Multiphoton imaging of the effect of monosaccharide diffusion and formation of fluorescent advanced end products in porcine aorta

Prolonged exposure of tissues to elevated blood sugar levels lead to the formation of advanced glycation end products (AGEs), thus contributing to diabetic complications. Since the vascular system is in immediate contact with blood, diabetic effects on aorta is a major health concern. However, the relative effect of the diffusion of sugar molecular through the vascular wall and the rate of AGE formation is not known. In this study, we aim to address this issue by incubating excised porcine aorta in D-glucose, D-galactose, and D-fructose solutions for different periods. The tissue specimens were then excised for multiphoton imaging of autofluorescence intensity profiles across the aorta wall. We found that for Days 4 to 48 incubation, autofluorescence is constant along the radial direction of the aorta sections, suggesting that monosaccharide diffusion is rapid in comparison to the rate of formation of fluorescent AGEs (fAGEs). Moreover, we found that in porcine aorta, the rate of fAGE formation of D-fructose and D-glucose are factors 2.08 and 1.14 that of D-galactose. Our results suggest that for prolonged exposure of the cardiovascular system to elevated monosaccharides 4 days or longer, damage to the aorta is uniform throughout the tissues.