title: Testing an unusual in vivo vessel network model: a method to study angiogenesis in the colonial tunicate Botryllus schlosseri.
abstract: Tunicates are the closest relatives to vertebrates and include the only chordate species able to reproduce both sexually and asexually. The colonial tunicate Botryllus schlosseri is embedded in a transparent extracellular matrix (the tunic) containing the colonial circulatory system (CCS). The latter is a network of vessels external to zooids, limited by a simple, flat epithelium that originated from the epidermis. The CCS propagates and regenerates by remodelling and extending the vessel network through the mechanism of sprouting, which typically characterises vertebrate angiogenesis. In exploiting the characteristics of B. schlosseri as a laboratory model, we present a new experimental and analysis method based on the ability to obtain genetically identical subclones representing paired samples for the appropriate quantitative outcome statistical analysis. The method, tested using human VEGF and EGF to induce angiogenesis, shows that the CCS provides a useful in vivo vessel network model for testing the effects of specific injected solutes on vessel dynamics. These results show the potentiality of B. schlosseri CCS as an effective complementary model for in vivo studies on angiogenesis and anticancer therapy. We discuss this potentiality, taking into consideration the origin, nature, and roles of the cellular and molecular agents involved in CCS growth.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Gasparini
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Caicci
authors.affiliation: CORIT-Consortium for Research in Organ Transplantation, Legnaro, 35020 Padova, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Rigon
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Zaniolo
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Manni
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000166:cytology / Q000254:growth & development*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D009024:Morphogenesis / Q000502:physiology*; D018919:Neovascularization, Physiologic; D014561:Urochordata / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D042461:Vascular Endothelial Growth Factor A; D004815:Epidermal Growth Factor