Background Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant inherited syndrome of dysregulated angiogenesis presenting with arteriovenous malformations in multiple organ systems. Despite the significant complications associated with HHT, FDA-approved therapeutic options remain unavailable. In HHT, bypassing the ACVRL1 mutation is critical to restore downstream TGF-β signaling. Extracellular vesicle (EVs) mediated delivery of recombinant proteins offer a pioneering approach, in biocompatible fashion, to treat dysregulated angiogenesis in HHT. Engineered Bone Morphogenic Protein 2 and 7 extracellular vesicles (BMP2/7-EV) may offer a potential therapeutic approach for HHT by bypassing the defective ACVRL1 and reactivating SMAD signaling. Methods We utilized an ex ovo chicken chorioallantoic membrane (CAM) model to investigate the effects of BMP2/7-EVs. Fertilized eggs were incubated at 37C and transferred to weigh boats on developmental day 3. On day 9, each respective treatment was applied: 50 µL of either PBS (vehicle control), ALK1-Fc (500 ng/mL), BMP2/7-EV (1.78e8 particles/ml), or a combination of BMP2/7-EV (1.78e8 particles/ml) and ALK1-Fc (500 ng/mL) onto three different areas of each embryo. Microscopy at days 9 through 11 was used to document the vessel development. IKOSA software was used to generate images quantifying branch number. Statistical significance compared to control was determined by two-way ANOVA with Tukey post hoc analysis. Results ALK1-Fc treatment at concentrations above 100ng/mL induced hypervascularization, demonstrated by an increase vascular branching in the native ex ovo CAM model. This effect was most pronounced at 500ng/mL. BMP2/7-EV treatment of native ex ovo CAM model and ALK1-Fc CAM model mimicking HHT behavior showed a trend towards vascular regression although the differences were not statistically significant in this pilot study. Conclusion The CAM assay model demonstrates promising potential for HHT research, providing a cost-effective and ethical alternative to mammalian models, allowing direct visualization of vascular changes, and offering a platform for testing angiogenic modulators. While the BMP2/7-EV treatment showed a trend towards normalizing vessel formation in the ALK1-Fc model mimicking HHT, further optimization and repeated experiments are necessary to draw definitive conclusions. This approach not only enhances our understanding of HHT pathophysiology but also paves the way for the development of targeted therapies for HHT patients, potentially improving their quality of life. Future studies will focus on refining the model, conducting more extensive studies to ensure the reproducibility of our results and exploring how various factors influence vessel formation in our model.