Surface responses of aortic valve endothelia from diet-induced, hypercholesterolemic rabbits

Endothelia lining the 2 surfaces (arterial and ventricular) of the posterior cusp of aortic valves from normocholesterolemic, New Zealand white rabbits were found to display pleomorphic surface features characterized by differences in cellular shape and orientation to the direction of blood flow, microappendage populations (microvilli and blebs), nuclear contours and the surface reactions of cationic dyes (RR, AB) and peroxidase-conjugated lectins (Con A, Limulin, WGA). With the aid of SEM and TEM, the cells lining the arterial surfaces appeared relatively smooth and flattened with a moderate to heavy reaction of the carbohydrate cell coat at the blood interface. By contrast, the contours of the endothelia lining the ventricular surfaces were noticeably raised with numerous plasmalemmal microappendages and only a moderate dye/lectin reaction. Observations of similar endothelial populations from diet-induced, hypercholesterolemic rabbits (500 mg/dl) revealed a variety of dramatic changes in the cells lining the arterial surfaces of the valvular cusps. No severe changes were observed in the endothelia of the ventricular surfaces. Such findings are suggestive further of the importance of the interaction between the environment and the endothelial cell coat as influencing factors in the onset of intramural lipid infiltration.