Photocrosslinking of Adventitial Collagen in the Porcine Abdominal Aorta: A Preliminary Approach to a Strategy for Prevention of Aneurysmal Rupture

Abstract

This study was aimed at generating data for designing a potential method to prevent the rupture of the abdominal aortic aneurysm (AAA). We found that the mechanical strength and stiffness of blood vessel walls was enhanced by the crosslinking of adventitial collagen through a photochemical process promoted by ultraviolet-A (UV-A) radiation. The experiments were carried out on samples isolated from 25 normal porcine aortas. The adventitial layer was separated from the other layers and exposed to UV radiation of 365-nm wavelength, in the presence of a riboflavin compound as the photosensitizer. Mechanical testing of 30 specimens, prior to and after exposure, indicated an increase in both strength (ultimate stress) and stiffness (Young’s modulus) of the adventitial specimens following irradiation. The crosslinking process also led to an enhanced resistance to experimental collagenolysis, as determined on six specimens. At this phase of conceptual design, we suggest that by applying this method to an aneurysmal dilated wall region, the stabilization of tunica adventitia may delay or prevent the rupture of the aneurysm and, with further investigation and refinement, can become a therapeutic strategy for arresting the progression of AAA.