Ultrasound-guided photoacoustic imaging-directed re-endothelialization of acellular vasculature leads to improved vascular performance.

As increasing effort is dedicated to investigating the regenerative capacity of decellularized tissues, research has progressed to recellularizing these tissues prior to implantation. The delivery and support of cells seeded throughout acellular scaffolds are typically conducted through the vascular axis of the tissues. However, it is unclear how cell concentration and injection frequency can affect the distribution of cells throughout the scaffold. Furthermore, what effects re-endothelialization have on vascular patency and function are not well understood. We investigated the use of ultrasound-guided photoacoustic (US/PA) imaging as a technique to visualize the distribution of microvascular endothelial cells within an optimized acellular construct upon re-endothelialization and perfusion conditioning. We also evaluated the vascular performance of the re-endothelialized scaffold using quantitative vascular corrosion casting (qVCC) and whole-blood perfusion. We found US/PA imaging was an effective technique to visualize the distribution of cells. Cellular retention following perfusion conditioning was also detected with US/PA imaging. Finally, we demonstrated that a partial recovery of vascular performance is possible following re-endothelialization—confirmed by fewer extravasations in qVCC and improved blood clearance following whole-blood perfusion.

随着越来越多的努力致力于研究脱细胞组织的再生能力，研究已经进展到在植入前对这些组织进行再细胞化。在无细胞支架中播种的细胞的输送和支持通常通过组织的血管轴进行。然而，细胞浓度和注射频率如何影响细胞在支架中的分布尚不清楚。此外，再内皮化对血管通畅性和功能有何影响也不太清楚。我们研究了使用超声引导光声（US/PA）成像技术，以在再内皮化和灌注调节后可视化优化的无细胞构建体中微血管内皮细胞的分布。我们还使用定量血管腐蚀铸型（qVCC）和全血灌注评估了再内皮化支架的血管性能。我们发现US/PA成像技术是一种可视化细胞分布的有效技术。灌注调节后的细胞保留也可通过US/PA成像检测到。最后，我们证明了再内皮化后血管性能有可能部分恢复——这通过qVCC中渗出减少以及全血灌注后血液清除改善得到证实。