The AAPS 101st Annual Meeting

Micropuncture Induced Scaffold Vascularization and Macrophage Quantification Across Vascular Origins

Purpose

•Vascularization is a major barrier to tissue engineering and macrophages are believed to be integral.

•We have developed a pro-angiogenic microsurgical approach.

•In micropuncture (MP), the recipient blood vessel wall is disrupted providing an direct route for macrophage extravasation.

•Previously, we evaluated adjacent collagen scaffold vascularization with concurrent MP of both the artery and vein.

•However, the individual vascular contribution is unknown.

•Here, we evaluated scaffold vascularization and macrophage accumulation across vascular origins.

•We hypothesized that concurrent artery/vein MP results in greatest scaffold macrophage infiltration and vascularization.

Methods

•MP was tested in the rat femoral artery (MPA), vein (MPV), artery and vein (MPA/V), and no MP (control).

•MPs were performed using a 60-um diameter needle at defined intervals just prior to collagen scaffold implantation.

•At post-operative day (POD) 3 and 10, scaffold explants were analyzed using whole mount angiography and histology.

•Vascular density was computed using artificial intelligence (AI).

•Endothelial cell (EC) and macrophage infiltration were quantified.

Results

•Vascular density (Figure 1) and EC infiltration (Figure 2) were greatest in MPA/V samples at POD 3 and 10.

•Scaffold macrophage accumulation was highest with MPV followed by MPA/V at both POD 3 and 10 (Figure 3).

Conclusions

•MP creates a localized pro-angiogenic environment.

•Although MPA/V led to greatest vascularization, it is noteworthy that MPV is also substantially pro-angiogenic.

•This suggests that the vein drives both the cellular and vascular changes in MP.

•MP is a tailored surgical approach for angiogenic induction that could be beneficial to reconstructive surgery and tissue engineering.

Micropuncture Induced Scaffold Vascularization And Macrophage Quantification Across Vascular Origins