Rapamycin improves TIE2-mutated venous malformation in murine model and human subjects
Elisa Boscolo, … , Joyce Bischoff, Laurence M. Boon
Elisa Boscolo, … , Joyce Bischoff, Laurence M. Boon
Published August 10, 2015
Citation Information: J Clin Invest. 2015;125(9):3491-3504. https://doi.org/10.1172/JCI76004.
View: Text | PDF
Research Article Genetics

Rapamycin improves TIE2-mutated venous malformation in murine model and human subjects

Abstract

Venous malformations (VMs) are composed of ectatic veins with scarce smooth muscle cell coverage. Activating mutations in the endothelial cell tyrosine kinase receptor TIE2 are a common cause of these lesions. VMs cause deformity, pain, and local intravascular coagulopathy, and they expand with time. Targeted pharmacological therapies are not available for this condition. Here, we generated a model of VMs by injecting HUVECs expressing the most frequent VM-causing TIE2 mutation, TIE2-L914F, into immune-deficient mice. TIE2-L914F–expressing HUVECs formed VMs with ectatic blood-filled channels that enlarged over time. We tested both rapamycin and a TIE2 tyrosine kinase inhibitor (TIE2-TKI) for their effects on murine VM expansion and for their ability to inhibit mutant TIE2 signaling. Rapamycin prevented VM growth, while TIE2-TKI had no effect. In cultured TIE2-L914F–expressing HUVECs, rapamycin effectively reduced mutant TIE2-induced AKT signaling and, though TIE2-TKI did target the WT receptor, it only weakly suppressed mutant-induced AKT signaling. In a prospective clinical pilot study, we analyzed the effects of rapamycin in 6 patients with difficult–to-treat venous anomalies. Rapamycin reduced pain, bleeding, lesion size, functional and esthetic impairment, and intravascular coagulopathy. This study provides a VM model that allows evaluation of potential therapeutic strategies and demonstrates that rapamycin provides clinical improvement in patients with venous malformation.

Authors

Elisa Boscolo, Nisha Limaye, Lan Huang, Kyu-Tae Kang, Julie Soblet, Melanie Uebelhoer, Antonella Mendola, Marjut Natynki, Emmanuel Seront, Sophie Dupont, Jennifer Hammer, Catherine Legrand, Carlo Brugnara, Lauri Eklund, Miikka Vikkula, Joyce Bischoff, Laurence M. Boon

×

Figure 3

TIE2-TKI and rapamycin effects on murine VMs.

Options: View larger image (or click on image) Download as PowerPoint
TIE2-TKI and rapamycin effects on murine VMs. (A) Pretreatment plus i.p....
(A) Pretreatment plus i.p. injection schematic. (B) Representative murine VM lesion explants at day 16. Top row: vehicle; middle row: TIE2-TKI; bottom row: rapamycin. Images taken from fixed distance. (C) HUVEC-TIE2-L914F lesional area measured by caliper every 2 days for 16 days. Data expressed as mean ± SEM, t test (n = 5 mice with 2 lesions/group). (D) Vascular volume at day 15 measured by analysis of color Doppler 3D image stacks. Data expressed as single values for each lesion (n = 5 mice with 2 lesions/group); medians shown by horizontal bars, Mann-Whitney U test. (E) Pretreatment schematic. (F) Representative murine VM lesion explants at day 16. Top row, DMSO; middle row, TIE2-TKI; bottom row, rapamycin. Images taken from fixed distance. (G) HUVEC-TIE2-L914F lesional area measured by caliper every 2 days for 16 days. Data expressed as mean ± SEM, t test (n = 5 mice with 2 lesions/group; shown is a representative experiment from 2 independent experiments). (H) Vascular volume at day 16 measured by analysis of color Doppler 3D image stacks. Data expressed as single values for each lesion; medians shown by horizontal bars, Mann-Whitney U test (n = 5 mice with 2 lesions/group; shown is a representative experiment from 2 independent experiments). (I) Representative images of VM sections immunostained for UEA-I (red), αSMA (green), and DAPI (blue). Arrows point to αSMA+ cells. Scale bar: 100 μM. (J) Quantification of luminal area occupied by UEA-I–stained blood vessels, expressed as percentage of total sectional area. Data expressed as mean ± SEM, t test (n = 5 fields/section, 7 mice analyzed/group). NS, P > 0.05. (K) Quantification of αSMA+ cells surrounding UEA-I–stained blood vessels. Data expressed as mean ± SEM (n = 5 fields/section, 7 mice analyzed/group). NS, P > 0.05.