Effects of lipids on elastin's viscoelastic properties

Abstract

Sodium dodecyl sulfate (SDS) was used as a model lipid to identify the molecular basis of possible lipid-induced changes in the viscoelastic behavior of arterial elastin. The chemical composition of the elastin network and the interfibrillar space was calculated from the chemical content of the elastin sample and its swelling behavior. Viscoelastic behavior was measured in aqueous SDS and in SDS plus 1 M sucrose, a deswelling agent. Viscoelastic behavior was also measured in sucrose and potassium thiocyanate solutions to identify the effects of swelling and of changes in network composition exclusive of any direct SDS effects. The hydration of the elastin network decreased at low SDS levels and increased at higher SDS levels. The elastin was stiffer in the dehydrated network and less stiff in the hydrated network. However, once the degree of hydration exceeded that of elastin in pure water, no further decrease in stiffness was obtained despite continued increase in swelling. The stiffness of the network could be accounted for entirely by changes in network hydration. There was no evidence that SDS had any effect on elastin's conformation. We predict that arterial lipids will interact with elastin in a similar way and will have only small effects on elastin's viscoelastic behavior.

Unusual swelling of elastin

“…Sample 3 is shown as a function of SDS content in Figure 4a and b. The behavior at the low concentration indicates that the interaction of SDS with elastin at low SDS levels is complex, and this is dealt with in another paper, 12 but the behavior at higher concentrations indicates a simple swelling regime that can be analyzed to identify the swelling dimensionality of the network.…”

“…Elastin swelling studies in SDS support this prediction. Doubling the SDS concentration from 10 to 20 mM results in only a modest increase in swelling, from 1.26 to 1.29, 12 which would increase to only 81°. Therefore, like the one-dimension model, there is a quantitative match between the reorientation model and the data.…”

High resolutionq‐space imaging studies of water in elastin

“…7 Several thermodynamic studies of elastin have indicated a strong dependence of the Young's modulus with the type of solvent and extent of hydration reinforcing the vital role of an aqueous environment that imparts its elasticity. [8][9][10] The strain dependence of the entropy and energy components of the stress for elastin samples in swelling equilibrium with different diluents has also been investigated. 11 It was shown that in water, the energetic component contributed $15% of the total stress.…”

An integrated laser-tweezers instrument for microanalysis of individual protein aggregates

“…Elastin is a structural protein that helps to maintain the morphology of connective tissues [47][48][49]. At low temperatures, elastin is soluble in aqueous solutions.…”