Homeostatic maintenance via degradation and repair of elastic fibers under tension

Abstract

Cellular maintenance of the extracellular matrix requires an effective regulation that balances enzymatic degradation with the repair of collagen fibrils and fibers. Here, we investigate the long-term maintenance of elastic fibers under tension combined with diffusion of general degradative and regenerative particles associated with digestion and repair processes. Computational results show that homeostatic fiber stiffness can be achieved by assuming that cells periodically probe fiber stiffness to adjust the production and release of degradative and regenerative particles. However, this mechanism is unable to maintain a homogeneous fiber. To account for axial homogeneity, we introduce a robust control mechanism that is locally governed by how the binding affinity of particles is modulated by mechanical forces applied to the ends of the fiber. This model predicts diameter variations along the fiber that are in agreement with the axial distribution of collagen fibril diameters obtained from scanning electron microscopic images of normal rat thoracic aorta. The model predictions match the experiments only when the applied force on the fiber is in the range where the variance of local stiffness along the fiber takes a minimum value. Our model thus predicts that the biophysical properties of the fibers play an important role in the long-term regulatory maintenance of these fibers.

Elastic Laminar Reorganization Occurs with Outward Diameter Expansion during Collateral Artery Growth and Requires Lysyl Oxidase for Stabilization

“…Elastic fiber assembly is highly complex and only occurs in development, making vertebrates susceptible to age and disease related degeneration of elastic fibers (34,37,48). Evidence suggests that damaged elastic fibers can be salvaged if the fiber integrity is preserved (49)(50)(51). However, if fiber integrity is lost, disordered elastin synthesis may occur without restoration of functional elastic fibers (52,53).…”

Structural Remodeling of the Extracellular Matrix in Arteriogenesis: A Review

“…This suggests the role of LOX in the repair and stabilization of proteolytically digested elastic fibers during arteriole remodeling. This suggests the proteolytic balance between breakdown and repair during remodeling, possibly related to cross linking of newly synthesized tropoelastin monomers in the later stages of arteriogenesis (31)(32)(33)(34). Notably, increased tropoelastin expression has been seen in models of vascular remodeling previously (120).…”

“…When damaged physiologically or pathologically, elastic fibers can be salvaged if integrity is preserved. Lost elastic fiber integrity may be replaced with disordered elastin synthesis without recovery of elastic function (31)(32)(33)(34)(35).…”

Viscoelastic multiscaling in immersed networks

“…. The inset shows the numerical and the analytical results diverging a little for small times before converging again (for t20). A schematic illustration of the SLS model is shown in (b), with a dashpot of viscosity η and two springs of elastic moduli E 0 and E ∞ .…”

“…We also consider the spring network as a regular lattice. Although complex structures may influence rheological properties of a material, simple geometries have been successfully applied to a large number of problems in mesoscopic models of condensed [17,18] and soft materials [19][20][21].…”