Background and Purpose: Vasa vasorum, which constitutes a network of microvasculature, plays a nutritive and drainable role in vessel walls of arteries. The existence of vasa vasorum within brain vasculature is rarely reported. Based on a series of cerebral artery specimens, we aimed to describe the distribution features of vasa vasorum among intracranial arteries, including middle cerebral arteries (MCAs), basilar arteries (BAs) and vertebral arteries (VAs) and potential effects of vasa vasorum on atherosclerosis morphology.
Methods: One hundred and fifty- seven arteries (64 MCAs, 32 Bas and 61 VAs) were obtained from consecutively recruited 32 autopsy cases aged 45 years or above. Routine histology and immunostaining processing were performed to identify the presence of adventitial vasa vasorum and to study the phenotypes and specific components of intracranial atherosclerotic lesions.
Results: Among 157 intracranial cerebral arteries, adventitial vasa vasorum were present most frequently in the vertebral arteries (77%), followed by basilar arteries (44%) and middle cerebral arteries (20%). Arteries with adventitial vasa vasorum had greater thickness of tunica adventitia (0.10±0.06 mm vs. 0.06±0.03 mm, p < 0.001) and larger size in diameters (3.41± 0.73 mm vs. 2.97± 0.66 mm, p < 0.001). The occurrence of adventitial vasa vasorum correlated with high frequency of complicated plaques and higher rate of concentric atherosclerotic lesions (70% vs. 36%, p < 0.001).
Conclusion: For the first time, our study demonstrated the presence of adventitial vasa vasorum within brain vasculature, especially at vertebral arteries. The correlations between adventitial vasa vasorum and intraplaque hemorrhage, inflammation and calcification suggest that adventitial vasa vasorum may serve as a predictor of unstable atherosclerotic lesions. Further studies are required to explore the biological behavior of adventitial vasa vasorum within cerebral arteries.