Effect of Glycation on Interlamellar Bonding of Arterial Elastin

Background Interlamellar bonding in the arterial wall is often compromised by cardiovascular diseases. However, several recent nationwide and hospital-based studies have uniformly reported reduced risk of thoracic aortic dissection in patients with diabetes. As one of the primary structural constituents in the arterial wall, elastin plays an important role in providing its interlamellar structural integrity. Objective The purpose of this study is to examine the effects of glycation on the interlamellar bonding properties of arterial elastin. Methods Purified elastin network was isolated from porcine descending thoracic aorta and incubated in 2 M glucose solution for 7, 14 or 21 days at 37 °C. Peeling and direct tension tests were performed to provide complimentary information on understanding the interlamellar layer separation properties of elastin network with glycation effect. Peeling tests were simulated using a cohesive zone model (CZM). Multiphoton imaging was used to visualize the interlamellar elastin fibers in samples subjected to peeling and direct tension. Results Peeling and direct tension tests show that interlamellar energy release rate and strength both increase with the duration of glucose treatment. The traction at damage initiation estimated for the CZM agrees well with the interlamellar strength measurements from direct tension tests. Glycation was also found to increase the interlamellar failure strain of arterial elastin. Multiphoton imaging confirmed the contribution of radially running elastin fibers to resisting dissection. Conclusions Nonenzymatic glycation reduces the propensity of arterial elastin to dissection. This study also suggests that the CZM effectively describes the interlamellar bonding properties of arterial elastin.