Interaction of low density lipoproteins with human aortic elastin.

Abstract

Binding of radioiodinated low density lipoprotein (LDL) to isolated elastin has been studied in several laboratories.7 -12 However, these studies often involved prolonged incubation periods (18-24 hours) at 21°C or 37°C, and a complex interaction was indicated by continued uptake of LDL by elastin throughout the incubation period. An affinity con- Supported by grant HL-29680 and Research Career Development Award HL-02114 (to J.R.G.) from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md.Address for correspondence: John R. Guyton, MD, The Methodist Hospital, A-601, 6565 Fannin Street, Houston, TX 77030. Received June 8, 1989; revision accepted July 11, 1990. stant for LDL-elastin interaction has not been determined previously.In this article, we report studies of the interaction of radioiodinated human plasma LDL with human aortic elastin, focusing especially on temperature/ time dependence and affinity. We have also investigated the specificity of the interaction and the binding of LDL to elastin isolated from atherosclerotic plaques. Elastin preparations were characterized by amino acid analysis, electron microscopy, and measurement of calcium, hexosamine, and sulfate.

Age-related changes in human macular Bruch's membrane as seen by quick-freeze/deep-etch

“…This may be analogous to the early pathogenesis of an arteriosclerosis that demonstrates LDL depositions in the elastic lamina of the vascular intima (Kramsch and Hollander, 1973;Guyton et al, 1985;Bocan et al, 1988;Podet et al, 1991;Bobryshev and Lord, 1999;Wang et al, 2001). It has been postulated that LDLs can interact with elastin fibrils via hydrophobic amino acids (Bobryshev and Lord, 1999) or by interactions between the oxidized LDL and calcium ion binding elastin fibrils (Wang et al, 2001).…”

Time course of 125I-labeled LDL accumulation in the healing, balloon-deendothelialized rabbit aorta.

“…Consideration of the relative binding affinities of LDL for elastin, glycosaminoglycans, and the cellular high-affinity LDL receptor supports this hypothesis. The interaction between LDL and elastin has been reported to be of moderately high affinity with an apparent dissociation constant (IQ) of 3.6 xlO" 8 M. 42 A weaker interaction has been demonstrated between LDL and heparin, with a /Q between lxlO" 6 M and lxlO" 7 M 18 ; the affinity of LDL for several other glycosaminoglycans, including dermatan sulfate, heparan sulfate, and chondroitin sulfate, has been reported to be even weaker than the affinity of LDL for heparin. 43 Although the affinity of LDL for its highaffinity cell-surface receptor (K,,=2.8xlO' 9 M) 44 is one order of magnitude greater than the affinity of LDL for elastin, binding to the LDL receptor is not likely to be responsible for the persistent focal accumulation of LDL as explained above.…”

The influence of angiotensin-converting enzyme inhibitors on the aorta elastin metabolism in diet-induced hypercholesterolaemia in rabbits

“…Calcium overload, producing calcification of lamina media elastic fibres, leads to a decrease in aortic elasticity parameters in rats. [32][33][34][35] In the aortae of cholesterol-fed rabbits, the elastinbound calcium content was significantly higher than in the control group. Higher doses of captopril and enalapril decrease the elastin-bound calcium content of aortic extracts.…”