**7. Angiogenic growth factors in ADPKD liver**

Expression of angiogenic growth factors have also been demonstrated in cystic liver from human ADPKD patients and also in animal models of PKD.Upregulated expression of Ang-1, Ang-2 and their Tie-2 receptor has been demonstrated in the cholangiocytes that line hepatic cysts in ADPKD, supporting a role for angiogenic growth factors in liver cystogenesis (Fabris et al., 2006). Moreover, cyst fluid from hepatic cysts has been shown to contain VEGF (Amura et al., 2008; Nichols et al., 2004,). In a subsequent animal study factors secreted by liver cyst epithelia were shown to promote endothelial cell proliferation and development (Brodsky et al., 2009).
