Modelling Lymphatic and blood capillary patterning

Angiogenesis and lymphangiogenesis, the formation of new blood or lymphatic vessels from preexisting ones, are important biological processes associated with diverse physiological processes, tissue repair and pathologies, such as cancer. Much progress has been made in recent years in identifying molecules specifically expressed on blood and lymphatic vessels and in the setting up of models of angiogenesis and lymphangiogenesis. In this review, we describe the most common in vitro models of (lymph)angiogenesis that have proven suitable for investigating angiogenic and lymphatic biology, and offer alternatives to animal experimentation. Their rationales, limitations and applications in biomedical research are discussed. A special emphasis will be given on ring assays that provide excellent recapitulation of various steps of (lymph)angiogenesis. The aortic ring assay has become the most widely used methods to study in vitro angiogenesis, and the recently set up lymphatic ring assay provides the opportunity to extend the in vitro studies to lymphangiogenesis.