Thus, basal levels of PAI-1 in Eng-iKOe cells tend to be higher than those in control ECs (Table S2B), a finding compatible with the upregulated expression of the PAI-1 gene found in gene arrays of ECs derived from HHT patients (Fernandez-Lopez et al., 2007) and with increased ALK5 (TGFBR1) signaling in the absence of endoglin (Lebrin et al., 2004). This evidence concerns the gene SERPINE1 and hereditary hemorrhagic telangiectasia.