Vascular Biology |
From the National Research Laboratory of Vascular Biology and Department of Biological Sciences (K.E.K., C-H.C., H-Z.K., G.Y.K.), Korea Advanced Institute of Science and Technology, Daejeon, Korea; Cardiovascular Research Institute (P.B., D.M.M.), Comprehensive Cancer Center, and Department of Anatomy, University of California, San Francisco, Calif.
Correspondence to Gou Young Koh, Department of Biological Sciences, KAIST, 373-1, Guseong-dong, Daejeon, 305-701, Republic of Korea. E-mail gykoh{at}kaist.ac.kr
Objective We investigated and compared the in vivo effects of all four angiopoietins (COMP-Ang1, Ang2, Ang3, and Ang4) on blood and lymphatic vascular remodeling in adult mice. We analyzed the microvasculature of trachea and ear skin, and compared quiescent skin microvasculature with that during wound healing.
Methods and Results We were able to achieve similar levels of relatively long-term and sustained circulating expression of each angiopoietin using an adenoviral delivery system. Two weeks after treatment, we observed tracheal blood and lymphatic vascular enlargement, and lymphatic filopodia formation, with the following order of potency: COMP-Ang1>Ang3=Ang4>Ang2. Co-treatment with Ang2 attenuated Ang1-induced tracheal blood and lymphatic remodeling. In the normal ear skin, all angiopoietins induced blood vessel enlargement, whereas none induced lymphatic vascular remodeling. However, in the healing margin of ear skin wounds, all angiopoietins strongly induced lymphatic vascular enlargement and formation of lymphatic sprouts and filopodia, while they potentiated blood vascular enlargement. Co-treatment of Ang2 with Ang1 produced an additive effect on these changes.
Conclusion This study, one of the first to our knowledge to characterize the in vivo actions of all 4 angiopoietins, may expand the current concepts for use of angiopoietins for therapeutic angiogenesis and lymphangiogenesis.
Angiopoietins 1, 2, 3, and 4 elicited different amounts of blood and lymphatic vascular remodeling in normal and wound healing tissues. COMP-Ang1 and Ang2 given together produced an amount of vascular remodeling in normal vessels intermediate between the individual angiopoietins but had additive effects on vascular remodeling in skin wounds.
Key Words: angiogenesis angiopoietin lymphangiogenesis Tie2 vascular remodeling
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