Epigallocatechin gallate (EGCG) partially prevents elastase-induced mechanical and microstructural changes in the mouse ascending aorta in vitro

Elastic fibers are critical for proper mechanical function of large arteries such as the aorta. Fragmentation, degradation, or reduced amounts of elastic fibers are associated with aortic diseases such as stiffening-induced hypertension and aneurysms. Epigallocatechin gallate (EGCG) is a plant-based polyphenol that has been shown to increase elastic fiber synthesis, preventing stiffening-induced hypertension and alleviating abdominal aortic aneurysms. EGCG is similar in structure to another polyphenol, pentagalloyl glucose, that has been shown to increase elastic fiber synthesis and prevent elastic fiber degradation. The effects of EGCG on elastic fiber degradation have not been previously investigated. In this study, elastase (ELA) was used to degrade elastic fibers in the mouse ascending aorta and the preventative and restorative potential of EGCG was determined by characterizing the passive, circumferential mechanical behavior and microstructural organization of the aortic wall. EGCG treatment alone had no effect on the mechanical behavior or microstructural organization of the aortic wall. ELA treatment alone resulted in increased aortic diameter, altered aortic compliance, reduced low modulus, increased high modulus, and decreased density of the elastic fiber layers in the wall. EGCG as a preventative treatment before ELA partially prevented the changes in mechanical behavior and wall structure observed with ELA. EGCG as a restorative treatment after ELA did not prevent the changes in mechanical behavior and wall structure associated with ELA. These results suggest that EGCG may be an effective preventative pharmaceutical treatment option for cardiovascular diseases that are characterized by elastic fiber degradation.