Lymphangiogenesis promotes inflammation and neointimal hyperplasia after adventitia removal in the rat carotid artery.

Lymphatic vessels exist in adventitia in the atherosclerotic coronary artery and play an important role in the inflammatory and immune response. After adventitia removal, the carotid wall of rat model showed significantly increased ratio of intimal to medial area (I/M ratio), the number of adventitial lymphatic vessels (Ad-LV) and microvessels (Ad-MV), and macrophage index and expression of VEGF-C, VEGFR-3, PDGF-B and PDGFR-beta. The I/M ratio was significantly correlated with Ad-LV and macrophage index but not Ad-MV. These results suggest that adventitial lymphangiogenesis is stimulated by growth factors released by inflammatory cells in vasculature after adventitia removal, and these neogenetic lymph vessels in turn promote intimal inflammation and hyperplasia, probably via delivery and activation of inflammatory cells.