A reduced glycosaminoglycan-linked residual-strain model captures regional opening angle changes after depletion in the porcine thoracic aorta
Year: 2026
Type: preprint
Abstract: Residual stresses in arteries are commonly revealed by the spring opening of a ring after a radial cut. Glycosaminoglycans (GAGs) contribute to this response, but fixed-charge-density (FCD)-driven Donnan swelling alone does not fully explain the opening-angle reduction measured after enzymatic GAG depletion. We therefore tested whether regional mean depletion responses are consistent with a removable preferred-stretch field shaped by the transmural FCD profile and superposed on a structural field retained after depletion. A reduced analytical-computational axisymmetric closure framework was applied to regional-average measurements from the ascending aorta, arch, and descending porcine thoracic aorta. Each control state was fitted using its measured circumferential opening angle, geometry, material properties, and through-wall FCD profile. GAG depletion was represented by removing the FCD-linked preferred-stretch component. One coefficient governing this removable component was selected jointly from the three measured regional post-depletion angles. A one-layer wall was the primary parsimonious model; a two-layer wall tested anatomical robustness. The one-layer model fitted a shared coefficient of −1.4226 × 10 −3 (mEq / L) −1 and predicted depleted angles of 82.639°, 44.032°, and 19.979°, compared with measured values of 85°, 41°, and 18 ° (three-region RMSE 2.50°). The two-layer model fitted −1.51746 × 10 −3 (mEq / L) −1 and predicted 82.972°, 44.273°, and 18.534 ° (RMSE 2.24°). Thus, layer differentiation improved aggregate fit only modestly. These results show that the three regional mean depletion responses can be represented by one common FCD-linked removable preferred-stretch contribution. Because the model uses regional averages and fitted region-specific control structural fields, it does not establish specimen-level predictive validity or uniquely identify the underlying GAG-mediated mechanism. Donnan swelling remains mechanically relevant, but it is insufficient alone to explain the measured regional response. Statement of Significance Glycosaminoglycans are charged extracellular-matrix constituents that influence arterial residual stress through osmotic effects and interactions with the fibrous matrix. We tested whether the through-wall FCD pattern also defines a removable circumferential preferred-stretch component. One coefficient linking that pattern to the depletion response captured the regional mean post-depletion opening angles of the ascending aorta, arch, and descending aorta within 3.3° using a one-layer model. A two-layer model improved aggregate error only modestly. The result provides a compact mechanistic link between extracellular-matrix composition and residual opening without requiring a separately fitted GAG effect in each region.
Institutions: University of Ottawa, Ottawa Heart Institute
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7169041214