameters were lower in the diabetic rats compared to controls
Summary
Diabetic cardiomyopathy is known to develop in humans in the absence of coronary or hypertensive disease [1]. Recent studies have suggested abnormalities in coronary small vessels in humans [4,5], similar to dilated cardiomyopathy [6,7], and in spontaneously diabetic rats [8], the association between vascular and myocardial disease in diabetes remains controversial. Myocardial contrast echocardiography (MCE) has been shown to be a useful tool to estimate the myocardial blood flow (MBF) at rest and during stress in dogs and humans [9,10,11,12,13]. Echocardiography has been recently adapted to image hearts of rodents [14] and MCE has shown a good correlation of MBF estimates with microspheres technique [15]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
