Investigation of the structure of healthy and diseased human ascending aorta by multiphoton microscopy

There have been relatively few examinations of the microstructure of the human ascending aorta and none relating it to the biochemical composition and the tissue mechanics. This study uses multiphoton microscopy, an innovative new tool in biological imaging, to study the structure of the two proteins elastin and collagen in the ascending aorta. Healthy and dilated ascending aortic tissue was examined at two regions, the inner curvature and outer curvature. Dilated aortas were classified by aortic valve type. The morphology of the fenestrations in the elastic laminae and the collagen fibers were quantified. The results show variation of microstructure by aortic valve type and also by region. Correlations between the microstructures and the biochemical composition and the tissue mechanics suggest that multiphoton microscopy could potentially be used for rapid determination of biochemistry and biomechanics of human ascending aortic tissue during surgery. This study demonstrates that vessel wall remodeling occurs with ascending aorta dilation.