Relationship between regional aortic susceptibility to atherosclerosis and macromolecular structural stability

Abstract

The macromolecular structural stability of lesion-free specimens of human aorta was analysed histochemically. In contrast to those sites less susceptible to atherosclerosis (interbranch zones, arch and anterior wall of the thoracic segment), the aortic regions most severely involved by this disease (branch orifices, abdominal portion, posterior wall of the thoracic segment), showed the following characteristics: (i) more rapid and intense dissolution of intimai ground substance mucoproteins following histochemical methods that rupture some non-covalent and covalent linkages; (ii) greater sensitivity to electrostatic-bond-breaking reagents, as shown by the solubility of a hexose-protein fraction which may be the main argyrophilic component of intimai reticulin fibres; (ii) increased solubility (especially with hydrogen-bond-breaking solutions) of the fuchsinophilic material of intimai collagen fibres.