Engineering Functional Vasculature in Decellularized Lungs Depends on Comprehensive Endothelial Cell Tropism.

Ifeolu Akinnola,Angela Panoskaltsis-Mortari,Douglas R Haase,Rachel E Blue,Ashley Lindsey,Michael J Ehrhardt,Daniel R Rossi,Carolyn Meyer,Max Johnson,Samuel Fogas,Andrew P Price,Doris A Taylor,Diego F Alvarez

doi:10.3389/fbioe.2021.727869

Abstract

Tissue engineering using decellularized whole lungs as matrix scaffolds began as a promise for creating autologous transplantable lungs for patients with end-stage lung disease and can also be used to study strategies for lung regeneration. Vascularization remains a critical component for all solid organ bioengineering, yet there has been limited success in generating functional re-endothelialization of most pulmonary vascular segments. We evaluated recellularization of the blood vessel conduits of acellular mouse scaffolds with highly proliferating, rat pulmonary microvascular endothelial progenitor cells (RMEPCs), pulmonary arterial endothelial cells (PAECs) or microvascular endothelial cells (MVECs). After 8 days of pulsatile perfusion, histological analysis showed that PAECs and MVECs possessed selective tropism for larger vessels or microvasculature, respectively. In contrast, RMEPCs lacked site preference and repopulated all vascular segments. RMEPC-derived endothelium exhibited thrombomodulin activity, expression of junctional genes, ability to synthesize endothelial signaling molecules, and formation of a restrictive barrier. The RMEPC phenotype described here could be useful for identifying endothelial progenitors suitable for efficient vascular organ and tissue engineering, regeneration and repair.

Highlights

The treatment of end-stage lung diseases requires lung transplantation, yet there is a severe shortage of available lungs for transplant
pulmonary arterial endothelial cells (PAECs), microvascular endothelial cells (MVECs), and rat pulmonary microvascular endothelial progenitor cells (RMEPCs) were assessed by flow cytometry to confirm the phenotypes perfused into the decellularized lungs
RMEPCs were negative for CD31 (PECAM-1), whereas PAECs and MVECs stained positively (Figure 2)

Summary

Introduction

The treatment of end-stage lung diseases requires lung transplantation, yet there is a severe shortage of available lungs for transplant. Tissue engineering using decellularized whole lungs as scaffolding might provide an opportunity to generate functional lungs for autologous transplant in patients for whom there is no other therapeutic alternative. Despite some advancements in lung tissue engineering (Petersen et al, 2010; Song et al, 2011; Calle et al, 2014; Ren et al, 2015; Balestrini et al, 2016), to date, the Endothelial Progenitor for Lung Bioengineering establishment of a functioning vasculature with low thrombogenicity and adequate barrier function has proven to be difficult, resulting in lung failure. Decellularized lungs provide the ideal biomimetic cues for appropriate cell localization, differentiation, and function. Such three-dimensional niches are conducive to physiological cell-matrix and cell-cell crosstalk, potentially enhancing the functionality and stability of engineered, transplantable organs

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