Altered myocardial microvascular 3D architecture in experimental hypercholesterolemia.
BACKGROUND
Experimental hypercholesterolemia (HC) impairs intramyocardial microvascular function. However, whether this is associated with alterations in microvascular architecture remained unknown. Using a novel 3D micro-CT scanner, we tested the hypothesis that HC is associated with an alteration in the microvascular architecture.


RESULTS
Pigs were euthanized after 12 weeks of either normal (n=6) or 2% HC (n=6) diet. The hearts were excised and the coronary arteries injected with a radiopaque contrast material. Myocardial samples were scanned with micro-CT, and 3D images were reconstructed with 21-microm cubic voxels. The myocardium was tomographically subdivided into subepicardium and subendocardium, and microvessels (<500 microm in diameter) were counted in situ within each region. In the subendocardium of HC pigs, the intramyocardial density of microvessels was significantly higher than in normal animals (1221.4+/-199.7 versus 758.3+/-90.8 vessels/cm(3), P:<0.05) because of an increase in the number of microvessels <200 microm in diameter (1214.4+/-199.7 versus 746. 6+/-101.5 vessels/cm(3), P:<0.05). The subepicardial vascular density was similar in both groups.


CONCLUSIONS
-HC has differential effects on the spatial density of the subendocardial microvasculature that may play a role in regulation and/or spatial distribution of myocardial blood flow. This study also demonstrates the feasibility of studying myocardial microvascular architecture with micro-CT in pathophysiological states.
Rodriguez-Porcel
M
M
Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.
Lerman
A
A
Ritman
E L
EL
Wilson
S H
SH
Best
P J
PJ
Lerman
L O
LO
D000818:Animals; D002196:Capillaries / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D006321:Heart; D006937:Hypercholesterolemia / Q000473:pathology*; D008833:Microcirculation; D013552:Swine; D014057:Tomography, X-Ray Computed