Abstract 254: Perivascular Adipose Tissues Anatomically Communicate with Atherosclerotic Lesions via Vasa Vasorum; Possible Link of Adipo-vascular Axis
Background: Recent evidence indicates that adipose tissues secret various humoral factors called as adipocytokines. Adipocytokines play crucial roles in cardiovascular system under physiological and pathological conditions. It was documented that atherosclerotic lesion formation is associated with adventitial neovascularization as vasa vasorum. Vasa vasorum has been assumed as conduits which supply oxygen and nutrients into the plaque, thereby contributing to lesion progression. Usually, arteries are surrounded by abundant periadventitial fat tissues, which have been suggested to be important to maintain vascular homeostasis. Here, we investigated anatomical communication between perivasvular fat tissues and atherosclerotic plaques.
Method and Results: 80 to 110-week-old male ApoE deficient mice had advanced atherosclerotic lesions in the aorta, on which immunofluorescence staining was performed against CD31 with 40 – 60μm thick frozen sections. A three-dimensional reconstruction of confocal images revealed that microvessels invaded from the periadventitial adipose tissue into the atherosclerotic lesion of the aorta. Furthermore, an electron microscopic observation of the vascular corrosion casts with resin demonstrated the segmental vascular networks or plexus in close vicinity to the atherosclerotic lesions. Periadventitial fat tissues contained abundant microvessels that extended to the atherosclerotic lesions of the aorta
(n=3). Direct communication between perivascular fat tissues and aorta was not noted in the earlier atherosclerotic lesions of 37-week-old ApoE-deficient mice.
Conclusion: Perivascular fat tissues contain microvascular network that anatomically communicates with atherosclerotic lesions. Our finding suggests that adipocytokines secreted by periadventitial adipose tissue may have a direct access to adjacent vessel wall and play a role in the pathogenesis of atherosclerosis.