The observation of collagen and elastin structures in wet whole mounts of pulmonary and aortic leaflets.

Porcine pulmonary and aortic heart valve leaflets have been examined as wet whole mounts with the Nomarski differential-contrast imaging technique. The fibrous components, collagen and elastin, which comprise the load-bearing components of the tissue are imaged readily as a function of location on the leaflets as well as of depth through their section. The response of the collagen and elastin structures to applied stress was observed directly with a simple straining device fitted to the microscope stage. I believe that the method has considerable advantages over standard histologic or scanning electron microscope techniques in that detailed structural studies can be related easily to the gross leaflet structure and that there is no interference with the biologic properties of the tissue.