Associate Professor Wayne State University, United States
Introduction: Atherosclerosis is a chronic inflammatory disease which remains the primary cause of cardiovascular disease (CVD). The drugs administered to reduce low-density lipoproteins (LDLs) are effective but have no effect on the alarming prevalence of atherosclerosis. Given current therapies’ minimal effectiveness, it is imperative to understand the immune responses associated with atherosclerosis to curate new, effective therapeutics. Currently, atherosclerosis studies use mouse models for research, however these models lack human pathophysiology. Here, we present findings of developing a human tissue engineered blood vessel model with immunological mechanisms. LDL inundation causes endothelial activation, initiating atherosclerosis which in return initiates a cascade of immune responses. LDL uptake into the intima of the blood vessel is one of the first responses presented in human atherosclerosis, which is the basis of this preliminary in vitro human model of atherosclerosis.
Materials and
Methods: The tissue engineered vessels were created using a protocol created in our lab involving the formation of vascular tissue rings and stacking of the rings to create a tubular vessel. To replicate the anatomy of a human vessel, the tunica media was constructed using human aortic smooth muscle cells (HASMCs). The HASMCs were formed into vascular rings via our lab protocol, stacked onto a 3D printed post, and cultured for up to 1 month. The tissue engineered vessel was seeded with human aortic endothelial cells (HAECs) to create the tunica intima. A seeding device was created to ensure the total circumference of the tunica media was coated in endothelial cells. LDLs were inserted into the tissue engineered model to replicate the first vital pathological step of atherosclerosis. LDLs were introduced into the intima at various concentrations to determine the optimal concentration for the uptake of LDLs. To assess the uptake of LDLs by the engineered vessel, histological stains of H&E and Oil Red O were performed.
Results, Conclusions, and Discussions: Results &
Discussion: The optimization of the tissue engineered vessel protocol led to the identification of the desired concentration for LDL uptake into the engineered vessel wall. This improved protocol resulted in no cell toxicity or death. To validate the effects of LDL on endothelial cell (EC) activation, EC activation markers were screened, such as E-selectin. This study shows that immunological mechanisms can be reproduced in a tissue engineered vessel to replicate human pathophysiology.
Conclusion: The implementation of the LDLs into the tissue engineered vessel was successful. Due to the success, further investigation of the effects of LDLs on EC activation will continue. These positive results allow for the continuation of this project involving the addition of monocytes and their uptake into the intima. With the addition of the multiple pathological step of atherosclerosis, the engineered vessel replicates the major components of human pathophysiology. This work will allow for a more accurate and novel tool for the development of new therapies for the prevention of atherosclerosis.
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