Abstract
Purpose :
The angiopoietin/tyrosine kinase with immunoglobulin-like domains (Ang/Tie) pathway is a key regulator of vascular stability, angiogenesis, and inflammation in the retinal vasculature. Results from the phase 3 trials of faricimab support the potential for dual Ang-2/vascular endothelial growth factor (VEGF)-A pathway inhibition to promote vascular stability and extend treatment durability for nAMD and DME. We assessed the role of Ang-2 in vascular destabilization using primary human vasculature models.
Methods :
A 3D human inner blood-retinal barrier (iBRB) microvascular network was developed on a microfluidic chip with primary human retinal endothelial cells (ECs), pericytes (PCs), and astrocytes (ACs); effects of exogenous Ang-1, Ang-2, and anti–Ang-2/VEGF-A antibody on cell interactions were evaluated using immunocytochemistry and quantified using 3D image analysis based on a custom Python script. To investigate phenotypic changes after Tie2 receptor activation, primary human retinal ECs grown on 2D or 3D microvascular networks were treated with Ang-1, vascular endothelial protein tyrosine phosphatase, Ang-2, and anti–Ang-2/VEGF-A antibody. Cellular and vascular morphology will be correlated with Tie2 receptor activation status.
Results :
Preliminary data suggest that addition of Ang-1 to the iBRB-on-a-chip increased PC coverage of ECs compared with Ang-2 and basal medium. In addition, the interstitial space between ECs and PCs decreased with Ang-1 and increased with Ang-2 vs basal medium. AC coverage of ECs increased with Ang-1 and decreased with Ang-2 vs basal medium. Sequencing of control vs Ang-2–treated iBRB is ongoing to understand these changes at the transcriptional level; preliminary data suggest Ang-2 might modulate adhesion and extracellular matrix remodeling factors. The effects of anti–Ang-2/VEGF-A antibody on the iBRB-on-a-chip are being investigated. The results from Tie-2 activation studies in primary human retinal ECs will be presented.
Conclusions :
We have used iBRB-on-a-chip to investigate the effect of Ang-1 and Ang-2 on vascular morphology and function. Preliminary data suggest Ang-1 promoted PC/AC adhesion to ECs, whereas random PC organization was observed with Ang-2. Experiments are ongoing to fully characterize iBRB response and understand the role of dual Ang-2/VEGF-A pathway inhibition, which could support clinical development of nAMD and DME treatments.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.