SUMMARY Work performed during the last decade revealed the first molecular insights into lymphatic vascular biology. Some of those findings build the foundation for the studies to be pursued within this novel proposal. The goals are to take advantage of the expertise, tools and animal models my laboratory generated to investigate how lymphoangiocrine signals produced by cardiac associated lymphatic endothelial cells contribute to heart growth during development and cardiac repair after MI. This work should have an important impact in the way we think about traditional lymphatic functional roles, as well as in the way we treat cardiac disorders.