Coronary vasa vasorum neovascularization precedes epicardial endothelial dysfunction in experimental hypercholesterolemia.
OBJECTIVE
Experimental hypercholesterolemia is associated with vasa vasorum neovascularization, unknown to occur before or after initial lesion formation. Thus, this study was performed to determine the temporal course of neovascularization of coronary vasa vasorum in relation to endothelial dysfunction, a hallmark of early atherosclerosis.


METHODS
Female domestic pigs were fed a normal diet (Group 1), a hypercholesterolemic diet for 2 and 4 weeks (Group 2), or a hypercholesterolemic diet for 6 and 12 weeks (Group 3). In vitro analysis of relaxation response to bradykinin served as an index for epicardial endothelial function. Spatial pattern and density of coronary vasa vasorum were assessed by three-dimensional microscopic computed tomography.


RESULTS
Relaxation response of coronary arteries to bradykinin was normal in both Group 1 (93+/-6%) and Group 2 (89+/-7%) but impaired in Group 3 (71+/-11%; P<0.05 vs. Group 1 and 2). In contrast, density of coronary vasa vasorum was significantly higher in both Group 2 (4.88+/-2.45 per-mm(2)) and Group 3 (4.50+/-1.37 per-mm(2)) compared to Group 1 (2.97+/-1.37 per-mm(2); P<0.05 vs. Group 2 and 3).


CONCLUSIONS
This study demonstrates that coronary vasa vasorum neovascularization occurs within the first weeks of experimental hypercholesterolemia and prior to the development of endothelial dysfunction of the host vessel, suggesting a role for vasa vasorum neovascularization in the initial stage of atherosclerotic vascular disease.
Herrmann
J
J
Division of Cardiovascular Diseases, Mayo Clinic Rochester, 200 First Street S.W., Rochester, MN 55905, USA.
Lerman
L O
LO
Rodriguez-Porcel
M
M
Holmes
D R
DR
Richardson
D M
DM
Ritman
E L
EL
Lerman
A
A
D000704:Analysis of Variance; D000818:Animals; D001920:Bradykinin; D003331:Coronary Vessels / Q000187:drug effects; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006937:Hypercholesterolemia / Q000473:pathology* / Q000503:physiopathology; D009389:Neovascularization, Pathologic; D013552:Swine; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014651:Vasa Vasorum / Q000473:pathology*; D014665:Vasodilator Agents
D014665:Vasodilator Agents; D001920:Bradykinin